Novel isoforms of proteinaceous α-amylase inhibitor (α-AI) from seed extract of Albizia lebbeck

Proteinaceous inhibitors of digestive α-amylase occur naturally in leguminous seeds and find applications in agriculture and clinical studies. We have detected and isolated eight novel α-amylase inhibitor isoforms in the seed extract of Albizia lebbeck. They are designated as AL-αAI-1 to AL-αAI-8. These isoforms specifically inhibit human salivary α-amylase and porcine pancreatic α-amylase. The occurrence and profile of α-amylase inhibitor isoforms were revealed by 7 % native-PAGE containing 0.1 % starch. The apparent molecular weights of native bands of AL-αAIs were 97.4, 68.6, 61.0, 57.2, 56.0, 54.7, 51.1, and 47.7 kDa, respectively. Partial purification of potent α-amylase inhibitor was achieved using ammonium sulfate fractionation and gel filtration chromatography on G-100 Sephadex column followed by preparative gel electrophoresis. SDS-PAGE analysis of partially purified AL-αAI showed two polypeptide bands of ~35.8 and ~32.6 kDa. All these isoforms showed effective resistance to in vitro proteolysis by pepsin, trypsin, and chymotrypsin. These inhibitors are stable over a wide range of pH and temperature and have optimum activity at pH 7 and at 37 °C. The finding and information obtained in the present investigation about novel isoforms of α-amylase inhibitors from A. lebbeck could be important and may find applications in clinical studies to modulate starch digestion and glycemic index.     

New bioactive macrocyclic diterpenoids from Jatropha multifida

Two new macrocyclic diterpenoids, multifidanol (1) and multifidenol (2) along with several known compounds have been isolated from the stem of Jatropha multifida. The structures of the new compounds were established from the extensive studies of their 1D and 2D NMR spectra. The cytotoxic and antimicrobial activities of these two constituents were examined.     

Effect of quercetin on the amiloride–bovine serum albumin interaction using spectroscopic methods,molecular docking and chemometric approaches

The effect of quercetin flavonoid (QUE), on the binding interaction of antihypertensive drug, amiloride (AMI) with bovine serum albumin (BSA) was investigated in this study. Spectroscopic methods such as steady‐state, synchronous, three‐dimensional fluorescence, and circular dichroism spectroscopy were employed to study the interaction. Fluorescence data were analyzed using the Stern–Volmer equation and a static quenching process was found to be involved in the formation of AMI–BSA and QUE–BSA complexes and were in good agreement with the thermodynamic study. The thermodynamic parameters illustrated that the process is spontaneous and enthalpy driven. Hydrophobicity is acting as the primary force in the binding interaction. Fluorescence spectral data were resolved using a multivariate curve resolution‐alternating least squares method (MCR–ALS). Site marker and molecular docking studies confirmed the binding site of AMI on BSA, i.e. site II. The binding distance between amino acid of BSA and AMI was calculated and found to be 2.18 nm which indicated that energy transfer has occurred from an amino acid of BSA to AMI. The binding affinity of AMI to BSA was found to be reduced in the presence of QUE, which may lead to the poor distribution of AMI at the desired site.     

Design, synthesis and pharmacological evaluation of conformationally restricted N-arylsulfonyl-3-aminoalkoxy indoles as a potential 5-HT6 receptor ligands

A series of novel conformationally restricted N(1)-arylsulfonyl-3-aminoalkoxy indoles were designed and synthesized as 5-HT(6) receptor (5-HT(6)R) ligands. Many of the synthesized compounds have moderate in vitro-binding affinities at 5-HT(6)R. The lead compound 8b (% inhibition?=?97.2 at 1 μM) from this series has good pharmacokinetic profile in male Wister rats and is active in animal model of cognition like Morris water maze. The details of chemistry, SAR, pharmacokinetics and pharmacological data constitute the subject matter of this report.     

Risk factors for severe outcomes following 2009 influenza A (H1N1) infection: a global pooled analysis

Background

Since the start of the 2009 influenza A pandemic (H1N1pdm), the World Health Organization and its member states have gathered information to characterize the clinical severity of H1N1pdm infection and to assist policy makers to determine risk groups for targeted control measures.

Methods and Findings

Data were collected on approximately 70,000 laboratory-confirmed hospitalized H1N1pdm patients, 9,700 patients admitted to intensive care units (ICUs), and 2,500 deaths reported between 1 April 2009 and 1 January 2010 from 19 countries or administrative regions—Argentina, Australia, Canada, Chile, China, France, Germany, Hong Kong SAR, Japan, Madagascar, Mexico, the Netherlands, New Zealand, Singapore, South Africa, Spain, Thailand, the United States, and the United Kingdom—to characterize and compare the distribution of risk factors among H1N1pdm patients at three levels of severity: hospitalizations, ICU admissions, and deaths. The median age of patients increased with severity of disease. The highest per capita risk of hospitalization was among patients <5 y and 5–14 y (relative risk [RR] = 3.3 and 3.2, respectively, compared to the general population), whereas the highest risk of death per capita was in the age groups 50–64 y and ≥65 y (RR = 1.5 and 1.6, respectively, compared to the general population). Similarly, the ratio of H1N1pdm deaths to hospitalizations increased with age and was the highest in the ≥65-y-old age group, indicating that while infection rates have been observed to be very low in the oldest age group, risk of death in those over the age of 64 y who became infected was higher than in younger groups. The proportion of H1N1pdm patients with one or more reported chronic conditions increased with severity (median = 31.1%, 52.3%, and 61.8% of hospitalized, ICU-admitted, and fatal H1N1pdm cases, respectively). With the exception of the risk factors asthma, pregnancy, and obesity, the proportion of patients with each risk factor increased with severity level. For all levels of severity, pregnant women in their third trimester consistently accounted for the majority of the total of pregnant women. Our findings suggest that morbid obesity might be a risk factor for ICU admission and fatal outcome (RR = 36.3).

Conclusions

Our results demonstrate that risk factors for severe H1N1pdm infection are similar to those for seasonal influenza, with some notable differences, such as younger age groups and obesity, and reinforce the need to identify and protect groups at highest risk of severe outcomes. Please see later in the article for the Editors'' Summary     

Bacillus subtillis RTSBA6 6.00, a new strain isolated from gut of Helicoverpa armigera (Lepidoptera: Noctuidae) produces chymotrypsin-like proteases

Exploring bacterial communities with proteolytic activity from the gut of the Helicoverpa armigera (Hubner) (Lepidoptera: Noctuidae) insect pests was the purpose of this study. As initial efforts to achieve this goal here we report the isolation of new Bacillus subtillis RTSBA6 6.00 strain from the gut of H. armigera and demonstrated as proteases producer. Zymographic analysis revealed 12 proteolytic bands with apparent molecular weights ranging from 20 to 185 kDa. Although some activity was detected at acidic pH, the major activity was observed at slight alkaline pH (7.8). The optimum temperature was found to be 35 °C with complete loss of activity at 70 °C. All proteases were completely inactivated by PMSF (phenylmethylsulfonyl fluoride) and TPCK (N-tosyl-l-phenylalanine chloromethyl ketone), suggesting that proteases secreted by B. subtillis RTSBA6 6.00 belong to serine proteases class with chymotrypsin-like activity. The occurrence of protease producing bacterial community in the gut of the H. armigera advocates its probable assistance to insect in proteinaceous food digestion and adaptation to protease inhibitors of host plants.     

Biofilm formation by Candida albicans on various prosthetic materials and its fluconazole sensitivity: a kinetic study

Candida albicans has the ability to colonize various materials used in prostheses. In this report, we have studied the kinetics of biofilm formation on prosthetic materials and their susceptibility to fluconazole at various stages of development. Results indicated that C. albicans efficiently adheres to and colonizes polystyrene, polyvinylchloride, silicon, and polycarbonate surfaces. Candida albicans biofilm formation was observed to be both strain- and substrate dependent. Adhesion of cells to solid substrates was found sufficient to induce fluconazole resistance. Drug susceptibility at different stages of biofilm growth showed that Candida biofilms on these substrates are highly resistant to fluconazole. The study focuses on the limitations of fluconazole to combat biofilm-related infections and emphasizes the need for better therapeutic strategies against prosthesis-associated C. albicans infections.     

Granulosa Cell Apoptosis Induced by a Novel FSH Binding Inhibitory Peptide From Human Ovarian Follicular Fluid

Pituitary gonadotropins, follicle-stimulating hormone and luteinizing hormone, are the key regulators of ovarian folliculogenesis; these are known to be directly or indirectly modulated by many intraovarian factors. Our group has identified and studied one such novel peptide from human ovarian follicular fluid. Its partial N-terminal eight amino acid sequence has been deduced, referred to as octapeptide (OP). OP induces follicular atresia in mice and interferes with normal ovarian function in non-human primates, this action being similar to the native peptide. Thus, in this study, an attempt has been made to elucidate the mechanism of action of the synthetic OP by studying the pathway of follicular atresia in mouse ovary. Changes in granulosa cells were studied using various apoptotic markers by flow cytometry and immunohistochemistry. An increase in apoptotic cell population in atretic- and peptide-treated groups was observed compared with normal controls. Interestingly, both these groups exhibited differences in the apoptotic pathway. Results showed that the mitochondrial pathway was predominant in the atretic group, whereas the Fas-FasL pathway was predominant in the peptide-treated groups. The ultrastructural study also showed apoptotic changes in the OP-treated and atretic groups; the pattern of apoptosis differed at the subcellular level. (J Histochem Cytochem 56:961–968, 2008)