Resistance of peripheral and sub-cortical somatosensory pathway to electrical noise

The somatosensory system is vulnerable to large amounts of noise distortion. But how does the central nervous system distinguish the peripheral inputs which carry information to the brain from that which does not possess information? To address this question we studied the effect of electrical stimulation of the median nerve on tactile spatial frequency perception in healthy subjects and Parkinson's disease (PD) patients. Subjects were categorized in two groups (healthy and PD patients) and were asked to report if a test tactile frequency pattern (TFP) was the same as the reference TFP given to the other hand. In each case stimulation was either present or absent on the median nerve of the hand holding the test pattern. We observed no impairment of tactile performance in the presence of electrical stimulation of the median nerve. This result together with previous work on direct stimulation of the somatosensory relay nucleus of the thalamus (Abbassian et al., Stereotact Funct Neurosurg 76: 19–28, 2001) in which the same result of no impairment of the tactile discrimination task was observed suggest a high degree of noise tolerance exists in the somatosensory pathway.     

Association of cell free mitochondrial DNA and caspase-1 expression with disease severity and ARTs efficacy in HIV infection

HIV infection is a global health concern. Current HIV-diagnostics provide information about the disease progression and efficacy of anti-retroviral therapies (ARVs), but this information is very limited and sometimes imprecise. Present study assessed the potential role of mononuclear cell (MNC) death, expression of caspases (1&3) and cell free mitochondrial DNA (CF mt-DNA) in HIV infected individuals. Apoptosis, cell-count, expression of caspases and CF mt-DNA were measured through flow cytometry and qPCR, respectively, in HIV infected individuals (n?=?120) divided in two groups i.e. ARVs-receiving (treated, n?=?87), ART-naïve (untreated, n?=?37) and healthy individuals (n?=?47). Data showed significant (p?<?0.0001) cell death in untreated individuals than treated and healthy individuals. CD4-positive T-cell percentage declined (p?<?0.0001) in untreated as compared to treated individuals. Caspase-1, an indicator of pyroptosis, and CF mt-DNA were also elevated in untreated HIV infected individuals. Untreated individuals when administered with ARVs showed improved CD4-positive T-cell percentage, lower caspase-1, CF mt-DNA and cell death. Data elucidated positive co-relation between cell death and CF mt-DNA in treated and untreated HIV infected individuals. While CD4-positive T-cell percentage was negatively correlated with caspase-1 expression and CF mt-DNA. Elevated levels of CF mt-DNA and caspase-1 in HIV infected individuals, positive correlation between cell death and CF mt-DNA, negative correlation of CD4-positive T-cell percentage with CF mt-DNA and caspase-1 expression clearly indicated the potential of CF mt-DNA and caspase-1 as a novel disease progression and ARTs effectiveness biomarkers in HIV.

     

Domain analyses of Usher syndrome causing Clarin-1 and GPR98 protein models

Usher syndrome is an autosomal recessive disorder that causes hearing loss, Retinitis Pigmentosa (RP) and vestibular dysfunction. It is clinically and genetically heterogeneous disorder which is clinically divided into three types i.e. type I, type II and type III. To date, there are about twelve loci and ten identified genes which are associated with Usher syndrome. A mutation in any of these genes e.g. CDH23, CLRN1, GPR98, MYO7A, PCDH15, USH1C, USH1G, USH2A and DFNB31 can result in Usher syndrome or non-syndromic deafness. These genes provide instructions for making proteins that play important roles in normal hearing, balance and vision. Studies have shown that protein structures of only seven genes have been determined experimentally and there are still three genes whose structures are unavailable. These genes are Clarin-1, GPR98 and Usherin. In the absence of an experimentally determined structure, homology modeling and threading often provide a useful 3D model of a protein. Therefore in the current study Clarin-1 and GPR98 proteins have been analyzed for signal peptide, domains and motifs. Clarin-1 protein was found to be without any signal peptide and consists of prokar lipoprotein domain. Clarin-1 is classified within claudin 2 super family and consists of twelve motifs. Whereas, GPR98 has a 29 amino acids long signal peptide and classified within GPCR family 2 having Concanavalin A-like lectin/glucanase superfamily. It was found to be consists of GPS and G protein receptor F2 domains and twenty nine motifs. Their 3D structures have been predicted using I-TASSER server. The model of Clarin-1 showed only α-helix but no beta sheets while model of GPR98 showed both α-helix and β sheets. The predicted structures were then evaluated and validated by MolProbity and Ramachandran plot. The evaluation of the predicted structures showed 78.9% residues of Clarin-1 and 78.9% residues of GPR98 within favored regions. The findings of present study has resulted in the three dimensional structure prediction and conserved domain analysis which will be quite beneficial in better understanding of molecular components, protein-protein interaction, clinical heterogeneity and pathophysiology of Usher syndrome.     

Comparisons of DNA marker-based genetic diversity with phenotypic estimates in maize grown in Pakistan

We compared DNA-based genetic diversity estimates with conventional estimates by investigating agronomically important traits in maize grown in the northwestern region of Pakistan. RAPD markers were used to characterize 10 commonly cultivated maize genotypes. The same material was tested for phenotypic variation of quantitative traits using replicated field trials. The genetic distances between pairs of genotypes using RAPD data were used to generate a similarity matrix and to construct a phenogram. Statistical analyses were carried out on the data obtained from field trials of all maize genotypes for days to 50% tasseling, days to 50% silking, plant height, ear height, grain yield, grain weight per cob, and ear length. Analysis of variance and single degree of freedom contrasts were performed on morphological data to examine the relationship between molecular-based clusters and agronomic traits. A molecular marker-based phenogram led to the grouping of all genotypes into four major clusters, some of which were distantly related. These clusters contained one to four genotypes. Analysis of variance showed significant variations among all genotypes for agronomic traits. The single degree of freedom contrasts between groups of genotypes indicated significant differences for most traits. Pair-wise comparisons between clusters were also significant. The two types of data correlated well, providing an opportunity for better choices for selection.     

Resistance of peripheral and sub-cortical somatosensory pathway to electrical noise

The somatosensory system is vulnerable to large amounts of noise distortion. But how does the central nervous system distinguish the peripheral inputs which carry information to the brain from that which does not possess information? To address this question we studied the effect of electrical stimulation of the median nerve on tactile spatial frequency perception in healthy subjects and Parkinson's disease (PD) patients. Subjects were categorized in two groups (healthy and PD patients) and were asked to report if a test tactile frequency pattern (TFP) was the same as the reference TFP given to the other hand. In each case stimulation was either present or absent on the median nerve of the hand holding the test pattern. We observed no impairment of tactile performance in the presence of electrical stimulation of the median nerve. This result together with previous work on direct stimulation of the somatosensory relay nucleus of the thalamus in which the same result of no impairment of the tactile discrimination task was observed suggest a high degree of noise tolerance exists in the somatosensory pathway.     

An overview of microwave hydrothermal carbonization and microwave pyrolysis of biomass

Biomass utilization has received much attention for production of high density solid fuels. Utilization of cheap and naturally available precursors through environmentally friendly and effective processes is an attractive and emerging research area. Pyrolysis and hydrothermal carbonization (HTC) are well-known technologies available for production of solid biofuel using conventional or microwave heating. Microwave heating is a simpler and more efficient heating method than conventional heating. This study presents a critical review on microwave pyrolysis and microwave HTC for solid fuel production in terms of yield and quality of products. Moreover, a brief summary of parameters of microwave pyrolysis and microwave HTC are discussed. The fuel, chemical, structural and thermal weight loss characteristics of solid fuels produced from different biomass are discussed and compared.     

Insect pollinator diversity in four forested ecosystems of southern Punjab,Pakistan

This study investigated pollinator assemblage diversity and richness in four forested ecosystems of southern Punjab, Pakistan, with different landscape types. Pirowal is situated in the plains of irrigated Punjab, Lal Suhanra is part of a sandy desert ecosystem, Ghazi Ghat is part of the Indus River delta, and Fort Munro is located in dry hilly mountains. A yearlong survey of pollinator populations was carried out in these four forested ecosystems from January to December of 2010. Fortnightly hand netting was performed for collecting flower-visiting insects whereas, pan traps of three colors (white, blue, and yellow) were deployed for collecting the data. A total of 8,812 individuals from two orders (Lepidoptera and Diptera) were observed, including 22 families and 154 species. Bees were the most abundant, with 4,502 individuals, and the most species-rich taxa, with 70 species in five families, followed by flies having 2,509 individuals and 51species in 10 families. Wasps were the least abundant with 1,801 individuals and 33 species in seven families. The assemblage structure of pollinator communities as visualized through rank abundance curves showed that there were many species with low abundance and only a few species with a much higher abundance. The most abundant species among the bees, in order, were Nomia sp.3, Megachile bicolor, and Colletes sp.3; among flies, Syrphus sp.2, Calliphoridae sp.1, and Empididae sp.4; and among wasps, Tiphiidae sp.1, Myzininae sp.2, and Scelionidae sp.1.     

Correlations among oligonucleotide repeats,nucleotide substitutions,and insertion–deletion mutations in chloroplast genomes of plant family Malvaceae

The co‐occurrence of mutational events including substitutions and insertions–deletions (InDels) with oligonucleotide repeats has previously been reported for a limited number of prokaryotic, eukaryotic, and organelle genomes. In this study, the correlations among these mutational events in chloroplast genomes of species in the eudicot family Malvaceae were investigated. This study also reported chloroplast genome sequences of Hibiscus mutabilis, Malva parviflora, and Malvastrum coromandelianum. These three genomes and 16 other publicly available chloroplast genomes from 12 genera of Malvaceae were used to calculate the correlation coefficients among the mutational events at family, subfamily, and genus levels. In these comparisons, chloroplast genomes were pairwise aligned to record the substitutions and the InDels in mutually exclusive, 250nucleotide long bins. Taking one among the two genomes as a reference, the coordinate positions of oligonucleotide repeats in the reference genome were recorded. The extent of correlations among repeats, substitutions, and InDels was calculated and categorized as follows: very weak (0.1–0.19), weak (0.20–0.29), moderate (0.30–0.39), and strong (0.4–0.69). The extent of correlations ranged 0.201–0.6 between “InDels and single‐nucleotide polymorphism (SNP)”, 0.182–0.513 between “InDels and repeat” and 0.055–0.403 between “SNPs and repeats”. At family‐ and subfamily‐level comparisons, 88%–96% of the repeats showed co‐occurrence with SNPs, whereas at the genus level, 23%–86% of the repeats co‐occurred with SNPs in same bins. Our findings support the previous hypothesis suggesting the use of oligonucleotide repeats as a proxy for finding the mutational hotspots.     

Design of a High-Resolution Metal–Insulator–Metal Plasmonic Refractive Index Sensor Based on a Ring-Shaped Si Resonator

In this paper, a high-resolution refractive index sensor is proposed based on a novel metal–insulator–metal plasmonic topology. The structure is based on a Si nano-ring located inside a circular cavity. It acts as an optical notch filter with a quality factor equal to 269. The proposed filter topology is numerically simulated using the finite difference time domain method. It is shown that the proposed filter can also act as a refractive index sensor with a sensitivity of 636 nm/RIU and a fairly high figure of merit (FoM) equal to 211.3 RIU⁻¹. It is shown that the sensor can easily detect a refractive index change of ± 0.001 for dielectrics whose refractive index is between 1 and 1.2. For the refractive index range of 1.33 to 1.52, the maximum FoM of the sensor is 191 RIU⁻¹. The simplicity of the design and its high resolution are the two main features of the proposed sensor which make it a good candidate for biomedical applications.

     

The role of glyceraldehyde 3-phosphate dehydrogenase (GapA-1) in <Emphasis Type="Italic">Neisseria meningitidis</Emphasis> adherence to human cells

Background  

Glyceraldehyde 3-phosphate dehydrogenases (GAPDHs) are cytoplasmic glycolytic enzymes, which although lacking identifiable secretion signals, have also been found localized to the surface of several bacteria (and some eukaryotic organisms); where in some cases they have been shown to contribute to the colonization and invasion of host tissues. Neisseria meningitidis is an obligate human nasopharyngeal commensal which can cause life-threatening infections including septicaemia and meningitis. N. meningitidis has two genes, gapA-1 and gapA-2, encoding GAPDH enzymes. GapA-1 has previously been shown to be up-regulated on bacterial contact with host epithelial cells and is accessible to antibodies on the surface of capsule-permeabilized meningococcal cells. The aims of this study were: 1) to determine whether GapA-1 was expressed across different strains of N. meningitidis; 2) to determine whether GapA-1 surface accessibility to antibodies was dependant on the presence of capsule; 3) to determine whether GapA-1 can influence the interaction of meningococci and host cells, particularly in the key stages of adhesion and invasion.