排序方式： 共有53条查询结果，搜索用时 15 毫秒
31.
Maria John Muthaiya Praveen Nagella Muthu Thiruvengadam AbulKalam Azad Mandal 《Journal of Crop Science and Biotechnology》2013,16(2):143-149
Tea cell suspension culture is an alternative method for the synthesis of secondary metabolites. For the separation of cells, different concentrations of pectinase were used and a concentration of 0.5% was found to be the optimum concentration for the separation of cells (41.7%) in the culture medium than the other two concentrations (33.3 and 25.0%). The separated cells were cultured in liquid MS medium using different PGR combinations. The time taken for the cells to reach stationary phase, under different PGRs, ranged from 17 to 21 d. The maximum cell density was found in IAA and 2, 4-D medium at 21 d followed by 2, 4-D. Results revealed that the amount of secondary metabolites such as catechins were high with stationary phase when compared to other growth phases (lag and log phases). Different concentrations of shikimic acid (10, 20, and 30 mM) were added to the stationary phase of cell culture in the bioreactor and the secondary metabolite content was analyzed. Synthesis of polyphenols, catechins, caffeine, and other secondary components were high (33.87, 22.85, and 4.66%) with 20 mM shikimic acid treatment than the other two concentrations. 相似文献
32.
Mohd. Masood Hussain Nageswara Rao Amanchi Venkata Ramanaiah Solanki Mohan Bhagavathi 《Pesticide biochemistry and physiology》2008,90(1):66-70
One of the major changes that have occurred over the past few years is the re-examination of conventional methods and the global demand for innovative low cost bioassay tests for assessing water quality, toxicity evaluation and bioremediation. In the present study acute toxicity, physiological and cytotoxic impact of carbofuran to a commonly occurring fresh water ciliate was measured. Intrinsic cytotoxicity was evident on macro nuclear apparatus that exhibited deformities such as fragmentation, deep incision, vacuolization and degenerative macronucleus. Depletion in the food vacuole formation of Paramecia was evident. Changes in the pulsatory vacuole activity of Paramecium caudatum, highlighted dose dependent response by the test compound. The simplicity of handling this ciliate makes unicellular eukaryote, an alternative organism for the toxicity assessment of pollutants. The tests carried in this study are simple and fast, a bioassay that gives overall information about the physiological and cytotoxic effects of carbofuran to P. caudatum. Such bioassay tests using ciliates are more suitable for risk assessment of water quality, early detection of water pollution and possible role of ciliates as bioindicators and strategic tools in the bioremediation of water bodies. 相似文献
33.
Nalini Kumari N Ramana Reddy Y Blummel M Nagalakshmi D Sudhakar K Ravinder Reddy V Monika T Pavani M Sudhakara Reddy M Reddy BV Ravinder Reddy C 《Tropical animal health and production》2012,44(7):1717-1724
An experiment was conducted to study the effect of roughage to the concentrate ratio of complete diets containing sweet sorghum bagasse (SSB), an agro-industrial by product, as sole roughage source on nutrient utilization in ram lambs. Twenty-four Nellore × Deccani cross ram lambs aged about 3?months (average body wt. 10.62?±?0.03?kg) were randomly allotted into four groups fed with CR-I (60R:40C), CR-II (50R:50C), CR-III (40R:60C), and CR-IV (30R:70C) complete diets. The roughage to concentrate ratio did not affect the dry matter intake (in grams/day or grams/kilogram weight(0.75)). The crude protein (P?相似文献
34.
P. Srinivasa Rao K. V. N. Suresh Reddy S. Kalyani A. Krishnaiah 《Wood Science and Technology》2007,41(5):427-442
This study investigates the potential use of neem (Azadirachta indica) sawdust treated with hydrochloric acid for the removal of copper (II) and nickel (II) ions from wastewater. The effects
of different system variables, viz, adsorbent dosage, initial metal ion concentration, pH and contact time were studied. The
results showed that as the amount of the adsorbent was increased, the percentage of metal ion removal increased accordingly.
Optimum pH value for metal adsorption is determined as 5.0 for Cu (II) and 4.0 for Ni (II) ions. Maximum metal is sequestered
in 150 min for Cu (II) and 180 min for Ni (II) after the beginning of every experiment. Similar experiments were carried out
with acid treated sawdust to compare the results. The adsorption of metal ions followed a first order rate equation. Both
Freundlich and Langmuir adsorption models are suitable for describing the sorption of Cu (II) and Ni (II) on the two forms
of sawdust. Furthermore, the natural organic matter (neem sawdust) is characterized by FTIR spectra and surface area analysis.
At optimal conditions the maximum adsorption capacity is found to be 48.3 and 286 mg/g for Cu (II) and 31.5 and 74.1 mg/g
for Ni (II) in natural and acid treated forms, respectively. 相似文献
35.
36.
37.
Venkata?S.?S.?R.?Marella Paula?Roberts Paul?W.?Hill Davey?L.?JonesEmail author 《Biology and Fertility of Soils》2017,53(4):369-374
Here, we investigated how root age and mode of death influenced their subsequent turnover and rate of C loss from soil. Young white-coloured and older pigmented roots of Cistus monspeliensis were excised (to simulate death by mechanical severance) or frozen (to simulate death by cell rupture) and immediately buried in soil. CO2 loss from soil was then measured over time. In a parallel experiment, the rate of CO2 loss from severed or ruptured roots in the absence of soil was determined. Our results revealed large differences in root chemistry related to age, with young roots having a lower C:N ratio and a greater nutrient content (soluble C, N, P and K). Both root age and mode of death resulted in very different temporal patterns of C release from soil. The amount of C lost from soil followed the series: severed white roots (42.6 ± 3.3 mg C) > ruptured pigmented roots (27.7 ± 0.4 mg C) = ruptured white roots (27.1 ± 0.5 mg C) > severed pigmented roots (10.1 ± 1.0 mg C) > soil only (3.0 ± 0.2 mg C). Therefore, depending on the treatment, 7 to 41% of the total root-derived C was lost as CO2 over the duration of the experiment. Comparison with soil-free treatments revealed that the CO2 release from the severed roots buried in soil was not associated with microbial breakdown but caused by root-induced autophagy in an attempt to keep themselves metabolically active. Ruptured roots also induced a rapid loss of CO2 which we ascribe to the diffusive loss of root solutes into the soil and subsequent microbial mineralization. Surprisingly, the rate of C loss from soil was greater from the severed root tips than those that were ruptured. Our results imply two distinct routes of C loss dependent on how roots die, one which bypasses the microbial community and one which flows through it. 相似文献
38.
Arjuna Rao Palakollu Venkata Panda Kusuma Kumari Tavva Surya Santosh Mohan Dev Muktinutalapati Venkata Subba Rao Vangury Manga 《Journal of Crop Science and Biotechnology》2012,15(3):195-203
Genetic analysis of sodium and sodium/potassium (Na/K) ratios in leaf and stem was carried out through diallel analysis involving two tolerant, one moderately tolerant, and two sensitive genotypes as parents. Three-week-old seedlings were subjected to a critical level of salinization (17 decisiemens per meter of electrical conductivity). Leaf and stem sampling (from 5 parents and 20 hybrids arranged in a randomized block design with three replications of 10 each) was done 30 days after salinization when susceptible parents were severely effected. Predominance of non-additive gene action for stem sodium and dominance component for leaf Na/K were noticed while both additive and non-additive components played a significant role for stem Na/K. A single group of genes seems to be operative for these characters. Hybrids produced by crossing the two sensitive parents were tolerant suggesting genetic complementation and involvement of different loci in the two parents for salinity tolerance. The overall dominant nature of tolerance and the additive gene action for these salinity related characters suggested the possibility of breeding pearl millet lines through hybridization and selection to pyramid the favorable genes. 相似文献
39.
Shujauddin Mohammed Rajkumar Hemalatha Syed Shah Yousuf Hussain Qadri Vure Venkata Annapurna 《Journal of animal physiology and animal nutrition》2019,103(2):687-694
Semi‐synthetic diets (SSD) are recommended and are widely used to carry out experiments in rodents. However, in our experiments planned to carry out generation studies in female Golden Syrian hamsters using semi‐synthetic diets, it was observed that the hamsters did not conceive as a result of decreased food intake. In this paper, we present the effects of both semi‐synthetic diets and natural source diets (NSD) on food intake, body weight and reproductive performance of this species. Four‐week‐old female hamsters were equally divided into 3 groups and initially acclimatized for 2 weeks on natural chow diet (NCD). Thereafter, they were fed either control diet, high fat diet (HFD) or low protein diet (LPD) based on semi‐synthetic/natural source ingredients until 12 weeks. Daily food intake and weekly body weights were monitored. Hamsters were kept for mating for about 2 weeks from 10th week onwards, during which the pregnancy confirmation test was done using standard vaginal smear examination. In all the groups fed SSD, the food intake was very poor, hamsters lost body weight and did not conceive, thus preventing us from carrying out further experiments. Hamsters fed NCD/NSD ingested more than twice as much as hamsters fed SSD (7–8 g/day/hamster against 3 g/day/hamster on average respectively). Based on the results of the current research, we conclude that the routinely used semi‐synthetic diet is not suitable for carrying out studies in female hamsters. We suggest that scientists must also consider the unusual biological characteristics of a given species besides other biological factors. It is therefore critical to select appropriate biological models and diets that provide optimal sensitivity and specificity to accomplish the research objectives. 相似文献
40.
Venkata Ramana Vollala Subramanya Upadhya Satheesha Nayak 《Journal of Veterinary Behavior: Clinical Applications and Research》2010,5(2):69-74
Extracts of Bacopa monniera (Brahmi, BM), a traditional ayurvedic medicine, have been reported to have memory-enhancing effects in animals. However, there are no studies in which different dosages or chronic use have been explored. The current study examined the effects of standardized extract of BM on behavioral changes of Wistar rats when administered the extract for various durations and in varying doses. We divided the animals into 2-, 4-, and 6-week treatment groups. Rats in each of these groups were divided into 20 mg/kg, 40 mg/kg, and 80 mg/kg dose groups (n = 8 for each dose). After the treatment period, the rats, along with age-matched normal and gum acacia control rats, were subjected to spatial learning (T-maze) and passive avoidance tests. The data were compared with those of age-matched control rats. The study was conducted at the Melaka Manipal Medical College, Manipal University, Manipal, Karnataka, India. The results showed improvement in spatial learning performance and enhanced memory retention in rats treated with BM extract. These results clearly indicate that oral administration of BM extract improved learning and memory in rats. 相似文献