Tropical forests have high rates of soil carbon cycling, but little information is available on how roots, arbuscular mycorrhizal fungi (AMF), and free-living microorganisms interact and influence organic matter mineralization in these ecosystems. We used mesh ingrowth cores and isotopic tracers in phospholipid fatty acid biomarkers to investigate the effects of roots and AMF mycelia on (1) mic...

Barren high-altitude soils are among the most extreme terrestrial environments on Earth. The present study was undertaken to quantify broad-scale patterns of total microbial biomass in unvegetated soils in the subnival zone of the Colorado Front Range and the high Andes of Perú. In order to better understand the limiting factors and substrates used by this community, we measured microbial bioma...

The relationship between plant species coexistence and soil microbial communities under heavy metal pollution has attracted much attention in ecology. However, whether plant species coexistence could offset the impacts of heavy metal combined pollution on soil microbial community structure and soil enzymes activities is not well studied. The modified ecological dose model and PCR-RAPD method we...

A fiber-optic microbial biosensor suitable for direct measurement of organophosphate nerve agents was developed. The unique features of this novel microbial biosensor were the recombinant Escherichia coli cells expressing the enzyme organophosphorus hydrolase on the cell surface and the optical detection of the products of enzyme-catalyzed organophosphate hydrolysis. The use of cells with the m...

perform regioand stereo-selective reactions on organic compounds. The different possible microbial reactions include oxidation, reduction, and degradative reactions. Many of these reactions allow the production of new compounds that would be extremely difficult to synthesize chemically. For instance hydroxylation at inactivated methylene is a very common microbial reaction. The results obtained...

The effects of repeated atrazine application (40 mg a.i.kg(-1)) on its degradation, microbial communities and enzyme activities were studied in a peat based biomixture composed by straw, soil and peat in the volumetric proportions of 2:1:1 that can be used in on-farm biopurification system. Atrazine removal efficiency was high (96%, 78% and 96%) after each atrazine application and did not show ...

Successional changes of terrestrial vegetation can profoundly influence stream ecosystem structure and function. We hypothesized that microbial enzyme production and community structure in stream beds depend on terrestrial litter inputs that reflect different stages of riparian succession. Outdoor experimental channels were supplied with leaf-litter of varying quantities and qualities to mimic ...

The long-term application of excessive chemical fertilizers has resulted in the degeneration of soil quality parameters such as soil microbial biomass, communities, and nutrient content, which in turn affects crop health, productivity, and soil sustainable productivity. The objective of this study was to develop a rapid and efficient solution for rehabilitating degraded cropland soils by precis...

Microbes emit volatile compounds that affect plant growth and development. However, little or nothing is known about how microbial emissions may affect primary carbohydrate metabolism in plants. In this work we explored the effect on leaf starch metabolism of volatiles released from different microbial species ranging from Gram-negative and Gram-positive bacteria to fungi. Surprisingly, we foun...

Bacillus cereus SM3 was isolated on a mineral salts medium with Tween 80 as the primary carbon source. It was able to hydrolyze second- and third-generation pyrethroids, thereby generating noninsecticidal products. The enzyme responsible for this hydrolytic reaction was named permethrinase for this study. This is the first instance in which pyrethroid detoxification has been achieved with a cel...