Phyllotaxis in the Oil Palm: Arrangement of Male/Female Florets along the Spikelets

The paper continues an earlier study of the geometry of inflorescencestructures in the oil palm in which geometry is measured interms of Equivalent Phyllotaxis Index (E.P.I.). In this casethe phyllotaxis of male and female florets along their respectivespikelets is considered. Regardless of the spikelet positionon the inflorescence or the palm age the very small male floretshave a higher E.P.I. than the large female structures and acompletely different apparent parastichy arrangement. TheseE.P.I. estimates seem to be independent of the age of palmsfrom which inflorescences and hence spikelets are sampled. However,there is considerable variation in phyllotaxis within bunches,E.P.I. being lower on spikelets sampled toward the base of theinflorescence and increasing in a more or less linear mannerin spikelets sampled at the tip; this pattern is not so definiteon male spikelets. The results are discussed in relation toother more simple measurements of spikelet architecture.     

Reinvestigation of the disulfide bridge arrangement in human pro-opiomelanocortin N-terminal segment (hNT 1-76)

The cystine bridge structure of the amino-terminal fragment of human pro-opiomelanocortin has been reinvestigated. Highly purified amino-terminal fragment 1-76 was rapidly isolated from human pituitaries using only reverse-phase liquid chromatography (RP-HPLC). This peptide was then subjected to trypsin and V8-protease digestion and the products separated by RP-HPLC and subjected to amino acid and microsequence analysis. The results show that disulfide bridges link Cys-2 to Cys-24 and Cys-8 to Cys-20. Amino acid analysis and amino sugar determination confirm (i) the previously proposed sequence and (ii) the suggestion of the presence of two glycosylation sites in this molecule. These are most probably located at Thr-45 (O-glycosylation) and at Asn-65 (N-glycosylation).     

Population Genetics of the Washington National Primate Research Center's (WaNPRC) Captive Pigtailed Macaque (Macaca nemestrina) Population

Pigtailed macaques (Macaca nemestrina) provide an important model for biomedical research on human disease and for studying the evolution of primate behavior. The genetic structure of captive populations of pigtailed macaques is not as well described as that of captive rhesus (M. mulatta) or cynomolgus (M. fascicularis) macaques. The Washington National Primate Research Center houses the largest captive colony of pigtailed macaques located in several different housing facilities. Based on genotypes of 18 microsatellite (short tandem repeat [STR]) loci, these pigtailed macaques are more genetically diverse than captive rhesus macaques and exhibit relatively low levels of inbreeding. Colony genetic management facilitates the maintenance of genetic variability without compromising production goals of a breeding facility. The periodic introduction of new founders from specific sources to separate housing facilities at different times influenced the colony's genetic structure over time and space markedly but did not alter its genetic diversity significantly. Changes in genetic structure over time were predominantly due to the inclusion of animals from the Yerkes National Primate Research Center in the original colony and after 2005. Strategies to equalize founder representation in the colony have maximized the representation of the founders’ genomes in the extant population. Were exchange of animals among the facilities increased, further differentiation could be avoided. The use of highly differentiated animals may confound interpretations of phenotypic differences due to the inflation of the genetic contribution to phenotypic variance of heritable traits. Am. J. Primatol. 74:1017‐1027, 2012. © 2012 Wiley Periodicals, Inc.     

Structural and immunological homology of human and porcine pituitary and plasma IRCM-serine protease 1 to plasma kallikrein: marked selectivity for pairs of basic residues suggests a widespread role in pro-hormone and pro-enzyme processing

IRCM-serine protease 1 (SP1), originally isolated from porcine pituitaries and exhibiting preference for cleavage at pairs of basic residues has now been isolated in sufficient quantities to be structurally characterized from both porcine and human pituitaries and plasmas. Whereas the porcine protease shows a high degree of amino acid sequence homology to human plasma pre-kallikrein, the human homologue exhibits an identity of sequence in the first 25 residues of each chain (regulatory and catalytic chains). In addition, human plasma and pituitary IRCM-SP1 and human plasma pre-kallikrein show virtually identical immunological and molecular properties. These data strongly suggest that IRCM-SP1 and plasma pre-kallikrein originate from the same gene product. Purified extracts from perfused rat pituitaries show that 32% of the IRCM-SP1 activity found in normal rat pituitaries, still remain. These data together with the demonstrated association of IRCM-SP1 with particulate fractions of the pituitary suggest that IRCM-SP1 represents a tissue form of plasma pre-kallikrein. The characterization of the digestion products obtained upon reaction of IRCM-SP1 with pro-insulin, ACTH1-39, pro-dynorphin and pro-enkephalin-derived peptides, somatostatin-28, and a pro-renin-like peptide confirmed the high degree of cleavage selectivity of this enzyme for pairs of basic residues.     

Chemistry and biosynthesis of pro-opiomelanocortin

Studies of lipotropins, melanotropins and endorphins on one hand, and of adrenocorticotropin on the other, has given rise to the concept of a multipotent precursor molecule recently renamed proopiomelanocortin. The preferential sites of cleavage of the precursor to produce its biologically active components are made of pairs of basic amino acid residues as described for the biosynthesis of beta-MSH and pro-insulin. Such structural feature is also found in other pro-hormone molecules. Pulse chase experiments and secretory studies carried out in both anterior and intermediate lobes of rat pituitary glands revealed the transformation of different forms of the precursor into different end-products, the anterior lobe producing preferentially ACTH and beta-LPH while the intermediate produces mainly the alpha-MSH and beta-endorphin. The multiple forms of precursors seem to differ in their carbohydrate content although at least two different gene products are still possible. The presence of similar peptides in the hypothalamus makes it highly probable that neuropeptides are biosynthesized with similar process. Thus the model of beta-LPH precursor, proposed as early as in 1967, is now applicable to the biosynthesis of all other neuropeptides. Major advances in this field are expected in the 1980s.     

Endorphins: structure, roles and biogenesis

The knowledge of the amino acid sequence of both beta-lipotropin (beta-LPH) and gamma-LPH was the starting point that led to the hypothesis, considered revolutionary in 1967, that hormonal precursors exist. This concept was simultaneously proposed for proinsulin and applied later to other polypeptide hormones. The discovery of endorphins brought together two fields of research that were not related: the opiates and the so-called pituitary lipotropic hormones. The demonstration of specific brain opiate receptors led to the hypothesis of the existence of endogenous opiate ligands which could act as neurotransmittors. The isolation of such substances in the brain, first named enkephalins, revealed through their amino acid sequence their structural homology with the pituitary lipolytic hormones. The finding of a more potent opioid substance in the pituitary (beta-endorphin) that comprises the last 31 amino acids of beta-LPH shed a new light on the hypothesis proposed earlier which gave to beta-LPH a role as a precursor molecule. Finally, the addition of ACTH completed a putative multipotent precursor model that has been recently named pro-opiomelanocortin. Pulse-chase experiments have definitely proven that beta-endorphin is a maturation product of a large precursor also containing ACTH and MSH. In other studies, many groups have suggested that endorphins play important roles as possible neuromodulators in pain transmission, in analgesia, in tolerance and dependence, as well as on behavior and endocrine regulations, mainly those related to the hypothalamo-pituitary axes. The elucidation of the biosynthetic process or processes of cerebral endorphins (either enkephalins or beta-endorphin) is of primary importance in order ot understand better their biological as well as regulatory functions. These studies should also be applicable to the biosynthesis of all the other neuronal peptide hormones. It is hoped that they will provide new tools for the study of some important central nervous system functions, such as pain and endocrine control and the physiopathology of behavioral diseases.     

论山东、辽宁寒武系炒米店组底部(古丈阶顶部)小凤凰虫(Fenghuangella Yang in Zhou et al.,1977)北大核心

本文对在山东济南市钢城区九龙山和辽宁东部大连市白家山寒武系炒米店组底部报道的小凤凰虫,进行了详细的描述及修订。根据与小凤凰虫共生的三叶虫对于华北地台区苗岭统与芙蓉统的界线进行了深入探讨,将产有小凤凰虫的Liostracina simesi-Placosema convexa组合带作为华北地台区苗岭统古丈阶最上部的一个化石带,而将Prochuangia mansuyi的首现作为华北地台区芙蓉统排碧阶的底界,对于华南斜坡相区和华北地台区苗岭统和芙蓉统之间界线划分和对比具有重要意义。     

Biosynthesis of beta-endorphin by the neurointermediate lobes from rats treated with morphine or alcohol

Rats were rendered tolerant to either morphine or alcohol, by 21- day drug treatment. The neurointermediate lobes (NIL) were removed and incubated with [³H]-phenylalanine for 3 hrs. The biosynthesized pro-opiomelanocortin (POMC), β-lipotropin (β-LPH) and β-endorphin- like peptides (β-EPLPs) were purified from the total protein extract of the NIL by immunoprecipitation with an antiserum to β-endorphin (β-EP), and analyzed by sodium dodecyl sulfate polyacrylamide disc gel elecrophoresis. The β-EPLPs were further characterized by extraction from the gel and microsequencing. The homology of rat POMC to authentic bovine POMC was established by extraction from the gel and peptide mapping of its tryptic digestion products. Furthermore, the β-endorphin like immunoreactivity (β-EPLI) was estimated in the incubation medium and in the NIL extract. The morphine treatment induced a decrease in the degree of incorporation of [³H]- phenylalanine into POMC, β-LPH and β-EPLPs, associated with a decrease in the content of β-EPLI in the NIL extract and in the incubation medium. Alcohol induced an increase in the degree of incorporation of [³H]-phenylalanine into POMC, β-LPH and β-EPLPs, and an increase in the β-EPLI content in the incubation medium, but no change in the β-EPLI in the NIL extract. These results indicate an effect of chronic morphine and alcohol treatment on the biosynthesis and release of β-EPLPs by the NIL.