Biology subjects

Qin, X.

Publications and source records attributed to Qin, X..

4 recordsLinked to original sources

bioRxiv2018

How do wind speed, release height, seed morphology interact to determine seed dispersal trajectory of Calligonum (Polygonaceae) species

How seed dispersal trajectory shifts with abiotic and biotic factors and what is the relationship between seed dispersal distance and dispersal trajectory are remain unclear. We used wind tunnel and video camera to track the seed dispersal trajectory of 7 Calligonum species with different appendages under the different wind speeds and the release heights. Dispersal trajectories and distances were determined by video analysis and spatial coordinate transformation. Based on perspective principle, 4 modes of trajectories were determined. Wind speed, seed mass and release height were the key factors determining seed dispersal trajectory modes. Release height and wind speed tended to have the strongest explanatory power on seeds with bristles and wings, respectively. Different trajectory modes lead to different dispersal distance, while the same dispersal distance can be the result of different trajectory modes. The proportion of species trajectory modes formed its trajectory spectrum. Wind speed tends to have strong influence on light and low-wind-loading seeds, release height tends to have that on heavy and high-wind-loading seeds. Species with high proportion of horizontal projectile and projectile have high dispersal capacity, vice versa. Therefore, trajectory spectrum of a species reveals its primary dispersal strategies and evolutionary consequences.

ecology↗

bioRxiv2018

Proteome and microbiota analysis reveals alterations of liver-gut axis under different stocking density of Peking ducks

The aim of this study was to determine the impact of stocking density on the liver proteome and cecal microbiota of Peking ducks. A total of 1,200 ducks with 21-day old were randomly allotted into 5 stocking density groups of 5, 6, 7, 8 and 9 ducks/m2, with 6 replicates for each group. At 40 days of age, duck serum and pectorals were collected for biochemical tests; liver and cecal contents of ducks were gathered for proteome and microbiota analysis, respectively. Serum MDA increased while pectorals T-AOC reduced linearly with enhancing stocking density. Duck lipid metabolism was altered under different stocking density as well. Serum LDL-C increased linearly with increasing stocking density. Proteome analysis revealed fatty acid biosynthesis proteins such as acyl-CoA synthetase family member 2 and fatty acid oxidation related proteins including acyl-CoA dehydrogenase long chain and acyl-coenzyme A oxidase were enriched in high stocking density group. Additionally, high stocking density increased oxidative response related proteins such as DDRGK domain containing 1 while diminished anti-oxidant capacity related proteins including regucalcin and catalase. 16S rDNA analysis revealed that higher stocking density was accompanied with decreased microbial diversity, as well as depletion of anti-inflammatory bacterial taxa, including Bacteroidales, Butyricimonas and Alistipe. In addition, decreased bile acid metabolism-associated bacteria such as Ruminococcaceae, Clostridiales and Desulfovibrionaceae were found in the high-density group. Both proteome and 16S rDNA results showed inflammation and chronic liver disease trend in the high-density group, which suggests the involvement of the liver-gut axis in oxidative stress.

microbiology↗

bioRxiv2018

Gut microbiota density influences host physiology and is shaped by host and microbial factors

To identify factors that regulate gut microbiota density and the impact of varied microbiota density on health, we assayed this fundamental ecosystem property in fecal samples across mammals, human disease, and therapeutic interventions. Physiologic features of the host (carrying capacity) and the fitness of the gut microbiota shape microbiota density. Therapeutic manipulation of microbiota density in mice altered host metabolic and immune homeostasis. In humans, gut microbiota density was reduced in Crohns disease, ulcerative colitis, and ileal pouch-anal anastomosis. The gut microbiota in recurrent Clostridium difficile infection had lower density and reduced fitness that were restored by fecal microbiota transplantation. Understanding the interplay between microbiota and disease in terms of microbiota density, host carrying capacity, and microbiota fitness provide new insights into microbiome structure and microbiome targeted therapeutics.

microbiology↗

bioRxiv2017

Divergent In vitro MIC Characteristics and underlying isogenic mutations in host-specialized Pseudomonas aeruginosa

Clinical isolates of Pseudomonas aeruginosa (Pa) from patients with cystic fibrosis (CF) are known to differ from those associated with infections of non-CF hosts in colony morphology, drug susceptibility patterns, and genomic hypermutability. Although Pa isolates from CF have long been recognized for their overall higher resistance rate calculated generally by reduced \"percent susceptible\", this study takes the approach to compare and contrast Etest MIC distributions between two distinct cohorts of clinical strains (n=224 from 56 CF patients and n=130 from 68 non-CF patients respectively) isolated in 2013. Logarithmic transformed MIC (logMIC) values of 11 antimicrobial agents were compared between the two groups. CF isolates tended to produce heterogeneous and widely dispersed MICs compared to non-CF isolates. By applying a test for equality of variances, we were able to confirm that the MICs generated from CF isolates against 9 out of the 11 agents were significantly more dispersed than those from non-CF (p<0.02-<0.001). Quantile-quantiles plots indicated little agreement between the two cohorts of isolates. Based on whole genome sequencing of 19 representative CF Pa isolates, divergent gain- or loss-of-function mutations in efflux and porin genes and their regulators between isogenic or intra-clonal associates were evident. Not one, not a few, but the net effect all adaptive mutational changes in the genomes of CF Pa, both shared and unshared between isogenic strains, are responsible for the divergent heteroresistance patterns. Moreover, the isogenic variations are suggestive of a bacterial syntrophic lifestyle when \"lockedo inside a host focal airway environment over prolonged periods.\n\nSignificance statementBacterial heteroresistance is associated with niche specialized organisms interacting with host species for prolonged period of time, medically characterized by \"chronic focal infections\". A prime example is found in Pseudomonas aeruginosa isogenic/non-homogeneous isolates from patient airways with cystic fibrosis. The development of pseudomonal polarizing MICs in vitro to many actively used antimicrobial agents among isogenic isolates and \"Eagle-type\" heteroresistance patterns are common and characteristic. Widespread isogenic gene lesions were evident for defects in drug transporters, DNA mismatch repair, and many other structural or cellular functions--a result of pseudomonal symbiotic response to host selection. Co-isolation of extremely susceptible and resistant isogenic Pa strains suggests intra-airway evolution of a multicellular syntrophic bacterial lifestyle, which has laboratory interpretation and clinical treatment implications.

microbiology↗