Immunological characterization of a 36 kDa Fe deficiency specific peptide in barley roots

In a previous paper we reported that an acidic 36 kDa peptide is the most strongly induced peptide among several peptides induced by Fe deficiency in barley roots. In this paper, polyclonal antibodies were raised against the 36 kDa peptide. This peptide appeared in the roots of all the graminaceous species tested (barley, rye, wheat, oat, maize, sorghum and rice) in response to Fe deficiency. More of the peptide was found in the roots of graminaceous species which secrete higher amounts of mugineic acids (MAs) under Fe deficient nutrition status. Induction of the 36 kDa peptide was first observed on the third day of Fe deficiency, rising to a maximum value on the seventh day. The trend has a positive correlation with secretion of MAs during Fe deficiency. Further, resupply of Fe resulted in a decrease in peptide production on the second day, reaching a control level on the seventh day. The rate of decrease in peptide production was observed to be slower than that of MA secretion. Other nutrient stresses such as B excess, B deficiency, Cu excess, Cu deficiency, Mn excess, Mn deficiency, Zn excess and Zn deficiency induced far less of the peptide. The specific expression of the 36 kDa peptide in roots of graminaceous species under Fe deficiency suggested the positive association of the peptide with a specific Fe deficiency tolerance mechanism in graminaceous plants.     

Analysis of the NH2-Terminal 83rd Amino Acid of Escherichia coli GyrA in Quinolone-Resistance

Artificial mutations of Gyrase A protein (GyrA) in Escherichia coli by site-directed mutagenesis were generated to analyze quinolone-resistant mechanisms. By genetic analysis of gyrA genes in a gyrA temperature sensitive (Ts) background, exchange of Ser at the NH₂-terminal 83rd position of GyrA to Trp, Leu, Phe, Tyr, Ala, Val, and Ile caused bacterial resistance to the quinolones, while exchange to Gly, Asn, Lys, Arg and Asp did not confer resistance. These results indicate that it is the most important for the 83rd amino acid residue to be hydrophobic in expressing the phenotype of resistance to the quinolones. These findings also suggest that the hydroxyl group of Ser would not play a major role in the quinolone-gyrase interaction and Ser83 would not interact directly with other amino acid residues.     

Novel mutation at the initiation codon in the Norrie disease gene in two Japanese families

We have identified a new mutation of Norrie disease (ND) gene in two Japanese males from unrelated families; they showed typical ocular features of ND but no mental retardation or hearing impairment. A mutation was found in both patients at the initation codon of exon 2 of the ND gene (ATG to GTG), with otherwise normal nucleotide sequences. Their mothers had the normal and mutant types of the gene, which was expected for heterozygotes of the disease. The mutation of the initiation codon would cause the failure of ND gene expression or a defect in translation thereby truncating the amino terminus of ND protein. In view of the rarity and marked heterogeneity of mutations in the ND gene, the present apparently unrelated Japanese families who have lived in the same area for over two centuries presumably share the origin of the mutation.     

Beta-2 microglobulin types in mice of wild origin

To determine the distribution of beta-2 microglobulin (B2m) alleles in wild mice we have typed mice derived from natural populations in Europe, North Africa, South America, and East Asia. Mus musculus domesticus mice from Germany, France, Italy, and Peru were all B2m ^a as were most from the United Kingdom. M.m. musculus mice from Denmark and Czechoslovakia, several stocks of M.m. molossinus from Japan, and M.m. castaneus from China, Thailand, and the Philippines were of B2m ^b type. This is consistent with the notion that C57BL/6 may have obtained some of its genes, including B2m, from Eastern mice. A BgII restriction site characteristic of B2m ^b was also found in mice from Czechoslovakia and Japan, confirming that B2m ^b is a naturally occurring allele of B2m. A new type of ₂m ( ₂m^w1) was found in four stocks of M. spretus from Portugal, Spain, and Morocco. This molecule differs in apparent size and charge from the a and b types. ₂m^w2 was found together with ₂ ma in one stock of M.m. domesticus (brevirostris) from Morocco. ₂m^w3 and ₂m^w4 were found in a few M. m. bactrianus from Pakistan. In all cases tested, these new ₂m molecules associate with class I histocompatibility antigens.Abbreviations used in this paper ₂m beta-2 microglobulin - B2m gene for beta-2 microglobulin - IEF isoelectric focusing - SDS-PAGE polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate - MHC major histocompatibility complex - T. E. Tris-EDTA buffer     

Presence of adrenocorticotropin-potentiating factors in porcine thyroid glands

An extract of porcine thyroid gland in 0.1 N acetic acid exerted dose-dependent potentiation of ACTH-induced corticosterone production in isolated rat adrenal cells. The extract by itself manifested no steroidogenic activity. Upon gel-filtration of the extract, potentiating activities were demonstrated in three main peaks with molecular weights of about 10,000, 5,000 and 2,000. These findings indicate the presence of heterogeneous forms of ACTH-potentiating factors in the thyroid. Significant enhancement of ACTH-induced steroidogenesis was readily apparent with three gel-filtration fractions at a lower concentration of ACTH (4.75 pM). At this concentration, dose-dependent potentiation was observed with these three fractions. Enhanced corticosterone production responses by cells preincubated with the thyroid extract were observed and the results indicated the existence of potentiating mechanisms other than inhibition of ACTH proteolysis. The lack of T4, T3 and thyroglobulin in this activity suggests that the activity resides in other constituents of the thyroid.     

Unstable resistance of G mouse fibroblasts to ecotropic murine leukemia virus infection.

G mouse cells were resistant to N- and NB-tropic Friend leukemia viruses and to B-tropic WN 1802B. Though the cells were resistant to focus formation by the Moloney isolate of murine sarcoma virus, they were relatively sensitive to helper component murine leukemia virus. To amphotropic murine leukemia virus and to focus formation by amphotropic murine sarcoma virus, G mouse cells were fully permissive. When the cell lines were established starting from the individual embryos, most cell lines were not resistant to the murine leukemia viruses. Only one resistant line was established. Cloning of this cell line indicated that the resistant cells constantly segregated sensitive cells during the culture; i.e., the G mouse cell cultures were probably always mixtures of sensitive and resistant cells. Among the sensitive cell clones, some were devoid of Fv-1 restriction. Such dually permissive cells, and also feral mouse-derived SC-1 cells, retained glucose-6-phosphate dehydrogenase-1 and apparently normal number 4 chromosomes. The loss of Fv-1 restriction in these mouse cells was not brought about by any gross structural changes in the vicinity of Fv-1 on number 4 chromosomes.     

An increased level of sperm abnormalities in mice with a partial deletion of the Y chromosome

Two congenic lines of mice, one with a partial deletion of the Y chromosome, differ in the percentage of spermatozoa with abnormal heads: B10.BR/SgSn males give 22.6% and B10.BR-Ydel/Ms males give 64.2% abnormal sperm. The F1s resulting from crosses of B10.BR/SgSn males with females of five common inbred strains exhibited significantly lower levels of abnormal sperm than the parental strains, as opposed to F1 hybrids sired by B10.BR-Ydel/Ms mutant males, where very high levels of abnormal spermatozoa were found. About 30% of abnormal spermatozoa, produced by males with deletion on the Y chromosome, were characterized by a flat acrosomal cap. This class of abnormality was never observed in non-mutant males, suggesting a mutant-specific defect. These results demonstrate the important role of the Y chromosome in spermatogenesis.     

Purification and properties of a lytic enzyme from the cell wall of Chlorella ellipsoidea C-87

Cell wall lytic activity was detected in the culture medium and cell wall of 1AM Chlorella ellipsoidea C-87. The enzymes of both fractions had their highest activity at pH 5. The lytic activity bound to the cell wall consisted of a polysaccharide releasing enzyme, an exo-type enzyme releasing disaccharide, and glucosidase; but only the polysaccharide releasing enzyme was solubilized by lithium chloride. A polysaccharide releasing enzyme with a molecular weight around 40 kDa was isolated from the culture medium. Hemicellulose is degraded by the polysaccharide releasing enzyme, and the rigid wall by the exo-type enzyme.