白肋烟烟碱、总氮含量及氮碱比的配合力与遗传力分析

利用6个白肋烟品种以及采用Griffing双列杂交第2种方法组配的15个杂交组合对构成白肋烟品质的烟碱、总氮含量及氮碱比3个数量性状的配合力和遗传力进行了分析,结果表明:对于这3个品质性状的一般配合力(GCA),6个白肋烟亲本间均存在极显著差异,组合间除上部叶氮碱比的特殊配合力(SCA)差异不显著外,其余性状的SCA均存在极显著差异,所有性状的GCA方差均大于SCA方差;KY8959和B67在品质性状上GCA效应表现较优,TN86和B37分别在降低中部叶烟碱和提高总氮含量上具有较好的GCA效应。综合3个品质性状的SCA效应分析,组合(LAB21×鄂白001)和(B37×鄂白001)表现最优。中部叶和上部叶烟碱含量的广义遗传力均大于50%,表明其表型变异主要以可遗传变异为主,总氮含量和氮碱比的广义遗传力相对较低,表明了环境效应以及环境与品种的互作效应对性状的影响较大;烟碱含量以及上部叶氮碱比性状的狭义遗传力占广义遗传力的比例较高(59.2%～70%),而中部叶的总氮含量和氮碱比性状的狭义遗传力占广义遗传力的比例较小(50%以下),表明烟碱含量主要受可遗传的加性方差控制,而总氮含量的遗传受非遗传因素影响较大。     

烤烟主要农艺性状的遗传分析

为了快速准确地预测烤烟F₁的杂种优势,促进强优势杂交组合的选育,采用NCⅡ交配设计的方法,以7个烤烟品种(系)组配了12个杂交组合,探讨了亲本和F₁一些主要农艺性状的杂种优势表现,并对其配合力和遗传力进行了分析。结果表明,杂种优势因性状和杂交组合的不同表现出较大的差异,5个性状群体中亲优势大小顺序为株高>叶面积>叶长>叶宽>叶数,群体超亲优势除株高外均呈一定的负向;配合力的研究选出了本研究中较理想的杂交组合及亲本,遗传力的研究表明了各个性状选择较为可靠,但叶宽、叶面积性状受非加性遗传的作用较为突出,宜在较高的世代进行选择。综合各个性状的杂种优势和配合力来看,韭菜坪2号×G28,南江三号×Florda301是较好的组合;Florda301,韭菜坪2号是较好的亲本。     

烤烟化学成分的遗传效应分析

为科学合理地进行烤烟育种中的亲本筛选与组合配制,选育出化学成分协调的烤烟新品种(系),利用6个烤烟品种(K326、6388、RG17、K8、净叶黄和南江3号)按Griffing方法(Ⅱ)完全双列杂交配制出30个杂交组合,并对烟叶的烟碱、总氮、总糖、钾、氯、氮碱比、糖碱比和钾氯比等8个化学成分指标进行了初步遗传效应分析。结果表明,组合间的所有性状差异均达到了极显著水平,亲本间的一般配合力(GCA)和组合间的特殊配合力(SCA)均存在极显著差异,而且除氮碱比指标外的其他化学成分指标GCA方差均大于SCA方差,表明对本试验中烤烟绝大部分化学成分指标性状而言,亲本选择比组合配制更重要。对于GCA效应,RG17和南江3号品种分别具有提高钾和钾氯比的潜力,而6388则具有降低氯含量的潜力。基于烤烟化学品质目标分析SCA效应,30个组合中以K326×南江3号、净叶黄×南江3号和K8×净叶黄3个组合表现最佳,其次是K326×净叶黄和K8×RG17两个组合。化学成分指标性状间的遗传力存在较大差异,狭义遗传力以钾最大(33.82%),总糖最小(1.37%),而广义遗传力以氯和钾最大,分别为51.84%和50.04%,总糖最小(15.08%),只有钾的狭义遗传力占广义遗传力的比例超过了50%,说明钾的遗传以加性效应为主,这有利于培育高钾品种,且适宜进行早代选择,对于其他化学成分指标性状,在性状基本稳定的时期进行株系选择比较适宜。     

原生质体融合法提高棒状链霉菌的克拉维酸产量

采用原生质体融合技术,将克拉维酸生产菌——棒状链霉菌甘油耐受性突变株B71-14和舒巴坦钠耐受性突变株B71-50进行了原生质体融合。以2种抗性为选择标记,筛选融合子。从形态上与2亲本菌株不同的98株融合子中发现了1株融合子F-11,既有甘油抗性又有舒巴坦钠的抗性,其克拉维酸产量为742.71 mg/L,是亲本菌株B71-14(538.20 mg/L)的1.38倍,是亲本菌株B71-50(479.91 mg/L)的1.55倍。     

葡萄果色基因型的推断

为了使葡萄育种工作(主要指常规育种)更加卓有成效,必须重视亲本的选择选配。而为了有目的地选配亲本,就必须对亲本性状的遗传规律进行深入的研究,对亲本品种基因型的鉴定就是研究的主要内容之一。因为只有掌握了亲本品种的基因型,才能做到有的放失的选配亲本和预测杂种后代性状的表现。本文主要探讨葡萄果色的遗传规律,并推断葡萄果色的基因型。当然,这对于研究葡萄品种的系谱关系及起源也具有一定意义。     

甜菜数量性状配合力的测定和基因行为的分析

作物杂种优势的研究和利用是现代育种学中的一个重要领域。要获得杂种优势必须合理地选配亲本。亲本不仅需要良好的综合性状,还应具有较高的配合力,这是育种成功与否的关键。糖甜菜的很多主要经济性状,象根产量、含糖量、纯度以及影响糖产量的有害氮、可溶性灰分、甜菜碱、还原糖、果胶质等物质含量,均属于数量遗传的性状,受多基因控制。因此     

烤烟数量性状配合力和遗传力的研究

杂交育种工作极为重要的关键环节,一是正确选配亲本和尽早的识别组合的优劣,这就涉及性状配合力;二是如何正确地在分离世代中进行有效的选择,这就涉及性状的遗传力.本试验的目的是:(1)通过对配合力和遗传力的分析,探讨常用的几个烤烟亲本和F_1一些重要经济性状的配合力效应以及     

斑茅及其杂种后代主要经济性状研究

对斑茅、斑茅蔗杂种1代(F1)、回交1代(BC1)和回交2代(BC2)的主要经济性状的分析结果表明,在杂交和回交过程中,锤度表现为近中亲遗传,改良速度较快。斑茅的小茎性状有较高的遗传力,但茎径改良速度仍属较快。从已有结果预测,改良斑茅蔗高纤维、茎皮硬、空心蒲心、难剥叶和气根多等缺点难度较大。通过合理的后代选择和回交亲本选择策略,可望加速这些性状改良的进程。     

津巴布韦引进烤烟品种T29的栽培特性研究

通过大田试验,分析了施氮量、留叶数、打顶时间和留叶方式对津巴布韦引进烤烟品种T29主要经济性状的影响.结果表明:T29各主要经济性状指标不存在留叶数与氮肥互作效应;T29的产量、产值对氮处理和留叶数处理反应不敏感,施氮量对其上等烟比例、中等烟比例、级指、百叶重的影响也不显著,但留叶数超过21片/株以后,显著降低了上等烟比例和百叶重.足叶打顶产量最高,产值、上等烟比例、级指则以现蕾打顶最高.L2留叶方式综合经济性状最好.在中等土壤肥力条件下,建议T29的栽培措施为:施纯氮量60.0 ～ 90.0 kg/hm2,留叶数21片/株左右,现蕾期打顶,采用12的留叶方式.     

烤烟产质性状的双列杂交分析

利用6个烤烟品种(系)按双列杂交设计配制出15个杂交组合,并对有关产质性状进行了配合力分析.方差分析结果表明对多数产质性状,亲本间一般配合力、杂交组合间特殊配合力差异达显著或极显著水平,说明烤烟品种的这些性状受加性和非加性效应基因共同控制;但有些性状加性效应占主导地位,有些性状除加性效应外,非加性效应也起重要作用.根据亲本间一般配合力效应(GCA)分析及组合间特殊配合力效应(SCA)分析结果表明,同一亲本不同性状的GCA有较大差异,组合SCA与亲本GCA并无直接联系.     

藜麦蛋白对低钠盐体系中猪肉肌原纤维蛋白凝胶特性的影响

分别将3%、6%、9%和12%藜麦蛋白添加到低钠盐（0.40 mol/L NaCl、0.10 mol/L KCl和0.05 mol/L CaCl2）猪肉肌原纤维蛋白（myofibrillar protein,MP）体系中,考察藜麦蛋白添加量对复合蛋白溶液/凝胶的理化性质、蛋白二级结构、化学作用力和微观结构的影响。结果表明：藜麦蛋白的添加提高了MP的凝胶强度、保水性和动态流变特性,这是因为藜麦蛋白提高了复合蛋白溶液的蛋白溶解度和ζ-电位绝对值,降低了蛋白粒径;复合蛋白体系中的化学作用力以二硫键和疏水作用为主,但是藜麦蛋白的添加提高了离子键和氢键含量;藜麦蛋白促进了无规则卷曲向β-折叠和α-螺旋转化,增加了凝胶的稳定性;扫描电镜显示,藜麦蛋白提高了复合凝胶的致密程度。综上,藜麦蛋白作为一种优质植物蛋白,可以增强MP的凝胶特性,特别是当藜麦蛋白添加量为6%～9%时,对低钠盐体系中MP凝胶特性的改善效果较好。     

NMR-based metabolic profiling and in vitro antioxidant and hepatotoxic assessment of partially purified fractions from Golden germander (Teucrium polium L.) methanolic extract

Golden germander (Teucrium polium L.) is a Mediterranean shrub of the Labiatae family, used in traditional medicine for its diuretic, antipyretic, diaphoretic, antispasmodic, tonic, anti-inflammatory, antihypertensive, anorexic, analgesic, antibacterial and antidiabetic effects. Like other plants of the Teucrium genus, it was widely popular because of its hypoglycemic and hypolipidemic properties but various cases of T. polium-induced hepatitis have been reported. neo-Clerodane diterpenoids, considered chemotaxonomic markers for the Teucrium genus, are believed to be responsible for the observed hepatotoxicity. The plant also produces flavonoids and phenylethanoid glycosides to which the antioxidant and cytoprotective therapeutic properties of its preparations can be traced back. In order to establish a herbal formula that preserves the plant beneficial properties, T. polium leaf drug has been subjected to a bio-guided fractionation. The different phytocomplexes obtained were analyzed by means of an extensive antioxidant screening and hepatotoxicity evaluation against HepG2, a human hepatoblastoma cell line. The cytotoxicity of the fractions was also evaluated against HeLa and A549 cell lines. In order to identify the substances responsible for the bioactivities, NMR-based metabolic profiling techniques of all the phytocomplexes were performed. Data obtained highlighted the possibility of preparing strong antioxidant extracts, useful as food additives, such as MeOH-2, and MeOH-3, completely devoid of hepatotoxic components.     

Addition of pasture plant essential oil in milk: influence on chemical and sensory properties of milk and cheese

The aim of this experiment was to study the effect of the addition, to milk, of an essential oil (EO) obtained from the hydrodistillation of plants collected from a mountain natural pasture on the milk and cheese sensory properties. The EO was mainly composed of terpenoid compounds (67 of the 95 compounds identified) as well as ketones, aldehydes, alcohols, esters, alkanes, and benzenic compounds. In milk, the addition of this EO at the concentration of 0.1 μL/L did not influence its sensory properties, whereas at 1.0 μL/L, sensory properties were modified. In cheeses, the effect of adding EO into milk was studied in an experimental dairy plant allowing the production of small Cantal-type cheeses (10 kg) in 3 vats processed in parallel. The control (C) vat contained 110 L of raw milk; in the other 2 vats, 0.1 μL/L (EO1) or 3.0 μL/L (EO30) of EO were added to 110 L of the same milk. Six replicates were performed. After 5 mo of ripening, chemical and sensory analyses were carried out on the cheeses, including determination of the volatile compounds by dynamic headspace combined with gas chromatography-mass spectrometry. The EO did not influence the sensory properties of the cheeses at the lower concentration (EO1). However, the EO30 cheeses had a more intense odor and aroma, both characterized as “mint/chlorophyll” and “thyme/oregano.” These unusual odors and aromas originated directly from the EO added. In total, 152 compounds desorbing from cheese were found, of which 41 had been added with the EO; in contrast, 54 compounds of the EO were not recovered in the cheese. Few volatile compounds desorbing from cheeses, other than the added compounds, were affected by EO addition. Among them, 2-butanol, propanol, and 3-heptanone suggested a slight effect of the EO on lipid catabolism. The antimicrobial activity of terpenes is not or is only marginally involved in the explanation of the influence of the botanical composition of the meadows on the pressed cheeses sensory properties.     

Use of PFGE typing for tracing contamination with Listeria monocytogenes in three cold-smoked salmon processing plants

The sites of Listeria monocytogenes contamination in three cold-smoked salmon (Salmo salar) processing plants were detected by sampling salmon and the plant's environment and equipment at different production stages. Of the 141 samples collected from three processing plants, 59 (42%) were contaminated with L. monocytogenes. The rates of contamination varied as to the plant and the sample source. L. monocytogenes isolates from 17 various contaminated seafood products (fresh, frozen and smoked fishes, cooked mussels) were also studied. A total of 155 isolates from the three plants and the various seafoods were characterized by genomic macrorestriction using ApaI and SmaI with pulsed-field gel electrophoresis (PFGE) and 82 isolates were serotyped. Macrorestriction yielded 20 pulsotypes and serotyping yielded four serovars: 1/2a, 1/2b, 1/2c, 4b (or e), with 77 (93%) belonging to serovar 1/2a. One clone of L. monocvtogenes predominated and persisted in plant I and was the only pulsotype detected in the final product although it was not isolated from raw salmon. No L. monocytogenes was detected in the smoked skinned salmon processed in plant II, even though 87% of the raw salmon was contaminated. All the smoked salmon samples collected in plant III were contaminated with a unique clone of L. monocytogenes, which may have occurred during slicing. In the three plants, the contamination of final products did not seem to originate from the L. monocytogenes present on raw salmon, but from the processing environment.     

Contamination patterns of Listeria monocytogenes in cold-smoked pork processing

Contamination patterns of Listeria monocytogenes were studied in a cold-smoked pork processing plant to identify the sources and possible reasons for the contamination. Environmental sampling combined with pulsed-field gel electrophoresis (PFGE) subtyping and serotyping were applied to investigate the genetic diversity of L. monocytogenes in the plant environment and ready-to-eat (RTE) cold-smoked pork products. A total of 183 samples were collected for contamination analyses, including samples of the product at different stages during manufacture (n = 136) and environmental samples (n = 47) in 2009. L. monocytogenes isolates, previously recovered from 73 RTE cold-smoked pork samples and collected from the same meat processing plant in 2004, were included in this study. The brining machine and personnel working with brining procedures were the most contaminated places with L. monocytogenes. The overall prevalence of L. monocytogenes in raw pork (18%) increased to 60% after the brining injections. The brining machine harbored six different PFGE types belonging to serotypes 1/2a, 1/2c, 4b, and 4d, which were found on the feeding teeth, smooth surfaces, and spaces of the machine, thus potentially facilitating dissemination of L. monocytogenes contamination. Two PFGE types (2 and 8) belonging to serotypes 1/2a and 1/2c were recovered from RTE cold-smoked pork collected in 2004, and from surfaces of the brining machine sampled in 2009, and may indicate the presence of persistent L. monocytogenes strains in the plant. Due to poor hygiene design, removal of the brining machine from the production of cold-smoked meat products should be considered to reduce L. monocytogenes contamination in the finished products.     

L-抗坏血酸传感器在果汁中Vc含量的测定

本文利用花椰菜组织通过交联制备L-抗坏血酸传感器,该传感器在pH6.0、0.1mol/L的KH_2PO_4-Na_2HPO_4真缓冲溶液中对Vc标准溶液的线性范围为5.0×10~(-5)×1.8×10~(-3)mol/L,响应时间1min。电极使用寿命在1个月以上。利用该传感器测定了部分水果和果汁中Vc的含量,所得结果与分光光度法(2,4-二硝基苯肼法)测得结果一致。     

Antimicrobial effects of Finnish plant extracts containing flavonoids and other phenolic compounds

Plant phenolics, especially dietary flavonoids, are currently of growing interest owing to their supposed functional properties in promoting human health. Antimicrobial screening of 13 phenolic substances and 29 extracts prepared from Finnish plant materials against selected microbes was conducted in this study. The tests were carried out using diffusion methods with four to nine microbial species (Aspergillus niger, Bacillus subtilis, Candida albicans, Escherichia coli, Micrococcus luteus, Pseudomonas aeruginosa, Saccharomyces cerevisiae, Staphylococcus aureus and Staphylococcus epidermidis). Flavone, quercetin and naringenin were effective in inhibiting the growth of the organisms. The most active plant extracts were purple loosestrife (Lythrum salicaria L.) against Candida albicans, meadowsweet (Filipendula ulmaria (L.) Maxim.), willow herb (Epilobium angustifolium L.), cloudberry (Rubus chamaemorus L.) and raspberry (Rubus idaeus L.) against bacteria, and white birch (Betula pubescens Ehrh.), pine (Pinus sylvestris L.) and potato (Solanum tuberosum. L.) against gram-positive Staphylococcus aureus.     

Study of the Mechanical Properties of Fibers Extracted from Tunisian Agave americana L.

Agave americana L. fibers, the most abundant variety in Tunisia, have a quite important textile potential. This potential is demonstrated by studying the extraction of these fibers from leaves, their physical properties such us fineness or density and their mechanical behavior in tensile tests. In this work, results of a mechanical behavior study of fibers extracted from the Agave americana L. plant are presented. These results deal with the principal and mechanical characteristics of these fibers which are the strain at break, the elasticity modulus and the rupture facture. These results permitted to situate these fibers, compared to the other textile fibers, as materials that can be used in technical applications such as reinforcing composites or geotextile. In order to understand the mechanical properties of these fibers, a correlation study between the properties already cited and the fine structure was done. The obtained results showed that the mechanical properties of Agave americana L. fibers are closely related to the individual fibers deformations and to the natural matrix (lignin and gums) that are linked to these elementary fibers.     

REMOVAL OF LISTERIA SPP. IN A CHEESE FACTORY

A total of 311 samples of 10 mL for liquids and 400-cm² for surfaces were analyzed in a cheese plant in Galicia (Spain) within a period of 10 months (Feb.-Nov. 1996). Forty-six samples were positive for Listeria spp., 36 of which corresponded to L. innocua, 8 to L. monocytogenes and 2 to L. welshimeri. Twenty percent of raw milk samples were Listeria- positive . Listeria was initially detected on some surfaces of production and ripening rooms, but was never detected after replacing old iron machinery with stainless steel machinery, avoiding the movement of the plant equipment outside the factory building, eliminating wooden boards in the ripening chambers and modifying the disinfection system .; Accepted for Publication May 23, 1997     

反渗透膜用于玉米淀粉厂的中水回用的研究

研究了反渗透膜在玉米淀粉厂中水处理中的效果。试验表明,采用反渗透膜处理后的中水COD降低到15mg/L以下,氨氮含量降低到15mg/L以下,全盐量降低到130mg/L以下,各项指标均符合回用水的水质指标。