MET1 Is a Thylakoid-Associated TPR Protein Involved in Photosystem II Supercomplex Formation and Repair in Arabidopsis

Photosystem II (PSII) requires constant disassembly and reassembly to accommodate replacement of the D1 protein. Here, we characterize Arabidopsis thaliana MET1, a PSII assembly factor with PDZ and TPR domains. The maize (Zea mays) MET1 homolog is enriched in mesophyll chloroplasts compared with bundle sheath chloroplasts, and MET1 mRNA and protein levels increase during leaf development concomitant with the thylakoid machinery. MET1 is conserved in C3 and C4 plants and green algae but is not found in prokaryotes. Arabidopsis MET1 is a peripheral thylakoid protein enriched in stroma lamellae and is also present in grana. Split-ubiquitin assays and coimmunoprecipitations showed interaction of MET1 with stromal loops of PSII core components CP43 and CP47. From native gels, we inferred that MET1 associates with PSII subcomplexes formed during the PSII repair cycle. When grown under fluctuating light intensities, the Arabidopsis MET1 null mutant (met1) showed conditional reduced growth, near complete blockage in PSII supercomplex formation, and concomitant increase of unassembled CP43. Growth of met1 in high light resulted in loss of PSII supercomplexes and accelerated D1 degradation. We propose that MET1 functions as a CP43/CP47 chaperone on the stromal side of the membrane during PSII assembly and repair. This function is consistent with the observed differential MET1 accumulation across dimorphic maize chloroplasts.     

Omega-3 fatty acids concentrate production by enzyme-catalyzed ethanolysis of supercritical CO<Subscript>2</Subscript> extracted oyster oil

The separation of oil by a suitable technique from the Pacific oyster muscle is important for the utilization of the oil as a ω-3 polyunsaturated fatty acids (ω-3 PUFAs) source and production of bio-functional peptides/ oligosaccharides from oil-free residue. This study was conducted to prepare ω-3 PUFAs concentrate from supercritical carbon dioxide (SC-CO₂) extracted Pacific oyster oil by enzyme-catalyzed ethanolysis reactions. SC-CO₂ extractions were done at different temperatures and pressures to optimize suitable extraction conditions and extracted oils were compared with Soxhlet (n-hexane) extracted oil to evaluate the yield and quality. Oil extracted by SC-CO₂ at optimized conditions was used for ethanolysis reaction catalyzed by immobilized sn-1,3 specific lipases, namely Novozymes-435, Lipozyme TLIM, and Lipozyme RMIM to produce 2-monoacylglycerols (2-MAG) rich in ω-3 PUFAs. The optimum temperature and pressure for SC-CO₂ extractions of oyster oil was 50°C and 30 MPa. In this condition, the yield of oil was 5.96% and the acid, peroxide, free fatty acid, and p-anisidine values were 4.49 mg KOH/g, 4.72 meq/kg, 3.42%, and 10.03, respectively. The ω-3 PUFAs content significantly increased in 2-MAG obtained from Novozymes 435, Lipozyme TLIM, and Lipozyme RMIM to 43.03 ± 0.36, 45.95 ± 0.29, and 40.50 ± 0.77%, respectively (p < 0.05). A thin layer chromatography (TLC) analysis confirmed the production and separation of 2-MAG in the ethanolysis process. The ratio of total ω-3 to ω-6 fatty acids was almost twice in 2-MAG of SC-CO₂ extracted oyster oil. SC-CO₂ extracted Pacific oyster oil can be used for sn-1,3 specific lipases catalyzed ethanolysis to produce ω-3 PUFAs rich in 2-MAG.     

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.     

Microbiological treatment of industrial wastes containing toxic chromium involving successive use of bacteria,yeast and algae

Bacteria, yeasts, protozoa and algae, observed in industrial effluents from tanneries, were checked for their possible use in the detoxification of polluted water. Two bacterial strains were found to be highly resistant to Cr^VI. Several bacteria, yeasts and algae were observed to be capable of reducing Cr^VI to Cr^III.     

Experimental infection of rhesus monkeys with Entamoeba histolytica mimics human infection

Experimental infection of Entamoeba histolytica was successfully established in rhesus monkeys (Macaca mulatta). Parasites of proven pathogenicity maintained through liver passage in hamsters were used in this study. Laparotomized monkeys were inoculated intracecally/intrahepatically with trophozoites, or by oral administration of cysts (2000 cysts/ml). The cysts were isolated from an infected human stool sample. Formation of typical amebic lesions in the inoculated tissues along with alterations in hematologic indices were studied in the infected monkeys. All the experimentally inoculated monkeys showed leukocytosis and mild neutrophilia, while the hemoglobin content and levels of blood sugar and blood urea remained unaltered during the post-infection period. Specific antiamebic antibodies were readily detectable in post-infected sera.     

Watershed ‘chemical cocktails’: forming novel elemental combinations in Anthropocene fresh waters

In the Anthropocene, watershed chemical transport is increasingly dominated by novel combinations of elements, which are hydrologically linked together as ‘chemical cocktails.’ Chemical cocktails are novel because human activities greatly enhance elemental concentrations and their probability for biogeochemical interactions and shared transport along hydrologic flowpaths. A new chemical cocktail approach advances our ability to: trace contaminant mixtures in watersheds, develop chemical proxies with high-resolution sensor data, and manage multiple water quality problems. We explore the following questions: (1) Can we classify elemental transport in watersheds as chemical cocktails using a new approach? (2) What is the role of climate and land use in enhancing the formation and transport of chemical cocktails in watersheds? To address these questions, we first analyze trends in concentrations of carbon, nutrients, metals, and salts in fresh waters over 100 years. Next, we explore how climate and land use enhance the probability of formation of chemical cocktails of carbon, nutrients, metals, and salts. Ultimately, we classify transport of chemical cocktails based on solubility, mobility, reactivity, and dominant phases: (1) sieved chemical cocktails (e.g., particulate forms of nutrients, metals and organic matter); (2) filtered chemical cocktails (e.g., dissolved organic matter and associated metal complexes); (3) chromatographic chemical cocktails (e.g., ions eluted from soil exchange sites); and (4) reactive chemical cocktails (e.g., limiting nutrients and redox sensitive elements). Typically, contaminants are regulated and managed one element at a time, even though combinations of elements interact to influence many water quality problems such as toxicity to life, eutrophication, infrastructure corrosion, and water treatment. A chemical cocktail approach significantly expands evaluations of water quality signatures and impacts beyond single elements to mixtures. High-frequency sensor data (pH, specific conductance, turbidity, etc.) can serve as proxies for chemical cocktails and improve real-time analyses of water quality violations, identify regulatory needs, and track water quality recovery following storms and extreme climate events. Ultimately, a watershed chemical cocktail approach is necessary for effectively co-managing groups of contaminants and provides a more holistic approach for studying, monitoring, and managing water quality in the Anthropocene.     

Stereoselective Synthesis of (R)‐3‐Methylthalidomide by Piperidin‐2‐one Ring Assembly Approach

A simple and stereoselective synthesis of 3‐methylthalidomide, a configurationally stable thalidomide analog, is presented. Herein we describe the synthesis of (R)‐3‐methylthalidomide starting from (S)‐alanine by piperidin‐2‐one ring assembly approach in high yield and enantiomeric purity without using a chiral auxiliary or reagent. Starting from (R)‐alanine, the corresponding (S)‐3‐methylthalidomide can be prepared using the same methodology. Chirality 27:619–624, 2015. © 2015 Wiley Periodicals, Inc.     

Studies on sildenafil citrate (Viagra) interaction with DNA using electrochemical DNA biosensor

The interaction of sildenafil citrate (Viagra) with DNA was studied by using an electrochemical DNA biosensor. The binding mechanism of sildenafil citrate was elucidated by using constant current potentiometry and differential pulse voltammetry at DNA-modified glassy carbon electrode. The decrease in the guanine oxidation peak area or peak current was used as an indicator for the interaction in 0.2M acetate buffer (pH 5). The binding constant (K) values obtained were 2.01+/-0.05 x 10(5) and 1.97+/-0.01 x 10(5)M(-1) with constant current potentiometry and differential pulse voltammetry, respectively. A linear dependence of the guanine peak area or peak current was observed within the range of 1-40 microM sildenafil citrate with slope=-2.74 x 10(-4)s/microM, r=0.989 and slope=-2.78 x 10(-3)microA/microM, r=0.995 by using constant current potentiometry and differential pulse voltammetry, respectively. Additionally, binding constant values for sildenafil citrate-DNA interaction were determined for the pH range of 4-8 and in biological fluids (serum and urine) at pH 5. The influence of sodium and calcium ions was also studied to elucidate the mechanism of sildenafil citrate-DNA interaction under different solution conditions. The present study may prove to be helpful in extending our understanding of the anticancer activity of sildenafil citrate from cellular to DNA level.