A baseline epidemiological study of the co-infection of enteric protozoans with human immunodeficiency virus among men who have sex with men from Northeast China

BackgroundHuman immunodeficiency virus (HIV) and enteric parasite co-infection not only aggravates the clinical symptoms of parasites but also accelerates acquired immunodeficiency syndrome (AIDS) progression. However, co-infection research on men who have sex with men (MSM), the predominant high-risk population of HIV/AIDS in China, is still limited. In this study, we investigated the epidemiology of enteric parasites, risk factors, and associations with clinical significance in an MSM HIV/AIDS population in Heilongjiang Province, northeast China.MethodsWe recruited 308 MSMs HIV/AIDS patients and 199 HIV-negative individuals in two designated AIDS hospitals in Heilongjiang between April 2016 and July 2017. Fresh stool samples were collected. DNA extraction, molecular identification, and genotyping of Cryptosporidium species, Entamoeba histolytica, Cyclospora cayetanensis, Enterocytozoon bieneusi, and Blastocystis hominis were performed. Fourteen diarrhea-related pathogens were examined to exclude the influence of other bacterial pathogens on diarrhea incidence.Results31.5% of MSM HIV/AIDS participants were infected with at least one parasite species, a significantly higher proportion than that found in the HIV-negative individuals (2.5%). E. bieneusi presented the highest prevalence, followed by B. hominis, E. histolytica, Cryptosporidium spp., and C. cayetanensis. Warm seasons were the risk factor for parasitic infections in this population [odds ratio (OR) = 2.6, 95% CI: 1.47–4.57]. In addition, these individuals showed a higher proportion (35.8%) of present diarrhea (PD) compared with men who have sex with women (MSW) with HIV/AIDS (16.7%). The infection proportions of both Cryptosporidium spp. and E. histolytica were significantly higher in the PD. E. bieneusi infection was more prevalent in the historic diarrhea (HD) group. CD4⁺ T cell counts in the MSM patients with the above three parasites were significantly lower. New species and genotypes were found, and MSM patients had a wider range of species or genotypes.ConclusionsEnteric parasitic infection was prevalent in the MSM HIV/AIDS population, especially in patients with present diarrhea during warm seasons. E. histolytica and B. hominis should also be considered high-risk parasites for opportunistic infections in AIDS patients in addition to Cryptosporidium spp.     

中国野生动物调查存在的问题与改进建议

一百余年前,人类就开始了相对系统的野生动物调查。目前已经建立了成熟的方法体系,并制定了相应的调查规范。最近几十年来,我国科研人员进行了大量的野生动物调查。但是,当前我国的野外调查规范还不够细致,调查者在调查时缺乏必要的约束,导致调查数据不规范、不可靠,很多重要信息缺失。突出问题有：样线信息不全,只有起点和终点的经纬度,没有自动记录的详细样线信息（如每秒记录一次的连续点位信息,含经纬度和时间）;动物位点信息缺乏可信度指标（如距观测者的距离）;调查时间不合理;调查地点的空间取样不均衡;记录的标准化不够（如每个观测点的观测时长不确定）等等。对此,我们参考国际通用的调查规范,提出了一些简单易行的调查要点,以便提高野外调查数据的质量。另外,我们提倡野外记录的无纸化,充分利用现有的手机应用软件（APP）和模型工具提高野外记录以及后期数据处理的效率。最后,我们提议建立固定的中国生物多样性监测样线体系,以便消除每年调查时空间取样的不确定性,更好地量化野生动物的时间动态,为野生动物的保护和管理提供依据。     

南亚热带水土流失地区人工加速植被演替过程

水土流失地区植被在自然条件下从阳生草本到乔灌草复合植被的演替过程常常需要很长的时间,选取适当树种人工造林可以省略先锋物种强阳生草本的发育时间,提早诱发灌木和草本植物发育,大大加速植被恢复演替过程。通过对广东惠州市惠阳区上杨试验站等南亚热带典型水土流失地区的研究发现：自然封育状态下,水土流失地区植被恢复和演替缓慢,25。后植被覆盖度只有35％,且主要以阳生性耐贫瘠的灌木及草本为主,土壤侵蚀仍然比较严重。选择大叶相思树人工造林加速了植被演替进程,控制了水土流失,12a左右植被覆盖度就达90％左右。造林23a左右,林地遮蔽涵养水分和控制侵蚀作用下迅速生长多种当地物种,形成了乔、灌、草、藤、竹多层复合植被。在南亚热带季风气候地区,自然封育状态下严重水土流失区植被恢复至较稳定的次生林阶段需要60a左右的时间;人工造林加速植被演替只需要20a。植树造林是该地区植被恢复发育及控制水土流失的有效措施。     

融合表达氨基转移酶DsaD和异构酶DsaE合成L-别异亮氨酸

【背景】L-异亮氨酸(L-isoleucine,L-Ile)和L-别异亮氨酸(L-allo-isoleucine,L-allo-Ile)是自然界中广泛存在的一对同分异构体。抗感染抗生素Desotamides结构中含L-别异亮氨酸结构单元,其生物合成途径中的氨基转移酶DsaD和异构酶DsaE可以协作催化L-异亮氨酸和L-别异亮氨酸相互转化。【目的】通过理性设计,使氨基转移酶DsaD和异构酶DsaE融合表达,研究融合蛋白DsaDE催化异亮氨酸和别异亮氨酸相互转化的功能。【方法】利用PCR分别扩增dsaE基因编码区DNA片段、以及含dsaD基因编码区和114个碱基接头序列的DNA片段dsaD-linker,利用酶切位点KpnI将dsaE和dsaD-linker相连,形成das DE重组序列,并克隆至pET28a(+)中,将重组质粒pET28a-dsaDE转化至Escherichia coli BL21(DE3)中进行融合表达,利用Ni-NTA亲和层析法纯化融合蛋白DsaDE;分别以L-异亮氨酸和L-别异亮氨酸为底物进行融合蛋白的体外酶活性检测,利用高效液相色谱对酶反应产物进行分析。【结果】PCR验证、酶切验证以及测序结果证明pET28a-dsaDE重组载体具有正确序列;N-末端和C-末端融合6个组氨酸标签的融合蛋白DsaDE在E. coli BL21(DE3)中获得可溶性表达,经Ni-NTA亲和层析法一步纯化获得纯度约95%的融合蛋白,纯化的融合蛋白DsaDE具有较好的活性,能够催化L-isoleucine和L-allo-isoleucine间的相互转化。【结论】氨基转移酶DsaD和异构酶DsaE成功融合表达,经一步Ni-NTA亲和层析法纯化即可获得纯度较高的融合蛋白,融合蛋白同时具有氨基转移酶和异构酶的活性,为进一步研究L-别异亮氨酸的工业化生产奠定了基础。     

Ginsenoside Rh2 mitigates doxorubicin‐induced cardiotoxicity by inhibiting apoptotic and inflammatory damage and weakening pathological remodelling in breast cancer‐bearing mice

ObjectivesThere are presently a few viable ways to reduce cardiotoxicity of doxorubicin (Dox). The combination of chemotherapy agents with natural compounds delivers greater efficacy and reduces adverse effects in recent researches for cancer treatment. Here, we examined the potential effect of ginsenoside Rh2 on a Dox‐based regimen in chemotherapy treatment.Materials and MethodsHuman breast tumour (MDA‐MB‐231) xenograft nude mice, human cardiac ventricle fibroblasts, and human umbilical vein endothelial cells (HUVEC) were employed in the present study. Histology, immunohistochemistry, immunofluorescence, western blot, antibody array, and RNA‐sequencing analyses were utilized to assess the protective effect of Rh2 on cardiotoxicity induced by Dox and the underlying mechanisms.ResultsRh2‐reduced cardiotoxicity by inhibiting the cardiac histopathological changes, apoptosis and necrosis, and consequent inflammation. Pathological remodelling was attenuated by reducing fibroblast to myofibroblast transition (FMT) and endothelial–mesenchymal transition (EndMT) in hearts. RNA‐sequencing analysis showed that Dox treatment predominantly targets cell cycle and attachment of microtubules and boosted tumour necrosis, chemokine and interferon‐gamma production, response to cytokine and chemokine, and T cell activation, whereas Rh2 regulated these effects. Intriguingly, Rh2 also attenuated fibrosis via promoting senescence in myofibroblasts and reversing established myofibroblast differentiation in EndMT.ConclusionsRh2 regulates multiple pathways in the Dox‐provoked heart, proposing a potential candidate for cancer supplement and therapy‐associated cardiotoxicity.

Doxorubicin is extensively reported to induce severe cardiotoxicity in clinical applications. Our work proposed a natural herbal compound, ginsenoside Rh2, as a potential candidate for attenuating this side effect. Rh2 significantly inhibited cardiac apoptosis and necrosis, inflammation, and pathological remodelling in Dox‐challenged hearts.     

泥河湾盆地三棵树遗址ESR年代学

泥河湾盆地因发育良好的晚新生代湖相地层、丰富的旧石器遗址和哺乳动物化石而广受关注.盆地内已发现旧石器遗址100余处,被学术界称为"东方奥杜韦(Olduvai)峡谷".由于缺乏合适的年代测定方法,许多重要的遗址,尤其是中更新世时间段的遗址缺乏年龄数据,如三棵树遗址,使得旧石器遗址研究少了时间轴合理的年代学框架.电子自旋共...     

Ungulate bocaparvovirus 4 and rodent bocavirus are different genotypes of the same species of virus

Bocaviruses are associated with many human infectious diseases, such as respiratory tract infections, gastroenteritis, and hepatitis. Rats are known to be reservoirs of bocaviruses, including rodent bocavirus and rat bocavirus. Recently, ungulate bocaparvovirus 4, a known porcine bocavirus, has also been found in rats. Thus, investigating bocaviruses in rats is important for determining the origin of the viruses and preventing and controlling their transmission. To the best of our knowledge, no study to date has investigated bocaviruses in the livers of rats. In this report, a total of 624 rats were trapped in southern China between 2014 and 2017. Liver and serum samples from rats were tested for the prevalence of bocaviruses using PCR. Sequences related to ungulate bocaparvovirus 4 and rodent bocavirus were detected in both liver and serum samples. Interestingly, the prevalence of ungulate bocaparvovirus 4 (reference strain:KJ622366.1) was higher than that of rodent bocavirus (reference strain:KY927868.1) in both liver (2.24% and 0.64%, respectively) and serum samples (2.19% and 0.44%, respectively). The NS1 regions of ungulate bocaparvovirus 4 and rodent bocavirus related sequences displayed over 84% and 88% identity at the nucleic acid and amino acid levels, respectively. Furthermore, these sequences had similar genomic structure, genomic features, and codon usage bias, and shared a common ancestor. These viruses also displayed greater adaptability to rats than pigs. Our results suggested that ungulate bocaparvovirus 4 and rodent bocavirus may originate from rats and may be different genotypes of the same bocavirus species.     

Efficient assembly of a large fragment of monkeypox virus genome as a qPCR template using dual-selection based transformation-associated recombination

Transformation-associated recombination (TAR) has been widely used to assemble large DNA constructs. One of the significant obstacles hindering assembly efficiency is the presence of error-prone DNA repair pathways in yeast, which results in vector backbone recircularization or illegitimate recombination products. To increase TAR assembly efficiency, we prepared a dual-selective TAR vector, pGFCS, by adding a P_ADH1-URA3 cassette to a previously described yeast-bacteria shuttle vector, pGF, harboring a P_HIS3-HIS3 cassette as a positive selection marker. This new cassette works as a negative selection marker to ensure that yeast harboring a recircularized vector cannot propagate in the presence of 5-fluoroorotic acid. To prevent pGFCS bearing ura3 from recombining with endogenous ura3-52 in the yeast genome, a highly transformable Saccharomyces cerevisiae strain, VL6-48B, was prepared by chromosomal substitution of ura3-52 with a transgene conferring resistance to blasticidin. A 55-kb genomic fragment of monkeypox virus encompassing primary detection targets for quantitative PCR was assembled by TAR using pGFCS in VL6-48B. The pGFCS-mediated TAR assembly showed a zero rate of vector recircularization and an average correct assembly yield of 79% indicating that the dual-selection strategy provides an efficient approach to optimizing TAR assembly.