The 27-kD diphtheria toxin receptor-associated protein (DRAP27) from vero cells is the monkey homologue of human CD9 antigen: expression of DRAP27 elevates the number of diphtheria toxin receptors on toxin- sensitive cells

Diphtheria toxin (DT) receptor associates with a 27-kD membrane protein (DRAP27) in monkey Vero cells. A cDNA encoding DRAP27 was isolated, and its nucleotide sequence was determined. The deduced amino acid sequence revealed that DRAP27 is the monkey homologue of human CD9 antigen. DRAP27 is recognized by CD9 antibodies. A human-mouse hybrid cell line (3279-10) possessing human chromosome 5, sensitive to DT, but not expressing CD9 antigen, was used for transfection experiments with DRAP27. When the cloned cDNA encoding DRAP27 was transiently expressed in 3279-10 cells, the total DT binding capacity was three to four times higher than that of untransfected controls. Transfectants stably expressing DRAP27 have an increased number of DT binding sites on the cell surface. Furthermore, the transfectants are 3-25 times more sensitive to DT than untransfected cells, and the sensitivity of these cells to DT is correlated with the number of DRAP27 molecules on the surface. However, when the cloned cDNA was introduced into mouse cell lines that do not express DT receptors, neither an increased DT binding nor enhancement of DT sensitivity was observed. Hence, we conclude that DRAP27 itself does not bind DT, but serves to increase DT binding and consequently enhances DT sensitivity of cells that have DT receptors. 12 proteins related to DRAP27/CD9 antigen were found through homology search analysis. These proteins appear to belong to a new family of transmembrane proteins.     

cDNA sequence and expression of a phosphoenolpyruvate carboxylase gene from soybean

A full-length cDNA encoding a subunit of phosphoenolpyruvate carboxylase (PEPC) was isolated from a developing seed expression library of the C₃ plant Glycine max. The corresponding mRNA is present at similar levels in leaf, stem, root and developing seed. Two potential start codons exist, and the activity of protein initiated from the first such codon could be subject to regulation by protein kinase. Sequence comparison shows a similar upstream start codon in the case of the Ppc2 gene from Mesembryanthemum crystallinum, previously assumed to lack the sequences necessary for phosphorylation. The soybean encoded protein tends to resemble other C₃-type PEPC proteins more closely than those implicated in C₄ or crassulacean acid metabolism.     

Differences between Lactobacillus casei subsp. casei 2206 and Citrate-Positive Lactococcus lactis subsp. lactis 3022 in the Characteristics of Diacetyl Production

Lactobacillus casei subsp. casei 2206 exhibited much lower levels of diacetyl reductase activity than Citr⁺Lactococcus lactis subsp. lactis 3022 but two-, three-, and more than eightfold-higher levels of diacetyl synthase, lactate dehydrogenase, and NADH oxidase activities, respectively. A requirement for metal ions by the diacetyl synthases in both species was observed. The extracts of strain 2206 but not strain 3022 produced more diacetyl from pyruvate when the reaction for diacetyl synthase was aerated than when it was conducted statically.     

Methylene blue inhibits hypoxic cerebral vasodilation in awake sheep.

Cerebral vasodilation in hypoxia may involve endothelium-derived relaxing factor-nitric oxide. Methylene blue (MB), an in vitro inhibitor of soluble guanylate cyclase, was injected intravenously into six adult ewes instrumented chronically with left ventricular, aortic, and sagittal sinus catheters. In normoxia, MB (0.5 mg/kg) did not alter cerebral blood flow (CBF, measured with 15-microns radiolabeled microspheres), cerebral O2 uptake, mean arterial pressure (MAP), heart rate, cerebral lactate release, or cerebral O2 extraction fraction (OEF). After 1 h of normobaric poikilocapnic hypoxia (arterial PO2 40 Torr, arterial O2 saturation 50%), CBF increased from 51 +/- 5.8 to 142 +/- 18.8 ml.min-1 x 100 g-1, cerebral O2 uptake from 3.5 +/- 0.25 to 4.7 +/- 0.41 ml.min-1 x 100 g-1, cerebral lactate release from 2 +/- 10 to 100 +/- 50 mumol.min- x 100 g-1, and heart rate from 107 +/- 5 to 155 +/- 9 beats/min (P < 0.01). MAP and OEF were unchanged from 91 +/- 3 mmHg and 48 +/- 4%, respectively. In hypoxia, 30 min after MB (0.5 mg/kg), CBF declined to 79.3 +/- 11.7 ml.min-1 x 100 g-1 (P < 0.01), brain O2 uptake (4.3 +/- 0.9 ml.min-1 x 100 g-1) and heart rate (133 +/- 9 beats/min) remained elevated, cerebral lactate release became negative (-155 +/- 60 mumol.min-1 x 100 g-1, P < 0.01), OEF increased to 57 +/- 3% (P < 0.01), and MAP (93 +/- 5 mmHg) was unchanged. The sheep became behaviorally depressed, probably because of global cerebral ischemia. These results may be related to interference with a guanylate cyclase-dependent mechanism.(ABSTRACT TRUNCATED AT 250 WORDS)     

Mechanism in 1,25(OH)2D3-induced suppression of helper/suppressor function of CD4/CD8 cells to immunoglobulin production in B cells

On the basis of previous data that 1,25(OH)2D3 suppressed both helper and suppressor activities of CD4 and CD8 cells in the pokeweek mitogen-stimulated culture, we examined the further effect of 1,25(OH)2D3 on both cells to define how 1,25(OH)2D3 is involved in the deterioration of their functions. 1,25(OH)2D3 suppressed the pokeweed mitogen and phytohemagglutinin-induced DNA synthesis of CD4 and CD8 cells. The suppression by 1,25(OH)2D3 of DNA synthesis was caused by a time lag in reaching maximal response. 1,25(OH)2D3 also suppressed interleukin-2 production of CD4 and CD8 cells. 1,25(OH)2D3 did not, however, affect their interleukin-2 receptor expression detected within 24 hr after phytohemagglutinin stimulation. In addition, 1,25(OH)2D3 failed to suppress DNA synthesis of CD4 and CD8 cells when cultured with a large amount of interleukin-2. Suppression by 1,25(OH)2D3 of proliferation and interleukin-2 production in CD4 and CD8 cells would bring about the decrease of their helper or suppressor functions by inhibiting their expansion or maturation.     

Adductor muscles of the thigh of crab-eating monkeys (Macaca fascicularis)

On the basis of 44 hindlimbs of 14 male and 14 female crab-eating monkeys (Macaca fascicularis), the morphology of the adductor muscles of the thigh was described and some functional indices were calculated. The results obtained from this study agreed generally with those of otherMacaca species reported by various authors. For the classification and nomenclature of the adductors, the criteria proposed byUhlmann (1967, 1968) was well adapted to the crab-eating monkey. The adductors comprise the m. gracilis, m. pectineus, m. adductor longus, pars longa and pars brevis of m. adductor brevis, pars lata and pars minima of m. adductor magnus and m. obturatorius externus. In males, the adductors are generally inserted further down the femur, and the insertions of pars brevis of the m. adductor brevis and pars minima of the m. adductor magnus have longer attachments to the femur than in females. The arrangement of each adductor muscle and of each fasciculus of a thigh muscle may invoke a principle of organization.     

A respiration-dependent primary sodium extrusion system functioning at alkaline pH in the marine bacterium Vibrioalginolyticus

The membrane potential generated at pH 8.5 by K⁺-depleted and Na⁺-loaded $\text{Vibrio}\text{alginolyticus}$ is not collapsed by proton conductors which, instead, induce the accumulation of protons in equilibrium with the membrane potential. The generation of such a membrane potential and the accumulation of protons are specific to Na⁺-loaded cells at alkaline pH and are dependent on respiration. Extrusion of Na⁺ at pH 8.5 occurs in the presence of proton conductors unless respiration is inhibited while it is abolished by proton conductors at acidic pH. The uptake of α-aminoisobutyric acid, which is driven by the Na⁺-electrochemical gradient, is observed even in the presence of proton conductors at pH 8.5 but not at acidic pH. We conclude that a respiration-dependent primary electrogenic Na⁺ extrusion system is functioning at alkaline pH to generate the proton conductor-insensitive membrane potential and Na⁺ chemical gradient.     

A synthesis of 3′,4-́dideoxykanamycin B

3′,4′-Dideoxykanamycin B, the kanamycin B derivative that is active against resistant bacteria, was prepared from kanamycin B viaN-tosylation, 3′,4′-O-sulphonylation, 3′,4′-unsaturation, and hydrogenation. The unsaturated intermediate was obtained from the 3′,4′-di-O-sulphonyl derivatives by the action of sodium iodide in N,N-dimethylformamide; if zinc dust was added in this reaction, aziridine derivatives were formed, Removal of the tosyl group was successfully performed by using sodium in ammonia-ethylamine.