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.     

The cumulative impacts of anthropogenic stressors vary markedly along environmental gradients

Understanding the cumulative effects of multiple stressors on biodiversity is key to managing their impacts. Stressor interactions are often studied using an additive/antagonistic/synergistic typology, aimed at identifying situations where individual stressor effects are reduced or amplified when they act in combination. Here, we analysed variation in the family richness of stream macroinvertebrates in the groups Ephemeroptera, Plecoptera and Trichoptera (EPT) at 4658 sites spanning a 32° latitudinal range in eastern Australia in relation to two largely human-induced stressors, salinity and turbidity, and two environmental gradients, temperature and slope. The cumulative and interactive effect of salinity and turbidity on EPT family richness varied across the landscape and by habitat (edge or riffle) such that we observed additive, antagonistic and synergistic outcomes depending on the environmental context. Our findings highlight the importance of understanding the consistency of multiple stressor impacts, which will involve higher-order interactions between multiple stressors and environmental factors.     

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.     

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.     

Interactions among stressors may be weak: Implications for management of freshwater macroinvertebrate communities

Aim

Ecological models that do not account for interactions among stressors, if interactions are important, could be inaccurate and lead to inefficient conservation strategies. Conversely, if interactions are not important (i.e., stressors operate largely independently), then actions concentrating on a stressor‐by‐stressor basis would be warranted. Here, we investigated whether interactions among multiple stressors affected widely used indices of freshwater macroinvertebrate biodiversity, which are sensitive to environmental change at management‐relevant scales (i.e., reaches and catchments).

Location

State of Victoria, south‐eastern Australia.

Methods

We used a 7,418‐sample dataset for stream macroinvertebrates from 2,165 sites distributed over 237,630 km² for 20 years. We calculated the interactive effects on stream macroinvertebrates of stressors operating at different scales, namely vegetation loss at the catchment and reach scales and hydrological change and salinization at the local scale. The importance of interactions among multiple stressors was assessed by comparing the cross‐validated predictive performance of models with and without multiple stressor interaction terms.

Results

Cross‐validated models explained 31%–63% of the variation in the macroinvertebrate responses. The most important stressors were catchment vegetation loss (the proportion of remaining native vegetation cover) and salinity. The inclusion of interaction terms did not increase cross‐validated predictive performance, which indicates that there was little evidence that interactions among stressors were important for explaining variation in commonly used freshwater macroinvertebrate condition indices.

Main conclusions

Interactions among vegetation, salinity and hydrological change stressors may not always be of importance for determining patterns of stream macroinvertebrate biodiversity, so that such interactions may not necessarily be critical considerations for catchment and reach scale management, at least if based on these or comparable condition indices. The mitigation of the impacts of vegetation loss, salinization and hydrological change stressors one‐by‐one probably is sufficient to guide conservation activities and might be advantageous if socio‐political contexts make it difficult to address interactions among stressors.

     

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.     

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.