Does cypermethrin affect enzyme activity,respiration rate and walking behavior of the maize weevil (Sitophilus zeamais)?

Insecticides cause a range of sub‐lethal effects on targeted insects, which are frequently detrimental to them. However, targeted insects are able to cope with insecticides within sub‐lethal ranges, which vary with their susceptibility. Here we assessed the response of three strains of the maize weevil Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae) to sub‐lethal exposure to the pyrethoid insecticide cypermethrin. We expected enzyme induction associated with cypermethrin resistance since it would aid the resistant insects in surviving such exposure. Lower respiration rate and lower activity were also expected in insecticide‐resistant insects since these traits are also likely to favor survivorship under insecticide exposure. Curiously though, cypermethrin did not affect activity of digestive and energy metabolism enzymes, and even reduced the activity of some enzymes (particularly for cellulase and cysteine‐proteinase activity in this case). There was strain variation in response, which may be (partially) related to insecticide resistance in some strains. Sub‐lethal exposure to cypermethrin depressed proteolytic and mainly cellulolytic activity in the exposed insects, which is likely to impair their fitness. However, such exposure did not affect respiration rate and walking behavior of the insects (except for the susceptible strain where walking activity was reduced). Walking activity varies with strain and may minimize insecticide exposure, which should be a concern, particularly if associated with (physiological) insecticide resistance.     

Lethal and sub‐lethal impacts of pulsed laser irradiations on the larvae of the fouling barnacle Balanus amphitrite

Laboratory experiments were conducted to study the impact of laser irradiation on the larvae of the fouling barnacle Balanus amphitrite. Research pertaining to fouling invertebrate larvae‐laser interaction is sparse and, hence, data on this aspect were thought significant in order to consider pulsed low power laser irradiations as a possible future antifouling tool. Lethal and sub‐lethal impacts of four very low laser fluences, viz. 0.013, 0.025, 0.05 and 0.1 J cm^‐2 for three different durations, viz. 2, 10 and 30 s were investigated. Three growth stages of barnacle larvae, viz. nauplii stage II, nauplii stage IV and cyprids were exposed to the mentioned laser fluences for different durations. While lethal impact was assessed immediately after and 1 d after irradiation, sub‐lethal impacts were studied by monitoring the success rate of the irradiated nauplii in reaching the cyprid stage. In addition, the swimming speed of VI^th stage nauplii after irradiation was studied. In the case of cyprids, in addition to the mortality measurement immediately after and 1 d after irradiation, the settlement rate was investigated. In all the above experiments, non‐irradiated larvae served as controls. The results showed an increase in mortality with increasing laser fluence and duration of irradiation. Irradiation for 2 s resulted in significant mortality in nauplii, while it was less in the case of cyprids. In II^nd stage nauplii, the mortality immediately after irradiation for 2 s varied from 14.8±2.12 to 97.1±4.1% for laser fluences of 0.013 and 0.1 J cm^‐2, respectively. However, in cyprids, the mortality immediately after irradiation for 2 s varied from 12.2±3 to 13.4±1.2% for fluences of 0.013 and 0.1 J cm^‐2, respectively. The mortality in IV^th stage nauplii was less than that for II^nd stage nauplii but more than that for cyprids. There was a significant increase in mortality with time after irradiation. The formation of cyprids from the irradiated larvae was significantly less than that observed for non‐irradiated larvae. Also, the irradiated larvae showed a significantly slower swimming speed compared to the control samples. The settlement rate in cyprids was reduced significantly by the laser irradiation. This was true even for the lowest fluence and shortest period of irradiation tested. Thus, the results of the experiment showed that even a low power pulsed laser irradiation of 0.013 J cm^‐2 for 2 s can cause significant damage to fouling barnacle larvae.     

藻蓝蛋白抑制人结肠癌SW480细胞增殖的初步研究

目的 研究藻蓝蛋白对人结肠癌SW480细胞的体外抑瘤作用,为进一步探讨藻蓝蛋白抑制肿瘤的机制提供依据。方法 用不同浓度的藻蓝蛋白处理结肠癌SW480细胞后,应用MTT实验来检测藻蓝蛋白对细胞增殖的抑制作用并计算出半数抑制率,利用HE染色法和电镜技术观察凋亡细胞形态结构,采用流式细胞术分析其对SW480细胞周期的影响。结果 MTT试验证明藻蓝蛋白能够抑制SW480细胞的增殖,且呈时间和剂量依赖性;HE染色以及电镜的观察结果显示藻蓝蛋白能够诱导SW480细胞的凋亡,流式细胞术显示SW480细胞被阻滞在G2/M期,G0/G1期细胞比例降低。结论 藻蓝蛋白在体外能够抑制结肠癌SW480细胞的增殖,具有可开发人结肠癌治疗光敏剂应用前景。     

Salidroside induces cell-cycle arrest and apoptosis in human breast cancer cells

Recently, salidroside (p-hydroxyphenethyl-β-d-glucoside) has been identified as one of the most potent compounds isolated from plants of the Rhodiola genus used widely in traditional Chinese medicine, but pharmacokinetic data on the compound are unavailable. We were the first to report the cytotoxic effects of salidroside on cancer cell lines derived from different tissues, and we found that human breast cancer MDA-MB-231 cells (estrogen receptor negative) were sensitive to the inhibitory action of low-concentration salidroside. To further investigate the cytotoxic effects of salidroside on breast cancer cells and reveal possible ER-related differences in response to salidroside, we used MDA-MB-231 cells and MCF-7 cells (estrogen receptor-positive) as models to study possible molecular mechanisms; we evaluated the effects of salidroside on cell growth characteristics, such as proliferation, cell cycle duration, and apoptosis, and on the expression of apoptosis-related molecules. Our results demonstrated for the first time that salidroside induces cell-cycle arrest and apoptosis in human breast cancer cells and may be a promising candidate for breast cancer treatment.     

根皮素对HepG2肝癌细胞增殖和凋亡影响的实验研究

目的：探讨根皮素对人肝癌HepG2细胞增殖和凋亡的影响。方法：MTT法检测不同浓度（30、40、50 ug/mL）根皮素对肝癌HepG2 细胞增殖的抑制作用,流式细胞技术检测根皮素对HepG2细胞凋亡的影响,ELISA 法检测不同浓度根皮素干预后细胞中Bcl-2 和Bax表达的变化,Western blot法检测30 ug/mL根皮素在8,16,24 小时后检测p-AKT 蛋白表达情况。结果：30、40 和50ug/mL 的根皮素对肝癌HepG2 细胞的增殖均有抑制作用（P＜0.01）,同时,30、40 和50 ug/mL 的根皮素在24 小时后可诱导HepG2 细胞发生早期凋亡,凋亡率分别为0.1321± 0.0224, 0.2607± 0.0457, 0.3712± 0.0884（P＜0.01）;另外,30、40 和50 ug/mL的根皮素作用24 小时后细胞内Bcl-2 表达降低,Bax 表达增高（P＜0.01）;最后,30 ug/mL根皮素可以明显减少p-AKT 表达量,这种作用呈现时间依赖性。结论：根皮素能够抑制肝癌HepG2 细胞的增殖和促进细胞凋亡。     

吡虫啉对意大利蜜蜂乙酰胆碱酯酶的亚致死效应

【目的】确定吡虫啉对意大利蜜蜂Apis mellifera的致死中浓度,探究吡虫啉对意大利蜜蜂乙酰胆碱酯酶的亚致死效应。【方法】本文采用药膜法、点滴法和饲喂法测定吡虫啉对意大利蜜蜂的毒力曲线,及蜜蜂接触吡虫啉后头部乙酰胆碱酯酶活性的变化。应用RT-q PCR技术研究饲喂LC5浓度吡虫啉后,蜜蜂乙酰胆碱酯酶基因Ace1和Ace2的m RNA相对表达量。【结果】饲喂法、点滴法和药膜法3种方法测定的吡虫啉对意大利蜜蜂的致死中浓度分别是7.15 mg/L、0.078 ng/蜂和51 ng/cm2。3种作用方式下,吡虫啉均抑制了乙酰胆碱酯酶活性;随着浓度增加,ACh E酶活性处于下降状态,但降低较少。LC5浓度的吡虫啉对蜜蜂ACh E活性具有明显影响,24 h内ACh E活性呈现增强-抑制-增强的趋势。饲喂蜜蜂LC5亚致死浓度的吡虫啉后,Ace1和Ace2被诱导表达,但在1、2和16 h与对照无明显差异。【结论】亚致死浓度的吡虫啉对蜜蜂乙酰胆碱酯活性具有抑制作用,并且存在明显的剂量效应和时间效应,对Ace1和Ace2具有诱导效应,酶活性水平和m RNA相对表达水平不一致。     

Caution regarding the combined effects of extracellular matrices and nutrient media on cultured endothelial cells

To study the influence of smooth muscle cells (SMC) on endothelial cells (EC), different co-culture designs are available, including EC seeding on SMC extracellular matrix (ECM). We explored human umbilical vein endothelial cell (HUVEC) adhesion and proliferation on either in situ or coated ECM, elaborated by HUVECs or human arterial smooth muscle cells (HUASMCs), in the presence of different nutrient media containing varying amounts of fetal calf serum. Coating wells with HUVEC or HUASMC ECMs did not improve HUVEC adhesion 1 h after cell seeding, compared with uncoated wells. HUVEC adhesion on in situ HUVEC-ECM and HUASMC-ECM was significantly increased compared with uncoated wells. The substratum upon which cells are maintained was found to play a crucial role, in conjunction with the medium to which HUVECs are exposed for their proliferative response. These results stress the importance of selecting media in relation to the particular substratum, in order to avoid misinterpretation of data.