Impact of ocean acidification on antimicrobial activity in gills of the blue mussel (Mytilus edulis).

Here, we aimed to investigate potential effects of ocean acidification on antimicrobial peptide (AMP) activity in the gills of Mytilus edulis, as gills are directly facing seawater and the changing pH (predicted to be reduced from ∼8.1 to ∼7.7 by 2100). The AMP activity of gill and haemocyte extracts was compared at pH 6.0, 7.7 and 8.1, with a radial diffusion assay against Escherichia coli. The activity of the gill extracts was not affected by pH, while it was significantly reduced with increasing pH in the haemocyte extracts. Gill extracts were also tested against different species of Vibrio (V. parahaemolyticus, V. tubiashii, V. splendidus, V. alginolyticus) at pH 7.7 and 8.1. The metabolic activity of the bacteria decreased by ∼65-90%, depending on species of bacteria, but was, as in the radial diffusion assay, not affected by pH. The results indicated that AMPs from gills are efficient in a broad pH-range. However, when mussels were pre-exposed for pH 7.7 for four month the gill extracts presented significantly lower inhibit of bacterial growth. A full in-depth proteome investigation of gill extracts, using LC-Orbitrap MS/MS technique, showed that among previously described AMPs from haemocytes of Mytilus, myticin A was found up-regulated in response to lipopolysaccharide, 3 h post injection. Sporadic occurrence of other immune related peptides/proteins also pointed to a rapid response (0.5-3 h p.i.). Altogether, our results indicate that the gills of blue mussels constitute an important first line defence adapted to act at the pH of seawater. The antimicrobial activity of the gills is however modulated when mussels are under the pressure of ocean acidification, which may give future advantages for invading pathogens.

Accumulation of manganese in the haemolymph, nerve and muscle tissue of Nephrops norvegicus (L.) and its effect on neuromuscular performance.

Exposure of Norway lobsters, Nephrops norvegicus (L.) for 3 weeks to manganese concentrations, (5 & 10 mg Mn l(-1) (90-180 microM)), led to its accumulation in various body tissues. The highest concentration was in nerve tissue (brain and abdominal ganglia) which had up to 6 times (on wet wt. basis) the manganese concentration of the exposure concentration, whereas the haemolymph accumulated 3 times and the muscle tissue only 0.5 times the exposure concentration. In the haemolymph the manganese was bound mainly to protein, predominantly (80-90%) to the respiratory protein haemocyanin, as the concentration was 14 times higher in the protein fraction than in the supernatant. Manganese did not substitute for copper in the haemocyanin, as the copper concentration remained constant despite the manganese exposure. The possibility that manganese exposure induced neurotoxic effects sufficient to reduce neuromuscular performance was assessed from the kinematics of free tail-flip swimming, and from measures of the forces produced by abdominal movements in tethered animals. No significant reduction in tail flip velocity or flexion force, but a significant reduction in the maximum post-flip extension force was found. No correlation was found between the manganese concentration in a single tissue or different fractions of the haemolymph and the post-flip extension, except for a weak negative correlation with the manganese concentration in the abdominal ganglion. The ecophysiological implications of these results are discussed.

Beyond the feminisation of poverty: gender-aware poverty reduction.

PIP: There must be an awareness of gender issues in poverty reduction programs. For example, program efforts that direct aid to the promotion of labor intensive employment options disregard women's already overburdened work regime. Public expenditures to benefit the poor, such as primary education or reformed agricultural extension, may be based on the assumption that men and women will benefit equally, yet there is often gender bias in the delivery of services. One recommendation is to target female headed households in budget-constrained anti-poverty programs. One of the few examples of such programs provides urban female household heads in Chile with employment training, housing, health care, child care, and legal aid services. Causes of female headship vary, and a simple correlation with poverty is not always the case. Well-intentioned women-in-development credit programs in Ghana and Bangladesh have been "hijacked" by men. Programs to address gender discrimination only among the poor may overlook other oppressed women. In India gender discrimination is often greatest among women in wealthy households. Programs must offer more than economic resources, they must help women stretch traditional gender boundaries and obtain skills such as literacy or financial management. They must help women organize collectively to protest injustices and achieve institutional reforms.^ieng

Capillary neoformation in the rat heart--stereological studies on papillary muscles in hypertrophy and physiologic growth.

Stereological investigations on myocardial capillaries provided evidence that the common estimator of capillarity, the capillary density (i.e., number of capillary profiles per unit transverse sectional area), underestimates the true capillary supply since the capillary axes are not oriented perfectly in parallel to the myofiber axes. Recently, we studied the "true" capillarity, i.e., the length density of capillaries (LV = capillary length per capillary volume), in some experimental models of cardiac hypertrophy which have been published elsewhere. It has been shown that LV decreases in renovascular hypertension, but is maintained in physical exercise and after chronic thyroxin application. However, the growth pattern of capillaries in hypertrophic hearts has not yet been analyzed. In the present paper it is demonstrated that important information on the capillary network can be derived from the two-dimensional capillary-to-fiber ratios (2D CFR: capillary profiles per myofiber profiles in transverse sections) and from the three-dimensional capillary-to-fiber ratios (3D CFR: capillary length per unit myofiber length). Increase in both suggests neoformation of additional capillary branches in parallel connection. Retrospective analysis of the quantitative data indicates that in hypertrophy induced by physical exercise or by chronic thyroxin application capillary neoformation in parallel connection counterbalances increase of oxygen diffusion distance due to myofiber enlargement. In renovascular hypertension, capillary neoformation in parallel connection does not occur. Studies on normal growth indicated both a slight decrease of LV of capillaries, as well as a continuous neoformation of additional capillary branches.

Development of early brainstem projections to the tail spinal cord of Xenopus.

Horseradish peroxidase (HRP) was used to determine the sequence in which axons from different brain neurons reach the tail spinal cord during embryonic and early larval development of Xenopus laevis. Brainstem cells of several classes project to the tail at these stages: mesencephalic reticulospinal neurons of the nucleus of the medial longitudinal fasciculus, a variety of other reticulospinal neurons, vestibulospinal neurons, and a group of median basal cells which may be raphe neurons. Among the reticulospinal neurons the paired Mauthner cells are the most prominent. They and caudally situated reticular neurons are the first to label with HRP applied to the tail spinal cord (stage 37). Vestibulospinal and other reticular neurons begin to label next (stage 39), followed by mesencephalic and then median basal neurons (stage 41). Except for the Mauthner cells, the number of labeled cells belonging to each neuron class increases gradually as development proceeds.