Escherichia coliphosphotransacetylase (Pta) catalyzes the reversible inter-conversion of acetyl-CoA and acetyl phosphate. Both compounds are
critical in E. colimetabolism, and acetyl phosphate is also involved in
the regulation of certain signal transduction pathways. Along with acetate
kinase, Pta plays an important role in acetate production when E.
Phthiocerol and phthiodiolone dimycocerosates (DIMs) and phenolic gly-colipids (PGLs) are complex lipids located at the cell surface ofMycobacte-rium tuberculosis that play a key role in the pathogenicity of tuberculosis.
Most of the genes involved in the biosynthesis of these compounds are
clustered on a region of the M. tuberculosischromosome, the so-called
DIM + PGL locus.
Chemical substances (also called pure substances) may well be defined as "any material with a definite chemical composition" in an introductory general chemistry textbook. According to this definition a chemical substance can either be a pure chemical element or a pure chemical compound. But, there are exceptions to this definition; a pure substance can also be defined as a form of matter that has both definite composition and distinct properties. The chemical substance index published by CAS also includes several alloys of uncertain composition.
After the ground breaking discovery of electrical charge carrier transport in
polymers in the late 1980s by Alan J. Heeger, Alan G. MacDiarmid and Hideki
Shirakawa [1–3], who were awarded the Nobel Prize in chemistry in 2000, the
question arose as to whether organic materials would also find applications as
organic semiconductors. This field really started to attract major attention after
the demonstration of the first organic light emitting device (OLED) in 1987 by
Tang and Van Slyke .
In gravity injection, small volumes of reagents are gravity-fed into injection
well(s) over a longer application period. The distribution and dissipation of the
reagents in the saturated zone is largely controlled by the site hydrogeologic
conditions. The gravity injection approach may reduce some of risks associated
with chemical oxidation technologies. Additionally, given its prolonged
application period, the oxidants may be able to penetrate into more of the lower
permeability soils to address contaminants in these areas.
Plants defend themselves from other organisms by elaborating bioactive chemical
defences. This is the essential basis of the use of herbal medicines that still represents a
major therapeutic resort for much of humanity However, at the outset, it must be stated that
any plant that is not part of our evolved dietary cultures is potentially dangerous.
Commercial herbal medicinal preparations approved by expert regulatory authorities have a
significant place in mainstream conventional medicine and in complementary medicine.
Chemists frequently refer to chemical compounds using chemical formulae or molecular structure of the compound. There has been a phenomenal growth in the number of chemical compounds being synthesized (or isolated), and then reported in the scientific literature by professional chemists around the world. An enormous number of chemical compounds are possible through the chemical combination of the known chemical elements. As of May 2011, about sixty million chemical compounds are known.
The protein arginine methyltransferase (PRMT) family of enzymes cata-lyzes the transfer of methyl groups from S-adenosylmethionine to the gua-nidino nitrogen atom of peptidylarginine to form monomethylarginine or
dimethylarginine. We created several less polar analogs of the specific
PRMT inhibitor arginine methylation inhibitor-1, and one such compound
was found to have improved PRMT inhibitory activity over the parent
There is a growing body of evidence which demonstrates
that following a diet that complies with the Dietary
Guidelines may reduce the risk of chronic disease.
Recently, it was reported that dietary patterns consistent
with recommended dietary guidance were associated
with a lower risk of mortality among individuals age 45
years and older in the United States.
Consequently the chemical contamination builds to
higher levels in these organisms. Indigenous peoples in the Arctic, whose traditional diets are
heavy in fatty foods and who often have no alternatives for nourishment, thus have some of
the highest recorded levels of POPs. Yet they are hundreds or thousands of kilometres from
where these pesticides and industrial chemicals were released, and they certainly received
little benefit from the chemicals' original use.
Freshwater sponges are common animals of most aquatic ecosystems. They utilize flagellated
choanocytes to pump water through a series of canals. Incoming water enters through ostia, passes
through choanocyte chambers, and exits through the osculum. Bacteria are filtered from incoming
water, and large volumes of water can pass through a sponge in a 24-hour period. Because of their
simple morphological construction, many cells come into direct contact with the surrounding water
as the sponge pumps.
High-molecular-mass PC complexes (PC-HMWCs) constituted by phyto-chelatins (PCs), cadmium and sulfide are synthesized by several organisms
after exposure to cadmium. In this study, PC-HMWCs were isolated from
photoheterotrophicEuglena gracilisand purified to homogeneity, resulting
in compounds of molecular mass 50–380 kDa depending on the CdCl2and
sulfate concentrations in the culture medium.
Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành y học dành cho các bạn tham khảo đề tài: Molecular understanding of sterically controlled compound release through an engineered channel protein (FhuA)
Copper fungicides are environmentally unfriendly. They are very toxic to fish and aquatic
invertebrates, such as crab, shrimp and oysters. There are cases where most animal life in soil,
including large earthworms, have been eliminated by the extensive use of copper-containing
fungicides in orchards. It is strongly bioaccumulated and is very persistent. Once a soil is
contaminated with copper, there is no practical way to remove it.
The organic insecticide rotenone has been found to be toxic to pigs, rats and dogs and is is very
toxic to fish. It causes skin and eye irritations.
Most drugs against malaria that are available or under development target
a single process of the parasite infective cycle, favouring the appearance of
resistant mutants which are easily spread in areas under chemotherapeutic
The metallo-b-lactamase (MBL) GOB-1 was expressed via a T7 expression
system in Escherichia coliBL21(DE3). The MBL was purified to homoge-neity and shown to exhibit a broad substrate profile, hydrolyzing all the
tested b-lactam compounds efficiently.
Lactococcus lactiscan decrease the redox potential at pH 7 (Eh7) from 200
to )200 mV in oxygen free Man–Rogosa–Sharpe media. Neither the con-sumption of oxidizing compounds or the release of reducing compounds
during lactic acid fermentation were involved in the decrease inEh7by the
Haem (protohaem IX) analogues are toxic compounds and have been con-sidered for use as antibacterial agents, but the primary mechanism behind
their toxicity has not been demonstrated. Using the haem protein catalase
in the Gram-positive bacterium Enterococcus faecalisas an experimental
system, we show that a variety of haem analogues can be taken up by bac-terial cells and incorporated into haem-dependent enzymes.
Sodium 2-propenyl thiosulfate, a water-soluble organo-sulfane sulfur com-pound isolated from garlic, induces apoptosis in a number of cancer cells.
The molecular mechanism of action of sodium 2-propenyl thiosulfate has
not been completely clarified. In this work we investigated, byin vivo and
in vitro experiments, the effects of this compound on the expression and
activity of rhodanese.
Phthiocerol dimycocerosates and related compounds are important mole-cules in the biology of Mycobacterium tuberculosis, playing a key role in
the permeability barrier and in pathogenicity. Both phthiocerol dimyco-cerosates, the major compounds, and phthiodiolone dimycocerosates, the
minor constituents, are found in the cell envelope ofM. tuberculosis, but
their specific roles in the biology of the tubercle bacillus have not been