Seasonal dynamics of soil fauna in the subalpine and alpine forests of west Sichuan at different altitudes

The climate (especially temperature) often plays an important role in the structure, function as well as composition of soil organisms in different latitudes and altitudes. As one of the essential components of soil ecosystem, soil faunal community not only lays their roles as soil engineer in material cycling and energy flow, but also acts as the sensitive bio-indicator to environmental change. However, little information has been available on the responses of soil faunal community to the changed environment at different altitudes and seasons. In order to understand the seasonal dynamics of soil faunal diversity under different forests with varying altitudes, three fir (Abies faxoniana) forests were selected covering a 600 m vertical transition zone. The primary fir forest at 3600 m (A1) of altitude, mixed fir and birch forest at 3300 m (A2) of altitude, and secondary fir forest at 3000 m (A3) of altitude are representative forests in the subalpine and alpine region of west Sichuan. A 2 years study was conducted in the three subalpine and alpine forests from May in 2009 until October in 2010. Soil samples were collected in both the soil organic layer and mineral soil layer. Soil macro-fauna were picked up by hand in the fields. Meso/micro-fauna and damp living fauna were separated and collected from the soil samples by Baermann and Tullgren methods in laboratory, respectively. A total of 74,827 individuals were collected in the 2 years, belonging to seven phyla, 16 classes, 31 orders and 125 families by preliminary identification. Similar dominant groups were detected in different forests at different altitudes, consisting of Spirostreptida, Formicidae, Staphylinidae, Hesperinidae, Onychiuridae, Isotomidae, Oribatuloidae, Alicoragiidae, Secernentea, and Adenophorea. In contrast, the ordinary species of macro-fauna and the ratios of Acarina to Collembolan were obviously different. For instance, the ordinary species were dominated by Cydmaenidae and Mycetophilidae at the A1, Scaphidiidae and Helicinidae at the A2, and Lumbricida and Agelenidae at the A3, respectively. Both the individual density and the number of soil faunal groups were significantly higher in soil organic layer than those in mineral soil layer. The density and group of macro-, meso- and micro-fauna in different forests showed the order as A2 > A1 > A3, but the density of damp living fauna showed the order as A1 > A2 > A3. The functional groups of macro-fauna were mainly dominated by saprozoic. The highest density and group of macro-fauna was observed in August, while the highest value of meso/micro-fauna was detected in October. In addition, the Jacard similarity indices showed that the composition and structure of soil fauna were similar in the different forests varied with altitudes, but the Shannon–Wiener indices were significantly different. The highest values of Shannon–Wiener indices were observed in October at both the A1 and A3, and in August at the A2. The results suggested that soil faunal community kept a high diversity in the subalpine and alpine forests of west Sichuan, and their structures were significantly affected by the variation of altitudes, which provided important scientific evidences for understanding the ecological processes in the subalpine and alpine coniferous forests.     

Studies on the effect of reagent and protein charges on reactivity of the β93 sulfhydryl group of human hemoglobin using selected mutations

The reactivity of the β93 sulfhydryl (SH) group of human oxyhemoglobins with the negatively charged 5,5′-dithiobis(2,2′-nitrobenzoate) and the uncharged 2,2′-dithiodipyridine was determined as a function of pH. Selected mutant hemoglobins having increased oxygen affinity and having residue substitutions altering charge near the SH group (Wood, Malmö, Yakima, Kempsey, Andrew-Minneapolis, Osler, and Chesapeake) were compared to hemoglobin (Hb) A. Although both reagents reacted with GSH at the same rate and with the same enthalpies of activation, the rates with Hb were different and the difference showed a pronounced pH dependence. The charged reagent was sensitive to charges near the SH group; a positive charge increased the rate and a negative one decreased the rate. The uncharged reagent which reacted with Hb A with activation enthalpies similar to those for GSH was insensitive to neighboring charges, but was sensitive to tertiary and quaternary structural changes. The rates obtained with the latter reagent did not correlate with oxygen affinity. The evolutionary aspects of the β93 cysteine in relation to structure and function are reviewed.     

Lipocalin-2: pro- or anti-apoptotic?

Survival and apoptosis signaling pathways are altered concomitantly in response to numerous endogenous and exogenous stressors. The lipocalin family of small soluble proteins has been implicated in modulating apoptosis. However, the overall effect of these proteins has been variable, showing both pro- and anti-apoptotic activities. The goal of this minireview is to summarize the studies on lipocalins and apoptosis and consider what roles lipocalin-2 may play in cell death and survival.     

Using sensitivity analysis to identify keystone species and keystone links in size‐based food webs

Human‐induced alterations in the birth and mortality rates of species and in the strength of interactions within and between species can lead to changes in the structure and resilience of ecological communities. Recent research points to the importance of considering the distribution of body sizes of species when exploring the response of communities to such perturbations. Here, we present a new size‐based approach for assessing the sensitivity and elasticity of community structure (species equilibrium abundances) and resilience (rate of return to equilibrium) to changes in the intrinsic growth rate of species and in the strengths of species interactions. We apply this approach on two natural systems, the pelagic communities of the Baltic Sea and Lake Vättern, to illustrate how it can be used to identify potential keystone species and keystone links. We find that the keystone status of a species is closely linked to its body size. The analysis also suggests that communities are structurally and dynamically more sensitive to changes in the effects of prey on their consumers than in the effects of consumers on their prey. Moreover, we discuss how community sensitivity analysis can be used to study and compare the fragility of communities with different body size distributions by measuring the mean sensitivity or elasticity over all species or all interaction links in a community. We believe that the community sensitivity analysis developed here holds some promise for identifying species and links that are critical for the structural and dynamic robustness of ecological communities.     

沉没湖底的"华北之花"

提起新中国的第一个机械化农场——冀衡农场，也许很少有人知道。这个农场就淹没在衡水湖底……[编者按]     

Mediators of ocular angiogenesis

Angiogenesis is the formation of new blood vessels from pre-existing vasculature. Pathologic angiogenesis in the eye can lead to severe visual impairment. In our review, we discuss the roles of both pro-angiogenic and anti-angiogenic molecular players in corneal angiogenesis, proliferative diabetic retinopathy, exudative macular degeneration and retinopathy of prematurity, highlighting novel targets that have emerged over the past decade.     

Effects of rosuvastatin on electronegative LDL as characterized by capillary isotachophoresis: the ROSARY Study

Electronegative LDL, a charge-modified LDL (cm-LDL) subfraction that is more negatively charged than normal LDL, has been shown to be inflammatory. We previously showed that pravastatin and simvastatin reduced the electronegative LDL subfraction, fast-migrating LDL (fLDL), as analyzed by capillary isotachophoresis (cITP). The present study examined the effects of rosuvastatin on the more electronegative LDL subfraction, very-fast-migrating LDL (vfLDL), and small, dense charge-modified LDL (sd-cm-LDL) subfractions. Patients with hypercholesterolemia or those who were being treated with statins (n = 81) were treated with or switched to 2.5 mg/d rosuvastatin for 3 months. Rosuvastatin treatment effectively reduced cITP cm-LDL subfractions of LDL (vfLDL and fLDL) or sdLDL (sd-vfLDL and sd-fLDL), which were closely related to each other but were different from the normal subfraction of LDL [slow-migrating LDL (sLDL)] or sdLDL (sd-sLDL) in their relation to the levels of remnant-like particle cholesterol (RLP-C), apolipoprotein (apo) C-II, and apoE. The percent changes in cm-LDL or sd-cm-LDL caused by rosuvastatin were correlated with those in the particle concentrations of LDL or sdLDL measured as LDL-apoB or sdLDL-apoB and the levels of HDL-C, RLP-C, apoC-II, and apoE. In conclusion, rosuvastatin effectively reduced both the vfLDL subfraction and sd-cm-LDL subfractions as analyzed by cITP.     

Facial Skin Coloration Affects Perceived Health of Human Faces

Numerous researchers have examined the effects of skin condition, including texture and color, on the perception of health, age, and attractiveness in human faces. They have focused on facial color distribution, homogeneity of pigmentation, or skin quality. We here investigate the role of overall skin color in determining perceptions of health from faces by allowing participants to manipulate the skin portions of color-calibrated Caucasian face photographs along CIELab color axes. To enhance healthy appearance, participants increased skin redness (a*), providing additional support for previous findings that skin blood color enhances the healthy appearance of faces. Participants also increased skin yellowness (b*) and lightness (L*), suggesting a role for high carotenoid and low melanin coloration in the healthy appearance of faces. The color preferences described here resemble the red and yellow color cues to health displayed by many species of nonhuman animals.