Grapevine leafroll-associated virus 1 occurs as genetically diverse populations     

Alabi OJ  Al Rwahnih M  Karthikeyan G  Poojari S  Fuchs M  Rowhani A  Naidu RA 《Phytopathology》2011,101(12):1446-1456

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The conjunctive use of compost tea and inorganic fertiliser on the growth,yield and terpenoid content of Centella asiatica (L.) urban     

Yasmeen Siddiqui  Tajul M. Islam  Yuvarani Naidu  Sariah Meon 《Scientia Horticulturae》2011

The conjunctive use of a compost tea (CT) and an inorganic fertiliser (NPK) on the growth, yield and terpenoid content of Centella asiatica (L.) urban was evaluated. CT and NPK applied at half the recommended concentration resulted in the significant enhancement of vegetative growth, yield and antioxidant content. The synergistic effect of CT₅₀ and NPK₅₀ was highly pronounced on the bioactive components Asiatic acid, madecassoside and asiaticoside. The distribution of the total antioxidants was highest in roots (80%), followed by leaves (66%) and petioles (54%). There was a strong positive correlation (r = 0.990) between fertility and total antioxidant content, suggesting an enhanced synthesis of bioactive components resulting from the treatment. This response by C. asiatica to the integrated experimental treatment suggests a viable option for the commercial cultivation of the herb. Augmenting the vegetative biomass production and bioactive components will increase the availability of this medicinal herb for the treatment of various human ailments.  相似文献   

DDT Resistance and Transformation by Different Microbial Strains Isolated from DDT-Contaminated Soils and Compost Materials     

D. Kantachote  I. Singleton  N. McClure  R. Naidu  M. Megharaj  B. D. Harch 《Compost science & utilization》2013,21(4):300-310

Bioremediation is a potential option to treat 1, 1, 1-trichloro-2, 2-bis (4-chlorophenyl) ethane (DDT) contaminated sites. In areas where suitable microbes are not present, the use of DDT resistant microbial inoculants may be necessary. It is vital that such inoculants do not produce recalcitrant breakdown products e.g. 1, 1-dichloro-2, 2-bis (4-chlorophenyl) ethylene (DDE). Therefore, this work aimed to screen DDT-contaminated soil and compost materials for the presence of DDT-resistant microbes for use as potential inoculants. Four compost amended soils, contaminated with different concentrations of DDT, were used to isolate DDT-resistant microbes in media containing 150 mg l^?1 DDT at three temperatures (25, 37 and 55°C). In all soils, bacteria were more sensitive to DDT than actinomycetes and fungi. Bacteria isolated at 55°C from any source were the most DDT sensitive. However DDT-resistant bacterial strains showed more promise in degrading DDT than isolated fungal strains, as 1, 1-dichloro 2, 2-bis (4-chlorophenyl) ethane (DDD) was a major bacterial transformation product, while fungi tended to produce more DDE. Further studies on selected bacterial isolates found that the most promising bacterial strain (Bacillus sp. BHD-4) could remove 51% of DDT from liquid culture after 7 days growth. Of the amount transformed, 6% was found as DDD and 3% as DDE suggesting that further transformation of DDT and its metabolites occurred.  相似文献   

Bioremediation of Arsenic-Contaminated Water: Recent Advances and Future Prospects     

Md Mezbaul Bahar  Mallavarapu Megharaj  Ravi Naidu 《Water, air, and soil pollution》2013,224(12):1-20

Arsenic contamination of groundwater and surface water is widespread throughout the world. Considering its carcinogenicity and toxicity to human and animal health, remediation of arsenic-contaminated water has become a high priority. There are several physicochemical-based conventional technologies available for removing arsenic from water. However, these technologies possess a number of limitations such as high cost and generation of toxic by-products, etc. Therefore, research on new sustainable and cost-effective arsenic removal technologies for water has recently become an area of intense research activity. Bioremediation technology offers great potential for possible future application in decontamination of pollutants from the natural environment. It is not only environmentally friendly but cost-effective as well. This review focuses on the state-of-art knowledge of currently available arsenic remediation methods, their prospects, and recent advances with particular emphasis on bioremediation strategies.  相似文献   

The effects of ultraviolet-B radiation on photosynthesis of different aged needles in field-grown loblolly pine     

Naidu SL  Sullivan JH  Teramura AH  DeLucia EH 《Tree physiology》1993,12(2):151-162

We examined the effect of supplemental UV-B radiation (290-320 nm) on photosynthetic characteristics of different aged needles of 3-year-old, field-grown loblolly pine (Pinus taeda L.). Needles in four age classes were examined: I, most recently fully expanded, year 3; II, first flush, year 3; III, final flush, year 2; and IV, oldest needles still present, year 2. Enhanced UV-B radiation caused a statistically significant decrease (6%) in the ratio of variable to maximum fluorescence (F(v)/F(m)) following dark adaptation only in needles from the youngest age class, suggesting transient damage to photosynthesis. However, no effects of enhanced UV-B radiation on other instantaneous measures of photosynthesis, including maximum photosynthesis, apparent quantum yield and dark respiration, were seen for needles of any age. Foliar nitrogen concentration was unaffected by UV-B treatment. However, the (13)C/(12)C carbon isotope ratios (delta(13)C-a time integrated measure of photosynthetic function) of needles in age classes II and IV were 3% (P < 0.01) and 2% (P < 0.05) more negative, respectively, in treated plants than in control plants. Exposure to enhanced UV-B radiation caused a 20% decrease in total biomass and a 4% (P < 0.05), 25% (P < 0.01), and 9% (P < 0.01) decrease in needle length of needles in age classes I, II, and IV, respectively. The observed decreases in delta(13)C, and F(v)/F(m) of the needles in the youngest needle age class suggest subtle damage to photosynthesis, although overall growth reductions were probably a result of decreased total leaf surface rather than decreased photosynthetic capacity. Needles of age class IV had lower light- and CO(2)-saturated maximum photosynthetic rates (39%), lower dark respiration (34%), lower light saturation points (37%), lower foliar nitrogen concentration (28%), and lower delta(13)C (14%) values than needles of age class I. Apparent quantum yield and F(v)/F(m) did not change with needle age. The observed changes in photosynthesis and foliage chemical composition with needle age are consistent with previous studies of coniferous trees and may represent adaptations of older needles to shaded conditions within the canopy.  相似文献   

Molecular characterization of chromium (VI) reducing potential in Gram positive bacteria isolated from contaminated sites     

Ramesh C. Patra  Seidu Malik  Michael Beer  Mallavarapu Megharaj  Ravi Naidu 《Soil biology & biochemistry》2010,42(10):1857-1863

Hexavalent chromium [Cr(VI)] is highly toxic, teratogenic and carcinogenic to man and other animals. Some bacterial species have the ability to reduce Cr(VI) to a stable speciation state of trivalent chromium [Cr(III)], which is insoluble and comparatively less toxic. Therefore, the reduction of Cr(VI) thus provides potential as a means for environmental bioremediation of Cr(VI) pollution. In the present study bacteria isolated from chromium and diesel contaminated sites were found to have the ability to rapidly reduce highly toxic concentrations of Cr(VI) to Cr(III) when grown in minimal medium supplemented with glucose as the sole carbon source. Partial chromate reductase gene sequences were retrieved after PCR amplification of genomic DNA extracted from three Gram positive isolates which were highly similar (>99% sequence similarity) to chromate reductase genes found in Gram negative bacteria, more specifically those identified from Escherichia coli and Shigella spp. whole-genome studies. The isolated bacteria were putatively identified by 16S rRNA gene sequencing as Arthrobacter aurescens strain MM10, Bacillus atrophaeus strain MM20, and Rhodococcus erythropolis strain MM30.  相似文献   

Blood cholinesterase activity of some Indian breeds of sheep     

N V Naidu  A Janardhan 《Research in veterinary science》1971,12(1):93-94

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RELATIVE EFFICACY OF TWO ARTIFICIAL SUBSTRATES IN THE COLLECTION OF SEA SCALLOP (Placopecten magellanicus) SPAT     

K. S. Naidu  F. M. Cahill  D. B. Lewis 《Journal of the World Aquaculture Society》1981,12(2):163-171

Relative efficacy of two substrates commonly employed for procuring scallop spat is described. Monofilament gillnetting was superior to flexible polyethylene insofar as collecting greater numbers of sea scallops was concerned. Overlapping in sheet polyethylene resulted in rapid substrate saturation thus reducing substrate surface for larval attachment.  相似文献   

Characterization of a vector-non-transmissible isolate of Tomato spotted wilt virus     

R. A. Naidu  J. L. Sherwood  C. M. Deom 《Plant pathology》2008,57(1):190-200

The characteristics of a thrips‐non‐transmissible isolate of Tomato spotted wilt virus (TSWV), designated TSWV‐M, were compared with those of a thrips‐transmissible isolate, designated TSWV‐T. TSWV‐M showed a narrower host range than TSWV‐T. Adult thrips failed to transmit TSWV‐M, although the vector acquired the virus during the larval stages. TSWV‐M was detected by RT‐PCR in adult thrips bodies, but not in thrips heads, suggesting that loss of thrips transmissibility was the result of the absence of virus in adult thrips salivary glands. Whereas N (nucleoprotein), NSs (non‐structural protein) and G_C (the C‐terminal portion of the glycoprotein precursor protein) were present in similar amounts in leaf tissue from TSWV‐M‐ or TSWV‐T‐infected plants, G_N (the N‐terminal portion of the glycoprotein precursor protein) was present at much lower amounts in TSWV‐M‐ than in TSWV‐T‐infected plants. SDS‐PAGE and immunoblotting analysis of TSWV‐M and TSWV‐T virion preparations with G_N‐ and G_C‐specific antibodies revealed similar amounts of the G_N and G_C glycoproteins in TSWV‐T virions, but lower amounts of G_N than G_C in TSWV‐M virions. This resulted in a statistically significant reduction in the G_N/G_C ratio in TSWV‐M virions. In affinoblots, the G_C and G_N glycoproteins of TSWV‐M exhibited weak binding with lectins showing affinity for N‐linked oligosaccharide structures. Sequence analysis of M RNA (medium segment of the TSMV genome) revealed no deletions or frameshift mutations in the G_N/G_C precursor of TSWV‐M. However, five amino acid changes were detected in the G_N/G_C precursor. A single, relatively conservative amino acid substitution (V→I) was observed in the NSm protein. Sequence analysis of S RNA (small portion of the TSMV genome) revealed a large intergenic region with no changes in the N protein and with three amino acid changes in the NSs protein.  相似文献   

Inheritance of iron deficiency chlorosis resistance in groundnut (Arachis hypogaea L.)     

Santosh K. Pattanashetti  Gopalakrishna K. Naidu  Prakyath Kumar K.V.  Omprakash Kumar Singh  Basavaraj D. Biradar 《Journal of plant nutrition》2018,41(3):321-329

Iron-deficiency chlorosis (IDC) is an important abiotic constraint affecting the growth and yield of groundnut in calcareous and alkaline soils worldwide. The present study investigated the inheritance of IDC resistance among four straight crosses of groundnut involving four IDC susceptible cultivars as females and a common IDC resistant male parent. The F₁'s of all the four crosses were resistant to IDC indicating the dominant nature of IDC resistance. The F₂'s of all the four crosses showed a good fit to the ratio of 15 (IDC resistant): 1 (IDC susceptible) and their behavior among the F₃'s was as per the expected ratio of 7:4:4:1. The IDC resistance in groundnut is under the control of duplicate dominant genes wherein, the presence of a dominant allele at either of the loci results in IDC resistance, while duplicate recessive results in IDC susceptibility. This information would facilitate development of IDC resistant cultivars of groundnut.  相似文献