Volutin as a Substrate of the Gram Reaction

A modified Gram procedure, with the use of an extremely diluted or acidified crystal violet solution, stained only volutin in contrast with nonstaining of the rest of cell in Gram-positive bacteria. The substrate of the Gram reaction is not only a ribonucleic acid-magnesium-protein complex in cytoplasm (Henry and Stacey 1946), but also a metaphosphate-ribonucleic acid complex in volutin and deoxyribonucleic acid in nuclei in Gram-positive cells. The isoelectric-point theory and permeability theory of the Gram stain are unsupported by the experiments.     

The Formation of Higher Alcohols in the Fermentation of Amino Acids by Yeast

It was confirmed that washed yeast cells produced isobutanol from α-acetolactic acid which was presumed as the intermediate in the synthetic pathway of isobutanol from alanine described in the previous report. At the same time α-ketoisovaleric acid was detected in the fermented solution, which seemed to support this scheme. The effects of various fermentation conditions upon the formation of isobutanol were discussed.     

Properties and Transglycosylation Reaction of a Chitinase from Nocardia orientalis

The hydrolytic products of a chitinase purified from Nocardia orientalis were examined on reduced (GIcNAc)_n(n = 2~6). The rate of hydrolysis on reduced (GlcNAc)₄^₆ increased with increasing chain-length of A-acetylglucosamine residues, but the enzyme did not act on reduced (G1cNAc)₂ or reduced (GlcNAc)₃. Based on the analysis of the frequency distribution of bond cleavage on PNP-(GIcNAc)?(n = 2 ~ 5) in the initial hydrolysis, the enzyme was shown to release predominantly (G1cNAc)₂ from the nonreducing end of each substrate. The enzyme, which is essentially a hydrolase, also catalyzed a transglycosylation reaction in an excess of (GlcNAc)₄ as an initial substrate. In this case, the addition of ammonium sulfate to the reaction system resulted in a significant increase in (G1cNAc)₆ production. The yield of the hexasaccharide was about 34% of the chitinase-catalyzed net decrease of (GlcNAc)₄. The rate of the transglycosylation in the presence of ammonium sulfate greatly depended on the salt concentration, the temperature, and the substrate concentration.     

Out of the Orient: Post‐Tethyan transoceanic and trans‐Arabian routes fostered the spread of Baorini skippers in the Afrotropics

The origin of taxa presenting a disjunct distribution between Africa and Asia has puzzled biogeographers for more than a century. This biogeographic pattern has been hypothesized to be the result of transoceanic long‐distance dispersal, Oligocene dispersal through forested corridors, Miocene dispersal through the Arabian Peninsula or passive dispersal on the rifting Indian plate. However, it has often been difficult to pinpoint the mechanisms at play. We investigate biotic exchange between the Afrotropics and the Oriental region during the Cenozoic, a period in which geological changes altered landmass connectivity. We use Baorini skippers (Lepidoptera, Hesperiidae) as a model, a widespread clade of butterflies in the Old World tropics with a disjunct distribution between the Afrotropics and the Oriental region. We use anchored phylogenomics to infer a robust evolutionary tree for Baorini skippers and estimate divergence times and ancestral ranges to test biogeographic hypotheses. Our phylogenomic tree recovers strongly supported relationships for Baorini skippers and clarifies the systematics of the tribe. Dating analyses suggest that these butterflies originated in the Oriental region, Greater Sunda Islands, and the Philippines in the early Miocene c. 23 Ma. Baorini skippers dispersed from the Oriental region towards Africa at least five times in the past 20 Ma. These butterflies colonized the Afrotropics primarily through trans‐Arabian geodispersal after the closure of the Tethyan seaway in the mid‐Miocene. Range expansion from the Oriental region towards the African continent probably occurred via the Gomphotherium land bridge through the Arabian Peninsula. Alternative scenarios invoking long‐distance dispersal and vicariance are not supported. The Miocene climate change and biome shift from forested areas to grasslands possibly facilitated geodispersal in this clade of butterflies.     

Recombinant expression and redox properties of triheme c membrane-bound quinol peroxidase

The qpo gene of Aggregatibacter actinomycetemcomitans encodes a triheme c -containing membrane-bound enzyme, quinol peroxidase (QPO) that catalyzes peroxidation reaction in the respiratory chain and uses quinol as the physiological electron donor. The QPO of A. actinomycetemcomitans is the only characterized QPO, but homologues of the qpo gene are widely distributed among many gram-negative bacteria, including Haemophils ducreii, Bacteroides fragilis , and Escherichia coli . One-third of the amino acid sequence of QPO from the N-terminal end is unique, whereas two-thirds of the sequence from the C-terminal end exhibits high homology with the sequence of the diheme bacterial cytochrome c peroxidase. In order to obtain sufficient protein for biophysical studies, the present study aimed to overproduce recombinant QPO (rQPO) from A. actinomycetemcomitans in E. coli . Coexpression of qpo with E. coli cytochrome c maturation ( ccm ) genes resulted in the expression of an active QPO with a high yield. Using purified rQPO, we determined the midpoint reduction potentials of the three heme molecules.     

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.