Micromorphological structure of the fruit and seed of Smodingium argutum (Anacardiaceae), as an adaptation to its natural habitat

Smodingium argutum E. Mey. ex Sond, is very closely allied lo the genus Rhus L., but easily distinguished from it by the inflorescence which is a thyrse, ils pendulous ovule; an ‘apical-lateral’ style; winged fruit; a sap (noxious secretion from all organs) which turns black on exposure to air; indumentum on the pedicel, bracteoles and calyx, as well as an unique, papery pericarp. The latter comprises a uniseriate exocarp a mesocarp with large secretory ducts and a mostly two-layered, weakly developed endocarp. An anatropous, bitegmic, crassinucellate ovule develops into a small, partially pachychalazal, exalbuminous seed, also characterized by an endotegmen and lipidie nutrient reserves. The following characters are obviously of crucial importance for the survival of this species, efficient fruit dispersal, aided by the samaroid drupe; easy germination; the well-developed cuticles on the calyx, ovary wall and exocarp; and the thick cuticular layer delimiting the mature integumentary seed coat, which, together with cell wall impregnations in the physiologically mature hypostase cells, protects the embryo against dehydration

Taxonomic position of Rhus problematodes (Anacardiaceae): Evidence from fruit and seed structure

This is the first report on the structure of the pericarp and seed coat of Rhus problematodes Merxm. & Roessl., a curious microphyllous shrublet of very limited distribution in the southern desert region of Namibia. Mainly on the basis of macromorphology, it was hitherto considered to stand somewhat apart from other African members of Rhus L. (sect. Gerontogeae Engl.). R. problematodes clearly agrees with other species of Rhus in its basic pericarp and seed-coat characteristics, including a single-seeded unilocular drupaceous fruit, parenchymatous mesocarp with secretory ducts, ridged outer endocarp, inner endocarp composed of three discrete layers, and an endotegmic, partially pachychalazal seed coat. The scarcity of stomata and heavy deposition of cutin in the exocarp possibly reflect adaptations to its arid habitat. Evidence from fruit and seed structure, combined with that from other sources, reconfirms the view that it is a highly specialized species of Rhus showing several xeromorphic, mainly macromorphological, reductions. The shared presence of glandular stellate hairs and reduced foliage leaves suggests that it might be closely allied to R. horrida Eckl. & Zeyh., a species from Namaqualand

A preliminary study on the germination of Sclerocarya birrea subsp. caffra

Seeds of Sclerocarya birrea (A. Rich.) Hochst. subsp. caffra (Sond.) Kokwaro, commonly known as marula, occur in locules within a hard lignified endocarp. The endocarp appears to restrict germination mainly by offering mechanical resistance. It may also restrict the leaching of germination inhibitors and possibly serve as a barrier to oxygen diffusion. The endocarp does not restrict water uptake. High germination counts were only obtained by removing opercula. Leaching slightly improved germination of seeds in intact endocarps. The optimum germination temperature of opercula-removed seeds was between 27° and 37°C. Storage improved rate of germination

The structure of the seed of Mangifera indica L. and notes on seed characters of the tribe Mangifereae (Anacardiaceae)

The anatropous, unitegmic and pachychalazal mango ovule develops into the campylotropous, pachychalazal seed. The undifferentiated seed coat is of dual origin, developing from the integument as well as from the pachychalaza. The term ‘peritesta’ is suggested for the peripheral, band-like integumentary part of the seed coat. The major saddle-shaped chalazal part is associated with a tanniniferous hypostase. The discussion includes the anatomy and histochemistry of the seed. The pachychalazal seed with undifferentiated seed coat probably characterizes the tribe Mangifereae. After consideration inter alia of seed characters, it is concluded that, according to generally accepted criteria, the Anacardiaceae is phylogenetically one of the more advanced forest families

A morphological study of the fruit and seed of certain southern African members of the Anacardiaceae

The Anacardiaceae is a natural family which is grouped into five tribes. Two of these occur in southern Africa. The Spondieae is represented by Harpephyllum Bernh. ex Krauss, Lannea A. Rich. and Sclerocarya Hochst. and the Rhoideae by Heeria Meisn., Laurophyllous Thunb., Loxostylis Spreng. f. ex Reichb., Ozoroa Del., Protorhus Engl., Rhus L. and Smodingium E. Mey. ex Sond. Although this study focusses mainly on the three species of the Spondieae and Rhus lancea L.f., observations on other species, e.g. of Heeria, Mangifera L., Operculicarya H. Perr. and Tapirira Aubl., are also described. The thesis includes reprints and manuscripts of scientific papers, dealing mainly with the ontogeny and structure of the fruit and seed. The taxonomic significance of characters is stressed, supplemented with notes on evolutionary trends and seed germination. A comprehensive review of the literature is provided, including comments on the structure and function of the hypostase and occurrence of the pachychalaza. The exocarp of the drupe in Anacardiaceae may be thin (R. lancea) or thick, representing an exocarp sensu lato (Sclerocarya). The mesocarp is characterized by conspicuous secretory ducts and usually differentiates after endocarp lignification. The endocarp is usually a sclerocarp. It is either stratified (R. lancea) or non-stratified (Spondieae). Opercula are restricted to the members of the Spondieae with well-developed sclerocarp.Thesis (DSc)--University of Pretoria, 1988.Plant ScienceDScUnrestricte

Whole genome and transcriptome amplification: practicable tools for sustainable tissue biobanking?

The use of whole genome amplification (WGA) and whole transcriptome amplification (WTA) techniques enables the enrichment of DNA and RNA from very small amounts of tissue. Here, we tested the suitability of WGA and WTA for tumor tissue biobanking. DNA and RNA from 13 standardized and seven non-standardized frozen and 12 formalin-fixed, paraffin-embedded (FFPE) clear cell renal cell carcinoma specimens (>9years old) served to test the robustness of the WGA and WTA products by reidentifying von Hippel-Lindau (VHL) gene mutations known to exist in these samples. The enrichment of DNA and RNA from frozen tissue was up to 1,291-fold and 423-fold, respectively. The sizes and yields (10- to 73-fold) of the amplified DNA obtained from the 12 FFPE samples were generally lower. The quality of the RNA from the FFPE samples was too low to reliably perform WTA. Our results demonstrate that frozen tumor tissue is very suitable for WGA and WTA. All 20 VHL mutations were verified with WGA. Notably, we were able to show that 18 of the 20 (90%) VHL mutations are also transcribed. In FFPE tumor tissue, 8 of 12 cases (67%) showed the expected mutations after the first WGA. Accurate WTA with FFPE material is sophisticated and strongly depends on the modification and degradation status of the fixed tissue. We conclude that for sustainable tissue biobanking, the use of WGA and WTA is a unique opportunity to provide researchers with sufficient amounts of nucleic acids, preferably from limited frozen tissue materia

Widespread Reassortment Contributes to Antigenic Shift in Bluetongue Viruses from South Africa

Bluetongue (BT), a viral disease of ruminants, is endemic throughout South Africa, where outbreaks of different serotypes occur. The predominant serotypes can differ annually due to herd immunity provided by annual vaccinations using a live attenuated vaccine (LAV). This has led to both wild-type and vaccine strains co-circulating in the field, potentially leading to novel viral strains due to reassortment and recombination. Little is known about the molecular evolution of the virus in the field in South Africa. The purpose of this study was to investigate the genetic diversity of field strains of BTV in South Africa and to provide an initial assessment of the evolutionary processes shaping BTV genetic diversity in the field. Complete genomes of 35 field viruses belonging to 11 serotypes, collected from different regions of the country between 2011 and 2017, were sequenced. The sequences were phylogenetically analysed in relation to all the BTV sequences available from GenBank, including the LAVs and reference strains, resulting in the analyses and reassortment detection of 305 BTVs. Phylogenomic analysis indicated a geographical selection of the genome segments, irrespective of the serotype. Based on the initial assessment of the current genomic clades that circulate in South Africa, the selection for specific clades is prevalent in directing genome segment reassortment, which seems to exclude the vaccine strains and in multiple cases involves Segment-2 resulting in antigenic shift

Next Generation Sequencing of Reactive Stroma and Residual Breast Cancer Cells in Tumor Bed after Neoadjuvant Chemotherapy

Primary systemic or neoadjuvant chemotherapy of breast cancer has become a standard therapy option in locally advanced or predefined intrinsic subtypes such as triple negative or Her2 positive breast cancer. Neoadjuvant chemotherapy can result in complete pathological response without residual tumor cells (tumor bed) or partial response and non-response with different amounts of reactive stroma and residual tumor cells. The interaction between therapy regimens and tumoral driver mutations have been extensively studied, although the reactive stroma of the tumor bed received less attention. In this study, we characterized the mutational status of residual breast cancer cells and reactive tumor stroma devoid of residual tumor cells in partial or non-responders using next generation sequencing. Twenty-one post-therapeutic breast surgical specimens after neoadjuvant chemotherapy underwent pathogenic driver-mutation screening using microdissected residual breast cancer cells and in reactive stroma adjacent to tumor bed areas. In reactive stroma, no mutations could be validated. In residual breast cancer cells, mutations were detected in sixteen of twenty-one cases (76%). In nine of these twenty-one cases (43%), pathogenic driver mutations (PIK3CA, PTEN, TP53, FN1, PLAG1) were identified. Pathogenic driver-mutations are exclusively restricted to residual carcinoma cells and are absent in reactive stroma independently from intrinsic breast cancer subtypes or tumor stage. These data suggest that the absence of pathogenic mutations in a tumor bed without residual tumor cells may have prognostic implications after neoadjuvant chemotherapy

Von-Hippel-Lindau-Gen-Mutationstypen: Assoziation mit Genexpressionssignaturen in klarzelligen Nierenzellkarzinomen

Zusammenfassung: Fragestellung: Der Von-Hippel-Lindau- (VHL-)Tumorsuppressor ist ein multifunktionelles Protein. VHL-Mutationen treten häufig auf im klarzelligen Nierenzellkarzinom (kNZK). Verschiedene Mutationstypen führen vermutlich zu spezifischen pVHL-Funktionsveränderungen, die wiederum einen signifikanten Einfluss auf die Genexpression und schließlich auf den Krankheitsverlauf haben dürften. Ziel der vorliegenden Studie ist die Korrelation von Genexpressionssignaturen mit spezifischen VHL-Mutationstypen im kNZK. Methodik: Transkriptomanalyse wurde für 94 kNZK und 21 papilläre NZK (pNZK) mittels Affymetrix HG U133A Genchips durchgeführt. Alle 94 kNZK wurden auf VHL-Mutationen analysiert. Ergebnisse: Ein "hierarchical clustering" anhand der zwischen kNZK und pNZK differenziell regulierten Gene zeigt eine deutliche Stratifizierung der beiden histologischen Subtypen. 186 Gene wurden zwischen VHL-Wildtyp kNZK und kNZK mit mutiertem VHL-Gen differenziell exprimiert. Schlussfolgerung: Unsere Resultate weisen auf eine signifikante Auswirkung von VHL-Mutationen auf die Genexpression im NZK hi

Whole genome and transcriptome amplification: practicable tools for sustainable tissue biobanking?

The use of whole genome amplification (WGA) and whole transcriptome amplification (WTA) techniques enables the enrichment of DNA and RNA from very small amounts of tissue. Here, we tested the suitability of WGA and WTA for tumor tissue biobanking. DNA and RNA from 13 standardized and seven non-standardized frozen and 12 formalin-fixed, paraffin-embedded (FFPE) clear cell renal cell carcinoma specimens (>9 years old) served to test the robustness of the WGA and WTA products by reidentifying von Hippel-Lindau (VHL) gene mutations known to exist in these samples. The enrichment of DNA and RNA from frozen tissue was up to 1,291-fold and 423-fold, respectively. The sizes and yields (10- to 73-fold) of the amplified DNA obtained from the 12 FFPE samples were generally lower. The quality of the RNA from the FFPE samples was too low to reliably perform WTA. Our results demonstrate that frozen tumor tissue is very suitable for WGA and WTA. All 20 VHL mutations were verified with WGA. Notably, we were able to show that 18 of the 20 (90 %) VHL mutations are also transcribed. In FFPE tumor tissue, 8 of 12 cases (67 %) showed the expected mutations after the first WGA. Accurate WTA with FFPE material is sophisticated and strongly depends on the modification and degradation status of the fixed tissue. We conclude that for sustainable tissue biobanking, the use of WGA and WTA is a unique opportunity to provide researchers with sufficient amounts of nucleic acids, preferably from limited frozen tissue material