Harmful effects of contaminants on the ecosystem and humans cannot be assessed by standard chemical analyses of environmental samples, therefore toxicity tests using live organisms or cells represent a vital part of environmental monitoring. Biological methods based on microorganisms as test-species, have already successfully been applied to environmental toxicity/genotoxicity assessment. The e...

Chitin is the second most abundant polymer in nature after cellulose and plays a major role in fungal cell walls. As a producer of variety of chitinase enzymes Trichoderma has become an important means of biological control of fungal diseases. A simple and sensitive method based on the use of basal medium with colloidal chitin as sole carbon source supplemented with Bromo cresol purple (pH indi...

in the present study, photocatalytic removal of p-nitrophenol has been carried out in the presence of zno by using a batch reactor with a uv-c lamp (15 w). the effects of applied zno concentration and uv light intensity have been studied. the increase of initial pollutant concentration decreases the removal rate, and the results indicate that the apparent reaction rate constant in the uv/zno pr...

With the unprecedented deterioration of environmental quality, rapid recognition of toxic compounds is paramount for performing in situ real-time monitoring. Although several analytical techniques based on electrochemistry or biosensors have been developed for the detection of toxic compounds, most of them are time-consuming, inaccurate, or cumbersome for practical applications. More recently, ...

An obligate anaerobic, mesophilic, motile and endospore-forming bacterium, designated 1D(T), was isolated from a subsurface soil sample. The young culture of strain 1D(T) was Gram-positive and formed oval spores that were central in position. Based on the biochemical, chemotaxonomic and physiological data, strain 1D(T) appears to be a member of the genus Clostridium. Strain 1D(T) was found to b...

Chlamydiae are prokaryotic, gram negative, intracellular parasites, causing a number of human diseases with serious sequelae. The exact mechanism of chlamydial attachment and entry into the host cell is still unclear. Chlamydia trachomatis, SA2F (L2) was tested for the activity of glycosidases. Glycosidases are involved in the synthesis and breakdown of cell-wall polysaccharides, and have a piv...

The plasma concentration of IL-18 (interferon-gamma inducing factor) was severely increased in a 3 year old boy with purine nucleoside phosphorylase (PNP) deficiency. The presence and activity of IL-18 were confirmed by immunoblotting and bioassay, respectively. These results suggest that IL-18 may be abundantly produced and secreted into plasma by PNP deficient macrophages in PNP deficiency.

Interactions of calf spleen purine nucleoside phosphorylase (PNP) with a non-typical substrate, 8-azaguanine (8-azaG), and a bisubstrate analogue inhibitor, 9-(2-phosphonylmethoxyethyl)-8-azaguanine (PME-azaG), were investigated by means of steady-state fluorescence spectroscopy. Both 8-azaG and PME-azaG form fluorescent complexes with the enzyme, and dissociation constants are comparable to th...

The K-ras mutation in pancreatic cancer can inhibit drug delivery and increase drug resistance. This is exemplified by the therapeutic effect of PH-427, a small molecule inhibitor of AKT/PDK1, which has shown a good therapeutic effect against a BxPC3 pancreatic cancer model that has K-ras, but has a poor therapeutic effect against a MiaPaCa-2 pancreatic cancer model with mutant K-ras. To increa...

We used a gene transfer-based system to generate highly toxic purine bases in tumor cells transfected with the Escherichia coli purine nucleoside phosphorylase (PNP) gene. Because these toxic purines are mem brane permeant, they mediate effective killing of neighboring cells that do not express E. coli PNP ("bystander" toxicity). In mixed cultures contain ing increasing percentages of cells wit...