天然型与非天然型脱落酸的生物活性比较

采用新方法精制脱落酸（ＡＢＡ）异构体试样,提高了（Ｓ）－（＋）－ＡＢＡ与（Ｒ）－（－）－ＡＢＡ两对映体纯度。抑制生长试验和残留量分析以及气孔闭合试验表明：天然型（Ｓ）－（＋）－ＡＢＡ活性显著高于非天然型（Ｒ）－（－）－ＡＢＡ或（ＳＲ）－（±）－ＡＢＡ。抑制莴苣种子发芽５０％的活性强度,（Ｓ）－（＋）－ＡＢＡ约是（Ｒ）－（－）－ＡＢＡ的５倍,（ＳＲ）－（±）－ＡＢＡ介于两者之间。抑制萝卜下胚轴生长试验,最显著有效期为２～６ｄ,生理作用期约为一周,（Ｓ）－（＋）－ＡＢＡ活性是（Ｒ）－（一）－ＡＢＡ的３．５倍。鸭跖革气孔闭合试验,（Ｓ）－（＋）－ＡＢＡ活性比（Ｒ）－（－）－ＡＢＡ高１倍。     

The heart of the dugong (Dugong dugon) and the west indian manatee (Trichechus manatus) (Sirenia)

Thirty-eight dugong (Dugong dugon) hearts and 28 Florida manatee (Trichechus manatus) hearts were obtained from stranding programs in Australia and the United States. In addition to a double ventricular apex, a feature that has astonished scientists since the eighteenth century, the hearts of both animals have a double subvalvular conus and a dorsal left atrium. The heart lies in a vertical plane at right angles to that of the completely dorsal, symmetrical lungs. The dugong heart has a deeper interventricular cleft and a more conical left ventricle. The latter features may be part of a general morphological trend toward specialization for a more energetic aquatic existence. The presence of a bulbous ascending aorta in the manatee but not in the dugong is without explanation.     

Linkage between the loci for the Lp(a) lipoprotein (LP) and plasminogen (PLG)

Summary A locus, LP, that determines quantitative variation of Lp(a) lipoprotein phenotypes is linked to the plasminogen (PLG) locus (peak lod score =12.73). This linkage relationship assigns a locus with alleles that have an affect on risk for coronary artery disease to the long arm of chromosome 6.     

Characterization of divalent cation localization in the minor groove of the A(n)T(n) and T(n)A(n) DNA sequence elements by (1)H NMR spectroscopy and manganese(II)

The localization of Mn(2+) in A-tract DNA has been studied by (1)H NMR spectroscopy using a series of self-complementary dodecamer oligonucleotides that contain the sequence motifs A(n)(n) and T(n)A(n), where n = 2, 3, or 4. Mn(2+) localization in the minor groove is observed for all the sequences that have been studied, with the position and degree of localization being highly sequence-dependent. The site most favored for Mn(2+) localization in the minor groove is near the 5'-most ApA step for both the T(n)A(n) and the A(n)T(n) series. For the T(n)A(n) series, this results in two closely spaced symmetry-related Mn(2+) localization sites near the center of each duplex, while for the A(n)T(n) series, the two symmetry-related sites are separated by as much as one half-helical turn. The degree of Mn(2+) localization in the minor groove of the T(n)A(n) series decreases substantially as the AT sequence element is shortened from T(4)A(4) to T(2)A(2). The A(n)T(n) series also exhibits length-dependent Mn(2+) localization; however, the degree of minor groove occupancy by Mn(2+) is significantly less than that observed for the T(n)A(n) series. For both A(n)T(n) and T(n)A(n) sequences, the 3'-most AH2 resonance is the least broadened of the AH2 resonances. This is consistent with the observation that the minor groove of A-tract DNA narrows in the 5' to 3' direction, apparently becoming too narrow after two base pairs for the entry of a fully hydrated divalent cation. The results that are reported illustrate the delicate interplay that exists between DNA nucleotide sequence, minor groove width, and divalent cation localization. The proposed role of cation localization in helical axis bending by A-tracts is also discussed.     

Obesity and variants of the GHRL (ghrelin) and BCHE (butyrylcholinesterase) genes

Ghrelin coded by the GHRL gene is related to weight-gain, its deactivation possibly depending on its hydrolyzation by butyrylcholinesterase (BChE) encoded by the BCHE gene, an enzyme already associated with the body mass index (BMI). The aim was to search for relationships between SNPs of the GHRL and BCHE genes with BChE activity, BMI and obesity in 144 obese and 153 nonobese Euro-Brazilian male blood donors. In the obese individuals, a significant association with higher BChE activity, in the 72LM+72MM; -116GG genotype class (GHRL and BCHE genes, respectively) was noted. No significant differences were found otherwise, through comparisons between obese and control individuals, of genotype and allele frequencies in SNPs of the GHRL gene (Arg51Gln and Leu72Met), or mean BMI between 72LL and 72LM+72MM genotypes. Although there appears to be no direct relationship between the examined GHRL SNPs and BMI, the association of the 72M SNP with higher BChE activity in obese subjects probably points to a regulatory mechanism, thereby implying the influence of the GHRL gene on BChE expression, and a consequential metabolic role in the complex process of fat utilization.     

Structural requirements of echistatin for the recognition of alpha(v)beta(3) and alpha(5)beta(1) integrins

There are key differences between the amino acid residues of the RGD loops and the C termini of echistatin, a potent antagonist of alpha(IIb)beta(3), alpha(v)beta(3) and alpha(5)beta(1), and eristostatin, a similar disintegrin selectively inhibiting alpha(IIb)beta(3). In order to identify echistatin motifs required for selective recognition of alpha(v)beta(3) and alpha(5)beta(1) integrins, we expressed recombinant echistatin, eristostatin, and 15 hybrid molecules. We tested them for their ability to inhibit adhesion of different cell lines to fibronectin and von Willebrand factor and to express ligand-induced binding site epitope. The results showed that Asp(27) and Met(28) support recognition of both alpha(v)beta(3) and alpha(5)beta(1). Replacement of Met(28) with Asn completely abolished echistatin's ability to recognize each of the integrins, while replacement of Met(28) with Leu selectively decreased echistatin's ability to recognize alpha(5)beta(1) only. Eristostatin in which C-terminal WNG sequence was substituted with HKGPAT exhibited new activity with alpha(5)beta(1), which was 10-20-fold higher than that of wild type eristostatin. A hypothesis is proposed that the C terminus of echistatin interacts with separate sites on beta(1) and beta(3) integrin molecules.     

The populations of Pseudophoxinus zeregi (Heckel) in Israel and Syria and the status of Pseudophoxinus (Pararhodeus) drusensis (Pellegrin) (Pisces:Cyprinidae)

Pseudophoxinus zeregi (Heckel) and P. (Pararhodeus) drusensis (Pellegrin) have been examined from populations near their respective type localities. It was found that there is no basis for the subgenus Pararhodeus and that the two forms are best regarded as subspecies of Pseudophoxinus zeregi.     

On the Knowledge of Coprophilus (Zonyptilus) pennifer (Motschulsky, 1845) and Coprophilus (Zonyptilus) marginalis (Reitter, 1894) (Coleoptera,Staphylinidae)

Entomological Review - The type and other extensive material of Coprophilus (Zonyptilus) pennifer (Motschulsky, 1845) and some of its synonyms was examined. Coprophilus (Zonyptilus) marginalis...     

Determinants of ligand binding specificity of the alpha(1)beta(1) and alpha(2)beta(1) integrins.

The alpha(1)beta(1) and alpha(2)beta(1) integrins are cell surface collagen receptors. Cells expressing the alpha(1)beta(1) integrin preferentially adhere to collagen IV, whereas cells expressing the alpha(2)beta(1) integrin preferentially adhere to collagen I. Recombinant alpha(1) and alpha(2) integrin I domains exhibit the same collagen type preferences as the intact integrins. In addition, the alpha(2) integrin I domain binds echovirus 1; the alpha(1) I domain does not. To identify the structural components of the I domains responsible for the varying ligand specificities, we have engineered several alpha(1)/alpha(2) integrin I domain chimeras and evaluated their virus and collagen binding activities. Initially, large secondary structural components of the alpha(2) I domain were replaced with corresponding regions of the alpha(1) I domain. Following analysis in echovirus 1 and collagen binding assays, chimeras with successively smaller regions of alpha(1) I were constructed and analyzed. The chimeras were analyzed by ELISA with several different alpha(2) integrin monoclonal antibodies to assess their proper folding. Three different regions of the alpha(1) I domain, when present in the alpha(2) I domain, conferred enhanced collagen IV binding activity upon the alpha(2) I domain. These include the alpha3 and alpha5 helices and a portion of the alpha6 helix. Echovirus 1 binding was lost in a chimera containing the alphaC-alpha6 loop; higher resolution mapping identified Asn(289) as playing a critical role in echovirus 1 binding. Asn(289) had not been implicated in previous echovirus 1 binding studies. Taken together, these data reveal the existence of multiple determinants of ligand binding specificities within the alpha(1) and alpha(2) integrin I domains.     

Fauna and biology of the mosquitoes (Culicidae) of the Chara valley (Chita Province)

The specific composition and the nature of domination of bloodsucking mosquitoes from the Charskaya hollow were studied. The abundance dynamics of attacking females was registered by means of Berezantzev's bell. Data were obtained on the hatching sites of mosquitoes and peculiarities of seasonal adaptation of some species in connection with the availability of various landscapes with different microclimatic conditions.     

Taxonomic revision of the Kimmeridgian (Upper Jurassic) genusMesosimoceras (Ammonoidea) and institution of the new genusPresimoceras (Ammonitina,Idoceratinae)

Presimoceras is a new genus of Idoceratinae. The biostratigraphical range ofPresimoceras is limited to theStrombecki, Divisum and lower part of theAcanthicum Zone within the Kimmeridgian (in the Southern European sense). The genusMesosimoceras (Idoceratinae) was instituted by Spath (1925), withSimoceras cavouri Gemmellaro as type species; this genus is here emended with the institution ofPresimoceras n. gen. The species groupcavouri-risgoviense is preserved in the emended genusMesosimoceras, while the groupherbichiludovicii-teres is accommodated inPresimoceras on account of the radical and numerous differences and the stratigraphical gap betweenMesosimoceras andPresimoceras. As type species of the new genusAmmonites nodulatus Quenstedt is designated. The new genus is here subdivided into three groups of species:herbichi, ludovicii andteres. Phylogenetically,Presimoceras is derived fromPassendorferia, Mesosimoceras fromNebrodites.     

Proopiomelanocortin (POMC) and testing the phylogenetic position of turtles (Testudines)

Morphological and molecular studies have inferred multiple hypotheses for the phylogenetic relationships of Testudines. The hypothesis that Testudines are the only extant anapsid amniotes and the sister taxon of diapsid amniotes is corroborated by morphological studies, while the hypothesis that Testudines are diapsid amniotes is corroborated by more recent molecular and morphological studies. In this study, the placement of Testudines is tested using the full length cDNA sequence of the polypeptide hormone precursor proopiomelanocortin (POMC). Because only extant taxa have been used, the hypotheses being tested are limited to the following (1) Testudines as the sister taxon of Archosauria, (2) Testudines included in Archosauria and the sister taxon of Crocodilia, (3) Testudines as the sister taxon of Lepidosauria, (4) Testudines as the sister taxon of Sauria, and (5) Testudines as the sister taxon of a monophyletic Mammalia–Sauria clade. Neither Maximum likelihood, Bayesian, or maximum parsimony analyses are able to falsify the hypothesis of (Archosauria (Lepidosauria, Testudines)) and as such is the preferred inference from the POMC data.     

Honeyeater (Meliphagidae) pollination and the floral biology of PolynesianHeliconia (Heliconiaceae)

The primary pollinator of Polynesian heliconias,Heliconia laufao andH. paka, is the Wattled Honeyeater,Foulehaio carunculata. This report is the first documentation of pollination by honeyeaters in the genusHeliconia and the first record ofF. carunculata as a pollinator of a plant species. The Polynesian heliconias bear inflorescences that produce 2–4 hermaphroditic flowers per day for a period of 2–3 months. Each flower secretes abundant nectar (125–184 l) with low sugar concentration (15–18% sucrose-equivalents, weight per weight basis) which is available at anthesis just before dawn. Ninety percent of flower visits occur between anthesis and mid-morning. The honeyeaters perch on inflorescence bracts, and probing of the flower results in pollen deposition on the head and bill from where pollen is transferred between flowers. No statements on compatibility can be made forHeliconia paka; however,Heliconia laufao appears to be self-compatible. Calculations of energetic values of nectar of the Polynesian heliconias and Daily Energy Expenditures ofF. carunculata suggest that populations ofH. laufao andH. paka serve as rich energy resources for their pollinators.