NPPC/NPR2 signaling is essential for oocyte meiotic arrest and cumulus oophorus formation during follicular development in the mouse ovary

Natriuretic peptide type C (NPPC) and its high affinity receptor, natriuretic peptide receptor 2 (NPR2), have been assumed to be involved in female reproduction and have recently been shown to play an essential role in maintaining meiotic arrest of oocytes. However, the overall role of NPPC/NPR2 signaling in female reproduction and ovarian function is still less clear. Here we report the defects observed in oocytes and follicles of mice homozygous for Nppc(lbab) or Npr2(cn), mutant alleles of Nppc or Npr2 respectively to clarify the exact consequences of lack of NPPC/NPR2 signaling in female reproductive systems. We found that: i) Npr2(cn)/Npr2(cn) female mice ovulated a comparable number of oocytes as normal mice but never produced a litter; ii) all ovulated oocytes of Npr2(cn)/Npr2(cn) and Nppc(lbab)/Nppc(lbab) mice exhibited abnormalities, such as fragmented or degenerated ooplasm and never developed to the two-cell stage after fertilization; iii) histological examination of the ovaries of Npr2(cn)/Npr2(cn) and Nppc(lbab)/Nppc(lbab) mice showed that oocytes in antral follicles prematurely resumed meiosis and that immediately before ovulation, oocytes showed disorganized chromosomes or fragmented ooplasm; and iv) ovulated oocytes and oocytes in the periovulatory follicles of the mutant mice were devoid of cumulus cells. These findings demonstrate that NPPC/NPR2 signaling is essential for oocyte meiotic arrest and cumulus oophorus formation, which affects female fertility through the production of oocytes with developmental capacity.     

Effect of genetic background and activating stimulus on the timing of meiotic cell cycle progression in parthenogenetically activated mouse oocytes

With the aim of investigating the effects of oocyte genotype and activating stimulus on the timing of nuclear events after activation, oocytes collected from hybrid B6D2F1, inbred C57BL/6 and outbred CF-1 and immunodeficient nude (NU/+) females were activated using ethanol or strontium and fixed at various time-points. Meiotic status, spindle rotation and second polar body (PB2) extrusion were monitored by fluorescence microscopy using DNA-, microtubule- and microfilament-selective probes. Although activation efficiency was similar in all groups of oocytes, a significant percentage of CF-1 and NU/+ oocytes treated with ethanol and of C57BL/6 oocytes treated either with ethanol or strontium failed to complete activation and became arrested at a new metaphase stage (MIII) after PB2 extrusion. C57BL/6 oocytes also showed slower release from MII arrest but faster progression to telophase (TII) after ethanol exposure, and they exhibited the most rapid exit from TII under both activation treatments. Strontium caused delayed meiotic resumption, spindle rotation and PB2 extrusion, but rapid TII exit, in B6D2F1, CF-1 and NU/+ oocytes when compared with ethanol. Compared with all other strains, NU/+ oocytes were significantly slower in completing spindle rotation and PB2 extrusion, irrespective of the activating stimulus, and a significant decrease in activation rates and pace of meiotic progression was observed after strontium exposure. Thus, our findings demonstrated that the kinetics of meiosis resumption and completion, spindle rotation and PB2 extrusion following parthenogenetic activation depends on both genotype-specific factors and on the activation treatment applied.     

The expression of calpain 1 and calpain 2 in spermatogenic cells and spermatozoa of the mouse

There is some evidence suggesting that Ca2+ is involved in processes that occur during the development and function of spermatozoa. Calcium-dependent proteins, such as calmodulin, are expressed during mammalian spermatogenesis further suggesting that Ca2+ takes part in its regulation. However, the precise roles of Ca2+ in spermatogenesis remain to be elucidated. Calpains are a family of Ca(2+)-dependent cysteine proteases whose members are expressed ubiquitously or in a tissue-specific manner. Calpain has been demonstrated to mediate specific Ca(2+)-dependent processes including cell fusion, mitosis and meiosis. We herein followed the expression pattern of calpain's ubiquitous isoforms, 1 and 2, throughout spermatogenesis at the RNA and protein levels by RT-PCR and Western blotting analysis. Both RNA and protein studies revealed that these isoforms are expressed in all spermatogenic cells. The expression of calpain 1 levels is slightly higher in spermatocytes entering the meiotic phase. Both calpain isoforms are also expressed in mouse spermatozoa and are localized to the acrosomal cap. Inducing capacitated spermatozoa to undergo the acrosome reaction in the presence of a selective calpain inhibitor significantly reduced the acrosome reaction rate in a dose-dependent manner. Thus, calpain, a pluripotential protease with numerous substrates, may serve as an effector in more than one pathway in the complex process of spermatogenesis and in the events preceding fertilization, such as the acrosome reaction.     

Different milk feeding intensities during the first 4 weeks of rearing dairy calves: Part 2: Effects on the metabolic and endocrine status during calfhood and around the first lactation

Feeding dairy calves at high intensity has been demonstrated to increase milk yield in later life. We investigated the effect of 3 different feeding regimens in the preweaning period on the metabolic and endocrine status during calfhood and in heifers at the onset of the first lactation. In trial 1, 57 German Holstein calves were allocated to 3 different feeding groups: milk replacer restricted to 6.78 kg/calf per day, 11.5% solids (MR-res, n = 20), milk replacer 13.8% solids, ad libitum (MR-ad lib, n = 17), and whole milk ad libitum (WM-ad lib, n = 20). All calves received ad libitum colostrum for 3 d postnatal (p.n.). From d 4 to 27, all calves were fed according to their respective feeding regimen, resulting in average intakes of 6.38, 9.25, and 9.47 kg/d in MR-res, MR-ad lib, and WM-ad lib, respectively. Thereafter, all calves were fed according to the MR-res regimen until weaning at d 55 (gradually until d 69 p.n.). Blood samples were collected on d 0 before colostrum intake and on d 1, 3, 11, 22, 34, 43, 52, 70, 90, and 108 p.n. Liver biopsies were taken on d 19 and 100, and on d 22, 52, and 108 p.n. intravenous glucose tolerance tests were performed. The male calves (n = 8 to 10 per group) underwent also an insulin tolerance test on d 24, 54, and 110 p.n. The females (n = 28) from trial 1 were further reared and bred as common practice, and were enrolled in trial 2 when beginning the last trimester of pregnancy. Blood samples were collected monthly antepartum starting 91 d before calving and weekly (0–70 d) postpartum. Trial 1 was subdivided into 4 phases (P): P0 (d 0–1), P1 (d 2–27), P2 (d 28–69), and P3 (d 70–110 p.n.). In trial 1, the leptin and adiponectin concentrations increased with colostrum intake. Differences in fatty acids, insulin, adiponectin, revised quantitative insulin sensitivity check index (RQUICKI), and variables from the glucose tolerance tests were largely limited to P1. The MR-res group had greater RQUICKI and fatty acid values, and lower insulin and, as a trend, adiponectin concentrations than in 1 or both ad lib groups. These differences were partly sustained in P2 (fatty acids, adiponectin, and RQUICKI) and in P3 (adiponectin). The hepatic mRNA abundance of the gluconeogenic enzymes phosphoenolpyruvate carboxykinase and pyruvatcarboxylase increased from d 19 to 100. None of the blood variables were different between the groups when tested in pregnancy and lactation. Our results do not support a sustained deflection of metabolic regulation by rearing at different feeding intensities; nevertheless, the differences observed during rearing might influence nutrient utilization in later life or the cellular development of organs, such as the mammary gland, and thereby affect milk yield. Further studies involving greater animal numbers and, thus, improved power will help to sort out the mechanisms of programming body function in later life via nutrition in early life.     

Characterization of mouse sperm TMEM190, a small transmembrane protein with the trefoil domain: evidence for co-localization with IZUMO1 and complex formation with other sperm proteins

TMEM190, a small transmembrane protein containing the trefoil domain, was previously identified by our proteomic analysis of mouse sperm. Two structural features of TMEM190, 'trefoil domain' and 'small transmembrane protein', led us to hypothesize that this protein forms a protein-protein complex required during fertilization, and we characterized TMEM190 by biochemical, cytological, and genetic approaches. We showed in this study that the mouse Tmem190 gene exhibits testis-specific mRNA expression and that the encoded RNA is translated into a 19-kDa protein found in both testicular germ cells and cauda epididymal sperm. Treatment of the cell surface with proteinase K, subcellular fractionation, and immunofluorescence assay all revealed that mouse TMEM190 is an inner-acrosomal membrane protein of cauda epididymal sperm. During the acrosome reaction, TMEM190 partly relocated onto the surface of the equatorial segment, on which sperm-oocyte fusion occurs. Moreover, TMEM190 and IZUMO1, which is an immunoglobulin-like protein required for gamete fusion, co-localized in mouse sperm both before and after the acrosome reaction. However, immunoprecipitates of TMEM190 contained several sperm proteins, but did not include IZUMO1. These findings suggest that a mouse sperm protein complex(es) including TMEM190 plays an indirect role(s) in sperm-oocyte fusion. The role(s), if any, is probably dispensable since Tmem190-null male mice were normally fertile.     

Effect of the expression of aquaporins 1 and 3 in mouse oocytes and compacted eight-cell embryos on the nucleation temperature for intracellular ice formation

The occurrence of intracellular ice formation (IIF) is the most important factor determining whether cells survive a cryopreservation procedure. What is not clear is the mechanism or route by which an external ice crystal can traverse the plasma membrane and cause the heterogeneous nucleation of the supercooled solution within the cell. We have hypothesized that one route is through preexisting pores in aquaporin (AQP) proteins that span the plasma membranes of many cell types. Since the plasma membrane of mature mouse oocytes expresses little AQP, we compared the ice nucleation temperature of native oocytes with that of oocytes induced to express AQP1 and AQP3. The oocytes were suspended in 1.0 M ethylene glycol in PBS for 15 min, cooled in a Linkam cryostage to -7.0 ° C, induced to freeze externally, and finally cooled at 20 ° C/min to -70 ° C. IIF that occurred during the 20 ° C/min cooling is manifested by abrupt black flashing. The mean IIF temperatures for native oocytes, for oocytes sham injected with water, for oocytes expressing AQP1, and for those expressing AQP3 were -34, -40, -35, and -25 ° C respectively. The fact that the ice nucleation temperature of oocytes expressing AQP3 was 10-15 ° C higher than the others is consistent with our hypothesis. AQP3 pores can supposedly be closed by low pH or by treatment with double-stranded Aqp3 RNA. However, when morulae were subjected to such treatments, the IIF temperature still remained high. A possible explanation is suggested.     

Effects of leptin administration and feed restriction on thecal leucocytes in the preovulatory rat ovary and the effects of leptin on meiotic maturation,granulosa cell proliferation,steroid hormone and PGE2 release in cultured rat ovarian follicles

Leptin is expressed by adipocytes and is thought to play a role in regulating food intake and in reproduction. It has been demonstrated that acute leptin administration to immature gonadotrophin-primed rats in vivo inhibits ovulation and causes a decline in food intake. However, feed restriction alone does not inhibit ovulation. Two experiments were designed to investigate the mechanism of leptin-induced inhibition of ovulation. In the first experiment, which was prompted by the importance of ovarian leucocytes in ovulation, the role of leucocytes in leptin-induced inhibition of ovulation was investigated. The second experiment investigated whether high leptin concentrations could inhibit other factors important to ovulation, such as meiotic competence of oocytes, granulosa cell proliferation, steroid or PGE(2) release, and interleukin 1beta production, in vitro. In the first experiment, the populations of neutrophils and monocytes-macrophages in the preovulatory follicles of gonadotrophin-primed, leptin-treated and -untreated rats were examined. A decrease in food intake, as a result of either leptin treatment or feed restriction, specifically reduced the numbers of neutrophils and monocytes-macrophages infiltrating the theca interna of preovulatory follicles without affecting the numbers found in the stroma. The findings show that reduced infiltration of thecal neutrophils and macrophages into preovulatory follicles is a response to reduced food intake. Furthermore, this reduction is not the direct cause of the leptin-induced inhibition of ovulation. In the second experiment, ovarian follicles were cultured for 4 or 12 h in the presence or absence of the following hormones: FSH (500 miu), insulin-like growth factor I (IGF-I) (50 ng ml(-1)), LH (100 ng ml(-1)) and leptin (300 ng ml(-1)). The results demonstrated that high concentrations of leptin in follicle culture do not affect meiotic maturation or steroid release, but tend to inhibit release of PGE 2 (although this result was not significant). DNA synthesis in granulosa cells was not inhibited by leptin in FSH- and IGF-I-supplemented culture media. These results are in agreement with previous studies that have shown that leptin inhibits the stimulatory effects of IGF-I on FSH-stimulated oestradiol production in rat granulosa cells without affecting progesterone production. In summary, leptin does not appear to have an adverse effect on the components of ovulation tested in this study, and therefore must impact on the ovulatory cascade in a way that remains to be defined.     

四平针2+1罗纹的减针留边工艺研究

通过分析四平针2+1罗纹和相对2+2罗纹的组织结构和外观特点,绘制编织意匠图和结构图.在四平针2+1罗纹组织结构基础上,详细介绍两种减针留边工艺,包括四平针2+1罗纹的减针留边和相对2+2罗纹的减针留边,并在双针床电脑横机上编织羊毛衫实物.结果表明:四平针2+1罗纹组织结构的两种减针留边工艺均能满足产品设计需求,确保产...     

Effect of polymorphisms in the leptin, leptin receptor, and acyl-coenzyme A:diacylglycerol acyltransferase 1 (DGAT1) genes and genetic polymorphism of milk proteins on cheese characteristics

Cheese production has increased worldwide during the last decade and is expected to increase within the coming decade as well. Despite this, the relations between cow genetics and cheese characteristics are not fully known. The aim of this study was to determine if polymorphisms in the leptin (LEP), leptin receptor (LEPR), and acyl-coenzyme A:diacylglycerol acyltransferase 1 (DGAT1) genes as well as genetic variants of β-casein (β-CN), κ-CN, and β-lactoglobulin (β-LG) affect technological properties important for cheese production and, hence, could act as genetic makers for cheese quality. Individual milk samples from the Swedish Red and the Swedish Holstein breeds were analyzed for sizes of CN micelles and fat globules as well as rennet-induced gel strength, gelation time, and yield stress. Model cheeses were produced to study yield, hardness, and pH of the cheeses. The A1457G, A252T, A59V, and C963T single nucleotide polymorphisms (SNP) were analyzed on the LEP gene, the T945M SNP on the LEPR gene, and the Nt984+8(A-G) SNP on the DGAT1 gene. In addition, genetic variants of β-CN, κ-CN, and β-LG were determined. The results indicate that technological properties were influenced by the LEPR_T945M polymorphism, which had an association with gel strength, yield stress, and cheese hardness (T > C). However, also LEP_A252T was shown to affect gel strength (T > A), whereas the LEP_A59V had an effect on fat globule size (T > C). For the milk protein genes, favorable effects were found for the A and B variants of β-LG and κ-CN, respectively, on gel strength, gelation time, and yield stress. In addition, the B variant of κ-CN was shown to be associated with smaller CN micelles than the A variant. Thus, the results demonstrate potential genetic markers for cheese characteristics. However, milk composition traits also affected the obtained results, thus making it necessary to thoroughly assess the different aspects regarding the influence of gene effects on cheese characteristics before directly selecting for certain alleles or genetic variants to improve the processing and quality of cheese.     

Randomized clinical trial of the effect of a fixed or increasing milk allowance in the first 2 weeks of life on health and performance of dairy calves

The objective of this study was to describe the effect of offering a fixed or increasing milk allowance in the first 1 to 2 wk of life. We hypothesized that calves offered a fixed amount of milk early in life would not experience more scours, but rather would experience improved health and growth compared with calves that had their daily milk allowance slowly increased over a period of 1 to 2 wk. This randomized controlled clinical trial was conducted on 5 dairy farms in Minnesota with both a summer (June–August 2016) and winter (December–February 2017) period of enrollment. Heifer calves were enrolled at birth, weighed, and systematically assigned by birth order to either the slowly increasing (INC) control group or fixed allowance (FIX) treatment group by farm personnel. Calves assigned to the INC group were slowly increased from 4 to 5 L/d to gradually reach the full peak milk allowance of 6 to 8 L/d over a 7- to 14-d period, whereas calves assigned to the FIX group were offered a full peak milk allowance of 6 to 8 L/d beginning on d 1 after birth. The average FIX calf consumed an extra 14 L of milk as compared with INC calves over the first 2 wk of life, corresponding to an average INC intake of 5 L/d during first 1 to 2 wk of life as compared with an average intake of 6.8 L/d in FIX calves. Study technicians visited all farms weekly to collect health and performance data. Multivariable mixed models were used to describe the effect of treatment (INC/FIX) on 3-wk average daily gain (kg/d), 3-wk weight (kg), and hip height at wk 1, 3, and 7, controlling for the effect of season, birth weight, and the random effect of calf within farm. Multivariable logistic regression models were used to describe the effect of treatment on odds of technician and producer reported health events. A total of 1,264 heifer calves were enrolled (FIX n = 641; INC n = 623) with no difference in enrollment weight or hip height between groups. By 3 wk of age, FIX calves weighed 1.4 (0.59) kg more than INC calves, though the magnitude of this difference varied depending on the period of time INC calves were slowly increased in milk allowance (7 vs. 10 vs. 14 d). Calves in the FIX group grew 0.1 kg/d faster and were taller at wk 3 (0.3 ± 0.15 cm) of life. Forty-two percent (536/1,264) of all enrolled calves had a first treatment event, with no effect of treatment on technician-reported health scores and no overall effect on producer-reported treatment or mortality events. Under the conditions of this study, offering a fixed milk allowance from d 1 of life improved calf growth during the first 3 wk as compared with a gradual increase in milk allowance, with no detrimental effect on calf health.     

The α-amylase, α-amylase inhibitor and proteinase inhibitor activities of proteins extracted from wheat varieties and their influence on the baking quality

The grain of six winter and spring wheat varieties, harvested in 1987, differing in baking quality were included in the study. A number of technological analysis were performed. Albumins, globulins and gliadins were washed out. The location of inhibitory activities in extracted proteins, against α-amylases of various origin. were tested and compared to the baking quality of the wheat grain. Also, the location of antitryptic activity and endogenous amylase activity in extractable proteins was compared to baking quality factors. Among the studied inhibitory activities against mammalian α-amylases some correlation were found between the inhibition activity of hog pancreas α-amylase and sedimentation test (r = 0.88). Furthermore inhibitory activities of wheat proteins towards insects α-amylase shown significant correlation between the inhibitors of Anagasta kuehniella α-amylase and sedimentation test (r = 0.90). as well as crude protein content (r = 0.86). Also the inhibition activity against Sitophilus granarius α-amylase versus sedimentation test presented some correlation (r = 0.80). Endogenous amylase activities (α- and β-amylase) have an inversely proportional correlation to crude protein content (r = ?0.82) and sedimentation test (r = ?0.85).     

1-MCP和CO_2自发释放处理对西兰花常温货架期的保鲜作用

以新鲜西兰花为原料,用自发释放浓度为2.5μg/L 1-甲基环丙烯(1-MCP)和5%CO2作为保鲜剂,对西兰花在常温货架进行贮藏处理,以加冰和不做处理为对照,在(20±3)℃下对西兰花的相关指标进行定期测定。结果表明:自发释放CO2处理能够显著延缓西兰花V C含量的减少,并且能够有效抑制西兰花叶绿素含量的下降;自发释放1-MCP处理能够有效降低西兰花呼吸作用,推迟呼吸高峰并使呼吸高峰降低,同时可以延缓可溶性固形物的减少。自发释放1-MCP和CO2处理与2个对照相比均能延长西兰花的货架时间,起到保鲜效果。     

Single-Laboratory Validation for the Determination of Aflatoxin B1, B2, G1, and G2 in Foods Based on Immunoaffinity Column and Liquid Chromatography with Postcolumn Derivatization and Fluorescence Detection

This study presents a method validation procedure for the determination of aflatoxin B₁, B₂, G₁, and G₂ in hazelnut, hazelnut paste, walnut, peanut, pistachio, corn, and wheat. The method consisting of clean-up with immunoaffinity column, high performance liquid chromatography with postcolumn derivatization and fluorescence detection was validated in accordance with Commission Regulation 2004/882/EC. The selectivity, linearity, decision limit, detection capability, detection and quantification limits, precision, recovery, ruggedness, and measurement uncertainty of the method were determined. The limit of detection and limit of quantification values (μg/kg) were: aflatoxin B₁, 0.02, 0.07; aflatoxin B₂, 0.01, 0.02; aflatoxin G₁, 0.02, 0.07; and aflatoxin G₂, 0.01, 0.03. The relative standard deviation values for the repeatability and within-laboratory reproducibility were below 4 and 5 %, respectively. The recovery values of the spiked samples ranged from 80 to 105 %. These results complied with minimum performance criteria established by regulation 2006/401/EC. Therefore, the procedure can be implemented for the routine analysis of aflatoxins in the studied matrices.     

A 'minimum dose' of lipopolysaccharide required for implantation failure: assessment of its effect on the maternal reproductive organs and interleukin-1alpha expression in the mouse

Genital tract infections caused by gram-negative bacteria induce abortion and are one of the most common complications of human pregnancy. This study was carried out to decipher the mechanism of gram-negative bacterial lipopolysaccharide (LPS)-induced pregnancy loss, using a mouse (Park strain) model. Since many of the biological effects of LPS are mediated by interleukin (IL)-1alpha, the role of IL-1alpha in LPS-induced pregnancy loss was studied. Pregnant female animals were injected intra-peritoneally (i.p.) with different doses (1 to 50 microg) of LPS from Salmonella minnesota Re-595, on day 0.5 of pregnancy. We found that 250 microg/kg body weight (i.e. 5 microg/female mouse) of LPS when given on day 0.5 of pregnancy was the 'minimum dose' (MD) required to completely inhibit the implantation of the blastocyst in the mouse. The effect of this dose on the pathophysiology of the various reproductive organs (i.e. uterus, ectoplacental cones, developing fetus, ovaries etc.) was assessed on day 14 of pregnancy. The effects of this dose on the level and pattern of expression of the proinflammatory cytokine IL-1alpha in the maternal uterine horns and preimplantation stage embryos were studied by RT-PCR. A single dose (100 ng/mouse) of recombinant mouse IL-1alpha was given i.p. to pregnant females on day 1 of pregnancy to study its effect on implantation. Our results show that treatment of the pregnant animals with LPS may alter cell proliferation and induce leukocyte infiltration, degeneration of luminal glandular epithelium, and hyperplasia in the various reproductive organs, and may also alter both embryonic and uterine IL-1alpha expression. IL-1alpha administration also caused implantation failure similar to that of LPS. The observations suggest that the determined MD of LPS may alter the expression of developmentally important proinflammatory cytokines such as IL-1alpha, which could, in turn, inhibit the normal processes of blastocyst implantation. Therefore, it is proposed that the LPS-induced histopathological alterations in the various reproductive organs of pregnant animals could be mediated by IL-1alpha and this may be one of the causes of failure of blastocyst implantation in the mouse.     

奥美拉唑、兰索拉唑和泮托拉唑对药物代谢酶CYP1A2活性影响的研究

目的探讨奥美拉唑、兰索拉唑和泮托拉唑对药物代谢酶CYP1A2活性的影响,预测奥美拉唑、兰索拉唑和泮托拉唑与常用药物的相互作用,以指导临床医师合理用药。方法以咖啡因作为药物代谢酶CYP1A2的探针药物,以反相高效液相梯度洗脱法测定90名受试者分别服用奥美拉唑、兰索拉唑和泮托拉唑前后尿液内咖啡因4种主要代谢产物的相对含量,采用代谢物的比率评价药物代谢酶CYP1A2活性的变化。结果服用奥美拉唑、兰索拉唑和泮托拉唑3种质子泵抑制剂前CYP1A2平均活性分别为5.36±2.10,3.64±1.92,3.37±1.22;服药后活性分别为5.83±2.37,4.02±2.17,3.50±1.23,服药前后药物代谢酶CYP1A2活性无统计学意义(P>0.05)。结论服用治疗剂量的奥美拉唑、兰索拉唑和泮托拉唑7d后,药物代谢酶CYP1A2活性无明显影响,奥美拉唑、兰索拉唑和泮托拉唑可能不会影响与之合用的需经CYP1A2代谢的药物疗效。     

花生致敏蛋白Ara h1和Ara h2纯化鉴定方法研究进展

对主要花生过敏蛋白Ara h1和Ara h2的提取纯化方法以及纯化后Ara h1、Ara h2的鉴定方法进行了综述。     

IIX. Yeast mapping reports. ATP1 and ATP2, the F1F0-ATPase α and β subunit genes of Saccharomyces cerevisiae,are respectively located on chromosomes II and X

Southern blot analysis showed that ATP1 and ATP2 map on chromosomes II and X, respectively. Physical mapping of ATP1 and ATP2 by chromosome fragmentation showed that ATP1 is at the left end of chromosome II and ATP2 is at the right end of chromosome X. Both are located close to telomere sequences of each chromosome; ATP1 and ATP2 being approximately 30 kb and 85 kb from the respective telomeres.