Fermentation Studies with Streptomyces griseus: I. Carbohydrate Sources for the Production of Protease and Streptomycin

The effects of four carbon sources and inorganic phosphate on the production of streptomycin and protease by a strain of Streptomyces griseus were studied. Protease production was increased in fermentations with comparatively rapid consumption of carbohydrate, and streptomycin was produced under conditions of moderately slow consumption. Starch was consumed more rapidly than glucose, and, in fermentations with starch as a carbon source, good yields of protease were associated with poor yields of streptomycin. The effect of the concentration of inorganic phosphate varied with the sugar source; the rate of consumption of glucose or fructose increased with the addition of inorganic phosphate, and the utilization of starch or maltose was not affected.     

Cell cycle regulation of human CDC6 protein. Intracellular localization, interaction with the human mcm complex, and CDC2 kinase-mediated hyperphosphorylation.

The binding of mammalian MCM complexes to chromatin is cell cycle-regulated and under CDC2 kinase negative control. Here, we investigated the properties of mammalian CDC6 protein, a candidate regulator of MCM. The levels of CDC6 were relatively constant during the HeLa cell cycle. In asynchronous cells, CDC6 was mainly detected in the nuclei with immunostaining, but some CDC6 was not extractable with nonionic detergent. In contrast to the chromatin-bound MCM, this fraction of CDC6 was resistant to DNase I treatment, suggesting that it binds to the detergent- and nuclease-resistant nuclear structure. In S phase cells, CDC6 became detectable in the cytoplasm with immunostaining; however, the level of the bound CDC6 was unchanged. In G(2)/M phase cells, the level of the bound CDC6 was still maintained, which was hyperphosphorylated by CDC2 kinase. These data suggest that some CDC6 protein is associated with the specific nuclear structure throughout the cell cycle and that major binding sites on chromatin differ between MCM and CDC6. However, co-immunoprecipitation assays with chemical cross-linking indicated that a small part of the chromatin-bound MCM is present close to the bound CDC6.     

Platelet prostaglandin E1 hyposensitivity in schizophrenia: reduction of prostaglandin E1- or forskolin-stimulated cyclic AMP response in platelets

Cyclic 3',5'-adenosine monophosphate (cAMP) formation via prostaglandin E1 (PGE1)-or forskolin-stimulation were determined in washed intact platelets from 32 schizophrenic patients and 30 normal controls. Regarding basal cAMP levels in the platelets, there were no differences between schizophrenic patients and normal controls. Both PGE1-and forskolin-stimulated cAMP response reduced in platelets from schizophrenics compared with normal controls. These results suggested that platelets in schizophrenics were impaired not only in the adenylate cyclase unit per se but also extensively in the cAMP generating system coupled to a PGE1 receptor.     

Features of a newly cloned pig C1 esterase inhibitor

The pig cDNA encoding C1 esterase inhibitor (C1-INH) was isolated and the homology of the sequence was compared with that from other animals. The structure of pig C1-INH contains a two disulfide bridge pattern identical to the human C1-INH. In the amino acid sequence of the first Cys-91 to the C-terminal end, the pigC1-INH has a 76.2% homology with the human protein, and the sequence of the reactive site is close to the human. A surface-bound form of pig and human C1-INH, pC1-INH-PI and hC1-INH, respectively, were next constructed. Stable Chinese hamster ovarian tumor (CHO) cell lines and pig endothelial cell (PEC) lines expressing these C1-INH-PI were prepared by transfection. The basic function and the species specificity of pCI-INH were then investigated using these transfectants. pC1-INH and hC1-INH have almost the same suppressive effect on pig, human, dog and rabbit sera in complement-dependent cell lysis, indicating little species specificity.     

(−)-Epigallocatechin gallate inhibits growth and activation of the VEGF/VEGFR axis in human colorectal cancer cells

(?)-Epigallocatechin gallate (EGCG), the major constituent of green tea, inhibits the growth of colorectal cancer cells by inhibiting the activation of various types of receptor tyrosine kinases (RTKs). The RTK vascular endothelial growth factor (VEGF)/VEGF receptor (VEGFR) axis induces tumor angiogenesis in colorectal cancer. This study examined the effects of EGCG on the activity of the VEGF/VEGFR axis and the expression of hypoxia-inducible factor (HIF)-1α, which promotes angiogenesis by elevating VEGF levels, in human colorectal cancer cells. Total and phosphorylated (i.e., activated) form (p-VEGFR-2) of VEGFR-2 proteins were overexpressed in a series of human colorectal cancer cell lines. Within 3 h, EGCG caused a decrease in the expression of HIF-1α protein and VEGF, HIF-1α, insulin-like growth factor (IGF)-1, IGF-2, epidermal growth factor (EGF), and heregulin mRNAs in SW837 colorectal cancer cells, which express a constitutively activated VEGF/VEGFR axis. A decrease was also observed in the expression of VEGFR-2, p-VEGFR-2, p-IGF-1 receptor, p-ERK, and p-Akt proteins within 6 h after EGCG treatment. Drinking EGCG significantly inhibited the growth of SW837 xenografts in nude mice, and this was associated with the inhibition of the expression and activation of VEGFR-2. The consumption of EGCG also inhibited activation of ERK and Akt, both of which are downstream signaling molecules of the VEGF/VEGFR axis, and reduced the expression of VEGF mRNA in xenografts. These findings suggest that EGCG may exert, at least in part, growth-inhibitory effects on colorectal cancer cells by inhibiting the activation of the VEGF/VEGFR axis through suppressing the expression of HIF-1α and several major growth factors. EGCG may therefore be useful in the chemoprevention and/or treatment of colorectal cancer.     

Significance of light-induced hook exaggeration as reinforced by the concomitant anatomical change of germinating tomato seeds

Progression of the apical hook of tomato, Solanum lycopersicum, exaggerated by phytochrome mediation at the early germination stage, is followed in detail macroscopically and anatomically, and its proposed significance, i.e., survival by securing the seed coat release in the field, is reinforced by new findings. Furthermore, after self-release or artificial removal of the seed coat and the endosperm, no hook exaggeration occurs any more. Similar light-induced hook exaggeration (LIHE) is also found in carrot, parsley and Cryptotaenia japonica, which share some seed characteristics with tomato. These findings also support the above-stated significance.Key words: apical hook, carrot, cotyledons, Cryptotaenia japonica, endosperm, field germination, light action, parsley, phytochrome, seed coat, Solanum lycopersicumContrary to many other seed species,^1–3 the apical hook of germinating tomato seeds is exaggerated by red (R) and far-red light (FR) given in a pulse or continuously, mediated by the very low and low fluence responses of phytochromes.⁴ Also, an R high-irradiance response is probably involved.⁴ Based on some simulation experiments for germination in the field, we have proposed that LIHE may play a role, not in breaking through compacted soil surface, but in securing to release the seed coat at some depth of soil in response to light coming through soil gaps.⁴ Here we present additional observations and experimental data not published yet and reinforce the proposed significance of the recently discovered photo-response.     

The Staurotypus Turtles and Aves Share the Same Origin of Sex Chromosomes but Evolved Different Types of Heterogametic Sex Determination

Reptiles have a wide diversity of sex-determining mechanisms and types of sex chromosomes. Turtles exhibit temperature-dependent sex determination and genotypic sex determination, with male heterogametic (XX/XY) and female heterogametic (ZZ/ZW) sex chromosomes. Identification of sex chromosomes in many turtle species and their comparative genomic analysis are of great significance to understand the evolutionary processes of sex determination and sex chromosome differentiation in Testudines. The Mexican giant musk turtle (Staurotypus triporcatus, Kinosternidae, Testudines) and the giant musk turtle (Staurotypus salvinii) have heteromorphic XY sex chromosomes with a low degree of morphological differentiation; however, their origin and linkage group are still unknown. Cross-species chromosome painting with chromosome-specific DNA from Chinese soft-shelled turtle (Pelodiscus sinensis) revealed that the X and Y chromosomes of S. triporcatus have homology with P. sinensis chromosome 6, which corresponds to the chicken Z chromosome. We cloned cDNA fragments of S. triporcatus homologs of 16 chicken Z-linked genes and mapped them to S. triporcatus and S. salvinii chromosomes using fluorescence in situ hybridization. Sixteen genes were localized to the X and Y long arms in the same order in both species. The orders were also almost the same as those of the ostrich (Struthio camelus) Z chromosome, which retains the primitive state of the avian ancestral Z chromosome. These results strongly suggest that the X and Y chromosomes of Staurotypus turtles are at a very early stage of sex chromosome differentiation, and that these chromosomes and the avian ZW chromosomes share the same origin. Nonetheless, the turtles and birds acquired different systems of heterogametic sex determination during their evolution.     

Chromosaponin I stimulates the growth of lettuce roots

A γ-pyronyl triterpenoid saponin termed chromosaponin 1 (CSI), a conjugate of soyasaponin I and γ-pyrone, was found at 3 mM to stimulate the growth of lettuce root ( Lactuca sativa L. ev. Grand Rapids) to about 190% of the control. Since CSI is an amphipathic reductant, the stimulating effect of this saponin was compared with other reductants and other surface-active compounds. Trolox (2-carboxy-2.5.7.8-tetraamethyl-6-chromanol). another amphipathic reductant, also stimulated root growth, while other hydrophilic reductants including ascorbate. NADPH, NADH and glutathione did not. Some surfactants promoted root growth but their stimulating effects were smaller than the optimum effect of CSI. These results suggest a possible Function of CSI as an amphipathic reductant in root growth regulation.