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1.
R. Pathirana 《Plant Breeding》1992,108(4):314-319
Due to the non-availability of sources of resistance in Sri Lanka to Phytopbthora blight in sesame (Sesamum indicum) caused by Phytopbthora nicotianae var. parasitica, a mutation breeding programme was initiated. Seeds of three genotypes were subjected to six doses of gamma rays from 100 Gy to 750 Gy from a 60Co source. Seeds of M2 bulks, sampled by variety and treatment from the first five capsules formed on M1 plants, were grown in a field with a history of repeated incidence of the disease. The best 21 lines, having the highest survival and seed production, identified in the screening of M3 and M4 progeny rows of selected M2 single plants were then tested in a replicated field trial with the recommended cultivar ‘MI 3’ as a control. The plant survival in selected lines averaged 43.3 percent as against 7.2 percent in the recommended variety. Eight selections recorded significantly higher seed yield than ‘MI 3’ at P < 0.01 and another three at P < 0.05. Gamma ray treatments of 450 Gy and 600 Gy produced more lines tolerant to the disease than the other doses used. 相似文献
2.
Sandeep?KumarEmail author Ranjith?P.?Udawatta Stephen?H.?Anderson Ashish?Mudgal 《Agroforestry Systems》2011,83(1):51-62
Buffers have been found to reduce non-point source pollution (NPSP) from watersheds. Hydrologic simulation models assist in
predicting the effects of buffers on runoff and sediment losses from small watersheds. The objective of this study was to
calibrate, validate and simulate runoff and sediment losses and compare buffer effects on NPSP losses relative to control
watersheds (no buffer) for seven years. The experimental design consists of four watersheds under pasture management which
were monitored from 2002 through 2008; two with agroforestry buffers (AgB 100 and AgB 300) and two control watersheds (CW
400 and CW 600). Pasture areas included red clover (Trifolium pretense L.) and lespedeza (Kummerowia stipulacea Maxim.) planted into fescue (Festuca arundinacea Schreb.) while the agroforestry buffer area included Eastern cottonwood trees (Populus deltoids Bortr. ex Marsh.) planted into fescue. The APEX model was calibrated from 2002 to 2005 and was validated from 2006 to 2008.
The r
2
and NSE values for the calibration and validation periods of the runoff varied from 0.52 to 0.78 and 0.50 to 0.74, respectively.
The model did not predict sediment loss very well probably due to insufficient number of measured events and low measured
sediment loss. The measured runoff was 57% higher for CW watersheds compared to AgB watersheds. The measured sediment loss
was 95% higher for CW watersheds compared to AgB watersheds. After calibrating and validating the model, it was run for long-term
scenario analyses for 10 years from 1999 to 2008. Simulated buffer width had a significant influence on runoff. Simulated
runoff decreased by 24% when the buffer width was doubled compared to losses associated with the measured buffer width. Simulated
runoff from the CW watersheds was 11% higher with double stocking density (relative to measured density) compared to AgB watersheds
with double stocking density. With half stocking density (relative to measured density), the AgB watershed had 18% lower runoff
compared to CW. Results from this study imply that establishment of agroforestry buffers on grazed pasture watersheds reduce
runoff and sediment losses compared to control watersheds without buffers. 相似文献
3.
HNKS Pathirana Gee-Wook Shin SHMP Wimalasena BCJ De Silva Sabrina Hossain Gang-Joon Heo 《Journal of Exotic Pet Medicine》2018,27(4):67-73
Proteus spp. are widely recognized as opportunistic pathogens causing urinary tract and septic infections in humans and animals. The aim of this study was to investigate the prevalence of plasmid-mediated quinolone resistance genes and mutations in the quinolone resistance determining region in association with the detection of quinolone susceptibility of 24 strains of pet turtle-borne Proteus spp. Susceptibility of 4 antimicrobials including nalidixic acid, ciprofloxacin, ofloxacin, and levofloxacin was examined by disk diffusion and minimum inhibitory concentration test. Six isolates were resistant to nalidixic acid showing either intermediate resistance or resistance to other quinolones. All nalidixic acid, resistant isolates harbored mutations in gyrB (N440T/A401G/Q411S). Two of the isolates had both gyrA (S83I) and parC (S80I) mutations. Twenty-one isolates were positive for the presence of plasmid-mediated quinolone resistance genes; the qnrD gene had the highest prevalence with 19 (79.2%), while qnrS, qnrA, qnrB, and aac(6′), Ib-cr genes were present in 9 (37.5%), 2 (8.3%), 1 (4.2%), and 11 (45.8%) isolates, respectively. These results suggest that pet turtle-associated Proteus spp. should be considered a potential source of antimicrobial resistance determinants. 相似文献
4.
5.
Jamseel Moopantakath Madangchanok Imchen Ranjith Kumavath Rosa María Martínez-Espinosa 《Marine drugs》2021,19(8)
This study presents a comparative analysis of halophiles from the global open sea and coastal biosystems through shotgun metagenomes (n = 209) retrieved from public repositories. The open sea was significantly enriched with Prochlorococcus and Candidatus pelagibacter. Meanwhile, coastal biosystems were dominated by Marinobacter and Alcanivorax. Halophilic archaea Haloarcula and Haloquandratum, predominant in the coastal biosystem, were significantly (p < 0.05) enriched in coastal biosystems compared to the open sea. Analysis of whole genomes (n = 23,540), retrieved from EzBioCloud, detected crtI in 64.66% of genomes, while cruF was observed in 1.69% Bacteria and 40.75% Archaea. We further confirmed the viability and carotenoid pigment production by pure culture isolation (n = 1351) of extreme halophiles from sediments (n = 410 × 3) sampling at the Arabian coastline of India. All red-pigmented isolates were represented exclusively by Haloferax, resistant to saturated NaCl (6 M), and had >60% G + C content. Multidrug resistance to tetracycline, gentamicin, ampicillin, and chloramphenicol were also observed. Our study showed that coastal biosystems could be more suited for bioprospection of halophiles rather than the open sea. 相似文献
6.
Bei Chu Keith W. Goyne Stephen H. Anderson Chung-Ho Lin Ranjith P. Udawatta 《Agroforestry Systems》2010,79(1):67-80
The potential of veterinary antibiotics (VAs) to impact human and environmental health requires the development and evaluation
of land management practices that mitigate VA loss from manure-treated agroecosystems. Vegetative buffer strips (VBS) are
postulated to be one management tool that can reduce VA transport to surface water resources. The objectives of this study
were to (1) investigate oxytetracycline (OTC) and sulfadimethoxine (SDT) sorption to agroforestry buffer, grass buffer, and
cropland soils, (2) evaluate differences in VA sorption to soils collected from different vegetative management and soil series,
and (3) elucidate relationships between soil properties and VA sorption. Sorption/extraction isotherms for OTC were well-fitted
by the Freundlich isotherm model (r
2 > 0.86). OTC was strongly adsorbed by all soils and the VA was not readily extractable. OTC and SDT solid to solution partition
coefficients (K
d) values are significantly greater for soils planted to VBS relative to grain crops. Significant differences in OTC and SDT
K
d values were also noted among the soil series studied. Linear regression analyses indicate that clay content and pH were the
most important soil properties controlling OTC and SDT adsorption, respectively. Results from this study suggest that agroforestry
and grass buffer strips may effectively mitigate antibiotic loss from agroecosystems, in part, due to enhanced antibiotic
sorption properties. 相似文献
7.
Brummell DA Watson LM Pathirana R Joyce NI West PJ Hunter DA McKenzie MJ 《Journal of agricultural and food chemistry》2011,59(20):10987-10994
Methylselenocysteine (MeSeCys) is an amino acid derivative that possesses potent anticancer activity in animals. Plants that can tolerate growth on soils with high Se content, known as Se hyperaccumulators, do so by converting inorganic Se to MeSeCys by the enzyme selenocysteine methyltransferase (SMT). A cDNA encoding the SMT from a Se hyperaccumulator was overexpressed in tomato (Solanum lycopersicum). Transgenic plants were provided with selenite or selenate to the roots during fruit development, and liquid chromatography-mass spectrometry was used to show that MeSeCys accumulated in the fruit but not in the leaves. Depending on the transgenic line and Se treatment, up to 16% of the total Se in the fruit was present as MeSeCys. MeSeCys was produced more effectively from selenite on a percentage conversion basis, but greater accumulation of MeSeCys could be achieved from selenate due to its better translocation from the roots. MeSeCys was heat stable and survived processing of the fruit to tomato juice. 相似文献
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9.
Ranjith Jayaweera Richard Petersen Pavel Smejtek 《Pesticide biochemistry and physiology》1982,18(2):197-204
Pentachlorophenol (PCP) decreases the rate of carbon assimilation in the alga Selenastrum capricornutum. In parallel with the reduction of carbon assimilation in this alga there is a decrease of electrical resistance of lipid membranes and development of negative membrane surface charge. The experimental results suggest that PCP toxicity to algae is due to adsorption of negatively charged PCP ions at the membrane surface that act as carriers of hydrogen ion across the membrane. This protonophoretic action of PCP causes the decrease of membrane electrical resistance and the dissipation of hydrogen ion electrochemical potential gradients across cellular and subcellular membranes, which reduces the ability of algae to assimilate carbon. 相似文献
10.
Raja A Vignesh AR Mary BA Tirumurugaan KG Raj GD Kataria R Mishra BP Kumanan K 《Veterinary immunology and immunopathology》2011,140(3-4):252-258
This study involved cloning and sequencing of the coding regions of all 10 Toll-like receptor (TLR) genes of goat. Goat TLR 1-10 gene sequences revealed a high degree of nucleotide identity with sheep and cattle sequences (>90%) and 75-85% with pig, mouse and human sequences. At the amino acid level, 85-99% similarity was observed with sheep and cattle and 60-85% with pig, mouse and human. TLR9c DNA of goat showed the highest amino acid identity to that of sheep (99%) while TLR8 cDNA showed the lowest identity of 88.7% to that of sheep. Variations were seen in the number of leucine rich repeats (LRRs) of goat TLRs as compared to other ruminant species with maximum differences in the TLR3 gene. Phylogenetic analysis through molecular evolution and genetic analysis (MEGA) software and multi dimensional scaling revealed a high degree of conservation of goat TLRs with those from other species. However when the TIR domain of all the TLRs were compared, goat TLR7 TIR alone showed a high divergence of 19.3 as compared to sheep sequences. This is the first report of the full-length cDNA sequences of all the 10 TLR genes of goats which would be a useful tool for the study of evolutionary lineages and for phylogenetic analysis. 相似文献