UDP-N-acetylglucosamine enolpyruvyl transferase from <Emphasis Type="Italic">Pseudomonas aeruginosa</Emphasis>

Multi-drug resistant Pseudomonas aeruginosa (MDRPA) are emerging as a major threat in the hospitals as they have become resistant to current antibiotics. There is an immediate requirement of drugs with novel mechanisms as the pipeline of investigational drugs against these organisms is lean. UDP-N-acetylglucosamine enolpyruvyl transferase (MurA) enzyme that catalyzes the first committed step of bacterial cell wall biosynthesis is an ideal target for the discovery of novel antibiotics against Gram negative pathogens as they have only one copy of murA gene in its genome. We have performed biochemical characterization and comparative kinetic analysis of MurA from E. coli and P. aeruginosa. Both enzymes were active at broad range of pH with temperature optima of 37°C. Metal ions did not enhance the activity of both enzymes. These enzymes had an apparent affinity constant (K _m ) for its substrate UDP-N-acetylglucosamine 36 ± 5.2 and 17.8 ± 2.5 μM and for phosphoenolpyruvate 0.84 ± 0.13 μM and 0.45 ± 0.07 μM for E. coli and P. aeruginosa enzymes respectively. Both the enzymes showed 5–7 fold shift in IC₅₀ for the known inhibitor fosfomycin upon pre-incubation with the substrate UDP-N-acetylglucosamine. This observation was used to develop a novel rapid sensitive high throughput assay for the screening of MurA inhibitors.     

Synthesis and cancer cell cytotoxicity of substituted xanthenes

A series of substituted xanthenes was synthesized and screened for activity using DU-145, MCF-7, and HeLa cancer cell growth inhibition assays. The most potent compound, 9g ([N,N-diethyl]-9-hydroxy-9-(3-methoxyphenyl)-9H-xanthene-3-carboxamide), was found to inhibit cancer cell growth with IC₅₀ values ranging from 36 to 50 μM across all three cancer cell lines. Structure–activity relationship (SAR) data is presented that indicates additional gains in potency may be realized through further derivatization of the compounds (e.g., the incorporation of a 7-fluoro substituent to 9g). Results are also presented that suggest the compounds function through a unique mechanism of action as compared to that of related acridine and xanthone anticancer agents (which have been shown to intercalate into DNA and inhibit topoisomerase II activity). A structural comparison of these compounds suggests the differences in function may be due to the structure of the xanthene heterocycle which adopts a nonplanar conformation about the pyran ring.     

Fruit-specific Over-expression of LeEXP1 Gene in Tomato Alters Fruit Texture

Expansins are cellular proteins with diverse physiological functions. Expression of fruit-specific expansin gene in tomato is associated with fruit softening — a desirable trait from the processing point of view. In the present study, an expansin gene LeEXP1 was introduced via Agrobacterium tumefaciens in sense orientation under the control of a fruit-specific promoter LeACS4 with nptII gene as selection marker in Indian tomato cv Pusa Uphar. PCR detection and Southern blot analysis confirmed the integration of the transgene in the transformed tomato plants. RT-PCR and northern blot analysis using total RNA isolated from leaves and fruits confirmed over-expression of the LeEXP1 gene in transgenic fruits as compared to the wild type plants. Apart from the visual change in increased red colouration of fruits at different stages of ripening, overexpression of the LeEXP1 gene resulted in enhanced fruit softening, as determined by force required to rupture the fruit pericarp, in the transgenic fruits from breaker stage onwards as compared to the non-transformed wild type fruits. The results thus suggest an improvement in texture of the LeEXP1 over-expressing fruits, which might be useful for tomato processing industry.     

Plasmodesmata the Nano Bridges in Plant Cell: Are the Answer for All the Developmental Processes?

Russian Journal of Plant Physiology - Plants establish tiny, cellular signaling pathways playing a unique coordination role in growth and development. Plasmodesmata are playing a central role in...     

Synthesis,Cytotoxicity and Antimicrobial Evaluation of New Coumarin‐Tagged β‐Lactam Triazole Hybrid

A series of coumarin‐tagged β‐lactam triazole hybrids ( 10a – 10o ) were synthesized and tested for their cytotoxic activity against MDA‐MB‐231 (triple negative breast cancer), MCF‐7 (estrogen receptor positive breast cancer (ER+)) and A549 (human lung carcinoma) cancer cell lines including one normal cell line, HEK‐293 (human embryonic kidney). Two compounds 10b and 10d exhibited substantial cytotoxic effect against MCF‐7 cancer cell lines with IC₅₀ values of 53.55 and 58.62 μm , respectively. More importantly, compounds 10b and 10d were non‐cytotoxic against HEK‐293 cell lines. Structure–activity relationship (SAR) studies suggested that the nitro and chloro group at the C‐3 position of phenyl ring are favorable for anticancer activity, particularly against MCF‐7 cell lines. Furthermore, antimicrobial evaluation of these compounds revealed modest inhibition of examined pathogenic strains with compounds 10c and 10i being the most promising antimicrobial agents against Pseudomonas aeruginosa and Candida albicans, respectively.     

The impact of reducing fatty acid desaturation on the composition and thermal stability of rapeseed oil

Oilseed rape (Brassica napus) is the third largest source of vegetable oil globally. In addition to food uses, there are industrial applications that exploit the ability of the species to accumulate the very‐long‐chain fatty acid (VLCFA) erucic acid in its seed oil, controlled by orthologues of FATTY ACID ELONGASE 1 (Bna.FAE1.A8 and Bna.FAE1.C3). The proportion of polyunsaturated fatty acids (PUFAs) in rapeseed oil is predicted to affect its thermal stability and is controlled by orthologues of FATTY ACID DESATURASE 2, particularly Bna.FAD2.C5. Our aim was to develop rapeseed lines combining high erucic and low PUFA characters and to assess the impact on thermal stability of the oil they produce. The new type of rapeseed oil (high erucic low polyunsaturate; HELP) contained a substantially greater proportion of erucic acid (54%) compared with high erucic rapeseed oil (46%). Although the total VLCFA content was greater in oil from HELP lines (64%) than from high erucic rapeseed (57%), analysis of triacylglycerol composition showed negligible incorporation of VLCFAs into the sn‐2 position. Rancimat analysis showed that the thermal stability of rapeseed oil was improved greatly as a consequence of reduction of PUFA content, from 3.8 and 4.2 h in conventional low erucic and high erucic rapeseed oils, respectively, to 11.3 and 16.4 h in high oleic low PUFA (HOLP) and HELP oils, respectively. Our results demonstrate that engineering of the lipid biosynthetic pathway of rapeseed, using traditional approaches, enables the production of renewable industrial oils with novel composition and properties.     

Association of interleukin-18 genotypes (−607C > A) and (−137 G > C) with the hepatitis B virus disease progression to hepatocellular carcinoma

Chronic infection with HBV has been reported to be associated with the development of HCC. The inflammation mounted by cytokine-mediated immune system plays an important role in the pathogenesis of HBV-associated HCC. IL-18 is a pro-inflammatory cytokine whose role in the development of HBV-associated chronic to malignant disease state has not been much studied. The present study was conceived to determine the role of genetic polymorphisms in IL-18, serum levels of IL-18, and expression level of its signal transducers in the HBV disease progression. A total of 403 subjects were enrolled for this study including 102 healthy subjects and 301 patients with HBV infection in different diseased categories. Polymorphism was determined using PCR–RFLP. Genotypic distributions between the groups were compared using odd’s ratio and 95% CI were calculated to express the relative risk. Circulating IL-18 levels were determined by ELISA. Expression levels of pSTAT-1 and pNF?B was determined by western blotting. In case of IL-18(??607C?>?A), the heterozygous genotype (CA) was found to be a protective factor while in case of IL-18(??137G?>?C) the heterozygous genotype (GC) acted as a risk factor for disease progression from HBV to HCC. Moreover, serum IL-18 levels were significantly increased during HBV disease progression to HCC as compared to controls. Also the levels of activated signal transducers (pSTAT-1 and pNF-κB) of IL-18 in stimulated PBMCs were significantly increased during HBV to HCC disease progression. These findings suggest that IL-18 has the potential to act as a biomarker of HBV-related disease progression to HCC.