辛烯基琥珀酸菊粉酯的乳化及抑霉性能研究

以菊粉为参照,研究了取代度、添加量、冻融等因素对辛烯基琥珀酸菊粉酯乳化能力的影响,考察了辛烯基琥珀酸菊粉酯对扩展青霉、黑曲霉和黑根霉菌丝生长、孢子萌发和芽管伸长的抑制作用。试验结果表明:菊粉经辛烯基琥珀酸酐改性后具有良好的乳化性,其乳化能力随取代度(DS)和添加量的增加而增大。当辛烯基琥珀酸菊粉酯(DS=3.17×10-2)浓度为2.50%时,乳化液乳化效果和冻融稳定性良好,乳液颗粒大小一致、不聚集。抑菌实验表明辛烯基琥珀酸菊粉酯对扩展青霉、黑曲霉和黑根霉三种霉菌的最小抑菌浓度(MIC)分别为1.00%、4.00%和2.00%(m/V),其对扩展青霉、黑曲霉和黑根霉菌丝生长、孢子萌发和芽管伸长抑制作用随辛烯基琥珀酸菊粉酯浓度增加而增强。低于MIC浓度时,辛烯基琥珀酸菊粉酯对扩展青霉菌丝生长、孢子萌发和芽管伸长的抑制作用最强,其次是黑曲霉,对黑根霉的抑制作用较弱。     

肉桂醛对番茄采后灰霉病的抑制作用及其对品质的影响

为研究肉桂醛对番茄采后灰霉病的抑制作用及其对番茄果实品质的影响,在离体条件下分别研究肉桂醛对
灰葡萄孢菌菌丝生长、孢子萌发的抑制作用,采用人工活体接种法研究肉桂醛对番茄果实灰霉病斑的控制作用,及
其对番茄自然发病果实的品质的影响。结果表明,肉桂醛对灰葡萄孢菌的菌丝生长和孢子萌发均有较好的抑制作
用,对菌丝生长的EC50值为95.6 μg/mL,质量浓度为60 μg/mL时对孢子萌发抑制率为100%;活体条件下肉桂醛能够
有效地抑制番茄果实采后灰霉病病斑的扩展,以4 000 μg/mL效果最好,且在此质量浓度条件下,对于降低果实质
量损失率,维持番茄硬度、可溶性固形物、可滴定酸和VC含量均具有较好的效果。4 000 μg/mL肉桂醛处理能够有
效地控制番茄采后灰霉病的发生及延长其保鲜期。     

枯草芽孢杆菌C3产抗菌物质发酵培养基的优化

该文利用对黑曲霉孢子萌发有抑制作用的枯草芽孢杆菌C3,研究优化产抗菌物质的发酵培养基组分.在碳源、氮源、C/N单因素多水平试验结果的基础上,设计Na+、Mg2+、K+度3因素3水平L9(33)正交试验,研究无机盐离子对枯草芽孢杆菌产抗菌物质的影响.结果表明,碳源为1％葡萄糖,氮源为蛋白胨和酵母浸粉各1.5％,碳氮比为1∶3,NaCl为0.5％,KH2PO4为0.1％,MgSO4·7H2O为0.15％时,枯草芽孢杆菌产抗菌物质的抑菌效果明显,对霉菌孢子萌发的抑制率提高了118.64％.     

壳聚糖金属配合物对黑曲霉的抑制活性研究

通过观察黑曲霉菌丝体的生长及孢子萌发情况,考察壳聚糖(CS)及壳聚糖锌(CS-Zn)、壳聚糖镍(CS-Ni)的抗真菌性能。结果表明：壳聚糖、壳聚糖锌和壳聚糖镍对黑曲霉孢子萌发和菌丝体生长均具有明显抑制作用,且壳聚糖金属配合物的抑菌效果比壳聚糖本身更强,其中壳聚糖镍最强。壳聚糖镍对黑曲霉的抑菌活性受壳聚糖分子质量、环境pH 值、质量浓度因素的影响较大。分子质量为5kD 的CS 制备的CS-Ni 抗真菌效果最好;CS-Ni 抑菌效果在pH3～7.5 时随pH 值降低而增强;随CS-Ni 质量浓度(0～0.75mg/mL)的增加而增强。     

枯草芽孢杆菌C3产抗菌物质发酵条件优化

利用筛选的枯草芽孢杆菌(Bacillus subtilis)C3研究提高产抗菌物质的发酵条件。通过测定枯草芽孢杆菌C3抗菌物质对黑曲霉孢子萌发的抑制率,设计6因素3水平正交试验得到优化的发酵条件为:种子液的菌龄12h,种子液接种量2%,发酵培养基装液量75mL/250mL,发酵培养基初始pH 7.0,发酵温度37℃,发酵时间48h。在优化发酵条件下,枯草芽孢杆菌C3产抗菌物质的抑菌活性比优化前提高了26.52%。     

烟草叶围细菌的分离及其对Alternaria alternata的拮抗作用

分离到烟草叶围细菌136株,通过对峙培养实验筛选出对烟草赤星病菌A.alternata有较强拮抗活性的9个菌株.离体叶片生防测定实验表明,9株细菌均能不同程度地减轻烟草赤星病的发生.其中菌株Tpb88具有较强和稳定的拮抗作用,无菌滤液实验表明,叶围细菌Tpb88在一定浓度范围内能有效抑制A.alternata菌丝生长、孢子萌发和芽管伸长,且浓度越高,抑制能力越强,结果表明Tpb88对烟草赤星病菌的拮抗机制可能为抗菌物质的产生.     

复配精油对粮油中霉菌防治的增效作用及机理研究

开发新型天然防霉剂控制粮食霉变是保障粮食质量安全的重要途径之一。为研究复配植物精油对粮油储藏过程中常见霉菌赭曲霉(Aspergillus ochrator)、黄曲霉(Aspergillus flavus)和黑曲霉(Aspergillus niger)的防霉效果,挑选活性较强的植物精油进行复配并对联合防霉效果进行评价。通过复配植物精油对霉菌孢子萌发、菌丝干重和细胞完整性的影响,对其防霉机理进行初步探究。结果显示,牛至精油对赭曲霉和黑曲霉的防霉效果最好,抑菌圈直径分别为（27.83±0.58 ）、（15.33±0.29）mm,肉桂醛对黄曲霉的防霉效果最好,抑菌圈直径为（18.50±0.87 ）mm;山苍子精油与牛至精油、肉桂醛与牛至精油复配体积比为2：8时对3种霉菌的防霉效果较优;通过对部分抑菌浓度指数判读,两组植物精油复配对黑曲霉和赭曲霉的防治效果为协同作用,对黄曲霉的防治效果为相加作用;山苍子精油与牛至精油按体积比2：8复配可抑制霉菌孢子萌发和菌丝生长、破坏细胞的完整性、改变孢子和菌丝结构;山苍子精油和牛至精油按体积比2：8复配施用于含黄曲霉的玉米上,可有效降低玉米中黄曲霉毒素B1和赭曲霉毒素的含量。本研究为山苍子精油与牛至精油复配作为防霉剂提供理论支持。     

低温等离子体及防腐剂对解淀粉芽孢杆菌芽孢灭活效果的影响

为了研究低温等离子体及防腐剂对解淀粉芽孢杆菌（Bacillus amyloliquefaciens）芽孢杀死率的影响,分别采用不同质量浓度的单一和复合防腐剂加入到含有菌悬液的培养基中,采用不同功率与时间低温等离子体对菌体进行处理,考察不同质量浓度防腐剂及不同功率与时间低温等离子体对解淀粉芽孢杆菌芽孢致死率的影响。结果表明,单一防腐剂抑制效果由大到小顺序为脱氢乙酸钠＞乳酸链球菌素＞山梨酸钾,脱氢乙酸钠在质量浓度为4 mg/mL时,芽孢抑制率可达97%;脱氢乙酸钠∶乳酸链球菌素（1∶1）、脱氢乙酸钠∶山梨酸钾∶乳酸链球菌素（1∶2∶1）复合防腐剂抑制效果较好,质量浓度为0.5 mg/mL时芽孢抑制率可达90%以上;低温等离子体在相同功率下,时间越短,抑菌效果越好,最佳抑菌效果条件为300 W、50 s。     

Chemical composition and antifungal activity of essential oil from Cicuta virosa L. var. latisecta Celak

The essential oil extracted from the fruits of Cicuta virosa L. var. latisecta Celak was tested in vitro and in vivo against four foodborne fungi, Aspergillus flavus, Aspergillus oryzae, Aspergillus niger, and Alternaria alternata. Forty-five different components accounting for 98.4% of the total oil composition were identified by gas chromatography-mass spectrometry. The major components were γ-terpinene (40.92%), p-cymene (27.93%), and cumin aldehyde (21.20%). Antifungal activity was tested by the poisoned food technique against the four fungi. Minimum inhibitory concentration against the fungi was 5 μL/mL and percentage inhibition of mycelial growth was determined at day 9. The essential oil had a strong inhibitory effect on spore production and germination in all tested fungi proportional to concentration. The oil exhibited noticeable inhibition on dry mycelium weight and synthesis of aflatoxin B? (AFB?) by A. flavus, completely inhibiting AFB(1) production at 4 μL/mL. The effect of the essential oil on inhibition of decay development in cherry tomatoes was tested in vivo by exposing inoculated and control fruit to essential oil vapor at a concentration of 200 μL/mL. Results indicated that the essential oil from C. virosa var. latisecta (CVEO) has potential as a preservative to control food spoilage.     

激活剂对米曲霉孢子萌发率的影响

双菌种制曲可以弥补米曲霉分泌酶系的不足,但米曲霉和黑曲霉孢子萌发时间不一致的问题限制了双菌种制曲的实际应用。研究首先明确了在相同培养条件下黑曲霉和米曲霉孢子萌发的时间差,添加激活剂可以加快米曲霉的孢子萌发速度,激活剂的最佳浓度为0.4%。添加该浓度激活剂,在不同温度下培养米曲霉和黑曲霉的孢子,结果表明,38℃下培养4.5 h,能使米曲霉和黑曲霉的孢子萌发率基本达到一致,分别达到72%和73%。     

碳酸铵对柑橘酸腐病菌的抑制效果及作用机制

由酸腐病菌引起的酸腐病是柑橘重要的采后病害,目前缺少有效控制酸腐病的杀菌剂。本研究分析了碳酸铵作为通常认为安全的药剂对酸腐病菌的抑菌活性和可能的作用机制。结果显示：碳酸铵可以抑制孢子萌发和芽管伸长,抑制菌丝生长,并且抑制效应与质量浓度呈正相关,在0.8 g/L条件下完全抑制孢子萌发和菌丝生长。进一步分析表明,碳酸铵抑制孢子活性,高效抑制菌丝呼吸,并改变膜通透性,增加离子渗出率,加剧核酸和蛋白的丢失,进而导致菌丝细胞功能丧失。活体实验结果表明,夏橙接种孢子浓度为1×106 个/mL 的20 μL酸腐病菌孢子悬浮液,经20 g/L碳酸铵处理可显著降低其病斑直径,减轻果实发病。结论：碳酸铵可作为杀菌剂的替代方法控制柑橘果实的酸腐。     

Breaking of structural dormancy in seeds of Tetrapleura tetraptera by Aspergillus niger

Aspergillus niger (strain UUF9202) significantly reduced the dormancy period and boosted aggregate germination percentage (AGP) in seeds of Tetrapleura tetraptera. A net reduction in mean germination time (MGT) to 12 days and an increase from 0 to 42% AGP were obtained in 32 days. The optimal spore inoculum of the fungus was 8.5 × 10≥10 ml^?1 per 100 seeds in 96 h pregermination incubation. The potential of some physical factors in combination with this fungal concentration in enhancing AGP was evaluated. The treatments were as follows: (i) hot water scarification at 30°C, 50°C, 80°C and 100°C plus A niger; and (ii) nicking by decoating at either the micropylar or chalazal ends plus A niger. Micropylar scarification plus A niger gave the highest AGP (94%) followed by chalazal scarification plus A niger (86%) and hot water dip at 80°C + A niger (82%). The control seeds which were soaked in presterilised (by autoclaving at 121°C for 15 min) A niger spore suspension at 30°C gave zero germination.     

Inhibition of Spore Germination of Phakopsora Pachyrhizi Using Crude Extracts of Amaranthus Spinosus

The effectiveness of methanolic and n-hexane crude extracts of Amaranthus spinosus to inhibit the spore germination of Phakopsora pachyrhizi, a causal agent of soybean rust disease was studied. Both methanolic and n-hexane crude extracts inhibited spore germination at concentrations of 0.1% to 5.0%. Methanolic extract of the roots at a concentration of 2.5% inhibited 55% of spore germination, and this result was similar when higher concentration at 5% of methanolic and n-hexane extracts of the flowers was used. The presence of alkaloids, flavonoids, tannins, saponins, and terpenoids in the extract may be responsible for the inhibition. The extract was potential to be utilized as a botanical fungicide.     

In vitro inhibition of postharvest pathogens of fruit and control of gray mold of strawberry and green mold of citrus by aureobasidin A

Aureobasidin A (AbA), an antifungal cyclic depsipeptide antibiotic produced by Aureobasidium pullulans R106, has previously been shown to be effective against a wide range of fungi and protozoa. Here we report the inhibitory effects of AbA on spore germination, germ tuber elongation and hyphal growth of five pathogenic fungi including Penicillium digitatum, P. italicum, P. expansum, Botrytis cinerea and Monilinia fructicola, which are major pathogens causing postharvest diseases of a variety of fruits. AbA inhibited five pathogenic fungi by reducing conidial germination rates, delaying conidial germination initiation, restricting elongation of germ tuber and mycelium, as well as inducing abnormal alternations of morphology of germ tubes and hyphae of these fungi. The sensitivity of these fungi to AbA was pathogen species-dependent. P. digitatum was the most sensitive and M. fructicola the least. Importantly, AbA at 50 microg/ml was effective in controlling the citrus green mold and in reducing the strawberry gray mold incidence and severity, caused by P. digitatum and B. cinerea, respectively, after artificial inoculation. AbA and/or its analogs, therefore, hold promise as relatively safe and promising fungicide candidates to control postharvest decays of fruits, because AbA targets the inositol phosphorylceramide (IPC) synthase, an enzyme essential for fungi but absent from mammals.     

药食两用植物提取液对李果实采后常见致腐真菌抑制作用

采用滤纸片法比较七种植物提取液对李果实采后常见致腐真菌的抑菌效果,研究甘草和肉桂复合提取液对褐腐病菌（Monilinia fructicola）的抑制效果及抑菌机理。结果表明,1.0g/mL甘草提取液对褐腐病菌抑制作用最强,抑菌圈直径为12.03mm;1.0 g/mL肉桂提取液对酵母菌（Saccharomyces）、黑曲霉（Aspergillus niger）、米曲霉（Aspergillus oryzae）抑制作用最强,抑菌圈直径分 别为21.25 mm、17.49 mm和13.28 mm。 甘草、肉桂提取液对褐腐病菌的最小抑菌浓度（MIC）值分别为7.81 mg/mL、15.63 mg/mL,两者 联合使用时对褐腐病菌的分级抑菌浓度（FIC）值为0.75,抑菌效果增强。 甘草、肉桂提取液处理后的褐腐病菌培养液相对电导率分别 达到96.64%、48.47%;可溶性蛋白质含量分别达到50.6 μg/mL、25.1 μg/mL。 推测其破坏了褐腐病菌细胞膜结构,改变了细胞膜渗透性,导致细胞质外泄,从而发挥抑菌作用。     

Inactivation of Mucor plumbeus by the combined actions of chitinase and high hydrostatic pressure

Sporangiospores were treated with high hydrostatic pressure and/or fungal chitinase in order to study the inhibition of germination and growth of the food spoiling mold Mucor plumbeus. Total fungal inhibition was obtained either at 4.0 kbar or by 10 U/ml of chitinase from Penicillium janthinellum. A pretreatment with 1 U/ml of the same chitinase reduced the pressure necessary to obtain complete spore inhibition to 3 kbar.     

Inactivation of Penicillum expansum in sour cherry juice, peach and apricot nectars by pulsed electric fields

Inhibitory effects of pulsed electric fields (PEF) on Penicillum expansum inoculated into sour cherry juice, apricot and peach nectars were determined based on germination tube elongation, spore germination rate, and light and scanning electron microscopy (SEM) observations in this study. After inoculation of juice/nectar samples with P. expansum spores at the level of 10(5)-10(6)cfu/mL, the samples were processed by bench scale PEF pulse generator as a function of differing electric field strengths (0, 13, 17, 20, 23, 27, 30 and 34kV/cm) and processing times (0, 62, 94, 123, 163, 198 and 218mus). Results revealed that with an increase in electric field strength and processing time, germination tube elongation and spore germination rate were completely inhibited. Light and SEM observations revealed considerable morphological alterations in fungal conidia such as cytoplasmic coagulation, vacuolations, shrinkage and protoplast leakage. PEF processing of juice/nectars was demonstrated to be effective in inactivating P. expansum. To our knowledge, this is the first study confirming the inhibitory effects of PEF on germination tube elongation and spore germination rate of P. expansum in fruit juice/nectars.     

柠檬皮中柠檬苦素对根霉的抑菌活性和机理

通过测定柠檬皮中柠檬苦素对根霉的最小抑菌浓度(MIC)、最小杀菌浓度(MBC)、孢子萌发抑制率、菌丝萌发抑制率确定其抑菌活性,根据测定各因素对抑菌活性的影响确定抑菌活性的稳定性;并通过扫描电镜观察和测定根霉细胞外碱性磷酸酶(AKP)含量和蛋白质含量,菌丝体的总糖含量,分析柠檬皮中柠檬苦素对根霉的抑菌机理。结果表明:柠檬皮中柠檬苦素对根霉的最低抑菌浓度(MIC)和最小杀菌浓度(MBC)分别为1250、5000 μg/mL;对根霉孢子萌发的抑制效果更强,对孢子萌发和菌丝生长抑制的EC₅₀值分别为918.34和1707.31 μg/mL。柠檬苦素对根霉的抑菌活性不受温度和明胶的影响;pH为4时,抑菌活性最强;Fe3+、Fe2+均能显著(p<0.05)提高柠檬苦素的抑菌活性。柠檬苦素能使根霉的糖、蛋白质、AKP等胞内物质渗出;扫描电镜观察也发现经柠檬苦素处理的根霉孢子凹陷和皱缩严重,且溶出物明显;菌丝出现断裂扭曲、变形、变细。因此,柠檬苦素能破坏根霉的细胞壁和细胞膜的完整性,使胞内物质渗出,菌丝体和孢子变形,从而使根霉生长代谢受到影响。     

Mature seeds of Sorghum contain proteins toxic to aflatoxin-producing Aspergillus flavus

Crude acid extract of mature Sorghum seeds showed partial inhibition of spore germination and growth of aflatoxin-producing Aspergillus flavus strains. To find the protein components involved in this mechanism of inhibition, the crude extract was fractionated by differential precipitation followed by ion exchange chromatography in carboxymethyl cellulose. Five proteins of low molecular weight were isolated. The ability of each of the five proteins to inhibit the spore germination and hyphal extension of aflatoxin-producing Aspergillus flavus strains was tested. Protein 5 did not show any inhibition. Proteins 1, 2 and 4 showed complete inhibition of spore germination (1500–2000 spores/100 μl of medium) at a concentration of 15 μg/100 μl. Protein 3 showed partial inhibition only.     

Effect of Nisin on the Outgrowth of Clostridium botulinum Spores

Nisin, an antibiotic produced by certain strains of Streptococcus lactis, is effective in preventing the outgrowth of Clostridium botulinum spores. Type A C. botulinum spores were the most resistant to the inhibitory action of nisin requiring 1000-2000 I.U. of nisin/ml for a 50% inhibition of outgrowth on TPYG agar plates. Type E spores were more sensitive requiring only 50-100 I.U./ml for 50% inhibition of outgrowth on TPYG agar plates. Type B spores displayed an intermediate level of sensitivity requiring 500-1000 I.U. of nisin/ml for 50% inhibition of outgrowth on TPYG agar plates. Similar levels of nisin were necessary to prevent spore outgrowth in TPYG broth and BHI broth over a 7-day incubation period. With prolonged incubation periods of up to 65 days in TPYG broth, spore outgrowth was observed sporadically at higher nisin levels with the type A and B spores which may indicate some decomposition of nisin with storage. Nisin levels of 5000 I.U./ml for the type A spores and 2000 I.U./ml for the type B spores and the Minnesota E spores were insufficient to prevent spore outgrowth by C. botulinurn in cooked meat medium. For the Beluga E spores, a nisin level of 2000 I.U./ml was necessary to prevent spore outgrowth in cooked meat medium. The need for higher levels of nisin in cooked medium to prevent spore outgrowth may be due to the binding of the nisin by meat particles.