Alkaline protease production by Basidiobolus (N.C.L. 97.1.1): effect of 'darmform' morphogenesis and cultural conditions on enzyme production and preliminary enzyme characterization

A strain of Basidiobolus (N.C.L. 97.1.1) was isolated from plant detritus which secreted alkaline protease optimally active at pH 10.0. It is the first report of a protease from Basidiobolus, which is stable to and active under high alkaline conditions. When incubated under stationary conditions in broth cultures containing salts such as ammonium chloride, 'darmform' morphogenesis was readily induced through enlargement and internal division of the hyphal segments. Secretion of high activity alkaline protease was obtained in cultures initiated with darmform morphogenesis whereas cultures initiated from mycelial inocula grew as large pellets in submerged cultures, with little or no protease secretion. Cultural conditions favoring alkaline protease secretion have been optimized and a preliminary characterization of the enzyme is presented. Compatibility of the alkaline protease with commercial detergents as well as its potential application in recovering silver from spent photographic films have also been investigated.     

Synthesis and analysis of the membrane proximal external region epitopes of HIV‐1

The membrane proximal external region (MPER) of gp41 abuts the viral membrane at the base of HIV‐1 envelope glycoprotein spikes. The MPER is highly conserved and is rich in Trp and other lipophilic residues. The MPER is also required for the infection of host cells by HIV‐1 and is the target of the broadly neutralizing antibodies, 4E10, 2F5, and Z13e1. These neutralizing antibodies are valuable tools for understanding relevant conformations of the MPER and for studying HIV‐1 neutralization, but multiple approaches used to elicit MPER binding antibodies with similar neutralization properties have failed. Here we report our efforts to mimic the MPER using linear as well as constrained peptides. Unnatural amino acids were also introduced into the core epitope of 4E10 to probe requirements of antibody binding. Peptide analogs with C‐terminal Api or Aib residues designed to be helical transmembrane (TM) domain surrogates exhibit enhanced binding to the 4E10 and Z13e1 antibodies. However, we find that placement of constrained amino acids at nonbinding sites within the core epitope significantly reduce binding. These results are relevant to an understanding of native MPER structure on HIV‐1, and form a basis for a chemical synthesis approach to mimic MPER stricture and to construct an MPER‐based vaccine. Copyright © 2010 European Peptide Society and John Wiley & Sons, Ltd.     

Prevalence and Factors Associated with Road Traffic Crash among Taxi Drivers in Mekelle Town,Northern Ethiopia, 2014: A Cross Sectional Study

Objectives

The 2013 World Health Organization Status Report on Road Safety estimated that approximately 1.24 million deaths occur annually due to road traffic crashes with most of the burden falling on low- and middle-income countries. The objective of this research is to study the prevalence of road traffic crashes in Mekelle, Tigray, Northern Ethiopia and to identify risk factors with the ultimate goal of informing prevention activities and policies.

Methods

This study used a cross-sectional design to measure the prevalence and factors associated with road traffic crashes among 4-wheeled minibus (n = 130) and 3-wheeled Bajaj (n = 582) taxi drivers in Mekelle, Ethiopia. Bivariate and multivariate logistic regression were used to evaluate the association between risk factors and drivers’ involvement in a road traffic crash within the 3 years prior to the survey.

Findings

Among the 712 taxi drivers, 26.4% (n = 188) of them reported involvement in a road traffic crash within the past 3 years. Drivers who listened to mass media had decreased likelihood of road traffic crash involvement (AOR = 0.51, 0.33–0.78), while speedy driving (AOR = 4.57, 3.05–7.44), receipt of a prior traffic punishment (AOR = 4.57, 2.67–7.85), and driving a mechanically faulty taxi (AOR = 4.91, 2.81–8.61) were strongly associated with road traffic crash involvement. Receiving mobile phone calls while driving (AOR = 1.91, 1.24–2.92) and history of alcohol use (AOR = 1.51, 1.00–2.28) were also associated with higher odds of road traffic crash involvement.

Conclusion

The results of this study show that taxi drivers in Mekelle habitually place themselves at increased risk of road traffic crashes by violating traffic laws, especially related to speedy driving, mobile phone use, and taxi maintenance. This research can be used to support re-evaluation of the type, severity, and enforcement of traffic violation penalties.     

Does CK2 affect flowering time by modulating the autonomous pathway in Arabidopsis?

CK2 (Casein kinase II), a ubiquitous Ser/Thr kinase, affects multiple developmental and stress response pathways in Arabidopsis, including flowering time under both long- and short-day conditions through the photoperiod and autonomous pathways. CK2 phosphorylates central clock components, CCA1 and LHY, to modulate circadian clock that regulates flowering time through the photoperiod pathway. However, how CK2 regulates flowering time through the autonomous pathway is still unknown. Analyses of phosphorylation sites using several prediction softwares show that most of the autonomous pathway components have multiple CK2 phosphorylation sites. CK2 might phosphorylate any or all of these components to modulate their activity/stability resulting in altered expression of FLC that drives flowering time through the autonomous pathway.     

<Emphasis Type="Italic">Syzygium aromaticum</Emphasis> extract mediated,rapid and facile biogenic synthesis of shape-controlled (3D) silver nanocubes

The synthesis of metal nano materials with controllable geometry has received extensive attention of researchers from the past decade. In this study, we report an unexplored new route for rapid and facile biogenic synthesis of silver nanocubes (AgNCs) by systematic reduction of silver ions with crude clove (Syzygium aromaticum) extract at room temperature. The formation and plasmonic properties of AgNCs were observed and the UV–vis spectra show characteristic absorption peak of AgNCs with broaden region at 430 nm along with the intense (124), (686), (454) and (235) peak in X-ray diffraction pattern confirmed the formation and crystallinity of AgNCs. The average size of AgNC cubes were found to be in the range of ~80 to 150 nm and it was confirmed by particles size distribution, scanning and transmission electron microscopy with elemental detection by EDAX. Further FTIR spectra provide the various functional groups present in the S. aromaticum extract which are supposed to be responsible and participating in the reaction for the synthesis of AgNCs. The AgNCs casted over glass substrate show an electrical conductivity of ~0.55 × 10⁶ S/m demonstrating AgNCs to be a potential next generation conducting material due to its high conductivity. This work provides a novel and effective approach to control the shape of silver nanomaterial for impending applications. The current synthesis mode is eco-friendly, low cost and promises different potential applications such as biosensing, nanoelectronics, etc.     

Glycopeptides as versatile tools for glycobiology

This review describes the recent advances in the field of glycopeptide and small glycoprotein synthesis. The strategies covered include chemical and chemoenzymatic synthesis, native chemical ligation (NCL), and expressed chemical ligation. The importance of glycopeptide synthesis is exemplified by giving the reader an overview of how versatile and important these well-defined glycopeptides are as tools in glycobiology.     

A High Throughput Protein Microarray Approach to Classify HIV Monoclonal Antibodies and Variant Antigens

In recent years, high throughput discovery of human recombinant monoclonal antibodies (mAbs) has been applied to greatly advance our understanding of the specificity, and functional activity of antibodies against HIV. Thousands of antibodies have been generated and screened in functional neutralization assays, and antibodies associated with cross-strain neutralization and passive protection in primates, have been identified. To facilitate this type of discovery, a high throughput-screening tool is needed to accurately classify mAbs, and their antigen targets. In this study, we analyzed and evaluated a prototype microarray chip comprised of the HIV-1 recombinant proteins gp140, gp120, gp41, and several membrane proximal external region peptides. The protein microarray analysis of 11 HIV-1 envelope-specific mAbs revealed diverse binding affinities and specificities across clades. Half maximal effective concentrations, generated by our chip analysis, correlated significantly (P<0.0001) with concentrations from ELISA binding measurements. Polyclonal immune responses in plasma samples from HIV-1 infected subjects exhibited different binding patterns, and reactivity against printed proteins. Examining the totality of the specificity of the humoral response in this way reveals the exquisite diversity, and specificity of the humoral response to HIV.     

Role of Small Subunit in Mediating Assembly of Red-type Form I Rubisco

Ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) is the key enzyme involved in photosynthetic carbon fixation, converting atmospheric CO₂ to organic compounds. Form I Rubisco is a cylindrical complex composed of eight large (RbcL) subunits that are capped by four small subunits (RbcS) at the top and four at the bottom. Form I Rubiscos are phylogenetically divided into green- and red-type. Some red-type enzymes have catalytically superior properties. Thus, understanding their folding and assembly is of considerable biotechnological interest. Folding of the green-type RbcL subunits in cyanobacteria is mediated by the GroEL/ES chaperonin system, and assembly to holoenzyme requires specialized chaperones such as RbcX and RAF1. Here, we show that the red-type RbcL subunits in the proteobacterium Rhodobacter sphaeroides also fold with GroEL/ES. However, assembly proceeds in a chaperone-independent manner. We find that the C-terminal β-hairpin extension of red-type RbcS, which is absent in green-type RbcS, is critical for efficient assembly. The β-hairpins of four RbcS subunits form an eight-stranded β-barrel that protrudes into the central solvent channel of the RbcL core complex. The two β-barrels stabilize the complex through multiple interactions with the RbcL subunits. A chimeric green-type RbcS carrying the C-terminal β-hairpin renders the assembly of a cyanobacterial Rubisco independent of RbcX. Our results may facilitate the engineering of crop plants with improved growth properties expressing red-type Rubisco.