Evaluation of Cheetah and Leopard Spermatozoa Developmental Capability after Interspecific ICSI with Domestic Cat Oocytes

The ICSI procedure is potentially of great value for felids, and it has not been extensively studied in these species. The objectives of this work were to determine the best conditions for ICSI in the domestic cat (DC) to generate interspecific embryos by injecting cheetah (Ch) and leopard (Leo) spermatozoa. Firstly, DC oocytes were matured with insulin–transferrin–selenium (ITS) or without it (MM) and cultured using atmospheric (21%) or low (5%) oxygen tension after ICSI. The group ITS‐5%O₂ showed the highest blastocyst rate (p < 0.05), 20.9% vs 8.7%, 7% and 6.5%, for MM‐21%O₂, MM‐5%O₂ and ITS‐21%O₂, respectively. The best conditions were used to generate the interspecific embryos, together with ionomycin activation (Io) after ICSI. Interspecific embryos resulted in high rates of blastocysts that were not positively affected by Io activation: 32.6% vs 21% for Ch and Ch‐Io, 9.8% vs 21% for Leo and Leo‐Io, and 20% vs 17.4% for DC and DC‐Io. We also evaluated DNA‐fragmented nuclei of experiment 1 and 2 blastocysts, using TUNEL assay. The fragmented nucleus proportion was higher in the ITS‐5%O₂ group, 67.6%. Surprisingly, interspecific blastocysts showed the lowest fragmented nucleus proportion: 27% and 29.9% for Ch and Leo, respectively. We concluded that ITS and 5%O₂ improve blastocyst formation in DC, although with a concomitant increase in DNA fragmentation. Most importantly, cheetah and leopard spermatozoa were able to generate blastocysts without artificial activation, which suggests that developmental capacity of wild felid spermatozoa can be evaluated by interspecific ICSI. This technique should be used to assist wild felid reproduction.     

Effect of burning on the numbers of questing ticks collected by dragging

Sixteen experimental burn plot replicates, in groups of four, in four landscape zones of the Kruger National Park, South Africa, and from which wildlife are not excluded, have been subjected to fixed, regular burning regimens since 1954. In 1999, a study to determine the effect of burning on ixodid ticks questing for hosts from the vegetation of the plots was initiated, and six sub-plots, with identical histories, within each of two of the burn plot replicates in Combretum collinum/Combretum zeyheyri woodland on granite, were selected. With few exceptions these 12 sub-plots, as well as unburned vegetation adjacent to each of the replicates, were sampled for ticks at monthly intervals for a period of 39 months by dragging with flannel strips. The existing regimen of burning during August or during October on individual sub-plots was continued during this time. A total of 14 tick species was recovered from the plots of which nine could be considered major species. Sufficient numbers for statistical analysis of only eight species were, however, collected. Burning appeared to have little short-term effect on the number of ticks recovered. In the longer term, the response varied from no change, an increase, or a decrease in the numbers of ticks collected each year after burning. Tick species, life cycle, seasonality, questing strategy, host preference and host utilization of the habitat were important determinants of the effect of burning.     

Removal of Iron and Manganese from Water with a High Organic Carbon Loading. Part II: The Effect of Various Adsorbents and Nanofiltration Membranes

This paper describes the second part of an investigation into the removal of iron and manganese from water with a high dissolved organic carbon (DOC) loading. This investigation focused on the use of ferrichloride as coagulant in conjunction with hydrogen peroxide as an oxidant and different physical treatment processes, such as adsorption and nanofiltration, to reduce dissolved iron and manganese in water with a high DOC loading. It was found that nanofiltration employing H₂O₂ is the only treatment capable of producing drinking water within the set requirements of the treatment facility. Both fly ash and powdered activated carbon (PAC) used as adsorbents yielded a low percentage removal of DOC, while all the treatment methods evaluated accomplished high removals of the metallic ions Fe(II) and Mn(II). From the results a staggered treatment approach is recommended to obtain the best results at the lowest cost.     

污泥茶渣堆肥发酵过程酶活性变化

对污泥茶渣等物料进行堆肥发酵,结果表明:不同物料配比堆肥第3d均进入高温(75℃)降解阶段,持续时间16～18 d.污泥含量40％～50％处理的全氮、速效氮含量高于污泥含量30％的处理;处理D全氮含量最高,达19.17 g·kg-,各处理全氮平均值大小顺序为D＞E＞C＞B＞A;处理E速效氮含量最高,为1171mg·kg...     

Demonstration of colonies of Anaplasma marginale in the midgut of Rhipicephalus simus

Rhipicephalus simus nymphs were allowed to feed on a cow experimentally infected with the BW-strain of Anaplasma marginale from Republic of South Africa, and they were studied as adults. Colonies were demonstrated by light microscopy in midgut epithelial cells of adult ticks that were unfed (as adults), incubated, or prefed for 72 hours on a cow. The colonies occurred in 5 different morphologic types (1 to 5) that were similar to those described previously for a Virginia isolate of A marginale in Dermacentor andersoni. The colony density (number of colonies/0.001 mm2 midgut tissue examined) ranged from 0 to 2.0 and was highest in unfed ticks that were not incubated (mean 0.566). Colonies observed by light microscopy were sectioned for study with the electron microscope. The colonies contained both electron-dense forms and reticulated forms. The organisms in type 2 and 3 colonies appeared to be attached to one another, and those in type 4 and 5 colonies occurred separately. Small particles were seen within the limiting membrane of some organisms. A few colonies contained a dense matrix and were surrounded by many small electron-dense particles.     

Detection of shared magnetic antigenic determinants on whole Moraxella bovis pili by use of antisera to cyanogen bromide-cleaved M. bovis pilus protein

OBJECTIVE: To determine the ability of antisera against cyanogen bromide-cleaved pili from 4 strains of Moraxella bovis to react with whole or nondenatured pili. SAMPLE POPULATION: Antisera to 4 strains of M. bovis produced by New Zealand White rabbits. PROCEDURE: Pili from 4 strains of M. bovis were collected and purified. Pilus proteins (pilin) were cleaved, using cyanogen bromide. Whole pilus and cyanogen bromide-cleaved pilin were injected into rabbits. Antisera were serially diluted, reacted with 4 strains of M. bovis, and examined by immunoelectron microscopy and indirect immunofluorescence. RESULTS: Antisera to whole pili aggregated and distorted pili from homologous strains, but pili from heterologous strains were unaffected. Antisera to cleaved pilin fragments resulted in partial aggregation and thickening of homologous and heterologous pili, suggestive of heterospecific antibodies. Attachment of antibodies to pili was detected by indirect immunofluorescence, indicating a strong reaction of antisera to whole pili with homologous pili. Weak cross-reactions were evident with certain heterologous strains. In contrast, antisera to cleaved pilin fragments reacted strongly with pili from homologous and heterologous strains. CONCLUSIONS AND CLINICAL RELEVANCE: We detected shared antigenic determinants on pili from various strains of M. bovis that were not immunogenic in intact pili. These sites were immunogenic after cleavage of pilus protein with cyanogen bromide, and antisera produced to protein fragments reacted with whole pili from heterologous strains of the organism. Vaccines produced from cyanogen bromide-treated pili may induce broader immunity against infectious bovine keratoconjuctivitis than that provided by currently available vaccines.     

Ovine progressive pneumonia (Maedi-Visna): an emerging respiratory disease of sheep in Ethiopia

A serological study was done to assess the role of Maedi-Visna (MV) infection in sheep from flocks with high respiratory tract disease morbidity in Ethiopia. Of 105 sheep examined from central Ethiopia 78 (74%) were positive for MV-infection. However, antibodies to the virus were not detected in 48 sheep and 70 goats from elsewhere in Ethiopia. The infection was detected in all breeds of sheep examined (Awassi, Hampshire, Corriedale, indigenous Menz breeds and their crosses) but with a significant breed difference (chi 2 = 20, p < 0.001) varying from 48% in imported Awassi sheep to 92% in the indigenous Menz sheep. This suggests that Menz sheep are more susceptible to infection, which may support the observation of a higher incidence of clinical disease in these sheep compared to exotic breeds and their crosses. It also supports recent studies indicating that MV is becoming one of the most important respiratory tract diseases in sheep in central Ethiopia. Our findings indicate that MV was introduced into Ethiopia via sheep imported into the central highlands and that it now constitutes an important emerging disease is discussed. Measures to control the disease are suggested.     

Ultraslow electron spin dynamics in GaAs quantum wells probed by optically pumped NMR

Optically pumped nuclear magnetic resonance (OPNMR) measurements were performed in two different electron-doped multiple quantum well samples near the fractional quantum Hall effect ground state nu = 13. Below 0.5 kelvin, the spectra provide evidence that spin-reversed charged excitations of the nu = 13 ground state are localized over the NMR time scale of about 40 microseconds. Furthermore, by varying NMR pulse parameters, the electron spin temperature (as measured by the Knight shift) could be driven above the lattice temperature, which shows that the value of the electron spin-lattice relaxation time tau1s is between 100 microseconds and 500 milliseconds at nu = 13.