The structure of 2-carboxyquinolinatobis(triphenylphosphite)rhodium(I)

2-Carboxyquinolinatobis(triphenylphosphite)rhodium (I) was prepared by means of the following reaction: [Rh(Qin)(CO)₂] + 2P(OPh)₃→ [Rh(Qin)(P(OPh)₃)₂] + 2CO It crystallizes in the triclinic space groupP] witha = 12.406,b = 18.702,c = 9.547 Å, α = 76.36, β = 111.35, γ = 97.88^o and Z = 2. The structure was determined from 4520 observed reflections. the final R value was 0.051. The RhP bond distances may indicate (although the difference is only about 3σ) that the nitrogen atom the chelate ring has the largest trans influence. The chelate ring is significantly folded along the N---O axis.     

Taxonomic notes on some advanced Tournaisian (Mississippian) siphonodellids (Conodonta)

Traditionally, biostratigraphy of the terminal Famennian (Upper Devonian) and lower part of the Tournaisian (Mississippian) is based on phylogeny of the conodont genus Siphonodella Branson and Mehl. This study is focused on a Siphonodella species with a long taxonomical history. For the last three decades it was known as S. hassi Ji, 1985 and was used as a zonal index for the eponymic hassi Zone, used worldwide. However, this species faces several taxonomical problems. The main issue is the homonymy of S. hassi and S. cooperi hassi Thompson and Fellows, 1970. However, S. cooperi hassi is a subjective junior synonym of S. obsoleta Hass, 1959. The oldest junior synonym of S. hassi is S. wilberti Bardasheva, Bardashev, Weddige and Ziegler, 2004, and, according to a statement by the International Commission on Zoological Nomenclature, the latter represents the only available name for this species. An additional problem is the similar morphology of early ontogenetic stages of S. wilberti and S. quadruplicata Branson and Mehl, 1944, the youngest stratigraphically important siphonodellid species. In advanced ontogenetic stages, P₁ elements that possess two rostral ridges belong to S. wilberti only. The smaller P₁ elements having two or less rostral ridges comprise the S. wilberti- S. quadruplicata plexus. Maintenance of the wilberti Zone in the Tournaisian global zonation is suggested.     

Hydrotris(1-pyrazolyl)borates of chromium(III)

The preparation and characterization of dichloro- (hydrotris(1-pyrazolyl)borato)pyridinechromium(III), CrCl₂(HB(PYZ)₃)Py, (Py = pyridine and HB(PYZ)₃^-1 is the hydrotris(1-pyrazolyl)borato anion) is described. The structure of the compound was determined by single crystal X-ray diffraction. Crystals were monoclinic, P2₁/c, a = 11.603(2), b = 9.845(1), c = 16.095(2) Å, β = 96.04(1)° with four formula units in the unit cell. Intensities were measured on a Nicolet P3 diffractometer with use of Mokα radiation. The structure was solved by standard methods and refined to R₁ = 0.0601, R₂ = 0.0397 based on 3142 independent reflections. Bond lengths and angles are normal. The pyridine molecule is oriented such that the plane bisects the angle between the two cis pyrazole rings. The synthesis and preparation of the related Cr(III) species CrCl₂(HB(PYZ)₃)pyrazole, Ph₄As[CrCl₃HB(PYZ)₃] and [Cr(HB(PYZ)₃)₂]PF₆ are described and the evaluation of the CrCl₂(HB(PYZ)3)L (L = pyridine or pyrazole) species for genotoxicity is discussed.     

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.     

Electronic structures of collagen model polymers: (Gly-Pro)n, (Gly-Hyp)n, (Ala-Pro)n, (Ala-Hyp)n, (Gly-Pro-Gly)n, (Gly-Hyp-Gly)n, (Gly-Pro-Pro)n, and (Gly-Pro-Hyp)n

In order to investigate the relationship existing between the electronic structures of collagen and its biochemical functions in vivo, the semiempirical CNDO/2 SCF MO calculations were carried out on several model polymers of collagen, (Gly-Pro)_n, (Gly-Hyp)_n, (Ala-Pro)_n, (Ala-Hyp)_n, (Gly-Pro-Gly)_n, (Gly-Hyp-Gly)_n, (Gly-Pro-Pro)_n and (Gly-Pro-Hyp)_n. Geometries of the skeleton of these polymers were assumed to be the same as those of poly(l-proline) I (cis) and II (trans) and the calculations were performed only on infinite polymers in a single chain. The results show that the cis form is always more stable than the trans form for all the polymers treated. This energy difference between the cis and trans forms depends, for example, on the kind of amino acid residue, Gly or Ala, but this could not be seen in the Pro or Hyp residue. The flexibility or mobility of the collagen structure was explained using the energy difference between the cis and trans forms of the polymers, i.e. the cis-trans conversion of the collagen was discussed in connection with the energy difference. The reason why the collagen has the constitution of (Gly-Pro-Hyp)_n is briefly discussed.     

The Cochlostoma (Holcopoma) westerlundi group in Italy (Caenogastropoda: Cochlostomatidae)

Currently, the Cochlostoma (Holcopoma) westerlundi (Paulucci, 1879) group includes three subspecies inhabiting southern Italy up to southeastern Sicily. C. w. westerlundi (Paulucci, 1879) is limited to southern Calabria, C. w. yapigium (Westerlund, 1885) is widespread across the Salento (the southeastern extremity of the Apulia region) and C. w. dionysii (Paulucci, 1879) is endemic to the environs of Siracusa (SE Sicily). There is also a fourth taxon, C. paganum (Westerlund, 1885) described for Otranto (LE, Apulia), considered a synonym of C. w. yapigium. Up to now, the molecular genetics of C. westerlundi s.l. have been unknown and the morphological data of several populations are still lacking. Hence, the systematic classification of the group is tentative. Aiming at filling this gap, mtDNA (16S rDNA and COI) partial sequences were investigated and, in addition, the reproductive apparatus of C. w. westerlundi was described for the first time. Molecular sequences and anatomical data were used to test the taxonomic and phylogenetic status of the examined populations. Maximum Likelihood and Bayesian analysis revealed three clusters, strongly supported, corresponding to the three taxa. For the first time, synonymy between paganum and yapigium was confirmed by molecular evidence. Genetic distances between groups (D_xyJC) ranged from 2.6% to 5% (16S rDNA) and from 6.3% to 8.3% (COI). Molecular and morphological data led us to suggest elevating the three subspecies to the species rank.     

Uptake Hydrogenase (Hup) in Common Bean (Phaseolus vulgaris) Symbioses

Strains of Rhizobium forming nitrogen-fixing symbioses with common bean were systematically examined for the presence of the uptake hydrogenase (hup) structural genes and expression of uptake hydrogenase (Hup) activity. DNA with homology to the hup structural genes of Bradyrhizobium japonicum was present in 100 of 248 strains examined. EcoRI fragments with molecular sizes of approximately 20.0 and 2.2 kb hybridized with an internal SacI fragment, which contains part of both bradyrhizobial hup structural genes. The DNA with homology to the hup genes was located on pSym of one of the bean rhizobia. Hup activity was observed in bean symbioses with 13 of 30 strains containing DNA homologous with the hup structural genes. However, the Hup activity was not sufficient to eliminate hydrogen evolution from the nodules. Varying the host plant with two of the Hup⁺ strains indicated that expression of Hup activity was host regulated, as has been reported with soybean, pea, and cowpea strains.     

Chromosome numbers in antlions (Myrmeleontidae) and owlflies (Ascalaphidae) (Insecta,Neuroptera)

A short review of main cytogenetic features of insects belonging to the sister neuropteran families Myrmeleontidae (antlions) and Ascalaphidae (owlflies) is presented, with a particular focus on their chromosome numbers and sex chromosome systems. Diploid male chromosome numbers are listed for 37 species, 21 genera from 9 subfamilies of the antlions as well as for seven species and five genera of the owlfly subfamily Ascalaphinae. The list includes data on five species whose karyotypes were studied in the present work. It is shown here that antlions and owlflies share a simple sex chromosome system XY/XX; a similar range of chromosome numbers, 2n = 14-26 and 2n = 18-22 respectively; and a peculiar distant pairing of sex chromosomes in male meiosis. Usually the karyotype is particularly stable within a genus but there are some exceptions in both families (in the genera Palpares and Libelloides respectively). The Myrmeleontidae and Ascalaphidae differ in their modal chromosome numbers. Most antlions exhibit 2n = 14 and 16, and Palparinae are the only subfamily characterized by higher numbers, 2n = 22, 24, and 26. The higher numbers, 2n = 20 and 22, are also found in owlflies. Since the Palparinae represent a basal phylogenetic lineage of the Myrmeleontidae, it is hypothesized that higher chromosome numbers are ancestral for antlions and were inherited from the common ancestor of Myrmeleontidae + Ascalaphidae. They were preserved in the Palparinae (Myrmeleontidae), but changed via chromosomal fusions toward lower numbers in other subfamilies.     

Redescription of Diesingium lomentaceum (Diesing, 1850) (Cestoda: Trypanorhyncha)

Ardeirhynchus spiralis (Rudolphi, 1809) n. g., n. comb. (syns Echinorhynchus spiralis, Prosthorhynchus spiralis and Plagiorhynchus spiralis), a parasite of herons (Ciconiiformes: Ardeidae), is redescribed on the basis of the holotype from Ixobrychus minutus and specimens from Ardeola ralloides (new host record) in Bulgaria. A. spiralis is a member of the family Polymorphidae and not of the Plagiorhynchidae in which it was previously classified. Ardeirhynchus n. g. is distinguished from the most morphologically similar genus, Arhythmorhynchus Lühe, 1911, by the position of the male genital system, which occupies the posterior 1/8-1/6 part of the trunk, the distribution of hypodermal nuclei in groups in the anterior part and in lateral rows along the length of the posterior part of the trunk, a considerably shorter neck, minute trunk spines and a terminal genital pore.     

Occurrence of Stiretrus decastigmus (Herrich-Schaeffer) (Hemiptera: Pentatomidae) Preying on Microtheca semilaevis Stal (Coleoptera: Chrysomelidae)

Microtheca semilaevis Stal is a phythophagous insect associated to Brassicaceae, and frequently occurs with other species of beetles, such as Microtheca ochroloma Stal. Despite its importance to organic farmers, there is no information in the Brazilian literature about its natural enemies. Stiretrus decastigmus (Herrich-Schaeffer) was first found and here reported preying an adult of M. semilaevis in Chinese cabbage in Santa Maria, RS, Brazil (29°43??28??S, 53°43??19??W).     

Screening for Booroola (FecB) and Galway (FecXG) mutations in Indian sheep

This study reports the status of the Booroola (FecB) and Galway (FecX^G) mutations in Indian sheep breeds. The Kendrapada sheep (n = 46) was genotyped for the presence of FecB and FecX^G mutations, while the Garole (n = 34), Malpura (n = 30), and Decanni sheep (n = 15) for the FecX^G mutation. The FecB and FecX^G genotyping was carried out by forced restriction fragment length polymorphism PCR technique. In the present study, FecB mutation was discovered in the Kendrapada sheep of Orissa, which is now the second prolific sheep of India after the Garole. Out of 46 individuals of Kendrapada sheep, 26 were homozygous (BB), 15 heterozygous (B+) and 5 non-carriers (++) for the FecB mutation. The frequency of the FecB allele in this sample was about 0.73. Results indicated that the frequency of the FecB mutation is high, but the gene is not fixed in the population as reported in Garole sheep. None of sheep breeds carried the FecX^G mutation. The discovery of the FecB mutation in Kendrapada sheep will facilitate the use of FecB allele in improving the prolificacy of non-prolific sheep breeds of India.     

Analysis of a Streptomyces coelicolor A3(2) locus containing the nucleoside diphosphate kinase (ndk) and folylpolyglutamate synthetase (folC) genes

A 3.6-kb DNA fragment from Streptomyces coelicolor A3(2) with the genes valS probably encoding a valyl-tRNA synthetase, folC encoding folylpolyglutamate synthetase, and ndk encoding a nucleoside diphosphate kinase was analysed. folC and ndk are separated by a small open reading frame of unknown function, orfX. The deduced folC gene product is a protein of 46 677 Da whose sequence is similar to other folylpolyglutamate synthetases and folylpolyglutamate synthetase-dihydrofolate synthetases from both Gram-positive and Gram-negative bacteria. After cloning folC behind the lacZ promoter, the Streptomyces folC complemented a folC mutant of Escherichia coli. An essential function for Streptomyces folC was suggested by the fact that it could not be mutated using a conventional gene disruption technique.     

Preparation and structure of bis(trifluoroacetato)dicarbonyl bis(triethylphosphine)molybdenum(lI)

The Mo(CO)₂(PEt₃)₂(CF₃COO)₂ complex, obtained by prolonged reaction of trifluoroacetic acid with Mo(CO)₃(PEt₃₎₃ in dichloromethane, was characterized by spectroscopic methods and by X-ray crystal structure determination. The crystals belong to the monoclinic space group Cc, with a = 20.037, b = 10.879, _c = 15.176 Å,β/3 = 129.28° and _Z = 4. The structure was refined on 2135 observed reflections to R = 0.047. The Mo(II) atom is 7-coordinated and has a capped trigonal prism geometry, the capping position being occupied by a monodentate CF₃CO₂ ligand. The quadrangular plane contains one CO, one PEt₃ and one bidentate CF₃CO₂ ligand. The remaining CO and PEt₃ molecules are found on the opposite edge.     

Preparation and characterization of (9-methyladenine)triammineplatinum(II) and trans-dihydroxo(9-methyladenine)triammineplatinum(IV) complexes

The preparation is reported of [(NH₃)₃Pt(9- MeA)] X₂ (9-MeA = 9-methyladenine) with XCl (1a) and XClO₄ (1b) and of trans-[(OH)₂Pt(NH₃)₃- (9-MeA)]X₂ with XCl (2a) and XClO₄ (2b), and the crystal structure of 1b. [(NH₃)₃Pt(C₆H₇N₅)](ClO₄)₂ crystallizes in space group P2₁/n with a = 20.810(7) Å, b = 7.697(3) Å, c = 10.567(4) Å, β = 91.57(6)°, Z = 4. The structure was refined to R = 0.054, R_w = 0.063. In all four compounds Pt coordination is through N7 of 9-MeA, as is evident from ³J coupling between H8 of the adenine ring and ¹⁹⁵Pt. Pt(II) and Pt(IV) complexes can be differentiated on the basis of different ³J values, larger for Pt(II) than for Pt(IV) by a factor of 1.57 (av). In Me₂SO-d₆, hydrogen bonding occurs between Cl^? and C(8)H of 9-MeA as weil as between Cl^? and the NH₃ groups in the case of the Pt(II) complex 1a. Protonation of the 9-MeA ligands was followed using ¹H NMR spectroscopy and pK_a values for the N1 protonated 9-MeA ligands were determined in D₂O. They are 1.9 for 1a and 1.8 for 2a, which compares with 4.5 for the non-platinated 9-MeA. Possible consequences for hydrogen bonding with the complementary bases thymine or uracil are discussed briefly. Protonation of the OH groups in the Pt(IV) complexes has been shown not to occur above pH 1.     

PhaM Is the Physiological Activator of Poly(3-Hydroxybutyrate) (PHB) Synthase (PhaC1) in Ralstonia eutropha

Poly(3-hydroxybutyrate) (PHB) synthase (PhaC1) is the key enzyme of PHB synthesis in Ralstonia eutropha and other PHB-accumulating bacteria and catalyzes the polymerization of 3-hydroxybutyryl-CoA to PHB. Activity assays of R. eutropha PHB synthase are characterized by the presence of lag phases and by low specific activity. It is assumed that the lag phase is caused by the time necessary to convert the inactive PhaC1 monomer into the active dimeric form by an unknown priming process. The lag phase can be reduced by addition of nonionic detergents such as hecameg [6-O-(N-heptyl-carbamoyl)-methyl-α-d-glucopyranoside], which apparently accelerates the formation of PhaC1 dimers. We identified the PHB granule-associated protein (PGAP) PhaM as the natural primer (activator) of PHB synthase activity. PhaM was recently discovered as a novel type of PGAP with multiple functions in PHB metabolism. Addition of PhaM to PHB synthase assays resulted in immediate polymerization of 3HB coenzyme A with high specific activity and without a significant lag phase. The effect of PhaM on (i) PhaC1 activity, (ii) oligomerization of PhaC1, (iii) complex formation with PhaC1, and (iv) PHB granule formation in vitro and in vivo was shown by cross-linking experiments of purified proteins (PhaM, PhaC1) with glutardialdehyde, by size exclusion chromatography, and by fluorescence microscopic detection of de novo-synthesized PHB granules.     

Macrocyclic nickel(II) complexes: Spectroscopic studies and crystal structure of bis(difluoroboron-alpha-furilglyoximato)nickel(II)

Bis (difluoroboron - α - furilglyoximato) nickel (II), C₂₀H₁₂O₈N₄B₂F₄Ni, was prepared by cyclization of its hydrogen-bonded precursor with BF₃·OEt₂. The compound crystallizes in the space group P2₁/_c with a = 11.162(2), b = 5.569(2), c = 19.527(3) Å, β = 100.08(1)°, U = 1195.1(3) ų, and Z = 2. The structure was refined to an R value of 0.033 using 2371 unique reflections collected with a CAD4-SDP diffractometer system. Unlike the corresponding planar macrocyclic as well as hydrogen-bonded dimethylglyoximates, the title compound neither dimerizes not exhibits columnar stacked structure. The 14-member macrocycle is planar except the B atoms, and no metal-metal interactions are observed in this compound. The complexation and cyclization reactions were investigated using spectral data. The structure is compared with other macrocyclic complexes.     

Growth of Pseudomonas mendocina on Fe(III) (Hydr)Oxides

Although iron (Fe) is an essential element for almost all living organisms, little is known regarding its acquisition from the insoluble Fe(III) (hydr)oxides in aerobic environments. In this study a strict aerobe, Pseudomonas mendocina, was grown in batch culture with hematite, goethite, or ferrihydrite as a source of Fe. P. mendocina obtained Fe from these minerals in the following order: goethite > hematite > ferrihydrite. Furthermore, Fe release from each of the minerals appears to have occurred in excess, as evidenced by the growth of P. mendocina in the medium above that of the insoluble Fe(III) (hydr)oxide aggregates, and this release was independent of the mineral's surface area. These results demonstrate that an aerobic microorganism was able to obtain Fe for growth from several insoluble Fe minerals and did so with various growth rates.     

Efficacy of the parasitoid,Diaeretiella rapae (McIntosh) (Hymenoptera: Braconidae) against Myzus persicae (Sulzer) (Hemiptera: Aphididae) infesting rapeseed-mustard

Efficacy of Diaeretiella rapae (McIntosh) (Hymenoptera: Braconidae) was determined by studying its biological and behavioural attributes on the aphid, Myzus persicae (Sulzer) (Hemiptera: Aphididae). Total developmental duration of the parasitoid was longer in younger instars compared to that in older instars of aphid. Host age negatively affected the oviposition period and fecundity of the ovipositing parasitoid. Survival of the immatures was higher in older than the younger instars of the aphid. Sex ratio for the parasitoid was female-biased. Longevity of female parasitoid was higher while parasitizing aphid nymphs of younger age groups (1–2 days old) compared to that of older age groups (4–5 days old). Parasitoid showed a higher preference towards second instar of M. persicae both in choice and no-choice tests. Results on mutual interference revealed that per capita searching efficiency decreased from 0.91 to 0.07 as parasitoid densities increased from 1 to 8. Logistic regression exhibited a type II functional response for D. rapae. The estimated values of search-efficiency (a) and handling time (T_h) were 0.038 h⁻¹ and 1.59 h, respectively. The maximum parasitization rate was 15.08. This investigation suggests that D. rapae could be an effective candidate for augmentative biological control of M. persicae which infests several plant species of economic importance.