稻褐飞虱致害性遗传与性别的关联性研究

以单雌蜜露排泄量和体重增量作为致害性指标,研究了稻褐飞虱Nilaparvata lugens (Stål)的致害性遗传与性别的关联性。褐飞虱弱致害种群（TN1种群）与强致害种群（Mudgo种群或ASD7种群）（已分别用水稻品种TN1、Mudgo和ASD7强迫饲养82代）在抗虫品种水稻上的致害力差异明显,适宜作为遗传分析的亲本材料。当用蜜露排泄量作为致害性指标时,两种处理（TN1种群与Mudgo种群,TN1种群与ASD7种群）正、反杂交的F₁代雌成虫平均蜜露排泄量存在极显著差异,由此可以推断正交F₁代群体与反交F₁代群体致害性存在明显差别。用体重增量作为致害性指标进行实验,得到的结论与上述研究完全一致。以上的结果可推测稻褐飞虱致害性可能属于伴性遗传。     

药用野生稻对褐飞虱抗性基因的遗传分析及利用研究

从198份广西药用野生稻中筛选出3份对褐飞虱高抗（0级）的材料,用高抗材料与感虫材料杂交,结果表明其抗性是受一对显性基因控制;与14个已知抗褐飞虱基因品种杂交、回交和自交,对BC2F2后代材料进行了抗性遗传分析,等位性测定结果表明,抗源材料与已知的14个抗性基因不等位,结果发现广西药用野生稻与国外药用野生稻的抗性基因（隐性基因）不同。初步认为它是一个新的抗性基因。在利用方面,通过幼胚离体培养获得绿苗,经多代回交和自交,成功地将CC染色体组中的抗性基因转育到栽培稻中,获得了BC4F5高世代、异源附加系。     

利用回交重组自交群体检测水稻抗褐飞虱数量性状基因座

利用由98个系组成的Nipponbare/Kasalath//Nipponbare回交重组自交系（Backcross Inbred lines,BILs）作图群体（BC1F9）,进行水稻抗褐飞虱数量性状基因座（Quantative Trait Locus,QTL）的检测和遗传效应分析。采用苗期集团鉴定方法,并以死苗率作为抗褐飞虱表型值,分析亲本和98个BILs抗褐飞虱表现。共检测到3个苗期抗褐飞虱QTL,分别位于2、10和12染色体上,各QTL的LOD值为2.01～2.33,贡献率为10.4%～16.6%,可解释群体总表型变异的39.0%。这3个数量性状基因座对褐飞虱的抗性均来自抗虫亲本Kasalath。与这些数量性状基因座连锁的分子标记可望应用于聚合多个抗性基因,培育对褐飞虱具有水平抗性水稻新品种的育种实践中。     

小菜蛾对阿维菌素的抗性遗传方式 和相对适合度研究

就小菜蛾Plutella xylostella对阿维菌素的抗性遗传方式和抗性品系的相对适合度进行了研究。室内选育的阿维菌素抗性品系与同源的敏感品系杂交、F₁代自交、F₁代与亲本回交,结果表明：杂交后的显性度（D）分别为-0.64和-0.52,说明小菜蛾对阿维菌素的抗性是常染色体、不完全隐性遗传;χ²检验证实,可能是多基因控制的抗性遗传。杂交F₁代乙酰胆碱酯酶（AChE）、羧酸酯酶（CarE）和谷胱甘肽转移酶（GST）活性比抗性亲本有所降低,F2代及回交后代三种酶的活性继续降低。种群适合度研究表明,抗性品系相对于敏感品系有0.84的适合度。     

湖北省褐飞虱对吡虫啉、噻嗪酮及氟虫腈的抗药性监测

采用稻茎浸渍法监测湖北省武穴、天门、监利、通城、孝感、公安及枣阳七地褐飞虱Nilaparvata lugens(Sta1)田间种群对吡虫啉、噻嗪酮、氟虫腈的抗药性。结果表明:2006、2007和2008年3年7地褐飞虱种群对吡虫啉的抗性分别为98.89～389.19倍、69.00～153.33倍和56.32～116.89倍,达高水平至极高水平抗性,但3年期间总体抗性水平呈现一定程度的下降趋势;2007和2008年2年7地褐飞虱对噻嗪酮的抗性分别为13.39～41.06倍和6.94～20.44倍,达低水平至高水平抗性;2007和2008年2年7地褐飞虱对氟虫腈抗性分别为0.97～2.64倍和0.63～1.42倍,为敏感阶段。此外,还对褐飞虱的治理进行讨论。     

褐飞虱抗药性研究现状

褐飞虱Nilaparvata lugens(Stal)对杀虫剂产生抗药性是其近年来暴发频繁的重要原因。文章综述国内外关于褐飞虱抗药性的研究成果,包括褐飞虱抗性测定方法、抗药性的发展、交互抗性、抗性遗传、抗性机理及抗性治理等。田间褐飞虱种群对新烟碱类药剂产生不同程度的抗药性,其中对吡虫啉产生高水平到极高水平抗性,对氯噻啉和噻虫嗪分别产生中等水平和低水平的抗药性,对呋虫胺和烯啶虫胺仍然处于敏感性阶段。此外,褐飞虱种群对噻嗪酮(昆虫生长调节剂)产生低水平到中等水平抗性。长期大面积使用化学药剂是褐飞虱产生抗药性的重要原因。因此,必须加强褐飞虱的抗性治理,以延缓其抗药性进一步发展。     

我国北方玉米品种个体产量潜力与氮利用效率研究

采用大田试验,在低密度条件下, 研究了我国北方1990年以来大面积种植的50个玉米主栽品种个体产量潜力和N利用效率.探测分析和正态分布检测结果表明,单株籽粒产量（GY）、千粒重（KW）、单株生物产量（AB）、籽粒收获指数（HI_G）、N利用效率（NUE）和N收获指数（HI_N）6个指标分别符合正态分布N（265.1,44.50²）、N（322.3,36.91²）、N（515.8,64.73²）、N（0.514,0.06²）、N（43.0,5.37²）和N（0.643,0.06²）,其变化范围为GY 198.35～345.22 g/株、KW 241.50～391.82 g/1 000粒、AB 402.34～712.84 g/株、HI_G 0.39～0.63、NUE 31.18～57.35 kg grain·kg^-1N和HI_N0.47～0.74.相关分析表明,产量与NUE高度正相关（偏相关系数0.471**,P=0.01）,而籽粒千粒重与NUE呈显著性负相关（Pearson相关系数-0.427**,P=0.02）.对GY和NUE进行分层聚类,将北方玉米品种划分为高产高NUE型、低产低NUE型和中间型,目前高产高NUE型玉米品种相对较少,仅占24%.     

湖北稻区褐飞虱田间种群对常用杀虫剂抗药性监测

【目的】明确目前褐飞虱Nilaparvata lugens田间种群对常用防治药剂的抗性现状,为制定褐飞虱的科学用药策略提供科学依据。【方法】于2009-2014年采用稻茎浸渍法监测了湖北褐飞虱武穴梅川、枣阳十里铺、孝感陈店、鄂州长港和武汉江夏稻田的褐飞虱田间种群对11种杀虫剂的敏感性。【结果】湖北稻区褐飞虱田间种群已对吡虫啉(抗性倍数RR=101.8~1 239.4)、噻嗪酮(RR=15.9~1 326.3)产生高水平抗性;对噻虫嗪(RR=24.9~146.5)产生中等水平至高水平抗性;对噻虫胺(RR=9.9~16.5)、呋虫胺(RR=13.5~15.9)、乙虫腈(RR=18.3~60.4)、毒死蜱(RR=17.4~29.8)、异丙威(RR=13.9~46.0)产生中等水平抗性;对啶虫脒(RR=5.1~9.9)产生低水平抗性;对噻虫啉(RR=3.9~7.1)处于敏感至低水平抗性水平;对醚菊酯(RR=1.3~4.9)处于敏感水平。此外,褐飞虱对噻虫嗪、噻嗪酮抗性上升明显,同时褐飞虱对吡虫啉抗性也有上升的趋势。【结论】仍需暂停吡虫啉、噻嗪酮在水稻上防治稻飞虱,严格限制吡蚜酮在水稻上的使用次数;醚菊酯可作为吡虫啉、噻嗪酮和吡蚜酮的替代药剂或轮换药剂。     

抗吡虫啉棉蚜种群对吡蚜酮等药剂的交互抗性及施药对其生物学特性的影响

为了明确吡蚜酮对抗吡虫啉棉蚜Aphis gossypii种群的防治效果,提出抗吡虫啉棉蚜的治理策略,利用抗吡虫啉棉蚜种群(RF₂₇)、敏感种群(SS)和夏津田间种群(XJ),分别采用浸渍法、微量点滴法、生化测定法和系统观察法研究了棉蚜无翅成蚜对吡蚜酮等药剂的交互抗性及施药对其生物学特性的影响。结果表明: 吡蚜酮对RF₂₇,XJ和SS的LD₅₀分别为1.213×10^-5,8.506×10^-5和5.140×10^-5 μg/头,RF₂₇对吡蚜酮表现出明显的负交互抗性现象。RF₂₇对啶虫脒、烯啶虫胺和噻嗪酮分别产生2.35,2.98和1.71倍的抗性。RF₂₇的羧酸酯酶和谷胱甘肽-S-转移酶的比活力较SS分别高2.73和1.57倍,说明羧酸酯酶和谷胱甘肽-S-转移酶比活力的提高是引起棉蚜对吡虫啉产生抗性的重要原因之一。吡蚜酮分别处理RF₂₇,XJ和SS,其羧酸酯酶和谷胱甘肽-S-转移酶均受到显著抑制。吡蚜酮以低剂量处理RF₂₇成蚜,对其生长发育有显著的不利影响,表现为若蚜存活率降低(64.60%),净生殖率降低（10.39）,内禀增长率和周限增长率显著降低(分别为0.21和1.23),世代历期延长（10.87 d）,相对适合度较小（仅为0.70）。这些结果表明吡蚜酮在棉蚜防治中具有很高的应用价值。     

惠州地区褐飞虱对几种药剂的抗药性监测

2009年采用稻茎浸渍法测定广东省惠州地区褐飞虱Nilaparvata lugens(Stl)种群对吡虫啉、噻嗪酮、异丙威、丁烯氟虫腈、烯定虫胺和毒死蜱等杀虫剂的敏感性,测定结果表明:当地褐飞虱种群对吡虫啉产生了极高水平抗性(抗性倍数为422.2倍),对噻嗪酮、异丙威产生了中等水平抗性(抗性倍数分别为11.0和14.0倍),对丁烯氟虫腈仍处于敏感性降低(抗性倍数为3.7倍),对烯定虫胺和毒死蜱敏感(抗性倍数<3倍)。基于褐飞虱对这6种药剂抗性的明显差异,对田间治理褐飞虱合理使用药剂进行了讨论。     

甜菜夜蛾对虫酰肼的抗性选育、风险评估及交互抗性

虫酰肼是目前防治甜菜夜蛾Spodoptera exigua（Hübner）的一种主要杀虫剂,为评估其抗性风险,在室内进行了抗性筛选和交互抗性的研究。采用饲料感染法,在甜菜夜蛾饲养75代期间用虫酰肼筛选62代,与起始种群相比抗性上升39.2倍,与室内敏感品系相比抗性上升141.3倍。在筛选的早、中、后期,现实遗传力h²分别为0.1075（F₀～F₂₅）、0.2780（F₂₆～F₅₀）和0.0538（F₅₁～F₇₅）,整个筛选62代现实遗传力为0.1556。抗性种群筛选43次（F55）后停止用药筛选,饲养21代后,与敏感品系相比,抗性水平由63.5倍下降到21倍,抗性下降3倍。说明甜菜夜蛾具有对虫酰肼产生抗性的风险,且抗性衰退缓慢,短期内很难恢复到敏感水平。交互抗性测定结果表明,上述室内选育的抗性品系对甲氧虫酰肼具有71.4倍的高水平交互抗性,对阿维菌素具有13.1倍的中等水平交互抗性,对甲维盐、茚虫威和呋喃虫酰肼分别具有7.0、8.4和4.7倍的低水平交互抗性,但对溴虫腈交互抗性不明显（1.9倍）。结果提示： 间断交替使用虫酰肼可以延缓抗性的发展,但除溴虫腈外,虫酰肼和其他几种新型杀虫剂之间的轮用可能不是甜菜夜蛾抗性治理的有效策略。     

稻田节肢动物群落的多样性及对褐飞虱的控制功能

对江苏江浦及安徽安庆两地五种类型稻田的节肢动物群落生物多样性研究表明,以对褐飞虱Nilaparvata lugens具有抗性的粳稻田多样性指数最高。稻田蜘蛛亚群落与褐飞虱种群数量变化间存在明显的相关性,11年中64%的年份表现为显著相关。利用天敌功能指数EF=（E+P）^E/P、数值反应的方法研究了稻田蜘蛛功能团与褐飞虱种群间的生存、繁殖和数量关系,结果表明,初始EF值与褐飞虱对水稻的危害率及褐飞虱种群的未来最大饱和容量K值间呈显著相关。本文讨论了利用初始EF值来预测天敌对害虫的功能作用及生物防治与化学防治协调的可能性。     

Extracellular acidification elicits a chloride current that shares characteristics with ICl(swell)

A Cl^– current activated by extracellular acidification, I_Cl(pHac), has been characterized in various mammalian cell types. Many of the properties of I_Cl(pHac) are similar to those of the cell swelling-activated Cl^– current I_Cl(swell): ion selectivity (I^– > Br^– > Cl^– > F^–), pharmacology [I_Cl(pHac) is inhibited by 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS), 1,9-dideoxyforskolin (DDFSK), diphenylamine-2-carboxylic acid (DPC), and niflumic acid], lack of dependence on intra- or extracellular Ca²⁺, and presence in all cell types tested. I_Cl(pHac) differs from I_Cl(swell) in three aspects: 1) its rate of activation and inactivation is very much more rapid, currents reaching a maximum in seconds rather than minutes; 2) it exhibits a slow voltage-dependent activation in contrast to the fast voltage-dependent activation and time- and voltage-dependent inactivation observed for I_Cl(swell); and 3) it shows a more pronounced outward rectification. Despite these differences, study of the transition between the two currents strongly suggests that I_Cl(swell) and I_Cl(pHac) are related and that extracellular acidification reflects a novel stimulus for activating I_Cl(swell) that, additionally, alters the biophysical properties of the channel. cell swelling-activated chloride current; patch clamp; pH     

Mechanical signals and mechanosensitive modulation of intracellular [Ca(2+)] in smooth muscle

We testedthe hypothesis that strain is the primary mechanical signal in themechanosensitive modulation of intracellular Ca²⁺concentration ([Ca²⁺]_i) in airway smoothmuscle. We found that [Ca²⁺]_i wassignificantly correlated with muscle length during isotonic shorteningagainst 20% isometric force (F_iso). When the isotonic loadwas changed to 50% F_iso, data points from the 20 and 50% F_iso experiments overlapped in thelength-[Ca²⁺]_i relationship. Similarly, datapoints from the 80% F_iso experiments clustered near thosefrom the 50% F_iso experiments. Therefore, despite 2.5- and4-fold differences in external load, [Ca²⁺]_idid not deviate much from the length-[Ca²⁺]_irelation that fitted the 20% F_iso data. Maximal inhibition of sarcoplasmic reticular (SR) Ca²⁺ uptake by 10 µMcyclopiazonic acid (CPA) did not significantly change[Ca²⁺]_i in carbachol-induced isometriccontractions and isotonic shortening. CPA also did not significantlychange myosin light-chain phosphorylation or force redevelopment whencarbachol-activated muscle strips were quickly released from optimallength (L_o) to 0.5 L_o. These results are consistent with thehypothesis and suggest that SR Ca²⁺ uptake is not theunderlying mechanism.

     

The influence of vertical mixing on the photoinhibition of variable chlorophyll a fluorescence and its inclusion in a model of phytoplankton photosynthesis

The maximum effective quantum yield of photosystem II was estimatedfrom measurements of variable chlorophyll a fluorescence [(F'_m- F'_o)/F'_m = F'_v/F'_m] in samples of phytoplankton collectedfrom various depths in Chaffey Reservoir, Australia. Duringstratified conditions, F'_v/F'_m showed depth-dependent decreasesas irradiance increased during the morning, and increases asirradiancereduced in the afternoon. Wind-induced mixing disrupted thediel pattern, but even under well-mixed conditions a verticalgradient in F'_v/F'_m remained. Differences in F'_v/F'_m valuesbetween samples incubated at fixed depths and unconstrainedlake samples enabled identification of the phytoplankton mixingdepth. Recovery of F'_v/F'_m was modelled as a function of timeand the degree of F'_v/F'_m inhibition, while damage was considereda function of photon dose. A combined, numerical model was fittedto diel sequences of F'_v/F'_m to estimate rate constants fordamage and repair. Recovery rate constants ranged from r = 0.7x 10^-4 to 9.1 x 10^-4 s^-1, while damage rate constants rangedfrom k = 0.03 to 0.22 m² mol photon^-1. A fluorescence-basedmodel of photosynthesis was used to investigate the effectsof wind speed, euphotic depth and mixed layer depth on photoinhibition.At different mixing rates, depth-integrated photosynthesis wasenhanced by up to 16% under the conditions tested, while increasesof 9% occurred between phytoplankton with different measureddamage and repair characteristics.     

Production of Oikopleura longicauda (Tunicata: Appendicularia) in Toyama Bay, southern Japan Sea

Oikopleura longicauda occurred throughout the year in ToyamaBay, southern Japan Sea, and analysis of its size compositionand maturity revealed that reproduction was continuous overtheyear. Somatic growth production (P_g) varied with season from0.03 to 103 mg carbon (C) m^–2day^–1 (annual P_g 4.5g C m^–2), and house production (P_e) from 0.11 to 266 mgC m^–2 day^–1 (annualP_e 11.3 g C m^–2). The annualP_g/B ratio was 176. Compared with production data of some predominantzooplankton species in Toyama Bay, it is suggested that despitetheir smaller biomass, appendicularians are an important secondaryproducer.     

影响叶螨磷酸酯酶活性的四因子数学模型

应用二次回归通用旋转组合设计,组建了影响叶螨磷酸酯酶（酸性和碱性）活性的四因子（缓冲液Ph值X₁、温浴时间X₂、反应温度X₃、底物浓度X₄）数学模型: Y_酸性=0.456380+0.107889X₂+0.069027X₃-0.026836X₁²-0.030794X₃², F=24.98,P<0.01;Y_碱性=0.267286-0.200736X₁+0.049541X₂+0.030930X₃-.049063X₁X₂+0.053585X₁²-0.049665X₂^2, F=57.68,P<0.01。结果表明,温浴时间是影响叶螨酸性磷酸酯酶活性的关键因子,在缓冲液pH 4.4、底物浓度8.5×10^-3 mol/L、42℃温浴40 min测得该酶活性最强。影响碱性磷酸酯酶活性的关键因子则是缓冲液pH值,pH 9.0、37℃恒温30 min、底物7.5×10^-3 mol/L的条件下,光密度值最大。两种酶的最大吸收峰波长为405 nm。     

Influence of group B streptococci on piglet pulmonary artery response to bradykinin

To study whether a sepsis-induced increase indes-Arg⁹-bradykinin(des-Arg⁹-BK) and bradykinin (BK)B₁-receptor activity participatesin the observed increase in pulmonary vascular resistance in neonatal group B streptococcal sepsis (GBS), isometric force bioassays ofpulmonary artery (PA) rings were studied, after 4-h exposure to eitherKrebs or GBS, by using the following protocols:1) BK dose-response curve,2) vascular response to BK withN^G-nitro-L-arginine methyl ester(L-NAME), and3) response todes-Arg⁹-BK (BK metabolite andB₁ agonist). PA rings exposed toBK resulted in contraction in the GBS group and a decrease in restingtension in the Control group (P = 0.034) at a concentration of10⁵ M. GBS-treated PA ringscontracted more to des-Arg⁹-BKthan did Controls (P < 0.001). BK(10⁶ M) relaxedpreconstricted PA rings incubated in GBS less than BK relaxed Controls(P < 0.001), and preincubation withL-NAME decreased relaxation inboth. These results suggest that GBS decreased endothelium-dependent BKrelaxation and increased contractile response todes-Arg⁹-BK. We speculate thatthis occurs secondary to upregulation of B₁ receptors reflected byB₁-agonist-mediated PA contraction.

     

Effects of microtubules and microfilaments on [Ca(2+)](i) and contractility in a reconstituted fibroblast fiber

We used a reconstituted fiber formed when 3T3fibroblasts are grown in collagen to characterize nonmusclecontractility and Ca²⁺ signaling. Calf serum (CS) andthrombin elicited reversible contractures repeatable for >8 h. CSelicited dose-dependent increases in isometric force; 30% produced thelargest forces of 106 ± 12 µN (n = 30), whichis estimated to be 0.5 mN/mm² cell cross-sectionalarea. Half times for contraction and relaxation were 4.7 ± 0.3 and 3.1 ± 0.3 min at 37°C. With imposition of constant shortening velocities, force declined with time, yieldingtime-dependent force-velocity relations. Forces at 5 s fit thehyperbolic Hill equation; maximum velocity(V_max) was 0.035 ± 0.002 L_o/s.Compliance averaged 0.0076 ± 0.0006 L_o/F_o. Disruption of microtubules with nocodazole in a CS-contracted fiber had no net effects on force, V_max, or stiffness; force increased in 8, butdecreased in 13, fibers. Nocodazole did not affect baselineintracellular Ca²⁺ concentration([Ca²⁺]_i) but reduced (~30%) the[Ca²⁺]_i response to CS. The force afternocodazole treatment was the primary determinant of stiffness andV_max, suggesting that microtubules were not amajor component of fiber internal mechanical resistance. Cytochalasin Dhad major inhibitory effects on all contractile parameters measured butlittle effect on [Ca²⁺]_i.