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1

The use of biological methods to determine the microbiological activity of soils under cultivation  

Microsoft Academic Search

In Ap horizons of typical arable soils under cereals in Northwest Germany, biological activity was estimated by measuring microbial activity. Twelve soils on local farms and six soils on a research farm were analysed. Microbial biomass, dehydrogenase activity, and alkaline phosphatase activity were compared with the biological availability of P, an index describing the relationship among several P fractions that

L. Beyer; C. Wachendorf; F. M. Balzer; U. R. Balzer-Graf

1992-01-01

2

SOIL BIOLOGY AND ECOLOGY  

EPA Science Inventory

The term "Soil Biology", the study of organism groups living in soil, (plants, lichens, algae, moss, bacteria, fungi, protozoa, nematodes, and arthropods), predates "Soil Ecology", the study of interactions between soil organisms as mediated by the soil physical environment. oil ...

3

Effects of gentle remediation technologies on soil biological and biochemical activities - a review.  

NASA Astrophysics Data System (ADS)

Remediation technologies for contaminated sites are generally designed to reduce risks for human health, groundwater or plant quality. While some drastic remediation measures such as soil excavation, thermal treatment or soil washing eliminate or strongly reduce soil life, in-situ treatments involving plants or immobilizing additives may also restore soil functionality by establishing or promoting a well structured and active community of soil organisms. Biological parameters that are sensitive to contaminants and other pedo-environmental conditions and which contribute to biogeochemical nutrient cycles, can be used as synthetic indicators of the progress and also the efficiency of given remediation approaches. Data from long-term studies on re-vegetated mine spoils show that biological and biochemical activity is enhanced with increasing plant density and diversity. Among the soil amendments, most measures that introduce organic matter or alkalinity to the contaminated soils also improve microbial or faunal parameters. Only few amendments, such as phosphates and chelators have deleterious effects on soil biota. In this review, soil microbial biomass and the activity of the enzymes phosphatase and arylsulphatase are identified as suitable and sensitive biological indicators for soil health. The results and future research needs are are summarized.

Marschner, B.; Haag, R.; Renella, G.

2009-04-01

4

THE IMPACT OF SULFONYLUREA AND NON-SELECTIVE HERBICIDES ON BIOLOGICAL ACTIVITY OF SANDY SOILS  

Microsoft Academic Search

The evaluation of soil biological activity under herbicide application is compulsory requested for all herbicides pro- posed for registration. Special attention is needed concern- ing sulfonyl-urea, ?-hydroxy pyridine and several non- selective herbicides used due to the shortage in informa- tion and their extention of use. A number of 11 herbicides were tested for their effect on soil respiration, nitrogen

Lucian Ghinea; Maria Iancu; Mariana Turcu

5

The effect of a bacterial-humus preparation on the biological activity of soils  

NASA Astrophysics Data System (ADS)

The influence of the Gumigel bacterial-humus preparation on the biological activity of soils was investigated. The activity was assessed by the respiration intensity of the soil microorganisms, the total number of bacteria, and the structure of the saprotrophic bacterial complex. It was demonstrated that the microorganisms were preserved in the preparation for a long time. As this preparation was kept at 4°C, the number of microorganisms was preserved at a permanent level during no less than half a year. The preparation did not have a significant effect on the biological activity of the unpolluted soil, but it intensified the biological activity in the case of the polluted soil, which was seen from an increase in the number of microorganisms and their respiration intensity.

Tsyganova, E. N.; Zvyagintsev, D. G.; Lysak, L. V.; Stepanov, A. L.

2013-07-01

6

Soil Biology and Ecology.  

National Technical Information Service (NTIS)

The term 'Soil Biology', the study of organism groups living in soil, predates 'Soil Ecology', the study of interactions between soil organisms as mediated by the soil physical environment. Soil Ecology evolved between the late 1950's and the 1970's from ...

P. T. Rygiewicz E. R. Ingham

1993-01-01

7

Evaluating the biological activity of oil-polluted soils using a complex index  

NASA Astrophysics Data System (ADS)

A complex index characterizing the biological activity of soils (BAS) is suggested. It is based on an estimate of the level of activity of catalase; the number of heterotrophic and hydrocarbon oxidizing microorganisms, microscopic fungi, algae, and cyanobacteria; and the degree of development of higher plants and insects in the studied soil. The data on using the BAS coefficient for evaluating the efficiency of rehabilitation measures for oil-polluted soils are given. Such measures included introducing the following biological preparations: Lenoil based on a natural consortium of microorganisms Bacillus brevis and Arthrobacter sp.; the Azolen biofertilizer with complex action based on Azotobacter vinelandii; the Belvitamil biopreparation, which is the active silt of pulp and paper production; and a ready-mixed industrial association of aerobic and anaerobic microorganisms that contains hydrocarbon oxidizing microorganisms of the Arthrobacter, Bacillus, Candida, Desulfovibrio, and Pseudomonas genera.

Kabirov, R. R.; Kireeva, N. A.; Kabirov, T. R.; Dubovik, I. Ye.; Yakupova, A. B.; Safiullina, L. M.

2012-02-01

8

TILLAGE IMPACTS ON SOIL BIOLOGICAL ACTIVITY AND AGGREGATE STABILITY IN BRAZILIAN CERRADO OXISOLS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Mechanized agriculture is increasing rapidly in the Cerrado region of Brazil, increasing concerns about water quality, off-site impacts, and sustainability. Our objective was to determine the impact of tillage on soil biological activity and aggregate stability on an Oxisol typical of the region. Th...

9

Assessment of the biological activity of soils in the subtropical zone of Azerbaijan  

NASA Astrophysics Data System (ADS)

The enzymatic activity; the microbial population; and the intensities of the nitrification, ammonification, CO2emission, and cellulose decomposition were studied in gray-brown, meadow-sierozemic, meadow-forest alluvial, and yellow (zheltozem) gley soils in the subtropical zone of Azerbaijan under natural vegetation, crop rotation systems with vegetables, and permanent vegetable crops. On this basis, the biological diagnostics of these soils were suggested and the soil ecological health was evaluated. It was shown that properly chosen crop rotation systems on irrigated lands make it possible to preserve the fertility of the meadow-forest alluvial and zheltozem-gley soils and to improve the fertility of the gray-brown and meadow-sierozemic soils.

Babaev, M. P.; Orujova, N. I.

2009-10-01

10

[Effect of the vegetative cover on the biological activity of the soil of Chaco Arido].  

PubMed

Vegetation plays a primal role in arid ecosystems, since it creates microclimate conditions that moderate the characteristics of the region whereby the rational use of vegetal resources is fundamental. Felling, clearing and overgrazing lead to decrease in organic contribution and stimulate soil compaction, causing an alteration of microbial activity, with losses in nutrient turnover. The global biological activity is a soil parameter easy to obtain and indicates the presence and diversity of soil life as well as substrate availability and is useful in order to characterize soil potential fertility. This work was carried out in Natural Forest Reserve Chancaní, Province of Córdoba (Argentina), which is representative of Argentine Dry Chaco. Dominant tree species are: Prosopis flexuosa and Aspidosperma quebracho blanco. The global biological activity (GBA) was measured along one year, under trees, under shrubs and in interspaces. Soil samples were taken monthly from plots with four management systems: 1) forest, ii) selective clearing (only dominant species remain), iii) bush (clearing invaded by Larrea sp) and iv) grazing (cleared area, neither trees nor shrubs). GBA was evaluated using the CO2 release method, after ten days of incubation. It is concluded that in the plots with grasses and under the trees GBA was higher than with other treatments. The lesser GBA was detected in bushes and interspaces. All differences were more prominent during extreme temperature months. No significant difference between both species of dominant trees was observed. PMID:8210407

Abril, A; Acosta, M; Bachmeier, O; Rollan, A

1993-01-01

11

Soil Biological Communities  

NSDL National Science Digital Library

The Bureau of Land Management (BLM) in Idaho provides this electronic resource on soil communities. With introductory text, illustrations, and references, these pages provide a general overview of soil communities, including Biological Crusts, Fungi, Bacteria, Protozoa, Nematodes, and Arthropods. The site also introduces general readers to Soil Food Webs and Burrowing Mammals, with an emphasis on the western United States. A series of select links to soil-related resources rounds out the site.

2000-01-01

12

Soil biological activity and their seasonal variations in response to long-term application of organic and inorganic fertilizers  

Microsoft Academic Search

The objectives of this study were to explore the effects of long-term and continued application of fertilizers and manures\\u000a on microbial biomass, soil biological activity and their seasonal variations in surface and subsurface soils in relation to\\u000a soil fertility. For this, soils were sampled in spring, summer and autumn from Shenyang Long-term Experimental Station, northeastern\\u000a China. The results showed that

Gaofei Ge; Zhaojun Li; Fenliang Fan; Guixin Chu; Zhenan Hou; Yongchao Liang

2010-01-01

13

[Effects of biological regulated measures on active organic carbon and erosion-resistance in the Three Gorges Reservoir region soil].  

PubMed

To gain a better knowledge of characteristics of soils and provide a scientific basis for soil erosion control in the Three Gorges Reservoir Area, contents of aggregates and total soil organic carbon (SOC), as well as soil active organic carbon fractions including particulate organic carbon (POC), readily oxidized organic carbon (ROC), dissolved organic carbon (DOC), microbial biomass carbon (MBC) in the 0-30 cm soil layer under seven different biological regulated measures were studied by the field investigation combined with the laboratory analysis. Results showed that the content of the SOC and active organic carbon fractions decreased with the increasing soil depth; the content of the SOC and active organic carbon fractions in 0-10 cm was significantly higher than that in 20-30 cm. The stability of soil aggregates were also significantly influenced by biological regulated measures, the content of > 0.25 mm water-stable aggregates in seven types of biological regulated measures was in the order of Koelreuteria bipinnata + Cassia suffruticasa > hedgerows > closed forest > natural restoration > economic forest > traditional planting > control plot, moreover, the content of 0.25 mm water-stable aggregates correlated positively with the content of SOC. Soils under different biological regulated measures all demonstrated fractal features, and soil under the measure of Koelreuteria bipinnata + Cassia suffruticasa was found to have the lowest value of fractal dimension and soil erodiable K, indicating a relatively strong structure stability and erosion-resistant capacity. Negative correlation was observed when compared the content of active organic carbon fractions with the soil erodiable K. It can be concluded that properties of soil can be managed through biological regulated measures; thence had an influence on the soil erosion-resistant capacity. PMID:24028016

Huang, Ru; Huang, Lin; He, Bing-Hui; Zhou, Li-Jiang; Yu, Chuan; Wang, Feng

2013-07-01

14

EFFECT OF NITROGEN AND METAL ADDITIONS ON NITROGEN FIXATION ACTIVITY IN BIOLOGICAL SOIL CRUSTS  

Microsoft Academic Search

Biological soil crusts (BSCs) are diverse consortia of microorganisms that live in intimate association with soils in arid environments. Also called cryptogamic or microbiotic crusts, these communities can include cyanobacteria, algae, heterotrophic bacteria, fungi, lichens, and mosses. Together, these organisms provide many services to their surrounding ecosystems, including reduction of water runoff, promotion of water infiltration, and prevention of soil

K. Alexander; D. Lui; A. D. Anbar; F. Garcia-Pichel; H. E. Hartnett

2009-01-01

15

Effect of straws from Bt-transgenic rice on selected biological activities in water-flooded soil  

Microsoft Academic Search

The biochemical properties of soil have often been described as early and sensitive indicators of ecological changes in both natural soil and agroecosystem. In the current study, the impacts of the amendment of Bt-transgenic rice (KMD) straw on biological activities in water-flooded soil were investigated under laboratory conditions and compared with non-transgenic rice (Xiushui 11) straw. The results showed that

Wei-xiang Wu; Qing-fu Ye; Hang Min

2004-01-01

16

Organic matter and biological activity of postagrogenic soils in the southern taiga using the example of Kostroma oblast  

NASA Astrophysics Data System (ADS)

The dynamics of the humus status (some indices) and the biological activity of agrosoddy-podzolic soils in the course of the natural forest regeneration were studied based on the example of the soils of two succession series, which differed both in their parent rock and the history of their development. Upon the overgrowing of the croplands, the humus content increased, and its distribution within the soil profile became more differentiated. As a hayfield was overgrown, the humus content decreased to some extent at the earliest stages. The parameters of the humus status more clearly changed in the succession series with the light-textured soils, which had a relatively simple history of agricultural development. The biological activity mainly decreased at the earlier succession stages and became higher with the increasing productivity and greater amounts of easily decomposing falloff entering the soil. This relationship was especially distinctly revealed in the grass communities.

Vladychenskii, A. S.; Telesnina, V. M.; Rumyantseva, K. A.; Chalaya, T. A.

2013-05-01

17

Persistence and biological activity in soil of the insecticidal proteins from Bacillus thuringiensis , especially from transgenic plants  

Microsoft Academic Search

Insecticidal proteins produced by various subspecies (kurstaki, tenebrionis, and israelensis) of Bacillus thuringiensis (Bt) bound rapidly and tightly on clays, both pure mined clay minerals and soil clays, on humic acids extracted from soil, and\\u000a on complexes of clay and humic acids. Binding reduced susceptibility of the proteins to microbial degradation. However, bound\\u000a proteins retained biological activity. Purified Cry1Ab protein

G. Stotzky

2005-01-01

18

Biological Soil Crusts: Characteristics and Distribution  

Microsoft Academic Search

\\u000a Biological soil crusts result from an intimate association between soil particles and cyanobacteria, algae, microfungi, lichens,\\u000a and bryophytes (in different proportions) which live within, or immediately on top of, the uppermost millimeters of soil.\\u000a Soil particles are aggregated through the presence and activity of these biota, and the resultant living crust covers the\\u000a surface of the ground as a coherent

J. Belnap; B. Büdel; O. L. Lange

19

Variation of stabilised, microbial and biologically active carbon and nitrogen in soil under contrasting land use and agricultural management practices.  

PubMed

Land use and agricultural practices modify both the amounts and properties of C and N in soil organic matter. In order to evaluate land use and management-dependent modifications of stable and labile C and N soil pools, (i). organic C and total N content, (ii). microbial (C(mic)) and N (N(mic)) content and (iii). C and N mineralisation rates, termed biologically active C and N, were estimated in arable, grassland and forest soils from northern and southern Germany. The C/N-ratios were calculated for the three levels (i)-(iii) and linked to the eco-physiological quotients of biotic-fixed C and N (C(mic)/C(org), N(mic)/N(t)) and biomass-specific C and N mineralisation rate (qCO(2), qN(min)). Correlations could mainly be determined between organic C, total N, C(mic), N(mic) and C mineralisation for the broader data set of the land use systems. Generally, the mineralisation activity rate at 22 degrees C was highly variable and ranged between 0.11 and 17.67 microg CO(2)-C g(-1) soil h(-1) and -0.12 and 3.81 microg (deltaNH(4)(+)+deltaNO(3)(-))-N g(-1) soil h(-1). Negative N data may be derived from both N immobilisation and N volatilisation during the experiments. The ratio between C and N mineralisation rate differed significantly between the soils ranging from 5 to 37, and was not correlated to the soil C/N ratio and C(mic)/N(mic) ratio. The C/N ratio in the 'biologically active' pool was significantly smaller in soils under conventional farming than those under organic farming systems. In a beech forest, it increased from the L, Of to the Ah horizon. The biologically active C and N pools refer to the current microbial eco-physiology and are related to the need for being C and N use efficient as indicated by metabolic qCO(2) and qN(min) quotients. PMID:12738293

Dilly, Oliver; Blume, Hans-Peter; Sehy, Ulrike; Jimenez, Miguel; Munch, Jean Charles

2003-07-01

20

Bulk soil and rhizosphere bacterial community PCR–DGGE profiles and ?-galactosidase activity as indicators of biological quality in soils contaminated by heavy metals and cultivated with Silene vulgaris (Moench) Garcke  

Microsoft Academic Search

The biological quality of two heavy metal contaminated soils (soil C: Typic Calcixerept, pH 8.3 and soil H: Typic Haploxeraf, pH 7.3) was investigated after growing the metal-tolerant plant Silene vulgaris (Moench) Garcke for two vegetative periods. The activity of the enzyme ?-galactosidase, which is sensitive to the presence of contaminants in soil, and the polymerase chain reaction-denaturing gradient gel

M. J. Martínez-Iñigo; A. Pérez-Sanz; I. Ortiz; J. Alonso; R. Alarcón; P. García; M. C. Lobo

2009-01-01

21

Soil amendment with Pseudomonas fluorescens CHA0: lasting effects on soil biological properties in soils low in microbial biomass and activity.  

PubMed

Pseudomonas fluorescens strains are used in agriculture as plant growth-promoting rhizobacteria (PGPR). Nontarget effects of released organisms should be analyzed prior to their large-scale use, and methods should be available to sensitively detect possible changes in the environments the organism is released to. According to ecological theory, microbial communities with a greater diversity should be less susceptible to disturbance by invading organisms. Based on this principle, we laid out a pot experiment with field-derived soils different in their microbial biomass and activity due to long-term management on similar parent geological material (loess). We investigated the survival of P. fluorescens CHA0 that carried a resistance toward rifampicin and the duration of potential changes of the soil microflora caused by the inoculation with the bacterium at the sowing date of spring wheat. Soil microbial biomass (C(mic), N(mic)) basal soil respiration (BR), qCO(2), dehydrogenase activity (DHA), bacterial plate counts, mycorrhiza root colonization, and community level substrate utilization were analyzed after 18 and 60 days. At the initial stage, soils were clearly different with respect to most of the parameters measured, and a time-dependent effect between the first and the second set point were attributable to wheat growth and the influence of roots. The effect of the inoculum was small and merely transient, though significant long-term changes were found in soils with a relatively low level of microbial biomass. Community level substrate utilization as an indicator of changes in microbial community structure was mainly changed by the growth of wheat, while other experimental factors were negligible. The sensitivity of the applied methods to distinguish the experimental soils was in decreasing order N(mic), DHA, C(mic), and qCO(2). Besides the selective enumeration of P. fluorescens CHA0 rif(+), which was only found in amended soils, methods to distinguish the inoculum effect were DHA, C(mic), and the ratio of C(mic) to N(mic). The sampling time was most sensitively indicated by N(mic), DHA, C(mic), and qCO(2). Our data support the hypothesis-based on ecosystem theory-that a rich microflora is buffering changes due to invading species. In other words, a soil-derived bacterium was more effective in a relatively poor soil than in soils that are rich in microorganisms. PMID:19224270

Fliessbach, Andreas; Winkler, Manuel; Lutz, Matthias P; Oberholzer, Hans-Rudolf; Mäder, Paul

2009-02-18

22

Antibiotic Pigment from Desert Soil Actinomycetes; Biological Activity, Purification and Chemical Screening  

PubMed Central

An actinomycete strain, Streptomyces hygroscopicus subsp. ossamyceticus (strain D10) was isolated from Thar Desert soil, Rajasthan during the year 2006 and found to produce a yellow color pigment with antibiotic activity. Crude pigment was produced from strain D10 by solid state fermentation using wheat bran medium followed by extraction with ethyl acetate. The antimicrobial activity of the crude pigment was evaluated against drug resistant pathogens such as methicillin-resistant Staphylococcus aureus, vancomycin-resistant Staphylococcus aureus, extended spectrum ?-lactamase producing cultures of Escherichia coli, Pseudomonas aeruginosa and Klebsiella sp. About 420 mg of crude pigment was produced per 10 g of wheat bran medium. In the disc diffusion method the crude ethyl acetate extract showed a minimum of 10 mm inhibition against Klebsiella sp. and maximum of 19 mm of inhibition against Escherichia coli. The crude pigment was partially purified using thin layer chromatography with the solvent system chloroform:methanol (30:70) and the Rf value was calculated as 0.768. Antimicrobial activity of the partially purified compound from thin layer chromatography was determined using the bioautography method. The purified pigment showed minimum of 15 mm inhibition against Klebsiella sp. and a maximum of 23 mm of inhibition against vancomycin-resistant Staphylococcus aureus in the disc diffusion method. Based on the results of chemical screening, the pigment was tentatively identified as group of sugar containing molecules.

Selvameenal, L.; Radhakrishnan, M.; Balagurunathan, R.

2009-01-01

23

FATE OF PAH COMPOUNDS IN TWO SOIL TYPES: INFLUENCE OF VOLATILIZATION, ABIOTIC LOSS, AND BIOLOGICAL ACTIVITY  

EPA Science Inventory

The fate of 14 polycyclic aromatic hydrocarbon (PAH) compounds was evaluated with regard to interphase transfer potential and mechanisms of treatment in soil under unsaturated conditions. Volatilization and abiotic and biotic fate of the PAHs were determined using two soils not p...

24

FATE OF PAH COMPOUNDS IN TWO SOIL TYPES: INFLUENCE OF VOLATILIZATION, ABIOTIC LOSS AND BIOLOGICAL ACTIVITY  

EPA Science Inventory

The fate of 14 polycyclic aromatic hydrocarbon (PAH) compounds was evaluated with regard to interphase transfer potential and mechanisms of treatment in soil under unsaturated conditions. olatilization and abiotic and biotic fate of the PAHs were determined using two soils not pr...

25

Biological properties of soils on mine tips  

NASA Astrophysics Data System (ADS)

The biological properties of soils forming on coalmine spoils composed of loose non-toxic rocks were studied. In ten years of observation, fungal biomass in the studied soils increased by 6 times; the population density of the main groups of bacteria, by 3-7 times, and the respiration intensity, by 5-6 times. The biochemical activity of the soils increased significantly; in particular, the enzymatic activity (especially, the hydrolase activity) increased by 3-8 times, and the processes of cellulose destruction and accumulation of ninhydrinpositive products intensified. The obtained results attest to colonization of the substrate by microorganisms and the development of microbial cenoses. This process is particularly active upon application of phytoameliorants.

Naprasnikova, E. V.

2008-12-01

26

Bulk soil and rhizosphere bacterial community PCR-DGGE profiles and beta-galactosidase activity as indicators of biological quality in soils contaminated by heavy metals and cultivated with Silene vulgaris (Moench) Garcke.  

PubMed

The biological quality of two heavy metal contaminated soils (soil C: Typic Calcixerept, pH 8.3 and soil H: Typic Haploxeraf, pH 7.3) was investigated after growing the metal-tolerant plant Silene vulgaris (Moench) Garcke for two vegetative periods. The activity of the enzyme beta-galactosidase, which is sensitive to the presence of contaminants in soil, and the polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) profiles of 16S rRNA gene fragments of culturable bacteria from bulk soil and rhizosphere were determined. The microbial enzymatic activity was higher in planted soils than in bare soils at the contamination level of 600 mg of total heavy metals kg(-1) soil. After growing S. vulgaris, beta-galactosidase activity was almost recovered in the calcareous soil. In this soil new bands appeared in the PCR-DGGE profiles of the rhizosphere bacterial community as a response to the exposure to heavy metals. PMID:19345981

Martínez-Iñigo, M J; Pérez-Sanz, A; Ortiz, I; Alonso, J; Alarcón, R; García, P; Lobo, M C

2009-04-05

27

Biological Control on Mineral Transformation in Soils ?  

NASA Astrophysics Data System (ADS)

Weathering of primary minerals is commonly linked to biological processes through the production of carbonic and organic acids. Plants can also play a role in weathering by removing soluble constituents and enhancing diffusion gradients within the soil. Here we investigate the synthesis of secondary minerals and the role of plants in removing elements that act as building blocks for these minerals. In order to minimize losses from leaching, we have sampled a chronosequence of soils forming on lava flows on Hawaii Island that receive about 200 mm of rain annually and have never been subjected to high levels of rainfall. The P concentration in the soils drops from almost 3000 mg/kg on a 1.5 ky lava flow to around 1000 mg/kg on a 350 ky lava flow. This loss of P can only be ascribed to P-uptake by plants with subsequent removal through the loss of above ground biomass through fire and/or wind removal. Over the same time frame the amount of plagioclase in the soils drops from around 22% of the <2 mm soil fraction on the youngest lava flow to virtually 0% on the 350 ky flow, suggesting a substantial release of Si. Elevated silicon in arid, basaltic soil environments often leads to formation of smectite, a feature not observed along the chronosequence. In fact, plagioclase is replaced by the kaolin mineral halloysite with allophane as an apparent precursor. Kaolin minerals are associated with moderate to intense leaching environments rather than the mild leaching conditions that influence these soils. We selected an intermediate age soil profile (170 ky lava flow) to conduct an in-depth investigation of the soil mineral composition. We detected a strong dominance of halloysite, the presence of gibbsite, but no smectite. Secondary halloysite formation is preferred over smectite formation when Si activities are relatively low, and the pH is acidic rather than alkaline. Although this mineral assemblage seems to imply formation under a wetter climatic regime, the oxygen isotopic composition of the halloysite suggests formation under soil environmental conditions similar to the present. The Si concentration in grass and tree leaves in the vicinity of the soil contain between 3 and 8% Si. Loss of these leaves to the nearby ocean (either as dried or burned residue) could be responsible for considerable Si removal in a manner similar to the P-removal. The resulting Si-deficient soil-water favors the formation of halloysite over smectite as is demonstrated by construction of mineral stability diagrams using the soil-water data from the soils along the chronosequence.

Ziegler, K.; Hsieh, J. C.; Chadwick, O. A.; Kelly, E. F.

2001-12-01

28

Long-term effects of intercropping and bio-litter recycling on soil biological activity and fertility status of sub-tropical soils.  

PubMed

On-farm field experiments were carried out at two sites having 38- and 10-year-old orchard cropping systems under sub-tropical climatic regions to evaluate changes in organic carbon accumulation and chemical and microbiological properties of the soils. Under a system of different intercropped fruit trees, the cultivation of coconut (Cocos nucifera L.) intercropped with guava (Psidium guajava L.) enhanced the soil microbial activity approximately 2-fold after 38 yrs over 10 yrs of the same intercropped system. Soil organic carbon increased from 3.4 to 7.8 and 2.4 to 6.2 g kg-1 after 38 and 10 yrs, respectively, following the establishment of orchards. The increase was attributed to greater recycling of bio-litters. Levels of dehydrogenase, phosphatase and soil microbial biomass under field conditions generally depended more on the nature of the cropping system than on soil types. Similarly, average carbon inputs of bio-litter to the soil in monocrop (0.98 Mg ha-1 yr-1) was less than intercropped fruit trees (2.07 Mg ha-1 yr-1). The average level of soil microbial biomass carbon was 1158 kg ha-1 (0-0.15 m depth) and the organic carbon turnover rate was 8.5 yr-1 after 38 yrs of intercropped fruit trees, which resulted in a lower ratio (1.81) of carbon inputs to soil microbial biomass carbon. PMID:11131798

Manna, M C; Singh, M V

2001-01-01

29

Changes in the biological activity of chestnut soils upon the long-term application of fertilizers in a rotation with oil-bearing crops  

NASA Astrophysics Data System (ADS)

Experimental studies showed that irrigated chestnut soils on the piedmont of the Zailiiskiy Alatau Range are characterized by the moderate activity of the hydrolytic and redox enzymes. The use of these soils in the crop rotation system increases the hydrolytic activity of the enzymes (invertase, urease, and ATP synthase) by 30% in comparison with the monoculture; at the same time, it does not have a significant impact on the changes in the biological activity of the redox enzymes (catalase and dehydrogenase). The hydrolytic activity of the soils is activated to a greater extent in the crop rotation and in the monoculture against the background application of organic fertilizers. In this case, the recommended rates of mineral fertilizers do not inhibit the activity of the hydrolytic and redox enzymes. An increase in the hydrolytic activity of the enzymes directly affects the yield of oilseed flax. Therefore, indices of the hydrolytic activity of soils can be used as a test for the diagnostics of the efficiency of fertilizers both in crop rotation and monoculture systems.

Eleshev, R. E.; Bakenova, Z. B.

2012-11-01

30

An Introduction to Biological Soil Crusts  

NSDL National Science Digital Library

Biological soil crusts are the feature of this USGS Canyonlands Research Station website. The site provides an introduction to biological soil crusts with linked images, divided into the following topics: nomenclature of the crusts- crytogamic, microbiotic, crytobiotic, and microphytic crusts, structure and formation, species composition, ecological functions, response to disturbance, future, and a glossary. In addition, the site provides links to other Canyonlands Research Station webages including an advanced page with a downloadable 90-page report on soil crusts, a gallery of biological soil crust images and figures, references, the Canyon Country Ecosystems Research Site (CCERS), and other related links.

Station, Usgs C.; Usgs

31

Soil as a biological system  

Microsoft Academic Search

Soil plays a fundamental and irreplaceable role in the biosphere because it gov- erns plant productivity of terrestrial ecosystem, allows the completion of the biogeochem- ical cycles and microorganisms inhabiting soil degrade, sooner or later, all organic com- pounds including those more recalcitrant. The main characteristics of soil are the domina- tion of the solid phase, the presence of aqueous

G. PIETRAMELLARA; J. ASCHER; M. T. CECCHERINI; G. RENELLA

2002-01-01

32

[Effects of biological soil crust on soil erodibility in Hilly Loess Plateau region of Northwest China].  

PubMed

Based on the analysis of the effects of biological soil crust (biocrust) in re-vegetated grasslands on soil physical and chemical properties, and by using EPIC estimation model in combining with simulated rainfall trials, this paper studied the effects of biocrust with different biomass and different soil texture on the soil erodibility (K value) in Hilly Loess Plateau Region of Northwest China in different seasons. The results showed biocrust could significantly decrease soil erodibility, with the K value of biocrust soil decreased by about 17%, compared with subsoil. The soil erodibility decreased with the increasing biomass of biocrust. The K value of moss crust soil decreased by 21%, compared with cyanobacteria crust soil. The erodibiliy of biocrust soil differed with different seasons, being significantly higher in rainy season than before or after the rainy season due to the differences in the biological activity of the biocrust organisms. The erodibilty of biocrust soil with different texture also varied significantly, with the K value in the order of sandy loam soil > silt soil > sandy soil. The measurement under simulated rainfall showed that the development of biocrust could decrease the erodibility of biocrust soil by about 90%, compared with that of the subsoil (5-10 cm). PMID:23717997

Gao, Li-Qian; Zhao, Yun-Ge; Qin, Ning-Qiang; Zhang, Guo-Xiu

2013-01-01

33

Effects of chemical, biological, and physical aging as well as soil addition on the sorption of pyrene to activated carbon and biochar.  

PubMed

In this study, the suitability of biochar and activated carbon (AC) for contaminated soil remediation is investigated by determining the sorption of pyrene to both materials in the presence and absence of soil and before as well as after aging. Biochar and AC were aged either alone or mixed with soil via exposure to (a) nutrients and microorganisms (biological), (b) 60 and 110 °C (chemical), and (c) freeze-thaw cycles (physical). Before and after aging, the pH, elemental composition, cation exchange capacity (CEC), microporous SA, and sorption isotherms of pyrene were quantified. Aging at 110 °C altered the physicochemical properties of all materials to the greatest extent (for example, pH increased by up to three units and CEC by up to 50% for biochar). Logarithmic K(Fr) values ranged from 7.80 to 8.21 (ng kg(-1))(ng L(-1))(-nF) for AC and 5.22 to 6.21 (ng kg(-1))(ng L(-1))(-nF) for biochar after the various aging regimes. Grinding biochar to a smaller particle size did not significantly affect the sorption of d(10) pyrene, implying that sorption processes operate on the subparticle scale. Chemical aging decreased the sorption of pyrene to the greatest extent (up to 1.8 log unit for the biochar+soil). The sorption to AC was affected more by the presence of soil than the sorption to biochar was. Our results suggest that AC and biochar have a high sorption capacity for pyrene that is maintained both in the presence of soil and during harsh aging. Both materials could therefore be considered in contaminated land remediation. PMID:22077986

Hale, Sarah E; Hanley, Kelly; Lehmann, Johannes; Zimmerman, Andrewr; Cornelissen, Gerard

2011-11-28

34

Metadata Activities in Biology  

SciTech Connect

The National Biological Information Infrastructure program has advanced the biological sciences ability to standardize, share, integrate and synthesize data by making the metadata program a core of its activities. Through strategic partnerships, a series of crosswalks for the main biological metadata specifications have enabled data providers and international clearinghouses to aggregate and disseminate tens of thousands of metadata sets describing petabytes of data records. New efforts at the National Biological Information Infrastructure are focusing on better metadata creation and curation tools, semantic mediation for data discovery and other curious initiatives.

Inigo, Gil San [University of New Mexico, Albuquerque; HUTCHISON, VIVIAN [USGS; Frame, Mike [USGS; Palanisamy, Giri [ORNL

2010-01-01

35

Effects of Heavy Metals on Soil Enzyme Activities  

Microsoft Academic Search

The pollution of the soil with heavy metals is one of the worst legacies of our intensive agricultural–industrial activities,\\u000a and it negatively affects various characteristics of the soil, including soil enzyme activities. Soil enzymes are natural\\u000a molecules that catalyze soil microbial reactions and mainly originate from microorganisms and plants. Since enzyme activities\\u000a play fundamental roles in soil chemical and biological

Ayten Karaca; Sema Camci Cetin; Oguz Can Turgay; Ridvan Kizilkaya

36

The role of biological soil crusts on soil moisture  

NASA Astrophysics Data System (ADS)

In water-limited ecosystems, water becomes the most important driver for plant productivity. In these systems, spatial distribution of water resources is not random but organized into a mosaic of water-depletion areas linked to water-accumulation areas. In other words, water is transferred from interplant patches that act as source areas to vegetation patches that act as sinks of this resource. Thus, structure and functioning of interplant patches have a decisive role in water redistribution and distribution patterns of vegetation. Soil surface in the interplant spaces of most arid and semiarid ecosystems is covered by biological soil crusts (BSCs). These organisms regulate water fluxes into and through soils and play major roles in local hydrological processes. In the last years, the role of these organisms in infiltration and runoff has gained increased importance and a better knowledge about their effects on these processes has been acquired. However, the role of BSCs in other important components of the water balance such as evaporation or soil moisture has been scarcely studied, so that their effects on these processes remain unknown. The objective of this work is to examine the influence of BSCs on soil moisture regimes in the top profile of the soil in two semiarid ecosystems of SE Spain with contrasting soil texture and where BSCs are well-represented. Soil moisture content at 0.03 and 0.10 m was monitored under two representative types of BSCs, a dark cyanobacteria-dominated BSC and a light-coloured lichen-dominated BSC, and in soils where these BSCs were removed by scraping, at both study sites. Our results show that, under high water conditions, removal of BSCs leads to a decrease in soil moisture compared to soils covered by BSCs. Decrease in soil moisture due to BSC removal namely affects moisture in the upper layer of the soil (0.03 m), but has little impact in deeper soil (0.10 m). Evaporation is also generally faster in soils with no BSCs than in soils covered by them. The type of BSC influences soil moisture in a different way depending on soil water conditions. Under high water content conditions, soil water loss is faster and soil moisture content lower under cyanobacterial than under lichen BSCs, due to higher infiltration promoted by lichens. On the contrary, under low water content conditions, lichen-crusted soils dry out faster and exhibit less moisture than cyanobacteria-crusted ones, attributed to the larger porosity and subsequent greater evaporative losses in lichen- than in cyanobacteria-crusted soils. We found higher moisture in coarse-textured soils than in fine-textured ones, despite the higher water retention capacity of the latter soils. More favourable conditions in the coarser soils, which had greater organic matter content, aggregate stability and were subject to less water stress due to its proximity to the coast, seems to contribute to this increased soil moisture content. BSCs therefore play an important role on the maintenance of water availability in the interplant spaces, thereby strongly affecting soil physical and biological processes, and the potential for emergence establishment and survival of plants in semiarid ecosystems.

Chamizo, S.; Cantón, Y.; Lázaro, R.; Rodriguez-Caballero, E.; Domingo, F.

2012-04-01

37

Roles of biological activities, chemical reactions, physical forces, and aboveground management in soil macroaggregate formation and stabilization  

Technology Transfer Automated Retrieval System (TEKTRAN)

Soil functions or ecosystem services depend on the distribution of macro- (= 0.25 mm) and micro- (< 0.25 mm) aggregates and open space between aggregates. It is the arrangement of the aggregates and pore space which allows air and water movement in and out of soil; reduces compaction; and stimulates...

38

Biological residues define the ice nucleation properties of soil dust  

NASA Astrophysics Data System (ADS)

Soil dust is a major driver of ice nucleation in clouds leading to precipitation. It consists largely of mineral particles with a small fraction of organic matter constituted mainly of remains of micro-organisms that participated in degrading plant debris before their own decay. Some micro-organisms have been shown to be much better ice nuclei than the most efficient soil mineral. Yet, current aerosol schemes in global climate models do not consider a difference between soil dust and mineral dust in terms of ice nucleation activity. Here, we show that particles from the clay and silt size fraction of four different soils naturally associated with 0.7 to 11.8 % organic carbon (w/w) can have up to four orders of magnitude more ice nuclei per unit mass active in the immersion freezing mode at -12 °C than montmorillonite, the most efficient pure clay mineral. Most of this activity was lost after heat treatment. Removal of biological residues reduced ice nucleation activity to, or below that of montmorillonite. Desert soils, inherently low in organic content, are a large natural source of dust in the atmosphere. In contrast, agricultural land use is concentrated on fertile soils with much larger organic matter contents than found in deserts. It is currently estimated that the contribution of agricultural soils to the global dust burden is less than 20 %. Yet, these disturbed soils can contribute ice nuclei to the atmosphere of a very different and much more potent kind than mineral dusts.

Conen, F.; Morris, C. E.; Leifeld, J.; Yakutin, M. V.; Alewell, C.

2011-06-01

39

Quantitative molecular biology and gas flux measurements demonstrate soil treatment and depth affects on the distribution and activity of denitrifiers  

NASA Astrophysics Data System (ADS)

The growing industrialisation of agriculture has led to a dramatic increase in organic and inorganic nitrogen (N) fertiliser inputs to agro-ecosystems. This increase has had negative effects on the quality of water ecosystems and greenhouse gas emissions.The study objective was to quantify denitrification and denitrifying microorganisms, using real-time PCR assays of the nitrite reductase(nir) and nitrous oxide reductase(nos) functional gene copy concentrations (GCC g[soil]-1) in Irish agricultural surface and subsoils. Soil cores from 3 soil horizons (A:0-10 cm; B:45-55 cm; C:120-130cm) were amended with 3 alternate N- and C-source amendments (NO3-; NO3-+glucose-C; NO3-+Dissolved Organic Carbon (DOC). Real-time production of N2O and N2 was recorded by gas chromatography in a specialized He/O2 environment. N2O and Total Denitrification (TDN) (N2O+N2) production was generally greater in surface soil (2.052 mg/kg/d TDN) than in subsoils (0.120 mg/kg/d TDN). The abundance of denitrifying nirS, nirK (nir) and nos genes was higher in the surface soil, decreasing with soil depth, except in incubations amended with NO3- and DOC, where the carbon source directly positively affected gene copy numbers and fluxes of N2O and N2 production. C addition increased soil denitrification rates, and resulted in higher N2O/(N2O+N2) ratios in surface soil (0.39) than subsoils (0.005), indicating that the subsoil had higher potential for complete reduction of N2O to N2. In the subsoils, complete reduction of NO3- due to glucose-C and DOC addition was observed. Interestingly, at all 3 soil depths, lower nirK abundance (2.78 105 GCC) was recorded, compared to nirS (1.45 107 GCC), but the overall abundance of nir (S+K) i.e. (1.54 107GCC), corresponded with N2O emission fluxes (3.34 mg/kg/d) Statistical analysis indicates negative correlation between nirK GCC and N2O production, but a strong positive correlation was observed between nirS GCC and N2O. We therefore hypothesize that the potential for complete nitrate reduction can be inferred using the relationship - ([nirS + nirK] - nosZ): (nosZ). Specifically, at 45-55 cm depth ([nirS + nirK] - nosZ): (nosZ) ratios were lower (2.13) compared to 120-130cm (94.4), overall the ([nirS + nirK] - nosZ): (nosZ) ratios for horizons A, B and C, was 27.9, 40.3, 69.4, respectively, thus decreasing potential for full microbial denitrification with decreasing depth. Mean Bac:nir and Bac:nosZ gene copy ratios g[soil]-1 increased from horizon A(Bac:nir - 3.91) (Bac:nosZ - 111.24) to horizon B (Bac:nir - 8.89) (Bac:nosZ -295.0 ), and decreased again in horizon C (Bac:nir - 0.723) (Bac:nosZ - 46.2) . Overall, denitrification in subsoils occurs at a lower rate than surface soils, but the microbial populations favored more complete reduction thus reducing emissions of NO3- to water and N2O to the atmosphere. The gene copy ratio suggests that the soil microbial community containing nirs and nosZ genes act as the driving force, and in the partitioning of N2O and N2 emissions from soil.

Barrett, M. M.; Jahangir, M.; Cardenas, L.; Khalil, M.; Richards, K. R.; O'Flaherty, V.

2010-12-01

40

Long-term effects of intercropping and bio-litter recycling on soil biological activity and fertility status of sub-tropical soils  

Microsoft Academic Search

On-farm field experiments were carried out at two sites having 38- and 10-year-old orchard cropping systems under sub-tropical climatic regions to evaluate changes in organic carbon accumulation and chemical and microbiological properties of the soils. Under a system of different intercropped fruit trees, the cultivation of coconut (Cocos nucifera L.) intercropped with guava (Psidium guajava L.) enhanced the soil microbial

M. C Manna; M. V Singh

2001-01-01

41

Disturbance and Recovery of Biological Soil Crusts  

Microsoft Academic Search

\\u000a Disturbance can profoundly affect the cover, species composition, and the physiological functioning of biological soil crusts.\\u000a The disturbances we discuss include air pollution; exposure to oil, herbicides, and pesticides; invasion by annual exotic\\u000a weeds; mechanical disturbances such as human and livestock trampling (see Chap. 29), off-road driving, mining, and hiking;\\u000a and, briefly, wildfire (for extensive discussion, see Chap. 28). Studies

J. Belnap; D. Eldridge

42

Vermicompost as a Biological Soil Amendment  

Microsoft Academic Search

\\u000a The viability of using earthworms as a treatment technique for the biological wastes producing organic fertilizers. A variety\\u000a of organic solid wastes, domestic and agro-industrial, can be vermicomposted. Vermicomposting technology involves harnessing\\u000a earthworms as versatile natural bioreactors, which play a vital role in decomposition of organic matter, maintaining soil\\u000a fertility, and bringing out efficient natural recycling and enhanced plants’ growth.

J. Tajbakhsh; E. Mohammadi Goltapeh; Ajit Varma

43

Biological Soil Crusts of the Middle East  

Microsoft Academic Search

\\u000a Large parts of the Middle Eastern countries (Egypt, Israel, Lebanon, Syria, Jordan, Iraq, Saudi Arabia, Kuwait) are arid and\\u000a semiarid regions, and thus are characterized by limited higher plant cover. These areas are often densely covered by communities\\u000a of cyanobacteria, green algae, fungi, lichens, and mosses which form typical biological soil crusts. The information available\\u000a on these crusts for the

M. Galun; J. Garty

44

Nocardiopsis and Saccharothrix genera in Saharan soils in Algeria: Isolation, biological activities and partial characterization of antibiotics  

Microsoft Academic Search

Twenty-five soil samples were collected in the Algerian Sahara and analyzed to isolate rare actinomycetes. Eighty-six isolates with the same Nocardiopsis or Saccharothrix morphology were isolated on humic–vitamin B agar medium using dilution techniques and several antibiotics as selective agents. Certain of these antibiotics seemed to be very selective for some phenotypes. Morphological and chemotaxonomic characteristics led to identifying 54

Abdelghani Zitouni; Hadjira Boudjella; Lynda Lamari; Boubekeur Badji; Florence Mathieu; Ahmed Lebrihi; Nasserdine Sabaou

2005-01-01

45

Mutual relationships between soils and biological carrier systems.  

PubMed

Improved viability and antagonistic activity of biocontrol agents during soil inoculation is of crucial importance to their effective application. The chitinolytic bacterium Serratia marcescens was used as a model organism to study the efficacy of freeze-dried alginate beads (in comparison to their non-dried counterparts) as possible carriers for immobilized biocontrol agents. The release of bacteria and chitinolytic enzyme from alginate beads, before and during their application in soil, was examined, and the beads' physical properties characterized. Dispersal of the alginate bead-entrapped S. marcescens in the soil resulted in high soil cell densities throughout the 35 days of the experiment. Chitin inclusion in the beads resulted in significantly higher chitinolytic activity of S. marcescens, increased dry-bead porosity and decreased stiffness. Rehydration of the dried beads (after immersion in soil) resulted in a sixfold increase in weight due to water absorption. No significant differences were found in bacterial count inside the non-dried (gel) versus dried beads. However, higher cell densities and chitinase activity were detected in soil containing dried beads with chitin than in that containing their non-dried counterparts. The biological performance of S. marcescens was examined in the greenhouse: a free cell suspension reduced bean (Phaseolus vulgaris L.) disease by 10%, while immobilized bacteria found in the dried, chitin-containing beads reduced disease by 60%. PMID:15962339

Zohar-Perez, C; Chet, I; Nussinovitch, A

2005-10-01

46

Biological residues define the ice nucleation properties of soil dust  

NASA Astrophysics Data System (ADS)

Soil dust is a major driver of ice nucleation in clouds leading to precipitation. It consists largely of mineral particles with a small fraction of organic matter constituted mainly of remains of micro-organisms that participated in degrading plant debris before their own decay. Some micro-organisms have been shown to be much better ice nuclei than the most efficient soil mineral. Yet, current aerosol schemes in global climate models do not consider a difference between soil dust and mineral dust in terms of ice nucleation activity. Here, we show that particles from the clay and silt size fraction of four different soils naturally associated with 0.7 to 11.8 % organic carbon (w/w) can have up to four orders of magnitude more ice nucleation sites per unit mass active in the immersion freezing mode at -12 °C than montmorillonite, the nucleation properties of which are often used to represent those of mineral dusts in modelling studies. Most of this activity was lost after heat treatment. Removal of biological residues reduced ice nucleation activity to, or below that of montmorillonite. Desert soils, inherently low in organic content, are a large natural source of dust in the atmosphere. In contrast, agricultural land use is concentrated on fertile soils with much larger organic matter contents than found in deserts. It is currently estimated that the contribution of agricultural soils to the global dust burden is less than 20 %. Yet, these disturbed soils can contribute ice nuclei to the atmosphere of a very different and much more potent kind than mineral dusts.

Conen, F.; Morris, C. E.; Leifeld, J.; Yakutin, M. V.; Alewell, C.

2011-09-01

47

[Biological soil crust nitrogenase activity and its responses to hydro-thermic factors in different erosion regions on the Loess Plateau, China].  

PubMed

Based on field survey, the biological soil crusts at their stable development stage were collected from the water erosion region, water-wind erosion region, and wind erosion region on the Loess Plateau, aimed to study the effects of the variations of moisture and temperature on the crusts nitrogenase activity (NA). The NA of the crusts in the erosion regions decreased in the order of water erosion region (127.7 micromol x m(-2) x h(-1)) > water-wind erosion region (34.6 micromol x m(-2) x h(-1)) > wind erosion region (6.0 micromol x m(-2) x h(-1)), and the optimal temperature for the crust nitrogen fixation was 35 degrees C, 25 degrees C, and 15 degrees C, respectively. At the optimal temperature and 100% -40% field water-holding capacity, the NA of the crusts from the water erosion and water-wind erosion regions had no significant difference. The NA of the crusts from the wind erosion region was more sensitive to the variation of moisture, showing a dramatic decline when the moisture decreased to 80% field water-holding capacity, and totally lost when the moisture decreased to 20% field water-holding capacity. The differences in the NA of the crusts from the three erosion regions and the responses of the NA to the variations of moisture and temperature were likely associated with the climate, environment, and the crust species composition. PMID:24175513

Ming, Jiao; Zhao, Yun-Ge; Xu, Ming-Xiang; Yang, Li-Na; Wang, Ai-Guo

2013-07-01

48

METHOD FOR SCALING BIOLOGICAL RESPONSE OF SOIL MICROCOSMS  

EPA Science Inventory

An extensive series of laboratory experiments was conducted in soil microcosms to study the respiratory response of microorganisms to toxicant amendments within different types of soils. Our analysis of test results demonstrates that coupled biological and environmental factors w...

49

Active Synthetic Soil.  

National Technical Information Service (NTIS)

A synthetic soil/fertilizer for horticultural application having all the agronutrients essential for plant growth is disclosed. The soil comprises a synthetic apatite fertilizer having sulfur, magnesium, and micronutrients dispersed in a calcium phosphate...

D. W. Ming D. L. Henninger E. R. Allen D. C. Golden

1994-01-01

50

Evaluation of Biological and Enzymatic Activity of Soil in a Tropical Dry Forest: Desierto de la Tatacoa (Colombia) with Potential in Mars Terraforming and Other Similar Planets  

NASA Astrophysics Data System (ADS)

Desierto de la Tatacoa has been determined to be a tropical dry forest bioma, which is located at 3° 13" N 75° 13" W. It has a hot thermal floor with 440 msnm of altitude; it has a daily average of 28° C, and a maximum of 40° C, Its annual rainfall total can be upwards of 1250 mm. Its solar sheen has a daily average of 5.8 hours and its relative humidity is between 60% and 65%. Therefore, the life forms presents are very scant, and in certain places, almost void. It was realized a completely random sampling of soil from its surface down to 6 inches deep, of zones without vegetation and with soils highly loaded by oxides of iron in order to determine the number of microorganisms per gram and its subsequent identification. It was measured the soil basal respiration. Besides, it was determined enzymatic activity (catalase, dehydrogenase, phosphatase and urease). Starting with the obtained results, it is developes an alternative towards the study of soil genesis in Mars in particular, and recommendations for same process in other planets. Although the information found in the experiments already realized in Martian soil they demonstrate that doesnt exist any enzymatic activity, the knowledge of the same topic in the soil is proposed as an alternative to problems like carbonic fixing of the dense Martian atmosphere of CO2, the degradation of inorganic compounds amongst other in order to prepare the substratum for later colonization by some life form.

Moreno Moreno, A. N.

2009-12-01

51

Climatic influences on active fractions of soil organic matter  

Microsoft Academic Search

Biologically active fractions of soil organic matter are important in understanding decomposition potential of organic materials, nutrient cycling dynamics, and biophysical manipulation of soil structure. We evaluated the quantitative relationships among potential C and net N mineralization, soil microbial biomass C (SMBC), and soil organic C (SOC) under four contrasting climatic conditions. Mean SOC values were 28±11mgg?1 (n=24) in a

A. J. Franzluebbers; R. L. Haney; C. W. Honeycutt; M. A. Arshad; H. H. Schomberg; F. M. Hons

2001-01-01

52

Untangling the biological contributions to soil stability in semiarid shrublands  

Microsoft Academic Search

Communities of plants, biological soil crusts (BSCs), and arbuscular mycorrhizal (AM) fungi are known to influence soil stability individually, but their relative contributions, interactions, and combined effects are not well understood, particularly in arid and semiarid ecosystems. In a landscape-scale field study we quantified plant, BSC, and AM fungal communities at 216 locations along a gradient of soil stability levels

V. Bala Chaudhary; Matthew A. Bowker; Thomas E. O'Dell; James B. Grace; Andrea E. Redman; Matthias C. Rillig; Nancy C. Johnson

2009-01-01

53

BIOGEOGRAPHY AND BIODIVERSITY OF BIOLOGICAL SOIL CRUSTS ACROSS QUEENSLAND  

Microsoft Academic Search

Recent field research has established that biological soil crust communities (cyanobacteria, lichens, liverworts and mosses) are widespread across the rangelands of Queensland. Our survey has covered many national parks and reserves or private properties where necessary, to take in changes in rainfall gradients, vegetation communities and soils. We document for the first time, well-established and extensive cyanobacteria-dominated soil crusts occurring

Wendy J. Williams; Burkhard Büdel; Colin Driscoll

54

Biological Features of the Soil: Advanced Crop and Soil Science. A Course of Study.  

ERIC Educational Resources Information Center

The course of study represents the third of six modules in advanced crop and soil science and introduces the agriculture student to biological features of soil. Upon completing the two day lesson, the student will: (1) realize the vast amount of life present in the soil, (2) be able to list representative animal and plant life in the soil by size,…

Miller, Larry E.

55

RESPONSE OF SOIL MICROBIOLOGICAL ACTIVITIES TO CD, PB, AND ZN SALT AMENDMENTS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Heavy metal pollution of soil has been recognized as a major factor impeding soil microbial processes. We studied responses of the soil biological activities to metal stress simulated by soil amendment with Zn, Pb and Cd chlorides. The amounts of heavy metal salts added to five metal polluted soils ...

56

Biological and biochemical soil indicators: monitoring tools of different agricultural managements  

NASA Astrophysics Data System (ADS)

The intensive agricultural managements, increased in the last twenty years, have resulted in a decrease in fertility of soils, representing a serious threat to agricultural productivity due to both the increase in production cost, mainly for intensive use of mineral fertilizers, and the loss of the quality of crops themselves. Organic matter content is closely related to the soil fertility and its progressive reduction in cultivates soils, without a satisfactory recovery, could make agriculture untenable, resulting in a high detrimental effect on environment. But an appropriate soil management practices can improve soil quality by utilizing organic amendments as alternative to mineral fertilizers to increase soil quality and plant growth. In this context, demand of suitable indicators, whose are able to assess the impact of different agricultural managements on soil quality, has increased. It has shown that soil biological and biochemical properties are able to respond to small changes in soil conditions, thus providing information on subtle alterations in soil quality. Aim of this study was to evaluate the use of soil biological and biochemical properties as fertility indicators in agricultural soils under different agricultural managements, sited in Campania Region (Southern Italy). After a preliminary monitoring phase of soil fertility on different farms sited in five agricultural areas of Campania Region, we have selected two farms in two different study areas to assess the effect on soil quality of different organic amendments. In particular, a compost from municipal solid waste and wood from scraps of poplars pruning were supplied in different doses and ratios. Soil samplings after one month from the amendment addition and then every 4 months until a year were carried out. All collected soil samples were characterized by main physical, chemical, biochemical and biological properties. In general, the use of different organic amendments showed a positive effect on fertility of both soils under intensive farming. In general, all enzymatic activities and organic carbon content increased after 1 month, and they were still higher after 4 months from amendment application. Microbial biomass and soil potential activity (respiration) showed significantly higher values in soils added with organic amendments, for both farms and samplings, with more marked effects on respiration in the first sampling. In conclusion results showed, in general, a quick response as indicators of the assayed biological and biochemical soil properties and a good recovery in fertility of the studied agricultural soils. The project was founded by CCIIAA of Salerno

Scotti, Riccardo; Sultana, Salma; Scelza, Rosalia; Marzaioli, Rossana; D'Ascoli, Rosaria; Rao, Maria A.

2010-05-01

57

Impact of biological soil crusts and desert plants on soil microfaunal community composition  

Microsoft Academic Search

Carbon and nitrogen are supplied by a variety of sources in the desert food web; both vascular and non-vascular plants and cyanobacteria supply carbon, and cyanobacteria and plant-associated rhizosphere bacteria are sources of biological nitrogen fixation. The objective of this study was to compare the relative influence of vascular plants and biological soil crusts on desert soil nematode and protozoan

Brian J. Darby; Deborah A. Neher; Jayne Belnap

2009-01-01

58

Impact of an intensive management on soil biochemical and biological properties in an agricultural soil of Southern Italy  

NASA Astrophysics Data System (ADS)

An intensive management of agricultural soils is widely carried out to increase vegetation productivity. Nevertheless, the large use of machineries, chemical fertilizers and pesticides can often cause, in time, a substantial decline in soil fertility by affecting soil physical and chemical properties and, in turn, growth and activity of soil microbial community. In fact, alteration in soil structure, nutrient losses and, in particular, changes in quality and quantity of soil organic matter are some of the principal soil degradation processes deriving from an intensive agricultural management that can affect, in different ways, soil biochemical and biological properties. The aim of this research was to assess the impact of intensive management on agricultural soils by measuring soil physical, chemical and biochemical/biological properties. The use of appropriate indicators as quantitative tools could allow to assess soil quality. Moreover, although soil physical and chemical properties have received great attention, soil biochemical/biological properties, such as enzyme activities and microbial biomass, functionally related properties involved in the nutrient cycles, can be considered as sensitive indicators of soil quality and health changes because, they show a faster turn over compared to soil organic matter. Our attention was focused on the Plane of Sele river (Campania region, Italy), an area characterized by an intensive agriculture and greenhouse cultures. Twenty-five farms were chosen, with the aid of regional soil map, in order to get soils with different physical and chemical properties. As common trait, the selected farms, all with greenhouse cultures, used no organic amendments but only mineral compounds to fertilize soils. Moreover, to better understand the impact of intensive agricultural practices on soil of each farm, control soils from orchards or uncultivated plots were chosen. In each farm soil samples were collected in three different plots within a greenhouse or within a field, for control soils. Every sample was formed by 5 sub-samples collected in 5 different points following a W scheme in the plot. All samples, sieved at 2 mm mesh, were stored at 4 °C and characterized by analysing the following soil physical and chemical, properties: soil texture, bulk density, water content, water holding capacity, pH, cation exchange capacity, organic carbon, total nitrogen, phosphorus, potassium, sodium, lime, and electrical conductivity were determined. Moreover the activity of dehydrogenase, beta-glucosidase, urease, phosphatase, and arilsulphatase, the enzymes involved in the biogeochemical cycles of carbon, nitrogen, phosphorous and sulphur, respectively, as well as microbial biomass C were measured. Results of this study seem to indicate that a great variability exists among the farms. A clear evidence is that the control samples, not subjected to intensive farming, always showed better values of chemical properties and higher values of enzymatic activity and microbial biomass to indicate a negative effect of intensive agriculture practices on soil quality and fertility in studied areas. Data confirm that enzymatic activities and microbial biomass can be considered valid and sensitive indicators of soil quality.

Scotti, R.; D'Ascoli, R.; Rao, M. A.; Marzaioli, R.; Rutigliano, F. A.; Gianfreda, L.

2009-04-01

59

Application of Two Organic Amendments on Soil Restoration: Effects on the Soil Biological Properties  

Microsoft Academic Search

One method for recovering degraded soils in semiarid regions is to add organic matter to improve soil characteristics, thereby enhancing biogeochemical nutrient cycling. In this paper, we studied the changes in soil biological properties as a result of adding a crushed cotton gin compost (CCGC) and a poultry manure (PM) for 4 yr to restore a Xerollic Calciorthid located near

M. Tejada; M. T. Hernandez; C. Garcia

2006-01-01

60

Soil nematode communities are ecologically more mature beneath late- than early-successional stage biological soil crusts  

Microsoft Academic Search

Biological soil crusts are key mediators of carbon and nitrogen inputs for arid land soils and often represent a dominant portion of the soil surface cover in arid lands. Free-living soil nematode communities reflect their environment and have been used as biological indicators of soil condition. In this study, we test the hypothesis that nematode communities are successionally more mature

Brian J. Darby; Deborah A. Neher; Jayne Belnap

2007-01-01

61

Effects of biological weathering on mine soil genesis and fertility  

SciTech Connect

Strip mine spoils derived from overburden rocks of the Pennsylvanian Wise Formation in Buchanan County, Virginia, commonly contain 40% less than 2 mm sized soil material. The physical and chemical properties of these soil materials are related to their rock origin. The soil materials are alkaline due to the presence of carbonates. The principal source of P in the soil materials is apatite, and the principal source of K is mica. A greenhouse experiment was conducted to determine the short-term plant availability of P and K in these soil materials. Growth of sericea lespedeza over a 60-day period was found to be limited by P availability and not to be limited by K availability. Uptake of P by servicea lespedeza from P fertilized and unfertilized soil materials was found to be correlated with NaHCO3 extractable P from pots which received the same fertilizer treatments but did not contain plants. The correlations obtained were soil material specific. A separate greenhouse experiment was conducted in order to identify the effects of biological weathering on soil material properties. Sericea lespedeza and black locust were grown on unfertilized brown sandstone soil material for one year. Soil material pH was uniformly reduced by plant action regardless of proximity to roots. The P present in the soil material, however, was not uniformly depleted. Over half of the P removed from the soil material by sericea lespedeza and black locust was P which cannot be extracted using dilute HCl-H2SO4, but can be extracted using concentrated HCl. The results of the two experiments indicate that the plant availability of P and K in the soil materials is influenced by biological weathering. Acidification of the soil material increases the availability of P present in apatite particles. Uptake of K insures that the soil solution is constantly replenished with K from mica and that mica is transformed into vermiculite.

Everett, C.J.

1981-01-01

62

[Biologically active food additives].  

PubMed

More than half out of 40 projects for the medical science development by the year of 2000 have been connected with the bio-active edible additives that are called "the food of XXI century", non-pharmacological means for many diseases. Most of these additives--nutricevtics and parapharmacevtics--are intended for the enrichment of food rations for the sick or healthy people. The ecologicaly safest and most effective are combined domestic adaptogens with immuno-modulating and antioxidating action that give anabolic and stimulating effect,--"leveton", "phytoton" and "adapton". The MKTs-229 tablets are residue discharge means. For atherosclerosis and general adiposis they recommend "tsar tablets" and "aiconol (ikhtien)"--on the base of cod-liver oil or "splat" made out of seaweed (algae). All these preparations have been clinically tested and received hygiene certificates from the Institute of Dietology of the Russian Academy of Medical Science. PMID:9752776

Velichko, M A; Shevchenko, V P

1998-07-01

63

A new index for mapping lichen-dominated biological soil crusts in desert areas  

Microsoft Academic Search

Tracking the presence, distribution and disappearance of biological soil crusts is important for ecosystem management of desert regions and provides highly valuable information on desertification and climate change studies in arid environments. Based on the analysis of the spectral features of biological soil crusts, we propose a new biological soil crust index (BSCI) for biological soil crusts mapping. Using both

Jin Chen; Ming Yuan Zhang; Le Wang; Hiroto Shimazaki; Masayuki Tamura

2005-01-01

64

Effects of transgenic Bt cotton on soil fertility and biology under field conditions in subtropical inceptisol.  

PubMed

Although there is large-scale adoption of Bt cotton by the farmers because of immediate financial gain, there is concern that Bt crops release Bt toxins into the soil environment which reduces soil chemical and biological activities. However, the majorities of such studies were mainly performed under pot experiments, relatively little research has examined the direct and indirect effects of associated cover crop of peanut with fertilization by combined application of organic and inorganic sources of nitrogen under field conditions. We compared soil chemical and biological parameters of Bt cotton with pure crop of peanut to arrive on a valid conclusion. Significantly higher dehydrogenase enzyme activity and KMnO(4)-N content of soil were observed in Bt cotton with cover crop of peanut over pure Bt cotton followed by pure peanut at all the crop growth stages. However, higher microbial population was maintained by pure peanut over intercropped Bt cotton, but these differences were related to the presence of high amount of KMnO(4)-N content of soil. By growing cover crop of peanut between Bt cotton rows, bacteria, fungi, and actinomycetes population increased by 60%, 14%, and 10%, respectively, over Bt cotton alone. Bt cotton fertilized by combined application of urea and farm yard manure (FYM) maintained higher dehydrogenase enzyme activity, KMnO(4)-N content of soil and microbial population over urea alone. Significant positive correlations were observed for dry matter accumulation, dehydrogenase enzyme activity, KMnO(4)-N content, and microbial population of soil of Bt cotton, which indicates no harmful effects of Bt cotton on soil biological parameters and associated cover crop. Our results suggest that inclusion of cover crop of peanut and FYM in Bt cotton enhanced soil chemical and biological parameters which can mask any negative effect of the Bt toxin on microbial activity and thus on enzymatic activities. PMID:22350447

Singh, Raman Jeet; Ahlawat, I P S; Singh, Surender

2012-02-21

65

The influence of carbonates in parent rocks on the biological properties of mountain soils of the Northwest Caucasus region  

NASA Astrophysics Data System (ADS)

The biological activity of different subtypes of soddy-calcareous soils (rendzinas) of the Northwest Caucasus region was studied. In the Novorossiisk-Abrau-Dyurso region (dry subtropics), typical soddy-calcareous soils with the high content of carbonates predominate; in the more humid conditions of the Lagonaki Plateau (Republic of Adygeya), leached soddy-calcareous soils carbonate-free down to the parent rock are spread. The number of microarthropods, the populations of fungi and bacteria, and the enzyme activity (catalase, dehydrogenase, and invertase) testify that the biological activity of these soils significantly differs. In the typical soddy-calcareous soils of the dry subtropics, the content of carbonates does not affect the characteristics mentioned; in the more humid conditions of the West Caucasus region, the presence of carbonates in the parent rocks intensifies the biological activity of the soddy-calcareous soils.

Kazeev, K. Sh.; Kutrovskii, M. A.; Dadenko, E. V.; Vezdeneeva, L. S.; Kolesnikov, S. I.; Val'kov, V. F.

2012-03-01

66

Bioaugmentation, Biostimulation, and Biocontrol in Soil Biology  

Microsoft Academic Search

\\u000a Soils sustain an immense diversity of prokaryotic and eukaryotic organisms. Microbial functions in ecosystems are as diverse\\u000a as the microbes themselves. Differences in microbial community structures reflect the abilities of microorganisms to respond\\u000a to specific environmental factors and substrates. Microbes adapt to these microhabitats and live together in consortia, interacting\\u000a with each other and with other parts of the soil

Ajay Singh; Nagina Parmar; Ramesh C. Kuhad; Owen P. Ward

67

ALTERNATIVE BIOLOGICAL AMENDMENTS: EFFECTS ON SOIL BIOLOGY AND SOILBORNE DISEASES  

Technology Transfer Automated Retrieval System (TEKTRAN)

A variety of biological amendments, including commercial biocontrol organisms, microbial inoculants, and biostimulants, were evaluated in greenhouse and field tests for efficacy in controlling soilborne diseases of potato. The commercial biocontrol agents Bacillus subtilis (Bsub), Burkhoderia cepaci...

68

Biological studies of martian soil analogues  

NASA Astrophysics Data System (ADS)

Results of the study of the influence of Martian soil analogues, both as described by American scientists and as prepared by us, and of hydrogen peroxide on the viability of microorganisms are presented. The experiments were carried out using mixtures of soil analogues with desert soil and black earth (chernozem) samples, and pure cultures of microorganism. Microorganisms capable of withstanding a concentration of hydrogen peroxide in the medium as high as 1.5-2.0% were isolated. None of the 40 strains of microorganisms studied, all belonging to different systematic and physiological groups, exhibited growth inhibition on solid media in the presence of Martian soil analogues. In view of the fact that Martian soil cannot contain microorganisms in great quantities, we suggest using electroadsorption for their concentration, to make detection reliable. A device was designed for this purpose, using the principle of electroadsorption on a polarisable carrier (sterile cotton wool or cheesecloth). The concentrated suspension of microorganisms thus obtained was then characterized by various physicochemical methods.

Imshenetsky, A. A.; Murzakov, B. G.; Evdokimova, M. D.; Dorofeyeva, I. K.

69

Assessment of soil tolerance toward contamination with black oil in the south of Russia on the basis of soil biological indices: A model experiment  

NASA Astrophysics Data System (ADS)

The effect of soil contamination with black oil added in amounts of 0.1, 0.5, 1.0, 2.5, 5, 10, 25, and 50% of the soil mass on the biological properties of ordinary and leached vertic chernozems, brown forest soils, and gray sands in the south of Russia was studied in a model laboratory experiment. It was shown that the soil contamination causes a drop in the catalase and dehydrogenase activities, the cellulolytic capacity, the number of Azotobacter bacteria, and the characteristics of the plant germination. The ordinary and vertic chernozems were more tolerant toward the contamination than the gray sands and brown forest soils. The changes in the biological soil properties in dependence on the degree of the soil contamination differed considerably for the soils with different properties (the chernozems, brown forest soil, and gray sands) and were similar for the soils with similar properties (the ordinary and vertic chernozems). One soil (the brown forest soil) could be more tolerant toward the contamination than another soil (the gray sands) at a given concentration of black oil (<2.5%) and less tolerant at another concentration of black oil (>2.5%). The ecologically safe levels of the soil contamination with black oil do not exceed 0.7% in the ordinary chernozems, 0.3% in the compact chernozems, 0.1% in the brown forest soils, and 0.06% in the gray sands.

Kolesnikov, S. I.; Gaivoronskii, V. G.; Rotina, E. N.; Kazeev, K. Sh.; Val'Kov, V. F.

2010-08-01

70

Diverse biological activities of dandelion.  

PubMed

Dandelion (Taraxacum officinale Weber) is a member of the Asteraceae (Compositae) family, native to Europe but widely distributed in the warmer temperate zones of the Northern Hemisphere. Dandelion and its parts are habitually consumed as plant foods in several areas of the world, where they are also employed in phytotherapy. Indeed, dandelion contains a wide array of phytochemicals whose biological activities are actively being explored in various areas of human health. In particular, emerging evidence suggests that dandelion and its constituents have antioxidant and anti-inflammatory activities that result in diverse biological effects. The present review provides a comprehensive analysis of the constituents of dandelion, an assessment of the pharmacological properties of dandelion, and a description of relevant studies that support the use of dandelion as a medicinal plant. PMID:22946853

González-Castejón, Marta; Visioli, Francesco; Rodriguez-Casado, Arantxa

2012-08-17

71

Impact of biological soil crusts and desert plants on soil microfaunal community composition  

Microsoft Academic Search

Carbon and nitrogen are supplied by a variety of sources in the desert food web; both vascular and non-vascular plants and\\u000a cyanobacteria supply carbon, and cyanobacteria and plant-associated rhizosphere bacteria are sources of biological nitrogen\\u000a fixation. The objective of this study was to compare the relative influence of vascular plants and biological soil crusts\\u000a on desert soil nematode and protozoan

Brian J. Darby; Deborah A. Neher; Jayne Belnap

2010-01-01

72

Metal Pollution in Forest Soils. Biological Effects.  

National Technical Information Service (NTIS)

Results of five-years' research on the effects of copper-zinc pollution on soil organisms and processes are presented. The area studied was the coniferous woodland surrounding the Gusum brass mill in the province of Oestergoetland, southeast Sweden. The a...

G. Tyler G. Bengtsson L. Folkeson T. Gunnarson S. Rundren

1984-01-01

73

Soil Biology in Traditional Agroforestry Systems of the Indian Desert  

Microsoft Academic Search

\\u000a Traditional arid and semi-arid agroforestry systems serve as models for the ‘protective-productive’ rehabilitation strategies\\u000a of agrarians. The nature of the organic materials present and their decomposition governs nutrient availability in soil systems.\\u000a Indian desert vegetation has various non-fodder plants in and around farms that can well be used, along with diverse microbes,\\u000a for improving soil biological fertility. The higher percentage

S. Sundaramoorthy; Santosh Kumar Mehar; Manohar Singh Suthar

74

Near infrared spectroscopy of forest soils to determine chemical and biological properties related to soil sustainability  

Microsoft Academic Search

Sustainability related soil changes due to site disturbance during forest harvesting need to be assessed. Near infrared spectroscopy (NIRS) may be useful for assessing large numbers of samples covering a landscape and dispersed over a long time span. This paper presents an evaluation of the use of NIRS to examine a number of chemical and biological soil properties. One hundred

B Ludwig; P. K Khanna; J Bauhus; P Hopmans

2002-01-01

75

Evaluation of the efficiency of a phytostabilization process with biological indicators of soil health.  

PubMed

A phytostabilization process that combined the addition of a synthetic (Calcinit + urea + PK14% + calcium carbonate) or organic (cow slurry) amendment with Lolium perenne L. growth was used to remediate a mine soil moderately contaminated with Zn, Pb, and Cd. The reduced toxicity caused by both amendments allowed the establishment of a healthy L. perenne vegetation cover that had a positive influence on soil properties, increasing the biomass, activity, and functional diversity of the soil microbial community. The beneficial effects of phytostabilization on soil properties were more accentuated in organically amended than in synthetically amended soils. Root-to-shoot translocation factors were smaller in amended versus control plants, indicating a reduction in the risk of metals entering the food chain through phytostabilization. The sensitivity, rapid response, and integrative character of biological indicators of soil health make them valuable tools for assessing the efficiency of metal phytostabilization processes. PMID:19704147

Epelde, Lur; Becerril, José M; Mijangos, Iker; Garbisu, Carlos

2009-08-24

76

On the potential of biological treatment for arsenic contaminated soils and groundwater  

Microsoft Academic Search

Bioremediation of arsenic contaminated soils and groundwater shows a great potential for future development due to its environmental compatibility and possible cost-effectiveness. It relies on microbial activity to remove, mobilize, and contain arsenic through sorption, biomethylation–demethylation, complexation, coprecipitation, and oxidation–reduction processes. This paper gives an evaluation on the feasibility of using biological methods for the remediation of arsenic contaminated soils

Suiling Wang; Xiangyu Zhao

2009-01-01

77

Untangling the biological contributions to soil stability in semiarid shrublands.  

PubMed

Communities of plants, biological soil crusts (BSCs), and arbuscular mycorrhizal (AM) fungi are known to influence soil stability individually, but their relative contributions, interactions, and combined effects are not well understood, particularly in arid and semiarid ecosystems. In a landscape-scale field study we quantified plant, BSC, and AM fungal communities at 216 locations along a gradient of soil stability levels in southern Utah, USA. We used multivariate modeling to examine the relative influences of plants, BSCs, and AM fungi on surface and subsurface stability in a semiarid shrubland landscape. Models were found to be congruent with the data and explained 35% of the variation in surface stability and 54% of the variation in subsurface stability. The results support several tentative conclusions. While BSCs, plants, and AM fungi all contribute to surface stability, only plants and AM fungi contribute to subsurface stability. In both surface and subsurface models, the strongest contributions to soil stability are made by biological components of the system. Biological soil crust cover was found to have the strongest direct effect on surface soil stability (0.60; controlling for other factors). Surprisingly, AM fungi appeared to influence surface soil stability (0.37), even though they are not generally considered to exist in the top few millimeters of the soil. In the subsurface model, plant cover appeared to have the strongest direct influence on soil stability (0.42); in both models, results indicate that plant cover influences soil stability both directly (controlling for other factors) and indirectly through influences on other organisms. Soil organic matter was not found to have a direct contribution to surface or subsurface stability in this system. The relative influence of AM fungi on soil stability in these semiarid shrublands was similar to that reported for a mesic tallgrass prairie. Estimates of effects that BSCs, plants, and AM fungi have on soil stability in these models are used to suggest the relative amounts of resources that erosion control practitioners should devote to promoting these communities. This study highlights the need for system approaches in combating erosion, soil degradation, and arid-land desertification. PMID:19323176

Chaudhary, V Bala; Bowker, Matthew A; O'Dell, Thomas E; Grace, James B; Redman, Andrea E; Rillig, Matthias C; Johnson, Nancy C

2009-01-01

78

Biological and abiotic losses of polynuclear aromatic hydrocarbons (PAHs) from soils freshly amended with sewage sludge  

SciTech Connect

Sewage sludge containing typical indigenous concentrations of polynuclear aromatic hydrocarbons (PAHs) was applied to several different soils in glass microcosms. Biologically active and sterilized soils were monitored for PAH content over a period of approximately 205 d. Agricultural soils with and without previous exposure to sewage sludge were tested, together with a forest soil and a soil from a major roadside. Loss of PAHs from a soil spike with a PAH standard solution was also investigated. Results indicate the PAH compounds with less than four benzene rings are susceptible to abiotic loss processes. However, losses by these mechanisms were insignificant for compounds with four or more benzene rings. Half-lives for the sludge-applied PAHs were derived and indicated a strong dependence of persistence on chemical structure. Half-lives for phenanthrene and benzo[ghi]perylene were between 83 and 193 d and 282 and 535 d, respectively. Mean half-lives correlate directly with log K[sub ow] and inversely with log water solubility. Behavior of PAHs was different in each soil, probably due to different soil characteristics and history of PAH exposure. The soil spiked with PAHs provided the lowest half-life values for most PAH compounds, suggesting a higher susceptibility of spiked PAHs to both abiotic and biological degradation.

Wild, S.R.; Jones, K.C. (Lancaster Univ. (United Kingdom))

1993-01-01

79

Biological soil disinfestation : a safe and effective approach for controlling soilborne pests and diseases  

Microsoft Academic Search

Biological soil disinfestation (bsd) is an environmentally friendly method to disinfest the soil from soilborne fungi and nematodes. With biological soil disinfestation a green manure crop (40 tonnes per ha) or other green biomass is homogeneously incorporated into the soil layer that has to be disinfested. Then the field is lightly compacted and irrigated. Subsequently, the soil is covered with

J. G. Lamers; P. J. Wanten; W. J. Blok

2004-01-01

80

Effects of Cd and Pb on soil microbial community structure and activities  

Microsoft Academic Search

Background, aim, and scope  Soil contamination with heavy metals occurs as a result of both anthropogenic and natural activities. Heavy metals could have\\u000a long-term hazardous impacts on the health of soil ecosystems and adverse influences on soil biological processes. Soil enzymatic\\u000a activities are recognized as sensors towards any natural and anthropogenic disturbance occurring in the soil ecosystem. Similarly,\\u000a microbial biomass carbon

Sardar Khan; Abd El-Latif Hesham; Min Qiao; Shafiqur Rehman; Ji-Zheng He

2010-01-01

81

Cropping Systems Management, Soil Microbial Communities, and Soil Biological Fertility  

Microsoft Academic Search

\\u000a Consumers are demanding more organic products, in part because of concerns over environmental issues in conventional agriculture.\\u000a Modern, high-input agriculture can cause groundwater contamination, soil erosion, and eutrophication of surface waters. It\\u000a may be possible to enhance natural nutrient cycling and reduce our dependence on inorganic fertilizers in cropping systems.\\u000a To do so, we have to manage our cropping systems

Alison G. Nelson; Dean Spaner

82

Diversity and Activity of Denitrifiers of Chilean Arid Soil Ecosystems  

PubMed Central

The Chilean sclerophyllous matorral is a Mediterranean semiarid ecosystem affected by erosion, with low soil fertility, and limited by nitrogen. However, limitation of resources is even more severe for desert soils such as from the Atacama Desert, one of the most extreme arid deserts on Earth. Topsoil organic matter, nitrogen and moisture content were significantly higher in the semiarid soil compared to the desert soil. Although the most significant loss of biologically preferred nitrogen from terrestrial ecosystems occurs via denitrification, virtually nothing is known on the activity and composition of denitrifier communities thriving in arid soils. In this study we explored denitrifier communities from two soils with profoundly distinct edaphic factors. While denitrification activity in the desert soil was below detection limit, the semiarid soil sustained denitrification activity. To elucidate the genetic potential of the soils to sustain denitrification processes we performed community analysis of denitrifiers based on nitrite reductase (nirK and nirS) genes as functional marker genes for this physiological group. Presence of nirK-type denitrifiers in both soils was demonstrated but failure to amplify nirS from the desert soil suggests very low abundance of nirS-type denitrifiers shedding light on the lack of denitrification activity. Phylogenetic analysis showed a very low diversity of nirK with only three distinct genotypes in the desert soil which conditions presumably exert a high selection pressure. While nirK diversity was also limited to only few, albeit distinct genotypes, the semiarid matorral soil showed a surprisingly broad genetic variability of the nirS gene. The Chilean matorral is a shrub land plant community which form vegetational patches stabilizing the soil and increasing its nitrogen and carbon content. These islands of fertility may sustain the development and activity of the overall microbial community and of denitrifiers in particular.

Orlando, Julieta; Caru, Margarita; Pommerenke, Bianca; Braker, Gesche

2012-01-01

83

Characterization of Soil Samples of Enzyme Activity  

ERIC Educational Resources Information Center

|Described are nine enzyme essays for distinguishing soil samples. Colorimetric methods are used to compare enzyme levels in soils from different sites. Each soil tested had its own spectrum of activity. Attention is drawn to applications of this technique in forensic science and in studies of soil fertility. (Author/AJ)|

Freeland, P. W.

1977-01-01

84

Microbial activity in acid and acidified forest soils  

SciTech Connect

Effect of soil acidity on microbial decomposition of organic matter, transformation of nitrogen, and soil chemical and biological properties of an acid forest soil were investigated. The rates of organic matter decomposition by natural acid soil and by pH-adjusted acid and neutral soils which were preincubated for 14 and 150 days were determined by monitoring CO/sub 2/ evolution. In the control (unamended) pH-adjusted acid soil, reductions in CO/sub 2/ production of 14% by 14-day preincubated samples and of 52% by 150-day samples were observed. In the oak-leaf-amended acidified soils, the CO/sub 2/ production by 14- and 150-day preincubated samples decreased by about 6 and 37%, respectively. Ammonification and nitrification in the natural acid and pH-adjusted acid soils were determined. In addition, the contribution of nitrate by heterotrophic microbial communities in natural acid and pH-adjusted acid soils was examined. Ammonia formation in the pH-adjusted acid soil was 50% less than in the natural acid soil. An increase in nitrate concentration in the pH-adjusted acid soil over that in the natural acid soil was observed. Increased rates of ammonification and nitrification were observed in the pH-adjusted neutral soil. Little autotrophic nitrifying activity was detected in natural acid and acidified forest soils and no detectable heterotrophic nitrification was observed. The data indicate that ammonification and nitrification are affected by an increase in soil acidity. These results suggest that further acidification of acid forest soils by addition of sulfuric acid or by acid precipitation may lead to significant reductions in the leaf litter decomposition, ammonification, and nitrification, and thus affect the nutrient recycling in the forest ecosystem.

Francis, A.J.; Olson, D.; Bernatsky, R.

1981-03-01

85

Effects of organic carbon sequestration strategies on soil enzymatic activities  

NASA Astrophysics Data System (ADS)

Greenhouse gases emissions can be counterbalanced with proper agronomical strategies aimed at sequestering carbon in soils. These strategies must be tested not only for their ability in reducing carbon dioxide emissions, but also for their impact on soil quality: enzymatic activities are related to main soil ecological quality, and can be used as early and sensitive indicators of alteration events. Three different strategies for soil carbon sequestration were studied: minimum tillage, protection of biodegradable organic fraction by compost amendment and oxidative polimerization of soil organic matter catalyzed by biometic porfirins. All strategies were compared with a traditional agricultural management based on tillage and mineral fertilization. Experiments were carried out in three Italian soils from different pedo-climatic regions located respectively in Piacenza, Turin and Naples and cultivated with maize or wheat. Soil samples were taken for three consecutive years after harvest and analyzed for their content in phosphates, ß-glucosidase, urease and invertase. An alteration index based on these enzymatic activities levels was applied as well. The biomimetic porfirin application didn't cause changes in enzymatic activities compared to the control at any treatment or location. Enzymatic activities were generally higher in the minimum tillage and compost treatment, while differences between location and date of samplings were limited. Application of the soil alteration index based on enzymatic activities showed that soils treated with compost or subjected to minimum tillage generally have a higher biological quality. The work confirms the environmental sustainability of the carbon sequestering agronomical practices studied.

Puglisi, E.; Suciu, N.; Botteri, L.; Ferrari, T.; Coppolecchia, D.; Trevisan, M.; Piccolo, A.

2009-04-01

86

Assessing soil biological characteristics: a comparison of bulk soil community DNA, PLFA-, and Biolog™analyses  

Microsoft Academic Search

Soil microbiological analyses may serve as a means for assessing soil characteristics. Standard microbiological culture-techniques, however, leave over 90% of the microorganisms in the environment unaccounted for. Several more recently developed analytical techniques such as DNA, phospholipid fatty acid (PLFA), and community level substrate utilization (CLSU) fingerprints allow for more detailed analyses of soil microbial communities. We applied analyses of

F. Widmer; A. Fließbach; E. Laczkó; J. Schulze-Aurich; J. Zeyer

2001-01-01

87

Nontarget effects of bacterial biological control agents on soil Protozoa  

Microsoft Academic Search

Biological control agents (BCAs) have gained increasing interest as an alternative to chemical pesticides in agriculture. Before widespread environmental use, risk assessment of effects on target and non-target organisms are needed. However, the knowledge about the effect of BCAs on non-target soil Protozoa is insufficient to support thorough risk assessment. In this study we report on the effects of Pseudomonas

Karen Stevnbak Andersen; Anne Winding

2004-01-01

88

Causes and consequences of biological diversity in soil.  

PubMed

There is a vast diversity of organisms that live in the soil, and the activities of the total soil biota, together with the diverse forms and functions of plant roots, have critical roles in soil functioning. In this paper I discuss the likely determinants of soil diversity and also comment on recent studies that have explored whether or not there is a relationship between soil organism diversity and ecosystem function. There is little evidence to suggest that soil diversity is regulated in a predicable fashion by competition or disturbance; rather it is attributed to the nature of the soil environment, in that soil offers an extremely heterogeneous habitat, both spatially and temporally, proving unrivalled potential for niche partitioning, or resource or habitat specialisation, thereby enabling co-existence of species. Most evidence that is available suggests that there is no predictable relationship between diversity and function in soils, and that ecosystem properties are governed more by individual traits of dominant species, and by the extraordinary complexity of biotic interactions that occur between components of soil food webs. There is evidence of redundancy in soil communities with respect to soil functions, but the scale of effect of changes in soil diversity on process rates depends on which species are removed from the community and the degree to which remaining species can compensate. As in aboveground communities, therefore, it would appear that species traits and changes in species composition, and alterations in the nature of the many important species interactions that occur in soil, are likely to be the main biotic control of ecosystem function. In view of this, consideration of these important biotic interactions and their sensitivity to environmental change must be a key priority for future research. PMID:16351885

Bardgett, Richard D

2002-01-01

89

Environmental implications of herbicide resistance: soil biology and ecology  

Technology Transfer Automated Retrieval System (TEKTRAN)

Soil microbial community structure and activity are clearly linked to plant communities established in natural and agricultural ecosystems. A limited number of studies confirm that weeds alter their soil environment and select for specific microbial communities in the rhizosphere. Such rhizosphere m...

90

Natural soil electronic active device diode  

Microsoft Academic Search

In continuation to our published work (Kosta et al. 2003, 2004a, b) on biological electronic circuits and recently submitted research work Kosta et al. (2005a, b) on natural soil (earth) electronic circuits in this paper we present successful experimental studies which scientifically predicated and established a soil (earth) electronic diode possessing conventional diode characteristics. Experimental lay out, schematic diagrams, tables

S. P. Kosta; Y. P. Kosta; V. Patel; K. Patel; P. Patel; P. Doshi; C. Patel; R. Jain; M. Thaker; N. Upadhyay; K. Pandya; J. Macwan; A. Patel; H. Pujara; D. D. Mishra; S. Patel

2006-01-01

91

Reconciling apparent variability in effects of biochar amendment on soil enzyme activities by assay optimization  

Microsoft Academic Search

We studied the effects of a biochar made from fast pyrolysis of switchgrass on four soil enzymes (?-glucosidase, ?-N-acetylglucosaminidase, lipase, and leucine aminopeptidase) to determine if biochar would consistently modify soil biological activities. Thus, we conducted a series of enzyme assays on biochar-amended soils. Inconsistent results from enzyme assays of char-amended soils suggested that biochar had variable effects on soil

Vanessa L. Bailey; Sarah J. Fansler; Jeffrey L. Smith; Harvey Bolton

2011-01-01

92

The Environmental Effects of Conventional and Organic\\/Biological Farming systems. II. Soil Ecology, Soil Fertility and Nutrient Cycles  

Microsoft Academic Search

The inputs characteristic of conventional and organic\\/biological farming systems are examined, and their physical, chemical and biological impacts on the ecology and fertility of agricultural soils, and on nutrient cycles within these systems, are evaluated. Inorganic fertilisers applied in conventional systems may not preserve soil structure, can cause wide fluctuations in the pH and ion concentrations of the soil solution,

C. Arden-Clarke; R. D. Hodges

1988-01-01

93

Field Guide to Biological Soil Crusts of Western U.S. Drylands; Common Lichens and Bryophytes.  

National Technical Information Service (NTIS)

Biological soil crusts (BSCs) are an intimate association between soil particles and cyanobacteria, algae, microfungi, lichens, and bryophytes (in different proportions) which live within or on top of the uppermost millimeters of soil. These communities h...

J. Belnap M. Bowker R. Rosentreter

2007-01-01

94

Nitrification activity in New Zealand grassland soils  

Microsoft Academic Search

Initial Nitrification Activity (INA) was measured in 68 New Zealand grassland soil sampies (0–75 mm) using a 17-h laboratory perfusion technique to provide a measure of the nitrifying activity. Considerable variation (< 0.02–5.70 ?g N oxidised\\/g soil\\/h)was found between soils, yellow-brown loams having higher INA values than other soil groups. Variation of pH, % total N, % organic C, and

K. W. Steele; A. T. Wilson; W. M. H. Saunders

1980-01-01

95

Carbondioxide exchange of biological soil crusts compared to disturbed soil / sand in semi arid areas  

NASA Astrophysics Data System (ADS)

Sparse vegetation in semi arid and arid lands is associated with low productivity and minor contribution to biosphere-atmosphere exchange of greenhouse gases, on an area basis. Dryland ecosystems, however, cover large land areas that are continuously increasing. Two third of global population live in semi arid and arid regions and its direct impact contributes to the expansion of dryland ecosystems. Satellite images at the start of the wet season in natural dryland ecosystems clearly show significant photosynthetic activity at a time when most vascular plants are yet inactive or undeveloped, indicating a possibly neglected CO_2 sink. This can likely be assigned to the so-called biological soil crusts (BSC) that consist of poikilohydric microphytes such as cyanobacteria, lichens, green algae, and mosses, which can rapidly recover photosynthesis in response to the earliest water supply. Such non-vascular vegetation activities are an important feature of dryland ecosystems worldwide, often complementary to that of vascular plants. We report on the rates of CO_2 exchange of BSC as measured at two field sites in the northern Negev desert during six months during 2001/2002. Peak rates of net photosynthesis (1.5 - 2 ?mol m-2 s-1) were in the range observed in vascular plants, but periods with low or no activities were considerable. Rates of CO_2 exchange of BSC was always compared with that of bare soil / sand. This allowed both estimating net local land surface exchange, and assessing the influence of disturbance, mainly by uncontrolled land use, of the highly vulnerable BSC ecosystems. Simultaneous measurements of spectral reflectance properties of BSC in this study aim to allow calibration of airborne remote sensing for large-scale BSC activity studies.

Wilske, B.; Yakir, D.; Burgheimer, J.; Karnieli, A.; Zaady, E.; Kesselmeier, J.

2003-04-01

96

Reconciling apparent variability in effects of biochar amendment on soil enzyme activities by assay optimization  

Technology Transfer Automated Retrieval System (TEKTRAN)

We studied the effects of a biochar made from switchgrass on four soil enzymes (ß- glucosidase, ß-N-acetylglucosaminidase, lipase, and leucine aminopeptidase) to determine if biochar would consistently modify soil biological activities. Inconsistent results from enzyme assays of char-amended soils s...

97

Biological functioning of PAH-polluted and thermal desorption-treated soils assessed by fauna and microbial bioindicators.  

PubMed

A large number of soil bioindicators were used to assess biological diversity and activity in soil polluted with polycyclic aromatic hydrocarbons (PAHs) and the same soil after thermal desorption (TD) treatment. Abundance and biodiversity of bacteria, fungi, protozoa, nematodes and microarthropods, as well as functional parameters such as enzymatic activities and soil respiration, were assessed during a two year period of in situ monitoring. We investigated the influence of vegetation (spontaneous vegetation and Medicago sativa) and TD treatment on biological functioning. Multivariate analysis was performed to analyze the whole data set. A principal response curve (PRC) technique was used to evaluate the different treatments (various vegetation and contaminated vs. TD soil) contrasted with control (bare) soil over time. Our results indicated the value of using a number of complementary bioindicators, describing both diversity and functions, to assess the influence of vegetation on soil and discriminate polluted from thermal desorption (TD)-treated soil. Plants had an influence on the abundance and activity of all organisms examined in our study, favoring the whole trophic chain development. However, although TD-treated soil had a high abundance and diversity of microorganisms and fauna, enzymatic activities were weak because of the strong physical and chemical modifications of this soil. PMID:21392572

Cébron, Aurélie; Cortet, Jérôme; Criquet, Stéven; Biaz, Asmaa; Calvert, Virgile; Caupert, Cécile; Pernin, Céline; Leyval, Corinne

2011-03-21

98

[Effects of biological soil crust at different succession stages in hilly region of Loess Plateau on soil CO2 flux].  

PubMed

Biological soil crust (biocrust) is a compact complex layer of soil, which has photosynthetic activity and is one of the factors affecting the CO2flux of soil-atmosphere interface. In this paper, the soil CO, flux under the effects of biocrust at different succession stages on the re-vegetated grassland in the hilly region of Loess Plateau was measured by a modified LI-8100 automated CO, flux system. Under light condition, the soil CO2 flux under effects of cyanobacteria crust and moss crust was significantly decreased by 92% and 305%, respectively, as compared with the flux without the effects of the biocrusts. The decrement of the soil CO, flux by the biocrusts was related to the biocrusts components and their biomass. Under the effects of dark colored cyanobacteria crust and moss crust, the soil CO2 flux was decreased by 141% and 484%, respectively, as compared with that in bare land. The diurnal curve of soil CO2 flux under effects of biocrusts presented a trend of 'drop-rise-drop' , with the maximum carbon uptake under effects of cyanobacteria crust and moss crust being 0.13 and -1.02 micromol CO2.m-2.s-1 and occurred at about 8:00 and 9:00 am, respectively, while that in bare land was unimodal. In a day (24 h) , the total CO2 flux under effects of cyanobacteria crust was increased by 7.7% , while that under effects of moss crust was decreased by 29.6%, as compared with the total CO2 flux in bare land. This study suggested that in the hilly region of Loess Plateau, biocrust had significant effects on soil CO2 flux, which should be taken into consideration when assessing the carbon budget of the 'Grain for Green' eco-project. PMID:23755478

Wang, Ai-Guo; Zhao, Yun-Ge; Xu, Ming-Xiang; Yang, Li-Na; Ming, Jiao

2013-03-01

99

Impact of Global Change on Biological Processes in Soil  

Microsoft Academic Search

The Earth is undergoing rapid environmental changes due to human activities. Three components of the ongoing global change, elevated atmospheric CO2, N deposition, and global warming, may significantly impact soil biota directly through modifying the physical and chemical environment, and indirectly through altering aboveground plant growth and community composition. The biomass, community structure, and activities of microbes and animals in

Shuijin Hu; Weijian Zhang

2004-01-01

100

USE OF ACTIVATED CARBON FOR SOIL BIOREMEDIATION  

Microsoft Academic Search

The use of activated carbon may help overcome the toxicity of organic pollutants to microbes and plants during soil bioremediation.\\u000a Experiments were conducted with 3,4-dichloroaniline (DCA), 2,4,6-trinitrotoluene (TNT), and polychlorinated biphenyls (PCB)\\u000a to demonstrate that activated carbon (AC) can reduce the toxicity of readily available chemicals in soil by transferring them\\u000a to a less toxic soil fraction.

Galina K. Vasilyeva; Elena R. Strijakova; Patrick J. Shea

101

Concepts for Biologically Active Peptides  

PubMed Central

Here we review a unique aspect of CNS research on biologically active peptides that started against a background of prevalent dogmas but ended by exerting considerable influence on the field. During the course of refuting some doctrines, we introduced several concepts that were unconventional and paradigm-shifting at the time. We showed that (1) hypothalamic peptides can act ‘up’ on the brain as well as ‘down’ on the pituitary, (2) peripheral peptides can affect the brain, (3) peptides can cross the blood-brain barrier, (4) the actions of peptides can persist longer than their half-lives in blood, (5) perinatal administration of peptides can exert actions persisting into adulthood, (6) a single peptide can have more than one action, (7) dose-response relationships of peptides need not be linear, (8) the brain produces antiopiate as well as opiate peptides, (9) there is a selective high affinity endogenous peptide ligand for the mu-opiate receptor, (10) a peptide’s name does not restrict its effects, and (11) astrocytes assume an active role in response to metabolic disturbance and hyperleptinemia. The evolving questions in our laboratories reflect the diligent effort of the neuropeptide community to identify the roles of peptides in the CNS. The next decade is expected to see greater progress in the following areas: (a) interactions of peptides with other molecules in the CNS; (b) peptide involvement in cell-cell interactions; and (c) peptides in neuropsychiatric, autoimmune, and neurodegenerative diseases. The development of peptidomics and gene silencing approaches will expedite the formation of many new concepts in a new era.

Kastin, Abba J.; Pan, Weihong

2012-01-01

102

Biological and chemical degradation of tetraethyl lead in soil  

SciTech Connect

Tetraethyl lead (TEL) was first introduced by General Motors as an antiknock agent in gasoline in 1923. Its analogous chemical tetramethyl lead (TML) was introduced in 1960. The two chemicals were added to gasoline either singly or as mixtures to achieve desired octane numbers. Higher levels of lead in the urban environment have been attributed to extensive use of leaded gasoline in automobiles for over 50 yrs. With the advent of more sensitive analytical techniques in the late 1970 and early 1980, alkyl lead compounds were detected in aerosol dusts, rainwater, surface water, snow, sediments, soils, fish, and leaves. Ionic trialkyl lead (Triethyl lead (TREL) and trimethyl lead (TRML)) were the major species found. With the discontinuation of the use of leaded gasoline in automobiles the levels of alkyl lead in the environment should decline. Degradation pathways of tetraalkyl lead compounds in soil are not known. However, degradation pathways for tetraalkyl lead in aqueous solutions were proposed to proceed through a series of sequential dealkylation, and eventually to inorganic lead. Microorganisms capable of degrading tetraalkyl lead, including TEL, have not been reported. However, microbial degradation could be partially responsible for the disappearance of TRML in soil. Blais reported that the levels of TRML in nonsterile soil were lower than that in corresponding autoclaved soil after 24 hr of incubation. This study looks at biological and chemical transformation rates of TEL to ionic organolead forms (TREL and DEL), and mineralization rates of TEL in surface and subsurface soils. [sup 14]C-labeled TEL was used so that conversion from nonionic form to ionic form could easily be determined and evolution of CO[sub 2] from the mineralization of TEL could be measured. 17 refs., 3 figs., 2 tabs.

Ou, L.T.; Thomas, J.E.; Jing, T.W. (Univ. of Florida, Gainesville, FL (United States))

1994-02-01

103

Effects of Altered Temperature and Precipitation on Desert Protozoa Associated with Biological Soil Crusts  

Microsoft Academic Search

Biological soil crusts are diverse assemblages of bacteria, cyanobacteria, algae, fungi, lichens, and mosses that cover much of arid land soils. The objective of this study was to quantify protozoa associated with biological soil crusts and test the response of protozoa to increased temperature and precipitation as is predicted by some global climate models. Protozoa were more abundant when associated

BRIAN J. DARBY; DAVID C. HOUSMAN; AMR M. ZAKI; YASSEIN SHAMOUT; SINA M. ADL; JAYNE BELNAP; DEBORAH A. NEHER

2006-01-01

104

Physical and biological soil attributes due to soil management on sugarcane  

NASA Astrophysics Data System (ADS)

The use of different crops can improve the physical and biological soil attributes, reducing soil and environmental degradation. The objective of this study was to evaluate the effect of different land uses on the glomalin fractions, total external mycelium and soil aggregation. The experiment was carried out in Brazil (21°14'05'' S and 48°17'09'' W) in eutroferric Red Oxisol (clay content = 700 g kg-1) and acric Oxisol (clay content = 450 g kg-1). The soil was submitted to two soybean growing seasons, with different crops (millet and sunnhemp) between them, during two sugarcane growth interval periods. The experimental design was a randomized block with five replications and four treatments, characterized by different land uses during the interval between two sugarcane growth periods. The land uses were the crops of: soybean, soybean/millet/soybean, soybean/sunnhemp/soybean and soybean/fallow/soybean. Soil samples were taken at the 0 - 0.10 m depth after the first sugarcane harvest. On both soils the glomalin fractions were not influenced by the different land uses. On the eutroferric Red Oxisol, the use soybean/millet/soybean promoted the higher amount of total external mycelium and on the acric Oxisol soybean/fallow/soybean promoted the lower amount. The aggregate stability indexes on both soils types were not affected by the land uses. On the eutroferric Red Oxisol, the aggregate mean weight diameter was not influenced by the different land uses, but on the acric Oxisol, the uses soybean and soybean/millet/soybean promoted the higher values. The results indicated that the effects of plants on amount of total external mycelium and aggregate mean weight diameter of Oxisol are different depend upon the soil texture and soil fertility.

Fernandes, Carolina; Viviane Truber, Priscila; Corá, José Eduardo

2013-04-01

105

Stabilization of labile organic C along a chronosequence of soil development: mineralogical vs. biological controls  

NASA Astrophysics Data System (ADS)

Soil organic matter (SOM) represents an important reservoir for carbon (C), nitrogen (N), and other essential nutrients. Consequently, variation in SOM turnover rates regulates resource availability for soil microbial activity and plant growth. Long-term SOM stabilization generally involves restricted microbial access to SOM through a variety of processes including complexation with soil minerals. These organo-mineral interactions are influenced by mineral composition and texture, often related to soil age. Soil microorganisms also influence the stabilization of C inputs to the pedosphere through the production of refractory residues controlled in part by C allocation patterns during metabolism. In this study we examined, simultaneously, the contribution of these two C stabilizing mechanisms by ‘tracing’ the fate of two 13C-labeled substrates (glucose and p-hydroxybenzoic acid) along a 1600Kya chronosequence of soil development along the Cowlitz River in southwest Washington. Our objective was to evaluate the relationship between mineralogical and biological controls over C sequestration in soils. Mineralogical analyses were done using the selective dissolutions ammonium oxalate (AOD), and dithionite-citrate extraction (CBD). In this cool, humid environment, intermediate aged soils derived from the late Wisconsin Evans Creek drift (24ka) had the highest AOD extractable Al, Fe, and Si, indicating a higher concentration of poorly crystalline minerals relative to other terraces. Correspondingly, CBD extractable Fe increases with soil age, further supporting the idea that crystalline iron oxides are also more prevalent with weathering. Turnover of both 13C-labeled substrates was rapid (< 12.5 hrs) However, the proportion of substrate mineralized to CO2 varied among terraces. Mineralization to CO2 was significantly lower at 24ka than that for the other three age classes (0.25k, 220k, and 1,600k years bp), corresponding to higher recovery of 13C in bulk soil for this age class. In similar studies, soils containing a higher proportion of poorly crystalline minerals typically have a higher degree of hydration, surface area, and variable charge, which can increase microbial yield, reducing the amount of CO2 produced per unit biomass and increasing potential for soil C sequestration. Additionally, total flux of 13CO2 was significantly higher and recovery of 13C in microbial pools trended lower for the phenolic than for glucose for all soils types excluding the 24ka terrace. The broader implication, which may warrant consideration in models of terrestrial C flux, is that altering the constituency of labile C inputs to these soil environments could similarly influence the degree to which C is stabilized in soil mineral assemblages.

McFarland, J. W.; Waldrop, M. P.; Strawn, D.; Harden, J. W.

2010-12-01

106

Genomics Activities - Center for Biologics Evaluation and ...  

Center for Biologics Evaluation and Research (CBER)

Text VersionPage 1. Genomics Activities Center for Biologics Evaluation and Research ... Page 7. New Activities at CBER Supporting Genomics Research ... More results from www.fda.gov/downloads/advisorycommittees/committeesmeetingmaterials

107

Biological Soil Disinfestation (BSD) of Soilborne Pathogens and Its Possible Mechanisms  

Microsoft Academic Search

Biological soil disinfestation (BSD) is one of the methods for soil disinfestation recently developed and consists of organic amendment, irrigation, and covering the soil surface with plastic film. BSD trials with artificially infested soils effectively killed Fusarium oxysporum f. sp. lycopersici and Ralstonia solanacearum. F. oxysporum f. sp. lycopersici was not detected 9 days after treatment. Application of BSD to

Noriaki MOMMA

2008-01-01

108

Soil tillage induced impacts on soil microbial activity of agriculturally used soils in Austria  

NASA Astrophysics Data System (ADS)

Soil can act as a net sink for sequestering carbon and thus attenuating the increase in atmospheric CO2 if appropriate soil and crop management is applied. The objectives of this study are to determine the impacts of different tillage treatments on soil microbial activity. Soil microbial respiration (MR), substrate-induced respiration (SIR), ß-glucosidase activity (GLU) and dehydrogenase (DHY) activity were analysed for five agricultural fields in Lower Austria and Styria in 2007 and 2008. These investigations are part of a research project about the influence of soil tillage on CO2 emissions and carbon dynamics of Austrian cropland. The study sites differ in climatic conditions, soil texture, slope and crop rotation. All fields belong to long-term tillage treatment experiments performed by agricultural schools. Three different tillage systems are investigated: Conventional tillage (CT), Reduced tillage (RT) and No-tillage (NT). RT and NT use cover crops during the winter period. Each tillage system is replicated three times per site. In spring, summer and autumn 2007 and 2008, soil samples were taken from each plot at the soil depth of 0-10 cm, 10-20 cm and 20-30 cm. Samples were sieved (2 mm) and stored at 4°C in a refrigerator. Analyses were performed within one month after sampling. In addition, soil moisture, pH value and carbon and nitrogen content of the soil samples were determined. Preliminary results show that the amount of microbiological activity differs between the five sites during experimental years depicting the influence of soil texture. The influence of tillage treatment on soil microbial parameter was best represented by SIR. For all fields, values changed during the vegetation period. The impact of soil texture and soil depth could be analysed by all investigated soil microbial parameters whereas the tillage treatment showed a significant influence only for SIR.

Baatar, Undrakh-Od; Klik, Andreas; Trümper, Gerlinde

2010-05-01

109

Influence of shrub species and biological soil crust cover on nutrient distribution in a semiarid sand dune area (Negev, Israel)  

NASA Astrophysics Data System (ADS)

Deserts are expanding and the restoration of barren lands is of great importance. To achieve this goal the understanding of soil-plant interactions is necessary. In semiarid systems the biogeochemical cycles are strongly linked to "fertile islands" which are surrounded by bare interspaces, areas mostly covered by biological soil crusts. These microbiological communities have great influence runoff, nutrient fixation and soil stability. This spatial horizontal pattern on the surface leads to vertical distribution patterns of nutrients. For a re-established sand dune system in the Negev (Israel) this pattern is highly depending on surface cover. Here unconsolidated sand dunes have been stabilised by the growth of biological soil crust leading to an establishment of perennial shrubs. After 15 years of landuse exclusion a clear spatial pattern in the amount of different soil cations and anions can be proofed. Our results show significant difference for potassium, manganese, calcium, sodium and chloride under biological soil crusts, the chenopod Anabasis articulata and the legume Retama raetam. This redistribution on behalf of biological processes can be shown for 3 study sites along a sharp precipitation gradient (90 mm per year up to 170 mm per year). The comparison of the study sites shows changes in the distribution patterns with increasing precipitation not only due to higher leaching or differences in dust input but changes in plant activity. The plant essential potassium proofs to be the best indicator for redistribution processes. The not plant essential sodium is non-normally distributed as Anabasis articulata and the biological soil crust accumulate this cation. Perennial shrubs and biological soil crusts are important ecosystem engineers. They have the ability to enrich ecosystems with cations and anions. The mechanisms of redistribution depend on soil cover and amount of precipitation and are, contradictory to earlier results, not independent from shrub species.

Drahorad, S.; Felix-Henningsen, P.

2009-04-01

110

Nitrogen Fixation and Leaching of Biological Soil Crust Communities in Mesic Temperate Soils  

Microsoft Academic Search

Biological soil crust is composed of lichens, cyanobacteria, green algae, mosses, and fungi. Although crusts are a dominant\\u000a source of nitrogen (N) in arid ecosystems, this study is among the first to demonstrate their contribution to N availability\\u000a in xeric temperate habitats. The study site is located in Lucas County of Northwest Ohio. Using an acetylene reduction technique,\\u000a we demonstrated

Roberta M. Veluci; Deborah A. Neher; Thomas R. Weicht

2006-01-01

111

ENZYME ACTIVITIES IN SEMIARID AGRICULTURAL SOILS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Knowledge of biochemical processes in low carbon content soils of the semiarid regions in West Texas, USA, in response to different land management is limited. The activities of seven soil enzymes involved in C, N, P, or S cycling were compared in an Olton loam (Fine, mixed, thermic, superactive, A...

112

Dehydrogenase activity in Mediterranean forest soils  

Microsoft Academic Search

The dehydrogenase activity (DHA) in the upper 10 cm of forest soils was measured in three experimental plots (1 ha) in Los Alcornocales Natural Park (southern Spain). In each plot, a sylviculture treatment of thinning and shrub-clearing had been previously carried out in one half, while the other half was left as a forest control. Soil samples were taken during

Consuelo Quilchano; Teodoro Marañón

2002-01-01

113

Microbial Activity of Soil Following Steam Treatment  

Microsoft Academic Search

The effect of steam treatment on subsurface aerobic and anaerobic microbial communities was investigated using multiple microbial assays. Soil samples were gathered and analyzed prior to, one month after, and eight months after a five-month field pilot test of steam injection and extraction. Aerobic soil samples were analyzed by respirometry, plate counts, and direct microscopic counts. Anaerobic microbial activity was

Barbara Orchard; Yarrow M. Nelson; Lynne Maloney; Christopher L. Kitts; Paul Lundegard

2005-01-01

114

Rain pulse response of soil CO2 exchange by biological soil crusts and grasslands of the semiarid Colorado Plateau, United States  

USGS Publications Warehouse

Biological activity in arid grasslands is strongly dependent on moisture. We examined gas exchange of biological soil crusts (biocrusts), the underlying soil biotic community, and the belowground respiratory activity of C3 and C4 grasses over 2 years in southeast Utah, USA. We used soil surface CO2 flux and the amount and carbon isotope composition (?13C) of soil CO2 as indicators of belowground and soil surface activity. Soil respiration was always below 2 ?mol m-2s-1 and highly responsive to soil moisture. When moisture was available, warm spring and summer temperature was associated with higher fluxes. Moisture pulses led to enhanced soil respiration lasting for a week or more. Biological response to rain was not simply dependent on the amount of rain, but also depended on antecedent conditions (prior moisture pulses). The short-term temperature sensitivity of respiration was very dynamic, showing enhancement within 1-2 days of rain, and diminishing each day afterward. Carbon uptake occurred by cyanobacterially dominated biocrusts following moisture pulses in fall and winter, with a maximal net carbon uptake of 0.5 ?mol m-2s-1, although typically the biocrusts were a net carbon source. No difference was detected in the seasonal activity of C3 and C4 grasses, contrasting with studies from other arid regions (where warm- versus cool-season activity is important), and highlighting the unique biophysical environment of this cold desert. Contrary to other studies, the ?13C of belowground respiration in the rooting zone of each photosynthetic type did not reflect the ?13C of C3 and C4 physiology.

Bowling, D. R.; Grote, E. E.; Belnap, J.

2011-01-01

115

The effect of model soil contamination with Cr, Cu, Ni, and Pb on the biological properties of soils in the dry steppe and semidesert regions of southern Russia  

NASA Astrophysics Data System (ADS)

Model soil contamination with Cr, Cu, Ni, and Pb in the dry steppes and semideserts of southern Russia has worsened the biological soil properties. With respect to the degree of deterioration of the biological properties, the soils can be arranged in the following sequence: dark chestnut soils > chestnut soils > light chestnut soils > brown semidesert soils > sandy brown semidesert soils. The sequence of metal oxides according to the adverse effect on the biological soil properties is as follows: CrO3 > CuO ? PbO ? NiO.

Kolesnikov, S. I.; Spivakova, N. A.; Kazeev, K. Sh.

2011-09-01

116

Microbiological activity of soils populated by Lasius niger ants  

NASA Astrophysics Data System (ADS)

Ants are the most widespread colonial insects assigned to the Hymenoptera order. They actively use soil as a habitat; being numerous, they create a specific microrelief. It is shown that ants affect microbiological processes of the carbon and nitrogen cycles. The carbon content in anthills remains stable throughout the growing season, and the respiration intensity is about three times higher as compared with that in the control soil. The highest methane production (0.08 nmol of CH4/g per day) in the anthill is observed at the beginning of the growing season and exceeds that in the control soil by four times. The most active nitrogen fixation (about 4 nmol of C2H4/g per h) in the anthill takes place in the early growing season, whereas, in the control soil, it is observed in the middle of the growing season. At the same time, the diazotrophic activity is higher in the control soil. The lowest denitrification in the anthill is observed at the beginning and end of the growing season. The dynamics of the denitrification in the anthill are opposite to the dynamics of the diazotrophic activity. We suppose that these regularities of the biological activity in the anthill are related to the ecology of the ants and the changes in their food preferences during the growing season.

Golichenkov, M. V.; Neimatov, A. L.; Kiryushin, A. V.

2009-07-01

117

Biological reduction of uranium in groundwater and subsurface soil.  

PubMed

Biological reduction of uranium is one of the techniques currently studied for in situ remediation of groundwater and subsurface soil. We investigated U(VI) reduction in groundwaters and soils of different origin to verify the presence of bacteria capable of U(VI) reduction. The groundwaters originated from mill tailings sites with U concentrations as high as 50 mg/l, and from other sites where uranium is not a contaminant, but was added in the laboratory to reach concentrations up to 11 mg/l. All waters contained nitrate and sulfate. After oxygen and nitrate reduction, U(VI) was reduced by sulfate-reducing bacteria, whose growth was stimulated by ethanol and trimetaphosphate. Uranium precipitated as hydrated uraninite (UO2 x xH2O). In the course of reduction of U(VI), Mn(IV) and Fe(III) from the soil were reduced as well. During uraninite precipitation a comparatively large mass of iron sulfides formed and served as a redox buffer. If the excess of iron sulfide is large enough, uraninite will not be oxidized by oxygenated groundwater. We show that bacteria capable of reducing U(VI) to U(IV) are ubiquitous in nature. The uranium reducers are primarily sulfate reducers and are stimulated by adding nutrients to the groundwater. PMID:10811248

Abdelouas, A; Lutze, W; Gong, W; Nuttall, E H; Strietelmeier, B A; Travis, B J

2000-04-24

118

Six Siderophore-Producing Microorganisms Identified in Biological Soil Crusts  

NASA Astrophysics Data System (ADS)

Biological soil crusts (BSCs) are diverse microbial communities that colonize soils in arid and semi-arid environments. Cyanobacteria in BSCs are pioneer organisms that increase ecosystem habitability by providing fixed carbon (C) and nitrogen (N) as well as by reducing water run-off and increasing infiltration. Photosynthesis and N fixation, in particular, require a variety of metals in large quantities, and yet, metals are predominantly insoluble in the environments where BSCs thrive. Therefore, BSC organisms must have efficient strategies for extracting metals from soil minerals. We hypothesized that BSC microbes, particularly the cyanobacteria, produce siderophores to serve their metal-acquisition needs. Siderophores are small organic compounds that bind Fe with high affinity and are produced by a variety of microorganisms, including cyanobacteria. Most siderophores bind Fe, primarily; however, some can also bind Mo, V, and Cu. Soil siderophores are released by microbes to increase the solubility of metals from minerals and to facilitate microbial uptake. Thus, siderophores serve as chemical weathering agents and provide a direct link between soil microbes and minerals. Studying siderophore production in BSCs provides insight into how BSCs tackle the challenge of acquiring insoluble metals, and may help conservationists determine useful fertilizers for BSC growth by facilitating metal acquisition. Biological soil crusts were collected near Moab, UT. Soil slurries were prepared in deionized water and transferred to modified BG-11 agar plates. The O-CAS agar plate assay was used to screen organisms for siderophore production. Siderophore producing microbes were isolated and identified by16S rRNA gene sequencing. Cultures were then grown in 3 L batch cultures under metal limitation, and siderophore presence was monitored using the traditional liquid CAS assay. After siderophore detection, cells were removed by centrifugation, organic compounds were separated using Amberlite° XAD° 2 resin and a C-18 column, and siderophores were detected with electrospray-ionization mass spectrometry (ESI-MS). Column eluants were analyzed with and without Fe addition. Siderophores were identified as those peaks that decreased upon Fe addition (unbound) with a corresponding increase in the mass plus Fe peak (Fe-bound). Of the organisms isolated, 42 out of 182 produce siderophores (23%). At this time 6 unique siderophore-producing organisms have been identified in the genera Balneimonas, Microvirga, Bacillus, and the Group IV cyanobacteria. Siderophore production in BSCs is performed by both heterotrophs and phototrophs, and we present phylogenetic data for these isolates. A comparison with organisms previously identified in BSC communities indicates that the siderophore-producers represent some of the dominant crust microbes (i.e., Nostoc sp.). This is the first report of siderophore production in BSCs, and thus it is a significant step towards understanding biologically-mediated metal cycling in arid ecosystems.

Noonan, K.; Anbar, A. D.; Garcia-Pichel, F.; Poret-peterson, A. T.; Hartnett, H. E.

2011-12-01

119

Microbial activity in soils following steam treatment.  

PubMed

Steam enhanced extraction (SEE) is an aquifer remediation technique that can be effective at removing the bulk of non-aqueous phase liquid (NAPL) contamination from the subsurface, particularly highly volatile contaminants. However, low volatility compounds such as polynuclear aromatic hydrocarbons (PAHs) are less efficiently removed by this process. This research evaluated the effects of steam injection on soil microbial activity, community structure, and the potential for biodegradation of contaminants following steam treatment. Three different soils were evaluated: a laboratory-prepared microbially-enriched soil, soil from a creosote contaminated field site, and soil from a chlorinated solvent and waste oil contaminated field site. Results from field-scale steaming are also presented. Microbial activity before and after steam treatment was evaluated using direct epifluorescent microscopy (DEM) using the respiratory activity dye 5-cyano-2,3, ditolyl tetrazolium chloride (CTC) in conjunction with the fluorochrome 5-(4,6-dichlorotriazinyl) aminofluorescein (DTAF) to yield a quantitative assessment of active and total microbial numbers. DEM results indicate that steamed soils that were analyzed while still hot exhibited microbial activity levels that were below detection. However, soil samples that were slowly cooled, more closely reflecting the conditions of applied SEE, exhibited microbial activity levels that were comparable to presteamed soils. Samples from a field-site where steam was applied continuously for 6 weeks also showed high levels of microbial activity following cooling. The metabolic capabilities of the steamed communities were investigated by measuring cell growth in enrichment cultures on various substrates. These studies provided evidence that organisms capable of biodegradation were among the mesophilic populations that survived steam treatment. Fluorescent in situ hybridization (FISH) analysis of the soils with domain-level rRNA probes suggest that both Archaea and Bacteria survived steam exposure. PMID:12521292

Richardson, Ruth E; James, C Andrew; Bhupathiraju, Vishvesh K; Alvarez-Cohen, Lisa

2002-01-01

120

Minds-On Activities for Teaching Biology  

NSDL National Science Digital Library

These minds-on activities include discussion activities, web-based activities, experiments and simulation activities to foster student understanding of important concepts in the life sciences. Topics covered include biological molecules, membranes and osmosis, cellular respiration and photosynthesis, cell structure and function, cell division, genetics, molecular biology, evolution, diversity, human physiology and health, and design and interpretation of experiments. These activities were designed for teaching high school students, but many of them can also be used with middle school students or in non-major introductory college biology classes. Most of the activities are described in student handouts and teacher notes; the student handouts are available as Word files for teachers to customize for their students. The hands-on experiments and simulation activities are available at http://serendip.brynmawr.edu/sci_edu/waldron/. To accommodate limited budgets, most of the hands-on activities can be carried out with minimum equipment and expense for supplies.

Waldron, Ingrid; Doherty, Jennifer

121

Heavy metal pollution and soil enzymatic activity  

Microsoft Academic Search

The activity of hydrolytic soil enzymes was studied on spruce mor, polluted with Cu and Zn from a brass foundry in Sweden. Approximately straight regression lines were obtained between enzymatic activity or respiration rate and log Cu+Zn concentration, with highly significant negative regression coefficients for urease and acid phosphatase activity as well as respiration rate, whereas ß-glucosidase activity was not

Germund Tyler

1974-01-01

122

Spectroscopic study of biologically active glasses  

Microsoft Academic Search

It is known that the chemical activity phenomenon is characteristic for some inorganic glasses and they are able to participate in biological processes of living organisms (plants, animals and human bodies). An example here is the selective removal of silicate–phosphate glass components under the influence of biological solutions, which has been applied in designing glasses acting as ecological fertilizers of

M. Szumera; I. Wac?awska; W. Mozgawa; M. Sitarz

2005-01-01

123

Impacts of off-road vehicles on nitrogen cycles in biological soil crusts: Resistance in different U.S. deserts  

USGS Publications Warehouse

Biological soil crusts are an important component of desert ecosystems, as they influence soil stability and fertility. This study examined and compared the short-term vehicular impacts on lichen cover and nitrogenase activity (NA) of biological soil crusts. Experimental disturbance was applied to different types of soil in regions throughout the western U.S. (Great Basin, Colorado Plateau, Sonoran, Chihuahuan, and Mojave deserts). Results show that pre-disturbance cover of soil lichens is significantly correlated with the silt content of soils, and negatively correlated with sand and clay. While disturbance appeared to reduce NA at all sites, differences were statistically significant at only 12 of the 26 sites. Cool desert sites showed a greater decline than hot desert sites, which may indicate non-heterocystic cyanobacterial species are more susceptible to disturbance than non-heterocystic species. Sandy soils showed greater reduction of NA as sand content increased, while fine-textured soils showed a greater decline as sand content increased. At all sites, higher NA before the disturbance resulted in less impact to NA post-disturbance. These results may be useful in predicting the impacts of off-road vehicles in different regions and different soils. ?? 2002 Published by Elsevier Science Ltd.

Belnap, J.

2002-01-01

124

Comparative biological activities of two nucleopolyhedrovirus ...  

Treesearch

... active against insects reared on artificial diet than those reared on foliage. ... viral preparations, nucleopolyhedrovirus, biological pest control, Virin NSH, Gypchek ... This article was written and prepared by U.S. Government employees on ...

125

Influence of development stage and disturbance of physical and biological soil crusts on soil water erosion  

NASA Astrophysics Data System (ADS)

Most soils exposed to rainfall are prone to sealing and crusting processes causing physical soil crusts (PSCs). When climate and soil stability conditions are suitable, PSCs can be consolidated by a complex community consisting of cyanobacteria, bacteria, green algae, microfungi, lichens and bryophytes, which are collectively known as biological soil crust (BSC). The influence of soil crusts on erosion processes is complex: crusts may reduce detachment, increasing soil stability and protecting soil against raindrop impact, although that protection will depend on the type of soil crust and the stage of development; they can also build up runoff, suggesting that downstream erosion may actually be increased or favoured water harvesting to vegetated areas. On the other hand, BSCs have been demonstrated to be very vulnerable to disturbance which in turn can lead to accelerate soil erosion and other forms of land degradation. Incorporation of the response of different type of soil crusts and the effects of their disturbance is highly likely to improve the prediction of runoff and water erosion models in arid and semi-arid catchments. The objective of this work is to analyse the erosional response of PSCs and BSCs in different stages of their development and subject to distinct disturbances when extreme rainfalls intensities are applied at plot scale in semiarid environments. Small plots on the most representative crust types, corresponding to different stages of crust development, in two semiarid ecosystems in SE Spain, El Cautivo (in the Tabernas Desert) and Amoladeras (in the Natural Park Cabo de Gata-Níjar), were selected and three disturbance treatments were applied on each crust type: a) no disturbance (control), b) trampling, stepping 100 times over the crust and c) scraping. Two consecutive rainfall simulation experiments (50 mm/h rainfall intensity) were carried out on each plot: the first on dry soil and the second, 30 minutes later, on wet soil conditions. Samples of runoff were collected regularly during the rainfall simulation and sediments in runoff extracted later in laboratory. Erosion rates were significantly different at both sites, being lower in Amoladeras than in El Cautivo due to a flatter topography and a higher infiltration capacity of the sandy soils with higher organic matter content. There were not significant differences on total erosion rates between the first and the second rainfall event, as consequence of the increase of runoff under wet conditions. In El Cautivo, the erosion rates significantly decreased as crust development stage increased. However, in Amoladeras, the erosion was low in all crust types and there were not significant differences on erosion rates among the crust development stages. Among treatments, in El Cautivo, scraping and trampling promoted significant higher erosion rates than undisturbed crust, but no significant differences were found between both treatments, except for the lichen-dominated crust. In Amoladeras, no significant differences on erosion rates between the undisturbed and the trampled crust were found since in this area trampling did not have an important effect. Although the removal of the crust in semiarid environments, at local scale, always increased erosion, the effects of crust disturbance on erosion varied depending on the ecosystem, with stronger erosional effects in badland areas with a silty substrate and steep topography than in areas with a flat topography and a coarser soil texture.

Chamizo, S.; Cantón, Y.; Lázaro, R.; Solé-Benet, A.; Calvo-Cases, A.; Miralles, I.; Domingo, F.

2009-04-01

126

Mercury speciation and effects on soil microbial activities  

Microsoft Academic Search

To study Hg toxicity on soil microbes and their activities, it is necessary to understand its various forms in soils. The objectives of this study were to investigate Hg speciation in four soil types spiked with Hg (300 mg kg soil) and its effects on soil microbial respiration and enzymes (amidohydrolases and phosphatase) activities. An assessment of the chemical forms,

Irenus A. Tazisong; Zachary N. Senwo; Miranda I. Williams

2012-01-01

127

Biologics Post-Market Activities  

Center for Biologics Evaluation and Research (CBER)

... These post-market activities include lot release (for some products), post-marketing adverse event reporting, and post-marketing study ... More results from www.fda.gov/biologicsbloodvaccines/guidancecomplianceregulatoryinformation/post-marketactivities

128

Persistence of biologically active compounds in aquatic systems: Final report  

SciTech Connect

Waters collected from two study sites were tested for persistence of biologically active compounds as the waters percolated through experimental media. At the first site, the Paraho Lysimeter in Anvil Points, Colorado, two leachate samples (early and late flow in Spring 1983) were collected from each of four piles of processed oil shale overlain by different thicknesses of soil. Although water quality differed among samples, six of eight lysimeter leachates tested were acutely toxic to an aquatic invertebrate, Daphnia magna, and five were acutely toxic to fathead minnows (Pimephales promelas). Water collected from a modified in situ (MIS) retort was percolated through columns containing three different types of soil. Raw leachate from the MIS spent shale was acutely toxic to an aquatic invertebrate, Ceriodaphnia dubia. The toxicity of samples from nine pore volumes of retort water percolating through a column containing a sandy soil increased with successive pore volumes, but leachate toxicity never equaled the toxicity of the retort water. In contrast, the first pore volumes of retort water or reconstituted water leached through a sandy loam soil were more toxic than the retort water; however, the second pore volumes of leachates were not toxic. First pore volume leachates of retort water percolating through a sandy clay loam soil were much less toxic than the retort water; second pore volume leachates were not toxic.

Boelter, A.M.; Fernandez, J.D.; Meyer, J.S.; Sanchez, D.A.; Bergman, H.L.

1986-11-01

129

“In situ” vermicomposting of biological sludges and impacts on soil quality  

Microsoft Academic Search

A laboratory experiment was carried out to study soil quality amelioration through “in situ” vermicomposting of biological sludges. The experiment dealt with the stabilization, through the action of worms (Eisenia fetida), of five mixtures containing aerobic and anaerobic biological sludges spread on the soil surface. The results showed that by increasing the percentage of anaerobic sludge in the mixtures, the

G Masciandaro; B Ceccanti; C Garcia

2000-01-01

130

The influence of biological soil crusts on mineral uptake by associated vascular plants  

Microsoft Academic Search

Soil surfaces dominated by cyanobacteria and cyanolichens (such as Collema sp.) are widespread in deserts of the world. The influence of these biological soil crusts on the uptake of bioessential elements is reported for the first time for six seed plants of the deserts of Utah. This sample almost doubles the number of species for which the influence of biological

Kimball T. Harper; Jayne BelnapK

2001-01-01

131

Remote sensing of biological soil crust under simulated climate change manipulations in the Mojave Desert  

Microsoft Academic Search

Earth's arid and semiarid ecosystems are subject to novel combinations of disruptive factors and unprecedented rates of change. Biotic soil crust is believed to be sensitive to impacts caused by land use and climate changes. This study examined the potential for spectral detection of different biological soil crusts (BSC: cyanobacteria, moss and lichen) and bare soil components at a long-term

Susan L. Ustin; Phillip G. Valko; Shawn C. Kefauver; Maria J. Santos; Jeff F. Zimpfer; Stanley D. Smith

2009-01-01

132

Effects of acute gamma irradiation on chemical, physical and biological properties of soils  

Microsoft Academic Search

The use of gamma (?-) irradiation as a method for soil sterilisation for laboratory experiments has been recommended over other sterilisation techniques. We reviewed literature dating back over 50 years to investigate the chemical and biological effects on ?-irradiated soils and to determine its practicality for sterilising soils which will subsequently be used for experimental purposes. Typically, ?-irradiation at 10kGy

N. P. McNamara; H. I. J. Black; N. A. Beresford; N. R. Parekh

2003-01-01

133

The potential roles of biological soil crusts in dryland hydrologic cycles  

NASA Astrophysics Data System (ADS)

Biological soil crusts (BSCs) are the dominant living cover in many drylands of the world. They possess many features that can influence different aspects of local hydrologic cycles, including soil porosity, absorptivity, roughness, aggregate stability, texture, pore formation, and water retention. The influence of biological soil crusts on these factors depends on their internal and external structure, which varies with climate, soil, and disturbance history. This paper presents the different types of biological soil crusts, discusses how crust type likely influences various aspects of the hydrologic cycle, and reviews what is known and not known about the influence of biological crusts on sediment production and water infiltration versus runoff in various drylands around the world. Most studies examining the effect of biological soil crusts on local hydrology are done by comparing undisturbed sites with those recently disturbed by the researchers. Unfortunately, this greatly complicates interpretation of the results. Applied disturbances alter many soil features such as soil texture, roughness, aggregate stability, physical crusting, porosity, and bulk density in ways that would not necessarily be the same if crusts were not naturally present. Combined, these studies show little agreement on how biological crusts affect water infiltration or runoff. However, when studies are separated by biological crust type and utilize naturally occurring differences among these types, results indicate that biological crusts in hyperarid regions reduce infiltration and increase runoff, have mixed effects in arid regions, and increase infiltration and reduce runoff in semiarid cool and cold drylands. However, more studies are needed before broad generalizations can be made on how biological crusts affect infiltration and runoff. We especially need studies that control for sub-surface soil features such as bulk density, micro- and macropores, and biological crust structure. Unlike the mixed effects of biological crusts on infiltration and runoff among regions, almost all studies show that biological crusts reduce sediment production, regardless of crust or dryland type.

Belnap, Jayne

2006-10-01

134

Functions of biological soil crusts on central European inland dunes: Water repellency and pore clogging influence water infiltration  

Microsoft Academic Search

Biological soil crusts play a key role for hydrological processes in many open landscapes. They seal and stabilize the topsoil and promote surface run-off. Three crust types were identified on two inland dunes in Brandenburg, North-East Germany: A natural, active dune, located in a former military training area near Lieberose, and an artificial dune, which was constructed in 2001 and

Thomas Fischer; Roland Spröte; Maik Veste; Wolfgang Wiehe; Philipp Lange; Oliver Bens; Thomas Raab; Reinhard F. Hüttl

2010-01-01

135

Biological soil crust succession impact on soil moisture and temperature in the sub-surface along a rainfall gradient  

NASA Astrophysics Data System (ADS)

Biological soil crusts produce mucilage sheets of polysaccharides that cover the soil surface. This hydrophobic coating can seal the soil micro-pores and thus cause reduction of water permeability and may influence soil temperature. This study evaluates the impact of crust composition on sub-surface water and temperature over time. We hypothesized that the successional stages of biological soil crusts, affect soil moisture and temperature differently along a rainfall gradient throughout the year. Four experimental sites were established along a rainfall gradient in the western Negev Desert. At each site three treatments; crust removal, pure sand (moving dune) and natural crusted were monitored. Crust successional stage was measured by biophysiological and physical measurements, soil water permeability by field mini-Infiltrometer, soil moisture by neutron scattering probe and temperature by sensors, at different depths. Our main interim conclusions from the ongoing study along the rainfall gradient are: 1. the biogenic crust controls water infiltration into the soil in sand dunes, 2. infiltration was dependent on the composition of the biogenic crust. It was low for higher successional stage crusts composed of lichens and mosses and high with cyanobacterial crust. Thus, infiltration rate controlled by the crust is inverse to the rainfall gradient. Continuous disturbances to the crust increase infiltration rates, 3. despite the different rainfall amounts at the sites, soil moisture content below 50 cm is almost the same. We therefore predict that climate change in areas that are becoming dryer (desertification) will have a positive effect on soil water content and vice versa.

Zaady, E.; Yizhaq, H.; Ashkenazy, Y.

2012-04-01

136

Phenol oxidase activity in secondary transformed peat-moorsh soils  

NASA Astrophysics Data System (ADS)

The chemical composition of peat depends on the geobotanical conditions of its formation and on the depth of sampling. The evolution of hydrogenic peat soils is closely related to the genesis of peat and to the changes in water conditions. Due to a number of factors including oscillation of ground water level, different redox potential, changes of aerobic conditions, different plant communities, and root exudes, and products of the degradation of plant remains, peat-moorsh soils may undergo a process of secondary transformation conditions (Sokolowska et al. 2005; Szajdak et al. 2007). Phenol oxidase is one of the few enzymes able to degrade recalcitrant phenolic materials as lignin (Freeman et al. 2004). Phenol oxidase enzymes catalyze polyphenol oxidation in the presence of oxygen (O2) by removing phenolic hydrogen or hydrogenes to from radicals or quinines. These products undergo nucleophilic addition reactions in the presence or absence of free - NH2 group with the eventual production of humic acid-like polymers. The presence of phenol oxidase in soil environments is important in the formation of humic substances a desirable process because the carbon is stored in a stable form (Matocha et al. 2004). The investigations were carried out on the transect of peatland 4.5 km long, located in the Agroecological Landscape Park host D. Chlapowski in Turew (40 km South-West of Pozna?, West Polish Lowland). The sites of investigation were located along Wysko? ditch. The following material was taken from four chosen sites marked as Zbechy, Bridge, Shelterbelt and Hirudo in two layers: cartel (0-50cm) and cattle (50-100cm). The object of this study was to characterize the biochemical properties by the determination of the phenol oxidize activity in two layers of the four different peat-moors soils used as meadow. The phenol oxidase activity was determined spectrophotometrically by measuring quinone formation at ?max=525 nm with catechol as substrate by method of Perucci et al. (2000). In peat the highest activities of phenol oxidase was observed in the combinations marked as Shelterbelt and whereas the lowest - in Zbechy, Bridge and Hirudo. Activities of this enzyme in peat ranged from 15.35 to 38.33 ?mol h-1g d.m soil. Increased activities of phenol oxidase have been recorded on the depth 50-100cm - catotelm (21.74-38.33 ?mol h-1g d.m soil) in comparison with the depth 0-50cm - acrotelm (15.35-28.32 ?mol h-1g d.m soil). References Freeman, C., Ostle N.J., Fener, N., Kang H. 2004. A regulatory role for phenol oxidase during decomposition in peatlands. Soil Biology and Biochemistry, 36, 1663-1667. Matocha Ch.J., Haszler G.R., Grove J.H. 2004. Nitrogen fertilization suppresses soil phenol oxidase enzyme activity in no-tillage systems. Soil Science, 169/10, 708-714. Perucci P., Casucci C., Dumontet S. 2000. An improved method to evaluate the o-diphenol oxidase activity of soil. Soil Biology and Biochemistry, 32, 1927-1933. Sokolowska Z., Szajdak L., Matyka-Sarzy?ska D. 2005. Impact of the degree of secondary transformation on amid-base properties of organic compounds in mucks. Geoderma, 127, 80-90. Szajdak L., Szczepa?ski M., Bogacz A. 2007. Impact of secondary transformation of peat-moorsh soils on the decrease of nitrogen and carbon compounds in ground water. Agronomy Research, 5/2, 189-200.

Sty?a, K.; Szajdak, L.

2009-04-01

137

Loranthus micranthus Linn.: Biological Activities and Phytochemistry  

PubMed Central

Loranthus micranthus Linn. is a medicinal plant from the Loranthaceae family commonly known as an eastern Nigeria species of the African mistletoe and is widely used in folkloric medicine to cure various ailments and diseases. It is semiparasitic plant because of growing on various host trees and shrubs and absorbing mineral nutrition and water from respective host. Hence, the phytochemicals and biological activities of L. micranthus demonstrated strong host and harvesting period dependency. The leaves have been proved to possess immunomodulatory, antidiabetic, antimicrobial, antihypertensive, antioxidant, antidiarrhoeal, and hypolipidemic activities. This review summarizes the information and findings concerning the current knowledge on the biological activities, pharmacological properties, toxicity, and chemical constituents of Loranthus micranthus.

Zorofchian Moghadamtousi, Soheil; Hajrezaei, Maryam; Abdul Kadir, Habsah

2013-01-01

138

Biological activity of vanadium compounds  

Microsoft Academic Search

Vanadium compounds are characterised by a broad spectrum of action in vivo and in vitro. Their insulin-mimetic activity is manifested in their ability to normalize changes observed in both clinical and experimental\\u000a diabetes (i.e. hyperglycaemia, hyperlipidaemia, lowered cell sensitivity to insulin) through the regulation of carbohydrate\\u000a and lipid metabolism and the removal of secondary symptoms of this disease (as e.g.

Anna Goc

2006-01-01

139

Elsholtzia: phytochemistry and biological activities  

PubMed Central

Plants of the genus Elsholtzia (Lamiaceae) have a long history of medicinal use in folk. The phytochemical investigations revealed the presence of flavonoids, phenylpropanoids, terpenoids, and other compounds. Abundant volatile components are also identified. Pure compounds, volatile constituents and crude extracts from the genus exhibited a wide spectrum of in vitro and in vivo pharmacological activities. The aims of this review hopefully provide comprehensive information on the distribution, phytochemistry, volatile components, and pharmacological research of Elsholtzia for exploring the potential and advance researches.

2012-01-01

140

Regulating biological activity in plants with carboxylesterases  

Microsoft Academic Search

Ester hydrolysis dramatically affects the chemical and biological activity of both xenobiotics and endogenous metabolites in plants. By drawing analogies with organic synthesis, de-esterification reveals functional groups which show novel bioactivity and can undergo subsequent chemical modification. Thus, classically parent esters are hydrophobic, membrane permeable precursors of carboxylic acids which show activity as toxins, signalling agents and pathway intermediates. In

Markus C. Gershater; Robert Edwards

2007-01-01

141

Bioremediation of pentachlorophenol-contaminated soil by bioaugmentation using activated soil  

Microsoft Academic Search

The use of an indigenous microbial consortium, pollutant-acclimated and attached to soil particles (activated soil), was\\u000a studied as a bioaugmentation method for the aerobic biodegradation of pentachlorophenol (PCP) in a contaminated soil. A 125-l\\u000a completely mixed soil slurry (10% soil) bioreactor was used to produce the activated soil biomass. Results showed that the\\u000a bioreactor was very effective in producing a

C. Barbeau; L. Deschênes; D. Karamanev; Y. Comeau; R. Samson

1997-01-01

142

Effects of Dimethomorph on Some Enzymatic Activities in Soil  

Microsoft Academic Search

In this study, soil samples (0-20 cm depth)were taken from the same test fields of Henan Institute of Science and Technology in order to determine the effects of dimethomorph on enzymes activities of soils. Basal soil catalase activity (CA) and urease (UA) enzyme activities, the results showed that high dose of dimethomorph introduced into soil had an significant effect on

Yan-bing Wu; Fan-bin Kong; Da-fu Wu; Zhen-min Yan; Zhi-cheng Chen; Tian-fu Deng

2010-01-01

143

Effects of biological weathering on mine soil genesis and fertility  

Microsoft Academic Search

Strip mine spoils derived from overburden rocks of the Pennsylvanian Wise Formation in Buchanan County, Virginia, commonly contain 40% less than 2 mm sized soil material. The physical and chemical properties of these soil materials are related to their rock origin. The soil materials are alkaline due to the presence of carbonates. The principal source of P in the soil

1981-01-01

144

[Chemistry and biological activities of Viburnum odoratissimum].  

PubMed

Viburnum odoratissimum is a folk medicinal plant, it can dredge the meridian passage and contains mainly diterpenes, triterpenes, flavonoids, sesquiterpenes, lignans, coumarin glycosides, etc. Vibsanin-type diterpenoids are the characteristic compounds of V. odoratissimum, and are divided into eleven-membered ring, seven-membered ring, and rearrangement-type. Vibsanin B, vibsanin C and neovibsanin A are the representative compounds of the three subtypes of vibsanin-type diterpenoids respectively. V. odoratissimum has cytotoxic activity, antibacterial activity, fish piscicidal activity and activity of inhibiting the growth of plants, Cytotoxic activity is the main biological activity. PMID:23724642

Liu, Jie; Zhou, Wen-Bin; Cong, Yu-Wen; Liu, Ping

2013-03-01

145

Biological soil crusts on initial soils: organic carbon dynamics and chemistry under temperate climatic conditions  

NASA Astrophysics Data System (ADS)

Numerous studies have been carried out on the community structure and diversity of biological soil crusts (BSCs) as well as their important functions on ecosystem processes. However, the amount of BSC-derived organic carbon (OC) input into soils and its chemical composition under natural conditions has rarely been investigated. In this study, different development stages of algae- and moss-dominated BSCs were investigated on a~natural (<17 yr old BSCs) and experimental sand dune (<4 yr old BSCs) in northeastern Germany. We determined the OC accumulation in BSC-layers and the BSC-derived OC input into the underlying substrates for bulk materials and fractions <63 ?m. The chemical composition of OC was characterized by applying solid-state 13C NMR spectroscopy and analysis of the carbohydrate-C signature.14C contents were used to assess the origin and dynamic of OC in BSCs and underlying substrates. Our results indicated a rapid BSC establishment and development from algae- to moss-dominated BSCs within only 4 yr under this temperate climate. The distribution of BSC types was presumably controlled by the surface stability according to the position in the slope. We found no evidence that soil properties influenced the BSC distribution on both sand dunes. 14C contents clearly indicated the existence of two OC pools in BSCs and substrates, recent BSC-derived OC and lignite-derived "old" OC (biologically refractory). The input of recent BSC-derived OC strongly decreased the mean residence time of total OC. The downward translocation of OC into the underlying substrates was only found for moss-dominated BSCs at the natural sand dune which may accelerate soil formation at these spots. BSC-derived OC mainly comprised O-alkyl C (carbohydrate-C) and to a lesser extent also alkyl C and N-alkyl C in varying compositions. Accumulation of alkyl C was only detected in BSCs at the experimental dune which may induce a~lower water solubility of BSC-derived extracellular polymeric substances when compared to BSCs at the natural sand dune indicating that hydrological effects of BSCs on soils depend on the chemical composition of the extracellular polymeric substances.

Dümig, A.; Veste, M.; Hagedorn, F.; Fischer, T.; Lange, P.; Spröte, R.; Kögel-Knabner, I.

2013-01-01

146

Carbon accumulation by biological soil crusts in relation to relief and sampling depth  

NASA Astrophysics Data System (ADS)

In arid and semiarid ecosystems the soil surface is covered by biological soil crusts (BSC). These BSC are microbial communities of cyanobacteria, lichens and mosses. Due to the photosynthetic activity of these microorganisms, BSC are main carbon contributors to arid ecosystems. The cover is related to ecosystem functions like surface stabilization, water redistribution and nutrient fixation. These functions rely on the microbial community composition of the BSC. Cyanobacteria and cyanolichens excrete exopolysaccharides, which build microaggregates with soil particles. This stabilizes and seals the soil surface. Therefore cyanobacteria and cyanolichen dominated crusts introduce runoff, which affects the distribution of carbon. The total amount of soil organic carbon was determined in relation to the relief position and BSC thickness showing a strong correlation between relief, sampling depth and carbon amounts. At the Arid Ecosystem Research Center (AERC) station of the Nizzana sand dunes (NW Negev, Israel) the dunes and the interdune corridor are covered by BSC up to 80% of the total area. The BSC are composed of a thin topcrust section and a mineral subcrust section. The overall thickness changes in relation to the relief position. Along a dune transect topcrust and subcrust samples were taken and analyzed on their C_org, C_carb, and C_total concentration. The total amount of carbon (g m^-2) was calculated from the carbon concentrations, the BSC bulk density and the sampling depth. Comparing the topcrust and subcrust values of the sampling points the topcrust sections showed 3-4 times higher concentrations of organic carbon than the subcrust sections. The light intensity decreases with soil depth, resulting in a higher biological activity and carbon fixation in the topcrust sections. The subcrust showed relative higher amounts of C_carb contributing to the soil surface stability. Depending on the relief position the total amount of accumulated carbon was 4 times higher at the interdune positions than at the top slope. The data shows a high dependence of total carbon storage by BSC on the relief position and the high importance of the separate crust sections for the accumulation of C_org and C_carb.

Jetter, Stefan; Drahorad, Sylvie; Felix-Henningsen, Peter

2010-05-01

147

Perylenequinones: Isolation, Synthesis, and Biological Activity  

PubMed Central

The perylenequinones are a novel class of natural products characterized by pentacyclic conjugated chromophore giving rise to photoactivity. Potentially useful light-activated biological activity, targeting protein kinase C (PKC), has been identified for several of the natural products. Recently discovered new members of this class of compound, as well as several related phenanthroperylenequinones, are reviewed. Natural product modifications that improve biological profiles, and avenues for the total synthesis of analogs, which are not available from the natural product series, are outlined. An overview of structure/function relationships is provided.

Mulrooey, Carol A.; O'Brien, Erin M.; Morgan, Barbara J.

2013-01-01

148

Soil organic carbon buffers heavy metal contamination on semiarid soils: Effects of different metal threshold levels on soil microbial activity  

Microsoft Academic Search

Traditionally, three threshold levels have been accepted for heavy metal concentrations in agricultural soils, depending on soil pH. The aim of this work was to ascertain how the three threshold values proposed for Cd (3, 6.5, and 12.5 mg kg?1) and Zn (300, 650, and 1300 mg kg?1) really affect soil microbial activity. Two soils, a scrubland soil and a forest soil, differing widely

J. L. Moreno; F. Bastida; M. Ros; T. Hernández; C. García

2009-01-01

149

Soil nematode communities are ecologically more mature beneath late- than early-successional stage biological soil crusts  

USGS Publications Warehouse

Biological soil crusts are key mediators of carbon and nitrogen inputs for arid land soils and often represent a dominant portion of the soil surface cover in arid lands. Free-living soil nematode communities reflect their environment and have been used as biological indicators of soil condition. In this study, we test the hypothesis that nematode communities are successionally more mature beneath well-developed, late-successional stage crusts than immature, early-successional stage crusts. We identified and enumerated nematodes by genus from beneath early- and late-stage crusts from both the Colorado Plateau, Utah (cool, winter rain desert) and Chihuahuan Desert, New Mexico (hot, summer rain desert) at 0-10 and 10-30 cm depths. As hypothesized, nematode abundance, richness, diversity, and successional maturity were greater beneath well-developed crusts than immature crusts. The mechanism of this aboveground-belowground link between biological soil crusts and nematode community composition is likely the increased food, habitat, nutrient inputs, moisture retention, and/or environmental stability provided by late-successional crusts. Canonical correspondence analysis of nematode genera demonstrated that nematode community composition differed greatly between geographic locations that contrast in temperature, precipitation, and soil texture. We found unique assemblages of genera among combinations of location and crust type that reveal a gap in scientific knowledge regarding empirically derived characterization of dominant nematode genera in deserts soils and their functional role in a crust-associated food web. ?? 2006 Elsevier B.V. All rights reserved.

Darby, B. J.; Neher, D. A.; Belnap, J.

2007-01-01

150

Marine Biology Activities. Ocean Related Curriculum Activities.  

ERIC Educational Resources Information Center

|The ocean affects all of our lives. Therefore, awareness of and information about the interconnections between humans and oceans are prerequisites to making sound decisions for the future. Project ORCA (Ocean Related Curriculum Activities) has developed interdisciplinary curriculum materials designed to meet the needs of students and teachers…

Pauls, John

151

Monitoring Biological Activity at Geothermal Power Plants  

Microsoft Academic Search

The economic impact of microbial growth in geothermal power plants has been estimated to be as high as $500,000 annually for a 100 MWe plant. Many methods are available to monitor biological activity at these facilities; however, very few plants have any on-line monitoring program in place. Metal coupon, selective culturing (MPN), total organic carbon (TOC), adenosine triphosphate (ATP), respirometry,

Peter A. Pryfogle

2005-01-01

152

Soil Microbial Activity in Conventional and Organic Agricultural Systems  

Microsoft Academic Search

The aim of this study was to evaluate microbial activity in soils under conventional and organic agricultural system management regimes. Soil samples were collected from plots under conventional management (CNV), organic management (ORG) and native vegetation (AVN). Soil microbial activity and biomass was significantly greater in ORG compared with CNV. Soil bulk density decreased three years after adoption of organic

Ademir S. F. Araújo; Luiz F. C. Leite; Valdinar B. Santos; Romero F. V. Carneiro

2009-01-01

153

The biological activity of silicon carbide whiskers  

SciTech Connect

Size characteristics of SiC whiskers are similar to asbestos and contain potentially carcinogenic long thin fibers. Size distribution suggests that it is highly respirable, with majority of particles having diameters <3.0 [mu]m. Cytotoxic activity of SiC whiskers in cultured cells is [ge] than that of crocidolite asbestos. Inhalation exposures are needed to further delineate the biological activity; while SiC whiskers were as or more cytotoxic than crocidolite, JM Code 100 also displays such activity but results in no increased risk of lung cancer, pulmonary fibrosis or mesothelioma. PRD-166, a coarse continuous glass filament, displays little in vitro biological activity. It is recommended that SiC whiskers be treated as asbestos, and to continue investigating the potential health effects of SiC whiskers, in particular conducting animal experiments with acute and chronic inhalation exposures. 17 refs., 11 tabs., 18 figs.

Johnson, N.F.

1989-01-01

154

Glycosides from Marine Sponges (Porifera, Demospongiae): Structures, Taxonomical Distribution, Biological Activities and Biological Roles  

PubMed Central

Literature data about glycosides from sponges (Porifera, Demospongiae) are reviewed. Structural diversity, biological activities, taxonomic distribution and biological functions of these natural products are discussed.

Kalinin, Vladimir I.; Ivanchina, Natalia V.; Krasokhin, Vladimir B.; Makarieva, Tatyana N.; Stonik, Valentin A.

2012-01-01

155

ECOLOGY AND POPULATION BIOLOGY OF AFLATOXIGENIC FUNGI IN SOIL  

Technology Transfer Automated Retrieval System (TEKTRAN)

Soil serves as a reservoir for Aspergillus flavus and A. parasiticus, fungi that produce carcinogenic aflatoxins in agricultural commodities. Populations in soil are genetically diverse and individual genotypes show a clustered distribution pattern within fields. Surveys over large geographic region...

156

Comparison of methods for measuring soil microbial activity using cotton strips and a respirometer.  

PubMed

In order to develop a method of measuring the level of microbial activity in soil that is suitable for use by farmers, land managers, and other non-scientists, a simple method for determining soil microbial activity was evaluated and compared with two standard techniques. Soils sampled from vegetable farms in south east Queensland were incubated in the laboratory under controlled moisture and temperature conditions. Three methods were used to measure soil microbial activity, a respirometry method and two methods using the cotton strip assay (CSA) technique (image analysis and tensometer). The standard CSA method measured loss of tensile strength over a 35 day incubation period of buried cotton strips using a tensometer. The new CSA technique measured the intensity of staining by microbes using a flatbed scanner to create an image of the cotton strip whose staining percentage was determined using Photoshop software. The respirometry method used the substrate induced respiration rate (SIR) to determine microbial biomass in the soil at day 12 of incubation. The strong correlation between the image analysis method and the tensometer method (r(2)=0.81), a technique used by scientific researchers, suggests that the image analysis method could be used to monitor aspects of soil biological health by general community land-care groups and farmers. The image analysis method uses equipment which is readily available and, while not strongly correlated with more precise measurements of soil biological activity such as microbial biomass (r(2)=0.26), it can detect gross trends in biological health in a soil monitoring program. The CSA method using image analysis was the cheapest technique to measure soil microbial activity. CSA using image analysis can be a valuable tool in conjunction with other simple indicators of soil physical and chemical health such as slaking and pH to monitor soil amelioration or rehabilitation programs. PMID:17376552

Nachimuthu, Gunasekhar; King, Kathleen; Kristiansen, Paul; Lockwood, Peter; Guppy, Chris

2007-02-21

157

Antiradical and Antioxidant Activity of Biologically Active Carboxylic Acids  

Microsoft Academic Search

The antioxidant and antiradical activity of a series of biologically active carboxylic acids were studied, their effectiveness series were constructed, and optimal concentrations for inhibition of active oxygen formation were found. It is shown that the mechanism of the antioxidant action of these acids can be studied by their effect on different stages of oxygen reduction.

V. F. Gromovaya; G. S. Shapoval; I. E. Mironyuk

2002-01-01

158

The influence of biological soil crusts on mineral uptake by associated vascular plants  

USGS Publications Warehouse

Soil surfaces dominated by cyanobacteria and cyanolichens (such as Collema sp.) are widespread in deserts of the world. The influence of these biological soil crusts on the uptake of bioessential elements is reported for the first time for six seed plants of the deserts of Utah. This sample almost doubles the number of species for which the influence of biological soil crusts on mineral uptake of associated vascular plants is known. These new case studies, and others previously published, demonstrate that cyanobacterial or cyanobacteria- Collema crusts significantly alter uptake by plants of many bioessential elements. In studies now available, these crusts always increase the N content of associated seed plants. Uptake of Cu, K, Mg, and Zn is usually (>70% of reported cases) increased in the presence of the biological soil crusts. Soil crusts are generally negatively associated with Fe and P levels in associated seed plant tissue, while plant tissue levels of Ca, Mn, and Na are positively as often as negatively associated with the presence of soil crusts. Increases in bioessential elements in vascular plant tissue from biologically-crusted areas are greatest for short-lived herbs that are rooted primarily within the surface soil, the horizon most influenced by crustal organisms. The mineral content of a deeply rooted shrub (Coleogyne ramosissima) was less influenced by co-occurrence of biological soil crusts.

Harper, K. T.; Belnap, Jayne

2001-01-01

159

Physicochemical and biological quality of soil in hexavalent chromium-contaminated soils as affected by chemical and microbial remediation.  

PubMed

Chemical and microbial methods are the main remediation technologies for chromium-contaminated soil. These technologies have progressed rapidly in recent years; however, there is still a lack of methods for evaluating the chemical and biological quality of soil after different remediation technologies have been applied. In this paper, microbial remediation with indigenous bacteria and chemical remediation with ferrous sulphate were used for the remediation of soils contaminated with Cr(VI) at two levels (80 and 1,276 mg kg(-1)) through a column leaching experiment. After microbial remediation with indigenous bacteria, the average concentration of water-soluble Cr(VI) in the soils was reduced to less than 5.0 mg kg(-1). Soil quality was evaluated based on 11 soil properties and the fuzzy comprehensive assessment method, including fuzzy mathematics and correlative analysis. The chemical fertility quality index was improved by one grade using microbial remediation with indigenous bacteria, and the biological fertility quality index increased by at least a factor of 6. Chemical remediation with ferrous sulphate, however, resulted in lower levels of available phosphorus, dehydrogenase, catalase and polyphenol oxidase. The result showed that microbial remediation with indigenous bacteria was more effective for remedying Cr(VI)-contaminated soils with high pH value than chemical remediation with ferrous sulphate. In addition, the fuzzy comprehensive evaluation method was proven to be a useful tool for monitoring the quality change in chromium-contaminated soils. PMID:23784058

Liao, Yingping; Min, Xiaobo; Yang, Zhihui; Chai, Liyuan; Zhang, Shujuan; Wang, Yangyang

2013-06-20

160

Adsorption, Movement, and Biological Degradation of Large Concentrations of Selected Pesticides in Soils.  

National Technical Information Service (NTIS)

Because of the importance of soil in biologically reducing the quantity and retarding the rate of pollutant movement into groundwater, this laboratory study was initiated to evaluate the adsorption, mobility, and degradation of large concentrations of the...

J. M. Davidson P. S. C. Rao L. T. Ou W. B. Wheeler D. F. Rothwell

1980-01-01

161

Decontaminazione di suoli mediante processi biologici. (Soil decontamination using biological processes (bioremediation)).  

National Technical Information Service (NTIS)

Bioremediation, the use of biological processes to detoxify polluted soils, is not a new technique, but now it is arousing a renewed interest and the practical applications outline that bioremediation is a very promising technique. Microorganisms are the ...

A. R. Sprocati

1994-01-01

162

Biological and physical influences on soil 14CO2 seasonal dynamics in a temperate hardwood forest  

NASA Astrophysics Data System (ADS)

While radiocarbon (14C) abundance in standing stocks of soil carbon has been used to evaluate rates of soil carbon turnover on timescales of several years to centuries, soil-respired 14CO2 measurements are an important tool for identifying more immediate responses to disturbance and climate change. Soil 14CO2 data are often temporally sparse, however, and could be interpreted better with more context for typical seasonal ranges and trends. We report on a semi-high-frequency sampling campaign to distinguish physical and biological drivers of soil 14CO2 at a temperate forest site in Northern Wisconsin, USA. We sampled 14CO2 profiles every three weeks during snow-free months through 2012, in three intact plots and one trenched plot that excluded roots. Respired 14CO2 declined through the summer in intact plots, shifting from an older C composition that contained more bomb 14C, to a younger composition more closely resembling present 14C levels in the atmosphere. In the trenched plot respired 14C was variable but remained comparatively higher than in intact plots, reflecting older bomb-enriched 14C sources. Although respired 14CO2 from intact plots correlated with soil moisture, related analyses did not support a clear cause-and-effect relationship with moisture. The initial decrease in 14CO2 from spring to midsummer could be explained by increases in 14C-deplete root respiration; however, 14CO2 continued to decline in late summer after root activity decreased. We also investigated whether soil moisture impacted vertical partitioning of CO2 production, but found this had little effect on respired 14CO2 because CO2 contained modern bomb-C at depth, even in the trenched plot. This surprising result contrasted with decades to centuries-old pre-bomb CO2 produced in lab incubations of the same soils. Our results suggest that root-derived C and other recent C sources had dominant impacts on 14CO2 in situ, even at depth. We propose that 14CO2 may have declined through late summer in intact plots because of continued microbial turnover of root-derived C, following declines in root respiration. Our results agree with other studies showing large seasonal fluctuations in respired ?14CO2, and suggest root C inputs are an important driver.

Phillips, C. L.; McFarlane, K. J.; Risk, D.; Desai, A. R.

2013-07-01

163

NO gas loss from biologically crusted soils in Canyonlands National Park, Utah  

USGS Publications Warehouse

In this study, we examined N gas loss as nitric oxide (NO) from N-fixing biologically crusted soils in Canyonlands National Park, Utah. We hypothesized that NO gas loss would increase with increasing N fixation potential of the biologically crusted soil. NO fluxes were measured from biologically crusted soils with three levels of N fixation potential (Scytonema-Nostoc-Collema spp. (dark)>Scytonema-Nostoc-Microcoleus spp. (medium)>Microcoleus spp. (light)) from soil cores and field chambers. In both cores and field chambers there was a significant effect of crust type on NO fluxes, but this was highly dependent on season. NO fluxes from field chambers increased with increasing N fixation potential of the biologically crusted soils (dark>medium>light) in the summer months, with no differences in the spring and autumn. Soil chlorophyllasis Type a content (an index of N fixation potential), percent N, and temperature explained 40% of the variability in NO fluxes from our field sites. Estimates of annual NO loss from dark and light crusts was 0.04-0.16 and 0.02-0.11-N/ha/year. Overall, NO gas loss accounts for approximately 3-7% of the N inputs via N fixation in dark and light biologically crusted soils. Land use practices have drastically altered biological soil crusts communities over the past century. Livestock grazing and intensive recreational use of public lands has resulted in a large scale conversion of dark cyanolichen crusts to light cyanobacterial crusts. As a result, changes in biologically crusted soils in arid and semi-arid regions of the western US may subsequently impact regional NO loss. ?? Springer 2005.

Barger, N. N.; Belnap, J.; Ojima, D. S.; Mosier, A.

2005-01-01

164

Long-term impact of acid resin waste deposits on soil quality of forest areas II. Biological indicators.  

PubMed

In this study, we evaluated the effects of two acid resin deposits on the soil microbiota of forest areas by means of biomass, microbial activity-related estimations and simple biological ratios. The determinations carried out included: total DNA yield, basal respiration, intracellular enzyme activities (dehydrogenase and catalase) and extracellular enzyme activities involved in the cycles of C (beta-glucosidase and chitinase), N (protease) and P (acid-phosphatase). The calculated ratios were: total DNA/total N; basal respiration/total DNA; dehydrogenase/total DNA and catalase/total DNA. Total DNA yield was used to estimate soil microbial biomass. Results showed that microbial biomass and activity were severely inhibited in the deposits, whilst resin effects on contaminated zones were variable and site-dependant. Correlation analysis showed no clear effect of contaminants on biomass and activities outside the deposits, but a strong interdependence with natural organic matter related parameters such as total N. In contrast, by using simple ratios we could detect more stressful conditions in terms of organic matter turnover and basal metabolism in contaminated areas compared to their uncontaminated counterparts. These results stress that developed ecosystems such as forests can buffer the effects of pollutants and preserve high functionality via natural attenuation mechanisms, but also that acid resins can be toxic to biological targets negatively affecting soil dynamics. Acid resin deposits can therefore act as contaminant sources adversely altering soil processes and reducing the environmental quality of affected areas despite the solid nature of these wastes. PMID:18768212

Pérez-de-Mora, Alfredo; Madejón, Engracia; Cabrera, Francisco; Buegger, Franz; Fuss, Roland; Pritsch, Karin; Schloter, Michael

2008-09-02

165

Relationships between soil urease activity and other properties of some tropical wetland rice soils  

Microsoft Academic Search

Ten Philippine wetland rice soils differing widely in pH, texture and organic matter were studied to determine relationships between urease activity and other soil properties. Simple correlation analyses of urease activity with soil properties indicated that urease activity was correlated highly significantly with total N (r = 0.91)**, and organic C (r = 0.89**) but was not significantly correlated with

KL Sahrawat

1983-01-01

166

Biological Degradation of Common Pharmaceuticals and Personal Care Products in Soils with High Water Content  

Microsoft Academic Search

Biological degradation rates of six pharmaceuticals and personal care products were examined in soil from a land application\\u000a site and in adjacent soil with no prior history of effluent exposure. Microbial degradation rates were compared over 2 weeks\\u000a under standing water or saturated conditions and draining conditions after having been saturated for 3 days. Biological degradation\\u000a of 17?-estradiol exhibited rapid rates of

Deborah L. Carr; Audra N. Morse; John C. Zak; Todd A. Anderson

2011-01-01

167

Disturbance of biological soil crust increases emergence of exotic vascular plants in California sage scrub  

Microsoft Academic Search

Biological soil crusts (BSCs) are comprised of soil particles, bacteria, cyanobacteria, green algae, microfungi, lichens,\\u000a and bryophytes and confer many ecosystem services in arid and semiarid ecosystems worldwide, including the highly threatened\\u000a California sage scrub (CSS). These services, which include stabilizing the soil surface, can be adversely affected when BSCs\\u000a are disturbed. Using field and greenhouse experiments, we tested the

Rebecca R. Hernandez; Darren R. Sandquist

168

Effect of Forest Fire on Some Physical, Chemical and Biological Properties of Soil in Çanakkale, Turkey  

Microsoft Academic Search

This study was conducted in burned and un-burned forest area in around Lapseki town in Canakkale Province, Turkey in 2002. The objective of this study was to investigate the effect of the forset fire on physical, chemical and biological soil properties two weeks after the fire. According to the results, the mean soil organic carbon value was 7.14% for burned

HUSEYIN EKINCI

169

Application of biological indicators to assess recovery of hydrocarbon impacted soils  

Microsoft Academic Search

Remediation programmes are considered complete when human risk-based criteria are met. These targets are unrelated to the ecological parameters that may be important with regard to future soil uses. As a consequence, there has been a move towards the consideration of biological indicators for hazard assessment in conjunction with the remediation of contaminated soils. This study uses a range of

J. J. C. Dawson; E. J. Godsiffe; I. P. Thompson; T. K. Ralebitso-Senior; K. S. Killham; G. I. Paton

2007-01-01

170

Biologically active compounds from Aphyllophorales (polypore) fungi.  

PubMed

This review describes biologically active natural products isolated from Aphyllophorales, many of which are known as polypores. Polypores are a large group of terrestrial fungi of the phylum Basdiomycota (basidiomycetes), and they along with certain Ascomycota are a major source of pharmacologically active substances. There are about 25 000 species of basidiomycetes, of which about 500 are members of the Aphyllophorales, a polyphyletic group that contains the polypores. Many of these fungi have circumboreal distributions in North America, Europe, and Asia and broad distributions on all inhabited continents and Africa; only a small number of the most common species with the most obvious fruiting bodies (basidiocarps) have been evaluated for biological activity. An estimated 75% of polypore fungi that have been tested show strong antimicrobial activity, and these may constitute a good source for developing new antibiotics. Numerous compounds from these fungi also display antiviral, cytotoxic, and/or antineoplastic activities. Additional important components of this vast arsenal of compounds are polysaccharides derived from the fungal cell walls. These compounds have attracted significant attention in recent years because of their immunomodulatory activities, resulting in antitumor effects. These high molecular weight compounds, often called biological response modifiers (BRM), or immunopotentiators, prevent carcinogenesis, show direct anticancer effects, and prevent tumor metastasis. Some of the protein-bound polysaccharides from polypores and other basidiomycetes have found their way to the market in Japan as anticancer drugs. Finally, numerous compounds with cardiovascular, phytotoxic, immunomodulatory, analgesic, antidiabetic, antioxidant, insecticidal, and nematocidal activities, isolated from polypores, are also presented. In fact many of the fungi mentioned in this paper have long been used in herbal medicine, including polypores such as Ganoderma lucidum (Reishi or Ling Zhi), Laetiporus sulphureus (Chicken-of-the-Woods), Trametes versicolor (Yun Zhi), Grifola umbellata (Zhu Lin), Inonotus obliquus (Chaga), and Wolfiporia cocos (Hoelen). PMID:14987072

Zjawiony, Jordan K

2004-02-01

171

Exploring the biological activities of Echeveria leucotricha  

Microsoft Academic Search

Echeveria leucotricha J. A. Purpus (Crassulaceae) was evaluated for its potential antibacterial, antifungal, antiparasitic, cytotoxic and anti-inflammatory bioactivities. Aerial parts were extracted with hexane, methanol and chloroform, and fractionated accordingly. Biological activity was assessed in vitro against five Gram-positive and four Gram-negative bacteria, four human pathogenic fungi and the protozoan Leishmania donovani. Extracts and fractions showing bioactivities were further investigated for

María G. Martínez Ruiz; Anaximandro Gómez-Velasco; Zaida N. Juárez; Luis R. Hernández; Horacio Bach

2012-01-01

172

[Biologically active substances of preparation avercom].  

PubMed

The preparation avercom created on the basis of ethanol extracts from the biomass of Streptomyces avermitilis UCM Ac-2179, contains an antiparasitic antibiotic avermectin, as well as a complex of biologically active substances: amino acids, lipids, including nonsaturated fatty acids, and phytohormones, particularly: auxins, cytokinins, hybberellins. The above mentioned complex is characterized by nematocidical, phytostimulating and elicitor effect upon plants which has been confirmed with the results of production experiments on the cucumber variety Angelina. PMID:22830191

Beliavskaia, L A; Kozyritskaia, V E; Valagurova, E V; Iutinskaia, G A

173

Perturbational profiling of nanomaterial biologic activity  

PubMed Central

Our understanding of the biologic effects (including toxicity) of nanomaterials is incomplete. In vivo animal studies remain the gold standard; however, widespread testing remains impractical, and the development of in vitro assays that correlate with in vivo activity has proven challenging. Here, we demonstrate the feasibility of analyzing in vitro nanomaterial activity in a generalizable, systematic fashion. We assessed nanoparticle effects in a multidimensional manner, using multiple cell types and multiple assays that reflect different aspects of cellular physiology. Hierarchical clustering of these data identifies nanomaterials with similar patterns of biologic activity across a broad sampling of cellular contexts, as opposed to extrapolating from results of a single in vitro assay. We show that this approach yields robust and detailed structure–activity relationships. Furthermore, a subset of nanoparticles were tested in mice, and nanoparticles with similar activity profiles in vitro exert similar effects on monocyte number in vivo. These data suggest a strategy of multidimensional characterization of nanomaterials in vitro that can inform the design of novel nanomaterials and guide studies of in vivo activity.

Shaw, Stanley Y.; Westly, Elizabeth C.; Pittet, Mikael J.; Subramanian, Aravind; Schreiber, Stuart L.; Weissleder, Ralph

2008-01-01

174

Biological activity and potential remediation involving geotextile landfill leachate filters  

SciTech Connect

The paper presents the results of a biological growth study in geotextile filters used in landfill leachate collection systems. After reviewing the first year's activity, a completely new experimental approach has been taken. Using 100 mm diameter columns for the experimental incubation and flow systems, the effects of six landfill leachates are evaluated. Aerobic and anaerobic states, four different geotextiles, and soil/no soil conditions above the geotextiles are involved in the testing program. The results in 96 individual test columns. Flow data is measured regularly, and over the first six months of evaluation certain trends were observed. For two of the landfill leachates, backflushing has been attempted so as to reinstitute flow. The procedure works well for the geotextile alone while not as well for the geotextile/soil columns. The exception is the nonwoven heat set geotextile. All tests are still ongoing and will be dismantled and further investigated at the end of 12 months exposure time. The experimental setup and procedure has been written up as a tentative ASTM test method and is currently in task group review.

Koerner, G.R.; Koerner, R.M.

1992-01-01

175

Field management effects on soil enzyme activities  

Microsoft Academic Search

There is growing recognition for the need to develop sensitive indicators of soil quality that reflect the effects of land management on soil and assist land managers in promoting long-term sustainability of terrestrial ecosystems. Eleven soil enzymes assays were investigated relative to soil management and soil quality at two study sites. Soils were sampled from the Vegetable Crop Rotation Plots

Anna K. Bandick; Richard P. Dick

1999-01-01

176

Daily dynamics of cellulase activity in arable soils depending on management practices  

NASA Astrophysics Data System (ADS)

The daily dynamics of cellulase activity was studied during 27 days by the cellophane membrane method on soils managed using the conventional high-input farming system (application of mineral fertilizers and pesticides) and the biological conservation farming system (application of organic fertilizers alone) in a microfield experiment. The regular oscillatory dynamics of the cellulase activity were revealed and confirmed by the harmonic (Fourier) analysis. The oscillatory dynamics of the cellulase activity had a self-oscillatory nature and was not directly caused by the disturbing impacts of both the uncontrolled (natural) changes in the temperature and moisture (rainfall) and the controlled ones (the application of different fertilizers). The disturbing impacts affected the oscillation amplitude of the cellulase activity but not the frequency (periods) of the oscillations. The periodic oscillations of the cellulase activity were more significant in the soil under the high-input management compared to the soil under the biological farming system.

Lavrent'eva, E. V.; Semenov, A. M.; Zelenev, V. V.; Chzhun, Yu.; Semenova, E. V.; Semenov, V. M.; Namsaraev, B. B.; van Bruggen, A. H. C.

2009-08-01

177

Nitrous oxide from soil denitrification: factors controlling its biological production  

Microsoft Academic Search

Increasing concentrations of nitrate, nitrite, and molecular oxygen enhanced production of nitrous oxide relative to molecular nitrogen during dentrification in soils. Soil acidity interacted with nitrate to increase the ratio of nitrous oxide to molecular nitrogen. In response to anoxic conditions, nitrous oxide production initially increased but nitrous oxide was then consumed, a pattern which resulted from the sequential synthesis

M. K. Firestone; R. B. Firestone; J. M. Tiedje

1980-01-01

178

A theoretical framework for biological control of soil-borne plant pathogens: Identifying effective strategies  

Microsoft Academic Search

We develop and analyse a flexible compartmental model of the interaction between a plant host, a soil-borne pathogen and a microbial antagonist, for use in optimising biological control. By extracting invasion and persistence thresholds of host, pathogen and biological control agent, performing an equilibrium analysis, and numerical investigation of sensitivity to parameters and initial conditions, we determine criteria for successful

Nik J. Cunniffe; Christopher A. Gilligan

2011-01-01

179

Low intensity ultrasound stimulates biological activity of aerobic activated sludge  

Microsoft Academic Search

This work aims to explore a procedure to improve biological wastewater treatment efficiency using low intensity ultrasound.\\u000a The aerobic activated sludge from a municipal wastewater treatment plant was used as the experimental material. Oxygen uptake\\u000a rate (OUR) of the activated sludge (AS) was determined to indicate the changes of AS activity stimulated by ultrasound at\\u000a 35 kHz for 0–40 min

Hong Liu; Yixin Yan; Wenyan Wang; Yongyong Yu

2007-01-01

180

Soil nutrient and soil enzyme activity at various types of slopes in disturbed area of Xiangjiaba hydropower construction  

Microsoft Academic Search

Taking seven types of slopes in the disturbed area of Xiangjiaba construction as test objects this paper measured their soil pH, soil nutrient and soil enzyme activity. The results showed that the soil at natural forests (NF) was acidic, while the others were weakly alkaline at different degree. Variation of soil nutrients in different slopes is obvious; soil enzyme activity

Dong Xia; Wen-nian Xu; Juan Zhao; Shun-Bo Zhu

2011-01-01

181

Effects of electrokinetic treatment of a heavy metal contaminated soil on soil enzyme activities  

Microsoft Academic Search

There is a growing concern on the potential application of a direct current (DC) electric field to soil for removing contaminants, but little is known about its impact on soil enzyme activities. This study investigated the change of enzyme activities of a heavy metal contaminated soil before and after electrokinetic (EK) treatments at lab-scale and the mechanisms of EK treatment

Long Cang; Dong-Mei Zhou; Quan-Ying Wang; Dan-Ya Wu

2009-01-01

182

Arbuscular mycorrhizas and biological control of soil-borne plant pathogens – an overview of the mechanisms involved  

Microsoft Academic Search

Biological control of plant pathogens is currently accepted as a key practice in sustainable agriculture because it is based\\u000a on the management of a natural resource, i.e. certain rhizosphere organisms, common components of ecosystems, known to develop\\u000a antagonistic activities against harmful organisms (bacteria, fungi, nematodes etc.). Arbuscular mycorrhizal (AM) associations\\u000a have been shown to reduce damage caused by soil-borne plant

C. Azcón-Aguilar; J. M. Barea

1997-01-01

183

Biological soil crust distribution is related to patterns of fragmentation and landuse in a dryland agricultural landscape of southern Australia  

Microsoft Academic Search

The dryland agricultural landscape of north-west Victoria, Australia, includes isolated remnants of eucalypt woodland that\\u000a are exposed to ongoing disturbance from sheep grazing and cropping activity. Biological soil crusts are a functionally important\\u000a feature of these woodland communities. We used a modern form of regression (boosted regression tree (BRT) models) to investigate\\u000a relationships between crust abundance and environmental and landscape

Cassia F. Read; David H. Duncan; Peter A. Vesk; Jane Elith

2008-01-01

184

Modification of soil microbial activity and several hydrolases in a forest soil artificially contaminated with copper  

NASA Astrophysics Data System (ADS)

Soils have long been exposed to the adverse effects of human activities, which negatively affect soil biological activity. As a result of their functions and ubiquitous presence microorganisms can serve as environmental indicators of soil pollution. Some features of soil microorganisms, such as the microbial biomass size, respiration rate, and enzyme activity are often used as bioindicators of the ecotoxicity of heavy metals. Although copper is essential for microorganisms, excessive concentrations have a negative influence on processes mediated by microorganisms. In this study we measured the response of some microbial indicators to Cu pollution in a forest soil, with the aim of evaluating their potential for predicting Cu contamination. Samples of an Ah horizon from a forest soil under oakwood vegetation (Quercus robur L.) were contaminated in the laboratory with copper added at different doses (0, 120, 360, 1080 and 3240 mg kg-1) as CuCl2×2H2O. The soil samples were kept for 7 days at 25 °C and at a moisture content corresponding to the water holding capacity, and thereafter were analysed for carbon and nitrogen mineralization capacity, microbial biomass C, seed germination and root elongation tests, and for urease, phosphomonoesterase, catalase and ß-glucosidase activities. In addition, carbon mineralization kinetics were studied, by plotting the log of residual C against incubation time, and the metabolic coefficient, qCO2, was estimated. Both organic carbon and nitrogen mineralization were lower in polluted samples, with the greatest decrease observed in the sample contaminated with 1080 mg kg-1. In all samples carbon mineralization followed first order kinetics; the C mineralization constant was lower in contaminated than in uncontaminated samples and, in general, decreased with increasing doses of copper. Moreover, it appears that copper contamination not only reduced the N mineralization capacity, but also modified the N mineralization process, since in the contaminated samples all of the inorganic nitrogen was present as ammonium, probably because of inhibition of nitrification. There was a marked decrease in biomass-C with addition of copper, and the decrease was more acute at intermediate doses (average decrease, 73%). Despite the decreases in microbial biomass and mineralized C, the value of qCO2 increased after the addition of copper. Urease activity was strongly affected by the presence of copper and the decrease was proportional to the dose; the activity at the highest dose was only 96% of that in the uncontaminated sample. Phosphomonoesterase activity was also affected by addition of copper; the reduction in activity was less than for urease and the greatest reduction was observed for the dose of 1080 mg kg-1 of copper. Catalase activity was affected by the contamination, but no clear trend was observed in relation to the dose of copper. ß-glucosidase was scarcely modified by the contamination but an increase in activity was observed at the highest dose of copper. Seed germination was not affected by copper contamination, since it only showed a clear decrease for the sample contaminated with the highest dose of copper, while root elongation decreased sharply with doses higher than 120 mg kg-1 of copper. The combined germination-elongation index followed a similar pattern to that of root elongation. For all investigated properties showing a reduction of more than 50%, the response to copper contamination was fitted to a sigmoidal dose-response model, in order to estimate the ED50 values. The ED50 values were calculated for microbial biomass, urease, root elongation and germination-elongation index, and similar values were obtained, ranging from 340 to 405 mg kg-1 Cu. The ED50 values may therefore provide a good estimation of soil deterioration.

Bellas, Rosa; Leirós, M? Carmen; Gil-Sotres, Fernando; Trasar-Cepeda, Carmen

2010-05-01

185

Activity of Soil Dehydrogenases, Urease, and Acid and Alkaline Phosphatases in Soil Polluted with Petroleum  

Microsoft Academic Search

This study was undertaken to (1) determine the effects of petroleum pollution on changes in the biochemical properties of soil and (2) demonstrate whether the application of compost, bentonite, and calcium oxide is likely to restore biological balance. Petroleum soil pollution at a dose ranging from 2.5 to 10 cm\\/kg disturbed the biochemical balance as evidenced by inhibition of the

Jadwiga Wyszkowska; Miros?aw Wyszkowski

2010-01-01

186

Intrinsic and induced isoproturon catabolic activity in dissimilar soils and soils under dissimilar land use.  

PubMed

The catabolic activity with respect to the systemic herbicide isoproturon was determined in soil samples by (14)C-radiorespirometry. The first experiment assessed levels of intrinsic catabolic activity in soil samples that represented three dissimilar soil series under arable cultivation. Results showed average extents of isoproturon mineralisation (after 240 h assay time) in the three soil series to be low. A second experiment assessed the impact of addition of isoproturon (0.05 microg kg(-1)) into these soils on the levels of catabolic activity following 28 days of incubation. Increased catabolic activity was observed in all three soils. A third experiment assessed levels of intrinsic catabolic activity in soil samples representing a single soil series managed under either conventional agricultural practice (including the use of isoproturon) or organic farming practice (with no use of isoproturon). Results showed higher (and more consistent) levels of isoproturon mineralisation in the soil samples collected from conventional land use. The final experiment assessed the impact of isoproturon addition on the levels of inducible catabolic activity in these soils. The results showed no significant difference in the case of the conventional farm soil samples while the induction of catabolic activity in the organic farm soil samples was significant. PMID:15519720

Reid, Brian J; Papanikolaou, Niki D; Wilcox, Ronah K

2005-02-01

187

Biologically active Mannich bases derived from nitroxoline.  

PubMed

A series of compounds with various basic side chains were derived from 5-nitro-8-hydroxyquinoline (nitroxoline). Aminomethylation of nitroxoline led exclusively to the formation of o-substituted phenolic Mannich bases. Depending on the kind of the primary or secondary amine participating in the Mannich reaction differently substituted compounds were prepared in order to study the influence of the basic side chain on their biological activity. The compound with N-bis(2-hydroxyethyl)amino group exhibited the highest mitodepressant activity determined in a phyto test on Lepidium sativum L. Preliminary test for antibacterial and antifungal activities using standard test microorganisms indicate rather strong antimicrobial properties of several synthesized compounds. PMID:7433493

Movrin, M; Maysinger, D; Marok, E

1980-08-01

188

Biological activities of isatin and its derivatives.  

PubMed

Isatin is an endogenous compound identified in humans that possesses a wide range of biological activities. Isatin has anxiogenic, sedative, anticonvulsant activities and acts as a potent antagonist on atrial natriuretic peptide receptors in vitro. A series of p-substituted isatin semicarbazones have shown anticonvulsant activity in MES, scPTZ and scSTY tests. Various isatin-N-Mannich bases of isatin-3-thiosemicarbazones have shown antiviral and tuberculostatic activity. Methisazone is an effective compound against variola and vaccinia viruses. The N-dimethyl and morpholino derivative of 5-methyl isatin and trimethoprim exhibited an EC50 of more than 4.3 and 17.7 mg mL(-1), respectively. Isatin (3-o-nitrophenyl) hydrazone has shown activity against Walker carcinoma-256. Various substituted indolinones showed antitubercular activity against M. tuberculosis H37Rv with MIC ranging from 10-20 microg mL(-1). Isatin derivatives of Mannich bases had fibrinolytic, muscle relaxant, antiallergic, immunosuppressant, and antithrombotic activity. Isatin showed cardioinhibitory effect on frog heart, and hypotensive, respiratory depression and antidiuretic effects. PMID:15907222

Pandeya, Surendra Nath; Smitha, Sivakumar; Jyoti, Mayank; Sridhar, Seshaiah Krishnan

2005-03-01

189

Copper activity in soil solutions of calcareous soils  

Microsoft Academic Search

Copper partitioning was studied in seven calcareous soils at moisture content corresponding to 1.2 times the field moisture content (soil water potential 7.84J kg?1). Copper retention was accompanied by the release in soil solution of Ca2+, Mg2+, Na+, and H+, and the total amount of these cations released was 0.8 to 1.09 times the amount of Cu sorbed (molc:molc). The

Alexander A. Ponizovsky; Herbert E. Allen; Amanda J. Ackerman

2007-01-01

190

Biological Activities of Polyphenols from Grapes  

PubMed Central

The dietary consumption of grape and its products is associated with a lower incidence of degenerative diseases such as cardiovascular disease and certain types of cancers. Most recent interest has focused on the bioactive phenolic compounds in grape. Anthocyanins, flavanols, flavonols and resveratrol are the most important grape polyphenols because they possess many biological activities, such as antioxidant, cardioprotective, anticancer, anti-inflammation, antiaging and antimicrobial properties. This review summarizes current knowledge on the bioactivities of grape phenolics. The extraction, isolation and identification methods of polyphenols from grape as well as their bioavailability and potential toxicity also are included.

Xia, En-Qin; Deng, Gui-Fang; Guo, Ya-Jun; Li, Hua-Bin

2010-01-01

191

Elucidating the microbial resuscitation cascade in biological soil crusts following a simulated rain event.  

PubMed

Biological soil crusts (biocrusts) are photosynthetic mats formed through an association of prokaryotic and eukaryotic microorganisms with soil particles. Biocrusts are found in virtually any terrestrial ecosystem where vascular plant coverage is abiotically limited, with drylands comprising the primary habitat for them. We studied the dynamics of the active bacterial community in two biocrusts from an arid and a hyperarid region in the Negev Desert, Israel, under light-oxic and dark-anoxic incubation conditions after simulated rainfall. We used H2 (18) O for hydrating the crusts and analysed the bacterial community in the upper and lower parts of the biocrust using an RNA-stable isotope probing approach coupled with 454-pyrosequencing. In both biocrusts, two distinct bacterial communities developed under each incubation condition. The active anaerobic communities were initially dominated by members of the order Bacillales which were later replaced by Clostridiales. The aerobic communities on the other hand were dominated by Sphingobacteriales and several Alphaproteobacteria (Rhizobiales, Rhodobacterales, Rhodospirillales and Rubrobacteriales). Actinomycetales were the dominant bacterial order in the dry crusts but quickly collapsed and accounted for

Angel, Roey; Conrad, Ralf

2013-05-06

192

Soil microbial activity and structure in mineralized terranes of the Western US  

NASA Astrophysics Data System (ADS)

Mineralized terranes (areas enriched in metal-bearing minerals) occur throughout the Western US, and are characterized by highly variable soil trace metal concentrations across small spatial scales. Assuming that non-lithologic (extrinsic) soil forming factors are relatively constant between mineralized and unmineralized zones, these mineralized areas allowed us to evaluate the effect of lithology on soil microbial activity. We established the following study sites: 1) sage-grassland on a Mo/Cu deposit (Battle Mountain, NV); 2) pine-chaparral on Ni/Cr bearing rocks (Chinese Camp, CA); and 3) two pine woodland sites on acid-sulfate altered rocks (Reno, NV; Bridgeport, CA). Microbial, physical and chemical measurements were performed on soils from undisturbed mineralized areas and adjacent unmineralized areas to determine baseline conditions for comparison to sites disturbed by mining. A host of abiotic soil parameters, along with bioavailable (diethylenetriaminepentaacetic acid (DTPA)-extractable) and total metals, were measured to examine their correlation with the following measures of microbial activity: enzyme assays (arylsulfatase, phosphatase, fluorescein diacetate hydrolysis), C/N mineralization potential, C substrate utilization (Biolog Ecoplate), and microbial biomass and community structure (phospholipid fatty acid analysis). Within the Battle Mountain study area, both microbial activity and structure were statistically similar between mineralized and unmineralized soils. Nutrient and metal concentrations were also similar; the only differences being higher Cu and lower P in the mineralized soils. Within the Chinese Camp study area, soil organic carbon and total nitrogen concentrations were similar between the serpentine (Ni/Cr bearing) and adjacent andesite soils, while differences were noted for other nutrients (S, P, Ca, Mg). For the serpentine soils, Co, Fe, Mn, and Ni showed the strongest correlations with microbial activity, where Cr, Mn showed the strongest correlations in the andesite soils. Measures of microbial activity were statistically similar, except for arylsulfatase and Biolog C substrate utilization, which were greater in the andesite soils. Biolog substrate utilization richness was greater for the andesite soils, which also showed greater fungal biomass compared to the serpentine soils. In the acid sulfate systems, most measures of microbial activity were reduced in the acid sulfate soils compared to the adjacent andesite soils. Lower pH and P, and greater Al concentrations in the acid sulfate soils are potential inhibitors of microbial activity, while greater concentrations of inorganic N suggest that N is not limiting in the acid sulfate soils. Biolog substrate utilization richness was much lower in the acid sulfate soils, which also exhibited a greater proportion of polymer and carbohydrate use compared to the andesite soils. Impacts on microbial activity and microbial community structure are depend on a combination of trace metal and nutrient concentrations within a given mineralization type. Improving our understanding of biotic/abiotic relationships in undisturbed systems should increase our understanding of these relationships in areas disturbed by mining.

Blecker, S. W.; Stillings, L. L.; Decrappeo, N.; Ippolito, J.

2009-12-01

193

Changes and recovery of soil bacterial communities influenced by biological soil disinfestation as compared with chloropicrin-treatment.  

PubMed

Soil bacterial composition, as influenced by biological soil disinfestation (BSD) associated with biomass incorporation was investigated to observe the effects of the treatment on the changes and recovery of the microbial community in a commercial greenhouse setting. Chloropicrin (CP) was also used for soil disinfestation to compare with the effects of BSD. The fusarium wilt disease incidence of spinach cultivated in the BSD- and CP-treated plots was reduced as compared with that in the untreated control plots, showing effectiveness of both methods to suppress the disease. The clone library analyses based on 16S rRNA gene sequences showed that members of the Firmicutes became dominant in the soil bacterial community after the BSD-treatment. Clone groups related to the species in the class Clostridia, such as Clostridium saccharobutylicum, Clostridium tetanomorphum, Clostridium cylindrosporum, Oxobacter pfennigii, etc., as well as Bacillus niacini in the class Bacilli were recognized as the most dominant members in the community. For the CP-treated soil, clones affiliated with the Bacilli related to acid-tolerant or thermophilic bacteria such as Tuberibacillus calidus, Sporolactobacillus laevolacticus, Pullulanibacillus naganoensis, Alicyclobacillus pomorum, etc. were detected as the major groups. The clone library analysis for the soil samples collected after spinach cultivation revealed that most of bacterial groups present in the original soil belonging to the phyla Proteobacteria, Acidobacteria, Bacteroidetes, Gemmatimonadetes, Planctomycetes, TM7, etc. were recovered in the BSD-treated soil. For the CP-treated soil, the recovery of the bacterial groups belonging to the above phyla was also noted, but some major clone groups recognized in the original soil did not recover fully. PMID:23958081

Mowlick, Subrata; Inoue, Takashi; Takehara, Toshiaki; Kaku, Nobuo; Ueki, Katsuji; Ueki, Atsuko

2013-08-17

194

Milk Inhibits the Biological Activity of Ricin  

PubMed Central

Ricin is a highly toxic protein produced by the castor plant Ricinus communis. The toxin is relatively easy to isolate and can be used as a biological weapon. There is great interest in identifying effective inhibitors for ricin. In this study, we demonstrated by three independent assays that a component of reconstituted powdered milk has a high binding affinity to ricin. We discovered that milk can competitively bind to and reduce the amount of toxin available to asialofetuin type II, which is used as a model to study the binding of ricin to galactose cell-surface receptors. Milk also removes ricin bound to the microtiter plate. In parallel experiments, we demonstrated by activity assay and by immuno-PCR that milk can bind competitively to 1 ng/ml ricin, reducing the amount of toxin uptake by the cells, and thus inhibit the biological activity of ricin. The inhibitory effect of milk on ricin activity in Vero cells was at the same level as by anti-ricin antibodies. We also found that (a) milk did not inhibit ricin at concentrations of 10 or 100 ng/ml; (b) autoclaving 10 and 100 ng/ml ricin in DMEM at 121 °C for 30 min completely abolished activity; and (c) milk did not affect the activity of another ribosome inactivating protein, Shiga toxin type 2 (Stx2), produced by pathogenic Escherichia coli O157:H7. Unlike ricin, which is internalized into the cells via a galactose-binding site, Stx2 is internalized through the cell surface receptor glycolipid globotriasylceramides Gb3 and Gb4. These observations suggest that ricin toxicity may possibly be reduced at room temperature by a widely consumed natural liquid food.

Rasooly, Reuven; He, Xiaohua; Friedman, Mendel

2012-01-01

195

NASA's Soil Moisture Active Passive (SMAP) observatory  

NASA Astrophysics Data System (ADS)

The Soil Moisture Active Passive (SMAP) mission, one of the first-tier missions recommended by the 2007 U.S. National Research Council Committee on Earth Science and Applications from Space, was confirmed in May 2012 by NASA to proceed into Implementation Phase (Phase C) with a planned launch in October 2014. SMAP will produce high-resolution and accurate global maps of soil moisture and its freeze/thaw state using data from a non-imaging synthetic aperture radar and a radiometer, both operating at L-band. Major challenges addressed by the observatory design include: (1) achieving global coverage every 2-3 days with a single observatory; (2) producing both high resolution and high accuracy soil moisture data, including through moderate vegetation; (3) using a mesh reflector antenna for L-band radiometry; (4) minimizing science data loss from terrestrial L-band radio frequency interference; (5) designing fault protection that also minimizes science data loss; (6) adapting planetary heritage avionics to meet SMAP's unique application and data volume needs; (7) ensuring observatory electromagnetic compatibility to avoid degrading science; (8) controlling a large spinning instrument with a small spacecraft; and (9) accommodating launch vehicle selection late in the observatory's development lifecycle.

Kellogg, K.; Thurman, S.; Edelstein, W.; Spencer, M.; Chen, Gun-Shing; Underwood, M.; Njoku, E.; Goodman, S.; Jai, Benhan

196

Comparison of CLPP and enzyme activity assay for functional characterization of bacterial soil communities  

Microsoft Academic Search

Background, Aims and Scope  Functional characterization of soil microbial communities by the use of BIOLOG GN microtiter plates was compared with an optimized\\u000a assay of measuring the enzymatic activity of bacterial associated enzymes. Since the first use of BIOLOG GN microtiter plates\\u000a for characterization of environmental microorganisms, this Community Level Physiological Profile (CLPP) has been widely used\\u000a and is today routinely

Anne Winding; Niels Bohse Hendriksen

2007-01-01

197

Diverse biological activities of healthy foods.  

PubMed

Diverse biological activities of 7 healthy foods [powdered pine needle, citrate-fermented sesame, powdered coffee, royal jelly, propolis, pollen and white sesame oil (extracted by super critical state (40 degrees C, 350 atmospheric pressure))] were investigated. The pine needle, sesame and powdered coffee was also extracted successively by ethanol and hot water, and lyophilized. The pine needle and coffee extracts, and propolis showed higher in vitro cytotoxic, bactericidal and oxidation activity, as compared with other 4 lipophilic healthy foods. However, propolis showed slightly lower, but significant cytotoxic and bactericidal activity with much reduced oxidation potential. ESR spectroscopy demonstrated that the cytotoxic activity of these extracts was closely related to their radical generation and O2- scavenging activities. Healthy food components may have both pro-oxidant and anti-oxidant properties. Pre-treatment of mice with pine needle, sesame or powdered coffee extract significantly reduced the lethality of bacterial infection, possibly due to their host-mediated action. These extracts failed to reduce the cytophatic effect of HIV-1 (human immunodeficiency virus) infection in MT-4 cells. No apparent acute toxicity was detected in mice by oral administration of 10 g/kg of these extracts. This data suggest the medicinal efficacy of healthy foods. PMID:11286123

Kobayashi, N; Unten, S; Kakuta, H; Komatsu, N; Fujimaki, M; Satoh, K; Aratsu, C; Nakashima, H; Kikuchi, H; Ochiai, K; Sakagami, H

198

BIOLOGICALLY-MEDIATED REMOVAL AND RECOVERY OF PLUTONIUM FROM CONTAMINATED SOIL  

SciTech Connect

An innovative biological treatment technology successfully reduced plutonium concentration in soil from the Nevada Test Site (NTS) by over 80%. The final volume of plutonium-contaminated material that required disposal was reduced by over 90%. These results, achieved by an independent testing laboratory, confirm the results reported previously using NTS soil. In the previous test a 2530-gram sample of soil (350 to 400 pCi/g Pu) resulted in production of 131 grams of sludge (6,320 pCi/ g Pu) and a treated soil containing 72 pCi/g of Pu. The technology is based on the biological acidification of the soil and subsequent removal of the plutonium and other dissolved metals by a low volume, low energy water leaching process. The leachate is treated in a sulfate-reducing bioreactor to precipitate the metals as metal sulfides. Water may be recycled as process water or disposed since the treatment process removes over 99% of the dissolved metals including plutonium from the water. The plutonium is contained as a stable sludge that can be containerized for final disposal. Full-scale process costs have been developed which employ widely used treatment technologies such as aerated soil piles (biopiles) and bioreactors. The process costs were less than $10 per cubic foot, which were 40 to 50% lower than the baseline costs for the treatment of the NTS soil. The equipment and materials for water and sludge treatment and soil handling are commercially available.

Jerger, Douglas E., Ph.D.,; Alperin, Edward S., QEP,; Holmes, Robert G., Ph.D.

2003-02-27

199

Proteomic profiling: a novel approach to understanding the biological causes of soil water repellency  

NASA Astrophysics Data System (ADS)

Soil water repellency is a common phenomenon affecting a wide range of soil and land use types in different climates and is considered "the norm rather than the exception with its degree being variable". In all but the most severe cases, soil water repellency is transient with soils wetting eventually after prolonged wet weather and returning, when soil moisture content falls below the critical value. Despite the far-reaching environmental and (agro-)economic consequences, the fundamental biological causes of soil water repellency and its transient behaviour remain poorly understood. It is widely accepted that soil water repellency is caused by organic compounds coating soil particle surfaces. This reduces the particle's surface tension to values lower than that of water, which, as a net effect, inhibits the intrusion of liquid water into the soil pore space. Microbial as well as plant-derived substances have been implicated as sources of these organic materials, while some microbes have also been identified as degraders and/or emulsifiers of hydrophobic compounds. Common hydrophobic compounds and metabolites (e.g. alkanes and fatty acids) have been isolated from both wettable and water repellent soils in similar amounts indicating that their relevance is ambiguous. Even greater uncertainty exists about the role of soil micro-organisms in the development, reduction and temporal variability of soil water repellency. Importantly, certain filamentous fungi and actinomycete bacteria are able to render their hydrophilic cell surface hydrophobic, for example, during spore formation and hyphal foraging through air-containing pores in soil, by producing extracellular hydrophobic proteins. Beyond their own cell surface, the extracellular proteins can form highly recalcitrant hydrophobic surfaces on the hydrophilic side of amphiphilic, i.e. air-water or soil particle, interfaces. Remarkably, the proteins from fungi can also adhere to hydrophobic surfaces under drying conditions rendering them hydrophilic. The dynamics of production of these proteins and the formation of these hydrophobic protein surfaces in soils are not known. Other, yet unknown, proteins may also contribute to development, reduction and temporal variability of soil water repellency. Here we present the first steps of a new NERC funded project aimed at exploring the relationship between the presence and/or absence of (hydrophobic) protein and soil water repellency. It involves isolation and characterisation of hydrophobic protein and the temporal metaproteomic profiles in UK grassland and dune soils with varying degrees of water repellency. This contributes to identifying the proteomic dynamics, which may influence soil hydrology and structure, and ultimately the ability of soils to absorb water, support biomass growth, store carbon, and to capture and degrade pollutants.

van Keulen, Geertje; Doerr, Stefan H.; Urbanek, Emilia; Jones, Alun; Dudley, Ed

2010-05-01

200

AhR agonist and genotoxicant bioavailability in a PAH-contaminated soil undergoing biological treatment  

Microsoft Academic Search

Background, aim, and scope  Degradation of the 16 US EPA priority PAHs in soil subjected to bioremediation is often achieved. However, the PAH loss is\\u000a not always followed by a reduction in soil toxicity. For instance, bioanalytical testing of such soil using the chemical-activated\\u000a luciferase gene expression (CALUX) assay, measuring the combined effect of all Ah receptor (AhR) activating compounds, occasionally

Erika Andersson; Anna Rotander; Thomas von Kronhelm; Anna Berggren; Per Ivarsson; Henner Hollert; Magnus Engwall

2009-01-01

201

Isolation of maize soil and rhizosphere bacteria with antagonistic activity against Aspergillus flavus and Fusarium verticillioides  

Technology Transfer Automated Retrieval System (TEKTRAN)

Bacterial isolates from Mississippi maize field soil and maize rhizosphere samples were evaluated for their potential as biological control agents against Aspergillus flavus and Fusarium verticillioides. Isolated strains were screened for antagonistic activities in liquid co-culture against A. flav...

202

Soil properties and N application effects on microbial activities in two winter wheat cropping systems  

Microsoft Academic Search

The application of mineral N fertilizers may influence biologically mediated processes that are important in nutrient transformations and availability. This study was conducted to assess the effect of N application on microbial activities in irrigated and non-irrigated winter wheat systems. Carbon decomposition and microbial biomass C in soils with three N application rates (0, 150, and 300 kg N ha -1

Fayez Raiesi

2004-01-01

203

Methods and compositions comprising Trichoderma atroviride for the biological control of soil borne plant pathogens and promoting plant growth  

US Patent & Trademark Office Database

The present invention relates to Trichoderma atroviride strains and their use as biological control agents or plant growth promoters. Methods and compositions for biological control of soil borne plant pathogens, and increasing plant yield using T. atroviride are also provided.

2013-03-12

204

Biological Soil Crusts of the Subalpine, Alpine, and Nival Areas in the Alps  

Microsoft Academic Search

\\u000a In the Alps, a relatively large amount of landscape occurs in the subalpine, alpine, and nival zones. In these zones, orographic\\u000a and climatic conditions result in many areas with poorly-developed vascular vegetation. Abundant biological soil communities\\u000a colonize the gaps between the plants. The most outstanding soil-crust development is found in windswept places of the alpine\\u000a and nival zones, and on

R. Türk; G. Gärtner

205

Effects of weed management practices on orchard soil biological and fertility properties in southeastern China  

Microsoft Academic Search

Weed management practices on soil biological and fertility properties were studied in a subtropical citrus orchard situated at Changshan County (28°54?N, 118°30?E) in Zhejiang Province, China. Three weed management practices were chemical control plus tillage (herbicide), tillage alone (plowed) and mowing plus tillage (mowed). No significant differences in microbial biomass carbon (MBC), soil organic matter (SOM) or total nitrogen (TN)

Yisong Yang; Han Wang; Jianjun Tang; Xin Chen

2007-01-01

206

Effects of afforestation on phosphorus dynamics and biological properties in a New Zealand grassland soil  

Microsoft Academic Search

Selected chemical, biochemical and biological properties of mineral soil (0–30 cm) were measured under a 19 year old forest\\u000a stand (mixture of Pinus ponderosa and Pinus nigra) and adjacent unimproved grassland at a site in South Island, New Zealand. The effects of afforestation on soil properties\\u000a were confined to the 0–10 cm layer, which reflected the distribution of fine roots

C. R. Chen; L. M. Condron; M. R. Davis; R. R. Sherlock

2000-01-01

207

Automated Robotic Assay of Phosphomonoesterase Activity in Soils  

Microsoft Academic Search

Phosphorus cycling in most ecosystems is dependent on plant and microbiologically derived phosphatase enzymes, and available P limits both microbial and plant growth. Measurements of enzymes in soil systems are often time-consuming and labor intensive. In this study, we examined phosphomonoesterase activity in soils using a Zymark XP laboratory robotic system for soil handling, solvent addition and exchange, filtration, incubation,

M. J. Sadowsky; W. C. Koskinen; J. Seebinger; B. L. Barber; E. Kandeler

2006-01-01

208

Accommodating Students with Disabilities in Soil Science Activities  

ERIC Educational Resources Information Center

|Soil science education is lacking in terms of accommodations for persons with disabilities. Individuals with disabilities are often excluded from soil science activities in school, and from soil science careers. GLOBE (Global Learning Observations to Benefit the Environment) is a worldwide, hands-on primary and secondary school-based education…

Langley-Turnbaugh, S. J.; Murphy, Kate; Levin, E.

2004-01-01

209

Modeling large scale cohesive sediment transport by including biological activity  

Microsoft Academic Search

Biological activity is known to have significant influence on the dynamics of cohesive sediment on a small spatial and temporal scale. In this study we aim to understand the large scale effects of biological activity. These large scale effects could be of great importance for the conservation and management schemes of different estuaries. Hereto, effects of biology are quantitatively incorporated

B. W. Borsje; S. J. M. H. Hulscher

2007-01-01

210

Biological activities of Synanceja horrida (stonefish) venom.  

PubMed

Some biological and neurochemical properties of the venom of stonefish (Syanceja horrida) were investigated. The venom exhibited oedema-inducing, haemolytic, hyaluronidase, thrombin-like, alkaline phosphomonoesterase, 5' nucleotidase, acetylcholinesterase, phosphodiesterase, arginine esterase, and arginine amidase activities. Recalcification clotting time, prothrombin, and kaolin-cephalin clotting times were increased 1.7-2.3- and 2.4-fold respectively. The LD50 (i.v. mouse) was 300 micrograms/Kg. Its effects on uptake and stimulation of neurotransmitter synthesis and release were observed in rat brain synaptosomes. In the presence of 100 micrograms venom, uptake of [methyl-3H] choline in rat brain synaptosomes was inhibited 70%, while that of 4-amino-n-[U-14C] butyric acid was inhibited 20%. The toxin also stimulated the release of [3H]-acetylcholine from the synaptosomes. PMID:1364268

Khoo, H E; Yuen, R; Poh, C H; Tan, C H

1992-01-01

211

Near infrared spectra are more sensitive to land use changes than physical, chemical and biological soil properties  

NASA Astrophysics Data System (ADS)

We studied the sensibility of the near infrared spectra (NIR) of soils to the changes caused by land use, and we compared with the sensibility of different sets of physical, chemical and biological soil properties. For this purpose, we selected three land uses, constituted by forest, almond trees orchards, and orchards abandoned between 10 and 15 years previously to sampling. Sampling was carried out in four different locations from the province of Alicante (SE Spain). We used discriminant analysis (DA) using different sets of soil properties. The different sets tested in this study using DA were: (1) physical and chemical properties (organic carbon, total nitrogen, available phosphorus, pH, electrical conductivity, cation exchange capacity, aggregate stability, water holding capacity, and available Ca, Mg, K and Na), (2) biochemical properties (microbial biomass carbon, basal respiration and urease, phosphatase and ?-glucosidase activities), (3) phospholipids fatty acids (PLFAs), (4) physical, chemical and biochemical properties (all properties of the previous sets), and (5) the NIR spectra of soils (scores of the principal components). In general, all sets of properties were sensible to land use. This was observed in the DAs by the separation (more or less clear) of samples in groups defined by land use (irrespective of site). The worst results were obtained using soil physical and chemical properties. The combination of physical, chemical and biological properties enhanced the separation of samples in groups, indicating higher sensibility. It is accepted than combination of properties of different nature is more effective to evaluate the soil quality. The microbial community structure (PLFAs) was highly sensible to the land use, grouping correctly the 100% of the samples according with the land use. The NIR spectra were also sensitive to land use. The scores of the first 5 components, which explained 99.97% of the variance, grouped correctly the 85% of the soil samples by land use, but were unable to group correctly the 100% of the samples. Surprisingly, when the scarce variance presents in components 5 to 40 was also used, the 100% of the samples were grouped by land use, as it was observed with PLFAs. But PLFAs analysis is expensive and time-consuming (some weeks). In contrast, only some minutes are needed for the obtainment of the NIR spectra. Additionally, no chemicals are need, decreasing the costs. The NIR spectrum of a soil contains relevant information about physical, chemical and biochemical properties. NIR spectrum could be considered as an integrated vision of soil quality, and as consequence offers an integrated vision of perturbations. Thus, NIR spectroscopy could be used as tool to monitoring soil quality in large areas. Acknowledgements: Authors acknowledge to "Bancaja-UMH" for the financial support of the project "NIRPRO"

Guerrero, C.; Zornoza, R.; Mataix-Solera, J.; Mataix-Beneyto, J.; Scow, K.

2009-04-01

212

Biological remediation of polynuclear aromatic hydrocarbon contaminated soils using Acinetobacter sp.  

SciTech Connect

Soils contaminated with polynuclear aromatic hydrocarbons (PAHs) pose a hazard to life. The remediation of such sites has been attempted using various methods such as solvent washing, air stripping, incineration, composting, electrokinetic remediation, and supercritical extraction. However, applicability of these physical, chemical, and biological treatment methods or their combination is critically dependent on soil characteristics, nature and level of contamination, site specifications, and economic feasibility, to name a few. Present research is aimed at studying the applicability of biological treatment for decontamination of industrial soil containing PAHs. The current preliminary study included soil analysis, contaminant characterization, and soil treatment using Acinetobacter sp. The soil treatment over a 5-week period, with minimal supplemental nutrient addition, showed removal efficiencies of 80% and more. The effect of initial microbial population in soil on the removal efficiency over a 5-week treatment period was studied. Experiments were designed to compare the removal efficiencies occurring in packed beds versus continuously-stirred tank reactor (CSTR)-type fermentation conditions. This also estimated a conservative range of decontamination efficiencies achievable using minimal control.

Joshi, M.M.; Lee, S. [Univ. of Akron, OH (United States)

1996-03-01

213

Biology of soil-transmitted helminths: the massive infection.  

PubMed

Soil-transmitted helminth infections when light-to-moderate usually are well tolerated, but heavy-to massive infections invariably cause disease. A massive infection with Ascaris lumbricoides may cause intestinal obstruction, liver abscess, or some other condition requiring surgical treatment; more regularly, however, ascaris disease is a form of malnutrition. Trichuris trichiura causes diarrhea and dysentery and, at times, rectal prolapse. The hookworms, Necator americanus and Ancylostoma duodenale, cause blood-loss from the intestine resulting in anemia. Necator infection is acquired percutaneously, and is more frequently massive than is that of Ancylostoma which may be acquired percutaneously or orally. Estimates of egg output in the feces, based on egg-counts by dilution, direct smear, or thick-film techniques, provide a reliable index of light, medium, or heavy infection. Acquisition of heavy infection with Ascaris and Trichuris depends on favorable qualities of the soil, and on the sorting action of rain which transports and concentrates the eggs of helminths in locations where survival and transmission are favored. The high frequency of heavy hookworm infection in southeastern United States and probably elsewhere may depend largely on the presence of feces-burying dung beetles. Human infection with soil-transmitted helminths of dogs and cats has become a serious public health problem attributable to the persistence of rural mores in the urban setting. PMID:1052507

Beaver, P C

1975-04-01

214

DYNAMICS OF SOIL FLORA AND FAUNA IN BIOLOGICAL CONTROL OF SOIL INHABITING PLANT PATHOGENS  

Technology Transfer Automated Retrieval System (TEKTRAN)

The cropland soil, which is comprised of spermosphere, rhizosphere and bulk soil, is populated by a wide array of microbial inhabitants. These microbial inhabitants include the microflora, represented by bacteria, actinomyces, archaea, fungi and algae and the micro- and mesofauna, such as protozoa, ...

215

Active manipulation of native soil microbial community structure and function to suppress soilborne diseases  

Technology Transfer Automated Retrieval System (TEKTRAN)

The reality of naturally occurring biologically-induced disease suppressive soils suggests opportunity for managing resident soil microbial communities as a disease control method. Disease suppressive soils have yielded a significant body of knowledge concerning operative mechanisms leading to t...

216

Microbial biomass, activity, and community structure in subsurface soils  

Microsoft Academic Search

Microbial biomass, community structure and activity were determined in the subsurface horizons of four contrasting soil types common to Alabama. Biomass and community structure were determined by analyzing the fatty acids of the extractable phospholipids. Activity was estimated by measuring the rate of enzymatic hydrolysis of fluorescein diacetate (FDA). In all four soils, biomass and activity declined with increasing depth;

Thomas W. Federle; Durell C. Dobbins; Janice R. Thornton-Manning; Daniel D. Jones

1986-01-01

217

Soil and Litter Animals.  

ERIC Educational Resources Information Center

|A lesson plan for soil study utilizes the Tullgren extraction method to illustrate biological concepts. It includes background information, equipment, collection techniques, activities, and references for identification guides about soil fauna. (MCO)|

Lippert, George

1991-01-01

218

Geophysical Monitoring of Microbial Activity within a Wetland Soil  

NASA Astrophysics Data System (ADS)

We performed Induced Polarization (IP) and Self Potential (SP) measurements to record the geoelectrical signatures of microbial activity within a wetland soil. The experiment was conducted in laboratory, utilizing an open flow column set up. Soil samples from Kearny Marsh (KM), a shallow water wetland, were collected and stored at 4o Celsius prior to the start of the experiment. Two columns were dry packed with a mix of KM soil and sterile Ottawa sand (50% by weight). One column was sterilized and used as a control while the other column retained the biologically active soil sample. Both columns were saturated with a minimal salts medium capable of supporting microbial life; after saturation, a steady flow rate of one pore volume per day was maintained throughout the experiment. Ambient temperature and pressure changes (at the inflow and outflow of each column) were continuously monitored throughout the experiment. Common geochemical parameters, such as Eh, pH, and fluid conductivity were measured at the inflow and outflow of each column at regular intervals. IP and SP responses were continuously recorded on both columns utilizing a series of electrodes along the column length; additionally for the SP measurements we used a reference electrode at the inflow tube. Strong SP anomalies were observed for all the locations along the active column. Black visible mineral precipitant also formed in the active column. The observed precipitation coincided with the times that SP anomalies developed at each electrode position. These responses are associated with microbial induced sulfide mineralization. We interpret the SP signal as the result of redox processes associated with this mineralization driven by gradients in ionic concentration and mobility within the column, similar to a galvanic cell mechanism. IP measurements show no correlation with these visual and SP responses. Destructive analysis of the samples followed the termination of the experiment. Scanning electron microscopy (SEM) and Energy Dispersive Spectrometry (EDS) were used to identify and quantify the presence and composition of the mineral precipitation in the control and active columns. Further geochemical measurements are currently being performed in order to confirm and more accurately quantify the mineralization and associated processes.

O'Brien, M.; Zhang, C.; Ntarlagiannis, D.; Slater, L.; Yee, N.

2007-05-01

219

Evaluation of the co-application of fly ash and sewage sludge on soil biological and biochemical quality.  

PubMed

Disposal of sewage sludge (SS) and fly ash (FA) is a multifaceted problem, which can affect environmental quality. FA has the potential to stabilize SS by reducing metal availability and making the SS suitable for application in the agricultural sector. An experiment was performed to evaluate soil biological quality changes with the combined amendment of SS and FA (fluidized bed combustion ash (FBCA) and lignite fly ash (LFA)). SS was amended with 0, 10, 30, 50 and 100%, (w/w) of FA, and then the FA-SS mixtures were incubated with red soil at 1:1 (v/v). Soil quality parameters such as pH, electrical conductivity, N, soil enzyme activities such as dehydrogenase (DHA), urease (URE), and catalase (CAT), and microbial biomass carbon (MBC) were evaluated at 20, 30, and 60 days of incubation, pH and EC increased with FA-SS dose; however, N decreased. DHA and URE were found to be increased with 10% LFA amendment; thereafter it decreased. However, URE increased up to 30% of FBCA. CAT and MBC increased with both FA amendments, even up to addition of 50% FA. Bioavailable Zn, Cu, and Co contents were decreased by the addition of FA. Principal component analysis showed that pH is the most influential factor. MBC appears to be a sensitive soil indicator for the effects that result from the addition of FA-SS. Phytotoxicity studies with Zea mays showed optimum performance at 30% FA. Addition of 10-30% FBCA or LFA to SS has a positive advantage on soil biological quality. PMID:22720414

Masto, Reginald E; Sunar, Kapil K; Sengupta, Taniya; Ram, Lal C; Rout, T K; Selvi, Vetrivel A; George, Joshy; Sinha, Awadhesh K

220

Influence of soil physicochemical and biological properties on the degradation and adsorption of the nematicide fosthiazate.  

PubMed

The degradation and adsorption of the organophosphorus nematicide fosthiazate were investigated in nine soils with various physicochemical and biological characteristics. Fosthiazate was more persistent in acidic soils (pH <6), with half-life (t1/2) values ranging from 53.3 to 57.7 days, compared to soils with higher pH (pH >7), with t1/2 ranging from 14.1 to 20.7 days. Application of antibacterial and antifungal antibiotics to soil samples resulted in a significant inhibition of fosthiazate degradation only in two of the three acidic soils. In contrast, soil autoclaving resulted in doubling the t1/2 of fosthiazate in all studied soils, suggesting that both microbial and abiotic processes contribute to fosthiazate degradation. Statistical analysis indicated a significant negative correlation (P < 0.01) between soil pH and t1/2. Fosthiazate was generally weakly adsorbed with Freundlich adsorption coefficient (Kf) values ranging from 1.23 to 2.74 mL/g. Fosthiazate concentration was strongly correlated with soil organic matter content with higher Kf values in soils with higher organic matter content (P < 0.01). The mean t1/2 and Kf values derived from the laboratory studies were used to parametrize the FOCUS groundwater (GW) models PRZM, PELMO, PEARL, and MACRO for nematicide application in potato and tomato crops. Predicted environmental concentrations produced by the models PEARL and MACRO suggested a potential risk for GW in several scenarios, unlike PELMO and PRZM, which predicted low risk for GW. These findings suggest that the environmental fate of fosthiazate is strongly influenced by soil characteristics and that this nematicide should be used with care in acidic, light soils with low organic matter content. PMID:16939340

Pantelelis, Ioannis; Karpouzas, Dimitrios G; Menkissoglu-Spiroudi, Urania; Tsiropoulos, Nikolas

2006-09-01

221

Biological activity of a leached chernozem contaminated with the products of combustion of petroleum gas and its restoration upon phytoremediation  

NASA Astrophysics Data System (ADS)

It is shown that contamination of leached chernozems by combustion products of petroleum gas favors changes in the biological activity of the soil: the number of hydrocarbon-oxidizing bacteria and micromycetes has increased, as well as the activity of catalase and lipase and phytotoxicity. Bromopsis inermis Leys used as a phytoameliorant has accelerated the destruction of hydrocarbons in the rhizosphere. The benzpyrene concentration in plants on contaminated soils considerably exceeds its background concentration.

Kireeva, N. A.; Novoselova, E. I.; Shamaeva, A. A.; Grigoriadi, A. S.

2009-04-01

222

Sulfation and biological activities of konjac glucomannan.  

PubMed

The sulfation of konjac glucomannan and its anti-HIV and blood anticoagulant activities were investigated. Konjac glucomannan is a polysaccharide occurring naturally in konjac plant tubers and has high molecular weights. Solubility in water is very low, and the aqueous solutions at low concentrations have high viscosity. Before sulfation, hydrolysis by diluted sulfuric acid was carried out to decrease the molecular weights of M¯n=19.2 × 10(4)-0.2 × 10(4). Sulfation with piperidine-N-sulfonic acid or SO3-pyridine complex gave sulfated konjac glucomannans with molecular weights of M¯n=1.0 × 10(4)-0.4 × 10(4) and degrees of sulfation (DS) of 1.3-1.4. It was found that the sulfated konjac glucomannans had potent anti-HIV activity at a 50% effective concentration, (EC50) of 1.2-1.3 ?g/ml, which was almost as high as that of an AIDS drug, ddC, whose EC50=3.2 ?g/ml, and moderate blood anticoagulant activity, AA=0.8-22.7 units/mg, compared to those of standard sulfated polysaccharides, curdlan (10 units/mg) and dextran (22.7 units/mg) sulfates. Structural analysis of sulfated konjac glucomannans with negatively charged sulfated groups was performed by high resolution NMR, and the interaction between poly-l-lysine with positively charged amino groups as a model compound of proteins and peptides was measured by surface plasmon resonance measurement, suggesting that the sulfated konjac glucomannans had a high binding stability on immobilized poly-l-lysine. The binding of sulfated konjac glucomannan was concentration-dependent, and the biological activity of the sulfated konjac glucomannans may be due to electrostatic interaction between the sulfate and amino groups. PMID:23544648

Bo, Surina; Muschin, Tegshi; Kanamoto, Taisei; Nakashima, Hideki; Yoshida, Takashi

2013-01-25

223

Influence of metal oxide particles on soil enzyme activity and bioaccumulation of two plants.  

PubMed

Particle size and metal species are important to both soil microbial toxicity and phytotoxicity in the soil ecosystem. The effects of CuO and ZnO nanoparticles (NPs) and microparticles (MPs) on soil microbial toxicity, phytotoxicity, and bioaccumulation in two crops (Cucumis sativus and Zea mays) were estimated in a soil microcosm. In the microcosm system, soil was artificially contaminated with 1,000 mg/kg CuO and ZnO NPs and MPs. After 15 days, we compared the microbial toxicity and phytotoxicity by particle size. In addition, C. sativus and Z. mays were cultivated in soils treated with CuO NPs and ZnO NPs, after which the treatment effects on bioaccumulation were evaluated. NPs were more toxic than MPs to microbes and plants in the soil ecosystem. We found that the soil enzyme activity and plant biomass were inhibited to the greatest extent by CuO NPs. However, in a Biolog test, substrate utilization patterns were more dependent upon metal type than particle size. Another finding indicated that the metal NP uptake amounts of plants depend on the plant species. In the comparison between C. sativus and Z. mays, the accumulation of Cu and Zn by C. sativus was noticeably higher. These findings show that metal oxide NPs may negatively impact soil bacteria and plants. In addition, the accumulation patterns of NPs depend on the plant species. PMID:23751560

Kim, Sunghyun; Sin, Hyunjoo; Lee, Sooyeon; Lee, Insook

2013-09-28

224

Effects of dormant- vs. growing-season fire in shortgrass steppe: Biological soil crust and perennial grass responses  

Microsoft Academic Search

This research experimentally examined seasonal effects of fire on biological soil crusts and perennial grasses in shortgrass steppe. We predicted dormant-season fire would have greater negative effects on biological soil crusts than fire during the growing season, but less of an impact on perennial grasses than fire during the growing season. Treatments were dormant- and growing-season fires and unburned reference

P. L. Ford; G. V. Johnson

2006-01-01

225

Conservation tillage, optimal water and organic nutrient supply enhance soil microbial activities during wheat (Triticum Aestivum L.) cultivation  

PubMed Central

The field experiments were conducted on sandy loam soil at New Delhi, during 2007 and 2008 to investigate the effect of conservation tillage, irrigation regimes (sub-optimal, optimal and supra-optimal water regimes), and integrated nutrient management (INM) practices on soil biological parameters in wheat cultivation. The conservation tillage soils has shown significant (p<0.05) increase in soil respiration (81.1%), soil microbial biomass carbon (SMBC) (104%) and soil dehydrogenase (DH) (59.2%) compared to the conventional tillage soil. Optimum water supply (3-irrigations) enhanced soil respiration over sub-optimum and supra-optimum irrigations by 13.32% and 79% respectively. Soil dehydrogenase (DH) activity in optimum water regime has also increased by 23.33% and 8.18% respectively over the other two irrigation regimes. Similarly, SMBC has also increased by 12.14% and 27.17% respectively in soil with optimum water supply compared to that of sub-optimum and supra-optimum water regime fields. The maximum increase in soil microbial activities is found when sole organic source (50% Farm Yard Manure+25% biofertilizer+25% Green Manure) has been used in combination with the conservation tillage and the optimum water supply. Study demonstrated that microbial activity could be regulated by tillage, water and nitrogen management in the soil in a sustainable manner.

Sharma, Pankaj; Singh, Geeta; Singh, Rana P.

2011-01-01

226

Conservation tillage, optimal water and organic nutrient supply enhance soil microbial activities during wheat (Triticum Aestivum L.) cultivation.  

PubMed

The field experiments were conducted on sandy loam soil at New Delhi, during 2007 and 2008 to investigate the effect of conservation tillage, irrigation regimes (sub-optimal, optimal and supra-optimal water regimes), and integrated nutrient management (INM) practices on soil biological parameters in wheat cultivation. The conservation tillage soils has shown significant (p<0.05) increase in soil respiration (81.1%), soil microbial biomass carbon (SMBC) (104%) and soil dehydrogenase (DH) (59.2%) compared to the conventional tillage soil. Optimum water supply (3-irrigations) enhanced soil respiration over sub-optimum and supra-optimum irrigations by 13.32% and 79% respectively. Soil dehydrogenase (DH) activity in optimum water regime has also increased by 23.33% and 8.18% respectively over the other two irrigation regimes. Similarly, SMBC has also increased by 12.14% and 27.17% respectively in soil with optimum water supply compared to that of sub-optimum and supra-optimum water regime fields. The maximum increase in soil microbial activities is found when sole organic source (50% Farm Yard Manure+25% biofertilizer+25% Green Manure) has been used in combination with the conservation tillage and the optimum water supply. Study demonstrated that microbial activity could be regulated by tillage, water and nitrogen management in the soil in a sustainable manner. PMID:24031665

Sharma, Pankaj; Singh, Geeta; Singh, Rana P

2011-06-01

227

Biological Degradation of Black Carbon in Temperate Forest Soils: Effects of Clay Mineralogy and Nitrogen Availability  

NASA Astrophysics Data System (ADS)

A critical knowledge gap in soil organic carbon (SOC) cycling concerns the SOC portion collectively known as pyrogenic C or black carbon (BC), which is a chemically heterogeneous class of highly reduced compounds produced by incomplete combustion. While the stocks of BC are significant in surface soils worldwide, this SOC pool has been considered to be relatively inert with negligible biologically mediated degradation of BC occurring. We will present findings from a laboratory incubation of dual-labeled (13C/15N) BC and its precursor wood (Pinus ponderosa) in two temperate soils (Haploxeralfs) that differ in their clay mineralogy (granitic versus andesitic parent material) and organic C content. In addition, we used N additions in the granitic soil to investigate the effects of N availability on soil and substrate C and N cycling. Sterile controls were used to demonstrate that the BC turnover observed was biotic. The laboratory incubations were carried out at 25°C and at 55% of soil water holding capacity. We are measuring the flux of mineralized 13C in respired CO2, dissolved organic C, soil microbial biomass, specific microbial groups (13C-phospholipid fatty acids) and density-defined soil organic matter fractions. The overall flux of 15N is being observed in the microbial biomass, soluble organic and inorganic pools, and organic matter fractions. We will present rates of biologically-mediated decomposition of BC and its precursor wood, as well as the effects of soil mineralogy and N availability on these rates and on products of decomposition. We will also present decomposition rates of native SOM in incubations with and without substrate to investigate C priming.

Bird, J. A.; Santos, F.; Torn, M. S.

2008-12-01

228

Radon flux density and radon soil volume activity seasonal variations associated with the soils freezing  

NASA Astrophysics Data System (ADS)

Measurements of radon soil volume activity and radon flux density from the soil surface is carried out while monitoring the stress-strain state of geological environment in order to forecast earthquakes as well as for ecological studies. It is known that these quantities may have significant seasonal fluctuations associated with the soil surface layer freezing. This process complicates the interpretation of experimental data. A mathematical model of radon transport in freezing soil surface layer is described in this paper. It is assumed that the frozen layer of soil is permeable to radon, but it has a lower diffusion coefficient. The thickness of the frozen layer increases with time and reaches a maximum value as the blanket of snow is fixed. The volume activity increase factor at a depth of 0.7 m and surface radon flux decrease factor during soil freezing are calculated. The calculation was performed for the values of the maximum depth of soil freezing from 0 to 1 m and for the values of the soil radon diffusion length from 0.5 to 2 m. The calculation revealed that the freezing of the upper layer of soil radon volume activity at a depth of 0.7 m on average increases in 1.7 times, and the flux density of radon from the soil surface decreases by an average of 1.8 times. The results of the 3-month of the radon soil volume activity at depths of 0.7 and 2.7 m and ground temperature at depths of 0.01, 0.21, 0.31, 0.51, 1, 2, 3 m monitoring at a research testing area Yekaterinburg is obtained. The theoretical results are well agreed with experimental data. The results obtained in this paper can be used when interpreting the values of volume activity of radon in soil air and the flux density of radon from the soil surface, measured in the cold season.

Klimshin, A.

2011-12-01

229

Soil phosphorus dynamics in cropping systems managed according to conventional and biological agricultural methods  

Microsoft Academic Search

The effects of conventional and biological farming systems on soil P dynamics were studied by measuring some microbiological parameters after 13 years of different cropping systems. The treatments included control, biodynamic, bio-organic, and conventional plots and a mineral fertilizer treatment. The farming systems differed mainly in the form and quantity of nutrients applied and in the plant protection strategies. The

A. Oberson; J. C. Fardeau; J. M. Besson; H. Sticher

1993-01-01

230

Inferring biological soil crust successional stage using combined PLFA, DGGE, physical and biophysiological analyses  

Microsoft Academic Search

Arid areas are highly sensitive to climate change and are ideal model systems to study the potential impact of climate change on species' community structure. Biological soil crust (BSC) formation plays an ecological role in a number of key processes in the development of dry ecosystems. It was hypothesized that BSC succession and function are affected by aridity level and

Eli Zaady; Eric A. Ben-David; Yoni Sher; Regina Tzirkin; Ali Nejidat

2010-01-01

231

Selection of biological control agents for controlling soil and seed-borne diseases in the field  

Microsoft Academic Search

Different screening methods for selection of biological control agents (BCAs), for controlling soil and seed-borne diseases, are discussed. The shortcomings of laboratory methods focused on mechanism of action are discussed and we conclude that these methods should be used with caution if candidates with multifactorial or plant mediated mechanisms of control are to be obtained. In vitro screens may be

I. M. B. Knudsen; J. Hockenhull; D. Funck Jensen; B. Gerhardson; M. Hökeberg; R. Tahvonen; E. Teperi; L. Sundheim; B. Henriksen

1997-01-01

232

Crushed Cotton Gin Compost Effects on Soil Biological Properties, Nutrient Leaching Losses, and Maize Yield  

Microsoft Academic Search

There is currently interest in the use of industrial by-products to reduce the use of synthetic fertilizers; however, most organic wastes contain relatively low N levels. Our objectives were to: (i) determine the effect of incorporating crushed cotton gin compost, with and without inorganic fertilizers, on soil biological properties during three maize crops (Zea mays L., cv. Tundra); (ii) study

M. Tejada; J. L. Gonzalez

2006-01-01

233

Modeling the variability in annual carbon fluxes related to biological soil crusts in a Mediterranean shrubland  

Microsoft Academic Search

Biological soil crusts (BSC) constitute a spatially prominent part of the photosynthesizing vegetation in many dryland ecosystems. This study assesses the annual net carbon deposition related to BSC growth in a Mediterranean shrubland for the years 2001-2003 using a model developed to account for the nature of hydration in the poikilohydric life trait of the BSC. Data for BSC-related net

B. Wilske; J. Burgheimer; K. Maseyk; A. Karnieli; E. Zaady; M. O. Andreae; D. Yakir; J. Kesselmeier

2009-01-01

234

Watering, Fertilization, and Slurry Inoculation Promote Recovery of Biological Crust Function in Degraded Soils  

Microsoft Academic Search

Biological soil crusts are very sensitive to human-induced disturbances and are in a degraded state in many areas throughout their range. Given their importance in the functioning of arid and semiarid ecosystems, restoring these crusts may contribute to the recovery of ecosystem functionality in degraded areas. We conducted a factorial microcosm experiment to evaluate the effects of inoculation type (discrete

Fernando T. Maestre; Noelia Martín; Beatriz Díez; Rosario López-Poma; Fernando Santos; Ignacio Luque; Jordi Cortina

2006-01-01

235

Biological Soil Crusts of Sand Dunes in Cape Cod National Seashore, Massachusetts, USA  

Microsoft Academic Search

Biological soil crusts cover hundreds of hectares of sand dunes at the northern tip of Cape Cod National Seashore (Massachusetts, USA). Although the presence of crusts in this habitat has long been recognized, neither the organisms nor their ecological roles have been described. In this study, we report on the microbial community composition of crusts from this region and describe

S. M. Smith; R. M. M. Abed; F. Gercia-Pichel

2004-01-01

236

HYDROGEN PEROXIDE DECAY IN WATERS WITH SUSPENDED SOILS: EVIDENCE FOR BIOLOGICALLY MEDIATED PROCESSES  

EPA Science Inventory

Hydrogen peroxide decay studies have been conducted in suspensions of several well-characterized soils and in natural water samples. inetic and product studies indicated that the decay was biologically mediated and could be described by psuedo first-order rate expressions. t an i...

237

Agro-ecological strategies in north lampung, indonesia: social constraints to biological management of soil fertility  

Microsoft Academic Search

The article examines the socio-cultural and political factors which affect the adoption of biological management of soil fertility in Javanese and Lampungese farming communities of the Province of Lampung, Indonesia. The research was carried out using a hybrid methodological framework, thus blending quantitative and qualitative analysis to provide a holistic picture of the agro-environmental and social conditions of the area.

R. Gauthier

2000-01-01

238

EFFECT OF FIRE AND GRAZING ON VEGETATION AND BIOLOGICAL SOIL CRUSTS IN EASTERN MONTANA  

Technology Transfer Automated Retrieval System (TEKTRAN)

Little information exists about fire and grazing effects on biological soil crusts in the northern Great Plains. Four permanent quadrats (20 x 50 cm) were selected based on presence of lichens and mosses to measure canopy cover in each of 4 blocks and 3 treatments in a randomized block design. Tre...

239

Role of Biological Soil Crusts on hydrological cycle drivers of semiarid ecosystems  

NASA Astrophysics Data System (ADS)

In arid and semiarid ecosystems, where plant cover is scarce, other surface components like soil crusts or stones acquire a very relevant role on local hydrologic regimes, controlling infiltration rates and they also affect erosion. The interplant spaces of these ecosystems are very often covered by biological soil crusts (BSCs), which are a community of microorganisms, including cyanobacteria, algae, fungi, lichens and mosses living in the soil surface. These BSCs regulate the horizontal and vertical fluxes of water, carbon, and nutrients into and from the soil and play crucial hydrological, geomorphological and ecological roles in these ecosystems. We analyse the role of BSCs on the different components of the water balance (infiltration-runoff, evaporation and soil moisture) in two representative semiarid ecosystems of SE Spain. The influence of BSCs on runoff-infiltration and erosion has been studied by rainfall simulations and with field plots under natural rainfall at different spatial scales, on BSCs in different stages of their development. Results show higher infiltration in BSCs than in physical crusts and different responses among BSCs depending on soil and rainfall properties and the considered spatial scale but, as a general trend, the greater the development of the BSCs, the greater the infiltration rate and the lower the sediment yield. In addition, given that BSCs modify many soil surface properties, such as surface stability, cohesiveness, cracking, porosity or micro-topography, which also affect runoff and erosion processes, we have examined the relative importance of BSCs features (cover, composition, roughness, water repellency, etc) on runoff and erosion and their direct and indirect relationships and how they interact with rainfall characteristics. By using microlysimeters, similar evaporative losses were measured among crust types in late spring when ambient conditions were quite warm and all crust types lost water very quickly. However, monitoring of soil moisture during a whole year shows differences in soil moisture content and soil water loss between the types of BSCs depending on the moment of the year. Thus, during wet periods higher soil moisture and slower soil water losses were recorded in lichen-covered than in cyanobacteria-covered soils. While during dry periods, faster soil water depletion and lower soil moisture occurred under lichen than in soils covered by cyanobacterial BSCs. In conclusion, our results show the important roles of BSCs modulating the water cycle in semiarid ecosystems.

Canton, Y.; Chamizo, S.; Rodriguez-Caballero, E.; Miralles, I.; Lazaro, R.; Sole-Benet, A.; Domingo, F.

2012-04-01

240

The variation of morphological features and mineralogical components of biological soil crusts in the Gurbantunggut Desert of Northwestern China  

Microsoft Academic Search

Increasingly complex life forms were found in older biological soil crusts in the Gurbantaunggut Desert in Northwestern China.\\u000a These crusts may play a critical role in mineral erosion and desert soil formation by modifying the weathering environment\\u000a and ultimately affecting mineralogical variance. To test this hypothesis, variations in the morphological features and mineralogical\\u000a components of successional biological soil crusts at

Rongyi Chen; Yuanming Zhang; Yuan Li; Wenshou Wei; Jing Zhang; Nan Wu

2009-01-01

241

Stoichiometry of soil enzyme activity at global scale.  

PubMed

Extracellular enzymes are the proximate agents of organic matter decomposition and measures of these activities can be used as indicators of microbial nutrient demand. We conducted a global-scale meta-analysis of the seven-most widely measured soil enzyme activities, using data from 40 ecosystems. The activities of beta-1,4-glucosidase, cellobiohydrolase, beta-1,4-N-acetylglucosaminidase and phosphatase g(-1) soil increased with organic matter concentration; leucine aminopeptidase, phenol oxidase and peroxidase activities showed no relationship. All activities were significantly related to soil pH. Specific activities, i.e. activity g(-1) soil organic matter, also varied in relation to soil pH for all enzymes. Relationships with mean annual temperature (MAT) and precipitation (MAP) were generally weak. For hydrolases, ratios of specific C, N and P acquisition activities converged on 1 : 1 : 1 but across ecosystems, the ratio of C : P acquisition was inversely related to MAP and MAT while the ratio of C : N acquisition increased with MAP. Oxidative activities were more variable than hydrolytic activities and increased with soil pH. Our analyses indicate that the enzymatic potential for hydrolyzing the labile components of soil organic matter is tied to substrate availability, soil pH and the stoichiometry of microbial nutrient demand. The enzymatic potential for oxidizing the recalcitrant fractions of soil organic material, which is a proximate control on soil organic matter accumulation, is most strongly related to soil pH. These trends provide insight into the biogeochemical processes that create global patterns in ecological stoichiometry and organic matter storage. PMID:18823393

Sinsabaugh, Robert L; Lauber, Christian L; Weintraub, Michael N; Ahmed, Bony; Allison, Steven D; Crenshaw, Chelsea; Contosta, Alexandra R; Cusack, Daniela; Frey, Serita; Gallo, Marcy E; Gartner, Tracy B; Hobbie, Sarah E; Holland, Keri; Keeler, Bonnie L; Powers, Jennifer S; Stursova, Martina; Takacs-Vesbach, Cristina; Waldrop, Mark P; Wallenstein, Matthew D; Zak, Donald R; Zeglin, Lydia H

2008-09-25

242

Brain activity evoked by inverted and imagined biological motion  

Microsoft Academic Search

Previous imaging research has identified an area on the human posterior superior temporal sulcus (STS) activated upon viewing biological motion. The current experiments explore the relationship between neural activity within this region and perceptual experience. Biological motion perception is orientation dependent: inverting point-light animations make them more difficult to see. We measured activity levels within this region as observers viewed

E. D. Grossman; R. Blake

2001-01-01

243

Mercury and arsenic pollution in soil and biological samples around the mining town of Obuasi, Ghana  

Microsoft Academic Search

Samples of soils, plantain (Musa paradisiaca), water fern (Ceratopteris cornuta), elephant grass (Pennisetum purpureum), cassava (Manihot esculenta) and mud fish (Heterobranchus bidorsalis) were collected from Obuasi and its environs, which is the most active gold mining town in Ghana. The distribution of mercury and arsenic in these samples from fourteen sampling sites was determined. The annual average surficial soil concentrations

E. H. Amonoo-Neizer; David Nyamah; S. B. Bakiamoh

1996-01-01

244

Monascus secondary metabolites: production and biological activity.  

PubMed

The genus Monascus, comprising nine species, can reproduce either vegetatively with filaments and conidia or sexually by the formation of ascospores. The most well-known species of genus Monascus, namely, M. purpureus, M. ruber and M. pilosus, are often used for rice fermentation to produce red yeast rice, a special product used either for food coloring or as a food supplement with positive effects on human health. The colored appearance (red, orange or yellow) of Monascus-fermented substrates is produced by a mixture of oligoketide pigments that are synthesized by a combination of polyketide and fatty acid synthases. The major pigments consist of pairs of yellow (ankaflavin and monascin), orange (rubropunctatin and monascorubrin) and red (rubropunctamine and monascorubramine) compounds; however, more than 20 other colored products have recently been isolated from fermented rice or culture media. In addition to pigments, a group of monacolin substances and the mycotoxin citrinin can be produced by Monascus. Various non-specific biological activities (antimicrobial, antitumor, immunomodulative and others) of these pigmented compounds are, at least partly, ascribed to their reaction with amino group-containing compounds, i.e. amino acids, proteins or nucleic acids. Monacolins, in the form of ?-hydroxy acids, inhibit hydroxymethylglutaryl-coenzyme A reductase, a key enzyme in cholesterol biosynthesis in animals and humans. PMID:23179468

Patakova, Petra

2012-11-20

245

BLENDING FOUNDRY SANDS WITH SOIL: EFFECT ON DEHYDROGENASE ACTIVITY  

Technology Transfer Automated Retrieval System (TEKTRAN)

Each year the foundry industry generates several million tons of waste foundry sands (WFSs) that are suitable for the production of manufactured soils; however, their impact upon soil microbial activity is largely untested. In this study we monitored the dehydrogenase activity (DHA) over a 12-week ...

246

Measurement of microbial biomass and activity in landfill soils.  

SciTech Connect

Two complementary techniques, which have been widely used to provide a general measure of microbial biomass or microbial activity in natural soils, were evaluated for their applicability to soils from the Mallard North and Mallard Lake Landfills, DuPage County, Illinois, U.S.A. Included were: (1) a potassium sulphate extraction technique with quantification of organic carbon for measurement of microbial biomass; and (2) an arginine ammonification technique for microbial activity. Four profiles consisting of replaced soils were sampled for this study; units included topsoil (mixed mollisol A and B horizons), compacted clay cover (local calcareous Wisconsinan age glacial till), and mixed soil/refuse samples. Internally consistent results across the four profiles and good correlations with other independent indicators of microbial activity (moisture, organic matter content, nitrogen, and phosphorus) suggest that, even though these techniques were developed mainly for natural mineral soils, they are also applicable to disturbed landfill soils.

Bogner, J. E.; Miller, R. M.; Spokas, K.; Environmental Research

1995-01-01

247

Effects of increasing periods under intensive arable vegetable production on biological, chemical and physical indices of soil quality  

Microsoft Academic Search

The effects on soil condition of increasing periods under intensive cultivation for vegetable production on a Typic Haplohumult\\u000a were compared with those of pastoral management using soil biological, physical and chemical indices of soil quality. The\\u000a majority of the soils studied had reasonably high pH, exchangeable cation and extractable P levels reflecting the high fertilizer\\u000a rates applied to dairy pasture

R. J. Haynes; R. Tregurtha

1999-01-01

248

Effects of CO[sub 2] and climate change on forest trees: Soil biology and enzymology  

SciTech Connect

Samples of Teracosm soils were analyzed shortly after initial setup to determine whether initial conditions were equivalent and matched expected values for local soils. Total and active fungal biomass, active bacterial biomass and protozoan numbers were reduced, with greatest decreases occurring in the A horizon. No effect was observed on total bacterial biomass, nematode or anthropod densities, but changes in nematode and arthropod species composition occurred. Significant differences in total density and species composition occurred between the enclosed Teracosms and the open controls. Arthropod and nematode community structure in the three altitudinal field sites had significantly diverged. No significant differences in activities of key soil enzymes in C- and N-cycling (acid phosphatase, protease, B-glucosidase, phenol oxidase and peroxidase) were found between initial samples relative to treatment, but all levels were significantly difference relative to depth in soil profile. Activities were within ranges previously observed in forests of the Pacific Northwest.

Moldenke, A.R.; Baumeister, N.; Caldwell, B.A.; Griffith, R.; Ingham, E.R.; Wernz, J. (Oregon State Univ., Corvallis, OR (United States)); Johnson, M.G.; Rygiewicz, P.T.; Tingey, D.T. (Environmental Protection Agency, Corvallis, OR (United States))

1994-06-01

249

Do biotic interactions modulate ecosystem functioning along stress gradients? Insights from semi-arid plant and biological soil crust communities  

PubMed Central

Climate change will exacerbate the degree of abiotic stress experienced by semi-arid ecosystems. While abiotic stress profoundly affects biotic interactions, their potential role as modulators of ecosystem responses to climate change is largely unknown. Using plants and biological soil crusts, we tested the relative importance of facilitative–competitive interactions and other community attributes (cover, species richness and species evenness) as drivers of ecosystem functioning along stress gradients in semi-arid Mediterranean ecosystems. Biotic interactions shifted from facilitation to competition along stress gradients driven by water availability and temperature. These changes were, however, dependent on the spatial scale and the community considered. We found little evidence to suggest that biotic interactions are a major direct influence upon indicators of ecosystem functioning (soil respiration, organic carbon, water-holding capacity, compaction and the activity of enzymes related to the carbon, nitrogen and phosphorus cycles) along stress gradients. However, attributes such as cover and species richness showed a direct effect on ecosystem functioning. Our results do not agree with predictions emphasizing that the importance of plant–plant interactions will be increased under climate change in dry environments, and indicate that reductions in the cover of plant and biological soil crust communities will negatively impact ecosystems under future climatic conditions.

Maestre, Fernando T.; Bowker, Matthew A.; Escolar, Cristina; Puche, Maria D.; Soliveres, Santiago; Maltez-Mouro, Sara; Garcia-Palacios, Pablo; Castillo-Monroy, Andrea P.; Martinez, Isabel; Escudero, Adrian

2010-01-01

250

Microbial Enzyme Activity and Carbon Cycling in Grassland Soil Fractions  

NASA Astrophysics Data System (ADS)

Extracellular enzymes are necessary to degrade complex organic compounds present in soils. Using physical fractionation procedures, we tested whether old soil carbon is spatially isolated from degradative enzymes across a prairie restoration chronosequence in Illinois, USA. We found that carbon-degrading enzymes were abundant in all soil fractions, including macroaggregates, microaggregates, and the clay fraction, which contains carbon with a mean residence time of ~200 years. The activities of two cellulose-degrading enzymes and a chitin-degrading enzyme were 2-10 times greater in organic matter fractions than in bulk soil, consistent with the rapid turnover of these fractions. Polyphenol oxidase activity was 3 times greater in the clay fraction than in the bulk soil, despite very slow carbon turnover in this fraction. Changes in enzyme activity across the restoration chronosequence were small once adjusted for increases in soil carbon concentration, although polyphenol oxidase activity per unit carbon declined by 50% in native prairie versus cultivated soil. These results are consistent with a `two-pool' model of enzyme and carbon turnover in grassland soils. In light organic matter fractions, enzyme production and carbon turnover both occur rapidly. However, in mineral-dominated fractions, both enzymes and their carbon substrates are immobilized on mineral surfaces, leading to slow turnover. Soil carbon accumulation in the clay fraction and across the prairie restoration chronosequence probably reflects increasing physical isolation of enzymes and substrates on the molecular scale, rather than the micron to millimeter scale.

Allison, S. D.; Jastrow, J. D.

2004-12-01

251

Biological Remediation of Soil: An Overview of Global Market and Available Technologies  

Microsoft Academic Search

\\u000a Due to a wide range of industrial and agricultural activities, a high number of chemical contaminants is released into the\\u000a environment, causing a significant concern regarding potential toxicity, carcinogenicity, and potential for bioaccumulation\\u000a in living systems of various chemicals in soil. Although microbial activity in soil accounts for most of the degradation of\\u000a organic contaminants, chemical and physical mechanisms can

Ajay Singh; Ramesh C. Kuhad; Owen P. Ward

252

Microbial Biomass and Activity in Lead-Contaminated Soil  

PubMed Central

Microbial community diversity, potential microbial activity, and metal resistance were determined in three soils whose lead contents ranged from 0.00039 to 48 mmol of Pb kg of soil?1. Biomass levels were directly related to lead content. A molecular analysis of 16S rRNAs suggested that each soil contained a complex, diverse microbial community. A statistical analysis of the phospholipid fatty acids indicated that the community in the soil having the highest lead content was not related to the communities in the other soils. All of the soils contained active microbial populations that mineralized [14C]glucose. In all samples, 10 to 15% of the total culturable bacteria were Pb resistant and had MIC of Pb for growth of 100 to 150 ?M.

Konopka, A.; Zakharova, T.; Bischoff, M.; Oliver, L.; Nakatsu, C.; Turco, R. F.

1999-01-01

253

Unexpected Stereochemical Tolerance for the Biological Activity of Tyroscherin  

PubMed Central

Here we describe the concise syntheses of the 15 diastereomers and key analogs of the natural product tyroscherin. While systematic analysis of the analogs clearly demonstrated that the hydrocarbon tail is important for biological activity, structure-activity relationship studies of the complete tyroscherin diastereoarray revealed a surprisingly expansive stereochemical tolerance for the cytotoxic activity. Our results represent a departure from the tenet that biological activity is constrained to a narrow pharmacophore, and highlight the recently emerging appreciation for stereochemical flexibility in defining the essential structural elements of biologically active small molecules.

Tae, Hyun Seop; Hines, John; Schneekloth, Ashley R.; Crews, Craig M.

2011-01-01

254

Biology Notes.  

ERIC Educational Resources Information Center

|Describes laboratory procedures, demonstrations, and classroom activities/materials, including chi-square tests on a microcomputer, an integrated biology game, microscope slides of leaf stomata, culturing soil nematodes, technique for watering locust egg-laying tubes, hazards of biological chemicals (such as benzene, benzidene, calchicine,…

School Science Review, 1983

1983-01-01

255

Soil enzyme activities and organic matter composition in a turfgrass chronosequence  

Microsoft Academic Search

Highly managed turfgrass systems accumulate considerable soil organic C, which supports a diverse and robust soil microbial community. Degradation of this soil organic C is mediated by a suite of soil enzymes. The relationship between these enzyme activities and the quality of soil organic C is central to understanding the dynamics of soil organic matter. We examined the activities of

Wei Shi; Emily Dell; Daniel Bowman; Kannan Iyyemperumal

2006-01-01

256

Active and passive organic matter fractions in Mediterranean forest soils  

Microsoft Academic Search

Soil organic carbon (C) is a complex set of pools, and to understand its dynamics it is necessary to know which of these pools\\u000a are active at a given moment, and which act as passive, due to either physical protection or biochemical recalcitrance, or\\u000a both. This matter has been studied mainly in agricultural soils. For forest soils, especially in Mediterranean

Pere Rovira; Montserrat Jorba; Joan Romanyà

2010-01-01

257

PHOSPHOLIPID AND FDA ACTIVITY MEASUREMENTS ADAPTED TO BIOLOGICAL GAC  

EPA Science Inventory

Established microbial ecology analytical techniques for measuring the quantity and activity of bacteria were examined for use on biological granular activated carbon (GAC). ctivity was determined using the fluorescein diacetate (FDA) assay. he assay was tested and accordingly cor...

258

Regenerable dialkylaminoalkyl cellulose support matrix for immobilizing biologically active materials  

SciTech Connect

This patent describes a method of immobilizing biologically active material on a support matrix and regenerating the support matrix from subsequently deactivated biologically active material. It comprises: coating a core support with a cellulose ester, removing by hydrolysis at least about 80% of the ester groups to provide free hydroxyl groups, converting the hydroxyl groups to dialkylaminoalkyl ether moieties, the dialkylaminoalkyl moiety having the formula R{sub {ital a}}R{sub {ital b}}N(CH{sub 2}){sub {ital p}{minus}}, where R{sub {ital a}}, R{sub {ital b}} are independently selected from the group consisting of alkyl groups of the formula C{sub {ital n}}H{sub 2{ital n}+1}, with n being an integer from 1 to about 20, and p being an integer from 2 to about 10, to afford a support matrix, contacting the support matrix with a solution of biologically active material having net negative charge under immobilizing conditions to absorb the biologically active material onto the support matrix by ion exchange forces to afford an active immobilized biological material system. It uses the active immobilized biological material system to catalyze a reaction whereby the immobilized biological material system becomes inactive, contacting the subsequently deactivated immobilized biological material system with an aqueous solution of a abase or highly dissociated salt at a concentration, a temperature, and for a time sufficient to remove the deactivated biological material immobilized thereon, removing excess base or salt by washing with water or a buffer solution contacting the washed support matrix with a solution of the biologically active material to produce a regenerated support matrix containing the biologically active material, and recovering the regenerated support matrix.

Lapins, C.D.; Tsuda, Y.

1990-06-12

259

Dynamic cyanobacterial response to hydration and dehydration in a desert biological soil crust  

PubMed Central

Biological soil crusts (BSCs) cover extensive portions of the earth's deserts. In order to survive desiccation cycles and utilize short periods of activity during infrequent precipitation, crust microorganisms must rely on the unique capabilities of vegetative cells to enter a dormant state and be poised for rapid resuscitation upon wetting. To elucidate the key events involved in the exit from dormancy, we performed a wetting experiment of a BSC and followed the response of the dominant cyanobacterium, Microcoleus vaginatus, in situ using a whole-genome transcriptional time course that included two diel cycles. Immediate, but transient, induction of DNA repair and regulatory genes signaled the hydration event. Recovery of photosynthesis occurred within 1?h, accompanied by upregulation of anabolic pathways. Onset of desiccation was characterized by the induction of genes for oxidative and photo-oxidative stress responses, osmotic stress response and the synthesis of C and N storage polymers. Early expression of genes for the production of exopolysaccharides, additional storage molecules and genes for membrane unsaturation occurred before drying and hints at preparedness for desiccation. We also observed signatures of preparation for future precipitation, notably the expression of genes for anaplerotic reactions in drying crusts, and the stable maintenance of mRNA through dormancy. These data shed light on possible synchronization between this cyanobacterium and its environment, and provides key mechanistic insights into its metabolism in situ that may be used to predict its response to climate, and or, land-use driven perturbations.

Rajeev, Lara; da Rocha, Ulisses Nunes; Klitgord, Niels; Luning, Eric G; Fortney, Julian; Axen, Seth D; Shih, Patrick M; Bouskill, Nicholas J; Bowen, Benjamin P; Kerfeld, Cheryl A; Garcia-Pichel, Ferran; Brodie, Eoin L; Northen, Trent R; Mukhopadhyay, Aindrila

2013-01-01

260

Dynamic cyanobacterial response to hydration and dehydration in a desert biological soil crust.  

PubMed

Biological soil crusts (BSCs) cover extensive portions of the earth's deserts. In order to survive desiccation cycles and utilize short periods of activity during infrequent precipitation, crust microorganisms must rely on the unique capabilities of vegetative cells to enter a dormant state and be poised for rapid resuscitation upon wetting. To elucidate the key events involved in the exit from dormancy, we performed a wetting experiment of a BSC and followed the response of the dominant cyanobacterium, Microcoleus vaginatus, in situ using a whole-genome transcriptional time course that included two diel cycles. Immediate, but transient, induction of DNA repair and regulatory genes signaled the hydration event. Recovery of photosynthesis occurred within 1?h, accompanied by upregulation of anabolic pathways. Onset of desiccation was characterized by the induction of genes for oxidative and photo-oxidative stress responses, osmotic stress response and the synthesis of C and N storage polymers. Early expression of genes for the production of exopolysaccharides, additional storage molecules and genes for membrane unsaturation occurred before drying and hints at preparedness for desiccation. We also observed signatures of preparation for future precipitation, notably the expression of genes for anaplerotic reactions in drying crusts, and the stable maintenance of mRNA through dormancy. These data shed light on possible synchronization between this cyanobacterium and its environment, and provides key mechanistic insights into its metabolism in situ that may be used to predict its response to climate, and or, land-use driven perturbations. PMID:23739051

Rajeev, Lara; da Rocha, Ulisses Nunes; Klitgord, Niels; Luning, Eric G; Fortney, Julian; Axen, Seth D; Shih, Patrick M; Bouskill, Nicholas J; Bowen, Benjamin P; Kerfeld, Cheryl A; Garcia-Pichel, Ferran; Brodie, Eoin L; Northen, Trent R; Mukhopadhyay, Aindrila

2013-06-06

261

The ice nucleation activity of biological aerosols  

NASA Astrophysics Data System (ADS)

Primary Biological Aerosol Particles (PBAPs), including bacteria, spores and pollen may be important for several atmospheric processes. Particularly, the ice nucleation caused by PBAPs is a topic of growing interest, since their impact on ice cloud formation and thus on radiative forcing, an important parameter in global climate is not yet fully understood. In laboratory model studies we investigated the ice nucleation activity of selected PBAPs. We studied the immersion mode freezing using water-oil emulsion, which we observed by optical microscopy. We particularly focused on pollen. We show that pollen of different species strongly differ in their ice nucleation behavior. The average freezing temperatures in laboratory experiments range from 240 K to 255 K. As the most efficient nuclei (silver birch, Scots pine and common juniper pollen) have a distribution area up to the Northern timberline, their ice nucleation activity might be a cryoprotective mechanism. For comparison the ice nucleation activity of Snomax, fungal spores, and mushrooms will be discussed as well. In the past, pollen have been rejected as important atmospheric IN, as they are not as abundant in the atmosphere as bacteria or mineral dust and are too heavy to reach higher altitudes. However, in our experiments (Pummer et al. 2011) it turned out that water, which had been in contact with pollen and then been separated from the bodies, nucleates as good as the pollen grains themselves. So the ice nuclei have to be easily-suspendable macromolecules (100-300 kDa) located on the pollen. Once extracted, they can be distributed further through the atmosphere than the heavy pollen grains and so augment the impact of pollen on ice cloud formation even in the upper troposphere. It is widely known, that material from the pollen, like allergens and sugars, can indeed leave the pollen body and be distributed independently. The most probable mechanism is the pollen grain bursting by rain, which releases material, like allergens (Schäppi et al., 1999). As a consequence allergenic material was found in aerosol particles smaller than 5 µm, which contained no pollen or bigger fragments (Solomon et al., 1983). The release of material by bursting of wet pollen has been observed by electron microscopy (Swoboda et al., 2001). Not only allergens, but also sugars originating from pollen can be detected in the atmosphere (Yttri et al., 2007). These authors see pollen rupture and wood burning as their main sources in the atmosphere. The contrast between the hydrophilic properties of many of the surface components and the relative hydrophobia of the sporopollenin boosts the suspension of surface components in water droplets. According to that we conclude that the impact of pollen on the global atmosphere might have been underestimated. Additionally, our experiments lead to the conclusion that pollen ice nuclei, in contrast to bacterial and fungal ice nucleating proteins, are non-proteinaceous compounds.

Grothe, H.; Pummer, B.; Bauer, H.; Bernardi, J.

2012-04-01

262

Microbial Community Structure and Enzyme Activities in Semiarid Agricultural Soils  

Microsoft Academic Search

The effect of agricultural management practices on the microbial community structure and enzyme activities of semiarid soils of different textures in the Southern High Plains of Texas were investigated. The soils (sandy clay loam, fine sandy loam and loam) were under continuous cotton (Gossypium hirsutum L.) or in rotations with peanut (Arachis hypogaea L.), sorghum (Sorghum bicolor L.) or wheat

V. A. Acosta-Martinez; T. M. Zobeck; T. E. Gill; A. C. Kennedy

2002-01-01

263

Measurements of microbial community activities in individual soil macroaggregates  

Technology Transfer Automated Retrieval System (TEKTRAN)

The functional potential of single soil aggregates may provide insights into the localized distribution of microbial activities better than traditional assays conducted on bulk quantities of soil. Thus, we scaled down enzyme assays for ß-glucosidase, N-acetyl-ß-D-glucosaminidase, lipase, and leucine...

264

Blending foundry sands with soil: Effect on dehydrogenase activity  

Microsoft Academic Search

Each year U.S. foundries landfill several million tons of sand that can no longer be used to make metalcasting molds and cores. A possible use for these materials is as an ingredient in manufactured soils; however, potentially harmful metals and resin binders (used to make cores) may adversely impact the soil microbial community. In this study, the dehydrogenase activity (DHA)

Robert S. Dungan; Urzsula Kukier; Brad Lee

2006-01-01

265

The Soil Moisture Active/Passive Mission (SMAP)  

Technology Transfer Automated Retrieval System (TEKTRAN)

The Soil Moisture Active/Passive (SMAP) mission will deliver global views of soil moisture content and its freeze/thaw state that are critical terrestrial water cycle state variables. Polarized measurements obtained with a shared antenna L-band radar and radiometer system will allow accurate estima...

266

Studying the Activities of Microorganisms in Soil Using Slides.  

ERIC Educational Resources Information Center

|Two implanted slide techniques are described by which activity of proteolylic bacteria and the growth of algae in the soil can be readily studied by school students using simple apparatus and methods. Variations are suggested for studying the effects of agricultural practices and environmental conditions on the soil bacteria and algae.…

Cullimore, D. Roy; Pipe, Annette E.

1980-01-01

267

Impact of sugar industry effluents on soil cellulase activity  

Microsoft Academic Search

An assessment on the impact of sugar industry wastes on soil physicochemical and cellulase activity in waste dump sites, carried out in urban Nandyal, Southern India. Some core samples were collected from the selected profile pits at different soil horizons of dump (test) and non-dump sites (control). The experimental results indicated that, most of the physicochemical properties such as silt,

M. Nagaraju; G. Narasimha; V. Rangaswamy

2009-01-01

268

ACID RAIN AND SOIL MICROBIAL ACTIVITY: EFFECTS AND THEIR MECHANISMS  

EPA Science Inventory

In the investigation, our aim was to determine if acid rain affects soil microbial activity and to identify possible mechanisms of observed effects. A Sierran forest soil (pH 6.4) planted with Ponderosa pine seedlings was exposed to simulated rain (pH 2.0, 3.0, 4.0 and 5.6) with ...

269

Soil Properties, Nutrient Dynamics, and Soil Enzyme Activities Associated with Garlic Stalk Decomposition under Various Conditions  

PubMed Central

The garlic stalk is a byproduct of garlic production and normally abandoned or burned, both of which cause environmental pollution. It is therefore appropriate to determine the conditions of efficient decomposition, and equally appropriate to determine the impact of this decomposition on soil properties. In this study, the soil properties, enzyme activities and nutrient dynamics associated with the decomposition of garlic stalk at different temperatures, concentrations and durations were investigated. Stalk decomposition significantly increased the values of soil pH and electrical conductivity. In addition, total nitrogen and organic carbon concentration were significantly increased by decomposing stalks at 40°C, with a 5?100 ratio and for 10 or 60 days. The highest activities of sucrase, urease and alkaline phosphatase in soil were detected when stalk decomposition was performed at the lowest temperature (10°C), highest concentration (5?100), and shortest duration (10 or 20 days). The evidence presented here suggests that garlic stalk decomposition improves the quality of soil by altering the value of soil pH and electrical conductivity and by changing nutrient dynamics and soil enzyme activity, compared to the soil decomposition without garlic stalks.

Han, Xu; Cheng, Zhihui; Meng, Huanwen

2012-01-01

270

Acid rain and soil microbial activity: effects and their mechanisms  

SciTech Connect

In this investigation, our aim was to determine if acid rain affects soil microbial activity and to identify possible mechanisms of observed effects. A Sierran forest soil (pH 6.4) planted with Ponderosa pine seedlings was exposed to simulated rain (pH 2.0, 3.0, 4.0 and 5.6) with ionic composition reflecting that found in northern California, corresponding to 15 cm of precipitation over a 12-week period. After exposure, the soils were collected in two samples (top 1 cm and 4 to 5 cm), which were assayed separately for respiration and enzyme activities (urease, phosphatase, dehydrogenase, and arylsulfatase). Changes in microbial activity were most significant in surface soils. Only the pH 2.0 input caused inhibition of both respiration and enzyme activities. The overall microbial response to the pH 3.0 and 4.0 acid regimes was one of stimulation, although the response of individual enzymes was more varied. In surface soils receiving the pH 3.0 input, for example, urease activity was unaffected while arylsulfatase and phosphatase were increased and decreased respectively. Therefore, individual microbial processes will have different sensitivities to acid rain. Although changes in C-availability in the exposed soils are documented, changes in the supply of N are evaluated as the major mechanism through which simulated acid rain affects soil microbial activity.

Killham, K.; Firestone, M.K.; McColl, J.G.

1983-01-01

271

Biotoxicity assessment of pyrene in soil using a battery of biological assays.  

PubMed

A test battery, composed of a range of biological assays, was applied to evaluate the ecological health of soil aged for 69 days and spiked with a range of pyrene levels (1.04, 8.99, 41.5, 72.6, 136, and 399 ?g g(-1) dry soil; Soxhlet-extracted concentrations after 69 days of aging). Chinese cabbage (Brassica rapa), earthworm (Eisenia fetida), and bacteria (Vibrio fischeri) were used as test organisms to represent different trophic levels. Among the acute ecotoxicity bioassays used, the V. fischeri luminescence inhibition assay was the most sensitive indicator of pyrene toxicity. We observed >8 % light inhibition at the lowest concentration (1.04 ?g g(-1)) pyrene, and this inhibition increased to 60 % at 72.6 ?g g(-1). The sensitivity ranking for toxicity of the pyrene-contaminated soil in the present study was in the following decreasing order: root elongation of Chinese cabbage < earthworm mortality (14 days) < earthworm mortality (28 days) < luminescence inhibition (15 min) < luminescence inhibition (5 min). In addition, genotoxic effects of pyrene were also evaluated by using comet assay in E. fetida. The strong relationship between DNA damage and soil pyrene levels showed that comet assay is suitable for testing the genotoxicity of pyrene-polluted soil. In addition, tail moment was well correlated with soil pyrene levels (r (2) = 0.99). Thus, tail moment may be the most informative DNA-damage parameter representing the results of comet assay. Based on these results, the earthworm DNA damage assay and Microtox test are rapid and sensitive bioassays and can be used to assess the risk of soil with low to high levels of hydrocarbon pollution. Furthermore, an analysis of the toxic effects at several trophic levels is essential for a more comprehensive understanding of the damage caused by highly contaminated soil. PMID:22941450

Khan, Muhammad Imran; Cheema, Sardar Alam; Tang, Xianjin; Shen, Chaofeng; Sahi, Shahbaz Talib; Jabbar, Abdul; Park, Joonhong; Chen, Yingxu

2012-09-01

272

Microbial Diversity and Structure Are Drivers of the Biological Barrier Effect against Listeria monocytogenes in Soil  

PubMed Central

Understanding the ecology of pathogenic organisms is important in order to monitor their transmission in the environment and the related health hazards. We investigated the relationship between soil microbial diversity and the barrier effect against Listeria monocytogenes invasion. By using a dilution-to-extinction approach, we analysed the consequence of eroding microbial diversity on L. monocytogenes population dynamics under standardised conditions of abiotic parameters and microbial abundance in soil microcosms. We demonstrated that highly diverse soil microbial communities act as a biological barrier against L. monocytogenes invasion and that phylogenetic composition of the community also has to be considered. This suggests that erosion of diversity may have damaging effects regarding circulation of pathogenic microorganisms in the environment.

Vivant, Anne-Laure; Garmyn, Dominique; Maron, Pierre-Alain; Nowak, Virginie; Piveteau, Pascal

2013-01-01

273

Microbial Diversity and Structure Are Drivers of the Biological Barrier Effect against Listeria monocytogenes in Soil.  

PubMed

Understanding the ecology of pathogenic organisms is important in order to monitor their transmission in the environment and the related health hazards. We investigated the relationship between soil microbial diversity and the barrier effect against Listeria monocytogenes invasion. By using a dilution-to-extinction approach, we analysed the consequence of eroding microbial diversity on L. monocytogenes population dynamics under standardised conditions of abiotic parameters and microbial abundance in soil microcosms. We demonstrated that highly diverse soil microbial communities act as a biological barrier against L. monocytogenes invasion and that phylogenetic composition of the community also has to be considered. This suggests that erosion of diversity may have damaging effects regarding circulation of pathogenic microorganisms in the environment. PMID:24116193

Vivant, Anne-Laure; Garmyn, Dominique; Maron, Pierre-Alain; Nowak, Virginie; Piveteau, Pascal

2013-10-08

274

Development of biological soil crusts and their influence on soil hydrology in the recultivation area of lignite open-cast mining district in Lower Lusatia (Germany)  

NASA Astrophysics Data System (ADS)

Cyanobacteria, green algae, mosses and lichens are often the first colonizers of substrate and initial soil surfaces. They are an important factor of initial soil formation as they stabilize the substrate and decrease erosion processes. Biological soil crusts accumulate the initial soil organic matter and provide nitrogen fixation. Once settled, the crusts influence the soil water regime by delaying or limiting infiltration through enhanced water repellency. Aim of this study was to compare the influence of biological soil crusts on soil hydrology under conditions on various substrates and of different ages in recultivated areas of the open-cast mining district of Lower Lusatia (Brandenburg, NE Germany) with various recultivation aims. In Brandenburg (NE Germany), where the climate is transitional between oceanic and continental and the summers are characterized by generally low of precipitation (mean annual rainfall 559 mm, mean annual temperature 9.3° C) open landscapes provide ideal conditions for biological soil crusts, e. g. on mobile sand dunes in former military training areas and in recultivation areas related to open-cast mining with initial soil development. Here biological soil crusts are commonly found (Spröte et al., 2010). At five study sites in recultivation areas with different reclamation approaches (natural development, pine reforestation, birch reforestation) we defined four types of biological soil crusts: i) cyanobacterial and green algae crusts on the soil surface with no vegetation where dominating sand grains were physically stabilized in their contact zones by this crust type (type 1), ii) cyanobacteria and green algae partially filled in the matrix pores and enmeshed sand grains between sparse vegetation cover (type 2), iii) biological soil crusts with mosses which covered most of the surface between the vegetation (type 3) and (iv) with soil lichens (type 4). We investigated the development of the amount of chlorophyll a which is an indicator for biomass productivity and depends from the species composition and crust type, and the water repellency index which shows the influence of biological soil crusts on hydrological parameters. Additionally, organic matter content (dry combustion) as well as soil pH (soil: H2O = 1:2.5) were determined. Texture was analysed by wet sieving and fractionation pipette method. At all study sites and for all crust types soil pH ranged between 7.2 to 4.7 and decreased from type 1 to type 4. Soil organic matter and chlorophyll a concentrations ranged from 0.3 and 1.7% and from 0.95 to 16.44 mg m-2, respectively, and increased from type 1 to type 4. With few exceptions, water repellency indices ranging between 1.0 and 1.85, followed this trend. Constrarily, infiltration rates decreased from type 1 to type 4. The cause for limited infiltration is the swelling of extracellular polysaccharides in the biological soil crusts (Fischer et al., 2010) and the influence of the particle size distribution and porosity of the substrate with a relatively high content of silt and clay at some study sites. Fischer, T., Veste, M., Wiehe, W. & Lange, P. (2010): Water repellency and pore clogging at early succesional stages of microbiotic crusts on inland dunes, Brandenburg, NE Germany. - Catena, 80, 47-52. Spröte, R.,Fischer, T., Veste, M., Raab, T., Wiehe, W., Lange, P., Bens, O., Hüttl, R.F. (2010): Biological topsoil crusts at early successional stages on Quaternary substrates dumped by mining in Brandenburg, NE Germany. Géomorphologie: relief, processus, environnement 4/2010: 359-370.

Spröte, R.; Veste, M.; Fischer, T.; Raab, T.; Bens, O.; Hüttl, R. F.

2012-04-01

275

Effects of inoculated Microcoleus vaginatus on the structure and function of biological soil crusts of desert  

Microsoft Academic Search

Microcoleus vaginatus Gom., the dominant species in biological soil crusts (BSCs) in desert regions, plays a significant role in maintaining the\\u000a BSC structure and function. The BSC quality is commonly assessed by the chlorophyll a content, thickness, and compressive\\u000a strength. Here, we have studied the effect of different proportions of M. vaginatus, collected from the Gurbantunggut Desert in northwestern China,

Yunpu Zheng; Ming Xu; Jiancheng Zhao; Shuqing Bei; Lihua Hao

2011-01-01

276

Successional stages of biological soil crusts and their microstructure variability in Shapotou region (China)  

Microsoft Academic Search

In order to investigate succession of biological soil crusts (BSCs) and their microstructure variability, we conducted this\\u000a work in Shapotou revegetation region at the southeast edge of Tengger Deser. The results showed that BSCs generally succeeded\\u000a as a pathway of “Algae crusts, algae–lichen crusts, lichen crusts, lichen–moss crusts and moss crusts”. Occasionally mosses\\u000a directly occurred on algae crusts, and BSCs

Shubin LanLi; Li Wu; Delu Zhang; Chunxiang Hu

277

A predictive model of spatial distribution of Biological Soil Crust in the Sahel from local to regional scale  

NASA Astrophysics Data System (ADS)

The Sahel region in West Africa is highly vulnerable facing soil degradation due to the harsh climatic conditions, with variable rainfall, and high anthropic pressure on land use. In Sahel, as in other arid environments, biological soil crusts are present over a large area. The BIOCRUST project focuses on the use of BSC as an indicator of environmental quality in the context of climate change and human activities pressures and on providing useful informations for best management practices for the Sahelian environment. To this end, a characterisation of BSC is required first at a local level based on the use of Very High Resolution satellite imagery. Two detailed field campaigns were undertaken to identify key variables indicative of the presence of biological soil crusts. A Statistic analysis ascertained that vegetation cover, land use, soil types and rainfall were the most significant variables to consider. From these, a predictive model of the spatial distribution of BSC was developed, based on a logistic regression. The extraction of the variables from the satellite imagery makes it possible to run the prediction model for 2 catchment areas of about 50km2 each situated in Niger on a North South transect. With a view to apply the prediction model to the central part of the Sahel scale, the same methodology was used with Medium Resolution satellite imagery and field data collected on a North South transect in Niger and Burkina Faso. Preliminary results indicate that the model is applicable at regional scale and show the potential spatial distribution of BSCs over a large portion of the Central part of the Sahel region.

Beaugendre, N.; Choné, A.; Sannier, C.; Desprats, J. F.; Cerdan, O.; Valentin, C.; Malam Issa, O.; Rajot, J. L.

2012-04-01

278

Spatial variation in soil active-layer geochemistry across hydrologic margins in polar desert ecosystems  

NASA Astrophysics Data System (ADS)

Polar deserts are characterized by severe spatial-temporal limitations of liquid water. In soil active layers of the Antarctic Dry Valleys, liquid water is infrequently available over most of the arid terrestrial landscape. However, soils and sediments on the margins of glacial melt-water streams and lakes are visibly wet during the brief Austral summer when temperatures permit the existence of liquid water. We examined the role of these hydrologic margins as preferential zones for the transformation and transport of nutrient elements and solutes in an environment where geochemical weathering and biological activity is strictly limited by the dearth of liquid water. We report on hydropedological investigations of aquatic-terrestrial transition zones adjacent to 11 stream and lake systems in the Antarctic Dry Valleys. Our results show that wetted zones extended 1-11 m from the edges of lotic and lentic systems. While capillary demand and surface evaporation drive a one-way flux of water through these zones, the scale of these transition zones is determined by the topography and physical characteristics of the surrounding soils. Nutrient concentrations and fluxes appear to be influenced by both the hydrology and microbial-mediated biogeochemical processes. Salt concentrations are enriched near the distal boundary of the wetted fronts due to evapo-concentration of pore water in lake margin soils, while organic matter, ammonium and phosphate concentrations are highest in stream channel sediments where potential for biological activity is greatest. Thus, in the Antarctic Dry Valleys, intermittently wet soils on the margins of streams and lakes are important zones of both geochemical cycling and biological activity.

Barrett, J. E.; Gooseff, M. N.; Takacs-Vesbach, C.

2009-05-01

279

Spatial variation in soil active-layer geochemistry across hydrologic margins in polar desert ecosystems  

NASA Astrophysics Data System (ADS)

Polar deserts are characterized by severe spatial-temporal limitations of liquid water. In soil active layers of the Antarctic Dry Valleys, liquid water is infrequently available over most of the arid terrestrial landscape. However, soils on the margins of glacial melt-water streams and lakes are visibly wet during the brief Austral summer when temperatures permit the existence of liquid water. We examined the role of these hydrologic margins as preferential zones for the transformation and transport of nutrient elements and solutes in an environment where geochemical weathering and biological activity is strictly limited by the dearth of liquid water. We report on hydropedological investigations of aquatic-terrestrial transition zones adjacent to 11 stream and lake systems in the Antarctic Dry Valleys. Our results show that wetted zones extended 1-11 m from the edges of lotic and lentic systems. While capillary demand and surface evaporation drive a one-way flux of water through these zones, the scale of these transition zones is determined by the topography and physical characteristics of the surrounding soils. Nutrient concentrations and fluxes appear to be influenced by both the hydrology and microbial-mediated biogeochemical processes. Salt concentrations are enriched near the distal boundary of the wetted fronts due to evapo-concentration of pore water in lake margin soils, while organic matter, ammonium and phosphate concentrations are highest in stream channel sediments where potential for biological activity is greatest. Thus, in the Antarctic Dry Valleys, intermittently wet soils on the margins of streams and lakes are important zones of both geochemical cycling and biological activity.

Barrett, J. E.; Gooseff, M. N.; Takacs-Vesbach, C.

2009-12-01

280

Controls of biological soil crust cover and composition shift with succession in sagebrush shrub-steppe  

USGS Publications Warehouse

Successional stage may determine strength and causal direction of interactions among abiotic and biotic factors; e.g., species that facilitate the establishment of other species may later compete with them. We evaluated multivariate hypotheses about abiotic and biotic factors shaping biological soil crusts (BSCs) in early and late successional stages. We surveyed vegetation and BSC in the shrub-steppe ecosystem of the Columbia Basin. We analyzed the relationships with bryophyte and lichen covers using structural equation models, and analyzed the relationships with BSC composition using Indicator Species Analysis and distance-based linear models. Cover, indicator species, and composition varied with successional stage. Increasing elevation and bryophyte cover had higher lichen cover early in succession; these relationships were negative in the later successional stage. Lichen cover did not appear to impede B. tectorum cover, but B. tectorum appeared to strongly negatively affect lichen cover in both stages. Biological soil crust composition varied with bunchgrass cover in the early successional stage, but with elevation and B. tectorum cover later in succession. Our findings support the hypotheses that as succession progresses, the strength and direction of certain community interactions shift, and B. tectorum leads to reductions in biological soil crust cover regardless of successional stage.

Dettweiler-Robinson, E.; Bakker, J. D.; Grace, J. B.

2013-01-01

281

Stratification of Soil Organic Matter and Potential Impact on Water Runoff Quality  

Microsoft Academic Search

Soil quality is a concept based on the premise that management can deteriorate, stabilize, or improve soil ecosystem functions. Soil organic matter is a key component of soil quality that sustains many key soil functions by providing the energy, substrates, and biological diversity to support biological activity, which affects (1) aggregation (important for habitat space, oxygen supply, and preventing soil

Alan J. Franzluebbers

282

Soil Inorganic Carbon in Deserts: Active Carbon Sink or Inert Reservoir?  

NASA Astrophysics Data System (ADS)

Soil inorganic carbon is the third largest C pool in the active global carbon cycle, containing at least 800 petagrams of carbon. Although carbonate dissolution-precipitation reactions have been understood for over a century, the role of soil inorganic carbon in carbon sequestration, and in particular pedogenic carbonate, is a deceptively complex process because it involves interdependent connections among climate, plants, microorganisms, silicate minerals, soil moisture, pH, and Ca supply via rain, dust, or in situ weathering. An understanding of soil inorganic carbon as a sink or reservoir also requires examination of the system at local to continental scales and at seasonal to millennial time scales. In desert soils studied in North America, carbon isotope ratios and radiocarbon dates were measured in combination with electron microscopy, lab and field experiments with biological calcite formation, and field measurements of carbon dioxide emissions. These investigations reveal that soil inorganic carbon is both an active sink and a inert reservoir depending on the spatial and temporal scale and source of calcium.

Monger, H. C.; Cole, D. R.

2011-12-01

283

Ficus carica L. (Moraceae): Phytochemistry, Traditional Uses and Biological Activities  

PubMed Central

This paper describes the botanical features of Ficus carica L. (Moraceae), its wide variety of chemical constituents, its use in traditional medicine as remedies for many health problems, and its biological activities. The plant has been used traditionally to treat various ailments such as gastric problems, inflammation, and cancer. Phytochemical studies on the leaves and fruits of the plant have shown that they are rich in phenolics, organic acids, and volatile compounds. However, there is little information on the phytochemicals present in the stem and root. Reports on the biological activities of the plant are mainly on its crude extracts which have been proven to possess many biological activities. Some of the most interesting therapeutic effects include anticancer, hepatoprotective, hypoglycemic, hypolipidemic, and antimicrobial activities. Thus, studies related to identification of the bioactive compounds and correlating them to their biological activities are very useful for further research to explore the potential of F. carica as a source of therapeutic agents.

Mawa, Shukranul; Husain, Khairana; Jantan, Ibrahim

2013-01-01

284

Variability of soil carbon sequestration capability and microbial activity of different types of salt marsh soils at Chongming Dongtan  

Microsoft Academic Search

Variations in the soil carbon sequestration capability of different types of salt marsh soils at Chongming Dongtan and its influencing factors were studied by analyzing the soil organic carbon (SOC) content, organic matter input and microbial activities. The results indicated that the total SOC content at Area A (southeast of Dongtan, sandy soil with Phragmites communis) was only 46.11% of

Yan-li Li; Lei Wang; Wen-quan Zhang; Shi-ping Zhang; Hong-li Wang; Xiao-hua Fu; Yi-quan Le

2010-01-01

285

Variation in denitrification activity with soil depth under pasture  

Microsoft Academic Search

Factors affecting the variation in soil denitrification activity with depth, at different times of the year, were studied in a well-drained sandy loam and a poorly-drained silt loam under pasture, using the denitrification enzyme activity assay. Additions of NO3?–N or glucose–C to saturated soils under anaerobic conditions were used to identify which of these factors most limited denitrification. Field denitrification

J. Luo; R. W. Tillman; R. E. White; P. R. Ball

1998-01-01

286

Biologic activity of lipid-coated quartz dust. Progress report  

Microsoft Academic Search

The biological activity of quartz dust coated with endogenous lipids was investigated. The theory under study was that the lipoidic coating would render the quartz particles nonwettable, and therefore biologically inert. Lipid coated and uncoated dust was dispersed in water and injected into rats intratracheally. The animals were sacrificed 2 days, 6 months or 10 months following injection. No significant

Tuma

1971-01-01

287

Joint bioaccumulation and joint biological activity as ecotoxicological risk indicators  

Microsoft Academic Search

In this contribution, mathematical formulae for the estima- tion of thusly defined indicators are presented. Strategies for assessing biological activity from simultaneous mea- surements of biological effects and internal exposure are given special attention. Relevance of transformation products The question which of the known or suspected transforma- tion products should be included in an assessment of joint persistence (4), secondary

J. Ranke

288

Accommodating Students with Disabilities in Soil Science Activities  

NSDL National Science Digital Library

Soil science education is lacking in terms of accommodations for persons with disabilities to the extent that these individuals are often excluded from soil science activities in school, and from careers in the discipline. This article describes a study whose goal was to develop accommodations to the soils protocols currently being used in the GLOBE (Global Learning Observations to Benefit the Environment) program. These new materials are based on the principles of universal design in education (UDE), so that GLOBE activities and materials can be accessible to a broad range of students, including students with disabilities.

Langley-Turnbaugh, S.

289

ASSESSMENT OF GENOTOXIC ACTIVITY OF PETROLEUM HYDROCARBON-BIOREMEDIATED SOIL  

SciTech Connect

The relationship between toxicity and soil contamination must be understood to develop reliable indicators of environmental restoration for bioremediation. Two bacterial rapid bioassays: SOS chromotest and umu-test with and without metabolic activation (S-9 mixture) were used to evaluate genotoxicity of petroleum hydrocarbon-contaminated soil following bioremediation treatment. The soil was taken from an engineered biopile at the Czor Polish oil refinery. The bioremediation process in the biopile lasted 4 years, and the toxicity measurements were done after this treatment. Carcinogens detected in the soil, polyaromatic hydrocarbons (PAHs), were reduced to low concentrations (2 mg/kg dry wt) by the bioremediation process. Genotoxicity was not observed for soils tested with and without metabolic activation by a liver homogenate (S-9 mixture). However, umu-test was more sensitive than SOS-chromotest in the analysis of petroleum hydrocarbon-bioremediated soil. Analytical results of soil used in the bioassays confirmed that the bioremediation process reduced 81 percent of the petroleum hydrocarbons including PAHs. We conclude that the combined test systems employed in this study are useful tools for the genotoxic examination of remediated petroleum hydrocarbon-contaminated soil.

BRIGMON, ROBIN

2004-10-20

290

Active and total prokaryotic communities in dryland soils.  

PubMed

The relationship between total and metabolically active soil microbial communities can change drastically with environment. In dry lands, water availability is a key factor limiting cells' activity. We surveyed the diversity of total and active Archaea and Bacteria in soils ranging from arid desert to Mediterranean forests. Thirty composited soil samples were retrieved from five sites along a precipitation gradient, collected from patches located between and under the dominant perennial plant at each site. Molecular fingerprinting was used to site-sort the communities according of their 16S rRNA genes (total community) and their rRNA (active community) amplified by PCR or RT-PCR from directly extracted soil nucleic acids. The differences between soil samples were much higher in total rather than active microbial communities: differences in DNA fingerprints between sites were 1.2 and 2.5 times higher than RNA differences (for Archaea and Bacteria, respectively). Patch-type discrepancies between DNA fingerprints were on average 2.7-19.7 times greater than RNA differences. Moreover, RNA-based community patterns were highly correlated with soil moisture but did not necessarily follow spatial distribution pattern. Our results suggest that in water-limited environments, the spatial patterns obtained by the analysis of active communities are not as robust as those drawn from total communities. PMID:23730745

Angel, Roey; Pasternak, Zohar; Soares, M Ines M; Conrad, Ralf; Gillor, Osnat

2013-06-26

291

TECHNOLOGY EVALUATION REPORT: PILOT-SCALE DEMONSTRATION OF A SLURRY-PHASE BIOLOGICAL REACTOR FOR CREOSOTE-CONTAMINATED SOIL  

EPA Science Inventory

This report documents a pilot-scale test of a slurry-phase biological reactor for treatment of creosote-contaminated soil. he technology used was a reactor system in which an aqueous slurry of soil was mixed with appropriate nutrients and seeded with microorganisms to enhance the...

292

Effects of biological soil crusts on seed germination of four endangered herbs in a xeric Florida shrubland during drought  

Microsoft Academic Search

Soil crusts of rosemary scrubs in south-central Florida were examined for effects on seed germination of four herbs that are killed by fire and must recruit from seed: Eryngium cuneifolium (Apiaceae), Hypericum cumulicola (Hypericaceae), Polygonella basiramia (Polygonaceae), and Paronychia chartacea ssp. chartacea (Caryophyllaceae). Biological soil crusts in these sites are dominated by algae, cyanobacteria, fungi, and bacteria. Because crusts can

Christine V. Hawkes

2004-01-01

293

Long-term organic farming fosters below and aboveground biota: Implications for soil quality, biological control and productivity  

Microsoft Academic Search

Organic farming may contribute substantially to future agricultural production worldwide by improving soil quality and pest control, thereby reducing environmental impacts of conventional farming. We investigated in a comprehensive way soil chemical, as well as below and aboveground biological parameters of two organic and two conventional wheat farming systems that primarily differed in fertilization and weed management strategies. Contrast analyses

Klaus Birkhofer; T. Martijn Bezemer; Jaap Bloem; Michael Bonkowski; Søren Christensen; David Dubois; Fleming Ekelund; Andreas Fließbach; Lucie Gunst; Katarina Hedlund; Paul Mäder; Juha Mikola; Christophe Robin; Heikki Setälä; Fabienne Tatin-Froux; Wim H. Van der Putten; Stefan Scheu

2008-01-01

294

Biology Research Activities: Teacher's Edition (with Answers).  

ERIC Educational Resources Information Center

|This book is part of the series "Explorations in Science" which contains enrichment activities for the general science curriculum. Each book in the series contains innovative and traditional projects for both the bright and average, the self-motivated, and those who find activity motivating. Each activity is self-contained and provides everything…

Newman, Barbara

295

Biologically Enhanced Oxygen Transfer in the Activated Sludge Process.  

National Technical Information Service (NTIS)

Biologically enhanced oxygen transfer has been a hypothesis to explain observed oxygen transfer rates in activated sludge systems that were well above that predicted from aerator clean-water testing. The enhanced oxygen transfer rates were based on tests ...

J. S. Mueller H. D. Stensel R. C. Brenner

1990-01-01

296

Quantitative analysis of the new biologically active natural substance shunlite  

Microsoft Academic Search

Methods for the quantitative determination of chemical elements contained in shunlite — a new biologically active natural\\u000a substance — have been developed. The proposed methods are characterized by high accuracy and reproducibility.

O. Yu. Vasil’eva; M. S. Goizman; G. B. Tikhomirova; A. S. Berlyand; A. S. Alikhanyan; A. V. Shevyakov

2007-01-01

297

Organic matter, microbial biomass and enzyme activity of soils under different crop rotations in the tropics  

Microsoft Academic Search

Soil organic matter level, soil microbial biomass C, ninhydrin-N, C mineralization, and dehydrogenase and alkaline phosphatase\\u000a activity were studied in soils under different crop rotations for 6 years. Inclusion of a green manure crop of Sesbania aculeata in the rotation improved soil organic matter status and led to an increase in soil microbial biomass, soil enzyme activity\\u000a and soil respiratory

K. Chander; S. Goyal; M. C. Mundra; K. K. Kapoor

1997-01-01

298

Effect of substrate concentration, soil moisture, and organic amendments on urease activity of soil containing variable nickel amounts  

Microsoft Academic Search

Effects of substrate concentration, soil moisture, and type of added organic material on urease activity of soil containing variable Ni content were studied. Urease activity ranged from 7.45 to 12.66 ?g N hydrolyzed g soil h at 37°C. Activity was higher in unpolluted than in Ni?polluted soil and increased linearly with increasing substrate concentration. It also increased with increasing moisture

R. S. Antil; A. P. Gupta; R. P. Narwal

1993-01-01

299

Effects of Long-Term Combined Application of Organic and Mineral Fertilizers on Microbial Biomass, Soil Enzyme Activities and Soil Fertility  

Microsoft Academic Search

Soil health is important for the sustainable development of terrestrial ecosystem. In this paper, we studied the relationship between soil quality and soil microbial properties such as soil microbial biomass and soil enzyme activities in order to illustrate the function of soil microbial properties as bio-indicators of soil health. In this study, microbial biomass C and N contents (Cmic &

Juan LI; Bing-qiang ZHAO; Xiu-ying LI; Rui-bo JIANG; So Hwat Bing

2008-01-01

300

Biological Activity of Curcuminoids Isolated from Curcuma longa  

Microsoft Academic Search

Curcumin is the most important fraction of turmeric which is responsible for its biological activity. In this study, isolation and biological assessment of turmeric and curcumin have been discussed against standard bacterial and mycobacterial strains such as E.coli , S.aureus, E.feacalis, P.aeuroginosa, M.smegmatis, M.simiae, M.kansasii, M. terrae, M.szulgai and the fungi Candida albicans. The antioxidant activity of curcumin and turmeric

Simay Çõkrõkçõ; Erkan Moziolu; Hasibe Yõlmaz

301

Biological activity and characterization of nucleopolyhedrovirus isolates of Spodoptera litura  

Microsoft Academic Search

Geographical isolates ofSpodoptera litura (Fabricius) (Noctuidae: Lepidoptera) nucleopolyhedrovirus (SpltNPV), collected from different parts of India and maintained\\u000a at Tamil Nadu Agricultural University, were compared for their biological activity and subjected to Restriction Endonuclease\\u000a (REN) analysis. Neonate and second instar bioassay studies revealed similarity in biological activity as shown by the overlapping\\u000a fiducial limits of LC50 values. However, there were differences

C. M. Senthil Kumar; R. J. Rabindra; N. Sathiah

2006-01-01

302

Synthesis and biological activity of flavanone derivatives  

Microsoft Academic Search

A series of new flavanone derivatives of farrerol was synthesized by a convenient method. The in vitro anti-tumor activity of these compounds was evaluated against human Bel-7402, HL-60, BGC-823 and KB cell lines, the protein tyrosine kinase (PTK) inhibitor activity was also tested. Their cytoprotective activity was tested using hydrogen peroxide (H2O2)-induced injury in human umbilical vein endothelial cells. Their

Lei Shi; Xiu E Feng; Jing Rong Cui; Lian Hua Fang; Guan Hua Du; Qing Shan Li

2010-01-01

303

Depth distribution of soil organic carbon as a signature of soil quality  

Technology Transfer Automated Retrieval System (TEKTRAN)

Soil organic matter is a key component of soil quality that sustains many key soil functions by providing the energy, substrates, and biological diversity to support biological activity, which affects aggregation (important for habitat space, oxygen supply, and preventing soil erosion), infiltration...

304

Biological Activities of Novel Gyrase Inhibitors of the Aminocoumarin Class  

Microsoft Academic Search

Thirty-one aminocoumarin antibiotics derived from mutasynthesis experiments were investigated for their biological activities. Their inhibitory activities toward Escherichia coli DNA gyrase were determined in two different in vitro assays: an ATPase assay and a DNA supercoiling assay. The assays gave a similar rank order of the activities of the compounds tested, although the absolute 50% inhibitory concentrations (IC50s) obtained in

Christine Anderle; Martin Stieger; Matthew Burrell; Stefan Reinelt; Anthony Maxwell; Malcolm Page; Lutz Heide

2008-01-01

305

Biofilm processes in biologically active carbon water purification  

Microsoft Academic Search

This review paper serves to describe the composition and activity of a biologically active carbon (BAC) biofilm used in water purification. An analysis of several physical–chemical, biochemical and microbiological methods (indicators) used to characterize the BAC biofilm's composition and activity is provided. As well, the ability of the biofilm to remove and biodegrade waterborne organic substances and pollutants will be

David R. Simpson

2008-01-01

306

Differential Nutrient Limitation of Soil Microbial Biomass and Metabolic Quotients (qCO2): Is There a Biological Stoichiometry of Soil Microbes?  

PubMed Central

Background Variation in microbial metabolism poses one of the greatest current uncertainties in models of global carbon cycling, and is particularly poorly understood in soils. Biological Stoichiometry theory describes biochemical mechanisms linking metabolic rates with variation in the elemental composition of cells and organisms, and has been widely observed in animals, plants, and plankton. However, this theory has not been widely tested in microbes, which are considered to have fixed ratios of major elements in soils. Methodology/Principal Findings To determine whether Biological Stoichiometry underlies patterns of soil microbial metabolism, we compiled published data on microbial biomass carbon (C), nitrogen (N), and phosphorus (P) pools in soils spanning the global range of climate, vegetation, and land use types. We compared element ratios in microbial biomass pools to the metabolic quotient qCO2 (respiration per unit biomass), where soil C mineralization was simultaneously measured in controlled incubations. Although microbial C, N, and P stoichiometry appeared to follow somewhat constrained allometric relationships at the global scale, we found significant variation in the C?N?P ratios of soil microbes across land use and habitat types, and size-dependent scaling of microbial C?N and C?P (but not N?P) ratios. Microbial stoichiometry and metabolic quotients were also weakly correlated as suggested by Biological Stoichiometry theory. Importantly, we found that while soil microbial biomass appeared constrained by soil N availability, microbial metabolic rates (qCO2) were most strongly associated with inorganic P availability. Conclusions/Significance Our findings appear consistent with the model of cellular metabolism described by Biological Stoichiometry theory, where biomass is limited by N needed to build proteins, but rates of protein synthesis are limited by the high P demands of ribosomes. Incorporation of these physiological processes may improve models of carbon cycling and understanding of the effects of nutrient availability on soil C turnover across terrestrial and wetland habitats.

Hartman, Wyatt H.; Richardson, Curtis J.

2013-01-01

307

Comparative Resistance and Resilience of Soil Microbial Communities and Enzyme Activities in Adjacent Native Forest and Agricultural Soils  

Microsoft Academic Search

Degradation of soil properties following deforestation and long-term soil cultivation may lead to decreases in soil microbial\\u000a diversity and functional stability. In this study, we investigated the differences in the stability (resistance and resilience)\\u000a of microbial community composition and enzyme activities in adjacent soils under either native tropical forest (FST) or in\\u000a agricultural cropping use for 14 years (AGR). Mineral soil

Guilherme Chaer; Marcelo Fernandes; David Myrold; Peter Bottomley

2009-01-01

308

Effect of substrate concentration, soil moisture, and organic materials on urease activity of soil contaminated with lead  

Microsoft Academic Search

A laboratory experiment was carried out in order to study the effect of substrate concentration, soil moisture, and type of organic materials on urease activity of soils containing variable lead (Pb) contents. Various Pb levels ranging from 52.1 – 589.9 mg kg were created by mixing uncontaminated (containing 52.1 mg Pb kg soil) and contaminated (containing 589.9 mg Pb kg soil) soils in different proportions.

R. S. Antil; M. K. Mahata; R. P. Narwal

2006-01-01

309

Activation Energy of Extracellular Enzymes in Soils from Different Biomes  

PubMed Central

Enzyme dynamics are being incorporated into soil carbon cycling models and accurate representation of enzyme kinetics is an important step in predicting belowground nutrient dynamics. A scarce number of studies have measured activation energy (Ea) in soils and fewer studies have measured Ea in arctic and tropical soils, or in subsurface soils. We determined the Ea for four typical lignocellulose degrading enzymes in the A and B horizons of seven soils covering six different soil orders. We also elucidated which soil properties predicted any measurable differences in Ea. ?-glucosidase, cellobiohydrolase, phenol oxidase and peroxidase activities were measured at five temperatures, 4, 21, 30, 40, and 60°C. Ea was calculated using the Arrhenius equation. ?-glucosidase and cellobiohydrolase Ea values for both A and B horizons in this study were similar to previously reported values, however we could not make a direct comparison for B horizon soils because of the lack of data. There was no consistent relationship between hydrolase enzyme Ea and the environmental variables we measured. Phenol oxidase was the only enzyme that had a consistent positive relationship between Ea and pH in both horizons. The Ea in the arctic and subarctic zones for peroxidase was lower than the hydrolases and phenol oxidase values, indicating peroxidase may be a rate limited enzyme in environments under warming conditions. By including these six soil types we have increased the number of soil oxidative enzyme Ea values reported in the literature by 50%. This study is a step towards better quantifying enzyme kinetics in different climate zones.

Steinweg, J. Megan; Jagadamma, Sindhu; Frerichs, Joshua; Mayes, Melanie A.

2013-01-01

310

Successional stage of biological soil crusts: an accurate indicator of ecohydrological condition  

USGS Publications Warehouse

Biological soil crusts are a key component of many dryland ecosystems. Following disturbance, biological soil crusts will recover in stages. Recently, a simple classification of these stages has been developed, largely on the basis of external features of the crusts, which reflects their level of development (LOD). The classification system has six LOD classes, from low (1) to high (6). To determine whether the LOD of a crust is related to its ecohydrological function, we used rainfall simulation to evaluate differences in infiltration, runoff, and erosion among crusts in the various LODs, across a range of soil depths and with different wetting pre-treatments. We found large differences between the lowest and highest LODs, with runoff and erosion being greatest from the lowest LOD. Under dry antecedent conditions, about 50% of the water applied ran off the lowest LOD plots, whereas less than 10% ran off the plots of the two highest LODs. Similarly, sediment loss was 400 g m-2 from the lowest LOD and almost zero from the higher LODs. We scaled up the results from these simulations using the Rangeland Hydrology and Erosion Model. Modelling results indicate that erosion increases dramatically as slope length and gradient increase, especially beyond the threshold values of 10 m for slope length and 10% for slope gradient. Our findings confirm that the LOD classification is a quick, easy, nondestructive, and accurate index of hydrological condition and should be incorporated in field and modelling assessments of ecosystem health.

Belnap, Jayne; Wilcox, Bradford P.; Van Scoyoc, Matthew V.; Phillips, Susan L.

2013-01-01

311

Evidence for micronutrient limitation of biological soil crusts: Importance to arid-lands restoration  

USGS Publications Warehouse

Desertification is a global problem, costly to national economies and human societies. Restoration of biological soil crusts (BSCs) may have an important role to play in the reversal of desertification due to their ability to decrease erosion and enhance soil fertility. To determine if there is evidence that lower fertility may hinder BSC recolonization, we investigated the hypothesis that BSC abundance is driven by soil nutrient concentrations. At a regional scale (north and central Colorado Plateau, USA), moss and lichen cover and richness are correlated with a complex water-nutrient availability gradient and have approximately six-fold higher cover and approximately two-fold higher species richness on sandy soils than on shale-derived soils. At a microscale, mosses and lichens are overrepresented in microhabitats under the north sides of shrub canopies, where water and nutrients are more available. At two spatial scales, and at the individual species and community levels, our data are consistent with the hypothesis that distributions of BSC organisms are determined largely by soil fertility. The micronutrients Mn and Zn figured prominently and consistently in the various analyses, strongly suggesting that these elements are previously unstudied limiting factors in BSC development. Structural-equation modeling of our data is most consistent with the hypothesis of causal relationships between the availability of micronutrients and the abundance of the two major nitrogen (N) fixers of BSCs. Specifically, higher Mn availability may determine greater Collema tenax abundance, and both Mn and Zn may limit Collema coccophorum; alternative causal hypotheses were less consistent with the data. We propose experimental trials of micronutrient addition to promote the restoration of BSC function on disturbed lands. Arid lands, where BSCs are most prevalent, cover ???40% of the terrestrial surface of the earth; thus the information gathered in this study is potentially useful in many places worldwide. ?? 2005 by the Ecological Society of America.

Bowker, M. A.; Belnap, J.; Davidson, D. W.; Phillips, S. L.

2005-01-01

312

Seeding of Large Areas with Biological Soil Crust Starter Culture Formulations: Using an Aircraft Disbursable Granulate to Increase Stability, Fertility and CO2 Sequestration on a Landscape Scale  

Microsoft Academic Search

Microbial consortia found in biological soil crusts can mitigate climate change and assist agriculture. Cyanobacteria and other biological soil crust (BSC) microorganisms have fulfilled essential roles in the global ecosystem by fertilizing arid soils and stabilizing them from wind and water erosion. Using only photosynthesis, ambient minerals and water, these microorganisms directly capture atmospheric carbon dioxide and nitrogen. As the

James T. Sears; Bharath Prithiviraj

2012-01-01

313

Effects of fertilization on bacterial community structure and function in a black soil of Dehui region estimated by Biolog and PCR-DGGE methods  

Microsoft Academic Search

Soil microbial community structure and function are commonly used as indicators for soil quality and fertility. In this paper, the bacterial community structure and function in a black soil of Dehui region influenced by fertilization were investigated by Biolog and PCR-DGGE (polymerase chain reaction-denaturing gradient gel electrophoresis) methods. Biolog examination showed that substrate richness and catabolic diversities of bacterial communities

Wang Guanghua; Liu Junjie; Qi Xiaoning; Jin Jian; Wang Yang; Liu Xiaobing

2008-01-01

314

Soil organic matter dynamics and microbial activity in a cropland and soil treated with wood ash containing charcoal  

NASA Astrophysics Data System (ADS)

Wood ash is generated as a by-product of biomass combustion in power plants, and can be applied to soil to improve nutritional status and crop production. The application of mixed wood ash, a mixture of ash and charcoal, may also improve the SOM content and quality. The charcoal contained in mixed wood ash is a pyrogenic organic material, a heterogeneous mixture of thermally altered polymers with aromatic domains. This structure may favour oxidation, facilitating further microbial attack and generation of new SOM compounds. In addition, accelerated C mineralization of this material may also be due to the priming effect of the rhizosphere, which may even enhance the decomposition of more recalcitrant SOM. The study was carried out in a field devoted to cereal crops during the last few decades. The soil was acidic (pH 4.5) with a low SOC content (3 %). The experiment was based on a randomised block design with four replicates. Each block included the following four treatments: Control, 16 Mg fly wood ash, 16 Mg mixed wood ash and 32 Mg mixed wood ash ha-1. The ash used in the study was obtained from a thermal power plant and was mainly derived from the combustion of Pinus radiata bark. The changes in SOM were monitored over two years by solid state 13C CPMAS NMR and Differential Scanning Calorimetry (DSC). The changes in microbial activity were studied by analysis of microbial biomass C and basal respiration. The soil bacterial community was studied by the Biolog method. Both 13 C-CPMAS NMR spectra and DSC curves revealed that the SOM in the treated soils displayed a higher degree of aromaticity than in the untreated soils, indicating a gain in more stable SOM compounds. However, both methods also revealed increases in other labile C compounds. Microbial biomass and soil respiration increased significantly as a result of these effects and possibly also due to a priming effect. The treatments also led to increases in the functional diversity indices. The amended soils showed greater utilization of substrate and a faster response. The ability of soil bacteria to utilize different C resources was also greatly altered. Greater utilization of carbohydrates, carboxylic acids, amino acid and amines was observed.

Omil, B.; Fonturbel, M. T.; Vega, J. A.; Balboa, M. A.; Merino, A.

2012-04-01

315

Metal Toxicity Affects Fungal and Bacterial Activities in Soil Differently  

PubMed Central

Although the toxic effect of heavy metals on soil microorganism activity is well known, little is known about the effects on different organism groups. The influence of heavy metal addition on total, bacterial, and fungal activities was therefore studied for up to 60 days in a laboratory experiment using forest soil contaminated with different concentrations of Zn or Cu. The effects of the metals differed between the different activity measurements. During the first week after metal addition, the total activity (respiration rate) decreased by 30% at the highest level of contamination and then remained stable during the 60 days of incubation. The bacterial activity (thymidine incorporation rate) decreased during the first days with the level of metal contamination, resulting in a 90% decrease at the highest level of contamination. Bacterial activity then slowly recovered to values similar to those of the control soil. The recovery was faster when soil pH, which had decreased due to metal addition, was restored to control values by liming. Fungal activity (acetate-in-ergosterol incorporation rate) initially increased with the level of metal contamination, being up to 3 and 7 times higher than that in the control samples during the first week at the highest levels of Zn and Cu addition, respectively. The positive effect of metal addition on fungal activity then decreased, but fungal activity was still higher in contaminated than in control soil after 35 days. This is the first direct evidence that fungal and bacterial activities in soil are differently affected by heavy metals. The different responses of bacteria and fungi to heavy metals were reflected in an increase in the relative fungal/bacterial ratio (estimated using phospholipid fatty acid analysis) with increased metal load.

Rajapaksha, R. M. C. P.; Tobor-Kaplon, M. A; Baath, E.

2004-01-01

316

Changes in populations of soil microorganisms, nematodes, and enzyme activity associated with application of powdered pine bark  

Microsoft Academic Search

Evaluation of enzyme activities in combination with taxonomic analyses may help define the mechanisms involved in microbial decomposition of orgaic amendments and biological control of soilborne pathogens. In this study, powdered pine bark was added to nematode-infested soil at rates of 0, 5, 10, 15, 20, 25, 30, 35, 40, 45, and 50 g kg-1. Total fungal populations did not

Nancy Kokalis-Burelle; Rodrigo Rodríguez-Kábana

1994-01-01

317

Acid rain and soil microbial activity: effects and their mechanisms  

Microsoft Academic Search

In this investigation, the aim was to determine if acid rain affects soil microbial activity and to identify possible mechanisms of observed effects. A Sierran forest soil (pH 6.4) planted with Ponderosa pine seedings was exposed to simulated rain (pH 2.0, 3.0, 4.0, and 5.6) with ionic composition reflecting that found in northern California, corresponding to 15 cm of precipitation

K. Killham; M. K. Firestone; J. G. McColl

2009-01-01

318

Acid rain and soil microbial activity: effects and their mechanisms  

Microsoft Academic Search

In this investigation, our aim was to determine if acid rain affects soil microbial activity and to identify possible mechanisms of observed effects. A Sierran forest soil (pH 6.4) planted with Ponderosa pine seedlings was exposed to simulated rain (pH 2.0, 3.0, 4.0 and 5.6) with ionic composition reflecting that found in northern California, corresponding to 15 cm of precipitation

K. Killham; M. K. Firestone; J. G. McColl

1983-01-01

319

Tillage and residue management effects on arylamidase activity in soils  

Microsoft Academic Search

Recent interest in soil tillage and residue management has focused on low-input sustainable agriculture. This study was conducted to investigate the effect of three tillage systems (no-till, chisel plow, and moldboard plow) and four residue placements (bare, normal, mulch, and double mulch) on a most recently detected enzyme in soils, arylamidase activity. This enzyme catalyzes the hydrolysis of an N-terminal

V. Acosta-Martínez; M. A. Tabatabai

2001-01-01

320

Molecular and biological diagnostic tests for monitoring benzimidazole resistance in human soil-transmitted helminths.  

PubMed

In endemic countries with soil-transmitted helminths mass drug administration with albendazole or mebendazole are being implemented as a control strategy. However, it is well known in veterinary helminths that the use of the same benzimidazole drugs can place selection on the ?-tubulin gene, leading to resistance. Given the concern that resistance could arise in human soil-transmitted helminths, there is an urgent need to develop accurate diagnostic tools for monitoring resistance. In this study, we developed molecular assays to detect putative resistance genetic changes in Ascaris lumbricoides, Trichuris trichiura, and hookworms, and we optimized an egg hatch assay for the canine hookworm Ancylostoma caninum and applied it to Necator americanus. Both assays were tested on field samples. The molecular assays demonstrated their reproducibility and capacity to detect the presence of worms carrying putative resistance-associated genetic changes. However, further investigations are needed to validate our molecular and biological tests on additional field isolates. PMID:23458960

Diawara, Aïssatou; Schwenkenbecher, Jan M; Kaplan, Ray M; Prichard, Roger K

2013-03-04

321

Synthesis and biological activity of radiolabeled phytosterols  

SciTech Connect

/sup 3/H and /sup 14/C-labeled phytosterols were synthesized for the purpose of elucidating insect sterol side-chain dealkylating mechanisms. Sitosterol, stigmasterol, and the 29-fluoro derivatives of these compounds, which are highly toxic, were labeled with /sup 3/H at C-29 in order to study the fate of the two-carbon dealkylation product in vivo and in vitro. The first rapid, reliable in vitro dealkylation bioassay was developed using doubly-labeled (29-/sup 3/H)-(24-/sup 14/C) fucosterol epoxides as the substrates, incubated with midgut preparations from Manduca sexta, the tobacco hornworm. Since C-28 and C-29 are lost in the dealkylation process, the extent of dealkylation is expressed as the change in the isotopic ratio when the system is partitioned between an organic solvent and water after incubation. As predicted, the /sup 3/H//sup 14/C ratio decreases in the organic layer as a function of time, due to loss of /sup 3/H into the aqueous phase as acetate or a biological equivalent. This ratio likewise increases in the aqueous phase for the same reason. The (29-/sup 3/H) phytosterols alone are reliable substrates for the first rapid in vivo bioassay of phytosterol dealkylation.

De Palma, A.

1984-01-01

322

The elmiric acids: biologically active anandamide analogs  

PubMed Central

Summary As chemical entities, lipoamino acids have been known for some time. However, more recently their occurrence and importance in mammalian species has been discovered. They appear to have close relationships with the endocannabinoids not only structurally but also in terms of biological actions. The latter include analgesia, anti-inflammatory effects, inhibition of cell proliferation and calcium ion mobilization. To date about 40 naturally occurring members of this family have been identified and, additionally, several synthetic analogs have been prepared and studied. To facilitate their identity, a nomenclature system has been suggested based on the name elmiric acid (EMA). The prototypic example, N-arachidonoyl glycine does not bind to CB1, however it does inhibit the glycine transporter GLYT2a and also appears to be a ligand for the orphan G-protein-coupled receptor GPR18. It may also have a role in regulating tissue levels of anandamide by virtue of its inhibitory effect on FAAH the enzyme that mediates inactivation of anandamide. Its concentration in rat brain is several fold higher than anandamide supporting its possible role as a physiological mediator. Future studies should be aimed at elucidating the actions of all of the members of this interesting family of molecules.

Burstein, Sumner

2008-01-01

323

Biologically active secondary metabolites from Asphodelus microcarpus.  

PubMed

Bioassay guided fractionation of the ethanolic extract of Asphodelus microcarpus Salzm.et Vivi (Asphodelaceae) resulted in the isolation of one new metabolite, 1,6-dimethoxy-3-methyl-2-naphthoic acid (1) as well as nine known compounds: asphodelin (2), chrysophanol (3), 8-methoxychrysophanol (4), emodin (5), 2-acetyl-1,8-dimethoxy-3-methylnaphthalene (6), 10-(chrysophanol-7'-yl)-10-hydroxychrysophanol-9-anthrone (7), aloesaponol-III-8-methyl ether (8), ramosin (9) and aestivin (10). The compounds were identified by 1D and 2D NMR and HRESIMS. Compounds 3, 6 and 10 were isolated for the first time from this species. Compounds 3 and 4 showed moderate to weak antileishmanial activity with IC50 values of 14.3 and 35.1 microg/mL, respectively. Compound 4 exhibited moderate antifungal activity against Cryptococcus neoformans with an IC50 value of 15.0 microg/mL, while compounds 5, 7 and 10 showed good to potent activity against methicillin resistant Staphylococcus aureus (MRSA) with IC50 values of 6.6, 9.4 microg/mL and 1.4 microg/mL respectively. Compounds 5, 8 and 9 displayed good activity against S. aureus with IC50 values of 3.2, 7.3 and 8.5 microg/mL, respectively. Compounds 7 and 9 exhibited a potent cytotoxic activity against leukemia LH60 and K562 cell lines. Compound 10 showed potent antimalarial activities against both chloroquine-sensitive and chloroquine-resistant strains of Plasmodium falciparum with IC50 values in the range of 0.8-0.7 microg/mL without showing any cytotoxicity to mammalian cells. PMID:24079182

Ghoneim, Mohammed M; Ma, Guoyi; El-Hela, Atef A; Mohammad, Abd-Elsalam I; Kottob, Saeid; El-Ghaly, Sayed; Cutler, Stephen J; Ross, Samir A

2013-08-01

324

Synthesis and biological activity of olomoucine II.  

PubMed

Based on our previous experiences with synthesis of purines, novel 2,6,9-trisubstituted purine derivatives were prepared and assayed for the ability to inhibit CDK1/cyclin B kinase. One of newly synthesized compounds designated as olomoucine II, 6-[(2-hydroxybenzyl)amino]-2-[[1-(hydroxymethyl)propyl]amino]-9-isopropylpurine, displays 10 times higher inhibitory activity than roscovitine, potent and specific CDK1 inhibitor. Olomoucine II in vitro cytotoxic activity exceeds purvalanol A, the most potent CDK inhibitor, as it kills the CEM cells with IC(50) value of 3.0 microM. PMID:12392733

Krystof, Vladimír; Lenobel, René; Havlícek, Libor; Kuzma, Marek; Strnad, Miroslav

2002-11-18

325

Raman Optical Activity of Biological Molecules  

NASA Astrophysics Data System (ADS)

Now an incisive probe of biomolecular structure, Raman optical activity (ROA) measures a small difference in Raman scattering from chiral molecules in right- and left-circularly polarized light. As ROA spectra measure vibrational optical activity, they contain highly informative band structures sensitive to the secondary and tertiary structures of proteins, nucleic acids, viruses and carbohydrates as well as the absolute configurations of small molecules. In this review we present a survey of recent studies on biomolecular structure and dynamics using ROA and also a discussion of future applications of this powerful new technique in biomedical research.

Blanch, Ewan W.; Barron, Laurence D.

326

Modeling in situ soil enzyme activity using continuous field soil moisture and temperature data  

NASA Astrophysics Data System (ADS)

Moisture and temperature are key drivers of soil organic matter decomposition, but there is little consensus on how climate change will affect the degradation of specific soil compounds under field conditions. Soil enzyme activities are a useful metric of soil community microbial function because they are they are the direct agents of decomposition for specific substrates in soil. However, current standard enzyme assays are conducted under optimized conditions in the laboratory and do not accurately reflect in situ enzyme activity, where diffusion and substrate availability may limit reaction rates. The Arrhenius equation, k= A*e(-Ea/RT), can be used to predict enzyme activity (k), collision frequency (A) or activation energy (Ea), but is difficult to parameterize when activities are measured under artificial conditions without diffusion or substrate limitation. We developed a modifed equation to estimate collision frequency and activation energy based on soil moisture to model in-situ enzyme activites. Our model was parameterized using data we collected from the Boston Area Climate Experiment (BACE) in Massachusetts; a multi-factor climate change experiment that provides an opportunity to assess how changes in moisture availability and temperature may impact enzyme activity. Soils were collected from three precipitation treatments and four temperature treatments arranged in a full-factorial design at the BACE site in June 2008, August 2008, January 2009 and June 2009. Enzyme assays were performed at four temperatures (4, 15, 25 and 35°C) to calculate temperature sensitivity and activation energy over the different treatments and seasons. Enzymes activities were measured for six common enzymes involved in carbon (?-glucosidase, cellobiohydrolase, xylosidase), phosphorus (phosphatase) and nitrogen cycling (N-acetyl glucosaminidase, and leucine amino peptidase). Potential enzyme activity was not significantly affected by precipitation, warming or the interaction of the field treatments at any of the dates, however season explained the majority of the variance in enzyme activity for cellobiohydrolase, xylosidase, N-acetyl glucosaminidase and leucine amino peptidase (p<0.01). Changes in seasonal climate appear to have a large effect on enzyme potentials and are likely masking any treatment effects. To model in-situ enzyme activities over the course of a year, daily measurements collected on soil moisture and temperature were used to estimate the collision frequency and activation energy. Our results suggest that collision frequency is largely affected by soil moisture and activation energy affected by soil temperature. Thus, soil enzyme activities are controlled not only by the size of the enzyme pool, but are also strongly affected by temperature and by moisture. Currently, there are no suitable technologies to measure in-situ activities in real-time, but we can make progress in understanding the ecology of enzymes through the combination of lab assays, field sensors, and modeling.

Steinweg, J. M.; Wallenstein, M. D.

2010-12-01

327

Biological Soil Crusts Influence Hydrologic Function Differently in Various Deserts And Future Climate and Land Use will Affect These Relationships  

NASA Astrophysics Data System (ADS)

Biological soil crusts (biocrusts) can completely cover plant interspaces in dryland regions, and can constitute 70% or more of the living ground cover. In these areas, where precipitation is low and soils have low fertility, native plants often rely on intact biological soil crusts to provide water and nutrient flow to the broadly scattered vegetation. In cool desert systems, well-developed biocrusts (dominated by lichens and mosses) roughen the soil surface, increasing residence time of surface water flow. This results in increased and relatively homogenous infiltration of water into the soils. Filaments associated with cyanobacteria, fungi, mosses and lichens increase aggregate formation and stabilize soils, thus reducing sediment production, with well-developed biocrusts conferring much more stability on soils than less developed cyanobacterial dominated biocrusts. In hot and hyper-arid desert systems, biocrusts are generally less developed and dominated by cyanobacteria. These biocrusts generally increase runoff from plant interspaces to downslope vegetation. While reduced infiltration may seem to be negative, it can actually be advantageous to the downslope plants, as they may require small watersheds above them to provide the needed amount of water and nutrients required for their growth. Thus, infiltration and nutrient additions are more heterogenous than in cool desert systems. Soil surface disturbance and climate change have the potential to dramatically alter the species composition and thereby function of biological soil crusts in different deserts. Compressional disturbances results in reduced cover and a loss of lichen and moss species. Changes in climate regimes, such as an increase in temperature or a shift in the amount, timing, or intensity of rainfall, will influence the composition and physiological functioning of biological soil crusts, as various crust components have different photosynthetic and respiration responses to temperature and moisture. Changes in the flora will lead to changes in hydrologic functioning. This, in turn, can have regional, national, and global implications.

Belnap, J.; Wilcox, B.; Barger, N.; Herrick, J.; van Soyoc, M.

2012-04-01

328

Glutathione conjugation attenuates biological activities of 6-dehydroshogaol from ginger.  

PubMed

6-Dehydroshogaol (6-DHSG) is a bioactive ?,?-unsaturated carbonyl compound isolated from fresh ginger with anti-inflammatory and phase II enzyme inducing activities. Here we describe the glutathione (GSH)-dependent metabolism and the effect of this metabolic transformation on the biological activities of 6-DHSG. Compared with other ginger compounds, such as 6-gingerol and 6-shogaol, 6-DHSG showed the most potent anti-inflammatory effect in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. The biological activities of 6-DHSG were attenuated by sulfhydryl antioxidants such as glutathione (GSH) or N-acetyl cysteine (NAC), but not ascorbic acid (ASC). 6-DHSG was metabolised by GSH to form a GSH conjugate (GS-6-DHSG) in RAW 264.7 cells, via a potential mechanism involving the catalytic activity of glutathione-S-transferase (GST). GS-6-DHSG showed reduced biological activities compared with 6-DHSG in multiple biological assays. Together, these results indicate that GSH conjugation attenuates the biological activities of 6-DHSG and other ?,?-unsaturated carbonyl compounds. PMID:23578607

Zhang, Guodong; Nitteranon, Viriya; Chan, Lok Yan; Parkin, Kirk L

2013-02-26

329

NEW AMINOPHOSPHONATES - ASSESSMENT OF BIOLOGICAL ACTIVITY  

Microsoft Academic Search

Two series, acyclic and cyclic aminophosphonates were synthesized for potential agrochemical application. They differed inside the series in substituents at the phosphorus, carbon and nitrogen atoms. Their efficiency to destabilize erythrocyte (RBC) and lipid model membranes (BLM), to change plant membrane properties (Nitellopsis obtusa, Beta vulgaris ssp. L. rapacea, Syringa vulgaris L., Cucumis sativus), to change activity of the antioxidative

2009-01-01

330

Biological Activity of 25-Hydroxyergocalciferol in Rats  

Microsoft Academic Search

Hydroxyergocalciferol is 1.5 times more effective than either vitamin D2 or Da in curing rickets in rats (60 units antirachilie activity per microgram). It is effective in inducing intestinal calcium transport and mobilization of bone mineral in rats and acts much more rapidly in these two systems than does vitamin D2.

T. SUDA; H. F. DELUCA

331

Field Trial Assessment of Biological, Chemical, and Physical Responses of Soil to Tillage Intensity, Fertilization, and Grazing  

NASA Astrophysics Data System (ADS)

Soil microbial populations can fluctuate in response to environmental changes and, therefore, are often used as biological indicators of soil quality. Soil chemical and physical parameters can also be used as indicators because they can vary in response to different management strategies. A long-term field trial was conducted to study the effects of different tillage systems (NT: no tillage, DH: disc harrow, and MP: moldboard plough), P fertilization (diammonium phosphate), and cattle grazing (in terms of crop residue consumption) in maize ( Zea mays L.), sunflower ( Heliantus annuus L.), and soybean ( Glycine max L.) on soil biological, chemical, and physical parameters. The field trial was conducted for four crop years (2000/2001, 2001/2002, 2002/2003, and 2003/2004). Soil populations of Actinomycetes, Trichoderma spp., and Gliocladium spp. were 49% higher under conservation tillage systems, in soil amended with diammonium phosphate (DAP) and not previously grazed. Management practices also influenced soil chemical parameters, especially organic matter content and total N, which were 10% and 55% higher under NT than under MP. Aggregate stability was 61% higher in NT than in MP, 15% higher in P-fertilized soil, and also 9% higher in not grazed strips, bulk density being 12% lower in NT systems compared with MP. DAP application and the absence of grazing also reduced bulk density (3%). Using conservation tillage systems, fertilizing crops with DAP, and avoiding grazing contribute to soil health preservation and enhanced crop production.

Vargas Gil, Silvina; Becker, Analia; Oddino, Claudio; Zuza, Mónica; Marinelli, Adriana; March, Guillermo

2009-08-01

332

Biological and chemical properties of arable soils affected by long-term organic and inorganic fertilizer applications  

Microsoft Academic Search

Using soils from field plots in four different arable crop experiments that have received combinations of manure, lime and\\u000a inorganic N, P and K for up to 20?years, the effects of these fertilizers on soil chemical properties and estimates of soil\\u000a microbial community size and activity were studied. The soil pH was increased or unaffected by the addition of organic

M. Šimek; D. W. Hopkins; J. Kal?ík; T. Picek; H. Šantr??ková; J. Sta?a; K. Trávník

1999-01-01

333

Biological activities of terthiophenes and polyynes from the Asteraceae.  

PubMed

We evaluated a number of terthiophenes and polyynes, from the Asteraceae, for biological activities against microorganisms, viruses, and tumor cells, with and without the aid of UVA (long wavelength ultraviolet) radiation. The terthiophenes, which represented the basic alpha-terthienyl nucleus with simple side chains, showed impressive UVA-dependent activities, some of which were superior to alpha-terthienyl itself. In contrast, the polyynes had no significant biological activity, with or without UVA. We believe that these terthiophenes would be worthwhile evaluating in animal models of infectious diseases. PMID:8255937

Hudson, J B; Graham, E A; Rossi, R; Carpita, A; Neri, D; Towers, G H

1993-10-01

334

Transport of biologically active material in laser cutting.  

PubMed

The transport of biologically active material during laser cutting with CO2 and Er lasers is demonstrated. This transport mechanism removes particles from the surface of gelatin, agar, and liver samples into the depth of the laser-formed craters. The transport phenomenon is explained by a contraction and condensation of enclosed hot water vapor. We show by cultivating transported bacteria in agar that biological particles can survive the shock of the transport. Determination of the numbers of active cells evidences a more pronounced activity of the cultivated bacteria after impact with an Er laser than with a CO2 laser. PMID:3062290

Frenz, M; Mathezloic, F; Stoffel, M H; Zweig, A D; Romano, V; Weber, H P

1988-01-01

335

Liposomal Packaging Generates Wnt Protein with In Vivo Biological Activity  

PubMed Central

Wnt signals exercise strong cell-biological and regenerative effects of considerable therapeutic value. There are, however, no specific Wnt agonists and no method for in vivo delivery of purified Wnt proteins. Wnts contain lipid adducts that are required for activity and we exploited this lipophilicity by packaging purified Wnt3a protein into lipid vesicles. Rather than being encapsulated, Wnts are tethered to the liposomal surface, where they enhance and sustain Wnt signaling in vitro. Molecules that effectively antagonize soluble Wnt3a protein but are ineffective against the Wnt3a signal presented by a cell in a paracrine or autocrine manner are also unable to block liposomal Wnt3a activity, suggesting that liposomal packaging mimics the biological state of active Wnts. When delivered subcutaneously, Wnt3a liposomes induce hair follicle neogenesis, demonstrating their robust biological activity in a regenerative context.

Zhao, Ludan; Kim, Jae-Beom; ten Berge, Derk; Ponnusamy, Karthik; Carre, A. Lyonel; Dudek, Henryk; Zachlederova, Marie; McElhaney, Michael; Brunton, Shirley; Gunzner, Janet; Callow, Marinella; Polakis, Paul; Costa, Mike; Zhang, Xiaoyan M.; Helms, Jill A.; Nusse, Roel

2008-01-01

336

Influence of biological soil crusts at different successional stages in the implantation of biogeochemical cycles in arid and semiarid zones  

NASA Astrophysics Data System (ADS)

Influence of biological soil crusts at different successional stages in the implantation of biogeochemical cycles in arid and semiarid zones I. Miralles1, F. Gil-Sotres2, Y. Cantón-Castilla3, F. Domingo1, M.C. Leirós2, C. Trasar-Cepeda4 1 Experimental Estation of Arid Zones (CSIC), E-04230 La Cañada de San Urbano, Almería, Spain. 2 Departamento Edafología y Química Agrícola, Grupo de Evaluación de la Calidad del Suelo, Unidad Asociada CSIC, Facultad de Farmacia, Universidad de Santiago de Compostela, E-15782 Santiago de Compostela, Spain. 3 University of Almería, Departamento de Edafología y Química Agrícola, E-04230-La Cañada de San Urbano, Almería, Spain. 4 Departamento Bioquímica del Suelo, IIAG-CSIC, Apartado 122, E-15708 Santiago de Compostela, Spain. Crusts (BSCs) are formed by a close association between soil particles and cyanobacteria, algae, lichens, bryophytes and microfungi in varying proportions. Their habitat is within or immediately on top of the uppermost millimetres of the soil and are the predominant surface cover in arid and semiarid zones. Among the diverse functions developed by BSCs in the ecosystem (hydrology, erosion, soil properties, etc.), one of the most important is its role in nutrient cycling. Within arid and semiarid environments, BSCs have been termed 'mantles of fertility' being considered hotspots of biogeochemical inputs, fixing C, N and P above- and below-ground. However, there are differences in N and C fixation rates between BSCs types. Early successional BSCs, dominated by cyanobacterial species, fix lower quantities of C and N than mature BSCs dominated by lichens. Although the positive effects of BSCs on biogeochemical soil cycles are widely accepted, no previous studies have evaluated the activities of the enzymes involved in C, N and P cycles of BSCs and how they are affected by the successional stage of the BSC. In this work, performed in the Tabernas desert (SE Spain), we studied the hydrolase enzymes involved in C (invertase, CM-cellulase, ?-glucosidase), N (urease, BAA-protease, casein-protease) and P (phosphomonoesterase) cycles in BSCs at different successional stages (cyanobacteria represents the first successional stage, lichen Diploschistes diacapsis in an intermediate state and lichen Lepraria crassissima, with the greatest successional state). Our results show that BSCs at lower successional stage enriched the surface geological substrate in hydrolase enzymes to a lesser extent than mature BSCs (Lepraria crassissima), which show the highest values in all enzymatic activities. In contrast, the specific enzyme activities (activity values expressed per unit of carbon) were higher in the BSCs at lower successional stage, decreasing in the direction: cyanobacteria > Diploschistes diacapsis-lichen > Lepraria crassissima-lichen. These results suggest a different role of BSCs depending on their successional stage with regard to the implantation of biogeochemical cycles during the surface substrate colonization. Our conclusions are highly relevant to improve the knowledge of biogeochemical cycles in arid and semiarid areas. Keywords: Biological Soil Crusts, arid ecosystems, hydrolytic enzymes, biochemical activity

Gil-Sotres, F.; Miralles, I.; Canton-Castilla, Y.; Domingo, F.; Leiros, M. C.; Trasar-Cepeda, C.

2012-04-01

337

Biological Activity of Grapevine Phenolic Compounds  

Microsoft Academic Search

Phenolic compounds present in nearly all parts of grape berries are increasingly believed to exhibit antioxidant and antimicrobial\\u000a activities and to play a significant role in the prevention of diseases including cancer and cardiovascular diseases (Bagchi\\u000a et al. 2000, Ariga 2004). The majority of studies on grape phenolics properties has been conducted using proanthocyanidin-rich\\u000a seeds extracts (GSEs).

R. Amarowicz; S. Weidner

338

Biologically active constituents of Aglaia erythrosperma.  

PubMed

From the fruits and leaves of Aglaia erythrosperma (Meliaceae), 10 chemical constituents were isolated and identified, i.e. the dammarane triterpenoids cabraleadiol (1), cabraleahydroxylactone (2), ethyl eichlerianoate (3), eichlerialactone (4), aglinin A (5), cabralealactone (6), the aglaialactone 5,6-desmethylenedioxy-5-methoxy-aglalactone (7), the flavagline 4'-demethoxy-3',4'-methylenedioxy-methyl rocaglate (8) and two coumarins: scoparone and scopoletin. Flavagline 8 exhibited antimalarial activity with an IC(50) value of 7.30 µg mL(-1) and was strongly cytotoxic against small cell lung cancer (NCI-H187), epidermoid carcinoma (KB) and breast cancer (BC) cell lines, with IC(50) values of 2.17, 2.10 and 0.11 µg mL(-1), respectively. Aglinin A (5) displayed moderate cytotoxicity against all the three cancer cell lines, whereas ethyl eichlerianoate (3), cabralealactone (6) and the aglaialactone 7 were exclusively cytotoxic to NCI-H187 cell line. Cabraleahydroxylactone (2) showed antiviral activity against herpes simplex virus type-1 with an IC(50) value of 3.20 µg mL(-1), in comparison with the standard acyclovir (IC(50)?= 1.90 µg mL(-1)). When tested for antimycobacterial activity against Mycobacterium tuberculosis H(37)Ra, compounds 1-4 and 6-8 displayed minimum inhibitory concentration in the range of 25-50 µg mL(-1). PMID:22011221

Phongmaykin, Jarinporn; Kumamoto, Takuya; Ishikawa, Tsutomu; Saifah, Ekarin; Suttisri, Rutt

2011-06-16

339

Diazotrophic Community Structure and Function in Two Successional Stages of Biological Soil Crusts from the Colorado Plateau and Chihuahuan Desert  

USGS Publications Warehouse

The objective of this study was to characterize the community structure and activity of N2-fixing microorganisms in mature and poorly developed biological soil crusts from both the Colorado Plateau and Chihuahuan Desert. Nitrogenase activity was approximately 10 and 2.5 times higher in mature crusts than in poorly developed crusts at the Colorado Plateau site and Chihuahuan Desert site, respectively. Analysis of nifH sequences by clone sequencing and the terminal restriction fragment length polymorphism technique indicated that the crust diazotrophic community was 80 to 90% heterocystous cyanobacteria most closely related to Nostoc spp. and that the composition of N2-fixing species did not vary significantly between the poorly developed and mature crusts at either site. In contrast, the abundance of nifH sequences was approximately 7.5 times greater (per microgram of total DNA) in mature crusts than in poorly developed crusts at a given site as measured by quantitative PCR. 16S rRNA gene clone sequencing and microscopic analysis of the cyanobacterial community within both crust types demonstrated a transition from a Microcoleus vaginatus-dominated, poorly developed crust to mature crusts harboring a greater percentage of Nostoc and Scytonema spp. We hypothesize that ecological factors, such as soil instability and water stress, may constrain the growth of N2-fixing microorganisms at our study sites and that the transition to a mature, nitrogen-producing crust initially requires bioengineering of the surface microenvironment by Microcoleus vaginatus.

Yeager, C. M.; Kornosky, J. L.; Housman, D. C.; Grote, E. E.; Belnap, J.; Kuske, C. R.

2004-01-01

340

Evaluation of the biological control potential of bacteria isolated from a soil suppressive to Phytophthora cinnamomi  

Microsoft Academic Search

Roots from 15-year-old avocado trees growing in a soil suppressive to Phytophthora cinnamomi were collected from Maleny, Queensland. Of 164 bacteria isolated from the rhizosphere, three fluorescent pseudomonads, nine\\u000a actinomycetes and a Serratia sp. showed in vitro antagonistic activity against P. cinnamomi. The fluorescent pseudomonads also showed in vitro antifungal activity against a wide range of other fungi. When selected

A. M. Stirling; A. C. Hayward; K. G. Pegg

1992-01-01

341

Temperature sensitivity of microbial respiration, nitrogen mineralization, and potential soil enzyme activities in organic alpine soils  

NASA Astrophysics Data System (ADS)

Investigations focusing on the temperature sensitivity of microbial activity and nutrient turnover in soils improve our understanding of potential effects of global warming. This study investigates the temperature sensitivity of C mineralization, N mineralization, and potential enzyme activities involved in the C and N cycle (tyrosine amino-peptidase, leucine amino-peptidase, ß-glucosidase, ß-xylosidase, N-acetyl-ß-glucosaminidase). Four different study sites in the Austrian alpine zone were selected, and soils were sampled in three seasons (summer, autumn, and winter). A simple first-order exponential equation was used to calculate constant Q10 values for the C and N mineralization over the investigated temperature range (0-30°C). The Q10 values of the C mineralization (average 2.0) for all study sites were significantly higher than for the N mineralization (average 1.7). The Q10 values of both activities were significantly negatively related to a soil organic matter quality index calculated by the ratios of respiration to the organic soil carbon and mineralized N to the total soil nitrogen. The chemical soil properties or microbial biomass did not affect the Q10 values of C and N mineralization. Moreover, the Q10 values showed no distinct pattern according to sampling date, indicating that the substrate quality and other factors are more important. Using a flexible model function, the analysis of relative temperature sensitivity (RTS) showed that the temperature sensitivity of activities increased with decreasing temperature. The C and N mineralization and potential amino-peptidase activities (tyrosine and leucine) showed an almost constant temperature dependence over 0-30°C. In contrast, ß-glucosidase, ß-xylosidase, and N-acetyl-ß-glucosaminidase showed a distinctive increase in temperature sensitivity with decreasing temperature. Low temperature at the winter sampling date caused a greater increase in the RTS of all microbial activities than for the autumn and summer sampling dates. Our results indicate (1) a disproportion of the RTS for potential enzyme activities of the C and N cycle and (2) a disproportion of the RTS for easily degradable C compounds (ß-glucose, ß-xylose) compared with the C mineralization of soil organic matter. Thus temperature may play an important role in regulating the decay of different soil organic matter fractions due to differences in the relative temperature sensitivities of enzyme activities.

Koch, Oliver; Tscherko, Dagmar; Kandeler, Ellen

2007-12-01

342

Synthesis and biological activity of 5-fluorotubercidin.  

PubMed

The electrophilic fluorination of 4-chloropyrrolo[2,3-d]pyrimidine (1) was studied culminating a 59% conversion of compound 1 to 4-chloro-5-fluoropyrrolo[2,3-d]pyrimidine (2) using Selectfluor. This transformation proceeded via the 4-chloro-5,6-dihydro-5-fluoro-6-hydroxypyrrolo[2,3-d]pyrimidine (3) in a 9:1 trans:cis ratio. The trans isomer of compound 3 was studied by 1H NMR and 19F NMR, and the 5-H tautomer (4) was observed as another intermediate. A modified Vorbruggen procedure of compound 2 and tetra-O-acetylribose gave 4-chloro-5-fluoro-7-(2,3,5,-tri-O-benzoyl-beta-D-ribofuranosyl)pyrrolo[2,3-d]pyrimidine (6) in a 65% yield. Treatment of compound 6 with ammonia (l) in dioxane gave 5-fluorotubercidin (7). No antibacterial activity was observed. An MTT assay (Promega) against Huh-7 liver cells, normal mouse spleen cells stimulated with Con A (a T-cell mitogen), and normal mouse spleen stimulated with LPS (a B-cell mitogen) showed no significant toxicity. Increased activity of 7 over tubercidin was observed against L-1210 cells and toxicity in fibroblast cells was reduced. PMID:15043144

Wang, Xiaojing; Seth, Punit P; Ranken, Ray; Swayze, Eric E; Migawa, Michael T

2004-01-01

343

Spatial structure of microbial biomass and activity in prairie soil ecosystems  

Microsoft Academic Search

Management of soil ecosystems requires assessment of key soil physicochemical and microbial properties and the spatial scale over which they operate. The objectives were to determine the spatial structure of microbial biomass and activity and related soil properties, and to identify spatial relationships of these properties in prairie soils under different management histories. Soil were sampled along a transect at

Eirini Katsalirou; Shiping Deng; David L. Nofziger; Argyrios Gerakis; Samuel D. Fuhlendorf

2010-01-01

344

Multiscale MAS modelling to simulate the soil environment: Application to soil ecology  

Microsoft Academic Search

Soils are important components of ecosystem and their functioning is of great importance for human well-being. Describing, understanding, foreseeing, and controlling biological activities and functions in soil in the context of global change are major objectives for scientists. Modelling soil bioturbation by soil engineers is of great importance although it is faced with the difficulty to describe the soil physical

N. Marilleau; C. Cambier; Alexis Drogoul; J.-L. Chotte; Edith Perrier; E. Blanchart

2008-01-01

345

Soil hydrological and soil property changes resulting from termite activity on agricultural fields in Burkina Faso  

NASA Astrophysics Data System (ADS)

Termites are important ecosystem-engineers in subtropical and tropical regions. The effect of termite activity affecting soil infiltration is well documented in the Sahelian region. Most studies find increased infiltration rates on surfaces that are affected by termite activity in comparison to crusted areas showing non-termite presence. Crusted agricultural fields in the Sanmatenga region in Burkina Faso with clear termite activity were compared to control fields without visual ground dwelling termite activity. Fine scale rainfall simulations were carried out on crusted termite affected and control sites. Furthermore soil moisture change, bulk density, soil organic matter as well as general soil characteristics were studied. The top soils in the study area were strongly crusted (structural crust) after the summer rainfall and harvest of millet. They have a loamy sand texture underlain by a shallow sandy loam Bt horizon. The initial soil moisture conditions were significantly higher on the termite plots when compared to control sites. It was found that the amount of runoff produced on the termite plots was significantly higher, and also the volumetric soil moisture content after the experiments was significantly lower if compared to the control plots. Bulk density showed no difference whereas soil organic matter was significantly higher under termite affected areas, in comparison to the control plots. Lab tests showed no significant difference in hydrophobic behavior of the topsoil and crust material. Micro and macro-structural properties of the topsoil did not differ significantly between the termite sites and the control sites. The texture of the top 5 cm of the soil was also found to be not significantly different. The infiltration results are contradictory to the general literature, which reports increased infiltration rates after prolonged termite activity although mostly under different initial conditions. The number of nest entrances was clearly higher in the termite areas, but apparently did not significantly affect infiltration. The increased soil organic matter contents in the termite affected areas however, are as expected from literature, but did not improve soil aggregation which would be expected given the importance of organic matter in soil aggregation in this type of soils. One of the explanations for the reduced infiltration rates might be that termites bring clay from the finer textured subsoil to the surface to build casts over the organic material on the surface (mainly millet stems). It is speculated that the excavated clay material could be involved in crust formation, only present is in the upper 0.5 cm of the soil crust, which is enough to block pores in the crust surface, hampering infiltration. The topsoil aggregates are slaking under the summer rainfall and the increase in fine textured material, excavated by the termites, could be incorporated into the crust and reduce infiltration. Furthermore this specific effect might also be related to the type of termite involved, as impacts from ecosystem engineers on their environment is highly dependent on the specific species involved.

Mettrop, I.; Cammeraat, L. H.; Verbeeten, E.

2009-04-01

346

[The biological activity of lysosomotropic agents].  

PubMed

Lysosomotropic agents have antitumor, antifungal and antimicrobial properties. These small, amphiphilic compounds, as weak bases, readily penetrate the lipid bilayer and diffuse into acidic subcellular compartments such as lysosomes or vacuoles. The mechanism of action of lysosomotropic compounds can be distinct, depending on their chemical structure and/or the kind of cells influenced. Our investigations of the influence of lysosomotropic agents on Saccharomyces cerevisiae have lead to a partial explanation of their mechanism of action. The amphiphilic character enables the compounds to penetrate the lipid bilayer and disturb its structure and functions and can inhibit the activity of plasma membrane H+ATPase. The accumulation of the compounds in yeast vacuoles, disrupting them and killing yeast cells, is another mechanism of action. Lysosomotropic agents can be substrates for ABC transporters in Saccharomyces cerevisiae cells. PMID:20966503

Ob??k, Ewa; Krasowska, Anna

2010-10-13

347

The biological and toxicological activity of gases and vapors.  

PubMed

A large amount of data on the biological and toxicological activity of gases and vapors has been collected from the literature. Processes include sensory irritation thresholds, the Alarie mouse test, inhalation anesthesia, etc. It is shown that a single equation using only five descriptors (properties of the gases and vapors) plus a set of indicator variables for the given processes can correlate 643 biological and non-lethal toxicological activities of 'non-reactive' compounds with a standard deviation of 0.36 log unit. The equation is scaled to sensory irritation thresholds obtained by the procedure of Cometto-Muñiz, and Cain provides a general equation for the prediction of sensory irritation thresholds in man. It is suggested that differences in biological/toxicological activity arise primarily from transport from the gas phase to a receptor phase or area, except for odor detection thresholds where interaction with a receptor(s) is important. PMID:19913608

Abraham, Michael H; Sánchez-Moreno, Ricardo; Gil-Lostes, Javier; Acree, William E; Cometto-Muñiz, J Enrique; Cain, William S

2009-11-12

348

The Biological and Toxicological Activity of Gases and Vapors  

PubMed Central

A large amount of data on the biological and toxicological activity of gases and vapors has been collected from the literature. Processes include sensory irritation thresholds, the Alarie mouse test, inhalation anesthesia, etc. It is shown that a single equation using only five descriptors (properties of the gases and vapors) plus a set of indicator variables for the given processes can correlate 643 biological and non-lethal toxicological activities of ‘non-reactive’ compounds with a standard deviation of 0.36 log unit. The equation is scaled to sensory irritation thresholds obtained by the procedure of Cometto-Muñiz, and Cain, and provides a general equation for the prediction of sensory irritation thresholds in man. It is suggested that differences in biological/toxicological activity arise primarily from transport from the gas phase to a receptor phase or area, except for odor detection thresholds where interaction with a receptor(s) is important.

Sanchez-Moreno, Ricardo; Gil-Lostes, Javier; Acree, William E.; Cometto-Muniz, J. Enrique; Cain, William S.

2010-01-01

349

Sensitive bioassay for detection of biologically active ricin in food.  

PubMed

The potential use of ricin as an agent of biological warfare highlights the need to develop fast and effective methods to detect biologically active ricin. The current "gold standard" for ricin detection is an in vivo mouse bioassay; however, this method is not practical to test on a large number of samples and raises ethical concerns with regard to the use of experimental animals. In this work, we generated adenoviral vectors that express the green fluorescent protein gene and used the relative fluorescence units intensity inhibition by transduced cells for quantitative measurement of biologically active ricin. The detection limit of the assay was 200 pg/ml, which is over 500,000 times greater than the adult human lethal oral dose. The inhibition of fluorescence intensity between ricin treatment and control was higher in 72-h posttransduction Vero cells than 24-h human embryonic kidney cells. Therefore, to detect biologically active ricin in food matrices that might influence the assay, we used 72-h posttransduction Vero cells. This simple assay could be used for large-scale screening to detect biologically active ricin in food without added substrates or use of cell fixation methods. PMID:22564946

Rasooly, Reuven; He, Xiaohua

2012-05-01

350

Chemical composition and biological activities of Arachis species.  

PubMed

Arachis hypogaea , known as the peanut, is native to South America. Peanut contains several active components including flavonoids, phenolic acids, phytosterols, alkaloids, and stilbenes. Some therapeutic effects have been reported for peanut seed extracts, such as antioxidative, antibacterial, antifungal, and anti-inflammatory activities. This paper aims to give an overview of the chemical composition, focusing on secondary metabolites, and of the biological activity of A. hypogaea, to stimulate new studies about species of the Arachis genus. PMID:21425852

Lopes, Renata Miranda; Agostini-Costa, Tânia da Silveira; Gimenes, Marcos Aparecido; Silveira, Dâmaris

2011-04-14

351

Biological and pharmacological activity of naturally occurring iridoids and secoiridoids.  

PubMed

The biological and pharmacological activities reported for naturally occurring iridoids and secoiridoids are reviewed. The hypothesis that iridoid glycoside and acetal esters can best be considered as pro-drugs and that corresponding hemiacetals and compounds derived from them carry the pharmacophores is discussed. The possibility that the activity of some iridoids is determined by their conversion to pyridine monoterpene alkaloids (PMTA) is also considered. The evidence available suggests that iridoids show activities consistent with those presented by immunomodulators and adaptogens. PMID:23195768

Ghisalberti, E L

1998-04-01

352

[Oregano: properties, composition and biological activity].  

PubMed

The oregano spice includes various plant species. The most common are the genus Origanum, native of Europe, and the Lippia, native of Mexico. Among the species of Origanum. their most important components are the limonene, gamma-cariofilene, rho-cymenene, canfor, linalol, alpha-pinene, carvacrol and thymol. In the genus Lippia, the same compounds can be found. The oregano composition depends on the specie, climate, altitude, time of recollection and the stage of growth. Some of the properties of this plant's extracts are being currently studied due to the growing interest for substituting synthetic additives commonly found in foods. Oregano has a good antioxidant capacity and also presents antimicrobial activity against pathogenic microorganisms like Salmonella typhimurium, Escherichia coli, Staphylococcus aureus, Staphylococcus epidermidis, among others. These are all characteristics of interest for the food industry because they may enhance the safety and stability of foods. There are also some reports regarding the antimutagenic and anticarcinogenic effect of oregano; representing an alternative for the potential treatment and/or prevention of certain chronic ailments, like cancer. PMID:15332363

Arcila-Lozano, Cynthia Cristina; Loarca-Piña, Guadalupe; Lecona-Uribe, Salvador; González de Mejía, Elvira

2004-03-01

353

Azaglycomimetics: Natural Occurrence, Biological Activity, and Application  

NASA Astrophysics Data System (ADS)

A large number of alkaloids mimicking the structures of monosaccharides or oligosaccharides have been isolated from plants and microorganisms. The sugar mimicking alkaloids with a nitrogen in the ring are called azasugars or iminosugars. Naturally occurring azasugars are classified into five structural classes: polyhydroxylated piperidines, pyrrolidines, indolizidines, pyrrolizidines, and nortropanes. They are easily soluble in water because of their polyhydroxylated structures and inhibit glycosidases because of a structural resemblance to the sugar moiety of the natural substrate. Glycosidases are involved in a wide range of anabolic and catabolic processes, such as digestion, lysosomal catabolism of glycoconjugates, biosynthesis of glycoproteins, and the endoplasmic reticulum (ER) quality control and ER-associated degradation of glycoproteins. Hence, modifying or blocking these processes in vivo by inhibitors is of great interest from a therapeutic point of view. Azasugars are an important class of glycosidase inhibitors and are arousing great interest for instance as antidiabetics, antiobesity drugs, antivirals, and therapeutic agents for some genetic disorders. This review describes the recent studies on isolation, characterization, glycosidase inhibitory activity, and therapeutic application of azaglycomimetics.

Asano, Naoki

354

Active microcantilever device for biological agent detection  

NASA Astrophysics Data System (ADS)

The measurement of binding forces between specific antigen-antibody pairs presents a powerful tool for sensitive detection with applications in medical diagnostics, bioagent sensing, and environmental monitoring. The ability to detect single molecular binding events with an AFM, using the technique of dynamic force spectroscopy, is a known capability; however, reliance on traditional AFM architectures limits the use of this method to laboratory environments. The approach presented here uses active piezoelectric microcantilevers, providing electronic output for detection of molecular binding. Functionalization of this device with specific antibodies provides a platform for a stand-alone detection device. As the microcantilever can be operated as both a sensor and an actuator, the detection scheme includes actuating the cantilever to present an antibody bound to the cantilever tip to a second antibody bound to a fixed substrate. If a target antigen is present in solution, the cantilever detects the mechanical strain and vibrational response created by the binding force and subsequent rupture of the antigen-antibody pair. This detection strategy distinguishes this work from resonance-based cantilever devices that respond to changes in cantilever mass based on adsorption of numerous antigen molecules. In this research, piezoelectric microcantilevers were fabricated, and initial results were obtained demonstrating transient response caused by rupture of nonspecific adhesion forces in air and water environments. Analytical results are also presented relating geometrical parameters with sensor performance.

Dausch, David E.; Gilchrist, Kristin H.; Cole, Daniel G.; Rivera, Monica; Clark, Robert L.

2006-06-01

355

Teaching Systems Biology: An Active-learning Approach  

PubMed Central

With genomics well established in modern molecular biology, recent studies have sought to further the discipline by integrating complementary methodologies into a holistic depiction of the molecular mechanisms underpinning cell function. This genomic subdiscipline, loosely termed “systems biology,” presents the biology educator with both opportunities and obstacles: The benefit of exposing students to this cutting-edge scientific methodology is manifest, yet how does one convey the breadth and advantage of systems biology while still engaging the student? Here, I describe an active-learning approach to the presentation of systems biology. In graduate classes at the University of Michigan, Ann Arbor, I divided students into small groups and asked each group to interpret a sample data set (e.g., microarray data, two-hybrid data, homology-search results) describing a hypothetical signaling pathway. Mimicking realistic experimental results, each data set revealed a portion of this pathway; however, students were only able to reconstruct the full pathway by integrating all data sets, thereby exemplifying the utility in a systems biology approach. Student response to this cooperative exercise was extremely positive. In total, this approach provides an effective introduction to systems biology appropriate for students at both the undergraduate and graduate levels.

2005-01-01

356

[Biological activity of Penicillium sp. 10-51 exometabolites].  

PubMed

Silica gel column chromatography (silica gel "L" II kind of activity 100/160 mkm) of the chloroform extract from the cultural filtrate of Penicillium sp. 10-51 gave two fractions (chloroform and chloroform-acetone, 5:1) having biological activity. Recrystallization yielded two compounds. On the basis of physico-chemical and spectral data these compounds were identified as curvularin and hydroxycurvularin, which have a large spectrum of biological action as to bacteria, yeast, blue-green algae and phytopathogenic micromycetes. PMID:23088100

Savchuk, Ia I; Za?chenko, A M; Tsyganenko, E S

357

Biological Activity of Aminophosphonic Acids and Their Short Peptides  

NASA Astrophysics Data System (ADS)

The biological activity and natural occurrence of the aminophosphonic acids were described half a century ago. Since then the chemistry and biology of this class of compounds have developed into the separate field of phosphorus chemistry. Today it is well acknowledged that these compounds possess a wide variety of promising, and in some cases commercially useful, physiological activities. Thus, they have found applications ranging from agrochemical (with the herbicides glyphosate and bialaphos being the most prominent examples) to medicinal (with the potent antihypertensive fosinopril and antiosteoporetic bisphosphonates being examples).

Lejczak, Barbara; Kafarski, Pawel

358

Functional toxicology: a new approach to detect biologically active xenobiotics.  

PubMed Central

The pervasiveness of chemicals in the environment with estrogenic activity and other biological functions recommends the development of new approaches to monitor and study them. Chemicals can be screened for activity in vitro using a panel of human or animal cells that have been transfected with a specific receptor and reporter gene; for example, the estrogen receptor. By using a variety of different receptors, the screening of xenobiotics for biological functions can be broad. Chemicals could then be classified by their function in vitro which, in some cases, may be a useful guide for toxicological studies. Images Figure 1.

McLachlan, J A

1993-01-01

359

Studies on Speciation of Antimony in Soil Contaminated by Industrial Activity  

Microsoft Academic Search

Antimony is a toxic trace element of growing environmental interest due to its increased anthropogenic input into the environment. Very little is known about the chemical and biological behavior of antimony compounds in soils and sediments. Three soil samples with substantially elevated Sb concentrations (area contaminated by extensive industrial use of Sb compounds), and a soil standard reference material have

Joseph Lintschinger; Bernhard Michalke; Sigurd Schulte-hostede; Peter Schramel

1998-01-01

360

Mobility and microbial activity of allelochemicals in soil.  

PubMed

The action of allelochemicals in soil needs their presence in the vicinity of the target plants. Using a soil TLC combined with bioassay approach, the mobility of 10 typical allelochemicals was evaluated. Ferulic, p-hydroxymandelic, p-hydroxybenzoic, and vanillic acids always had the lowest mobility (Rf < 0.1), whereas phenolic aldehyde and lactone (vanillin and coumarin) showed the highest mobility (Rf > 0.5). The Rf values of daidzein, 1?-angeloyloxycarotol, DIMBOA, and m-tyrosine ranged from 0.24 to 0.32. Binary mixtures of these allelochemicals led to an increase in mobility factors for selected combinations. Phospholipid fatty acid profiling indicated that there were different soil microbial communities in the segments containing allelochemicals residues in the developed TLC soil layer. A difference in microbial community structure occurred between two nitrogenous DIMBOA and m-tyrosine and another eight allelochemicals. The results suggest that the soil activity of allelochemicals on bioassay species and microbial communities depends on their mobility in soil. PMID:23647315

Li, Xiao-Jing; Xia, Zhi-Chao; Kong, Chui-Hua; Xu, Xiao-Hua

2013-05-16

361

Non-biological fixation of atmospheric nitrogen to nitrate on titanium dioxide and desert soil surfaces  

NASA Astrophysics Data System (ADS)

Elevated nitrate levels have frequently been observed in soils and the associated groundwater in arid regions of the U.S, many of which are distant from anthropogenic sources. Although these elevated nitrate concentrations have generally been linked to atmospheric precipitation, the current study indicates that at least a portion of these nitrates may have been formed through photochemical and thermal transformation reactions on soil surfaces. Photochemical nitrogen fixation to nitrate was observed on pure TiO 2 (both anatase and rutile) and desert soil surfaces when exposed to sunlight from 2 to 80 days. The yields of nitrate were generally proportional to irradiation time and increased substantially when sodium hydroxide was added. Larger surface films of soils or TiO2 generated higher yields of nitrate. Soils with higher content of both titanium and calcium exhibit higher photoactivities, and the production rate varied slightly with particle size. Traces of nitrite and ammonia detected on irradiated TiO2 surface were similar to background levels, and are probably not intermediates in the formation of nitrate. TiO2 and soils obtained from Atacama Desert in northern Chile and Pyramid Lake, NV were irradiated with sunlight for 32 days in either 15N labeled or unlabeled nitrogen and produced nitrates enriched in 15N and that nearly all isotopic values were higher than that of atmospheric 15N. Nitrate produced photochemically on Atacama Desert soils have isotopic values that are similar to those of the subsoil nitrates of the Atacama Desert. During our experimental investigation and while preparing thin films of TiO2 by thermal evaporation of an aqueous suspension in Petri dishes, we consistently observed an increase in nitrate concentrations in all samples (even the controls) whenever TiO2 slurries came in contact with heat and air. An expanded series of experiments was carried out in a conventional oven in the absence of light; photocatalytic reactions are not involved. Nitrate was produced over the temperature range of 50-200°C following 2 hours of heating and gave yields that were linear with increases in temperature. Nitrate formation was also observed on certain arid land soils thermally treated in the normal atmosphere at 200°C for 2-50 hours or at 70°C for 15 hours or one week, although the rate of nitrate formation varied with different soils. Under the conditions employed, the yield of nitrate was a function of the area of the TiO2 or soils on the Petri dish. Formation of minor amounts of nitrite was also observed. Nitrate yields were produced in approximately equal amounts following a series of successive cycles of heating and extraction of the same soil fractions or TiO2 material indicating that the measured nitrate concentrations are not a result of soil nitrate release. Soils from Atacama Desert and Pyramid Lake have shown higher thermal activities and produced larger yields of nitrate than that measured for other soils tested. Additions of stoichiometric amounts of sodium, potassium or calcium hydroxide increased the amount of nitrate observed on both TiO 2 and on soils. Nitrates generated thermally on TiO2 or on soils from Pyramid Lake and from Atacama Desert have been enriched in 15N when heated in 5ml of 15N labeled nitrogen. The majority of d15N values of nitrate produced on TiO2 or on soil surfaces heated in air have d 15N ratios larger than that of atmospheric N. The isotopic composition of nitrate formed on heated soil surface has values similar to those observed for desert subsoil nitrates and linked to atmospheric processes. Nitrate was also detected on soils heated at 70°C suggesting that this process is likely occurring naturally on desert soils by the influence of sunlight heating. Consideration of these processes will likely raise the question on the origin of subsoil nitrate in arid and semiarid land and potentially help to explain the elevated nitrate levels observed in desert soils and groundwater which have been largely attributed to long-term atmospheric nitrate precipitation.

Al-Taani, Ahmed A.

362

The biological activity of structurally defined inositol glycans  

PubMed Central

Background The inositol glycans (IGs) are glycolipid-derived carbohydrates produced by insulin-sensitive cells in response to insulin treatment. IGs exhibit an array of insulin-like activities including stimulation of lipogenesis, glucose transport and glycogen synthesis, suggesting that they may be involved in insulin signal transduction. However, because the natural IGs are structurally heterogeneous and difficult to purify to homogeneity, an understanding of the relationship between structure and biological activity has relied principally on synthetic IGs of defined structure. Discussion This article briefly describes what is known about the role of IGs in signal transduction and reviews the specific biological activities of the structurally defined IGs synthesized and tested to date. Conclusion A pharmacophore for IG activity begins to emerge from the reviewed data and the structural elements necessary for activity are summarized.

Goel, Meenakshi; Azev, Viatcheslav N; d'Alarcao, Marc

2009-01-01

363

Effect of food waste compost on microbial population, soil enzyme activity and lettuce growth  

Microsoft Academic Search

The effect of food waste (FW) composted with MS® (Miraculous Soil Microorganisms) was compared with commercial compost (CC) and mineral fertilizer (MF) on bacterial and fungal populations, soil enzyme activities and growth of lettuce in a greenhouse. Populations of fungi and bacteria, soil biomass, and soil enzyme activities in the rhizosphere of FW treatments significantly increased compared to control (CON),

Jae-Jung Lee; Ro-Dong Park; Yong-Woong Kim; Jae-Han Shim; Dong-Hyun Chae; Yo-Sup Rim; Bo-Kyoon Sohn; Tae-Hwan Kim; Kil-Yong Kim

2004-01-01

364

Blending foundry sands with soil: Effect on dehydrogenase activity.  

PubMed

Each year U.S. foundries landfill several million tons of sand that can no longer be used to make metalcasting molds and cores. A possible use for these materials is as an ingredient in manufactured soils; however, potentially harmful metals and resin binders (used to make cores) may adversely impact the soil microbial community. In this study, the dehydrogenase activity (DHA) of soil amended with molding sand (clay-coated sand known as "green sand") or core sands at 10%, 30%, and 50% (dry wt.) was determined. The green sands were obtained from iron, aluminum, and brass foundries; the core sands were made with phenol-formaldehyde or furfuryl alcohol based resins. Overall, incremental additions of these sands resulted in a decrease in the DHA which lasted throughout the 12-week experimental period. A brass green sand, which contained high concentrations of Cu, Pb, and Zn, severely impacted the DHA. By week 12 no DHA was detected in the 30% and 50% treatments. In contrast, the DHA in soil amended with an aluminum green sand was 2.1 times higher (all blending ratios), on average, at week 4 and 1.4 times greater (30% and 50% treatments only) than the controls by week 12. In core sand-amended soil, the DHA results were similar to soils amended with aluminum and iron green sands. Increased activity in some treatments may be a result of the soil microorganisms utilizing the core resins as a carbon source. The DHA assay is a sensitive indicator of environmental stress caused by foundry sand constituents and may be useful to assess which foundry sands are suitable for beneficial use in the environment. PMID:15975632

Dungan, Robert S; Kukier, Urzsula; Lee, Brad

2005-06-21

365

Combined effects of cadmium and butachlor on soil enzyme activities and microbial community structure  

Microsoft Academic Search

The combined effects of cadmium (Cd, 10 mg\\/kg of soil) and butachlor (5, 10 and 50 mg\\/kg of soil) on enzyme activities and\\u000a microbial community structure were assessed in phaeozem soil. The result showed that phosphatase activities were decreased\\u000a in soils with Cd (10 mg\\/kg of soil) alone whereas urease acitivities were unaffected by Cd. Urease and phosphatase activities\\u000a were significantly reduced by

Jinhua Wang; Yitong Lu; Guoqing Shen

2007-01-01

366

Effects of mercury on microbial biomass and enzyme activities in soil  

Microsoft Academic Search

Mercury (Hg) is a persistent soil pollutant that affects soil microbial activity. We monitored the changes in soil microbial\\u000a biomass and activity of enzymes, including alkaline phosphatase, arylsulfatase, fluorescein diacetate (FDA) hydrolytic activity,\\u000a and o-diphenol oxidase (o-DPO) in three soils contaminated with different concentrations of Hg. Increasing levels of Hg, from 0.5 to 10 µmol\\/g of dried\\u000a soil, generally depressed

Cristiano Casucci; Benedict C. Okeke; William T. Frankenberger

2003-01-01

367

[Biological treatments for contaminated soils: hydrocarbon contamination. Fungal applications in bioremediation treatment].  

PubMed

Bioremediation is a spontaneous or controlled process in which biological, mainly microbiological, methods are used to degrade or transform contaminants to non or less toxic products, reducing the environmental pollution. The most important parameters to define a contaminated site are: biodegradability, contaminant distribution, lixiviation grade, chemical reactivity of the contaminants, soil type and properties, oxygen availability and occurrence of inhibitory substances. Biological treatments of organic contaminations are based on the degradative abilities of the microorganisms. Therefore the knowledge on the physiology and ecology of the biological species or consortia involved as well as the characteristics of the polluted sites are decisive factors to select an adequate biorremediation protocol. Basidiomycetes which cause white rot decay of wood are able to degrade lignin and a variety of environmentally persistent pollutants. Thus, white rot fungi and their enzymes are thought to be useful not only in some industrial process like biopulping and biobleaching but also in bioremediation. This paper provides a review of different aspects of bioremediation technologies and recent advances on ligninolytic metabolism research. PMID:15709784

Martín Moreno, Carmen; González Becerra, Aldo; Blanco Santos, María José

2004-09-01

368

Antibacterial activity of the streptomycetes isolated from marine soil sample  

Microsoft Academic Search

Streptomyces species are the source of 70% of known antibiotics and they live in the soil where they encounter antibiotics produced by competing microbes, including other actinomycetes. Antibacterial activity of streptomycetes isolated from muttukkad area in Tamil Nadu has been studied. A total of 50 streptomycetes were subjected to primary screening by cross streak method against Gram-positive (Staphylococcus aureus, S.epidermidis)

S. Usha Nandhini; M. Masilamani Selvam

2011-01-01

369

Plant Leaf Residue Decomposition, Nutrient Release and Soil Enzyme Activity  

Microsoft Academic Search

We studied the impact of plant leaf residue decompo sition and nutrient release of nitrogen and phosphorus of two weed species - Imperata cylindrica and Chromolaena odorata - and one native forest species - Phyllanthus discoideus - on soil enzyme activities in a pot experiment in the humid tropics of central Cameroon. We tested th e impact of plant leaf

Julia Dux; Lindsey Norgrove; Stefan Hauser; Barbara Wick; Ronald Kühne

370

The soil moisture active passive (SMAP) mission and validation  

Technology Transfer Automated Retrieval System (TEKTRAN)

The Soil Moisture Active Passive (SMAP) satellite will be launched by the National Aeronautics and Space Administration in October 2014. This satellite is the culmination of basic research and applications development over the past thirty years. During most of this period, research and development o...

371

Soil gas radon: a tool for exploring active fault zones  

Microsoft Academic Search

The profile of soil gas radon was monitored in five active fault sites in northern and northwestern Greece. Measurements were carried out during summer months, using CR-39 solid state nuclear track detectors (SSNTDs). The spatial distribution of radon along lines traversing the fault zones revealed anomalies, clearly connected to the local tectonic structure. Specifically, increased radon signals evolved on the

K. Ioannides; C. Papachristodoulou; K. Stamoulis; D. Karamanis; S. Pavlides; A. Chatzipetros; E. Karakala

2003-01-01

372

NASA Soil Moisture Active Passive (SMAP) Mission: Overview.  

National Technical Information Service (NTIS)

The Soil Moisture Active Passive (SMAP) mission is one of the first Earth observation satellites being developed by NASA in response to the National Research Council.s Decadal Survey (1). Its mission design consists of L-band radiometer and radar instrume...

D. Entekhabi E. Njoku K. Kellogg P. O'Neill

2011-01-01

373

Biological dinitrogen fixation by selected soil cyanobacteria as affected by strain origin, morphotype, and light conditions  

Microsoft Academic Search

The potential for N2 fixation by heterocystous cyanobacteria isolated from soils of different geographical areas was determined as nitrogenase\\u000a activity (NA) using the acetylene reduction assay. Morphology of cyanobacteria had the largest influence on NA determined\\u000a under light conditions. NA was generally higher in species lacking thick slime sheaths. The highest value (1446 nmol\\/h C2H4 per g fresh biomass) was

K. Hr?ková; M. Šimek; P. Hrouzek; A. Lukešová

2010-01-01

374

Effect of heavy metals on microbial biomass and activities in century old landfill soil.  

PubMed

A study was conducted to determine the effect of metals on soil microbial biomass and activities in landfill soils as well as normal background soil. The microbial biomass and activities were consistently higher in the landfill soils than in the background soil. Significant positive correlations existed between the microbial parameters and soil organic carbon. The landfill soils contained higher concentrations of metals (iron, manganese, copper, cadmium, lead and zinc) than did the background soil. Microbial parameters were negatively correlated with the metals, with inhibition increasing with the bioavailability of the metals. It is suggested that the metals affected microbial biomass and activities by behaving synergistically or additively with each other. Although the landfill soils had higher microbial biomass and activities than the background soil, due to higher organic matter content, the ratios of microbial parameters/organic carbon indicated that inhibition of microbial growth and activities had occurred due to metal stress. PMID:17370129

Bhattacharyya, P; Mitra, A; Chakrabarti, K; Chattopadhyay, D J; Chakraborty, A; Kim, K

2007-03-17

375

Winter biotic activity and production of CO[sub 2] in Siberian soils: A factor in the greenhouse effect  

SciTech Connect

Soil CO[sub 2] emissions at latitudes near 70[degrees]N in northeastern Siberia have been measured and occur at levels high enough to account for the observed winter maximum in atmospheric CO[sub 2] concentrations in this latitude. This CO[sub 2] is produced by biological activity at the bottom of the active layer above the permafrost. Ecological and anthropological factors may play a role in stimulating this CO[sub 2] emission. 35 refs., 3 figs.

Zimov, S.A.; Zimova, G.M.; Daviodov, S.P.; Daviodova, A.I.; Voropaev, Y.V.; Voropaeva, Z.V.; Prosiannikov, S.F.; Prosiannikova, O.V. (Pacific Inst. for Geography, Vladivostok (Russian Federation)); Semiletova, I.V. (Inst. of Chemistry, Vladivostok (Russian Federation)); Semiletov, I.P. (Pacific Oceanological Inst. Vladivostok (Russian Federation))

1993-03-20

376

Biologically active substances produced by antarctic cryptoendolithic fungi.  

PubMed

Researchers report results of laboratory studies of over 200 microbial strains of fungi, algae, cyanobacteria, and heterotrophic bacteria collected in the Ross Desert region of Antarctica. All of the 35 fungal strains produced substances that inhibited the growth of cyanobacteria and algae. The inhibitory effect of the biologically active substance was evident in crushed cell extract but less in spent broth. PMID:11539461

Ocampo-Friedmann, R; Friedmann, E I

1993-01-01

377

Biological activities and medicinal properties of neem (Azadirachta indica)  

Microsoft Academic Search

Neem (Azadirachta indica A. Juss) is perhaps the most useful traditional medicinal plant in India. Each part of the neem tree has some medicinal property and is thus commercially exploitable. During the last five decades, apart from the chemistry of the neem com- pounds, considerable progress has been achieved regarding the biological activity and medicinal appli - cations of neem.

Kausik Biswas; Ishita Chattopadhyay; Ranajit K. Banerjee; Uday Bandyopadhyay

378

Natural aliphatic oxygenated unsaturated acids. Synthesis and biological activity  

Microsoft Academic Search

The review is devoted to natural unsaturated acyclic acids containing oxygen functions. Compounds of the aceto-genin and propiogenin types containing hydroxy, oxo, and epoxy groups as well as ether, hydrofuran, and hydropyran fragments are considered. Data are given on the biological activities of the acids themselves or of natural compounds whose structural elements are unsaturated acids. The methodology and strategy

Alexander G. Tolstikov; Genrikh A. Tolstikov

1996-01-01

379

Screening of biological activity of Zosima absinthifolia fruits extracts  

Microsoft Academic Search

Zosima absinthifolia is a perennial herb which is distributed from Turkey to East Asia and Iran. It's fruits are used as a food spice in Iran and Turkey. In this work, we will study some biological activities of the fruits of the plant. The MTT assay indicated that methanol extract of the plant exhibited significant cytotoxic effects. In the DPPH

Seyed Mehdi Razavi; Alireza Ghasemiyan; Sakineh Salehi; Farahrouz Zahri

2009-01-01

380

A Thought on the Biological Activities of Black Tea  

Microsoft Academic Search

Tea is the most widely used ancient beverage in the world and black tea possesses many biological effects on the organisms. It acts as an effective antioxidant because of its free radical-scavenging and metal-chelating ability. Due to this, it is active against inflammation, clastogenesis, and several types of cancer. Tea reduces DNA damage and mutagenesis due to oxidative stress or

Vasundhara Sharma; L. Jagan Mohan Rao

2009-01-01

381

The Structure of a Biologically Active Influenza Virus Ribonucleoprotein Complex  

Microsoft Academic Search

The influenza viruses contain a segmented, single-stranded RNA genome of negative polarity. Each RNA segment is encapsidated by the nucleoprotein and the polymerase complex into ribonucleoprotein particles (RNPs), which are responsible for virus transcription and replication. Despite their importance, information about the structure of these RNPs is scarce. We have determined the three-dimensional structure of a biologically active recombinant RNP

Rocío Coloma; José M. Valpuesta; Rocío Arranz; José L. Carrascosa; Juan Ortín; Jaime Martín-Benito

2009-01-01

382

Iron and activated oxygen species in biology: The basic chemistry  

Microsoft Academic Search

This paper briefly presents a critical review concerning the chemical reactions involved when superoxide or hydrogen peroxide meet iron complexes. The data commented on are required for a correct interpretation of the chemical processes which play a paramount role in the biological activation of dioxygen and arise in normal metabolism as well as in pathological processes.

J. L. Pierre; M. Fontecave

1999-01-01

383

Thrombus versus Wall Biological Activities in Experimental Aortic Aneurysms  

Microsoft Academic Search

Background\\/Aim: The intraluminal thrombus (ILT) is considered to participate in abdominal aortic aneurysm (AAA) evolution. To assess whether this role proceeds via ILT influence on biological activity of the AAA wall, we studied the relationships between the levels of some relevant proteases and microparticles (MP) released by ILT versus wall in rat experimental AAAs. Methods and Results: Two weeks after

Michèle Coutard; Ziad Touat; Xavier Houard; Anne Leclercq; Jean-Baptiste Michel

2010-01-01

384

Biological activities and corresponding SARs of andrographolide and its derivatives.  

PubMed

In recent years, pharmaceutical chemists have synthesized large numbers of andrographolide derivatives, which bear important biological activities such as anti-inflammatory, antibacterial, antivirus, antitumor, antidiabetic, and antifeedant. Consequently, corresponding SARs were increasingly obvious. This paper aimed to review all the available literature in this field, highlighting the significant achievements on the structural modification and SARs of andrographolide and its derivatives. PMID:23438057

Zhou, Bin; Zhang, Dayong; Wu, Xiaoming

2013-02-01

385

Solar Energy Education. Renewable energy activities for biology  

SciTech Connect

An instructional aid for teachers is presented that will allow biology students the opportunity to learn about renewable energy sources. Some of the school activities include using leaves as collectors of solar energy, solar energy stored in wood, and a fuel value test for green and dry woods. A study of organic wastes as a source of fuel is included. (BCS)

Not Available

1982-01-01

386

EFFECTS OF COOKING ON THE BIOLOGICAL ACTIVITY OF FUMONISINS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Fumonisin (FB) mycotoxins are found in corn and corn-based foods. Cooking decreases FB concentrations under some conditions, but little is known about how cooking effects its biological activity. Baked cornread (BCB), pan-fried corn cakes (PFC), and deep fried corn fritters (DFF) were made from com ...

387

Amazing Soil Stories: Adventure and Activity Book [and] Teacher's Guide to the Activity Book.  

ERIC Educational Resources Information Center

The student activity book offers a variety of written exercises and "hands on" experiments and demonstrations for students at the fourth grade level. The book begins with a cartoon story that follows the adventures of a student investigating a soil erosion crisis and what her community can do to prevent soil erosion. Interspersed within the story…

California Association of Resource Conservation Districts, Sacramento.

388

Amazing Soil Stories: Adventure and Activity Book [and] Teacher's Guide to the Activity Book.  

ERIC Educational Resources Information Center

|The student activity book offers a variety of written exercises and "hands on" experiments and demonstrations for students at the fourth grade level. The book begins with a cartoon story that follows the adventures of a student investigating a soil erosion crisis and what her community can do to prevent soil erosion. Interspersed within the story…

California Association of Resource Conservation Districts, Sacramento.

389

Measuring denitrification activity in soils under pasture: Optimizing conditions for the short-term denitrification enzyme assay and effects of soil storage on denitrification activity  

Microsoft Academic Search

The short-term denitrification enzyme assay measures the potential denitrification activity of a soil in the field. The technique involves anaerobic incubation of soil samples and the measurement of N2O emission in the presence of C2H2. We examined the effects of incubation conditions and previous soil treatment on the denitrification enzyme activity (DEA) of two soils under permanent pasture. A standardized

J. Luo; R. E. White; P. Roger Ball; R. W. Tillman

1996-01-01

390

Total Chemical Synthesis of Biologically Active Vascular Endothelial Growth Factor  

PubMed Central

A 204 residue covalent-dimer vascular endothelial growth factor, with full mitogenic activity, was made by one-pot native chemical ligation from three unprotected peptide segments. The covalent structure of synthetic VEGF was confirmed by precise mass measurement, and the three dimensional structure of the synthetic protein molecule was determined by high resolution X-ray crystallography. Robust, practical synthetic access to biologically active VEGF will aid in the development of novel anti-angiogenic therapeutics.

Mandal, Kalyaneswar; Kent, Stephen B. H.

2012-01-01

391

Quantitative analysis of klimont, a new natural biologically active preparation  

Microsoft Academic Search

A method for quantitative determination of silicon, aluminum, and iron, the main active components in the natural biologically\\u000a active preparation klimont, is developed that ensures good reproducibility and accuracy. The limits for the content of these\\u000a elements are established and can be introduced into the “Quantitative Determination” section of the draft manufacturer’s pharmacopoeial\\u000a monograph for klimont.

A. N. Zhuchkov; A. S. Berlyand; M. S. Goizman; G. B. Tikhomirova; V. I. Yakusheva

2009-01-01

392

Secondary metabolites from Inula britannica L. and their biological activities.  

PubMed

Inula britannica L., family Asteraceae, is used in traditional Chinese and Kampo Medicines for various diseases. Flowers or the aerial parts are a rich source of secondary metabolites. These consist mainly of terpenoids (sesquiterpene lactones and dimmers, diterpenes and triterpenoids) and flavonoids. The isolated compounds have shown diverse biological activities: anticancer, antioxidant, anti-inflammatory, neuroprotective and hepatoprotective activities. This review provides information on isolated bioactive phytochemicals and pharmacological potentials of I. britannica. PMID:20336001

Khan, Abdul Latif; Hussain, Javid; Hamayun, Muhammad; Gilani, Syed Abdullah; Ahmad, Shabir; Rehman, Gauhar; Kim, Yoon-Ha; Kang, Sang-Mo; Lee, In-Jung

2010-03-10

393

Study of the Soil Isolates for Antimicrobial Activity  

PubMed Central

During the process of screening for a potent antimicrobial compound, a new strain was isolated from the soil sample of Thalaikunda village in Ooty, Tamil Nadu. That organism was name as NK2. It was found to be antagonistic to both bacterial and fungal test organisms. Production of antibiotic was more in a newly formulated broth. Antibiotic production reached maximum at the end of the 70 h of fermentation by stirred flask culture. The antimicrobial compound was extracted in n-butanol, ethyl acetate and methanol. Antimicrobial compound, which was produced by the soil isolate NK2 did not showed cytotoxic activity on Vero cell lines.

Srividya, A. R.; Saritha, G. S.; Suresh, B.

2008-01-01

394

Effect of root derived organic acids on the activation of nutrients in the rhizosphere soil  

Microsoft Academic Search

Four types of soils, including brown coniferous forest soil, dark brown soil, black soil, and black calic soil, sampled from\\u000a three different places in northeast China were used in this test. The functions of two root-derived organic acids and water\\u000a were simulated and compared in the activation of mineral nutrients from the rhizosphere soil. The results showed that the\\u000a organic

Chen Yong-liang; Guo Yu-qiang; Han Shi-jie; Zou Chun-jing; Zhou Yu-mei; Cheng Guo-ling

2002-01-01

395

Biological soil crusts are the main contributor to winter soil respiration in a temperate desert ecosystem of China  

NASA Astrophysics Data System (ADS)

Aims Biological soil crusts (BSCs) are a key biotic component of desert ecosystems worldwide. However, most studies carried out to date on carbon (fluxes) in these ecosystems, such as soil respiration (RS), have neglected them. Also, winter RS is reported to be a significant component of annual carbon budget in other ecosystems, however, we have less knowledge about winter RS of BSCs in winter and its contribution to carbon cycle in desert regions. Therefore, the specific objectives of this study were to: (i) quantify the effects of different BSCs types (moss crust, algae crust, physical crust) on the winter RS; (ii) explore relationships of RS against soil temperature and water content for different BSCs, and (iii) assess the relative contribution of BSCs to the annual amount of C released by RS at desert ecosystem level. Methods Site Description The study sites are located at the southeast fringe of the Tengger Desert in the Shapotou region of the Ningxia Hui Autonomous Region [37°32'N and 105°02'E, at 1340 m above mean sea level (a.m.s.l.)], western China. The mean daily temperature in January is -6.9°C , while it is 24.3°C in July. The mean annual precipitation is 186 mm, approximately 80% of which falls between May and September. The annual potential evaporation is 2800 mm. The landscape of the Shapotou region is characterized by large and dense reticulate barchans chains of sand dunes that migrate south-eastward at a velocity of 3-6 m per year. The soil is loose, infertile and mobile and can thus be classified as orthic sierozem and Aeolian sandy soil. Additionally, the soil has a consistent gravimetric water content that ranges from 3 to 4%. The groundwater in the study area is too deep (>60 m) to support large areas of the native vegetation cover; therefore, precipitation is usually the only source of freshwater. The predominant native plants are Hedysarum scoparium Fisch. and Agriophyllum squarrosum Moq., Psammochloa cillosa Bor, which scattered distribute with cover about 1% of the entire study area. Prior to revegetation, straw-checkerboards approximately 1×1 m2 in area were constructed using wheat or rice straw to stabilize the dune surface and allow time for the planted xerophytic shrubs to adapt to the new environment. In 1956, the following 2-year-old xerophytic shrub seedlings were planted within the checkerboard at a density of 16 individuals per 100 m2 and grown without irrigation: Artemisia ordosica Krasch, H. scoparium Fisch, Calligonum mongolicum Turc'z, Caragana microphylla Lam., Caragana korshinskii Kom, Salix gordejevii and Atraphaxis bracteata A.Los. The stabilized area was then expanded to parallel areas in 1964 and 1982 using the same method and species. As a result, the initial stages of change that have occurred at these sites were similar. After more than fifties years succession, the predominant plants are semi-shrubs, shrubs, forbs, and grasses at present and BSCs formed. The common BSCs in the region may be dominated by cyanobacteria, algae, lichens and mosses, or any combination of these organisms. Cyanobacteria species include Microcolous vaginatus Gom., Hydrocoleus violacens Gom., Lyngbya crytoraginatus Schk., Phormidium amblgum Gom., P. autumnale (Ag.) Gom., P. foveolarum (Mont.) Gom. and Phormidium luridum (Kutz) Gom. etc; algal species mainly include Anabaena azotica Ley, Euglena sp., Hantzschia amphioxys var capitata Grum, Oscillatoria obscura Gom., O. pseudogeminate G. Schm. And Scytonema javanicum (Kutz) Bornet Flash etc; lichen species include Collema tenax (Sw.) Ach., Endocarpon pusillum Hedw.; and moss species are dominated by Bryum argenteum Hedw., Didymodon constrictus (Mitt.) Saito., Tortula bidentata Bai Xue Liang and T. desertorum Broth.. Experimental Design and Rs measurements On October 2010, We selected the moss-dominated BSCs at four revegetation sites and natural vegetation sites, in which 3 replicated plots were selected randomly. In each plot, olyvinyl chloride (PVC) collar (lenth 10 cm, internal diameter 10cm ) were inserted 7 cm into the soil. During the

He, M. Z.

2012-04-01

396

Effects of initial soil condition on the effectiveness of biological geotextiles in reducing interrill runoff and erosion  

NASA Astrophysics Data System (ADS)

The effectiveness of a surface cover material (e.g. geotextiles, rock fragments, mulches, vegetation) in reducing runoff and soil erosion rates is often only assessed by the fraction of the soil surface covered. However, there are indications that soil structure has important effects on the runoff and erosion-reducing effectiveness of the cover materials. This study investigates the impact of initial soil condition (i.e. fine tilth versus sealed soil surface) on the effectiveness of biological geotextiles in increasing infiltration rates and in reducing runoff and interrill erosion rates on a medium and steep slope gradient. Rainfall was simulated during 60 minutes with an intensity of 67 mm h-1 on an interrill erosion plot having two slope gradients (i.e. 15 and 45%) and filled with an erodible sandy loam. Five biological and three simulated geotextiles with different cover percentage were tested on two simulated initial soil conditions (i.e. fine tilth and sealed soil surface). Final infiltration rates on a sealed soil surface (7.5-18.5 mm h-1) are observed after ca. 10 minutes of rainfall compared to ca. 50 minutes of rainfall on an initial seedbed (16.4-56.7 mm h-1). On the two tested slope gradients, significantly (? = 0.05) smaller runoff coefficients (RC) are observed on an initial seedbed (8.2% < RC < 59.8%) compared to a sealed soil surface (75.7% < RC < 87.0%). On an initial seedbed, decreasing RC are observed with an increasing simulated geotextile cover. However, on an initial sealed soil surface no significant effect of simulated geotextile cover on RC is observed. On a 15% slope gradient, calculated b-values from the mulch factor equation equalled 0.054 for an initial fine tilth and 0.022 for a sealed soil surface, indicating a higher effectiveness of geotextiles in reducing interrill erosion on a fine tilth compared to a sealed soil surface. Therefore, this study demonstrates the importance of applying geotextiles on the soil surface before the surface tilth is sealed due to rainfall. The effect of soil structure on the effectiveness of a surface cover in reducing runoff and interrill erosion rates, as indicated by the results of this study, needs to be incorporated in soil erosion prediction models.

Smets, T.; Poesen, J.

2009-04-01

397

Impacts of simulated acid rain on soil enzyme activities in a latosol.  

PubMed

Acid rain pollution is a serious environmental problem in the world. This study investigated impacts of simulated acid rain (SAR) upon four types of soil enzymes, namely the catalase, acid phosphatase, urease, and amylase, in a latosol. Latosol is an acidic red soil and forms in the tropical rainforest biome. Laboratory experiments were performed by spraying the soil columns with the SAR at pH levels of 2.5, 3.0, 3.5., 4.0, 4.5, 5.0, and 7.0 (control) over a 20-day period. Mixed results were obtained in enzyme activities for different kinds of enzymes under the influences of the SAR. The catalase activities increased rapidly from day 0 to 5, then decreased slightly from day 5 to 15, and finally decreased sharply to the end of the experiments, whereas the acid phosphatase activities decreased rapidly from day 0 to 5, then increased slightly from day 5 to 15, and finally decreased dramatically to the end of the experiments. A decrease in urease activities was observed at all of the SAR pH levels for the entire experimental period, while an increase from day 0 to 5 and then a decrease from day 5 to 20 in amylase activities were observed at all of the SAR pH levels. In general, the catalase, acid phosphatase, and urease activities increased with the SAR pH levels. However, the maximum amylase activity was found at pH 4.0 and decreased as the SAR pH increased from 4.0 to 5.0 or decreased from 4.0 to 2.5. It is apparent that acid rain had adverse environmental impacts on soil enzyme activities in the latosol. Our study further revealed that impacts of the SAR upon soil enzyme activities were in the following order: amylase>catalase>acid phosphatase>urease. These findings provide useful information on better understanding and managing soil biological processes in the nature under the influence of acid rains. PMID:20701974

Ling, Da-Jiong; Huang, Qian-Chun; Ouyang, Ying

2010-08-10

398

Soil moisture regulates the biological response of elevated atmospheric CO 2 concentrations in a coupled atmosphere biosphere model  

Microsoft Academic Search

Terrestrial biosphere models\\/land surface models are routinely used to study the effects of CO2 doubling and climate change. The objective of this study is to show that the biological response associated with CO2 doubling is important, and that the effects intrinsically depend on the soil moisture state. Therefore, using a coupled biosphere–atmosphere model, we tested the hypothesis that the biological

Dev Niyogi; Yongkang Xue

2006-01-01

399

[Soil catalase activity of main plant communities in Leymus chinensis grassland in northeast China].  

PubMed

The seasonal dynamics of soil catalase activity of three different plants communities in Leymus chinensis grassland in northeast China were in a parabolas shape. The seasonal variation of Chloris virgata community was greater than those of Leymus chinensis community and Puccinellia tenuiflora community, and "seed effect" might be the main reason. The correlation between the activity of soil catalase in different soil layers and environmental factors were analyzed. The results showed that the activity of soil catalase was decreased gradually with depth of soil layer. The activity of soil catalase was closely correlated with rainfall and air temperature, and it was affected by soil temperature, soil moisture, and their interactions. The correlation between the activity and aboveground vegetation was very significant, and the growing condition of plant communities could be reflected by the activity of soil catalase. PMID:12216391

Lu, Ping; Guo, Jixun; Zhu, Li

2002-06-01

400

Probing the Activities of Soil Invertebrates Using Stable Isotope Approaches  

NASA Astrophysics Data System (ADS)

Soil dwelling invertebrates play a vital role in determining the physical properties and nutrient cycling in soil. Their diverse behaviours influence organic litter, water and gas transport. They impact on other soil biota, e.g. microbes, plants, other invertebrates, etc. via their various grazing and predatory activities, and their role in the comminution of litter influences the activities of other decomposer organisms. However, major challenges exist in the study of the activities of such invertebrates due to the small sizes of many of the key organisms and the opaque nature of soil. This paper will provide an overview of a number of new approaches that have been developed to investigate the behaviours of soil invertebrates. The techniques we employ are based on the use of stable isotopes, exploiting both natural abundance labelling and artificially isotopically enriched tracers. Experiments range from simple feeding and choice experiments in laboratory arenas to pot-based microcosm studies, and field experiments (Chamberlain et al., 2004; Black et al. in press). The philosophy underpinning this research is to exploit fundamental biochemical information to determine the activities of organisms. Thus, compound-specific stable isotope determinations are one of our major goals since these yield high specificity stable isotopic information, often at the biochemical building block level. Compound-specific approaches also have the virtue of enhancing analytical sensitivity, such that the ? 13C values of the biochemical components of individual specimens of low microgram-sized organisms, i.e. mesoinvertebrates, can be recorded their behaviours investigated (Evans et al., 2003; Black et al. in press).

Evershed, R. P.

2004-12-01

401

Synthesis and biological evaluation of an electronically activated isooxacephem.  

PubMed

New isooxacephem (+/-)-3-ethyl 2-hydrogen (6RS,7RS)-8-oxo-7-(phenylacetamido)-4-oxa-1-azabicyclo [4.2.0]oct-2-ene-2, 3-dicarboxylate (8) was synthesized from (+/-)-dibenzyl 2-[cis-2-oxo-3-(phenylacetamido)-4-styryl-1-azetidinyl]-2-[t- butyldimethylsiloxy(methoxycarbonyl)methyl]malonate (1) in six steps. This bicyclic beta-lactam was found to possess notable biological activities against several pathogenic microorganisms in vitro, including Staphylococcus aureus 95, S. aureus FDA 209P, Escherichia coli ATCC 39188, Salmonella typhi O-901, Pseudomonas aeruginosa 18S-H, P. aeruginosa 1101-75, and Klebsiella pneumoniae NCTC 418. The electronic activation of the beta-lactam moiety by an ester group plays a prominent role in the biological activity of this novel isooxacephem. PMID:8879559

Hakimelahi, G H; Tsay, S C; Tso, H H; Ramezani, Z; Hwu, J R

1996-08-01

402

Similar Biological Activities of Two Isostructural Ruthenium and Osmium Complexes  

SciTech Connect

In this study, we probe and verify the concept of designing unreactive bioactive metal complexes, in which the metal possesses a purely structural function, by investigating the consequences of replacing ruthenium in a bioactive half-sandwich kinase inhibitor scaffold by its heavier congener osmium. The two isostructural complexes are compared with respect to their anticancer properties in 1205?Lu melanoma cells, activation of the Wnt signaling pathway, IC50 values against the protein kinases GSK-3? and Pim-1, and binding modes to the protein kinase Pim-1 by protein crystallography. It was found that the two congeners display almost indistinguishable biological activities, which can be explained by their nearly identical three-dimensional structures and their identical mode of action as protein kinase inhibitors. This is a unique example in which the replacement of a metal in an anticancer scaffold by its heavier homologue does not alter its biological activity.

Maksimoska,J.; Williams, D.; Atilla-Gokcumen, G.; Smalley, K.; Carroll, P.; Webster, R.; Filippakopoulos, P.; Knapp, S.; Herlyn, M.; Meggers, E.

2008-01-01

403

Molecular biological access to the chemistry of unknown soil microbes: a new frontier for natural products  

Microsoft Academic Search

Cultured soil microorganisms have provided a rich source of natural-product chemistry. Because only a tiny fraction of soil microbes from soil are readily cultured, soil might be the greatest untapped resource for novel chemistry. The concept of cloning the metagenome to access the collective genomes and the biosynthetic machinery of soil microflora is explored here.

Jo Handelsman; Michelle R. Rondon; Sean F. Brady; Jon Clardy; Robert M. Goodman

1998-01-01

404

International approach to assessing soil quality by ecologically-related biological parameters  

Microsoft Academic Search

Soil quality represents an integral value of the compositional structures and natural functions of soil in relation to soil use and environmental conditions on site. Among the indigenous soil components, different organisms and especially microorganisms play a key role in ecologically important biogeochemical processes. In that way, soil microorganisms contribute to the maintenance of the matter and energy transfer in

Z. Filip

2002-01-01

405

Biological activity in Technosols as a key factor of their structure  

NASA Astrophysics Data System (ADS)

The studies of the dynamics of organic matters within soils, show that their structural stability depends on the biological activity bound to the degradation of organic products. We wondered what it was for Technosols there. We then tried to specify the contribution of this biological activity to the structure of three contrasted technosols : - Technosol 1: a material originated from a former steel industry containing steel and coke residues, which was deposited two years ago in lysimetric plots - Technosol 2: a constructed soil (30 months) resulting from the combination of paper-mill sludge, thermally treated soil material excavated from a former coking plant site, and green-waste compost - Technosol 3: 30 years old technosol developed on flotation ponds of a former steel mill with strong metallic pollution, on which grows a forest ecosystem If these 3 technosols presented initially a similar organic carbon content (around 70 g.kg-1), the origin of organic matters was different A follow-up of the structural stability of these 3 systems, based on techniques of granulometric soil fractionation and morphological/analytical characterization at ultrastructural scale (TEM/EDX), was realized. Results showed the specific contribution of organic matters to the formation of stable organo-mineral associations, in particular those belonging to (0-50 ?m) fraction. They mainly involved organic matter from vegetal origin coming from the spontaneous colonization of these 3 sites, but also from microbial origin corresponding to rhizospheric bacteria producing exopolymers. Organic matters from the compost and cellulosic fibers from the paper-mill sludge also contributed to the formation of organo-mineral associations all the more that compost was also a source of microorganisms. Organic matters were also associated to pollutant metallic elements (Pb, Zn, Mn) initially brought by the materials, then highlighting their possible transfer and questioning about their (bio)availability. HAP also contributed to the aggregation of technogenic constituents in Technosol 1. The biological activity generated by the presence of exogenous organic matter is thus in short (0-2 years) and mean (30 years) terms, a key factor of the structuration and by there of the pedogenesis of Technosols.

Watteau, Françoise; Villemin, Geneviève; Bouchard, Adeline; Monserié, Marie-France; Séré, Geoffroy; Schwartz, Christophe; Morel, Jean-Louis

2010-05-01

406

Effect of biological soil crusts of the Sahel (Niger) on wind erosion  

NASA Astrophysics Data System (ADS)

Biological Soil crusts (BSC) are widespread in semi arid areas like the Sahel where they are colonizing sandy soils prone to water and wind erosions. This study aimed at understanding the effect of BSC on wind erosion. It was performed at the ICRISAT Sahelian Center of Sadore (Niger) in an old fallow. The annual rainfall depth is around 560 mm. The experimental set up comprised five circular plots (diameter 10 m) with BSC cover varying from 5 % to 40 %. Vegetation and litter inside the experimental plots were removed without breaking the crusts during the whole experiment duration (1.5 year), while shrubs and annual grass were maintained around the plots to minimize wind erosion. Both horizontal flux of wind-blown sediment and wind erosion threshold were measured with BSNE sand catchers and Sensit recording saltating particles impacts. Meteorological parameters such as wind velocity and direction and rainfall were also monitored. The measured flux followed the classical cycle of wind erosion in the Sahel with a maximum occurring by the beginning of the rainy season from May to July. Wind erosion thresholds did not show important variation during the whole year. Moreover they are almost the same (about 13 m/s) whatever the plot, i.e. whatever the BSC cover percentage. This value is higher than that measured on cultivated field. This suggest that the threshold is likely linked to the presence of loose sand particles at the crust surface and do not represent the real threshold of BSC. In the same way, there is still not a clear relationship between the flux intensity and the BSC cover. This seems to indicate that the physical crusts colonized by BSC play also a role in the soil erodibility to wind erosion as it was clearly demonstrated in the case of water erosion.

Rajot, J. L.; Paris, R.; Malam Issa, O.; Maman, A.; Abdourhamane Touré, A.; Valentin, C.; Marticorena, B.

2012-04-01

407

Structure-activity relationships of ?s-casein peptides with multifunctional biological activities.  

PubMed

Multifunctional bioactive peptides have a wider role in modulating physiological functions and possess multiple biological activities. Peptides from bovine milk with sequences QKALNEINQF [p10] and TKKTKLTEEEKNRL [p14] from ?-S2 casein f (79-88) and ?-S2 casein f (148-161) were identified to be having multifunctional biological activities and were synthesized. These synthesized peptides show various biological activities like angiotensin-converting enzyme inhibition, prolyl endopeptidase inhibition, antioxidant, and antimicrobial activities. The mode of antimicrobial mechanism was studied and p10 shows depolarization of cell membrane, whereas p14 was found to display DNA-binding activity. Structural studies envisaged backbone flexibility, for differences in their mode of action. Peptide structure function studies were correlated to understand their multifunctional biological activity. PMID:23963991

Sistla, Srinivas

2013-08-21

408

Measurements of Microbial Community Activities in Individual Soil Macroaggregates  

SciTech Connect

The functional potential of single soil aggregates may provide insights into the localized distribution of microbial activities better than traditional assays conducted on bulk quantities of soil. Thus, we scaled down enzyme assays for {beta}-glucosidase, N-acetyl-{beta}-D-glucosaminidase, lipase, and leucine aminopeptidase to measure of the enzyme potential of individual aggregates (250-1000 {mu}m diameter). Across all enzymes, the smallest aggregates had the greatest activity and the range of enzyme activities observed in all aggregates supports the hypothesis that functional potential in soil may be distributed in a patchy fashion. Paired analyses of ATP as a surrogate for active microbial biomass and {beta}-glucosidase on the same aggregates suggest the presence of both extracellular {beta}-glucosidase functioning in aggregates with no detectable ATP and also of relatively active microbial communities (high ATP) that have low {beta}-glucosidase potentials. Studying function at a scale more consistent with microbial habitat presents greater opportunity to link microbial community structure to microbial community function.

Bailey, Vanessa L.; Bilskis, Christina L.; Fansler, Sarah J.; McCue, Lee Ann; Smith, Jeff L.; Konopka, Allan

2012-05-01

409

Biological maturity and primary school children's physical activity: Influence of different physical activity assessment instruments  

Microsoft Academic Search

Biological maturation may attenuate hypothesized sex differences in children's physical activity but overall the evidence for this is equivocal. In this study, we investigated how the selection of different physical activity assessment instruments affects the detected relationship between biological maturation and late primary school children's physical activity. Altogether, 175 children (97 girls, 78 boys) aged 10.6±0.3 years completed the PAQ-C

Stuart J. Fairclough; Lynne M. Boddy; Nicola D. Ridgers; Gareth Stratton; Sean Cumming

2011-01-01

410

Biological activity of new aza analogues of quinolones  

Microsoft Academic Search

A series of novel derivatives of 4H-pyrido[1,2-a]pyrimidine, 1,4-dihydro-4-oxo-1,5-naphthyridine and 1,4-dihydro-4-oxo-1,6-naphthyridine were prepared and their biological\\u000a activity was compared with that of nalidixic acid. Thein vitro antibacterial activity of the tested compounds was lower than that of nalidixic acid except for two agents,1b and2c, with a higher activity againstEnterococcus faecalis. The compounds were tested for their ability to cure four plasmids

A. Belicová; M. Seman; V. Milata; D. Ilavský; L. Ebringer

1997-01-01

411

Effect of organic, sustainable, and conventional management strategies in grower fields on soil physical, chemical, and biological factors and the incidence of Southern blight  

Microsoft Academic Search

The objectives of our research were to evaluate the impact of organic, sustainable, and conventional management strategies in grower fields on soil physical, chemical, and biological factors including soil microbial species and functional diversity and their effect on the Basidiomycete plant pathogen Sclerotium rolfsii, causal agent of Southern blight. Soils from 10 field locations including conventional, organic and sustainable farms

Bo Liu; Cong Tu; Shuijin Hu; Marcia Gumpertz; Jean Beagle Ristaino

2007-01-01

412

A numerical model (MISER) for the simulation of coupled physical, chemical and biological processes in soil vapor extraction and bioventing systems  

Microsoft Academic Search

The efficiency and effectiveness of soil vapor extraction (SVE) and bioventing (BV) systems for remediation of unsaturated zone soils is controlled by a complex combination of physical, chemical and biological factors. The Michigan soil vapor extraction remediation (MISER) model, a two-dimensional numerical simulator, is developed to advance our ability to investigate the performance of field scale SVE and BV systems

Klaus M. Rathfelder; John R. Lang; Linda M. Abriola

2000-01-01

413

Impacts of insect biological control on soil N transformations in Tamarix-invaded ecosystems in the Great Basin  

Technology Transfer Automated Retrieval System (TEKTRAN)

Understanding the impacts of insect biological control of Tamarix spp. on soil nitrogen (N) transformations is important because changes to N supply could alter plant community succession. We investigated short-term and longer-term impacts of herbivory by the northern tamarisk beetle (Diorhabda cari...

414

Is an Enhanced Soil Biological Community, Relative to Conventional Neighbours, a Consistent Feature of Alternative (Organic and Biodynamic) Agricultural Systems?  

Microsoft Academic Search

A review was conducted of studies which compare the soil biological community on farms where plant nutrition is managed in a ‘conventional’ manner (addition of synthetic easily-soluble fertilizers) with farms which adopt ‘alternative’ fertilizer strategies (organic or biodynamic). Such alternative strategies include additions of natural minerals, composts or manures, and growth of green manure crops or inclusion of legumes in

Megan Ryan

1999-01-01

415

Abundance of Iron-Oxidizing Thiobacilli and Biological Sulfur Oxidation Potential from Soil Impacted by Coal and Coal Refuse Piles  

Microsoft Academic Search

This study was conducted to assess the abundance of iron-oxidizing bacteria and biological sulfur oxidation potential from soil impacted by coal and coal refuse from two coal-burning electric power facilities located at the U.S. Department of Energy's Savannah River Site (Aiken, S.C.) and the South Carolina Electric and Gas Site at Beech Island, S. C.

B. Klubek; C. Schmidt; D. C. Adriano

1998-01-01

416

Ecophysiological analysis of moss-dominated biological soil crusts and their separate components from the Succulent Karoo, South Africa.  

PubMed

Biological soil crusts, formed by an association of soil particles with cyanobacteria, lichens, mosses, fungi and bacteria in varying proportions, live in or directly on top of the uppermost soil layer. To evaluate their role in the global carbon cycle, gas exchange measurements were conducted under controlled conditions. Moss-dominated soil crusts were first analyzed as moss tufts on soil, then the mosses were removed and the soil was analyzed separately to obtain the physiological response of both soil and individual moss stems. Net photosynthetic response of moss stems an