Can mobile sandy land be vegetated in the cold and dry Tibetan Plateau in China?

Desertification has taken place in the overgrazed grassland of the Tibetan Plateau, China, and the area of mobile sandy land has increased in recent decades. The challenging problem about desertification control is how to restore the vegetation of mobile sandy lands caused by severe desertification. Sand drifting is now regarded as the limiting factor of vegetation restoration in such lands. The initial phase of vegetation restoration is plant colonization, but it is often aborted due to sand drifting, and then vegetation restoration fails to proceed. For the sake of revegetation, the first step is to stop sand drifting to ensure plant colonization. In the northeastern Tibetan Plateau, China, feasible approaches have been found through long-term experiments, and the vegetation is being restored satisfactorily with these approaches in experimental sandy lands. The approaches comprise three types: enclosure, mechanical barriers and biological barriers. Different sandy lands require dissimilar combinations of these approaches. Enclosures may be adequate to revegetate inter-dunes or degraded grassland even in cold regions like the Tibetan Plateau, China, but it is deficient for revegetation of the shifting sand dunes unless mechanical and biological barriers are established simultaneously.     

Rumen methanogen and protozoal communities of Tibetan sheep and Gansu Alpine Finewool sheep grazing on the Qinghai–Tibetan Plateau,China

Background

Tibetan sheep (TS) and Gansu Alpine Finewool sheep (GS) are both important plateau sheep raised and fed on the harsh Qinghai–Tibetan Plateau, China. Rumen methanogen and protozoal communities of plateau sheep are affected by their hosts and living environments, and play important roles in ruminant nutrition and greenhouse gas production. However, the characteristics, differences, and associations of these communities remain largely uncharacterized.

Results

The rumen methanogen and protozoal communities of plateau sheep were investigated by 16S/18S rRNA gene clone libraries. The predominant methanogen order in both sheep species was Methanobacteriales followed by Methanomassiliicoccales, which is consistent with those seen in global ruminants. However, the most dominant species was Methanobrevibacter millerae rather than Methanobrevibacter gottschalkii seen in most ruminants. Compared with GS and other ruminants, TS have more exclusive operational taxonomic units and a lower proportion (64.5%) of Methanobrevibacter. The protozoa were divided into Entodiniomorphida and Vestibuliferida, including nine genera and 15 species. The proportion of holotrich protozoa was much lower (1.1%) in TS than ordinary sheep. The most predominant genus was Entodinium (70.0%) in TS and Enoploplastron (48.8%) in GS, while the most common species was Entodinium furca monolobum (43.9%) and Enoploplastron triloricatum (45.0%) in TS and GS, respectively; Entodinium longinucleatum (22.8%) was only observed in TS. LIBSHUFF analysis indicated that the methanogen communities of TS were significantly different from those of GS, but no significant differences were found in protozoal communities.

Conclusion

Plateau sheep have coevolved with unique rumen methanogen and protozoal communities to adapt to harsh plateau environments. Moreover, the host appears to have a greater influence on rumen methanogen communities than on rumen protozoal communities. The observed associations of methanogens and protozoa, together with the findings of previous studies on methane emissions from ruminant livestock, revealed that the lower proportion of Methanobrevibacter and holotrich protozoa may be responsible for the lower methane emission of TS. These findings facilitate our understanding of the rumen microbial ecosystem in plateau sheep, and could help the development of new strategies to manipulate rumen microbes to improve productivity and reduce the emission of greenhouse gases.

     

Can intact liposomes be absorbed in the gut?

Inulin, EDTA, or maltose were given intragastrically to mice, either free or entrapped in mono-shell liposomes of egg phosphatidylcholine or the non-digestible diether and dialkyl analog of phosphatidylcholine. Results indicate that liposomes may protect a drug from premature digestion but cannot carry it through the intestinal wall.     

Gammaproteobacterial Diversity and Carbon Utilization in Response to Salinity in the Lakes on the Qinghai–Tibetan Plateau

The Gammaproteobacteria are widely and abundantly distributed in various environments, and they play important roles in the geochemical cycles of biogenic elements (e.g., C, N and S) in the ecosystems. Previous studies showed that Gammaproteobacteria dominate in saline and hypersaline lakes. However, little is known on how salinity influences gammaproteobacterial community composition and their ecological functions (i.e., organic carbon degradation). In this study, we investigated the gammaproteobacterial diversity and carbon utilization and their response to salinity in six saline/hypersaline lakes and one freshwater lake on the Qinghai–Tibetan Plateau (QTP). The results indicated that the gammaproteobacterial community composition was mainly influenced by the salinity of the studied QTP lakes. Salinity was also a key environmental factor influencing the carbon utilization ability of Gammaproteobacteria: within one genus (e.g., Halomonas, Pseudoalteromonas, Vibrio) the strains retrieved from low-salinity environments had stronger carbon utilization ability than their counterparts from high-salinity environments; within one genus, the strains isolated from lakes with different salinity shared similar carbon utilization preference, indicating that species belonging to the same genus may execute similar ecological functions in the environments regardless of salinity.     

Impact of land use on plant biodiversity and measures for biodiversity conservation in the Loess Plateau in China – a case study in a hilly-gully region of the Northern Loess Plateau

The Loess Plateau is a special natural–cultural unit in northern China. Intensive land use in the past has had, and forestation and grass planting at present will have inevitable impacts on plant biodiversity in the Loess Plateau. Based on the analysis of floristic features within three sampling sites with different land use practices and analysis of species richness among different land use types, we discuss impacts of land use on species richness and floristic features in the Northern Loess Plateau. The results drawn from this case study are as follows: (1) It appears that forestation and grass planting have had a positive influence on the local species diversity, but they have contributed little to the native vegetation in terms of conserving its floristic features. (2) Caragana intermedia shrubland, Pinus tabulaeformis forestland, and natural grassland have made important contributions to supporting indigenous species and maintaining local plant biodiversity. (3) There is a significant positive correlation between land use diversity and species richness. These results imply that practicing biodiversity conservation in situ is feasible and the suitable choice for the Loess Plateau. Concrete measures for biodiversity conservation in the area can include setting up small nature reserves and diversifying land use patterns to maintain as much habitat as possible for native vegetation. The artificial Hippophae rhamnoides shrubland should not be further promoted, considering its negative influence on biodiversity conservation.     

Changes in water use with growth in Ulmus pumila in semiarid sandy land of northern China

Key message

Ulmus pumila vary its water use strategy from seedling to maturity in a water-limited sandy land by adopting different photosynthetical capacities, water use efficiencies and morphological traits.

Abstract

Regeneration failure of natural Ulmus pumila populations has become a growing concern related to vegetation conservation and prediction of environmental change in the sandy lands of northern China. To better understand the life-history strategies of U. pumila and its adaptation to drought in semiarid environments, we studied ecophysiological and morphological traits related to water use in an age sequence of U. pumila representing four age classes: current-year seedlings (Uc), age 2- to 5-year-old saplings (Us), juveniles (Uj), and mature trees (Um). A comparison of hydrogen isotope data in xylem sap, soil water in different layers and groundwater showed that Uc relied on the soil water in the topsoil (0–40 cm), Us and Uj absorbed soil water from deeper soil (>40 cm), while Um mainly used stable groundwater with very deep (>2 m) taproots. Significantly lower predawn leaf water potentials were observed in Uc than in Uj or Um, suggesting that Uc experienced more severe water stress and had a weaker capacity to recovery. Moreover, Uc had the highest daily maximum net assimilation rate, daily maximum transpiration rate and daily maximum stomatal conductance, all of which decreased remarkably at midday. A “go for broke” strategy is probably practiced by Uc which try to provide the growth they need to become established, but with a great risk of mortality. Um used a more conservative strategy by effectively regulating the instantaneous water-use efficiency, and maintaining both stable gas exchange levels and significantly higher long-term water-use efficiency. Uj endured and adapted to drought conditions by developing steeper leaf angles, denser leaf pubescence and more stomata than differently aged plants. Our findings illustrate that significantly different water-use strategies were developed by U. pumila trees as they grew from seedlings to maturity, which were based on different water sources.     

Can changes in the distributions of resident birds in China over the past 50?years be attributed to climate change?

The distributions of bird species have changed over the past 50 years in China. To evaluate whether the changes can be attributed to the changing climate, we analyzed the distributions of 20 subspecies of resident birds in relation to climate change. Long‐term records of bird distributions, gray relational analysis, fuzzy‐set classification techniques, and attribution methods were used. Among the 20 subspecies of resident birds, the northern limits of over half of the subspecies have shifted northward since the 1960s, and most changes have been related to the thermal index. Driven by climate change over the past 50 years, the suitable range and latitude or longitude of the distribution centers of certain birds have exhibited increased fluctuations. The northern boundaries of over half of the subspecies have shifted northward compared with those in the 1960s. The consistency between the observed and predicted changes in the range limits was quite high for some subspecies. The changes in the northern boundaries or the latitudes of the centers of distribution of nearly half of the subspecies can be attributed to climate change. The results suggest that climate change has affected the distributions of particular birds. The method used to attribute changes in bird distributions to climate change may also be effective for other animals.     

Can Saturniidae moths be bioindicators? Spatial and temporal distribution in the Brazilian savannah

Some moths species are considered good indicators of habitat quality because they are very responsive to human disturbance, vegetation type, and successional processes. However, Saturniidae moths have not yet been considered as indicators of environmental quality. Little is known on the distribution of moth species in different vegetation types and the moths’ seasonal variations in the Brazilian savannah. Therefore, this study aims to describe the spatial distribution and temporal patterns of moths belonging to the Saturniidae family in two vegetation types—Cerrado sensu stricto on rocky outcrops and semi-deciduous forest—in both the rainy and dry seasons. It addresses the influence of the climatic seasons and vegetation types on abundance, richness, and species composition to describe the temporal and spatial distribution patterns and the relationship between the ecological aspects and the life history of these moths. This study was conducted in the Cerrado phytogeographical domain, in Pireneus State Park, Goiás, Brazil. The results revealed that most Saturniidae species sampled are present during the rainy season and typically found in forest habitats. Furthermore, a clear positive connection was found between the abundance pattern and rainfall seasonality and humid habitats; this is apparently related to the physiological tolerance of these moths, due to rudimentary mouthparts during their adulthood. Thus, rainfall and a forest habitat are important to and fundamental requirements for the persistence of the Saturniidae species in the Cerrado domain. Based on the results of this study, we suggest the use of saturniid species as indicators of changes in vegetation and climatic conditions.     

Is cold hardiness size-constrained? A comparative approach in land snails

Body water is a major element of the cold-hardiness strategies observed in ectothermic animals, in particular in freezing avoidant species for which body ice formation is lethal. Here, we investigate the relationships, in terrestrial snails, between the temperature of crystallisation (Tc) and body water (water mass and water content), shell shape, geographic and climatic distribution, taking into account phylogenetic inertia. Phylogenetic relationships among 31 species from 13 different families of terrestrial Gastropods were studied using 28S rRNA nuclear and COI mitochondrial sequence data, together with species-specific traits. Our results provide evidence for clear relationships between Tc and absolute/relative body water: smaller species with lower water content tended to be characterized by colder temperatures of crystallisation, although some exceptions were noticeable. Environmental conditions do not appear to affect Tc significantly, as well as shell shape which is however correlated with water content. This study confirmed that supercooling ability in land snails is size-constrained, with consequences on cold-hardiness strategies.     

Can the aging influence cold environment mediated cancer risk in the USA female population?

Cancer is one of the most debilitating diseases worldwide. Cancer incidence and/or death depends on several intrinsic and extrinsic factors (e.g., dietary habits, socio-behavioral activities, physical inactivity, smoking, alcohol consumption, gender, races/ethnicities and age). Various studies have found that an inverse relationship subsists between environmental temperature and cancer risk. Furthermore, this negative relationship was found to be more consistent in the USA female population. This research mainly focuses on influence of aging on cold environment mediated cancer risk for overall and various anatomical site-specific cancers. Age-specific county-wise data of cancer incidence rate (CIR) in the USA female population was selected in this study. Statistical analysis found a negative correlation between the average annual temperature (AAT) and CIR in all anatomical sites (AAS; overall) as well as different anatomical site-specific cancers (e.g., breast, melanoma, leukaemia, pancreas, bladder, uterus, thyroid and non-Hodgkin's lymphoma (NHL), except for cervical cancer) in different age groups (e.g., less than 50 years, 50 plus years, less than 65 years and 65 plus years). In addition, an inverse relationship between the AAT and CIR was found in case of paediatric cancer. However, all the results obtained from the linear model based statistical analysis proposed that the older age-group of females particularly above 65 years seems to be more prone to cold temperature linked cancer risk. For example, age-specific cold linked cancer incidence appears to be more inclined in case of breast cancer in the age-group of 65 plus years. This study, for first time, proposes that aging may have a positive influence on the relationship between cancer incidence and environment temperature.     

Can the Lilliput Effect be detected in the brachiopod faunas of South China following the terminal Ordovician mass extinction?

In the immediate aftermath of global extinctions, organisms were normally much smaller than those prior to these events. This ‘Lilliput Effect’ can be subdivided into two types: 1) a specific type, following the original definition of the effect which targets species-level taxa associated with inhospitable environments, and 2) a more general type, related to the reactions of higher-rank taxa above the species-level. The body sizes of brachiopods from South China through the Ordovician and Silurian transition (Late Katian, Hirnantian, and earliest Rhuddanian) are compared at generic, superfamilial, ordinal, and class levels. The results indicate that the body sizes of the taxa of lower rank (e.g. genus-level) are highly variable within these different intervals. The type of evidence for the Lilliput Effect through the end Ordovician mass extinction is thus quite different from that of the end Permian mass extinction probably reflecting differences in the intensity of these two major bioevents. However, the relationships between the contrasting trends in body-size change of some taxa of higher rank (e.g. at the ordinal-level) and the relative dominance of these taxa in the latest Ordovician and earliest Silurian suggest that the brachiopods of the two major Ordovician groups, the strophomenoids and orthoids, adopted different survival strategies during and immediately after the crisis from those of the pentamerides and rhynchonellides, that were common in Silurian assemblages.     

Can the false-discovery rate be misleading?

The decoy-database approach is currently the gold standard for assessing the confidence of identifications in shotgun proteomic experiments. Here, we demonstrate that what might appear to be a good result under the decoy-database approach for a given false-discovery rate could be, in fact, the product of overfitting. This problem has been overlooked until now and could lead to obtaining boosted identification numbers whose reliability does not correspond to the expected false-discovery rate. To overcome this, we are introducing a modified version of the method, termed a semi-labeled decoy approach, which enables the statistical determination of an overfitted result.     

Can the Endo Medium be Standardized?

An investigation of various formulae for the Endo medium has been made, using about 20 different samples of basic fuchsia. It has been found that some samples are unsatisfactory in the standard formula of the American Public Health Association and others unsatisfactory in the formula given in the Manual of Methods for Pure Culture Study of Bacteria (of the Society of American Bacteriologists). A slight modification of the A. P. H. A. standard formula, however, is enough to make it satisfactory for any sample of basic fuchsin with which it has so far been tried. This modification is the use of 1 ml. of a 1% basic fuchsin solution instead of 0.5 ml. of a 10% solution. This modification in the formula brings about a change of the ratio of sulfite to fuchsin in the finished medium of 12 1/2:1 instead of roughly 3:1; and it is shown that this ratio permits the use of a greater variety of different fuchsins than the one which is in the standard formula.     

Diversity and dispersal — Can the link be approached experimentally?

It has been hypothesized that the relative role of species dispersal in determining plant community composition and species richness changes along primary productivity and disturbance intensity gradients. Manipulative experiments with either diaspore addition or prevention are needed to validate this hypothesis. Due to methodological constraints, diaspore prevention experiments are rarely used. In the case of diaspore addition experiments, there are some potential sources of error. (1) Experiments may be confounded since patchiness of microbial communities is not considered and techniques equalizing microbial communities over study plots are not used. (2) The length of the period of observation may not be sufficient to understand whether the establishment of sown individuals was really successful. (3) The effect of the sowing treatment and the theoretical context of the whole experiment depends on the number and identity of species sown. When addressing the role of long-distance dispersal, it is almost impossible to say what the appropriate number and composition of species to be used for the experiment should be. (4) Until now, most of the attention has been on dispersal in space, while the role of “dispersal in time” (seed bank) has rarely been addressed. We conclude that stepwise accumulation of experimental studies, addressing the role of dispersal in shaping plant communities, will sooner or later reveal general patterns, given the experiments are well planned and aim to avoid the sources of errors described above.     

Can antioxidants be beneficial in the treatment of lead poisoning?

Recent studies have shown that lead causes oxidative stress by inducing the generation of reactive oxygen species, reducing the antioxidant defense system of cells via depleting glutathione, inhibiting sulfhydryl-dependent enzymes, interfering with some essential metals needed for antioxidant enzyme activities, and/or increasing susceptibility of cells to oxidative attack by altering the membrane integrity and fatty acid composition. Consequently, it is plausible that impaired oxidant/antioxidant balance can be partially responsible for the toxic effects of lead. Where enhanced oxidative stress contributes to lead-induced toxicity, restoration of a cell's antioxidant capacity appears to provide a partial remedy. Several studies are underway to determine the effect of antioxidant supplementation following lead exposure. Data suggest that antioxidants may play an important role in abating some hazards of lead. To explain the importance of using antioxidants in treating lead poisoning the following topics are addressed: (i) Oxidative damage caused by lead poisoning; (ii) conventional treatment of lead poisoning and its side effects; and (iii) possible protective effects of antioxidants in lead toxicity.     

Can Shaker Potassium Channels be Locked in the Deactivated State?

For structural studies it would be useful to constrain the voltage sensor of a voltage-gated channel in its deactivated state. Here we consider one Shaker potassium channel mutant and speculate about others that might allow the channel to remain deactivated at zero membrane potential. Ionic and gating currents of F370C Shaker, expressed in Xenopus oocytes, were recorded in patches with internal application of the methanethiosulfonate reagent MTSET. It appears that the voltage dependence of voltage sensor movement is strongly shifted by reaction with internal MTSET, such that the voltage sensors appear to remain deactivated even at positive potentials. A disadvantage of this construct is that the rate of modification of voltage sensors by MTSET is quite low, approximately 0.17 mM(-1).s(-1) at -80 mV, and is expected to be much lower at depolarized potentials.     

Can Coral Cover be Restored in the Absence of Natural Recruitment and Reef Recovery?

With many coral reef areas being degraded whether by anthropogenic or natural causes, a search is on for resilient species of corals that can restore coral cover where needed, if coral reefs are to continue to provide adequate ecosystem services. A series of experiments were undertaken in two sites with different environmental attributes and substrates in a lagoonal area in the northwestern Philippines to test the potentials of a local species, Porites cylindrica, for reef rehabilitation. With the use of asexual fragmentation of donor colonies, different treatments were tested, particularly to determine if the species would survive on different substrates, that is, solid, massive versus digitate/anastomosing, dead colonies. The results after nearly 2 years of the experiment were extraordinarily successful, with survival of transplants ranging from a high of 98% to a low of 80% of colonies, resulting in extensive coral cover on both original and new or different substrate from the original. A subsequent observation after another 16 months showed the coral cover to have been complete or nearly complete in the experimental plots, with the transplanted colonies fusing, and with evident reef fish communities where there were none before. Had there been no intervention, it is highly likely that the reefs would have remained in a degraded state .     

Is precipitation a trigger for the onset of xylogenesis in Juniperus przewalskii on the north-eastern Tibetan Plateau?

Background and Aims A series of studies have shown that temperature triggers the onset of xylogenesis of trees after winter dormancy. However, little is known about whether and how moisture availability influences xylogenesis in spring in drought-prone areas.Methods Xylogenesis was monitored in five mature Qilian junipers (Juniperus przewalskii) by microcore sampling from 2009 to 2011 in a semi-arid area of the north-eastern Tibetan Plateau. A simple physical model of xylem cell production was developed and its sensitivity was analysed. The relationship between climate and growth was then evaluated, using weekly wood production data and climatic data from the study site.Key Results Delayed onset of xylogenesis in 2010 corresponded to a negative standardized precipitation evapotranspiration index (SPEI) value and a continuous period without rainfall in early May. The main period of wood formation was in June and July, and drier conditions from May to July led to a smaller number of xylem cells. Dry conditions in July could cause early cessation of xylem differentiation. The final number of xylem cells was mainly determined by the average production rate rather than the duration of new cell production. Xylem growth showed a positive and significant response to precipitation, but not to temperature.Conclusions Precipitation in late spring and summer can play a critical role in the onset of xylogenesis and xylem cell production. The delay in the initiation of xylogenesis under extremely dry conditions seems to be a stress-avoidance strategy against hydraulic failure. These findings could thus demonstrate an evolutionary adaptation of Qilian juniper to the extremely dry conditions of the north-eastern Tibetan Plateau.