Extinction and ecosystem function in the marine benthos     

Solan M  Cardinale BJ  Downing AL  Engelhardt KA  Ruesink JL  Srivastava DS 《Science (New York, N.Y.)》2004,306(5699):1177-1180

Rapid changes in biodiversity are occurring globally, yet the ecological impacts of diversity loss are poorly understood. Here we use data from marine invertebrate communities to parameterize models that predict how extinctions will affect sediment bioturbation, a process vital to the persistence of aquatic communities. We show that species extinction is generally expected to reduce bioturbation, but the magnitude of reduction depends on how the functional traits of individual species covary with their risk of extinction. As a result, the particular cause of extinction and the order in which species are lost ultimately govern the ecosystem-level consequences of biodiversity loss.  相似文献   

Daily variation in concentration of cortisol in plasma in intact and hypophysectomized gulf killifish   总被引：1，自引：0，他引：1  

A K Srivastava  A H Meier 《Science (New York, N.Y.)》1972,177(44):185-187

A daily variation in concentration of cortisol in plasma is synchronized by a 12-hour daily photoperiod in intact as well as in hypophysectomized fish. The daily rhythm in concentration of the adrenal steroid does not depend on a daily rhythm in the concentration of pituitary adrenocorticotropic hormone.  相似文献   

Plant defense activation and management of tomato root rot by a chitin-fortified <Emphasis Type="Italic">Trichoderma/Hypocrea</Emphasis> formulation     

Manoj Kumar Solanki  Nidhi Singh  Rajesh Kumar Singh  Pratiksha Singh  Alok K. Srivastava  Sudheer Kumar  Prem L. Kashyap  Dilip K. Arora 《Phytoparasitica》2011,39(5):471-481

Tomato root rot caused by Rhizoctonia solani is a major soilborne disease resulting in significant yield loss. The culture filtrates of six isolates of Trichoderma/Hypocrea species were evaluated for in vitro production of hydrolytic enzymes. Results demonstrated that all the six isolates were able to produce chitinase, β-1, 3 glucanase and protease in the range of 76–235 μmol GlcNAc min^-1 mg^-1 protein, 31.90–37.72 nmol glucose min^-1 mg^-1 proteins and 63.05–86.22 μmol min^-1 mg^-1 proteins, respectively. Trichoderma/Hypocrea-based formulation(s) were prepared with chitin (1% v:v) and CMC (0.5% w:v) for root rot management in a greenhouse. Root dip application with bioformulation(s) resulted in a significant reduction of the root rot index. In addition, bioformulations increased plant growth attributing traits significantly relative to untreated control. Accumulation of total phenols, peroxidase, polyphenoloxidase and phenylalanine ammonia lyase increased in chitin-supplemented Trichoderma/Hypocrea formulation-treated plants challenged with R. solani. The results suggest that chitin-fortified bioformulation(s) could be an effective system to control root rot of tomato in an eco-compatible manner.  相似文献   

Potential of Eisenia foetida for Sustainable and Efficient Vermicomposting of Fly Ash     

S. K. Gupta  Anamika Tewari  Richa Srivastava  R. C. Murthy  Saurabh Chandra 《Water, air, and soil pollution》2005,163(1-4):293-302

Vermicomposting of fly ash has been attempted, using red earthworm, Eisenia foetida. Fly ash, which was obtained from thermal power station, was mixed with cowdung in different proportions (20, 40, 60 and 80%). These mixtures were used as feed for earthworms, and after 30 days, vermicast recovery, worm zoomass and numbers of juveniles produced were recorded. A total of six runs each of 30 days were conducted during the whole study. Concentrations of heavy metals in different mixtures of fly ash–cowdung, before and after vermicomposting and in the earthworms used in the study were also estimated. Results show maximum output of vermicasts and maximum number of juveniles produced was in reactors with 40% fly ash while maximum weight gain by earthworm was in 20% fly ash vermireactors. Performance of vermireactors up to 60% fly ash was more or less similar but at 80% fly ash, there is a marked reduction in overall performance of the reactors. Chemical analysis of different samples of fly ash–cowdung mixtures prior to vermicomposting revealed high concentrations of zinc, chromium, lead, nickel and copper. Chemical analysis of vermicomposted samples showed 30–50% reduction in heavy metals up to 60% fly ash and 10–30% reduction in 80% fly ash. Metal analysis of earthworms revealed considerable bioaccumulation of heavy metals in their body. The Present study indicates the feasibility of E. foetida for mitigating the toxicity of metals and up to 60% fly ash–cowdung mixtures can be used for sustainable and efficient vermicomposting.  相似文献   

Effects of crop growth and soil treatments on microbial C,N, and P in dry tropical arable land   总被引：1，自引：0，他引：1  

S. C. Srivastava  J. P. Lal 《Biology and Fertility of Soils》1994,17(2):108-114

We studied the dynamics of microbial C, N, and P in soil cropped with rice (Oryza sativa) and lentils (Lens culinaris) in a dryland farming system. The crop biomass and grain yield were also studied. The microbial biomass and its N and P contents were larger under the lentil than under the rice crop. Microbial nutrients decreased as the crops grew and then increased again. Farmyard manure and NPK fertilizer applications increased the level of microbial nutrients, crop biomass, and grain yield by 35–80%, 55–85%, and 74–86%, respectively. However, these applications had no significant effect on most of the soil physicochemical properties in the short term. The microbial biomass was correlated with the crop biomass and grain yield. The calculated flux of N and P through the microbial biomass ranged from 30–45 and 10–19 kg ha^-1 year^-1, respectively. Cultivation of a cereal crop followed by a leguminous crop sustains higher levels of microbial nutrients and hence greater fertility in impoverished tropical arable soils. The soil microbial biomass appears to contribute significantly to crop productivity by releasing nutrients, and applications of manure, either alone or with fertilizers, promote this effect more strongly than the application of NPK fertilizers alone.  相似文献   

Biochemical changes in duck weed after cadmium treatment. Enhancement in senescence     

Alaka Srivastava  V. S. Jaiswal 《Water, air, and soil pollution》1990,50(1-2):163-170

The effect of Cd on biochemical changes in the free floating duck weed (Spirodela polyrrhiza L. SP₂₀) was studied. Cadmium enhanced senescence; enzymes like peroxidase, protease and phosphatases, which are known as a marker of senescence, were increased after Cd treatment. Nitrate reductase activity was also increased. With increasing Cd levels, Ca, Mg, and Zn concentrations in the plant were decreased while the Fe concentration was increased.  相似文献   

Pharmacokinetics and biochemical effects of diacetyl monoxime in Bubalus bubalis     

A K Srivastava  J K Malik 《Acta veterinaria Hungarica》1986,34(3-4):231-238

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Effects of heating and freezing on the viability of sarcocysts of Sarcocystis levinei from cardiac tissues of buffaloes     

P S Srivastava  A K Saha  S R Sinha 《Veterinary parasitology》1986,19(3-4):329-332

Dogs fed buffalo heart muscle containing sarcocysts of Sarcosystis levinei and heated at 65-75 degrees C did not shed sporocysts, whereas other dogs fed infected heart muscle heated between 40 and 60 degrees C shed sporocysts. Dogs fed infected heart muscle stored at -4 degrees C for 48 h did not shed sporocysts, but those fed similar infected tissues stored at -2 degrees C for 24 h shed sporocysts. The results indicate that sarcocysts of S. levinei are rendered noninfective by heating to 65 degrees C or by freezing at -4 degrees C.  相似文献   

Properties of phosphoenolpyruvate carboxykinase of goat liver     

R S Dhanotiya  R Bhardwaj  H S Srivastava 《Archiv fuer experimentelle veterinaermedizin》1987,41(4):486-490

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The experimental production of big liver and spleen disease in broiler breeder hens     

SK CRERAR  GM CROSS 《Australian veterinary journal》1994,71(12):414-417

SUMMARY Big liver and spleen disease (BLS) was reproduced experimentally by intravenous (IV) and oral (PO) administration of BLS inocula to susceptible broiler breeder hens 34 to 36 weeks of age. Serological and pathological signs of BLS similar to those seen in the natural disease occurred in inoculated and in-contact birds. Splenomegaly was the earliest and often the only necropsy finding, with hepatomegaly and kidney enlargement occurring in some birds later in the course of the disease. After IV administration, serum antigen was detected between 2 and 4 weeks, and antibody between 3 and 5 weeks. After PO administration, antigen was detected between 2 and 4 weeks, and antibody between 3 and 6 weeks. Antibody persisted in all birds to the end of the experiment (6 weeks), and horizontal transmission probably occurred since in-contact birds developed BLS. Liver probably contained the highest concentration of BLS agent because it had the highest infectivity.  相似文献