Asymmetric transport of D-glucose anomers across the human erythrocyte membrane

The anomeric preference in the influx and efflux of D-glucose across the human erythrocyte membrane was studied. beta-D-Glucose was transported 1.5 times faster than alpha-D-glucose into the cells, when washed cells were incubated at 20 degrees C in medium containing either alpha- or beta-D-glucose (100 mM). On the other hand, no difference between half-times of efflux of the two anomers was distinguishable. The result demonstrates the presence of influx-efflux asymmetry in anomeric preference in D-glucose transport across the human erythrocyte membrane, and is consistent with the view (Barnett et al., Biochem. J. 145, 417-429, 1975) that the C-1 hydroxyl group of D-glucose interacts with the D-glucose transport protein only in the influx, but not in the efflux.     

Cloning and sequencing of a ligninase gene from a lignindegrading basidiomycete,Phanerochaete chrysosporium

Summary A ligninase gene has been cloned from a Phanerochaete chrysosporium genomic DNA library. Nucleotide sequencing of the gene has revealed that the ligninase structural gene contains 1116 bp of the protein-encoding sequence, of which 84 bp encode the signal peptide. The protein-encoding sequence is interrupted by eight introns which conform to the universal G-T/A-G splicing rule observed for the 3 and 5 intron boundaries. The putative eukaryotic regulatory sequences, i.e. CAAT and TATA box-like sequences, are present in the 5 flanking region.     

Levels of IAA, Cytokinins, ABA and Ethylene in Rice Plants as Affected by a Gibberellin Biosynthesis Inhibitor, Uniconazole-P.

Effects of uniconazole-P, a triazole-type growth retardant,on endogenous levels of IAA, cytokinins, ABA and ethylene inrice seedlings were investigated. Endogenous levels of IAA andABA were similar between control and uniconazole-P-treated riceshoots. Evolution of ethylene was promoted slightly, being 1.8times greater under 0.3 ppm uniconazole-P treatment than thatof control. The most obvious effect was the increase of trans-Zand trans-RZ in shoots. Shoots treated with uniconazole-P (10mg/m² nursery box) contained 3.4 times and 3 times more trans-Zand trans-RZ than control, respectively. No significant differencesof cytokinin levels were recognized in roots except for cis-RZ.The increase of ethylene and active forms of cytokinins, andthe decrease of gibberellin in the shoots may be the basis forphysiological phenomena caused by uniconazole-P, namely thepromotion of flowering in woody plants and the enhancement offemaleness in cucumber. (Received September 9, 1987; Accepted October 20, 1987)     

A Comparative Study of the Structures of {alpha}-Glucans from Suspension-Cultured Nonglutinous and Glutinous Rice Cells

-Glucans (average mol wt, 1.3 ? 10⁴) extracted with perchloricacid from 8-day-old suspension-cultured nonglutinous (var. Sasanishiki)and glutinous rice (var. Miyakogane) cells were compared. Theresults of hydrolysis by alpha;-, ß- and iso-amylasesand methylation analysis of the -glucans suggested that theirbasic structures are almost the same. These -glucans are highly-branchedpolysaccharides with an average chain length of about 9–10,with exterior and interior chain lengths of about 6–7and 2–3, respectively. ¹Current address: Laboratory of Food Science, Faculty of Education,Hirosaki University, Hirosaki, Aomori 036, Japan. (Received April 27, 1987; Accepted March 2, 1988)     

Monoclonal Antibodies Specific for NADH-Ferricyanide Reductase Domain of Spinach Leaf Nitrate Reductase

Two monoclonal antibodies, 17(3)9 and 36(79)4, were preparedagainst nitrate reductase from Spinacia oleracea L. leaves.An enzyme-linked immunosorbent assay showed that 17(3)9, butnot 36(79)4, reacted more strongly to heat-denatured than nativeantigen. These antibodies inhibited NADH-nitrate reductase aswell as its various partial activities including reduced methylvilogen-nitrate reductase, reduced flavin mononucleotide-nitratereductase and NADH-cytochrome c reductase activities, but notNADH-ferricyanide reductase activity. Immunoblotting after electrophoreticseparation of nitrate reductase fragments obtained by Staphyrococcusaureus V8 protease digestion of native enzyme revealed thatthe two monoclonal antibodies bind to different epitopes locatedon the 28 kDa of the NADH-ferricyanide reductase domain. (Received October 2, 1987; Accepted June 9, 1988)     

Adherence of streptococci to surface-modified glass

Four types of surface-modified glass were prepared. Aminopropyl glass was prepared by alkylsilylation of glass slides with gamma-aminopropyltriethoxysilane. This glass carries primary amino groups which may be protonated at pH 7.2. Owing to the presence of both positively charged ions and hydrophobic ethoxyl groups, the glass is considered to be amphipathic. Three other types of surface-modified glass slides were prepared from aminopropyl glass by forming Schiff's bases with three aldehydes: glucose, glyoxylic acid and hexanal. The aldehyde-treated slides were subsequently reduced using sodium borohydride. Thus, the surface of the glass was rendered hydrophilic, ampholytic or hydrophobic, respectively. The adherence of two Streptococcus sanguis strains and two Streptococcus mutans strains to the surface-modified glass slides was studied. Different strains showed differences in adherence to these slides depending on their physico-chemical surface properties. For S. sanguis ATCC 10556, hydrophobic bonds seemed to be most important, while in S. mutans OMZ 176, ionic interactions made the highest contribution to adhesion. Hydrogen bonds seemed to contribute least to adherence.     

Morphology and Taxonomy of <Emphasis Type="Italic">Apristurus longicephahis</Emphasis> (Lamniformes,Seyliorhinidae)

Data on the individual variation and changes with growth in proportions and morphology are presented for the poorly known Apristurus longicephalus, and compared with those of other species. A. longicephalus is concluded to be a distinct species without synonyms, characterized by its long snout, widely separate nostrils, long caudal fin, short abdomen, very sparse teeth, and low number of monospondylous vertebrae. It is a species of small size, maturing at about 42 cm in total length.     

Scale Growth and Squamation Chronology for the Laboratory-Reared Hermaphroditic Fish <Emphasis Type="Italic">Rivulus marmoratus</Emphasis> (Cyprinodontidae)

Scale morphology, growth and the squarnation chronology are described for the hermaphroditic fish Rivulus marmoratus reared in the laboratory. The scales are round or oval shaped cycloid type, and their sizes are about 0.3–1.0 mm in diameter. The number of ridges increases more rapidly relative to the body growth of the fish in early stages, but this increase is proportionate to growth subsequently. Three loci of scale development have been identified. The scales first appeared on the center of the parietal region at 8 days after hatching. The second locus of scale formation was on the lateral line of the posterior end of the caudal peduncle. A third locus was later observed on the lower right corner of the operculum: The final squamation was completed at 6 weeks after hatching.     

Morphological differentiation of endothelial cells co-cultured with astrocytes on type-I or type-IV collagen

Summary In this study bovine aortic endothelial cells were co-cultured with astrocytes from fetal Wistar Kyoto rats. Endothelial cells growing on type-I collagen, development. Although some cells appeared to be mature, horseradish peroxidase penetrated within 1 min of incubation through the intercellular junctions of these endothelial elements maintained on type-I collagen. In contrast, endothelial cells on type-IV collagen, co-cultured with astrocytes, were well developed; their intercellular junctions were well established, and plasmalemmal vesicles reduced in number. As a result, horseradish peroxidase was unable to penetrate through the endothelial cells grown on type-IV collagen and co-cultured with astrocytes because of the reduced extent of the junctional and vesicular transport. These findings reveal that (1) type-IV collagen is essential for the differentiation of endothelial cells, (2) endothelial cell-astrocyte interactions occur during co-culture, and (3) endothelial permeability depends on astrocyte-produced factors, in addition to type-IV collagen.     

Effector molecules from antitumor macrophages induced with OK-432 and cyclophosphamide

Summary The present study was designed to determine whether antitumor activity of macrophages induced with OK-432 and cyclophosphamide was mainly dependent on their ability to produce a soluble factor, that is,l-arginine-dependent nitric oxide as measured by nitrite concentration. Nitrite production by peritoneal macrophages from NIH Swiss mice pretreated with OK-432 (125 KE/kg) i.p. twice at 1-week intervals and with cyclophosphamide (200 mg/kg) i.p. 2 days before the second OK-432 treatment, increased with time for 24 h, and proportionally depended on macrophage numbers. Nitrite production was inhibited by actinomycin D and puromycin but not by mitomycin C.N ^G-Monomethyl-l-arginine, a specific competitive inhibitor ofl-arginine-dependent nitric oxide synthesis, also inhibited production. There was a close correlation between nitrite production and antitumor activity in macrophages from mice pretreated with either OK-432 and cyclophosphamide, OK-432, or thioglycolate broth. OK-432 increased both nitrite production and antitumor activities when added to the macrophage from mice pretreated with OK-432 but not with thioglycolate broth. Both activities of macrophages from mice pretreated with OK-432 and cyclophosphamide were enhanced with increasing concentrations ofl-arginine (0.125–1 mM) in the culture medium.d-Arginine, however, did not substitute forl-arginine. Neither activity was affected by contact between the macrophage and the EL4 cell. The macrophage showed antitumor activity through a membrane filter though the activity was greatly reduced. This antitumor activity of macrophages through a membrane was also inhibited byN ^G-Monomethyl-l-arginine, and increased by OK-432. However, conditioned media, obtained by culturing macrophages induced with OK-432 and cyclophosphamide, inhibited growth of EL4 cells. This activity was carried out by dialysable and non-dialysable factors. One of the dialysable factors was nitrite, an oxidized product of nitric oxide. The antitumor activity of non-dialysable factors was heat-stable and production of factors was increased byN ^G-Monomethyl-l-arginine and OK-432. Also, non-dialysable factors increased both antitumor and nitrite production activities of OK-432-elicited macrophages, when incubated with factors. Such activity of factors was also heat-stable. The production of factors increased with incubation time of macrophages, and was not inhibited byN ^G-Monomethyl-l-arginine. These results indicate that in vitro antitumor activity of macrophages induced with OK-432 and cyclophosphamide was mainly dependent onl-arginine-dependent nitric oxide, and that macrophageassociated soluble factors other than nitric oxide were also needed to inhibit fully tumor growth in vitro.