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Absorption of ammonia from the rumen of cattle decreases nitrogen availability for fermentational protein synthesis, leading to increased competition of cattle with humans for protein and enhancing the release of toxic nitrogenous compounds into the environment. Given that differences in feeding and breeding might induce differences in ruminal ammonia transport, we compared electrophysiological, histological, and molecular biological characteristics of ruminal epithelia of Bos indicus crossbreds (Sahiwal-Mix, SWM) with those of Bos taurus (Holstein-Friesian, HF). As in HF, the stratified cornified epithelium of SWM expressed claudin 1 and 4. Measurements of ammonia flux (HF) and serosal pH (both breeds) suggested that at a mucosal pH of 6.4, net transport primarily occurred as NH 4 + . As shown previously for HF, NH 4 + induced a concentration-dependent rise in short circuit current (I sc ) in SWM that could be further stimulated by the TRP channel agonist menthol. Relative mRNA expression levels for TRPV3, TRPV4, TRPM6, and TRPM7 were significantly lower in SWM than in HF, with TRPA1 expression near the limit of detection. We conclude that uptake of ammonia from the rumen of both breeds occurs electrogenically as NH 4 + with functional and molecular biological evidence pointing towards involvement of TRPV3 and TRPV4., (© 2018 Japanese Society of Animal Science.)

Background: Magnesium deficiency is a common complication of diabetes with an unclear molecular background., Objective: We investigated the effect of the insulin (INS)-signaling pathway (ISP) on the regulation of Mg(2+) efflux (Mg(2+)E) conducted by solute carrier family 41, member A1 (SLC41A1; activated by protein kinase A) in transgenic human embryonic kidney (HEK) 293 cells., Methods: HEK293 cells overexpressing SLC41A1 were loaded with the Mg(2+) fluorescent indicator mag-fura-2 and Mg(2+). Measurements of Mg(2+)E were conducted in Mg(2+)-free buffer by using fast-filter fluorescence spectrometry. We examined the effects of INS, inhibitors of ISP or p38 mitogen-activated protein kinase (p38 MAPK), an activator of adenylate cyclase (ADC), and their combinations on SLC41A1-attributed Mg(2+)E., Results: The application of 400 μU/mL INS inhibited SLC41A1-mediated Mg(2+)E by up to 50.6% compared with INS-untreated cells (P < 0.001). Moreover, INS evoked the early onset of Mg(2+) release from intracellular stores. The application of 0.1 μM wortmannin or 10 μM zardaverine (both ISP inhibitors) restored SLC41A1 Mg(2+)E capacity in the presence of INS to the same levels in INS-untreated cells. The simultaneous application of 10 μM forskolin, an ADC activator, and INS resulted in a reduction of Mg(2+)E of up to 59% compared with untreated cells (P < 0.001), which was comparable to that in cells treated with INS alone. Inhibition of p38 MAPK with 10 μM SB 202190 (SB) in the absence of INS resulted in a decrease (P < 0.001) of SLC41A1-dependent Mg(2+)E (by up to 49%) compared with Mg(2+)E measured in untreated cells. Simultaneous exposure of cells to SB and INS had a stronger inhibitory effect on SLC41A1 activity than INS alone (P < 0.05)., Conclusions: INS affects intracellular Mg(2+) concentration in transgenic HEK293 cells by regulating SLC41A1 activity (via ISP) and by influencing the compartmentalization and cellular distribution of Mg(2+). In addition, p38 MAPK activates SLC41A1 independently of INS action., (© 2015 American Society for Nutrition.)

Chromosome profiles of 10 Trypanosoma (T.) congolense populations with different isometamidium sensitivities were compared using the pulsed field gel electrophoresis technique. The aim was to elucidate whether there was a karyotype pattern specific to eight isometamidium resistant phenotypes. Analysis of the profiles indicated that all populations displayed several discrete bands at the region of small, intermediate and large chromosomes. The highest similarity was observed between two isolates originating from Burkina Faso, indicating that they had the same genetic origin. Other eight strains exhibited different patterns in terms of chromosome size and numbers such that there was no characteristic karyotype pattern that was established specifically to identify resistant populations and discriminate them from the sensitive ones. This study has revealed that isometamidium resistance is not correlated to karyotype profile in T. congolense.

We have studied the transport of acetate across the isolated epithelium of sheep omasum; no net transport was observed (J(ms) approximately = J(sm)) under Ussing chamber conditions. Low mucosal pH (pH 6.4) significantly enhanced J(ms) acetate and the transport rates of acetate increased linearly and significantly (r2=0.99) with the luminal acetate concentration. The presence of another short chain fatty acid (propionate) did not affect J(ms) acetate significantly. Neither addition of 1 mmol l(-1) DIDS to the mucosal side nor HCO3 replacement caused changes of J(ms) acetate; this does not support the assumption of acetate transport via anion exchange. Addition of 1 mmol l(-1) amiloride to the mucosal side significantly decreased acetate fluxes at high mucosal acetate concentration (100 mmol l(-1)) and low pH (6.4) indicating interaction between acetate uptake in the undissociated form, intracellular release of protons and activation of Na+/H+ exchange (NHE). However, the mutual interaction between Na transport via NHE and acetate transport is asymmetric. Stimulation or inhibition of Na transport via NHE is much more pronounced than the corresponding changes of acetate fluxes. Thus, the obtained results support the conclusion that acetate is transported via simple diffusion and probably predominantly in the protonated form, thereby explaining the positive and mutual interaction between Na transport and short chain fatty acids.

Water, methanol and dichloromethane extracts prepared from various parts of 40 medicinal plant species from Mali were investigated for their trypanocidal activity against Trypanosoma brucei brucei. Of a total of 165 extracts tested in vitro in the Low Inoculation Long Incubation Test (LILIT), 24 extracts showed a high trypanocidal activity. Using the Long-Term Viability Assay (LtVA) for corroboration of the results of the 24 extracts, it was found that 15 samples had minimum inhibitory concentration (MIC) values > 10 microg/ml, eight MIC values of 100 microg/ml and one MIC values of 50-100 microg/ml. So far, four extracts with MIC values < or = 100 microg/ml were tested for antitrypanosomal activity in mice, experimentally infected with Trypanosoma brucei brucei. Only, the aqueous extracts of the leaves of Terminalia avicennioides Guill. and Perr. (Combretaceae) and the stem bark of Ceiba pentandra (L.) Gaertn. (Bombacaceae) were able to reduce the parasitaemia in animals treated at the dose of 100 mg/kg b.w. (intraperitoneally, two times daily for 3 days) and of 150 mg/kg b.w. (per os, two times daily for 3 days), respectively. The reduction of parasitaemia was, however, statistically significant (p=0.002) only in case of treatment with Terminalia avicennioides.

Blood was collected from two Sahelian goats, experimentally infected with either a drug-sensitive cloned population of Trypanosoma congolense (IL 1180) or a multiple drug-resistant T. congolense stock (Samorogouan/89/CRTA/267) and incubated at 37 degrees C for 30 min and 12 h, respectively, in the presence of different drug concentrations (0.5, 1.0, 10.0 and 100.0 microg/ml blood) of diminazene aceturate or isometamidium chloride. After that, the trypanosome/blood/drug suspensions were offered to tsetse flies (2100 teneral Glossina morsitans submorsitans) through an in vitro feeding system, using a silicone membrane. All tsetse flies were dissected and examined for the presence of trypanosomes in labrum, hypopharynx and midgut 20 days after their infective blood-meals. Infectivity of the drug-sensitive cloned population was already completely abolished after incubation with 0.5 microg/ml of both drugs; however, 13.6-42.2% of tsetse having been fed on untreated blood had developed an infection. In contrast, no significant differences were observed in the infection rates between the experimental groups and their control groups when fed on blood infected with the multiple drug-resistant stock after incubation for 30 min with up to 10 microg/ml of diminazene or isometamidium. In consequence, tsetse appear to be a useful tool in the assessment of drug susceptibility of typanosome populations.