Real Time Measures of Prestin Charge and Fluorescence during Plasma Membrane Trafficking Reveal Sub-Tetrameric Activity

Prestin (SLC26a5) is the outer hair cell integral membrane motor protein that drives cochlear amplification, and has been described as an obligate tetramer. We studied in real time the delivery of YFP-prestin to the plasma membrane of cells from a tetracycline-inducible cell line. Following the release of temperature block to reinstate trans Golgi network delivery of the integral membrane protein, we measured nonlinear capacitance (NLC) and membrane fluorescence during voltage clamp. Prestin was delivered exponentially to the plasma membrane with a time constant of less than 10 minutes, with both electrical and fluorescence methods showing high temporal correlation. However, based on disparity between estimates of prestin density derived from either fluorescence or NLC, we conclude that sub-tetrameric forms of prestin contribute to our electrical and fluorescence measures. Thus, in agreement with previous observations we find that functional prestin is not an obligate tetramer.     

Upregulation of miR-183 represses neuropathic pain through inhibiton of MAP3K4 in CCI rat models

Many studies have verified that microRNAs contribute a lot to neuropathic pain progression. Furthermore, nerve-related inflammatory cytokines play vital roles in neuropathic pain progression. miR-183 has been identified to have a common relationship with multiple pathological diseases. However, the potential effects of miR-183 in the process of neuropathic pain remain undetermined. Therefore, we performed the current study with the purpose of finding the functions of miR-183 in neuropathic pain progression using a chronic sciatic nerve injury (CCI) rat model. We demonstrated that miR-183 expression levels were evidently reduced in CCI rats in contrast with the control group. Overexpression of miR-183 produced significant relief of mechanical hyperalgesia, as well as thermal hyperalgesia in CCI rats. Furthermore, neuropathic pain-correlated inflammatory cytokine expression levels containing interleukin-6 (IL-6) and interleukin-1β (IL-1β), cyclooxygenase-2 (COX-2) were obviously inhibited by upregulation of miR-183. Meanwhile, dual-luciferase reporter assays showed MAP3K4 was a direct downstream gene of miR-183. The expression levels of MAP3K4 were modulated by the increased miR-183 negatively, which lead to the downregulation of IL-6, IL-1β, and COX-2, and then reduced neuropathic pain progression, respectively. Overall, our study pointed out that miR-183 was a part of the negative regulator which could relieve neuropathic pain by targeting MAP3K4. Thus it may provide a new clinical treatment for neuropathic pain patients clinical therapy.     

主养青鱼池塘生态系统能量转换率的研究

1985—1987年对苏州市郊区主养青鱼池塘生态系统的能量转换率进行了分析。结果表明,主养青鱼净产7.5、11.25、15t/ha 3个产量级型池塘青鲤团头鲂产出能占养鱼总产出能的比例分别为82.49、78.03、79.34％;总投入能(太阳辐射能+辅助能)转移到鱼的总产出能转换率分别为0.19、0.24、0.31％;太阳辐射能转移到毛和净初级生产力的能量转换率分别为0.76、0.90、0.96％和0.61、0.72、0.77％;净初级生产力转移到滤食性鱼净产量的能量转换率分别为4.02、4.63、5.27％;辅助能转移到鱼净产量的能量转换率分别为12.20、11.33。11.74％。在3个产量级型池塘中,以15t/ha产量级的能量转换率为最佳型。     

皖南、赣北奥陶纪笔石立体标本形成环境的初步研究*

皖南、赣东北和赣西北地区奥陶纪笔石地层发育良好,笔石化石丰富。宁国组和胡乐组均为笔石相地层,但笔石的保存特点并不相同。立体保存的黄铁矿化笔石标本主要见于宁国组,而胡乐组的笔石几乎均为薄膜标本。在比较宁国组和胡乐组在岩性、颜色、化石、矿物和元素等方面的特点后发现,两者有较明显的差异。这表明宁国组和胡乐组形成时的环境是不同的,前者为弱还原环境,后者为较强的还原环境,而在研究区内影响笔石体立体保存的主要因素为还原环境和较高的铁含量。在还原环境下,铁可呈Fe~(2+)存在,笔石体内含有硫,死亡后经降解作用可生成H_2S;H_2S和Fe~(2+)结合可使笔石体黄铁矿化,从而使笔石体硬化而呈立体保存下来。宁国组的铁含量明显高于胡乐组,这似可以解释宁国组产有较多笔石立体标本的原因。     

Regeneration of fertile transgenic indica (group 1) rice plants following microprojectile transformation of embryogenic suspension culture cells

Regenerable embryogenic suspensions of elite Indica (group 1) rice varieties IR24, IR64, IR72 and an advanced Indica rice breeding line IR57311-95-2-3 were established within 6–8 weeks from 3–4 week old calli derived from mature seeds. Transgenic rice plants were obtained by introducing a plasmid carrying genes encoding hygromycin phosphotransferase (hph, conferring resistance to hygromycin B) and ß-glucuronidase (uidA), both driven by the CaMV 35S promoter, via particle bombardment of embryogenic suspensions. The effect of osmotic conditioning on transformation was evaluated. Regenerated plants were resistant to hygromycin B and expressed the uidA (GUS) gene. The growth of mother plants (R₀) was normal and seeds were produced. Southern blot analysis of R₀ and R₁ plants showed that hygromycin resistant plants contained intact hph genes that were inherited in a Mendelian fashion. A protocol for a simple, efficient, repeatable, genotype- and environment-independent Indica rice transformation system is described.Abbreviations 2,4-D 2,4-dichlorophenoxy acetic acid - NAA -naphthalene acetic acid - kb kilobase - GUS ß-glucuronidase - hph hygromycin B phosphotransferase     

硫酸盐对淡水养殖池塘表层底泥微生物的影响

硫酸盐引起的生态学效应已得到了越来越多的关注,但目前关于硫酸盐对养殖池塘底泥微生物的影响还知之甚少。【目的】探究不同浓度硫酸盐对养殖池塘底泥微生物的影响规律及可能的机制。【方法】本研究利用采集自养殖池塘的底泥和表层水构建了试验系统,研究了加入约0 mg/L （对照组）、30 mg/L （T1处理组）、150 mg/L （T2处理组）、500 mg/L （T3处理组） Na₂SO₄后表层底泥微生物的丰度、多样性、组成和共生网络的变化规律,并分析了环境影响因素。【结果】孵育第30天前,各实验组底泥微生物变化不大;但到第50天时,T2和T3处理组微生物丰度和多样性相比对照组均明显下降。相比其他实验组,T1处理组酸杆菌门（Acidobacteriota）、拟杆菌门（Bacteroidota）相对丰度出现显著升高（P<0.05）,T3处理组变形菌门（Proteobacteria）和放线菌门（Actinobacteriota）相对丰度出现显著升高（P<0.05）。与对照组相比,T1处理组增加了较多差异类群（62种）,而T3处理组差异类群大量减少（45种）。共生网络图分析显示硫酸盐浓度的增加引起了底泥微生物网络复杂性的增加,说明微生物群落可能通过自身的调节来响应硫酸盐引起的环境改变。冗余分析（redundant analysis,RDA）和相关性分析揭示底泥总有机碳、总氮和氧化还原电位是影响底泥微生物的主要环境因素,提示底泥微生物可能受到硫酸盐和有机质作用的影响。【结论】较长时间的高浓度硫酸盐会对池塘底泥微生物群落造成重要影响,微生物群落自身的转变和硫酸盐引起的有机质分解改变可能是造成微生物群落变化的关键因素。     

一株C3形态多重耐药大肠杆菌噬菌体生物学特性和基因组分析

【目的】多重耐药菌的出现对公共卫生安全构成严重威胁,本研究分离多重耐药大肠杆菌噬菌体,研究其生物学特性和基因组特征,为耐药菌的噬菌体疗法提供理论依据。【方法】使用双层平板法从污水样本中分离纯化大肠杆菌噬菌体;磷钨酸染色后通过透射电镜观察形态;测定其宿主范围,测定温度和pH稳定性、一步生长曲线和体外抑菌效果等生物学特性;体内抑菌试验评估噬菌体对多重耐药大肠杆菌N1203-1Af感染的大蜡螟幼虫的保护作用;基于全基因组测序对其基因组特点进行分析。【结果】本研究分离共得到5株大肠杆菌噬菌体,分别命名为pEC-S163-2.1、pEC-S163-2.2、pEC-M1167-5Ar.1、pEC-m1291-2Dr.1和pEC-N1203-2Af.1;电镜结果显示噬菌体pEC-N1203-2Af.1属于短尾噬菌体中罕见的C3形态型,头部较长,长是宽的2–3倍;pEC-N1203-2Af.1可裂解受试15株大肠杆菌中的3株;感染10 min后进入指数增长期,–20-50℃、pH值为4.0–10.0的环境下均能够保持稳定活性;大蜡螟幼虫感染大肠杆菌N1203-2Af后噬菌体pEC-N1203-2Af....     

声学指数在城市森林鸟类多样性评估中的应用

鸣声是鸟类之间进行沟通和传递信息的重要方式,这为通过声学监测评估鸟类多样性提供了独特的机会。利用声学指数快速评估生物多样性是一种新兴的调查方法,但城市森林中的复杂声环境可能会导致声学指数的指示结果出现偏差。为了解声学指数在城市森林中应用的可行性,本研究在北京市东郊森林公园设置了50个矩阵式调查样点,于2021年4–6月每月进行1次鸟类传统观测和同步鸣声采集,通过比较两种方法的结果来探究声学监测的有效性。采用Spearman相关分析和广义线性混合模型评估6个常用声学指数与鸟类丰富度和多度的关系,并衡量了每个指数的性能。结果表明:(1)本研究共记录到鸟类10目23科35种,通过声学监听识别的总物种数与传统鸟类观测相等,但具体鸟种存在差异;(2)不同月份间声学指数与鸟类丰富度和多度的相关性有明显差别,声学复杂度指数(ACI)和标准化声景差异指数(NDSI)优于其他指数,是评估鸟类多样性的关键变量;(3)声学指数对鸟类多度的预测能力(R²m=0.32,R2c=0.80)要高于丰富度(R²m=0.12,R2c=0.18)。声学指数为快速评估生物多样性提...