Ontogeny of hormone-secreting cells of the rat pituitary gland: An immunocytochemical study on dissociated cells

Summary An immunocytochemical study was undertaken in foetal, prepubertal and mature rats to determine the time of differentiation of various types of adenohypophyseal cells during development. Freshly dissociated pituitary cells from foetal (18–21 days postconception), neonatal (from birth up to 30 days) and adult rats (more than 8 weeks) were characterized using immunocytochemical methods. All types of hormone-producing cells were present at day 18 postconception, although only 20% of the cells were immunolabelled. Adrenocorticotropin (ACTH)-secreting cells accounted for the highest number of hormone-positive cells. Growth hormone-secreting cells increased remarkably from day 18 postconception onwards. Prolactin-secreting cells were not seen in the foetal adenohypophysis and did not start to increase until 10 days after birth, whereas by that time the number of ACTH, thyrotropin, follicle-stimulating and luteinizing hormone-secreting cells had stopped increasing. By day 30 after birth, 80–95% of the cells were immunoreactive.     

Plant regeneration by organogenesis in Vitis rootstock species

A procedure for the regeneration of Vitis rootstocks plantlets by organogenesis from foliar tissues is described. Leaves from mature plants grown in growth chambers or from plantlets grown in tubes were wounded with a scalpel and cultured on a modified Murashige and Skoog liquid medium containing different concentrations of benzyl-aminopurine. The presence of benzyl-aminopurine is required for shoot formation. The age of the source explant, the composition of the culture medium and the culture temperature are important parameters of the regeneration process.Abbreviations BA 6-benzyl-aminopurine - MS Murashige and Skoog medium - MM modified Murashige and Skoog medium     

Phenetic relationships inClerodendrum (Verbenaceae) and some phylogenetic considerations

Cluster analyses by different methods and a minimum spanning tree were used to study phenetic relationships in the genusChlerodendrum. 129 species were scored for 52 morphological characters corresponding to 119 character states. The phenetic results suggest a classification into 7 distinct groups, which may be grouped into two subgenera. This classification is supported by the iridoid distribution as well as by some phylogenetic considerations.     

Chemical signalling and monopolization of nectar resources by territorial Pachymelus limbatus (Hymenoptera Anthophoridae) male bees in Madagascar

Observations on territoriality and the associated odour-marking and foraging behaviours in male Pachymelus limbarus Saussure, a Malagasy endemic anthophorid bee, are reported. Data indicated a monandrous mating system where virgin females are attracted, probably by pheromonal cues, to male-patrolled territories associated with flowering, nectariferous Plectran- rhussensu lato species (Lamiaceae). One male observed in detail applied odour marks every 30–80 minutes on twigs around a food-resource area that contained c. 850 flowers. This marking behaviour always preceded territory residence. The male spent c. 80% of his time patrolling. Meanwhile, any intruding flying insect was inspected or chased, which caused conspecific males, as well as often females, to leave the site. The resident male fed frequently on flowers within his territory (c. 3,600 flower-visits on fine days), except immediately following odour-marking bouts. His flower-visiting was often released by interactions with intruding insects entering the territory. The observations provide the first example of male territoriality based on resource defence polygyny in the bee family Anthophoridae. The importance of resource distribution in the evolution of male territoriality in bees is discussed.     

A selection cartridge for rapid detection and analysis of spontaneous mutations including insertions of transposable elements in Enterobacteriaceae

Summary We present a method that allows positive selection and rapid analysis of mutations in Enterobacteriaceae. Mutations are detected in a 2630 bp selection cartridge inserted in two different bacterial mutlicopy plasmid vectors. Spontaneous mutations in Escherichia coli, Enterobacter cloacae and Citrobacter freundii include insertions, deletions and point mutations. The small size of the target sequence facilitates rapid analysis of DNA rearrangements by cleavage with restriction enzymes and of any type of mutation by DNA sequence analysis. While in E. coli insertions of the mobile elements IS1, IS2 and IS5 were readily found, insertions of putative new transposable elements were detected in Enterobacter cloacae. The selection cartridge can thus serve as a tool for studying the spectrum of insertion mutations in Enterobacteriaceae and probably other Gramnegative bacteria, and the dependency of this spectrum on physiological and environmental factors and the host's genetic background can be investigated.     

Refined structure of human carbonic anhydrase II at 2.0 Å resolution

The structure of human erythrocytic carbonic anhydrase II has been refined by constrained and restrained structure–factor least-squares refinement at 2.0 Å resolution. The conventional crystallographic R value is 17.3%. Of 167 solvent molecules associated with the protein, four are buried and stabilize secondary structure elements. The zinc ion is ligated to three histidyl residues and one water molecule in a nearly tetrahedral geometry. In addition to the zinc-bound water, seven more water molecules are identified in the active site. Assuming that Glu-106 is deprotonated at pH 8.5, some of the hydrogen bond donor–acceptor relations in the active site can be assigned and are described here in detail. The Oγ1 atom of Thr-199 donates its proton to the Oε1 atom of Glu-106 and can function as a hydrogen bond acceptor only in additional hydrogen bonds.     

Genetic and blood coagulation characterization of “Swedish” families with von Willebrand's disease types I and III: New aspects of heredity

Summary Twenty-five patients with von Willebrand's disease (vWD) type III were analysed with regard to blood coagulation variables and possible deletions. Nine of the probands and their families were further investigated with DNA linkage analyses. Different patterns of heredity can be suggested in our families with vWD type III, on the basis of blood coagulation analyses. The findings suggest homozygosity in five families and the possibility of compound heterozygosity or a new mutation in the proband in three families. The linkage analyses confirm the results of the coagulation analyses. The segregation of the von Willebrand factor (vWF) gene can be followed in the families, and carrier diagnosis can be made in several of the probands' relatives. The possibility of large deletions in the vWF gene of the probands and their parents was investigated with probes representing the whole vWF cDNA. No deletions were found.This study was approved by the Ethics Committee of the Karolinska Hospital (No. 84:1)     

Regeneration of transgenic plants of Prunus armeniaca containing the coat protein gene of Plum Pox Virus

Summary A system was developed which allows the transfer of foreign genes into apricot cultivars. We report the transformation and regeneration of Prunus armeniaca plants with Agrobacterium tumefaciens strain LBA 4404 containing various binary plasmids, pBinGUSint, carrying the marker gene ß-glucuronidase (GUS) and pBinPPVm, carrying the coat protein gene of Plum Pox Virus (PPV). The marker gene GUS was used for optical evaluation of the efficiency of the transformation system. The coat protein gene of PPV was used to introduce coat protein mediated resistance against one of the most important pathogens of stone fruit trees in Europe and the whole Mediterranean area. This is the first report of the successful integration of a viral coat protein gene into a fruit tree species, opening a new perspective on the control of the disease.Abbreviations GUS ß-glucuronidase - PPV Plum Pox Virus - BA 6-benzylaminopurine - NPTII neomycin phosphotransferase II - CP coat protein - CaMV Cauliflower Mosaic Virus - P35S 35S promoter - MS Murashige and Skoog - PCR polymerase chain reaction - P/C/I phenol/chloroform/isoamylalcohol - RNase ribonuclease - dNTP deoxyribonucleosidetriphosphate - DMSO dimethyl sulfoxide