Browsing by Subject "Regeneration"

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The baobab (Adansonia digitata L.) in Southern Kenya–a study on status, distribution, use and importance in Taita–Taveta County
(2020) Fischer, Sahrah; Jäckering, Lisa; Kehlenbeck, Katja
Baobab (Adansonia digitata L.) is a multipurpose, drought resistant, wild fruit tree, endemic to arid and semi-arid lands of Sub-Saharan Africa. Baobab populations have been showing a lack of regeneration, and therefore causes concern for the species survival. This study investigated the state, distribution and use of baobabs in an under-researched population in Kenya, to identify the potential for further use and development of baobab resources. A baobab population was chosen in Taita–Taveta County, covering a sample area of 2015 km2. A systematic stratified transect survey was done to map baobab distribution using 49 transects (0.5 × 3 km each). The diameter at breast height and other indicators were measured on all baobabs in the transects to assess population status and health. A household survey (n = 46) and focus group discussions (n = 12) were done following the transect survey to gain an idea on the uses and distribution of baobab. In total, 432 baobab trees were measured and recorded in the research area of 2015 km2. The baobabs grew in two clusters (i.e., areas with a baobab density of ≥0.08 baobabs/ha). Both clusters showed rejuvenating populations. The main factors identified by the respondents, positively and negatively influencing baobab distribution were environmental factors, wildlife, human impact and commercial value. The study area shows a great potential for baobab to become an important part of the diet, due to its current use as an emergency food during food scarce times, and the relatively healthy and stable rejuvenating populations.
Entwicklung und Charakterisierung des rekombinanten, bifunktionalen Proteins SDF1-GPVI und dessen Einfluss auf die myokardialen Reparaturmechanismen
(2012) Ziegler, Melanie; Graeve, Lutz
Cardiovascular diseases like myocardial infarction, arteriosclerosis and coronary heart disease are the leading cause of death worldwide. Because of this, development of novel and innovative biopharmaceutical approaches is very important to improve the therapy of cardiovascular diseases. Especially after myocardial infarction, promoting cardiac repair mechanisms is of vital importance to preserve cardiac function and decrease scar size. The chemokine ?stromal cell-dervied factor-1? (SDF-1) plays a crucial role in stem cell homing and is upregulated after myocardial infarction. It is already known that the SDF-1/ CXCR4 axis promotes myocardial repair. In this study we connected SDF-1 with an anchor structure to accumulate this chemokine specifically at the infarcted myocardium. The anchor structure consists of the soluble glycoprotein VI (GPVI). GPVI is the major collagen receptor on platelets and binds to nearly all collagen types and other proteins of the extracellular matrix like fibronectin and vitronectin. Hence, SDF1-GPVI specifically accumulates at the injured tissue and attracts progenitor cells from the blood stream to the lesion site. During the course of this study, the recominant, bifunctional protein SDF1-GPVI, consisting of human SDF-1 and soluble human GPVI, was generated. Subsequently, the functional efficacy of the SDF-1 and GPVI domains were proven by several functional assays and the bifunctionality of SDF1-GPVI was determined by dynamic adhesion in a flow chamber system. Further, in vitro studies showed that SDF1-GPVI triggers chemotaxis of haematopoetic progenitor cells (HPCs), enhances and accelerates endothelial differentiation of HPCs and preserves survival of HPCs. Furthermore, using the ?Chorioallantoic Membrane? (CAM) assay SDF1-GPVI revealed proangiogenic effects in ovo. Prior to in vivo analysis, a pharmacokinetic study showed that SDF1-GPVI has a biological half-life >48 h. After induction of myocardial infarction, treatment with SDF1-GPVI and G-CSF lead to a significantly decrease in infarct size and to a significantly preserved myocardial function 28 days after transient ischemia/reperfusion. Additional positive effects were enhanced homing of GFP-labelled ?bone marrow cells? (BMCs), increased recruitment of CXCR4-positive cells and enhanced neovascularisation in the infarcted myocardium. Therefore, the bifunctional protein SDF1-GPVI bears the potential to serve as a promising biopharmaceutical therapeutic to promote myocardial repair especially after myocardial infarction.