Development of interspecies cloned monkey embryos reconstructed with bovine enucleated oocytes

This study was carried out to determine whether culture media reconstructed with bovine enucleated oocytes and the expression pattern of Oct-4 could support dedifferentiaton of monkey fibroblasts in interspecies cloned monkey embryos. In this study, monkey and bovine skin fibroblasts were used as donor cells for reconstruction with bovine enucleated oocytes. The reconstructed monkey interspecies somatic cell nuclear transfer (iSCNT) embryos were then cultured under six different culture conditions with modifications of the embryo culture media and normal bovine and monkey specifications. The Oct-4 expression patterns of the embryos were examined at the two-cell to blastocyst stages using immunocytochemistry. The monkey iSCNT embryos showed similar cleavage rates to those of bovine SCNT and bovine parthenogenetic activation (PA). However, the monkey iSCNT embryos were not able to develop beyond the 16-cell stage under any of the culture conditions. In monkey and bovine SCNT embryos, Oct-4 could be detected from the two-cell to blastocyst stage, and in bovine PA embryos, Oct-4 was detectable from the morula to blastocyst stage. These results suggested that bovine ooplasm could support dedifferentiation of monkey somatic cell nuclei but could not support embryo development to either the compact morula or blastocyst stage. In conclusion, we found that the culture conditions that tend to enhance monkey iSCNT embryo development and the expression pattern of Oct-4 in cloned embryos (monkey iSCNT and bovine SCNT) are different than in bovine PA embryos.     

Estriolum Treatment in the Bitch: A Risk for Uterine Infection?

Purulent vaginal discharge in a bitch in which ovariohysterectomy has been performed is often caused by inflammation of the uterine stump. The inflammation is due to either cystic endometrial hyperplasia (CEH) induced primarily by progesterone from remnant ovarian tissue or exogenous progestagens, or it is due to the presence of unabsorbed suture material. This report describes a 9-year-old Irish setter with hemopurulent vaginal discharge and non-pruritic symmetrical alopecia, which had undergone ovariohysterectomy 3.5 years ago and which had been treated with estriolum daily for the past 2.5 years because of urinary incontinence. Vaginoscopy revealed hemopurulent discharge throughout the vagina and vestibule. Cytological examination of ultrasound-guided fine-needle aspiration biopsies of a large mass in the hypogastricum, which appeared to be the uterine cervical stump, revealed septic purulent inflammation. The concentration of plasma progesterone was low and the concentration of plasma 17-ß oestradiol did not increase after gonadotrophin-releasing hormone administration. No remnant ovarian tissue was found by abdominal ultrasonography, laparotomy, or histological examination of mesovarian pedicles. Laparotomy revealed uterine stump empyema. Histological examination of the surgically removed mass excluded both CEH and unabsorbed suture material as the cause of the stump empyema. Instead, it is hypothesized that the long-term treatment with estriolum was a causative factor. This suggests that bitches treated with estriolum should be examined regularly.     

Concurrent immune-mediated haemolytic anaemia and severe thrombocytopenia in 21 dogs

The medical records of 21 dogs with concurrent immune-mediated haemolytic anaemia (imha) and severe thrombocytopenia (defined as an automated platelet count of less than 50x10(9)/l, confirmed by the examination of a blood smear) were reviewed. Their mean (sd) age was 5.8 (2.5) years. When compared with the 24,759 dogs in the hospital population for the same period Airedale terriers and dobermanns appeared to be over-represented with odds ratios of 22.5 (95 per cent confidence interval [ci] 5.2 to 97.9) and 7.6 (95 per cent ci 1.8 to 32.7) respectively. The median duration of the dogs' clinical signs was seven days, with a range from one to 17 days. Eleven of the dogs had a history of a tendency to bleed, and 15 had evidence of bleeding when examined. Twenty of the 21 dogs had been treated with glucocorticoids, nine with vincristine, and seven with azathioprine. Their median stay in hospital was four days, with a range from one to 17 days. The median period for which they survived after admission to hospital was five days, with a range from one to 558 days, and 16 of the 21 dogs had died or been euthanased within 30 days of their admission.     

Seroepidemiology and genotyping of hepatitis E virus in Singapore reveal rise in number of cases and similarity of human strains to those detected in pig livers

Hepatitis E virus (HEV) causes 20 million infections worldwide yearly, of which only about 3.3 million are symptomatic. In developed Asian countries, HEV strains detected in human sera and in food sources were genetically similar, suggesting that indigenous HEV infections may be largely food‐borne. To assess the burden of hepatitis E in Singapore, we performed a seroepidemiologic study of the infection. Additionally, we carried out HEV genotyping on archived, residual HEV IgM‐positive serum samples collected between 2014 and 2016 (n = 449), and on pig liver samples (n = 36) purchased from wet markets and supermarkets. Our study shows a rise in hepatitis E incidence (IgM) from 1.7 to 4.1 cases per 100,000 resident population from 2012 to 2016 and an increase in hepatitis E IgG positivity rate among residents from 14% in 2007 to 35% in 2016. Other findings also suggest the epidemiology of hepatitis E in Singapore has shifted, from it being mainly a disease imported from the Indian subcontinent, to one that is now increasingly prevalent in our resident population. Genotypes obtained from 143 human samples identified the majority to be genotype 3 (n = 121), 21 to be genotype 1 and one to be genotype 4. Further phylogenetic analyses suggest genotype 3a to be the cause of indigenous infections in residents, which showed genetic similarity to the genotype 3a strains detected in pig livers. This link between the strains in the majority of human samples and those in pig livers consumed by the public suggests a possible food‐borne route of HEV infection in Singapore.     

Biofilm production by pathogens associated with canine otitis externa,and the antibiofilm activity of ionophores and antimicrobial adjuvants

Otitis externa (OE) is a frequently reported disorder in dogs associated with secondary infections by Staphylococcus, Pseudomonas and yeast pathogens. The presence of biofilms may play an important role in the resistance of otic pathogens to antimicrobial agents. Biofilm production of twenty Staphylococcus pseudintermedius and twenty Pseudomonas aeruginosa canine otic isolates was determined quantitatively using a microtiter plate assay, and each isolate was classified as a strong, moderate, weak or nonbiofilm producer. Minimum biofilm eradication concentration (MBEC) of two ionophores (narasin and monensin) and three adjuvants (N‐acetylcysteine (NAC), Tris‐EDTA and disodium EDTA) were investigated spectrophotometrically (OD_570nm) and quantitatively (CFU/ml) against selected Staphylococcus and Pseudomonas biofilm cultures. Concurrently, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of planktonic cultures were assessed. 16/20 of the S. pseudintermedius clinical isolates were weak biofilm producers. 19/20 P. aeruginosa clinical isolates produced biofilms and were distributed almost equally as weak, moderate and strong biofilm producers. While significant antibiofilm activity was observed, no MBEC was achieved with narasin or monensin. The MBEC for NAC ranged from 5,000–10,000 µg/ml and from 20,000–80,000 µg/ml against S. pseudintermedius and P. aeruginosa, respectively. Tris‐EDTA eradicated P. aeruginosa biofilms at concentrations ranging from 6,000/1,900 to 12,000/3,800 µg/ml. The MBEC was up to 16‐fold and eightfold higher than the MIC/MBC of NAC and Tris‐EDTA, respectively. Disodium EDTA reduced biofilm growth of both strains at concentrations of 470 µg/ml and higher. It can be concluded that biofilm production is common in pathogens associated with canine OE. NAC and Tris‐EDTA are effective antibiofilm agents in vitro that could be considered for the treatment of biofilm‐associated OE in dogs.     

Mechanism of AKT1 negatively regulating breast cancer cell migration

AIM: To investigate the molecular mechanism and downstream signaling pathway by which AKT1 inhibition regulates breast cancer cell migration. METHODS: RNA interference was used to knockdown the expression of AKT1. Western blot assay was performed to examine the expression of AKT1 total protein, β-catenin total protein and β-catenin nuclear protein. Immunofluorescence was used to examine the cellular localization of β-catenin. Transwell assay was used to investigate whether β-catenin nuclear accumulation as an alternative pathway was responsible for breast cancer metastasis induced by AKT1 inhibition. RESULTS: The total protein expression of AKT1 was decreased in MCF-7 and MDA-MB-231 cells treated with AKT1 siRNA. A significant increase in the protein expression of β-catenin was observed in MCF-7 cells and MDA-MB-231 cells treated with AKT1 siRNA. Immunofluorescence staining showed that MCF-7 cells and MDA-MB-231 cells displayed strong β-catenin staining in the cytoplasm and nucleus after knockdown of AKT1 expression. The ability of tumor cell migration increased dramatically after treated with AKT1 specific siRNA in the breast cancer MCF-7 cells and MDA-MB-231 cells in Transwell assay. XAV-939 reversed breast cancer cell migration induced by knockdown of AKT1 expression. CONCLUSION: β-catenin nuclear accumulation contributes to AKT1 inhibition-mediated breast cancer cell migration.     

Effects of Landfill Gas on Growth and Nitrogen Fixation of Two Leguminous Trees (Acacia Confusa,Leucaena Leucocephala)

A study was made on the effects of landfill gas on ARA (acetylene reducing activity) of nodules of two woody legumes (Acacia confusa and Leucaena leucocephala) widespread on landfill sites in Hong Kong. The effects of the three main components of landfill gas, O₂, CO₂ and CH4, were first measured separately over a 1-hr period. Maximum ARA was found at 20% O₂ (close to atmospheric partial pressure) and ARA decreased as the O₂ decreased in the range of 16–1%. Acacia confusa nodular ARA was significantly inhibited at 30–50% CO₂, but not Leucaena leucocephala nodular ARA. CH₄ had no significant effect on ARA of either species. As the landfill gas concentrations in the landfill topsoil were mostly > 10% O₂ and < 10% CO₂, root nodules should fix N₂ effectively over these ranges of gases. A four-week test was conducted to assess the long-term influence of landfill gas on seedlings of the two legumes. Landfill gas and elevated CO₂ both suppressed their growth and their nodular ARA. Even under the influence of the gases, however, seedlings with nodules formed a higher biomass than seedlings lacking nodules. The growth of the two legumes under actual landfill conditions was investigated by transplanting non-inoculated and pre-inoculated seedlings to two landfill sites in Hong Kong: Junk Bay and Shuen Wan Landfill. After six months, most of the non-inoculated seedlings became infected: Acacia confusa 63 and 70%, Leucaena leucocephala 17 and 89%, respectively, at the test sites. The results indicate that there were free rhizobia at these landfill sites to infect the legumes and they had formed effective nodules to fix N₂ under landfill conditions.     

应用PAPD方法对鸡败血霉形体DNA多态性的研究

用随机扩增多态性ＤＮＡ（ＲＡＰＤ）方法,通过筛选的５个随机引物（ＯＰＨ－０２,ＯＰＨ－０５,ＯＰＨ－０７,ＯＰＨ－１３,ＯＰＧ－１６）,对１４株鸡败血霉形体（ＭＧ）国际标准株和国内分离株进行了ＤＮＡ多态性研究。结果表明,５个引物共产生２１种条带,其中有３个条带分别为２个菌株所特有,扩增产物片段的长度在１５０～４５００ｂｐ之间,所有菌株均有１条共同条带,以ＯＰＨ－０５扩增产物的多态性最丰富。根据样品ＤＮＡ所获得的菌株间相似性指数表明,Ｄ９６０３与Ｄ９６０７相似指数最高,Ｓ６,Ｋ３９１３和Ｄ９６０４三者相互间相似性指数最低。提示ＲＡＰＤ方法可用于霉形体遗传标记的分析。     

美味黑粉菌冬孢子萌发条件的研究

研究了疏亲水界面、温度、pH值和不同物质对美味黑粉菌冬孢子萌发的影响,以探讨美味黑粉菌冬孢子在自然生境条件萌发的适应性。研究结果表明,疏水界面促进美味黑粉菌冬孢子萌发,在疏水的聚苯乙烯塑料培养皿和茭白茎表皮上,萌发率高;冬孢子萌发的最适温度为27～30℃,温度过高或过低均抑制萌发;酸性条件促进冬孢子萌发,最适pH值为3～4;蔗糖促进冬孢子萌发,且以1%浓度最适,但同样浓度的甘露醇、葡萄糖、海藻糖、D-果糖等抑制冬孢子萌发。     

多年生人工牧草“老芒麦”根系层土壤含水率对节水的影响研究

基于浑善达克沙地人工牧草灌溉试验场观测的气象、叶片的蒸腾速率、叶面积指数、有效根系层深度、土壤含水率、土壤蒸发等数据,利用双作物系数法模拟计算了2004、2005年老芒麦的日作物需水量,经与实测的作物蒸腾和土壤蒸发数据对比分析,检验了需水量模拟值与实测值间的一致性,在此基础之上,讨论了老芒麦需水量与产量、光合作用与蒸腾速率、光合作用与根系层土壤含水率的关系,结果表明:对老芒麦来说,从抑制无效蒸腾角度实现节水最直接的方法应该是有效根系层的土壤水分保持在田间持水率的51%~74%。