Role of Carbonic Anhydrase IV in the Bicarbonate-Mediated Activation of Murine and Human Sperm

HCO3− is the signal for early activation of sperm motility. In vivo, this occurs when sperm come into contact with the HCO3− containing fluids in the reproductive tract. The activated motility enables sperm to travel the long distance to the ovum. In spermatozoa HCO3− stimulates the atypical sperm adenylyl cyclase (sAC) to promote the cAMP-mediated pathway that increases flagellar beat frequency. Stimulation of sAC may occur when HCO3− enters spermatozoa either directly by anion transport or indirectly via diffusion of CO2 with subsequent hydration by intracellular carbonic anhydrase (CA). We here show that murine sperm possess extracellular CA IV that is transferred to the sperm surface as the sperm pass through the epididymis. Comparison of CA IV expression by qRT PCR analysis confirms that the transfer takes place in the corpus epididymidis. We demonstrate murine and human sperm respond to CO2 with an increase in beat frequency, an effect that can be inhibited by ethoxyzolamide. Comparing CA activity in sperm from wild-type and CA IV−/− mice we found a 32.13% reduction in total CA activity in the latter. The CA IV−/− sperm also have a reduced response to CO2. While the beat frequency of wild-type sperm increases from 2.86±0.12 Hz to 6.87±0.34 Hz after CO2 application, beat frequency of CA IV−/− sperm only increases from 3.06±0.20 Hz to 5.29±0.47 Hz. We show, for the first time, a physiological role of CA IV that supplies sperm with HCO3−, which is necessary for stimulation of sAC and hence early activation of spermatozoa

Effect of allopurinol in addition to hypothermia treatment in neonates for hypoxic-ischemic brain injury on neurocognitive outcome (ALBINO): Study protocol of a blinded randomized placebo-controlled parallel group multicenter trial for superiority (phase III)

Background: Perinatal asphyxia and resulting hypoxic-ischemic encephalopathy is a major cause of death and long-term disability in term born neonates. Up to 20,000 infants each year are affected by HIE in Europe and even more in regions with lower level of perinatal care. The only established therapy to improve outcome in these infants is therapeutic hypothermia. Allopurinol is a xanthine oxidase inhibitor that reduces the production of oxygen radicals as superoxide, which contributes to secondary energy failure and apoptosis in neurons and glial cells after reperfusion of hypoxic brain tissue and may further improve outcome if administered in addition to therapeutic hypothermia. Methods: This study on the effects of ALlopurinol in addition to hypothermia treatment for hypoxic-ischemic Brain Injury on Neurocognitive Outcome (ALBINO), is a European double-blinded randomized placebo-controlled parallel group multicenter trial (Phase III) to evaluate the effect of postnatal allopurinol administered in addition to standard of care (including therapeutic hypothermia if indicated) on the incidence of death and severe neurodevelopmental impairment at 24 months of age in newborns with perinatal hypoxic-ischemic insult and signs of potentially evolving encephalopathy. Allopurinol or placebo will be given in addition to therapeutic hypothermia (where indicated) to infants with a gestational age 65 36 weeks and a birth weight 65 2500 g, with severe perinatal asphyxia and potentially evolving encephalopathy. The primary endpoint of this study will be death or severe neurodevelopmental impairment versus survival without severe neurodevelopmental impairment at the age of two years. Effects on brain injury by magnetic resonance imaging and cerebral ultrasound, electric brain activity, concentrations of peroxidation products and S100B, will also be studied along with effects on heart function and pharmacokinetics of allopurinol after iv-infusion. Discussion: This trial will provide data to assess the efficacy and safety of early postnatal allopurinol in term infants with evolving hypoxic-ischemic encephalopathy. If proven efficacious and safe, allopurinol could become part of a neuroprotective pharmacological treatment strategy in addition to therapeutic hypothermia in children with perinatal asphyxia. Trial registration: NCT03162653, www.ClinicalTrials.gov, May 22, 2017

Response of protozoan and microbial communities in various coniferous forest soils after transfer to forests with different levels of atmospheric pollution.

During recent decades, forest ecosystems have been exposed to high levels of atmospheric pollution, and it has been argued that this affects the composition and activity of decomposer communities and, subsequently, ecosystem functioning. To investigate the effects of atmospheric pollution on protozoa and microflora, a new experimental design was used. Undisturbed soil columns, originating from six coniferous forests across Europe and representing different stages of soil acidification, were transferred to two Scots pine forests (Fontainebleau and Wekerom) with different levels of N and S deposition (N

Oekologische und oekosystemanalytische Ansaetze fuer das Monitoring von gentechnisch veraenderten Organismen

Available from TIB Hannover: RN 8422(2002,44) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

The effects of ammonium sulphate deposition and root sinks on soil solution chemistry in coniferous forest soils

The effects of enhanced (NH4)(2)SO4 deposition on soil solution cation and anion concentrations and annual ionic fluxes were followed using a standardised experimental protocol in six European coniferous forests with contrasting soil types, pollution inputs and climate. Native soil cores containing a ceramic suction cup were installed in the field, roofed and watered every two weeks with local throughfall or local throughfall with added (NH4)(2)SO4 at 75 kg NH4+-N ha(-1) a(-1). Living root systems were established in half of the lysimeters. Untreated throughfall NH4+-N deposition at the sites ranged from 3.7 to 29 kg ha(-1) a(-1). Soil leachates were collected at two weekly intervals over 12 months and analysed for volume, and concentrations of major anions and cations. Increases in soil solution NO3- concentrations in response to N additions were observed after 4-9 months at three sites, whilst one sandy soil with high C:N ratio failed to nitrify under any of the treatments. Changes in NO3- concentrations in soil solution controlled soil solution cation concentrations in the five nitrifying soils, with Al3+ being the dominant cation in the more acid soils with low base saturation. The acidification responses of the soils to the (NH4)(2)SO4 additions were primarily related to the ability of the soils to nitrify the added NH4+. pH and soil texture seemed important in controlling NH4+ leaching in response to the treatments, with two less acidic, clay/clay loam sites showing almost total retention of added NH4+, whilst nearly 75% of the added N was leached as NH4+ at the acid sandy soils. The presence of living roots significantly reduced soil solution NO3- and associated cation concentrations at two of the six sites. The very different responses of the six soils to increased (NH4)(2)SO4 deposition emphasise that the establishment of N critical loads for forest soils need to allow for differences in N storage. capacity and nitrification potential

Ionic balances of forest soils reciprocally transplanted among sites with varying pollution inputs.

Forest ecosystems are currently being exposed to changes in chemical inputs and it is suggested that physical climate is also changing. A novel approach has been used to study the effects of ionic inputs and climatic conditions on forest soils by reciprocally exchanging lysimeters containing undisturbed soil columns between four forest sites in Europe. The soil columns contained no living roots and simulated a clear cut situation. The soils chosen represented different stages of acidification and were taken from sites along a transect of increasing exposure to acidic and nitrogen pollution. The purpose of the study was to quantify the reactions of soils when transferred to different environments. Element balances were used as an aggregated indicator to describe the reaction of the soil. The input of protons in local throughfall increased along the transect from 0.01 kmol h