Simultaneous quanitative determination of secondary metabolites ofAspergillus ochraceus by TLC

A simple TLC method for the quanitative determination of mellein, 4-hydroxy-mellein, penicillic acid, ochratoxin A, B, α and β is described. Application of this technique permits metabolic studies of the influence of different factors on the formation ofAspergillus ochraceus metabolites.     

Effect of ionic liquids alkyl chain length on horseradish peroxidase thermal inactivation kinetics and activity recovery after inactivation

The effects of different alkyl chain lengths of ionic liquids 1-ethyl-, 1-butyl- and 1-hexyl-3-methylimidazolium chloride, on the catalytic activity, thermal stability and deactivation kinetics of horseradish peroxidase were studied in the temperature range of 45–85 °C. The presence of 1-ethyl- and 1-butyl-ionic liquids up to 25 % (w/v) did not affect significantly the enzyme activity at 25 °C, whereas the addition of 1-hexyl-solvent resulted in lower activity of enzyme. Typical biphasic deactivation profiles were obtained and adequately fitted by a bi-exponential equation. When increasing ionic liquids concentration up to 25 % (w/v), the second phase of deactivation became more prominent, till leading to apparent first-order kinetics. Occurrence of activity regain, following thermal deactivation was found, reaching up 60–80 % of the initial activity, especially in 1-hexyl-3-methylimidazolium chloride. Activity regain was particularly noticeable in the first phase of deactivation. Temperature sensitivity of the Soret band maxima indicated that the enzyme prepared in buffer or 1-hexyl-3-methylimidazolium chloride had similar conformational changes in the haem region, but no correlations were found with activity decrease.     

Virus‐induced gene silencing in transgenic plants: transgene silencing and reactivation associate with two patterns of transgene body methylation

We used bisulfite sequencing to study the methylation of a viral transgene whose expression was silenced upon plum pox virus infection of the transgenic plant and its subsequent recovery as a consequence of so‐called virus‐induced gene silencing (VIGS). VIGS was associated with a general increase in the accumulation of small RNAs corresponding to the coding region of the viral transgene. After VIGS, the transgene promoter was not methylated and the coding region showed uneven methylation, with the 5′ end being mostly unmethylated in the recovered tissue or mainly methylated at CG sites in regenerated silenced plants. The methylation increased towards the 3′ end, which showed dense methylation in all three contexts (CG, CHG and CHH). This methylation pattern and the corresponding silenced status were maintained after plant regeneration from recovered silenced tissue and did not spread into the promoter region, but were not inherited in the sexual offspring. Instead, a new pattern of methylation was observed in the progeny plants consisting of disappearance of the CHH methylation, similar CHG methylation at the 3′ end, and an overall increase in CG methylation in the 5′ end. The latter epigenetic state was inherited over several generations and did not correlate with transgene silencing and hence virus resistance. These results suggest that the widespread CG methylation pattern found in body gene bodies located in euchromatic regions of plant genomes may reflect an older silencing event, and most likely these genes are no longer silenced.     

Effects of fungus inoculation and salt stress on physiology and biochemistry of in vitro grapevines: Emphasis on sugar composition changes by FT-IR analyses

The impacts of salt stress and inoculation in in vitro grapevine (Vitis vinifera L.) growth, nutrient accumulation, osmoregulation, photosynthesis and membrane integrity were evaluated. One month exposure to 100 mM NaCl as well as to inoculation with Phaeomoniella chlamydospora reduced relative growth rate (RGR) and induced senescence in grapevine plants, shown by: (1) decrease of Ψ_π without osmoregulation, (2) decrease of chlorophyll content and fluorescence, (3) loss of membrane integrity and (4) nutritional disorders. To assess putative changes in structural and/or non-structural carbohydrates induced by these two stress conditions, alcohol insoluble residues from the roots, stems and leaves were also characterised by FT-IR and GC with respect to the sugar composition. The referred organs were distinguished based on: (1) higher proportion of uronic acid residues in leaves which diagnose the presence of pectic polysaccharides (wavenumbers 1100, 1150 and 1018 cm^?1 in FT-IR spectra), (2) higher proportion of xylose and glucose on stems and FT-IR spectra diagnostic of xylose-rich polysaccharides (1041 cm^?1) and cellulose (1060 cm^?1), (3) higher proportion of glucose residues, xylose and arabinose on roots and a FT-IR spectra characteristic of xylose-rich polysaccharides (1041 cm^?1). The main alterations induced by salt stress and inoculation were more visible in leaves, where the content of uronic acid decreased showing that changes in cell wall composition occurred, mostly at the pectic fraction. Besides, an accumulation of insoluble glucose was found, and FT-IR spectra showed that this glucose-based material was starch (maximum absorption at 998 cm^?1), accumulated as a non-specific response to salt stress and P. chlamydospora inoculation.     

Maintaining contact with bucks does not induce refractoriness to the male effect in seasonally anestrous female goats

A study was performed to determine if complete separation between sexes is a pre-requisite to stimulate sexual activity of anovulatory female goats by male exposure in mid-anestrus when reproductive activity is greatly inhibited. The response to the male was studied in anovulatory goats which had either been in contact with bucks before the stimulation (n = 22; CONT), or totally isolated from bucks (n = 22; ISOL). At the time of male exposure, the bucks from the CONT groups were removed and females of both groups (CONT and ISOL) were divided into two subgroups (n = 11) exposed to novel bucks (n = 1 per subgroup), either in sexual rest (sexually inactive; SI) or in which sexual activity had been induced by a photoperiodic treatment (sexually active; SA). The sexual behavior of the SA bucks during the first 5 days of stimulation was greater than that of SI bucks (P < 0.01). Regardless of whether females had been (82%) or not (91%) exposed to bucks before teasing, most goats stimulated by SA males displayed estrous behavior and ovulation in the first 15 days following stimulation, whereas no female from the two subgroups exposed to SI bucks showed estrous behavior and only one of them ovulated (P < 0.02). These results indicate that previous isolation of seasonally anovulatory goats from bucks is not required to stimulate their reproductive activity by the male effect, if sexually active bucks are used.     

Matching and Symmetry in the Frequency Recognition Curve of the Poison Frog Epipedobates trivittatus

In territorial species, males use signals to advertise territory ownership to other males. In species with acoustic communication, masking interference by heterospecific signals may impede male–male communication and affect the reproductive success of males. Frogs are thought to minimize masking interference by using species‐specific frequency channels for communication. For this strategy to work, a frequency match is expected between the advertisement call and the auditory sensitivity. A previous field study on the Amazonian frog Epipedobates femoralis supported this prediction, but also revealed an asymmetric decrease in the probability of male reaction towards synthetic calls. That males of E. femoralis reacted less towards low‐frequency (compared with high‐frequency) calls was interpreted as a mechanism that reduces masking interference by E. trivittatus, a species calling within a lower, partially overlapping, frequency range. If this hypothesis holds, then males of E. trivittatus should exhibit the opposite asymmetry pattern, i.e. react less towards high‐frequency (compared with low‐frequency) calls. We tested this prediction by conducting 25 playback experiments on 22 males of E. trivittatus. Male phonotactic reaction towards synthetic calls of various frequency values was evaluated as a binary variable (the male either approached or not the loudspeaker), by measuring the latency until first jump, and by calculating the linear approaching speed. As in E. femoralis, the maximum probability of positive reaction was matched to the call frequency. Against our expectations, the response curve was symmetric. We discuss whether these results reflect a lack of selective pressures, or a compromise between natural selection and physiological constraints on the shape of the frequency recognition curves.     

Heterogeneity in Patient-Reported Outcomes following Low-Intensity Mental Health Interventions: A Multilevel Analysis

Background

Variability in patient-reported outcomes of psychological treatments has been partly attributed to therapists – a phenomenon commonly known as therapist effects. Meta-analytic reviews reveal wide variation in therapist-attributable variability in psychotherapy outcomes, with most studies reporting therapist effects in the region of 5% to 10% and some finding minimal to no therapist effects. However, all except one study to date have been conducted in high-intensity or mixed intervention groups; therefore, there is scarcity of evidence on therapist effects in brief low-intensity psychological interventions.

Objective

To examine therapist effects in low-intensity interventions for depression and anxiety in a naturalistic setting.

Data and Analysis

Session-by-session data on patient-reported outcome measures were available for a cohort of 1,376 primary care psychotherapy patients treated by 38 therapists. Outcome measures included PHQ-9 (sensitive to depression) and GAD-7 (sensitive to general anxiety disorder) measures. Three-level hierarchical linear modelling was employed to estimate therapist-attributable proportion of variance in clinical outcomes. Therapist effects were evaluated using the intra-cluster correlation coefficient (ICC) and Bayesian empirical predictions of therapist random effects. Three sensitivity analyses were conducted: 1) using both treatment completers and non-completers; 2) a sub-sample of cases with baseline scores above the conventional clinical thresholds for PHQ-9 and GAD-7; and 3) a two-level model (using patient-level pre- and post-treatment scores nested within therapists).

Results

The ICC estimates for all outcome measures were very small, ranging between 0% and 1.3%, although most were statistically significant. The Bayesian empirical predictions showed that therapist random effects were not statistically significantly different from each other. Between patient variability explained most of the variance in outcomes.

Conclusion

Consistent with the only other study to date in low intensity interventions, evidence was found to suggest minimal to no therapist effects in patient-reported outcomes. This draws attention to the more prominent source of variability which is found at the between-patient level.     

Alleles and haplotypes of the interleukin 10 gene polymorphisms are associated with risk of developing acute coronary syndrome in Mexican patients

Inflammation plays an important role in the pathogenesis of atherosclerosis and acute coronary syndromes (ACS). Interleukin-10 (IL-10) is a potent anti-inflammatory cytokine that mediates the inflammatory process. The objective of the present study was to evaluate the role of IL-10 gene polymorphisms as susceptibility markers for ACS in Mexican patients. IL-10 promoter polymorphisms (positions -1082, -819, and -592) were analyzed by 5' exonuclease TaqMan genotyping assays in 389 ACS patients and 302 healthy controls. ACS patients showed increased frequencies of IL-10-592 C allele and CC genotype when compared to healthy controls (pC=0.0006, OR=1.48 and pC=0.022, OR=1.56, respectively), whereas the frequencies of the A allele and AA genotype were decreased in patients (pC=0.0006, OR=0.68 and pC=0.006, OR=0.57, respectively). When the distribution of IL-10-592 genotypes was analyzed separately in women and men (patients and healthy controls), a different distribution of alleles and genotypes was observed only in the group of men. In this case, increased frequency of C allele (pC=0.004, OR=1.46) and decreased frequencies of A allele (pC=0.004, OR=0.68) and AA genotype (pC=0.023, OR=0.56) were observed in the group of patients when compared to healthy controls. Multiple logistic analyses by gender showed that male individuals with IL-10-592CC+AC genotypes had 3.54-fold increased risk of developing ACS than individuals with AA genotype (p<0.001). The analysis of linkage disequilibrium showed one (ACC) increased haplotype in patients as compared to healthy controls. The results suggest that IL-10 gene polymorphisms could be involved in the risk of developing ACS in the Mexican population.     

Use of FT-IR spectroscopy as a tool for the analysis of polysaccharide food additives

This work purposes the characterisation of food additive polysaccharides such as starch, glucomannan and carrageenan by the use of the information of the principal components of the FT-IR spectra in the 1200–800 cm⁻¹ wavenumber region. The application of a PCA to this spectral region showed that several features could be obtained: (a) Separation between Glc and Gal, both monomeric and polymeric, and identification of their characteristic wavenumbers. (b) Identification of the specific absorbance wavenumbers for sucrose, Fru, Ara, and Man. (c) Distinction of pectic polysaccharides from the remaining carbohydrate samples. (d) Separation within κ-, ι-, and λ-carrageenans. These results show that the FT-IR spectroscopy in the 1200–800 cm⁻¹ wavenumber region can be a very reliable technique for food authentication of polysaccharide-based additives and be used for a quick screening of polysaccharides used as additives in foodstuffs.