Gill area, permeability and Na+ ,K+ -ATPase activity as a function of size and salinity in the blue crab, Callinectes sapidus

Juvenile blue crabs, Callinectes sapidus, extensively utilize oligohaline and freshwater regions of the estuary. With a presumptively larger surface-area-to-body weight ratio, juvenile crabs could experience osmo- and ionoregulatory costs well in excess of that of adults. To test this hypothesis, crabs ranging over three orders of magnitude in body weight were acclimated to either sea water (1,000 mOsm) or dilute sea water (150 mOsm), and gill surface area, water and sodium permeabilities (calculated from the passive efflux of 3H2O and 22Na+), gill Na+, K+ -ATPase activity and expression were measured. Juveniles had a relatively larger gill surface area; weight-specific gill surface area decreased with body weight. Weight-specific water and sodium fluxes also decreased with weight, but not to the same extent as gill surface area; thus juveniles were able to decrease gill permeability slightly more than adults upon acclimation to dilute media. Crabs < 5 g in body weight had markedly higher activities of gill Na+ ,K+ -ATPase than crabs > 5 g in both posterior and anterior gills. Acclimation to dilute medium induced increased expression of Na+, K+ -ATPase and enzyme activity, but the increase was not as great in juveniles as in larger crabs.The increased weight-specific surface area for water gain and salt loss for small crabs in dilute media presents a challenge that is incompletely compensated by reduced permeability and increased affinity of gill Na+, K+ -ATPase for Na+. Juveniles maintain osmotic and ionic homeostasis by the expression and utilization of extremely high levels of gill Na+, K+ -ATPase, in posterior, as well as in anterior, gills.     

Sequence specificity incompletely defines the genome-wide occupancy of Myc

Adult house flies, Musca domestica L., are mechanical vectors of more than 100 devastating diseases that have severe consequences for human and animal health. House fly larvae play a vital role as decomposers of animal wastes, and thus live in intimate association with many animal pathogens. We have sequenced and analyzed the genome of the house fly using DNA from female flies. The sequenced genome is 691 Mb. Compared with Drosophila melanogaster, the genome contains a rich resource of shared and novel protein coding genes, a significantly higher amount of repetitive elements, and substantial increases in copy number and diversity of both the recognition and effector components of the immune system, consistent with life in a pathogen-rich environment. There are 146 P450 genes, plus 11 pseudogenes, in M. domestica, representing a significant increase relative to D. melanogaster and suggesting the presence of enhanced detoxification in house flies. Relative to D. melanogaster, M. domestica has also evolved an expanded repertoire of chemoreceptors and odorant binding proteins, many associated with gustation. This represents the first genome sequence of an insect that lives in intimate association with abundant animal pathogens. The house fly genome provides a rich resource for enabling work on innovative methods of insect control, for understanding the mechanisms of insecticide resistance, genetic adaptation to high pathogen loads, and for exploring the basic biology of this important pest. The genome of this species will also serve as a close out-group to Drosophila in comparative genomic studies.     

Microsatellite markers revealed moderate genetic diversity and population differentiation of moso bamboo (<Emphasis Type="Italic">Phyllostachys edulis</Emphasis>)—a primarily asexual reproduction species in China

As an ecologically and economically important endemic bamboo species, moso (Phyllostachys edulis) has been widely distributed in Southern China. In the paper, 20 fluorescently labeled microsatellite markers were used to evaluate the genetic structure of Ph. edulis including 34 representative populations (803 individuals) covering the geographic range in China. Moderate genetic diversity (H?= 0.376) and differentiation (Gst?= 0.162) were detected at the species level, with the majority of genetic diversity occurring within populations (84.55%). Bayesian model-based structure analysis and sNMF/ANLS-AS method revealed the presence of two and three clusters. When K?=?2, majority of populations (except SX) were clustered together (C1). It implied that SX, known as an introduced and isolated founder population, significantly differed from other populations for distinct environmental selection and allele mutation with the proof of scarce outcrossing and relatively high frequency of private allele. While K?=?3, two subgroups (C1a of 18 populations and C1b of 14 populations) were detected within C1. The C1b displayed as a belt-shape region with an east-west direction. It coincided with the extremely high artificial selection in C1b (lower genetic diversity than that of C1a) due to the intensive plantation in the last four decades. Our results implied that the population protection and germplasm collection of moso bamboo should be not only from representative populations in Zhejiang, Jiangxi, Fujian, and other places with intensive cultivation in the east of China, but from populations with high level of gene and genotypic diversity in the west (e.g., HN5, GD1, GZ2, YN1, and SX).