Proteomic identification and characterization of secreted N‐glycosylated NPC2 following cross‐linking of the high‐affinity receptor for IgE on mast cells

Allergen‐mediated cross‐linking of the high‐affinity receptor for IgE on mast cells triggers the release of diverse preformed and de novo synthesized immunoregulatory mediators that further the allergic response. A proteomic screen applied to the detection of proteins secreted by the model rat mast cell line, RBL‐2H3 (rat basophilic leukaemia, subline 2H3.1), led to the identification of the cholesterol‐binding glycoprotein, NPC2/RE1 (Niemann–Pick Type C2/epididymal secretory protein 1). Glycosylated NPC2 is secreted early in response to an IgE‐mediated stimulus and co‐localizes with the lysosomal membrane marker, CD63. NPC2 belongs to the ML (MD‐2‐related lipid‐recognition) protein family (155 members), which includes the Toll‐like receptor co‐factors, MD‐1 and MD‐2, and perhaps most interestingly, seven major house dust mite allergens of unknown function (including Der p 2 and Der f 2). Possible role(s) for the protein in the allergic response and future applications of this approach are discussed.     

The structure of the coiled-coil domain of Ndel1 and the basis of its interaction with Lis1, the causal protein of Miller-Dieker lissencephaly

Ndel1 and Nde1 are homologous and evolutionarily conserved proteins, with critical roles in cell division, neuronal migration, and other physiological phenomena. These functions are dependent on their interactions with the retrograde microtubule motor dynein and with its regulator Lis1--a product of the causal gene for isolated lissencephaly sequence (ILS) and Miller-Dieker lissencephaly. The molecular basis of the interactions of Ndel1 and Nde1 with Lis1 is not known. Here, we present a crystallographic study of two fragments of the coiled-coil domain of Ndel1, one of which reveals contiguous high-quality electron density for residues 10-166, the longest such structure reported by X-ray diffraction at high resolution. Together with complementary solution studies, our structures reveal how the Ndel1 coiled coil forms a stable parallel homodimer and suggest mechanisms by which the Lis1-interacting domain can be regulated to maintain a conformation in which two supercoiled alpha helices cooperatively bind to a Lis1 homodimer.     

Amino acid-based enantiomerically pure 3-substituted 1,4-benzodiazepin-2-ones: a new class of anti-ischemic agents

A series of 3-substituted 1,4-benzodiazepin-2-ones derived from S and R amino acids were evaluated for their anti-ischemic activity in vitro. Treatment with compounds 7h, 16, 9d, and 17 decreased the apoptotic neuronal number, however increased the neuronal viability. The compounds decreasing apoptosis could protect neurons from the ischemic injury. The difference in the activities of 1,4-benzodiazepin-2-ones derived from S- and R-amino acids is discussed and explained on the basis of molecular modeling studies.     

Intestinal Parasitosis in Relation to Anti-Retroviral Therapy,CD4+ T-cell Count and Diarrhea in HIV Patients

Intestinal parasitic infections are one of the major causes of diarrhea in human immunodeficiency virus (HIV) seropositive individuals. Antiretroviral therapy has markedly reduced the incidence of many opportunistic infections, but parasite-related diarrhea still remains frequent and often underestimated especially in developing countries. The present hospital-based study was conducted to determine the spectrum of intestinal parasitosis in adult HIV/AIDS (acquired immunodeficiency syndrome) patients with or without diarrhea with the levels of CD4⁺ T-cell counts. A total of 400 individuals were enrolled and were screened for intestinal parasitosis. Of these study population, 200 were HIV seropositives, and the remaining 200 were HIV uninfected individuals with or without diarrhea. Intestinal parasites were identified by using microscopy as well as PCR assay. A total of 130 (32.5%) out of 400 patients were positive for any kinds of intestinal parasites. The cumulative number of parasite positive patients was 152 due to multiple infections. A significant association of Cryptosporidium (P<0.001) was detected among individuals with CD4⁺ T-cell counts less than 200 cells/μl.     

Diversity and polymorphism in AHL-lactonase gene (aiiA) of Bacillus

To explore bacterial diversity for elucidating genetic variability in acylhomoserine lactone (AHL) lactonase structure, we screened 800 bacterial strains. It revealed the presence of a quorum quenching (QQ) AHL-lactonase gene (aiiA) in 42 strains. These 42 strains were identified using rrs (16S rDNA) sequencing as Bacillus strains, predominantly B. cereus. An in silico restriction endonuclease (RE) digestion of 22 AHL lactonase gene (aiiA) sequences (from NCBI database) belonging to 9 different genera, along with 42 aiiA gene sequences from different Bacillus spp. (isolated here) with 14 type II REs, revealed distinct patterns of fragments (nucleotide length and order) with four REs; AluI, DpnII, RsaI, and Tru9I. Our study reflects on the biodiversity of aiiA among Bacillus species. Bacillus sp. strain MBG11 with polymorphism (115Alanine > Valine) may confer increased stability to AHL lactonase, and can be a potential candidate for heterologous expression and mass production. Microbes with ability to produce AHL-lactonases degrade quorum sensing signals such as AHL by opening of the lactone ring. The naturally occurring diversity of QQ molecules provides opportunities to use them for preventing bacterial infections, spoilage of food, and bioremediation.     

Oxidative stress in zinc-induced dopaminergic neurodegeneration: implications of superoxide dismutase and heme oxygenase-1

The study was undertaken to investigate the effect of zinc (Zn) on glutathione S-transferase (GST) and superoxide dismutases (SOD) activities and on the expressions of cytosolic Cu, Zn-SOD (SOD1), mitochondrial Mn-SOD (SOD2), γ-glutamyl cysteine synthetase (γ-GCS) and heme oxygenase-1 (HO-1) in the nigrostriatal tissue of rats. Additionally, Zn-induced alterations in the neurobehavioral parameters, lipid peroxidation (LPO), striatal dopamine and its metabolites and tyrosine hydroxylase (TH) protein expression were measured to assess their correlations with the oxidative stress. Zn exposure reduced the locomotor activity, rotarod performance, striatal dopamine and its metabolites and TH protein expression. LPO, total SOD, SOD1 and SOD2 activities were increased while GST and catalase were reduced in a dose and time dependent manner. Expressions of SOD1 and HO-1 were increased while no change was observed in SOD2 and γ-GCS expressions. The results obtained suggest that Zn-induced augmentation of total SOD, SOD1, SOD2 and HO-1 was associated with increased oxidative stress and neurodegenerative indexes indicating the involvement of both cytosolic and mitochondrial machinery in Zn-induced oxidative stress leading to dopaminergic neurodegeneration.     

Patterns of tree phenological diversity in dry tropics

Recent phenological studies in tropical deciduous forests revealed a mosaic of vegetation composed of several pheno-phases that are evolved as an adaptation by the species to overcome seasonal drought in different ways. These pheno-phases represent extent of annual deciduousness (～leaflessness) and triggering factors for buds break (e.g. vegetative and flower). Thus, studying patterns of various pheno-phases (phonological diversity) in tropical forest have been thought to provide a potential tool to address critical questions related to climate change modeling and monitoring. In tropics, tree species represent a gradient of deciduousness (from leaf-exchanging species to >6 months deciduous species) and flowering initiation (breaking of flower buds in various part of annual cycle). Both processes are mostly triggered by variation in day length and/or temperature during late dry season/autumn, and/or first significant rain during rainy season. In addition, few factors like drought induced leaf fall and sporadic winter rains are supposed to affect these processes temporarily. Besides, the abundances of pheno-phases (i.e. leafing and flowering) also vary among tropical deciduous forest trees. Presence of such variations in tropical tree pheno-phases and their abundances are reported to vary due to micro-climatic variables and has specific implications in tropical forests. Present paper discusses the existing information on various pheno-phases and their abundances in tropical forests and role of climatic factors on tree phonological diversity. Further, we emphasized the need to develop predicting understanding of impending climatic change (i.e. precipitation and temperature) on diversity of pheno-phases by collecting long-term data on tree pheno-phases through a network of phonological stations in dry tropics.