No evidence for an autoregulatory mechanism for the proestrous afternoon surge of prolactin secretion in rats

The temporal effects of intracerebroventricular (icv) infusion of prolactin (PRL) on endogenous PRL secretion was investigated in intact, freely moving, cycling rats. An icv infusion of 10 ng or 100 ng rat-PRL/min from 13.00 to 17.00 h during the proestrous afternoon did not affect endogenous PRL secretion; infusion from 09.00 to 13.00 h showed a tendency to delay the time of onset of the PRL proestrous afternoon surge. The results do not indicate the involvement of an autoregulatory mechanism in the expression or the termination of the proestrous afternoon surge of PRL secretion.     

Specific truncations of an acetolactate synthase gene from Brassica napus efficiently complement ilvB/ilvG mutants of Salmonella typhimurium

Summary The expression of an acetolactate synthase (ALS) gene isolated from the cruciferous plant Brassica napus was investigated in Salmonella typhimurium. Using an expression plasmid containing the highly active trc (trp-lac) promoter, several plant ALS constructs were made containing successive in-frame truncations from the 5 end of the coding region. Functional complementation by these plant ALS constructs of a S. typhimurium mutant devoid of ALS enzymic activity was assayed on minimal medium. Truncations which eliminated a large portion of the transit peptide coding sequence proved to act as efficient ALS genes in the bacterial host. Truncations close to the putative processing site of the plant protein were inactive in the complementation test. A full length copy of the gene, including the entire transit peptide coding region, was also inactive. The efficiency of the complementation, estimated by comparison to the growth rate of wild-type S. typhimurium, was found to correlate with levels of ALS activity in the transformed bacteria. Specific mutations, known to produce herbicide resistance in plants, were introduced into the truncated ALS coding sequence by site-directed mutagenesis. When expressed in bacteria these constructs conferred a herbicide resistance phenotype on the host. The potential of this system for mutagenesis and enzymological studies of plant proteins is discussed.     

Isolation of taste buds from the foliate papillae of the rabbit

Summary A method to isolate taste buds from the foliate papillae of the rabbit tongue is described. The method comprises (a) separation of the epidermis from the dermal layer after treatment with dilute acetic acid, and (b) mechanical removal of the taste buds from the epithelium with the use of a surgical needle. The procedure yields taste buds that are morphologically well preserved, and in quantities sufficient to enable a detailed biochemical characterization. Preliminary tests have shown the taste buds to have biochemical properties clearly distinct from those of the adjacent epithelium. The method may provide a basis for studying the molecular mechanism of taste perception in greater detail.On leave of absence from the Medical Research Centre, Polish Academy of Sciences, Warsaw, Poland.     

Location of taste buds in intact taste papillae by a selective staining method

Summary Taste buds were found to stain strongly and selectively in intact papillae with highly acidic dyes such as ponceau S. In intact tongues the taste buds in the fungiform, circumvallate and foliate papillae of the cynomolgus monkey and in the fungiform papillae of the rat as well as the taste discs in the fungiform papillae of the frog could be visualized. This method enables a rapid location and counting of taste buds in taste papillae without preparing histological sections. In cynomolgus tongue material fixed in formalin, the dyes penetrate into the buds. In fresh tongues only the taste pore region of the buds stains, which suggests that in vivo taste buds are impenetrable underneath the pore.     

The ethology of inter-individual differences

In recent times psychologists have shown a growing interest in ethological methods of data collection. At the same time ethologists are showing a growing interest in the methods of data processing as developed in personality psychology. These methods of data processing appear to be most useful to ethological research when investigating differences between individuals. Using factor analysis of aggressive behaviour as an example, it is argued that an ethological approach which focusses on individual differences may add substantial information to the models derived from a (classical) ethological approach which only concerns general pictures of species. The advantages of the proposed research procedures are discussed, especially in relation to behavioural genetic and ontogenetic research.Without the help and assistance of staff members of the departments of ethology and personality psychology of Groningen University this text would never have reached its present form. The suggestions of Ference Bodnár, Ciska Feekes, No Molenaar, Nance Vodegel and Annemarie van der Molen are gratefully acknowledged. Translation from Dutch into English was taken care of by Margi and Talib Rothengatter. The drawings were prepared by Agnes de Graaf.     

Morphometric Analysis of Normal, Mutant, and Transgenic CNS: Correlation of Myelin Basic Protein Expression to Myelinogenesis

The neurological mutant mice shiverer (shi) and myelin deficient (shimld) lack a functional gene for the myelin basic proteins (MBP), have virtually no myelin in their CNS, shiver, seize, and die early. Mutant mice homozygous for an MBP transgene have MBP mRNA and MBP in net amounts approximately 25% of normal, have compact myelin, do not shiver or seize, and live normal life spans. We bred mice with various combinations of the normal, transgenic, shi, and shimld genes to produce mice that expressed MBP mRNA at levels of 0, 5, 12.5, 17.5, 50, 62.5, and 100% of normal. The CNS of these mice were analyzed for MBP content, tissue localization of MBP, degree of myelination, axon size, and myelin thickness. MBP protein content correlated with predicted MBP gene expression. Immunocytochemical staining localized MBP to white matter in normal and transgenic shi mice with an intensity of staining comparable to the degree of MBP gene expression. An increase in the percentage of myelinated axons and the thickness of myelin correlated with increased gene expression up to 50% of normal. The percentage of myelinated axons and myelin thickness remained constant at expression levels greater than 50%. The presence of axons loosely wrapped with oligodendrocytic membrane in mice expressing lower amounts of MBP mRNA and protein suggested that the oligodendroglia produced sufficient MBP to elicit axon wrapping but not enough to form compact myelin. Mean axon circumference of myelinated axons was greater than axon circumference of unmyelinated axons at each level of gene expression, further evidence that oligodendroglial cells preferentially myelinate axons of larger caliber.(ABSTRACT TRUNCATED AT 250 WORDS)     

The Basal Nodosaurid Ankylosaur Europelta carbonensis n. gen., n. sp. from the Lower Cretaceous (Lower Albian) Escucha Formation of Northeastern Spain

Nodosaurids are poorly known from the Lower Cretaceous of Europe. Two associated ankylosaur skeletons excavated from the lower Albian carbonaceous member of the Escucha Formation near Ariño in northeastern Teruel, Spain reveal nearly all the diagnostic recognized character that define nodosaurid ankylosaurs. These new specimens comprise a new genus and species of nodosaurid ankylosaur and represent the single most complete taxon of ankylosaur from the Cretaceous of Europe. These two specimens were examined and compared to all other known ankylosaurs. Comparisons of these specimens document that Europelta carbonensis n. gen., n. sp. is a nodosaur and is the sister taxon to the Late Cretaceous nodosaurids Anoplosaurus, Hungarosaurus, and Struthiosaurus, defining a monophyletic clade of European nodosaurids– the Struthiosaurinae.     

IGFs and IGF-Binding Proteins in the Synovial Fluid of Patients with Rheumatoid Arthritis and Osteoarthritis

International Journal of Peptide Research and Therapeutics - The progressive damage of human articular cartilage is associated with loss of integrity of its extracellular matrix components. Their...