Simultaneous inhibition of anti‐coagulation and inflammation: crystal structure of phospholipase A2 complexed with indomethacin at 1.4 Å resolution reveals the presence of the new common ligand‐binding site

A novel ligand‐binding site with functional implications has been identified in phospholipase A₂ (PLA₂). The binding of non‐steroidal anti‐inflammatory agent indomethacin at this site blocks both catalytic and anti‐coagulant actions of PLA₂. A group IIA PLA₂ has been isolated from Daboia russelli pulchella (Russell's viper) which is enzymatically active as well as induces a strong anti‐coagulant action. The binding studies have shown that indomethacin reduces the effects of both anti‐coagulant and pro‐inflammatory actions of PLA₂. A group IIA PLA₂ was co‐crystallized with indomethacin and the structure of the complex has been determined at 1.4 Å resolution. The structure determination has revealed the presence of an indomethacin molecule in the structure of PLA₂ at a site which is distinct from the conventional substrate‐binding site. One of the carboxylic group oxygen atoms of indomethacin interacts with Asp 49 and His 48 through the catalytically important water molecule OW 18 while the second carboxylic oxygen atom forms an ionic interaction with the side chain of Lys 69. It is well known that the residues, His 48 and Asp 49 are essential for catalysis while Lys 69 is a part of the anti‐coagulant loop (residues, 54–77). Indomethacin binds in such a manner that it blocks the access to both, it works as a dual inhibitor for catalytic and anti‐coagulant actions of PLA₂. This new binding site in PLA₂ has been observed for the first time and indomethacin is the first compound that has been shown to bind at this novel site resulting in the prevention of anti‐coagulation and inflammation. Copyright © 2009 John Wiley & Sons, Ltd.     

Innate immune response and disease resistance in Carassius auratus by triherbal solvent extracts

This study reports the effect of aqueous, ethanol and methanol triherbal solvent extract from Azadirachta indica, Ocimum sanctum and Curcuma longa on innate immune mechanisms such as phagocytosis activity, respiratory burst activity, alternative complement activity and lysozyme activity and disease resistance in goldfish (Carassius auratus) against Aeromonas hydrophila. Fish were intraperitoneally injected with different doses of 0, 5, 50 and 100 mg kg⁻¹ body weight of each triherbal solvent extracts. The functional immunity in terms of percentage mortality and Relative Percent Survival (RPS) and innate immune response was assessed on week 1, 2 and 4 by challenging with live A. hydrophila (1 × 10⁷ cells ml⁻¹). All the chosen innate immune parameters were enhanced in the ethanol and methanol triherbal solvent extract treatment after week 2. However, the aqueous triherbal extract was enhanced only after week 4. The ethanol and methanol triherbal solvent extracts administration preceding the challenge with live A. hydrophila decreased the percentage mortality in the experimental groups with the consequence increase in RPS values. The study indicates that all the doses of ethanol or methanol triberbal solvent extracts could be positively influence the immune response and protect the heath status of goldfish against A. hydrophila infection.     

Understanding the molecular basis of plant growth promotional effect of Pseudomonas fluorescens on rice through protein profiling

Background  

Plant Growth Promoting Rhizobacteria (PGPR), Pseudomonas fluorescens strain KH-1 was found to exhibit plant growth promotional activity in rice under both in-vitro and in-vivo conditions. But the mechanism underlying such promotional activity of P. fluorescens is not yet understood clearly. In this study, efforts were made to elucidate the molecular responses of rice plants to P. fluorescens treatment through protein profiling. Two-dimensional polyacrylamide gel electrophoresis strategy was adopted to identify the PGPR responsive proteins and the differentially expressed proteins were analyzed by mass spectrometry.     

Supplementation of vitamin E and selenium prevents hyperoxaluria in experimental urolithic rats

Renal injury is considered as one of the prerequisites for calcium oxalate retention. In order to determine the role of lipid peroxidation related effects for hyperoxaluria, we evaluated the alterations in lipid peroxidation, antioxidants and oxalate synthesizing enzymes in lithogenic rats with response to vitamin E + selenium treatment. In kidney of lithogenic rats, the level of lipid peroxidation and the activities of oxalate synthesizing enzymes were found to be increased whereas the levels/activities of non-enzymatic and enzymatic antioxidants were found to be decreased. The urinary excretion of both oxalate and calcium were significantly elevated. Supplementation of lithogenic rats with vitamin E + selenium decreased the levels of lipid peroxides and the activities of oxalate synthesizing enzymes like glycolic acid oxidase (GAO), lactate dehydrogenase (LDH), xanthine oxidase (XO) with a concomitant increase in the activities of enzymatic antioxidants like superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and glucose-6-phosphate dehydrogenase (G6PDH) and increased levels of non-enzymatic antioxidants like ascorbic acid, alpha-tocopherol and reduced glutathione (GSH). The urinary excretion of oxalate and calcium were normalized. The antioxidants vitamin E + selenium thereby protected from hyperoxaluria.     

Metabolic Reprogramming during Purine Stress in the Protozoan Pathogen Leishmania donovani

The ability of Leishmania to survive in their insect or mammalian host is dependent upon an ability to sense and adapt to changes in the microenvironment. However, little is known about the molecular mechanisms underlying the parasite response to environmental changes, such as nutrient availability. To elucidate nutrient stress response pathways in Leishmania donovani, we have used purine starvation as the paradigm. The salvage of purines from the host milieu is obligatory for parasite replication; nevertheless, purine-starved parasites can persist in culture without supplementary purine for over three months, indicating that the response to purine starvation is robust and engenders parasite survival under conditions of extreme scarcity. To understand metabolic reprogramming during purine starvation we have employed global approaches. Whole proteome comparisons between purine-starved and purine-replete parasites over a 6–48 h span have revealed a temporal and coordinated response to purine starvation. Purine transporters and enzymes involved in acquisition at the cell surface are upregulated within a few hours of purine removal from the media, while other key purine salvage components are upregulated later in the time-course and more modestly. After 48 h, the proteome of purine-starved parasites is extensively remodeled and adaptations to purine stress appear tailored to deal with both purine deprivation and general stress. To probe the molecular mechanisms affecting proteome remodeling in response to purine starvation, comparative RNA-seq analyses, qRT-PCR, and luciferase reporter assays were performed on purine-starved versus purine-replete parasites. While the regulation of a minority of proteins tracked with changes at the mRNA level, for many regulated proteins it appears that proteome remodeling during purine stress occurs primarily via translational and/or post-translational mechanisms.     

Management of Erectile Dysfunction in the Hypogonadal Man: A Case-Based Review

Erectile dysfunction (ED) has emerged as an important marker of cardiovascular and overall health, independent of other known conventional risk factors. ED often precedes coronary artery disease in half of affected subjects, and could indicate the presence of cardiovascular pathology. The pathophysiology and role of androgens in sexual function are described, along with the relevant literature on the effects of aging in erectile and gonadal function. The concept of testosterone supplementation (TST) in men with ED is reviewed. The authors utilize clinical vignettes to discuss the appropriate management of two clinical cases of men at different life stages who have ED in the setting of hypogonadism and propose a treatment algorithm. In patients of all ages, proper identification of the underlying pathophysiology of decreased libido and erectile function is paramount in choosing between the use of TST, phosphodiesterase type 5 inhibitors, or both, in the management of these disorders.Key words: Erectile dysfunction, Testosterone supplementation, Hypogonadism, Phosphodiesterase type 5 inhibitorsErectile dysfunction (ED) has emerged as an important marker of cardiovascular and overall health, independent of other known conventional risk factors. Because ED often precedes coronary artery disease (CAD) in half of affected subjects, it may be considered a harbinger of indolent cardiovascular pathology.^1,2 The modulation of erectile function by testosterone is well known,^3,4 and in men with both hypogonadism and ED a treatment strategy necessitating management of both conditions is required.Phosphodiesterase type 5 inhibitors (PDE5i) and testosterone supplementation therapy (TST) are established treatment strategies for ED and hypogonadism, respectively. Using a PDE5i in combination with TST has the potential for improving efficacy in men with concurrent ED and hypogonadism compared with the use of either agent alone. However, in light of the recent evidence associating testosterone with cardiovascular risk in elderly men,^5,6 TST should be used judiciously in the management of ED in older men.     

Genetic analysis of temperature-sensitive male sterilty in rice

The present study of genetic analysis is an attempt to precisely characterize diverse temperature-sensitive genic male-sterile (TGMS) lines so as to explore the possibilities of utilizing the most promising in large-scale hybrid seed production. Genetical studies revealed that the TGMS segregants derived from crosses involving TGMS lines ID24 and SA2 expressed differential fertility levels at low-temperature conditions. A majority of these progenies expressed transgressive segregation towards either sterility of fertility, causing instability of sterility and low reversibilty of fertility which may be due to large numbers of single-locus QTLs and their epistatic interactions. We identified two putative genes imparting temperature-sensitive male sterility after observing crosses involving diverse TGMS sources. To identify suitable molecular markers closely linked to the trait we used RAPD, AFLP and microsatellites which generated polymorphism through bulked segregant analysis. AFLP analysis using a smaller genome kit resulted in enormous polymorphism, out of which the combination EAA/MCAG amplified a 330-bp fragment, which closely segregated with the gene at a distance of 5.3 cM. This fragment was eluted for cloning and from the sequence a STS primer (TS200) was developed which produced a dominant polymorphism specific to TGMS. The microsatellite RM257, located earlier on chromosome 9, was linked with the TGMS trait in SA2 at a distance of 6.2 cM. RM257 produced a codominant polymorphism with 145-bp (sterile) and 132-bp (fertile) products. Both individually and collectively, the markers TS200 and RM257 located on either side of the TGMS locus are very useful for marker-assisted selection. Received: 10 April 1999 / Accepted: 29 July 1999     

Surface functionalization of nanobiomaterials for application in stem cell culture,tissue engineering,and regenerative medicine

Stem cell‐based approaches offer great application potential in tissue engineering and regenerative medicine owing to their ability of sensing the microenvironment and respond accordingly (dynamic behavior). Recently, the combination of nanobiomaterials with stem cells has paved a great way for further exploration. Nanobiomaterials with engineered surfaces could mimic the native microenvironment to which the seeded stem cells could adhere and migrate. Surface functionalized nanobiomaterial‐based scaffolds could then be used to regulate or control the cellular functions to culture stem cells and regenerate damaged tissues or organs. Therefore, controlling the interactions between nanobiomaterials and stem cells is a critical factor. However, surface functionalization or modification techniques has provided an alternative approach for tailoring the nanobiomaterials surface in accordance to the physiological surrounding of a living cells; thereby, enhancing the structural and functional properties of the engineered tissues and organs. Currently, there are a variety of methods and technologies available to modify the surface of biomaterials according to the specific cell or tissue properties to be regenerated. This review highlights the trends in surface modification techniques for nanobiomaterials and the biological relevance in stem cell‐based tissue engineering and regenerative medicine. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:554–567, 2016     

The Light Skin Allele of SLC24A5 in South Asians and Europeans Shares Identity by Descent

Skin pigmentation is one of the most variable phenotypic traits in humans. A non-synonymous substitution (rs1426654) in the third exon of SLC24A5 accounts for lighter skin in Europeans but not in East Asians. A previous genome-wide association study carried out in a heterogeneous sample of UK immigrants of South Asian descent suggested that this gene also contributes significantly to skin pigmentation variation among South Asians. In the present study, we have quantitatively assessed skin pigmentation for a largely homogeneous cohort of 1228 individuals from the Southern region of the Indian subcontinent. Our data confirm significant association of rs1426654 SNP with skin pigmentation, explaining about 27% of total phenotypic variation in the cohort studied. Our extensive survey of the polymorphism in 1573 individuals from 54 ethnic populations across the Indian subcontinent reveals wide presence of the derived-A allele, although the frequencies vary substantially among populations. We also show that the geospatial pattern of this allele is complex, but most importantly, reflects strong influence of language, geography and demographic history of the populations. Sequencing 11.74 kb of SLC24A5 in 95 individuals worldwide reveals that the rs1426654-A alleles in South Asian and West Eurasian populations are monophyletic and occur on the background of a common haplotype that is characterized by low genetic diversity. We date the coalescence of the light skin associated allele at 22–28 KYA. Both our sequence and genome-wide genotype data confirm that this gene has been a target for positive selection among Europeans. However, the latter also shows additional evidence of selection in populations of the Middle East, Central Asia, Pakistan and North India but not in South India.