TUNEL法检测Cu~(2+)胁迫诱导的中国树花共生藻细胞的死亡

为了探讨铜离子胁迫对中国树花共生藻细胞毒害作用的机制及细胞死亡的原因,通过徒手切片,采用两种TUNEL检测法(Promega和Roche试剂盒)对2mmol/L和4mmol/L Cu~(2+)胁迫24h的中国树花地衣体共生藻细胞凋亡情况进行观察。结果表明:(1)伊文思蓝染色法检测结果显示,中国树花共生藻细胞活力在2和4mmol/L Cu~(2+)胁迫下显著降低,其细胞的死亡率随着Cu~(2+)浓度的提高和处理时间的延长而明显增加;(2)在2和4mmol/L Cu~(2+)胁迫条件下,中国树花共生藻细胞的TUNEL阳性细胞率在Promega试剂盒中检测结果分别为50.30%和31.21%,而在Roche试剂盒中共生藻细胞TUNEL阳性标记核分别为53.17%和36.88%,两种TUNEL检测法结果类似。(3)与伊文思蓝染色法检测的Cu~(2+)胁迫中国树花共生藻细胞活力相比,发现较低浓度的Cu~(2+)(2mmol/L)胁迫对地衣共生藻细胞的毒害作用可诱导启动细胞凋亡程序,而较高浓度的Cu~(2+)(4mmol/L)胁迫对地衣共生藻产生较严重的毒害则导致大部分细胞的坏死,只有极少数细胞出现细胞凋亡。(4)两种试剂盒均可用于较低浓度Cu~(2+)胁迫引起的地衣体共生藻细胞凋亡的检测;直接将徒手切片材料用于TUNEL细胞凋亡原位检测中也得到了较理想的结果,避免了制备石蜡切片的繁琐步骤,缩短实验时间,简化了实验流程。     

NaCl胁迫对宁夏枸杞叶和幼根显微及超微结构的影响

以宁夏枸杞为材料,采用超薄切片技术制备样品,应用光学显微镜和透射电镜分析了不同浓度NaCl胁迫条件下宁夏枸杞叶和幼根显微及超微结构的变化。结果表明：随着NaCl胁迫的加重,(1)叶片上表皮细胞增厚,栅栏组织细胞出现缩短现象,排列疏松且紊乱;幼根的初生结构无明显变化。(2)叶片栅栏组织中叶绿体不再紧靠在细胞膜上,叶绿体双层膜破坏,基粒片层松散排列,杂乱无章,出现膨胀和空泡现象,淀粉粒和嗜锇颗粒增多,叶肉细胞中线粒体发生轻微变化;幼根中皮层薄壁细胞线粒体形状发生改变,结构破坏,内膜和外膜模糊甚至破裂,大多数嵴模糊,出现空泡现象;细胞核解体,基质外溢。研究表明, 不同浓度的NaCl胁迫对宁夏枸杞叶片和幼根细胞的显微及超微结构影响不同,NaCl浓度大于200 mmol/L时,宁夏枸杞叶片和幼根细胞的显微及超微结构发生了明显变化,且叶肉细胞中线粒体的变化没有叶绿体的变化显著,推测叶肉细胞中线粒体的耐盐性比叶绿体强。     

Hg2+对海马齿叶肉细胞超微结构的影响

以红树林植物海马齿为材料,将生长一致的海马齿水培苗放到含有不同浓度Hg2+的营养液中进行Hg2+胁迫,用透射电镜观察海马齿叶肉细胞超微结构对不同浓度Hg2+胁迫的响应,以明确重金属汞对海马齿叶肉细胞超微结构的影响,探讨海马齿耐汞机制。结果表明:重金属汞能造成海马齿叶肉细胞不同程度的伤害,主要表现为对叶肉细胞中的叶绿体、线粒体、细胞核以及膜系统的伤害。随着Hg2+浓度不断升高,其叶绿体数目不断减少,形状由船型变成长形以及出现一些巨型叶绿体,类囊体系统受到伤害、基粒片层变得模糊不清。线粒体数目由于Hg2+浓度的不同而不同,形状由棒状变成圆形及椭圆形,线粒体双层膜结构与嵴变得模糊不清。细胞核也受到不同程度的伤害,核仁由一个变成多个,最后消失;同时细胞膜也受到伤害,主要表现为,不断的向胞内形成膜突起再形成空泡。最后在高浓度Hg2+胁迫下,随着叶肉细胞内细胞器的不断减少,最终造成细胞解体死亡。     

盐胁迫对玉米叶片叶肉细胞生物膜超微结构的影响

研究了NaCl胁迫对玉米叶肉细胞生物膜超微结构的影响. 结果表明：NaCl胁迫破坏了玉米叶片叶肉细胞生物膜的正常结构,50 mmol·L^-1 NaCl处理胁迫下,玉米叶肉细胞核膜,线粒体膜,细胞膜,叶绿体膜,液泡膜都受到不同程度的破坏,叶绿体基粒类囊体膨胀,间质片层空间增大,片层紊乱。100 mmol·L^-1 NaCl处理胁迫下,质膜,液泡膜,线粒体,叶绿体都受到严重的破坏。细胞质膜破坏,破损的叶绿体充斥在细胞间隙中;叶绿体外膜破坏,甚至解体消失,叶肉细胞中充满膜结构,基粒排列方向改变,垛叠层数减少,基粒和基质片层界限模糊不清,有的基粒解体消失,甚至叶绿体完全解体;核膜破坏、解体,核中的染色质高度凝缩;线粒体的数量增多,线粒体膜破坏,脊的数量减少,甚至整个线粒体破损解体;液泡膜破坏;由于各种生物膜的破坏,使细胞内充满许多囊状小泡、多泡体或斑层小体;叶肉细胞发生严重的质壁分离,严重时发生细胞壁断裂;甚至整个细胞溶解。     

地卷属5株共生藻的分离鉴定及抗逆性分析

[目的]了解地卷属的5种地衣共生藻分离、鉴定,并对其响应干旱、重金属、盐和温度等非生物胁迫因子的抗逆特性进行研究。[方法]采用涂布法进行分离培养及其结合形态与分子学方法初步鉴定分类地位;并采用PEG模拟法和重金属检测法研究对共生藻耐受性。[结果](1)在绿皮地卷(Peltigera apthosa)、犬地卷(Peltigera canina)、平盘软地卷(Peltigera elisabethae)、地卷(Peltigera rufescens)和膜地卷(Peltigera membranacea)等5种地卷中分离培养了5株藻(编号为1、2-1、4-2、6和7号),均属于杆裂丝藻属(Stichococcus)。(2)PEG模拟法对共生藻耐干旱特性的研究结果表明,1号、2-1号、6号和7号共生藻的干旱耐受性可达到30%,其中1号共生藻、2-1号和6号共生藻的PEG耐受性达40%。共生藻对不同重金属离子的耐受性存在显著差异:对1.0 mmol/L浓度Cu~(2+)、Cd~(2+)和Fe~(2+)均有一定的耐受性藻株为1号、2-1号、6号和4-2号共生藻;对1.0 mmol/L Zn~(2+)具有耐受性的藻株为6号、7号和4-2号共生藻。其中6号藻株对Cu~(2+)和Fe~(2+)的耐受性可高达1.5 mmol/L,7号藻株也对Cu~(2+)耐受性达到1.5 mmol/L',6号藻株对不同重金属的耐受性显著高于其它藻株。5株共生藻中,4-2号和7号藻对0.3 mol/L氯化钠具有一定的耐受性,1号和6号共生藻对Na Cl的耐受性最为强,可达到0.4 mol/L。其中(6号、7号、2-1号)在35℃条件下也能生长,所有藻株均显示敏感性。[结论]对干旱、重金属、盐和温度等非生物胁迫抗逆特性最高的藻株为地卷中分离的6号藻株。研究结果证实了地卷属地衣中包含了具有较强的生存力和耐干旱、重金属和盐胁迫适应能力的藻类品种。     

铜胁迫对穿心莲幼苗生长及生理特性的影响

通过对盆栽穿心莲(Andrographis paniculata)幼苗浇灌Cu SO4溶液实验,研究外施Cu2+对穿心莲幼苗的生理特性和药效成分含量的影响。结果显示,外施Cu2+对穿心莲幼苗的生长、生理生化指标和穿心莲内酯、脱水穿心莲内酯的含量均有显著影响。当Cu SO4溶液浓度超过6.25 mmol/L时,Cu2+能显著抑制穿心莲幼苗株高、叶长、叶宽的增长,且随胁迫时间的延长和Cu2+浓度的增大抑制作用增强;穿心莲叶片中超氧化物歧化酶(SOD)活性和丙二醛(MDA)含量均随Cu2+浓度增大和胁迫时间的延长而升高,当Cu SO4溶液浓度达到12.5 mmol/L且胁迫20 d和30 d时,叶片中SOD活性达到对照组的168.3%和171.18%;过氧化物酶(POD)、过氧化氢酶(CAT)活性则随Cu2+浓度的增大呈先升高后下降的趋势;当外施Cu SO4溶液浓度大于1.25 mmol/L时,与对照相比,穿心莲药效成分穿心莲内酯和脱水穿心莲内酯的含量均显著降低(P0.05)。研究结果表明,外施Cu SO4溶液浓度高于6.25 mmol/L时,能显著影响穿心莲幼苗的生理特性和有效成分含量,从而降低穿心莲药材的产量和质量。     

外源Ca2+和IBA对NaCl胁迫下能源植物杂交狼尾草幼苗生长的影响

以能源植物杂交狼尾草(Pennisetum americanum×P.purpureum)为实验材料,在NaCl胁迫条件下用外源IBA(100 mg/L),CaCl_2(浓度分别为0、1、2、5 mmol/L)处理杂交狼尾草幼苗,处理3周后测定植物的存活率、鲜重、干重、株高、生根数和地上部分、地下部分的离子含量。结果表明,经过IBA溶液预处理的杂交狼尾草幼苗的存活率、鲜重、干重、株高、生根数明显高于未处理的幼苗;在NaCl胁迫下,随着外源Ca~(2+)浓度的升高,杂交狼尾草幼苗的存活率、鲜重、干重、株高、生根数以及Ca~(2+)含量都明显升高并在CaCl_2浓度为2 mmol/L时达到最大值;随着外源Ca~(2+)浓度的升高,Na~+含量、Na~+/K~+降低,当CaCl_2的浓度为2mmol/L时,Na~+含量、Na~+/K~+最低。以上结果表明外源Ca~(2+)和IBA对NaCl胁迫下杂交狼尾草幼苗生长有促进作用,可以缓解NaCl胁迫对杂交狼尾草幼苗生长的抑制作用,提高杂交狼尾草幼苗在NaCl胁迫下的成活率;缓解盐害的最适的Ca~(2+)浓度为2mmol/L。     

三种地卷响应Cu~(2+)胁迫的差异分析

基于谷胱甘肽(Glutathione,GSH)含量变化和铜吸附性分析地卷、平盘软地卷和犬地卷响应Cu~(2+)胁迫的差异,以了解谷胱甘肽在低等生物地衣抗重金属胁迫中的作用。分光光度法和火焰原子吸收方法分别测定地衣体的GSH与细胞内、外的铜含量。结果显示,低浓度Cu~(2+)胁迫下,3种地卷GSH均呈上升趋势,4 mmol/L时达最高;5-8 mmol/L时,地卷和犬地卷的GSH逐步下降较明显,但仍显著高于对照组,而平盘软地卷GSH在3-5 mmol/L Cu~(2+)范围差异不显著,Cu~(2+)5 mmol/L时才出现较明显的下降(P0.05)。4 mmol/L Cu~(2+)处理时间不同时,犬地卷的GSH变化与处理时间正相关,而地卷和平盘软地卷的GSH出现波动式变化(6 h增加,12 h下降,18-24 h上升)。3种地卷胞外铜与Cu~(2+)浓度和处理时间呈正相关并显著高于胞内铜(P0.01),而胞内富集的铜与地衣GSH变化相对应呈高-低-高的变化趋势。菌藻共生的特殊生物-地卷类似于高等植物可诱导合成GSH缓解胁迫产生的伤害,3种地卷的铜耐受性差异与其铜吸附性和GSH合成能力密切相关。     

两种地衣共生藻对铜和锌的耐受性及吸附特性研究

重金属污染生物修复中,藻类对重金属的吸附潜力引起诸多研究者的关注。为了探讨从地衣体分离培养的地衣共生藻对重金属Cu~(2+)、Zn~(2+)吸附特性及其耐受性的差异,以2种地衣共生藻为研究材料,采用Evan’s blue染色法、BCO和双硫腙分光光度法测定地衣共生藻细胞活率,培养液及藻体内的Cu~(2+)、Zn~(2+)含量。结果显示:不同浓度Cu~(2+)、Zn~(2+)胁迫下,2种地衣共生藻的细胞活力及重金属吸附特性有所差异,对Cu~(2+)胁迫的耐受性及吸附性为:P.EB;Zn~(2+)胁迫下,培养至9d时耐受为:P.E B,随着培养时间的延长P.E的细胞活力急剧下降并低于B,但吸附率还是处于P.E B;并且2种地衣共生藻对Zn~(2+)胁迫的耐性及吸附性明显高于Cu~(2+)。研究发现,来自菌藻共生的特殊生物-地卷属地衣的两种藻类比一些自由生长的藻类对铜和锌胁迫具有较高的耐受性及吸附性。     

Na2CO3胁迫对星星草叶肉细胞超微结构的影响

利用透射电镜技术对Na2CO3胁迫下星星草叶肉细胞超微结构进行了观察。结果表明：未胁迫的叶肉细胞排列疏松,各种细胞器结构完整,叶绿体含少量淀粉粒和脂质球。轻度盐胁迫（2g/L,4g／LNa2CO3）对叶肉细胞超微结构影响较小。中度盐胁迫（6g／L,8g／L Na2CO3）引起叶肉细胞超微结构的变化,叶绿体类囊体肿胀,基粒紊乱,不含淀粉粒,脂质球数量增加,叶绿体由原来的梭形或椭球形变成圆球状;部分线粒体嵴消失,出现晶体结构;中央大液泡破裂;核逐渐降解。高度盐胁迫（10g／L,12g／LNa2CO3）下,叶绿体片层结构消失,脂质球数量增加,体积变大,被大量的膜片层所包围,叶绿体内、外膜消失,叶肉细胞中看不到叶绿体的存在;膜片层包围线粒体;叶肉细胞中可见大量的泡状结构和膜片层,叶肉细胞死亡。上述结果表明,细胞器特别是叶绿体膜结构的破坏与盐胁迫叶肉细胞最终死亡密切相关。     

转录调节因子σ~(38)介导铜绿假单胞菌绿脓菌素合成代谢调控

【目的】为了进一步鉴定铜绿假单胞菌转录调控因子σ~(38)对2个拷贝吩嗪合成基因簇(phz A1-G1和phz A2-G2)的具体调控方式并推定介导绿脓菌素合成代谢的可能调控机制。【方法】根据铜绿假单胞菌基因组信息,利用同源重组原理构建rpo S基因缺失突变株Δrpo S以及克隆全长rpo S基因作互补分析;再以单一吩嗪基因簇缺失突变株Δphz1和Δphz2为出发菌株,分别构建rpo S缺失突变株Δrpo Sphz1和rpo S插入突变株Δrpo Sphz2,测定并比较野生株及相关突变株的绿脓菌素合成量,初步推定σ~(38)因子对2个不同吩嗪基因簇表达的调控方式。【结果】在GA培养基中,突变株Δrpo S的绿脓菌素合成量比野生株显著增加;互补分析证实,σ~(38)可使突变株Δrpo S的绿脓菌素降低并接近野生株PAO1水平;与对照株Δphz1相比,突变株Δrpo Sphz1的绿脓菌素合成量因σ~(38)因子缺失而显著减少;而与对照株Δphz2相比,突变株Δrpo Sphz2的绿脓菌素合成量因σ~(38)因子缺失显著增加。【结论】转录调控因子σ~(38)对铜绿假单胞菌绿脓菌素的合成代谢的确具一定的负调控作用;结合已报道的研究结果,初步推定:σ~(38)因子通过负调控吩嗪基因簇phz1,正调控吩嗪基因簇phz2的表达实现对绿脓菌素合成代谢的调控。     

Mn~(2+)对肠膜状明串珠菌产右旋糖酐的影响

肠膜状明串珠菌在其产生的右旋糖酐蔗糖酶的作用下,以蔗糖为原料转化合成右旋糖酐和产生果糖。着重进行了Mn~(2+)对肠膜状明串珠菌Lm-1226发酵产右旋糖酐影响的初步探索。对Mn~(2+)对肠膜状明串珠菌Lm-1226的生长,产果糖、右旋糖酐和右旋糖酐蔗糖酶,右旋糖酐蔗糖酶作用影响进行了研究。一定浓度的Mn~(2+)对肠膜状明串珠菌Lm-1226的生长具有促进作用; Mn~(2+)抑制肠膜状明串珠菌Lm-1226发酵产果糖和右旋糖酐,且Mn~(2+)浓度越高,抑制性越强; Mn~(2+)对肠膜状明串珠菌Lm-1226发酵产右旋糖酐蔗糖酶有抑制作用; Mn~(2+)对右旋糖酐蔗糖酶具有较强的激活作用,激活作用可达158%,最适Mn~(2+)浓度为5. 0 mmol/L。     

RETRACTED ARTICLE: Analysis of the physiological mechanism of salt-tolerant transgenic rice carrying a vacuolar Na+/H+ antiporter gene from Suaeda salsa

Salt stress is one of the most serious factors limiting the productivity of agricultural crops. Increasing evidence has demonstrated that vacuolar Na⁺/H⁺ antiporters play a crucial role in plant salt tolerance. In the present study, we expressed the Suaeda salsa vacuolar Na⁺/H⁺ antiporter SsNHX1 in transgenic rice to investigate whether this can increase the salt tolerance of rice, and to study how overexpression of this gene affected other salt-tolerant mechanisms. It was found that transgenic rice plants showed markedly enhanced tolerance to salt stress and to water deprivation compared with non-transgenic controls upon salt stress imposition under outdoor conditions. Measurements of ion levels indicated that K⁺, Ca²⁺ and Mg²⁺ contents were all higher in transgenic plants than in non-transformed controls. Furthermore, shoot V-ATPase hydrolytic activity was dramatically increased in transgenics compared to that of non-transformed controls under salt stress conditions. Physiological analysis also showed that the photosynthetic activity of the transformed plants was higher whereas the same plants had reduced reactive oxygen species generation. In addition, the soluble sugar content increased in the transgenics compared with that in non-transgenics. These results imply that up-regulation of a vacuolar Na⁺/H⁺ antiporter gene in transgenic rice might cause pleiotropic up-regulation of other salt-resistance-related mechanisms to improve salt tolerance.Fengyun Zhao and Zenglan Wang contributed equally to this work.     

大肠杆菌NAD+合成关键酶的克隆表达及发酵优化

【目的】烟酰胺腺嘌呤二核苷酸(NAD~+)在细胞基因表达、氧化还原反应、能量代谢以及调控细胞生命周期中具有重要的作用,其细胞内含量是能量效率的关键因素。强化辅因子合成策略,获得高产NAD~+菌株,对于NAD~+依赖型氧化还原反应的速率和调节相关生化合成途径的代谢流具有重要意义。【方法】首先通过内源性调节,对代谢途径中的关键酶基因进行强化,过量表达和共表达NAD~+合成途径中的关键酶基因pncB、nadD和nadE;其次,通过外源调节增加NAD~+前体物,优化诱导条件提高发酵过程中关键酶的表达量,增加NAD~+的合成量;最后在单因素优化试验的基础上,以NAD~+含量为响应值,采用Box-Bohnken试验设计方法,研究3个显著性影响因素相互作用对NAD~+积累量的影响,确定最佳的优化条件。【结果】根据关键酶基因强化策略,构建了7株重组菌,其中重组菌E.coli BL21/p ET-21a-nad E-pncB胞内NAD~+含量相比初始菌株E.coli BL21/pET-21a提高了405.2%。通过对该菌株诱导条件和NAD~+合成前体的优化,使用Design Expert 8.0分析实验数据,得出该重组菌株的最佳发酵条件为:诱导温度控制在15–20 oC,OD_(600)为0.6–0.8时添加IPTG 0.63 mmol/L、烟酸15.8 mg/L、诱导时长控制在24 h。NAD~+含量在最优条件下实验验证值可达43.16μmol/g DCW,与优化前相比提高了123.6%,与初始菌株相比提高了1029.8%。【结论】在大肠杆菌中共表达关键酶基因pncB和nadE,胞内NAD~+合成量明显增加,前体物以及诱导条件的外源调节使NAD~+积累量达到最佳优化值。实现了提高NAD~+含量的目标,胞内辅因子浓度的增加为提高生物催化效率奠定了可行性基础。     

Isolation, cloning and expression analysis of EcPMA1, a putative plasma membrane H-ATPase transporter gene from the biotrophic pathogenic fungus Erysiphe cichoracearum

Little is known at the molecular level about the transporters involved in nutrient transfer in the plant/powdery mildew interaction. A PCR-based approach was used to identify and isolate a partial-length cDNA coding for an isoform of the plasma membrane H⁺-ATPase (EcPMA1) in the biotrophic pathogenic fungus Erysiphe cichoracearum. Southern analysis suggests that EcPMA1 exists as a single-copy gene. Sequence analysis indicated a high similarity of EcPMA1 to other fungal H⁺-ATPases. Expression of EcPMA1 increases in infected Arabidopsis leaves as the disease progresses, correlating with the growth of the pathogen.     

Mitochondrial function in Parkinson's disease cybrids containing an nt2 neuron-like nuclear background

Mitochondria likely play a role in Parkinson's disease (PD) neurodegeneration. We modelled PD by creating cytoplasmic hybrid (cybrid) cell lines in which endogenous mitochondrial DNA (mtDNA) from PD or control subject platelets was expressed within human teratocarcinoma (NT2) cells previously depleted of endogenous mtDNA. Complex I activity was reduced in both PD cybrid lines and in the platelet mitochondria used to generate them. Under basal conditions PD cybrids had less ATP, more LDH release, depolarized mitochondria, less mitochondrial cytochrome c, and higher caspase 3 activity. Equivalent MPP+ exposures are more likely to trigger programmed cell death in PD cybrid cells than in control cybrid cells. Our data support a relatively upstream role for mitochondrial dysfunction in idiopathic PD.     

镉胁迫下硒对罗汉果组培苗光合特性的影响

实验以罗汉果组培苗为材料,室内栽培在内装市售营养土的塑料盆中,以0、10、50、100、200mg·kg-1浓度镉离子和1mg·kg-1浓度硒处理,培养20d后分析罗汉果幼苗的相关光合生理指标。结果表明:低浓度Cd2+对叶片叶绿素含量、光合速率(Pn)、蒸腾速率(Tr)、气孔导度(Gs)影响不大或稍有上升,但高浓度镉离子处理植株叶片的叶绿素含量、光合速率(Pn)、蒸腾速率(Tr)、气孔导度(Gs)明显下降;随Cd2+处理浓度的增加,叶片胞间CO2浓度(Ci)呈现上升趋势;加硒则延缓叶绿素下降,促进光合速率(Pn)、蒸腾速率(Tr)、气孔导度(Gs)上升,降低叶片胞间CO2浓度(Ci)。表明高浓度镉离子的毒害导致罗汉果组培苗叶片光合性能受到伤害,从而影响罗汉果幼苗生长。镉硒混合处理反映出硒对镉的毒害有缓解作用。     

Natural Selection During Functional Divergence to LMP7 and Proteasome Subunit X (PSMB5) Following Gene Duplication

The LMP7 and PSMB5 genes were created through an ancient gene duplication event of their ancestral locus. These proteins contain an active site of proteolysis, and LMP7 replaces PSMB5 as a component of the 20S proteasome after stimulation of cells by interferon-. Replacement of PSMB5 by LMP7 changes the profile of the products of 20S proteasome processing, predisposing digested peptides for transport to and display by the immune system. The purpose of this study is to investigate evolutionary forces influencing functional divergence between LMP7 and PSMB5 following duplication. Levels of synonymous and nonsynonymous substitution rates are estimated to infer differences in levels of natural selection. Estimates of substitution rates indicate that natural selection elevated rates of nonsynonymous substitution in LMP7 following gene duplication, whereas PSMB5 experienced an increase in substitution rate that was not likely due to diversifying natural selection following duplication. Following initial divergence, nearly neutral mutations have dominated gene evolution in both lineages. The LMP7 gene locus provides a rare example of a protein with specialized function arising from duplication and divergence of a housekeeping protein by way of natural selection.Reviewing Editor: Dr. Rasmus Nielsen     

p33 Enhances UVB-Induced Apoptosis in Melanoma Cells

The biological functions of the tumor suppressor ING1 have been studied extensively in the past few years since it was cloned. It shares many biological functions with p53 and has been reported to mediate growth arrest, senescence, apoptosis, anchorage-dependent growth, chemosensitivity, and DNA repair. Some of these functions, such as cell cycle arrest and apoptosis, have been shown to be dependent on the activity of both ING1 and p53 proteins. Two recent reports by Scott and colleagues demonstrate that p33^ING1 (one of the ING1 isoforms) translocates to the nucleus and binds to PCNA upon UV irradiation. Here we report that p33^ING1 mediates UV-induced cell death in melanoma cells. We found that overexpression of p33^ING1 increased while the introduction of an antisense p33^ING1 plasmid reduced the apoptosis rate in melanoma cells after UVB irradiation. We also demonstrated that enhancement of UV-induced apoptosis by p33^ING1 required the presence of p53. Moreover, we found that p33^ING1 enhanced the expression of endogenous Bax and altered the mitochondrial membrane potential. Taken together, these observations strongly suggest that p33^ING1 cooperates with p53 in UVB-induced apoptosis via the mitochondrial cell death pathway in melanoma cells.     

梅毒螺旋体的营养物质转运及能量合成相关代谢机制研究

梅毒螺旋体(Treponemapallidum,Tp)是严重危害人类健康的性传播疾病梅毒的病原体,目前仍难以实现体外人工培养.Tp在感染期间是如何获得足够的能量来完成其复杂的致病过程迄今不明.本文就Tp的葡萄糖转运、糖酵解途径、丙酮酸去路以及NAD+再生的研究进展做一综述,旨在为探索Tp尚未明了的生理代谢机能、突破Tp...