The biochemical adaptations

Human glandular kallikrein 2 (hK2) is a trypsin-like serine protease expressed predominantly in the prostate epithelium. Recently, hK2 has proven to be a useful marker that can be used in combination with prostate specific antigen for screening and diagnosis of prostate cancer. The cleavage by hK2 of certain substrates in the proteolytic cascade suggest that the kallikrein may be involved in prostate cancer development; however, there has been very little other progress toward its biochemical characterization or elucidation of its true physiological role.

8p system191 01-06-2013 45 2   Download

Chlamydomonas reinhardtii, a unicellular green alga, contains a hydrogenase enzyme, which is induced by anaerobic adaptation of the cells. Using the suppression subtractive hybridization (SSH) approach, the differential expression of genes under anaerobiosis was analyzed. A PCR fragment with similarity to the genes of bacterial Fe-hydrogenases was isolated and used to screen an anaerobic cDNA expression library of C. reinhardtii.

11p research12 01-06-2013 41 6   Download

Acomputational approach is used to analyse temporal gene expression in the context of metabolic regulation. It is based on the assumption that cells developed optimal adaptation strategies to changing environmental conditions. Time-dependent enzyme profiles are calculatedwhichoptimize the function of a metabolic pathway under the constraint of limited total enzymeamount.For linearmodel pathways it is shown thatwave-like enzyme profiles are optimal for a rapid substrate turnover.

8p tumor12 22-04-2013 49 3   Download

The effects of physiologically relevant hypoxia on the catalytic activity of cytochromecoxidase (CytOX), mito-chondrial gene expression, and both nuclear and mito-chondrial encoded CytOX mRNA levels were investigated in murine monocyte macrophages, mouse C2C12 skeletal myocytes and rat adrenal pheochromocytoma PC12 cells. Our results suggest a coordinated down regulation of mito-chondrial genome-coded CytOX I and II and nuclear genome-codedCytOX IV andVbmRNAs during hypoxia.

9p tumor12 20-04-2013 35 3   Download

The classical metabolic control theory [Kacser, H. & Burns, J.A. (1973)Symp.Soc.Exp.Biol. 27, 65–104; Heinrich, R. & Rapoport, T. (1974)Eur. J. Biochem.42, 89–95.] does not take into account experimental evidence for correlations between enzyme concentrations in the cell. We investigated the implications of two causes of linear correlations: competition between enzymes, which is a mere physical adaptation of the cell to the limitation of resources and space, and regulatory correlations, which result from the existence of regulatory networks....

17p awards 05-04-2013 49 3   Download

Riftia pachyptila(Vestimentifera) is a giant tubeworm living around the volcanic deep-sea vents of the East Pacific Rise. This animal is devoid of a digestive tract and lives in an intimate symbiosis with a sulfur-oxidizing chemoauto-trophic bacterium. This bacterial endosymbiont is localized in the cells of a richly vascularized organ of the worm: the trophosome.

10p awards 05-04-2013 45 3   Download

When challenged by the dietary soybean cysteine protease inhibitor scN, the cowpea bruchid (Callosobruchus maculatus) adapts to the inhibitory effects by readjusting the transcriptome of its digestive system, including the specific activation of a cathepsin B-like cysteine protease CmCatB.

15p galaxyss3 19-03-2013 29 3   Download

Goldfish (Carassius auratus) may survive in aquatic environments with low oxygen partial pressures. We investigated the contribution of respiratory proteins to hypoxia tolerance inC. auratus. We determined the complete coding sequence of hemoglobinaandband myoglobin, as well as partial cDNAs from neuroglobin and cytoglobin.

11p galaxyss3 07-03-2013 29 3   Download

Adaptation to extreme environments affects the stability and catalytic effi-ciency of enzymes, often endowing them with great industrial potential. We compared the environmental adaptation of the secreted endonuclease I from the cold-adapted marine fish pathogenVibrio salmonicida(VsEndA) and the human pathogen Vibrio cholerae (VcEndA).

13p media19 06-03-2013 42 3   Download

Pyruvate is located at a crucial crossroad of cellular metabolism between the aerobic and anaerobic pathways. Modulation of the fate of pyruvate, in one direction or another, can be important for adaptative response to hypoxia followed by reoxygenation.

11p media19 04-03-2013 40 3   Download

In yeast, a sudden transition from glucose limitation to glucose excess leads to a new steady state at increased metabolic fluxes with a sustained decrease in the ATP concentration. Although this behaviour has been rationalized as an adaptive metabolic strategy, the mechanism behind it remains unclear.

16p vinaphone15 28-02-2013 39 4   Download

Transmissible spongiform encephalopathies (TSEs), or prion diseases, are fatal neurodegenerative disorders caused by an infectious agent termed a prion, which can convert normal cellular prion protein (PrP C ) into a patho-logically misfolded isoform (PrP Sc ). Taking advantage of protein misfolding cyclic amplification (PMCA), a series of experiments was conducted to investigate the possible influences of pyridine nucleotides on the propaga-

10p vinaphone15 27-02-2013 40 2   Download

The digestive tract of lepidopteran insects is extremely alkaline. In the pres-ent work, molecular adaptation of amylolytic enzymes to this environment was investigated in the flour moth Ephestia kuehniella, an important stored-product pest. Three digestivea-amylases [Ephestia kuehniellaa-amy-lase isoenzymes 1–3 (EkAmy1–3)] with an alkaline pH optimum were puri-fied from larvae and biochemically characterized.

16p viettel02 22-02-2013 44 2   Download

In living organisms, genes encoding proteins that contain flavins as a pros-thetic group constitute approximately 2–3% of the total. The fluorescence of flavin cofactors in these proteins is a property that is widely employed for biochemical characterisation. Here, we present a modified Thermofluor  approach called ThermoFAD (Thermofluor  -adapted flavin ad hoc detec-tion system), which simplifies identification of optimal purification and storage conditions as well as high-affinity ligands.

8p viettel02 22-02-2013 38 5   Download

The dominant perciform suborder Notothenioidei is an excellent study group for assessing the evolution and functional importance of biochemical adaptations to temperature. The availability of notothenioid taxa in a wide range of latitudes (Antarctic and non-Antarctic) provides a tool to enable identification of physiological and biochemical characteristics gained and lost during evolutionary history.

12p viettel02 22-02-2013 37 3   Download

In ruminants, some leaf-eating animals, and some insects, defensive lyso-zymes have been adapted to become digestive enzymes, in order to digest bacteria in the stomach. Digestive lysozyme has been reported to be resis-tant to protease and to have optimal activity at acidic pH. The structural basis of the adaptation providing persistence of lytic activity under severe gastric conditions remains unclear.

9p viettel02 22-02-2013 38 3   Download

The term ‘antimicrobial peptides’ refers to a large number of peptides first characterized on the basis of their antibiotic and antifungal activities. In addition to their role as endogenous antibiotics, antimicrobial peptides, also called host defense peptides, participate in multiple aspects of immunity (inflammation, wound repair, and regulation of the adaptive immune sys-tem) as well as in maintaining homeostasis.

12p viettel02 20-02-2013 46 3   Download

The heat shock response was originally characterized as the induction of a set of major heat shock proteins encoded by heat shock genes. Because heat shock proteins act as molecular chaperones that facilitate protein fold-ing and suppress protein aggregation, this response plays a major role in maintaining protein homeostasis.

14p viettel02 19-02-2013 45 4   Download

Peroxisomes are cell organelles that are present in almost all eukaryotic cells and involved in a large range of metabolic pathways. The organelles are highly dynamic in nature: their number and enzyme content is highly variable and continuously adapts to prevailing environmental conditions. This review summarizes recent relevant developments in research on pro-cesses that are involved in the regulation of peroxisome abundance and maintenance.

10p viettel02 19-02-2013 32 3   Download

Define ecological biochemistry. • Explain biochemical adaptation and the roles of secondary compounds. • Describe detoxification and the primary metabolic pathways in plants and animals. • Explain the key processes and factors involved in biotransformation & biodegradation. • Explain the concepts of sequestration, bioaccumulation, and biomagnification. • Contrast different forms of ecological biochemical interaction.

8p nguyenvanquan037 07-01-2011 70 4   Download