Synthesis Of Sulfur-containing Amino Acids Research Articles

Copper-based grape pest management has impacted wine aroma

Despite the high energetic cost of the reduction of sulfate to H2S, required for the synthesis of sulfur-containing amino acids, some wine Saccharomyces cerevisiae strains have been reported to produce excessive amounts of H2S during alcoholic fermentation, which is detrimental to wine quality. Surprisingly, in the presence of sulfite, used as a preservative, wine strains produce more H2S than wild (oak) or wine velum (flor) isolates during fermentation. Since copper resistance caused by the amplification of the sulfur rich protein Cup1p is a specific adaptation trait of wine strains, we analyzed the link between copper resistance mechanism, sulfur metabolism and H2S production. We show that a higher content of copper in the must increases the production of H2S, and that SO2 increases the resistance to copper. Using a set of 51 strains we observed a positive and then negative relation between the number of copies of CUP1 and H2S production during fermentation. This complex pattern could be mimicked using a multicopy plasmid carrying CUP1, confirming the relation between copper resistance and H2S production. The massive use of copper for vine sanitary management has led to the selection of resistant strains at the cost of a metabolic tradeoff: the overproduction of H2S, resulting in a decrease in wine quality.

Enhancing Metabolism and Milk Production Performance in Periparturient Dairy Cattle through Rumen-Protected Methionine and Choline Supplementation.

For dairy cattle to perform well throughout and following lactations, precise dietary control during the periparturient phase is crucial. The primary issues experienced by periparturient dairy cows include issues like decreased dry matter intake (DMI), a negative energy balance, higher levels of non-esterified fatty acids (NEFA), and the ensuing inferior milk output. Dairy cattle have always been fed a diet high in crude protein (CP) to produce the most milk possible. Despite the vital function that dairy cows play in the conversion of dietary CP into milk, a sizeable percentage of nitrogen is inevitably expelled, which raises serious environmental concerns. To reduce nitrogen emissions and their production, lactating dairy cows must receive less CP supplementation. Supplementing dairy cattle with rumen-protected methionine (RPM) and choline (RPC) has proven to be a successful method for improving their ability to use nitrogen, regulate their metabolism, and produce milk. The detrimental effects of low dietary protein consumption on the milk yield, protein yield, and dry matter intake may be mitigated by these nutritional treatments. In metabolic activities like the synthesis of sulfur-containing amino acids and methylation reactions, RPM and RPC are crucial players. Methionine, a limiting amino acid, affects the production of milk protein and the success of lactation in general. According to the existing data in the literature, methionine supplementation has a favorable impact on the pathways that produce milk. Similarly, choline is essential for DNA methylation, cell membrane stability, and lipid metabolism. Furthermore, RPC supplementation during the transition phase improves dry matter intake, postpartum milk yield, and fat-corrected milk (FCM) production. This review provides comprehensive insights into the roles of RPM and RPC in optimizing nitrogen utilization, metabolism, and enhancing milk production performance in periparturient dairy cattle, offering valuable strategies for sustainable dairy farming practices.

Redox regulation of enzymes involved in sulfate assimilation and in the synthesis of sulfur-containing amino acids and glutathione in plants.

Sulfur is essential in plants because of its presence in numerous molecules including the two amino acids, cysteine, and methionine. Cysteine serves also for the synthesis of glutathione and provides sulfur to many other molecules including protein cofactors or vitamins. Plants absorb sulfate from their environment and assimilate it via a reductive pathway which involves, respectively, a series of transporters and enzymes belonging to multigenic families. A tight control is needed to adjust each enzymatic step to the cellular requirements because the whole pathway consumes energy and produces toxic/reactive compounds, notably sulfite and sulfide. Glutathione is known to regulate the activity of some intermediate enzymes. In particular, it provides electrons to adenosine 5′-phosphosulfate reductases but also regulates the activity of glutamate-cysteine ligase by reducing a regulatory disulfide. Recent proteomic data suggest a more extended post-translational redox control of the sulfate assimilation pathway enzymes and of some associated reactions, including the synthesis of both sulfur-containing amino acids, cysteine and methionine, and of glutathione. We have summarized in this review the known oxidative modifications affecting cysteine residues of the enzymes involved. In particular, a prominent regulatory role of protein persulfidation seems apparent, perhaps because sulfide produced by this pathway may react with oxidized thiol groups. However, the effect of persulfidation has almost not yet been explored.

Transcriptome Analysis of Soybean in Response to Different Sulfur Concentrations

Sulfur is an indispensable nutrient for plant growth and development, and is important in the synthesis of sulfur-containing amino acids. Although several studies on the effects of some macronutrients, including nitrogen and phosphorus, have been conducted on the performance of several crops at the genomic level, studies on the effect of sulfur on crop performance are limited. Therefore, this study aimed to examine the effect of different sulfur concentration on the transcriptome of soybean. Additionally, soybean yield parameters were also examined. Two soybean varieties, DND252 and HN84, were exposed to low and high concentrations of sulfur, and differentially expressed genes (DEGs) were identified using transcriptome analysis. The study results showed that the DEGs identified in the DND252 variety were involved in stimuli response, DNA binding and cell periphery under low sulfur concentrations. Also, the DEGs identified under high sulfur concentration were involved in membrane and membrane parts. Additionally, DEGs identified in the HN84 variety under low sulfur concentrations had similar functions as those identified in DND252 under high sulfur concentrations, indicating that HN84 was more sensitive to sulfur concentration changes than DND252. However, under higher sulfur concentrations, the DEGs identified in HN84 were primarily involved in membrane and membrane parts, indicating that high sulfur can cause cell membrane damage. Furthermore, soybean grown using 2.0 mmol/L sulfur had the best yield. The findings of this study identified candidate genes for the breeding and development of sulfur-efficient soybean varieties.

Gene mining of sulfur-containing amino acid metabolic enzymes in soybean

The genes of sulfur-containing amino acid synthetases in soybean are essential for the synthesis of sulfur-containing amino acids. Gene mining of these enzymes is the basis for the molecular assistant breeding of high sulfur-containing amino acids in soybean. In this study, using software BioMercator2.1, 113 genes of sulfur-containing amino acid enzymes and 33 QTLs controlling the sulfur-containing amino acids content were mapped onto Consensus Map 4.0, which was integrated by genetic and physical maps of soybean. Sixteen candidate genes associated to the synthesis of sulfur-containing amino acids were screened based on the synteny between gene loci and QTLs, and the effect values of QTLs. Through a bioinformatic analysis of the copy number, SNP information, and expression profile of candidate genes, 12 related enzyme genes were identified and mapped on 8 linkage groups, such as D1a, M, A2, K, and G. The genes corresponding to QTL regions can explain 6%?38.5% genetic variation of sulfur-containing amino acids, and among them, the indirect effect values of 9 genes were more than 10%. These 12 genes were involved in sulfur-containing amino acid metabolism and were highly expressed in the cotyledons and flowers, showing an abundance of SNPs. These genes can be used as candidate genes for the development of functional markers, and it will lay a foundation for molecular design breeding in soybean.

Visualization of Imbalances in Sulfur Assimilation and Synthesis of Sulfur-Containing Amino Acids at the Single-Cell Level

We describe genetically encoded sensors which transmit elevated cytosolic concentrations of O-acetyl serine (OAS) and O-acetyl homoserine (OAH)-intermediates of l-cysteine and l-methionine synthesis-into an optical output. The sensor pSenOAS3 elicits 7.5-fold-increased fluorescence in cultures of a Corynebacterium glutamicum strain that excrete l-cysteine. Determination of the cytosolic OAS concentration revealed an increase to 0.13 mM, whereas the concentration in the reference strain was below the detection limit, indicating that incorporation of assimilatory sulfur is limited in the strain studied. In another strain, overexpression of metX encoding homoserine acetyltransferase resulted in an 8-fold increase in culture fluorescence at a cytosolic OAH concentration of 0.76 mM. We also assayed for consequences of extracellular sulfur supply and observed a graded fluorescence increase at decreasing sulfur concentrations below 400 μM. Overall, this demonstrates the usefulness of the sensors for monitoring intracellular sulfur availability. The sensors also enable monitoring at the single-cell level, and since related and close homologs of the transcription factor used in the constructed sensors are widespread among bacteria, this technology offers a new possibility of assaying in vivo for sulfur limitation and of doing this at the single-cell level.

Cysteine as a sustainable sulfur reagent for the protecting-group-free synthesis of sulfur-containing amino acids: biomimetic synthesis of l-ergothioneine in water

Biomass-derived cysteine was used as a sustainable sulfur source for the synthesis of rare sulfur-containing amino acids, such as L-ergothioneine (4), which might be a new vitamin, and various L- or D-2-thiohistidine compounds. Key in this simple, one-pot two-step procedure in water is a bromine-induced regioselective introduction of cysteine followed by a novel thermal cleavage reaction in the presence of thiols, a safer alternative to hazardous red phosphorus. Besides avoiding hazardous sulfur reagents, the new protecting-group-free approach reduces drastically the total number of steps, compared to described procedures. The main drawback, i.e. handling of liquid bromine as an activating and oxidizing reagent in water, was addressed by evaluating four alternative methods using in situ generation of bromine or HOBr, and first encouraging results are described.

Roles for nucleotide phosphatases in sulfate assimilation and skeletal disease

Sulfur is an essential element to all kingdoms of life and is used in essential cellular processes including the synthesis of sulfur-containing amino acids, maintenance of cellular redox states, and incorporation into various metabolites. Inorganic sulfate, the most abundant source of environmental sulfur, is metabolized into two commonly formed nucleotide precursors: adenosine 5’-phosphosulfate (APS) and 3’-phosphoadenosine 5’-phosphosulfate (PAPS). Donation of activated sulfur occurs through a broad range of enzymatic reactions many of which consume PAPS thereby producing 3’-phosphoadenosine 5’-phosphate (PAP). Two classes of 3’-nucleotide phosphatases then hydrolyze PAP into 5’-AMP: one is evolutionarily conserved from bacteria to man and localizes to the cytoplasmic compartment, while the other is restricted to a subset of eukaryotes and is active within the Golgi lumen. Interestingly, both classes of 3’-nucleotidase are members of a structurally conserved family of lithium-inhibited phosphatases that are targets of the drug in a variety of organisms. In this review we provide an overview of sulfur assimilation and the broad regulatory roles that 3’-nucleotidases play in processes ranging from halotolerance to glycosaminoglycan sulfation. In addition, we discuss recent plant and animal studies that emphasize roles for 3’-nucleotidase function in developmental biology, physiology, and in a rare subset of human patients with skeletal abnormalities.

The Seed Composition of Arabidopsis Mutants for the Group 3 Sulfate Transporters Indicates a Role in Sulfate Translocation within Developing Seeds

Sulfate is required for the synthesis of sulfur-containing amino acids and numerous other compounds essential for the plant life cycle. The delivery of sulfate to seeds and its translocation between seed tissues is likely to require specific transporters. In Arabidopsis (Arabidopsis thaliana), the group 3 plasmalemma-predicted sulfate transporters (SULTR3) comprise five genes, all expressed in developing seeds, especially in the tissues surrounding the embryo. Here, we show that sulfur supply to seeds is unaffected by T-DNA insertions in the SULTR3 genes. However, remarkably, an increased accumulation of sulfate was found in mature seeds of four mutants out of five. In these mutant seeds, the ratio of sulfur in sulfate form versus total sulfur was significantly increased, accompanied by a reduction in free cysteine content, which varied depending on the gene inactivated. These results demonstrate a reduced capacity of the mutant seeds to metabolize sulfate and suggest that these transporters may be involved in sulfate translocation between seed compartments. This was further supported by sulfate measurements of the envelopes separated from the embryo of the sultr3;2 mutant seeds, which showed differences in sulfate partitioning compared with the wild type. A dissection of the seed proteome of the sultr3 mutants revealed protein changes characteristic of a sulfur-stress response, supporting a role for these transporters in providing sulfate to the embryo. The mutants were affected in 12S globulin accumulation, demonstrating the importance of intraseed sulfate transport for the synthesis and maturation of embryo proteins. Metabolic adjustments were also revealed, some of which could release sulfur from glucosinolates.

The sulfocyanic theory on the origin of life: towards a critical reappraisal of an autotrophic theory

In the early 1930s, Alfonso L. Herrera proposed his so-called sulfocyanic theory on the origin of life, an autotrophic proposal on the first living beings according to which NH4SCN and H2CO acted as raw materials for the synthesis of bio-organic compounds inside primordial photosynthetic protoplasmic structures. Although the work of Herrera is frequently cited in historical analysis of the development of the origin of life studies, very little attention has been given to the chemical significance of the reactions he published. In this paper we report the results of our search for amino acids obtained from a reactive mixture used by Herrera from 1933 onwards. Chromatograms using the high-pressure liquid chromatography (HPLC) technique suggest the presence of several amino acids, the total yield being 2% of the initial thiocyanate used. Preliminary identification based on HPLC retention times suggests the presence of glycine, alanine, cysteine and methionine. Alanine was the most abundant amino acid in all samples of fractionated material analysed. Although the starting materials used by Herrera were determined by his autotrophic hypothesis on the origin of cells, our results show that his experiments may provide insights into the abiotic synthesis of sulfur-containing amino acids within the framework of a heterotrophic emergence of life.

Regulation of sulfate transport and synthesis of sulfur-containing amino acids

Recent research indicates that several sulfate transporters - exhibiting different tissue specificities and modes of expression - may play distinct roles in sulfate uptake within specific tissues and in long-distance sulfate translocation. The transcription levels of particular genes and feedback inhibition of serine acetyltransferase play major roles in regulating sulfur assimilation and cysteine synthesis. O-acetylserine and glutathione presumably act within the cysteine synthesis pathway as derepressor and repressor, respectively. A unique autoregulatory mechanism that stabilizes mRNA levels has recently been proposed for the regulation of methionine synthesis.

Regulation of sulfate transport and synthesis of sulfur-containing amino acids

Recent research indicates that several sulfate transporters — exhibiting different tissue specificities and modes of expression — may play distinct roles in sulfate uptake within specific tissues and in long-distance sulfate translocation. The transcription levels of particular genes and feedback inhibition of serine acetyltransferase play major roles in regulating sulfur assimilation and cysteine synthesis. O-acetylserine and glutathione presumably act within the cysteine synthesis pathway as derepressor and repressor, respectively. A unique autoregulatory mechanism that stabilizes mRNA levels has recently been proposed for the regulation of methionine synthesis.

Importance of sulfhydryl in the treatment of corneal and X-ray burns

1. 1. A sulfhydryl therapy has been employed in treating a series of more than 500 burns involving injury to the eyes and adjacent areas over a period of five years. 2. 2. Results observed indicate advantages over other methods expressed in (1) ability to heal x-ray burns in which tissue was devitalized or ulcerated condition and infection were present, (2) healing with less chance of development of symblepharon, (3) faster healing, (4) lack of scarring, and (5) absence of infection. 3. 3. The product used, hydrosulphosol, presents sulfur in a “free” colloidal state with a high concentration of sulfhydryl suggesting availability of sulfur in a form that can be utilized by the body in the synthesis of sulfur-containing amino acids. 4. 4. A review of the literature reveals the importance of sulfur-containing compounds in the eye which compounds have been shown to constitute almost one-half of the mineral content of the lens, and are connected with such functions as tissue respiration, oxygen transport, detoxication, capsular permeability, protein synthesis and general metabolic efficiency. The importance of these compounds is referred to in other organs of the body—the liver, kidneys, spleen, etc. 5. 5. In addition to its use as a treatment for burns, this product has been used in conjunction with penicillin in the treatment of multiple corneal ulcers with results not heretofore observed when using penicillin alone. 6. 6. No contraindications have been observed for this product when used with other medicants. Also, there has been no evidence of any toxic reaction following free and repeated application and use of this sulfhydryl-bearing solution.