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Sample records for acidophilus strain np51

  1. Prevention of Mycobacterium avium subsp. paratuberculosis Infection in BALB/c Mice by Feeding Lactobacillus acidophilus Strain NP-51

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The immune responses of 390 BALB/c mice fed the probiotic Lactobacillus acidophilus strain NP51® and infected with Mycobacterium avium subspecies paratuberculosis (MAP) were evaluated in a 6-month trial. Mice were randomized to nine treatment groups fed either viable- or heat-killed NP51 and inocula...

  2. Prevention of Mycobacterium avium subsp. paratuberculosis (MAP) Infection in Balb/c Mice by Feeding Probiotic Lactobacillus acidophilus NP-51

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective of this study was to examine effects of feeding Lactobacillus acidophilus strain NP51 to mice challenged with Mycobacterium avium subspecies paratuberculosis (MAP), the causative agent of Johne’s disease. We hypothesized that feeding NP51 would increase Th-1 responses and decrease prog...

  3. Prevention of Mycobacterium avium subsp. paratuberculosis (MAP) infection in BALB/c mice by feeding probiotic Lactobacillus acidophilus NP-51

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective of this study was to examine effects of feeding Lactobacillus acidophilus strain NP51 to mice challenged with Mycobacterium avium subspecies paratuberculosis (MAP). Mice were randomized to ten treatment groups; sentinels, control, heat-killed MAP, viable MAP, heat-killed NP51, viable ...

  4. Prevention of Mycobacterium avium subsp. paratuberculosis (MAP) infection in Balb/c mice by feeding probiotic Lactobacillus acidophilus NP-51

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective of this study was to examine effects of feeding Lactobacillus acidophilus strain NP51 to mice challenged with Mycobacterium avium subspecies paratuberculosis (MAP), the causative agent of Johne’s disease. We hypothesized that feeding NP51 would increase Th-1 responses and decrease prog...

  5. Prevention of Mycobacterium avium subsp. paratuberculosis (MAP) Infection in BALB/c Mice by Feeding Probiotic Lactobacillus acidophilus NP-51

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective of this study was to examine effects of feeding Lactobacillus acidophilus strain NP51 to mice challenged with Mycobacterium avium subspecies paratuberculosis (MAP). Mice were randomized to ten treatment groups; sentinels, control, heat-killed MAP, viable MAP, heat-killed NP51, viable ...

  6. The other way around: probiotic Lactobacillus acidophilus NP51 restrict progression of Mycobacterium avium subspecies paratuberculosis (MAP) infection in Balb/c mice via activiation of CD8 alpha+ immune cell-mediated immunity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective of this study was to examine the immune-modulating effects of feeding a novel probiotic Lactobacillus acidophilus strain NP51 to specific pathogen-free Balb/c mice challenged with Mycobacterium avium subspecies paratuberculosis (MAP), the causative agent of Johne’s disease (JD) in rumi...

  7. The other way around: Probiotic lactobacillus acidophilus NP51 restricts progression of Mycobacterium avium subspecies paratuberculosis (MAP) infection in Balb/c mice through activation of CD8+ T cell-mediated immunity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective of this study was to examine immune effects of feeding novel probiotic Lactobacillus acidophilus strain NP51 to specific pathogen-free Balb/c mice challenged with Mycobacterium avium subspecies paratuberculosis (MAP), the causative agent of Johne’s disease (JD). We hypothesized that fe...

  8. Betaine Transport Imparts Osmotolerance on a Strain of Lactobacillus acidophilus

    PubMed Central

    Hutkins, Robert W.; Ellefson, William L.; Kashket, Eva R.

    1987-01-01

    Unlike most Lactobacillus acidophilus strains, a specific strain, L. acidophilus IFO 3532, was found to grow in rich medium containing 1 M sodium acetate, KCl, or NaCl. This strain could also grow with up to 1.8 M NaCl or 3 M nonelectrolytes (fructose, xylose, or sorbitol) added. Thus, this strain was tolerant to osmotic pressures up to 2.8 osM. A search for an intracellular solute which conferred osmoprotection led to the identification of glycine betaine (betaine). Betaine was accumulated to high concentrations in cells growing in MRS medium supplemented with 1 M KCl or NaCl. Uptake of [14C]betaine by L. acidophilus 3532 cells suspended in buffer was stimulated by increasing the medium osmotic pressure with 1 M KCl or NaCl. The accumulated betaine was not metabolized further; transport was relatively specific for betaine and was dependent on an energy source. Other lactobacilli, more osmosensitive than strain 3532, including L. acidophilus strain E4356, L. bulgaricus 8144, and L. delbrueckii 9649, showed lower betaine transport rates in response to an osmotic challenge than L. acidophilus 3532. Experiments with chloramphenicol-treated L. acidophilus 3532 cells indicated that the transport system was not induced but appeared to be activated by an increase in osmotic pressure. PMID:16347448

  9. Genotyping by randomly amplified polymorphic DNA of bacteriocin producing Lactobacillus acidophilus strains from Nigeria.

    PubMed

    Alli, John Adeolu; Iwalokun, Bamidele A; Oluwadun, Afolabi; Okonko, Iheanyi Omezuruike

    2015-01-01

    Yogurt and starter culture producers are still searching strains of Lactobacillus acidophilus to produce healthier yogurt with a longer shelf life and better texture, taste, and quality. This study determined the genotyping of bacteriocin producing Lactobacillus acidophilus strains recovered from Nigerian yogurts. Yogurt samples were collected from four different states of South West regions of Nigeria. Isolates were obtained from MRS Medium and biochemically characterized. This was further confirmed by API50CH. The bacteriocin positivity and activity was determined. Genomic characterization of our Lactobacillus acidophilus strains was done with randomly amplified polymorphic DNA-PCR. All yogurt samples containing Lactobacillus acidophilus strains meet the probiotic requirement of ≥10(6) cfu/mL. The gel picture revealed 6 RAPD clonal types of Lactobacillus acidophilus strains with RAPD type C observed to be more common. Significant differences existed in the mean growth inhibition zone (t = -7.32, P < 0.05 for E. coli ATCC; t = -6.19, P < 0.05 for E. coli clinical isolates; t = -6.16, P < 0.05 for Enterobacter sp; t = -11.92, P < 0.05 for Salmonella typhi, t = -1.10, P > 0.05 Staphylococcus aureus). No correlation between the bacteriocin production, activity, and their RAPD clonal division (X(2) = 7.49, P = 0.1610, df = 5). In conclusion, L. acidophilus isolated in Nigeria samples met the probiotic requirements of ≥10(6) cfu/mL and produce bacteriocins with good spectrum of activity.

  10. Complete genome analysis of Sulfobacillus acidophilus strain TPY, isolated from a hydrothermal vent in the Pacific Ocean.

    PubMed

    Li, Bo; Chen, Yaping; Liu, Qian; Hu, Songnian; Chen, Xinhua

    2011-10-01

    Sulfobacillus acidophilus strain TPY is a moderately thermoacidophilic bacterium originally isolated from a hydrothermal vent in the Pacific Ocean. Ferrous iron and sulfur oxidation in acidic environments in strain TPY have been confirmed. Here we report the genome sequence and annotation of the strain TPY, which is the first complete genome of Sulfobacillus acidophilus.

  11. Probiotic potential and biotherapeutic effects of newly isolated vaginal Lactobacillus acidophilus 36YL strain on cancer cells.

    PubMed

    Nami, Yousef; Abdullah, Norhafizah; Haghshenas, Babak; Radiah, Dayang; Rosli, Rozita; Khosroushahi, Ahmad Yari

    2014-08-01

    Lactobacillus acidophilus is categorized as a probiotic strain because of its beneficial effects in human health and prevention of disease transmission. This study is aimed to characterize the probiotic potential of L. acidophilus 36YL originally isolated from the vagina of healthy and fertile Iranian women. The L. acidophilus 36YL strain was identified using 16S rDNA gene sequencing and characterized by biochemical methodologies, such as antibiotics susceptibility, antimicrobial activity, and acid and bile resistance. The bioactivity of the secretion of this strain on four human cancer cell lines (AGS, HeLa, MCF-7, and HT-29) and one normal cell line (HUVEC) was evaluated by cytotoxicity assay and apoptosis analysis. This newly isolated strain was found to exhibit notable probiotic properties, such as admirable antibiotic susceptibility, good antimicrobial activity, and favorable resistance to acid and bile salt. The results of bioactivity assessment demonstrated acceptable anticancer effects on the four tested cancer cell lines and negligible side effects on the assayed normal cell line. Our findings revealed that the anticancer effect of L. acidophilus 36YL strain secretions depends on the induction of apoptosis in cancer cells. L. acidophilus 36YL strain is considered as a nutraceutical alternative or a topical medication with a potential therapeutic index because of the absence of cytotoxicity to normal cells, but effective toxicity to cancer cell lines.

  12. Caenorhabditis elegans immune conditioning with the probiotic bacterium Lactobacillus acidophilus strain NCFM enhances gram-positive immune responses.

    PubMed

    Kim, Younghoon; Mylonakis, Eleftherios

    2012-07-01

    Although the immune response of Caenorhabditis elegans to microbial infections is well established, very little is known about the effects of health-promoting probiotic bacteria on evolutionarily conserved C. elegans host responses. We found that the probiotic Gram-positive bacterium Lactobacillus acidophilus NCFM is not harmful to C. elegans and that L. acidophilus NCFM is unable to colonize the C. elegans intestine. Conditioning with L. acidophilus NCFM significantly decreased the burden of a subsequent Enterococcus faecalis infection in the nematode intestine and prolonged the survival of nematodes exposed to pathogenic strains of E. faecalis and Staphylococcus aureus, including multidrug-resistant (MDR) isolates. Preexposure of nematodes to Bacillus subtilis did not provide any beneficial effects. Importantly, L. acidophilus NCFM activates key immune signaling pathways involved in C. elegans defenses against Gram-positive bacteria, including the p38 mitogen-activated protein kinase pathway (via TIR-1 and PMK-1) and the β-catenin signaling pathway (via BAR-1). Interestingly, conditioning with L. acidophilus NCFM had a minimal effect on Gram-negative infection with Pseudomonas aeruginosa or Salmonella enterica serovar Typhimurium and had no or a negative effect on defense genes associated with Gram-negative pathogens or general stress. In conclusion, we describe a new system for the study of probiotic immune agents and our findings demonstrate that probiotic conditioning with L. acidophilus NCFM modulates specific C. elegans immunity traits.

  13. Complete genome sequence of the moderately thermophilic mineral-sulfide-oxidizing firmicute Sulfobacillus acidophilus type strain (NALT)

    SciTech Connect

    Anderson, Iain; Chertkov, Olga; Chen, Amy; Saunders, Elizabeth H; Lapidus, Alla L.; Nolan, Matt; Lucas, Susan; Hammon, Nancy; Deshpande, Shweta; Cheng, Jan-Fang; Han, Cliff; Tapia, Roxanne; Goodwin, Lynne A.; Pitluck, Sam; Liolios, Konstantinos; Pagani, Ioanna; Ivanova, N; Mikhailova, Natalia; Pati, Amrita; Palaniappan, Krishna; Land, Miriam L; Pan, Chongle; Rohde, Manfred; Pukall, Rudiger; Goker, Markus; Detter, J. Chris; Woyke, Tanja; Bristow, James; Eisen, Jonathan; Markowitz, Victor; Hugenholtz, Philip; Kyrpides, Nikos C; Klenk, Hans-Peter; Mavromatis, K

    2012-01-01

    Sulfobacillus acidophilus Norris et al. 1996 is a member of the genus Sulfobacillus which comprises five species of the order Clostridiales. Sulfobacillus species are of interest for comparison to other sulfur and iron oxidizers and also have biomining applications. This is the first completed genome sequence of a type strain of the genus Sulfobacillus, and the second published genome of a member of the species S. acidophilus. The genome, which consists of one chromosome and one plasmid with a total size of 3,557,831 bp, harbors 3,626 protein-coding and 69 RNA genes, and is a part of the Genomic Encyclopedia of Bacteria and Archaea project.

  14. Selection of the Strain Lactobacillus acidophilus ATCC 43121 and Its Application to Brewers' Spent Grain Conversion into Lactic Acid

    PubMed Central

    Liguori, Rossana; Soccol, Carlos Ricardo; Vandenberghe, Luciana Porto de Souza; Woiciechowski, Adenise Lorenci; Ionata, Elena; Marcolongo, Loredana; Faraco, Vincenza

    2015-01-01

    Six Lactobacillus strains were analyzed to select a bacterium for conversion of brewers' spent grain (BSG) into lactic acid. Among the investigated strains, L. acidophilus ATCC 43121 showed the highest yield of lactic acid production (16.1 g/L after 48 hours) when grown in a synthetic medium. It was then analyzed for its ability to grow on the hydrolysates obtained from BSG after acid-alkaline (AAT) or aqueous ammonia soaking (AAS) pretreatment. The lactic acid production by L. acidophilus ATCC 43121 through fermentation of the hydrolysate from AAS treated BSG was 96% higher than that from the AAT treated one, although similar yields of lactic acid per consumed glucose were achieved due to a higher (46%) glucose consumption by L. acidophilus ATCC 43121 in the AAS BSG hydrolysate. It is worth noting that adding yeast extract to the BSG hydrolysates increased both the yield of lactic acid per substrate consumed and the volumetric productivity. The best results were obtained by fermentation of AAS BSG hydrolysate supplemented by yeast extract, in which the strain produced 22.16 g/L of lactic acid (yield of 0.61 g/g), 27% higher than the value (17.49 g/L) obtained in the absence of a nitrogen source. PMID:26640784

  15. Selection of the Strain Lactobacillus acidophilus ATCC 43121 and Its Application to Brewers' Spent Grain Conversion into Lactic Acid.

    PubMed

    Liguori, Rossana; Soccol, Carlos Ricardo; Vandenberghe, Luciana Porto de Souza; Woiciechowski, Adenise Lorenci; Ionata, Elena; Marcolongo, Loredana; Faraco, Vincenza

    2015-01-01

    Six Lactobacillus strains were analyzed to select a bacterium for conversion of brewers' spent grain (BSG) into lactic acid. Among the investigated strains, L. acidophilus ATCC 43121 showed the highest yield of lactic acid production (16.1 g/L after 48 hours) when grown in a synthetic medium. It was then analyzed for its ability to grow on the hydrolysates obtained from BSG after acid-alkaline (AAT) or aqueous ammonia soaking (AAS) pretreatment. The lactic acid production by L. acidophilus ATCC 43121 through fermentation of the hydrolysate from AAS treated BSG was 96% higher than that from the AAT treated one, although similar yields of lactic acid per consumed glucose were achieved due to a higher (46%) glucose consumption by L. acidophilus ATCC 43121 in the AAS BSG hydrolysate. It is worth noting that adding yeast extract to the BSG hydrolysates increased both the yield of lactic acid per substrate consumed and the volumetric productivity. The best results were obtained by fermentation of AAS BSG hydrolysate supplemented by yeast extract, in which the strain produced 22.16 g/L of lactic acid (yield of 0.61 g/g), 27% higher than the value (17.49 g/L) obtained in the absence of a nitrogen source.

  16. Application of Lactobacillus acidophilus (LA 5) strain in fruit-based ice cream.

    PubMed

    Senanayake, Suraji A; Fernando, Sirimali; Bamunuarachchi, Arthur; Arsekularatne, Mariam

    2013-11-01

    A study was performed to apply a probiotic strain into fermented ice cream mix with suitable fruit bases to develop a value-added product with a substantial level of viable organisms for a sufficient shelf life. Pure direct vat strain culture of Lactobacillus acidophilus (LA 5) in freeze-dried form was inoculated into a mixture of ice cream, frozen, and the number of viable organisms during frozen storage for a period of time was enumerated, using turbidity measurements with a spectrophotometer. An ice cream sample prepared without the probiotic culture was compared with the test sample for quality, by testing the basic quality parameters for ice cream. Results show a reduction in the over run of the probiotic ice cream compared to the nonprobiotic ice cream. Significantly high level (P < 0.05) of total solids (42%), proteins (16.5%), and titratable acidity (2.2%) was observed in the test sample compared to the nonprobiotic ice cream. Significantly low pH level in the probiotic sample may be due to the lactic acid produced by the probiotic culture. No significant difference (P > 0.05) in the fat content in the two types of ice cream was observed. A significantly low level (P < 0.05) of melting in the probiotic one may have resulted from less over run, than the nonprobiotic sample. Rapid reduction in the viable cells during frozen storage occurred at -18°C and gradual adaptation occurred over the first 4 weeks. At the 10th week, 1.0 × 10(7) numbers of viable organisms were present in 1 g of the probiotic ice cream. Results show the presence of a sufficient number of viable organisms in the product for the 10-week period, which would be beneficial to consumers.

  17. Application of Lactobacillus acidophilus (LA 5) strain in fruit-based ice cream

    PubMed Central

    Senanayake, Suraji A; Fernando, Sirimali; Bamunuarachchi, Arthur; Arsekularatne, Mariam

    2013-01-01

    A study was performed to apply a probiotic strain into fermented ice cream mix with suitable fruit bases to develop a value-added product with a substantial level of viable organisms for a sufficient shelf life. Pure direct vat strain culture of Lactobacillus acidophilus (LA 5) in freeze-dried form was inoculated into a mixture of ice cream, frozen, and the number of viable organisms during frozen storage for a period of time was enumerated, using turbidity measurements with a spectrophotometer. An ice cream sample prepared without the probiotic culture was compared with the test sample for quality, by testing the basic quality parameters for ice cream. Results show a reduction in the over run of the probiotic ice cream compared to the nonprobiotic ice cream. Significantly high level (P < 0.05) of total solids (42%), proteins (16.5%), and titratable acidity (2.2%) was observed in the test sample compared to the nonprobiotic ice cream. Significantly low pH level in the probiotic sample may be due to the lactic acid produced by the probiotic culture. No significant difference (P > 0.05) in the fat content in the two types of ice cream was observed. A significantly low level (P < 0.05) of melting in the probiotic one may have resulted from less over run, than the nonprobiotic sample. Rapid reduction in the viable cells during frozen storage occurred at −18°C and gradual adaptation occurred over the first 4 weeks. At the 10th week, 1.0 × 107 numbers of viable organisms were present in 1 g of the probiotic ice cream. Results show the presence of a sufficient number of viable organisms in the product for the 10-week period, which would be beneficial to consumers. PMID:24804052

  18. Derivation of DNA probes for enumeration of a specific strain of Lactobacillus acidophilus in piglet digestive tract samples.

    PubMed Central

    Rodtong, S; Dobbinson, S; Thode-Andersen, S; McConnell, M A; Tannock, G W

    1993-01-01

    Four DNA probes were derived that hybridized specifically to DNA from Lactobacillus acidophilus O. The probes were constructed by randomly cloning lactobacillus DNA in plasmid vector pBR322. Two of the probes (pSR1 and pSR2) were composed of vector and plasmid DNA inserts (3.6 and 1.6 kb, respectively); the others (pSR3 and pSR4) were composed of vector and chromosomally derived inserts (6.9 and 1.4 kb, respectively). The probes were used to enumerate, by colony hybridization, strain O in digestive tract samples collected from piglets inoculated 24 hours previously with a culture of the strain. The probes did not hybridize to DNA from lactobacilli inhabiting the digestive tract of uninoculated piglets. Strain O made up about 10% of the total lactobacillus population of the pars esophagea and about 20% of the population in other digestive tract samples. Images PMID:8285690

  19. The human Lactobacillus acidophilus strain LA1 secretes a nonbacteriocin antibacterial substance(s) active in vitro and in vivo.

    PubMed Central

    Bernet-Camard, M F; Liévin, V; Brassart, D; Neeser, J R; Servin, A L; Hudault, S

    1997-01-01

    The adhering human Lactobacillus acidophilus strain LA1 inhibits the cell association and cell invasion of enteropathogens in cultured human intestinal Caco-2 cells (M. F. Bernet, D. Brassard, J. R. Neeser, and A. L. Servin, Gut 35:483-489, 1994). Here, we demonstrate that strain LA1 developed its antibacterial activity in conventional or germ-free mouse models orally infected by Salmonella typhimurium. We present evidence that the spent culture supernatant of strain LA1 (LA1-SCS) contained antibacterial components active against S. typhimurium infecting the cultured human intestinal Caco-2 cells. The LA1-SCS antibacterial activity was observed in vitro against a wide range of gram-negative and gram-positive pathogens, such as Staphylococcus aureus, Listeria monocytogenes, S. typhimurium, Shigella flexneri, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Enterobacter cloacae. By contrast, no activity was observed against species of the normal gut flora, such as lactobacilli and bifidobacteria. The LA1-SCS antibacterial activity was insensitive to proteases and independent of lactic acid production. PMID:9212421

  20. Eruca sativa Might Influence the Growth, Survival under Simulated Gastrointestinal Conditions and Some Biological Features of Lactobacillus acidophilus, Lactobacillus plantarum and Lactobacillus rhamnosus Strains

    PubMed Central

    Fratianni, Florinda; Pepe, Selenia; Cardinale, Federica; Granese, Tiziana; Cozzolino, Autilia; Coppola, Raffaele; Nazzaro, Filomena

    2014-01-01

    The growth and viability of three Lactobacillus strains, Lactobacillus acidophilus, Lactobacillus plantarum and Lactobacillus rhamnosus, after their passage through simulated gastric and pancreatic juices were studied as a function of their presence in the growth medium of rocket salad (Eruca sativa). The presence of E. sativa affected some of the biological properties of the strains. For example, L. acidophilus and L. plantarum worked more efficiently in the presence of E. sativa, increasing not only the antioxidant activity of the medium, but also their own antioxidant power and antimicrobial activity; L. rhamnosus was not affected in the same manner. Overall, the presence of vegetables might help to boost, in specific cases, some of the characteristics of lactobacilli, including antioxidant and antimicrobial power. PMID:25275269

  1. Eruca sativa might influence the growth, survival under simulated gastrointestinal conditions and some biological features of Lactobacillus acidophilus, Lactobacillus plantarum and Lactobacillus rhamnosus strains.

    PubMed

    Fratianni, Florinda; Pepe, Selenia; Cardinale, Federica; Granese, Tiziana; Cozzolino, Autilia; Coppola, Raffaele; Nazzaro, Filomena

    2014-10-01

    The growth and viability of three Lactobacillus strains, Lactobacillus acidophilus, Lactobacillus plantarum and Lactobacillus rhamnosus, after their passage through simulated gastric and pancreatic juices were studied as a function of their presence in the growth medium of rocket salad (Eruca sativa). The presence of E. sativa affected some of the biological properties of the strains. For example, L. acidophilus and L. plantarum worked more efficiently in the presence of E. sativa, increasing not only the antioxidant activity of the medium, but also their own antioxidant power and antimicrobial activity; L. rhamnosus was not affected in the same manner. Overall, the presence of vegetables might help to boost, in specific cases, some of the characteristics of lactobacilli, including antioxidant and antimicrobial power.

  2. Screening, Isolation and Identification of Probiotic Producing Lactobacillus acidophilus Strains EMBS081 & EMBS082 by 16S rRNA Gene Sequencing.

    PubMed

    Chandok, Harshpreet; Shah, Pratik; Akare, Uday Raj; Hindala, Maliram; Bhadoriya, Sneha Singh; Ravi, G V; Sharma, Varsha; Bandaru, Srinivas; Rathore, Pragya; Nayarisseri, Anuraj

    2015-09-01

    16S rDNA sequencing which has gained wide popularity amongst microbiologists for the molecular characterization and identification of newly discovered isolates provides accurate identification of isolates down to the level of sub-species (strain). Its most important advantage over the traditional biochemical characterization methods is that it can provide an accurate identification of strains with atypical phenotypic characters as well. The following work is an application of 16S rRNA gene sequencing approach to identify a novel species of Probiotic Lactobacillus acidophilus. The sample was collected from pond water samples of rural and urban areas of Krishna district, Vijayawada, Andhra Pradesh, India. Subsequently, the sample was serially diluted and the aliquots were incubated for a suitable time period following which the suspected colony was subjected to 16S rDNA sequencing. The sequence aligned against other species was concluded to be a novel, Probiotic L. acidophilus bacteria, further which were named L. acidophilus strain EMBS081 & EMBS082. After the sequence characterization, the isolate was deposited in GenBank Database, maintained by the National Centre for Biotechnology Information NCBI. The sequence can also be retrieve from EMBL and DDBJ repositories with accession numbers JX255677 and KC150145.

  3. Antibacterial activity of Lactobacillus acidophilus strains isolated from honey marketed in Malaysia against selected multiple antibiotic resistant (MAR) Gram-positive bacteria.

    PubMed

    Aween, Mohamed Mustafa; Hassan, Zaiton; Muhialdin, Belal J; Eljamel, Yossra A; Al-Mabrok, Asma Saleh W; Lani, Mohd Nizam

    2012-07-01

    A total of 32 lactic acid bacteria (LAB) were isolated from 13 honey samples commercially marketed in Malaysia, 6 strains identified as Lactobacillus acidophilus by API CHL50. The isolates had antibacterial activities against multiple antibiotic resistant's Staphylococcus aureus (25 to 32 mm), Staphylococcus epidermis (14 to 22 mm) and Bacillus subtilis (12 to 19 mm) in the agar overlay method after 24 h incubation at 30 °C. The crude supernatant was heat stable at 90 °C and 121 °C for 1 h. Treatment with proteinase K and RNase II maintained the antimicrobial activity of all the supernatants except sample H006-A and H010-G. All the supernatants showed antimicrobial activities against target bacteria at pH 3 and pH 5 but not at pH 6 within 72 h incubation at 30 °C. S. aureus was not inhibited by sample H006-A isolated from Libyan honey and sample H008-D isolated from Malaysian honey at pH 5, compared to supernatants from other L. acidophilus isolates. The presence of different strains of L. acidophilus in honey obtained from different sources may contribute to the differences in the antimicrobial properties of honey.

  4. Bacteriocin production and resistance to drugs are advantageous features for Lactobacillus acidophilus La-14, a potential probiotic strain.

    PubMed

    Todorov, Svetoslav Dimitrov; Furtado, Danielle Nader; Saad, Susana Marta Isay; Gombossy de Melo Franco, Bernadette Dora

    2011-10-01

    L. acidophilus La-14 produces bacteriocin active against L. monocytogenes ScottA (1600 AU/ml) in MRS broth at 30°C or 37°C. The bacteriocin proved inhibitory to different serological types of Listeria spp. Antimicrobial activity was completely lost after treatment of the cell-free supernatant with proteolytic enzymes. Addition of bacteriocin produced by L. acidophilus La-14 to a 3 h-old culture of L. monocytogenes ScottA repressed cell growth in the following 8h. Treatment of stationary phase cells of L. monocytogenes ScottA (107-108 CFU/ml) by the bacteriocin resulted in growth inhibition. Growth of L. acidophilus La-14 was not inhibited by commercial drugs from different generic groups, including nonsteroidal anti-inflammatory drugs (NSAID) containing diclofenac potassium or ibuprofen arginine. Only one non-antibiotic drug tested, Atlansil (an antiarrhythmic agent), had an inhibitory effect on L. acidophilus La-14 with MIC of 2.5 mg/ml. L. acidophilus La-14 was not affected by drugs containing sodium or potassium diclofenac. L. acidophilus La-14 shows a good resistance to several drugs and may be applied in combination for therapeutic use.

  5. Reprogramming Intestinal Immunity by Novel L. Acidophilus Strains Results in Protective Immunity against Colon Cancer

    DTIC Science & Technology

    2015-11-01

    important advances in detection, surgery and chemotherapy. An imbalance of commensal bacteria and their gene products underlie mucosal and, in...compelling evidence in defining the SlpA of this NCK2025 strain as playing the critical role in the protection against murine colitis and polyposis. Thus, we...the natural mouse microbiota, which was not evident in Signr3-/- mice (Fig. 6C-D). Importantly, both NCK2187 and its purified SlpA also significantly

  6. Safety assessment of potential probiotic lactic acid bacterial strains Lactobacillus rhamnosus HN001, Lb. acidophilus HN017, and Bifidobacterium lactis HN019 in BALB/c mice.

    PubMed

    Zhou, J S; Shu, Q; Rutherfurd, K J; Prasad, J; Birtles, M J; Gopal, P K; Gill, H S

    2000-05-25

    The general safety of immune-enhancing lactic acid bacteria (LAB) strains Lactobacillus rhamnosus HN001 (DR20), Lb. acidophilus HN017, and Bifidobacterium lactis HN019 (DR10) was investigated in a feeding trial. Groups of BALB/c mice were orally administered test LAB strains or the commercial reference strain Lb. acidophilus LA-1 at 2.5 x 10(9), 5 x 10(10) or 2.5 x 10(12) colony forming units (CFU)/kg body weight/day for 4 weeks. Throughout this time, their feed intake, water intake, and live body weight were monitored. At the end of the 4 week observation period, samples of blood, liver, spleen, kidney, mesenteric lymph nodes, and gut tissues (ileum, caecum, and colon) were collected to determine: haematological parameters (red blood cell and platelet counts, haemoglobin concentration, mean corpuscular volume, mean corpuscular haemoglobin, and mean corpuscular haemoglobin concentration); differential leukocyte counts; blood biochemistry (plasma total protein, albumin, cholesterol, and glucose); mucosal histology (epithelial cell height, mucosal thickness, and villus height); and bacterial translocation to extra-gut tissues (blood, liver, spleen, kidney and mesenteric lymph nodes). DNA finger printing techniques were used to identify any viable bacterial strains recovered from these tissues. The results demonstrated that 4 weeks consumption of these LAB strains had no adverse effects on animals' general health status, haematology, blood biochemistry, gut mucosal histology parameters, or the incidence of bacterial translocation. A few viable LAB cells were recovered from the tissues of animals in both control and test groups, but DNA fingerprinting did not identify any of these as the inoculated strains. The results obtained in this study suggest that the potentially probiotic LAB strains HN001, HN017, and HN019 are non-toxic for mice and are therefore likely to be safe for human use.

  7. The domestication of the probiotic bacterium Lactobacillus acidophilus.

    PubMed

    Bull, Matthew J; Jolley, Keith A; Bray, James E; Aerts, Maarten; Vandamme, Peter; Maiden, Martin C J; Marchesi, Julian R; Mahenthiralingam, Eshwar

    2014-11-26

    Lactobacillus acidophilus is a Gram-positive lactic acid bacterium that has had widespread historical use in the dairy industry and more recently as a probiotic. Although L. acidophilus has been designated as safe for human consumption, increasing commercial regulation and clinical demands for probiotic validation has resulted in a need to understand its genetic diversity. By drawing on large, well-characterised collections of lactic acid bacteria, we examined L. acidophilus isolates spanning 92 years and including multiple strains in current commercial use. Analysis of the whole genome sequence data set (34 isolate genomes) demonstrated L. acidophilus was a low diversity, monophyletic species with commercial isolates essentially identical at the sequence level. Our results indicate that commercial use has domesticated L. acidophilus with genetically stable, invariant strains being consumed globally by the human population.

  8. Genetic and functional aspects of linoleate isomerase in Lactobacillus acidophilus.

    PubMed

    Macouzet, Martin; Robert, Normand; Lee, Byong H

    2010-08-01

    While the remarkable health effects of conjugated linoleic acid (CLA) catalyzed from alpha-linoleic acid by the enzyme linoleate isomerase (LI, EC 5.2.1.5) are well recognized, how widely this biochemical activity is present and the mechanisms of its regulation in lactic acid bacteria are unknown. Although certain strains of Lactobacillus acidophilus can enrich CLA in fermented dairy products, it is unknown if other strains share this capacity. Due to its immense economic importance, this work aimed to investigate genetic aspects of CLA production in L. acidophilus for the first time. The genomic DNA from industrial and type strains of L. acidophilus were subjected to PCR and immunoblot analyses using the putative LI gene of L. reuteri ATCC 55739 as probe. The CLA production ability was estimated by gas chromatography of the biomass extracts. The presumptive LI gene from L. acidophilus ATCC 832 was isolated and sequenced. The resulting sequence shared 71% identity with that of L. reuteri and at least 99% with reported sequences from other L. acidophilus strains. All the strains accumulated detectable levels of CLA and tested positive by PCR and immunoblotting. However, no apparent correlation was observed between the yields and the hybridization patterns. The results suggest that LI activity might be common among L. acidophilus and related species and provide a new tool for screening potential CLA producers.

  9. Inhibitory effect of Lactobacillus acidophilus on Helicobacter hepaticus in vitro.

    PubMed

    Zhang, Manhua; Zhang, Haiyang; Li, Yan; Qi, Wenqian; Wang, Xu; Wang, Jiangbin

    2013-03-01

    Helicobacter hepaticus and Helicobacter pylori both belong to Helicobacter species. Strains of Lactobacillus acidophilus, including L4 and L6, have shown significant inhibitory effects on H. pylori. Based on this phenomenon, we aim to investigate the inhibitory effect of L. acidophilus on H. hepaticus. Both standard and isolated H. hepaticus strains were grown under microaerophilic conditions at 37 °C in the presence of L. acidophilus supernatant, or lactic acid. The diameters of the inhibition zones were measured on the solid culture media. In liquid culture, the cell concentrations were measured and the urease activity was determined by phenol red staining. Sixteen strains of L. acidophilus isolated from human feces (named as L1-L16) showed anti-H. hepaticus effects. Two of them (L4 and L6) exhibited the most apparent effects on H. hepaticus inhibition. The L. acidophilus supernatant of L4 and L6 significantly increased the diameters of the inhibition zones compared with that of the lactic acid control (P < 0.05). The inhibitory role of L. acidophilus supernatant was independent of the pH value of solution (P > 0.05). Moreover, in liquid culture, L. acidophilus supernatant significantly reduced the cell growth rate and the urease activity of H. hepaticus cells in a time-dependent pattern (P < 0.05 compared with lactic acid control). No obvious difference was observed between the standard and isolated strain of H. hepaticus (P > 0.05). Our results indicate that L. acidophilus can decrease the viability and urease activity of H. hepaticus in vitro and this inhibition is independent of pH levels. This provides evidence for developing novel approaches for the prevention and treatment of H. hepaticus infection.

  10. The life history of Lactobacillus acidophilus as a probiotic: a tale of revisionary taxonomy, misidentification and commercial success.

    PubMed

    Bull, Matthew; Plummer, Sue; Marchesi, Julian; Mahenthiralingam, Eshwar

    2013-12-01

    Lactobacillus acidophilus is a commercially significant bacterial probiotic, originally isolated from the human gastrointestinal tract and designated Bacillus acidophilus in 1900. Throughout the development of methods to identify and characterise bacteria, L. acidophilus has undergone multiple taxonomic revisions and is now the type species of a phylogenetic subgroup in the highly diverse and heterogeneous Lactobacillus genus. As a result of the limitations of differentiating phenotypically similar species by morphological and biochemical means and revisionary nature of Lactobacillus taxonomy, the characterisation of L. acidophilus has struggled with misidentification and misrepresentation. In contrast, due to its global use as a probiotic supplement in functional foods, L. acidophilus sensu stricto is now one of the most well-characterised Lactobacillus species. Here, we establish the provenance of L. acidophilus strains, unpicking historical and current misidentifications of L. acidophilus, and reviewing the probiotic, genomic and physiological characteristics of this important Lactobacillus species.

  11. Lactobacillus acidophilus modulates the virulence of Clostridium difficile.

    PubMed

    Yun, B; Oh, S; Griffiths, M W

    2014-01-01

    Clostridium difficile is a spore-forming, toxin-producing, anaerobic bacterium that colonizes the human gastrointestinal tract. This pathogen causes antibiotic-associated diarrhea and colitis in animals and humans. Antibiotic-associated diseases may be treated with probiotics, and interest is increasing in such uses of probiotics. This study investigated the effect of Lactobacillus strains on the quorum-sensing signals and toxin production of C. difficile. In addition, an in vivo experiment was designed to assess whether Lactobacillus acidophilus GP1B is able to control C. difficile-associated disease. Autoinducer-2 activity was measured for C. difficile using the Vibrio harveyi coupled bioluminescent assay. Cell extract (10μg/mL) of L. acidophilus GP1B exhibited the highest inhibitory activity among 5 to 40μg/mL cell-extract concentrations. Real-time PCR data indicated decreased transcriptional levels in luxS, tcdA, tcdB, and txeR genes in the presence of 10μg/mL of cell extract of L. acidophilus GP1B. Survival rates at 5d for mice given the pathogen alone with L. acidophilus GP1B cell extract or L. acidophilus GP1B were 10, 70, and 80%, respectively. In addition, the lactic acid-produced L. acidophilus GP1B exhibits an inhibitory effect against the growth of C. difficile. Both the L. acidophilus GP1B and GP1B cell extract have significant antipathogenic effects on C. difficile.

  12. Drug resistance plasmids in Lactobacillus acidophilus and Lactobacillus reuteri.

    PubMed Central

    Vescovo, M; Morelli, L; Bottazzi, V

    1982-01-01

    Sixteen strains of Lactobacillus reuteri and 20 strains of Lactobacillus acidophilus were tested for resistance to 22 antibiotics by using commercially available sensitivity disks. Evidence suggesting linkage of these resistances to plasmids was obtained by "curing" experiments with acridine dyes and high growth temperatures. Examination of plasmid patterns of agarose gel electrophoresis provided further evidence of loss in plasmid DNA under curing conditions in some of the strains examined. Images PMID:6798933

  13. Lactobacillus acidophilus ATCC 4356 inhibits biofilm formation by C. albicans and attenuates the experimental candidiasis in Galleria mellonella

    PubMed Central

    Vilela, Simone FG; Barbosa, Júnia O; Rossoni, Rodnei D; Santos, Jéssica D; Prata, Marcia CA; Anbinder, Ana Lia; Jorge, Antonio OC; Junqueira, Juliana C

    2015-01-01

    Probiotic strains of Lactobacillus have been studied for their inhibitory effects on Candida albicans. However, few studies have investigated the effect of these strains on biofilm formation, filamentation and C. albicans infection. The objective of this study was to evaluate the influence of Lactobacillus acidophilus ATCC 4356 on C. albicans ATCC 18804 using in vitro and in vivo models. In vitro analysis evaluated the effects of L. acidophilus on the biofilm formation and on the capacity of C. albicans filamentation. For in vivo study, Galleria mellonella was used as an infection model to evaluate the effects of L. acidophilus on candidiasis by survival analysis, quantification of C. albicans CFU/mL, and histological analysis. The direct effects of L. acidophilus cells on C. albicans, as well as the indirect effects using only a Lactobacillus culture filtrate, were evaluated in both tests. The in vitro results showed that both L. acidophilus cells and filtrate were able to inhibit C. albicans biofilm formation and filamentation. In the in vivo study, injection of L. acidophilus into G. mellonella larvae infected with C. albicans increased the survival of these animals. Furthermore, the number of C. albicans CFU/mL recovered from the larval hemolymph was lower in the group inoculated with L. acidophilus compared to the control group. In conclusion, L. acidophilus ATCC 4356 inhibited in vitro biofilm formation by C. albicans and protected G. mellonella against experimental candidiasis in vivo. PMID:25654408

  14. Lactobacillus acidophilus ATCC 4356 inhibits biofilm formation by C. albicans and attenuates the experimental candidiasis in Galleria mellonella.

    PubMed

    Vilela, Simone F G; Barbosa, Júnia O; Rossoni, Rodnei D; Santos, Jéssica D; Prata, Marcia C A; Anbinder, Ana Lia; Jorge, Antonio O C; Junqueira, Juliana C

    2015-01-01

    Probiotic strains of Lactobacillus have been studied for their inhibitory effects on Candida albicans. However, few studies have investigated the effect of these strains on biofilm formation, filamentation and C. albicans infection. The objective of this study was to evaluate the influence of Lactobacillus acidophilus ATCC 4356 on C. albicans ATCC 18804 using in vitro and in vivo models. In vitro analysis evaluated the effects of L. acidophilus on the biofilm formation and on the capacity of C. albicans filamentation. For in vivo study, Galleria mellonella was used as an infection model to evaluate the effects of L. acidophilus on candidiasis by survival analysis, quantification of C. albicans CFU/mL, and histological analysis. The direct effects of L. acidophilus cells on C. albicans, as well as the indirect effects using only a Lactobacillus culture filtrate, were evaluated in both tests. The in vitro results showed that both L. acidophilus cells and filtrate were able to inhibit C. albicans biofilm formation and filamentation. In the in vivo study, injection of L. acidophilus into G. mellonella larvae infected with C. albicans increased the survival of these animals. Furthermore, the number of C. albicans CFU/mL recovered from the larval hemolymph was lower in the group inoculated with L. acidophilus compared to the control group. In conclusion, L. acidophilus ATCC 4356 inhibited in vitro biofilm formation by C. albicans and protected G. mellonella against experimental candidiasis in vivo.

  15. Characterization of adhesive molecule with affinity to Caco-2 cells in Lactobacillus acidophilus by proteome analysis.

    PubMed

    Ashida, Nobuhisa; Yanagihara, Sae; Shinoda, Tadashi; Yamamoto, Naoyuki

    2011-10-01

    The adhesive activities of eight Lactobacillus acidophilus strains toward intestinal epithelial Caco-2 cells were studied to understand the probiotic characteristics of the L. acidophilus L-92 strain. Most of the strains, including L-92, showed high adhesive activity; CP23 showed the lowest adhesive activity. CP23 was selected for comparative analysis of cell wall-associated proteins versus the L-92 strain. Cell wall-associated proteins extracted from L-92 and CP23 were subjected to two-dimensional electrophoresis, and major spots observed in the former were compared to the corresponding spots in the latter. To understand the effects of key components of L-92 on its adhesion to Caco-2 cells, 18 spots with stronger signals in L-92 than those in CP23 were identified by a MALDI-TOF/TOF of Ultraflex analysis. Among the identified proteins of L-92, surface-layer protein A (SlpA) was considered strongly involved in adhesion in the eight L. acidophilus strains. To study the importance of SlpA in the adhesion of L. acidophilus, the amounts of SlpA proteins in LiCl extracts of the eight strains were compared by SDSpolyacrylamide gel electrophoresis. As a result, the adhesive abilities of L. acidophilus strains to Caco-2 cells correlated closely to the amount of SlpA in the cells and the productivity of IL-12, an inflammatory cytokine, in all eight strains. These results strongly suggested that SlpA in L. acidophilus might play a key role in its attachment to Caco-2 cells and in the release of IL-12 from dendritic cells.

  16. Effects of yogurt starter cultures on the survival of Lactobacillus acidophilus.

    PubMed

    Ng, Elizabeth W; Yeung, Marie; Tong, Phillip S

    2011-01-31

    Recognized to confer health benefits to consumers, probiotics such as Lactobacillus acidophilus are commonly incorporated into fermented dairy products worldwide; among which yogurt is a popular delivery vehicle. To materialize most of the putative health benefits associated with probiotics, an adequate amount of viable cells must be delivered at the time of consumption. However, the loss in their viabilities during refrigerated storage has been demonstrated previously. This study focused on the effects of yogurt starter cultures on the survival of five strains of L. acidophilus, with emphases on low pH and acid production. Differential survival behavior between L. acidophilus strains was further analyzed. To this end, viable cell counts of L. acidophilus were determined weekly during 4°C storage in various types of yogurts made with Streptococcus thermophilus alone, L. delbrueckii ssp. bulgaricus alone, both species of the starter cultures, or glucono-delta-lactone (GDL). All yogurt types, except for pasteurized yogurts, were co-fermented with L. acidophilus. Yogurt filtrate was analyzed for the presence of any inhibitory substance and for the amount of hydrogen peroxide. Multiplication of L. acidophilus was not affected by the starter cultures as all strains reached high level on day 0 of the storage period. Throughout the 28-day storage period, cell counts of L. acidophilus PIM703 and SBT2062 remained steady (~6 × 10(7)CFU/g) in yogurts made with both starter cultures, whereas those of ATCC 700396 and NCFM were reduced by a maximum of 3 and 4.6 logs, respectively. When starter cultures were replaced by GDL, all strains survived well, suggesting that a low pH was not a critical factor dictating their survival. In addition, the filtrate collected from yogurts made with starter cultures appeared to have higher inhibitory activities against L. acidophilus than that made with GDL. The presence of viable starter cultures was necessary to adversely affect the

  17. Serum cholesterol levels in axenic mice colonized with Enterococcus faecium and Lactobacillus acidophilus.

    PubMed

    Zacconi, C; Bottazzi, V; Rebecchi, A; Bosi, E; Sarra, P G; Tagliaferri, L

    1992-10-01

    Hypocholesterolemic effect was shown in axenic, mono, bicolonized and conventional mice: the effect was different depending on probiotic properties of intestinal microorganisms. Contamination by Enterococcus faecium CX determined the highest effect: haematic cholesterol level decrease was 16.9% in females and 7.8% in males. In mice contaminated by Lactobacillus acidophilus N5 the decrease of haematic cholesterol levels was less and not relevant in mice contaminated by conventional microflora. Enterococcus faecium CX and Lactobacillus acidophilus N5 strains were able to grow in presence of bile salts, to colonize intestinal tract, to survive at gastric conditions and to assimilate cholesterol (E. faecium more than L. acidophilus). The authors consider the possibility to associate probiotic strains with these characteristics for the health of consumers.

  18. Lactobacillus acidophilus binds to MUC3 component of cultured intestinal epithelial cells with highest affinity.

    PubMed

    Das, Jugal Kishore; Mahapatra, Rajani Kanta; Patro, Shubhransu; Goswami, Chandan; Suar, Mrutyunjay

    2016-04-01

    Lactobacillus strains have been shown to adhere to the mucosal components of intestinal epithelial cells. However, established in vitro adhesion assays have several drawbacks in assessing the adhesion of new Lactobacillus strains. The present study aimed to compare the adhesion of four different Lactobacillus strains and select the most adherent microbe, based on in silico approach supported by in vitro results. The mucus-binding proteins in Lactobacillus acidophilus, L. plantarum, L. brevis and L. fermentum were identified and their capacities to interact with intestinal mucin were compared by molecular docking analysis. Lactobacillus acidophilus had the maximal affinity of binding to mucin with predicted free energy of -6.066 kcal mol(-1) Further, in vitro experimental assay of adhesion was performed to validate the in silico results. The adhesion of L. acidophilus to mucous secreting colon epithelial HT-29 MTX cells was highest at 12%, and it formed biofilm with maximum depth (Z = 84 μm). Lactobacillus acidophilus was determined to be the most adherent strain in the study. All the Lactobacillus strains tested in this study, displayed maximum affinity of binding to MUC3 component of mucus as compared to other gastrointestinal mucins. These findings may have importance in the design of probiotics and health care management.

  19. The protective effect of recombinant FomA-expressing Lactobacillus acidophilus against periodontal infection.

    PubMed

    Ma, Li; Ding, Qinfeng; Feng, Xiping; Li, Fei

    2013-10-01

    A number of studies have shown that the outer membrane protein FomA found in Fusobacterium nucleatum demonstrates great potential as an immune target for combating periodontitis. Lactobacillus acidophilus is a useful antigen delivery vehicle for mucosal immunisation, and previous studies by our group have shown that L. acidophilus acts as a protective factor in periodontal health. In this study, making use of the immunogenicity of FomA and the probiotic properties of L. acidophilus, we constructed a recombinant form of L. acidophilus expressing the FomA protein and detected the FomA-specific IgG in the serum and sIgA in the saliva of mice through oral administration with the recombinant strains. When serum containing FomA-specific antibodies was incubated with the F. nucleatum in vitro, the number of Porphyromonas gingivalis cells that coaggregated with the F. nucleatum cells was significantly reduced. Furthermore, a mouse gum abscess model was successfully generated, and the range of gingival abscesses in the immune mice was relatively limited compared with the control group. The level of IL-1β in the serum and local gum tissues of the immune mice was consistently lower than in the control group. Our findings indicated that oral administration of the recombinant L. acidophilus reduced the risk of periodontal infection with P. gingivalis and F. nucleatum.

  20. In vitro evaluation of antibacterial activity of an herbal dentifrice against Streptococcus mutans and Lactobacillus acidophilus.

    PubMed

    Vyas, Yogesh Kumar; Bhatnagar, Maheep; Sharma, Kanika

    2008-01-01

    Antibacterial activity of a herbal dentifrice Arodent against Streptococcus mutans and Lactobacillus acidophilus was evaluated using Colgate as standard. Both bacterial strains were isolated from the oral cavity on selective media and identified by standard methods. The antibacterial activity was assayed by cup-well method. The bacterial lawn of facultative anaerobe S. mutans was established between two layers of agar under microaerophilic conditions. Five and a half millimeters and 10 mm zones of inhibition were produced by Arodent against S. mutans and L. acidophilus , respectively, under microaerophilic conditions. On the other hand, the standard dentifrice Colgate produced 5.83 mm and 10.17 mm zones of inhibition against S. mutans and L. acidophilus , respectively, under microaerophilic condition. The results suggest that Arodent is an effective antibacterial herbal dentifrice.

  1. Molecular Cloning, Expression of minD Gene from Lactobacillus acidophilus VTCC-B-871 and Analyses to Identify Lactobacillus rhamnosus PN04 from Vietnam Hottuynia cordata Thunb.

    PubMed

    Nguyen, Tu Hoang Khue; Doan, Vinh Thi Thanh; Ha, Ly Dieu; Nguyen, Huu Ngoc

    2013-12-01

    The minD gene encoding an inhibitor cell division MinD homolog from Lactobacillus acidophilus VTCC-B-871 was cloned. We showed that there were 97 % homology between minD genes of L. acidophilus VTCC-B-871 and Lactobacillus rhamnosus GG and Lactobacillus rhamnosus Lc705. Based on the analysis of the DNA sequence data from the L. rhamnosus genome project and sequenced minD gene of L. acidophilus VTCC-B-871, a pair of primers was designed to identified the different minD genes from L. acidophilus ATCC 4356, L. rhamnosus ATCC 11443. Besides, the polymerase chain reaction product of minD gene was also obtained in L. rhamnosus PN04, a strain was isolated from Vietnamese Hottuynia cordata Thunb. In addition, we performed a phylogenetic analysis of the deduced amino acid sequence of MinD homologs from L. acidophilus VTCC-B-871 with the other strains and compared the predicted three-dimension structure of L. acidophilus VTCC-B-871 MinD with Escherichia coli MinD, there are similarity that showed evolution of these strains. The overexpression of L. acidophilus VTCC-B-871 MinD in E. coli led to cell filamentation in IPTG and morphology changes in different sugar stresses, interestingly. The present study is the first report characterizing the Lactobacilus MinD homolog that will be useful in probiotic field.

  2. Anticholesteremic property of Lactobacillus acidophilus yogurt fed to mature boars.

    PubMed

    Danielson, A D; Peo, E R; Shahani, K M; Lewis, A J; Whalen, P J; Amer, M A

    1989-04-01

    Three strains of Lactobacilus acidophilus (LA) were isolated from the feces of mature boars that were not being fed antibiotics from the Nebraska Gene Pool (NGP). All three LA isolates were screened in vitro for anticholesteremic and antimicrobial activities. One strain, LA16, caused the greatest reduction in cholesterol and inhibited both Bacillus subtilis and Escherichia coli the most. LA16 was used to produce 16, 18.9-liter quantities of acidophilus yogurt (AY), over a period of 8 wk, for use as a feed ingredient in diets for the NGP boars. Colony forming units (cfu), pH, protein, energy, Ca and P were consistent across all 16 batches of yogurt. All of the 18 boars were fed a high-cholesterol diet for a period of 56 d at a rate of 2.268 kg/(hd.d) to furnish 6.661 g/(hd.d) of cholesterol. Nine of the boars then were fed 1.81 kg/(hd.d) of a second diet that was supplemented with .454 kg/(hd.d) of AY. The other nine boars were fed the original diet. Cholesterol intake was the same for the two dietary treatments. Blood samples were collected weekly from the brachial-jugular region and the sera were analyzed for lipids. Acidophilus yogurt reduced serum cholesterol (P less than .01) and low density lipoproteins (P less than .08), but it had no effect on serum triglycerides (P greater than .23) or on high density lipoproteins (P greater than .11).

  3. Development of a tiered multilocus sequence typing scheme for members of the Lactobacillus acidophilus complex.

    PubMed

    Ramachandran, Padmini; Lacher, David W; Pfeiler, Erika A; Elkins, Christopher A

    2013-12-01

    Members of the Lactobacillus acidophilus complex are associated with functional foods and dietary supplements because of purported health benefits they impart to the consumer. Many characteristics of these microorganisms are reported to be strain specific. Therefore, proper strain typing is essential for safety assessment and product labeling, and also for monitoring strain integrity for industrial production purposes. Fifty-two strains of the L. acidophilus complex (L. acidophilus, L. amylovorus, L. crispatus, L. gallinarum, L. gasseri, and L. johnsonii) were genotyped using two established methods and compared to a novel multilocus sequence typing (MLST) scheme. PCR restriction fragment length polymorphism (PCR-RFLP) analysis of the hsp60 gene with AluI and TaqI successfully clustered 51 of the 52 strains into the six species examined, but it lacked strain-level discrimination. Random amplified polymorphic DNA PCR (RAPD-PCR) targeting the M13 sequence resulted in highly discriminatory profiles but lacked reproducibility. In this study, an MLST scheme was developed using the conserved housekeeping genes fusA, gpmA, gyrA, gyrB, lepA, pyrG, and recA, which identified 40 sequence types that successfully clustered all of the strains into the six species. Analysis of the observed alleles suggests that nucleotide substitutions within five of the seven MLST loci have reached saturation, a finding that emphasizes the highly diverse nature of the L. acidophilus complex and our unconventional application of a typically intraspecies molecular typing tool. Our MLST results indicate that this method could be useful for characterization and strain discrimination of a multispecies complex, with the potential for taxonomic expansion to a broader collection of Lactobacillus species.

  4. Viability of probiotic (Bifidobacterium, Lactobacillus acidophilus and Lactobacillus casei) and nonprobiotic microflora in Argentinian Fresco cheese.

    PubMed

    Vinderola, C G; Prosello, W; Ghiberto, T D; Reinheimer, J A

    2000-09-01

    We evaluated the suitability of Argentinian Fresco cheese as a food carrier of probiotic cultures. We used cultures of Bifidobacterium bifidum (two strains), Bifidobacterium longum (two strains), Bifidobacterium sp. (one strain), Lactobacillus acidophilus (two strains), and Lactobacillus casei (two strains) in different combinations, as probiotic adjuncts. Probiotic, lactic starter (Lactococcus lactis and Streptococcus thermophilus), and contaminant (coliforms, yeasts, and molds) organisms were counted at 0, 30, and 60 d of refrigerated storage. Furthermore, the acid resistance of probiotic and starter bacteria was determined from hydrochloric solutions (pH 2 and 3) of Fresco cheese. The results showed that nine different combinations of bifidobacteria and L. acidophilus had a satisfactory viability (count decreases in 60 d <1 log order) in the cheese. Both combinations of bifidobacteria and L. casei cultures assayed also showed a satisfactory survival (counts decreased <1 log order for bifidobacteria but no decrease was detected for L. casei). On the other hand, the three combinations of bifidobacteria, L. acidophilus, and L. casei tested adapted well to the Fresco cheese environment. When a cheese homogenate at pH 3 was used to partially simulate the acidic conditions in the stomach, the probiotic cultures had an excellent ability to remain viable up to 3 h. At pH 2, the cell viability was more affected; B. bifidum was the most resistant organism. This study showed that the Argentinian Fresco cheese could be used as an adequate carrier of probiotic bacteria.

  5. Lactobacillus acidophilus-Rutin Interplay Investigated by Proteomics.

    PubMed

    Mazzeo, Maria Fiorella; Lippolis, Rosa; Sorrentino, Alida; Liberti, Sarah; Fragnito, Federica; Siciliano, Rosa Anna

    2015-01-01

    Dietary polyphenols are bioactive molecules that beneficially affect human health, due to their anti-oxidant, anti-inflammatory, cardio-protective and chemopreventive properties. They are absorbed in a very low percentage in the small intestine and reach intact the colon, where they are metabolized by the gut microbiota. Although it is well documented a key role of microbial metabolism in the absorption of polyphenols and modulation of their biological activity, molecular mechanisms at the basis of the bacteria-polyphenols interplay are still poorly understood. In this context, differential proteomics was applied to reveal adaptive response mechanisms that enabled a potential probiotic Lactobacillus acidophilus strain to survive in the presence of the dietary polyphenol rutin. The response to rutin mainly modulated the expression level of proteins involved in general stress response mechanisms and, in particular, induced the activation of protein quality control systems, and affected carbohydrate and amino acid metabolism, protein synthesis and cell wall integrity. Moreover, rutin triggered the expression of proteins involved in oxidation-reduction processes.This study provides a first general view of the impact of dietary polyphenols on metabolic and biological processes of L. acidophilus.

  6. Membrane filter method to study the effects of Lactobacillus acidophilus and Bifidobacterium longum on fecal microbiota.

    PubMed

    Shimizu, Hidenori; Benno, Yoshimi

    2015-11-01

    A large number of commensal bacteria inhabit the intestinal tract, and interbacterial communication among gut microbiota is thought to occur. In order to analyze symbiotic relationships between probiotic strains and the gut microbiota, a ring with a membrane filter fitted to the bottom was used for in vitro investigations. Test strains comprising probiotic nitto strains (Lactobacillus acidophilus NT and Bifidobacterium longum NT) and type strains (L. acidophilus JCM1132(T) and B. longum JCM1217(T) ) were obtained from diluted fecal samples using the membrane filter to simulate interbacterial communication. Bifidobacterium spp., Streptococcus pasteurianus, Collinsella aerofaciens, and Clostridium spp. were the most abundant gut bacteria detected before coculture with the test strains. Results of the coculture experiments indicated that the test strains significantly promote the growth of Ruminococcus gnavus, Ruminococcus torques, and Veillonella spp. and inhibit the growth of Sutterella wadsworthensis. Differences in the relative abundances of gut bacterial strains were furthermore observed after coculture of the fecal samples with each test strain. Bifidobacterium spp., which was detected as the dominant strain in the fecal samples, was found to be unaffected by coculture with the test strains. In the present study, interbacterial communication using bacterial metabolites between the test strains and the gut microbiota was demonstrated by the coculture technique. The detailed mechanisms and effects of the complex interbacterial communications that occur among the gut microbiota are, however, still unclear. Further investigation of these relationships by coculture of several fecal samples with probiotic strains is urgently required.

  7. Membrane filter method to study the effects of Lactobacillus acidophilus and Bifidobacterium longum on fecal microbiota

    PubMed Central

    Shimizu, Hidenori

    2015-01-01

    ABSTRACT A large number of commensal bacteria inhabit the intestinal tract, and interbacterial communication among gut microbiota is thought to occur. In order to analyze symbiotic relationships between probiotic strains and the gut microbiota, a ring with a membrane filter fitted to the bottom was used for in vitro investigations. Test strains comprising probiotic nitto strains (Lactobacillus acidophilus NT and Bifidobacterium longum NT) and type strains (L. acidophilus JCM1132T and B. longum JCM1217T) were obtained from diluted fecal samples using the membrane filter to simulate interbacterial communication. Bifidobacterium spp., Streptococcus pasteurianus, Collinsella aerofaciens, and Clostridium spp. were the most abundant gut bacteria detected before coculture with the test strains. Results of the coculture experiments indicated that the test strains significantly promote the growth of Ruminococcus gnavus, Ruminococcus torques, and Veillonella spp. and inhibit the growth of Sutterella wadsworthensis. Differences in the relative abundances of gut bacterial strains were furthermore observed after coculture of the fecal samples with each test strain. Bifidobacterium spp., which was detected as the dominant strain in the fecal samples, was found to be unaffected by coculture with the test strains. In the present study, interbacterial communication using bacterial metabolites between the test strains and the gut microbiota was demonstrated by the coculture technique. The detailed mechanisms and effects of the complex interbacterial communications that occur among the gut microbiota are, however, still unclear. Further investigation of these relationships by coculture of several fecal samples with probiotic strains is urgently required. PMID:26486646

  8. Functional Analysis of an S-Layer-Associated Fibronectin-Binding Protein in Lactobacillus acidophilus NCFM

    PubMed Central

    Hymes, Jeffrey P.; Johnson, Brant R.; Barrangou, Rodolphe

    2016-01-01

    Bacterial surface layers (S-layers) are crystalline arrays of self-assembling proteinaceous subunits called S-layer proteins (Slps) that comprise the outermost layer of the cell envelope. Many additional proteins that are associated with or embedded within the S-layer have been identified in Lactobacillus acidophilus NCFM, an S-layer-forming bacterium that is widely used in fermented dairy products and probiotic supplements. One putative S-layer-associated protein (SLAP), LBA0191, was predicted to mediate adhesion to fibronectin based on the in silico detection of a fibronectin-binding domain. Fibronectin is a major component of the extracellular matrix (ECM) of intestinal epithelial cells. Adhesion to intestinal epithelial cells is considered an important trait for probiotic microorganisms during transit and potential association with the intestinal mucosa. To investigate the functional role of LBA0191 (designated FbpB) in L. acidophilus NCFM, an fbpB-deficient strain was constructed. The L. acidophilus mutant with a deletion of fbpB lost the ability to adhere to mucin and fibronectin in vitro. Homologues of fbpB were identified in five additional putative S-layer-forming species, but no homologues were detected in species outside the L. acidophilus homology group. PMID:26921419

  9. Functional Analysis of an S-Layer-Associated Fibronectin-Binding Protein in Lactobacillus acidophilus NCFM.

    PubMed

    Hymes, Jeffrey P; Johnson, Brant R; Barrangou, Rodolphe; Klaenhammer, Todd R

    2016-05-01

    Bacterial surface layers (S-layers) are crystalline arrays of self-assembling proteinaceous subunits called S-layer proteins (Slps) that comprise the outermost layer of the cell envelope. Many additional proteins that are associated with or embedded within the S-layer have been identified in Lactobacillus acidophilus NCFM, an S-layer-forming bacterium that is widely used in fermented dairy products and probiotic supplements. One putative S-layer-associated protein (SLAP), LBA0191, was predicted to mediate adhesion to fibronectin based on the in silico detection of a fibronectin-binding domain. Fibronectin is a major component of the extracellular matrix (ECM) of intestinal epithelial cells. Adhesion to intestinal epithelial cells is considered an important trait for probiotic microorganisms during transit and potential association with the intestinal mucosa. To investigate the functional role of LBA0191 (designated FbpB) in L. acidophilus NCFM, an fbpB-deficient strain was constructed. The L. acidophilus mutant with a deletion off bpB lost the ability to adhere to mucin and fibronectin in vitro Homologues off bpB were identified in five additional putative S-layer-forming species, but no homologues were detected in species outside theL. acidophilus homology group.

  10. Aglycone Isoflavones and Exopolysaccharides Produced by Lactobacillus acidophilus in Fermented Soybean Paste

    PubMed Central

    Kim, Jin-Sun; Lee, Je-Hyuk; Surh, Jeonghee; Kang, Soon Ah; Jang, Ki-Hyo

    2016-01-01

    Bioconversion of aglycone-formed isoflavones from glycoside-formed isoflavones by commercial lactic acid bacteria in fermented soybean paste was evaluated. Enterococcus faecium KCTC 13410 showed the most resistant capacity and Lactobacillus acidophilus KCTC 3925 had a sensitive susceptibility at a high NaCl concentration (13.2%) in fermented soybean paste. Among the 5 strains tested, Lac. acidophilus KCTC 3925 showed the highest relative ratio of aglycone-formed isoflavones to total isoflavones in fermented soybean paste. Production of exopolysaccarides (EPS) by lactic acid bacteria was compared using de Man, Rogosa, and Sharpe medium containing 1% sucrose at 37°C for 48 h. Among the 5 lactic acid bacteria, Lac. acidophilus KCTC 3925 and Lactobacillus rhamnosus KCTC 3929 were investigated to produce EPS. Based on the results concerning growing susceptibility and conversion of aglycone-formed isoflavones/EPS production, it is anticipated that Lac. acidophilus KCTC 3925 may be used for preparation of Cheonggukjang, which contains relative low NaCl content. PMID:27390728

  11. Murein hydrolase activity of surface layer proteins from Lactobacillus acidophilus against Escherichia coli.

    PubMed

    Meng, Jun; Gao, Shu-Ming; Zhang, Qiu-Xiang; Lu, Rong-Rong

    2015-08-01

    The aim of this study was to investigate the murein hydrolase activities of the surface layer proteins (SLPs) from two strains of Lactobacillus acidophilus using zymography. The influence of these hydrolase activities on Escherichia coli ATCC 43893 was also evaluated by analysing their growth curve, cell morphology and physiological state. After the incubation of E. coli with SLPs, growth was inhibited, the number of viable cells was significantly reduced, examination by transmission electron microscopy showed that the cell wall was damaged and flow cytometry results indicated that the majority of the cells were sublethally injured. All of these results suggested that the SLPs of both L. acidophilus strains possessed murein hydrolase activities that were sublethal to E. coli cells.

  12. The quorum sensing luxS gene is induced in Lactobacillus acidophilus NCFM in response to Listeria monocytogenes.

    PubMed

    Moslehi-Jenabian, Saloomeh; Vogensen, Finn Kvist; Jespersen, Lene

    2011-10-03

    The luxS gene involved in quorum sensing has been shown to control different behaviour of probiotic lactobacilli. In this study we investigated if luxS in Lactobacillus acidophilus NCFM was up-regulated in response to Listeria monocytogenes EGD-e. The two bacterial strains were grown in mono- and co-culture and the growth of both bacteria and the transcriptional level of luxS in L. acidophilus cells were monitored. Contrary to L. acidophilus, the growth of L. monocytogenes was significantly affected by co-cultivation. Transcriptional analysis showed that the expression of luxS increased during exponential growth in L. acidophilus cells with the highest level in the late-exponential growth phase, decreasing in the stationary phase. Following co-cultivation with L. monocytogenes, the transcriptional level of luxS increased significantly in mid-exponential growing cells of L. acidophilus after incubation with viable L. monocytogenes cells and by addition of cell-free culture supernatant of L. monocytogenes, whereas incubation with heat killed cells of L. monocytogenes had no effect on the transcriptional level. This could indicate that the up-regulation of luxS is due to a response to a secreted compound produced by L. monocytogenes cells.

  13. Lactobacillus acidophilus induces virus immune defence genes in murine dendritic cells by a Toll-like receptor-2-dependent mechanism.

    PubMed

    Weiss, Gudrun; Rasmussen, Simon; Zeuthen, Louise Hjerrild; Nielsen, Birgit Nøhr; Jarmer, Hanne; Jespersen, Lene; Frøkiaer, Hanne

    2010-10-01

    Lactobacilli are probiotics that, among other health-promoting effects, have been ascribed immunostimulating and virus-preventive properties. Certain Lactobacillus spp. have been shown to possess strong interleukin-12 (IL-12) -inducing properties. As IL-12 production depends on the up-regulation of type I interferons (IFNs), we hypothesized that the strong IL-12-inducing capacity of Lactobacillus acidophilus NCFM in murine bone-marrow-derived dendritic cells (DCs) is caused by an up-regulation of IFN-β, which subsequently induces IL-12 and the double-stranded RNA binding Toll-like receptor-3 (TLR-3). The expression of the genes encoding IFN-β, TLR-3, IL-12 and IL-10 in DCs upon stimulation with L. acidophilus NCFM was determined. Lactobacillus acidophilus NCFM induced a much stronger expression of Ifn-β, Il-12 and Il-10 compared with the synthetic double-stranded RNA ligand Poly I:C, whereas the levels of expressed Tlr-3 were similar. Whole genome microarray gene expression analysis revealed that other genes related to viral defence were significantly up-regulated and among the strongest induced genes in DCs stimulated with L. acidophilus NCFM. The ability to induce IFN-β was also detected in another L. acidophilus strain (X37), but was not a property of other probiotic strains tested, i.e. Bifidobacterium bifidum Z9 and Escherichia coli Nissle 1917. The IFN-β expression was markedly reduced in TLR-2(-/-) DCs, dependent on endocytosis, and the major cause of the induction of Il-12 and Tlr-3 in DCs stimulated with L. acidophilus NCFM. Collectively, our results reveal that certain lactobacilli trigger the expression of viral defence genes in DCs in a TLR-2 manner dependent on IFN-β.

  14. Probiotic Bovamine fine-tunes the ruminal microbiome for enhanced fermentation and immunity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We evaluated the effect of Bovamine, Lactobacillus acidophilus strain NP51 and Propionibacterium freudenreichii strain strain NP24, feeding on the microbial composition of the digestive system microbiota of dairy cattle during late lactation (average DIM = 202 days on time 0). To examine the underly...

  15. Sulfur Metabolism Pathways in Sulfobacillus acidophilus TPY, A Gram-Positive Moderate Thermoacidophile from a Hydrothermal Vent.

    PubMed

    Guo, Wenbin; Zhang, Huijun; Zhou, Wengen; Wang, Yuguang; Zhou, Hongbo; Chen, Xinhua

    2016-01-01

    Sulfobacillus acidophilus TPY, isolated from a hydrothermal vent in the Pacific Ocean, is a moderately thermoacidophilic Gram-positive bacterium that can oxidize ferrous iron or sulfur compounds to obtain energy. In this study, comparative transcriptomic analyses of S. acidophilus TPY were performed under different redox conditions. Based on these results, pathways involved in sulfur metabolism were proposed. Additional evidence was obtained by analyzing mRNA abundance of selected genes involved in the sulfur metabolism of sulfur oxygenase reductase (SOR)-overexpressed S. acidophilus TPY recombinant under different redox conditions. Comparative transcriptomic analyses of S. acidophilus TPY cultured in the presence of ferrous sulfate (FeSO4) or elemental sulfur (S(0)) were employed to detect differentially transcribed genes and operons involved in sulfur metabolism. The mRNA abundances of genes involved in sulfur metabolism decreased in cultures containing elemental sulfur, as opposed to cultures in which FeSO4 was present where an increase in the expression of sulfur metabolism genes, particularly sulfite reductase (SiR) involved in the dissimilatory sulfate reduction, was observed. SOR, whose mRNA abundance increased in S(0) culture, may play an important role in the initial sulfur oxidation. In order to confirm the pathways, SOR overexpression in S. acidophilus TPY and subsequent mRNA abundance analysis of sulfur metabolism-related genes were carried out. Conjugation-based transformation of pTrc99A derived plasmid from heterotrophic E. coli to facultative autotrophic S. acidophilus TPY was developed in this study. Transconjugation between E. coli and S. acidophilus was performed on modified solid 2:2 medium at pH 4.8 and 37°C for 72 h. The SOR-overexpressed recombinant S. acidophilus TPY-SOR had a [Formula: see text]-accumulation increase, higher oxidation/ reduction potentials (ORPs) and lower pH compared with the wild type strain in the late growth stage of S

  16. Sulfur Metabolism Pathways in Sulfobacillus acidophilus TPY, A Gram-Positive Moderate Thermoacidophile from a Hydrothermal Vent

    PubMed Central

    Guo, Wenbin; Zhang, Huijun; Zhou, Wengen; Wang, Yuguang; Zhou, Hongbo; Chen, Xinhua

    2016-01-01

    Sulfobacillus acidophilus TPY, isolated from a hydrothermal vent in the Pacific Ocean, is a moderately thermoacidophilic Gram-positive bacterium that can oxidize ferrous iron or sulfur compounds to obtain energy. In this study, comparative transcriptomic analyses of S. acidophilus TPY were performed under different redox conditions. Based on these results, pathways involved in sulfur metabolism were proposed. Additional evidence was obtained by analyzing mRNA abundance of selected genes involved in the sulfur metabolism of sulfur oxygenase reductase (SOR)-overexpressed S. acidophilus TPY recombinant under different redox conditions. Comparative transcriptomic analyses of S. acidophilus TPY cultured in the presence of ferrous sulfate (FeSO4) or elemental sulfur (S0) were employed to detect differentially transcribed genes and operons involved in sulfur metabolism. The mRNA abundances of genes involved in sulfur metabolism decreased in cultures containing elemental sulfur, as opposed to cultures in which FeSO4 was present where an increase in the expression of sulfur metabolism genes, particularly sulfite reductase (SiR) involved in the dissimilatory sulfate reduction, was observed. SOR, whose mRNA abundance increased in S0 culture, may play an important role in the initial sulfur oxidation. In order to confirm the pathways, SOR overexpression in S. acidophilus TPY and subsequent mRNA abundance analysis of sulfur metabolism-related genes were carried out. Conjugation-based transformation of pTrc99A derived plasmid from heterotrophic E. coli to facultative autotrophic S. acidophilus TPY was developed in this study. Transconjugation between E. coli and S. acidophilus was performed on modified solid 2:2 medium at pH 4.8 and 37°C for 72 h. The SOR-overexpressed recombinant S. acidophilus TPY-SOR had a SO42−-accumulation increase, higher oxidation/ reduction potentials (ORPs) and lower pH compared with the wild type strain in the late growth stage of S0 culture

  17. Chromosomal-gene-mediated inhibition of intestinal and foodborne pathogens by Lactobacillus acidophilus AA11.

    PubMed

    Abo-Amer, Aly E

    2006-01-01

    Approximately 63 strains of Lactobacillus acidophilus were isolated from Egyptian home-made cheese and examined for production of antagonism. Only eight strains demonstrated inhibitory activity against spoilage microorganisms (i.e. Staphylococcus aureus and Bacillus cereus) and pathogens (i.e. E. coli, Salmonella sp. and Shigella sp.). Lactobacillus acidophilus AA11 produced a more antimicrobial activity with a wide range of inhibition. The agent AA11 was sensitive to proteolytic enzymes and retained full activity after 30 min at 100 degrees C. Activity against sensitive cells was bactericidal but not bacteriolytic. The compound was produced during growth phase and can be extracted from the culture supernatant fluids with n-Butanol. 12 % SDS-PAGE analysis of 40% ammonium sulphate precipitated agent showed two peptides with molecular weights of approximately 36 kDa and approximately 29 kDa. No plasmid was identified in Lactobacillus acidophilus AA11 indicating that the genes encoding the inhibitory agent located on the chromosome. These characteristics identify the inhibitory substance as a bacteriocin, designated acidocin AA11 and confer the agent an application potential as a biopreservative.

  18. Effect of exopolysaccharides on the hydrolysis of beta-lactoglobulin by Lactobacillus acidophilus CRL 636 in an in vitro gastric/pancreatic system.

    PubMed

    Pescuma, Micaela; Hébert, Elvira María; Dalgalarrondo, Michèle; Haertlé, Thomas; Mozzi, Fernanda; Chobert, Jean-Marc; Font de Valdez, Graciela

    2009-06-24

    An analysis of the peptides generated by hydrolysis of BLG by nonproliferating cells of the strain Lactobacillus acidophilus CRL 636 was carried out. The effect of polysaccharides (pectin, and two EPS synthesized by two Streptococcus thermophilus strains, EPS1190 and EPS804) on BLG digestibility using an in vitro gastric/pancreatic system was analyzed. Polysaccharides are commonly used in the dairy industry to improve food texture; these hydrocolloids may interact with proteins, affecting their digestibility. Nonproliferating cells of Lb. acidophilus CRL 636 were able to hydrolyze 52% of BLG. Twenty-six resulting peptides with molecular masses in the range 544-4119 Da were identified by LC-MS/MS. These peptides resulted mostly from the hydrolysis of the more accessible N-terminal part of BLG. Degradation of BLG by pepsin was poor (8%). When BLG was previously hydrolyzed by Lb. acidophilus CRL 636, peptic hydrolysis was of 54.8%, while when pectin and EPS1190 were added, hydrolysis was higher (58.2 and 57.2%, respectively). Peptides crossing 8 kDa dialysis membranes after trypsin/chymotrypsin hydrolysis were analyzed by HPSEC. The produced peptides were smaller when BLG was hydrolyzed previously by the Lb. acidophilus strain. Moreover, in the presence of pectin, the amount of the larger peptide (3.5 kDa) observed in the size exclusion chromatograms was considerably decreased. Our studies showed that prehydrolysis of BLG by Lb. acidophilus CRL 636 had a positive influence on BLG digestibility and that polysaccharides may change the peptide profile yielded by trypsin/chymotrypsin hydrolysis, releasing smaller size peptides, which are known to be less immune-reactive. Moreover, Lb. acidophilus CRL 636 was able to hydrolyze the main epitopes (41-60, 102-124, and 149-162) of BLG, reducing its allergenic content.

  19. Construction and immunogenicity of the recombinant Lactobacillus acidophilus pMG36e-E0-LA-5 of bovine viral diarrhea virus.

    PubMed

    Zhao, Yuelan; Jiang, Lufeng; Liu, Teng; Wang, Min; Cao, Wenbo; Bao, Yongzhan; Qin, Jianhua

    2015-12-01

    Bovine viral diarrhea/mucosal disease (BVD/MD) is an infectious disease of cattle with a worldwide distribution, creating a substantial economic impact. It is caused by bovine viral diarrhea virus (BVDV). This research was conducted to construct the recombinant Lactobacillus acidophilus (L. acidophilus) pMG36e-E0-LA-5 of BVDV E0 gene and to test its immunogenicity and protective efficacy against BVDV infection in the mice model. The BVDV E0 gene was sub-cloned into the expression vector and then transformed into the L. acidophilus LA-5 strain by electroporation. The recombinant L. acidophilus pMG36e-E0-LA-5 was confirmed by the sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and Western blotting. The mice were immunized orally with the recombinant L. acidophilus pMG36e-E0-LA-5. The serum IgG antibody and fecal sIgA antibody responses, expression levels of interleukin (IL)-12 (IL-12) and interferon gamma (IFN-γ) were detected respectively. On the 7th day after the last-immunization, the mice were inoculated with BVDV to evaluate the protective efficiency of the recombinant L. acidophilus pMG36e-E0-LA-5. The results showed that the expressed products protein E0 in the L. acidophilus LA-5 resulted in single band of 27kDa by SDS-PAGE and its strong reactivity with BVDV antibody was confirmed by Western blotting. The IgG and sIgA antibodies responses, IL-12 and IFN-γ expression levels in the vaccinated mice with recombinant L. acidophilus pMG36e-E0-LA-5 were significantly higher than those in the control mice. The protective rate of the vaccinated mice against BVDV increased significantly, and a 90.00% protection rate in virulent challenge was observed. These results indicated that the recombinant L. acidophilus pMG36e-E0-LA-5 strain was successfully constructed and it could effectively improve the immune response in mice and might provide protection against BVDV.

  20. Effect of Low Shear Modeled Microgravity (LSMMG) on the Probiotic Lactobacillus Acidophilus ATCC 4356

    NASA Technical Reports Server (NTRS)

    Stahl, S.; Voorhies, A.; Lorenzi, H.; Castro-Wallace, S.; Douglas, G.

    2016-01-01

    The introduction of generally recognized as safe (GRAS) probiotic microbes into the spaceflight food system has the potential for use as a safe, non-invasive, daily countermeasure to crew microbiome and immune dysregulation. However, the microgravity effects on the stress tolerances and genetic expression of probiotic bacteria must be determined to confirm translation of strain benefits and to identify potential for optimization of growth, survival, and strain selection for spaceflight. The work presented here demonstrates the translation of characteristics of a GRAS probiotic bacteria to a microgravity analog environment. Lactobacillus acidophilus ATCC 4356 was grown in the low shear modeled microgravity (LSMMG) orientation and the control orientation in the rotating wall vessel (RWV) to determine the effect of LSMMG on the growth, survival through stress challenge, and gene expression of the strain. No differences were observed between the LSMMG and control grown L. acidophilus, suggesting that the strain will behave similarly in spaceflight and may be expected to confer Earth-based benefits.

  1. Modification of immune responses and digestive system microbiota of lactating dairy cows by feeding Bovamine(R)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We evaluated the immune modulatory effects as well as effects on productivity of Bovamine® (Lactobacillus acidophilus strain NP51 and Probionibacterium freudenreichii) fed to Holstein and Jersey dairy cows during late lactation (average DIM = 202.44 days on wk-0). Cows were randomized to treatment g...

  2. Modification of digestive system microbiome of lactating dairy cows by feeding Bovamine: effect on ruminal fermentation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We evaluated the immune modulatory effects as well as effects on productivity of Bovamine® (Lactobacillus acidophilus strain NP51 and Probionibacterium freudenreichii) on the digestive system microbiome of dairy cattle during late lactation (average DIM = 202). To unveil the underlying mechanisms, ...

  3. Th1 Cytokine Production Induced by Lactobacillus acidophilus in BALB/c Mice Bearing Transplanted Breast Tumor

    PubMed Central

    Imani Fooladi, Abbas Ali; Yazdi, Mohammad Hossein; Pourmand, Mohammad Reza; Mirshafiey, Abbas; Hassan, Zuhair Mohammad; Azizi, Taghi; Mahdavi, Mehdi; Soltan Dallal, Mohammad Mehdi

    2015-01-01

    Background: The immunomodulative effects of Lactic Acid Bacteria as probiotics have been already demonstrated. Objectives: The current study aimed to evaluate the effect of oral administration of Lactobacillus acidophilus on the immune responses and patterns of cytokine production in the BALB/c mice bearing breast cancer. Materials and Methods: The current study used thirty inbred BALB/c mice, six- to eight-week-old; they were divided into two groups of 15 each. One group was used as control in each assay. The L. acidophilus (ATCC4356) used in the study was inoculated in MRS broth and cultivated overnight at 37°C under anaerobic conditions, then collected by centrifugation, and re-suspended in Phosphate-buffered Saline (PBS) media. After preparation of the proper amount of the suspension, it was orally administered to the mice via gavage and the control mice received an equal volume of PBS in the same manner. Results: The results showed that oral administration of L. acidophilus as a potent immunostimulator agent could motivate the proliferation of immune cells. Moreover, it could increase the production of IFN-γ and decrease the production of IL-4, known as Th2 cytokines, in the spleen cell culture. The results showed that the survival time of the L. acidophilus administered mice significantly increased in comparison to that of the control mice. Conclusions: The current study findings suggested that L. acidophilus can promote immune responses with Th1 bias and may increase the antitumor response. Further, the consumption of this probiotic strain may help to manage the immune response in tumor condition, but more studies are needed to investigate the other mechanisms of this effect. PMID:26034546

  4. Prebiotic Effects of Agave salmiana Fructans in Lactobacillus acidophilus and Bifidobacterium lactis Cultures.

    PubMed

    Castro-Zavala, Adriana; Juárez-Flores, Bertha I; Pinos-Rodríguez, Juan M; Delgado-Portales, Rosa E; Aguirre-Rivera, Juan R; Alcocer-Gouyonnet, Francisco

    2015-11-01

    Agave salmiana is a fructan rich species that is widely distributed in Mexico. The aim of this investigation was to extract the fructans of A. salmiana and evaluate their prebiotic effect in 48 hours in vitro cultures of Bifidobacterium lactis and Lactobacillus acidophilus and to compare this effect with other available fructan sources. A significant difference in pH, optical density and biomass was found in the cultures depending on the source of fructans and the type of bacteria. It was possible to determine a dose-response effect of the A. salmiana fructans and the growth of the studied strains.

  5. Simulated microgravity affects some biological characteristics of Lactobacillus acidophilus.

    PubMed

    Shao, Dongyan; Yao, Linbo; Riaz, Muhammad Shahid; Zhu, Jing; Shi, Junling; Jin, Mingliang; Huang, Qingsheng; Yang, Hui

    2017-04-01

    The effects of weightlessness on enteric microorganisms have been extensively studied, but have mainly been focused on pathogens. As a major component of the microbiome of the human intestinal tract, probiotics are important to keep the host healthy. Accordingly, understanding their changes under weightlessness conditions has substantial value. This study was carried out to investigate the characteristics of Lactobacillus acidophilus, a typical probiotic for humans, under simulated microgravity (SMG) conditions. The results revealed that SMG had no significant impact on the morphology of L. acidophilus, but markedly shortened its lag phase, enhanced its growth rate, acid tolerance ability up to pH < 2.5, and the bile resistance at the bile concentration of <0.05%. SMG also decreased the sensitivity of L. acidophilus to cefalexin, sulfur gentamicin, and sodium penicillin. No obvious effect of SMG was observed on the adhesion ability of L. acidophilus to Caco-2 cells. Moreover, after SMG treatment, both the culture of L. acidophilus and its liquid phase exhibited higher antibacterial activity against S. typhimurium and S. aureus in a time-dependent manner. The SMG treatment also increased the in vitro cholesterol-lowering ability of L. acidophilus by regulating the expression of the key cholesterol metabolism genes CYP7A1, ABCB11, LDLR, and HMGCR in the HepG2 cell line. Thus, the SMG treatment did have considerable influence on some biological activities and characteristics of L. acidophilus related to human health. These findings provided valuable information for understanding the influence of probiotics on human health under simulated microgravity conditions, at least.

  6. Use of PCR primers and probes based on the 23S rRNA and internal transcription spacer (ITS) gene sequence for the detection and enumerization of Lactobacillus acidophilus and Lactobacillus plantarum in feed supplements.

    PubMed

    Tsai, Cheng-Chih; Lai, Chieh-Hsien; Yu, Bi; Tsen, Hau-Yang

    2010-06-01

    Novel polymerase chain reaction (PCR) primers designed from the 16S-23S internal transcription spacer (ITS) rRNA and 23S rRNA genes, respectively, were used for the specific detection of Lactobacillus acidophilus and Lactobacillus plantarum. Molecular weights of the PCR products were 221 and 599 bp, respectively. Strains of L. acidophilus and L. plantarum obtained from the culture center, dairy products, infant stool and other samples, could be identified with these PCR primers. DNAs from other lactic acid bacteria (LAB) species including strains of Lactobacillus pentosus which was closely related to L. plantarum, and bacteria species other than LAB, would not generate the false positive results. When this PCR primer set was used for the detection of L. acidophilus and L. plantarum in feed supplement or feed starter samples, reliable results were obtained. Furthermore, when these L. acidophilus or L. plantarum specific primers were used as DNA probes for the colony hybridization of L. acidophilus and L. plantarum, the viable cells of these LAB species in culture and feed supplements or starter products could be identified and enumerized. The method described here thus offers a rapid and economic way to inspect and assure the quality of the feed supplements or fermentation starters.

  7. The substitution of a traditional starter culture in mutton fermented sausages by Lactobacillus acidophilus and Bifidobacterium animalis.

    PubMed

    Holko, I; Hrabě, J; Šalaková, A; Rada, V

    2013-07-01

    Common starter cultures used in fermented mutton sausages were substituted by probiotic strains of Lactobacillus acidophilus CCDM 476 and Bifidobacterium animalis 241a. Technological properties of the traditional and the probiotic sausages were compared. The potential probiotic effect was evaluated by enumeration of bifidobacteria and lactobacilli in stool samples of 15 volunteers before and after a 14-day consumption period. The numbers of lactobacilli (10(7) cfu/g) and bifidobacteria (10(3) cfu/g) in the final product did not affect the technological properties. The use of L. acidophilus as a starter culture was found more beneficial than the use of B. animalis. Even after 60 days of storage, high counts of L. acidophilus (10(6) cfu/g) were detected; on the other hand, the counts of B. animalis were under the detection limit. Regarding sensory properties, the probiotic products showed better texture, and, curiously, a reduction of the typical smell of mutton. The numbers of lactobacilli in stool samples increased significantly after the consumption of the probiotic sausages.

  8. Yield improvement of exopolysaccharides by screening of the Lactobacillus acidophilus ATCC and optimization of the fermentation and extraction conditions

    PubMed Central

    Liu, Qi; Huang, Xingjian; Yang, Dengxiang; Si, Tianlei; Pan, Siyi; Yang, Fang

    2016-01-01

    Exopolysacharides (EPS) produced by Lactobacillus acidophilus play an important role in food processing with its well-recognized antioxidant activity. In this study, a L. acidophilus mutant strain with high-yielding EPS (2.92±0.05 g/L) was screened by chemical mutation (0.2 % diethyl sulfate). Plackett-Burman (PB) design and response surface methodology (RSM) were applied to optimize the EPS fermentation parameters and central composite design (CCD) was used to optimize the EPS extraction parameters. A strain with high-yielding EPS was screened. It was revealed that three parameters (Tween 80, dipotassium hydrogen phosphate and trisodium citrate) had significant influence (P < 0.05) on the EPS yield. The optimal culture conditions for EPS production were: Tween 80 0.6 mL, dipotassium hydrogen phosphate 3.6 g and trisodium citrate 4.1 g (with culture volume of 1 L). In these conditions, the maximum EPS yield was 3.96±0.08 g/L. The optimal extraction conditions analyzed by CCD were: alcohol concentration 70 %, the ratio of material to liquid (M/L ratio) 1:3.6 and the extraction time 31 h. In these conditions, the maximum EPS extraction yield was 1.48±0.23 g/L. It was confirmed by the verification experiments that the EPS yield from L. acidophilus mutant strains reached 5.12±0.73 g/L under the optimized fermentation and extraction conditions, which was 3.8 times higher than that of the control (1.05±0.06 g/L). The results indicated that the strain screening with high-yielding EPS was successful and the optimized fermentation and extraction conditions significantly enhanced EPS yield. It was efficient and industrially promising. PMID:27103893

  9. Antigenic proteins of Lactobacillus acidophilus that are recognised by serum IgG antibodies in children with type 1 diabetes and coeliac disease.

    PubMed

    Prangli, Anna-Liisa; Utt, Meeme; Talja, Ija; Sepp, Epp; Mikelsaar, Marika; Rajasalu, Tarvo; Uibo, Oivi; Tillmann, Vallo; Uibo, Raivo

    2010-06-01

    Immune responses to lactobacilli have been so far insufficiently investigated in patients with autoimmune diseases. We used whole-cell lysate of an indigenous Lactobacillus acidophilus strain isolated from an Estonian child to study serum IgG antibodies in children groups with type 1 diabetes [insulin dependent diabetes mellitus (IDDM)] (n = 21, age 4-18 yr) and with acute coeliac disease (CD) (n = 20, age 0.6-15 yr) and to compare the results with the controls (n = 24, age 2-17 yr). We found that our developed 1-D immunoblot assay readily enables to reveal antibodies against 28 L. acidophilus antigenic proteins in patients' and controls' sera. As verified by immunoproteomics analysis with 2-D and LC ESI-MS/MS the antigens of L. acidophilus were mainly common cytoplasmic proteins GroEL (HSP60), enolase, transcription factor EF-Ts and EF-Tu. However, in addition we identified formyl-CoA transferase being target for antibodies in every tested IDDM patients' serum. We have characterized for the first time the antigenic profile of L. acidophilus whole-cell lysate using sera from children with IDDM, CD, and controls. The different prevalence of reactions against tested antigens in patients and controls sera may indicate significant differences in immune system and commensal bacteria cross-talk in these groups.

  10. Enteric coating of granules containing the probiotic Lactobacillus acidophilus.

    PubMed

    Pyar, Hassan; Peh, Kok-Khiang

    2014-06-01

    In the present study, a capsule formulation composed of enteric coated granules of Lactobacillus acidophilus ATCC 4962 was developed using Eudragit L30D-55 as enteric polymer. Optimization of the capsule formulation was achieved with a maximum viable cell count after 2 h of incubation in acid medium and disintegration time of 1 h in buffer pH 6.8. The amount of Eudragit L30D-55 in the capsules correlated with gastric juice resistance. The best protective qualities against artificial gastric juice were observed when capsules were prepared from granules composed of L. acidophilus, corn starch, lactose monohydrate, polyvinylpyrrolidone and coated with 12.5 % (m/V) of Eudragit L30D-55. Capsule formulation of L. acidophilus in edible broth medium suspension serves as a cheap alternative to the expensive freeze-drying procedure for preparing L. acidophilus. In addition, the enteric coating using Eudragit L30D-55 could protect probiotics from the acidic gastric environment and enhance the bioactivity of probiotics along with replacement of pathogenic microbes in human intestine.

  11. Multivalent Chromosomal Expression of the Clostridium botulinum Serotype A Neurotoxin Heavy-Chain Antigen and the Bacillus anthracis Protective Antigen in Lactobacillus acidophilus

    PubMed Central

    Klaenhammer, Todd R.

    2016-01-01

    ABSTRACT Clostridium botulinum and Bacillus anthracis produce potent toxins that cause severe disease in humans. New and improved vaccines are needed for both of these pathogens. For mucosal vaccine delivery using lactic acid bacteria, chromosomal expression of antigens is preferred over plasmid-based expression systems, as chromosomal expression circumvents plasmid instability and the need for antibiotic pressure. In this study, we constructed three strains of Lactobacillus acidophilus NCFM expressing from the chromosome (i) the nontoxic host receptor-binding domain of the heavy chain of Clostridium botulinum serotype A neurotoxin (BoNT/A-Hc), (ii) the anthrax protective antigen (PA), and (iii) both the BoNT/A-Hc and the PA. The BoNT/A-Hc vaccine cassette was engineered to contain the signal peptide from the S-layer protein A from L. acidophilus and a dendritic-cell-targeting peptide. A chromosomal region downstream of lba0889 carrying a highly expressed enolase gene was selected for insertion of the vaccine cassettes. Western blot analysis confirmed the heterologous expression of the two antigens from plasmid and chromosome locations. Stability assays demonstrated loss of the vaccine cassettes from expression plasmids without antibiotic maintenance. RNA sequencing showed high expression of each antigen and that insertion of the vaccine cassettes had little to no effect on the transcription of other genes in the chromosome. This study demonstrated that chromosomal integrative recombinant strains are promising vaccine delivery vehicles when targeted into high-expression chromosomal regions. Levels of expression match high-copy-number plasmids and eliminate the requirement for antibiotic selective maintenance of recombinant plasmids. IMPORTANCE Clostridium botulinum and Bacillus anthracis produce potent neurotoxins that pose a biochemical warfare concern; therefore, effective vaccines against these bacteria are required. Chromosomal expression of antigens is

  12. Some probiotic and antibacterial properties of Lactobacillus acidophilus cultured from dahi a native milk product.

    PubMed

    Mahmood, Talat; Masud, Tariq; Sohail, Asma

    2014-08-01

    In this study, different strains of Lactobacillus acidophilus from dahi were analyzed for certain probiotic and antibacterial properties. Initially, these strains were confirmed by the amplification of 16S rRNA regions and then screened for antibacterial activities against food borne pathogens. The phenotypic relationship between apparent antibacterial activity and cell wall proteins were established by cluster analysis. It was observed that those strains, which have prominent bands having size 22-25 kDa possess antibacterial activity. On the basis of wide spectrum of killing pattern, a strain LA06FT was further characterized that showed no change in its behavior when subjected to the antibiotic protected environment and grow well in acid-bile conditions. The bacteriocin produced by this strain has specific antibacterial activity of 5369.13 AU mg(-1). It remained stable at 60-90 °C and pH range of 4.5-6.5 while proteolytic enzymes inactivate the bacteriocin that confirm its proteinic nature having molecular weight of ≤8.5 kDa.

  13. Characterization of the temperate bacteriophage phi adh and plasmid transduction in Lactobacillus acidophilus ADH.

    PubMed

    Raya, R R; Kleeman, E G; Luchansky, J B; Klaenhammer, T R

    1989-09-01

    Lactobacillus acidophilus ADH is lysogenic and harbors an inducible prophage, phi adh. Bacteriophage were detected in cell lysates induced by treatment with mitomycin C or UV light. Electron microscopy of lysates revealed phage particles with a hexagonal head (62 nm) and a long, noncontractile, flexible tail (398 nm) ending in at last five short fibers. Phage phi adh was classified within Bradley's B1 phage group and the Siphoviridae family. The phi adh genome is a linear double-stranded DNA molecule of 41.7 kilobase pairs with cohesive ends: a physical map of the phi adh genome was constructed. A prophage-cured derivative of strain ADH, designated NCK102, was isolated from cells that survived UV exposure. NCK102 did not exhibit mitomycin C-induced lysis, but broth cultures lysed upon addition of phage. Phage phi adh produced clear plaques on NCK102 in media containing 10 mM CaCl2 at pH values between 5.2 and 5.5. A relysogenized derivative (NCK103) of NCK102 was isolated that exhibited mitomycin C-induced lysis and superinfection immunity to phage phi adh. Hybridization experiments showed that the phi adh genome was present in the ADH and NCK103 chromosomes, but absent in NCK102. These results demonstrated classic lytic and lysogenic cycles of replication for the temperate phage phi adh induced from L. acidophilus ADH. Phage phi adh also mediates transduction of plasmid DNA. Transductants of strain ADH containing pC194, pGK12, pGB354, and pVA797 were detected at frequencies in the range of 3.6 x 10(-8) to 8.3 x 10(-10) per PFU. Rearrangements or deletions were not detected in these plasmids as a consequence of transduction. This is the first description of plasmid transduction in the genus Lactobacillus.

  14. Fermentation of Dietetic Fiber from Green Bean and Prickly Pear Shell by Pure and Mixture Culture of Lactobacillus acidophilus LA-5 and Bifidobacterium bifidum 450B.

    PubMed

    Mora-Cura, Y N; Meléndez-Rentería, N P; Delgado-García, M; Contreras-Esquivel, J C; Morlett-Chávez, J A; Aguilar, C N; Rodríguez-Herrera, R

    2017-03-23

    The aim of this study was to evaluate the fermentation of dietary fiber from green bean (Phaseolus vulgaris) and prickly pear shell (Opuntia ficus-indica) by Lactobacillus acidophilus LA-5 and Bifidobacterium bifidum 450B growing as mono-culture and co-culture, the fermentation products, and proteins expressed during this process. The analysis of the fermentation profile showed a major growth of bacteria in the culture media of each dietary fiber supplemented with glucose, and particularly B. bifidum 450B at 48 h showed the highest growth. In the case of the co-culture, the growth was lower indicating the possible negative interaction between L. acidophilus LA-5 and B. bifidum 450B and may be due to the less amount of carbohydrates and the high content of non-soluble fiber that affected the nutrients availability for the bacterial strains. The pH changes indicated the presence of short-chain fatty acids (SCFAs), being acetate (46-100%) the main SCFA. Changes in the proteome concerned proteins that are involved in carbohydrate and other carbohydrate pathways. The characterization of the bacteria according to the growth, metabolites, and proteins expressed allows understanding the response to the change of environmental conditions and could be useful to understand L. acidophilus LA-5 and B. bifidum 450B strains' adaptation to specific applications.

  15. Lactobacillus acidophilus CP23 with weak immunomodulatory activity lacks anchoring structure for surface layer protein.

    PubMed

    Yanagihara, Sae; Kato, Shinji; Ashida, Nobuhisa; Yamamoto, Naoyuki

    2015-05-01

    To determine the reason for the low levels of Surface layer protein A (SlpA) on CP23 cells, which might play a crucial role in the immunomodulatory effect of Lactobacillus acidophilus, the DNA sequence of the slpA gene of CP23 and L-92 strains, including the upstream region, were analyzed. Unexpectedly, there was no significant difference in the predicted amino acid sequence of the C-terminus needed for cell anchoring, and only an additional Ala-Val-Ala sequence inserted in the N-terminal region of the mature CP23 protein. Therefore, anchoring of SlpA on the cell wall of CP23 and L-92 was evaluated by a reconstitution assay, which showed that SlpA released by LiCl treatment from both CP23 and L-92 was successfully anchored on LiCl-treated L-92 cells, but not on LiCl-treated CP23 cells. Moreover, quantitative analysis of SlpA protein in the culture medium of CP23 and L-92 by ELISA revealed higher levels of SlpA secretion in CP23 cells than in L-92 cells. Collectively, these results suggest that the lower levels of SlpA on the surface of CP23 cells might be caused by less cell wall capacity for SlpA anchoring, leading to an accumulation of SlpA in the culture medium of CP23 cells. The present study supports the importance of cell surface structure of L. acidophilus L-92 for SlpA anchoring on the cell surface needed for immunomodulatory effect.

  16. Dendritic Cell Targeting of Bacillus anthracis Protective Antigen Expressed by Lactobacillus acidophilus Protects Mice from Lethal Challenge

    DTIC Science & Technology

    2008-10-28

    Dendritic cell targeting of Bacillus anthracis protective antigen expressed by Lactobacillus acidophilus protects mice from lethal challenge M...lethal chal- lenge. A vaccine strategy was established by using Lactobacillus acidophilus to deliver Bacillus anthracis protective antigen (PA) via...4. TITLE AND SUBTITLE Dendritic cell targeting of Bacillus anthracis protective antigen expressed by Lactobacillus acidophilus protects mice

  17. Multivariate analysis of proteolysis patterns differentiated the impact of six strains of probiotic bacteria on a semi-hard cheese.

    PubMed

    Bergamini, C V; Hynes, E R; Candioti, M C; Zalazar, C A

    2009-06-01

    The individual contribution of 6 strains of probiotic bacteria (3 of Lactobacillus acidophilus and 3 of the Lactobacillus casei group) to proteolysis patterns in a semi-hard cheese was assessed. Control cheeses (without probiotics) and 2 types of experimental cheeses (with the addition of probiotics either directly to milk or by a 2-step fermentation method) were manufactured. Cheeses containing Lb. acidophilus showed the most extensive peptidolysis, which was evidenced by changes in the peptide profiles and a noticeable increase of free amino acids compared with control cheeses. The strains of the Lb. casei group showed a lower contribution to cheese peptidolysis, which consisted mainly of free amino acid increase. Two-step fermentation improved peptidolytic activity for only one of the cultures of Lb. acidophilus tested. The addition of Lb. acidophilus strains into cheese may be suitable not only for their beneficial health effect but also for their influence on secondary proteolysis, consistent with acceleration of ripening and improved flavor formation.

  18. Lactobacillus acidophilus Mixture in Treatment of Children Hospitalized With Acute Diarrhea.

    PubMed

    Pinto, Jamie M; Petrova, Anna

    2016-11-01

    Despite unproven effectiveness, Lactobacillus acidophilus is a widely used probiotic in the treatment of pediatric diarrhea. In this report, we evaluated the association between length of stay (LOS) for 290 young children hospitalized with acute diarrhea and adjuvant therapy with a probiotic mixture containing 80% L acidophilus that was included in treatment for 22.4% of them. Overall, no association between LOS and use of L acidophilus was recorded after controlling for age, length of diarrhea symptoms, duration of intravenous fluids, and prior exposure to antibiotic. However, LOS was directly associated with use of L acidophilus in children with negative stool studies, and no such association was recorded in children with positive stool for rotavirus or other infections. We concluded that adjuvant therapy with L acidophilus mixture is not beneficial for young children hospitalized with acute diarrhea.

  19. AcmB Is an S-Layer-Associated β-N-Acetylglucosaminidase and Functional Autolysin in Lactobacillus acidophilus NCFM

    PubMed Central

    Johnson, Brant R.

    2016-01-01

    ABSTRACT Autolysins, also known as peptidoglycan hydrolases, are enzymes that hydrolyze specific bonds within bacterial cell wall peptidoglycan during cell division and daughter cell separation. Within the genome of Lactobacillus acidophilus NCFM, there are 11 genes encoding proteins with peptidoglycan hydrolase catalytic domains, 9 of which are predicted to be functional. Notably, 5 of the 9 putative autolysins in L. acidophilus NCFM are S-layer-associated proteins (SLAPs) noncovalently colocalized along with the surface (S)-layer at the cell surface. One of these SLAPs, AcmB, a β-N-acetylglucosaminidase encoded by the gene lba0176 (acmB), was selected for functional analysis. In silico analysis revealed that acmB orthologs are found exclusively in S-layer- forming species of Lactobacillus. Chromosomal deletion of acmB resulted in aberrant cell division, autolysis, and autoaggregation. Complementation of acmB in the ΔacmB mutant restored the wild-type phenotype, confirming the role of this SLAP in cell division. The absence of AcmB within the exoproteome had a pleiotropic effect on the extracellular proteins covalently and noncovalently bound to the peptidoglycan, which likely led to the observed decrease in the binding capacity of the ΔacmB strain for mucin and extracellular matrices fibronectin, laminin, and collagen in vitro. These data suggest a functional association between the S-layer and the multiple autolysins noncovalently colocalized at the cell surface of L. acidophilus NCFM and other S-layer-producing Lactobacillus species. IMPORTANCE Lactobacillus acidophilus is one of the most widely used probiotic microbes incorporated in many dairy foods and dietary supplements. This organism produces a surface (S)-layer, which is a self-assembling crystalline array found as the outermost layer of the cell wall. The S-layer, along with colocalized associated proteins, is an important mediator of probiotic activity through intestinal adhesion and modulation of

  20. Predominant genera of fecal microbiota in children with atopic dermatitis are not altered by intake of probiotic bacteria Lactobacillus acidophilus NCFM and Bifidobacterium animalis subsp. lactis Bi-07.

    PubMed

    Larsen, Nadja; Vogensen, Finn K; Gøbel, Rikke; Michaelsen, Kim F; Abu Al-Soud, Waleed; Sørensen, Søren J; Hansen, Lars H; Jakobsen, Mogens

    2011-03-01

    The effect of probiotic bacteria Lactobacillus acidophilus NCFM and Bifidobacterium lactis Bi-07 on the composition of the Lactobacillus group, Bifidobacterium and the total bacterial population in feces from young children with atopic dermatitis was investigated. The study included 50 children randomized to intake of one of the probiotic strain or placebo. Microbial composition was characterized by denaturing gradient gel electrophoresis, quantitative PCR and, in a subset of subjects, by pyrosequencing of the 16S rRNA gene. The core population of the Lactobacillus group was identified as Lactobacillus gasseri, Lactobacillus fermentum, Lactobacillus oris, Leuconostoc mesenteroides, while the bifidobacterial community included Bifidobacterium adolescentis, Bifidobacterium bifidum, Bifidobacterium longum and Bifidobacterium catenulatum. The fecal numbers of L. acidophilus and B. lactis increased significantly after intervention, indicating survival of the ingested bacteria. The levels of Bifidobacterium correlated positively (P=0.03), while the levels of the Lactobacillus group negatively (P=0.01) with improvement of atopic eczema evaluated by the Severity Scoring of Atopic Dermatitis index. This correlation was observed across the whole study cohort and not attributed to the probiotic intake. The main conclusion of the study is that administration of L. acidophilus NCFM and B. lactis Bi-07 does not affect the composition and diversity of the main bacterial populations in feces.

  1. Characterization of Selected Lactobacillus Strains for Use as Probiotics

    PubMed Central

    Song, Minyu; Yun, Bohyun; Moon, Jae-Hak; Park, Dong-June; Lim, Kwangsei; Oh, Sejong

    2015-01-01

    The aim of this study was to evaluate the functional properties of lactic acid bacteria from various sources and to identify strains for use as probiotics. Ten Lactobacillus strains were selected and their properties such as bile tolerance, acid resistance, cholesterol assimilation activity, and adherence to HT-29 cells were assessed to determine their potential as probiotics. Lactobacillus sp. JNU 8829, L. casei MB3, L. sakei MA9, L. sakei CH8, and L. acidophilus M23 were found to show full tolerance to the 0.3% bile acid. All strains without L. acidophilus M23 were the most acid-tolerant strains. After incubating the strains at pH 2.5 for 2 h, their viability decreased by 3 Log cells. Some strains survived at pH 2.5 in the presence of pepsin and 0.3% bile acid. Lactobacillus sp. JNU 8829, L. acidophilus KU41, L. acidophilus M23, L. fermentum NS2, L. plantarum M13, and L. plantarum NS3 were found to reduce cholesterol levels by >50% in vitro. In the adhesion assay, Lactobacillus sp. JNU 8829, L. casei MB3, L. sakei MA9, and L. sakei CH8 showed higher adhesion activities after 2 h of co-incubation with the intestinal cells. The results of this comprehensive analysis shows that this new probiotic strain named, Lactobacillus sp. JNU 8829 could be a promising candidate for dairy products. PMID:26761878

  2. Antimicrobial effects of Lactobacillus plantarum and Lactobacillus acidophilus against multidrug-resistant enteroaggregative Escherichia coli.

    PubMed

    Kumar, Manesh; Dhaka, Pankaj; Vijay, Deepthi; Vergis, Jess; Mohan, Vysakh; Kumar, Ashok; Kurkure, Nitin V; Barbuddhe, Sukhadeo B; Malik, S V S; Rawool, Deepak B

    2016-09-01

    The in vitro and in vivo antimicrobial effects of Lactobacillus plantarum and Lactobacillus acidophilus were evaluated individually and synergistically against multidrug-resistant enteroaggregative Escherichia coli (MDR-EAEC). In vitro evaluation of each probiotic strain when co-cultured with MDR-EAEC isolates revealed a reduction in MDR-EAEC counts (eosin-methylene blue agar) in a dose- and time-dependent manner: probiotics at a dose rate of 10(10) CFU inhibited MDR-EAEC isolates at 72 h post-inoculation (PI), whereas at lower concentrations (10(8) and 10(9) CFU) MDR-EAEC isolates were inhibited at 96 h PI. The synergistic antimicrobial effect of both probiotic strains (each at 10(10) CFU) was highly significant (P < 0.01) and inhibited the growth of MDR-EAEC isolates at 24 h PI. For in vivo evaluation, weaned mice were fed orally with 10(7) CFU of MDR-EAEC. At Day 3 post-infection, treated mice were fed orally with the probiotic strains (each at 10(10) CFU). Compared with the control, post-treatment a significant (P < 0.01) reduction in MDR-EAEC counts was observed in faeces by Day 2 and in intestinal tissues of treated mice by Days 3 and 4 as evidenced by plate count (mean 2.71 log and 2.27 log, respectively) and real-time PCR (mean 1.62 log and 1.57 log, respectively) methods. Histopathologically, comparatively mild changes were observed in the ileum and colon from Days 3 to 5 post-treatment with probiotics; however, from Day 6 the changes were regenerative or normal. These observations suggest that these probiotic strains can serve as alternative therapeutics against MDR-EAEC-associated infections in humans and animals.

  3. Mucosal Immunogenicity of Genetically Modified Lactobacillus acidophilus Expressing an HIV-1 Epitope within the Surface Layer Protein

    PubMed Central

    Kajikawa, Akinobu; Zhang, Lin; LaVoy, Alora; Bumgardner, Sara; Klaenhammer, Todd R.; Dean, Gregg A.

    2015-01-01

    Surface layer proteins of probiotic lactobacilli are theoretically efficient epitope-displaying scaffolds for oral vaccine delivery due to their high expression levels and surface localization. In this study, we constructed genetically modified Lactobacillus acidophilus strains expressing the membrane proximal external region (MPER) from human immunodeficiency virus type 1 (HIV-1) within the context of the major S-layer protein, SlpA. Intragastric immunization of mice with the recombinants induced MPER-specific and S-layer protein-specific antibodies in serum and mucosal secretions. Moreover, analysis of systemic SlpA-specific cytokines revealed that the responses appeared to be Th1 and Th17 dominant. These findings demonstrated the potential use of the Lactobacillus S-layer protein for development of oral vaccines targeting specific peptides. PMID:26509697

  4. In vivo gut transcriptome responses to Lactobacillus rhamnosus GG and Lactobacillus acidophilus in neonatal gnotobiotic piglets

    PubMed Central

    Kumar, Anand; Vlasova, Anastasia N; Liu, Zhe; Chattha, Kuldeep S; Kandasamy, Sukumar; Esseili, Malak; Zhang, Xiaoli; Rajashekara, Gireesh; Saif, Linda J

    2014-01-01

    Probiotics facilitate mucosal repair and maintain gut homeostasis. They are often used in adjunct with rehydration or antibiotic therapy in enteric infections. Lactobacillus spp have been tested in infants for the prevention or treatment of various enteric conditions. However, to aid in rational strain selection for specific treatments, comprehensive studies are required to delineate and compare the specific molecules and pathways involved in a less complex but biologically relevant model (gnotobiotic pigs). Here we elucidated Lactobacillus rhamnosus (LGG) and L. acidophilus (LA) specific effects on gut transcriptome responses in a neonatal gnotobiotic (Gn) pig model to simulate responses in newly colonized infants. Whole genome microarray, followed by biological pathway reconstruction, was used to investigate the host-microbe interactions in duodenum and ileum at early (day 1) and later stages (day 7) of colonization. Both LA and LGG modulated common responses related to host metabolism, gut integrity, and immunity, as well as responses unique to each strain in Gn pigs. Our data indicated that probiotic establishment and beneficial effects in the host are guided by: (1) down-regulation or upregulation of immune function-related genes in the early and later stages of colonization, respectively, and (2) alternations in metabolism of small molecules (vitamins and/or minerals) and macromolecules (carbohydrates, proteins, and lipids). Pathways related to immune modulation and carbohydrate metabolism were more affected by LGG, whereas energy and lipid metabolism-related transcriptome responses were prominently modulated by LA. These findings imply that identification of probiotic strain-specific gut responses could facilitate the rational design of probiotic-based interventions to moderate specific enteric conditions. PMID:24637605

  5. Lactobacillus acidophilus NCFM affects vitamin E acetate metabolism and intestinal bile acid signature in monocolonized mice.

    PubMed

    Roager, Henrik M; Sulek, Karolina; Skov, Kasper; Frandsen, Henrik L; Smedsgaard, Jørn; Wilcks, Andrea; Skov, Thomas H; Villas-Boas, Silas G; Licht, Tine R

    2014-01-01

    Monocolonization of germ-free (GF) mice enables the study of specific bacterial species in vivo. Lactobacillus acidophilus NCFM(TM) (NCFM) is a probiotic strain; however, many of the mechanisms behind its health-promoting effect remain unknown. Here, we studied the effects of NCFM on the metabolome of jejunum, cecum, and colon of NCFM monocolonized (MC) and GF mice using liquid chromatography coupled to mass-spectrometry (LC-MS). The study adds to existing evidence that NCFM in vivo affects the bile acid signature of mice, in particular by deconjugation. Furthermore, we confirmed that carbohydrate metabolism is affected by NCFM in the mouse intestine as especially the digestion of oligosaccharides (penta- and tetrasaccharides) was increased in MC mice. Additionally, levels of α-tocopherol acetate (vitamin E acetate) were higher in the intestine of GF mice than in MC mice, suggesting that NCFM affects the vitamin E acetate metabolism. NCFM did not digest vitamin E acetate in vitro, suggesting that direct bacterial metabolism was not the cause of the altered metabolome in vivo. Taken together, our results suggest that NCFM affects intestinal carbohydrate metabolism, bile acid metabolism and vitamin E metabolism, although it remains to be investigated whether this effect is unique to NCFM.

  6. SIGNR3-dependent immune regulation by Lactobacillus acidophilus surface layer protein A in colitis.

    PubMed

    Lightfoot, Yaíma L; Selle, Kurt; Yang, Tao; Goh, Yong Jun; Sahay, Bikash; Zadeh, Mojgan; Owen, Jennifer L; Colliou, Natacha; Li, Eric; Johannssen, Timo; Lepenies, Bernd; Klaenhammer, Todd R; Mohamadzadeh, Mansour

    2015-04-01

    Intestinal immune regulatory signals govern gut homeostasis. Breakdown of such regulatory mechanisms may result in inflammatory bowel disease (IBD). Lactobacillus acidophilus contains unique surface layer proteins (Slps), including SlpA, SlpB, SlpX, and lipoteichoic acid (LTA), which interact with pattern recognition receptors to mobilize immune responses. Here, to elucidate the role of SlpA in protective immune regulation, the NCK2187 strain, which solely expresses SlpA, was generated. NCK2187 and its purified SlpA bind to the C-type lectin SIGNR3 to exert regulatory signals that result in mitigation of colitis, maintenance of healthy gastrointestinal microbiota, and protected gut mucosal barrier function. However, such protection was not observed in Signr3(-/-) mice, suggesting that the SlpA/SIGNR3 interaction plays a key regulatory role in colitis. Our work presents critical insights into SlpA/SIGNR3-induced responses that are integral to the potential development of novel biological therapies for autoinflammatory diseases, including IBD.

  7. Inhibition of Cronobacter sakazakii by Lactobacillus acidophilus n.v. Er2 317/402

    PubMed Central

    Lee, Jong Suk; Lee, Junsoo

    2016-01-01

    Lactobacillus acidophilus n.v. Er2 317/402 strain Narine is known as a health beneficial functional probiotic culture and supplementary source of nutrition for newborns. In this study, in vitro antimicrobial activities of Narine-lyophilized (Narine-L), Narine-heat treated (Narine-HT), and Narine crude cell-free extract (Narine-CCFE) were evaluated against pathogen Cronobacter sakazakii (C. sakazakii) in agar as well as in a reconstituted powdered infant formula (RPIF) model. Inhibition zones of 30 mg Narine-L and Narine-HT were both 150 U, whereas inhibition zone of 30 mg Narine-CCFE was 200 U. Narine-L (1 g) and Narine-HT (1 g) were added to 10 mL of artificially contaminated RPIF, respectively, containing 100 μL of C. sakazakii (1.62×108 colony forming unit (CFU)/mL). After treatment with Narine-L and Narine-HT for 3 h and 6 h at 37℃, less than ≤107 CFU/mL of C. sakazakii was detected in RPIF. Without Narine-L and Narine-HT treatment, the population of C. sakazakii increased up to 5.36×109 CFU/mL after 6 h. Examination by transmission electron microscopy confirmed C. sakazakii cells were damaged by Narine-CCFE. Thus, employing Narine culture as a natural and safe bio-preservative may protect infants from C. sakazakii. PMID:27857539

  8. Lactobacillus acidophilus contributes to a healthy environment for vaginal epithelial cells.

    PubMed

    Pi, Woojin; Ryu, Jae-Sook; Roh, Jaesook

    2011-09-01

    Lactobacillus species in the female genital tract are thought to act as a barrier to infection. Several studies have demonstrated that lactobacilli can adhere to vaginal epithelial cells. However, little is known about how the adherence of lactobacilli to vaginal epithelial cells affects the acidity, cell viability, or proliferation of the lactobacilli themselves or those of vaginal epithelial cells. Lactobacillus acidophilus was co-cultured with immortalized human vaginal epithelial cells (MS74 cell line), and the growth of L. acidophilus and the acidity of the culture medium were measured. MS74 cell density and viability were also assessed by counting cell numbers and observing the cell attachment state. L. acidophilus showed exponential growth for the first 6 hr until 9 hr, and the pH was maintained close to 4.0-5.0 at 24 hr after culture, consistent with previous studies. The growth curve of L. acidophilus or the pH values were relatively unaffected by co-culture with MS74 cells, confirming that L. acidophilus maintains a low pH in the presence of MS74 cells. This co-culture model could therefore potentially be used to mimic vaginal conditions for future in vitro studies. On the other hand, MS74 cells co-cultured with L. acidophilus more firmly attached to the culture plate, and a higher number of cells were present compared to cells cultured in the absence of L. acidophilus. These results indicate that L. acidophilus increases MS74 cell proliferation and viability, suggesting that lactobacilli may contribute to the healthy environment for vaginal epithelial cells.

  9. Phenol degradation by Sulfobacillus acidophilus TPY via the meta-pathway.

    PubMed

    Zhou, Wengen; Guo, Wenbin; Zhou, Hongbo; Chen, Xinhua

    2016-09-01

    Due to its toxicity and volatility, phenol must be cleared from the environment. Sulfobacillus acidophilus TPY, which was isolated from a hydrothermal vent in the Pacific Ocean as a moderately thermoacidophilic Gram-positive bacterium, was capable of aerobically degrading phenol. This bacterium could tolerate up to 1300mg/L phenol and degrade 100mg/L phenol in 40h completely at 45°C and pH 1.8 with a maximal degradation rate of 2.32mg/L/h at 38h. Genome-wide search revealed that one gene (TPY_3176) and 14 genes clustered together in two regions with locus tags of TPY_0628-0634 and TPY_0640-0646 was proposed to be involved in phenol degradation via the meta-pathway with both the 4-oxalocrotonate branch and the hydrolytic branch. Real-time PCR analysis of S. acidophilus TPY under phenol cultivation condition confirmed the transcription of proposed genes involved in the phenol degradation meta-pathway. Degradation of 3-methylphenol and 2-methylphenol confirmed that the hydrolytic branch was utilised by S. acidophilus TPY. Phylogenetic analysis revealed that S. acidophilus TPY was closely related to sulphate-reducing bacteria and some Gram-positive phenol-degrading bacteria. This was the first report demonstrating the ability of S. acidophilus to degrade phenol and characterising the putative genes involved in phenol metabolism in S. acidophilus TPY.

  10. Identification of Lactobacillus UFV H2B20 (probiotic strain) using DNA-DNA hybridization

    PubMed Central

    de Magalhães, J.T.; Uetanabaro, A.P. T.; de Moraes, C.A.

    2008-01-01

    Sequence analyses of the 16S rDNA gene and DNA-DNA hybridization tests were performed for identification of the species of the probiotic Lactobacillus UFV H2b20 strain. Using these two tests, we concluded that this strain, originally considered Lact. acidophilus, should be classified as Lact. delbrueckii. PMID:24031263

  11. Effect of Lactobacillus acidophilus NS1 on plasma cholesterol levels in diet-induced obese mice.

    PubMed

    Song, M; Park, S; Lee, H; Min, B; Jung, S; Park, S; Kim, E; Oh, S

    2015-03-01

    We investigated the probiotic properties of Lactobacillus acidophilus NS1, such as acid resistance, bile tolerance, adherence to HT-29 cells, and cholesterol assimilation activity. In an animal study, 7-wk-old male C57BL/6 mice were fed a normal diet, a high-fat diet (HFD), or an HFD with L. acidophilus NS1 (ca. 1.0×10(8) cfu/mL) for 10 wk. Total cholesterol and low-density lipoprotein (LDL) cholesterol levels were significantly lower in mice fed an HFD with L. acidophilus NS1 than in those fed an HFD only, whereas high-density lipoprotein cholesterol levels were similar between these 2 groups. To understand the mechanism of the cholesterol-lowering effect of L. acidophilus NS1 on the HFD-mediated increase in plasma cholesterol levels, we determined mRNA levels of genes involved in cholesterol homeostasis in the liver. Expression of sterol regulatory element-binding protein 2 (Srebp2) and LDL receptor (Ldlr) in the liver was dramatically reduced in mice fed a HFD compared with those fed a normal diet. When L. acidophilus NS1 was administered orally to HFD-fed mice, an HFD-induced suppression of Srebp2 and Ldlr expression in the liver was abolished. These results suggest that the oral administration of L. acidophilus NS1 to mice fed an HFD increased the expression of Srebp2 and Ldlr in the liver, which was inhibited by high fat intake, thus leading to a decrease in plasma cholesterol levels. Lactobacillus acidophilus NS1 could be a useful probiotic microorganism for cholesterol-lowering dairy products and the improvement of hyperlipidemia and hepatic lipid metabolism.

  12. A novel NADPH-dependent reductase of Sulfobacillus acidophilus TPY phenol hydroxylase: expression, characterization, and functional analysis.

    PubMed

    Li, Meng; Guo, Wenbin; Chen, Xinhua

    2016-12-01

    The reductase component (MhpP) of the Sulfobacillus acidophilus TPY multicomponent phenol hydroxylase exhibits only 40 % similarity to Pseudomonas sp. strain CF600 phenol hydroxylase reductase. Amino acid sequence alignment analysis revealed that four cysteine residues (Cys-X 4 -Cys-X 2 -Cys-X 29-35 -Cys) are conserved in the N terminus of MhpP for [2Fe-2S] cluster binding, and two other motifs (RXYS and GXXS/T) are conserved in the C terminus for binding the isoalloxazine and phosphate groups of flavin adenine dinucleotide (FAD). Two motifs (S/T-R and yXCGp) responsible for binding to reduce nicotinamide adenine dinucleotide phosphate (NADPH) are also conserved in MhpP, although some residues differ. To confirm the function of this reductase, MhpP was heterologously expressed in Escherichia coli BL21(DE3) and purified. UV-visible spectroscopy and electron paramagnetic resonance spectroscopy revealed that MhpP contains a [2Fe-2S] cluster. MhpP mutants in which the four cysteine residues were substituted via site-directed mutagenesis lost the ability to bind the [2Fe-2S] cluster, resulting in a decrease in enzyme-specific oxidation of NADPH. Thin-layer chromatography revealed that MhpP contains FAD. Substrate specificity analyses confirmed that MhpP uses NADPH rather than NADH as an electron donor. MhpP oxidizes NADPH using cytochrome c, potassium ferricyanide, or nitro blue tetrazolium as an electron acceptor, with a specific activity of 1.7 ± 0.36, 0.78 ± 0.13, and 0.16 ± 0.06 U/mg, respectively. Thus, S. acidophilus TPY MhpP is a novel NADPH-dependent reductase component of phenol hydroxylase that utilizes FAD and a [2Fe-2S] cluster as cofactors.

  13. Probiotic cheese containing Lactobacillus rhamnosus HN001 and Lactobacillus acidophilus NCFM® modifies subpopulations of fecal lactobacilli and Clostridium difficile in the elderly.

    PubMed

    Lahtinen, Sampo J; Forssten, Sofia; Aakko, Juhani; Granlund, Linda; Rautonen, Nina; Salminen, Seppo; Viitanen, Matti; Ouwehand, Arthur C

    2012-02-01

    Aging is associated with alterations in the intestinal microbiota and with immunosenescence. Probiotics have the potential to modify a selected part of the intestinal microbiota as well as improve immune functions and may, therefore, be particularly beneficial to elderly consumers. In this randomized, controlled cross-over clinical trial, we assessed the effects of a probiotic cheese containing Lactobacillus rhamnosus HN001 and Lactobacillus acidophilus NCFM on the intestinal microbiota and fecal immune markers of 31 elderly volunteers and compared these effects with the administration of the same cheese without probiotics. The probiotic cheese was found to increase the number of L. rhamnosus and L. acidophilus NCFM in the feces, suggesting the survival of the strains during the gastrointestinal transit. Importantly, probiotic cheese administration was associated with a trend towards lower counts of Clostridium difficile in the elderly, as compared with the run-in period with the plain cheese. The effect was statistically significant in the subpopulation of the elderly who harbored C. difficile at the start of the study. The probiotic cheese was not found to significantly alter the levels of the major microbial groups, suggesting that the microbial changes conferred by the probiotic cheese were limited to specific bacterial groups. Despite that the administration of the probiotic cheese to the study population has earlier been shown to significantly improve the innate immunity of the elders, we did not observe measurable changes in the fecal immune IgA concentrations. No increase in fecal calprotectin and β-defensin concentrations suggests that the probiotic treatment did not affect intestinal inflammatory markers. In conclusion, the administration of probiotic cheese containing L. rhamnosus HN001 and L. acidophilus NCFM, was associated with specific changes in the intestinal microbiota, mainly affecting specific subpopulations of intestinal lactobacilli and C

  14. Capsicum annuum enhances L-lactate production by Lactobacillus acidophilus: implication in curd formation.

    PubMed

    Sharma, Smriti; Jain, Sriyans; Nair, Girija N; Ramachandran, Srinivasan

    2013-07-01

    Lactobacillus acidophilus is commonly used lactic acid bacteria for producing fermented milk products. In general household practice, curdling is known to occur faster in the presence of red chili. Herein we analyzed the enhanced effect of red chili (Capsicum annuum) and its major component, capsaicin, on Lactobacillus acidophilus (ATCC 4356) in the production of L-lactate in de Man, Rogosa, and Sharpe medium at various temperatures (15, 20, 25, 30, and 37°C). The addition of red chili showed significant increase in the amount of L-lactate produced by L. acidophilus compared with the control at all temperatures. Similar results were observed with addition of capsaicin alone. This was accompanied by an increase in the consumption of d-glucose. Capsazepine, a known antagonist of capsaicin, inhibited the production of L-lactate by L. acidophilus in the presence of both capsaicin and red chili. Because no increase occurred in the growth of L. acidophilus in the presence of red chili, the enhanced production of L-lactate in the presence of red chili or capsaicin is due to increased metabolic activity.

  15. Probiotic Crescenza cheese containing Lactobacillus casei and Lactobacillus acidophilus manufactured with high-pressure homogenized milk.

    PubMed

    Burns, P; Patrignani, F; Serrazanetti, D; Vinderola, G C; Reinheimer, J A; Lanciotti, R; Guerzoni, M E

    2008-02-01

    High-pressure homogenization (HPH) is one of the most promising alternatives to traditional thermal treatment of food preservation and diversification. Its effectiveness on the deactivation of pathogenic and spoilage microorganisms in model systems and real food is well documented. To evaluate the potential of milk treated by HPH for the production of Crescenza cheese with commercial probiotic lactobacilli added, 4 types of cheeses were made: HPH (from HPH-treated milk), P (from pasteurized milk), HPH-P (HPH-treated milk plus probiotics), and P-P (pasteurized milk plus probiotics) cheeses. A strain of Streptococcus thermophilus was used as starter culture for cheese production. Compositional, microbiological, physicochemical, and organoleptic analyses were carried out at 1, 5, 8, and 12 d of refrigerated storage (4 degrees C). According to results obtained, no significant differences among the 4 cheese types were observed for gross composition (protein, fat, moisture) and pH. Differently, the HPH treatment of milk increased the cheese yield about 1% and positively affected the viability during the refrigerated storage of the probiotic bacteria. In fact, after 12 d of storage, the Lactobacillus paracasei A13 cell loads were 8 log cfu/ g, whereas Lactobacillus acidophilus H5 exhibited, in P-P cheese, a cell load decrease of about 1 log cfu/g with respect to the HPH-P cheese. The hyperbaric treatment had a significant positive effect on free fatty acids release and cheese proteolysis. Also, probiotic cultures affected proteolytic and lipolytic cheese patterns. No significant differences were found for the sensory descriptors salty and creamy among HPH and P cheeses as well as for acid, piquant, sweet, milky, salty, creamy, and overall acceptance among HPH, HPH-P, and P-P Crescenza cheeses.

  16. Detection of Lactobacillus acidophilus in Feces of Humans, Pigs, and Chickens1

    PubMed Central

    Gilliland, S. E.; Speck, M. L.; Morgan, C. G.

    1975-01-01

    Lactobacilli in fecal material from humans, pigs, and chickens were enumerated on lactobacillus selective agar (LBS). In all samples, higher numbers of lactobacilli were detected when plates were incubated in a system flushed with CO2 rather than in air. Much higher numbers of bacteria from human feces were detected when the LBS agar plates were incubated anaerobically in a hydrogen-carbon dioxide atmosphere (GasPak) than when incubated in CO2. The bacteria from human feces isolated on LBS agar incubated anaerobically were predominately bifidobacteria. Cultures from all three sources isolated on LBS agar incubated under CO2 were lactobacilli, including Lactobacillus acidophilus. Differences were observed in biochemical characteristics of some of the L. acidophilus isolated from all three sources. Guanine plus cytosine base ratios of deoxyribonucleic acid isolated from L. acidophilus cultures from humans were lower, in most cases, than those from pigs and chickens. PMID:811162

  17. Transmission of Lactobacillus jensenii and Lactobacillus acidophilus from mother to child at time of delivery.

    PubMed Central

    Carlsson, J; Gothefors, L

    1975-01-01

    The presence of Lactobacillus jensenii and Lactobacillus acidophilus has been studied in specimens from the rectum and vagina of the mother, from the mouth of the infant at the time of delivery, and from the mouth and rectum of infants six days of age. L. jensenii could be differentiated from other species of lactobacilli by the following combination of characteristics: production of only D-lactate, hydrolysis of arginine, and fermentation of cellobiose, galactose, and ribose, but not of lactose. L. jensenii and L. acidophilus were common inhabitants of the vagina. In spite of a contamination of the infant's mouth by L. jensenii and L. acidophilus during delivery, neither of these organisms became established in the mouth of the newborn infants. PMID:809467

  18. Improved bioavailability of dietary phenolic acids in whole grain barley and oat groat following fermentation with probiotic Lactobacillus acidophilus , Lactobacillus johnsonii , and Lactobacillus reuteri.

    PubMed

    Hole, Anastasia S; Rud, Ida; Grimmer, Stine; Sigl, Stefanie; Narvhus, Judith; Sahlstrøm, Stefan

    2012-06-27

    The aim of this study was to improve the bioavailability of the dietary phenolic acids in flours from whole grain barley and oat groat following fermentation with lactic acid bacteria (LAB) exhibiting high feruloyl esterase activity (FAE). The highest increase of free phenolic acids was observed after fermentation with three probiotic strains, Lactobacillus johnsonii LA1, Lactobacillus reuteri SD2112, and Lactobacillus acidophilus LA-5, with maximum increases from 2.55 to 69.91 μg g(-1) DM and from 4.13 to 109.42 μg g(-1) DM in whole grain barley and oat groat, respectively. Interestingly, higher amounts of bound phenolic acids were detected after both water treatment and LAB fermentation in whole grain barley, indicating higher bioaccessibility, whereas some decrease was detected in oat groat. To conclude, cereal fermentation with specific probiotic strains can lead to significant increase of free phenolic acids, thereby improving their bioavailability.

  19. Lactobacillus acidophilus ATCC 4356 attenuates the atherosclerotic progression through modulation of oxidative stress and inflammatory process.

    PubMed

    Chen, Lihua; Liu, Wenen; Li, Yanming; Luo, San; Liu, Qingxia; Zhong, Yiming; Jian, Zijuan; Bao, Meihua

    2013-09-01

    The aim of this study was to investigate the effect of Lactobacillus (L.) acidophilus ATCC 4356 on the progression of atherosclerosis in Apoliprotein-E knockout (ApoE(-/-)) mice and the underlying mechanisms. Eight week-old ApoE(-/-) mice were treated with L. acidophilus ATCC 4356 daily for 12 weeks. The wild type (WT) mice or ApoE(-/-) mice in the vehicle group were treated with saline only. Body weights, serum lipid levels, aortic atherosclerotic lesions, and tissue oxidative and inflammatory statuses were examined among the groups. As compared to ApoE(-/-) mice in the vehicle group, ApoE(-/-) mice treated with L. acidophilus ATCC 4356 had no changes in body weights and serum lipid profiles, but showed decreased atherosclerotic lesion size in en face aorta. In comparison with WT mice, ApoE(-/-) mice in the vehicle group showed higher levels of serum malondialdehyde (MDA), oxidized low density lipoprotein (oxLDL) and tumor necrosis factor-alpha (TNF-α), but lower levels of interleukin-10 (IL-10) and superoxide dismutase (SOD) activities in serum. Administration of L. acidophilus ATCC 4356 could reverse these trends in a dose-dependent manner in ApoE(-/-) mice. Furthermore, ApoE(-/-) mice treated with L. acidophilus ATCC 4356 showed an inhibition of translocation of NF-κB p65 from cytoplasm to nucleus, suppression of degradation of aortic IκB-α, and improvements of gut microbiota distribution, as compared to ApoE(-/-) mice in the vehicle group. Our findings suggest that administration of L. acidophilus ATCC 4356 can attenuate the development of atherosclerotic lesions in ApoE(-/-) mice through reducing oxidative stress and inflammatory response.

  20. Effect of Lactobacillus acidophilus and zinc bacitracin as dietary additives for broiler chickens.

    PubMed

    Abdulrahim, S M; Haddadin, M S; Odetallah, N H; Robinson, R K

    1999-03-01

    The influence of Lactobacillus acidophilus and zinc bacitracin alone, or in combination, on the growth of broiler chickens was monitored over a period of 8 weeks. 2. The maximum improvement in body weight over the controls was 10.8% with both additives in the diet but the use of bacitracin alone induced a 9.1% improvement. 3. Food conversion was reduced by zinc bacitracin alone but was improved by the use of L. acidophilus and bacitracin in combination. 4. The combination treatment increased abdominal fat deposition in the female chickens by 31%.

  1. S-layer protein of Lactobacillus acidophilus ATCC 4356: purification, expression in Escherichia coli, and nucleotide sequence of the corresponding gene.

    PubMed Central

    Boot, H J; Kolen, C P; van Noort, J M; Pouwels, P H

    1993-01-01

    The cell surfaces of several Lactobacillus species are covered by a regular layer composed of a single species of protein, the S-protein. The 43-kDa S-protein of the neotype strain Lactobacillus acidophilus ATCC 4356, which originated from the pharynx of a human, was purified. Antibodies generated against purified S-protein were used to screen a lambda library containing chromosomal L. acidophilus ATCC 4356 DNA. Several phages showing expression of this S-protein in Escherichia coli were isolated. A 4.0-kb DNA fragment of one of those phages hybridized to a probe derived from an internal tryptic fragment of the S-protein. The slpA gene, coding for the surface layer protein, was located entirely on the 4.0-kb fragment as shown by deletion analysis. The nucleotide sequence of the slpA gene was determined and appeared to encode a protein of 444 amino acids. The first 24 amino acids resembled a putative secretion signal, giving rise to a mature S-protein of 420 amino acids (44.2 kDa). The predicted isoelectric point of 9.4 is remarkably high for an S-protein but is in agreement with the data obtained during purification. The expression of the entire S-protein or of large, C-terminally truncated S-proteins is unstable in E. coli. Images PMID:8407780

  2. Use of Lactobacillus acidophilus and Lactobacillus casei for a potential probiotic legume-based fermented product using pigeon pea (Cajanus cajan).

    PubMed

    Parra, K; Ferrer, M; Piñero, M; Barboza, Y; Medina, L M

    2013-02-01

    The aim of the present study was to evaluate the use of pigeon pea (Cajanus cajan) as an appropriate substrate in the production of a legume-based fermented product with Lactobacillus acidophilus ATCC 314 or Lactobacillus casei ATCC 393 and then to ascertain the effects of the addition of ingredients such as powdered milk and banana or strawberry sauce. The products were analyzed for viable cell counts, pH, and sensory attributes during product manufacture and throughout the refrigerated storage period at 3, 7, 14, 21, and 28 days. Nine types of products were produced. At the end of the storage period, the viability of L. acidophilus was above 7 log CFU/g in the presence of milk and 20% sucrose fruit sauce. For products with L. casei, the lack of ingredients such as milk caused no significant loss in viability; however, a high concentration of sucrose in the fruit sauce was an important factor in maintaining a high L. casei population. L. casei had high viability and good sensory attributes. Both strains could be considered suitable for a pigeon pea-based fermented potential probiotic product and a low-cost protein source.

  3. Potential for tyndalized Lactobacillus acidophilus as an effective component in moisturizing skin and anti-wrinkle products.

    PubMed

    Im, A-Rang; Kim, Hui Seong; Hyun, Jin Won; Chae, Sungwook

    2016-08-01

    It is widely accepted that ultraviolet (UV) irradiation induces skin damage. In the present study, a UVB-induced hairless mouse model of skin photoaging was developed to determine whether tyndalized Lactobacillus acidophilus was able to significantly enhance the repair of photodamaged skin. To evaluate the effects of tyndalized L. acidophilus on UVB-induced skin-wrinkle formation in vivo, HR-1 hairless male mice were exposed to UVB radiation and orally administered tyndalized L. acidophilus. Compared with the control group, the UVB irradiation mice displayed a significant increase in transepidermal water loss and a reduction in skin hydration. In mice with UVB-induced photodamage, the effacement of the fine wrinkles by tyndalized L. acidophilus was correlated with dermal collagen synthesis, accompanied by histological changes. Furthermore, western blotting was performed to investigate the protein expression levels of matrix metalloproteinases (MMPs) and mitogen-activated protein kinase. Notably, orally administered tyndalized L. acidophilus reduced the expression levels of MMP-1 and MMP-9. Based upon the aforementioned results, it was determined that tyndalized L. acidophilus effectively inhibited the wrinkle formation induced by UVB irradiation, and that this may be attributed to the downregulation of MMPs. Therefore, tyndalized L. acidophilus may be considered a potential agent for preventing skin photoaging and wrinkle formation.

  4. Lactobacillus acidophilus ATCC 4356 prevents atherosclerosis via inhibition of intestinal cholesterol absorption in apolipoprotein E-knockout mice.

    PubMed

    Huang, Ying; Wang, Jinfeng; Quan, Guihua; Wang, Xiaojun; Yang, Longfei; Zhong, Lili

    2014-12-01

    The objective of this study was to investigate the effect of Lactobacillus acidophilus ATCC 4356 on the development of atherosclerosis in apolipoprotein E-knockout (ApoE(-/-)) mice. Eight-week-old ApoE(-/-) mice were fed a Western diet with or without L. acidophilus ATCC 4356 daily for 16 weeks. L. acidophilus ATCC 4356 protected ApoE(-/-) mice from atherosclerosis by reducing their plasma cholesterol levels from 923 ± 44 to 581 ± 18 mg/dl, likely via a marked decrease in cholesterol absorption caused by modulation of Niemann-Pick C1-like 1 (NPC1L1). In addition, suppression of cholesterol absorption induced reverse cholesterol transport (RCT) in macrophages through the peroxisome proliferator-activated receptor/liver X receptor (PPAR/LXR) pathway. Fecal lactobacillus and bifidobacterium counts were significantly (P < 0.05) higher in the L. acidophilus ATCC 4356 treatment groups than in the control groups. Furthermore, L. acidophilus ATCC 4356 was detected in the rat small intestine, colon, and feces during the feeding trial. The bacterial levels remained high even after the administration of lactic acid bacteria had been stopped for 2 weeks. These results suggest that administration of L. acidophilus ATCC 4356 can protect against atherosclerosis through the inhibition of intestinal cholesterol absorption. Therefore, L. acidophilus ATCC 4356 may be a potential therapeutic material for preventing the progression of atherosclerosis.

  5. Lactobacillus acidophilus and L. reuteri modulate cytokine responses in gnotobiotic pigs infected with human rotavirus

    PubMed Central

    Azevedo, M. S. P.; Zhang, W.; Wen, K.; Gonzalez, A. M.; Saif, L. J.; Yousef, A. E.; Yuan, L.

    2012-01-01

    Probiotic lactic acid bacteria (LAB) have been shown to alleviate inflammation, enhance the immunogenicity of rotavirus vaccines, or reduce the severity of rotavirus diarrhoea. Although the mechanisms are not clear, the differential Th1/Th2/Th3-driving capacities and modulating effects on cytokine production of different LAB strains may be the key. Our goal was to delineate the influence of combining two probiotic strains L. acidophilus and L. reuteri on the development of cytokine responses in neonatal gnotobiotic pigs infected with human rotavirus (HRV). We demonstrated that HRV alone, or HRV plus LAB, but not LAB alone, initiated serum cytokine responses, as indicated by significantly higher concentrations of IFN-α, IFN-γ, IL-12, and IL-10 at post-inoculation day (PID) 2 in the HRV only and LAB+HRV+ pigs compared to LAB only and LAB-HRV- pigs. Peak cytokine responses coincided with the peak of HRV replication. LAB further enhanced the Th1 and Th2 cytokine responses to HRV infection as indicated by significantly higher concentrations of IL-12, IFN-γ, IL-4 and IL-10 in the LAB+HRV+ pigs compared to the LAB-HRV+ pigs. The LAB+HRV+ pigs maintained relatively constant concentrations of TGF-β compared to the HRV only group which had a significant increase at PID 2 and decrease at PID 7, suggesting a regulatory role of LAB in maintaining gut homeostasis. At PID 28, cytokine secreting cell (CSC) responses, measured by ELISpot, showed increased Th1 (IL-12, IFN-γ) CSC numbers in the LAB+HRV+ and LAB-HRV+ groups compared to LAB only and LAB-HRV- pigs, with significantly increased IL-12 CSCs in spleen and PBMCs and IFN-γ CSCs in spleen of the LAB+HRV+ group. Thus, HRV infection alone, but not LAB alone was effective in inducing cytokine responses but LAB significantly enhanced both Th1 and Th2 cytokines in HRV-infected pigs. LAB may also help to maintain immunological homeostasis during HRV infection by regulating TGF-β production. PMID:22348907

  6. Modulation of the Lactobacillus acidophilus La-5 lipidome by different growth conditions.

    PubMed

    Hansen, Marie-Louise R W; Clausen, Anders; Ejsing, Christer S; Risbo, Jens

    2015-10-01

    Probiotics are bacteria used in the food industry due to their potential health benefits. In this study, the plasma membrane of the probiotic Lactobacillus acidophilus La-5 was investigated using state-of-the-art high-resolution shotgun lipidomics. Comparisons of the lipidome of the plasma membrane were done after altering the fatty acid composition by supplementing L. acidophilus La-5 with saturated, mono-, di- and tri-unsaturated fatty acids during fermentation. The plasma membrane with the highest degree of saturation resulted in a lipid composition with the highest proportion of cardiolipin (CL) and lowest proportion of monolysocardiolipin (MLCL). No significant changes were found for other lipid classes. The bacteria grown with di- and tri-unsaturated fatty acids were expected to have more unsaturated plasma membranes than bacteria grown with mono-unsaturated fatty acids. This was also the case for MLCL, but the numbers of double bonds for CL were quite similar for these three samples. The results indicate that L. acidophilus La-5 possesses a molecular mechanism for remodelling and optimizing the fatty acid composition of CL and MLCL species and the molar ratio of CL and MLCL. This study contributes new knowledge on the previously uninvestigated lipidome of L. acidophilus La-5.

  7. Combined effect of Lactobacillus acidophilus and β-cyclodextrin on serum cholesterol in pigs.

    PubMed

    Alonso, L; Fontecha, J; Cuesta, P

    2016-01-14

    A total of twenty-four Yorkshire gilt pigs of 6-7 weeks of age were used in a 2×2 factorial experiment to determine the individual and combined effects of the inclusion of two dietary factors (cholesterol rich, 3% β-cyclodextrin (BCD) and Lactobacillus acidophilus cultures) on total cholesterol and LDL-cholesterol levels in blood serum. Pigs were assigned randomly to treatment groups (n 6). Total serum cholesterol concentrations decreased after 3 weeks in all the experimental treatment groups, including diets with BCD, L. acidophilus or both. Similar trends were observed for serum LDL-cholesterol concentrations among the experimental treatments. No statistically significant differences from the control group were observed in either total serum cholesterol or LDL-cholesterol concentrations (P<0·05) for each of the individual treatment groups: BCD or L. acidophilus. However, significant differences in total serum cholesterol concentrations were observed when comparing the combined treatment group (BCD and L. acidophilus) with the control group, which consisted of a basal diet and sterile milk. The combined treatment group exhibited 17·9% lower total serum cholesterol concentration after 3 weeks. Similar significant differences were observed when comparing the combined effect experimental group with the control group after 3 weeks. The combined treatment group exhibited 27·9% lower serum LDL-cholesterol concentrations.

  8. Fat-free plain yogurt manufactured with inulins of various chain lengths and Lactobacillus acidophilus.

    PubMed

    Aryana, K J; Plauche, S; Rao, R M; McGrew, P; Shah, N P

    2007-04-01

    Inulin is a prebiotic food ingredient that increases the activity of Lactobacillus acidophilus, increases calcium absorption, and is a good source of dietary fiber. The objective was to determine the effect of short, medium, and long chain inulins on the physicochemical, sensory, and microbiological characteristics of fat-free plain yogurt containing L. acidophilus. Inulins of short (P95), medium (GR), and long (HP) chain lengths were incorporated at 1.5% w/w of the yogurt mix. Viscosity, pH, syneresis, sensory properties (flavor, body and texture, and appearance and color), L. acidophilus counts, and color (L*, a*, and b*) of yogurts were determined at 1, 11, and 22 d after yogurt manufacture. The P95 containing yogurt had a significantly lower pH than the remaining yogurts, higher flavor scores than the yogurt containing HP, and comparable flavor scores with the control. The yogurts containing HP had less syneresis than the control and a better body and texture than the remaining yogurts. Yogurts containing prebiotics of different chain lengths had comparable L. acidophilus counts with each other but higher counts than the control. However, inulins of various chain lengths did not affect viscosity, color, and product appearance. Chain length of prebiotics affected some quality attributes of probiotic yogurts.

  9. Impact of oral Lactobacillus acidophilus gavage on rooster seminal and cloacal Lactobacilli concentrations.

    PubMed

    Kiess, A S; Hirai, J H; Triplett, M D; Parker, H M; McDaniel, C D

    2016-08-01

    The use of antibiotics in poultry is being heavily scrutinized, therefore alternatives such as probiotics are being investigated. Lactobacilli spp. are a commonly used bacteria in formulating probiotics, and the addition of Lactobacilli to broiler diets has demonstrated increased growth rates, stimulated immune systems, and reduced pathogen loads in the gastro-intestinal tract ( GI: ) tract. However, previous research has shown that when rooster semen is directly exposed to Lactobacillus acidophilus (L. acidophilus) sperm quality is reduced. Therefore, the objective of the current study was to determine if oral administration of L. acidophilus increases the concentration of Lactobacilli in semen as well as the cloaca. A total of 30 roosters were used: 15 roosters were gavaged with 1X PBS (Control) and 15 roosters were gavaged with 10(7) cfu/mL of L. acidophilus (Treated). All roosters were gavaged for 14 consecutive days. Semen was collected on a 3 d interval, and cloacal swabs were collected on a 2 d interval, beginning on the first day prior to oral administration. Semen and cloacal swabs were serial diluted, and 100 μL of each dilution was then plated on Man, Rogosa, Sharpe ( MRS: ) agar plates. All plates were incubated for 48 h at 37°C under anaerobic conditions and counted. All Lactobacilli counts were first log transformed, then log transformed (day 0) pre-counts were subtracted from the log transformed day counts providing log differences for the analysis. Seminal Lactobacilli counts were not altered by treatments. However, the main effect of treatment (P = 0.026) for cloacal counts indicated that roosters gavaged with Lactobacilli yielded higher counts than the controls. Additionally, cloaca samples also demonstrated a treatment by day interaction trend (P = 0.082), where Lactobacilli was higher in the L. acidophilus gavaged roosters than the controls only on days 3, 5, 13, and 15. In conclusion, the addition of L. acidophilus to the male breeder diet

  10. Construction and validation of a mCherry protein vector for promoter analysis in Lactobacillus acidophilus.

    PubMed

    Mohedano, M Luz; García-Cayuela, Tomás; Pérez-Ramos, Adrián; Gaiser, Rogier A; Requena, Teresa; López, Paloma

    2015-02-01

    Lactobacilli are widespread in natural environments and are increasingly being investigated as potential health modulators. In this study, we have adapted the broad-host-range vector pNZ8048 to express the mCherry protein (pRCR) to expand the usage of the mCherry protein for analysis of gene expression in Lactobacillus. This vector is also able to replicate in Streptococcus pneumoniae and Escherichia coli. The usage of pRCR as a promoter probe was validated in Lactobacillus acidophilus by characterizing the regulation of lactacin B expression. The results show that the regulation is exerted at the transcriptional level, with lbaB gene expression being specifically induced by co-culture of the L. acidophilus bacteriocin producer and the S. thermophilus STY-31 inducer bacterium.

  11. Modification of sweet acidophilus milk to improve utilization by lactose-intolerant persons.

    PubMed

    McDonough, F E; Hitchins, A D; Wong, N P; Wells, P; Bodwell, C E

    1987-03-01

    Enhanced digestion of yogurt by lactose-intolerant individuals is believed to be due to inherent beta-galactosidase (lactase) in the culture organisms that aids in the hydrolysis of ingested lactose. However, sweet acidophilus milk, which contains lactase-rich organisms, does not enhance lactose digestion. Using breath-hydrogen measurements to indicate malabsorption in 14 human subjects, we compared utilization of: milk, yogurt, heated yogurt, yogurt plus lactose, heated yogurt plus lactase, sweet acidophilus milk (SAM), and SAM made with sonicated cells. Results indicate that both the reduction of lactose during fermentation and the presence of indigenous bacterial lactase are responsible for the increased ability to tolerate lactose in yogurt. Improved utilization of SAM by sonication suggests that intracellular lactase is not available during digestion and that sonication releases the lactase activity from the cells.

  12. Effect of Lactobacillus acidophilus & epidermal growth factor on experimentally induced Clostridium difficile infection

    PubMed Central

    Kaur, Sukhminderjit; Vaishnavi, Chetana; Prasad, Kaushal Kishor; Ray, Pallab; Kochhar, Rakesh

    2011-01-01

    Background & objectives: Clostridium difficile-associated disease (CDAD) remains an important nosocomial ailment. Antimicrobial therapy used for CDAD gives inconsistent results. This experimental study was planned to investigate the beneficial effects of Lactobacillus acidophilus and epidermal growth factor (EGF) for CDAD management. Methods: Among 10 groups of BALB/c mice (6 in each), group 1 served as controls receiving no inoculum. Animals in groups 2-10 received C. difficile, those in groups 3, 6 and 9 received L. acidophilus and those in groups 4, 7 and 10 received EGF after C. difficile inoculation. Animals in groups 5-7 were pre-treated with ampicillin and those in groups 8-10 with lansoprazole prior to C. difficile. The animals were killed and investigated for colonisation by C. difficile and toxin production, myeloperoxidase (MPO) activity and histopathology. Results: Colonisation by C. difficile was found to be significantly different (P<0.001) in the various groups. C. difficile toxin titres and MPO activity were significantly lower in animals given L. acidophilus and EGF after ampicillin (groups 6 and 7) and lansoprazole (groups 9 and 10). The severity of acute inflammation was also significantly less (P<0.05) in caecal and colonic segments of animals in groups 6 and 7 compared to those in group 5. Although the severity of acute inflammation was less in the caecal and colonic segment of animals in groups 9 and 10, the reduction was not significant compared to group 8. Interpretation & conclusions: Our findings showed that the administration of L. acidophilus and EGF reduced the severity of C. difficile infection in the experimental animals. PMID:21537099

  13. Microencapsulation of Bifidobacterium animalis subsp. lactis and Lactobacillus acidophilus in cocoa butter using spray chilling technology

    PubMed Central

    Pedroso, D.L.; Dogenski, M.; Thomazini, M.; Heinemann, R.J.B.; Favaro-Trindade, C.S.

    2013-01-01

    In the present study, the cells of Bifidobacterium animalis subsp. lactis (BI-01) and Lactobacillus acidophilus (LAC-04) were encapsulated in cocoa butter using spray-chilling technology. Survival assays were conducted to evaluate the resistance of the probiotics to the spray-chilling process, their resistance to the simulated gastric and intestinal fluids (SGF and SIF), and their stability during 90 days of storage. The viability of the cells was not affected by microencapsulation. The free and encapsulated cells of B. animalis subsp. lactis were resistant to both SGF and SIF. The micro-encapsulated cells of L. acidophilus were more resistant to SGF and SIF than the free cells; the viability of the encapsulated cells was enhanced by 67%, while the free cells reached the detection limit of the method (103 CFU/g). The encapsulated probiotics were unstable when they were stored at 20 °C. The population of encapsulated L. acidophilus decreased drastically when they were stored at 7 °C; only 20% of cells were viable after 90 days of storage. The percentage of viable cells of the encapsulated B. animalis subsp.lactis, however, was 72% after the same period of storage. Promising results were obtained when the microparticles were stored at −18 °C; the freeze granted 90 days of shelf life to the encapsulated cells. These results suggest that the spray-chilling process using cocoa butter as carrier protects L. acidophilus from gastrointestinal fluids. However, the viability of the cells during storage must be improved. PMID:24516445

  14. Microencapsulation of Bifidobacterium animalis subsp. lactis and Lactobacillus acidophilus in cocoa butter using spray chilling technology.

    PubMed

    Pedroso, D L; Dogenski, M; Thomazini, M; Heinemann, R J B; Favaro-Trindade, C S

    2013-01-01

    In the present study, the cells of Bifidobacterium animalis subsp. lactis (BI-01) and Lactobacillus acidophilus (LAC-04) were encapsulated in cocoa butter using spray-chilling technology. Survival assays were conducted to evaluate the resistance of the probiotics to the spray-chilling process, their resistance to the simulated gastric and intestinal fluids (SGF and SIF), and their stability during 90 days of storage. The viability of the cells was not affected by microencapsulation. The free and encapsulated cells of B. animalis subsp. lactis were resistant to both SGF and SIF. The micro-encapsulated cells of L. acidophilus were more resistant to SGF and SIF than the free cells; the viability of the encapsulated cells was enhanced by 67%, while the free cells reached the detection limit of the method (10(3) CFU/g). The encapsulated probiotics were unstable when they were stored at 20 °C. The population of encapsulated L. acidophilus decreased drastically when they were stored at 7 °C; only 20% of cells were viable after 90 days of storage. The percentage of viable cells of the encapsulated B. animalis subsp.lactis, however, was 72% after the same period of storage. Promising results were obtained when the microparticles were stored at -18 °C; the freeze granted 90 days of shelf life to the encapsulated cells. These results suggest that the spray-chilling process using cocoa butter as carrier protects L. acidophilus from gastrointestinal fluids. However, the viability of the cells during storage must be improved.

  15. Stability of free and encapsulated Lactobacillus acidophilus ATCC 4356 in yogurt and in an artificial human gastric digestion system.

    PubMed

    Ortakci, F; Sert, S

    2012-12-01

    The objective of this study was to determine the effect of encapsulation on survival of probiotic Lactobacillus acidophilus ATCC 4356 (ATCC 4356) in yogurt and during artificial gastric digestion. Strain ATCC 4356 was added to yogurt either encapsulated in calcium alginate or in free form (unencapsulated) at levels of 8.26 and 9.47 log cfu/g, respectively, and the influence of alginate capsules (1.5 to 2.5mm) on the sensorial characteristics of yogurts was investigated. The ATCC 4356 strain was introduced into an artificial gastric solution consisting of 0.08 N HCl (pH 1.5) containing 0.2% NaCl or into artificial bile juice consisting of 1.2% bile salts in de Man, Rogosa, and Sharpe broth to determine the stability of the probiotic bacteria. When incubated for 2h in artificial gastric juice, the free ATCC 4356 did not survive (reduction of >7 log cfu/g). We observed, however, greater survival of encapsulated ATCC 4356, with a reduction of only 3 log cfu/g. Incubation in artificial bile juice (6 h) did not significantly affect the viability of free or encapsulated ATCC 4356. Moreover, statistically significant reductions (~1 log cfu/g) of both free and encapsulated ATCC 4356 were observed during 4-wk refrigerated storage of yogurts. The addition of probiotic cultures in free or alginate-encapsulated form did not significantly affect appearance/color or flavor/odor of the yogurts. However, significant deficiencies were found in body/texture of yogurts containing encapsulated ATCC 4356. We concluded that incorporation of free and encapsulated probiotic bacteria did not substantially change the overall sensory properties of yogurts, and encapsulation in alginate using the extrusion method greatly enhanced the survival of probiotic bacteria against an artificial human gastric digestive system.

  16. Potential probiotic lactic acid bacteria Lactobacillus rhamnosus (HN001), Lactobacillus acidophilus (HN017) and Bifidobacterium lactis (HN019) do not degrade gastric mucin in vitro.

    PubMed

    Zhou, J S; Gopal, P K; Gill, H S

    2001-01-22

    The mucus layer (mucin) coating the surface of the gastrointestinal tract (GIT) plays an important role in the mucosal barrier system. Any damage or disturbance of this mucin layer will compromise the host's mucosal defence function. In the present study, the ability of three potential probiotic lactic acid bacteria (LAB) strains (Lactobacillus rhamnosus HN001, Lactobacillus acidophilus HN017, Bifidobacterium lactis HN019) to degrade mucin in vitro was evaluated, in order to assess their potential pathogenicity and local toxicity. The LAB strains were incubated in medium containing hog gastric mucin (HGM, 0.3%) at 37 degrees C for 48 h, following which any decrease in carbohydrate and protein concentration in the ethanol-precipitated portion of the culture medium was determined, using phenol-sulphuric acid and bicinchonic acid (BCA) protein assays, respectively. The change in molecular weight of mucin glycoproteins, following incubation with the test strains, was monitored by SDS-polyacrylamide gel electrophoresis (SDS-PAGE). In order to expose any ability of the test strains to degrade mucin visually and more directly, the test strains were also cultured on agarose containing 0.3% HGM and incubated anaerobically for 72 h at 37 degrees C. No significant change in the carbohydrate or protein concentration in mucin substrates was found following incubation with the test strains. No mucin fragments were derived from the mucin suspension incubated with test strains, and no mucinolysis zone was identified on agarose. These results demonstrate that the potential probiotic LAB strains tested here were unable to degrade gastrointestinal mucin in vitro, which suggests that these novel probiotic candidates are likely to be non-invasive and non-toxic at the mucosal interface.

  17. Functional and comparative genomic analyses of an operon involved in fructooligosaccharide utilization by Lactobacillus acidophilus

    PubMed Central

    Barrangou, Rodolphe; Altermann, Eric; Hutkins, Robert; Cano, Raul; Klaenhammer, Todd R.

    2003-01-01

    Lactobacillus acidophilus is a probiotic organism that displays the ability to use prebiotic compounds such as fructooligosaccharides (FOS), which stimulate the growth of beneficial commensals in the gastrointestinal tract. However, little is known about the mechanisms and genes involved in FOS utilization by Lactobacillus species. Analysis of the L. acidophilus NCFM genome revealed an msm locus composed of a transcriptional regulator of the LacI family, a four-component ATP-binding cassette (ABC) transport system, a fructosidase, and a sucrose phosphorylase. Transcriptional analysis of this operon demonstrated that gene expression was induced by sucrose and FOS but not by glucose or fructose, suggesting some specificity for nonreadily fermentable sugars. Additionally, expression was repressed by glucose but not by fructose, suggesting catabolite repression via two cre-like sequences identified in the promoter–operator region. Insertional inactivation of the genes encoding the ABC transporter substrate-binding protein and the fructosidase reduced the ability of the mutants to grow on FOS. Comparative analysis of gene architecture within this cluster revealed a high degree of synteny with operons in Streptococcus mutans and Streptococcus pneumoniae. However, the association between a fructosidase and an ABC transporter is unusual and may be specific to L. acidophilus. This is a description of a previously undescribed gene locus involved in transport and catabolism of FOS compounds, which can promote competition of beneficial microorganisms in the human gastrointestinal tract. PMID:12847288

  18. Tailoring gut immune responses with lipoteichoic acid-deficient Lactobacillus acidophilus

    PubMed Central

    Lightfoot, Yaíma L.; Mohamadzadeh, Mansour

    2013-01-01

    As highlighted by the development of intestinal autoinflammatory disorders when tolerance is lost, homeostatic interactions between gut microbiota, resident immune cells, and the gut epithelium are key in the maintenance of gastrointestinal health. Gut immune responses, whether stimulatory or regulatory, are dictated by the activated dendritic cells (DCs) that first interact with microorganisms and their gene products to then elicit T and B cell responses. Previously, we have demonstrated that treatment with genetically modified Lactobacillus acidophilus is sufficient to tilt the immune balance from proinflammatory to regulatory in experimental models of colitis and colon cancer. Given the significant role of DCs in efficiently orchestrating intestinal immune responses, characterization of the signals induced within these cells by the surface layer molecules, such as lipoteichoic acid (LTA), and proteins of L. acidophilus is critical for future treatment and prevention of gastrointestinal diseases. Here, we discuss the potential regulatory pathways involved in the downregulation of pathogenic inflammation in the gut, and explore questions regarding the immune responses to LTA-deficient L. acidophilus that require future studies. PMID:23390423

  19. Whole-cell detection of live lactobacillus acidophilus on aptamer-decorated porous silicon biosensors.

    PubMed

    Urmann, K; Arshavsky-Graham, S; Walter, J G; Scheper, T; Segal, E

    2016-09-21

    This work describes the design of optical aptamer-based porous silicon (PSi) biosensors for the direct capture of Lactobacillus acidophilus. Aptamers are oligonucleotides (single-stranded DNA or RNA) that can bind their targets with high affinity and specificity, making them excellent recognition elements for biosensing applications. Herein, aptamer Hemag1P, which specifically targets the important probiotic L. acidophilus, was utilized for direct bacteria capture onto oxidized PSi Fabry-Pérot thin films. Monitoring changes in the reflectivity spectrum (using reflective interferometric Fourier transform spectroscopy) allows for bacteria detection in a label-free, simple and rapid manner. The performance of the biosensor was optimized by tuning the PSi nanostructure, its optical properties, as well as the immobilization density of the aptamer. We demonstrate the high selectivity and specificity of this simple "direct-capture" biosensing scheme and show its ability to distinguish between live and dead bacteria. The resulting biosensor presents a robust and rapid method for the specific detection of live L. acidophilus at concentrations relevant for probiotic products and as low as 10(6) cells per mL. Rapid monitoring of probiotic bacteria is crucial for quality, purity and safety control as the use of probiotics in functional foods and pharmaceuticals is becoming increasingly popular.

  20. Effect of porous starch concentrations on the microbiological characteristics of microencapsulated Lactobacillus acidophilus.

    PubMed

    Xing, Yage; Xu, Qinglian; Ma, Yuan; Che, Zhenming; Cai, Yimin; Jiang, Li

    2014-05-01

    This study was conducted to evaluate the effect of different porous starch concentrations on the microbiological characteristics of microencapsulated Lactobacillus acidophilus. Results showed that the encapsulation efficiency of L. acidophilus with porous starch at a concentration of 10% is the highest (61.2%) compared with other concentrations. The morphology of microencapsulation was observed by scanning electron microscope. Moreover, survival assays at pH 1.5 indicated that, at the end of 3 h, the cell numbers for microencapsulation with 10% porous starch and free cells showed 2.63 and 4.01 logarithmic cycle reductions, respectively. However, no significant reduction in viable count was observed in microcapsules as well as for free cells at pH 6.5 for 3 h. The improving survival rate under high temperatures was observed with increasing concentration of porous starch from 6 to 10% and decreasing temperature. The released counts were increased with prolonged incubation time and were between 6.34 and 6.46 log CFU g(-1) at the end of storage exposure for 2.5 h to simulated colonic pH solution. These results indicated that porous starch with the optimum concentration as a carrier can be considered as an innovative technology to improve the stability of L. acidophilus.

  1. Effects of penicillin G on morphology and certain physiological parameters of Lactobacillus acidophilus ATCC 4356.

    PubMed

    Khaleghi, M; Kasra Kermanshahi, R; Zarkesh-Esfahani, S H

    2011-08-01

    Evidence shows that probiotic bacteria can undergo substantial structural and morphological changes in response to environmental stresses, including antibiotics. Therefore, this study investigated the effects of penicillin G (0.015, 0.03, and 0.06 mg/l) on the morphology and adhesion of Lactobacillus acidophilus ATCC 4356, including the colony morphotype, biofilm production, hydrophobicity, H₂O₂ formation, S-layer structure, and slpA gene expression. Whereas only smooth colonies grew in the presence of penicillin, rough and smooth colony types were observed in the control group. L. acidophilus ATCC 4356 was found to be hydrophobic under normal conditions, yet its hydrophobicity decreased in the presence of the antibiotic. No biofilm was produced by the bacterium, despite testing a variety of different culture conditions; however, treatment with penicillin G (0.015-0.06 mg/l) significantly decreased its production of H₂O₂ formation and altered the S-layer protein structure and slpA gene expression. The S-protein expression decreased with 0.015 mg/l penicillin G, yet increased with 0.03 and 0.06 mg/l penicillin G. In addition, the slpA gene expression decreased in the presence of 0.015 mg/l of the antibiotic. In conclusion, penicillin G was able to alter the S-layer protein production, slpA gene expression, and certain physicochemical properties of Lactobacillus acidophilus ATCC 4356.

  2. Preparation and application characteristics of microencapsulated Lactobacillus acidophilus as probiotics for dogs.

    PubMed

    Ma, Yuan; Xing, Yage; Xu, Qinglian; Wang, TinXuan; Cai, Yimin; Cao, Dong; Che, Zhengming

    2015-01-01

    In this article, preparation and application characteristics of microencapsulated Lactobacillus acidophilus were investigated. Results indicated that the optimum condition for preparation of micro encapsulation were 10% (w/v) wall material and the temperature of 20°C, respectively. Many micropores in the porous starch micro particles was also observed by Scanning Electron Microscope. Furthermore, the released cell counts were increase from 2.43 log cfu/g to 9.17 log cfu/g for the time prolong to 3h in the simulated colonic pH solution. On the other hand, the visible cells of Lactobacillus acidophilus in the dog feces on the 10th day after the probiotics feeding was improve about 34.8% compare to the before feeding, which was decrease about 24.6%for Escherichia coli. Furthermore, the content of is ovaleric acid, indole and 3-methylindole, putrefactive substances in dog feces, before feeding were reduce 24%, 16% and 45% in dog feces on the 10th day after feeding compared to that before feeding, respectively. Micro encapsulation can be considered a useful technology to provide the protection for Lactobacillus acidophilus and better application effective.

  3. Plasma membrane Toll-like receptor activation increases bacterial uptake but abrogates endosomal Lactobacillus acidophilus induction of interferon-β.

    PubMed

    Boye, Louise; Welsby, Iain; Lund, Lisbeth Drozd; Goriely, Stanislas; Frøkiaer, Hanne

    2016-11-01

    Lactobacillus acidophilus induces a potent interferon-β (IFN-β) response in dendritic cells (DCs) by a Toll-like receptor 2 (TLR2) -dependent mechanism, in turn leading to strong interleukin-12 (IL-12) production. In the present study, we investigated the involvement of different types of endocytosis in the L. acidophilus-induced IFN-β and IL-12 responses and how TLR2 or TLR4 ligation by lipopolysaccharide and Pam3/4CSK4 influenced endocytosis of L. acidophilus and the induced IFN-β and IL-12 production. Lactobacillus acidophilus was endocytosed by constitutive macropinocytosis taking place in the immature cells as well as by spleen tyrosine kinase (Syk) -dependent phagocytosis but without involvement of plasma membrane TLR2. Stimulation with TLR2 or TLR4 ligands increased macropinocytosis in a Syk-independent manner. As a consequence, incubation of DCs with TLR ligands before incubation with L. acidophilus enhanced the uptake of the bacteria. However, in these experimental conditions, induction of IFN-β and IL-12 was strongly inhibited. As L. acidophilus-induced IFN-β depends on endocytosis and endosomal degradation before signalling and as TLR stimulation from the plasma membrane leading to increased macropinocytosis abrogates IFN-β induction we conclude that plasma membrane TLR stimulation leading to increased macropinocytosis decreases endosomal induction of IFN-β and speculate that this is due to competition between compartments for molecules involved in the signal pathways. In summary, endosomal signalling by L. acidophilus that leads to IFN-β and IL-12 production is inhibited by TLR stimulation from the plasma membrane.

  4. Lactobacillus casei and Lactobacillus acidophilus regulate inflammatory pathway and improve antioxidant status in collagen-induced arthritic rats.

    PubMed

    Amdekar, Sarika; Singh, Vinod; Kumar, Avnish; Sharma, Poonam; Singh, Rambir

    2013-01-01

    In view of well-established immunomodulatory properties of Lactobacillus, present investigation was carried out to evaluate antioxidant and anti-inflammatory potential of Lactobacillus casei and Lactobacillus acidophilus, against inflammatory pathway and oxidative stress developed in an experimental model of arthritis. Collagen-induced arthritis (CIA) model was used. Oral administration of L. casei, L. acidophilus, standard antiarthritic drug indomethacin, and vehicle were started after induced arthritis and continued up to day 28. Interleukin (IL)-6, tumor necrosis factor (TNF)-α, IL-1β, IL-17, IL-4, and IL-10 levels were estimated in serum. In parallel, oxidative stress parameters were also measured from synovial effsuate. All rats were graded for arthritis score at the end of each week. L. casei, L. acidophilus, and indomethacin treatment significantly downregulated proinflammatory and upregulated anti-inflammatory cytokines at P<0.0001. They have significantly decreased oxidative stress in synovial effsuate (P<0.0001) and also arthritis score (P<0.05). Protection provided by L. casei and L. acidophilus was more pronounced than that of indomethacin. These lines of evidence suggest that L. casei and L. acidophilus exert potent protective effect against CIA. It further establishes effective anti-inflammatory and antioxidant properties of Lactobacillus. However, additional clinical investigations are needed to prove the efficacy of Lactobacillus in treatment/management of rheumatoid arthritis.

  5. Lactobacillus acidophilus K301 Inhibits Atherogenesis via Induction of 24 (S), 25-Epoxycholesterol-Mediated ABCA1 and ABCG1 Production and Cholesterol Efflux in Macrophages.

    PubMed

    Hong, Yi-Fan; Kim, Hangeun; Kim, Hye Sun; Park, Woo Jung; Kim, Joo-Yun; Chung, Dae Kyun

    2016-01-01

    Lactobacillus acidophilus species are well-known probiotics with the beneficial activity of regulating cholesterol levels. In this study, we showed that L. acidophilus K301 reduced the level of cholesterol through reverse transport in macrophages. L. acidophilus K301 upregulated the mRNA and protein levels of genes such as ATP-binding cassette A1 (ABCA1) and ATP-binding cassette G1 (ABCG1) under the control of liver X receptor (LXR), resulting in increased apoA-I-dependent cholesterol efflux in phorbol 12-myristate 13-acetate (PMA)-differentiated THP-1 cells. L. acidophilus K301 induced both ABCA1 and ABCG1 through the endogenous LXR agonist 24(S), 25-epoxcycholesterol, which is synthesized by intracellular cholesterol synthetic pathways. In vivo studies using L. acidophilus K301-treated ApoE-/- mice showed reduced accumulation of lipoproteins in the arterial lumen. The inhibitory effects of L. acidophilus K301 on accumulation of lipoprotein in atherosclerotic plaques were mediated by the induction of squalene reductase (SQLE) and oxidosqualene cyclase (OSC) and resulted in ABCA1-mediated cholesterol efflux. Taken together, our findings revealed that Lactobacillus acidophilus K301 regulates the expression of genes related to cholesterol reverse transport via the induction of endogenous LXR agonist, suggesting the therapeutic potential of Lactobacillus acidophilus K301 as an anti-atherosclerotic agent.

  6. A new record of Chironomus (Chironomus) acidophilus Keyl (Diptera, Chironomidae) from the Uzon volcanic caldera (Kronotsky Reserve, Kamchatka Peninsula, Russia), its karyotype, ecology and biology.

    PubMed

    Orel, Oksana V; Lobkova, Ludmila E; Zhirov, Sergey V; Petrova, Ninel A

    2015-07-03

    Morphology, cytology, ecology and biology of Holarctic Chironomus (Chironomus) acidophilus Keyl, 1960 (Diptera, Chironomidae) was examined from material collected in the geothermal Vosmerka Lake (pH=2.0-2.5). An illustrated redescription of C. acidophilus is given on the basis of adult males reared from field-collected pupae, and of simultaneously collected larvae. Additional larvae belonging to the pseudothummi-complex were identified as C. acidophilus on the basis of their karyotype. The karyotype of C. acidophilus (2n=8) and detailed mapping of the 4 chromosome arms A, E, D and F are provided. The population of C. acidophilus from Kamchatka was found to be karyologically monomorphic. Information on distribution and ecology of C. acidophilus from Vosmerka Lake (total mineralization 1583.5 mg/l) is also given. Chironomus acidophilus is the only species of aquatic insects recorded in this lake. Lack of competition and a richness of food resources contribute to the high abundance (35161 ind./m2) and biomass (11.342 g/m2) of the larvae of C. acidophilus in Vosmerka Lake.

  7. Helicobacter pylori VacA Suppresses Lactobacillus acidophilus-Induced Interferon Beta Signaling in Macrophages via Alterations in the Endocytic Pathway

    PubMed Central

    Weiss, Gudrun; Forster, Sam; Irving, Aaron; Tate, Michelle; Ferrero, Richard L.; Hertzog, Paul; Frøkiær, Hanne; Kaparakis-Liaskos, Maria

    2013-01-01

    ABSTRACT Helicobacter pylori causes chronic gastritis and avoids elimination by the immune system of the infected host. The commensal bacterium Lactobacillus acidophilus has been suggested to exert beneficial effects as a supplement during H. pylori eradication therapy. In the present study, we applied whole-genome microarray analysis to compare the immune responses induced in murine bone marrow-derived macrophages (BMDMs) stimulated with L. acidophilus, H. pylori, or both bacteria in combination. While L. acidophilus induced a Th1-polarizing response characterized by high expression of interferon beta (IFN-β) and interleukin 12 (IL-12), H. pylori strongly induced the innate cytokines IL-1β and IL-1α. In BMDMs prestimulated with L. acidophilus, H. pylori blocked the expression of L. acidophilus-induced IFN-β and IL-12 and suppressed the expression of key regulators of the Rho, Rac, and Cdc42 GTPases. The inhibition of L. acidophilus-induced IFN-β was independent of H. pylori viability and the virulence factor CagPAI; however, a vacuolating cytotoxin (vacA) mutant was unable to block IFN-β. Confocal microscopy demonstrated that the addition of H. pylori to L. acidophilus-stimulated BMDMs redirects intracellular processing, leading to an accumulation of L. acidophilus in the endosomal and lysosomal compartments. Thus, our findings indicate that H. pylori inhibits the development of a strong Th1-polarizing response in BMDMs stimulated with L. acidophilus by blocking the production of IFN-β in a VacA-dependent manner. We suggest that this abrogation is caused by a redirection of the endocytotic pathway in the processing of L. acidophilus. PMID:23760466

  8. Lactobacillus acidophilus CL1285, Lactobacillus casei LBC80R, and Lactobacillus rhamnosus CLR2 (Bio-K+): Characterization, Manufacture, Mechanisms of Action, and Quality Control of a Specific Probiotic Combination for Primary Prevention of Clostridium difficile Infection.

    PubMed

    Auclair, Julie; Frappier, Martin; Millette, Mathieu

    2015-05-15

    A specific probiotic formulation composed of Lactobacillus acidophilus CL1285, Lactobacillus casei LBC80R, and Lactobacillus rhamnosus CLR2 (Bio-K+) has been marketed in North America since 1996. The strains and the commercial products have been evaluated for safety, identity, gastrointestinal survival, and stability throughout shelf life. The capacity of both the fermented beverages and the capsules to reduce incidences of antibiotic-associated diarrhea and Clostridium difficile infection (CDI) has been demonstrated in human clinical trials. Individual strains and the finished products have shown antimicrobial activity against C. difficile and toxin A/B neutralization capacity in vitro. The use of this specific probiotic formulation as part of a bundle of preventive measures to control CDI in healthcare settings is discussed.

  9. Enhancement of natural and acquired immunity by Lactobacillus rhamnosus (HN001), Lactobacillus acidophilus (HN017) and Bifidobacterium lactis (HN019).

    PubMed

    Gill, H S; Rutherfurd, K J; Prasad, J; Gopal, P K

    2000-02-01

    Consumption of lactic acid bacteria (LAB) has been suggested to confer a range of health benefits including stimulation of the immune system and increased resistance to malignancy and infectious illness. In the present study, the effects of feeding Lactobacillus rhamnosus (HN001, DR20), Lactobacillus acidophilus (HN017) and Bifidobacterium lactis (HN019, DR10) on in vivo and in vitro indices of natural and acquired immunity in healthy mice were examined. Mice were fed daily with L. rhamnosus, L. acidophilus or B. lactis (10(9) colony forming units) and their immune function was assessed on day 10 or day 28. Supplementation with L. rhamnosus, L. acidophilus or B. lactis resulted in a significant increase in the phagocytic activity of peripheral blood leucocytes and peritoneal macrophages compared with the control mice. The proliferative responses of spleen cells to concanavalin A (a T-cell mitogen) and lipopolysaccharide (a B-cell mitogen) were also significantly enhanced in mice given different LAB. Spleen cells from mice given L. rhamnosus, L. acidophilus or B. lactis also produced significantly higher amounts of interferon-gamma in response to stimulation with concanavalin A than cells from the control mice. LAB feeding had no significant effect on interleukin-4 production by spleen cells or on the percentages of CD4+, CD8+ and CD40+ cells in the blood. The serum antibody responses to orally and systemically administered antigens were also significantly enhanced by supplementation with L. rhamnosus, L. acidophilus or B. lactis. Together, these results suggest that supplementation of the diet with L. rhamnosus (HN001), L. acidophilus (HN017) or B. lactis (HN019) is able to enhance several indices of natural and acquired immunity in healthy mice.

  10. Lactobacillus acidophilus CRL 1014 improved “gut health” in the SHIME® reactor

    PubMed Central

    2013-01-01

    Background How to maintain “gut health” is a goal for scientists throughout the world. Therefore, microbiota management models for testing probiotics, prebiotics, and synbiotics have been developed. Methods The SHIME® model was used to study the effect of Lactobacillus acidophilus 1014 on the fermentation pattern of the colon microbiota. Initially, an inoculum prepared from human feces was introduced into the reactor vessels and stabilized over 2-wk using a culture medium. This stabilization period was followed by a 2-wk control period during which the microbiota was monitored. The microbiota was then subjected to a 4-wk treatment period by adding 5 mL of sterile peptone water with L. acidophilus CRL1014 at the concentration of 108 CFU/mL to vessel one (the stomach compartment). Plate counts, Denaturing Gradient Gel Electrophoresis (DGGE), short-chain fatty acid (SCFA) and ammonium analyses were carried out for monitoring of the microbial community from the colon compartments. Results A significant increase (p < 0.01) in the Lactobacillus spp. and Bifidobacterium spp. populations was observed during the treatment period. The DGGE obtained showed changes in the lactobacilli community from the colon compartments of the SHIME® reactor. The (SCFA) concentration increased (p < 0.01) during the treatment period, due mainly to significant increased levels of acetic, butyric, and propionic acids. However, ammonium concentrations decreased during the same period (p < 0.01). Conclusions This study showed the beneficial influence of L. acidophilus CRL 1014 on microbial metabolism and lactobacilli community composition for improving human health. PMID:23758634

  11. The effect of NaCl substitution with KCl on proteinase activities of cell-free extract and cell-free supernatant at different pH levels and salt concentrations: Lactobacillus acidophilus and Lactobacillus casei.

    PubMed

    Ayyash, M M; Sherkat, F; Shah, N P

    2013-01-01

    The aim of this study was to investigate the effect of substitution of NaCl with KCl at different pH levels and salt concentrations on proteinase activity of cell-free extract and cell-free supernatant of the probiotics Lactobacillus acidophilus and Lactobacillus casei. de Man, Rogosa, and Sharpe broth aliquots were mixed with 2 pure salts (NaCl and KCl) and 2 salt concentrations at 2 concentration levels (5 and 10%), inoculated with Lactobacillus acidophilus or Lactobacillus casei, and incubated aerobically at 37°C for 22 h. The cultures were then centrifuged at 4,000×g for 30 min, and the collected cell pellets were used to prepare cell-wall proteinases and the supernatants used as a source of supernatant (extracellular) proteinases. The proteolytic activity and protein content of both portions were determined. After incubation of both portions with 3 milk caseins (α-, β-, κ-casein), the supernatants were individually subjected to analysis of angiotensin-converting enzyme (ACE)-inhibitory activity and proteolytic activity using the o-phthalaldehyde method. Significant differences were observed in ACE-inhibitory and proteolytic activities between salt substitution treatments of cell-free extract and cell-free supernatant from both probiotic strains at the same salt concentration and pH level.

  12. Characteristic odor components of volatile oil from the cultivation medium of Lactobacillus acidophilus.

    PubMed

    Ono, Toshirou; Yonejima, Yasunori; Ikeda, Atsushi; Kashima, Yusei; Nakaya, Satoshi; Miyazawa, Mitsuo

    2014-01-01

    Volatile oils obtained from both the liquid medium after incubation (MAI) and liquid medium before incubation (MBI) in the cultivation process of Lactobacillus acidophilus were isolated by hydrodistillation (HD) and analyzed to investigate the utility of the liquid waste. The composition of the volatile oils was analyzed by capillary gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). In total, 46 and 19 compounds were detected in the volatile oils from MAI (MAI oil) and MBI (MBI oil), respectively. The principle components of MAI oil were fatty acids, including pentanoic acid (12.75%), heptanoic acid (14.05%), and nonanoic acid (14.04%). The important aroma-active compounds in the oils were detected by GC-MS/Olfactometry (GC-O), and their intensity of aroma were measured by aroma extraction dilution analysis (AEDA). Pyrazines were determined as key aroma components; in particular, 2-ethyl-5-methylpyrazine was the most primary aroma-active compound in MAI oil. In addition, as the characteristic aroma-active compounds, 3-(methylthio)-propanal, trimethylpyrazine, and pentanoic acid were also detected in MAI oil. These results imply that the waste medium after incubation of L. acidophilus may be utilized as a source of volatile oils.

  13. Physicochemical and hygienic effects of Lactobacillus acidophilus in Iranian white cheese

    PubMed Central

    Mahmoudi, Razzaqh; Tajik, Hossein; Ehsani, Ali; Zare, Payman

    2012-01-01

    Increasing incidence of food-borne disease along with its social and economic consequences have led to conducting extensive research in order to produce safer food and develop new antimicrobial agents; among them, extensive use of probiotics and bacteriocins as biological additives is of significant importance. The aim of the present study was to evaluate the interactions (growth behavior and survival) of Listeria monocytogenes and Lactobacillus acidophilus in various stages of production, ripening and storage of Iranian white cheese. Changes in pH values at different stages of cheese ripening, along with changes in organoleptic properties of cheese were also assessed. Compared to other treatments, in the treatment of cheese with probiotic agent without starter, the most significant decrease in Listeria monocytogenes count at the end of ripening stage was observed (3.16 Log per gram cheese compared with the control group) (p < 0.05). Survival of probiotic bacteria in control samples of cheese were significantly higher when compared to cheese sample contaminated with Listeria (p < 0.05). White probiotic cheese with starter had the highest of sensory acceptability (p < 0.05). Listeria Monocytogenes count decreased during ripening period of probiotic white cheese but the bacteria survived in probiotic white cheese. Lactobacillus acidophilus count decreased during ripening period of white cheese but it did not lower to less than 106 CFU per g at the end of ripening and storage periods. PMID:25610568

  14. Transcriptional Analysis of Prebiotic Uptake and Catabolism by Lactobacillus acidophilus NCFM

    PubMed Central

    Andersen, Joakim Mark; Barrangou, Rodolphe; Hachem, Maher Abou; Lahtinen, Sampo J.; Goh, Yong-Jun; Svensson, Birte; Klaenhammer, Todd R.

    2012-01-01

    The human gastrointestinal tract can be positively modulated by dietary supplementation of probiotic bacteria in combination with prebiotic carbohydrates. Here differential transcriptomics and functional genomics were used to identify genes in Lactobacillus acidophilus NCFM involved in the uptake and catabolism of 11 potential prebiotic compounds consisting of α- and β- linked galactosides and glucosides. These oligosaccharides induced genes encoding phosphoenolpyruvate-dependent sugar phosphotransferase systems (PTS), galactoside pentose hexuronide (GPH) permease, and ATP-binding cassette (ABC) transporters. PTS systems were upregulated primarily by di- and tri-saccharides such as cellobiose, isomaltose, isomaltulose, panose and gentiobiose, while ABC transporters were upregulated by raffinose, Polydextrose, and stachyose. A single GPH transporter was induced by lactitol and galactooligosaccharides (GOS). The various transporters were associated with a number of glycoside hydrolases from families 1, 2, 4, 13, 32, 36, 42, and 65, involved in the catabolism of various α- and β-linked glucosides and galactosides. Further subfamily specialization was also observed for different PTS-associated GH1 6-phospho-β-glucosidases implicated in the catabolism of gentiobiose and cellobiose. These findings highlight the broad oligosaccharide metabolic repertoire of L. acidophilus NCFM and establish a platform for selection and screening of both probiotic bacteria and prebiotic compounds that may positively influence the gastrointestinal microbiota. PMID:23028535

  15. Transcriptional analysis of prebiotic uptake and catabolism by Lactobacillus acidophilus NCFM.

    PubMed

    Andersen, Joakim Mark; Barrangou, Rodolphe; Hachem, Maher Abou; Lahtinen, Sampo J; Goh, Yong-Jun; Svensson, Birte; Klaenhammer, Todd R

    2012-01-01

    The human gastrointestinal tract can be positively modulated by dietary supplementation of probiotic bacteria in combination with prebiotic carbohydrates. Here differential transcriptomics and functional genomics were used to identify genes in Lactobacillus acidophilus NCFM involved in the uptake and catabolism of 11 potential prebiotic compounds consisting of α- and β-linked galactosides and glucosides. These oligosaccharides induced genes encoding phosphoenolpyruvate-dependent sugar phosphotransferase systems (PTS), galactoside pentose hexuronide (GPH) permease, and ATP-binding cassette (ABC) transporters. PTS systems were upregulated primarily by di- and tri-saccharides such as cellobiose, isomaltose, isomaltulose, panose and gentiobiose, while ABC transporters were upregulated by raffinose, Polydextrose, and stachyose. A single GPH transporter was induced by lactitol and galactooligosaccharides (GOS). The various transporters were associated with a number of glycoside hydrolases from families 1, 2, 4, 13, 32, 36, 42, and 65, involved in the catabolism of various α- and β-linked glucosides and galactosides. Further subfamily specialization was also observed for different PTS-associated GH1 6-phospho-β-glucosidases implicated in the catabolism of gentiobiose and cellobiose. These findings highlight the broad oligosaccharide metabolic repertoire of L. acidophilus NCFM and establish a platform for selection and screening of both probiotic bacteria and prebiotic compounds that may positively influence the gastrointestinal microbiota.

  16. In situ control of food spoilage fungus using Lactobacillus acidophilus NCDC 291.

    PubMed

    Garcha, Seema; Natt, Navdeep Kaur

    2012-10-01

    A challenge for food industry today is to produce minimally processed food, without use of chemical preservatives and little compromise on nutritional status. Lactobacillus acidophilus NCDC 291 can be directly added to food where it enhances shelf life by competing with other microflora (both bacterial and fungal) for food and also by production of antimicrobial metabolites as bacteriocins. Comprehensive studies have demonstrated the in vitro activity of bacteriocins. However their role in preventing fresh food spoilage needs more elucidation. The present study was conducted to evaluate the efficacy of the whole cells of this organism as biopreservative agent against fungi. Four most commonly occurring spoilage fungi were isolated and were identified as Fusarium, Alternaria, Penicillium and Aspergillus. Growth of all of them was inhibited in in vitro studies, (approximately 33-43% decrease in mycelial dry weight basis between test and control). In situ biopreservation of Indian cheese and raw poultry meat was attempted and the colony count of Alternaria was significantly (p < 0.05, Bonferroni Holm) reduced in presence of L. acidophilus. Dip and Keep approach of preservation for Mangifera and Momordica were carried out in which microbial spoilage was not observed up to 6 days.

  17. A functional glycogen biosynthesis pathway in Lactobacillus acidophilus: expression and analysis of the glg operon.

    PubMed

    Goh, Yong Jun; Klaenhammer, Todd R

    2013-09-01

    Glycogen metabolism contributes to energy storage and various physiological functions in some prokaryotes, including colonization persistence. A role for glycogen metabolism is proposed on the survival and fitness of Lactobacillus acidophilus, a probiotic microbe, in the human gastrointestinal environment. L. acidophilus NCFM possesses a glycogen metabolism (glg) operon consisting of glgBCDAP-amy-pgm genes. Expression of the glg operon and glycogen accumulation were carbon source- and growth phase-dependent, and were repressed by glucose. The highest intracellular glycogen content was observed in early log-phase cells grown on trehalose, which was followed by a drastic decrease of glycogen content prior to entering stationary phase. In raffinose-grown cells, however, glycogen accumulation gradually declined following early log phase and was maintained at stable levels throughout stationary phase. Raffinose also induced an overall higher temporal glg expression throughout growth compared with trehalose. Isogenic ΔglgA (glycogen synthase) and ΔglgB (glycogen-branching enzyme) mutants are glycogen-deficient and exhibited growth defects on raffinose. The latter observation suggests a reciprocal relationship between glycogen synthesis and raffinose metabolism. Deletion of glgB or glgP (glycogen phosphorylase) resulted in defective growth and increased bile sensitivity. The data indicate that glycogen metabolism is involved in growth maintenance, bile tolerance and complex carbohydrate utilization in L. acidophilus.

  18. Potentiated anti-microsporidial activity of Lactobacillus acidophilus CH1 bacteriocin using gold nanoparticles.

    PubMed

    Mossallam, Shereen F; Amer, Eglal I; Diab, Radwa G

    2014-09-01

    Through increased awareness and improved diagnostics, microsporidiosis has now been identified in a broader range of human populations; however current therapies are inconsistently effective. Recently, probiotics were determined as means for the control of intestinal parasitic infections through their secretory products; bacteriocins. This is the first study on the effect of bacteriocin produced by Lactobacillus acidophilus CH1 bacteriocin, with or without gold nanoparticles (Au-NPs), against intestinal microsporidiosis in immunosuppressed mice. Fecal and intestinal spore loads, besides viability, extrusion and infectivity of spores from treated animals were assessed. Results showed that the anti-microsporidial effects of bacteriocin were significantly potent. This efficiency was further potentiated upon conjugating bacteriocins with Au-NPs, as it induced a strikingly sustained reduction in fecal spore shedding after cessation of therapy by 1 week (94.26%). Furthermore, reduction in intestinal spore load was highest in bacteriocin/Au-NPs-inoculated mice (89.7%) followed by bacteriocin-inoculated group (73.5%). Spores encountered from stool of bacteriocin/Au-NPs group showed 92.4% viability, versus 93.7% in bacteriocin group. Spore extrusion and infectivity were most inhibited by exposure to bacteriocin/Au-NPs. Safety of bacteriocin/Au-NPs was also verified. Thus, considering the results of the present work, L. acidophilus CH1-derived bacteriocin can present a powerful safe therapy against intestinal microsporidiosis.

  19. Insights into glycogen metabolism in Lactobacillus acidophilus: impact on carbohydrate metabolism, stress tolerance and gut retention.

    PubMed

    Goh, Yong Jun; Klaenhammer, Todd R

    2014-11-20

    In prokaryotic species equipped with glycogen metabolism machinery, the co-regulation of glycogen biosynthesis and degradation has been associated with the synthesis of energy storage compounds and various crucial physiological functions, including global cellular processes such as carbon and nitrogen metabolism, energy sensing and production, stress response and cell-cell communication. In addition, the glycogen metabolic pathway was proposed to serve as a carbon capacitor that regulates downstream carbon fluxes, and in some microorganisms the ability to synthesize intracellular glycogen has been implicated in host persistence. Among lactobacilli, complete glycogen metabolic pathway genes are present only in select species predominantly associated with mammalian hosts or natural environments. This observation highlights the potential involvement of glycogen biosynthesis in probiotic activities and persistence of intestinal lactobacilli in the human gastrointestinal tract. In this review, we summarize recent findings on (i) the presence and potential ecological distribution of glycogen metabolic pathways among lactobacilli, (ii) influence of carbon substrates and growth phases on glycogen metabolic gene expression and glycogen accumulation in L. acidophilus, and (iii) the involvement of glycogen metabolism on growth, sugar utilization and bile tolerance. Our present in vivo studies established the significance of glycogen biosynthesis on the competitive retention of L. acidophilus in the mouse intestinal tract, demonstrating for the first time that the ability to synthesize intracellular glycogen contributes to gut fitness and retention among probiotic microorganisms.

  20. Control of cell morphology of probiotic Lactobacillus acidophilus for enhanced cell stability during industrial processing.

    PubMed

    Senz, Martin; van Lengerich, Bernhard; Bader, Johannes; Stahl, Ulf

    2015-01-02

    The viability of bacteria during industrial processing is an essential quality criterion for bacterial preparations, such as probiotics and starter cultures. Therefore, producing stable microbial cultures during proliferation is of great interest. A strong correlation between the culture medium and cellular morphology was observed for the lactic acid bacterium Lactobacillus acidophilus NCFM, which is commonly used in the dairy industry as a probiotic supplement and as a starter culture. The cell shapes ranged from single short rods to long filamentous rods. The culture medium composition could control this phenomenon of pleomorphism, especially the use of peptone in combination with an adequate heating of the medium during preparation. Furthermore, we observed a correlation between the cell size and stability of the microorganisms during industrial processing steps, such as freeze-drying, extrusion encapsulation and storage following dried preparations. The results revealed that short cells are more stable than long cells during each of the industrially relevant processing steps. As demonstrated for L. acidophilus NCFM, the adaptation of the medium composition and optimized medium preparation offer the possibility to increase the concentration of viable cells during up- and survival rate during down-stream processing.

  1. Lactobacillus acidophilus ameliorates H. pylori-induced gastric inflammation by inactivating the Smad7 and NFκB pathways

    PubMed Central

    2012-01-01

    Background H. pylori infection may trigger Smad7 and NFκB expression in the stomach, whereas probiotics promote gastrointestinal health and improve intestinal inflammation caused by pathogens. This study examines if probiotics can improve H. pylori-induced gastric inflammation by inactivating the Smad7 and NFκB pathways. Results Challenge with H. pylori increased IL-8 and TNF-α expressions but not TGF-β1 in MKN45 cells. The RNA levels of Smad7 in AGS cells increased after H. pylori infection in a dose-dependent manner. A higher dose (MOI 100) of L. acidophilus pre-treatment attenuated the H. pylori-induced IL-8 expressions, but not TGF-β1. Such anti-inflammatory effect was mediated via increased cytoplasmic IκBα and depletion of nuclear NFκB. L. acidophilus also inhibited H. pylori-induced Smad7 transcription by inactivating the Jak1 and Stat1 pathways, which might activate the TGF-β1/Smad pathway. L. acidophilus pre-treatment ameliorated IFN-γ-induced Smad7 translation level and subsequently reduced nuclear NF-κB production, as detected by western blotting. Conclusions H. pylori infection induces Smad7, NFκB, IL-8, and TNF-α production in vitro. Higher doses of L. acidophilus pre-treatment reduce H. pylori-induced inflammation through the inactivation of the Smad7 and NFκB pathways. PMID:22429929

  2. Supplementation with a Lactobacillus acidophilus fermentation product alters the metabolic response following a lipopolysaccharide challenge in weaned pigs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study was designed to determine if feeding a Lactobacillus acidophilus fermentation product to weaned pigs would alter the metabolic response following a lipopolysaccharide (LPS) challenge. Pigs (n=30; 6.4+/-0.1 kg BW) were housed individually with ad libitum access to feed and water. Pigs were...

  3. Supplementation of Lactobacillus acidophilus fermentation product can attenuate the acute phase response following a lipopolysaccharide challenge in pigs.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study was designed to determine if feeding a Lactobacillus acidophilus fermentation product to weaned pigs would reduce stress and acute phase responses (APR) following a lipopolysaccharide (LPS) challenge. Pigs (n=30; 6.4±0.1 kilograms body weight) were housed individually in pens with ad libi...

  4. Cost effectiveness of cryoprotective agents and modified De-man Rogosa Sharpe medium on growth of Lactobacillus acidophilus.

    PubMed

    Pyar, Hassan; Peh, Kok-Khiang

    2014-04-01

    The effect of cryoprotective agents (namely, sodium chloride, sucrose, dextran, sorbitol, monosodium glutamate, glycerol, skim milk and skim milk with malt extract) and modified De-Man Rogosa Sharpe (MRS) medium, on the viability and stability of L. acidophilus ATCC 4962, was investigated. The modified MRS medium was not only economical, but it gave a relatively higher yield of L. acidophilus ATCC 4962 than the commercial MRS. Monosodium glutamate, skim milk and skim milk with malt extract provided significantly higher viable counts, with optimum concentration at 0.3%. Nevertheless, at concentration above 0.5%, there was a reduction in cell viability, which could be attributed to cell shrinkage associated with osmotic pressure changes inside the cells. It was also found that L. acidophilus ATCC 4962 was stable at 28 degrees C for eight weeks. Skim milk demonstrated a significant growth of probiotics. Skim milk was the preferred cryoprotective agent, as it is of low cost, easily available and demonstrated a significant growth of probiotics. In conclusion, modified MRS medium with skim milk is suggested for the remarkable growth and yield of L. acidophilus.

  5. High dose and low dose Lactobacilli acidophilus exerted differential immune modulating effects on T cell immune responses induced by an oral human rotavirus vaccine in gnotobiotic pigs

    PubMed Central

    Wen, Ke; Li, Guohua; Bui, Tammy; Liu, Fangning; Li, Yanru; Kocher, Jacob; Lin, Lin; Yang, Xingdong; Yuan, Lijuan

    2011-01-01

    Background Strain-specific effects of probiotics in pro- or anti-inflammatory immune responses have been well recognized. Several proinflammatory Lactobacillus strains have been shown to act as adjuvants to enhance the immunogenicity of vaccines. However, dose effects of probiotics in modulating immune responses are not clearly understood. This study examined the dose effects of Lactobacillus acidophilus (LA) NCFM strain on T cell immune responses to rotavirus vaccination in a gnotobiotic (Gn) pig model. Methods Frequencies of IFN-γ producing CD4+ and CD8+ T cell and IL-10 and TGF-β producing CD4+CD25+ and CD4+CD25- regulatory T (Treg) cell responses were determined in the intestinal and systemic lymphoid tissues of Gn pigs vaccinated with an oral human rotavirus vaccine in conjunction with low dose (5 feedings; up to 106 colony forming units [CFU]/dose) or high dose (14 feedings; up to 109 CFU/dose) or without LA feeding. Results Low dose LA significantly promoted IFN-γ producing T cell responses and down-regulated Treg cell responses and their TGF-β and IL-10 productions in all the tissues compared to the high dose LA and control groups. To the contrary, high dose LA increased the frequencies of Treg cells in most of the tissues compared to the control groups. The dose effects of LA on IFN-γ producing T cell and CD4+CD25- Treg cell immune responses were similar in the intestinal and systemic lymphoid tissues and were independent from the vaccination. Conclusion Thus the same probiotic strain in different doses can either promote or suppress IFN-γ producing T cell or Treg cell immune responses. These findings have significant implications in the use of probiotic lactobacilli as immunostimulatory versus immunoregulatory agents. Probiotics can be ineffective or even detrimental if not used at the optimal dosage for the appropriate purposes. PMID:22178726

  6. Influence of the Probiotic Lactobacillus acidophilus NCFM
and Lactobacillus rhamnosus HN001 on Proteolysis Patterns
of Edam Cheese

    PubMed Central

    Cichosz, Grażyna; Nalepa, Beata; Kowalska, Marika

    2014-01-01

    Summary The objective of this study is to determine the viability of Lactobacillus acidophilus NCFM and Lactobacillus rhamnosus HN001 in Edam cheese as well as the effect of probiotic bacteria on paracasein proteolysis and changes in the water activity during ripening. The use of probiotics L. rhamnosus HN001 and L. acidophilus NCFM in Edam cheese slightly changed its chemical composition, but the change was not significant. The pH values were significantly correlated with the changes in Lactobacillus count (R=–0.807) and the level of phosphotungstic acid-soluble nitrogen compounds in total nitrogen (PTA-SN/TN) (R=0.775). After 10 weeks of ripening, the highest level of trichloroacetic acid-soluble nitrogen compounds in total nitrogen (TCA-SN/TN) was observed in the cheese containing L. rhamnosus HN001 (11.87%) and slightly lower level in the cheese containing L. acidophilus NCFM (7.60%) and control cheese (6.24%). The highest level of PTA-SN/TN fraction was noted in cheese containing L. acidophilus NCFM (3.48%) but the lowest level was observed in control cheese (2.24%) after ten weeks of ripening. The changes in the levels of PTA-SN/TN (R=–0.813) and TCA-SN/TN (R=–0.717) fractions were significantly (p<0.05) correlated with the viability of probiotic counts. Water activity (aw) strongly correlated with the PTA-SN/TN level (R=–0.824) and bacteria viability (R=–0.728). All of the analyzed cheeses were characterized by high counts of L. rhamnosus HN001 and L. acidophilus NCFM during ten weeks of ripening. PMID:27904317

  7. Microencapsulation of Lactobacillus acidophilus La-5 by spray-drying using sweet whey and skim milk as encapsulating materials.

    PubMed

    Maciel, G M; Chaves, K S; Grosso, C R F; Gigante, M L

    2014-01-01

    The aim of this study was to evaluate the effect of encapsulating material on encapsulation yield, resistance to passage through simulated gastrointestinal conditions, and viability of Lactobacillus acidophilus La-5 during storage. Microparticles were produced from reconstituted sweet whey or skim milk (30% total solids) inoculated with a suspension of L. acidophilus La-5 (1% vol/vol) and subjected to spray-drying at inlet and outlet temperatures of 180°C and 85 to 95°C, respectively. The samples were packed, vacuum-sealed, and stored at 4°C and 25°C. Encapsulation yield, moisture content, and resistance of microencapsulated L. acidophilus La-5 compared with free cells (control) during exposure to in vitro gastrointestinal conditions (pH 2.0 and 7.0) were evaluated. Viability was assessed after 0, 7, 15, 30, 45, 60, and 90d of storage. The experiments were repeated 3 times and data were analyzed by ANOVA and Tukey test for the comparison between means. The encapsulating material did not significantly affect encapsulation yield, average diameter, or moisture of the particles, which averaged 76.58±4.72%, 12.94±0.78μm, and 4.53±0.32%, respectively. Both microparticle types were effective in protecting the probiotic during gastrointestinal simulation, and the skim milk microparticles favored an increase in viability of L. acidophilus La-5. Regardless of the encapsulating material and temperature of storage, viability of the microencapsulated L. acidophilus La-5 decreased on average 0.43 log cfu/g at the end of 90d of storage, remaining higher than 10(6)cfu/g.

  8. Effects of encapsulated Lactobacillus acidophilus along with pasteurized longan juice on the colon microbiota residing in a dynamic simulator of the human intestinal microbial ecosystem.

    PubMed

    Chaikham, Pittaya; Apichartsrangkoon, Arunee

    2014-01-01

    The effect of encapsulated Lactobacillus acidophilus LA5 along with pasteurized longan juice on the colon microbiota was investigated by applying a dynamic model of the human gastrointestinal tract. Encapsulated L. acidophilus LA5 in pasteurized longan juice or sole encapsulated L. acidophilus LA5 exhibited the efficiency of colonizing the colon and enabling the growth of colon lactobacilli as well as beneficial bifidobacteria but inhibited the growth of fecal coliforms and clostridia. Moreover, these treatments gave rise to a significant increase of lactic acid and short-chain fatty acids such as acetate, propionate, and butyrate. Although acetate displayed the highest quantity, it was likely that after incorporating encapsulated L. acidophilus LA5 plus pasteurized longan juice, quantity of butyrate exceed propionate, and acetate in comparison with their controls. Denaturant gradient gel electrophoresis patterns confirmed that various treatments affected the alteration of microbial community within the simulator of the human intestinal microbial ecosystem.

  9. Helicobacter pylori VacA suppresses Lactobacillus acidophilus-induced interferon beta signaling in macrophages via alterations in the endocytic pathway.

    PubMed

    Weiss, Gudrun; Forster, Sam; Irving, Aaron; Tate, Michelle; Ferrero, Richard L; Hertzog, Paul; Frøkiær, Hanne; Kaparakis-Liaskos, Maria

    2013-06-11

    Helicobacter pylori causes chronic gastritis and avoids elimination by the immune system of the infected host. The commensal bacterium Lactobacillus acidophilus has been suggested to exert beneficial effects as a supplement during H. pylori eradication therapy. In the present study, we applied whole-genome microarray analysis to compare the immune responses induced in murine bone marrow-derived macrophages (BMDMs) stimulated with L. acidophilus, H. pylori, or both bacteria in combination. While L. acidophilus induced a Th1-polarizing response characterized by high expression of interferon beta (IFN-β) and interleukin 12 (IL-12), H. pylori strongly induced the innate cytokines IL-1β and IL-1α. In BMDMs prestimulated with L. acidophilus, H. pylori blocked the expression of L. acidophilus-induced IFN-β and IL-12 and suppressed the expression of key regulators of the Rho, Rac, and Cdc42 GTPases. The inhibition of L. acidophilus-induced IFN-β was independent of H. pylori viability and the virulence factor CagPAI; however, a vacuolating cytotoxin (vacA) mutant was unable to block IFN-β. Confocal microscopy demonstrated that the addition of H. pylori to L. acidophilus-stimulated BMDMs redirects intracellular processing, leading to an accumulation of L. acidophilus in the endosomal and lysosomal compartments. Thus, our findings indicate that H. pylori inhibits the development of a strong Th1-polarizing response in BMDMs stimulated with L. acidophilus by blocking the production of IFN-β in a VacA-dependent manner. We suggest that this abrogation is caused by a redirection of the endocytotic pathway in the processing of L. acidophilus. IMPORTANCE Approximately half of the world's population is infected with Helicobacter pylori. The factors that allow this pathogen to persist in the stomach and cause chronic infections have not yet been fully elucidated. In particular, how H. pylori avoids killing by macrophages, one of the main types of immune cell underlying the

  10. Lactobacillus acidophilus modulates inflammatory activity by regulating the TLR4 and NF-κB expression in porcine peripheral blood mononuclear cells after lipopolysaccharide challenge.

    PubMed

    Lee, Sang In; Kim, Hyun Soo; Koo, Jin Mo; Kim, In Ho

    2016-02-28

    A total of forty weaned pigs ((Landrace × Yorkshire) × Duroc) were used to evaluate the effects of Lactobacillus acidophilus on inflammatory activity after lipopolysaccharide (LPS) challenge. Experimental treatments were as follows: (T1) control diet+saline challenge; (T2) control diet with 0·1% L. acidophilus+saline challenge; (T3) control diet+LPS challenge; and (T4) control diet with 0·1% L. acidophilus+LPS challenge. On d-14, piglets were challenged with saline (T1 and T2) or LPS (T3 and T4). Blood samples were obtained at 0, 2, 4, 6 and 12 h after being challenged and analysed for immune cell cytokine production and gene expression pattern. The L. acidophilus treatment increased the average daily weight gain (ADWG) and average daily feed intake (ADFI) compared with the control diet. With the control diet, the LPS challenge (T3) increased the number of immune cells and expression of TNF-α and IL-6 compared with the saline challenge (T1). Whereas with the saline challenge L. acidophilus treatment (T2) increased the number of leucocytes and CD4 compared with the control diet (T1), with the LPS challenge L. acidophilus treatment (T4) decreased the number of leucocytes, lymphocytes, CD4+ and CD8+ and expression of TNF-α and IL-6 compared with the control diet (T3). L. acidophilus treatment decreased the expression of TRL4 and NF-κB in peripheral blood mononuclear cells (PBMC) after LPS challenge, which leads to inhibition of TNF-α, IFN-γ, IL-6, IL-8 and IL1B1 and to induction of IL-4 and IL-10. We suggested that L. acidophilus improved ADWG and ADFI and protected against LPS-induced inflammatory responses by regulating TLR4 and NF-κB expression in porcine PBMC.

  11. Viricidal effect of Lactobacillus acidophilus on human immunodeficiency virus type 1: possible role in heterosexual transmission

    PubMed Central

    1991-01-01

    Peroxidase, H2O2, and a halide form a powerful antimicrobial system in phagocytes and tissue fluids, and certain microorganisms can serve as the source of H2O2 for this system. H2O2-generating Lactobacillus acidophilus (LB+) is present in the vagina of most normal women and peroxidase has been detected in vaginal fluid. LB+ at high concentration is viricidal to HIV-1, and, at levels where LB+ is ineffective alone, the addition of peroxidase (myeloperoxidase, eosinophil peroxidase) and a halide (chloride, iodide, bromide, thiocyanate) restore viricidal activity. LB+ can be replaced by H2O2, but not by non-H2O2-producing LB, and viricidal activity is inhibited by azide and catalase. The survival of HIV in the female genital tract and thus the likelihood of transmission may be influenced by the activity of the LB(+)-peroxidase-halide system in the vagina. PMID:1647436

  12. Cofactor-induced reversible folding of Flavodoxin-4 from Lactobacillus acidophilus

    PubMed Central

    Dutta, Samit Kumar; Serrano, Pedro; Geralt, Michael; Axelrod, Herbert L; Xu, Qingping; Lesley, Scott A; Godzik, Adam; Deacon, Ashley M; Elsliger, Marc-André; Wilson, Ian A; Wüthrich, Kurt

    2015-01-01

    Flavodoxins in combination with the flavin mononucleotide (FMN) cofactor play important roles for electron transport in prokaryotes. Here, novel insights into the FMN-binding mechanism to flavodoxins-4 were obtained from the NMR structures of the apo-protein from Lactobacillus acidophilus (YP_193882.1) and comparison of its complex with FMN. Extensive reversible conformational changes were observed upon FMN binding and release. The NMR structure of the FMN complex is in agreement with the crystal structure (PDB ID: 3EDO) and exhibits the characteristic flavodoxin fold, with a central five-stranded parallel β–sheet and five α-helices forming an α/β-sandwich architecture. The structure differs from other flavoproteins in that helix α2 is oriented perpendicular to the β-sheet and covers the FMN-binding site. This helix reversibly unfolds upon removal of the FMN ligand, which represents a unique structural rearrangement among flavodoxins. PMID:26177955

  13. Purification and some properties of acidocin 8912, a novel bacteriocin produced by Lactobacillus acidophilus TK8912.

    PubMed

    Tahara, T; Kanatani, K; Yoshida, K; Miura, H; Sakamoto, M; Oshimura, M

    1992-08-01

    Acidocin 8912, a bacteriocin produced by Lactobacillus acidophilus TK8912, was purified by ammonium sulfate fractionation and successive chromatographies on CM-cellulose, Sephadex G-50, Sephadex G-25, and reversed-phase HPLC on Aquapore RP-300. The purified acidocin 8912 migrated as a single band on SDS-PAGE. The molecular weight was estimated to be 5200 by SDS-PAGE, and 5400 by HPLC gel filtration on TSKgel G3000PWXL. Both the amino acid composition and the N-terminal amino acid sequence analysis indicated that acidocin 8912 was a peptide composed of presumably 50 amino acids containing a Lys residue at the N-terminus. The purified acidocin 8912 showed a bactericidal effect on sensitive cells but not a bacteriolytic effect.

  14. Optimization of Lactobacillus acidophilus cultivation using taro waste and evaluation of its biological activity.

    PubMed

    Hsieh, Shu-Chen; Liu, Jui-Ming; Pua, Xiao-Hui; Ting, Yuwen; Hsu, Ren-Jun; Cheng, Kuan-Chen

    2016-03-01

    In this study, taro waste (TW) was utilized for Lactobacillus acidophilus BCRC 14079 cultivation and the anti-tumor and immune-modulatory properties of heat-killed cells (HKCs), cytoplasmic fraction (CF), and exopolysaccharide (EPS) were evaluated. The optimum liquefaction enzyme dosage, temperature, and time determined by Box-Behnken design response surface methodology (BBD-RSM) were 9 mL/L of α-amylase, 79.2 °C, and 5 h of reaction, respectively. The optimum temperature and reaction time for saccharification were determined as 60 °C and 3 h. The optimum medium, CGMY1 medium, constitutes of TW hydrolysate containing 37 g/L of glucose, 25 g/L of corn gluten meal (CGM), and 1 g/L of yeast extract (YE). Results of MTT assay showed that HKCs and EPS from CGM medium exhibited the highest anti-proliferative in HT-29 (IC50 of HKCs, 467.25 μg/mL; EPS, 716.10 μg/mL) and in Caco-2 cells (IC50 of EPS, 741.60 μg/mL). Luciferase-based NF-ΚB and COX-2 systems indicated HKCs from CGM medium stimulated the highest expression of luciferin in both systems. The luciferase activities by using 100 and 500 μg/mL of HKCs from CGM were 24.30- and 45.83-fold in NF-ΚB system and 11.54- and 4.93-fold in COX-2 system higher than the control. In conclusion, this study demonstrated the potential of TW medium for L. acidophilus cultivation and the production of non-viable probiotics with enhanced biological activities.

  15. Complete genome sequence of the probiotic lactic acid bacterium Lactobacillus acidophilus NCFM

    PubMed Central

    Altermann, Eric; Russell, W. Michael; Azcarate-Peril, M. Andrea; Barrangou, Rodolphe; Buck, B. Logan; McAuliffe, Olivia; Souther, Nicole; Dobson, Alleson; Duong, Tri; Callanan, Michael; Lick, Sonja; Hamrick, Alice; Cano, Raul; Klaenhammer, Todd R.

    2005-01-01

    Lactobacillus acidophilus NCFM is a probiotic bacterium that has been produced commercially since 1972. The complete genome is 1,993,564 nt and devoid of plasmids. The average GC content is 34.71% with 1,864 predicted ORFs, of which 72.5% were functionally classified. Nine phage-related integrases were predicted, but no complete prophages were found. However, three unique regions designated as potential autonomous units (PAUs) were identified. These units resemble a unique structure and bear characteristics of both plasmids and phages. Analysis of the three PAUs revealed the presence of two R/M systems and a prophage maintenance system killer protein. A spacers interspersed direct repeat locus containing 32 nearly perfect 29-bp repeats was discovered and may provide a unique molecular signature for this organism. In silico analyses predicted 17 transposase genes and a chromosomal locus for lactacin B, a class II bacteriocin. Several mucus- and fibronectin-binding proteins, implicated in adhesion to human intestinal cells, were also identified. Gene clusters for transport of a diverse group of carbohydrates, including fructooligosaccharides and raffinose, were present and often accompanied by transcriptional regulators of the lacI family. For protein degradation and peptide utilization, the organism encoded 20 putative peptidases, homologs for PrtP and PrtM, and two complete oligopeptide transport systems. Nine two-component regulatory systems were predicted, some associated with determinants implicated in bacteriocin production and acid tolerance. Collectively, these features within the genome sequence of L. acidophilus are likely to contribute to the organisms' gastric survival and promote interactions with the intestinal mucosa and microbiota. PMID:15671160

  16. Protection of Lactobacillus acidophilus NRRL-B 4495 under in vitro gastrointestinal conditions with whey protein/pullulan microcapsules.

    PubMed

    Çabuk, Burcu; Tellioğlu Harsa, Şebnem

    2015-12-01

    In this research, whey protein/pullulan (WP/pullulan) microcapsules were developed in order to assess its protective effect on the viability of Lactobacillus acidophilus NRRL-B 4495 under in vitro gastrointestinal conditions. Results demonstrated that WP/pullulan microencapsulated cells exhibited significantly (p ≤ 0.05) higher resistance to simulated gastric acid and bile salt. Pullulan incorporation into protein wall matrix resulted in improved survival as compared to free cells after 3 h incubation in simulated gastric solution. Moreover WP/pullulan microcapsules were found to release over 70% of encapsulated L. acidophilus NRRL-B 4495 cells within 1 h. The effect of encapsulation during refrigerated storage was also studied. Free bacteria exhibited 3.96 log reduction while, WP/pullulan encapsulated bacteria showed 1.64 log reduction after 4 weeks of storage.

  17. Some low homogenization pressures improve certain probiotic characteristics of yogurt culture bacteria and Lactobacillus acidophilus LA-K.

    PubMed

    Muramalla, T; Aryana, K J

    2011-08-01

    Lactobacillus delbrueckii ssp. bulgaricus, Streptococcus salivarius ssp. thermophilus, and Lactobacillus acidophilus are dairy cultures widely used in the manufacture of cultured dairy products. Commonly used homogenization pressures in the dairy industry are 13.80 MPa or less. It is not known whether low homogenization pressures can stimulate bacteria to improve their probiotic characteristics. Objectives were to determine the effect of homogenization at 0, 3.45, 6.90, 10.34, and 13.80 MPa on acid tolerance, bile tolerance, protease activity, and growth of L. delbrueckii ssp. bulgaricus LB-12, S. salivarius ssp. thermophilus ST-M5, and L. acidophilus LA-K. The cultures were individually inoculated in cool autoclaved skim milk (4°C) and homogenized for 5 continuous passes. Growth and bile tolerance of samples were determined hourly for 10h of incubation. Acid tolerance was determined every 20 min for 120 min of incubation. Protease activity was determined at 0, 12, and 24h of incubation. All homogenization pressures studied improved acid tolerance of L. delbrueckii ssp. bulgaricus LB-12 but had no beneficial effect on protease activity and had negative effects on growth and bile tolerance. A pressure of 6.90 MPa improved acid tolerance, bile tolerance, and protease activity of S. salivarius ssp. thermophilus ST-M5, but none of the homogenization pressures studied had an effect on its growth. Homogenization pressures of 13.80 and 6.90 MPa improved acid tolerance and bile tolerance, respectively, of L. acidophilus LA-K but had no effect on protease activity and its growth. Some low homogenization pressures positively influenced some characteristics of yogurt culture bacteria and L. acidophilus LA-K. Culture pretreatment with some low homogenization pressures can be recommended for improvement of certain probiotic characteristics.

  18. Transcriptional and functional analysis of oxalyl-coenzyme A (CoA) decarboxylase and formyl-CoA transferase genes from Lactobacillus acidophilus.

    PubMed

    Azcarate-Peril, M Andrea; Bruno-Bárcena, Jose M; Hassan, Hosni M; Klaenhammer, Todd R

    2006-03-01

    Oxalic acid is found in dietary sources (such as coffee, tea, and chocolate) or is produced by the intestinal microflora from metabolic precursors, like ascorbic acid. In the human intestine, oxalate may combine with calcium, sodium, magnesium, or potassium to form less soluble salts, which can cause pathological disorders such as hyperoxaluria, urolithiasis, and renal failure in humans. In this study, an operon containing genes homologous to a formyl coenzyme A transferase gene (frc) and an oxalyl coenzyme A decarboxylase gene (oxc) was identified in the genome of the probiotic bacterium Lactobacillus acidophilus. Physiological analysis of a mutant harboring a deleted version of the frc gene confirmed that frc expression specifically improves survival in the presence of oxalic acid at pH 3.5 compared with the survival of the wild-type strain. Moreover, the frc mutant was unable to degrade oxalate. These genes, which have not previously been described in lactobacilli, appear to be responsible for oxalate degradation in this organism. Transcriptional analysis using cDNA microarrays and reverse transcription-quantitative PCR revealed that mildly acidic conditions were a prerequisite for frc and oxc transcription. As a consequence, oxalate-dependent induction of these genes occurred only in cells first adapted to subinhibitory concentrations of oxalate and then exposed to pH 5.5. Where genome information was available, other lactic acid bacteria were screened for frc and oxc genes. With the exception of Lactobacillus gasseri and Bifidobacterium lactis, none of the other strains harbored genes for oxalate utilization.

  19. Dual functions of Lactobacillus acidophilus NCFM™ at the intermediate dose in protection against rotavirus diarrhea in gnotobiotic pigs vaccinated with a human rotavirus vaccine

    PubMed Central

    Liu, Fangning; Wen, Ke; Li, Guohua; Yang, Xingdong; Kocher, Jacob; Bui, Tammy; Jones, Dorothy; Pelzer, Kevin; Clark-Deener, Sherrie; Yuan, Lijuan

    2014-01-01

    Objectives To examine dose effects of Lactobacillus acidophilus NCFM (LA) ™ strain on rotavirus-specific antibody and B cell responses in gnotobiotic pigs vaccinated with an oral attenuated human rotavirus (AttHRV). Methods Pigs were inoculated with AttHRV vaccine in conjunction with high dose LA (14 doses, total 2.2×109 colony forming units [CFU]), intermediate dose LA (9 doses, total 3.2×106 CFU), low dose LA (5 doses, total 2.1×106 CFU) or without LA feeding. Protection against rotavirus shedding and diarrhea was assessed upon challenge with a virulent HRV. Rotavirus-specific IgA and IgG antibodies in serum and rotavirus-specific IgA and IgG antibody-secreting cells (ASC) and memory B cells in ileum, spleen and blood of the pigs were measured and compared among treatment groups. Results The intermediate dose LA (MidLA), but not high or low dose LA, significantly reduced rotavirus diarrhea (MidLA only group) and significantly improved the protection conferred by AttHRV vaccine (MidLA+AttHRV group). Associated with the increased protection, MidLA significantly enhanced rotavirus-specific antibody, ASC and memory B cell responses to AttHRV vaccine. High or low dose LA did not enhance virus-specific antibody and ASC responses, hence did not improve the vaccine efficacy. Conclusions These findings highlight the importance of dose selection and indicate that certain specific lactobacilli strains at the appropriate dose have the dual function of reducing rotavirus diarrhea and enhancing the immunogenicity and protective efficacy of rotavirus vaccines. PMID:24126832

  20. Viability of Lactobacillus acidophilus in synbiotic guava mousses and its survival under in vitro simulated gastrointestinal conditions.

    PubMed

    Buriti, Flávia C A; Castro, Inar A; Saad, Susana M I

    2010-02-28

    The effects of refrigeration, freezing and substitution of milk fat by inulin and whey protein concentrate (WPC) on Lactobacillus acidophilus La-5 viability and resistance to gastric and enteric simulated conditions in synbiotic guava mousses effects were investigated. Refrigerated mousses supplemented with WPC presented the best probiotic viability, ranging from 7.77 to 6.24 log cfu/g during 28 days of storage. The highest probiotic populations, above 7.45 log cfu/g, were observed for all frozen mousses during 112 days of storage. Decreased L. acidophilus survival during the in vitro gastrointestinal simulation was observed both for refrigerated and frozen mousses. Nonetheless, for the refrigerated mousses, the addition of inulin enhanced the probiotic survival during the in vitro assays in the first week of storage. L. acidophilus survival in simulated gastrointestinal fluids was also improved through freezing. The frozen storage may be used to provide increased shelf-life for synbiotic guava mousses. Even though the protective effect of inulin and WPC on the probiotic microorganism tested was shown to be more specific for the refrigerated products, the partial replacement of milk fat by these ingredients may also help, as it improves the nutritional value of mousses in both storage conditions.

  1. Antibiotic susceptibility profiles of new probiotic Lactobacillus and Bifidobacterium strains.

    PubMed

    Zhou, J S; Pillidge, C J; Gopal, P K; Gill, H S

    2005-02-01

    The antimicrobial susceptibilities and presence of plasmids in four new probiotic lactic acid bacteria (LAB) strains, Lactobacillus rhamnosus HN001 (DR20) HN067, Lactobacillus acidophilus HN017 and Bifidobacterium lactis HN019 (DR10), were determined. Resistance to 18 commonly used antibiotics was assessed by disk diffusion. The three Lactobacillus strains had similar antibiotic susceptibility profiles to those of Lactobacillus plantarum strain HN045 and two commercial probiotic Lactobacillus strains, GG and LA-1. The B. lactis strain HN019 had a similar profile to three commercial probiotic B. lactis strains (Bb12, HN049 and HN098). All 10 strains were sensitive to the Gram-positive spectrum antibiotics erythromycin and novobiocin, the broad-spectrum antibiotics rifampicin, spectinomycin, tetracycline and chloramphenicol and the beta-lactam antibiotics penicillin, ampicillin and cephalothin. By contrast, most strains were resistant to the Gram-negative spectrum antibiotics fusidic acid, nalidixic acid and polymyxin B and the aminoglycosides neomycin, gentamicin, kanamycin and streptomycin. All three L. rhamnosus strains (HN001, HN067 and GG) were resistant to vancomycin and several strains were also resistant to cloxacillin. Of the four new probiotic strains, only L. rhamnosus HN001 contained plasmids; however, a plasmid-free derivative of HN001 had the same antibiotic susceptibility profile as the parent strain.

  2. Effect of Lactobacillus acidophilus and Bifidobacterium bifidum supplementation to standard triple therapy on Helicobacter pylori eradication and dynamic changes in intestinal flora.

    PubMed

    Wang, Yu-huan; Huang, Ying

    2014-03-01

    To investigate Lactobacillus acidophilus (L. acidophilus) and Bifidobacterium bifidum (B. bifidum) supplementation to triple therapy for Helicobacter pylori (H. pylori) eradication and dynamic changes in intestinal flora in children with H. pylori infection. One hundred H. pylori-infected children were randomly assigned to two groups: treatment group (n = 43), standard triple anti-H. pylori therapy plus probiotics of L. acidophilus and B. bifidum for 2 weeks followed by taking probiotics for another 4 weeks; control group (n = 45), standard triple anti-H. pylori therapy for 6 weeks. After 6-week treatment, ¹³C-urease breath test was performed and side effects were monitored during the observation period. Quantitative PCR with 16S rRNA-gene-targeted species-specific primers was carried out for the analysis of human intestinal B. bifidum, L. acidophilus, and Escherichia coli (E. coli). As expected, treatment group could significantly enhance the H. pylori eradication rate (83.7 vs. 64.4 %, P < 0.05). B. bifidum, L. acidophilus, and E. coli showed no statistical difference before or after therapy in the treatment group. The number of B. bifidum and L. acidophilus was significantly decreased after 2-week treatment in the control group, but after 6-week treatment it significantly increased and nearly returned to the level before treatment. The number of E. coli increased significantly after 2-week treatment, while after 6-week treatment, it nearly decreased to the level before treatment. L. acidophilus and B. bifidum supplementation is effective for H. pylori eradication compared with triple therapy alone.

  3. Newly Identified Thermostable Esterase from Sulfobacillus acidophilus: Properties and Performance in Phthalate Ester Degradation

    PubMed Central

    Zhang, Xiao-Yan; Fan, Xiang; Qiu, Yong-Jun; Li, Cheng-Yuan; Xing, Shuai; Zheng, Yi-Tao

    2014-01-01

    EstS1, a newly identified thermostable esterase from Sulfobacillus acidophilus DSM10332, was heterologously expressed in Escherichia coli and shown to enzymatically degrade phthalate esters (PAEs) to their corresponding monoalkyl PAEs. The optimal pH and temperature of the esterase were found to be 8.0 and 70°C, respectively. The half-life of EstS1 at 60°C was 15 h, indicating that the enzyme had good thermostability. The specificity constant (kcat/Km) of the enzyme for p-nitrophenyl butyrate was as high as 6,770 mM−1 s−1. The potential value of EstS1 was demonstrated by its ability to effectively hydrolyze 35 to 82% of PAEs (10 mM) within 2 min at 37°C, with all substrates being completely degraded within 24 h. At 60°C, the time required for complete hydrolysis of most PAEs was reduced by half. To our knowledge, this enzyme is a new esterase identified from thermophiles that is able to degrade various PAEs at high temperatures. PMID:25149523

  4. Preparation and characterization of alginate and psyllium beads containing Lactobacillus acidophilus.

    PubMed

    Lotfipour, Farzaneh; Mirzaeei, Shahla; Maghsoodi, Maryam

    2012-01-01

    This paper describes preparation and characterization of beads of alginate and psyllium containing probiotic bacteria of Lactobacillus acidophilus DMSZ20079. Twelve different formulations containing alginate (ALG) and alginate-psyllium (ALG-PSL) were prepared using extrusion technique. The prepared beads were characterized in terms of size, morphology and surface properties, encapsulation efficiency, viabilities in acid (pH 1.8, 2 hours) and bile (0.5% w/v, 2 hours) conditions, and release in simulated colon pH conditions. The results showed that spherical beads with narrow size distribution ranging from 1.59 ± 0.04 to 1.67 ± 0.09 mm for ALG and from 1.61 ± 0.06 to 1.80 ± 0.07 mm for ALG-PSL with encapsulation efficiency higher than 98% were achieved. Furthermore, addition of PSL into ALG enhanced the integrity of prepared beads in comparison with ALG formulations. The results indicated that incorporation of PSL into alginate beads improved viability of the bacteria in acidic conditions as well as bile conditions. Also, stimulating effect of PSL on the probiotic bacteria was observed through 20-hour incubation in simulated colonic pH solution. According to our in vitro studies, PSL can be a suitable polymer candidate for partial substitution with ALG for probiotic coating.

  5. Effect of spermicides on Lactobacillus acidophilus in vitro-nonoxynol-9 vs. Sapindus saponins.

    PubMed

    Ojha, P; Maikhuri, J P; Gupta, G

    2003-08-01

    Saponins extracted from the fruit pericarp of Sapindus mukorosii were tested for their bactericidal/bacteriostatic property against Lactobacillus acidophilus. Nonoxynol-9 was used as a reference compound for the comparison of activity. Lactobacillus colonies were grown on specific medium (Rogosa SL agar) containing different concentrations of saponins and nonoxynol-9 in an atmosphere of 5% CO2/95% air at 37 degrees C for 72 h. The number and size of colonies were recorded at the end of the experiment and compared with controls. Results indicated that nearly 90% of Lactobacillus colonies with minor reduction in size thrived at 0.05% concentration of saponins whereas only 18% of colonies with approximately 75% reduction in size grew in dishes containing 0.05% nonoxynol-9. At higher concentrations of saponins, there was a gradual, dose-dependent reduction in the number and size of colonies and at 2.5% concentration there was an approximately 55% reduction in the number and 60% reduction in the size of surviving colonies. No lactobacillus colonies, however, grew in dishes containing 0.1% and higher concentrations of nonoxynol-9. The studies indicate that Sapindus saponins as compared to nonoxynol-9 are far less toxic to lactobacillus species and therefore saponins containing spermicidal preparations are likely to be more vaginal-friendly than equivalent nonoxynol-9 preparations.

  6. Synbiotic yogurt-ice cream produced via incorporation of microencapsulated lactobacillus acidophilus (la-5) and fructooligosaccharide.

    PubMed

    Ahmadi, Abbas; Milani, Elnaz; Madadlou, Ashkan; Mortazavi, Seyed Ali; Mokarram, Reza Rezaei; Salarbashi, Davoud

    2014-08-01

    Yogurt-ice cream is a nutritious product with a refreshing taste and durability profoundly longer than that of yogurt. The probiotic Lactobacillus acidophilus (La-5) cells either in free or encapsulated form were incorporated into yog-ice cream and their survivability were studied. Fructooligosaccharide (FOS) as a prebiotic compound at three levels (0, 4 & 8 % w/w) was added to yogurt-ice cream mix and its effects on some chemical properties, overrun and firmness of product were evaluated. The higher the incorporated FOS concentration, the lower were the pH value and higher the total solid content of treatments. FOS incorporation (8 %) significantly increased the overrun of treatments and reduced their firmness. The viable counts of free probiotics decreased from ~9.55 to ~7.3 log cfu/g after 60 days of frozen storage while that of encapsulated cells merely decreased less than 1 log cycle. Encapsulation with alginate microbeads protected the probiotic cells against injuries in the freezing stage as well as, during frozen storage.

  7. Cloning, expression and characterization of a mucin-binding GAPDH from Lactobacillus acidophilus.

    PubMed

    Patel, Dhaval K; Shah, Kunal R; Pappachan, Anju; Gupta, Sarita; Singh, Desh Deepak

    2016-10-01

    Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is a ubiquitous enzyme involved in glycolysis. It is also referred to as a moonlighting protein as it has many diverse functions like regulation of apoptosis, iron homeostasis, cell-matrix interactions, adherence to human colon etc. apart from its principal role in glycolysis. Lactobacilli are lactic acid bacteria which colonize the human gut and confer various health benefits to humans. In the present study, we have cloned, expressed and purified the GAPDH from Lactobacillus acidophilus to get a recombinant product (r-LaGAPDH) and characterized it. Size exclusion chromatography shows that r-LaGAPDH exists as a tetramer in solution and have a mucin binding and hemagglutination activity indicating carbohydrate like binding adhesion mechanism. Fluorescence spectroscopy studies showed an interaction of r-LaGAPDH with mannose, galactose, N-acetylgalactosamine and N-acetylglucosamine with a Kd of 3.6±0.7×10(-3)M, 4.34±0.09×10(-3)M, 4±0.87×10(-3)M and 3.7±0.28×10(-3)M respectively. We hope that this preliminary data will generate more interest in further elucidation of the roles of GAPDH in the adhesion processes of the bacteria.

  8. Effect of moderate electric field frequency on growth kinetics and metabolic activity of Lactobacillus acidophilus.

    PubMed

    Loghavi, Laleh; Sastry, Sudhir K; Yousef, Ahmed E

    2008-01-01

    Moderate electric fields (MEF) have been previously shown to alter the metabolic activity of microbial cells; thus, the effect of frequency and electric field would be of considerable interest. We investigated herein the effects of MEF frequency on microbial growth kinetics and bacteriocin (Lacidin A) production of Lactobacillus acidophilus OSU 133 during fermentation. The following fermentation treatments were compared: conventional (for 40 h), MEF (1 V cm(-1), for 40 h), combination of MEF (1 V cm(-1), for the first 5 h) and conventional (for 35 h) at various frequency levels (45, 60, and 90 Hz) all at 30 degrees C, and control (conventional) fermentation at 37 degrees C. MEF treatments with purely sinusoidal waveforms at all frequencies at 30 degrees C produced a shorter lag phase than conventional fermentation. However, no lag phase reduction was found for a 60 Hz waveform that contained high-frequency harmonics. There was, however, a significant increase in the bacteriocin production under early MEF treatment at 60 Hz with high-frequency harmonics. On the basis of these observations, the fermentation process is accelerated by applying pure sinusoidal MEF at the early stage of growth while a significant increase in the bacteriocin production occurs when sinusoidal field at 60 Hz with harmonics is applied at the early stage of the growth.

  9. Preparation and Characterization of Alginate and Psyllium Beads Containing Lactobacillus acidophilus

    PubMed Central

    Lotfipour, Farzaneh; Mirzaeei, Shahla; Maghsoodi, Maryam

    2012-01-01

    This paper describes preparation and characterization of beads of alginate and psyllium containing probiotic bacteria of Lactobacillus acidophilus DMSZ20079. Twelve different formulations containing alginate (ALG) and alginate-psyllium (ALG-PSL) were prepared using extrusion technique. The prepared beads were characterized in terms of size, morphology and surface properties, encapsulation efficiency, viabilities in acid (pH 1.8, 2 hours) and bile (0.5% w/v, 2 hours) conditions, and release in simulated colon pH conditions. The results showed that spherical beads with narrow size distribution ranging from 1.59 ± 0.04 to 1.67 ± 0.09 mm for ALG and from 1.61 ± 0.06 to 1.80 ± 0.07 mm for ALG-PSL with encapsulation efficiency higher than 98% were achieved. Furthermore, addition of PSL into ALG enhanced the integrity of prepared beads in comparison with ALG formulations. The results indicated that incorporation of PSL into alginate beads improved viability of the bacteria in acidic conditions as well as bile conditions. Also, stimulating effect of PSL on the probiotic bacteria was observed through 20-hour incubation in simulated colonic pH solution. According to our in vitro studies, PSL can be a suitable polymer candidate for partial substitution with ALG for probiotic coating. PMID:22649306

  10. Estimation of the potential antitumor activity of microencapsulated Lactobacillus acidophilus yogurt formulation in the attenuation of tumorigenesis in Apc(Min/+) mice.

    PubMed

    Urbanska, Aleksandra Malgorzata; Bhathena, Jasmine; Martoni, Christopher; Prakash, Satya

    2009-02-01

    There is a strong correlation between orally administered probiotics and suppression of the low-grade inflammation that can lead to restoration of normal local immune functions. We studied the potential immunomodulatory and antitumorigenic properties of microencapsulated probiotic bacterial cells in a yogurt formulation in Min mice carrying a germline APC mutation. Daily oral administration of microencapsulated Lactobacillus acidophilus bacterial cells in the yogurt formulation mice resulted in significant suppression of colon tumor incidence, tumor multiplicity, and reduced tumor size. Results show that oral administration of microencapsulated L. acidophilus contributed to the stabilization of animal body weight and decreased the release of bile acids. Histopathological analyses revealed fewer adenomas in treated versus untreated animals. Furthermore, treated animals exhibited fewer gastrointestinal intra-epithelial neoplasias with a lower grade of dysplasia in detected tumors. Results suggest that oral administration of microencapsulated probiotic L. acidophilus exerts anti-tumorous activity, which consequently leads to reduced tumor outcome.

  11. The Effects of Lactobacillus acidophilus on the Intestinal Smooth Muscle Contraction through PKC/MLCK/MLC Signaling Pathway in TBI Mouse Model.

    PubMed

    Sun, Bo; Hu, Chen; Fang, Huan; Zhu, Lina; Gao, Ning; Zhu, Jingci

    2015-01-01

    Clinical studies have shown that probiotics influence gastrointestinal motility. However, the molecular mechanisms by which probiotic Lactobacillus modulates intestinal motility in traumatic brain injury (TBI) mouse model have not been explored. In the present study, we provided evidence showing that treatment of TBI mice with Lactobacillus acidophilus significantly improved the terminal ileum villus morphology, restored the impaired interstitial cells of Cajal (ICC) and the disrupted ICC networks after TBI, and prevented TBI-mediated inhibition of contractile activity in intestinal smooth muscle. Mechanistically, the decreased concentration of MLCK, phospho-MLC20 and phospho-MYPT1 and increased concentration of MLCP and PKC were observed after TBI, and these events mediated by TBI were efficiently prevented by Lactobacillus acidophilus application. These findings may provide a novel mechanistic basis for the application of Lactobacillus acidophilus in the treatment of TBI.

  12. Enzymology and structure of the GH13_31 glucan 1,6-α-glucosidase that confers isomaltooligosaccharide utilization in the probiotic Lactobacillus acidophilus NCFM.

    PubMed

    Møller, Marie S; Fredslund, Folmer; Majumder, Avishek; Nakai, Hiroyuki; Poulsen, Jens-Christian N; Lo Leggio, Leila; Svensson, Birte; Abou Hachem, Maher

    2012-08-01

    Isomaltooligosaccharides (IMO) have been suggested as promising prebiotics that stimulate the growth of probiotic bacteria. Genomes of probiotic lactobacilli from the acidophilus group, as represented by Lactobacillus acidophilus NCFM, encode α-1,6 glucosidases of the family GH13_31 (glycoside hydrolase family 13 subfamily 31) that confer degradation of IMO. These genes reside frequently within maltooligosaccharide utilization operons, which include an ATP-binding cassette transporter and α-glucan active enzymes, e.g., maltogenic amylases and maltose phosphorylases, and they also occur separated from any carbohydrate transport or catabolism genes on the genomes of some acidophilus complex members, as in L. acidophilus NCFM. Besides the isolated locus encoding a GH13_31 enzyme, the ABC transporter and another GH13 in the maltooligosaccharide operon were induced in response to IMO or maltotetraose, as determined by reverse transcription-PCR (RT-PCR) transcriptional analysis, suggesting coregulation of α-1,6- and α-1,4-glucooligosaccharide utilization loci in L. acidophilus NCFM. The L. acidophilus NCFM GH13_31 (LaGH13_31) was produced recombinantly and shown to be a glucan 1,6-α-glucosidase active on IMO and dextran and product-inhibited by glucose. The catalytic efficiency of LaGH13_31 on dextran and the dextran/panose (trisaccharide) efficiency ratio were the highest reported for this class of enzymes, suggesting higher affinity at distal substrate binding sites. The crystal structure of LaGH13_31 was determined to a resolution of 2.05 Å and revealed additional substrate contacts at the +2 subsite in LaGH13_31 compared to the GH13_31 from Streptococcus mutans (SmGH13_31), providing a possible structural rationale to the relatively high affinity for dextran. A comprehensive phylogenetic and activity motif analysis mapped IMO utilization enzymes from gut microbiota to rationalize preferential utilization of IMO by gut residents.

  13. The effects of Lactobacillus acidophilus as feed supplement on skin mucosal immune parameters, intestinal microbiota, stress resistance and growth performance of black swordtail (Xiphophorus helleri).

    PubMed

    Hoseinifar, Seyed Hossein; Roosta, Zahra; Hajimoradloo, Abdolmajid; Vakili, Farzaneh

    2015-02-01

    The present study evaluates the effects of different levels of dietary Lactobacillus acidophilus as feed supplement on intestinal microbiota, skin mucus immune parameters and salinity stress resistance as well as growth performance of black swordtail (Xiphophorus helleri). One-thousand and eight hundred healthy black swordtail larvae (0.03 ± 0.001 g) were randomly distributed in 12 tanks (100 L) at a density of 150 fish per aquaria and fed different levels of dietary L. acidophilus (0, 1.5 × 10(8), 3 × 10(8) and 6 × 10(8) CFU g(-1)) for 10 weeks. At the end of trial, there were significant differences among antibacterial activity of skin mucus in probiotic fed fish and control group (P < 0.05). Furthermore, the skin mucus protein level and alkaline phosphatase activity in control group were significantly lower than those of L. acidophilus fed fish (P < 0.05). Microbiological assessments revealed that feeding with probiotic supplemented diet remarkably increased total autochthonous bacteria and autochthonous lactic acid bacteria levels (P < 0.05). The results showed that dietary administration of L. acidophilus significantly elevated black swordtail resistance against salinity stress (i.e survival %) (P < 0.05). Also, dietary administration of different levels of L. acidophilus improved weight gain, SGR, FCR compared to fish fed unsupplemented diet (P < 0.05). These results demonstrate beneficial effects of dietary L. acidophilus on mucosal immune parameters, intestinal microbiota, stress resistance and growth parameters of black swordtail and the appropriate inclusion is 6 × 10(8) CFU g(-1).

  14. Effect of aqueous and alcoholic Stevia (Stevia rebaudiana) extracts against Streptococcus mutans and Lactobacillus acidophilus in comparison to chlorhexidine: An in vitro study

    PubMed Central

    Ajagannanavar, Sunil Lingaraj; Shamarao, Supreetha; Battur, Hemant; Tikare, Shreyas; Al-Kheraif, Abdulaziz Abdullah; Al Sayed, Mohammed Sayed Al Esawy

    2014-01-01

    Introduction: Stevia (S. rebaudiana) a herb which has medicinal value and was used in ancient times as a remedy for a great diversity of ailments and sweetener. Leaves of Stevia contain a high concentration of Stevioside and Rebaudioside which are supposed to be sweetening agents. Aim: To compare the efficacy of aqueous and alcoholic S. rebaudiana extract against Streptococcus mutans and Lactobacillus acidophilus in comparison to chlorhexidine. Materials and Methods: In the first part of the study, various concentrations of aqueous and ethanolic Stevia extract were prepared in the laboratory of Pharmacy College. It was then subjected to microbiological assay to determine its zone of inhibition using Agar disk diffusion test and minimum inhibitory concentration (MIC) using serial broth dilution method against Streptococcus mutans and Lactobacillus acidophilus. Chlorhexidine was used as a positive control. One way Analysis of Variance (ANOVA) test was used for multiple group comparisons followed by Tukey post hoc for group wise comparisons. Results: Minimum inhibitory concentration (MIC) of aqueous and ethnolic Stevia extract against Streptococcus mutans and Lactobacillus acidophilus were 25% and 12.5% respectively. Mean zone of inhibition of the aqueous and alcoholic Stevia extracts against Streptococcus mutans at 48 hours were 22.8 mm and 26.7 mm respectively. Mean zone of inhibition of the aqueous and alcoholic Stevia extracts against Lactobacillus acidophilus at 48 hours were 14.4 mm and 15.1 mm respectively. Mean zone of inhibition of the chlorhexidine against Streptococcus mutans and Lactobacillus acidophilus at 48 hours was 20.5 and 13.2 respectively. Conclusion: The inhibitory effect shown by alcoholic Stevia extract against Streptococcus mutans and Lactobacillus acidophilus was superior when compared with that of aqueous form and was inferior when compared with Chlorhexidine. PMID:25558451

  15. Effect of intestinal colonisation by two Lactobacillus strains on the immune response of gnotobiotic mice.

    PubMed

    Steinberg, R S; Lima, M; Gomes de Oliveira, N L; Miyoshi, A; Nicoli, J R; Neumann, E; Nunes, A C

    2014-12-01

    The effect of intestinal colonisation on the immune system was investigated in germ-free mice monoassociated with Lactobacillus strains isolated from calf faeces. Single doses of Lactobacillus acidophilus L36 or Lactobacillus salivarius L38 were administered to germ-free mice by intragastric gavage. Ten days later, the mice were euthanised. Gene expression levels of interleukin 5 (IL-5), IL-6, IL-10, IL-12b, IL-17a, gamma interferon (IFN-γ), transforming growth factor beta 1 (TGF-β1), and tumour necrosis factor alpha (TNF-α) were quantified in segments of the small and large intestines by real time quantitative polymerase chain reaction. All the mice were colonised rapidly after Lactobacillus administration with intestinal counts ranging from 6.53 to 8.26 log cfu/g. L. acidophilus L36 administration increased the expression of cytokines involved with the Th2 (IL-5, IL-6 and TGF-β1) and Th17 (IL-17a, TNF-α and IL-6) inflammatory response, whereas L. salivarius L38 appeared to stimulate a pattern of less diversified cytokines in the intestine. Intragastric gavage of L. acidophilus L36 and L. salivarius L38 induced similar levels of colonisation in the digestive tracts of germ-free mice but stimulated different immune responses in the intestinal mucosa. The different immunomodulation patterns might facilitate the potential use of these lactobacilli as probiotics to treat distinct pathological conditions, for example protection against Citrobacter rodentium infection by stimulating IL-17 production.

  16. Effect of probiotic strains of lacto- and bifidobacteria on the activity of macrophages and other parameters of immunity in cases of staphylococcosis.

    PubMed

    Mokrozub, V V; Lazarenko, L M; Babenko, L P; Shynkarenko-Sichel, L M; Olevinska, Z M; Timoshok, N O; Pidgorskyi, V S; Spivak, M Y

    2012-01-01

    The immunomodulatory properties of Lactobacillus delbrueckii subsp. bulgaricus IMVB-7281, Lactobacillus casei IMV B-7280, Lactobacillus acidophilus IMV B-7279, Bifidobacterium animales VKL and B. animales VKB strains on the models of experimental staphylococcosis infection in mice were determined. It was found that after the mice, infected with staphylococcus, were treated by some probiotic strains of lacto- and bifidobacteria, a normalization of functional activity of phagoctic cells system and increase of the endogenous interferon production were observed. L. delbrueckii subsp. bulgaricus IMVB-7281, L. casei IMVB-7280, L. acidophilus IMV B-7279, B. animales VKB and B. animales VKL are promising for the development of probiotics, effective against staphylococci and for the immunity correction.

  17. A novel biosensor based on Lactobacillus acidophilus for determination of phenolic compounds in milk products and wastewater.

    PubMed

    Sagiroglu, Ayten; Paluzar, Hatice; Ozcan, Hakki Mevlut; Okten, Suzan; Sen, Burhan

    2011-01-01

    Different branches of industry need to use phenolic compounds (PCs) in their production, so determination of PCs sensitively, accurately, rapidly, and economically is very important. For the sensitive determination of PCs, some biosensors based on pure polyphenol oxidase, plant tissue and microorganisms were developed before. But there has been no study to develop a microbial phenolic compounds biosensor based on Lactobacillus species, which contain polyphenol oxidase enzyme. In this study, we used different forms of Lactobacillus species as enzyme sources of biosensor and compared biosensor performances of these forms for determination of PCs. For this purpose, we used lyophilized Lactobacillus cells (containing L. bulgaricus, L. acidophilus, Streptococcus thermophilus), pure L. acidophilus, pure L. bulgaricus, and L. acidophilus- and L. bulgaricus adapted to catechol in Lactobacilli MRS Broth. The most suitable form was determined and optimization studies of the biosensor were carried out by using this form. For preparing the bioactive layer of the biosensor, the Lactobacillus cells were immobilized in gelatin by using glutaraldehyde. In the study, we used catechol as a substrate. Phenolic compound determination is based on the assay of the differences on the respiration activity of the cells on the oxygen meter in the absence and the presence of catechol. The microbial biosensor response depends directly on catechol concentration between 0.5 and 5.0 mM with 18 min response time. In the optimization studies of the microbial biosensor the most suitable microorganism amount was found to be 10 mg, and also phosphate buffer (pH 8.0; 50 mM) and 37.5 °C were obtained as the optimum working conditions. In the characterization studies of the microbial biosensor some parameters such as substrate specificity on the biosensor response and operational and storage stability were examine. Furthermore, the determination of PC levels in synthetic wastewater, industrial

  18. Influence of osmotic stress on the profile and gene expression of surface layer proteins in Lactobacillus acidophilus ATCC 4356.

    PubMed

    Palomino, María Mercedes; Waehner, Pablo M; Fina Martin, Joaquina; Ojeda, Paula; Malone, Lucía; Sánchez Rivas, Carmen; Prado Acosta, Mariano; Allievi, Mariana C; Ruzal, Sandra M

    2016-10-01

    In this work, we studied the role of surface layer (S-layer) proteins in the adaptation of Lactobacillus acidophilus ATCC 4356 to the osmotic stress generated by high salt. The amounts of the predominant and the auxiliary S-layer proteins SlpA and SlpX were strongly influenced by the growth phase and high-salt conditions (0.6 M NaCl). Changes in gene expression were also observed as the mRNAs of the slpA and slpX genes increased related to the growth phase and presence of high salt. A growth stage-dependent modification on the S-layer protein profile in response to NaCl was observed: while in control conditions, the auxiliary SlpX protein represented less than 10 % of the total S-layer protein, in high-salt conditions, it increased to almost 40 % in the stationary phase. The increase in S-layer protein synthesis in the stress condition could be a consequence of or a way to counteract the fragility of the cell wall, since a decrease in the cell wall thickness and envelope components (peptidoglycan layer and lipoteichoic acid content) was observed in L. acidophilus when compared to a non-S-layer-producing species such as Lactobacillus casei. Also, the stationary phase and growth in high-salt medium resulted in increased release of S-layer proteins to the supernatant medium. Overall, these findings suggest that pre-growth in high-salt conditions would result in an advantage for the probiotic nature of L. acidophilus ATCC 4356 as the increased amount and release of the S-layer might be appropriate for its antimicrobial capacity.

  19. Rennet paste from lambs fed a milk substitute supplemented with Lactobacillus acidophilus: effects on lipolysis in ovine cheese.

    PubMed

    Santillo, A; Quinto, M; Dentico, M; Muscio, A; Sevi, A; Albenzio, M

    2007-07-01

    The present work was undertaken to evaluate the effects of Lactobacillus acidophilus supplementation of a milk substitute on the features of lamb rennet paste used for cheese making. Lipolysis in cheese manufactured with rennet paste from lambs receiving supplemented milk was also evaluated. Lambs were subjected to 3 different feeding regimens (mother suckling, MS; artificial rearing, AR; and artificial rearing with 7 log10 cfu/mL of Lb. acidophilus supplementation of the milk substitute, ARLb) and slaughtered at 20 and 40 d of age for each feeding treatment. Abomasa of the lambs were processed to rennet paste. Microbial loads, enzymatic activities (chymosin, pepsin, and lipases), and renneting characteristics of the lamb rennet paste were determined. Free fatty acids and conjugated linoleic acids were detected in cheese at 60 d of ripening. Addition of 7 log10 cfu/mL of Lb. acidophilus to the milk substitute was carried out successfully. Total recovery of viable cells was recorded in milk supplied daily to the lambs in the ARLb group. The ARLb rennet had greater amounts of lactobacilli than did the MS or AR rennet, irrespective of the slaughter age of the lambs, and the ARLb rennet had higher concentrations of lactococci when lambs were slaughtered at 40 d of age. Chymosin and lipase activities were also higher in ARLb rennet than in MS or AR rennet from lambs slaughtered at an older age. Milk supplementation of ARLb lambs resulted in improved coagulating ability of the rennet and enhanced cheese lipolysis after 60 d of ripening. A reduction of all free fatty acids was observed in all cheeses when passing from 20 to 40 d of slaughter of the lambs. Conjugated linoleic acids were more abundant in ARLb cheeses at both 20 and 40 d. Therefore, supplementation of the milk substitute with Lb. acidophilus improved the enzymatic features of rennet and the healthful and nutritional characteristics of it the ovine cheese. Moreover, the addition of lactobacilli to the milk

  20. Identification and purification of a protein that induces production of the Lactobacillus acidophilus bacteriocin lactacin B.

    PubMed Central

    Barefoot, S F; Chen, Y R; Hughes, T A; Bodine, A B; Shearer, M Y; Hughes, M D

    1994-01-01

    Lactacin B is a heat-stable bacteriocin produced by Lactobacillus acidophilus N2 that is active against closely related lactobacilli, including Lactobacillus delbrueckii subsp. lactis (formerly Lactobacillus leichmannii) ATCC 4797. Pure producer cultures propagated in MRS broth (initial pH 6.5) contain no lactacin B; it is detected only in cultures maintained at pH 5.0 to 6.0 and produced optimally at pH 6.0 S. F. Barefoot and T. R. Klaenhammer, Antimicrob. Agents Chemother. 26:328-334, 1984). Associative growth of producer and indicator, L. delbrueckii subsp. lactis ATCC 4797, resulted in production of an inhibitor identical to lactacin B. Associative growth increased lactacin B production from nondetectable levels (< 100 activity units [AU]/ml) to between 3,200 and 6,400 AU/ml in MRS broth (initial pH 6.5) and resulted in early but equal production of lactacin B (approximately 25,600 AU/ml) in broth maintained at pH 6.0. Indicator cells, but not spent culture filtrates, induced lactacin B production. Indicator cells disrupted by a French pressure cell yielded cell-free filtrates containing inducing activity. Chromatofocusing and gel filtration high-performance liquid chromatography of cell-free filtrates yielded a protein with a pI of 4.1 and a molecular size of approximately 58 kDa that induced lactacin B production. Analytical isoelectric focusing yielded a single protein band. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis gels contained a 28-kDa protein suggesting a two-subunit structure. Protein sequencing identified an N-terminal serine and 18 additional amino acids. To our knowledge, there are not previous descriptions of proteins that induce bacteriocin production in lactic acid bacteria. Images PMID:7986029

  1. Solution Structure of Acidocin B, a Circular Bacteriocin Produced by Lactobacillus acidophilus M46

    PubMed Central

    Acedo, Jeella Z.; van Belkum, Marco J.; Lohans, Christopher T.; McKay, Ryan T.; Miskolzie, Mark

    2015-01-01

    Acidocin B, a bacteriocin produced by Lactobacillus acidophilus M46, was originally reported to be a linear peptide composed of 59 amino acid residues. However, its high sequence similarity to gassericin A, a circular bacteriocin from Lactobacillus gasseri LA39, suggested that acidocin B might be circular as well. Acidocin B was purified from culture supernatant by a series of hydrophobic interaction chromatographic steps. Its circular nature was ascertained by matrix-assisted laser desorption ionization–time of flight (MALDI-TOF) mass spectrometry and tandem mass spectrometry (MS/MS) sequencing. The peptide sequence was found to consist of 58 amino acids with a molecular mass of 5,621.5 Da. The sequence of the acidocin B biosynthetic gene cluster was also determined and showed high nucleotide sequence similarity to that of gassericin A. The nuclear magnetic resonance (NMR) solution structure of acidocin B in sodium dodecyl sulfate micelles was elucidated, revealing that it is composed of four α-helices of similar length that are folded to form a compact, globular bundle with a central pore. This is a three-dimensional structure for a member of subgroup II circular bacteriocins, which are classified based on their isoelectric points of ∼7 or lower. Comparison of acidocin B with carnocyclin A, a subgroup I circular bacteriocin with four α-helices and a pI of 10, revealed differences in the overall folding. The observed variations could be attributed to inherent diversity in their physical properties, which also required the use of different solvent systems for three-dimensional structural elucidation. PMID:25681186

  2. Solution structure of acidocin B, a circular bacteriocin produced by Lactobacillus acidophilus M46.

    PubMed

    Acedo, Jeella Z; van Belkum, Marco J; Lohans, Christopher T; McKay, Ryan T; Miskolzie, Mark; Vederas, John C

    2015-04-01

    Acidocin B, a bacteriocin produced by Lactobacillus acidophilus M46, was originally reported to be a linear peptide composed of 59 amino acid residues. However, its high sequence similarity to gassericin A, a circular bacteriocin from Lactobacillus gasseri LA39, suggested that acidocin B might be circular as well. Acidocin B was purified from culture supernatant by a series of hydrophobic interaction chromatographic steps. Its circular nature was ascertained by matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry and tandem mass spectrometry (MS/MS) sequencing. The peptide sequence was found to consist of 58 amino acids with a molecular mass of 5,621.5 Da. The sequence of the acidocin B biosynthetic gene cluster was also determined and showed high nucleotide sequence similarity to that of gassericin A. The nuclear magnetic resonance (NMR) solution structure of acidocin B in sodium dodecyl sulfate micelles was elucidated, revealing that it is composed of four α-helices of similar length that are folded to form a compact, globular bundle with a central pore. This is a three-dimensional structure for a member of subgroup II circular bacteriocins, which are classified based on their isoelectric points of ∼7 or lower. Comparison of acidocin B with carnocyclin A, a subgroup I circular bacteriocin with four α-helices and a pI of 10, revealed differences in the overall folding. The observed variations could be attributed to inherent diversity in their physical properties, which also required the use of different solvent systems for three-dimensional structural elucidation.

  3. Stability of microencapsulated B. lactis (BI 01) and L. acidophilus (LAC 4) by complex coacervation followed by spray drying.

    PubMed

    Oliveira, A C; Moretti, T S; Boschini, C; Baliero, J C C; Freitas, O; Favaro-Trindade, C S

    2007-11-01

    Microcapsules containing Bifidobacterium lactis (BI 01) and Lactobacillus acidophilus (LAC 4) were produced by complex coacervation using a casein/pectin complex as the wall material, followed by spray drying. The aim of this study was to evaluate the resistance of these microorganisms when submitted to the spray drying process, a shelf-life of 120 days at 7-37 degrees C and the in vitro tolerance after being submitted to acid pH (pH 1.0 and 3.0) solutions besides morphology of microcapsules. Microencapsulated microorganisms were shown to be more resistant to acid conditions than free ones. Microencapsulated L. acidophilus maintained its viability for a longer storage period at both temperatures. The microcapsules presented a spherical shape with no fissures. The process used and the wall material were efficient in protecting the microorganisms under study against the spray drying process and simulated gastric juice; however, microencapsulated B. lactis lost its viability before the end of the storage time.

  4. Evaluation of Lactobacillus rhamnosus GG and Lactobacillus acidophilus NCFM encapsulated using a novel impinging aerosol method in fruit food products.

    PubMed

    Sohail, Asma; Turner, Mark S; Prabawati, Elisabeth Kartika; Coombes, Allan G A; Bhandari, Bhesh

    2012-07-02

    This study investigated the effect of microencapsulation on the survival of Lactobacillus rhamnosus GG and Lactobacillus acidophilus NCFM and their acidification in orange juice at 25°C for nine days and at 4°C over thirty five days of storage. Alginate micro beads (10-40 μm) containing the probiotics were produced by a novel dual aerosol method of alginate and CaCl(2) cross linking solution. Unencapsulated L. rhamnosus GG was found to have excellent survivability in orange juice at both temperatures. However unencapsulated L. acidophilus NCFM showed significant reduction in viability. Encapsulation of these two bacteria did not significantly enhance survivability but did reduce acidification at 25°C and 4°C. In agreement with this, encapsulation of L. rhamnosus GG also reduced acidification in pear and peach fruit-based foods at 25°C, however at 4°C difference in pH was insignificant between free and encapsulated cells. In conclusion, L. rhamnosus GG showed excellent survival in orange juice and microencapsulation has potential in reducing acidification and possible negative sensory effects of probiotics in orange juice and other fruit-based products.

  5. Enhanced survival of probiotic Lactobacillus acidophilus by encapsulation with nanostructured polyelectrolyte layers through layer-by-layer approach.

    PubMed

    Priya, Angel J; Vijayalakshmi, S P; Raichur, Ashok M

    2011-11-09

    The encapsulation of probiotic Lactobacillus acidophilus through layer-by-layer self-assembly of polyelectrolytes (PE) chitosan (CHI) and carboxymethyl cellulose (CMC) has been investigated to enhance its survival in adverse conditions encountered in the GI tract. The survival of encapsulated cells in simulated gastric (SGF) and intestinal fluids (SIF) is significant when compared to nonencapsulated cells. On sequential exposure to SGF and SIF for 120 min, almost complete death of free cells is observed. However, for cells coated with three nanolayers of PEs (CHI/CMC/CHI), about 33 log % of the cells (6 log cfu/500 mg) survived under the same conditions. The enhanced survival rate of encapsulated L. acidophilus can be attributed to the impermeability of polyelectrolyte nanolayers to large enzyme molecules like pepsin and pancreatin that cause proteolysis and to the stability of the polyelectrolyte nanolayers in gastric and intestinal pH. The PE coating also serves to reduce viability losses during freezing and freeze-drying. About 73 and 92 log % of uncoated and coated cells survived after freeze-drying, and the losses occurring between freezing and freeze-drying were found to be lower for the coated cells.

  6. Production of Succinic Acid from Citric Acid and Related Acids by Lactobacillus Strains

    PubMed Central

    Kaneuchi, Choji; Seki, Masako; Komagata, Kazuo

    1988-01-01

    A number of Lactobacillus strains produced succinic acid in de Man-Rogosa-Sharpe broth to various extents. Among 86 fresh isolates from fermented cane molasses in Thailand, 30 strains (35%) produced succinic acid; namely, 23 of 39 Lactobacillus reuteri strains, 6 of 18 L. cellobiosus strains, and 1 of 6 unidentified strains. All of 10 L. casei subsp. casei strains, 5 L. casei subsp. rhamnosus strains, 6 L. mali strains, and 2 L. buchneri strains did not produce succinic acid. Among 58 known strains including 48 type strains of different Lactobacillus species, the strains of L. acidophilus, L. crispatus, L. jensenii, and L. parvus produced succinic acid to the same extent as the most active fresh isolates, and those of L. alimentarius, L. collinoides, L. farciminis, L. fructivorans (1 of 2 strains tested), L. malefermentans, and L. reuteri were also positive, to lesser extents. Diammonium citrate in de Man-Rogosa-Sharpe broth was determined as a precursor of the succinic acid produced. Production rates were about 70% on a molar basis with two fresh strains tested. Succinic acid was also produced from fumaric and malic acids but not from dl-isocitric, α-ketoglutaric, and pyruvic acids. The present study is considered to provide the first evidence on the production of succinic acid, an important flavoring substance in dairy products and fermented beverages, from citrate by lactobacilli. PMID:16347795

  7. Microencapsulation of L. acidophilus (La-05) and B. lactis (Bb-12) and evaluation of their survival at the pH values of the stomach and in bile.

    PubMed

    Fávaro-Trindade, C S; Grosso, C R F

    2002-01-01

    Microcapsules were prepared using the probiotic microorganisms Lactobacillus acidophilus (La-05) and Bifidobacterium lactis (Bb-12) and the spray drying technique and cellulose acetate phthalate as the wall material. This study evaluated the resistance of these microorganisms to drying at three temperatures and also the in vitro tolerance of the free and microencapsulated form to pH values and bile concentrations similar to those found in the human stomach and intestine. With an air entry temperature of 130 degrees C and exit temperature of 75 degrees C, the number of viable cells of B. lactis was practically unaltered, whereas the population of L. acidophilus was reduced by two logarithmic cycles. B. lactis was more resistant to the drying process than L. acidophilus under all conditions tested. The morphology of the microcapsules was determined by scanning electron microscopy and the microcapsules presented a rounded external surface containing concavities, a continuous wall with no apparent porosity, average size of 22 microm, moisture content varying from 5.3 to 3.2% and water activity between 0.230 and 0.204. After inoculation into HCl solutions with pH values adjusted to 1 and 2, incubated anaerobically at 37 degrees C, and plated after 0, 1 and 2 h of incubation, microcapsules were effective in protecting the microorganisms, while the populations of both free microorganisms were eliminated after only 1 h at the acidic conditions. Microencapsulated B. lactis and L. acidophilus, both free and microencapsulated, were also resistant after 12h to bile solutions.

  8. A mild pulsed electric field condition that improves acid tolerance, growth, and protease activity of Lactobacillus acidophilus LA-K and Lactobacillus delbrueckii subspecies bulgaricus LB-12.

    PubMed

    Najim, N; Aryana, Kayanush J

    2013-06-01

    Pulsed electric field (PEF) processing involves the application of pulses of voltage for less than 1 s to fluid products placed between 2 electrodes. The effect of mild PEF on beneficial characteristics of probiotic bacteria Lactobacillus acidophilus and Lactobacillus delbrueckii ssp. bulgaricus is not clearly understood. The objective of this study was to determine the influence of mild PEF conditions on acid tolerance, growth, and protease activity of Lb. acidophilus LA-K and Lactobacillus delbrueckii ssp. bulgaricus LB-12. A pilot plant PEF system (OSU-4M; The Ohio State University, Columbus) was used. The PEF treatments were positive square unipolar pulse width of 3 µs, pulse period of 0.5s, electric field strength of 1 kV/cm, delay time of 20 µs, flow rate of 60 mL/min, and 40.5°C PEF treatment temperature. Both Lb. acidophilus LA-K and Lb. bulgaricus LB-12 subjected to mild PEF conditions were acid tolerant until the end of the 120 min of incubation, unlike the Lb. bulgaricus control, which was not acid tolerant after 30 min. The mild PEF-treated Lb. acidophilus LA-K and Lb. bulgaricus LB-12 reached the logarithmic phase of growth an hour earlier than the control. Mild PEF conditions studied significantly improved acid tolerance, exponential growth, and protease activity of both Lb. acidophilus LA-K and Lb. bulgaricus LB-12 compared with the control. The mild PEF conditions studied can be recommended for pretreating cultures to enhance these desirable attributes.

  9. Dietary Lactobacillus acidophilus modulated skin mucus protein profile, immune and appetite genes expression in gold fish (Carassius auratus gibelio).

    PubMed

    Hosseini, Marjan; Kolangi Miandare, Hamed; Hoseinifar, Seyed Hossein; Yarahmadi, Peyman

    2016-12-01

    The objective of the present study was to investigate the effect of dietary Lactobacillus acidophilus on skin mucus protein pattern, immune and appetite related genes expression as well as growth performance in gold fish (Carassius auratus gibelio). Three hundred healthy gold fish (2.5 ± 0.05) juveniles were randomly distributed in 12 glass aquariums (400-L; 25 fish per aquaria) and fed experimental diets contain different levels of L. acidophilus (0, 1.5 × 10(8), 3 × 10(8) and 6 × 10(8)) for 8 weeks. SDS-PAGE analysis of skin mucus protein profile at the end of the feeding trial revealed differences in protein profile of probiotic fed fish and control group; even three new bands were observed in L. acidophilus treated groups. Furthermore, fish fed 6 × 10(8) CFU g(-1) supplemented diet showed up-regulation of both TNF-1α and TNF-2α gene expression (P < 0.05). Evaluation of appetite related gene expression showed down-regulation of ghrelin in probiotic fed fish compared those of control treatment (P < 0.05). However, administration of different levels of L. acidophilus had no significant effects on growth performance (P > 0.05). These results demonstrated that while no beneficial effects on growth performance, dietary L. acidophilus affects immune and appetite related genes expression as well as skin mucus protein profile.

  10. Growth and Survival of Some Probiotic Strains in Simulated Ice Cream Conditions

    NASA Astrophysics Data System (ADS)

    Homayouni, A.; Ehsani, M. R.; Azizi, A.; Razavi, S. H.; Yarmand, M. S.

    A Completely Randomized Design (CRD) experiment was applied in triplicates to evaluate the survival of four probiotic strains in simulated ice cream conditions. The growth and survival rate of these probiotic strains (Lactobacillus acidophilus, Lactobacillus casei, Bifidobacterium bifidum and Bifidobacterium longum) in varying amount of sucrose (10, 15, 20 and 25%), oxygen scavenging components (0.05% L-cysteine and 0.05% L-ascorbate) and temperatures (4 and -20°C) during different periods of time (1, 2 and 3 months) were evaluated in MRS-broth medium. Optical density at 580 nm was used to measure growth. Lactobacilli strains proved to be highly resistant in comparison with Biffidobacteria strains. The viable cell number of Lactobacillus casei in different sucrose concentrations, different oxidoreduction potentials and refrigeration temperature was 1x1010, 2x108 and 5x107 cfu mL-1, respectively. Growth and survival rate of Lactobacillus casei showed to be the highest.

  11. A Decade of Experience in Primary Prevention of Clostridium difficile Infection at a Community Hospital Using the Probiotic Combination Lactobacillus acidophilus CL1285, Lactobacillus casei LBC80R, and Lactobacillus rhamnosus CLR2 (Bio-K+).

    PubMed

    Maziade, Pierre-Jean; Pereira, Pascale; Goldstein, Ellie J C

    2015-05-15

    In August 2003, the 284-bed community hospital Pierre-Le Gardeur (PLGH) in Quebec experienced a major outbreak associated with the Clostridium difficile NAP1/027/BI strain. Augmented standard preventive measures (SPMs) were not able to control this outbreak. It was decided in February 2004 to give to every adult inpatient on antibiotics, without any exclusion, a probiotic (Bio-K+: Lactobacillus acidophilus CL1285, Lactobacillus casei LBC80R, and Lactobacillus rhamnosus CLR2) within 12 hours of the antibiotic prescription. Augmented SPMs were continued. The use of the probiotic in addition to SPMs was associated with a marked reduction of C. difficile infection (CDI). During the 10 years of observation, 44 835 inpatients received Bio-K+, and the CDI rate at PLGH declined from 18.0 cases per 10,000 patient-days and remained at low mean levels of 2.3 cases per 10,000 patient-days. Additionally, 10-year data collected by the Ministry of Health in Quebec comparing the CDI rate between Quebec hospitals showed that CDI rates at PLGH were consistently and continuously lower compared with those at similar hospitals. Blood cultures were monitored at PLGH for Lactobacillus bacteremia through the 10 years' experience, and no Lactobacillus bacteremias were detected. Despite the limitation of an observational study, we concluded that the probiotic Bio-K+ was safe and effective in decreasing our primary CDI rate.

  12. Effect of tween series on growth and Cis-9, trans-11 conjugated linoleic acid production of Lactobacillus acidophilus F0221 in the presence of bile salts.

    PubMed

    Li, Jing-Yan; Zhang, Lan-Wei; Du, Ming; Han, Xue; Yi, Hua-Xi; Guo, Chun-Feng; Zhang, Ying-Chun; Luo, Xue; Zhang, Yan-He; Shan, Yu-Juan; Hou, Ai-Ju

    2011-01-01

    Cis-9, trans-11 conjugated linoleic acid (c9, t11 CLA) producing bacteria have attracted much attention as novel probiotics which have shown beneficial effects on host health. However, bile salts are able to inhibit bacterial growth and c9, t11 CLA production. For recovering growth and c9, t11 CLA production of Lactobacillus acidophilus F0221 in the presence of bile salts, Tween series (Tween 20, Tween 40, Tween 60 and Tween 80) were added in growth culture containing 0.3% oxgall. Results showed that the viable counts were significantly (P < 0.05) recovered to 8.58-8.75 log CFU/mL in the presence of all Tween treatments. However, recovery of c9, t11 CLA production was only demonstrated in the presence of Tween 80 (72.89 μg/mL). Stepwise increasing oxgall in a concentrations range from 0.1% to 0.9% according to human intestinal physiological environments, Tween 80 still showed significant (P < 0.05) recovery ability on growth (8.91-8.04 log CFU/mL) and c9, t11 CLA (69.22-34.27 μg/mL) production. The effect of Tween 80 on growth and production was also investigated in the presence of different types of bile salts (sodium salts of cholic acid (CA), deoxycholic acid (DCA), chendeoxycholic acid (CDCA), glycocholic acid (GCA) and taurocholic acid (TCA)). Results showed that Tween 80 could significantly (P < 0.05) recover c9, t11 CLA production in the presence of all types of bile salts, but the Tween 80 could only significantly (P < 0.05) recover viable counts of the strain in the presence of CA, DCA and CDCA. This recovery ability could be attributed to the protection of leakage of intracellular material. Additionally, although bile salts inhibited growth and c9, t11 CLA production by the growing cell, it promoted the c9, t11 CLA production by the resting cell.

  13. Advancing the use of Lactobacillus acidophilus surface layer protein A for the treatment of intestinal disorders in humans

    PubMed Central

    Sahay, Bikash; Ge, Yong; Colliou, Natacha; Zadeh, Mojgan; Weiner, Chelsea; Mila, Ashley; Owen, Jennifer L; Mohamadzadeh, Mansour

    2015-01-01

    Intestinal immunity is subject to complex and fine-tuned regulation dictated by interactions of the resident microbial community and their gene products with host innate cells. Deterioration of this delicate process may result in devastating autoinflammatory diseases, including inflammatory bowel disease (IBD), which primarily comprises Crohn's disease (CD) and ulcerative colitis (UC). Efficacious interventions to regulate proinflammatory signals, which play critical roles in IBD, require further scientific investigation. We recently demonstrated that rebalancing intestinal immunity via the surface layer protein A (SlpA) from Lactobacillus acidophilus NCFM potentially represents a feasible therapeutic approach to restore intestinal homeostasis. To expand on these findings, we established a new method of purifying bacterial SlpA, a new SlpA-specific monoclonal antibody, and found no SlpA-associated toxicity in mice. Thus, these data may assist in our efforts to determine the immune regulatory efficacy of SlpA in humans. PMID:26647142

  14. Peripheral Light-Harvesting LH2 Complex Can Be Assembled in Cells of Nonsulfur Purple Bacterium Rhodoblastus acidophilus without Carotenoids.

    PubMed

    Bol'shakov, M A; Ashikhmin, A A; Makhneva, Z K; Moskalenko, A A

    2015-09-01

    The effect of carotenoids on the assembly of LH2 complex in cells of the purple nonsulfur bacterium Rhodoblastus acidophilus was investigated. For this purpose, the bacterial culture was cultivated with an inhibitor of carotenoid biosynthesis - 71 µM diphenylamine (DPA). The inhibitor decreased the level of biosynthesis of the colored carotenoids in membranes by ~58%. It was found that a large amount of phytoene was accumulated in them. This carotenoid precursor was bound nonspecifically to LH2 complex and did not stabilize its structure. Thermostability testing of the isolated LH2 complex together with analysis of carotenoid composition revealed that the population of this complex was heterogeneous with respect to carotenoid composition. One fraction of the LH2 complex with carotenoid content around 90% remains stable and was not destroyed under heating for 15 min at 50°C. The other fraction of LH2 complex containing on average less than one molecule of carotenoid per complex was destroyed under heating, forming a zone of free pigments (and polypeptides). The data suggest that a certain part of the LH2 complexes is assembled without carotenoids in cells of the nonsulfur bacterium Rbl. acidophilus grown with DPA. These data contradict the fact that the LH2 complex from nonsulfur bacteria cannot be assembled without carotenoids, but on the other hand, they are in good agreement with the results demonstrated in our earlier studies of the sulfur bacteria Allochromatium minutissimum and Ectothiorhodospira haloalkaliphila. Carotenoidless LH2 complex was obtained from these bacteria with the use of DPA (Moskalenko, A. A., and Makhneva, Z. K. (2012) J. Photochem. Photobiol., 108, 1-7; Ashikhmin, A., et al. (2014) Photosynth. Res., 119, 291-303).

  15. Enzymology and Structure of the GH13_31 Glucan 1,6-α-Glucosidase That Confers Isomaltooligosaccharide Utilization in the Probiotic Lactobacillus acidophilus NCFM

    PubMed Central

    Møller, Marie S.; Fredslund, Folmer; Majumder, Avishek; Nakai, Hiroyuki; Poulsen, Jens-Christian N.; Lo Leggio, Leila; Svensson, Birte

    2012-01-01

    Isomaltooligosaccharides (IMO) have been suggested as promising prebiotics that stimulate the growth of probiotic bacteria. Genomes of probiotic lactobacilli from the acidophilus group, as represented by Lactobacillus acidophilus NCFM, encode α-1,6 glucosidases of the family GH13_31 (glycoside hydrolase family 13 subfamily 31) that confer degradation of IMO. These genes reside frequently within maltooligosaccharide utilization operons, which include an ATP-binding cassette transporter and α-glucan active enzymes, e.g., maltogenic amylases and maltose phosphorylases, and they also occur separated from any carbohydrate transport or catabolism genes on the genomes of some acidophilus complex members, as in L. acidophilus NCFM. Besides the isolated locus encoding a GH13_31 enzyme, the ABC transporter and another GH13 in the maltooligosaccharide operon were induced in response to IMO or maltotetraose, as determined by reverse transcription-PCR (RT-PCR) transcriptional analysis, suggesting coregulation of α-1,6- and α-1,4-glucooligosaccharide utilization loci in L. acidophilus NCFM. The L. acidophilus NCFM GH13_31 (LaGH13_31) was produced recombinantly and shown to be a glucan 1,6-α-glucosidase active on IMO and dextran and product-inhibited by glucose. The catalytic efficiency of LaGH13_31 on dextran and the dextran/panose (trisaccharide) efficiency ratio were the highest reported for this class of enzymes, suggesting higher affinity at distal substrate binding sites. The crystal structure of LaGH13_31 was determined to a resolution of 2.05 Å and revealed additional substrate contacts at the +2 subsite in LaGH13_31 compared to the GH13_31 from Streptococcus mutans (SmGH13_31), providing a possible structural rationale to the relatively high affinity for dextran. A comprehensive phylogenetic and activity motif analysis mapped IMO utilization enzymes from gut microbiota to rationalize preferential utilization of IMO by gut residents. PMID:22685275

  16. Natural Strain

    NASA Technical Reports Server (NTRS)

    Freed, Alan D.

    1995-01-01

    The purpose of this paper is to present a consistent and thorough development of the strain and strain-rate measures affiliated with Hencky. Natural measures for strain and strain-rate, as I refer to them, are first expressed in terms of of the fundamental body-metric tensors of Lodge. These strain and strain-rate measures are mixed tensor fields. They are mapped from the body to space in both the Eulerian and Lagrangian configurations, and then transformed from general to Cartesian fields. There they are compared with the various strain and strain-rate measures found in the literature. A simple Cartesian description for Hencky strain-rate in the Lagrangian state is obtained.

  17. Microencapsulation of Lactobacillus acidophilus NCIMB 701748 in matrices containing soluble fibre by spray drying: Technological characterization, storage stability and survival after in vitro digestion☆

    PubMed Central

    Yonekura, Lina; Sun, Han; Soukoulis, Christos; Fisk, Ian

    2014-01-01

    We evaluated sodium alginate, chitosan and hydroxypropyl methylcellulose (HPMC) as co-encapsulants for spray dried Lactobacillus acidophilus NCIMB 701748 by assessing their impact on cell viability and physicochemical properties of the dried powders, viability over 35 days of storage at 25 °C and survival after simulated digestion. Fibres were added to a control carrier medium containing whey protein concentrate, d-glucose and maltodextrin. Sodium alginate and HPMC did not affect cell viability but chitosan reduced viable counts in spray dried powders, as compared to the control. Although chitosan caused large losses of viability during spray-drying, these losses were counteracted by the excellent storage stability compared to control, sodium alginate and HPMC, and the overall effect became positive after the 35-day storage. Chitosan also improved survival rates in simulated GI conditions, however no single fibre could improve L. acidophilus NCIMB 701748 viability in all steps from production through storage and digestion. PMID:24748900

  18. The formation of germtubes by Candida albicans, when grown with Staphylococcus pyogene, Escherichia coli, Klebsiella pneumoniae, Lactobacilius acidophilus and Proteus vulgaris.

    PubMed

    Purohit, B C; Joshi, K R; Ramdeo, I N; Bharadwaj, T P

    1977-12-31

    The formation of germtubes by twelve clinical isolates of C. albicans was studied in human serum containing per millilitre 10(3) to 10(9) organisms as: Staphylococcus pyegene, Escherichia coli, Klebsiella pneumoniae, Lactobacillus acidophilus and Proteus vulgaris. All the five bacteria inhibited formation of germtubes by C. albicans at all concentrations and the percent germtube formed diminished with increasing concentration of the bacteria. Lactobacillus acidophilus inhibited the formation of germtubes maximally followed by Staphylococcus pyogene, Escherichia coli and Klebsiella pneumoniae. Proteus vulgaris in the concentrations of 10(3) to 10(7) bacteria per millilitre produced only insignificant inhibition of formation of germtubes by C. albicans. Since germtubes of C. albicans are invasive, it is suggested that inhibition of "blastospore-germtube transformation" may be significantly responsible for prevention of infection by C. albicans by coexisting bacterial flora.

  19. Microencapsulation of Lactobacillus acidophilus NCIMB 701748 in matrices containing soluble fibre by spray drying: Technological characterization, storage stability and survival after in vitro digestion.

    PubMed

    Yonekura, Lina; Sun, Han; Soukoulis, Christos; Fisk, Ian

    2014-01-01

    We evaluated sodium alginate, chitosan and hydroxypropyl methylcellulose (HPMC) as co-encapsulants for spray dried Lactobacillus acidophilus NCIMB 701748 by assessing their impact on cell viability and physicochemical properties of the dried powders, viability over 35 days of storage at 25 °C and survival after simulated digestion. Fibres were added to a control carrier medium containing whey protein concentrate, d-glucose and maltodextrin. Sodium alginate and HPMC did not affect cell viability but chitosan reduced viable counts in spray dried powders, as compared to the control. Although chitosan caused large losses of viability during spray-drying, these losses were counteracted by the excellent storage stability compared to control, sodium alginate and HPMC, and the overall effect became positive after the 35-day storage. Chitosan also improved survival rates in simulated GI conditions, however no single fibre could improve L. acidophilus NCIMB 701748 viability in all steps from production through storage and digestion.

  20. Probiotics Lactobacillus rhamnosus GG, Lactobacillus acidophilus suppresses DMH-induced procarcinogenic fecal enzymes and preneoplastic aberrant crypt foci in early colon carcinogenesis in Sprague Dawley rats.

    PubMed

    Verma, Angela; Shukla, Geeta

    2013-01-01

    Diet makes an important contribution to colorectal cancer (CRC) risk implying risks for CRC are potentially reducible. Therefore, the probiotics have been suggested as the prophylactic measure in colon cancer. In this study, different probiotics were used to compare their protective potential against 1,2 dimethylhydrazine dihydrochloride (DMH)-induced chemical colon carcinogenesis in Sprague Dawley rats. Animals belonging to different probiotic groups were fed orally with 1 × 10(9) lactobacilli daily for 1 week, and then a weekly injection of DMH was given intraperitoneally for 6 wks with daily administration of probiotic. Lactobacillus GG and L.acidophilus + DMH-treated animals had maximum percent reduction in ACF counts. A significant decrease (P < 0.05) in fecal nitroreductase activity was observed in L.casei + DMH and L.plantarum + DMH-treated rats whereas β-glucuronidase activity decreased in L.GG + DMH and L.acidophilus + DMH-treated rats. Animals treated with Bifidobacterium bifidum + DMH had significant decreased β-glucosidase activity. However, not much difference was observed in the colon morphology of animals belonging to various probiotic + DMH-treated rats compared with DMH-treated alone. The results indicated that probiotics, L.GG, and L.acidophilus can be used as the better prophylactic agents for experimental colon carcinogenesis.

  1. How does the supernatant of Lactobacillus acidophilus affect the proliferation and differentiation activities of rat bone marrow-derived stromal cells?

    PubMed

    Samadikuchaksaraei, A; Gholipourmalekabadi, M; Saberian, M; Abdollahpour Alitappeh, M; Shahidi Delshad, E

    2016-08-31

    Low proliferation rate and unwanted differentiation of bone marrow-derived stromal cells (rBMSCs) during the frequent passages have limited the use of such cells in clinical cell therapy. Recently, the researchers have focused on the effects of the components produced by some bacteria on proliferation of the stem cells. In this study, we discussed the possible effects of the Lactobacillus acidophilus supernatant on proliferation and differentiation of the rBMSCs. For this aim, the cells were isolated from rat bone marrow, characterized by culturing on tissue specific differentiation media and stained. The cells (passage two) were treated with different concentrations of the L. acidophilus supernatant (0, 0.1, 0.3, 0.9, 3, 9 and 30 &mgr;l/ml) for 14 days. The proliferation and differentiation capacity of the cells were then determined by 3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide (MTT assay) and tissue specific staining. The results showed a positive effect of the supernatant on the cell proliferation in 3 and 9 &mgr;l/ml concentrations, while did not affect the differentiation capacity of the rBMSCs. The current study strongly suggests the L. acidophilus supernatant as an alternative material that could be added to the media with aim of improvement in the proliferation rate of the rBMSCs without affecting their differentiation capacity.

  2. Lactobacillus acidophilus La5 and Bifidobacterium lactis Bb12 cell surface hydrophobicity and survival of the cells under adverse environmental conditions.

    PubMed

    Shakirova, Laisana; Grube, Mara; Gavare, Marita; Auzina, Lilija; Zikmanis, Peteris

    2013-01-01

    Changes in the cell surface hydrophobicity (CSH) of probiotic bacteria Lactobacillus acidophilus La5 and Bifidobacterium lactis Bb12 and the survival of these cells were examined in response to varied cultivation conditions and adverse environmental conditions. An inverse linear relationship (P < 0.01) was detected between the CSH of intact L. acidophilus La5 and B. lactis Bb12 and survival of cells subjected to subsequent freezing/thawing, long-term storage or exposure to mineral and bile acids. The observed relationships were supported by significant correlations between the CSH and changes in composition of the cell envelopes (proteins, lipids and carbohydrates) of L. acidophilus La5 and B. lactis Bb12 examined using FT-IR spectroscopy and conventional biochemical analysis methods. The results also suggest that the estimates of hydrophobicity, being a generalized characteristic of cell surfaces, are important parameters to predict the ability of intact probiotic bacteria to endure extreme environments and therefore should be monitored during cultivation. A defined balance of cell components, which can be characterized by the reduced CSH values, apparently helps to ensure the resistance, improved viability and hence the overall probiotic properties of bacteria.

  3. Effects of salt concentration and pH on structural and functional properties of Lactobacillus acidophilus: FT-IR spectroscopic analysis.

    PubMed

    Gandhi, Akanksha; Shah, Nagendra P

    2014-03-03

    The effects of sodium chloride concentration and varying pH levels on the structural and functional properties of Lactobacillus acidophilus were investigated. Reconstituted skim milk was inoculated with Lb. acidophilus at varying salt concentrations (0, 1, 2, 5 and 10% NaCl) and pH levels (4.0, 5.0 and 6.0) and ACE-inhibitory activity and proteolytic activity were determined and the viable cell count was enumerated after 24h of fermentation at 37 °C. The degree of proteolysis exhibited an increase with higher salt concentration at pH 5.0 and 6.0. ACE-inhibitory activity was found to be the highest at pH 5.0 at all salt concentrations. Fourier transform infrared spectroscopy results demonstrated significant changes occurring beyond 2% NaCl particularly at low pH (4.0). The findings revealed that significant changes occurred in amide I and amide III regions when Lb. acidophilus was subjected to varying salt concentrations.

  4. Comparable effects of low-intensity electromagnetic irradiation at the frequency of 51.8 and 53 GHz and antibiotic ceftazidime on Lactobacillus acidophilus growth and survival.

    PubMed

    Soghomonyan, Diana; Trchounian, Armen

    2013-01-01

    The effects of low-intensity electromagnetic irradiation (EMI) with the frequencies of 51.8 and 53 GHz on Lactobacillus acidophilus growth and survival were revealed. These effects were compared with antibacterial effects of antibiotic ceftazidime. Decrease in bacterial growth rate by EMI was comparable with the inhibitory effect of ceftazidime (minimal inhibitory concentration-16 μM) and no enhanced action was observed with combined effects of EMI and the antibiotic. However, EMI-enhanced antibiotic inhibitory effect on bacterial survival. The kinetics of the bacterial suspension oxidation-reduction potential up to 24 h of the growth was changed by EMI and ceftazidime. The changes were more strongly expressed by combined effects of EMI and antibiotic especially up to 12 h. Moreover, EMI did not change overall energy (glucose)-dependent H(+) efflux across the membrane but it increased N,N'-dicyclohexylcarbodiimide (DCCD)-inhibited H(+) efflux. In contrast, this EMI in combination with ceftazidime decreased DCCD-sensitive H(+) efflux. Low-intensity EMI had inhibitory effect on L. acidophilus bacterial growth and survival. The effect on bacterial survival was more significant in the combination with ceftazidime. The H(+)-translocating F 0 F 1-ATPase, for which DCCD is specific inhibitor, might be a target for EMI and ceftazidime. The revealed bactericide effects on L. acidophilus can be applied in biotechnology, food producing and safety technology.

  5. Effect of yogurt containing polydextrose, Lactobacillus acidophilus NCFM and Bifidobacterium lactis HN019: a randomized, double-blind, controlled study in chronic constipation

    PubMed Central

    2014-01-01

    Background Constipation is a frequent complaint and the combination of a prebiotic and probiotics could have a potentially synergic effect on the intestinal transit. The present study therefore aims to investigate the combination of polydextrose (Litesse®), L. acidophilus NCFM® and B. lactis HN019 in a yogurt on intestinal transit in subjects who suffer from constipation. Methods Patients with constipation were randomly divided into two groups, Control Group (CG) and Treatment Group (TG), and had to eat 180 ml of unflavored yogurt every morning for 14 days. Those in the CG received only yogurt, while the TG received yogurt containing polydextrose, L. acidophilus NCFM® (ATCC 700396) and B. lactis HN019 (AGAL NM97/09513). Results Favourable clinical response was assessed since Agachan score had a significant reduction at the end of the study in both groups and tended to be better in the TG. The subjects in the treatment group also had a shorter transit time at the end of the intervention compared to the control group (p = 0.01). Conclusion The product containing yogurt with polydextrose, B. lactis HN019 and L. acidophilus NCFM® significantly shortened colonic transit time after two weeks in the TG compared to CG and may be an option for treatment of constipation. PMID:25056655

  6. Short communication: Viability of culture organisms in honey-enriched acidophilus-bifidus-thermophilus (ABT)-type fermented camel milk.

    PubMed

    Varga, L; Süle, J; Nagy, P

    2014-11-01

    The aim of this research was to monitor the survival during refrigerated storage of Lactobacillus acidophilus LA-5 (A), Bifidobacterium animalis ssp. lactis BB-12 (B), and Streptococcus thermophilus CHCC 742/2130 (T) in cultured dairy foods made from camel and, for comparison, cow milks supplemented with black locust (Robinia pseudoacacia L.) honey and fermented by an acidophilus-bifidus-thermophilus (ABT)-type culture. Two liters of dromedary camel milk and 2 L of cow milk were heated to 90 °C and held for 10 min, then cooled to 40 °C. One half of both types of milk was fortified with black locust honey at the rate of 5.0% (wt/vol), whereas the other half was devoid of honey and served as a control. The camel and cow milks with and without honey were subsequently inoculated with ABT-5 culture and were fermented at 37 °C until a pH value of 4.6 was reached. Thereafter, the probiotic fermented milks were cooled to 15 °C in ice water and were each separated into 18 fractions that were transferred in sterile, tightly capped centrifuge tubes. After 24 h of cooling at 8 °C (d 0), the samples were stored at refrigeration temperature (4 °C). Three tubes of all 4 products (i.e., fermented camel and cow milks with and without honey) were taken at each sampling time (i.e., following 0, 7, 14, 21, 28, and 35 d of storage), and the counts of characteristic microorganisms and those of certain spoilage microbes (yeasts, molds, coliforms, Escherichia coli) were enumerated. The entire experimental program was repeated twice. The results showed that addition of black locust honey at 5% to heat-treated camel and cow milks did not influence the growth and survival of starter streptococci during production and subsequent refrigerated storage of fermented ABT milks. In contrast, honey improved retention of viability of B. animalis ssp. lactis BB-12 in the camel milk-based product during storage at 4 °C up to 5 wk. No spoilage organisms were detected in any of the samples tested

  7. Assessment of safety of lactobacillus strains based on resistance to host innate defense mechanisms.

    PubMed

    Asahara, Takashi; Takahashi, Masatoshi; Nomoto, Koji; Takayama, Hiroo; Onoue, Masaharu; Morotomi, Masami; Tanaka, Ryuichiro; Yokokura, Teruo; Yamashita, Naoya

    2003-01-01

    Seven Lactobacillus strains belonging to four species were evaluated for pathogenicity as well as for in vitro sensitivity to the bactericidal mechanisms of macrophages in a rabbit infective endocarditis (IE) model. Two bacteremia-associated strains, L. rhamnosus PHLS A103/70 and L. casei PHLS A357/84, as well as the L. rhamnosus type strain and the probiotic L. rhamnosus strain ATCC 53103, showed moderate infectivity, and the virulence of the probiotic L. casei strain Shirota and type strains such as L. acidophilus ATCC 4356(T) and L. gasseri DSM 20243(T) in the model was negligible. The strains that showed pathogenic potential in the rabbit IE model (PHLS A357/84, PHLS A103/70, and ATCC 53103) were more resistant than strain Shirota to intracellular killing activity by mouse macrophages in vitro and also to bactericidal nitrogen intermediates, such as nitric oxide and NO(2)(-) ions. These results suggest that resistance to host innate defense systems, which would function at inflammatory lesions, should be considered in the safety assessment of Lactobacillus strains.

  8. The hsp 16 gene of the probiotic Lactobacillus acidophilus is differently regulated by salt, high temperature and acidic stresses, as revealed by reverse transcription quantitative PCR (qRT-PCR) analysis.

    PubMed

    Capozzi, Vittorio; Arena, Mattia Pia; Crisetti, Elisabetta; Spano, Giuseppe; Fiocco, Daniela

    2011-01-01

    Small heat shock proteins (sHsps) are ubiquitous conserved chaperone-like proteins involved in cellular proteins protection under stressful conditions. In this study, a reverse transcription quantitative PCR (RT-qPCR) procedure was developed and used to quantify the transcript level of a small heat shock gene (shs) in the probiotic bacterium Lactobacillus acidophilus NCFM, under stress conditions such as heat (45 °C and 53 °C), bile (0.3% w/v), hyperosmosis (1 M and 2.5 M NaCl), and low pH value (pH 4). The shs gene of L. acidophilus NCFM was induced by salt, high temperature and acidic stress, while repression was observed upon bile stress. Analysis of the 5' noncoding region of the hsp16 gene reveals the presence of an inverted repeat (IR) sequence (TTAGCACTC-N9-GAGTGCTAA) homologue to the controlling IR of chaperone expression (CIRCE) elements found in the upstream regulatory region of Gram-positive heat shock operons, suggesting that the hsp16 gene of L. acidophilus might be transcriptionally controlled by HrcA. In addition, the alignment of several small heat shock proteins identified so far in lactic acid bacteria, reveals that the Hsp16 of L. acidophilus exhibits a strong evolutionary relationship with members of the Lactobacillus acidophilus group.

  9. Detection and Specific Enumeration of Multi-Strain Probiotics in the Lumen Contents and Mucus Layers of the Rat Intestine After Oral Administration.

    PubMed

    Lee, Hee Ji; Orlovich, David A; Tagg, John R; Fawcett, J Paul

    2009-12-01

    Although the detection of viable probiotic bacteria following their ingestion and passage through the gastrointestinal tract (GIT) has been well documented, their mucosal attachment in vivo is more difficult to assess. In this study, we investigated the survival and mucosal attachment of multi-strain probiotics transiting the rat GIT. Rats were administered a commercial mixture of the intestinal probiotics Lactobacillus acidophilus LA742, Lactobacillus rhamnosus L2H and Bifidobacterium lactis HN019 and the oral probiotic Streptococcus salivarius K12 every 12 h for 3 days. Intestinal contents, mucus and faeces were tested 6 h, 3 days and 7 days after the last dose by strain-specific enumeration on selective media and by denaturing gradient gel electrophoresis. At 6 h, viable cells and DNA corresponding to all four probiotics were detected in the faeces and in both the lumen contents and mucus layers of the ileum and colon. Viable probiotic cells of B. lactis and L. rhamnosus were detected for 7 days and L. acidophilus for 3 days after the last dose. B. lactis and L. rhamnosus persisted in the ileal mucus and colon contents, whereas the retention of L. acidophilus appeared to be relatively higher in colonic mucus. No viable cells of S. salivarius K12 were detected in any of the samples at either day 3 or 7. The study demonstrates that probiotic strains of intestinal origin but not of oral origin exhibit temporary colonisation of the rat GIT and that these strains may have differing relative affinities for colonic and ileal mucosa.

  10. Probiotics cultures in animal feed: Effects on ruminal fermentation, immune responses, and resistance to infectious diseases

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We evaluated the effects of probiotics included in dairy cattle and mice feed on ruminal fermentation, immune responses, and resistance to Johne’s disease. To unveil the underlying mechanisms, dairy cattle were either fed Bovamine (1.04 x 10**9 cfu of Lactobacillus acidophilus NP51 plus 2.04 x 10**...

  11. A novel unsaturated fatty acid hydratase toward C16 to C22 fatty acids from Lactobacillus acidophilus

    PubMed Central

    Hirata, Akiko; Kishino, Shigenobu; Park, Si-Bum; Takeuchi, Michiki; Kitamura, Nahoko; Ogawa, Jun

    2015-01-01

    Hydroxy FAs, one of the gut microbial metabolites of PUFAs, have attracted much attention because of their various bioactivities. The purpose of this study was to identify lactic acid bacteria with the ability to convert linoleic acid (LA) to hydroxy FAs. A screening process revealed that a gut bacterium, Lactobacillus acidophilus NTV001, converts LA mainly into 13-hydroxy-cis-9-octadecenoic acid and resulted in the identification of the hydratase responsible, fatty acid hydratase 1 (FA-HY1). Recombinant FA-HY1 was purified, and its enzymatic characteristics were investigated. FA-HY1 could convert not only C18 PUFAs but also C20 and C22 PUFAs. C18 PUFAs with a cis carbon-carbon double bond at the Δ12 position were converted into the corresponding 13-hydroxy FAs. Arachidonic acid and DHA were converted into the corresponding 15-hydroxy FA and 14-hydroxy FA, respectively. To the best of our knowledge, this is the first report of a bacterial FA hydratase that can convert C20 and C22 PUFAs into the corresponding hydroxy FAs. These novel hydroxy FAs produced by using FA-HY1 should contribute to elucidating the bioactivities of hydroxy FAs. PMID:25966711

  12. Relative efficiency of yogurt, sweet acidophilus milk, hydrolyzed-lactose milk, and a commercial lactase tablet in alleviating lactose maldigestion.

    PubMed

    Onwulata, C I; Rao, D R; Vankineni, P

    1989-06-01

    The relative effectiveness of commercially available plain yogurt (Y), sweet acidophilus milk (SAM), hydrolyzed-lactose milk (HLM), a lactase tablet (LT), and whole milk (WM) was evaluated in 10 lactose-intolerant black subjects. In a 5 x 5 Latin square design, hourly breath hydrogen excretion (BHE) was measured for 5 h after the subjects consumed the above products (18 g lactose in each except HLM, which had 5 g). Mean BHE (ppm) for Y, SAM, LT, HLM, and WM were 12, 37, 29, 18, and 33, respectively. There was a significant (p less than 0.05) positive correlation of 0.808 between the symptoms reported and the mean peak BHE. However, the correlation between the symptoms and diagnosis by history was not significant. Although Y was as effective as HLM in minimizing lactose maldigestion, it was the least accepted by the subjects in sensory evaluations. Results of this study also indicate that microbial endogenous lactase in yogurt is superior to exogenous commercial lactase in alleviating lactose maldigestion.

  13. Yogurt containing bioactive molecules produced by Lactobacillus acidophilus La-5 exerts a protective effect against enterohemorrhagic Escherichia coli in mice.

    PubMed

    Zeinhom, Mohamed; Tellez, Angela M; Delcenserie, Veronique; El-Kholy, A M; El-Shinawy, S H; Griffiths, Mansel W

    2012-10-01

    An active fraction extracted from Lactobacillus acidophilus La5 cell-free spent medium (LAla-5AF) was incorporated in a dairy matrix and tested to assess its antivirulent effect against enterohemorrhagic Escherichia coli (EHEC). Mice in experimental groups were fed for 4 days with yogurt supplemented with LAla-5AF. On the fifth day, mice were challenged with a single dose (10(7) CFU per mouse) of E. coli O157:H7. The clinical manifestations of the infection were significantly less severe in mice fed the yogurt supplemented with LAla-5AF. EHEC attachment and colonization was attenuated by LAla-5AF. Tumor necrosis factor alpha production was down-regulated, which might indicate a protective effect in the kidney during EHEC infection. To investigate the mechanisms associated with the in vivo effects observed, LAla-5AF was tested by reverse transcription real-time PCR to confirm its effects on the expression of several virulence genes of EHEC O157. The results showed that these fractions were able to down-regulate several virulence genes of EHEC, including stxB2, qseA, luxS, tir, ler, eaeA, and hlyB.

  14. Strain Gage

    NASA Technical Reports Server (NTRS)

    1995-01-01

    HITEC Corporation developed a strain gage application for DanteII, a mobile robot developed for NASA. The gage measured bending forces on the robot's legs and warned human controllers when acceptable forces were exceeded. HITEC further developed the technology for strain gage services in creating transducers out of "Indy" racing car suspension pushrods, NASCAR suspension components and components used in motion control.

  15. Egg quality and productive performance of laying hens fed different levels of skimmed milk powder added to a diet containing Lactobacillus acidophilus.

    PubMed

    Cesari, V; Mangiagalli, M G; Giardini, A; Galimberti, P; Carteri, S; Gallazzi, D; Toschi, I

    2014-05-01

    The current trial was carried out on a commercial poultry farm to study the effect of skim milk powder (SMP) added to a diet containing Lactobacillus acidophilus on performance and egg quality of laying hens from 20 to 49 wk of age. A total of 2,400 Hy-Line W-36 laying hens were housed in 600 unenriched cages (4 hens each) located over 4 tier levels. Animals were assigned to 1 of 3 experimental treatments (0, 3, and 4). The laying hens assigned to treatments 3 and 4 received a diet enriched respectively with 3 and 4% SMP, whereas the animals in treatment 0 were fed a diet without SMP. All diets, moreover, were supplemented with L. acidophilus D2/CSL. Hen performance was determined throughout the experimental period and egg quality was measured on 30 eggs per treatment every week. Results showed that productive performance in terms of egg production, egg weight, and feed conversion ratio was not influenced by SMP at 3 or 4% of the diet. Egg quality was significantly affected by SMP included at 3 or 4% of the diet. Eggs from treatments 3 and 4, in fact, displayed higher shell thickness than those from treatment 0 (P < 0.0001). Likewise, specific gravity, Haugh unit, and shell percentage were significantly affected by the addition of SMP. In conclusion, in our study, SMP added to a diet containing L. acidophilus had no significant effects on the productive parameters of hens during the laying period, whereas significant improvements were found in certain egg quality characteristics.

  16. Selective and differential enumerations of Lactobacillus delbrueckii subsp. bulgaricus, Streptococcus thermophilus, Lactobacillus acidophilus, Lactobacillus casei and Bifidobacterium spp. in yoghurt--a review.

    PubMed

    Ashraf, Rabia; Shah, Nagendra P

    2011-10-03

    Yoghurt is increasingly being used as a carrier of probiotic bacteria for their potential health benefits. To meet with a recommended level of ≥10(6) viable cells/g of a product, assessment of viability of probiotic bacteria in market preparations is crucial. This requires a working method for selective enumeration of these probiotic bacteria and lactic acid bacteria in yoghurt such as Streptococcus thermophilus, Lactobacillus delbrueckii subsp. bulgaricus, Lb. acidophilus, Lb. casei and Bifidobacterium. This chapter presents an overview of media that could be used for differential and selective enumerations of yoghurt bacteria. De Man Rogosa Sharpe agar containing fructose (MRSF), MRS agar pH 5.2 (MRS 5.2), reinforced clostridial prussian blue agar at pH 5.0 (RCPB 5.0) or reinforced clostridial agar at pH 5.3 (RCA 5.3) are suitable for enumeration of Lb. delbrueckii subsp. bulgaricus when the incubation is carried out at 45°C for 72h. S. thermophilus (ST) agar and M17 are recommended for selective enumeration of S. thermophilus. Selective enumeration of Lb. acidophilus in mixed culture could be made in Rogosa agar added with 5-bromo-4-chloro-3-indolyl-β-d-glucopyranoside (X-Glu) or MRS containing maltose (MRSM) and incubation in a 20% CO2 atmosphere. Lb. casei could be selectively enumerated on specially formulated Lb. casei (LC) agar from products containing yoghurt starter bacteria (S. thermophilus and Lb. delbrueckii subsp. bulgaricus), Lb. acidophilus, Bifidobacterium spp. and Lb. casei. Bifidobacterium could be enumerated on MRS agar supplemented with nalidixic acid, paromomycin, neomycin sulphate and lithium chloride (MRS-NPNL) under anaerobic incubation at 37°C for 72h.

  17. Antimicrobial efficacy of Acacia nilotica, Murraya koenigii (L.) Sprengel, Eucalyptus hybrid, Psidium guajava extracts and their combination on Streptococcus mutans and Lactobacillus acidophilus

    PubMed Central

    Chandra Shekar, B. R.; Nagarajappa, Ramesh; Jain, Richa; Singh, Rupal; Thakur, Rupesh; Shekar, Suma

    2016-01-01

    Background: The aim of this in vitro study was to assess antimicrobial efficacy of Acacia nilotica, Murraya koenigii (L.) Sprengel, Eucalyptus hybrid, Psidium guajava extracts, and their combination on Streptococcus mutans and Lactobacillus acidophilus. Materials and Methods: The branches of four plants were collected, identified, and authenticated by a taxonomist. The plants were rinsed in water, healthy leaves were separated and shade dried over a period of 3-4 weeks. Soxhlet apparatus using ethanol was employed for extraction procedure. The combinations of plant extracts were prepared by mixing equal quantities of 10% solutions of each of these extracts. 0.2% chlorhexidine and dimethyl sulfoxide were used as positive and negative controls, respectively. The antimicrobial efficacy testing was done using agar well-diffusion method under anaerobic conditions. The mean diameter of inhibition zone was computed and compared between different categories using one-way analysis of variance and Tukey's post-hoc test. A qualitative assay was carried out to identify the various phytochemical constituents in the plants. The data was assessed by SPSS version 20. The statistical significance was fixed at 0.05. Results: All the plants extracts and their combinations inhibited S. mutans and L. acidophilus. However, the quadruple combination of A. nilotica + M. koenigii (L.) Sprengel + Eucalyptus hybrid + P. guajava produced the maximum inhibition zone (23.5 ± 2.2 mm) against S. mutans. Although, 0.2% chlorhexidine produced the highest inhibition zone against L. acidophilus (18.8 ± 1.2 mm), A. nilotica extract produced maximum inhibition among the various plant extracts and their combinations (14.1 ± 1.8 mm). Conclusion: All the individual plant extracts and their combinations were effective against S. mutans and L. acidophilus. These could be tried as herbal alternates to chlorhexidine. However, these in vitro results have to be further evaluated for any toxicity of the

  18. Lactate- and acetate-based cross-feeding interactions between selected strains of lactobacilli, bifidobacteria and colon bacteria in the presence of inulin-type fructans.

    PubMed

    Moens, Frédéric; Verce, Marko; De Vuyst, Luc

    2017-01-16

    Cross-feeding interactions were studied between selected strains of lactobacilli and/or bifidobacteria and butyrate-producing colon bacteria that consume lactate but are not able to degrade inulin-type fructans (ITF) in a medium for colon bacteria (supplemented with ITF as energy source and acetate when necessary). Degradation of oligofructose by Lactobacillus acidophilus IBB 801 and inulin by Lactobacillus paracasei 8700:2 and Bifidobacterium longum LMG 11047 resulted in the release of free fructose into the medium and the production of mainly lactate (lactobacilli) and acetate (B. longum LMG 11047). During bicultures of Lb. acidophilus IBB 801 and Anaerostipes caccae DSM 14662(T) on oligofructose, the latter strain converted lactate (produced by the former strain from oligofructose) into butyrate and gases, but only in the presence of acetate. During bicultures of Lb. paracasei 8700:2 and A. caccae DSM 14662(T) or Eubacterium hallii DSM 17630 on inulin, the butyrate-producing strains consumed low concentrations of lactate and acetate generated by inulin degradation by the Lactobacillus strain. As more acetate was produced during tricultures of Lb. paracasei 8700:2 and B. longum LMG 11047, which degraded inulin simultaneously, and A. caccae DSM 14662(T) or E. hallii DSM 17630, a complete conversion of lactate into butyrate and gases by these butyrate-producing strains occurred. Therefore, butyrate production by lactate-consuming, butyrate-producing colon bacterial strains incapable of ITF degradation, resulted from cross-feeding of monosaccharides and lactate by an ITF-degrading Lactobacillus strain and acetate produced by a Bifidobacterium strain.

  19. Preservative effect of food-based fermentate from Lactobacillus acidophilus NX2-6 on chilled pork patties.

    PubMed

    Zhang, Qianying; Lu, Yingjian; Liu, Xiaoxi; Bie, Xiaomei; Lv, Fengxia; Lu, Zhaoxin

    2014-03-01

    The food-based fermentate (FBF) from Lactobacillus acidophilus NX2-6 has a broad-spectrum antibacterial activity but has not previously been reported as a food preservative. Experiments were conducted to assess its application as a preservative in pork patties. The effect of freeze-dried FBF on the microbiological parameters, physicochemical changes, and sensory evaluations of chilled pork patties stored for 15 days at 4°C was investigated. The five treatments evaluated included a control (meat only), nisin (meat plus 0.5% nisin), L.1 (meat plus 2% freeze-dried FBF), L.2 (meat plus 4% freeze-dried FBF), and L.3 (meat plus 8% freeze-dried FBF). The results showed that freeze-dried FBF could significantly (P < 0.05) inhibit aerobic bacteria, coliforms, Pseudomonas spp., and lactic acid bacteria, with the lowest microbial counts observed in L.3. The addition of freeze-dried FBF resulted in concentration-dependent decreases in total volatile basic nitrogen values and pH values but increases in lipid oxidation and color instability. Based on the criteria regarding microbiological and physicochemical parameters, the shelf life was 9 to 12 days for L.1, 12 to 15 days for L.2, and over 15 days for L.3, while the shelf-lives of the control and nisin treatments were 3 to 6 days, indicating that freeze-dried FBF could extend the shelf life by more than 3 days. Although the shelf life of L.1 was shorter than those of L.2 and L.3, the appearance of L.1 was much better than those of L.2 and L.3. Overall, treatment with 4 or 8% freeze-dried FBF could be improved if color and lipid oxidation could be improved by appropriate stabilizers, and a lower concentration (2%) of freeze-dried FBF has great potential as a natural and safe preservative in chilled pork patties.

  20. Evaluation of the Effect of Psyllium on the Viability of Lactobacillus Acidophilus in Alginate-Polyl Lysine Beads

    PubMed Central

    Esmaeilzadeh, Jaleh; Nazemiyeh, Hossein; Maghsoodi, Maryam; Lotfipour, Farzaneh

    2016-01-01

    Purpose: Psylliumseeds are used in traditional herbal medicine to treat various disorders. Moreover, as a soluble fiber, psyllium has potential to stimulate bacterial growth in digestive system. We aimed to substitute alkali-extractable polysaccharides of psyllium for alginate in beads with second coat of poly-l-lysine to coat Lactobacillus acidophilus. Methods: Beads were prepared using extrusion technique. Poly-l-lysine as second coat was incorporated on optimum alginate/psyllium beads using immersion technique. Beads were characterized in terms of size, encapsulation efficiency, integrity and bacterial survival in harsh conditions. Results: Beads with narrow size distribution ranging from 1.85 ± 0.05 to 2.40 ± 0.18 mm with encapsulation efficiency higher than 96% were achieved. Psyllium concentrations in beads did not produce constant trend in bead sizes. Surface topography by SEM showed that substitution of psyllium enhanced integrity of obtained beads. Psyllium successfully protected the bacteria against acidic condition and lyophilization equal to alginate in the beads. Better survivability with beads of alginate/psyllium-poly-l-lysine was achieved with around 2 log rise in bacterial count in acid condition compared to the corresponding single coat beads. Conclusion: Alginate/psyllium (1:2) beads with narrow size distribution and high encapsulation efficiency of the bacteria have been achieved. Presence of psyllium produced a much smoother and integrated surface texture for the beads with sufficient protection of the bacteria against acidic condition as much as alginate. Considering the health benefits of psyllium and its prebiotic activity, psyllium can be beneficially replaced in part for alginate in probiotic coating. PMID:27766217

  1. Gut microbiota of healthy elderly NSAID users is selectively modified with the administration of Lactobacillus acidophilus NCFM and lactitol.

    PubMed

    Björklund, Marika; Ouwehand, Arthur C; Forssten, Sofia D; Nikkilä, Janne; Tiihonen, Kirsti; Rautonen, Nina; Lahtinen, Sampo J

    2012-08-01

    Ageing changes gut microbiota composition and alters immune system function. Probiotics, prebiotics and synbiotics may improve the health status of elderly individuals by modifying the intestinal environment and the microbiota composition, and by stimulating the immune system. In this work, we studied the effects of synbiotic supplementation on the gut microbiota of healthy elderly volunteers. Fifty-one elders were randomly assigned to consume either a synbiotic dietary supplement or a placebo in addition to their usual diet for a 2-week period. The synbiotic product consisted of the probiotic Lactobacillus acidophilus NCFM and the prebiotic lactitol and was ingested twice a day, with a total daily dose of 10 g lactitol and 2 × 10(10) cells of probiotic bacteria. Before, during and after the intervention period fecal quantities of six phylogenetic bacterial groups were determined using quantitative PCR, and relative changes in total microbiota composition were assessed by percent guanine-plus-cytosine profiling. The microbiota profiles showed certain relative changes within the microbial community, and indicated an increase of bifidobacteria levels during synbiotic supplementation. Quantification by PCR confirmed the in changes in the microbiota composition; for example increases in total levels of endogenous bifidobacteria and lactobacilli were recorded. Throughout the 6-week study period there was a decrease unrelated to intervention in the Blautia coccoides-Eubacterium rectale bacterial group levels and Clostridium cluster XIVab levels, but this decrease appeared to be halted during the synbiotic intervention. In conclusion, putatively beneficial changes in microbiota were observed in the elderly subjects supplemented with the synbiotic product.

  2. Effect of moderate electric field frequency and growth stage on the cell membrane permeability of Lactobacillus acidophilus.

    PubMed

    Loghavi, Laleh; Sastry, Sudhir K; Yousef, Ahmed E

    2009-01-01

    Changes in growth kinetics and metabolic activity of microorganisms under the presence of a moderate electric field (MEF) have been hypothesized as being due to temporary permeabilization of cell membranes. We investigated herein the effects of frequency and growth stage on cell membrane permeabilization of Lactobacillus acidophilus OSU 133 during MEF fermentation. Cells were stained with two fluorescent nucleic acid stains: the green, nonselective, cell membrane permeable SYTO 9, and the red, cell membrane impermeable propidium iodide (PI). Fluorescence exhibition post-treatment was assessed using fluorescence microscopy. Total plate counting was done to determine whether or not the permeabilized population represented live cells. Fermentation treatments investigated were conventional (control) and MEF (2 V/cm, 45, 60, 1,000, 10,000 Hz) at 30 degrees C. Studies were conducted at 45 Hz for lag, exponential, and stationary phases of growth. Low frequency MEF treated cells exhibited significantly greater numbers of red cell counts than conventional treatments; further, no significant differences existed in viable counts between MEF and conventional treatments, suggesting that the red counts represent permeabilized live cells. MEF treatments at the early stage of bacterial growth at 45 Hz exhibited the maximum permeabilization followed by treatments at 60 Hz. MEF treated samples at frequencies higher than 60 Hz did not exhibit red fluorescence. Cells at lag phase showed the greatest susceptibility to permeabilization followed by those at exponential phase. No evidence of electroporation was observed during the stationary phase. To our knowledge, these observations provide the first evidence that cell membrane permeabilization occurs under the presence of electric fields as low as those under MEF.

  3. The structure and immunomodulatory activity on intestinal epithelial cells of the EPSs isolated from Lactobacillus helveticus sp. Rosyjski and Lactobacillus acidophilus sp. 5e2.

    PubMed

    Patten, Daniel A; Leivers, Shaun; Chadha, Marcus J; Maqsood, Mohammed; Humphreys, Paul N; Laws, Andrew P; Collett, Andrew

    2014-01-30

    The Lactic acid bacteria (LAB) Lactobacillus acidophilus sp. 5e2 and Lactobacillus helveticus sp. Rosyjski both secrete exopolysaccharides (EPSs) into their surrounding environments during growth. A number of EPSs have previously been shown to exhibit immunomodulatory activity with professional immune cells, such as macrophages, but only limited studies have been reported of their interaction with intestinal epithelial cells. An investigation of the immunomodulatory potential of pure EPSs, isolated from cultures of Lactobacillus acidophilus sp. 5e2 and Lactobacillus helveticus sp. Rosyjski, with the HT29-19A intestinal epithelial cell line are reported here. For the first time the structure of the EPS from Lactobacillus helveticus sp. Rosyjski which is a hetropolysaccharide with a branched pentasaccharide repeat unit containing d-glucose, d-galactose and N-acetyl-d-mannosamine is described. In response to exposure to lactobacilli EPSs HT29-19A cells produce significantly increased levels of the proinflammatory cytokine IL-8. Additionally, the EPSs differentially modulate the mRNA expression of Toll-like receptors. Finally, the pre-treatment of HT29-19A cells with the EPSs sensitises the cells to subsequent challenge with bacterial antigens. The results reported here suggest that EPSs could potentially play a role in intestinal homeostasis via a specific interaction with intestinal epithelial cells.

  4. Production of 13S-hydroxy-9(Z)-octadecenoic acid from linoleic acid by whole recombinant cells expressing linoleate 13-hydratase from Lactobacillus acidophilus.

    PubMed

    Park, Ji-Young; Lee, Seon-Hwa; Kim, Kyoung-Rok; Park, Jin-Byung; Oh, Deok-Kun

    2015-08-20

    Linoleate 13-hydratase from Lactobacillus acidophilus LMG 11470 converted linoleic acid to hydroxyl fatty acid, which was identified as 13S-hydroxy-9(Z)-octadecenoic acid (13-HOD) by GC-MS and NMR. The expression of linoleate 13-hydratase gene in Escherichia coli was maximized by using pACYC plasmid and super optimal broth with catabolite repression (SOC) medium containing 40mM Mg(2+). To optimize induction conditions, recombinant cells were cultivated at 37°C, 1mM isopropyl-β-d-thiogalactopyranoside was added at 2h, and the culture was further incubated at 16°C for 18h. Recombinant cells expressing linoleate 13-hydratase from L. acidophilus were obtained under the optimized expression conditions and used for 13-HOD production from linoleic acid. The optimal reaction conditions were pH 6.0, 40°C, 0.25% (v/v) Tween 40, 25gl(-1) cells, and 100gl(-1) linoleic acid, and under these conditions, whole recombinant cells produced 79gl(-1) 13-HOD for 3h with a conversion yield of 79% (w/w), a volumetric productivity of 26.3gl(-1)h(-1), and a specific productivity of 1.05g g-cells(-1)h(-1). To the best of our knowledge, the recombinant cells produced hydroxy fatty acid with the highest concentration and productivity reported so far.

  5. Effect of salt on cell viability and membrane integrity of Lactobacillus acidophilus, Lactobacillus casei and Bifidobacterium longum as observed by flow cytometry.

    PubMed

    Gandhi, Akanksha; Shah, Nagendra P

    2015-08-01

    The aim of the current study was to investigate the effect of varying sodium chloride concentrations (0-5%) on viability and membrane integrity of three probiotic bacteria, Lactobacillus acidophilus, Lactobacillus casei and Bifidobacterium longum, using conventional technique and flow cytometry. Double staining of cells by carboxyfluorescein diacetate (cFDA) and propidium iodide (PI) enabled to evaluate the effect of NaCl on cell esterase activity and membrane integrity. Observations from conventional culture technique were compared with findings from flow cytometric analysis on the metabolic activities of the cells and a correlation was observed between culturability and dye extrusion ability of L. casei and B. longum. However, a certain population of L. acidophilus was viable as per the plate count method but its efflux activity was compromised. Esterase activity of most bacteria reduced significantly (P < 0.05) during one week storage at NaCl concentrations greater than 3.5%. The study revealed that L. casei was least affected by higher NaCl concentrations among the three probiotic bacteria, as opposed to B. longum where the cF extrusion performance was greatly reduced during 1 wk storage. The metabolic activity and salt resistance of L. casei was found to be highest among the bacteria studied.

  6. Lactobacillus acidophilus Increases the Anti-apoptotic Micro RNA-21 and Decreases the Pro-inflammatory Micro RNA-155 in the LPS-Treated Human Endothelial Cells.

    PubMed

    Kalani, Mehdi; Hodjati, Hossein; Sajedi Khanian, Mahdi; Doroudchi, Mehrnoosh

    2016-06-01

    Given the anti-inflammatory and protective role of probiotics in atherosclerosis and the regulatory role of micro RNA (miRNA) in endothelial cell (dys) functions, this study aimed to investigate the effect of Lactobacillus acidophilus (La) on cellular death and the expression of miRNA-21, 92a, 155, and 663 in human umbilical vein endothelial cell (HUVEC) induced by Escherichia coli lipopolysaccharide (Ec-LPS). LPS-treated and untreated HUVECs were cultured in the presence of different La conditions such as La-conditioned media (LaCM), La water extract (LaWE), La culture-filtered (LaFS) and unfiltered supernatants (LaUFS). After 24 h, apoptosis, necrosis and the levels of the mentioned miRNAs were measured using flow cytometry and real-time PCR methods, respectively. LaCM decreased apoptosis, necrosis and inflammatory miR-155 and conversely increased anti-apoptotic miR-21 in Ec-LPS-treated HUVECs. Association analysis revealed negative correlations between necrosis and the levels of miR-21, miR-92a, and miR-155. The beneficial effects of L. acidophilus on the ECs death and expression of atherosclerosis related miRNAs in these cells imply a new aspect of its regulation in cardiovascular diseases rather than previously described ones and suggest this probiotic bacterium as a candidate in the preventative therapy of atherosclerosis.

  7. Effects of bile salt deconjugation by probiotic strains on the survival of antibiotic-resistant foodborne pathogens under simulated gastric conditions.

    PubMed

    He, Xinlong; Zou, Yunyun; Cho, Youngjae; Ahn, Juhee

    2012-06-01

    This study was designed to evaluate the effects of bile acid deconjugation by probiotic strains on the antibiotic susceptibility of antibiotic-sensitive and multiple antibiotic-resistant Salmonella Typhimurium and Staphylococcus aureus. Eight probiotic strains, Bifidobacterium longum B6, Lactobacillus acidophilus ADH, Lactobacillus brevis KACC 10553, Lactobacillus casei KACC 12413, Lactobacillus paracasei ATCC 25598, Lactobacillus rhamnosus GG, Leuconostoc mesenteroides KACC 12312, and Pediococcus acidilactici KACC 12307, were used to examine bile acid tolerance. The ability to deconjugate bile acids was evaluated using both thin-layer chromatography and high-performance liquid chromatography. The antibiotic susceptibility testing was carried out to determine the synergistic inhibitory activity of deconjugated bile acids. L. acidophilus, L. brevis, and P. acidilactici showed the most tolerance to the conjugated bile acids. P. acidilactici deconjugated glycocholic acid and glycodeoxycholate from 3.18 and 3.09 mM to the detection limits, respectively. The antibiotic susceptibility of selected foodborne pathogens was increased by increasing the concentration of deconjugated bile acids. The study results are useful for understanding the relationship between bile acid deconjugation by probiotic strains and antibiotic susceptibility in the presence of deconjugated bile acids, and they may be useful for designing new probiotic-antibiotic combination therapy based on bile acid deconjugation.

  8. Yogurt Containing the Probacteria Lactobacillus acidophilus Combined with Natural Antioxidants Mitigates Doxorubicin-Induced Cardiomyopathy in Rats.

    PubMed

    Abu-Elsaad, Nashwa M; Abd Elhameed, Ahmed G; El-Karef, Amr; Ibrahim, Tarek M

    2015-09-01

    Probiotics and antioxidants have a definite improving effect in cardiovascular diseases. This study aims at mitigating doxorubicin toxicity on cardiac function through consuming a functional food. Five groups of adult male Sprague-Dawley rats were used along 22 weeks. Group I received 30 g/kg/day food enriched with yogurt, green tea extract, and carrots (80, 0.84, and 100 g/kg diet, respectively) from the first week, group II received carvedilol 30 mg/kg/day orally from week 17, group III received both carvedilol and tested food, and groups IV and V were +ve and -ve control groups, respectively. In week 17, cardiomyopathy was induced by i.p. injection of 2.5 mg/kg doxorubicin every 48 h for 2 weeks. Histopathological and electrophysiological examinations and biochemical analysis were done. Lipid peroxidation, antioxidant effect, heart failure compensatory mediators, and proinflammatory cytokines were assessed. Tested food normalized time between the start of Q wave and the end of T wave on electrocardiogram (QT interval) and heart rate compared to the doxorubicin group (P<.05). It also improved hypertrophy indicated by a significant (P<.05) decrease in heart/body weight ratio, angiotensin-II (Ang-II), and atrial natriuretic peptide (ANP) serum levels. Histopathological examination of cardiac sections from the tested food group revealed less marked vacuolization and low perivascular fibrosis percentage (0.7803 ± 0.04). A significant (P<.001) decrease in serum creatine kinase-membrane bound, lactate dehydrogenase, triglycerides, cholesterol, low-density lipoprotein cholesterol, and tissue malondialdehyde (MDA) levels was observed in addition to an increase in serum Na(+)/K(+) ATP1A1 and cardiac reduced glutathione (GSH) levels. Tested food also lowered the inflammatory cytokines tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) serum levels significantly (P<.01). Probiotic food containing Lactobacillus acidophilus, green tea, and carrots can improve

  9. Effects of Lactobacillus acidophilus dietary supplementation on the performance, intestinal barrier function, rectal microflora and serum immune function in weaned piglets challenged with Escherichia coli lipopolysaccharide.

    PubMed

    Qiao, Jiayun; Li, Haihua; Wang, Zhixiang; Wang, Wenjie

    2015-04-01

    This study was conducted with a lipopolysaccharide (LPS)-challenged piglet model to determine the effects of diets containing Lactobacillus acidophilus on the performance, intestinal barrier function, rectal microflora and serum immune function. A total of 150 piglets (initial body weight (BW) 7.53 ± 0.21 kg) were allotted to one of the following diets, including a basal diet, a basal diet supplemented with 250 mg/kg Flavomycin, or basal diet plus 0.05, 0.1 or 0.2 % L. acidophilus. On day 28 of the trial, the pigs were given an intraperitoneal injection of LPS (200 μg/kg body weight) followed by blood collection 3 h later. Diets with either antibiotics, 0.1 or 0.2 % Lactobacillus increased (P < 0.05) the final BW and decreased (P < 0.05) feed gain ratio (F/G) compared with the control group. Pigs fed diets containing antibiotic or Lactobacillus had greater average daily gain (ADG) (P < 0.05) than pigs fed the control diet. The rectal content Lactobacillus counts for pigs fed diet containing Lactobacillus were significant higher (P < 0.01) than those fed antibiotic or control diet. Feeding the Lactobacillus diets decreased the Escherichia coli counts of rectal content (P < 0.01). Pigs fed diets containing 0.1 or 0.2 % Lactobacillus decreased serum DAO activity (P < 0.05) compared with pigs fed the control diet. Serum IL-10 concentration was enhanced in pigs fed the diet with Lactobacillus compared to pigs fed the control diet and antibiotic diet. Feeding a diet with Lactobacillus reduced (P < 0.05) IFN-γ concentration compared to the control diet. Inclusion of Lactobacillus in diets fed to pigs reduced TNF-α concentration compared with pigs fed no Lactobacillus (P < 0.05). These results indicate that feeding with L. acidophilus improved growth performance and protected against LPS-induced inflammatory status.

  10. Regulation of the Lactobacillus Strains on HMGCoA Reductase Gene Transcription in Human HepG2 Cells via Nuclear Factor-κB.

    PubMed

    Chen, Kun; Li, Shaocong; Chen, Fang; Li, Jun; Luo, Xuegang

    2016-02-01

    Lactic acid bacteria have been identified to be effective in reducing cholesterol levels. Most of the mechanistic studies were focused on the bile salt deconjugation ability of bile salt hydrolase in lactic acid bacteria. However, the mechanism by which Lactobacillus decreases cholesterol levels has not been thoroughly studied in intact primate cells. 3-Hydroxy-3- methyl-glutaryl-coenzyme A reductase (HMGCR) is the vital enzyme in cholesterol synthesis. To confirm the effect of probiotic Lactobacillus strains on HMGCR level, in the present study, human hepatoma HepG2 cells were treated with Lactobacillus strains, and then the HMGCR level was illustrated by luciferase reporter assay and RT-PCR. The results showed that the level of HMGCR was suppressed after being treated with the live Lactobacillus strains. These works might set a foundation for the following study of the antihyperlipidemic effects of L. acidophilus, and contribute to the development of functional foods or drugs that benefit patients suffering from hyperlipidemia diseases.

  11. Novel encapsulation improves recovery of probiotic strains in fecal samples of human volunteers.

    PubMed

    Mai, Volker; Waugh, Sheldon; Byrd, Doratha; Simpson, Damion; Ukhanova, Maria

    2017-02-01

    Probiotic supplements can contribute to maintaining health and ameliorating various disease symptoms. Probiotics can be delivered in many forms with crucial differences in their survival during gastrointestinal (GI) passage. Previously, a novel encapsulation, Probiotic Pearls™ Acidophilus, Integrative Therapeutics, LLC, USA (Pearls), was shown to increase survival in vitro after exposure to gastric conditions. Here, we compare fecal recovery in human volunteers consuming Pearls or a conventional hard-shelled gelatin capsule. We performed a randomized double-blinded, two-armed trial, with six healthy subjects in each 12-day study arm. In fecal samples collected at baseline, twice during the intervention period, and after washout, we compared colony counts between the two encapsulation methods. The identity of the colonies was confirmed by colony morphology, strain-specific PCR, and 16S rRNA gene sequencing. We further performed a comprehensive 16S rRNA gene sequencing-based analysis to identify differential effects on overall microbiota composition. We detected an average log increase in bifidobacteria of 0.152 cfu/g with gelatin and 0.651 cfu/g with Pearls capsules (p > 0.05). Total lactobacilli counts increased in both groups with no difference between the groups. However, the supplemented Lactobacillus acidophilus NCFM decreased to baseline levels within 7 days after end of supplementation with gelatin capsules while 3.11 log cfu/g higher counts compared to baseline (p = 0.05) remained for Pearls. Targeted qPCR largely confirmed the trends observed by viable plate counts. Protecting the probiotic strains by Pearls encapsulation results in higher recovery rates of the supplemented lactobacilli and bifidobacteria in fecal samples and increased persistence, suggesting an improved survival and viability that might increase efficacy towards achieving desired health benefits.

  12. Effect of denak (Oliveria decumbens Vent) on growth and survival of Lactobacillus acidophilus and Bifidobacterium bifidum for production of probiotic herbal milk and yoghurt.

    PubMed

    Ehsandoost, E; Gholami, S P; Nazemi, M

    2013-12-15

    This study was undertaken to determine the suitability of different doses (0, 0.5, 1.0 and 1.5%) of Denak powder (Oliveria decumbens Vent) on viability of Lactobacillus acidophilus and Bifidobacterium bifidum in milk and yoghurt during 21 day refrigerated storage for production of probiotic herbal milk and yoghurt. In order to determine the effect of different doses of Denak powder on growth of probiotic bacteria in milk and yoghurt, first lyophilized bacteria Lactobacillus acidophilus was added to 1 liter of low fat sterilized milk and was considered as control. Denak powder at the concentrations of 0.5, 1 and 1.5% were added to the samples and incubated until acidity reached 40 degrees Dornic and then left in refrigerator. Similar procedure was applied to the bacteria Bifidobacterium bifidum. The results of this experiment indicate the positive correlation between increased bacterial growth and increased Denak concentration. The investigation showed that the yoghurt containing 1% Denak powder had the best for taste, color, and insolubility. The sample with 1.5% Denak powder in milk and yoghurt had greater viscosity than the other samples investigated. The shelf lives of products were determined to be 21 days during which the bacterial count decreased but not less than 10(9). All the results suggest that Denak (Oliveria decumbens Vent) promoted the metabolism of lactic acid bacteria in milk and yoghurt. According to these findings, addition of Denak powder to milk and yoghurt can be recommended to take advantage of their beneficial properties on human health attributed to antimicrobial activities.

  13. Oral Immunization with Recombinant Lactobacillus acidophilus Expressing espA-Tir-M Confers Protection against Enterohemorrhagic Escherichia coli O157:H7 Challenge in Mice

    PubMed Central

    Lin, Ruqin; Zhang, Yiduo; Long, Beiguo; Li, Yawen; Wu, Yuhua; Duan, Siqin; Zhu, Bo; Wu, Xianbo; Fan, Hongying

    2017-01-01

    Enterohemorrhagic Escherichia coli O157:H7 (EHEC O157:H7) causes hemorrhagic colitis and the formation of characteristic attaching and effacing (A/E) lesions in humans. Given the severe sequelae of EHEC O157:H7 infection, it is critical to develop effective vaccines for human use. However, for achieving this goal many hurdles need to be addressed, such as the type or subset of antigens, adjuvant, and the delivery route. We developed a candidate vaccine by inserting the bivalent antigen espA-Tir-M composed of espA and the Tir central domain into Lactobacillus acidophilus. The recombinant L. acidophilus (LA-ET) was safe in a cell model and excluded EHEC O157:H7 from LoVo cells at rates of nearly 94 and 60% in exclusion and competition assays, respectively. LA-ET inhibited the induction of A/E lesions by EHEC O157:H7 cells in vitro. Oral immunization with LA-ET induced higher levels of specific mucosal and systemic antibody responses in mice. Moreover, LA-ET enhanced interferon-γ and interleukin-4 and -10 production, which was associated with mixed helper T (Th1/Th2) cell responses, and protected against EHEC O157:H7 colonization and infection in mice at a rate of 80%. Histopathological analyses revealed that orally administered LA-ET reduced or inhibited A/E lesions and toxin-induced systemic injury. These findings demonstrate that LA-ET induces both humoral and cellular immune responses in mice and is therefore a promising vaccine against EHEC O157:H7 infection. PMID:28360900

  14. Acute oral toxicity and bacterial translocation studies on potentially probiotic strains of lactic acid bacteria.

    PubMed

    Zhou, J S; Shu, Q; Rutherfurd, K J; Prasad, J; Gopal, P K; Gill, H S

    2000-01-01

    Three potentially probiotic lactic acid bacteria (LAB) strains, Lactobacillus rhamnosus HN001 (DR20(TM)), Lb. acidophilus HN017 and Bifidobacterium lactis HN019 (DR10()), have recently been identified and characterized. The present study was designed to evaluate the acute oral toxicity of these strains to mice, and also to investigate bacterial translocation and gut mucosal pathology in BALB/c mice fed HN019, HN001 or HN017 for 8 consecutive days at a high dose of 10(11)cfu/mouse/day. Results showed that these probiotic strains had no adverse effect on general health status, feed intake, body weight gain and intestinal mucosal morphology (villus height, crypt depth, epithelial cell height and mucosal thickness). No viable bacteria were recovered from blood and tissue samples (mesenteric lymph nodes, liver and spleen) of mice, and no treatment-associated illness or death was observed. According to these results, the oral LD(50) of HN019, HN001 and HN017 is more than 50g/kg/day for mice, and their acceptable daily intake (ADI) value is 35g dry bacteria per day for a 70-kg person. This suggests that the probiotic strains HN019, HN001 and HN017 are non-pathogenic and likely to be safe for human consumption.

  15. Influence of the addition of Lactobacillus acidophilus La-05, Bifidobacterium animalis subsp. lactis Bb-12 and inulin on the technological, physicochemical, microbiological and sensory features of creamy goat cheese.

    PubMed

    Barbosa, Ilsa C; Oliveira, Maria E G; Madruga, Marta S; Gullón, Beatriz; Pacheco, Maria T B; Gomes, Ana M P; Batista, Ana S M; Pintado, Maria M E; Souza, Evandro L; Queiroga, Rita C R E

    2016-10-12

    The effects of the addition of Lactobacillus acidophilus LA-05, Bifidobacterium animalis subsp. lactis BB-12 and inulin on the quality characteristics of creamy goat cheese during refrigerated storage were evaluated. The manufactured cheeses included the addition of starter culture (Lactococcus lactis subsp. lactis and Lactococcus lactis subsp. cremoris - R-704) (CC); starter culture, L. acidophilus LA-05 and inulin (CLA); starter culture, B. lactis BB-12 and inulin (CBB); or starter culture, L. acidophilus LA-05, B. lactis BB-12 and inulin (CLB). In the synbiotic cheeses (CLA, CBB and CLB), the counts of L. acidophilus LA-05 and B. lactis BB-12 were greater than 6log CFU g(-1), the amount of inulin was greater than 6 g per 100 g, and the firmness was reduced. The cheeses evaluated had high brightness values (L*), with a predominance of yellow (b*). CC had higher contents of proteins, lipids and minerals compared to the other cheeses. There was a decrease in the amount of short-chain fatty acids (SCFAs) and an increase of medium-chain (MCFAs) and long-chain fatty acids (LCFAs) in the synbiotic cheeses compared to CC. The amount of conjugated linoleic acid increased in CLA, CBB and CLB. The highest depth of proteolysis and the greatest changes in the release of free amino acids were found in CLB. The addition of inulin and probiotics, alone or in co-culture, did not affect the cheese acceptance. Inulin and probiotics can be used together for the production of creamy goat cheese without negatively affecting the general quality characteristics of the product, and to add value because of its synbiotic potential.

  16. High temperature strain gage apparent strain compensation

    NASA Technical Reports Server (NTRS)

    Holmes, Harlan K.; Moore, T. C., Sr.

    1992-01-01

    Once an installed strain gage is connected to a strain indicating device and the instrument is balanced, a subsequent change in temperature of the gage installation will generally produce a resistance change in the gage. This purely temperature-induced resistance will be registered by the indicating device as a strain and is referred to as 'apparent strain' to distinguish it from strain due to applied stress. One desirable technique for apparent strain compensation is to employ two identical gages with identical mounting procedures which are connected with a 'half bridge' configuration where gages see the same thermal environment but only one experiences a mechanical strain input. Their connection in adjacent arms of the bridge will then balance the thermally induced apparent strains and, in principle, only the mechanical strain remains. Two approaches that implement this technique are discussed.

  17. Systematic review and meta-analysis: Multi-strain probiotics as adjunct therapy for Helicobacter pylori eradication and prevention of adverse events

    PubMed Central

    Huang, Ying; Wang, Lin; Malfertheiner, Peter

    2015-01-01

    Background Eradication rates with triple therapy for Helicobacter pylori infections have currently declined to unacceptable levels worldwide. Newer quadruple therapies are burdened with a high rate of adverse events. Whether multi-strain probiotics can improve eradication rates or diminish adverse events remains uncertain. Methods Relevant publications in which patients with H. pylori infections were randomized to a multi-strain probiotic or control were identified in PubMed, Cochrane Databases, and other sources from 1 January 1960–3 June 2015. Primary outcomes included eradication rates, incidence of any adverse event and the incidence of antibiotic-associated diarrhea. As probiotic efficacy is strain-specific, pooled relative risks and 95% confidence intervals were calculated using meta-analysis stratified by similar multi-strain probiotic mixtures. Results A total of 19 randomized controlled trials (20 treatment arms, n = 2730) assessing one of six mixtures of strains of probiotics were included. Four multi-strain probiotics significantly improved H. pylori eradication rates, five significantly prevented any adverse reactions and three significantly reduced antibiotic-associated diarrhea. Only two probiotic mixtures (Lactobacillus acidophilus/Bifidobacterium animalis and an eight-strain mixture) had significant efficacy for all three outcomes. Conclusions Our meta-analysis found adjunctive use of some multi-strain probiotics may improve H. pylori eradication rates and prevent the development of adverse events and antibiotic-associated diarrhea, but not all mixtures were effective. PMID:27536365

  18. Comparative Analysis of the Effects of Two Probiotic Bacterial Strains on Metabolism and Innate Immunity in the RAW 264.7 Murine Macrophage Cell Line.

    PubMed

    Pradhan, Biswaranjan; Guha, Dipanjan; Ray, Pratikshya; Das, Debashmita; Aich, Palok

    2016-06-01

    Probiotic and potential probiotic bacterial strains are routinely prescribed and used as supplementary therapy for a variety infectious diseases, including enteric disorders among a wide range of individuals. While there are an increasing number of studies defining the possible mechanisms of probiotic activity, a great deal remains unknown regarding the diverse modes of action attributed to these therapeutic agents. More precise information is required to support the appropriate application of probiotics. To address this objective, we selected two probiotics strains, Lactobacillus acidophilus MTCC-10307 (LA) and Bacillus clausii MTCC-8326 (BC) that are frequently prescribed for the treatment of intestinal disorders and investigated their effects on the RAW 264.7 murine macrophage cell line. Our results reveal that LA and BC are potent activators of both metabolic activity and innate immune responses in these cells. We also observed that LA and BC possessed similar activity in preventing infection simulated in vitro in murine macrophages by Salmonella typhimurium serovar enterica.

  19. Geobacteraceae strains and methods

    DOEpatents

    Lovley, Derek R.; Nevin, Kelly P.; Yi, Hana

    2015-07-07

    Embodiments of the present invention provide a method of producing genetically modified strains of electricigenic microbes that are specifically adapted for the production of electrical current in microbial fuel cells, as well as strains produced by such methods and fuel cells using such strains. In preferred embodiments, the present invention provides genetically modified strains of Geobacter sulfurreducens and methods of using such strains.

  20. Safety and Protective Effectiveness of Two Strains of Lactobacillus with Probiotic Features in an Experimental Model of Salmonellosis

    PubMed Central

    Steinberg, Raphael S.; Silva, Lilian C. S.; Souza, Tássia C.; Lima, Maurício T.; de Oliveira, Nayara L. G.; Vieira, Leda Q.; Arantes, Rosa M. E.; Miyoshi, Anderson; Nicoli, Jacques R.; Neumann, Elisabeth; Nunes, Álvaro C.

    2014-01-01

    Two strains of Lactobacillus, previously isolated from bovine faeces and tested in vitro for properties desired in probiotics, were evaluated for their in vivo effectiveness in protecting against experimental salmonellosis. L. salivarius L38 and L. acidophilus L36 previously demonstrated the ability to successfully colonize the gastrointestinal tract of germ-free mice and stimulate the immune system associated with the intestinal mucosa. L38- or L36-feeding showed no detrimental effect on the general health indicators and did not induce changes in normal architecture of liver and small intestine, indicating that the use of these strains is apparently safe. In control animals fed L38 strain, several cytokines had augmented mRNA levels that can be associated with a homeostatic state of intestinal mucosa, while L36 had less diverse regulation. IgA production and secretion in the intestinal lumen induced by infection was abrogated by pretreating with both lactobacilli. In addition, liver and small intestine histological scores and, translocation of Salmonella cells to liver and spleen, indicated that these strains did not confer protection against the infection. So, the IL-12:IL-18➔IFN-γ axis, essential for an effective immune response against Salmonella, was not favored with L38 or L36 strains. However, increased expression of IL-10 in different portions of the gastrointestinal tract of L38-fed animals is indicative of anti-inflammatory effect to be explored furthermore. PMID:25162711

  1. Sulfobacillus thermosulfidooxidans strain Cutipay enhances chalcopyrite bioleaching under moderate thermophilic conditions in the presence of chloride ion.

    PubMed

    Bobadilla-Fazzini, Roberto A; Cortés, Maria Paz; Maass, Alejandro; Parada, Pilar

    2014-12-01

    Currently more than 90% of the world's copper is obtained through sulfide mineral processing. Among the copper sulfides, chalcopyrite is the most abundant and therefore economically relevant. However, primary copper sulfide bioleaching is restricted due to high ionic strength raffinate solutions and particularly chloride coming from the dissolution of ores. In this work we describe the chalcopyrite bioleaching capacity of Sulfobacillus thermosulfidooxidans strain Cutipay (DSM 27601) previously described at the genomic level (Travisany et al. (2012) Draft genome sequence of the Sulfobacillus thermosulfidooxidans Cutipay strain, an indigenous bacterium isolated from a naturally extreme mining environment in Northern Chile. J Bacteriol 194:6327-6328). Bioleaching assays with the mixotrophic strain Cutipay showed a strong increase in copper recovery from chalcopyrite concentrate at 50°C in the presence of chloride ion, a relevant inhibitory element present in copper bioleaching processes. Compared to the abiotic control and a test with Sulfobacillus acidophilus DSM 10332, strain Cutipay showed an increase of 42 and 69% in copper recovery, respectively, demonstrating its high potential for chalcopyrite bioleaching. Moreover, a genomic comparison highlights the presence of the 2-Haloacid dehalogenase predicted-protein related to a potential new mechanism of chloride resistance in acidophiles. This novel and industrially applicable strain is under patent application CL 2013-03335.

  2. Antibiotic resistance and molecular characterization of probiotic and clinical Lactobacillus strains in relation to safety aspects of probiotics.

    PubMed

    Klein, Günter

    2011-02-01

    The evaluation of the safety of probiotic strains includes the exclusion of antibiotic resistance of clinical importance. Ninety-two strains from the genus Lactobacillus isolated from probiotics, food, and clinical sources were included in the investigation. Species tested were the L. acidophilus group, L. casei group, L. reuteri/fermentum group, and L. sakei/curvatus group. Cell and colony morphology, fermentation patterns, and growth characteristics as well as soluble whole cell proteins were analyzed. Antibiotic resistance against clinically important agents was determined by broth dilution tests. The vanA and tet genes were confirmed. Resistances occurred mainly against gentamicin, ciprofloxacin, clindamycin, sulfonamides, and, in some cases, glycopeptides. The natural glycopeptide resistance within the L. casei group and L. reuteri appears to be not of clinical relevance, as there was no vanA gene present. Therefore, the transfer of this resistance is very unlikely. Tet-(A), -(B), -(C), -(M), or -(O) gene could not be detected. The protein fingerprinting within the L. casei group proved that L. rhamnosus strains of clinical origin clustered together with probiotic strains. For safety evaluations resistance patterns of a broad range of strains are a useful criterion together with the exclusion of known resistance genes (like the vanA gene) and can be used for decision making on the safety of probiotics, both by authorization bodies and manufacturers.

  3. Safety and protective effectiveness of two strains of Lactobacillus with probiotic features in an experimental model of salmonellosis.

    PubMed

    Steinberg, Raphael S; Silva, Lilian C S; Souza, Tássia C; Lima, Maurício T; de Oliveira, Nayara L G; Vieira, Leda Q; Arantes, Rosa M E; Miyoshi, Anderson; Nicoli, Jacques R; Neumann, Elisabeth; Nunes, Alvaro C

    2014-08-26

    Two strains of Lactobacillus, previously isolated from bovine faeces and tested in vitro for properties desired in probiotics, were evaluated for their in vivo effectiveness in protecting against experimental salmonellosis. L. salivarius L38 and L. acidophilus L36 previously demonstrated the ability to successfully colonize the gastrointestinal tract of germ-free mice and stimulate the immune system associated with the intestinal mucosa. L38- or L36-feeding showed no detrimental effect on the general health indicators and did not induce changes in normal architecture of liver and small intestine, indicating that the use of these strains is apparently safe. In control animals fed L38 strain, several cytokines had augmented mRNA levels that can be associated with a homeostatic state of intestinal mucosa, while L36 had less diverse regulation. IgA production and secretion in the intestinal lumen induced by infection was abrogated by pretreating with both lactobacilli. In addition, liver and small intestine histological scores and, translocation of Salmonella cells to liver and spleen, indicated that these strains did not confer protection against the infection. So, the IL-12:IL-18àIFN-g axis, essential for an effective immune response against Salmonella, was not favored with L38 or L36 strains. However, increased expression of IL-10 in different portions of the gastrointestinal tract of L38-fed animals is indicative of anti-inflammatory effect to be explored furthermore.

  4. Muscle strain treatment

    MedlinePlus

    Treatment - muscle strain ... Question: How do you treat a muscle strain ? Answer: Rest the strained muscle and apply ice for the first few days after the injury. Anti-inflammatory medicines or acetaminophen ( ...

  5. Muscle strain (image)

    MedlinePlus

    A muscle strain is the stretching or tearing of muscle fibers. A muscle strain can be caused by sports, exercise, a ... something that is too heavy. Symptoms of a muscle strain include pain, tightness, swelling, tenderness, and the ...

  6. In vitro fermentation of rice bran combined with Lactobacillus acidophilus 14 150B or Bifidobacterium longum 05 by the canine faecal microbiota.

    PubMed

    Ogué-Bon, Eva; Khoo, Christina; Hoyles, Lesley; McCartney, Anne L; Gibson, Glenn R; Rastall, Robert A

    2011-03-01

    The fermentability of rice bran (RB), alone or in combination with one of two probiotics, by canine faecal microbiota was evaluated in stirred, pH-controlled, anaerobic batch cultures. RB enhanced the levels of bacteria detected by probes Bif164 (bifidobacteria) and Lab158 (lactic acid bacteria); however, addition of the probiotics did not have a significant effect on the predominant microbial counts compared with RB alone. RB sustained levels of Bifidobacterium longum 05 throughout the fermentation; in contrast, Lactobacillus acidophilus 14 150B levels decreased significantly after 5-h fermentation. RB fermentation induced changes in the short-chain fatty acid (SCFA) profile. However, RB combined with probiotics did not alter the SCFA levels compared with RB alone. Denaturing gradient gel electrophoresis analysis of samples obtained at 24 h showed a treatment effect with RB, which was not observed in the RB plus probiotic systems. Overall, the negative controls displayed lower species richness than the treatment systems and their banding profiles were distinct. This study illustrates the ability of a common ingredient found in pet food to modulate the canine faecal microbiota and highlights that RB may be an economical alternative to prebiotics for use in dog food.

  7. Unveiling of novel regio-selective fatty acid double bond hydratases from Lactobacillus acidophilus involved in the selective oxyfunctionalization of mono- and di-hydroxy fatty acids.

    PubMed

    Kim, Kyoung-Rok; Oh, Hye-Jin; Park, Chul-Soon; Hong, Seung-Hye; Park, Ji-Young; Oh, Deok-Kun

    2015-11-01

    The aim of this study is the first time demonstration of cis-12 regio-selective linoleate double-bond hydratase. Hydroxylation of fatty acids, abundant feedstock in nature, is an emerging alternative route for many petroleum replaceable products thorough hydroxy fatty acids, carboxylic acids, and lactones. However, chemical route for selective hydroxylation is still quite challenging owing to low selectivity and many environmental concerns. Hydroxylation of fatty acids by hydroxy fatty acid forming enzymes is an important route for selective biocatalytic oxyfunctionalization of fatty acids. Therefore, novel fatty acid hydroxylation enzymes should be discovered. The two hydratase genes of Lactobacillus acidophilus were identified by genomic analysis, and the expressed two recombinant hydratases were identified as cis-9 and cis-12 double-bond selective linoleate hydratases by in vitro functional validation, including the identification of products and the determination of regio-selectivity, substrate specificity, and kinetic parameters. The two different linoleate hydratases were the involved enzymes in the 10,13-dihydroxyoctadecanoic acid biosynthesis. Linoleate 13-hydratase (LHT-13) selectively converted 10 mM linoleic acid to 13S-hydroxy-9(Z)-octadecenoic acid with high titer (8.1 mM) and yield (81%). Our study will expand knowledge for microbial fatty acid-hydroxylation enzymes and facilitate the designed production of the regio-selective hydroxy fatty acids for useful chemicals from polyunsaturated fatty acid feedstocks.

  8. Cell growth and proteolytic activity of Lactobacillus acidophilus, Lactobacillus helveticus, Lactobacillus delbrueckii ssp. bulgaricus, and Streptococcus thermophilus in milk as affected by supplementation with peptide fractions.

    PubMed

    Gandhi, Akanksha; Shah, Nagendra P

    2014-12-01

    The present investigation examined the effects of supplementation of milk peptide fractions produced by enzymatic hydrolysis on the fermentation of reconstituted skim milk (RSM). Changes in pH, cell growth, proteolytic activity, and angiotensin-converting enzyme (ACE)-inhibitory activity were monitored during fermentation of RSM by pure cultures of Lactobacillus acidophilus, Lactobacillus helveticus, Lactobacillus delbrueckii ssp. bulgaricus, and Streptococcus thermophilus. The study showed that supplementation with peptide fractions of different molecular weights did not significantly affect the bacterial growth in RSM. All bacteria showed an increased proteolytic activity in RSM supplemented with large peptides (>10 kDa), and L. helveticus in general exhibited the highest proteolytic activity among the bacteria studied. The ACE-inhibitory activity was observed to be the maximum in RSM supplemented with larger peptides (>10 kDa) for all bacteria. The results suggest that proteolysis by bacteria leads to increased production of ACE-inhibitory peptides compared to the supplemented peptides produced by enzymatic hydrolysis.

  9. Inhibition of H9N2 Virus Invasion into Dendritic Cells by the S-Layer Protein from L. acidophilus ATCC 4356.

    PubMed

    Gao, Xue; Huang, Lulu; Zhu, Liqi; Mou, Chunxiao; Hou, Qihang; Yu, Qinghua

    2016-01-01

    Probiotics are essential for the prevention of virus invasion and the maintenance of the immune balance. However, the mechanism of competition between probiotics and virus are unknown. The objectives of this study were to isolate the surface layer (S-layer) protein from L. acidophilus ATCC 4356 as a new antiviral material, to evaluate the stimulatory effects of the S-layer protein on mouse dendritic cells (DCs) and to verify its ability to inhibit the invasion of H9N2 avian influenza virus (AIV) in DCs. We found that the S-layer protein induced DCs activation and up-regulated the IL-10 secretion. The invasion and replication of the H9N2 virus in mouse DCs was successfully demonstrated. However, the invasion of H9N2 virus into DCs could be inhibited by treatment with the S-layer protein prior to infection, which was verified by the reduced hemagglutinin (HA) and neuraminidase (NA) mRNA expression, and nucleoprotein (NP) protein expression in the DCs. Furthermore, treatment with the S-layer protein increases the Mx1, Isg15, and Ddx58 mRNA expressions, and remits the inflammatory process to inhibit H9N2 AIV infection. In conclusion, the S-layer protein stimulates the activation of mouse DCs, inhibits H9N2 virus invasion of DCs, and stimulates the IFN-I signaling pathway. Thus, the S-layer protein from Lactobacillus is a promising biological antiviral material for AIV prevention.

  10. Early administration of probiotic Lactobacillus acidophilus and/or prebiotic inulin attenuates pathogen-mediated intestinal inflammation and Smad 7 cell signaling.

    PubMed

    Foye, Ondulla T; Huang, I-Fei; Chiou, Christine C; Walker, W Allan; Shi, Hai Ning

    2012-08-01

    Immaturity of gut-associated immunity may contribute to pediatric mortality associated with enteric infections. A murine model to parallel infantile enteric disease was used to determine the effects of probiotic, Lactobacillus acidophilus (La), prebiotic, inulin, or both (synbiotic, syn) on pathogen-induced inflammatory responses, NF-κB, and Smad 7 signaling. Newborn mice were inoculated bi-weekly for 4 weeks with La, inulin, or syn and challenged with Citrobacter rodentium (Cr) at 5 weeks. Mouse intestinal epithelial cells (CMT93) were exposed to Cr to determine temporal alterations in NF-Kappa B and Smad 7 levels. Mice with pretreatment of La, inulin, and syn show reduced intestinal inflammation following Cr infection compared with controls, which is associated with significantly reduced bacterial colonization in La, inulin, and syn animals. Our results further show that host defense against Cr infection correlated with enhanced colonic IL-10 and transforming growth factor-β expression and inhibition of NF-κB in syn-treated mice, whereas mice pretreated with syn, La, or inulin had attenuation of Cr-induced Smad 7 expression. There was a temporal Smad 7 and NF-κB intracellular accumulation post-Cr infection and post-tumor necrosis factor stimulation in CMT93 cells. These results, therefore, suggest that probiotic, La, prebiotic inulin, or synbiotic may promote host-protective immunity and attenuate Cr-induced intestinal inflammation through mechanisms affecting NF-κB and Smad 7 signaling.

  11. The Differential Proteome of the Probiotic Lactobacillus acidophilus NCFM Grown on the Potential Prebiotic Cellobiose Shows Upregulation of Two β -Glycoside Hydrolases.

    PubMed

    van Zanten, Gabriella C; Sparding, Nadja; Majumder, Avishek; Lahtinen, Sampo J; Svensson, Birte; Jacobsen, Susanne

    2015-01-01

    Probiotics, prebiotics, and combinations thereof, that is, synbiotics, are known to exert beneficial health effects in humans; however interactions between pro- and prebiotics remain poorly understood at the molecular level. The present study describes changes in abundance of different proteins of the probiotic bacterium Lactobacillus acidophilus NCFM (NCFM) when grown on the potential prebiotic cellobiose as compared to glucose. Cytosolic cell extract proteomes after harvest at late exponential phase of NCFM grown on cellobiose or glucose were analyzed by two dimensional difference gel electrophoresis (2D-DIGE) in the acidic (pH 4-7) and the alkaline (pH 6-11) regions showing a total of 136 spots to change in abundance. Proteins were identified by MS or MS/MS from 81 of these spots representing 49 unique proteins and either increasing 1.5-13.9-fold or decreasing 1.5-7.8-fold in relative abundance. Many of these proteins were associated with energy metabolism, including the cellobiose related glycoside hydrolases phospho-β-glucosidase (LBA0881) and phospho-β-galactosidase II (LBA0726). The data provide insight into the utilization of the candidate prebiotic cellobiose by the probiotic bacterium NCFM. Several of the upregulated or downregulated identified proteins associated with utilization of cellobiose indicate the presence of carbon catabolite repression and regulation of enzymes involved in carbohydrate metabolism.

  12. Inhibition of H9N2 Virus Invasion into Dendritic Cells by the S-Layer Protein from L. acidophilus ATCC 4356

    PubMed Central

    Gao, Xue; Huang, Lulu; Zhu, Liqi; Mou, Chunxiao; Hou, Qihang; Yu, Qinghua

    2016-01-01

    Probiotics are essential for the prevention of virus invasion and the maintenance of the immune balance. However, the mechanism of competition between probiotics and virus are unknown. The objectives of this study were to isolate the surface layer (S-layer) protein from L. acidophilus ATCC 4356 as a new antiviral material, to evaluate the stimulatory effects of the S-layer protein on mouse dendritic cells (DCs) and to verify its ability to inhibit the invasion of H9N2 avian influenza virus (AIV) in DCs. We found that the S-layer protein induced DCs activation and up-regulated the IL-10 secretion. The invasion and replication of the H9N2 virus in mouse DCs was successfully demonstrated. However, the invasion of H9N2 virus into DCs could be inhibited by treatment with the S-layer protein prior to infection, which was verified by the reduced hemagglutinin (HA) and neuraminidase (NA) mRNA expression, and nucleoprotein (NP) protein expression in the DCs. Furthermore, treatment with the S-layer protein increases the Mx1, Isg15, and Ddx58 mRNA expressions, and remits the inflammatory process to inhibit H9N2 AIV infection. In conclusion, the S-layer protein stimulates the activation of mouse DCs, inhibits H9N2 virus invasion of DCs, and stimulates the IFN-I signaling pathway. Thus, the S-layer protein from Lactobacillus is a promising biological antiviral material for AIV prevention. PMID:27826541

  13. Superlattice strain gage

    DOEpatents

    Noel, B.W.; Smith, D.L.; Sinha, D.N.

    1988-06-28

    A strain gage comprising a strained-layer superlattice crystal exhibiting piezoelectric properties is described. A substrate upon which such a strained-layer superlattice crystal has been deposited is attached to an element to be monitored for strain. A light source is focused on the superlattice crystal and the light reflected from, passed through, or emitted from the crystal is gathered and compared with previously obtained optical property data to determine the strain in the element. 8 figs.

  14. Superlattice strain gage

    DOEpatents

    Noel, Bruce W.; Smith, Darryl L.; Sinha, Dipen N.

    1990-01-01

    A strain gage comprising a strained-layer superlattice crystal exhibiting piezoelectric properties is described. A substrate upon which such a strained-layer superlattice crystal has been deposited is attached to an element to be monitored for strain. A light source is focused on the superlattice crystal and the light reflected from, passed through, or emitted from the crystal is gathered and compared with previously obtained optical property data to determine the strain in the element.

  15. Evaluation of probiotic strains for development of fermented Alisma canaliculatum and their effects on broiler chickens.

    PubMed

    Hossain, M E; Ko, S Y; Kim, G M; Firman, J D; Yang, C J

    2012-12-01

    The present study was conducted to select appropriate microbial strains for the development of fermented Alisma canaliculatum A. Br. et Bouche (FAC) feed additive and to examine their effects on broilers. In experiment 1, 16 strains of Lactobacillus acidophilus, Lactobacillus plantarum, Enterococcus faecium, Bacillus subtilis, Bacillus coagulans, and Saccharomyces cerevisiae from the Korean Collection for Type Cultures (KCTC) were evaluated. The strains were tested for their acid, bile, and heat tolerance levels. Among them, L. acidophilus KCTC 3111, E. faecium KCTC 2022, B. subtilis KCTC 3239, and S. cerevisiae KCTC 7928 were selected to produce FAC. For experiment 2, 140 Ross broiler chicks were allocated to four 5-wk-long dietary groups: NC (basal diet), PC (basal diet with 0.005% oxytetracycline), AC (basal diet with 0.5% A. canaliculatum rhizome powder), and FAC (basal diet with 0.5% FAC). Final BW and total BW gain were increased (P < 0.05) upon the addition of FAC, whereas feed conversion ratio improved (P < 0.05) in the supplemented groups compared with the NC group. Crude protein content increased and crude fat decreased (P < 0.05) in the breast meat of the FAC group compared with the AC and PC groups, respectively. Proventriculus and kidney relative weights of the FAC group differed (P < 0.05) from the AC group but not from the PC group. Lower (P < 0.05) thiobarbituric acid reactive substances value of thigh meat was observed in the FAC group compared with the other groups. The FAC diet increased (P < 0.05) α-linolenic acid and linoleic acid in meat. Alteration of these fatty acids led to increased levels of polyunsaturated fatty acid, polyunsaturated fatty acid /saturated fatty acid, n-3 and n-6 fatty acids, and decreased n-6/n-3 ratio in breast or thigh meat (P < 0.05). It is concluded that FAC confers high tolerance to acid, bile and heat; and beneficially affects growth, meat composition, oxidative stability, and fatty acid composition. The FAC may

  16. Live encapsulated Lactobacillus acidophilus cells in yogurt for therapeutic oral delivery: preparation and in vitro analysis of alginate-chitosan microcapsules.

    PubMed

    Urbanska, Aleksandra Malgorzata; Bhathena, Jasmine; Prakash, Satya

    2007-09-01

    Targeted delivery of live microencapsulated bacterial cells has strong potential for application in treating various diseases, including diarrhea, kidney failure, liver failure, and high cholesterol, among others. This study investigates the potential of microcapsules composed of two natural polymers, alginate and chitosan (AC), and the use of these artificial cells in yogurt for delivery of probiotic Lactobacillus acidophilus bacterial live cells. Results show that the integrity of AC microcapsules was preserved after 76 h of mechanical shaking in MRS broth and after 12 h and 24 h in simulated gastric and intestinal fluids. Using an in vitro computer-controlled simulated human gastrointestinal (GI) model, we found 8.37 log CFU/mL of viable bacterial cells were present after 120 min of gastric exposure and 7.96 log CFU/mL after 360 min of intestinal exposure. In addition, AC microcapsules composed of chitosan 10 and 100 at various concentrations were subjected to 4-week storage in 2% milk fat yogurt or 0.85% physiological solution. It was found that 9.37 log CFU/mL of cells encapsulated with chitosan 10 and 8.24 log CFU/mL of cells encapsulated with chitosan 100 were alive after 4 weeks. The AC capsule composed of 0.5% chitosan 10 provided the highest bacterial survival of 9.11 log CFU/mL after 4 weeks. Finally, an investigation of bacterial viability over 72 h in different pH buffers yielded highest survival of 6.34 log CFU/mL and 10.34 log CFU/mL at pH 8 for free and AC-encapsulated cells, respectively. We conclude from these findings that encapsulation allows delivery of a higher number of bacteria to desired targets in the GI tract and that microcapsules containing bacterial cells are good candidates for oral artificial cells for bacterial cell therapy.

  17. Quantitative profiling of bacteriocins present in dairy-free probiotic preparations of Lactobacillus acidophilus by nanoliquid chromatography-tandem mass spectrometry.

    PubMed

    Nandakumar, Renu; Talapatra, Kesh

    2014-01-01

    Bacteriocins are a heterogeneous group of ribosomally synthesized peptides or proteins with antimicrobial activity, produced predominantly by lactic acid bacteria, with potential applications as biopreservatives and probiotics. We describe here a novel strategy based on a bottom-up, shotgun proteomic approach using nanoliquid chromatography-tandem mass spectrometry (nanoLC-MS/MS) with multiple fragmentation techniques for the quantitative profiling of bacteriocins present in the probiotic preparations of Lactobacillus acidophilus. A direct LC-MS/MS analysis with alternate collision-induced dissociation, high-energy collision dissociation, and electron-transfer dissociation fragmentation following a filter-assisted size-exclusion sample prefractionation has resulted in the identification of peptides belonging to 37 bacteriocins or related proteins. Peptides from lactacin F, helveticin J, lysin, avicin A, acidocin M, curvaticin FS47, and carocin D were predominant. The process of freeze drying under vacuum was observed to affect both the diversity and abundance of bacteriocins. Data acquisition using alternating complementary peptide fragmentation modes, especially electron-transfer dissociation, has significantly enhanced the peptide sequence coverage and number of bacteriocin peptides identified. Multi-enzyme proteolytic digestion was observed to increase the sample complexity and dynamic range, lowering the chances of detection of low-abundant bacteriocin peptides by LC-MS/MS. An analytical platform integrating size exclusion prefractionation, nanoLC-MS/MS analysis with multiple fragmentation techniques, and data-dependent decision tree-driven bioinformatic data analysis is novel in bacteriocin research and suitable for the comprehensive bioanalysis of diverse, low-abundant bacteriocins in complex samples.

  18. Design and validation of an orally administrated active L. fermentum-L. acidophilus probiotic formulation using colorectal cancer Apc (Min/+) mouse model.

    PubMed

    Kahouli, Imen; Malhotra, Meenakshi; Westfall, Susan; Alaoui-Jamali, Moulay A; Prakash, Satya

    2017-03-01

    Probiotics have been shown to have beneficial properties in attenuating the risk of colorectal cancer (CRC) development. However, functional evidence to support such effects for some probiotic bacteria are relatively unknown. Here, we document a significant antioxidant, anti-proliferative and pro-apoptotic activities of Lactobacillus acidophilus ATCC 314 and Lactobacillus fermentum NCIMB 5221 on CRC cells, particularly when used in combination (La-Lf). Furthermore, a superior synergistic activity on the inhibition of tumor growth and modulation of cell proliferation and epithelial markers in the Apc (Min/+) CRC mouse model was explored, based on the expression levels of Ki-67, E-cadherin, β-catenin, and cleaved caspase-3 (CC3) proteins. The anti-cancer activity of La-Lf co-culture was significantly enhanced in vitro with significant reduced proliferation (38.8 ± 6.9 %, P = 0.009) and increased apoptosis (413 RUL, P < 0.001) towards cancer cells, as well as significant protection of normal colon cell growth from toxic treatment (18.6 ± 9.8 %, P = 0.001). La-Lf formulation (10(10)cfu/animal/day) altered aspects of intestinal tumorigenesis by significantly reducing intestinal tumor multiplicity (1.7-fold, P = 0.016) and downregulating cellular proliferation markers, including β-catenin (P = 0.041) and Ki-67 (P = 0.008). In conclusion, La-Lf showed greater protection against intestinal tumorigenesis supporting a potential use as a biotherapeutic for the prevention of CRC.

  19. Elevated temperature strain gages

    NASA Technical Reports Server (NTRS)

    Brittain, J. O.; Geslin, D.; Lei, J. F.

    1985-01-01

    Materials were evaluated that could be used in manufacturing electrical resistance strain gages for static strain measurements at temperatures at or above 1273 K. Strain gage materials must have a characteristic response to strain, temperature and time that is reproducible or that varies in a predictable manner within specified limits. Several metallic alloys were evaluated, as well as a series of transition metal carbides, nitrides and silicides.

  20. Sprains and Strains

    MedlinePlus

    ... happens. A strain is a stretched or torn muscle or tendon. Tendons are tissues that connect muscle to bone. Twisting or pulling these tissues can ... suddenly or develop over time. Back and hamstring muscle strains are common. Many people get strains playing ...

  1. Strain powered antennas

    NASA Astrophysics Data System (ADS)

    Domann, John P.; Carman, Greg P.

    2017-01-01

    This paper proposes the creation of strain powered antennas that radiate electromagnetic energy by mechanically vibrating a piezoelectric or piezomagnetic material. A closed form analytic model of electromagnetic radiation from a strain powered electrically small antenna is derived and analyzed. Fundamental scaling laws and the frequency dependence of strain powered antennas are discussed. The radiation efficiency of strain powered electrically small antennas is contrasted with a conventional electric dipole. Analytical results show that operating at the first mechanical resonance produces the most efficient strain powered radiation relative to electric dipole antennas. A resonant analysis is exploited to determine the material property space that produces efficient strain powered antennas. These results show how a properly designed strain powered antenna can radiate more efficiently than an equally sized electric dipole antenna.

  2. Comparison of adhesive gut bacteria composition, immunity, and disease resistance in juvenile hybrid tilapia fed two different Lactobacillus strains.

    PubMed

    Liu, Wenshu; Ren, Pengfei; He, Suxu; Xu, Li; Yang, Yaling; Gu, Zemao; Zhou, Zhigang

    2013-07-01

    This study compares the effects of two Lactobacillus strains, highly adhesive Lactobacillus brevis JCM 1170 (HALB) and less-adhesive Lactobacillus acidophilus JCM 1132 (LALB), on the survival and growth, adhesive gut bacterial communities, immunity, and protection against pathogenic bacterial infection in juvenile hybrid tilapia. During a 5-week feeding trial the fish were fed a diet containing 0 to 10(9) cells/g feed of the two Lactobacillus strains. Samples of intestine, kidney, and spleen were taken at the start and at 10, 20, and 35 days for analysis of stress tolerance and cytokine gene mRNA levels and to assess the diversity of adhesive gut bacterial communities. A 14-day immersion challenge with Aeromonas hydrophila NJ-1 was also performed following the feeding trial. The results showed no significant differences in survival rate, weight gain, or feed conversion in the different dietary treatments. The adhesive gut bacterial communities were strikingly altered in the fish fed either the HALB or the LALB, but the response was more rapid and substantial with the adhesive strain. The two strains induced similar changes in the patterns (upregulation or downregulation) of intestinal, splenic or kidney cytokine expression, but they differed in the degree of response for these genes. Changes in intestinal HSP70 expression levels coincided with changes in the similarity coefficient of the adhesive gut bacterial communities between the probiotic treatments. The highest dose of the HALB appeared to protect against the toxic effects of immersion in A. hydrophila (P < 0.05). In conclusion, the degree to which Lactobacillus strains adhere to the gut may be a favorable criterion in selecting probiotic strain for aquaculture.

  3. The maltodextrin transport system and metabolism in Lactobacillus acidophilus NCFM and production of novel alpha-glucosides through reverse phosphorolysis by maltose phosphorylase.

    PubMed

    Nakai, Hiroyuki; Baumann, Martin J; Petersen, Bent O; Westphal, Yvonne; Schols, Henk; Dilokpimol, Adiphol; Hachem, Maher A; Lahtinen, Sampo J; Duus, Jens Ø; Svensson, Birte

    2009-12-01

    A gene cluster involved in maltodextrin transport and metabolism was identified in the genome of Lactobacillus acidophilus NCFM, which encoded a maltodextrin-binding protein, three maltodextrin ATP-binding cassette transporters and five glycosidases, all under the control of a transcriptional regulator of the LacI-GalR family. Enzymatic properties are described for recombinant maltose phosphorylase (MalP) of glycoside hydrolase family 65 (GH65), which is encoded by malP (GenBank: AAV43670.1) of this gene cluster and produced in Escherichia coli. MalP catalyses phosphorolysis of maltose with inversion of the anomeric configuration releasing beta-glucose 1-phosphate (beta-Glc 1-P) and glucose. The broad specificity of the aglycone binding site was demonstrated by products formed in reverse phosphorolysis using various carbohydrate acceptor substrates and beta-Glc 1-P as the donor. MalP showed strong preference for monosaccharide acceptors with equatorial 3-OH and 4-OH, such as glucose and mannose, and also reacted with 2-deoxy glucosamine and 2-deoxy N-acetyl glucosamine. By contrast, none of the tested di- and trisaccharides served as acceptors. Disaccharide yields obtained from 50 mmbeta-Glc 1-P and 50 mm glucose, glucosamine, N-acetyl glucosamine, mannose, xylose or l-fucose were 99, 80, 53, 93, 81 and 13%, respectively. Product structures were determined by NMR and ESI-MS to be alpha-Glcp-(1-->4)-Glcp (maltose), alpha-Glcp-(1-->4)-GlcNp (maltosamine), alpha-Glcp-(1-->4)-GlcNAcp (N-acetyl maltosamine), alpha-Glcp-(1-->4)-Manp, alpha-Glcp-(1-->4)-Xylp and alpha-Glcp-(1-->4)- L-Fucp, the three latter being novel compounds. Modelling using L. brevis GH65 as the template and superimposition of acarbose from a complex with Thermoanaerobacterium thermosaccharolyticum GH15 glucoamylase suggested that loop 3 of MalP involved in substrate recognition blocked the binding of candidate acceptors larger than monosaccharides.

  4. Three dimensional strained semiconductors

    DOEpatents

    Voss, Lars; Conway, Adam; Nikolic, Rebecca J.; Leao, Cedric Rocha; Shao, Qinghui

    2016-11-08

    In one embodiment, an apparatus includes a three dimensional structure comprising a semiconductor material, and at least one thin film in contact with at least one exterior surface of the three dimensional structure for inducing a strain in the structure, the thin film being characterized as providing at least one of: an induced strain of at least 0.05%, and an induced strain in at least 5% of a volume of the three dimensional structure. In another embodiment, a method includes forming a three dimensional structure comprising a semiconductor material, and depositing at least one thin film on at least one surface of the three dimensional structure for inducing a strain in the structure, the thin film being characterized as providing at least one of: an induced strain of at least 0.05%, and an induced strain in at least 5% of a volume of the structure.

  5. Strain sensor comprising a strain sensitive, two-mode optical

    NASA Technical Reports Server (NTRS)

    Egalon, Claudio Oliveira (Inventor); Rogowski, Robert S. (Inventor)

    1994-01-01

    A strain sensor uses an optical fiber including a strain sensitive portion and at least one strain insensitive portion. The strain sensitive portion is mounted on the surface of a structure at a location where a strain is desired to be measured. The strain insensitive portion(s) may be fused to the strain sensitive portion to transmit light therethrough, so that the resulting pattern may be detected to determine the amount of strain by comparison with a similar fiber not subjected to strain, or with the light pattern produced when the fiber is not under strain.

  6. Thin film strain transducer

    NASA Technical Reports Server (NTRS)

    Rand, J. L. (Inventor)

    1984-01-01

    A strain transducer system and process for making the same is disclosed. A beryllium copper ring having four strain gages is electrically connected in Wheatstone bridge fashion to the output instrumentation. Tabs are bonded to a balloon or like surface with strain on the surface causing bending of a ring which provides an electrical signal through the gages proportional to the surface strain. A photographic pattern of a one half ring segment as placed on a sheet of beryllium copper for chem-mill etch formation is illustrated.

  7. Anti-Infective Activities of Lactobacillus Strains in the Human Intestinal Microbiota: from Probiotics to Gastrointestinal Anti-Infectious Biotherapeutic Agents

    PubMed Central

    Liévin-Le Moal, Vanessa

    2014-01-01

    SUMMARY A vast and diverse array of microbial species displaying great phylogenic, genomic, and metabolic diversity have colonized the gastrointestinal tract. Resident microbes play a beneficial role by regulating the intestinal immune system, stimulating the maturation of host tissues, and playing a variety of roles in nutrition and in host resistance to gastric and enteric bacterial pathogens. The mechanisms by which the resident microbial species combat gastrointestinal pathogens are complex and include competitive metabolic interactions and the production of antimicrobial molecules. The human intestinal microbiota is a source from which Lactobacillus probiotic strains have often been isolated. Only six probiotic Lactobacillus strains isolated from human intestinal microbiota, i.e., L. rhamnosus GG, L. casei Shirota YIT9029, L. casei DN-114 001, L. johnsonii NCC 533, L. acidophilus LB, and L. reuteri DSM 17938, have been well characterized with regard to their potential antimicrobial effects against the major gastric and enteric bacterial pathogens and rotavirus. In this review, we describe the current knowledge concerning the experimental antibacterial activities, including antibiotic-like and cell-regulating activities, and therapeutic effects demonstrated in well-conducted, placebo-controlled, randomized clinical trials of these probiotic Lactobacillus strains. What is known about the antimicrobial activities supported by the molecules secreted by such probiotic Lactobacillus strains suggests that they constitute a promising new source for the development of innovative anti-infectious agents that act luminally and intracellularly in the gastrointestinal tract. PMID:24696432

  8. Mechanical strain isolator mount

    NASA Technical Reports Server (NTRS)

    James, Gordon E. (Inventor)

    1991-01-01

    Certain devices such as optical instruments must preserve their alignmental integrity while being subjected to mechanical strain. A mechanical strain isolator mount is provided to preserve the alignmental integrity of an alignment sensitive instrument. An alignment sensitive instrument is mounted on a rectangular base. Flexural legs are connected at their proximal ends to the rectangular base. Flexural legs are also spaced parallel to the sides. Mounting pads are connected to the legs at the distal end and the mechanical strain isolator mount is attached to the substrate by means of threaded bolts. When a mounting pad and its respective leg is subjected to lateral strain in either the X or Y direction via the substrate, the respective leg relieves the strain by bending in the direction of the strain. An axial strain on a mounting pad in the Z direction is relieved by a rotational motion of the legs in the direction of the strain. When the substrate is stress free, the flexural legs return to their original condition and thus preserve the original alignment integrity of the alignment sensitive instrument.

  9. Light intensity strain analysis

    NASA Technical Reports Server (NTRS)

    Williams, J. G. (Inventor)

    1973-01-01

    A process is described for the analysis of the strain field of structures subjected to large deformations involving a low modulus substrate having a high modulus, relatively thin coating. The optical properties of transmittance and reflectance are measured for the coated substrate while stressed and unstressed to indicate the strain field for the coated substrate.

  10. Probiotic and cultural characteristic of strain Lactobacillus gasseri 4/13 of human origin.

    PubMed

    Baltova, Kalinka; Dimitrov, Zhechko

    2014-11-02

    Lactobacillus gasseri within the Lactobacillus acidophilus group is a major species in the human microflora. The potential probiotic properties of a L. gasseri strain of human origin were evaluated. Out of 17 studied L. gasseri strains, L. gasseri 4/13 showed the highest immunomodulatory effect (induction of interferon gamma measured by sandwich enzyme-linked immunosorbent assay) in Balb/c mouse splenocytes in vitro and the highest rate of adhesion to Caco-2 human epithelial cells. The strain also reduced the concentration of cholesterol in the growth medium by 65% as compared with the initial concentration (measured spectrophotometrically). These probiotic properties indicate that L. gasseri 4/13 could prove an attractive concentrated adjunct monoculture in the production of new functional foods. To obtain a freeze-dried bacterial concentrate from L. gasseri 4/13, the influence of different culture media, temperatures and pH values on the accumulation of cell biomass was studied. Yoghurt samples were produced using a classical fermentation technology. Freeze-dried concentrated monoculture of L. gasseri 4/13 with over 1 × 10(10) CFU/g viable cells was added as an adjunct culture together with a starter. The viable L. gasseri 4/13 cells remained above the critical value of 10(6) CFU/g during storage at 5 °C for the entire 20-day period. Organoleptic tests did not reveal any adverse change in the product taste and aroma of yoghurt samples at the 20th day. In conclusion, L. gasseri 4/13 was selected as having suitable probiotic and cultural characteristics for production of fermented milk products with high nutritional and biological value.

  11. Protective Effect of Dual-Strain Probiotics in Preterm Infants: A Multi-Center Time Series Analysis

    PubMed Central

    Schwab, Frank; Garten, Lars; Geffers, Christine; Gastmeier, Petra; Piening, Brar

    2016-01-01

    Objective To determine the effect of dual-strain probiotics on the development of necrotizing enterocolitis (NEC), mortality and nosocomial bloodstream infections (BSI) in preterm infants in German neonatal intensive care units (NICUs). Design A multi-center interrupted time series analysis. Setting 44 German NICUs with routine use of dual-strain probiotics on neonatal ward level. Patients Preterm infants documented by NEO-KISS, the German surveillance system for nosocomial infections in preterm infants with birth weights below 1,500 g, between 2004 and 2014. Intervention Routine use of dual-strain probiotics containing Lactobacillus acidophilus and Bifidobacterium spp. (Infloran) on the neonatal ward level. Main outcome measures Incidences of NEC, overall mortality, mortality following NEC and nosocomial BSI. Results Data from 10,890 preterm infants in 44 neonatal wards was included in this study. Incidences of NEC and BSI were 2.5% (n = 274) and 15.0%, (n = 1631), respectively. Mortality rate was 6.1% (n = 665). The use of dual-strain probiotics significantly reduced the risk of NEC (HR = 0.48; 95% CI = 0.38–0.62), overall mortality (HR = 0.60, 95% CI = 0.44–0.83), mortality after NEC (HR = 0.51, 95% CI = 0.26–0.999) and nosocomial BSI (HR = 0.89, 95% CI = 0.81–0.98). These effects were even more pronounced in the subgroup analysis of preterm infants with birth weights below 1,000 g. Conclusion In order to reduce NEC and mortality in preterm infants, it is advisable to add routine prophylaxis with dual-strain probiotics to clinical practice in neonatal wards. PMID:27332554

  12. Thin film strain transducer

    NASA Astrophysics Data System (ADS)

    Rand, J. L.

    1981-01-01

    Previous attempts to develop an appropriate sensor for measuring the stress or strain of high altitude balloons during flight are reviewed as well as the various conditions that must be met by such a device. The design, development and calibration of a transducer which promises to satisfy the necessary design constraints are described. The thin film strain transducer has a low effective modulus so as not to interfere with the strain that would naturally occur in the balloon. In addition, the transducer has a high sensitivity to longitudinal strain (7.216 mV/V/unit strain) which is constant for all temperature from room temperature to -80 C and all strains from 5 percent compression to 10 percent tensile strain. At the same time, the sensor is relatively insensitive (0.27 percent) to transverse forces. The device has a standard 350 ohm impedance which is compatible with available bridge balance, amplification and telemetry instrumentation now available for balloon flight. Recommendations are included for improved coatings to provide passive thermal control as well as model, tethered and full scale flight testing.

  13. Strain gauge installation tool

    DOEpatents

    Conard, Lisa Marie

    1998-01-01

    A tool and a method for attaching a strain gauge to a test specimen by maaining alignment of, and applying pressure to, the strain gauge during the bonding of the gauge to the specimen. The tool comprises rigid and compliant pads attached to a spring-loaded clamp. The pads are shaped to conform to the specimen surface to which the gauge is to be bonded. The shape of the pads permits the tool to align itself to the specimen and to maintain alignment of the gauge to the specimen during the bond curing process. A simplified method of attaching a strain gauge is provided by use of the tool.

  14. Sprains and Strains

    MedlinePlus

    ... Typically, people with a strain experience pain, limited motion, muscle spasms, and possibly muscle weakness. They also ... program designed to prevent stiffness, improve range of motion, and restore the joint's normal flexibility and strength. ...

  15. Strains and Sprains

    MedlinePlus

    ... in the joint or muscle swelling and bruising warmth and redness of the injured area difficulty moving ... looks "bent" or misshapen signs of infection (increased warmth, redness, streaks, swelling, and pain) a strain or ...

  16. Strain and magnetic remanence

    NASA Astrophysics Data System (ADS)

    Borradaile, Graham John

    1993-05-01

    Experimental data may be compatible with the hypothesis that a single direction of magnetic remanence rotates as a rigid marker with strains up to 40% shortening in coaxial, perfect flattening ( X = Y > Z). Detailed agreement with the passive line model is relatively poor for the specimens in which remanance is carried by magnetite. However, for this range of strains the differences with the passive line model (Wettstein's equation) are so slight that the latter model may be more easily employed to de-strain or restore deformed remanance to its original attitude. In the case of hematite-bearing remanences, the differences between the passive line and rigid marker model are even smaller because of the higher aspect ratios of grains of hematite. Therefore it is suggested that Wettstein's equation may be safely used to restore remanence after even higher strains, where the remanence is carried by hematite.

  17. Cholesterol-Lowering Potentials of Lactic Acid Bacteria Based on Bile-Salt Hydrolase Activity and Effect of Potent Strains on Cholesterol Metabolism In Vitro and In Vivo

    PubMed Central

    Lin, Pei-Pei; Hsieh, You-Miin; Zhang, Zi-yi; Wu, Hui-Ching; Huang, Chun-Chih

    2014-01-01

    This study collected different probiotic isolates from animal and plant sources to evaluate the bile-salt hydrolase activity of probiotics in vitro. The deconjugation potential of bile acid was determined using high-performance liquid chromatography. HepG2 cells were cultured with probiotic strains with high BSH activity. The triglyceride (TG) and apolipoprotein B (apo B) secretion by HepG2 cells were evaluated. Our results show that the BSH activity and bile-acid deconjugation abilities of Pediococcus acidilactici NBHK002, Bifidobacterium adolescentis NBHK006, Lactobacillus rhamnosus NBHK007, and Lactobacillus acidophilus NBHK008 were higher than those of the other probiotic strains. The cholesterol concentration in cholesterol micelles was reduced within 24 h. NBHK007 reduced the TG secretion by 100% after 48 h of incubation. NBHK002, NBHK006, and NBHK007 could reduce apo B secretion by 33%, 38%, and 39%, respectively, after 24 h of incubation. The product PROBIO S-23 produced a greater decrease in the total concentration of cholesterol, low-density lipoprotein, TG, and thiobarbituric acid reactive substance in the serum or livers of hamsters with hypercholesterolemia compared with that of hamsters fed with a high-fat and high-cholesterol diet. These results show that the three probiotic strains of lactic acid bacteria are better candidates for reducing the risk of cardiovascular disease. PMID:25538960

  18. Fates of acid-resistant and non-acid-resistant Shiga toxin-producing Escherichia coli strains in ruminant digestive contents in the absence and presence of probiotics.

    PubMed

    Chaucheyras-Durand, Frédérique; Faqir, Fahima; Ameilbonne, Aurélie; Rozand, Christine; Martin, Christine

    2010-02-01

    Healthy ruminants are the main reservoir of Shiga toxin-producing Escherichia coli (STEC). During their transit through the ruminant gastrointestinal tract, STEC encounters a number of acidic environments. As all STEC strains are not equally resistant to acidic conditions, the purpose of this study was to investigate whether acid resistance confers an ecological advantage to STEC strains in ruminant digestive contents and whether acid resistance mechanisms are induced in the rumen compartment. We found that acid-resistant STEC survived at higher rates during prolonged incubation in rumen fluid than acid-sensitive STEC and that they resisted the highly acidic conditions of the abomasum fluid, whereas acid-sensitive strains were killed. However, transit through the rumen contents allowed acid-sensitive strains to survive in the abomasum fluid at levels similar to those of acid-resistant STEC. The acid resistance status of the strains had little influence on STEC growth in jejunal and cecal contents. Supplementation with the probiotic Saccharomyces cerevisiae CNCM I-1077 or Lactobacillus acidophilus BT-1386 led to killing of all of the strains tested during prolonged incubation in the rumen contents, but it did not have any influence in the other digestive compartments. In addition, S. cerevisiae did not limit the induction of acid resistance in the rumen fluid. Our results indicate that the rumen compartment could be a relevant target for intervention strategies that could both limit STEC survival and eliminate induction of acid resistance mechanisms in order to decrease the number of viable STEC cells reaching the hindgut and thus STEC shedding and food contamination.

  19. Strain isolated ceramic coatings

    NASA Technical Reports Server (NTRS)

    Tolokan, R. P.; Brady, J. B.; Jarrabet, G. P.

    1985-01-01

    Plasma sprayed ceramic coatings are used in gas turbine engines to improve component temperature capability and cooling air efficiency. A compliant metal fiber strain isolator between a plasma sprayed ceramic coating and a metal substrate improves ceramic durability while allowing thicker coatings for better insulation. Development of strain isolated coatings has concentrated on design and fabrication of coatings and coating evaluation via thermal shock testing. In thermal shock testing, five types of failure are possible: buckling failure im compression on heat up, bimetal type failure, isothermal expansion mismatch failure, mudflat cracking during cool down, and long term fatigue. A primary failure mode for thermally cycled coatings is designated bimetal type failure. Bimetal failure is tensile failure in the ceramic near the ceramic-metal interface. One of the significant benefits of the strain isolator is an insulating layer protecting the metal substrate from heat deformation and thereby preventing bimetal type failure.

  20. Strain avalanches in plasticity

    NASA Astrophysics Data System (ADS)

    Argon, A. S.

    2013-09-01

    Plastic deformation at the mechanism level in all solids occurs in the form of discrete thermally activated individual stress relaxation events. While there are clear differences in mechanisms between dislocation mediated events in crystalline solids and by individual shear transformations in amorphous metals and semiconductors, such relaxation events interact strongly to form avalanches of strain bursts. In all cases the attendant distributions of released energy as amplitudes of acoustic emissions, or in serration amplitudes in flow stress, the levels of strain bursts are of fractal character with fractal exponents in the range from -1.5 to -2.0, having the character of phenomena of self-organized criticality, SOC. Here we examine strain avalanches in single crystals of ice, hcp metals, the jerky plastic deformations of nano-pillars of fcc and bcc metals deforming in compression, those in the plastic flow of bulk metallic glasses, all demonstrating the remarkable universality of character of plastic relaxation events.

  1. Strain gauge installation tool

    DOEpatents

    Conard, L.M.

    1998-06-16

    A tool and a method are disclosed for attaching a strain gauge to a test specimen by maintaining alignment of, and applying pressure to, the strain gauge during the bonding of the gauge to the specimen. The tool comprises rigid and compliant pads attached to a spring-loaded clamp. The pads are shaped to conform to the specimen surface to which the gauge is to be bonded. The shape of the pads permits the tool to align itself to the specimen and to maintain alignment of the gauge to the specimen during the bond curing process. A simplified method of attaching a strain gauge is provided by use of the tool. 6 figs.

  2. Radio frequency strain monitor

    NASA Technical Reports Server (NTRS)

    Heyman, Joseph S. (Inventor); Rogowski, Robert S. (Inventor); Holben, Jr., Milford S. (Inventor)

    1989-01-01

    A radio frequency strain monitor includes a voltage controlled oscillator for generating an oscillating signal that is input into a propagation path. The propagation path is preferably bonded to the surface of a structure to be monitored and produces a propagated signal. A phase difference between the oscillating and propagated signals is detected and maintained at a substantially constant value which is preferably a multiple of 90.degree. by changing the frequency of the oscillating signal. Any change in frequency of the oscillating signal provides an indication of strain in the structure to which the propagation path is bonded.

  3. Muscle strain injuries.

    PubMed

    Garrett, W E

    1996-01-01

    One of the most common injuries seen in the office of the practicing physician is the muscle strain. Until recently, little data were available on the basic science and clinical application of this basic science for the treatment and prevention of muscle strains. Studies in the last 10 years represent action taken on the direction of investigation into muscle strain injuries from the laboratory and clinical fronts. Findings from the laboratory indicate that certain muscles are susceptible to strain injury (muscles that cross multiple joints or have complex architecture). These muscles have a strain threshold for both passive and active injury. Strain injury is not the result of muscle contraction alone, rather, strains are the result of excessive stretch or stretch while the muscle is being activated. When the muscle tears, the damage is localized very near the muscle-tendon junction. After injury, the muscle is weaker and at risk for further injury. The force output of the muscle returns over the following days as the muscle undertakes a predictable progression toward tissue healing. Current imaging studies have been used clinically to document the site of injury to the muscle-tendon junction. The commonly injured muscles have been described and include the hamstring, the rectus femoris, gastrocnemius, and adductor longus muscles. Injuries inconsistent with involvement of a single muscle-tendon junction proved to be at tendinous origins rather than within the muscle belly. Important information has also been provided regarding injuries with poor prognosis, which are potentially repairable surgically, including injuries to the rectus femoris muscle, the hamstring origin, and the abdominal wall. Data important to the management of common muscle injuries have been published. The risks of reinjury have been documented. The early efficacy and potential for long-term risks of nonsteroidal antiinflammatory agents have been shown. New data can also be applied to the field

  4. Sadovskii vortex in strain

    NASA Astrophysics Data System (ADS)

    Freilich, Daniel; Llewellyn Smith, Stefan

    2015-11-01

    Sadovskii vortices are patches of fluid with uniform vorticity surrounded by a vortex sheet. They were first constructed as models for wakes behind bluff objects. We investigate the Sadovskii vortex in a straining field and examine limiting cases to validate our computational method. One limit is the patch vortex in strain (Moore & Saffman, Aircraft wake turbulence and its detection 1971), where there is no vortex sheet. We solve this as a free-boundary problem, and show that a simple method using the Biot-Savart law quickly gives solutions for stable shapes. When used for the more elongated (stronger straining field) situations, the method also leads to new vortex shapes. In the hollow vortex case, where there is no vortex patch and the circulation is entirely due to the vortex sheet (Llewellyn Smith and Crowdy, J. Fluid Mech. 691 2012), we use the Birkhoff-Rott equation to calculate the velocity of the fluid on the vortex boundary. The combination of these two methods can then be used to calculate the shape and velocity field of the Sadovksii vortex in strain.

  5. Strain gage barometric transmitter

    NASA Technical Reports Server (NTRS)

    Viton, P.

    1977-01-01

    A strain gage barometric transmitter for measuring the atmospheric pressure in severe environmental conditions is described. This equipment specifications are presented and its performance assessed. It is shown that this barometric sensor can measure the atmospheric pressure with a precision of 0.5 mb during a 6 month period.

  6. Hamstring strain - aftercare

    MedlinePlus

    ... not to push yourself too hard or too fast. A hamstring strain can recur, or your hamstring may tear. Talk to your provider before returning to work or any physical activity. Returning to normal activity too early can cause re-injury.

  7. Repetitive strain injury.

    PubMed

    Al-Otaibi, S T

    2001-05-01

    Repetitive strain injury is a group of musculoskeletal disorders affecting muscles, tendons, nerves and blood vessels. These disorders could be attributed to occupational causes; however non-occupational causes should be excluded. The management of these cases required a multidisciplinary team approach.

  8. Balloon film strain measurement

    NASA Astrophysics Data System (ADS)

    Rand, James L.

    In order to understand the state of stress in scientific balloons, a need exists for the measurement of film deformation in flight. The results of a flight test program are reported where material strain was measured for the first time during the inflation, launch, ascent and float of a typical natural shape, zero pressure scientific balloon.

  9. Potential probiotic attributes of a new strain of Bacillus coagulans CGMCC 9951 isolated from healthy piglet feces.

    PubMed

    Gu, Shao-Bin; Zhao, Li-Na; Wu, Ying; Li, Shi-Chang; Sun, Jian-Rui; Huang, Jing-Fang; Li, Dan-Dan

    2015-06-01

    A new strain of Bacillus coagulans CGMCC 9551, which has a broad range of antibacterial activities against six main pathogenic bacteria including Escherichia coli O8, Staphylococcus aureus, Salmonella enterica subsp. enterica serovar enteritidis, Streptococcus suis, Listeria monocytogenes and Pasteurella multocida, was isolated from healthy piglet feces. In adhesion assay, the isolate exhibited a stronger adhesion to pig intestinal mucus than that of B. subtilis JT143 and L. acidophilus LY24 respectively isolated from BioPlus(®)2B and FloraFIT(®) Probiotics (P < 0.05). The adhesion activity reached 44.5 ± 3.2, 48.9 ± 2.6, 42.6 ± 3.3 and 37.6 ± 2.4% to jejunum, ileum, transverse colon and sigmoid colon, separately. The survival rate of B. coagulans CGMCC 9551 was reduced by only 20% at 4 h exposure under 0.9% w/v bile salt. The strain was fully resistant to pH 2 for 2 h with 90.1 ± 3.5% survival and susceptible to 15 antibiotics commonly used in veterinary medicine. Additionally, the bacteria showed amylase, protease and cellulase activities. The safety assessment demonstrated the lack of toxicity potential in B. coagulans CGMCC 9551 by ligated rabbit ileal loop assay, acute and subchronic toxicity test. These results implied that that the new strain of B. coagulans CGMCC 9951 isolated from healthy piglet feces has promising probiotic characteristics and offers desirable opportunities for its successful commercialization as one excellent candidate probiotic.

  10. Highly stretchable miniature strain sensor for large dynamic strain measurement

    DOE PAGES

    Song, Bo; Yao, Shurong; Nie, Xu; ...

    2016-01-01

    In this paper, a new type of highly stretchable strain sensor was developed to measure large strains. The sensor was based on the piezo-resistive response of carbon nanotube (CNT)/polydimethylsiloxane (PDMS) composite thin films. The piezo-resistive response of CNT composite gives accurate strain measurement with high frequency response, while the ultra-soft PDMS matrix provides high flexibility and ductility for large strain measurement. Experimental results show that the CNT/PDMS sensor measures large strains (up to 8 %) with an excellent linearity and a fast frequency response. The new miniature strain sensor also exhibits much higher sensitivities than the conventional foil strain gages,more » as its gauge factor is 500 times of that of the conventional foil strain gages.« less

  11. Highly stretchable miniature strain sensor for large dynamic strain measurement

    SciTech Connect

    Song, Bo; Yao, Shurong; Nie, Xu; Yu, Xun; Blecke, Jill

    2016-01-01

    In this paper, a new type of highly stretchable strain sensor was developed to measure large strains. The sensor was based on the piezo-resistive response of carbon nanotube (CNT)/polydimethylsiloxane (PDMS) composite thin films. The piezo-resistive response of CNT composite gives accurate strain measurement with high frequency response, while the ultra-soft PDMS matrix provides high flexibility and ductility for large strain measurement. Experimental results show that the CNT/PDMS sensor measures large strains (up to 8 %) with an excellent linearity and a fast frequency response. The new miniature strain sensor also exhibits much higher sensitivities than the conventional foil strain gages, as its gauge factor is 500 times of that of the conventional foil strain gages.

  12. Strain patterns and strain accumulation along plate margins

    NASA Technical Reports Server (NTRS)

    Savage, J. C.

    1978-01-01

    Observations of strain accumulation along plate margins in Japan, New Zealand, and the United States indicate that: (1) a typical maximum rate of secular strain accumulation is on the order of 0.3 ppm/a, (2) a substantial part of the strain accumulation process can be attributed to slip at depth on the major plate boundary faults, and (3) some plastic deformation in a zone 100 km or more in width is apparently involved in the strain accumulation process.

  13. High temperature strain gages

    NASA Technical Reports Server (NTRS)

    Gregory, Otto J. (Inventor); You, Tao (Inventor)

    2011-01-01

    A ceramic strain gage based on reactively sputtered indium-tin-oxide (ITO) thin films is used to monitor the structural integrity of components employed in aerospace propulsion systems operating at temperatures in excess of 1500.degree. C. A scanning electron microscopy (SEM) of the thick ITO sensors reveals a partially sintered microstructure comprising a contiguous network of submicron ITO particles with well defined necks and isolated nanoporosity. Densification of the ITO particles was retarded during high temperature exposure with nitrogen thus stabilizing the nanoporosity. ITO strain sensors were prepared by reactive sputtering in various nitrogen/oxygen/argon partial pressures to incorporate more nitrogen into the films. Under these conditions, sintering and densification of the ITO particles containing these nitrogen rich grain boundaries was retarded and a contiguous network of nano-sized ITO particles was established.

  14. Strained Ring Energetic Binders

    DTIC Science & Technology

    1993-08-27

    polyhomobenzvalene ( PHBV ). PHBV was not found to have the mechanical instability problems of PBV, but was still thermally unstable (Tonset - 660C, Tmax - 1090C...DISCUSSION 4 Polybenzvalene (PBV) 4 Polyhomobenzvalene ( PHBV ) 6 Chain-Transfer Studies 11 CONCLUSIONS 15 EXPERIMENTAL PROCEDURES 16 .F 4E 19 APPENDICES A...strained ring polymers similar to PBV are known. The investigation of one of these polymers, polyhomobenzvalene ( PHBV ), is also described in this report

  15. Strain Gage Signal Interpretation.

    DTIC Science & Technology

    1986-02-01

    blades and vanes in many engines have been collected, played back and examined. The engine types encompass GE’s stable of turbine engines from the small...aeromechanical engineer . 1.3 SUMMARY OF RESULTS Strain gage signals from vibrating rotor blades and vanes were collected, examined, classified, and generalized...turboprops, to turbojets and to the large high bypass turbofan engines . Test conditions include all the phases that are investigated

  16. Strain Measurement - Unidirectional.

    DTIC Science & Technology

    1983-04-20

    a ballpoint pen or a rounded piece of brass rod. If critical alignment is not necessary, gage lines may be located outside the immediate gage location...supplemented as needed by tabulated values. If the test design includes specification limits for the values, they should be included on the plots. Plots of...enough baseline before the event to allow estimation of the noise and stability. If the strain is to be correlated to specific events, the events should

  17. What Are Sprains and Strains?

    MedlinePlus

    ... hands and arms a lot. Examples are gymnastics, tennis, rowing, and golf. People who play these sports sometimes strain their hand or arm. Elbow strains can also happen when playing sports. What ...

  18. Synbiotic (Lactobacillus rhamnosus+Lactobacillus acidophilus+inulin) attenuates oxidative stress and colonic damage in 1,2 dimethylhydrazine dihydrochloride-induced colon carcinogenesis in Sprague-Dawley rats: a long-term study.

    PubMed

    Verma, Angela; Shukla, Geeta

    2014-11-01

    The inexorable increase in the incidence of colorectal cancer has led to growing interest in its prevention by natural interventions. Thus, the present study was designed with the aim of delineating the antioxidative and antitumorigenic effects of synbiotics in experimental colon carcinogenesis. It was observed that administration of a synbiotic, before 1,2 dimethylhydrazine dihydrochloride (DMH)-induced colon carcinogenesis in Sprague-Dawley rats, led to increased body weight and growth rate, and decreased tumor incidence compared with the DMH-only-treated group of animals. Most notably, the level of malondialdehyde, a measure of lipid peroxidation, decreased, and levels of the antioxidants, glutathione reductase, superoxide dismutase, and glutathione peroxidase increased in animals in the Lactobacillus acidophilus+DMH, inulin+DMH, and synbiotic+DMH groups compared with DMH-only-treated animals. Histopathological observations of the colon also documented fewer dysplastic changes and increased the number of goblet cells in the probiotic-treated, prebiotic-treated, and synbiotic-treated animals compared with DMH-only-treated animals. Taken together, the present study shows that the use of synbiotics is a better prophylactic strategy than the use of probiotic and prebiotic alone because of the greater increase in antioxidants associated with the higher degree of attenuation of DMH-induced tumorigenesis.

  19. Synbiotic Lactobacillus acidophilus NCFM and cellobiose does not affect human gut bacterial diversity but increases abundance of lactobacilli, bifidobacteria and branched-chain fatty acids: a randomized, double-blinded cross-over trial.

    PubMed

    van Zanten, Gabriella C; Krych, Lukasz; Röytiö, Henna; Forssten, Sofia; Lahtinen, Sampo J; Abu Al-Soud, Waleed; Sørensen, Søren; Svensson, Birte; Jespersen, Lene; Jakobsen, Mogens

    2014-10-01

    Probiotics, prebiotics, and combinations thereof, that is synbiotics, have been reported to modulate gut microbiota of humans. In this study, effects of a novel synbiotic on the composition and metabolic activity of human gut microbiota were investigated. Healthy volunteers (n = 18) were enrolled in a double-blinded, randomized, and placebo-controlled cross-over study and received synbiotic [Lactobacillus acidophilus NCFM (10(9) CFU) and cellobiose (5 g)] or placebo daily for 3 weeks. Fecal samples were collected and lactobacilli numbers were quantified by qPCR. Furthermore, 454 tag-encoded amplicon pyrosequencing was used to monitor the effect of synbiotic on the composition of the microbiota. The synbiotic increased levels of Lactobacillus spp. and relative abundances of the genera Bifidobacterium, Collinsella, and Eubacterium while the genus Dialister was decreased (P < 0.05). No other effects were found on microbiota composition. Remarkably, however, the synbiotic increased concentrations of branched-chain fatty acids, measured by gas chromatography, while short-chain fatty acids were not affected.

  20. Effect of salt stress on morphology and membrane composition of Lactobacillus acidophilus, Lactobacillus casei, and Bifidobacterium bifidum, and their adhesion to human intestinal epithelial-like Caco-2 cells.

    PubMed

    Gandhi, Akanksha; Shah, Nagendra P

    2016-04-01

    The effects of NaCl reduction (10.0, 7.5, 5.0, 2.5, and 0% NaCl) and its substitution with KCl (50% substitution at each given concentration) on morphology of Lactobacillus acidophilus, Lactobacillus casei, and Bifidobacterium longum was investigated using transmission electron microscopy. Changes in membrane composition, including fatty acids and phospholipids, were investigated using gas chromatography and thin layer chromatography. Adhesion ability of these bacteria to human intestinal epithelial-like Caco-2 cells, as affected by NaCl and its substitution with KCl, was also evaluated. Bacteria appeared elongated and the intracellular content appeared contracted when subjected to salt stress, as observed by transmission electron microscopy. Fatty acid content was altered with an increase in the ratio of unsaturated to saturated fatty acid content on increasing the NaCl-induced stress. Among the phospholipids, phosphatidylglycerol was reduced, whereas phosphatidylinositol and cardioplipin were increased when the bacteria were subjected to salt stress. There was a significant reduction in adhesion ability of the bacteria to Caco-2 cells when cultured in media supplemented with NaCl; however, the adhesion ability was improved on substitution with KCl at a given total salt concentration. The findings provide insights into bacterial membrane damage caused by NaCl.

  1. Strain balanced quantum posts

    SciTech Connect

    Alonso-Alvarez, D.; Alen, B.; Ripalda, J. M.; Llorens, J. M.; Taboada, A. G.; Briones, F.; Roldan, M. A.; Hernandez-Saz, J.; Hernandez-Maldonado, D.; Herrera, M.; Molina, S. I.

    2011-04-25

    Quantum posts are assembled by epitaxial growth of closely spaced quantum dot layers, modulating the composition of a semiconductor alloy, typically InGaAs. In contrast with most self-assembled nanostructures, the height of quantum posts can be controlled with nanometer precision, up to a maximum value limited by the accumulated stress due to the lattice mismatch. Here, we present a strain compensation technique based on the controlled incorporation of phosphorous, which substantially increases the maximum attainable quantum post height. The luminescence from the resulting nanostructures presents giant linear polarization anisotropy.

  2. Antipathogenic activity of probiotics against Salmonella Typhimurium and Clostridium difficile in anaerobic batch culture systems: is it due to synergies in probiotic mixtures or the specificity of single strains?

    PubMed

    Tejero-Sariñena, Sandra; Barlow, Janine; Costabile, Adele; Gibson, Glenn R; Rowland, Ian

    2013-12-01

    Probiotics are currently being investigated for prevention of infections caused by enteric pathogens. The aim of this in vitro study was to evaluate the influence of three single probiotics: Lactobacillus casei NCIMB 30185 (PXN 37), Lactobacillus acidophilus NCIMB 30184 (PXN 35), Bifidobacterium breve NCIMB 30180 (PXN 25) and a probiotic mixture containing the above strains plus twelve other strains belonging to the Lactobacillus, Bifidobacterium, Lactococcus, Streptococcus and Bacillus genera on the survival of Salmonella Typhimurium and Clostridium difficile using pH-controlled anaerobic batch cultures containing mixed faecal bacteria. Changes in relevant bacterial groups and effects of probiotic addition on survival of the two pathogens were assessed over 24 h. Quantitative analysis of bacterial populations revealed that there was a significant increase in lactobacilli and/or bifidobacteria numbers, depending on probiotic addition, compared with the control (no added probiotic). There was also a significant reduction in S. Typhimurium and C. difficile numbers in the presence of certain probiotics compared with controls. Of the probiotic treatments, two single strains namely L. casei NCIMB 30185 (PXN 37), and B. breve NCIMB 30180 (PXN 25) were the most potent in reducing the numbers of S. Typhimurium and C. difficile. In addition, the supplementation with probiotics into the systems influenced some fermentations parameters. Acetate was found in the largest concentrations in all vessels and lactate and formate were generally detected in higher amounts in vessels with probiotic addition compared to controls.

  3. Sadovskii vortex in strain

    NASA Astrophysics Data System (ADS)

    Freilich, Daniel; Llewellyn Smith, Stefan

    2014-11-01

    A Sadovskii vortex is a patch of fluid with uniform vorticity surrounded by a vortex sheet. Using a boundary element type method, we investigate the steady states of this flow in an incompressible, inviscid straining flow. Outside the vortex, the fluid is irrotational. In the limiting case where the entire circulation is due to the vortex patch, this is a patch vortex (Moore & Saffman, Aircraft wake turbulence and its detection 1971). In the other limiting case, where all the circulation is due to the vortex sheet, this is a hollow vortex (Llewellyn Smith and Crowdy, J. Fluid Mech. 691, 2012). This flow has two governing nondimensional parameters, relating the strengths of the straining field, vortex sheet, and patch vorticity. We study the relationship between these two parameters, and examine the shape of the resulting vortices. We also work towards a bifurcation diagram of the steady states of the Sadovskii vortex in an attempt to understand the connection between vortex sheet and vortex patch desingularizations of the point vortex. Support from NSF-CMMI-0970113.

  4. Repetitive strain injury.

    PubMed

    van Tulder, Maurits; Malmivaara, Antti; Koes, Bart

    2007-05-26

    Repetitive strain injury remains a controversial topic. The term repetitive strain injury includes specific disorders such as carpal tunnel syndrome, cubital tunnel syndrome, Guyon canal syndrome, lateral epicondylitis, and tendonitis of the wrist or hand. The diagnosis is usually made on the basis of history and clinical examination. Large high-quality studies using newer imaging techniques, such as MRI and ultrasonography are few. Consequently, the role of such imaging in diagnosis of upper limb disorders remains unclear. In many cases, no specific diagnosis can be established and complaints are labelled as non-specific. Little is known about the effectiveness of treatment options for upper limb disorders. Strong evidence for any intervention is scarce and the effect, if any, is mainly short-term pain relief. Exercise is beneficial for non-specific upper limb disorders. Immobilising hand braces and open carpal tunnel surgery release are beneficial for carpal tunnel syndrome, and topical and oral non-steroidal anti-inflammatory drugs, and corticosteroid injections are helpful for lateral epicondylitis. Exercise is probably beneficial for neck pain, as are corticosteroid injections and exercise for shoulder pain. Although upper limb disorders occur frequently in the working population, most trials have not exclusively included a working population or assessed effects on work-related outcomes. Further high-quality trials should aim to include sufficient sample sizes, working populations, and work-related outcomes.

  5. Strain Pattern in Supercooled Liquids

    NASA Astrophysics Data System (ADS)

    Illing, Bernd; Fritschi, Sebastian; Hajnal, David; Klix, Christian; Keim, Peter; Fuchs, Matthias

    2016-11-01

    Investigations of strain correlations at the glass transition reveal unexpected phenomena. The shear strain fluctuations show an Eshelby-strain pattern [˜cos (4 θ ) /r2 ], characteristic of elastic response, even in liquids, at long times. We address this using a mode-coupling theory for the strain fluctuations in supercooled liquids and data from both video microscopy of a two-dimensional colloidal glass former and simulations of Brownian hard disks. We show that the long-ranged and long-lived strain signatures follow a scaling law valid close to the glass transition. For large enough viscosities, the Eshelby-strain pattern is visible even on time scales longer than the structural relaxation time τ and after the shear modulus has relaxed to zero.

  6. The Effect of Lactobacillus plantarum ATCC 8014 and Lactobacillus acidophilus NCFM Fermentation on Antioxidant Properties of Selected in Vitro Sprout Culture of Orthosiphon aristatus (Java Tea) as a Model Study.

    PubMed

    Hunaefi, Dase; Akumo, Divine N; Riedel, Heidi; Smetanska, Iryna

    2012-09-26

    High rosmarinic acid (RA) productivity has been achieved by applying jasmonic acid and yeast extract elicitors to the in vitro sprout culture of Orthosiphon aritatus (IOSC). The highest RA accumulation from three solvents was detected in IOSC after treatment with yeast extract (5 g/L). HPLC analysis clearly confirmed a drastic increase in RA subjected to yeast extract elicitation. Therefore, this yeast extract elicited IOSC was chosen for a lactic acid bacteria (LAB) fermentation study as a model system. This selected IOSC was subjected to different types of LAB fermentations (Lactobacillus plantarum ATCC 8014 and Lactobacillus acidophilus NCFM) for different periods of time 24, 48 and 72 h. The LAB fermentations consisted of solid state fermentations (SSF) and liquid state fermentations (LSF) in a Digital Control Unit (DCU) fermenter system. The aim was to determine the effect of fermentation on the antioxidant properties of the plant extract. Results indicated that all types of LAB fermentation decreased the level of RA and total phenolics, however, a slight increase in total flavonoids and flavonols was observed in SSF samples. HPLC results confirmed that the longer the fermentation, the greater the reduction in RA content. The highest reduction was obtained in the sample of LSF inoculated with L. plantarum for a period of 72 h. The temperature of fermentation (37 °C) was predicted as contributing to the declining level in RA content. The loss in RA was concomitant with a loss of total antioxidant activity (1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging activity, Trolox Equivalent Antioxidant Capacity (TEAC), and Superoxide Dismutase (SOD)-like activity). These results indicate that RA is the major contributor to the antioxidant activity of this plant.

  7. The Effect of Lactobacillus plantarum ATCC 8014 and Lactobacillus acidophilus NCFM Fermentation on Antioxidant Properties of Selected in Vitro Sprout Culture of Orthosiphon aristatus (Java Tea) as a Model Study

    PubMed Central

    Hunaefi, Dase; Akumo, Divine N.; Riedel, Heidi; Smetanska, Iryna

    2012-01-01

    High rosmarinic acid (RA) productivity has been achieved by applying jasmonic acid and yeast extract elicitors to the in vitro sprout culture of Orthosiphon aritatus (IOSC). The highest RA accumulation from three solvents was detected in IOSC after treatment with yeast extract (5 g/L). HPLC analysis clearly confirmed a drastic increase in RA subjected to yeast extract elicitation. Therefore, this yeast extract elicited IOSC was chosen for a lactic acid bacteria (LAB) fermentation study as a model system. This selected IOSC was subjected to different types of LAB fermentations (Lactobacillus plantarum ATCC 8014 and Lactobacillus acidophilus NCFM) for different periods of time 24, 48 and 72 h. The LAB fermentations consisted of solid state fermentations (SSF) and liquid state fermentations (LSF) in a Digital Control Unit (DCU) fermenter system. The aim was to determine the effect of fermentation on the antioxidant properties of the plant extract. Results indicated that all types of LAB fermentation decreased the level of RA and total phenolics, however, a slight increase in total flavonoids and flavonols was observed in SSF samples. HPLC results confirmed that the longer the fermentation, the greater the reduction in RA content. The highest reduction was obtained in the sample of LSF inoculated with L. plantarum for a period of 72 h. The temperature of fermentation (37 °C) was predicted as contributing to the declining level in RA content. The loss in RA was concomitant with a loss of total antioxidant activity (1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging activity, Trolox Equivalent Antioxidant Capacity (TEAC), and Superoxide Dismutase (SOD)-like activity). These results indicate that RA is the major contributor to the antioxidant activity of this plant. PMID:26787613

  8. Lactobacillus acidophilus La5, Bifidobacterium BB12, and Lactobacillus casei DN001 modulate gene expression of subset specific transcription factors and cytokines in peripheral blood mononuclear cells of obese and overweight people.

    PubMed

    Zarrati, Mitra; Shidfar, Farzad; Nourijelyani, Keramat; Mofid, Vahid; Hossein zadeh-Attar, Mohammad Javad; Bidad, Katayoon; Najafi, Forouzan; Gheflati, Zahra; Chamari, Maryam; Salehi, Eisa

    2013-01-01

    Probiotics are believed to have interaction with immune cells through sustained effects on gene expression of different cytokines and transcription factors. The present randomized doubled-blind controlled clinical trial was performed recruiting 75 individuals with BMI 25-35, who were randomly assigned to the following three groups: Group 1 (n = 25) who consumed regular yogurt as part of a low calorie diet [RLCD], group 2 (n = 25) who received probiotic yogurt with a LCD [PLCD] and group 3 (n = 25) who consumed probiotic yogurt without LCD [PWLCD] for 8 week. Participants in PLCD and PWLCD groups received 200 g/day yogurt containing Lactobacillus acidophilus La5, Bifidobacterium Bb12, and lactobacillus casei DN001 10(8) cfu/gr. The expression of the FOXP3, T-bet, GATA3, TNF-α, IFN-γ, TGF-β, and ROR-γt in PBMCs genes were assessed, before and after intervention. In three groups, ROR-γt expression was reduced (P = 0.007) and FOXP3 was increased (P < 0.001). The expression of TNFα, TGFβ, and GATA3 genes did not change among all groups after intervention. Interestingly, the expression of T-bet gene, which was significantly decreased in PLCD and PWLCD groups (P < 0.001), whereas gene expression of IFN-γ decreased in all three groups. Our results suggest that weight loss diet and probiotic yogurt had synergistic effects on T-cell subset specific gene expression in peripheral blood mononuclear cells among overweight and obese individuals.

  9. Hydrogen production from microbial strains

    DOEpatents

    Harwood, Caroline S; Rey, Federico E

    2012-09-18

    The present invention is directed to a method of screening microbe strains capable of generating hydrogen. This method involves inoculating one or more microbes in a sample containing cell culture medium to form an inoculated culture medium. The inoculated culture medium is then incubated under hydrogen producing conditions. Once incubating causes the inoculated culture medium to produce hydrogen, microbes in the culture medium are identified as candidate microbe strains capable of generating hydrogen. Methods of producing hydrogen using one or more of the microbial strains identified as well as the hydrogen producing strains themselves are also disclosed.

  10. Strain relaxation in nanopatterned strained silicon round pillars

    NASA Astrophysics Data System (ADS)

    Himcinschi, C.; Singh, R.; Radu, I.; Milenin, A. P.; Erfurth, W.; Reiche, M.; Gösele, U.; Christiansen, S. H.; Muster, F.; Petzold, M.

    2007-01-01

    Periodic arrays of strained Si (sSi) round nanopillars were fabricated on sSi layers deposited on SiGe virtual substrates by electron-beam lithography and subsequent reactive-ion etching. The strain in the patterned sSi nanopillars was determined using high-resolution UV micro-Raman spectroscopy. The strain relaxes significantly upon nanostructuring: from 0.9% in the unpatterned sSi layer to values between 0.22% and 0.57% in the round sSi pillars with diameters from 100 up to 500nm. The strain distribution in the sSi nanopillars was analyzed by finite element (FE) modeling. The FE calculations confirm the strain relaxation after patterning, in agreement with the results obtained from Raman spectroscopy.

  11. Adaptor for Measuring Principal Strains with Tuckerman Strain Gage

    NASA Technical Reports Server (NTRS)

    Mcpherson, A E

    1943-01-01

    An adapter is described which uses three Tuckerman optical strain gages to measure the displacement of the three vortices of an equilateral triangle along lines 120 degrees apart. These displacements are substituted in well-known equations in order to compute the magnitude and direction of the principal strains. Tests of the adaptor indicate that principal strains over a gage length of 1.42 inch may be measured with a systematic error not exceeding 4 percent and a mean observational error of the order of + or minus 0.000006. The maximum observed error in strain was of the order of 0.00006. The directions of principal strains for unidirectional stress were measured with the adaptor with an average error of the order of 1 degree.

  12. Strained graphene Hall bar

    NASA Astrophysics Data System (ADS)

    Milovanović, S. P.; Peeters, F. M.

    2017-02-01

    The effects of strain, induced by a Gaussian bump, on the magnetic field dependent transport properties of a graphene Hall bar are investigated. The numerical simulations are performed using both classical and quantum mechanical transport theory and we found that both approaches exhibit similar characteristic features. The effects of the Gaussian bump are manifested by a decrease of the bend resistance, R B, around zero-magnetic field and the occurrence of side-peaks in R B. These features are explained as a consequence of bump-assisted scattering of electrons towards different terminals of the Hall bar. Using these features we are able to give an estimate of the size of the bump. Additional oscillations in R B are found in the quantum description that are due to the population/depopulation of Landau levels. The bump has a minor influence on the Hall resistance even for very high values of the pseudo-magnetic field. When the bump is placed outside the center of the Hall bar valley polarized electrons can be collected in the leads.

  13. Biomechanical strain of goldsmiths.

    PubMed

    Cândido, Paula Emanuela Fernandes; Teixeira, Juliana Vieira Schmidt; Moro, Antônio Renato Pereira; Gontijo, Leila Amaral

    2012-01-01

    The work of the goldsmiths consists in the manufacture of jewelry. The piece, be it an earring, bracelet or necklace, is hand-assembled. This task requires precision, skill, kindness and patience. In this work, we make use of tools such as cuticle clippers and rounded tip, beads or precious stones and also pieces of metal. This type of activity requires a biomechanical stress of hands and wrists. In order to quantify the biomechanical stress, we performed a case study to measure the movements performed by an assembly of pieces of jewelry. As method for research, filming was done during assembly of parts to a paste, using a Nikon digital camera, for 1 (one) hour. The film was edited by Kinovea software, and the task was divided into cycles, each cycle corresponds to a complete object. In one cycle, there are four two movements of supination and pronation movements of the forearm. The cycle lasts approximately sixteen seconds, totaling 1800 cycles in eight hours. Despite the effort required of the wrists, the activity shows no complaints from the employees, but this fact does not mischaracterizes the ability of employees to acquire repetitive strain injuries and work-related musculoskeletal disorders.

  14. Characterization of Salmonella enteritidis strains.

    PubMed Central

    Poppe, C; McFadden, K A; Brouwer, A M; Demczuk, W

    1993-01-01

    A study was conducted to characterize 318 Salmonella enteritidis strains that were mainly isolated from poultry and their environment in Canada. Biotype, phagetype (PT), plasmid profile (PP), hybridization with a plasmid-derived virulence sequence probe, antibiotic resistance, outer membrane proteins (OMPs), and lipopolysaccharide (LPS) profiles were determined. Relationships of these properties to one another, and their diagnostic and pathogenic significance were assessed. Biotyping indicated that failure to ferment rhamnose was sometimes useful as a marker for epidemiologically related strains. Phagetyping was the most effective method for subdividing S. enteritidis; it distinguished 12 PTs. Phagetype 13 was occasionally associated with septicemia and mortality in chickens. The strains belonged to 15 PPs. A 36 megadalton (MDa) plasmid was found in 97% of the strains. Only the 36 MDa plasmid hybridized with the probe. Seventeen percent of the strains were drug resistant; all strains were sensitive to ciprofloxacin. Thirty-five of 36 strains possessed the same OMP profile, and 36 of 41 strains contained smooth LPS. Images Fig. 1. PMID:8358678

  15. Difference Between Strain and Sprain.

    ERIC Educational Resources Information Center

    Connors, G. Patrick

    Provided in this description of the differences between a strain (damage to the muscle or tendon) and a sprain (damage to the ligament) are definitions of mild, moderate, and severe (first, second, and third degree) strains and sprains. A final caution is given that these are two separate and distinct problems and should be treated as such. (DC)

  16. Hypothetical strain-free oligoradicals

    PubMed Central

    Hoffmann, Roald; Eisenstein, Odile; Balaban, Alexandru T.

    1980-01-01

    Several new classes of oligoradicals free of angle strain are suggested and examined by means of molecular orbital calculations. The collapse products of these hypothetical radicals are highly strained molecules. Various electronic strategies for the stabilization of these oligoradicals have been explored. PMID:16592882

  17. Strain gage system evaluation program

    NASA Technical Reports Server (NTRS)

    Dolleris, G. W.; Mazur, H. J.; Kokoszka, E., Jr.

    1978-01-01

    A program was conducted to determine the reliability of various strain gage systems when applied to rotating compressor blades in an aircraft gas turbine engine. A survey of current technology strain gage systems was conducted to provide a basis for selecting candidate systems for evaluation. Testing and evaluation was conducted in an F 100 engine. Sixty strain gage systems of seven different designs were installed on the first and third stages of an F 100 engine fan. Nineteen strain gage failures occurred during 62 hours of engine operation, for a survival rate of 68 percent. Of the failures, 16 occurred at blade-to-disk leadwire jumps (84 percent), two at a leadwire splice (11 percent), and one at a gage splice (5 percent). Effects of erosion, temperature, G-loading, and stress levels are discussed. Results of a post-test analysis of the individual components of each strain gage system are presented.

  18. Strain Insensitive Optical Phase Locked Loop

    NASA Technical Reports Server (NTRS)

    Egalon, Claudio O. (Inventor); Rogowski, Robert S. (Inventor)

    1998-01-01

    A strain sensor uses optical fibers including strain insensitive portions and a strain sensitive portion. The optical fibers form a sensitive arm of an optical phase locked loop (OPLL). The use of the OPLL allows for multimode optical fiber to be used in a strain insensitive configuration. Only strain information for the strain sensitive portion is monitored rather than the integrated strain measurements commonly made with optical fiber sensors.

  19. High temperature strain measurement with a resistance strain gage

    NASA Technical Reports Server (NTRS)

    Lei, Jih-Fen; Fichtel, ED; Mcdaniel, Amos

    1993-01-01

    A PdCr based electrical resistance strain gage was demonstrated in the laboratory to be a viable sensor candidate for static strain measurement at high temperatures. However, difficulties were encountered while transferring the sensor to field applications. This paper is therefore prepared for recognition and resolution of the problems likely to be encountered with PdCr strain gages in field applications. Errors caused by the measurement system, installation technique and lead wire attachment are discussed. The limitations and some considerations related to the temperature compensation technique used for this gage are also addressed.

  20. Recent advances in echocardiography: strain and strain rate imaging

    PubMed Central

    Mirea, Oana; Duchenne, Jurgen; Voigt, Jens-Uwe

    2016-01-01

    Deformation imaging by echocardiography is a well-established research tool which has been gaining interest from clinical cardiologists since the introduction of speckle tracking. Post-processing of echo images to analyze deformation has become readily available at the fingertips of the user. New parameters such as global longitudinal strain have been shown to provide added diagnostic value, and ongoing efforts of the imaging societies and industry aimed at harmonizing methods will improve the technique further. This review focuses on recent advances in the field of echocardiographic strain and strain rate imaging, and provides an overview on its current and potential future clinical applications. PMID:27158476

  1. Dietary supplementation of a mixture of Lactobacillus strains enhances performance of broiler chickens raised under heat stress conditions

    NASA Astrophysics Data System (ADS)

    Faseleh Jahromi, Mohammad; Wesam Altaher, Yassir; Shokryazdan, Parisa; Ebrahimi, Roohollah; Ebrahimi, Mahdi; Idrus, Zulkifli; Tufarelli, Vincenzo; Liang, Juan Boo

    2016-07-01

    High ambient temperature is a major problem in commercial broiler production in the humid tropics because high producing broiler birds consume more feed, have higher metabolic activity, and thus higher body heat production. To evaluate the effects of two previously isolated potential probiotic strains ( Lactobacillus pentosus ITA23 and Lactobacillus acidophilus ITA44) on broilers growing under heat stress condition, a total of 192 chicks were randomly allocated into four treatment groups of 48 chickens each as follows: CL, birds fed with basal diet raised in 24 °C; PL, birds fed with basal diet plus 0.1 % probiotic mixture raised in 24 °C; CH, birds fed with basal diet raised in 35 °C; and PH, birds fed with basal diet plus 0.1 % probiotic mixture raised in 35 °C. The effects of probiotic mixture on the performance, expression of nutrient absorption genes of the small intestine, volatile fatty acids (VFA) and microbial population of cecal contents, antioxidant capacity of liver, and fatty acid composition of breast muscle were investigated. Results showed that probiotic positively affected the final body weight under both temperature conditions (PL and PH groups) compared to their respective control groups (CL and CH). Probiotic supplementation numerically improved the average daily gain (ADG) under lower temperature, but significantly improved ADG under the higher temperature ( P < 0.05) by sustaining high feed intake. Under the lower temperature environment, supplementation of the two Lactobacillus strains significantly increased the expression of the four sugar transporter genes tested (GLUT2, GLUT5, SGLT1, and SGLT4) indicating probiotic enhances the absorption of this nutrient. Similar but less pronounced effect was also observed under higher temperature (35 °C) condition. In addition, the probiotic mixture improved bacterial population of the cecal contents, by increasing beneficial bacteria and decreasing Escherichia coli population, which could be

  2. Low TCR nanocomposite strain gages

    NASA Technical Reports Server (NTRS)

    Gregory, Otto J. (Inventor); Chen, Ximing (Inventor)

    2012-01-01

    A high temperature thin film strain gage sensor capable of functioning at temperatures above 1400.degree. C. The sensor contains a substrate, a nanocomposite film comprised of an indium tin oxide alloy, zinc oxide doped with alumina or other oxide semiconductor and a refractory metal selected from the group consisting of Pt, Pd, Rh, Ni, W, Ir, NiCrAlY and NiCoCrAlY deposited onto the substrate to form an active strain element. The strain element being responsive to an applied force.

  3. Virtual strain gage size study

    SciTech Connect

    Reu, Phillip L.

    2015-09-22

    DIC is a non-linear low-pass spatial filtering operation; whether we consider the effect of the subset and shape function, the strain window used in the strain calculation, of other post-processing of the results, each decision will impact the spatial resolution, of the measurement. More fundamentally, the speckle size limits, the spatial resolution by dictating the smallest possible subset. After this decision the processing settings are controlled by the allowable noise level balanced by possible bias errors created by the data filtering. This article describes a process to determine optimum DIC software settings to determine if the peak displacements or strains are being found.

  4. Radio Frequency (RF) strain monitor

    NASA Technical Reports Server (NTRS)

    Heyman, Joseph S. (Inventor); Rogowski, Robert S. (Inventor); Holben, Milford S., Jr. (Inventor)

    1988-01-01

    This invention relates to an apparatus for measuring strain in a structure. In particular, the invention detects strain in parts per million to over ten percent along an entire length (or other dimension) of a structure measuring a few millimeters to several kilometers. By using a propagation path bonded to the structure, the invention is not limited by the signal attenuation characteristics of the structure and thus frequencies in the megahertz to gigahertz range may be used to detect strain in part per million to over ten percent with high precision.

  5. Strain accumulation in quasicrystalline solids

    NASA Technical Reports Server (NTRS)

    Nori, Franco; Ronchetti, Marco; Elser, Veit

    1988-01-01

    The relaxation of two-dimensional quasicrystalline elastic networks when their constituent bonds are perturbed homogeneously is studied. Whereas ideal, quasi-periodic networks are stable against such perturbations, significant accumulations of strain in a class of disordered networks generated by a growth process are found. The grown networks are characterized by root mean square phason fluctuations which grow linearly with system size. The strain accumulation observed in these networks also grows linearly with system size. Finally, dependence of strain accumulation on cooling rate is found.

  6. Probiotic Dahi containing Lactobacillus acidophilus and Bifidobacterium bifidum modulates the formation of aberrant crypt foci, mucin-depleted foci, and cell proliferation on 1,2-dimethylhydrazine-induced colorectal carcinogenesis in Wistar rats.

    PubMed

    Mohania, Dheeraj; Kansal, Vinod K; Kruzliak, Peter; Kumari, Archana

    2014-08-01

    Aberrant crypt foci (ACF) and mucin-depleted foci (MDF) are pre-neoplastic lesions identified in the colon of carcinogen-treated rodents and in humans at high risk for colon cancer. The present study was carried out to divulge the protective potential of the probiotic Dahi containing Lactobacillus acidophilus LaVK2 and Bifidobacterium bifidum BbVK3 alone or in combination with piroxicam (PXC) on the development of early biomarkers of colorectal carcinogenesis in male Wistar rats administered 1,2-dimethylhydrazine (DMH). DMH was injected subcutaneously at the rate of 40 mg/kg body weight per animal twice a week for 2 weeks. A total of 120 male Wistar rats were randomly allocated to five groups, each group having 24 animals. The rats were fed with buffalo milk or probiotic supplement (20 grams) alone or as an adjunct with PXC in addition to a basal diet ad libitum for 32 weeks. Group I was offered buffalo milk (BM) and served as the control group. Group II was administered DMH along with BM and served as the DMH-control group; group III was administered BM-DMH-PXC, in which besides administering BM-DMH, PXC was also offered. Group IV was offered probiotic LaBb Dahi and DMH, and group V was offered both probiotic LaBb Dahi and PXC along with DMH. The rats were euthanized at the 8(th), 16(th), and 32(nd) week of the experiment and examined for development of ACF, aberrant crypts per ACF (AC/ACF), mucin-depleted foci (MDF), large MDF, and proliferating cell nuclear antigen (PCNA) labeling index. Administration of DMH in rats induced pre-neoplastic lesions (ACF and MDF) and increased the PCNA index in colorectal tissue. A significant (p<0.05) reduction in the number of ACF, AC/ACF, MDF, large MDF, and PCNA labeling index were observed in the probiotic LaBb Dahi group compared with the DMH control group. Feeding rats with LaBb Dahi or treatment with PXC diminished the initiation and progression of DMH-induced pre-neoplastic lesions and the PCNA index, and treatment with

  7. PLASTICITY AND NON-LINEAR ELASTIC STRAINS

    DTIC Science & Technology

    conditions existing in plane waves in an extended medium to give the time rate of change of stress as a function of the time rate of change of strain, the stress invariants, the total strain and the plastic strain. (Author)

  8. Magnetic Domain Strain Sensor Program

    DTIC Science & Technology

    1990-08-01

    static strain measurement at elevated temperatures. 2.2 Magnetic Strain Measurement Theory The initial work at GED investigated the Barkhausen effect...including large and small Barkhausen jumps. This is a wave propaga- tion phenomenon in which a magnetic wave velocity is measured. The wave velocity in a...theory explaining the phenomenon that deviates from the Barkhausen effect. Some basic concepts had to be examined to better understand magnetic phenomena

  9. HIGH-TEMPERATURE STRAIN GAGE,

    DTIC Science & Technology

    The patent involves a high-temperature tensometer consisting of a strain-sensitive wire grid, a connecting and insulating material, a sub-layer of...heat-resistant material, deposited on the part being investigated or on a backing by gas flame deposition, and a connector to fasten the strain...adhesion, the tension-sensitive wire grid is fastened through the sub-layer to the part being tested by the connecting and insulating material. (Author)

  10. NUTRITION OF FIVE BACTEROIDES STRAINS

    PubMed Central

    Quinto, Grace

    1962-01-01

    Quinto, Grace (University of Kentucky College of Medicine, Lexington). Nutrition of five Bacteroides strains. J. Bacteriol. 84:559–562. 1962.—Some of the nutritional requirements of five gram-negative anaerobic bacilli, including Ristella perfoetens, Zuberella clostridiformis, and three Bacteroides strains freshly isolated from clinical exudates, were investigated. A fluid maintenance medium was developed in which the three freshly isolated strains, C-4, C-7, and C-2795, grew maximally in 12 to 24 hr. The maintenance medium contained 2.0% Trypticase and Proteose Peptone, 0.5% glucose, and 0.1% sodium thioglycolate; it was adjusted to pH 7.2 and supplemented with 0.1 μg of hemin/ml. Strains C-4, C-7, and C-2795 were cultivated through 14 serial cultures in fluid maintenance medium containing 0.1 μg of hemin/ml. The most satisfactory inoculum was a 1:100 or 1:1,000 dilution of a 24-hr seed culture. All the strains except Z. clostridiformis grew serially in a defined medium. R. perfoetens required pantothenic acid, nicotinic acid, and the following amino acids: histidine, tryptophan, tyrosine, valine, phenylalanine, cystine, and probably arginine, glutamic acid, methionine, glycine, isoleucine, leucine, and lysine. The C-4, C-7, and C-2795 strains required the hemin supplement in defined medium, but not vitamins, purines, or pyrimidines. PMID:13972793

  11. Applications of strained layer superlattices

    NASA Astrophysics Data System (ADS)

    Smith, D. L.; Laurich, B. K.; Mailhiot, C.

    1990-04-01

    Because of different band edge lineups, strain conditions, and growth orientations, various strained layer superlattice (SLS) materials can exhibit qualitatively new physical behavior in their optical properties. Two examples are given of new physical behavior in SLS: strain generated electric fields in polar growth axis superlattices and strained type 2 superlattices. In SLS, large electric fields can be generated by the piezoelectric effect. The fields are largest for SLS with a (111) growth axis; they vanish for SLS with a (100) growth axis. The strain generated electric fields strongly modify the optical properties of the superlattice. Photogenerated electron-hole pairs screen the fields leading to a large nonlinear optical response. Application of an external electric field leads to a large linear electrooptical response. The absorption edge can be either red or blue shifted. Optical studies of (100), (111), and (211) oriented GaInAs/GaAs superlattices confirm the existence of the strain generated electric fields. Small band gap semiconductors are useful for making intrinsic long wavelength infrared detectors. Arbitrarily small band gaps can be reached in the type 2 superlattice InAs/GaSb. However, for band gaps less than 0.1 eV, the layer thicknesses are large and the overlap of electron and hole wavefunctions are small. Thus, the absorption coefficient is too small for useful infrared (IR) detection. Including In in the GaSb introduces strain in he InAs/GaInSb superlattice which shifts the band edges so that small band gaps can be reached in thin layer superlattices. Good absorption at long IR wavelengths is thus achieved.

  12. Magnetic susceptibility, petrofabrics and strain

    NASA Astrophysics Data System (ADS)

    Borradaile, Graham John

    1988-12-01

    Magnetic susceptibility is a non-destructive technique for quantifying the average fabric of a small sample of rock. The interpretation of the magnetic fabric is not always straightforward. However, the principal directions of the magnitude ellipsoid of susceptibility commonly show orientations consistent with the kinematic interpretations of folds, shear zones and other structural features. The directions may correspond with the orientations of strained objects or with the planar-linear mineral orientations. There will usually be multiple mineralogical sources of susceptibility, often involving silicates. If the sources are known, or if the susceptibility can be attributed to a single mineral species, it may be possible to establish a correlation between the strain ellipsoid and the susceptibility ellipsoid. This correlation will be of principal directions in many instances and occasionally there may be a weak correlation of strain magnitudes as well. In other circumstances it may be possible to establish a correlation between changes in susceptibility and the strain. Nevertheless magnetic fabric studies are not routine substitutes for strain analysis. Even where information on strain is not provided, the magnetic fabrics (and subfabrics) yield a measure of the preferred crystallographic orientation or preferred dimensional orientation of the minerals that may be integrated profitably with other petrofabric data. Experimental deformation of certain synthetic aggregates indicates that directions of magnetic susceptibility spin rapidly with advancing strain, especially where the matrix grains undergo crystal-plastic deformation. In certain experiments, simple shear appears to change the intensity of magnetic fabric more effectively than pure shear. Experiments indicate also that the initial anisotropy of a rock-like material is not easily overprinted by deformation whereas field studies are equivocal.

  13. Optical Strain Measurement System Development

    NASA Technical Reports Server (NTRS)

    Lant, C. T.

    1985-01-01

    Investigations of physical phenomena affecting the durability of SSME components require measurement systems operational in hostile environments. The need for such instrumentation caused the definition and operation of an optical strain measurement system. This optical strain measurement system based on the speckle shift method is being developed. This is a noncontact, automatic method of measuring surface strain in one dimension that corrects for error due to rigid body motion. It provides a gauge length of 1 to 2 mm and allows the region of interest on the test specimen to be mapped point by point. The output is a graphics map of the points inspected on the specimen; data points is stored in quasi-real time. This is the first phase of a multiphase effort in optical strain measurement. The speckle pattern created by the test specimen is interpreted as high order interference fringes resulting from a random diffraction grating, being the natural surface roughness of the specimen. Strain induced on the specimen causes a change in spacing of the surface roughness, which in turn shifts the position of the interference pattern (speckles).

  14. Measuring mine roof bolt strains

    DOEpatents

    Steblay, Bernard J.

    1986-01-01

    A mine roof bolt and a method of measuring the strain in mine roof bolts of this type are disclosed. According to the method, a flat portion on the head of the mine roof bolt is first machined. Next, a hole is drilled radially through the bolt at a predetermined distance from the bolt head. After installation of the mine roof bolt and loading, the strain of the mine roof bolt is measured by generating an ultrasonic pulse at the flat portion. The time of travel of the ultrasonic pulse reflected from the hole is measured. This time of travel is a function of the distance from the flat portion to the hole and increases as the bolt is loaded. Consequently, the time measurement is correlated to the strain in the bolt. Compensation for various factors affecting the travel time are also provided.

  15. Photoacoustic spectroscopy of Entamoeba histolytica strains

    NASA Astrophysics Data System (ADS)

    Acosta-Avalos, D.; Alvarado-Gil, J. J.; Silva, E. F.; Orozco, E.; de Menezes, L. F.; Vargas, H.

    2005-06-01

    Pathogenic and non-pathogenic strains of E. histolytica are studied using photoacoustic spectroscopy. It is shown that the pathogenic strain presents a spectrum similar to that of iron sulfur proteins. The non-pathogenic strain does not show any relevant absorption at the studied wavelength range. The differences observed between the optical absorption spectra of both strains opens the possibility of using photoacoustic spectroscopy as a reliable and simple technique to identify different types of E. histolytica strains.

  16. Characterization of strains of Corynebacterium bovis.

    PubMed Central

    Brooks, B W; Barnum, D A

    1984-01-01

    The biochemical and morphological characteristics of 104 strains of Corynebacterium bovis isolated from bovine milk samples and the C. bovis reference strain were found to be uniform. Valuable criteria for identification were presence of catalase and oxidase, production of acid from glucose and fructose and a requirement for enriched basal media. Six strains of human and three strains of bovine origin were found to be inconsistent with the reference strain. PMID:6722650

  17. Chronic occupational repetitive strain injury.

    PubMed Central

    O'Neil, B. A.; Forsythe, M. E.; Stanish, W. D.

    2001-01-01

    OBJECTIVE: To review common repetitive strain injuries (RSIs) that occur in the workplace, emphasizing diagnosis, treatment, and etiology of these conditions. QUALITY OF EVIDENCE: A MEDLINE search from January 1966 to June 1999 focused on articles published since 1990 because RSIs are relatively new diagnoses. MeSH headings that were explored using the thesaurus included "cumulative trauma disorder," "overuse injury," and "repetitive strain injury." The search was limited to English articles only, and preference was given to randomized controlled trials. MAIN MESSAGE: Repetitive strain injuries result from repeated stress to the body's soft tissue structures including muscles, tendons, and nerves. They often occur in patients who perform repetitive movements either in their jobs or in extracurricular activities. Common RSIs include tendon-related disorders, such as rotator cuff tendonitis, and peripheral nerve entrapment disorders, such as carpal tunnel syndrome. A careful history and physical examination often lead to the diagnosis, but newer imaging techniques, such as magnetic resonance imaging and ultrasound, can help in refractory cases. Conservative management with medication, physiotherapy, or bracing is the mainstay of treatment. Surgery is reserved for cases that do not respond to treatment. CONCLUSION: Repetitive strain injury is common; primary care physicians must establish a diagnosis and, more importantly, its relationship to occupation. Treatment can be offered by family physicians who refer to specialists for cases refractory to conservative management. PMID:11228032

  18. Trials with a Strain Gauge.

    ERIC Educational Resources Information Center

    Auty, Geoff

    1996-01-01

    Describes an attempt to match the goals of the practical demonstration of the use of a strain gauge and the technical applications of science and responding to student questions in early trials, while keeping within the level of electronics in advanced physics. (Author/JRH)

  19. Bacteriocins and novel bacterial strains.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Poultry is thought to be a significant source of Campylobacter in human disease. We evaluated anti-Campylobacter activity among 365 Bacillus and Paenibacillus isolates from poultry. One novel antagonistic Bacillus circulans and three Paenibacillus polymyxa strains were identified and further studi...

  20. Extreme Temperature Strain Measurement System

    DTIC Science & Technology

    1990-08-01

    Electrix Industries, Inc., P.O. Box 306, Lombard, IL 60148, Phone (312) 627-6802 38 Foil Strain gages. ° HiTEC Corp., Nardone Industrial Park...Planer Ltd., CERL-Planer Capacitive Transducer, Windmill Road, Sunbury -on- Thames, Middx., England, Phone: Sunbury 86262-3-4-5 • HiTEC Corp., Nardone

  1. A NEW STRAIN OF TRANSMISSIBLE LEUCEMIA IN FOWLS (STRAIN H).

    PubMed

    Ellermann, V

    1921-03-31

    1. A new strain of fowl leucosis has been transmitted through twelve generations of fowls. 2. An increase in virulence was observed during its passage. This was shown in a shortening of the interval between inoculation and death. The increase in virulence does not affect the number of successful inoculations, which remains approximately constant in from 20 to 40 per cent of the birds employed. 3. As with former strains, the disease manifests itself in various forms; i.e., myeloid and intravascular lymphoid types. A single lymphatic case was observed. 4. In several intravascular cases a diminution in the hemolytic power of the serum was established. This phenomenon was absent in a number of myeloid cases. 5. Active immunization cannot be produced by means of the subcutaneous injection of virulent material. 6. The finding of previous experiments that the virus is filterable has been confirmed. 7. The inoculation of human leucemic material into fowls gave negative results.

  2. Material mechanical characterization method for multiple strains and strain rates

    SciTech Connect

    Erdmand, III, Donald L.; Kunc, Vlastimil; Simunovic, Srdjan; Wang, Yanli

    2016-01-19

    A specimen for measuring a material under multiple strains and strain rates. The specimen including a body having first and second ends and a gage region disposed between the first and second ends, wherein the body has a central, longitudinal axis passing through the first and second ends. The gage region includes a first gage section and a second gage section, wherein the first gage section defines a first cross-sectional area that is defined by a first plane that extends through the first gage section and is perpendicular to the central, longitudinal axis. The second gage section defines a second cross-sectional area that is defined by a second plane that extends through the second gage section and is perpendicular to the central, longitudinal axis and wherein the first cross-sectional area is different in size than the second cross-sectional area.

  3. Strains

    MedlinePlus

    Pulled muscle ... can include: Pain and difficulty moving the injured muscle Discolored and bruised skin Swelling ... if you still have pain. Rest the pulled muscle for at least a day. If possible, keep ...

  4. Modelling to very high strains

    NASA Astrophysics Data System (ADS)

    Bons, P. D.; Jessell, M. W.; Griera, A.; Evans, L. A.; Wilson, C. J. L.

    2009-04-01

    Ductile strains in shear zones often reach extreme values, resulting in typical structures, such as winged porphyroclasts and several types of shear bands. The numerical simulation of the development of such structures has so far been inhibited by the low maximum strains that numerical models can normally achieve. Typical numerical models collapse at shear strains in the order of one to three. We have implemented a number of new functionalities in the numerical platform "Elle" (Jessell et al. 2001), which significantly increases the amount of strain that can be achieved and simultaneously reduces boundary effects that become increasingly disturbing at higher strain. Constant remeshing, while maintaining the polygonal phase regions, is the first step to avoid collapse of the finite-element grid required by finite-element solvers, such as Basil (Houseman et al. 2008). The second step is to apply a grain-growth routine to the boundaries of polygons that represent phase regions. This way, the development of sharp angles is avoided. A second advantage is that phase regions may merge or become separated (boudinage). Such topological changes are normally not possible in finite element deformation codes. The third step is the use of wrapping vertical model boundaries, with which optimal and unchanging model boundaries are maintained for the application of stress or velocity boundary conditions. The fourth step is to shift the model by a random amount in the vertical direction every time step. This way, the fixed horizontal boundary conditions are applied to different material points within the model every time step. Disturbing boundary effects are thus averaged out over the whole model and not localised to e.g. top and bottom of the model. Reduction of boundary effects has the additional advantage that model can be smaller and, therefore, numerically more efficient. Owing to the combination of these existing and new functionalities it is now possible to simulate the

  5. Strain tolerant microfilamentary superconducting wire

    DOEpatents

    Finnemore, Douglas K.; Miller, Theodore A.; Ostenson, Jerome E.; Schwartzkopf, Louis A.; Sanders, Steven C.

    1993-02-23

    A strain tolerant microfilamentary wire capable of carrying superconducting currents is provided comprising a plurality of discontinuous filaments formed from a high temperature superconducting material. The discontinuous filaments have a length at least several orders of magnitude greater than the filament diameter and are sufficiently strong while in an amorphous state to withstand compaction. A normal metal is interposed between and binds the discontinuous filaments to form a normal metal matrix capable of withstanding heat treatment for converting the filaments to a superconducting state. The geometry of the filaments within the normal metal matrix provides substantial filament-to-filament overlap, and the normal metal is sufficiently thin to allow supercurrent transfer between the overlapped discontinuous filaments but is also sufficiently thick to provide strain relief to the filaments.

  6. Virtual strain gage size study

    DOE PAGES

    Reu, Phillip L.

    2015-09-22

    DIC is a non-linear low-pass spatial filtering operation; whether we consider the effect of the subset and shape function, the strain window used in the strain calculation, of other post-processing of the results, each decision will impact the spatial resolution, of the measurement. More fundamentally, the speckle size limits, the spatial resolution by dictating the smallest possible subset. After this decision the processing settings are controlled by the allowable noise level balanced by possible bias errors created by the data filtering. This article describes a process to determine optimum DIC software settings to determine if the peak displacements or strainsmore » are being found.« less

  7. Strain softening in stretched DNA

    PubMed Central

    Luan, Binquan; Aksimentiev, Aleksei

    2010-01-01

    The microscopic mechanics of DNA stretching was characterized using extensive molecular dynamics simulations. By employing an anisotropic pressure control method, realistic force-extension dependences of effectively infinite DNA molecules were obtained. A coexistence of B- and S-DNA domains was observed during the overstretching transition. The simulations revealed that strain softening may occur in the process of stretching torsionally constrained DNA. The latter observation was qualitatively reconciled with available experimental data using a random-field Ising model. PMID:18851334

  8. High Temperature Capacitive Strain Gage

    NASA Technical Reports Server (NTRS)

    Wnuk, Stephen P., Jr.; Wnuk, Stephen P., III; Wnuk, V. P.

    1990-01-01

    Capacitive strain gages designed for measurements in wind tunnels to 2000 F were built and evaluated. Two design approaches were followed. One approach was based on fixed capacitor plates with a movable ground plane inserted between the plates to effect differential capacitive output with strain. The second approach was based on movable capacitor plates suspended between sapphire bearings, housed in a rugged body, and arranged to operate as a differential capacitor. A sapphire bearing gage (1/4 in. diameter x 1 in. in size) was built with a range of 50,000 and a resolution of 200 microstrain. Apparent strain on Rene' 41 was less than + or - 1000 microstrain from room temperature to 2000 F. Three gage models were built from the Ground Plane Differential concept. The first was 1/4 in. square by 1/32 in. high and useable to 700 F. The second was 1/2 in. square by 1/16 in. high and useable to 1440 F. The third, also 1/2 in. square by 1/16 in. high was expected to operate in the 1600 to 2000 F range, but was not tested because time and funding ended.

  9. High temperature capacitive strain gage

    NASA Astrophysics Data System (ADS)

    Wnuk, Stephen P., Jr.; Wnuk, Stephen P., III; Wnuk, V. P.

    1990-01-01

    Capacitive strain gages designed for measurements in wind tunnels to 2000 F were built and evaluated. Two design approaches were followed. One approach was based on fixed capacitor plates with a movable ground plane inserted between the plates to effect differential capacitive output with strain. The second approach was based on movable capacitor plates suspended between sapphire bearings, housed in a rugged body, and arranged to operate as a differential capacitor. A sapphire bearing gage (1/4 in. diameter x 1 in. in size) was built with a range of 50,000 and a resolution of 200 microstrain. Apparent strain on Rene' 41 was less than + or - 1000 microstrain from room temperature to 2000 F. Three gage models were built from the Ground Plane Differential concept. The first was 1/4 in. square by 1/32 in. high and useable to 700 F. The second was 1/2 in. square by 1/16 in. high and useable to 1440 F. The third, also 1/2 in. square by 1/16 in. high was expected to operate in the 1600 to 2000 F range, but was not tested because time and funding ended.

  10. Strain-Detecting Composite Materials

    NASA Technical Reports Server (NTRS)

    Wallace, Terryl A. (Inventor); Smith, Stephen W. (Inventor); Piascik, Robert S. (Inventor); Horne, Michael R. (Inventor); Messick, Peter L. (Inventor); Alexa, Joel A. (Inventor); Glaessgen, Edward H. (Inventor); Hailer, Benjamin T. (Inventor)

    2016-01-01

    A composite material includes a structural material and a shape-memory alloy embedded in the structural material. The shape-memory alloy changes crystallographic phase from austenite to martensite in response to a predefined critical macroscopic average strain of the composite material. In a second embodiment, the composite material includes a plurality of particles of a ferromagnetic shape-memory alloy embedded in the structural material. The ferromagnetic shape-memory alloy changes crystallographic phase from austenite to martensite and changes magnetic phase in response to the predefined critical macroscopic average strain of the composite material. A method of forming a composite material for sensing the predefined critical macroscopic average strain includes providing the shape-memory alloy having an austenite crystallographic phase, changing a size and shape of the shape-memory alloy to thereby form a plurality of particles, and combining the structural material and the particles at a temperature of from about 100-700.degree. C. to form the composite material.

  11. Strains and Sprains Are a Pain

    MedlinePlus

    ... strain at some point. Strains and sprains are common injuries, especially for kids who are very active or ... such as twisting your ankle. This kind of injury is common in sports, but also can happen any time ...

  12. Strain Monitoring of Flexible Structures

    NASA Technical Reports Server (NTRS)

    Litteken, Douglas A.

    2017-01-01

    , such as tensile testing, fatigue testing, and shear testing, but common measurement techniques cannot be used on fabric. Measuring strain in a material and during a test is a critical parameter for an engineer to monitor the structure during the test and correlate to an analytical model. The ability to measure strain in fabric structures is a challenge for NASA. Foil strain gauges, for example, are commonplace on metallic structures testing, but are extremely difficult to interface with a fabric substrate. New strain measuring techniques need to be developed for use with fabric structures. This paper investigates options for measuring strain in fabric structures for both ground testing and in-space structural health monitoring. It evaluates current commercially available options and outlines development work underway to build custom measurement solutions for NASA's fabric structures.

  13. Turbulent Plane Wakes Subjected to Successive Strains

    NASA Technical Reports Server (NTRS)

    Rogers, Michael M.

    2003-01-01

    Six direct numerical simulations of turbulent time-evolving strained plane wakes have been examined to investigate the response of a wake to successive irrotational plane strains of opposite sign. The orientation of the applied strain field has been selected so that the flow is the time-developing analogue of a spatially developing wake evolving in the presence of either a favourable or an adverse streamwise pressure gradient. The magnitude of the applied strain rate a is constant in time t until the total strain e(sup at) reaches about four. At this point, a new simulation is begun with the sign of the applied strain being reversed (the original simulation is continued as well). When the total strain is reduced back to its original value of one, yet another simulation is begun with the sign of the strain being reversed again back to its original sign. This process is done for both initially "favourable" and initially "adverse" strains, providing simulations for each of these strain types from three different initial conditions. The evolution of the wake mean velocity deficit and width is found to be very similar for all the adversely strained cases, with both measures rapidly achieving exponential growth at the rate associated with the cross-stream expansive strain e(sup at). In the "favourably" strained cases, the wake widths approach a constant and the velocity deficits ultimately decay rapidly as e(sup -2at). Although all three of these cases do exhibit the same asymptotic exponential behaviour, the time required to achieve this is longer for the cases that have been previously adversely strained (by at approx. equals 1). These simulations confirm the generality of the conclusions drawn in Rogers (2002) regarding the response of plane wakes to strain. The evolution of strained wakes is not consistent with the predictions of classical self-similar analysis; a more general equilibrium similarity solution is required to describe the results. At least for the cases

  14. Using BEEM To Probe Strains In Semiconductors

    NASA Technical Reports Server (NTRS)

    Bell, L. Douglas; Milliken, Autumn M.; Manion, Stephen J.; Kaiser, William J.

    1996-01-01

    Ballistic-electron-emission microscopy (BEEM) useful in determining strains in semiconductors under some conditions. More specifically, BEEM is variant of scanning tunneling microscopy and sensitive to electronic structure of probed material. In present approach, BEEM used to obtain data on those aspects of variations in electronic structures related to variations in strains. Then by use of mathematical modeling of relationships between electronic structures and strains, variations in strains deduced from BEEM data.

  15. Temperature-Compensating Inactive Strain Gauge

    NASA Technical Reports Server (NTRS)

    Moore, Thomas C., Sr.

    1993-01-01

    Thermal contribution to output of active gauge canceled. High-temperature strain gauges include both active gauge wires sensing strains and inactive gauge wires providing compensation for thermal contributions to gauge readings. Inactive-gauge approach to temperature compensation applicable to commercially available resistance-type strain gauges operating at temperatures up to 700 degrees F and to developmental strain gauges operating at temperatures up to 2,000 degrees F.

  16. Optical Fibers Would Sense Local Strains

    NASA Technical Reports Server (NTRS)

    Egalon, Claudio O.; Rogowski, Robert S.

    1994-01-01

    Proposed fiber-optic transducers measure local strains. Includes lead-in and lead-out lengths producing no changes in phase shifts, plus short sensing length in which phase shift is sensitive to strain. Phase shifts in single-mode fibers vary with strains. In alternative version, multiple portions of optical fiber sensitive to strains characteristic of specific vibrational mode of object. Same principle also used with two-mode fiber.

  17. Strain Rate Effects on Ultimate Strain of Copper

    DTIC Science & Technology

    1979-05-01

    34Dogbone" Specimen Used for Quasi-Static 5 and Intermediate Rate Tests 2 Schematic of Split Hopkinso’v Bar Apparatus 7 3a PETN Filled Tube Specimen...48 Experiment 25 Calculated Stress Components in Copper Cylinder 52 Expanded by PETN 26 Fracture of Explosively Expanded Cylindrical 54 Tube A-la...Record of Shot No. 10 73 A7b Framing Camera Record of Shot No. 10 74 A-8 Strain Versus Time for Copper Tube Expanded 75 by PETN vi

  18. Haemophilus ducreyi Cutaneous Ulcer Strains Are Nearly Identical to Class I Genital Ulcer Strains

    PubMed Central

    Gangaiah, Dharanesh; Webb, Kristen M.; Humphreys, Tricia L.; Fortney, Kate R.; Toh, Evelyn; Tai, Albert; Katz, Samantha S.; Pillay, Allan; Chen, Cheng-Yen; Roberts, Sally A.; Munson, Robert S.; Spinola, Stanley M.

    2015-01-01

    Background Although cutaneous ulcers (CU) in the tropics is frequently attributed to Treponema pallidum subspecies pertenue, the causative agent of yaws, Haemophilus ducreyi has emerged as a major cause of CU in yaws-endemic regions of the South Pacific islands and Africa. H. ducreyi is generally susceptible to macrolides, but CU strains persist after mass drug administration of azithromycin for yaws or trachoma. H. ducreyi also causes genital ulcers (GU) and was thought to be exclusively transmitted by microabrasions that occur during sex. In human volunteers, the GU strain 35000HP does not infect intact skin; wounds are required to initiate infection. These data led to several questions: Are CU strains a new variant of H. ducreyi or did they evolve from GU strains? Do CU strains contain additional genes that could allow them to infect intact skin? Are CU strains susceptible to azithromycin? Methodology/Principal Findings To address these questions, we performed whole-genome sequencing and antibiotic susceptibility testing of 5 CU strains obtained from Samoa and Vanuatu and 9 archived class I and class II GU strains. Except for single nucleotide polymorphisms, the CU strains were genetically almost identical to the class I strain 35000HP and had no additional genetic content. Phylogenetic analysis showed that class I and class II strains formed two separate clusters and CU strains evolved from class I strains. Class I strains diverged from class II strains ~1.95 million years ago (mya) and CU strains diverged from the class I strain 35000HP ~0.18 mya. CU and GU strains evolved under similar selection pressures. Like 35000HP, the CU strains were highly susceptible to antibiotics, including azithromycin. Conclusions/Significance These data suggest that CU strains are derivatives of class I strains that were not recognized until recently. These findings require confirmation by analysis of CU strains from other regions. PMID:26147869

  19. Antigenic differentiation of classical swine fever vaccinal strain PAV-250 from other strains, including field strains from Mexico.

    PubMed

    Mendoza, Susana; Correa-Giron, Pablo; Aguilera, Edgar; Colmenares, Germán; Torres, Oscar; Cruz, Tonatiuh; Romero, Andres; Hernandez-Baumgarten, Eliseo; Ciprián, Abel

    2007-10-10

    Twenty-nine classical swine fever virus (CSFv) strains were grown in the PK15 or SK6 cell lines. Antigenic differentiation studies were performed using monoclonal antibodies (McAbs), produced at Lelystad (CDI-DLO), The Netherlands. The monoclonals which were classified numerically as monoclonals 2-13. Epitope map patterns that resulted from the reactivity with McAbs were found to be unrelated to the pathogenicity of the viruses studied. Antigenic determinants were recognized by McAbs 5 and 8, were not detected in some Mexican strains; however, sites for McAb 6 were absent in all strains. The PAV-250 vaccine strain was recognized by all MAbs, except by MAb 6. Furthermore, the Chinese C-S vaccine strain was found to be very similar to the GPE(-) vaccine. None of the studied Mexican vaccines or field strains was found to be similar to the PAV-250 vaccine strain.

  20. Effect of strain and strain rate on residual microstructures in copper

    SciTech Connect

    Stevens, M.F.; Follansbee, P.S.

    1986-01-01

    Several specimens of OFE Cu were deformed in compression to study the resulting microstructures at equivalent levels of threshold stress and strain. Equiaxed, diffuse dislocation cells are more persistent in Cu when tested at strain rates exceeding 10/sup 3/ sec/sup -1/. At quasi-static strain rates, dislocation collapse into more distinct, narrow microbands occurs at lower strain levels.

  1. Error quantification in strain mapping methods.

    PubMed

    Guerrero, Elisa; Galindo, Pedro; Yáñez, Andrés; Ben, Teresa; Molina, Sergio I

    2007-10-01

    In this article a method for determining errors of the strain values when applying strain mapping techniques has been devised. This methodology starts with the generation of a thickness/defocus series of simulated high-resolution transmission electron microscopy images of InAsxP1-x/InP heterostructures and the application of geometric phase. To obtain optimal defocusing conditions, a comparison of different defocus values is carried out by the calculation of the strain profile standard deviations among different specimen thicknesses. Finally, based on the analogy of real state strain to a step response, a characterization of strain mapping error near an interface is proposed.

  2. Tests of strain analysis by experimental deformation

    NASA Astrophysics Data System (ADS)

    Borradaile, G. J.; McArthur, J.

    1991-01-01

    The linearisation method and Robin's method of strain analysis of granular materials yield accurate strain estimates for a variety of materials deformed experimentally in pure shear. The breakdown of continuum behaviour at high pore fluid pressures causes the methods to overestimate the strain because they do not take added rigid-body rotation into account. Both methods tolerate some variation in initial shape ratio and some degree of initial preferred orientation at modest strains. Results of tests on polymict sandstone indicate that the lower than average ductility of competent clasts may be balanced against an unfavourable degree of preferred orientation to yield an improved strain estimate.

  3. Radio-Frequency Strain Monitor

    NASA Technical Reports Server (NTRS)

    Heyman, Joseph S.; Rogowski, Robert S.; Holben, Milford S., Jr.

    1988-01-01

    Radio-frequency (RF) strain monitor developed to measure lengths of objects. RF waveguide or cable bonded to structure monitored. Propagation of RF signal along waveguide results in phase shift proportional to length of path traveled. Impedance mismatches placed in RF cable at nodes of structure. Records mismatches and detects overall length of line and lengths of intervals between nodes. Used to detect changes in elements of large structure with single cable. Monitor has potential for many applications, including monitoring stability of such large structures as aircraft, bridges, and buildings in Earthquake zones.

  4. Demonstration test of burner liner strain measurements using resistance strain gages

    NASA Technical Reports Server (NTRS)

    Grant, H. P.; Anderson, W. L.

    1984-01-01

    A demonstration test of burner liner strain measurements using resistance strain gages as well as a feasibility test of an optical speckle technique for strain measurement are presented. The strain gage results are reported. Ten Kanthal A-1 wire strain gages were used for low cycle fatigue strain measurements to 950 K and .002 apparent strain on a JT12D burner can in a high pressure (10 atmospheres) burner test. The procedure for use of the strain gages involved extensive precalibration and postcalibration to correct for cooling rate dependence, drift, and temperature effects. Results were repeatable within + or - .0002 to .0006 strain, with best results during fast decels from 950 K. The results agreed with analytical prediction based on an axisymmetric burner model, and results indicated a non-uniform circumferential distribution of axial strain, suggesting temperature streaking.

  5. Strain engineering of graphene: a review

    NASA Astrophysics Data System (ADS)

    Si, Chen; Sun, Zhimei; Liu, Feng

    2016-02-01

    Graphene has intrigued the science community by many unique properties not found in conventional materials. In particular, it is the strongest two-dimensional material ever measured, being able to sustain reversible tensile elastic strain larger than 20%, which yields an interesting possibility to tune the properties of graphene by strain and thus opens a new field called ``straintronics''. In this article, the current progress in the strain engineering of graphene is reviewed. We first summarize the strain effects on the electronic structure and Raman spectra of graphene. We then highlight the electron-phonon coupling greatly enhanced by the biaxial strain and the strong pseudomagnetic field induced by the non-uniform strain with specific distribution. Finally, the potential application of strain-engineering in the self-assembly of foreign atoms on the graphene surface is also discussed. Given the short history of graphene straintronics research, the current progress has been notable, and many further advances in this field are expected.

  6. Preliminary probiotic and technological characterization of Pediococcus pentosaceus strain KID7 and in vivo assessment of its cholesterol-lowering activity

    PubMed Central

    Damodharan, Karthiyaini; Lee, Young Sil; Palaniyandi, Sasikumar A.; Yang, Seung Hwan; Suh, Joo-Won

    2015-01-01

    The study was aimed to characterize the probiotic properties of a Pediococcus pentosaceus strain, KID7, by in vitro and in vivo studies. The strain possessed tolerance to oro-gastrointestinal transit, adherence to the Caco-2 cell line, and antimicrobial activity. KID7 exhibited bile salt hydrolase activity and cholesterol-lowering activity, in vitro. In vivo cholesterol-lowering activity of KID7 was studied using atherogenic diet-fed hypercholesterolemic mice. The experimental animals (C57BL/6J mice) were divided into 4 groups viz., normal diet-fed group (NCD), atherogenic diet-fed group (HCD), atherogenic diet- and KID7-fed group (HCD-KID7), and atherogenic diet- and Lactobacillus acidophilus ATCC 43121-fed group (HCD-L.ac) as positive control. Serum total cholesterol (T-CHO) level was significantly decreased by 19.8% in the HCD-KID7 group (P < 0.05), but not in the HCD-L.ac group compared with the HCD group. LDL cholesterol levels in both HCD-KID7 and HCD-L.ac groups were decreased by 35.5 and 38.7%, respectively, compared with HCD group (both, P < 0.05). Glutamyl pyruvic transaminase (GPT) level was significantly lower in the HCD-KID7 and HCD-L.ac groups compared to HCD group and was equivalent to that of the NCD group. Liver T-CHO levels in the HCD-KID7 group were reduced significantly compared with the HCD group (P < 0.05) but not in the HCD-L.ac group. Analysis of expression of genes associated with lipid metabolism in liver showed that low-density lipoprotein receptor (LDLR), cholesterol-7α-hydroxylase (CYP7A1) and apolipoprotein E (APOE) mRNA expression was significantly increase in the HCD-KID7 group compared to the HCD group. Furthermore, KID7 exhibited desired viability under freeze-drying and subsequent storage conditions with a combination of skim milk and galactomannan. P. pentosaceus KID7 could be a potential probiotic strain, which can be used to develop cholesterol-lowering functional food after appropriate human clinical trials. PMID:26300852

  7. Multiplicative earthquake likelihood models incorporating strain rates

    NASA Astrophysics Data System (ADS)

    Rhoades, D. A.; Christophersen, A.; Gerstenberger, M. C.

    2017-01-01

    SUMMARYWe examine the potential for <span class="hlt">strain</span>-rate variables to improve long-term earthquake likelihood models. We derive a set of multiplicative hybrid earthquake likelihood models in which cell rates in a spatially uniform baseline model are scaled using combinations of covariates derived from earthquake catalogue data, fault data, and <span class="hlt">strain</span>-rates for the New Zealand region. Three components of the <span class="hlt">strain</span> rate estimated from GPS data over the period 1991-2011 are considered: the shear, rotational and dilatational <span class="hlt">strain</span> rates. The hybrid model parameters are optimised for earthquakes of M 5 and greater over the period 1987-2006 and tested on earthquakes from the period 2012-2015, which is independent of the <span class="hlt">strain</span> rate estimates. The shear <span class="hlt">strain</span> rate is overall the most informative individual covariate, as indicated by Molchan error diagrams as well as multiplicative modelling. Most models including <span class="hlt">strain</span> rates are significantly more informative than the best models excluding <span class="hlt">strain</span> rates in both the fitting and testing period. A hybrid that combines the shear and dilatational <span class="hlt">strain</span> rates with a smoothed seismicity covariate is the most informative model in the fitting period, and a simpler model without the dilatational <span class="hlt">strain</span> rate is the most informative in the testing period. These results have implications for probabilistic seismic hazard analysis and can be used to improve the background model component of medium-term and short-term earthquake forecasting models.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25503536','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25503536"><span><span class="hlt">Strain</span> effects on oxygen migration in perovskites.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Mayeshiba, Tam; Morgan, Dane</p> <p>2015-01-28</p> <p>Fast oxygen transport materials are necessary for a range of technologies, including efficient and cost-effective solid oxide fuel cells, gas separation membranes, oxygen sensors, chemical looping devices, and memristors. <span class="hlt">Strain</span> is often proposed as a method to enhance the performance of oxygen transport materials, but the magnitude of its effect and its underlying mechanisms are not well-understood, particularly in the widely-used perovskite-structured oxygen conductors. This work reports on an ab initio prediction of <span class="hlt">strain</span> effects on migration energetics for nine perovskite systems of the form LaBO3, where B = [Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Ga]. Biaxial <span class="hlt">strain</span>, as might be easily produced in epitaxial systems, is predicted to lead to approximately linear changes in migration energy. We find that tensile biaxial <span class="hlt">strain</span> reduces the oxygen vacancy migration barrier across the systems studied by an average of 66 meV per percent <span class="hlt">strain</span> for a single selected hop, with a low of 36 and a high of 89 meV decrease in migration barrier per percent <span class="hlt">strain</span> across all systems. The estimated range for the change in migration barrier within each system is ±25 meV per percent <span class="hlt">strain</span> when considering all hops. These results suggest that <span class="hlt">strain</span> can significantly impact transport in these materials, e.g., a 2% tensile <span class="hlt">strain</span> can increase the diffusion coefficient by about three orders of magnitude at 300 K (one order of magnitude at 500 °C or 773 K) for one of the most <span class="hlt">strain</span>-responsive materials calculated here (LaCrO3). We show that a simple elasticity model, which assumes only dilative or compressive <span class="hlt">strain</span> in a cubic environment and a fixed migration volume, can qualitatively but not quantitatively model the <span class="hlt">strain</span> dependence of the migration energy, suggesting that factors not captured by continuum elasticity play a significant role in the <span class="hlt">strain</span> response.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4222745','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4222745"><span>Distribution of Nontuberculous Mycobacteria <span class="hlt">strains</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p></p> <p>2013-01-01</p> <p>Aim Mycobacteria other than tuberculosis (MOTT) cause increasingly serious infections especially in immunosuppressive patients by direct transmission from the environment or after colonization. However, identification of these species is difficult because of the cost and difficulties in defining to species level. Identification and distribution of these species can help clinician in the choice of treatment. Materials and methods A total of 90 MOTT <span class="hlt">strains</span> obtained from four different centers were included in the study. These <span class="hlt">strains</span> were identified by sequence analysis of 16S rRNA and Hsp65 genetic regions. Results Accordingly, within the 90 MOTT <span class="hlt">strains</span>, 17 different species were identified. In order of frequency, these species were M. gordonea (n = 21), M. abscessus (n = 13), M. lentiflavum (n = 9), M. fortuitum (n = 8), M. intracellulare (n = 6), M. kumamotonense (n = 6), M. neoaurum (n = 5), M. chimaera (n = 5), M. alvei (n = 5), M. peregrinum (n = 3), M. canariasense (n = 3), M. flavescens (n = 1), M. mucogenicum (n = 1), M. chelona (n = 1), M. elephantis (n = 1), M. terrae (n = 1) and M. xenopi (n = 1). Most frequently identified MOTT species according to the geographical origin were as follows: M. abscessus was the most common species either in Istanbul or Malatya regions (n = 6, n = 6, consequently). While M. kumamotonense was the most frequent species isolated from Ankara region (n = 6), M. gordonea was the most common for Samsun region (n = 14). Conclusion Our study revealed that frequency of MOTT varies depending on the number of clinical samples and that frequency of these species were affected by the newly identified species as a result of the use of novel molecular methods. In conclusion, when establishing diagnosis and treatment methods, it is important to know that infections caused by unidentified MOTT species may vary according to the regions in Turkey. The results</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26902321','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26902321"><span>Comparison of <span class="hlt">Strain</span> Rosettes and Digital Image Correlation for Measuring Vertebral Body <span class="hlt">Strain</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Gustafson, Hannah; Siegmund, Gunter; Cripton, Peter</p> <p>2016-05-01</p> <p><span class="hlt">Strain</span> gages are commonly used to measure bone <span class="hlt">strain</span>, but only provide <span class="hlt">strain</span> at a single location. Digital image correlation (DIC) is an optical technique that provides the displacement, and therefore <span class="hlt">strain</span>, over an entire region of interest on the bone surface. This study compares vertebral body <span class="hlt">strains</span> measured using <span class="hlt">strain</span> gages and DIC. The anterior surfaces of 15 cadaveric porcine vertebrae were prepared with a <span class="hlt">strain</span> rosette and a speckled paint pattern for DIC. The vertebrae were loaded in compression with a materials testing machine, and two high-resolution cameras were used to image the anterior surface of the bones. The mean noise levels for the <span class="hlt">strain</span> rosette and DIC were 1 με and 24 με, respectively. Bland-Altman analysis was used to compare <span class="hlt">strain</span> from the DIC and rosette (excluding 44% of trials with some evidence of <span class="hlt">strain</span> rosette failure or debonding); the mean difference ± 2 standard deviations (SDs) was -108 με ± 702 με for the minimum (compressive) principal <span class="hlt">strain</span> and -53 με ± 332 με for the maximum (tensile) principal <span class="hlt">strain</span>. Although the DIC has higher noise, it avoids the relatively high risk we observed of <span class="hlt">strain</span> gage debonding. These results can be used to develop guidelines for selecting a method to measure <span class="hlt">strain</span> on bone.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AIPC.1723b0001D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AIPC.1723b0001D"><span>Modeling competition between yeast <span class="hlt">strains</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>de Gee, Maarten; van Mourik, Hilda; de Visser, Arjan; Molenaar, Jaap</p> <p>2016-04-01</p> <p>We investigate toxin interference competition between S. cerevisiae colonies grown on a solid medium. In vivo experiments show that the outcome of this competition depends strongly on nutrient availability and cell densities. Here we present a new model for S. cerevisiae colonies, calculating the local height and composition of the colonies. The model simulates yeast colonies that show a good fit to experimental data. Simulations of colonies that start out with a homogeneous mixture of toxin producing and toxin sensitive cells can display remarkable pattern formation, depending on the initial ratio of the <span class="hlt">strains</span>. Simulations in which the toxin producing and toxin sensitive species start at nearby positions clearly show that toxin production is advantageous.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24518385','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24518385"><span>The many shades of prion <span class="hlt">strain</span> adaptation.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Baskakov, Ilia V</p> <p>2014-01-01</p> <p>In several recent studies transmissible prion disease was induced in animals by inoculation with recombinant prion protein amyloid fibrils produced in vitro. Serial transmission of amyloid fibrils gave rise to a new class of prion <span class="hlt">strains</span> of synthetic origin. Gradual transformation of disease phenotypes and PrP(Sc) properties was observed during serial transmission of synthetic prions, a process that resembled the phenomenon of prion <span class="hlt">strain</span> adaptation. The current article discusses the remarkable parallels between phenomena of prion <span class="hlt">strain</span> adaptation that accompanies cross-species transmission and the evolution of synthetic prions occurring within the same host. Two alternative mechanisms underlying prion <span class="hlt">strain</span> adaptation and synthetic <span class="hlt">strain</span> evolution are discussed. The current article highlights the complexity of the prion transmission barrier and <span class="hlt">strain</span> adaptation and proposes that the phenomenon of prion adaptation is more common than previously thought.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.dtic.mil/docs/citations/ADA571154','DTIC-ST'); return false;" href="http://www.dtic.mil/docs/citations/ADA571154"><span>SNIT: SNP Identification for <span class="hlt">Strain</span> Typing</span></a></p> <p><a target="_blank" href="https://publicaccess.dtic.mil/psm/api/service/search/search">DTIC Science & Technology</a></p> <p></p> <p>2011-01-01</p> <p>Durkin S, Schneewind O, Nierman WC: Genome sequencing and analysis of Yersina pestis KIM D27, an avirulent <span class="hlt">strain</span> exempt from select agent regulation. PLoS...gener- ated from next-generation sequencing (NGS) data, we selected the recently published Yersinia pestis KIM D27 genome [12]. The Y. pestis D27 <span class="hlt">strain</span>...is a deriva- tive of Y. pestis KIM 10 <span class="hlt">strain</span> (accession no. NC_004088). The Y. pestis KIM D27 draft genome (accession no. ADDC00000000) was generated</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19840000339&hterms=vibrational+modes&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dvibrational%2Bmodes','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19840000339&hterms=vibrational+modes&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dvibrational%2Bmodes"><span>Deriving <span class="hlt">Strain</span> Modes From Vibrational Tests</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Young, J. W.; Joanides, J. C.</p> <p>1985-01-01</p> <p>Measurements and theoretical analysis complement each other. Experimental acceleration and <span class="hlt">strain</span> data used to calculate coefficients of low-frequency vibrational modes of object under test. An iterative comparison of experimental and calculated <span class="hlt">strains</span> give modal model of improved accuracy that predicts <span class="hlt">strains</span> under operating conditions. Method useful in fatigue life and reliability analyses of buildings, pumps, engines, vehicles, and other systems subject to vibrations and loud noises during operation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5074739','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=5074739"><span>A multi-<span class="hlt">strain</span> Synbiotic may reduce viral respiratory infections in asthmatic children: a randomized controlled trial</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Ahanchian, Hamid; Jafari, Seyed Ali; Ansari, Elham; Ganji, Toktam; Kiani, Mohammad Ali; Khalesi, Maryam; Momen, Tooba; Kianifar, Hamidreza</p> <p>2016-01-01</p> <p>Background and objective Asthma is a growing problem worldwide. Acute exacerbations impose considerable morbidity, mortality, and increased cost. Viral respiratory infections are the most common cause (80–85%) of pediatric asthma exacerbations and admissions to the hospital. The aim of this study was to determine the effect of a new synbiotic Lactocare® on viral respiratory infections and asthma exacerbations in asthmatic children. Methods In this double blind, placebo-controlled, randomized clinical trial, 72 children with mild persistent asthma, aged between 6 and 12 years, were randomized to receive either Lactocare®, a Synbiotic containing 1 billion CFU/Capsule of Lactobacillus casei, Lactobacillus rhamnosus, Streptococcus thermophilus, Bifidobacterium breve, Lactobacillus <span class="hlt">acidophilus</span>, Bifidobacterium infantis, Lactobacillus bulgaricus, and Fructooligosacharide (Zist Takhmir, Tehran, Iran) or placebo daily for 60 days. The primary outcome was the number of viral respiratory infections, and secondary outcomes were school absence, salbutamol and prednisolone usage, outpatient visits, and hospital admission for asthma. The outcomes were compared among study groups using the SPSS 11.5 program and the Mann Whitney and Fisher exact tests. Results Of the 72 children who were enrolled with mild persistent asthma, 36 were assigned randomly to be treated with synbiotic and 36 with placebo. The number of viral respiratory infections was significantly higher in placebo group than the synbiotic group during the first month of intervention (0.74 ± 0.12 vs. 0.44 ± 0.1, p < 0.007) but not during the second month (0.5 ± 0.8 vs. 0.5 ± 0.8, p < 0.641). Considering the total duration of the study (two months), infection episodes also were significantly lower in the synbiotic group (0.92 ± 0.15 vs. 0.69 ± 0.11, p < 0.046). Salbutamol consumption was significantly lower in the synbiotic group, but there were no significant differences in school absenteeism, oral</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016MsT.........54S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016MsT.........54S"><span>Construction of an Optical Fiber <span class="hlt">Strain</span> Gauge</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sulaiman, Najwa</p> <p></p> <p>This project is focused on the construction of an optical fiber <span class="hlt">strain</span> gauge that is based on a <span class="hlt">strain</span> gauge described by Butter and Hocker. Our gauge is designed to generate an interference pattern from the signals carried on two bare single-mode fibers that are fastened to an aluminum cantilever. When the cantilever experiences flexural stress, the interference pattern should change. By observing this change, it is possible to determine the <span class="hlt">strain</span> experienced by the cantilever. I describe the design and construction of our optical fiber <span class="hlt">strain</span> gauge as well as the characterization of different parts of the apparatus.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/912475','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/912475"><span>Measurement of Sorption-Induced <span class="hlt">Strain</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Eric P. Robertson; Richard L. Christiansen</p> <p>2005-05-01</p> <p><span class="hlt">Strain</span> caused by the adsorption of gases was measured in samples of subbituminous coal from the Powder River basin of Wyoming, U.S.A. and high-volatile bituminous coal from east-central Utah, U.S.A. using an apparatus developed jointly at the Idaho National Laboratory (Idaho Falls, Idaho, U.S.A.) and Colorado School of Mines (Golden, Colorado, U.S.A.). The apparatus can be used to measure <span class="hlt">strain</span> on multiple small coal samples based on the optical detection of the longitudinal <span class="hlt">strain</span> instead of the more common usage of <span class="hlt">strain</span> gauges, which require larger samples and longer equilibration times. With this apparatus, we showed that the swelling and shrinkage processes were reversible and that accurate <span class="hlt">strain</span> data could be obtained in a shortened amount of time. A suite of <span class="hlt">strain</span> curves was generated for these coals using gases that included carbon dioxide, nitrogen, methane, helium, and various mixtures of these gases. A Langmuir-type equation was applied to satisfactorily model the <span class="hlt">strain</span> data obtained for pure gases. The sorption-induced <span class="hlt">strain</span> measured in the subbituminous coal was larger than the high-volatile bituminous coal for all gases tested over the range of pressures used in the experimentation, with the CO2-induced <span class="hlt">strain</span> for the subbituminous coal over twice as great at the bituminous coal.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20160000697','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20160000697"><span>Acceleration and Velocity Sensing from Measured <span class="hlt">Strain</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Pak, Chan-Gi; Truax, Roger</p> <p>2016-01-01</p> <p>A simple approach for computing acceleration and velocity of a structure from the <span class="hlt">strain</span> is proposed in this study. First, deflection and slope of the structure are computed from the <span class="hlt">strain</span> using a two-step theory. Frequencies of the structure are computed from the time histories of <span class="hlt">strain</span> using a parameter estimation technique together with an Autoregressive Moving Average model. From deflection, slope, and frequencies of the structure, acceleration and velocity of the structure can be obtained using the proposed approach. shape sensing, fiber optic <span class="hlt">strain</span> sensor, system equivalent reduction and expansion process.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/20976649','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/20976649"><span><span class="hlt">Strain</span> accommodation in inelastic deformation of glasses</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Murali, P.; Ramamurty, U.; Shenoy, Vijay B.</p> <p>2007-01-01</p> <p>Motivated by recent experiments on metallic glasses, we examine the micromechanisms of <span class="hlt">strain</span> accommodation including crystallization and void formation during inelastic deformation of glasses by employing molecular statics simulations. Our atomistic simulations with Lennard-Jones-like potentials suggests that a softer short range interaction between atoms favors crystallization. Compressive hydrostatic <span class="hlt">strain</span> in the presence of a shear <span class="hlt">strain</span> promotes crystallization whereas a tensile hydrostatic <span class="hlt">strain</span> is found to induce voids. The deformation subsequent to the onset of crystallization includes partial reamorphization and recrystallization, suggesting important atomistic mechanisms of plastic dissipation in glasses.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/366503','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/366503"><span>Investigation of a noncontact <span class="hlt">strain</span> measurement technique</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Damiano, B.; Talarico, L.J.</p> <p>1996-05-01</p> <p>The goal of this project was to investigate the feasibility of a new noncontact technique for directly and continuously monitoring peak <span class="hlt">strain</span> in rotating components. The technique utilizes the unique <span class="hlt">strain</span>-sensitive magnetic material properties of transformation Induced Plasticity (TRIP) steel alloys to measure <span class="hlt">strain</span>. These alloys are weakly magnetic when unstrained but become strongly ferromagnetic after mechanical deformation. A computer study was performed to determine whether the <span class="hlt">strain</span>-induced change in the magnetic material properties of a TRIP steel gage bonded to a rotating component would cause significant perturbations in the magnetic flux of a stationary electromagnet. The effects of <span class="hlt">strain</span> level, distance between the rotating component and the stationary electromagnet, and motion-induced eddy currents on flux perturbation magnitude were investigated. The calculated results indicate that a TRIP steel <span class="hlt">strain</span> sensing element can cause a significant perturbation in the magnetic flux of a stationary electromagnet. The magnetic flux perturbation magnitude was found to be inversely proportional to the distance between the magnet face and the TRIP steel element and directly proportional to the TRIP steel <span class="hlt">strain</span> level. The effect of motion-induced eddy currents on the magnetic flux was found to be negligible. It appears that the technique can be successfully applied to measure peak <span class="hlt">strain</span> in rotating components; however, the sensitivity of the magnetic flux perturbation magnitude to the distance between the <span class="hlt">strain</span> sensing element and the electromagnet may require making an independent proximity measurement.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_19 --> <div id="page_20" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="381"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/7453585','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/7453585"><span>[Antigenic relationships between Debaryomyces <span class="hlt">strains</span> (author's transl)].</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Aksoycan, N</p> <p>1980-01-01</p> <p>The results of the agglutinations between homologous and heterologous Debaryomyces <span class="hlt">strains</span> and their agglutinating sera are shown in table I. According to these findings, D. hansenii and D. marama are antigenically different from other Debaryomyces <span class="hlt">strains</span> in this genus. In a previous study Aksoycan et al. have shown a common antigenic factor between D. hansenii, D. marama <span class="hlt">strains</span> and Salmonella 0:7 antigen. This factor was not present in other six <span class="hlt">strains</span> of Debaryomyces. These results also show that D. tamarii does not have any antigenic relationship with the other seven species of Debaryomyces in this genus.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012APS..MARV27001L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012APS..MARV27001L"><span>Making Novel Materials Using <span class="hlt">Strain</span> in Nanomembranes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lagally, Max G.</p> <p>2012-02-01</p> <p>The controlled introduction of <span class="hlt">strain</span> in materials offers an important degree of freedom for fundamental studies of materials as well as advanced device engineering. <span class="hlt">Strain</span> in a crystalline solid modifies the lattice constants and reduces the crystal symmetry. Because <span class="hlt">strain</span> energy is proportional to thickness, a free-standing crystalline thin sheet, which we call a nanomembrane (NM), can be <span class="hlt">strained</span> to a greater degree that a bulk material with the same surface area. I show the use of nanomembrane <span class="hlt">strain</span> engineering to make defect-free single crystals that cannot be grown any other way, and materials with <span class="hlt">strain</span> symmetries that they do not have naturally, in both cases alloys of Si and Ge. <span class="hlt">Strain</span> in NMs causes significant shifts in energy band edges, splitting of degenerate states, and changes in effective masses. These effects can be used to produce a desired band offset between different materials, to increase carrier mobility, and to change relative energy positions of valleys. In the latter respect, through the use of NMs it has recently become possible, using tensile <span class="hlt">strain</span>, to make Ge direct-bandgap and light emitting at room temperature. Periodic local stress can produce <span class="hlt">strain</span> superlattices and thus single-element heterojunctions. Work performed with the Roberto Paiella, Mark Eriksson, Feng Liu, and Irena Knezevic research groups.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/867015','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/servlets/purl/867015"><span>Optical fiber sensor technique for <span class="hlt">strain</span> measurement</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Butler, Michael A.; Ginley, David S.</p> <p>1989-01-01</p> <p>Laser light from a common source is split and conveyed through two similar optical fibers and emitted at their respective ends to form an interference pattern, one of the optical fibers having a portion thereof subjected to a <span class="hlt">strain</span>. Changes in the <span class="hlt">strain</span> cause changes in the optical path length of the <span class="hlt">strain</span> fiber, and generate corresponding changes in the interference pattern. The interference pattern is received and transduced into signals representative of fringe shifts corresponding to changes in the <span class="hlt">strain</span> experienced by the <span class="hlt">strained</span> one of the optical fibers. These signals are then processed to evaluate <span class="hlt">strain</span> as a function of time, typical examples of the application of the apparatus including electrodeposition of a metallic film on a conductive surface provided on the outside of the optical fiber being <span class="hlt">strained</span>, so that <span class="hlt">strains</span> generated in the optical fiber during the course of the electrodeposition are measurable as a function of time. In one aspect of the invention, signals relating to the fringe shift are stored for subsequent processing and analysis, whereas in another aspect of the invention the signals are processed for real-time display of the <span class="hlt">strain</span> changes under study.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AcMSn..29..543X','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AcMSn..29..543X"><span>Control of surface wettability via <span class="hlt">strain</span> engineering</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Xiong, Wei; Liu, Jefferson Zhe; Zhang, Zhi-Liang; Zhen, Quan-Shui</p> <p>2013-08-01</p> <p>Reversible control of surface wettability has wide applications in lab-on-chip systems, tunable optical lenses, and microfluidic tools. Using a graphene sheet as a sample material and molecular dynamic simulations, we demonstrate that <span class="hlt">strain</span> engineering can serve as an effective way to control the surface wettability. The contact angles θ of water droplets on a graphene vary from 72.5° to 106° under biaxial <span class="hlt">strains</span> ranging from -10% to 10% that are applied on the graphene layer. For an intrinsic hydrophilic surface (at zero <span class="hlt">strain</span>), the variation of θ upon the applied <span class="hlt">strains</span> is more sensitive, i.e., from 0° to 74.8°. Overall the cosines of the contact angles exhibit a linear relation with respect to the <span class="hlt">strains</span>. In light of the inherent dependence of the contact angle on liquid-solid interfacial energy, we develop an analytic model to show the cos θ as a linear function of the adsorption energy E ads of a single water molecule over the substrate surface. This model agrees with our molecular dynamic results very well. Together with the linear dependence of E ads on biaxial <span class="hlt">strains</span>, we can thus understand the effect of <span class="hlt">strains</span> on the surface wettability. Thanks to the ease of reversibly applying mechanical <span class="hlt">strains</span> in micro/nano-electromechanical systems, we believe that <span class="hlt">strain</span> engineering can be a promising means to achieve the reversibly control of surface wettability.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19840004375','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19840004375"><span>Inflatable device for installing <span class="hlt">strain</span> gage bridges</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Cook, C. E.; Smith, G. E.; Monaghan, R. C. (Inventor)</p> <p>1983-01-01</p> <p>Methods and devices for installing in a tubular shaft multiple <span class="hlt">strain</span> gages are disclosed with focus on a method and a device for pneumatically forcing <span class="hlt">strain</span> gages into seated engagement with the internal surfaces of a tubular shaft in an installation of multiple <span class="hlt">strain</span> gages in a tubular shaft. The <span class="hlt">strain</span> gages or other electron devices are seated in a template-like component which is wrapped about a pneumatically expansible body. The component is inserted into a shaft and the body is pneumatically expanded after a suitable adhesive was applied to the surfaces.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002SPIE.4700..304A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002SPIE.4700..304A"><span>Microminiature temperature-compensated magnetoelastic <span class="hlt">strain</span> gauge</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Arms, Steven W.; Townsend, Christopher P.</p> <p>2002-07-01</p> <p>Our objective was to demonstrate a microminiature magnetoelastic <span class="hlt">strain</span> gauge that provides both <span class="hlt">strain</span> and temperature signals without additional sensors. Iron based magnetoelastic materials were embedded within superelastic nickel/titanium (NiTi) tubing. NiTi stress was transferred to the ferrite, causing a permeability change sensed by a tiny coil. The coil/bridge was excited (70 KHz AC), synchronously demodulated, and amplified to produce a voltage output proportional to coil/ferrite impedance. A DC voltage was also applied and separately conditioned to provide an output proportional to coil resistance; this signal was used to provide thermal compensation. Controlled <span class="hlt">strains</span> were applied and 6 Hz cyclic outputs recorded simultaneously from the magnetoelastic <span class="hlt">strain</span> gauge and conventional foil <span class="hlt">strain</span> gauges. The magnetoelastic <span class="hlt">strain</span> gauge tracked the foil gauge with minimal hysteresis and good linearity over 600 microstrain; repeatability was approximately 1.5 microstrain. The magnetoelastic <span class="hlt">strain</span> gauge's gauge factor was computed from delta inductance/original inductance under static <span class="hlt">strain</span> conditions. Temperatures of 25-140 deg C resulted in an uncompensated shift of 15 microstrain/deg C, and compensated shift of 1.0 microstrain/deg C. A sensitive micro-magnetoelastic <span class="hlt">strain</span> gauge was demonstrated using the same sensor to detect stress and temperature with no moving parts, high gauge factor, and good thermal stability.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014SPIE.9061E..31R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014SPIE.9061E..31R"><span>Distributed <span class="hlt">strain</span> monitoring for bridges: temperature effects</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Regier, Ryan; Hoult, Neil A.</p> <p>2014-03-01</p> <p>To better manage infrastructure assets as they reach the end of their service lives, quantitative data is required to better assess structural behavior and allow for more informed decision making. Distributed fiber optic <span class="hlt">strain</span> sensors are one sensing technology that could provide comprehensive data for use in structural assessments as these systems potentially allow for <span class="hlt">strain</span> to be measured with the same accuracy and gage lengths as conventional <span class="hlt">strain</span> sensors. However, as with many sensor technologies, temperature can play an important role in terms of both the structure's and sensor's performance. To investigate this issue a fiber optic distributed <span class="hlt">strain</span> sensor system was installed on a section of a two span reinforced concrete bridge on the TransCanada Highway. <span class="hlt">Strain</span> data was acquired several times a day as well as over the course of several months to explore the effects of changing temperature on the data. The results show that the <span class="hlt">strain</span> measurements are affected by the bridge behavior as a whole. The <span class="hlt">strain</span> measurements due to temperature are compared to <span class="hlt">strain</span> measurements that were taken during a load test on the bridge. The results show that even a small change in temperature can produce crack width and <span class="hlt">strain</span> changes similar to those due to a fully loaded transport truck. Future directions for research in this area are outlined.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4644690','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4644690"><span>Skeletal muscle tensile <span class="hlt">strain</span> dependence: hyperviscoelastic nonlinearity</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Wheatley, Benjamin B; Morrow, Duane A; Odegard, Gregory M; Kaufman, Kenton R; Donahue, Tammy L Haut</p> <p>2015-01-01</p> <p>Introduction Computational modeling of skeletal muscle requires characterization at the tissue level. While most skeletal muscle studies focus on hyperelasticity, the goal of this study was to examine and model the nonlinear behavior of both time-independent and time-dependent properties of skeletal muscle as a function of <span class="hlt">strain</span>. Materials and Methods Nine tibialis anterior muscles from New Zealand White rabbits were subject to five consecutive stress relaxation cycles of roughly 3% <span class="hlt">strain</span>. Individual relaxation steps were fit with a three-term linear Prony series. Prony series coefficients and relaxation ratio were assessed for <span class="hlt">strain</span> dependence using a general linear statistical model. A fully nonlinear constitutive model was employed to capture the <span class="hlt">strain</span> dependence of both the viscoelastic and instantaneous components. Results Instantaneous modulus (p<0.0005) and mid-range relaxation (p<0.0005) increased significantly with <span class="hlt">strain</span> level, while relaxation at longer time periods decreased with <span class="hlt">strain</span> (p<0.0005). Time constants and overall relaxation ratio did not change with <span class="hlt">strain</span> level (p>0.1). Additionally, the fully nonlinear hyperviscoelastic constitutive model provided an excellent fit to experimental data, while other models which included linear components failed to capture muscle function as accurately. Conclusions Material properties of skeletal muscle are <span class="hlt">strain</span>-dependent at the tissue level. This <span class="hlt">strain</span> dependence can be included in computational models of skeletal muscle performance with a fully nonlinear hyperviscoelastic model. PMID:26409235</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2951977','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2951977"><span>Prion <span class="hlt">strain</span> interactions are highly selective</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Nilsson, K. Peter R.; Joshi-Barr, Shivanjali; Winson, Olivia; Sigurdson, Christina J.</p> <p>2010-01-01</p> <p>Various misfolded and aggregated neuronal proteins commonly co-exist in neurodegenerative disease, but whether the proteins co-aggregate and alter the disease pathogenesis is unclear. Here we used mixtures of distinct prion <span class="hlt">strains</span>, which are believed to differ in conformation, to test the hypothesis that two different aggregates interact and change the disease in vivo. We tracked two prion <span class="hlt">strains</span> in mice histopathologically and biochemically, as well as by spectral analysis of plaque-bound polythiophene acetic acid (PTAA), a conformation-sensitive fluorescent amyloid ligand. We found that prion <span class="hlt">strains</span> interacted in a highly selective and <span class="hlt">strain</span>-specific manner, with either (i) no interaction, (ii) hybrid plaque formation, or (iii) blockage of one <span class="hlt">strain</span> by a second (interference). The hybrid plaques were maintained upon further passage in vivo and each <span class="hlt">strain</span> seemed to maintain its original conformational properties, suggesting that one <span class="hlt">strain</span> served only as a scaffold for aggregation of the second <span class="hlt">strain</span>. These findings not only further our understanding of prion <span class="hlt">strain</span> interactions, but also directly demonstrate interactions that may occur in other protein aggregate mixtures. PMID:20826672</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/9749560','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/9749560"><span><span class="hlt">Strain</span> amplification in the bone mechanosensory system.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Cowin, S C; Weinbaum, S</p> <p>1998-09-01</p> <p>This article discusses the potential mechanisms by which the <span class="hlt">strain</span> induced at the membrane of an osteocyte may be amplified from the <span class="hlt">strain</span> experienced by the whole bone due to mechanical loading. These mechanisms address the question of how these mechanical load-induced small <span class="hlt">strains</span> of (typically) about 0.1% (but up to 0.5%) applied to a whole bone are amplified to <span class="hlt">strains</span> of 1% or larger at the membrane of the osteocyte buried in its lacuna in the bone matrix. The answer to this question is an important link in the mechanosensory system in bone and in relating in vitro cell studies to in vivo cellular response.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/10878089','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/10878089"><span>Surveillance of rotavirus <span class="hlt">strains</span> in the United States: identification of unusual <span class="hlt">strains</span>. The National Rotavirus <span class="hlt">Strain</span> Surveillance System collaborating laboratories.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Griffin, D D; Kirkwood, C D; Parashar, U D; Woods, P A; Bresee, J S; Glass, R I; Gentsch, J R</p> <p>2000-07-01</p> <p>Rotavirus <span class="hlt">strains</span> from 964 fecal specimens collected from children at 11 U.S. hospital laboratories from November 1997 to March 1998 and from samples collected at 12 laboratories from November 1998 to March 1999 were typed for G and P proteins. Serotype G1 was the predominant serotype in 1997-1998 (88%), followed by G2 (6.2%), G9 (3.3%), and G3 (1.5%). This pattern was similar to that seen in 1998-1999: G1 (79%), G2 (15%), G9 (3.0%), G4 (1.6%), and G3 (0.3%). Novel P[9] <span class="hlt">strains</span> were identified in both seasons, and analysis of a 364-nucleotide fragment from gene segment 4 of one of the <span class="hlt">strains</span> demonstrated 97.3% nucleotide identity with the prototype P3[9],G3 <span class="hlt">strain</span>, AU1, isolated in Japan. This is the first report of a human AU1-like <span class="hlt">strain</span> in the United States. These results reinforce our initial findings that serotype G9 persists in the United States but has not become a predominant <span class="hlt">strain</span> and that the common serotypes G1 to G4 account for almost 90% of <span class="hlt">strains</span> in circulation. Other uncommon <span class="hlt">strains</span> exist in the United States but may have been overlooked before because of their low prevalence and the use of inadequate diagnostic tools.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19950047316&hterms=seismic&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dseismic','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19950047316&hterms=seismic&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dseismic"><span>A comparison of eastern North American seismic <span class="hlt">strain</span>-rates to glacial rebound <span class="hlt">strain</span>-rates</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>James, Thomas S.; Bent, Allison L.</p> <p>1994-01-01</p> <p>Glacial rebound <span class="hlt">strain</span>-rates computed using a simple Laurentide glacial loading model are of the order of 10(exp -9) per year within the region of glaciation and extending several hundred kilometers beyond. The horizontal <span class="hlt">strain</span>-rates receive approximately equal contributions from horizontal and vertical velocities, a consequence of the spherical geometry adopted for the Earth model. In the eastern United States and southeastern Canada the computed <span class="hlt">strain</span>-rates are 1-3 orders of magnitude greater than an estimate of the average seismic <span class="hlt">strain</span>-rate (Anderson, 1986) and approximately 1 order of magnitude greater than predicted erosional <span class="hlt">strain</span>-rates. The predicted glacial rebound <span class="hlt">strain</span>-rates are not, in general, oriented in such a way as to augment the observed state of deviatoric stress, possibly explaining why the seismic <span class="hlt">strain</span>-rates are much smaller than the glacial rebound <span class="hlt">strain</span>-rates. An exception to this may be seismically active regions in the St. Lawrence valley.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016IJN....1560005S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016IJN....1560005S"><span>Simulation and Analysis of <span class="hlt">Strain</span> Sensitivity of CNT-Based <span class="hlt">Strain</span> Sensors</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sapra, Gaurav; Vig, Renu; Sharma, Manu</p> <p>2016-10-01</p> <p>Carbon nanotubes (CNT) is turning out to be a replacement to all the existing traditional sensors due to their high gauge factor, multidirectional sensing capability, high flexibility, low mass density, high dynamic range and high sensitivity to <span class="hlt">strains</span> at nano and macro- scales. The <span class="hlt">strain</span> sensitivity of CNT-based <span class="hlt">strain</span> sensors depends on number of parameters; quality and quantity of CNT used, type of polymer used, deposition and dispersion technique adopted and also on environmental conditions. Due to all these parameters, the piezoresistive behavior of CNT is diversified and it needs to be explored. This paper theoretically analyses the <span class="hlt">strain</span> sensitivity of CNT-based <span class="hlt">strain</span> sensors. The <span class="hlt">strain</span> sensitivity response of CNT <span class="hlt">strain</span> sensor is a result of change in total resistance of CNT network with respect to applied <span class="hlt">strain</span>. The total resistance of CNT network consists of intrinsic resistance and inter-tube resistance. It has been found that the change in intrinsic resistance under <span class="hlt">strain</span> is due to the variation of bandgap of individual, which depends on the chirality of the tube and it varies exponentially with <span class="hlt">strain</span>. The inter-tube resistance of CNT network changes nonlinearly due to change in distance between neighboring CNTs with respect to applied <span class="hlt">strain</span>. As the distance d between CNTs increases due to applied <span class="hlt">strain</span>, tunneling resistance Rtunnel increases nonlinearly in exponential manner. When the concentration of CNTs in composite is close to percolation threshold, then the change of inter-tube resistances is more dominant than intrinsic resistance. At percolation threshold, the total resistance of CNT networks changes nonlinearly and this effect of nonlinearity is due to tunneling effect. The <span class="hlt">strain</span> sensitivity of CNT-based <span class="hlt">strain</span> sensors also varies nonlinearly with the change in temperature. For the change of temperature from -20∘C to 50∘C, there is more than 100% change in <span class="hlt">strain</span> sensitivity of CNT/polymer composite <span class="hlt">strain</span> sensor. This change is</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/495681','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/495681"><span>Bicrystals with <span class="hlt">strain</span> gradient effects</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Shu, J.Y.</p> <p>1997-01-09</p> <p>Boundary between two perfectly bonded single crystals plays an important role in determining the deformation of the bicrystals. This work addresses the role of the grain boundary by considering the elevated hardening of a slip system due to a slip gradient. The slip gradients are associated with geometrically necessary dislocations and their effects become pronounced when a representative length scale of the deformation field is comparable to the dominant microstructural length scale of a material. A new rate-dependent crystal plasticity theory is presented and has been implemented within the finite element method framework. A planar bicrystal under uniform in-plane loading is studied using the new crystal theory. The <span class="hlt">strain</span> is found to be continuous but nonuniform within a boundary layer around the interface. The lattice rotation is also nonuniform within the boundary layer. The width of the layer is determined by the misorientation of the grains, the hardening of slip systems, and most importantly by the characteristic material length scales. The overall yield strength of the bicrystal is also obtained. A significant grain-size dependence of the yield strength, the Hall- Petch effect is predicted.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=punishment+AND+child&pg=7&id=EJ808655','ERIC'); return false;" href="http://eric.ed.gov/?q=punishment+AND+child&pg=7&id=EJ808655"><span>General <span class="hlt">Strain</span> Theory and Delinquency: Focusing on the Influences of Key <span class="hlt">Strain</span> Characteristics on Delinquency</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Moon, Byongook; Blurton, David; McCluskey, John D.</p> <p>2008-01-01</p> <p>The study examines the effects of recent, older, and chronic <span class="hlt">strains</span> and of perceived injustice of <span class="hlt">strain</span> on delinquency, sampling 777 Korean youth. Seven key <span class="hlt">strains</span> most likely leading to delinquency, some of which were often overlooked in previous research, were included, and these are family conflict, parental punishment, teachers' punishment,…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AIPC.1426..167J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AIPC.1426..167J"><span>High <span class="hlt">strain</span> rate behavior of polyurea compositions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Joshi, Vasant S.; Milby, Christopher</p> <p>2012-03-01</p> <p>High-<span class="hlt">strain</span>-rate response of three polyurea compositions with varying molecular weights has been investigated using a Split Hopkinson Pressure Bar arrangement equipped with aluminum bars. Three polyurea compositions were synthesized from polyamines (Versalink, Air Products) with a multi-functional isocyanate (Isonate 143L, Dow Chemical). Amines with molecular weights of 1000, 650, and a blend of 250/1000 have been used in the current investigation. These materials have been tested to <span class="hlt">strain</span> rates of over 6000/s. High <span class="hlt">strain</span> rate results from these tests have shown varying trends as a function of increasing <span class="hlt">strain</span>. While higher molecular weight composition show lower yield, they do not show dominant hardening behavior at lower <span class="hlt">strain</span>. On the other hand, the blend of 250/1000 show higher load bearing capability but lower <span class="hlt">strain</span> hardening effects than the 600 and 1000 molecular weight amine based materials. Results indicate that the initial increase in the modulus of the blend of 250/1000 may lead to the loss of <span class="hlt">strain</span> hardening characteristics as the material is compressed to 50% <span class="hlt">strain</span>, compared to 1000 molecular weight amine based material.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20090011203','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20090011203"><span>Nanocomposite <span class="hlt">Strain</span> Gauges Having Small TCRs</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Gregory, Otto; Chen, Ximing</p> <p>2009-01-01</p> <p>Ceramic <span class="hlt">strain</span> gauges in which the <span class="hlt">strain</span>-sensitive electrically conductive strips made from nanocomposites of noble metal and indium tin oxide (ITO) are being developed for use in gas turbine engines and other power-generation systems in which gas temperatures can exceed 1,500 F (about 816 C). In general, <span class="hlt">strain</span> gauges exhibit spurious thermally induced components of response denoted apparent <span class="hlt">strain</span>. When temperature varies, a <span class="hlt">strain</span>-gauge material that has a nonzero temperature coefficient of resistance (TCR) exhibits an undesired change in electrical resistance that can be mistaken for the change in resistance caused by a change in <span class="hlt">strain</span>. It would be desirable to formulate straingauge materials having TCRs as small as possible so as to minimize apparent <span class="hlt">strain</span>. Most metals exhibit positive TCRs, while most semiconductors, including ITO, exhibit negative TCRs. The present development is based on the idea of using the negative TCR of ITO to counter the positive TCRs of noble metals and of obtaining the benefit of the ability of both ITO and noble metals to endure high temperatures. The noble metal used in this development thus far has been platinum. Combinatorial libraries of many ceramic <span class="hlt">strain</span> gauges containing nanocomposites of various proportions of ITO and platinum were fabricated by reactive co-sputtering from ITO and platinum targets onto alumina- and zirconia-based substrates mounted at various positions between the targets.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19810000068&hterms=phase+locked+loop&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dphase%2Blocked%2Bloop','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19810000068&hterms=phase+locked+loop&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dphase%2Blocked%2Bloop"><span>Pulsed Phase-Locked-Loop <span class="hlt">Strain</span> Monitor</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Heyman, J. S.; Stone, F. D.</p> <p>1982-01-01</p> <p>P2sup.L2sup. <span class="hlt">strain</span> monitor measures <span class="hlt">strain</span> by monitoring change in phase of acoustic signal that passes through stressed sample. Phase sample causes shift in frequency of VCO. As with other monitors of this type, instrument is only accurate in elastic range of material. Monitor is expected to have broad application in materials testing, structural design, fabrication and assembly.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1993STIN...9426568W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1993STIN...9426568W"><span>Attachment techniques for high temperature <span class="hlt">strain</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wnuk, Steve P., Jr.</p> <p>1993-01-01</p> <p>Attachment methods for making resistive <span class="hlt">strain</span> measurements to 2500 F were studied. A survey of available <span class="hlt">strain</span> gages and attachment techniques was made, and the results are compiled for metal and carbon composite test materials. A theoretical analysis of <span class="hlt">strain</span> transfer into a bonded <span class="hlt">strain</span> gage was made, and the important physical parameters of the <span class="hlt">strain</span> transfer medium, the ceramic matrix, were identified. A pull tester to measure pull-out tests on commonly used <span class="hlt">strain</span> gage cements indicated that all cements tested displayed adequate strength for good <span class="hlt">strain</span> transfer. Rokide flame sprayed coatings produced significantly stronger bonds than ceramic cements. An in-depth study of the flame spray process produced simplified installation procedures which also resulted in greater reliability and durability. Application procedures incorporating improvements made during this program are appended to the report. <span class="hlt">Strain</span> gages installed on carbon composites, Rene' 41, 316 stainless steel, and TZM using attachment techniques developed during this program were successfully tested to 2500 F. Photographs of installation techniques, test procedures, and graphs of the test data are included in this report.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/8719177','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/8719177"><span>A natural vaccine candidate <span class="hlt">strain</span> against cholera.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Liu, Y Q; Qi, G M; Wang, S X; Yu, Y M; Duan, G C; Zhang, L J; Gao, S Y</p> <p>1995-12-01</p> <p>E1 Tor Vibrio cholerae (EVC) <span class="hlt">strains</span> may be classified into two kinds-epidemigenic (EEVC) <span class="hlt">strains</span> and non-epidemigenic (NEEVC) <span class="hlt">strains</span>-based on a phage-biotyping system. A large number of EEVC <span class="hlt">strains</span> have been screened for toxigenic and putative colonization attributes. One such naturally occurring <span class="hlt">strains</span> (designated IEM101) has been found which is devoid of genes encoding cholera toxin (CT), accessory cholera enterotoxin (ACE), zonula occludens toxin (ZOT), but possesses RS1 sequences and toxin-coregulated pilus A gene (icpA) although icpA is poorly expressed. It expresses type B pili but does not possess type C pili. It is an E1 Tor Ogawa <span class="hlt">strain</span> and does not cause fluid accumulation in rabbit ilcal loop tests. Active immunization of rabbits with <span class="hlt">strain</span> IEM101 elicited good protection against challenge with virulent <span class="hlt">strains</span> of V. cholerae O1. Oral administration caused no side effects in 15 human volunteers, colonized the gut for four to ten days and elicited good immune responses.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_20 --> <div id="page_21" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="401"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=nursing+AND+care&id=EJ1001107','ERIC'); return false;" href="http://eric.ed.gov/?q=nursing+AND+care&id=EJ1001107"><span>Medically Complex Home Care and Caregiver <span class="hlt">Strain</span></span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Moorman, Sara M.; Macdonald, Cameron</p> <p>2013-01-01</p> <p>Purpose of the study: To examine (a) whether the content of caregiving tasks (i.e., nursing vs. personal care) contributes to variation in caregivers' <span class="hlt">strain</span> and (b) whether the level of complexity of nursing tasks contributes to variation in <span class="hlt">strain</span> among caregivers providing help with such tasks. Design and methods: The data came from the Cash…</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19700000207','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19700000207"><span>Inorganic bonding of semiconductor <span class="hlt">strain</span> gages</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Woodruff, N. L.</p> <p>1970-01-01</p> <p>Inorganic bonding materials minimize outgassing and improve electrical and mechanical properties of semiconductor <span class="hlt">strain</span>-gage transducers in high-vacuum and high-temperature operations. The two basic methods described are ceramic-glass-bonding and metallic bond formation between the <span class="hlt">strain</span> gage and the substrate.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/82645','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/82645"><span>On certain aspects of <span class="hlt">strain</span> rate sensitivity of sheet metals</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Shi, M.F.; Meuleman, D.J.</p> <p>1995-06-01</p> <p>The formability of a material depends upon the <span class="hlt">strain</span> hardening and <span class="hlt">strain</span> rate hardening of the material. In this study, constitutive parameters using the power law constitutive equation are determined for six different strength steels and two aluminum alloys over different <span class="hlt">strain</span> ranges, including approximations of the postuniform elongation range. Constitutive parameters are found to be different at different <span class="hlt">strain</span> ranges. The <span class="hlt">strain</span> hardening of steels increases with <span class="hlt">strain</span> at low <span class="hlt">strain</span> levels (less than 5%) and decreases at high <span class="hlt">strain</span> levels (greater than 10%). <span class="hlt">Strain</span> rate hardening decreases with <span class="hlt">strain</span> for all steels and aluminum alloys. Uniform elongation depends only on <span class="hlt">strain</span> hardening, and postuniform elongation depends only on <span class="hlt">strain</span> rate hardening. However, the total elongation depends on both <span class="hlt">strain</span> hardening and <span class="hlt">strain</span> rate hardening.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20040090018&hterms=Mechanosensitive+channels&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DMechanosensitive%2Bchannels','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20040090018&hterms=Mechanosensitive+channels&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DMechanosensitive%2Bchannels"><span>Transduction of mechanical <span class="hlt">strain</span> in bone</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Duncan, R. L.</p> <p>1995-01-01</p> <p>One physiologic consequence of extended periods of weightlessness is the rapid loss of bone mass associated with skeletal unloading. Conversely, mechanical loading has been shown to increase bone formation and stimulate osteoblastic function. The mechanisms underlying mechanotransduction, or how the osteoblast senses and converts biophysical stimuli into cellular responses has yet to be determined. For non-innervated mechanosensitive cells like the osteoblast, mechanotransduction can be divided into four distinct phases: 1) mechanocoupling, or the characteristics of the mechanical force applied to the osteoblast, 2) biochemical coupling, or the mechanism through which mechanical <span class="hlt">strain</span> is transduced into a cellular biochemical signal, 3) transmission of signal from sensor to effector cell and 4) the effector cell response. This review examines the characteristics of the mechanical <span class="hlt">strain</span> encountered by osteoblasts, possible biochemical coupling mechanisms, and how the osteoblast responds to mechanical <span class="hlt">strain</span>. Differences in osteoblastic responses to mechanical <span class="hlt">strain</span> are discussed in relation to the types of <span class="hlt">strain</span> encountered and the possible transduction pathways involved.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26649476','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26649476"><span>Mechanical <span class="hlt">strain</span> effects on black phosphorus nanoresonators.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wang, Cui-Xia; Zhang, Chao; Jiang, Jin-Wu; Park, Harold S; Rabczuk, Timon</p> <p>2016-01-14</p> <p>We perform classical molecular dynamics simulations to investigate the effects of mechanical <span class="hlt">strain</span> on single-layer black phosphorus nanoresonators at different temperatures. We find that the resonant frequency is highly anisotropic in black phosphorus due to its intrinsic puckered configuration, and that the quality factor in the armchair direction is higher than in the zigzag direction at room temperature. The quality factors are also found to be intrinsically larger than those in graphene and MoS2 nanoresonators. The quality factors can be increased by more than a factor of two by applying tensile <span class="hlt">strain</span>, with uniaxial <span class="hlt">strain</span> in the armchair direction being the most effective. However, there is an upper bound for the quality factor increase due to nonlinear effects at large <span class="hlt">strains</span>, after which the quality factor decreases. The tension induced nonlinear effect is stronger along the zigzag direction, resulting in a smaller maximum <span class="hlt">strain</span> for quality factor enhancement.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/24799688','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/24799688"><span>Extraordinary <span class="hlt">strain</span> hardening by gradient structure.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Wu, XiaoLei; Jiang, Ping; Chen, Liu; Yuan, Fuping; Zhu, Yuntian T</p> <p>2014-05-20</p> <p>Gradient structures have evolved over millions of years through natural selection and optimization in many biological systems such as bones and plant stems, where the structures change gradually from the surface to interior. The advantage of gradient structures is their maximization of physical and mechanical performance while minimizing material cost. Here we report that the gradient structure in engineering materials such as metals renders a unique extra <span class="hlt">strain</span> hardening, which leads to high ductility. The grain-size gradient under uniaxial tension induces a macroscopic <span class="hlt">strain</span> gradient and converts the applied uniaxial stress to multiaxial stresses due to the evolution of incompatible deformation along the gradient depth. Thereby the accumulation and interaction of dislocations are promoted, resulting in an extra <span class="hlt">strain</span> hardening and an obvious <span class="hlt">strain</span> hardening rate up-turn. Such extraordinary <span class="hlt">strain</span> hardening, which is inherent to gradient structures and does not exist in homogeneous materials, provides a hitherto unknown strategy to develop strong and ductile materials by architecting heterogeneous nanostructures.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/6565562','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/6565562"><span><span class="hlt">Strain</span> rate effects in stress corrosion cracking</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Parkins, R.N. . Dept. of Metallurgy and Engineering Materials)</p> <p>1990-03-01</p> <p>Slow <span class="hlt">strain</span> rate testing (SSRT) was initially developed as a rapid, ad hoc laboratory method for assessing the propensity for metals an environments to promote stress corrosion cracking. It is now clear, however, that there are good theoretical reasons why <span class="hlt">strain</span> rate, as opposed to stress per se, will often be the controlling parameter in determining whether or not cracks are nucleated and, if so, are propagated. The synergistic effects of the time dependence of corrosion-related reactions and microplastic <span class="hlt">strain</span> provide the basis for mechanistic understanding of stress corrosion cracking in high-pressure pipelines and other structures. However, while this may be readily comprehended in the context of laboratory slow <span class="hlt">strain</span> tests, its extension to service situations may be less apparent. Laboratory work involving realistic stressing conditions, including low-frequency cyclic loading, shows that <span class="hlt">strain</span> or creep rates give good correlation with thresholds for cracking and with crack growth kinetics.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..1810513Q','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..1810513Q"><span>Micro-scale <span class="hlt">strain</span> mapping technique: a tool to quantify <span class="hlt">strain</span> partitioning during creep deformation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Quintanilla-Terminel, Alejandra; Zimmerman, Mark; Evans, Brian; Kohlstedt, David</p> <p>2016-04-01</p> <p>Several deformation mechanisms interact to accommodate plastic deformation. Quantifying the contribution of each to the total <span class="hlt">strain</span> is necessary for establishing a better link between observed microstructures and mechanical data, as well as to allow more confident extrapolation from laboratory to natural conditions. In this contribution, we present the experimental and computational technique involved in micro-scale <span class="hlt">strain</span> mapping (MSSM). The MSSM technique relies on analyzing the relative displacement of initially regularly spaced markers after deformation. We present several microfabrication techniques that permit us to pattern various rocks with micrometric and nanometric metal markers, as well as the challenges faced in working at high temperatures and pressures. A Hough transform algorithm was used to detect the markers and automate as much as possible the <span class="hlt">strain</span> analysis. The von Mises <span class="hlt">strain</span> is calculated for a set of n-points and their relative displacements, which allow us to map the <span class="hlt">strain</span> at different length scales. We applied the MSSM technique to study <span class="hlt">strain</span> partitioning during deformation creep of Carrara marble and San Carlos olivine at a confining pressure, Pc, of 300 MPa and homologous temperatures of 0.3 to 0.6. We measured the local <span class="hlt">strain</span> and <span class="hlt">strain</span> heterogeneity produced during creep deformation of split cylinders of Carrara marble under conventional triaxial loading to inelastic <span class="hlt">strains</span> of 11 to 36% at a <span class="hlt">strain</span> rate of 3x10-5s-1, Pc = 300 MPa and 400o < T <700oC. We conclude that the evolution of deformation structures in marble takes place over a substantial interval in <span class="hlt">strain</span> and that the duration of this interval depends on <span class="hlt">strain</span> rate, temperature, and pressure. Our first results on <span class="hlt">strain</span> mapping of olivine deformed at T = 1150oC and Pc = 300 MPa demonstrate promise for characterizing intragranular <span class="hlt">strain</span> and better defining the contribution of grain boundary sliding to the total <span class="hlt">strain</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2551748','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2551748"><span>Amerindian Helicobacter pylori <span class="hlt">Strains</span> Go Extinct, as European <span class="hlt">Strains</span> Expand Their Host Range</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Domínguez-Bello, Maria G.; Pérez, Maria E.; Bortolini, Maria C.; Salzano, Francisco M.; Pericchi, Luis R.; Zambrano-Guzmán, Orlisbeth; Linz, Bodo</p> <p>2008-01-01</p> <p>We studied the diversity of bacteria and host in the H. pylori-human model. The human indigenous bacterium H. pylori diverged along with humans, into African, European, Asian and Amerindian groups. Of these, Amerindians have the least genetic diversity. Since niche diversity widens the sets of resources for colonizing species, we predicted that the Amerindian H. pylori <span class="hlt">strains</span> would be the least diverse. We analyzed the multilocus sequence (7 housekeeping genes) of 131 <span class="hlt">strains</span>: 19 cultured from Africans, 36 from Spanish, 11 from Koreans, 43 from Amerindians and 22 from South American Mestizos. We found that all <span class="hlt">strains</span> that had been cultured from Africans were African <span class="hlt">strains</span> (hpAfrica1), all from Spanish were European (hpEurope) and all from Koreans were hspEAsia but that Amerindians and Mestizos carried mixed <span class="hlt">strains</span>: hspAmerind and hpEurope <span class="hlt">strains</span> had been cultured from Amerindians and hpEurope and hpAfrica1 were cultured from Mestizos. The least genetically diverse H. pylori <span class="hlt">strains</span> were hspAmerind. <span class="hlt">Strains</span> hpEurope were the most diverse and showed remarkable multilocus sequence mosaicism (indicating recombination). The lower genetic structure in hpEurope <span class="hlt">strains</span> is consistent with colonization of a diversity of hosts. If diversity is important for the success of H. pylori, then the low diversity of Amerindian <span class="hlt">strains</span> might be linked to their apparent tendency to disappear. This suggests that Amerindian <span class="hlt">strains</span> may lack the needed diversity to survive the diversity brought by non-Amerindian hosts. PMID:18830403</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28049090','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28049090"><span>New regime in the mechanical behavior of skin: <span class="hlt">strain</span>-softening occurring before <span class="hlt">strain</span>-hardening.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Nicolle, S; Decorps, J; Fromy, B; Palierne, J-F</p> <p>2017-05-01</p> <p>We report linear and non-linear shear tests on rat skin, evidencing a <span class="hlt">strain</span>-softening regime, from 1% to 50% <span class="hlt">strain</span>, followed by a strong <span class="hlt">strain</span>-hardening regime, leading to a 'deck chair-shaped' stress-<span class="hlt">strain</span> curve. The <span class="hlt">strain</span>-softening regime was never reported as such in the literature, possibly mistaken for the linear regime in experiments starting above 1% deformation. The time-dependent response is akin to that of a gel, with a power-law frequency-dependent dynamic shear modulus ranging from ~5.6kPa to ~10kPa between 0.1Hz and 10Hz. We present an analytical non-linear viscoelastic model that accounts for both time-dependent and <span class="hlt">strain</span>-dependent features of the skin. This eight-parameter model extends the one we proposed for parenchymatous organs by including <span class="hlt">strain</span>-softening.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/23030102','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/23030102"><span>Anisotropic <span class="hlt">strain</span> enhanced hydrogen solubility in bcc metals: the independence on the sign of <span class="hlt">strain</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zhou, Hong-Bo; Jin, Shuo; Zhang, Ying; Lu, Guang-Hong; Liu, Feng</p> <p>2012-09-28</p> <p>When an impurity is doped in a solid, it inevitably induces a local stress, tending to expand or contract the lattice. Consequently, <span class="hlt">strain</span> can be applied to change the solubility of impurity in a solid. Generally, the solubility responds to <span class="hlt">strain</span> "monotonically," increasing (decreasing) with the tensile (compressive) <span class="hlt">strain</span> if the impurity induces a compressive stress or vice versa. Using first-principles calculations, however, we discovered that the H solubility can be enhanced by anisotropic <span class="hlt">strain</span> in some bcc metals, almost independent of the sign of <span class="hlt">strain</span>. This anomalous behavior is found to be caused by a continuous change of H location induced by anisotropic <span class="hlt">strain</span>. Our finding suggests a cascading effect of H bubble formation in bcc metals: the H solution leads to H bubble formation that induces anisotropic <span class="hlt">strain</span> that in turn enhances H solubility to further facilitate bubble growth.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008IJMPB..22.1255K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008IJMPB..22.1255K"><span>Dynamic Tensile Properties of Iron and Steels for a Wide Range of <span class="hlt">Strain</span> Rates and <span class="hlt">Strain</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kojima, Nobusato; Hayashi, Hiroyuki; Yamamoto, Terumi; Mimura, Koji; Tanimura, Shinji</p> <p></p> <p>The tensile stress-<span class="hlt">strain</span> curves of iron and a variety of steels, covering a wide range of strength level, over a wide <span class="hlt">strain</span> rate range on the order of 10-3 ~ 103 s-1, were obtained systematically by using the Sensing Block Type High Speed Material Testing System (SBTS, Saginomiya). Through intensive analysis of these results, the <span class="hlt">strain</span> rate sensitivity of the flow stress for the large <span class="hlt">strain</span> region, including the viscous term at high <span class="hlt">strain</span> rates, the true fracture strength and the true fracture <span class="hlt">strain</span> were cleared for the material group of the ferrous metals. These systematical data may be useful to develop a practical constitutive model for computer codes, including a fracture criterion for simulations of the dynamic behavior in crash worthiness studies and of work-pieces subjected to dynamic plastic working for a wide <span class="hlt">strain</span> rate range.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007IJMSp.259..140K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007IJMSp.259..140K"><span>Specific identification of Bacillus anthracis <span class="hlt">strains</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Krishnamurthy, Thaiya; Deshpande, Samir; Hewel, Johannes; Liu, Hongbin; Wick, Charles H.; Yates, John R., III</p> <p>2007-01-01</p> <p>Accurate identification of human pathogens is the initial vital step in treating the civilian terrorism victims and military personnel afflicted in biological threat situations. We have applied a powerful multi-dimensional protein identification technology (MudPIT) along with newly generated software termed Profiler to identify the sequences of specific proteins observed for few <span class="hlt">strains</span> of Bacillus anthracis, a human pathogen. Software termed Profiler was created to initially screen the MudPIT data of B. anthracis <span class="hlt">strains</span> and establish the observed proteins specific for its <span class="hlt">strains</span>. A database was also generated using Profiler containing marker proteins of B. anthracis and its <span class="hlt">strains</span>, which in turn could be used for detecting the organism and its corresponding <span class="hlt">strains</span> in samples. Analysis of the unknowns by our methodology, combining MudPIT and Profiler, led to the accurate identification of the anthracis <span class="hlt">strains</span> present in samples. Thus, a new approach for the identification of B. anthracis <span class="hlt">strains</span> in unknown samples, based on the molecular mass and sequences of marker proteins, has been ascertained.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006PMB....51.5245T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006PMB....51.5245T"><span>Resolution of axial shear <span class="hlt">strain</span> elastography</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Thitaikumar, Arun; Righetti, Raffaella; Krouskop, Thomas A.; Ophir, Jonathan</p> <p>2006-10-01</p> <p>The technique of mapping the local axial component of the shear <span class="hlt">strain</span> due to quasi-static axial compression is defined as axial shear <span class="hlt">strain</span> elastography. In this paper, the spatial resolution of axial shear <span class="hlt">strain</span> elastography is investigated through simulations, using an elastically stiff cylindrical lesion embedded in a homogeneously softer background. Resolution was defined as the smallest size of the inclusion for which the <span class="hlt">strain</span> value at the inclusion/background interface was greater than the average of the axial shear <span class="hlt">strain</span> values at the interface and inside the inclusion. The resolution was measured from the axial shear <span class="hlt">strain</span> profile oriented at 45° to the axis of beam propagation, due to the absence of axial shear <span class="hlt">strain</span> along the normal directions. The effects of the ultrasound system parameters such as bandwidth, beamwidth and transducer element pitch along with signal processing parameters such as correlation window length (W) and axial shift (ΔW) on the estimated resolution were investigated. The results show that the resolution (at 45° orientation) is determined by the bandwidth and the beamwidth. However, the upper bound on the resolution is limited by the larger of the beamwidth and the window length, which is scaled inversely to the bandwidth. The results also show that the resolution is proportional to the pitch and not significantly affected by the axial window shift.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26529510','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26529510"><span>Highly Invasive Listeria monocytogenes <span class="hlt">Strains</span> Have Growth and Invasion Advantages in <span class="hlt">Strain</span> Competition.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zilelidou, Evangelia A; Rychli, Kathrin; Manthou, Evanthia; Ciolacu, Luminita; Wagner, Martin; Skandamis, Panagiotis N</p> <p>2015-01-01</p> <p>Multiple Listeria monocytogenes <span class="hlt">strains</span> can be present in the same food sample; moreover, infection with more than one L. monocytogenes <span class="hlt">strain</span> can also occur. In this study we investigated the impact of <span class="hlt">strain</span> competition on the growth and in vitro virulence potential of L. monocytogenes. We identified two strong competitor <span class="hlt">strains</span>, whose growth was not (or only slightly) influenced by the presence of other <span class="hlt">strains</span> and two weak competitor <span class="hlt">strains</span>, which were outcompeted by other <span class="hlt">strains</span>. Cell contact was essential for growth inhibition. In vitro virulence assays using human intestinal epithelial Caco2 cells showed a correlation between the invasion efficiency and growth inhibition: the strong growth competitor <span class="hlt">strains</span> showed high invasiveness. Moreover, invasion efficiency of the highly invasive <span class="hlt">strain</span> was further increased in certain combinations by the presence of a low invasive <span class="hlt">strain</span>. In all tested combinations, the less invasive <span class="hlt">strain</span> was outcompeted by the higher invasive <span class="hlt">strain</span>. Studying the effect of cell contact on in vitro virulence competition revealed a complex pattern in which the observed effects depended only partially on cell-contact suggesting that competition occurs at two different levels: i) during co-cultivation prior to infection, which might influence the expression of virulence factors, and ii) during infection, when bacterial cells compete for the host cell. In conclusion, we show that growth of L. monocytogenes can be inhibited by <span class="hlt">strains</span> of the same species leading potentially to biased recovery during enrichment procedures. Furthermore, the presence of more than one L. monocytogenes <span class="hlt">strain</span> in food can lead to increased infection rates due to synergistic effects on the virulence potential.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4631365','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4631365"><span>Highly Invasive Listeria monocytogenes <span class="hlt">Strains</span> Have Growth and Invasion Advantages in <span class="hlt">Strain</span> Competition</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Manthou, Evanthia; Ciolacu, Luminita; Wagner, Martin; Skandamis, Panagiotis N.</p> <p>2015-01-01</p> <p>Multiple Listeria monocytogenes <span class="hlt">strains</span> can be present in the same food sample; moreover, infection with more than one L. monocytogenes <span class="hlt">strain</span> can also occur. In this study we investigated the impact of <span class="hlt">strain</span> competition on the growth and in vitro virulence potential of L. monocytogenes. We identified two strong competitor <span class="hlt">strains</span>, whose growth was not (or only slightly) influenced by the presence of other <span class="hlt">strains</span> and two weak competitor <span class="hlt">strains</span>, which were outcompeted by other <span class="hlt">strains</span>. Cell contact was essential for growth inhibition. In vitro virulence assays using human intestinal epithelial Caco2 cells showed a correlation between the invasion efficiency and growth inhibition: the strong growth competitor <span class="hlt">strains</span> showed high invasiveness. Moreover, invasion efficiency of the highly invasive <span class="hlt">strain</span> was further increased in certain combinations by the presence of a low invasive <span class="hlt">strain</span>. In all tested combinations, the less invasive <span class="hlt">strain</span> was outcompeted by the higher invasive <span class="hlt">strain</span>. Studying the effect of cell contact on in vitro virulence competition revealed a complex pattern in which the observed effects depended only partially on cell-contact suggesting that competition occurs at two different levels: i) during co-cultivation prior to infection, which might influence the expression of virulence factors, and ii) during infection, when bacterial cells compete for the host cell. In conclusion, we show that growth of L. monocytogenes can be inhibited by <span class="hlt">strains</span> of the same species leading potentially to biased recovery during enrichment procedures. Furthermore, the presence of more than one L. monocytogenes <span class="hlt">strain</span> in food can lead to increased infection rates due to synergistic effects on the virulence potential. PMID:26529510</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JGRB..121.5736Q','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JGRB..121.5736Q"><span>Heterogeneity of inelastic <span class="hlt">strain</span> during creep of Carrara marble: Microscale <span class="hlt">strain</span> measurement technique</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Quintanilla-Terminel, Alejandra; Evans, Brian</p> <p>2016-08-01</p> <p>We combined the split cylinder technique with microfabrication technology to observe <span class="hlt">strain</span> heterogeneities that were produced during high-pressure transient creep of Carrara marble. Samples were patterned with a custom-designed grid of markers spaced 10 µm apart and containing an embedded coordinate system. The microscale <span class="hlt">strain</span> measurement (MSSM) technique described here allowed us to analyze the local <span class="hlt">strain</span> distribution with unprecedented detail over large regions. The description of the <span class="hlt">strain</span> field is a function of the area over which <span class="hlt">strain</span> is being computed. The scale at which the <span class="hlt">strain</span> field can be considered homogeneous can provide insight into the deformation processes taking place. At 400-500°C, when twinning production is prolific, we observe highly <span class="hlt">strained</span> bands that span several grains. One possible cause for the multigrain bands is the need to relieve <span class="hlt">strain</span> incompatibilities that result when twins impinge on neighboring grains. At 600-700°C, the <span class="hlt">strain</span> fields are still quite heterogeneous, and local <span class="hlt">strain</span> varies substantially within grains and near grain boundaries, but the multigrain slip bands are not present. Deformation is concentrated in much smaller areas within grains and along some grain boundaries. The disappearance of the multigrain slip bands occurs when the deformation conditions allow additional slip systems to be activated. At 600°C, when the total <span class="hlt">strain</span> is varied from 0.11 to 0.36, the spatial scale of the heterogeneity does not vary, but there are increases in the standard deviation of the distribution of local <span class="hlt">strains</span> normalized by the total <span class="hlt">strain</span>; thus, we conclude that the microstructure does not achieve a steady state in this <span class="hlt">strain</span> interval.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/10888638','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/10888638"><span>Genetic diversity among Lassa virus <span class="hlt">strains</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Bowen, M D; Rollin, P E; Ksiazek, T G; Hustad, H L; Bausch, D G; Demby, A H; Bajani, M D; Peters, C J; Nichol, S T</p> <p>2000-08-01</p> <p>The arenavirus Lassa virus causes Lassa fever, a viral hemorrhagic fever that is endemic in the countries of Nigeria, Sierra Leone, Liberia, and Guinea and perhaps elsewhere in West Africa. To determine the degree of genetic diversity among Lassa virus <span class="hlt">strains</span>, partial nucleoprotein (NP) gene sequences were obtained from 54 <span class="hlt">strains</span> and analyzed. Phylogenetic analyses showed that Lassa viruses comprise four lineages, three of which are found in Nigeria and the fourth in Guinea, Liberia, and Sierra Leone. Overall <span class="hlt">strain</span> variation in the partial NP gene sequence was found to be as high as 27% at the nucleotide level and 15% at the amino acid level. Genetic distance among Lassa <span class="hlt">strains</span> was found to correlate with geographic distance rather than time, and no evidence of a "molecular clock" was found. A method for amplifying and cloning full-length arenavirus S RNAs was developed and used to obtain the complete NP and glycoprotein gene (GP1 and GP2) sequences for two representative Nigerian <span class="hlt">strains</span> of Lassa virus. Comparison of full-length gene sequences for four Lassa virus <span class="hlt">strains</span> representing the four lineages showed that the NP gene (up to 23.8% nucleotide difference and 12.0% amino acid difference) is more variable than the glycoprotein genes. Although the evolutionary order of descent within Lassa virus <span class="hlt">strains</span> was not completely resolved, the phylogenetic analyses of full-length NP, GP1, and GP2 gene sequences suggested that Nigerian <span class="hlt">strains</span> of Lassa virus were ancestral to <span class="hlt">strains</span> from Guinea, Liberia, and Sierra Leone. Compared to the New World arenaviruses, Lassa and the other Old World arenaviruses have either undergone a shorter period of diverisification or are evolving at a slower rate. This study represents the first large-scale examination of Lassa virus genetic variation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003AGUFM.V12A0552Q','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003AGUFM.V12A0552Q"><span>Microstructural Analysis of Welding: Deformation and <span class="hlt">Strain</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Quane, S. L.; Russell, K.</p> <p>2003-12-01</p> <p>Welding in pyroclastic deposits involves the sintering, compaction and flattening of hot glassy particles and is attended by systematic changes in physical properties. Welded materials contain implicit information regarding the total accumulated <span class="hlt">strain</span> as well as the mechanisms of deformation. Here, we use detailed microstructural analysis of synthetic and natural welded materials to make quantitative estimates of <span class="hlt">strain</span> and constrain the rheology of these materials during the welding process. Part one of our study comprises microstructural analysis of end products from unconfined high temperature deformation experiments on sintered cores of soda-lime silica glass spheres. This analogue material has relatively simple and well-characterized starting properties. Furthermore, the initially spherical shapes of particles provide excellent <span class="hlt">strain</span> markers. Experiments were run at a variety of temperatures, <span class="hlt">strain</span> rates and stresses resulting in end products with varying degrees of total <span class="hlt">strain</span>. The nature of <span class="hlt">strain</span> partitioning and accumulation are evaluated using image analysis techniques on scanned images and photomicrographs of thin sections cut perpendicular to the loading direction of each experimental product. Shapes of the individual deformed particles (e.g., oblate spheroids) were determined and the Scion image analysis program was used to create a best-fit ellipse for each particle. Statistics collected on each particle include: axial dimension (a), vertical dimension (c) and angle from the horizontal. The data are used to calculate the oblateness of each particle (1-c/a) and the angle of deformation induced foliation. Furthermore, the relative proportions of visible blue epoxy in the sample scans determine bulk porosity. The average oblateness of the particles is a direct, independent measure of the accumulated <span class="hlt">strain</span> in each sample. Results indicate that these measured values are equal to calculated theoretical values of oblateness for spheroids undergoing the</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/6239469','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/6239469"><span>Differentiation of pathogenic and saprophytic leptospira <span class="hlt">strains</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Bazovská, S; Kmety, E; Rak, J</p> <p>1984-09-01</p> <p>Comparative studies of 249 pathogenic and 80 saprophytic leptospira <span class="hlt">strains</span>, including 2 <span class="hlt">strains</span> of the illini type, using the 8-azaguanine test, growth at 13 degrees C and growth on trypticase soy broth revealed their good differentiating potency if the recommended conditions were carefully observed. The same results were obtained by a simple hemolytic test using sheep and rat blood cells, having the advantage of providing results within 24 h. This test is suggested to replace the 8-azaguanine and the growth test at 13 degrees C. In these investigations, the first European <span class="hlt">strain</span> of the illini type was recognized.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_21 --> <div id="page_22" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="421"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/21506808','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/21506808"><span><span class="hlt">Strain</span> Determination Using Electron Backscatter Diffraction</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Krause, M.; Graff, A.; Altmann, F.</p> <p>2010-11-24</p> <p>In the present paper we demonstrate the use of electron backscatter diffraction (EBSD) for high resolution elastic <span class="hlt">strain</span> determination. Here, we focus on analysis methods based on determination of small shifts in EBSD pattern with respect to a reference pattern using cross-correlation algorithms. Additionally we highlight the excellent spatial and depth resolution of EBSD and introduce the use of simulated diffraction patterns based on dynamical diffraction theory for sensitivity estimation. Moreover the potential of EBSD for <span class="hlt">strain</span> analysis of <span class="hlt">strained</span> thin films with particular emphasis on appropriate target preparation which respect to occurring lattice defects is demonstrated.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/10543843','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/10543843"><span>Genotypic diversity among Brevibacillus laterosporus <span class="hlt">strains</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zahner, V; Rabinovitch, L; Suffys, P; Momen, H</p> <p>1999-11-01</p> <p>In comparison with other entomopathogenic Bacillus species, the genome of Brevibacillus laterosporus is poorly characterized. The aim of this study was to examine genetic variability in B. laterosporus by using a range of typing methodologies. <span class="hlt">Strains</span> of B. laterosporus were examined for variation in 13 chromosomal genes encoding enzymes by multilocus enzyme electrophoresis. Optimal conditions of pulsed-field gel electrophoresis and randomly amplified polymorphic DNA were established that allowed analysis of the genome of B. laterosporus. None of these techniques allowed the identification of a convenient molecular marker for entomopathogenic <span class="hlt">strains</span>, although one specific primer amplified only DNA from almost all mosquitocidal <span class="hlt">strains</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2014-title40-vol24/pdf/CFR-2014-title40-vol24-sec180-1209.pdf','CFR2014'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2014-title40-vol24/pdf/CFR-2014-title40-vol24-sec180-1209.pdf"><span>40 CFR 180.1209 - Bacillus subtilis <span class="hlt">strain</span> QST 713 and <span class="hlt">strain</span> QST 713 variant soil; exemption from the requirement...</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2014&page.go=Go">Code of Federal Regulations, 2014 CFR</a></p> <p></p> <p>2014-07-01</p> <p>... <span class="hlt">strain</span> QST 713 variant soil; exemption from the requirement of a tolerance. 180.1209 Section 180.1209... <span class="hlt">strain</span> QST 713 and <span class="hlt">strain</span> QST 713 variant soil; exemption from the requirement of a tolerance. An... Bacillus subtilis <span class="hlt">strain</span> QST 713 and <span class="hlt">strain</span> QST 713 variant soil when used in or on all food commodities....</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/CFR-2013-title40-vol25/pdf/CFR-2013-title40-vol25-sec180-1209.pdf','CFR2013'); return false;" href="https://www.gpo.gov/fdsys/pkg/CFR-2013-title40-vol25/pdf/CFR-2013-title40-vol25-sec180-1209.pdf"><span>40 CFR 180.1209 - Bacillus subtilis <span class="hlt">strain</span> QST 713 and <span class="hlt">strain</span> QST 713 variant soil; exemption from the requirement...</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collectionCfr.action?selectedYearFrom=2013&page.go=Go">Code of Federal Regulations, 2013 CFR</a></p> <p></p> <p>2013-07-01</p> <p>... <span class="hlt">strain</span> QST 713 variant soil; exemption from the requirement of a tolerance. 180.1209 Section 180.1209... <span class="hlt">strain</span> QST 713 and <span class="hlt">strain</span> QST 713 variant soil; exemption from the requirement of a tolerance. An... Bacillus subtilis <span class="hlt">strain</span> QST 713 and <span class="hlt">strain</span> QST 713 variant soil when used in or on all food commodities....</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014SPIE.9040E..15Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014SPIE.9040E..15Y"><span>A new radial <span class="hlt">strain</span> and <span class="hlt">strain</span> rate estimation method using autocorrelation for carotid artery</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ye, Jihui; Kim, Hoonmin; Park, Jongho; Yeo, Sunmi; Shim, Hwan; Lim, Hyungjoon; Yoo, Yangmo</p> <p>2014-03-01</p> <p>Atherosclerosis is a leading cause of cardiovascular disease. The early diagnosis of atherosclerosis is of clinical interest since it can prevent any adverse effects of atherosclerotic vascular diseases. In this paper, a new carotid artery radial <span class="hlt">strain</span> estimation method based on autocorrelation is presented. In the proposed method, the <span class="hlt">strain</span> is first estimated by the autocorrelation of two complex signals from the consecutive frames. Then, the angular phase from autocorrelation is converted to <span class="hlt">strain</span> and <span class="hlt">strain</span> rate and they are analyzed over time. In addition, a 2D <span class="hlt">strain</span> image over region of interest in a carotid artery can be displayed. To evaluate the feasibility of the proposed radial <span class="hlt">strain</span> estimation method, radiofrequency (RF) data of 408 frames in the carotid artery of a volunteer were acquired by a commercial ultrasound system equipped with a research package (V10, Samsung Medison, Korea) by using a L5-13IS linear array transducer. From in vivo carotid artery data, the mean <span class="hlt">strain</span> estimate was -0.1372 while its minimum and maximum values were -2.961 and 0.909, respectively. Moreover, the overall <span class="hlt">strain</span> estimates are highly correlated with the reconstructed M-mode trace. Similar results were obtained from the estimation of the <span class="hlt">strain</span> rate change over time. These results indicate that the proposed carotid artery radial <span class="hlt">strain</span> estimation method is useful for assessing the arterial wall's stiffness noninvasively without increasing the computational complexity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25769835','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25769835"><span>Tropical <span class="hlt">strains</span> of Ralstonia solanacearum Outcompete race 3 biovar 2 <span class="hlt">strains</span> at lowland tropical temperatures.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Huerta, Alejandra I; Milling, Annett; Allen, Caitilyn</p> <p>2015-05-15</p> <p>Bacterial wilt, caused by members of the heterogenous Ralstonia solanacearum species complex, is an economically important vascular disease affecting many crops. Human activity has widely disseminated R. solanacearum <span class="hlt">strains</span>, increasing their global agricultural impact. However, tropical highland race 3 biovar 2 (R3bv2) <span class="hlt">strains</span> do not cause disease in tropical lowlands, even though they are virulent at warm temperatures. We tested the hypothesis that differences in temperature adaptation and competitive fitness explain the uneven geographic distribution of R. solanacearum <span class="hlt">strains</span>. Using three phylogenetically and ecologically distinct <span class="hlt">strains</span>, we measured competitive fitness at two temperatures following paired-<span class="hlt">strain</span> inoculations of their shared host, tomato. Lowland tropical <span class="hlt">strain</span> GMI1000 was only weakly virulent on tomato under temperate conditions (24°C for day and 19°C for night [24/19°C]), but highland tropical R3bv2 <span class="hlt">strain</span> UW551 and U.S. warm temperate <span class="hlt">strain</span> K60 were highly virulent at both 24/19°C and 28°C. <span class="hlt">Strain</span> K60 was significantly more competitive than both GMI1000 and UW551 in tomato rhizospheres and stems at 28°C, and GMI1000 also outcompeted UW551 at 28°C. The results were reversed at cooler temperatures, at which highland <span class="hlt">strain</span> UW551 generally outcompeted GMI1000 and K60 in planta. The superior competitive index of UW551 at 24/19°C suggests that adaptation to cool temperatures could explain why only R3bv2 <span class="hlt">strains</span> threaten highland agriculture. <span class="hlt">Strains</span> K60 and GMI1000 each produced different bacteriocins that inhibited growth of UW551 in culture. Such interstrain inhibition could explain why R3bv2 <span class="hlt">strains</span> do not cause disease in tropical lowlands.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4407210','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4407210"><span>Tropical <span class="hlt">Strains</span> of Ralstonia solanacearum Outcompete Race 3 Biovar 2 <span class="hlt">Strains</span> at Lowland Tropical Temperatures</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Huerta, Alejandra I.; Milling, Annett</p> <p>2015-01-01</p> <p>Bacterial wilt, caused by members of the heterogenous Ralstonia solanacearum species complex, is an economically important vascular disease affecting many crops. Human activity has widely disseminated R. solanacearum <span class="hlt">strains</span>, increasing their global agricultural impact. However, tropical highland race 3 biovar 2 (R3bv2) <span class="hlt">strains</span> do not cause disease in tropical lowlands, even though they are virulent at warm temperatures. We tested the hypothesis that differences in temperature adaptation and competitive fitness explain the uneven geographic distribution of R. solanacearum <span class="hlt">strains</span>. Using three phylogenetically and ecologically distinct <span class="hlt">strains</span>, we measured competitive fitness at two temperatures following paired-<span class="hlt">strain</span> inoculations of their shared host, tomato. Lowland tropical <span class="hlt">strain</span> GMI1000 was only weakly virulent on tomato under temperate conditions (24°C for day and 19°C for night [24/19°C]), but highland tropical R3bv2 <span class="hlt">strain</span> UW551 and U.S. warm temperate <span class="hlt">strain</span> K60 were highly virulent at both 24/19°C and 28°C. <span class="hlt">Strain</span> K60 was significantly more competitive than both GMI1000 and UW551 in tomato rhizospheres and stems at 28°C, and GMI1000 also outcompeted UW551 at 28°C. The results were reversed at cooler temperatures, at which highland <span class="hlt">strain</span> UW551 generally outcompeted GMI1000 and K60 in planta. The superior competitive index of UW551 at 24/19°C suggests that adaptation to cool temperatures could explain why only R3bv2 <span class="hlt">strains</span> threaten highland agriculture. <span class="hlt">Strains</span> K60 and GMI1000 each produced different bacteriocins that inhibited growth of UW551 in culture. Such interstrain inhibition could explain why R3bv2 <span class="hlt">strains</span> do not cause disease in tropical lowlands. PMID:25769835</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004SPIE.5373..173T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004SPIE.5373..173T"><span>Simultaneous narrowband ultrasonic <span class="hlt">strain</span>-flow imaging</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tsou, Jean K.; Mai, Jerome J.; Lupotti, Fermin A.; Insana, Michael F.</p> <p>2004-04-01</p> <p>We are summarizing new research aimed at forming spatially and temporally registered combinations of <span class="hlt">strain</span> and color-flow images using echo data recorded from a commercial ultrasound system. Applications include diagnosis of vascular diseases and tumor malignancies. The challenge is to meet the diverse needs of each measurement. The approach is to first apply eigenfilters that separate echo components from moving tissues and blood flow, and then estimate blood velocity and tissue displacement from the filtered-IQ-signal phase modulations. At the cost of a lower acquisition frame rate, we find the autocorrelation <span class="hlt">strain</span> estimator yields higher resolution <span class="hlt">strain</span> estimate than the cross-correlator since estimates are made from ensembles at a single point in space. The technique is applied to in vivo carotid imaging, to demonstrate the sensitivity for <span class="hlt">strain</span>-flow vascular imaging.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://kidshealth.org/en/parents/broken-bones.html','NIH-MEDLINEPLUS'); return false;" href="https://kidshealth.org/en/parents/broken-bones.html"><span>Broken Bones, Sprains, and <span class="hlt">Strains</span> (For Parents)</span></a></p> <p><a target="_blank" href="http://medlineplus.gov/">MedlinePlus</a></p> <p></p> <p></p> <p>... Feeding Your 1- to 2-Year-Old Broken Bones, Sprains, and <span class="hlt">Strains</span> KidsHealth > For Parents > Broken Bones, ... home. What to Do: For a Suspected Broken Bone: Do not move a child whose injury involves ...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ApPhL.107s3102G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ApPhL.107s3102G"><span>Tuning <span class="hlt">strain</span> in flexible graphene nanoelectromechanical resonators</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Guan, Fen; Kumaravadivel, Piranavan; Averin, Dmitri V.; Du, Xu</p> <p>2015-11-01</p> <p>The structural flexibility of low dimensional nanomaterials offers unique opportunities for studying the impact of <span class="hlt">strain</span> on their physical properties and for developing innovative devices utilizing <span class="hlt">strain</span> engineering. A key towards such goals is a device platform which allows the independent tuning and reliable calibration of the <span class="hlt">strain</span>. Here, we report the fabrication and characterization of graphene nanoelectromechanical resonators (GNEMRs) on flexible substrates. Combining substrate bending and electrostatic gating, we achieve the independent tuning of the <span class="hlt">strain</span> and sagging in graphene and explore the nonlinear dynamics over a wide parameter space. Analytical and numerical studies of a continuum mechanics model, including the competing higher order nonlinear terms, reveal a comprehensive nonlinear dynamics phase diagram, which quantitatively explains the complex behaviors of GNEMRs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=243113','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=243113"><span>Carotene-superproducing <span class="hlt">strains</span> of Phycomyces.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Murillo, F J; Calderón, I L; López-Díaz, I; Cerdá-Olmedo, E</p> <p>1978-01-01</p> <p>Production of beta-carotene by wild-type Phycomyces blakesleeanus can be stimulated by light, chemicals, regulatory mutations, and sexual interaction between mycelia of opposite sex. Through genetic manipulations, we have isolated <span class="hlt">strains</span> which have simultaneously and constitutively incorporated several of these stimulatory effects. In the dark and in a simple medium, some of the <span class="hlt">strains</span> produce up to 25 mg of beta-carotene per g (dry weight), or about 500 times the wild-type production under the same conditions. High lycopene-producing <span class="hlt">strains</span> have also been isolated by using carR mutants, which are blocked in the conversion of lycopene to beta-carotene. These <span class="hlt">strains</span> should be useful in both industrial production of these pigments and basic research related to carotenogenesis. PMID:727783</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19940008401','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19940008401"><span><span class="hlt">Strain</span> sensing technology for high temperature applications</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Williams, W. Dan</p> <p>1993-01-01</p> <p>This review discusses the status of <span class="hlt">strain</span> sensing technology for high temperature applications. Technologies covered are those supported by NASA such as required for applications in hypersonic vehicles and engines, advanced subsonic engines, as well as material and structure development. The applications may be at temperatures of 540 C (1000 F) to temperatures in excess of 1400 C (2500 F). The most promising technologies at present are the resistance <span class="hlt">strain</span> gage and remote sensing schemes. Resistance <span class="hlt">strain</span> gages discussed include the BCL gage, the LaRC compensated gage, and the PdCr gage. Remote sensing schemes such as laser based speckle <span class="hlt">strain</span> measurement, phase-shifling interferometry, and x-ray extensometry are discussed. Present status and limitations of these technologies are presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015APS..MARZ39008B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015APS..MARZ39008B"><span>Can a <span class="hlt">strain</span> yield a qubit?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Benjamin, Colin</p> <p>2015-03-01</p> <p>A Josepshon qubit is designed via the application of a tensile <span class="hlt">strain</span> to a topological insulator surface, sandwiched between two s-wave superconductors. The <span class="hlt">strain</span> applied leads to a shift in Dirac point without changing the conducting states existing on the surface of a topological insulator. This <span class="hlt">strain</span> applied can be tuned to form a π-junction in such a structure. Combining two such junctions in a ring architecture leads to the ground state of the ring being in a doubly degenerate state- ``0'' and ``1'' states of the qubit. A qubit designed this way is easily controlled via the tunable <span class="hlt">strain</span>. We report on the conditions necessary to design such a qubit. Finally the operating time of a single qubit phase gate is derived. This work was supported by funds from Dept. of Science and Technology (Nanomission), Govt. of India, Grant No. SR/NM/NS-1101/2011.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25817029','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25817029"><span>Survival and activity of individual bioaugmentation <span class="hlt">strains</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Dueholm, Morten S; Marques, Irina G; Karst, Søren M; D'Imperio, Seth; Tale, Vaibhav P; Lewis, Derrick; Nielsen, Per Halkjær; Nielsen, Jeppe Lund</p> <p>2015-06-01</p> <p>Successful application of bioaugmentation for enhanced degradation of environmental pollutants is often limited by the lack of methods to monitor the survival and activity of individual bioaugmentation <span class="hlt">strains</span>. However, recent advancements in sequencing technologies and molecular techniques now allow us to address these limitations. Here a complementing set of general applicable molecular methods are presented that provides detailed information on the performance of individual bioaugmentation <span class="hlt">strains</span> under in situ conditions. The approach involves genome sequencing to establish highly specific qPCR and RT-qPCR tools for cell enumerations and expression of involved genes, stable isotope probing to follow growth on the target compounds and GFP-tagging to visualize the bioaugmentation <span class="hlt">strains</span> directly in samples, all in combination with removal studies of the target compounds. The concept of the approach is demonstrated through a case study involving degradation of aromatic hydrocarbons in activated sludge augmented with the bioaugmentation <span class="hlt">strain</span> Pseudomonas monteilii SB3078.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20050163141','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20050163141"><span><span class="hlt">Strained</span> Hydrocarbons as Potential Hypergolic Fuels</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>2005-01-01</p> <p>A storable combination of high-energy hypergolic fuel and oxidizer is advantageous to the future of reusable launch vehicles (RLVs). The combination will allow an increase in energy per unit volume of fuel and eliminate the need for an external ignition system. <span class="hlt">Strained</span> systems have been studied as potential high-density fuels. Adding hypergolic functional groups, such as amino groups, to these hydrocarbons will potentially allow auto ignition of <span class="hlt">strained</span> systems with hydrogen peroxide. Several straight chain amines and their <span class="hlt">strained</span> counterparts containing an equivalent number of carbon atoms have been purchased and synthesized. These amines provide initial studies to determine the effects of fuel vapor pressure, <span class="hlt">strain</span> energy, fuel miscibility, and amine substitution upon fuel ignition time and hypergolicity with hydrogen peroxide as an oxidizer.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=strain+AND+gauges&id=EJ095175','ERIC'); return false;" href="http://eric.ed.gov/?q=strain+AND+gauges&id=EJ095175"><span>Dynamic Force Measurement with <span class="hlt">Strain</span> Gauges</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Lee, Bruce E.</p> <p>1974-01-01</p> <p>Discusses the use of four <span class="hlt">strain</span> gauges, a Wheatstone bridge, and an oscilloscope to measure forces dynamically. Included is an example of determining the centripetal force of a pendulum in a general physics laboratory. (CC)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19870019450','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19870019450"><span>Thin film <span class="hlt">strain</span> gage development program</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Grant, H. P.; Przybyszewski, J. S.; Anderson, W. L.; Claing, R. G.</p> <p>1983-01-01</p> <p>Sputtered thin-film dynamic <span class="hlt">strain</span> gages of 2 millimeter (0.08 in) gage length and 10 micrometer (0.0004 in) thickness were fabricated on turbojet engine blades and tested in a simulated compressor environment. Four designs were developed, two for service to 600 K (600 F) and two for service to 900 K (1200 F). The program included a detailed study of guidelines for formulating <span class="hlt">strain</span>-gage alloys to achieve superior dynamic and static gage performance. The tests included gage factor, fatigue, temperature cycling, spin to 100,000 G, and erosion. Since the installations are 30 times thinner than conventional wire <span class="hlt">strain</span> gage installations, and any alteration of the aerodynamic, thermal, or structural performance of the blade is correspondingly reduced, dynamic <span class="hlt">strain</span> measurement accuracy higher than that attained with conventional gages is expected. The low profile and good adherence of the thin film elements is expected to result in improved durability over conventional gage elements in engine tests.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1013558','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1013558"><span>Method of transferring <span class="hlt">strained</span> semiconductor structure</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Nastasi, Michael A.; Shao, Lin</p> <p>2009-12-29</p> <p>The transfer of <span class="hlt">strained</span> semiconductor layers from one substrate to another substrate involves depositing a multilayer structure on a substrate having surface contaminants. An interface that includes the contaminants is formed in between the deposited layer and the substrate. Hydrogen atoms are introduced into the structure and allowed to diffuse to the interface. Afterward, the deposited multilayer structure is bonded to a second substrate and is separated away at the interface, which results in transferring a multilayer structure from one substrate to the other substrate. The multilayer structure includes at least one <span class="hlt">strained</span> semiconductor layer and at least one <span class="hlt">strain</span>-induced seed layer. The <span class="hlt">strain</span>-induced seed layer can be optionally etched away after the layer transfer.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19820059659&hterms=Durbin&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DDurbin','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19820059659&hterms=Durbin&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DDurbin"><span>The premixed flame in uniform <span class="hlt">straining</span> flow</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Durbin, P. A.</p> <p>1982-01-01</p> <p>Characteristics of the premixed flame in uniform <span class="hlt">straining</span> flow are investigated by the technique of activation-energy asymptotics. An inverse method is used, which avoids some of the restrictions of previous analyses. It is shown that this method recovers known results for adiabatic flames. New results for flames with heat loss are obtained, and it is shown that, in the presence of finite heat loss, <span class="hlt">straining</span> can extinguish flames. A stability analysis shows that <span class="hlt">straining</span> can suppress the cellular instability of flames with Lewis number less than unity. <span class="hlt">Strain</span> can produce instability of flames with Lewis number greater than unity. A comparison shows quite good agreement between theoretical deductions and experimental observations of Ishizuka, Miyasaka & Law (1981).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/21882791','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/21882791"><span>Heat <span class="hlt">strain</span> during explosive ordnance disposal.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Stewart, Ian B; Rojek, Amanda M; Hunt, Andrew P</p> <p>2011-08-01</p> <p>Bomb technicians perform their work while encapsulated in explosive ordnance disposal suits. Designed primarily for safety, these suits have an unintended consequence of impairing the body's natural mechanisms for heat dissipation. Consequently, bomb technicians are known to experience symptoms of heat illness while performing their work. This research provides the first field based analysis of heat <span class="hlt">strain</span> in bomb technicians. Six participants undertook simulated operational tasks across 2 days of variable climate. All subjects demonstrated high levels of heat <span class="hlt">strain</span> as evidenced by elevated heart rate, core body temperature, and physiological <span class="hlt">strain</span> index. Participants also reported signs and symptoms associated with heat illness. These results were exacerbated by more intense physical activity despite being undertaken in a cooler environment. The universal experience of heat <span class="hlt">strain</span> in this sample has significant implications for the health of bomb technicians and additional research examining methods to improve temperature regulation and performance is warranted.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_22 --> <div id="page_23" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="441"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013NaPho...7...86L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013NaPho...7...86L"><span>Optical physics: Magnetic appeal in <span class="hlt">strained</span> lattice</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lepetit, Thomas</p> <p>2013-02-01</p> <p>Using <span class="hlt">strain</span> to induce a pseudomagnetic field in a photonic lattice at optical frequencies might bring improvements to fields such as photonic crystal fibres, supercontinuum generation and frequency combs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19930081520','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19930081520"><span>The Development of Electrical <span class="hlt">Strain</span> Gages</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>De Forest, A V; Leaderman, H</p> <p>1940-01-01</p> <p>The design, construction, and properties of an electrical-resistance <span class="hlt">strain</span> gage consisting of fine wires molded in a laminated plastic are described. The properties of such gages are discussed and also the problems of molding of wires in plastic materials, temperature compensation, and cementing and removal of the gages. Further work to be carried out on the <span class="hlt">strain</span> gage, together with instrument problems, is discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20050179347&hterms=Adhesives&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DAdhesives','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20050179347&hterms=Adhesives&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DAdhesives"><span>High-Temperature Adhesive <span class="hlt">Strain</span> Gage Developed</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Pereira, J. Michael; Roberts, Gary D.</p> <p>1997-01-01</p> <p>Researchers at the NASA Lewis Research Center have developed a unique <span class="hlt">strain</span> gage and adhesive system for measuring the mechanical properties of polymers and polymer composites at elevated temperatures. This system overcomes some of the problems encountered in using commercial <span class="hlt">strain</span> gages and adhesives. For example, typical commercial <span class="hlt">strain</span> gage adhesives require a postcure at temperatures substantially higher than the maximum test temperature. The exposure of the specimen to this temperature may affect subsequent results, and in some cases may be higher than the glass-transition temperature of the polymer. In addition, although typical commercial <span class="hlt">strain</span> gages can be used for short times at temperatures up to 370 C, their long-term use is limited to 230 C. This precludes their use for testing some high-temperature polyimides near their maximum temperature capability. Lewis' <span class="hlt">strain</span> gage and adhesive system consists of a nonencapsulated, unbacked gage grid that is bonded directly to the polymer after the specimen has been cured but prior to the normal postcure cycle. The gage is applied with an adhesive specially formulated to cure under the specimen postcure conditions. Special handling, mounting, and electrical connection procedures were developed, and a fixture was designed to calibrate each <span class="hlt">strain</span> gage after it was applied to a specimen. A variety of tests was conducted to determine the performance characteristics of the gages at elevated temperatures on PMR-15 neat resin and titanium specimens. For these tests, which included static tension, thermal exposure, and creep tests, the gage and adhesive system performed within normal <span class="hlt">strain</span> gage specifications at 315 C. An example of the performance characteristics of the gage can be seen in the figure, which compares the <span class="hlt">strain</span> gage measurement on a polyimide specimen at 315 C with an extensometer measurement.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3647418','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3647418"><span>Feline Origin of Rotavirus <span class="hlt">Strain</span>, Tunisia, 2008</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Fredj, Mouna Ben Hadj; Heylen, Elisabeth; Zeller, Mark; Fodha, Imene; Benhamida-Rebai, Meriam; Van Ranst, Marc; Matthijnssens, Jelle</p> <p>2013-01-01</p> <p>In Tunisia in 2008, an unusual G6P[9] rotavirus, RVA/human-wt/TUN/17237/2008/G6P[9], rarely found in humans, was detected in a child. To determine the origin of this <span class="hlt">strain</span>, we conducted phylogenetic analyses and found a unique genotype constellation resembling rotaviruses belonging to the feline BA222-like genotype constellation. The <span class="hlt">strain</span> probably resulted from direct cat-to-human transmission. PMID:23631866</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/10161061','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/10161061"><span>Thermographic phosphor <span class="hlt">strain</span> measurements. Final report</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Allison, S.W.; Capps, G.J.; Smith, D.B.; Cates, M.R.; Gleason, J.; Turley, W.D.</p> <p>1994-05-01</p> <p>This report describes the first phase of research aimed at developing a high-temperature <span class="hlt">strain</span> gauge for power equipment use based on materials whose fluorescence characteristics are affected by <span class="hlt">strain</span>. In electric power generating plants, the combined effect of temperature and <span class="hlt">strain</span> on equipment and structures is a critical factor in safe, efficient operation and component lifetime. For the first part of this project, the pressure responses of phosphor and crystalline materials were surveyed. Next, pressure measurements on some promising materials, YVO{sub 4}:Dy and Gd{sub 2}O{sub 2}S:Tb, were performed. The latter phosphor appears to exhibit the greatest change with pressure. Its fluorescence lifetime decreases by a factor of 10 with pressure increase of 20 kbar. In a <span class="hlt">strain</span> test configuration, a tapered sapphire rod compressed a similar phosphor material, La{sub 2}O{sub 2}S:Eu. The intensity level increased, as expected for this material, with compression. Both of the oxysulfide materials possess potential for use in an optical <span class="hlt">strain</span> gauge for temperatures up to at least 300{degrees}C. It is suggested that a mixture of these two materials may be a useful way to obtain the maximum pressure or <span class="hlt">strain</span> sensitivity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AGUFM.H43E1060P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AGUFM.H43E1060P"><span>Colloid <span class="hlt">Straining</span> within Saturated Heterogeneous Porous Media</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Porubcan, A.; Walczak, J.; Xu, S.</p> <p>2008-12-01</p> <p>A thorough understanding of colloid movement in the subsurface system is critical to the assessment of groundwater pollution by pathogenic bacteria and colloid-bound contaminants. It is increasingly recognized that <span class="hlt">straining</span>, a process that occurs when the pore space is too small to allow for a particle's passage, represents an important process in colloid immobilization within groundwater systems. Previously published studies have focused on the kinetics of colloid <span class="hlt">straining</span> within sand packs composed of uniform mineral grains. Natural aquifers, however, are usually characterized by physically heterogeneous sediments. In this study, we conducted column transport experiments with carboxylated latex particles and quartz sand to investigate the impact of sediment texture (i.e., the size distribution of mineral grains) on colloid <span class="hlt">straining</span> kinetics. The quartz sands used in the experiment were thoroughly cleaned and the strong repulsive interactions between colloid particles and quartz sands resulted in minimal physicochemical deposition so the <span class="hlt">straining</span> kinetics can be quantified unambiguously. Sand packs of different textures were prepared by mixing sands of various sizes (mesh sizes of 20-25, 35-40 and 60-70). Our results suggested that the ratio of colloid size and the median sand grain size was insufficient to predict colloid <span class="hlt">straining</span> within heterogeneous sediments. Soil texture, which was related to the size distribution of the sand grains, must be considered. A relationship between colloid <span class="hlt">straining</span> kinetics and the heterogeneity of porous media that can be useful for the prediction of colloid transport within heterogeneous sediments was presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011OptMa..33..408F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011OptMa..33..408F"><span>Flexible photonic crystals for <span class="hlt">strain</span> sensing</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fortes, Luís M.; Gonçalves, M. Clara; Almeida, Rui M.</p> <p>2011-01-01</p> <p>Three-dimensional (3-D) photonic crystals (PCs) have been studied as possible <span class="hlt">strain</span> sensing materials, based on <span class="hlt">strain</span>-induced stop band frequency shifting. Self-assembly of polystyrene microspheres, achieved by sedimentation over a flexible polyimide tape substrate whose surface hydrophilicity was optimized in order to achieve maximum wettability, led to an organized 3-D direct opal template. This was infiltrated with a silica sol-gel solution by dip-coating or by chemical vapour deposition and an inverse opal structure was ultimately obtained by chemical dissolution of the polymer template. The structural and optical properties of these PCs have been studied by scanning electron microscopy (FE-SEM) and UV/visible spectroscopy under variable degrees of <span class="hlt">strain</span>. FE-SEM showed the presence of ordered domains up to ∼30 μm2. A mechano-optical effect was evidenced by <span class="hlt">strain</span>-induced shifting of the photonic stop band peak wavelength of the direct, infiltrated and inverse opals up to 50 nm in transmission mode, due to changes in interplanar spacing upon bending the flexible PCs. Optical response <span class="hlt">strain</span> cycles were studied, suggesting the possible use of these structures in reversible photonic <span class="hlt">strain</span> sensors integrated in sensor/actuator devices.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/6722711','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/6722711"><span>Fermentation studies using Saccharomyces diastaticus yeast <span class="hlt">strains</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Erratt, J.A.; Stewart, G.G.</p> <p>1981-01-01</p> <p>The yeast species, Saccharomyces diastaticus, has the ability to ferment starch and dextrin, because of the extracellular enzyme, glucoamylase, which hydrolyzes the starch/dextrin to glucose. A number of nonallelic genes--DEX 1, DEX 2, and dextrinase B which is allelic to STA 3--have been isolated, which impart to the yeast the ability to ferment dextrin. Various diploid yeast <span class="hlt">strains</span> were constructed, each being either heterozygous or homozygous for the individual dextrinase genes. Using 12 (sup 0) plato hopped wort (30% corn adjunct) under agitated conditions, the fermentation rates of the various diploid yeast <span class="hlt">strains</span> were monitored. A gene-dosage effect was exhibited by yeast <span class="hlt">strains</span> containing DEX 1 or DEX 2, however, not with yeast <span class="hlt">strains</span> containing dextrinase B (STA 3). The fermentation and growth rates and extents were determined under static conditions at 14.4 C and 21 C. With all yeast <span class="hlt">strains</span> containing the dextrinase genes, both fermentation and growth were increased at the higher incubation temperature. Using 30-liter fermentors, beer was produced with the various yeast <span class="hlt">strains</span> containing the dextrinase genes and the physical and organoleptic characteristics of the products were determined. The concentration of glucose in the beer was found to increase during a 3-mo storage period at 21 C, indicating that the glucoamylase from Saccharomyces diastaticus is not inactivated by pasteurization. (Refs. 36).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/902633','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/servlets/purl/902633"><span>Load cell having <span class="hlt">strain</span> gauges of arbitrary location</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Spletzer, Barry</p> <p>2007-03-13</p> <p>A load cell utilizes a plurality of <span class="hlt">strain</span> gauges mounted upon the load cell body such that there are six independent load-<span class="hlt">strain</span> relations. Load is determined by applying the inverse of a load-<span class="hlt">strain</span> sensitivity matrix to a measured <span class="hlt">strain</span> vector. The sensitivity matrix is determined by performing a multivariate regression technique on a set of known loads correlated to the resulting <span class="hlt">strains</span>. Temperature compensation is achieved by configuring the <span class="hlt">strain</span> gauges as co-located orthogonal pairs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/18689636','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/18689636"><span>Pathogenesis of XJ and Romero <span class="hlt">strains</span> of Junin virus in two <span class="hlt">strains</span> of guinea pigs.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Yun, Nadezhda E; Linde, Nathaniel S; Dziuba, Natallia; Zacks, Michele A; Smith, Jeanon N; Smith, Jennifer K; Aronson, Judy F; Chumakova, Olga V; Lander, Heather M; Peters, Clarence J; Paessler, Slobodan</p> <p>2008-08-01</p> <p>Argentine hemorrhagic fever (AHF), a systemic infectious disease caused by infection with Junin virus, affects several organs, and patients can show hematologic, cardiovascular, renal, or neurologic symptoms. We compared the virulence of two Junin virus <span class="hlt">strains</span> in inbred and outbred guinea pigs with the aim of characterizing this animal model better for future vaccine/antiviral efficacy studies. Our data indicate that this passage of the XJ <span class="hlt">strain</span> is attenuated in guinea pigs. In contrast, the Romero <span class="hlt">strain</span> is highly virulent in <span class="hlt">Strain</span> 13 as well as in Hartley guinea pigs, resulting in systemic infection, thrombocytopenia, elevated aspartate aminotransferase levels, and ultimately, uniformly lethal disease. We detected viral antigen in formalin-fixed, paraffin-embedded tissues. Thus, both guinea pig <span class="hlt">strains</span> are useful animal models for lethal Junin virus (Romero <span class="hlt">strain</span>) infection and potentially can be used for preclinical trials in vaccine or antiviral drug development.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22021041','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22021041"><span>Molecular typing of Brucella melitensis endemic <span class="hlt">strains</span> and differentiation from the vaccine <span class="hlt">strain</span> Rev-1.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Noutsios, Georgios T; Papi, Rigini M; Ekateriniadou, Loukia V; Minas, Anastasios; Kyriakidis, Dimitrios A</p> <p>2012-03-01</p> <p>In the present study forty-four Greek endemic <span class="hlt">strains</span> of Br. melitensis and three reference <span class="hlt">strains</span> were genotyped by Multi locus Variable Number Tandem Repeat (ML-VNTR) analysis based on an eight-base pair tandem repeat sequence that was revealed in eight loci of Br. melitensis genome. The forty-four <span class="hlt">strains</span> were discriminated from the vaccine <span class="hlt">strain</span> Rev-1 by Restriction Fragment Length Polymorphism (RFLP) and Denaturant Gradient Gel Electrophoresis (DGGE). The ML-VNTR analysis revealed that endemic, reference and vaccine <span class="hlt">strains</span> are genetically closely related, while most of the loci tested (1, 2, 4, 5 and 7) are highly polymorphic with Hunter-Gaston Genetic Diversity Index (HGDI) values in the range of 0.939 to 0.775. Analysis of ML-VNTRs loci stability through in vitro passages proved that loci 1 and 5 are non stable. Therefore, vaccine <span class="hlt">strain</span> can be discriminated from endemic <span class="hlt">strains</span> by allele's clusters of loci 2, 4, 6 and 7. RFLP and DGGE were also employed to analyse omp2 gene and reveled different patterns among Rev-1 and endemic <span class="hlt">strains</span>. In RFLP, Rev-1 revealed three fragments (282, 238 and 44 bp), while endemic <span class="hlt">strains</span> two fragments (238 and 44 bp). As for DGGE, the electrophoretic mobility of Rev-1 is different from the endemic <span class="hlt">strains</span> due to heterologous binding of DNA chains of omp2a and omp2b gene. Overall, our data show clearly that it is feasible to genotype endemic <span class="hlt">strains</span> of Br. melitensis and differentiate them from vaccine <span class="hlt">strain</span> Rev-1 with ML-VNTR, RFLP and DGGE techniques. These tools can be used for conventional investigations in brucellosis outbreaks.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016RScI...87j2506M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016RScI...87j2506M"><span>On the use of <span class="hlt">strain</span> sensor technologies for <span class="hlt">strain</span> modal analysis: Case studies in aeronautical applications</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Marques dos Santos, Fábio Luis; Peeters, Bart</p> <p>2016-10-01</p> <p>This paper discusses the use of optical fiber Bragg grating (FBG) and piezo <span class="hlt">strain</span> sensors for structural dynamic measurements. For certain industrial applications, there is an interest to use <span class="hlt">strain</span> sensors rather than in combination with accelerometers for experimental modal analysis. Classical electrical <span class="hlt">strain</span> gauges can be used hereto, but other types of <span class="hlt">strain</span> sensors are an interesting alternative with some very specific advantages. This work gives an overview of two types of dynamic <span class="hlt">strain</span> sensors, applied to two industrial applications (a helicopter main rotor blade and an F-16 aircraft), FBG sensors and dynamic piezo <span class="hlt">strain</span> sensors, discussing their use and benefits. Moreover, the concept of <span class="hlt">strain</span> modal analysis is introduced and it is shown how it can be beneficial to apply <span class="hlt">strain</span> measurements to experimental modal analysis. Finally, experimental results for the two applications are shown, with an experimental modal analysis carried out on the helicopter main rotor blade using FBG sensors and a similar experiment is done with the aircraft but using piezo <span class="hlt">strain</span> sensors instead.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26360021','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26360021"><span>Genome-Wide Transcription Study of Cryptococcus neoformans H99 Clinical <span class="hlt">Strain</span> versus Environmental <span class="hlt">Strains</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Movahed, Elaheh; Munusamy, Komathy; Tan, Grace Min Yi; Looi, Chung Yeng; Tay, Sun Tee; Wong, Won Fen</p> <p>2015-01-01</p> <p>The infection of Cryptococcus neoformans is acquired through the inhalation of desiccated yeast cells and basidiospores originated from the environment, particularly from bird's droppings and decaying wood. Three environmental <span class="hlt">strains</span> of C. neoformans originated from bird droppings (H4, S48B and S68B) and C. neoformans reference clinical <span class="hlt">strain</span> (H99) were used for intranasal infection in C57BL/6 mice. We showed that the H99 <span class="hlt">strain</span> demonstrated higher virulence compared to H4, S48B and S68B <span class="hlt">strains</span>. To examine if gene expression contributed to the different degree of virulence among these <span class="hlt">strains</span>, a genome-wide microarray study was performed to inspect the transcriptomic profiles of all four <span class="hlt">strains</span>. Our results revealed that out of 7,419 genes (22,257 probes) examined, 65 genes were significantly up-or down-regulated in H99 versus H4, S48B and S68B <span class="hlt">strains</span>. The up-regulated genes in H99 <span class="hlt">strain</span> include Hydroxymethylglutaryl-CoA synthase (MVA1), Mitochondrial matrix factor 1 (MMF1), Bud-site-selection protein 8 (BUD8), High affinity glucose transporter 3 (SNF3) and Rho GTPase-activating protein 2 (RGA2). Pathway annotation using DAVID bioinformatics resource showed that metal ion binding and sugar transmembrane transporter activity pathways were highly expressed in the H99 <span class="hlt">strain</span>. We suggest that the genes and pathways identified may possibly play crucial roles in the fungal pathogenesis.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26063842','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26063842"><span>Bone <span class="hlt">strain</span> magnitude is correlated with bone <span class="hlt">strain</span> rate in tetrapods: implications for models of mechanotransduction.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Aiello, B R; Iriarte-Diaz, J; Blob, R W; Butcher, M T; Carrano, M T; Espinoza, N R; Main, R P; Ross, C F</p> <p>2015-07-07</p> <p>Hypotheses suggest that structural integrity of vertebrate bones is maintained by controlling bone <span class="hlt">strain</span> magnitude via adaptive modelling in response to mechanical stimuli. Increased tissue-level <span class="hlt">strain</span> magnitude and rate have both been identified as potent stimuli leading to increased bone formation. Mechanotransduction models hypothesize that osteocytes sense bone deformation by detecting fluid flow-induced drag in the bone's lacunar-canalicular porosity. This model suggests that the osteocyte's intracellular response depends on fluid-flow rate, a product of bone <span class="hlt">strain</span> rate and gradient, but does not provide a mechanism for detection of <span class="hlt">strain</span> magnitude. Such a mechanism is necessary for bone modelling to adapt to loads, because <span class="hlt">strain</span> magnitude is an important determinant of skeletal fracture. Using <span class="hlt">strain</span> gauge data from the limb bones of amphibians, reptiles, birds and mammals, we identified strong correlations between <span class="hlt">strain</span> rate and magnitude across clades employing diverse locomotor styles and degrees of rhythmicity. The breadth of our sample suggests that this pattern is likely to be a common feature of tetrapod bone loading. Moreover, finding that bone <span class="hlt">strain</span> magnitude is encoded in <span class="hlt">strain</span> rate at the tissue level is consistent with the hypothesis that it might be encoded in fluid-flow rate at the cellular level, facilitating bone adaptation via mechanotransduction.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4567374','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4567374"><span>Genome-Wide Transcription Study of Cryptococcus neoformans H99 Clinical <span class="hlt">Strain</span> versus Environmental <span class="hlt">Strains</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Movahed, Elaheh; Munusamy, Komathy; Tan, Grace Min Yi; Looi, Chung Yeng; Tay, Sun Tee; Wong, Won Fen</p> <p>2015-01-01</p> <p>The infection of Cryptococcus neoformans is acquired through the inhalation of desiccated yeast cells and basidiospores originated from the environment, particularly from bird’s droppings and decaying wood. Three environmental <span class="hlt">strains</span> of C. neoformans originated from bird droppings (H4, S48B and S68B) and C. neoformans reference clinical <span class="hlt">strain</span> (H99) were used for intranasal infection in C57BL/6 mice. We showed that the H99 <span class="hlt">strain</span> demonstrated higher virulence compared to H4, S48B and S68B <span class="hlt">strains</span>. To examine if gene expression contributed to the different degree of virulence among these <span class="hlt">strains</span>, a genome-wide microarray study was performed to inspect the transcriptomic profiles of all four <span class="hlt">strains</span>. Our results revealed that out of 7,419 genes (22,257 probes) examined, 65 genes were significantly up-or down-regulated in H99 versus H4, S48B and S68B <span class="hlt">strains</span>. The up-regulated genes in H99 <span class="hlt">strain</span> include Hydroxymethylglutaryl-CoA synthase (MVA1), Mitochondrial matrix factor 1 (MMF1), Bud-site-selection protein 8 (BUD8), High affinity glucose transporter 3 (SNF3) and Rho GTPase-activating protein 2 (RGA2). Pathway annotation using DAVID bioinformatics resource showed that metal ion binding and sugar transmembrane transporter activity pathways were highly expressed in the H99 <span class="hlt">strain</span>. We suggest that the genes and pathways identified may possibly play crucial roles in the fungal pathogenesis. PMID:26360021</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19850013288','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19850013288"><span>Thin film <span class="hlt">strain</span> transducer. [suitable for in-flight measurement of scientific balloon <span class="hlt">strain</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Rand, J. L. (Inventor)</p> <p>1985-01-01</p> <p>A <span class="hlt">strain</span> transducer system and process for making same is disclosed wherein a beryllium-copper ring having four <span class="hlt">strain</span> gages disposed thereon is electrically connected in Wheatstone bridge fashion to output instrumentation. Tabs are bonded to a balloon or like surface with <span class="hlt">strain</span> on the surface causing bending of the ring and providing an electrical signal through the gages proportional to the surface <span class="hlt">strain</span>. A figure is provided which illustrates a pattern of a one-half ring segment as placed on a sheet of beryllium-copper for chem-mill etch formation, prior to bending and welding of a pair of the segments to form a ring structure.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/762874','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/762874"><span>Imploding Liner Material Strength Measurements at High-<span class="hlt">Strain</span> and High <span class="hlt">Strain</span> Rate</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Bartsch, R.R.; Lee, H.; Holtkamp, D.; Wright, B.; Stokes, J.; Morgan, D.; Anderson, W.; Broste, W.</p> <p>1998-10-18</p> <p>Imploding, cylindrical liners provide a unique, shockless means of simultaneously accessing high <span class="hlt">strain</span> and high-<span class="hlt">strain</span>-rate for measurement of strength of materials in plastic flow. The radial convergence in the liner geometry results in the liner thickening as the circumference becomes smaller. <span class="hlt">Strains</span> of up to {approximately}1.25 and <span class="hlt">strain</span> rates of up to {approximately}10{sup 6} sec{sup -1} can be readily achieved in a material sample placed inside of an aluminum driver liner, using the Pegasus II capacitor bank. This provides yield strength data at conditions where none presently exists. The heating from work done against the yield strength is measured with multichannel pyrometry from infrared radiation emitted by the material sample. The temperature data as a function of liner position are unfolded to give the yield strength along the <span class="hlt">strain</span>, <span class="hlt">strain</span>-rate trajectory. Proper design of the liner and sample configuration ensures that the current diffused into the sample adds negligible heating. An important issue, in this type of temperature measurement, is shielding of the pickup optics from other sources of radiation. At <span class="hlt">strains</span> greater than those achievable on Pegasus, e.g. the LANL Atlas facility, some materials may be heated all the way to melt by this process. Recent data on 6061-T6 Aluminum will be compared with an existing model for <span class="hlt">strain</span> and <span class="hlt">strain</span>-rate heating. The liner configuration and pyrometry diagnostic will also be discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/960184','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/960184"><span>Stress-<span class="hlt">Strain</span> Relation and <span class="hlt">strain</span>-Induced Crystallization in Rubber</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Toki,S.</p> <p>2006-01-01</p> <p>Rubber is composed of flexible chains and network points. Theory of rubber elasticity succeeds to elucidate stress-<span class="hlt">strain</span> relation of rubber using the inverse Langevin equation of entropy modulus. However, actual rubber is much different from ideal networks composed of ideal rubber chains. Network points may not distribute homogeneously and the molecular weight between two network points may show wide distribution. Flexible chains show <span class="hlt">strain</span>-induced crystallization. Recent synchrotron X-ray and simultaneous stress-<span class="hlt">strain</span> measurements reveal that <span class="hlt">strain</span>-induced crystallization reduces the stress by increasing the length of molecules along the stretching direction. Also, <span class="hlt">strain</span>-induced crystals are created not at the middle of the network points, but at the close location to the network points. The hybrid structure of <span class="hlt">strain</span>-induced crystallites and network points may be stronger than network points alone. Therefore, <span class="hlt">strain</span> induced crystallization may increase the tensile strength of rubber by two mechanisms, they are, increase of elongation at break and reinforcement of network points. Natural rubber has biotic network points in nature. After vulcanization, the biotic network may contribute the superior toughness of NR, comparing to IR. Carbon filled NR also shows <span class="hlt">strain</span> induced crystallization. In order to acquire high tensile strength, molecules should have higher flexibility to perform <span class="hlt">strain</span> induced crystallization by selecting a kind of carbon blacks, an accelerator and a curing condition.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4590470','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4590470"><span>Bone <span class="hlt">strain</span> magnitude is correlated with bone <span class="hlt">strain</span> rate in tetrapods: implications for models of mechanotransduction</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Aiello, B. R.; Iriarte-Diaz, J.; Blob, R. W.; Butcher, M. T.; Carrano, M. T.; Espinoza, N. R.; Main, R. P.; Ross, C. F.</p> <p>2015-01-01</p> <p>Hypotheses suggest that structural integrity of vertebrate bones is maintained by controlling bone <span class="hlt">strain</span> magnitude via adaptive modelling in response to mechanical stimuli. Increased tissue-level <span class="hlt">strain</span> magnitude and rate have both been identified as potent stimuli leading to increased bone formation. Mechanotransduction models hypothesize that osteocytes sense bone deformation by detecting fluid flow-induced drag in the bone's lacunar–canalicular porosity. This model suggests that the osteocyte's intracellular response depends on fluid-flow rate, a product of bone <span class="hlt">strain</span> rate and gradient, but does not provide a mechanism for detection of <span class="hlt">strain</span> magnitude. Such a mechanism is necessary for bone modelling to adapt to loads, because <span class="hlt">strain</span> magnitude is an important determinant of skeletal fracture. Using <span class="hlt">strain</span> gauge data from the limb bones of amphibians, reptiles, birds and mammals, we identified strong correlations between <span class="hlt">strain</span> rate and magnitude across clades employing diverse locomotor styles and degrees of rhythmicity. The breadth of our sample suggests that this pattern is likely to be a common feature of tetrapod bone loading. Moreover, finding that bone <span class="hlt">strain</span> magnitude is encoded in <span class="hlt">strain</span> rate at the tissue level is consistent with the hypothesis that it might be encoded in fluid-flow rate at the cellular level, facilitating bone adaptation via mechanotransduction. PMID:26063842</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016APLM....4f4107S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016APLM....4f4107S"><span>Elastocaloric cooling processes: The influence of material <span class="hlt">strain</span> and <span class="hlt">strain</span> rate on efficiency and temperature span</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Schmidt, Marvin; Schütze, Andreas; Seelecke, Stefan</p> <p>2016-06-01</p> <p>This paper discusses the influence of material <span class="hlt">strain</span> and <span class="hlt">strain</span> rate on efficiency and temperature span of elastocaloric cooling processes. The elastocaloric material, a newly developed quaternary Ni-Ti-Cu-V alloy, is characterized at different maximum <span class="hlt">strains</span> and <span class="hlt">strain</span> rates. The experiments are performed with a specially designed test setup, which enables the measurement of mechanical and thermal process parameters. The material efficiency is compared to the efficiency of the Carnot process at equivalent thermal operation conditions. This method allows for a direct comparison of the investigated material with other caloric materials.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_23 --> <div id="page_24" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="461"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/305920','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/305920"><span>The influence of <span class="hlt">strain</span> rate and hydrogen on the plane-<span class="hlt">strain</span> ductility of Zircaloy cladding</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Link, T.M.; Motta, A.T.; Koss, D.A.</p> <p>1998-03-01</p> <p>The authors studied the ductility of unirradiated Zircaloy-4 cladding under loading conditions prototypical of those found in reactivity-initiated accidents (RIA), i.e.: near plane-<span class="hlt">strain</span> deformation in the hoop direction (transverse to the cladding axis) at room temperature and 300 C and high <span class="hlt">strain</span> rates. To conduct these studies, they developed a specimen configuration in which near plane-<span class="hlt">strain</span> deformation is achieved in the gage section, and a testing methodology that allows one to determine both the limit <span class="hlt">strain</span> at the onset of localized necking and the fracture <span class="hlt">strain</span>. The experiments indicate that there is little effect of <span class="hlt">strain</span> rate (10{sup {minus}3} to 10{sup 2} s{sup {minus}1}) on the ductility of unhydrided Zircaloy tubing deformed under near plane-<span class="hlt">strain</span> conditions at either room temperature or 300 C. Preliminary experiments on cladding containing 190 ppm hydrogen show only a small loss of fracture <span class="hlt">strain</span> but no clear effect on limit <span class="hlt">strain</span>. The experiments also indicate that there is a significant loss of Zircaloy ductility when surface flaws are present in the form of thickness imperfections.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://dx.doi.org/10.1785/0220160155','USGSPUBS'); return false;" href="https://dx.doi.org/10.1785/0220160155"><span>Dynamic <span class="hlt">strains</span> for earthquake source characterization</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Barbour, Andrew; Crowell, Brendan W</p> <p>2017-01-01</p> <p>Strainmeters measure elastodynamic deformation associated with earthquakes over a broad frequency band, with detection characteristics that complement traditional instrumentation, but they are commonly used to study slow transient deformation along active faults and at subduction zones, for example. Here, we analyze dynamic <span class="hlt">strains</span> at Plate Boundary Observatory (PBO) borehole strainmeters (BSM) associated with 146 local and regional earthquakes from 2004–2014, with magnitudes from M 4.5 to 7.2. We find that peak values in seismic <span class="hlt">strain</span> can be predicted from a general regression against distance and magnitude, with improvements in accuracy gained by accounting for biases associated with site–station effects and source–path effects, the latter exhibiting the strongest influence on the regression coefficients. To account for the influence of these biases in a general way, we include crustal‐type classifications from the CRUST1.0 global velocity model, which demonstrates that high‐frequency <span class="hlt">strain</span> data from the PBO BSM network carry information on crustal structure and fault mechanics: earthquakes nucleating offshore on the Blanco fracture zone, for example, generate consistently lower dynamic <span class="hlt">strains</span> than earthquakes around the Sierra Nevada microplate and in the Salton trough. Finally, we test our dynamic <span class="hlt">strain</span> prediction equations on the 2011 M 9 Tohoku‐Oki earthquake, specifically continuous <span class="hlt">strain</span> records derived from triangulation of 137 high‐rate Global Navigation Satellite System Earth Observation Network stations in Japan. Moment magnitudes inferred from these data and the <span class="hlt">strain</span> model are in agreement when Global Positioning System subnetworks are unaffected by spatial aliasing.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/20215607','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/20215607"><span>Volume <span class="hlt">strain</span> within the Geysers geothermal field</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Mossop, Antony; Segall, Paul</p> <p>1999-12-10</p> <p>During the 1970s and 1980s. The Geysers geothermal region was rapidly developed as a site of geothermal power production. The likelihood that this could cause significant <span class="hlt">strain</span> within the reservoir, with corresponding surface displacements, led to a series of deformation monitoring surveys. In 1973, 1975, 1977, and 1980, The Geysers region was surveyed using first-order, class I, spirit leveling. In 1994, 1995, and 1996, many of the leveling control monuments were resurveyed using high-precision Global Positioning System receivers. The two survey methods are reconciled using the GEOID96 geoid model. The displacements are inverted to determine volume <span class="hlt">strain</span> within the reservoir. For the period 1980-1994, peak volume <span class="hlt">strains</span> in excess of 5x10{sup -4} are imaged. There is an excellent correlation between the observed changes in reservoir steam pressures and the imaged volume <span class="hlt">strain</span>. If reservoir pressure changes are inducing volume <span class="hlt">strain</span>, then the reservoir quasi-static bulk modulus K must be <4.6x10{sup 9} Pa. However, seismic velocities indicate a much stiffer reservoir with K=3.4x10{sup 10} Pa. This apparent discrepancy is shown to be consistent with predicted frequency dependence in K for fractured and water-saturated rock. Inversion of surface deformation data therefore appears to be a powerful method for imaging pressure change within the body of the reservoir. Correlation between induced seismicity at The Geysers and volume <span class="hlt">strain</span> is observed. However, earthquake distribution does not appear to have a simple relationship with volume <span class="hlt">strain</span> rate. (c) 1999 American Geophysical Union.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/17093023','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/17093023"><span><span class="hlt">Strain</span>-specific single-nucleotide polymorphism assays for the Bacillus anthracis Ames <span class="hlt">strain</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Van Ert, Matthew N; Easterday, W Ryan; Simonson, Tatum S; U'Ren, Jana M; Pearson, Talima; Kenefic, Leo J; Busch, Joseph D; Huynh, Lynn Y; Dukerich, Megan; Trim, Carla B; Beaudry, Jodi; Welty-Bernard, Amy; Read, Timothy; Fraser, Claire M; Ravel, Jacques; Keim, Paul</p> <p>2007-01-01</p> <p>Highly precise diagnostics and forensic assays can be developed through a combination of evolutionary analysis and the exhaustive examination of genomic sequences. In Bacillus anthracis, whole-genome sequencing efforts revealed ca. 3,500 single-nucleotide polymorphisms (SNPs) among eight different <span class="hlt">strains</span> and evolutionary analysis provides the identification of canonical SNPs. We have previously shown that SNPs are highly evolutionarily stable, and the clonal nature of B. anthracis makes them ideal signatures for subtyping this pathogen. Here we identified SNPs that define the lineage of B. anthracis that contains the Ames <span class="hlt">strain</span>, the <span class="hlt">strain</span> used in the 2001 bioterrorist attacks in the United States. Sequencing and real-time PCR were used to validate these SNPs across B. anthracis <span class="hlt">strains</span>, including (i) 88 globally and genetically diverse isolates; (ii) isolates that were shown to be genetic relatives of the Ames <span class="hlt">strain</span> by multiple-locus variable number tandem repeat analysis (MLVA); and (iii) several different lab stocks of the Ames <span class="hlt">strain</span>, including a clinical isolate from the 2001 letter attack. Six SNPs were found to be highly specific for the Ames <span class="hlt">strain</span>; four on the chromosome, one on the pX01 plasmid, and one on the pX02 plasmid. All six SNPs differentiated the B. anthracis Ames <span class="hlt">strain</span> from the 88 unique B. anthracis <span class="hlt">strains</span>, while five of the six separated Ames from its close genetic relatives. The use of these SNPs coupled with real-time PCR allows specific and sensitive (<100 fg of template DNA) identification of the Ames <span class="hlt">strain</span>. This evolutionary and genomics-based approach provides an effective means for the discovery of <span class="hlt">strain</span>-specific SNPs in B. anthracis.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19810062035&hterms=behavior+analysis&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dbehavior%2Banalysis','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19810062035&hterms=behavior+analysis&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dbehavior%2Banalysis"><span>Analysis of the tensile stress-<span class="hlt">strain</span> behavior of elastomers at constant <span class="hlt">strain</span> rates. I - Criteria for separability of the time and <span class="hlt">strain</span> effects</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hong, S. D.; Fedors, R. F.; Schwarzl, F.; Moacanin, J.; Landel, R. F.</p> <p>1981-01-01</p> <p>A theoretical analysis of the tensile stress-<span class="hlt">strain</span> relation of elastomers at constant <span class="hlt">strain</span> rate is presented which shows that the time and the stress effect are separable if the experimental time scale coincides with a segment of the relaxation modulus that can be described by a single power law. It is also shown that time-<span class="hlt">strain</span> separability is valid if the <span class="hlt">strain</span> function is linearly proportional to the Cauchy <span class="hlt">strain</span>, and that when time-<span class="hlt">strain</span> separability holds, two <span class="hlt">strain</span>-dependent quantities can be obtained experimentally. In the case where time and <span class="hlt">strain</span> effect are not separable, superposition can be achieved only by using temperature and <span class="hlt">strain</span>-dependent shift factors.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3942497','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3942497"><span>The Effect of Ivermectin in Seven <span class="hlt">Strains</span> of Aedes aegypti (Diptera: Culicidae) Including a Genetically Diverse Laboratory <span class="hlt">Strain</span> and Three Permethrin Resistant <span class="hlt">Strains</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Deus, K. M.; Saavedra-rodriguez, K.; Butters, M. P.; Black, W. C.; Foy, B. D.</p> <p>2014-01-01</p> <p>Seven different <span class="hlt">strains</span> of Aedes aegypti (L.), including a genetically diverse laboratory <span class="hlt">strain</span>, three laboratory-selected permethrin-resistant <span class="hlt">strains</span>, a standard reference <span class="hlt">strain</span>, and two recently colonized <span class="hlt">strains</span> were fed on human blood containing various concentrations of ivermectin. Ivermectin reduced adult survival, fecundity, and hatch rate of eggs laid by ivermectin-treated adults in all seven <span class="hlt">strains</span>. The LC50 of ivermectin for adults and the concentration that prevented 50% of eggs from hatching was calculated for all <span class="hlt">strains</span>. Considerable variation in adult survival after an ivermectin-bloodmeal occurred among <span class="hlt">strains</span>, and all three permethrin-resistant <span class="hlt">strains</span> were significantly less susceptible to ivermectin than the standard reference <span class="hlt">strain</span>. The hatch rate after an ivermectin bloodmeal was less variable among <span class="hlt">strains</span>, and only one of the permethrin-resistant <span class="hlt">strains</span> differed significantly from the standard reference <span class="hlt">strain</span>. Our studies suggest that ivermectin induces adult mortality and decreases the hatch rate of eggs through different mechanisms. A correlation analysis of log-transformed LC50 among <span class="hlt">strains</span> suggests that permethrin and ivermectin cross-resistance may occur. PMID:22493855</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhDT.......536S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhDT.......536S"><span>Anisotropic nature of radially <span class="hlt">strained</span> metal tubes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Strickland, Julie N.</p> <p></p> <p>Metal pipes are sometimes swaged by a metal cone to enlarge them, which increases the <span class="hlt">strain</span> in the material. The amount of <span class="hlt">strain</span> is important because it affects the burst and collapse strength. Burst strength is the amount of internal pressure that a pipe can withstand before failure, while collapse strength is the amount of external pressure that a pipe can withstand before failure. If the burst or collapse strengths are exceeded, the pipe may fracture, causing critical failure. Such an event could cost the owners and their customers millions of dollars in clean up, repair, and lost time, in addition to the potential environmental damage. Therefore, a reliable way of estimating the burst and collapse strength of <span class="hlt">strained</span> pipe is desired and valuable. The sponsor currently rates <span class="hlt">strained</span> pipes using the properties of raw steel, because those properties are easily measured (for example, yield strength). In the past, the engineers assumed that the metal would be work-hardened when swaged, so that yield strength would increase. However, swaging introduces anisotropic <span class="hlt">strain</span>, which may decrease the yield strength. This study measured the yield strength of <span class="hlt">strained</span> material in the transverse and axial direction and compared them to raw material, to determine the amount of anisotropy. This information will be used to more accurately determine burst and collapse ratings for <span class="hlt">strained</span> pipes. More accurate ratings mean safer products, which will minimize risk for the sponsor's customers. Since the <span class="hlt">strained</span> metal has a higher yield strength than the raw material, using the raw yield strength to calculate burst and collapse ratings is a conservative method. The metal has even higher yield strength after <span class="hlt">strain</span> aging, which indicates that the stresses are relieved. Even with the 12% anisotropy in the <span class="hlt">strained</span> and 9% anisotropy in the <span class="hlt">strain</span> aged specimens, the raw yield strengths are lower and therefore more conservative. I recommend that the sponsor continue using the raw</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/11874722','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/11874722"><span>Growth <span class="hlt">strain</span> in coconut palm trees.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Huang, Yan S; Chen, Shin S; Lin, Tsan P; Chen, Yuh S</p> <p>2002-03-01</p> <p>Until recently, growth stress studies have been made only on coniferous and dicotyledonous trees. Growth stress of trees is thought to be initiated in newly formed secondary xylem cells. This stress can accumulate for years and is distributed inside the trunk. Major characteristics of the trunk of monocotyledonous trees include numerous vascular bundles scattered inside the ground tissue and the lack of secondary growth for enlarging the diameter of the trunk. We used the <span class="hlt">strain</span> gauge method to measure the released growth <span class="hlt">strain</span> of the monocotyledonous woody palm, coconut (Cocos nucifera L.), and to investigate the surface growth <span class="hlt">strain</span> of the trunk and central cylinder at different trunk heights. The internal <span class="hlt">strains</span> of both vertical and leaning trunks were measured and compared with those of coniferous and dicotyledonous trees. We found that tensile stress existed longitudinally on the surface of vertically growing trunks, whereas compression stress was found at the bending position of leaning trunks. Compression stress was found in the outer part of the central cylinder, whereas tensile stress is generally found in the outer part of the trunk in coniferous and dicotyledonous trees. The distribution of <span class="hlt">strain</span> in the palm trunk is similar to that of compression wood of the leaning trunk of a conifer. Specific gravity was greater in the outer part of the trunk than in the inner part of the trunk. This difference may be related to the distribution of growth stress.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1015378','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1015378"><span>Brittle superconducting magnets: an equivilent <span class="hlt">strain</span> model</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Barzi, E.; Danuso, M.</p> <p>2010-08-01</p> <p>To exceed fields of 10 T in accelerator magnets, brittle superconductors like A15 Nb{sub 3}Sn and Nb{sub 3}Al or ceramic High Temperature Superconductors have to be used. For such brittle superconductors it is not their maximum tensile yield stress that limits their structural resistance as much as <span class="hlt">strain</span> values that provoke deformations in their delicate lattice, which in turn affect their superconducting properties. Work on the sensitivity of Nb{sub 3}Sn cables to <span class="hlt">strain</span> has been conducted in a number of stress states, including uniaxial and multi-axial, producing usually different results. This has made the need of a constituent design criterion imperative for magnet builders. In conventional structural problems an equivalent stress model is typically used to verify mechanical soundness. In the superconducting community a simple scalar equivalent <span class="hlt">strain</span> to be used in place of an equivalent stress would be an extremely useful tool. As is well known in fundamental mechanics, there is not one single way to reduce a multiaxial <span class="hlt">strain</span> state as represented by a 2nd order tensor to a scalar. The conceptual experiment proposed here will help determine the best scalar representation to use in the identification of an equivalent <span class="hlt">strain</span> model.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19860008318','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19860008318"><span>Closure of fatigue cracks at high <span class="hlt">strains</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Iyyer, N. S.; Dowling, N. E.</p> <p>1985-01-01</p> <p>Experiments were conducted on smooth specimens to study the closure behavior of short cracks at high cyclic <span class="hlt">strains</span> under completely reversed cycling. Testing procedures and methodology, and closure measurement techniques, are described in detail. The <span class="hlt">strain</span> levels chosen for the study cover from predominantly elastic to grossly plastic <span class="hlt">strains</span>. Crack closure measurements are made at different crack lengths. The study reveals that, at high <span class="hlt">strains</span>, cracks close only as the lowest stress level in the cycle is approached. The crack opening is observed to occur in the compressive part of the loading cycle. The applied stress needed to open a short crack under high <span class="hlt">strain</span> is found to be less than for cracks under small scale yielding. For increased plastic deformations, the value of sigma sub op/sigma sub max is observed to decrease and approaches the value of R. Comparison of the experimental results with existing analysis is made and indicates the limitations of the small scale yielding approach where gross plastic deformation behavior occurs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22398929','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22398929"><span>Secretome analysis of Clostridium difficile <span class="hlt">strains</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Boetzkes, Alexander; Felkel, Katharina Wiebke; Zeiser, Johannes; Jochim, Nelli; Just, Ingo; Pich, Andreas</p> <p>2012-08-01</p> <p>Clostridium difficile causes infections ranging from mild C. difficile-associated diarrhea to severe pseudomembranous colitis. Since 2003 new hypervirulent C. difficile <span class="hlt">strains</span> (PCR ribotype 027) emerged characterized by a dramatically increased mortality. The secretomes of the three C. difficile <span class="hlt">strains</span> CDR20291, CD196, and CD630 were analyzed and compared. Proteins were separated and analyzed by means of SDS--PAGE and LC-MS. MS data were analyzed using Mascot and proteins were checked for export signals with SecretomeP and SignalP. LC-MS analysis revealed 158 different proteins in the supernatant of C. difficile. Most of the identified proteins originate from the cytoplasm. Thirty-two proteins in CDR20291, 36 in CD196 and 26 in CD630 were identified to be secreted by C. difficile <span class="hlt">strains</span>. Those were mainly S-layer proteins, substrate-binding proteins of ABC-transporters, cell wall hydrolases, pilin and unknown hypothetical proteins. Toxin A and toxin B were identified after growth in brain heart infusion medium using immunological techniques. The ADP-ribosyltransferase-binding component protein, which is a part of the binary toxin CDT, was only identified in the hypervirulent ribotype 027 <span class="hlt">strains</span>. Further proteins that are secreted specifically by hypervirulent <span class="hlt">strains</span> were identified.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3575016','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3575016"><span>Fast flexible electronics with <span class="hlt">strained</span> silicon nanomembranes</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Zhou, Han; Seo, Jung-Hun; Paskiewicz, Deborah M.; Zhu, Ye; Celler, George K.; Voyles, Paul M.; Zhou, Weidong; Lagally, Max G.; Ma, Zhenqiang</p> <p>2013-01-01</p> <p>Fast flexible electronics operating at radio frequencies (>1 GHz) are more attractive than traditional flexible electronics because of their versatile capabilities, dramatic power savings when operating at reduced speed and broader spectrum of applications. Transferrable single-crystalline Si nanomembranes (SiNMs) are preferred to other materials for flexible electronics owing to their unique advantages. Further improvement of Si-based device speed implies significant technical and economic advantages. While the mobility of bulk Si can be enhanced using <span class="hlt">strain</span> techniques, implementing these techniques into transferrable single-crystalline SiNMs has been challenging and not demonstrated. The past approach presents severe challenges to achieve effective doping and desired material topology. Here we demonstrate the combination of <span class="hlt">strained</span>- NM-compatible doping techniques with self-sustained-<span class="hlt">strain</span> sharing by applying a <span class="hlt">strain</span>-sharing scheme between Si and SiGe multiple epitaxial layers, to create <span class="hlt">strained</span> print-transferrable SiNMs. We demonstrate a new speed record of Si-based flexible electronics without using aggressively scaled critical device dimensions. PMID:23416347</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/25111022','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/25111022"><span>Genomics of Clostridium botulinum group III <span class="hlt">strains</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Sakaguchi, Yoshihiko; Suzuki, Tomonori; Yamamoto, Yumiko; Nishikawa, Atsushi; Oguma, Keiji</p> <p>2015-05-01</p> <p>In Clostridium botulinum, the characteristics of type C and D <span class="hlt">strains</span> are quite different from other types, and they are classified as group III. They produce C2 binary toxin and C3 exoenzyme in addition to type C and D neurotoxins. Two different phages and many plasmids are identified in the organisms. The genes of neurotoxin and C3 exoenzyme are converted from toxigenic <span class="hlt">strains</span> to non-toxigenic <span class="hlt">strains</span> by the specific bacteriophages (phages), whereas, the C2 toxin gene is carried by large or small plasmids. Classification of type C and D <span class="hlt">strains</span> has been in confusion because 1) antigenicity of type C and D neurotoxins is complex, 2) the cells produce two types of toxins, neurotoxin and C2 toxin, and 3) some non-toxigenic <span class="hlt">strains</span> can be converted to produce C or D neurotoxin by the infection with phages. Until now, entire nucleotide sequences of cell chromosomes, phages, and plasmids have been determined. Since both genetic and protein-chemical analyses have been clarifying the above confusions, these data are reviewed historically.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/27585446','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/27585446"><span>Computer modelling of bone's adaptation: the role of normal <span class="hlt">strain</span>, shear <span class="hlt">strain</span> and fluid flow.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Tiwari, Abhishek Kumar; Prasad, Jitendra</p> <p>2017-04-01</p> <p>Bone loss is a serious health problem. In vivo studies have found that mechanical stimulation may inhibit bone loss as elevated <span class="hlt">strain</span> in bone induces osteogenesis, i.e. new bone formation. However, the exact relationship between mechanical environment and osteogenesis is less clear. Normal <span class="hlt">strain</span> is considered as a prime stimulus of osteogenic activity; however, there are some instances in the literature where osteogenesis is observed in the vicinity of minimal normal <span class="hlt">strain</span>, specifically near the neutral axis of bending in long bones. It suggests that osteogenesis may also be induced by other or secondary components of mechanical environment such as shear <span class="hlt">strain</span> or canalicular fluid flow. As it is evident from the literature, shear <span class="hlt">strain</span> and fluid flow can be potent stimuli of osteogenesis. This study presents a computational model to investigate the roles of these stimuli in bone adaptation. The model assumes that bone formation rate is roughly proportional to the normal, shear and fluid shear <span class="hlt">strain</span> energy density above their osteogenic thresholds. In vivo osteogenesis due to cyclic cantilever bending of a murine tibia has been simulated. The model predicts results close to experimental findings when normal <span class="hlt">strain</span>, and shear <span class="hlt">strain</span> or fluid shear were combined. This study also gives a new perspective on the relation between osteogenic potential of micro-level fluid shear and that of macro-level bending shear. Attempts to establish such relations among the components of mechanical environment and corresponding osteogenesis may ultimately aid in the development of effective approaches to mitigating bone loss.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015CPL...625...69R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015CPL...625...69R"><span><span class="hlt">Strain</span> in <span class="hlt">strain</span>-free benzenoid hydrocarbons: The case of phenanthrene</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Radenković, Slavko; Gutman, Ivan; Đorđević, Slađana</p> <p>2015-04-01</p> <p>Benzenoid molecules possessing bays are traditionally considered as '<span class="hlt">strain</span>-free'. Yet, repulsion between the two bay H-atoms affects the length of the near-lying carbon-carbon bonds. A method is developed to estimate the energy of this <span class="hlt">strain</span>. In the case of phenanthrene its value was found to be about 7 kJ/mol.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4306125','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4306125"><span>MRI-based <span class="hlt">strain</span> and <span class="hlt">strain</span> rate analysis of left ventricle: a modified hierarchical transformation model</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p></p> <p>2015-01-01</p> <p>Background Different from other indicators of cardiac function, such as ejection fraction and transmitral early diastolic velocity, myocardial <span class="hlt">strain</span> is promising to capture subtle alterations that result from early diseases of the myocardium. In order to extract the left ventricle (LV) myocardial <span class="hlt">strain</span> and <span class="hlt">strain</span> rate from cardiac cine-MRI, a modified hierarchical transformation model was proposed. Methods A hierarchical transformation model including the global and local LV deformations was employed to analyze the <span class="hlt">strain</span> and <span class="hlt">strain</span> rate of the left ventricle by cine-MRI image registration. The endocardial and epicardial contour information was introduced to enhance the registration accuracy by combining the original hierarchical algorithm with an Iterative Closest Points using Invariant Features algorithm. The hierarchical model was validated by a normal volunteer first and then applied to two clinical cases (i.e., the normal volunteer and a diabetic patient) to evaluate their respective function. Results Based on the two clinical cases, by comparing the displacement fields of two selected landmarks in the normal volunteer, the proposed method showed a better performance than the original or unmodified model. Meanwhile, the comparison of the radial <span class="hlt">strain</span> between the volunteer and patient demonstrated their apparent functional difference. Conclusions The present method could be used to estimate the LV myocardial <span class="hlt">strain</span> and <span class="hlt">strain</span> rate during a cardiac cycle and thus to quantify the analysis of the LV motion function. PMID:25602778</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19830024945','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19830024945"><span>Effect of <span class="hlt">strain</span> isolator pad modulus on inplane <span class="hlt">strain</span> in Shuttle Orbiter thermal protection system tiles</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Sawyer, J. W.</p> <p>1983-01-01</p> <p>The thermal protection system used on the Space Shuttle orbiter to determine <span class="hlt">strains</span> in the reusable surface insulation tiles under simulated flight loads was investigated. The effects of changes in the <span class="hlt">strain</span> isolator pad (SIP) moduli on the <span class="hlt">strains</span> in the tile were evaluated. To analyze the SIP/tile system, it was necessary to conduct tests to determine inplane tension and compression modulus and inplane failure <span class="hlt">strain</span> for the densified layer of the tiles. It is shown that densification of the LI-900 tile material increases the modulus by a factor of 6 to 10 and reduces the failure <span class="hlt">strain</span> by about 50%. It is indicated that the inplane <span class="hlt">strain</span> levels in the Shuttle tiles in the highly loaded regions are approximately 2 orders of magnitude lower than the failure <span class="hlt">strain</span> of the material. It is concluded that most of the LI-900 tiles on the Shuttle could be mounted on a SIP with tensile and shear stiffnesses 10 times those of the present SIP without inplane <span class="hlt">strain</span> failure in the tile.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/22840216','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/22840216"><span>Hepatitis E virus <span class="hlt">strains</span> in rabbits and evidence of a closely related <span class="hlt">strain</span> in humans, France.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Izopet, Jacques; Dubois, Martine; Bertagnoli, Stéphane; Lhomme, Sébastien; Marchandeau, Stéphane; Boucher, Samuel; Kamar, Nassim; Abravanel, Florence; Guérin, Jean-Luc</p> <p>2012-08-01</p> <p>Hepatitis E virus (HEV) <span class="hlt">strains</span> from rabbits indicate that these mammals may be a reservoir for HEVs that cause infection in humans. To determine HEV prevalence in rabbits and the <span class="hlt">strains</span>' genetic characteristics, we tested bile, liver, and additional samples from farmed and wild rabbits in France. We detected HEV RNA in 7% (14/200) of bile samples from farmed rabbits (in 2009) and in 23% (47/205) of liver samples from wild rabbits (in 2007-2010). Full-length genomic sequences indicated that all rabbit <span class="hlt">strains</span> belonged to the same clade (nucleotide sequences 72.2%-78.2% identical to HEV genotypes 1-4). Comparison with HEV sequences of human <span class="hlt">strains</span> and reference sequences identified a human <span class="hlt">strain</span> closely related to rabbit <span class="hlt">strain</span> HEV. We found a 93-nt insertion in the X domain of open reading frame 1 of the human <span class="hlt">strain</span> and all rabbit HEV <span class="hlt">strains</span>. These findings indicate that the host range of HEV in Europe is expanding and that zoonotic transmission of HEV from rabbits is possible.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19850007898','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19850007898"><span>Measurement of high temperature <span class="hlt">strain</span> by the laser-speckle <span class="hlt">strain</span> gauge</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Yamaguchi, I.</p> <p>1984-01-01</p> <p>By using the laser-speckle <span class="hlt">strain</span> gauge, the <span class="hlt">strain</span> of metal at the temperature lower than 250 C is measured. The principle of the gauge is to measure the expansion or contraction of the fine structures of surface by detecting the resultant speckle displacement in an optoelectronic way, whereby the effect of rigid-body motion is automatically cancelled out with the aid of a differential detection system. A transportable apparatus was built and a comparison experiment performed with a resistance <span class="hlt">strain</span> gauge at room temperature. It has a <span class="hlt">strain</span> sensitivity of .00002, a gauge length smaller than 1 mm, and no upper limit in a range of <span class="hlt">strain</span> measurement. In the measurement of high-temperature <span class="hlt">strain</span> it is free from the need for a dummy gauge and insensitive to an electric drift effect. As examples of <span class="hlt">strain</span> measurement at high-temperature, thermal expansion and contraction of a top of a soldering iron are measured. The interval of the measurement can be made at shortest 1.6 sec. and the change in the <span class="hlt">strain</span> is clearly followed until the ultimate stationary temperature is reached.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/16178463','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/16178463"><span>[Deoxyribonuclease activity detection in Clostridium chauvoei <span class="hlt">strains</span>].</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Carloni, G H; Bentancor, L D; De Torres, R A</p> <p>2005-01-01</p> <p>Beta toxin of C. chauvoei has desoxiribonuclease (DNase) activity which is regarded as one of its virulence factors. The production of DNase was detected in <span class="hlt">strains</span> isolated from bovines, using as controls C. chauvoei ATCC 10092, and C. perfringens Type A and C. septicum, both laboratory isolates. The enzyme activity was made evident on a DNA substrate observing the macroscopic degradation. A simple methodology was developed using a commercial medium for DNase test, with the incorporation of sterile horse serum. Each <span class="hlt">strain</span> was streaked on the surface of the medium, incubated in anaerobic atmosphere at 37 degrees C for 48 hours. The plates were revealed with HCI 1 N. The appearance of a clear and transparent zone around and under the microbial growing was considered a positive reaction. Enzyme activity was detected in 10 of 12 <span class="hlt">strains</span> and also in the controls. The serum addition to the commercial basal medium allows the optimum development of the microorganism showing the enzymatic digestion zone.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_24 --> <div id="page_25" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li class="active"><span>25</span></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="481"> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/21666210','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/21666210"><span>Genetic characterization of measles vaccine <span class="hlt">strains</span>.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Bankamp, Bettina; Takeda, Makoto; Zhang, Yan; Xu, Wenbo; Rota, Paul A</p> <p>2011-07-01</p> <p>The complete genomic sequences of 9 measles vaccine <span class="hlt">strains</span> were compared with the sequence of the Edmonston wild-type virus. AIK-C, Moraten, Rubeovax, Schwarz, and Zagreb are vaccine <span class="hlt">strains</span> of the Edmonston lineage, whereas CAM-70, Changchun-47, Leningrad-4 and Shanghai-191 were derived from 4 different wild-type isolates. Nucleotide substitutions were found in the noncoding regions of the genomes as well as in all coding regions, leading to deduced amino acid substitutions in all 8 viral proteins. Although the precise mechanisms involved in the attenuation of individual measles vaccines remain to be elucidated, in vitro assays of viral protein functions and recombinant viruses with defined genetic modifications have been used to characterize the differences between vaccine and wild-type <span class="hlt">strains</span>. Although almost every protein contributes to an attenuated phenotype, substitutions affecting host cell tropism, virus assembly, and the ability to inhibit cellular antiviral defense mechanisms play an especially important role in attenuation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015APS..MAR.F4002B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015APS..MAR.F4002B"><span>Diffraction Correlation to Reconstruct Highly <span class="hlt">Strained</span> Particles</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Brown, Douglas; Harder, Ross; Clark, Jesse; Kim, J. W.; Kiefer, Boris; Fullerton, Eric; Shpyrko, Oleg; Fohtung, Edwin</p> <p>2015-03-01</p> <p>Through the use of coherent x-ray diffraction a three-dimensional diffraction pattern of a highly <span class="hlt">strained</span> nano-crystal can be recorded in reciprocal space by a detector. Only the intensities are recorded, resulting in a loss of the complex phase. The recorded diffraction pattern therefore requires computational processing to reconstruct the density and complex distribution of the diffracted nano-crystal. For highly <span class="hlt">strained</span> crystals, standard methods using HIO and ER algorithms are no longer sufficient to reconstruct the diffraction pattern. Our solution is to correlate the symmetry in reciprocal space to generate an a priori shape constraint to guide the computational reconstruction of the diffraction pattern. This approach has improved the ability to accurately reconstruct highly <span class="hlt">strained</span> nano-crystals.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1981RScI...52.1417R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1981RScI...52.1417R"><span>Simple and sensitive <span class="hlt">strain</span> gauge displacement transducer</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ramana, Y. V.; Sarma, L. P.</p> <p>1981-09-01</p> <p>We describe a simple and sensitive <span class="hlt">strain</span> gauge displacement transducer. It is based on the linear movement of a shaft (with two cantilevers and four <span class="hlt">strain</span> gauges) in a tapered chamber, resulting in a change in resistance proportional to the cantilever deformation. The transducer with its Wheatstone full bridge configuration is calibrated against a mechanical dial indicator of 0.002 mm accuracy for both ac and dc voltage excitations. Its output is linear for measurements of full range displacement up to 25 mm. It has a sensitivity of ±0.0082 mm for ac excitation with a <span class="hlt">strain</span> indicator whose resolution is ±1 μɛ. It has a dc full range sensitivity of 1.5 mV/V for excitation levels up to 5 V. It can have varied field and laboratory applications wherever displacements are precisely read, recorded, or monitored.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4286197','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4286197"><span>Genome sequence of Coxiella burnetii <span class="hlt">strain</span> Namibia</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p></p> <p>2014-01-01</p> <p>We present the whole genome sequence and annotation of the Coxiella burnetii <span class="hlt">strain</span> Namibia. This <span class="hlt">strain</span> was isolated from an aborting goat in 1991 in Windhoek, Namibia. The plasmid type QpRS was confirmed in our work. Further genomic typing placed the <span class="hlt">strain</span> into a unique genomic group. The genome sequence is 2,101,438 bp long and contains 1,979 protein-coding and 51 RNA genes, including one rRNA operon. To overcome the poor yield from cell culture systems, an additional DNA enrichment with whole genome amplification (WGA) methods was applied. We describe a bioinformatics pipeline for improved genome assembly including several filters with a special focus on WGA characteristics. PMID:25593636</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/19777804','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/19777804"><span>[Novel methods and strategies for <span class="hlt">strain</span> improvement].</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zhao, Wenting; Zou, Yi; Hu, Changhua</p> <p>2009-06-01</p> <p>Improvement of the productivity of industrial <span class="hlt">strains</span> is an important field in micro-biology, because wild-type <span class="hlt">strains</span> isolated from nature usually produce only a low level of antibiotics. Although random screening and simple rational screening are still effective without using genomic information, they are always time- and labor-consuming. With the broad application of recombinant DNA technology, protoplast fusion and X-omics, novel methods and strategies such as metabolic engineering, genome shuffling, system biology and system biotechnology, ribosome engineering, epigenetic modification are being exploited for the industry microbiology. In this review, we will focus on the progress of these novel methods and strategies for <span class="hlt">strain</span> improvement in recent years.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016SMaS...25j5008X','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016SMaS...25j5008X"><span>High sensitivity knitted fabric <span class="hlt">strain</span> sensors</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Xie, Juan; Long, Hairu; Miao, Menghe</p> <p>2016-10-01</p> <p>Wearable sensors are increasingly used in smart garments for detecting and transferring vital signals and body posture, movement and respiration. Existing fabric <span class="hlt">strain</span> sensors made from metallized yarns have low sensitivity, poor comfort and low durability to washing. Here we report a knitted fabric <span class="hlt">strain</span> sensor made from a cotton/stainless steel (SS) fibre blended yarn which shows much higher sensitivity than sensors knitted from metallized yarns. The fabric feels softer than pure cotton textiles owing to the ultrafine stainless steel fibres and does not lose its electrical property after washing. The reason for the high sensitivity of the cotton/SS knitted fabric sensor was explored by comparing its sensing mechanism with the knitted fabric sensor made from metallized yarns. The results show that the cotton/SS yarn-to-yarn contact resistance is highly sensitive to <span class="hlt">strain</span> applied to hooked yarn loops.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20150000844','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20150000844"><span>Wing Shape Sensing from Measured <span class="hlt">Strain</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Pak, Chan-Gi</p> <p>2015-01-01</p> <p>A new two step theory is investigated for predicting the deflection and slope of an entire structure using <span class="hlt">strain</span> measurements at discrete locations. In the first step, a measured <span class="hlt">strain</span> is fitted using a piecewise least squares curve fitting method together with the cubic spline technique. These fitted <span class="hlt">strains</span> are integrated twice to obtain deflection data along the fibers. In the second step, computed deflection along the fibers are combined with a finite element model of the structure in order to extrapolate the deflection and slope of the entire structure through the use of System Equivalent Reduction and Expansion Process. The theory is first validated on a computational model, a cantilevered rectangular wing. It is then applied to test data from a cantilevered swept wing model.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26424643','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26424643"><span>Epstein-Barr Virus <span class="hlt">Strain</span> Variation.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Farrell, Paul J</p> <p>2015-01-01</p> <p>What is wild-type Epstein-Barr virus and are there genetic differences in EBV <span class="hlt">strains</span> that contribute to some of the EBV-associated diseases? Recent progress in DNA sequencing has resulted in many new Epstein-Barr virus (EBV) genome sequences becoming available. EBV isolates worldwide can be grouped into type 1 and type 2, a classification based on the EBNA2 gene sequence. Type 1 transforms human B cells into lymphoblastoid cell lines much more efficiently than type 2 EBV and molecular mechanisms that may account for this difference in cell transformation are now becoming understood. Study of geographic variation of EBV <span class="hlt">strains</span> independent of the type 1/type 2 classification and systematic investigation of the relationship between viral <span class="hlt">strains</span>, infection and disease are now becoming possible. So we should consider more directly whether viral sequence variation might play a role in the incidence of some EBV-associated diseases.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/11712610','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/11712610"><span>Conservative treatment for repetitive <span class="hlt">strain</span> injury.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Konijnenberg, H S; de Wilde, N S; Gerritsen, A A; van Tulder, M W; de Vet, H C</p> <p>2001-10-01</p> <p>Various conservative treatment options for repetitive <span class="hlt">strain</span> injury are widely used, despite questionable evidence of their effectiveness. This systematic review evaluates the effectiveness of these treatment options for relieving symptoms of repetitive <span class="hlt">strain</span> injury and improving activities of daily living. Searches in Medline and Embase, with additional reference checking resulted in 15 eligible trials for this review. Methodological quality was assessed, and data-extraction was performed. With the use of a "best-evidence synthesis", no strong evidence was found for the effectiveness of any of the treatment options. There is limited evidence that multidisciplinary rehabilitation, ergonomic intervention measures, exercises, and spinal manipulation combined with soft tissue therapy are effective in providing symptom relief or improving activities of daily living. There is conflicting evidence for the effectiveness of behavioral therapy. In conclusion, little is known about the effectiveness of conservative treatment options for repetitive <span class="hlt">strain</span> injury. To establish strong evidence, more high-quality trials are needed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/956356','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/956356"><span>The breaking <span class="hlt">strain</span> of neutron star crust</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Kadau, Kai; Horowitz, C J</p> <p>2009-01-01</p> <p>Mountains on rapidly rotating neutron stars efficiently radiate gravitational waves. The maximum possible size of these mountains depends on the breaking <span class="hlt">strain</span> of neutron star crust. With multimillion ion molecular dynamics simulations of Coulomb solids representing the crust, we show that the breaking <span class="hlt">strain</span> of pure single crystals is very large and that impurities, defects, and grain boundaries only modestly reduce the breaking <span class="hlt">strain</span> to around 0.1. Due to the collective behavior of the ions during failure found in our simulations, the neutron star crust is likely very strong and can support mountains large enough so that their gTavitational wave radiation could limit the spin periods of some stars and might be detectable in large scale interferometers. Furthermore, our microscopic modeling of neutron star crust material can help analyze mechanisms relevant in Magnetar Giant and Micro Flares.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3586687','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=3586687"><span>Convergent Replication of Mouse Synthetic Prion <span class="hlt">Strains</span></span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Ghaemmaghami, Sina; Colby, David W.; Nguyen, Hoang-Oanh B.; Hayashi, Shigenari; Oehler, Abby; DeArmond, Stephen J.; Prusiner, Stanley B.</p> <p>2014-01-01</p> <p>Prion diseases are neurodegenerative disorders characterized by the aberrant folding of endogenous proteins into self-propagating pathogenic conformers. Prion disease can be initiated in animal models by inoculation with amyloid fibrils formed from bacterially derived recombinant prion protein. The synthetic prions that accumulated in infected organisms are structurally distinct from the amyloid preparations used to initiate their formation and change conformationally on repeated passage. To investigate the nature of synthetic prion transformation, we infected mice with a conformationally diverse set of amyloids and serially passaged the resulting prion <span class="hlt">strains</span>. At each passage, we monitored changes in the biochemical and biological properties of the adapting <span class="hlt">strain</span>. The physicochemical properties of each synthetic prion <span class="hlt">strain</span> gradually changed on serial propagation until attaining a common adapted state with shared physicochemical characteristics. These results indicate that synthetic prions can assume multiple intermediate conformations before converging into one conformation optimized for in vivo propagation. PMID:23438476</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.osti.gov/scitech/biblio/6217136','SCIGOV-STC'); return false;" href="https://www.osti.gov/scitech/biblio/6217136"><span>Glycerol production of various <span class="hlt">strains</span> of saccharomyces</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Radler, F.; Schuetz, H.</p> <p>1982-01-01</p> <p>The quantity of glycerol as principal by-product of the alcoholic fermentation depends to a large extent on the yeast <span class="hlt">strain</span>. Different <span class="hlt">strains</span> of Saccharomyces cerevisiae were found to form amounts of glycerol varying between 4.2 to 10.4 g/L. The formation of glycerol is regarded as a result of the competition between alcohol dehydrogenase and glycerol-3-phosphate dehydrogenase that compete for the reduced coenzyme NADH/sub 2/. High and low glycerol forming yeast <span class="hlt">strains</span> showed large differences in the activity of glycerol-3-phosphate dehydrogenase and only small variation in the activity of alcohol dehydrogenase. The total amount of glycerol formed was also influenced by amino acids. In thiamine deficient media a decrease in glycerol formation was observed. Experiments indicate a correlation between the formation of acetaldehyde and glycerol and the production of cell mass that may be of practical interest. (Refs. 12).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19950022297','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19950022297"><span>Test load verification through <span class="hlt">strain</span> data analysis</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Verderaime, V.; Harrington, F.</p> <p>1995-01-01</p> <p>A traditional binding acceptance criterion on polycrystalline structures is the experimental verification of the ultimate factor of safety. At fracture, the induced <span class="hlt">strain</span> is inelastic and about an order-of-magnitude greater than designed for maximum expected operational limit. At this extreme <span class="hlt">strained</span> condition, the structure may rotate and displace at the applied verification load such as to unknowingly distort the load transfer into the static test article. Test may result in erroneously accepting a submarginal design or rejecting a reliable one. A technique was developed to identify, monitor, and assess the load transmission error through two back-to-back surface-measured <span class="hlt">strain</span> data. The technique is programmed for expediency and convenience. Though the method was developed to support affordable aerostructures, the method is also applicable for most high-performance air and surface transportation structural systems.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/28068587','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/28068587"><span>Quantitative assessment of viable cells of Lactobacillus plantarum <span class="hlt">strains</span> in single, dual and multi-<span class="hlt">strain</span> biofilms.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Fernández Ramírez, Mónica D; Kostopoulos, Ioannis; Smid, Eddy J; Nierop Groot, Masja N; Abee, Tjakko</p> <p>2017-03-06</p> <p>Biofilms of Lactobacillus plantarum are a potential source for contamination and recontamination of food products. Although biofilms have been mostly studied using single species or even single <span class="hlt">strains</span>, it is conceivable that in a range of environmental settings including food processing areas, biofilms are composed of multiple species with each species represented by multiple <span class="hlt">strains</span>. In this study six spoilage related L. plantarum <span class="hlt">strains</span> FBR1-FBR6 and the model <span class="hlt">strain</span> L. plantarum WCFS1 were characterised in single, dual and multiple <span class="hlt">strain</span> competition models. A quantitative PCR approach was used with added propidium monoazide (PMA) enabling quantification of intact cells in the biofilm, representing the viable cell fraction that determines the food spoilage risk. Our results show that the performance of individual <span class="hlt">strains</span> in multi-<span class="hlt">strain</span> cultures generally correlates with their performance in pure culture, and relative <span class="hlt">strain</span> abundance in multi-<span class="hlt">strain</span> biofilms positively correlated with the relative <span class="hlt">strain</span> abundance in suspended (planktonic) cultures. Performance of individual <span class="hlt">strains</span> in dual-<span class="hlt">strain</span> biofilms was highly influenced by the presence of the secondary <span class="hlt">strain</span>, and in most cases no correlation between the relative contributions of viable planktonic cells and viable cells in the biofilm was noted. The total biofilm quantified by CV staining of the dual and multi-<span class="hlt">strain</span> biofilms formed was mainly correlated to CV values of the dominant <span class="hlt">strain</span> obtained in single <span class="hlt">strain</span> studies. However, the combination of <span class="hlt">strain</span> FBR5 and <span class="hlt">strain</span> WCFS1 showed significantly higher CV values compared to the individual performances of both <span class="hlt">strains</span> indicating that total biofilm formation was higher in this specific condition. Notably, L. plantarum FBR5 was able to outgrow all other <span class="hlt">strains</span> and showed the highest relative abundance in dual and multi-<span class="hlt">strain</span> biofilms. All the dual and multi-<span class="hlt">strain</span> biofilms contained a considerable number of viable cells, representing a potential</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19880012129','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19880012129"><span>Controlled-<span class="hlt">strain</span> rate tests at very low <span class="hlt">strain</span> rates of 2618 aluminum at 200 C</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Ding, J. L.; Lee, S. R.</p> <p>1988-01-01</p> <p>Constant <span class="hlt">strain</span> rate tests and constant load creep tests were performed on 2618 aluminum at 200 C. The <span class="hlt">strain</span> rates used in the constant <span class="hlt">strain</span> rate tests were 10 to the minus 6, 10 to the minus 7, 10 to the minum 8, and 10 to the minus 9/sec. Due to the fact that the <span class="hlt">strain</span> rates in both tests were comparable to each other, the similarities between them can therefore be studied. It was concluded that metals are essentially rate sensitive at elevated temperatures. The traditional definition of creep and plasticity used in the classical creep analysis is actually a reflection of the material behavior under different loading conditions. A constitutive equation based on the test data under one loading condition should work well for other loading conditions as long as the <span class="hlt">strain</span> rates are in the same range as those under which the material constants are determined.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ChPhB..24c6801S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ChPhB..24c6801S"><span><span class="hlt">Strain</span> analysis of free-standing <span class="hlt">strained</span> silicon-on-insulator nanomembrane</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sun, Gao-Di; Dong, Lin-Xi; Xue, Zhong-Ying; Chen, Da; Guo, Qing-Lei; Mu, Zhi-Qiang</p> <p>2015-03-01</p> <p>Based on the ultra-thin <span class="hlt">strained</span> silicon-on-insulator (sSOI) technology, by creatively using a hydrofluoric acid (HF) vapor corrosion system to dry etch the SiO2 layer, a large area of suspended <span class="hlt">strained</span> silicon (sSi) nanomembrane with uniform <span class="hlt">strain</span> distribution is fabricated. The <span class="hlt">strain</span> state in the implemented nanomembrane is comprehensively analyzed by using an UV-Raman spectrometer with different laser powers. The results show that the inherent <span class="hlt">strain</span> is preserved while there are artificial Raman shifts induced by the heat effect, which is proportional to the laser power. The suspended sSOI nanomembrane will be an important material for future novel high-performance devices. Project supported by the National Natural Science Foundation of China (Grant Nos. 61376117 and 61107025) and the Zhejiang Provincial Natural Science Foundation of China (Grant No. LY13F040004).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4982289','PMC'); return false;" href="https://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4982289"><span>Complete Genome Sequence of the Oncolytic Sendai virus <span class="hlt">Strain</span> Moscow</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Zainutdinov, Sergei S.; Tikunov, Artem Y.; Matveeva, Olga V.</p> <p>2016-01-01</p> <p>We report here the complete genome sequence of Sendai virus Moscow <span class="hlt">strain</span>. Anecdotal evidence for the efficacy of oncolytic virotherapy exists for this <span class="hlt">strain</span>. The RNA genome of the Moscow <span class="hlt">strain</span> is 15,384 nucleotides in length and differs from the nearest <span class="hlt">strain</span>, BB1, by 18 nucleotides and 11 amino acids. PMID:27516510</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=19740031112&hterms=magnesium+oxide&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dmagnesium%2Boxide','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=19740031112&hterms=magnesium+oxide&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dmagnesium%2Boxide"><span>Dynamic <span class="hlt">strain</span> aging in magnesium oxide single crystals</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Srinivasan, M.; Stoebe, T. G.</p> <p>1973-01-01</p> <p><span class="hlt">Strain</span> rate change transients are considered together with aspects of serrated flow, questions of flow stress and work hardening during dynamic <span class="hlt">strain</span> aging, and time, temperature, and prestrain dependence of <span class="hlt">strain</span> aging. On continuing the deformation process after aging for certain periods of time for a particular <span class="hlt">strain</span>, a subsidiary load drop is sometimes observed in addition to the main yield drops.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.ncbi.nlm.nih.gov/pubmed/26769927','PUBMED'); return false;" href="https://www.ncbi.nlm.nih.gov/pubmed/26769927"><span>Draft Genome Sequences of Achromobacter piechaudii GCS2, Agrobacterium sp. <span class="hlt">Strain</span> SUL3, Microbacterium sp. <span class="hlt">Strain</span> GCS4, Shinella sp. <span class="hlt">Strain</span> GWS1, and Shinella sp. <span class="hlt">Strain</span> SUS2 Isolated from Consortium with the Hydrocarbon-Producing Alga Botryococcus braunii.</span></a></p> <p><a target="_blank" href="https://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Jones, Katy J; Moore, Karen; Sambles, Christine; Love, John; Studholme, David J; Aves, Stephen J</p> <p>2016-01-14</p> <p>A variety of bacteria associate with the hydrocarbon-producing microalga Botryococcus braunii, some of which may influence its growth. We report here the genome sequences for Achromobacter piechaudii GCS2, Agrobacterium sp. <span class="hlt">strain</span> SUL3, Microbacterium sp. <span class="hlt">strain</span> GCS4, and Shinella sp. <span class="hlt">strains</span> GWS1 and SUS2, isolated from a laboratory culture of B. braunii, race B, <span class="hlt">strain</span> Guadeloupe.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://ntrs.nasa.gov/search.jsp?R=20000024984&hterms=new+madrid+seismic+zone&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dnew%2Bmadrid%2Bseismic%2Bzone','NASA-TRS'); return false;" href="https://ntrs.nasa.gov/search.jsp?R=20000024984&hterms=new+madrid+seismic+zone&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dnew%2Bmadrid%2Bseismic%2Bzone"><span>Stresses and <span class="hlt">Strains</span> within the "Stable" North American Plate</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Engeln, Joe</p> <p>1995-01-01</p> <p>This paper presents a final report on "Stresses and <span class="hlt">Strains</span> within the "Stable" North American Plate". The topics include: 1) <span class="hlt">Strain</span> rates near the New Madrid seismic zone; 2) Signal Processing of intermediate term data; and 3) Transform fault stresses and <span class="hlt">strains</span>. The paper also includes graphs of the stress and <span class="hlt">strain</span> distributions.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li class="active"><span>25</span></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_25 --> <center> <div class="footer-extlink text-muted"><small>Some links on this page may take you to non-federal websites. 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