不同种源的柠条锦鸡儿的生理特性与抗旱性

以内蒙赤峰、内蒙杭锦旗、山西武寨和宁夏盐池4种源的柠条锦鸡儿(Caragana korshinskii)为材料,在不同水分条件下对其叶片的净光合速率、蒸腾速率、气孔导度、胞间二氧化碳体积分数、水分利用效率和耐旱致死点进行测定.结果表明:各种源柠条在受到干旱胁迫时,光合速率明显下降,但内蒙赤峰种源明显表现出比其他种源光合效率高;蒸腾速率和气孔导度各种源都呈下降趋势,但在不同种源间变化规律性不明显;胞间二氧化碳体积分数基本与净光合速率成反比;水分利用效率变化规律不明显,但内蒙赤峰种源明显表现出比其他种源水分利用效率高.各种源的耐旱致死点依次为赤峰42.3 d＞杭锦旗41.7 d＞盐池38.7 d＞五寨31.0d,致死含水量依次为1.6%、1.8%、1.8%和1.9%.     

大肠埃希菌Ⅰ类整合子与多重耐药的相关性分析

采用从粪便中分离并鉴定出的40株鸡源大肠埃希氏菌,用K-B法测定大肠杆菌多重耐药性,通过PCR法扩增Ⅰ类整合子,电泳检测扩增产物。结果表明,40株大肠杆菌对10类18种抗菌药物的耐药率,最高为S,C,SMX,SXT 100%,最低为PB,CTX 0%,多重耐药率(耐3种以上药物)为100%。Ⅰ类整合子阳性菌株35株,阳性率87.5%。Ⅰ类整合子对大肠杆菌多重耐药性的产生和传播起着重要作用,应加强基因水平耐药监测。     

机械沙障抗拉力学特性研究——以临策铁路沿线高立式和平铺式沙障为例

为揭示机械沙障抗拉力学特性,优选合适的阻沙固沙材料,利用TY8000系列伺服控制机对试验对象进行纵向拉伸试验.结果表明:当孔隙度为均一型(全疏型或全密型)时,不同材料沙障的试样宽度与抗拉力均呈幂函数正相关,与抗拉强度呈幂函数负相关,其抗拉力与伸长量变化曲线均为单峰曲线;当材料相同时,不同孔隙度沙障的试样宽度与抗拉力均呈...     

Effects of increased ambient temperature and supplemental altrenogest before pregnancy establishment in gilts

Heat stress (HS) mitigation strategies are critically needed to combat the substantial economic effects on animal agriculture. The manifestations of seasonal infertility include delayed puberty onset, reduced conception rates, decreased litter size, and increased wean to estrus interval. To assess the effects of HS during early gestation and evaluate the benefit of supplemental altrenogest (ALT) as a mitigation strategy, 30 crossbred postpubertal gilts (157 ± 11 kg body weight) were subjected to estrous synchronization via 14 d oral administration of ALT. Artificial insemination during estrus was performed, and gilts were then placed into one of four treatment groups: HS (35 ± 1 °C for 12 h/31.60 ± 1 °C for 12 h) with (HSALT, n = 7) or without (HSCON, n = 7) 15 mg/d ALT supplementation or thermal neutral (TN; 20 ± 1 °C) conditions with (TNALT, n = 8) or without (TNCON, n = 8) 15 mg/d ALT supplementation until 12 d post-estrus (dpe). Administrating ALT occurred at 0600 hours from 3 to 12 dpe, and rectal temperatures (T_R) and respiration rates (RR) were recorded. Blood was collected via jugular venipuncture on 0, 4, 8, and 12 dpe. Gilts were euthanized humanely at 12 dpe followed by the collection of ovarian tissue, and uterine flushing for conceptus collection. In HS compared with TN gilts, RR and T_R were increased (P < 0.01) but unaffected by ALT supplementation. Feed intake was reduced (P < 0.01) by HS but unaltered by the ALT treatment. Corpora lutea (CL) weight was reduced (P < 0.01) in HSCON gilts when compared with TNCON and HSALT gilts despite progesterone concentrations in serum and luteal tissue not being affected by treatment (P ≥ 0.10). CL diameter was reduced (P ≤ 0.05) in HSALT gilts compared with other treatments. Interleukin-1β (IL1B) uterine flush concentration was not affected (P > 0.20) by environment or ALT supplementation, although moderate (P = 0.06) interaction between environment and ALT existed, as IL1B concentration in TNALT was increased (P = 0.03) compared with TNCON gilts. While environment did not affect conceptus development (P = 0.90), ALT supplementation advanced conceptus elongation (P < 0.01). Collectively, these data demonstrate that HS may affect luteal development before pregnancy establishment, and ALT increases conceptus elongation by 12 dpe.     

Proteomic profiling of plasma-derived small extracellular vesicles: a novel tool for understanding the systemic effects of tick burden in cattle

Cattle ticks pose a significant threat to the health and profitability of cattle herds globally. The investigation of factors leading to natural tick resistance in cattle is directed toward targeted breeding strategies that may combat cattle tick infestation on the genetic level. Exosomes (EXs), small extracellular vesicles (EVs) of 50 to 150 nm diameter, are released from all cell types into biofluids such as blood plasma and milk, have been successfully used in diagnostic and prognostic studies in humans, and can provide essential information regarding the overall health state of animals. Mass spectrometry (MS) is a highly sensitive proteomics application that can be used to identify proteins in a complex mixture and is particularly useful for biomarker development. In this proof of principle study, EXs were isolated from the blood plasma of cattle (Bos taurus) with high (HTR) and low tick resistance (LTR) (n = 3/group). Cattle were classified as HTR or LTR using a tick scoring system, and EXs isolated from the cattle blood plasma using an established protocol. EXs were subjected to MS analysis in data-dependent acquisition mode and protein search performed using Protein Pilot against the B. taurus proteome. A total of 490 unique proteins were identified across all samples. Of these, proteins present in all replicates from each group were selected for further analysis (HTR = 121; LTR = 130). Gene ontology analysis was performed using PANTHER GO online software tool. Proteins unique to HTR and LTR cattle were divided by protein class, of which 50% were associated with immunity/defense in the HTR group, whereas this protein class was not detected in EXs from LTR cattle. Similarly, unique proteins in HTR cattle were associated with B-cell activation, immunoglobins, immune response, and cellular iron ion homeostasis. In LTR cattle, unique exosomal proteins were associated with actin filament binding, purine nucleotide binding, plasma membrane protein complex, and carbohydrate derivative binding. This is the first study to demonstrate that MS analysis of EXs derived from the blood plasma of HTR and LTR cattle can be successfully applied to profile the systemic effects of tick burden.     

棉花幼苗对盐胁迫的生理响应与耐盐机理

为探究不同耐盐性棉花品种幼苗对盐胁迫的生理响应特征,以棉花耐盐品种中9806和盐敏感品种中S9612为材料,采用水培法,设置4个NaCl浓度梯度(0、100、150、200 mmol·L^-1)来模拟不同强度盐胁迫条件。结果表明:随着盐浓度的增加,各棉花品种的可溶性糖(SS)含量上升,抗氧化酶活性呈先上升后下降的趋势;盐处理下,耐盐品种可溶性蛋白(SP)、脯氨酸(Pro)含量增加量高于盐敏感品种;S1处理(100 mmol·L^-1 NaCl)中盐敏感品种丙二醛积累量较低,但在S2和S3处理(150、200 mmol·L^-1 NaCl)中,耐盐品种丙二醛含量增幅(5.35%~6.83%)低于盐敏感品种(36.93%~77.34%),超氧化物歧化酶(SOD)、过氧化物酶(POD)活性增加量较大;低盐浓度(S1处理)下,盐敏感品种地上部分能够保持较少的Na⁺,高盐浓度(S2和S3处理)下,耐盐品种根中Na⁺增加量小于盐敏感品种,茎中K⁺、K⁺/Na⁺较高。综上表明,耐盐品种棉花通过增强渗透调节,提高抗氧化酶活性缓解膜脂过氧化,维持较高K⁺/Na⁺,从而提高棉花幼苗的耐盐性。     

小麦赤霉病生防菌DZSG23的抗病机制

课题组前期从健康杜仲叶片中分离得到1株内生细菌枯草芽孢杆菌DZSG23,此菌可以较好地防控小麦赤霉病。为明确芽孢杆菌DZSG23在小麦中的定殖与强化抗病机制研究,利用抗生素标记法分析了DZSG23菌体在小麦组织中的定殖情况,采用荧光定量PCR技术检测不同生育期小麦穗部PR-1、AOS、ACOI等基因的表达水平变化。结果表明,DZSG23可在苗期小麦植株和小麦穗表面稳定定殖;DZSG23浇灌接种苗期小麦后的第34天,DZSG23在苗期小麦植株的根、茎和叶中的定殖量分别达到1.437×10⁶ CFU·g^-1、3.285×10³ CFU·g^-1和2.377×10³ CFU·g^-1;DZSG23喷施小麦穗表面15 d后,穗表面菌群密度仍可达7.146×10³ CFU·g^-1。此外,诱导系统抗性(ISR)信号通路研究表明,拮抗菌DZSG23可以诱导PR-1和AOS基因的上调表达,表明拮抗菌DZSG23引入小麦后可诱导小麦的水杨酸(SA)和茉莉酸(JA)信号通路,增强其抗病性。     

c-GMP诱导对盐胁迫下番茄的转录组分析

以市场常见的番茄为材料,采用Illumina高通量测序技术对NaCl胁迫、c-GMP诱导以及两者组合处理下番茄幼苗进行转录组测序。结果表明:共获得83.35 Gb的原始数据,Q30碱基百分比在90.91%及以上,分别将各样品的原始读数与指定的参考基因组进行序列比对,比对效率从88.03%到92.74%不等。同时将得到的31 734条序列注释到不同的数据库(GO、KEGG、KOG、NR、Pfam、Swiss-Prot和egg NOG),通过GO数据库,将其划分到细胞组分、分子功能以及生物学过程三大注释类别下的51个亚功能组中,通过COG数据库与KEGG数据库将其分别注释到25个类别与128个代谢通路。在NaCl胁迫、c-GMP诱导以及两者组合处理下共发现SNP位点127 944个,其中仅有22.6%的SNP位点位于非编码区。差异基因结果显示,c-GMP能诱导盐胁迫下更多基因的表达。该转录组测序数据可靠,结果覆盖面广,为番茄c-GMP诱导盐胁迫下基因挖掘与功能研究提供了理论依据。     

103份小麦品种（系）抗条锈性和遗传多样性评价及基因检测

【目的】了解小麦品种（系）对条锈病的抗性水平及遗传多样性,掌握条锈病抗性基因的利用情况,为培育和合理利用优良小麦抗条锈病新品种提供理论依据。【方法】选用小麦条锈病流行生理小种CYR32、CYR33和CYR34对103份小麦品种（系）进行苗期抗条锈病分小种鉴定、成株期抗CYR32鉴定,并利用SSR分子标记对其进行遗传多样性分析,进而利用已知小麦抗条锈病基因Yr5、Yr9、Yr10、Yr15、Yr18和Yr26的分子标记进行抗条锈病基因检测。【结果】苗期抗性鉴定表明,103份小麦品种（系）对生理小种CYR32表现为抗病的有20份,占供试材料的19.42%;有34份品种（系）对CYR33表现为抗病,占供试材料的33.01%;36份品种（系）对CYR34表现为抗病,占供试材料的34.95%;仅有郑6辐、宁麦3号、老兰麦、京411、京作278、扬麦158共6个品种对生理小种CYR32、CYR33和CYR34均表现抗病。成株期对CYR32抗性鉴定表明郑州021等55份材料表现为成株期抗性,占供试材料的53.40%。遗传多样性分析表明,103份小麦品种（系）的遗传相似系数变异范围为0.50—0.93,平均值为0.66。103份小麦品种（系）聚类分析可分为3大类,第Ⅰ类包含4个品种,分别为花培112-2、尤皮2号、鲁沾1号和Elkhart;第Ⅱ类包含43个品种（系）,其中来自于同一地区的品种（系）或含系谱来源相同的品种（系）聚在一类,说明小麦品种之间的亲缘关系与品种来源有很大的关系;第Ⅲ大类中具有相同系谱的品种（系）都聚在一个亚类,表明同一地区小麦生产品种选育过程中多数使用了相同或亲缘关系相近的材料,导致小麦育成品种之间遗传关系相近。已知抗病基因检测到含有Yr9、Yr10、Yr18和Yr26特征带的品种（系）分别有15、8、19和1份,未检测到含有Yr5和Yr15阳性条带的品种（系）。【结论】供试小麦品种（系）苗期的抗性水平较低,郑6辐、宁麦3号、老兰麦、京411、京作278、扬麦158这6份品种可能含有未知全生育期抗病基因,适用于品种轮换种植防控小麦条锈病;成株期抗性较好,抗性基因检测Yr18使用频率较高。因此,小麦育种工作应充分利用优质已知抗性基因资源,发掘新抗性材料,培育多基因聚合的持久抗性品种。     

智能化纳米释药系统用于细菌感染治疗的研究进展

细菌耐药性的相关研究已成为多学科交叉研究的热点,纳米技术因其独特的物化性质在药物递送系统(drug delivery systems,DDSs)的应用中具有可以改善药物的药代动力学和药效学特性,为应对全球细菌抗生素耐药性问题提供了一种新的策略。作为药物载体,理想的纳米粒子必须具有较高的载药量,将药物运送到特定的病理部位和(或)靶细胞,同时不发生药物泄漏,并且在作用部位迅速释放药物。为此,人们积极寻求各种"智能"纳米释药系统,这种纳米释药系统可以对内部或外部刺激(如pH、氧化还原、温度、磁和光等)进行响应,从而实现对药物的可控释放。本文围绕pH、温度、光照以及酶和其他内源或外源因子刺激响应的智能化抗菌药物递送系统领域的最新研究进展进行了评述。