MRI detection of thrombin with aptamer functionalized superparamagnetic iron oxide nanoparticles

Design of smart MRI contrast agent based on superparamagnetic iron oxide nanoparticles and aptamers has been described for the detection of human alpha-thrombin protein. The contrast agent is based on the assembly of the aptamer functionalized nanoparticles in the presence of thrombin. A detectable change in MRI signal is observed with 25 nM thrombin in human serum. Changes were neither observed with control analytes, streptavidin, or bovine serum albumin, nor with inactive aptamer functionalized nanoparticles.     

Overexpression of the Tn5 transposase in Escherichia coli results in filamentation, aberrant nucleoid segregation, and cell death: analysis of E. coli and transposase suppressor mutations.

Overexpression of the Tn5 transposase (Tnp) was found to be lethal to Escherichia coli. This killing was not caused by transposition or dependent on the transpositional or DNA binding competence of Tnp. Instead, it was strictly correlated with the presence of a wild-type N terminus. Deletions removing just two N-terminal amino acids of Tnp resulted in partial suppression of this effect, and deletions of Tnp removing 3 or 11 N-terminal amino acids abolished the killing effect. This cytotoxic effect of Tnp overexpression is accompanied by extensive filament formation (i.e., a defect in cell division) and aberrant nucleoid segregation. Four E. coli mutants were isolated which allow survival upon Tnp overexpression, and the mutations are located at four discrete loci. These suppressor mutations map near essential genes involved in cell division and DNA segregation. One of these mutations maps to a 4.5-kb HindIII region containing the ftsYEX (cell division) locus at 76 min. A simple proposition which accounts for all of these observations is that Tnp interacts with an essential E. coli factor affecting cell division and/or chromosome segregation and that overexpression of Tnp titrates this factor below a level required for viability of the cell. Furthermore, the N terminus of Tnp is necessary for this interaction. The possible significance of this phenomenon for the transposition process is discussed.     

Molecular phylogeny of the Cricetinae subfamily based on the mitochondrial cytochrome b and 12S rRNA genes and the nuclear vWF gene

Despite some popularity of hamsters as pets and laboratory animals there is no reliable phylogeny of the subfamily Cricetinae available so far. Contradicting views exist not only about the actual number of species but also concerning the validity of several genera. We used partial DNA sequences of two mitochondrial (cytochrome b, 12S rRNA) and one partial nuclear gene (von Willebrand Factor exon 28) to provide a first gene tree of the Cricetinae based on 15 taxa comprising six genera. According to our data, Palaearctic hamsters fall into three distinct phylogenetic groups: Phodopus, Mesocricetus, and Cricetus-related species which evolved during the late Miocene about 7-12MY ago. Surprisingly, the genus Phodopus, which was previously thought to have appeared during the Pleistocene, forms the oldest clade. The largest number of extant hamster genera is found in a group of Cricetus-related hamsters. The genus Cricetulus itself proved to be not truly monophyletic with Cricetulus migratorius appearing more closely related to Tscherskia, Cricetus, and Allocricetulus. We propose to place the species within a new monotypic genus. Molecular clock calculations are not always in line with the dating of fossil records. DNA based divergence time estimates as well as taxonomic relationships demand a reevaluation of morphological characters previously used to identify fossils and extant hamsters.     

Migration of Myeloid Cells during Inflammation Is Differentially Regulated by the Cell Surface Receptors Slamf1 and Slamf8

Previous studies have demonstrated that the cell surface receptor Slamf1 (CD150) is requisite for optimal NADPH-oxidase (Nox2) dependent reactive oxygen species (ROS) production by phagocytes in response to Gram- bacteria. By contrast, Slamf8 (CD353) is a negative regulator of ROS in response to Gram+ and Gram- bacteria. Employing in vivo migration after skin sensitization, induction of peritonitis, and repopulation of the small intestine demonstrates that in vivo migration of Slamf1^-/- dendritic cells and macrophages is reduced, as compared to wt mice. By contrast, in vivo migration of Slamf8^-/- dendritic cells, macrophages and neutrophils is accelerated. These opposing effects of Slamf1 and Slamf8 are cell-intrinsic as judged by in vitro migration in transwell chambers in response to CCL19, CCL21 or CSF-1. Importantly, inhibiting ROS production of Slamf8^-/- macrophages by diphenyleneiodonium chloride blocks this in vitro migration. We conclude that Slamf1 and Slamf8 govern ROS–dependent innate immune responses of myeloid cells, thus modulating migration of these cells during inflammation in an opposing manner.     

Histological changes in the uterus of the hens after embryonic exposure to bisphenol A and diethylstilbestrol

Many employed chemicals in industries have estrogenic hormone effects on organisms, and these are called as environmental estrogens. Environmental estrogens have adverse effects on development and function of reproductive organs of the birds. Bisphenol A (BPA) is one of the best known environmental estrogens widely found in plastic products. In this study, we injected BPA and the synthetic estrogen diethylstilbestrol (DES) in ovo and then examined and compared the effects of those on the uteri (shell gland) of the adult hens by histological methods. Five groups have been designed in the current study. Only vehicle substance was given in ovo to the control group and BPA (67 or 134 μg/g egg) and DES (0.02 or 0.2 μg/g egg) were administered in the experimental groups. Tissue specimens were taken from uteri of hens at 21 weeks of age, prior to the laying period. Estrogen receptor alpha (ERα) was immunohistochemically stained. It was observed that the hatching proportion in BPA (67 μg and 134 μg/g) was lesser than the other groups (P?<?0.01). Uterine tubular glandular density and thickness of tunica mucosa were found to have reduced (P?<?0.01) in BPA (134 μg/g) and DES (0.2 μg/g) groups, in comparison with those of the control and the other experimental groups. Uterine gland epithelium revealed positive immunoreaction for ERα. These findings suggested that administration of BPA and DES at high doses affected embryonic development in a negative way, and this adverse effect was seen less in adult period.     

Ghrelin and adipokines as circulating markers of disease activity in patients with Takayasu arteritis

Introduction

The current markers of disease activity in Takayasu arteritis (TA) are insufficient for proper assessment. We investigated circulating levels of unacylated and acylated ghrelin, leptin and adiponectin and their relationships with disease activity in patients with TA.

Methods

This study included 31 patients with TA and 32 sex-, age- and body mass index-matched healthy controls. Disease activity was assessed in TA patients using various tools, including Kerr''s criteria, disease extent index-Takayasu, physician''s global assessment, radiological parameters, and laboratory markers. Plasma unacylated and acylated ghrelin, and serum leptin and adiponectin levels were measured using an enzyme-linked immunosorbent assay.

Results

Unacylated and acylated ghrelin levels were found to be significantly lower in TA patients than that in healthy controls. Patients with active disease had lower unacylated ghrelin levels than those with inactive disease and had lower acylated ghrelin levels than healthy controls. Ghrelin levels were negatively correlated with various parameters of disease activity. The leptin/ghrelin ratio was significantly higher in TA patients than controls. It was positively correlated with disease activity. There was a positive correlation between unacylated and acylated ghrelin and a negative correlation between leptin and ghrelin. There was no statistical difference in adiponectin levels between TA patients and controls. The radiological activity markers were positively correlated with other parameters of disease activity.

Conclusions

This study suggests that plasma unacylated and acylated ghrelin levels may be useful in monitoring disease activity and planning treatment strategies for patients with TA. The serum leptin level and leptin/ghrelin ratio may also be used to help assess the disease activity.     

Temtamy preaxial brachydactyly syndrome is caused by loss-of-function mutations in chondroitin synthase 1, a potential target of BMP signaling

Altered Bone Morphogenetic Protein (BMP) signaling leads to multiple developmental defects, including brachydactyly and deafness. Here we identify chondroitin synthase 1 (CHSY1) as a potential mediator of BMP effects. We show that loss of human CHSY1 function causes autosomal-recessive Temtamy preaxial brachydactyly syndrome (TPBS), mainly characterized by limb malformations, short stature, and hearing loss. After mapping the TPBS locus to chromosome 15q26-qterm, we identified causative mutations in five consanguineous TPBS families. In zebrafish, antisense-mediated chsy1 knockdown causes defects in multiple developmental processes, some of which are likely to also be causative in the etiology of TPBS. In the inner ears of zebrafish larvae, chsy1 is expressed similarly to the BMP inhibitor dan and in a complementary fashion to bmp2b. Furthermore, unrestricted Bmp2b signaling or loss of Dan activity leads to reduced chsy1 expression and, during epithelial morphogenesis, defects similar to those that occur upon Chsy1 inactivation, indicating that Bmp signaling affects inner-ear development by repressing chsy1. In addition, we obtained strikingly similar zebrafish phenotypes after chsy1 overexpression, which might explain why, in humans, brachydactyly can be caused by mutations leading either to loss or to gain of BMP signaling.     

Golden hamsters are nocturnal in captivity but diurnal in nature

Daily activity rhythms are nearly universal among animals and their specific pattern is an adaptation of each species to its ecological niche. Owing to the extremely consistent nocturnal patterns of activity shown by golden hamsters (Mesocricetus auratus) in the laboratory, this species is a prime model for studying the mechanisms controlling circadian rhythms. In contrast to laboratory data, we discovered that female hamsters in the wild were almost exclusively diurnal. These results raise many questions about the ecological variables that shape the activity patterns in golden hamsters and the differences between laboratory and field results.