Effects of tumour necrosis factor alpha (TNFalpha) on Mytilus haemocytes: role of stress-activated mitogen-activated protein kinases (MAPKs)

BACKGROUND INFORMATION: Many studies indicate that innate immunity in invertebrates can be modulated by a cytokine network like in vertebrates. In molluscs, the immune response is carried out by circulating haemocytes and soluble haemolymph factors. In the present study, the effects of heterologous TNFalpha (tumour necrosis factor alpha) on cell signalling and function in the haemocytes of the bivalve Mytilus galloprovincialis Lam. were investigated. RESULTS AND CONCLUSIONS: Addition of TNFalpha in the absence of haemolymph serum [in ASW (artificial sea water)] induced cellular stress, as indicated by lysosomal destabilization, and decreased phagocytosis; on the other hand, in the presence of serum, TNFalpha did not affect lysosomal stability and even stimulated phagocytosis. TNFalpha induced rapid phosphorylation of the stress-activated p38 and JNK (c-Jun N-terminal kinase) MAPKs (mitogen-activated protein kinases); both effects were persistent in ASW but transient in serum. Activation of p38 and JNKs in mediating the effects of TNFalpha was confirmed by the use of specific MAPK inhibitors. Moreover, flow cytometric analysis indicated that TNFalpha in the presence of serum induced transient phosphatidylserine exposure on the haemocyte surface, evaluated as annexin V binding; in ASW, the cytokine resulted in a stable increase in the percentage of both annexin- and propidium iodide-positive cells, indicating possible apoptotic/necrotic processes. The results indicate that TNFalpha can affect the function of bivalve haemocytes through conserved transduction pathways involving stress-activated MAPKs and suggest that the haemocyte response to the cytokine is influenced by soluble haemolymph components.     

Interference of Mycotoxins with Prenatal Development of the Mouse

The prenatal effects of mycotoxins were investigated in GBA mice given by stomach tube a single dose of either aflatoxin B1 (4 mg/kg), ochratoxin A (8 mg/kg) or zearalenone (20 mg/kg) on pregnancy day 8 or 9. Aflatoxin caused foetal anomalies (exencephaly, open eyes, and protrusion of intestines) after exposure on gestation day 8 but not on day 9. The effects (increased prenatal mortality, reduced foetal growth, and a wide variety of malformations) caused by ochratoxin were much more severe and occurred after treatment on either of the 2 days of gestation. Among the spectrum of malformations, predominantly involving the craniofacial complex and the axial skeleton, the most striking was the total aplasia/dysplasia of the upper facial structures. These defects were always accompanied by exencephaly and anophthalmia. Zearalenone caused no effects. It is concluded that of the 3 mycotoxins screened with the technique used, ochratoxin is the most potent teratogen in mice.     

Quantifying ‘normal’ shoulder muscle activity during abduction

The purpose of this experiment was to obtain electromyographic (EMG) activity from a sample of healthy shoulders to allow a reference database to be developed and used for comparison with pathological shoulders. Temporal and intensity shoulder muscle activation characteristics during a coronal plane abduction/adduction movement were evaluated in the dominant healthy shoulder of 24 subjects. Surface and intramuscular fine wire electrodes recorded EMG activity from 15 shoulder muscles (deltoid × 3, trapezius × 3, subscapularis × 2, latissimus dorsi, pectoralis major, pectoralis minor, supraspinatus, infraspinatus, serratus anterior and rhomboids) at 2000 Hz for 10 s whilst each subject performed 10 dynamic coronal plane abduction/adduction movements from 0° to 166° to 0° with a light dumbbell. Results revealed that supraspinatus (?.102 s before movement onset) initiated the movement with middle trapezius (?.019 s) and middle deltoid (?.014 s) also activated before the movement onset. Similar patterns were also found in the time of peak amplitude and %MVC with a pattern emerging where the prime movers (supraspinatus and middle deltoid) were among the first to reach peak amplitude or display the highest %MVC values. In conclusion, the most reproducible patterns of activation arose from the more prime mover muscle sites in all EMG variables analysed and although variability was present, there emerged ‘invariant characteristics’ that were considered ‘normal’ for this group of non pathological shoulders. The authors believe that the methodology and certain parts of the analysis in this study can be duplicated and used by future researchers who require a reference database of muscle activity for use as a control group in comparisons to their respective pathological shoulder group.     

Evidence for Introduction Bottleneck and Extensive Inter-Gene Pool (Mesoamerica x Andes) Hybridization in the European Common Bean (Phaseolus vulgaris L.) Germplasm

Common bean diversity within and between Mesoamerican and Andean gene pools was compared in 89 landraces from America and 256 landraces from Europe, to elucidate the effects of bottleneck of introduction and selection for adaptation during the expansion of common bean (Phaseolus vulgaris L.) in Europe. Thirteen highly polymorphic nuclear microsatellite markers (nuSSRs) were used to complement chloroplast microsatellite (cpSSRs) and nuclear markers (phaseolin and Pv-shatterproof1) data from previous studies. To verify the extent of the introduction bottleneck, inter-gene pool hybrids were distinguished from “pure” accessions. Hybrids were identified on the basis of recombination of gene pool specific cpSSR, phaseolin and Pv-shatterproof1 markers with a Bayesian assignments based on nuSSRs, and with STRUCTURE admixture analysis. More hybrids were detected than previously, and their frequency was almost four times larger in Europe (40.2%) than in America (12.3%). The genetic bottleneck following the introduction into Europe was not evidenced in the analysis including all the accessions, but it was significant when estimated only with “pure” accessions, and five times larger for Mesoamerican than for Andean germplasm. The extensive inter-gene pool hybridization generated a large amount of genotypic diversity that mitigated the effects of the bottleneck that occurred when common bean was introduced in Europe. The implication for evolution and the advantages for common bean breeding are discussed.     

Xylose anaerobic conversion by open-mixed cultures

Xylose is, after glucose, the dominant sugar in agricultural wastes. In anaerobic environments, carbohydrates are converted into volatile fatty acids and alcohols. These can be used as building blocks in biotechnological or chemical processes, e.g., to produce bioplastics. In this study, xylose fermentation by mixed microbial cultures was investigated and compared with glucose under the same conditions. The product spectrum obtained with both substrates was comparable. It was observed that, in the case of xylose, a higher fraction of the carbon was converted into catabolic products (butyrate, acetate, and ethanol) and the biomass yield was approximately 20% lower than on glucose, 0.16 versus 0.21 Cmol X/Cmol S. This lower yield is likely related to the need of an extra ATP during xylose uptake. When submitted to a pulse of glucose, the population cultivated on xylose could instantaneously convert the glucose. No substrate preference was observed when glucose and xylose were fed simultaneously to the continuously operated bioreactor.     

Physicochemical and mechanical characterization of galactomannan from Mimosa scabrella: Effect of drying method

The galactomannan from Mimosa scabrella Bentham was extracted on a pilot plant scale and dried either by vacuum oven (GVO) or by spray-drier (GSD) to evaluate the effect of the drying technique on the powder quality and its applicability as excipient in solid dosage forms. The analysis by high performance size exclusion chromatography (HPSEC) coupled to multiangle laser light scattering (MALLS) suggests that both products behave as semi-flexible polymers, although the GSD showed more aggregation at molecular level (～10%) and higher chain stiffness (Lp 9.1 nm). TG and DSC analysis showed weight loss event with peak at 299.7 and 311.9 °C to GVO and GSD, respectively, as well and higher ash content for GSD sample, in both inert and oxidant atmosphere. The X-ray diffraction confirmed the amorphous nature of both galactomannans although GVO showed high crystallinity. The GSD showed lower density (1.009 g/cm³), higher cohesiveness (repose angle 35.5°, compressibility 32.2% and absence of flow), smaller and more spherical particles than GVO sample, both with high polydispersion. As vacuum oven-drying resulted in a like fibrous material, spray-drying appears as an alternative method easy to extrapolate in industry, requiring a glidant incorporation to improve the powder flowability.