The Question of a Vomer in Brachiopterygian Fish

Abstract The term vomer was coined over four centuries ago to denote one of the 23 bones normally comprising an adult human skull. As time went on more and more craniates were designated vomerate. To date, however, the issue as to whether brachiopterygian fish are or are not vomerate has remained unresolved. Those who consider these fish to be vomerate have suggested at least three different palatal bones as the homologue of the human vomer. Examination of embryological material of Polypterus senegalus shows that this brachiopterygian actually develops a vomer which eventually becomes united indistinguishably with the anterior part of the parasphenoid. The vomer is suggested to have arisen through the fusion of dental plates belonging to a supplementary set of buccopharyngeal denticulate bones. The other subethmoidal bones of the brachiopterygian palate seem likely to be derivatives of the tooth plates which originally were applied to the first two pairs of infrapharyngeals. When these endoskeletal elements were put to use for encapsulation of the organs of smell early in craniate phylogeny, some of the tooth plates that covered their inner surfaces fused to provide anterior palatal bones. Identified at one time or another as vomers, these bones are here termed glochinals and dacnils.     

Human lymphoblastoid cell lines secreting antibodies with restricted HLA specificity

Peripheral B lymphocytes obtained from three healthy individuals who had been immunized against peripheral blood lymphocytes from appropriate HLA-incompatible donors were transformed by the use of Epstein-Barr virus. The transformed blastoid B cells were repeatedly subcultured by means of cluster picking, and the HLA antibody-producing cultures were identified by testing the culture supernatants by means of the cytotoxicity assay, using the corresponding donor cells. Thus far, four cell lines that secrete cytotoxic HLA antibodies (MP1, 3, 4, and 5) have been established. Specific immunoabsorption experiments revealed that the antibody activity is carried by lambda-type IgM for MP1, by kappa-type IgM for MP3 and MP5, and by both for MP4. Specificity analysis of a panel of HLA-pretyped cells indicated that MP1 detects DQw2, whereas MP5 recognizes B7. The specificity of MP3 was similar to a DQ specificity termed DC5 (probably equivalent to TA10) but not the same. In the case of MP4, both of the lambda-type and kappa-type antibodies appeared to be directed toward new HLA class 11 determinants.Abbreviations used in this paper HLA human major histocompatibility - EBV Epstein-Barr virus - B-LCL Blymphoblastoid cell line - NA not absorbed - PBS phosphate-buffered saline - SPA Sepharose protein A - NRS normal rabbit serum     

Inhibitors of the cleavage of aclacinomycins

Summary The reductive cleavage of the aclacinomycins A (I), Y (II), and B (III) by intact mycelia or subcellular fractions of the producer strain S. spec. AM 33352/F43 is suppressed in the presence of uncouplers, complex-forming agents, detergents, and some metal anions such as chromate. Increased concentration of the latter in complete cultures caused rearrangement of I to III.     

Xylose catabolism by a mutant ofStreptomyces chrysomallus altered in the regulation of D-glucose isomerase

Summary A mutant ofS. chrysomallus with a D-glucose isomerase inducible by D-glucose or its catabolites was characterized. In contrast to the wild-type strain it showed a decreased catabolite repression by D-glucose of D-xylose consumption and a constitutive pentose phosphate pathway as well. A hypothesis concerning altered induction pattern of its D-glucose isomerase is discussed.     

Paternal inheritance of chloroplast DNA in Larix

Restriction enzyme analysis was used to determine the inheritance of chloroplast DNA in conifers. The plant material studied included five individual trees of European larch (Larix decidua Mill.) and Japanese larch (Larix leptolepis Sieb. & Zucc.) and six hybrids from controlled crosses between these species. The chloroplast DNA fragment patterns generated by Bam-HI and Bcl-I were species-specific. Paternal inheritance of chloroplast DNA patterns was found in most Larix crosses. One hybrid showed maternal chloroplast DNA patterns. In addition, two other hybrids had mixed Bam-HI patterns suggesting recombination between maternal and paternal chloroplast DNA. The mechanisms favoring paternal inheritance in conifers are not known. Paternal inheritance of chloroplast DNA is suggested it to be a general phenomenon in conifers.     

Plant regeneration from protoplasts of the monocotyledonous Haworthia magnifica v. Poelln.

Calli were initiated from flower buds, gynoecia and inflorescence segments of Haworthia magnifica v. Poelln. and subcultured on solid medium. Two liquid culture steps were necessary to prepare the calli for the isolation of protoplasts capable of sustained cell divisions. Plants were regenerated from protoplast-derived calli. The influence of both the osmolality of the culture media and exudates on the viability of protoplasts and protoplast-derived cell colonies is briefly discussed.     

Semicontinuous penicillin production by two Penicillium chrysogenum strains immobilized in calcium alginate beads

Summary The growth rates of immobilized Penicillium chrysogenum strains are important in their application to semicontinuous penicillin production. Immobilized P. chrysogenum strains produced about 10–15% less biomass but about 1–2 times more penicillin than free suspended mycelia.In a chemically defined medium an industrial P. chrysogenum strain, S₁, produced about 10–12 times more penicillin than strain ATCC 12690. In a complex medium the immobilized P. chrysogenum S₁ produced about 12% penicillin more than in shaken cultures. In bubble column fermentations, penicillin production was 163% higher in the complex medium than in the chemically defined medium.     

Effects of cultural conditions on the production of phenylalanine from a plasmid-harboring E. coli strain

Summary Phenylalanine production from E. coli KA 197/pJN6 (plasmid harboring genes for aro F, phe A^FBR, Amp^R and Tc^R) was studied under varying nutritional conditions in batch and continuous cultures. In batch culture experiments where growth was deliberately interrupted by limiting concentrations of sulphate and phosphate the phenylalanine production continued from the non-growing cells. However, the depletion of phosphate resulted in an immediate cessation of phenylalanine production but thereafter a low specific rate of phenylalanine formation resumed, while the decrease in specific rate of product formation was less after sulphate depletion. In the chemostat experiments, however, phosphate limitation was the only case where the specific rate of phenylalanine formation remained constant, while at the corresponding time in sulphate and glucose limited chemostats it was declining respectively had ceased.