Involvement of Ca2+-ATPase in suppressing the appearance of bovine helically motile spermatozoa with intense force prior to cryopreservation

In cattle, cryopreserved spermatozoa are generally used for artificial insemination (AI). Many of these specimens exhibit helical movement, although the molecular mechanisms underlying this phenomenon remain unclear. This study aimed to characterize helically motile spermatozoa, investigate the involvement of Ca²⁺-ATPase in suppressing the appearance of these spermatozoa prior to cryopreservation, and examine the potential of helical movement as an index of sperm quality. In the cryopreserved semen, approximately 50% of spermatozoa were helically motile, whereas approximately 25% were planarly motile. The helically motile samples swam significantly faster than those with planar movement, in both non-viscous medium and viscous medium containing polyvinylpyrrolidone. In contrast, in non-cryopreserved semen, planarly motile spermatozoa outnumbered those that were helically motile. Fluorescence microscopy with Fluo-3/AM and propidium iodide showed that flagellar [Ca²⁺]_i was significantly higher in cryopreserved live spermatozoa than in non-cryopreserved live ones. The percentage of non-cryopreserved helically motile spermatozoa was approximately 25% after washing, and this increased significantly to approximately 50% after treatment with an inhibitor of sarcoplasmic reticulum Ca²⁺-ATPases (SERCAs), “thapsigargin.” Immunostaining showed the presence of SERCAs in sperm necks. Additionally, the percentages of cryopreserved helically motile spermatozoa showed large inter-bull differences and a significantly positive correlation with post-AI conception rates, indicating that helical movement has the potential to serve as a predictor of the fertilizing ability of these spermatozoa. These results suggest that SERCAs in the neck suppress the cytoplasmic Ca²⁺-dependent appearance of helically motile spermatozoa with intense force in semen prior to cryopreservation.     

猪精液4℃低温保存技术研究

为丰富猪鲜精保存技术、改善与提高精液保存质量,本研究以市场占有率高、性能稳定和可耐受4℃低温的长效稀释剂为对照,探讨本课题组研制的4℃稀释剂(低温Ⅰ号、低温Ⅱ号)对猪精液低温保存效果的影响。结果表明:低温Ⅰ号和低温Ⅱ号稀释剂对猪精液的有效保存时间和总存活时间均显著高于对照组(P<0.05)。保存至第6天时,对照组精子活力显著降低(P<0.05),保存至第10天时,低温Ⅰ号、低温Ⅱ号、对照组精子活力分别为74.6、76.0、0;保存第10天时,对照组pH显著低于2个实验组(P<0.05);保存从第5天开始,实验组质膜完整性显著高于对照组(P<0.05)。综上,本课题组研制的稀释剂对猪精液4℃低温保存效果较好,而且低温Ⅱ号对精子活力和质膜完整性保存效果更优。     

不同品种公猪精液品质调查

为了研究品种不同的种公猪的精液品质之间存在的差异,本试验通过对长白、大白、杜洛克等3个品种的成年种公猪的精液品质进行统计学方法分析和比较。结果显示:长白公猪的精子活率最好(75.03%),然后依次是大白(71.62%)、杜洛克(70.36%),长白与大白及杜洛克之间差异显著(P<0.05),但大白与杜洛克之间差异不显著(P>0.05);长白种公猪的精液量(337.60mL)与大白(380.00mL)之间差异不显著(P>0.05),但均与杜洛克(251.74mL)之间差异显著(P<0.05)。三个品种精子活率由高到低依次为长白、大白、杜洛克;平均精液量大小依次为大白、长白、杜洛克,综合评价,长白猪的精液品质最好。     

Effects of drought on isolates of <Emphasis Type="Italic">Bradyrhizobium elkanii</Emphasis> cultured from <Emphasis Type="Italic">Albizia adianthifolia</Emphasis> seedlings of different provenances

Albizia adianthifolia (Schumach) W. F. Wright, a N-fixing legume tree, has a wide distribution in Africa, in Ghana occurring in high rainfall forests and in seasonally droughted forests, and is associated in the Ghanaian forest zone with dry, infertile sites. We hypothesised that A. adianthifolia hosted different rhizobial strains in different forest types, and that these different strains would show different growth responses to moisture stress and different motility and mortality in droughted soil. Three isolates, extracted from seedlings of A. adianthifolia growing in three forest types differing in seasonal drought, were identified as Bradyrhizobium elkanii and exposed to varying levels of osmotic stress. Growth responses varied between the three strains, one of which displayed clear signs of drought tolerance. A novel approach using soil leaching columns was used to test the effects of soil pore water (in terms of neck diameter) on both the survival and movement of wet and dry forest rhizobial isolates through soil columns. The responses of the isolates were significantly different, the pore neck diameter, marginally insignificant and the drought treatment insignificant. Thus the dry forest isolate survived better in all treatments, and showed less response to the treatments, than the isolate from the wet forest. The results offer preliminary evidence that Bradyrhizobium elkanii strains from A. adianthifolia in Ghana have evolved in response to local differences in seasonal water availability. These differences could assist the selection of A. adianthifolia provenances for agroforestry or land rehabilitation.     

Esophageal dysmotility in young dogs

BACKGROUND: Abnormal esophageal motility can exist without megaesophagus, although its prevalence in dogs is unknown and its cause has not been elucidated. HYPOTHESIS: Esophageal dysmotility without overt megaesophagus exists in both symptomatic and asymptomatic young dogs, and motility can improve with age. ANIMALS: Dogs examined at the Department of Veterinary Medicine, University of Cambridge for regurgitation, but without evidence of megaesophagus on radiographs, and a further group of asymptomatic dogs. METHODS: Dogs underwent an initial and a repeat videofluoroscopic swallowing study. Images were reviewed and 5 criteria of esophageal motility evaluated. RESULTS: Eight affected dogs were identified (median age 9 months), and terrier dogs predominated (6 terriers of 3 breeds). Esophageal motility was reduced either globally (n = 3) or segmentally (n = 5). Repeat examination at a median of 3 months revealed that regurgitation had reduced or resolved in the majority of terrier dogs, and 4 of 6 cases demonstrated an improvement in esophageal motility. Videofluoroscopic evaluation of young (median age 11 months) asymptomatic dogs of various breeds (n = 22) revealed evidence of esophageal dysmotility in 4 of 5 control terrier dogs. Repeat evaluation demonstrated an improvement in esophageal motility in 3 dogs. CONCLUSION AND CLINICAL IMPORTANCE: Esophageal dysmotility without overt megaesophagus occurs in young terrier dogs, and affected animals can be symptomatic or asymptomatic. Further, an improvement in esophageal motility occurs with time in some dogs, and might represent a syndrome of delayed esophageal maturation.     

Expression and function of 5-HT7 receptors in smooth muscle preparations from equine duodenum, ileum, and pelvic flexure

In horses, gastrointestinal (GI) disorders occur frequently and cause a considerable demand for efficient medication. 5-Hydroxytryptamine receptors (5-HT) have been reported to be involved in GI tract motility and thus, are potential targets for treating functional bowel disorders. Our studies extend current knowledge on the 5-HT₇ receptor in equine duodenum, ileum and pelvic flexure by studying its expression throughout the intestine and its role in modulating contractility in vitro by immunofluorescence and organ bath experiments, respectively.5-HT₇ immunoreactivity was demonstrated in both smooth muscle layers, particularly in the circular one, and within the myenteric plexus. Interstitial cells of Cajal (ICC), identified by c-Kit labeling, show a staining pattern similar to that of 5-HT₇ immunoreactivity.The selective 5-HT₇ receptor antagonist SB-269970 increased the amplitude of contractions in spontaneous contracting specimens of the ileum and in electrical field-stimulated specimens of the pelvic flexure concentration-dependently.Our in vitro experiments suggest an involvement of the 5-HT₇ receptor subtype in contractility of equine intestine. While the 5-HT₇ receptor has been established to be constitutively active and inhibits smooth muscle contractility, our experiments demonstrate an increase in contractility by the 5-HT₇ receptor ligand SB-269970, suggesting it exerting inverse agonist properties.     

不同铵离子浓度与pH人工海水对栉江瑶精子激活效果的比较

栉江瑶(Atrina pectinata)为我国重要的海洋经济双壳贝类,近年来,其养殖生产活动备受养殖企业关注,为发展和优化其人工繁殖技术,本研究探究了人工海水中铵离子浓度和pH的变化对栉江瑶新鲜精子游泳运动的激活作用,定量描述了高度活化状态下精子曲线运动速率(VCL)、直线运动速率(VSL)、平均路径运动速率(VAP)和鞭毛摆动频率(BCF)的运动学特征,并对精子ATP含量、ATP酶与超氧化物歧化酶(SOD)活性进行了记录。结果显示,简单提高海水pH可略微提高栉江瑶精子运动率,但无法使精子进入高度活化状态;含有铵离子的碱化海水可有效激发精子游泳运动,3 mmol/L氨海水激活效果最佳。经3 mmol/L氨海水激活后,精子活力等级(MI)在21 min内一直保持在≥4的状态,在激活的前3 min内精子运动率都在80%以上,VCL>56 μm/s,VSL>17 μm/s,VAP>30 μm/s,BCF>6 Hz。精子ATP含量在激活5 min后降低至初始含量的30.29% [(128.80± 66.92) μmol/g prot],随后,无显著变化(P>0.05)。精子Na+-K+-ATP酶和Ca2+-Mg2+-ATP酶活性在运动过程中较为稳定,其中,Na+-K+-ATP酶活性较低[(0.62±0.03) U/mg prot],Ca2+-Mg2+-ATP酶活性较高[(6.08± 0.04) U/mg prot]。精子SOD活性在15 min内逐步降低至[(1.23±0.73) U/mg prot],随后维持稳定。本研究可为栉江瑶精子激活机制深入研究提供基础,助力发展栉江瑶人工繁育技术。     

Sugar transporter (MfsX) of the major facilitator superfamily is required for flagella-mediated pathogenesis in <Emphasis Type="Italic">Dickeya dadantii</Emphasis> 3937

Dickeya dadantii (syn. Erwinia chrysanthemi) is a causal agent of soft-rot diseases on many crops. Here, we characterized a gene belonging to the major facilitator superfamily (MFS), which is involved in the symport, antiport, or uniport of various substrates, and the survival and virulence of many Gram-negative bacterial animal pathogens, for the possible involvement in the plant pathogenicity of D. dadantii. A marker-exchange mutant of this gene (mfsX) was constructed that had decreased maceration ability in Chinese cabbage, potato, and chicory. Observation with electron microscopy showed greatly reduced numbers of flagella per cell. This mutant had a significant reduction in swimming and swarming motility and a severe reduction in formation of biofilm. Because these phenotypes have been shown to be involved in plant pathogenicity of D. dadantii, mfsX seems to play an important role in pathogenesis of D. dadantii 3937 by its involvement in the expression of these pathogenicity-related phenotypes.     

Pentoxifylline induces capacitation and acrosome reaction and improves quality of motility in canine ejaculated spermatozoa

To evaluate effects of different concentrations of pentoxifylline, as phosphodiesterase inhibitor, on quality of motility, capacitation and acrosome reaction, Ejaculated spermatozoa were collected from crossbred dogs. The sperm were incubated at concentrations of 0.1, 1, 10 and 100 mM pentoxifylline for 2 h. Conventional assessment was also made on the percentage of motility and quality of motility of spermatozoa; values were expressed as sperm motility index (SMI). Capacitation and acrosome reaction were also evaluated by chlortetracycline fluorescence staining. SMI as quality index of sperm was significantly increased in concentrations of 10 and 100 mM pentoxifylline during 1 and 2 h compared to control. The number of capacitated or acrosome reacted spermatozoa significantly (P < 0.05) were higher than controls at high concentrations of pentoxifylline (10 and 100 mM) during 1 and 2 h. In conclusion, high concentration of pentoxifylline is able to induce capacitation and acrosome reaction and improves quality of motility in canine ejaculated spermatozoa.