Soil organic matter beyond molecular structure Part I: Macromolecular and supramolecular characteristics

This contribution reviews and discusses structural aspects of soil organic matter (SOM) and humic substances (HS) with special respect to the macromolecular and the supramolecular view. It can be concluded that (1) dissolved humic acids behave as supramolecular associations of relatively small molecules with an enormous flexibility of reaction of environmental conditions, (2) multivalent cations may increase the apparent molecular weight by the formation of coordinative crosslinks in dissolved and undissolved natural organic matter (NOM), (3) sorption nonlinearity in solid humic acids and SOM may be due to polymer properties of NOM, (4) sorbates affect sorbent characteristics of SOM, and (5) hysteresis and conditioning effects in SOM can up to now best be explained with the polymer analogy. A distinct polydispersivity of SOM over a wide range of molecular masses is to be assumed. The supramolecular and the macromolecular models were derived from humic acids with different composition and on the basis of different sample states. Although the supramolecular model has not explicitely been shown for unfractionated DOM, the combination of all discussed studies suggests supramolecular as well as macromolecular characteristics of NOM. Neither macromolecules nor small molecules can be fully excluded in solid and dissolved SOM. Microregions with different properties provide different types of sorption sites. SOM is suggested to be regarded as amorphous material. This point of view is not restricted to high molecular masses and may supplement our understanding of SOM by the model of physical aging.     

顶孢霉Ahy1菌株孢子乳悬剂的配方筛选

采用室内生物测定的方法,从7种食用油,5种乳化剂,5种紫外保护剂和3种抗生素中筛选适合于顶孢霉Ahy1分生孢子粉乳悬剂的助剂配方。结果表明,姜油与顶孢霉Ahy1分生孢子粉混合贮130 d,分生孢子的萌发率最高,对孢子的生物活性无明显影响。在乳化剂、紫外保护剂和抗生素的筛选中, 综合与Ahy1分生孢子粉的湿润力和生物相容性,选择吐温〖CD*2〗80与OP〖CD*2〗10的混剂为Ahy1孢子悬浮剂的乳化剂,十二烷基硫酸钠为湿润剂,腐植酸为紫外保护剂,硫酸链霉素为抗生素。以上助剂与顶孢霉孢子粉均有良好的生物相容性。     

香菇多糖的超滤分离及保润性能研究

采用溶剂提取法从香菇中提取香菇多糖,通过酶解法和Seveg法除去多糖中的蛋白质,得到香菇精多糖。通过超滤分离手段将香菇多糖按照分子量的大小分成4个组分,LE1、LE2、LE3和LE4。将4种香菇多糖以不同重量比添加到烟丝中,分别测量其在30%和80%湿度下的平衡含水率,表征其物理保润性能。结果表明,添加香菇多糖能明显提升烟丝在干燥环境下的平衡含水率,并降低潮湿环境下的平衡含水率。随着香菇多糖分子量的增加,其在潮湿环境下的防潮性能不断提升,而干燥环境下的保湿性能先增加后降低。     

阿片对动物组织大分子成分的影响

阿片系统是调节机体生理活动的系统之一。根据近几十年进行的调查,阿片被认为在控制家畜和其他种类动物生长中起着重要作用。然而有关阿片对家畜组织重量及组织DNA、RNA和蛋白质影响的研究甚少。阐述了阿片对豚鼠、负鼠以及真螈组织大分子成分的影响。虽然阿片是否影响组织功能尚不清楚,但是阿片可以抑制小白鼠和人类的免疫功能。     

钼对烤烟不同品种叶绿素荧光、抗氧化及氮代谢酶活性的影响

利用营养液水培技术,以晚花K326和南江3号烟草品种为试验材料,于施钼和缺钼2个处理条件下水培30 d后,研究其对烤烟不同品种叶绿素荧光、抗氧化及氮代谢关键酶活性的影响。结果表明,和缺钼相比,晚花K326和南江3号品种的施钼烟株农艺性状明显增强,晚花K326和南江3号品种在根长、茎围和鲜重方面增幅分别为4.48%、26.52%、13.06%和7.13%、6.38%、5.52%。两个品种施钼烟叶的最大荧光产量Fm(maximal-fluorescence)和最大光化学量子产量Fv/Fm(optimal/maximal quanturn yield of PSⅡ)较缺钼都有所增加,晚花K326和南江3号增幅分别为10.33%、13.70%和13.52%、7.01%。晚花K326的过氧化氢酶CAT(Cat from micrococcus lysodeikticus)、过氧化物酶POD(Peroxidase)和超氧化物歧化酶SOD(Superoxide dismutase)活性较缺钼条件下显著增强,增幅为145.83%、90.72%和5.58%;南江3号的SOD活性较缺钼条件下增强,增幅5.76%。施钼烟草硝酸还原酶(Nitrate reductase,NR)活性较缺钼烟草有所增加,晚花K326和南江3号增幅分别为107.41%和16.00%,南江3号品种差异显著,晚花K326缺钼与南江3号缺钼差异显著。施钼烟草的谷氨酰胺合成酶(glutamine synthetase,GS)活性提高,晚花K326增幅较大;施钼晚花K326与南江3号差异显著,南江3号品种差异显著。施钼烟草亚硝酸盐含量均比缺钼烟草低,晚花K326和南江3号品种均表现为差异显著。综上,施钼不同程度促进了2个品种的生长发育,光合能力、抗氧化性和氮代谢增强,对晚花K326品种幼苗影响较为显著。     

2种保润剂的保湿性能和保润效果比较研究

为改善烟草制品的耐加工性能,对丙二醇、PCAK-1和空白样品的保湿性能及其对烟丝的保润效果进行对比试验,并对加料卷烟进行感官评吸。结果表明:与空白样品相比,丙二醇、PCAK-1的保湿率均有很大程度的提高。加入保润剂3～4 d,烟丝的含水率均有所回升,之后又有不同程度的下降;丙二醇、PCAK-1保润剂均对卷烟的吸味无负面影响。     

Effect of Partial Replacement of Sucrose With Humectant in the Osmotic Solution on the Characteristics of Osmo-Dried Cantaloupe

The effect of osmotic solutions consisting of sucrose and humectants (sorbitol and glucose syrup) on the quality of osmo-dried cantaloupe was investigated. The ratios between sucrose and each humectant were varied (90:10, 80:20, and 70:30). The increments in water loss and solid gain were observed with increasing the sorbitol ratio in the mixtures, while increasing the glucose syrup ratio in the mixture decreased water loss and solid gain during osmotic dehydration. All samples immersed in the osmotic solution containing sucrose and sorbitol had higher L* and lower a* values than those of samples immersed in the osmotic solution containing sucrose and glucose syrup. The hardness tended to decrease with increasing sorbitol and glucose syrup ratio in the osmotic solution. In addition, the increment of all humectants ratios caused a decrease in water activity (a_w). The reduction in vitamin C, phenolic content, and 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity was observed with increasing sorbitol concentration in the osmotic solution. Moreover, an increase in all humectant ratios could reduce 5-hydroxymethylfurfural content in the final product. The sensory attributes, including color, texture, and overall acceptability, were found to be better in the case of sucrose-sorbitol treated samples when compared to those of the sucrose-glucose syrup treated samples.     

灰霉菌及其胞外大分子对不同植物的伤害鉴定

[目的]探究灰霉菌及其胞外大分子毒素对不同植物的伤害情况。[方法]以灰霉菌分生孢子及其分泌的胞外大分子毒素为试验材料,选取21科29属30种植物为供试植物,观察了灰霉菌对其侵染性以及灰霉菌分泌至培养液中的大分子毒素对其伤害情况。[结果]30种供试植物中既被灰霉菌侵染又被毒素损害的植物有17种,占全部植物的56.7%;有2种植物均不能被灰霉菌侵染也不能被毒素伤害。[结论]为进一步了解植物病原真菌毒素致病机制提供了借鉴。     

两亲性大分子季铵盐对水稻纹枯病菌抑菌活性表征方法研究

【目的】为两亲性大分子季铵盐对植物病原真菌的抑菌活性表征方法的选择提供参考。【方法】 分别采用生长速率法和菌丝称重法表征一类新型两亲性大分子季铵盐〔聚二甲基硅氧烷 -b- 聚丙烯酸酯季铵盐 嵌段共聚物，PDMS-b-(PDMAEMA-BC)，简称 Six-Q5〕、亲水性大分子季铵盐（PQD-BC）和小分子季铵盐（BC） 对水稻纹枯病菌（Rhizoctonia solani）的抑菌活性。【结果】生长速率法可用于 PQD-BC 和 BC 的抑菌活性表征， 但不适合 Six-Q5 的抑菌活性表征；菌丝称重法可用于 3 类季铵盐抑菌活性的表征。PDMS 嵌段长度适中的 Si5-Q5 对 R. solani 的 IC50 与 IC90 分别为 12、59 μg/mL，其抑菌活性与小分子季铵盐相当。【结论】对于两亲性大分子 季铵盐，菌丝称重法较生长速率法更适合其抑菌活性的表征。     

新型保润剂CPL-NR在卷烟中的应用研究

为改善烟草制品的耐加工性能和品质,对CPL-NR和丙二醇的保湿性能及其在卷烟中的应用效果进行对比研究。结果表明:与丙二醇相比,CPL-NR自身保湿率有一定程度的提高,并可以有效减缓烟丝水分散失;应用CPL-NR对改善香气丰满度和透发性、降低刺激、增加津润感、提高喉部舒适性等方面均有较好效果,对卷烟烟气和常规化学成分指标无负面影响。