Isolation and Characterization of Thermophilic Bacterial Strains with Inulinase Activity

Nine bacterial strains growing on inulin as the sole carbon and energy source were isolated from soil samples by enrichment culture on a mineral medium. Four of the strains were thermophilic and belong to the genus Bacillus. The thermophilic strains synthesized a β-fructosidase that was active on both inulin and sucrose. The presence of inulin in the culture medium is necessary for enzyme synthesis. Most of the activity on inulin was recovered in the culture medium, and the enzyme was synthesized during cell growth.     

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.     

Performances de la scintigraphie parathyroïdienne au 99mTc-Sestamibi dans l’hyperparathyroïdie secondaire (à propos de 20 cas)

Aim of the studyTo evaluate the performance of the ^99mTc-Sestamibi parathyroid scintigraphy and to compare it with the performance of cervical ultrasonography in patients with secondary hyperparathyroidism who are candidates for parathyroidectomy.Patients and methodsWe performed a retrospective study including 20 patients with severe secondary hyperparathyroidism who underwent parathyroid scintigraphy in the nuclear medicine department of Sfax, during the period between January 2009 and June 2012. Our two days protocol included dual-phase, MIBI/Tc subtraction and single photon emission photons (SPECT) techniques. We analyzed the results obtained from each technique alone, then from combinations thereof. For all patients, we have collected the surgical and histopathological data as well cervical ultrasound if available.ResultsThe subtraction technique was the best performing with a sensitivity of 47% and an accuracy of 55%. The combination of subtraction scintigraphy and SPECT has improved the sensitivity to 53%and accuracy to 57%. The combined lecture of ultrasound and scintigraphy has given the best performance with a sensitivity of 58%, a specificity of 83% and an accuracy of 66%.ConclusionParathyroid scintigraphy combining subtraction and SPECT showed better reliability. The coupling with ultrasound is essential to improve results. The poor performance of scintigraphy in secondary hyperparathyroidism implies that it should be required only to search for ectopic or supernumerary glands.     

Molecular optimization of rabies virus glycoprotein expression in Pichia pastoris

In this work, different approaches were investigated to enhance the expression rabies virus glycoprotein (RABV‐G) in the yeast Pichia pastoris; this membrane protein is responsible for the synthesis of rabies neutralizing antibodies. First, the impact of synonymous codon usage bias was examined and an optimized RABV‐G gene was synthesized. Nevertheless, data showed that the secretion of the optimized RABV‐G gene was not tremendously increased as compared with the non‐optimized one. In addition, similar levels of RABV‐G were obtained when α‐factor mating factor from Saccharomyces cerevisiae or the acid phosphatase PHO1 was used as a secretion signal. Therefore, sequence optimization and secretion signal were not the major bottlenecks for high‐level expression of RABV‐G in P. pastoris. Unfolded protein response (UPR) was induced in clones containing high copy number of RABV‐G expression cassette indicating that folding was the limiting step for RABV‐G secretion. To circumvent this limitation, co‐overexpression of five factors involved in oxidative protein folding was investigated. Among these factors only PDI1, ERO1 and GPX1 proved their benefit to enhance the expression. The highest expression level of RABV‐G reached 1230 ng ml^?1. Competitive neutralizing assay confirmed that the recombinant protein was produced in the correct conformational form in this host.     

Square‐Centimeter‐Sized High‐Efficiency Polymer Solar Cells: How the Processing Atmosphere and Film Quality Influence Performance at Large Scale

Organic solar cells based on two benzodithiophene‐based polymers (PTB7 and PTB7‐Th) processed at square centimeter‐size under inert atmosphere and ambient air, respectively, are investigated. It is demonstrated that the performance of solar cells processed under inert atmosphere is not limited by the upscaling of photoactive layer and the interfacial layers. Thorough morphological and electrical characterizations of optimized layers and corresponding devices reveal that performance losses due to area enlargement are only caused by the sheet resistance of the transparent electrode reducing the efficiency from 9.3% of 7.8% for PTB7‐Th in the condition that both photoactive layer and the interfacial layers are of high layer quality. Air processing of photoactive layer and the interfacial layers into centimeter‐sized solar cells lead to additional, but only slight, losses (<10%) in all photovoltaic parameters, which can be addressed to changes in the electronic properties of both active layer and ZnO layers rather than changes in layer morphology. The demonstrated compatibility of polymer solar cells using solution‐processed photoactive layer and interfacial layers with large area indicates that the introduction of a standard active area of 1 cm² for measuring efficiency of organic record solar cells is feasible. However electric standards for indium tin oxides (ITO) or alternative transparent electrodes need to be developed so that performance of new photovoltaic materials can be compared at square centimeter‐size.     

Nighttime evaporative demand induces plasticity in leaf and root hydraulic traits

Increasing evidence suggests that nocturnal transpiration rate (TR_N) is a non‐negligible contributor to global water cycles. Short‐term variation in nocturnal vapor pressure deficit (VPD_N) has been suggested to be a key environmental variable influencing TR_N. However, the long‐term effects of VPD_N on plant growth and development remain unknown, despite recent evidence documenting long‐term effects of daytime VPD on plant anatomy, growth and productivity. Here we hypothesized that plant anatomical and functional traits influencing leaf and root hydraulics could be influenced by long‐term exposure to VPD_N. A total of 23 leaf and root traits were examined on four wheat (Triticum aestivum) genotypes, which were subjected to two long‐term (30 day long) growth experiments where daytime VPD and daytime/nighttime temperature regimes were kept identical, with variation only stemming from VPD_N, imposed at two levels (0.4 and 1.4 kPa). The VPD_N treatment did not influence phenology, leaf areas, dry weights, number of tillers or their dry weights, consistently with a drought and temperature‐independent treatment. In contrast, vein densities, adaxial stomata densities, TR_N and cuticular TR, were strongly increased following exposure to high VPD_N. Simultaneously, whole‐root system xylem sap exudation and seminal root endodermis thickness were decreased, hypothetically indicating a change in root hydraulic properties. Overall these results suggest that plants ‘sense’ and adapt to variations in VPD_N conditions over developmental scales by optimizing both leaf and root hydraulics.     

Associations of rs1883832 and rs4810485 polymorphisms of CD40 gene with myocardial infarction in the Tunisian population

Context: Cluster of differentiation 40 (CD40), and its ligand CD40L, are major co-stimulatory molecules whose interactions are important in both cellular and humoral immunity, and has been suggested to play a role in the pathogenesis of acute coronary syndrome.

Objective: The aim of this study was to examine the association of CD40 polymorphisms (-1?C>T (rs1883832) and 945G>T (rs4810485)) and myocardial infarction (MI), and to test the association of CD40 gene haplotypes with MI in Tunisians.

Materials and methods: Three hundred and fifty MI patients and 301 apparently healthy controls were included in the study. The polymorphisms of CD40 were analyzed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP).

Results: There were significant differences in the genotype and allele frequencies of CD40 gene -1?C>T (rs1883832) polymorphism between cases and controls. Stratifying according to gender, the association between the TT genotype and MI was statistically significant in males, only. Haplotype analysis revealed that the C-T and T-G haplotypes were associated with an increased risk of MI (p?=?0.012 and p?<?0.001, respectively).

Conclusions: Our work showed a significant association between the -1?C>T (rs1883832) polymorphism of the CD40 gene and MI in the Tunisians.     

Iron-superoxide dismutase and monodehydroascorbate reductase transcripts accumulate in response to internode rubbing in tomato

A cDNA encoding an iron-superoxide dismutase (Fe-SOD) was isolated by RACE-PCR from a Lycopersicon esculentum cDNA library. The Fe-SOD cDNA consists of a 746-bp open reading frame and is predicted to encode a protein of 249 amino acids with a calculated molecular mass of 27.9 kDa. The deduced amino acid sequence was very similar to other plant Fe-SODs and a potential chloroplastic targeting was found. To study the induction of oxidative burst in response to mechanical stimulation, the accumulation of Fe-SOD and monodehydroascorbate reductase (MDHAR) mRNAs was analysed in response to young growing internode rubbing in tomato plants. Northern analyses show that Fe-SOD mRNA and MDHAR mRNA accumulated in tomato internodes 10 min after the mechanical stimulation. These results suggest that reactive oxygen species are early involved in the response of a plant to a mechanical stimulation, such as rubbing. The nucleotide sequence data reported in this paper will appear in the NCBI Nucleotide Sequence Databases under the accession number AY262025.     

Thigmomorphogenesis in Solanum lycopersicum: Morphological and biochemical responses in stem after mechanical stimulation

The activation of the phenylpropanoid pathway in plants by environmental stimuli is one of the most universal biochemical stress responses known. In tomato plant, rubbing applied to a young internode inhibit elongation of the rubbed internode and his neighboring one. These morphological changes were correlated with an increase in lignification enzyme activities, phenylalanine ammonia-lyase (PAL), cinnamyl alcohol dehydrogenase (CAD) and peroxidases (POD), 24 hours after rubbing of the forth internode. Furthermore, a decrease in indole-3-acetic acid (IAA) content was detected in the rubbed internode and the upper one. Taken together, our results suggest that decrease in rubbed internode length is a consequence of IAA oxidation, increases in enzyme activities (PAL, CAD and POD), and cell wall rigidification associated with induction of lignification process.Key words: Mechanical stimulation, PAL, CAD, POD, IAAIn their environment, plants are constantly submitted to several stimuli such as wind, rain and wounding. The growth response of plants to such stimuli was termed thigmomorphogenesis and was observed in a wide range of plants.^1–3 The most common thigmomorphogenetic response is a retardation of tissue elongation accompanied by an increase in thickness.⁴ The plant response to mechanical perturbation is mainly restricted to the young developing internode, since no influence can be detected when the internode has reached its final length.^5,6 These plant growth modifications, which characterize thigmomorphogenesis, are related to biochemical events associated with lignification process⁷ and ethylene production.^8,9In tomato plant the length of internodes 4 (N4) and 5 (N5) was measured 14 days after rubbing of the fourth internode. Results reported in Figure 1 show that rubbing led to a significant reduction of elongation of the stressed internode (N4) (decrease of N4 length from 4.3 cm in the control plant to 2.9 in the rubbed one). This effect was not limited to the rubbed area but affected also the elongation of the neighboring internodes (N5) that were shorter in rubbed plants than in control ones.Open in a separate windowFigure 1Internode lengths of control and rubbed plants measured 14 day after mechanical stress applied to the fourth internode. Standard errors are indicated by vertical bars.Results reported in Figure 2 show an increase in PAL activity in both internodes N4 and N5, 24 hours after mechanical stress application as compared with corresponding controls. CAD activity was also investigated in N4 and N5, 24 h after rubbing of the fourth internode. Results presented in Figure 3 show that mechanical stress application induces a strong increase of CAD activity in the rubbed internode N4 (5.3 nkatal μg-1 protein) with an approximately two-fold increase when compared to control tomato internodes (2.3 nkatal μg-1 protein). Further, CAD activity in N5 was also increased in the rubbed internode (5.538 nkatal μg-1 protein) as compared with the control one (3.256 nkatal μg-1 protein).Open in a separate windowFigure 2PAL activity of internode 4, and 5 in control and rubbed plants 24 h after rubbing of the fourth internode. Standard errors are indicated by vertical bars.Open in a separate windowFigure 3CAD activity of internode 4, and 5 in control and rubbed plants 24 h after rubbing of the fourth internode. Standard errors are indicated by vertical bars.Syringaldazine (S-POD) and gaïacol (G-POD) peroxidase activities were measured in tomato N4 and N5. Results reported in Figure 4 show an increase in soluble peroxidase activity with both substrates in the rubbed internode N4 as compared with control plant. Enhancement in peroxidase activities in N4 was more pronounced with gaïacol (80.7 U) as an electron donor than syringaldazine (33.8 U). Similar results were observed in internode 5 as compared with control one (Fig. 4).Open in a separate windowFigure 4(A) Syringaldazine-POD (Syr-POD) activity of internode 4 and 5 in control and rubbed plants 24 h after rubbing of the fourth internode. Standard errors are indicated by vertical bars. (B) Gaiacol-POD (G-POD) activity of internode 4 and 5 in control and rubbed plants 24 h after rubbing of the fourth internode. Standard errors are indicated by vertical bars.IAA was quantified in control and rubbed plant internodes 24 h after rubbing of the fourth internode. Results reported in figure 5 show that in control sample and as expected, the content of IAA was found to be higher in the younger internode (N5) as compared to the older one (N4). Rubbing led to a significant decrease in IAA levels in N4 (5.06 nmol g⁻¹ MF⁻¹) as compared with corresponding controls (7.27 nmol g⁻¹ MF⁻¹). Similar results were observed in internode 5, where IAA content was reduced from 16.52 nmol g⁻¹ MF⁻¹ in control internode to 12.35 nmol g⁻¹ MF⁻¹ in the rubbed internode (Fig. 5).Open in a separate windowFigure 5IAA Level of internode 4 and 5 in control and rubbed plants 24 h after rubbing of the fourth internode. Standard errors are indicated by vertical bars.The results reported here establish an evident correlation between growth limitation of the rubbed internode and their degree of lignification, the increase in lignification enzymes activities and auxin degradation after mechanical stress application.Auxin seems to be involved in thigmomorphogenesis.¹⁰ It was proposed that MIS (Mechanically-induced stress) has opposite effects on auxin levels in the two species studied to date, Phaseolus vulgaris¹⁰ and Bryonia dioica.^11,12 Auxin level as measured by bioassay, increased in Phaseolus vulgaris following rubbing of the stem.¹⁰ It was proposed that a build up of auxin may result from the reduced polar transport of IAA at the rubbed internode, causing a build up of IAA in the stem tissue. Exogenous IAA did not reverse the MIS inhibition of growth in Phaseolus vulgaris and high levels of IAA retarded growth in non-stressed plants.¹⁰ Thus, retardation of extension growth in Phaseolus vulgaris may have been caused by high levels of endogenous auxin and the increase in stem diameter by increased ethylene production.⁴ However, ethylene increases radial growth only if auxin is present.¹³Boyer¹¹ reported a decrease in auxinlike activity in Bryonia dioica following MIS and this was confirmed in the same species by Hofinger et al.¹² who reported a decrease in IAA using gas chromatography-mass spectrometry. Auxin catabolism was accompanied with changes in both soluble and ionically bound cell wall basic peroxidases¹⁴ and the appearance of an additional peroxidase. This can suggest that in Bryonia, auxin catabolism is hastened by mechanical stimulated peroxidase. In addition, Boyer et al.¹⁵ reported that lithium pre-treatment prevents both thigmomorphogenesis and appearance of specific cathodic isoperoxidase in Bryonia plants subjected to MIS. This is give further credence to the possibility that the peroxidase-auxin system is involved in Bryonia thigmomorphogenesis. In addition, ethylene increases peroxidase activity which reduces the auxin content in the tissue to a level low enough not to support normal growth. We have evidence that decrease of auxin level contribute to mechanism leading to tomato internode inhibition subjected to mechanical stress.Growth inhibition has been suggested to be the result of tissues lignification.⁶ As the initial enzyme in the monolignol biosynthesis pathway, PAL has a direct influence on lignin accumulation.¹⁶ The characteristics of lignin differ among cell wall tissues and plant organs.¹⁷ It comprises polyphenolic polymers derived from the oxidative polymerization of different monolignols, including p-coumaryl, coniferyl and sinapyl alcohols via a side pathway of phenylalanine metabolism leading to lignin synthesis.¹⁸ The increase in lignin content in the rubbed tomato internode could be a response mechanism to mechanical damage caused by rubbing.³ It is known that plants create a natural barrier that includes lignin and suberin synthesis, components directly linked to support systems.^19,20The increase in lignin content of rubbed tomato internode³ is paralleled by a rise in CAD activity and whilst such direct proportionality between CAD activity and lignin accumulation does not always agree with the results in the literature, it clearly is responding in ways similar to those of the other enzymes in the pathway.²¹Mechanical stress-induced membrane depolarization would generate different species of free radicals and peroxides, which in turn initiate lipid peroxidation.²² The degradation of cell membranes is suggested to bring about rapid changes in ionic flux, especially release of K⁺ which would result in an enhanced endogenous Ca/K ratio and in leakage of solutes, among them electron donors such as ascorbic acid and phenolic substances. The increased intracellular relative calcium level activated secretion of basic peroxidases²³ into the free space where, in association with the electron donors and may be with the circulating IAA, they eliminate the peroxides, and facilitated binding of basic peroxidases to membrane structures allowing a role as 1-aminocyclopropane-1-carboxylic acid (ACC)-oxidases. The resulting IAA and ACC oxidase-mediated changes in ethylene production²⁴ would further induce (this time through the protein synthesis machinery) an increase in activity of phenylalanine ammonia-lyase and peroxidases. The resulting lignification and cell wall rigidification determines the growth response of tomato internode to the mechanical stress.