Formation of wheat (<Emphasis Type="Italic">Triticum aestivum</Emphasis> L.) embryogenic callus involves peroxide-generating germin-like oxalate oxidase

In wheat ( Triticum aestivum L.), embryogenic callus formation comprises suppression of precocious germination by the zygotic embryo and the initiation of dedifferentiated cellular proliferation within it. Embryogenic calli are induced by treating immature embryos with 2,4-dichlorophenoxyacetic acid (2,4-D). Upon withdrawal from 2,4-D, somatic embryos develop from the periphery of the callus. Prior to visible callus formation, there is a striking induction of "germin-like" oxalate oxidase ("gl-OXO": EC 1.2.3.4) gene expression. Accumulation of gl-OXO mRNA is rapidly stimulated upon auxin treatment, with a consequent development of apoplastic enzyme activity producing H(2)O(2) within the cell wall. Within the dedifferentiated calli, gl-OXO enzyme activity becomes widespread over the surface of embryogenic calli. Differentiation of somatic embryos is initiated in regions of densely cytoplasmic, meristematic cells that are marked by highly localised expression of gl-OXO activity within these embryogenic cell masses. We suggest that this localised generation of H(2)O(2) by gl-OXO promotes peroxidative cross-linking of cell wall components, thereby preventing cellular expansion and maintaining these cell masses in an embryogenically competent condition.     

Determination of degradation of radioactivity and its kinetics in aerobic composting

In this study, the kinetics of disappearance of radioactivity in aerobic composting was investigated. For this purpose, compost materials were prepared by mixing sugar beet wastes, wine factory wastes (grape wastes), straw and biological treatment sludge in different amounts. While alpha-radioactivity was not initially detected in all composting materials, the composting materials had some beta-radioactivity. In the mixtures of sugar beet wastes--straw-biological treatment sludge (1), sugar beet wastes-wine factory wastes (grape wastes)-biological treatment sludge (II) and wine factory wastes (grape wastes)-biological treatment sludge (III), the beta-radioactivity reduced by 82%, 58%, 85% respectively of initial values after 52 d. The beta-radioactivity degradation in the composting process could be represented by first-order kinetics and reaction rate constants of mixtures of I, II and III were k = 0.0693 d(-1) (R2 - 0.84), k = 0.0453 d(-1) (R2 = 0.98), k = 0.0234 d(-1) (R2 = 0.97), respectively.     

Dietary Exposure to PCDD/Fs Through Animal Products in a Highly Polluted Area in Turkey

We present an estimation of dietary exposure to PCDD/Fs by animal products in Kocaeli, a highly polluted area in Turkey, based on current food data consumption. The calculation of the PCDD/F intakes by an exposure methodology concerning consumption habits of different receptor groups in Kocaeli was included. The data relate to the PCDD/F levels in food groups of animal origin (milk, egg, meat, chicken, and fish), food consumption rates, and the fractions of locally grown foods in total consumption were statistically assessed. Monte Carlo simulation was used to estimate the ranges of PCDD/F doses through the consumption of animal products. The PCDD/F intakes through the consumption of animal products were calculated to average between 0.4–1.8 pg WHO-TEQ.kg^?1 bodyweight (bw).day^?1. The results are within the range of 1–4 pg WHO-TEQ.kg^?1 bw.day^?1, proposed as the tolerable daily intake by the World Health Organization. On the other hand, contributions of the consumption of different foods to the total PCDD/F intake and the results of sensitivity analysis showed that the PCDD/F intake in semi-urban and rural settings was determined primarily by the consumption of milk products, while consumption of meat and fish had a greater importance in urban settings.     

A comparative tool for the validity of rate kinetics in ion channels by Onsager reciprocity theorem

The precise form of the rate constant functions of ion channels is very crucial for reproducing the electrophysiological behavior. Therefore, how well they account for experimental data plays an important role in the behavior of the model. In this study, we derive kinetic coefficients of activation and inactivation gates in ion channels by Onsager reciprocity theorem for an ensemble of gating particles, and propose that the obtained kinetic coefficients can be used as a comparative tool for the empirical validity of fitted rate constant functions to experimental data. We also illustrate its applicability based on the activation and inactivation kinetics of T-type calcium channel in thalamic relay neurons. We show that the shape of the steady-state curve by itself seems to be a poor indicator of the functional form of the rate functions, but the time constant curves reflect considerable variation depending on the particular form of the rate functions, and that the kinetic coefficients related to the time constants provide a powerful tool to determine the empirical validity of the fitted rate constants.     

The effect of L-NAME administrations after oral mucosal incision on wound NO level in rabbit

The aim of the current study was to comparatively investigate the effect of inhibition of nitric oxide (NO) production by N-nitro-L-arginine methyl ester (L-NAME), an isoform non-specific inhibitor of nitric oxide synthase (NOS), after oral mucosal incision on wound tissue NO levels. A standard incision was applied to the oral mucosa of rabbits. After oral mucosal incision, rabbits were divided into five groups as follows: (1) Untreated incisional group (control); (2) Titanium (Ti) implanted group; (3) Ti + Polyethylene glycol (PEG) 4000 implanted group; (4) Ti + PEG 4000 + L-NAME (2 × 10⁻⁴ M) implanted group and (5) i.p. L-NAME administrated group (10 mg/kg). At 5 days after oral incision operations, wound tissue strips and plasma were obtained from rabbits. Oral wound tissue and plasma nitric oxide, plasma thiobarbituric acid reactive substances (TBARS) and total sulfhydryl group (RSH) levels were investigated. Plasma TBARS and NOx levels decreased after i.p. L-NAME administration. Total RSH group levels were not changed in all groups (p>0.05). This means that L-NAME inhibits the deteriorating effects of free radicals without affecting healing. L-NAME in PEG and titanium also has no effect on tissue and plasma NOx levels. These findings indicate that NO generation will not be affected both Ti and local nitric oxide synthase (NOS) inhibitor. (Mol Cell Biochem 278: 65–69, 2005)     

Adsorption of metal complex dyes from aqueous solutions by pine sawdust

An attempt to alleviate the problem caused by the presence of metal complex dyes, mostly used in textile industries, in the textile effluents was undertaken. The effects of adsorbent particle size, pH, adsorbent dose, contact time and initial dye concentrations on the adsorption of metal complex dyes by pine sawdust was investigated. Acidic pH was favorable for the adsorption of metal complex dyes. A contact time of 120 min was required to reach the equilibrium. The experimental isotherm data were analyzed using the Langmuir, Freundlich and Temkin equations. The equilibrium data fit well the Langmuir isotherm. The monolayer adsorption capacities are 280.3 and 398.8 mg dye per g of pine sawdust for Metal Complex Blue and Metal Complex Yellow, respectively. The results indicate that pine sawdust could be employed as low-cost alternative to commercial activated carbon in aqueous solution for the removal of metal complex dyes.     

The agnoprotein of polyomaviruses: a multifunctional auxiliary protein

The late region of the three primate polyomaviruses (JCV, BKV, and SV40) encodes a small, highly basic protein known as agnoprotein. While much attention during the last two decades has focused on the transforming proteins encoded by the early region (small and large T-antigens), it has become increasingly evident that agnoprotein has a critical role in the regulation of viral gene expression and replication, and in the modulation of certain important host cell functions including cell cycle progression and DNA repair. The importance of agnoprotein is underscored by its expression during lytic infection of glial cells by JCV that occurs in progressive multifocal leukoencephalopathy (PML), and also in some JCV-associated human neural tumors particularly medulloblastoma. In this review, we will discuss the structure and function of agnoprotein in the viral life cycle during the course of lytic infection and the consequences of agnoprotein expression for the host cell.     

Attitude toward genetic testing for cancer risk in Istanbul

To identify attitudes toward genetic testing, and the effects of this information on decisions regarding issues such as pregnancy, abortion, and prophylactic surgery, several subsets of the Turkish population were surveyed in hospital settings. Individuals (n = 179) chosen arbitrarily from four different subsets of a Turkish population were asked to participate in a confidential 23-question survey. Survey participants were familiar with the concept of cancer being a familial disease (85.5%), and 84.7% of them expressed interest in genetic testing to determine cancer risk, 83.9% would have their fetuses tested for such cancer risk, 65.1% would terminate their pregnancies, 92.2% would have their children tested if they were determined to have an increased cancer risk, 71.9% would agree to undergo prophylactic oophorectomy or orchiectomy and 67.6% would have mastectomy/prostatectomy should there be an increased cancer risk to these organs. It appears that at least the sampled segment of a Turkish population is willing to undergo genetic testing to determine if they are at increased risk for cancer. The feasibility and acceptance of genetic testing and the influence of education and genetic counseling in the Turkish people should further be evaluated with a larger stratified sample of the population.     

A Proteomic Approach Provides New Insights into the Control of Soil-Borne Plant Pathogens by Bacillus Species

Beneficial microorganisms (also known as biopesticides) are considered to be one of the most promising methods for more rational and safe crop management practices. We used Bacillus strains EU07, QST713 and FZB24, and investigated their inhibitory effect on Fusarium. Bacterial cell cultures, cell-free supernatants and volatiles displayed varying degrees of suppressive effect. Proteomic analysis of secreted proteins from EU07 and FZB24 revealed the presence of lytic enzymes, cellulases, proteases, 1,4-β-glucanase and hydrolases, all of which contribute to degradation of the pathogen cell wall. Further proteomic investigations showed that proteins involved in metabolism, protein folding, protein degradation, translation, recognition and signal transduction cascade play an important role in the control of Fusarium oxysporum. Our findings provide new knowledge on the mechanism of action of Bacillus species and insight into biocontrol mechanisms.