Mannose-binding lectin A-deficient mice have abrogated antigen-specific IgM responses and increased susceptibility to a nematode infection

To investigate the role of mannose-binding lectin-A (MBL-A) in protection against infectious disease, MBL-A(-/-)-deficient mice were generated. Using a well-characterized mouse model of human filarial nematode infection, nematode survival and protective immune responses were tested in vivo. Blood-borne Brugia malayi microfilariae survived for significantly longer time periods in MBL-A(-/-) than in wild-type (WT) mice. However, no differences in either splenic cytokine responses or induction of leukocytes in the blood were observed. A profound abrogation of Ag-specific IgM levels was measured in B. malayi-infected MBL-A(-/-) mice, and some IgG isotypes were higher than those observed in WT animals. To establish whether there was a defect in Ab responses per se in MBL-A(-/-) mice or the effect was specific to filarial infection, we immunized these mice with OVA or a carbohydrate-free protein. Significantly, Ag-specific IgM responses were defective to both of these Ags, and Ag-specific IgG responses were largely unaffected. Furthermore, in naive mice, total IgM levels did not differ between MBL-A(-/-) and WT mice. This article describes the first demonstration that MBL-A may function independently of MBL-C and suggests that MBL-A, like other C-type lectins and members of the complement cascade, is intimately involved in the priming of the humoral Ab response.     

Applying Proteolytic Enzymes on Soybean

An indole derivative having blue fluorescence was produced in cooked soybean digested at 37°C for 24 hr with an acid proteinase Molsin (optimum pH: 2.8) from Aspergillus saitoi or a usual acid proteinase pepsin (optimum pH: 1.6) from beef stomach. This indole derivative was identical with a condensation product from l-tryptophan and n-hexanal. Based on MS, NMR, IR and UV spectrometry, the condensation product was identified as l-pentyl-2, 3, 4, 9-tetrahydro-lH-pyrido [3, 4-b]-indole-3-carboxylic acid [trivial name: 1-pentyl-l, 2, 3, 4-tetrahydro-2-carboline carboxylic acid-(3)].

Data were presented of the formation of the above indole derivative and of the resulting consumption of l-tryptophan and n-hexanal.

The possible ocurrence of the formation of Harmala alkaloids, i.e. 2-carboline derivatives, through in vitro digestion of soybean with acid proteinases was discussed.

A carbonyl-trapping ability of l-tryptophan was suggested.     

Genetic analysis of human lymphocyte proteins by two-dimensional gel electrophoresis: 3. Frequent occurrence of genetic variants in some abundant polypeptides of PHA-stimulated peripheral blood lymphocytes

Summary The 100 or so most intensely Coomassie blue-stained polypeptides from PHA-stimulated peripheral blood lymphocytes were analyzed by two-dimensional electrophoresis in combination with family and population studies. Besides polymorphic lymphocyte cytosol 64k polypeptide reported previously, genetic variants were frequently observed in three polypeptides with molecular weights of 100,000, 49,000, and 40,000. All of them occur in the cytosol. These variant polypeptides are charge variants, because they are separated in the isoelectric focusing dimension. It is indicated by family and population studies and cell distribution analysis that the polypeptide with a molecular weight of 100,000 shows a genetic polymorphism determined by two alleles at a new autosomal locus, as described in the following paper. Family and population studies also suggest that a genetic polymorphism defined by alleles at an autosomal locus is present in each of the polypeptides with molecular weights of 49,000 and 40,000. In contrast to the previous reports of the extremely restricted genetic variability of the 100 or so most abundant fibroblast polypeptides, the present data indicate that common genetic variants are present at least in four of the 100 or so most intensely Coomassie blue-stained lymphocyte polypeptides. The result also shows that careful side-by-side comparison of two-dimensional electrophoresis patterns among both parents and their children is an effective method to detect genetic variant polypeptides.     

Structural Analysis of an Extracellular Polysaccharide of Porodisculus pendulus

The aroL gene, encoding shikimate kinase of Brevibacterium lactofermentum, a coryneform glutamic acid-producing bacterium, was cloned. Recombinant plasmids containing the aroL gene caused elevated levels of shikimate kinase synthesis in B. lactofermentum. It was found that in addition to the aroL gene, the aroB and aroE genes, encoding dehydroquinate synthase and shikimate dehydrogenase, respectively, also existed on these recombinant plasmids, in complementation tests with various Escherichia coli and B. lactofermentum aromatic amino acid auxotrophs. The aroL, aroB and aroE genes of B. lactofermentum are located closely on the cloned DNA fragment, in that order. It was shown that at least these three aro genes form a cluster on the chromosome of B. lactofermentum.     

Production and Isolation of a New Antifungal Antibiotic,Prumycin and Taxonomic Studies of Streptomyces sp., Strain No. F-1028

A newly described species of Streptomyces (named Sm. kagawaensis ATCC No. 21811) isolated from soil was found to produce a new antifungal antibiotic, prumycin, which belongs to amino sugar group. Prumycin was isolated from the fermentation broth by ion-exchange adsorption and gel-filtration methods. This antibiotic inhibited specifically the growth of Sclerotinia sp. and Botrytis sp. on flower pot test with kidney bean leaves and also was effective on the field test with various plants.     

Phylogenetic analysis of bacteria preserved in a permafrost ice wedge for 25,000 years

Phylogenetic analysis of bacteria preserved within an ice wedge from the Fox permafrost tunnel was undertaken by cultivation and molecular techniques. The radiocarbon age of the ice wedge was determined. Our results suggest that the bacteria in the ice wedge adapted to the frozen conditions have survived for 25,000 years.     

SecY alterations that impair membrane protein folding and generate a membrane stress

We report on a class of Escherichia coli SecY mutants that impair membrane protein folding. The mutants also up-regulate the Cpx/sigma(E) stress response pathways. Similar stress induction was also observed in response to a YidC defect in membrane protein biogenesis but not in response to the signal recognition particle-targeting defect or in response to a simple reduction in the abundance of the translocon. Together with the previous contention that the Cpx system senses a protein abnormality not only at periplasmic and outer membrane locations but also at the plasma membrane, abnormal states of membrane proteins are postulated to be generated in these secY mutants. In support of this notion, in vitro translation, membrane integration, and folding of LacY reveal that mutant membrane vesicles allow the insertion of LacY but not subsequent folding into a normal conformation recognizable by conformation-specific antibodies. The results demonstrate that normal SecY function is required for the folding of membrane proteins after their insertion into the translocon.     

Cytostatic evaluations of nucleoside analogs related to unnatural base pairs for a genetic expansion system

The introduction of an unnatural base pair into DNA enables the expansion of genetic information. To apply unnatural base pairs to in vivo systems, we evaluated the cytostatic toxicity of several nucleoside analogs by an MTT assay. Several nucleoside analogs based on two types of unnatural base pairs were tested. One is a hydrogen-bonded base pair between 2-amino-6-(2-thienyl)purine (s) and pyridin-2-one (y), and the other is a hydrophobic base pair between 7-(2-thienyl)imidazo[4,5-b]pyridine (Ds) and pyrrole-2-carbaldehyde (Pa). Among the nucleoside analogs, the ribonucleoside of 6-(2-thienyl)purine possessed the highest cytostatic activity against CCRF-CEM and especially HT-1080, as well as the normal fibroblast cell line, WI-38. The other analogs, including its 2'-deoxy, 2-amino, and 1-deazapurine nucleoside derivatives, were less active against CCRF-CEM and HT-1080, and the toxicity of these nucleosides toward WI-38 was low. The nucleosides of y and Pa were inactive against CCRF-CEM, HT-1080, and WI-38. In addition, no cytostatic synergism was observed with the combination of the pairing nucleosides of s and y or Ds and Pa.