Seasonal changes of the ultrastructure of the pars tuberalis of the hypophysis of Rana temporaria

Summary In the pars tuberalis of the hypophysis of Rana temporaria, which shows the ultrastructural characteristics of a polypeptide hormone secreting endocrine gland, seasonal changes of the ultrastructure are described. In accordance with the literature, these seasonal changes of ultrastructure are interpreted as the morphological expression of seasonal changes of endocrine activity of the pars tuberalis.     

Immunocytochemical localization of somatostatin in the brain of the lizard, Ctenosauria pectinata

The brain of the lizard, Ctenosauria pectinata, was studied light microscopically using an immunocytochemical staining method that is specific for neurohypophysial hormones and somatostatin. It was shown that the telencephalon and particularly the diencephalon contain somatostatin-producing perikarya, while somatostatinergic fibers occur in the entire brain. Similar to the situation in other vertebrates, somatostatin neurons in Ctenosauria pectinata form a population distinct from the neurohypophysial hormone-producing neurons. The small-sized somatostatin neurons were found in the cortex and the diencephalon: (1) ventral from, and partially overlapping with, the classical neurosecretory paraventricular nucleus; and (2) in the region of the infundibular (tuberal) nucleus. Somatostatin fibers were found among the classical neurosecretory fibers of the supraoptico-paraventricular system (tract, median eminence, neural lobe), near to and within the epiphysis, in the septum, in the vicinity of the tectum opticum and the cerebellum, and in the tegmentum.     

The effect of the H2 partial pressure on the metabolite pattern ofLactobacillus casei,Escherichia coli andClostridium butyricum

Summary The metabolite pattern of batch cultures ofLactobacillus casei LMG 6400,Clostridium butyricum LMG 1213t1 andEscherichia coli LMG 2093 was effected only for the latter organism when the H₂ partial pressure was below 1 atmosphere: high hydrogen partial pressures increased the formate formation, low pressures gave rise to increased acetate production and higher cell yields.     

New enrichment method for isolation of pathogenic Yersinia enterocolitica serogroup O:3 from pork

A new enrichment medium for the recovery of pathogenic Yersinia enterocolitica serogroup O:3 from naturally infected meat products based on three selective agents, Irgasan, ticarcillin, and potassium chlorate (ITC), was compared with several other one- or two-step enrichments. Y. enterocolitica serogroup O:3 was recovered from 96.5% of 29 pork tongues, 24% of 50 ground pork samples, 16% of 25 masseter muscle samples, and 61% of tonsils. ITC was by far the most sensitive method for the recovery of Y. enterocolitica O:3, especially from ground meat and masseter muscles, while cold and two-step enrichments yielded better results for nonpathogenic strains. Plating of ITC enrichments onto SS-deoxycholate-calcium agar gave overall better results than plating onto cefsulodin-Irgasan-novobiocin agar for serogroup O:3.     

Determination of the spectrum of beta-thalassemia genes in Spain by use of dot-blot analysis of amplified beta-globin DNA.

We have delineated the molecular lesions causing beta-thalassemia in Spain, a country that has witnessed the passage of different Mediterranean populations over the centuries, in order to evaluate the extent of heterogeneity of these mutations and to make possible simplified prenatal diagnosis of the disorder in that country. The use of the polymerase chain-reaction (PCR) technique to preferentially amplify beta-globin DNA sequences that contain the most frequent beta-thalassemia mutations in Mediterraneans enabled us to rapidly analyze 58 beta-thalassemia alleles in a dot-blot format either by hybridization with allele-specific radiolabeled oligonucleotide probes or by direct sequence analysis of the amplification product. The Spanish population carries seven different beta-thalassemia mutations; the nonsense codon 39 is predominant (64%), whereas the IVS1 position 110 mutation, the most common cause of beta-thalassemia in the eastern part of the Mediterranean basin, is underrepresented (8.5%). The IVS1 mutation at position 6 accounts for 15% of the defects and leads to a more severe form of beta+-thalassemia than originally described in most of the patients we studied. In this study, we demonstrate further the usefulness of the dot-blot hybridization of PCR-amplified genomic DNA in both rapid population surveys and prenatal diagnosis of beta-thalassemia.     

Assignment of human uroporphyrinogen decarboxylase (URO-D) to the p34 band of chromosome 1

Summary A cDNA probe corresponding to mRNA encoding human uroporphyrinogen decarboxylase (URO-D) was used to determine the chromosomal localization of the URO-D gene in the human genome. In agreement with previous studies, we have found that the locus for URO-D is located on chromosome 1 in hybrid cell mapping panels. The use of in sity hybridization allowed us to map the URO-D locus to band 1p34.Part of this work was presented as an abstract entitled Localization of the uroporphyrinogen decarboxylase gene to 1p34 band, by in situ hybridization, by M. G. Mattei, A. Dubart, D. Beaupain, M. Goossens, and J. F. Mattei, for a poster presentation at the 8th International Conference on Human Gene Mapping, Helsinki, August 4–10, 1985     

Mutations in the catalytic domain of human coagulation factor IX: rapid characterization by direct genomic sequencing of DNA fragments displaying an altered melting behavior

Deficiency in coagulation factor IX, a plasma glycoprotein constituent of the clotting cascade, results in hemophilia B, an inherited recessive X-linked bleeding disorder. Some affected individuals, referred to as antigen positive or CRM+, express an inactive factor IX gene product at normal levels and are expected to have natural mutations altering domains of the molecule that are critical for its correct function. The serine protease catalytic domain of activated factor IX, encoded by exons VII and VIII of the gene, is a possible target for such mutations. We designed a strategy allowing rapid analysis of this region through enzymatic amplification of genomic DNA, analysis of the amplification products by denaturing gradient gel electrophoresis, and direct sequencing of the fragments displaying an altered melting behavior. This procedure permitted us to characterize two previously undescribed mutations. Factor IX Angers is a G-to-A substitution generating an Arg in place of a Gly at amino acid 396 of the mature factor IX protein. Factor IX Bordeaux is an A-to-T substitution introducing a nonsense codon in place of the normal codon for Lys at position 411. Moreover, the already described factor IX Vancouver defect was found in three apparently independent families. These results provide further insight into the molecular heterogeneity of hemophilia B. In addition, we demonstrate the usefulness of this rapid screening procedure, which has broad applications in human genetics and can be used as an alternative to RFLP analysis in carrier detection or prenatal diagnosis studies.