Sample records for conditional lethal mutants

  1. A Nutritional Conditional Lethal Mutant Due to Pyridoxine 5?-Phosphate Oxidase Deficiency in Drosophila melanogaster

    PubMed Central

    Chi, Wanhao; Zhang, Li; Du, Wei; Zhuang, Xiaoxi

    2014-01-01

    The concept of auxotrophic complementation has been proposed as an approach to identify genes in essential metabolic pathways in Drosophila melanogaster. However, it has achieved limited success to date, possibly due to the low probability of finding mutations fit with the chemically defined profile. Instead of using the chemically defined culture media lacking specific nutrients, we used bare minimum culture medium, i.e., 4% sucrose, for adult Drosophila. We identified a nutritional conditional lethal mutant and localized a c.95C > A mutation in the Drosophila pyridoxine 5?-phosphate oxidase gene [dPNPO or sugarlethal (sgll)] using meiotic recombination mapping, deficiency mapping, and whole genome sequencing. PNPO converts dietary vitamin B6 such as pyridoxine to its active form pyridoxal 5?-phosphate (PLP). The missense mutation (sgll95) results in the substitution of alanine to aspartate (p.Ala32Asp). The sgll95 flies survive well on complete medium but all die within 6 d on 4% sucrose only diet, which can be rescued by pyridoxine or PLP supplement, suggesting that the mutation does not cause the complete loss of PNPO activity. The sgll knockdown further confirms its function as the Drosophila PNPO. Because better tools for positional cloning and cheaper whole genome sequencing have made the identification of point mutations much easier than before, alleviating the necessity to pinpoint specific metabolic pathways before gene identification, we propose that nutritional conditional screens based on bare minimum growth media like ours represent promising approaches for discovering important genes and mutations in metabolic pathways, thereby accelerating the establishment of in vivo models that recapitulate human metabolic diseases. PMID:24739647

  2. Characterization of Helicobacter pylori dapE and construction of a conditionally lethal dapE mutant.

    PubMed Central

    Karita, M; Etterbeek, M L; Forsyth, M H; Tummuru, M K; Blaser, M J

    1997-01-01

    Helicobacter pylori colonizes the human gastric mucosa and causes gastritis, ulceration, or gastric cancer. A previously uncharacterized region of the H. pylori genome was identified and sequenced. This region includes a putative operon containing three open reading frames termed gidA (1,866 bp), dapE (1,167 bp), and orf2 (753 bp); the gidA and dapE products are highly homologous to other bacterial proteins. In E. coli, dapE encodes N-succinyl-L-diaminopimelic acid desuccinylase, which catalyzes the hydrolysis of N-succinyl-L-diaminopimelic acid to L-diaminopimelic acid (L-DAP) and succinate. When wild-type H. pylori strains were transformed to select for dapE mutagenesis, mutants were present when plates were supplemented with DAP but not with lysine; orf2 mutants were selected without DAP supplementation. Consistent with the finding that GidA is essential in Escherichia coli, we were unable to obtain a gidA mutant in H. pylori despite evidence that insertional mutagenesis had occurred. The positions of gidA, dapE, and orf2 suggest that they form an operon, which was supported by slot blot RNA hybridization and reverse transcriptase PCR studies. The data imply that the H. pylori dapE mutant may be useful as a conditionally lethal vaccine. PMID:9317022

  3. [Synthetic lethal genes to mutant p53].

    PubMed

    Tongyang, Liu; Haiqiang, Guo; Meiyan, Zhu; Yingze, Huang; Shuting, Jia; Ying, Luo; Jihong, Zhang

    2015-04-01

    Targeted therapy has become a powerful approach for cancer treatment. Better understanding of oncogenes as well as synthetic lethal interactions with oncogenes will lead to new strategies for tumor-specific treatment. It is well known that mutant p53 plays an important role in tumorigenesis and tumor development. Thus, understanding the synthetic lethal relationship between p53 mutations and interacting genes in tumor is critical for the personalized treatments of p53 mutant tumors. Synthetic lethal genes to mutant p53 can be divided into cell cycle regulators and non-cell cycle regulators. This paper review show these two types of target genes contribute to synthetic lethal interactions with p53 mutations and potential applications of these interactions in anticancer therapy. PMID:25881697

  4. Identification and sequence analysis of the gene mutated in the conditionally lethal outer membrane permeability mutant SS-C of Salmonella typhimurium.

    PubMed Central

    Hirvas, L; Koski, P; Vaara, M

    1991-01-01

    The biosynthesis and structure-function relationships of the enterobacterial outer membrane are subjects of current intensive research. We have previously described the antibiotic supersensitive SS-C mutant (SH7622) of Salmonella typhimurium and shown that its outer membrane permeability barrier against hydrophobic antibiotics is severely defective. In this study, we show that this mutant is heat-sensitive, conditionally lethal, and carries a missense base-pair substitution in a novel gene which we have recently reported and now named the ssc gene. ssc encodes an earlier uncharacterized 36 kd protein (the Ssc protein) and the mutant expresses Ssc which has valine 291 changed to methionine in a methionine-rich region of Ssc. A plasmid containing the wild-type ssc allele completely reverts the antibiotic- and heat-sensitive phenotype of the SS-C mutant. Corresponding plasmids carrying the mutant allele, or an identical mutant allele prepared by localized mutagenesis, are inactive. The ssc gene is probably analogous to the firA locus of Escherichia coli which has earlier been implicated in a totally different function, mRNA synthesis. Furthermore, ssc apparently lies very close to the lpx genes involved in the thus far known steps of lipid A biosynthesis (the distance, approximately 560 bp). To conclude, our findings define a new essential gene involved in the generation of the outer membrane. Images PMID:2009853

  5. Genetic Analysis of a Temperature-Resistant Revertant of the Conditional Lethal Escherichia coli Double Mutant polA12 uvrE502

    PubMed Central

    Smirnov, G. B.; Saenko, A. S.

    1974-01-01

    Conditional lethality of the Escherichia coli polA12 uvrE502 double mutant may be overcome by a mutation that has been termed polA350. The polA350 mutation restored the polymerizing activity of deoxyribonucleic acid polymerase I at 42 C in the polA12 mutant and partially suppressed ultraviolet (UV) and methylmethane sulfonate sensitivities of the polA12. Mapping experiments have located polA350 between metE and polA12, very close to the latter. The strain carrying polA12 polA350 and recB21 was viable at 42 C. The effects of the recB21 and polA12 polA350 combination on the UV sensitivity were additive. The triple mutant polA12 polA350 uvrE502 was more UV sensitive than the single uvrE502 mutant. PMID:4366022

  6. Lethal infection by Bordetella pertussis mutants in the infant mouse model.

    PubMed Central

    Weiss, A A; Goodwin, M S

    1989-01-01

    Different aspects of lethal infection of infant mice with Bordetella pertussis were examined. Mutants deficient in vir-regulated genes were tested for the ability to cause a lethal infection in the infant mouse model. Adenylate cyclase toxin-hemolysin and pertussis toxin were required to cause a lethal infection at low doses. Mixed infection caused by challenging the mice with an equal number of pertussis toxin and adenylate cyclase toxin-hemolysin mutants at a dose at which neither alone was lethal was also unable to cause a lethal infection. Production of the filamentous hemagglutinin and the dermonecrotic toxin was not required to cause a lethal infection. Nine other mutants in vir-regulated genes whose phenotypes have yet to be determined were also tested. Only two of these mutants were impaired in the ability to cause a lethal infection. Expression of fimbriae does not appear to affect the dose required to cause a lethal infection; however, fimbrial expression was correlated with the later stages of a nonlethal, persistent infection. Growth of the bacteria in MgSO4, a condition which reversibly suppresses expression of the genes required for virulence, did not alter the ability of the bacteria to cause a lethal infection. Auxotrophic mutants deficient in leucine biosynthesis were as virulent as the parental strain; however, mutants deficient in methionine biosynthesis were less virulent. A B. parapertussis strain was much less effective in promoting a lethal infection than any of the wild-type B. pertussis strains examined. A persistent infection in the lungs was observed for weeks after challenge for mice given a sublethal dose of B. pertussis, and transmission from infected infants to the mother was never observed. PMID:2572561

  7. Temperature-Sensitive Cell-Lethal Mutants of Drosophila: Isolation and Characterization

    PubMed Central

    Arking, Robert

    1975-01-01

    One hundred and twenty-one temperature-sensitive (ts) sex-linked lethals were screened by means of X-ray-induced somatic crossing over to determine if any were ts cell-lethal mutants. Cell-lethal mutations were identified by their ability to block the development of homozygous clones when raised under restrictive conditions (29°). Twenty-two ts cell-lethal mutants were isolated and categorized into three classes, depending upon the patterns of damage observed in larval and imaginal tissues. The phenotypes produced by these mutations ranged from those which affected only a limited set of structures (i.e., genital discs only) to those which affected diverse tissues at all stages of the life cycle. Each mutation has its own characteristic time-dependent pattern, frequency, and type of damage. All the mutations affect imaginal tissue, but only one-third of the mutations affect both larval and imaginal tissue. The fastest-acting lethals need 15 hours at the restrictive temperature to kill the cells and the slowest-acting lethals require at least 48 hours. By choosing the appropriate mutant and by manipulating the times of exposure to the restrictive temperature, it has proven possible to produce duplications and deficiencies in specific structures of the adult. A mechanism by which lethality might yield such structures is suggested. In addition, 15 of the mutants are ts female sterile mutants. Only one of these 15 mutants can recover its fertility when shifted back down to the permissive temperature (22°). PMID:821813

  8. Medical Conditions and Nearly Lethal Suicide Attempts.

    ERIC Educational Resources Information Center

    Ikeda, Robin M.; Kresnow, Marcie-jo; Mercy, James A.; Powell, Kenneth E.; Simon, Thomas R.; Potter, Lloyd B.; Durant, Tonji M.; Swahn, Monica H.

    2002-01-01

    This population-based, case-control study examined physical illness as a risk factor for suicidal behavior. Case patients were more likely than controls to report having any serious medical conditions. Results suggest that young men with medical conditions are at increased risk for nearly lethal suicide attempts. (Contains 33 references and 3…

  9. Structure-Based Systematic Isolation of Conditional-Lethal Mutations in the Single Yeast Calmodulin Gene

    PubMed Central

    Ohya, Y.; Botstein, D.

    1994-01-01

    Conditional-lethal mutations of the single calmodulin gene in Saccharomyces cerevisiae have been very difficult to isolate by random and systematic methods, despite the fact that deletions cause recessive lethality. We report here the isolation of numerous conditional-lethal mutants that were recovered by systematically altering phenylalanine residues. The phenylalanine residues of calmodulin were implicated in function both by structural studies of calmodulin bound to target peptides and by their extraordinary conservation in evolution. Seven single and 26 multiple Phe -> Ala mutations were constructed. Mutant phenotypes were examined in a haploid cmd1 disrupted strain under three conditions: single copy, low copy, and overexpressed. Whereas all but one of the single mutations caused no obvious phenotype, most of the multiple mutations caused obvious growth phenotypes. Five were lethal, 6 were lethal only in synthetic medium, 13 were temperature-sensitive lethal and 2 had no discernible phenotypic consequences. Overexpression of some of the mutant genes restored the phenotype to nearly wild type. Several temperature-sensitive calmodulin mutations were suppressed by elevated concentration of CaCl(2) in the medium. Mutant calmodulin protein was detected at normal levels in extracts of most of the lethal mutant cells, suggesting that the deleterious phenotypes were due to loss of the calmodulin function and not protein instability. Analysis of diploid strains heterozygous for all combinations of cmd1-ts alleles revealed four intragenic complementation groups. The contributions of individual phe->ala changes to mutant phenotypes support the idea of internal functional redundancy in the symmetrical calmodulin protein molecule. These results suggest that the several phenylalanine residues in calmodulin are required to different extents in different combinations in order to carry out each of the several essential tasks. PMID:7896089

  10. Strategies for Molecularly Enhanced Chemotherapy to Achieve Synthetic Lethality in Endometrial Tumors with Mutant p53

    PubMed Central

    Meng, Xiangbing; Dizon, Don S.; Yang, Shujie; Wang, Xinjun; Zhu, Danlin; Thiel, Kristina W.; Leslie, Kimberly K.

    2013-01-01

    Serous uterine endometrial carcinomas are aggressive type II cancers with poor outcomes for which new treatment strategies are urgently needed, in particular, strategies that augment sensitivity to established chemotherapy regimens. The tumor suppressor gene TP53 is dysregulated in more than 90% of serous tumors, altering master regulators of the G2/M cell cycle checkpoint in unique and predictable ways and desensitizing cells to chemotherapy. We hypothesized that synthetic lethality can be achieved in endometrial cancer cells with mutant p53 by combining paclitaxel with agents to overcome G2/M arrest and induce mitotic catastrophe. The combination of BIBF1120, an investigational VEGFR, PDGFR, and FGFR multityrosine kinase inhibitor with established anti-angiogenic activity, with paclitaxel abrogated the G2/M checkpoint in p53-null endometrial cancer cells via modulation of G2/M checkpoint regulators followed by induction of mitotic cell death. In endometrial cancer cells harboring an oncogenic gain-of-function p53 mutation, synthetic lethality was created by combining paclitaxel with BIBF1120 and a histone deacetylase inhibitor, which serves to destabilize mutant p53. These cells were also sensitive to an inhibitor of the G2/M kinase Wee1 in combination with paclitaxel. These findings reveal that, in addition to antiangiogenic activity, the angiokinase inhibitor BIBF1120 can be used to restore sensitivity to paclitaxel and induce mitotic cell death in endometrial cancer cells with non-functional p53. These preclinical data serve as a critical platform for the creative design of future clinical trials utilizing molecularly enhanced chemotherapy to achieve synthetic lethality based on the mutational landscape. PMID:24381593

  11. Lethal Mutants and Truncated Selection Together Solve a Paradox of the Origin of Life

    PubMed Central

    Saakian, David B.; Biebricher, Christof K.; Hu, Chin-Kun

    2011-01-01

    Background Many attempts have been made to describe the origin of life, one of which is Eigen's cycle of autocatalytic reactions [Eigen M (1971) Naturwissenschaften 58, 465–523], in which primordial life molecules are replicated with limited accuracy through autocatalytic reactions. For successful evolution, the information carrier (either RNA or DNA or their precursor) must be transmitted to the next generation with a minimal number of misprints. In Eigen's theory, the maximum chain length that could be maintained is restricted to nucleotides, while for the most primitive genome the length is around . This is the famous error catastrophe paradox. How to solve this puzzle is an interesting and important problem in the theory of the origin of life. Methodology/Principal Findings We use methods of statistical physics to solve this paradox by carefully analyzing the implications of neutral and lethal mutants, and truncated selection (i.e., when fitness is zero after a certain Hamming distance from the master sequence) for the critical chain length. While neutral mutants play an important role in evolution, they do not provide a solution to the paradox. We have found that lethal mutants and truncated selection together can solve the error catastrophe paradox. There is a principal difference between prebiotic molecule self-replication and proto-cell self-replication stages in the origin of life. Conclusions/Significance We have applied methods of statistical physics to make an important breakthrough in the molecular theory of the origin of life. Our results will inspire further studies on the molecular theory of the origin of life and biological evolution. PMID:21814563

  12. Dysfunctional conformational dynamics of protein kinase A induced by a lethal mutant of phospholamban hinder phosphorylation.

    PubMed

    Kim, Jonggul; Masterson, Larry R; Cembran, Alessandro; Verardi, Raffaello; Shi, Lei; Gao, Jiali; Taylor, Susan S; Veglia, Gianluigi

    2015-03-24

    The dynamic interplay between kinases and substrates is crucial for the formation of catalytically committed complexes that enable phosphoryl transfer. However, a clear understanding on how substrates modulate kinase structural dynamics to control catalytic efficiency is still missing. Here, we used solution NMR spectroscopy to study the conformational dynamics of two complexes of the catalytic subunit of the cAMP-dependent protein kinase A with WT and R14 deletion phospholamban, a lethal human mutant linked to familial dilated cardiomyopathy. Phospholamban is a central regulator of heart muscle contractility, and its phosphorylation by protein kinase A constitutes a primary response to ?-adrenergic stimulation. We found that the single deletion of arginine in phospholamban's recognition sequence for the kinase reduces its binding affinity and dramatically reduces phosphorylation kinetics. Structurally, the mutant prevents the enzyme from adopting conformations and motions committed for catalysis, with concomitant reduction in catalytic efficiency. Overall, these results underscore the importance of a well-tuned structural and dynamic interplay between the kinase and its substrates to achieve physiological phosphorylation levels for proper Ca(2+) signaling and normal cardiac function. PMID:25775607

  13. Construction of conditional knockdown mutants in mycobacteria.

    PubMed

    Schnappinger, Dirk; O'Brien, Kathryn M; Ehrt, Sabine

    2015-01-01

    By definition, essential genes are fundamental to bacterial growth, yet the functions of many such genes remain unknown. Essential genes furthermore are central to the activity of most antibacterial drugs and among the most attractive targets for the development of new therapeutics. This chapter describes how synthetic genetic switches that utilize transcriptional repression, controlled proteolysis, or both to silence gene activity can be applied to construct and characterize conditional knockdown (cKD) mutants for essential genes in Mycobacterium smegmatis and Mycobacterium tuberculosis. PMID:25779315

  14. Lethal mitochondrial cardiomyopathy in a hypomorphic Med30 mouse mutant is ameliorated by ketogenic diet

    PubMed Central

    Krebs, Philippe; Fan, Weiwei; Chen, Yen-Hui; Tobita, Kimimasa; Downes, Michael R.; Wood, Malcolm R.; Sun, Lei; Xia, Yu; Ding, Ning; Spaeth, Jason M.; Moresco, Eva Marie Y.; Boyer, Thomas G.; Lo, Cecilia Wen Ya; Yen, Jeffrey; Evans, Ronald M.; Beutler, Bruce

    2011-01-01

    Deficiencies of subunits of the transcriptional regulatory complex Mediator generally result in embryonic lethality, precluding study of its physiological function. Here we describe a missense mutation in Med30 causing progressive cardiomyopathy in homozygous mice that, although viable during lactation, show precipitous lethality 2–3 wk after weaning. Expression profiling reveals pleiotropic changes in transcription of cardiac genes required for oxidative phosphorylation and mitochondrial integrity. Weaning mice to a ketogenic diet extends viability to 8.5 wk. Thus, we establish a mechanistic connection between Mediator and induction of a metabolic program for oxidative phosphorylation and fatty acid oxidation, in which lethal cardiomyopathy is mitigated by dietary intervention. PMID:22106289

  15. Haploinsufficient lethality and formation of arteriovenous malformations in Notch pathway mutants

    Microsoft Academic Search

    L. T. Krebs; J R Shutter; K Tanigaki; T Honjo; K L Stark; T Gridley

    2004-01-01

    The Notch signaling pathway is essential for embryonic vascular development in vertebrates. Here we show that mouse embryos heterozygous for a targeted mutation in the gene encoding the DLL4 ligand exhibit haploinsufficient lethality because of defects in vascular remodeling. We also describe vascular defects in embryos homozygous for a mutation in the Rbpsuh gene, which encodes the primary transcriptional mediator

  16. Potentially lethal damage repair is due to the difference of DNA double-strand break repair under immediate and delayed plating conditions

    SciTech Connect

    Frankenberg-Schwager, M.; Frankenberg, D.; Harbich, R.

    1987-08-01

    Cells plated immediately after irradiation on nutrient agar (immediate plating) exhibit a lower survival than cells which are kept under nongrowth conditions before plating (delayed plating). The difference between the survival curves obtained after immediate plating and delayed plating is considered to exhibit the cell's capacity to repair potentially lethal damage. In yeast evidence has been presented previously for the DNA double-strand break (DSB) as the molecular lesion involved in the repair of potentially lethal damage observed at the cellular level. Radiation-induced DSB are repaired in cells plated on nutrient agar, i.e., under growth conditions, as well as in cells kept under nongrowth conditions. In this paper DSB repair under growth and nongrowth conditions is studied with the help of the yeast mutant rad54-3 which is temperature conditional for DSB repair. It is shown that the extent of repair of potentially lethal damage can be varied by shifting the relative fractions of repair of DSB under growth conditions versus nongrowth conditions. Repair of DSB in cells plated on nutrient agar is promoted when glucose is substituted by Na-succinate as an energy source. As a result the immediate plating survival curve approaches the delayed plating survival curve, thus reducing the operationally defined repair of potentially lethal damage. We show that this reduced potentially lethal damage repair is caused, however, by a higher amount of DSB repair in cells immediately plated on succinate agar as compared to glucose agar.

  17. Characterization of Synthetic-Lethal Mutants Reveals a Role for the Saccharomyces Cerevisiae Guanine-Nucleotide Exchange Factor Cdc24p in Vacuole Function and Na(+) Tolerance

    PubMed Central

    White, W. H.; Johnson, D. I.

    1997-01-01

    Cdc24p is the guanine-nucleotide exchange factor for the Cdc42p GTPase, which controls cell polarity in Saccharomyces cerevisiae. To identify new genes that may affect cell polarity, we characterized six UV-induced csl (CDC24 synthetic-lethal) mutants that exhibited synthetic-lethality with cdc24-4(ts) at 23°. Five mutants were not complemented by plasmid-borne CDC42, RSR1, BUD5, BEM1, BEM2, BEM3 or CLA4 genes, which are known to play a role in cell polarity. The csl3 mutant displayed phenotypes similar to those observed with calcium-sensitive, Pet(-) vma mutants defective in vacuole function. CSL5 was allelic to VMA5, the vacuolar H(+)-ATPase subunit C, and one third of csl5 cdc24-4(ts) cells were elongated or had misshapen buds. A cdc24-4(ts) ?vma5::LEU2 double mutant did not exhibit synthetic lethality, suggesting that the csl5/vma5 cdc24-4(ts) synthetic-lethality was not simply due to altered vacuole function. The cdc24-4(ts) mutant, like ?vma5::LEU2 and csl3 mutants, was sensitive to high levels of Ca(2+) as well as Na(+) in the growth media, which did not appear to be a result of a fragile cell wall because the phenotypes were not remedied by 1 M sorbitol. Our results indicated that Cdc24p was required in one V-ATPase mutant and another mutant affecting vacuole morphology, and also implicated Cdc24p in Na(+) tolerance. PMID:9286667

  18. Synthetic lethality in ATM-deficient RAD50-mutant tumors underlie outlier response to cancer therapy

    PubMed Central

    Al-Ahmadie, Hikmat; Iyer, Gopa; Hohl, Marcel; Asthana, Saurabh; Inagaki, Akiko; Schultz, Nikolaus; Hanrahan, Aphrothiti J.; Scott, Sasinya N.; Brannon, A. Rose; McDermott, Gregory C.; Pirun, Mono; Ostrovnaya, Irina; Kim, Philip; Socci, Nicholas D.; Viale, Agnes; Schwartz, Gary K.; Reuter, Victor; Bochner, Bernard H.; Rosenberg, Jonathan E.; Bajorin, Dean F.; Berger, Michael F.; Petrini, John H.J.; Solit, David B.; Taylor, Barry S.

    2014-01-01

    Metastatic solid tumors are almost invariably fatal. Patients with disseminated small-cell cancers have a particularly unfavorable prognosis with most succumbing to their disease within two years. Here, we report on the genetic and functional analysis of an outlier curative response of a patient with metastatic small cell cancer to combined checkpoint kinase 1 (Chk1) inhibition and DNA damaging chemotherapy. Whole-genome sequencing revealed a clonal hemizygous mutation in the Mre11 complex gene RAD50 that attenuated ATM signaling which in the context of Chk1 inhibition contributed, via synthetic lethality, to extreme sensitivity to irinotecan. As Mre11 mutations occur in a diversity of human tumors, the results suggest a tumor-specific combination therapy strategy whereby checkpoint inhibition in combination with DNA damaging chemotherapy is synthetically lethal in tumor but not normal cells with somatic mutations that impair Mre11 complex function. PMID:24934408

  19. The Structural Variation Is Associated with the Embryonic Lethality of a Novel Red Egg Mutant Fuyin-lre of Silkworm, Bombyx mori

    PubMed Central

    Li, Qiongyan; Zhao, Qiaoling; Yang, Weike; Zhu, Shuifen; Wu, Fang; He, Rongfan; Dong, Zhanpeng; Huang, Ping

    2015-01-01

    Bombyx mori presents several types of egg color mutations, all of which have been extensively discussed in sericulture. While the red egg mutation has been previously observed, lethal red-egg mutants have not been reported. In the present work, the red egg mutant Fuyin-lre (Fuyin-lethal red egg) was discovered from the Fuyin germplasm resource of B. mori. This mutant features red-colored eggs and embryonic lethality. Genetic analysis showed that Fuyin-lre follows recessive inheritance, with the red egg gene re governing the egg color, and the embryonic lethality of Fuyin-lre may be caused by mutations of other genes closely linked to re. Digital gene expression (DGE) was employed to compare the transcription profiles of Fuyin and Fuyin-lre eggs after 24 and 48 h of incubation. A total of 48 differentially expressed genes followed the same expression patterns in both groups at both time points (FDR < 0.01 and log 2 Ratio ? 1). Further analyses indicated that 8 out of the 48 genes (including re) were closely linked to re. These 8 genes were highly expressed in wild-type Fuyin and the red egg mutant re but showed nearly absent expression in Fuyin-lre. Sequencing of the re gene confirmed that the re gene itself does not induce embryonic lethality, and structure analysis showed that the structural variation of the region where the 8 genes were located may be associated with the embryonic lethality of Fuyin-lre. The present work provides a good foundation for future studies on the mechanism of embryonic lethality and embryonic development in Fuyin-lre. PMID:26030868

  20. Neonatal Lethality, Dwarfism, and Abnormal Brain Development in Dmbx1 Mutant Mice

    Microsoft Academic Search

    Akihira Ohtoshi; Richard R. Behringer

    2004-01-01

    Dmbx1 encodes a paired-like homeodomain protein that is expressed in developing neural tissues during mouse embryogenesis. To elucidate the in vivo role of Dmbx1, we generated two Dmbx1 mutant alleles. Dmbx1 lacks the homeobox and Dmbx1z is an insertion of a lacZ reporter gene. Dmbx1z appears to be a faithful reporter of Dmbx1 expression during embryogenesis and after birth. Dmbx1-lacZ

  1. Lethality in PARP-1/Ku80 double mutant mice reveals physiologicalsynergy during early embryogenesis

    SciTech Connect

    Henrie, Melinda S.; Kurimasa, Akihiro; Burma, Sandeep; Menissier-de Murcia, Josiane; de Murcia, Gilbert; Li, Gloria C.; Chen,David J.

    2002-09-24

    Ku is an abundant heterodimeric nuclear protein, consisting of 70-kDa and 86-kDa tightly associated subunits that comprise the DNA binding component of DNA-dependent protein kinase. Poly(ADP)ribose polymerase-1 (PARP-1) is a 113-kDa protein that catalyzes the synthesis of poly(ADP-ribose) on target proteins. Both Ku and PARP-1 recognize and bind to DNA ends. Ku functions in the non-homologous end joining (NHEJ) repair pathway whereas PARP-1 functions in the single strand break repair and base excision repair (BER) pathways. Recent studies have revealed that PARP-1 and Ku80 interact in vitro. To determine whether the association of PARP-1 and Ku80 has any physiological significance or synergistic function in vivo, mice lacking both PARP-1 and Ku80 were generated. The resulting offspring died during embryonic development displaying abnormalities around the gastrulation stage. In addition, PARP-1-/-Ku80-/- cultured blastocysts had an increased level of apoptosis. These data suggest that the functions of both Ku80 and PARP-1 are essential for normal embryogenesis and that a loss of genomic integrity leading to cell death through apoptosis is likely the cause of the embryonic lethality observed in these mice.

  2. Pathogenesis of Lethal Cardiac Arrhythmias in Mecp2 Mutant Mice: Implication for Therapy in Rett Syndrome

    PubMed Central

    McCauley, Mark D.; Wang, Tiannan; Mike, Elise; Herrera, Jose; Beavers, David L.; Huang, Teng-Wei; Ward, Christopher S.; Skinner, Steven; Percy, Alan K.; Glaze, Daniel G.; Wehrens, Xander H. T.; Neul, Jeffrey L.

    2013-01-01

    Rett Syndrome is a neurodevelopmental disorder typically caused by mutations in Methyl-CpG-Binding Protein 2 (MECP2) in which 26% of deaths are sudden and of unknown cause. To explore the hypothesis that these deaths may be due to cardiac dysfunction, we characterized the electrocardiograms (ECGs) in 379 people with Rett syndrome and found that 18.5% show prolongation of the corrected QT interval (QTc), indicating a repolarization abnormality that can predispose to the development of an unstable fatal cardiac rhythm. Male mice lacking MeCP2 function, Mecp2Null/Y, also have prolonged QTc and show increased susceptibility to induced ventricular tachycardia. Female heterozygous null mice, Mecp2Null/+, show an age-dependent prolongation of QTc associated with ventricular tachycardia and cardiac-related death. Genetic deletion of MeCP2 function in only the nervous system was sufficient to cause long QTc and ventricular tachycardia, implicating neuronally-mediated changes to cardiac electrical conduction as a potential cause of ventricular tachycardia in Rett syndrome. The standard therapy for prolonged QTc in Rett syndrome, ?-adrenergic receptor blockers, did not prevent ventricular tachycardia in Mecp2Null/Y mice. To determine whether an alternative therapy would be more appropriate, we characterized cardiomyocytes from Mecp2Null/Y mice and found increased persistent sodium current, which was normalized when cells were treated with the sodium channel-blocking anti-seizure drug phenytoin. Treatment with phenytoin reduced both QTc and sustained ventricular tachycardia in Mecp2Null/Y mice. These results demonstrate that cardiac abnormalities in Rett syndrome are secondary to abnormal nervous system control, which leads to increased persistent sodium current. Our findings suggest that treatment in people with Rett syndrome would be more effective if it targeted the increased persistent sodium current in order to prevent lethal cardiac arrhythmias. PMID:22174313

  3. sigE facilitates the adaptation of Bordetella bronchiseptica to stress conditions and lethal infection in immunocompromised mice

    PubMed Central

    2012-01-01

    Background The cell envelope of a bacterial pathogen can be damaged by harsh conditions in the environment outside a host and by immune factors during infection. Cell envelope stress responses preserve the integrity of this essential compartment and are often required for virulence. Bordetella species are important respiratory pathogens that possess a large number of putative transcription factors. However, no cell envelope stress responses have been described in these species. Among the putative Bordetella transcription factors are a number of genes belonging to the extracytoplasmic function (ECF) group of alternative sigma factors, some of which are known to mediate cell envelope stress responses in other bacteria. Here we investigate the role of one such gene, sigE, in stress survival and pathogenesis of Bordetella bronchiseptica. Results We demonstrate that sigE encodes a functional sigma factor that mediates a cell envelope stress response. Mutants of B. bronchiseptica strain RB50 lacking sigE are more sensitive to high temperature, ethanol, and perturbation of the envelope by SDS-EDTA and certain ?-lactam antibiotics. Using a series of immunocompromised mice deficient in different components of the innate and adaptive immune responses, we show that SigE plays an important role in evading the innate immune response during lethal infections of mice lacking B cells and T cells. SigE is not required, however, for colonization of the respiratory tract of immunocompetent mice. The sigE mutant is more efficiently phagocytosed and killed by peripheral blood polymorphonuclear leukocytes (PMNs) than RB50, and exhibits decreased cytotoxicity toward macrophages. These altered interactions with phagocytes could contribute to the defects observed during lethal infection. Conclusions Much of the work on transcriptional regulation during infection in B. bronchiseptica has focused on the BvgAS two-component system. This study reveals that the SigE regulon also mediates a discrete subset of functions associated with virulence. SigE is the first cell envelope stress-sensing system to be described in the bordetellae. In addition to its role during lethal infection of mice deficient in adaptive immunity, our results indicate that SigE is likely to be important for survival in the face of stresses encountered in the environment between hosts. PMID:22897969

  4. Study of radiosensitive Drosophila lines. XI. Induction of recessive sex-linked lethal mutations in females of the mutant line rad(2)201/sup G1/

    SciTech Connect

    Varentsova, E.R.

    1986-05-01

    The authors have studied the frequency of occurrence of recessive sex-linked lethal mutations (RSLLM) after treatment of the females with ..gamma..-rays as a function of the dose (from 5 to 20 Gy) and oogenesis stage. They have shown that within the dose range used the oocytes of the 14th and 7th development stage are more sensitive in females of the mutant line than in those of the control. They detected significant differences in the frequency of occurrence of RSLLM between the 14th and 7th stages of development of oocytes for both Drosophila lines investigated.

  5. The Arabidopsis acbp1acbp2 double mutant lacking acyl-CoA-binding proteins ACBP1 and ACBP2 is embryo lethal

    PubMed Central

    Chen, Qin-Fang; Xiao, Shi; Qi, Wenqing; Mishra, Girish; Ma, Jinyu; Wang, Mingfu; Chye, Mee-Len

    2014-01-01

    Summary In Arabidopsis thaliana, the amino acid sequences of membrane-associated acyl-CoA-binding proteins ACBP1 and ACBP2 are highly-conserved. We have previously shown that in developing seeds, ACBP1 accumulates in the cotyledonary cells of embryos and ACBP1 was proposed to be involved in lipid transfer. We show here by immunolocalization using ACBP2-specific antibodies, that ACBP2 is also expressed in the embryos at various stages of seed development in Arabidopsis.Phenotypic analyses of acbp1 and acbp2 single mutants revealed that knockout of either ACBP1 or ACBP2 alone did not affect their life cycle since both single mutants exhibited normal growth and development similar to wild type. However, the acbp1acbp2 double mutant was embryo lethal and was also defective in callus induction.On lipid and acyl-CoA profiling analyses, siliques but not leaves of the acbp1 mutant were shown to accumulate galactolipid monogalactosyldiacylglycerol (MGDG) and 18:0-CoA but the levels of most polyunsaturated species of phospholipids such as phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylinositol (PI) and phosphatidylserine (PS) had declined.Since recombinant ACBP1 and ACBP2 bind unsaturated PC and acyl-CoA esters in vitro, we propose that ACBP1 and ACBP2 are essential in lipid transfer during early embryogenesis in Arabidopsis. PMID:20345632

  6. Postembryonic Seedling Lethality in the Sterol-Deficient Arabidopsis cyp51A2 Mutant Is Partially Mediated by the Composite Action of Ethylene and Reactive Oxygen Species1[W][OA

    PubMed Central

    Kim, Ho Bang; Lee, Hyoungseok; Oh, Chang Jae; Lee, Hae-Youn; Eum, Hyang Lan; Kim, Hyung-Sae; Hong, Yoon-Pyo; Lee, Yi; Choe, Sunghwa; An, Chung Sun; Choi, Sang-Bong

    2010-01-01

    Seedling-lethal phenotypes of Arabidopsis (Arabidopsis thaliana) mutants that are defective in early steps in the sterol biosynthetic pathway are not rescued by the exogenous application of brassinosteroids. The detailed molecular and physiological mechanisms of seedling lethality have yet to be understood. Thus, to elucidate the underlying mechanism of lethality, we analyzed transcriptome and proteome profiles of the cyp51A2 mutant that is defective in sterol 14?-demethylation. Results revealed that the expression levels of genes involved in ethylene biosynthesis/signaling and detoxification of reactive oxygen species (ROS) increased in the mutant compared with the wild type and, thereby, that the endogenous ethylene level also increased in the mutant. Consistently, the seedling-lethal phenotype of the cyp51A2 mutant was partly attenuated by the inhibition of ethylene biosynthesis or signaling. However, photosynthesis-related genes including Rubisco large subunit, chlorophyll a/b-binding protein, and components of photosystems were transcriptionally and/or translationally down-regulated in the mutant, accompanied by the transformation of chloroplasts into gerontoplasts and a reduction in both chlorophyll contents and photosynthetic activity. These characteristics observed in the cyp51A2 mutant resemble those of leaf senescence. Nitroblue tetrazolium staining data revealed that the mutant was under oxidative stress due to the accumulation of ROS, a key factor controlling both programmed cell death and ethylene production. Our results suggest that changes in membrane sterol contents and composition in the cyp51A2 mutant trigger the generation of ROS and ethylene and eventually induce premature seedling senescence. PMID:19915013

  7. An Arabidopsis Mutant Tolerant to Lethal Ultraviolet-B Levels Shows Constitutively Elevated Accumulation of Flavonoids and Other Phenolics

    Microsoft Academic Search

    Kim Bieza; Rodrigo Lois

    2001-01-01

    The isolation and characterization of mutants hypersensitive to ultraviolet (UV) radiation has been a powerful tool to learn about the mechanisms that protect plants against UV-induced damage. To increase our understanding of the various mechanisms of defense against UVB radiation, we searched for mutations that would increase the level of tolerance of Arabidopsis plants to UV radiation. We describe a

  8. Lethal phenotype in conditional late-onset arginase 1 deficiency in the mouse.

    PubMed

    Kasten, Jennifer; Hu, Chuhong; Bhargava, Ragini; Park, Hana; Tai, Denise; Byrne, James A; Marescau, Bart; De Deyn, Peter P; Schlichting, Lisa; Grody, Wayne W; Cederbaum, Stephen D; Lipshutz, Gerald S

    2013-11-01

    Human arginase deficiency is characterized by hyperargininemia and infrequent episodes of hyperammonemia, which lead to neurological impairment with spasticity, loss of ambulation, seizures, and severe mental and growth retardation; uncommonly, patients suffer early death from this disorder. In a murine targeted knockout model, onset of the phenotypic abnormality is heralded by weight loss at around day 15, and death occurs typically by postnatal day 17 with hyperargininemia and markedly elevated ammonia. This discrepancy between the more attenuated juvenile-onset human disease and the lethal neonatal murine model has remained suboptimal for studying and developing therapy for the more common presentation of arginase deficiency. These investigations aimed to address this issue by creating an adult conditional knockout mouse to determine whether later onset of arginase deficiency also resulted in lethality. Animal survival and ammonia levels, body weight, circulating amino acids, and tissue arginase levels were examined as outcome parameters after widespread Cre-recombinase activation in a conditional knockout model of arginase 1 deficiency. One hundred percent of adult female and 70% of adult male mice died an average of 21.0 and 21.6 days, respectively, after the initiation of tamoxifen administration. Animals demonstrated elevated circulating ammonia and arginine at the onset of phenotypic abnormalities. In addition, brain and liver amino acids demonstrated abnormalities. These studies demonstrate that (a) the absence of arginase in adult animals results in a disease profile (leading to death) similar to that of the targeted knockout and (b) the phenotypic abnormalities seen in the juvenile-onset model are not exclusive to the age of the animal but instead to the biochemistry of the disorder. This adult model will be useful for developing gene- and cell-based therapies for this disorder that will not be limited by the small animal size of neonatal therapy and for developing a better understanding of the characteristics of hyperargininemia. PMID:23920045

  9. Marker rescue mapping of the combined Condit/Dales collection of temperature sensitive vaccinia virus mutants

    PubMed Central

    Kato, Sayuri E. M.; Moussatche, Nissin; D’Costa, Susan M.; Bainbridge, Travis W.; Prins, Cindy; Strahl, Audra L.; Shatzer, Amber N.; Brinker, Alyson J.; Kay, Nicole E.; Condit, Richard C.

    2008-01-01

    Complementation analysis of the combined Condit/Dales collection of vaccinia virus temperature sensitive mutants has been reported (Lackner et al., 2003), however not all complementation groups have previously been assigned to single genes on the viral genome. We have used marker rescue to map at least one representative of each complementation group to a unique viral gene. The final combined collection contains 124 temperature sensitive mutants affecting 38 viral genes, plus five double mutants. PMID:18314155

  10. A microfluidic live cell assay to study anthrax toxin induced cell lethality assisted by conditioned medium.

    PubMed

    Shen, Jie; Cai, Changzu; Yu, Zhilong; Pang, Yuhong; Zhou, Ying; Qian, Lili; Wei, Wensheng; Huang, Yanyi

    2015-01-01

    It is technically challenging to investigate the function of secreted protein in real time by supply of conditioned medium that contains secreted protein of interest. The internalization of anthrax toxin is facilitated by a secreted protein Dickkopf-1 (DKK1) and its receptor, and eventually leads to cell lethality. To monitor the dynamic interplay between these components in live cells, we use an integrated microfluidic device to perform the cell viability assays with real-time controlled culture microenvironment in parallel. Conditioned medium, which contains the secreted proteins from specific cell lines, can be continuously pumped towards the cells that exposed to toxin. The exogenous DKK1 secreted from distant cells is able to rescue the sensitivity to toxin for those DKK1-knocked-down cells. This high-throughput assay allows us to precisely quantify the dynamic interaction between key components that cause cell death, and provide independent evidence of the function of DKK1 in the complex process of anthrax toxin internalization. PMID:25731605

  11. Combination Therapy Using Chimeric Monoclonal Antibodies Protects Mice from Lethal H5N1 Infection and Prevents Formation of Escape Mutants

    PubMed Central

    He, Fang; Hongliang, Qian; Ho, Hui-Ting; Qiang, Jia; TaoMeng; Goutama, Michael; Kwang, Jimmy

    2009-01-01

    Background Given that there is a possibility of a human H5N1 pandemic and the fact that the recent H5N1 viruses are resistant to the anti-viral drugs, newer strategies for effective therapy are warranted. Previous studies show that single mAbs in immune prophylaxis can be protective against H5N1 infection. But a single mAb may not be effective in neutralization of a broad range of different strains of H5N1 and control of potential neutralization escape mutants. Methods/Principal Findings We selected two mAbs which recognized different epitopes on the hemagglutinin molecule. These two mAbs could each neutralize in vitro escape mutants to the other and in combination could effectively neutralize viruses from clades 0, 1, 2.1, 2.2, 2.3, 4, 7 and 8 of influenza A H5N1 viruses. This combination of chimeric mAbs when administered passively, pre or post challenge with 10 MLD50 (50% mouse lethal dose) HPAI H5N1 influenza A viruses could protect 100% of the mice from two different clades of viruses (clades 1 and 2.1). We also tested the efficacy of a single dose of the combination of mAbs versus two doses. Two doses of the combination therapy not only affected early clearance of the virus from the lung but could completely prevent lung pathology of the H5N1 infected mice. No escape variants were detected after therapy. Conclusions/Significance Our studies provide proof of concept that the synergistic action of two or more mAbs in combination is required for preventing the generation of escape mutants and also to enhance the therapeutic efficacy of passive therapy against H5N1 infection. Combination therapy may allow for a lower dose of antibody to be administered for passive therapy of influenza infection and hence can be made available at reduced economic costs during an outbreak. PMID:19478856

  12. How killed enterobacterial cultures can activate living organisms to resist lethal agents or conditions.

    PubMed

    Rowbury, Robin J

    2003-01-01

    A major aim in many areas of microbiology is to ensure sterility, and even where this is impossible, to reduce the number of viable organisms occurring in particular environments to an absolute minimum. This applies in the aquatic environment, where e.g. water treatment must ensure as complete absence of viable microbes as possible. It is also crucial in food processing and production; many food constituents contain appreciable numbers of viable organisms, even potential pathogens, and the number must be greatly reduced and in many situations, the presence of viable organisms totally abolished. Cleaning of food production components and surfaces must also kill associated microbes. In domestic, hospital and commercial situations, similar disinfection is critical. Ultimately, the aim is to ensure, if possible, sterility, with the assurance that microbial problems cannot occur if organisms are absent. Additionally, however, it has been implicitly assumed that killed organisms and even killed cultures cannot (except in minor and trivial ways) influence the behaviour of living organisms that later enter the environment. The work reviewed here challenges that view and in fact disproves it. The findings described show that killed enterobacterial cultures, which prior to killing had phenotypically gained the ability to resist potentially lethal stresses, can pass on such ability to living organisms that later enter their environment i.e. that such killed cultures can convey a baleful legacy to living ones. This phenomenon is so widespread that it is clear that it has significance for enterobacterial survival in natural waters, in foods and in food production, in the domestic, commercial and hospital situation, and in the animal and human body. In fact, in this last area, the likely effect of killed cultures appears to be of appreciable public health importance. Here, the ability of appropriate killed cultures to transfer tolerance to acidity, alkalinity and thermal stress is described, as well as their ability to pass on sensitisation to acid and alkali. Other work reviewed suggests that killed cultures can almost certainly transfer the ability to tolerate hydrogen peroxide, ultraviolet irradiation and metal ions. The serious implications of this phenomenon are further emphasised by the fact that numerous killing methods produce cultures effective in tolerance response transfer. All the evidence suggests that it is extracellular components (extracellular sensing components, ESCs, and extracellular induction components, EICs), in the killed cultures which are involved in stress response transfer, and that the actual stress response induction process depends on interaction of living organisms with EICs from the killed cultures. It is of note that ESCs and EICs survive in killed cultures because of their extreme resistance to irreversible inactivation by lethal levels of stressing agents and conditions. This is in contrast to the fact that EC activation, namely the conversion of ESC to EIC occurs on exposure to very low levels of stressors. Not only is this the case, but in fact high levels of stressors (e.g. those that kill organisms) generally fail to convert ESC to EIC. PMID:15079995

  13. Producing Conditional Mutants for Studying Plant Microtubule Function

    SciTech Connect

    Richard Cyr

    2009-09-29

    The cytoskeleton, and in particular its microtubule component, participates in several processes that directly affect growth and development in higher plants. Normal cytoskeletal function requires the precise and orderly arrangement of microtubules into several cell cycle and developmentally specific arrays. One of these, the cortical array, is notable for its role in directing the deposition of cellulose (the most prominent polymer in the biosphere). An understanding of how these arrays form, and the molecular interactions that contribute to their function, is incomplete. To gain a better understanding of how microtubules work, we have been working to characterize mutants in critical cytoskeletal genes. This characterization is being carried out at the subcellular level using vital microtubule gene constructs. In the last year of funding colleagues have discovered that gamma-tubulin complexes form along the lengths of cortical microtubules where they act to spawn new microtubules at a characteristic 40 deg angle. This finding complements nicely the finding from our lab (which was funded by the DOE) showing that microtubule encounters are angle dependent; high angles encounters results in catastrophic collisions while low angle encounters result in favorable zippering. The finding of a 40 deg spawn of new microtubules from extant microtubule, together with aforementioned rules of encounters, insures favorable co-alignment in the array. I was invited to write a New and Views essay on this topic and a PDF is attached (News and Views policy does not permit funding acknowledgments and so I was not allowed to acknowledge support from the DOE).

  14. Conditional Genealogies and the Age of a Neutral Mutant

    Microsoft Academic Search

    Carsten Wiuf; Peter Donnelly

    1999-01-01

    This paper is concerned with the structure of the genealogy of a sample in which it is observed that some subset of chromosomes carries a particular mutation, assumed to have arisen uniquely in the history of the population. A rigorous theoretical study of this conditional genealogy is given using coalescent methods. Particular results include the mean, variance, and density of

  15. Studies of muscle proteins in embryonic myocardial cells of cardiac lethal mutant mexican axolotls (Ambystoma mexicanum) by use of heavy meromyosin binding and sodium dodecyl sulfate polyacrylamide gel electrophoresis

    PubMed Central

    1976-01-01

    In the Mexican axolotl Ambystoma mexicanum recessive mutant gene c, by way of abnormal inductive processes from surrounding tissues, results in an absence of embryonic heart function. The lack of contractions in mutant heart cells apparently results from their inability to form normally organized myofibrils, even though a few actin-like (60-A) and myosin-like (150-A) filaments are present. Amorphous "proteinaceous" collections are often visible. In the present study, heavy meromyosin (HMM) treatment of mutant heart tissue greatly increases the number of thin filaments and decorates them in the usual fashion, confirming that they are actin. The amorphous collections disappear with the addition of HMM. In addition, an analysis of the constituent proteins of normal and mutant embryonic hearts and other tissues is made by sodium dodecyl sulfate (SDS) gel electrophoresis. These experiments are in full agreement with the morphological and HMM binding studies. The gels show distinct 42,000-dalton bands for both normal and mutant hearts, supporting the presence of normal actin. During early developmental stages (Harrison's stage 34) the cardiac tissues in normal and mutant siblings have indistinguishable banding patterns, but with increasing development several differences appear. Myosin heavy chain (200,000 daltons) increases substantially in normal hearts during development but very little in mutants. Even so the quantity of 200,000-dalton protein in mutant hearts is significantly more than in any of the nonmuscle tissues studied (i.e. gut, liver, brain). Unlike normal hearts, the mutant hearts lack a prominent 34,000-dalton band, indicating that if mutants contain muscle tropomyosin at all, it is present in drastically reduced amounts. Also, mutant hearts retain large amounts of yolk proteins at stages when the platelets have virtually disappeared from normal hearts. The morphologies and electrophoresis patterns of skeletal muscle from normal and mutant siblings are identical, confirming that gene c affects only heart muscle differentiation and not skeletal muscle. The results of the study suggest that the precardiac mesoderm in cardiac lethal mutant axolotl embryos initiates but then fails to complete its differentiation into functional muscle tissue. It appears that this single gene mutation, by way of abnormal inductive processes, affects the accumulation and organization of several different muscle proteins, including actin, myosin, and tropomyosin. PMID:1107335

  16. The Live Attenuated Actinobacillus pleuropneumoniae Triple-Deletion Mutant ?apxIC ?apxIIC ?apxIV-ORF1 Strain, SLW05, Immunizes Pigs against Lethal Challenge with Haemophilus parasuis

    PubMed Central

    Fu, Shulin; Ou, Jiwen; Zhang, Minmin; Xu, Juan; Liu, Huazhen; Liu, Jinlin; Yuan, Fangyan; Chen, Huanchun

    2013-01-01

    Haemophilus parasuis and Actinobacillus pleuropneumoniae both belong to the family Pasteurellaceae and are major respiratory pathogens that cause large economic losses in the pig industry worldwide. We previously constructed an attenuated A. pleuropneumoniae serovar 1 live vaccine prototype, SLW05 (?apxIC ?apxIIC ?apxIV-ORF1), which is able to produce nontoxic but immunogenic ApxIA, ApxIIA, and ApxIVA. This triple-deletion mutant strain was shown to elicit protective immunity against virulent A. pleuropneumoniae. In the present study, we investigated whether immunization with SLW05 could also protect against lethal challenge with virulent H. parasuis SH0165 (serovar 5) or MD0322 (serovar 4). The SLW05 strain was found to elicit a strong humoral antibody response in pigs and to confer significant protection against challenge with a lethal dose of H. parasuis SH0165 or MD0322. IgG subtype analysis revealed that SLW05 induces a bias toward a Th1-type immune response and stimulates interleukin 2 (IL-2) and gamma interferon (IFN-?) production. Moreover, antisera from SLW05-vaccinated pigs efficiently inhibited both A. pleuropneumoniae and H. parasuis growth in a whole-blood assay. This is the first report that a live attenuated A. pleuropneumoniae vaccine with SLW05 can protect against lethal H. parasuis infection, which provides a novel approach for developing an attenuated H. parasuis vaccine. PMID:23220998

  17. Mosaic mutant Analysis with Spatial and Temporal control of Recombination (MASTR): a new technique for determining the fate of mutant cells using conditional floxed alleles in mice

    PubMed Central

    Lao, Zhimin; Raju, G. Praveen; Bai, C. Brian; Joyner, Alexandra L.

    2012-01-01

    SUMMARY Mosaic mutant analysis, the study of cellular defects in scattered mutant cells in a wild type environment, is a powerful approach for identifying critical functions of genes and has been applied extensively to invertebrate model organisms. A novel and highly versatile technique was developed in mouse, Mosaic mutant Analysis with Spatial and Temporal control of Recombination (MASTR), that utilizes the increasing number of floxed alleles and simultaneously combines conditional gene mutagenesis and cell marking for fate analysis. A targeted allele (R26MASTR) was engineered that expresses a GFPcre fusion protein following FLP-mediated recombination that serves the dual function of deleting floxed alleles and marking mutant cells with GFP. Within 24 hr of tamoxifen administration to R26MASTR mice carrying a new inducible FlpoER transgene and a floxed allele nearly all GFP-expressing cells have a mutant allele. The fate of single cells lacking FGF8 or SHH signaling in the developing hindbrain was analyzed using MASTR and revealed there is only a short time window when neural progenitors require FGFR1 for viability, and that granule cell precursors differentiate rapidly when SMO is lost. MASTR is a powerful tool that provides cell type specific (spatial) and temporal marking of mosaic mutant cells that is broadly applicable to developmental, cancer and adult stem cell studies. PMID:22884371

  18. Thiamine Deficiency in Self-Induced Refeeding Syndrome, an Undetected and Potentially Lethal Condition

    PubMed Central

    Hershkowitz, Einat; Reshef, Alon; Munich, Olga; Yosefi, Bracha; Markel, Arie

    2014-01-01

    Rapid restoration of nutrients and electrolytes after prolonged starvation could result in a life threatening condition characterized by sensory and neurological dysfunction and severe metabolic imbalance that has been designated as refeeding syndrome. Its diagnosis is frequently missed resulting in severe complications and even death. We describe a 25-years-old female patient with mental disorders and severe malnutrition who developed severe clinical manifestations and biochemical abnormalities characteristic of the refeeding syndrome, after restarting oral feeding on her own. Schizophrenia was later diagnosed. Increased awareness of this condition and its complications is necessary to prevent its detrimental complications. PMID:25614745

  19. Growth stimulation in inflorescences of an Arabidopsis tubulin mutant under microgravity conditions in space.

    PubMed

    Hoson, T; Soga, K; Wakabayashi, K; Hashimoto, T; Karahara, I; Yano, S; Tanigaki, F; Shimazu, T; Kasahara, H; Masuda, D; Kamisaka, S

    2014-01-01

    Cortical microtubules are involved in plant resistance to hypergravity, but their roles in resistance to 1 g gravity are still uncertain. To clarify this point, we cultivated an Arabidopsis ?-tubulin 6 mutant (tua6) in the Cell Biology Experiment Facility on the Kibo Module of the International Space Station, and analyzed growth and cell wall mechanical properties of inflorescences. Growth of inflorescence stems was stimulated under microgravity conditions, as compared with ground and on-orbit 1 g conditions. The stems were 10-45% longer and their growth rate 15-55% higher under microgravity conditions than those under both 1 g conditions. The degree of growth stimulation tended to be higher in the tua6 mutant than the wild-type Columbia. Under microgravity conditions, the cell wall extensibility in elongating regions of inflorescences was significantly higher than the controls, suggesting that growth stimulation was caused by cell wall modifications. No clear differences were detected in any growth or cell wall property between ground and on-orbit 1 g controls. These results support the hypothesis that cortical microtubules generally play an important role in plant resistance to the gravitational force. PMID:24148142

  20. Chromosome condensation may enhance X-ray-related cell lethality in a temperature-sensitive mutant (tsBN2) of baby hamster kidney cells (BHK21)

    SciTech Connect

    Sasaki, H.; Nishimoto, T.

    1987-03-01

    In the tsBN2 cell line, which has a temperature-sensitive defect in the regulatory mechanism for chromosome condensation, the lethal effect of X rays was enhanced by incubating the cells at a nonpermissive temperature (40 degrees C) following X irradiation. This enhancement was suppressed in the presence of cycloheximide, which inhibits induction of premature chromosome condensation. The findings obtained in the case of delayed incubation at 40 degrees C and in synchronized cells indicate that X-ray-related potentially lethal damage, which can be expressed by chromosome condensation, is produced in the cells at any stage of the cell cycle, but it is repairable for all cells except those at around the late G2-M phase, where chromosome condensation occurs at a permissive temperature (33.5 degrees C). These observations suggest that the high sensitivity of late G2-M cells to X rays is caused by the events associated with chromosome condensation.

  1. Chromosome condensation may enhance X-ray-related cell lethality in a temperature-sensitive mutant (tsBN2) of baby hamster kidney cells (BHK21)

    Microsoft Academic Search

    H. Sasaki; T. Nishimoto

    1987-01-01

    In the tsBN2 cell line, which has a temperature-sensitive defect in the regulatory mechanism for chromosome condensation, the lethal effect of X rays was enhanced by incubating the cells at a nonpermissive temperature (40 degrees C) following X irradiation. This enhancement was suppressed in the presence of cycloheximide, which inhibits induction of premature chromosome condensation. The findings obtained in the

  2. Mouse Mutants Lacking the Type 2 IGF Receptor (IGF2R) Are Rescued from Perinatal Lethality in Igf2and Igf1rNull Backgrounds

    Microsoft Academic Search

    Thomas Ludwig; Jonathan Eggenschwiler; Peter Fisher; A. Joseph D'Ercole; Marsha L. Davenport; Argiris Efstratiadis

    1996-01-01

    The cation-dependent and cation-independent mannose 6-phosphate receptors (CD- and CI-MPRs) bind the phosphomannosyl recognition marker of lysosomal hydrolases, but in mammals the latter also interacts with insulin-like growth factor II (IGF-II). While IGF signaling is mediated by the type 1 IGF receptor (IGF1R), the type 2 receptor (IGF2R\\/CI-MPR) serves IGF-II turnover. Mouse mutants inheriting maternally a targeted disruption of the

  3. Chromoplast development in a carotenoid mutant of maize

    Microsoft Academic Search

    Björn Walles

    1971-01-01

    Summary The lethal recessive mutantlycopenic in maize is characterized by the synthesis of lycopene instead of the normal carotenoids. At normal conditions of illumination it loses chlorophyll by photo-oxidation. Seedlings of this mutant and of normal maize were grown at light intensities of 25–30 lux and 500–30,000 lux. Their plastid development was studied by electron microscopy.

  4. Bactericidal activity of PA-824 against Mycobacterium tuberculosis under anaerobic conditions and computational analysis of its novel analogues against mutant Ddn receptor

    PubMed Central

    2013-01-01

    Background The resurgence of multi-drug resistant tuberculosis (MDR-TB) and HIV associated tuberculosis (TB) are of serious global concern. To contain this situation, new anti-tuberculosis drugs and reduced treatment regimens are imperative. Recently, a nitroimidazole, PA-824, has been shown to be active against both replicating and non-replicating bacteria. It is activated by the enzyme Deazaflavin-dependent nitroreductase (Ddn) present in Mycobacterium tuberculosis which catalyzes the reduction of PA-824, resulting in the release of lethal reactive nitrogen species (RNS) within the bacteria. In this context, PA-824 was analyzed for its activity against latent tuberculosis under anaerobic conditions and compared with rifampicin (RIF) and pyrazinamide (PZA). Recent mutagenesis studies have identified A76E mutation which affects the above mentioned catalysis and leads to PA-824 resistance. Hence, novel analogues which could cope up with their binding to mutant Ddn receptor were also identified through this study. Results PA-824 at an optimum concentration of 12.5 ?g/ml showed enhanced bactericidal activity, resulting in 0 CFU/ml growth when compared to RIF and PZA at normal pH and anaerobic condition. Further docking studies revealed that a combinatorial structure of PA-824 conjugated with moxifloxacin (ligand 8) has the highest binding affinity with the wild type and mutant Ddn receptor. Conclusions PA-824 has been demonstrated to have better activity under anaerobic condition at 12.5 ?g/ml, indicating an optimized dose that is required for overcoming the detoxifying mechanisms of M. tuberculosis and inducing its death. Further, the development of resistance through A76E mutation could be overcome through the in silico evolved ligand 8. PMID:24083570

  5. Biochemical dissection of diageotropica and Never ripe tomato mutants to Cd-stressful conditions.

    PubMed

    Gratão, Priscila L; Monteiro, Carolina C; Carvalho, Rogério F; Tezotto, Tiago; Piotto, Fernando A; Peres, Lázaro E P; Azevedo, Ricardo A

    2012-07-01

    In order to further address the modulation of signaling pathways of stress responses and their relation to hormones, we used the ethylene-insensitive Never ripe (Nr) and the auxin-insensitive diageotropica (dgt) tomato mutants. The two mutants and the control Micro-Tom (MT) cultivar were grown over a 40-day period in the presence of Cd (0.2 mM CdCl? and 1 mM CdCl?). Lipid peroxidation, leaf chlorophyll, proline content, Cd content and antioxidant enzyme activities in roots, leaves and fruits were determined. The overall results indicated that the MT genotype had the most pronounced Cd damage effects while Nr and dgt genotypes might withstand or avoid stress imposed by Cd. This fact may be attributed, at least in part, to the fact that the known auxin-stimulated ethylene production is comprised in dgt plants. Conversely, the Nr genotype was more affected by the Cd imposed stress than dgt, which may be explained by the fact that Nr retains a partial sensitivity to ethylene. These results add further information that should help unraveling the relative importance of ethylene in regulating the cell responses to stressful conditions. PMID:22609458

  6. Heavy ion effects on cells: survival of a temperature-conditional repair mutant of yeast.

    PubMed

    Kiefer, J; Schneider, E

    1991-06-01

    The temperature-conditional double-strand break repair mutant rad 54-3 of the yeast Saccharomyces cerevisiae was exposed to Ar, Ti and U ions with LET values between 900 and 15,000 keV/micron. Survival was assessed after incubation at the permissive (23 degrees C) and the restrictive temperature (36 degrees C) in aliquots of the same sample. Repair could be demonstrated in all instances, although to a somewhat reduced extent with the heavy ions as compared to X-rays. The results suggest that very densely ionizing radiations do not produce lesions which are irreparable per se, but that their ultimate fate depends on the particular repair system which may be different in different cell types. PMID:1677385

  7. Neutral lipid accumulation at elevated temperature in conditional mutants of two microalgae species.

    PubMed

    Yao, Shuo; Brandt, Anders; Egsgaard, Helge; Gjermansen, Claes

    2012-12-01

    Triacylglycerols, an energy storage compound in microalgae, are known to be accumulated after nitrogen starvation of microalgae cells. Microalgae could be of importance for future biodiesel production due to their fast growth rate and high oil content. In collections of temperature sensitive mutants of Chlamydomonas reinhardtii and Chlorella vulgaris, nine out of fourty-one mutants in C. reinhardtii and eleven out of fifty-three mutants in C. vulgaris contained increased amounts of neutral lipids, predominantly as triacylglycerols. Upon temperature induced cell-cycle arrest, these mutants showed enlarged cellular volume compared with the wild type. The C. reinhardtii mutants were analyzed further and one type of mutants displayed a shift in lipid composition from polar membrane lipids to neutral lipids after a temperature up-shift, while the second type of mutants accumulated more total lipid per cell, predominantly as neutral lipids as compared with the wild type. Three C. reinhardtii mutants were analyzed further and found to be arrested after DNA synthesis but prior to cell division in the cell cycle. These mutants will be useful in order to further understand neutral lipid accumulation in microalgae and suggest possibilities for biodiesel production by specific induction of lipid accumulation in miroalgal cultures by cell-cycle inhibition. PMID:23085584

  8. Autophagy in yeast demonstrated with proteinase-deficient mutants and conditions for its induction

    PubMed Central

    1992-01-01

    For determination of the physiological role and mechanism of vacuolar proteolysis in the yeast Saccharomyces cerevisiae, mutant cells lacking proteinase A, B, and carboxypeptidase Y were transferred from a nutrient medium to a synthetic medium devoid of various nutrients and morphological changes of their vacuoles were investigated. After incubation for 1 h in nutrient-deficient media, a few spherical bodies appeared in the vacuoles and moved actively by Brownian movement. These bodies gradually increased in number and after 3 h they filled the vacuoles almost completely. During their accumulation, the volume of the vacuolar compartment also increased. Electron microscopic examination showed that these bodies were surrounded by a unit membrane which appeared thinner than any other intracellular membrane. The contents of the bodies were morphologically indistinguishable from the cytosol; these bodies contained cytoplasmic ribosomes, RER, mitochondria, lipid granules and glycogen granules, and the density of the cytoplasmic ribosomes in the bodies was almost the same as that of ribosomes in the cytosol. The diameter of the bodies ranged from 400 to 900 nm. Vacuoles that had accumulated these bodies were prepared by a modification of the method of Ohsumi and Anraku (Ohsumi, Y., and Y. Anraku. 1981. J. Biol. Chem. 256:2079-2082). The isolated vacuoles contained ribosomes and showed latent activity of the cytosolic enzyme glucose-6-phosphate dehydrogenase. These results suggest that these bodies sequestered the cytosol in the vacuoles. We named these spherical bodies "autophagic bodies." Accumulation of autophagic bodies in the vacuoles was induced not only by nitrogen starvation, but also by depletion of nutrients such as carbon and single amino acids that caused cessation of the cell cycle. Genetic analysis revealed that the accumulation of autophagic bodies in the vacuoles was the result of lack of the PRB1 product proteinase B, and disruption of the PRB1 gene confirmed this result. In the presence of PMSF, wild-type cells accumulated autophagic bodies in the vacuoles under nutrient-deficient conditions in the same manner as did multiple protease-deficient mutants or cells with a disrupted PRB1 gene. As the autophagic bodies disappeared rapidly after removal of PMSF from cultures of normal cells, they must be an intermediate in the normal autophagic process. This is the first report that nutrient-deficient conditions induce extensive autophagic degradation of cytosolic components in the vacuoles of yeast cells. PMID:1400575

  9. Conditional Lethality Yields a New Vaccine Strain of Listeria monocytogenes for the Induction of Cell-Mediated Immunity

    Microsoft Academic Search

    Zhongxia Li; Xinyan Zhao; Darren E. Higgins; Fred R. Frankel

    2005-01-01

    Listeria monocytogenes is a gram-positive intracellular pathogen that can enter phagocytic and nonphagocytic cells and colonize their cytosols. Taking advantage of this property to generate an intracellular vaccine delivery vector, we previously described a mutant strain of L. monocytogenes, dal dat, which is unable to synthesize cell wall by virtue of deletions in two genes (dal and dat) required for

  10. Comparative proteomic analysis of a Candida albicans DSE1 mutant under filamentous and non-filamentous conditions.

    PubMed

    Zohbi, Rasha; Wex, Brigitte; Khalaf, Roy A

    2014-11-01

    Candida albicans is a common opportunistic pathogen that causes a variety of diseases in immunocompromised hosts. In a pathogen, cell wall proteins are important virulence factors. We previously characterized Dse1 as a cell wall protein necessary for virulence and resistance to cell surface-disrupting agents, such as Calcofluor white, chitin deposition, proper adhesion and biofilm formation. In the absence of decomplexation, our objectives were to investigate differential proteomic expression of a DSE1 mutant strain compared to the wild-type strain. The strains were grown under filamentous and non-filamentous conditions. The extracted cell proteome was subjected to tryptic digest, followed by generation of peptide profiles using MALDI-TOF MS. Generated peptide profiles were analysed and unique peaks for each strain and growth condition mined against a Candida database, allowing protein identification. The DSE1 mutant was shown to lack the chitin biosynthesis protein Chs5, explaining the previously observed decrease in chitin biosynthesis. The wild-type strain expressed Pra1, involved in pH response and zinc acquisition, Atg15, a lipase involved in virulence, and Sod1, required for oxidative stress tolerance, in addition to proteins involved in protein biosynthesis, explaining the increase in total protein content observed compared to the mutants strain. The mutant, on the other hand, expressed glucoamylase 1, a cell wall glycoprotein involved in carbohydrate metabolism cell wall degradation and biofilm formation. As such, MALDI-TOF MS is a reliable technique in identifying mutant-specific protein expression in C. albicans. PMID:25231799

  11. Chinese hamster V79 cells harbor potentially lethal damage which is neither fixed nor repaired for long times after attaining maximal survival under growth conditions

    SciTech Connect

    Reddy, N.M.S.; Nori, D. [New York Hospital Medical Center of Queens, Flushing, NY (United States); Mayer, P.J.; Lange, C.S. [SUNY Health Science Center, Brooklyn, NY (United States)

    1995-03-01

    The kinetics of the repair and fixation of potentially lethal damage (PLD) was studied in log-phase Chinese hamster V79 cells. The postirradiation (10 Gy) survival of cells treated with hypertonic saline increased when these cells were incubated further in conditioned medium but not in growth medium, indicating that damage which is neither fixed by hypertonic saline nor amenable to repair in growth medium is nonetheless repaired in conditioned medium. Recovery of X-irradiated cells incubated in growth medium or in conditioned medium was maximal by about 70 min and was two times higher in conditioned medium than in growth medium. Cells incubated in growth medium for 70-120 min postirradiation continued to repair damage when subsequently shifted to conditioned medium only. Thus PLD is not fixed by the time the recovery plateau has been attained in growth medium, and this unfixed PLD can still be repaired when cells are shifted to conditioned medium. To study the kinetics of fixation of PLD (without hypertonic saline), the survival of cells incubated in growth medium for up to 9 h postirradiation was compared with that for cells incubated in conditioned medium. These results show that the damage was neither fixed nor misrepaired in growth medium but rather remained unrepaired for up to 2 h, and that damage fixation in growth medium does not begin until after 2 h and is completed by 6 h postirradiation. 21 refs., 4 figs., 1 tab.

  12. Development of Synthetic Lethality Anticancer Therapeutics

    PubMed Central

    2015-01-01

    The concept of synthetic lethality (the creation of a lethal phenotype from the combined effects of mutations in two or more genes) has recently been exploited in various efforts to develop new genotype-selective anticancer therapeutics. These efforts include screening for novel anticancer agents, identifying novel therapeutic targets, characterizing mechanisms of resistance to targeted therapy, and improving efficacies through the rational design of combination therapy. This review discusses recent developments in synthetic lethality anticancer therapeutics, including poly ADP-ribose polymerase inhibitors for BRCA1- and BRCA2-mutant cancers, checkpoint inhibitors for p53 mutant cancers, and small molecule agents targeting RAS gene mutant cancers. Because cancers are caused by mutations in multiple genes and abnormalities in multiple signaling pathways, synthetic lethality for a specific tumor suppressor gene or oncogene is likely cell context-dependent. Delineation of the mechanisms underlying synthetic lethality and identification of treatment response biomarkers will be critical for the success of synthetic lethality anticancer therapy. PMID:24893124

  13. Fluctuation Analysis: The Probability Distribution of the Number of Mutants under Different Conditions

    PubMed Central

    Stewart, F. M.; Gordon, D. M.; Levin, B. R.

    1990-01-01

    In the 47 years since fluctuation analysis was introduced by Luria and Delbruck, it has been widely used to calculate mutation rates. Up to now, in spite of the importance of such calculations, the probability distribution of the number of mutants that will appear in a fluctuation experiment has been known only under the restrictive, and possibly unrealistic, assumptions: (1) that the mutation rate is exactly proportional to the growth rate and (2) that all mutants grow at a rate that is a constant multiple of the growth rate of the original cells. In this paper, we approach the distribution of the number of mutants from a new point of view that will enable researchers to calculate the distribution to be expected using assumptions that they believe to be closer to biological reality. The new idea is to classify mutations according to the number of observable mutants that derive from the mutation when the culture is selectively plated. This approach also simplifies the calculations in situations where two, or many, kinds of mutation may occur in a single culture. PMID:2307353

  14. Suppression of neuroinflammation in forebrain-specific Cdk5 conditional knockout mice by PPAR? agonist improves neuronal loss and early lethality

    PubMed Central

    2014-01-01

    Background Cyclin-dependent kinase 5 (Cdk5) is essential for brain development and function, and its deregulated expression is implicated in some of neurodegenerative diseases. We reported earlier that the forebrain-specific Cdk5 conditional knockout (cKO) mice displayed an early lethality associated with neuroinflammation, increased expression of the neuronal tissue-type plasminogen activator (tPA), and neuronal migration defects. Methods In order to suppress neuroinflammation in the cKO mice, we first treated these mice with pioglitazone, a PPAR? agonist, and analyzed its effects on neuronal loss and longevity. In a second approach, to delineate the precise role of tPA in neuroinflammation in these mice, we generated Cdk5 cKO; tPA double knockout (dKO) mice. Results We found that pioglitazone treatment significantly reduced astrogliosis, microgliosis, neuronal loss and behavioral deficit in Cdk5 cKO mice. Interestingly, the dKO mice displayed a partial reversal in astrogliosis, but they still died at early age, suggesting that the increased expression of tPA in the cKO mice does not contribute significantly to the pathological process leading to neuroinflammation, neuronal loss and early lethality. Conclusion The suppression of neuroinflammation in Cdk5 cKO mice ameliorates gliosis and neuronal loss, thus suggesting the potential beneficial effects of the PPAR? agonist pioglitazone for the treatment for neurodegenerative diseases. PMID:24495352

  15. RNA Polymerase III Defects Suppress a Conditional-Lethal Poly(a) Polymerase Mutation in Saccharomyces Cerevisiae

    PubMed Central

    Briggs, M. W.; Butler, J. S.

    1996-01-01

    We isolated spontaneous extragenic suppressors of a temperature-sensitive, lethal poly(A) polymerase mutation (pap1-1) in Saccharomyces cerevisiae that restore growth at the restrictive temperature of 30°. Three of five suppressors represent alleles of the PDS2 complementation group. The recessive pds2-1 mutation exerts dominant allele-specific suppression over pap1-1, suggesting a direct functional interaction. The suppressor restores to near normal the steady-state concentrations of various mRNAs and total poly(A) reduced by pap1-1 at 30°. Transcriptional chase experiments detect no reduction in the decay rates of mRNAs in the suppressor strain, suggesting that the restoration of steady-state message levels results from increased stable mRNA synthesis. Molecular cloning shows PDS2 to be allelic to RET1, which encodes the second-largest subunit of RNA polymerase III. We observe alterations in both the length and the steady-state amounts of RNA polymerase III transcripts in pds2-1 strains. Previously identified ret1 alleles do not suppress pap1-1, indicating that the pds2 alleles we isolated represent a specific class of RET1 mutations that suppress pap1-1. Suppression of pap1-1 by mutations in an RNA polymerase III subunit suggests a number of potentially novel interactions between these enzymes. PMID:8807289

  16. Excretion of pyruvate by mutants of Alcaligenes eutrophus , which are impaired in the accumulation of poly(?-hydroxybutyric acid) (PHB), under conditions permitting synthesis of PHB

    Microsoft Academic Search

    Alexander Steinbiichel; Hans G. Schlegel

    1989-01-01

    Mutants of Alcaligenes eutrophus, which are defective in the intracellular accumulation of poly(ß-hydroxybutyric acid), PHB, were cultivated in the presence of excess carbon source after growth had ceased due to depletion of ammonium, sulphate, phosphate, potassium, magnesium, or iron. Under these conditions all mutants excreted large amounts of pyruvate into the medium. Excretion of pyruvate occurred with lactate, gluconate or

  17. Conditional poliovirus mutants made by random deletion mutagenesis of infectious cDNA.

    PubMed Central

    Kirkegaard, K; Nelsen, B

    1990-01-01

    Small deletions were introduced into DNA plasmids bearing cDNA copies of Mahoney type 1 poliovirus RNA. The procedure used was similar to that of P. Hearing and T. Shenk (J. Mol. Biol. 167:809-822, 1983), with modifications designed to introduce only one lesion randomly into each DNA molecule. Methods to map small deletions in either large DNA or RNA molecules were employed. Two poliovirus mutants, VP1-101 and VP1-102, were selected from mutagenized populations on the basis of their host range phenotype, showing a large reduction in the relative numbers of plaques on CV1 and HeLa cells compared with wild-type virus. The deletions borne by the mutant genomes were mapped to the region encoding the amino terminus of VP1. That these lesions were responsible for the mutant phenotypes was substantiated by reintroduction of the sequenced lesions into a wild-type poliovirus cDNA by deoxyoligonucleotide-directed mutagenesis. The deletion of nucleotides encoding amino acids 8 and 9 of VP1 was responsible for the VP1-101 phenotype; the VP1-102 defect was caused by the deletion of the sequences encoding the first four amino acids of VP1. The peptide sequence at the VP1-VP3 proteolytic cleavage site was altered from glutamine-glycine to glutamine-methionine in VP1-102; this apparently did not alter the proteolytic cleavage pattern. The biochemical defects resulting from these mutations are discussed in the accompanying report. Images PMID:2152811

  18. Conditions supporting repair of potentially lethal damage cause a significant reduction of ultraviolet light-induced division delay in synchronized and plateau-phase Ehrlich ascites tumor cells

    SciTech Connect

    Iliakis, G.; Nusse, M.

    1982-09-01

    Repair of potentially lethal damage (PLD) induced by uv light in synchronized and in plateau-phase cultures of Ehrlich ascites tumor cells was studied by measuring cell survival. In particlar the influence of conditions supporting repair of PLD on growth kinetics was investigated. In synchronized G/sub 1/, S, or G/sub 2/ + M cells as well as in plateau-phase cells, uv light induced, almost exclusively, delay in the next S phase. A significant decrease of this delay was observed when the cells were incubated for 24 hr in balanced salt solution. Repair of PLD after uv irradiation was found to occur in plateau-phase cells and in cells in different phases of the cell cycle provided that after irradiation these were kept under conditions inhibiting cell multiplication (incubation in balanced salt solution or in conditioned medium). The repair time constant t/sub 50/ was significantly higher than those found for X irradiation (5-10 hr compared to 2 hr), and repair was not significantly inhibited by either 20 ..mu..g/ml cycloheximide or 2 mM caffeine in 24 hr.

  19. High-salt preadaptation of Vibrio parahaemolyticus enhances survival in response to lethal environmental stresses.

    PubMed

    Kalburge, Sai Siddarth; Whitaker, W Brian; Boyd, E Fidelma

    2014-02-01

    Adaptation to changing environmental conditions is an important strategy for survival of foodborne bacterial pathogens. Vibrio parahaemolyticus is a gram-negative seafoodborne enteric pathogen found in the marine environment both free living and associated with oysters. This pathogen is a moderate halophile, with optimal growth at 3% NaCl. Among the several stresses imposed upon enteric bacteria, acid stress is perhaps one of the most important. V. parahaemolyticus has a lysine decarboxylase system responsible for decarboxylation of lysine to the basic product cadaverine, an important acid stress response system in bacteria. Preadaptation to mild acid conditions, i.e., the acid tolerance response, enhances survival under lethal acid conditions. Because of the variety of conditions encountered by V. parahaemolyticus in the marine environment and in oyster postharvest facilities, we examined the nature of the V. parahaemolyticus acid tolerance response under high-salinity conditions. Short preadaptation to a 6% salt concentration increased survival of the wild-type strain but not that of a cadA mutant under lethal acid conditions. However, prolonged exposure to high salinity (16 h) increased survival of both the wild-type and the cadA mutant strains. This phenotype was not dependent on the stress response sigma factor RpoS. Although this preadaptation response is much more pronounced in V. parahaemolyticus, this characteristic is not limited to this species. Both Vibrio cholerae and Vibrio vulnificus also survive better under lethal acid stress conditions when preadapted to high-salinity conditions. High salt both protected the organism against acid stress and increased survival under -20°C cold stress conditions. High-salt adaptation of V. parahaemolyticus strains significantly increases survival under environmental stresses that would otherwise be lethal to these bacteria. PMID:24490918

  20. Establishment of permanent chimerism in a lactate dehydrogenase-deficient mouse mutant with hemolytic anemia

    SciTech Connect

    Datta, T.; Doermer, P.

    1987-12-01

    Pluripotent hemopoietic stem cell function was investigated in the homozygous muscle type lactate dehydrogenase (LDH-A) mutant mouse using bone marrow transplantation experiments. Hemopoietic tissues of LDH-A mutants showed a marked decreased in enzyme activity that was associated with severe hemolytic anemia. This condition proved to be transplantable into wild type mice (+/+) through total body irradiation (TBI) at a lethal dose of 8.0 Gy followed by engraftment of mutant bone marrow cells. Since the mutants are extremely radiosensitive (lethal dose50/30 4.4 Gy vs 7.3 Gy in +/+ mice), 8.0-Gy TBI followed by injection of even high numbers of normal bone marrow cells did not prevent death within 5-6 days. After a nonlethal dose of 4.0 Gy and grafting of normal bone marrow cells, a transient chimerism showing peripheral blood characteristics of the wild type was produced that returned to the mutant condition within 12 weeks. The transfusion of wild type red blood cells prior to and following 8.0-Gy TBI and reconstitution with wild type bone marrow cells prevented the early death of the mutants and permanent chimerism was achieved. The chimeras showed all hematological parameters of wild type mice, and radiosensitivity returned to normal. It is concluded that the mutant pluripotent stem cells are functionally comparable to normal stem cells, emphasizing the significance of this mouse model for studies of stem cell regulation.

  1. Functional Analysis of the Interaction between VPg-Proteinase (NIa) and RNA Polymerase (NIb) of Tobacco Etch Potyvirus, Using Conditional and Suppressor Mutants

    Microsoft Academic Search

    JOSE ´-ANTONIO DAROS; MARY C. SCHAAD; JAMES C. CARRINGTON

    1999-01-01

    The tobacco etch potyvirus (TEV) RNA-dependent RNA polymerase (NIb) has been shown to interact with the proteinase domain of the VPg-proteinase (NIa). To investigate the significance of this interaction, a Saccharomyces cerevisiae two-hybrid assay was used to isolate conditional NIa mutant proteins with tempera- ture-sensitive (ts) defects in interacting with NIb. Thirty-six unique tsNIa mutants with substitutions affecting the proteinase

  2. Animal Models For Disease--Knockout, Knockin And Conditional Mutant Mice David F. LePage and Ronald A. Conlon

    E-print Network

    almost twenty years since the first gene targeted mice were constructed (4, 5), not all parameters which mutant, animal model of disease, genetically engineered mice. 1. Introduction The generation of mutant mutations are used to define the organ, tissue or cellular autonomy of mutant effects, to circumvent

  3. Conditional Auxin Response and Differential Cytokinin Profiles in Shoot Branching Mutants1[C][W][OPEN

    PubMed Central

    Young, Naomi F.; Ferguson, Brett J.; Antoniadi, Ioanna; Bennett, Mark H.; Beveridge, Christine A.; Turnbull, Colin G.N.

    2014-01-01

    Strigolactone (SL), auxin, and cytokinin (CK) are hormones that interact to regulate shoot branching. For example, several ramosus (rms) branching mutants in pea (Pisum sativum) have SL defects, perturbed xylem CK levels, and diminished responses to auxin in shoot decapitation assays. In contrast with the last of these characteristics, we discovered that buds on isolated nodes (explants) of rms plants instead respond normally to auxin. We hypothesized that the presence or absence of attached roots would result in transcriptional and hormonal differences in buds and subtending stem tissues, and might underlie the differential auxin response. However, decapitated plants and explants both showed similar up-regulation of CK biosynthesis genes, increased CK levels, and down-regulation of auxin transport genes. Moreover, auxin application counteracted these trends, regardless of the effectiveness of auxin at inhibiting bud growth. Multivariate analysis revealed that stem transcript and CK changes were largely associated with decapitation and/or root removal and auxin response, whereas bud transcript profiles related more to SL defects. CK clustering profiles were indicative of additional zeatin-type CKs in decapitated stems being supplied by roots and thus promoting bud growth in SL-deficient genotypes even in the presence of added auxin. This difference in CK content may explain why rms buds on explants respond better to auxin than those on decapitated plants. We further conclude that rapid changes in CK status in stems are auxin dependent but largely SL independent, suggesting a model in which auxin and CK are dominant regulators of decapitation-induced branching, whereas SLs are more important in intact plants. PMID:24904042

  4. Conditional tradeoffs between aging and organismal performance of Indy long-lived mutant flies

    E-print Network

    Marden, James

    , and metabolism (1, 12). A well documented environmental perturbation, caloric restriction, also affects aging fecundity, suggesting that a tradeoff between longevity and this aspect of performance is conditional, i that pose tradeoffs between longevity and fitness early in life. Reductions in the ability to be active

  5. Assessing the essentiality of the decaprenyl-phospho-d-arabinofuranose pathway in Mycobacterium tuberculosis using conditional mutants.

    PubMed

    Kolly, Gaëlle S; Boldrin, Francesca; Sala, Claudia; Dhar, Neeraj; Hartkoorn, Ruben C; Ventura, Marcello; Serafini, Agnese; McKinney, John D; Manganelli, Riccardo; Cole, Stewart T

    2014-04-01

    In Mycobacterium tuberculosis the decaprenyl-phospho-d-arabinofuranose (DPA) pathway is a validated target for the drugs ethambutol and benzothiazinones. To identify other potential drug targets in the pathway, we generated conditional knock-down mutants of each gene involved using the TET-PIP OFF system. dprE1, dprE2, ubiA, prsA, rv2361c, tkt and rpiB were confirmed to be essential under non-permissive conditions, whereas rv3807c was not required for survival. In the most vulnerable group, DprE1-depleted cells died faster in vitro and intracellularly than those lacking UbiA and PrsA. Downregulation of DprE1 and UbiA resulted in similar phenotypes, namely swelling of the bacteria, cell wall damage and lysis as observed at the single cell level, by real time microscopy and electron microscopy. By contrast, depletion of PrsA led to cell elongation and implosion, which was suggestive of a more pleiotropic effect. Drug sensitivity assays with known DPA-inhibitors supported the use of conditional knock-down strains for target-based whole-cell screens. Together, our work provides strong evidence for the vulnerability of all but one of the enzymes in the DPA pathway and generates valuable tools for the identification of lead compounds targeting the different biosynthetic steps. PrsA, phosphoribosyl-pyrophosphate synthetase, appears to be a particularly attractive new target for drug discovery. PMID:24517327

  6. Conditional mouse mutants highlight mechanisms of corticotropin-releasing hormone effects on stress-coping behavior

    Microsoft Academic Search

    A Lu; M A Steiner; N Whittle; A M Vogl; S M Walser; M Ableitner; D Refojo; M Ekker; J L Rubenstein; G K Stalla; N Singewald; F Holsboer; C T Wotjak; W Wurst; J M Deussing

    2008-01-01

    Hypersecretion of central corticotropin-releasing hormone (CRH) has been implicated in the pathophysiology of affective disorders. Both, basic and clinical studies suggested that disrupting CRH signaling through CRH type 1 receptors (CRH-R1) can ameliorate stress-related clinical conditions. To study the effects of CRH-R1 blockade upon CRH-elicited behavioral and neurochemical changes we created different mouse lines overexpressing CRH in distinct spatially restricted

  7. Lethal mutagenesis failure may augment viral adaptation.

    PubMed

    Paff, Matthew L; Stolte, Steven P; Bull, James J

    2014-01-01

    Lethal mutagenesis, the attempt to extinguish a population by elevating its mutation rate, has been endorsed in the virology literature as a promising approach for treating viral infections. In support of the concept, in vitro studies have forced viral extinction with high doses of mutagenic drugs. However, the one known mutagenic drug used on patients commonly fails to cure infections, and in vitro studies typically find a wide range of mutagenic conditions permissive for viral growth. A key question becomes how subsequent evolution is affected if the viral population is mutated but avoids extinction--Is viral adaptation augmented rather than suppressed? Here we consider the evolution of highly mutated populations surviving mutagenesis, using the DNA phage T7. In assays using inhibitory hosts, whenever resistance mutants were observed, the mutagenized populations exhibited higher frequencies, but some inhibitors blocked plaque formation by even the mutagenized stock. Second, outgrowth of previously mutagenized populations led to rapid and potentially complete fitness recovery but polymorphism was slow to decay, and mutations exhibited inconsistent patterns of change. Third, the combination of population bottlenecks with mutagenesis did cause fitness declines, revealing a vulnerability that was not apparent from mutagenesis of large populations. The results show that a population surviving high mutagenesis may exhibit enhanced adaptation in some environments and experience little negative fitness consequences in many others. PMID:24092771

  8. Lethal Mutagenesis Failure May Augment Viral Adaptation

    PubMed Central

    Paff, Matthew L.; Stolte, Steven P.; Bull, James J.

    2014-01-01

    Lethal mutagenesis, the attempt to extinguish a population by elevating its mutation rate, has been endorsed in the virology literature as a promising approach for treating viral infections. In support of the concept, in vitro studies have forced viral extinction with high doses of mutagenic drugs. However, the one known mutagenic drug used on patients commonly fails to cure infections, and in vitro studies typically find a wide range of mutagenic conditions permissive for viral growth. A key question becomes how subsequent evolution is affected if the viral population is mutated but avoids extinction—Is viral adaptation augmented rather than suppressed? Here we consider the evolution of highly mutated populations surviving mutagenesis, using the DNA phage T7. In assays using inhibitory hosts, whenever resistance mutants were observed, the mutagenized populations exhibited higher frequencies, but some inhibitors blocked plaque formation by even the mutagenized stock. Second, outgrowth of previously mutagenized populations led to rapid and potentially complete fitness recovery but polymorphism was slow to decay, and mutations exhibited inconsistent patterns of change. Third, the combination of population bottlenecks with mutagenesis did cause fitness declines, revealing a vulnerability that was not apparent from mutagenesis of large populations. The results show that a population surviving high mutagenesis may exhibit enhanced adaptation in some environments and experience little negative fitness consequences in many others. PMID:24092771

  9. A temperature-sensitive calmodulin mutant loses viability during mitosis

    PubMed Central

    1992-01-01

    Although rare, a recessive temperature-sensitive calmodulin mutant has been isolated in Saccharomyces cerevisiae. The mutant carries two mutations in CMD1, isoleucine 100 is changed to asparagine and glutamic acid 104 is changed to valine. Neither mutation alone conferred temperature sensitivity. A single mutation that allowed production of an intact but defective protein was not identified. At the nonpermissive temperature, the temperature-sensitive mutant displayed multiple defects. Bud formation and growth was delayed, but this defect was not responsible for the temperature-sensitive lethality. Cells synchronized in G1 progressed through the cell cycle and retained viability until the movement of the nucleus to the neck between the mother cell and the large bud. After nuclear movement, less than 5% of the cells survived the first mitosis and could form colonies when returned to permissive conditions. The duplicated DNA was dispersed along the spindle, extending from mother to daughter cell. Cells synchronized in G2/M lost viability immediately upon the shift to the nonpermissive temperature. At a semipermissive temperature, the mutant showed approximately a 10-fold increase in the rate of chromosome loss compared to a wild-type strain. The mitotic phenotype is very similar to yeast mutants that are defective in chromosome disjunction. The mutant also showed defects in cytokinesis. PMID:1639846

  10. A Survey of New Temperature-Sensitive, Embryonic-Lethal Mutations in C. elegans: 24 Alleles of Thirteen Genes

    PubMed Central

    O'Rourke, Sean M.; Garner, Aleena R.; Hamill, Danielle R.; Osterberg, Valerie R.; Lyczak, Rebecca; Madison, Erin E.; Nguyen, Michael H.; Sandberg, Nathan A.; Sedghi, Noushin; Willis, John H.; Yochem, John; Johnson, Eric A.; Bowerman, Bruce

    2011-01-01

    To study essential maternal gene requirements in the early C. elegans embryo, we have screened for temperature-sensitive, embryonic lethal mutations in an effort to bypass essential zygotic requirements for such genes during larval and adult germline development. With conditional alleles, multiple essential requirements can be examined by shifting at different times from the permissive temperature of 15°C to the restrictive temperature of 26°C. Here we describe 24 conditional mutations that affect 13 different loci and report the identity of the gene mutations responsible for the conditional lethality in 22 of the mutants. All but four are mis-sense mutations, with two mutations affecting splice sites, another creating an in-frame deletion, and one creating a premature stop codon. Almost all of the mis-sense mutations affect residues conserved in orthologs, and thus may be useful for engineering conditional mutations in other organisms. We find that 62% of the mutants display additional phenotypes when shifted to the restrictive temperature as L1 larvae, in addition to causing embryonic lethality after L4 upshifts. Remarkably, we also found that 13 out of the 24 mutations appear to be fast-acting, making them particularly useful for careful dissection of multiple essential requirements. Our findings highlight the value of C. elegans for identifying useful temperature-sensitive mutations in essential genes, and provide new insights into the requirements for some of the affected loci. PMID:21390299

  11. Strategy for enhanced transgenic strain development for embryonic conditionnal lethality in Anastrepha suspensa

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Here the first reproductive sterility system for the tephritid pest, Anastrepha suspensa, is presented, based on lethality primarily in embryos heterozygous for a lethal conditional transgene combination. The tetracycline-suppressible system uses the cellularization-specific A. suspensa serendipity...

  12. Impact of acid adaptation on attachment of Listeria monocytogenes to stainless steel during long-term incubation under low or moderate temperature conditions and on subsequent recalcitrance of attached cells to lethal acid treatments.

    PubMed

    Giaouris, Efstathios; Chorianopoulos, Nikos; Nychas, George-John

    2014-02-01

    This study aimed to evaluate the possible impact of acid adaptation of Listeria monocytogenes cells on their attachment to stainless steel (SS) during long-term incubation under either low or moderate temperature conditions and on the subsequent recalcitrance of attached cells to lethal acid treatments. Initially, nonadapted or acid-adapted stationary phase L. monocytogenes cells were used to inoculate (ca. 10? CFU/ml) brain-heart infusion (BHI) broth in test tubes containing vertically placed SS coupons. Incubation was carried out at either 5 or 30 °C for up to 15 days, under static conditions. On the 5th, 10th and 15th days of incubation, attached cells were subjected to lethal acid treatments by exposing them, for either 6 or 60 min, to pH 2, adjusted with either hydrochloric or lactic acid. Following the acid treatments, remaining viable cells were detached (through strong vortexing with glass beads) and enumerated by agar plating, and also indirectly quantified by conductance measurements via their metabolic activity. Results obtained from both quantification techniques, employed here in parallel, revealed that although the numbers of attached cells for nonadapted and acid-adapted ones were similar, the latter were found to present significantly (p<0.05) increased recalcitrance to all the acid treatments for both incubation temperatures and all sampling days. In addition and regardless of acid adaptation, when long (60 min) acid treatments were applied, conductance measurements revealed that the weak organic lactic acid exhibited significantly (p<0.05) stronger antilisterial activity compared to the strong inorganic hydrochloric acid (at the same pH value of 2). To conclude, present results show that acid adaptation of L. monocytogenes cells during their planktonic growth is conserved even after 15 days of incubation under both low and moderate temperature conditions, and results in the increased recalcitrance of their sessile population to otherwise lethal acid treatments. This "stress hardening" should be severely taken into account when acidic decontamination interventions are used to kill attached to equipment surfaces cells of this important pathogenic bacterium. PMID:24296256

  13. Mice Lacking Ras-GRF1 Show Contextual Fear Conditioning but not Spatial Memory Impairments: Convergent Evidence from Two Independently Generated Mouse Mutant Lines.

    PubMed

    d'Isa, Raffaele; Clapcote, Steven J; Voikar, Vootele; Wolfer, David P; Giese, Karl Peter; Brambilla, Riccardo; Fasano, Stefania

    2011-01-01

    Ras-GRF1 is a neuronal specific guanine exchange factor that, once activated by both ionotropic and metabotropic neurotransmitter receptors, can stimulate Ras proteins, leading to long-term phosphorylation of downstream signaling. The two available reports on the behavior of two independently generated Ras-GRF1 deficient mouse lines provide contrasting evidence on the role of Ras-GRF1 in spatial memory and contextual fear conditioning. These discrepancies may be due to the distinct alterations introduced in the mouse genome by gene targeting in the two lines that could differentially affect expression of nearby genes located in the imprinted region containing the Ras-grf1 locus. In order to determine the real contribution of Ras-GRF1 to spatial memory we compared in Morris Water Maze learning Brambilla's mice with a third mouse line (GENA53) in which a non-sense mutation was introduced in the Ras-GRF1 coding region without additional changes in the genome and we found that memory in this task is normal. Also, we measured both contextual and cued fear conditioning, which were previously reported to be affected in Brambilla's mice, and we confirmed that contextual learning but not cued conditioning is impaired in both mouse lines. In addition, we also tested both lines for the first time in conditioned place aversion in the Intellicage, an ecological and remotely controlled behavioral test, and we observed normal learning. Finally, based on previous reports of other mutant lines suggesting that Ras-GRF1 may control body weight, we also measured this non-cognitive phenotype and we confirmed that both Ras-GRF1 deficient mutants are smaller than their control littermates. In conclusion, we demonstrate that Ras-GRF1 has no unique role in spatial memory while its function in contextual fear conditioning is likely to be due not only to its involvement in amygdala functions but possibly to some distinct hippocampal connections specific to contextual learning. PMID:22164138

  14. Electroshock weapons can be lethal!

    NASA Astrophysics Data System (ADS)

    Lundquist, Marjorie

    2008-03-01

    Electroshock weapons (EWs)-stun guns, tasers, riot shields-are electroconductive devices designed to safely incapacitate healthy men neuromuscularly, so they are called nonlethal or less-lethal. EW firms seeking large nonmilitary markets targeted law enforcement and corrections personnel, who began using EWs in prisons/jails and on public patrol in 1980 in the USA. This shifted the EW-shocked population from healthy soldiers to a heterogeneous mix of both sexes, ages 6-92, in a wide variety of health conditions! An EW operates by disrupting normal physiological processes, producing transient effects in healthy people. But if a person's health is sufficiently compromised, the margin of safety can be lost, resulting in death or permanent health problems. 325 people have died after EW shock since 1980. Did the EW cause these deaths? Evidence indicates that EWs do play a causal role in most such deaths. EWs can be lethal for people in diabetic shock^1 (hypoglycemia), which may be why Robert Dziekanski-a Polish immigrant to Canada-died so quickly after he was tasered at Vancouver Airport: not having eaten for over 10 hours, he likely was severely hypoglycemic. The EW death rate in North America is 30 times higher than need be, because EW users have not been properly trained to use EWs on a heterogeneous population safely! ^1J. Clinical Engineering 30(3):111(2005).

  15. Serum Amyloid A Protects Murine Macrophages from Lethal Toxin-Mediated Death1

    PubMed Central

    Rose, Kira; Long, Paul; Shankar, Malini; Ballard, Jimmy D.; Webb, Carol F.

    2011-01-01

    Lethal toxin, a key virulence factor produced by Bacillus anthracis, induces cell death, in part by disrupting numerous signaling pathways, in mouse macrophages. However, exposure to sublethal doses of lethal toxin allows some cells to survive. Because these pro-survival signaling events occur within a few hours after exposure to sublethal doses, we hypothesized that acute phase proteins might influence macrophage survival. Our data show that serum amyloid A (SAA) is produced in response to lethal toxin treatment. Moreover, pre-treatment of macrophages with exogenous SAA protected macrophages from lethal toxin-mediated death. Exogenous SAA activated the p38 mitogen activated protein kinase (MAP) kinase pathway, while lethal toxin mutants incapable of p38 activation were incapable of causing cell death. Chemical inhibition of the p38 activation pathway abrogated the protective effects of SAA. These data show that SAA affords protection against lethal toxin in mouse macrophages and link this response to the p38 pathway. PMID:22082566

  16. Dynamics of Mitochondrial RNA-Binding Protein Complex in Trypanosoma brucei and Its Petite Mutant under Optimized Immobilization Conditions

    PubMed Central

    Huang, Zhenqiu; Kaltenbrunner, Sabine; Šimková, Eva; Stan?k, David

    2014-01-01

    There are a variety of complex metabolic processes ongoing simultaneously in the single, large mitochondrion of Trypanosoma brucei. Understanding the organellar environment and dynamics of mitochondrial proteins requires quantitative measurement in vivo. In this study, we have validated a method for immobilizing both procyclic stage (PS) and bloodstream stage (BS) T. brucei brucei with a high level of cell viability over several hours and verified its suitability for undertaking fluorescence recovery after photobleaching (FRAP), with mitochondrion-targeted yellow fluorescent protein (YFP). Next, we used this method for comparative analysis of the translational diffusion of mitochondrial RNA-binding protein 1 (MRP1) in the BS and in T. b. evansi. The latter flagellate is like petite mutant Saccharomyces cerevisiae because it lacks organelle-encoded nucleic acids. FRAP measurement of YFP-tagged MRP1 in both cell lines illuminated from a new perspective how the absence or presence of RNA affects proteins involved in mitochondrial RNA metabolism. This work represents the first attempt to examine this process in live trypanosomes. PMID:25063375

  17. Physiology and proteome responses of two contrasting rice mutants and their wild type parent under salt stress conditions at the vegetative stage.

    PubMed

    Ghaffari, Akram; Gharechahi, Javad; Nakhoda, Babak; Salekdeh, Ghasem Hosseini

    2014-01-01

    Salinity is one of the major environmental limiting factors that affects growth and productivity of rice (Oryza sativa L.) worldwide. Rice is among the most sensitive crops to salinity, especially at early vegetative stages. In order to get a better understanding of molecular pathways affected in rice mutants showing contrasting responses to salinity, we exploited the power of 2-DE based proteomics to explore the proteome changes associated with salt stress response. Our physiological observations showed that standard evaluation system (SES) scores, Na+ and K+ concentrations in shoots and Na+/K+ ratio were significantly different in contrasting mutants under salt stress condition. Proteomics analysis showed that, out of 854 protein spots which were reproducibly detected, 67 protein spots showed significant responses to salt stress. The tandem mass spectrometry analysis of these significantly differentially accumulated proteins resulted in identification of 34 unique proteins. These proteins are involved in various molecular processes including defense to oxidative stresses, metabolisms, photosynthesis, protein synthesis and processing, signal transduction. Several of the identified proteins were emerged as key participants in salt stress tolerance. The possible implication of salt responsive proteins in plant adaptation to salt stress is discussed. PMID:24094368

  18. PDGFRA-mutant syndrome.

    PubMed

    Ricci, Riccardo; Martini, Maurizio; Cenci, Tonia; Carbone, Arnaldo; Lanza, Paola; Biondi, Alberto; Rindi, Guido; Cassano, Alessandra; Larghi, Alberto; Persiani, Roberto; Larocca, Luigi M

    2015-07-01

    Germline PDGFRA mutations cause multiple heterogeneous gastrointestinal mesenchymal tumors. In its familial form this disease, which was formerly termed intestinal neurofibromatosis/neurofibromatosis 3b (INF/NF3b), has been included among familial gastrointestinal stromal tumors (GISTs) because of its genotype, described when GIST was the only known PDGFRA-mutant gastrointestinal tumor. Shortly afterwards, however, inflammatory fibroid polyps also revealed PDGFRA mutations. Subsequently, gastrointestinal CD34+ 'fibrous tumors' of uncertain classification were described in a germline PDGFRA-mutant context. Our aim was to characterize the syndrome produced by germline PDGFRA mutations and establish diagnostic criteria and management strategies for this hitherto puzzling disease. We studied a kindred displaying multiple gastrointestinal mesenchymal tumors, comparing it with published families/individuals with possible analogous conditions. We identified a novel inherited PDGFRA mutation (P653L), constituting the third reported example of familial PDGFRA mutation. In adult mutants we detected inflammatory fibroid polyps, gastric GISTs and gastrointestinal fibrous tumors of uncertain nosology. We demonstrate that the syndrome formerly defined as INF/NF3b (exemplified by the family reported herein) is simplistically considered a form of familial GIST, because inflammatory fibroid polyps often prevail. Fibrous tumors appear variants of inflammatory fibroid polyps. 'INF/NF3b' and 'familial GIST' are misleading terms which we propose changing to 'PDGFRA-mutant syndrome'. In this condition, unlike KIT-dependent familial GIST syndromes, if present, GISTs are stomach-restricted and diffuse Cajal cell hyperplasia is not observed. This restriction of GISTs to the stomach in PDGFRA-mutant syndrome: (i) focuses oncological concern on gastric masses, as inflammatory fibroid polyps are benign; (ii) supports a selective role of gastric environment for PDGFRA mutations to elicit GISTs, justifying the known predilection for stomach of sporadic PDGFRA-mutant GISTs. An awareness that inflammatory fibroid polyps, relatively common among gastrointestinal mesenchymal tumors, may be the prevailing tumor in PDGFRA-mutant syndrome could eventually reveal an unsuspected prevalence of this condition. PMID:25975287

  19. Physiological and biochemical responses of fruit exocarp of tomato (Lycopersicon esculentum Mill.) mutants to natural photo-oxidative conditions.

    PubMed

    Torres, Carolina A; Andrews, Preston K; Davies, Neal M

    2006-01-01

    Photo-oxidative stress was imposed under natural solar radiation on exposed and shaded sections of detached fruit of immature green tomato (Lycopersicon esculentum Miller = Solanum lycopersicum L.) mutants (anthocyanin absent, beta-carotene, Delta, and high pigment-1) and their nearly isogenic parents ('Ailsa Craig' and 'Rutgers'). After 5 h exposure to high solar irradiance, either with or without ultraviolet (UV) radiation, surface colour changes, pigment composition, photosynthetic efficiency, antioxidant metabolites and enzyme activities, and selected flavonoids and antioxidant proteins in exocarp tissue were evaluated. The imposed photo-oxidative stress reproduced the symptoms observed on attached fruit. Both high temperature and solar irradiance caused fruit surface discoloration with faster degradation of chlorophyll (Chl) than carotenoids (Car), leading to an increase in the Car/Chl ratio. Surface bleaching was mostly caused by visible light, whereas elevated temperatures were mostly responsible for the inactivation of photosynthesis, measured as decreased F(v)/F(m). Ascorbate, glutathione, and total soluble protein concentrations decreased in the exocarp as the duration of exposure increased. Specific activities of superoxide dismutase, ascorbate peroxidase, dehydroascorbate reductase, monodehydroascorbate reductase (MDHAR), glutathione reductase (GR), and catalase increased with exposure, suggesting that these proteins were conserved during the imposed stress. GR protein expression remained stable during the imposed stress, whereas, MDHAR protein expression increased. Quercetin and kaempferol concentrations increased rapidly upon exposure, but not to UV radiation, suggesting rapid photo-protection in response to visible light; however, naringenin synthesis was not induced. The apparent increased tolerance of hp-1 fruit is discussed. PMID:16698820

  20. Tasers – Less than Lethal!

    PubMed Central

    Sharma, Abiram; Theivacumar, Nada S; Souka, Hesham M

    2009-01-01

    We report a case of potentially lethal injury associated with the use of Taser. A 42-year-old man was stopped by police for potential detention. He held a large carving knife over his epigasrium threatening to stab himself.With a view to achieving immobilisation, a Taser gun was used. On activation of the Taser, the subject suffered a 7-cm wide and 10-cm deep stab injury to the upper abdomen. In this case, activation of the Taser resulted in the contraction of skeletal muscles, flexors more intensely than extensors, resulting in the stab injury. PMID:19416583

  1. A genetic screen for temperature-sensitive cell-division mutants of Caenorhabditis elegans.

    PubMed Central

    O'Connell, K F; Leys, C M; White, J G

    1998-01-01

    A novel screen to isolate conditional cell-division mutants in Caenorhabditis elegans has been developed. The screen is based on the phenotypes associated with existing cell-division mutations: some disrupt postembryonic divisions and affect formation of the gonad and ventral nerve cord-resulting in sterile, uncoordinated animals-while others affect embryonic divisions and result in lethality. We obtained 19 conditional mutants that displayed these phenotypes when shifted to the restrictive temperature at the appropriate developmental stage. Eighteen of these mutations have been mapped; 17 proved to be single alleles of newly identified genes, while 1 proved to be an allele of a previously identified gene. Genetic tests on the embryonic lethal phenotypes indicated that for 13 genes, embryogenesis required maternal expression, while for 6, zygotic expression could suffice. In all cases, maternal expression of wild-type activity was found to be largely sufficient for embryogenesis. Cytological analysis revealed that 10 mutants possessed embryonic cell-division defects, including failure to properly segregate DNA, failure to assemble a mitotic spindle, late cytokinesis defects, prolonged cell cycles, and improperly oriented mitotic spindles. We conclude that this approach can be used to identify mutations that affect various aspects of the cell-division cycle. PMID:9649522

  2. Mesophyll conductance decreases in the wild type but not in an ABA-deficient mutant (aba1) of Nicotiana plumbaginifolia under drought conditions.

    PubMed

    Mizokami, Yusuke; Noguchi, Ko; Kojima, Mikiko; Sakakibara, Hitoshi; Terashima, Ichiro

    2015-03-01

    Under drought conditions, leaf photosynthesis is limited by the supply of CO2 . Drought induces production of abscisic acid (ABA), and ABA decreases stomatal conductance (gs ). Previous papers reported that the drought stress also causes the decrease in mesophyll conductance (gm ). However, the relationships between ABA content and gm are unclear. We investigated the responses of gm to the leaf ABA content [(ABA)L ] using an ABA-deficient mutant, aba1, and the wild type (WT) of Nicotiana plumbaginifolia. We also measured leaf water potential (?L ) because leaf hydraulics may be related to gm . Under drought conditions, gm decreased with the increase in (ABA)L in WT, whereas both (ABA)L and gm were unchanged by the drought treatment in aba1. Exogenously applied ABA decreased gm in both WT and aba1 in a dose-dependent manner. ?L in WT was decreased by the drought treatment to -0.7?MPa, whereas ?L in aba1 was around -0.8?MPa even under the well-watered conditions and unchanged by the drought treatment. From these results, we conclude that the increase in (ABA)L is crucial for the decrease in gm under drought conditions. We discuss possible relationships between the decrease in gm and changes in the leaf hydraulics. PMID:24995523

  3. Alterations in peptidoglycan chemical composition associated with rod-to-sphere transition in a conditional mutant of Klebsiella pneumoniae.

    PubMed Central

    Fontana, R; Canepari, P; Satta, G

    1979-01-01

    Klebsiella pneumoniae Mir M7 is a spontaneous parentless morphology mutant which grows as cocci at pH 7 and as rods at pH 5.8. This strain has been characterized as defective in lateral wall formation (at pH7). Data suggest that the cell wall is mainly made up of poles of the rods (G. Satta, R. Fontana, P. Canepari, and G. Botta, J. Bacteriol. 137:727--734, 1979). In this work the isolation and the biochemical properties of the peptidoglycan of both Mir M7 rods and cocci and a nonconditional rod-shaped Mir M7 revertant (strain Mir A12) are described. The peptidoglycan of Mir M7 (both rods and cocci) and Mir A12 strains carried covalently bound proteins which could be easily removed by pronase treatment in Mir M7 rods and Mir A12 cells, but not in Mir M7 round cells. However, when the sodium dodecyl sulfate-insoluble residues of Mir M7 cocci were pretreated with ethylenediaminetetraacetic acid (EDTA), pronase digestion removed the covalently bound proteins, and pure peptidoglycan was obtained. EDTA treatment of the rigid layer of Mir M7 cocci removed amounts of Mg2+ and Ca2+, which were 10- and 50-fold higher, respectively, than the amount liberated from the rigid layer of Mir M7 rods and Mir A12 cells. Amino acid composition was qualitatively similar in both strains, but Mir M7 cocci contained a higher amount of alanine and glucosamine. Mir M7 cocci contained approximately 50% less peptidoglycan than rods. Under electron microscopy, the rigid layer of the Mir M7 rods and Mir A12 cells appeared to be rod-shaped and their shape remained unchanged after EDTA and pronase treatment. On the contrary, the Mir M7 cocci rigid layer appeared to be round, and after EDTA treatment it collapsed and lost any definite morphology. In spite of these alterations, the peptidoglycan of Mir M7 cocci still appeared able to determine the shape of the cell and protect it from osmotic shock and mechanical damages. The accumluation of divalent cations appeared necessary for the peptidoglycan to acquire sufficient rigidity for shape determination and cell protection. We concluded that the coccal shape in Mir M7 cells is not due to loss of cell wall rigidity but is a consequence of the formation of a round peptidoglycan molecule. The possibility that the alterations found in the Mir M7 cocci rigid layer may reflect natural differences in the biochemical composition of the septa and lateral wall of normally shaped bacteria is discussed. Images PMID:113382

  4. Mice Lacking Ras-GRF1 Show Contextual Fear Conditioning but not Spatial Memory Impairments: Convergent Evidence from Two Independently Generated Mouse Mutant Lines

    PubMed Central

    d’Isa, Raffaele; Clapcote, Steven J.; Voikar, Vootele; Wolfer, David P.; Giese, Karl Peter; Brambilla, Riccardo; Fasano, Stefania

    2011-01-01

    Ras-GRF1 is a neuronal specific guanine exchange factor that, once activated by both ionotropic and metabotropic neurotransmitter receptors, can stimulate Ras proteins, leading to long-term phosphorylation of downstream signaling. The two available reports on the behavior of two independently generated Ras-GRF1 deficient mouse lines provide contrasting evidence on the role of Ras-GRF1 in spatial memory and contextual fear conditioning. These discrepancies may be due to the distinct alterations introduced in the mouse genome by gene targeting in the two lines that could differentially affect expression of nearby genes located in the imprinted region containing the Ras-grf1 locus. In order to determine the real contribution of Ras-GRF1 to spatial memory we compared in Morris Water Maze learning Brambilla’s mice with a third mouse line (GENA53) in which a non-sense mutation was introduced in the Ras-GRF1 coding region without additional changes in the genome and we found that memory in this task is normal. Also, we measured both contextual and cued fear conditioning, which were previously reported to be affected in Brambilla’s mice, and we confirmed that contextual learning but not cued conditioning is impaired in both mouse lines. In addition, we also tested both lines for the first time in conditioned place aversion in the Intellicage, an ecological and remotely controlled behavioral test, and we observed normal learning. Finally, based on previous reports of other mutant lines suggesting that Ras-GRF1 may control body weight, we also measured this non-cognitive phenotype and we confirmed that both Ras-GRF1 deficient mutants are smaller than their control littermates. In conclusion, we demonstrate that Ras-GRF1 has no unique role in spatial memory while its function in contextual fear conditioning is likely to be due not only to its involvement in amygdala functions but possibly to some distinct hippocampal connections specific to contextual learning. PMID:22164138

  5. The effects of body weight, temperature, salinity, pH, light intensity and feeding condition on lethal DO levels of whiteleg shrimp, Litopenaeus vannamei (Boone, 1931)

    Microsoft Academic Search

    Peidong Zhang; Xiumei Zhang; Jian Li; Guoqiang Huang

    2006-01-01

    Tolerance of whiteleg shrimp Litopenaeus vannamei exposed to different temperatures (14.5, 21.5, 24.8, 27.8, 30.8, and 35.0 °C), salinities (9, 15, 26, 35, and 40‰), pH (3.3, 6.5, 7.7, 8.1, and 9.2), and light intensities (strong 2100 lx and weak 60 lx) at various body weights (3.0, 3.7, 4.3, 5.7, 7.8, 9.0, 9.5, 10.7, 11.9, and 13.3 g) and feeding conditions (fed

  6. Lethality test system

    SciTech Connect

    Parsons, W.M.; Sims, J.R.; Parker, J.V.

    1986-01-01

    The Lethality Test System (LTS), presently under construction at Los Alamos, is an electromagnetic launcher facility designed to perform impact experiments at velocities up to 15 km/s. The launcher is a 25 mm round bore, plasma armature railgun extending 22 m in length. Preinjection is accomplished with a two-stage gas gun capable of 7 km/s. The railgun power supply utilizes traction motors, vacuum interrupters, and pulse transformers. An assembly of 28 traction motors, equipped with flywheels, stores approximately 80 MJ at 92% of full speed and energizes the primary windings of three pulse transformers at a current of 50 kA. At peak current an array of vacuum interrupters disconnects the transformer primary windings and forces the current to flow in the secondary windings. The secondary windings are connected to the railgun, and by staging the vacuum interrupter openings, a 1 MA to 1.3 MA ramped current waveform will be delivered to the railgun.

  7. Lethal and sublethal effects of cypermethrin to Hypsiboas pulchellus tadpoles

    Microsoft Academic Search

    M. Gabriela Agostini; Guillermo S. Natale; Alicia E. Ronco

    2010-01-01

    The study of the effects of the insecticide cypermethrin (CY) technical grade and its Sherpa® commercial formulation on Hypsiboas pulchellus tadpoles assessing lethality, behavior, growth, and abnormalities under standardized laboratory conditions is reported. Observed\\u000a behaviors were identified and categorized by means of a ranking system according to the loss of mobility. Results of acute\\u000a lethal effects indicate higher potency for

  8. Generalized lethality criteria for beam weapon systems

    NASA Astrophysics Data System (ADS)

    Tsai, J.

    The lethality criteria which define the interaciton between the directed energy systems and the targets have been derived. For high energy laser systems, the lethality criteria are defined in terms of a lethal fluence. For neutral particle beam systems, the lathality criteria can be specified either as lethal charge fluence or as lethal dose. Derivations are all based on an assumed circular profile in the intensity distribution along the radial direction. Three different methods to calculate the lethality criteria are introduced. Lethality criteria and dwell time requirements have been deduced. A relationship between the different lethality concepts has been formulated.

  9. Protein sorting in Saccharomyces cerevisiae: isolation of mutants defective in the delivery and processing of multiple vacuolar hydrolases.

    PubMed Central

    Robinson, J S; Klionsky, D J; Banta, L M; Emr, S D

    1988-01-01

    Using a selection for spontaneous mutants that mislocalize a vacuolar carboxypeptidase Y (CPY)-invertase fusion protein to the cell surface, we identified vacuolar protein targeting (vpt) mutants in 25 new vpt complementation groups. Additional alleles in each of the eight previously identified vpt complementation groups (vpt1 through vpt8) were also obtained. Representative alleles from each of the 33 vpt complementation groups (vpt1 through vpt33) were shown to exhibit defects in the sorting and processing of several native vacuolar proteins, including the soluble hydrolases CPY, proteinase A, and proteinase B. Of the 33 complementation groups, 19 were found to contain mutant alleles that led to extreme defects. In these mutants, CPY accumulated in its Golgi complex-modified precursor form which was secreted by the mutant cells. Normal protein secretion appeared to be unaffected in the vpt mutants. The lack of significant leakage of cytosolic markers from the vpt mutant cells indicated that the vacuolar protein-sorting defects associated with these mutants do not result from cell lysis. In addition, the observation that the precursor rather than the mature forms of CPY, proteinase A, proteinase B were secreted from the vpt mutants was consistent with the fact that mislocalization occurred at a stage after Golgi complex-specific modification, but before final vacuolar sorting of these enzymes. Vacuolar membrane protein sorting appeared to be unaffected in the majority of the vpt mutants. However, a subset of the vpt mutants (vpt11, vpt16, vpt18, and vpt33) was found to exhibit defects in the sorting of a vacuolar membrane marker enzyme, alpha-mannosidase. Up to 50% of the alpha-mannosidase enzyme activity was found to be mislocalized to the cell surface in these vpt mutants. Seven of the vpt complementation groups (vpt3, vpt11, vpt15, vpt16, vpt18, vpt29, and vpt33) contained alleles that led to a conditional lethal phenotype; the mutants were temperature sensitive for vegetative cell growth. This temperature-sensitive phenotype has been shown to be recessive and to cosegregate with the vacuolar protein-sorting defect in each case. Tetrad analysis showed that vpt3 mapped to the right arm of chromosome XV and that vpt15 mapped to the right arm of chromosome II. Intercrosses with other mutants that exhibited defects in vacuolar protein sorting or function (vpl, sec, pep, and end mutants) revealed several overlaps among these different sets of genes. Together, these data indicate that more than 50 gene products are involved, directly or indirectly, in the process of vacuolar protein sorting. Images PMID:3062374

  10. DNA repair and synthetic lethality

    PubMed Central

    Guo, Gong-she; Zhang, Feng-mei; Gao, Rui-jie; Delsite, Robert; Feng, Zhi-hui; Powell, Simon N

    2011-01-01

    Tumors often have DNA repair defects, suggesting additional inhibition of other DNA repair pathways in tumors may lead to synthetic lethality. Accumulating data demonstrate that DNA repair-defective tumors, in particular homologous recombination (HR), are highly sensitive to DNA-damaging agents. Thus, HR-defective tumors exhibit potential vulnerability to the synthetic lethality approach, which may lead to new therapeutic strategies. It is well known that poly (adenosine diphosphate (ADP)-ribose) polymerase (PARP) inhibitors show the synthetically lethal effect in tumors defective in BRCA1 or BRCA2 genes encoded proteins that are required for efficient HR. In this review, we summarize the strategies of targeting DNA repair pathways and other DNA metabolic functions to cause synthetic lethality in HR-defective tumor cells. PMID:22010575

  11. Structural Basis for a Lethal Mutation in U6 RNA†,‡

    PubMed Central

    Sashital, Dipali G.; Allmann, Anne M.; Van Doren, Steven R.; Butcher, Samuel E.

    2011-01-01

    U6 RNA is essential for nuclear pre-mRNA splicing and has been implicated directly in catalysis of intron removal. The U80G mutation at the essential magnesium binding site of the U6 3? intramolecular stem–loop region (ISL) is lethal in yeast. To further understand the structure and function of the U6 ISL, we have investigated the structural basis for the lethal U80G mutation by NMR and optical spectroscopy. The NMR structure reveals that the U80G mutation causes a structural rearrangement within the ISL resulting in the formation of a new Watson–Crick base pair (C67·G80), and disrupts a protonated C67·A79 wobble pair that forms in the wild-type structure. Despite the structural change, the accessibility of the metal binding site is unperturbed, and cadmium titration produces similar phosphorus chemical shift changes for both the U80G mutant and wild-type RNAs. The thermodynamic stability of the U80G mutant is significantly increased (??Gfold = ?3.6 ± 1.9 kcal/mol), consistent with formation of the Watson–Crick pair. Our structural and thermodynamic data, in combination with previous genetic data, suggest that the lethal basis for the U80G mutation is stem–loop hyperstabilization. This hyperstabilization may prevent the U6 ISL melting and rearrangement necessary for association with U4. PMID:12578359

  12. Potential lethal and non-lethal effects of predators on dispersal of spider mites.

    PubMed

    Otsuki, Hatsune; Yano, Shuichi

    2014-11-01

    Predators can affect prey dispersal lethally by direct consumption or non-lethally by making prey hesitate to disperse. These lethal and non-lethal effects are detectable only in systems where prey can disperse between multiple patches. However, most studies have drawn their conclusions concerning the ability of predatory mites to suppress spider mites based on observations of their interactions on a single patch or on heavily infested host plants where spider mites could hardly disperse toward intact patches. In these systems, specialist predatory mites that penetrate protective webs produced by spider mites quickly suppress the spider mites, whereas generalist predators that cannot penetrate the webs were ineffective. By using a connected patch system, we revealed that a generalist ant, Pristomyrmex punctatus Mayr (Hymenoptera: Formicidae), effectively prevented dispersal of spider mites, Tetranychus kanzawai Kishida (Acari: Tetranychidae), by directly consuming dispersing individuals. We also revealed that a generalist predatory mite, Euseius sojaensis Ehara (Acari: Phytoseiidae), prevented between-patch dispersal of T. kanzawai by making them hesitate to disperse. In contrast, a specialist phytoseiid predatory mite, Neoseiulus womersleyi Schicha, allowed spider mites to escape an initial patch, increasing the number of colonized patches within the system. Our results suggest that ants and generalist predatory mites can effectively suppress Tetranychus species under some conditions, and should receive more attention as agents for conservation biological control in agroecosystems. PMID:24867061

  13. Starch mutants of Chlamydomonas

    SciTech Connect

    Berry-Lowe, S.L.; Schmidt, G.W. (Univ. of Georgia, Athens (USA))

    1990-05-01

    Wild type Chlamydomonas accumulates starch and triglycerides when grown under nitrogen limiting conditions. Toward elucidation of the mechanisms for control of starch biosynthesis, we isolated mutants impaired int he accumulation of storage carbohydrates. Chlamydomonas reinhardtii (strain ya-12) was mutagenized by UV irradiation and colonies were screened by iodine staining after growth in darkness. Mutants, denoted ais for altered in iodine staining, have been characterized by electron microscopy and assays for starch synthease, ADPG-pyrophosphorylase, phosphoglucose isomerase (PGI), phosphoglucomutase and fructose 1,6-bisphosphatase, and amylase activities. Transcript analysis of wild type and mutant RNAs with PGI, ADPG-pyrophosphorylase, and waxy probes have also been carried out. No deficiencies of any of these components have been detected. Furthermore, long-term cultures of ya-12 and ais-1d in nitrogen-limited chemostats have been studied; starch also does not accumulate in ais-1d under these conditions. Thus, the lesion affects an essential factor of unknown identity that is required for starch synthesis.

  14. Proton Gradient Regulation 5-Mediated Cyclic Electron Flow under ATP- or Redox-Limited Conditions: A Study of ?ATPase pgr5 and ?rbcL pgr5 Mutants in the Green Alga Chlamydomonas reinhardtii1[C][W

    PubMed Central

    Johnson, Xenie; Steinbeck, Janina; Dent, Rachel M.; Takahashi, Hiroko; Richaud, Pierre; Ozawa, Shin-Ichiro; Houille-Vernes, Laura; Petroutsos, Dimitris; Rappaport, Fabrice; Grossman, Arthur R.; Niyogi, Krishna K.; Hippler, Michael; Alric, Jean

    2014-01-01

    The Chlamydomonas reinhardtii proton gradient regulation5 (Crpgr5) mutant shows phenotypic and functional traits similar to mutants in the Arabidopsis (Arabidopsis thaliana) ortholog, Atpgr5, providing strong evidence for conservation of PGR5-mediated cyclic electron flow (CEF). Comparing the Crpgr5 mutant with the wild type, we discriminate two pathways for CEF and determine their maximum electron flow rates. The PGR5/proton gradient regulation-like1 (PGRL1) ferredoxin (Fd) pathway, involved in recycling excess reductant to increase ATP synthesis, may be controlled by extreme photosystem I acceptor side limitation or ATP depletion. Here, we show that PGR5/PGRL1-Fd CEF functions in accordance with an ATP/redox control model. In the absence of Rubisco and PGR5, a sustained electron flow is maintained with molecular oxygen instead of carbon dioxide serving as the terminal electron acceptor. When photosynthetic control is decreased, compensatory alternative pathways can take the full load of linear electron flow. In the case of the ATP synthase pgr5 double mutant, a decrease in photosensitivity is observed compared with the single ATPase-less mutant that we assign to a decreased proton motive force. Altogether, our results suggest that PGR5/PGRL1-Fd CEF is most required under conditions when Fd becomes overreduced and photosystem I is subjected to photoinhibition. CEF is not a valve; it only recycles electrons, but in doing so, it generates a proton motive force that controls the rate of photosynthesis. The conditions where the PGR5 pathway is most required may vary in photosynthetic organisms like C. reinhardtii from anoxia to high light to limitations imposed at the level of carbon dioxide fixation. PMID:24623849

  15. Comparative proteomics of a tor inducible Aspergillus fumigatus mutant reveals involvement of the Tor kinase in iron regulation.

    PubMed

    Baldin, Clara; Valiante, Vito; Krüger, Thomas; Schafferer, Lukas; Haas, Hubertus; Kniemeyer, Olaf; Brakhage, Axel A

    2015-07-01

    The Tor (target of rapamycin) kinase is one of the major regulatory nodes in eukaryotes. Here, we analyzed the Tor kinase in Aspergillus fumigatus, which is the most important airborne fungal pathogen of humans. Because deletion of the single tor gene was apparently lethal, we generated a conditional lethal tor mutant by replacing the endogenous tor gene by the inducible xylp-tor gene cassette. By both 2DE and gel-free LC-MS/MS, we found that Tor controls a variety of proteins involved in nutrient sensing, stress response, cell cycle progression, protein biosynthesis and degradation, but also processes in mitochondria, such as respiration and ornithine metabolism, which is required for siderophore formation. qRT-PCR analyses indicated that mRNA levels of ornithine biosynthesis genes were increased under iron limitation. When tor was repressed, iron regulation was lost. In a deletion mutant of the iron regulator HapX also carrying the xylp-tor cassette, the regulation upon iron deprivation was similar to that of the single tor inducible mutant strain. In line, hapX expression was significantly reduced when tor was repressed. Thus, Tor acts either upstream of HapX or independently of HapX as a repressor of the ornithine biosynthesis genes and thereby regulates the production of siderophores. PMID:25728394

  16. The Genetic Analysis of Snf: A Drosophila Sex Determination Gene Required for Activation of Sex-Lethal in Both the Germline and the Soma

    PubMed Central

    Salz, H. K.

    1992-01-01

    Our analysis demonstrates that snf is a positive regulator of Sex-lethal in both the germline and the soma. In the germline, unregulated expression of Sex-lethal can bypass the requirement for snf(+) gene function, implying that snf is required for Sex-lethal activity in the germline. This conclusion is supported by the finding that the Sex-lethal transcription pattern is abnormal in a snf mutant background. In the soma, activation of Sex-lethal appears to be sensitive to snf gene dosage only when the probability of Sex-lethal activation has been otherwise reduced. We also show that the activity of one of the constitutive Sex-lethal alleles (Sxl(M1)) is sensitive to snf gene dosage, demonstrating that, in spite of its constitutive behavior in some assays, Sxl(M1) is still subject to some regulation. In spite of snf's role in the somatic activation of Sex-lethal, no lethal alleles of snf were isolated in a screen of ~25,000 chromosomes. The observation that the existing snf mutations present a lethal phenotype only in certain genetic backgrounds suggests that snf is required, but is not essential, for the activation of Sex-lethal in the soma. In contrast, snf does appear to be essential for activation of Sex-lethal in the germline, as evidenced by its female-sterile phenotype. PMID:1551576

  17. Characterization of cottonseed nutrients composition in near isogenic cotton (Gossypium hirsutum L.) mutant lines for fuzzless seed trait under well-watered and water stress conditions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cotton mutant near isogenic lines (NILs) for fuzzless seed trait has been used to investigate cell biology, genetic, and molecular processes of fiber initiation, development, fiber yield and quality. However, there is no information available on the effect of fuzzless seed trait on cottonseed nutrie...

  18. Arenavirus extinction through lethal mutagenesis

    Microsoft Academic Search

    Juan Carlos de la Torre

    2005-01-01

    Viral hemorrhagic fevers represent serious human public health problems causing devastating and often lethal disease. Several hemorrhagic fevers are caused by arenaviruses including Lassa fever virus (LFV) and the South American viral hemorrhagic fevers (SAHF). In recent years, increased air travel between Africa and other areas has led to the importation of LFV into the US, Europe, Japan, and Canada.

  19. Phosphate Homeostasis in Conditions of Phosphate Proficiency and Limitation in the Wild Type and the phoP Mutant of Streptomyces lividans

    PubMed Central

    Prigent, Magali; Holland, Ian Barry; Virolle, Marie-Joelle

    2015-01-01

    Phosphate, as a constituent of the high energy molecules, ATP/GTP and polyphosphate, plays a crucial role in most of the metabolic processes of living organisms. Therefore, the adaptation to low Pi availability is a major challenge for bacteria. In Streptomyces, this adaptation is tightly controlled by the two component PhoR/PhoP system. In this study, the free intracellular Pi, ATP, ADP and polyP content of the wild type and the phoP mutant strain of S. lividans TK24 were analyzed at discrete time points throughout growth in Pi replete and limited media. PolyP length and content was shown to be directly related to the Pi content of the growth medium. In Pi repletion, ATP and high molecular weight (HMW) polyP contents were higher in the phoP mutant than in the WT strain. This supports the recently proposed repressive effect of PhoP on oxidative phosphorylation. High oxidative phosphorylation activity might also have a direct or indirect positive impact on HMW polyP synthesis. In Pi sufficiency as in Pi limitation, the degradation of these polymers was shown to be clearly delayed in the phoP mutant, indicating PhoP dependent expression of the enzymes involved in this degradation. The efficient storage of Pi as polyphosphate and/or its inefficient degradation in Pi in the phoP mutant resulted in low levels of free Pi and ATP that are likely to be, at least in part, responsible for the very poor growth of this mutant in Pi limitation. Furthermore, short polyP was shown to be present outside the cell, tightly bound to the mycelium via electrostatic interactions involving divalent cations. Less short polyP was found to be associated with the mycelium of the phoP mutant than with that of the WT strain, indicating that generation and externalization of these short polyP molecules was directly or indirectly dependent on PhoP. PMID:25978423

  20. Introduction to Lethal School Violence

    Microsoft Academic Search

    Jeffrey A. Daniels; Mary C. Bradley

    \\u000a In this chapter, we offer an introduction to the topic of the book, lethal school violence (LSV). We begin with an introduction\\u000a to and definition of LSV, and then highlight five different situations that often result in fatalities (i.e., suicide, rampage\\u000a shootings, gang-related deaths, domestic murder\\/suicide that occurs on campus, and barricaded captive events). We then turn\\u000a our attention to

  1. Cytokinesis-Defective Mutants of Arabidopsis1

    PubMed Central

    Söllner, Rosi; Glässer, Gerti; Wanner, Gehard; Somerville, Chris R.; Jürgens, Gerd; Assaad, Farhah F.

    2002-01-01

    We have identified mutations in six previously uncharacterized genes of Arabidopsis, named club, bublina, massue, rod, bloated, and bims, that are required for cytokinesis. The mutants are seedling lethal, have morphological abnormalities, and are characterized by cell wall stubs, gapped walls, and multinucleate cells. In these and other respects, the new mutants are phenotypically similar to knolle, keule, hinkel, and pleiade mutants. The mutants display a gradient of stomatal phenotypes, correlating roughly with the severity of their cytokinesis defect. Similarly, the extent to which the different mutant lines were capable of growing in tissue culture correlated well with the severity of the cytokinesis defect. Phenotypic analysis of the novel and previously characterized loci indicated that the secondary consequences of a primary defect in cytokinesis include anomalies in body organization, organ number, and cellular differentiation, as well as organ fusions and perturbations of the nuclear cycle. Two of the 10 loci are required for both cytokinesis and root hair morphogenesis. The results have implications for the identification of novel cytokinesis genes and highlight the mechanistic similarity between cytokinesis and root hair morphogenesis, two processes that result in a rapid deposition of new cell walls via polarized secretion. PMID:12068111

  2. Ethical language and decision-making for prenatally diagnosed lethal malformations.

    PubMed

    Wilkinson, Dominic; de Crespigny, Lachlan; Xafis, Vicki

    2014-10-01

    In clinical practice, and in the medical literature, severe congenital malformations such as trisomy 18, anencephaly, and renal agenesis are frequently referred to as 'lethal' or as 'incompatible with life'. However, there is no agreement about a definition of lethal malformations, nor which conditions should be included in this category. Review of outcomes for malformations commonly designated 'lethal' reveals that prolonged survival is possible, even if rare. This article analyses the concept of lethal malformations and compares it to the problematic concept of 'futility'. We recommend avoiding the term 'lethal' and suggest that counseling should focus on salient prognostic features instead. For conditions with a high chance of early death or profound impairment in survivors despite treatment, perinatal and neonatal palliative care would be ethical. However, active obstetric and neonatal management, if desired, may also sometimes be appropriate. PMID:25200733

  3. Ethical language and decision-making for prenatally diagnosed lethal malformations

    PubMed Central

    Wilkinson, Dominic; de Crespigny, Lachlan; Xafis, Vicki

    2014-01-01

    Summary In clinical practice, and in the medical literature, severe congenital malformations such as trisomy 18, anencephaly, and renal agenesis are frequently referred to as ‘lethal’ or as ‘incompatible with life’. However, there is no agreement about a definition of lethal malformations, nor which conditions should be included in this category. Review of outcomes for malformations commonly designated ‘lethal’ reveals that prolonged survival is possible, even if rare. This article analyses the concept of lethal malformations and compares it to the problematic concept of ‘futility’. We recommend avoiding the term ‘lethal’ and suggest that counseling should focus on salient prognostic features instead. For conditions with a high chance of early death or profound impairment in survivors despite treatment, perinatal and neonatal palliative care would be ethical. However, active obstetric and neonatal management, if desired, may also sometimes be appropriate. PMID:25200733

  4. Autosomal recessive lethal mutations in two mutator stocks of Drosophila ananassae.

    PubMed

    Matsuda, M

    1991-12-01

    The frequency of recessive lethals in the 2nd chromosome was examined in two mutator stocks of Drosophila ananassae, ca and ca; px. They are characterized respectively by possessing an extrachromosomal clastogenic mutator in males, and by the retrotransposon "tom", which induces Om mutability only in females. The frequencies of recessive lethal mutations in the 2nd chromosome among progenies from males and females of the ca; px stock are 0.35 and 0.34 percent, respectively. Similarity of these frequencies indicates that tom does not induce recessive lethals in females. In contrast to the ca; px stock, the frequency of recessive lethals in males of the ca mutator stock was estimated to be 1.54 percent for the 2nd chromosome. No visible mutants except Minutes were recovered. Some recessive lethals derived from ca stock males were associated with chromosomal rearrangements. Being consistent with its high rate of Minute mutation it was demonstrated that the ca clastogenic mutator also induced recessive lethals. PMID:1814375

  5. The Maternally Expressed WRKY Transcription Factor TTG2 Controls Lethality in Interploidy Crosses of Arabidopsis

    PubMed Central

    Dilkes, Brian P; Spielman, Melissa; Weizbauer, Renate; Watson, Brian; Burkart-Waco, Diana; Scott, Rod J; Comai, Luca

    2008-01-01

    The molecular mechanisms underlying lethality of F1 hybrids between diverged parents are one target of speciation research. Crosses between diploid and tetraploid individuals of the same genotype can result in F1 lethality, and this dosage-sensitive incompatibility plays a role in polyploid speciation. We have identified variation in F1 lethality in interploidy crosses of Arabidopsis thaliana and determined the genetic architecture of the maternally expressed variation via QTL mapping. A single large-effect QTL, DR. STRANGELOVE 1 (DSL1), was identified as well as two QTL with epistatic relationships to DSL1. DSL1 affects the rate of postzygotic lethality via expression in the maternal sporophyte. Fine mapping placed DSL1 in an interval encoding the maternal effect transcription factor TTG2. Maternal parents carrying loss-of-function mutations in TTG2 suppressed the F1 lethality caused by paternal excess interploidy crosses. The frequency of cellularization in the endosperm was similarly affected by both natural variation and ttg2 loss-of-function mutants. The simple genetic basis of the natural variation and effects of single-gene mutations suggests that F1 lethality in polyploids could evolve rapidly. Furthermore, the role of the sporophytically active TTG2 gene in interploidy crosses indicates that the developmental programming of the mother regulates the viability of interploidy hybrid offspring. PMID:19071961

  6. Acute and sub-lethal response to mercury in Arctic and boreal calanoid copepods.

    PubMed

    Overjordet, Ida Beathe; Altin, Dag; Berg, Torunn; Jenssen, Bjørn Munro; Gabrielsen, Geir Wing; Hansen, Bjørn Henrik

    2014-10-01

    Acute lethal toxicity, expressed as LC50 values, is a widely used parameter in risk assessment of chemicals, and has been proposed as a tool to assess differences in species sensitivities to chemicals between climatic regions. Arctic Calanus glacialis and boreal Calanus finmarchicus were exposed to mercury (Hg(2+)) under natural environmental conditions including sea temperatures of 2° and 10°C, respectively. Acute lethal toxicity (96 h LC50) and sub-lethal molecular response (GST expression; in this article gene expression is used as a synonym of gene transcription, although it is acknowledged that gene expression is also regulated, e.g., at translation and protein stability level) were studied. The acute lethal toxicity was monitored for 96 h using seven different Hg concentrations. The sub-lethal experiment was set up on the basis of nominal LC50 values for each species using concentrations equivalent to 50, 5 and 0.5% of their 96 h LC50 value. No significant differences were found in acute lethal toxicity between the two species. The sub-lethal molecular response revealed large differences both in response time and the fold induction of GST, where the Arctic species responded both faster and with higher mRNA levels of GST after 48 h exposure. Under the natural exposure conditions applied in the present study, the Arctic species C. glacialis may potentially be more susceptible to mercury exposure on the sub-lethal level. PMID:25036619

  7. Characterization of the proteasome ß2 subunit gene and its mutant allele in the tephritid fruit fly pest, Anastrepha suspensa

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Conditional lethal release (CLR) is a proposed variation of the sterile insect technique (SIT) for the biological control of pest insects that would result from the release of transgenic insects carrying dominant conditional lethal genes. After mating with pest insects in the field, lethal gene exp...

  8. Early events of lethal action by tobramycin in Pseudomonas aeruginosa

    SciTech Connect

    Raulston, J.E.

    1988-01-01

    The immediate activities of the aminoglycoside antibiotic, tobramycin, were investigated in Pseudomonas aeruginosa PAO1. The influence of carbon growth substate and the antibiotic exposure environment in the magnitude of activity were examined. Lethality by 8 {mu}g/ml tobramycin occurred rapidly (1 to 3 minutes). The release of specific cellular components into the supernatant was associated with lethality. This material was initially detected as an increase in UV-absorbance. Magnesium in the reaction mixture provided protection against lethality and leakage, but did not reverse lethal damage after a 3 minute tobramycin treatment. Also, uptake of {sup 3}H-tobramycin was reduced in the presence of magnesium. Cells grown with glucose as a carbon source were more susceptible than organic acid grown cells as was the rapidity and amount of cell damage. Analyses of the leakage material revealed a 2-fold increase of protein in the supernatant after a 1-3 minute treatment which paralleled lethality. A prominent 29 kDa protein was observed by SDS-PAGE in the released material, which has been identified as the periplasmic enzyme, {beta}-lactamase. The immediate activities of tobramycin did not involve (i) release of overall cell protein, (ii) massive loss of total pool amino acids, (iii) cell lysis, (iv) inhibition of proline uptake, (v) release of lipopolysaccharide, or (vi) leakage of ATP. Electron microscopy showed no apparent damage after a 3 minute exposure. 40% inhibition of protein synthesis had occurred by 3 minutes of exposure, while release of UV-absorbing material and lethality were detectable after only 1 minute. Resistant cystic fibrosis isolates of P. aeruginosa did not leak under the same experimental conditions, but one of two susceptible strains examined did show increased UV-absorbance following treatment.

  9. Tasers--less than lethal!

    PubMed

    Sharma, Abiram; Theivacumar, Nada S; Souka, Hesham M

    2009-05-01

    We report a case of potentially lethal injury associated with the use of Taser. A 42-year-old man was stopped by police for potential detention. He held a large carving knife over his epigasrium threatening to stab himself. With a view to achieving immobilisation, a Taser gun was used. On activation of the Taser, the subject suffered a 7-cm wide and 10-cm deep stab injury to the upper abdomen. In this case, activation of the Taser resulted in the contraction of skeletal muscles, flexors more intensely than extensors, resulting in the stab injury. PMID:19416583

  10. Isolation and characterization of a low phytic acid rice mutant reveals a mutation in the rice orthologue of maize mik.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Using a forward genetics approach, we isolated two independent low phytic acid (lpa) rice mutants, N15-186 and N15-375. Both mutants are caused by single gene, recessive non-lethal mutations which result in approximately 75% (N15-186) and 43% (N15-375) reductions in seed phytic acid (inositol hexaki...

  11. A Synthetic Lethal Screen Identifies a Role for Lin-44/Wnt in C. elegans Embryogenesis

    E-print Network

    Hartin, Samantha N.; Hudson, Martin L.; Yingling, Curtis; Ackley, Brian D.

    2015-05-04

    in ptp-3B exhibit a low level of embryonic (Emb) and larval lethality (Lva) as well as Variable-abnormal body morphology defects (Vab) (Fig 2 and Table 1). How- ever, most ptp-3 LOF mutants are superficially normal in appearance. Similarly, sdn-1 mutants...002 Table 1. Lethality by genotype analyses. Genotype a Brood Size Avg (St Dev) b Phenotype c Avg (St Dev) N d Emb Lva Vab WT wild type 247.6 (35.6) 0.5 (0.6) 1.0 (0.7) 0.0 (0.0) 98.5 (0.9) 1238 ptp-3(mu245) 82.0 (51.6) 2.1 (1.7) 8.4 (4.7) 2.2 (2.8) 87...

  12. DNA helicase gene interaction network defined using synthetic lethality analyzed by microarray

    Microsoft Academic Search

    Siew Loon Ooi; Daniel D Shoemaker; Jef D Boeke

    2003-01-01

    We describe a new synthetic lethality analysis by microarray (SLAM) technique that uses ?4,600 Saccharomyces cerevisiae haploid deletion mutants with molecular 'bar codes' (TAGs). We used SGS1 and SRS2, two 3??5? DNA helicase genes, as 'queries' to identify their redundant and unique biological functions. We introduced these 'query mutations' into a haploid deletion pool by integrative transformation to disrupt the

  13. Deletion of the chloroplast-localized AtTerC gene product in Arabidopsis thaliana leads to loss of the thylakoid membrane and to seedling lethality.

    PubMed

    Kwon, Kwang-Chul; Cho, Myeon Haeng

    2008-08-01

    Early seedling development in plants depends on the biogenesis of chloroplasts from proplastids, accompanied by the formation of thylakoid membranes. An Arabidopsis thaliana gene, AtTerC, whose gene product shares sequence similarity with bacterial tellurite resistance C (TerC), is shown to be involved in a critical step required for the normal organization of prothylakoids and transition into mature thylakoid stacks. The AtTerC gene encodes an integral membrane protein, which contains eight putative transmembrane helices, localized in the thylakoid of the chloroplast, as shown by localization of an AtTerC-GFP fusion product in protoplasts and by immunoblot analysis of subfractions of chloroplasts. T-DNA insertional mutation of AtTerC resulted in a pigment-deficient and seedling-lethal phenotype under normal light conditions. Transmission electron microscopic analysis revealed that mutant etioplasts had normal prolamellar bodies (PLBs), although the prothylakoids had ring-like shapes surrounding the PLBs. In addition, the ultrastructures of mutant chloroplasts lacked thylakoids, did not have grana stacks, and showed numerous globular structures of varying sizes. Also, the accumulation of thylakoid membrane proteins was severely defective in this mutant. These results suggest that the AtTerC protein plays a crucial role in prothylakoid membrane biogenesis and thylakoid formation in early chloroplast development. PMID:18429937

  14. Intronic T-DNA Insertion Renders Arabidopsis opr3 a Conditional Jasmonic Acid-Producing Mutant1[C][W][OA

    PubMed Central

    Chehab, E. Wassim; Kim, Se; Savchenko, Tatyana; Kliebenstein, Daniel; Dehesh, Katayoon; Braam, Janet

    2011-01-01

    Jasmonic acid and its derived metabolites (JAs) orchestrate plant defense against insects and fungi. 12-Oxo-phytodienoic acid (OPDA), a JA precursor, has also been implicated in plant defense. We sought to define JAs and OPDA functions through comparative defense susceptibility characteristics of three Arabidopsis (Arabidopsis thaliana) genotypes: aos, lacking JAs and OPDA; opda reductase3 (opr3), deficient in JA production but can accumulate OPDA; and transgenics that overexpress OPR3. opr3, like aos, is susceptible to cabbage loopers (Trichoplusia ni) but, relative to aos, opr3 has enhanced resistance to a necrotrophic fungus. Gas chromatography-mass spectrometry reveals that opr3 produces OPDA but no detectable JAs following wounding and looper infestation; unexpectedly, substantial levels of JAs accumulate in opr3 upon fungal infection. Full-length OPR3 transcripts accumulate in fungal-infected opr3, potentially through splicing of the T-DNA containing intron. Fungal resistance correlates with levels of JAs not OPDA; therefore, opr3 resistance to some pests is likely due to JA accumulation, and signaling activities ascribed to OPDA should be reassessed because opr3 can produce JAs. Together these data (1) reinforce the primary role JAs play in plant defense against insects and necrotrophic fungi, (2) argue for a reassessment of signaling activities ascribed to OPDA, and (3) provide evidence that mutants with intron insertions can retain gene function. PMID:21487047

  15. Lethality and Entropy of Protein Interaction Networks

    Microsoft Academic Search

    Thomas Manke; Lloyd Demetrius; Martin Vingron

    Abstract We characterize protein interaction networks in terms of network entropy. This approach sug- gests a ranking principle, which strongly correlates with elements of functional importance, such as lethal proteins. Our combined analysis of protein interaction networks and functional proflles in single cellular yeast and mulit-cellular worm shows that proteins with large contribution to net- work entropy are preferentially lethal.

  16. Crisis Intervention with Highly Lethal Suicidal People.

    ERIC Educational Resources Information Center

    Leenaars, Antoon A.

    1994-01-01

    Outlines model for crisis intervention with highly lethal suicidal people. Explores idea that crisis is a perception, including issues of lethality and perturbation, object relations, responsibility, weapon availability, and active versus passive response. Highlights specific problems with transference and countertransference. Suggests that there…

  17. Alcohol Consumption and Nearly Lethal Suicide Attempts.

    ERIC Educational Resources Information Center

    Powell, Kenneth E.; Kresnow, Marcie-jo; Mercy, James A.; Potter, Lloyd B.; Swann, Alan C.; Frankowski, Ralph F.; Lee, Roberta K.; Bayer, Timothy L.

    2002-01-01

    Presents a case-control study of the association between nearly lethal suicide attempts and facets of alcohol consumption; namely, drinking frequency, drinking quantity, binge drinking, alcoholism, drinking within 3 hours of suicide attempt, and age began drinking. In bivariate analyses, all measures were associated with nearly lethal suicide…

  18. Lethal photosensitization of Helicobacter species

    NASA Astrophysics Data System (ADS)

    Millson, Charles E.; Wilson, Michael; MacRobert, Alexander J.; Thurrell, Wendy; Mlkvy, Peter; Davies, Claire; Bown, Stephen G.

    1995-01-01

    Helicobacter pylori (H. pylori) is associated with a large number of gastroduodenal disorders. Clearance of the bacteria has been shown to benefit patients with duodenal ulcers, gastric ulcers, and certain rare types of gastric tumors. Broad-spectrum antibiotics are the mainstay of current treatment strategies but side-effects, poor compliance, and drug resistance limit their usefulness. We sensitized H. pylori with toluidine blue, haematoporphyrin derivative, aluminum disulphonated phthalocyanine, methylene blue or protoporphyrin IX prior to exposure to low-power laser light from either a gallium aluminum arsenide laser or a helium neon gas laser. All 5 sensitizers caused reductions of greater than 1000-fold in the number of viable bacteria. Light alone had no effect and only HpD caused a significant decrease in bacterial numbers without laser light. Next, we sensitized H. mustelae on explanted ferret gastric mucosa (ex vivo) with the same sensitizers and exposed them to light from a copper vapor pumped dye laser tuned appropriately. MB caused significant reductions in bacterial counts. Successful lethal photosensitization of Helicobacter pylori both in vitro and ex vivo raises the possibility of a local method for eradicating the bacteria, especially as the bacteria are only found in those parts of the upper gastrointestinal tract that are accessible to the endoscope.

  19. Reaming experiments for the lethality test system

    SciTech Connect

    Hooten, D.; Stanley, P.

    1988-01-01

    Various reaming techniques were tried for use on the barrel of the Lethality Test System railgun. This report covers the successes and failures of the reamers and the techniques that were tried. 5 figs.

  20. Analysis of Arabidopsis thaliana atfer4-1, atfh and atfer4-1/atfh mutants uncovers frataxin and ferritin contributions to leaf ionome homeostasis.

    PubMed

    Murgia, Irene; Vigani, Gianpiero

    2015-09-01

    Ferritins are iron-storage proteins involved in the environmental and developmental control of the free iron pool within cells. Plant ferritins are targeted to mitochondria as well as to chloroplasts. AtFer4 is the Arabidopsis thaliana ferritin isoform that can be also targeted to mitochondria. Frataxin is a mitochondrial protein whose role is essential for plants; lack of AtFH frataxin causes early embryo-lethality in Arabidopsis. Because of that, the Arabidopsis atfh KO mutant is propagated in heterozygosis. For exploring the functional interaction between frataxin and ferritin, Arabidopsis double mutant atfer4-1/atfh was isolated and its physiological parameters were measured, as well as its ionome profile, together with those of both atfer4 and atfh single mutants, in different conditions of Fe supply. Impairment of both ferritin and frataxin did not lead to any effect on mitochondrial respiration. However, ionomics revealed that the content of macro- and microelements, occurring when the nutritional Fe supply changes, were altered in the mutants analysed. These results suggest that both ferritin and frataxin can contribute to the composition of the leaf ionome and also confirm ionomics as an excellent tool for detecting alterations in the plant's physiology. PMID:26042547

  1. Oral Spore Vaccine Based on Live Attenuated Nontoxinogenic Bacillus anthracis Expressing Recombinant Mutant Protective Antigen

    Microsoft Academic Search

    R. Aloni-Grinstein; O. Gat; Z. Altboum; B. Velan; S. Cohen; A. Shafferman

    2005-01-01

    An attenuated nontoxinogenic nonencapsulated Bacillus anthracis spore vaccine expressing high levels of recombinant mutant protective antigen (PA), which upon subcutaneous immunization provided protection against a lethal B. anthracis challenge, was found to have the potential to serve also as an oral vaccine. Guinea pigs immunized per os with the recombinant spore vaccine were primed to B. anthracis vegetative antigens as

  2. Production of maternal-zygotic mutant zebrafish by germ-line replacement

    Microsoft Academic Search

    Brian Ciruna; Gilbert Weidinger; Holger Knaut; Bernard Thisse; Christine Thisse; Erez Raz; Alexander F. Schier

    2002-01-01

    We report a generally applicable strategy for transferring zygotic lethal mutations through the zebrafish germ line. By using a morpholino oligonucleotide that blocks primordial germ cell (PGC) development, we generate embryos devoid of endogenous PGCs to serve as hosts for the transplantation of germ cells derived from homozygous mutant donors. Successful transfers are identified by the localization of specifically labeled

  3. Effect of vanillic acid on COQ6 mutants identified in patients with coenzyme Q10 deficiency.

    PubMed

    Doimo, Mara; Trevisson, Eva; Airik, Rannar; Bergdoll, Marc; Santos-Ocaña, Carlos; Hildebrandt, Friedhelm; Navas, Placido; Pierrel, Fabien; Salviati, Leonardo

    2014-01-01

    Human COQ6 encodes a monooxygenase which is responsible for the C5-hydroxylation of the quinone ring of coenzyme Q (CoQ). Mutations in COQ6 cause primary CoQ deficiency, a condition responsive to oral CoQ10 supplementation. Treatment is however still problematic given the poor bioavailability of CoQ10. We employed S. cerevisiae lacking the orthologous gene to characterize the two different human COQ6 isoforms and the mutations found in patients. COQ6 isoform a can partially complement the defective yeast, while isoform b, which lacks part of the FAD-binding domain, is inactive but partially stable, and could have a regulatory/inhibitory function in CoQ10 biosynthesis. Most mutations identified in patients, including the frameshift Q461fs478X mutation, retain residual enzymatic activity, and all patients carry at least one hypomorphic allele, confirming that the complete block of CoQ biosynthesis is lethal. These mutants are also partially stable and allow the assembly of the CoQ biosynthetic complex. In fact treatment with two hydroxylated analogues of 4-hydroxybenzoic acid, namely, vanillic acid or 3-4-hydroxybenzoic acid, restored the respiratory growth of yeast ?coq6 cells expressing the mutant huCOQ6-isoa proteins. These compounds, and particularly vanillic acid, could therefore represent an interesting therapeutic option for COQ6 patients. PMID:24140869

  4. Programmed Cell Death in the Leaves of the Arabidopsis Spontaneous Necrotic Spots (sns-D) Mutant Correlates with Increased Expression of the Eukaryotic Translation Initiation Factor eIF4B2

    PubMed Central

    Gaussand, Gwénaël M. D. J.-M.; Jia, Qi; van der Graaff, Eric; Lamers, Gerda E. M.; Fransz, Paul F.; Hooykaas, Paul J. J.; de Pater, Sylvia

    2011-01-01

    From a pool of transgenic Arabidopsis (Arabidopsis thaliana) plants harboring an activator T-DNA construct, one mutant was identified that developed spontaneous necrotic spots (sns-D) on the rosette leaves under aseptic conditions. The sns-D mutation is dominant and homozygous plants are embryo lethal. The mutant produced smaller rosettes with a different number of stomata than the wild-type. DNA fragmentation in the nuclei of cells in the necrotic spots and a significant increase of caspase-3 and caspase-6 like activities in sns-D leaf extracts indicated that the sns-D mutation caused programmed cell death (PCD). The integration of the activator T-DNA caused an increase of the expression level of At1g13020, which encodes the eukaryotic translation initiation factor eIF4B2. The expression level of eIF4B2 was positively correlated with the severity of sns-D mutant phenotype. Overexpression of the eIF4B2 cDNA mimicked phenotypic traits of the sns-D mutant indicating that the sns-D mutant phenotype is indeed caused by activation tagging of eIF4B2. Thus, incorrect regulation of translation initiation may result in PCD. PMID:22639576

  5. Crystallographic studies of the Anthrax lethal toxin. Annual report

    SciTech Connect

    Frederick, C.A.

    1996-07-01

    The lethal form of Anthrax results from the inhalation of anthrax spores. Death is primarily due to the effects of the lethal toxin (Protective Antigen (PA) + Lethal Factor) from the causative agent, Bacillus anthracis. All the Anthrax vaccines currently in use or under development contain or produce PA, the major antigenic component of anthrax toxin, and there is a clear need for an improved vaccine for human use. In the previous report we described the first atomic resolution structure of PA, revealing that the molecule is composed largely of beta-sheets organized into four domains. This information can be used in the design. of recombinant PA vaccines. In this report we describe additional features of the full-length PA molecule derived from further crystallographic refinement and careful examination of the structure. We compare two crystal forms of PA grown at different pH values and discuss the functional implications. A complete definition of the function of each domain must await the crystal structure of the PA63 heptamer. We have grown crystals of the heptamer under both detergent and detergent-free conditions, and made substantial progress towards the crystal structure. The mechanism of anthrax intoxication in the light of our results is reviewed.

  6. Monofunctional alkylating agent-induced inactivation, mutagenesis and DNA degradation in an Escherichia coli mutant deficient in DNA polymerase

    Microsoft Academic Search

    G. B. Smirnov; Yu. N. Favorskaya; A. G. Skavronskaya

    1971-01-01

    The DNA polymerase deficient mutantE. coli P3478polA1 is extremely sensitive to the lethal action of N-methyl-N'-nitro-N-nitrosoguanidine (NG) and methyl-methanesulfonate (MMS). ThepolA1 mutant has an almost unaffected mutability induced by NG or MMS and shows reduced ability to propagate MMS-treated phage T7. NG and MMS induce marked breakdown of DNA and inhibit significantly DNA synthesis in thepolA1 mutant. The obtained results

  7. Effects of fuzzless cottonseed phenotype on cottonseed nutrient composition in near isogenic cotton (Gossypium hirsutum L.) mutant lines under well-watered and water stress conditions1

    PubMed Central

    Bellaloui, Nacer; Turley, Rickie B.

    2013-01-01

    There is no information available on the effect of fuzzless seed trait on cottonseed nutrient composition (minerals, N, S, protein, and oil) under drought stress. The objective of this research was to investigate the effect of the fuzzless seed trait on cottonseed nutrients using five sets of near-isogenic lines (NILs). Each set consists of two lines that share the same genetic background, but differ in seed fuzziness (fuzzy, F; fuzzless, N). The near isogenic lines will enable us to compare the effect of the trait without confounding the genotypic background effects. We hypothesized that since the fuzzless trait involved in fiber initiation development, and was reported to be involved in biochemical, molecular, and genetic processes, this trait may also alter cottonseed nutrient composition. Results showed that NIL sets accumulated different levels of minerals in seeds and leaves, and the fuzzless trait (N) in most of the lines altered seed and leaf mineral accumulations when compared with fuzzy lines (F) or the control line. For example, K, P, Mg, Cu, and Na concentrations in seeds were higher in MD N and STV N than in their equivalent MD F and STV F lines. Leaf concentrations of Ca, K, Mg, S, B, Cu, and Fe in MD N lines were higher than MD F line. Lower levels of nutrients in seeds and leaves were observed under water stress conditions, especially Ca, Mg, N, and B in seeds.Generally and with few exceptions, seed protein was higher in fuzzy lines than in fuzzless lines; however, seed oil was higher in fuzzless lines than in fuzzy lines. Our research demonstrated that fuzzless trait altered the composition and level of nutrients in seed and leaves in well watered and water stressed plants. Differences in protein and oil between fuzzy and fuzzless seeds may indicate alteration in nitrogen and carbon fixation and metabolism. The differential accumulation of seed nutrients in this germplasm could be used by cotton breeders to select for higher cottonseed quality. PMID:24416037

  8. Phenotypes of lexA mutations in Salmonella enterica: evidence for a lethal lexA null phenotype due to the Fels-2 prophage.

    PubMed

    Bunny, Kim; Liu, Jing; Roth, John

    2002-11-01

    The LexA protein of Escherichia coli represses the damage-inducible SOS regulon, which includes genes for repair of DNA. Surprisingly, lexA null mutations in Salmonella enterica are lethal even with a sulA mutation, which corrects lexA lethality in E. coli. Nine suppressors of lethality isolated in a sulA mutant of S. enterica had lost the Fels-2 prophage, and seven of these (which grew better) had also lost the Gifsy-1 and Gifsy-2 prophages. All three phage genomes included a homologue of the tum gene of coliphage 186, which encodes a LexA-repressed cI antirepressor. The tum homologue of Fels-2 was responsible for lexA lethality and had a LexA-repressed promoter. This basis of lexA lethality was unexpected because the four prophages of S. enterica LT2 are not strongly UV inducible and do not sensitize strains to UV killing. In S. enterica, lexA(Ind(-)) mutants have the same phenotypes as their E. coli counterparts. Although lexA null mutants express their error-prone DinB polymerase constitutively, they are not mutators in either S. enterica or E. coli. PMID:12399494

  9. Contribution of Lethal Toxin and Edema Toxin to the Pathogenesis of Anthrax Meningitis ?

    PubMed Central

    Ebrahimi, Celia M.; Sheen, Tamsin R.; Renken, Christian W.; Gottlieb, Roberta A.; Doran, Kelly S.

    2011-01-01

    Bacillus anthracis is a Gram-positive spore-forming bacterium that causes anthrax disease in humans and animals. Systemic infection is characterized by septicemia, toxemia, and meningitis, the main neurological complication associated with high mortality. We have shown previously that B. anthracis Sterne is capable of blood-brain barrier (BBB) penetration, establishing the classic signs of meningitis, and that infection is dependent on the expression of both major anthrax toxins, lethal toxin (LT) and edema toxin (ET). Here we further investigate the contribution of the individual toxins to BBB disruption using isogenic toxin mutants deficient in lethal factor, ?LF, and edema factor, ?EF. Acute infection with B. anthracis Sterne and the ?LF mutant resulted in disruption of human brain microvascular endothelial cell (hBMEC) monolayer integrity and tight junction protein zona occludens-1, while the result for cells infected with the ?EF mutant was similar to that for the noninfected control. A significant decrease in bacterial invasion of BBB endothelium in vitro was observed during infection with the ?LF strain, suggesting a prominent role for LT in promoting BBB interaction. Further, treatment of hBMECs with purified LT or chemicals that mimic LT action on host signaling pathways rescued the hypoinvasive phenotype of the ?LF mutant and resulted in increased bacterial uptake. We also observed that toxin expression reduced bacterial intracellular survival by inducing the bulk degradative autophagy pathway in host cells. Finally, in a murine model of anthrax meningitis, mice infected with the ?LF mutant exhibited no mortality, brain bacterial load, or evidence of meningitis compared to mice infected with the parental or ?EF strains. PMID:21518787

  10. Production of maternal-zygotic mutant zebrafish by germ-line replacement

    PubMed Central

    Ciruna, Brian; Weidinger, Gilbert; Knaut, Holger; Thisse, Bernard; Thisse, Christine; Raz, Erez; Schier, Alexander F.

    2002-01-01

    We report a generally applicable strategy for transferring zygotic lethal mutations through the zebrafish germ line. By using a morpholino oligonucleotide that blocks primordial germ cell (PGC) development, we generate embryos devoid of endogenous PGCs to serve as hosts for the transplantation of germ cells derived from homozygous mutant donors. Successful transfers are identified by the localization of specifically labeled donor PGCs to the region of the developing gonad in chimeric embryos. This strategy, which results in the complete replacement of the host germ line with donor PGCs, was validated by the generation of maternal and maternal-zygotic mutants for the miles apart locus. This germ-line replacement technique provides a powerful tool for studying the maternal effects of zygotic lethal mutations. Furthermore, the ability to generate large clutches of purely mutant embryos will greatly facilitate embryological, genetic, genomic, and biochemical studies. PMID:12397179

  11. The Action of the Notch Locus in DROSOPHILA MELANOGASTER. II. Biochemical Effects of Recessive Lethals on Mitochondrial Enzymes

    PubMed Central

    Thörig, George E. W.; Heinstra, Pieter W. H.; Scharloo, Willem

    1981-01-01

    We show that six mapped recessive lethal point mutations of the Notch locus affect mitochondrial enzyme activities: NADH oxidase, NADH dehydrogenase, succinate dehydrogenase and ?-glycerophosphate dehydrogenase. The mutant N264-40, which has the same morphological and embryological effects as the Notch8 deletion, demonstrates the same biochemical effects and dosage relations as Notch8. The other five mapped recessive lethals also affect four enzymic activities. They show specific patterns of activity that depend in several cases on the wild-type chromosome in the heterozygous females. That effect occurs with mutants located in the extreme right part of the Notch locus where some mutations, according to other authors, show temperature-sensitive expression. PMID:6804303

  12. Chemically Induced Conditional Rescue of the Reduced Epidermal Fluorescence8 Mutant of Arabidopsis Reveals Rapid Restoration of Growth and Selective Turnover of Secondary Metabolite Pools1[C][OPEN

    PubMed Central

    Kim, Jeong Im; Ciesielski, Peter N.; Donohoe, Bryon S.; Chapple, Clint; Li, Xu

    2014-01-01

    The phenylpropanoid pathway is responsible for the biosynthesis of diverse and important secondary metabolites including lignin and flavonoids. The reduced epidermal fluorescence8 (ref8) mutant of Arabidopsis (Arabidopsis thaliana), which is defective in a lignin biosynthetic enzyme p-coumaroyl shikimate 3?-hydroxylase (C3?H), exhibits severe dwarfism and sterility. To better understand the impact of perturbation of phenylpropanoid metabolism on plant growth, we generated a chemically inducible C3?H expression construct and transformed it into the ref8 mutant. Application of dexamethasone to these plants greatly alleviates the dwarfism and sterility and substantially reverses the biochemical phenotypes of ref8 plants, including the reduction of lignin content and hyperaccumulation of flavonoids and p-coumarate esters. Induction of C3?H expression at different developmental stages has distinct impacts on plant growth. Although early induction effectively restored the elongation of primary inflorescence stem, application to 7-week-old plants enabled them to produce new rosette inflorescence stems. Examination of hypocotyls of these plants revealed normal vasculature in the newly formed secondary xylem, presumably restoring water transport in the mutant. The ref8 mutant accumulates higher levels of salicylic acid than the wild type, but depletion of this compound in ref8 did not relieve the mutant’s growth defects, suggesting that the hyperaccumulation of salicylic acid is unlikely to be responsible for dwarfism in this mutant. PMID:24381065

  13. Therapeutically targeting RNA viruses via lethal mutagenesis

    PubMed Central

    Graci, Jason D; Cameron, Craig E

    2008-01-01

    RNA viruses exhibit increased mutation frequencies relative to other organisms. Recent work has attempted to exploit this unique feature by increasing the viral mutation frequency beyond an extinction threshold, an antiviral strategy known as lethal mutagenesis. A number of novel nucleoside analogs have been designed around this premise. Herein, we review the quasispecies nature of RNA viruses and survey the antiviral, biological and biochemical characteristics of mutagenic nucleoside analogs, including clinically-used ribavirin. Biological implications of modulating viral replication fidelity are discussed in the context of translating lethal mutagenesis into a clinically-useful antiviral strategy. PMID:19727424

  14. SspA Is Required for Lethal Salmonella enterica Serovar Typhimurium Infections in Calves but Is Not Essential for Diarrhea

    PubMed Central

    Tsolis, Renée M.; Adams, L. Garry; Hantman, Michael J.; Scherer, Christina A.; Kimbrough, Tyler; Kingsley, Robert A.; Ficht, Thomas A.; Miller, Samuel I.; Bäumler, Andreas J.

    2000-01-01

    Salmonella pathogenicity island 1 (SPI-1) encodes virulence determinants, which are important for enteropathogenicity in calves. To determine whether the Salmonella enterica serovar Typhimurium SPI-1 effector proteins SspA and SptP are important for enteropathogenicity, strains lacking these proteins were tested during oral infection of calves. Calves infected with a sptP mutant or its isogenic parent developed diarrhea and lethal morbidity. In contrast, calves infected with an sspA mutant developed diarrhea, which resolved within 10 days but did not result in mortality. The sspA mutant was recovered from bovine intestinal tissues at numbers similar to those obtained for its isogenic parent and caused marked intestinal lesions. Thus, the severity of pathological changes caused by serovar Typhimurium strains or their ability to cause diarrhea were not predictive of their ability to cause lethal morbidity in calves. We conclude that factors other than or in addition to bacterial colonization, intestinal lesions, or electrolyte loss contribute to lethal morbidity in calves infected with serovar Typhimurium. PMID:10816458

  15. Lethality mechanisms in Escherichia coli induced by intense sub-microsecond electrical pulses

    NASA Astrophysics Data System (ADS)

    Chalise, P. R.; Perni, S.; Shama, G.; Novac, B. M.; Smith, I. R.; Kong, M. G.

    2006-10-01

    In this letter, the authors present the inactivation kinetics of cells of Escherichia coli and its mutants following treatment with high-intensity electrical pulses of 700 and 32ns durations. Their experimental results suggest that bacterial inactivation by 700ns pulses is consistent with a mechanism of reversible electroporation, whereas inactivation by 32ns pulses may occur as a result of damage to intracellular components. They believe that their results represent a first step towards elucidating the mechanism of lethality of submicrosecond pulses of different durations in prokaryotes.

  16. Lesion mimic mutants

    PubMed Central

    Moeder, Wolfgang

    2008-01-01

    Over the last decade a substantial number of lesion mimic mutants (LMM) have been isolated and a growing number of the genes have been cloned. It is now becoming clear that these mutants are valuable tools to dissect various aspects of programmed cell death (PCD) and pathogen resistance pathways in plants. Together with other forward genetics approaches LMMs shed light on the PCD machinery in plant cells and revealed important roles for sphingolipids, Ca2+ and chloroplast-derived porphyrin-metabolites during cell death development. PMID:19513227

  17. Conditions?

    Microsoft Academic Search

    A. Christy Wyckoff; Scott E. Henke; Kurt C. VerCauteren

    Research interests in feral hogs typically involve their negative impacts on ecosystems or their potential as a disease reservoir, especially with disease transmission to domestic swine. Authors within scientific literature state that feral hogs were captured as part of their research, but usually fail to mention specific conditions in which hogs were captured. Novice researchers of feral hogs must rely

  18. Autotaxin Overexpression Causes Embryonic Lethality and Vascular Defects

    PubMed Central

    Yukiura, Hiroshi; Kano, Kuniyuki; Kise, Ryoji; Inoue, Asuka; Aoki, Junken

    2015-01-01

    Autotaxin (ATX) is a secretory protein, which converts lysophospholipids to lysophosphatidic acid (LPA), and is essential for embryonic vascular formation. ATX is abundantly detected in various biological fluids and its level is elevated in some pathophysiological conditions. However, the roles of elevated ATX levels remain to be elucidated. In this study, we generated conditional transgenic (Tg) mice overexpressing ATX and examined the effects of excess LPA signalling. We found that ATX overexpression in the embryonic period caused severe vascular defects and was lethal around E9.5. ATX was conditionally overexpressed in the neonatal period using the Cre/loxP system, which resulted in a marked increase in the plasma LPA level. This resulted in retinal vascular defects including abnormal vascular plexus and increased vascular regression. Our findings indicate that the ATX level must be carefully regulated to ensure coordinated vascular formation PMID:25992708

  19. Physiological characterization of 'stay green' mutants in durum wheat.

    PubMed

    Spano, G; Di Fonzo, N; Perrotta, C; Platani, C; Ronga, G; Lawlor, D W; Napier, J A; Shewry, P R

    2003-05-01

    Four mutants with delayed leaf senescence were selected from seed of durum wheat mutagenized with ethylmethane sulphonate. Changes in net photosynthetic rate, efficiency of photosystem II and chlorophyll concentration during the maturation and senescence of the flag leaves of both mutant and parental plants were determined under glasshouse conditions. The four mutant lines maintained photosynthetic competence for longer than the parental line and are therefore functionally 'stay green'. The mutant lines also had higher seed weights and grain yields per plant than the parental line. PMID:12709488

  20. Growth and development of maize that contains mutant tubulin genes

    SciTech Connect

    Susan M. Wick

    2004-07-23

    Mutant maize plants containing a Mu transposon disrupting one of the five beta tubulin genes of interest were followed for several generations and hybridized with each other to produce plants containing disruptions in both copies of a single gene or disruption of more than one tubulin gene. Seedlings of some of these plants were grown under chilling conditions for a few weeks. After DOE funding ended, plants have been assessed to see whether mutant are more or less tolerant to chilling. Other mutant plants will be assessed for their male and female fertility relative to non-mutant siblings or other close relatives.

  1. Crystal structure of the anthrax lethal factor

    Microsoft Academic Search

    Andrew D. Pannifer; Thiang Yian Wong; Robert Schwarzenbacher; Martin Renatus; Carlo Petosa; Jadwiga Bienkowska; D. Borden Lacy; R. John Collier; Stephen H. Leppla; Philip Hanna; Robert C. Liddington

    2001-01-01

    Lethal factor (LF) is a protein (relative molecular mass 90,000) that is critical in the pathogenesis of anthrax. It is a highly specific protease that cleaves members of the mitogen-activated protein kinase kinase (MAPKK) family near to their amino termini, leading to the inhibition of one or more signalling pathways. Here we describe the crystal structure of LF and its

  2. Non-lethal technologies—an overview

    Microsoft Academic Search

    Nick LEWER; Neil DAVISON

    hilst the focus for this issue of Disarmament Forum is on chemical and biological weapons, sight should not be lost of the spectrum of non-lethal technologies that are being deployed or under development. These technologies will have an increasing impact on war fighting, peace support operations, civil policing and prison control. It is our purpose here to briefly review the

  3. Mutant maize variety containing the glt1-1 allele

    DOEpatents

    Nelson, Oliver E. (Cross Plains, WI); Pan, David (Madison, WI)

    1994-01-01

    A maize plant has in its genome a non-mutable form of a mutant allele designated vitX-8132. The allele is located at a locus designated as glt which conditions kernels having an altered starch characteristic. Maize plants including such a mutant allele produce a starch that does not increase in viscosity on cooling, after heating.

  4. Mutant maize variety containing the glt1-1 allele

    DOEpatents

    Nelson, O.E.; Pan, D.

    1994-07-19

    A maize plant has in its genome a non-mutable form of a mutant allele designated vitX-8132. The allele is located at a locus designated as glt which conditions kernels having an altered starch characteristic. Maize plants including such a mutant allele produce a starch that does not increase in viscosity on cooling, after heating. 2 figs.

  5. Neurobehavioral Mutants Identified in an ENU Mutagenesis Project

    SciTech Connect

    Cook, Melloni N. [University of Memphis; Dunning, Jonathan P [University of Memphis; Wiley, Ronald G [Vanderbilt University and Veterans Administration, Nashville, TN; Chesler, Elissa J [ORNL; Johnson, Dabney K [ORNL; Goldowitz, Daniel [University of Tennessee Health Science Center, Memphis

    2007-01-01

    We report on a behavioral screening test battery that successfully identified several neurobehavioral mutants among a large-scale ENU-mutagenized mouse population. Large numbers of ENU mutagenized mice were screened for abnormalities in central nervous system function based on abnormal performance in a series of behavior tasks. We developed and employed a high-throughput screen of behavioral tasks to detect behavioral outliers. Twelve mutant pedigrees, representing a broad range of behavioral phenotypes, have been identified. Specifically, we have identified two open field mutants (one displaying hyper-locomotion, the other hypo-locomotion), four tail suspension mutants (all displaying increased immobility), one nociception mutant (displaying abnormal responsiveness to thermal pain), two prepulse inhibition mutants (displaying poor inhibition of the startle response), one anxiety-related mutant (displaying decreased anxiety in the light/dark test), and one learning and memory mutant (displaying reduced response to the conditioned stimulus) These findings highlight the utility of a set of behavioral tasks used in a high throughput screen to identify neurobehavioral mutants. Further analysis (i.e., behavioral and genetic mapping studies) of mutants is in progress with the ultimate goal of identification of novel genes and mouse models relevant to human disorders as well as the identification of novel therapeutic targets.

  6. Bacillus subtilis mutants deficient in the adaptive response to simple alkylating agents

    SciTech Connect

    Morohoshi, F.; Munakata, N.

    1985-03-01

    Three mutant strains exhibiting hyper-sensitivity to N-methyl-N'-nitro-N-nitrosoguanidine, but not to methyl methanesulfonate, were selected by a replica method from mutagenized spores of Bacillus subtilis. All three were totally deficient in the adaptive response to N-methyl-N'-nitro-N-nitrosoguanidine with regard to both lethality and mutagenesis. The activity to destroy O/sup 6/-methylguanine residues in the methylated DNA was not elevated in the mutant cells by the pretreatment with sublethal concentrations of N-methyl-N-nitro-N-nitrosoguanidine. This deficiency corresponded to the persistance of O/sup 6/-methylguanine residues in the DNA of both control and pretreated mutant cells challenged with the drug. The lethal and mutagenic sensitivity of the mutant strains were observed only for methyl- or ethyl-nitroso compounds that are thought to be active as inducers and are also active in O-alkylation. Except for the insensitivity to methyl methanesulfonate, the phenotypes of these mutants look very similar to those of ada mutants isolated previously in Escherichia coli.

  7. MICROBIOLOGY: Enhanced: Fighting Anthrax with a Mutant Toxin

    NSDL National Science Digital Library

    Sjur Olsnes (Institute for Cancer Research; Department of Biochemistry)

    2008-10-05

    Access to the article is free, however registration and sign-in are required: There is an urgent need to develop new therapeutics against the microbe causing anthrax, which has the potential to be used in biological warfare. In their Perspective, Olsnes and Wesche discuss a new therapeutic approach designed by Sellman and colleagues. In this approach, a mutant subunit of the toxin prevents correct assembly of wild-type subunits into a pore in the host cell membrane. In this way, lethal bacterial enzymes are prevented from translocating into the host cell.

  8. Mutant knots H. R. Morton

    E-print Network

    Morton, Hugh

    Mutant knots H. R. Morton February 25, 2013 Abstract Mutants provide pairs of knots with many of their restrictions and generalisations. 1 History Remarkably little of John Conway's published work is on knot theory

  9. Fiducial Generalized Confidence Interval for Median Lethal Dose (LD50)

    E-print Network

    Hannig, Jan

    Fiducial Generalized Confidence Interval for Median Lethal Dose (LD50) Lidong E , Jan Hannig and Hari Iyer§ July 20, 2009 Abstract Median lethal dose (LD50) is a common measure of acute toxicity lethal dose (LD50), Fiducial Generalized Confidence In- terval (FGCI), Gibbs sampling. This work

  10. Gene function prediction from congruent synthetic lethal interactions in yeast

    Microsoft Academic Search

    Ping Ye; Brian D Peyser; Xuewen Pan; Jef D Boeke; Forrest A Spencer; Joel S Bader

    2005-01-01

    We predicted gene function using synthetic lethal genetic interactions between null alleles in Saccharomyces cerevisiae. Phenotypic and protein interaction data indicate that synthetic lethal gene pairs function in parallel or compensating pathways. Congruent gene pairs, defined as sharing synthetic lethal partners, are in single pathway branches. We predicted benomyl sensitivity and nuclear migration defects using congruence; these phenotypes were uncorrelated

  11. Crystallographic studies of the Anthrax lethal toxin. Annual report

    Microsoft Academic Search

    1996-01-01

    The lethal form of Anthrax results from the inhalation of anthrax spores. Death is primarily due to the effects of the lethal toxin (Protective Antigen (PA) + Lethal Factor) from the causative agent, Bacillus anthracis. All the Anthrax vaccines currently in use or under development contain or produce PA, the major antigenic component of anthrax toxin, and there is a

  12. An Arabidopsis pex10 Null Mutant Is Embryo Lethal, Implicating Peroxisomes in an Essential Role during

    E-print Network

    functions in plants, including seed reserve mobilization, photorespiration, defense against oxidative stress during Plant Embryogenesis1 Imogen A. Sparkes, Federica Brandizzi, Stephen P. Slocombe, Mahmoud El-Shami2 , Chris Hawes, and Alison Baker* Centre for Plant Sciences, University of Leeds, Leeds LS2 9JT United

  13. Protection by alpha 1-acid glycoprotein against tumor necrosis factor- induced lethality

    PubMed Central

    1994-01-01

    We here report that alpha 1-acid glycoprotein, a typical acute phase protein, protects mice from lethal shock induced by tumor necrosis factor (TNF) or endotoxin. The protection is observed both in normal and in galactosamine-sensitized mice. Optimal desensitization requires at least 3 mg alpha 1-acid glycoprotein administered 2 h before the lethal challenge. Under these conditions, complete inhibition of all TNF-induced metabolic changes was observed: fall in body temperature, release of liver transaminases, enhanced clotting time, and mortality. The known platelet aggregation-inhibitory activity of alpha 1-acid glycoprotein provides a possible explanation for this protective capacity. PMID:7931089

  14. [The characteristics of the expression of temperature-dependent dominant lethal mutations in Drosophila melanogaster].

    PubMed

    Miasniankina, E N; Generalova, M V

    1993-01-01

    The results of a series of investigations on obtaining and analysing dominant temperature-sensitive lethals (DTS-lethals) are summarized. Using EMS, both cold- and heat sensitive mutations of this type were induced in large autosomes. The cold-sensitive mutations of chromosome 3 were revealed for the first time. The effect of genetic phone on DTS lethal penetrance and expressivity was studied. The character of expression of two mutations possessing a pleiotropic action was examined. The heat-sensitive 1(2)M90DTS mutation disturbed the structure of abdominal tergites in all imago and, besides, caused an abrupt decrease in the female reproductive period. The pattern of alterations observed in oogenesis along with the result of phenogenetic analysis suggest that this gene takes part in the genetic control over the proliferation of stem oogonial cells. The cold-sensitive 1(2)M66DCS mutation caused a number of disturbances in imago thoracic structures: inability to flight, raised up wings, extremity fracture, etc. Mutant flies showed serious disorders of indirect flight muscles both at morphological and at ultrastructural levels. It was established that this mutation was a cold-sensitive allele of Mhc gene which controls the synthesis of myosine heavy chains in drosophila. PMID:8471970

  15. Enhancement of Overgrowth by Gene Interactions in Lethal(2)giant Discs Imaginal Discs from Drosophila Melanogaster

    PubMed Central

    Buratovich, M. A.; Bryant, P. J.

    1997-01-01

    Recessive lethal mutations of the lethal(2)giant discs (l(2)gd) and lethal(2)fat (l(2)ft) loci of Drosophila melanogaster cause imaginal disc hyperplasia during a prolonged larval stage. Imaginal discs from l(2)ft l(2)gd or Gl(2)gd double homozygotes show more extensive overgrowth than in either single homozygote, and double homozygous l(2)ft l(2)gd mitotic clones in adult flies show much more overgrowth than is seen in clones homozygous for either l(2)gd or l(2)ft alone. dachsous (ds) also acts as an enhancer of l(2)gd, producing dramatically overgrown discs and causing failure to pupariate in double homozygotes. The comb gap (cg) mutation, which also interacts with ds, greatly enhances the tendency of imaginal discs from l(2)gd larvae to duplicate as they overgrow. If l(2)gd homozygotes are made heterozygous for l(2)ft, then several discs duplicate, indicating that l(2)ft acts as a dominant enhancer of l(2)gd. l(2)ft also acts as a dominant enhancer of l(2)gd, and conversely l(2)gd acts as a dominant modifier of l(2)ft. The enhancement of overgrowth caused by various mutant combinations is accompanied by changes in expression of Decapentaplegic and Wingless. These results show that tumor suppressor genes act in combination to control cell proliferation, and that tissue hyperplasia can be associated with ectopic expression of genes involved in pattern formation. PMID:9335602

  16. Enhancement of overgrowth by gene interactions in lethal(2)giant discs imaginal discs from Drosophila melanogaster.

    PubMed

    Buratovich, M A; Bryant, P J

    1997-10-01

    Recessive lethal mutations of the lethal(2)giant discs (l(2)gd) and lethal(2)fat (l(2)ft) loci of Drosophila melanogaster cause imaginal disc hyperplasia during a prolonged larval stage. Imaginal discs from l(2)ft l(2)gd or Gl(2)gd double homozygotes show more extensive overgrowth than in either single homozygote, and double homozygous l(2)ft l(2)gd mitotic clones in adult flies show much more overgrowth than is seen in clones homozygous for either l(2)gd or l(2)ft alone. dachsous (ds) also acts as an enhancer of l(2)gd, producing dramatically overgrown discs and causing failure to pupariate in double homozygotes. The comb gap (cg) mutation, which also interacts with ds, greatly enhances the tendency of imaginal discs from l(2)gd larvae to duplicate as they overgrow. If l(2)gd homozygotes are made heterozygous for l(2)ft, then several discs duplicate, indicating that l(2)ft acts an a dominant enhancer of l(2)gd. l(2)ft also acts as a dominant enhancer of l(2)gd, and conversely l(2)gd acts as a dominant modifier of l(2)ft. The enhancement of overgrowth caused by various mutant combinations is accompanied by changes in expression of Decapentaplegic and Wingless. These results show that tumor suppressor genes act in combination to control cell proliferation, and that tissue hyperplasia can be associated with ectopic expression of genes involved in pattern formation. PMID:9335602

  17. DNA helicase gene interaction network defined using synthetic lethality analyzed by microarray.

    PubMed

    Ooi, Siew Loon; Shoemaker, Daniel D; Boeke, Jef D

    2003-11-01

    We describe a new synthetic lethality analysis by microarray (SLAM) technique that uses approximately 4,600 Saccharomyces cerevisiae haploid deletion mutants with molecular 'bar codes' (TAGs). We used SGS1 and SRS2, two 3'-->5' DNA helicase genes, as 'queries' to identify their redundant and unique biological functions. We introduced these 'query mutations' into a haploid deletion pool by integrative transformation to disrupt the query gene in every cell, generating a double mutant pool. Optimization of integrative transformation efficiency was essential to the success of SLAM. Synthetic interactions defined a DNA helicase genetic network and predicted a role for SRS2 in processing damaged replication forks but, unlike SGS1, not in rDNA replication, DNA topology or lagging strand synthesis. SGS1 and SRS2 have synthetic defects with MRC1 but not RAD9, suggesting that SGS1 and SRS2 function in a parallel pathway with MRC1 to transduce the DNA replication stress signal to the general DNA damage checkpoint pathway. Both helicase genes have rad51-reversible synthetic defects with 5'-->3' DNA helicase RRM3, suggesting that RRM3 helps prevent formation of toxic recombination intermediates. SLAM detects synthetic lethality efficiently and ranks candidate genetic interactions, making it an especially useful method. PMID:14566339

  18. Lethal Mutagenesis of Foot-and-Mouth Disease Virus Involves Shifts in Sequence Space?†

    PubMed Central

    Perales, Celia; Henry, Michel; Domingo, Esteban; Wain-Hobson, Simon; Vartanian, Jean-Pierre

    2011-01-01

    Lethal mutagenesis or virus transition into error catastrophe is an antiviral strategy that aims at extinguishing a virus by increasing the viral mutation rates during replication. The molecular basis of lethal mutagenesis is largely unknown. Previous studies showed that a critical substitution in the foot-and-mouth disease virus (FMDV) polymerase was sufficient to allow the virus to escape extinction through modulation of the transition types induced by the purine nucleoside analogue ribavirin. This substitution was not detected in mutant spectra of FMDV populations that had not replicated in the presence of ribavirin, using standard molecular cloning and nucleotide sequencing. Here we selectively amplify and analyze low-melting-temperature cDNA duplexes copied from FMDV genome populations passaged in the absence or presence of ribovirin Hypermutated genomes with high frequencies of A and U were present in both ribavirin -treated and untreated populations, but the major effect of ribavirin mutagenesis was to accelerate the occurrence of AU-rich mutant clouds during the early replication rounds of the virus. The standard FMDV quasispecies passaged in the absence of ribavirin included the salient transition-modulating, ribavirin resistance mutation, whose frequency increased in populations treated with ribavirin. Thus, even nonmutagenized FMDV quasispecies include a deep, mutationally biased portion of sequence space, in support of the view that the virus replicates close to the error threshold for maintenance of genetic information. PMID:21917974

  19. Lethal infection thresholds of Paenibacillus larvae for honeybee drone and worker larvae (Apis mellifera).

    PubMed

    Behrens, Dieter; Forsgren, Eva; Fries, Ingemar; Moritz, Robin F A

    2010-10-01

    We compared the mortality of honeybee (Apis mellifera) drone and worker larvae from a single queen under controlled in vitro conditions following infection with Paenibacillus larvae, a bacterium causing the brood disease American Foulbrood (AFB). We also determined absolute P. larvae cell numbers and lethal titres in deceased individuals of both sexes up to 8 days post infection using quantitative real-time PCR (qPCR). Our results show that in drones the onset of infection induced mortality is delayed by 1 day, the cumulative mortality is reduced by 10% and P. larvae cell numbers are higher than in worker larvae. Since differences in bacterial cell titres between sexes can be explained by differences in body size, larval size appears to be a key parameter for a lethal threshold in AFB tolerance. Both means and variances for lethal thresholds are similar for drone and worker larvae suggesting that drone resistance phenotypes resemble those of related workers. PMID:20545737

  20. Efficient synthetic inhibitors of anthrax lethal factor

    PubMed Central

    Forino, Martino; Johnson, Sherida; Wong, Thiang Y.; Rozanov, Dmitri V.; Savinov, Alexei Y.; Li, Wei; Fattorusso, Roberto; Becattini, Barbara; Orry, Andrew J.; Jung, Dawoon; Abagyan, Ruben A.; Smith, Jeffrey W.; Alibek, Ken; Liddington, Robert C.; Strongin, Alex Y.; Pellecchia, Maurizio

    2005-01-01

    Inhalation anthrax is a deadly disease for which there is currently no effective treatment. Bacillus anthracis lethal factor (LF) metalloproteinase is an integral component of the tripartite anthrax lethal toxin that is essential for the onset and progression of anthrax. We report here on a fragment-based approach that allowed us to develop inhibitors of LF. The small-molecule inhibitors we have designed, synthesized, and tested are highly potent and selective against LF in both in vitro tests and cell-based assays. These inhibitors do not affect the prototype human metalloproteinases that are structurally similar to LF. Initial in vivo evaluation of postexposure efficacy of our inhibitors combined with antibiotic ciprofloxican against B. anthracis resulted in significant protection. Our data strongly indicate that the scaffold of inhibitors we have identified is the foundation for the development of novel, safe, and effective emergency therapy of postexposure inhalation anthrax. PMID:15983377

  1. Bullying and Lethal Acts of School Violence

    Microsoft Academic Search

    Jeffrey A. Daniels; Mary C. Bradley

    \\u000a In Chap. 3, we address a topic that has received considerable research attention over the past decade and has been implicated as a causal\\u000a factor in LSV. It has been reported that many lethal school shootings were in part in retaliation for being bullied. Within\\u000a this chapter, we address prevalence of bullying in the USA and then discuss different forms

  2. Substrate specificity of the anthrax lethal factor

    Microsoft Academic Search

    M. Yu. Zakharova; S. A. Dubiley; D. M. Chudakov; A. G. Gabibov; I. G. Shemyakin; A. V. Kolesnikov

    2008-01-01

    The lethal factor (LF), a high-specific metalloprotease, is a subunit of the B. anthracis toxin. In susceptible cells, LF has a toxic effect due to inactivation of MKK-family kinases (mitogen-activated serine?threonine kinase kinases) and presumably of some other proteins. To develop an approach to neutralization of the anthrax toxin effect, the entire pattern of LF cell targets should be determined.

  3. Lethal interpersonal violence in the middle pleistocene.

    PubMed

    Sala, Nohemi; Arsuaga, Juan Luis; Pantoja-Pérez, Ana; Pablos, Adrián; Martínez, Ignacio; Quam, Rolf M; Gómez-Olivencia, Asier; Bermúdez de Castro, José María; Carbonell, Eudald

    2015-01-01

    Evidence of interpersonal violence has been documented previously in Pleistocene members of the genus Homo, but only very rarely has this been posited as the possible manner of death. Here we report the earliest evidence of lethal interpersonal violence in the hominin fossil record. Cranium 17 recovered from the Sima de los Huesos Middle Pleistocene site shows two clear perimortem depression fractures on the frontal bone, interpreted as being produced by two episodes of localized blunt force trauma. The type of injuries, their location, the strong similarity of the fractures in shape and size, and the different orientations and implied trajectories of the two fractures suggest they were produced with the same object in face-to-face interpersonal conflict. Given that either of the two traumatic events was likely lethal, the presence of multiple blows implies an intention to kill. This finding shows that the lethal interpersonal violence is an ancient human behavior and has important implications for the accumulation of bodies at the site, supporting an anthropic origin. PMID:26018668

  4. Lethal Interpersonal Violence in the Middle Pleistocene

    PubMed Central

    Sala, Nohemi; Arsuaga, Juan Luis; Pantoja-Pérez, Ana; Pablos, Adrián; Martínez, Ignacio; Quam, Rolf M.; Gómez-Olivencia, Asier; Bermúdez de Castro, José María; Carbonell, Eudald

    2015-01-01

    Evidence of interpersonal violence has been documented previously in Pleistocene members of the genus Homo, but only very rarely has this been posited as the possible manner of death. Here we report the earliest evidence of lethal interpersonal violence in the hominin fossil record. Cranium 17 recovered from the Sima de los Huesos Middle Pleistocene site shows two clear perimortem depression fractures on the frontal bone, interpreted as being produced by two episodes of localized blunt force trauma. The type of injuries, their location, the strong similarity of the fractures in shape and size, and the different orientations and implied trajectories of the two fractures suggest they were produced with the same object in face-to-face interpersonal conflict. Given that either of the two traumatic events was likely lethal, the presence of multiple blows implies an intention to kill. This finding shows that the lethal interpersonal violence is an ancient human behavior and has important implications for the accumulation of bodies at the site, supporting an anthropic origin. PMID:26018668

  5. Etv2 rescues Flk1 mutant embryoid bodies

    PubMed Central

    Rasmussen, Tara L.; Martin, Cindy M.; Walter, Camille A.; Shi, Xiaozhong; Perlingeiro, Rita; Koyano-Nakagawa, Naoko; Garry, Daniel J.

    2013-01-01

    Independent mouse knockouts of Etv2 and Flk1 are embryonic lethal and lack hematopoietic and endothelial lineages. We previously reported that Flk1 activates Etv2 in the initiation of hematopoiesis and vasculogenesis. However, Flk1 and its ligand VEGF are expressed throughout development, from E7.0 to adulthood, whereas Etv2 is expressed only transiently during embryogenesis. These observations suggest a complex regulatory interaction between Flk1 and Etv2. To further examine the Flk1 and Etv2 regulatory interaction, we transduced Etv2 and Flk1 mutant ES cells with viral integrants that inducibly overexpress Flk1 or Etv2. We demonstrated that forced expression of Etv2 rescued the hematopoietic and endothelial potential of differentiating Flk1 and Etv2 mutant cells. We further discovered that forced expression of Flk1 can rescue that of the Flk1, but not Etv2 mutant cells. Therefore, we conclude that the requirement for Flk1 can be bypassed by expressing Etv2, supporting the notion that disruption of Etv2 expression is responsible for the early phenotypes of the Etv2 and Flk1 mutant embryos. PMID:23606617

  6. Lethal and sub-lethal effects of UVB on juvenile Biomphalaria glabrata (Mollusca: Pulmonata).

    PubMed

    Ruelas, Debbie S; Karentz, Deneb; Sullivan, John T

    2006-11-01

    Although Schistosoma mansoni occurs mainly in the tropics, where intense levels of solar radiation are present, the impact of ultraviolet (UV) light on schistosome transmission is not known. The purpose of this study was to investigate potential effects of UVB (290-320nm) on juvenile Biomphalaria glabrata, the snail intermediate host of S. mansoni. Albino and wild-type snails were exposed to doses of UVB from UV-fluorescent lamps, and the following were measured: survival, photoreactivation (light-mediated DNA repair), effects on feeding behavior, and morphological tissue abnormalities. Irradiation with UVB is lethal to B. glabrata in a dose-dependent manner. Exposure to white light subsequent to UVB irradiation enhances survival, probably by photoreactivation. The shell offers some, but not complete, protection. Experiments in which UVB transmittance through the shell was blocked with black nail polish suggest that injury to both exposed (headfoot) and shell-enclosed (mantle and visceral mass) tissues contributes to mortality in lethally irradiated snails. Wild-type (pigmented) snails are less susceptible to lethal effects of UVB than albino snails, and they may be more capable of photoreactivation. UVB exposure inhibits snail feeding behavior, and causes tentacle forks and growths on the headfoot. Thus, UVB may influence the life cycle of S. mansoni by both lethal and sub-lethal damage to the snail intermediate host. However, the ability of snails to photoreactivate may mitigate these effects. PMID:16996081

  7. Lethal and Sub-lethal Effects of UVB on Juvenile Biomphalaria glabrata (Mollusca: Pulmonata)

    PubMed Central

    Ruelas, Debbie S.; Karentz, Deneb; Sullivan, John T.

    2007-01-01

    Although Schistosoma mansoni occurs mainly in the tropics, where intense levels of solar radiation are present, the impact of ultraviolet (UV) light on schistosome transmission is not known. The purpose of this study was to investigate potential effects of UVB (290–320 nm) on juvenile Biomphalaria glabrata, the snail intermediate host of S. mansoni. Albino and wild type snails were exposed to doses of UVB from UV-fluorescent lamps, and the following were measured: survival, photoreactivation (light-mediated DNA repair), effects on feeding behavior, and morphological tissue abnormalities. Irradiation with UVB is lethal to B. glabrata in a dose-dependent manner. Exposure to white light subsequent to UVB irradiation enhances survival, probably by photoreactivation. The shell offers some, but not complete, protection. Experiments in which UVB transmittance through the shell was blocked with black nail polish suggest that injury to both exposed (headfoot) and shell-enclosed (mantle and visceral mass) tissues contributes to mortality in lethally-irradiated snails. Wild-type (pigmented) snails are less susceptible to lethal effects of UVB than albino snails, and they may be more capable of photoreactivation. UVB exposure inhibits snail feeding behavior, and causes tentacle forks and growths on the headfoot. Thus, UVB may influence the life cycle of S. mansoni by both lethal and sub-lethal damage to the snail intermediate host. However, the ability of snails to photoreactivate may mitigate these effects. PMID:16996081

  8. Bipyridine (2,2'-dipyridyl) potentiates Escherichia coli lethality induced by nitrogen mustard mechlorethamine.

    PubMed

    De Alencar, T A M; Wilmart-Gonçalves, T C; Vidal, L S; Fortunato, R S; Leitão, A C; Lage, C

    2014-07-01

    Alkylating agents are used in anti-tumor chemotherapy because they bind covalently to DNA and generate adducts that may lead to cell death. Bifunctional (HN2) and monofunctional (HN1) nitrogen are two such agents, and HN2 was the first drug successfully employed in anti-leukemia chemotherapy. Currently, HN2 is used either alone or combined with other drugs to treat Hodgkin's disease. It is well known that several crosslinking agents require metabolic activation via reactive oxygen species (ROS) to exert their lethal effects. The objective of this work was therefore to determine whether the abovementioned mustards would also require metabolic activation to exert lethal action against Escherichia coli. For this purpose, we measured survival following exposure to HN2 in E. coli strains that were deficient in nucleotide excision repair (uvrA NER mutant), base excision repair (xthA nfo nth fpg BER mutant) or superoxide dismutase (sodAB mutant) activity. We also performed the same experiments in cells pretreated with an iron chelator (2,2'-dipyridyl, DIP). The NER and BER mutants were only sensitive to HN2 treatment (survival rates similar to those of the wild-type were achieved with 5-fold lower HN2 doses). However, wild-type and sodAB strains were not sensitive to treatment with HN2. In all tested strains, survival dropped by 2.5-fold following pretreatment with DIP compared to treatment with HN2 alone. Furthermore, DIP treatment increased ROS generation in both wild type and sodAB-deficient strains. Based on these data and on the survival of the SOD-deficient strain, we suggest that the increased production of ROS caused by Fe(2+) chelation may potentiate the lethal effects of HN2 but not HN1. This potentiation may arise as a consequence of enhancement in the number of or modification of the type of lesions formed. No sensitization was observed for the non-crosslinkable HN2 analog, HN1. PMID:24632511

  9. A novel histone H4 mutant defective in nuclear division and mitotic chromosome transmission.

    PubMed Central

    Smith, M M; Yang, P; Santisteban, M S; Boone, P W; Goldstein, A T; Megee, P C

    1996-01-01

    The histone proteins are essential for the assembly and function of th e eukaryotic chromosome. Here we report the first isolation of a temperature-sensitive lethal histone H4 mutant defective in mitotic chromosome transmission Saccharomyces cerevisiae. The mutant requires two amino acid substitutions in histone H4: a lethal Thr-to-Ile change at position 82, which lies within one of the DNA-binding surfaces of the protein, and a substitution of Ala to Val at position 89 that is an intragenic suppressor. Genetic and biochemical evidence shows that the mutant histone H4 is temperature sensitive for function but not for synthesis, deposition, or stability. The chromatin structure of 2 micrometer circle minichromosomes is temperature sensitive in vivo, consistent with a defect in H4-DNA interactions. The mutant also has defects in transcription, displaying weak Spt- phenotypes. At the restrictive temperature, mutant cells arrest in the cell cycle at nuclear division, with a large bud, a single nucleus with 2C DNA content, and a short bipolar spindle. At semipermissive temperatures, the frequency of chromosome loss is elevated 60-fold in the mutant while DNA recombination frequencies are unaffected. High-copy CSE4, encoding an H3 variant related to the mammalian CENP-A kinetochore antigen, was found to suppress the temperature sensitivity of the mutant without suppressing the Spt- transcription defect. These genetic, biochemical, and phenotypic results indicate that this novel histone H4 mutant defines one or more chromatin-dependent steps in chromosome segregation. PMID:8622646

  10. Characterization of Francisella tularensis Schu S4 defined mutants as live-attenuated vaccine candidates.

    PubMed

    Santiago, Araceli E; Mann, Barbara J; Qin, Aiping; Cunningham, Aimee L; Cole, Leah E; Grassel, Christen; Vogel, Stefanie N; Levine, Myron M; Barry, Eileen M

    2015-08-01

    Francisella tularensis (Ft), the etiological agent of tularemia and a Tier 1 select agent, has been previously weaponized and remains a high priority for vaccine development. Ft tularensis (type A) and Ft holarctica (type B) cause most human disease. We selected six attenuating genes from the live vaccine strain (LVS; type B), F. novicida and other intracellular bacteria: FTT0507, FTT0584, FTT0742, FTT1019c (guaA), FTT1043 (mip) and FTT1317c (guaB) and created unmarked deletion mutants of each in the highly human virulent Ft strain Schu S4 (Type A) background. FTT0507, FTT0584, FTT0742 and FTT1043 Schu S4 mutants were not attenuated for virulence in vitro or in vivo. In contrast, Schu S4 gua mutants were unable to replicate in murine macrophages and were attenuated in vivo, with an i.n. LD50 > 10(5) CFU in C57BL/6 mice. However, the gua mutants failed to protect mice against lethal challenge with WT Schu S4, despite demonstrating partial protection in rabbits in a previous study. These results contrast with the highly protective capacity of LVS gua mutants against a lethal LVS challenge in mice, and underscore differences between these strains and the animal models in which they are evaluated, and therefore have important implications for vaccine development. PMID:25986219

  11. Characterization of Francisella tularensis Schu S4 defined mutants as live-attenuated vaccine candidates

    PubMed Central

    Santiago, Araceli E.; Mann, Barbara J.; Qin, Aiping; Cunningham, Aimee L.; Cole, Leah E.; Grassel, Christen; Vogel, Stefanie N.; Levine, Myron M.; Barry, Eileen M.

    2015-01-01

    Francisella tularensis (Ft), the etiological agent of tularemia and a Tier 1 select agent, has been previously weaponized and remains a high priority for vaccine development. Ft tularensis (type A) and Ft holarctica (type B) cause most human disease. We selected six attenuating genes from the live vaccine strain (LVS; type B), F. novicida and other intracellular bacteria: FTT0507, FTT0584, FTT0742, FTT1019c (guaA), FTT1043 (mip) and FTT1317c (guaB) and created unmarked deletion mutants of each in the highly human virulent Ft strain Schu S4 (Type A) background. FTT0507, FTT0584, FTT0742 and FTT1043 Schu S4 mutants were not attenuated for virulence in vitro or in vivo. In contrast, Schu S4 gua mutants were unable to replicate in murine macrophages and were attenuated in vivo, with an i.n. LD50 > 105 CFU in C57BL/6 mice. However, the gua mutants failed to protect mice against lethal challenge with WT Schu S4, despite demonstrating partial protection in rabbits in a previous study. These results contrast with the highly protective capacity of LVS gua mutants against a lethal LVS challenge in mice, and underscore differences between these strains and the animal models in which they are evaluated, and therefore have important implications for vaccine development. PMID:25986219

  12. Lethal Forethought: Delayed Reward Discounting Differentiates High- and Low-Lethality Suicide Attempts in Old Age

    PubMed Central

    Dombrovski, Alexandre Y.; Szanto, Katalin; Siegle, Greg J.; Wallace, Meredith L.; Forman, Steven D.; Sahakian, Barbara; Reynolds, Charles F.; Clark, Luke

    2011-01-01

    Background The decision to commit suicide may be impulsive, but lethal suicidal acts often involve planning and forethought. People who attempt suicide make disadvantageous decisions in other contexts, but nothing is known about the way they decide about the future. Can the willingness to postpone future gratification differentiate between individuals prone to serious, premeditated and less serious, unplanned suicidal acts? Methods Four groups of depressed participants aged 60+ made choices between smaller immediate and larger delayed monetary rewards: 15 who made high-lethality suicide attempts, 14 who made low-lethality suicide attempts, 12 who seriously contemplated suicide, and 42 people with depression but no history of suicidal thoughts. The reference group was 31 psychiatrically healthy elders. Results Individuals who had made low-lethality attempts displayed an exaggerated preference for immediate rewards compared to non-suicidal depressed and healthy controls. Those who had carried out high-lethality suicide attempts were more willing to delay future rewards, compared to low-lethality attempters. Better planned suicide attempts were also associated with willingness to wait for larger rewards. These effects were unchanged after accounting for education, global cognitive function, substance use disorders, psychotropic medications, and possible brain injury from attempts. Discount rates were correlated with having debt but were not significantly associated with income, hopelessness, depressive severity, premorbid IQ, age at first attempt, or choice of violent means. Conclusions While clinicians often focus on impulsivity in patients at risk for suicide, these data suggest that identifying biological characteristics and treatments for non-impulsive suicidal older people may be even more important. PMID:21329911

  13. Bacillus anthracis Lethal Toxin Reduces Human Alveolar Epithelial Barrier Function

    PubMed Central

    Langer, Marybeth; Duggan, Elizabeth Stewart; Booth, John Leland; Patel, Vineet Indrajit; Zander, Ryan A.; Silasi-Mansat, Robert; Ramani, Vijay; Veres, Tibor Zoltan; Prenzler, Frauke; Sewald, Katherina; Williams, Daniel M.; Coggeshall, Kenneth Mark; Awasthi, Shanjana; Lupu, Florea; Burian, Dennis; Ballard, Jimmy Dale; Braun, Armin

    2012-01-01

    The lung is the site of entry for Bacillus anthracis in inhalation anthrax, the deadliest form of the disease. Bacillus anthracis produces virulence toxins required for disease. Alveolar macrophages were considered the primary target of the Bacillus anthracis virulence factor lethal toxin because lethal toxin inhibits mouse macrophages through cleavage of MEK signaling pathway components, but we have reported that human alveolar macrophages are not a target of lethal toxin. Our current results suggest that, unlike human alveolar macrophages, the cells lining the respiratory units of the lung, alveolar epithelial cells, are a target of lethal toxin in humans. Alveolar epithelial cells expressed lethal toxin receptor protein, bound the protective antigen component of lethal toxin, and were subject to lethal-toxin-induced cleavage of multiple MEKs. These findings suggest that human alveolar epithelial cells are a target of Bacillus anthracis lethal toxin. Further, no reduction in alveolar epithelial cell viability was observed, but lethal toxin caused actin rearrangement and impaired desmosome formation, consistent with impaired barrier function as well as reduced surfactant production. Therefore, by compromising epithelial barrier function, lethal toxin may play a role in the pathogenesis of inhalation anthrax by facilitating the dissemination of Bacillus anthracis from the lung in early disease and promoting edema in late stages of the illness. PMID:23027535

  14. Rapidly lethal dermatomyositis associated with cutaneous lymphangitis carcinomatosa

    PubMed Central

    Resende, Cristina; Araújo, Catarina; Duarte, Maria Luz; Brito, Celeste

    2013-01-01

    A 70-year-old woman with a recent diagnosis of dermatomyositis (DM) presented to the dermatology department for study of a probably paraneoplastic syndrome. On examination, we observed discrete, indurated, reddish, painful plaques and nodules on her abdomen and both thighs. A cutaneous biopsy from an abdominal nodule, performed as part of the paraneoplastic workup, was suggestive of cutaneous lymphangitis carcinomatosa, secondary to unknown malignancy. An extensive investigation to locate the site of the primary tumour revealed no specific findings. A course of palliative chemotherapy with cisplatin and 5-fluorouracil was then given, but the patient’s condition deteriorated and 6?months after her initial observation the patient died. We describe this case because, to our knowledge, the association between DM and cutaneous lymphangitis carcinomatosa has not been described yet in the literature and to highlight that, DM can be a rapidly lethal disease. PMID:23761617

  15. Asthma and risk of lethal prostate cancer in the Health Professionals Follow-Up Study.

    PubMed

    Platz, Elizabeth A; Drake, Charles G; Wilson, Kathryn M; Sutcliffe, Siobhan; Kenfield, Stacey A; Mucci, Lorelei A; Stampfer, Meir J; Willett, Walter C; Camargo, Carlos A; Giovannucci, Edward

    2015-08-15

    Inflammation, and more generally, the immune response are thought to influence the development of prostate cancer. To determine the components of the immune response that are potentially contributory, we prospectively evaluated the association of immune-mediated conditions, asthma and hayfever, with lethal prostate cancer risk in the Health Professionals Follow-up Study. We included 47,880 men aged 40-75 years with no prior cancer diagnosis. On the baseline questionnaire in 1986, the men reported diagnoses of asthma and hayfever and year of onset. On the follow-up questionnaires, they reported new asthma and prostate cancer diagnoses. We used Cox proportional hazards regression to estimate relative risks (RRs). In total, 9.2% reported ever having been diagnosed with asthma. In all, 25.3% reported a hayfever diagnosis at baseline. During 995,176 person-years of follow-up by 2012, we confirmed 798 lethal prostate cancer cases (diagnosed with distant metastases, progressed to distant metastasis or died of prostate cancer [N?=?625]). Ever having a diagnosis of asthma was inversely associated with risk of lethal (RR?=?0.71, 95% confidence interval [CI]?=?0.51-1.00) and fatal (RR?=?0.64, 95% CI?=?0.42-0.96) disease. Hayfever with onset in the distant past was possibly weakly positively associated with risk of lethal (RR?=?1.10, 95% CI?=?0.92-1.33) and fatal (RR?=?1.12, 95% CI?=?0.91-1.37) disease. Men who were ever diagnosed with asthma were less likely to develop lethal and fatal prostate cancer. Our findings may lead to testable hypotheses about specific immune profiles in the etiology of lethal prostate cancer. PMID:25648070

  16. [Semilethal spotted mutants of Chlorella].

    PubMed

    Shabanova, E A

    1975-01-01

    Mutant colonies of Chorella vulgaris Beijer, having the region of colourless cells either in the center or in the periphery of a colony, are found. Spontaneous mutation rate varied within 1-40-10(5). The size of a mutant colony comprised about 1/2-1/3 of the diameter of a middle initial strain colony. Colonies with a mutant sector were also observed besides completely mutant colonies. Ways of the formation of mutant phenotypes are studied. It is found that from the initial spotted green colony those of the type "death in the periphery" and, through a number of intermediate stages, "death in the center" are formed. The colony development can stop at some successive stage or to result in the death of all the cells. The period of forming the mutant phenotype is found to depend on the colony growth rate. PMID:1228059

  17. Lethal mobilization of DDT by cowbirds

    USGS Publications Warehouse

    Van Velzen, A.C.; Stiles, W.B.; Stickel, L.F.

    1972-01-01

    This study is an experimental demonstration of lethal mobilization of DDT by brown-headed cowbirds (Molothrus ater) and the effects of food deprivation on the distribution and loss of DDT, DDD, and DDE. The principal experimental group consisted of 20 birds fed a dietary dosage of 100 ppm of DDT for 13 days. After 2 days of full rations of untreated food, they were subjected to food restriction. Food was reduced to 43 percent of normal. Seven of the 20 birds died within 4 days. No birds died in the three control groups, treated as follows: ( 1 ) 20 birds fed 100 ppm DDT for 13 days and full rations of untreated food thereafter, (2) 20 birds fed only untreated food but subjected to food restriction, and (3) 20 birds fed full rations of untreated food throughout. In a pilot study, birds were fed 100, 200, or 300 ppm of DDT and subjected to two periods of food restriction, the first of these immediately after dosage ceased and the second 4 months later. DDT-dosed birds from all dosage levels died in each period of food restriction. Before the weight loss that accompanied food restriction, the brains of DDT-dosed birds had concentrations of DDT and DDD that were far below the lethal range. Concentrations increased rapidly to lethal levels. In these birds, DDT in carcasses decreased while DDD increased. DDT-dosed birds that died during food restriction lost 16 percent of their total body burden of DDT + DDD + DDE, 21 percent of their weight, and 81 percent of their fat. The DDT-dosed birds that were subjected to food restriction but survived lost a significantly greater proportion of their body burden of residues than similarly dosed birds not subjected to weight loss. Brain levels of DDT and DDD in birds that died during food restriction soon after dosage did not differ significantly from brain levels of birds that died in a period of food restriction 4 months after dosage. Concentrations of DDE were significantly higher in the latter group, although they were lower than concentrations considered to be lethal. In contrast, carcass levels of DDT and DDD were significantly lower, and DDE was only slightly higher, in the birds that died in the second period of food restriction. It is concluded that stored DDT residues present a hazard to birds, which utilize stored fat during periods of stress due to reproduction, cold weather, disease, injury, limited food supply, or migration.

  18. Isolation and Characterization of Sex-Linked Female-Sterile Mutants in DROSOPHILA MELANOGASTER

    PubMed Central

    Gans, Madeleine; Audit, Claudie; Masson, Michele

    1975-01-01

    The purpose of the experiments described was to identify X chromosome genes functioning mainly or exclusively during oogenesis. Two mutagenesis experiments were carried out with ethyl methane sulfonate. Following treatment inducing 60% lethals, 9% of the treated X chromosomes carried a female sterility mutation which did not otherwise seriously affect viability. Among —95 isolated mutants, 19 were heat-sensitive and 5 cold-sensitive. The mutants have been classified as follows: I (16 mutants; 12 complementation groups): the females laid few or no eggs; the defect concerned either ovulation or oogenesis. II (37 mutants; 18 complementation groups): the female laid morphologically abnormal eggs, often with increased membrane permeability. III A (13 mutants; at least 8 complementation groups): the homozygous females were sterile if mated to mutant males; their progeny (homo- and hemizygous) died at a late embryonic stage (11 mutants), at the larval stage (1 mutant) or at the pupal stage (1 mutant). However fertility was partly restored by breeding to wild-type males as shown by survival of some heterozygous descendants. III B (29 mutants; 22 complementation groups): the fertility of the females was not restored by breeding to a wild-type male. Most of the eggs of 13 of the mutants died at a late stage of embryogenesis. The eggs of the others ceased development earlier or, perhaps, remained unfertilized. The distribution of the number of mutants per complementation group led to an estimation of a total of about 150 X-linked genes involved in female fertility. The females of three mutants, heat-sensitive and totally sterile at 29°, produced at a lower temperature descendants morphologically abnormal or deprived of germ cells. Three other mutants not described in detail showed a reduction in female fertility with many descendants lacking germ cells. A desirable mutant which was not recovered was one with normal fertile females producing descendants which, regardless of their genotype, bore specific morphological abnormalities. The value of the mutants isolated for analysis of the complex processes leading to egg formation and initiation of development is discussed. PMID:814037

  19. Selective killing of K-ras mutant cancer cells by small molecule inducers of oxidative stress

    PubMed Central

    Shaw, Alice T.; Winslow, Monte M.; Magendantz, Margaret; Ouyang, Chensi; Dowdle, James; Subramanian, Aravind; Lewis, Timothy A.; Maglathin, Rebecca L.; Tolliday, Nicola; Jacks, Tyler

    2011-01-01

    Activating K-RAS mutations are the most frequent oncogenic mutations in human cancer. Numerous downstream signaling pathways have been shown to be deregulated by oncogenic K-ras. However, to date there are still no effective targeted therapies for this genetically defined subset of patients. Here we report the results of a small molecule, synthetic lethal screen using mouse embryonic fibroblasts derived from a mouse model harboring a conditional oncogenic K-rasG12D allele. Among the >50,000 compounds screened, we identified a class of drugs with selective activity against oncogenic K-ras–expressing cells. The most potent member of this class, lanperisone, acts by inducing nonapoptotic cell death in a cell cycle- and translation-independent manner. The mechanism of cell killing involves the induction of reactive oxygen species that are inefficiently scavenged in K-ras mutant cells, leading to oxidative stress and cell death. In mice, treatment with lanperisone suppresses the growth of K-ras–driven tumors without overt toxicity. Our findings establish the specific antitumor activity of lanperisone and reveal oxidative stress pathways as potential targets in Ras-mediated malignancies. PMID:21555567

  20. Synthetic lethal screening in the mammalian central nervous system identifies Gpx6 as a modulator of Huntington's disease.

    PubMed

    Shema, Reut; Kulicke, Ruth; Cowley, Glenn S; Stein, Rachael; Root, David E; Heiman, Myriam

    2015-01-01

    Huntington's disease, the most common inherited neurodegenerative disease, is characterized by a dramatic loss of deep-layer cortical and striatal neurons, as well as morbidity in midlife. Human genetic studies led to the identification of the causative gene, huntingtin. Recent genomic advances have also led to the identification of hundreds of potential interacting partners for huntingtin protein and many hypotheses as to the molecular mechanisms whereby mutant huntingtin leads to cellular dysfunction and death. However, the multitude of possible interacting partners and cellular pathways affected by mutant huntingtin has complicated efforts to understand the etiology of this disease, and to date no curative therapeutic exists. To address the general problem of identifying the disease-phenotype contributing genes from a large number of correlative studies, here we develop a synthetic lethal screening methodology for the mammalian central nervous system, called SLIC, for synthetic lethal in the central nervous system. Applying SLIC to the study of Huntington's disease, we identify the age-regulated glutathione peroxidase 6 (Gpx6) gene as a modulator of mutant huntingtin toxicity and show that overexpression of Gpx6 can dramatically alleviate both behavioral and molecular phenotypes associated with a mouse model of Huntington's disease. SLIC can, in principle, be used in the study of any neurodegenerative disease for which a mouse model exists, promising to reveal modulators of neurodegenerative disease in an unbiased fashion, akin to screens in simpler model organisms. PMID:25535386

  1. Suicide Intent and Accurate Expectations of Lethality: Predictors of Medical Lethality of Suicide Attempts

    ERIC Educational Resources Information Center

    Brown, Gregory K.; Henriques, Gregg R.; Sosdjan, Daniella; Beck, Aaron T.

    2004-01-01

    The degree of intent to commit suicide and the severity of self-injury were examined in individuals (N = 180) who had recently attempted suicide. Although a minimal association was found between the degree of suicide intent and the degree of lethality of the attempt, the accuracy of expectations about the likelihood of dying was found to moderate…

  2. Apparent lethal concentrations of pyrolysis products of some polymeric materials

    NASA Technical Reports Server (NTRS)

    Hilado, C. J.; Marcussen, W. H.; Furst, A.; Kourtides, D. A.; Parker, J. A.

    1976-01-01

    Thirty-nine samples of polymeric materials were evaluated to determine the apparent lethal concentrations of their pyrolysis products. The materials were compared on the basis of the apparent lethal concentration for 50 percent of the test animals. Relative toxicity rankings based o apparent lethal concentration values can differ significantly depending on whether they are based on weight of sample charged or weight of sample pyrolyzed. The ranking of polyphenylene sulfide is particularly sensitive to this difference.

  3. Antenatal diagnosis of lethal skeletal dysplasias.

    PubMed

    Tretter, A E; Saunders, R C; Meyers, C M; Dungan, J S; Grumbach, K; Sun, C C; Campbell, A B; Wulfsberg, E A

    1998-02-17

    Lethal skeletal dysplasias (LSD) are a heterogeneous group of rare but important genetic disorders characterized by abnormal growth and development of bone and cartilage. We describe the diagnosis and outcome of 29 cases of lethal skeletal dysplasias evaluated between January 1989 and December 1996 at the University of Maryland Medical Center and the Ultrasound Institute of Baltimore. Two cases presented at delivery with no prenatal care while the remaining 27 cases were identified by antenatal sonography. Final diagnoses included thanatophoric dysplasia (14), osteogenesis imperfecta, type II (6), achondrogenesis (2), short rib syndromes (3), campomelic syndrome (2), atelosteogenesis (1), and no evidence of a skeletal dysplasia (1). Twenty out of 27 pregnancies were terminated with an average at detection of 21.6 weeks. The other 7 pregnancies that went on to deliver had an average age at detection of 29.2 weeks. Fetal abnormalities in the terminated pregnancies were identified at a significantly earlier gestational age (P = 0.0016) than the pregnancies that continued. While the identification of LSD by sonography was excellent (26/27), only 13/27 (48%) were given an accurate specific antenatal diagnosis. In 8/14 (57%) cases with an inaccurate or nonspecific diagnosis there was a significant or crucial change in the genetic counseling. Thus, while antenatal sonography is an excellent method for discovering LSD, clinical examination, radiographs, and autopsy are mandatory for making a specific diagnosis. PMID:9489797

  4. ECB deacylase mutants

    DOEpatents

    Arnold, Frances H. (Pasadena, CA); Shao, Zhixin (Penzberg, DE); Zhao, Huimin (San Diego, CA); Giver, Lorraine J. (Sunnyvale, CA)

    2002-01-01

    A method for in vitro mutagenesis and recombination of polynucleotide sequences based on polymerase-catalyzed extension of primer oligonucleotides is disclosed. The method involves priming template polynucleotide(s) with random-sequences or defined-sequence primers to generate a pool of short DNA fragments with a low level of point mutations. The DNA fragments are subjected to denaturization followed by annealing and further enzyme-catalyzed DNA polymerization. This procedure is repeated a sufficient number of times to produce full-length genes which comprise mutants of the original template polynucleotides. These genes can be further amplified by the polymerase chain reaction and cloned into a vector for expression of the encoded proteins.

  5. The Developmental Genetics of the Temperature-Sensitive Lethal Allele of the Suppressor of Forked, l(1)su(f)ts67g, in DROSOPHILA MELANOGASTER

    PubMed Central

    Dudick, Marianne E.; Wright, Theodore R. F.; Brothers, Lynda Lee

    1974-01-01

    A temperature-sensitive lethal allele of suppressor of forked, l(1)su(f)ts67g (ts67), has been discovered and characterized as follows: Flies which are hemizygous for ts67 live at 18° and 25° but die at 30° primarily as larvae. The temperature-sensitive period for ts67 homozygotes or hemizygotes begins in second instar and ends at pupation. ts67 is lethal at 30° when heterozygous with suppressor of forked (su(f)), a deficiency for suppressor of forked (su(f)-), and a non-conditional lethal allele of suppressor of forked (3DES). It is viable at 30° when heterozygous with the wild-type allele of suppressor of forked. At 25° but not at 18° forked bristles are suppressed in flies of the following genotypes: fsts67/Y, fsts67/fsts67, fsts67/fssu(f), futs67/fs3DES, futs67/fssu(f)-, futs67/fssu(f). There is some suppression of forked bristles at 25° in the heterozygote, fsts67/fs+su(f). The forked bristle phenotype is not suppressed at either temperature in flies of the genotypes futs67/Y, futs67/futs67/ (fs and fu indicating suppressible and unsuppressible alleles of forked). The temperature-sensitive period for suppression of forked bristles begins at pupation and extends through the period of bristle synthesis. The deficiency phenotype (bristles reduced in size or absent, wing wrinkled or blistered, eyes rough) typical of flies of the genotype fssu(f)/fssu(f)- at 18° and 25°, is exhibited by flies of the genotypes fsts67/fssu(f)- at 25° and futs67/fssu(f) at 29°. An allele of lozenge (lz1) which can be suppressed by su(f) is suppressed at 25° but not at 18° in lz1ts67/Y males. ts67 homozygous females are fertile at 25° but sterile at 30°. The hypothesis is discussed that the su(f) locus codes for a ribosomal protein and that suppression and enhancement are affected by mutations at the locus by mutant ribosome-induced misreading. The possibility is presented that ts67 may be used to determine the translation time in development of any gene. PMID:4208858

  6. Establishment of embryonic stem cell lines from preimplantation mouse embryos homozygous for lethal mutations in the t-complex.

    PubMed

    Martin, G R; Silver, L M; Fox, H S; Joyner, A L

    1987-05-01

    We have determined the frequency at which embryonic stem cell (ESC) lines can be established from inner cell masses (ICMs) isolated from blastocysts homozygous for lethal mutations in the mouse t-complex. Approximately one-third of the expected number, 3/29, of the ESC lines established from embryos obtained by inter-se mating of +/tw18 mice are homozygous for the tw18 haplotype. These tw18/tw18 ESC lines form a variety of cell types in vitro and in vivo, including mesodermal derivatives such as cartilage and muscle. On the basis of these and data from other studies, we suggest that the normal function of the gene represented by the tw18 lethal allele is required for multiplication/survival of mesodermal precursors in the embryo rather than the specification of the mesodermal lineage, and that the lethal effects of this mutation are expressed in only the highly structured environment of the early postimplantation embryo. In studies of the lethal tw5 haplotype, we found that 2/2 ESC lines obtained are mutant homozygotes. Analysis of these data, in conjunction with the results of our earlier study (Magnuson, T., Epstein, C. J., Silver, L. M., and Martin, G. R. (1982), Nature (London) 298, 750-753), suggests that homozygosity for the genes found in the tw5 haplotype does not reduce cell viability. By contrast, 0/16 ESC lines isolated from embryos obtained from matings of +/t0 mice are mutant homozygotes. Analysis of the genotypes of ICM-derived primary stem cell colonies suggests that t0 homozygous ICM cells are unable to undergo sufficient proliferation in vitro to give rise to ESC lines. PMID:2883053

  7. Distinct Regions of NLRP1B Are Required To Respond to Anthrax Lethal Toxin and Metabolic Inhibition

    PubMed Central

    Neiman-Zenevich, Jana; Liao, Kuo-Chieh

    2014-01-01

    Pattern recognition receptors monitor for signs of infection or cellular dysfunction and respond to these events by initiating an immune response. NLRP1B is a receptor that upon activation recruits multiple copies of procaspase-1, which promotes cytokine processing and a proinflammatory form of cell death termed pyroptosis. NLRP1B detects anthrax lethal toxin when the toxin cleaves an amino-terminal fragment from the protein. In addition, NLRP1B is activated when cells are deprived of glucose or treated with metabolic inhibitors, but the mechanism by which the resulting reduction in cytosolic ATP is sensed by NLRP1B is unknown. Here, we addressed whether these two activating signals of NLRP1B converge on a common sensing system. We show that an NLRP1B mutant lacking the amino-terminal region exhibits some spontaneous activity and fails to be further activated by lethal toxin. This mutant was still activated in cells depleted of ATP, however, indicating that the amino-terminal region is not the sole sensing domain of NLRP1B. Mutagenesis of the leucine-rich repeat domain of NLRP1B provided evidence that this domain is involved in autoinhibition of the receptor, but none of the mutants tested was specifically defective at sensing activating signals. Comparison of two alleles of NLRP1B that differed in their response to metabolic inhibitors, but not to lethal toxin, led to the finding that a repeated sequence in the function to find domain (FIIND) that arose from exon duplication facilitated detection of ATP depletion. These results suggest that distinct regions of NLRP1B detect activating signals. PMID:24935976

  8. An exome sequencing strategy to diagnose lethal autosomal recessive disorders.

    PubMed

    Ellard, Sian; Kivuva, Emma; Turnpenny, Peter; Stals, Karen; Johnson, Matthew; Xie, Weijia; Caswell, Richard; Lango Allen, Hana

    2015-03-01

    Rare disorders resulting in prenatal or neonatal death are genetically heterogeneous. For some conditions, affected fetuses can be diagnosed by ultrasound scan, but this is not usually possible until mid-gestation. There is often limited fetal DNA available for investigation. We investigated a strategy for diagnosing autosomal recessive lethal disorders in non-consanguineous pedigrees with multiple affected fetuses. Exome sequencing was performed to identify genes where each parent is heterozygous for a rare non-synonymous-coding or splicing variant. Putative pathogenic variants were tested for cosegregation in affected fetuses and unaffected siblings. In eight couples of European ancestry, we found on average 1.75 genes (range 0-4) where both parents were heterozygous for rare potentially deleterious variants. A proof-of-principle study detected heterozygous DYNC2H1 variants in a couple whose five fetuses had short-rib polydactyly. Prospective analysis of two couples with multiple pregnancy terminations for fetal akinesia syndrome was performed and a diagnosis was obtained in both the families. The first couple were each heterozygous for a previously reported GLE1 variant, p.Arg569His or p.Val617Met; both were inherited by their two affected fetuses. The second couple were each heterozygous for a novel RYR1 variant, c.14130-2A>G or p.Ser3074Phe; both were inherited by their three affected fetuses but not by their unaffected child. Biallelic GLE1 and RYR1 disease-causing variants have been described in other cases with fetal akinesia syndrome. We conclude that exome sequencing of parental samples can be an effective tool for diagnosing lethal recessive disorders in outbred couples. This permits early prenatal diagnosis in future pregnancies. PMID:24961629

  9. Examining lethality risk for rodent studies of primary blast lung injury.

    PubMed

    Hubbard, William Brad; Hall, Christina; Siva Sai Suijith Sajja, Venkata; Lavik, Erink; VandeVord, Pamela

    2014-01-01

    While protective measures have been taken to mitigate injury to the thorax during a blast exposure, primary blast lung injury (PBLI) is still evident in mounted/in vehicle cases during military conflicts. Moreover, civilians, who are unprotected from blast exposure, can be severely harmed by terrorist attacks that use improvised explosive devices (IEDs). Since the lungs are the most susceptible organ due to their air-filled nature, PBLI is one of the most serious injuries seen in civilian blast cases. Determining lethality threshold for rodent studies is crucial to guide experimental designs centered on therapies for survival after PBLI or mechanistic understanding of the injury itself. Using an Advanced Blast Simulator, unprotected rats were exposed to a whole body blast to induce PBLI. The one-hour survival rate was assessed to determine operating conditions for a 50% lethality rate. Macroscopic and histological analysis of lung was conducted using hematoxylin and eosin staining. Results demonstrated lethality risk trends based on static blast overpressure (BOP) for rodent models, which may help standardized animal studies and contribute to scaling to the human level. The need for a standardized method of producing PBLI is pressing and establishing standard curves, such as a lethality risk curve for lung blasts, is crucial for this condensing of BOP methods. PMID:25405409

  10. Ants defend aphids against lethal disease.

    PubMed

    Nielsen, Charlotte; Agrawal, Anurag A; Hajek, Ann E

    2010-04-23

    Social insects defend their own colonies and some species also protect their mutualist partners. In mutualisms with aphids, ants typically feed on honeydew produced by aphids and, in turn guard and shelter aphid colonies from insect natural enemies. Here we report that Formica podzolica ants tending milkweed aphids, Aphis asclepiadis, protect aphid colonies from lethal fungal infections caused by an obligate aphid pathogen, Pandora neoaphidis. In field experiments, bodies of fungal-killed aphids were quickly removed from ant-tended aphid colonies. Ant workers were also able to detect infective conidia on the cuticle of living aphids and responded by either removing or grooming these aphids. Our results extend the long-standing view of ants as mutualists and protectors of aphids by demonstrating focused sanitizing and quarantining behaviour that may lead to reduced disease transmission in aphid colonies. PMID:19923138

  11. Comparison of Lethal Zone Characteristics of Several Natural Fragmenting Warheads

    Microsoft Academic Search

    Berko ZECEVIC; Alan CATOVIC; Jasmin TERZIC

    Research of HE warheads lethal zone is very complex topic because of large number of controlled and independent, sometimes correlated, influencing factors. Capability for prediction of lethal zone is based on complexity of databases regarding natural fragmentation parameters, which should contain data about warhead body material characteristics, types of explosive charge, number, mass, initial velocity and spatial distribution of fragments,

  12. Anthrax lethal toxin: a weapon of multisystem destruction

    Microsoft Academic Search

    A. Agrawal; B. Pulendran

    2004-01-01

    Lethal toxin (LT) is a major virulence factor secreted by anthrax bacteria. It is composed of two proteins, PA (protective antigen) and LF (lethal factor). PA transports the LF inside the cell, where LF, a zinc-dependent metalloprotease cleaves the mitogen activated protein kinase kinase (MAPKK) enzymes of the mitogen activated protein kinase (MAPK) signaling pathway, thereby impairing their function. This

  13. Characterization of fig operon mutants of Francisella novicida U112.

    PubMed

    Kiss, Katalin; Liu, Wei; Huntley, Jason F; Norgard, Michael V; Hansen, Eric J

    2008-08-01

    Francisella species secrete a polycarboxylate siderophore that resembles rhizoferrin to acquire ferric iron. Several of the Francisella siderophore synthesis genes are contained in a Fur-regulated operon (designated fig or fsl) comprised of at least seven ORFs including fur. Reverse transcriptase-PCR showed transcriptional linkage between figD and figE and between figE and figF. Mutations were constructed in four of these ORFs (figB, figC, figD, and figE) in Francisella novicida U112. All four of these new mutants and a F. novicida figA mutant grew at rates comparable to that of wild type under iron-replete conditions but growth of all five mutants was stunted in iron-limiting media. When ferric rhizoferrin was added to the iron-limited media, growth of the figA, figB, figC, and figD mutants was restored to levels similar to those obtained in iron-replete media. However, this exogenously added siderophore could not rescue the figE mutant. When Chrome Azurol S assays were used to measure siderophore production, the figA, figB, and figC mutants were markedly deficient in their ability to synthesize siderophore whereas the figD and figE mutants produced siderophore at levels equivalent to the wild-type parent strain. PMID:18564336

  14. Increased Viral Dissemination in the Brain and Lethality in MCMV-Infected, Dicer-Deficient Neonates

    PubMed Central

    Ostermann, Eleonore; Macquin, Cécile; Krezel, Wojciech; Bahram, Seiamak; Georgel, Philippe

    2015-01-01

    Among Herpesviruses, Human Cytomegalovirus (HCMV or HHV-5) represents a major threat during congenital or neonatal infections, which may lead to encephalitis with serious neurological consequences. However, as opposed to other less prevalent pathogens, the mechanisms and genetic susceptibility factors for CMV encephalitis are poorly understood. This lack of information considerably reduces the prognostic and/or therapeutic possibilities. To easily monitor the effects of genetic defects on brain dissemination following CMV infection we used a recently developed in vivo mouse model based on the neonatal inoculation of a MCMV genetically engineered to express Luciferase. Here, we further validate this protocol for live imaging, and demonstrate increased lethality associated with viral infection and encephalitis in mutant mice lacking Dicer activity. Our data indicate that miRNAs are important players in the control of MCMV pathogenesis and suggest that miRNA-based endothelial functions and integrity are crucial for CMV encephalitis. PMID:25955106

  15. Increased Viral Dissemination in the Brain and Lethality in MCMV-Infected, Dicer-Deficient Neonates.

    PubMed

    Ostermann, Eleonore; Macquin, Cécile; Krezel, Wojciech; Bahram, Seiamak; Georgel, Philippe

    2015-05-01

    Among Herpesviruses, Human Cytomegalovirus (HCMV or HHV-5) represents a major threat during congenital or neonatal infections, which may lead to encephalitis with serious neurological consequences. However, as opposed to other less prevalent pathogens, the mechanisms and genetic susceptibility factors for CMV encephalitis are poorly understood. This lack of information considerably reduces the prognostic and/or therapeutic possibilities. To easily monitor the effects of genetic defects on brain dissemination following CMV infection we used a recently developed in vivo mouse model based on the neonatal inoculation of a MCMV genetically engineered to express Luciferase. Here, we further validate this protocol for live imaging, and demonstrate increased lethality associated with viral infection and encephalitis in mutant mice lacking Dicer activity. Our data indicate that miRNAs are important players in the control of MCMV pathogenesis and suggest that miRNA-based endothelial functions and integrity are crucial for CMV encephalitis. PMID:25955106

  16. Antibody to the E3 glycoprotein protects mice against lethal venezuelan equine encephalitis virus infection.

    PubMed

    Parker, Michael D; Buckley, Marilyn J; Melanson, Vanessa R; Glass, Pamela J; Norwood, David; Hart, Mary Kate

    2010-12-01

    Six monoclonal antibodies were isolated that exhibited specificity for a furin cleavage site deletion mutant (V3526) of Venezuelan equine encephalitis virus (VEEV). These antibodies comprise a single competition group and bound the E3 glycoprotein of VEEV subtype I viruses but failed to bind the E3 glycoprotein of other alphaviruses. These antibodies neutralized V3526 virus infectivity but did not neutralize the parental strain of Trinidad donkey (TrD) VEEV. However, the E3-specific antibodies did inhibit the production of virus from VEEV TrD-infected cells. In addition, passive immunization of mice demonstrated that antibody to the E3 glycoprotein provided protection against lethal VEEV TrD challenge. This is the first recognition of a protective epitope in the E3 glycoprotein. Furthermore, these results indicate that E3 plays a critical role late in the morphogenesis of progeny virus after E3 appears on the surfaces of infected cells. PMID:20926570

  17. Syn-Lethality: An Integrative Knowledge Base of Synthetic Lethality towards Discovery of Selective Anticancer Therapies

    PubMed Central

    Li, Xue-juan; Mishra, Shital K.; Wu, Min; Zhang, Fan

    2014-01-01

    Synthetic lethality (SL) is a novel strategy for anticancer therapies, whereby mutations of two genes will kill a cell but mutation of a single gene will not. Therefore, a cancer-specific mutation combined with a drug-induced mutation, if they have SL interactions, will selectively kill cancer cells. While numerous SL interactions have been identified in yeast, only a few have been known in human. There is a pressing need to systematically discover and understand SL interactions specific to human cancer. In this paper, we present Syn-Lethality, the first integrative knowledge base of SL that is dedicated to human cancer. It integrates experimentally discovered and verified human SL gene pairs into a network, associated with annotations of gene function, pathway, and molecular mechanisms. It also includes yeast SL genes from high-throughput screenings which are mapped to orthologous human genes. Such an integrative knowledge base, organized as a relational database with user interface for searching and network visualization, will greatly expedite the discovery of novel anticancer drug targets based on synthetic lethality interactions. The database can be downloaded as a stand-alone Java application. PMID:24864230

  18. Syn-lethality: an integrative knowledge base of synthetic lethality towards discovery of selective anticancer therapies.

    PubMed

    Li, Xue-juan; Mishra, Shital K; Wu, Min; Zhang, Fan; Zheng, Jie

    2014-01-01

    Synthetic lethality (SL) is a novel strategy for anticancer therapies, whereby mutations of two genes will kill a cell but mutation of a single gene will not. Therefore, a cancer-specific mutation combined with a drug-induced mutation, if they have SL interactions, will selectively kill cancer cells. While numerous SL interactions have been identified in yeast, only a few have been known in human. There is a pressing need to systematically discover and understand SL interactions specific to human cancer. In this paper, we present Syn-Lethality, the first integrative knowledge base of SL that is dedicated to human cancer. It integrates experimentally discovered and verified human SL gene pairs into a network, associated with annotations of gene function, pathway, and molecular mechanisms. It also includes yeast SL genes from high-throughput screenings which are mapped to orthologous human genes. Such an integrative knowledge base, organized as a relational database with user interface for searching and network visualization, will greatly expedite the discovery of novel anticancer drug targets based on synthetic lethality interactions. The database can be downloaded as a stand-alone Java application. PMID:24864230

  19. Chronic Exposure of Corals to Fine Sediments: Lethal and Sub-Lethal Impacts

    PubMed Central

    Flores, Florita; Hoogenboom, Mia O.; Smith, Luke D.; Cooper, Timothy F.; Abrego, David; Negri, Andrew P.

    2012-01-01

    Understanding the sedimentation and turbidity thresholds for corals is critical in assessing the potential impacts of dredging projects in tropical marine systems. In this study, we exposed two species of coral sampled from offshore locations to six levels of total suspended solids (TSS) for 16 weeks in the laboratory, including a 4 week recovery period. Dose-response relationships were developed to quantify the lethal and sub-lethal thresholds of sedimentation and turbidity for the corals. The sediment treatments affected the horizontal foliaceous species (Montipora aequituberculata) more than the upright branching species (Acropora millepora). The lowest sediment treatments that caused full colony mortality were 30 mg l?1 TSS (25 mg cm?2 day?1) for M. aequituberculata and 100 mg l?1 TSS (83 mg cm?2 day?1) for A. millepora after 12 weeks. Coral mortality generally took longer than 4 weeks and was closely related to sediment accumulation on the surface of the corals. While measurements of damage to photosystem II in the symbionts and reductions in lipid content and growth indicated sub-lethal responses in surviving corals, the most reliable predictor of coral mortality in this experiment was long-term sediment accumulation on coral tissue. PMID:22662225

  20. Prediction of lethal and synthetically lethal knock-outs in regulatory networks.

    PubMed

    Boldhaus, Gunnar; Greil, Florian; Klemm, Konstantin

    2013-03-01

    The complex interactions involved in regulation of a cell's function are captured by its interaction graph. More often than not, detailed knowledge about enhancing or suppressive regulatory influences and cooperative effects is lacking and merely the presence or absence of directed interactions is known. Here, we investigate to which extent such reduced information allows to forecast the effect of a knock-out or a combination of knock-outs. Specifically, we ask in how far the lethality of eliminating nodes may be predicted by their network centrality, such as degree and betweenness, without knowing the function of the system. The function is taken as the ability to reproduce a fixed point under a discrete Boolean dynamics. We investigate two types of stochastically generated networks: fully random networks and structures grown with a mechanism of node duplication and subsequent divergence of interactions. On all networks we find that the out-degree is a good predictor of the lethality of a single node knock-out. For knock-outs of node pairs, the fraction of successors shared between the two knocked-out nodes (out-overlap) is a good predictor of synthetic lethality. Out-degree and out-overlap are locally defined and computationally simple centrality measures that provide a predictive power close to the optimal predictor. PMID:22918565

  1. Salmonella typhimurium mutants lacking flagella or motility remain virulent in BALB/c mice.

    PubMed Central

    Lockman, H A; Curtiss, R

    1990-01-01

    Nonmotile flagellated (mot) and nonflagellated (fla) mutants of Salmonella typhimurium LT-2 were isolated from a collection of mutants with random Tn10-insertion mutations. Both classes of mutants were resistant to infection by the flagellotropic bacteriophage chi. The nonflagellated (fla::Tn10) mutants did not react with H antigen-specific antisera and did not possess flagella when examined by electron microscopy, and sheared-cell extracts were devoid of flagellin. The nonmotile (mot::Tn10) mutants reacted with H-specific antisera and expressed paralyzed flagella that were indistinguishable from wild-type flagella. The Tn10 insertions in strain LT-2 were mapped to loci in regions II (flh and mot) and III (fli) of the flagellar genes, and the mutations were transduced into the mouse-virulent S. typhimurium strains SR-11 and SL1344. Lack of motility reduced the ability of S. typhimurium to invade Henle cells in vitro, yet the virulence in mice of the nonmotile mutants of SR-11 and SL1344 was unaffected by the inactivity or loss of flagella. Wild-type SR-11 had a 50% lethal dose (LD50) in BALB/c mice following oral (p.o.) challenge of 2.4 x 10(4) CFU. The p.o. LD50 of the SR-11 fli-8007::Tn10 mutant was 4.5 x 10(4) CFU. The mot-8008::Tn10 mutation in SR-11 conferred paralyzed flagella and increased the p.o. LD50 in mice to 2.2 x 10(5) CFU, but this was not statistically significant. A similar increase in the p.o. LD50 was observed when the SL1344 mot-8008::Tn10 mutant was tested in mice. Wild-type SR-11 and the isogenic nonflagellated and nonmotile mutants were equally virulent in mice challenged via intraperitoneal injection. Images PMID:2152887

  2. Lethal and Pre-Lethal Effects of a Fungal Biopesticide Contribute to Substantial and Rapid Control of Malaria

    E-print Network

    Read, Andrew

    Lethal and Pre-Lethal Effects of a Fungal Biopesticide Contribute to Substantial and Rapid Control ingredients to control the adult mosquitoes that vector malaria. Biopesticides based on the spores that `slow acting' fungal biopesticides are, therefore, incapable of delivering malaria control in real

  3. 76 FR 6054 - Use of Less-Than-Lethal Force: Delegation

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-02-03

    ...less-than-lethal weapons, including those containing chemical agents, may not...less-than-lethal weapons, including chemical agents. (a) The...less-than-lethal weapons, including those containing chemical agents, only...

  4. 28 CFR 552.25 - Use of less-than-lethal weapons, including chemical agents.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... false Use of less-than-lethal weapons, including chemical agents. 552...552.25 Use of less-than-lethal weapons, including chemical agents. (a...authorize the use of less-than-lethal weapons, including those containing...

  5. Evidence of a Dual Function in Fl(2)d, a Gene Needed for Sex-Lethal Expression in Drosophila Melanogaster

    PubMed Central

    Granadino, B.; Juan, A. S.; Santamaria, P.; Sanchez, L.

    1992-01-01

    In Drosophila melanogaster, the female sexual development of the soma and the germline requires the activity of the gene Sxl. The somatic cells need the function of the gene fl(2)d to follow the female developmental pathway, due to its involvement in the female-specific splicing of Sxl RNA. Here we report the analysis of both fl(2)d(1) and fl(2)d(2) mutations: (1) fl(2)d(1) is a temperature-sensitive mutation lethal in females and semilethal in males; (2) fl(2)d(2) is lethal in both sexes; (3) the fl(2)d(1)/fl(2)d(2) constitution is temperature-sensitive and lethal in females, while semilethal in males. The temperature-sensitive period of fl(2)d(1) in females expands the whole development. Sxl(M1) partially suppresses the lethality of fl(2)d(1) homozygous females and that of fl(2)d(1)/fl(2)d(2) constitution, whereas it does not suppress the lethality of fl(2)d(2) homozygous females. The addition of extra Sxl(+) copies does not increase the suppression effect of Sxl(M1). The fl(2)d(1) mutation in homozygosis and the fl(2)d(1)/fl(2)d(2) constitution, but not the fl(2)d(2) in homozygosis, partially suppress the lethality of Sxl(M1) males. This suppression is not prevented by the addition of extra Sxl(+) copies. The semilethality of both fl(2)d(1) and fl(2)d(1)/fl(2)d(2) males, and the lethality of fl(2)d(2) males, is independent of Sxl function. There is no female synergistic lethality between mutations at fl(2)d and neither at sc or da. However, the female synergistic lethality between mutations at Sxl and either sc or da is increased by fl(2)d mutations. We have analyzed the effect of the fl(2)d mutations on the germline development of both females and males. For that purpose, we carried out the clonal analysis of fl(2)d(1) in the germline. In addition, pole cells homozygous for fl(2)d(2) were transplanted into wild-type host embryos, and we checked whether the mutant pole cells were capable of forming functional gametes. The results indicated that fl(2)d mutant germ cells cannot give rise to functional oocytes, while they can form functional sperm. Moreover, Sxl(M1) suppresses the sterility of the fl(2)d(1) homozygous females developing at the permissive temperature. Thus, with respect to the development of the germline the fl(2)d mutations mimic the behavior of loss-of-function mutations at the gene Sxl. Females double heterozygous for fl(2)d and snf(1621) are fully viable and fertile. fl(2)d(2) in heterozygosis partially suppresses the phenotype of female germ cells homozygous for snf(1621); however, this is not the case with the fl(2)d(1) mutation. The fl(2)d mutations partially suppress the phenotype of the female germ cells homozygous for ovo(D1rS1). We conclude that the gene fl(2)d has a dual function: a female-specific function involved in the splicing of Sxl RNA and a non-sex-specific function. Furthermore, the gene fl(2)d is required in the female germline for Sxl expression. PMID:1551580

  6. Sleep restores behavioral plasticity to Drosophila mutants.

    PubMed

    Dissel, Stephane; Angadi, Veena; Kirszenblat, Leonie; Suzuki, Yasuko; Donlea, Jeff; Klose, Markus; Koch, Zachary; English, Denis; Winsky-Sommerer, Raphaelle; van Swinderen, Bruno; Shaw, Paul J

    2015-05-18

    Given the role that sleep plays in modulating plasticity, we hypothesized that increasing sleep would restore memory to canonical memory mutants without specifically rescuing the causal molecular lesion. Sleep was increased using three independent strategies: activating the dorsal fan-shaped body, increasing the expression of Fatty acid binding protein (dFabp), or by administering the GABA-A agonist 4,5,6,7-tetrahydroisoxazolo-[5,4-c]pyridine-3-ol (THIP). Short-term memory (STM) or long-term memory (LTM) was evaluated in rutabaga (rut) and dunce (dnc) mutants using aversive phototaxic suppression and courtship conditioning. Each of the three independent strategies increased sleep and restored memory to rut and dnc mutants. Importantly, inducing sleep also reverses memory defects in a Drosophila model of Alzheimer's disease. Together, these data demonstrate that sleep plays a more fundamental role in modulating behavioral plasticity than previously appreciated and suggest that increasing sleep may benefit patients with certain neurological disorders. PMID:25913403

  7. Connexin mutant embryonic stem cells and human diseases

    PubMed Central

    Nishii, Kiyomasa; Shibata, Yosaburo; Kobayashi, Yasushi

    2014-01-01

    Intercellular communication via gap junctions allows cells within multicellular organisms to share small molecules. The effect of such interactions has been elucidated using mouse gene knockout strategies. Although several mutations in human gap junction-encoding connexin (Cx) have been described, Cx mutants in mice do not always recapitulate the human disease. Among the 20 mouse Cxs, Cx26, Cx43, and Cx45 play roles in early cardiac or placental development, and disruption of the genes results in lethality that hampers further analyses. Embryonic stem cells (ESCs) that lack Cx43 or Cx45 have made analysis feasible in both in vitro differentiated cell cultures and in vivo chimeric tissues. The success of mouse ESCs studies is leading to the use of induced pluripotent stem cells to learn more about the pathogenesis of human Cx diseases. This review summarizes the current status of mouse Cx disruption models and ESC differentiation studies, and discusses their implication for understanding human Cx diseases. PMID:25426253

  8. Gill lesions in the major carp, Labeo rohita exposed to lethal and sublethal concentrations of tannery effluent.

    PubMed

    Dhanapakiam, P; Sampoorani, V; Kavitha, M; Ramasamy, V K; Chandrakala, A; Aruna, K C

    2004-07-01

    The major carp, Labeo rohita were exposed to (0.873%) lethal and sublethal (0.073%) concentrations of tannery effluent for 24h and 40 days respectively under static bioassay condition. The surface architecture of gill revealed severe damages such as : fusion and clumping in the middle and distal parts of the primary lamellae, swelling and deterioration of the cells. The interlamellar space was filled either with hyperplastic epithelial or mucous cells. Secondary lamellae lost their identity and appeared finger like in structure in the lethal concentration and necrosis was observed in the primary and secondary epithelium. Swelling of primary and secondary epithelial cells was evident in sublethal concentration. PMID:15847345

  9. Human cooperation by lethal group competition.

    PubMed

    Egas, Martijn; Kats, Ralph; van der Sar, Xander; Reuben, Ernesto; Sabelis, Maurice W

    2013-01-01

    Why humans are prone to cooperate puzzles biologists, psychologists and economists alike. Between-group conflict has been hypothesized to drive within-group cooperation. However, such conflicts did not have lasting effects in laboratory experiments, because they were about luxury goods, not needed for survival ("looting"). Here, we find within-group cooperation to last when between-group conflict is implemented as "all-out war" (eliminating the weakest groups). Human subjects invested in helping group members to avoid having the lowest collective pay-off, whereas they failed to cooperate in control treatments with random group elimination or with no subdivision in groups. When the game was repeated, experience was found to promote helping. Thus, not within-group interactions alone, not random group elimination, but pay-off-dependent group elimination was found to drive within-group cooperation in our experiment. We suggest that some forms of human cooperation are maintained by multi-level selection: reciprocity within groups and lethal competition among groups acting together. PMID:23459158

  10. Lethal body burdens of polar narcotics: Chlorophenols

    SciTech Connect

    Wezel, A.P. van; Punte, S.S. [Utrecht Univ. (Netherlands). Environmental Chemistry Group; Opperhuizen, A. [Ministry of Transport, Public Works and Water Management, The Hague (Netherlands). National Institute for Coastal and Marine Management

    1995-09-01

    The goal of the present study was to measure in fathead minnow (Pimephales promelas) the lethal body burden (LBB) of three chlorophenols that are known as polar narcotic chemicals. The LBBs of the chlorophenols were compared to LBBs of nonpolar narcotic chemicals to consider if the two classes of narcotic chemicals differ on a body burden level. The LBB of the most acidic chlorophenol was measured at two different levels of pH exposure to determine the influence of the degree of ionization on the magnitude of the LBB. Both n-octanol/water partition coefficients and n-hexane/water partition coefficients of the chlorophenols were determined at different pH levels to consider the influence of ionization on the partition coefficient and to determine the importance of a polar group in the organic phase on the partitioning behavior. Partitioning to n-octanol and n-hexane was used as input in a model to simulate the equilibrium partitioning between hydrophobic and nonhydrophobic and target and nontarget compartments in the fish.

  11. Tumor clone dynamics in lethal prostate cancer

    PubMed Central

    Carreira, Suzanne; Romanel, Alessandro; Goodall, Jane; Grist, Emily; Ferraldeschi, Roberta; Miranda, Susana; Prandi, Davide; Lorente, David; Frenel, Jean-Sebastien; Pezaro, Carmel; Omlin, Aurelius; Rodrigues, Daniel Nava; Flohr, Penelope; Tunariu, Nina; de Bono, Johann S.; Demichelis, Francesca; Attard, Gerhardt

    2015-01-01

    It is unclear whether a single clone metastasizes and remains dominant over the course of lethal prostate cancer. We describe the clonal architectural heterogeneity at different stages of disease progression by sequencing serial plasma and tumor samples from 16 ERG-positive patients. By characterizing the clonality of commonly occurring deletions at 21q22, 8p21, and 10q23, we identified multiple independent clones in metastatic disease that are differentially represented in tissue and circulation. To exemplify the clinical utility of our studies, we then showed a temporal association between clinical progression and emergence of androgen receptor (AR) mutations activated by glucocorticoids in about 20% of patients progressing on abiraterone and prednisolone or dexamethasone. Resistant clones showed a complex dynamic with temporal and spatial heterogeneity, suggesting distinct mechanisms of resistance at different sites that emerged and regressed depending on treatment selection pressure. This introduces a management paradigm requiring sequential monitoring of advanced prostate cancer patients with plasma and tumor biopsies to ensure early discontinuation of agents when they become potential disease drivers. PMID:25232177

  12. Engineered Repressible Lethality for Controlling the Pink Bollworm, a Lepidopteran Pest of Cotton

    PubMed Central

    Morrison, Neil I.; Simmons, Gregory S.; Fu, Guoliang; O’Connell, Sinead; Walker, Adam S.; Dafa’alla, Tarig; Walters, Michelle; Claus, John; Tang, Guolei; Jin, Li; Marubbi, Thea; Epton, Matthew J.; Harris, Claire L.; Staten, Robert T.; Miller, Ernest; Miller, Thomas A.; Alphey, Luke

    2012-01-01

    The sterile insect technique (SIT) is an environmentally friendly method of pest control in which insects are mass-produced, irradiated and released to mate with wild counterparts. SIT has been used to control major pest insects including the pink bollworm (Pectinophora gossypiella Saunders), a global pest of cotton. Transgenic technology has the potential to overcome disadvantages associated with the SIT, such as the damaging effects of radiation on released insects. A method called RIDL (Release of Insects carrying a Dominant Lethal) is designed to circumvent the need to irradiate insects before release. Premature death of insects’ progeny can be engineered to provide an equivalent to sterilisation. Moreover, this trait can be suppressed by the provision of a dietary antidote. In the pink bollworm, we generated transformed strains using different DNA constructs, which showed moderate-to-100% engineered mortality. In permissive conditions, this effect was largely suppressed. Survival data on cotton in field cages indicated that field conditions increase the lethal effect. One strain, called OX3402C, showed highly penetrant and highly repressible lethality, and was tested on host plants where its larvae caused minimal damage before death. These results highlight a potentially valuable insecticide-free tool against pink bollworm, and indicate its potential for development in other lepidopteran pests. PMID:23226548

  13. Lethal bone dysplasia in a fetus with manifestations of atelosteogenesis I and Boomerang dysplasia.

    PubMed

    Greally, M T; Jewett, T; Smith, W L; Penick, G D; Williamson, R A

    1993-11-15

    Atelosteogenesis I (AT-I) and Boomerang dysplasia have been described as separate lethal bone dysplasias. The possibility of a common cause of both conditions was suggested by Hunter and Carpenter (Clin Genet 39(6): 471-480, 1991) in their report of a patient with apparent manifestations of both AT-I and Boomerang dysplasia. We report on a male fetus of 31 weeks gestation whose clinical, radiologic and histologic findings are compared to reported cases of AT-I, Boomerang dysplasia and the patient of Hunter and Carpenter (Clin Genet 39(6): 471-480, 1991). From the documentation of clinical and radiologic findings we demonstrate overlap of AT-I and Boomerang dysplasia in our patient, and, from histologic examination, suggest a defect of cartilage and bone formation as the basic abnormality in this lethal bone dysplasia. PMID:8291529

  14. Consequences and utility of the zinc-dependent metalloprotease activity of anthrax lethal toxin.

    PubMed

    Bromberg-White, Jennifer; Lee, Chih-Shia; Duesbery, Nicholas

    2010-05-01

    Anthrax is caused by the gram-positive bacterium Bacillus anthracis. The pathogenesis of this disease is dependent on the presence of two binary toxins, edema toxin (EdTx) and lethal toxin (LeTx). LeTx, the major virulence factor contributing to anthrax, contains the effector moiety lethal factor (LF), a zinc-dependent metalloprotease specific for targeting mitogen-activated protein kinase kinases. This review will focus on the protease-specific activity and function of LF, and will include a discussion on the implications and consequences of this activity, both in terms of anthrax disease, and how this activity can be exploited to gain insight into other pathologic conditions. PMID:22069624

  15. Lethal and sub lethal effects of the biocide chlorhexidine on aquatic organisms.

    PubMed

    Jesus, Fátima T; Oliveira, Rhaul; Silva, Andreia; Catarino, Ana L; Soares, Amadeu M V M; Nogueira, António J A; Domingues, Inês

    2013-11-01

    Chlorhexidine is among the most used biocides in Europe, however its toxicity to aquatic organisms is scarcely known. The main objective of this study was to assess the lethal and sub lethal effects of chlorhexidine digluconate (ChD) on four aquatic model organisms: the bacteria Vibrio fischeri, the algae Pseudokirchneriella subcapitata, the crustacean Daphnia magna and the embryos of the fish Danio rerio. ChD was very toxic to algae and crustaceans, with a 72 h-EC50 of 62.2 ?g/l and a 48 h-EC50 of 45.0 ?g/l, respectively. Toxicity to fish embryos and the bacteria was lower, with a 96 h-EC50 of 804.0 ?g/l and a 15 min-EC50 of 1,694.0 ?g/l, respectively. Concerning sub lethal effects on D. magna (feeding inhibition) a 6 h-EC50 of 503.7 ?g/l was obtained. In fish, ChD caused developmental abnormalities, namely alterations in the amniotic fluid (48 h-EC20 of 753.6 ?g/l) and early hatching. Moreover, enzymatic biomarkers on fish embryos showed an induction of cholinesterase activity in all ChD tested concentrations (80-900 ?g/l). The catalase activity was also induced at the highest concentration tested (900 ?g/l) whereas no changes were observed for glutathione-S-transferase and lactate dehydrogenase activities. The toxicity of ChD to the algae and crustacean raises concerns about its potential effects in aquatic food webs, since these organisms are in the base of trophic chains, and highlights the need for further studies on ChD toxicity to aquatic organisms. PMID:24026526

  16. Recombination between mutant cauliflower mosaic virus DNAs

    Microsoft Academic Search

    In Seong Choe; Ulrich Melcher; Ken Richards; Genevieve Lebeurier; Richard C Essenberg

    1985-01-01

    A class of mutants of cauliflower mosaic virus (CaMV) DNA was distinguished based on its members' ability to induce symptoms when coinoculated on plants with other CaMV DNAs mutant at a different locus. Three mutants, one each in open reading frame I, III, and VI had this ability. A second class of mutant DNAs did not induce symptoms unless combined

  17. The mutant selection window and antimicrobial resistance

    Microsoft Academic Search

    Karl Drlica

    2003-01-01

    The mutant selection window is an antimicrobial concentration range extending from the minimal concen- tration required to block the growth of wild-type bacteria up to that required to inhibit the growth of the least susceptible, single-step mutant. The upper boundary is also called the mutant prevention concentration (MPC). Placing antimicrobial concentrations inside the window is expected to enrich resistant mutant

  18. Characterization and protective properties of attenuated mutants of Salmonella choleraesuis.

    PubMed Central

    Kelly, S M; Bosecker, B A; Curtiss, R

    1992-01-01

    We have constructed crp::Tn10 and cya::Tn10 Salmonella choleraesuis mutants and their fusaric acid-resistant derivatives with deletions (delta) of the Tn10 and adjacent DNA sequences and found them to be avirulent and able to induce protection against a wild-type challenge in 8-week-old BALB/c mice. Mice survived infection with the crp and cya mutants at doses of more than 7 x 10(3) times the oral (p.o.) 50% lethal dose (LD50) and more than 8 x 10(2) times the intraperitoneal LD50 of the wild-type S. choleraesuis parent. Mice vaccinated with attenuated strains were protected against challenge with more than 1.6 x 10(4) times the p.o. LD50 and more than 80 times the intraperitoneal LD50 of the wild-type virulent S. choleraesuis parent. One deletion mutation isolated in the crp region extends to an adjacent gene(s) that was shown to be associated with avirulence. This gene or operon has been designated cdt (colonization of deep tissues). A delta (crp-cdt)19 strain, when complemented with the wild-type crp gene and promoter on a pBR-derived plasmid, had p.o. LD50 values 10(3) times higher than those for the wild type. A delta cya delta (crp-cdt)19 double mutant was less virulent than and afforded more complete protection against a challenge with the wild-type strain than a delta crp-11 delta cya double mutant or the individual cya, crp, or crp+/cdt mutants. The deletion derivatives exhibited reduced invasion of CHO cells in vitro, and the numbers of the mutants recovered from mouse tissues were less than that of the parent strain. These studies suggest that one or more of the genes involved in cell attachment to and/or invasion of S. choleraesuis may be under catabolite repression. In addition, we describe a new deletion of a gene(s) located in the crp region between cysG and argD that is associated with virulence in S. choleraesuis. Images PMID:1398999

  19. Ectopic Noggin in a Population of Nfatc1 Lineage Endocardial Progenitors Induces Embryonic Lethality

    PubMed Central

    Snider, Paige; Simmons, Olga; Wang, Jian; Hoang, Chinh Q.; Conway, Simon J.

    2015-01-01

    The initial heart is composed of a myocardial tube lined by endocardial cells. The TGF? superfamily is known to play an important role, as BMPs from the myocardium signal to the overlying endocardium to create an environment for EMT. Subsequently, BMP and TGF? signaling pathways synergize to form primitive valves and regulate myocardial growth. In this study, we investigated the requirement of BMP activity by transgenic over-expression of extracellular BMP antagonist Noggin. Using Nfatc1Cre to drive lineage-restricted Noggin within the endocardium, we show that ectopic Noggin arrests cardiac development in E10.5-11 embryos, resulting in small hearts which beat poorly and die by E12.5. This is coupled with hypoplastic endocardial cushions, reduced trabeculation and fewer mature contractile fibrils in mutant hearts. Moreover, Nfatc1Cre-mediated diphtheria toxin fragment-A expression in the endocardium resulted in genetic ablation and a more severe phenotype with lethality at E11 and abnormal linear hearts. Molecular analysis demonstrated that endocardial Noggin resulted in a specific alteration of TGF?/BMP-mediated signal transduction, in that, both Endoglin and ALK1 were downregulated in mutant endocardium. Combined, these results demonstrate the cell-autonomous requirement of the endocardial lineage and function of unaltered BMP levels in facilitating endothelium-cardiomyocyte cross-talk and promoting endocardial cushion formation.

  20. Early embryonic lethality due to targeted inactivation of DNA ligase III.

    PubMed

    Puebla-Osorio, Nahum; Lacey, Devin B; Alt, Frederick W; Zhu, Chengming

    2006-05-01

    DNA ligases catalyze the joining of strand breaks in the phosphodiester backbone of duplex DNA and play essential roles in DNA replication, recombination, repair, and maintenance of genomic integrity. Three mammalian DNA ligase genes have been identified, and their corresponding ligases play distinct roles in DNA metabolism. DNA ligase III is proposed to be involved in the repairing of DNA single-strand breaks, but its precise role has not yet been demonstrated directly. To determine its role in DNA repair, cellular growth, and embryonic development, we introduced targeted interruption of the DNA ligase III (LIG3) gene into the mouse. Mice homozygous for LIG3 disruption showed early embryonic lethality. We found that the mutant embryonic developmental process stops at 8.5 days postcoitum (dpc), and excessive cell death occurs at 9.5 dpc. LIG3 mutant cells have relatively normal XRCC1 levels but elevated sister chromatid exchange. These findings indicate that DNA ligase III is involved in essential DNA repair activities required for early embryonic development and therefore cannot be replaced by other DNA ligases. PMID:16648486

  1. The Mouse X-Linked Developmental Mutant, Tattered, Lies between DXMit55and Xkhand Is Associated with Hyperkeratinization

    Microsoft Academic Search

    Ifeanyi C. Uwechue; Benjamin F. Cooper; Corintha Goble; T. Hacker; Helen J. Blair; David T. Burke; Gail Herman; Yvonne Boyd

    1996-01-01

    The X-linked mouse mutant phenotype, tattered (Td), is associated with prenatal lethality of males and has been mapped previously to the proximal region of the mouse X chromosome. We report here a refined position forTdand demonstrate that it lies in the ?0.9-cM interval betweenDXMit55andXkh.This enables us to predict that the human homologue lies either between CLCN5 and the evolutionary breakpoint

  2. Benomyl-resistant mutant strain of Trichoderma sp. with increased mycoparasitic activity.

    PubMed

    Olejníková, P; Ondrusová, Z; Krystofová, S; Hudecová, D

    2010-01-01

    Application of UV radiation to the strain Trichoderma sp. T-bt (isolated from lignite) resulted in the T-brm mutant which was resistant to the systemic fungicide benomyl. The tub2 gene sequence in the T-brm mutant differed from the parent as well as the collection strain (replacing tyrosine with histidine in the TUB2 protein). Under in vitro conditions this mutant exhibited a higher mycoparasitic activity toward phytopathogenic fungi. PMID:20336512

  3. Benomyl-resistant mutant strain of Trichoderma sp. with increased mycoparasitic activity

    Microsoft Academic Search

    P. Olejníková; Z. Ondrušová; S. Kryštofová; D. Hudecová

    2010-01-01

    Application of UV radiation to the strain Trichoderma sp. T-bt (isolated from lignite) resulted in the T-brm mutant which was resistant to the systemic fungicide benomyl. The\\u000a tub2 gene sequence in the T-brm mutant differed from the parent as well as the collection strain (replacing tyrosine with histidine\\u000a in the TUB2 protein). Under in vitro conditions this mutant exhibited a

  4. Precursors of lethal violence: a death row sample.

    PubMed

    Freedman, D; Hemenway, D

    2000-06-01

    A qualitative methodology based on the standards of criminal defense investigation was used to analyze the social and family histories of 16 men sentenced to death in California. Using a multisource cross-validation methodology, we assessed patterns of impairment, injury and deficit at each of four ecological levels: family, individual, community and social institutions. Investigation documented consistent and pervasive patterns of serious impairment, injury and deficit across the cases and levels. The men share numerous risk factors and few resiliency factors associated with violence. We found family violence in all 16 cases, including severe physical and/or sexual abuse in 14 cases; individual impairments in 16, including 14 with post-traumatic stress disorder, 13 with severe depression and 12 with histories of traumatic brain injury; community isolation and violence in 12; and institutional failure in 15, including 13 cases of severe physical and/or sexual abuse while in foster care or under state youth authority jurisdiction. Appropriate interventions might have made a difference in reducing lethal violence and its precursor conditions. PMID:10798330

  5. Hydrocarbon assimilation and biosurfactant production in Pseudomonas aeruginosa mutants.

    PubMed Central

    Koch, A K; Käppeli, O; Fiechter, A; Reiser, J

    1991-01-01

    We isolated transposon Tn5-GM-induced mutants of Pseudomonas aeruginosa PG201 that were unable to grow in minimal media containing hexadecane as a carbon source. Some of these mutants lacked extracellular rhamnolipids, as shown by measuring the surface and interfacial tensions of the cell culture supernatants. Furthermore, the concentrated culture media of the mutant strains were tested for the presence of rhamnolipids by thin-layer chromatography and for rhamnolipid activities, including hemolysis and growth inhibition of Bacillus subtilis. Mutant 65E12 was unable to produce extracellular rhamnolipids under any of the conditions tested, lacked the capacity to take up 14C-labeled hexadecane, and did not grow in media containing individual alkanes with chain lengths ranging from C12 to C19. However, growth on these alkanes and uptake of [14C]hexadecane were restored when small amounts of purified rhamnolipids were added to the cultures. Mutant 59C7 was unable to grow in media containing hexadecane, nor was it able to take up [14C]hexadecane. The addition of small amounts of rhamnolipids restored growth on alkanes and [14C]hexadecane uptake. In glucose-containing media, however, mutant 59C7 produced rhamnolipids at levels about twice as high as those of the wild-type strain. These results show that rhamnolipids play a major role in hexadecane uptake and utilization by P. aeruginosa. Images PMID:1648079

  6. Transposon insertions causing constitutive sex-lethal activity in Drosophila melanogaster affect Sxl sex-specific transcript splicing

    SciTech Connect

    Berstein, M.; Cline, T.W. [Princeton Univ., Princeton, NJ (United States)]|[Yale Univ., New Haven, CT (United States); Lersch, R.A.; Subrahmanyan, L. [Univ. of California, Berkeley, CA (United States)

    1995-02-01

    Sex-lethal (Sxl) gene products induce female development in Drosophila melanogaster and suppress the transcriptional hyperactivation of X-linked genes responsible for male X-chromosome dosage compensation. Control of Sxl functioning by the dose of X-chromosomes normally ensures that the female-specific functions of this developmental switch gene are only expressed in diplo-X individuals. Although the immediate effect of X-chromosome dose is on Sxl transcription, during most of the life cycle {open_quotes}on{close_quotes} vs. {open_quotes}off{close_quotes} reflects alternative Sxl RNA splicing, with the female (productive) splicing mode maintained by a positive feedback activity of SXL protein on Sxl pre-mRNA splicing. {open_quotes}Male-lethal{close_quotes} (Sxl{sup M}) gain-of-function alleles subvert Sxl control by X-chromosome dose, allowing female Sxl functions to be expressed independent of the positive regulators upstream of Sxl. As a consequence, Sxl{sup M} haplo-X animals (chromosomal males) die because of improper dosage compensation, and Sxl{sup m} chromosomal females survive the otherwise lethal effects of mutations in upstream positive regulators. Transcript analysis of double-mutant male-viable Sxl{sup M} derivatives in which the Sxl{sup M} insertion is cis to loss-of-function mutations, combined with other results reported here, indicates that the constitutive character of these Sxl{sup M} alleles is a consequence of an alteration of the structure of the pre-mRNA that allow some level of female splicing to occur even in the absence of functional SXL protein. Surprisingly, however, most of the constitutive character of Sxl{sup M} alleles appears to depend on the mutant alleles` responsiveness, perhaps greater than wild-type, to the autoregulatory splicing activity of the wild-type SXL proteins they produce. 47 refs., 10 figs., 4 tabs.

  7. Exploiting synthetic lethal interactions for targeted cancer therapy

    E-print Network

    Jiang, Hai

    Emerging data suggests that synthetic lethal interactions between mutated oncogenes/tumor suppressor genes and molecules involved in DNA damage signaling and repair can be therapeutically exploited to preferentially kill ...

  8. Anthrax lethal factor inhibitors as potential countermeasure of the infection.

    PubMed

    Kumar, B V S Suneel; Malik, Siddharth; Grandhi, Pradeep; Dayam, Raveendra; Sarma, J A R P

    2014-01-01

    Anthrax Lethal Factor (LF) is a zinc-dependent metalloprotease, one of the virulence factor of anthrax infection. Three forms of the anthrax infection have been identified: cutaneous (through skin), gastrointestinal (through alimentary tract), and pulmonary (by inhalation of spores). Anthrax toxin is composed of protective antigen (PA), lethal factor (LF), and edema factor (EF). Protective antigen mediates the entry of Lethal Factor/Edema Factor into the cytosol of host cells. Lethal factor (LF) inactivates mitogen-activated protein kinase kinase inducing cell death, and EF is an adenylyl cyclase impairing host defenses. In the past few years, extensive studies are undertaken to design inhibitors targeting LF. The current review focuses on the small molecule inhibitors targeting LF activity and its structure activity relationships (SAR). PMID:25262802

  9. Internal Lethal Concentrations of Halobenzenes with Fish ( Gambusia affinis)

    Microsoft Academic Search

    Yupadee Chaisuksant; Qiming Yu; Des Connell

    1997-01-01

    The internal lethal concentration is a potential measure of toxicity which could be usefully applied in environmental toxicology and risk assessment. Using halobenzenes, which are common environmental contaminants, and represented test compounds, experiments were conducted in aquaria with the mosquitofish (Gambusia affinis). The average internal lethal concentration (ILC50) for four representative halohydrocarbons, 1,4-diBB, 1,2,3-triCB, 1,2,4-triBB, and pentaCB, were consistent with

  10. Production and proteolytic assay of lethal factor from Bacillus anthracis

    Microsoft Academic Search

    Joungmok Kim; Young-Myung Kim; Bon-Sung Koo; Young-Kyu Chae; Moon-Young Yoon

    2003-01-01

    Bacillus anthracis is the causative agent of anthrax. The major virulence factors are a poly-d-glutamic acid capsule and three-protein component exotoxin, protective antigen (PA, 83kDa), lethal factor (LF, 90kDa), and edema factor (EF, 89kDa), respectively. These three proteins individually have no known toxic activities, but in combination with PA form two toxins (lethal toxin or edema toxin), causing different pathogenic

  11. Purified Influenza Virus Nucleoprotein Protects Mice from Lethal Infection

    Microsoft Academic Search

    DAVID C. WRAITH; ANGELA E. VESSEY; BRIGITTE A. ASKONAS

    1987-01-01

    SUMMARY Local administration of nucleoprotein purified from X31 (H3N2) influenza A virus primed for A virus cross-reactive cytotoxic T cells and resulted in substantial protection (75 ~) of mice from a lethal challenge with the heterologous mouse-adapted A\\/PR\\/8\\/34 (H1N1) virus. By following the course of a lethal virus challenge we found that nucleoprotein priming did not prevent virus infection but

  12. Low molecular weight inhibitors of the protease anthrax lethal factor.

    PubMed

    Dalkas, Georgios A; Papakyriakou, Athanasios; Vlamis-Gardikas, Alexios; Spyroulias, Georgios A

    2008-03-01

    Anthrax Lethal Factor (LF) is a zinc-dependent metalloprotease that together with the protective antigen constitute the anthrax lethal toxin, the most prominent virulence factor of the disease anthrax. This review summarizes the current knowledge on anthrax toxicity and defense in relation to LF. Particular emphasis is placed on the structural aspects of LF, the properties of its substrates and the achievements in the design of low molecular weight inhibitors of the catalytic activity of the metalloenzyme. PMID:18336349

  13. Late-acting dominant lethal genetic systems and mosquito control

    PubMed Central

    Phuc, Hoang Kim; Andreasen, Morten H; Burton, Rosemary S; Vass, Céline; Epton, Matthew J; Pape, Gavin; Fu, Guoliang; Condon, Kirsty C; Scaife, Sarah; Donnelly, Christl A; Coleman, Paul G; White-Cooper, Helen; Alphey, Luke

    2007-01-01

    Background Reduction or elimination of vector populations will tend to reduce or eliminate transmission of vector-borne diseases. One potential method for environmentally-friendly, species-specific population control is the Sterile Insect Technique (SIT). SIT has not been widely used against insect disease vectors such as mosquitoes, in part because of various practical difficulties in rearing, sterilization and distribution. Additionally, vector populations with strong density-dependent effects will tend to be resistant to SIT-based control as the population-reducing effect of induced sterility will tend to be offset by reduced density-dependent mortality. Results We investigated by mathematical modeling the effect of manipulating the stage of development at which death occurs (lethal phase) in an SIT program against a density-dependence-limited insect population. We found late-acting lethality to be considerably more effective than early-acting lethality. No such strains of a vector insect have been described, so as a proof-of-principle we constructed a strain of the principal vector of the dengue and yellow fever viruses, Aedes (Stegomyia) aegypti, with the necessary properties of dominant, repressible, highly penetrant, late-acting lethality. Conclusion Conventional SIT induces early-acting (embryonic) lethality, but genetic methods potentially allow the lethal phase to be tailored to the program. For insects with strong density-dependence, we show that lethality after the density-dependent phase would be a considerable improvement over conventional methods. For density-dependent parameters estimated from field data for Aedes aegypti, the critical release ratio for population elimination is modeled to be 27% to 540% greater for early-acting rather than late-acting lethality. Our success in developing a mosquito strain with the key features that the modeling indicated were desirable demonstrates the feasibility of this approach for improved SIT for disease control. PMID:17374148

  14. Mechanism by Which Caffeine Potentiates Lethality of Nitrogen Mustard

    Microsoft Academic Search

    Ching C. Lau; Arthur B. Pardee

    1982-01-01

    Caffeine is synergistic with many DNA-damaging agents in increasing lethality to mammalian cells. The mechanism is not well understood. Our results show that caffeine potentiates the lethality of the nitrogen mustard 2-chloro-N-(2-chloroethyl)-N-methylethanamine (HN2) by inducing damaged cells to undergo mitosis before properly repairing lesions in their DNA. Treatment with low doses of HN2 (0.5 mu M for 1 hr) caused

  15. Functional centrality: detecting lethality of proteins in protein interaction networks.

    PubMed

    Tew, Kar Leong; Li, Xiao-Li; Tan, Soon-Heng

    2007-01-01

    Identifying lethal proteins is important for understanding the intricate mechanism governing life. Researchers have shown that the lethality of a protein can be computed based on its topological position in the protein-protein interaction (PPI) network. Performance of current approaches has been less than satisfactory as the lethality of a protein is a functional characteristic that cannot be determined solely by network topology. Furthermore, a significant number of lethal proteins have low connectivity in the interaction networks but are overlooked by most current methods. Our work reveals that a protein's lethality correlates more strongly with its "functional centrality" than pure topological centrality. We define functional centrality as the topological centrality within a subnetwork of proteins with similar functions. Evaluation experiments on four Saccharomyces cerevisiae PPI datasets showed that NFC performed significantly better than all the other existing computational techniques. Our method was able to detect low connectivity lethal proteins that were previously undetected by conventional methods. The results and an online version of NFC is available at http://lethalproteins.i2r.a-star.edu.sg. PMID:18546514

  16. Protection against Anthrax Lethal Toxin Challenge by Genetic Immunization with a Plasmid Encoding the Lethal Factor Protein

    Microsoft Academic Search

    BRIAN M. PRICE; ADRIANE L. LINER; STEPHEN H. LEPPLA; ALFRED MATECZUN; DARRELL R. GALLOWAY

    2001-01-01

    The ability of genetic vaccination to protect against a lethal challenge of anthrax toxin was evaluated. BALB\\/c mice were immunized via gene gun inoculation with eucaryotic expression vector plasmids encoding either a fragment of the protective antigen (PA) or a fragment of lethal factor (LF). Plasmid pCLF4 contains the N-terminal region (amino acids (aa) 10 to 254) of Bacillus anthracis

  17. Fluoroquinolone and Quinazolinedione Activities against Wild-Type and Gyrase Mutant Strains of Mycobacterium smegmatis?

    PubMed Central

    Malik, Muhammad; Marks, Kevin R.; Mustaev, Arkady; Zhao, Xilin; Chavda, Kalyan; Kerns, Robert J.; Drlica, Karl

    2011-01-01

    Quinazolinediones (diones) are fluoroquinolone-like inhibitors of bacterial gyrase and DNA topoisomerase IV. To assess activity against mycobacteria, C-8-methoxy dione derivatives were compared with cognate fluoroquinolones by using cultured Mycobacterium smegmatis. Diones exhibited higher MIC values than fluoroquinolones; however, MICs for fluoroquinolone-resistant gyrA mutants, normalized to the MIC for wild-type cells, were lower. Addition of a 3-amino group to the 2,4-dione core increased relative activity against mutants, while alteration of the 8-methoxy group to a methyl or of the 2,4-dione core to a 1,3-dione core lowered activity against mutants. A GyrA G89C bacterial variant was strikingly susceptible to most of the diones tested; in contrast, low susceptibility to fluoroquinolones was observed. Many of the bacteriostatic differences between diones and fluoroquinolones were explained by interactions at the N terminus of GyrA helix IV revealed by recently published X-ray structures of drug-topoisomerase-DNA complexes. When lethal activity was normalized to the MIC in order to minimize the effects of drug uptake, efflux, and ternary complex formation, a 3-amino-2,4-dione exhibited killing activity comparable to that of a cognate fluoroquinolone. Surprisingly, the lethal activity of the dione was inhibited less by chloramphenicol than that of the cognate fluoroquinolone. This observation adds the 2,4-dione structural motif to the list of structural features known to impart lethality to fluoroquinolone-like compounds in the absence of protein synthesis, a phenomenon that is not explained by X-ray structures of drug-enzyme-DNA complexes. PMID:21383100

  18. Novel Approach for Comparing the Abilities of Quinolones To Restrict the Emergence of Resistant Mutants during Quinolone Exposure?

    PubMed Central

    Malik, Muhammad; Hoatam, Gerard; Chavda, Kalyan; Kerns, Robert J.; Drlica, Karl

    2010-01-01

    An agar-plate assay was adapted to examine aspects of quinolone structure that restrict the emergence of quinolone-mediated quinolone resistance. When Escherichia coli was applied to agar containing nalidixic acid, the number of quinolone-resistant mutants arising during incubation was decreased by raising the drug concentration and by mutations expected to block the induction of the SOS response (recA, lexA); the mutant number was increased by a mutator mutation (ung). The examination of four related fluoroquinolones then revealed that a C-8 methoxy group and an N-ethyl piperazine substituent at C-7 reduced mutant acquisition more effectively than C-8 H and C-7 C-ethyl piperazine groups. The fluoroquinolone that was most effective at restricting mutant acquisition was the most active when lethal activity was measured on agar plates or in liquid medium (as minimal bactericidal concentration). It also exhibited the lowest ratio of mutant MIC to wild-type MIC when it was tested with a set of isogenic gyrase mutants, and it had a low mutant prevention concentration (MPC) relative to MIC. However, a low MPC was less likely to be important in restricting the induced mutant accumulation because a fluoroquinolone N-ethyl piperazine substituent was more effective than a C-ethyl piperazine substituent at reducing mutant accumulation but was less effective at lowering the MPC. An 8-methoxy-quinazoline-2,4-dione was also effective at restricting the accumulation of resistant mutants on agar. Collectively, these data characterize a simple assay for detection of drug-mediated resistance that is sensitive to the structures of GyrA inhibitors. The assay provides a new method for screening quinolones and quinolone-like molecules that complements MPC-based tests for restricting the emergence of resistance. PMID:19805561

  19. Structural Characteristics of a Photosynthetic Mutant of Euglena gracilis Blocked in Photosystem II 12

    PubMed Central

    Schwelitz, Faye D.; Dilley, R. A.; Crane, F. L.

    1972-01-01

    The techniques of thin sectioning and freeze etching were employed in comparing the chloroplast structure of the wild type and photosynthetic mutant P4 of Euglena gracilis, Z strain. The mutant chloroplasts were characterized by a lack of thylakoid pairing even under high salt conditions. In addition the mutant thylakoids were more varied in size and fewer in number than those of the wild type. No differences between the mutant and wild type were observed in the size and distribution of the particles within the chloroplast membranes seen by the freeze-etching technique. These structural abnormalities do not appear to be correlated per se with the absence of plastoquinone A in the mutant but may be related to a different lipid composition observed in the mutant. Images PMID:16658115

  20. Mutants of Paracoccidioides brasiliensis strain IVIC Pb9 affected in dimorphism.

    PubMed

    San-Blas, F; San-Blas, G

    1992-01-01

    Morphological mutants were isolated after nitrosoguanidine treatment of Paracoccidioides brasiliensis strain IVIC Pb9. Two of these mutants, Pb257 and Pb258, developed a typical mycelia at 23 degrees C, however, the yeast cells which developed at 37 degrees C were indistinguishable from those of the parental strain. A third mutant, strain Pb267, was thermosensitive, grew as yeast-like cells at 23 degrees C, but was unable to survive at 37 degrees C. Morphological observations as well as serological and segregation tests confirmed that the mutant strains originated from P. brasiliensis. Cell wall chemical analyses of the mutant strains grown at 23 degrees C indicated the presence of alkali-soluble, acid-insoluble polysaccharides absent in the parental wild-type strain Pb9 grown under the same conditions. The phenotypes shown by the mutant strains may be related to deficiencies in the proper synthesis of cell wall components of the mycelial phase of this fungus. PMID:1573521

  1. GLYCOLYSIS MUTANTS IN SACCHAROMYCES CEREVISIAE

    Microsoft Academic Search

    SHELLEY B. WEINSTOCK; DAN G. FRAENKEL

    Mutants have been isolated in S. cereuisiae with the phenotype of growth on pyruvate but not on glucose, or growth on rich medium with pyruvate but inhibition by glucose. Screening of mutagenized cultures was either without an enrichment step, or after enrichment using the antibiotic netropsin (YOUNG et al. 1976) or inositol starvation (HENRY, DONAHUE and CULBERTSON 1975). One class

  2. A new mouse mutant, skijumper

    Microsoft Academic Search

    Majid Hafezparast; Simon Ball; Sharon J. Nicholson; Abi Witherden; Demet Arac; Neil Broadway; David Saggerson; Edwin Cooper; Mahmoud Naase; Stephen Gokhale; Patti Quant; Carol Lascelles; Carole Nickols; Cathy S. Baker; Josephine Peters; Joanne E. Martin; Elizabeth M. C. Fisher

    2002-01-01

    Low blood sugar levels are a well-known cause of severe illness and often death in newborn humans, especially those that are small for age. Few of the causes of neonatal hypoglycemia are known, and many remain to be found. We describe a novel mouse mutant, 'skijumper' (skimp), in which pups, despite feeding well, have low levels of glucose and develop

  3. Symbiotic effectiveness of a siderophore overproducing mutant of Mesorhizobium ciceri.

    PubMed

    Raychaudhuri, Nupur; Das, Subrata K; Chakrabartty, Pran K

    2005-01-01

    Mutants of Mesorhizobium ciceri BICC 651 were generated by N-methyl-N'-nitro-N-nitrosoguanidine mutagenesis. Siderophore overproducing mutants were identified on Chrome azurol S agar plates. One of them determined as N15 was examined for symbiotic efficiency and compared to its wild type parent i.e. BICC 651 strain under sterile conditions using Leonard jars in growth chamber and also in pots containing nonsterile alluvial field soil. It was observed that the strain N15 produced about 30% higher number of nodules per plant, fixed 25% more nitrogen per gram of nodule and caused more than 30% increased dry weight of plant shoots. PMID:16209093

  4. Vancomycin minimum inhibitory concentrations and lethality in Staphylococcus aureus bacteremia

    PubMed Central

    Sulla, Felipe; Bussius, Daniel T.; Acquesta, Felipe; Navarini, Alessandra; Sasagawa, Suzethe M.; Mimica, Marcelo J.

    2015-01-01

    Background After the dissemination of penicillin and oxacillin resistance in Staphylococcus aureus, vancomycin-intermediate and vancomycin resistant isolates have been reported. Even between isolates with minimum inhibitory concentrations (MICs) within the susceptible range, some authors have demonstrated that higher MICs correlate with higher lethality. Methods To test this hypothesis in our setting, we compared vancomycin MICs evaluated by two methods and clinical outcomes in hospitalized patients with S. aureus bacteremia. Results We compared lethality in patients infected with isolates that had MICs under or over 2 mg/L. Among patients infected with isolates that had microdilution MICs <2 mg/L, the lethality was 25%; among patients infected with strains that had microdilution MICs ?2 mg/L, 33% died. Among patients infected with isolates that had Etest MICs <2 mg/L, 23% died; in comparison, patients infected with strains that had Etest MICs ?2 mg/L had a lethality of 44%. Conclusion Our results showed a slight tendency of higher lethality when higher MICs were present. However, this difference did not reach statistical significance, possibly due to the relatively small number of patients included in the study. Future prospective studies are needed to further evaluate this correlation and to help clinicians guide antimicrobial therapy. PMID:26097833

  5. Isolation and characterization of Schizosaccharomyces pombe mutants lacking aminopeptidase activity.

    PubMed

    Arbesu, M J; Gascon, S; Suarez-Rendueles, P

    1991-07-01

    A mutant strain of the fission yeast Schizosaccharomyces pombe defective in aminopeptidase I was isolated by screening for lack of activity against the chromogenic substrate lysine-beta-naphthylamide in isolated colonies. Tetrad dissection of sporulated diploids heterozygous for the wild-type and mutant allele resulted in a 2:2 segregation of mutant and wild-type phenotype indicating a single chromosomal gene mutation. Gene dosage experiments indicated that the mutation might reside in the structural gene of aminopeptidase I. No vital consequences of aminopeptidase I deficiency on cell life and sporulation could be detected. However, the enzyme seems to be involved in protein degradation under conditions of nutrient deprivation. PMID:1897317

  6. Neuronal redox imbalance results in altered energy homeostasis and early postnatal lethality.

    PubMed

    Maity-Kumar, Gandhari; Thal, Dietmar R; Baumann, Bernd; Scharffetter-Kochanek, Karin; Wirth, Thomas

    2015-07-01

    Redox imbalance is believed to contribute to the development and progression of several neurodegenerative disorders. Our aim was to develop an animal model that exhibits neuron-specific oxidative stress in the CNS to study the consequences and eventually find clues regarding the pathomechanisms of oxidative insults in neuronal homeostasis. We therefore generated a novel neuron-specific superoxide dismutase 2 (SOD2)-deficient mouse by deleting exon 3 of the SOD2 gene using CamKII? promoter-driven Cre expression. These neuron-specific SOD2 knockout (SOD2(nko)) mice, although born at normal frequencies, died at the age of 4 weeks with critical growth retardation, severe energy failure, and several neurologic phenotypes. In addition, SOD2(nko) mice exhibited severe neuronal alterations such as reactive astrogliosis, neuronal cell cycle inhibition, and induction of apoptosis. JNK activation and stabilization of p53, as a result of reactive oxygen species accumulation, are most likely the inducers of neuronal apoptosis in SOD2(nko) mice. It is remarkable that hypothalamic regulation of glucose metabolism was affected, which in turn induced necrotic brain lesions in SOD2(nko) mice. Taken together, our findings suggest that exclusive deficiency of SOD2 in neurons results in an impaired central regulation of energy homeostasis that leads to persistent hypoglycemia, hypoglycemia-related neuropathology, and an early lethality of the mutant mice.-Maity-Kumar, G., Thal, D. R., Baumann, B., Scharffetter-Kochanek, K., Wirth, T. Neuronal redox imbalance results in altered energy homeostasis and early postnatal lethality. PMID:25829510

  7. Anthrax Lethal Factor Activates K+ Channels To Induce IL-1? Secretion in Macrophages

    PubMed Central

    Thomas, Johnson; Epshtein, Yulia; Chopra, Arun; Ordog, Balazs; Ghassemi, Mahmood; Christman, John W.; Nattel, Stanley; Cook, James L.; Levitan, Irena

    2012-01-01

    Anthrax lethal toxin (LeTx) is a virulence factor of Bacilillus anthracis that is a bivalent toxin, containing lethal factor (LF) and protective Ag proteins, which causes cytotoxicity and altered macrophage function. LeTx exposure results in early K+ efflux from macrophages associated with caspase-1 activation and increased IL-1? release. The mechanism of this toxin-induced K+ efflux is unknown. The goals of the current study were to determine whether LeTx-induced K+ efflux from macrophages is mediated by toxin effects on specific K+ channels and whether altered K+-channel activity is involved in LeTx-induced IL-1? release. Exposure of macrophages to LeTx induced a significant increase in the activities of two types of K+ channels that have been identified in mouse macrophages: Ba2+-sensitive inwardly rectifying K+ (Kir) channels and 4-aminopyridine–sensitive outwardly rectifying voltage-gated K+ (Kv) channels. LeTx enhancement of both Kir and Kv required the proteolytic activity of LF, because exposure of macrophages to a mutant LF-protein (LFE687C) combined with protective Ag protein had no effect on the currents. Furthermore, blocking Kir and Kv channels significantly decreased LeTx-induced release of IL-1?. In addition, retroviral transduction of macrophages with wild-type Kir enhanced LeTx-induced release of IL-1?, whereas transduction of dominant-negative Kir blocked LeTx-induced release of IL-1?. Activation of caspase-1 was not required for LeTx-induced activation of either of the K+ channels. These data indicate that a major mechanism through which LeTx stimulates macrophages to release IL-1? involves an LF-protease effect that enhances Kir and Kv channel function during toxin stimulation. PMID:21421849

  8. Structure and novel functional mechanism of Drosophila SNF in sex-lethal splicing.

    PubMed

    Hu, Jicheng; Cui, Gaofeng; Li, Congmin; Liu, Cong; Shang, Erchang; Lai, Luhua; Jin, Changwen; Wang, Jiwu; Xia, Bin

    2009-01-01

    Sans-fille (SNF) is the Drosophila homologue of mammalian general splicing factors U1A and U2B'', and it is essential in Drosophila sex determination. We found that, besides its ability to bind U1 snRNA, SNF can also bind polyuridine RNA tracts flanking the male-specific exon of the master switch gene Sex-lethal (Sxl) pre-mRNA specifically, similar to Sex-lethal protein (SXL). The polyuridine RNA binding enables SNF directly inhibit Sxl exon 3 splicing, as the dominant negative mutant SNF(1621) binds U1 snRNA but not polyuridine RNA. Unlike U1A, both RNA recognition motifs (RRMs) of SNF can recognize polyuridine RNA tracts independently, even though SNF and U1A share very high sequence identity and overall structure similarity. As SNF RRM1 tends to self-associate on the opposite side of the RNA binding surface, it is possible for SNF to bridge the formation of super-complexes between two introns flanking Sxl exon 3 or between a intron and U1 snRNP, which serves the molecular basis for SNF to directly regulate Sxl splicing. Taken together, a new functional model for SNF in Drosophila sex determination is proposed. The key of the new model is that SXL and SNF function similarly in promoting Sxl male-specific exon skipping with SNF being an auxiliary or backup to SXL, and it is the combined dose of SXL and SNF governs Drosophila sex determination. PMID:19727396

  9. Dystrophin deficiency causes lethal muscle hypertrophy in cats.

    PubMed

    Gaschen, F P; Hoffman, E P; Gorospe, J R; Uhl, E W; Senior, D F; Cardinet, G H; Pearce, L K

    1992-07-01

    Two 5-month-old male Domestic Shorthair littermates showed general skeletal muscle hypertrophy, multifocal submucosal lingual calcification with lingual enlargement, and excessive salivation. Both cats had a reduced level of activity, walked with a stiff gait, and tended to "bunny hop" when they ran. These clinical features were similar to those of previously reported dystrophin-deficient cats. Using multiple dystrophin antibodies, we found that the cats described in this report also showed marked dystrophin deficiency. The histopathology was remarkable for hypertrophy and splitting of fibers, and progressive accumulation of calcium deposits within the muscle. There was little or no endomysial fibrosis at 2 years of age. The natural history of dystrophin-deficiency in cats has not been described: both previous cats had been euthanized at 2 years of age prior to experiencing any life-threatening problems. At 6 months of age, one of the new cats developed megaesophagus because of severe progressive hypertrophy of the diaphragmatic muscles. The diaphragm completely occluded the esophagus, and the cat was euthanized for humane reasons. The second cat remained in good condition until age 18 months when it developed acute renal failure attributed to severe prolonged dehydration and hyperosmolality. The cat recovered after receiving supportive treatment but was unable to maintain fluid homeostasis. The insufficient water intake was attributed to glossal hypertrophy and dysfunction. At age 2 years, the cat received regular subcutaneous injections of low-sodium fluids to maintain proper hydration. The clinical consequence of dystrophin deficiency in cats is lethal muscle hypertrophy. We have called the feline disease "hypertrophic feline muscular dystrophy" (HFMD). PMID:1506854

  10. A Sall4 mutant mouse model useful for studying the role of Sall4 in early embryonic development and organogenesis.

    PubMed

    Warren, Madhuri; Wang, Wei; Spiden, Sarah; Chen-Murchie, Dongrong; Tannahill, David; Steel, Karen P; Bradley, Allan

    2007-01-01

    SALL4 is a homologue of the Drosophila homeotic gene spalt, a zinc finger transcription factor, required for inner cell mass proliferation in early embryonic development. It also interacts with other transcription factors to control the development of the anorectal region, kidney, heart, limbs, and brain. Truncating mutations in SALL4 cause Okihiro syndrome, manifest as Duane anomaly, radial ray defects and sensorineural and conductive deafness. We report the characterization of a novel murine Sall4 null allele created by bacterial recombineering in ES cells. Homozygous mutant mice exhibit early embryonic lethality. Heterozygous mutant mice recapitulate phenotypic features of Okihiro syndrome including deafness, lower anogenital tract abnormalities, renal hypoplasia, anencephaly, Hirschprung's disease, and skeletal defects. This phenotype shows important differences in cardiac and ear manifestations to previously characterized Sall4 mutant alleles and should prove useful for the investigation of the influence of modifier alleles and protein interactions on the transcriptional regulatory function of Sall4. PMID:17216607

  11. Branchio-oculo-facial syndrome: a three generational family with markedly variable phenotype including neonatal lethality.

    PubMed

    Titheradge, Hannah L; Patel, Chirag; Ragge, Nicola K

    2015-01-01

    Branchio-oculo-facial syndrome (BOFS) is a rare autosomal dominant condition with variable expressivity, caused by mutations in the TFAP2A gene. We report a three generational family with four affected individuals. The consultand has typical features of BOFS including infra-auricular skin nodules, coloboma, lacrimal duct atresia, cleft lip, conductive hearing loss and typical facial appearance. She also exhibited a rare feature of preaxial polydactyly. Her brother had a lethal phenotype with multiorgan failure. We also report a novel variant in TFAP2A gene. This family highlights the variable severity of BOFS and, therefore, the importance of informed genetic counselling in families with BOFS. PMID:25325185

  12. Lethal effects of short-wavelength visible light on insects

    PubMed Central

    Hori, Masatoshi; Shibuya, Kazuki; Sato, Mitsunari; Saito, Yoshino

    2014-01-01

    We investigated the lethal effects of visible light on insects by using light-emitting diodes (LEDs). The toxic effects of ultraviolet (UV) light, particularly shortwave (i.e., UVB and UVC) light, on organisms are well known. However, the effects of irradiation with visible light remain unclear, although shorter wavelengths are known to be more lethal. Irradiation with visible light is not thought to cause mortality in complex animals including insects. Here, however, we found that irradiation with short-wavelength visible (blue) light killed eggs, larvae, pupae, and adults of Drosophila melanogaster. Blue light was also lethal to mosquitoes and flour beetles, but the effective wavelength at which mortality occurred differed among the insect species. Our findings suggest that highly toxic wavelengths of visible light are species-specific in insects, and that shorter wavelengths are not always more toxic. For some animals, such as insects, blue light is more harmful than UV light. PMID:25488603

  13. The effects of anthrax lethal toxin on host barrier function.

    PubMed

    Xie, Tao; Auth, Roger D; Frucht, David M

    2011-06-01

    The pathological actions of anthrax toxin require the activities of its edema factor (EF) and lethal factor (LF) enzyme components, which gain intracellular access via its receptor-binding component, protective antigen (PA). LF is a metalloproteinase with specificity for selected mitogen-activated protein kinase kinases (MKKs), but its activity is not directly lethal to many types of primary and transformed cells in vitro. Nevertheless, in vivo treatment of several animal species with the combination of LF and PA (termed lethal toxin or LT) leads to morbidity and mortality, suggesting that LT-dependent toxicity is mediated by cellular interactions between host cells. Decades of research have revealed that a central hallmark of this toxicity is the disruption of key cellular barriers required to maintain homeostasis. This review will focus on the current understanding of the effects of LT on barrier function, highlighting recent progress in establishing the molecular mechanisms underlying these effects. PMID:22069727

  14. STUDIES ON A NONDORMANT SUNFLOWER MUTANT

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An unexpected sunflower mutant resulting from an interspecific cross of the wild perennial Helianthus divaricatus with cultivated HA 89 was identified. In this mutant, dormancy is not induced in the developing embryo. Instead, developing seeds of the mutant sunflower begin to germinate in the head a...

  15. Expanded metabolic reconstruction of Helicobacter pylori (iIT341 GSM/GPR): an in silico genome-scale characterization of single- and double-deletion mutants.

    PubMed

    Thiele, Ines; Vo, Thuy D; Price, Nathan D; Palsson, Bernhard Ø

    2005-08-01

    Helicobacter pylori is a human gastric pathogen infecting almost half of the world population. Herein, we present an updated version of the metabolic reconstruction of H. pylori strain 26695 based on the revised genome annotation and new experimental data. This reconstruction, iIT341 GSM/GPR, represents a detailed review of the current literature about H. pylori as it integrates biochemical and genomic data in a comprehensive framework. In total, it accounts for 341 metabolic genes, 476 intracellular reactions, 78 exchange reactions, and 485 metabolites. Novel features of iIT341 GSM/GPR include (i) gene-protein-reaction associations, (ii) elementally and charge-balanced reactions, (iii) more accurate descriptions of isoprenoid and lipopolysaccharide metabolism, and (iv) quantitative assessments of the supporting data for each reaction. This metabolic reconstruction was used to carry out in silico deletion studies to identify essential and conditionally essential genes in H. pylori. A total of 128 essential and 75 conditionally essential metabolic genes were identified. Predicted growth phenotypes of single knockouts were validated using published experimental data. In addition, in silico double-deletion studies identified a total of 47 synthetic lethal mutants involving 67 different metabolic genes in rich medium. PMID:16077130

  16. Approaches to Identifying Synthetic Lethal Interactions in Cancer

    PubMed Central

    Thompson, Jordan M.; Nguyen, Quy H.; Singh, Manpreet; Razorenova, Olga V.

    2015-01-01

    Targeting synthetic lethal interactions is a promising new therapeutic approach to exploit specific changes that occur within cancer cells. Multiple approaches to investigate these interactions have been developed and successfully implemented, including chemical, siRNA, shRNA, and CRISPR library screens. Genome-wide computational approaches, such as DAISY, also have been successful in predicting synthetic lethal interactions from both cancer cell lines and patient samples. Each approach has its advantages and disadvantages that need to be considered depending on the cancer type and its molecular alterations. This review discusses these approaches and examines case studies that highlight their use.

  17. Advantages of less-tech, less-than-lethal technologies

    NASA Astrophysics Data System (ADS)

    Marts, Donna J.; Overlin, Trudy K.

    1995-05-01

    This paper illustrates the advantages of developing less-tech technologies by reporting on two less-tech, less-than-lethal prototype law enforcement tools developed at the Idaho National Engineering Laboratory. The devices were developed for the National Institute of Justice, less- than-lethal weapons program: 1) an air bag restraint device for use in restraining suspects who become violent during transport in patrol vehicles, and 2) a retractable spiked barrier strip for stopping fleeing vehicles during high-speed pursuit. The success of both projects relied on developing design requirements in conjunction with the actual users of the devices.

  18. The Generation and Genetic Analysis of Suppressors of Lethal Mutations in the Caenorhabditis Elegans Rol-3(v) Gene

    PubMed Central

    Barbazuk, W. B.; Johnsen, R. C.; Baillie, D. L.

    1994-01-01

    The Caenorhabditis elegans rol-3(e754) mutation is a member of a general glass of mutations affecting gross morphology, presumably through disruption of the nematode cuticle. Adult worms homozygous for rol-3(e754) exhibit rotation about their long axis associated with a left-hand twisted cuticle, musculature, gut and ventral nerve cord. Our laboratory previously isolated 12 recessive lethal alleles of rol-3. All these lethal alleles cause an arrest in development at either early or mid-larval stages, suggesting that the rol-3 gene product performs an essential developmental function. Furthermore, through the use of the heterochronic mutants lin-14 and lin-29, we have established that the expression of rol-3(e754)'s adult specific visible function is not dependent on the presence of an adult cuticle. In an attempt to understand rol-3's developmental role we sought to identify other genes whose products interact with that of rol-3. Toward this end, we generated eight EMS induced and two gamma irradiation-induced recessive suppressors of the temperature sensitive (ts) mid-larval lethal phenotype of rol-3(s1040ts). These suppressors define two complementation groups srl-1 II and srl-2 III; and, while they suppress the rol-3(s1040) lethality, they do not suppress the adult specific visible rolling phenotype. Furthermore, there is a complex genetic interaction between srl-2 and srl-1 such that srl-2(s2506) fails to complement all srl alleles tested. These results suggest that srl-1 and srl-2 may share a common function and, thus, possibly constitute members of the same gene family. Mutations in both srl-1 and srl-2 produce no obvious hermaphrodite phenotypes in the absence of rol-3(s1040ts); however, males homozygous for either srl-1 or srl-2 display aberrant tail morphology. We present evidence suggesting that the members of srl-2 are not allele specific with respect to their suppression of rol-3 lethality, and that rol-3 may act in some way to influence proper posterior morphogenesis. Finally, based on our genetic analysis of rol-3 and the srl mutations, we present a model whereby the wild-type products of the srl loci act in a concerted manner to negatively regulate the rol-3 gene. PMID:8138151

  19. Selection of Extranuclear Mutants of NEUROSPORA CRASSA

    PubMed Central

    Rosenberg, Emiko; Mora, Christina; Edwards, David L.

    1976-01-01

    A procedure is described that produces primarily extranuclear mutants of Neurospora crassa. An analysis of five mutants, [ cni-3], [cni-4], [rsp-2], [rsp-3], [rsp-4 ] is presented. All five mutants segregate in an extranuclear manner. They can be assorted into two classes based on their respiratory properties: (1) those with cyanide-insensitive respiration (cni); (2) those with slow respiration (rsp). All of the mutants are female sterile. The respiratory trait can be placed in different nuclear backgrounds by heterokaryotic transfer. The abnormal respiratory traits are observed in mitochondria isolated from the mutants and it is likely that the mutations are in mitochondrial DNA. PMID:131734

  20. Mutants resistant to anti-microtubule herbicides map to a locus on the uni linkage group in Chlamydomonas reinhardtii

    SciTech Connect

    James, S.W.; Ranum, L.P.W.; Silflow, C.D.; Lefebvre, P.A.

    1988-01-01

    The authors have used genetic analysis to study the mode of action of two anti-microtubule herbicides, amiprophos-methyl (APM) and oryzaline (ORY). Over 200 resistant mutants were selected by growth on APM- or ORY-containing plates. The 21 independently isolated mutants examined in this study are 3- to 8-fold resistant to APM and are strongly cross-resistant to ORY and butamiphos, a close analog of APM. Two Mendelian genes, apm1 and apm2, are defined by linkage and complementation analysis. There are 20 alleles of apm1 and one temperature-sensitive lethal (33/sup 0/) allele of apm2. Mapping by two-factor crosses places apm1 6.5 cM centromere proximal to uni1 and within 4 cM of pf7 on the uni linkage group, a genetically circular linkage group comprising genes which affect flagellar assembly or function; apm2 maps near the centromere of linkage group VIII. Allele-specific synthetic lethality is observed in crosses between amp2 and alleles of apm1. Also, self crosses of apm2 are zygotic lethal, whereas crosses of nine apm1 alleles inter se result in normal germination and tetrad viability. The mutants are recessive to their wild-type alleles but doubly heterozygous diploids (apm1 +/+ apm2) made with apm2 and any of 15 apm1 alleles display partial intergenic noncomplementation, expressed as intermediate resistance. Diploids homozygous for mutant alleles of apm1 are 4-6-fold resistant to APM and ORY; diploids homozygous for apm2 are ts/sup -/ and 2-fold resistant to the herbicides. From the results described the authors suggest that the gene products of apm1 and apm2 may interact directly or function in the same structure or process.

  1. Molecular genetics of Drosophila alpha-actinin: mutant alleles disrupt Z disc integrity and muscle insertions

    PubMed Central

    1990-01-01

    We have isolated a Drosophila melanogaster alpha-actinin gene and partially characterized several mutant alleles. The Drosophila protein sequence is very similar (68% identity) to those of chicken alpha- actinin isoforms, but less closely related (30% identity) to Dictyostelium alpha-actinin. The gene is within subdivision 2C of the X chromosome, coincident with 15 lethal (1)2Cb mutations. At least four alleles, l(1)2Cb1, l(1)2Cb2, l(1)2Cb4, and l(1)2Cb5 are interrupted by rearrangement breakpoints and must be null. In all four cases, hemizygous mutants complete embryogenesis and do not die until the second day of larval growth, signifying that either the role of alpha- actinin in nonmuscle cells is redundant or that a distinct and only distantly related gene encodes the non-muscle isoform. Allelic but less severely affected fliA mutants are apparently due to point mutations, and develop into adults having thoracic muscle abnormalities. EM of mutant muscles reveals that Z discs and myofibrillar attachments are disrupted, whereas epithelial "tendon" cells are less affected. We discuss these phenotypes in the light of presumed in vivo alpha-actinin functions. PMID:2112549

  2. The legwd mutant uncovers the role of starch phosphorylation in pollen development and germination in tomato.

    PubMed

    Nashilevitz, Shai; Melamed-Bessudo, Cathy; Aharoni, Asaph; Kossmann, Jens; Wolf, Shmuel; Levy, Avraham A

    2009-01-01

    Starches extracted from most plant species are phosphorylated. alpha-Glucan water dikinase (GWD) is a key enzyme that controls the phosphate content of starch. In the absence of its activity starch degradation is impaired, leading to a starch excess phenotype in Arabidopsis and in potato leaves, and to reduced cold sweetening in potato tubers. Here, we characterized a transposon insertion (legwd::Ds) in the tomato GWD (LeGWD) gene that caused male gametophytic lethality. The mutant pollen had a starch excess phenotype that was associated with a reduction in pollen germination. SEM and TEM analyses indicated mild shrinking of the pollen grains and the accumulation of large starch granules inside the plastids. The level of soluble sugars was reduced by 1.8-fold in mutant pollen grains. Overall, the transmission of the mutant allele was only 0.4% in the male, whereas it was normal in the female. Additional mutant alleles, obtained through transposon excision, showed the same phenotypes as legwd::Ds. Moreover, pollen germination could be restored, and the starch excess phenotype could be abolished in lines expressing the potato GWD homolog (StGWD) under a pollen-specific promoter. In these lines, where fertility was restored, homozygous plants for legwd::Ds were isolated, and showed the starch excess phenotype in the leaves. Overall, our results demonstrate the importance of starch phosphorylation and breakdown for pollen germination, and open up the prospect for analyzing the role of starch metabolism in leaves and fruits. PMID:18764922

  3. Burkholderia pseudomallei Known Siderophores and Hemin Uptake Are Dispensable for Lethal Murine Melioidosis

    PubMed Central

    Kvitko, Brian H.; Goodyear, Andrew; Propst, Katie L.; Dow, Steven W.; Schweizer, Herbert P.

    2012-01-01

    Burkholderia pseudomallei is a mostly saprophytic bacterium, but can infect humans where it causes the difficult-to-manage disease melioidosis. Even with proper diagnosis and prompt therapeutic interventions mortality rates still range from >20% in Northern Australia to over 40% in Thailand. Surprisingly little is yet known about how B. pseudomallei infects, invades and survives within its hosts, and virtually nothing is known about the contribution of critical nutrients such as iron to the bacterium's pathogenesis. It was previously assumed that B. pseudomallei used iron-acquisition systems commonly found in other bacteria, for example siderophores. However, our previous discovery of a clinical isolate carrying a large chromosomal deletion missing the entire malleobactin gene cluster encoding the bacterium's major high-affinity siderophore while still being fully virulent in a murine melioidosis model suggested that other iron-acquisition systems might make contributions to virulence. Here, we deleted the major siderophore malleobactin (mba) and pyochelin (pch) gene clusters in strain 1710b and revealed a residual siderophore activity which was unrelated to other known Burkholderia siderophores such as cepabactin and cepaciachelin, and not due to increased secretion of chelators such as citrate. Deletion of the two hemin uptake loci, hmu and hem, showed that Hmu is required for utilization of hemin and hemoglobin and that Hem cannot complement a Hmu deficiency. Prolonged incubation of a hmu hem mutant in hemoglobin-containing minimal medium yielded variants able to utilize hemoglobin and hemin suggesting alternate pathways for utilization of these two host iron sources. Lactoferrin utilization was dependent on malleobactin, but not pyochelin synthesis and/or uptake. A mba pch hmu hem quadruple mutant could use ferritin as an iron source and upon intranasal infection was lethal in an acute murine melioidosis model. These data suggest that B. pseudomallei may employ a novel ferritin-iron acquisition pathway as a means to sustain in vivo growth. PMID:22745846

  4. 5-Azacytidine Can Induce Lethal Mutagenesis in Human Immunodeficiency Virus Type 1? †

    PubMed Central

    Dapp, Michael J.; Clouser, Christine L.; Patterson, Steven; Mansky, Louis M.

    2009-01-01

    Ribonucleosides inhibit human immunodeficiency virus type 1 (HIV-1) replication by mechanisms that have not been fully elucidated. Here, we report the antiviral mechanism for the ribonucleoside analog 5-azacytidine (5-AZC). We hypothesized that the anti-HIV-1 activity of 5-AZC was due to an increase in the HIV-1 mutation rate following its incorporation into viral RNA during transcription. However, we demonstrate that 5-AZC's primary antiviral activity can be attributed to its effect on the early phase of HIV-1 replication. Furthermore, the antiviral activity was associated with an increase in the frequency of viral mutants, suggesting that 5-AZC's primary target is reverse transcription. Sequencing analysis showed an enrichment in G-to-C transversion mutations and further supports the idea that reverse transcription is an antiviral target of 5-AZC. These results indicate that 5-AZC is incorporated into viral DNA following reduction to 5-aza-2?-deoxycytidine. Incorporation into the viral DNA leads to an increase in mutant frequency that is consistent with lethal mutagenesis during reverse transcription as the primary antiviral mechanism of 5-AZC. Antiviral activity and increased mutation frequency were also associated with the late phase of HIV-1 replication; however, 5-AZC's effect on the late phase was less robust. These results reveal that the primary antiviral mechanism of 5-AZC can be attributed to its ability to increase the HIV-1 mutation frequency through viral-DNA incorporation during reverse transcription. Our observations indicate that 5-AZC can affect two steps in HIV-1 replication (i.e., transcription and reverse transcription) but that its primary antiviral activity is due to incorporation during reverse transcription. PMID:19726509

  5. Anthrax Toxin Receptor 2Dependent Lethal Toxin Killing In Vivo

    E-print Network

    Sejnowski, Terrence J.

    Anthrax Toxin Receptor 2­Dependent Lethal Toxin Killing In Vivo Heather M. Scobie1,2 , Darran J Jolla, California, United States of America Anthrax toxin receptors 1 and 2 (ANTXR1 and ANTXR2) have by residue D683 of the protective antigen (PA) subunit of anthrax toxin. The receptor-bound metal ion and PA

  6. Bureaucracy, Safety and Software: a potentially lethal cocktail

    E-print Network

    Hatton, Les

    Bureaucracy, Safety and Software: a potentially lethal cocktail Les Hatton CISM, University of software controlled safety critical systems. It observes that the rapid growth of bureaucracy in society of such bureaucracy are generally mitigated because the rules naturally devolve from the exercise of the scientific

  7. The Prevalence, Lethality and Intent of Suicide Attempts among Adolescents.

    ERIC Educational Resources Information Center

    Andrews, Judy A.; Lewinsohn, Peter M.

    Although suicide is the second leading cause of death among adolescents in the United States, little is known about the prevalence or characteristics of suicide attempts among adolescents. Data from 1,710 adolescents attending 9 high schools in 5 communities were examined to determine the prevalence of suicide attempts and the lethality and intent…

  8. Regulation of apoptosis by lethal cytokines in human mesothelial cells

    Microsoft Academic Search

    Marina Penélope Catalan; Dolores Subirá; Ana Reyero; Rafael Selgas; Arturo Ortiz-Gonzalez; Jesús Egido; Alberto Ortiz

    2003-01-01

    Regulation of apoptosis by lethal cytokines in human mesothelial cells.BackgroundDysregulation of peritoneal cell death may contribute to the complications of peritoneal dialysis (PD). Chronic peritoneal dialysis and acute peritonitis are both associated with loss of mesothelial cells. In addition, acute peritonitis is characterized by sudden changes in the number of peritoneal leukocytes. However, the factors regulating peritoneal cell survival are

  9. ACUTE LETHALITY OF COPPER, CADMIUM, AND ZINC TO NORTHERN SQUAWFISH

    EPA Science Inventory

    Flow-through acute toxicity tests on juvenile northern squawfish (Ptychocheilus oregonensis) were conducted with copper, cadmium, and zinc. The 96-hour median lethal concentrations were 18 micrograms/liter for copper, 1,104 micrograms/liter for cadmium, and 3,693 micrograms/liter...

  10. Hyperinsulinaemia: A prospective risk factor for lethal clinical prostate cancer

    Microsoft Academic Search

    Jan Hammarsten; Benkt Högstedt

    2005-01-01

    Previous studies have suggested that hyperinsulinaemia and other components of metabolic syndrome are risk factors for clinical prostate cancer. This prospective study tested the hypothesis that hyperinsulinaemia and other components of metabolic syndrome are risk factors for lethal clinical prostate cancer. The clinical, haemodynamic, anthropometric, metabolic and insulin profile at baseline in men who had died from clinical prostate cancer

  11. Prison Inmate Characteristics and Suicide Attempt Lethality: An Exploratory Study

    Microsoft Academic Search

    Philip R. Magaletta; Marc W. Patry; Ben Wheat; Jeffery Bates

    2008-01-01

    Working with suicidal inmates is among the most demanding elements of clinical practice in corrections, yet few studies regarding the characteristics of prison inmate suicide attempters or their attempts exist. This represents a significant gap as the method of attempt, the prison context, and the resulting lethality of these incidents may be different from attempts made outside of prison. This

  12. HSP70 Protects against TNF-Induced Lethal Inflammatory Shock

    Microsoft Academic Search

    Wim Van Molle; Ben Wielockx; Tina Mahieu; Masuhiro Takada; Takahide Taniguchi; Kenji Sekikawa; Claude Libert

    2002-01-01

    The heat shock (HS) response is a universal response activated after exposure to various stimuli. The major HS protein (HSP) is the 72 kDa HSP70 with strong homology in different eukaryotic species. We demonstrate that HS treatment of mice leads to a strong induction of HSP70 in several organs and confers significant protection against lethality induced by tumor necrosis factor

  13. Help-Seeking Behavior Prior to Nearly Lethal Suicide Attempts.

    ERIC Educational Resources Information Center

    Barnes, Lauren Seymour; Ikeda, Robin M.; Kresnow, Marcie-jo

    2002-01-01

    The association between help-seeking and nearly lethal suicide attempts was evaluated using data from a population-based, case-control study. Measures of help-seeking included type of consultant contacted, and whether suicide was discussed. Findings suggest efforts to better understand the role of help-seeking in suicide prevention deserves…

  14. Lethal Autonomous Systems and the Plight of the Noncombatant

    E-print Network

    Lethal Autonomous Systems and the Plight of the Non­combatant by Ronald Arkin (Georgia Institute gathering, surveil­ lance, reconnaissance, target acquisi­ tion, designation and engagement ca­ pabilities­ manisation of the enemy through the use of derogatory names and epithets; poorly trained or inexperienced

  15. Science or slaughter: need for lethal sampling of sharks.

    PubMed

    Heupel, M R; Simpfendorfer, C A

    2010-10-01

    General consensus among scientists, commercial interests, and the public regarding the status of shark populations is leading to an increasing need for the scientific community to provide information to help guide effective management and conservation actions. Experience from other marine vertebrate taxa suggests that public, political, and media pressures will play an increasingly important part in setting research, management, and conservation priorities. We examined the potential implications of nonscientific influences on shark research. In particular, we considered whether lethal research sampling of sharks is justified. Although lethal sampling comes at a cost to a population, especially for threatened species, the conservation benefits from well-designed studies provide essential data that cannot be collected currently in any other way. Methods that enable nonlethal collection of life-history data on sharks are being developed (e.g., use of blood samples to detect maturity), but in the near future they will not provide widespread or significant benefits. Development of these techniques needs to continue, as does the way in which scientists coordinate their use of material collected during lethal sampling. For almost half of the known shark species there are insufficient data to determine their population status; thus, there is an ongoing need for further collection of scientific data to ensure all shark populations have a future. Shark populations will benefit most when decisions about the use of lethal sampling are made on the basis of scientific evidence that is free from individual, political, public, and media pressures. PMID:20337690

  16. Small Molecule Inhibitors of Anthrax Lethal Factor Toxin

    PubMed Central

    Williams, John D.; Khan, Atiyya R.; Cardinale, Steven C.; Butler, Michelle M.; Bowlin, Terry L.; Peet, Norton P.

    2014-01-01

    This manuscript describes the preparation of new small molecule inhibitors of Bacillus anthracis lethal factor. Our starting point was the symmetrical, bis-quinolinyl compound 1 (NSC 12155). Optimization of one half of this molecule led to new LF inhibitors that were desymmetrized to afford more drug-like compounds. PMID:24290062

  17. An overview of the future of non-lethal weapons.

    PubMed

    Alexander, J B

    2001-01-01

    During the past decade, vast changes have occurred in the geopolitical landscape and the nature of the types of conflicts in which technologically developed countries have been involved. While the threat of conventional war remains, forces have been more frequently deployed in situations that require great restraint. Adversaries are often likely to be elusive and commingled with noncombatants. There has been some shift in public opinion away from tolerance of collateral casualties. Therefore there is a need to be able to apply force while limiting casualties. Non-lethal weapons provide part of the solution. Among the changes that will influence the future have been studies by the US and NATO concerning the use of non-lethal weapons, coincidental with increased funding for their development and testing. New concepts and policies have recently been formalized. Surprisingly, the most strident objections to the implementation of non-lethal weapons have come from organizations that are ostensibly designed to protect non-combatants. These arguments are specious and, while technically and academically challenging, actually serve to foster an environment that will result in the deaths of many more innocent civilians. They misconstrue technology with human intent. The reasons for use of force will not abate. Alternatives to bombs, missiles, tanks and artillery must therefore be found. Non-lethal weapons are not a panacea but do offer the best hope of minimizing casualties while allowing nations or alliances the means to use force in protection of national or regional interests. PMID:11578037

  18. Analysis of Ebola Glycoprotein Sequences from Strains of Varying Lethality

    E-print Network

    Analysis of Ebola Glycoprotein Sequences from Strains of Varying Lethality Biochem 218 Spring 2002 Tammy Doukas tdoukas@stanford.edu I. Background and Significance Ebola hemorrhagic fever is a disease in humans, chimpanzees, and monkeys, caused by infection with Ebola virus, and associated with high

  19. Physicians' Attitudes About Involvement in Lethal Injection for Capital Punishment

    Microsoft Academic Search

    Neil Farber; Elizabeth B. Davis; Joan Weiner; Janine Jordan; E. Gil Boyer; Peter A. Ubel

    2000-01-01

    Background: Physicians could play various roles in car- rying out capital punishment via lethal injection. Medi- cal societies like the American Medical Association (AMA) and American College of Physicians have established which roles are acceptable and which are disallowed. No one has explored physicians' attitudes toward their po- tential roles in this process. Methods: We surveyed physicians about how accept-

  20. Energetics of cellular repair processes in a respiratory-deficient mutant of yeast. [UV

    SciTech Connect

    Jain, V.K.; Gupta, I.; Lata, K.

    1982-12-01

    Repair of potentially lethal damage induced by cytoxic agents like UV irradiation (254 nm), psorelen-plus-UVA (365 mn), and methyl methanesulfonate has been studied in the presence of a glucose analog, 2-deoxy-D-glucose, in yeast cells. Simultaneously, effects of 2-deoxy-D-glucose were also investigated on parameters of energy metabolism like glucose utilization, rate of ATP production, and ATP content of cells. The following results were obtained. (i) 2-Deoxy-D-glucose is able to inhibit repair of potentially lethal damage induced by all the cytotoxic agents tested. The 2-deoxy-D-glucose-induced inhibition of repair depends upon the type of lesion and the pattern of cellular energy metabolism, the inhibition being greater in respiratory-deficient mutants than in the wild type. (ii) A continuous energy flow is necessary for repair of potentially lethal damage in yeast cells. Energy may be supplied by the glycolytic and/or the respiratory pathway; respiratory metabolism is not essential for this purpose. (iii) The magnitude of repair correlates with the rate of ATP production in a sigmoid manner.

  1. Pleiotropic phenotypes of a Yersinia enterocolitica flhD mutant include reduced lethality in a chicken embryo model

    Microsoft Academic Search

    Megan K Townsend; Nathan J Carr; Jyoti G Iyer; Shelley M Horne; Penelope S Gibbs; Birgit M Prüß

    2008-01-01

    BACKGROUND: The Yersinia enterocolitica flagellar master regulator FlhD\\/FlhC affects the expression levels of non-flagellar genes, including 21 genes that are involved in central metabolism. The sigma factor of the flagellar system, FliA, has a negative effect on the expression levels of seven plasmid-encoded virulence genes in addition to its positive effect on the expression levels of eight of the flagellar

  2. Out-crossing between 'Bacon' pollinizers and adjacent 'Hass' avocado and the identification of two new avocado lethal mutants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Avocado (Persea americana Mill) has an unusual flowering mechanism, diurnally synchronous protogynous dichogamy, which promotes cross pollination among avocado genotypes. In commercial groves, which usually contain pollinizer rows adjacent to the more desirable commercial cultivars, the rate of out-...

  3. Pax1\\/E2a Double-Mutant Mice Develop Non-Lethal Neural Tube Defects that Resemble Human Malformations

    Microsoft Academic Search

    Paulus H. L. J. Joosten; Everardus J. J. van Zoelen; Cornelis Murre

    2005-01-01

    Many mouse models exist for neural tube defects (NTDs), but only few of them are relevant for human patients that are born\\u000a alive with spina bifida aperta. NTDs in humans show a complex inheritance, which most likely result from the involvement of\\u000a a variety of predisposing genetic and environmental factors. Hints toward the identity of predisposing genetic factors for\\u000a human

  4. Nitrate reductase deficient cell lines from diploid cell cultures and lethal mutant M2 plants of Arabidopsis thaliana

    Microsoft Academic Search

    H. J. Scholten; S. E. de Vries; H. Nijdam; W. J. Feenstra

    1985-01-01

    Cell suspensions of diploid Arabidopsis thaliana were screened for resistance to chlorate on a medium with ammonium nitrate as the nitrogen source, and after plating on filters to increase the plating efficiency. Thirty-nine lines were selected, four of which were still resistant after two years of subculturing on non-selective medium. Of the latter lines three were nitrate reductase deficient but

  5. Lethal poisoning with ethiofencarb and ethanol.

    PubMed

    Al-Samarraie, Muhammad S J; Karinen, Ritva; Rognum, Torleiv; Hasvold, Inger; Opdal Stokke, Mimi; Christophersen, Asbjørg S

    2009-09-01

    Ethiofencarb is one of the carbamate compounds, which are, in general, less toxic than organophosphorus insecticides. This is due to their reversible acetylcholinesterase inhibition and relative inability to cross the blood-brain barrier. Generally, ethiofencarb is regarded to be of low toxicity (LD(50) > 200 mg/kg); however, severe poisoning and death are not uncommon. To our knowledge, no measurements of ethiofencarb and its metabolites in human postmortem whole blood have been published. We present here a case report of fatal ethiofencarb intoxication with quantitative analysis of ethiofencarb and its metabolites in ante- and postmortem blood. In addition, postmortem urine was collected and analyzed. A 56-year-old man, who worked as a gardener, was found in poor condition, sitting in his car seat. He had been vomiting. The man was admitted to the local hospital about 1 h later. At admission, he was conscious, but unable to speak clearly. His condition deteriorated, and he developed severe pulmonary edema. Resuscitation with atropine and adrenaline were attempted, but he died approximately 3 h after admission. The analysis of postmortem peripheral blood revealed 0.12 g/100 mL ethanol, 26.4 mg/L ethiofencarb, 37.9 mg/L ethiofencarbsulfoxide, and 0.9 mg/L ethiofencarbsulfone. Ethanol (0.26 g/100 mL), ethiofencarb, ethiofencarbsulfoxide, and ethiofencarbsulfone were also detected in urine. PMID:19796510

  6. A Multivariate Model of Stakeholder Preference for Lethal Cat Management

    PubMed Central

    Wald, Dara M.; Jacobson, Susan K.

    2014-01-01

    Identifying stakeholder beliefs and attitudes is critical for resolving management conflicts. Debate over outdoor cat management is often described as a conflict between two groups, environmental advocates and animal welfare advocates, but little is known about the variables predicting differences among these critical stakeholder groups. We administered a mail survey to randomly selected stakeholders representing both of these groups (n?=?1,596) in Florida, where contention over the management of outdoor cats has been widespread. We used a structural equation model to evaluate stakeholder intention to support non-lethal management. The cognitive hierarchy model predicted that values influenced beliefs, which predicted general and specific attitudes, which in turn, influenced behavioral intentions. We posited that specific attitudes would mediate the effect of general attitudes, beliefs, and values on management support. Model fit statistics suggested that the final model fit the data well (CFI?=?0.94, RMSEA?=?0.062). The final model explained 74% of the variance in management support, and positive attitudes toward lethal management (humaneness) had the largest direct effect on management support. Specific attitudes toward lethal management and general attitudes toward outdoor cats mediated the relationship between positive (p<0.05) and negative cat-related impact beliefs (p<0.05) and support for management. These results supported the specificity hypothesis and the use of the cognitive hierarchy to assess stakeholder intention to support non-lethal cat management. Our findings suggest that stakeholders can simultaneously perceive both positive and negative beliefs about outdoor cats, which influence attitudes toward and support for non-lethal management. PMID:24736744

  7. Development of a non-lethal method for evaluating transcriptomic endpoints in Arctic grayling (Thymallus arcticus).

    PubMed

    Veldhoen, Nik; Beckerton, Jean E; Mackenzie-Grieve, Jody; Stevenson, Mitchel R; Truelson, Robert L; Helbing, Caren C

    2014-07-01

    With increases in active mining and continued discharge associated with former mine operations, evaluating the health of watersheds in the Canadian Yukon Territory is warranted. Current environmental assessment approaches often employ guidelines established using sentinel species not relevant to Arctic monitoring programs. The present study focused on the successful development of a quantitative real-time polymerase chain reaction (qPCR) assay directed towards the indigenous Arctic grayling (Thymallus arcticus) and examines the feasibility of using non-lethal sampling from the caudal fin as a means for evaluation of mRNA abundance profiles reflective of environmental conditions. In a proof of concept study performed blind, qPCR results from animals in an area with elevated water concentrations of cadmium (Cd) and zinc (Zn) and higher body burdens of Cd, Zn, and lead (Pb) were compared to a reference location in the Yukon Territory. Lower condition factor and a higher abundance of hepatic and caudal fin gene transcripts encoding the metallothionein isoforms (mta/mtb), in addition to elevated heat shock protein 70 (hsp70) and catalase (cat) mRNAs in liver, were observed in fish from the test site. The strong positive correlation between metal body burden and caudal fin mta/mtb mRNA abundance demonstrates a high potential for use of the Arctic grayling assay in non-lethal environmental monitoring programs. PMID:24780232

  8. Mutation of Murine Sox4 Untranslated Regions Results in Partially Penetrant Perinatal Lethality

    PubMed Central

    Wiles, Walter Guy; Mou, Zhongming; Du, Yang; Long, Alyssa B.; Scharer, Christopher D.; Bilir, Birdal; Spyropoulos, Demetri D.; Jenkins, Nancy A.; Copeland, Neal G.; Martin, W. David; Moreno, Carlos S.

    2014-01-01

    Background Sox4 is an essential gene, and genetic deletion results in embryonic lethality. In an effort to develop mice with tissue-specific deletion, we bred conditional knockout mice bearing LoxP recombination sites flanking the Sox4 gene, with the LoxP sites located in the Sox4 5’UTR and 3’UTR. Results The number of mice homozygous for this LoxP-flanked conditional knockout allele was far below the expected number, suggesting embryonic lethality with reduced penetrance. From over 200 animals bred, only 11% were homozygous Sox4flox/flox mice compared to the expected Mendelian ratio of 25% (p < 0.001). Moreover, there was a significant reduction in the number of female Sox4flox/flox mice (26%) relative to male Sox4flox/flox mice (p = 0.0371). Reduced Sox4 expression in homozygous embryos was confirmed by in-situ hybridization and Quantitative real-time polymerase chain reaction (QPCR). Conclusions LoxP sites in the 5’ and 3’ UTR of both alleles of Sox4 resulted in reduced, but variable expression of Sox4 message. PMID:25189881

  9. Temperature-Sensitive Lethal Mutations on Yeast Chromosome I Appear to Define Only a Small Number of Genes

    PubMed Central

    Kaback, David B.; Oeller, Paul W.; Steensma, H. Yde; Hirschman, Janet; Ruezinsky, Diane; Coleman, Kevin G.; Pringle, John R.

    1984-01-01

    A method was developed for isolating large numbers of mutations on chromosome I of the yeast Saccharomyces cerevisiae. A strain monosomic for chromosome I (i.e., haploid for chromosome I and diploid for all other chromosomes) was mutagenized with either ethyl methanesulfonate or N-methyl-N'-nitro-N -nitrosoguanidine and screened for temperature-sensitive (Ts- ) mutants capable of growth on rich, glucose-containing medium at 25° but not at 37°. Recessive mutations induced on chromosome I are expressed, whereas those on the diploid chromosomes are usually not expressed because of the presence of wild-type alleles on the homologous chromosomes. Dominant ts mutations on all chromosomes should also be expressed, but these appeared rarely. — Of the 41 ts mutations analyzed, 32 mapped on chromosome I. These 32 mutations fell into only three complementation groups, which proved to be the previously described genes CDC15, CDC24 and PYK1 (or CDC19). We recovered 16 or 17 independent mutations in CDC15, 12 independent mutations in CDC24 and three independent mutations in PYK1. A fourth gene on chromosome I, MAK16, is known to be capable of giving rise to a ts-lethal allele, but we recovered no mutations in this gene. The remaining nine mutations isolated using the monosomic strain appeared not to map on chromosome I and were apparently expressed in the original mutants because they had become homozygous or hemizygous by mitotic recombination or chromosome loss. — The available information about the size of chromosome I suggests that it should contain approximately 60–100 genes. However, our isolation in the monosomic strain of multiple, independent alleles of just three genes suggests that only a small proportion of the genes on chromosome I is easily mutable to give a Ts--lethal phenotype. — During these studies, we located CDC24 on chromosome I and determined that it is centromere distal to PYK1 on the left arm of the chromosome. PMID:6383953

  10. Inactivating mutations in MFSD2A, required for omega-3 fatty acid transport in brain, cause a lethal microcephaly syndrome.

    PubMed

    Guemez-Gamboa, Alicia; Nguyen, Long N; Yang, Hongbo; Zaki, Maha S; Kara, Majdi; Ben-Omran, Tawfeg; Akizu, Naiara; Rosti, Rasim Ozgur; Rosti, Basak; Scott, Eric; Schroth, Jana; Copeland, Brett; Vaux, Keith K; Cazenave-Gassiot, Amaury; Quek, Debra Q Y; Wong, Bernice H; Tan, Bryan C; Wenk, Markus R; Gunel, Murat; Gabriel, Stacey; Chi, Neil C; Silver, David L; Gleeson, Joseph G

    2015-07-01

    Docosahexanoic acid (DHA) is the most abundant omega-3 fatty acid in brain, and, although it is considered essential, deficiency has not been linked to disease. Despite the large mass of DHA in phospholipids, the brain does not synthesize it. DHA is imported across the blood-brain barrier (BBB) through the major facilitator superfamily domain-containing 2a (MFSD2A) protein. MFSD2A transports DHA as well as other fatty acids in the form of lysophosphatidylcholine (LPC). We identify two families displaying MFSD2A mutations in conserved residues. Affected individuals exhibited a lethal microcephaly syndrome linked to inadequate uptake of LPC lipids. The MFSD2A mutations impaired transport activity in a cell-based assay. Moreover, when expressed in mfsd2aa-morphant zebrafish, mutants failed to rescue microcephaly, BBB breakdown and lethality. Our results establish a link between transport of DHA and LPCs by MFSD2A and human brain growth and function, presenting the first evidence of monogenic disease related to transport of DHA in humans. PMID:26005868

  11. Biological and genetic characterization of TnphoA mutants of Salmonella typhimurium TML in the context of gastroenteritis.

    PubMed Central

    Lodge, J; Douce, G R; Amin, I I; Bolton, A J; Martin, G D; Chatfield, S; Dougan, G; Brown, N L; Stephen, J

    1995-01-01

    TnphoA transposon insertion mutants of phoN-negative derivatives of Salmonella typhimurium TML (of human gastroenteritic origin) were selected by growing mutagenized recipient bacteria under a variety of growth conditions. Ninety-seven individual mutants, which expressed alkaline phosphatase, were collected and tested for their ability to invade HEp-2 cells. Seven smooth mutants had a reduced ability to invade HEp-2 cells, and three smooth mutants were consistently more invasive than their corresponding parental strains. One rough mutant was of similar invasiveness and two were of reduced invasiveness when compared with that of parental strains. The seven smooth hypoinvasive mutants, the three smooth hyperinvasive mutants, and the three rough mutant strains were tested for their abilities to invade ileal enterocytes by the rabbit ileal invasion assay described previously (3). All smooth mutants exhibited parental levels of invasiveness. The rough mutants were hypoinvasive in the rabbit ileal invasion assay. The HEp-2 system is therefore not a good predictor of behavior in gut tissue in this model. DNA sequences flanking the transposon were determined for five mutants which were hypoinvasive in the HEp-2 cell assay. The mutations were found to be insertions in two previously identified invasion genes, invG and invH, and in a gene not normally associated with invasion, pagC. These observations lead one to be cautious in the interpretation of the biological significance of data obtained from invasion of tissue culture monolayers when extrapolated to gut tissue. PMID:7868245

  12. The study of the influence of secondary biogenic radiation on genetic and physiological changes in plants grown from seeds kept for a long time under space flight conditions

    NASA Astrophysics Data System (ADS)

    Yurov, S.; Nechitailo, G.; Dmitrievskiy, I.

    Analysis of the biological investigations carried out at the Russian space stations showed that the combined action of low radiation doses and altered gravitation causes considerable genetic and physiological changes in plants grown from seeds kept for a long time under space flight conditions The results of the investigations with tomato plants produced from seeds staying for a long time at the MIR station are presented in the work The seeds of the flight samples had 26 8 germinating capacity whereas in the control it was 58 3 To reveal hidden changes undetectable with conventional methods the method of regeneration of conditionally lethal mutations under the action of secondary biogenic radiation developed by us previously was used On the basis of preliminarily studied bacteriophage T4B mutations obtained in experiments with accelerators in highland and space flight conditions an optimal dose of Cs137 gamma-radiation in the range from 1e-2 cGy to 1e-4 cGy was chosen which generates secondary biogenic radiation The germinating capacity of the tomato seeds exposed to secondary biogenic radiation was 4 times higher as compared to the initial one and made up 75 The generations of plants exposed to the biogenic influence had specific morphological mutations cotyledon-free and leafless stumps called by us hypocotel stumps Such mutants obtained from conventionally lethal seeds under the action of biogenic radiation have never been observed in the control and experimental variants There are data for 2000 tomato mutations including

  13. Role of kit-ligand in proliferation and suppression of apoptosis in mast cells: basis for radiosensitivity of white spotting and steel mutant mice

    PubMed Central

    1994-01-01

    The receptor tyrosine kinase Kit and its cognate ligand KL/steel factor are encoded at the white spotting (W) and Steel (Sl) loci of the mouse, respectively. Mutations at both the W and the Sl loci affect hematopoiesis including the stem cell hierarchy, erythropoiesis, and mast cells, as well as gametogenesis and melanogenesis. In addition, mutant mice display an increased sensitivity to lethal doses of irradiation. The role of KL/c-kit in cell proliferation and survival under conditions of growth factor-deprivation and gamma-irradiation was studied by using bone marrow-derived mast cells (BMMC) as a model. Whereas apoptosis induced by growth factor deprivation in BMMC is a stochastic process and follows zero order kinetics, gamma-irradiation- induced apoptosis is an inductive process and follows higher order kinetics. In agreement with these results, gamma-irradiation-induced apoptosis in BMMC was shown to be dependent on p53 whereas apoptosis induced by deprivation is partly dependent on p53, implying that there are other mechanisms mediating apoptosis in KL-deprived BMMC. In the presence and in the absence of serum, KL stimulated proliferation by promoting cell cycle progression. The presence of KL was required only during the early part of the G1 phase for entry into the S phase. At concentrations lower than those required for proliferation, KL suppressed apoptosis induced by both growth factor-deprivation and gamma-irradiation, and internucleosomal DNA fragmentation characteristic of apoptosis. The ability of KL to suppress apoptosis was independent of the phase of the cell cycle in which the cells were irradiated and suppression of apoptosis was a prerequisite for subsequent cell cycle progression. Moreover, addition of KL to gamma- irradiated and growth factor-deprived cells could be delayed for up to 1 h after irradiation or removal of growth factors when cells became irreversibly committed to apoptosis. KL and IL-3 induce suppression of apoptosis in mast cells by different mechanisms based on the observations of induction of bcl-2 gene expression by IL-3 but not by KL. It is proposed that the increased sensitivity of W and Sl mutant mice to lethal irradiation results from paucity of the apoptosis suppressing and proliferative effects of KL. PMID:7515099

  14. Embryonic Lethality and Fetal Liver Apoptosis in Mice Lacking All Three Small Maf Proteins

    PubMed Central

    Yamazaki, Hiromi; Katsuoka, Fumiki; Motohashi, Hozumi; Engel, James Douglas

    2012-01-01

    Embryogenesis is a period during which cells are exposed to dynamic changes of various intracellular and extracellular stresses. Oxidative stress response genes are regulated by heterodimers composed of Cap'n'Collar (CNC) and small Maf proteins (small Mafs) that bind to antioxidant response elements (ARE). Whereas CNC factors have been shown to contribute to the expression of ARE-dependent cytoprotective genes during embryogenesis, the specific contribution of small Maf proteins to such gene regulation remains to be fully examined. To delineate the small Maf function in vivo, in this study we examined mice lacking all three small Mafs (MafF, MafG, and MafK). The small Maf triple-knockout mice developed normally until embryonic day 9.5 (E9.5). Thereafter, however, the triple-knockout embryos showed severe growth retardation and liver hypoplasia, and the embryos died around E13.5. ARE-dependent cytoprotective genes were expressed normally in E10.5 triple-knockout embryos, but the expression was significantly reduced in the livers of E13.5 mutant embryos. Importantly, the embryonic lethality could be completely rescued by transgenic expression of exogenous MafG under MafG gene regulatory control. These results thus demonstrate that small Maf proteins are indispensable for embryonic development after E9.5, especially for liver development, but early embryonic development does not require small Mafs. PMID:22158967

  15. Ion conductance of the stem of the anthrax toxin channel during lethal factor translocation.

    PubMed

    Schiffmiller, Aviva; Finkelstein, Alan

    2015-03-27

    The tripartite anthrax toxin consists of protective antigen, lethal factor (LF), and edema factor. PA63 (the 63-kDa, C-terminal part of protective antigen) forms heptameric channels in cell membranes that allow for the transport of LF and edema factor into the cytosol. These channels are mushroom shaped, with a ring of seven phenylalanine residues (known as the phenylalanine clamp) lining the junction between the cap and the stem. It is known that when LF is translocated through the channel, the phenylalanine clamp creates a seal that causes an essentially complete block of conduction. In order to examine ion conductance in the stem of the channel, we used Venus yellow fluorescent protein as a molecular stopper to trap LFN (the 30-kDa, 263-residue N-terminal segment of LF), as well as various truncated constructs of LFN, in mutant channels in which the phenylalanine clamp residues were mutated to alanines. Here we present evidence that ion movement occurs within the channel stem (but is stopped, of course, at the phenylalanine clamp) during protein translocation. Furthermore, we also propose that the lower region of the stem plays an important role in securing peptide chains during translocation. PMID:24996036

  16. Abnormalities in cell proliferation and apico-basal cell polarity are separable in Drosophila lgl mutant clones in the developing eye

    Microsoft Academic Search

    Nicola A. Grzeschik; Nancy Amin; Julie Secombe; Anthony M. Brumby; Helena E. Richardson

    2007-01-01

    In homozygous mutants of Drosophila lethal-2-giant larvae (lgl), tissues lose apico-basal cell polarity and exhibit ectopic proliferation. Here, we use clonal analysis in the developing eye to investigate the effect of lgl null mutations in the context of surrounding wild-type tissue. lgl? clones in the larval eye disc exhibit ectopic expression of the G1–S regulator, Cyclin E, and ectopic proliferation,

  17. Increased cytotoxicity of normal rabbit serum for lectin-resistant mutants of animal cells

    PubMed Central

    1984-01-01

    Plant lectins are cytotoxic and can be used to select for mutants of animal cells that exhibit structural changes in cell surface carbohydrates reflecting glycosylation defects. We isolated eight lectin mutants of Chinese hamster ovary (CHO) cells that appear to represent three different phenotype classes. These lectin mutants were much more sensitive to the cytotoxic action of normal rabbit serum (NRS) than were the parental cells. This increased cytotoxicity was heat sensitive, specifically absorbed, and inhibited by simple and complex carbohydrates. No killing was observed under conditions in which only the alternate complement pathway was active. An NRS- resistant subclone that was isolated from one lectin mutant was shown to have also regained wild type behavior when tested with the lectins. The possibility that naturally occurring antibodies in rabbit serum are reacting with incomplete carbohydrate chains on the surface of the lectin mutants is discussed. PMID:6481303

  18. Stationary-phase mutants of Sinorhizobium meliloti are impaired in stationary-phase survival or in recovery to logarithmic growth.

    PubMed Central

    Uhde, C; Schmidt, R; Jording, D; Selbitschka, W; Pühler, A

    1997-01-01

    A screening method was used to identify Sinorhizobium meliloti mutants which are affected in stationary-phase survival. Of 20,000 individual colonies mutagenized with transposon Tn5-B20, 10 mutant strains which showed poor or no survival in the stationary phase were identified. Analyses of expression patterns of the promoterless lacZ genes in the mutant strains revealed individual induction patterns. Most strains were induced in stationary phase as well as under carbon limitation and in pure H2O, but none of the mutants was induced under heat, alkali stress conditions, or low oxygen tension. Plant inoculation tests revealed that the symbiotic proficiency of the mutants was not affected. Two mutants, however, showed gene induction not only in the stationary phase under free-living conditions but also in the bacteroid state. A long-term starvation test was carried out to examine the ability of the 10 mutants to survive prolonged stationary-phase conditions. All mutants showed a clear decrease in the colony-forming ability under the chosen experimental conditions. Staining with green and red fluorescent nucleic acid stain showed that the mutants fell into two different classes. Seven mutants died during stationary phase; the three other mutants remained viable but did not resume growth after prolonged starvation. Five of the ten Tn5-B20 insertions were cloned from the genomes of the mutant strains. Nucleotide sequence analyses established that the transposon had inserted in five distinctive genes. Database searches revealed that four of the tagged loci corresponded to already characterized genes whose gene products are involved in important cellular processes such as amino acid metabolism or aerobic respiration. PMID:9335293

  19. NH4+-Excreting Azospirillum brasilense Mutants Enhance the Nitrogen Supply of a Wheat Host

    PubMed Central

    Christiansen-Weniger, C.; Van Veen, J. A.

    1991-01-01

    Spontaneous ethylenediamine-resistant mutants of Azospirillum brasilense were selected on the basis of their excretion of NH4+. Two mutants exhibited no repression of their nitrogenase enzyme systems in the presence of high (20 mM) concentrations of NH4+. The nitrogenase activities of these mutants on nitrogen-free minimal medium were two to three times higher than the nitrogenase activity of the wild type. The mutants excreted substantial amounts of ammonia when they were grown either under oxygen-limiting conditions (1 kPa of O2) or aerobically on nitrate or glutamate. The mutants grew well on glutamate as a sole nitrogen source but only poorly on NH4Cl. Both mutants failed to incorporate [14C]methylamine. We demonstrated that nitrite ammonification occurs in the mutants. Wild-type A. brasilense, as well as the mutants, became established in the rhizospheres of axenically grown wheat plants at levels of > 107 cells per g of root. The rhizosphere acetylene reduction activity was highest in the preparations containing the mutants. When plants were grown on a nitrogen-free nutritional medium, both mutants were responsible for significant increases in root and shoot dry matter compared with wild-type-treated plants or with noninoculated controls. Total plant nitrogen accumulation increased as well. When they were exposed to a 15N2-enriched atmosphere, both A. brasilense mutants incorporated significantly higher amounts of 15N inside root and shoot material than the wild type did. The results of our nitrogen balance and 15N enrichment studies indicated that NH4+-excreting A. brasilense strains potentially support the nitrogen supply of the host plants. PMID:16348569

  20. 40 CFR 798.5275 - Sex-linked recessive lethal test in drosophila melanogaster.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 2014-07-01 false Sex-linked recessive lethal test in drosophila...GUIDELINES Genetic Toxicity § 798.5275 Sex-linked recessive lethal test in drosophila melanogaster. (a) Purpose. The sex-linked recessive lethal (SLRL)...

  1. 40 CFR 798.5275 - Sex-linked recessive lethal test in drosophila melanogaster.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 2013-07-01 false Sex-linked recessive lethal test in drosophila...GUIDELINES Genetic Toxicity § 798.5275 Sex-linked recessive lethal test in drosophila melanogaster. (a) Purpose. The sex-linked recessive lethal (SLRL)...

  2. 40 CFR 798.5275 - Sex-linked recessive lethal test in drosophila melanogaster.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 2012-07-01 false Sex-linked recessive lethal test in drosophila...GUIDELINES Genetic Toxicity § 798.5275 Sex-linked recessive lethal test in drosophila melanogaster. (a) Purpose. The sex-linked recessive lethal (SLRL)...

  3. To Laugh in the Face of Death: The Games That Lethal People Play.

    ERIC Educational Resources Information Center

    Thorson, James A.; Powell, F. C.

    1990-01-01

    A total of 399 individuals completed a lethal behaviors scale and a measure of death anxiety, which were found to have no significant correlation. Predictors of lethalness included doing dangerous things for the fun of it and having ever driven a motorcycle. The most lethal individuals were young, male, and less educated. (Author/ABL)

  4. A Methodology to Assess Lethality and Collateral Damage for Nonfragmenting Precision-Guided Weapons

    Microsoft Academic Search

    Amanda Humphrey; David Faulkner

    2008-01-01

    A methodology was developed to assess lethality and collateral damage for the Focused Lethality Munition (FLM) program. FLM is a new nonfragmenting, precision-guided weapon with damage effects mechanisms that differ from the principal fragmentation damage effects for traditional weapons. To date, guidelines to determine lethality, based on mannequin test data, have not been articulated for nonfragmenting warheads such as FLM.

  5. 28 CFR 552.25 - Use of chemical agents or non-lethal weapons.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... false Use of chemical agents or non-lethal weapons. 552.25 Section...552.25 Use of chemical agents or non-lethal weapons. The Warden may authorize the use of chemical agents or non-lethal weapons only when the...

  6. A New Biological Rhythm Mutant of Drosophila Melanogaster That Identifies a Gene with an Essential Embryonic Function

    PubMed Central

    Newby, L. M.; Jackson, F. R.

    1993-01-01

    To identify components of a circadian pacemaker output pathway, we have sought Drosophila mutations that alter the timing of eclosion but do not perturb circadian period or the expression of the activity rhythm. A mutant named lark has been identified, for which daily peaks of eclosion occur abnormally early while populations are synchronized to either light/dark or temperature cycles. The temporal phasing of locomotor activity in lark mutants, however, is entirely normal, as is the free-running period of the circadian pacemaker. The lark strain carries a single P-element insertion which, interestingly, has a dominant effect on the timing of eclosion, but is also associated with a recessive embryonic lethal phenotype. The analysis of excision-generated alleles suggests that the lark gene encodes an essential function. This function is apparently mediated by a transcription unit that is interrupted by the P-induced lark mutation. A combination of in situ hybridization analysis and reporter (?-gal) staining indicates that this transcription unit expresses mRNAs throughout the embryonic central nervous system and in a defined subset of cells in the nervous system of pharate adults. RNAs are first detected at about embryonic stage 11, just prior to the stage at which lethality occurs in lark homozygotes. Based primarily on the observed mutant phenotypes, a function is proposed for the LARK product(s) that is consistent with the pleiotropic nature of lark mutations. PMID:8307324

  7. Mutant IDH is sufficient to initiate enchondromatosis in mice

    PubMed Central

    Hirata, Makoto; Sasaki, Masato; Cairns, Rob A.; Inoue, Satoshi; Puviindran, Vijitha; Li, Wanda Y.; Snow, Bryan E.; Jones, Lisa D.; Wei, Qingxia; Sato, Shingo; Tang, Yuning J.; Nadesan, Puviindran; Rockel, Jason; Whetstone, Heather; Poon, Raymond; Weng, Angela; Gross, Stefan; Straley, Kimberly; Gliser, Camelia; Xu, Yingxia; Wunder, Jay; Mak, Tak W.; Alman, Benjamin A.

    2015-01-01

    Enchondromas are benign cartilage tumors and precursors to malignant chondrosarcomas. Somatic mutations in the isocitrate dehydrogenase genes (IDH1 and IDH2) are present in the majority of these tumor types. How these mutations cause enchondromas is unclear. Here, we identified the spectrum of IDH mutations in human enchondromas and chondrosarcomas and studied their effects in mice. A broad range of mutations was identified, including the previously unreported IDH1-R132Q mutation. These mutations harbored enzymatic activity to catalyze ?-ketoglutarate to d-2-hydroxyglutarate (d-2HG). Mice expressing Idh1-R132Q in one allele in cells expressing type 2 collagen showed a disordered growth plate, with persistence of type X-expressing chondrocytes. Chondrocyte cell cultures from these animals or controls showed that there was an increase in proliferation and expression of genes characteristic of hypertrophic chondrocytes with expression of Idh1-R132Q or 2HG treatment. Col2a1-Cre;Idh1-R132Q mutant knock-in mice (mutant allele expressed in chondrocytes) did not survive after the neonatal stage. Col2a1-Cre/ERT2;Idh1-R132 mutant conditional knock-in mice, in which Cre was induced by tamoxifen after weaning, developed multiple enchondroma-like lesions. Taken together, these data show that mutant IDH or d-2HG causes persistence of chondrocytes, giving rise to rests of growth-plate cells that persist in the bone as enchondromas. PMID:25730874

  8. Mutant IDH is sufficient to initiate enchondromatosis in mice.

    PubMed

    Hirata, Makoto; Sasaki, Masato; Cairns, Rob A; Inoue, Satoshi; Puviindran, Vijitha; Li, Wanda Y; Snow, Bryan E; Jones, Lisa D; Wei, Qingxia; Sato, Shingo; Tang, Yuning J; Nadesan, Puviindran; Rockel, Jason; Whetstone, Heather; Poon, Raymond; Weng, Angela; Gross, Stefan; Straley, Kimberly; Gliser, Camelia; Xu, Yingxia; Wunder, Jay; Mak, Tak W; Alman, Benjamin A

    2015-03-01

    Enchondromas are benign cartilage tumors and precursors to malignant chondrosarcomas. Somatic mutations in the isocitrate dehydrogenase genes (IDH1 and IDH2) are present in the majority of these tumor types. How these mutations cause enchondromas is unclear. Here, we identified the spectrum of IDH mutations in human enchondromas and chondrosarcomas and studied their effects in mice. A broad range of mutations was identified, including the previously unreported IDH1-R132Q mutation. These mutations harbored enzymatic activity to catalyze ?-ketoglutarate to d-2-hydroxyglutarate (d-2HG). Mice expressing Idh1-R132Q in one allele in cells expressing type 2 collagen showed a disordered growth plate, with persistence of type X-expressing chondrocytes. Chondrocyte cell cultures from these animals or controls showed that there was an increase in proliferation and expression of genes characteristic of hypertrophic chondrocytes with expression of Idh1-R132Q or 2HG treatment. Col2a1-Cre;Idh1-R132Q mutant knock-in mice (mutant allele expressed in chondrocytes) did not survive after the neonatal stage. Col2a1-Cre/ERT2;Idh1-R132 mutant conditional knock-in mice, in which Cre was induced by tamoxifen after weaning, developed multiple enchondroma-like lesions. Taken together, these data show that mutant IDH or d-2HG causes persistence of chondrocytes, giving rise to rests of growth-plate cells that persist in the bone as enchondromas. PMID:25730874

  9. Experimental ecology of selected vertebrate species. Final report. [Effects of sub-lethal. gamma. radiation on survival of chipmunks and pocket gophers

    Microsoft Academic Search

    R. T. Hartman; D. L. Graybill

    1976-01-01

    This report summarizes the results of a long term (1960 to 1973) study designed to determine the suitability of various vertebrate species for experimental radioecology, to determine their individual and population characteristics under natural conditions, and to utilize these characteristics to gauge the effects of sub-lethal doses of gamma radiation. The study focused on free ranging populations of Tamias striatus

  10. Electrophysiological study of Drosophila rhodopsin mutants

    PubMed Central

    1986-01-01

    Electrophysiological investigations were carried out on several independently isolated mutants of the ninaE gene, which encodes opsin in R1-6 photoreceptors, and a mutant of the ninaD gene, which is probably important in the formation of the rhodopsin chromophore. In these mutants, the rhodopsin content in R1-6 photoreceptors is reduced by 10(2)-10(6)-fold. Light-induced bumps recorded from even the most severely affected mutants are physiologically normal. Moreover, a detailed noise analysis shows that photoreceptor responses of both a ninaE mutant and a ninaD mutant follow the adapting bump model. Since any extensive rhodopsin-rhodopsin interactions are not likely in these mutants, the above results suggest that such interactions are not needed for the generation and adaptation of light-induced bumps. Mutant bumps are strikingly larger in amplitude than wild-type bumps. This difference is observed both in ninaD and ninaE mutants, which suggests that it is due to severe depletion of rhodopsin content, rather than to any specific alterations in the opsin protein. Lowering or buffering the intracellular calcium concentration by EGTA injection mimics the effects of the mutations on the bump amplitude, but, unlike the mutations, it also affects the latency and kinetics of light responses. PMID:3097245

  11. Relationships between DNA damage and the survival of radiosensitive mutant Chinese hamster cell lines exposed to gamma-radiation: Part 2. Effect of cellular redox status.

    PubMed

    Murray, D; Prager, A; Meyn, R E; Davison, S; Green, A D

    1993-02-01

    To characterize further the nature of the defects underlying the differential radiosensitivities of the Chinese hamster ovary cell lines NM2, EM9, and UV41, we compared the abilities of anoxia and of the thiol WR-1065 to protect these mutants and their parent cell line, AA8, from the lethal effects of gamma-radiation. Wide differences in oxygen enhancement ratios (OERs) for cell killing were observed in the different cell lines, those for UV41 and NM2 cells (1.8 and 2.1, respectively) being reduced and that for EM9 cells (3.3) being slightly (although significantly) increased compared with wild-type AA8 cells (2.9). These OER data support the hypothesis that repair-deficient mutants are hypersensitive to radiation under redox conditions that favour the formation of the particular lesions that correspond to their repair defect, and also support the earlier suggestion that the underlying molecular bases of the radiosensitivity of EM9 and NM2 cells are very different. In contrast to protection by anoxia, a 30-min preirradiation treatment with WR-1065 (4 mmol dm-3) protected aerated AA8, EM9, NM2, and UV41 cells to a similar extent with respect to both cell killing and the efficiency of DNA double-strand break (dsb) induction as measured by neutral elution. This observation is in marked contrast with reports of a greatly reduced protection by thiols for some repair-deficient cell lines and with the above-mentioned anoxia data. Thus, the particular types of mutations characteristic of NM2, EM9, and UV41 cells that give rise to their unusual OERs have little impact on the ability of WR-1065 to modify either cell killing or dsb induction, supporting radiochemical evidence that the types of deoxyribose radicals modifiable by oxygen and thiols are qualitatively different. Furthermore, because the extent of protection of these CHO mutants by thiols and anoxia show no correlation, oxygen depletion cannot be a major component of protection of aerated cells by thiols under these conditions. PMID:8094416

  12. Use of a temperature-sensitive lethal mutation strain of medfly (Ceratitis capitata) for the suppression of pest populations.

    PubMed

    Kerremans, P; Franz, G

    1995-03-01

    Before the Sterile Insect Technique can be applied successfully, the size of the target population has to be reduced to a manageable level. At present this reduction is achieved by the use of insecticides. Computer simulations have been performed to examine the possibility of achieving this initial population suppression by genetic control strategies; in particular, the effect of releasing fertile males carrying a recessive temperature-sensitive lethal mutation and a Y-autosome translocation has been simulated. The results show that the release of such males is most effective when applied under permissive conditions, i.e. those which allow flies homozygous for the temperature-sensitive lethal mutation to survive and spread the mutation through the population. However, combining this population replacement with a population-suppression strategy is even more effective. If the released males are partially sterile, e.g. due to the presence of a Y-autosome translocation, the population size is reduced before the restrictive conditions for the temperature-sensitive lethal mutation are reached, i.e. before the increase of temperatures in the target area eliminates all flies homozygous for this mutation. By combining these two strategies the resulting population should be low enough to apply the Sterile Insect Technique for eradication. PMID:24173945

  13. Electromagnetic pulse (EMP) coupling codes for use with the vulnerability/lethality (VIL) taxonomy. Final report, June-October 1984

    SciTech Connect

    Mar, M.H.

    1995-07-01

    Based on the vulnerability Lethality (V/L) taxonomy developed by the Ballistic Vulnerability Lethality Division (BVLD) of the Survivability Lethality Analysis Directorate (SLAD), a nuclear electromagnetic pulse (EMP) coupling V/L analysis taxonomy has been developed. A nuclear EMP threat to a military system can be divided into two levels: (1) coupling to a system level through a cable, antenna, or aperture; and (2) the component level. This report will focus on the initial condition, which includes threat definition and target description, as well as the mapping process from the initial condition to damaged components state. EMP coupling analysis at a system level is used to accomplish this. This report introduces the nature of EMP threat, interaction between the threat and target, and how the output of EMP coupling analysis at a system level becomes the input to the component level analysis. Many different tools (EMP coupling codes) will be discussed for the mapping process, which correponds to the physics of phenomenology. This EMP coupling V/L taxonomy and the models identified in this report will provide the tools necessary to conduct basic V/L analysis of EMP coupling.

  14. X-ray survival characteristics and genetic analysis for nine saccharomyces deletion mutants that show altered radiation sensitivity

    SciTech Connect

    Game, John C.; Williamson, Marsha S.; Baccari, Clelia

    2004-01-07

    The availability of a genome-wide set of Saccharomyces deletion mutants provides a chance to identify all the yeast genes involved in DNA repair. Using X-rays, we are screening these mutants to identify additional genes that show increased sensitivity to the lethal effects of ionizing radiation. For each mutant identified as sensitive, we are confirming that the sensitivity phenotype co-segregates with the deletion allele and are obtaining multipoint survival-versus-dose assays in at least two haploid and one homozygous diploid strains. We present data for deletion mutants involving the genes DOT1, MDM20, NAT3, SPT7, SPT20, GCN5, HFI1, DCC1 and VID21/EAF1, and discuss their potential roles in repair. Eight of these genes have a clear radiation-sensitive phenotype when deleted, but the ninth, GCN5, has at most a borderline phenotype. None of the deletions confer substantial sensitivity to ultra-violet radiation, although one or two may confer marginal sensitivity. The DOT1 gene is of interest because its only known function is to methylate one lysine residue in the core of the histone H3 protein. We find that histone H3 mutants (supplied by K. Struhl) in which this residue is replaced by other amino-acids are also X-ray sensitive, seeming to confirm that methylation of the lysine-79 residue is required for effective repair of radiation damage.

  15. Attempt to Identify Novel IFT Mutant through PCR Sequencing and Analysis of Chlamydomonas reinhardtii Flagellar Mutants

    E-print Network

    Hernandez, Catherine Marie

    2013-02-06

    and flagella. One route in which to study the flagella organelle is through the creation and analysis of flagellar mutants. Six possible C. reinhardtii IFT mutants (created from a previous transformation process and confirmed through a phototaxis test) were...

  16. The lethality test used for estimating the potency of antivenoms against Bothrops asper snake venom: pathophysiological mechanisms, prophylactic analgesia, and a surrogate in vitro assay.

    PubMed

    Chacón, Francisco; Oviedo, Andrea; Escalante, Teresa; Solano, Gabriela; Rucavado, Alexandra; Gutiérrez, José María

    2015-01-01

    The potency of antivenoms is assessed by analyzing the neutralization of venom-induced lethality, and is expressed as the Median Effective Dose (ED50). The present study was designed to investigate the pathophysiological mechanisms responsible for lethality induced by the venom of Bothrops asper, in the experimental conditions used for the evaluation of the neutralizing potency of antivenoms. Mice injected with 4 LD50s of venom by the intraperitoneal route died within ?25 min with drastic alterations in the abdominal organs, characterized by hemorrhage, increment in plasma extravasation, and hemoconcentration, thus leading to hypovolemia and cardiovascular collapse. Snake venom metalloproteinases (SVMPs) play a predominat role in lethality, as judged by partial inhibition by the chelating agent CaNa2EDTA. When venom was mixed with antivenom, there was a venom/antivenom ratio at which hemorrhage was significantly reduced, but mice died at later time intervals with evident hemoconcentration, indicating that other components in addition to SVMPs also contribute to plasma extravasation and lethality. Pretreatment with the analgesic tramadol did not affect the outcome of the neutralization test, thus suggesting that prophylactic (precautionary) analgesia can be introduced in this assay. Neutralization of lethality in mice correlated with neutralization of in vitro coagulant activity in human plasma. PMID:25447772

  17. An improved brine shrimp larvae lethality microwell test method.

    PubMed

    Zhang, Yi; Mu, Jun; Han, Jinyuan; Gu, Xiaojie

    2012-01-01

    This article described an improved brine shrimp larvae lethality microwell test method. A simply designed connecting vessel with alternative photoperiod was used to culture and collect high yield of active Artemia parthenogenetica nauplii for brine shrimp larvae lethality microwell test. Using this method, pure A. parthenogenetica nauplii suspension was easily cultured and harvested with high density about 100-150 larvae per milliliter and the natural mortality was reduced to near zero by elimination of unnecessary artificial disturbance. And its sensitivity was validated by determination of LC(50)-24 h of different reference toxicants including five antitumor agents, two pesticides, three organic pollutants, and four heavy metals salts, most of which exhibited LC(50)-24 h between 0.07 and 58.43 mg/L except for bleomycin and mitomycin C with LC(50)-24 h over 300 mg/L. PMID:21859360

  18. Harnessing synthetic lethal interactions in anticancer drug discovery

    PubMed Central

    Chan, Denise A.; Giaccia, Amato J.

    2013-01-01

    Unique features of tumours that can be exploited by targeted therapies are a key focus of current cancer research. One such approach is known as synthetic lethality screening, which involves searching for genetic interactions of two mutations whereby the presence of either mutation alone has no effect on cell viability but the combination of the two mutations results in cell death. The presence of one of these mutations in cancer cells but not in normal cells can therefore create opportunities to selectively kill cancer cells by mimicking the effect of the second genetic mutation with targeted therapy. Here, we summarize strategies that can be used to identify synthetic lethal interactions for anticancer drug discovery, describe examples of such interactions that are currently being investigated in preclinical and clinical studies of targeted anticancer therapies, and discuss the challenges of realizing the full potential of such therapies. PMID:21532565

  19. Invasive pneumococcal disease: association between serotype, clinical presentation and lethality.

    PubMed

    Rodríguez, M Angeles Gutiérrez; González, Amai Varela; Gavín, María Ascensión Ordobás; Martínez, Fernando Martín; Marín, Natividad García; Blázquez, Belén Ramos; Moreno, Juan Carlos Sanz

    2011-08-01

    To ascertain the factors linked to invasive pneumococcal disease (IPD) caused by the different serotypes in the period 2007-2009, following the conjugate vaccine's inclusion in the childhood vaccination schedule, a total of 2013 IPD cases were reviewed. The mean annual incidence in this period was 10.74 cases per 100,000 inhabitans and the lethality was 8.8%. Overall serotype distribution displayed certain peculiarities, such as the high frequency of serotype 5. Serotype 3, male gender, sepsis and presence of risk factors were significantly associated with lethality. Vaccinated children under 5 years of age had a higher risk of disease due to serotype 19A. Serotype 8 was associated with the presence of underlying risk factors. PMID:21683112

  20. A framework for the assessment of non-lethal weapons.

    PubMed

    Rappert, Brian

    2004-01-01

    In many government, police and military circles, attention is being given to so-called 'non-lethal' weapons as means of reducing many of the negative effects directly or indirectly associated with the use of force. Despite the purported ability of the adoption of such weaponry to lessen grounds for contention and concern, past experience suggests the need for scepticism regarding the purported benefits. Rather than relying on poorly substantiated claims, comprehensive procedures are needed to ensure the appropriateness of force options. This article outlines some of the institutional structures required for 'carefully evaluating' and 'carefully controlling' non-lethal weapons, with a discussion of the perennial tensions associated with ensuring the relative 'acceptability' of the use of force. PMID:15015546

  1. An update to the list of mouse mutants with neural tube closure defects and advances toward a complete genetic perspective of neural tube closure.

    PubMed

    Harris, Muriel J; Juriloff, Diana M

    2010-08-01

    The number of mouse mutants and strains with neural tube defects (NTDs) now exceeds 240, including 205 representing specific genes, 30 for unidentified genes, and 9 multifactorial strains. These mutants identify genes needed for embryonic neural tube closure. Reports of 50 new NTD mutants since our 2007 review (Harris and Juriloff, 2007) were considered in relation to the previously reviewed mutants to obtain new insights into mechanisms of NTD etiology. In addition to null mutations, some are hypomorphs or conditional mutants. Some mutations do not cause NTDs on their own, but do so in digenic, trigenic, and oligogenic combinations, an etiology that likely parallels the nature of genetic etiology of human NTDs. Mutants that have only exencephaly are fourfold more frequent than those that have spina bifida aperta with or without exencephaly. Many diverse cellular functions and biochemical pathways are involved; the NTD mutants draw new attention to chromatin modification (epigenetics), the protease-activated receptor cascade, and the ciliopathies. Few mutants directly involve folate metabolism. Prevention of NTDs by maternal folate supplementation has been tested in 13 mutants and reduces NTD frequency in six diverse mutants. Inositol reduces spina bifida aperta frequency in the curly tail mutant, and three new mutants involve inositol metabolism. The many NTD mutants are the foundation for a future complete genetic understanding of the processes of neural fold elevation and fusion along mechanistically distinct cranial-caudal segments of the neural tube, and they point to several candidate processes for study in human NTD etiology. PMID:20740593

  2. Optimized Production and Purification of Bacillus anthracis Lethal Factor

    Microsoft Academic Search

    Stephen H. Leppla

    2000-01-01

    Bacillus anthracis lethal factor (LF) is a 90-kDa zinc metalloprotease that plays an important role in the virulence of the organism. LF has previously been purified from Escherichia coli and Bacillus anthracis. The yields and purities of these preparations were inadequate for crystal structure determination. In this study, the genes encoding wild-type LF and a mutated, inactive LF (LF-E687C) were

  3. EXCALIBIR - A space experiment in orbital debris lethality

    Microsoft Academic Search

    Robert D. Culp; Michael R. Dickey

    1991-01-01

    The study proposes a space experiment using extended Space Shuttle external tanks to test the impact of orbital debris. The External Tank Calibrated Impact Response test, EXCALIBIR, is a low-cost low-risk, high-payoff approach to investigating the threat to resident space objects posed by untrackable orbital debris, to provide lethality data to the kinetic energy weapons community, and to aid in

  4. A genetic screen for high copy number suppressors of the synthetic lethality between elg1? and srs2? in yeast.

    PubMed

    Gazy, Inbal; Liefshitz, Batia; Bronstein, Alex; Parnas, Oren; Atias, Nir; Sharan, Roded; Kupiec, Martin

    2013-05-01

    Elg1 and Srs2 are two proteins involved in maintaining genome stability in yeast. After DNA damage, the homotrimeric clamp PCNA, which provides stability and processivity to DNA polymerases and serves as a docking platform for DNA repair enzymes, undergoes modification by the ubiquitin-like molecule SUMO. PCNA SUMOylation helps recruit Srs2 and Elg1 to the replication fork. In the absence of Elg1, both SUMOylated PCNA and Srs2 accumulate at the chromatin fraction, indicating that Elg1 is required for removing SUMOylated PCNA and Srs2 from DNA. Despite this interaction, which suggests that the two proteins work together, double mutants elg1? srs2? have severely impaired growth as haploids and exhibit synergistic sensitivity to DNA damage and a synergistic increase in gene conversion. In addition, diploid elg1? srs2? double mutants are dead, which implies that an essential function in the cell requires at least one of the two gene products for survival. To gain information about this essential function, we have carried out a high copy number suppressor screen to search for genes that, when overexpressed, suppress the synthetic lethality between elg1? and srs2?. We report the identification of 36 such genes, which are enriched for functions related to DNA- and chromatin-binding, chromatin packaging and modification, and mRNA export from the nucleus. PMID:23704284

  5. Synthetic lethality in the tobacco plastid ribosome and its rescue at elevated growth temperatures.

    PubMed

    Ehrnthaler, Miriam; Scharff, Lars B; Fleischmann, Tobias T; Hasse, Claudia; Ruf, Stephanie; Bock, Ralph

    2014-02-01

    Consistent with their origin from cyanobacteria, plastids (chloroplasts) perform protein biosynthesis on bacterial-type 70S ribosomes. The plastid genomes of seed plants contain a conserved set of ribosomal protein genes. Three of these have proven to be nonessential for translation and, thus, for cellular viability: rps15, rpl33, and rpl36. To help define the minimum ribosome, here, we examined whether more than one of these nonessential plastid ribosomal proteins can be removed from the 70S ribosome. To that end, we constructed all possible double knockouts for the S15, L33, and L36 ribosomal proteins by stable transformation of the tobacco (Nicotiana tabacum) plastid genome. We find that, although S15 and L33 function in different ribosomal particles (30S and 50S, respectively), their combined deletion from the plastid genome results in synthetic lethality under autotrophic conditions. Interestingly, the lethality can be overcome by growth under elevated temperatures due to an improved efficiency of plastid ribosome biogenesis. Our results reveal functional interactions between protein and RNA components of the 70S ribosome and uncover the interdependence of the biogenesis of the two ribosomal subunits. In addition, our findings suggest that defining a minimal set of plastid genes may prove more complex than generally believed. PMID:24563204

  6. Differential repair of potentially lethal damage in exponentially growing and quiescent 9L cells

    SciTech Connect

    Mendonca, M.S.; Rodriguez, A.; Alpen, E.L. (Lawrence Berkeley Laboratory, Berkeley (USA))

    1990-04-01

    The alteration of potentially lethal damage repair by postirradiation treatment with hypertonic saline (0.5 M PBS) was investigated in exponentially growing and quiescent 9L cells in vitro. A single dose of X rays (8.5 Gy) immediately followed by a 30-min treatment with hypertonic PBS at 37 degrees C reduced the survival of exponentially growing 9L cells by a factor of 13-18 compared to survival of irradiated immediately and delayed-plated cells, while the survival of quiescent cells was reduced by only a factor of 5-8. Survival curves confirmed the relative resistance of the quiescent 9L cells versus exponentially growing 9L cells to X rays plus hypertonic treatment. Both the slope and the shoulder of the survival curve were reduced to a greater extent in exponentially growing cells than in the quiescent cells by hypertonic treatment. The response of quiescent cells cannot be explained by either the duration of hypertonic treatment or the redistribution of the cells into G1 phase. We show that quiescent 9L cells can recover from hypertonically induced potentially lethal damage when incubated under conditions which have been found to delay progression through the cell cycle, and postulate that an altered chromatin structure or an enhanced repair capacity of quiescent 9L cells may be responsible for their resistance.

  7. Severe Hypoglycemia–Induced Lethal Cardiac Arrhythmias Are Mediated by Sympathoadrenal Activation

    PubMed Central

    Reno, Candace M.; Daphna-Iken, Dorit; Chen, Y. Stefanie; VanderWeele, Jennifer; Jethi, Krishan; Fisher, Simon J.

    2013-01-01

    For people with insulin-treated diabetes, severe hypoglycemia can be lethal, though potential mechanisms involved are poorly understood. To investigate how severe hypoglycemia can be fatal, hyperinsulinemic, severe hypoglycemic (10–15 mg/dL) clamps were performed in Sprague-Dawley rats with simultaneous electrocardiogram monitoring. With goals of reducing hypoglycemia-induced mortality, the hypotheses tested were that: 1) antecedent glycemic control impacts mortality associated with severe hypoglycemia; 2) with limitation of hypokalemia, potassium supplementation could limit hypoglycemia-associated deaths; 3) with prevention of central neuroglycopenia, brain glucose infusion could prevent hypoglycemia-associated arrhythmias and deaths; and 4) with limitation of sympathoadrenal activation, adrenergic blockers could prevent hypoglycemia-induced arrhythmic deaths. Severe hypoglycemia–induced mortality was noted to be worsened by diabetes, but recurrent antecedent hypoglycemia markedly improved the ability to survive an episode of severe hypoglycemia. Potassium supplementation tended to reduce mortality. Severe hypoglycemia caused numerous cardiac arrhythmias including premature ventricular contractions, tachycardia, and high-degree heart block. Intracerebroventricular glucose infusion reduced severe hypoglycemia–induced arrhythmias and overall mortality. ?-Adrenergic blockade markedly reduced cardiac arrhythmias and completely abrogated deaths due to severe hypoglycemia. Under conditions studied, sudden deaths caused by insulin-induced severe hypoglycemia were mediated by lethal cardiac arrhythmias triggered by brain neuroglycopenia and the marked sympathoadrenal response. PMID:23835337

  8. Intact alternation performance in high lethality suicide attempters.

    PubMed

    Keilp, John G; Wyatt, Gwinne; Gorlyn, Marianne; Oquendo, Maria A; Burke, Ainsley K; John Mann, J

    2014-09-30

    Suicide attempters often perform poorly on tasks linked to ventral prefrontal cortical (VPFC) function. Object Alternation (OA) - a VPFC probe - has not been used in these studies. In this study, currently depressed medication-free past suicide attempters whose most severe attempt was of high (n=31) vs. low (n=64) lethality, 114 medication-free depressed non-attempters, and 86 non-patients completed a computerized OA task. Participants also completed comparison tasks assessing the discriminant validity of OA (Wisconsin Card Sort), its concurrent validity relative to tasks associated with past attempt status (computerized Stroop task, Buschke Selective Reminding Test), and its construct validity as a VPFC measure (Go-No Go and Iowa Gambling Task). Against expectations, high lethality suicide attempters - the majority of whom used non-violent methods in their attempts with some planning - outperformed other depressed groups on OA, with no group differences observed on Wisconsin Card Sort. Despite intact performance on OA, past attempters exhibited deficits on the Stroop and Buschke. OA performance was associated with performance on Go-No Go and Iowa Gambling, confirming that OA measures a similar construct. VPFC dysfunction may not be a characteristic of all suicide attempters, especially those who make more carefully planned, non-violent - though potentially lethal - attempts. PMID:24878299

  9. Cold shock lethality and injury in Clostridium perfringens.

    PubMed

    Traci, P A; Duncan, C L

    1974-11-01

    Several observations have been made in regard to cold shock lethality of Clostridium perfringens: (i) loss of viability was not consequence of exposure of the cells to air; (ii) stationary-phase cells were much more resistant to cold shock at 4 C than exponential-phase cells; (iii) at 4 C 96% of an initial population of exponential-phase cells was killed upon cold shock and 95% of the remaining population was killed within 90 min of continued exposure at 4 C; (iv) the minimal temperature differential for detectable cold shock lethality was between 17 and 23 C, and the maximum beyond which lethality was not appreciably increased was between 28 and 33 C. Up to 75% of viable cold-shocked cells were injured, as demonstrated by cold shocking late exponential-phase cells at 10 C and using differential plating procedure for recovery. Repair of injury was temperature dependent, and occurred in a complex medium and 0.1% peptone but not water. Nalidixic acid, chloramphenicol, and rifampin did not inhibit repair of injury. PMID:4374121

  10. Anthrax lethal toxin: a weapon of multisystem destruction.

    PubMed

    Agrawal, A; Pulendran, B

    2004-11-01

    Lethal toxin (LT) is a major virulence factor secreted by anthrax bacteria. It is composed of two proteins, PA (protective antigen) and LF (lethal factor). PA transports the LF inside the cell, where LF, a zinc-dependent metalloprotease cleaves the mitogen activated protein kinase kinase (MAPKK) enzymes of the mitogen activated protein kinase (MAPK) signaling pathway, thereby impairing their function. This disruption of the MAPK pathway, which serves essential functions such as proliferation, survival and inflammation in all cell types, results in multisystem dysfunction in the host. The inactivation of the MAPK pathway in both macrophages and dendritic cells leads to inhibition of proinflammatory cytokine secretion, downregulation of costimulatory molecules such as CD80 and CD86, and ineffective T cell priming. The net result is an impaired innate and adaptive immune response. Endothelial cells of the vascular system undergo apoptosis upon LT exposure, also likely due to inactivation of the MAPK pathway. The activity of various hormone receptors such as glucocorticoids, progesterone and estrogen is also blocked, due to inhibition of p38 MAPK phosphorylation, thus affecting the body's response to stress. The present review summarizes the various disarming effects of Bacillus anthracis through the use of a single weapon, the lethal toxin. PMID:15558214

  11. Genetic and Phenotypic Analysis of Flagellar Assembly Mutants in Chlamydomonas reinhardtii

    PubMed Central

    Iomini, Carlo; Till, Jacob E.; Dutcher, Susan K.

    2013-01-01

    Conditional mutants for flagellar assembly (fla) provide a useful tool to study intraflagellar transport (IFT) at the molecular level, and provide a unique set of tools to analyze cilia. The analysis of IFT phenotypes of fla mutants at the permissive temperature by a quantitative image analysis approach identified four distinct phases of the IFT cycle and directly demonstrated structural and functional remodeling of IFT particles at both axonemal extremities. In addition, the genetic analysis of fla mutants reveal interesting interactions among genes involved in flagellar assembly that help to provide information about the structure and function of IFT particles and their motors. This chapter provides protocols to isolate, characterize, and identify conditional Chlamydomonas flagellar assembly mutants and their genes and to test genetic interactions among proteins encoded by these genes. PMID:20409815

  12. Mutant p53 cooperates with the SWI/SNF chromatin remodeling complex to regulate VEGFR2 in breast cancer cells.

    PubMed

    Pfister, Neil T; Fomin, Vitalay; Regunath, Kausik; Zhou, Jeffrey Y; Zhou, Wen; Silwal-Pandit, Laxmi; Freed-Pastor, William A; Laptenko, Oleg; Neo, Suat Peng; Bargonetti, Jill; Hoque, Mainul; Tian, Bin; Gunaratne, Jayantha; Engebraaten, Olav; Manley, James L; Børresen-Dale, Anne-Lise; Neilsen, Paul M; Prives, Carol

    2015-06-15

    Mutant p53 impacts the expression of numerous genes at the level of transcription to mediate oncogenesis. We identified vascular endothelial growth factor receptor 2 (VEGFR2), the primary functional VEGF receptor that mediates endothelial cell vascularization, as a mutant p53 transcriptional target in multiple breast cancer cell lines. Up-regulation of VEGFR2 mediates the role of mutant p53 in increasing cellular growth in two-dimensional (2D) and three-dimensional (3D) culture conditions. Mutant p53 binds near the VEGFR2 promoter transcriptional start site and plays a role in maintaining an open conformation at that location. Relatedly, mutant p53 interacts with the SWI/SNF complex, which is required for remodeling the VEGFR2 promoter. By both querying individual genes regulated by mutant p53 and performing RNA sequencing, the results indicate that >40% of all mutant p53-regulated gene expression is mediated by SWI/SNF. We surmise that mutant p53 impacts transcription of VEGFR2 as well as myriad other genes by promoter remodeling through interaction with and likely regulation of the SWI/SNF chromatin remodeling complex. Therefore, not only might mutant p53-expressing tumors be susceptible to anti VEGF therapies, impacting SWI/SNF tumor suppressor function in mutant p53 tumors may also have therapeutic potential. PMID:26080815

  13. p53 constrains progression to anaplastic thyroid carcinoma in a Braf-mutant mouse model of papillary thyroid cancer

    PubMed Central

    McFadden, David G.; Vernon, Amanda; Santiago, Philip M.; Martinez-McFaline, Raul; Bhutkar, Arjun; Crowley, Denise M.; McMahon, Martin; Sadow, Peter M.; Jacks, Tyler

    2014-01-01

    Anaplastic thyroid carcinoma (ATC) has among the worst prognoses of any solid malignancy. The low incidence of the disease has in part precluded systematic clinical trials and tissue collection, and there has been little progress in developing effective therapies. v-raf murine sarcoma viral oncogene homolog B (BRAF) and tumor protein p53 (TP53) mutations cooccur in a high proportion of ATCs, particularly those associated with a precursor papillary thyroid carcinoma (PTC). To develop an adult-onset model of BRAF-mutant ATC, we generated a thyroid-specific CreER transgenic mouse. We used a Cre-regulated BrafV600E mouse and a conditional Trp53 allelic series to demonstrate that p53 constrains progression from PTC to ATC. Gene expression and immunohistochemical analyses of murine tumors identified the cardinal features of human ATC including loss of differentiation, local invasion, distant metastasis, and rapid lethality. We used small-animal ultrasound imaging to monitor autochthonous tumors and showed that treatment with the selective BRAF inhibitor PLX4720 improved survival but did not lead to tumor regression or suppress signaling through the MAPK pathway. The combination of PLX4720 and the mapk/Erk kinase (MEK) inhibitor PD0325901 more completely suppressed MAPK pathway activation in mouse and human ATC cell lines and improved the structural response and survival of ATC-bearing animals. This model expands the limited repertoire of autochthonous models of clinically aggressive thyroid cancer, and these data suggest that small-molecule MAPK pathway inhibitors hold clinical promise in the treatment of advanced thyroid carcinoma. PMID:24711431

  14. Analysis of Escherichia coli mutants with a linear respiratory chain.

    PubMed

    Steinsiek, Sonja; Stagge, Stefan; Bettenbrock, Katja

    2014-01-01

    The respiratory chain of E. coli is branched to allow the cells' flexibility to deal with changing environmental conditions. It consists of the NADH:ubiquinone oxidoreductases NADH dehydrogenase I and II, as well as of three terminal oxidases. They differ with respect to energetic efficiency (proton translocation) and their affinity to the different quinone/quinol species and oxygen. In order to analyze the advantages of the branched electron transport chain over a linear one and to assess how usage of the different terminal oxidases determines growth behavior at varying oxygen concentrations, a set of isogenic mutant strains was created, which lack NADH dehydrogenase I as well as two of the terminal oxidases, resulting in strains with a linear respiratory chain. These strains were analyzed in glucose-limited chemostat experiments with defined oxygen supply, adjusting aerobic, anaerobic and different microaerobic conditions. In contrast to the wild-type strain MG1655, the mutant strains produced acetate even under aerobic conditions. Strain TBE032, lacking NADH dehydrogenase I and expressing cytochrome bd-II as sole terminal oxidase, showed the highest acetate formation rate under aerobic conditions. This supports the idea that cytochrome bd-II terminal oxidase is not able to catalyze the efficient oxidation of the quinol pool at higher oxygen conditions, but is functioning mainly under limiting oxygen conditions. Phosphorylation of ArcA, the regulator of the two-component system ArcBA, besides Fnr the main transcription factor for the response towards different oxygen concentrations, was studied. Its phosphorylation pattern was changed in the mutant strains. Dephosphorylation and therefore inactivation of ArcA started at lower aerobiosis levels than in the wild-type strain. Notably, not only the micro- and aerobic metabolism was affected by the mutations, but also the anaerobic metabolism, where the respiratory chain should not be important. PMID:24475268

  15. Lack of dominant lethality in mice following 1-bromopropane treatment.

    PubMed

    Yu, Wook-Joon; Kim, Jong-Choon; Chung, Moon-Koo

    2008-03-29

    1-Bromopropane (1-BP) is widely used in spray adhesives, precision cleaner, and degreaser. This study was conducted to investigate the potential of 1-BP to induce dominant lethality in mice. 1-BP was orally administered to males at doses of 300 and 600 mg/kg for 10 days before mating. Cyclophosphamide was used as a positive control (PC), which was administered intraperitoneally to males at 40 mg/kg for 5 days. The vehicle control (VC) group received corn oil only. Thereafter, males were mated with untreated females during six sequential mating periods of a week each. Males were sacrificed at the end of mating and so were the pregnant females on days 15-17 of gestation. Clinical signs, gross findings, mating index, gestation index, the numbers of corpora lutea, implantations, live fetuses, resorptions and dead fetuses, pre- and post-implantation losses, and dominant lethal mutation rate were examined. There were no treatment-related changes in clinical signs, gross findings, mating index, gestation index, number of corpora lutea and implantations, pre-implantation loss, live fetuses, resorptions, dead fetuses, post-implantation loss at any 1-BP doses tested. In the PC group, there were no treatment-related changes in mating index, gestation index, number of corpora lutea, and dead fetuses. However, a decrease in the number of implantations and an increase in pre-implantation loss were observed during the first 2 weeks as compared to those of the VC group. No treatment-related changes were observed in the third to sixth weeks. Increases in resorptions, fetal deaths and post-implantation loss, and a decrease in the number of live fetuses were observed in the first 3 weeks of the PC group compared to those of the VC group. However, no treatment-related changes were observed during the forth to sixth weeks. An increase in dominant lethal mutation rate was observed in 1-3 weeks of mating of the PC group, but there was no significant difference in 1-6 weeks of mating of the 1-BP treatment groups. In conclusion, 1-BP did not induce dominant lethality in mice. These results are in agreement with the report of Saito-Suzuki et al., demonstrating that no dominant lethality of 1-BP was observed in Sprague-Dawley rats. PMID:18291709

  16. LKTA DELETION MUTANT OF PASTEURELLA HAEMOLYTICA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Mutants of Pasteurella haemolytica provide excellent safety and efficacy when used as vaccines in ruminants, for example cattle, sheep and goats, subject to pneumonic pasteurellosis. They can be administered by a variety of routes. Especially preferred is the use in animal feeds. The mutants are ...

  17. A halotolerant mutant of Saccharomyces cerevisiae.

    PubMed Central

    Gaxiola, R; Corona, M; Zinker, S

    1996-01-01

    FRD, a nuclear and dominant spontaneous mutant of Saccharomyces cerevisiae capable of growing in up to 2 M NaCl, was isolated. Compared with parental cells, the mutant cells have a lower intracellular Na+/K+ ratio, shorter generation times in the presence of 1 M NaCl, and alterations in gene expression. PMID:8631691

  18. MAPPING EXPERIMENTS WITH r MUTANTS OF BACTERIOPHAGE

    E-print Network

    Klein, Stanley

    for crosses and preparation of phage stocks is given by STEINBERGand EDGAR(1962). The rI mutant, r48 r mutants of phage T4 fall into three clusters, each of which is essentially unlinked to the others. Since there is one cluster in each of the three so-calledlinkage groups, we will refer to the clusters

  19. Red Mutant Hunt with Saccharomyces cerevisiae

    NSDL National Science Digital Library

    Brad Williamson (Olathe East High School; )

    1999-01-01

    In this laboratory exercise, haploid yeast are exposed to UV radiation (UV-C) to induce mutations. Survivors are screened for red adenie mutants when characterized for nutritional requirements. Mutants produced in both mating types are crossed to determine inheritance patterns.

  20. Initial characterization of a pea mutant with light-independent photomorphogenesis.

    PubMed Central

    Frances, S; White, M J; Edgerton, M D; Jones, A M; Elliott, R C; Thompson, W F

    1992-01-01

    We have identified a mutant of pea cultivar Alaska that has many of the characteristics normally associated with light-grown seedlings even when grown in complete darkness. We have designated this mutant lip1, for light independent photomorphogenesis. Etiolated wild-type pea seedlings are white to slightly yellow in color and have a distinct morphology characterized by elongated epicotyls and buds containing unexpanded leaves with small, undifferentiated cells. In contrast, mutant seedlings grown under the same conditions are yellow in color and have short epicotyls and expanded leaves showing clear cellular differentiation. Transmission electron microscopy revealed partially developed, agranal plastids in the dark-grown mutant, unlike wild-type seedlings that contain etioplasts with prolamellar bodies. The mutant also exhibits a much shorter lag period for chlorophyll accumulation when etiolated seedlings are transferred from darkness to white light. The dark-grown mutant has 10-fold less spectrally detectable phytochrome, which can be attributed to a 10-fold reduction in the level of the PHYA polypeptide. Cab, Fed1, and RbcS transcripts are present in dark-grown mutant seedlings at levels comparable to those produced in light-grown material. The levels of these transcripts show a normal decrease when green plants grown for 15 days in a light/dark cycle are transferred to continuous darkness. However, transcript levels remain high during dark treatment of seedlings grown for 9 days in continuous light, indicating that the dark adaptation response in this mutant is developmentally plastic. The lip1 mutant has several features in common with the deetiolated Arabidopsis mutants det1, det2, and cop1. However, there are also several important differences, including varying effects on phytochrome levels, organ-specific gene expression, plastid development, and response to dark adaptation. PMID:1467651

  1. Highly variable recessive lethal or nearly lethal mutation rates during germ-line development of male Drosophila melanogaster

    PubMed Central

    Gao, Jian-Jun; Pan, Xue-Rong; Hu, Jing; Ma, Li; Wu, Jian-Min; Shao, Ye-Lin; Barton, Sara A.; Woodruff, Ronny C.; Zhang, Ya-Ping; Fu, Yun-Xin

    2011-01-01

    Each cell of higher organism adults is derived from a fertilized egg through a series of divisions, during which mutations can occur. Both the rate and timing of mutations can have profound impacts on both the individual and the population, because mutations that occur at early cell divisions will affect more tissues and are more likely to be transferred to the next generation. Using large-scale multigeneration screening experiments for recessive lethal or nearly lethal mutations of Drosophila melanogaster and recently developed statistical analysis, we show for male D. melanogaster that (i) mutation rates (for recessive lethal or nearly lethal) are highly variable during germ cell development; (ii) first cell cleavage has the highest mutation rate, which drops substantially in the second cleavage or the next few cleavages; (iii) the intermediate stages, after a few cleavages to right before spermatogenesis, have at least an order of magnitude smaller mutation rate; and (iv) spermatogenesis also harbors a fairly high mutation rate. Because germ-line lineage shares some (early) cell divisions with somatic cell lineage, the first conclusion is readily extended to a somatic cell lineage. It is conceivable that the first conclusion is true for most (if not all) higher organisms, whereas the other three conclusions are widely applicable, although the extent may differ from species to species. Therefore, conclusions or analyses that are based on equal mutation rates during development should be taken with caution. Furthermore, the statistical approach developed can be adopted for studying other organisms, including the human germ-line or somatic mutational patterns. PMID:21890796

  2. Transposon Insertions Causing Constitutive Sex-Lethal Activity in Drosophila Melanogaster Affect Sxl Sex-Specific Transcript Splicing

    PubMed Central

    Bernstein, M.; Lersch, R. A.; Subrahmanyan, L.; Cline, T. W.

    1995-01-01

    Sex-lethal (Sxl) gene products induce female development in Drosophila melanogaster and suppress the transcriptional hyperactivation of X-linked genes responsible for male X-chromosome dosage compensation. Control of Sxl functioning by the dose of X-chromosomes normally ensures that the female-specific functions of this developmental switch gene are only expressed in diplo-X individuals. Although the immediate effect of X-chromosome dose is on Sxl transcription, during most of the life cycle ``on'' vs. ``off'' reflects alternative Sxl RNA splicing, with the female (productive) splicing mode maintained by a positive feedback activity of SXL protein on Sxl pre-mRNA splicing. ``Male-lethal'' (Sxl(M)) gain-of-function alleles subvert Sxl control by X-chromosome dose, allowing female Sxl functions to be expressed independent of the positive regulators upstream of Sxl. As a consequence, Sxl(M) haplo-X animals (chromosomal males) die because of improper dosage compensation, and Sxl(M) chromosomal females survive the otherwise lethal effects of mutations in upstream positive regulators. Five independent spontaneous Sxl(M) alleles were shown previously to be transposon insertions into what was subsequently found to be the region of regulated sex-specific Sxl RNA splicing. We show that these five alleles represent three different mutant types: Sxl(M1), Sxl(M3), and Sxl(M4). Sxl(M1) is an insertion of a roo element 674 bp downstream of the translation-terminating male-specific exon. Sxl(M3) is an insertion of a hobo transposon (not 297 as previously reported) into the 3' splice site of the male exon, and Sxl(M4) is an insertion of a novel transposon into the male-specific exon itself. We show that these three gain-of-function mutants differ considerably in their ability to bypass the sex determination signal, with Sxl(M4) being the strongest and Sxl(M1) the weakest. This difference is also reflected in effects of these mutations on sex-specific RNA splicing and on the rate of appearance of SXL protein in male embryos. Transcript analysis of double-mutant male-viable Sxl(M) derivatives in which the Sxl(M) insertion is cis to loss-of-function mutations, combined with other results reported here, indicates that the constitutive character of these Sxl(M) alleles is a consequence of an alteration of the structure of the pre-mRNA that allows some level of female splicing to occur even in the absence of functional SXL protein. Surprisingly, however, most of the constitutive character of Sxl(M) alleles appears to depend on the mutant alleles' responsiveness, perhaps greater than wild-type, to the autoregulatory splicing activity of the wild-type SXL proteins they produce. PMID:7713421

  3. Differential Effects of Sex-Lethal Mutations on Dosage Compensation Early in Drosophila Development

    PubMed Central

    Bernstein, M.; Cline, T. W.

    1994-01-01

    In response to the primary sex determination signal, X chromosome dose, the Sex-lethal gene controls all aspects of somatic sex determination and differentiation, including X chromosome dosage compensation. Two complementary classes of mutations have been identified that differentially affect Sxl somatic functions: (1) those impairing the ``early'' function used to set developmental pathway choice in response to the sex determination signal and (2) those impairing ``late'' functions involved in maintaining the pathway choice independent of the initiating signal and/or in directing differentiation. This ``early vs. late'' distinction correlates with a switch in promoter utilization from Sxl(Pe) to Sxl(Pm) at the blastoderm stage and a corresponding switch from transcriptional to RNA splicing control. Here we characterize five partial-loss-of-function Sxl alleles to explore a distinction between ``early vs. late'' functioning of Sxl in dosage compensation. Assaying for dosage compensation during the blastoderm stage, we find that the earliest phase of the dosage compensation process is controlled by products of the early Sxl promoter, Sxl(Pe). Hence, in addition to triggering the sexual pathway decision of cells, products derived from Sxl(Pe) also control early dosage compensation, the first manifestation of sexually dimorphic differentiation. The effects of mutant Sxl alleles on early dosage compensation are consistent with their previous categorization as early vs. late defective with respect to their effects on pathway initiation. Results reported here suggest that the dosage compensation regulatory genes currently known to function downstream of Sxl, genes known as the ``male-specific lethals,'' do not control all aspects of dosage compensation either at the blastoderm stage or later in development. In the course of this study, we also discovered that the canonical early defective allele, Sxl(f9), which is impaired in its ability to establish the female developmental pathway commitment, is likely to be defective in the stability and/or functioning of products derived from Sxl(Pe), rather than in the ability of Sxl(Pe) to respond to the chromosomal sex determination signal. PMID:8005414

  4. Safety and protective efficacy of live attenuated Salmonella Gallinarum mutants in Rhode Island Red chickens.

    PubMed

    Mitra, Arindam; Loh, Amanda; Gonzales, Amanda; Laniewski, Pawe?; Willingham, Crystal; Curtiss Iii, Roy; Roland, Kenneth L

    2013-02-01

    Salmonella enterica serovar Gallinarum is the causative agent of fowl typhoid, an important systemic disease of poultry with economic consequences in developing nations. A live attenuated orally applied S. Gallinarum vaccine could provide a low cost method for controlling this disease. We constructed S. Gallinarum strains in which the expression of the crp, rfc and rfaH genes, important for virulence of Salmonella Typhimurium in mice, were under the control of an arabinose-regulated promoter. We evaluated the virulence of these strains compared to wild-type S. Gallinarum and to mutants carrying deletions in these genes. We found that rfc mutants were fully virulent, indicating that, unlike the S. Typhimurium mouse model, the rfc gene is dispensable in S. Gallinarum for virulence in birds. In the case of rfaH, the deletion mutant was attenuated and protective, while the strain with arabinose-regulated rfaH expression retained full virulence. The strain exhibiting arabinose-regulated crp expression was attenuated. Its virulence was not affected by the inclusion of 0.2% arabinose in the drinking water. Birds immunized with this strain were protected against a lethal S. Gallinarum challenge and against colonization with the human pathogen Salmonella Enteritidis. This work shows that an arabinose-regulated crp strain provides a basis for further development of a fowl typhoid vaccine. PMID:23261043

  5. Ultradian rhythm unmasked in the Pdf clock mutant of Drosophila.

    PubMed

    Seki, Yuuichi; Tanimura, Teiichi

    2014-09-01

    A diverse range of organisms shows physiological and behavioural rhythms with various periods. Extensive studies have been performed to elucidate the molecular mechanisms of circadian rhythms with an approximately 24 h period in both Drosophila and mammals, while less attention has been paid to ultradian rhythms with shorter periods. We used a video-tracking method to monitor the movement of single flies, and clear ultradian rhythms were detected in the locomotor behaviour of wild type and clock mutant flies kept under constant dark conditions. In particular, the Pigment-dispersing factor mutant (Pdf 01) demonstrated a precise and robust ultradian rhythmicity, which was not temperature compensated. Our results suggest that Drosophila has an endogenous ultradian oscillator that is masked by circadian rhythmic behaviours. PMID:25116613

  6. Characterization and RNA-seq analysis of underperformer, an activation-tagged potato mutant.

    PubMed

    Aulakh, Sukhwinder S; Veilleux, Richard E; Dickerman, Allan W; Tang, Guozhu; Flinn, Barry S

    2014-04-01

    The potato cv. Bintje and a Bintje activation-tagged mutant, underperformer (up) were compared. Mutant up plants grown in vitro were dwarf, with abundant axillary shoot growth, greater tuber yield, altered tuber traits and early senescence compared to wild type. Under in vivo conditions, the dwarf and early senescence phenotypes of the mutant remained, but the up plants exhibited a lower tuber yield and fewer axillary shoots compared to wild type. Southern blot analyses indicated a single T-DNA insertion in the mutant, located on chromosome 10. Initial PCR-based gene expression studies indicated transcriptional activation/repression of several genes in the mutant flanking the insertion. The gene immediately flanking the right border of the T-DNA insertion, which encoded an uncharacterized Broad complex, Tramtrac, Bric-a-brac; also known as Pox virus and Zinc finger (BTB/POZ) domain-containing protein (StBTB/POZ1) containing an Armadillo repeat region, was up-regulated in the mutant. Global gene expression comparisons between Bintje and up using RNA-seq on leaves from 60 day-old plants revealed a dataset of over 1,600 differentially expressed genes. Gene expression analyses suggested a variety of biological processes and pathways were modified in the mutant, including carbohydrate and lipid metabolism, cell division and cell cycle activity, biotic and abiotic stress responses, and proteolysis. PMID:24306493

  7. The effect of sexual harassment on lethal mutation rate in female Drosophila melanogaster

    PubMed Central

    Maklakov, Alexei A.; Immler, Simone; Løvlie, Hanne; Flis, Ilona; Friberg, Urban

    2013-01-01

    The rate by which new mutations are introduced into a population may have far-reaching implications for processes at the population level. Theory assumes that all individuals within a population have the same mutation rate, but this assumption may not be true. Compared with individuals in high condition, those in poor condition may have fewer resources available to invest in DNA repair, resulting in elevated mutation rates. Alternatively, environmentally induced stress can result in increased investment in DNA repair at the expense of reproduction. Here, we directly test whether sexual harassment by males, known to reduce female condition, affects female capacity to alleviate DNA damage in Drosophila melanogaster fruitflies. Female gametes can repair double-strand DNA breaks in sperm, which allows manipulating mutation rate independently from female condition. We show that male harassment strongly not only reduces female fecundity, but also reduces the yield of dominant lethal mutations, supporting the hypothesis that stressed organisms invest relatively more in repair mechanisms. We discuss our results in the light of previous research and suggest that social effects such as density and courtship can play an important and underappreciated role in mediating condition-dependent mutation rate. PMID:23173200

  8. The effect of sexual harassment on lethal mutation rate in female Drosophila melanogaster.

    PubMed

    Maklakov, Alexei A; Immler, Simone; Løvlie, Hanne; Flis, Ilona; Friberg, Urban

    2013-01-01

    The rate by which new mutations are introduced into a population may have far-reaching implications for processes at the population level. Theory assumes that all individuals within a population have the same mutation rate, but this assumption may not be true. Compared with individuals in high condition, those in poor condition may have fewer resources available to invest in DNA repair, resulting in elevated mutation rates. Alternatively, environmentally induced stress can result in increased investment in DNA repair at the expense of reproduction. Here, we directly test whether sexual harassment by males, known to reduce female condition, affects female capacity to alleviate DNA damage in Drosophila melanogaster fruitflies. Female gametes can repair double-strand DNA breaks in sperm, which allows manipulating mutation rate independently from female condition. We show that male harassment strongly not only reduces female fecundity, but also reduces the yield of dominant lethal mutations, supporting the hypothesis that stressed organisms invest relatively more in repair mechanisms. We discuss our results in the light of previous research and suggest that social effects such as density and courtship can play an important and underappreciated role in mediating condition-dependent mutation rate. PMID:23173200

  9. A new mouse mutant, skijumper.

    PubMed

    Hafezparast, Majid; Ball, Simon; Nicholson, Sharon J; Witherden, Abi; Arac, Demet; Broadway, Neil; Saggerson, David; Cooper, Edwin; Naase, Mahmoud; Gokhale, Stephen; Quant, Patti; Lascelles, Carol; Nickols, Carole; Baker, Cathy S; Peters, Josephine; Martin, Joanne E; Fisher, Elizabeth M C

    2002-07-01

    Low blood sugar levels are a well-known cause of severe illness and often death in newborn humans, especially those that are small for age. Few of the causes of neonatal hypoglycemia are known, and many remain to be found. We describe a novel mouse mutant, skijumper (skimp), in which pups, despite feeding well, have low levels of glucose and develop opisthotonos, followed by death typically within a few days after birth. Genetic mapping studies have localized the lesion to a approximately 1 cM interval on mouse Chromosome (Chr) 7 between D7Mit318 and D7Mit93. We have carried out extensive analysis to define the phenotype and its likely cause. In addition to low blood glucose, affected skijumper mice have lowglycogen and ketone levels. Mass spectrometric analysis of blood samples has excluded major defects in amino acid metabolism. Initial biochemical analyses suggested a defect in ketogenesis as one possible cause of this phenotype. However, measurements of levels and activities of carnitine, carnitine palmitoyl transferases, and other enzymes involved in ketogenesis, along with studies of mitochondrial structure and function, did not demonstrate significant differences between skijumper, unaffected littermates, and control wild-type mice. These results indicate that abnormal enzyme activity in known pathways does not appear to be the primary biochemical lesion in skijumper. The skijumper may be a new valuable model for studying and understanding one type of neonatal morbidity and death. PMID:12152619

  10. The Mutational Landscape of Lethal Castrate Resistant Prostate Cancer

    PubMed Central

    Grasso, Catherine S.; Wu, Yi-Mi; Robinson, Dan R.; Cao, Xuhong; Dhanasekaran, Saravana M.; Khan, Amjad P.; Quist, Michael J.; Jing, Xiaojun; Lonigro, Robert J.; Brenner, J. Chad; Asangani, Irfan A.; Ateeq, Bushra; Chun, Sang Y.; Siddiqui, Javed; Sam, Lee; Anstett, Matt; Mehra, Rohit; Prensner, John R.; Palanisamy, Nallasivam; Ryslik, Gregory A.; Vandin, Fabio; Raphael, Benjamin J.; Kunju, Lakshmi P.; Rhodes, Daniel R.; Pienta, Kenneth J.; Chinnaiyan, Arul M.; Tomlins, Scott A.

    2012-01-01

    Characterization of the prostate cancer transcriptome and genome has identified chromosomal rearrangements and copy number gains/losses, including ETS gene fusions, PTEN loss and androgen receptor (AR) amplification, that drive prostate cancer development and progression to lethal, metastatic castrate resistant prostate cancer (CRPC)1. As less is known about the role of mutations2–4, here we sequenced the exomes of 50 lethal, heavily-pretreated metastatic CRPCs obtained at rapid autopsy (including three different foci from the same patient) and 11 treatment naïve, high-grade localized prostate cancers. We identified low overall mutation rates even in heavily treated CRPC (2.00/Mb) and confirmed the monoclonal origin of lethal CRPC. Integrating exome copy number analysis identified disruptions of CHD1, which define a subtype of ETS fusionnegative prostate cancer. Similarly, we demonstrate that ETS2, which is deleted in ~1/3 of CRPCs (commonly through TMPRSS2:ERG fusions), is also deregulated through mutation. Further, we identified recurrent mutations in multiple chromatin/histone modifying genes, including MLL2 (mutated in 8.6% of prostate cancers), and demonstrate interaction of the MLL complex with AR, which is required for AR-mediated signaling. We also identified novel recurrent mutations in the AR collaborating factor FOXA1, which is mutated in 5 of 147 (3.4%) prostate cancers (both untreated localized prostate cancer and CRPC), and showed that mutated FOXA1 represses androgen signaling and increases tumour growth. Proteins that physically interact with AR, such as the ERG gene fusion product, FOXA1, MLL2, UTX, and ASXL1 were found to be mutated in CRPC. In summary, we describe the mutational landscape of a heavily treated metastatic cancer, identify novel mechanisms of AR signaling deregulated in prostate cancer, and prioritize candidates for future study. PMID:22722839

  11. Left ventricular function during lethal and sublethal endotoxemia in swine

    SciTech Connect

    Goldfarb, R.D.; Nightingale, L.M.; Kish, P.; Weber, P.B.; Loegering, D.J.

    1986-08-01

    Previous studies suggested that after a median lethal dose (LD50) of endotoxin, cardiac contractility was depressed in nonsurviving dogs. The canine cardiovascular system is unlike humans in that dogs have a hepatic vein sphincter that is susceptible to adrenergic stimulation capable of raising hepatic and splanchnic venous pressures. The authors retested the hypothesis that lethality after endotoxin administration is associated with cardiac contractile depression in pigs, because of the hepatic circulation in this species is similar to that of humans. They compared cardiac mechanical function of pigs administered a high dose (250 g/kg) or a low dose (100 g/kg) endotoxin by use of the slope of the end-systolic pressure-diameter relationship (ESPDR) as well as other measurements of cardiac performance. In all the pigs administered a high dose, ESPDR demonstrated a marked, time-dependent depression whereas we observed no significant ESPDR changes after low endotoxin doses. The other cardiodynamic variables were uninterpretable, due to the significant changes in heart rate, end-diastolic diameter (preload), and aortic diastolic pressure (afterload). Plasma myocardia depressant factor activity accumulated in all endotoxin-administered animals, tending to be greater in the high-dose group. In this group, both subendocardial blood flow and global function were depressed, whereas pigs administered the low dose endotoxin demonstrated slight, but nonsignificant, increases in flow and function. These observations indicate that myocardial contractile depression is associated with a lethal outcome to high doses of endotoxin. Myocardial perfusion was measured using radiolabeled microspheres infused into the left atria.

  12. Preparation and characterization of cobalt-substituted anthrax lethal factor

    SciTech Connect

    Saebel, Crystal E.; Carbone, Ryan; Dabous, John R.; Lo, Suet Y. [Department of Chemistry and Biochemistry, Laurentian University, 935 Ramsey Lake Rd., Sudbury, Ontario, Canada P3E 2C6 (Canada)] [Department of Chemistry and Biochemistry, Laurentian University, 935 Ramsey Lake Rd., Sudbury, Ontario, Canada P3E 2C6 (Canada); Siemann, Stefan, E-mail: ssiemann@laurentian.ca [Department of Chemistry and Biochemistry, Laurentian University, 935 Ramsey Lake Rd., Sudbury, Ontario, Canada P3E 2C6 (Canada)] [Department of Chemistry and Biochemistry, Laurentian University, 935 Ramsey Lake Rd., Sudbury, Ontario, Canada P3E 2C6 (Canada)

    2011-12-09

    Highlights: Black-Right-Pointing-Pointer Cobalt-substituted anthrax lethal factor (CoLF) is highly active. Black-Right-Pointing-Pointer CoLF can be prepared by bio-assimilation and direct exchange. Black-Right-Pointing-Pointer Lethal factor binds cobalt tightly. Black-Right-Pointing-Pointer The electronic spectrum of CoLF reveals penta-coordination. Black-Right-Pointing-Pointer Interaction of CoLF with thioglycolic acid follows a 2-step mechanism. -- Abstract: Anthrax lethal factor (LF) is a zinc-dependent endopeptidase involved in the cleavage of mitogen-activated protein kinase kinases near their N-termini. The current report concerns the preparation of cobalt-substituted LF (CoLF) and its characterization by electronic spectroscopy. Two strategies to produce CoLF were explored, including (i) a bio-assimilation approach involving the cultivation of LF-expressing Bacillus megaterium cells in the presence of CoCl{sub 2}, and (ii) direct exchange by treatment of zinc-LF with CoCl{sub 2}. Independent of the method employed, the protein was found to contain one Co{sup 2+} per LF molecule, and was shown to be twice as active as its native zinc counterpart. The electronic spectrum of CoLF suggests the Co{sup 2+} ion to be five-coordinate, an observation similar to that reported for other Co{sup 2+}-substituted gluzincins, but distinct from that documented for the crystal structure of native LF. Furthermore, spectroscopic studies following the exposure of CoLF to thioglycolic acid (TGA) revealed a sequential mechanism of metal removal from LF, which likely involves the formation of an enzyme: Co{sup 2+}:TGA ternary complex prior to demetallation of the active site. CoLF reported herein constitutes the first spectroscopic probe of LF's active site, which may be utilized in future studies to gain further insight into the enzyme's mechanism and inhibitor interactions.

  13. Both Loss-of-Function and Gain-of-Function Mutations in Snf Define a Role for Snrnp Proteins in Regulating Sex-Lethal Pre-mRNA Splicing in Drosophila Development

    PubMed Central

    Salz, H. K.; Flickinger, T. W.

    1996-01-01

    The Drosophila snf gene encodes a protein with functional homology to the mammalian U1A and U2B" snRNP proteins. Studies, based on the analysis of three viable alleles, have suggested a role for snf in establishing the female-specific splicing pattern of the sex determination switch gene, Sex-lethal. Here, we show that the non-sex-specific lethal null allele is required for female sex determination, arguing against the formal possibility that the viable alleles disrupt a function unrelated to snf's wild-type function. Moreover, we find snf is required for normal cell growth and/or survival, as expected for a protein involved in a cell-vital process such as RNA splicing. We also show that of the three viable alleles only one, snf(JA2), is a partial loss-of-function mutation. The other two viable alleles, snf(1621) and snf(e8H), encode antimorphic proteins. We find the antimorphic proteins are mislocalized and correlate their mislocalization with their molecular lesions and mutant phenotypes. Finally, we provide genetic evidence that the antimorphic alleles interfere with the autoregulatory splicing function of the Sex-lethal protein. Based on these studies we suggest a model in which the snRNP protein, Snf, functions with Sex-lethal to block recognition of the regulated male-specific exon. PMID:8878676

  14. Studies on the Chick-lethal Toxin of Escherichia coli

    PubMed Central

    Truscott, R. B.

    1973-01-01

    A toxin which is lethal for two week old chicks has been recovered from strains of Escherichia coli O78:K80 of bovine and avian origin and from avian isolates of serogroups O2, O45 and O109. The toxin is heat-labile, antigenic, high in protein, inactivated by pronase, trypsin, amylase, and pancreatic lipase. The toxin may be precipitated by ammonium sulfate or TCA treatment from the supernatant obtained by repeated centrifugation of sonicated cells. Considerable purification has been obtained by column chromatography using Sepharose 6B. PMID:4270809

  15. Ocular manifestations of the potentially lethal rheumatologic and vasculitic disorders.

    PubMed

    Foster, C Stephen

    2013-06-01

    Vision threatening ocular inflammation may occur in patients with any of the acquired connective tissue disorders and vasculitic diseases. Additionally, the ocular inflammation may be the presenting manifestation of the disease, which leads the patient to seek medical care. Other manifestations of the potentially lethal disease may be subtle or absent, presenting the thoughtful ophthalmologist with the opportunity to make life saving discoveries. Necrotizing scleritis, peripheral ulcerative keratitis, and retinal vasculitis are the ocular findings which should prompt the ophthalmologist to initiate very aggressive measures aimed at discovering any evidence of extra-ocular abnormalities, laboratory or otherwise. Appropriate therapy will be sight saving and may be life saving. PMID:23688612

  16. Proteinuria and Perinatal Lethality in Mice Lacking NEPH1, a Novel Protein with Homology to NEPHRIN

    PubMed Central

    Donoviel, Dorit B.; Freed, Deon D.; Vogel, Hannes; Potter, David G.; Hawkins, Edith; Barrish, James P.; Mathur, Brian N.; Turner, C. Alexander; Geske, Robert; Montgomery, Charles A.; Starbuck, Michael; Brandt, Mary; Gupta, Anupma; Ramirez-Solis, Ramiro; Zambrowicz, Brian P.; Powell, David R.

    2001-01-01

    A high-throughput, retrovirus-mediated mutagenesis method based on gene trapping in embryonic stem cells was used to identify a novel mouse gene. The human ortholog encodes a transmembrane protein containing five extracellular immunoglobulin-like domains that is structurally related to human NEPHRIN, a protein associated with congenital nephrotic syndrome. Northern analysis revealed wide expression in humans and mice, with highest expression in kidney. Based on similarity to NEPHRIN and abundant expression in kidney, this protein was designated NEPH1 and embryonic stem cells containing the retroviral insertion in the Neph1 locus were used to generate mutant mice. Analysis of kidney RNA from Neph1?/? mice showed that the retroviral insertion disrupted expression of Neph1 transcripts. Neph1?/? pups were represented at the expected normal Mendelian ratios at 1 to 3 days of age but at only 10% of the expected frequency at 10 to 12 days after birth, suggesting an early postnatal lethality. The Neph1?/? animals that survived beyond the first week of life were sickly and small but without edema, and all died between 3 and 8 weeks of age. Proteinuria ranging from 300 to 2,000 mg/dl was present in all Neph1?/? mice. Electron microscopy demonstrated NEPH1 expression in glomerular podocytes and revealed effacement of podocyte foot processes in Neph1?/? mice. These findings suggest that NEPH1, like NEPHRIN, may play an important role in maintaining the structure of the filtration barrier that prevents proteins from freely entering the glomerular urinary space. PMID:11416156

  17. A phenotype survey of 36 mutant mouse strains with gene-targeted defects in glycosyltransferases or glycan-binding proteins

    PubMed Central

    Orr, Sally L; Le, Dzung; Long, Jeffrey M; Sobieszczuk, Peter; Ma, Bo; Tian, Hua; Fang, Xiaoqun; Paulson, James C; Marth, Jamey D; Varki, Nissi

    2013-01-01

    The consortium for functional glycomics (CFG) was a large research initiative providing networking and resources for investigators studying the role of glycans and glycan-binding proteins in health and disease. Starting in 2001, six scientific cores were established to generate data, materials and new technologies. By the end of funding in 2011, the mouse phenotype core (MPC) submitted data to a website from the phenotype screen of 36 mutant mouse strains deficient in a gene for either a glycan-binding protein (GBP) or glycosyltransferase (GT). Each mutant strain was allotted three months for analysis and screened by standard phenotype assays used in the fields of immunology, histology, hematology, coagulation, serum chemistry, metabolism and behavior. Twenty of the deficient mouse strains had been studied in other laboratories, and additional tests were performed on these strains to confirm previous observations and discover new data. The CFG constructed 16 new homozygous mutant mouse strains and completed the initial phenotype screen of the majority of these new mutant strains. In total, >300 phenotype changes were observed, but considering the over 100 assays performed on each strain, most of the phenotypes were unchanged. Phenotype differences include abnormal testis morphology in GlcNAcT9- and Siglec-H-deficient mice and lethality in Pomgnt1-deficient mice. The numerous altered phenotypes discovered, along with the consideration of the significant findings of normality, will provide a platform for future characterization to understand the important roles of glycans and GBPs in the mechanisms of health and disease. PMID:23118208

  18. A new Adamts9 conditional mouse allele identifies its non-redundant role in interdigital web regression.

    PubMed

    Dubail, Johanne; Aramaki-Hattori, Noriko; Bader, Hannah L; Nelson, Courtney M; Katebi, Negin; Matuska, Brittany; Olsen, Bjorn R; Apte, Suneel S

    2014-07-01

    ADAMTS9 is the most conserved member of a large family of secreted metalloproteases having diverse functions. Adamts9 null mice die before gastrulation, precluding investigations of its roles later in embryogenesis, in adult mice or disease models. We therefore generated a floxed Adamts9 allele to bypass embryonic lethality. In this mutant, unidirectional loxP sites flank exons 5-8, which encode the catalytic domain, including the protease active site. Mice homozygous for the floxed allele were viable, lacked an overt phenotype, and were fertile. Conversely, mice homozygous for a germ-line deletion produced from the floxed allele by Cre-lox recombination did not survive past gastrulation. Hemizygosity of the deleted Adamts9 in combination with mutant Adamts20 led to cleft palate and severe white spotting as previously described. Previously, Adamts9 haploinsufficiency combined with either Adamts20 or Adamts5 nullizygosity suggested a cooperative role in interdigital web regression, but the outcome of deletion of Adamts9 alone remained unknown. Here, Adamts9 was conditionally deleted in limb mesoderm using Prx1-Cre mice. Unlike other ADAMTS single knockouts, limb-specific Adamts9 deletion resulted in soft-tissue syndactyly (STS) with 100% penetrance and concurrent deletion of Adamts5 increased the severity of STS. Thus, Adamts9 has both non-redundant and cooperative roles in ensuring interdigital web regression. This new allele will be useful for investigating other biological functions of ADAMTS9. PMID:24753090

  19. A new Adamts9 conditional mouse allele identifies its non-redundant role in interdigital web regression

    PubMed Central

    Dubail, Johanne; Aramaki-Hattori, Noriko; Bader, Hannah L.; Nelson, Courtney M.; Katebi, Negin; Matuska, Brittany; Olsen, Bjorn R.; Apte, Suneel S.

    2014-01-01

    ADAMTS9 is the most conserved member of a large family of secreted metalloproteases having diverse functions. Adamts9 null mice die before gastrulation, precluding investigations of its roles later in embryogenesis, in adult mice or disease models. We therefore generated a floxed Adamts9 allele to bypass embryonic lethality. In this mutant, unidirectional loxP sites flank exons 5 through 8, which encode the catalytic domain, including the protease active site. Mice homozygous for the floxed allele were viable, lacked an overt phenotype, and were fertile. Conversely, mice homozygous for a germ-line deletion produced from the floxed allele by Cre-lox recombination did not survive past gastrulation. Hemizygosity of the deleted Adamts9 in combination with mutant Adamts20 led to cleft palate and severe white spotting as previously described. Previously, Adamts9 haploinsufficiency combined with either Adamts20 or Adamts5 nullizygosity suggested a cooperative role in interdigital web regression, but the outcome of deletion of Adamts9 alone remained unknown. Here, Adamts9 was conditionally deleted in limb mesoderm using Prx1-Cre mice. Unlike other ADAMTS single knockouts, limb-specific Adamts9 deletion resulted in soft-tissue syndactyly (STS) with 100% penetrance and concurrent deletion of Adamts5 increased the severity of STS. Thus, Adamts9 has both non-redundant and cooperative roles in ensuring interdigital web regression. This new allele will be useful for investigating other biological functions of ADAMTS9. PMID:24753090

  20. In vitro and in vivo characterization of an ail mutant of Yersinia enterocolitica.

    PubMed Central

    Wachtel, M R; Miller, V L

    1995-01-01

    Ail is a 17-kDa protein of Yersinia enterocolitica previously identified on the basis of its ability to confer upon Escherichia coli the phenotype of attachment and invasion of cultured epithelial cells. Here we report an examination of the contribution of ail to the pathogenicity of Y. enterocolitica. A low-copy-number ail plasmid that promoted serum resistance in E. coli HB101 was constructed. The serum resistance phenotype conferred by ail to E. coli was affected by the growth phase of the culture as well as by the gene copy number. In contrast, the copy number of ail (and the relative quantity of Ail) was found to have little effect on the amount of Ail-promoted invasion of cultured epithelial cells. An ail mutant of Y. enterocolitica was constructed and characterized in vitro. This mutant produced no detectable Ail and had a reduced ability to invade CHO cells. Serum resistance of Y. enterocolitica was Ail dependent and was affected by growth phase and ail copy number. The phenotype of the ail mutant was examined in vivo by using a murine model for infection. The ail mutant phenotype was identical to that of the wild-type strain in oral 50% lethal dose studies and early colonization of Peyer's patches as well as in kinetic studies. Western blot (immunoblot) analysis of Ail produced by bacteria growing in vivo at 48 h postinfection indicated that ail was expressed at this time point. Thus, our findings confirm that Ail contributes to the serum resistance and invasion phenotypes of Y. enterocolitica in vitro and indicate that Ail is not required to establish an infection or to cause systemic infection of BALB/c or DBA/2 mice. PMID:7790067

  1. Characterization of two highly amyloidogenic mutants of transthyretin.

    PubMed

    Goldsteins, G; Andersson, K; Olofsson, A; Dacklin, I; Edvinsson, A; Baranov, V; Sandgren, O; Thylén, C; Hammarstrom, S; Lundgren, E

    1997-05-01

    The plasma protein transthyretin (TTR) has the potential to form amyloid under certain conditions. More than 50 different point mutations have been associated with amyloid formation that occurs only in adults. It is not known what structural changes are introduced into the structure of this otherwise stable molecule that results in its aggregation into insoluble amyloid fibrils. On the basis of calculations of the frequency of known mutations over the polypeptide, we have constructed two mutants in the D-strand of the polypeptide. These molecules, containing either a deletion or a substitution at amino acid positions 53-55, were unstable and spontaneously formed aggregates upon storage in TBS (pH 7.6). The precipitates were shown to be amyloid by staining with thioflavin T and Congo Red. Their ultrastructure was very similar to that of amyloid fibrils deposited in the vitreous body of patients with familial amyloidotic polyneuropathy type 1 with an amino acid replacement in position 30 (TTRmet30). Like amyloid isolated from the vitreous body of the eye, the amyloid precipitates generated from the TTR mutants exposed a trypsin cleavage site between amino acid residues 48 and 49, while plasma TTRmet30 isolated from amyloidosis patients as well as wild-type TTR only showed minor trypsin sensitivity. Our data indicate that the mutants we have constructed are similar to amyloid precursors or may share structural properties with intermediates on a pathway leading to amyloid deposits of plasma TTR. PMID:9154916

  2. High level of antibiotic production in a double polyphosphate kinase and phosphate-binding protein mutant of Streptomyces lividans.

    PubMed

    Díaz, Margarita; Sevillano, Laura; Rico, Sergio; Lombo, Felipe; Braña, Alfredo F; Salas, Jose A; Mendez, Carmen; Santamaría, Ramón I

    2013-05-01

    Phosphate metabolism regulates most of the life processes of microorganisms. In the present work we obtained and studied a Streptomyces lividans ppk/pstS double mutant, which lacks polyphosphate kinase (PPK) and the high-affinity phosphate-binding protein (PstS), impairing at the same time the intracellular storage of polyphosphate and the intake of new inorganic phosphate from a phosphate-limited medium, respectively. In some of the aspects analyzed, the ppk/pstS double mutant was more similar to the wt strain than was the single pstS mutant. The double mutant was thus able to grow in phosphate-limited media, whereas the pstS mutant required the addition of 1 mM phosphate under the assay conditions used. The double mutant was able to incorporate more than one fourth of the inorganic phosphate incorporated by the wt strain, whereas phosphate incorporation was almost completely impaired in the pstS mutant. Noteworthy, under phosphate limitation conditions, the double ppk/pstS mutant showed a higher production of the endogenous antibiotic actinorhodin and the heterologous antitumor 8-demethyl-tetracenomycin (up to 10-fold with respect to the wt strain), opening new possibilities for the use of this strain in the heterologous expression of antibiotic pathways. PMID:23398561

  3. Lethal body burdens of polar narcotic chemicals: Chlorophenols

    SciTech Connect

    Wezel, A. van; Punte, S.; Opperhuizen, A. [RITOX, Utrecht (Netherlands). Environmental Chemistry Group

    1994-12-31

    Lethal body burdens (LBBs) were measured of low chlorinated phenols to obtain insight in the intrinsic toxicity of these compounds and in the origins of differences in toxicity between polar and nonpolar narcotic chemicals. Fathead minnows were exposed until death to 2-chlorophenol, 4-chlorophenol or 2,4-chlorophenol at fixed pH. LBBs of chlorophenols were shown to be significantly lower than LBBs of the nonpolar chlorobenzenes. The pH of the exposure doesn`t influence the LBB of chlorophenols, whereas it does influence chemical speciation and thus the uptake and the LC50 of the chlorophenols. Octanol-water partition coefficients were measured at different pH, to gain insight in the distribution of the chlorophenols between aqueous and fatty compartments inside the organism. It is shown that at a physiological pH only a fraction of the total amount of chlorophenols inside the organism is accumulated in the fatty parts of the organism. These fatty parts, including the membranes, are usually considered as the target site for narcotic chemicals. It is concluded that the concentration at the membrane needed for lethality is lower for polar narcotic chemicals than for nonpolar narcotic chemicals, implying either a different mode of action at the same target site or another target site.

  4. Loss of Desmoplakin Tail Causes Lethal Acantholytic Epidermolysis Bullosa*

    PubMed Central

    Jonkman, Marcel F.; Pasmooij, Anna M. G.; Pasmans, Suzanne G. M. A.; van den Berg, Maarten P.; ter Horst, Henk J.; Timmer, Albertus; Pas, Hendri H.

    2005-01-01

    The cytoplasmic plaque protein desmoplakin (DP), which is located in desmosomes, plays a major role in epithelial and muscle cell adhesion by linking the transmembrane cadherins to the cytoplasmic intermediate filament network. Mutations of DP may cause striate palmoplantar keratoderma, arrhythmogenic right ventricular dysplasia, skin fragility/woolly hair syndrome, Naxos-like disease, and Carvajal syndrome. DP must be indispensable, because DP-/- mice are early abortive. Here, we report a patient with severe fragility of skin and mucous membranes caused by genetic truncation of the DP tail. The new phenotype is lethal in the neonatal period because of immense transcutaneous fluid loss. The phenotype also comprised universal alopecia, neonatal teeth, and nail loss. Histology showed suprabasal clefting and acantholysis throughout the spinous layer, mimicking pemphigus. Electron microscopy revealed disconnection of keratin intermediate filaments from desmosomes. Immunofluorescence staining of DP showed a distinct punctate intercellular pattern in the patient’s skin. Protein analysis revealed expression of truncated DP polypeptides. Mutational analysis of the patient demonstrated compound heterozygosity for two DP mutations, 6079C?T (R1934X) and 6370delTT, respectively. Aberrant mRNA transcripts that predict premature termination of translation with loss of the three intermediate filament-binding subdomains in the DP tail were detected by RT-PCR. The new dramatic phenotype, which we named “lethal acantholytic epidermolysis bullosa,” underscores the paramount role of DP in epidermal integrity. PMID:16175511

  5. An outbreak of lethal adenovirus infection among different otariid species.

    PubMed

    Inoshima, Yasuo; Murakami, Tomoaki; Ishiguro, Naotaka; Hasegawa, Kazuhiro; Kasamatsu, Masahiko

    2013-08-30

    An outbreak of fatal fulminant hepatitis at a Japanese aquarium involved 3 otariids: a California sea lion (Zalophus californianus), a South African fur seal (Arctocephalus pusillus) and a South American sea lion (Otaria flavescens). In a span of about a week in February 2012, 3 otariids showed diarrhea and were acutely low-spirited; subsequently, all three animals died within a period of 3 days. Markedly increased aspartate amino transferase and alanine amino transferase activities were observed. Necrotic hepatitis and eosinophilic intranuclear inclusion bodies in liver hepatocytes and intestinal epithelial cells were observed in the South American sea lion on histological examination. Otarine adenovirus DNA was detected from the livers of all three animals by polymerase chain reaction and determination of the sequences showed that all were identical. These results suggest that a single otarine adenovirus strain may have been the etiological agent of this outbreak of fatal fulminant hepatitis among the different otariid species, and it may be a lethal threat to wild and captive otariids. This is the first evidence of an outbreak of lethal adenovirus infection among different otariid species. PMID:23643878

  6. A virulent parasite can provide protection against a lethal parasitoid.

    PubMed

    Sternberg, Eleanore D; Lefèvre, Thierry; Rawstern, Amanda H; de Roode, Jacobus C

    2011-03-01

    Hosts often become infected with multiple parasite strains or species. Previous work has shown that the outcome of infections with multiple parasite strains or species often differs significantly from that of single infections, making them a potentially important factor in determining the prevalence and spread of disease. Here we show that infection with a virulent parasite increases host survival during later exposure to a lethal parasitoid. Specifically, when monarch butterfly larvae (Danaus plexippus) are inoculated with the virulent protozoan parasite Ophryocystis elektroscirrha and then attacked by the lethal parasitoid fly Lespesia archippivora, survival is higher than when the larvae are exposed to the parasitoid only. This is potentially a result of the protozoan's requirement for host survival to obtain between-host transmission. Our findings suggest that a virulent parasite can play a protective role for its host and indicate that parasites can act as mutualists depending on the presence of other parasites. We emphasize the importance of considering infection in an ecological context, including the presence of competing parasites. PMID:21145987

  7. Suppressive Effects of Anthrax Lethal Toxin on Megakaryopoiesis

    PubMed Central

    Lin, Guan-Ling; Wang, Tsung-Pao; Lai, Yi-Ling; Lin, Ting-Kai; Hsieh, Ming-Chun; Kau, Jyh-Hwa; Huang, Hsin-Hsien; Hsu, Hui-Ling; Liao, Chi-Yuan; Sun, Der-Shan

    2013-01-01

    Anthrax lethal toxin (LT) is a major virulence factor of Bacillus anthracis. LT challenge suppresses platelet counts and platelet function in mice, however, the mechanism responsible for thrombocytopenia remains unclear. LT inhibits cellular mitogen-activated protein kinases (MAPKs), which are vital pathways responsible for cell survival, differentiation, and maturation. One of the MAPKs, the MEK1/2-extracellular signal-regulated kinase pathway, is particularly important in megakaryopoiesis. This study evaluates the hypothesis that LT may suppress the progenitor cells of platelets, thereby inducing thrombocytopenic responses. Using cord blood-derived CD34+ cells and mouse bone marrow mononuclear cells to perform in vitro differentiation, this work shows that LT suppresses megakaryopoiesis by reducing the survival of megakaryocytes. Thrombopoietin treatments can reduce thrombocytopenia, megakaryocytic suppression, and the quick onset of lethality in LT-challenged mice. These results suggest that megakaryocytic suppression is one of the mechanisms by which LT induces thrombocytopenia. These findings may provide new insights for developing feasible approaches against anthrax. PMID:23555687

  8. Effectiveness of lethal, directed wolf-depredation control in Minnesota

    USGS Publications Warehouse

    Harper, E.K.; Paul, W.J.; Mech, L.D.; Weisberg, S.

    2008-01-01

    Wolf (Canis lupus) depredations on livestock in Minnesota, USA, are an economic problem for many livestock producers, and depredating wolves are lethally controlled. We sought to determine the effectiveness of lethal control through the analysis of data from 923 government-verified wolf depredations from 1979 to 1998. We analyzed the data by 1) assessing the correlations between the number of wolves killed in response to depredations with number of depredations the following year at state and local levels, and 2) the time to the next depredation. No analysis indicated that trapping wolves substantially reduced the following year's depredations at state or local levels. However, more specific analyses indicated that in certain situations, killing wolves was more effective than no action (i.e., not trapping). For example, trapping and killing adult males decreased the re-depredation risk. At sheep farms, killing wolves was generally effective. Attempting to trap, regardless of the results, seemed more effective at reducing depredations than not trapping, suggesting that mere human activity near depredation sites might deter future depredations.

  9. Injury Risk Assessment of Non-Lethal Projectile Head Impacts

    PubMed Central

    Oukara, Amar; Nsiampa, Nestor; Robbe, Cyril; Papy, Alexandre

    2014-01-01

    Kinetic energy non-lethal projectiles are used to impart sufficient effect onto a person in order to deter uncivil or hazardous behavior with a low probability of permanent injury. Since their first use, real cases indicate that the injuries inflicted by such projectiles may be irreversible and sometimes lead to death, especially for the head impacts. Given the high velocities and the low masses involved in such impacts, the assessment approaches proposed in automotive crash tests and sports may not be appropriate. Therefore, there is a need of a specific approach to assess the lethality of these projectiles. In this framework, some recent research data referred in this article as “force wall approach” suggest the use of three lesional thresholds (unconsciousness, meningeal damages and bone damages) that depend on the intracranial pressure. Three corresponding critical impact forces are determined for a reference projectile. Based on the principle that equal rigid wall maximal impact forces will produce equal damage on the head, these limits can be determined for any other projectile. In order to validate the consistence of this innovative method, it is necessary to compare the results with other existing assessment methods. This paper proposes a comparison between the “force wall approach” and two different head models. The first one is a numerical model (Strasbourg University Finite Element Head Model-SUFEHM) from Strasbourg University; the second one is a mechanical surrogate (Ballistics Load Sensing Headform-BLSH) from Biokinetics. PMID:25400712

  10. Injury risk assessment of non-lethal projectile head impacts.

    PubMed

    Oukara, Amar; Nsiampa, Nestor; Robbe, Cyril; Papy, Alexandre

    2014-01-01

    Kinetic energy non-lethal projectiles are used to impart sufficient effect onto a person in order to deter uncivil or hazardous behavior with a low probability of permanent injury. Since their first use, real cases indicate that the injuries inflicted by such projectiles may be irreversible and sometimes lead to death, especially for the head impacts. Given the high velocities and the low masses involved in such impacts, the assessment approaches proposed in automotive crash tests and sports may not be appropriate. Therefore, there is a need of a specific approach to assess the lethality of these projectiles. In this framework, some recent research data referred in this article as "force wall approach" suggest the use of three lesional thresholds (unconsciousness, meningeal damages and bone damages) that depend on the intracranial pressure. Three corresponding critical impact forces are determined for a reference projectile. Based on the principle that equal rigid wall maximal impact forces will produce equal damage on the head, these limits can be determined for any other projectile. In order to validate the consistence of this innovative method, it is necessary to compare the results with other existing assessment methods. This paper proposes a comparison between the "force wall approach" and two different head models. The first one is a numerical model (Strasbourg University Finite Element Head Model-SUFEHM) from Strasbourg University; the second one is a mechanical surrogate (Ballistics Load Sensing Headform-BLSH) from Biokinetics. PMID:25400712

  11. CSNK1E/CTNNB1 are synthetic lethal to TP53 in colorectal cancer and are markers for prognosis.

    PubMed

    Tiong, Khong-Loon; Chang, Kuo-Ching; Yeh, Kun-Tu; Liu, Ting-Yuan; Wu, Jia-Hong; Hsieh, Ping-Heng; Lin, Shu-Hui; Lai, Wei-Yun; Hsu, Yu-Chin; Chen, Jeou-Yuan; Chang, Jan-Gowth; Shieh, Grace S

    2014-05-01

    Two genes are called synthetic lethal (SL) if their simultaneous mutations lead to cell death, but each individual mutation does not. Targeting SL partners of mutated cancer genes can kill cancer cells specifically, but leave normal cells intact. We present an integrated approach to uncovering SL pairs in colorectal cancer (CRC). Screening verified SL pairs using microarray gene expression data of cancerous and normal tissues, we first identified potential functionally relevant (simultaneously differentially expressed) gene pairs. From the top-ranked pairs, ~20 genes were chosen for immunohistochemistry (IHC) staining in 171 CRC patients. To find novel SL pairs, all 169 combined pairs from the individual IHC were synergistically correlated to five clinicopathological features, e.g. overall survival. Of the 11 predicted SL pairs, MSH2-POLB and CSNK1E-MYC were consistent with literature, and we validated the top two pairs, CSNK1E-TP53 and CTNNB1-TP53 using RNAi knockdown and small molecule inhibitors of CSNK1E in isogenic HCT-116 and RKO cells. Furthermore, synthetic lethality of CSNK1E and TP53 was verified in mouse model. Importantly, multivariate analysis revealed that CSNK1E-P53, CTNNB1-P53, MSH2-RB1, and BRCA1-WNT5A were independent prognosis markers from stage, with CSNK1E-P53 applicable to early-stage and the remaining three throughout all stages. Our findings suggest that CSNK1E is a promising target for TP53-mutant CRC patients which constitute ~40% to 50% of patients, while to date safety regarding inhibition of TP53 is controversial. Thus the integrated approach is useful in finding novel SL pairs for cancer therapeutics, and it is readily accessible and applicable to other cancers. PMID:24947187

  12. Impulsivity, aggression and brain structure in high and low lethality suicide attempters with borderline personality disorder

    PubMed Central

    Soloff, Paul; White, Richard; Diwadkar, Vaibhav A.

    2014-01-01

    Impulsivity and aggressiveness are trait dispositions associated with the vulnerability to suicidal behavior across diagnoses. They are associated with structural and functional abnormalities in brain networks involved in regulation of mood, impulse and behavior. They are also core characteristics of borderline personality disorder (BPD), a disorder defined, in part, by recurrent suicidal behavior. We assessed the relationships between personality traits, brain structure and lethality of suicide attempts in 51 BPD attempters using multiple regression analyses on structural MRI data. BPD was diagnosed by the Diagnostic Interview for Borderline Patients-revised, impulsivity by the Barratt Impulsiveness Scale (BIS), aggression by the Brown-Goodwin Lifetime History of Aggression (LHA), and high lethality by a score of 4 or more on the Lethality Rating Scale (LRS). Sixteen High Lethality attempters were compared to 35 Low Lethality attempters, with no significant differences noted in gender, co-morbidity, childhood abuse, BIS or LHA scores. Degree of medical lethality (LRS) was negatively related to gray matter volumes across multiple fronto-temporal-limbic regions. Effects of impulsivity and aggression on gray matter volumes discriminated High from Low Lethality attempters and differed markedly within lethality groups. Lethality of suicide attempts in BPD may be related to the mediation of these personality traits by specific neural networks. PMID:24656768

  13. The role of sub-lethal weapons in human rights abuse.

    PubMed

    Wright, S

    2001-01-01

    This article is based on two recent reports contracted by the European Parliament (EP), which assessed sub-lethal weapons as flexible tools of political control. It analyses the role and function of existing weapons systems in human rights abuses using examples from Indonesia, Israel, Kenya, Northern Ireland and Turkey. These weapons are designed to 'appear' rather than 'be' safe and, since they augment rather than replace lethal technologies, their use can distort conflicts and actually bridge the firewall between use of less-lethal and lethal technologies. PMID:11578040

  14. Arabidopsis mutants with increased sensitivity to aluminum.

    PubMed Central

    Larsen, P B; Tai, C Y; Kochian, L V; Howell, S H

    1996-01-01

    Al-sensitive (als) mutants of Arabidopsis were isolated and characterized with the aim of defining mechanisms of Al toxicity and resistance. Most als mutants selected on the basis of root growth sensitivity to Al were recessive, and together the mutants constituted eight complementation groups. Also, in most als mutants, Al sensitivity appeared to be specific for Al relative to La (another trivalent cation), except als2, which was more sensitive to La than wild type. The tendency of roots on mutant seedlings to accumulate Al was examined by staining with morin and hematoxylin, dyes used to indicate the presence of Al. A significant increase in morin staining was observed in als5, consistent with its increased sensitivity to Al. Unexpectedly, als7 and als4 showed less morin staining, suggesting that the roots on these mutants accumulate less Al than wild type seedlings after exposure to Al-containing solutions. Roots of wild-type seedlings produce callose in response to AlCl3 concentrations that inhibit root growth. Only als5 accumulated more callose than wild type in response to low levels (25 mu M) of AICI3 However, als4 and als7 did not accumulate callose at this AlCl3 concentration even though root growth was significantly inhibited. The lack of callose accumulation in als4 and als7 suggests that there is not an obligatory relationship between callose deposition and Al-induced inhibition of root growth. PMID:8819866

  15. Quantitative Analysis of Triple Mutant Genetic Interactions

    PubMed Central

    Braberg, Hannes; Alexander, Richard; Shales, Michael; Xu, Jiewei; Franks-Skiba, Kathleen E.; Wu, Qiuqin; Haber, James E.; Krogan, Nevan J.

    2014-01-01

    The quantitative analysis of genetic interactions between pairs of gene mutations has proven effective for characterizing cellular functions but can miss important interactions for functionally redundant genes. To address this limitation, we have developed an approach termed Triple Mutant Analysis (TMA). The procedure relies on a query strain that contains two deletions in a pair of redundant or otherwise related genes, that is crossed against a panel of candidate deletion strains to isolate triple mutants and measure their growth. A central feature of TMA is to interrogate mutants that are synthetically sick when two other genes are deleted but interact minimally with either single deletion. This approach has been valuable for discovering genes that restore critical functions when the principle actors are deleted. TMA has also uncovered double mutant combinations that produce severe defects because a third protein becomes deregulated and acts in a deleterious fashion, and it has revealed functional differences between proteins presumed to act together. The protocol is optimized for Singer ROTOR pinning robots, takes 3 weeks to complete, and measures interactions for up to 30 double mutants against a library of 1536 single mutants. PMID:25010907

  16. Increased Phagocytosis of Mycobacterium marinum Mutants Defective in Lipooligosaccharide Production

    PubMed Central

    Alibaud, Laeticia; Pawelczyk, Jakub; Gannoun-Zaki, Laila; Singh, Vipul K.; Rombouts, Yoann; Drancourt, Michel; Dziadek, Jaroslaw; Guérardel, Yann; Kremer, Laurent

    2014-01-01

    Mycobacterium marinum is a waterborne pathogen responsible for tuberculosis-like infections in ectotherms and is an occasional opportunistic human pathogen. In the environment, M. marinum also interacts with amoebae, which may serve as a natural reservoir for this microorganism. However, the description of mycobacterial determinants in the early interaction with macrophages or amoebae remains elusive. Lipooligosaccharides (LOSs) are cell surface-exposed glycolipids capable of modulating the host immune system, suggesting that they may be involved in the early interactions of M. marinum with macrophages. Herein, we addressed whether LOS composition affects the uptake of M. marinum by professional phagocytes. Mutants with various truncated LOS variants were generated, leading to the identification of several previously uncharacterized biosynthetic genes (wbbL2, MMAR_2321, and MMAR_2331). Biochemical and structural approaches allowed resolving the structures of LOS precursors accumulating in this set of mutants. These strains with structurally defined LOS profiles were then used to infect both macrophages and Acanthamoebae. An inverse correlation between LOS completeness and uptake of mycobacteria by phagocytes was found, allowing the proposal of three mutant classes: class I (papA4), devoid of LOS and highly efficiently phagocytosed; class II, accumulating only early LOS intermediates (wbbL2 and MMAR_2331) and efficiently phagocytosed but less than class I mutants; class III, lacking LOS-IV (losA, MMAR_2319, and MMAR_2321) and phagocytosed similarly to the control strain. These results indicate that phagocytosis is conditioned by the LOS pattern and that the LOS pathway used by M. marinum in macrophages is conserved during infection of amoebae. PMID:24235141

  17. Wheat ABA-insensitive mutants result in reduced grain dormancy.

    PubMed

    Schramm, Elizabeth C; Nelson, Sven K; Steber, Camille M

    2012-03-31

    This paper describes the isolation of wheat mutants in the hard red spring Scarlet resulting in reduced sensitivity to the plant hormone abscisic acid (ABA) during seed germination. ABA induces seed dormancy during embryo maturation and inhibits the germination of mature seeds. Wheat sensitivity to ABA gradually decreases with dry after-ripening. Scarlet grain normally fails to germinate when fully dormant, shows ABA sensitive germination when partially after-ripened, and becomes ABA insensitive when after-ripened for 8-12 months. Scarlet ABA-insensitive (ScABI) mutants were isolated based on the ability to germinate on 5 µM ABA after only 3 weeks of after-ripening, a condition under which Scarlet would fail to germinate. Six independent seed-specific mutants were recovered. ScABI 1, ScABI2, ScABI3 and ScABI4 are able to germinate more efficiently than Scarlet at up to 25 µM ABA. The two strongest ABA insensitive lines, ScABI3 and ScABI4, both proved to be partly dominant suggesting that they result from gain-of-function mutations. The ScABI1, ScABI2, ScABI3, ScABI4, and ScABI5 mutants after-ripen more rapidly than Scarlet. Thus, ABA insensi-tivity is associated with decreased grain dormancy in Scarlet wheat. This suggests that ABA sensitivity is an important factor controlling grain dormancy in wheat, a trait that impacts seedling emergence and pre-harvest sprouting resistance. PMID:25431501

  18. Morphological analysis of cell growth mutants in Physcomitrella.

    PubMed

    Bibeau, Jeffrey P; Vidali, Luis

    2014-01-01

    This protocol describes a quantitative analysis of the morphology of small plants from the moss Physcomitrella patens. The protocol can be used for the analysis of growth phenotypes produced by transient RNA interference or for the analysis of stable mutant plants. Information is presented to guide the investigator in the choice of vectors and basic conditions to perform transient RNA interference in moss. Detailed directions and examples for fluorescence image acquisition of small regenerating moss plants are provided. Instructions for the use of an ImageJ-based macro for quantitative morphological analysis of these plants are also provided. PMID:24132431

  19. Procalcitonin as a predictive biomarker for total body irradiation induced bacterial load and lethality in mice

    PubMed Central

    Biju, Prabath G.; Garg, Sarita; Wang, Wenze; Choudhry, Mashkoor A.; Kovacs, Elizabeth J.; Fink, Louis M.; Hauer-Jensen, Martin

    2012-01-01

    Sepsis is the leading cause of mortality in intensive care units. Early detection and intervention are critical to prevent death. The acute radiation syndrome is characterized by damage of the gastrointestinal and hematopoietic systems. Translocation of intestinal microflora combined with immune system compromise may lead to septicemia and death. This work examined the utility of procalcitonin, a clinical sepsis biomarker, in a mouse model of radiation toxicity. C57/BL6 mice were exposed to total body irradiation (TBI). Intestinal mucosal permeability was measured in vivo, and liver bacterial load and plasma levels of procalcitonin (PCT), lipopolysaccharide (LPS), and lipopolysaccharide binding protein (LBP) were measured at baseline and 3.5, 7, and 10 days after TBI. The value of early PCT in predicting subsequent lethality was determined by receiver operator characteristics (ROC) analysis. Four days after TBI a dose-dependent increase in permeability of the intestinal mucosa was observed, while bacterial translocation was present from day 7 onward. There was a high positive correlation between bacterial translocation and all sepsis biomarkers, with PCT exhibiting the strongest correlation. Moreover, plasma PCT levels were elevated already from day 3.5 onwards, whereas, LPS was elevated from day 7 and LBP only 10 days after TBI. ROC analysis revealed that PCT levels measured 3.5 days after TBI predicted lethality at 10 days. These data demonstrate the value of PCT as an early biomarker in radiation-induced bacteremia for mouse studies and suggest that clinical results from other septic conditions may apply to post-radiation septicemia in humans. PMID:22576002

  20. EGG-LAYING DEFECTIVE MUTANTS OF THE NEMATODE CAENORHABDITIS ELEGANS

    Microsoft Academic Search

    CAROL TRENT; NANCY TSUNG; H. ROBERT HORVITZ

    1983-01-01

    We have isolated 145 fertile mutants of C. elegons that are defective in egg laying and have characterized 59 of them genetically, behaviorally and phar- macologically. These 59 mutants define 40 new genes called egl, for egg-laying abnormal. Most of the other mutants are defective in previously identified genes. The egl mutants differ with respect to the severity of their

  1. Altered Fermentative Metabolism in Chlamydomonas reinhardtii Mutants Lacking Pyruvate Formate Lyase and Both Pyruvate Formate Lyase and Alcohol Dehydrogenase

    SciTech Connect

    Catalanotti, C.; Dubini, A.; Subramanian, V.; Yang, W. Q.; Magneschi, L.; Mus, F.; Seibert, M.; Posewitz, M. C.; Grossman, A. R.

    2012-02-01

    Chlamydomonas reinhardtii, a unicellular green alga, often experiences hypoxic/anoxic soil conditions that activate fermentation metabolism. We isolated three Chlamydomonas mutants disrupted for the pyruvate formate lyase (PFL1) gene; the encoded PFL1 protein catalyzes a major fermentative pathway in wild-type Chlamydomonas cells. When the pfl1 mutants were subjected to dark fermentative conditions, they displayed an increased flux of pyruvate to lactate, elevated pyruvate decarboxylation, ethanol accumulation, diminished pyruvate oxidation by pyruvate ferredoxin oxidoreductase, and lowered H2 production. The pfl1-1 mutant also accumulated high intracellular levels of lactate, succinate, alanine, malate, and fumarate. To further probe the system, we generated a double mutant (pfl1-1 adh1) that is unable to synthesize both formate and ethanol. This strain, like the pfl1 mutants, secreted lactate, but it also exhibited a significant increase in the levels of extracellular glycerol, acetate, and intracellular reduced sugars and a decrease in dark, fermentative H2 production. Whereas wild-type Chlamydomonas fermentation primarily produces formate and ethanol, the double mutant reroutes glycolytic carbon to lactate and glycerol. Although the metabolic adjustments observed in the mutants facilitate NADH reoxidation and sustained glycolysis under dark, anoxic conditions, the observed changes could not have been predicted given our current knowledge of the regulation of fermentation metabolism.

  2. Poxvirus deletion mutants: virulence and immunogenicity.

    PubMed

    Edwards, K M; Andrews, T C; Van Savage, J; Palmer, P S; Moyer, R W

    1988-05-01

    Post-vaccinial encephalitis and disseminated vaccinia are major concerns with the use of vaccinia virus recombinants as immunization vectors in man. To identify and characterize possible attenuated poxvirus vectors, rabbitpox virus (RPV) (closely related to vaccinia) and four deletion mutants of RPV were studied for organ tropism, neurovirulence, and protection from wild-type challenge in BALB/c mice. Intraperitoneal (IP) inoculation with 10(7) PFU wild-type (wt) RPV or with two mutants 8 sm and 28 (containing approximately 12 kilobase deletions) showed titers of greater than 10(3) PFU/g tissue in multiple organs. In contrast, IP inoculation of 10(7) PFU of mutants 31 or 23 (containing approximately 30 kilobase deletions) showed markedly reduced growth in all organs. Neurovirulence of wt and mutant RPV was determined by intracerebral (IC) inoculation of mice. Wt and mutants 8 sm, and 28 RPV had LD50 less than 10(2) PFU; in contrast, 31 and 23 had LD50 greater than 10(5) PFU. Finally, 10(6) PFU of mutants 31 or 23, were administered to mice by scarification, the normal route of vaccinia immunization. Both 31 and 23 grew locally in the skin and protected mice challenged IC at 21 days with 100 LD50 of wt RPV, while all unimmunized controls died. We conclude that deletion mutants 31 and 23 demonstrate markedly reduced invasiveness and neurovirulence while retaining immunogenicity. Similar deletion mutations in vaccinia may create avirulent, but effective vaccine vectors for man. PMID:2853813

  3. Recovery of Dominant, Autosomal Flightless Mutants of Drosophila Melanogaster and Identification of a New Gene Required for Normal Muscle Structure and Function

    PubMed Central

    Cripps, R. M.; Ball, E.; Stark, M.; Lawn, A.; Sparrow, J. C.

    1994-01-01

    To identify further mutations affecting muscle function and development in Drosophila melanogaster we recovered 22 autosomal dominant flightless mutations. From these we have isolated eight viable and lethal alleles of the muscle myosin heavy chain gene, and seven viable alleles of the indirect flight muscle (IFM)-specific Act88F actin gene. The Mhc mutations display a variety of phenotypic effects, ranging from reductions in myosin heavy chain content in the indirect flight muscles only, to reductions in the levels of this protein in other muscles. The Act88F mutations range from those which produce no stable actin and have severely abnormal myofibrillar structure, to those which accumulate apparently normal levels of actin in the flight muscles but which still have abnormal myofibrils and fly very poorly. We also recovered two recessive flightless mutants on the third chromosome. The remaining five dominant flightless mutations are all lethal alleles of a gene named lethal(3)Laker. The Laker alleles have been characterized and the gene located in polytene bands 62A10,B1-62B2,4. Laker is a previously unidentified locus which is haplo-insufficient for flight. In addition, adult wild-type heterozygotes and the lethal larval trans-heterozygotes show abnormalities of muscle structure indicating that the Laker gene product is an important component of muscle. PMID:8056306

  4. Exploiting the triple response of Arabidopsis to identify ethylene-related mutants.

    PubMed Central

    Guzmán, P; Ecker, J R

    1990-01-01

    Alterations in the response of dark-grown seedlings to ethylene (the "triple response") were used to isolate a collection of ethylene-related mutants in Arabidopsis thaliana. Mutants displaying a constitutive response (eto1) were found to produce at least 40 times more ethylene than the wild type. The morphological defects in etiolated eto1-1 seedlings reverted to wild type under conditions in which ethylene biosynthesis or ethylene action were inhibited. Mutants that failed to display the apical hook in the absence of ethylene (his1) exhibited reduced ethylene production. In the presence of exogenous ethylene, hypocotyl and root of etiolated his1-1 seedlings were inhibited in elongation but no apical hook was observed. Mutants that were insensitive to ethylene (ein1 and ein2) produced increased amounts of ethylene, displayed hormone insensitivity in both hypocotyl and root responses, and showed an apical hook. Each of the "triple response" mutants has an effect on the shape of the seedling and on the production of the hormone. These mutants should prove to be useful tools for dissecting the mode of ethylene action in plants. PMID:2152173

  5. Suppression of mutants aberrant in light intensity responses of complementary chromatic adaptation.

    PubMed Central

    Casey, E S; Kehoe, D M; Grossman, A R

    1997-01-01

    Complementary chromatic adaptation is a process in which cyanobacteria alter the pigment protein (phycocyanin and phycoerythrin) composition of their light-harvesting complexes, the phycobilisomes, to help optimize the absorbance of prevalent wavelengths of light in the environment. Several classes of mutants that display aberrant complementary chromatic adaptation have been isolated. One of the mutant classes, designated "blue" or FdB, accumulates high levels of the blue chromoprotein phycocyanin in low-intensity green light, a condition that normally suppresses phycocyanin synthesis. We demonstrate here that the synthesis of the phycocyanin protein and mRNA in the FdB mutants can be suppressed by increasing the intensity of green light. Hence, these mutants have a decreased sensitivity to green light with respect to suppression of phycocyanin synthesis. Although we were unable to complement the blue mutants, we did isolate genes that could suppress the mutant phenotype. These genes, which have been identified previously, encode a histidine kinase sensor and response regulator protein that play key roles in controlling complementary chromatic adaptation. These findings are discussed with respect to the mechanism by which light quality and quantity control the biosynthesis of the phycobilisome. PMID:9226271

  6. Isolation and characterization of Arabidopsis mutants defective in the induction of ethylene biosynthesis by cytokinin

    NASA Technical Reports Server (NTRS)

    Vogel, J. P.; Schuerman, P.; Woeste, K.; Brandstatter, I.; Kieber, J. J.; Evans, M. L. (Principal Investigator)

    1998-01-01

    Cytokinins elevate ethylene biosynthesis in etiolated Arabidopsis seedlings via a post-transcriptional modification of one isoform of the key biosynthetic enzyme ACC synthase. In order to begin to dissect the signaling events leading from cytokinin perception to this modification, we have isolated a series of mutants that lack the ethylene-mediated triple response in the presence of cytokinin due to their failure to increase ethylene biosynthesis. Analysis of genetic complementation and mapping revealed that these Cin mutants (cytokinin-insensitive) represent four distinct complementation groups, one of which, cin4, is allelic to the constitutive photomorphogenic mutant fus9/cop10. The Cin mutants have subtle effects on the morphology of adult plants. We further characterized the Cin mutants by analyzing ethylene biosynthesis in response to various other inducers and in adult tissues, as well as by assaying additional cytokinin responses. The cin3 mutant did not disrupt ethylene biosynthesis under any other conditions, nor did it disrupt any other cytokinin responses. Only cin2 disrupted ethylene biosynthesis in multiple circumstances. cin1 and cin2 made less anthocyanin in response to cytokinin. cin1 also displayed reduced shoot initiation in tissue culture in response to cytokinin, suggesting that it affects a cytokinin signaling element.

  7. Heterofermentative Carbohydrate Metabolism of Lactose-Impaired Mutants of Streptococcus lactis

    PubMed Central

    Demko, G. M.; Blanton, S. J. B.; Benoit, R. E.

    1972-01-01

    Two mutants of Streptococcus lactis ATCC 11454 have been isolated which possess an impaired lactose-fermenting capacity; galactose utilization is also affected, but to a lesser extent. Although the Embden-Meyerhof-Parnas pathway is the major, if not the sole, pathway of carbohydrate metabolism in the three strains, the fermentation end products of the mutants are dramatically different from the typical homolactic pattern of the wild type. Under conditions of low oxygen tension and growth-limiting lactose concentrations, mutant strain T-1 produces largely formic acid, acetic acid (2:1), and ethanol rather than lactic acid. Aerated cultures produce acetic acid, CO2 (1:1), acetyl-methylcarbinol, and diacetyl. When the mutants use galactose as an energy source, lactic acid is the major end product, but significant heterofermentative activity is observed. The aberrations responsible for the mutant phenotypes reside in the proteins which catalyze the transport and hydrolysis of galactosides. It is hypothesized that the impaired transport system of the mutants reduces the intracellular pool of glycolytic intermediates below that of the wild type. Since fructose-1, 6-diphosphate is an activator of lactic dehydrogenase in S. lactis, lactic acid production is reduced, and pathways leading to the formation of other products are expressed. PMID:4629656

  8. FOLIC ACID METABOLISM IN ANTIFOLIC-RESISTANT MUTANTS OF STREPTOCOCCUS FAECALIS

    PubMed Central

    Johnson, Alva H.; Hutchison, Dorris J.

    1964-01-01

    Johnson, Alva H. (Sloan-Kettering Institute for Cancer Research, Rye, N.Y.), and Dorris J. Hutchison. Folic acid metabolism in antifolic-resistant mutants of Streptococcus faecalis. J. Bacteriol. 87:786–791. 1964.—Streptococcus faecalis ATCC 8043 and three of its mutants resistant to amethopterin were compared for their quantitative requirements for serine, purines, and thymine; for their quantitative requirements of folic acid (FA) for the synthesis de novo of serine, purines, and thymine; for the susceptibility to amethopterin of each pathway; and for the relative capacity of resting cells of each culture to synthesize N5-formyltetrahydrofolate (5-CHOFAH4) from FA and serine or FA and formate. The mutants were found to be both qualitatively and quantitatively different from one another and from the wild strain. The growth conditions, specifically the composition of the medium in which each mutant strain was selected, had a marked effect on the metabolic capacities of the mutants. The ability to synthesize serine, purines, and thymine, as observed from the FA requirements, directly reflected the level of resistance of each pathway to amethopterin. The resistant mutants were more efficient than the wild strain in the formation of 5-CHOFAH4 from FA and formate and, furthermore, this formate activation paralleled their capacities in the synthesis de novo of serine. Alterations in purine and thymine biosyntheses were also observed. PMID:14137614

  9. Batrachochytrium dendrobatidis infection and lethal chytridiomycosis in caecilian amphibians (Gymnophiona).

    PubMed

    Gower, David J; Doherty-Bone, Thomas; Loader, Simon P; Wilkinson, Mark; Kouete, Marcel T; Tapley, Benjamin; Orton, Frances; Daniel, Olivia Z; Wynne, Felicity; Flach, Edmund; Müller, Hendrik; Menegon, Michele; Stephen, Ian; Browne, Robert K; Fisher, Mathew C; Cunningham, Andrew A; Garner, Trenton W J

    2013-06-01

    Batrachochytrium dendrobatidis (Bd) is commonly termed the 'amphibian chytrid fungus' but thus far has been documented to be a pathogen of only batrachian amphibians (anurans and caudatans). It is not proven to infect the limbless, generally poorly known, and mostly soil-dwelling caecilians (Gymnophiona). We conducted the largest qPCR survey of Bd in caecilians to date, for more than 200 field-swabbed specimens from five countries in Africa and South America, representing nearly 20 species, 12 genera, and 8 families. Positive results were recovered for 58 specimens from Tanzania and Cameroon (4 families, 6 genera, 6+ species). Quantities of Bd were not exceptionally high, with genomic equivalent (GE) values of 0.052-17.339. In addition, we report the first evidence of lethal chytridiomycosis in caecilians. Mortality in captive (wild-caught, commercial pet trade) Geotrypetes seraphini was associated with GE scores similar to those we detected for field-swabbed, wild animals. PMID:23677560

  10. Clinical Effects and Lethal and Forensic Aspects of Propofol*

    PubMed Central

    Levy, Richard J.

    2010-01-01

    Propofol is a potent intravenous anesthetic agent that rapidly induces sedation and unconsciousness. The potential for propofol dependency, recreational use and abuse has only recently been recognized and several cases of accidental overdose and suicide have emerged. In addition, the first documented case of murder using propofol was reported a few months ago and a high profile case of suspected homicide with propofol is currently under investigation. A number of analytical methods have been employed to detect and quantify propofol concentrations in biological specimens. The reported propofol related deaths and post-mortem blood and tissue levels are reviewed. Importantly, limitations of propofol detection are discussed and future considerations are presented. Because propofol has the potential for diversion with lethal consequences, the forensic scientist must have a basic understanding of its clinical indications and uses, pharmacologic properties, and detection methods. In addition, medical institutions should develop systems to prevent and detect diversion of this potential drug of abuse. PMID:20950316

  11. DDE in birds: Lethal residues and loss rates

    USGS Publications Warehouse

    Stickel, W.H.; Stickel, L.F.; Dyrland, R.A.; Hughes, D.L.

    1984-01-01

    Lethal brain residues of DDE were determined experimentally in four species of wild birds (male common grackels (Quiscalus quiscula ), immature female red-winged blackbirds (Agelaius phoeniceus ), adult male brown-headed cowbirds (Molathrus ater ), and immature female starlings (Sturnus vulgaris ) given dietary dosage of 1,500 ppm DDE until one-half had died, then sacrificing the survivors, chemically analyzing the tissues, and comparing results in dead birds and survivors. In all species, residues of 300 to 400 ppm of DDE in the brain were considered to show increasing likelihood of death from DDE, confirming results of an earlier study with a single species. Body residues (ppm wet weight) were not diagnostic, overlapping grossly in dead birds and survivors, but averaging higher in survivors.

  12. Aroclor 1254 residues in birds: Lethal levels and loss rates

    USGS Publications Warehouse

    Stickel, W.H.; Stickel, L.F.; Dyrland, R.A.; Hughes, D.L.

    1984-01-01

    Lethal residues of polychlorinated biphenyls (PCBs) were determined experimentally in four species of wild birds (male common grackles (Quiscalus quiscula ), immature female red-winged blackbirds (Agelaius phoeniceus ), adult male brown-headed cowbirds (Molothrus ater ) and immature female starlings (Sturnus vulgaris)) given dietary dosage of 1,500 ppm of Aroclor 1254) until one-half had died, sacrificing the survivors, chemically analyzing the tissues, and comparing results in dead birds and survivors. For all species, residues of 310 ppm or higher in the brain showed increasing likelihood of death from PCB poisoning. Residues in dead birds did not differ among species except for starlings (Sturnus vulgaris ), which averaged slightly lower than the others. However, the species differed in the length of time to 50% mortality and in the levels of PCBs in brains at sacrifice.

  13. Developmental basis of severe neural tube defects in the loop-tail (Lp) mutant mouse: use of microsatellite DNA markers to identify embryonic genotype.

    PubMed

    Copp, A J; Checiu, I; Henson, J N

    1994-09-01

    Mouse embryos homozygous for the mutation loop-tail (Lp) develop lethal defects in which the neural tube remains open from the hindbrain to the caudal extremity, a condition that closely resembles the human malformation craniorachischisis. Heterozygotes develop tail defects and occasional spina bifida, but are generally viable. In order to study the early development of these defects, it is necessary to determine the genotype of embryos at stages prior to the first appearance of the morphological abnormalities. We used a microsatellite DNA sequence, Crp, that is closely linked to the Lp locus and which segregates polymorphic variants in matings between Lp/+ mice, thus permitting identification of embryos of Lp/Lp, Lp/+ and +/+ genotypes. We found that the severe phenotype craniorachischisis is present at 9.5 and 10.5 days of gestation only in Lp/Lp embryos in utero, whereas Lp/+ and +/+ littermates show neural tube closure throughout most of the body axis. The open neural tube phenotype also develops in Lp/Lp embryos growing in whole embryo culture. A small proportion of Lp/+ embryos were found to develop this phenotype in vitro, but only when culture conditions were suboptimal. Analysis of 8.5-day embryos revealed that the initial defect in Lp/Lp embryos is failure to initiate neural tube closure at the cervical/hindbrain boundary when the embryo has 6-7 somites. Thereafter, the neural tube remains open throughout the body axis, with the exception of the midbrain and forebrain where neural tube closure is initiated independently. Closure at the midbrain/forebrain boundary does not appear to be defective in Lp/Lp embryos. Heterozygous Lp/+ embryos initiate neural tube closure at the cervical/hindbrain boundary with a slight delay compared with +/+ littermates. Moreover, at 10.5 days of gestation, Lp/+ embryos undergo delayed closure of the posterior neuropore. Thus, Lp/+ embryos are defective in several aspects of the neurulation process. The pattern of delayed neuropore closure in Lp/+ embryos resembles that caused by the ct and Sp mutations and is likely to be responsible for the development of tail defects (i.e., looped tails) and spina bifida in Lp/+ mice. The use of microsatellite markers to determine the genotype of mutant embryos has general application: microsatellites are widespread throughout the mouse genome, so that informative sequences are likely to be available with close linkage to the majority of mutant genes. Moreover, polymorphisms can be detected using the polymerase chain reaction, making it possible to determine the genotype of very early embryos when only small amounts of material are available. PMID:8088438

  14. Agravitropic mutants of the moss Ceratodon purpureus do not complement mutants having a reversed gravitropic response

    Microsoft Academic Search

    DAVID J. COVE; RALPH S. QUATRANO

    2006-01-01

    New mutants of the moss Ceratodon purpureus have been isolated, which showed abnormal gravitropic responses. The apical cells of protonemal filaments of wild-type strains respond to gravity by growing upwards and are well aligned to the gravity vector. This response only occurs in darkness. Mutants show a range of phenotypes. Some are insensitive to gravity, showing symmetrical growth, while others

  15. Novel peroxisome clustering mutants and peroxisome biogenesis mutants of Saccharomyces cerevisiae

    PubMed Central

    1993-01-01

    The goal of this research is to identify and characterize the protein machinery that functions in the intracellular translocation and assembly of peroxisomal proteins in Saccharomyces cerevisiae. Several genes encoding proteins that are essential for this process have been identified previously by Kunau and collaborators, but the mutant collection was incomplete. We have devised a positive selection procedure that identifies new mutants lacking peroxisomes or peroxisomal function. Immunofluorescence procedures for yeast were simplified so that these mutants could be rapidly and efficiently screened for those in which peroxisome biogenesis is impaired. With these tools, we have identified four complementation groups of peroxisome biogenesis mutants, and one group that appears to express reduced amounts of peroxisomal proteins. Two of our mutants lack recognizable peroxisomes, although they might contain peroxisomal membrane ghosts like those found in Zellweger syndrome. Two are selectively defective in packaging peroxisomal proteins and moreover show striking intracellular clustering of the peroxisomes. The distribution of mutants among complementation groups implies that the collection of peroxisome biogenesis mutants is still incomplete. With the procedures described, it should prove straightforward to isolate mutants from additional complementation groups. PMID:7902359

  16. Lethal Mutagenesis of Poliovirus Mediated by a Mutagenic Pyrimidine Analogue?

    PubMed Central

    Graci, Jason D.; Harki, Daniel A.; Korneeva, Victoria S.; Edathil, Jocelyn P.; Too, Kathleen; Franco, David; Smidansky, Eric D.; Paul, Aniko V.; Peterson, Blake R.; Brown, Daniel M.; Loakes, David; Cameron, Craig E.

    2007-01-01

    Lethal mutagenesis is the mechanism of action of ribavirin against poliovirus (PV) and numerous other RNA viruses. However, there is still considerable debate regarding the mechanism of action of ribavirin against a variety of RNA viruses. Here we show by using T7 RNA polymerase-mediated production of PV genomic RNA, PV polymerase-catalyzed primer extension, and cell-free PV synthesis that a pyrimidine ribonucleoside triphosphate analogue (rPTP) with ambiguous base-pairing capacity is an efficient mutagen of the PV genome. The in vitro incorporation properties of rPTP are superior to ribavirin triphosphate. We observed a log-linear relationship between virus titer reduction and the number of rPMP molecules incorporated. A PV genome encoding a high-fidelity polymerase was more sensitive to rPMP incorporation, consistent with diminished mutational robustness of high-fidelity PV. The nucleoside (rP) did not exhibit antiviral activity in cell culture, owing to the inability of rP to be converted to rPMP by cellular nucleotide kinases. rP was also a poor substrate for herpes simplex virus thymidine kinase. The block to nucleoside phosphorylation could be bypassed by treatment with the P nucleobase, which exhibited both antiviral activity and mutagenesis, presumably a reflection of rP nucleotide formation by a nucleotide salvage pathway. These studies provide additional support for lethal mutagenesis as an antiviral strategy, suggest that rPMP prodrugs may be highly efficacious antiviral agents, and provide a new tool to determine the sensitivity of RNA virus genomes to mutagenesis as well as interrogation of the impact of mutational load on the population dynamics of these viruses. PMID:17686844

  17. Tumor expression of adiponectin receptor 2 and lethal prostate cancer.

    PubMed

    Rider, Jennifer R; Fiorentino, Michelangelo; Kelly, Rachel; Gerke, Travis; Jordahl, Kristina; Sinnott, Jennifer A; Giovannucci, Edward L; Loda, Massimo; Mucci, Lorelei A; Finn, Stephen

    2015-06-01

    To investigate the role of adiponectin receptor 2 (AdipoR2) in aggressive prostate cancer we used immunohistochemistry to characterize AdipoR2 protein expression in tumor tissue for 866 men with prostate cancer from the Physicians' Health Study and the Health Professionals Follow-up Study. AdipoR2 tumor expression was not associated with measures of obesity, pathological tumor stage or prostate-specific antigen (PSA) at diagnosis. However, AdipoR2 expression was positively associated with proliferation as measured by Ki-67 expression quartiles (P-trend < 0.0001), with expression of fatty acid synthase (P-trend = 0.001), and with two measures of angiogenesis (P-trend < 0.1). An inverse association was observed with apoptosis as assessed by the TUNEL assay (P-trend = 0.006). Using Cox proportional hazards regression and controlling for age at diagnosis, Gleason score, year of diagnosis category, cohort and baseline BMI, we identified a statistically significant trend for the association between quartile of AdipoR2 expression and lethal prostate cancer (P-trend = 0.02). The hazard ratio for lethal prostate cancer for the two highest quartiles, as compared to the two lowest quartiles, of AdipoR2 expression was 1.9 (95% confidence interval [CI]: 1.2-3.0). Results were similar when additionally controlling for categories of PSA at diagnosis and Ki-67 expression quartiles. These results strengthen the evidence for the role of AdipoR2 in prostate cancer progression. PMID:25863129

  18. Lysosome and Phagosome Stability in Lethal Cell Injury

    PubMed Central

    Hawkins, Hal K.; Ericsson, Jan L. E.; Biberfeld, Peter; Trump, Benjamin F.

    1972-01-01

    In two types of cell injury in a tissue culture system, the possibility was tested that lysosome rupture may be a lethal cellular reaction to injury, and thus an important general cause of irreversibility of damage in injured tissue. Prior labeling of secondary lysosomes with the fluorochrome acridine orange, or with ferritin, was used to trace changes in lysosomes after applying an injury. The metabolic inhibitors iodoacetate and cyanide were used together to block the cell's energy supply, or attachment of antiserum and subsequent complement attack were used to damage the surface membrane, producing rapid loss of cell volume control. Living cells were studied by time-lapse phase-contrast cinemicrography and fluorescence microscopy, and samples were fixed at intervals for electron microscopy. The cytolytic action of complement was lethal to sensitized cells within 2 hours, but results showed that lysosomes did not rupture for approximately 4 hours and in fact did not release the fluorescent dye until after reaching the postmortem necrotic phase of injury. Cells treated with metabolic inhibitors also showed irreversible alterations, while lysosomes remained intact and retained the ferritin marker. The fluorochrome marker, acridine orange, escaped from lysosomes early after metabolic injury, but the significance of this observation is not clear. The results are interpreted as evidence against the concept that lysosome rupture threatens the survival of injured cells. The original suicide bag mechanism of cell damage thus is apparently not operative in the systems studied. Lysosomes appear to be relatively stable organelles which, following injury of the types studied, burst only after cell death, acting then as scavengers which help to clear cellular debris. ImagesFigs 5-7Fig 18Fig 19Fig 20Figs 21-23Fig 8Fig 9Fig 10Fig 11Figs 24-27Fig 12Figs 13 and 14Fig 1Fig 2Fig 3Fig 4Fig 15Fig 16Fig 17 PMID:4340333

  19. The SUMO isopeptidase Ulp2p is required to prevent recombination-induced chromosome segregation lethality following DNA replication stress.

    PubMed

    Lee, Ming-Ta; Bakir, Abla A; Nguyen, Kristen N; Bachant, Jeff

    2011-03-01

    SUMO conjugation is a key regulator of the cellular response to DNA replication stress, acting in part to control recombination at stalled DNA replication forks. Here we examine recombination-related phenotypes in yeast mutants defective for the SUMO de-conjugating/chain-editing enzyme Ulp2p. We find that spontaneous recombination is elevated in ulp2 strains and that recombination DNA repair is essential for ulp2 survival. In contrast to other SUMO pathway mutants, however, the frequency of spontaneous chromosome rearrangements is markedly reduced in ulp2 strains, and some types of rearrangements arising through recombination can apparently not be tolerated. In investigating the basis for this, we find DNA repair foci do not disassemble in ulp2 cells during recovery from the replication fork-blocking drug methyl methanesulfonate (MMS), corresponding with an accumulation of X-shaped recombination intermediates. ulp2 cells satisfy the DNA damage checkpoint during MMS recovery and commit to chromosome segregation with similar kinetics to wild-type cells. However, sister chromatids fail to disjoin, resulting in abortive chromosome segregation and cell lethality. This chromosome segregation defect can be rescued by overproducing the anti-recombinase Srs2p, indicating that recombination plays an underlying causal role in blocking chromatid separation. Overall, our results are consistent with a role for Ulp2p in preventing the formation of DNA lesions that must be repaired through recombination. At the same time, Ulp2p is also required to either suppress or resolve recombination-induced attachments between sister chromatids. These opposing defects may synergize to greatly increase the toxicity of DNA replication stress. PMID:21483811

  20. Synthetic Lethal Analysis Implicates Ste20p, a p21-activated Protein Kinase, in Polarisome ActivationD?

    PubMed Central

    Goehring, April S.; Mitchell, David A.; Tong, Amy Hin Yan; Keniry, Megan E.; Boone, Charles; Sprague, George F.

    2003-01-01

    The p21-activated kinases Ste20p and Cla4p carry out undefined functions that are essential for viability during budding in Saccharomyces cerevisiae. To gain insight into the roles of Ste20p, we have used a synthetic lethal mutant screen to identify additional genes that are required in the absence of Cla4p. Altogether, we identified 65 genes, including genes with roles in cell polarity, mitosis, and cell wall maintenance. Herein, we focus on a set that defines a function carried out by Bni1p and several of its interacting proteins. We found that Bni1p and a group of proteins that complex with Bni1p (Bud6p, Spa2p, and Pea2p) are essential in a cla4? mutant background. Bni1p, Bud6p, Spa2, and Pea2p are members of a group of polarity determining proteins referred to as the polarisome. Loss of polarisome proteins from a cla4? strain causes cells to form elongated buds that have mislocalized septin rings. In contrast, other proteins that interact with or functionally associate with Bni1p and have roles in nuclear migration and cytokinesis, including Num1p and Hof1p, are not essential in the absence of Cla4p. Finally, we have found that Bni1p is phosphorylated in vivo, and a substantial portion of this phosphorylation is dependent on STE20. Together, these results suggest that one function of Ste20p may be to activate the polarisome complex by phosphorylation of Bni1p. PMID:12686605

  1. Dual role for Drosophila lethal of scute in CNS midline precursor formation and dopaminergic neuron and motoneuron cell fate

    PubMed Central

    Stagg, Stephanie B.; Guardiola, Amaris R.; Crews, Stephen T.

    2011-01-01

    Dopaminergic neurons play important behavioral roles in locomotion, reward and aggression. The Drosophila H-cell is a dopaminergic neuron that resides at the midline of the ventral nerve cord. Both the H-cell and the glutamatergic H-cell sib are the asymmetric progeny of the MP3 midline precursor cell. H-cell sib cell fate is dependent on Notch signaling, whereas H-cell fate is Notch independent. Genetic analysis of genes that could potentially regulate H-cell fate revealed that the lethal of scute [l(1)sc], tailup and SoxNeuro transcription factor genes act together to control H-cell gene expression. The l(1)sc bHLH gene is required for all H-cell-specific gene transcription, whereas tailup acts in parallel to l(1)sc and controls genes involved in dopamine metabolism. SoxNeuro functions downstream of l(1)sc and controls expression of a peptide neurotransmitter receptor gene. The role of l(1)sc may be more widespread, as a l(1)sc mutant shows reductions in gene expression in non-midline dopaminergic neurons. In addition, l(1)sc mutant embryos possess defects in the formation of MP4-6 midline precursor and the median neuroblast stem cell, revealing a proneural role for l(1)sc in midline cells. The Notch-dependent progeny of MP4-6 are the mVUM motoneurons, and these cells also require l(1)sc for mVUM-specific gene expression. Thus, l(1)sc plays an important regulatory role in both neurogenesis and specifying dopaminergic neuron and motoneuron identities. PMID:21558367

  2. GAMPMS: Genetic algorithm managed peptide mutant screening.

    PubMed

    Long, Thomas; McDougal, Owen M; Andersen, Tim

    2015-06-30

    The prominence of endogenous peptide ligands targeted to receptors makes peptides with the desired binding activity good molecular scaffolds for drug development. Minor modifications to a peptide's primary sequence can significantly alter its binding properties with a receptor, and screening collections of peptide mutants is a useful technique for probing the receptor-ligand binding domain. Unfortunately, the combinatorial growth of such collections can limit the number of mutations which can be explored using structure-based molecular docking techniques. Genetic algorithm managed peptide mutant screening (GAMPMS) uses a genetic algorithm to conduct a heuristic search of the peptide's mutation space for peptides with optimal binding activity, significantly reducing the computational requirements of the virtual screening. The GAMPMS procedure was implemented and used to explore the binding domain of the nicotinic acetylcholine receptor (nAChR) ?3?2-isoform with a library of 64,000 ?-conotoxin (?-CTx) MII peptide mutants. To assess GAMPMS's performance, it was compared with a virtual screening procedure that used AutoDock to predict the binding affinity of each of the ?-CTx MII peptide mutants with the ?3?2-nAChR. The GAMPMS implementation performed AutoDock simulations for as few as 1140 of the 64,000 ?-CTx MII peptide mutants and could consistently identify a set of 10 peptides with an aggregated binding energy that was at least 98% of the aggregated binding energy of the 10 top peptides from the exhaustive AutoDock screening. © 2015 Wiley Periodicals, Inc. PMID:25975567

  3. Foal with Overo lethal white syndrome born to a registered quarter horse mare

    PubMed Central

    Lightbody, Tamara

    2002-01-01

    A 16-hour-old white foal, born to a registered quarter horse mare, was examined for signs of colic. The foal had Overo lethal white syndrome, which causes ileocolonic agangliosis. This was confirmed by DNA testing. Since there is no treatment for Overo lethal white syndrome, the foal was euthanized. PMID:12240532

  4. Examining the Impact of Psychiatric Diagnosis and Comorbidity on the Medical Lethality of Adolescent "Suicide Attempts"

    ERIC Educational Resources Information Center

    Mc Manama O'Brien, Kimberly H.; Berzin, Stephanie C.

    2012-01-01

    Specific psychiatric diagnoses and comorbidity patterns were examined to determine if they were related to the medical lethality of "suicide attempts" among adolescents presenting to an urban general hospital (N = 375). Bivariate analysis showed that attempters with substance abuse disorders had higher levels of lethality than attempters without…

  5. Experimental studies on effects of sub-lethal dose of pulsed electric field on Hela cells

    Microsoft Academic Search

    Chengxiang Li; Chenguo Yao; Yanshan Qin; Yan Mi; Xiaoyun Liu; Zhengai Xiong

    2010-01-01

    In this paper, we studied the effects of sub-lethal dose of pulsed electric field on cervical cancer cells to achieve an efficient IRE by experiments on Hela cells. MTT and flow cytometry were used to detect the cell viability and cell circle. From the experiment results, it could be concluded that cell proliferation is inhibited by the sub-lethal dose field

  6. PEX11  Deficiency Is Lethal and Impairs Neuronal Migration but Does Not Abrogate Peroxisome Function

    Microsoft Academic Search

    Xiaoling Li; Eveline Baumgart; James C. Morrell; Gerardo Jimenez-Sanchez; David Valle; Stephen J. Gould

    2002-01-01

    Zellweger syndrome is a lethal neurological disorder characterized by severe defects in peroxisomal protein import. The resulting defects in peroxisome metabolism and the accumulation of peroxisomal substrates are thought to cause the other Zellweger syndrome phenotypes, including neuronal migration defects, hypotonia, a developmental delay, and neonatal lethality. These phenotypes are also manifested in mouse models of Zellweger syndrome generated by

  7. Co-lethality studied as an asset against viral drug escape: the HIV protease case

    PubMed Central

    2010-01-01

    Background Co-lethality, or synthetic lethality is the documented genetic situation where two, separately non-lethal mutations, become lethal when combined in one genome. Each mutation is called a "synthetic lethal" (SL) or a co-lethal. Like invariant positions, SL sets (SL linked couples) are choice targets for drug design against fast-escaping RNA viruses: mutational viral escape by loss of affinity to the drug may induce (synthetic) lethality. Results From an amino acid sequence alignment of the HIV protease, we detected the potential SL couples, potential SL sets, and invariant positions. From the 3D structure of the same protein we focused on the ones that were close to each other and accessible on the protein surface, to possibly bind putative drugs. We aligned 24,155 HIV protease amino acid sequences and identified 290 potential SL couples and 25 invariant positions. After applying the distance and accessibility filter, three candidate drug design targets of respectively 7 (under the flap), 4 (in the cantilever) and 5 (in the fulcrum) amino acid positions were found. Conclusions These three replication-critical targets, located outside of the active site, are key to our anti-escape strategy. Indeed, biological evidence shows that 2/3 of those target positions perform essential biological functions. Their mutational variations to escape antiviral medication could be lethal, thus limiting the apparition of drug-resistant strains. Reviewers This article was reviewed by Arcady Mushegian, Shamil Sunyaev and Claus Wilke. PMID:20565756

  8. BIOASSAY PROTOCOL FOR LETHAL AND SUBLETHAL EFFECTS OF FUNGAL PATHOGENS ON CHRYSOPERLA CARNEA

    EPA Science Inventory

    This practice describes procedures for evaluating the lethal and sub-lethal effects of exposure to fungal pathogens on larvae and adults of the predatory insect Chrysoperla carnea (Stephens). his practice was developed and tested with the fungal insect pathogen Beauveria bassiana...

  9. Evaluating the Predictive Validity of Suicidal Intent and Medical Lethality in Youth

    ERIC Educational Resources Information Center

    Sapyta, Jeffrey; Goldston, David B.; Erkanli, Alaattin; Daniel, Stephanie S.; Heilbron, Nicole; Mayfield, Andrew; Treadway, S. Lyn

    2012-01-01

    Objectives: To examine whether suicidal intent and medical lethality of past suicide attempts are predictive of future attempts, the association between intent and lethality, and the consistency of these characteristics across repeated attempts among youth. Method: Suicide attempts in a 15-year prospective study of 180 formerly psychiatrically…

  10. Impairment of dendritic cells and adaptive immunity by anthrax lethal toxin

    Microsoft Academic Search

    Anshu Agrawal; Jai Lingappa; Stephen H. Leppla; Sudhanshu Agrawal; Abdul Jabbar; Conrad Quinn; Bali Pulendran

    2003-01-01

    Anthrax poses a clear and present danger as an agent of biological terrorism. Infection with Bacillus anthracis, the causative agent of anthrax, if untreated can result in rampant bacteraemia, multisystem dysfunction and death. Anthrax lethal toxin (LT) is a critical virulence factor of B. anthracis, which occurs as a complex of protective antigen and lethal factor. Here we demonstrate that

  11. The Danger Assessment: Validation of a Lethality Risk Assessment Instrument for Intimate Partner Femicide

    ERIC Educational Resources Information Center

    Campbell, Jacquelyn C.; Webster, Daniel W.; Glass, Nancy

    2009-01-01

    The Danger Assessment (DA) is an instrument designed to assess the likelihood of lethality or near lethality occurring in a case of intimate partner violence. This article describes the development, psychometric validation, and suggestions for use of the DA. An 11-city study of intimate partner femicide used multivariate analysis to test the…

  12. Effects of Training with Lethal Chemicals on Job Proficiency and Job Confidence.

    ERIC Educational Resources Information Center

    Smith, Paula; And Others

    A study was designed to determine if soldiers trained to use chemical agents are more proficient in performing their jobs in an environment where lethal chemical agents are used and more confident of their ability to survive. A treatment group, composed of 150 soldiers, knew that their training would involve lethal agents in the Chemical…

  13. Genetically modified anthrax lethal toxin safely delivers whole HIV protein antigens into the

    E-print Network

    Lieberman, Judy

    , 2000 (received for review January 24, 2000) Bacillus anthrax lethal toxin can be engineered to deliverGenetically modified anthrax lethal toxin safely delivers whole HIV protein antigens compartment of mammalian cells. The engineered anthrax toxin vaccine appears unlikely to induce an antibody

  14. A fragment of anthrax lethal factor delivers proteins to the cytosol without requiring protective antigen

    E-print Network

    Lieberman, Judy

    A fragment of anthrax lethal factor delivers proteins to the cytosol without requiring protective by Elkan R. Blout, Harvard Medical School, Cambridge, MA, April 2, 2003 (received for review March 10, 2003) Anthrax protective antigen (PA) is a 735-aa polypeptide that facili- tates the exit of anthrax lethal

  15. Cellular and systemic effects of anthrax lethal toxin and edema toxin

    Microsoft Academic Search

    Mahtab Moayeri; Stephen H. Leppla

    2009-01-01

    Anthrax lethal toxin (LT) and edema toxin (ET) are the major virulence factors of anthrax and can replicate the lethality and symptoms associated with the disease. This review provides an overview of our current understanding of anthrax toxin effects in animal models and the cytotoxicity (necrosis and apoptosis) induced by LT in different cells. A brief reexamination of early historic

  16. Anthrax Lethal Toxin-Mediated Killing of Human and Murine Dendritic Cells Impairs

    E-print Network

    Brojatsch, Jürgen

    Anthrax Lethal Toxin-Mediated Killing of Human and Murine Dendritic Cells Impairs the Adaptive anthracis interferes with host defenses by releasing anthrax lethal toxin (LT), which inactivates mitogen that anthrax LT impairs adaptive immunity by specifically targeting DCs. This may represent an immune- evasion

  17. Human synthetic lethal inference as potential anti-cancer target gene detection

    Microsoft Academic Search

    Nuria Conde-Pueyo; Andreea Munteanu; Ricard V Solé; Carlos Rodríguez-Caso

    2009-01-01

    BACKGROUND: Two genes are called synthetic lethal (SL) if mutation of either alone is not lethal, but mutation of both leads to death or a significant decrease in organism's fitness. The detection of SL gene pairs constitutes a promising alternative for anti-cancer therapy. As cancer cells exhibit a large number of mutations, the identification of these mutated genes' SL partners

  18. ORIGINAL ARTICLE Evolution of the Sex-lethal Gene in Insects and Origin

    E-print Network

    Nei, Masatoshi

    ORIGINAL ARTICLE Evolution of the Sex-lethal Gene in Insects and Origin of the Sex-Determination Sex-lethal (Sxl) functions as the switch gene for sex-determination in Drosophila melanogaster protein's sex- determination function have remained largely unknown. In this study, we explore

  19. This Genetic Condition Was Not Inherited

    NSDL National Science Digital Library

    Ingrid Waldron

    This minds-on analysis and discussion activity guides students to think about how mutation and meiotic nondisjunction can result in genetic conditions that are not inherited (most cases of achondroplasia and Down syndrome, respectively). This activity also addresses the reasons for the rarity of inherited lethal dominant alleles.

  20. Conditional lethality of a yeast strain expressing human RHOA in place of RHO1.

    PubMed Central

    Qadota, H; Anraku, Y; Botstein, D; Ohya, Y

    1994-01-01

    The yeast RHO1 GTPase, which has 72% amino acid sequence identity with its human counterpart, RHOA, is essential for growth, although the reason has not been investigated. We report here that yeast strains that rely solely on expression of human RHOA in place of RHO1 are able to grow at 23 degrees C but grow neither at 37 degrees C nor in the presence of 300 mM CaCl2 even at 23 degrees C. Measurements of steady-state protein levels indicate that inability to grow at the restrictive temperature is not due to instability of the protein. Homolog scanning with the two GTPases identified a small, 27-residue region of RHO1 which, when substituted into RHOA, confers full function in yeast. This region corresponds to the alpha 3-helix loop 7 region of RAS; the same region was reported to determine specificity of function between GTPases of the RAB family, Sec4p and Ypt1p. By examining the phenotype of RHOA substitution strains at nonpermissive temperature, we found evidence suggesting that the normal function of RHO1 is to maintain osmotic integrity. Images PMID:7937763

  1. Structure of mutant human oncogene protein determined

    SciTech Connect

    Baum, R.

    1989-01-16

    The protein encoded by a mutant human oncogene differs only slightly in structure from the native protein that initiates normal cell division, a finding that may complicate efforts to develop inhibitors of the mutant protein. Previously, the x-ray structure of the protein encoded by the normal c-Ha-ras gene, a protein believed to signal cells to start or stop dividing through its interaction with guanosine triphosphate (GTP), was reported. The structure of the protein encoded by a transforming c-Ha-ras oncogene, in which a valine codon replaces the normal glycine codon at position 12 in the gene, has now been determined. The differences in the structures of the mutant and normal proteins are located primarily in a loop that interacts with the /beta/-phosphate of a bound guanosine diphosphate (GDP) molecule.

  2. Autolytic defective mutant of Streptococcus faecalis.

    PubMed Central

    Cornett, J B; Redman, B E; Shockman, G D

    1978-01-01

    Properties of a variant of Streptococcus faecalis ATCC 9790 with defective cellular autolysis are described. The mutant strain was selected as a survivor from a mutagenized cell population simultaneously challenged with two antibiotics which inhibit cell wall biosynthesis, penicillin G and cycloserine. Compared to the parental strain, the mutant strain exhibited: (i) a thermosensitive pattern of cellular autolysis; (ii) an autolytic enzyme activity that had only a slightly increased thermolability when tested in solution in the absence of wall substrate; and (iii) an isolated autolysin that had hydrolytic activity on isolated S. faecalis wall substrate indistinguishable from that of the parental strain, but that was inactive when tested on walls of Micrococcus lysodeikticus as a substrate. These data indicate an alteration in the substrate specificity of the autolytic enzyme of the mutant which appears to result from the synthesis of an altered form of autolytic enzyme. PMID:415045

  3. Properties of Bacillus cereus spore coat mutants.

    PubMed Central

    Aronson, A I; Fitz-James, P C

    1975-01-01

    Two classes of spore mutants have been selected in Bacillus cereus T, those producing lysozyme-sensitive spores, and those producing spores dependent upon lysozyme for germination. One mutant from each class was studied in detail and found to have defective packing of the spore coat layers. The major spore coat poplypeptide appeared to be altered on the basis of gel electrophoretic profiles and/or peptide maps of half-syctine-containing peptides. The spores of the mutants of both classes were sensitive to lysozyme and failed to respond to the germinants L-alanine plus adenosine. The spores were also more sensitive to octanol than the parental strain, but contained the same amount of dipicolinic acid and were equally heat resistant. The reversion frequencies in both cases were consistent with an initial point mutation, suggesting that an alteration in the major coat polypeptide accounted for the phenotypic properties studied. Images PMID:806578

  4. Retrotransposon-induced ectopic expression of cut causes the Om(1A) mutant in Drosophila ananassae.

    PubMed

    Awasaki, T; Juni, N; Hamabata, T; Yoshida, K; Matsuda, M; Tobari, Y N; Hori, S H

    1994-05-01

    Optic morphology (Om) mutations in Drosophila ananassae map to at least 22 loci scattered throughout the genome. They are semidominant, neomorphic, nonpleiotropic, and are associated with the insertion of a retrotransposon, tom. The Om(1A) gene, which is cytogenetically linked to the cut locus, was cloned using a DNA fragment of the cut locus of Drosophila melanogaster as a probe. Three of the eight alleles of Om(1A) examined have insertion of the tom element within a putative cut region. The gamma-ray-induced revertants of Om(1A) are accompanied with cut lethal mutations and rearrangements within the cut coding region. In the eye imaginal discs of the Om(1A) mutants, differentiation of photoreceptor clusters is suppressed, abnormal cell death occurs in the center and the cut protein is expressed ectopically. D. melanogaster flies transformed with a chimeric cut gene under the control of a heat-inducible promoter show excessive cell death in the region anterior to the morphogenetic furrow, suppressed differentiation to photoreceptor clusters and defect in the imaginal eye morphology when subjected to temperature elevation. These findings suggest that the tom element inserted within the Om(1A) region induces ectopic cut expression in the eye imaginal discs, thus resulting in the Om(1A) mutant phenotype. PMID:8056307

  5. Retrotransposon-Induced Ectopic Expression of Cut Causes the Om(1a) Mutant in Drosophila Ananassae

    PubMed Central

    Awasaki, T.; Juni, N.; Hamabata, T.; Yoshida, K.; Matsuda, M.; Tobari, Y. N.; Hori, S. H.

    1994-01-01

    Optic morphology (Om) mutations in Drosophila ananassae map to at least 22 loci scattered throughout the genome. They are semidominant, neomorphic, nonpleiotropic, and are associated with the insertion of a retrotransposon, tom. The Om(1A) gene, which is cytogenetically linked to the cut locus, was cloned using a DNA fragment of the cut locus of Drosophila melanogaster as a probe. Three of the eight alleles of Om(1A) examined have insertion of the tom element within a putative cut region. The ?-ray-induced revertants of Om(1A) are accompanied with cut lethal mutations and rearrangements within the cut coding region. In the eye imaginal discs of the Om(1A) mutants, differentiation of photoreceptor clusters is suppressed, abnormal cell death occurs in the center and the cut protein is expressed ectopically. D. melanogaster flies transformed with a chimeric cut gene under the control of a heat-inducible promoter show excessive cell death in the region anterior to the morphogenetic furrow, suppressed differentiation to photoreceptor clusters and defect in the imaginal eye morphology when subjected to temperature elevation. These findings suggest that the tom element inserted within the Om(1A) region induces ectopic cut expression in the eye imaginal discs, thus resulting in the Om(1A) mutant phenotype. PMID:8056307

  6. Characterization of Triosephosphate Isomerase Mutants with Reduced Enzyme Activity in Mus Musculus

    PubMed Central

    Merkle, S.; Pretsch, W.

    1989-01-01

    Four heterozygous triosephosphate isomerase (TPI) mutants with approximately 50% reduced activity in blood compared to wild type were detected in offspring of 1-ethyl-1-nitrosourea treated male mice. Breeding experiments displayed an autosomal, dominant mode of inheritance for the mutations. All mutations were found to be homozygous lethal at an early postimplantation stage of embryonic development, probably due to a total lack of TPI activity and consequently to the inability to utilize glucose as a source of metabolic energy. Although activity alteration was also found in liver, lung, kidney, spleen, heart, brain and muscle the TPI deficiency in heterozygotes has no influence on the following physiological traits: hematological parameters, plasma glucose, glucose consumption of blood cells, body weight and organo-somatic indices of liver, spleen, heart, kidney and lung. Biochemical investigations of TPI in the four mutant lines indicated no difference of physicochemical properties compared to the wild type. Results from immunoinactivation assays indicate that the decrease of enzyme activity corresponds to a decrease in the level of an immunologically active moiety. It is suggested that the mutations have affected the Tpi-1 structural locus and resulted in alleles which produce no detectable enzyme activity and no immunologically cross-reacting material. The study furthermore suggests one functional TPI gene per haploid genome in the erythrocyte and seven other tested organs of the mouse. PMID:2693209

  7. Native Mutant Huntingtin in Human Brain

    PubMed Central

    Sapp, Ellen; Valencia, Antonio; Li, Xueyi; Aronin, Neil; Kegel, Kimberly B.; Vonsattel, Jean-Paul; Young, Anne B.; Wexler, Nancy; DiFiglia, Marian

    2012-01-01

    Huntington disease (HD) is caused by polyglutamine expansion in the N terminus of huntingtin (htt). Analysis of human postmortem brain lysates by SDS-PAGE and Western blot reveals htt as full-length and fragmented. Here we used Blue Native PAGE (BNP) and Western blots to study native htt in human postmortem brain. Antisera against htt detected a single band broadly migrating at 575–850 kDa in control brain and at 650–885 kDa in heterozygous and Venezuelan homozygous HD brains. Anti-polyglutamine antisera detected full-length mutant htt in HD brain. There was little htt cleavage even if lysates were pretreated with trypsin, indicating a property of native htt to resist protease cleavage. A soluble mutant htt fragment of about 180 kDa was detected with anti-htt antibody Ab1 (htt-(1–17)) and increased when lysates were treated with denaturants (SDS, 8 m urea, DTT, or trypsin) before BNP. Wild-type htt was more resistant to denaturants. Based on migration of in vitro translated htt fragments, the 180-kDa segment terminated ?htt 670–880 amino acids. If second dimension SDS-PAGE followed BNP, the 180-kDa mutant htt was absent, and 43–50 kDa htt fragments appeared. Brain lysates from two HD mouse models expressed native full-length htt; a mutant fragment formed if lysates were pretreated with 8 m urea + DTT. Native full-length mutant htt in embryonic HD140Q/140Q mouse primary neurons was intact during cell death and when cell lysates were exposed to denaturants before BNP. Thus, native mutant htt occurs in brain and primary neurons as a soluble full-length monomer. PMID:22375012

  8. Structural Basis for Potent Cross-Neutralizing Human Monoclonal Antibody Protection against Lethal Human and Zoonotic Severe Acute Respiratory Syndrome Coronavirus Challenge?

    PubMed Central

    Rockx, Barry; Corti, Davide; Donaldson, Eric; Sheahan, Timothy; Stadler, Konrad; Lanzavecchia, Antonio; Baric, Ralph

    2008-01-01

    Severe acute respiratory syndrome coronavirus (SARS-CoV) emerged in 2002, and detailed phylogenetic and epidemiological analyses have suggested that it originated from animals. The spike (S) glycoprotein has been identified as a major component of protective immunity, and 23 different amino acid changes were noted during the expanding epidemic. Using a panel of SARS-CoV recombinants bearing the S glycoproteins from isolates representing the zoonotic and human early, middle, and late phases of the epidemic, we identified 23 monoclonal antibodies (MAbs) with neutralizing activity against one or multiple SARS-CoV spike variants and determined the presence of at least six distinct neutralizing profiles in the SARS-CoV S glycoprotein. Four of these MAbs showed cross-neutralizing activity against all human and zoonotic S variants in vitro, and at least three of these were mapped in distinct epitopes using escape mutants, structure analyses, and competition assays. These three MAbs (S109.8, S227.14, and S230.15) were tested for use in passive vaccination studies using lethal SARS-CoV challenge models for young and senescent mice with four different homologous and heterologous SARS-CoV S variants. Both S227.14 and S230.15 completely protected young and old mice from weight loss and virus replication in the lungs for all viruses tested, while S109.8 completely protected mice from weight loss and clinical signs in the presence of viral titers. We conclude that a single human MAb can confer broad protection against lethal challenge with multiple zoonotic and human SARS-CoV isolates, and we identify a robust cocktail formulation that targets distinct epitopes and minimizes the likely generation of escape mutants. PMID:18199635

  9. A lethal de novo mutation in the middle domain of the dynamin-related GTPase Drp1 impairs higher order assembly and mitochondrial division.

    PubMed

    Chang, Chuang-Rung; Manlandro, Cara Marie; Arnoult, Damien; Stadler, Julia; Posey, Ammon E; Hill, R Blake; Blackstone, Craig

    2010-10-15

    Mitochondria dynamically fuse and divide within cells, and the proper balance of fusion and fission is necessary for normal mitochondrial function, morphology, and distribution. Drp1 is a dynamin-related GTPase required for mitochondrial fission in mammalian cells. It harbors four distinct domains: GTP-binding, middle, insert B, and GTPase effector. A lethal mutation (A395D) within the Drp1 middle domain was reported in a neonate with microcephaly, abnormal brain development, optic atrophy, and lactic acidemia (Waterham, H. R., Koster, J., van Roermund, C. W., Mooyer, P. A., Wanders, R. J., and Leonard, J. V. (2007) N. Engl. J. Med. 356, 1736-1741). Mitochondria within patient-derived fibroblasts were markedly elongated, but the molecular mechanisms underlying these findings were not demonstrated. Because the middle domain is particularly important for the self-assembly of some dynamin superfamily proteins, we tested the hypothesis that this A395D mutation, and two other middle domain mutations (G350D, G363D) were important for Drp1 tetramerization, higher order assembly, and function. Although tetramerization appeared largely intact, each of these mutations compromised higher order assembly and assembly-dependent stimulation of Drp1 GTPase activity. Moreover, mutant Drp1 proteins exhibited impaired localization to mitochondria, indicating that this higher order assembly is important for mitochondrial recruitment, retention, or both. Overexpression of these middle domain mutants markedly inhibited mitochondrial division in cells. Thus, the Drp1 A395D lethal defect likely resulted in impaired higher order assembly of Drp1 at mitochondria, leading to decreased fission, elongated mitochondria, and altered cellular distribution of mitochondria. PMID:20696759

  10. A small heat shock protein enables Escherichia coli to grow at a lethal temperature of 50°C conceivably by maintaining cell envelope integrity.

    PubMed

    Ezemaduka, Anastasia N; Yu, Jiayu; Shi, Xiaodong; Zhang, Kaiming; Yin, Chang-Cheng; Fu, Xinmiao; Chang, Zengyi

    2014-06-01

    It is essential for organisms to adapt to fluctuating growth temperatures. Escherichia coli, a model bacterium commonly used in research and industry, has been reported to grow at a temperature lower than 46.5°C. Here we report that the heterologous expression of the 17-kDa small heat shock protein from the nematode Caenorhabditis elegans, CeHSP17, enables E. coli cells to grow at 50°C, which is their highest growth temperature ever reported. Strikingly, CeHSP17 also rescues the thermal lethality of an E. coli mutant deficient in degP, which encodes a protein quality control factor localized in the periplasmic space. Mechanistically, we show that CeHSP17 is partially localized in the periplasmic space and associated with the inner membrane of E. coli, and it helps to maintain the cell envelope integrity of the E. coli cells at the lethal temperatures. Together, our data indicate that maintaining the cell envelope integrity is crucial for the E. coli cells to grow at high temperatures and also shed new light on the development of thermophilic bacteria for industrial application. PMID:24659772

  11. A Small Heat Shock Protein Enables Escherichia coli To Grow at a Lethal Temperature of 50°C Conceivably by Maintaining Cell Envelope Integrity

    PubMed Central

    Ezemaduka, Anastasia N.; Yu, Jiayu; Shi, Xiaodong; Zhang, Kaiming; Yin, Chang-Cheng

    2014-01-01

    It is essential for organisms to adapt to fluctuating growth temperatures. Escherichia coli, a model bacterium commonly used in research and industry, has been reported to grow at a temperature lower than 46.5°C. Here we report that the heterologous expression of the 17-kDa small heat shock protein from the nematode Caenorhabditis elegans, CeHSP17, enables E. coli cells to grow at 50°C, which is their highest growth temperature ever reported. Strikingly, CeHSP17 also rescues the thermal lethality of an E. coli mutant deficient in degP, which encodes a protein quality control factor localized in the periplasmic space. Mechanistically, we show that CeHSP17 is partially localized in the periplasmic space and associated with the inner membrane of E. coli, and it helps to maintain the cell envelope integrity of the E. coli cells at the lethal temperatures. Together, our data indicate that maintaining the cell envelope integrity is crucial for the E. coli cells to grow at high temperatures and also shed new light on the development of thermophilic bacteria for industrial application. PMID:24659772

  12. The global translation profile in a ribosomal protein mutant resembles that of an eIF3 mutant

    PubMed Central

    2013-01-01

    Background Genome-wide assays performed in Arabidopsis and other organisms have revealed that the translation status of mRNAs responds dramatically to different environmental stresses and genetic lesions in the translation apparatus. To identify additional features of the global landscape of translational control, we used microarray analysis of polysomal as well as non-polysomal mRNAs to examine the defects in translation in a poly(A) binding protein mutant, pab2 pab8, as well as in a mutant of a large ribosomal subunit protein, rpl24b/shortvalve1. Results The mutation of RPL24B stimulated the ribosome occupancy of mRNAs for nuclear encoded ribosomal proteins. Detailed analysis yielded new insights into the translational regulon containing the ribosomal protein mRNAs. First, the ribosome occupancy defects in the rpl24b mutant partially overlapped with those in a previously analyzed initiation factor mutant, eif3h. Second, a group of mRNAs with incomplete coding sequences appeared to be uncoupled from the regulon, since their dependence on RPL24B differed from regular mRNAs. Third, different sister paralogs of the ribosomal proteins differed in their translation state in the wild-type. Some sister paralogs also differed in their response to the rpl24b mutation. In contrast to rpl24b, the pab2 pab8 mutant revealed few gene specific translational defects, but a group of seed storage protein mRNAs were stimulated in their ribosome occupancy. In the course of this work, while optimizing the statistical analysis of ribosome occupancy data, we collected 12 biological replicates of translation states from wild-type seedlings. We defined 20% of mRNAs as having a high variance in their translation state. Many of these mRNAs were functionally associated with responses to the environment, suggesting that subtle variation in the environmental conditions is sensed by plants and transduced to affect the translational efficiency of hundreds of mRNAs. Conclusions These data represent the first genome-wide analysis of translation in a eukaryote defective in the large ribosomal subunit. RPL24 and eIF3h play similar but non-identical roles in eukaryotic translation. The data also shed light on the fine structure of the regulon of ribosomal protein mRNAs. PMID:24377433

  13. Mutations in the glutamine synthetase I (gsI) gene produce embryo-lethal female sterility in Drosophila melanogaster.

    PubMed

    Caggese, C; Caizzi, R; Barsanti, P; Bozzetti, M P

    1992-01-01

    A female-sterile mutation (fs(2) PM11-19) was recovered in a screen for P-M hybrid dysgenesis induced mutations uncovered by a deletion of region 21B and was identified as an allele of the gene encoding the Drosophila glutamine synthetase I (GSI) mitochondrial isozyme. Molecular analysis has shown that fs(2)PM11-19 contains a 5 kb insert within 500 bp upstream of the transcriptional start site of the gsI gene. Mutant flies have extremely low levels of gsI transcription and GSI activity. A pre-existing deficiency (Df(2L) netPM1) with a breakpoint near the transcription start site was also found to be a female-sterile allele of gsI. All eggs laid by PM11-19 homozygous females, as well as by females heterozygous for this mutation and a deletion or any of several recessive lethal alleles of the gsI gene, fail to hatch. We conclude that an adequate level of maternally supplied GSI activity is necessary in the early stages of Drosophila embryonic development. PMID:1363402

  14. Breakthrough of ultraviolet light from various brands of fluorescent lamps: lethal effects on DNA repair-defective bacteria.

    PubMed

    Hartman, P E; Biggley, W H

    1996-01-01

    In a comparative study of 17 pairs of 15 W fluorescent lamps intended for use in homes and purchased in local stores, we detect over 10-fold differences in UVB + UVC emissions between various lamps. This breakthrough of ultraviolet (UV) light is in part correlated with ability of lamps to kill DNA repair-defective recA-uvrB- Salmonella. Relative proficiency of lamps in eliciting photoreactivation of UV-induced DNA lesions also plays a prominent role in the relative rates of bacterial inactivation by emissions from different lamps. Lamps made in Chile, such as Philips brand lamps and one type of General Electric lamp, produce far less UVB + UVC and fail to kill recA-uvrB- bacteria. In contrast, all tested lamps manufactured in the USA, Hungary, and Japan exhibit readily observed deleterious biological effects. When an E. coli recA-uvrB-phr- (photolyase-negative) triple mutant is used for assay, lethal radiations are detected from all lamps, and single-hit exponential inactivation rates rather closely correlate to amount of directly measured UVB + UVC output of each pair of lamps. Although all lamps tested may meet international and United States standards for radiation safety, optimal practices in lamp manufacture are clearly capable of decreasing human exposure to indoor UV light. PMID:8665873

  15. Vibrio cholerae Exploits Sub-Lethal Concentrations of a Competitor-Produced Antibiotic to Avoid Toxic Interactions

    PubMed Central

    Graff, Jason R.; Forschner-Dancause, Stephanie R.; Menden-Deuer, Susanne; Long, Richard A.; Rowley, David C.

    2012-01-01

    Vibrio cholerae is a human pathogenic marine bacterium inhabiting coastal regions and is vectored into human food and water supplies via attachment to particles including detritus, phytoplankton, and zooplankton. Particle colonization by the pathogen is inhibited by an antagonistic interaction with the particle-associated Vibrionales bacterium SWAT3, a producer of the antibiotic andrimid. By analyzing the individual movement behaviors of V. cholerae exposed to a gradient of andrimid in a microfluidics device, we show that the pathogen has a concentration dependent avoidance response to sub-lethal concentrations of the pure antibiotic and to the metabolites produced by a growing colony of SWAT3-wild-type. This avoidance behavior includes a 25% increase in swimming speeds, 30% increase in run lengths, and a shift in the direction of the bacteria away from the andrimid source. Consequently, these behavioral shifts at low concentrations of andrimid would lead to higher diffusivity and result in the dispersion of bacteria away from the competitor and source of the antibiotic. Such alterations in motility were not elicited in response to a non-andrimid-producing SWAT3 mutant, suggesting andrimid may be a negative effector of chemotaxis for V. cholerae. The behavioral response of colonizing bacteria to sub-inhibitory concentrations of competitor-produced antibiotics is one mechanism that can influence microbial diversity and interspecific competition on particles, potentially affecting human health in coastal communities and element cycling in the ocean. PMID:23386845

  16. Pathogenesis of defined invasion mutants of Yersinia enterocolitica in a BALB/c mouse model of infection.

    PubMed Central

    Pepe, J C; Wachtel, M R; Wagar, E; Miller, V L

    1995-01-01

    It has been hypothesized for many years that the ability of Yersinia spp. to invade tissue culture cells is reflective of their ability to penetrate the intestinal epithelium and that this capacity is an important aspect of the disease process. Three different genes from Yersinia spp. that are involved in the tissue culture invasion phenotype have been identified: inv, ail, and yadA. It was previously shown that inv is necessary for efficient penetration of the intestinal epithelium by Yersinia enterocolitica. The present study was initiated to determine whether other known Yersinia invasion factors could promote uptake of the bacteria by mice in the absence of invasion. In addition, the roles of these three invasion factors in the survival of the bacteria, lethality for mice, and development of pathology were compared. We found that YadA is necessary for persistence of Y. enterocolitica in Peyer's patches, and consistent with this observation, the yadA mutant was avirulent for mice infected either orally or intraperitoneally. In addition, the inv yadA double mutant was avirulent. Histological and immunohistological examination of the Peyer's patches of infected mice indicated that despite the presence of large numbers of CFU at 24 h the yadA and ail yadA mutants cause only minimal pathology and recruitment of macrophages. At 42 h postinfection, Peyer's patches from mice infected with the inv mutant showed no pathology, despite the prediction that some of the mice by this time would be colonized. However, at 72 h, inflammation and necrosis were evident in some Peyer's patches. Together, these observations suggest that for visible pathology to develop, a threshold number of bacteria (> 10(5)) is needed and the bacteria need to persist for more than 24 h. Lastly, YadA but not Ail may play a role in the less efficient, delayed invasion of the intestinal epithelium observed for the inv mutant. PMID:7591144

  17. Agravitropic mutants of the moss Ceratodon purpureus do not complement mutants having a reversed gravitropic response.

    PubMed

    Cove, David J; Quatrano, Ralph S

    2006-07-01

    New mutants of the moss Ceratodon purpureus have been isolated, which showed abnormal gravitropic responses. The apical cells of protonemal filaments of wild-type strains respond to gravity by growing upwards and are well aligned to the gravity vector. This response only occurs in darkness. Mutants show a range of phenotypes. Some are insensitive to gravity, showing symmetrical growth, while others align to the gravity vector but orient growth downwards. A further class grows in darkness as though it were in light, showing insensitivity to gravity and continued chlorophyll synthesis. Somatic hybrids between mutants and wild-type strains and between pairs of mutants have been selected using transgenic antibiotic resistance as selective markers. Hybrids between wild-type strains and all of the mutants have a wild-type phenotype, and so all mutants therefore have recessive phenotypes. Mutants comprise three complementation groups. One group has a single member, while another has three members. The third has at least 16 members and shows a complex pattern of complementation consistent with a single gene product functioning in both orientation and alignment to gravity, as well as contributing more than one subunit to the mature product. PMID:17080959

  18. Mutants of Discosoma red uorescent protein with a GFP-like chromophore

    E-print Network

    Steipe, Boris

    the GFP-like absorption band in the mutant proteins produces both green and red fluorescence. Upon unfolding and heating, the absorption spectrum of the RFP chromophore slowly becomes similar the unfolded protein under various conditions. Finally, we performed a random mutagen- esis of the RFP gene

  19. An ordered, nonredundant library of Pseudomonas aeruginosa strain PA14 transposon insertion mutants

    E-print Network

    Ausubel, Frederick M.

    experimental conditions. A public, internet-accessible database (the PA14 Transposon Insertion Mu- tantAn ordered, nonredundant library of Pseudomonas aeruginosa strain PA14 transposon insertion mutants. Ausubel, December 22, 2005 Random transposon insertion libraries have proven invaluable in studying

  20. ProTherm, version 4.0: thermodynamic database for proteins and mutants

    Microsoft Academic Search

    K. Abdulla Bava; M. Michael Gromiha; Hatsuho Uedaira; Koji Kitajima; Akinori Sarai

    2004-01-01

    Release 4.0 of ProTherm, thermodynamic database for proteins and mutants, contains ~14 500 numer- ical data (~450% of the first version) of several thermodynamic parameters along with experimental methods and conditions, and structural, functional and literature information. The sequence and struc- tural information of proteins is connected with thermodynamic data through links between entries in Protein Data Bank, Protein Information

  1. Lethal effects on different marine organisms, associated with sediment-seawater acidification deriving from CO2 leakage.

    PubMed

    Basallote, M D; Rodríguez-Romero, A; Blasco, J; DelValls, A; Riba, I

    2011-08-01

    CO(2) leakages during carbon capture and storage in sub-seabed geological structures could produce potential impacts on the marine environment. To study lethal effects on marine organisms attributable to CO(2) seawater acidification, a bubbling CO(2) system was designed enabling a battery of different tests to be conducted, under laboratory conditions, employing various pH treatments (8.0, 7.5, 7.0, 6.5, 6.0, and 5.5). Assays were performed of three exposure routes (seawater, whole sediment, and sediment elutriate). Individuals of the clam (Ruditapes philippinarum) and early-life stages of the gilthead seabream, Sparus aurata, were exposed for 10 days and 72 h, respectively, to acidified clean seawater. S. aurata larvae were also exposed to acidified elutriate samples, and polychaete organisms of the specie Hediste diversicolor and clams R. philippinarum were also exposed for 10 days to estuarine whole sediment. In the fish larvae elutriate test, 100 % mortality was recorded at pH 6.0, after 48 h of exposure. Similar results were obtained in the clam sediment exposure test. In the other organisms, significant mortality (p?lethal effects (calculating L[H(+)]50, defined as the H(+) concentration that causes lethal effects in 50 % of the population exposed) were detected in association with the lowest pH treatment for all the species. The implication of these results is that a severe decrease of seawater pH would cause high mortality in marine organisms of several different kinds and life stages. The study addresses the potential risks incurred due to CO(2) leakages in marine environments. PMID:22828884

  2. A ?dinB mutation that sensitizes Escherichia coli to the lethal effects of UV and X-radiation

    PubMed Central

    Lee, Mei-Chong W.; Franco, Magdalena; Vargas, Doris M.; Hudman, Deborah A.; White, Steven J.; Fowler, Robert G.; Sargentini, Neil J.

    2014-01-01

    The DinB (PolIV) protein of Escherichia coli participates in several cellular functions. We investigated a dinB mutation, ?(dinB-yafN)883(::kan) [referred to as ?dinB883], which strongly sensitized E. coli cells to both UV- and X-radiation killing. Earlier reports indicated dinB mutations had no obvious effect on UV radiation sensitivity which we confirmed by showing that normal UV radiation sensitivity is conferred by the ?dinB749 allele. Compared to a wild-type strain, the ?dinB883 mutant was most sensitive (160-fold) in early to mid-logarithmic growth phase and much less sensitive (twofold) in late log or stationary phases, thus showing a growth phase-dependence for UV radiation sensitivity. This sensitizing effect of ?dinB883 is assumed to be completely dependent upon the presence of UmuDC protein; since the ?dinB883 mutation did not sensitize the ?umuDC strain to UV radiation killing throughout log phase and early stationary phase growth. The DNA damage checkpoint activity of UmuDC was clearly affected by ?dinB883 as shown by testing a umuC104 ?dinB883 double-mutant. The sensitivities of the ?umuDC strain and the ?dinB883 ?umuDC double-mutant strain were significantly greater than for the ?dinB883 strain, suggesting that the ?dinB883 allele only partially suppresses UmuDC activity. The ?dinB883 mutation partially sensitized (fivefold) uvrA and uvrB strains to UV radiation, but did not sensitize a ?recA strain. A comparison of the DNA sequences of the ?dinB883 allele with the sequences of the ?(dinB-yafN)882(::kan) and ?dinB749 alleles, which do not sensitize cells to UV radiation, revealed ?dinB883 is likely a “gain-of-function” mutation. The ?dinB883 allele encodes the first 54 amino acids of wild-type DinB followed by 29 predicted residues resulting from the continuation of the dinB reading frame into an adjacent insertion fragment. The resulting polypeptide is proposed to interfere directly or indirectly with UmuDC function(s) involved in protecting cells against the lethal effects of radiation. PMID:24657250

  3. Pegfilgrastim Improves Survival of Lethally Irradiated Nonhuman Primates.

    PubMed

    Hankey, Kim G; Farese, Ann M; Blaauw, Erica C; Gibbs, Allison M; Smith, Cassandra P; Katz, Barry P; Tong, Yan; Prado, Karl L; MacVittie, Thomas J

    2015-06-01

    Leukocyte growth factors (LGF), such as filgrastim, pegfilgrastim and sargramostim, have been used to mitigate the hematologic symptoms of acute radiation syndrome (ARS) after radiation accidents. Although these pharmaceuticals are currently approved for treatment of chemotherapy-induced myelosuppression, such approval has not been granted for myelosuppression resulting from acute radiation exposure. Regulatory approval of drugs used to treat radiological or nuclear exposure injuries requires their development and testing in accordance with the Animal Efficacy Rule, set forth by the U.S. Food and Drug Administration. To date, filgrastim is the only LGF that has undergone efficacy assessment conducted under the Animal Efficacy Rule. To confirm the efficacy of another LGF with a shorter dosing regimen compared to filgrastim, we evaluated the use of pegfilgrastim (Neulasta®) in a lethal nonhuman primate (NHP) model of hematopoietic acute radiation syndrome (H-ARS). Rhesus macaques were exposed to 7.50 Gy total-body irradiation (the LD50/60), delivered at 0.80 Gy/min using linear accelerator 6 MV photons. Pegfilgrastim (300 ?g/kg, n = 23) or 5% dextrose in water (n = 23) was administered on day 1 and 8 postirradiation and all animals received medical management. Hematologic and physiologic parameters were evaluated for 60 days postirradiation. The primary, clinically relevant end point was survival to day 60; secondary end points included hematologic-related parameters. Pegfilgrastim significantly (P = 0.0014) increased 60 day survival to 91.3% (21/23) from 47.8% (11/23) in the control. Relative to the controls, pegfilgrastim also significantly: 1. decreased the median duration of neutropenia and thrombocytopenia; 2. improved the median time to recovery of absolute neutrophil count (ANC) ?500/?L, ANC ?1,000/?L and platelet (PLT) count ?20,000/?L; 3. increased the mean ANC at nadir; and 4. decreased the incidence of Gram-negative bacteremia. These data demonstrate that pegfilgrastim is an additional medical countermeasure capable of increasing survival and neutrophil-related parameters when administered in an abbreviated schedule to a NHP model of lethal H-ARS. PMID:26035709

  4. The integration of mutant loci affecting maize endosperm development in a dense genetic map using an AFLP-based procedure

    Microsoft Academic Search

    Luca Pasini; Maria Rosaria Stile; Enrico Puja; Rita Valsecchi; Priscilla Francia; Giorgia Carletti; Francesco Salamini; Adriano Marocco

    2008-01-01

    In this paper, 10 mutations conditioning the appearance of defective, miniature or collapsed endosperm, but with normal sporophyte\\u000a development, were considered. Homozygous mutant kernels have reduced grain weight, kernel size, density and, in some of these,\\u000a higher than normal seed protein content. The mutant loci were integrated into a high-resolution genetic map in order to associate\\u000a them to specific genes.

  5. Yeast glycosylation mutants are sensitive to aminoglycosides.

    PubMed Central

    Dean, N

    1995-01-01

    Aminoglycosides are a therapeutically important class of antibiotics that inhibit bacterial protein synthesis and a number of viral and eukaryotic functions by blocking RNA-protein interactions. Vanadate-resistant Saccharomyces cerevisiae mutants with defects in Golgi-specific glycosylation processes exhibit growth sensitivity to hygromycin B, an aminoglycoside [Ballou, L., Hitzeman, R. A., Lewis, M. S. & Ballou, C. E. (1991) Proc. Natl. Acad. Sci. USA 88, 3209-3212]. Here, evidence is presented that glycosylation is, in and of itself, a key factor mediating aminoglycoside sensitivity in yeast. Examination of mutants with a wide range of glycosylation abnormalities reveals that all are sensitive to aminoglycosides. This effect is specific to aminoglycosides and not merely a consequence of increased permeability of the yeast mutants to drugs. Furthermore, inhibition of glycosylation in wild-type cells leads to a marked increase in their sensitivity to aminoglycosides. These results establish that a defect in glycosylation is sufficient to render yeast cells susceptible to these clinically important drugs. Further, they suggest that a molecule which prevents the uptake or mediates removal of aminoglycosides requires glycosylation for its activity. Perhaps more importantly, this finding on drug sensitivity provides the most powerful screen to date to identify mutants and thereby to isolate genes involved in all aspects of N-linked glycosylation. Images Fig. 1 Fig. 2 Fig. 3 Fig. 4 PMID:7877969

  6. Genetic comparisons of gibberellin mutants in potato

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Gibberellin deficient mutants in potato have been published as ga1 (from S. tuberosum ssp. tuberosum and andigena), pito (from the tuberosum cultivar Pito), and ga2 (from the phureja haploid inducing clone “phu-1.22”). We conducted crossing experiments to investigate genetic similarities. When the...

  7. Post Quantum Cryptography from Mutant Prime Knots

    E-print Network

    Annalisa Marzuoli; Giandomenico Palumbo

    2010-10-11

    By resorting to basic features of topological knot theory we propose a (classical) cryptographic protocol based on the `difficulty' of decomposing complex knots generated as connected sums of prime knots and their mutants. The scheme combines an asymmetric public key protocol with symmetric private ones and is intrinsecally secure against quantum eavesdropper attacks.

  8. Ethanol production using engineered mutant E. coli

    DOEpatents

    Ingram, Lonnie O. (Gainesville, FL); Clark, David P. (Carbondale, IL)

    1991-01-01

    The subject invention concerns novel means and materials for producing ethanol as a fermentation product. Mutant E. coli are transformed with a gene coding for pyruvate decarboxylase activity. The resulting system is capable of producing relatively large amounts of ethanol from a variety of biomass sources.

  9. Dimerization specificities of leucine zipper mutants

    E-print Network

    Rieker, Jennifer Dawn

    2013-02-22

    The dimerization specificity of a leucine zipper is partially determined by the interactions of charged amino acids on the surfaces of dimer interfaces (e and g positions). A series of e and g position GCN4 mutants has been described that do...

  10. Retrocyclins Kill Bacilli and Germinating Spores of Bacillus anthracis and Inactivate Anthrax Lethal Toxin*

    PubMed Central

    Wang, Wei; Mulakala, Chandrika; Ward, Sabrina C.; Jung, Grace; Luong, Hai; Pham, Duy; Waring, Alan J.; Kaznessis, Yiannis; Lu, Wuyuan; Bradley, Kenneth A.; Lehrer, Robert I.

    2008-01-01

    ?-defensins are cyclic octadecapeptides encoded by the modified ?-defensin genes of certain nonhuman primates. The recent demonstration that human ?-defensins could prevent deleterious effects of anthrax lethal toxin in vitro and in vivo led us to examine the effects of ?-defensins on Bacillus anthracis (Sterne). We tested rhesus ?-defensins 1–3, retrocyclins 1–3, and several analogues of RC-1. Low concentrations of ?-defensins not only killed vegetative cells of B. anthracis (Sterne) and rendered their germinating spores nonviable, they also inactivated the enzymatic activity of anthrax lethal factor and protected murine RAW-264.7 cells from lethal toxin, a mixture of lethal factor and protective antigen. Structure-function studies indicated that the cyclic backbone, intramolecular tri-disulfide ladder, and arginine residues of ?-defensins contributed substantially to these protective effects. Surface plasmon resonance studies showed that retrocyclins bound the lethal factor rapidly and with high affinity. Retrocyclin-mediated inhibition of the enzymatic activity of lethal factor increased substantially if the enzyme and peptide were preincubated before substrate was added. The temporal discrepancy between the rapidity of binding and the slowly progressive extent of lethal factor inhibition suggest that post-binding events, perhaps in situ oligomerization, contribute to the antitoxic properties of retrocyclins. Overall, these findings suggest that ?-defensins provide molecular templates that could be used to create novel agents effective against B. anthracis and its toxins. PMID:16790431

  11. Retrocyclins kill bacilli and germinating spores of Bacillus anthracis and inactivate anthrax lethal toxin.

    PubMed

    Wang, Wei; Mulakala, Chandrika; Ward, Sabrina C; Jung, Grace; Luong, Hai; Pham, Duy; Waring, Alan J; Kaznessis, Yiannis; Lu, Wuyuan; Bradley, Kenneth A; Lehrer, Robert I

    2006-10-27

    Theta-defensins are cyclic octadecapeptides encoded by the modified alpha-defensin genes of certain nonhuman primates. The recent demonstration that human alpha-defensins could prevent deleterious effects of anthrax lethal toxin in vitro and in vivo led us to examine the effects of theta-defensins on Bacillus anthracis (Sterne). We tested rhesus theta-defensins 1-3, retrocyclins 1-3, and several analogues of RC-1. Low concentrations of theta-defensins not only killed vegetative cells of B. anthracis (Sterne) and rendered their germinating spores nonviable, they also inactivated the enzymatic activity of anthrax lethal factor and protected murine RAW-264.7 cells from lethal toxin, a mixture of lethal factor and protective antigen. Structure-function studies indicated that the cyclic backbone, intramolecular tri-disulfide ladder, and arginine residues of theta-defensins contributed substantially to these protective effects. Surface plasmon resonance studies showed that retrocyclins bound the lethal factor rapidly and with high affinity. Retrocyclin-mediated inhibition of the enzymatic activity of lethal factor increased substantially if the enzyme and peptide were preincubated before substrate was added. The temporal discrepancy between the rapidity of binding and the slowly progressive extent of lethal factor inhibition suggest that post-binding events, perhaps in situ oligomerization, contribute to the antitoxic properties of retrocyclins. Overall, these findings suggest that theta-defensins provide molecular templates that could be used to create novel agents effective against B. anthracis and its toxins. PMID:16790431

  12. An attenuated mutant of avian pathogenic Escherichia coli serovar O78: a possible live vaccine strain for prevention of avian colibacillosis.

    PubMed

    Nagano, Tetsuji; Kitahara, Rie; Nagai, Shinya

    2012-09-01

    Here construction of an attenuated mutant of an avian pathogenic Escherichia coli serovar O78 using an allelic exchange procedure is described. The mutant AESN1331, which carries a deletion in the crp gene, lost tryptophan deaminase activity and therefore lacked the ability to produce indole. The mutant strain additionally lacked the ability to adsorb Congo red, no longer fermented sugars other than glucose and L-arabinose, did not harbor four known virulence-associated genes (iss, tsh, cvaA, papC), and was susceptible to many antimicrobials, with the exception of nalidixic acid. The lethal dose (LD(50) value) of the mutant strain on intravenous challenge in chickens was approximately 10-fold higher than that of the parent strain. Additionally, the mutant strain was rapidly eliminated from chickens, being detected in the respiratory tract only on the first day post-inoculation by fine spray. Administration of the mutant strain via various routes such as spray and eye drop for chickens, as well as in ovo inoculation for embryonated egg, evoked an effective immune response that protected against a virulent wild-type E. coli O78 strain. Specifically, after immunization with the mutant strain, chickens challenged intravenously with an E. coli O78 strain exhibited decreases in mortality, clinical scores, organ lesion scores, and recovery of the challenge strain from organs compared to non-immunized chickens. These findings suggest that AESN1331 is a suitable candidate for a live vaccine strain to protect chickens from colibacillosis caused by avian E. coli O78. PMID:22708916

  13. General formulation of Luria-Delbr{\\"u}ck distribution of the number of mutants

    E-print Network

    Houchmandzadeh, Bahram

    2015-01-01

    The Luria-Delbr{\\"u}ck experiment is a cornerstone of evolutionary theory, demonstrating the ran-domness of mutations before selection. The distribution of the number of mutants in this experiment has been the subject of intense investigation during the last 70 years. Despite this considerable effort, most of the results have been obtained under the assumption of constant growth rate, which is far from the experimental condition. We derive here the properties of this distribution for arbitrary growth function, for both the deterministic and stochastic growth of the mutants. The derivation we propose is surprisingly simple and versatile, allowing many generalizations to be taken easily into account.

  14. Biotransformation of ethanol to acetaldehyde by wild and mutant strains of methylotrophic yeast

    SciTech Connect

    Moroz, O.M.; Sibirnyi, A.A.; Ksheminskaya, G.P. [I. Franko L`vov State Univ. (Ukraine)]|[A.V. Palladin Institute of Biochemistry (Ukraine)

    1995-05-01

    The conversion of ethanol to acetaldehyde by intact cells of wild and mutant strains of methylotrophic yeast Hansenula polymorpha was studied. It was established that mutations that lower the activity of aldehyde reductase and acetaldehyde dehydrogenase stimulate acetaldehyde accumulation. The highest accumulation of acetaldehyde was found in a mutant that possessed increased alcohol oxidase activity in growth on a medium with glucose. A decrease in formaldehyde dehydrogenase did not stimulate acetaldehyde accumulation. Bioconversion of ethanol to acetaldehyde was most effective at lowered temperatures due to marked suppression of catabolic alcohol oxidase inactivation, but not to the activity of this enzyme under indicated conditions. 27 refs., 4 figs., 3 tabs.

  15. Amino Acid Substitutions Improve the Immunogenicity of H7N7HA Protein and Protect Mice against Lethal H7N7 Viral Challenge.

    PubMed

    Kumar, Subaschandrabose Rajesh; Prabakaran, Mookkan; Ashok Raj, Kattur Venkatachalam; He, Fang; Kwang, Jimmy

    2015-01-01

    Avian influenza A H7N7/NL/219/03 virus creates a serious pandemic threat to human health because it can transmit directly from domestic poultry to humans and from human to human. Our previous vaccine study reported that mice when immunized intranasally (i.n) with live Bac-HA were protected from lethal H7N7/NL/219/03 challenge, whereas incomplete protection was obtained when administered subcutaneously (s.c) due to the fact that H7N7 is a poor inducer of neutralizing antibodies. Interestingly, our recent vaccine studies reported that mice when vaccinated subcutaneously with Bac-HA (H7N9) was protected against both H7N9 (A/Sh2/2013) and H7N7 virus challenge. HA1 region of both H7N7 and H7N9 viruses are differ at 15 amino acid positions. Among those, we selected three amino acid positions (T143, T198 and I211) in HA1 region of H7N7. These amino acids are located within or near the receptor binding site. Following the selection, we substituted the amino acid at these three positions with amino acids found on H7N9HA wild-type. In this study, we evaluate the impact of amino acid substitutions in the H7N7 HA-protein on the immunogenicity. We generated six mutant constructs from wild-type influenza H7N7HA cDNA by site directed mutagenesis, and individually expressed mutant HA protein on the surface of baculovirus (Bac-HAm) and compared their protective efficacy of the vaccines with Bac-H7N7HA wild-type (Bac-HA) by lethal H7N7 viral challenge in a mouse model. We found that mice immunized subcutaneously with Bac-HAm constructs T143A or T198A-I211V or I211V-T143A serum showed significantly higher hemagglutination inhibition and neutralization titer against H7N7 and H7N9 viruses when compared to Bac-HA vaccinated mice groups. We also observed low level of lung viral titer, negligible weight loss and complete protection against lethal H7N7 viral challenge. Our results indicated that amino acid substitution at position 143 or 211 improve immunogenicity of H7N7HA vaccine against H7N7/NL/219/03 virus. PMID:26030920

  16. Amino Acid Substitutions Improve the Immunogenicity of H7N7HA Protein and Protect Mice against Lethal H7N7 Viral Challenge

    PubMed Central

    Ashok raj, Kattur Venkatachalam; He, Fang; Kwang, Jimmy

    2015-01-01

    Avian influenza A H7N7/NL/219/03 virus creates a serious pandemic threat to human health because it can transmit directly from domestic poultry to humans and from human to human. Our previous vaccine study reported that mice when immunized intranasally (i.n) with live Bac-HA were protected from lethal H7N7/NL/219/03 challenge, whereas incomplete protection was obtained when administered subcutaneously (s.c) due to the fact that H7N7 is a poor inducer of neutralizing antibodies. Interestingly, our recent vaccine studies reported that mice when vaccinated subcutaneously with Bac-HA (H7N9) was protected against both H7N9 (A/Sh2/2013) and H7N7 virus challenge. HA1 region of both H7N7 and H7N9 viruses are differ at 15 amino acid positions. Among those, we selected three amino acid positions (T143, T198 and I211) in HA1 region of H7N7. These amino acids are located within or near the receptor binding site. Following the selection, we substituted the amino acid at these three positions with amino acids found on H7N9HA wild-type. In this study, we evaluate the impact of amino acid substitutions in the H7N7 HA-protein on the immunogenicity. We generated six mutant constructs from wild-type influenza H7N7HA cDNA by site directed mutagenesis, and individually expressed mutant HA protein on the surface of baculovirus (Bac-HAm) and compared their protective efficacy of the vaccines with Bac-H7N7HA wild-type (Bac-HA) by lethal H7N7 viral challenge in a mouse model. We found that mice immunized subcutaneously with Bac-HAm constructs T143A or T198A-I211V or I211V-T143A serum showed significantly higher hemagglutination inhibition and neutralization titer against H7N7 and H7N9 viruses when compared to Bac-HA vaccinated mice groups. We also observed low level of lung viral titer, negligible weight loss and complete protection against lethal H7N7 viral challenge. Our results indicated that amino acid substitution at position 143 or 211 improve immunogenicity of H7N7HA vaccine against H7N7/NL/219/03 virus. PMID:26030920

  17. Beta-fructofuranosidase production by 2-deoxyglucose resistant mutants of aspergillus niger in submerged and solid-state fermentation.

    PubMed

    Ashokkumar, Balasubramaniem; Gunasekaran, Paramasamy

    2002-09-01

    Aspergillus niger produces extracellular beta-fructofuranosidase under submerged (SmF) and solid state fermentation (SSF) conditions. After UV mutagenesis of conidiospores of A. niger, 2-deoxyglucose (10 g/l) resistant mutants were isolated on Czapek's minimal medium containing glycerol as a carbon source and the mutants were examined for improved production of beta-fructofuranosidase in SmF and SSF conditions. One of such mutant DGRA-1 overproduced beta-fructofuranosidase in both SmF and SSF conditions. In SmF, the mutant DGRA-1 showed higher beta-fructofuranosidase productivity (110.8 U/l/hr) than the wild type (48.3 U/l/hr). While in SSF the same strain produced 322 U/l/hr of beta-fructofuranosidase, 2 times higher than that of wild type (154.2 U/l/hr). In SmF, both wild type and mutants produced relatively low level of beta-fructofuranosidase in medium containing sucrose with glucose than from the sucrose medium. However in SSF, the DGRA-1 mutant grown in sucrose and sucrose+ glucose did not show any difference with respect to beta-fructofuranosidase production. These results indicate that the catabolite repression of beta-fructofuranosidase synthesis is observed in SmF whereas in SSF such regulation was not prominent. PMID:12587733

  18. Interferon alfacon-1 protects hamsters from lethal pichinde virus infection.

    PubMed

    Gowen, Brian B; Barnard, Dale L; Smee, Donald F; Wong, Min-Hui; Pace, Anne M; Jung, Kie-Hoon; Winslow, Scott G; Bailey, Kevin W; Blatt, Lawrence M; Sidwell, Robert W

    2005-06-01

    Hemorrhagic fever of arenaviral origin is a frequently fatal infectious disease of considerable priority to the biodefense mission. Historically, the treatment of arenaviral infections with alpha interferons has not yielded favorable results. Here we present evidence that interferon alfacon-1, a nonnaturally occurring bioengineered alpha interferon approved for the treatment of chronic hepatitis C, is active against Pichinde and Tacaribe arenaviruses in cell culture. In the hamster model of Pichinde virus (PCV) infection, interferon alfacon-1 treatment significantly protected animals from death, prolonged the survival of those that eventually died, reduced virus titers, and limited liver damage characteristic of PCV-induced disease. Moreover, interferon alfacon-1 also demonstrated therapeutic activity, to a lesser degree, when the initiation of treatment was delayed up to 2 days post-virus challenge. Despite the observed advantages of interferon alfacon-1 therapy, efforts to stimulate the immune system with the known interferon inducer poly(I:C12U) (Ampligen) offered only limited protection against lethal PCV challenge. Taken together, these data suggest that the increased potency of the bio-optimized interferon alfacon-1 molecule may be critical to the observed antiviral effects. These data are the first report demonstrating efficacious treatment of acute arenaviral disease with alpha interferon therapy, and further study is warranted. PMID:15917537

  19. Sticky foam as a less-than-lethal technology

    SciTech Connect

    Scott, S.H.

    1996-12-31

    Sandia National Labs (SNL) in 1994 completed a project funded by the National Institute of Justice (NIJ) to determine the applicability of sticky foam for correctional applications. Sticky foam is an extremely tacky, tenacious material used to block, entangle, and impair individuals. The NIJ project developed a gun capable of firing multiple shots of sticky foam, tested the gun and sticky foam effectiveness on SNL volunteers acting out prison and law enforcement scenarios, and had the gun and sticky foam evaluated by correctional representatives. Based on the NIJ project work, SNL supported the Marine Corps Mission, Operation United Shield, with sticky foam guns and supporting equipment to assist in the withdrawal of UN Peacekeepers from Somalia. Prior to the loan of the equipment, the Marines were given training in sticky foam characterization, toxicology, safety issues, cleanup and waste disposal, use limitations, use protocol and precautions, emergency facial clean-up, skin cleanup, gun filling, targeting and firing, and gun cleaning. The Marine Corps successfully used the sticky foam guns as part of that operation. This paper describes these recent developments of sticky foam for non-lethal uses and some of the lessons learned from scenario and application testing.

  20. Hemolysis-induced lethality involves inflammasome activation by heme.

    PubMed

    Dutra, Fabianno F; Alves, Letícia S; Rodrigues, Danielle; Fernandez, Patricia L; de Oliveira, Rosane B; Golenbock, Douglas T; Zamboni, Dario S; Bozza, Marcelo T

    2014-09-30

    The increase of extracellular heme is a hallmark of hemolysis or extensive cell damage. Heme has prooxidant, cytotoxic, and inflammatory effects, playing a central role in the pathogenesis of malaria, sepsis, and sickle cell disease. However, the mechanisms by which heme is sensed by innate immune cells contributing to these diseases are not fully characterized. We found that heme, but not porphyrins without iron, activated LPS-primed macrophages promoting the processing of IL-1? dependent on nucleotide-binding domain and leucine rich repeat containing family, pyrin domain containing 3 (NLRP3). The activation of NLRP3 by heme required spleen tyrosine kinase, NADPH oxidase-2, mitochondrial reactive oxygen species, and K(+) efflux, whereas it was independent of heme internalization, lysosomal damage, ATP release, the purinergic receptor P2X7, and cell death. Importantly, our results indicated the participation of macrophages, NLRP3 inflammasome components, and IL-1R in the lethality caused by sterile hemolysis. Thus, understanding the molecular pathways affected by heme in innate immune cells might prove useful to identify new therapeutic targets for diseases that have heme release. PMID:25225402

  1. Discovery and development of anthrax lethal factor metalloproteinase inhibitors.

    PubMed

    Turk, Benjamin E

    2008-02-01

    Anthrax is caused by infection with Bacillus anthracis, a spore forming, rod-shaped, encapsulated gram positive bacteria. The disease manifests itself in distinct ways depending on the route of entry of infective bacterial spores: cutaneous, inhalational, and gastrointestinal. Though rare in humans, inhalational anthrax has become a major concern due to the capacity for spores to be weaponized. The limited success of antibiotic therapy has motivated investigation of complementary therapeutic strategies that target the bacteria's secreted toxin. The zinc-dependent metalloproteinase lethal factor (LF) is a critical component of anthrax toxin and an important potential target for small molecule drugs. In the past few years, a number of approaches have been taken to identify LF inhibitors, from generating conventional metal chelating substrate analogs to random screening of diverse compound libraries. These efforts have produced several different classes of specific nanomolar range inhibitors. Some compounds have fared well in animal models for anthrax toxemia and infection, and these inhibitors and their derivatives may form the basis for future therapies to treat the disease in humans. PMID:18289054

  2. Novel repression of the glucocorticoid receptor by anthrax lethal toxin.

    PubMed

    Webster, Jeanette I; Moayeri, Mahtab; Sternberg, Esther M

    2004-06-01

    Death from anthrax has been reported to occur from systemic shock. The lethal toxin (LeTx) is the major effector of anthrax mortality. Although the mechanism of entry of this toxin into cells is well understood, its actions once inside the cell are not as well understood. LeTx is known to cleave and inactivate MAPKKs. We have recently shown that LeTx represses the glucocorticoid receptor (GR) both in vitro and in vivo. This repression is partial and specific, repressing the glucocorticoid, progesterone, and estrogen receptor alpha, but not the mineralocorticoid or estrogen receptor beta. This toxin does not affect GR ligand or DNA binding, and we have suggested that it may function by removing/inactivating one or more of the many cofactors involved in nuclear hormone receptor signaling. Although the precise involvement of this nuclear hormone receptor repression in LeTx toxicity is unknown, examples of blunted HPA axis and glucocorticoid signaling in numerous autoimmune/inflammatory diseases suggest that such repression of critically important receptors could have deleterious effects on health. PMID:15265771

  3. The anthrax lethal factor and its MAPK kinase-specific metalloprotease activity.

    PubMed

    Tonello, Fiorella; Montecucco, Cesare

    2009-12-01

    The anthrax lethal factor is a multi-domain protein toxin released by Bacillus anthracis which enters cells in a process mediated by the protective antigen and specific cell receptors. In the cytosol, the lethal factor cleaves the N-terminal tail of many MAPK kinases, thus deranging a major cell signaling pathway. The structural features at the basis of these activities of LF are reviewed here with particular attention to the proteolytic activity and to the identification of specific inhibitors. A significant similarity between the metalloprotease domain of the lethal factor and of that of the clostridial neurotoxins has been noted and is discussed. PMID:19665472

  4. Potentially-lethal damage and radioprotection in human cells exposed to californium-252

    SciTech Connect

    Schroy, C.B.; Goud, S.N.; Magura, C.; Feola, J.M.; Maruyama, Y.

    1986-01-01

    Cultured human T-1E cells were irradiated with californium-252 neutrons and gamma rays. When 2 mm caffeine was present in the medium for 47 h after irradiation cell survival (assayed by colony formation) was decreased significantly. When 2 m dimethylsulfoxide was present during the irradiations radioprotection was observed using the same assay. The caffeine data indicate that potentially-lethal lesions exist in cells after californium exposure and that these lesions can be made lethal when they would otherwise be repaired. The DMSO data indicate that radioprotection from californium exposure can be achieved and that scanvengable free radicals play an important role in Cf-252 lethality.

  5. Comparison between NOx Evolution Mechanisms of Wild-Type and nr1 Mutant Soybean Leaves 1

    PubMed Central

    Klepper, Lowell

    1990-01-01

    The nr1 soybean (Glycine max [L.] Merr.) mutant does not contain the two constitutive nitrate reductases, one of which is responsible for enzymic conversion of nitrite to NOx (NO + NO2). It was tested for possible nonenzymic NOx formation and evolution because of known chemical reactions between NO2? and plant metabolites and the instability of nitrous acid. It did not evolve NOx during the in vivo NR assay, but intact leaves did evolve small amounts of NOx under dark, anaerobic conditions. Experiments were conducted to compare NO3? reduction, NO2? accumulation, and the NOx evolution processes of the wild type (cv Williams) and the nr1 mutant. In vivo NR assays showed that wild-type leaves had three times more NO3? reducing capacity than the nr1 mutant. NOx evolution from intact, anerobic nr1 leaves was approximately 10 to 20% that from wild-type leaves. Nitrite content of the nr1 mutant leaves was usually higher than wild type due to low NOx evolution. Lag times and threshold NO2? concentrations for NOx evolution were similar for the two genotypes. While only 1 to 2% of NOx from wild type is NO2, the nr1 mutant evolved 15 to 30% NO2. The kinetic patterns of NOx evolution with time weré completely different for the mutant and wild type. Comparisons of light and heat treatments also gave very different results. It is generally accepted that the NOx evolution by wild type is primarily an enzymic conversion of NO2? to NO. However, this report concludes that NOx evolution by the nr1 mutant was due to nonenzymic, chemical reactions between plant metabolites and accumulated NO2? and/or decomposition of nitrous acid. Nonenzymic NOx evolution probably also occurs in wild type to a degree but could be easily masked by high rates of the enzymic process. PMID:16667445

  6. Isolation of a novel mutant from Bacillus subtilis natto.

    PubMed

    Yoshida, Kazuo

    2006-01-01

    For the construction of strains with full probiotics function in intestines, deoxycholate resistant mutants were isolated from Bacillus subtilis natto. The partial characterization of the mutants was carried out and described. PMID:17150923

  7. Genes and signaling pathways involved in memory enhancement in mutant mice

    PubMed Central

    2014-01-01

    Mutant mice have been used successfully as a tool for investigating the mechanisms of memory at multiple levels, from genes to behavior. In most cases, manipulating a gene expressed in the brain impairs cognitive functions such as memory and their underlying cellular mechanisms, including synaptic plasticity. However, a remarkable number of mutations have been shown to enhance memory in mice. Understanding how to improve a system provides valuable insights into how the system works under normal conditions, because this involves understanding what the crucial components are. Therefore, more can be learned about the basic mechanisms of memory by studying mutant mice with enhanced memory. This review will summarize the genes and signaling pathways that are altered in the mutants with enhanced memory, as well as their roles in synaptic plasticity. Finally, I will discuss how knowledge of memory-enhancing mechanisms could be used to develop treatments for cognitive disorders associated with impaired plasticity. PMID:24894914

  8. Enhanced Lipid Productivity and Photosynthesis Efficiency in a Desmodesmus sp. Mutant Induced by Heavy Carbon Ions

    PubMed Central

    Hu, Guangrong; Fan, Yong; Zhang, Lei; Yuan, Cheng; Wang, Jufang; Li, Wenjian; Hu, Qiang; Li, Fuli

    2013-01-01

    The unicellular green microalga Desmodesmus sp. S1 can produce more than 50% total lipid of cell dry weight under high light and nitrogen-limitation conditions. After irradiation by heavy 12C6+ ion beam of 10, 30, 60, 90 or 120 Gy, followed by screening of resulting mutants on 24-well microplates, more than 500 mutants were obtained. One of those, named D90G-19, exhibited lipid productivity of 0.298 g L?1?d?1, 20.6% higher than wild type, likely owing to an improved maximum quantum efficiency (Fv/Fm) of photosynthesis under stress. This work demonstrated that heavy-ion irradiation combined with high-throughput screening is an effective means for trait improvement. The resulting mutant D90G-19 may be used for enhanced lipid production. PMID:23593286

  9. USE OF 8-AZAGUANINE FOR THE ISOLATION OF AUXOTROPHIC MUTANTS OF BACILLUS MEGATERIUM

    PubMed Central

    Wachsman, J. T.; Mangalo, R.

    1962-01-01

    Wachsman, J. T. (University of Illinois, Urbana) and R. Mangalo. Use of 8-azaguanine for the isolation of auxotrophic mutants of Bacillus megaterium. J. Bacteriol. 83:35–37. 1962.—8-Azaguanine is bactericidal for Bacillus megaterium strain KM, primarily under conditions where growth is possible. This analogue has been used to enrich for auxotrophic mutants in ultraviolet-irradiated populations. The survivors were found to contain from 1.6 to 33.0% amino acid auxotrophs and from 19 to 29% pyrimidine nucleoside auxotrophs. Since many different biological systems are sensitive to 8-azaguanine, the use of this analogue to enrich for auxotrophic mutants may have a more general application than techniques currently employed. PMID:14004193

  10. The role of cationic amino acid residues in the lethal activity of stonustoxin from stonefish (Synanceja horrida) venom.

    PubMed

    Khoo, H E; Chen, D; Yuen, R

    1998-03-01

    Stonustoxin (SNTX) is a two subunit pore-forming cytolytic protein purified from the venom of the stonefish (Synanceja horrida). SNTX also possesses lethal activity. Since cationic residues contribute significantly to the cytolytic activity of several pore-forming toxins, we examined the role of lysine and arginine residues in the lethal activity of SNTX. SNTX lost its lethal activity when the positively-charged side chains of lysine residues were converted to negatively-charged side chains upon succinylation. When the arginine residues were modified using 2,3-butanedione, SNTX also lost its lethal activity. However, the domains for cytolytic and lethal activity may not necessarily be the same. PMID:9556226

  11. bop gene cluster expression in bacteriorhodopsin-overproducing mutants of Halobacterium halobium.

    PubMed Central

    Shand, R F; Betlach, M C

    1994-01-01

    mRNA levels from the bop (bacterio-opsin), brp (bacterio-opsin-related protein), and bat (bacterio-opsin activator) genes in wild-type Halobacterium halobium and two bacteriorhodopsin-overproducing mutants (ET1001 and II-7) were quantitated under conditions in which oxygen levels were steadily depleted and then cultures were either kept in the dark or exposed to light. All three strains showed similar responses to depleted oxygen tensions and the lack of light: bop gene cluster transcript levels first increased in response to steadily declining oxygen, and once oxygen was depleted, transcript levels decreased and became undetectable within 20 to 40 h. In contrast, each strain responded differently to conditions of depleted oxygen and the presence of light. In the wild-type strain, bop gene cluster transcript levels increased 2.4- to 9.2-fold above the highest levels obtained in the dark. In mutant ET1001, bop gene cluster transcript levels did not increase above the highest levels obtained in the dark. In mutant II-7, bop and brp transcript levels did not increase above the highest levels obtained in the dark, but bat transcript levels increased approximately 5.7-fold. This differing response to identical physiological conditions indicates that the mutations resulting in the bacteriorhodopsin-overproducing phenotype in these two mutants are different. PMID:8132460

  12. Synthetic-lethal interactions identify two novel genes, SLA1 and SLA2, that control membrane cytoskeleton assembly in Saccharomyces cerevisiae

    PubMed Central

    1993-01-01

    Abplp is a yeast cortical actin-binding protein that contains an SH3 domain similar to those found in signal transduction proteins that function at the membrane/cytoskeleton interface. Although no detectable phenotypes are associated with a disruption allele of ABP1, mutations that create a requirement for this protein have now been isolated in the previously identified gene SAC6 and in two new genes, SLA1 and SLA2. The SAC6 gene encodes yeast fimbrin, an actin filament-bundling protein. Null mutations in SLA1 and SLA2 cause temperature-sensitive growth defects. Sla1p contains three SH3 domains and is essential for the proper formation of the cortical actin cytoskeleton. The COOH terminus of Sla2p contains a 200 amino acid region with homology to the COOH terminus of talin, a membrane cytoskeletal protein which is a component of fibroblast focal adhesions. Sla2p is required for cellular morphogenesis and polarization of the cortical cytoskeleton. In addition, synthetic-lethal interactions were observed for double- mutants containing null alleles of SLA2 and SAC6. In total, the mutant phenotypes, sequences, and genetic interactions indicate that we have identified novel proteins that cooperate to control the dynamic cytoskeletal rearrangements that are required for the development of cell polarity in budding yeast. PMID:8335689

  13. Cost of reproduction. Changes in metabolism and endosulfan lethality caused by reproductive behavior in Hyalella curvispina (Crustacea: Amphipoda).

    PubMed

    Negro, C L; Castiglioni, M; Senkman, L E; Loteste, A; Collins, P

    2013-04-01

    Biocides are periodically applied in agricultural activities, reaching aquatic systems and acting upon the biota. Amphipods are widely used in toxicity tests because of their sensitivity to a wide range of pollutants. In this work, we report the differential lethality of a widely used pesticide, endosulfan, on the amphipod Hyalella curvispina at two life stages and in three different adult groups, males and females separated by sex and both sexes grouped together. In addition, oxygen consumption of adult groups was determined as a way to estimate the role of behavioral activities and exposure to endosulfan in metabolism shifts. There were no differences between the LC(50) of juveniles and the adults when they were separated by sex (p>0.05). Nevertheless, the LC(50) of adults without sexual differentiation was significantly lower than the LC(50) of juveniles and adults separated by sex (p<0.05). The oxygen consumption rate was higher when adults were grouped without sexual differentiation in the control group. The exposure to low concentrations of endosulfan causes an increase in oxygen consumption in all the treatments. The sexual behavior increased the metabolism and the sensitivity to endosulfan. In future evaluations, adults grouped without sexual differentiation, which were the most sensitive group, should be included in order to mimic the environmental conditions. Using only juveniles or adults separated by sex in toxicity tests may inaccurately estimate the lethality of biocides, especially in species with constant reproductive activities. PMID:23352127

  14. Anther developmental defects in Arabidopsis thaliana male-sterile mutants

    Microsoft Academic Search

    Paul M. Sanders; Anhthu Q. Bui; Koen Weterings; Katherine N. McIntire; Yung-Chao Hsu; Pei Yun Lee; Mai Thy Truong; T. P. Beals; R. B. Goldberg

    1999-01-01

    We identified Arabidopsis thaliana sterility mutants by screening T-DNA and EMS-mutagenized lines and characterized several male-sterile mutants with defects\\u000a specific for different anther processes. Approximately 44 and 855 sterile mutants were uncovered from the T-DNA and EMS screens,\\u000a respectively. Several mutants were studied in detail with defects that included the establishment of anther morphology, microspore\\u000a production, pollen differentiation, and anther

  15. Identification of plant cell wall mutants by means of a forward chemical genetic approach using hydrolases

    PubMed Central

    Gille, Sascha; Hänsel, Ulrike; Ziemann, Mark; Pauly, Markus

    2009-01-01

    A previously undescribed forward chemical genetic screen using hydrolases affecting the extracellular matrix is introduced. The developed screen takes advantage of the power of chemical genetics and combines it with the known substrate specificity of glycosylhydrolases, resulting in the selection of conditional mutants that exhibit structural defects in their extracellular matrix. Identification of the responsible genetic locus in those mutants significantly extends our knowledge of genes involved in the biosynthesis, metabolism, signaling, and functionality of components of the extracellular matrix. The method is exemplified by a screen of mutagenized Arabidopsis plants subjected to growth in liquid culture in the presence of a xyloglucanase, an enzyme acting on the major cross-linking glycan found in the extracellular matrix of this plant. Using this hydrolase-based screen, dozens of plant cell wall mutants (xeg mutants) were identified, leading to the identification of 23 genetic loci that affect plant cell walls. One of the identified loci is XEG113, encoding a family 77 glycosyltransferase (GT77). Detailed analysis of the wall of this mutant indicated that its extensins, structural glyocoproteins present in walls, are underarabinosylated. Xeg-113 plants exhibit more elongated hypocotyls than WT, providing genetic evidence that plant O-glycosylation—more specifically, extensin arabinosylation—is important for cell elongation. PMID:19667208

  16. Pyruvate carboxylase from Rhizobium etli: mutant characterization, nucleotide sequence, and physiological role.

    PubMed Central

    Dunn, M F; Encarnación, S; Araíza, G; Vargas, M C; Dávalos, A; Peralta, H; Mora, Y; Mora, J

    1996-01-01

    Pyruvate carboxylase (PYC), a biotin-dependent enzyme which catalyzes the conversion of pyruvate to oxaloacetate, was hypothesized to play an important anaplerotic role in the growth of Rhizobium etli during serial subcultivation in minimal media containing succinate (S. Encarnación, M. Dunn, K. Willms, and J. Mora, J. Bacteriol. 177:3058-3066, 1995). R. etli and R. tropici pyc::Tn5-mob mutants were selected for their inability to grow in minimal medium with pyruvate as a sole carbon source. During serial subcultivation in minimal medium containing 30 mM succinate, the R. etli parent and pyc mutant strains exhibited similar decreases in growth rate with each subculture. Supplementation of the medium with biotin prevented the growth decrease of the parent but not the mutant strain, indicating that PYC was necessary for the growth of R. etli under these conditions. The R. tropici pyc mutant grew normally in subcultures regardless of biotin supplementation. The symbiotic phenotypes of the pyc mutants from both species were similar to those of the parent strains. The R. etli pyc was cloned, sequenced, and found to encode a 126-kDa protein of 1,154 amino acids. The deduced amino acid sequence is highly homologous to other PYC sequences, and the catalytic domains involved in carboxylation, pyruvate binding, and biotinylation are conserved. The sequence and biochemical data show that the R. etli PYC is a member of the alpha4, homotetrameric, acetyl coenzyme A-activated class of PYCs. PMID:8830693

  17. TSpred: a web server for the rational design of temperature-sensitive mutants.

    PubMed

    Tan, Kuan Pern; Khare, Shruti; Varadarajan, Raghavan; Madhusudhan, Mallur Srivatsan

    2014-07-01

    Temperature sensitive (Ts) mutants of proteins provide experimentalists with a powerful and reversible way of conditionally expressing genes. The technique has been widely used in determining the role of gene and gene products in several cellular processes. Traditionally, Ts mutants are generated by random mutagenesis and then selected though laborious large-scale screening. Our web server, TSpred (http://mspc.bii.a-star.edu.sg/TSpred/), now enables users to rationally design Ts mutants for their proteins of interest. TSpred uses hydrophobicity and hydrophobic moment, deduced from primary sequence and residue depth, inferred from 3D structures to predict/identify buried hydrophobic residues. Mutating these residues leads to the creation of Ts mutants. Our method has been experimentally validated in 36 positions in six different proteins. It is an attractive proposition for Ts mutant engineering as it proposes a small number of mutations and with high precision. The accompanying web server is simple and intuitive to use and can handle proteins and protein complexes of different sizes. PMID:24782523

  18. Properties of Bacillus cereus temperature-sensitive mutants altered in spore coat formation.

    PubMed Central

    Stelma, G N; Aronson, A I; Fitz-James, P

    1978-01-01

    Three conditional Bacillus cereus mutants altered in the assembly or formation of spore coat layers were analyzed. They all grew as well as the wild type in an enriched or minimal medium but produced lysozyme and octanol-sensitive spores at the nonpermissive temperature (35 to 38 degrees C). The spores also germinated slowly when produced at 35 degrees C. Temperature-shift experiments indicated that the defective protein or regulatory signal is expressed at the time of formation of the outer spore coat layers. Revertants regained all wild-type spore properties at frequencies consistent with initial point mutations. Spore coat defects were evident in thin sections and freeze-etch micrographs of mutant spores produced at 35 degrees C. In addition, one mutant contained an extra surface deposit, perhaps unprocessed spore coat precursor protein. A prevalent band of about 65,000 daltons (the same size as the presumptive precursor) was present in spore coat extracts of this mutant and may be incorrectly processed to mature spore coat polypeptides. Another class of mutants was defective in the late uptake of half-cystine residues into spore coats. Such a defect could lead to improper formation of the outer spore coat layers. Images PMID:96097

  19. The responses of trichome mutants to enhanced ultraviolet-B radiation in Arabidopsis thaliana.

    PubMed

    Yan, An; Pan, Jianbin; An, Lizhe; Gan, Yinbo; Feng, Huyuan

    2012-08-01

    To gain a better understanding of the protective function of the trichome in Arabidopsis against UV-B radiation, we performed a study using several Arabidopsis trichome mutants (gl1, gis, gis2, zfp8, try82, and gl3), overexpressing trichome positive regulator lines (35S:GIS and 35S:GIS2), and wild-types (WT) under simulated enhanced UV-B radiation conditions. The flowering time, height, diameter of rosette, leaf size, trichome density, and expression levels of GL3 gene were measured. Significant decreases in height, diameter of rosette, leaf size, and a notable delay in flowering time were observed in all mutants and wild-types after exposure to UV-B. Moreover, the trichome density showed a significant increase, suggesting a clear induction of trichome formation by UV-B. Comparing the mutants and WT, we found that the mutants that had more trichomes showed a lower sensitivity to UV-B than the WT, whereas the mutants that had fewer trichomes were more sensitive to UV-B. These results indicated that the trichome plays a key shielding role against UV-B radiation. qRT-PCR analysis indicated that UV-B radiation induced expression of GL3 and an increase in GL3 transcript level correlated with the increase in trichome density and, suggesting a possible role of GL3 by integrating the environmental signal to control trichome initiation. PMID:22647943

  20. Generation of an isogenic collection of yeast actin mutants and identification of three interrelated phenotypes.

    PubMed

    Whitacre, J; Davis, D; Toenjes, K; Brower, S; Adams, A

    2001-02-01

    A large collection of yeast actin mutations has been previously isolated and used in numerous studies of actin cytoskeletal function. However, the various mutations have been in congenic, rather than isogenic, backgrounds, making it difficult to compare the subtle phenotypes that are characteristic of these mutants. We have therefore placed 27 mutations in an isogenic background. We used a subset of these mutants to compare the degree to which different actin alleles are defective in sporulation, endocytosis, and growth on NaCl-containing media. We found that the three phenotypes are highly correlated. The correlations are specific and not merely a reflection of general growth defects, because the phenotypes are not correlated with growth rates under normal conditions. Significantly, those actin mutants exhibiting the most severe phenotypes in all three processes have altered residues that cluster to a small region of the actin crystal structure previously defined as the fimbrin (Sac6p)-binding site. We examined the relationship between endocytosis and growth on salt and found that shifting wild-type or actin mutant cells to high salt reduces the rate of alpha-factor internalization. These results suggest that actin mutants may be unable to grow on salt because of additive endocytic defects (due to mutation and salt). PMID:11156976

  1. Generation of an isogenic collection of yeast actin mutants and identification of three interrelated phenotypes.

    PubMed Central

    Whitacre, J; Davis, D; Toenjes, K; Brower, S; Adams, A

    2001-01-01

    A large collection of yeast actin mutations has been previously isolated and used in numerous studies of actin cytoskeletal function. However, the various mutations have been in congenic, rather than isogenic, backgrounds, making it difficult to compare the subtle phenotypes that are characteristic of these mutants. We have therefore placed 27 mutations in an isogenic background. We used a subset of these mutants to compare the degree to which different actin alleles are defective in sporulation, endocytosis, and growth on NaCl-containing media. We found that the three phenotypes are highly correlated. The correlations are specific and not merely a reflection of general growth defects, because the phenotypes are not correlated with growth rates under normal conditions. Significantly, those actin mutants exhibiting the most severe phenotypes in all three processes have altered residues that cluster to a small region of the actin crystal structure previously defined as the fimbrin (Sac6p)-binding site. We examined the relationship between endocytosis and growth on salt and found that shifting wild-type or actin mutant cells to high salt reduces the rate of alpha-factor internalization. These results suggest that actin mutants may be unable to grow on salt because of additive endocytic defects (due to mutation and salt). PMID:11156976

  2. The photosensitive phs1 mutant is impaired in the riboflavin biogenesis pathway.

    PubMed

    Ouyang, Min; Ma, Jinfang; Zou, Meijuan; Guo, Jinkui; Wang, Liyuan; Lu, Congming; Zhang, Lixin

    2010-11-15

    A photosensitive (phs1) mutant of Arabidopsis thaliana was isolated and characterized. The PHS1 gene was cloned using a map-based approach. The gene was found to encode a protein containing a deaminase-reductase domain that is involved in the riboflavin pathway. The phenotype and growth of the phs1 mutant were comparable to that of the wild-type when the plants were grown under low light conditions. When the light intensity was increased, the mutant was characterized by stunted growth and bleached leaves as well as a decrease in FNR activity. The NADPH levels declined, whereas the NADP(+) levels increased, leading to a decrease in the NADPH/NADP(+) ratio. The mutant suffered from severe photooxidative damage with an increase in antioxidant enzyme activity and a drastic reduction in the levels of chlorophyll and photosynthetic proteins. Supplementing the mutant with exogenous FAD rescued the photosensitive phenotype, even under increasing light intensity. The riboflavin pathway therefore plays an important role in protecting plants from photooxidative damage. PMID:20580123

  3. Activity of the response regulator CiaR in mutants of Streptococcus pneumoniae R6 altered in acetyl phosphate production.

    PubMed

    Marx, Patrick; Meiers, Marina; Brückner, Reinhold

    2014-01-01

    The two-component regulatory system (TCS) CiaRH of Streptococcus pneumoniae is implicated in competence, ß-lactam resistance, maintenance of cell integrity, bacteriocin production, host colonization, and virulence. Depending on the growth conditions, CiaR can be highly active in the absence of its cognate kinase CiaH, although phosphorylation of CiaR is required for DNA binding and gene regulation. To test the possibility that acetyl phosphate (AcP) could be the alternative phosphodonor, genes involved in pyruvate metabolism were disrupted to alter cellular levels of acetyl phosphate. Inactivating the genes of pyruvate oxidase SpxB, phosphotransacetylase Pta, and acetate kinase AckA, resulted in very low AcP levels and in strongly reduced CiaR-mediated gene expression in CiaH-deficient strains. Therefore, alternative phosphorylation of CiaR appears to proceed via AcP. The AcP effect on CiaR is not detected in strains with CiaH. Attempts to obtain elevated AcP by preventing its degradation by acetate kinase AckA, were not successful in CiaH-deficient strains with a functional SpxB, the most important enzyme for AcP production in S. pneumoniae. The ciaH-spxB-ackA mutant producing intermediate amounts of AcP could be constructed and showed a promoter activation, which was much higher than expected. Since activation was dependent on AcP, it can apparently be used more efficiently for CiaR phosphorylation in the absence of AckA. Therefore, high AcP levels in the absence of CiaH and AckA may cause extreme overexpression of the CiaR regulon leading to synthetic lethality. AckA is also involved in a regulatory response, which is mediated by CiaH. Addition of acetate to the growth medium switch CiaH from kinase to phosphatase. This switch is lost in the absence of AckA indicating metabolism of acetate is required, which starts with the production of AcP by AckA. Therefore, AckA plays a special regulatory role in the control of the CiaRH TCS. PMID:25642214

  4. Parallel profiling of fission yeast deletion mutants for proliferation and for lifespan during long-term quiescence.

    PubMed

    Sideri, Theodora; Rallis, Charalampos; Bitton, Danny A; Lages, Bruno M; Suo, Fang; Rodríguez-López, María; Du, Li-Lin; Bähler, Jürg

    2014-01-01

    Genetic factors underlying aging are remarkably conserved from yeast to human. The fission yeast Schizosaccharomyces pombe is an emerging genetic model to analyze cellular aging. Chronological lifespan (CLS) has been studied in stationary-phase yeast cells depleted for glucose, which only survive for a few days. Here, we analyzed CLS in quiescent S. pombe cells deprived of nitrogen, which arrest in a differentiated, G0-like state and survive for more than 2 months. We applied parallel mutant phenotyping by barcode sequencing (Bar-seq) to assay pooled haploid deletion mutants as they aged together during long-term quiescence. As expected, mutants with defects in autophagy or quiescence were under-represented or not detected. Lifespan scores could be calculated for 1199 mutants. We focus the discussion on the 48 most long-lived mutants, including both known aging genes in other model systems and genes not previously implicated in aging. Genes encoding membrane proteins were particularly prominent as pro-aging factors. We independently verified the extended CLS in individual assays for 30 selected mutants, showing the efficacy of the screen. We also applied Bar-seq to profile all pooled deletion mutants for proliferation under a standard growth condition. Unlike for stationary-phase cells, no inverse correlation between growth and CLS of quiescent cells was evident. These screens provide a rich resource for further studies, and they suggest that the quiescence model can provide unique, complementary insights into cellular aging. PMID:25452419

  5. Notch1 loss of heterozygosity causes vascular tumors and lethal hemorrhage in mice

    PubMed Central

    Liu, Zhenyi; Turkoz, Ahu; Jackson, Erin N.; Corbo, Joseph C.; Engelbach, John A.; Garbow, Joel R.; Piwnica-Worms, David R.; Kopan, Raphael

    2011-01-01

    The role of the Notch signaling pathway in tumor development is complex, with Notch1 functioning either as an oncogene or as a tumor suppressor in a context-dependent manner. To further define the role of Notch1 in tumor development, we systematically surveyed for tumor suppressor activity of Notch1 in vivo. We combined the previously described Notch1 intramembrane proteolysis–Cre (Nip1::Cre) allele with a floxed Notch1 allele to create a mouse model for sporadic, low-frequency loss of Notch1 heterozygosity. Through this approach, we determined the cell types most affected by Notch1 loss. We report that the loss of Notch1 caused widespread vascular tumors and organism lethality secondary to massive hemorrhage. These findings reflected a cell-autonomous role for Notch1 in suppressing neoplasia in the vascular system and provide a model by which to explore the mechanism of neoplastic transformation of endothelial cells. Importantly, these results raise concerns regarding the safety of chronic application of drugs targeting the Notch pathway, specifically those targeting Notch1, because of mechanism-based toxicity in the endothelium. Our strategy also can be broadly applied to induce sporadic in vivo loss of heterozygosity of any conditional alleles in progenitors that experience Notch1 activation. PMID:21266774

  6. Ryanodine receptor as a new therapeutic target of heart failure and lethal arrhythmia.

    PubMed

    Yano, Masafumi

    2008-04-01

    Abnormal intracellular Ca(2+) handling by the sarcoplasmic reticulum (SR) is a critical factor in the development of heart failure (HF). Not only decreased Ca(2+) uptake, but also uncoordinated Ca(2+) release plays a significant role in contractile and relaxation dysfunction. Spontaneous Ca(2+) release through ryanodine receptor (RyR) 2, a huge tetrameric protein, during diastole leads to a decrease in the SR Ca(2+) content, and also triggers delayed after depolarization that is a substrate for lethal arrhythmia. Several disease-linked mutations of RyR have been reported in patients with catecholaminergic polymorphic ventricular tachycardia (CPVT) or arrhythmogenic right ventricular cardiomyopathy type 2 (ARVC2). The unique distribution of these mutation sites has lead to the concept that an interaction among the putative regulatory domains within RyR may play a key role in regulating channel opening, and that there seems to be a common abnormality in the channel disorder of HF and CPVT/ARVC2. Recent knowledge gained from pathological conditions may lead to the development of a new therapeutic strategy for the treatment of HF or cardiac arrhythmia. PMID:18362417

  7. Lethal Thermal Impact at Periphery of Pyroclastic Surges: Evidences at Pompeii

    PubMed Central

    Mastrolorenzo, Giuseppe; Petrone, Pierpaolo; Pappalardo, Lucia; Guarino, Fabio M.

    2010-01-01

    Background The evaluation of mortality of pyroclastic surges and flows (PDCs) produced by explosive eruptions is a major goal in risk assessment and mitigation, particularly in distal reaches of flows that are often heavily urbanized. Pompeii and the nearby archaeological sites preserve the most complete set of evidence of the 79 AD catastrophic eruption recording its effects on structures and people. Methodology/Principal Findings Here we investigate the causes of mortality in PDCs at Pompeii and surroundings on the bases of a multidisciplinary volcanological and bio-anthropological study. Field and laboratory study of the eruption products and victims merged with numerical simulations and experiments indicate that heat was the main cause of death of people, heretofore supposed to have died by ash suffocation. Our results show that exposure to at least 250°C hot surges at a distance of 10 kilometres from the vent was sufficient to cause instant death, even if people were sheltered within buildings. Despite the fact that impact force and exposure time to dusty gas declined toward PDCs periphery up to the survival conditions, lethal temperatures were maintained up to the PDCs extreme depositional limits. Conclusions/Significance This evidence indicates that the risk in flow marginal zones could be underestimated by simply assuming that very thin distal deposits, resulting from PDCs with poor total particle load, correspond to negligible effects. Therefore our findings are essential for hazard plans development and for actions aimed to risk mitigation at Vesuvius and other explosive volcanoes. PMID:20559555

  8. Effects of DDE on experimentally poisoned free-tailed bats (Tadarida brasiliensis): lethal brain concentrations.

    PubMed

    Clark, D R; Kroll, J C

    1977-12-01

    Adult female free-tailed bats (Tadarida brasiliensis) were collected at Bracken Cave, Texas, and shipped to the Patuxent Wildlife Research Center. Treated mealworms (Tenebrio molitor) containing 107 ppm DDE were fed to 17 bats; five other bats were fed untreated mealworms. After 40 days on dosage, during which one dosed bat was killed accidentally, four dosed bats were frozen and the remaining 17 were starved to death. The objective was to elevate brain levels of DDE to lethality and measure these concentrations. After the feeding period, dosed bats weighed less than controls. After starvation, the body condition of dosed bats was poorer than that of controls even though there was no difference in the amounts of carcass fat. During starvation, dosed bats lost weight faster than controls. Also, four dosed bats exhibited the prolonged tremoring that characterizes DDE poisoning. DDE increased in brains of starving bats as fat was metabolized. The estimated mean brain concentration of DDE diagnostic of death was 519 ppm with a range of 458-564 ppm. These values resemble diagnostic levels known for two species of passerine birds, but they exceed published levels for two free-tailed bats from Carlsbad Caverns, New Mexico. PMID:599587

  9. Anthrax lethal toxin suppresses high glucose induced VEGF over secretion through a post-translational mechanism

    PubMed Central

    Zhang, Wei-Wei; Wang, Xin; Xie, Ping; Yuan, Song-Tao; Liu, Qing-Huai

    2015-01-01

    AIM To prove anthrax lethal toxin (LeTx) blocks the mitogen activated protein kinases (MAPKs) activation by degrading the MAPK/ERK kinases (MEKs) to suppress vascular endothelial growth factor (VEGF) secretion. METHODS Human adult retinal pigmented epithelium (ARPE) cells were cultured and treated with normal glucose, high glucose or high glucose with LeTx for additional 24, 48 or 72h for viable cell count. Total RNA from the ARPE was isolated for reverse transcription polymerase chain reaction (RT-PCR). The conditioned medium of ARPE cells treated in different group for 48h was filtered and diluted to detect the concentration of VEGF by enzyme-linked immunosorbant assays. Evaluate the role of MEK/MAPK pathway in the secretion of VEGF by immunoblotting. RESULTS In this study, we proved high glucose induced activation of the MAPK extracellular signal-regulated kinase (ERK1/2) and p38 in the ARPE cell line was blocked by anthrax LeTx. LeTx also inhibited high glucose induced ARPE cell over proliferation. CONCLUSION LeTx suppressed high glucose induced VEGF over secretion in the ARPE cells, mainly through a post-translational mechanism. PMID:26085990

  10. Effects of DDE on experimentally poisoned free-tailed bats (Tadarida brasiliensis): Lethal brain concentrations

    USGS Publications Warehouse

    Clark, D.R., Jr.; Kroll, J.C.

    1977-01-01

    Adult female free-tailed bats (Tadarida brasiliensis) were collected at Bracken Cave, Texas, and shipped to the Patuxent Wildlife Research Center. Treated mealworms (Tenebrio molitor) containing 107 ppm DDE were fed to 17 bats; five other bats were fed untreated mealworms. After 40 days on dosage, during which one dosed bat was killed accidentally, four dosed bats were frozen and the remaining 17 were starved to death. The objective was to elevate brain levels of DDE to lethality and measure these concentrations. After the feeding period, dosed bats weighed less than controls. After starvation, the body condition of dosed bats was poorer than that of controls even though there was no difference in the amounts of carcass fat. During starvation, dosed bats lost weight faster than controls. Also, four dosed bats exhibited the prolonged tremoring that characterizes DDE poisoning. DDE increased in brains of starving bats as fat was metabolized. The estimated mean brain concentration of DDE diagnostic of death was 519 ppm with a range of 458-564 ppm. These values resemble diagnostic levels known for two species of passerine birds, but they exceed published levels for two free-tailed bats from Carlsbad Caverns, New Mexico.

  11. Article de Synthse MUTANTS AVIRULENTS DU VIRUS RABIQUE

    E-print Network

    Boyer, Edmond

    OF THE GLYCOPROTEIN. -- Using antiglycoprotein neutralizing monoclonal antibodies, avirulent mutants of rabies virusArticle de Synthèse MUTANTS AVIRULENTS DU VIRUS RABIQUE: ALTÉRATION DU SITE III DE LA GLYCOPROTÉINE, 94704 Maisons-Alfort Cedex, France Summary AVIRULENT MUTANTS OF RABIES VIRUS: CHANGE IN THE SITE III

  12. Releasing the Block: Setting Differentiation Free with Mutant IDH Inhibitors

    PubMed Central

    Pirozzi, Christopher J.; Reitman, Zachary J.; Yan, Hai

    2015-01-01

    Hotspot mutations in IDH1 and IDH2 cause a differentiation block that can promote tumorigenesis. Two recent papers reported that small molecules targeting mutant IDH1 or mutant IDH2 release this differentiation block and/or impede tumor growth, providing a proof-of-concept that mutant IDHs are therapeutically targetable and that their effects are reversible. PMID:23680144

  13. RISC Assembly Defects in the Drosophila RNAi Mutant armitage

    Microsoft Academic Search

    Yukihide Tomari; Tingting Du; Benjamin Haley; Dianne S. Schwarz; Ryan Bennett; Heather A. Cook; Birgit S. Koppetsch; William E. Theurkauf; Phillip D. Zamore

    2004-01-01

    The putative RNA helicase, Armitage (Armi), is required to repress oskar translation in Drosophila oocytes; armi mutant females are sterile and armi mutations disrupt anteroposterior and dorsoventral patterning. Here, we show that armi is required for RNAi. armi mutant male germ cells fail to silence Stellate, a gene regulated endogenously by RNAi, and lysates from armi mutant ovaries are defective

  14. REGISTRRATION OF AN INDUCED SEMIDWARF MUTANT OF RICE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A mutant for semidwarfism was induced in the long grain Drew. The mutant, designated DR1, was 27 cm shorter than its parent and 7330 compared to 8060 kg/ha for its parent. Grain dimensions and amylose content were similar to the parent. The new recessive mutant was nonallic to sd1, the worldwide ...

  15. Generation and evaluation of virulence attenuated mutants of Edwardsiella tarda as vaccine candidates to combat edwardsiellosis in flounder (Paralichthys olivaceus).

    PubMed

    Li, Jie; Mo, Zhaolan; Li, Guiyang; Xiao, Peng; Huang, Jie

    2015-03-01

    Edwardsiella tarda is an intracellular pathogen that causes edwardsiellosis in fish. The development of a live attenuated vaccine may be an effective approach for preventing this disease in fish. In this study, we introduced deletions of esrB, esaC, evpH, rpoS, and purA into the E. tarda LSE40?aroA strain, thereby generating five double-gene mutants (?aroA?esrB, ?aroA?esaC, ?aroA?rpoS, ?aroA?evpH, and ?aroA?purA) and two triple-gene mutants (?aroA?esrB?evpH and ?aroA?esaC?evpH). When blue gourami (Trichogaster trichopterus) was used as a fish model for the primary screening and evaluation of the vaccine candidates, all mutants were attenuated significantly by more than 2 to 3 logs in terms of the 50% lethal dose (LD(50)). Five double-gene mutants yielded relative percentage survival (RPS) rates of 26.1-82.6% after challenge with wild-type E. tarda. The ?aroA?esrB mutant that conferred the highest RPS (82.6%) in blue gourami was also evaluated in flounder (Paralichthys olivaceus). After vaccination via intramuscular (i.m.) injection or immersion, this mutant could persist in the flounder for 14-35 days and it induced higher serum antibody titers than the control fish (P < 0.01). Flounder vaccinated via i.m. injection at doses of 10(3)-10(7) CFU/fish had RPS rates of 14.3-66.7% after i.m. challenge with 10(4) CFU/fish using wild-type E. tarda. Flounder vaccinated via immersion at a dose of 10(7) CFU/ml exhibited 100% RPS against immersion challenge with 10(7) CFU/ml using wild-type E. tarda. These results indicate that the ?aroA?esrB mutant could be used as an effective live vaccine to combat edwardsiellosis in flounder. PMID:25541077

  16. 40 CFR 798.5275 - Sex-linked recessive lethal test in drosophila melanogaster.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...approximately one-fifth of the entire haploid genome. (b) Definitions. (1) Lethal mutation is a change in the genome which, when expressed, causes death...Recessive mutation is a change in the genome which is expressed in the...

  17. 40 CFR 798.5275 - Sex-linked recessive lethal test in drosophila melanogaster.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...approximately one-fifth of the entire haploid genome. (b) Definitions. (1) Lethal mutation is a change in the genome which, when expressed, causes death...Recessive mutation is a change in the genome which is expressed in the...

  18. Lethal aggression in mobile forager bands and implications for the origins of war.

    PubMed

    Fry, Douglas P; Söderberg, Patrik

    2013-07-19

    It has been argued that warfare evolved as a component of early human behavior within foraging band societies. We investigated lethal aggression in a sample of 21 mobile forager band societies (MFBS) derived systematically from the standard cross-cultural sample. We hypothesized, on the basis of mobile forager ethnography, that most lethal events would stem from personal disputes rather than coalitionary aggression against other groups (war). More than half of the lethal aggression events were perpetrated by lone individuals, and almost two-thirds resulted from accidents, interfamilial disputes, within-group executions, or interpersonal motives such as competition over a particular woman. Overall, the findings suggest that most incidents of lethal aggression among MFBS may be classified as homicides, a few others as feuds, and a minority as war. PMID:23869015

  19. ORIGINAL PAPER Evaluating the impact of non-lethal DNA sampling on two

    E-print Network

    Landis, Doug

    ORIGINAL PAPER Evaluating the impact of non-lethal DNA sampling on two butterflies, Vanessa cardui of Vanessa cardui and Satyrodes eurydice. Based on these studies we were successful in obtaining a permit

  20. A model of anthrax toxin lethal factor bound to protective antigen

    E-print Network

    Baker, David

    translocation in an N- to C-terminal direction. computation docking electrostatic Bacillus anthracis), and lethal factor (LF), that are collectively referred to as anthrax toxin (1). After its proteolytic