Reaction of S-(2-amino-2-carboxyethylsulfonyl)-l-cysteine with sulfite: Synthesis of S-sulfo-l-cysteine and l-alanine 3-sulfinic acid and application to the determination of sulfite

A procedure for the simultaneous preparation of S-sulfo-l-cysteine and l-alanine 3-sulfinic acid is described. The method is based on the quantitative reaction between sulfite and S-(2-amino-2-carboxyethylsulfonyl)-l-cysteine. The yield was 95% for S-sulfo-l-cysteine and 91% for l-alanine 3-sulfinic acid. The reaction was also applied to the quantitative determination of sulfite in biological materials. In this procedure, sulfite reacts with S-(2-amino-2-carboxyethylsulfonyl)-l-cysteine. Separation of the reaction product, S-sulfo-l-cysteine, is done by ion-exchange fractionation, and it is determined with acid ninhydrin reagent 2 (M. K. Gaitonde, 1967, Biochem. J.104, 627–663). The recovery was 96.8 ± 0.3%.     

Purification and structural characterization of progastrin-derived peptides from a human gastrinoma

Several peptides derived from the gastrin-predicted preprohormone sequence were isolated from a human gastrinoma by gel permeation, anion exchange, and reverse phase chromatography. The peptides were identified and characterized structurally by a combination of radioimmunoassays, mass spectral analysis, and microsequence analysis. The largest peptide, progastrin-(1-35) (cryptagastrin), extends from the putative processing site for the signal peptidase to the double basic residues adjacent to the amino terminus of gastrin 34. A shorter form of this peptide, progastrin-(6-35) (cryptagastrin-(6-35), was also isolated in smaller amounts. In addition, sulfated and nonsulfated gastrin 17 amides (progastrin-(55-71)) and the glycine-extended nonsulfated gastrin 17 (progastrin-(55-72)) were identified by radioimmunoassay, and their structures were confirmed by mass spectral analysis. Isolation of cryptagastrin indicates that the signal peptide of human preprogastrin contains 21 amino acid residues, and progastrin, therefore, contains 80 amino acids. There is minimal processing of the cryptic peptide preceding the sequence of gastrin 34. An amidated gastrin form larger than gastrin 34 could contain 71 amino acids. No evidence was obtained for processing that would produce gastrins containing more than 34 but less than 71 amino acid residues.     

Halocyamines: novel antimicrobial tetrapeptide-like substances isolated from the hemocytes of the solitary ascidian Halocynthia roretzi

Two novel antimicrobial tetrapeptide-like substances, halocyamine A and B, were isolated from the solitary ascidian Halocynthia roretzi by a procedure including extraction steps, chromatographies on coarse and fine HP-20 columns, and preparative reversed-phase high-performance liquid chromatography. The structures of halocyamine A and B were determined to be L-histidyl-L-6,7-dihydroxyphenylalanylglycyl-6-bromo-8,9-didehy drotryptamine and L-threonyl-L-6,7-dihydroxyphenylalanyl-L-histidyl-6-bromo-8,9- didehydrotryptamine, respectively, by spectral analyses and degradation studies. Besides antimicrobial activities against several kinds of bacteria and yeasts, both of them showed cytotoxic activities against neuronal cells cultured from rat fetal brain, mouse neuroblastoma N-18 cells, and human hepatoma Hep-G2 cells. They were only detected in the "morula"-like cells, which are of the most abundant cell type among the hemocytes of H. roretzi.     

Bleomycin-induced β-lactamase overexpression in Escherichia coli carrying a bleomycin-resistance gene from Streptomyces verticillus and its application to screen bleomycin analogues

Abstract A bleomycin-resistance gene, designated blmA , has been cloned from bleomycin-producing Streptomyces verticillus by Sugiyama et al. (Gene 151 (1994) 11–16). The present study shows that Escherichia coli harboring the blmA -carrying pUC plasmid overproduced β-lactamase, encoded by an ampicillin-resistance gene on the plasmid, when cultured in the presence of bleomycin, which suggests that bleomycin may act as an inducer (or an activator) for the expression of the specific gene in the presence of blmA . We constructed a vector, designated pMAB50, which senses bleomycin and produces a pigment, using blmA and a Streptomyces tyrosinase gene located under the control of β-lactamase promoter: E. coli harboring pMAB50 produced the melanin pigment in the presence of bleomycin-type antibiotics, suggesting that the transformed E. coli can be employed as a reporter organism to screen bleomycin analogues.     

A new approach in the evaluation of chromosome variants in man

Summary Chromosome variants were evaluated on the basis of their DNA-replication pattern (LBA). The size of late-replicating centromeric heterochromatin of chromosomes 2, 5, 6, 7, 8, 10, 11, 12, 17, 18, 19, and 20, i.e., pairs without Q or C (qh) variants, was measured by means of a microdensitometer. The results were expressed in area, related to that of a euchromatic segment of a given chromosome, and were assigned into five classes based on the difference in standard deviation from an average relative size. LBA variants in each of 12 pairs were found in 29%–42% of the chromosomes.     

Intrapopulation genetic variation in the level and rhythm of daily activity in Drosophila immigrans

Genetic diversity within a population, such as polymorphisms and personality, is considered to improve population performance because such intraspecific variations have the potential to alleviate the competition for a limited resource or the risk of predation and sexual harassment at a population level. Variation in the level and rhythm of daily activity in a population could also affect population performance by directly altering ecological, social, and sexual interactions among individuals. However, it remains to be elucidated whether such intra‐population variation in the level and rhythms of daily activity exists in a natural population. Here, we investigated the genetic variation in daily activity within a single natural population of Drosophila immigrans. We established 21 isofemale lines from a single natural population and measured larval activity level and the level and daily pattern of adult activity over a 24 hr period. Larval activity level significantly varied among isofemale lines. Likewise, the activity level in the adult stage significantly varied among lines. The significant variation was also found in the daily pattern of adult activity; some lines showed greater activity level in the daytime, and others showed greater activity level in the night. Our results consistently suggest that there is a genetic variation in behavioral activity in a natural population, probably contributing to shaping the population performance.     

Time constraints related to sexual maturation and prolonged copulation in the female‐dimorphic damselfly Ischnura senegalensis

Time constraints are critical for reproductive success. To understand the spatiotemporal dynamics of morph frequency in the female‐dimorphic damselfly Ischnura senegalensis, we compared two different morphs for two important time constraints on female reproductive output, i.e. post‐emergence sexual maturation and prolonged copulation. The females of both morphs achieved sexual maturation 4–5 days after emergence, suggesting that the rate of sexual mutation does not result in morph‐specific fitness. The copulation durations declined with the time of onset of copulation in both morphs. Consequently, all copulations terminated at approximately 12:00 hours. Because females show foraging and oviposition activity only after copulation, the copulation duration does not result in morph‐specific time constraints. These two important time constraints do not account for morph‐specific reproductive success and do not affect the evolutionary equilibrium of morph frequency in I. senegalensis.     

Variation in life-history traits of male Japanese fluvial sculpin Cottus pollux in relation to nest abundance along a stream course

Life-history theory predicts the occurrence of variation in the life-history traits of fish populations under different environmental conditions; however, most studies have focused on such variation between geographically separated populations. We compared breeding characteristics and life-history traits of the Japanese fluvial sculpin (Cottus pollux), a bottom-dwelling nest-holding fish, between two adjacent sites sub-divided by a weir along a stream course in central Japan. Males in the area with a lower abundance of nest sites reached sexual maturity at an earlier age and had a shorter life span than males in the area with sufficient nest abundance. Size-dependent male reproduction was found only in areas with a shortage of nest sites, supporting the assumption of competitive exclusion among males for nests. Females matured at the same age in both sites with no differences in age-specific growth rates and mortality. Our results provide evidence for life-history variation in age and size at maturity and age-specific mortality schedule of males in nest-holding fishes in a single stream population via different sexual selection regimes related to differences in nest abundance between sites.     

Body size and temperature dependence of routine metabolic rate and critical oxygen concentration in larvae and juveniles of the round crucian carp Carassius auratus grandoculis Temminck & Schlegel 1846

Routine metabolic rate (RMR, mgO₂ g^?1 h^?1) and critical oxygen concentration (Pc, a hypoxia tolerance indicator, mgO₂ L^?1) were determined in larvae and juveniles of round crucian carp, Carassius auratus grandoculis Temminck & Schlegel 1846, by measuring oxygen consumption at 15°C, 20°C, and 30°C. In addition, the dependence of RMR and Pc on fish body weight (W, g) and temperature (T, °C) was examined to construct minimal mathematical models. RMR depended on W and showed smaller values in larger individuals. RMR was different among the three temperature conditions and showed higher values at higher temperatures. Pc was significantly related to W and was low in larger individuals; that is, larger individuals had a higher hypoxia tolerance. In contrast, Pc was independent of temperature, implying that seasonal temperature fluctuations do not cause seasonal disequilibrium of hypoxia tolerance in round crucian carp. The RMR and Pc models were RMR = 0.0674W^?0.193e^0.0562T and Pc = 1.35W^?0.107, respectively. The metabolic information clarified in this study is essential for habitat quality assessments and aquaculture management of this species.