THE PROSPECT OF BIOGAS AMONG SMALL-HOLDER DAIRY GOAT FARMERS IN THE ULUGURU MOUNTAINS, TANZANIA

Biogas can be a clean cooking alternative where biomass is the dominant source of cooking energy and where feedstock for anaerobic digestion is available. By substituting woody biomass for energy, biogas may reduce local deforestation. Tanzania has more than 15.6 million goats. Dairy goats of different breeds are found in the mid- to high altitudes of the country. Population density has made firewood increasingly scarce and there are few energy alternatives in mountainous areas such as in the Uluguru Mountains. In Mgeta ward, Morogoro region, introduction of Norwegian dairy goats in the 1980s has improved livelihoods in the area. In this study, goat manure was assessed as feedstock for biogas and as fertilizer. Field work among small-holder dairy goat farmers in Mgeta was conducted to measure daily manure production, and to provide a basic model for prediction of the quantity of droppings which may be collected by farmers. Biogas and fertilizer potential from goat manure was compared to cow and pig manure. Buswell’s formula was used to calculate approximate methane yield. The results show that goat manure from Mgeta can yield 167 l∙kg Volatile Solids-1 (VS). Compared with other substrates approximate methane yield can be ranked as pig > guatemala grass > cow > goat. The average goat of 25 kg in Mgeta leaves 61 kg Total Solids (TS) droppings per year. It was estimated that 15 goats capita-1 would be required to meet the total cooking energy needs of small-holder households in the study location. N:P:K content in goat manure (TS) is 2:1:1, similar to cow and pig manure. Goat droppings had to be macerated to reduce particle size for anaerobic digestion. Biogas from dairy goats could be combined with the year-round irrigated horticulture production in Mgeta. Vegetable gardens in the slope below the digesters could be fertilized by gravitation with the NH4+-rich bioslurry, to save labour and increase yields.

Triptolide induces cell apoptosis in human stomach cancer cell via caspase 3-dependent cascade pathway

Purpose: To evaluate the effect of triptolide on the induction of cell apoptosis in human gastric cancer BGC-823 cells. Methods: The cytotoxicity of triptolide was evaluated by 3-(4, 5-dimethylthiazol-2-yl)-2, 5- diphenyltetrazolium bromide (MTT) assay. The effect of triptolide on cell proliferation was measured using lactate dehydrogenase (LDH) assay. Cell apoptosis was determined by Annexin V/propidium iodide (PI) double-staining assay. Results: MTT results indicate that triptolide significantly decreased cancer cell numbers in dose- and time-dependent manners in MTT assay. Data from LDH assay showed that triptolide markedly induced cytotoxicity in gastric cancer cells. Triptolide also remarkably induced both early and late apoptotic process in BGC-823 cells. In addition, the compound down-regulated the expression of anti-apoptotic Bcell lymphoma-2 (bcl-2) and up-regulated the expression of pro-apoptotic BCL-2-associated X (bax) in a dose-dependent manner. Furthermore, the pro-apoptotic activity of triptolide was involved in the activation of caspase-3 pathway in BGC-823 cells. Conclusion: Taken together, the findings strongly indicates that the pro-apoptotic activity of triptolide is regulated by caspase 3-dependent cascade pathway, and thus needs to be further developed for cancer therapy.