University of Extremadura

About: University of Extremadura is a education organization based out in Badajoz, Spain. It is known for research contribution in the topics: Population & Hyperspectral imaging. The organization has 7856 authors who have published 18299 publications receiving 396126 citations. The organization is also known as: Universidad de Extremadura.

Urinary bladder instability induced by selective suppression of the murine small conductance calcium-activated potassium (SK3) channel.

Abstract: Small conductance, calcium-activated potassium (SK) channels have an important role in determining the excitability and contractility of urinary bladder smooth muscle. Here, the role of the SK isoform SK3 was examined by altering expression levels of the SK3 gene using a mouse model that conditionally overexpresses SK3 channels (SK3T/T). Prominent SK3 immunostaining was found in both the smooth muscle (detrusor) and urothelium layers of the urinary bladder. SK currents were elevated 2.4-fold in isolated myocytes from SK3T/T mice. Selective suppression of SK3 expression by dietary doxycycline (DOX) decreased SK current density in isolated myocytes, increased phasic contractions of isolated urinary bladder smooth muscle strips and exposed high affinity effects of the blocker apamin of the SK isoforms (SK1-3), suggesting an additional participation from SK2 channels. The role of SK3 channels in urinary bladder function was assessed using cystometry in conscious, freely moving mice. The urinary bladders of SK3T/T had significantly greater bladder capacity, and urine output exceeded the infused saline volume. Suppression of SK3 channel expression did not alter filling pressure, threshold pressure or bladder capacity, but micturition pressure was elevated compared to control mice. However, SK3 suppression did eliminate excess urine production and caused a marked increase in non-voiding contractions. The ability to examine bladder function in mice in which SK3 channel expression is selectively altered reveals that these channels have a significant role in the control of non-voiding contractions in vivo. Activation of these channels may be a therapeutic approach for management of non-voiding contractions, a condition which characterizes many types of urinary bladder dysfunctions including urinary incontinence.

Effect of age on the enteric nervous system of the human colon

Abstract: The effect of age on the anatomy and function of the human colon is incompletely understood. The prevalence of disorders in adults such as constipation increase with age but it is unclear if this is due to confounding factors or age-related structural defects. The aim of this study was to determine number and subtypes of enteric neurons and neuronal volumes in the human colon of different ages. Normal colon (descending and sigmoid) from 16 patients (9 male) was studied; ages 33–99. Antibodies to HuC/D, ChAT, nNOS, and PGP9.5 were used. Effect of age was determined by testing for linear trends using regression analysis. In the myenteric plexus, number of Hu-positive neurons declined with age (slope = −1.3 neurons/mm/10yrs, p =0.03). The number of ChAT-positive neurons also declined with age (slope = −1.1 neurons/mm/10yrs of age, p=0.02). The number of nNOS-positive neurons did not decline with age. As a result, the ratio of nNOS to Hu increased (slope= 0.03 per 10yrs of age, p=0.01). In the submucosal plexus, the number of neurons did not decline with age (slope = − 0.3 neurons/mm/10 yrs, p =0.09). Volume of nerve fibers in the circular muscle and volume of neuronal structures in the myenteric plexus did not change with age. In conclusion, the number of neurons in the human colon declines with age with sparing of nNOS- positive neurons. This change was not accompanied by changes in total volume of neuronal structures suggesting compensatory changes in the remaining neurons.

Effects of Tillage, Crop Rotation, and Nitrogen Fertilization on Wheat under Rainfed Mediterranean Conditions

Abstract: The combined long-term effects of tillage method, crop rotation, and N fertilizer rates on grain yield have not been studied in rainfed systems under Mediterranean climates. As part of a long-term experiment started in 1986, a field study was conducted between 1994 and 1998 to determine the effects of tillage (TILL), crop rotation (ROT), and N fertilization on wheat (Triticum aestivum L.) growth and yield in a rainfed Mediterranean region. Tillage treatments included no tillage (NT) and conventional tillage (CT). Crop rotations were wheat-sunflower (Helianthus annuus L.) (WS), wheat-chickpea (Cicerarietinum L.) (WCP), wheat-faba bean (Vicia faba L.) (WFB), wheatfallow (WF), and continuous wheat (CW). Nitrogen fertilizer rates were 0, 50, 100, and 150 kg N ha -1 on a Vertisol (Typic Haploxerert). A split-split plot design with four replications was used. Heavy rainfall during this research negatively impacted vegetative growth and grain yield of the wheat due to waterlogging. Wheat yield in the wet years was lower under NT than under CT. Yield decreased in the following crop rotation sequence: WFB » WF > WS > WCP » CW. Wheat responded to N fertilizer at rates up to 100 kg N ha -1 in the wet years but exhibited no response in the dry years. Yield under CT was higher at all N rate applied to wheat. The effect of N fertilizer on yield was more marked for the rotations with no legumes. The incorporation of the results for the 4-yr period to those of the long-term experiment provides more consistent information on the characterization and performance of the various systems.

Cork Taint of Wines: Role of the Filamentous Fungi Isolated from Cork in the Formation of 2,4,6-Trichloroanisole by O Methylation of 2,4,6-Trichlorophenol

Abstract: Cork taint is a musty or moldy off-odor in wine mainly caused by 2,4,6-trichloroanisole (2,4,6-TCA). We examined the role of 14 fungal strains isolated from cork samples in the production of 2,4,6-TCA by O methylation of 2,4,6-trichlorophenol (2,4,6-TCP). The fungal strains isolated belong to the genera Penicillium (four isolates); Trichoderma (two isolates); and Acremonium, Chrysonilia, Cladosporium, Fusarium, Mortierella, Mucor, Paecilomyces, and Verticillium (one isolate each). Eleven of these strains could produce 2,4,6-TCA when they were grown directly on cork in the presence of 2,4,6-TCP. The highest levels of bioconversion were carried out by the Trichoderma and Fusarium strains. One strain of Trichoderma longibrachiatum could also efficiently produce 2,4,6-TCA in liquid medium. However, no detectable levels of 2,4,6-TCA production by this strain could be detected on cork when putative precursors other than 2,4,6-TCP, including several anisoles, dichlorophenols, trichlorophenols, or other highly chlorinated compounds, were tested. Time course expression studies with liquid cultures showed that the formation of 2,4,6-TCA was not affected by a high concentration of glucose (2% or 111 mM) or by ammonium salts at concentrations up to 60 mM. In T. longibrachiatum the O methylation of 2,4,6-TCP was catalyzed by a mycelium-associated S-adenosyl-l-methionine (SAM)-dependent methyltransferase that was strongly induced by 2,4,6-TCP. The reaction was inhibited by S-adenosyl-l-homocysteine, an inhibitor of SAM-dependent methylation, suggesting that SAM is the natural methyl donor. These findings increase our understanding of the mechanism underlying the origin of 2,4,6-TCA on cork, which is poorly understood despite its great economic importance for the wine industry, and they could also help us improve our knowledge about the biodegradation and detoxification processes associated with chlorinated phenols.