Canopy CO2 concentrations and Crassulacean acid metabolism in Hoya carnosa in a subtropical rain forest in Taiwan: consideration of CO2 avallability and the evolution of CAM in epiphytes

The potential importance of CO2 derived from host tree respiration at night as a substrate for night time CO2 uptake during CAM was investigated in the subtropical and tropical epiphytic vine Hoya carnosa in a subtropical rainforest in north-eastern Taiwan. Individuals were examined within the canopies of host trees in open, exposed situations, as well as in dense forests. Although night time CO2 concentrations were higher near the epiphytic vines at night, relative to those measured during the day, presumably the result Of CO2 added to the canopy air by the host tree, no evidence for substantial use of this CO2 was found. In particular, stable carbon isotope ratios of H. carnosa were not substantially lower than those of many other CAM plants, as would be expected if host-respired CO2 were an important source Of CO2 for these CAM epiphytes. Furthermore, laboratory measurements of diel CO2 exchange revealed a substantial contribution of daytime CO2 uptake in these vines, which should also result in lower carbon isotope values than those characteristic of a CAM plant lacking daytime CO2 uptake. Overall, we found that host-respired CO2 does not contribute substantially to the carbon budget of this epiphytic CAM plant. This finding does not support the hypothesis that CAM may have evolved in tropical epiphytes in response to diel changes in the CO2 concentrations within the host tree canopy

Characterization of 13 multi-drug resistant Salmonella serovars from different broiler chickens associated with those of human isolates

<p>Abstract</p> <p>Background</p> <p><it>Salmonella </it>are frequently isolated from chickens and their products. Prevalent serogroups and serovars of <it>Salmonella </it>as well as their genotypes and antibiograms were determined for cloacal samples from 1595 chickens. To understand the possible serovar and H antigens for transmission between chicken and human, serovars and their H antigens of 164 chicken and 5314 human isolates were compared.</p> <p>Results</p> <p>Prevalence of <it>Salmonella </it>differed among chicken lines and ages. Chicken and human isolates belonged mainly to serogroup B, C1, C2-C3, D, and E. 13 serovars and 66 serovars were identified for chicken and human isolates respectively. The common serovars for chicken and human isolates were <it>S</it>. Typhimurium, <it>S</it>. Enteritidis, <it>S</it>. Albany, <it>S</it>. Derby, and <it>S</it>. Anatum and shared common H1 antigens "g complex; i; e,h; and z4,z24" and H2 antigens "1 complex and -". In human isolates, H1 antigen "i" and H2 antigen "-" were common in all serogroups. In chicken, antimicrobial susceptibility differed among serogroups, serovars and three counties. All isolates were susceptible to cefazolin and ceftriaxone, but highly resistant to ampicillin, chloramphenicol, flumequine, streptomycin, sulfamethoxazole-trimethoprim, and tetracycline. Except those isolates of serogroup C1 of Chick group and serogroup G, all isolates were multi-drug resistance. Only <it>S</it>. Kubacha, <it>S</it>. Typhimurium, <it>S</it>. Grampian, and <it>S</it>. Mons were resistant to ciprofloxacin and/or enrofloxacin.</p> <p>Conclusion</p> <p>In chicken, prevalent serogroups and serovars were associated with chicken ages, lines and regions; and flouroquinolone-resistant and MDR isolates emerged. H1 antigens "g complex and i" and H2 antigens "1 complex and -" might be important for transmission of <it>Salmonella </it>between chicken and human.</p

Integrated analyses of single-cell atlases reveal age, gender, and smoking status associations with cell type-specific expression of mediators of SARS-CoV-2 viral entry and highlights inflammatory programs in putative target cells

The COVID-19 pandemic, caused by the novel coronavirus SARS-CoV-2, creates an urgent need for identifying molecular mechanisms that mediate viral entry, propagation, and tissue pathology. Cell membrane bound angiotensin-converting enzyme 2 (ACE2) and associated proteases, transmembrane protease serine 2 (TMPRSS2) and Cathepsin L (CTSL), were previously identified as mediators of SARS-CoV2 cellular entry. Here, we assess the cell type-specific RNA expression of ACE2, TMPRSS2, and CTSL through an integrated analysis of 107 single-cell and single-nucleus RNA-Seq studies, including 22 lung and airways datasets (16 unpublished), and 85 datasets from other diverse organs. Joint expression of ACE2 and the accessory proteases identifies specific subsets of respiratory epithelial cells as putative targets of viral infection in the nasal passages, airways, and alveoli. Cells that co-express ACE2 and proteases are also identified in cells from other organs, some of which have been associated with COVID-19 transmission or pathology, including gut enterocytes, corneal epithelial cells, cardiomyocytes, heart pericytes, olfactory sustentacular cells, and renal epithelial cells. Performing the first meta-analyses of scRNA-seq studies, we analyzed 1,176,683 cells from 282 nasal, airway, and lung parenchyma samples from 164 donors spanning fetal, childhood, adult, and elderly age groups, associate increased levels of ACE2, TMPRSS2, and CTSL in specific cell types with increasing age, male gender, and smoking, all of which are epidemiologically linked to COVID-19 susceptibility and outcomes. Notably, there was a particularly low expression of ACE2 in the few young pediatric samples in the analysis. Further analysis reveals a gene expression program shared by ACE2(+)TMPRSS2(+) cells in nasal, lung and gut tissues, including genes that may mediate viral entry, subtend key immune functions, and mediate epithelial-macrophage cross-talk. Amongst these are IL6, its receptor and co-receptor, IL1R, TNF response pathways, and complement genes. Cell type specificity in the lung and airways and smoking effects were conserved in mice. Our analyses suggest that differences in the cell type-specific expression of mediators of SARS-CoV-2 viral entry may be responsible for aspects of COVID-19 epidemiology and clinical course, and point to putative molecular pathways involved in disease susceptibility and pathogenesis

Wake flow pattern modified by small control cylinders at low Reynolds number

Passive wake control behind a circular cylinder in uniform flow is studied by numerical simulation for Re-D ranging from 80 to 300. Two small control cylinders, with diameter d/D = 1/8, are placed at x/D = 0.5 and y/D = +/- 0.6. Unlike the 1990 results of Strykowski and Sreenivasan, in the present study, the vortex street behind the main cylinder still exists but the fluctuating lift and the form drag on the main cylinder reduces significantly and monotonously as the Reynolds number increases from 80 to 300. Obstruction of the control cylinders to the incoming flow deflects part of the fluid to pass through the gap between the main and control cylinders, forming two symmetric streams. These streams not only eliminate the flow separation along the rear surface of the main cylinder, they also merge toward the wake centerline to create an advancing momentum in the immediate near-wake region. These two effects significantly reduce the wake width behind the main cylinder and lead to monotonous decrease of the form drag as the Reynolds number increases. As the Reynolds number gets higher, a large amount of the downstream advancing momentum significantly delays the vortex formation farther downstream, leading to a more symmetric flow structure in the near-wake region of the main cylinder. As the Reynolds number increases from 80 to 300, both increasing symmetry of the flow structure in the near-wake and significant delay of the vortex formation are the main reasons for the fluctuating lift to decrease monotonously. (c) 2007 Elsevier Ltd. All rights reserved

Experimental investigation of a parallel vortex-plate interaction

The interaction of a spanwise vortex with a flat plate was investigated experimentally in a wind tunnel. The vortex was produced by a vortex generator airfoil pitching in a tailored nonsinusoidal schedule. The smoke-wire visualization technique and unsteady surface pressure measurements were used to examine the interaction for plates having different leading-edge configurations. The results focus on transient variations of the flow structure and pressure distribution over the plate with the vortex position during the interaction. In comparison with the sharp and elliptical leading-edge plates, it was found that the passage of the vortex has a much stronger effect on the amplitude of unsteady loading for the plate with a square leading edge, primarily due to the deformation of the leading-edge separation bubble. For the examined range of vertical separation distance between the incident vortex and the test plate, it was also found that the amplitude of plate lift variation during the interaction decreases approximately linearly with the separation distance. (C) 1998 Academic Press Limited

Effects of xylanase supplementation to wheat-based diet on the performance and nutrient availability of broiler chickens

A trial was conducted to evaluate the level of wheat substituted for corn in a traditional corn-soy diet and the xylanase supplementation effect on the growth performance and nutrient digestion of broiler chickens. This experiment was a randomized design with a 4x2 factorial arrangement with four levels of wheat substitution and two levels of enzyme inclusion in the diet. Wheat replaced 0, 25, 50 or 100% corn with or without 1 g/kg xylanase supplementation in iso-nitrogenous and iso-calorific experimental diets. The results showed that in the growing period, broilers attained the highest (p < 0.05) body weight gain, feed intake, and relative small intestine weight when wheat was substituted at 25% for corn. The relative caecum weight increased (p < 0.05) linearly with increasing levels of wheat substitution for corn. However, during the finishing period and entire experimental period from 0 to 6 weeks, no significant difference was shown in the growth performance among all treatments. Xylanase inclusion significantly improved the body weight gain, fat availability (p < 0.01) and diet metabolisable energy (p < 0.1) but decreased (p < 0.05) the relative GI tract weight during the growing period. The digesta viscosity of 6-week old broilers was also decreased (p < 0.05). It appears that wheat substituted for corn did not affect the growth performance, nutrient digestion, and the digesta viscosity of chickens. It is acceptable to completely substitute wheat for corn. Xylanase supplementation improved performance

Evaluating Nutritional Quality of Single Stage- and Two Stage-fermented Soybean Meal

This study investigated the nutritional quality of soybean meal (SBM) fermented by Aspergillus (FSBM(A)) and/or followed by Lactobacillus fermentation (FSBM(A+L)). Both fermented products significantly improved protein utilization of SBM with higher trichloroacetic acid (TCA) soluble true protein content, in vitro protein digestibility and available lysine content, especially in FSBM(A+L). Moreover, FSBM(A+L) produced a huge amount of lactic acid resulting in lower pH as compared to the unfermented SBM or soybean protein concentrate (SPC) (p55 kDa, mainly beta-conglycinin) decreased to 9.4%, 5.4% and increased to 38.8%, respectively. There were no significant differences in ileal protein digestibility regardless of treatment groups. SPC inclusion in the diet showed a better protein digestibility than the SBM diet. In summary, soybean meal fermented by Aspergillus, especially through the consequent Lactobacillus fermentation, could increase the nutritional value as compared with unfermented SBM and is compatible with SPC

Effect of caponization and exogenous androgens implantation on blood lipid and lipoprotein profile in male chickens

This study investigated effects of caponization and different forms of androgen implantation on blood lipid and lipoprotein profile of capons to understand the role of different androgens. Male chickens were caponized at 12 wk of age and selected at 16 wk of age for a 10-wk feeding period. Sixteen intact caponized (capon) male chickens and 16 female chickens were assigned for trial 1, and 16 sham-operated (sham) male chickens and 64 capons were selected for trial 2, in which capons were randomly divided into cholesterol (CHOL), testosterone (TES), 5 alpha-dihydrotestosterone, or 19-nortestosterone (19-NorT) implantation at 16, 20, and 24 wk of age. Trial 1 showed that caponization decreased TES concentration (P 0.05). Caponization increased lipoprotein lipase (LPL) activity and relative abdominal fat weight (P 0.05). Caponization also increased low-density lipoprotein (LDL) content and LDL-protein percentage (P 0.05). Cholesterol implantation increased LPL activity compared with the sham (P 0.05). Different levels of androgen implantation also demonstrated changes in LDL triacylglyceride and protein percentage and reached a level compatible with the sham (P > 0.05). Caponization decreased blood TES concentration in male chickens, increased LPL activity, and changed the lipoprotein composition, leading to an increase in abdominal fat weight. Results of different androgen implantations in capons demonstrated no difference in lipoprotein profile between androgens, but 19-NorT performed most effectively in abdominal fat accumulation recovery