[Analysis on personal protection in occupational population at high risk for brucellosis and influencing factor in China]

Objective: To understand the current status of personal protection in occupational population at high risk for brucellosis in China and provide evidence for the evaluation of implementation of National Brucellosis Prevention and Control Plan (2016-2020). Methods: Four counties in Shanxi Province and Xinjiang Uygur Autonomous Region were selected to conduct a questionnaire survey in occupational population at high risk for brucellosis from December 2019 to July 2020 by using cross-sectional survey methods. Results: A total of 2 384 persons at high risk for brucellosis were surveyed, and the standardized utilization rate of personal protective equipment (PPE) was 20.13% (480/2 384). The utilization rate of glove, mask, rubber shoe, and work cloth were 38.26% (912/2 384), 31.80% (758/2 384), 32.01% (763/2 384) and 30.87% (736/2 384),respectively. There were significant differences in the utilization rate and standardized utilization rate of the four types of PPE among populations in different age, occupation, educational level and area groups (all P<0.001). The utilization rate and standardized utilization rate of PPE were lower in people over 60 years old, women, farmers, and those with lower educational level. The results of multivariate analysis showed that occupation and area were the influencing factors for the standardized utilization of PPE, the standardized utilization rates of PPE were higher in herdsmen and veterinarians. The standardized utilization rate of PPE in Yanggao County and Huocheng County was significantly higher than that in Zuoyun County and Hunyuan County. Conclusions: The utilization rate of the four types of PPE in occupational population at high risk for brucellosis was not high in China, and the standardized utilization rate was low, lower than the requirement in National Brucellosis Prevention and Control Plan, and there were significant differences among different areas. It is urgent to distribute PPE to occupational population at high risk for brucellosis and carry out health education about PPE utilization. Meanwhile, it is necessary to strengthen information exchange or sharing among different areas.

A long-acting recombinant FSH supports high-quality mouse follicle development and oocyte maturation in vitro by co-ordinating somatic and germ cell transcriptomes

Strategies to maximize individual fertility chances are constant requirements of ART In vitro folliculogenesis may represent a valid option to create a large source of immature ovarian follicles in ART. Efforts are being made to set up mammalian follicle culture protocols with suitable FSH stimuli. In this study, a new type of recombinant FSH (KN015) with a prolonged half-life is proposed as an alternative to canonical FSH. KN015 supports the in vitro development of mouse follicles from primary to preovulatory stage with higher efficiency than canonical FSH and enhanced post-fertilization development rates of the ovulated oocytes. The use of KN015 also allows us to compare the dynamic transcriptome changes in oocytes and granulosa cells at different stages, in vivo and in vitro. In particular, KN015 facilitates mRNA accumulation in growing mouse oocytes and prevents spontaneous luteinization of granulosa cells in vitro. Novel analyses of transcriptome changes in this study reveal that the in vivo oocytes were more efficient than in vitro oocytes in terms of maternal mRNA clearing during meiotic maturation. KN015 promotes the degradation of maternal mRNA during in vitro oocyte maturation, improves cytoplasmic maturation and, therefore, enhances embryonic developmental potential. These findings establish new transcriptome data for oocyte and granulosa cells at the key stages of follicle development, and should help to widen the use of KN015 as a valid and commercially available hormonal support enabling optimized in vitro development of follicles and oocytes.

Transcriptome analysis revealed differences in the microenvironment of spermatogonial stem cells in seminiferous tubules between pre-pubertal and adult buffaloes

The microenvironment in the seminiferous tubules of buffalo changes with age, which affects the self-renewal and growth of spermatogonial stem cells (SSCs) and the process of spermatogenesis, but the mechanism remains to be elucidated. RNA-seq was performed to compare the transcript profiles of pre-pubertal buffalo (PUB) and adult buffalo (ADU) seminiferous tubules. In total, 17,299 genes from PUB and ADU seminiferous tubules identified through RNA-seq, among which 12,271 were expressed in PUB and ADU seminiferous tubules, 4,027 were expressed in only ADU seminiferous tubules, and 956 were expressed in only PUB seminiferous tubules. Of the 17,299 genes, we identified 13,714 genes that had significant differences in expression levels between PUB and ADU through GO enrichment analysis. Among these genes, 5,342 were significantly upregulated and possibly related to the formation or identity of the surface antigen on SSCs during self-renewal; 7,832 genes were significantly downregulated, indicating that genes in PUB seminiferous tubules do not participate in the biological processes of sperm differentiation or formation in this phase compared with those in ADU seminiferous tubules. Subsequently, through the combination with KEGG analysis, we detected enrichment in a number of genes related to the development of spermatogonial stem cells, providing a reference for study of the development mechanism of buffalo spermatogonial stem cells in the future. In conclusion, our data provide detailed information on the mRNA transcriptomes in PUB and ADU seminiferous tubules, revealing the crucial factors involved in maintaining the microenvironment and providing a reference for further in vitro cultivation of SSCs.

Genome-wide analysis reveals genetic diversity, linkage disequilibrium, and selection for milk production traits in Chinese buffalo breeds

The water buffalo is an important dual-purpose livestock that is widespread throughout central and southern China. However, there has been no characterization of the population genetics of Chinese buffalo. Using an Axiom buffalo genotyping array (Thermo Fisher Scientific, Wilmington, DE), we analyzed the genetic diversity, linkage disequilibrium pattern, and signature of selection in 176 Chinese buffaloes from 13 breeds. A total of 35,547 SNP passed quality control and were used for further analyses. Population genetic analysis revealed a clear separation between swamp and river types. Ten Chinese indigenous breeds were clustered into the swamp group, the Murrah and Nili-Ravi breeds were clustered into the river group, and the crossbred breed was closer to the river group. Genetic diversity analysis showed that the swamp group had a lower average expected heterozygosity. Linkage disequilibrium decay distance was much shorter in the swamp group compared with the river group, with an average square of correlation coefficient value of 0.2 of approximately 50 kb. Analysis of runs of homozygosity indicated extensive remote and recent inbreeding within swamp and river groups, respectively. Moreover, one genomic region under selection was detected between the river and swamp groups. Our findings contribute to our understanding of the characterization of population genetics in Chinese buffaloes, which in turn may be used in buffalo breeding programs.

[Occupational characteristics and clinical manifestations of 245 cases of occupational brucellosis]

Objective: To analyse epidemiological, clinical characteristics and laboratory examination results of 245 occupational brucellosis form 2008 to 2018, which providing theoretical basis for prevention and control of occupational brucellosis. Methods: Based on the China Center for Disease Control and Prevention Information System, a database of occupational brucellosis cases in HunlunBuir from January 2008 to July 2018 was established. The Epidemiological characteristics, Clinical manifestation, laboratory examination of 245 occupational brucellosis and 359 without occupational brucellosis were comparatively analyzed about the same period. Results: Among the 245 patients, 219 were males, 254 in 359, malese were significantly higher than control group (χ(2)=21.331, P<0.05) . Fever, fatigue, hyperhidrosis and splenomegaly are common in patients with occupational brucellosis and non occupational brucellosis. Arthralgia (54.3%/44.8%) and CRP (81.2%/71.3%) were significantly also higher than control group (χ(2)=5.193, P<0.05; χ(2)=7.704, P<0.05) Fever, hyperhidrosis, fatigue and splenomegaly were common clinical manifestation and signs in the two groups. Brucellosis can cause a variety of complications, including osteoarticular hematological system and hepatic involvement, some patients with multiple system damage. Conclusion: The incidence of occupational brucellosis in HulunBuir is concentrated in agriculture and animal husbandry. Veterinarians are the main occupational groups, Occupational health interventions should be strengthened for key occupational hazards, regular occupational health examination, avoid chronic brucellosis and protect the health of key occupational groups.

Maturation of buffalo oocytes in vitro with acetyl-L-carnitine improves cryotolerance due to changes in mitochondrial function and the membrane lipid profile

The effects of acetyl-l-carnitine (ALC) supplementation during IVM on subsequently vitrified buffalo oocytes were evaluated, followed by determination of the mitochondrial DNA copy number, measurement of mitochondrial membrane potential (MMP) and identification of the lipid profile of oocyte membranes as markers of oocyte quality after vitrification. Supplementation with ALC during IVM significantly improved the rates of oocyte cleavage and morula and blastocyst formation, and increased MMP after vitrification compared with unsupplemented vitrified oocytes (P&lt;0.05). Using a bidirectional orthogonal projection to latent structures discriminant analysis based on positive ion matrix-assisted laser desorption ionisation time-of-flight mass spectrometry data, five phospholipid ions (m/z 728.7 (phosphatidylcholine (PC) 32:3), 746.9 (PC 32:5), 760.6 (PC 34:1), 768.8 (PC P-36:3) and 782.6 (PC 36:4); P&lt;0.05) were identified as significantly more abundant in fresh oocytes than in unsupplemented vitrified oocytes. Meanwhile, three phospholipid ions (m/z 734.6 (PC 32:0), 760.6 (PC 34:1), and 782.6 (PC 36:4); P&lt;0.05) were more abundant in ALC-supplemented vitrified oocytes than in unsupplemented vitrified oocytes. Therefore, supplementation with ALC during IVM may improve buffalo oocyte quality after vitrification by enhancing mitochondrial function and altering the phospholipid composition of vitrified oocyte membranes.

Nanos2 is a molecular marker of inchoate buffalo spermatogonia

Nanos2 belongs to the Nanos gene-coding family and is an important RNA-binding protein that has been shown to have essential roles in male germline stem cells development and self-renewal in mouse. However, little is known about Nanos2 in inchoate buffalo spermatogonia. Here, rapid-amplification of cDNA ends (RACE) was used to obtain the full-length buffalo Nanos2 sequence and bioinformatic analysis revealed a highly conserved Nanos2 sequence between buffalo and other mammalian species. Although Nanos2 was expressed in various tissues, the highest mRNA expression levels were found in testes tissue. Moreover, Nanos2 mRNA was abundant in fetal and pre-puberal testes but markedly decreased in the testes of adults. At the protein level, immunohistochemistry in pre-puberal testes revealed a pattern of NANOS2 expression similar to that for the undifferentiated type A spermatogonia marker PGP9.5. Furthermore, NANOS2 expression was low in adult testes and restricted to elongating spermatids. Altogether, our data suggest that Nanos2 is a potential preliminary molecular marker of inchoate buffalo spermatogonia, and may play an important role in buffalo spermatogonial stem cells (SSCs) development and self-renewal, as has been observed in other model animals.

Superovulation induces defective methylation in line-1 retrotransposon elements in blastocyst

BACKGROUND

Series of epigenetic events happen during preimplantation development. Therefore assistant reproduction techniques (ART) have the potential to disrupt epigenetic regulation during embryo development. The purpose of this study was to investigate whether defects in methylation patterns in blastocyst due to superovulation originate from abnormal expression of Dnmts.

METHODS

Low- (6 IU) and high- (10 IU) dosage of PMSG was used to stimulate the female mice. The metaphase II(MII) oocytes, zygotes and blastocyst stage embryos were collected. Global methylation and methylation at H3K9 in zygote, and methylation at repeated sequence Line 1 and IAP in blastocysts were assayed. In addition, expression of Dnmts was examined in oocytes and zygotes.

RESULTS

Global DNA methylation and methylation at H3K9 in zygotes derived from females after low- or high-dosage hormone treatment were unaltered compared to that in controls. Moreover, DNA methylation at IAP in blastocysts was also unaffected, regardless of hormone dosage. In contrast, methylation at Line1 decreased when high-dose hormone was administered. Unexpectedly, expression of Dnmt3a, Dnmt3b, Dnmt3L as well as maintenance Dnmt1o in oocytes and zygotes was not disrupted.

CONCLUSIONS

The results suggest that defects in embryonic methylation patterns do not originate from the disruption of Dnmt expression.

Maternal diabetes causes alterations of DNA methylation statuses of some imprinted genes in murine oocytes

Maternal diabetes has adverse effects not only on oocyte quality but also on embryo development. However, it is still unknown whether the DNA imprinting in oocytes is altered by diabetes. By using streptozotocin (STZ)-induced and nonobese diabetic (NOD) mouse models we investigated the effect of maternal diabetes on DNA methylation of imprinted genes in oocytes. Mice which were judged as being diabetic 4 days after STZ injection were used for experiments. In superovulated oocytes of diabetic mice, the methylation pattern of Peg3 differential methylation regions (DMR) was affected in a time-dependent manner, and evident demethylation was observed on Day 35 after STZ injection. The expression level of DNA methyltransferases (DNMTs) was also decreased in a time-dependent manner in diabetic oocytes. However, the methylation patterns of H19 and Snrpn DMRs were not significantly altered by maternal diabetes, although there were some changes in Snrpn. In NOD mice, the methylation pattern of Peg3 was similar to that of STZ-induced mice. Embryo development was adversely affected by maternal diabetes; however, no evident imprinting abnormality was observed in oocytes from female offspring derived from a diabetic mother. These results indicate that maternal diabetes has adverse effects on DNA methylation of maternally imprinted gene Peg3 in oocytes of a diabetic female in a time-dependent manner, but methylation in offspring's oocytes is normal.

Cloning and sequencing of the rDNA gene family of the water buffalo (Bubalus bubalis)

The rDNA genes coding for ribosomal RNA in animals are complicated repeat sequences with high GC content. We amplified water buffalo rDNA gene sequences with the long and accurate (LA) PCR method, using LA Taq DNA polymerase and GC buffer, based on bioinformatic analysis of related organisms. The rDNA genes were found to consist of 9016 nucleotides, including three rRNA genes and two internal transcribed spacers (ITS), which we named 18S rRNA, ITS1, 5.8S rRNA, ITS2 and 28S rRNA. We tested and optimized conditions for cloning these complicated rDNA sequences, including specific rules of primer design, improvements in the reaction system, and selection of the DNA polymerase.

The roles of parathyroid hormone-like hormone during mouse preimplantation embryonic development

Parathyroid hormone-like hormone (PTHLH) was first identified as a parathyroid hormone (PTH)-like factor responsible for humoral hypercalcemia in malignancies in the 1980s. Previous studies demonstrated that PTHLH is expressed in multiple tissues and is an important regulator of cellular and organ growth, development, migration, differentiation, and survival. However, there is a lack of data on the expression and function of PTHLH during preimplantation embryonic development. In this study, we investigated the expression characteristics and functions of PTHLH during mouse preimplantation embryonic development. The results show that Pthlh is expressed in mouse oocytes and preimplantation embryos at all developmental stages, with the highest expression at the MII stage of the oocytes and the lowest expression at the blastocyst stage of the preimplantation embryos. The siRNA-mediated depletion of Pthlh at the MII stage oocytes or the 1-cell stage embryos significantly decreased the blastocyst formation rate, while this effect could be corrected by culturing the Pthlh depleted embryos in the medium containing PTHLH protein. Moreover, expression of the pluripotency-related genes Nanog and Pou5f1 was significantly reduced in Pthlh-depleted embryos at the morula stage. Additionally, histone acetylation patterns were altered by Pthlh depletion. These results suggest that PTHLH plays important roles during mouse preimplantation embryonic development.

Active DNA demethylation in mammalian preimplantation embryos: new insights and new perspectives

DNA methylation and demethylation are crucial for modulating gene expression and regulating cell differentiation. Functions and mechanisms of DNA methylation/demethylation in mammalian embryos are still far from being understood clearly. In this review we firstly describe new insights into DNA demethylation mechanisms, and secondly introduce the differences in active DNA methylation patterns in zygotes and early embryos in various mammalian species. Thirdly, we attempt to clarify the functions of DNA demethylation in early embryos. Most importantly we summarize the importance of active DNA demethylation and its possible relevance to human IVF clinics. Finally research perspectives regarding DNA demethylation are also discussed.

Effect of postovulatory oocyte aging on DNA methylation imprinting acquisition in offspring oocytes

OBJECTIVE

To investigate whether postovulatory aging of oocytes in the mother affects DNA methylation acquisition of imprinted genes in oocytes from the offspring.

DESIGN

Randomized research experimental study.

SETTING

Academic basic research laboratory.

ANIMAL(S)

Mice.

INTERVENTION(S)

Fresh oocytes and aged oocytes from mothers were artificially inseminated, and oocytes were collected from the resultant offspring.

MAIN OUTCOME MEASURE(S)

Methylation status was evaluated at differentially methylated regions (DMRs) in oocytes of maternally imprinted genes Peg3, Snrpn, and Peg1 and paternally imprinted gene H19.

RESULT(S)

Our results showed that methylation patterns at DMRs of Peg3, Snrpn, Peg1, and H19 in oocytes from aged-oocyte offspring were mainly normal, with only a small number of oocytes showing aberrant methylation in the DMR of Peg3.

CONCLUSION(S)

Postovulatory oocyte aging causes a decline in reproductive outcomes but does not evidently lead to defects in DNA methylation imprinting acquisition in the oocytes from viable offspring.

An inter-subspecies cloned buffalo (Bubalus bubalis) obtained by transferring of cryopreserved embryos via somatic cell nuclear transfer

The aim of this study was to explore the feasibility of cryopreservation of inter-subspecies cloned embryos in buffalo. In our experiment, river buffalo ear fibroblast nucleus was fused into swamp buffalo oocyte cytoplasm. The blastocyst formation rate for nuclear transfer of freshly thawed cells was not different from those of growing cells, confluent or serum-starved cells. A total of 122 cloned blastocysts derived from cryopreserved fibroblasts were cryopreserved and thawed, 37 were survived, the cryosurvival rate was 30.3%. The survived blastocysts were transferred into 15 recipient buffalos. Five of the recipients established pregnancy, but four of them aborted on day 53, 59, 145 and 179 of gestation respectively. One cross-bred buffalo (Murrah × Swamp buffalo (2n = 49) received three embryos delivered a 40.5 kg female calf by natural delivery on day 320 of gestation. Up to now (13-month old), the cloned calf has been growing well with no abnormity observed. These results demonstrated that cryopreservation of inter-subspecies cloned embryos is feasible to produce buffalo offspring.

Study on the inter-subspecies nuclear transfer of river buffalo somatic cell nuclei into swamp buffalo oocyte cytoplasm

The objective of this study was to explore the feasibility of inter-subspecies somatic cell nuclear transfer (SCNT) of river buffalo (50 chromosomes) somatic cell nuclei into swamp buffalo (48 chromosomes) oocyte cytoplasm. The enucleated swamp buffalo oocytes were fused with four different types of river buffalo cells: freshly thawed ear fibroblasts, serum-starved ear fibroblasts, cumulus cells and ear fibroblasts from a cloned buffalo calf. As a result, the developmental competence of embryos reconstructed with freshly thawed ear fibroblasts was the poorest (P<0.01), while those of the other three types were not different from each other. Furthermore, the efficiency of swamp-swamp buffalo, swamp-river buffalo and bovine-buffalo SCNT were also compared. The results showed that the blastocyst rate of swamp-river reconstructed embryos was not different from swamp-swamp embryos, while significantly higher than that of bovine-buffalo embryos (P<0.01). A total of thirty cloned blastocysts derived from freshly thawed ear fibroblasts were transferred into thirteen recipient buffaloes, four recipients established pregnancy, while three of them aborted on Days 65, 75 and 90 of gestation, respectively. One cross-bred buffalo (Murrah x swamp, 49 chromosomes) receiving three embryos delivered a 39 kg female calf on Day 335 of gestation. These results indicate that the inter-subspecies SCNT is feasible to produce swamp-river buffalo embryos, and these can develop to full term and result in live buffalo calves.

BubR1 is a spindle assembly checkpoint protein regulating meiotic cell cycle progression of mouse oocyte

BubR1 (Bub1-related kinase or MAD3/Bub1b) is an essential component of the spindle assembly checkpoint (SAC) and plays an important role in kinetochore localization of other spindle checkpoint proteins in mitosis. But its roles in mammalian oocyte meiosis are unclear. In the present study, we examined the expression, localization and function of BubR1 during mouse oocyte meiotic maturation. The expression level of BubR1 increased progressively from germinal vesicle to metaphase II stages. Immunofluorescent analysis showed that BubR1 localized to kinetochores from the germinal vesicle breakdown to the prometaphase I stages, co-localizing with polo-like kinase 1, while it disappeared from the kinetochores at the metaphase I stage. Spindle disruption by nocodazole treatment caused relocation of BubR1 to kinetochores at metaphase I, anaphase I and metaphase II stages; spindle microtubules were disrupted by low temperature treatment in the BubR1-depleted oocytes in meiosis I, suggesting that BubR1 monitors kinetochore-microtubule (K-MT) attachments. Over-expression of exogenous BubR1 arrested oocyte meiosis maturation at the M I stage or earlier; in contrast, dominant-negative BubR1 and BubR1 depletion accelerated meiotic progression. In the BubR1-depleted oocytes, higher percentage of chromosome misalignment was observed and more oocytes overrode the M I stage arrest induced by low concentration of nocodazole. Our data suggest that BubR1 is a spindle assembly checkpoint protein regulating meiotic progression of oocytes.

Perturbation of survivin expression affects chromosome alignment and spindle checkpoint in mouse oocyte meiotic maturation

Survivin is a member of inhibitors of apoptosis proteins (IAPs), which have multiple regulatory functions in mitosis, but its roles in meiosis remain unknown. Here, we report its expression, localization and functions in mouse oocyte meiosis. Survivin displayed a maximal expression level in GV stage, and then gradually decreased from Pro-MI to MII stages. Immunofluorescent staining showed that survivin was restricted to the germinal vesicle, associated with centromeres from pro-metaphase I to metaphase I stages, distributed at the midzone and midbody of anaphase and telophase spindles, and located to centromeres at metaphase II stages. Depletion of survivin by antibody injection and morpholino injection resulted in severe chromosome misalignment, precocious polar body extrusion, and larger-than-normal polar bodies. Overexpression of survivin resulted in severe chromosome misalignment and prometaphase I or metaphase I arrest in a large proportion of oocytes. Our data suggest that survivin is required for chromosome alignment and that it may regulate spindle checkpoint activity during mouse oocyte meiosis.

Demethylation of LHR in dehydroepiandrosterone-induced mouse model of polycystic ovary syndrome

The cause of polycystic ovary syndrome (PCOS), a complex endocrine disorder, is unknown, but its familial aggregation implies underlying genetic influences. Hyperandrogenemia is regarded as a major endocrine character of the PCOS. In this study, we employed bisulfite sequencing and bisulfite restriction analysis to investigate the DNA methylation status of LHR, AR, FSHR and H19 in dehydroepiandrosterone (DHEA)-induced mouse PCOS model. The result showed that methylation of LHR was lost in ovary from induced PCOS mouse. However, AR, FSHR and H19 had similar methylation pattern in DHEA-treated group and control groups. These data provide evidence for close linkage between DNA demethylation of LHR and PCOS.

A novel variant of ER-alpha, ER-alpha36 mediates testosterone-stimulated ERK and Akt activation in endometrial cancer Hec1A cells

BACKGROUND

Endometrial cancer is one of the most common gynecologic malignancies and its incidence has recently increased. Experimental and epidemiological data support that testosterone plays an important role in the pathogenesis of endometrial cancer, but the underlying mechanism has not been fully understood. Recently, we identified and cloned a variant of estrogen receptor (ER) alpha, ER-alpha36. The aim of the present study was to investigate the role of ER-alpha36 in testosterone carcinogenesis.

METHODS

The cellular localization of ER-alpha36 was determined by immunofluorescence. Hec1A endometrial cancer cells (Hec1A/V) and Hec1A cells with siRNA knockdown of ER-alpha36 (Hec1A/RNAi) were treated with testosterone, ERK and Akt phosphorylation was assessed by Western blot analysis. Furthermore, the kinase inhibitors U0126 and LY294002 and the aromatase inhibitor letrozole were used to elucidate the pathway underlying testosterone-induced activities.

RESULTS

Immunofluorescence shows that ER-alpha36 was localized on the plasma membrane of the both ER-alpha- and androgen receptor-negative endometrial cancer Hec1A cells. Testosterone induced ERK and Akt phosphorylation, which could be abrogated by ER-alpha 36 shRNA knockdown or the kinase inhibitors, U0126 and LY294002, and the aromatase inhibitor letrozole.

CONCLUSION

Testosterone induces ERK and Akt phosphorylation via the membrane-initiated signaling pathways mediated by ER-alpha36, suggesting a possible involvement of ER-alpha 36 in testosterone carcinogenesis.

Heat stress causes aberrant DNA methylation of H19 and Igf-2r in mouse blastocysts

To gain a better understanding of the methylation imprinting changes associated with heat stress in early development, we used bisulfite sequencing and bisulfite restriction analysis to examine the DNA methylation status of imprinted genes in early embryos (blastocysts). The paternal imprinted genes, H19 and Igf-2r, had lower methylation levels in heat-stressed embryos than in control embryos, whereas the maternal imprinted genes, Peg3 and Peg1, had similar methylation pattern in heat-stressed embryos and in control embryos. Our results indicate that heat stress may induce aberrant methylation imprinting, which results in developmental failure of mouse embryos, and that the effects of heat shock on methylation imprinting may be gene-specific.

Diploid parthenogenetic embryos adopt a maternal-type methylation pattern on both sets of maternal chromosomes

Epigenetic modifications are closely associated with embryo developmental potential. One of the epigenetic modifications thought to be involved in genomic imprinting is DNA methylation. Here we show that the maternally imprinted genes Snrpn and Peg1/Mest were nearly unmethylated or heavily methylated, respectively, in their differentially methylated regions (DMRs) at the two-cell stage in parthenogenetic embryos. However, both genes were gradually de novo methylated, with almost complete methylation of all CpG sites by the morula stage in parthenogenetic embryos. Unexpectedly, another maternally imprinted gene, Peg3, showed distinct dynamics of methylation during preimplantation development of diploid parthenogenetic embryos. Peg3 showed seemingly normal methylation patterns at the two-cell and morula stages, but was also strongly de novo methylated in parthenogenetic blastocysts. In contrast, the paternally imprinted genes H19 and Rasgrf1 showed complete unmethylation of their DMRs at the morula stage in parthenogenetic embryos. These results indicate that diploid parthenogenetic embryos adopt a maternal-type methylation pattern on both sets of maternal chromosomes and that the aberrantly homogeneous status of methylation imprints may partially account for developmental failure.

Birth of twins after in vitro fertilization with flow-cytometric sorted buffalo (Bubalus bubalis) sperm

Flow-cytometric sorting of mammalian sperm for production of offspring with the desired sex is one of the most important new biotechnologies available for livestock industry. The objectives of this study were: (i) to sort the sperm into X- and Y-enriched populations and (ii) use the sorted sperm for in vitro fertilization (IVF) to produce sex-preselected embryo and offspring. The results revealed that the accuracy of sorted X- and Y-sperm was 94% and 89%, respectively. There was a decrease in blastocyst development rate in IVF with sorted sperm comparing to unsorted sperm, but the percentage of blastocysts on D6-D8 was not statistically different. Transplantation of the presumed X-embryos derived from IVF into a recipient resulted in the birth of female twins. These results indicated the feasibility of sperm sorting by flow cytometry and in vitro production of sex-preselected embryos and offspring in buffalo.

Safety and efficacy of percutaneous injection of polyurethane elastomer (MPU) plugs for vas occlusion in man

This report describes the safety and efficacy of the procedure for percutaneous injection of medical-grade polyurethane elastomer (MPU) to form plugs in the vas deferens. The injection of 0.16-0.22 ml MPU in 53 men resulted in occlusion and azoospermia in 85% of the men after 12 months; 96% achieved azoospermia by 2 years. The success rate of the method and the rate of sperm suppression to azoospermia depended on the shapes of the plugs; this was determined by palpation after insertion. There were few complications and the results are discussed in terms of the reversibility potential of this method.

Developmental and environmental regulation of a phenylalanine ammonia-lyase-beta-glucuronidase gene fusion in transgenic tobacco plants

A 1.1-kilobase promoter fragment of the bean (Phaseolus vulgaris L.) phenylalanine ammonia-lyase (EC 4.3.1.5) gene PAL2 was translationally fused to the beta-glucuronidase reporter gene and transferred to tobacco by Agrobacterium tumefaciens-mediated leaf disk transformation. The distribution of beta-glucuronidase activity in these transgenic plants is very similar to that of endogenous PAL2 transcripts in bean, with very high levels in petals; marked accumulation in anthers, stigmas, roots, and shoots; and low levels in sepals, ovaries, and leaves. Histochemical analysis of the spatial pattern of beta-glucuronidase activity showed that the PAL2 promoter is highly active in the shoot apical meristem, the zone of cell proliferation immediately adjacent to the root apical meristem, and in the early stages of vascular development at the inception of xylem differentiation. Wounding and light evoke specific changes in the spatial pattern of beta-glucuronidase activity in stems, including induction in the epidermis. These data indicate that the PAL2 promoter transduces a complex set of developmental and environmental cues into an integrated spatial and temporal program of gene expression to regulate the synthesis of a diverse array of phenylpropanoid natural products.

Differential regulation of phenylalanine ammonia-lyase genes during plant development and by environmental cues

Phenylalanine ammonia-lyase (PAL) catalyzes the first reaction in the biosynthesis from phenylalanine of a wide variety of phenylpropanoid natural products including lignin, flavonoid pigments, and phytoalexins. In bean (Phaseolus vulgaris L.), PAL is encoded by a family of three genes. We show here by RNase protection with gene-specific probes that these genes are expressed differentially during development and in response to different environmental cues. While all three genes are expressed at high levels in roots, only PAL1 and PAL2 are expressed in shoots and only PAL1 is expressed in leaves. Strikingly, PAL2 is expressed at very high levels in petals, where PAL1 is only very weakly expressed and PAL3 is not expressed. All three genes are induced by mechanical wounding of hypocotyls, but fungal infection only activates PAL1 and PAL3. Illumination of etiolated hypocotyls activates PAL1 and PAL2 but not PAL3. Corresponding differential patterns of synthesis of specific PAL polypeptide isoforms were observed by two-dimensional gel electrophoretic analysis of in vitro translation products encoded by RNA isolated from hypocotyls stimulated by light, wounding, or infection. The specific isoforms encoded by transcripts of the three PAL genes were identified by inhibition of synthesis in vitro with gene-specific anti-sense transcripts followed by comparative two-dimensional gel electrophoretic analysis of the pattern of translation products. These data indicate that selective expression of PAL genes encoding functional variants is governed by a complex set of regulatory networks for developmental and environmental control of phenylpropanoid biosynthesis.

Organization and differential activation of a gene family encoding the plant defense enzyme chalcone synthase in Phaseolus vulgaris

Chalcone synthase (CHS) catalyzes the first and key regulatory step in the branch pathway of phenylpropanoid biosynthesis specific for synthesis of ubiquitous flavonoid pigments and UV protectants. In bean (Phaseolus vulgaris L.) and other members of the Leguminoseae, chalcone synthase is also involved in the synthesis of the isoflavonoid-derived phytoalexin antibiotics characteristic of this family. We have demonstrated that the haploid genome of bean contains a family of about six to eight CHS genes, some of which are tightly clustered. Treatment of bean cells with fungal elicitor activates several of these genes leading to the accumulation of at least five and probably as many as nine distinct CHS transcripts encoding a set of CHS isopolypeptides of Mr 42-43 kDa but with differing pI in the range pH 6-7. In elicited cells specific transcripts and encoded polypeptides are differentially induced with respect to both the extent and kinetics of accumulation. Wounding or infection of hypocotyl tissue also activates several CHS genes with marked differences in the pattern of accumulation of specific transcripts and encoded polypeptides in wounded compared to infected tissue or elicited cells, indicating operation of more than one cue for defense gene activation. Illumination induces accumulation of a different set of CHS transcripts including only one of the set hitherto demonstrated to be induced by biological stress. The organization and differential regulation of the CHS gene family in bean are discussed in relation to the functions of this enzyme in adaptative and protective responses to diverse environmental stresses.

Plasmids related to the broad host range vector, pRK290, useful for gene cloning and for monitoring gene expression

Derivatives of plasmid pRK290 that are useful for cloning and for analyzing gene expression in a wide variety of Gram-negative bacteria are described. A smaller broad host range plasmid derived from RK2, with properties similar to that of pRK290, is also described.