SMAD4 contributes to chondrocyte and osteocyte development

Different cellular and molecular mechanisms contribute to chondrocyte and osteocyte development. Although vital roles of the mothers against decapentaplegic homolog 4 (also called ‘SMAD4’) have been discussed in different cancers and stem cell‐related studies, there are a few reviews summarizing the roles of this protein in the skeletal development and bone homeostasis. In order to fill this gap, we discuss the critical roles of SMAD4 in the skeletal development. To this end, we review the different signalling pathways and also how SMAD4 defines stem cell features. We also elaborate how the epigenetic factors—ie DNA methylation, histone modifications and noncoding RNAs—make a contribution to the chondrocyte and osteocyte development. To better grasp the important roles of SMAD4 in the cartilage and bone development, we also review the genotype‐phenotype correlation in animal models. This review helps us to understand the importance of the SMAD4 in the chondrocyte and bone development and the potential applications for therapeutic goals.     

Epimers from the leaves of Calophyllum inophyllum

The ethanolic extract of the fresh leaves of Calophyllum inophyllum afforded a pair of new epimers named as inophynone and isoinophynone. Their structures were elucidated with the aid of spectroscopic techniques. Some known constituents, cholesterol, friedelin, canophyllol and canophyllic acid, were also isolated from the same source.     

Imaging nanometer domains of beta-adrenergic receptor complexes on the surface of cardiac myocytes

The contraction of cardiac myocytes is initiated by ligand binding to adrenergic receptors contained in nanoscale multiprotein complexes called signalosomes. The composition and number of functional signalosomes within cardiac myocytes defines the molecular basis of the response to adrenergic stimuli. For the first time, we demonstrated the ability of near-field scanning optical microscopy to visualize beta-adrenergic receptors at the nanoscale in situ. On H9C2 cells, mouse neonatal and mouse embryonic cardiac myocytes, we showed that functional receptors are organized into multiprotein domains of approximately 140 nm average diameter. Colocalization experiments in primary cells at the nanometer scale showed that 15-20% of receptors were preassociated in caveolae. These nanoscale complexes were sufficient to effect changes in ligand-induced contraction rate without the requirement for substantial changes in receptor distribution in the cellular membrane. Using fluorescence intensities associated with these nanodomains, we estimated the receptor density within the observed nanometer features and established a lower limit for the number of receptors in the signalosome.     

Interaction with coxsackievirus and adenovirus receptor, but not with decay-accelerating factor (DAF), induces A-particle formation in a DAF-binding coxsackievirus B3 isolate

Although many coxsackie B viruses interact with decay accelerating factor (DAF), attachment to DAF by itself is not sufficient to initiate infection. We examined the early events in infection that follow virus interaction with DAF, and with the coxsackievirus and adenovirus receptor (CAR). Interaction with soluble CAR in a cell-free system, or with CAR on the surfaces of transfected cells, induced the formation of A particles; interaction with soluble or cell surface DAF did not. The results suggest that CAR, but not DAF, is capable of initiating the conformational changes in the viral capsid that lead to release of viral nucleic acid.     

Tissue specificity of the sugarcane bacilliform virus promoter in oat,barley and wheat

The tissue-specificity of the sugarcane bacilliform virus (SCBV) promoter was investigated in oat, barley, and wheat to determine whether its expression pattern in one species was predictive of promoter specificity in the other closely related Gramineae species. Progeny of transgenic plants produced using constructs containing the SCBV promoter driving gusA were sampled at different stages of plant development and stained for GUS activity using a histochemical assay. Overall, the GUS staining patterns were most similar between oat and barley. In all three species, similar GUS staining patterns were observed in mature endosperms, leaves, and floral bracts of developing infloresences. No GUS staining was detected in oat embryos whereas the entire barley embryo was stained, and GUS staining was confined to the scutellum of wheat embryos. Oat and barley stems exhibited GUS staining whereas no GUS staining was observed in stems of the transgenic wheat plants. The SCBV promoter conferred strong GUS staining intensity in most tissues of oat and barley but was generally weaker in wheat. These differences in SCBV promoter specificity indicate that promoter evaluation should be conducted in the target species of interest rather than by extrapolation from expression patterns in other species.     

Homology modeling and assigned functional annotation of an uncharacterized antitoxin protein from Streptomyces xinghaiensis

Streptomyces xinghaiensis is a Gram-positive, aerobic and non-motile bacterium. The bacterial genome is known. Therefore, it is of interest to study the uncharacterized proteins in the genome. An uncharacterized protein (gi|518540893|86 residues) in the genome was selected for a comprehensive computational sequence-structure-function analysis using available data and tools. Subcellular localization of the targeted protein with conserved residues and assigned secondary structures is documented. Sequence homology search against the protein data bank (PDB) and non-redundant GenBank proteins using BLASTp showed different homologous proteins with known antitoxin function. A homology model of the target protein was developed using a known template (PDB ID: 3CTO:A) with 62% sequence similarity in HHpred after assessment using programs PROCHECK and QMEAN6. The predicted active site using CASTp is analyzed for assigned anti-toxin function. This information finds specific utility in annotating the said uncharacterized protein in the bacterial genome.     

Detection of Helminth Eggs and Identification of Hookworm Species in Stray Cats,Dogs and Soil from Klang Valley,Malaysia

The present study was conducted to determine the prevalence of helminth eggs excreted in the faeces of stray cats, dogs and in soil samples. A total of 505 fresh samples of faeces (from 227 dogs and 152 cats) and soil were collected. The egg stage was detected via microscopy after the application of formalin–ether concentration technique. Genomic DNA was extracted from the samples containing hookworm eggs and used for further identification to the species level using real-time polymerase chain reaction coupled with high resolution melting analysis. Microscopic observation showed that the overall prevalence of helminth eggs among stray cats and dogs was 75.7% (95% CI = 71.2%–79.9%), in which 87.7% of dogs and 57.9% of cats were infected with at least one parasite genus. Five genera of heliminth eggs were detected in the faecal samples, including hookworms (46.4%), Toxocara (11.1%), Trichuris (8.4%), Spirometra (7.4%) and Ascaris (2.4%). The prevalence of helminth infections among stray dogs was significantly higher than that among stray cats (p < 0.001). Only three genera of helminths were detected in soil samples with the prevalence of 23% (95% CI = 15.1%–31%), consisting of hookworms (16.6%), Ascaris (4%) and Toxocara (2.4%). The molecular identification of hookworm species revealed that Ancylostoma ceylanicum was dominant in both faecal and soil samples. The dog hookworm, Ancylostoma caninum, was also detected among cats, which is the first such occurrence reported in Malaysia till date. This finding indicated that there was a cross-infection of A. caninum between stray cats and dogs because of their coexistent within human communities. Taken together, these data suggest the potential role of stray cats and dogs as being the main sources of environmental contamination as well as for human infections.