Quantifying Aflatoxin B1 in peanut oil using fabricating fluorescence probes based on upconversion nanoparticles

Rare earth doped upconversion nanoparticles convert near-infrared excitation light into visible emission light. Compared to organic fluorophores and semiconducting nanoparticles, upconversion nanoparticles (UCNPs) offer high photochemical stability, sharp emission bandwidths, and large anti-Stokes shifts. Along with the significant light penetration depth and the absence of autofluorescence in biological samples under infrared excitation, these UCNPs have attracted more and more attention on toxin detection and biological labelling. Herein, the fluorescence probe based on UCNPs was developed for quantifying Aflatoxin B₁ (AFB₁) in peanut oil. Based on a specific immunity format, the detection limit for AFB₁ under optimal conditions was obtained as low as 0.2 ng·ml^{- 1}, and in the effective detection range 0.2 to 100 ng·ml^{- 1}, good relationship between fluorescence intensity and AFB₁ concentration was achieved under the linear ratios up to 0.90. Moreover, to check the feasibility of these probes on AFB₁ measurements in peanut oil, recovery tests have been carried out. A good accuracy rating (93.8%) was obtained in this study. Results showed that the nanoparticles can be successfully applied for sensing AFB₁ in peanut oil.

Fast and sensitive aflatoxin B1 and total aflatoxins ELISAs for analysis of peanuts, maize and feed ingredients

Aflatoxins are a group of carcinogenic compounds produced by Aspergillus fungi that can grow on different agricultural crops. Both acute and chronic exposure to these mycotoxins can cause serious illness. Due to the high occurrence of aflatoxins in crops worldwide fast and cost-effective analytical methods are required for the identification of contaminated agricultural commodities before they are processed into final products and placed on the market. In order to provide new tools for aflatoxin screening two prototype fast ELISA methods: one for the detection of aflatoxin B₁ and the other for total aflatoxins were developed. Seven monoclonal antibodies with unique high sensitivity and at the same time good cross-reactivity profiles were produced. The monoclonal antibodies were characterized and two antibodies showing IC₅₀ of 0.037 ng/mL and 0.031 ng/mL for aflatoxin B₁ were applied in simple and fast direct competitive ELISA tests. The methods were validated for peanut matrix as this crop is one of the most affected by aflatoxin contamination. The detection capabilities of aflatoxin B₁ and total aflatoxins ELISAs were 0.4 μg/kg and 0.3 μg/kg for aflatoxin B₁, respectively, which are one of the lowest reported values. Total aflatoxins ELISA was also validated for the detection of aflatoxins B₂, G₁ and G₂. The application of the developed tests was demonstrated by screening 32 peanut samples collected from the UK retailers. Total aflatoxins ELISA was further applied to analyse naturally contaminated maize porridge and distiller's dried grain with solubles samples and the results were correlated with these obtained by UHPLC-MS/MS method.

Low vitamin B12 levels among newly-arrived refugees from Bhutan, Iran and Afghanistan : a multicentre Australian study

Background: Vitamin B12 deficiency is prevalent in many countries of origin of refugees. Using a threshold of 5% above which a prevalence of low Vitamin B12 is indicative of a population health problem, we hypothesised that Vitamin B12 deficiency exceeds this threshold among newly-arrived refugees resettling in Australia, and is higher among women due to their increased risk of food insecurity. This paper reports Vitamin B12 levels in a large cohort of newly arrived refugees in five Australian states and territories. Methods: In a cross-sectional descriptive study, we collected Vitamin B12, folate and haematological indices on all refugees(n = 916; response rate 94% of eligible population) who had been in Australia for less than one year, and attended one of the collaborating health services between July 2010 and July 2011. Results: 16.5% of participants had Vitamin B12 deficiency (,150 pmol/L). One-third of participants from Iran and Bhutan, and one-quarter of participants from Afghanistan had Vitamin B12 deficiency. Contrary to our hypothesis, low Vitamin B12 levels were more prevalent in males than females. A higher prevalence of low Vitamin B12 was also reported in older age groups in some countries. The sensitivity of macrocytosis in detecting Vitamin B12 deficiency was only 4.6%. Conclusion: Vitamin B12 deficiency is an important population health issue in newly-arrived refugees from many countries. All newly-arrived refugees should be tested for Vitamin B12 deficiency. Ongoing research should investigate causes,treatment, and ways to mitigate food insecurity, and the contribution of such measures to enhancing the health of the refugee communities.

Identification of eusynstyelamide B as a potent cell cycle inhibitor following the generation and screening of an ascidian-derived extract library using a real time cell analyzer

Ascidians are marine invertebrates that have been a source of numerous cytotoxic compounds. Of the first six marine-derived drugs that made anticancer clinical trials, three originated from ascidian specimens. In order to identify new anti-neoplastic compounds, an ascidian extract library (143 samples) was generated and screened in MDA-MB-231 breast cancer cells using a real-time cell analyzer (RTCA). This resulted in 143 time-dependent cell response profiles (TCRP), which are read-outs of changes to the growth rate, morphology, and adhesive characteristics of the cell culture. Twenty-one extracts affected the TCRP of MDA-MB-231 cells and were further investigated regarding toxicity and specificity, as well as their effects on cell morphology and cell cycle. The results of these studies were used to prioritize extracts for bioassay-guided fractionation, which led to the isolation of the previously identified marine natural product, eusynstyelamide B (1). This bis-indole alkaloid was shown to display an IC50 of 5 μM in MDA-MB-231 cells. Moreover, 1 caused a strong cell cycle arrest in G2/M and induced apoptosis after 72 h treatment, making this molecule an attractive candidate for further mechanism of action studies.

Adaptation of the Australian core food groups to enable planning of vegan and lactovegetarian diets

This work demonstrates how the Australian core food groups system can be modified to enable the planning of vegan and lactovegetarian diets as well as omnivorous diets. In the modified version the cereals, vegetables and fruits groups remain the same as in the core food groups system, while the meat group is replaced with legumes, soya products, nuts and seeds. The milk group becomes milk or fortified soya milk, to allow for both lactovegetarian and vegan diets. The core food groups standard of 70% of the recommended dietary intake was adopted as a target for determining recommendations on the minimum number of serves from each food group. As found in the development of the core food groups system, zinc was the most limiting nutrient. Vitamin B 12 and calcium were other limiting nutrients in the vegan and lactovegetarian guides. The number of serves from each group required to meet 70% of the applicable recommended dietary intake has been calculated for children from four years old, adult men and women and pregnant and lactating women. It was found that the number of serves from each food group required in the vegan and lactovegetarian planning guides was in most cases similar to the number of serves of corresponding core food groups specified for a particular population group. This suggests that the vegan and lactovegetarian planning guides could be incorporated into a modified core food groups planning guide. Such a guide would cater for the general omnivorous population as well as for those seeking to avoid meat and/or dairy products. (Aust J Nutr Diet 1999:56:22-30) Key words: vegan, vegetarian, food guide, food groups, dietary planning.

Clinical relevance of MTHFR, eNOS, ACE, and ApoE gene polymorphisms and serum vitamin profile among Malay patients with ischemic stroke

Background The purpose of this study was threefold. First, it was to determine the relationship between serum vitamin profiles and ischemic stroke. The second purpose was to investigate the association of methylenetetrahydrofolate reductase (MTHFR), endothelial nitric oxide synthase (eNOS), angiotensin converting enzyme (ACE), and apolipoprotein-E (ApoE) gene polymorphisms with ischemic stroke and further correlate with serum vitamin profiles among ischemic stroke patients. The third purpose of the study was to highlight the interaction of MTHFR and eNOS haplotypes with serum vitamin profiles and ischemic stroke risks. Methods Polymorphisms of these genes were analyzed in age-, sex-, and ethnicity-matched case–controls (n = 594); serum vitamin profiles were determined using immunoassays. Results The MTHFR 677C>T, 1298A>C, eNOS intron 4a/b, and ApoE polymorphisms were significantly associated with the increased risk of ischemic stroke. Elevated serum homocysteine and vitamin B12 levels were associated with MTHFR 677C>T and eNOS intron 4a/b polymorphisms. The ApoE and eNOS −786T>C polymorphisms were associated with increased serum vitamin B12 levels. However, none of the polymorphisms influenced serum folate levels except for the MTHFR 1298A>C. Different patterns of MTHFR and eNOS haplotypes tend to affect serum vitamin profiles to different degrees, which contribute to either different susceptibility risk or protective effect on ischemic stroke. Overall, increased levels of serum homocysteine and vitamin B12 levels were associated with higher risk of ischemic stroke in the investigated population. Conclusions The present study suggests that the genotypes and haplotypes of MTHFR 677C>T and eNOS intron 4a/b polymorphisms are potential serum biomarkers in the pathophysiological processes of ischemic stroke, by modulating homocysteine and vitamin B12 levels.

Biotin-conjugated tumour-targeting photocytotoxic iron(III) complexes

Iron(III) complexes FeL(B)] (1-4) of a tetradentate phenolate-based ligand (H3L) and biotin-conjugated dipyridophenazine bases (B), viz. 7-aminodipyrido 3,2-a: 2',3'-c]-phenazine (dppza in 1), (N-dipyrido3,2-a: 2',3'-c]-phenazino) amidobiotin (dppzNB in 2), dipyrido 3,2-a: 2',3'-c]-phenazine-11-carboxylic acid (dppzc in 3) and 2-((2-biotinamido) ethyl) amidodipyrido 3,2-a: 2',3'-c]-phenazine (dppzCB in 4) are prepared, characterized and their interaction with streptavidin and DNA and their photocytotoxicity and cellular uptake in various cells studied. The high-spin iron(III) complexes display Fe(III)/Fe(II) redox couple near -0.7V versus saturated calomel electrode in dimethyl sulfoxide-0.1M tetrabutylammonium perchlorate. The complexes show non-specific interaction with DNA as determined from the binding studies. Complexes with appended biotin moiety show similar binding to streptavidin as that of free biotin, suggesting biotin conjugation to dppz does not cause any loss in its binding affinity to streptavidin. The photocytotoxicity of the complexes is tested in HepG2, HeLa and HEK293 cell lines. Complex 2 shows higher photocytotoxicity in HepG2 cells than in HeLa or HEK293, forming reactive oxygen species. This effect is attributed to the presence of overexpressed sodium-dependent multi-vitamin transporters in HepG2 cells. Microscopic studies in HepG2 cells show internalization of the biotin complexes 2 and 4 essentially occurring by receptor-mediated endocytosis, which is similar to that of native biotin and biotin fluorescein isothiocyanate conjugate.

Successful data recovery from oscillation photographs containing strong polycrystalline diffraction rings from an unknown small-molecule contaminant: preliminary structure solution of Salmonella typhimurium pyridoxal kinase (PdxK)

Pyridoxal kinase (PdxK; EC 2.7.1.35) belongs to the phosphotransferase family of enzymes and catalyzes the conversion of the three active forms of vitamin B-6, pyridoxine, pyridoxal and pyridoxamine, to their phosphorylated forms and thereby plays a key role in pyridoxal 5 `-phosphate salvage. In the present study, pyridoxal kinase from Salmonella typhimurium was cloned and overexpressed in Escherichia coli, purified using Ni-NTA affinity chromatography and crystallized. X-ray diffraction data were collected to 2.6 angstrom resolution at 100 K. The crystal belonged to the primitive orthorhombic space group P2(1)2(1)2(1), with unitcell parameters a = 65.11, b = 72.89, c = 107.52 angstrom. The data quality obtained by routine processing was poor owing to the presence of strong diffraction rings caused by a polycrystalline material of an unknown small molecule in all oscillation images. Excluding the reflections close to powder/polycrystalline rings provided data of sufficient quality for structure determination. A preliminary structure solution has been obtained by molecular replacement with the Phaser program in the CCP4 suite using E. coli pyridoxal kinase (PDB entry 2ddm) as the phasing model. Further refinement and analysis of the structure are likely to provide valuable insights into catalysis by pyridoxal kinases.

Evaluation of chemical tests for the quality of prawns

The object of this study was to determine the value of physical, bacteriological and chemical tests used to find out and compare the indices of quality of prawns stored at 0°C and at 18°C. pH value, nature of drip, the total bacterial count, presence or absence of tryptophan, trimethylamine content, glycogen, lactic acid, vitamins such as thiamin, riboflavin and niacin were estimated periodically to evaluate the quality of prawns stored at 0°C, whereas in addition to organoleptic changes, pH, bacterial count, nature of growth in peptone water, soluble protein in salt solution and loss of moisture, glycogen, lactic acid, and changes in vitamin B contents were noted periodically for prawns stored at -l8°C. Riboflavin and niacin were not affected appreciably but the retention of thiamin in prawns was very low.

冬小麦抗寒性和光合作用对增强UV-B辐射与温度交互作用的响应

人类活动产生的氯氟烃化合物破坏了大气臭氧层，导致了到达地球表面的UV-B辐射大幅度增加。UV-B辐射增强可以影响到植物的生长、形态与发育等各个方面，因此有关增强UV-B辐射对植物的影响，及其与许多环境因子复合作用的研究都已经广泛开展。但是增强UV-B辐射与温度，特别是与低温的相互作用的研究报道很少。在北半球的晚秋至早春这段时期里，一些越冬生长的植物将面临着UV-B辐射增强和低温的双重胁迫，因此，迫切需要进行UV-B辐射和低温生长环境下植物的响应及其机制的研究。 以人工气候生长室中生长的冬小麦(Triticum aestivum)幼苗为试验材料，研究了低剂量（4.2 kJ m-2 d-1 UV-BBE，LUVB）和较高剂量（7.0 kJ m-2 d-1 UV-BBE，HUVB）UV-B辐射处理对20/16℃条件下幼苗抗寒力的交叉适应性及其抗氧化系统的反应;同时还研究了在两种生长温度（25/20℃和10/5℃）条件下，低剂量（4.2 kJ m-2 d-1 UV-BBE，LUVB）和超高剂量（10.3 kJ m-2 d-1 UV-BBE，SHUVB）UV-B辐射处理幼苗的生长速率、光合与荧光参数、叶黄素循环色素、抗氧化系统、以及抗寒性和酚类物质等生理反应，以期阐明不同温度条件下生长的冬小麦对UV-B辐射的生长、光合作用以及抗寒性响应与适应机制。主要结果如下： 1.在LUVB辐射处理下，在20/16℃和25/20℃条件下生长的冬小麦幼苗LT50值都显著降低，HUVB辐射处理对在20/16℃条件下生长的幼苗LT50值也可以显著降低，而SHUVB辐射对25/20℃条件下生长的幼苗LT50值没有显著影响。但是，LUVB和SHUVB辐射处理都导致了10/5℃条件下生长的幼苗LT50值的显著增加。表明适当的UV-B辐射能增强较高温度（20/16℃或25/20℃）条件下冬小麦幼苗的抗寒力，即表现出对冷冻低温的交叉适应性，但低温（10/5℃）生长条件却削弱了UV-B辐射下冬小麦的抗寒能力。 2.在20/16℃条件下接受UV-B辐射预处理的幼苗在-6℃条件下冷冻胁迫6 h再缓慢恢复6 h后，与未进行UV-B辐射处理的对照相比，其叶片过氧化氢酶（CAT）、愈创木酚过氧化物酶（GPX）、谷胱甘肽还原酶（GR）活性，谷胱甘肽氧化还原比例（GSH/GSSG）都显著提高，而由硫代巴比妥酸反应物质（TBARS）代表的膜质过氧化程度显著低于对照。此外，UV-B辐射期间处理幼苗的H2O2含量较对照显著增加，而冷冻恢复以后却明显低于对照。表明UV-B辐射诱导的抗寒力的提高应该与冷冻恢复后植株体内抗氧化系统的上调表达有关，H2O2可能参与了UV-B辐射对低温的交叉适应的信号传导。 3.除25/20℃生长条件下的LUVB处理的小麦幼苗外，UV-B辐射显著降低幼苗的相对生长速率（RGR）、净光合速率（Pn）、光系统II最大量子产量（Fv/Fm）、光系统II实际量子产量（(F΄m−Fs)/F΄m）以及光化学淬灭（qP），但是UV-B辐射并不影响叶片胞间CO2浓度（Ci），而且冬小麦幼苗生长和光合作用的抑制被增加的UV-B辐射剂量和降低的温度加强。UV-B辐射引起的光抑制由非气孔限制所导致，而且主要与PS II光化学效率降低有关。 4.UV-B辐射显著增加了两个温度条件（20/16℃或25/20℃）下生长的冬小麦幼苗叶黄素循环过程中紫黄素（V）的合成，但抑制了V向玉米黄质（Z）的转化，从而造成了对照与LUVB辐射处理幼苗之间的叶片中脱环氧化比例（DEPS）和NPQ无显著性差异，但SHUVB辐射处理幼苗叶片中DEPS和NPQ显著降低。因此，在本试验条件下，增强UV-B辐射处理的冬小麦可能并不通过热耗散形式形成光保护机制，光抑制形成的过剩激发能的耗散可能更多地通过代谢途径来实现。 5.UV-B辐射处理提高了在25/20℃条件下幼苗的超氧化物歧化酶（SOD）、抗坏血酸过氧化物酶（APX）和GR等活性，以及抗坏血酸氧化还原比例（AsA/DHA）和GSH/GSSG;但是在10/5℃下，UV-B辐射除了导致SOD和CAT活性升高之外，对APX活性和AsA/DHA并不产生明显影响，但GPX和GSH/GSSG则显著降低。说明UV-B辐射幼苗的抗氧化系统在较高生长温度下显著地增强，而在低温10/5℃下被严重地削弱或降低，即低温阻止了代谢途径的光保护机制的正常运转。 6.多酚物质在UV-B辐射或低温10/5℃条件下都能显著地累积，且在UV-B辐射和低温复合作用下增加尤其显著，表明多酚物质在两个温度生长条件下特别是低温条件下都参与了对UV-B辐射幼苗的保护。 7.在高温条件下仅仅SHUVB处理的幼苗TBARS含量显著增加，而低温10/5℃条件下两个UV-B辐射处理都非常显著地上升，说明与高温生长条件相比较，低温加重了UV-B辐射引起的氧化胁迫，低温10/5℃条件下幼苗多酚的增加以及抗氧化系统的部分增强都没有能阻止UV-B辐射对幼苗的伤害。

Przewalskin B, a novel diterpenoid with an unprecedented skeleton from Salvia przewalskii maxim

[GRAPHIC] Przewalskin B (1), a novel diterpenoid possessing a unique skeleton, was isolated from a Chinese medicinal plant Salvia przewalskii. Its structure and relative stereochemistry were elucidated by extensive NMR analysis and a single-crystal X-ray

肉、奶牛B超活体取卵方法

本发明涉及一种肉、奶牛B超活体取卵方法，属生物技术领域。本方法的吸卵真空泵的压力为50-90mmHg，吸卵液为含0.5-1％,青-链霉素和5-10IU肝素的磷酸缓冲液，洗卵液为含5-12％,BCS的磷酸缓冲液和改良的基础培养液-Hepes液；采卵频率为1次/4天/头；穿刺对象为所有直径≥2mm的卵泡；取1-3级的卵母细胞分装、备用；对7-8岁的供体经产牛按程序注射等量的外源性FSH，总量为30-55μg；对≥14岁的老年牛按程序肌肉注射总量为150-200μg的外源性FSH，以提高卵母细胞发育潜能。本发明的优点在于，从活体可重复、无损伤获取卵母细胞；≥2mm直径卵泡作为穿刺对象和每4天1次的取卵频率保证了卵母细胞的质量和发育同步性；用外源性FSH诱导可提高卵母细胞的发育潜能；本方法的取卵效果佳。

从线粒体Cyt b基因探讨红瘰疣螈物种地位的有效性

疣螈属的红瘰疣螈(Tylototriton shanjing)和棕黑疣螈(T.verrucosus)的物种界限一直不清楚.测定了来自中国西南地区14个地点的T.shanjing和T.verrucosus共40只标本的线粒体DNA Cyt b基因(753 bp).结果表明:(1)用邻接法、最大简约法和贝叶斯法等3种系统发育分析法分别重建棕黑疣螈种组系统发育树的拓扑结构不支持T.shanjing是单系群;(2)T.shanjing与T.verrucsus的mtDNA Cyt b序列差异平均值仅为1.2%.未达到种级水平.因此,全部T.shanjing样品都属于同一个物种,即T.verrucosus,不支持T.shanjing的物种地位,T.shanjing为T.verrucosus的同物异名,并建议恢复T.verrucosus的中文名红瘰疣螈.根据基于40个样品Cvt b基因序列的系统发育树和遗传变异以及地理分布,这些红瘰疣螈(T.verrucosus)样品聚为3支,即中国西南地区的红瘰疣螈可分为片马、滇中滇西和滇东南3个地理居群.

银额果蝇的B染色体研究2: 昆明群体的生活力和B染色体的关系

银额果蝇的B染色体在其生长和发育过程中具双重性调节作用。一方面, B染色体以单一的形式存在于单雌系核型中, 即1B或2Bs可刺激生长发育,增强生活力。另一方面, 在单雌系的细胞中存在多条B染色体, 并形成核型多态性, 似乎对生长发育有一定的抑制作用而减弱其生活力。图1表1参5

Molecular epidemiology of the heterosexual HIV-1 transmission in Kunming, Yunnan Province of China suggests origin from the local IDU epidemic

Molecular epidemiological investigation was conducted among injecting drug users (IDUs) (n = 11) and heterosexuals (n = 15) in Kunming, Yunnan Province of China. HIV-1 genotypes were determined based on the nucleotide sequences of 2.6-kb gag-RT region. The distribution of genotypes among IDUs was as follows: CRF07_BC (5/11) and CRF08_BC (5/11); subtype B' (1/11). Similarly, a majority of Kunming heterosexuals (14/15) were infected with CRF07_BC (4/15), CRF08_BC (6/15), or subtype B' (4/15), known to predominate among IDUs in China. This contrasts with trends in the coastal regions of China and surrounding southeastern Asian countries, where CRF01_AE predominates among heterosexuals. The heterosexual HIV-1 epidemic in Kunming thus appears to derive from the local IDU epidemic. Of note, subtype B' was the most prevalent strain among heterosexuals before 1997, while CRF07_BC and CRF08_BC became predominant in 2002, indicating a transition of HIV-1 genotype distribution between the early and the more recent samples from Kunming heterosexuals.