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Microhabitat Segregation of Parapatric Frogs in the Qinling Mountains
Full text linkCoexistence mechanisms for species with similar ecological traits and overlapping geographic distributions are basic questions in ecology and evolutionary biology. Specific habitat requirements often limit distribution range as well as facilitate partitioning resource utilization in ecological similar species. Understanding niche segregation and differences in microhabitat utilization can contribute to identifying coexistence mechanisms between parapatric species. Feirana quadranus and F. taihangnica are two closely related frog species with parapatric geographic ranges and an elongated contact zone within the Qinling Mountains, which is an important watershed for East Asia. Here, we analysed the difference in microhabitat utilization between the two frog species and explored the key ecological factors that induced their microhabitat differentiation based on quadrats sampled in the contact zone. Our comparison of twenty environmental variables showed that both species used microhabitats with alkalescent warm water and gentle slope conditions. The principal component analysis indicated that climate-related variables, vegetation conditions, and river width were the important factors for microhabitat utilization of these species. These findings contribute to our understanding on the coexistence mechanisms of these two related and parapatric Asian mountain frog species. This study can also be helpful for identifying target habitats to conduct conservation actions and management strategies effectively in the face of environmental changes
Embryonic Growth and Yolk Depletion during Incubation in the Chinese Skink, Plestiodon chinensis
Full text linkWe collected 24 gravid female Chinese skinks (Plestiodon chinensis) to study embryonic growth and yolk depletion during incubation. Females laid eggs between late May and mid-June. Eggs were incubated at 24 (± 0.3) °C. One egg from each clutch was dissected at 5-d intervals starting at laying. Embryonic stages at laying varied from Dufaure and Hubert’s (1961) Stage 30−35, with a mean stage of 32.6. Incubation lengths at 24 °C varied from 35.1 to 48.3 d, with a mean of 41.5 d. Based on the derived functions describing instantaneous changes in embryo dry mass and yolk dry mass, we identified three phases of embryonic growth or yolk depletion in P. chinensis. Phase 1, from Day 0 (at laying) to Day 15 (~36% of the way through incubation), was one of minimal transfer of material from yolk to embryo. Phase 2, from Day 15 to Day 32−33 (~77%−80% of the way through incubation), was characterized by increasingly rapid embryonic growth or yolk depletion. Phase 3, from Day 32−33 to hatching, was characterized by reduced embryonic growth or yolk depletion. The length of the last embryonic stage (Stage 40 = completely differentiated embryos) accounted for about 28% of incubation length, and the dry mass of the smallest embryos of Stage 40 accounted for only ~48% of the hatchling dry mass. Our study adds evidence to the idea that oviposition is not timed to coincide with the onset of rapid embryonic growth in oviparous reptiles, and is first to demonstrate that ~50% embryonic growth occurs in the last quarter of incubation in P. chinensis
Agronomic and Quality Traits of Different Dendrobium nobile Lines in Hejiang
No full text目的:对合江金钗石斛3个品系(JC-1,JC-2,JC-3)主要农艺性状与品质进行比较,为合江金钗石斛生产提供指导,为金钗石斛新品种选育提供参考依据。方法:用直尺、游标卡尺和分析天平等测定了合江金钗石斛的主要农艺性状与产量性状;采用苯酚-硫酸比色法和酸性染料比色法分别测定茎中多糖与总生物碱含量。结果:2年生的JC-1在茎节数、节间长、茎鲜重与茎干重方面表现最佳。从茎长来看,无论是1年生,2年生还是3年生,均表现为JC-1>JC-2>JC-3。茎粗则随着年限的增长而增粗,JC-2粗于JC-1和JC-3,且JC-2从2年生到3年生这个阶段增长迅速。折干率均表现为2年生大于1年生与3年生,JC-1的折干率远大于JC-2与JC-3。JC-3株型最小,折干率最低。在有效成分含量方面,多糖质量分数为JC-1(4.64%)>JC-2(3.02%)>JC-3(2.20%);总生物碱质量分数为JC-3(0.59%)>JC-2(0.48%)>JC-1(0.45%),但折算为茎鲜品中多糖与总生物碱含量均为JC-1最高。结论:综合生产及品质等角度,笔者认为合江金钗石斛品系JC-1最适合推广种植
A Multi-Class, Multi-Residue Method for Detection of Veterinary Drugs in Multiple Meat Using a Pass-Through Cleanup SPE Technique and UPLC-MS/MS Analysis
No full textA quantitative method using ultra-performance liquid chromatography coupled with tandem mass spectrometry (UPLC-MS/MS) was developed for the determination of 60 compounds, belonging to a variety of veterinary drug (VD) classes, in meat. The included analytes belong to the following VD classes: beta-agonists, sulfanilamides, quinolones, macrolides, tetracyclines, beta-lactams, nitroimidazoles, glucocorticoids, sex hormones, chloromycetins, sedatives, and olaquindox metabolite. The effective PRiME pass-through cleanup procedure was used to ensure high extraction efficiency and good sample cleanup after a simple liquid extraction of the meat samples with acetonitrile/water. The developed method was validated successfully. Mean recoveries for all analytes ranged from 80 to 116%, with the relative standard deviations (RSDs) <= 7.8%. Limits of quantification were in the range 0.05-3.0 mu g kg(-1) and limits of detection were in the range 0.1-10 mu g kg(-1). The matrix effect was evaluated for the different meat matrices and was found to be markedly different in different matrices. The validated method was used in a pilot study to analyze real samples of pork, beef, mutton, chicken, and pork liver, lambs' liver, and chicken liver. Trace amounts of beta-agonists, oxytetracycline, quinolones, chloromycetin sulfadimidine, and 3-methyl-quinoxaline-2-carboxylicacid were detected in these samples. In conclusion, this workflow can provide a simpler and more cost-effective alternative to conventional analytical methods and is compatible with processing large sample numbers in a short time period
Rapid quantification of aloin A and B in aloe plants and aloe-containing beverages, and pharmaceutical preparations by microchip capillary electrophoresis with laser induced fluorescence detection
No full textA microchip capillary electrophoresis coupled with laser induced fluorescence detection method for the fast determination of aloin was developed and comprehensively applied for the quantification of aloinA and B present in seven aloe plant species, 42 aloin-containing crude drugs, ten aloe pharmaceutical preparations, and four aloe gel-containing functional foods. The excitation and emission wavelengths for detection of both aloins were set at 473 and 520nm, respectively. Sample analysis on a 35mm length of glass microchip channel was completed within 40 s. An interference study indicated that the other main anthraquinones present in the samples did not interrupt with the target aloins detection, demonstrating the good selectivity of this method. It is demonstrated that this method is fast, facile, and specific for determination of aloinA and B from matrix samples which can be applied to the quality control of a wide varieties of aloe species and aloe-derived products
Characterization and coagulation-flocculation performance of a composite flocculant in high-turbidity drinking water treatment
No full textKlebsiella variicola B16, a microbial bioflocculant (MBF-B16)-producing bacteria, was isolated and identified by its 16S rRNA sequence, biochemical properties, and physiological characteristics. The effects of culture conditions on MBF-B16 production, including carbon source, nitrogen source, C/N ratio, initial pH, and culture temperature, were investigated in this study. Results showed that 6.96 g of MBF-B16 could be extracted from a 1-L culture broth under optimized conditions. Chemical analysis showed that polysaccharide and protein were the main components. The neutral sugar consisted of galactose only, which was proposed in Klebsiella genus for the first time. In addition, a composite flocculant (CF) that contains polyaluminum ferric chloride (PAFC) and MBF-B16 for the removal of turbidity and SS in drinking water was optimized by response surface methodology. CF could reduce PAFC dosage by about 56.2-72%. Charge neutralization and adsorption bridging effect were the primary flocculation mechanisms. (C) 2018 Elsevier Ltd. All rights reserved
Comparison of Root Surface Enzyme Activity of Ericaceous Plants and Picea abies Growing at the Tree Line in the Austrian Alps
No full textPlants with ericoid mycorrhizal and ectomycorrhizal associations coexist at the tree line and in many boreal forests. Both ericoid mycorrhizal and ectomycorrhizal roots are known to produce extracellular enzymes, but ericoid mycorrhizal fungi have been demonstrated in vitro to have higher enzyme activities. On hair roots of four ericoid mycorrhizal species (Rhododendron ferrugineum, Vaccinium vitis-idaea, Vaccinium myrtillus, Calluna vulgaris) and on ectomycorrhizal and non-mycorrhizal root tips of Picea abies growing at the tree line (1700 m) in the Austrian Alps, potential activities of eight extracellular root enzymes were estimated. Our results show that the activities of all the different extracellular root enzymes were generally similar among the ericaceous plant species. The mean laccase enzyme activity of ectomycorrhizal root tips of Picea abies was significantly higher than that of both the hair roots and fine roots of the ericaceous species. Leucine-amino-peptidase activity on hair roots was significantly higher than on non-mycorrhizal fine roots for the ericaceous vegetation. However, the mean activity of -glucuronidase of the ericaceous species was significantly higher in fine roots compared to the hair roots. Generally extracellular root enzyme activity is not higher on ericaceous roots compared to ectomycorrhizas of Picea abies
Targeted Next-Generation Sequencing Reveals Novel RP1 Mutations in Autosomal Recessive Retinitis Pigmentosa
No full textBackground: Retinitis pigmentosa (RP) is a group of rare inherited retinal dystrophies that result in a progressive loss of vision. Molecular diagnosis of RP is difficult due to its phenotypic and genetic heterogeneities. Aims: To investigate causative genetic mutations in a collection of RP cases: one Indian and two Chinese families with autosomal-recessive RP and two sporadic patients with RP. Materials and Methods: A total of 163 genes, which have previously been found to be involved in inherited retinal disorders, were selected for targeted next-generation sequencing (NGS). Stringent NGS data analyses followed by confirmation using Sanger sequencing and segregation analyses were applied to evaluate all identified pathogenic mutations. Results: Four novel frameshift mutations and two compound heterozygous mutations were identified in RP1. In addition, all mutations were found to co-segregate with the disease in the three familial cases; none of the mutations were detected in control samples. Conclusion: This study expands the mutational spectrums of RP1 for RP
Female-female aggression functions in mate defence in an Asian agamid lizard
No full textFemale-female aggression and its functions are poorly understood compared with male-male aggression. Here, we examined the role of female-female aggression in mate defence in an Asian agamid lizard, Phrynocephalus vlangalii, in which male neighbours are valuable to females in both mating success and resource defence. We provided three social contexts by pairing a resident female with either a neighbour male, unfamiliar male or unfamiliar female, then introduced a tethered unknown female ( intruder). We carried out our experiments during and outside the mating season to test the links between female-female aggression and mate defence. The aggressive responses of resident females in these different social contexts were compared by quantifying variation in their territorial displays. Resident females were faster to display to the intruder in the presence of a neighbour male compared with both the unfamiliar male and female. We also found that female lizards signalled faster in the presence of the neighbour male than the other contexts, but only during the mating season. To separate the effects of familiarity from those of sex, we carried out a second experiment in which we paired a resident female with a neighbour male or neighbour female, before introducing a tethered unfamiliar female. In this experiment, resident females responded sooner to intruder females when paired with the neighbour male, although signalling speeds were equivalent. Taken together, our results suggest female-female aggression is used for both resource and mate defence, and so might be under direct selection. Our study highlights that female aggression more broadly requires further work. (C) 2017 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved
Soil bacterial community mediates the effect of plant material on methanogenic decomposition of soil organic matter
No full textInput of plant material may strongly change decomposition rates of soil organic matter (SOM), i.e. causing priming effect (PE), but the underlying mechanisms are largely unknown. We found that rice straw addition in anoxic Fuyang (F) rice field soil stimulated CH4 production from SOM at the expense of CO2, whereas in Uruguay (U) soil it suppressed SOM degradation to CO2 plus CH4 (negative PE). Reciprocal inoculation experiments with non-sterile and sterile soils showed that the soils always displayed the effect of rice straw characteristic for the live microbial commtmity rather than for the soil physicochemical properties. Pyrosequencing of 16S rRNA genes showed that bacterial communities in these soil samples were separated into two clusters (F and U). Symbiobacterium was abtmdant or dominant in microbiota from U soil, but negligible in those from F soil. Network analysis indicated that the bacterial populations involved in SOM decomposition were different between soils of F and U clusters; moreover, they were more tightly connected to methanogens in U than in F clusters. Ultimately, our results suggested that the PE of rice straw is mediated by the composition and activity of soil microbial community