Influence of HDL-cholesterol-elevating drugs on the in vitro activity of the HDL receptor SR-BI

Treatment of atherosclerotic disease often focuses on reducing plasma LDL-cholesterol or increasing plasma HDL-cholesterol. We examined in vitro the effects on HDL receptor [scavenger receptor class B type I (SR-BI)] activity of three classes of clinical and experimental plasma HDL-cholesterol-elevating compounds: niacin, fibrates, and HDL376. Fenofibrate (FF) and HDL376 were potent (IC(50) approximately 1 microM), direct inhibitors of SR-BI-mediated lipid transport in cells and in liposomes reconstituted with purified SR-BI. FF, a prodrug, was a more potent inhibitor of SR-BI than an activator of peroxisome proliferator-activated receptor alpha, a target of its active fenofibric acid (FFA) derivative. Nevertheless, FFA, four other fibrates (clofibrate, gemfibrozil, ciprofibrate, and bezafibrate), and niacin had little, if any, effect on SR-BI, suggesting that they do not directly target SR-BI in vivo. However, similarities of HDL376 treatment and SR-BI gene knockout on HDL metabolism in vivo (increased HDL-cholesterol and HDL particle sizes) and structure-activity relationship analysis suggest that SR-BI may be a target of HDL376 in vivo. HDL376 and other inhibitors may help elucidate SR-BI function in diverse mammalian models and determine the therapeutic potential of SR-BI-directed pharmaceuticals.     

Relaxin's induction of metalloproteinases is associated with the loss of collagen and glycosaminoglycans in synovial joint fibrocartilaginous explants

Diseases of specific fibrocartilaginous joints are especially common in women of reproductive age, suggesting that female hormones contribute to their etiopathogenesis. Previously, we showed that relaxin dose-dependently induces matrix metalloproteinase (MMP) expression in isolated joint fibrocartilaginous cells. Here we determined the effects of relaxin with or without beta-estradiol on the modulation of MMPs in joint fibrocartilaginous explants, and assessed the contribution of these proteinases to the loss of collagen and glycosaminoglycan (GAG) in this tissue. Fibrocartilaginous discs from temporomandibular joints of female rabbits were cultured in medium alone or in medium containing relaxin (0.1 ng/ml) or beta-estradiol (20 ng/ml) or relaxin plus beta-estradiol. Additional experiments were done in the presence of the MMP inhibitor GM6001 or its control analog. After 48 hours of culture, the medium was assayed for MMPs and the discs were analyzed for collagen and GAG concentrations. Relaxin and beta-estradiol plus relaxin induced the MMPs collagenase-1 and stromelysin-1 in fibrocartilaginous explants--a finding similar to that which we observed in pubic symphysis fibrocartilage, but not in articular cartilage explants. The induction of these proteinases by relaxin or beta-estradiol plus relaxin was accompanied by a loss of GAGs and collagen in joint fibrocartilage. None of the hormone treatments altered the synthesis of GAGs, suggesting that the loss of this matrix molecule probably resulted from increased matrix degradation. Indeed, fibrocartilaginous explants cultured in the presence of GM6001 showed an inhibition of relaxin-induced and beta-estradiol plus relaxin-induced collagenase and stromelysin activities to control baseline levels that were accompanied by the maintenance of collagen or GAG content at control levels. These findings show for the first time that relaxin has degradative effects on non-reproductive synovial joint fibrocartilaginous tissue and provide evidence for a link between relaxin, MMPs, and matrix degradation.     

Physiological and genetic characterization of rice nitrogen fixer PGPR isolated from rhizosphere soils of different crops

Aims

We aimed to identify plant growth-promoting rhizobacteria that could be used to develop a biofertilizer for rice.

Methods

To obtain plant growth-promoting rhizobacteria, rhizosphere soils from different crops (rice, wheat, oats, crabgrass, maize, ryegrass, and sweet potato) were inoculated to rice plants. In total, 166 different bacteria were isolated and their plant growth-promoting traits were evaluated in terms of colony morphology, indole-3-acetic acid production, acetylene reduction activity, and phosphate solubilization activity. Moreover, genetic analysis was carried out to evaluate their phylogenetic relationships based on 16S rRNA sequence data.

Results

Strains of Bacillus altitudinis, Pseudomonas monteilii, and Pseudomonas mandelii formed associations with rice plants and fixed nitrogen. A strain of Rhizobium daejeonense showed nitrogen fixation activity in an in vitro assay and in vivo. Strains of B. altitudinis and R. daejeonense derived from rice rhizosphere soil, strains of P. monteilii and Enterobacter cloacae derived from wheat rhizosphere soil, and a strain of Bacillus pumilus derived from maize rhizosphere soil significantly promoted rice plant growth.

Conclusions

These methods are effective to identify candidate species that could be developed as biofertilizers for target crops.     

Silicon alleviates arsenic-induced toxicity in wheat through vacuolar sequestration and ROS scavenging

Arsenic (As) is a phytotoxic element causing health hazards. This work investigates whether and how silicon (Si) alleviates As toxicity in wheat. The addition of Si under As-stress significantly improved morphophysiological characteristics, total protein, and membrane stability compared to As-stressed plants, suggesting that Si does have critical roles in As detoxification in wheat. Analysis of arsenate reductase activity and phytosiderophore (PS) release reveals their no involvement in the Si-mediated alleviation of As in wheat. Furthermore, Si supplementation in As-stressed plants showed a significant increase of As in roots but not in shoots compared with the plants grown under As stress. Further, gene expression analysis of two chelating molecules, TaPCS1 (phytochelatin synthase) and TaMT1 (metallothionein synthase) showed significant induction due to Si application under As stress compared with As-stressed plants. It is consistent with the physiological observations and suggests that alleviation of As toxicity in rice might be associated with As sequestration in roots leading to reduced As translocation in shoots. Furthermore, increased catalase, peroxidase, and glutathione reductase activities in roots imply the active involvement of reactive oxygen species scavenging for protecting wheat plants from As-induced oxidative injury. The study provides mechanistic evidence on the beneficial effect of Si on As toxicity in wheat plants.     

Pol II promoter prediction using characteristic 4-mer motifs: a machine learning approach

Background  

Eukaryotic promoter prediction using computational analysis techniques is one of the most difficult jobs in computational genomics that is essential for constructing and understanding genetic regulatory networks. The increased availability of sequence data for various eukaryotic organisms in recent years has necessitated for better tools and techniques for the prediction and analysis of promoters in eukaryotic sequences. Many promoter prediction methods and tools have been developed to date but they have yet to provide acceptable predictive performance. One obvious criteria to improve on current methods is to devise a better system for selecting appropriate features of promoters that distinguish them from non-promoters. Secondly improved performance can be achieved by enhancing the predictive ability of the machine learning algorithms used.     

Template synthesis of novel carboxamide dinuclear copper (II) complex: spectral characterization and reactivity towards calf-thymus DNA

Dinuclear complexes Bis [aqua 1,8-(1,2-dicarboxamido benzene) 3,6-diazaoctane copper (II)/nickel (II)] tetrachloride (1 and 2) were synthesized by a two component one-pot metal template condensation between phthalic anhydride and 1,8-diamino 3,6-diazaoctane. Elemental analysis, molar conductance measurements, electronic absorption, infra-red, electron paramagnetic resonance, nuclear magnetic resonance, atomic absorption, and electron spray mass spectral studies have been performed to probe the nature and structure of the complexes. The interaction of copper (II) complex with calf thymus (CT-DNA) has been studied by using absorption, emission and circular dichoric spectral methods, viscometry, and cyclic voltammetry. A strong hyperchromism along with a red shift in UV bands and hypochromism in the ligand field band of the complex 1 on interaction with CT-DNA imply a covalent mode of DNA binding. This is further confirmed by studying the reactivity of complex 1 using circular dichroism and viscosity measurements. The variation in relative emission intensity of DNA-bound ethidium bromide observed upon treatment with the complex 1 parallel the trend of DNA binding studies. Cyclic voltammetry studies reveal that the complex 1 prefers to bind to DNA in Cu(II) rather than Cu(I) oxidation state.     

Platanic Acid-Aryl Enones as Potential Anticancer Compounds: Synthesis and Biological Profiling against Breast,Prostate and Lung Cancer Cell Lines

A series of rationally designed platanic acid-based compounds derived from naturally occurring betulinic acid were synthesized through a sequence of Lemieux-Johnson oxidation and Aldol condensation reaction. All the compounds were screened for cytotoxicity against a panel of human cancer and normal cell lines using MTT assay. From the biological data, it was observed that some of these semi-synthetic congeners exhibited potent biological profiles compared to platanic acid. One of the compounds with the p-tolyl substitution was found to be most active in this study, and its cytotoxicity against two of the cell lines, MDA-MB 231 and A-549 were in tune with the standard compound, 5-fluorouracil.     

An investigation of enumeration and DNA partitioning in Bacillus subtilis L-form bacteria

R.N. WATERHOUSE, E.J. ALLAN, F. AMIJEE, V.J. UNDRILL AND L.A. GLOVER. 1994. Cell numbers of two morphogenic forms of Bacillus subtilis (the cell-walled parental and the derived stable cell wall-deficient L-form) have been compared by two methods: DNA hybridization (i.e. deduced genome numbers) and viable cell counts (i.e. number of colony-forming units (cfu)). The DNA hybridization method was shown to be a reliable and reproducible method for estimating genome numbers. Comparison of different L-form populations showed that the two methods of enumeration gave different values, with the deduced genome numbers much higher (by several orders of magnitude) than cell numbers deduced from viable cell counts. In contrast, when a culture of the cell-walled form was enumerated, the discrepancy between the two methods was low (by a factor of about 6) The combination of a high number of L-form genomes detected by DNA hybridization and a relatively low number of cfu was thought to be a consequence of a diminished co-ordination between the DNA replication and cell division processes in L-form bacteria. This suggestion was further substantiated by assessing the stability of plasmid pPL608 in a transformed B. subtilis L-form cell line, where even in the presence of continued kanamycin selection, 25% of the population lost kanamycin resistance. The results are discussed with particular reference to cell division in cell wall-deficient, stable L-form bacteria.     

Antileishmanial potential of fused 5-(pyrazin-2-yl)-4H-1,2,4-triazole-3-thiols: Synthesis,biological evaluations and computational studies

A series of newer 1,2,4-triazole-3-thiol derivatives 5(a–m) and 6(a–i) containing a triazole fused with pyrazine moiety of pharmacological significance have been synthesized. All the synthesized compounds were screened for their in vitro antileishmanial and antioxidant activities. Compounds 5f (IC₅₀ = 79.0 µM) and 6f (IC₅₀ = 79.0 µM) were shown significant antileishmanial activity when compared with standard sodium stibogluconate (IC₅₀ = 490.0 µM). Compounds 5b (IC₅₀ = 13.96 µM) and 6b (IC₅₀ = 13.96 µM) showed significant antioxidant activity. After performing molecular docking study and analyzing overall binding modes it was found that the synthesized compounds had potential to inhibit L. donovani pteridine reductase 1 enzyme. In silico ADME and metabolic site prediction studies were also held out to set an effective lead candidate for the future antileishmanial and antibacterial drug discovery initiatives.