Shifts in microbial and chemical patterns within the marine sponge Aplysina aerophoba during a disease outbreak

The microbial community composition in affected and unaffected portions of diseased sponges and healthy control sponges of Aplysina aerophoba was assessed to ascertain the role of microbes in the disease process. Sponge secondary metabolites were also examined to assess chemical shifts in response to infection. The microbial profile and aplysinimine levels in unaffected tissue near the lesions closely reflected those of healthy sponge tissue, indicating a highly localized disease process. DGGE detected multiple sequences that were exclusively present in diseased sponges. Most notably, a Deltaproteobacteria sequence with high homology to a coral black band disease strain was detected in all sponge lesions and was absent from all healthy and unaffected regions of diseased sponges. Other potential pathogens identified by DGGE include an environmental Cytophaga strain and a novel Epsilonproteobacteria strain with no known close relatives. The disease process also caused a major shift in prokaryote community structure at a very high taxonomic level. Using 16S rRNA gene sequence analysis, only the diseased sponges were found to contain sequences belonging to the Epsilonproteobacteria and Firmicutes, and there was a much greater number of Bacteroidetes sequences within the diseased sponges. In contrast, only the healthy sponges contained sequences corresponding to the cyanobacteria and 'OP1' candidate division, and the healthy sponges were dominated by Chloroflexi and Gammaproteobacteria sequences. Overall bacterial diversity was found to be considerably higher in diseased sponges than in healthy sponges. These results provide a platform for future cultivation-based experiments to isolate the putative pathogens from A. aerophoba and perform re-infection trials to define the disease aetiology.     

Fluorescence polarization: a novel indicator of cardiomyocyte contraction

The changes measured in intracellular fluorescein fluorescence polarization (IFFP) are used as a new tool for tracing cytoplasmic effects during contractile cycles of cardiac myocytes (1-2-day-old rat hearts), in addition to the established Ca(2+) monitoring and/or videometric methods of tracking cell-shortening. This novel method was found to be non-intrusive to the contraction cycles. The decay of the transient IFFP signal (from 0.220+/-0.01 to 0.170+/-0.013) seems to be closely related to the extended phase of contractile activation. This fact was further supported when Ca(2+) exchanger inhibitor was introduced and significantly decreased (90%) the rate of beats of contraction and IFFP, but not the Ca(2+) beat rate changes. This result suggests that the IFFP indicator is probably associated with the physiological activation, rather than with Ca(2+) alterations. The IFFP measure monitors the average of effective changes in the micro-viscosity of the cytoplasm protein matrix, associated with cellular activation.     

The importance of micro-habitat in the breeding of Barn Owls Tyto alba

Capsule?Habitat parameters associated with 706 Barn Owl (Tyto alba) nesting boxes in Israel were analysed. Pairs bred in 259 of the boxes. The intensity of agricultural practices at nestbox sites were shown to have only a weak effect on aspects of Barn Owl breeding in this region.     

Methotrexate enhances the anti-inflammatory effect of CF101 via up-regulation of the A3 adenosine receptor expression

Methotrexate (MTX) exerts an anti-inflammatory effect via its metabolite adenosine, which activates adenosine receptors. The A3 adenosine receptor (A3AR) was found to be highly expressed in inflammatory tissues and peripheral blood mononuclear cells (PBMCs) of rats with adjuvant-induced arthritis (AIA). CF101 (IB-MECA), an A3AR agonist, was previously found to inhibit the clinical and pathological manifestations of AIA. The aim of the present study was to examine the effect of MTX on A3AR expression level and the efficacy of combined treatment with CF101 and MTX in AIA rats. AIA rats were treated with MTX, CF101, or both agents combined. A3AR mRNA, protein expression and exhibition were tested in paw and PBMC extracts from AIA rats utilizing immunohistochemistry staining, RT-PCR and Western blot analysis. A3AR level was tested in PBMC extracts from patients chronically treated with MTX and healthy individuals. The effect of CF101, MTX and combined treatment on A3AR expression level was also tested in PHA-stimulated PBMCs from healthy individuals and from MTX-treated patients with rheumatoid arthritis (RA). Combined treatment with CF101 and MTX resulted in an additive anti-inflammatory effect in AIA rats. MTX induced A2AAR and A3AR over-expression in paw cells from treated animals. Moreover, increased A3AR expression level was detected in PBMCs from MTX-treated RA patients compared with cells from healthy individuals. MTX also increased the protein expression level of PHA-stimulated PBMCs from healthy individuals. The increase in A3AR level was counteracted in vitro by adenosine deaminase and mimicked in vivo by dipyridamole, demonstrating that receptor over-expression was mediated by adenosine. In conclusion, the data presented here indicate that MTX induces increased A3AR expression and exhibition, thereby potentiating the inhibitory effect of CF101 and supporting combined use of these drugs to treat RA.     

Differential effects of unnatural sialic acids on the polysialylation of the neural cell adhesion molecule and neuronal behavior.

In this study we have examined how unnatural sialic acids can alter polysialic acid expression and influence the adhesive properties of the neural cell adhesion molecule (NCAM). Unnatural sialic acids are generated by metabolic conversion of synthetic N-acyl mannosamines and are typically incorporated into cell-surface glycoconjugates. However, N-butanoylmannosamine and N-pentanoylmannosamine are effective inhibitors of polysialic acid (PSA) synthesis in stably transfected HeLa cells expressing NCAM and the polysialyltransferase STX. These cells were used as substrates to examine the effect of inhibiting PSA synthesis on the development of neurons derived from the chick dorsal root ganglion. N-butanoylmannosamine blocked polysialylation of NCAM and significantly reduced neurite outgrowth comparable with enzymatic removal of PSA by endoneuraminidases. As a result, neurite outgrowth was similar to that observed for non-polysialylated NCAM. In contrast, previous studies have shown that N-propanoyl sialic acid (SiaProp), generated from N-propanoylmannosamine, is readily accepted by polysialyltransferases and permits the extension of poly(SiaProp) on NCAM. Despite being immunologically distinct, poly(SiaProp) can promote neurite outgrowth similarly to natural polysialic acid. Thus, subtle structural differences in PSA resulting from the incorporation of SiaProp residues do not alter the antiadhesive properties of polysialylated NCAM.     

Conditional association between melanism and personality in Israeli Barn Owls

Capsule Boldness defines the extent to which animals are willing to take risks in the presence of a predator. Late, but not early, in the breeding season, Israeli nestling Barn Owls displaying larger black feather spots were more docile, feigned death longer and had a lower breathing rate when handled than smaller-spotted nestlings. Larger-spotted breeding females were less docile if heavy but more more docile if light. The covariation between personality (boldness vs. timid) and melanin-based colouration is therefore conditional on environmental factors.     

Comparison of conventional culture and PCR methods for the detection of Legionella pneumophila in water

A comparative assessment of conventional culture and nucleic acid techniques in the detection of Legionella pneumophila in seeded tap water samples was performed, using bacterial concentrations ranging from 994 to 0·015 cfu ml⁻¹. Different filtration and centrifugation protocols were evaluated. The results permitted the development of a tentative algorithm for the detection of legionellae in tap water. Samples should first be analysed using PCR methods. In the event of quantitative data and bacterial strains for epidemiologic typing being required, the same sample, or a greater volume of the sample, if positive with PCR, can be re-tested by filtration through polycarbonate membranes followed by plating a homogenate of the filter. If samples are found to be negative with PCR, they can be re-analysed in greater volumes by filtration through polycarbonate membranes followed by direct placing of the filter on culture media, to allow detection of very low numbers of bacteria. This protocol should be validated in the field before it can be routinely implemented.     

Primary cultures of human caudate nucleus

It is possible to grow functional primary dissociated cultures and explants from stereotactic biopsies of human parkinsonian caudate nuclei. Two major classes of cells were identified on morphological grounds. The culture cells appear to be stimulated by an unidentified soluble factor(s) obtained from human fetal neuronal cells in vitro. Culture of primary neuronal and glial cells from human adult cerebral nuclei seems to be a useful tool for several research purposes and in particular for studying both trophic factor action and target effects on afferent neurons for prospective human brain grafting.     

Movement ecology and sex are linked to barn owl microbial community composition

The behavioural ecology of host species is likely to affect their microbial communities, because host sex, diet, physiology, and movement behaviour could all potentially influence their microbiota. We studied a wild population of barn owls (Tyto alba) and collected data on their microbiota, movement, diet, size, coloration, and reproduction. The composition of bacterial species differed by the sex of the host and female owls had more diverse bacterial communities than their male counterparts. The abundance of two families of bacteria, Actinomycetaceae and Lactobacillaceae, also varied between the sexes, potentially as a result of sex differences in hormones and immunological function, as has previously been found with Lactobacillaceae in the microbiota of mice. Male and female owls did not differ in the prey they brought to the nest, which suggests that dietary differences are unlikely to underlie the differences in their microbiota. The movement behaviour of the owls was associated with the host microbiota in both males and females because owls that moved further from their nest each day had more diverse bacterial communities than owls that stayed closer to their nests. This novel result suggests that the movement ecology of hosts can impact their microbiota, potentially on the basis of their differential encounters with new bacterial species as the hosts move and forage across the landscape. Overall, we found that many aspects of the microbial community are correlated with the behavioural ecology of the host and that data on the microbiota can aid in generating new hypotheses about host behaviour.     

Homoclinic chaos in a model of natural selection

 We modify a simple mathematical model for natural selection originally formulated by Robert M. May in 1983 by permitting one homozygote to have a larger selective advantage when rare than the other, and show that the new model exhibits dynamical chaos. We determine an open region of parameter space associated with homoclinic points, and prove that there are infinite sequences of period-doubling bifurcations along selected paths through parameter space. We also discuss the possibility of chaos arising from imbalance in the homozygote fitnesses in more realistic biological situations, beyond the constraints of the model. Received 3 February 1995; received in revised form 1 November 1995