一种醇类雄性不育剂对高原鼠兔精子的影响

高原鼠兔(Ochotona curzoniae),隶属于兔形目(Lagomorpha),鼠兔科(Ochotonidae),又名黑唇鼠兔,主要分布于青藏高原及其边缘地带,栖息于海拔4 000 m左右的宽谷草原草甸区(王酉之和胡锦矗,1999),在食物链中扮演着重要的角色,是青藏高原草原生态系统中的关键物种.近年来随着全球变暖、若尔盖湿地水位下降等因素,高原鼠兔在若尔盖湿地繁殖加快,高原鼠兔成了危害草原生态系统的主要害兽(刘少英,2005).1997年,若尔盖湿地高原鼠兔平均种群密度为6 400只/km2(刘少英和冉江洪,1999),据我们2007年的调查显示,平均种群数量上升到25 000只/km2,控制鼠兔数量迫在眉睫.     

Ultra-acute exposure to cadmium does not impair whitefish sperm motility

Cadmium (Cd) exposure can impair the traits of aquatic animals associated with reproduction. In natural lakes Cd is typically detected at concentrations below 0.001 mg l⁻¹. The authors investigated the impact of ultra-acute Cd exposure on sperm motility in European whitefish (Coregonus lavaretus). They activated sperm with water containing various nominal concentrations of Cd and recorded sperm motility parameters. Only the highest Cd concentration (500 mg l⁻¹) was associated with decreased sperm swimming velocity and increases in both the percentage of static cells and curvature of the sperm swimming trajectory. The results indicate that environmentally realistic concentrations of Cd during the sperm motility activation are not critically harmful to male C. lavaretus fertilization potential.     

Environmental osmolality influences sperm motility activation in an anuran amphibian

Evolutionary theory predicts that selection will favour sperm traits that maximize fertilization success in local fertilization environments. In externally fertilizing species, osmolality of the fertilization medium is known to play a critical role in activating sperm motility, but there remains limited evidence for adaptive responses to local osmotic environments. In this study, we used a split‐sample experimental design and computer‐assisted sperm analysis to (i) determine the optimal medium osmolality for sperm activation (% sperm motility and sperm velocity) in male common eastern froglets (Crinia signifera), (ii) test for among‐population variation in percentage sperm motility and sperm velocity at various activation‐medium osmolalities and (iii) test for among‐population covariation between sperm performance and environmental osmolality. Frogs were obtained from nine populations that differed in environmental osmolality, and sperm samples of males from different populations were subjected to a range of activation‐medium osmolalities. Percentage sperm motility was optimal between 10 and 50 mOsm kg^?1, and sperm velocity was optimal between 10 and 100 mOsm kg^?1, indicating that C. signifera has evolved sperm that can function across a broad range of osmolalities. As predicted, there was significant among‐population variation in sperm performance. Furthermore, there was a significant interaction between activation‐medium osmolality and environmental osmolality, indicating that frogs from populations with higher environmental osmolality produced sperm that performed better at higher osmolalities in vitro. This finding may reflect phenotypic plasticity in sperm functioning, or genetic divergence resulting from spatial variation in the strength of directional selection. Both of these explanations are consistent with evolutionary theory, providing some of the first empirical evidence that local osmotic environments can favour adaptive sperm motility responses in species that use an external mode of fertilization.     

Comparison of sperm velocity, motility and fertilizing ability between firstly and secondly activated spermatozoa of common carp (Cyprinus carpio)

The objective of the study was to compare carp sperm motility performances (sperm velocity and motility rates) from 10 males including fertilizing ability (hatching rates from 10 males and eight females) as a function of time elapsed after sperm exposure to activation medium in two situations: firstly activated sperm and sperm which had terminated swimming and was ‘re‐activated’ after incubation in a K⁺ rich (200 mm KCl) non‐swimming solution. In case of both initial (first) and secondly activated spermatozoa, the motility was triggered in hatchery solution (HAS, 11.2 mOsmol) and in carp activation solution (CAS, 128.9 mOsmol) containing 45 mm NaCl, 5 mm KCl, 30 mm Tris–HCl while also adjusted to a pH of 8.0. First time activated sperm showed significantly higher relative motility, sperm velocity and fertilizing ability compared to re‐activated sperm. The carp spermatozoa (in either first or second activation) rapidly lost their fertilizing ability as a function of exposure time of sperm to diluents prior to addition to eggs: this shows that spermatozoa must be in contact with eggs as soon as their motility is triggered. When sperm was firstly activated in CAS and also activated a second time in CAS (labeled CASCAS) the hatching rate was significantly higher at egg contact after 10, 20, 30, and 120 s of activation. Also at 20 s after the second activation of the sperm higher sperm motility was observed compared to the first activation. This study showed that incubation of spermatozoa in a K⁺‐rich incubation medium can mitigate the affects of structural damages occurring in re‐activated sperm, which may help spermatozoa to increase their motility and fertilization. To our knowledge, the results presented in this study document for the first time that fertilization can be achieved with sperm re‐activated a second time while being exposed to a incubation medium that permits ATP reloading within the flagellum. Previous studies have show the potential for recovery of motility, however, the effect on possible fertilization is hitherto unknown. It critical outcome of the study clearly indicated the need for avoiding the use of different, subsequent activation media (e.g. first and second activation) but only on the same medium for both steps (see above CASCAS).     

中缅树鼩精子形态特征及冷冻损伤

树鼩作为一种新型的、接近灵长类的实验动物,在医学生物学上的应用受到越来越多的重视。精子的结构特性研究及冷冻后结构的完整性分析是精子生物学的主要内容,也有助于树鼩的实验室快速繁殖。该研究采用人工饲养的中缅树鼩(Tupaia belangeri chinensis),结果显示其睾丸占总体重的(1.05±0.07)%,总体积为(1.12±0.10)mL。附睾尾及输精管精子总量估计在2.2×107～8.8×107,其运动度和顶体完整率分别为(68.8±3.9)%和(90.0±2.1)%。利用扫描电子显微镜和透射电子显微镜对树鼩附睾精子的超微结构进行的观察和分析显示精子头部呈圆形或卵圆形;头部长度、宽度平均分别为6.65和5.82μm;精子尾部中段、主段、尾段和精子总长度平均分别为13.39、52.35、65.74和73.05μm;尾部中段的线粒体螺旋数量为48个,其轴丝结构为典型的"9+9+2"结构。冷冻解冻后的精子主要表现在顶体与质膜不完整、精子断裂、尾部扭曲和膨大。上述结果提示树鼩精子与其他哺乳动物精子的结构特征相似,但是精子大小和线粒体螺旋数目有明显的差别,且超微结构改变仍是冷冻精子运动和受精能力下降的主要原因。     

Protective effects of propolis on cryopreservation of common carp (Cyprinus carpio) sperm

Cryopreservation of sperm is common procedures in aquaculture, particularly used for routine in artificial insemination. However, these application cause damages and adversely affected sperm motility, viability and consequently lower hatching rates. The objective of this study is to determine whether propolis has an effect on cryopreservation and fertilization ability and to investigate the potential protective effect of propolis on spermatozoa of Cyprinus carpio. Many studies have been done in cryopreservation offish spermatozoa, but none of them contain propolis in extender composition. The extenders were prepared by using modified Kurokura Solution to which 10% Me₂SO added with different levels of propolis (0.2, 0.4, 0.6, 0.8 and 1 mg ml⁻¹) and 10% egg yolk (as a control without propolis). The pooled semen samples diluted at the ratio of 1:9 by the extenders were subjected to cryopreservation. The percentage and duration of motility and fertilization tests of cryopreserved sperm samples have been done immediately after thawing and compared with control and fresh semen. The extenders containing propolis exhibited higher percentage motility and motility duration than control group (P < 0.05). Especially the group IV (0.8 mg ml⁻¹ propolis) and the group V (1 mg ml⁻¹ propolis) showed significant positive effects on both post thaw motility and hatching ability. The propolis maintained the integrity of the spermatozoa during the cryopreservation process. Evaluating with its contents, it has been shown that propolis is an appropriate cryoprotective agent in fish semen.     

Cryopreservation of epididymal sperm in tree shrews (Tupaia belangeri)

Cryopreservation of sperm from tree shrews, which are considered primitive primates, would enhance genetic management and breeding programs. Epididymal sperm were surgically harvested from male tree shrews, cryopreserved in two Tes-Tris-based cryodiluents, and used in four experiments. In Experiment 1, there were no significant differences in motility and acrosome integrity among five concentrations of egg yolk in TTE after cooling to 4 °C. However, sperm frozen in TTE containing 20% egg yolk at −172 °C/min had better (P < 0.05) post-thaw motility and acrosome integrity. In Experiment 2, sperm held for 10 min prior to storage in liquid nitrogen had greater motility than those held for 5 or 15 min (P < 0.05), but acrosome integrity was not different (P > 0.05) among treatments. In Experiment 3, sperm frozen in TTE diluent had higher (P < 0.05) motility and acrosome integrity than those in TEST diluent. In Experiment 4, there were no differences (P > 0.05) in the fertilization rate of oocytes and the proportion of tree shrews yielding fertilized oocytes, following AI with fresh versus frozen sperm. In conclusion, tree shrew epididymal sperm were successfully cryopreserved, as assessed by post-thaw motility, acrosome integrity, and fertilizing ability.     

Zebrafish reproduction: revisiting in vitro fertilization to increase sperm cryopreservation success

Although conventional cryopreservation is a proven method for long-term, safe storage of genetic material, protocols used by the zebrafish community are not standardized and yield inconsistent results, thereby putting the security of many genotypes in individual laboratories and stock centers at risk. An important challenge for a successful zebrafish sperm cryopreservation program is the large variability in the post-thaw in vitro fertilization success (0 to 80%). But how much of this variability was due to the reproductive traits of the in vitro fertilization process, and not due to the cryopreservation process? These experiments only assessed the in vitro process with fresh sperm, but yielded the basic metrics needed for successful in vitro fertilization using cryopreserved sperm, as well. We analyzed the reproductive traits for zebrafish males with a strict body condition range. It did not correlate with sperm volume, or motility (P>0.05), but it did correlate with sperm concentration. Younger males produced more concentrated sperm (P<0.05). To minimize the wastage of sperm during the in vitro fertilization process, 10⁶ cells/ml was the minimum sperm concentration needed to achieve an in vitro fertilization success of ≥ 70%. During the in vitro process, pooling sperm did not reduce fertilization success (P>0.05), but pooling eggs reduced it by approximately 30 to 50% (P<0.05). This reduction in fertilization success was due not to the pooling of the females'' eggs, but to the type of tools used to handle the eggs. Recommendations to enhance the in vitro process for zebrafish include: 1) using males of a body condition closer to 1.5 for maximal sperm concentration; 2) minimizing sperm wastage by using a working sperm concentration of 10⁶ motile cells/ml for in vitro fertilization; and 3) never using metal or sharp-edged tools to handle eggs prior to fertilization.     

Management of pikeperch Sander lucioperca (Linnaeus, 1758) sperm quality after stripping

The aim of this study was to identify the potential for optimizing management of sperm quality during commercial reproduction of pikeperch Sander lucioperca. Sperm from different males is often pooled prior to fertilization or stored for short periods (hr) until ovulated eggs become available. A novel approach was applied to assess pooling effects by cross‐wise transfusion of sperm and seminal fluid (SF) of males with differing initial sperm quality. In addition, the effects of two different buffers (glucose and KCl) were tested, as well as a supplementation of melatonin and progesterone (1 mmol L^?1) to maintain or improve the quality of freshly stripped and incubated (0.5, 1, 2, 4 and 24 hr) sperm. Sperm motility and curvilinear velocity (VCL) were measured by computer assisted sperm analysis (CASA). The VCL proved to be a more sensitive, reliable parameter compared to motility, since significant differences occurred up to 3.5 hr earlier. Transfusion of SF between low and high quality sperm resulted in a significant decrease in sperm with high initial VCL (seven out of 22 transfusions), whereas VCL of low quality sperm could not be improved. In only one case did a transfusion result in an increased VCL. No treatment prevented a significant quality loss over 24 hr or even enhanced sperm performance. Conclusively, pooling sperm of different qualities as well as short‐term storage has a significant, negative impact on overall sperm quality. Pooling should only be considered when the sperm quality is known.     

Assessing the Validity of Body Mass Index Standards in Early Postmenopausal Women

Objective: To examine the relationship between percentage of total body fat (%Fat) and body mass index (BMI) in early postmenopausal women and to evaluate the validity of the BMI standards for obesity established by the NIH. Research Methods and Procedures: Three hundred seventeen healthy, sedentary, postmenopausal women (ages, 40 to 66 years; BMI, 18 to 35 kg/m²; 3 to 10 years postmenopausal) participated in the study. Height, weight, BMI, and %Fat, as assessed by DXA, were measured. Receiver operating characteristic analysis was performed to evaluate the ability of BMI to discriminate obesity from non‐obesity using 38%Fat as the criterion value. Results: A moderately high relationship was observed between BMI and %Fat (r = 0.81; y = 1.41x + 2.65) with a SE of estimate of 3.9%. Eighty‐one percent of other studies examined fell within 1 SE of estimate as derived from our study. Receiver operating characteristic analysis showed that BMI is a good diagnostic test for obesity. The cutoff for BMI corresponding to the criterion value of 38%Fat that maximized the sum of the sensitivity and specificity was 24.9 kg/m². The true‐positive (sensitivity) and false‐positive (1 ? specificity) rates were 84.4% and 14.6%, respectively. The area under the curve estimate for BMI was 0.914. Discussion: There is a strong association between %Fat and BMI in postmenopausal women. Current NIH BMI‐based classifications for obesity may be misleading based on currently proposed %Fat standards. BMI >25 kg/m² rather than BMI >30 kg/m² may be superior for diagnosing obesity in postmenopausal women.     

Effect of osmotic immobilization on refrigerated storage and cryopreservation of sperm from a viviparous fish, the green swordtail Xiphophorus helleri

In this study, refrigerated storage and cryopreservation of sperm from the green swordtail Xiphophorus helleri were investigated. Previous cryopreservation research in this species utilized motile sperm because unlike in most fish species, Xiphophorus sperm can remain continuously motile after collection for a week with refrigerated storage. However, this species reproduces by internal fertilization, and given the significant requirements for motility within the female reproductive tract and potential limitations on sperm energetic capacities, immobilization of sperm prior to insemination could be used to improve fertilization success. Thus, the goal in this study was to use osmotic pressure to inhibit the motility of sperm after collection from X. helleri, and to test the effect of immobilization on refrigerated storage and cryopreservation. The objectives were to: (1) estimate the motility of sperm at different osmotic pressures, and determine an osmotic pressure suitable for immobilization; (2) cryopreserve the immobilized sperm, and estimate the motility after thawing with or without dilution, and (3) compare motility of non-immobilized and immobilized sperm after thawing, centrifugation, and washing to remove cryoprotectant. Motility was determined when sperm were suspended in 11 different osmotic pressures (24-500 mOsmol/kg) of Hanks' balanced salt solution (HBSS). Motility was observed between 116 and 425 mOsmol/kg. Sperm were not motile when the osmolality was lower than 116 or higher than 425 mOsmol/kg. Motility of the immobilized (non-motile) sperm could be activated by changing the osmotic pressure to 291-316 mOsmol/kg, and motility of immobilized sperm from hypertonic HBSS (425 mOsmol/kg) was significantly higher than that from hypotonic HBSS (145 mOsmol/kg) after 48 h of storage. At an osmolality of 500 mOsmol/kg, HBSS was used as extender to maintain immobilized sperm during cryopreservation with glycerol as the cryoprotectant. High motility (approximately 55%) was obtained in sperm after thawing when cryopreserved with 10-15% glycerol, and dilution of thawed sperm in fresh HBSS (1:4; V:V) was found to decrease the motility significantly. No difference was found in the motility of thawed sperm cryopreserved with 14% glycerol and extended in 310 and 500 mOsmol/kg HBSS. Washing by centrifugation prolonged the motility of thawed sperm from 24 to 72 h in HBSS at 310 and 500 mOsmol/kg. This study showed that sperm from X. helleri could be immobilized by use of specific osmotic pressures, and that the immobilization did not affect sperm motility after thawing. The immobilization of sperm by osmotic pressure could minimize reduction of the energetic capacities necessary for insemination, traversal, and residence within the female reproductive tract, and fertilization.     

Pseudoephedrine induces sperm abnormalities, lower sperm counts and increased apoptosis in rat testis

Pseudoephedrine, an over-the-counter drug, is commonly used for the treatments of asthma, nasal congestion, and obesity. Furthermore, it can be used as a psychostimulant drug if taken in large doses; however, there have been no reports on its effects on reproduction. The aim of this study was therefore to investigate the effects of pseudoephedrine administration on sperm morphology, sperm concentration and apoptotic activity in the rat testis. Rats were administered intraperitoneally (IP) with pseudoephedrine at 120?mg/kg for the acute group and 80?mg/kg, IP, once daily for 15?days for the chronic group, while a control group was treated with vehicle. The percentages of normal sperm morphology were significantly decreased in both acute and chronic groups when compared with controls while the total sperm count was significantly decreased in the acute group. Apoptotic activities were increased significantly in both pseudoephedrine-treated groups. The results indicate that pseudoephedrine can induce sperm abnormalities, decrease sperm numbers and increase apoptotic activity in the testis of rats if taken at high doses. The results of this study suggest that the users of pseudoephedrine in medical treatments need to be aware of its potential toxicity involving spermatogenesis.     

Obesity in Families of Extremely Obese Women

In order to assess the prevalence of obesity in families of extremely obese individuals, we conducted a mail survey of a national obesity organization. Thirty-nine percent (N=981) of the questionnaires were completed and returned. Respondents were excluded from further analysis if they were adopted, male, their gender could not be determined, provided incomplete information about their parents or their own height and weight, or were less than 22 or greater than 63 years of age. The analyses included 729 probands and their families. Both the prevalence and the extent of obesity were high in the families members. The average family members' body mass index (BMI=kg/m² was 30, and 78% of the families studied had at least one other obese (BM1>30 kg/m²) first-degree relative (parent, sibling, or child). Although obesity was common in the families, survey respondents were generally the heaviest members of their families, having an average BMI of 47 kg/m². Correlations among first- degree relatives were similar to those found for average weight groups, suggesting that obesity and BMI are similarly influenced by family genetic factors in this extremely obese population.     

Correcting biases in estimates of mortality attributable to obesity

Objective: To assess whether a recent study that found a relatively small number of excess deaths attributable to obesity may have underestimated by not correcting for statistical biases. Research Methods and Procedures: This prospective cohort study used data from the First National Health and Nutrition Examination Survey Epidemiologic Follow‐Up Study. Survival analyses were conducted using 9690 individuals 32 to 87 years of age and 1886 all‐cause deaths during a 9.1‐year follow‐up. Corrections were made for the reputed regression‐dilution bias by using the average BMI during the decade before follow‐up as predictor. Corrections for the reputed reverse‐causation bias were made by excluding participants with a history of serious illness. Attributable fractions were calculated and used to estimate excess deaths. Results: The uncorrected estimate of excess deaths attributable to obesity (BMI ≥30) was 41.9, using 18.5 to 25 kg/m² as ideal‐weight category. Using average BMI as predictor increased the estimate to 93.3. Correcting for reverse‐causation effects increased the estimate further to 131.1 (range, 93.3 to 169.0). The uncorrected hazard ratio, 1.25, was increased to 1.41 by using average BMI as predictor, and then to 2.40 by correcting for reverse causation. Using BMI 21 to 25 kg/m² and 23 to 25 kg/m² as ideal‐weight categories increased the corrected estimates to 144.6 (range, 80.5 to 177.2) and 164.1 (range, 103.8 to 194.9), respectively. Larger increases were found for overweight and Grade 2 to 4 obesity (BMI ≥35 kg/m²). For overweight, the uncorrected estimate using 18.5 to 25 kg/m² as ideal‐weight category was ?88.3 and the corrected estimate using 23 to 25 kg/m² as ideal‐weight category was 205.4 (range, 114.5 to 296.3). Discussion: Correcting for statistical biases and using higher ideal‐weight categories increased the estimate of excess deaths attributable to obesity by ～400% and changed the negative estimate for overweight to a large positive estimate.     

Modeling the Impact of Adjustable Gastric Banding on Survival in Patients with Morbid Obesity

Objective: Morbid obesity is associated with premature death. Adjustable gastric banding may lead to substantial weight loss in patients with morbid obesity. Little is known about the impact of weight loss on survival after adjustable gastric banding. We therefore developed a mathematical model to estimate life expectancy in patients with a body mass index (BMI) ≥40 kg/m² undergoing bariatric surgery. Research Methods and Procedures: We developed a nonhomogeneous Markov chain consisting of five states: the absorbing state (“dead”) and the four recurrent states BMI ≥40 kg/m², BMI 36 to 39 kg/m², BMI 32 to 35 kg/m², and BMI 25 to 31 kg/m². Scenarios of weight loss and age‐ and sex‐dependent risk of death, as well as BMI‐dependent excess mortality were extracted from life tables and published literature. All patients entered the model through the state of BMI ≥40 kg/m². Results: In men aged either 18 or 65 years at the time of surgery, who moved from the state BMI ≥40 kg/m² to the next lower state of BMI 36 to 39 kg/m², life expectancy increased by 3 and 0.7 years, respectively. In women aged either 18 or 65 years at the time of surgery, who moved from the state BMI ≥40 kg/m² to the next lower state BMI 36 to 39 kg/m², life expectancy increased by 4.5 and 2.6 years, respectively. Weight loss to lower BMI strata resulted in further gains of life expectancy in both men and women. Discussion: Within the limitations of the modeling study, adjustable gastric banding in patients with morbid obesity may substantially increase life expectancy.     

Wild intersex roach (Rutilus rutilus) have reduced fertility

Endocrine-disrupting chemicals, known to be present in the environment, have great potential for interfering with reproductive health in wildlife and humans. There is, however, little direct evidence that endocrine disruption has adversely affected fertility in any organism. In freshwater and estuarine fish species, for example, although a widespread incidence of intersex has been reported, it is not yet known if intersexuality influences reproductive success. The purpose of this study was, therefore, to determine gamete quality in wild intersex roach (Rutilus rutilus) by assessing sperm characteristics, fertilization success, and ability to produce viable offspring. The results clearly demonstrate that gamete production is reduced in intersex roach. A significantly lower proportion of moderately or severely feminized fish (17.4% and 33.3%, respectively) were able to release milt compared with normal male fish from contaminated rivers (in which 97.6% of the males were able to release milt), reference male fish (97.7%), or less severely feminized intersex fish (experiment 1: 85.8%, experiment 2: 97%). Intersex fish that did produce milt produced up to 50% less (in terms of volume per gram of testis weight) than did histologically normal male fish. Moreover, sperm motility (percentage of motile sperm and curvilinear velocity) and the ability of sperm to successfully fertilize eggs and produce viable offspring were all reduced in intersex fish compared with normal male fish. Male gamete quality (assessed using sperm motility, sperm density, and fertilization success) was negatively correlated with the degree of feminization in intersex fish (r = -0.603; P < 0.001) and was markedly reduced in severely feminized intersex fish by as much as 50% in terms of motility and 75% in terms of fertilization success when compared with either less severely feminized intersex fish or unaffected male fish. This is the first evidence documenting a relationship between the morphological effects (e.g., intersex) of endocrine disruption and the reproductive capabilities of any wild vertebrate. The results suggest that mixtures of endocrine-disrupting substances discharged into the aquatic environment could pose a threat to male reproductive health.     

Prevalence of Pre‐obesity and Obesity in Urban Adult Mexicans in Comparison with Other Large Surveys

Objective: 1. To estimate the prevalence of pre‐obesity and obesity in a 1992 to 1993 national survey of the Mexican urban adult population. 2. To compare our findings with other national surveys and with data for Mexican Americans. Research Methods and Procedures: The national representative sample of the Mexican urban adult population included 8462 women and 5929 men aged 20 to 69 years from 417 towns of >2500 people. Body mass index (BMI), calculated from measured weight and height, was classified using the World Health Organization categories of underweight (BMI < 18.5 kg/m²), normal weight (BMI 18.5 to 24.9 kg/m²), pre‐obesity (PreOB = BMI 25 to 29.9 kg/m²) and obesity (OB = BMI 30+ kg/m²). Estimates for Mexican Americans were calculated from U.S. survey data. Results: Overall, 38% of the Mexican urban adult population were classified as pre‐obese and 21% as obese. Men had a higher prevalence of pre‐obesity than women did at all ages, but women had higher values of obesity. Both pre‐obesity and obesity increased with age up to the age range brackets of 40 to 49 or 50 to 59 years for both men and women. Both pre‐obesity and obesity prevalence estimates were remarkably similar to data for Mexican Americans from 1982 through 1984. Comparison with other large surveys showed that countries differed more in the prevalence of obesity than of pre‐obesity, leading to differences in the PreOB/OB ratio, and that countries also differed in the gender ratio (female/male) for both pre‐obesity and obesity. Discussion: Pre‐obesity and obesity were high in our population and increased with age. Our approach of characterizing large surveys by PreOB/OB and gender ratios appeared promising.     

Differential expression of porcine sperm microRNAs and their association with sperm morphology and motility

MicroRNAs (miRNAs) are involved in nearly every biological process examined to date, but little is known of the identity or function of miRNA in sperm cells or their potential involvement in spermatogenesis. The objective was to identify differences in miRNA expression between normal porcine sperm samples and those exhibiting high percentages of morphological abnormalities or low motility. Quantitative RT-PCR was performed on sperm RNA to compare expression levels of 10 specific miRNAs that are predicted to target genes that code for proteins involved in spermatogenesis, sperm structure, motility, or metabolism. There were increases in the expression of four miRNAs, let-7a, -7d, -7e, and miR-22, in the abnormal group (P < 0.05), whereas miR-15b was decreased compared to controls (P < 0.05). Two miRNAs, let-7d and let-7e, were increased in the low motility group when compared to controls (P < 0.05). Bioinformatic analyses revealed that messenger RNA targets of the differentially expressed miRNAs encode proteins previously described to play roles in sperm function. Although the precise role of miRNA in sperm remains to be determined, their changes as associated with morphology and motility signify a critical biological function. Perhaps they are remnants of spermatogenesis, stored for a later role in fertilization, or are delivered to the oocyte to influence early embryonic development. Although there is no single cause of male infertility, the identification of miRNAs associated with sperm motility, structural integrity, or metabolism could lead to the development of a microarray or real time-based diagnostic assay to provide an assessment of male fertility status.     

Two egg-derived molecules in sperm motility initiation and fertilization in the Pacific herring (Clupea pallasi)

Sperm of the Pacific herring are immotile at spawning. Two egg-derived molecules are capable of initiating sperm motility. One is herring sperm activating protein(s) (HSAPs) and the other is sperm motility initiation factor (SMIF). These two motility initiators differ in their location and association with the chorion, and in thier isoelectric points and molecular weights. In this study we have investigated the roles of these two inducers with respect to motility and fertilization. Using computer analysis of sperm motility, we found that HSAPs, as well as the C-terminal HSAPs peptide, elicit a linear motility pattern, while SMIF induced a highly circular and asymmetric pattern. HSAPs induced a two-fold increase in intracellular calcium, whereas SMIF induced a four-fold increase of motility initiation. SMIF-exposed sperm, preloaded with BAPTA-AM, showed a more linear motility and this motility trajectory decreased with their fertilizing capability. The difference in intracellular calcium levels between HSAPs and SMIF is consistent with the observed linear and circular motility. In the absence of SMIF, HSAPs do not support fertilization. Fertilization is rescued in these experiments if SMIF is reintroduced. We propose that diffusible HSAPs are not essential for fertilization, but enhance sperm-egg collisions via linear motility. SMIF, which is bound to the micropylar region of the chorion, is required for fertilization and induces circular motility that is a prerequisite for sperm to enter the micropylar canal and fertilize the egg.     

How do sperm swim? Molecular mechanisms underlying sperm motility.

Motility is a characteristic function of the male gamete, which allows spermatozoa to actively reach and penetrate the female gamete in organisms with internal and external fertilization. Sperm motility is acquired under the control of many extrinsic and intrinsic factors and is based on the specialized structure of the sperm flagellum. After a brief overview of how the sperm flagellum is organized and works to support cell motility, the present review focuses on the molecular mechanisms and factors involved in the development and maintenance of sperm motility. Data obtained both in organisms with external fertilization, such as fishes and sea urchin, and with internal fertilization, such as Mammals, are critically analyzed. In particular, a great attention has been put on the ionic mechanisms and on the involvement of protein kinases and phosphatases in regulation of sperm motility. A brief overview of the pharmacological and physiological molecules which have been studied for their possible application as therapeutic molecules for in vitro treatment of defects of sperm motility in asthenozoospermic human subjects, is presented. Moreover, we show some preliminary data obtained in our laboratory on the involvement of the phosphatydilinositol 3-kinase and the A kinase anchoring protein (AKAP3) in regulation of motility in human spermatozoa. The last section is dedicated to hyperactivation, a peculiar pattern of motility which is developed in association with capacitation occurring during sperm transit through the female genital tract and which can also be obtained in vitro by incubation in defined media.