Electrophoretic Profile of the general proteins in the Green (Perna viridis Linnaeus) and the Brown (Perna indica Kuriakose & Nair) mussels.

The electrophoretic profiles of the general proteins and the selected enzymes (MDH and EST) were examined in the green mussel, P. viridis and the brown mussel P. indica and their suspected hybrids from South India. The protein and the enzyme profiles were distinctly different in the two species. The protein profiles in different tissues of the green and brown mussels were found tissue and species specific. The two species are genetically different. The protein and the enzyme profiles in the brown and suspected ‘brown type’ hybrids were similar and that of the green and the suspected ‘green type’ hybrids were also similar. The suspected hybrids may be the colour morphs of the respective species. Morphometric studies on these two species and the suspected hybrids also corroborated the above findings

Effect of moulting, eyestalk ablation, starvation and transportation on the immune response of the Indian spiny lobster, Panulirus homarus

The Indian spiny lobster, Panulirus homarus (Linnaeus 1758), is of great commercial importance and has a high demand in the internationalmarket.However, due to the lack of larval rearing technology, traders depend heavily on the wild-caught undersized lobsters that are normally maintained in impoundments for fattening. Overstocking and poormanagement of these holding and fattening systems can result in stress, which can eventually lead to disease outbreak. Crustaceans respond to these stress factors with their innate immune system, consisting of bothcellularand humoral factors

Genomic evidence of intraspecific recombination in sugarcane mosaic virus

The sugarcane mosaic virus (SCMV) of the genus potyvirus, which primarily affects maize, sugarcane, sorghum, abaca, and grasses, occurs worldwide and causes significant economic loss. Using the full genome sequences of SCMV and several recombination detection methods, in this study we report that recombination is the major driving force in the evolution and emergence of several new variants of SCMV. We reported eight highly significant (P < 0.001) recombination break points, majority of which are located within 6K1-VPg-NIaPro-NIb region, thus indicating a region for recombination hotspot. The observation of commonalities of same recombination events among the SCMV isolates between the countries (Spain and Mexico), and within the country (within China, and within Mexico), suggests common origin of the isolates in respective regions

Profound Differences in Virus Population Genetics Correspond to Protection from CD4 Decline Resulting from Feline Lentivirus Coinfection

CD4 decline is a hallmark of disease onset in individuals infected with Feline Immunodeficiency Virus (FIV) or Human Immunodeficiency Virus type 1 (HIV-1). Cats that are infected with a poorly replicating, apathogenic FIV (PLV) prior to exposure to a virulent FIV strain (FIVC) maintain CD4 numbers by mechanisms that are not correlated with a measurable adaptive immune response or reduction in circulating viral load. We employed population genetic approaches based on the 3′ portion of the viral genome to estimate the population structure of FIVC from single and dual infected cats. In dual infected cats, FIVC effective population size was decreased during the initial viral expansion phase, and after three weeks of infection, the population declined sharply. The FIVC population recovered to pre-bottleneck levels approximately seven weeks post-FIVC infection. However, the population emerging from the bottleneck in dual infected cats was distinct based on estimates of temporal population structure and substitution profiles. The transition to transversion rate ratio (κ) increased from early to late phases in dual infected cats due primarily to a decrease in transversions whereas in single infected cats, κ declined over time. Although one clone with extensive G to A substitutions, indicative of host cytidine deaminase editing, was recovered from a dual infected cat during the bottleneck, the post bottleneck population had an overall reduction in G to A substitutions. These data are consistent with a model of PLV-induced host restriction, putatively involving host DNA editing, that alters the dynamics of FIVC throughout the course of infection leading to disease attenuation

Adaptive evolution after duplication of penaeidin antimicrobial peptides

Penaeidin antimicrobial peptides in penaeid shrimps are an important component of their innate immune system that provides immunity against infection caused by several gram-positive bacteria and filamentous fungal species. Despite the knowledge on the identification and characterization of these peptides in penaeid shrimps, little is known about the evolutionary pattern of these peptides and the underlying genetic mechanisms that maintain high sequence diversities in the penaeidin gene family. Based on the phylogenetic analyses and maximum likelihood-based codon substitution analyses, here we present the convincing evidence that multiple copies of penaeidins have evolved by gene duplication, and positive Darwinian selection (adaptive evolution) is the likely cause of accelerated rate of amino acid substitutions among these duplicated genes.fisheries of the country has led to a remarkable increase in fish landings, the problem of by-catch and targeted juvenile fishing is ever increasing. The present analysis shows that the contribution in the form of annual average profit by various craft–gear combinations is often not sufficient to compensate the overall loss generated by the same to the fishery through the harvest of juvenile fishes. Even though the fishermen gain some transient economic incentives from the juveniles landed, the estimated economic loss calculated was at about US$ 19,445 million year−1 from the mechanised as well as motorised sector. Both intergenerational and conventional discounting was applied to show the net present value (NPV) of future loss due to juvenile fishing. Some of the less capital intensive gears also substantially contribute towards the economic deficit caused by juvenile fishing. We suggest that, while considering the ecosystem impacts of accidental by-catch and intentional juvenile fishing, the economic impacts also should be taken into account prior to formulating any management measures. The study provides an insight to the cost of juvenile fishing in a multi-species multi-gear fishery, where a homogeneous management system is ineffective. The possible causes of increased growth overfishing in the country and subsequent economic loss to the industry are also discussed

Ruminant-specific multiple duplication events of PRDM9 before speciation

The PR domains of human PRDM7 and PRDM9 are aligned with the corresponding sequences of each lineage. (PDF 96 kb

Isolation by Distance Explains Genetic Structure of Buggy Creek Virus, a Bird-Associated Arbovirus

Many of the arthropod-borne viruses (arboviruses) show extensive genetic variability and are widely distributed over large geographic areas. Understanding how virus genetic structure varies in space may yield insight into how these pathogens are adapted to and dispersed by different hosts or vectors, the relative importance of mutation, drift, or selection in generating genetic variability, and where and when epidemics or epizootics are most likely to occur. However, because most arboviruses tend to be sampled opportunistically and often cannot be isolated in large numbers at a given locale, surprisingly little is known about their spatial genetic structure on the local scale at which host/vector/virus interactions typically occur. Here, we examine fine-scale spatial structure of two sympatric lineages of Buggy Creek virus (BCRV, Togaviridae), an alphavirus transmitted by the ectoparasitic swallow bug (Oeciacus vicarius) to colonially nesting cliff swallows (Petrochelidon pyrrhonota) and invasive house sparrows (Passer domesticus) in North America. Data from 377 BCRV isolates at cliff swallow colony sites in western Nebraska showed that both virus lineages were geographically structured. Most haplotypes were detected at a single colony or were shared among nearby colonies, and pair-wise genetic distance increased significantly with geographic distance between colony sites. Genetic structure of both lineages is consistent with isolation by distance. Sites with the most genetically distinct BCRV isolates were occupied by large numbers of house sparrows, suggesting that concentrations of invasive sparrows may represent foci for evolutionary change in BCRV. Our results show that bird-associated arboviruses can show genetic substructure over short geographic distances

Isolation by Distance Explains Genetic Structure of Buggy Creek Virus, a Bird-Associated Arbovirus

Many of the arthropod-borne viruses (arboviruses) show extensive genetic variability and are widely distributed over large geographic areas. Understanding how virus genetic structure varies in space may yield insight into how these pathogens are adapted to and dispersed by different hosts or vectors, the relative importance of mutation, drift, or selection in generating genetic variability, and where and when epidemics or epizootics are most likely to occur. However, because most arboviruses tend to be sampled opportunistically and often cannot be isolated in large numbers at a given locale, surprisingly little is known about their spatial genetic structure on the local scale at which host/vector/virus interactions typically occur. Here, we examine fine-scale spatial structure of two sympatric lineages of Buggy Creek virus (BCRV, Togaviridae), an alphavirus transmitted by the ectoparasitic swallow bug (Oeciacus vicarius) to colonially nesting cliff swallows (Petrochelidon pyrrhonota) and invasive house sparrows (Passer domesticus) in North America. Data from 377 BCRV isolates at cliff swallow colony sites in western Nebraska showed that both virus lineages were geographically structured. Most haplotypes were detected at a single colony or were shared among nearby colonies, and pair-wise genetic distance increased significantly with geographic distance between colony sites. Genetic structure of both lineages is consistent with isolation by distance. Sites with the most genetically distinct BCRV isolates were occupied by large numbers of house sparrows, suggesting that concentrations of invasive sparrows may represent foci for evolutionary change in BCRV. Our results show that bird-associated arboviruses can show genetic substructure over short geographic distances

Ecological divergence of two sympatric lineages of Buggy Creek virus, an arbovirus associated with birds

Most arthropod-borne viruses (arboviruses) show distinct serological subtypes or evolutionary lineages, with the evolution of different strains often assumed to reflect differences in ecological selection pressures. Buggy Creek virus (BCRV) is an unusual RNA virus (Togaviridae, Alphavirus) that is associated primarily with a cimicid swallow bug (Oeciacus vicarius) as its vector and the Cliff Swallow (Petrochelidon pyrrhonota) and the introduced House Sparrow (Passer domesticus) as its amplifying hosts. There are two sympatric lineages of BCRV (lineages A and B) that differ from each other by .6% at the nucleotide level. Analysis of 385 BCRV isolates all collected from bug vectors at a study site in southwestern Nebraska, USA, showed that the lineages differed in their peak times of seasonal occurrence within a summer. Lineage A was more likely to be found at recently established colonies, at those in culverts (rather than on highway bridges), and at those with invasive House Sparrows, and in bugs on the outsides of nests. Genetic diversity of lineage A increased with bird colony size and at sites with House Sparrows, while that of lineage B decreased with colony size and was unaffected by House Sparrows. Lineage A was more cytopathic on mammalian cells than was lineage B. These two lineages have apparently diverged in their transmission dynamics, with lineage A possibly more dependent on birds and lineage B perhaps more a bug virus. The long-standing association between Cliff Swallows and BCRV may have selected for immunological resistance to the virus by swallows and thus promoted the evolution of the more bug-adapted lineage B. In contrast, the recent arrival of the introduced House Sparrow and its high competence as a BCRV amplifying host may be favoring the more bird-dependent lineage A

Phylogeographical Structure and Evolutionary History of Two Buggy Creek Virus Lineages in the Western Great Plains of North America

Buggy Creek virus (BCRV) is an unusual arbovirus within the western equine encephalitis complex of alphaviruses. Associated with cimicid swallow bugs (Oeciacus vicarius) as its vector and the cliff swallow (Petrochelidon pyrrhonota) and house sparrow (Passer domesticus) as its amplifying hosts, this virus is found primarily in the western Great Plains of North America at spatially discrete swallow nesting colonies. For 342 isolates collected in Oklahoma, Nebraska, Colorado, and North Dakota, from 1974 to 2007, we sequenced a 2076 bp region of the 26S subgenomic RNA structural glycoprotein coding region, and analyzed phylogenetic relationships, rates of evolution, demographical histories and temporal genetic structure of the two BCRV lineages found in the Great Plains. The two lineages showed distinct phylogeographical structure: one lineage was found in the southern Great Plains and the other in the northern Great Plains, and both occurred in Nebraska and Colorado. Within each lineage, there was additional latitudinal division into three distinct sublineages. One lineage is showing a long-term population decline. In comparing sequences taken from the same sites 8–30 years apart, in one case one lineage had been replaced by the other, and in the other cases there was little evidence of the same haplotypes persisting over time. The evolutionary rate of BCRV is in the order of 1.6–3.6 × 10–4 substitutions per site per year, similar to that estimated for other temperate-latitude alphaviruses. The phylogeography and evolution of BCRV could be better understood once we determine the nature of the ecological differences between the lineages