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Climate change, thermal niches, extinction risk and maternal-effect rescue of toad-headed lizards, Phrynocephalus, in thermal extremes of the Arabian Peninsula to the QinghaiTibetan Plateau
No full textDetermining the susceptibility of species to changing thermal niches is a major goal for biologists. In this paper we develop an eco-physiological model of extinction risk under climate change premised on behavioral thermoregulation. Our method downscales operative environmental temperatures, which restrict hours of activity of lizards, h(r), for present-day climate (1975) and future climate scenarios (2070). We apply our model using occurrence records of 20 Phrynocephalus lizards (or taxa in species complexes) drawn from literature and museum records. Our analysis is phylogenetically informed, because some clades may be more sensitive to rising temperatures. The limits for computed h(r) predict local extirpations among Phrynocephalus lizards at continental scales and delineate upper boundaries of thermal niches as defined by Extreme Value Distributions. Under the 8.5 Representative Concentration Pathway scenario, we predict extirpation of 64% of local populations by 2070 across 20 Phrynocephalus species, and 12 are at high risk of total extinction due to thermal limits being exceeded. In tandem with global strategies of lower CO2 emissions, we propose regional strategies for establishing new national parks to protect extinction-prone taxa by preserving high-elevation climate refugia within existing sites of species occurrence. We propose that evolved acclimatization maternal plasticity may ameliorate risk, but is poorly studied. Previous studies revealed that adaptive maternal plasticity by thermoregulating gravid females alter progeny thermal preferences by +/- 1 degrees C. We describe plasticity studies for extinction-prone species that could assess whether they might be buffered from climate warming a self-rescue. We discuss an epigenetic framework for studying such maternal-effect evolution
PI(4,5)P2 determines the threshold of mechanical force-induced B cell activation
No full textB lymphocytes use B cell receptors (BCRs) to sense the chemical and physical features of antigens. The activation of isotype-switched IgG-BCR by mechanical force exhibits a distinct sensitivity and threshold in comparison with IgM-BCR. However, molecular mechanisms governing these differences remain to be identified. In this study, we report that the low threshold of IgG-BCR activation by mechanical force is highly dependent on tethering of the cytoplasmic tail of the IgG-BCR heavy chain (IgG-tail)to the plasma membrane. Mechanistically, we show that the positively charged residues in the IgG-tail play a crucial role by highly enriching phosphatidylinositol (4,5)-biphosphate (PI(4,5)P2)into the membrane microdomains of IgG-BCRs. Indeed, manipulating the amounts of PI(4,5)P2 within IgG-BCR membrane microdomains significantly altered the threshold and sensitivity of IgG-BCR activation. Our results reveal a lipid-dependent mechanism for determining the threshold of IgG-BCR activation by mechanical force
Testing domain general learning in an Australian lizard
No full textA key question in cognition is whether animals that are proficient in a specific cognitive domain (domain specific hypothesis), such as spatial learning, are also proficient in other domains (domain general hypothesis) or whether there is a trade-off. Studies testing among these hypotheses are biased towards mammals and birds. To understand constraints on the evolution of cognition more generally, we need broader taxonomic and phylogenetic coverage. We used Australian eastern water skinks (Eulamprus quoyii) with known spatial learning ability in three additional tasks: an instrumental and two discrimination tasks. Under domain specific learning we predicted that lizards that were good at spatial learning would perform less well in the discrimination tasks. Conversely, we predicted that lizards that did not meet our criterion for spatial learning would likewise perform better in discrimination tasks. Lizards with domain general learning should perform approximately equally well (or poorly) in these tasks. Lizards classified as spatial learners performed no differently to non-spatial learners in both the instrumental and discrimination learning tasks. Nevertheless, lizards were proficient in all tasks. Our results reveal two patterns: domain general learning in spatial learners and domain specific learning in non-spatial learners. We suggest that delineating learning into domain general and domain specific may be overly simplistic and we need to instead focus on individual variation in learning ability, which ultimately, is likely to play a key role in fitness. These results, in combination with previously published work on this species, suggests that this species has behavioral flexibility because they are competent across multiple cognitive domains and are capable of reversal learning
Cryptic and cumulative impacts on the wintering habitat of the endangered black-faced spoonbill (Platalea minor) risk its long-term viability
No full textThe East Asian-Australasian flyway contains some of the most threatened habitats in the world, with at least 155 waterbird species reliant on the tidal habitats it comprises. The black-faced spoonbill (Platalea minor) is an iconic endangered species distributed across the coast of East Asia. Its population suffered a severe decline into the 1990s, but extensive monitoring and conservation interventions have aided a substantial recovery of the species. We used a population viability analysis based on data collected over the past two decades in conjunction with species distribution models to project spatially explicit models of population change for the next 35 years. Over nearly all scenarios of habitat loss and climate change, the global spoonbill population was projected to increase in the short-term due to low population numbers likely well below current population carrying capacities. However, climate change and habitat loss together threaten the recovery of the spoonbill population such that, by 2050, population declines are apparent as a consequence of these cumulative impacts. These threats are also cryptic and represent a challenge to the conservation of species recovering from anthropogenic impacts; observed population increases can hide large reductions in habitat suitability that threaten the long-term viability of species
Divergent biomass partitioning to aboveground and belowground across forests in China
No full textBelowground to aboveground biomass (BGB/AGB) ratio is a highly valued parameter of the terrestrial carbon cycle and productivity. However, it remains far from clear whether plant biomass partitioning to aboveground and belowground is isometric (equal partitioning) or allometric (unequal partitioning) at community levels and what factors are necessary in order to regulate the partitioning. This study aimed to comprehensively find out the patterns of biomass partitioning and their regulatory factors across forests in China. The data of AGB and BGB were compiled from 1542 samples for communities across forests in China. Standardized major axis regression was conducted to examine whether AGB and BGB were allocated isometrically or allometrically at a community level. Redundancy analysis was used to analyze the relationships of BGB/AGB ratio with climatic factors and soil properties. We found that the slopes of the relationship between logAGB and logBGB were not always comparable to 1.0 (isometric allocation) at community levels, including primary forest, secondary forest, and planted forest. Meanwhile, samples in clay, loam, and sand soil types also presented the same phenomenon. Furthermore, the radically different allocations of AGB and BGB were found in northern and southern China. Environmental factors totally explained 3.86% of the variations in the BGB/AGB ratio at the community level, which include the mean annual precipitation, mean annual temperature, potential water deficit index, soil carbon content, soil nitrogen content, soil clay, soil loam, soil sand, soil pH, and soil bulk density. In addition, the environmental factors also have effects on the BGB/AGB ratio in other categories. The patterns revealed in this study are helpful for better understanding biomass partitioning and spreading the carbon circle models
Neutral Loss Scan - Based Strategy for Integrated Identification of Amorfrutin Derivatives, New Peroxisome Proliferator-Activated Receptor Gamma Agonists, from Amorpha Fruticosa by UPLC-QqQ-MS/MS and UPLC-Q-TOF-MS
No full textAmorfrutins with a 2-hydroxybenzoic acid core structure are promising natural PPAR gamma agonists with potent antidiabetic activity. Owing to the complex matrix and low concentration in botanical material, the identification of unknown amorfrutins remains a challenge. In the present study, a combined application of UPLC-Q-TOF-MS and UPLC-QqQ-MS was developed to discover unknown amorfrutins from fruits of Amorpha fruticosa. First, reference compounds of amorfrutin A (AA), amorfrutin B (AB), and 2-carboxy-3,5-dihydroxy-4-geranylbibenzyl (AC) were analyzed using UPLC-Q-TOF-MS to reveal the characteristic fragment ions and the possible neutral loss. Second, the extract of A. fruticosa was separated and screened by UPLC-QqQ-MS using neutral loss scan to find out suspect compounds associated with the specified neutral fragment Delta m/z 44. Third, the extract was re-analyzed by UPLC-Q-TOF-MS to obtain the exact mass of quasi-molecular ion and fragment ions of each suspect compound, and to subsequently calculate their corresponding molecular formulas. Finally, according to the molecular formula of suspect compound and its fragment ions and comparing with literature data, structure elucidation of four unidentified amorfrutins was achieved. The results indicated that the combination of QqQ-MS neutral loss scan and Q-TOF-MS molecular formula calculation was proven to be a powerful tool for unknown natural product identification, and this strategy provides an effective solution to discover natural products or metabolites of trace content
Chemical constituents from Tsuga longibracteata and its chemotaxonomic study
No full textPhytochemical investigation into the bark of Tsuga longibracteata led to the isolation of three lignans (1-3), two triterpenoids (4, 5), nine flavonoids (6-14), three sterols (15-17) and five phenolic acids (18-22). Their structures were determined by spectroscopic analysis of their spectral data with those reported in literature. Among them, compounds 1-3, 6-22 were obtained from this species for the first time. The chemotaxonomic significance of the isolated compounds is discussed. (C) 2017 Elsevier Ltd. All rights reserved
山区农业和水资源大数据建设与智慧管理--以茂县成果为案例
No full text本专著采用3S技术等对茂县山地立体农业气候、土壤类型与质量、水资源的空间分布等进行了深入细致的分析，建立了基于GIS的山地特色农业专家支持系统，通过农业大数据对茂县农业生产要素的支撑能力与产业发展可行性进行分析，为茂县农业结构调整、绿色发展转型和实现农业可持续发展提供了具有可操作性的实施方案
Dietary fish oil replacement by soybean oil: Effect on plasma vitellogenin, sex steroids and ovarian steroidogenesis in Chinese strip-necked turtles (Mauremys sinensis)
No full textIn order to investigate the effects of dietary fish oil replacement, the turtles (Mauremys sinensis) were fed four experimental diets for 10months: FO (100% fish oil), FSO (70% fish oil and 30% soybean oil), SFO (30% fish oil and 70% soybean oil) and SO (100% soybean oil), sampled at pre-vitellogenesis, vitellogenesis and post-vitellogenesis. The results showed that plasma gonadotropin-releasing hormone (GnRH) levels were the highest at pre-vitellogenesis, which promoted the secretion of gonadotropin and sex steroids. Therefore, plasma luteinizing hormone (LH) and estrogen (E-2) levels were significantly increased at post-vitellogenesis (p<0.05), while follicle-stimulating hormone (FSH) levels increased at vitellogenesis (p<0.05). The FO and FSO groups had significantly higher GnRH and E-2 levels than the other two groups (p<0.05). In addition, plasma vitellogenin (Vtg) levels significantly increased at vitellogenesis and post-vitellogenesis (p<0.05), which were significantly higher in the groups of FO and FSO than SO (p<0.05). Moreover, the expression levels of hepatic estrogen receptor (Er) mRNA were significantly increased at vitellogenesis and post-vitellogenesis while ovarian Cyp191 mRNA were significantly increased at post-vitellogenesis (p<0.05), and both were the lowest in SO. Taken together, the replacement of fish oil with 66.7% soybean oil is feasible
Ethnopharmacology and toxicology of Pakistani medicinal plants used to treat gynecological complaints and sexually transmitted infections
No full textGynecological problems and sexually transmitted infections (STIs) are greatly affecting women health especially in developing countries due to lack of modern reproductive health facilities, poverty and different cultural norms. Consequently, a large population of Pakistan turns toward ethno-medicinal healthcare systems due to accessibility, affordability, availability and an inherent trust in this method. The present review was framed by searching different search engines for the collection of fragmented literature on indigenous knowledge of medicinal plants used by Pakistani women to treat gynecological complaints and STIs. In total, 116 plant species used in Pakistan to treat a variety of gynecological complaints and STIs. The dominant plant families used for the preparation of herbal remedies are Asteraceae and Amaranthaceae. Majority of the plants were reportedly found to be used against menses (46 plant species) followed by gonorrhea (30 plant species). The frequency of citation was also found higher for these two complications, which might be due to the higher prevalence of these problems in Pakistan. The highest number of plant species (59) was reported from Khyber Pakhtunkhwa (KPK) province of Pakistan due to more cultural resistance as compared to other provinces. Sorensen similarity index showed the highest consensus between Pashtun and Punjabi cultures of Pakistan in terms of plants and parts usage for species Convolvulus arvensis, Justicia adhatoda, Achyranthes aspera, Berberis lycium, Punica granatum and Withania somnifera. Interestingly, these plants were also reported to treat multiple reproductive problems indicating their high bioactivity. Thirteen plants including A. aspera and P. granatum have also been reportedly evaluated pharmacologically and found active confirming the efficacy of traditional medicines. Few plants (17% of total) were reportedly evaluated for toxicity, among which Nerium oleander, Euphorbia hirta and Acacia nilotica showed toxic effects on living systems. The present findings stress the need for further in-depth studies on the phytochemical, pharmacological and toxicological aspects of commonly important medicinal plants used for multiple gynecological complaints and STIs in different cultures in order to provide reliable information to the primary users and development of novel drugs. (c) 2017 SAAB. Published by Elsevier B.V. All rights reserved