Aflatoxin concentrations in chilies vary depending on variety

Aflatoxin (AF) contamination was determined in 40 chili samples, representing 3 varieties from Punjab, Pakistan, by HPLC with fluorescence detection. Total AF were determined in varieties Longi (n = 15), Wonder hot (n = 12), and Skyline 1 (n = 13), and the concentrations were high in some samples. AF were detected in 9 (60%), 8 (67%), and 7 (54%) of Longi, Wonder hot, and Skyline 1 samples, respectively; concentration ranged from 4.7 to 34.6, 1.0 to 14.3, and 7.8 to 15.6 μg/kg, respectively. The percentage of samples greater than the European Union statutory limit for AFB₁ and total AF in spices were 53% and 53%, 53% and 8%, and 53% and 38% for Longi, Wonder hot, and Skyline 1, respectively. Significant differences at α < 0.05 between mean concentration of AF in Longi (15.9 ± 0.6 μg/kg) and Wonder hot (5.8 ± 0.3 μg/kg) were determined. In conclusion, choosing the variety demonstrating the lowest AF concentration from various chili samples will assist in improving product quality. This preferred variety is Wonder Hot as described herein.     

Qualitative and quantitative characteristics of rotavirus-specific CD8 T cells vary depending on the route of infection

CD8 T-cell response provides an important defense against rotavirus, which infects a variety of systemic locations in addition to the gut. Here we investigated the distribution, phenotype, and function of rotavirus-specific CD8 T cells in multiple organs after rotavirus infection initiated via the intranasal, oral, or intramuscular route. The highest level of virus-specific CD8 T cells was observed in the Peyer's patches of orally infected mice and in the lungs of intranasally infected animals. Very low levels of virus-specific CD8 T cells were detected in peripheral blood or spleen irrespective of the route of infection. Rotavirus-specific CD8 T cells from Peyer's patches of orally infected mice expressed high levels of CCR9, while CXCR6 and LFA-1 expression was associated with virus-specific CD8 T cells in lungs of intranasally infected mice. Oral infection induced the highest proportion of gamma interferon(-) CD107a/b(+) CD8 T cells in Peyer's patches. When equal numbers of rotavirus-specific CD8 T cells were transferred into Rag-1 knockout mice chronically infected with rotavirus, the donor cells derived from Peyer's patches of orally infected mice were more efficient than those derived from lungs of intranasally infected animals in clearing intestinal infection. These results suggest that different routes of infection induce virus-specific CD8 T cells with distinct homing phenotypes and effector functions as well as variable abilities to clear infection.     

The type and yield of lipopolysaccharide from symbiotically deficient rhizobium lipopolysaccharide mutants vary depending on the extraction method

At least 18 lipopolysaccharide (LPS) extraction methods are available, and no single method is universally applicable. Here, the LPSs from four R.etli, one R.leguminosarum bv. trifolii mutant, 24AR, and the R.etli parent strain, CE3, were isolated by hot phenol/water (phi;/W), and phenol/EDTA/triethylamine (phi/EDTA/TEA) extraction. The LPS in various preparations was quantified, analyzed by deoxycholate polyacrylamide gel electrophoresis (DOC-PAGE), and by immunoblotting. These rhizobia normally have two prominent LPS forms: LPS I, which has O-polysaccharide, and LPS II, which has none. The LPS forms obtained depend on the method of extraction and vary depending on the mutant that is extracted. Both methods extract LPS I and LPS II from CE3. The phi/EDTA/TEA, but not the phi/W, method extracts LPS I from mutants CE358 and CE359. Conversely, the phi;/W but not the phi;/EDTA/TEA method extracts CE359 LPS V, an LPS form with a truncated O-polysaccharide. phi/EDTA/TEA extraction of mutant CE406 gives good yields of LPS I and II, while phi/W extraction gives very small amounts of LPS I. The LPS yield from all the strains using phi/EDTA/TEA extraction is fairly consistent (3-fold range), while the yields from phi/W extraction are highly variable (850-fold range). The phi/EDTA/TEA method extracts LPS I and LPS II from mutant 24AR, but the phi/W method partitions LPS II exclusively into the phenol phase, making its recovery difficult. Overall, phi/EDTA/TEA extraction yields more forms of LPS from the mutants and provides a simpler, faster, and less hazardous alternative to phi/W extraction. Nevertheless, it is concluded that careful analysis of any LPS mutant requires the use of more than one extraction method.     

Pharmacological effects of oral saikosaponin a may differ depending on conditions of the gastrointestinal tract

Saikosaponin a and its 8 derivatives, structural isomers and their monoglycosides and aglycones, which were formed in the gastrointestinal tract with their fecal contents depending on food intake, showed different effects on protein synthesis by rat hepatocytes in primary culture. Saikosaponin a and its monoglycoside and aglycone were detectable in plasma of rats when saikosaponin a was orally administered. Pharmacological effects of saikosaponin a when orally administered may differ depending on conditions of the gastrointestinal tract.     

Efficiency of biofeedback training of functional state regulation depending on individual psychophysiological characteristics

The psychophysiological characteristics of the subjects (emotional stability, autonomic lability, tension of autonomic regulation of cardiac activity, and EEG characteristics) were estimated. The efficiency of relaxation regulation training with the use of biofeedback (with the electrocutaneous impedance as a BF signal) was studied. Before and after BF training, an electrophysiological experiment was carried out, namely, a “relaxation test” without BF support. The test consisted of three situations: background, relaxation, and the state after coming out of relaxation. During the test, EEGs of different cortical areas (α bands) and autonomic indices were recorded. A short-term memory test was carried out with the purpose of controlling changes in the functional status. It has been shown that even a short training cycle of five sessions in most cases provided relaxation and improvement in self-regulation, accompanied by improvement of the mnestic activity. The effect of individual psychophysiological characteristics on the success of BF training has been established. A high autonomic lability, a high level of nonspecific cortex activity, as well as a dysfunction of the frontal-thalamic system, should be regarded as factors preventing effective self-regulation training.     

Changes in plasma angiotensin-converting enzyme activity and noradrenaline responses to long-term nitric oxide inhibition vary depending on their basal values in chickens

In this study, we investigated the effects of N(omega)-nitro-L-arginine (L-NNA) on arterial blood pressure (BP), plasma noradrenaline (NA) and adrenaline (A) levels and angiotensin-converting enzyme (ACE) activity. L-NNA was applied with tap water (1 mg/ml) from the 3rd to the 8th week of age (group L-NNA1). In Experiment 1, long-term L-NNA application increased BP compared to the control group (group C1) (L-NNA1 = 131.4 +/- 6.3, n = 6; C1 = 82.7 +/- 4.7 mm Hg, n = 7) but decreased plasma noradrenaline and adrenaline levels and ACE activity (NA levels: C1 = 15.5 +/- 0.8, n = 7; L-NNA1 = 8.6 +/- 0.5 ng/ml, n = 7; A levels: C1 = 15.5 +/- 0.8, n = 7; L-NNA1 = 6.0 +/- 0.5 ng/ml, n = 7; ACE activities: C1 = 87.3 +/- 3.1, n = 6; L-NNA1 = 46.2 +/- 1.9 U/l, n = 5). On the other hand, in Experiment 2 (carried out under the same conditions and in age-matched chickens), blood pressure, plasma noradrenaline levels and ACE activity were found to differ in the control group (C2) (BP = 141.4 +/- 15.5 mm Hg, n = 7; NA = 1.1 +/- 0.4 ng/ml, n = 7; ACE = 57.2 +/- 5.3 U/l, n = 7) as compared to C1, while plasma adrenaline levels were similar. In this series, long-term L-NNA application (group L-NNA2) did not change the BP, but surprisingly increased noradrenaline and ACE values (values of L-NNA2: BP = 165.7 +/- 15.6 mm Hg, n = 7; NA = 9.3 +/- 1.3 ng/ml, n = 8; ACE = 149.4 +/- 16 U/l, n = 8) while decreasing plasma adrenaline levels. L-arginine addition to L-NNA treatment completely reversed plasma noradrenaline and ACE activity values. These results indicate the modulatory activity of an L-arginine-NO pathway on adrenaline release as well as on the renin-angiotensin system in chickens.     

Diphenylamine-based retinoid antagonists: regulation of RAR and RXR function depending on the N-substituent

Based upon the structure-activity relationships of diphenylamine derivatives with retinoid synergistic activity (RXR agonists), novel diphenylamine derivatives with a long alkyl chain (9a and 9b) or a benzyl group (10a-f) as the N-substituent were designed and synthesized. All the synthesized compounds dose-dependently inhibited HL-60 cell differentiation induced by 3.3×10(-10)M Am80. Among them, compound 10f showed the most potent inhibitory activity, and the mechanism was shown, by means of transactivation assay for RARs and RXRs, to involve antagonism against RARs. The N-substituent of the diphenylamine skeleton plays an important role in determining the receptor selectivity for RARs or RXRs, as well as the agonist or antagonist nature of the activity.     

Microtubules may harden or soften cells, depending of the extent of cell distension

Experimental data show that disruption of microtubules causes cells to either become stiffer or softer. Current understanding of these behaviors is based on several different mechanisms, each of which can account for only stiffening or softening. In this study we offer a model that can explain both these features. The model is based on the cellular tensegrity idea. Key premises of the model are that cell shape stability is secured through pre-existing mechanical stress (prestress) borne by the actin cytoskeletal network, and that this prestress is partly balanced by cytoskeletal microtubules and partly by the extracellular matrix. Thus, disturbance of this balance would affect cell deformability. The model predicts that disruption of microtubules causes an increase or a decrease in cell stiffness, depending on the extent to which microtubules participate in balancing the prestress which, in turn, depends on the extent of cell spreading. In highly spread cells microtubules have a minor and negative contribution to cell stiffness, whereas in less spread cells their contribution is positive and substantial. Since in their natural habitat cells seldom exhibit highly spread forms, the above results suggest that the contribution of microtubules to cell deformability cannot be overlooked.     

The mixotroph Ochromonas tuberculata may invade and suppress specialist phago- and phototroph plankton communities depending on nutrient conditions

Mixotrophic organisms combine light, mineral nutrients, and prey as supplementary resources. Based on theoretical assumptions and field observations, we tested experimentally the hypothesis that mixotrophs may invade established plankton communities depending on the trophic status of the system, and investigated possible effects on food web structure, species diversity, and nutrient dynamics. To test our hypothesis, we inoculated the mixotrophic nanoflagellate Ochromonas tuberculata into established planktonic food webs, consisting of specialist phototrophs, specialist phagotrophs, and bacteria at different supplies of soluble inorganic nutrients and dissolved organic carbon. Oligotrophic systems facilitated the invasion of O. tuberculata in two different ways. First, the combination of photosynthesis and phagotrophy gave mixotrophs a competitive advantage over specialist phototrophs and specialist phagotrophs. Second, low nutrient supplies supported the growth of small plankton organisms that fell into the food size spectrum of mixotrophs. Conversely, high nutrient supplies prevented O. tuberculata from successfully invading the food webs. Two important conclusions were derived from our experiments. First, in contrast to a paradigm of ecology, specialization may not necessarily be the most successful strategy for survival under stable conditions. Indeed, the use of several resources with lower efficiency can be an equally, or even more, successful strategy in nature. Second, when limiting nutrients promote the growth of bacterio- and picophytoplankton, invading mixotrophs may have a habitat-ameliorating effect for higher trophic levels, gauged in terms of food quantity and quality. Using given resources more efficiently, O. tuberculata generated higher biomasses and expressed an increased nutritional value for potential planktivores, due to decreased cellular carbon to phosphorus (C:P) ratios compared to specialized plankton taxa. Our findings may help to explain why energy transfer efficiency between phytoplankton and higher trophic levels is generally higher in oligotrophic systems than in nutrient rich environments.     

Transient global ischemia in rat brain promotes different NMDA receptor regulation depending on the brain structure studied

The mRNA expression of the major subunits of N-methyl-d-aspartate receptors (NR1, NR2A and NR2B) following ischemia–reperfusion was studied in structures with different vulnerabilities to ischemic insult in the rat brain. The study was performed using quantitative real-time PCR on samples from 3-month-old male Sprague–Dawley rats after global transient forebrain ischemia followed by 48 h of reperfusion. Expression of NMDA receptor subunits mRNAs decreased significantly in all structures studied in the injured animals as compared to the sham-operated ones. The hippocampal subfields (CA1, CA3 and dentate gyrus) as well as the caudate-putamen, both reported to be highly ischemic-vulnerable structures, showed outstandingly lower mRNA levels of NMDA receptor subunits than the cerebral cortex, which is considered a more ischemic-resistant structure. The ratios of the mRNA levels of the different subunits were analyzed as a measure of the NMDA receptor expression pattern for each structure studied. Hippocampal areas showed changes in NMDA receptor expression after the insult, with significant decreases in the NR2A with respect to the NR1 and NR2B subunits. Thus, the NR1:NR2A:NR2B (1:1:2) ratios observed in the sham-operated animals became (2:1:4) in insulted animals. This modified expression pattern was similar in CA1, CA3 and the dentate gyrus, in spite of the different vulnerabilities reported for these hippocampal areas. In contrast, no significant differences in the expression pattern were observed in the caudate-putamen or cerebral cortex on comparing the sham-operated animals with the ischemia-reperfused rats. Our results support the notion that the regulation of NMDA receptor gene expression is dependent on the brain structure rather than on the higher or lower vulnerability of the area studied.     

Revisiting delta-6 desaturase regulation by C18 unsaturated fatty acids,depending on the nutritional status

Dietary polyunsaturated fatty acids (PUFA) play a key role in regulating delta-6 desaturase (D6D), the key enzyme for long-chain PUFA biosynthesis. Nevertheless, the extent of their effects on this enzyme remains controversial and difficult to assess. It has been generally admitted that C18 unsaturated fatty acids (UFAs) regulate negatively delta-6 desaturase (D6D). This inhibition has been evidenced in regard to a high glucose/fat free (HG/FF) diet used in reference. However, several nutritional investigations did not evidence any inhibition of desaturases when feeding fatty acids.Because the choice of the basal diet appeared to be of primary importance in such experiments, our goal was to reconsider the specific role of dietary UFAs on D6D regulation, depending on nutritional conditions. For that, sixteen adult Wistar rats were fed purified linoleic acid, α-linolenic acid or oleic acid, included in one of two diets at 4% by weight: an HG/FF or a high starch base (HS) where the pure UFAs replaced a mixed vegetable oil. Our results showed first that D6D specific activity was significantly greater when measured in presence of an HG/FF than with an HS/4% vegetable oil diet. Secondly, we found that linoleic and alpha-linolenic acids added to HG/FF reduced the specific activity of D6D. In contrast, when pure UFAs were added to an HS base, D6D specific activities remained unchanged or increased. Concordant results were obtained on D6D mRNA expression.Altogether, this study evidenced the importance of the nutritional status in D6D regulation by C18 UFAs: when used as control, HG/FF diet stimulates D6D compared with a standard control diet containing starch and 4% fats, leading to an overestimation of the D6D regulation by UFAs. Then, UFAs should be considered as repressors for unsaturated fatty acid biosynthesis only in very specific nutritional conditions.     

Neurotensin concentrations in rat striatum and nucleus accumbens: Further studies of their regulation

The possible influence of cholinergic and dopaminergic mechanisms on neurotensin-containing neurones was examined at two different levels; nucleus accumbens and striatum in the rat brain. The acute treatment with the anticholinergic drugs atropine and scopolamine increased neurotensin concentrations in the striatum and, in the former case, also in the nucleus accumbens. Subchronic administration of atropine resulted in tolerance to its neurotensin-elevating action within the accumbens, but not within the striatum. Combined treatment with submaximal doses of haloperidol and atropine resulted in increases in neurotensin content which were greater than those seen with either agent alone. This was true regardless of whether the drugs were administered acutely or subchronically. This observation demonstrated that the tolerance phenomena occurring after subchronic elozapine and fluperlapine were not attributable to their anticholinergic activity. The control of striatal and accumbal neurotensin content by antidopaminergic and anticholinergic drugs seemed to be quite specific: drugs with actions on noradrenergic, serotoninergic, GABA-ergic and opiate systems did not influence the neurotensin content in these two structures. Preliminary studies on the effects of haloperidol on neurotensin release from striatal slices in vitro and that of cycloheximide on haloperidol's effect in vivo, suggest a possible inhibitory action of dopamine receptor blockade on neurotensin release.     

The biomass quality of algae used for CO2 sequestration is highly species-specific and may vary over time

The utilization of microalgae to temporarily sequester CO₂ is a hot topic in algal biotechnology. Its association with biomass utilization is often proposed to increase economical revenues. Although C allocation patterns may determine the success or failure of such use of algae, the impact of elevated CO₂ on biomass quality has not been investigated systematically. In this study, four algae of different taxonomy and mode of inorganic carbon acquisition were subjected to a transition from low (390 μL L^?1) to elevated (1,000 μL L^?1) pCO₂. Fourier transform infrared spectroscopy, a rapid, nonextractive, and reliable technique, was used to attain the necessary information on all main organic pools concomitantly and with no need for extractive procedures. Cell organic composition was analyzed after 24 hours and 20 days since the transition. The responses were very species-specific, and the biomass quality was modified over time, indicating that species selection and monitoring of biomass are essential for an adequate control on the quality of the product. Although these concepts may have been in the mind of the illuminated algae users, the experimental evidence is essentially nonexisting. We intended to make a first step towards filling this gap in knowledge.     

Pyrophosphate may be involved in regulation of bacterial glycogen synthesis

Inorganic pyrophosphate is a potent inhibitor of the enzyme that catalyzes synthesis of the glucosyl donor for Escherichia coli glycogen synthesis, ADP-glucose pyrophosphorylase. The Ki is determined to be 40 microM and the substrate ATP, the activator, fructose 1,6-P2 or the allosteric inhibitor, AMP do not greatly affect the inhibition. PPi exhibits mixed type inhibition with the other substrate, glucose 1-P. The potential regulation of glycogen synthesis by PPi is discussed.