Light-induced potential and current across a large bacteriorhodopsin-asolectin planar membrane stabilized on a polyacrylamide gel surface

A phospholipid bilayer membrane was spread from an organic solvent solution between a polyacrylamide gel surface and an aqueous buffer solution. The membrane was quite similar to the conventional black lipid membrane, but was of a large size and was stable since it was supported on the gel surface. Bacteriorhodopsin, impregnated into the membrane, generated membrane potential and current upon illumination. The induced current was large, and this was attributed to the large area of the present membrane. Remarkable responses of the light-induced potential and current were also observed with a thick layer of organic solvent containing phospholipids. The effects of applied membrane potential, carbonylcyanide-m-chlorophenyl hydrazone (CCCP) and gramicidin were examined on these photoresponses. Steady-state current, which is due to protons flowing through the membrane, was enormously enhanced by applying membrane potential opposite to the photopotential or by adding gramicidin to the membrane-forming solution.     

Purification and Characterization of Membrane Protein (90 kDa) from Mycoplasma salivarium,Which Binds Immunoglobulin (Ig) G Fc Fragment

A 90 kDa protein of Mycoplasma salivarium was released from cell membranes of the organism with Triton X-100 and purified by ion-exchange chromatography and chromatofocusing. The protein was eluted at pH 5.5 by chromatofocusing. The protein was shown to react with the Fc fragments of IgG from human and nine different animal species and did not distinguish between IgG from different species, while protein A, tested for comparative purposes, displayed a strong specificity for human and swine IgG. Furthermore, the protein reacted with antigen specific goat IgG (specific for gamma chains of human IgG), sheep red blood cells (SRBC) sensitized with rabbit antiserum to SRBC, that is, the Fc part of rabbit IgG, and concanavalin A as well. These findings may suggest that the protein is a lectin which binds the carbohydrate moiety of the Fc part of IgG.     

Identification of Influenza C Virus Phosphoproteins

The HMV-II cells infected with influenza C virus were labeled with inorganic [³²P]phosphate to identify phosphorylated proteins. Analysis by radioimmunoprecipitation with antiviral serum or monoclonal antibodies revealed that three major structural proteins of the virus, hemagglutinin-esterase (HE), nucleoprotein (NP), and matrix protein (M1) are all phosphorylated in both infected cells and virions. It was also observed that, in the presence of trypsin (10 μg/ml), the unphosphorylated form of the HE glycoprotein was cleaved efficiently whereas the phosphorylated form was not, raising the possibility that phosphorylation of HE may influence its susceptibility to degradation by proteolytic enzymes.     

Histochemical examination of cathepsin K,MMP1 and MMP2 in compressed periodontal ligament during orthodontic tooth movement in periostin deficient mice

The purpose of this study was to investigate immunolocalization of collagenolytic enzymes including cathepsin K, matrix metalloproteinase (MMP) 1 and 2 in the compressed periodontal ligament (PDL) during orthodontic tooth movement using a periostin deficient (Pn-/-) mouse model. Twelve-week-old male mice homozygous for the disrupted periostin gene and their wild type (WT) littermates were used in these experiments. The tooth movement was performed according to Waldo’s method, in which elastic bands of 0.5 mm thickness were inserted between the first and second upper molars of mice under anesthesia. At 1 and 3 days after orthodontic force application, mice were fixed with transcardial perfusion of 4 % paraformaldehyde in 0.1 M phosphate buffer (pH 7.4), and the first molars and peripheral alveolar bones were extracted for histochemical analyses. Compared with WT mice, immunolocalization of cathepsin K, MMP1 and MMP2 was significantly decreased at 1 and 3 days after orthodontic tooth movement in the compressed PDL of Pn-/- mice, although MMP1-reactivity and MMP2-reactivity decreased at different amounts. Very little cathepsin K-immunoreactivity was observed in the assessed regions of Pn-/- mice, both before and after orthodontic force application. Furthermore, Pn-/- mice showed a much wider residual PDL than WT mice. Taken together, we concluded that periostin plays an essential role in the function of collagenolytic enzymes like cathepsin K, MMP1 and MMP2 in the compressed PDL after orthodontic force application.     

Ancient Mitochondrial DNA Reveals the Origin of Sus scrofa from Rebun Island, Japan

The Kabukai A site (5 to 8C A.D.) of the Okhotsk cultural area is on Rebun Island, a small island near the coast, north–northwest of Hokkaido, Japan. Specimens of Sus scrofa, called the Sakhalin pig, were discovered in five cultural layers at the Kabukai A site. Ancient DNA was extracted from the remains of 42 Sakhalin pig bones. Thirty-nine nucleotide sequences of the 574-bp mitochondrial DNA control region, estimated to have originated from at least 21 individuals, were amplified and analyzed phylogenetically. Nine distinct haplotypes (A1, A2, A3, B1, B2, C1, C2, D1, and D2) from this site were classified into four haplotype groups (A, B, C, and D) by parsimonious network analysis. Phylogenetic analysis of 9 ancient and 55 modern haplotypes indicated that the population of Sakhalin pigs at the Kabukai A site belonged to two distinct clusters; haplotype groups A and B formed a cluster comprised only of themselves, and haplotype groups C and D belonged to the cluster of one of the two genetic groups of Japanese wild boars uniquely distributed in the western part of Japan, including one northeast Mongolian wild boar. Analysis of the haplotype distribution among three archaeological sites and their historical transitions among the five layers reflecting the cultural periods at the Kabukai A site suggests that the Sakhalin pig populations were introduced from Sakhalin island and the Amur River basin in the northeastern Eurasian continent together with some cultural influences. Received: 18 April 2000 / Accepted: 24 November 2000     

Novel Method of Lactic Acid Production by Electrodialysis Fermentation

In lactic acid fermentation by Lactobacillus delbrueckii, the produced lactic acid affected the lactic acid productivity. Therefore, for the purpose of alleviating this inhibitory effect, an electrodialysis fermentation method which can continuously remove produced lactic acid from the fermentation broth was applied to this fermentation process. As a result, the continuation of fermentation activity was obtained, and the productivity was three times higher than in non-pH-controlled fermentation. In electrodialysis fermentation, the amount of produced lactic acid was 82.2 g/liter, which was about 5.5 times greater than that produced in non-pH-controlled fermentation. It was concluded that these good results were obtained on account of alleviating the lactic acid inhibitory effect by electrodialysis fermentation. However, the fouling of anion-exchange membranes by cells was observed in electrodialysis fermentation.     

Studies on Oxidation-Reduction Potentials (ORP) of Microbial Cultures

Aerobacter aerogenes No. 505 isolated from soil by Uyeda produced l-valine extracellularly by an aerobic shaking culture. Under anaerobic conditions the production of this amino acid was inhibited while lactic acid as well as a small amount of alanine were produced. The changes in ORP during the incubation under both conditions were investigated. When l-valine was the main product under aerobic conditions the ORP showed a constant value (rH 8.0) from 16 to 40 hr after inoculation. But when lactic acid was the main product and alanine was produced as the only amino acid under anaerobic conditions, the ORP drifted to rH 0 (zero). The phenomenon of the conversion of fermentation was shown clearly by the ORP of the culture broth.

The endpotentiai of lactic acid fermentation by Rhizopus G-36 was rH 13 to 14 when measured in the presence of trace amounts of redox dye mixtures. Without dyes, the rH was 18 to 22 and this fungal culture was slower in reaching endpotentials than bacterial cultures. It was postulated that the amount of redox substances exhibiting electromotive activity was not sufficient in this culture.

rH value 13 to 14 was not obtained under such conditions that lactic acid was not produced; that is in a medium with higher concentration of the nitrogen source in the presence of Fe²⁺ and Zn²⁺, or in a medium containing acetate in place of glucose as the carbon source.

Mycelia of Rhizopus G-36 after 36 hr-culture produced lactic acid even in the absence of oxygen. But unexpectedly, the ORP under anaerobic secondary culture was exactly the same as that in the aerobic shaking culture (rH 13.2).

A method for homogenization of the culture without secondary oxidation was improved. The ORP of anaerobically homogenized cultures was rH 11, and was thought to be due to the activities of all redox systems in the mycelium.

The respiration system of this strain was switched from cytochrome system to flavin system at the point of change in KGN-sensitivity. The ORP of this strain may be influenced by respiration through the flavin system.     

Studies on Oxidation-Reduction Potentials (ORP) of Microbial Cultures

At maximum production of l-glutamic acid, the oxidation-reduction potential of the culture broth in l-glutamic acid fermentation showed a stable value of 9.0 to 9.6 as rH value. When biotin concentration in the medium was high (40γ/liter), the production of l-glutamic acid decreased, and the rH was 8.0 and it was out of accordance with that of the control (biotin-poor; 2γ/liter). Under “less-aerobic” conditions, its rH rose to 10.4.

From these results, it was concluded that the rH during maximum production of l-glutamic acid showed a stable value affected actively by the redox system, l-glutamic acid/α-ketoglutaric acid and      

Bacteriophages of Clostridium saccharoperbutylacetonicum

The morphological properties of the twelve previously described HM-phages were examined by electron microscopy. Specimens were prepared by air-drying and shadow-casting method using purified phage suspensions. As a result, the HM-phages were classified into three morphologically distinct groups, 1, 11 and 111. Group 1 phages were HM 1, HM 2, HM 8, HM 9, HM 10, HM 11 and HM 12. These phages had a spherical head about 100 mμ in diameter and a rudimentary tail. Group 11 phages were HM 3, HM 4, HM 5 and HM 6. These phages had a spherical head about 100 mμ in diameter and a tail with contractile sheath, and the normal tail of these phages was about 100 mμ in length, and the contracted sheath was about 50 mμ in length, Group 111 phage was HM 7 alone. This phage had a spherical head about 120 mμ in diameter and a relatively long tail about 350 mμ in length.