scholarly journals Non-enzymatic Transformation of Aflatoxin B1 by Pseudomonas geniculata m29

2021 ◽  
Vol 12 ◽  
Author(s):  
Yuanyuan Yao ◽  
Xian Shu ◽  
Dongdong Wang ◽  
Wenjie Kan ◽  
Pengfei Su ◽  
...  
Keyword(s):  
Chronic Toxicity ◽  
High Efficiency ◽  
Animal Health ◽  
Molecular Formula ◽  
Optimum Temperature ◽  
Transformation Mechanism ◽  
Enzymatic Transformation ◽  
Transformation Ratio ◽  
Transforming Activity ◽  
Aflatoxin B

Aflatoxin B1 (AFB1) is the most harmful mycotoxin produced by filamentous fungi and presents a serious threat to human and animal health. Therefore, it is essential to protect humans and animals from AFB1-induced acute and chronic toxicity. In this study, Pseudomonas strain m29 having a high efficiency of AFB1 transformation was isolated from soil. The transformation ratio by m29 was more than 97% within 24 h, and the optimum temperature for transformation was 37°C. Moreover, the AFB1 transforming activity was mainly attributed to the cell-free supernatant of strain m29. The metabolite that plays a crucial role in AFB1 transformation is likely 1,2-dimethylhydrazine or 1,1-dimethylhydrazine, as identified by GC-MS and LC-MS analysis. AFB1 was transformed into a product with molecular formula C17H14O7. To the best of our knowledge, this is the first study of non-enzymatic AFB1 transformation by bacteria. Importantly, this AFB1 transformation mechanism could be universal to various microorganisms.

scholarly journals Parameters and design optimization of the ring piezoelectric ceramic transformer

2015 ◽  
Vol 05 (03) ◽  
pp. 1550022 ◽  
Author(s):  
Jiří Erhart
Keyword(s):  
High Efficiency ◽  
Strong Electric Field ◽  
Resistive Load ◽  
Optimum Load ◽  
Aspect Ratios ◽  
Transformation Ratio ◽  
Ring Segment ◽  
New Type ◽  
Transformation Parameters ◽  
Piezoelectric Ceramic Transformer

Main aim of the presented paper is the theoretical analysis and experimental verification of the transformation parameters for the new type of nonhomogeneously poled ring transformer. The input part is poled in the thickness direction and output part in the radial direction. Two transformer geometries are studied — the input part is at inner ring segment, or it is at the outer ring segment. The optimum electrode size aspect ratios have been found experimentally as [Formula: see text] for the ring with aspect ratio [Formula: see text]. The fundamental as well as higher overtone resonances were studied for the transformation ratio, the optimum resistive load, efficiency and no-load transformation ratio. Higher overtones have better transformation parameters compared to the fundamental resonance. The new type ring transformer exhibits very high transformation ratios up to 200 under no-load and up to 13.4 under a high efficiency of 97% at the optimum load conditions of 10 [Formula: see text]. Strong electric field gradient at the output circuit is applicable for the electrical discharge generation.

scholarly journals Aflatoxin contamination in Tanzania: quantifying the problem in maize and groundnuts from rural households

2021 ◽  
pp. 1-12
Author(s):  
S.B. Boni ◽  
F. Beed ◽  
M.E. Kimanya ◽  
E. Koyano ◽  
O. Mponda ◽  
...  
Keyword(s):  
Body Weight ◽  
High Performance ◽  
Animal Health ◽  
Daily Intake ◽  
Aflatoxin Contamination ◽  
Aflatoxin Level ◽  
Awareness Campaigns ◽  
Food And Feed ◽  
The Mean ◽  
Aflatoxin B

Aflatoxins are toxic and carcinogenic secondary metabolites, produced by Aspergillus flavus and Aspergillus parasiticus, which contaminate food and feed and threaten human and animal health. To assess the prevalence of aflatoxins in Tanzania, 180 groundnut and 200 maize samples were collected from 9 and 10 districts, respectively. Aflatoxin contamination was quantified using high performance liquid chromatography. Aflatoxins were detected in samples collected from all districts and prevalence ranged from 92 to 100% for groundnuts and 10 to 80% for maize. The mean aflatoxin level for groundnuts was 6.37 μg/kg and the highly contaminated sample had 40.31 μg/kg. For maize, the mean aflatoxin level was 12.47 μg/kg and the highly contaminated sample had 162.40 μg/kg. The estimated average probable daily intake (APDI) of aflatoxin B1 (AFB1) from groundnuts consumption was 1.88 ng/kg body weight/day, while for maize, it ranged between 151.98-272.89 ng/kg body weight/day. The APDI for both groundnut and maize exceeded the provisional maximum tolerable daily intake (PMTDI) of AFB1 for adults (1 ng/kg body weight/day), bringing about health concerns for populations in Tanzania. Another alarming finding was that 75% of the farmers who provided samples for analysis were not aware of aflatoxins or the negative health impacts from consuming contaminated products. Results reported in this paper show that aflatoxin contaminated staple crops are widely distributed in Tanzania and that the risk of human exposure is high due to diet preferences. Awareness campaigns are required to inform and protect farmers and consumers.

Multi-mycotoxin profiling in maize reveals prevalence of Fusarium mycotoxins in South and West Ethiopia

2021 ◽  
pp. 1-12
Author(s):  
A. Mesfin ◽  
K. Tesfamariam ◽  
T. Belachew ◽  
S. De Saeger ◽  
C. Lachat ◽  
...  
Keyword(s):  
Animal Feed ◽  
Animal Health ◽  
Special Focus ◽  
Fusarium Mycotoxins ◽  
Ecological Zones ◽  
Mycotoxin Contamination ◽  
Protective Strategies ◽  
Contamination Levels ◽  
Aflatoxin B ◽  
Study Participants

Multi-mycotoxin exposure data are missing to guide risk assessment and legislation in Ethiopia. This study therefore aimed to determine mycotoxin contamination levels in maize samples from 176 randomly selected household storages in three agro ecological zones of South (Sidama zone) and West (Jimma zone) Ethiopia, and to examine the post-harvest practices and household processing. Liquid chromatography coupled to tandem mass spectrometry was used to quantify 23 mycotoxins. The majority of the households regularly consumed maize (more than once per day). More (77%) samples in Sidama were contaminated with Fusarium mycotoxins deoxynivalenol than in Jimma (29%) (P<0.001); Similar distributions of fumonisin B1 (19%), fumonisin B2 (19%) and fumonisin B3 (12%, Sidama vs 13%, Jimma) contamination were observed (P>0.05). In Sidama, only one sample was contaminated with the Aspergillus mycotoxin aflatoxin B2 and another sample with aflatoxin B1. From all samples, 40% were contaminated with 3-5 types of Fusarium mycotoxins and only 4% of the samples were contaminated with 6-8 types of mycotoxins. After the harvested maize was dried on the field, the majority of respondents in Jimma reported that they removed the maize within one day, which was less practiced in Sidama. The majority of households in Sidama, and some in Jimma, reported that they dried maize before storage, mainly using the sun. Close to two third of the study participants in the two zones reported that they applied the chemical dichloro-diphenyl-trichloroethane (DDT) during maize storage. All households in both zones reported that they sorted visible mouldy maize grains before preparation of maize flour while most of them kept the mouldy maize for animal feed. Protective strategies of Fusarium mycotoxin contamination, with special focus on deoxynivalenol and zearalenone, should be well promoted in the study areas as they are possible human and animal health threats.

scholarly journals Design Consideration for High Step-Up Nonisolated Multicellular dc-dc Converter for PV Micro Converters

2018 ◽  
Vol 2018 ◽  
pp. 1-16 ◽  
Author(s):  
Yusuke Hayashi ◽  
Yoshikatsu Matsugaki ◽  
Tamotsu Ninomiya
Keyword(s):  
High Efficiency ◽  
Magnetic Coupling ◽  
Duty Ratio ◽  
Design Consideration ◽  
Low Carbon ◽  
Semiconductor Switches ◽  
High Frequency Transformer ◽  
Transformation Ratio ◽  
Converter Design ◽  
Laboratory Prototype

High step-up nonisolated multicellular dc-dc converter has been newly proposed for PV microconverters. The multicellular converter consists of the nonisolated step-up cell converters using bidirectional semiconductor switches, and these cell converters are connected in Input Parallel Output Series (IPOS). The voltage transformation ratio of the step-up converter is N/(1-D) in case all the transistors in N cell converters are operated at the duty ratio of D. The proposed multicellular dc-dc converter also accomplishes high efficiency because of no magnetic coupling such as the high frequency transformer and the coupled inductor. Laboratory prototype has been fabricated to show the feasibility of the proposed converter. Design consideration for the 20 V–40 V to 384 V, 240 W nonisolated multicellular dc-dc converter has been also conducted, and the potential to achieve the efficiency of 98% has been shown. The proposed multicellular converter contributes to realizing the environmentally aware data centers for future low carbon society.

Safety of low and high cost dry feed intended for dogs in Brazil concerning fumonisins, zearalenone and aflatoxins

2017 ◽  
Vol 10 (3) ◽  
pp. 273-283 ◽  
Author(s):  
E.M.K. Teixeira ◽  
M.S. Frehse ◽  
R.L. Freire ◽  
M.A. Ono ◽  
J.G. Bordini ◽  
...  
Keyword(s):  
Low Cost ◽  
Animal Health ◽  
Daily Intake ◽  
Estimated Daily Intake ◽  
Commercial Feed ◽  
Negative Effect ◽  
Contamination Levels ◽  
And Performance ◽  
Aflatoxin B ◽  
Feed Samples

The Brazilian pet sector exportation has been growing at an impressive rate lately. Considering the intense globalisation, pet food may be commercialised worldwide and the issue concerning safety of dry dog feed has become a topic of widespread international interest. Therefore, the objectives of this study were to evaluate the safety of low and high cost dry feed and the degree of exposure of dogs to mycotoxins through naturally contaminated feed in Brazil. In addition, the safe pet dietary level (SPDL) was calculated. Fumonisins, zearalenone (ZEA) and aflatoxins were analysed in three feed types intended for dogs (n=87), provided by pet owners. Mean fumonisin levels were 272 µg/kg (Standard), 78.2 µg/kg (Premium), and 186 µg/kg (Super Premium) while ZEA mean levels were 52.6 µg/kg (Standard), 10.6 µg/kg (Premium) and 17.5 µg/kg (Super Premium). Mean total aflatoxin levels (aflatoxin B1 + B2 + G1 + G2) in Standard, Premium and Super Premium feed were 1.29 µg/kg, 0.49 µg/kg and 0.53 µg/kg, respectively. The estimated daily intake (EDI) values for fumonisin B1 were 1.41 (Standard), 1.60 (Premium) and 0.93 µg/kg body weight (BW)/day (Super Premium feed), whereas for ZEA they were 0.54 (Standard), 0.37 (Premium) and 0.42 µg/kg BW/day (Super Premium feed). SPDL for fumonisins and ZEA was 2,000 and 375 µg/kg feed, respectively. EDI values for aflatoxin B1 were 13.0 (Standard), 14.0 (Premium) and 11.0 ng/kg BW/day (Super Premium feed). Although the feed samples intended for dogs in Brazil were often contaminated with aflatoxins, fumonisins and ZEA, the estimated daily intake values were low, even for the low cost formulations. However, it cannot be excluded that some of the feed samples could have a negative effect on animal health and performance considering feeding a monodiet of commercial feed, low multi-mycotoxin contamination levels and interactions between mycotoxins.

scholarly journals Effects of 462 nm Light-Emitting Diode on the Inactivation of Escherichia coli and a Multidrug-Resistant by Tetracycline Photoreaction

2018 ◽  
Vol 7 (9) ◽  
pp. 278 ◽  
Author(s):  
Shiuh-Tsuen Huang ◽  
Chun-Yi Wu ◽  
Nan‐Yao Lee ◽  
Chien-Wei Cheng ◽  
Meei-Ju Yang ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Blue Light ◽  
High Efficiency ◽  
Light Emitting Diode ◽  
Phosphate Buffer Solution ◽  
Multidrug Resistant ◽  
Molecular Formula ◽  
Light Illumination ◽  
Light Emitting ◽  
E Coli

The adaptability of bacterial resistance to antibiotics contributes to its high efficiency during evolution. Tetracycline (TC) is a broad-spectrum antimicrobial agent. Chromatographic analyses and mass spectrometry were used to study the effects of the light illumination of a 462 nm light-emitting diode (LED) on the conformational changes of TC in a phosphate buffer solution (PBS, pH 7.8). Especially, the inactivation of superoxide anion radicals (O2•−) and Escherichia coli (E. coli), including that of a multidrug-resistant E. coli (MDR E. coli), were investigated during the photolysis of TC. A photolysis product of TC (PPT) was generated in an alkaline solution after the illumination of a blue light. The mass spectra of PPT had characteristic ion signals in m/z 459, 445, and 249.1 Da. The PPT has the molecular formula of C22H22N2O9, and the exact mass is 458.44 g/mol. The inactivation of MDR E. coli is not significant with TC treatment. The drug-resistant ability of MDR E. coli has a less significant effect on PPT, and the changed conformation of TC retained the inactivation ability of MDR E. coli upon blue light photoreaction. With TC, illuminated by a blue light in a pH 7.8 PBS, O2•− was generated from TC photolysis, which enhanced the inactivation of E. coli and MDR E. coli. A 96.6% inactivation rate of MDR E. coli was reached with TC under 2.0 mW/cm2 blue light illumination at 25 ± 3 °C for 120 min, and the effects of the TC-treated photoreaction on MDR E. coli viability repressed the growth of MDR E. coli by 4 to 5 logs. The present study of the blue light photoreaction of TC offers a new approach to the inactivation of MDR E. coli.

Varietal differences in accumulation of aflatoxin B1 in Indian rice cultivars

2010 ◽  
Vol 3 (3) ◽  
pp. 251-256 ◽  
Author(s):  
K. Reddy ◽  
C. Reddy ◽  
B. Salleh
Keyword(s):  
Animal Health ◽  
Rice Paddy ◽  
Storage Conditions ◽  
Basmati Rice ◽  
Total Phenolic ◽  
Human Consumption ◽  
Rice Cultivars ◽  
Varietal Differences ◽  
Aflatoxin B ◽  
Storage Structures

Rice (paddy) seeds are known to be colonised by Aspergillus flavus in the field or under storage conditions and contaminated with aflatoxins which have impact on human and animal health. In this study, we investigated the varietal differences in 30 Indian healthy rice cultivars used for human consumption (15 normal and 15 basmati) for accumulation of aflatoxin B1 (AFB1) after inoculation with aflatoxin-producing A. flavus (DRAf 009). Significant varietal differences in AFB1 accumulation were observed in normal and basmati rice cultivars. Comparatively, the accumulation of AFB1 is higher in normal cultivars, ranging from 3-628 µg/kg, than in basmati cultivars, ranging from 0.2-7.2 µg/kg. The highest accumulation of AFB1 in normal cultivars was observed in PR 106 (628 µg/kg) and the lowest in IR 64 (3 µg/kg). In basmati rice cultivars, the highest accumulation of AFB1 was observed in Ranbir basmati (7.2 µg/kg) and the lowest in Vasumati (0.2 µg/kg). All these cultivars were evaluated for their total phenolic content (TPC) in rice bran using the Folin-Ciocalteau method. The results indicated that the TPC of normal and basmati cultivars was in the range of 1.96-2.45 and 2.13-2.65 mg gallic acid equivalent (mg/g of bran), respectively. This study may be used as a basis to develop A. flavus resistant rice cultivars and proper storage structures to produce aflatoxin-free rice. This is the first report on the evaluation of various rice cultivars for accumulation of AFB1 after inoculation with A. flavus.

Growth and aflatoxin production of an Italian strain of Aspergillus flavus: influence of ecological factors and nutritional substrates

2011 ◽  
Vol 4 (4) ◽  
pp. 425-432 ◽  
Author(s):  
P. Giorni ◽  
N. Magan ◽  
A. Pietri ◽  
P. Battilani
Keyword(s):  
Predictive Model ◽  
Aspergillus Flavus ◽  
Growth Rates ◽  
Fungal Growth ◽  
Ecological Factors ◽  
Quantitative Relationship ◽  
Aflatoxin Production ◽  
Optimum Temperature ◽  
Ripening Stages ◽  
Aflatoxin B

The aim of this study was to define quantitative relationships between temperature and water activity (aw), fungal growth and aflatoxin B1 (AFB1) production. A strain of Aspergillus flavus isolated from maize in north Italy, and previously tested and found positive for AFB1 production, was used for these experiments. The optimum temperature for AFB1 production was at 25 °C, slightly lower with respect to results obtained in other countries. 0.83 aw was the limit for growth of this strain of A. flavus after 60 days incubation at the optimum temperature. The solutes used to modify aw, glycerol and NaCl, influenced both growth and secondary metabolite production. Media modified with glycerol resulted in more AFB1 production when compared to the non-ionic solute NaCl added media. Maize based media, prepared with flour obtained from kernels at different ripening stages, only slightly influenced growth rates of A. flavus. The quantitative relationship obtained between fungal growth and AFB1 production in diverse temperature and aw levels were used to develop a valid predictive model for A. flavus presence and AFB1 production in the field.

scholarly journals Mycotoxins and oxidative stress: where are we?

2018 ◽  
Vol 11 (1) ◽  
pp. 113-134 ◽  
Author(s):  
E.O. da Silva ◽  
A.P.F.L. Bracarense ◽  
I.P. Oswald
Keyword(s):  
Oxidative Stress ◽  
Reactive Oxygen Species ◽  
Animal Health ◽  
Protein Damage ◽  
Oxygen Species ◽  
Protective Effects ◽  
Food And Feed ◽  
Plausible Mechanism ◽  
Aflatoxin B ◽  
And Oxidative Stress

Mycotoxins are the most common contaminants of food and feed worldwide and are considered an important risk factor for human and animal health. Oxidative stress occurs in cells when the concentration of reactive oxygen species exceeds the cell’s antioxidant capacity. Oxidative stress causes DNA damage, enhances lipid peroxidation, protein damage and cell death. This review addresses the toxicity of the major mycotoxins, especially aflatoxin B1, deoxynivalenol, nivalenol, T-2 toxin, fumonisin B1, ochratoxin, patulin and zearalenone, in relation to oxidative stress. It summarises the data associated with oxidative stress as a plausible mechanism for mycotoxin-induced toxicity. Given the contamination caused by mycotoxins worldwide, the protective effects of a variety of natural compounds due to their antioxidant capacities have been evaluated. We review data on the ability of vitamins, flavonoids, crocin, curcumin, green tea, lycopene, phytic acid, L-carnitine, melatonin, minerals and mixtures of anti-oxidants to mitigate the toxic effect of mycotoxins associated with oxidative stress.

scholarly journals Organophosphorus and carbamates residues in milk and feedstuff supplied to dairy cattle

2011 ◽  
Vol 31 (7) ◽  
pp. 598-602 ◽  
Author(s):  
Rafael Fagnani ◽  
Vanerli Beloti ◽  
Ana Paula P. Battaglini ◽  
Karen da S. Dunga ◽  
Ronaldo Tamanini
Keyword(s):  
Gas Chromatography ◽  
Dairy Cattle ◽  
Water Samples ◽  
Chronic Toxicity ◽  
Animal Health ◽  
Dairy Farms ◽  
Raw Milk ◽  
Milk Samples ◽  
Feed Samples ◽  
Toxicity Effects

Considering acute and chronic toxicity effects on human and animal health caused by pesticide residues in food, this study aimed to analyze organophosphorate (OP) and carbamate (CB) in feedstuff and water destined for dairy cattle, as well as in the milk produced by these animals, through gas chromatography (GC). In the Agreste region of Pernambuco, Brazil, 30 raw milk samples and all components of the animals' diet were collected from several farms. Out of the 30 milk of milk analyzed, six (20%) were contaminated with OP, five (16.7%) with CB, and one sample with both pesticides. From 48 analyzed feed samples, 15 (31.25%) were contaminated with residues of OP, six (12.50%) with CB, and one sample was contaminated with both pesticides. Out of 16 water samples analyzed, six (37.50%) were contaminated with OP residues, but non with CB. In four dairy farms the pesticides detected in milk were compatible with the active principles found in water and/or foodstuff, suggesting them to be the source of contamination.

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