Action of 5-(2-thienyl) valeric acid as a biotin antagonist

5-(2-Thienyl)valeric acid (TVA), a biotin analogue which can be easily prepared through chemical process, inhibited the growth of a biotin synthesizing Rhodotorula glutinis. The growth inhibition was reversed by the addition of biotin. Among biotin intermediates, dethiobiotin and 7,8-diaminopelargonic acid reversed the inhibition by TVA, while 7-keto-8-amino-pelargonic acid and pimelic acid did not. From these results, it was concluded that TVA is a biotin antagonist which probably acts as an inhibitor of biotin biosynthesis.     

Determination of Pseudomonas aeruginosa by Biochemical Test Methods

A new test method was devised for microbial gluconate oxidation, using an ammonium molybdate reagent. One loopful (about 2 mg wet wt.) of the test organism, grown on a nutrient agar plate for 18 hr, is transferred into 1 ml of the test liquid medium consisting of (NH₄)₂SO₄ 0.5 mg, potassium gluconate 10 mg, NaCl 5 mg, KH₂PO₄ 2 mg, MgSO₄·7H₂O 0.1 mg, and 1 ml of distilled water, incubated at 37 C for 6 hr without shaking, and then mixed with 3 ml of 1% aqueous solution of ammonium molybdate and 0.2 ml of glacial acetic acid. The mixture is heated in boiling water for 5 min, followed by abrupt cooling with running water. A deep blue colour appears in a positive result. A total of 39 strains of Pseudomonas aeruginosa showed positive results by this method, whereas Aeromonas, Vibrio, Proteus group, Klebsiella, Citrobacter and Enterobacter A group were all negative. Though some strains of Enterobacter B group showed a weak blue colour, it could be easily differentiated from the deep blue colour of Pseudomonas. Longer incubation of test microbes in the test medium, and longer heating of the reaction mixture gave unsatisfactory results.     

Suppression of in vivo tumor growth by the transfection of the interleukin-5 gene into colon tumor cells

To investigate the influence of tumor producing interleukin-5 (IL-5) on growth kinetics of tumors, we transduced the murine IL-5 gene into murine colon C26 tumor cells. Two IL-5-secreting clones, low-level IL-5 producer C26-8B and high-level IL-5 producer C26-6F, were established. Both tumors, C26-6F and C26-8B, grew more slowly than the mock C26 tumor, although the in vitro growth rate of these IL-5 transfectants was much the same as that of the mock C26 cells. There was a significantly decreased number of colonies in the lung of mice given C26-6F or C26-8B tumors i.v. than in mice given mock C26 tumors i.v. Moreover, in mice given C26-6F cells i.v., a smaller number of tumor colonies in the lung was observed, as compared to the case with C26-6B cells. While the growth rate of C26-8B tumors in mice treated with anti-IL-5 mAb was more rapid than that seen in control mAb-treated mice, growth of C26-6F tumors in anti-IL-5-mAb-treated mice was slightly more rapid compared to findings in control mAb-treated mice. The isotypematched mAb did not alter the in vitro growth of mock-C26 cells or of the IL-5-gene-modified C26 cells. Growth of IL-5-secreting C26 tumors transplanted in nude mice was also inhibited. These results suggest that tumor-producing IL-5 inhibits growth of colon tumors mediated through T-cell-independent protective mechanisms of the host.     

The effect of the cytoplasmic tail of influenza C virus CM2 protein on its biochemical properties and intracellular processing

CM2 is an integral membrane protein encoded by the influenza C virus M gene. To examine the effects of the cytoplasmic tail of CM2 on its biochemical properties, deletion and substitution mutations were introduced into CM2 cytoplasmic tail at residues 47–115, and the expressed CM2 mutants were investigated. Although the cytoplasmic tail is not essential for the oligomerization of CM2, it may affect the degree of oligomerization. The residues 47–48, 67–69, 73–90 and 113–115 were all required for the proper expression of CM2. Pulse-chase experiments suggest that residues 47–48, 67–69, 73–75 and 79–87 stabilize CM2, thereby affecting CM2 expression. The C-terminal region at residues 61–115 is not essential for CM2 transport to the cell surface, and a 14-amino-acid, but not an 11-amino-acid, cytoplasmic tail is sufficient for the cell surface expression of CM2. These results suggest that either certain amino acid sequences or the length of the CM2 cytoplasmic tail are necessary for the proper conformational maturation, stability, expression level and intracellular transport of CM2.     

Mixed Mating System Are Regulated by Fecundity in Shorea curtisii (Dipterocarpaceae) as Revealed by Comparison under Different Pollen Limited Conditions

The maintenance of mixed mating was studied in Shorea curtisii, a dominant and widely distributed dipterocarp species in Southeast Asia. Paternity and hierarchical Bayesian analyses were used to estimate the parameters of pollen dispersal kernel, male fecundity and self-pollen affinity. We hypothesized that partial self incompatibility and/or inbreeding depression reduce the number of selfed seeds if the mother trees receive sufficient pollen, whereas reproductive assurance increases the numbers of selfed seeds under low amounts of pollen. Comparison of estimated parameters of self-pollen affinity between high density undisturbed and low density selectively logged forests indicated that self-pollen was selectively excluded from mating in the former, probably due to partial self incompatibility or inbreeding depression until seed maturation. By estimating the self-pollen affinity of each mother tree in both forests, mother trees with higher amount of self-pollen indicated significance of self-pollen affinity with negative estimated value. The exclusion of self-fertilization and/or inbreeding depression during seed maturation occurred in the mother trees with large female fecundity, whereas reproductive assurance increased self-fertilization in the mother trees with lower female fecundity.     

Apnea during Cheyne-Stokes-like breathing detected by a piezoelectric sensor for screening of sleep disordered breathing

Sleep and Biological Rhythms - A simplified diagnostic/monitoring instrument for use in primary screening for sleep-disordered breathing (SDB) has been desired. This study was designed to assess...     

Identification and characterization of quantitative trait loci for root elongation by using introgression lines with genetic background of Indica-type rice variety IR64

The root is the sole organ taking up water and nutrients from soils. Hence, root system architecture (RSA) is important for enhancing high-level and stable rice (Oryza sativa L.) production. However, the genetic improvement of RSA has received less attention than yield and yield components. Here, we aimed to identify and characterize quantitative trait loci (QTLs) for RSA by determining the maximum root length (MRL) of seedlings grown hydroponically under various concentrations of NH₄ ⁺. We used a total of 280 introgression lines (ILs) with an Indica-type variety IR64 genetic background, consisting of ten sibling ILs groups, to detect the QTLs. Greater variation of MRL was found in three sibling ILs groups. In total, five QTLs were detected by single marker analyses: two each on chromosomes 5 and 6 and one on chromosome 7. Among them, the most effective QTL was detected on a segment derived from IR69093-41-2-3-2 (YP5), which was localized to the long-arm of chromosome 6. The QTL, designated as qRL6.4-YP5, concerned in root elongation. MRL and total root length of a near-isogenic line (NIL) for qRL6.4-YP5 were significantly (15.2–24.6 %) higher than those of IR64 over a wide range of NH₄ ⁺ concentrations. Root number and weight of the NIL were the same as those of IR64. These results indicated that qRL6.4-YP5 was a constitutive QTL for root length in response to change in nitrogen concentrations. To enhance yield potential by improving RSA, qRL6.4-YP5 might help to improve root development in rice molecular breeding programs with marker-assisted selection.     

Structural Property of DNA That Migrates Faster in Gel Electrophoresis,as Deduced by CD Spectroscopy

Bent DNAs are known to migrate slower than ordinary DNA in non-denaturing polyacrylamide gel electrophoresis. In contrast, several satellite DNAs have been shown to migrate fast. The structural property that causes the fast migration, however, is not clarified so far on molecular basis. We have investigated the structural property of a satellite DNA, which contains consecutive purine sequences and migrates faster in gel, by CD spectroscopy. Partial formation of an A-form–like structure has been suggested. Reduction in DNA length due to the formation of the A-form–like structure may be responsible for the fast migration. The pronounced rigidity of DNA may also contribute to the behavior.