In vivo toxicity study of dialkyl disulphides

As a result of the industrial purification of hydrocarbons from mercaptans, tens of thousands of tons of dialkyl disulphides and their mixtures, the toxicity and hazard of which has not been fully understood, are accumulated annually. The exposure standards have been developed only for dimethyl disulphide. The study was aimed to define toxicometry parameters for diethyl disulphide, disulphide oil, and the mixture of dialkyl disulphides. Toxicology studies involving male outbred rats made it possible to define the median lethal doses and concentrations: diethyl disulphide — after intragastric injection DL50 = 1575 mg/kg, after the 4-hour inhalation exposure CL50 = 18,700 mg/m3, after intraperitoneal injection DL50 = 1134 mg/kg, and after skin application DL50 ˃ 2500 mg/kg; mixture of dialkyl disulphides — after intragastric injection DL50 = 428 mg/kg, after the 4-hour inhalation exposure CL50 = 4510 mg/m3, after intraperitoneal injection DL50 = 212 mg/kg, and after skin application DL50 ˃ 2500 mg/kg; disulphide oil — after intragastric injection DL50 = 448 mg/kg, after the 4-hour inhalation exposure CL50 = 4534 mg/m3, after intraperitoneal injection DL50 = 156 mg/kg, and after skin application DL50 ˃ 2500 mg/kg. The hazard assessment for dialkyl disulphides and their mixtures was performed.

Pulsed Electric Field (PEF) Processing of Chilled and Frozen-Thawed Lamb Meat Cuts: Relationships between Sensory Characteristics and Chemical Composition of Meat

The effect of PEF processing and chilled storage on the volatile composition and sensory properties of chilled and frozen lamb cuts was investigated in this study. Results showed that PEF-treated chilled and frozen lamb cuts varied in temporal flavour attributes with storage. Storage for 7 days resulted in oxidized flavour, while PEF treatments for all chilled and frozen cuts were associated with browned and livery flavour attributes. Partial least squares regression (PLSR) was applied to determine the predictive relationships between the volatile composition, fatty acid and amino acid profiles, and sensory responses for PEF treated lamb cuts. The results showed that some volatile compounds (2-nonanone, 2-pentylfuran, pyrrole, methyl pyrazine, 2-ethyl-3-methyl pyrazine, and thiophene) correlated well with the meaty and juicy flavour of PEF treated frozen lamb cuts. In PEF treated chilled lamb cuts, meaty and juicy flavours were associated with the presence of fatty acids (C18:0, SFA, 20:5(n-3), and n-3). In contrast, livery and browned perception of both PEF processed chilled and frozen lamb cuts were associated with the presence of amino acids (threonine, phenylalanine, isoleucine, tyrosine, and methionine), and some volatile compounds (heptanal, 2-ethylfuran, pyridine, dimethyl disulphide, dimethyl trisulphide, and 3,5-diethyl-2-methyl pyrazine). Overall, these results imply that careful consideration of type of meat cuts, PEF pre-treatment, and storage are important when subjecting lamb meat to PEF processing.

The Use of Concentrates Rich in Orange By-Products in Goat Feed and Its Effects on Physico-Chemical, Textural, Fatty Acids, Volatile Compounds and Sensory Characteristics of the Meat of Suckling Kids

We analysed how replacing cereal concentrates with dehydrated orange pulp (DOP) in the diet of mother goats affects the meat quality of suckling kids. Three experimental diets for mother goats were designed. The DOP-0 diet contained commercial concentrates and alfalfa hay. In the DOP-40 and DOP-80 diets, 40% and 80% (respectively) of the cereal in the concentrate was replaced with pellets of DOP (the alfalfa hay component was unchanged). We evaluated the chemical composition, texture, water holding capacity, colour, fatty acids (FAs) profile, volatile compounds, and sensorial appraisal of the meat from 30 male suckling kids (cold carcass weight 4.74 kg, 4.82 kg, and 4.65 kg for DOP-0, DOP-40, and DOP-80, respectively) of the Payoya breed (n = 10 for each diet). Meat from kids in the DOP-40 and DOP-80 groups exhibited characteristics favourable for human health, including the meat’s thrombogenicity index, PUFA/SFA ratio (0.60 index), and n-6 PUFA/n-3 PUFA ratio (approximately 7.50). The meat also exhibited reduced MUFA content (around 460 mg/100 g fresh meat). An increase in ethyl furan, dimethyl disulphide and heptane was observed in grilled meat from goats that were fed using DOP. The inclusion of DOP in goat feed improved consumers’ sensory appreciation of the kid’s meat.

Method Validation and Dissipation Behaviour of Dimethyl Disulphide (DMDS) in Cucumber and Soil by Gas Chromatography-Tandem Mass Spectrometry

In this study, a useful analytical method was developed and validated for measuring the residues of dimethyl disulphide (DMDS) in cucumbers and soil by gas chromatography-tandem mass spectrometry (GC-MS/MS). The dissipation dynamics and residual levels of DMDS in cucumber and soil were also studied in Shandong, Jilin, and Hebei provinces by using this method. Dichloromethane was selected and used as the extraction solvent to extract the target pesticide from the soil and cucumber samples. The soil and cucumber samples were cleaned up by the combination of multiwalled carbon nanotubes (MWCNT) and biochar. The average recoveries of the DMDS in cucumbers and soil were in the range of 84–101.5%, with relative standard deviations (RSD) of 0.7–4.9%, when they spiked at 0.05, 0.5, and 5 mg/kg DMDS respectively. The limit of quantification (LOQ) of this method was 0.05 mg/kg. First-order and second-order kinetic equations were used to fit dissipation data. Results show that the half-lives of DMDS in the soil at Shandong, Jilin, and Hebei were 1.63–4.47 days, 1.96–6.49 days, and 1.35–2.51 days, respectively. The final residues of DMDS were less than 0.05 mg/kg in cucumbers and 0.36 mg/kg in the soil. The dissipation rates of DMDS in different soils were different. The method provides a basis for the risk assessment of DMDS in cucumber and soil.

Effect of Support on the Performance of CoMoRe Catalyst in Thiophene and Benzothiophene Hydrodesulfurization

This work is aimed at selection of a suitable support for CoMoRe catalyst in hydrodesulfurization (HDS) of thiophenes. g-Al2O3 and g-Al2O3-HMS were used as a support for CoMoRe catalyst with 4%Co, 8%Mo and 0.5%Re loading. The metal loading was incorporated by using the pore volume impregnation method, employing aqueous solutions of cobalt (II) nitrate, ammonium molibdate and rhenium (VII) oxide. The catalysts were sulfided with dimethyl disulphide at 250 �C for 10 h and finally tested in the HDS reaction of thiophene and benzothiophene in different temperature and pressure conditions. The catalysts were characterized by determining the adsorption isotherms, the pore size distribution and the acid strengt, FTIR, XRD and S EM. T he catalyst supported on g - Al2O3 displayed higher activity than catalyst supported on g-Al2O3-HMS. The results suggest that activity is favoured by the suitable textural and acidic properties of the support.

Suppressive efficacy of volatile compounds produced byBacillus mycoideson damping-off pathogens of cabbage seedlings

Rhizoctonia solaniKühn andPythium aphanidermatumEdson cause cabbage seedling damping-off, resulting in severe yield losses. The current study demonstrates the production of toxic volatile organic compounds (VOCs) by two strains ofBacillus mycoidesand the evaluation of a potential use ofB.mycoidesas a biocontrol agent to control cabbage damping-off. Two VOCs, dimethyl disulphide and ammonia, were found to reduce radial growth, cause hyphal deformation and result in organelle degeneration in bothR. solaniandP. aphanidermatum. Pathogen hyphae, after being exposed to VOCs, showed poor rigidity, shrinkage, curling and swelling. The amount of VOCs produced byB. mycoidesand the antagonistic activity against plant pathogens varied, depending on the type of medium used to culture bacteria. Application ofB.mycoidescell suspensions to cultivation medium promotes growth of five different plant species tested. Experiments conducted in greenhouses revealed thatB. mycoidesdid not reduce damping-off incidence caused byR.solani. However,B. mycoidesreduced damping-off incidence induced byP. aphanidermatumby as much as 45% on cabbage seedlings. The results provide valuable information on the feasibility of utilizingB. mycoidesas a biocontrol agent in controlling cabbage damping-off.

The Study of Natural Saponification Processes in Preservation of Human Corpses

The natural course of evolution of the human body after death includes autolysis, putrefaction and skeletonization. Under specific environmental conditions, the body may bypass this natural path, leading to preservation, such as saponification (adipocere), lignification, mummification or refrigeration, comprising the entire body or being limited only to some parts of it. All these preservation processes have a chemical substrate, and the identification of their components may be useful in many forensic circumstances, such as clandestine activity and identification of victims in mass disasters, when pentanoic, butanoic, hexanoic acid, butanoic acid-butyl ester, hexanoic acid-ethyl ester, indole, dimethyl disulphide may be used to train human remains detection dogs. The authors present the case of a 73 years old woman who was found dead in a sewage collection basin 4 months after her disappearance in July. The autopsy revealed a mixture of cadaveric processes, some parts being disintegrated, with putrefaction and skeletonization, while other parts were preserved by saponification: areas of adipocere were found on the neck, thorax and the anterior part of the abdomen. In some instances the saponification of the corpses makes identification possible and preserves violence marks, but the combination with putrefaction burdens these goals. The identification in this case was possible using the teeth formula, keeping in mind that tooth and bones are the most resistant to putrefaction. Even though saponification makes difficult the estimation of postmortem interval, investigations of its chemical composition may be useful in this direction, as the epicoprostanol-cholesterol ratio proved to increase with the increasing of postmortem interval.

Cancer sniffer dogs: how can we translate this peculiarity in laboratory medicine? Results of a pilot study on gastrointestinal cancers

Background:Identification of cancer biomarkers to allow early diagnosis is an urgent need for many types of tumors, whose prognosis strongly depends on the stage of the disease. Canine olfactory testing for detecting cancer is an emerging field of investigation. As an alternative, here we propose to use GC-Olfactometry (GC/O), which enables the speeding up of targeted biomarker identification and analysis. A pilot study was conducted in order to determine odor-active compounds in urine that discriminate patients with gastrointestinal cancers from control samples (healthy people).Methods:Headspace solid phase microextraction (HS-SPME)-GC/MS and GC-olfactometry (GC/O) analysis were performed on urine samples obtained from gastrointestinal cancer patients and healthy controls.Results:In total, 91 key odor-active compounds were found in the urine samples. Although no odor-active biomarkers present were found in cancer carrier’s urine, significant differences were discovered in the odor activities of 11 compounds in the urine of healthy and diseased people. Seven of above mentioned compounds were identified: thiophene, 2-methoxythiophene, dimethyl disulphide, 3-methyl-2-pentanone, 4-(or 5-)methyl-3-hexanone, 4-ethyl guaiacol and phenylacetic acid. The other four compounds remained unknown.Conclusions:GC/O has a big potential to identify compounds not detectable using untargeted GC/MS approach. This paves the way for further research aimed at improving and validating the performance of this technique so that the identified cancer-associated compounds may be introduced as biomarkers in clinical practice to support early cancer diagnosis.