Uncertainties in the determination of pyrrolizidine alkaloid levels in naturally contaminated honeys and comparison of results obtained by different analytical approaches

The contamination of honey with hepatotoxic pyrrolizidine alkaloids (PAs) is a well-known hazard for food safety. While management strategies and controls of the honey industry aim to reduce the PA levels, uncertainties remain with regard to the safety of regionally produced and marketed honey. In addition, a previous study showed large differences of results obtained after various periods of storage and apparent differences between the analytical results of different laboratories. Therefore, this study aimed at examining these uncertainties by monitoring the impact of storage on the PA and PA N-oxide (PANO) content of two freshly harvested honeys and on possible demixing effects caused by pollen settling. Additionally, three analytical approaches – target analysis with matrix-matched calibration or standard addition and a sum parameter method – were applied for a comparative analysis of 20 honeys harvested in summer 2016. All samples originated from Schleswig-Holstein in Northern Germany where the PA plant Jacobaea vulgaris is currently observed on a massive scale. The results of the time series analyses showed that PANO levels markedly decreased within a few weeks and practically reached the LOD 16 weeks after harvest. Tertiary PAs, by contrast, remained stable and did not increase as a consequence of PANO decrease. The experiments on a putative demixing, which may result in a heterogeneous distribution of PAs/PANOs, revealed that there was no such effect during storage of up to 12 weeks. A comparison of the PA/PANO levels obtained by different analytical approaches showed that in some cases the sum parameter method yielded much higher levels than the target approaches, whereas in other cases, the target analysis with standard addition found higher levels than the other two methods. In summary, the results of this study highlight uncertainties regarding the validity and comparability of analytical results and consequently regarding health risk assessment.     

Consumer perception of extruded snacks containing brown rice and dried mushroom

Effects of mushroom type, seasoning and health benefit information (HBI) on consumers’ saltiness expectation, sensory liking, elicited emotions and purchase intent (PI) of extruded snacks were investigated. Five snacks were evaluated: straw mushroom (Volvariella volvacea) extrudates without (SME) or with seasoning (SMES), phoenix mushroom (Pleurotus pulmonarius) extrudates without (PME) or with seasoning (PMES), and the control without mushroom and seasoning. Hedonic scores and positive emotions were generally higher for seasoned mushroom-containing snacks (SMES and PMES) with 65% and 75.83% of consumers reporting willingness to purchase, respectively, after receiving HBI. Bored, interested and satisfied were identified as significant emotional predictors for PI odds. Flavour, saltiness, overall liking, bored, good and interested were critical attributes, differentiating snacks. This study demonstrated that sensory liking and PI of extruded brown rice-based snacks containing mushroom could be improved through savoury seasoning addition, which also allowed saltiness expectations to be met.     

Chemistry and Toxicology of Major Bioactive Substances in Inocybe Mushrooms

Mushroom poisoning has always been a threat to human health. There are a large number of reports about ingestion of poisonous mushrooms every year around the world. It attracts the attention of researchers, especially in the aspects of toxin composition, toxic mechanism and toxin application in poisonous mushroom. Inocybe is a large genus of mushrooms and contains toxic substances including muscarine, psilocybin, psilocin, aeruginascin, lectins and baeocystin. In order to prevent and remedy mushroom poisoning, it is significant to clarify the toxic effects and mechanisms of these bioactive substances. In this review article, we summarize the chemistry, most known toxic effects and mechanisms of major toxic substances in Inocybe mushrooms, especially muscarine, psilocybin and psilocin. Their available toxicity data (different species, different administration routes) published formerly are also summarized. In addition, the treatment and medical application of these toxic substances in Inocybe mushrooms are also discussed. We hope that this review will help understanding of the chemistry and toxicology of Inocybe mushrooms as well as the potential clinical application of its bioactive substances to benefit human beings.     

Natural occurrence of Fusarium toxins in peanut,sorghum and maize from Mysore (India)

Peanut, sorghum and maize samples were collected from the wholesale market in Mysore, India, over a period of one year (October 1984 to September 1985). The samples were analysed for the natural occurrence of T-2 toxin (T-2), diacetoxyscirpenol (DAS) and zearalenone by thin-layer chromatography, dermal toxicity test and gas chromatography. Of the total number of peanut samples analysed, 6.9% were positive for the toxic trichothecene(s) (T-2, up to 38.89 mg kg^?1; DAS, up to 2.03 mg kg^?1); 4.8% of total sorghum samples analysed contained T-2 up to 15 mg kg^?1. Zearalenone was not found in any of the samples tested, and no toxins were detected in any of the maize samples. Samples marketed during winter and summer periods were contaminated with the toxins. All the toxin-positive samples except one peanut sample were found in produce stored for more than a week.     

Factors Affecting 1-Octen-3-ol in Mushrooms at Harvest and During Postharvest Storage

Harvesting experiments revealed that immature whole mushrooms with closed veils had higher 1-octen-3-0l levels than more mature whole mushrooms with open veils. The l-octen-3-01 content of the gills was higher in immature mushrooms with closed veils, gradually decreased with maturity as the veil opened, and finally increased after the gills were well exposed. Postharvest experiments demonstrated that storage temperature influenced the activity of lipoxygenase-hydroperoxide lyase, but no differences in 1-octen-3-01 content were observed. Enzyme activity as well as 1-octen-3-01 content decreased during storage. Addition of calcium chloride to irrigation water, employed to improve quality and shelf life of fresh mushrooms, increased the amount of l-octen-3-01 immediately after harvest.     

Application of enzymatically gelled chitosan solutions to water‐resistant adhesives

An investigation was undertaken on the application of dilute chitosan solutions gelled by tyrosinase‐catalyzed reaction with 3,4‐dihydroxyphenethylamine (dopamine). The tyrosinase‐catalyzed reaction with dopamine conferred water‐resistant adhesive properties to the semidilute chitosan solutions. The viscosity of the chitosan solutions increased highly by the tyrosinase‐catalyzed reaction and the subsequent reactions between o‐quinone compounds and chitosan. These highly viscous, gel‐like modified chitosan materials were allowed to spread onto the surfaces of the glass slides, which were tightly lapped together and held them in water. Tensile shear adhesive strength of over 400 kPa was observed for the modified chitosan samples. The increase in the amino group concentration of the chitosan solutions and the molecular mass of the chitosan used effectively led to the increase in adhesive strength of the glass slides. In addition, in the case where the chitosan solution was gelled by the enzymatic reaction with dopamine in the presence of poly(ethylene glycol), adhesive strength sharply increased at shorter reaction times concomitantly with the increase in the viscosity of the chitosan solutions because the tyrosinase activity effectively was retained by poly(ethylene glycol). © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1818–1827, 2007     

Toxicity of nitro compounds fromLotus pedunculatus to grass grub (Costelytra zealandica) (Coleoptera: Scarabaeidae)

Crude extracts of root of the forage legumesLotus pedunculatus andCoronilla varia (crownvetch) were toxic when administered orally to 3rd instarCostelytra zealandica larvae. A group of 3-nitropropanoyl-d-glucopyranoses was isolated from active fractions of the crude extracts. These toxins, some of which were already known fromC. varia, have not previously been reported fromL. pedunculatus. The compounds were present in root tissue of this species at a concentration of about 1% dry weight. They include the triester karakin and the diesters coronarian and cibarian, all of which were toxic to larvae ofC. zealandica at levels which could account fully for the activity of the crude extracts.     

Olfactory aposematism

Visual and acoustic cues may serve as aposematic signals that warn predators of poisonous foods. Olfactory aposematism, the use of innocuous odors as warning signals for toxic foods, is another possible means of alerting an animal that a potential food item is unpalatable. Although it has been suggested that olfactory aposematism might be the principle mode of warning utilized by plants in their defense against herbivores, experimental evidence is lacking. This study demonstrates that the opossum,Didelphis virginiana, can utilize an innocuous volatile compound found naturally in a mushroom as a warning signal for a delayed illness caused by mushroom toxin. This supports the contention that characteristic odors of toxic plants may serve a warning function, protecting herbivores from being poisoned and plants from being consumed.     

心肌细胞电位传感器在海洋生物毒素检测中的研究

目前海洋毒素对人类健康的威胁越加严重,尤其是麻痹性毒素。提出了一种基于细胞电位传感器检测贝类的生物毒性的新方法,采用心肌细胞与微电子加工技术的微阵列芯片（MEA）相结合,构建了新型的心肌细胞电位传感器。通过心肌细胞与MEA芯片的紧密耦合,实现了实时监测心肌细胞电位的变化,输出稳定和一致性好的胞外场电位信号。通过检测海洋中危害较大的石房蛤麻痹性毒素（STX）,分析细胞的信号特征参数,实验结果表明,STX毒素对心肌细胞的电生理活动有明显的抑制作用,对脉冲幅值和脉冲频率有明显的浓度依赖性抑制作用。常规标准的生物毒性检测方法小鼠生物法的检出限为40 g/100 g,而心肌细胞电位传感器可检测的下限为1.004 ng/mL,检测范围为25 nmol/L~1600 nmol/L,通过对比表明该方法具有较好的检出限且检测方法相对简单,易于规范化和标准化。通过进一步的完善,该方法在海洋毒素的快速检测应用方面具有良好的发展前景。     

碳源和氮源对平菇（PH06）菌丝生长的影响

试验选取四种碳源及每种碳源七种不同浓度,同时选取六种氮源每种氮源七种不同浓度,进行对比试验从中选出适合平菇（PH06）菌丝生长的最佳碳源及氮源.实验证明,固体培养基中平菇（PH06）菌丝生长的最佳碳源是浓度为1.5%可溶性淀粉.最佳氮源是浓度为0.7%蛋白胨和浓度为0.7%酵母粉,最佳碳氮源组合是浓度为0.5%的麦芽糖与浓度为0.7%的酵母粉.