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Piatek M  Vánky K  Mossebo DC  Piatek J 《Mycologia》2008,100(4):662-672
Three recent collections of Doassansiopsis from western Cameroon are assessed taxonomically. Doassansiopsis caldesiae M. Piatek & Vánky is described as a new species from infected leaves of Caldesia reniformis (D. Don) Makino. Its diagnostic characters are flat, nonthickened sori with spore balls as blackish, slightly elevated dots, more or less globoid spores, conspicuous cortical sterile cells and parasitism on Caldesia reniformis of family Alismataceae. The species is compared to another Doassansiopsis species on host plants belonging to family Alismataceae. Doassansiopsis tomasii Vánky is described from two localities on Nymphaea nouchali Burm.f. var. caerulea (Savigny) Verdc. (Nymphaeaceae), which represents the first report of this smut from Cameroon and western Africa. Similarities between this species and Doassansiopsis nymphaeae (Syd. & P. Syd.) Thirum. and D. ticonis M. Piepenbr. are outlined and the global distribution of the three taxa is mapped. The species concept in the genus Doassansiopsis is discussed, and a key to all known species of the genus is provided.  相似文献   

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The study of gill and skin parasites of three fishes species belonging to the genus Clarias: C. camerunensis, C. jaensis and C. pachynema, from the Nyong basin (Cameroon), revealed the presence of two new Monogenean species of the genus Gyrodactylus Nordmann: G. camerunensis n. sp. and G. nyongensis n. sp. parasite of Clarias camerunensis, C. jaensis and C. pachynema. Gyrodactylus camerunensis n. sp. is clearly distinguished from G. nyongensis n. sp. by the smaller size of the haptor sclerites. These two new species differ also from their closest African relatives of the genus Gyrodactylus, G. rysavyi, G. clarii and G. alberti, by the morphology and size of the haptorail sclerites. Their host specificity was discussed and appeared stenoxenous (mesostenoxenous).  相似文献   

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A silicified wood belonging to the Lauraceae family discovered in Africa (Cameroon) is referred to the new genus Beilschmiedioxylon. The important literature concerning the woods of this family shows some difficulties in characterizing the woods of recent genera and, consequently, the fossil ones. So, an inventory of all the Lauracean fossil woods with new precisions and discussions seems to be necessary. This study completes the important work published by Herbert Süss in 1958.  相似文献   

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A continuing study of a collection of marine arthropods from the Upper Cretaceous of Sahel Alma in Lebanon has uncovered a new genus and species of the problematic arthropod group Thylacocephala. The apparent presence of two pairs of antennae constitutes the first available morphological evidence for a close relationship between this species and, by association, all thylacocephalans, and the Crustacea.  相似文献   

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Tsetse flies were sampled in three villages of the Campo sleeping sickness focus in South Cameroon. The aim of this study was to investigate the flies’ gut bacterial composition using culture-dependent techniques. Out of the 32 flies analyzed (27 Glossina palpalis palpalis, two Glossina pallicera, one Glossina nigrofusca, and two Glossina caliginea), 17 were shown to be inhabited by diverse bacteria belonging to the Proteobacteria, the Firmicutes, or the Bacteroidetes phyla. Phylogenetic analysis based on 16S rRNA gene sequences indicated the presence of 16 bacteria belonging to the genera Acinetobacter (4), Enterobacter (4), Enterococcus (2), Providencia (1), Sphingobacterium (1), Chryseobacterium (1), Lactococcus (1), Staphylococcus (1), and Pseudomonas (1). Using identical bacterial isolation and identification processes, the diversity of the inhabiting bacteria analyzed in tsetse flies sampled in Cameroon was much higher than the diversity found previously in flies collected in Angola. Furthermore, bacterial infection rates differed greatly between the flies from the three sampling areas (Akak, Campo Beach/Ipono, and Mabiogo). Last, the geographic distribution of the different bacteria was highly uneven; two of them identified as Sphingobacterium spp. and Chryseobacterium spp. were only found in Mabiogo. Among the bacteria identified, several are known for their capability to affect the survival of their insect hosts and/or insect vector competence. In some cases, bacteria belonging to a given genus were shown to cluster separately in phylogenetic trees; they could be novel species within their corresponding genus. Therefore, such investigations deserve to be pursued in expanded sampling areas within and outside Cameroon to provide greater insight into the diverse bacteria able to infect tsetse flies given the severe human and animal sickness they transmit.  相似文献   

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Cysts with spores showing different degree of maturity and a single plasmodium were observed in the connective tissue of the turbellarian Paravortex cardii located in the digestive lumen of the cockle Cerastoderma edule. The study of spore morphology by transmission electron microscopy revealed that they correspond to an haplosporidian belonging to the genus Urosporidium. Spore ornaments were similar to those described from Urosporidium spisuli, infecting a nematode parasite of the Atlantic surf clam, Spisula solidissima.  相似文献   

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The genus Sericanthe was established and its species were revised 30 years ago by one of the authors. Intensive recent botanical collecting in Lower Guinea (mainly southern Cameroon, Equatorial Guinea and Gabon) has made a reconsideration of species in this area necessary. Revision of the newly collected Lower Guinean herbarium specimens of Sericanthe (twice as many as were available at the time of the first revision) has brought four new species to light, namely S. gabonensis and S. mpassa from Gabon, S. lowryana from Cameroon and S. rabia from Cameroon and Gabon. Distributional data are much augmented, and distributional maps of all species from the area are provided. Four species were reported to be newly recorded for at least one country. The occurrence of the novelties in the main diversity centre of the genus is discussed in the context of the chorology of the entire genus Sericanthe. A first estimation of the conservation status for the new species is given. A synopsis of the genus Sericanthe in Lower Guinea with a taxonomic key is provided. © 2012 The Linnean Society of London, Botanical Journal of the Linnean Society, 2012, 169 , 530–554.  相似文献   

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This study is an investigation on the Keratin of hair coming from 51 non-human Primates belonging to 11 families and 37 different species, using isoelectric focusing on thin layer of polyacrylmide gel (0.5 mm) in pH range 2.5–7.0 followed by silver staining. Our results highlight that animals belonging to the same species have identical isoelectrophoretic patterns. It was proved forLemur fulvus, Macaca fascicularis, Cercopithecus aethiops, Gorilla gorilla. Instead, regarding different species belonging to the same genus, we can say that the pattern obtained was not always characteristic of the species to which the protein belonged. In fact, whereas some species of theCercopithecus, Macaca andPapio genus show significantly different patterns, other species ofCercopithecus, Macaca, Papio, Cebus andSaimiri show identifical patterns. On the other hand, patterns belonging to different genus nearly always showed more marked differences. As for man, by means of this technique, it is possible to show a high number of polypeptides in the 3–4 pH range for non-human Primates as well. Thus, species belonging to different families and genus can always be distinguished; on the other hand, it is not always possible for species of the same genus (e.g.Cebus, Papio).  相似文献   

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Summary We describe, for the first time, the predatory behaviour ofThaumatomyrmex ants on millipedes of the family Polyxenidae, based on field observations ofT. atrox and a field and laboratory study ofT. contumax. The capture of the prey and the removal process of its body-covering setae by the ants before they eat the millipede are described. This specialized behaviour in at least two species of the genus, belonging to two distinct groups of species, indicates a general trend inThaumatomyrmex. We coupled this study with a comparative morphological analysis of the mouthparts and digestive tube of these and otherThaumatomyrmex species. Also, we report the first case of sympatry in the genus, which suggests thatThaumatomyrmex includes several species, and not only one highly variable taxon, as hypothetized earlier.  相似文献   

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The interrelations of the population of microorganisms belonging to the genus Bacteroides with the structures of the mucous membrane of the gastrointestinal tract of germ-free guinea pigs and mini-pigs have been studied. A considerable part of the population of these anaerobic microorganisms is associated in some way with the intestinal mucosa; at least, quite a number of these organisms inhabit mucins covering the mucosa. The determination of this ecological niche occupied by bacteroids in the intestinal microbiocenosis suggests that these organisms have considerable influence on the physiological functions and pathological states of the digestive tract.  相似文献   

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The hypervariable region-1 and four nucleotide positions (10400, 10873, 12308, and 12705) of the coding region of mitochondrial DNA (mtDNA) were analyzed in 441 individuals belonging to eight populations (Daba, Fali, Fulbe, Mandara, Uldeme, Podokwo, Tali, and Tupuri) from North Cameroon and four populations (Bakaka, Bassa, Bamileke, and Ewondo) from South Cameroon. All mtDNAs were assigned to five haplogroups: three sub-Saharan (L1, L2, and L3), one northern African (U6), and one European (U5). Our results contrast with the observed high frequencies of a Y-chromosome haplogroup of probable Asian origin (R1*-M173) in North Cameroon. As a first step toward a better understanding of the evident discrepancy between mtDNA and Y-chromosome data, we propose two contrasting scenarios. The first one, here termed "migration and asymmetric admixture," implies a back migration from Asia to North Cameroon of a population group carrying the haplotype R1*-M173 at high frequency, and an admixture process restricted to migrant males. The second scenario, on the other hand, temed "divergent drift," implies that modern populations of North Cameroon originated from a small population group which migrated from Asia to Africa and in which, through genetic drift, Y-chromosome haplotype R1*-M173 became predominant, whereas the Asian mtDNA haplogroups were lost.  相似文献   

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The African genus LEONARDOXA: (Leguminosae: Caesalpinioideae) comprises two Congolean species and a group of four mostly allopatric subspecies principally located in Cameroon and clustered together in the L. africana complex. LEONARDOXA: provides a good opportunity to investigate the evolutionary history of ant-plant mutualisms, as it exhibits various grades of ant-plant interactions from diffuse to obligate and symbiotic associations. We present in this paper the first molecular phylogenetic study of this genus. We sequenced both the chloroplast DNA trnL intron (677 aligned base pairs [bp]) and trnL-trnF intergene spacer (598 aligned bp). Inferred phylogenetic relationships suggested first that the genus is paraphyletic. The L. africana complex is clearly separated from the two Congolean species, and the integrity of the genus is thus in question. In the L. africana complex, our data showed a lack of congruence between clades suggested by morphological and chloroplast characters. This, and the low level of molecular divergence found between subspecies, suggests gene flow and introgressive events in the L. africana complex.  相似文献   

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A field survey was carried out to investigate the diversity of mycorrhizal fungi associated with Gnetum spp. in Cameroon. The extent and variation of ectomycorrhizal colonisation as well as the degree of host specificity were evaluated. Gnetum spp. were found to be almost always ectomycorrhizal in all sites visited. There were just two ectomycorrhizal morphotypes (‘yellow’ and ‘white’) associated with this plant. Such low diversity is unusual for an ectomycorrhizal plant. The yellow morphotype was the most widespread and prevalent and was identified by morphological and molecular methods to have been formed with Scleroderma sinnamariense. Propagules of this fungus were present in soil collected from farm lands, cocoa plantations, Chromolaena and bush fallows, as well as in a relatively undisturbed forest harbouring ectomycorrhizal legumes. The fungus responsible for the white morphotype was identified as also belonging to the genus Scleroderma by ITS sequence similarity. Arbuscular mycorrhizal structures were absent in cleared and stained portions of the roots.  相似文献   

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Saccharomonospora marina Liu et al. 2010 is a member of the genus Saccharomonospora, in the family Pseudonocardiaceae that is poorly characterized at the genome level thus far. Members of the genus Saccharomonospora are of interest because they originate from diverse habitats, such as leaf litter, manure, compost, surface of peat, moist, over-heated grain, and ocean sediment, where they might play a role in the primary degradation of plant material by attacking hemicellulose. Organisms belonging to the genus are usually Gram-positive staining, non-acid fast, and classify among the actinomycetes. Here we describe the features of this organism, together with the complete genome sequence (permanent draft status), and annotation. The 5,965,593 bp long chromosome with its 5,727 protein-coding and 57 RNA genes was sequenced as part of the DOE funded Community Sequencing Program (CSP) 2010 at the Joint Genome Institute (JGI).  相似文献   

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We report the second human immunodeficiency virus (HIV) belonging to the new HIV type 1 (HIV-1) group P lineage that is closely related to the simian immunodeficiency virus found in gorillas. This virus was identified in an HIV-seropositive male hospital patient in Cameroon, confirming that the group P virus is circulating in humans. Results from screening 1,736 HIV-seropositive specimens collected in Cameroon indicate that HIV-1 group P infections are rare, accounting for only 0.06% of HIV infections. Despite its rarity, group P shows evidence of adaptation to humans.  相似文献   

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This article reports the results of cytogenetic analyses carried out on 10 species of polychaete worms belonging to the genus Ophryotrocha (Dorvilleidae). Nucleolar organizer regions (NORs) were characterized by Ag staining, C-banding, CMA3 staining, and ribosomal fluorescent in situ hybridization (rDNA FISH). Extensive intraspecific variation in NOR number and distribution were observed in O. costlowi, O. sp. macrovifera, O. notoglandulata, O.l. labronica, O. l. pacifica (2n = 6), O. p. puerilis, O. diadema (2n = 8), O. hartmanni, O. gracilis (2n = 10). In O. sp. robusta (2n = 10), Ag-NORs were always located on a single chromosome pair. CMA3 staining suggests a possible trend toward a GC-rich rDNA compartmentalization. In O.l. labronica, O. p. puerilis, O. diadema, and O. sp. robusta rDNA FISH shows that Ag and FISH signals coincide. Results from C-banding seem to indicate that the increased genome size (GS) observed in O. sp. macrovifera (0.8 pg) and O. hartmanni (1.16 pg) compared to the base GS value of the genus (0.4 pg) cannot be attributed to variation in the heterochromatin content.  相似文献   

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