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The upper incipient lethal temperatures of the freshwater mullet, Rhinomugil corsula, acclimated to 15, 20, 25, 30 and 35°C in fresh water, were 32.4, 34.1, 36.0, 36.2 and 36.5°C respectively, and the corresponding lower lethal temperatures were 10.5, 11.5, 13.2, 15.8 and 19.5°C. The mullet has a total tolerance (area of thermal polygon) of 569°C with an upper and lower thermal tolerance of 253 and 316°C2. Likewise, the total resistance of the mullet was 391°C2, with upper and lower resistance zones of 181 and 210°C respectively. The upper critical temperatures of swimming inhibition of R. corsula (17.2 cm; acclimation 30°C), determined in a swimming tunnel, were 35.2, 34.6 and 34.2 for water current velocities of 38, 62 and 77 cm s?1 respectively. The corresponding lower critical temperatures were 26.2, 27.5 and 28.1°C. These results indicated the stenothermal nature of the mullet by comparison with other fishes, e.g. Tilapia mossambica.In tests on the influence of ambient salinity on thermal resistance, R. corsula survived longest at 7‰ (iso-osmotic salinity). At salinities above and below this point, survival times were shorter at any lethal temperature. In a tentative scheme for quantification of stress due to temperature and salinity at death (after acclimation to 30°C and tested at 37°C), the hypo-osmotic and hyper-osmotic stress were estimated to be 50 and 31% of the thermal stress (100%) respectively. 相似文献
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Path-Coefficient Analysis of Leaf-Anatomical Characters Affecting Frost Injury in Potato 总被引:1,自引:0,他引:1
Correlation and path-coefficient analysis for leaf-anatomical characters affecting frost injury was carried out in twenty eight varieties and accessions belonging to several wild and cultivated tuber-bearing species of Solanum in order to identify selection criteria in breeding for frost resistance in potato Palisade thickness and palisade proportion showed a significant negative correlation with frost injury Path-coefficient analysis revealed that palisade thickness had the highest direct negative effect on frost injury whereas leaf thickness, not conforming to its behaviour as found in simple correlation analysis, emerged ax the next highest factor to have direct positive effect on frost injury. Direct and indirect effects of these factors on frost injury vis a vis their interdependence were found to be in support ot the ‘palisade thickness method’ for screening frost resistant genotypes in potato breeding programmes. 相似文献
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Vrinda Ramakrishnan Bijinu Balakrishnan Amit Kumar Rai Bhaskar Narayan Prakash M Halami 《International Aquatic Research》2012,4(1):1-14
Enterococci are widely distributed in the environment ranging from foods to humans and are gaining industrial importance due to their technological traits. In the present study, enterococci (Enterococcus faecium NCIM5363 (EF-63) and Enterococcus durans NCIM5427 (ED-27)) which are native to fish processing waste with an ability to produce lipase, protease and enterocin concomitantly were characterised. Lipase assay was performed by titrimetry and protease activity and was estimated using haemoglobin and casein as substrates in the presence of buffers at acidic, basic and neutral pH. Furthermore, enterocin produced by the isolates was characterised. Enterocin was also checked for its stability at different pH, temperature and proteolytic enzymes. Lipase production was found to be 22 and 10 U/ml in the absence of tributryin and increased to 40 and 24 U/ml in its presence for EF-63 and ED-27, respectively, indicating that the lipase produced is substrate dependent. Protease production was confirmed by protease assay, and the protease produced showed more affinity towards the acidic substrate. Enterocin produced was stable at low pH (2 to 3) and high temperature (121°C, 15 min) and had a molecular weight of approximately 6 kDa. It exhibited antibacterial activity against both Gram-positive and Gram-negative food-borne pathogens. Proteinase K inactivated enterocin completely, whereas trypsin did not. Novelty of this work lies in the immense industrial importance these cultures hold as they are capable of producing lipase, protease and enterocin apart from being useful in recovering proteins and lipids from fish processing wastes. 相似文献
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Summary The reduction in growth in the dark of leaf dises floated over polyethylene glycol 6000 solution of water potential −0.4 MPa,
relative to the growth of similar leaf dises floated over water for the same period, varied in the range 10–87% in 28 genotypes.
The growth reductions in the genotypes tested were in general agreement with what is known about their drought resistance.
Publication No. 906, Central Potato Research Institute, Simla. 相似文献
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Makesh Marappan Aathithya Rengarajan Venkata Satyanarayana Nallala Krishna Sukumaran Aritra Bera Thirugnamurty Sivaramakrishnan Govindarajan Thiagarajan Muniyandi Kailasam Vijayan Koyadan Kizhakedath 《Journal of fish diseases》2019,42(2):249-256
Viral nervous necrosis (VNN) affects more than 120 species mostly belonging to the order Perciformes. However, none of the brackishwater species belonging to the family Cichlidae under the order Perciformes are reported to be susceptible. Hence, the present experiment was undertaken to study the susceptibility of the brackishwater cichlid, pearlspot, Etroplus suratensis to NNV. Thirty‐day‐old pearlspot larvae were infected with NNV by immersion. Mortality was recorded till 14 days post‐infection, and the infected larvae were subjected to nested RT‐PCR and histology. The virus was isolated from infected larvae using SSN‐1 cells. To study the replication of the virus in vitro, primary cultured brain cells of E. suratensis and IEK cells were infected with NNV. No mortality was observed in any of the control or experimentally infected larvae. However, the experimentally infected larvae were positive for NNV by nested RT‐PCR and the virus was isolated using SSN‐1 cells. Further, the infected pearlspot brain cells and IEK cells showed cytopathic effect at second and third passage of the virus and they were positive for NNV by nested RT‐PCR. Pearlspot is relatively resistant to VNN although the virus could replicate in the larvae and in cell culture. 相似文献
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Ramamoorthy Saraswathy Moturi Muralidhar Das Sanjoy Periyamuthu Kumararaja Sukumaran Suvana Natarajan Lalitha Vinaya Kumar Katneni Arunachalam Nagavel Koyadan Kizhakedath Vijayan 《Aquaculture Research》2019,50(4):1096-1106
The health of the pond environment in shrimp farming is important for sustainable and profitable aquaculture, in which sediment–water interface is the most important influencing area. With this objective, the key parameters of water and sediment at the interface was studied in shrimp ponds with varying salinities and compared with the surface water and soil to understand the variations and the underlying causes. Total ammonia nitrogen and total alkalinity were higher in water at the interface as compared to surface water, whereas pH, nitrite, oxide forms of nitrogen (NO3), phosphorus (PO4) and oxidizing bacteria were observed to be lower. There was no significant difference with respect to macrominerals such as sodium, potassium, calcium and magnesium between water at the interface and surface. These changes are profoundly influenced by the uppermost 1.0‐cm thick sediment layer, where the maximum transition of nutrients takes place with the water column. The outcome of the study highlights the effectiveness of water sampling for metabolites at the interface, which reflects at an early stage any potential deterioration of pond environment, which will help the farmer to initiate timely mitigation measures. 相似文献
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John Samuel Godwin Christopher Arunachalam Ganesan Murugesan Natarajapillai Sukumaran 《Aquaculture Research》2010,42(1):129-138
This study reports the results on induced meiotic diploid gynogenesis and female homogametic nature in the Indian catfish, Heteropneustes fossilis. The eggs of H. fossilis were inseminated with conspecific sperm. The sperm suspension was diluted to 1 × 107 sperm mL−1 in Hanks balanced salt solution. Sperm were irradiated under UV light, with the exposure time ranging from 15 to 360 s (7500 ergs mm−2 for 60 s). The genetic inactivation of paternal chromosomes was confirmed by chromosome counting from the larval cells and the larvae also had a characteristic haploid syndrome. A typical ‘Hertwig effect’ in the yield of hatched larvae was observed with doses of UV exposure >75 s (9375 ergs mm2). Larvae resulting from sperm UV irradiated above 120 s (15 000 ergs mm2) were 100% haploids. Application of heat shock to the activated eggs was effective in suppressing the release of the second polar body (meiotic gynogenesis) and resulted in diploid gynogenetic larvae morphologically identical to those of the control. The best yield of diploid gynogens (49.3% with respect to the control) was found to be at 6 min after egg activation and the heat shock at 41 °C for a 1-min duration, at an ambient water temperature of 27 °C. A total of 113 diploid gynogenetic fry from seven different female fish were reared and subjected to sexing. All gynogenetic fish were female in contrast to the control, which had a mean sex ratio of 56.7% females (which was not significantly different from 50% female). From these results, the sex determination mechanism in H. fossilis was presumed to be female homogamety. 相似文献
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Krishna Sukumaran Asim K. Pal Narottam P. Sahu Shrinivas Jahageerdar Deepak Khambadakone Dipesh Debnath 《Aquaculture International》2011,19(4):749-763
The present study was conducted to investigate the changes in mineralization and morphology in response to graded levels of
dietary phosphorus in Indian major carp, Catla (Catla catla) fingerlings (av. wt. 4.23 ± 0.87 g). The experimental system constituted of 24 150-L capacity plastic tanks (eight treatments,
three replicates) stocked with 20 fingerlings each. Eight isonitrogenous and isocaloric semi-purified diets (crude protein
35%, crude lipid 8.5%) were formulated with graded levels of phosphorus (0%-control; 0.1; 0.3; 0.5; 0.7; 0.9; 1.1; 1.3; 1.5%)
using KH2PO4. The fish were fed twice daily with the respective feeds for a period of 120 days. The percentage of ash content in whole
body, vertebrae and opercular bones was found to be significantly (P < 0.05) lower in fish fed low levels of dietary phosphorus (T1, T2) in comparison with other treatments. The concentration of phosphorus and calcium was found to be significantly (P < 0.05) lower in whole body, vertebrae and opercula of fish fed low phosphorus diets (T1, T2) relative to treatments with higher levels of dietary phosphorus supplementation. The concentration of magnesium in opercular
and vertebral tissues of T1 group was significantly (P < 0.05) lower than all other groups. The X-ray radiographs did not reveal any skeletal deformities in any of the treatments.
Truss analysis showed absence of significant morphological variations between fish of different treatments. The deficiency
of dietary phosphorus in catla led to significantly lower mineralization of whole body and bone tissues, but the deficiency
was not severe enough to cause skeletal deformities and morphological changes in the fish. 相似文献