71 research outputs found
Towards bamboo agroforestry development in Ghana: evaluation of crop performance, soil properties and economic benefit
In the quest to promote bamboo agroforestry
in the dry semi-deciduous forest zone of
Ghana, we evaluated changes in soil properties, crop
productivity and the economic potential of a bamboobased
intercropping system. The intercropping system
was established from 3-months old sympodial
bamboo (Bambusa balcooa) seedlings planted at a
5 m95 m spacing and intercropped with maize,
cassava or cowpea. Separate monocropping fields for
maize, cassava, cowpea and bamboo were set up
adjacent to the intercropped field. In both the
intercropping and monocropping fields, plots were
with fertilizer treatments and without. The experiment
was laid out in a split plot design with four
replicates and studied over three years. Economic
analysis was conducted using the financial benefit-cost ratio method. The results showed that regardless
of fertilizer treatments, bamboo agroforestry and
monocropped fields had comparable effects on soil
properties and crop productivity within two years of
establishment. In the third year, however, bamboo
agroforestry had significantly (p\0.05) higher soil
moisture, pH and crop productivity levels. An
intercropping advantage over monocropping was
evident for all crops with respective partial land
equivalent ratios for fertilized and non-fertilized
intercropped systems as follows: cowpea (1.37 and
1.54), maize (1.38 and 1.36), and cassava (1.12 and
1.19). The economic evaluation also indicated
marginal profitability of bamboo intercropping over
monocropping systems. From the results obtained,
there are clear indications that where bamboo is a
prioritized woody perennial, integrated systems with
crops may be encouraged
Proteome and Membrane Fatty Acid Analyses on Oligotropha carboxidovorans OM5 Grown under Chemolithoautotrophic and Heterotrophic Conditions
Oligotropha carboxidovorans OM5 T. (DSM 1227, ATCC 49405) is a chemolithoautotrophic bacterium able to utilize CO and H2 to derive energy for fixation of CO2. Thus, it is capable of growth using syngas, which is a mixture of varying amounts of CO and H2 generated by organic waste gasification. O. carboxidovorans is capable also of heterotrophic growth in standard bacteriologic media. Here we characterize how the O. carboxidovorans proteome adapts to different lifestyles of chemolithoautotrophy and heterotrophy. Fatty acid methyl ester (FAME) analysis of O. carboxidovorans grown with acetate or with syngas showed that the bacterium changes membrane fatty acid composition. Quantitative shotgun proteomic analysis of O. carboxidovorans grown in the presence of acetate and syngas showed production of proteins encoded on the megaplasmid for assimilating CO and H2 as well as proteins encoded on the chromosome that might have contributed to fatty acid and acetate metabolism. We found that adaptation to chemolithoautotrophic growth involved adaptations in cell envelope, oxidative homeostasis, and metabolic pathways such as glyoxylate shunt and amino acid/cofactor biosynthetic enzymes
Carotenoids Play a Positive Role in the Degradation of Heterocycles by Sphingobium yanoikuyae
BACKGROUND: Microbial oxidative degradation is a potential way of removing pollutants such as heterocycles from the environment. During this process, reactive oxygen species or other oxidants are inevitably produced, and may cause damage to DNA, proteins, and membranes, thereby decreasing the degradation rate. Carotenoids can serve as membrane-integrated antioxidants, protecting cells from oxidative stress. FINDINGS: Several genes involved in the carotenoid biosynthetic pathway were cloned and characterized from a carbazole-degrading bacterium Sphingobium yanoikuyae XLDN2-5. In addition, a yellow-pigmented carotenoid synthesized by strain XLDN2-5 was identified as zeaxanthin that was synthesized from ÎČ-carotene through ÎČ-cryptoxanthin. The amounts of zeaxanthin and hydrogen peroxide produced were significantly and simultaneously enhanced during the biodegradation of heterocycles (carbazole < carbazole + benzothiophene < carbazole + dibenzothiophene). These higher production levels were consistent with the transcriptional increase of the gene encoding phytoene desaturase, one of the key enzymes for carotenoid biosynthesis. CONCLUSIONS/SIGNIFICANCE: Sphingobium yanoikuyae XLDN2-5 can enhance the synthesis of zeaxanthin, one of the carotenoids, which may modulate membrane fluidity and defense against intracellular oxidative stress. To our knowledge, this is the first report on the positive role of carotenoids in the biodegradation of heterocycles, while elucidating the carotenoid biosynthetic pathway in the Sphingobium genus
Microbial diversity in waters, sediments and microbial mats evaluated using fatty acid-based methods
The review summarises recent advances towards a greater comprehensive assessment of microbial diversity in aquatic environments using the fatty acid methyl esters and phospholipid fatty acids approaches. These methods are commonly used in microbial ecology because they do not require the culturing of micro-organisms, are quantitative and reproducible and provide valuable information regarding the structure of entire microbial communities. Because some fatty acids are associated with taxonomic and functional groups of micro-organisms, they allow particular groups of micro-organisms to be distinguished. The integration of fatty acid-based methods with stable isotopes, RNA and DNA analyses enhances our knowledge of the role of micro-organisms in global nutrient cycles, functional activity and phylogenetic lineages within microbial communities. Additionally, the analysis of fatty acid profiles enables the shifts in the microbial diversity in pristine and contaminated environments to be monitored. The main objective of this review is to present the use of lipid-based approaches for the characterisation of microbial communities in water columns, sediments and biomats
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