Hes1 regulates formations of the hypophyseal pars tuberalis and the hypothalamus

The hypophyseal pars tuberalis surrounds the median eminence and infundibular stalk of the hypothalamus as thin layers of cells. The pars tuberalis expresses MT1 melatonin receptor and participates in mediating the photoperiodic secretion of pituitary hormones. Both the rostral tip of Rathke’s pouch (pars tuberalis primordium) and the pars tuberalis expressed αGSU mRNA, and were immunoreactive for LH, chromogranin A, and TSHβ in mice. Hes genes control progenitor cell differentiation in many embryonic tissues and play a crucial role for neurulation in the central nervous system. We investigated the Hes1 function in outgrowth and differentiation of the pars tuberalis by using the markers for the pars tuberalis. In homozygous Hes1 null mutant embryos, the rostral tip was formed in the basal-ventral part of Rathke’s pouch at embryonic day (E)11.5 as well as in wild-type embryos. In contrast to the wild-type, the rostral tip of null mutants could not extend rostrally with age; it remained in the low extremity of Rathke’s pouch during E12.5–E13.5 and disappeared at E14.5, resulting in lack of the pars tuberalis. Development of the ventral diencephalon was impaired in the null mutants at early stages. Rathke’s pouch, therefore, could not link with the nervous tissue and failed to receive inductive signals from the diencephalon. In a very few mutant mice in which the ventral diencephalon was partially sustained, some pars tuberalis cells were distributed around the hypoplastic infundibulum. Thus, Hes1 is required for development of the pars tuberalis and its growth is dependent on the ventral diencephalon.     

Purification and properties of glucoside 3-dehydrogenase from Flavobacterium saccharophilum

A membrane-bound glucoside 3-dehydrogenase [EC 1.1.99.13], which oxidizes validoxylamine A to the 3-keto derivative, was solubilized from the membrane fraction of Flavobacterium saccharophilum by Triton X-100 and purified about 280-fold with an overall yield of 30% from the membrane fraction by column chromatography on DEAE- and CM-Sepharose CL-6B and gel filtration on Sephacryl S-300. The purified enzyme exhibited a single protein band on disc gel electrophoresis, and FAD was shown to be the prosthetic group. The enzyme had a molecular weight of 270,000 as determined by gel filtration on Sephacryl S-300 and consisted of 4 identical subunits each with a molecular weight of 66,000. The enzyme reacted with various artificial electron acceptors such as 2,6-dichlorophenolindophenol (DCIP), phenazine methosulfate, and ferricyanide. The optimum pH for DCIP reductase activity was 6.0. The enzyme was inhibited by Hg2+ and p-chloromercuribenzoate. D-Glucose and methyl-alpha- and beta-D-glucoside showed the highest susceptibility to the enzyme, and were converted to the corresponding 3-keto sugars.     

Identification and quantitative analysis of degradation products of chlorhexidine with chlorhexidine-resistant bacteria with three-dimensional high performance liquid chromatography

The products of the degradation of chlorhexidine by two chlorhexidine-resistant strains of Achromobacter xylosoxidans , isolated from an ultrasonic hand washer, were identified by three-dimensional HPLC. In the degradation process a pathway forming p -chlorophenol, probably through p -chloroaniline, was also observed, as was a pathway forming phenol and pyrogallol. The quantitative measurement of these products at their maximum absorption spectra by two-dimensional HPLC suggested the presence of chlorhexidine-degrading enzymes.     

Participation of superoxide, hydrogen peroxide and hydroxyl radicals in NADPH-cytochrome P-450 reductase-catalyzed peroxidation of methyl linolenate.

1. NADPH-cytochrome P-450 reductase-catalyzed peroxidation of methyl linolenate is inhibited by superoxide dismutase, catalase, ethanol, and mannitol, and is potentiated by H2O2. 2. H2O2 is shown to be generated in the incubation mixture in the presence of NADPH and NADPH-cytochrome P-450 reductase. If the system contains Fe-EDTA complex, H2O2 is not formed. In the presence of the enzyme and Fe-EDTA complex, added H2O2 is consumed. 3. In the presence of Fe-EDTA complex, NADPH-cytochrome P-450 reductase is shown to generate O-2 at a slow rate. These results suggest that H2O2 produced from O-2 is decomposed to form OH . by the action of Fe-EDTA complex in the lipid peroxidation system, and that OH . is a trigger of lipid peroxidation.     

The Chelating Ability of Adenosine-5′-Triphosphate-3′-Diphosphate (pppApp)

We have developed a new series of R4L1 Gateway binary vectors (R4L1pGWB), which carry the bialaphos resistance gene (bar) or the UDP-N-acetylglucosamine:dolichol phosphate N-acetylglucosamine-1-P transferase (GPT) gene as selection markers that confer BASTA^® and tunicamycin resistance on plants respectively. R4L1pGWBs have an attR4-attL1-reporter and can accept an attL4-promoter-attR1 entry clone for easy construction of an attB4-promoter-attB1-reporter clone. The new R4L1pGWBs facilitate promoter:reporter analysis in pre-existing transgenic plants that are resistant to kanamycin or hygromycin.     

Formation of the Recombinant between Ampicillin Re istance Determinant and Transfer Factor

In vitro-developed resistant mutants were obtained by inoculating a clinical isolate of Aerobacter cloacae on plates containing various concentrations of ampicillin (APC). This resistance was paralleled by an increase in the formation of β-lactamase. When A. cloacae carrying the nontransmissible APC resistance-determinant (amp) was infected with a T-tet factor, a recombinant T-tet.amp factor was formed; the recombinant being conjugally transmissible and capable of conferring APC resistance on their host. This fact implies the origin of the R factor; the R factor being formed by the recombination of sex factors with nontransmissible drug resistance-determinants.     

Thec-kit receptor transduces the stem cell factor-triggered growth signal in murine interleukin-3-dependent cell line

The stem cell factor is a glycoprotein hormone which regulates the proliferation and differentiation of primitive hematopoietic cells through its interaction with a tyrosine kinase transmembrane receptor which is encoded by thec-kit proto-oncogene. To examine whether a murinec-kit receptor can be functional in murine interleukin-3 (mlL-3)-dependent hematopoietic cell line, we introduced the murinec-kit cDNA into mlL-3-dependent pro-B cell line Ba/F3. One of the resulting clones, Ba/F3 clone BF-K96, expressed the 140 kDa protein recognized by anti-c-kit monoclonal antibody and the expressedc-kit receptor protein on the cell surface bound to a radiolabeled soluble form of murine stem cell factor (mSCF) with high affinity. BF-K96 clone expressing thec-kit receptor could proliferate in response to mSCF in the absence of mlL-3. The cell clone could also grow in co-culture with mouse 3T3 cells which are endogeneously expressing a membrane-associated type of mSCF on their cell surfaces. These findings demonstrate that thec-kit receptor expressed on mlL-3-dependent hematopoietic cell line Ba/F3 transduce the mSCF-dependent growth signal, indicating that established cell clone will provide a unique cellular system for the study of SCF/c-kit signal transduction mechanism.Abbreviations SCF stem cell factor - IL interleukin - CSF colony stimulating factor - IMDM Iscove's Modified Dulbecco's Medium - DME Dulbecco's Modified Eagle's Medium - FCS fetal calf serum - PCR polymerase chain reaction - EDTA ethylenediaminetetra-acetic acid; sodium dodecyl sulfate