Cotton AnnGh3 Encoding an Annexin Protein is Preferentially Expressed in Fibers and Promotes Initiation and Elongation of Leaf Trichomes in Transgenic Arabidopsis

The annexins are a multifamily of calcium-regulated phospholipid-binding proteins. To investigate the roles of annexins in fiber development, four genes encoding putative annexin proteins were isolated...     

Global Validation of a Process-Based Model on Vegetation Gross Primary Production Using Eddy Covariance Observations

Gross Primary Production (GPP) is the largest flux in the global carbon cycle. However, large uncertainties in current global estimations persist. In this study, we examined the performance of a process-based model (Integrated BIosphere Simulator, IBIS) at 62 eddy covariance sites around the world. Our results indicated that the IBIS model explained 60% of the observed variation in daily GPP at all validation sites. Comparison with a satellite-based vegetation model (Eddy Covariance-Light Use Efficiency, EC-LUE) revealed that the IBIS simulations yielded comparable GPP results as the EC-LUE model. Global mean GPP estimated by the IBIS model was 107.50±1.37 Pg C year⁻¹ (mean value ± standard deviation) across the vegetated area for the period 2000–2006, consistent with the results of the EC-LUE model (109.39±1.48 Pg C year⁻¹). To evaluate the uncertainty introduced by the parameter V_cmax, which represents the maximum photosynthetic capacity, we inversed V_cmax using Markov Chain-Monte Carlo (MCMC) procedures. Using the inversed V_cmax values, the simulated global GPP increased by 16.5 Pg C year⁻¹, indicating that IBIS model is sensitive to V_cmax, and large uncertainty exists in model parameterization.     

The responses of photosynthetic rate and stomatal conductance of Fraxinus rhynchophylla to differences in CO2 concentration and soil moisture

The photosynthetic parameters in leaves of three-year-old seedlings of Fraxinus rhynchophylla L. were studied under different soil water conditions and CO₂ concentrations ([CO₂]) with a LI-COR 6400 portable photosynthesis system. The objective was to investigate the response of photosynthesis and stomatal conductance (g _s) to various [CO₂] and soil water conditions, and to understand the adaptability of F. rhynchophylla to such conditions. The results showed that the soil water content (RWC) required to maintain high photosynthetic productivity in F. rhynchophylla was 49.5–84.3%; in this range, net photosynthetic rate (P _N) rose with [CO₂] increasing from 500 to 1,400 μmol mol^?1. Outside this RWC range, P _N decreased significantly. The apparent maximum photosynthetic rate (P _max,c) and carboxylation velocity (V _c) increased with increasing RWC and remained relatively high, when RWC was between 49.5 and 96.2%. CO₂ compensation points and photorespiration rate exhibited a trend opposite to that of P _max,c and V _c, indicating that moderate water stress was beneficial for increasing plant assimilation, decreasing photorespiration, and increasing production of photosynthates. g _s declined significantly with increasing [CO₂] under different water supplies, but the RWC range maintaining high g _s increased. g _s reached its maximum, when RWC was approximately 73% and then decreased with declining RWC. The maximal g _s was found with increasing RWC. Thus, based on photosynthetic characteristics in artificial, vegetation construction in semiarid loess hill and gully area, F. rhynchophylla could be planted in habitats of low soil water content.     

Choline kinase alpha 2 acts as a protein kinase to promote lipolysis of lipid droplets

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Delta-secretase triggers Alzheimer’s disease pathologies in wild-type hAPP/hMAPT double transgenic mice

Alzheimer’s disease (AD) is the most common neurodegenerative disease with multifactorial pathologies including Aβ containing senile plaques and neurofibrillary tangles (NFT) consisted of aggregated Tau. Most of the AD patients are sporadic and the familial mutation hereditary patients are composed only 1% of all cases. However, the current AD mouse models employ mutated APP, PS1, or even Tau mutant, in order to display a portion of AD pathologies. Delta-secretase (legumain, or asparaginyl endopeptidase, AEP) simultaneously cleaves both APP and Tau and augments Aβ production and Tau hyperphosphorylation and aggregation, contributing to AD pathogenesis. Here we show that δ-secretase is sufficient to promote prominent AD pathologies in wild-type hAPP/hMAPT double transgenic mice. We crossed hAPP l5 mice and hMAPT mice to generate double transgenic mouse model carrying both human wild-type APP and Tau. Compared to the single transgenic parents, these double transgenic mice demonstrated AD-related pathologies in one-year-old hAPP/hMAPT mice. Notably, overexpression of δ-secretase in hAPP/hMAPT double-transgenic mice evidently accelerated enormous senile plaques and NFT, associated with prominent synaptic defects and cognitive deficits. Hence, δ-secretase facilitates AD pathogenesis independent of any patient-derived mutation.Subject terms: Alzheimer''s disease, Neurological disorders     

Geographic patterns of Lucanus (Coleoptera: Lucanidae) species diversity and environmental determinants in China

Clarifying the geographic patterns of species diversity and the determinant factors can provide essential information for species conservation and management. Stag beetles (Coleoptera: Lucanidae) of Lucanus are important saproxylic insects and can be used for biomonitoring forests. Most of Lucanus species are facing conservation concerns due to their limited distribution and fragmented habitats, particularly in China, which has the richest species diversity of this genus. The distribution patterns of species diversity of Lucanus at large spatial scales remain portly understood. We studied the distribution patterns of Lucanus and its environmental and geographic determinants in China. Distribution data for 72 species and subspecies were examined. All these species are distributed in southern China except for Lucanus maculifemoratus dybowskyi, which is mainly distributed in north China. The hotspot for Lucanus in China is southeastern Tibet. Our study indicated that the species richness of Lucanus in China was shaped by the precipitation of the wettest and driest month, net primary productivity, digital elevation model, and latitude at a large scale. These variables collectively explained 56.2% of the variation in species richness; precipitation contributed the most (44.1%). Our results provide valuable insights to improve the conservation of Lucanus and can contribute to furthering our understanding of the biogeography of stag beetles in China.

We describe the diversity of the stag beetle species and further explore its formation. The result indicated that the variables of geography vegetation, temperature, and precipitation collectively shaped the distributed pattern, and geographical variables are most important.     

Survivorship of geographic Pomacea canaliculata populations in responses to cold acclimation

1. Pomacea canaliculata, a freshwater snail from South America, has rapidly established natural populations from south to north subtropical region in China, since its original introductions in the 1980s. Low temperature in winter is a limiting factor in the geographic expansion and successfully establishment for apple snail populations. There have been some studies on population level of low temperature tolerance for P. canaliculata, yet little is quantified about its life‐history traits in responses to cold temperatures. Whether these responses vary with the acclimation location is also unclear. We investigated the survivorship and longevity of P. canaliculata in responses to cold temperatures and examine whether these responses vary with the location and snail size. We hypothesized that survival of the snails depends on their shell height and the level of low temperature, and P. canaliculata population from the mid-subtropical zone may exhibit the highest viability over the cold thermal range.
2. We sampled P. canaliculata populations from five latitude and longitude ranges of subtropical China: Guangzhou population in southernmost (SM‐GZ), three populations of Yingtan (MR‐YT), Ningbo (MR‐NB), Ya'an (MR‐YA) in midrange, and Huanggang population in northernmost (NM‐HG) subtropical zone. For each P. canaliculata population, survival and longevity at six cold acclimation temperature levels (12, 9, 6, 3, 0, and ?3°C) were quantified, and the effects of location and shell height were examined.
3. The MR‐YA population from mid-subtropical zone of China exhibited the highest survival rate and prolonged survival time regardless of the temperature acclimation treatments, whereas the SM‐GZ population from southern subtropical was the most sensitive to cold temperatures, particular temperatures below 9°C. No individuals of the SM‐GZ population could survive after stressed for 30 days (3°C), 5 days (0°C) and 2 days (?3°C), respectively. For each experimental P. canaliculata population held at 3, 0, and ?3°C, individuals with intermediate shell height of 15.0–25.0 mm had significantly higher survivals.
4. The results highlight a request of a more thorough investigation on acclimation responses in each of the life table demographic parameters for P. canaliculata, and pose the question of whether natural selection or some genetic changes may have facilitated adaptation in invasive locations.

     

Identification of compound heterozygous DNAH11 variants in a Han-Chinese family with primary ciliary dyskinesia

Primary ciliary dyskinesia (PCD) is a group of genetically and clinically heterogeneous disorders with motile cilia dysfunction. It is clinically characterized by oto-sino-pulmonary diseases and subfertility, and half of the patients have situs inversus (Kartagener syndrome). To identify the genetic cause in a Han-Chinese pedigree, whole-exome sequencing was conducted in the 37-year-old proband, and then, Sanger sequencing was performed on available family members. Minigene splicing assay was applied to verify the impact of the splice-site variant. Compound heterozygous variants including a splice-site variant (c.1974-1G>C, rs1359107415) and a missense variant (c.7787G>A, p.(Arg2596Gln), rs780492669), in the dynein axonemal heavy chain 11 gene (DNAH11) were identified and confirmed as the disease-associated variants of this lineage. The minigene expression in vitro revealed that the c.1974-1G>C variant could cause skipping over exon 12, predicted to result in a truncated protein. This discovery may enlarge the DNAH11 variant spectrum of PCD, promote accurate genetic counselling and contribute to PCD diagnosis.     

Development and Validation of a UPLC-MS/MS Method to Monitor Cephapirin Excretion in Dairy Cows following Intramammary Infusion

Cephapirin, a cephalosporin antibiotic, is used by the majority of dairy farms in the US. Fecal and urinary excretion of cephapirin could introduce this compound into the environment when manure is land applied as fertilizer, and may cause development of bacterial resistance to antibiotics critical for human health. The environmental loading of cephapirin by the livestock industry remains un-assessed, largely due to a lack of appropriate analytical methods. Therefore, this study aimed to develop and validate a cephapirin quantification method to capture the temporal pattern of cephapirin excretion in dairy cows following intramammary infusion. The method includes an extraction with phosphate buffer and methanol, solid-phase extraction (SPE) clean-up, and quantification using ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The LOQ values of the developed method were 4.02 µg kg⁻¹ and 0.96 µg L⁻¹ for feces and urine, respectively. This robust method recovered >60% and >80% cephapirin from spiked blank fecal and urine samples, respectively, with acceptable intra- and inter-day variation (<10%). Using this method, we detected trace amounts (µg kg⁻¹) of cephapirin in dairy cow feces, and cephapirin in urine was detected at very high concentrations (133 to 480 µg L⁻¹). Cephapirin was primarily excreted via urine and its urinary excretion was influenced by day (P = 0.03). Peak excretion (2.69 mg) was on day 1 following intramammary infusion and decreased sharply thereafter (0.19, 0.19, 0.08, and 0.17 mg on day 2, 3, 4, and 5, respectively) reflecting a quadratic pattern of excretion (Quadratic: P = 0.03). The described method for quantification of cephapirin in bovine feces and urine is sensitive, accurate, and robust and allowed to monitor the pattern of cephapirin excretion in dairy cows. This data will help develop manure segregation and treatment methods to minimize the risk of antibiotic loading to the environment from dairy farms.