Biological effects of Spirometra erinacei plerocercoids in several species of rodents

Observations were made of the biological effects on infection with plerocercoids of Spirometra erinacei on normal female Snell mice, male chinese hamsters, golden hamsters, normal and hypox rats. Plerocercoid infection caused the strongest growth-promoting effect on normal Snell mice. In mice, this effect appears to be independent of strain. Chinese hamsters infected with these larvae showed similar growth. The infected normal rats and golden hamsters, however, showed a weight increase in the skeletal muscle only, while the hypox rats exhibited no effect at all. The elevation in the concentration of serum triglyceride was observed in all the animals investigated except for rats. Golden hamsters, in particular, exhibited a marked increase in the concentration of serum free fatty acids and total cholesterol. There was close correlation between the concentrations of serum triglyceride and free fatty acids, and the regression coefficient of the resulting linear regression equation for the experimentals was higher than that for the controls. This suggests that serum triglyceride results from an increased concentration of serum free fatty acids derived from stimulated lipolysis. The total cholesterol concentration in the serum decreased in chinese hamsters infected with larvae. The serum glucose concentration increased in normal Snell mice but decreased in chinese and golden hamsters. No difference in glycerol and free fatty acid concentration was observed in infected animals except for golden hamsters.     

Changes in element concentration and distribution in breast-milk fractions of a healthy lactating mother

Daily changes in components of breast milk with number of days of lactation after delivery were demonstrated by determining concentrations and distributions of several elements simultaneously. Concentrations of calcium, copper, magnesium, phosphorus, sulfur, and zinc were determined simultaneously by inductively coupled argon plasma-atomic-emission spectrometry (ICP) for whole milk and milk fractions (skimmed milk and whey) collected from 2 to 196 d postpartum from a healthy lactating mother. Calcium and phosphorus concentrations increased in transitional milk. With days postpartum, the other elements decreased from the highest concentrations in colostrum milk, the modes of decrease being characteristic for each element. Distributions of copper, iron, phosphorus, sulfur, and zinc in whey were determined on a gel-filtration column by HPLC with ICP detection (HPLC-ICP method). Distributions of the five elements and absorbance peaks at 254 and 280 nm changed dramatically day by day at the beginning (colostrum milk), resulting in constant distributions after 30 d (mature milk). These results suggest the important roles of daily changing constituents in breast milk, especially in colostrum milk, in the nutrition of the newborn. Several element peaks on a gelfiltration column were identified by comparison with standard samples.     

A newly isolated heterotrophic bacterium,Xanthomonas sp. DY44, to oxidize hydrogen sulfide to polysulfide

Summary A newly isolated heterotrophic bacterium,Xanthomonas sp. DY44, was found to be capable of oxidizing hydrogen sulfide (H₂S). Cells made non-viable by heat treatment (120°C, 20 min) did not show H₂S oxidation. However, both cells sterilized by -rays irradiation and cell-free extract oxidized H₂S, suggesting the existence of the heat-labile intracellular enzymatic system for H₂S oxidation. AsXanthomonas sp. DY44 exhibited no autotrophic growth with H₂S in basal mineral medium, the H₂S oxidation was judged not to be a consequence of chemolithotrophic activity. Using X-rays photoelectron spectroscopy (XPS), the metabolic product of H₂S oxidation was assessed to be polysulfide.     

Restricted degradation of U6 RNA in a nuclear extract of Ehrlich ascites tumor cells

A new nucleolytic activity that causes restricted digestion of U6 RNA was found in a nuclear extract of Ehrlich ascites tumor cells. This nucleolytic activity specifically degrades U6 RNA in the vicinity of its 3'-end with accumulation of a discrete sized degradation product of RNA of 90-95 nucleotides. Since this degradation product was not digested further by the nuclease under these conditions, this trimming of U6 RNA is supposed to be a biologically meaningful reaction. This nucleolytic activity required Mg2+, and was inhibited by Zn2+ or Ca2+.     

Metamorphosis-associated and region-specific expression of calbindin gene in the posterior intestinal epithelium of Xenopus laevis larva

The present study used a molecular approach toward understanding the mechanism of hormone- and region-dependent remodeling of the small intestine during metamorphosis of Xenopus laevis . A protein spot was noticed on a two-dimensional polyacrylamide gel as a protein whose expression was metamorphic stage- and region-dependent. The protein was identified as the Xenopus homolog (Xcalbindin) of chick calbindin D_28k. Xcalbindin expression in the intestine was restricted to absorptive cells in the posterior part, being detectable at stages 49–61, not detectable at stages 62–63, detectable again at stages 64–66, and finally becoming undetectable in the adult. During spontaneous metamorphosis, the level of Xcalbindin mRNA was significantly increased between stages 57 and 58, dramatically reduced at stage 59, and the mRNA was undetectable from stages 60–63, after which it was weakly re-expressed until the end of metamorphosis. Such up- and down-regulation of Xcalbindin mRNA was induced precociously by exogenous thyroid hormone. These results indicated that Xcalbindin is a specific marker of the differentiated absorptive cells of the intestine. Immunohistochemistry with specific antibodies against Xcalbindin demonstrated that precursor cells of adult intestinal epithelial cells expressed Xcalbindin. Considering these results, the origin of adult intestinal epithelial cells was discussed.     

Degradation of hydrogen sulfide by Xanthomonas sp. strain DY44 isolated from peat.

Xanthomonas sp. strain DY44, capable of degrading H2S, was isolated from dimethyl disulfide-acclimated peat. This bacterium removed H2S either as a single gas or in the presence of the sulfur-containing compounds methanethiol, dimethyl sulfide, and dimethyl disulfide. The maximum specific H2S removal rate, obtained in the late stationary phase, was 3.92 mmol g of dry cells-1 h-1 (6.7 x 10(-16) mol cell-1 h-1) at pH 7 and 30 degrees C through a batch experiment in a basal mineral medium. Since Xanthomonas sp. strain DY44 exhibited no autotrophic growth with H2S, the H2S removal was judged not to be a consequence of chemolithotrophic activity. By using X-ray photoelectron spectroscopy, the metabolic product of H2S oxidation was determined to be polysulfide, which has properties very similar to those of elemental sulfur. Autoclaved cells (120 degrees C, 20 min) did not show H2S degradation, but cells killed by gamma-irradiation and cell extracts both oxidized H2S, suggesting the existence of a heat-labile intracellular enzymatic system for H2S oxidation. When Xanthomonas sp. strain DY44 was inoculated into fibrous peat, this strain degraded H2S without lag time, suggesting that it will be a good candidate for maintaining high H2S removability in the treatment of exhaust gases.     

Human P-glycoprotein transports cortisol, aldosterone, and dexamethasone, but not progesterone.

We expressed human MDR1 cDNA isolated from the human adrenal gland in porcine LLC-PK1 cells. A highly polarized epithelium formed by LLC-GA5-COL300 cells that expressed human P-glycoprotein specifically on the apical surface showed a multidrug-resistant phenotype and had 8.3-, 3.4-, and 6.5-fold higher net basal to apical transport of 3H-labeled cortisol, aldosterone, and dexamethasone, respectively, compared with host cells. But progesterone was not transported, although it inhibited azidopine photoaffinity labeling of human P-glycoprotein and increased the sensitivity of multidrug-resistant cells to vinblastine. An excess of progesterone inhibited the transepithelial transport of cortisol by P-glycoprotein. These results suggest that cortisol and aldosterone are physiological substrates for P-glycoprotein in the human adrenal cortex and that substances that efficiently bind to P-glycoprotein are not necessarily transported by P-glycoprotein.     

CHLPEP—A database of chloroplast transit peptides

Transit peptides are N-terminal extensions that serve to route nuclearencoded proteins into chloroplasts. We have collected amino acid sequences for approximately 260 transit peptides, and have constructed a database that presently runs under FileMaker Plus on Macintosh personal computers. In addition, the collection is available as an ASCII-file, either in a tab-delimited format suitable for import into other database programs, or in a format with line-identifiers similar to the widely used Swiss Prot database. We hope that the plant molecular biology community will help us ensure that the collection is kept up to date by submitting new sequences directly to us.