Fish species incidence patterns in naturally fragmented Chihuahuan Desert streams

We investigated how stream fragmentation affects local fish species persistence and extinction from three Rio Grande systems (Texas, USA) stream reaches with different levels of natural fragmentation. We examined species–volume (SV) relationships of fish assemblages in 42 pools across the watersheds and predicted greater fragmentation would correspond to an increase in the slope of the SV relationship due to decreased within‐reach rescue effects. In addition, we examined relationships among tributary‐specific nested subset patterns, local habitat features and spatial position of the reaches relative to the Rio Grande mainstem to better understand the importance of local and regional processes on fish species richness patterns in the stream reaches. Slopes of the SV curves did not differ among the stream reaches, but the intercepts of the SV curves were significantly different. These results indicated rescue effects among habitats within a stream reach were not apparent; however, rescue effects from the mainstem largely determined the species richness of a given stream reach. The nested subset patterns in all stream reaches were related to several local environmental factors, and large, deep pools provided important aquatic refugia in all three systems. We suggest declines in mainstem and tributary flows will likely continue to impact local and regional fish assemblage attributes. High flow events are important for dispersal and can reset tributary fish communities for the next extinction‐driven, successional cycle.     

Validation of the sperm quality analyzer and the hypo-osmotic swelling test for frozen-thawed ram and minke whale (Balaenoptera bonarensis) spermatozoa

The object of the present study was to investigate the validation of the sperm quality analyzer (SQA) and the hypo-osmotic swelling (HOS) test with standard sperm analysis methods in frozen-thawed ram and minke whale spermatozoa. In rams, highly significant correlations were observed in the percentage of motile spermatozoa (P<0.01) and sperm concentration (P<0.01) between the standard and SQA methods. But, the percentage of morphologically normal spermatozoa did not significantly correlate between the standard and SQA methods. The percentages of swollen spermatozoa at 15 minutes by the HOS test were significantly correlated with the motility by the standard (P<0.05) and by the SQA (P<0.05) methods. For minke whale spermatozoa, the SVI (sperm viability index) values by the standard method were significantly (P<0.001) correlated with the sperm motility index (SMI) values by SQA. The percentage of motile spermatozoa was also significantly correlated (P<0.01) with the motility measured by SQA. Using different hypo-osmotic solutions and incubation times, the HOS test with 25, 100 and 150 mOsM did not show significant variations. Motility observed by the standard method and the percentage of swollen spermatozoa were significantly correlated (P<0.05). These results indicate that the SQA and HOS test can be utilized to assess the post-thawing motility of ram and minke whale spermatozoa, and that the SQA and HOS test values are significantly correlated in ram spermatozoa. However, sperm concentration and morphologically normal spermatozoa are not assessed accurately by SQA in minke whales.     

Follicular development after ovum pick-up and fertilizability of retrieved oocytes in postpartum dairy cattle

This study aimed to evaluate gonadotropin secretion and the developmental competence of follicular oocytes in dairy cattle during the early postpartum (PP) period. The number of follicles developed after transvaginal ultrasound-guided ovum pick-up (OPU) and fertilizability of retrieved oocytes were compared between cows in which the first dominant follicle (DF) ovulated (ovulated group, n=4) and did not ovulate (non-ovulated group, n=3), and between early PP (early PP group, n=2) and after the resumption of the estrous cycle (cyclic group, n=2). Follicular ablation was performed 2-4 days after the detection of DF in the second follicular wave PP. OPU was repeated 3-5 times at 3 or 4-day intervals from 3-4 days after the follicular ablation. At OPU, the follicles were enumerated and all those > or = 5 mm in diameter were aspirated. Recovered oocytes were subjected to in vitro maturation and fertilization. Both criteria were similar between ovulated and non-ovulated groups, and between early PP and cyclic groups. These results suggest that FSH/LH secretions required for follicle recruitment and subsequent follicular growth during the early PP period are similar to those after resumption of the estrous cycle. They also indicate that follicular oocytes during the early PP period have developmental competence.     

Detection of Lawsonia intracellularis using immunomagnetic beads and ATP bioluminescence

Lawsonia intracellularis is an obligate intracellular pathogenic bacterium that causes proliferative enteropathy in various animals. The detection of L. intracellularis in clinical and environmental samples is necessary for the diagnosis of infection and epidemiological investigations. For the detection of L. intracellularis in fecal samples, we have developed an immunological method using immunomagnetic separation and ATP bioluminescence. Magnetic beads were coated with an anti-Lawsonia surface antigen (LsaA) antibody in order to capture the L. intracellularis in fecal samples from infected rabbits and the bacteria captured by the immunomagnetic beads were assayed by means of ATP bioluminescence. Our results showed that L. intracelluraris was detected by immunomagnetic separation of bacteria-holding magnetic beads and ATP-based bioluminescence, suggesting that our methods could be useful for the diagnosis of proliferative enteropathy.     

Evaluation of the inhibitory activities of the extracts of Indonesian traditional medicinal plants against Plasmodium falciparum and Babesia gibsoni

Twenty-four kinds of water extracts derived from 22 plants that are traditionally used for the treatment of malaria on Java Island, Indonesia, were screened for their antibabesial and antimalarial activities. Among the extracts, 8 extracts displayed strong antimalarial activity, with an inhibition range from 89.6 to 100%, and 15 showed strong antibabesial activity, with an inhibition range from 84.2 to 98.1%. The extracts of Achillea millefolium, Baeckea frutenscens, Brucea javanica, Curcuma xanthorrhiza, Strychnos lucida and Swietenia macrophylla showed both strong antibabesial and antimalarial activities. The antimalarial activities paralleled the antibabesial activities, but the converse was not true.     

利用RCR-RAPD法和同功酶分析法日本柳杉无性系的识别方法研究

以日本福岛县林业试验场日本柳杉种子园的 ２４个无性系为材料,利用 ＰＣＲ—ＲＡＰＤ法和同功酶分析法对日本柳杉无性系的识别方法进行了比较研究。结果显示：同功酶法和由７个标记构成的ＲＡＰＤ分析法不能完全识别２４个无性系,用１７个和２７个标记构成的ＲＡＰＤ分析法识别这２４个无性系是可能的;同功酶标记是一种基因型标记,具有稳定性高的特点,适合于分析遗传构造的相似程度,特别适合于群体遗传分析,但是,由于能获得清晰话带的同功酶种类有限,在用于个体识别上比较困难;ＲＡＰＤ标记是一种显性标记,稳定性较差,但只要反应体系和条件稳定,利用ＲＡＰＤ标记正确进行无性系识别是完全可能的。     

Pneumocystis Pneumonia in a Thoroughbred Racehorse

Pneumocystis pneumonia is an opportunistic respiratory infection that occurs in immunocompromised animals. In horses, pneumocystic pneumonia is observed mostly in foals and often progresses rapidly. Here, we report pneumocystic pneumonia in a Thoroughbred racehorse. A 3-year-old Thoroughbred racehorse colt had marked respiratory symptoms for 3 weeks and was unresponsive to antibiotic treatment. At necropsy, firm, tan, patchy lesions were scattered diffusely in the lungs. Microscopically, alveolar septa thickened by proliferation of collagen fibers and infiltration of inflammatory cells were observed. In the alveolar spaces, many brown-black yeast-like organisms similar to cystic forms of Pneumocystis carinii were recognized by staining with Gomori's methenamine silver. Bronchoalveolar lavage fluid (BALF) obtained before necropsy included macrophages engulfing the fungus bodies. Amplified products were obtained from BALF and lung tissue samples by Pneumocystis-specific nested PCR. Phylogenetic analysis based on the 18S rRNA gene sequence revealed that the P. carinii organism from BALF was related to the Pneumocystis spp. detected in other animals and was especially close to P. carinii derived from ferrets. This is a rare case of pneumocystic pneumonia in a colt with chronic pulmonary lesions.     

Osmolarity- and Stage-Dependent Effects of Glycine on Parthenogenetic Development of Pig Oocytes

The osmolarities of media that are most effective for in vitro culture of mammalian oocytes and embryos are lower than that of oviductal fluid. Oocytes and embryos can survive the high physiological osmolarity in vivo perhaps owing to the presence of amino acids such as glycine, which serve as organic osmolytes in the female reproductive tract. In the present study, the effects of glycine on the parthenogenetic development of pig oocytes were examined in hypotonic or isotonic media. The results showed that culturing oocytes in isotonic media improved the cleavage rates (P<0.01) at 2 days in culture but inhibited any further development beyond cleavage when compared with the hypotonic media. However, addition of 4 mM glycine to the isotonic media resulted in improved blastocyst formation rates compared with that observed in the hypotonic media (P<0.01), and there was no inhibition of development beyond the cleavage stages in oocytes. The beneficial effects of glycine were observed only when oocytes were cultured in isotonic media and glycine was added at day 2 or 3 in culture. The results from the present study indicate that an isotonic medium with glycine is useful for in vitro culture of pig oocytes and that glycine may protect pig oocytes against the detrimental effects of increased osmolarity.