Mutants of Salmonella typhimurium responding to cysteine or methionine: their nature and possible role in the regulation of cysteine biosynthesis.

Nineteen mutants of Salmonella typhimurium responding to either cysteine or methionine (cym) have been identified amongst cysteine (cys) and methionine (met) auxotrophs. Their growth responses to known intermediates in the related pathways of cysteine and methionine biosynthesis and complementation patterns in abortive transduction tests divided the mutants into six groups. Results of conjugation, cotransduction and deletion mapping experiments substantiated these groups, each of which carried a lesion within known cys genes. Enzyme assays on cym mutants from five of the six groups confirmed their cys gene deficiencies. Growth response and enzyme assay data were not consistent with mutants being leaky cys mutants (spared by methionine). None of eight cym mutants tested were able to convert [35S]methionine into [35S]cysteine. Selenate specifically inhibits the early enzymes of cysteine synthesis. In cym mutants this inhibition was relieved by cysteine but not by methionine, indicating that cym mutants require active cys enzymes for growth on methionine. There was evidence that methionine stimulated in vivo activity of cys enzymes in a cym mutant. Resistance to inhibition by 1,2,4-triazole results in reduced levels of the O-acetyl serine sulphydrylase. In cym mutants triazole resistance gave unstable suppression of the cym phenotype. Cym mutants may result from mutation in regulatory regions common to each of the cys genes, with the precise role of methionine as yet unknown.     

Exploring Coal Biodesulfurization Potential of a Novel Organic Sulfur Metabolizing Rhodococcus spp. (Eu-32) – A Case Study

Coal is one of the most abundant nonrenewable fossil fuels, in Pakistan. However, in general, the quality of coal is too low to offset the practical, economic, and regulatory barriers to its utilization. High sulfur content comes up as one of the bottlenecks in productive usage of indigenous coal. Biotechnology can emerge as a panacea for upgrading the huge reserves of high sulfur coal. In current study, the sulfur removal potential of Rhodococcus spp. (Eu-32) was investigated using coal from Dukki, Baluchistan, Pakistan. Biodesulfurization process was optimized for various parameters and maximum decrease of 40% and 60% in total and organic sulfur contents, respectively were achieved in 15 days. The Langmuir and Brunauer–Emmett–Teller (BET) surface areas of the biotreated coal were increased by 20 and 16 times, respectively. Scanning electron microscope showed higher tendency of attachment of bacterial cells to the coal particles. Our results revealed that Eu-32 could remove significant amounts of organic sulfur from coal and could be used in the pre-combustion operations with appropriate arrangements.     

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.     

SARS-CoV-2 nucleocapsid and Nsp3 binding: an in silico study

Archives of Microbiology - Severe acute respiratory syndrome virus 2 (SARS-CoV-2) belongs to the single-stranded positive-sense RNA family. The virus contains a large genome that encodes four...     

Growth and Physiology of Maize (Zea mays L.) in a Nickel-Contaminated Soil and Phytoremediation Efficiency Using EDTA

Journal of Plant Growth Regulation - Nickel (Ni) element is strongly phytotoxic at high concentrations for several plants, but due to its dual behavior and complicated chemistry, it has received...     

Observations on the floristic,life-form,leaf-size spectra and habitat diversity of vegetation in the Bhimber hills of Kashmir Himalayas

Vegetation analysis provides the prerequisites to understand the overall community structure and function of any ecosystem and is a fundamental requirement for the precise evaluation of biodiversity. Although many studies have assessed floristic attributes of specific areas, there are still unexplored regions, as is the case of the mountain region in the Kashmir Himalayas. Current research highlighted the recent findings of the scientific characterization of floristic and ecological aspects on the forest flora found in the Bhimber hills, Pakistan. Floristically, a total of 93 species belonging to 80 genera in 41 families were recorded. The species distribution patterns across the families were disproportionate with half of the species contributed by 8 families and 25 families were monotypic. Based on the floristic analysis, Asteraceae was the largest family with 12% of species followed by Poaceae with (11%) species. PAST software, a multivariate ecological community analysis was used to classify the species similarities and differences among the different habitat types. According to the habitat wise distribution, 21% of species were growing in the natural forest habitat, while 15% of species were dispersed in highly distributed habitats along roadsides and 8% on pedestrians. In terms of functional diversity, the herbaceous growth form was dominant (58%). The biological spectrum revealed therophytes as the dominant life form as it indicates the disturbed habitat vegetation. The phytogeographical analysis revealed that the maximum (69%) species were native, while the minimum (31%) species were exotic. Thus, the study of these functional and habitat diversity patterns can significantly improve our understanding of the ecological aspects of the flora in the geographical location. This information may additionally be useful in devising management plans to ensure sustainable utilization and better management of forest landscapes in this Himalayan region.     

PGC-1 Coactivators Regulate MITF and the Tanning Response

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Highlights? PGC-1 induces pigment formation in melanocytes ? PGC-1s activate expression of MITF ? α-MSH induces PGC-1s, which are required for induction of melanogenic genes ? eQTLs in human PGC-1β are associated with tanning ability and melanoma protection     

Interbirth interval and litter size of free-ranging Bengal tiger (Panthera tigris tigris) in dry tropical deciduous forests of India

We studied the interbirth interval (IBI) and litter size of the population of free-ranging Bengal tigers (Panthera tigris tigris) in dry tropical deciduous forests in Ranthambhore Tiger Reserve (RTR), Rajasthan, and Pench Tiger Reserve (PTR), Madhya Pradesh, between April 2005 and June 2011. Data on 15 breeding females in RTR and nine breeding females in PTR were collected using camera trapping, direct observation and radio-telemetry. The mean?±?standard error of IBI (months) in RTR was 33.4?±?3.7 and in PTR was 25.2?±?1.8. A significant difference was observed between the mean IBI of tigresses in RTR and those in PTR (df?=?9, P?=?0.04). The estimated mean litter size in RTR was 2.3?±?0.1 and that in PTR was 2.9?±?0.2. There was a significant difference between the litter size in RTR and that in PTR (χ ²?=?12.04, P?=?0.017, df?=?4). Since RTR and PTR are the important source populations of tigers in the Western and Central Indian landscapes, we propose that the tigers in these reserves be monitored, particularly for reproductive traits that are essential for understanding aspects of their population ecology.     

Studies on the regioselectivity and kinetics of the action of trypsin on proinsulin and its derivatives using mass spectrometry

Human M-proinsulin was cleaved by trypsin at the R³¹R³²–E³³ and K⁶⁴R⁶⁵–G⁶⁶ bonds (B/C and C/A junctions), showing the same cleavage specificity as exhibited by prohormone convertases 1 and 2 respectively. Buffalo/bovine M-proinsulin was also cleaved by trypsin at the K⁵⁹R⁶⁰–G⁶¹ bond but at the B/C junction cleavage occurred at the R³¹R³²–E³³ as well as the R³¹–R³²E³³ bond. Thus, the human isoform in the native state, with a 31 residue connecting C-peptide, seems to have a unique structure around the B/C and C/A junctions and cleavage at these sites is predominantly governed by the structure of the proinsulin itself. In the case of both the proinsulin species the cleavage at the B/C junction was preferred (65%) over that at the C/A junction (35%) supporting the earlier suggestion of the presence of some form of secondary structure at the C/A junction. Proinsulin and its derivatives, as natural substrates for trypsin, were used and mass spectrometric analysis showed that the k_cat./K_m values for the cleavage were most favourable for the scission of the bonds at the two junctions (1.02 ± 0.08 × 10⁵ s^− 1 M^− 1) and the cleavage of the K²⁹–T³⁰ bond of M-insulin-RR (1.3 ± 0.07 × 10⁵ s^− 1 M^− 1). However, the K²⁹–T³⁰ bond in M-insulin, insulin as well as M-proinsulin was shielded from attack by trypsin (k_cat./K_m values around 1000 s^− 1 M^− 1). Hence, as the biosynthetic path follows the sequence; proinsulin → insulin-RR → insulin, the K²⁹–T³⁰ bond becomes shielded, exposed then shielded again respectively.