Extracellular matrix development during differentiation into adipocytes with a unique increase in type V and VI collagen

In order to study how adipose conversion affects the extracellular environment, levels of extracellular matrix (ECM) proteins during differentiation were analyzed by 125I-labeled antibody binding to each specific primary antibody. When confluent bovine intramuscular preadipocytes (BIP) were stimulated with adipogenic medium, there was a significant accretion on the cell surface of type I-VI collagens, laminin and fibronectin, compared with undifferentiated cells. The deposition amount of ECM proteins had reached near maximal levels at an early stage of differentiation and lasted throughout the culture. However, the increasing manners were not all the same in these eight proteins. Type V and type VI collagen tended to show a transient decline after the rapid rise at the beginning of stimulation, and fibronectin instead, subsequently decreased. Further analysis by immunocytochemical staining showed that remodeling occurred in type V and VI collagen matrices during this period; extensive fibrillar networks seen at 10 d after stimulation were quite unlike that formed earlier. These specific increases and development of matrix during adipocyte differentiation imply some significance for organizing fat lobules in each ECM proteins, especially type V and VI collagens.     

Effects of canonical Wnt signaling on dorso-ventral specification of the mouse telencephalon

Wnt signaling is involved in numerous processes during vertebrate CNS development. In this study, we used conditional Cre/loxP system in mouse to ablate or activate beta-catenin in the telencephalon in two time windows: before and after the onset of neurogenesis. We show that beta-catenin mediated Wnt signals are required to maintain the molecular identity of the pallium. Inactivation of beta-catenin in the telencephalon before neurogenesis results in downregulated expression of dorsal markers Emx1, Emx2 and Ngn2, and in ectopic up-regulation of ventral markers Gsh2, Mash1 and Dlx2 in the pallium. In contrast, ablation of ss-catenin after the onset of cortical neurogenesis (E11.5) does not result in a dorso-ventral fate shift. In addition, activation of canonical Wnt signaling in the subpallium leads to a repression of ventral telencephalic cell identities as shown by the down-regulation of subpallial markers Dlx2, Nkx2.1, Gsh2, Olig2 and Mash1. This was accompanied with an expansion of dorsal identities ventrally as shown by the expanded expression domains of pallial markers Pax6 and Ngn2. Thus, our data suggest that canonical Wnt signals are involved in maintaining the identity of the pallium by controlling expression of dorsal markers and by suppressing ventral programs from being activated in pallial progenitor cells.     

Intraepithelial gammadelta T cells may bridge a gap between innate immunity and acquired immunity to herpes simplex virus type 2

Mice depleted of gammadelta T cells by in vivo administration of anti-TCRgammadelta monoclonal antibodies showed susceptibility against an intravaginal infection with herpes simplex virus type 2 (HSV-2). The systemic Th1 response was impaired in the gammadelta T-cell-depleted mice. Mice deficient in the Vdelta1 T subset were susceptible to an intravaginal infection with HSV-2. Intraepithelial gammadelta T cells bearing Vdelta1 may help protect against intravaginal infection with HSV-2 through promoting the systemic Th1 response.     

Acetobacter aceti possesses a proton motive force-dependent efflux system for acetic acid

Acetic acid bacteria are obligate aerobes able to oxidize ethanol, sugar alcohols, and sugars into their corresponding acids. Among them, Acetobacter and Gluconacetobacter species have very high ethanol oxidation capacity, leading to accumulation of vast amounts of acetic acid outside the cell. Since these bacteria are able to grow in media with high concentrations of acetic acid, they must possess a specific mechanism such as an efflux pump by which they can resist the toxic effects of acetic acid. In this study, the efflux pump of Acetobacter aceti IFO 3283 was examined using intact cells and membrane vesicles. The accumulation of acetic acid/acetate in intact cells was increased by the addition of a proton uncoupler and/or cyanide, suggesting the presence of an energy-dependent efflux system. To confirm this, right-side-out and inside-out membrane vesicles were prepared from A. aceti IFO 3283, and the accumulation of acetic acid/acetate in the vesicles was examined. Upon the addition of a respiratory substrate, the accumulation of acetic acid/acetate in the right-side-out vesicles was largely decreased, while its accumulation was very much increased in the inside-out vesicles. These respiration-dependent phenomena observed in both types of membrane vesicles were all sensitive to a proton uncoupler. Acetic acid/acetate uptake in the inside-out membrane vesicles was dependent not on ATP but on the proton motive force. Furthermore, uptake was shown to be rather specific for acetic acid and to be pH dependent, because higher uptake was observed at lower pH. Thus, A. aceti IFO 3283 possesses a proton motive force-dependent efflux pump for acetic acid.     

Morphological development of the mouse gonad in tda-1 XY sex reversal

tda-1 XY sex reversal occurs when the Y chromosome of at least some populations of wild Mus musculus domesticus is placed on the C57BL/6J genomic background. Gross anatomical observations have previously revealed morphological similarities among fetal ovotestes of tda-1 and Tas-inherited XY sex reversals and BALB/cWt mosaic hermaphrodites. We studied the histology of tda-1 XY sex-reversed gonads, ranging in age from day 14 of gestation to adult. The obtained data revealed additional similarities with ovotestes of BALB/cWt mosaic hermaphrodites as well as with ovotestes of hermaphrodites found in XXSxr and XX/XY chimeras. It is proposed that ovotestes occurring in these various hermaphroditic conditions may be formed through a common pathway.     

DNA transfection of Escherichia coli by electroporation

Electroporation was applied to transfection and transformation of Escherichia coli. Efficient transfer of DNA was achieved by a single voltage pulse at 2.5 kV (initial electric field strength = 6.25 kV/cm), with a 25 microF capacitor. As the recipient for transfecting DNA in the electroporation, spheroplasts, EDTA-treated cells and osmotically shocked bacteria were inferior to intact E. coli. Various parameters affecting the transfection efficiency were defined including growth phase of recipient cells, concentrations of DNA and cells, temperature and additions. In most strains tested, electroporation was far more efficient than Ca2+-dependent transfection (transformation). Various aspects of the electroporation-mediated DNA uptake are discussed.