A cascade of sulfur transferases delivers sulfur to the sulfur-oxidizing heterodisulfide reductase-like complex.

A heterodisulfide reductase-like complex (sHdr) and novel lipoate-binding proteins (LbpAs) are central players of a wide-spread pathway of dissimilatory sulfur oxidation. Bioinformatic analysis demonstrate that the cytoplasmic sHdr-LbpA systems are always accompanied by sets of sulfur transferases (DsrE proteins, TusA, and rhodaneses). The exact composition of these sets may vary depending on the organism and sHdr system type. To enable generalizations, we studied model sulfur oxidizers from distant bacterial phyla, that is, Aquificota and Pseudomonadota. DsrE3C of the chemoorganotrophic Alphaproteobacterium Hyphomicrobium denitrificans and DsrE3B from the Gammaproteobacteria Thioalkalivibrio sp. K90mix, an obligate chemolithotroph, and Thiorhodospira sibirica, an obligate photolithotroph, are homotrimers that donate sulfur to TusA. Additionally, the hyphomicrobial rhodanese-like protein Rhd442 exchanges sulfur with both TusA and DsrE3C. The latter is essential for sulfur oxidation in Hm. denitrificans. TusA from Aquifex aeolicus (AqTusA) interacts physiologically with AqDsrE, AqLbpA, and AqsHdr proteins. This is particularly significant as it establishes a direct link between sulfur transferases and the sHdr-LbpA complex that oxidizes sulfane sulfur to sulfite. In vivo, it is unlikely that there is a strict unidirectional transfer between the sulfur-binding enzymes studied. Rather, the sulfur transferases form a network, each with a pool of bound sulfur. Sulfur flux can then be shifted in one direction or the other depending on metabolic requirements. A single pair of sulfur-binding proteins with a preferred transfer direction, such as a DsrE3-type protein towards TusA, may be sufficient to push sulfur into the sink where it is further metabolized or needed.

Mycobacterial biotin synthases require an auxiliary protein to convert dethiobiotin into biotin.

Lipid biosynthesis in the pathogen Mycobacterium tuberculosis depends on biotin for posttranslational modification of key enzymes. However, the mycobacterial biotin synthetic pathway is not fully understood. Here, we show that rv1590, a gene of previously unknown function, is required by M. tuberculosis to synthesize biotin. Chemical-generic interaction experiments mapped the function of rv1590 to the conversion of dethiobiotin to biotin, which is catalyzed by biotin synthases (BioB). Biochemical studies confirmed that in contrast to BioB of Escherichia coli, BioB of M. tuberculosis requires Rv1590 (which we named "biotin synthase auxiliary protein" or BsaP), for activity. We found homologs of bsaP associated with bioB in many actinobacterial genomes, and confirmed that BioB of Mycobacterium smegmatis also requires BsaP. Structural comparisons of BsaP-associated biotin synthases with BsaP-independent biotin synthases suggest that the need for BsaP is determined by the [2Fe-2S] cluster that inserts sulfur into dethiobiotin. Our findings open new opportunities to seek BioB inhibitors to treat infections with M. tuberculosis and other pathogens.

YeeD is an essential partner for YeeE-mediated thiosulfate uptake in bacteria and regulates thiosulfate ion decomposition.

Uptake of thiosulfate ions as an inorganic sulfur source from the environment is important for bacterial sulfur assimilation. Recently, a selective thiosulfate uptake pathway involving a membrane protein YeeE (TsuA) in Escherichia coli was characterized. YeeE-like proteins are conserved in some bacteria, archaea, and eukaryotes. However, the precise function of YeeE, along with its potential partner protein in the thiosulfate ion uptake pathway, remained unclear. Here, we assessed selective thiosulfate transport via Spirochaeta thermophila YeeE in vitro and characterized E. coli YeeD (TsuB) as an adjacent and essential protein for YeeE-mediated thiosulfate uptake in vivo. We further showed that S. thermophila YeeD possesses thiosulfate decomposition activity and that a conserved cysteine in YeeD was modified to several forms in the presence of thiosulfate. Finally, the crystal structures of S. thermophila YeeE-YeeD fusion proteins at 3.34-Å and 2.60-Å resolutions revealed their interactions. The association was evaluated by a binding assay using purified S. thermophila YeeE and YeeD. Based on these results, a model of the sophisticated uptake of thiosulfate ions by YeeE and YeeD is proposed.

Pathogenic/likely pathogenic mutations identified in Vietnamese children diagnosed with autism spectrum disorder using high-resolution SNP genotyping platform.

Among the most prevalent neurodevelopmental disorders, Autism Spectrum Disorder (ASD) is highly diverse showing a broad phenotypic spectrum. ASD also couples with a broad range of mutations, both de novo and inherited. In this study, we used a proprietary SNP genotyping chip to analyze the genomic DNA of 250 Vietnamese children diagnosed with ASD. Our Single Nucleotide Polymorphism (SNP) genotyping chip directly targets more than 800 thousand SNPs in the genome. Our primary focus was to identify pathogenic/likely pathogenic mutations that are potentially linked to more severe symptoms of autism. We identified and validated 23 pathogenic/likely pathogenic mutations in this initial study. The data shows that these mutations were detected in several cases spanning multiple biological pathways. Among the confirmed SNPs, mutations were identified in genes previously known to be strongly associated with ASD such as SLCO1B1, ACADSB, TCF4, HCP5, MOCOS, SRD5A2, MCCC2, DCC, and PRKN while several other mutations are known to associate with autistic traits or other neurodevelopmental disorders. Some mutations were found in multiple patients and some patients carried multiple pathogenic/likely pathogenic mutations. These findings contribute to the identification of potential targets for therapeutic solutions in what is considered a genetically heterogeneous neurodevelopmental disorder.

Exploring the role of LIAS-related cuproptosis in systemic lupus erythematosus.

BACKGROUND: Cuproptosis is a novel mode of cell death, which is strongly related to energy metabolism in mitochondria and regulated by protein lipoylation. Currently, the molecular mechanisms of cuproptosis-related genes (CRGs) involved in systemic lupus erythematosus (SLE) largely remained unclear, our study is aimed to explore the mechanisms of cuproptosis and CRGs involved in SLE. METHODS: Bulk RNA-seq datasets were collected to display the expressions of CRGs in peripheral blood mononuclear cells (PBMCs) of SLE and healthy individuals, and then ROC analysis was used to establish the diagnostic models of CRGs. Next, the immune infiltration analyses were applied to reveal the difference of immune cells infiltration in LIAS-low and LIAS-high group. Additionally, WGCNA analysis was performed to find the gene modules significantly correlated with the LIAS expression level. We also performed the functional enrichment analyses for LIAS-related gene modules to determine the potential pathways involved in the development of SLE. Finally, scRNA-seq dataset was used to cluster immune cell subsets, reveal the activated pathways, and study cell-cell interactions in LIAS-low and LIAS-high cells. RESULT: We found CDKN2A was significantly increased and LIAS was significantly decreased in SLE patients compared with healthy individuals. The AUC score showed that LIAS had a great diagnostic value than other CRGs. Additionally, the results of immune infiltration analyses showed that immune cells proportion were diverse in LIAS-low and LIAS-high samples. The gene sets related to LIAS expression level were involved in dephosphorylation of JAK1 by SHP1, phosphorylation of STAT2, cytokine signaling in immune system, expression of interferon-alpha and beta, inhibition of JAK kinase activity by SOCS1/3, and so on. Finally, the results of cell-cell communication showed that CCL- (CCL5 + CCR1) and ANNEXIN- (ANXA1 + FPR1) might play an essential role in the communication network between LIAS-low and LIAS-high cells. CONCLUSION: Above findings inferred that LIAS-mediated cuproptosis might involve in a comprehensive cellular and molecular mechanism to cause the occurrence and development of SLE.

MOCOS-associated renal syndrome in a Brown Swiss cattle.

BACKGROUND: A recessive form of MOCOS-associated xanthinuria type II is described in Tyrolean grey cattle. A similar case was identified in a 5-month-old Brown Swiss calf with hoof overgrowth, rough coat, urine sediment, and pneumonia. HYPOTHESIS/OBJECTIVES: To characterize the disease phenotype, to evaluate its genetic etiology, and to determine the prevalence of the deleterious allele in the Brown Swiss population. ANIMALS: An affected calf, its parents, and 65 441 Swiss dairy cattle. METHODS: The affected animal was clinically examined and necropsied. Microarray genotyping was used to determine the genotypes and to assess the frequency of the MOCOS allele in a Brown Swiss control cohort. RESULTS: Ultrasonography revealed hyperechoic renal pyramids with multifocal distal shadowing and echogenic sediment in the urinary bladder. Necropsy revealed suppurative bronchopneumonia and urolithiasis. Histology revealed numerous nephroliths with multifocal chronic lymphohistiocytic interstitial infiltrates, fibrosis, tubular degeneration, chronic multifocal glomerulonephritis with sclerosis, and bilateral hydronephrosis. Dysplastic changes were observed in the corium of the claw and the cornea. Genetic testing identified the homozygous presence of a known MOCOS frameshift variant in the case. Both parents were heterozygous and the prevalence of carriers in genotyped Brown Swiss cattle was 1.4% (342/24337). CONCLUSIONS AND CLINICAL IMPORTANCE: The findings were consistent with the diagnosis of a recessive renal syndrome similar to xanthinuria type II described in Tyrolean grey cattle. The prevalence of the deleterious MOCOS allele is low in the Brown Swiss breed. However, mating of carriers should be avoided to prevent further losses.

Exogenous thiocyanate inhibits sulfurtransferase pathway and induces ß-cyanoalanine synthase pathway to enhance exogenous cyanide assimilation in rice plants.

Cyanide (CN-) assimilation in plants takes place by ß-cyanoalanine synthase (ß-CAS) and sulfurtransferase (ST), in which the ST pathway converts CN- into thiocyanate (SCN-). Both chemicals (CN- and SCN-) are frequently detected in the effluent of gold mining operations. In this connection, exogenous SCN- was applied to rice plants with CN- and compared with CN- alone to investigate its effects on CN- assimilation and degradation pathways. Interestingly, the CN- and SCN- content in both roots and shoots were increased with the increase in "CN-" treatments, but surprisingly their content under "SCN-+CN-" treatments did not show the similar trend. The increasing trend remained the same for CN- but the SCN- content was constant with increasing CN- concentrations in comparison with the control (SCN- alone). Additionally, the assimilation rates of CN- in rice plants under "SCN-+CN-" treatments were significantly higher than "CN-" treatments. The application of SCN- with CN- mostly alters the expression of both ß-CAS and ST-associated genes. On one side, the application of SCN- significantly repressed the expression of genes encoded with ST in rice plants, but on the other side, it significantly up-regulated the expression of the ß-CAS gene located in mitochondria. These results reveal that the application of exogenous SCN- increases CN- assimilation rates by inhibiting the ST pathway and stimulating the ß-CAS pathway. This study would provide new insight into the positive effects of exogenous SCN- in increasing CN- assimilation by altering the degradation pathways in rice plants.

Lipoylation is dependent on the ferredoxin FDX1 and dispensable under hypoxia in human cells.

Iron-sulfur clusters (ISC) are essential cofactors that participate in electron transfer, environmental sensing, and catalysis. Amongst the most ancient ISC-containing proteins are the ferredoxin (FDX) family of electron carriers. Humans have two FDXs- FDX1 and FDX2, both of which are localized to mitochondria, and the latter of which is itself important for ISC synthesis. We have previously shown that hypoxia can eliminate the requirement for some components of the ISC biosynthetic pathway, but FDXs were not included in that study. Here, we report that FDX1, but not FDX2, is dispensable under 1% O2 in cultured human cells. We find that FDX1 is essential for production of the lipoic acid cofactor, which is synthesized by the ISC-containing enzyme lipoyl synthase. While hypoxia can rescue the growth phenotype of either FDX1 or lipoyl synthase KO cells, lipoylation in these same cells is not rescued, arguing against an alternative biosynthetic route or salvage pathway for lipoate in hypoxia. Our work reveals the divergent roles of FDX1 and FDX2 in mitochondria, identifies a role for FDX1 in lipoate synthesis, and suggests that loss of lipoic acid can be tolerated under low oxygen tensions in cell culture.

Candidate causative variant for xanthinuria in a Domestic Shorthair cat.

Xanthinuria is a clinically significant form of urolithiasis in cats with poor clinical outcomes and limited treatment options. In humans, xanthinuria has an autosomal recessive mode of inheritance, with variants in xanthine dehydrogenase (XDH) and molybdenum cofactor sulfurase (MOCOS) responsible for cases. While causative genetic variants have not been identified in the domestic cat, a recessive mode of inheritance has been suggested. DNA was extracted from EDTA-stabilised blood obtained from a Domestic Shorthair cat with clinically confirmed xanthinuria. Whole-genome sequencing and variant assessment in XDH and MOCOS identified XDH:c.2042C>T (XDH:p.(A681V)) as a candidate causative variant for xanthinuria in this cat. The variant is located in a highly conserved part of the molybdenum-pterin co-factor domain, responsible for catalysing the hydroxylation of hypoxanthine to xanthine and uric acid. Variants in this domain of XDH have been shown to disrupt enzyme function and to cause xanthinuria in other species. When assessed in the wider cat population, the variant had an allele frequency of 15.8%, with 0.9% of the animals assessed homozygous for the alternative allele. Cats diagnosed with xanthinuria should be tested for this variant to validate its clinical relevance in the wider population.

Differential Roles of Cystathionine Gamma-Lyase and Mercaptopyruvate Sulfurtransferase in Hapten-Induced Colitis and Contact Dermatitis in Mice.

Hydrogen sulfide (H2S) has been shown to act as both anti-inflammatory and pro-inflammatory mediators. Application of H2S donors generally protects against inflammation; however, experimental results using mice lacking endogenous H2S-producing enzymes, such as cystathionine γ-lyase (CTH) and mercaptopyruvate sulfurtransferase (MPST), are often contradictory. We herein examined two types of model hapten-induced inflammation models, colitis (an inflammatory bowel disease model of mucosal immunity) and contact dermatitis (a type IV allergic model of systemic immunity), in CTH-deficient (Cth-/-) and MPST-deficient (Mpst-/-) mice. Both mice exhibited no significant alteration from wild-type mice in trinitrobenzene sulfonic acid (Th1-type hapten)-induced colitis (a Crohn's disease model) and oxazolone (Th1/Th2 mix-type; Th2 dominant)-induced colitis (an ulcerative colitis model). However, Cth-/- (not Mpst-/-) mice displayed more exacerbated phenotypes in trinitrochlorobenzene (TNCB; Th1-type)-induced contact dermatitis, but not oxazolone, at the delayed phase (24 h post-administration) of inflammation. CTH mRNA expression was upregulated in the TNCB-treated ears of both wild-type and Mpst-/- mice. Although mRNA expression of pro-inflammatory cytokines (IL-1ß and IL-6) was upregulated in both early (2 h) and delayed phases of TNCB-triggered dermatitis in all genotypes, that of Th2 (IL-4) and Treg cytokines (IL-10) was upregulated only in Cth-/- mice, when that of Th1 cytokines (IFNγ and IL-2) was upregulated in wild-type and Mpst-/- mice at the delayed phase. These results suggest that (upregulated) CTH or H2S produced by it helps maintain Th1/Th2 balance to protect against contact dermatitis.

Novel LIAS variants in a patient with epilepsy and profound developmental disabilities.

Multiple mitochondrial enzymes employ lipoic acid as a coenzyme. Pathogenic variants in LIAS, encoding lipoic acid synthase (LIAS), are associated with autosomal recessive LIAS-related disorder (OMIM# 614462). This disorder is characterized by infantile-onset hypotonia, profound psychomotor delay, epileptic encephalopathy, nonketotic hyperglycinemia, and lactic acidosis. We present the case of a 20-year-old female who experienced developmental deficits at the age of 6 months and began to have seizures at 3 years of age. Exome sequencing revealed compound heterozygous novel variants in LIAS, designated c.277delC (p.Leu93Ter) and c.542A > T (p.Asp181Val). The p.Leu93Ter variant is predicted to cause loss of function due to the severe truncation of the encoded protein. To examine the p.Asp181Val variant, functional analysis was performed using Baker's yeast (Saccharomyces cerevisiae) lacking LIP5, the homologue of human LIAS. Wild-type LIAS promoted oxidative growth of the lip5∆ yeast strain. In contrast, lip5∆ yeast expressing p.Asp181Val exhibited poor growth, similar to known pathogenic variants, p.Asp215Glu and p.Met310Thr. Our work has expanded the phenotypic and genotypic spectrum of LIAS-related disorder and established the use of the yeast model as a system for functional study of novel missense variants in LIAS.

Glioblastoma cell motility depends on enhanced oxidative stress coupled with mobilization of a sulfurtransferase.

Cell motility is critical for tumor malignancy. Metabolism being an obligatory step in shaping cell behavior, we looked for metabolic weaknesses shared by motile cells across the diverse genetic contexts of patients' glioblastoma. Computational analyses of single-cell transcriptomes from thirty patients' tumors isolated cells with high motile potential and highlighted their metabolic specificities. These cells were characterized by enhanced mitochondrial load and oxidative stress coupled with mobilization of the cysteine metabolism enzyme 3-Mercaptopyruvate sulfurtransferase (MPST). Functional assays with patients' tumor-derived cells and -tissue organoids, and genetic and pharmacological manipulations confirmed that the cells depend on enhanced ROS production and MPST activity for their motility. MPST action involved protection of protein cysteine residues from damaging hyperoxidation. Its knockdown translated in reduced tumor burden, and a robust increase in mice survival. Starting from cell-by-cell analyses of the patients' tumors, our work unravels metabolic dependencies of cell malignancy maintained across heterogeneous genomic landscapes.

XDH genotypes through gene-gene interactions with NUDT15 affect azathioprine-induced leukopenia in Chinese patients.

Aim: To investigate whether genotypes of XDH, GMPS and MOCOS were associated with azathioprine-induced adverse drug reaction (ADR) and had the gene-gene interactions with NUDT15 rs116855232 to induce leukopenia. Methods: Patients who had taken azathioprine were recruited. Genotyping of those gene was performed. Risk factor to ADR was analyzed by logistic regression. The generalized multifactor dimensionality reduction (GMDR) was assessed based on gene-gene interactions with ADR. Results: A total of 111 patients were included in this study, all of whom were Han Chinese. XDH rs2295475 was a risk factor of myelotoxicity (p = 0.022). NUDT15 rs116855232 was a risk factor of myelotoxicity, grade ≥2 leukopenia and drug treatment termination (p-values were <0.05). Rs2295475 and rs116855232 had a gene-gene interaction. The model was associated with grade ≥2 leukopenia (OR: 17.99; 95% CI: 4.11-78.81). Conclusion: Combined testing genotype for rs2295475 and rs116855232 could improve the prediction of azathioprine-induced leukopenia.

Metabolic and Genetic Evaluation in Children with Nephrolithiasis.

OBJECTIVE: To evaluate metabolic and genetic abnormalities in children with nephrolithiasis attending a referral center in North India. METHODS: The patients aged 1-18 y old with nephrolithiasis underwent biochemical evaluation and whole-exome sequencing. The authors evaluated for monogenic variants in 56 genes and compared allele frequency of 39 reported polymorphisms between patients and 1739 controls from the GenomeAsia 100 K database. RESULTS: Fifty-four patients, aged 9.1 ± 3.7 y were included. Stones were bilateral in 42.6%, familial in 33.3%, and recurrent in 25.9%. The most common metabolic abnormalities were hypercalciuria (35.2%), hyperoxaluria (24.1%), or both (11.1%), while xanthinuria (n = 3), cystinuria (n = 1), and hyperuricosuria (n = 1) were rare. Exome sequencing identified an etiology in 6 (11.1%) patients with pathogenic/likely pathogenic causative variants. Three variants in MOCOS and one in ATP7B were pathogenic; likely pathogenic variants included MOCOS (n = 2), AGXT, and SLC7A9 (n = 1, each). Causality was not attributed to two SLC34A1 likely pathogenic variants, due to lack of matching phenotype and dominant family history. Compared to controls, allele frequency of the polymorphism TRPV5 rs4252402 was significantly higher in familial stone disease (allele frequency 0.47 versus 0.53; OR 3.2, p = 0.0001). CONCLUSION: The chief metabolic abnormalities were hypercalciuria and hyperoxaluria. A monogenic etiology was identified in 11% with pathogenic or likely pathogenic variants using a gene panel for nephrolithiasis. Heterozygous missense variants in the sodium-phosphate cotransporter SLC34A1 were common and required evaluation for attributing pathogenicity. Rare polymorphisms in TRPV5 might increase the risk of familial stones. These findings suggest that a combination of metabolic and genetic evaluation is useful for determining the etiology of nephrolithiasis.

Heart and kidney H2S production is reduced in hypertensive and older rats.

The prevalence of hypertension increases with age, but the mechanisms linking this phenomenon are not well understood. Hydrogen sulfide (H2S) may be involved in this process, as it plays a role in the cardiovascular system, affecting blood pressure and heart and kidney functions. The aim of this study was to evaluate the influence of hypertension and aging on sulfur-containing compounds metabolism in the hearts and kidneys of Wistar Kyoto (WKY) and Spontaneously Hypertensive Rats (SHR) of different age groups. We determined the expression and activity of four enzymes participating in H2S production: cystathionine beta-synthase (CBS), cystathionine gamma-lyase (CTH), 3-mercaptopyruvate sulfurtransferase (MPST), and thiosulfate sulfurtransferase (TST). The levels of reduced/oxidized glutathione, cysteine, cystine, and cystathionine, and the ability of tissues to form hydrogen sulfide were also investigated. Tissues obtained from younger WKY rats produced the highest amounts of H2S. The effect of hypertension on the metabolism of sulfur-containing compounds was manifested by a decrease in sulfane sulfur concentrations in heart homogenates and a decrease in CTH activity in the kidneys. The hearts and kidneys of older WKY rats were characterized by lower MPST or CTH gene expression, respectively, compared to younger animals. Our study demonstrates that hypertension and aging influence cardiac and renal sulfur-containing compounds metabolism and reduce H2S production. Furthermore, we showed that MPST plays a major role in the production of hydrogen sulfide in the heart and CTH in the kidneys of rats.

Escherichia coli tRNA 2-selenouridine synthase SelU selects its prenyl substrate to accomplish its enzymatic function.

Bacterial tRNA 2-selenouridine synthase (SelU) in vitro converts S2U-RNA to its selenium analog (Se2U-RNA) in a two-step process: (i) geranylation of S2U-RNA (with geranyl pyrophosphate, gePP), and (ii) selenation of the resulting geS2U-RNA (with the selenophosphate anion, SePO33-). Using an S2U-containing anticodon stem-loop fragment derived from tRNALys (S2U-RNA) and recombinant SelU with an MBP tag, we found that only geranyl (C10) pyrophosphate is the substrate for this enzyme, while other pyrophosphates such as isopentenyl (C5), dimethylallyl (C5), farnesyl (C15) and geranylgeranyl (C20) are not. Interestingly, methyl (C1)- and C5-, C10-, and C15-prenyl-containing S2U-RNAs (which were chemically obtained) underwent the selenation reaction promoted by SelU, although the Se2U-RNA product was obtained in decreasing yields in the following order: geranyl ≥ farnesyl > dimethylallyl ≫ methyl. Microscale thermophoresis showed an affinity between gePP and SelU in the micromolar range, while the other pyrophosphates tested, such as isopentenyl, dimethylallyl, farnesyl and geranylgeranyl, either did not bind to the protein or their binding affinity was above 1 mM. These results agree well with the in silico analysis, with gePP being the best binding substrate (the lowest relative free energy of binding (ΔG) and a small solvent-accessible surface area (SASA)). These results suggest that SelU has high substrate specificity for the prenylation reaction (only gePP is accepted), whereas there is little discrimination for the selenation reaction. We therefore suggest that only gePP and the geranylated tRNA serve as substrates for the conversion of 2-thio-tRNAs to 2-seleno-tRNAs, as it is found in the bacterial system.

Sulfurtransferases and Cystathionine Beta-Synthase Expression in Different Human Leukemia Cell Lines.

The studies concerned the expression of sulfurtransferases and cystathionine beta-synthase in six human leukemia cell lines: B cell acute lymphoblastic leukemia-B-ALL (REH cells), T cell acute lymphoblastic leukemia-T-ALL (DND-41 and MOLT-4 cells), acute myeloid leukemia-AML (MV4-11 and MOLM-14 cells), and chronic myeloid leukemia-CML (K562 cells). Reverse transcription-polymerase chain reaction (RT-PCR) and Western blot analysis were performed to determine the expression of thiosulfate sulfurtransferase, 3-mercaptopyruvate sulfurtransferase, gamma-cystathionase, and cystathionine beta-synthase on the mRNA and protein level. Interestingly, we found significant differences in the mRNA and protein levels of sulfurtransferases and cystathionine beta-synthase in the studied leukemia cells. The obtained results may contribute to elucidating the significance of the differences between the studied cells in the field of sulfur compound metabolism and finding new promising ways to inhibit the proliferation of various types of leukemic cells by modulating the activity of sulfurtransferases, cystathionine beta-synthase, and, consequently, the change of intracellular level of sulfane sulfur as well as H2S and reactive oxygen species production.

Involvement of ß-cyanoalanine synthase (ß-CAS) and sulfurtransferase (ST) in cyanide (CN-) assimilation in rice seedlings.

In spite of available information demonstrating the assimilation of cyanide (CN-) by ß-cyanoalanine synthase (ß-CAS) in plants, involvement of sulfurtransferase (ST) in CN- assimilation in rice plants is still undefined. In this study, a microcosmic hydroponic system was used to investigate the involvement of ß-cyanoalanine synthase (ß-CAS) and sulfurtransferase (ST) in the CN- assimilation in rice seedlings under the exposure of potassium cyanide (KCN) in presence or absence of 1-amino-cyclopropane-1-carboxylic acid (ACC). Our results indicated that the measurable thiocyanate (SCN-) was detected in both rice roots and shoots under KCN exposure, and the abundances of ST-related transcripts were up-regulated significantly (p < 0.05), suggesting that the ST pathway is involved in CN- assimilation in the rice plants. The application of exogenous ACC significantly (p < 0.05) decreased the accumulation of CN- and SCN- in rice tissues after KCN exposures, and also up-regulated the expression of ß-CAS and ST genes and their enzymatic activities, suggesting a positive interaction between aminocyclopropane-1-carboxylate oxidase (ACO), ß-CAS and ST in rice plants during the CN- assimilation. This is the first attempt to experimentally clarify the involvement of ST in CN- assimilation in rice seedlings.

Genotype-Phenotype Dissociation in Two Taiwanese Children with Molybdenum Cofactor Deficiency Caused by MOCS2 Mutation.

BACKGROUND: To describe the genotype-phenotype dissociation in two Taiwanese patients with molybdenum cofactor deficiency (MoCoD) caused by MOCS2 gene mutations. PATIENT DESCRIPTION: Patient 1 exhibited early-onset neurological symptoms soon after birth, followed by subsequent myoclonic seizures and movement disorder. The brain magnetic resonance imaging (MRI) showed diffuse brain injury with cystic encephalomalacia along with bilateral globus pallidi involvement, hypoplasia of corpus callosum, and cerebellar atrophy. Patient 2 had a mild phenotype with prominent movement disorder after intercurrent illness, and the brain MRI showed selective injury of the bilateral globus pallidi and the cerebellum. Both patients had markedly low levels of plasma uric acid and harbored the same MOCS2 homozygous c.16C > T mutation. Patient 1 showed chronic regression of developmental milestones and died of respiratory failure at the age of 8 years, whereas patient 2 demonstrated improvement in motor function. CONCLUSION: Genotype-phenotype dissociation could be noted in patients with MoCoD due to MOCS2 mutation. Patients with neonatal seizures, developmental delay, movement disorder, and motor regression after an illness, as well as focal or bilateral involvement of the globus pallidi on the neuroimages, should undergo biochemical testing of plasma uric acid. A pronounced plasma uric acid level is a good indicator of MoCoD. Early diagnosis can allow early provision of adequate genetic counseling.

Pyridoxal-5-phosphate induced cardioprotection in aging associated with up-expression of cystathionine-γ-lyase, 3-mercaptopyruvate sulfurtransferase, and ATP-sensitive potassium channels.

BACKGROUND: In the present work, we investigated the cardioprotective potential of pyridoxal-5-phosphate (PLP) in old rats as a cofactor of enzymes that synthesize hydrogen sulphide (H2 S). MATERIALS AND METHODS: PLP was administered per os in a dose of 0.7 mg per kg daily for 2 weeks. Rats were divided into three groups (adult, old and old +PLP) of 20 animals. The cardiac mRNA levels of genes encoding H2 S-synthesizing enzymes cystathionine-γ-lyase (CSE) and 3-mercaptopyruvate sulfurtransferase (3-MST), uncoupling proteins (UCP3), subunits of ATP-sensitive potassium (KATP ) channels were determined using real-time polymerase chain reaction analysis. We also studied the effect of PLP-administration on the content of H2 S, oxidative stress, the activities of inducible and constitutive NO-synthase (iNOS, cNOS), arginase and nitrate reductase in the heart homogenates as well as cardiac resistance to ischemia-reperfusion in Langendorff-isolated heart model. RESULTS: It was shown that PLP restored mRNA levels of CSE, 3-MST and UCP3 genes, and H2 S content and also significantly increased the expression of SUR2 and Kir6.1 (2.2 and 3.3 times, respectively) in the heart of old rats. PLP significantly reduced the formation of superoxide, malondialdehyde, diene conjugates as well as the activity of iNOS and arginase. PLP significantly increased constitutive synthesis of NO and prevented reperfusion disturbances of the heart function after ischemia. CONCLUSIONS: Thus, PLP-administration in old rats was associated with up-expression of CSE, 3-MST, UCP3 and SUR2 and Kir6.1 subunits of KATP channels, and also increased cNOS activity and reduced oxidative stress and prevented reperfusion dysfunction of the heart in ischemia-reperfusion.