A survey of the East Palaearctic Lycosidae (Araneae). 9. Genus Xerolycosa Dahl, 1908 (Evippinae)

Three species of Xerolycosa: Xerolycosa nemoralis (Westring, 1861), Xerolycosa miniata (C.L. Koch, 1834) and Xerolycosa mongolica (Schenkel, 1963), occurring in the Palaearctic Region are surveyed, illustrated and redescribed. Arctosa mongolica Schenkel, 1963 is removed from synonymy with Xerolycosa nemoralis and transferred to Xerolycosa, and the new combination Xerolycosa mongolica (Schenkel, 1963) comb. n. is established. One new synonymy, Xerolycosa undulata Chen, Song et Kim, 1998 syn.n. from Heilongjiang = Xerolycosa mongolica (Schenkel, 1963), is proposed. In addition, one more new combination is established, Trochosa pelengena (Roewer, 1960) comb. n., ex Xerolycosa.     

Patterns of Ecosystem Metabolism in the Tonle Sap Lake,Cambodia with Links to Capture Fisheries

The Tonle Sap Lake in Cambodia is a dynamic flood-pulsed ecosystem that annually increases its surface area from roughly 2,500 km² to over 12,500 km² driven by seasonal flooding from the Mekong River. This flooding is thought to structure many of the critical ecological processes, including aquatic primary and secondary productivity. The lake also has a large fishery that supports the livelihoods of nearly 2 million people. We used a state-space oxygen mass balance model and continuous dissolved oxygen measurements from four locations to provide the first estimates of gross primary productivity (GPP) and ecosystem respiration (ER) for the Tonle Sap. GPP averaged 4.1±2.3 g O₂ m⁻³ d⁻¹ with minimal differences among sites. There was a negative correlation between monthly GPP and lake level (r = 0.45) and positive correlation with turbidity (r = 0.65). ER averaged 24.9±20.0 g O₂ m⁻³ d⁻¹ but had greater than six-fold variation among sites and minimal seasonal change. Repeated hypoxia was observed at most sampling sites along with persistent net heterotrophy (GPP<ER), indicating significant bacterial metabolism of organic matter that is likely incorporated into the larger food web. Using our measurements of GPP, we calibrated a hydrodynamic-productivity model and predicted aquatic net primary production (aNPP) of 2.0±0.2 g C m⁻² d⁻¹ (2.4±0.2 million tonnes C y⁻¹). Considering a range of plausible values for the total fisheries catch, we estimate that fisheries harvest is an equivalent of 7–69% of total aNPP, which is substantially larger than global average for marine and freshwater systems. This is likely due to relatively efficient carbon transfer through the food web and support of fish production from terrestrial NPP. These analyses are an important first-step in quantifying the resource pathways that support this important ecosystem.     

Opioid receptor pharmacological chaperones act by binding and stabilizing newly synthesized receptors in the endoplasmic reticulum

Accumulating evidence has indicated that membrane-permeable G protein-coupled receptor ligands can enhance cell surface targeting of their cognate wild-type and mutant receptors. This pharmacological chaperoning was thought to result from ligand-mediated stabilization of immature receptors in the endoplasmic reticulum (ER). In the present study, we directly tested this hypothesis using wild-type and mutant forms of the human delta-opioid receptor as models. ER-localized receptors were isolated by expressing the receptors in HEK293 cells under tightly controlled tetracycline induction and blocking their ER export with brefeldin A. The ER-retained delta-opioid receptor precursors were able to bind [(3)H]diprenorphine with high affinity, and treatment of cells with an opioid antagonist naltrexone led to a 2-fold increase in the number of binding sites. After removing the transport block, the antagonist-mediated increase in the number of receptors was detectable at the cell surface by flow cytometry and cell surface biotinylation assay. Importantly, opioid ligands, both antagonists and agonists, were found to stabilize the ER-retained receptor precursors in an in vitro heat inactivation assay and the treatment enhanced dissociation of receptor precursors from the molecular chaperone calnexin. Thus, we conclude that pharmacological chaperones facilitate plasma membrane targeting of delta-opioid receptors by binding and stabilizing receptor precursors, thereby promoting their release from the stringent ER quality control.     

A SURVEY OF THE HOLARCTIC LINYPHIIDAE （ARANEAE）, OF THE ERIGONINE GENUS ZORNELLA JACKSON, 1932

The Holarctic erigonid genus Zornella has been surveyed. Four spedes are recognized in this genus, two Palaearctic： Z. aultrigera （L. Koch, 11879） ＆ Z. orientalis sp. nov., and two Nearcfic： Z. arrnata （Banks, 1906） ＆ Z. ayptodon Chamherlin, 1920. It is demouslrated that neither nearcfic species is agnspedtic with Z. atltrigera as was thought by Holm and other authors. Z. sp. nov. is describcd from northeastern Siberia. All of the species are illustrated and their distributions mapped.