HLA-DQ system and insulin-dependent diabetes mellitus in Japanese: does it contribute to the development of IDDM as it does in Caucasians?

Fifty-six unrelated Japanese patients with insulin-dependent diabetes mellitus (IDDM) were HLA-typed, and restriction fragment length polymorphism (RFLP) analysis was performed after enzyme digestion with Bam HI and Taq I by using both DR and DQ probes. As previously reported, increased frequencies of Bw54, Cw1, DR4, and DRw53, which are in strong linkage disequilibrium in the Japanese population and make the characteristic Japanese haplotype, were confirmed. DQw4, a new allele of the DQ system recognized by the monoclonal antibody HU-46 and in linkage disequilibrium with this haplotype, presented the highest IDDM association. The RFLP analysis also showed the strongest correlation to IDDM when the DQ probe was applied. These results indicate that HLA-DQ might play the most important role in the development of IDDM in Japanese as well as in Caucasians. The correlation of DQ amino acid sequences strongly associated with IDDM in Japanese are discussed in this study, and contrasting results were found when such sequences were compared with those of Caucasians.Abbreviations used in this paper IDDM insulin-dependent diabetes mellitus - RFLP restriction fragment length polymorphism - Asp aspartic acid - Asp-57 aspartic acid at the 57th residue of the DQ chain - non-Asp-57 nonaspartic acid at the 57th residue of the DQ chain - R.R. relative risk of Woolf and Haldane     

Immobilization of enzymes on alumina by means of pyridoxal 5′-phosphate

A number of proteases have been immobilized on alumina in a two-step procedure: the first step converted them into semisynthetic phosphoproteins which, in the second step, spontaneously bonded to alumina through their phosphate function. The immobilized enzymes thus obtained showed the physical properties typical of the inorganic carrier and a high activity on low molecular weight substrates.     

Isolation and biochemical characterization of Streptomyces clavuligerus mutants in the biosynthesis of clavulanic acid and cephamycin C

Summary Seven mutants of Streptomyces clavuligerus blocked in the biosynthesis of clavulanic acid, cephamycin C, or both antibiotics, have been isolated and characterized. Mutants nca1 and nca2 were unable to synthesize clavulanic acid but produced cephamycin C. Mutants nce1 and nce2 were completely blocked in cephamycin C production but formed clavulanic acid. A third group (mutants ncc1, ncc4 and ncc5) failed to produce both antibiotics. Arginase activity (forming ornithine) was very low in mutants ncc1 and ncc5. All the mutants blocked in clavulanic acid biosynthesis showed a normal ornithine--aminotransferase activity. Mutant ncc1, blocked in cephamycin biosynthesis, lacked completely lysine--aminotransferase (forming -aminoadipic acid) and isopenicillin N synthase. Two other mutants (nce2 and nce5) lacked isopenicillin N synthase. There was a good correlation between the isopenicillin N synthase and the lysine--aminotransferase activities of the nca mutants and the ability of those strains to produce cephamycin C. The condensing enzyme involved in the formation of the clavulanic acid nucleus appears to be different from the isopenicillin N synthase.Dedicated to Professor H.-J. Rehm on the occasion of his 60th birthday     

Centrifugation of 2-cell mouse ova: cytoplasm stratification and recovery

Summary Two-cell mouse ova, which were centrifuged for l h at 70 000–90 000xg, showed a precise stratification of the cytoplasm and an elongation of the nucleus. The ova were fixed at different times and observed by light and electron microscopy using cytochemical methods and detergent extractions. Within 40 min after centrifugation the normal-looking morphology was recovered except for the persisting lipid caps at the centripetal poles of the blastomeres. Cleavage, compaction and blastulation were not prevented by centrifugation. Treatments with colcemid or cytochalasin D delayed but did not impair recovery. These results suggest that a resilient cytoskeletal structure may be involved in this kind of embryonic regulation.     

Changes in invertase activities precede ovary growth induced by gibberellic acid in

Developing pods of pea ( Pisum sativum L. cv. Alaska no 7) were used to study the enzymes of sucrose metabolism. Acid and neutral invertase (EC 3.2.1.26). sucrose synthase (SS, EC 2.4.1.13) and sucrose phosphate synthase (SPS, EC 2.4.1.14) have been localized in the soluble fraction. Acid invertase activity was also present in the insoluble fraction and in pea ovary apoplast. In pea pods, sucrose breakdown was dominated by the invertase pathway. SS specific activity only increased at late stages of parthenocarpic pod development, while SPS did so in pods obtained by pollination. Changes in time course of invertase activities have been correlated with the growth rate of fruits induced to develop either by fertilization or by exogenous application of giberellic acid (GA), 2,4-dichloro-phenoxy acetic acid (2,4-D) or 6-benzylaminopurine (6-BAP). The soluble neutral activities might be associated with pod elongation, while the acid ones were rather related to assimilate import by the induced fruits. Application of gibberellic acid to non-pollinated ovaries significantly enhanced the soluble neutral invertase activity before any ovary outgrowth was detected (up to 2 h after treatment). Within the same period of time. GA-treated ovaries showed a decrease in the acid invertase activity of the soluble fraction and an increase of the acid invertase activity in the apopiast. preceding in time the increment of the acid invertase activity associated with the insoluble fraction. Our results suggest that the early GA response may be mediated through a promotion of processes of protein secretion.     

Nuclear genome characterization of the carrageenophyteAgardhiella subulata (Rhodophyta)

DNA reassociation kinetics were used to determine nuclear genome organization and complexity inAgardhiella subulata (Gigartinales, Rhodophyta). Results indicate the presence of three second-order components corresponding to fast (22%), intermediate (68%) and slow (10%) fractions. Thus, the genome consists of 90% repetitive sequences. Microspectrophotoometry with the DNA-localizing fluorochrome DAPI was used to confirm ploidy level differences in the gametophytic and tetrasporophytic phases. Results indicate that meiosis occurs during tetrasporogenesis. Comparison of mean nuclear DNA (I_f) values to chicken erythrocytes (RBC) resulted in an estimate of 0.9 pg/2C genome forAgardhiella. Karyological studies using aceto-orcein revealed a chromosome complement of 2N = 44 in carposporangia and the presence of 22 bivalents during diakinesis of tetraspore mother cells.     

Pigment patterns in mutants affecting the biosynthesis of pteridines and xanthommatin in Drosophila melanogaster

Eye-color mutants of Drosophila melanogaster have been analyzed for their pigment content and related metabolites. Xanthommatin and dihydroxanthommatin (pigments causing brown eye color) were measured after selective extraction in acidified butanol. Pteridines (pigments causing red eye color) were quantitated after separation of 28 spots by thin-layer chromatography, most of which are pteridines and a few of which are fluorescent metabolites from the xanthommatin pathway. Pigment patterns have been studied in 45 loci. The pteridine pathway ramifies into two double branches giving rise to isoxanthopterin, drosopterins, and biopterin as final products. The regulatory relationship among the branches and the metabolic blockage of the mutants are discussed. The Hn locus is proposed to regulate pteridine synthesis in a step between pyruvoyltetrahydropterin and dihydropterin. The results also indicate that the synthesis and accumulation of xanthommatin in the eyes might be related to the synthesis of pteridines.Support for this work was provided to J.F. in part by a grant from the Ministerio de Universidades e Investigación (Spain) and to F.J.S. by a grant from the Ministerio de Educación y Ciencia (Spain).     

Zur Mauser spanischer Weiden- und Haussperlinge (Passer hispaniolensis unddomesticus)

Zusammenfassung Die Mauserperiode westspanischer Weidensperlinge(Passer hispaniolensis) und Haussperlinge(P. domesticus) reicht von Ende Juli bis Ende September/Anfang Oktober. Beim Weidensperling endet der Federwechsel im Durchschnitt etwa fünf Tage früher als beim Haussperling. Es gibt keine Geschlechtsunterschiede in der Chronologie der Mauser beim Weidensperling. Ad. beider Arten mausern schneller und synchronisierter als juv., die ihr Gefieder um so rascher erneuern, je später sie mit der Mauser begonnen haben. Die Handschwingenmauser dauert etwa 66 Tage beim Weidensperling und 69 Tage beim Haussperling. Beide Arten brauchen ca. 3 weitere Tage für die Verhornung der 5. und 6. Armschwingen. Die ad. beider Arten und die juv. Weidensperlinge beginnen die Mauser im Durchschnitt am selben Tag (24. Juli), die juv. Haussperlinge später (29. Juli). Der Mauserverlauf und die Beziehungen zwischen den verschiedenen Federreihen sind bei beiden Arten identisch. Die Synchronisation der Mauser ist beim Weidensperling höher. Brut und Mauserperiode überschneiden sich beim Haussperling; beim Weidensperling, bei dem noch kurze Wanderungen gleich nach der Fortpflanzungsperiode und vor der Mauser erfolgen, nicht. Das frühere und höher synchronisierte Mauserende beim Weidensperling scheint eine Anpassung an die stärkere Zugtendenz zu sein.

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On the moult of Spanish Sparrows(Passer hispaniolensis) and House Sparrows(Passer domesticus) in Iberia

Summary The moulting period of Spanish sparrows(Passer hispaniolensis) and House Sparrows(Passer domesticus) in Western Spain extends from late July to late September/early October. House Sparrows finish moulting on average some five days later than Spanish Sparrows. There are no sexual differences in the moulting chronology of adult Spanish Sparrows. Ad. of both species moult faster and better synchronized. The speed of moulting is also higher in later moulting juveniles. The estimated durations of wing feather replacement were 66 days for the Spanish Sparrow and 69 days for the House Sparrow. Some three more days are needed to complete the growth of the 5th and 6th secondary remiges in both species. Adults of both species and juvenile Spanish Sparrows start moulting on average on the same date: 24th July; juvenile House Sparrows start moulting on 29th July. The sequence of moult and the relations between different feather tracts are identical in both species. The synchronization of the moult is higher in the Spanish Sparrow. Breeding and moulting seasons slightly overlap in the House Sparrow, but not in the Spanish Sparrow. In this species the time lapse between both periods allows the birds to wander to suitable areas, where they moult. The earlier ending and higher synchronization of the moult in the Spanish Sparrow is related to its higher migratory tendency.