地衣芽孢杆菌W10与化学药剂复配对桃褐腐病菌抑制活性的增效作用

为减少化学药剂的使用,明确生防细菌地衣芽孢杆菌W10与化学药剂复配对桃褐腐病菌Monilinia fructicola抑菌活性的增效作用,采用菌落直径抑制法,检测W10菌液和抗菌蛋白与化学试剂复配的抑菌效果。结果显示,W10抗菌蛋白与化学药剂复配增效显著,与多菌灵100∶1增效作用最大(SR=4.32)。证明生防细菌W10菌液及抗菌蛋白与化学药剂以合适比例复配对桃褐腐病菌的抑制有增效作用,可用于该病害的防治。     

热水处理对金柑果实采后腐烂及生理特性的影响

金柑是果皮和果肉同食的柑果类型,对采后处理要求极为严格。该研究以金柑(Fortunella crassifolia)为材料,研究了其经30、40和50℃热水浸泡后果实的腐烂率、失重率、可溶性固形物、硬度、有机酸、细胞渗透率以及抗氧化酶活性变化。结果表明:经30℃热水处理5 min的果实失重率高于对照,而经40℃和50℃处理的果实失重率低于对照或差异不显著。经热水处理的果实总酸含量略低于对照,可溶性固形物含量在18%上下波动且差异不显著。热水处理可提高果实硬度,降低贮藏前期果实细胞渗透率以及贮藏过程中果实过氧化物酶和超氧化物歧化酶活性,激发过氧化氢含量升高,可有效降低贮藏过程中金柑果实腐烂率,但不同采收期的金柑所需的热水处理温度和时间不同。对于1月初采收的果实,处理时间为5 min或10 min可降低果实腐烂率;2月初采收的果实,40℃或50℃热水处理10 min可有效降低果实腐烂率;3月初采收的果实,当处理温度达到50℃,处理时间达到10 min,才可有效降低果实腐烂率,且对果实品质没有明显的不利影响。     

柑橘精油及壳聚糖复合处理对橄榄果实采后生理和耐贮性的影响

为探究柑橘精油(0.25%、0.75%、1.5%)和壳聚糖(0.25%、0.75%、1.5%)复合处理对橄榄(Canarium album)果实采后生理和耐贮性的影响，以鲜食橄榄品种(系)‘檀香’、‘梅埔2号’为材料，对采后贮藏期间的腐烂率、褐变指数、相对电导率、呼吸强度、丙二醛含量、内源抗氧化物质谷胱甘肽含量、过氧化物酶(POD)、抗坏血酸过氧化物酶(APX)活性进行测定，筛选橄榄果实复合保鲜剂的最佳浓度组合。结果表明，与对照相比，所有柑橘精油和壳聚糖复合处理均可有效降低橄榄果实在贮藏期间腐烂率、褐变指数和丙二醛的积累，抑制呼吸作用，保持较高的内源抗氧化物质谷胱甘肽含量和POD、APX活性。因此柑橘精油及壳聚糖处理能够有效延长橄榄果实的保鲜时间，提高耐贮性，其中以1.5%柑橘精油和1.5%壳聚糖组合的保鲜效果最佳。     

O2和CO2配比对低温贮藏李品质及生理变化的影响

为了探索适宜‘黑宝石’李贮藏的气体参数,研究了不同气体成分(6.0%O2+5.0%CO2、6.0%O2+1.0%CO2、10.0%O2+5.0%CO2和10.0%O2+1.0%CO2)处理对贮藏及货架期‘黑宝石’李采后品质(硬度、总糖、可滴定酸和腐烂指数)、抗氧化酶(SOD、POD和CAT)活性及MDA含量的影响。结果显示:(1)在贮藏0~45 d期间,冷藏对照果实的腐烂指数在8%以下,其货架果实的硬度仍可下降;贮藏至75 d时,冷藏对照果实的腐烂指数达38%,而且其果实失去了软化能力。(2)气调处理可减缓低温贮藏李果实硬度的下降,降低果实的腐烂指数,维持货架果实的后熟能力,但6.0%O2+1.0%CO2处理对果实腐烂指数的影响不显著。(3)气调处理可提高低温贮藏李果实的SOD、POD和CAT活性,抑制这3种酶在货架模拟过程中的升高,且可降低低温贮藏及货架期果实的MDA含量。(4)气调贮藏中以6.0%O2+5.0%CO2处理的效果最佳,果实的贮藏期可达75 d。研究说明,常规冷藏(0~1.5℃)可满足‘黑宝石’李果实采后短期贮藏(<45 d)的需要,而适宜的气调贮藏可使其贮藏期限延长30 d左右。     

采前二氧化氯处理对‘海沃德’猕猴桃的防腐保鲜效果

研究了采前二氧化氯（ClO2）处理对采后‘海沃德’猕猴桃果实在冷藏条件下的防腐保鲜效果。分别用浓度（有效成分）为0、20、40、60、80mg·L-1的ClO2溶液,在采收前对果实进行喷布处理,在采收后冷藏过程中定期测定相关生理指标,并在贮藏末期（120d）观察统计其腐烂指数。结果表明,浓度60mg·L-1的ClO2采前处理可有效清除猕猴桃果实表面菌落,并能显著延缓冷藏期间果实硬度的下降、抑制可溶性固型物的上升、降低猕猴桃呼吸速率、乙烯释放速率、失重和腐烂指数,提高过氧化物酶（POD）和苯丙氨酸解氨酶（PAL）的活性。通过比较,确定采前ClO2处理的适宜浓度为60mg·L-1。该浓度的ClO2处理对‘海沃德’猕猴桃具有明显的防腐保鲜效果,可有效延长贮藏期。     

火龙果致腐菌的分离鉴定及生物拮抗防腐措施

【背景】红心火龙果在常温下贮藏3 d鳞片就会出现黄化、萎蔫、果柄发霉,贮藏8 d果实腐烂率高于55%,贮藏16d果实腐烂率达95.5%以上。【目的】对红心火龙果主要致腐微生物进行分离鉴定,并筛选出防腐效果最佳的拮抗菌株。【方法】采用传统纯培养法对红心火龙果的致腐微生物进行分离纯化;通过致腐菌回接火龙果试验,找出主要致腐菌;通过形态学鉴定、细菌16S rRNA基因和真菌的rDNA ITS鉴定、生物信息学分析对主要致腐微生物进行初步鉴定;利用11株芽孢杆菌作为供试拮抗菌株对火龙果进行生物防腐。【结果】从自然腐烂红心火龙果上共分离得到60株致腐菌,其中细菌占38.33%,真菌占61.67%。将60株致腐菌回接红心火龙果,常温贮藏27 d后发现有2株致腐菌导致火龙果腐烂率达100%。经鉴定为扩展青霉(P. expansum)和黑附球菌(E. nigrum),分别命名为BP15和BP25。经平板拮抗试验显示:解淀粉芽孢杆菌10075对菌株BP15和BP25的抑制率最显著,抑制率分别为60.59%和84.73%。采用稀释浓度为90%的10075过滤除菌上清液对BP15和BP25进行抑制,其抑制率分别为54.32%和90.00%,而上清液热处理后对BP15和BP25的抑制率分别降低1.30%和12.43%。以稀释浓度为90%的10075过滤除菌上清液喷涂火龙果,处理10 d的防腐效果均高于30%。【结论】火龙果具有极高的经济价值、营养价值和药用价值,其在常温下容易腐烂。研究可为火龙果常温贮藏保鲜提供一种有效的生物防腐方法。     

采后预温处理对草莓果实贮藏保鲜效果的影响

研究了采后预温处理对草莓果实贮藏保鲜的影响,结果表明,冷藏(5℃)条件下,贮前50℃预热处理30m in的果实腐烂率最低;室温贮藏(19℃~21℃)条件下,50℃预热处理30m in、5℃预冷处理30m in的果实腐烂率最低;贮藏前期,果实中超氧化物歧化酶(SOD)活性、丙二醛(MDA)含量不断上升,预热处理能明显提高果实的SOD活性;贮藏后期,果实SOD活性不断下降、MDA含量持续上升,预处理能显著抑制果实SOD活性的下降和MDA含量的增加。     

三个产地猕猴桃品种‘金梅’在低温贮藏及货架期内的采后生理和品质变化

以湖北武汉、湖南花垣和贵州大方3个不同产地的中华猕猴桃(Actinidia chinensis Planch.)黄肉新品种‘金梅’果实为材料,对‘金梅’果实在低温贮藏和常温货架期内的生理特征和品质变化规律进行研究。结果显示:3个产地‘金梅’的果实硬度均在低温贮藏12周后快速下降至可食用硬度水平;而可溶性固形物含量(SSC)和总糖含量均表现为先快速上升然后稳定在较高水平,其中大方果实的SSC和总糖含量仅低温贮藏3周后就较早上升到稳定水平,但低于武汉和花垣的果实。3地‘金梅’果实中总酸含量则在较小的范围内波动,在武汉、花垣和大方产的软熟果实中含量依次降低。3地‘金梅’果实中维生素C含量约在70～90 mg/100 g鲜重范围内小幅波动,其中花垣‘金梅’维生素C含量整体较低。3地‘金梅’果实在低温贮藏过程中均表现出较高的失重率和较低的腐烂率,其中大方果实失重率低于武汉和花垣,但其较早出现较高的腐烂率。花垣和大方‘金梅’果实在分别低温贮藏4、12、20周后转入到常温货架期的寿命可达4、3、2周之久;其中,大方‘金梅’较早较快软熟,并且其SSC含量明显低于花垣‘金梅’。研究结果表明3地‘金梅’均表现出较好的耐贮性和较长的货架期,其中花垣‘金梅’表现出较好的果实综合品质,可能与其干物质含量较高有关。     

采前6-苄基腺嘌呤处理对葡萄品质和贮藏生理特性的影响

以‘红地球’葡萄和‘克瑞森无核’葡萄为试材,研究了采前6-苄基腺嘌呤（6-BA）处理对果实采收时的品质及采后贮藏特性的影响。结果表明,采前20mg·L-1 6-BA处理可以显著提高两种葡萄果实单粒重和单穗重,有效控制贮藏过程中果实腐烂与落粒,显著抑制葡萄的呼吸速率,维持果实硬度,延缓可滴定酸的下降,提高贮藏期间可溶性固形物的含量,抑制果实细胞膜透性的增加,保持细胞膜的完整性,提高葡萄的贮藏品质。     

果实成熟度和贮藏条件对枇杷种子无菌萌发的影响

为探讨影响枇杷(Eriobotrya japonica Lindl.)种子萌发的因素,将种子播种于1/2MS培养基80 d,研究了成熟度和贮藏条件对枇杷种子萌发的影响。结果表明,‘软条白沙’、‘宁海白’、‘塘科白沙’和‘大红袍’转色期和完熟期采收的种子的萌发率和苗高无显著差异;而‘大房’完熟期采收种子的萌发率较高。‘洛阳青’枇杷果实或种子经4℃贮藏5 d和10 d,萌发率和苗高与未贮藏种子的无显著差异,而贮藏期达20 d或更长时,贮藏种子的萌发率和苗高显著下降。在不同温度下贮藏的枇杷种子萌发率和苗高存在差异,‘早钟6号’和‘太平白’枇杷在15℃和4℃的优于25℃的,但适宜贮藏时间分别不超过15 d和30 d。因此,在转色期采收果实以及适度贮藏果实或种子可以保持枇杷种子的萌发能力。     

Antibacterial and antifungal lysozyme-type activity in Cameraria ohridella pupae

Lysozyme-type antibacterial and antifungal activity in pupae of Cameraria ohridella was studied. Activity against Micrococcus luteus and Bacillus megaterium was detected in pupae extract. Also antifungal activity from C. ohridella pupae extract directed against Saccharomyces cerevisiae strain W 303 was shown. During immunoblotting two bands in pupae extract, with molecular mass of about 15 and 28 kDa were recognized by antibodies directed against HEWL. After acid electrophoresis followed by bioautography of the extract, two lytic zones showing lysozyme-type activity against M. luteus were observed. Two bacteria: Gram-positive Aerococcus viridans and Gram-negative Aeromonas salmonicida ssp. masoucida were isolated from pupae of C. ohridella. Their activity against M. luteus, B. megaterium, and S. cerevisiae W303 was detected. After immunoblotting with antibodies against HEWL, also two proteins from bacterial suspensions of A. viridans and A. salmonicida were detected, about 15 and 28 kDa.     

地衣芽胞杆菌对实验性家兔阴道炎影响的研究

目的通过探讨地衣芽胞杆菌活菌制剂对实验性家兔细菌性阴道病的影响,恢复家兔阴道微生态平衡和正常菌群环境。方法（1）采用注射用氨苄西林和甲硝唑生理盐水溶液注入家兔阴道进行冲洗,建立家兔阴道脱污染动物模型。（2）取40只阴道脱污染家兔,其中20只接种大肠埃希菌,20只接种金黄色葡萄球菌,建立家兔阴道感染模型。（3）地衣芽胞杆菌对家兔阴道菌群失调的调整作用：采用不同浓度的地衣芽胞杆菌菌液（10^6CFU／ml、10^8CFU／ml、10^9CFU／ml）对感染家免阴道进行接种,分析和考察地衣芽胞杆菌对家兔阴道菌群失调的影响以及对家兔阴道黏膜的影响。结果（1）动物经过金黄色葡萄球菌感染,通过地衣芽胞杆菌治疗后,动物阴道内芽胞杆菌、肠杆菌、乳杆菌数量明显上升,葡萄球菌数量明显下降,自细胞数量减少,黏膜红肿减轻、分泌物减少,治疗作用明显。（2）大肠埃希菌感染动物经地衣芽胞杆菌治疗后,动物阴道内芽胞杆菌、乳杆菌数量明显上升,肠杆菌数量明显降低,白细胞数量减少,黏膜红肿消失、分泌物减少。结论地衣芽胞杆菌对实验性家兔金黄色葡萄球菌和大肠埃希菌阴道炎的治疗有效。地衣芽胞杆菌与乳杆菌的作用相似,具有维持阴道菌群平衡的作用。     

Changes in microbial populations during anaerobic flax retting

D onaghy , J.A., L evett , P.N. & H aylock , R.W. 1990. Changes in microbial populations during anaerobic flax retting. Journal of Applied Bacteriology 69 , 634–641.
The bacterial flora of industrial and laboratory scale anaerobic flax rets were determined at intervals throughout the rets. Although after an initial lag period total bacterial numbers remained roughly constant there were fluctuations in the bacterial species constituting the total. Pure culture rets and enzyme assays were used to determine which strains had retting potential. Of the strains demonstrated to have retting ability Bacillus licheniformis and B. subtilis were numerically dominant from 10 to 40 h and were succeeded in dominance by Clostridium acetobutylicum and Cl. felsineum .     

Regulation of the expression of lipoxygenase genes in <Emphasis Type="Italic">Prunus persica</Emphasis> fruit ripening

Three genes of the lipoxygenase (LOX) family in peach (Prunus persica var. compressa cv. Ruipan 4) were cloned, and their expression patterns during fruit ripening were analyzed using real-time quantitative PCR. All of the three peach LOX genes had been expressed during fruit ripening; however, their expression patterns were significantly different. During the normal ripening of peach fruits, the expression levels of PpLox1, PpLox2 and PpLox3 increased in varying degrees accompanying upsurge of ethylene evolution. After treated by methyl jasmonic acid (MeJA), the peak of ethylene releasing occurred in advance, and the declining rate of fruit hardness was accelerated, the expression level of the three peach LOX genes in fruits markedly enhanced at the early stage of storage, but significantly decreased at the late storage stage. So, it could be suggested that all three LOXs relate to fruit ripening; however, their functions might be different. PpLox1 expression increase along with the upsurge of ethylene evolution in both control and MeJA-treated peach fruits suggested that PpLox1 probably played a major role in the peach fruit ripening. Expression peak of PpLox2 appeared at the 1 DAH (days after harvest) in both control and MeJA-treated peach fruits, while obvious changes in ethylene evolution and fruit hardness was not observed, which suggested that the rise of PpLox2 expression can be induced by certain stimulation related to ripening, such as harvesting stress and MeJA treatment. The expression of PpLox3 kept a lower level in the natural ripening fruits, whereas raced up at the early stage of storage in the fruits treated with MeJA, which indicated that PpLox3 was expressed inductively and had minor roles during the normal ripening of peach fruits, but when encountered with external stimulation, its expression level would rapidly enhance and accelerate the ripening of peach fruit.     

Genetic relationship among Bacillus licheniformis rolling-circle-replicating plasmids and complete nucleotide sequence of pBL63.1, an atypical replicon

The degree of biodiversity among Bacillus licheniformis plasmids and their relation to other Bacillus subtilis group plasmids has been evaluated. To attain this goal we surveyed the diversity and linkage of replication modules in a collection of 21 naturally occurring plasmids of B. licheniformis strains, isolated from different geographical areas. On the basis of rep gene sequence analysis it was possible to group the B. licheniformis plasmids rep genes in two main cluster. Comparison with known rep genes from Bacillus rolling-circle-replicating (RCR) plasmids revealed the presence in B. licheniformis plasmids of replication genes with a DNA sequence peculiar to B. licheniformis species together with rep genes with a very high sequence similarity to B. subtilis plasmids. Furthermore, the molecular organization of an atypical replicon, pBL63.1, was shown. This plasmid did not display any significant similarity with known Bacillus RCR plasmids. The complete nucleotide sequence evidenced a replication module with an unexpected similarity with Rep proteins from RCR plasmids of bacterial species phylogenetically distantly related to Bacillus. pBL63.1 represents an exception to the low-level diversity hypothesis among Bacillus RC replicons.     

库尔勒香梨黑头病拮抗菌的筛选和鉴定

【背景】库尔勒香梨黑头病是近年来发现的一种由芸薹生链格孢菌(Alternaria brassicicola)XL2引起的采后病症,由于其高侵染率和高腐烂率造成了极大的经济损失,目前已成为库尔勒香梨采后储运的主要防治病症之一。【目的】发掘高效的库尔勒香梨黑头病拮抗菌,探索拮抗菌株的抑菌作用,为其生物防治提供潜在资源菌。【方法】从采后健康果蔬表面分离不同微生物,采用平板对峙法,以A.brassicicola XL2为靶标菌筛选具有拮抗作用的菌株,结合形态学观察、生理生化检测和16S rRNA基因序列分析鉴定拮抗菌株分类地位;检测拮抗菌无菌滤液对A. brassicicola XL2的抑制效应,显微观察拮抗菌对A.brassicicola XL2菌丝生长的影响;验证拮抗菌发酵液在库尔勒香梨果实上的抑菌活性。【结果】从新疆油桃表面分离获得90株菌,其中菌株Y2对A. brassicicola XL2有较强拮抗作用,经鉴定其为枯草芽孢杆菌(Bacillus subtilis)。菌株Y2的无菌滤液对A. brassicicola XL2菌落生长具有明显抑制作用,2%的无菌滤液抑菌率达到70.96%;Y2无菌滤液造成A.brassicicola XL2菌丝扭曲变形、分枝增加、尖端出现致密结构等异常现象;Y2发酵液和无菌滤液明显抑制A.brassicicola XL2的孢子萌发;Y2发酵液在库尔勒香梨果实上具有较高抑菌活性,对库尔勒香梨病斑直径抑制率达到37.66%,深度抑制率达到42.74%。【结论】枯草芽孢杆菌(B.subtilis)Y2能有效抑制A. brassicicola XL2的生长,对库尔勒香梨黑头病具有显著的生物防治效果。     

Biological control of grey mould in strawberry fruits by halophilic bacteria

Aims:  Grey mould caused by Botrytis cinerea is an economically important disease of strawberries in Tunisia and worldwide. The aim of this study was to select effective halophilic bacteria from hypersaline ecosystems and evaluate the abilities of antifungal bacteria to secrete extracellular hydrolytic enzymes, anti- Botrytis metabolites and volatiles.
Methods and Results:  Grey mould was reduced in strawberry fruits treated with halophilic antagonists and artificially inoculated with B. cinerea . Thirty strains (20·2%) were active against the pathogen and reduced the percentage of fruits infected after 3 days of storage at 20°C, from 50% to 91·66%. The antagonists were characterized by phenotypic tests and 16S rDNA sequencing. They were identified as belonging to one of the species: Virgibacillus marismortui , B. subtilis , B. pumilus , B. licheniformis , Terribacillus halophilus , Halomonas elongata , Planococcus rifietoensis , Staphylococcus equorum and Staphylococcus sp. The effective isolates were tested for antifungal secondary metabolites.
Conclusions:  Moderately halophilic bacteria may be useful in biological control against this pathogen during postharvest storage of strawberries.
Significance and Impact of the study:  The use of such bacteria may constitute an important alternative to synthetic fungicides. These moderate halophiles can be exploited in commercial production and application of the effective strains under storage and greenhouse conditions.     

Molecular characterisation of bacterial contamination in semi-final gelatine extracts, using denaturing gradient gel electrophoresis

Contamination of gelatine may affect the safety and/or quality of its applications. Characterisation of bacterial isolates from semi-final gelatine batches revealed thermotolerant, aerobic, endosporeforming contaminants. In this paper, bacterial contamination in gelatine batches is analysed without previous isolation, by means of denaturing gradient gel electrophoresis (DGGE) of PCR-amplified 16S rDNA sequences. V9 and V6-V8 regions of the 16S rDNA gene were found more suitable for this purpose than V1 or V3 regions. Bacillus fumarioli, Bacillus licheniformis, members of the 'Bacillus cereus group', Bacillus subtilis, Bacillus shackletonii, Brevibacillus borstelensis and Brevibacillus agri were detected.     

Isolation, characterization, and identification of bacterial contaminants in semifinal gelatin extracts

Bacterial contamination of gelatin is of great concern. Indeed, this animal colloid has many industrial applications, mainly in food and pharmaceutical products. In a previous study (E. De Clerck and P. De Vos, Syst. Appl. Microbiol. 25:611-618), contamination of a gelatin production process with a variety of gram-positive and gram-negative bacteria was demonstrated. In this study, bacterial contamination of semifinal gelatin extracts from several production plants was examined. Since these extracts are subjected to harsh conditions during production and a final ultrahigh-temperature treatment, the bacterial load at this stage is expected to be greatly reduced. In total, 1,129 isolates were obtained from a total of 73 gelatin batches originating from six different production plants. Each of these batches was suspected of having bacterial contamination based on quality control testing at the production plant from which it originated. For characterization and identification of the 1,129 bacterial isolates, repetitive-element PCR was used to obtain manageable groups. Representative strains were identified by means of 16S rRNA gene sequencing, species-specific gyrB PCR, and gyrA and rpoB sequencing and were tested for gelatinase activity. The majority of isolates belonged to members of Bacillus or related endospore-forming genera. Representative strains were identified as Bacillus cereus, Bacillus coagulans, Bacillus fumarioli, Bacillus amyloliquefaciens, Bacillus licheniformis, Bacillus pumilus, Bacillus sonorensis, Bacillus subtilis, Bacillus gelatini, Bacillus thermoamylovorans, Anoxybacillus contaminans, Anoxybacillus flavithermus, Brevibacillus agri, Brevibacillus borstelensis, and Geobacillus stearothermophilus. The majority of these species include strains exhibiting gelatinase activity. Moreover, some of these species have known pathogenic properties. These findings are of great concern with regard to the safety and quality of gelatin and its applications.     

Keratinolytic potential of Bacillus licheniformis RG1: structural and biochemical mechanism of feather degradation

Keratinolytic Bacillus licheniformis RG1 was used to study the mechanism of keratinolysis. Scanning electron microscopy studies revealed that bacterial cells grew closely adhered to the barbules of feathers, completely degrading them within 24 h. Biochemical studies indicated that the Bacillus strain produced an extracellular protease, which had keratinolytic potential. The extracellular keratinolytic activity (425 U) was synergistically enhanced by the addition of intracellular disulfide reductases (1712 U). However, these enzymes alone (keratinase and disulfide reductase), without live bacterial cells, failed to degrade the feather. Complete feather degradation was obtained only when living bacterial cells were present, emphasizing that bacterial adhesion plays a key role during the degradation process. The bacterial cells probably provide a continuous supply of reductant to break disulfide bridges. In addition, sulfite detected in the extracellular broth during feather degradation indicated that sulfitolysis may also play a role in feather degradation by the bacterium.