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Summary Using an aeroscope, airborne fungal spores were sampled for two years, 1987–1988 at Tiruchirapalli, Tamil Nadu, India. The aerospora components, their seasonal and annual variations in incidence in the air are discussed and a spore calendar for Tiruchirapalli is presented. 相似文献
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Arumugam Velusamy Venkatesan Manigandan Ramachandran Karthik Ramachandran Saravanan Palanisamy Satheesh Kumar Sundaresan Umamaheswari 《International journal of peptide research and therapeutics》2020,26(1):201-208
International Journal of Peptide Research and Therapeutics - Marine ecosystems are unique and a largely diverse chest of natural resources which are still to be explored for new marine species.... 相似文献
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P. Gurusaravanan S. Vinoth M. Satheesh Kumar N. Thajuddin N. Jayabalan 《Journal of Genetic Engineering and Biotechnology》2013,11(1):9-16
The challenging task of bringing high efficiency transformed plants attracts lot of attention in recent times. In search for this, there have been many attempts made using, different techniques like tissue culture and plant breeding methods. Here we report a suitable alternative facile route, where cyanobacterial extracellular products are utilized as growth regulators and its performance validated on Gossypium hirsutum L. MS medium is tested with cyanobacterial extracellular products of Nostoc ellipsosporum, Dolichospermum flos-aquae and Oscillatoria acuminata .Our best results show that the addition of O. acuminata extracellular product with plant growth hormones gives the excellent induction and elongation in cotton. In addition to this, the multiple shoot was obtained on MS medium fortified with 1.0 mg L?1 BA with 8% O. acuminata and 1.5 mg L?1 TDZ with 12% O. acuminata. High frequency of shoot elongation supplemented with MS medium, iP 2.5 mg L?1 and 16% O. acuminata and root production MS medium fortified with 12% O. acuminata best responsible for regeneration in cotton plants. The rooted plants were hardened and transferred to soil with 90% survival rate. 相似文献
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Selvaraj Michael Gomez N. Manikanda Boopathi S. Satheesh Kumar T. Ramasubramanian Zhu Chengsong P. Jeyaprakash A. Senthil R. Chandra Babu 《Acta Physiologiae Plantarum》2010,32(2):355-364
Drought is a major limitation for rice production in rainfed ecosystems. Identifying quantitative trait loci (QTLs) linked
to drought resistance provides opportunity to breed high yielding rice varieties suitable for drought-prone areas. Although
considerable efforts were made in mapping QTLs associated with drought-resistance traits in rice, most of the studies involved
indica × japonica crosses and hence, the drought-resistance alleles were contributed mostly by japonica ecotypes. It is desirable to look for genetic variation within indica ecotypes adapted to target environment (TE) as the alleles from japonica ecotype may not be expressed under lowland conditions. A subset of 250 recombinant inbred lines (RILs) of F8 generation derived from two indica rice lines (IR20 and Nootripathu) with contrasting drought-resistance traits were used to map the QTLs for morpho-physiological
and plant production traits under drought stress in the field in TE. A genetic linkage map was constructed using 101 polymorphic
PCR-based markers distributed over the 12 chromosomes covering a total length of 1,529 cM in 17 linkage groups with an average
distance of 15.1 cM. Composite interval mapping analysis identified 22 QTLs, which individually explained 4.8–32.2% of the
phenotypic variation. Consistent QTLs for drought-resistance traits were detected using locally adapted indica ecotypes, which may be useful for rainfed rice improvement. 相似文献
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G. Satheesh kumar M. Subhosh Chandra K. V. Mallaiah P. Sreenivasulu Yong-Lark Choi 《Biotechnology and Bioprocess Engineering》2010,15(3):435-440
In this study, the production of extracellular thermostable α-amylase by newly isolated thermophilic Alicyclobacillus acidocaldarius was detected on LB agar plates containing 1.0% soluble potato starch and incubated at 60°C. This extracellular α-amylase
was purified to homogeneity by ammonium sulphate precipitation followed by Sephadex and ion-exchange chromatography. The α-amylase
was purified to 8.138 fold homogeneity with a final recovery of 58% and a specific activity of 3,239 U/mg proteins. The purified
α-amylase appeared as a single protein band on SDS-PAGE with a molecular mass of 94.5 kDa. Non-denaturing PAGE analysis showed
one major band associated with enzyme activity, indicating the absence of isoenzymes. A TLC analysis showed maltose as major
end product of the enzyme. The optimum assay temperature and pH for enzyme activity were 60°C and 6.0 respectively; however,
the enzyme activity was stable over a wide range of pH and temperatures. The α-amylase retained its activity in the presence
of the denaturing agents — SDS, Triton X-100, Tween-20, Tween-80, and was significantly inhibited by EDTA and urea. Calcium
ions increased the enzyme activity, while Hg2+, Zn2+, and Co2+ had inhibitory effects. The K
m and V
max values were found to be 2.9 mg/mL and 7936 U/mL respectively. 相似文献
7.
The efficacy of UV treatment to control bacterial adhesion onto hard surfaces was investigated in laboratory conditions. The major characteristics necessary for biofilm formation like extracellular polymeric substance (EPS) production, carbohydrate and protein concentration in EPS, and adhesion ability onto hard surface were studied using two bacterial strains isolated from marine biofilms. The results showed that there was a considerable difference between the control and UV treated bacterial cultures in their viability, production of EPS, and adhesion ability. The protein and carbohydrate concentration of the EPS and the adhesion of bacterial cells to surface were also considerably reduced due to UV treatment. This study indicates that treatment of water with UV light may be used to control biofilm development on hard surfaces. 相似文献
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Kothapalli S Nair S Alokam S Pang T Khakhria R Woodward D Johnson W Stocker BA Sanderson KE Liu SL 《Journal of bacteriology》2005,187(8):2638-2650
The genomes of most strains of Salmonella and Escherichia coli are highly conserved. In contrast, all 136 wild-type strains of Salmonella enterica serovar Typhi analyzed by partial digestion with I-CeuI (an endonuclease which cuts within the rrn operons) and pulsed-field gel electrophoresis and by PCR have rearrangements due to homologous recombination between the rrn operons leading to inversions and translocations. Recombination between rrn operons in culture is known to be equally frequent in S. enterica serovar Typhi and S. enterica serovar Typhimurium; thus, the recombinants in S. enterica serovar Typhi, but not those in S. enterica serovar Typhimurium, are able to survive in nature. However, even in S. enterica serovar Typhi the need for genome balance and the need for gene dosage impose limits on rearrangements. Of 100 strains of genome types 1 to 6, 72 were only 25.5 kb off genome balance (the relative lengths of the replichores during bidirectional replication from oriC to the termination of replication [Ter]), while 28 strains were less balanced (41 kb off balance), indicating that the survival of the best-balanced strains was greater. In addition, the need for appropriate gene dosage apparently selected against rearrangements which moved genes from their accustomed distance from oriC. Although rearrangements involving the seven rrn operons are very common in S. enterica serovar Typhi, other duplicated regions, such as the 25 IS200 elements, are very rarely involved in rearrangements. Large deletions and insertions in the genome are uncommon, except for deletions of Salmonella pathogenicity island 7 (usually 134 kb) from fragment I-CeuI-G and 40-kb insertions, possibly a prophage, in fragment I-CeuI-E. The phage types were determined, and the origins of the phage types appeared to be independent of the origins of the genome types. 相似文献
9.
FbpA-Dependent biosynthesis of trehalose dimycolate is required for the intrinsic multidrug resistance, cell wall structure, and colonial morphology of Mycobacterium smegmatis 下载免费PDF全文
Ligation of mycolic acids to structural components of the mycobacterial cell wall generates a hydrophobic, impermeable barrier that provides resistance to toxic compounds such as antibiotics. Secreted proteins FbpA, FbpB, and FbpC attach mycolic acids to arabinogalactan, generating mycolic acid methyl esters (MAME) or trehalose, generating alpha,alpha'-trehalose dimycolate (TDM; also called cord factor). Our studies of Mycobacterium smegmatis showed that disruption of fbpA did not affect MAME levels but resulted in a 45% reduction of TDM. The fbpA mutant displayed increased sensitivity to both front-line tuberculosis-targeted drugs as well as other broad-spectrum antibiotics widely used for antibacterial chemotherapy. The irregular, hydrophobic surface of wild-type M. smegmatis colonies became hydrophilic and smooth in the mutant. While expression of M. smegmatis fbpA restored defects of the mutant, heterologous expression of the Mycobacterium tuberculosis fbpA gene was less effective. A single mutation in the M. smegmatis FbpA esterase domain inactivated its ability to provide antibiotic resistance. These data show that production of TDM by FbpA is essential for the intrinsic antibiotic resistance and normal colonial morphology of some mycobacteria and support the concept that FbpA-specific inhibitors, alone or in combination with other antibiotics, could provide an effective treatment to tuberculosis and other mycobacterial diseases. 相似文献
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Administration of B. diffusa leaf extract (BLEt; 200 mg/kg) for 4 weeks resulted in a significant reduction in thiobarbutric acid reactive substances and hydroperoxides, with a significant increase in reduced glutathione, superoxide dismutase, catalase, glutathione peroxidase and glutathione--S-transferase in liver and kidney of alloxan induced diabetic rats. The results suggest that BLEt has remarkable antidiabetic activity and can improve antioxidant status in alloxan induced diabetic rats. 相似文献