Carrying capacity for shorebirds during migratory seasons at the Jiuduansha Wetland, Yangtze River Estuary, China

The carrying capacity of food resources for migrating shorebirds was estimated at a stopover site in the Yangtze River Estuary during the two migratory seasons (spring and autumn). From March to May and September to November 2005, the macrobenthos resources of the Jiuduansha Wetland were investigated, and most of the macrobenthos species in the newly-formed shoal were found to be appropriate food for shorebirds. Biomass measurements showed that the total food resource was about 4541.20 kg AFDW (Ash-Free Dry Weight) in spring and about 2279.64 kg AFDW in autumn. Calculations were also done in the available habitats (intertidal bare mudflat and Scirpus × mariqueter/Scirpus triqueter zones) for the shorebirds. The food resources in the available areas were about 3429.03 kg AFDW in spring and about 1700.92 kg AFDW in autumn. Based on the classification (by lean weight, basic metabolic rate and body length) of the shorebird community, and using the energy depletion model, it was theorized that all of the food resources in the Jiuduansha Wetland could support about 3.5 million shorebirds during spring season and 1.75 million shorebirds during autumn season. The shorebird carrying capacities in terms of the available food were about 2.6 million and 1.3 million birds during the two respective migration seasons. Considering the effect of intake rate, the potential carrying capacity was about 0.13–0.26 million shorebirds in the study area. The main factor restricting use of the area by shorebirds was the scarcity of available habitats for roosting at high tide rather than availability of food supply. We recommend restoring some wading pools in the dense Phragmites australis and Spartina alterniflora zones for shorebirds to roost in, to improve shorebirds’ utilization efficiency of the resources in the Jiuduansha Wetland. __________ Translated from Acta Ecologica Sinica, 2007, 27 (1): 90–96 [译自:生态学报]     

急性心肌梗死患者冠状动脉病变严重性与脉压和脉压指数的关系

目的:探讨急性心肌梗死(AMI)患者冠状动脉病变严重程度与脉压和脉压指数的关系.方法:对185例AMI患者进行冠状动脉造影术,冠状动脉病变严重程度用冠状动脉病变支数和Gensini积分来表示,并测定收缩压(SBP)和舒张压(DBP)并计算脉压(PP)及脉压指数(PPI).结果:与脉压＜65mmHg的患者相比,脉压≥65mmHg的患者冠状动脉3支血管病变的患病率和Gensini积分显著增高(P＜0.01).与PPI＜0.500的患者相比,PPI≥0.500的患者冠状动脉3支血管病变的患病率和Gensini积分亦显著增高(P＜0.01).结论:PP和PPI与AMI患者冠状动脉病变程度密切相关,在临床上具有指导作用.     

A review of recent advances in the study of early angiosperms from northeastern China

The last 10 years (1998–2007) were very productive and important in the study of early angiosperms in northeastern China. The new discoveries of the earliest well-documented records of angiosperms such as Archaefructus, as well as Hyrcantha decussata (= Sinocarpus decussatus), provided fresh knowledge for better understanding the primitive characters of the ancient angiosperms and also their aquatic (or wet) habitat and their herbaceous nature. Some new approaches such as the combination of molecular and morphological characters joined together to place Archaefructus in the angiosperm phylogenetic framework. These fossils demonstrate that we should expect more ancient angiosperms to be found in the pre-Cretaceous which will continue to add important new understanding to the nature of the origin and evolution of the angiosperms.     

Trophic functional groups and trophic levels of the macrobenthic community at the eastern tidal flat of Lingkun Island, China

A total of 33 taxa, including 21 families, 8 classes and 7 phyla, were found at the eastern tidal flat of Lingkun Island, Wenzhou Bay. Most of them were mollusks, crustaceans and polychaetes. The species numbers found at 3 tidal flats (high, middle and low) were 25, 30 and 14, respectively. It was shown that the high tidal flat had the highest value of diversity indices, followed by middle and low tidal flats. The species belonged to 5 different trophic functional groups: Phytophagous, Camivorous, Omnivorous, Planktophagous and Detritivorous in qualitative samplings. Then 3, 8, 5, 3 and 2 species belonged to Planktophagous, Phytophagous, Camivorous, Omnivorous and Detritivorous groups, respectively, in quantitative samplings. The density and species number of each functional group did not display seasonal variation by the two-way ANOVA method. Regardless of seasonal variation, density of the Phytophagous group and Camivorous group had distinct difference among different zones of tidal flats, and the species number of the Phytophagous group and Omnivorous group had obvious difference among different zones of tidal flats. Results show that there was variation of functional groups among habitats. Change in components of the macrobenthic community reflected different food sources in different zones of tidal flats.     

Sialoadhesin expressed on IFN-induced monocytes binds HIV-1 and enhances infectivity

Background

HIV-1 infection dysregulates the immune system and alters gene expression in circulating monocytes. Differential gene expression analysis of CD14⁺ monocytes from subjects infected with HIV-1 revealed increased expression of sialoadhesin (Sn, CD169, Siglec 1), a cell adhesion molecule first described in a subset of macrophages activated in chronic inflammatory diseases.

Methodology/Principal Findings

We analyzed sialoadhesin expression on CD14⁺ monocytes by flow cytometry and found significantly higher expression in subjects with elevated viral loads compared to subjects with undetectable viral loads. In cultured CD14⁺ monocytes isolated from healthy individuals, sialoadhesin expression was induced by interferon-α and interferon-γ but not tumor necrosis factor-α. Using a stringent binding assay, sialoadhesin-expressing monocytes adsorbed HIV-1 through interaction with the sialic acid residues on the viral envelope glycoprotein gp120. Furthermore, monocytes expressing sialoadhesin facilitated HIV-1 trans infection of permissive cells, which occurred in the absence of monocyte self-infection.

Conclusions/Significance

Increased sialoadhesin expression on CD14⁺ monocytes occurred in response to HIV-1 infection with maximum expression associated with high viral load. We show that interferons induce sialoadhesin in primary CD14⁺ monocytes, which is consistent with an antiviral response during viremia. Our findings suggest that circulating sialoadhesin-expressing monocytes are capable of binding HIV-1 and effectively delivering virus to target cells thereby enhancing the distribution of HIV-1. Sialoadhesin could disseminate HIV-1 to viral reservoirs during monocyte immunosurveillance or migration to sites of inflammation and then facilitate HIV-1 infection of permissive cells.     

The role of cell death in sexually dimorphic muscle development: male-specific muscles are retained in female bax/bak knockout mice

The bulbocavernosus (BC) and levator ani (LA) muscles are present in males but absent or severely reduced in females, and the fate of these muscles controls the survival of motoneurons in the sexually dimorphic spinal nucleus of the bulbocavernosus. However, the mechanism underlying the sex difference in BC and LA development has been controversial. We examined the role of cell death in sexual differentiation of the bulbocavernosus BC/LA muscles in mice. Muscle development was mapped from embryonic day 16 (E16) to postnatal day 5 (P5). A sex difference (male>female) first arose on E17 (BC) or E18 (LA), and increased in magnitude postnatally. TUNEL labeling revealed dying cells in the BC and LA muscles of both sexes perinatally. However, females had a significantly higher density of TUNEL-positive cells than did males. A role for the proapoptotic factors, Bax and Bak, in BC/LA development was tested by examining mice lacking one or both of these proteins. In females lacking either Bax or Bak, the BC was absent and the LA rudimentary. Deletion of both bax and bak genes, however, rescued the BC, increased LA size approximately 20-fold relative to controls, and virtually eliminated TUNEL-positive cells in both muscles. We conclude that cell death plays an essential role in sexual differentiation of the BC/LA muscles. The presence of either Bax or Bak is sufficient for cell death in the BC/LA, whereas the absence of both prevents sexually dimorphic muscle cell death.