基于大孔吸附树脂富集法的肿节风粗黄酮纯化研究

[目的]筛选适用于肿节风（Sarcandra glabra）粗黄酮类物质纯化的大孔吸附树脂。[方法]比较12种大孔吸附树脂对肿节风总黄酮的静态吸附率和解吸率,用不同梯度浓度的乙醇洗脱HPD-600大孔吸附树脂,并计算总黄酮回收率和纯度。[结果]HPD-600大孔吸附树脂的回收率为86.56%,纯度可达68.7%。[结论]HPD-600树脂综合性能良好,适用于肿节风粗黄酮类物质的分离纯化。     

吉林省粮食总产量影响因素趋势分析

采用灰色系统理论,对影响吉林省粮食总产量的各因素进行动态灰色关联分析,并运用GM（1,1）模型在对其发展趋势预测的基础上进行趋势关联分析.研究结果动态地反映了吉林省粮食生产发展的趋势,为粮食生产持续发展、科学决策提供理论依据。     

日全食家禽动物行为观察

对日全食时家禽动物行为进行观察,为家禽养殖及其动物行为学提供基础资料。观察日全食时放养鸡、鹅、番鸭、骡鸭及水鸭等家禽的动物行为学变化。结果:日全食时,家禽敏感程度为,鸡最敏感,番鸭次之,鹅第三,骡鸭和水鸭最不敏感。     

超高压处理对豆乳总多酚、类黄酮含量及其抗氧化性的影响

研究了豆乳经超高压处理后,其总多酚、类黄酮含量的变化,并用DPPH法、FRAP法分析了上述处理对豆乳体外抗氧化活性的影响.结果表明:200 MPa处理对豆乳中总多酚无显著影响(P>0.05),300、400、500 MPa处理后的总多酚则显著增加(P<0.05),加热处理后显著下降(P<0.05).400、500 MP...     

2005—2009年生物学期刊的统计与分析

以2005--2009年的生物学期刊为统计源,对其主要计量指标、英文期刊数、地区分布及出版周期进行了分析。结果表明：2005--2009年,生物学期刊的影响因子和总被引频次的平均值呈上升趋势．增长率分别为：11．55％和65．04％;平均影响因子（IF）为1．699,IF≥1的期刊有5种;平均总被引频次（CF）为8024次,CF≥1000次的期刊有13种,占37．70％,2个指标《生态学报》均排第一。61种生物期刊中．英文版期刊比例在逐年上升,至2009年13．11％;生物期刊主要分布在北京（占47．54％）和上海（占16．39％）等地;出版周期以月刊和双月刊为主,其比例达88．52％。生物学期刊整体发展呈上升趋势。但是各刊之间发展极不平衡。     

盐碱胁迫对4个平菇菌丝生长的影响

采用平板培养法,以不同浓度NaCl和pH值对4个平菇菌株进行耐盐碱胁迫试验。结果显示,各菌株对盐碱胁迫的敏感性不同。低盐和低pH值条件下,菌丝生长受影响不显著,当培养基的NaCl浓度大于1%、pH值大于9时,菌丝生长均受到严重抑制,且随着盐浓度和pH值的增加而增大,并呈极显著的负相关。在4个平菇菌株中澳白的耐盐碱能力最强。     

Effect of different biofloc levels on microbial activity,water quality and performance of Litopenaeus vannamei in a tank system operated with no water exchange

In zero-exchange superintensive culture systems, flocculated particles (bioflocs) accumulate in the water column. Consequently, some control over the concentration of these particles must be performed. The objective of this study is to evaluate the effects of three concentrations of bioflocs on microbial activity, selected water quality indicators and performance of Litopenaeus vannamei in a tank system operated with no water exchange. A 44-day study was conducted with juvenile (6.8 g) shrimp stocked in twelve 850 L tanks at a stocking density of 459 shrimp m⁻³. Biofloc levels were expressed as three presets of total suspended solids (TSS) concentrations, as follows: 200 mg L⁻¹ (T200), 400–600 mg L⁻¹ (T400–600), and 800–1000 mg L⁻¹ (T800–1000). TSS levels were controlled by attaching a 40 L settling tank to each culture tank. Reduction of TSS to concentrations close to 200 mg L⁻¹ decreased the time of bacterial cell residence and significantly reduced the nitrification rates in the water (P < 0.05). The tanks in the T200 treatment had a greater variability of ammonia and nitrite (P < 0.05), which led to the need to increase the C:N ratio of the organic substrate to control ammonia through its assimilation into heterotrophic bacterial biomass. But the higher production of heterotrophic bacteria in T200 (P < 0.05) increased the dissolved oxygen demand. Nitrification rates were higher (P < 0.05) in tanks with TSS concentrations above 400 mg L⁻¹, and ammonia and nitrite were significantly lower than in the T200 tanks. We suggest that ammonia and nitrite in the T400–600 and T800–1000 tanks were controlled primarily by nitrifying bacteria, which provided higher stability of these parameters and of dissolved oxygen. Regarding shrimp performance, the reduction of TSS to levels close to 200 mg L⁻¹ was associated with better nutritional quality of bioflocs. Nevertheless, differences in biofloc levels and nutritional quality were not sufficient to affect the weight gain by shrimp. The rate of shrimp survival and the final shrimp biomass were lower (P < 0.05) when the TSS concentrations were higher than 800 mg L⁻¹. Analysis of the shrimps’ gills showed a higher degree of occlusion in the T800–1000 treatment (P < 0.05), which suggests that the shrimp have an intolerance to environments with a solids concentration above 800 mg L⁻¹. Our results show that intermediate levels of bioflocs (TSS between 400 and 600 mg L⁻¹) appear to be more suitable to superintensive culture of L. vannamei since they create factors propitious for maintaining the system’s productivity and stability     

Prophylactic effect of green tea polyphenols against liver and kidney injury induced by fenitrothion insecticide

The ameliorative effect of daily administrated dose of green tea extract (60 mg polyphenols/animal/day) was investigated on albino rats Rattus norvegicus (150-180 gm) intoxicated with 1/30 and 1/60 LD₅₀ fenitrothion organophosphate insecticide for 28 days. Blood samples were taken at 14 and 28 days for further biochemical parameters. Histopathological studies were carried out in the liver and kidney at the end of the experiment. Significant inhibition in plasma cholinesterase (ChE), a biomarker of Ops, was recorded. Damage in the liver and kidney tissues was observed and confirmed with elevation of plasma alanine aminotransferase (ALT), aspartate aminotaransferase (AST), albumin, urea and creatinine, as well as an elevation in the oxidative stress (OS) marker malondialdehyde (MDA). Decrease in total glutathione (GSH) content in erythrocytes and fluctuation in glutathione S-transferase (GST) activity in plasma was also observed. Green tea supplementation (60 mg/animal/day) partially counteracts the toxic effect of fenitrothion on oxidative stress parameters and repairs tissue damage in the liver and kidney, especially when supplemented to 1/60 LD₅₀ intoxicated animals depending on the duration. It seems that enzyme and metabolite markers of these organs need more time to be restored to the control level.     

Arbutus unedo L. leaves as source of phytochemicals with bioactive properties

In recent years the strawberry tree (Arbutus unedo L.) is being gradually replaced by other species with higher economic value. With the ultimate goal of selecting superior genotypes, the present work was initiated to study the antioxidant and antimicrobial activities, and total phenolic content in 19 different genotypes of A. unedo leaves from the Trás-os-Montes region of Portugal.The genotype Bragança 1 contains higher total phenolic content (215.0 mg GAE/g_extract) whereas the Vila Boa 4 genotype shows lower total phenolic content (148.0 mg GAE/g_extract). In both methods tested to evaluate the antioxidant activity, Vila Verde and Donai displayed the highest antioxidant capacity (EC₅₀ values of 0.088 and 0.090 mg/mL, respectively, for DPPH; EC₅₀ values of 0.233 and 0.245 mg/mL, respectively, for reducing power assay) while Vila Boa 2 reported the lowest antioxidant potential (EC₅₀ values of 0.142 and 0.378 mg/mL, respectively, in DPPH and reducing power methods). Linear negative correlations were established between the total phenol contents and the EC₅₀ values for both of the antioxidant activity methods tested. Preliminary assays for antimicrobial potential showed that extracts from A. unedo leaves display antibacterial activity, with MIC values of 1 and 5 mg/mL for some Gram-positive and Gram-negative bacteria, respectively. Taken together, the results suggest that A. unedo leaves are a potential source of natural compounds with valuable bioactive properties that could be explored by the pharmaceutical, chemical and food industries.