Sulphur tracer experiments in laboratory animals using 34S-labelled yeast

Area of Science:

• Biochemistry
• Animal Nutrition
• Isotope Tracing

Background:

• Sulfur is an essential element for life, crucial for amino acids and various biomolecules.
• Accurate tracking of sulfur metabolism in vivo is vital for understanding nutritional requirements and metabolic disorders.
• Developing reliable sulfur tracers is key for advancing metabolic research in laboratory animals.

Purpose of the Study:

• To evaluate the efficacy of sulfur-34 (34S)-labelled yeast as a tracer for sulfur metabolic studies in laboratory animals.
• To establish optimal conditions for preparing 34S-labelled yeast.
• To assess the suitability of 34S-labelled yeast as a sulfur source in in vitro digestion models and in vivo animal studies.

Main Methods:

• Culture optimization for 34S-labelled yeast production.
• In vitro gastrointestinal digestion assays combined with gel electrophoresis and HPLC-ICP-MS.
• In vivo kinetic studies in Wistar rats involving oral administration of 34S-labelled yeast.
• Inductively coupled plasma mass spectrometry (ICP-MS) for isotopic analysis of sulfur in tissues, urine, and feces.

Main Results:

• In vitro digestion confirmed labeled methionine, cysteine, and low molecular weight sulfur compounds as major components.
• In vivo studies showed measurable 34S isotopic enrichment in all analyzed tissues, urine, and feces.
• HPLC-ICP-MS analysis of urine revealed differential isotope enrichment in specific sulfur-containing biomolecules.

Conclusions:

• 34S-labelled yeast is a suitable and effective tool for sulfur metabolic tracer experiments in laboratory animals.
• The study successfully demonstrated the tracking of sulfur distribution and enrichment in vivo.
• Further investigation into urine metabolite analysis shows potential for detailed metabolic pathway elucidation.