Abstract MP10: Furin-Mediated Modification Is Required For Epithelial Sodium Channel-Activating Activity Of Soluble (Pro)Renin Receptor In Cultured Collecting Duct Cells

(Pro)renin receptor (PRR) contains overlapping cleavage site for site-1 protease (S1P) and furin for generation of soluble PRR (sPRR). Although S1P-mediated cleavage mediates the release of sPRR, the functional implication of furin-mediated cleavage is unclear. Here we tested whether furin-mediated cleavage was required for the activity of sPRR in activating ENaC in cultured M1 cells. M1 cells were transfected with pcDNA3.4 containing full-length PRR with (Furin Mut) or without (WT) mutagenesis of furin cleavage site; empty vector (EM) served a control. As compared with EM, overexpression of WT and Furin Mut vectors induced a more than 16-fold comparable increase in the release of sPRR. Amiloride-sensitive short circuit current as assessed by Ussing chamber technique was elevated by overexpression of WT PRR which was reduced by 37% by Furin Mut (ENaC activity: 1.00 + 0.06 μA/cm 2 in EM, 1.67 + 0.05 μA/cm 2 in WT, and 1.04 + 0.07 μA/cm 2 in Furin Mut, p < 0.05). In parallel, the expression of α-ENaC but not β or γ subunit as assessed by immunoblotting and qRT-PCR analysis was elevated by WT PRR and this increase was blunted by Furin Mut. In a separate experiment, M1 cells were transfected with pcDNA3.4 containing cDNA for sPRR with S1P cleavage (AA 1-282) (sPRR-S1P) or with furin cleavage (AA 1-279) (sPRR-furin); empty vector was used as a control. Overexpression of cDNA for the two types of sPRR induced a significant and comparable increase in the release of sPRR. By Ussing chamber technique, ENaC activity was 1.00 + 0.09 μA/cm 2 in EM, 1.03 + 0.10 μA/cm 2 in sPRR-S1P, and 1.39 + 0.14 μA/cm 2 in sPRR-furin, p < 0.05. Lastly, 293 cells were pretreated for 1 h with furin inhibitor α1-antitrypsin Portland followed by transfection with empty vector, WT PRR, or Furin Mut vectors. sPRR in the condition medium was enriched by using protein centrifugal filter devices and applied to M1 cells for 10 min followed by measurement of ENaC activity. Pretreatment with furin inhibition attenuated ENaC-acting activity induced by overexpression of WT PRR. Overall, the three independent approaches consistently demonstrated that furin-mediated modification is required for the activity of sPRR to increase ENaC-mediated Na + transport in the CD cells.

Wind Influences Corrected Auto-calibrated Soil Evapo-Respiration Chamber (ASERC), Evaporation Measures

The importance of the soil evaporation concerns our main life supports source for agriculture or for climate changes predictions science. A simple to operate instrument, based on non-steady state (NSS) technique, made for soil evaporation measurement appears then suitable. However, because the NSS chamber technique is highly invasive, special care should be provided to correct the wind influence on the evaporation process. As the wind influence on the evaporation is depending on numerous and not real-time monitorable variables, in order to make the measurements easily corrigible on a bare soil with a unique variable – wind speed (Ws), whatever is the soil nature, soil texture, and others soil or air meteorological variables – a self-calibrating chamber with corresponding protocol called Auto-calibrated Soil Evapo-Respiration Chamber (ASERC) was developed. A simple protocol followed by this chamber allows to determine the soil evaporation wind susceptibility (Z) and to correct the measurements achieving 0.95 accuracy confidence. Some interesting finding on sandy and clayey soils evaporation measured during a laboratory calibration will also be reported.

CO2 and Radon Emissions as Precursors of Seismic Activity

This paper reports a review on the relationship between seismic activity and the emissions of CO2 and radon. Direct, indirect and sampling methods are mainly employed to measure CO2 flux and concentration in seismic areas. The accumulation chamber technique is the mostly used in the literature. Radon gas emission in seismic areas can be considered as a short-term pre-seismic precursor. The study and the measurement of radon gas activity prior to earthquakes can be performed through active techniques, with the use of high-precision active monitors and through passive techniques with the use of passive detectors. Several investigators report models to explain the anomalous behavior of in-earth fluid gasses prior to earthquakes. Models are described and discussed.

Myxomycetes biodiversity in Gaziantep Province (Turkey) with four new records

Myxomycetes were cultured in moist chambers using substrate material collected in Gaziantep province, Turkey, during 2017–2019. Fruit bodies of wild myxomycetes were collected at ten locations. Rotten or live tree bark, leaves, debris, vegetable, and animal material, which were considered likely to contain spores, were also collected. Natural samples were immediately dried, and potential spore-bearing material was kept in a warm and humid environment with the moist chamber technique. A total of 537 samples were studied and 203 myxomycetes isolates were obtained, 33 of which were natural samples, 76 were obtained with the moist chamber technique and 94 were obtained both naturally and with the moist chamber technique in the laboratory. Six orders, 9 families, 16 genera and 42 species were identified in 3 subclasses. All species were new in Gaziantep province and four myxomycetes were identified as new records in Turkey; Didymium atrichum Henney & Alexop., Didymium serpula Fr., Craterium obovatum Peck and Physarum bivalve Pers. were added to the Turkish mycota.

Karakteristik Emisi CO2 Tanah Gambut di Bawah Tegakan Kelapa Sawit

Penelitian ini bertujuan mengkaji karakteristik emisi CO2 dari tanah gambut di bawah tegakan kelapa sawit yang dihubungkan dengan faktor lingkungan spesifik lokasi penelitian di daerah Kabupaten Labuhan Batu, Sumatera Utara. Gas CO2 diambil dengan menggunakan close chamber technique, sedangkan konsentrasi gas tersebut diukur menggunakan portable micro Gas Chromatograph CP 4900. Faktor lingkungan sebagai variabel bebas yang diamati meliputi suhu tanah (TS), suhu atmosfer (TA), kelembaban tanah lapisan 0 – 5 cm (SM5), kelembaban tanah lapisan 0 – 30 cm (SM30), dan pH gambut (A). Model hubungan CO2 dengan faktor dianalisis menggunakan analisis korelasi Spearman dan regresi multivariant. Analisis regresi multivariant dilakukan menggunakan regresi stepwise untuk mengetahui faktor lingkungan yang mempunyai hubungan dengan CO2 pada taraf beda nyata 5%. Analisis variance inflation factor (vif) dilakukan untuk melihat multicollinearity dari model regresi multivariant. Berdasarkan analisis korelasi Spearman, faktor lingkungan A (pH gambut) mempunyai koefisiensi korelasi yang tegolong sedang (R = 0.637). Hasil regresi stepwise menunjukkan bahwa emisi CO2 nyata dipengaruhi oleh kelembaban tanah SM30 dan A (n = 216; p < 0.05) dengan nilai vif <3. Regresi multivariant, menghasilkan persamaan terbaik (R2 = 0.420) dimana emisi CO2 = 7.394*A – 0.008*SM30 – 16.659. Secara parsial, penelitian ini juga memperoleh model hubungan emisi CO2 dengan kelembaban tanah gambut, dimana emisi CO2 tertinggi dicapai pada kondisi kelembaban tanah sekitar kapasitas lapang (354 – 376% w w-1) dan menurun dengan meningkatnya kelembaban tanah di atas kadar air kapasitas lapangan. Emisi CO2 tanah gambut mengalami penurunan pada kondisi tanah gambut mengering di bawah zone kadar air kritis, hal ini karena hidrofobisitas tanah gambut meningkat.