Na-Stimulated Transport of l-Methionine in Brevibacterium linens CNRZ 918

The transport of l-methionine by the gram-positive species Brevibacterium linens CNRZ 918 is described. The one transport system (K(m) = 55 muM) found is constitutive for l-methionine, stereospecific, and pH and temperature dependent. Entry of l-methionine into cells is controlled by the internal methionine pool. Competition studies indicate that l-methionine and alpha-aminobutyric acid share a common carrier for their transport. Neither methionine derivatives substituted on the amino or carboxyl groups nor d-methionine was an inhibitor, whereas powerful inhibition was shown by l-cysteine, s-methyl-l-cysteine, dl-selenomethionine and dl-homocysteine. Sodium plays important and varied roles in l-methionine transport by B. linens CNRZ 918: (i) it stimulates transport without affecting the K(m), (ii) it increases the specific activity (on a biomass basis) of the l-methionine transport system when present with methionine in the medium, suggesting a coinduction mechanism. l-Methionine transport requires an exogenous energy source, which may be succinic, lactic, acetic, or pyruvic acid but not glucose or sucrose. The fact that l-methionine transport was stimulated by potassium arsenate and to a lesser extent by potassium fluoride suggests that high-energy phosphorylated intermediates are not involved in the process. Monensin eliminates stimulation by sodium. Gramicidin and carbonyl cyanide-m-chlorophenylhydrazone act in the presence or absence of Na. N-Ethylmaleimide, p-chloromercurobenzoate, valinomycin, sodium azide, and potassium cyanide have no or only a partial inhibitory effect. These results tend to indicate that the proton motive force reinforced by the Na gradient is involved in the mechanism of energy coupling of l-methionine transport by B. linens CNRZ 918. Thus, this transport is partially similar to the well-described systems in gram-negative bacteria, except for the role of sodium, which is very effective in B. linens, a species adapted to the high sodium levels of its niche.     

Melatonin ingestion after exhaustive late-evening exercise attenuate muscle damage,oxidative stress,and inflammation during intense short term effort in the following day in teenage athletes

ABSTRACT

The present study aimed to investigate whether nocturnal melatonin (MEL) ingestion has beneficial effects against exercise-induced oxidative stress and muscle damage in young athletes. Fourteen healthy-trained teenagers performed two-test sessions separated by at least, 1 week. During each session, participants completed the Running-Based Anaerobic Sprint Test (RAST) at 20:00 h. Then, they ingested a single 10-mg tablet of MEL or Placebo (PLA) in a double-blind randomized order at 22:00 h. The following morning (i.e., 07:30 h), participants performed the same test as the previous night. Blood samples were taken before and after exercise. MEL intake increased the peak power (P_peak) (p < .01), mean power (P_mean) (p < .001) and decreased the total time (TT) (p < .001) and the fatigue index (FI) (p < .05). Furthermore, MEL ingestion attenuated the hematologic parameters before and after exercise (White Blood Cells (WBC: p < .001 and p < .001, respectively); Neutrophiles (NE: p < .001 and p < .001, respectively); Lymphocytes (LY: p < .001 and p < .001, respectively)) and the ultra-sensitive C-reactive protein (us-CRP: p < .001 and p < .001; respectively) compared to PLA. Also, MEL reduced muscle and hepatic damage enzymes before and after exercise (creatine kinase (CK: p < .001 and p < .001; respectively), lactate dehydrogenase (LDH: p < .05 and p < .01; respectively), aspartate aminotransferase (ASAT: p < .01 and p < .001; respectively)), Malondialdehyde (MDA: p < .001 and p < .001; respectively) and Homocysteine (Hcy: p < .001 and p < .001; respectively)) from placebo. Plasma lactate [La] and glucose (GL) remained unchangeable during the two conditions. In summary, acute MEL ingestion after strenuous late-evening exercise attenuated transient leucocytosis and protected against lipid peroxidation and muscle damage induced by strenuous exercise the following morning in healthy male teenage athletes.     

Influence of Culture Parameters on Biological Hydrogen Production by Clostridium saccharoperbutylacetonicum ATCC 27021

Summary Various medium components (carbon and nitrogen sources, iron, inoculum size) and environmental factors (initial pH and the agitation speed) were evaluated for their effects on the rate and the yield of hydrogen production by Clostridium saccharoperbutylacetonicum. Among the carbon sources assessed, cells grown on disaccharides (lactose, sucrose and maltose) produced on the average more than twice (2.81 mol-H2/mol sugar) as much hydrogen as monosaccharides (1.29 mol-H2/mol sugar), but there was no correlation between the carbon source and the production rate. The highest yield (2.83 mol/mol) was obtained in lactose and sucrose but the highest production rate (1.75 mmol/h) in sucrose. Using glucose as carbon source, yeast extract was the best nitrogen source. A parallel increase between the production rate and the yield was obtained by increasing glucose concentration up to 40 g/l (1.76 mol-H2/mol, 3.39 mmol/h), total nitrogen as yeast extract up to 0.1% (1.41 mol/mol, 1.91 mmol/h) and agitation up to 100 rev/min (1.66 mol-H2/mol, 1.86 mmol/h). On the other hand, higher production rates were favoured in preference to the yield at a neutral initial pH 7 (2.27 mmol/h), 1000 mg iron/l or more (1.99 mmol/h), and a larger inoculum size, 10%, (2.36 mmol/h) whereas an initial alkaline pH of 8.5 (1.72 mol/mol), a lower iron concentration of 25 mg/l (1.74 mol/mol) and smaller inoculum size, 1%, (1.85 mol/mol) promoted higher yield over production rate.     

Influence of temperature and salinity on the germination of Lotus creticus (L.) from the arid land of Tunisia

Effects of salinity, temperature and their interactions on the rate and final percentage of germination were evaluated for two populations (Msarref, Oued dkouk) of the invasive glycophyte Lotus creticus Linné, grown under arid environmental conditions of the Tunisia. Seeds that were not treated with NaCl germinated well in a wide range of temperatures. For both populations, maximum germination occurred in distilled water at 25°C and lowest germination for all salinities was at 35°C. Germination was substantially delayed and significantly reduced with an increase in NaCl to levels above 300 mm . Compared to the Oued dkouk population, final germination and germination rate of the Msarref population was completely inhibited at 300 mm NaCl. The interactive effect of temperature and NaCl concentration on final germination and germination rate was significant (P < 0.01), indicating that the germination response to salinity depended on temperature. The inhibition of Oued dkouk population seed germination at high salt concentration was mostly due to osmotic effects while ionic effects were noted at Msarref population. The germination behaviour of the Oued dkouk population would therefore imply adaptive mechanisms to saline environments, while in the Msarref population such mechanisms seem to be absent. Since seed germination is more sensitive to salinity stress than the growth of established plants, the greater tolerance to salinity of Oued dkouk population would be an adaptive feature of this population to saline environment.     

Homoeologous chromosome pairing between the A and B genomes of Musa spp. revealed by genomic in situ hybridization

Background and Aims

Most cooking banana and several desert bananas are interspecific triploid hybrids between Musa acuminata (A genome) and Musa balbisiana (B genome). In addition, M. balbisiana has agronomical characteristics such as resistance to biotic and abiotic stresses that could be useful to improve monospecific acuminata cultivars. To develop efficient breeding strategies for improving Musa cultivars, it is therefore important to understand the possibility of chromosome exchange between these two species.

Methods

A protocol was developed to prepare chromosome at meiosis metaphase I suitable for genomic in situ hybridization. A series of technical challenges were encountered, the main ones being the hardness of the cell wall and the density of the microsporocyte''s cytoplasm, which hampers accessibility of the probes to the chromosomes. Key parameters in solving these problems were addition of macerozyme in the enzyme mix, the duration of digestion and temperature during the spreading phase.

Results and Conclusions

This method was applied to analyse chromosome pairing in metaphase from triploid interspecific cultivars, and it was clearly demonstrated that interspecific recombinations between M. acuminata and M. balbisiana chromosomes do occur and may be frequent in triploid hybrids. These results provide new insight into Musa cultivar evolution and have important implications for breeding.     

Involvement of IL17A,IL17F and IL23R Polymorphisms in Colorectal Cancer Therapy

IL23/IL17 pathway plays an important role in the development of inflammatory bowel diseases (IBD). In general, the genes encoding the cytokines are genetically polymorphic and polymorphisms in genes IL23R and IL17 have been proved to be associated with its susceptibility to inflammatory diseases as well as cancer including colorectal cancer. Moreover, it has been shown that these interleukins are involved in anti-tumor or pro-tumor effects of various cancers. Previously, we showed that there is a significant association between IL17A, IL17F and IL23R polymorphisms as well as the occurrence of colorectal cancer and the clinical features of the disease. The purpose of the present work is to investigate an association between IL17A, IL17F and IL23R polymorphisms in 102 Tunisian patients with colorectal cancer treatment. The association was analyzed by statistical tools. We found that patients with mutated genotypes of IL17A G197A SNP could be a risk factor for the inefficiency of chemotherapy and radiotherapy. Unlike IL17F variant, patients with wild type genotypes require surgery and adjuvant chemotherapy. On the one hand, we found no evidence that supports a significant association between IL23R polymorphism and the combined genotypes of these three genes and the colorectal cancer treatment. On the other hand, we showed that there is an important interaction between IL17A/IL17F polymorphisms and the stage of the disease as well as its treatment. Finally, patients with IL17F wild type genotype highlighted that there is a valid longer OS without all treatments and with radiotherapy and a neoadjuvant chemotherapy. In contrast, we observed that there are no relationships between IL17A, IL23R and the survival of these patients neither with nor without the treatment. Our results suggest that polymorphisms in IL17A and IL17F genes may be a predictive source of colorectal cancer therapy type. Therefore, IL17F may serve as an independent prognostic factor for overall survival in patients with colorectal cancer.     

Influence of Oxygen and pH on Methanethiol Production from l-Methionine by Brevibacterium linens CNRZ 918

The effects of dissolved oxygen concentration and pH on the growth of Brevibacterium linens CNRZ 918 and its production of methanethiol from l-methionine were investigated. Optimal specific methanethiol production was obtained at 25% saturation of dissolved oxygen and at a pH between 8 and 9, whereas optimal cell growth occurred at 50% oxygen saturation and when the pH was maintained constantly at 7. Methanethiol production by nonproliferating bacteria required the presence of l-methionine (7 mM) in the culture medium. This was probably due to the induction of enzyme systems involved in the process. The intracellular concentration of l-methionine seemed to play a key role in this process. B. linens CNRZ 918 tolerated alkaline pHs with a maximal growth pH of approximately 9. Its orange pigmentation seemed to depend on the presence of l-methionine in the culture medium and on the concentration of dissolved oxygen.     

Hsp70-2 gene polymorphism: susceptibility implication in Tunisian patients with coronary artery disease

ABSTRACT: Coronary artery disease (CAD) is a multifactorial disease where genetic and environmental factors interact in complex ways to cause the disease. Heat shock protein genes are involved in the progress of CAD. This implies that genetic variants of Hsp70-2 genes might contribute to the development of the disease. Aim of study The aim of this study was to characterize statistical correlation of linkage between lipid profiles, polymorphism PstI site of Hsp70-2 gene and coronary artery diseases. Patients and methods This study was carried out on Tunisian patients with CAD recruited from Hospital of Fattouma Bourguiba of Monastir-Tunisia. Polymerase chain reaction and restriction enzymes were used to determine the genotypic distributions in 252 unrelated patients and 151 healthy control subjects. Further, ApoA-I and ApoB as well as the serum total of cholesterol, HDL, triglyceride, and hs-CRP levels were measured. RESULTS: We showed a decreased level of ApoA-I, whereas the levels of each of ApoB and hs-CRP were increased in patients with CAD compared with control group. In addition our studies of a polymorphic PstI site of Hsp70-2 gene lying in the coding region at position 1267 of the Hsp70-2 gene have revealed that the frequency of P1/P2 heterozygote was 0.484 in patient group compared with control group (0.476, p = 0.046). Whereas, the frequency of the P2/P2 homozygote was 0.190 in patient group and only 0.099 in controls (P = 0.006). These results indicate that the odds ratio of CAD associated with the Hsp70-2 polymorphism is confined the P2/P2 homozygotes (OR 2.498; P = 0.006). CONCLUSION: Taken together, our results indicate that the high frequency of P2/P2 genotype is associated with elevated levels of biochemical parameters (LDL cholesterol, hs-CRP) in Tunisian patient group. The Hsp70-2 polymorphism has susceptibly implication in CAD. Virtual slides The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1118340895703689.