Rhodanese (thiosulfate:cyanide sulfurtransferase) distribution in the digestive tract of chicken

Dietary resources shape the adaptive changes of cyanide detoxification function in giant panda (Ailuropoda melanoleuca)

The functional adaptive changes in cyanide detoxification in giant panda appear to be response to dietary transition from typical carnivore to herbivorous bear. We tested the absorption of cyanide contained in bamboo/bamboo shoots with a feeding trial in 20 adult giant pandas. We determined total cyanide content in bamboo shoots and giant panda’s feces, levels of urinary thiocyanate and tissue rhodanese activity using color reactions with a spectrophotometer. Rhodanese expression in liver and kidney at transcription and translation levels were measured using real-time RT-PCR and immunohistochemistry, respectively. We compared differences of rhodanese activity and gene expressions among giant panda, rabbit (herbivore) and cat (carnivore), and between newborn and adult giant pandas. Bamboo shoots contained 3.2 mg/kg of cyanide and giant pandas absorbed more than 65% of cyanide. However, approximately 80% of absorbed cyanide was metabolized to less toxic thiocyanate that was discharged in urine. Rhodanese expression and activity in liver and kidney of giant panda were significantly higher than in cat, but lower than in rabbit (all P < 0.05). Levels in adult pandas were higher than that in newborn cub. Phylogenetic analysis of both nucleotide and amino acid sequences of the rhodanese gene supported a closer relationship of giant panda with carnivores than with herbivores.

Noninvasive monitoring of treatment response in a rabbit cyanide toxicity model reveals differences in brain and muscle metabolism

Noninvasive near infrared spectroscopy measurements were performed to monitor cyanide (CN) poisoning and recovery in the brain region and in foreleg muscle simultaneously, and the effects of a novel CN antidote, sulfanegen sodium, on tissue hemoglobin oxygenation changes were compared using a sub-lethal rabbit model. The results demonstrated that the brain region is more susceptible to CN poisoning and slower in endogenous CN detoxification following exposure than peripheral muscles. However, sulfanegen sodium rapidly reversed CN toxicity, with brain region effects reversing more quickly than muscle. In vivo monitoring of multiple organs may provide important clinical information regarding the extent of CN toxicity and subsequent recovery, and facilitate antidote drug development.

Distribution of the enzyme rhodanese in tissues of the cat (Felis catus)

The enzyme rhodanese (EC 2.8.1.1) is an ubiquitous enzyme which is present in all living organisms, from bacteria to man. It is speculated that this enzyme plays a central role in cyanide detoxification. However, its wide tissue distribution suggests this enzyme might perform other functions beside cyanide detoxification. Although the distribution of rhodanese in different tissues of human and domestic animals has been studied, little is known about the pattern of distribution and physiological roles of this enzyme in the cat. The purpose of this investigation was to determine the enzyme levels and compare the distribution of this enzyme in different tissues of the cat. A selection of tissue samples was assayed for rhodanese activity. The protein content of tissue extracts and enzymatic activities were calculated as units per gram tissue and units per milligram protein of the tissue. Results showed that in terms of units per milligram protein of the tissue (specific activity of the enzyme), colon and rectum mucosal layers and testis were the richest sources of the enzyme followed by ovary, mucosal layer of jejunum and liver. With respect to units/gram tissue, liver followed by testis, colon and rectum mucosal layers, ovary and mucosa of jejunum exhibited highest activities. The results of this study will allow one to speculate on the involvement of rhodanese in several biochemical and physiological functions in different tissues and organs of this species.

Involvement of Pseudomonas aeruginosa rhodanese in protection from cyanide toxicity

Cyanide is a serious environmental pollutant and a biocontrol metabolite in plant growth-promoting Pseudomonas species. Here we report on the presence of multiple sulfurtransferases in the cyanogenic bacterium Pseudomonas aeruginosa PAO1 and investigate in detail RhdA, a thiosulfate:cyanide sulfurtransferase (rhodanese) which converts cyanide to less toxic thiocyanate. RhdA is a cytoplasmic enzyme acting as the principal rhodanese in P. aeruginosa. The rhdA gene forms a transcriptional unit with the PA4955 and psd genes and is controlled by two promoters located upstream of PA4955 and rhdA. Both promoters direct constitutive RhdA expression and show similar patterns of activity, involving moderate down-regulation at the stationary phase or in the presence of exogenous cyanide. We previously observed that RhdA overproduction protects Escherichia coli against cyanide toxicity, and here we show that physiological RhdA levels contribute to P. aeruginosa survival under cyanogenic conditions. The growth of a DeltarhdA mutant is impaired under cyanogenic conditions and fully restored upon complementation with rhdA. Wild-type P. aeruginosa outcompetes the DeltarhdA mutant in cyanogenic coculture assays. Hence, RhdA could be regarded as an effector of P. aeruginosa intrinsic resistance to cyanide, insofar as it provides the bacterium with a defense mechanism against endogenous cyanide toxicity, in addition to cyanide-resistant respiration.

Evidence for a functional genetic polymorphism of the human thiosulfate sulfurtransferase (Rhodanese), a cyanide and H2S detoxification enzyme

Rhodanese or thiosulfate sulfurtransferase (TST) is a mitochondrial matrix enzyme that plays roles in cyanide detoxification, the formation of iron-sulfur proteins and the modification of sulfur-containing enzymes. Transsulfuration reaction catalyzed by TST is also involved in H(2)S detoxification. To date, no polymorphism of the human TST gene had been reported. We developed a screening strategy based on a PCR-SSCP method to search for mutations in the 3 exons of TST and their proximal flanking regions. This strategy has been applied to DNA samples from 50 unrelated French individuals of Caucasian origin. Eleven polymorphisms consisting in seven nucleotide substitutions in non-coding regions, two silent mutations and two missense mutations were characterized. The functional consequences of the identified mutations were assessed in vivo by measurement of erythrocyte TST activity and/or in vitro using heterologous expression in Saccharomyces cerevisiae or transient transfection assay in HT29 and Caco-2 cell lines. The P(285)A variant appears to encode a protein with a 50% decrease of in vitro intrinsic clearance compared to the wild-type enzyme. Additionally, the six polymorphisms located upstream the ATG initiation codon are responsible for a significant decrease (ranging from 40% to 73%) in promoter activity of a reporter gene compared to the corresponding wild-type sequence. This work constitutes the first report of the existence of a functional genetic polymorphism affecting TST activity and should be of great help to investigate certain disorders for which impairment of CN(-) or H(2)S detoxification have been suggested to be involved.

Distribution of rhodanese in tissues of goat (Capra hircus)

Rhodanese (thiosulfate: cyanide sulfurtransferase, EC. 2.8.1.1) is a ubiquitous enzyme present in all living organisms, from bacteria to humans and plays a central role in cyanide detoxification. The purpose of this investigation is to determine and compare rhodanese activity in different tissues of adult male and female goats (Capra hircus). The results showed that the specific activity of rhodanese in different tissues was significantly different (P<0.05). The highest activity of rhodanese was in epithelium of rumen, followed by epithelia of reticulum and omasum and liver. No significant difference was observed when tissues of male and female goats were compared. The lowest specific activity of rhodanese was observed in spleen, urinary bladder, lymph node, ovary, skeletal muscle and pyloric muscle of abomasum. The results of this study may indicate the involvement of rhodanese in cyanide detoxification in goat tissues that have greater potential to be exposed to higher levels of cyanide.

Rhodanese distribution in porcine (Sus scrofa) tissues

The enzyme rhodanese (thiosulfate/cyanide sulfurtransferase) is an ubiquitous enzyme and its activity is present in all living organisms from bacteria to man. Evidence has been accumulated to indicate that this enzyme plays a central role in cyanide detoxification. A comparison was made of rhodanese activity in different tissues of young male and adult male and female pig (Sus scrofa). The highest activity of rhodanese was in liver and kidney cortex of all animals. Among the remaining tissues examined, the kidney medulla and the stomach epithelium tended to have higher levels than other tissues, although this was not significant (P>0.05). The rhodanese activity of heart ventricle tissue of 6-month-old male animals was higher than 7-week-old male animals (P<0.05), and 6-month-old male animals had higher rhodanese activity in lung tissue, compared to 6-month-old female pigs (P<0.05). Medulla and spleen of younger male animals exhibited higher levels of activity (P<0.10) compared to older male pigs. The results of this study may indicate the involvement of rhodanese in cyanide detoxification in pig tissues, which have greater potential to be exposed to higher levels of cyanide.

Distribution of rhodanese in different parts of the urogenital systems of sheep at pre- and post-natal stages

The enzyme rhodanese (thiosulfate:cyanide sulfurtransferase) is a ubiquitous enzyme present in all living organisms, from bacteria to humans and plays a central role in cyanide detoxification. The purpose of this investigation is to determine and compare rhodanese activity in different parts of urogenital systems of male and female sheep fetuses at 2.5, 3, 3.5, 4, 4.5, and 5 months of age. The highest activity of rhodanese in male fetus was in kidney cortex, followed by medulla of the kidney. No significant difference was observed in other organs. In female fetus, the highest activity was in kidney cortex followed by oviduct and medulla of kidney. The enzyme activity of tissues increased with age. There was no significant difference (P > 0.05) between male and female fetuses in levels of rhodanese activity of different tissues except in urinary bladder at 2.5 and 3 months and in urethra at 4.5 months of age. The results of this study might indicate the involvement of rhodanese in cyanide detoxification in tissues which are more exposed to cyanide. On the other hand, rhodanese might perform other functions which are specific in these tissues.

Rhodanese (thiosulfate: cyanide sulfurtransferase) in the digestive tract of chicken at different stages of development

This study was undertaken to investigate the relationships between stage of embryonic development and early posthatch growth and the level of rhodanese (thiosulfate:cyanide sulfurtransferase) activity in different regions of the digestive tract and liver of chickens. The embryos were studied at 14, 17, and 20 d and chickens were 1, 2, and 3 wk old. All tissues studied contained rhodanese. The highest specific activity of rhodanese was present in the liver followed by the proventriculus (P < 0.05). The lowest level was in the esophagus. The level of rhodanese was found to increase with age in the proventriculus and duodenum. The highest rhodanese activity in 3-wk-old chickens was in the proventriculus followed by the liver. These results are discussed in terms of the role of different sections of the digestive tract of the chicken in cyanide metabolism.