The conventional short-circuiting technique under-short-circuits most epithelia

Summary The relationships among ion current, membrane potential difference, and resistance of an epithelium are studied. The short-circuit technique introduced by Ussing and Zerahn does not completely short circuit the epithelium if the series resistance parallel to the cell layer between the voltage electrodes is not properly compensated. The residual potential difference across the epithelial cell layer in the short-circuit state is proportional to both the measured short-circuit current and the resistance of the diffusion barriers not compensated. In the conventionally short-circuited small intestinal mucosa the villus and crypt areas are hypo-polarized to different degrees rather than simultaneously hyper- and hypo-polarized. Short-circuiting the whole tissue reduces but does not abolish the passive net ion movement across the tissue. Measurements of the electrical properties of the whole and denuded rat distal small intestine in HCO₃-Ringer solution containing 10mm glucose reveal that the measured short-circuit current has under-estimated approximately 33% of the true short-circuit current and that the passive net Na flux from serosa to mucosa and Cl flux from mucosa to serosa are not negligible in the short-circuit state.     

Release of arachidonate from diglyceride in human platelets requires the sequential action of a diglyceride lipase and a monoglyceride lipase

Release of arachidonate from 2-arachidonyl diglyceride by human platelet microsomes was investigated. Diglycerides labeled with ¹⁴C-stearate at sn-1 and with ³H-arachidonate at sn-2 were used as a substrate for microsomal diglyceride lipase. Diglyceride was deacylated first at sn-1 as evidenced by the accumulation of 2-arachidonyl monoglyceride but not of 1-stearoyl monoglyceride. Subsequent release of arachidonate from monoglyceride required the action of a monoglyceride lipase. Studies on substrate specificity indicated that diglyceride lipase utilized 2-arachidonyl diglyceride as the best substrate.     

Triphasic concentration effects of gentamicin on activity and misreading in protein synthesis.

Gentamicin is shown to exert a triphasic concentration effect on peptide synthesis in vitro with natural messengers. Low concentrations (up to 2 micron) caused slowing and a decrease in total synthesis, but little misreading (assayed with extracts lacking Glu-tRNA); the inhibition was greater with an initiating system (with phage RNA as messenger) than with pure chain elongation on purified endogenous polysomes of Escherichia coli. Moderate concentrations (up to 100 micron) slowed synthesis less, markedly increased its duration in the noninitiating system, and strongly stimulated misreading; at optimal concentrations total synthesis was even greater than normal. Moreover, with phage RNA these concentrations increased the synthesis of large polypeptides. We conclude that binding of gentamicin to its first site causes inhibition but little misreading; binding to additional site(s) partly reverses the inhibition by first-site binding and markedly stimulates misreading, and the misreading appears to favor "readthrough" of termination codons. In the third phase (greater than 100 micron) synthesis is slowed again but the pattern of misreading does not appear to be altered; this effect need not involve a specific further action on the ribosome.     

Hydrolase production by Aspergillus niger in solid-state cultivation

Summary A production of macerating enzymes which liquefy and hydrolyze the mandarin orange peel was studied in a solid state cultivation of Aspergillus niger on wheat bran substrate. Solid state cultivation in a 2 drum fermenter capable of interchangeable operation under dynamic or static conditions were carried out maintaining the moisture content of the substrate at 32, 39, 46, 56, 67, and 74%. Biomass grown on the solid substrate was estimated on the basis of a constant value of glucosamine content of A. niger, 50 mg glucosamine/g cell. A linear relationship between oxygen uptake rate and growth rate observed in all the experiments gave an oxygen growth yield, Y_X/O, of 28.5 g cell/mol O₂. The rate of macerating enzyme formation was also in proportion to the growth rate irrespective of the difference of the moisture content of the substrate.The enzyme accumulation on the solid substrate, the growth rate and oxygen uptake rate were maximum when the moisture content of the substrate was maintained at ca. 56% ascending from 32 to 56 and descending from 56 to 74.     

Light scattering and turbidity measurements on lipid vesicles

The dynamic behaviour of model membranes in the form of sonicated liposomes in excess water was studied by means of 90 °C light scattering and turbidity measurements. Computer calculations based on the Rayleigh-Gans theory of light scattering were used to estimate the average size of lipid vesicles dispersed in water, taking into account the various structures of the vesicles. Normal reversible changes in the scattered light intensity and turbidity with temperature could be accounted for mainly by the change in the refractive index of the lipid and irreversible anomalous changes were explained on the basis of fusion of smaller aggregated vesicles.     

Primary structure of streptococcal proteinase. III. Isolation of cyanogen bromide peptides: complete covalent structure of the polypeptide chain.

The following sequence has been derived for streptococcal proteinase. (See article). The sequence permits the assignment of the single cysteine residue essential for catalytic action at position 47 from the NH2 terminus of the protein. The tryptophan residue at the binding site of the enzyme is at position 214. A histidine residue at position 195 has been assigned as the catalytically important entity in the molecule. Streptococcal proteinase and papain, an enzyme with similar properties, are compared with respect to structure and function.     

A visit to the zoos and aquariums in Northern Japan

For their trip to the National Parks in Hokkaido the authors also included in their schedule visits to the zoos and aquariums in Northern Japan. Their tight scheduled tour started at the Aquamarine Fukushima, which was after the large tsunami rebuilt and re-opened in July 2011. They continued with a visit to the Kamo Aquarium, which is famous for its unique and large jellyfish exhibition. On Hokkaido Island they visited the smaller zoos in Kushiro and Obihiro with a good collection of native Hokkaido animal species. Included was also the Asahiyama Zoo, which is at the moment one of the most popular zoos in Japan. It is well-known for its innovative enclosures for seals and penguins. The Sapporo Maruyama Zoo and the Chitose Salmon Aquarium were the last highlights of this tour. The themes and animal collections of these different zoos and aquariums are described. The general situation for the northern zoos and aquariums is quite different compared to the institutions in the southern parts of the country and entirely to the zoos in the large city areas like Tokyo, Osaka and Nagoya. Here in the northern zoos and aquariums many native animal species and subspecies are kept and often successfully bred.     

Pseudo-random mating systems for 3-allele loci

A random mating population attains equilibrium by the Hardy-Weinberg law. By demonstrating some simple examples for 2-allele loci, Li (1988) showed that a nonrandom mating population of certain mating patterns may also attain equilibrium. He called such a type of population a pseudo-random mating population. Tai (1990), then, gave a generalized representation of these pseudo-random mating systems. In this paper the clear patterns of pseudo-random mating behavior for a 3-allele locus are derived. Both autosomal and sex-linked systems are discussed. The study of these mating patterns provides a way to understand the complicated mating system of a population, which usually is only with difficulty realized through sampled individuals from that population.     

Systematic analysis of multigene predictors in gastric cancer exploiting gene expression signature

Gastric cancer (GC) is the second most common cause of cancer death worldwide but could be more curable if diagnosed at an earlier stage. At present, the capability to predict the efficaciousness of molecular diagnosis for GC for each patient remains elusive. The purpose of this study was to identify tumor biomarkers through systems analysis of multigene predictors exploiting the available data resource. In this study, we investigated the top 10% overexpressed genes in GC from five data sets of the Oncomine platform, with 265 GC samples versus 174 normal gastric mucosa samples. Sixteen candidate genes were identified as predictors of GC, of which 14 genes were verified through the comparison of expression levels in specimens from normal (chronic gastritis, 21 samples) and GC groups (38 samples). In addition, unique molecular portraits of diffuse adenocarcinoma (DA), intestinal adenocarcinoma (IA), and mixed adenocarcinoma (MA) were studied through Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analysis, where DA showed higher extracellular matrix alteration while IA and MA showed higher cell-cycle alteration than other types. We also found that the elevated expressions of genes during GC progression were independent of gene mutations, and high core-binding factor subunit β expression is correlated with a high overall survival rate in GC patients. Our research may provide an efficient clinical diagnosis of GC at an early stage with high accuracy and thus help improve the overall survival rate through early therapeutic interventions.