Microbiology and Parasitology

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A note on the fate of tetrasporangial stichidia in Hypnea Lamouroux after spore release
(Botanica Marina, 1976) Mshigeni, Keto E.
The fate of the tetrasporangial Stichidia has been investigated in Hypnea cervicornis and H. chordacea. It was foundthat Stichidia are not determinate branchJets äs was once thought, but continue with vegetative giowth after sporeshedding, Even where the Stichidia became detached from the main axes after spore shedding, they developed newholdfasts and grew into new thalli.
Seaweed farming: a possibility for Tanzania's coastal Ujamaa villages
(Tanzania Notes and Records, 1976) Mshigeni, Keto E.
Tanzania is fortunate in having a relatively long shoreline and many offshore islands which support appreciable quantities of seaweeds. One of the most notable seaweeds is the genus Eucheuma which has been harvested from the shores of Zanzibar, Pemba and Mafia Islands for over two decades. About 500 to 800 tons of dry Eucheuma are exported from Tanzania to Western Europe annually. The cells of this seaweed contain the industrial phycocolloid carrageenan, which has a wide range of applications in food, pharmaceutical and textile industries. It is likely that Eucheuma farming is a possible economic activity in Tanzania. In order to teach the farming techniques efficiently, it would seem desirable to establish the farms in some selected Ujamaa villages along the coast where the people to be recruited can be selected from amongst those already experienced with marine life, such as fishermen or shell-collectors.
Holdfast and Shoot Differentiation in the Sporelings of Hypnea cervicornis J. Agardh (Rhodophyta, Gigartinales)
(Botanica Marina, 1976) Mshigeni, Keto E.
Holdfast and shoot differentiation in the Sporelings of Hypnea cervicornis J. Agardh has been investigated for the first time. It was observed that the holdfasts of this species are not simple unicellular structures but consist of large masses of cells differentiated from amongst the superficial cells at the points of contact with the substratum. After or during holdfast differentiation, the morula-like mass of cells produced shoot Initials. One to four Initials were ob-served. When three or more initials were differentiated at the same time, stellate stages were formed. The stellate stages in Hypnea ontogeny are discussed with reference to similai structures reported in taxonomic literature äs diagnostic criteria for H. cornuta (Lamour.) J. Agardh
Field Cultivation of Hypnea (Rhodophyta) Spores for Carrageenan: Prospects and Problems
(Botanica Marina, 1976) Mshigeni, Keto E.
Carpospores and tetraspores ofHypnea cervicornis J, Agardh have been cultivated in the fieid. These developed intoadult fronds in thiee months. This implies that where nutrients or other environmental factors are not limiting, it ispossible to raise four harvestable crops of Hypnea from spores per year, Since carpospores gave rise to tetrasporo-phytes and tetraspores produced gametophytes, it was concluded that the life history of the species is of the Poly-siphonia-type
Effects of the environment on developmental rates of sporelings of two Hypnea species (Rhodophyta: Gigartinales)
(Marine Biology, 1976) Mshigeni, Keto E.
Growth of sporelings of Hypnea cervicornis J. Agardh and H. chordacea Kuetzing in response to gradients of selected environmental factors has been investigated. The sporelings of H. cervicornis tolerated higher levels of the tested parameters (e.g. salinity and temperature) than those of H. chordacea. In all the treatments, the sporelings of H. cervicornis grew significantly faster than those of H. chordacea. The ecological and agronomic implications of these findings are discussed.
On the ultrastructure of the cell wall and pit plugs of Chondrococcus hornemannii (Rhodophyta, Cryptonemiales)
(Botanica Marina, 1977) Mshigeni, Keto E.
The Ultrastructure of the cell wall of Chondrococcus hornemannii is being reported for the first time. Amongst the notable features revealed in this study are: the stratified appearance of the wall, the presence of distinct lenticular pit plugs where the wall is interrupted by pit connections, and the presence of floridean starch grains scattered in the cytoplasm.
Studies on the yield and infrared spectra of Phycocolloids from Chondrococcus hornemannii (Lyngbye) Schmitz and Sarconema filiforme (Sonder) Kylin from Tanzania
(De Gruyter, 1977) Mshigeni, Keto E.
Phycocolloids from Chondrococcus hornemannü and Sarconema filiforme have been investigated and found to be cairageenans. Yields of 45.1 ±0.1 and 35.7 ± 2.8% (of the dry weight) were obtained in the two species, respectively. The phycocolloid from S. filiforme showed a total sulphate of 18.3 ± 0.5% and IR absorption peaks characteristic of i-carrageenan. That of C hornemannü showed a sulphate content of 24.7 ± 0.3% and IR spectra and solubility properties akin to those of y-carrageenan. The economic potential of the seaweeds is discussed.
Studies on Carrageenans from the economic Red Algal Genus Eucheuma in Tanzania
(De Gruyter, 1977) Mshigeni, Keto E.
Carrageenan yields of five Tanzanian species of Eucheuma have been determined. The tnean yields obtained were 72.8%,69.0%, 65.0%, 58,0% and 54.0% for E. spinosum J. Agardh, E. striatum Schmilz, E. platycladum Schmitz, E. okamurai Yamada and E. speciosum J. Agardh f mauritianum Boergesen, respectively. Infrared spectroscopy studies were also con-ducted. E. striatum and E. okamurai showed absorption peaks characteristic öl -carrageenan; E. spinosum showed peaks characteristic of t-carrageenan. E. speciosum f. mauritianum and E. platydadum showed peaks more closely resemhling those of i- than -carrageenan.
Contributions on the content and nature of the Phycocolloid from Halymenia venusta Boergesen (Rhodophyta, Cryptonemiales)
(Botanica Marina, 1977) Mshigeni, Keto E.
The phycocolloid from Halymenia venusta Boergesen has been studied and found to be a carrageenan which is morecloscly related to y-than k-carrageenan. A total phycocolloid yield of 59.0 ± 2.5 % on dry weight basis was obtained.The presence of a cold water-soluble phycocolloid in the thaüi of H. venusta was also discovered and its IR spectrum determined.
Seasonal Changes in the Standing Crops of Three Hypnea Species (Rhodophyta: Gigartinales) in Hawaii
(Botanica Marina, 1977) Mshigeni, Keto E.
Studies have been conducted on Standing crops of Hypnea cervicornis J. Agardh, H. chordacea Kützing and H. nidifica J. Agardh in Hawaii. AH the three species showed Standing crop seasonality. The standing crops rcachedtheür maxima during winter (November to Januaiy). From January to May they showed a steady decline. The relationship between standing crops and seasonal changes in tidal behaviour is discussed.
Contributions on the Content and Nature of the Phycocoiloid from Laurencia papillosa (Forssk.) Greville (Rhodophyta, Ceramiales)
(Botanica Marina, 1977) Mshigeni, Keto E.
The content, infrared spectroscopy, total sulphate and optical rotation of the phycocolloid from Laurencia papillosa (Forssk.) Grevüle from Tanzania have been investigated. A phycocolloid yield of 33.6 ± 0-6% was obtained on a dry weight basis. The total sulphate content of the phycocolloid was 16.8 ± 0.4% and the optical rotation was found to be negative [a|D5 - 5.5 °. The phycocolloid was soluble in potassium Chloride. Its IR spectra showed absorptionpeaks more akin to -than -or -cairageenan. A detailed discussion of these findings is presented.
Spore germination and early stages of development in Hypnea musciformis (Rhodophyta, Gigartinales)
(Marine Biology, 1977) Mshigeni, Keto E.
The early stages of development of the carpospores and tetraspores of Hypnea muscilormis (Wulfen) Lamouroux have been investigated. Both types of spores germinated immediately after liberation. The spores segmented repeatedly into, 2, 3, 4 cells, etc. until a multicellular ball of cells was produced. The germination pattern was thus of the discal type, i.e., Typus discalis mediatus (Inoh, 1947) or the “Dumontia-type” in the terminology of Chemin (1937). Subsequently, a relatively expansive attachment holdfast was produced from each sporeling. This was followed by the development of up to 4 or more shoot axes arising from the basal disc. These findings are discussed with reference to an earlier study by the senior author on the developmental biology of other species of Hypnea Lamouroux.
The morphology and distribution ecology of Corynomorpha prismatica: A red seaweed of potential economic significance in southeast Tanzania
(Marine Biology, 1977) Mshigeni, Keto E.
Investigations have been conducted on the gross morphology and distribution ecology of Corynomorpha prismatica J. Agardh (Rhodophyta, Cryptonemiales) at Lindi, southeast Tanzania. The mean standing crop of the seaweed in the study locality was 518±80.2 g/m2 dry weight. Frond height varied as a function of habitat elevation, being 21.2±1.3, 20.2±2.0, 13.7±2.5 and 4.3±0.4 cm at-15, 5, 25 and 45 cm elevation above spring-tide low-water mark, respectively. Populations of C. prismatica were almost exclusively confined to west-facing vertical rocky surfaces sheltered from direct insolation during the morning hours. The fronds showed a wider variety of morphological appearance than reported in the literature. This was partly due to variations in the patterns of thallus regeneration after wounding. The economic implications of these findings are discussed.
Contributions to the Embryology of Padina gymnospora (Phaeophyta, Dictyotales)
(Botanica Marina, 1978) Mshigeni, Keto E.
Abstract The pattern of tetraspore germination and early stages of development in Padina gymnospora (Kuetzing) Vickers (Phaeophyta, Dictyotales) have been investigated for a period of seven weeks. The early stages of development were äs earlier reported for other Dictyotales. However, new findings were found with respect to shoot differentiation. The erect shoots were initiated both from the meristematic activity of the ‘Central nodule' and from shoot initials which developed at intervals along the length of the rhizoids. The biological significance of the rhizoidal shoots is discussed
Field Observations on the Colonization of New Substrata and Denuded Intertidal Surfaces by Benthic Macrophytic Algae
(Botanica Marina, 1978) Mshigeni, Keto E.
Investigations have been conducted on the colonization of new substrata (brick surfaces) and recolonization of denudedintertidal surfaces by frondose benthic algae on the tropical shores of Hawaii. Size measurements of the benthic algaecolonizing the habitats are presented and agronomic implications of the research findings are discussed
Studies on Spore Germination and Early Development in Stoechospermum marginatum (C Ag ) Kütz. (Phaeophyta, Dictyotales)
(Botanica Marina, 1979) Mshigeni, Keto E.
Abstract Investigations were conducted on the germination of tetraspores of the intertidal seaweed Stoechospermummarginatum (C. Ag.) Kutz. The influence of light on the polarity of the spores was also studied, and preliminarystudies were carried out on the response of the germlings to different salinities. A wide range in tetraspore size was observed. After the first cell division one cell developed into a rhizoid, and the other into a mass of cells, the central nodule, from which a primary shoot with a single apical cell arose. This shoot developed into a broad and flat structure, which subsequently branched dichotomously. Secondary shoots were formed in two ways: from the central nodule and from the primary rhizoid. The spores showed light induced polarity. Very high and very low salinities were not tolerated.
Solieria jaasundii, a new species of red algae (Gigartinales, Solieriaceae) from Tanzania
(Solieria jaasundii, a New Species of Red Algae (Gigartinales, Solieriaceae) from Tanzania, 1981) Mshigeni, Keto E.
An anatomical study of a marine red alga from Tanzania, which was previously identified as Rhabdonia Africana Jaasund, has shown the alga to be a new species of Solieria. Its thallus has a segmented construction, with regular constrictions along the axes, and its branches arise mainly at the constrictions. Internally the thallus shows a central, loosely-packed mass of medullary filaments, which are joined to one another by interconnecting strands like those known to occur in some members of the Solieriaceae, e. g., Solieria robusta. External to the medulla is a cortex composed of cells that are shorter but wider in diameter. The cortical cells progressively decrease in size outwardly. Stellate cells whose arms serve as interconnecting points between the cortex and the medulla are common. Thecortical cells contain numerous coiled, ribbon-like structures similar to those in Rhabdonia verticillata (Min-Theinand Womersley 1976). These are interpreted as chromatophores. The anatomy of the central part of the medulla and of the thallus apices shows the plant to be multiaxial in construction. A discussion of the findings is presented, and a new name for the alga, Solieria jaasundii sp. nov., is proposed
Coelarthrum boergesenii (Rhodophycophyta, Rhodymeniales): a new record from Tanzania
(Botanica Marina, 1981) Mshigeni, Keto E.
A study has been conducted on specimens of a marine red alga collected by G. F. Papenfuss and R. F. Scagel in Tanzania during the International Indian Ocean Expedition in 1962. The thallus of the alga is small (2-3 cm tall), with a segmented construction and constrictions along the axes. Its branches arise mainly on the segments, and these often anastomose making it difficult to separate individual axes. Anatomically the axes have an epidermal layer ofsmall cells (3—5 μιη in diameter) and a cortex with outer smaller (8—20 μτη in diameter) and inner larger (70—150 μπ\in diameter) cells. Some of the inner cortical cells bear deeply staining gland cells, which are 9—12 μιη in diameter. The alga was identified as Coelarthrum boergesenii Weber-van Bosse, and is here reported as a first record of the genus in Tanzania.
Inventory of plants used in traditional medicine in Tanzania. I. Plants of the families acanthaceae-cucurbitaceae
(Journal of ethnopharmacology, 1982) Mshigeni, Keto E.
Sixty-two plants are listed, which are used by traditional healers in the northeastern part of Tanzania. For each species are given: the botanical name with synonyms, vernacular name, collection number, locality, habitus, approximate distribution, and medical use. Results of a literature survey are also reported, including medical use, isolated constituents and pharmacological effects
Revision of the Red Algal Genus Galaxaura with Special Reference to the Species Occurring in the Western Indian Ocean
(Botanica marina, 1982) Mshigeni, Keto E.
A study of Galaxaura (Nemaliales, Chaetangiaceae) from Hast Africa (especially Tanzania, Mozambique, South Africa and Malagasy Republic) and Mauritius has revealed that the following nine taxa are represented: G. diesingiana Zanardini, G. fasciculata Kjellman, G. lapidescens (Ellis et Solander) Lamouroux, G. lenta Kjellman, G. margifiata (Ellis et Solander) Lamouroux, G, oblongata (Ellis et Solander) Lamouroux, G. obtusata (Ellis et Solander) Lamouroux, G. rugosa (Ellis et Solander) Lamouroux and G, subverticillata Kjellman. The species recognized include seven of the 62 treated by Kjeilman in 1900 and two species not treated by him. The nine species encompass 38 species reported by various authors for the region. A key to the species, comments on their morphology, illustrations of their growth habit and structure, and discussions of their taxonomy and nomenclature are presented.

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