Physiological and biochemical mechanisms of silicon-induced copper stress tolerance in cotton (<Emphasis Type="Italic">Gossypium hirsutum</Emphasis> L.)

Accumulation of excess copper (Cu) in agricultural soils can decrease growth and quality of crops grown on these soils and a little information is available on the role of silicon (Si) in reducing Cu toxicity in plants. A hydroponic study was conducted to investigate the effects of Si (1.0 mM) on growth and physiology of cotton seedlings grown on different Cu (0, 25, and 50 µM) concentrations. Elevated levels of Cu decreased growth, biomass, photosynthetic pigments, and gas exchange characteristics, and increased the electrolyte leakage (EL), hydrogen peroxide (H₂O₂), and thiobarbituric acid reactive substances (TBARS) contents in leaf, stem, and roots of cotton seedlings. Cu stress alone decreased the activities of key antioxidant enzymes in cotton seedlings. Exogenous application of Si alleviated the toxic effects of Cu on cotton seedlings by improving growth, photosynthetic pigments, and gas exchange characteristics under Cu stress. The Si application decreased Cu concentrations in leaves, stem, and roots as compared with the control plants. Furthermore, Si decreased oxidative stress as evidenced by decreased EL, H₂O₂, and TBARS contents, and increased the antioxidant enzyme activities in cotton seedlings. This study provides evidences of Si-mediated reduction of Cu toxicity in cotton seedlings at physiological and biochemical levels.     

Pattern of Drug Resistance and Risk Factors Associated with Development of Drug Resistant Mycobacterium tuberculosis in Pakistan

Background

Drug resistant tuberculosis (DR-TB) is a major public health problem in developing countries such as Pakistan.

Objective

The current study was conducted to assess the frequency of drug resistant tuberculosis including multi drug resistance (MDR- TB) as well as risk factors for development of DR-TB, in Punjab, Pakistan.

Methodology

Drug susceptibility testing (DST) was performed, using proportion method, for 2367 culture positive Mycobacterium tuberculosis (MTB) cases that were enrolled from January 2012 to December 2013 in the province of Punjab, Pakistan, against first-line anti-tuberculosis drugs. The data was analyzed using statistical software; SPSS version 18.

Results

Out of 2367 isolates, 273 (11.5%) were resistant to at least one anti-TB drug, while 221 (9.3%) showed MDR- TB. Risk factors for development of MDR-TB were early age (ranges between 10–25 years) and previously treated TB patients.

Conclusion

DR-TB is a considerable problem in Pakistan. Major risk factors are previous history of TB treatment and younger age group. It emphasizes the need for effective TB control Program in the country.     

Stability analysis of pine wilt disease model by periodic use of insecticides

This work is related to qualitative behaviour of an epidemic model of pine wilt disease. More precisely, we proved that the reproductive number has sharp threshold properties. It has been shown that how vector population can be reduced by the periodic use of insecticides. Numerical simulations show that epidemic level of infected vectors becomes independent of saturation level by including the transmission through mating.     

Pattern of sex steroids secretion and their relationship with embryo yield in Jersey cows superovulated with PMSG

The levels of progesterone and estrogen secretion were studied in relationship to the superovulatory response in Jersey cows. Progesterone and estrogen concentrations were measured in superovulated Jersey cows with the objective of correlating the patterns of steroid secretion with embryo yield and quality. Pregnant mare serum gonadotropin (PMSG) was used in combination with prostaglandin F(2) alpha analogue to induce superovulation in 18 multiparous, cyclic cows. Serum progesterone and estradiol levels from cows which exhibited estrus within 24 to 48 h after prostaglandin administration (n=13) were used to estimate the superovulatory response. Sex steroid concentrations at the day of estrus (Day 0) was a strong indicator of embryo yield. Progesterone was negatively (r=-0.56) and estrogen positively (r=0.80) correlated to the number of embryos collected. Dramatic increase in progesterone from Day 0 to Day 7 was a significant indicator of embryo yield. A higher rise of estrogen in the follicular phase was an indicator of a larger number of growing follicles and, consequently, better superovulatory response. Nonresponding animals did not show any significant change in the hormonal profile from the day of PMSG treatment to the day of embryo collection. The estimation of progesterone and estradiol concentrations, simultaneously, gave a more objective prediction of embryo yield.     

Production, rapid purification and catalytic characterization of extracellular phytase from Aspergillus ficuum

A rapid purification scheme utilizing three chromatographic steps resulted in 6 fold purification of Aspergillus ficuum phytase (myo-inositol-hexakisphosphate 3-phosphohydrolase, EC 3.1.3.8). At pH 5.0 and 60 degrees C the enzyme performed acceptably for 2.0 hr with only 30% diminished catalytic rate at the end. Substrate concentration exceeding 2mM was inhibitory. The inorganic orthophosphate, the product and a weak inhibitor, exhibited a Ki of 1.9 x 10(-3)M. The extracellular phytase has the potential for industrial use since it can be over produced, easily purified, remain catalytically active for a longer period and is not subjected to severe product inhibition.     

Role of Burkholderia cepacia CS8 in Cd-stress alleviation and phytoremediation by Catharanthus roseus

The current study was performed to assess the effect of Burkholderia cepacia CS8 on the phytoremediation of cadmium (Cd) by Catharanthus roseus grown in Cd-contaminated soil. The plants cultivated in Cd amended soil showed reduced growth, dry mass, gas-exchange capacity, and chlorophyll contents. Furthermore, the plants exhibited elevated levels of malondialdehyde (MDA) and hydrogen peroxide (H₂O₂) under Cd stress. The bacterized plants showed higher shoot length, root length; fresh and dry weight. The improved stress tolerance in inoculated plants was attributed to the reduced quantity of MDA and H₂O₂, enhanced synthesis of protein, proline, phenols, flavonoids, and improved activity of antioxidant enzymes including peroxidase, superoxide dismutase, ascorbate peroxidase, and catalase. Similarly, the 1-aminocyclopropane-1-carboxylate deaminase activity, phosphate solubilization, auxin, and siderophore production capability of B. cepacia CS8 improved growth and stress alleviation in treated plants. The bacterial inoculation enhanced the amount of water extractable Cd from soil. Furthermore, the inoculated plants showed higher bioconcentration factor and translocation factor. The current study exhibits that B. cepacia CS8 improves stress alleviation and phytoextraction potential of C. roseus plants growing under Cd stress.     

Joint mode selection and user association in D2D enabled multitier C-RAN

Cluster Computing - The device-to-device D-2-D Communication empowered Cloud Radio Access Network (CRAN) which is examined to be auspicious system model, gives energy efficiency and high data rate....     

Advances and challenges in cancer treatment and nutraceutical prevention: the possible role of dietary phenols in BRCA regulation

Phytochemistry Reviews - Over the years, the attention towards the role of phytochemicals in dietary natural products in reducing the risk of developing cancer is rising. Cancer is the second...     

Isolation and enzyme-inhibition studies of the chemical constituents from Ajuga bracteosa

Bractin A (=(2S,3S,4R,5E)-2-{[(2R)-2-hydroxydodecanoyl]amino}triacont-5-ene-1,3,4-triol; 1) and bractin B (=(2S,3S,4R,5E,8E)-2-{[(2R)-2-hydroxyhexacosanoyl]amino}pentadeca-5,8-diene-3,4,15-triol 1-O-beta-D-glucopyranoside; 2), new sphingolipids, and bractic acid (=(5Z,10Z,15Z)-2-decyl-4,7,8,12,13,17,18-heptahydroxy-20,23-dioxopentacosa-5,10,15-trienoic acid; 3), a long-chain polyhydroxy acid, were isolated from the whole plant Ajuga bracteosa along with four known diterpenoids 4-7. Their structures were deduced by spectral studies including 1D- and 2D-NMR spectroscopy. Compounds 1-3 displayed inhibitory potential against enzyme lipoxygenase, while compounds 4-7 inhibited cholinesterase enzymes in a concentration-dependent manner with IC(50) values in the range 10.0-33.0, 14.0-35.2, and 10.0-19.0 microM for lipoxygenase, acetylcholinesterase, and butyrylcholinesterase, respectively. Lineweaver-Burk, and Dixon plots, and their secondary replots indicated that all compounds exhibit non-competitive type of inhibition with K(i) values in the range of 9.5-35.2, 15.2-36.0, and 11.6-20.5 microM, for lipoxygenase, acetylcholinesterase, and butyrylcholinesterase, respectively.