Hyperactivated Motility in Sperm   总被引：5，自引：0，他引：5  

SS Suarez  H-C Ho 《Reproduction in domestic animals》2003,38(2):119-124

Hyperactivation is a movement pattern seen in sperm at the site and time of fertilization in mammals. It may be critical to the success of fertilization, because it enhances the ability of sperm to detach from the wall of the oviduct, to move around in the labyrinthine lumen of the oviduct, to penetrate mucous substances and, finally, to penetrate the zona pellucida of the oocyte. The movement of hyperactivated sperm appears different under different physical conditions and in different species, but basically it involves an increase in flagellar bend amplitude and, usually, beat asymmetry. Presumably, a signal or signals exist in the oviduct to initiate hyperactivation at the appropriate time; however, none has yet been identified with certainty. While the signal transduction cascade regulating hyperactivation remains to be completely described, it is clear that calcium ions interact with the axoneme of the flagellum to switch on hyperactivation. Although hyperactivation often occurs during the process of capacitation, the two events are regulated by somewhat different pathways.  相似文献   

Implications of carbohydrate sources and rate of body weight gain on puberty in ewe lambs in tropical climate conditions     

Ferreira  Evandro Maia  de Castro Ferraz  Marcos Vinicius  Biava  Janaina Socoloviski  de Assis  Rhaíssa Garcia  Barroso  José Paulo Roman  Polizel  Daniel Montanher  de Araujo  Leandro Coelho  Pires  Alexandre Vaz 《Tropical animal health and production》2020,52(1):373-378

Tropical Animal Health and Production - The objectives were to evaluate the effects of two non-fibrous carbohydrate sources and the rate of body weight gain on puberty status in ewe lambs. Sixty...  相似文献   

Mycoplasma ovis in captive cervids: prevalence, molecular characterization and phylogeny     

Grazziotin AL  Santos AP  Guimaraes AM  Mohamed A  Cubas ZS  de Oliveira MJ  dos Santos LC  de Moraes W  Vieira RF  Donatti L  de Barros Filho IR  Biondo AW  Messick JB 《Veterinary microbiology》2011,152(3-4):415-419

Hemotrophic mycoplasmas (hemoplasmas) are bacteria that attach to red blood cells of mammals, leading to acute and/or subclinical disease in infected animals. It has been suggested that Mycoplasma ovis, a hemoplasma that infects sheep and goats worldwide, may also infect deer. The aim of this study was to evaluate whether South American deer are infected with M. ovis. EDTA-anticoagulated blood samples from a herd of 32 captive South American deer were collected. DNA extraction of blood samples was performed followed by PCR amplification of the 16S and 23S rRNA genes, and sequencing of products. Using M. ovis PCR, 27/31 (87%) were positive, including 21/22 Mazama nana; 2/3 Mazama americana and 4/6 Blastocerus dichotomus. Sequencing of the nearly entire 16S rRNA gene of 26/27 positive samples showed 98.2-98.8% identity to M. ovis of sheep (GenBank, AF338268) and 98.6-99.4% identity to M. ovis-like of a fawn (FJ824847); the 23S rRNA gene from one of these isolates and the fawn's had 97.6% identity. The remaining isolate had just 94.9% identity to the 16S rRNA gene of M. ovis and only 89.4% identity to the 23S rRNA gene of the fawn's M. ovis. This is the first report of M. ovis in captive South American deer, revealing a high prevalence of hemoplasma infection in these animals.  相似文献   

Large-Scale Synthesis of Aligned Carbon Nanotubes     

WZ Li  SS Xie  LX Qian  BH Chang  BS Zou  WY Zhou  RA Zhao  G Wang 《Science (New York, N.Y.)》1996,274(5293):1701-1703

Large-scale synthesis of aligned carbon nanotubes was achieved by using a method based on chemical vapor deposition catalyzed by iron nanoparticles embedded in mesoporous silica. Scanning electron microscope images show that the nanotubes are approximately perpendicular to the surface of the silica and form an aligned array of isolated tubes with spacings between the tubes of about 100 nanometers. The tubes are up to about 50 micrometers long and well graphitized. The growth direction of the nanotubes may be controlled by the pores from which the nanotubes grow.  相似文献   

Evaluation of soil extractants for silicon availability for sugarcane     

Carlos Alexandre Costa Crusciol  Dorival Pires de Arruda  Adalton Mazetti Fernandes  João Arthur Antonangelo  Luís Reynaldo Ferracciú Alleoni  Dirceu Maximino Fernandes 《Journal of plant nutrition》2013,36(17):2241-2255

Adequate evaluation and interpretation of silicon (Si) phytoavailability in soil is a key to fertilizer recommendation. This study was conducted to determine the effect of soil texture on the choice of Si extractant, and provide baseline data on the relationship between extractable Si and sugarcane Si accumulation. The effects of soil texture and extractant solutions of Si were investigated on soil of nine areas of sugarcane cultivation. Si contents in clayey soils were higher than in sandy soils only in the extraction with standard calcium chloride, acetic acid, potassium chloride (KCl), and sodium acetate buffer. Other extractants failed to reveal differences in the Si availability among the three soil textures. The choice of the extractant should consider soil texture for the determination of adequate Si contents in soils planted with sugarcane, and the extractants that proved to be more efficient in the three soil textures was acetic acid and KCl.  相似文献   

Priapism Associated with Lumbar Stenosis in a Dog     

R Payan‐Carreira  B Colaço  C Rocha  C Albuquerque  M Luis  H Abreu  MA Pires 《Reproduction in domestic animals》2013,48(4):e58-e64

Priapism, a persistent long‐lasting involuntary erection of the penis, is uncommon in dogs. In this report, the case of a 13‐year‐old male Pointer, referred to our services due to persistent exposition of the penis, is described. This condition was consecutive to an intermittent priapism situation lasting for several days, which has been initially attributed to the inflammation and haematoma associated with a perianal bite. The owners became unable to retract the penis into the prepuce. At presentation, the dog was anorectic for 48 h, intolerant to manipulation, and showed poor body condition and unsteady locomotion. During physical evaluation, a marked engorgement of the local vessels in the prepuce and penis was found. An abdominal X‐ray was asked under the suspicion of a neurogenic origin for the clinical situation, which showed evidences of spondylosis. After discussion of the clinical condition, the owners asked for euthanasia. The necropsy confirmed the engorgement of the regional vessels deriving from the pudendal arteries and blood accumulation within all the cavernous spaces, accompanied by congestion and thrombosis within the erectile structures of the penis. No significant changes were observed in the pelvic organs that could be at the origin of priapism. The lumbar‐sacral spinal regions were carefully inspected and evidenced signs of L7‐S1 stenosis due to spondylosis. The case presented herein is a rare situation of priapism of neurogenic origin in a dog. Necropsy findings suggest that it was consecutive to cauda equina compression due to lumbar spinal stenosis.  相似文献   

Expression and Localization of Vascular Endothelial Growth Factor and its Receptors in the Corpus Luteum During Oestrous Cycle in Water Buffaloes (Bubalus bubalis)     

VS Chouhan  RP Panda  VP Yadav  V Babitha  FA Khan  GK Das  M Gupta  SS Dangi  G Singh  S Bag  GT Sharma  B Berisha  D Schams  M Sarkar 《Reproduction in domestic animals》2013,48(5):810-818

The aim of this study was to document the expression and localization of VEGF system comprising of VEGF isoforms (VEGF 120, VEGF 164 and VEGF 188) and their receptors (VEGFR1 and VEGFR2) in buffalo corpus luteum (CL) obtained from different stages of the oestrous cycle. Real‐time RT‐PCR (qPCR), Western blot and immunohistochemistry were applied to investigate mRNA expression, protein expression and localization of examined factors. In general, all the components of VEGF system (the VEGF isoforms and their receptors) were found in the water buffalo CL during the oestrous cycle. The mRNA as well as protein expression of VEGF system was highest during the early and mid‐luteal phase, which later steadily decreased (p < 0.05) after day 10 to reach the lowest level in regressed CL. As demonstrated by immunohistochemistry, VEGF protein was localized predominantly in luteal cells; however, VEGFR1 and VEGFR2 were localized in luteal cells as well as in endothelial cells. In conclusion, the dynamics of expression and localization of VEGF system in buffalo corpora lutea during the luteal phase were demonstrated in this study, indicating the possible role of VEGF system in the regulation of luteal angiogenesis and proliferation of luteal as well as endothelial cells through their non‐angiogenic function.  相似文献   

Evaluation of Macroalgae Sulfated Polysaccharides on the Leishmania (L.) amazonensis Promastigote     

Camila Lehnhardt Pires  Selma Dzimidas Rodrigues  Daniel Bristot  Henrique Hessel Gaeta  Daniela de Oliveira Toyama  Wladimir Ronald Lobo Farias  Marcos Hikari Toyama 《Marine drugs》2013,11(3):934-943

The sulfated polysaccharides from Solieria filiformis (Sf), Botryocladia occidentalis (Bo), Caulerpa racemosa (Cr) and Gracilaria caudata (Gc) were extracted and extensively purified. These compounds were then subjected to in vitro assays to evaluate the inhibition of these polysaccharides on the growth of Leishmania (L.) amazonensis promastigotes. Under the same assay conditions, only three of the four sulfated polysaccharides were active against L. amazonensis, and the polysaccharide purified from Cr was the most potent (EC₅₀ value: 34.5 μg/mL). The polysaccharides derived from Bo and Sf demonstrated moderate anti-leishmanial activity (EC₅₀ values of 63.7 μg/mL and 137.4 μg/mL). In addition, we also performed in vitro cytotoxic assays toward peritoneal macrophages and J774 macrophages. For the in vitro cytotoxicity assay employing J774 cells, all of the sulfated polysaccharides decreased cell survival, with CC₅₀ values of 27.3 μg/mL, 49.3 μg/mL, 73.2 μg/mL, and 99.8 μg/mL for Bo, Cr, Gc, and Sf, respectively. However, none of the sulfated polysaccharides reduced the cell growth rate of the peritoneal macrophages. These results suggest that macroalgae contain compounds with various chemical properties that can control specific pathogens. According to our results, the assayed sulfated polysaccharides were able to modulate the growth rate and cell survival of Leishmania (L.) amazonensis promastigotes in in vitro assays, and these effects involved the interaction of the sulfated polysaccharides on the cell membrane of the parasites.  相似文献   

Complementary physical and chemical treatments as an alternative to fungicide use to control postharvest decay incidence and fruit quality of Montenegrina tangerines     

Cândida Raquel Scherrer Montero  Rose Beatriz Antes  Ligia Loss Schwarz  Liege Cunha dos Santos  Rinaldo Pires dos Santos  Renar João Bender 《Crop Protection》2010

Heat treatments affect the germination and development of pathogens and enhance the ability of fruits to resist infection after harvest. In the present work, the effects of heat, in combination with other alternative decay control methods, were studied on ‘Montenegrina’ tangerines along with the effects on the cuticular surface of the fruit. Different treatment combinations using hot water (60 °C), brushing, and immersion in chloride dioxide, imazalil, sodium bicarbonate, and hand-applied carnauba wax were used. The tangerines were then put in cold storage for 20 days at 5 °C and retrieved to ambient conditions for 7 more days. Fruit samples were analyzed for total soluble solids, titratable acidity, epidermal color, weight loss, and decay incidence; an analysis of fruit surface was done through scanning electron microscopy. Heat treatments significantly reduced the number of tangerines with decay symptoms and enhanced the efficacy of the tested products. Carnauba wax significantly increased the number of rotten fruits, exerting a protective effect on the fungi by covering their structure. Sodium bicarbonate in combination with heat exerted a good control on decay incidence. The heat treatments partially removed the hyphae and spores of pathogens on the surface and also melted the cuticular waxes that cover stomata and cracks, reducing possible entry points for pathogens.  相似文献   

The role of Cox-2 expression in the prognosis of dogs with malignant mammary tumours     

Felisbina L. Queiroga  Isabel Pires  Luís Lobo  Carlos S. Lopes 《Research in veterinary science》2010,88(3):441-445

Immunohistochemical detection of Cyclooxygenase (Cox)-1 and -2 enzymes in canine mammary tumours (CMT) has recently been described. However, the prognostic value of their expression needs to be established. The aim of this study was to investigate Cox (-1 and -2) prognostic value in malignant CMT by evaluating its correlation with clinicopathological parameters (tumour size, histological type, necrosis, lymph node metastasis) and with Disease Free Survival (DFS) and Overall Survival (OS). Twenty seven female dogs with malignant tumours were included. Cox-2 expression was associated with lymph node metastasis at surgery time, development of distant metastasis during follow-up (p = 0.038), DFS (p = 0.03) and OS (p = 0.04). Multivariate survival analysis showed that Cox-2 did not retain its significance as an independent prognostic factor. For Cox-1 expression, no statistically significant association was observed. Present study suggests the usefulness of testing Cox-2 specific inhibitors as part of an adjuvant therapy in female dogs with malignant mammary neoplasias.  相似文献