Antimicrobial activities of therapeutic herbal plants against Listeria monocytogenes and the herbal plant cytotoxicity on Caco-2 cell

Aims: This study investigated the antimicrobial effect of various therapeutic herbal plants on Listeria monocytogenes, and their cytotoxicity effect on mammalian cells. Methods and Results: The extracts from 69 therapeutic herbal plants were used to investigate the effect on the growth inhibition of L. monocytogenes, and their minimal inhibition concentrations and minimal bactericidal concentrations were determined. Among the plants, Psoraleae semen L. (Bogolji) and Sophorae radix L. (Gosam) extracts, which showed obvious antilisterial activity, were examined for the stability to heat, NaCl and acidic condition. Moreover, cytotoxicities of Bogolji and Gosam were tested, using Caco‐2 cells. L. monocytogenes growth was completely inhibited by Bogolji and Gosam extracts at 3·2–6·3 and 50–100 AU ml^?1, respectively, and heat, NaCl and acidic condition did not affect the antilisterial activity of Bogolji and Gosam. Cytotoxic activities were observed only at high concentration (50 AU ml^?1) of Bogolji extract. Conclusion: Bogolji and Gosam could be considered as potential phytochemicals to control L. monocytogenes. Significance and Impact of the Study: Use of therapeutic herbal plants should be useful in controlling L. monocytogenes, because most consumers have better acceptance for phytochemicals than synthetic chemicals.     

Anti‐Campylobacter and resistance‐modifying activity of Alpinia katsumadai seed extracts

Aims

We tested extracts from Alpinia katsumadai seeds for anti‐Campylobacter activity and investigated the roles of the CmeABC and CmeDEF efflux pumps in Campylobacter resistance to these natural phenolics. Additionally, we investigated an A. katsumadai ethanolic extract (AlpE) and other plant extracts as putative efflux pump inhibitors on Campylobacter isolates and mutants in efflux pump genes.

Methods and Results

AlpE showed antimicrobial activity against sensitive and multidrug‐resistant Campylobacter isolates. CmeB inactivation resulted in the greatest reduction in resistance, while cmeF and cmeR mutations produced only moderate effects on minimal inhibitory concentrations (MICs). The chemical efflux pump inhibitors additionally reduced MICs in isolates and mutants, confirming that active efflux is an important mechanism in resistance to AlpE, with additional contributions of other efflux systems. A notable decrease in resistance to tested antimicrobials in the presence of subinhibitory concentrations of AlpE confirms its modifying activity in Campylobacter spp.

Conclusions

AlpE is important anti‐Campylobacter source of antimicrobial compounds with resistance‐modifying activity. At least two of the efflux systems are involved in the resistance to A. katsumadai antimicrobial seed extracts.

Significance and Impact of the Study

This is the first report of antimicrobial and resistance‐modifying activity of AlpE from A. katsumadai seeds, demonstrating its potential in the control of Campylobacter in the food chain.     

松嫩平原旱生芦苇群落土壤呼吸动态及影响因子

为研究松嫩平原旱生芦苇群落土壤呼吸作用的动态变化及其影响因子,于2011年5—10月采用LI-6400土壤呼吸监测系统对旱生芦苇群落土壤呼吸进行连续野外观测,并分析水热因子对土壤呼吸的影响。结果表明:芦苇群落土壤呼吸具有明显的日变化和季节变化特征;其日变化为明显的单峰曲线,土壤呼吸速率峰值出现在中午11:00—13:00;7和8月芦苇群落土壤呼吸作用最强,10月土壤呼吸作用最弱。影响旱生芦苇群落土壤呼吸的主导因子是温度,土壤呼吸与近地表空气温度以及土壤0～10、10～20、20～30cm温度均有显著相关性(P<0.01),而近地表空气温度和土壤表层温度对土壤呼吸的影响最大。在5—10月芦苇群落土壤呼吸温度敏感性Q10值为1.2～1.65,变异系数为15.4%。土壤含水量和近地表空气相对湿度不是影响该地区芦苇群落土壤呼吸的主要因素。     

NaCl和Na2CO3胁迫对桑树幼苗生长和光合特性的影响

以1年生“青龙桑”幼苗为试验材料,研究了中性盐(NaCl)和碱性盐(Na2CO3)胁迫下桑树幼苗的生长和叶片光合特性.结果表明： 盐胁迫明显降低了桑树幼苗的株高、叶片数、生物量和叶片的光合能力.随着Na+浓度的增加,桑树叶片的气孔导度、蒸腾速率、净光合速率、实际光化学效率、电子传递速率和光化学猝灭系数明显降低,过剩光能以非光化学猝灭形式耗散的比例增加,桑树叶片的光能转化效率和光合能力下降.在Na+浓度＜150 mmol·L-1时,桑树幼苗的光合能力和生长受到的抑制较小,通过增加根冠比进一步适应盐胁迫,但这种保护机制随着盐浓度的增加逐渐降低.在Na2CO3胁迫下,＞50 mmol·L-1Na+浓度对桑树的生长和光合能力表现出较强的抑制作用,并随Na+浓度的增加,抑制程度加大.在NaCl＜150 mmol·L-1时,桑树的光合能力主要依赖植株形态和光合代谢双重途径适应中性盐逆境,而在NaCl浓度＞150 mmol·L-1和碱性盐胁迫下,其主要依赖光合代谢来适应逆境.     

海草形态、生长的种间差异及其相关生长关系

海草是海洋沉水高等植物,属典型的根茎克隆植物.根状茎直径和分株重分别是其个体大小的第一、二表征指标,个体大小是海草重要的种间识别特征.对海草6个形态构件指标和18个生长指标的综合分析表明:果实大小、单株叶面积、分株重具有显著的种特异性;分株发出的时间差、水平根状茎分枝率、叶年产量、分株寿命和垂直茎分枝率是海草种特异性最强的5个生长动态指标,海草生长动态的差异主要体现在克隆生长能力强弱和分株生活史长短上;大海草趋于游击型克隆构型,而小海草则趋于密集型,但小海草Cymodocea nodosa例外;大海草基株水平扩展能力较小海草差.海草个体大小与生长特征的相关生长关系表明:随个体的增大,海草在有机构件生长上表现出两相邻叶、相邻分株、相邻节发出的时间差延长,分株、叶、茎寿命延长的特点;在克隆生长水平上表现出根状茎节间长变短、延伸速率降低,分枝率和根状茎上年产分株数降低,分枝角度变小和间隔子增大的趋势;在克隆片段水平上表现为生理整合性增强;在种群层面则表现出生物量增大和种群密度降低的特点.因此,海草个体大小对其形态、生长特征、克隆构型、种群密度和生产力起到了决定作用.大小海草不同的形态、生长动态和克隆构型特征导致它们的生存策略及生态功能也不同,这一点可能对海草场修复基础理论研究具有一定的指示作用.     

高寒草原优势种叶片结构变化与生态因子的关系

 为了揭示青藏高原高寒草原优势物种青藏苔草（Carex moorcroftii）和紫花针茅（Stipa purpurea）对高原特殊环境的适应性,该文研究了 它们的叶片结构在自然环境梯度下的变化以及这些变化与生态因子之间的关系。结果表明：这两个物种叶片的大多数结构特征在各个样地间变 化显著,其结构特征与环境因子间存在显著的相关关系。紫花针茅叶肉细胞大小随土壤有效K含量的增高而减小,下表皮细胞厚度和韧皮部面积 随生长季云盖度的增高而增加,单一导管半径和导管平均面积随生长季月均湿度的增加而增大;青藏苔草上表皮细胞厚度随生长季月均最低温 的降低而增厚,泡状细胞厚度（径向直径）随大陆度的增强而增加,上表皮细胞大小随土壤pH值的增大而增大,导管总数和韧皮部面积随土壤 速效P含量的增高而增加。青藏苔草的保护组织、光合组织以及综合指标变异系数明显大于紫花针茅,仅维管组织指标变异系数小于紫花针茅。     

猪IGF2基因外显子3的遗传多态性及遗传效应分析

采用PCR-SSCP方法检测猪胰岛素样生长因子2 (insulin-like growth factor 2,IGF2)基因外显子3多态性,分析其对初生重、断奶重、6月龄重和背膘厚的遗传效应.根据猪IGF2基因的DNA序列（AY044828）设计引物,结果在其扩增片段上检测到多态性,对纯合子进行测序,发现IGF2-ex3-A36T和IGF2-ex3-G109A两个多态性位点,并且这2个多态性位点完全连锁,检测到3种基因型（A36A/G109G,A36T/G109A 和 T36T/A109A）.统计结果表明,基因型在各品种中分布不一致,长白猪和大白猪与莱芜猪、大薄莲猪、沂蒙黑猪和里岔黑猪比较基因型分布差异极显著（Ｐ<0.01）;其它猪种间基因型分布差异均不显著（Ｐ>0.05）.固定效应模型分析结果表明,初生重和背膘厚基因型间差异显著（Ｐ<0.05）,而断奶重和6月龄重基因型间差异不显著（Ｐ>0.05）.最小二乘分析结果表明,A36A/G109G基因型个体同A36T/G109A和 T36T/A109A基因型个体比较初生重和背膘厚的差异显著（Ｐ<0.05）,3种基因型初生重的大小排列顺序为A36A/G109G < A36T/G109A < T36T/A109A,背膘厚的大小排列顺序为A36A/G109G > A36T/G109A >T36T/A109A.因此,推测IGF2基因对个体的初生重和胴体瘦肉率存在一定的影响,将IGF2基因应用于猪育种过程中的标记辅助选择,将可以改善猪肉品质,加快猪的育种进程.     

Entrapment of herbal extracts into biodegradable microcapsules

The microcapsules with entrapped herbal water-soluble extracts of plantain Plantago major and calendula Calendula officinalis L. (PCE) were prepared by layer-by-layer (LbL)-adsorption of carrageenan and oligochitosan onto CaCO₃ microparticles with their subsequent dissolving after the treatment of EDTA. Entrapment of PCE was performed by using adsorption and co-precipitation techniques. The co-precipitation provided better entrapment of PCE into the carbonate matrix compared to adsorption. In vitro release kinetics (AGJ) was studied using artificial gastric juice. Using the model of acetate ulcer in rats it has been demonstrated that PCE released from the microcapsules accelerates gastric tissue repair.     

益智有效抗氧化成分的分离条件的研究

探讨了干柱层析法分离益智渣及益智乙醇提取物的抗氧化成分。实验中采用乙酸乙酯/环己烷(3∶7)、氯仿/甲醇(9∶1)为展开剂依次二次干柱层析分离出抗氧化物质。结果表明,益智渣及益智乙醇提取物均有较强的抗氧化性,益智渣的H2O2清除能力强于益智乙醇提取物。     

连作对丹参生长的障碍效应

通过对1～4年不同连作年限地块丹参生长发育情况进行的连续调查分析,结果表明,连作严重危害丹参生长,主要表现在6～9月,丹参生长期的枯苗率大幅度上升,地上、地下部生长量下降,根系数量、直径和长度减小,产世降低。同时由于有效成分含量降低,根系外观畸形,造成商品率下降,从而影响丹参质量。通过对土壤pH测定发现．丹参连作障碍可能与土壤酸性增加有关。