Draft Genome Sequences of Strains of Pasteurella multocida Isolated from the United Kingdom and the United States

Pasteurella multocida is a major pathogen of farm animals and has worldwide distribution. Here we report the draft genome sequences of four strains that were isolated from animals in the United Kingdom and the United States and represent pathogenic and commensal presentation of the bacterium

Organization of the spermatozoon of Agriolimax reticulatus , the grey field slug (Pulmonata, Stylommatophora)

Mature spermatozoa from the seminal vesicles of adult Agriolimax reticulatus have been studied by means of phase contrast and electron microscopy; sperm were either live, or sectioned or mounted whole and shadowed with gold. The cell is of the typical pulmonate sperm type with a simple acrosome and a spiral nucleus comprising the head, and a tail which is ensheathed along its entire length by mitochondrion. The 9 peripheral fibrils of the axial complex show no indication of a double nature. Within the spermatheca or “gametolytic gland” breakdown of sperm occurs; the nucleus and axial fibre bundle of the flagellum survive the longest. The complexity of the flagellum and the relative simplicity of the acrosome are discussed in light of the ecology of the spermatozoa. Many problems concerning the functional physiology of the sperm organelles remain to be investigated.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47658/1/441_2004_Article_BF00335402.pd

Aggregation of Sea Urchin Phagocytes Is Augmented In Vitro by Lipopolysaccharide

Development of protocols and media for culturing immune cells from marine invertebrates has not kept pace with advancements in mammalian immune cell culture, the latter having been driven by the need to understand the causes of and develop therapies for human and animal diseases. However, expansion of the aquaculture industry and the diseases that threaten these systems creates the need to develop cell and tissue culture methods for marine invertebrates. Such methods will enable us to better understand the causes of disease outbreaks and to develop means to avoid and remedy epidemics. We report a method for the short-term culture of phagocytes from the purple sea urchin, Strongylocentrotus purpuratus, by modifying an approach previously used to culture cells from another sea urchin species. The viability of cultured phagocytes from the purple sea urchin decreases from 91.6% to 57% over six days and phagocyte morphology changes from single cells to aggregates leading to the formation of syncytia-like structures. This process is accelerated in the presence of lipopolysaccharide suggesting that phagocytes are capable of detecting this molecular pattern in culture conditions. Sea urchin immune response proteins, called Sp185/333, are expressed on the surface of a subset of phagocytes and have been associated with syncytia-like structures. We evaluated their expression in cultured phagocytes to determine their possible role in cell aggregation and in the formation of syncytia-like structures. Between 0 and 3 hr, syncytia-like structures were observed in cultures when only similar to 10% of the cells were positive for Sp185/333 proteins. At 24 hr, similar to 90% of the nuclei were Sp185/333-positive when all of the phagocytes had aggregated into syncytia-like structures. Consequently, we conclude that the Sp185/333 proteins do not have a major role in initiating the aggregation of cultured phagocytes, however the Sp185/333 proteins are associated with the clustered nuclei within the syncytia-like structures

Effects of Cu/Zn Superoxide Dismutase (sod1) Genotype and Genetic Background on Growth, Reproduction and Defense in Biomphalaria glabrata

Resistance of the snail Biomphalaria glabrata to the trematode Schistosoma mansoni is correlated with allelic variation at copper-zinc superoxide dismutase (sod1). We tested whether there is a fitness cost associated with carrying the most resistant allele in three outbred laboratory populations of snails. These three populations were derived from the same base population, but differed in average resistance. Under controlled laboratory conditions we found no cost of carrying the most resistant allele in terms of fecundity, and a possible advantage in terms of growth and mortality. These results suggest that it might be possible to drive resistant alleles of sod1 into natural populations of the snail vector for the purpose of controlling transmission of S. mansoni. However, we did observe a strong effect of genetic background on the association between sod1 genotype and resistance. sod1 genotype explained substantial variance in resistance among individuals in the most resistant genetic background, but had little effect in the least resistant genetic background. Thus, epistatic interactions with other loci may be as important a consideration as costs of resistance in the use of sod1 for vector manipulation

Resistance to Schistosoma mansoni is correlated with the number of spreading granulocytes in Biomphalaria glabrata

Molluscan internal defenses rely heavily on circulating hemocytes. In most cases, encounters with large foreign bodies result in recognition by hemocytes followed by spreading of these defense cells over the object’s surface. The resulting encapsulation concentrates the force of the hemocytes’ assault on the foreign object. B. glabrata snail lines obtained by self-fertilization of isolated 13-16-R1 [Oregon] individuals have yielded multiple inbred families in which genes are fixed at ~88% of the loci. Among the phenotypic traits that we have measured in 20 of these families are susceptibilities of snails to the PR1 [Oregon] strain of Schistosoma mansoni, and hematocrits of quickly spreading granulocytes present in the hemolymph.  Higher numbers of these cells predict a snail phenotype that is resistant to S. mansoni infection. Both resistant and susceptible snails are found in families with intermediate hematocrits. We infer that within the parental 13-16-R1 population hemocyte numbers are varied. When sufficiently numerous, a snail’s hemocytes can generally prevent parasitic infection. At lower hematocrits, a more complex set of variables interact to determine the outcome of an infection

Will all scientists working on snails and the diseases they transmit please stand up?

Copyright © 2012 Adema et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.No abstract available