Plasmid-mediated drug resistance of shigellae in Kuwait

Of 153 clinical isolates of shigellae examined, 64.7% belonged toShigella flexneri, 18.9% toSh. sonnei, 11.8% toSh. boydii and 4.6% toSh. dysenteriae. Part of these isolates were resistant to sulfamethoxazole and streptomycin (88.2% each), ampicillin (66.70, tetracycline (63.40 and co-trimoxazole (43.10, with levels of resistance (MIC₅₀ and MIC₉₀) being invariably high. Resistance to three or more drugs (multidrug resistance) was seen in 77.8% of the isolates. All the 25 strains examined for transfer of resistance contained R-plasmids, both autotransferable and non-autotransferable (mobilized by transfer factor X). The frequency of transfer of different r-determinants varied from 2.7 · 10^–8 to 1.4 · 10.     

Comparison of superovulatory response of mature outbred mice treated with FSH or PMSG and developmental potential of embryos produced

A superovulatory treatment for mice based on FSH administration was compared with a standard one based on PMSG. Our aim was to determine if a mean number of embryos recovered per donor could be increased and if in vitro or in vivo viability was affected by the hormonal treatment used. Thus, female Swiss mice were subjected to 2 superovulatory treatments, and the 1-cell and 2-cell stage embryos were cultured in 2 different media to the blastocyst stage or were transferred to pseudopregnant recipients. The data show that despite a lower mating percentage (52% with FSH vs 66% with PMSG), the FSH-treated mice provided twice the number of total embryos (53.4 vs 24.5) with a similar percentage of morphologically normal embryos (74% for FSH vs 69% for PMSG). We also found that in vitro culture results can be influenced by the source of gonadotropins depending on the culture medium used. A culture medium such as CZB which prevents the 2-cell block, provided the same developmental rates regardless of hormonal treatment used. However, with M-16 medium, which does not prevent this blockage, only 39% of the 2-cell FSH-derived embryos and 49% of the PMSG-derived 2-cell embryos developed into blastocysts (P<0.05). FSH-derived embryos resulted in a higher percentage of pregnant recipients (73 vs 56%) than PMSG-derived embryos, but the number of alive fetuses and the number of implantations per pregnant recipient was affected only by the kind of culture system used before transfer. The results show that FSH can provide very good superovulatory response in mice, thus reducing the number of donors needed for a given experiment and providing embryos of at least the same quality as those derived from the standard PMSG treatment.     

Cross-Reactions of Human Lupus Autoantibodies with 8-Methoxypsoralen Photomodified DNA Fragments

DNA fragments of around 200 base pair (average size) have been covalently crosslinked with 8-methoxypsoralen under 365 nm UV light. The photoadduct, induced antibodies in rabbits with a titer of > 1:12,800 by direct bindng ELISA. Binding data showed that the induced antibodies are conformation-specific recognizing restricted conformational change at site of crosslinking. Human autoantibodies against DNA, bound not only to native DNA but to the photomodified DNA fragment as well. In addition, binding patterns of SLE sera obtained from different patients were remarkably similar, indicating the recognition of altered conformation of the modified polymer by naturally occurring SLE anti-DNA autoantibodies.     

Plant growth-promoting Bacillus sp. strain SDA-4 confers Cd tolerance by physio-biochemical improvements,better nutrient acquisition and diminished Cd uptake in Spinacia oleracea L.

Cadmium (Cd) is highly toxic metal for plant metabolic processes even in low concentration due to its longer half-life and non-biodegradable nature. The current study was designed to assess the bioremediation potential of a Cd-tolerant phytobeneficial bacterial strain Bacillus sp. SDA-4, isolated, characterized and identified from Chakera wastewater reservoir, Faisalabad, Pakistan, together with spinach (as a test plant) under different Cd regimes. Spinach plants were grown with and without Bacillus sp. SDA-4 inoculation in pots filled with 0, 5 or 10 mg kg⁻¹ CdCl₂-spiked soil. Without Bacillus sp. SDA-4 inoculation, spinach plants exhibited reduction in biomass accumulation, antioxidative enzymes and nutrient retention. However, plants inoculated with Bacillus sp. SDA-4 revealed significantly augmented growth, biomass accumulation and efficiency of antioxidative machinery with concomitant reduction in proline and MDA contents under Cd stress. Furthermore, application of Bacillus sp. SDA-4 assisted the Cd-stressed plants to sustain optimal levels of essential nutrients (N, P, K, Ca and Mg). It was inferred that the characterized Cd-tolerant PGPR strain, Bacillus sp. SDA-4 has a potential to reduce Cd uptake and lipid peroxidation which in turn maintained the optimum balance of nutrients and augmented the growth of Cd-stressed spinach. Analysis of bioconcentration factor (BCF) and translocation factor (TF) revealed that Bacillus sp. SDA-4 inoculation with spinach sequestered Cd in rhizospheric zone. Research outcomes are important for understanding morpho-physio-biochemical attributes of spinach-Bacillus sp. SDA-4 synergy which might provide efficient strategies to decrease Cd retention in edible plants and/or bioremediation of Cd polluted soil colloids.     

Changes in Phyto-Chemical Status upon Viral Infections in Plant: A Critical Review

Most damaging plant diseases have been caused by viruses in the entire world. In tropical and subtropical areas, the damage caused by plant virus leads to great economic and agricultural losses. Single stranded DNA viruses (geminiviruses) are the most perilous pathogens which are responsible for major diseases in agronomic and horticultural crops. Significantly begomoviruses and mastreviruses are the biggest genus of plant infecting viruses, transmitted though Bemisia tabaci and members of Cicadellidae respectively. Plants possesses some naturally existing chemicals term as phyto-chemicals which perform important functions in the plant. Some antioxidant enzymes are used by plants for self-defense upon foreign invasion of infection. This review explains the present perceptive of influence of viral infections on phyto-chemicals, oxidative enzymes and biochemical changes occurring in the plant. Viral infection mediated phyto-chemical changes in plants mainly includes: up and down regulation of photosynthetic pigment, increase in the concentration of phenolic compounds, elevation of starch content in the leaf and up & down regulation of anti-oxidative enzymes including (GPX) guaiacol peroxidase, (PPO) polyphenol oxidase, (APX) ascorbate peroxidase, (SOD) superoxide dismutase and (CTA) catalase. These changes lead to initiation of hypersensitive response, by thicken of the leaf lamina, lignification under the leaf surface, blocking to stomatal openings, systematic cell death, generation of reactive oxidative species (ROS), activation of pathogen mediated resistance pathways i.e., production of salicylic acid and jasmonic acid. Collectively all the physiological changes in the plant due to viral infection supports the activation of defense mechanism of the plant to combat against viral infection by limiting virus in specific area, followed with the production of barriers for pathogen, accumulation of starch in the leaf and excess production of (ROS). These strategies used by the plant to prevent the spread of virus in whole plant and to minimize the risk of severe yield loss.     

A study on risk assessment of effect of hematoxylin dye on cytotoxicity and nephrotoxicity in freshwater fish: Food and water security prospective research

The cytotoxicity in freshwater fishes due to different industrial dyes in industrial effluents is a major worldwide issue. Hematoxylin dye has a wide range of uses in textile industries and laboratories. This study was aimed to evaluate the toxic effects of hematoxylin's sublethal effect in vitro in Cirrhinus mrigala. The fish was exposed to different grading concentrations of dye in the aquarium. Fish were sacrificed and dissected to remove the kidney after exposure to hematoxylin dye for specific time intervals. Nephrotoxicity and cytotoxicity induced by this dye were detected through histopathology by using the paraffin wax method. Immediate mortality of fish was noticed against the exposure to 0.08 g/L (LC₅₀) concentration of dye, but at 0.008 mg/L and 0.018 mg/L, it showed tremendous tissue damage in the kidneys, significant reduction in fish growth. This dye induced many alterations in the kidney such as tubular degeneration, vacuolation, shrinkage of a glomerulus, reduced lumen, congestion in the kidney, glomerulonephritis, absence of Bowmen space, necrosis of the hematopoietic interstitial tissues, clogging of tubules, necrosis in the glomerulus and increased space between glomerulus and bowmen's capsule. Although this dye has a wide range of biological and industrial applications, a minute amount of hematoxylin released in effluents is quite toxic to aquatic fauna.     

Green synthesis of ZnO nanoparticles for antimicrobial and vegetative growth applications: A novel approach for advancing efficient high quality health care to human wellbeing

The present work aims to synthesize zinc oxide (ZnO) nanoparticles via green approaches using leaf extract of Parthenium hysterophorus. UV–vis and FT-IR tests confirmed the existence of biomolecules, active materials, and metal oxides. The X-ray diffraction structural study exposes the ZnO nanoparticles formation with hexagonal phase structures. SEM and TEM analysis reveal surface morphologies of ZnO nanoparticles and most of them are spherical with a size range of 10 nm. ZnO nanoparticles were revealed strong antimicrobial activity against both bacterial and fungal strains. The germination of seeds and vegetative growth of Sesamum indicum has been greatly improved.