抗青枯病花生种质资源的鉴定与筛选

为筛选适宜河南省信阳市种植的抗青枯病花生品种,对27份花生品种青枯病田间病圃进行鉴定,计算其发病率和病情指数,从而进行抗病性鉴定和筛选。结果表明,27个供试品种中,中高抗品种共10个占总数的37%,3个品种类型各筛选出2个抗病品种。6个抗病品种发病规律表明,7天和14天病情指数增长较快,21天后基本无变化。高油型花生‘远杂9102’和‘信花425’,高油酸型花生‘信花14号’和‘驻花11号’,普通型花生‘远杂21号’和‘豫花149号’为适宜信阳种植的抗病品种。     

Bacteria and antibiotic resistance detection in fractures of wild birds from wildlife rehabilitation centres in Spain

Anatomic adaptations make birds more prone to open fractures with exposed bone parts losing vascularization. As a result of this exposure, fractures are colonized by different microorganisms, including different types of bacteria, both aerobic and anaerobic, causing osteomyelitis in many cases. For this reason, antibiotic treatment is common. However, carrying out antibiotic treatment without carrying out a previous antibiogram may contribute to increased resistance against antibiotics, especially in migratory wild birds. In this paper, bacterial counts regarding fracture type, bacterial identification and antibiotic resistance have been analysed in wild birds from wildlife rehabilitation centres in Spain. The results obtained showed that open fractures had higher bacterial counts (CFU/mL) than closed ones. Bacteria in family Enterobacteriaceae, identified were Escherichia spp., Enterobacter spp., Shigella spp., Hafnia alvei, Proteus mirabilis, Leclercia adecarboxylata and Pantoea agglomerans. Other bacteria present in wild birds’ fractures were Aeromonas spp., Enterococcus spp. Bacillus wiedmannii and Staphylococcus sciuri. All species found presented resistance to at least one of the antibiotics used. Wild birds can be implicated in the introduction, maintenance and global spreading of antibiotic resistant bacteria and represent an emerging public health concern. Results obtained in this paper support the idea that it is necessary to take this fact into account before antibiotic administration to wild animals, since it could increase the number of bacteria resistant to antibiotics.     

遵义烟区不同海拔下植烟土壤细菌群落及影响因素分析

为探究不同海拔下植烟土壤细菌群落结构特征及影响细菌群落结构的主要因素,在贵州省遵义地区选择海拔800（ZL）、1000（ZS）和1200m（ZH）的3块植烟土壤,采用16S rRNA高通量测序法对植烟土壤微生物多样性进行分析。结果表明,ZL和ZH处理植烟土壤细菌α多样性均低于ZS处理;3个海拔下植烟土壤优势门为放线菌门（Actinobacteriota）、变形菌门（Proteobacteria）、绿弯菌门（Chloroflexi）和酸杆菌门（Acidobacteriota）,放线菌门的相对丰度以ZL处理最高,较ZH处理提高了34.22%;变形菌门表现则相反,ZH处理变形菌门丰度较ZL处理显著提高。绿弯菌门与酸杆菌门丰度在3个海拔处理中表现较为一致,均为ZS>ZL>ZH。聚类热图分析结果显示,土壤含水率和pH与Armatimonadota和蓝细菌门（Gyanobacteria）存在显著正相关关系,与变形菌门存在显著负相关关系;变形菌门、厚壁菌门（Firmicutes）和髌骨菌门（Patescibacteria）与土壤微生物量氮存在显著正相关关系,而与速效钾存在极显著负相关关系。     

细菌性根腐病对三七光合特性的影响

根腐病是严重威胁三七生产的重要因素之一,常年发病率在5%～20%。其中,由假单胞杆菌(Pseudomon adaceae)引起的细菌性根腐病,因叶片出现缺水萎蔫症状时才能发现,目前尚无有效的预防措施。为探究细菌性根腐病对三七光合生理特性的影响,从而为三七病害生理学研究提供理论基础,本文以2年生三七为材料,设置2个处理[发病植株和健康对照植株(CK)],研究细菌性根腐病对三七形态结构、光合特性和光系统功能的影响。结果表明:1)根腐病导致三七的主根褐变腐烂,须根断损,茎基部腐烂中空,叶片萎蔫,各器官含水量比CK显著降低(P≤0.05);而株高、叶面积和叶片解剖结构(上表皮厚度、下表皮厚度、栅栏组织厚度和海绵组织厚度)在两处理间均无显著差异。2)发病植株叶片叶绿素含量、净光合速率(P_n)、气孔导度(G_s)、水分利用效率(WUE)和表观叶肉导度(AMC)显著低于CK(P≤0.05),且CK叶片胞间CO_2浓度(C_i)与P_n呈反比。3)发病植株叶片的光系统Ⅰ(PSⅠ)反应中心P700最大荧光信号(P_m)根腐病初期暂不受影响,而叶片暗适应下最大量子效率(F_v/F_m)、光系统Ⅱ(PSⅡ)电子传递速率[ETR(Ⅱ)]、PSⅡ实际光化学量子产量[Y(Ⅱ)]、PSⅠ电子传递速率[ETR(Ⅰ)]、PSⅠ周围的环式电子流(CEF)和PSⅠ实际光化学量子产量[Y(Ⅰ)]均显著低于CK(P≤0.05);参与调节性能量耗散的量子产量[Y(NO)]则显著高于CK(P≤0.05);发病植株的快速叶绿素荧光动力学曲线上出现K相,且显著高于CK(P≤0.05)。总的来看,细菌性根腐病对三七发病植株各器官的损伤严重程度为根茎叶,且根腐病导致发病植株叶片叶绿素降解, PSⅡ受到不可逆损伤, PSⅠ的电子传递被抑制,且叶肉细胞CO_2的同化能力降低,根腐病限制三七正常进行光合作用的条件。     

Azospirillum brasilense mitigates water stress imposed by a vascular disease by increasing xylem vessel area and stem hydraulic conductivity in tomato

Water stress, with its negative consequences on plant growth and survival, can be mitigated by Azospirillum brasilense inoculation. In tomato, A. brasilense delays wilting caused by a vascular pathogen, Clavibacter michiganensis subsp. michiganensis, by yet unknown mechanisms. We studied morphological, anatomical and physiological changes induced by A. brasilense in tomato that relate to water stress tolerance, which could explain the deferral in symptom expression. For this purpose, tomato seeds were treated or not with A. brasilense BNM65, and 5 weeks later plants were challenged with C. michiganensis subsp. michiganensis or mock inoculated with water. There was a large growth promotion associated to Azospirillum: treated plants had higher total biomass and leaf area. In relation to water stress tolerance, Azospirillum treated plants had larger xylem vessel area, higher stem specific hydraulic conductivity, thicker stems, and lower shoot/root dry matter and specific leaf area. These changes were opposite to those induced by C. michiganensis subsp. michiganensis. We conclude that A. brasilense favoured a better adjustment of plant-water relations by several mechanisms, and thus, transitorily alleviated symptoms expression of a vascular disease.     

Breeding for increased grain protein and micronutrient content in wheat: Ten years of the GPC-B1 gene

To provide food and nutrition security for a growing world population, continued improvements in the yield and nutritional quality of agricultural crops will be required. Wheat is an important source of calories, protein and micronutrients and is thus a priority to breed for improvements in these traits. The GRAIN PROTEIN CONTENT-B1 (GPC-B1) gene is a positive regulator of nutrient translocation which increases protein, iron and zinc concentration in the wheat grain. In the ten years since it was cloned, the impacts of GPC-B1 allelic variation on quality and yield traits have been extensively analyzed in diverse genetic backgrounds in field studies spanning forty environments and seven countries. In this review, we compile data from twenty-five studies to summarize the impact of GPC-B1 allelic variation on fifty different traits. Taken together, the results demonstrate that the functional copy of the GPC-B1 gene is associated with consistent positive effects on grain protein, Fe and Zn content with only marginally negative impacts on yield. We conclude that the GPC-B1 gene has the potential to increase nutritional and end use quality in a wide range of modern cultivars and environments and discuss the possibilities for its application in wheat breeding.     

Resveratrol protects cortical neurons in infant rats with bacterial meningitis through miR-223-3p/NLRP3 pathway

AIM To investigate the protective effect of resveratrol (Res) on cortical neurons in rat bacterial meningitis (BM) model. METHODS Group B hemolytic Streptococcus was injected via the posterior cistern to establish a BM model. Resveratrol was administered intranasally and microRNA-223-3p (miR-223-3p) antagomir was administered by intracerebroventricular injection. HE staining was used to observe the pathological changes of the brain tissue. Loeffler scoring method was used to evaluate the neurobehavioral functions. TUNEL staining was used to detect neuronal apoptosis. The expression of interleukin-1β (IL-1β), IL-18, glial fibrillary acidic protein (GFAP) and ionized calcium-binding adaptor molecule 1 (Iba1) was detected by immunofluorescence staining. The protein levels of nucleotide-binding oligomerization domain-like receptor protein 3 （NLRP3）, cleaved caspase-1, IL-1β and IL-18 were determined by Western blot. The expression level of miR-223-3p was detected by RT-qPCR. Online software TargetScan was used to search for the complementary nucleotide sequences between miR-223-3p and NLRP3 mRNA. RESULTS Compared with sham group, the thickness of meninges in BM model was increased, the neurological score was decreased (P<0.05), and the number of TUNEL positive neurons was increased significantly (P<0.05). Astrocytes and microglia were activated, the fluorescence intensity of IL-1β and IL-18 was increased (P<0.05), and the expression levels of NLRP3, cleaved caspase-1, IL-1β, IL-18 and miR-223-3p were increased (P<0.05). Compared with BM group, after treatment with resveratrol, the neurological score was increased (P<0.05), the number of TUNEL positive neurons was decreased significantly (P<0.05), and the inflammatory response of astrocytes and microglia was suppressed. The fluorescence intensity of IL-1β and IL-18 was decreased (P<0.05), the protein levels of NLRP3, cleaved caspase-1, IL-1β and IL-18 were decreased (P<0.05), and the expression level of miR-223-3p was increased (P<0.05). A nucleotide sequence in the 3'-UTR of NLRP3 mRNA might be targeted by miR-223-3p. In the brain of rat BM model, compared with antagomir control group, the expression of NLRP3 was increased in miR-223-3p antagomir group with resveratrol treatment (P<0.05). CONCLUSION Resveratrol may reduce the inflammatory death of cortical neurons in BM model of infant rats through miR-223-3p/NLRP3 pathway, thus playing a protective role for the neurons.     

布氏乳杆菌和甲酸对青藏高原不同物候期燕麦青贮饲料发酵品质和细菌群落的影响

为探讨布氏乳杆菌和甲酸对青藏高原不同物候期燕麦（Avena sativa L.）青贮饲料发酵品质和细菌群落的影响，本试验以开花期、乳熟期和蜡熟期燕麦为原料，设置对照、添加甲酸和添加布氏乳杆菌3个处理，青贮90 d后，测定其营养成分、发酵指标和细菌群落组成。结果表明：布氏乳杆菌和甲酸处理均改变不同物候期燕麦青贮饲料中细菌群落组成（P<0.05），并提高其乳酸细菌相对丰富度；与对照相比，用布氏乳杆菌和甲酸处理不同物候期的燕麦青贮后，蜡熟期的燕麦pH值降低（P<0.05），乙酸均增加9.7%，丙酸分别降低11.6%和8.6%，氨态氮分别降低11.3%和19.2%。综合细菌群落组成、发酵品质和营养成分来看，蜡熟期的燕麦添加布氏乳杆菌和甲酸后，其青贮品质较佳。     

凡纳滨对虾养殖体系中群体感应淬灭菌的筛选、安全性评估及发酵条件优化

从凡纳滨对虾(Litopenaeus vannamai)养殖体系中筛选得到具有群体感应淬灭(Quorum quenching, QQ)活性的潜在功能菌，并对菌株进行16S rDNA鉴定、安全性评估及发酵条件优化。采用根癌农杆菌(Agrobacterium tumefaciens) A136液体X-gal法进行活性菌株筛选，发现2株细菌(BDZ5和W1B)的发酵液对信号分子己酰基高丝氨酸内酯(C6-HSL)具有显著的降解作用，但经沸水浴处理后均丧失降解活性。经16S rDNA基因序列分析，菌株BDZ5和W1B分别被鉴定为芽孢杆菌属(Bacillus)和科贝特氏菌属(Cobetia)。安全性评估结果显示，菌株BDZ5和W1B均无溶血性，且对多数抗生素具有敏感性，注射2株活性菌未提高凡纳滨对虾死亡率，且对凡纳滨对虾血清免疫酶活性无显著影响。单因素条件优化结果显示，在起始pH为7.0、盐度为20、0.0005%的MnCl2条件下培养48 h后，菌株BDZ5达到最大生长量；在起始pH为6.0、盐度为40、0.05%的CaCl2条件下培养48 h，菌株W1B达到最大生长量。2株菌的最适信号分子C6-HSL降解条件与其生长条件有所不同，在起始pH为7.5、盐度为30、0.0005%的MnCl2条件下培养48 h，2株活性菌对信号分子C6-HSL的降解率达到最大值。研究表明，菌株BDZ5和W1B可作为益生菌应用于水产养殖，为基于QQ角度防治对虾细菌性病害提供优良菌种。     

咸干蓝点马鲛品质特征与优势菌群分析

为了更好地了解传统咸干蓝点马鲛(Scomberomorus niphonius)(鲅鱼)的品质特征，以市售产品中感官品质较为突出的咸干鲅鱼作为研究对象，对其水分、含盐量、NaNO2含量、挥发性盐基氮(TVB-N)、硫代巴比妥酸值(TBARS)等理化指标进行了测定，并进一步对咸干鲅鱼中的优势菌进行了分离、纯化与鉴定。结果显示，咸干鲅鱼样品含水量为54.40%、含盐量为3.1%，属于半干低盐制品；NaNO2含量为5.07 mg/kg，符合相关食品安全标准的规定；TVB-N含量高达40.12 mg/100 g，说明发酵过程蛋白质降解程度较大；TBARS值为10.00 mg/kg，脂质氧化程度在感官可接受的范围内。咸干鲅鱼中的微生物以细菌为主，清酒乳杆菌(Lactobacillus sakei)、产气肠杆菌(Enterobacter aerogenes)、长赖氨酸芽孢杆菌(Lysinibacillus macrolides)和香坊肠杆菌(Enterobacter xiangfangensis)为优势菌。其中，清酒乳杆菌具有发酵菌的典型特征，可能在咸干鲅鱼发酵过程中起主要作用。