RESUMO
Black-faced impala (Aepyceros melampus ssp. petersi) are endemic to Namibia where conservation management involves immobilisation and translocation, and mortality with current protocols is common. Critically evaluated field immobilisation protocols are needed to maximise animal safety. This prospective study was done in two phases: the first compared etorphine- and thiafentanil-based combinations, the second evaluated the influence of oxygen in impala receiving the thiafentanil-based combination. Animals (10 per group) received 50 mg ketamine (K) and 10 mg butorphanol (B), with either 2.0 mg etorphine (E) or 2.0 mg thiafentanil (T). A third group of ten impala were anaesthetised using TKB with supplemental nasal oxygen (O) at a rate of 5 L/minute. Behavioural, metabolic and physiological variables were assessed within five minutes of recumbency and at 10, 15, and 20 minutes post-recumbency. Statistical analyses for non-parametric data were performed to compare the treatment groups as well as time points; p ≤ 0.05 considered significant. Following darting, 7/10 EKB animals were standing when approached, compared to 2/20 in the thiafentanil treatment groups. Time to first effect was significantly higher for EKB (155 ± 105.7 seconds) compared to TKBO (61.5 ± 21.4 seconds). Time to sternal after darting was significantly higher with EKB (411.6 ± 174 seconds) compared to TKB (160.5 ± 85.4 seconds) and TKBO (166 ± 77.3 seconds). This study builds on previous work investigating the effects of potent opioids on impala and is the first evaluating their use in a field setting. The thiafentanil combination had a faster onset and resulted in a smoother induction than the etorphine combination. Additionally, oxygenation improved in animals receiving oxygen supplementation.
RESUMO
Filipin was used as a cytochemical probe for membrane sterols in the root storage tissue of the red beet Beta vulgaris L. and the chloroplasts of Spinacia oleracea L. In unfixed beet tissue, filipin lysed the cells. Freeze-fracture replicas revealed that the filipin-sterol complexes were tightly aggregated in the plasma membrane, while in thin section the complexes corrugated the plasma membrane. If the cells were fixed with glutaraldehyde prior to the filipin treatment, the cell structure was preserved. Filipin-induced lesions were dispersed or clustered loosely in the plasma membrane. A few filipin-sterol complexes were observed in the tonoplast. In spinach chloroplasts, filipin-sterol complexes were limited to the outer membrane of the envelope and were not found in the inner membrane of the envelope or in the lamellar membranes. If the filipin-sterol complexes accurately mapped the distribution of membrane sterols, then sterol was located predominantly in the plasma membrane of the red beet and in the outer membrane of the chloroplast envelope. Furthermore, the sterol may be heterogenously distributed laterally in both these membranes.
RESUMO
The tonoplast of Saccharomyces cerevisiae contains regions depleted of intramembranous particles as the cells enter stationary phase. Freeze-fracture studies on intact cells from this growth stage show that a dispersed particle distribution predominates if the cell temperature is raised to 40 degrees C but that particle-depleted areas prevail at or below the cell growth temperature of 30 degrees C. Tonoplasts of isolated vacuoles also contain particle-depleted regions. Differential thermal analysis of lipids extracted from isolated vacuoles show an endothermic transition which encompasses the cell growth temperature. These results suggest that the tonoplast at this stage contains patches of gel-phase lipid and that these patches correspond to the intramembranous particle-depleted areas of the freeze-fractured tonoplast.
