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981.
982.
Jia Zhou Tiffanie Maree Nelson Carlos Rodriguez Lopez Roshmi Rekha Sarma Shao Jia Zhou Lee Ann Rollins 《Molecular ecology resources》2020,20(4):844-855
Noninvasive sampling methods for studying intestinal microbiomes are widely applied in studies of endangered species and in those conducting temporal monitoring during manipulative experiments. Although existing studies show that noninvasive sampling methods among different taxa vary in their accuracy, no studies have yet been published comparing nonlethal sampling methods in adult amphibians. In this study, we compare microbiomes from two noninvasive sample types (faeces and cloacal swabs) to that of the large intestine in adult cane toads, Rhinella marina. We use 16S rRNA gene sequencing to investigate how microbial communities change along the digestive tract and which nonlethal sampling method better represents large intestinal microbiota. We found that cane toads' intestinal microbiota was dominated by Bacteroidetes, Proteobacteria and Firmicutes and, interestingly, we also saw a high proportion of Fusobacteria, which has previously been associated with marine species and changes in frog immunity. The large and small intestine of cane toads had a similar microbial composition, but the large intestine showed higher diversity. Our results indicate that cloacal swabs were more similar to large intestine samples than were faecal samples, and small intestine samples were significantly different from both nonlethal sample types. Our study provides valuable information for future investigations of the cane toad gut microbiome and validates the use of cloacal swabs as a nonlethal method to study changes in the large intestine microbiome. These data provide insights for future studies requiring nonlethal sampling of amphibian gut microbiota. 相似文献
983.
The sensitivity of ABI2 to hydrogen peroxide links the abscisic acid-response regulator to redox signalling 总被引:1,自引:0,他引:1
ABI1 and ABI2 are two protein serine/threonine phosphatases of type 2C (EC 3.1.3.16) that act as key regulators in the responses of Arabidopsis thaliana (L.) Heynh. to abscisic acid (ABA). They are involved in the control of ABA-mediated seed dormancy, stomatal closure and vegetative growth inhibition. Analysis of the enzymatic properties of ABI2 revealed high sensitivities towards protons and unsaturated fatty acids. Furthermore, the protein phosphatase activity of ABI2 is very sensitive to H2O2, which has recently emerged as a secondary messenger of ABA signalling. Upon H2O2 challenge, ABI2 is rapidly inactivated with an IC50 value of 50 microM in the presence of reduced glutathione. Inhibitor studies with phenylarsine oxide and manipulation of the redox status of ABI2 in vitro indicate that oxidation of critical cysteine residue(s) is responsible for inactivation. The levels of the major cellular thiol compounds cysteine and glutathione in leaves and seedlings of A. thaliana are compatible with a physiological role of H2O2 in regulating ABI2 activity. ABI2 is considered to exert negative regulation on ABA action. Thus, transient inactivation of this protein phosphatase by H2O2 would allow or enhance the ABA-dependent signalling process. In conclusion, ABI2 represents a likely target for redox-regulation of a hormonal signalling pathway in higher plants. 相似文献
984.
C. R. Rodriguez‐Saona D. Polk R. Holdcraft A. M. Koppenhöfer 《Journal of Applied Entomology》2014,138(1-2):120-132
The oriental beetle, Anomala orientalis (Waterhouse) (Col., Scarabaeidae), is the most important root‐feeding pest of blueberries and turfgrass in New Jersey, USA. Previous studies showed that mating disruption is a feasible option for oriental beetle management; however, assessing its efficiency can be challenging, and little is known on its long‐term effects. Accordingly, we conducted studies to investigate low‐dose pheromone lures equivalent to oriental beetle females (i.e. female mimics) as easy‐to‐use indicators of mating disruption success, determine the distance at which oriental beetle males respond to female‐mimic lures and assess the long‐term (3‐year) effects of mating disruption on oriental beetle populations in entire blueberry fields. Our studies showed that rubber septa baited with 0.3 μg of the oriental beetle sex pheromone (Z)‐7‐tetradecen‐2‐one attract similar numbers of males as compared with virgin females and can thus be used as a female mimic. The range of attraction of this lure was found to be also similar to virgin females and <30 m. In blueberries, mating disruption provided 87% inhibition of oriental beetle populations (trap shutdown) over a 3‐year period. Oriental beetle male captures in disrupted fields were threefold higher along the field edges than in the field interiors, indicating movement of males from nearby areas into the pheromone‐treated fields. In addition, mating disruption reduced male attraction to female‐mimic lures by 93% in all 3 years and reduced the number of larvae in sentinel potted plants in 1 of 2 years. These results show for the first time that mating disruption provides consistent long‐term field‐wide control of oriental beetle populations and that female‐mimic pheromone lures can be used as a new tool to assess oriental beetle mating disruption success. 相似文献
985.
Olga P. Nyssen Angeles Perez‐Aisa Luis Rodrigo Manuel Castro Pilar Mata Romero Juan Ortuo Jesus Barrio Jose Maria Huguet Ines Modollel Noelia Alcaide Alfredo Lucendo Xavier Calvet Monica Perona Barbara Gomez Blas Jose Gomez Rodriguez Pilar Varela Manuel Jimenez‐Moreno Manuel Dominguez‐Cajal Liliana Pozzati Diego Burgos Luis Bujanda Jenifer Hinojosa Javier Molina‐Infante Tommaso Di Maira Luis Ferrer Luis Fernndez‐Salazar Ariadna Figuerola Llucia Tito Cristobal de la Coba Judith Gomez‐Camarero Nuria Fernandez Maria Caldas Ana Garre Elena Resina Ignasi Puig Colm OMorain Francis Megraud Javier P. Gisbert 《Helicobacter》2020,25(5)
986.
María-Carmen Rodriguez Yoldi José-Emilio Mesonero María-Jesús Rodriguez Yoldi 《Biological trace element research》1996,53(1-3):213-223
Zinc is a nutritionally essential trace element required for many biological functions to be succesfully carried out. The aim of the present work was to study the influence of zinc on the intestinal absorption of L-threonine and on the aminopeptidase N activity in rabbit jejunum, after in vitro addition and/or oral administration of ZnCl2 in drinking water. Results obtained show that zinc decreases L-threonine absorption in the jejunal tissue. This effect would appear to be owing to an action mainly located in active amino acid transport, because zinc does not seem to modify the amino acid diffusion across the intestinal epithelium, of the mucosal border of the intestinal epithelium. Zinc has also been shown to inhibit the (Na+?K+)-ATPase activity of the enterocyte, which might explain the inhibition of the L-threonine Na+-dependent transport. Nevertheless, a direct action of the zinc on carriers of active transport cannot be rejected. However, zinc did not significantly modify the aminopeptidase N activity in rabbit jejunum. 相似文献
987.
Chlorogenic acid modifies plasma and liver concentrations of: cholesterol,triacylglycerol, and minerals in (fa/fa) Zucker rats 总被引:1,自引:0,他引:1
Chlorogenic acid, a phenolic compound found ubiquitously in plants, is an in vitro antioxidant and metal chelator. Some derivatives of chlorogenic acid are hypoglycemic agents and may affect lipid metabolism. Concentrations of cholesterol and triacylglycerols are of interest due to their association with diseases such as non-insulin-dependent-diabetes- mellitus and obese insulin resistance. As little is known about the effects of chlorogenic acid in vivo, studies using obese, hyperlipidemic, and insulin resistant (fa/fa) Zucker rats were conducted to test the effect of chlorogenic acid on fasting plasma glucose, plasma and liver triacylglycerols and cholesterol concentrations. Aditionally, the effects of chlorogenic acid on selected mineral concentrations in plasma, spleen, and liver were determined. Rats were implanted with jugular vein catheters. Chlorogenic acid was infused (5 mg/Kg body weight/day) for 3 weeks via intravenous infusion. Chlorogenic acid did not promote sustained hypoglycemia and significantly lowered the postprandial peak response to a glucose challenge when compared to the same group of rats before Chlorogenic acid treatment. In Chlorogenic acid-treated rats, fasting plasma cholesterol and triacylglycerols concentrations significantly decreased by 44% and 58% respectively, as did in liver triacylglycerols concentrations (24%). We did not find differences (p > 0.05) in adipose triacylglycerols concentration. Significant differences (p < 0.05) in the plasma, liver, and spleen concentration of selected minerals were found in chlorogenic acid-treated rats. In vivo, chlorogenic acid was found to improve glucose tolerance, decreased some plasma and liver lipids, and improve mineral pool distribution under the conditions of this study. 相似文献
988.
Lei JT Mazumdar T Martinez-Moczygemba M 《The Journal of biological chemistry》2011,286(46):40091-40103
Eosinophils are multifunctional leukocytes implicated in the pathogenesis of numerous inflammatory diseases including allergic asthma and hypereosinophilic syndrome. Eosinophil physiology is critically dependent on IL-5 and the IL-5 receptor (IL-5R), composed of a ligand binding α chain (IL-5Rα), and a common β chain, βc. Previously, we demonstrated that the βc cytoplasmic tail is ubiquitinated and degraded by proteasomes following IL-5 stimulation. However, a complete understanding of the role of βc ubiquitination in IL-5R biology is currently lacking. By using a well established, stably transduced HEK293 cell model system, we show here that in the absence of ubiquitination, βc subcellular localization, IL-5-induced endocytosis, turnover, and IL-5R signaling were significantly impaired. Whereas ubiquitinated IL-5Rs internalized into trafficking endosomes for their degradation, ubiquitination-deficient IL-5Rs accumulated on the cell surface and displayed blunted signaling even after IL-5 stimulation. Importantly, we identified a cluster of three membrane-proximal βc lysine residues (Lys(457), Lys(461), and Lys(467)) whose presence was required for both JAK1/2 binding to βc and receptor ubiquitination. These findings establish that JAK kinase binding to βc requires the presence of three critical βc lysine residues, and this binding event is essential for receptor ubiquitination, endocytosis, and signaling. 相似文献
989.
Mónica Suárez Margarita Martín Estrella Ferrer Amando Garrido-Pertierra 《Archives of microbiology》1995,164(1):70-77
Unlike the parent wild-type strain, theKlebsiella pneumoniae mutant strain MAO4 has a 4-HBA+ phenotype. The capacity of this mutant to take up and metabolize 4-hydroxybenzoate (4-HBA) relies on the expression of a
permease and an NADPH-linked monooxygenase (4-HBA-3-hydroxylase). Both enzymes are normally expressed at basal levels, and
only the presence of 4-HBA in the media enhances their activities. Strikingly, when theAcinetobacter calcoaceticus pobA gene encoding 4-hydroxybenzoate-3-hydroxylase was expressed in hydroxybenzoateK. pneumoniae wild-type, the bacteria were unable to grow on 4-HBA, suggesting that the main difference between the wild-type and the mutant
strain is the capability of the latter to take up 4-HBA. 4-HBA-3-hydroxylase was purified to homogeneity by affinity, gel-filtration,
and anion-exchange chromatography. The native enzyme, which appeared to be a dimer of identical subunits, had an apparent
molecular mass of 80 kDa and a pI of 4.6. Steady-state kinetics were analyzed; the initial velocity patterns were consistent
with a concerted substitution mechanism. The purified enzyme had 362 amino acid residues, and a tyrosine seemed to be involved
in substrate activation. 相似文献
990.
Acosta-Rivero N Rodriguez A Musacchio A Falcón V Suarez VM Martinez G Guerra I Paz-Lago D Morera Y de la Rosa MC Morales-Grillo J Dueñas-Carrera S 《Biochemical and biophysical research communications》2004,325(1):68-74
Different variants of hepatitis C virus core protein (HCcAg) have proved to self-assemble in vitro into virus-like particles (VLPs). However, difficulties in obtaining purified mature HCcAg have limited these studies. In this study, a high degree of monomeric HCcAg purification was accomplished using chromatographic procedures under denaturing conditions. Size exclusion chromatography and sucrose density gradient centrifugation of renatured HCcAg (in the absence of structured RNA) under reducing conditions suggested that it assembled into empty capsids. The electron microscopy analysis of renatured HCcAg showed the presence of spherical VLPs with irregular shapes and an average diameter of 35nm. Data indicated that HCcAg monomers assembled in vitro into VLPs in the absence of structured RNA, suggesting that recombinant HCcAg used in this work contains all the information necessary for the assembly process. However, they also suggest that some cellular factors might be required for the proper in vitro assembly of capsids. 相似文献