浅议慕课及其对精品课程建设的启示

慕课(MOOC)在学习成本低、学习效率高、交互性强等方面受到了广大学习者的青睐,逐渐成为终身学习的一种渠道。精品课程建设是高校教育与教学改革工程必不可少的环节,精品课程建设第二期工程——精品资源共享课正在建设过程中。慕课运行方式对我国精品资源共享课建设具有一定借鉴意义。     

Polymerisation of gluten proteins in developing wheat grain as affected by desiccation

The breadmaking quality of wheat is affected by the composition of gluten proteins and the polymerisation of subunits that are synthesised and accumulated in developing wheat grain. The biological mechanisms and time course of these events during grain development are documented, but not widely confirmed. Therefore, the aim of this study was to monitor the accumulation of gluten protein subunits and the size distribution of protein aggregates during grain development. The effect of desiccation on the polymerisation of gluten proteins and the functional properties of gluten were also studied. The results showed that the size of glutenin polymers remained consistently low until yellow ripeness (YR), while it increased during grain desiccation after YR. Hence, this polymerisation process was presumed to be initiated by desiccation. A similar polymerisation event was also observed when premature grains were dried artificially. The composition of gluten proteins, the ratios of glutenin to gliadin and high molecular weight-glutenin subunits to low molecular weight-glutenin subunits, in premature grain after artificial desiccation showed close association with the size of glutenin polymers in artificially dried grain. Functional properties of gluten in these samples were also associated with polymer size after artificial desiccation.     

Disulphide structure of high-molecular-weight (HMW-) gliadins as affected by terminators

This study aimed at elucidating SS-bonds of HMW-gliadins (HGL) from wheat with the focus on terminators of glutenin polymerisation. HGL from wheat flour extracts non-treated or treated with the S-alkylation reagent N-ethylmaleinimide (NEMI) were compared. HGL from wheat flour Akteur were isolated, hydrolysed with thermolysin and the resulting peptides pre-separated by gel permeation chromatography and analysed by liquid chromatography/mass-spectrometry using alternating electron transfer dissociation/collision-induced dissociation. Altogether, 22 and 28 SS-peptides from samples without and with NEMI treatment, respectively, were identified. Twenty-six peptides included standard SS-bonds of α- and γ-gliadins, high-molecular-weight and low-molecular-weight glutenin subunits. Eleven SS-bonds were identified for the first time. Fifteen peptides unique to HGL contained cysteine residues from gliadins with an odd number of cysteines (ω5-, α- and γ-gliadins). Thus, gliadins with an odd number of cysteines, glutathione and cysteine had acted as terminators of glutenin polymerisation. Decisive differences between samples without and with NEMI treatment were not obvious showing that the termination of polymerisation was already completed in the flour. The two HGL samples, however, were different in the majority of ten peptides that included disulphide-linked low-molecular-weight (LMW) thiols such as glutathione and cysteine with the former being enriched in the non-treated HGL-sample.     

Effect of starvation on the performance of baby octopus (Robsonella fontaniana) paralarvae

The aim of this study was to evaluate the effect of short‐ and long‐term starvation on paralarvae from hatching and compare to fed paralarvae. In the continuous starvation treatments, paralarvae at hatching were left without food as independent treatments for 5, 8, 9, 10, 11, 12, 13 and 15 days. In the fed treatments, the newly hatched paralarvae were fed for five and eight days; then each group was left in starvation as independent treatments for 3, 5 and 7 days. After any experimental starvation period, the paralarvae were fed for five more days to evaluate their recovery. Paralarvae exposed to continuous starvation from hatching endured up to 8 days after hatching (8 SDAH) showing significant recovery. Its survival decreased proportionally to the days of starvation, without any recovery after 12 DAH. Fed paralarvae (5 and 8 FDAH), resulted in significant differences accordingly to the length of the starvation period. Paralarvae left under permanent starvation showed a noticeable decrease in their arm/mantle length ratio and an atrophy of the digestive gland was observed. Amino acids were used primarily as energy source by paralarvae, particularly in the second week of starvation. It is discussed the critical age to avoid deleterious effects of starvation on paralarvae.     

浸种和外源激素处理对毛马齿苋种子发芽的影响

为提高毛马齿苋种子播种出苗率，分析不同时间浸种以及采用GA3、NAA和6-BA 3种外源激素处理对其种子发芽的影响。结果表明：浸种处理没有提高毛马齿苋种子的发芽势和发芽率的效果；GA3、NAA和6-BA三种激素浸种处理均能提高毛马齿苋种子的发芽势和发芽率；最适宜的浸种浓度分别为GA3 30 mg/L、10～20 mg/L NAA或6-BA 30 mg/L。其中GA3有效浓度范围较宽泛，建议采用，但GA3处理不能解除该种子发芽的需光性。     

A new lean no time test baking method with improved discriminating power

In response to customer concerns related to gluten strength in commercial baking, the Canadian Grain Commission assessed whether the Canadian Short Process (CSP) test bake method was generating useful data related to intrinsic strength of wheat varieties. Assessment of CSP loaf volume data for Canadian variety trials spanning 2003 to 2013 showed very little correlation with dough strength parameters as measured by farinograph and extensigraph. A lean no time (LNT) test baking method was developed that can better discriminate genotypes and provide objective indicators of the effect of intrinsic dough strength on baking quality. From early method development, through method validation and verification using diverse sets of samples targeting different Canadian wheat classes and grown in three different crop years, results showed the LNT method to be more discriminating and easily adopted by other laboratories. In 2015, the LNT method was adopted as the method of choice in future Canadian variety registration trials. The LNT method is fast, simple and well-suited to high throughput test baking conditions encountered in the evaluation of large numbers of breeder lines. A new objective parameter, loaf top ratio, was also introduced and found to correlate well with dough strength and dough handling properties.     

高密度二氧化碳对食品中蛋白质结构及其加工特性影响研究进展

非热加工技术已广泛应用于食品加工行业，高密度二氧化碳（dense phase carbon dioxide，DPCD）加工技 术作为一种新型的非热加工技术，因其无毒无害、能耗低、对食品品质影响小等特点，成为国内外食品加工技术研 究的焦点。蛋白质作为食品的重要组成成分，直接影响食品的风味、质构及营养。本文简要介绍DPCD加工技术概 况和特点，总结关于DPCD对蛋白质结构及加工特性影响和DPCD钝酶作用的最新研究进展，展望了DPCD加工技术 的发展前景，为今后非热加工技术应用于食品加工提供重要研究思路。     

江苏盐城首次记录到彩鹮

2020年5月4日在江苏盐城大丰麋鹿国家级自然保护区(120°47′—120°53′E,32°59′—33°03′N)记录到3只彩鹮。栖息地为一处浅滩水塘,3只彩鹮于水中觅食。以往曾宣布彩鹮在国内绝迹,本次记录填补了彩鹮在本地区的分布空白,证实了彩鹮在江苏省仍有分布。这一纪录或许说明本地区栖息地得到了有效的改善。     

长三角地区设施蔬菜施肥现状及土壤性状研究

针对近年来长三角地区设施菜地规模化程度逐渐加剧,对规模化和分散型种植方式开展调研,阐明不同种植方式下的施肥现状、土壤理化性状的变化情况。本文采用调查问卷和现场取样的调查方法,在以上海市松江区和苏州市支塘镇为代表的规模化种植区以及以宜兴市周铁镇、常州市武进区为代表的分散型种植区开展有机肥和化肥的施肥情况调查,并分析土壤pH、EC以及土壤碱解氮、有效磷、速效钾等速效养分含量。结果表明,规模化种植方式周年肥料施用总量比分散型种植低17.8%,其中有机肥比分散型种植低843.8 kg/ha,化肥比分散型种植高34.5 kg/ha；与分散型种植方式相比,规模化种植周年投入的氮肥(N)低了41.8%,而磷肥(P₂O₅)和钾肥(K₂O)分别高了6.8%和38.3%。在土壤的理化性状上,规模化种植方式下的土壤酸化、盐渍化问题较分散型种植严重,土壤pH和电导率分别为5.2和490.7 μS/cm,土壤碱解氮、有效磷和速效钾平均含量为286.3 mg/kg、322.3 mg/kg和374.2 mg/kg,比分散型种植分别高了123.9%、26.4%和68.7%。鉴于此,规模化种植区应大力推广叶面肥和有机水溶肥水肥一体化等减施增效措施,可能有利于维持规模化种植下设施土壤的可持续利用。