Functional aspects of the intercentriolar body in the spermiogenesis of Nematoplana coelogynoporoides (Plathelminthes,Proseriata)

Summary The intercentriolar body in the biciliary spermatids of Nematoplana coelogynoporoides and its changes during spermiogenesis are described. Different functional aspects of the body, for example its presumed role as microtubule-organising centre and its influence on cell elongation, are discussed.Abbreviations bb basal body - ce cell elongation - ci cilium - icb intercentriolar body - mt microtubules - n nucleus - r ciliary rootlet     

Taxonomic notes on the genus Strongylopsalis Burr (Dermaptera: Labiidae)

The male and female of a new species of Strongylopsalis are described from Bolivia. Carcinophora boliviana Bormans is redescribed, and its position in the genus Strongylopsalis is confirmed; a new name is proposed for S.boliviana Brindle. A key is given to the ten species now contained in Strongylopsalis, and notes on the distribution of the genus and its possible relationship to Marava are included.     

The taxonomy of the family Paramphistomidae Fischoeder, 1901 with special reference to the morphology of species occurring in ruminants. VIII. The genera Stephanopharynx Fischoeder, 1901 and Balanorchis Fischoeder, 1901

Summary Only Stephanopharynx compactus Fischoeder, 1901 is considered valid under the genus Stephanopharynx Fischoeder, 1901 and S. secundus Stunkard, 1929 and S. coilos Dollfus, 1963 are regarded as its synonyms. The species is redescribed and illustrated based on new material and scanning electron photomicrographs of its tegumental surfaces and the internal surface of its pharyngeal pouch are provided. Balanorchis anastrophus Fischoeder, 1901, the one and only species of the genus Balanorchis Fischoeder, 1901 is redescribed and illustrated. Photomicrographs of its tegumental surfaces as revealed by scanning electron microscopy are given. Additional information on Bilatorchis papillogenitalis Eduardo, 1980 is included. Part of a thesis approved by the University of London for the award of the Ph.D. degree. Part of a thesis approved by the University of London for the award of the Ph.D. degree.     

Industrial importance of the genus <Emphasis Type="BoldItalic">Brevibacterium</Emphasis>

The genus Brevibacterium has long been difficult for taxonomists to classify due to its close morphological similarity to other genera. Since it was proposed in 1953, the genus has often been redefined. The genus is best known for its important role in the ripening of certain cheeses (B. linens) and for its supposed over-production of L-amino acids. Other interesting industrial applications, including the production of ectoine, have recently been proposed. The general characteristics, the occurrence and the recent taxonomy of Brevibacterium are reviewed here. Furthermore, known and potential industrial applications for Brevibacterium species are briefly discussed.     

Enzymatic synthesis of (+)- and (-)-bisdechlorogeodin with sulochrin oxidase from Penicillium frequentans and Oospora sulphurea-ochracea

Sulochrin oxidase is a blue copper-containing glycoenzyme that catalyzes a stereospecific formation of bisdechlorogeodin from sulochrin. The enzyme has been isolated from Penicillium frequentans and Oospora sulphureaochracea which catalyzes the formation of (+)-form and (-)-form of bisdechlorogeodin respectively. The Penicillium enzyme has a molecular weight of 157,000 and contains 19.5% of carbohydrates. Amino acid and carbohydrate compositions are given. The enzyme has probably a dimeric structure containing 6 Cu-atoms. Apparent K _m-values of various substrates are presented. The Oospora enzyme has a molecular weight of 128,000 and except for its stereospecificity its properties are very similar to those of the Penicillium enzyme.     

Stable nuclear transformation of Gonium pectorale

Background  

Green algae of the family Volvocaceae are a model lineage for studying the molecular evolution of multicellularity and cellular differentiation. The volvocine alga Gonium is intermediate in organizational complexity between its unicellular relative, Chlamydomonas, and its multicellular relatives with differentiated cell types, such as Volvox. Gonium pectorale consists of ~16 biflagellate cells arranged in a flat plate. The detailed molecular analysis of any species necessitates its accessibility to genetic manipulation, but, in volvocine algae, transformation procedures have so far only been established for Chlamydomonas reinhardtii and Volvox carteri.     

Genetic and environmental effects on wing polymorphisms in two tropical earwigs (Dermaptera: Labiidae)

Summary The tropical earwigs Paralabella dorsalis and Pseudomarava prominensis are polymorphic for wings in both sexes. An individual's chances of being winged are influenced by whether its parents were winged, by its own sex, and by its nymphal nutrition (at least in P. dorsalis). Wingless females of P. dorsalis lived longer, started ovipositing ealier, and laid slightly larger clutches.     

Listeria monocytogenes exopolysaccharide: origin,structure, biosynthetic machinery and c‐di‐GMP‐dependent regulation

Elevated levels of the second messenger c‐di‐GMP activate biosynthesis of an unknown exopolysaccharide (EPS) in the food‐borne pathogen Listeria monocytogenes. This EPS strongly protects cells against disinfectants and desiccation, indicating its potential significance for listerial persistence in the environment and for food safety. We analyzed the potential phylogenetic origin of this EPS, determined its complete structure, characterized genes involved in its biosynthesis and hydrolysis and identified diguanylate cyclases activating its synthesis. Phylogenetic analysis of EPS biosynthesis proteins suggests that they have evolved within monoderms. Scanning electron microscopy revealed that L. monocytogenes EPS is cell surface‐bound. Secreted carbohydrates represent exclusively cell‐wall debris. Based on carbohydrate composition, linkage and NMR analysis, the structure of the purified EPS is identified as a β‐1,4‐linked N‐acetylmannosamine chain decorated with terminal α‐1,6‐linked galactose. All genes of the pssA‐E operon are required for EPS production and so is a separately located pssZ gene. We show that PssZ has an EPS‐specific glycosylhydrolase activity. Exogenously added PssZ prevents EPS‐mediated cell aggregation and disperses preformed aggregates, whereas an E72Q mutant in the presumed catalytic residue is much less active. The diguanylate cyclases DgcA and DgcB, whose genes are located next to pssZ, are primarily responsible for c‐di‐GMP‐dependent EPS production.     

The cause of mollusk decline on the Ogasawara Islands

Decline of land snails on the Ogasawara Islands was studied. In Hahajima, major alien predators such as Euglandina rosea and Platydemus manokwari are not present, but some small endemic snails, for example, Hirasea spp. and Ogasawarana spp., are already rare and more common endemic snails, for example, Mandarina spp., are also declining in the northern mountains. The decline cannot be directly explained by forest deforestation and by its subsequent regeneration. Three species of flatworms were found to eat small snails under captive conditions. The distribution of these flatworms is restricted to the northern mountains of Hahajima where Mandarina is declining and its survival is low. These predators are plausible candidates as a cause of the decline of the endemic snails.     

Feeding of Hoplias malabaricus in the wetlands of Dulce river (Córdoba,Argentina)

Hoplias malabaricus behaves as a zoophagous and euryphagic species with a strong tendency to eat fish during its entire life. Fish begin to constitute its main food at approximately 200 mm standard length. Insects are important for fish smaller than 50 mm. Crustaceans are of lesser importance for both size groups."Mojarras" (genus Astyanax), the characin Odontostilbe microcephala, and the catfish Pimelodus albicans are its main prey. The relative importance of each prey type varies with predator length.In high summer more food is eaten by H. malabaricus, and digestion rate, related to the higher temperatures, is also higher. During colder seasons feeding activities decreases markedly.     

Trichaptum (Basidiomycota, Hymenochaetales) from China with a description of three new species

Trichaptum imbricatum, T. perenne and T. podocarpi are three new species from China. They are described, illustrated and compared in this paper with similar species. Trichaptum imbricatum is unique in its imbricate basidiocarps, white to cream hymenophores, small and regular pores, and scattered and thin-walled cystidia. Trichaptum perenne differs from other species in the genus in its perennial and pileate habit, its large pores and entire dissepiments, and oblong, ellipsoid basidiospores. Trichaptum podocarpi is distinguished in having totally resupinate basidiocarps, distinctly long cystidia, and in its habitat on Podocarpus. A key to species of Trichaptum occurring in China is provided; statistical variations of spore dimensions for each species are included in the key.     

中国异极衣科地衣二新记录种

该文综合运用形态学、解剖学和化学等方法对山东大型地衣进行分类研究,发现了两个中国新记录种,即德氏蜂窝衣(Heppia despreauxii)和多孢小极衣(Lichinella myriospora).德氏蜂窝衣隶属于蜂窝衣属(Heppia),生于光线充足且裸露的土壤上,主要识别特征为下皮层缺失、子实层IKI+蓝色;多...     

The transmembrane domain of N –acetylglucosaminyltransferase I is the key determinant for its Golgi subcompartmentation

Golgi‐resident type–II membrane proteins are asymmetrically distributed across the Golgi stack. The intrinsic features of the protein that determine its subcompartment‐specific concentration are still largely unknown. Here, we used a series of chimeric proteins to investigate the contribution of the cytoplasmic, transmembrane and stem region of Nicotiana benthamiana N–acetylglucosaminyltransferase I (GnTI) for its cis/medial‐Golgi localization and for protein–protein interaction in the Golgi. The individual GnTI protein domains were replaced with those from the well‐known trans‐Golgi enzyme α2,6–sialyltransferase (ST) and transiently expressed in Nicotiana benthamiana. Using co‐localization analysis and N–glycan profiling, we show that the transmembrane domain of GnTI is the major determinant for its cis/medial‐Golgi localization. By contrast, the stem region of GnTI contributes predominately to homomeric and heteromeric protein complex formation. Importantly, in transgenic Arabidopsis thaliana, a chimeric GnTI variant with altered sub‐Golgi localization was not able to complement the GnTI‐dependent glycosylation defect. Our results suggest that sequence‐specific features in the transmembrane domain of GnTI account for its steady‐state distribution in the cis/medial‐Golgi in plants, which is a prerequisite for efficient N–glycan processing in vivo.     

Nucleotide sequence of the cybB gene encoding cytochrome b561 in Escherichia coli K12

Summary The complete nucleotide sequence of the Escherichia coli cybB gene for diheme cytochrome b ₅₆₁ and its flanking region was determined. The cybB gene comprises 525 nucleotides and encodes a 175 amino acid polypeptide with a molecular weight of 20160. From its deduced amino acid sequence, cytochrome b ₅₆₁ is predicted to be very hydrophobic (polarity 33.7%) and to have three membrane spanning regions. Histidines, canonical ligand residues for protohemes, are localized in these regions, and the heme pockets are thought to be in the cytoplasmic membrane. No significant homology of the primary structure of cytochrome b ₅₆₁ with those of other bacterial b-type cytochromes was observed.     

Chemistry and Pharmacology of Gynostemma pentaphyllum

In traditional Chinese medicine, Gynostemma pentaphyllum (Thunb.) Makino is a herbal drug of extreme versatility and has been extensively researched in China. The dammarane saponins isolated from Gynostemma pentaphyllum, namely gypenosides or gynosaponins, are believed to be the active components responsible for its various biological activities and reported clinical effects. This review attempts to encompass the available literature on Gynostemma pentaphyllum, from its cultivation to the isolation of its chemical entities and a summary of its diverse pharmacological properties attributed to its gypenoside content. Other aspects such as toxicology and pharmacokinetics are also discussed. In vitro and in vivo evidence suggests that Gynostemma pentaphyllum may complement the popular herbal medicine, Panax ginseng, as it also contains a high ginsenoside content and exhibits similar biological activities.     

Brachionus calyciflorus Pallas (Rotatoria) in Inland Waters of Tropical Latitudes Brachionus calyciflorus Tropical in Waters

The widely distributed Brachionus calyciflorus was studied for morphological variation based on material from all tropical areas. The subspecies B. calyciflorus borgerti Apstein is redescribed and its subspecific status affirmed. Various forms with local distributions were noted and described and the morphological differences are attributed to a variety of possible factors. From the distribution patterns it is clear that rotifers are governed by the general principles that apply to other invertebrates and are not cosmopolitan. There are evidently dispersal centres for Brachionus calyciflorus and its subspecies borgerti.     

Responses of Chalcidoidea (Hymenoptera) parasitoids to invasion of the cabbage seedpod weevil (Coleoptera: Curculionidae) in western Canada

Invasion of the European weevil, Ceutorhynchus obstrictus (Marsham), was investigated through surveys of its range and population densities in Alberta and Saskatchewan from 2001 to 2005. After it was first reported in southern Alberta, C. obstrictus rapidly expanded its range and abundance. Our more recent surveys indicate that its northward expansion has slowed, but that it has continued to extend its range eastward to southcentral Saskatchewan. The distribution and abundance of parasitoids of C. obstrictus in Alberta and Saskatchewan were investigated from 2003 to 2005 by mass rearing canola pods infested with C. obstrictus larvae. Although weevil populations were not parasitized for several years immediately following its introduction to southern Alberta, a surprisingly diverse assemblage of Chalcidoidea parasitoids, comprising 12 species from four families, were recently reared from weevil-infested canola siliques in Alberta and Saskatchewan. The Chalcidoidea fauna of C. obstrictus include species with both Nearctic and Holarctic distributions, with some species having restricted host ranges and others that are more niche than taxon-specific. These Chalcidoidea species appear to have expanded their host ranges to parasitize C. obstrictus in the region. Most parasitism is attributable to Trichomalus lucidus (Walker), Chlorocytus sp., and Pteromalus sp. (Pteromalidae), and Necremnus tidius (Walker) (Eulophidae). Parasitism levels varied considerably over the three years of this study. From 2003 to 2005 increases in parasitism occurred among all four of the species dominating the parasitoid fauna of C. obstrictus, but greater increases were observed for Chlorocytus sp. and Pteromalus sp. than for T. lucidus. Parasitoid species have sometimes caused substantial levels of host mortality, although current levels are usually less than 15% for all species combined and so are not sufficient to control weevil populations. Implementing a classical biological control program for C. obstrictus by reconstructing its European natural enemy complex is being considered, but it is still uncertain whether parasitism levels by native Chalcidoidea will increase over time since considerable year-to-year variation has been found. Parasitism levels of C. obstrictus should therefore continue to be monitored to assess whether a classical biological control program should be implemented.     

A new species of Ainudrilus (Tubificidae) from South Georgia,and other subantarctic freshwater oligochaetes

The freshwater oligochaetes of the subantarctic islands are reviewed and new records are given. Ainudrilus dartnalli sp.n. (subfamily Rhyacodrilinae) is described from freshwater sites on South Georgia (South Atlantic Ocean). It differs from the closely related, southwest Australian, A. nharna Pinder & Brinkhurst, by its longer clitellum, the longer upper teeth of its ventral somatic chaetae, its straighter and fewer penial chaetae, and by the proportions of its spermathecae. Range extensions are given for two widespread naidids, Nais variabilis Piguet and N. communis Piguet, from the Falkland Islands (S. Atlantic). Moreover, new material of N. elinguis Müller is recorded from Macquarie Island (Southern Ocean, SW of New Zealand).     

Three New Species of Lagenophryid Peritrichs (Ciliophora) Ectocommensal on Freshwater Decapod Crustaceans from Madagascar1

One species of Lagenophrys and two species of Operculigera are described for the first time. Lagenophrys machaerigera n. sp. was discovered on the freshwater crab Gecarcinautes goudoti and varies between two extreme forms in the structure of its lorica aperture. Operculigera carcini n. sp. was also found on G. goudoti and exhibits several characteristics that set it apart from other members of its genus. Some of these characteristics also suggest a phylogenetic link between O. carcini and the genus Lagenophrys. Operculigera madagascarensis n. sp. was discovered on the parastacid crayfish Astacoides granulimanus. The occurrence of O. madagascarensis on a Madagascan parastacid and other species of Operculigera on Chilean parastacids suggests that parastacids are the oldest hosts of the genus Operculigera. Continental drift is the most likely mechanism by which species of Operculigera and parastacids could have been dispersed to distant parts of the southern hemisphere. The absence of Operculigera on Australian parastacids may be due to its replacement by the genus Setonophrys on those hosts.     

Regulation of amino sugar utilization in Bacillus subtilis by the GntR family regulators,NagR and GamR

In Bacillus subtilis separate sets of genes are implicated in the transport and metabolism of the amino sugars, glucosamine and N‐acetylglucosamine. The genes for use of N‐acetylglucosamine (nagAB and nagP) are found in most firmicutes and are controlled by a GntR family repressor NagR (YvoA). The genes for use of glucosamine (gamAP) are repressed by another GntR family repressor GamR (YbgA). The gamR‐gamAP synton is only found in B. subtilis and a few very close relatives. Although NagR and GamR are close phylogenetically, there is no cross regulation between their operons. GlcN6P prevents all binding of GamR to its targets. NagR binds specifically to targets containing the previously identified dre palindrome but its binding is not inhibited by GlcN6P or GlcNAc6P. GamR‐like binding sites were also found in some other Bacilli associated with genes for use of chitin, the polymer of N‐acetylglucosamine, and with a gene for another GamR homologue (yurK). We show that GamR can bind to two regions in the chi operon of B. licheniformis and that GamR and YurK are capable of heterologous regulation. GamR can repress the B. licheniformis licH‐yurK genes and YurK can repress B. subtilis gamA.