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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Characterisation of arthrobacters by pyrolysis mass spectrometry

Bovonsombut, Sakunnee January 2000 (has links)
No description available.
22

Computer assisted classification and identification of actinomycetes

Chun, Jongsik January 1995 (has links)
Three computer software packages were written in the C++ language for the analysis of numerical phenetic, 16S rRNA sequence and pyrolysis mass spectrometric data. The X program, which provides routines for editing binary data, for calculating test error, for estimating cluster overlap and for selecting diagnostic and selective tests, was evaluated using phenotypic data held on streptomycetes. The AL16S program has routines for editing 16S rRNA sequences, for determining secondary structure, for finding signature nucleotides and for comparative sequence analysis; it was used to analyse 16S rRNA sequences of mycolic acid-containing actinomycetes. The ANN program was used to generate backpropagation-artificial neural networks using pyrolysis mass spectra as input data. Almost complete 1 6S rDNA sequences of the type strains of all of the validly described species of the genera Nocardia and Tsukamurel!a were determined following isolation and cloning of the amplified genes. The resultant nucleotide sequences were aligned with those of representatives of the genera Corynebacterium, Gordona, Mycobacterium, Rhodococcus and Turicella and phylogenetic trees inferred by using the neighbor-joining, least squares, maximum likelihood and maximum parsimony methods. The mycolic acid-containing actinomycetes formed a monophyletic line within the evolutionary radiation encompassing actinomycetes. The "mycolic acid" lineage was divided into two clades which were equated with the families Coiynebacteriaceae and Mycobacteriaceae. The family Coiynebacteriaceae contained the genera Cotynebacterium, Dietzia and Turicella and the family Mycobacteriaceae the genera Gordona, Mycobacterium, Nocardia, Rhodococcus and Tsukamurella. It was clear from the 1 6S rDNA sequence data that Nocardia pinensis was misclassified in the genus Nocardia and that TsukamurelIa wratislaviensis belonged to the genus Rhodococcus. The genus Nocardia formed a distinct dade that was clearly associated with the genus Rhodococcus. Two sublines were recognised within the Nocardia dade; one consisted of Nocardia asteroides and related taxa and the other of Nocardia otitidiscaviarum and allied species. The two sublines are distinguished by nucleotide differences in helix 37-1. The type strains of all of the Nocardia species contained hexahydrogenated menaquinones with eight isoprene units in which the two end units were cyclised. Actinomycetes selectively isolated from an activated sludge plant showing extensive foaming were the subject of a polyphasic taxonomic study. The sludge isolates, which clearly belong to the genus Tsukamurella on the basis of 1 6S rRNA data, contained highly unsaturated long chain mycolic acids and unsaturated menaquinones with nine isoprene units, properties consistent with their classification in the genus Tsukamurella. Six representative isolates and marker strains of Tsukamurella paurometabola were the subject of a numerical phenetic taxonomic study. The test strains were assigned to four groups in the simple matching coefficient, unweighted pair group method with arithmetic averages analysis. The sludge isolates formed a homogeneous cluster with the three remaining clusters composed of Tsukamurella paurometabola strains. Excellent congruence was found between these numerical taxonomic data and results derived from corresponding studies based on Curie point pyrolysis mass spectrometric and whole-organism protein electrophoretic analyses. The combined data suggest that the sludge isolates form the nucleus of a new species of the genus Tsukamurella and that Tsukamure!!a paurometabola is a heterogeneous taxon. Representatives of three putatively novel streptomycete species isolated from soil were used to develop and evaluate an identification system based on Curie point pyrolysis mass spectromety and artificial neural network analysis. The test strains consisted of sixteen target Streptomyces strains and one hundred and thirty-eight actinomycetes belonging to the genera Actinomadura, Mycobacterium, Nocardia, Nocardiopsis, Saccharomonospora and Streptosporangium. It was clear from the identification results that artificial neural network analysis was superior to conventional procedure based on principal component and canonical variate statistics. The problem of misidentification of some of the non-target strains was solved by the development of a neural network topology which contained an output neuron designed to detect non-target pyrolysis mass spectrometric patterns. The pyrolysis mass spectrometry-artificial neural network system was evaluated using thirteen fresh streptomycete isolates and found to be capable of long-term identification of the target strains.
23

Polyphasic taxonomy of thermophilic actinomycetes

Kim, Bongcheol January 1999 (has links)
Molecular systematic methods were applied in a series of studies designed to resolve the taxonomic relationships of thermophilic actinomycetes known to be difficult to classify using standard taxonomic procedures. The test strains included representatives of clusters defined in an extensiven umerical phenetic survey of thermophilic streptomycetesa nd twelve marker strains. The resultant genotypic data together with the results of corresponding phenotypic studies were used to highlight novel taxa and to improve the circumscription of validly described species. The most comprehensive study was undertaken to clarify relationships within and between representative alkalitolerant, thermophilic and neutrophilic, thermophilic streptomycetes isolated from soil and appropriate marker strains. The resultant data, notably those from DNA: DNA relatedness studies, supported the taxonomic integrity of the validly described species Streptomyces thermodiastaticus, Streptomyces thermoviolaceus and Streptomyces thermovulgaris. However, the genotypic and phenotypic data clearly show that Streptomyces thermonitrificans Desai and Dhala 1967 and Streptomyces thermovulgaris (Henssen 1957) Goodfellow et al. 1987 represent a single species. On the basis of the priority, Streptomyces thermonitrificans is a later subjective synonym of Streptomyces thermovulgaris. Similarly, eight out of eleven representative alkalitolerant, thermophilic isolates and three out of sixteen representative neutrophilic, thermophilic isolates had a combination of properties consistent with their classification as Streptomyces thermovulgaris. One of the remaining alkalitolerant, thermophilic isolate, Streptomyces strain TA56, merited species status. The name Streptomyces thermoalcalitolerans sp. nov. is proposed for this strain. A neutrophilic, thermophilic isolate, Streptomyces strain NAR85, was identified as Streptomyces thermodiastaticus. Four other neutrophilic thermophilic isolates assigned to a numerical phenetic cluster and a thermophilic isolates from poultry faeces were also considered to warrant species status; the names Streptomyces eurythermophilus sp. nov. and Streptomyces thermocoprophilus sp. nov. are proposed to accommodate these strains. It was also concluded that additional comparative taxonomic studies are required to clarify the relationships between additional thermophilic streptomycete strains included in the present investigation. A corresponding polyphasic approach was used to clarify the taxonomy of six thermophilic isolates provisionally assigned to either the genera Amycolatopsis or Excellospora. Two of the isolates, strain NT202 and NT303, had properties consistent with their classification in the genus Amycolatopsis. However, the genotypic and phenotypic data also showed that these strains formed a new centre of taxonomic variation for which the name Amycolatopsis eurythermus sp. nov. is proposed. Similarly, the four remaining strains formed two new centre of taxonomic variation within the genus Excellospora. It is proposed that isolates TA113 and TA114 be designated Excellospora alcalithermophilus sp. nov. Similarly, the name Excellospora thermoalcalitolerans sp. nov. is proposed for strains TA86 and TA111. An emended description is also given for the genus Excellospora.
24

A systematic revision of the Cylindroleberididae (Crustacea: Ostracoda: Myodocopa)

Syme, Anna Unknown Date (has links) (PDF)
Ostracods of the family Cylindroleberididae are speciose, widespread, and well-defined by morphological features including the possession of gills. Despite the family having been divided into three subfamilies, five tribes, 32 genera, and more than 200 species, the relationships between its species have never been analysed phylogenetically. Twenty-five of the 32 genera are not defined by unique features but rather combinations of characters, and may therefore be historical constructions rather than evolutionary groups. The classification is of limited functional and predictive use, and requires a systematic revision. (For complete abstract open document)
25

Systematics of the Onychoteuthidae Gray, 1847 (Cephalopoda: Oegopsida)

Bolstad, Kathrin S. Unknown Date (has links)
Squids in the family Onychoteuthidae Gray, 1847 have been reported from every ocean but the Arctic, are taken frequently in deep-sea fisheries by catch, and are ecologically important in the diets of many marine predators including cetaceans, pinnipeds, sharks, and seabirds. However, the diversity and systematic of the family have remained poorly understood. Of the 60+ nominal species, 12–14 have generally been accepted in recent studies. Challenges to clarity include insufficient species descriptions, original descriptions published in eight languages and often based solely on early life stages, non-designation or subsequent loss of type material, and the existence of several unresolved species complexes. In light of the general systematic disarray of the Onychoteuthidae, a global revision of the family follows, based on ~1500 specimens examined from 19 repositories. Type material has been examined wherever possible; for some species, photographs of type specimens, original illustrations, and/or the original descriptions have provided the only information available. It has not been possible to fully disambiguate taxa in some cases (e.g. Gen. nov. 2), given the limited material and information available, but for all species treated in this revision (25 out of 26 species; no material was available for Kondakovia nigmatullini), descriptions and illustrations are provided to a consistent standard that will enable their reidentification. External and internal morphological characters and states are described for sub adult to adult stages of most species, with external characters reported through ontogeny as permitted by available material. Historically important characters are treated (general external morphology, body proportions, tentacle clubs, photophores, gladius, lower beak, radula), augmented by several more recently recognised characters (palatine teeth, detailed morphology of the tentacular hooks in adults, tentacular suckers in paralarvae, chromatophore patterns). The systematic value of both historical and new morphological characters at the generic and species levels are discussed; at all ontogenetic stages, tentacular club and hook morphology are considered the most valuable characters, although body proportions and gladius also prove useful. Partial disambiguation of the Onychoteuthis banksii complex has been possible in the Pacific and Atlantic Oceans, resulting in the resurrection of Onychoteuthis bergii Lichtenstein, 1818 and Onychoteuthis aequimanus Gabb, 1868, the description of two new species, Onychoteuthis lacrima and Onychoteuthis prolata (in press), and the expansion of one species’ recognised distribution (Onychoteuthis compacta) to include the Atlantic Ocean. The genus Moroteuthis Verrill, 1881 is considered a junior synonym of Onykia Lesueur, 1821, in accordance with the findings of several earlier authors. However, morphological differences in the species ‘Moroteuthis’ ingens necessitate the resurrection of the subgenus Moroteuthopsis Pfeffer, 1908b, with all other Onykia species placed into a new subgenus, Onykia (Onykia). Sexual dimorphism is reported in the beaks of Onykia (Moroteuthopsis) ingens (new comb.), and revised sex-specific equations are given for estimating this species’ biomass based on LRL. Morphological and historical genetic data suggest a more distant relationship between Onykia and the species ‘Moroteuthis’ knipovitchi Filippova, 1972 than was suggested by earlier classifications. This species is therefore considered to represent an undescribed genus, herein referred to as Gen. Nov. 1, which cannot be more fully diagnosed and described at present due to limited material. The generic position of ‘Onykia’ rancureli (Okutani, 1981) is also uncertain; it may be allied to Walvisteuthis virilis Nesis & Nikitina, 1986 (family Walvisteuthidae Nesis & Nikitina, 1986), but confirmation is impossible without examining type material of W. virilis. A second new genus, Gen. Nov. 2, is therefore described for ‘Onykia’ rancureli and several morphological variants reported from the Pacific and Atlantic Oceans. Given that the majority of available onychoteuthid material was collected after 1950, resulting in the descriptions of over half of the generally accepted genera and species since 1960, ongoing collection programmes are necessary to further resolve onychoteuthid systematic.
26

Sistemática da família Cassidulidae (Echinoidea: Cassiduloida) e considerações taxonômicas e paleobiogeográficas

Souto, Camila 03 September 2013 (has links)
Submitted by Johnsson Rodrigo (r.johnsson@gmail.com) on 2013-08-29T04:57:23Z No. of bitstreams: 1 CAMILA.pdf: 4295274 bytes, checksum: 3b6ba55df2f36928304a61d910553c85 (MD5) / Approved for entry into archive by Alda Lima da Silva(sivalda@ufba.br) on 2013-09-03T18:19:01Z (GMT) No. of bitstreams: 1 CAMILA.pdf: 4295274 bytes, checksum: 3b6ba55df2f36928304a61d910553c85 (MD5) / Made available in DSpace on 2013-09-03T18:19:01Z (GMT). No. of bitstreams: 1 CAMILA.pdf: 4295274 bytes, checksum: 3b6ba55df2f36928304a61d910553c85 (MD5) / FAPESB / Os cassidulóides têm proporcionado grandes desafios aos taxonomistas que tentam classificá-los, provavelmente por se tratar de um grupo artificial. Estudos filogenéticos da ‘ordem’ resultaram em topologias com baixa resolução devido à falta de informação acerca de alguns táxons e sinais de exaustão de caracteres ao longo da evolução de suas famílias. Dentre elas, a família Cassiulidae é composta por cinco a seis gêneros e pouco se sabe sobre o relacionamento entre seus gêneros, visto que análises ao nível de ordem incluíram poucas espécies desta família. Neste trabalho foram realizadas análises cladísticas para propor uma hipótese de relações filogenéticas entre os gêneros da família Cassidulidae. A análise principal incluiu 16 cassidulídeos e 33 caracteres morfológicos. As análises seguintes tiveram como objetivo verificar a influência dos dados faltantes e da inclusão de táxons fósseis na topologia encontrada. Cada uma das três análises resultou em uma única árvore mais parcimoniosa, em geral, bem resolvida. As relações de parentesco foram: (Eurhodia relicta (demais Eurhodia) + ((Australanthus + Cassidulus malayanus) + (Paralampas (Cassidulus + Rhyncholampas)))). Tanto a quantidade de dados faltantes quanto a exclusão de espécies fósseis não afetaram negativamente a resolução da árvore. Os resultados obtidos indicaram a necessidade de estudar a taxonomia, principalmente, dos gêneros Eurhodia, Cassidulus e Rhyncholampas e a exclusão de Cassidulus malayanus e Eurhodia relicta dos seus respectivos gêneros. Possíveis ocorrências de processos heterocrônicos foram detectadas, a exemplo da evolução do gênero Rhyncholampas por peramorfose e do gênero Paralampas por pedomorfose. Os cassidulídeos provavelmente se originaram no Cretáceo Tardio e novidades não foram adicionadas à sua evolução. Como resultado, processos heterocrônicos devem ter desempenhado um papel importante na diversificação da família. Evidências de processos heterocrônicos obtidas a partir da análise atual foram discutidas. Finalmente, um cenário paleobiogeográfico dos cassidulídeos foi proposto, com origem Tetiana e dispersão inicial, seguida por expansão e vicariância. / Salvador
27

Contributions to the systematics of the genus Schizochilus / Contributions to the systematics of the genus Schizochilus

MacRobert, M, MacRobert, M 27 February 2017 (has links)
The genus Schizochilus, first described by Sonder in 1847 as an extra-tropical Southern African orchid, is based upon material collected by Ecklon and Zeyher in moist places in the Winterberg mountains. The main characters of the flower are a spurred, fleshy three-cleft lip; and free, erect sepals and petals, all three sepals being equal and the petals much smaller than the sepals. The type species, S. zeyheri Sond., is described as having a small number (2-3) of linear-oblong basal leaves and a spike of 16-20 small flowers. Sepals and petals are both noted as white, the sepals about 0,5 cm in length (2.5 lines) and marked with 3 rosy veins, the petals lanceolate and half the length of the sepals. The spur is "not much shorter than the labellum" and the ovary, "almost twice the length of the spur". The lip itself, obovate in outline, is covered with very small crystalline papillae, the lateral lobes being "somewhat shorter than title broader, obtuse intermediate lobe". There appears to be no mention of the basal tubercles or calli on the lip.
28

Fire regime and tree/shrub/grass balance at Pretoriuskop in the Kruger National Park: Evidence from ground photographs

Ntsohi, Refiloe 13 February 2017 (has links)
No description available.
29

Taxonomy, phylogeny and biogeography of francolins ('Francolinus' spp.) Aves: Order Galliformes, Family Phasianidae

Mandiwana-Neudani, Tshifhiwa Gift January 2014 (has links)
Includes bibliographical references. / Francolins (Francolinus spp.) are small to medium-sized, sedentary, Old World, partridge/quail-like, terrestrial gamebirds (Order Galliformes) that occupy diverse habitats ranging from dry/open/scrubby lowland and montane grasslands, bushveld and savanna/woodland to mesic montane/lowland forests and forest edges. Some francolins have complex distribution patterns and also are morphologically, ecologically and behaviourally diverse. At the start of this research, Francolinus Stephens, 1819 was considered a monophyletic galliform genus comprising 41 species (36 African and five Asiatic) divided among eight putatively monophyletic species groups and four taxonomically enigmatic species. However, different taxonomic revisions, especially post Hall's (1963) classic monograph, challenged the monophyletic status of the genus and that of some of its designated species groups differed markedly in the number of recognized subspecies. Furthermore, there was debate concerning the geographical origin of the genus: Asia versus Africa. Some of the early molecular research on a few exemplar francolin species based on partial mitochondrial Cytochrome-b DNA sequences and Restriction Fragment Length Polymorphisms (RFLPs) also challenged the monophyly of the genus and that of some of Hall's (1963) species groups. These findings suggested that francolins may form at least two distantly related lineages called 'patryse' (partridges) and 'fisante' (pheasants) by Afrikaans-speaking people. Patryse, or 'true' francolins, had been divided into as many as five genera (Francolinus, Ortygornis, Dendroperdix, Peliperdix, Scleroptila) and fisante, or spurfowls, all grouped into a single genus, Pternistis. Research in this thesis is based on: mitochondrial and nuclear DNA sequences (5554 base pairs), organismal and vocal characters of francolins and spurfowls.
30

Do Savanna acacias nodulate as seedlings?

Szoke, Tim 07 February 2017 (has links)
No description available.

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