scholarly journals Role of Cystathionine β-Lyase in Catabolism of Amino Acids to Sulfur Volatiles by Genetic Variants of Lactobacillus helveticus CNRZ 32

2007 ◽  
Vol 73 (9) ◽  
pp. 3034-3039 ◽  
Author(s):  
Won-Jae Lee ◽  
Dattatreya S. Banavara ◽  
Joanne E. Hughes ◽  
Jason K. Christiansen ◽  
James L. Steele ◽  
...  
Keyword(s):  
Amino Acids ◽  
Genetic Variants ◽  
Solid Phase ◽  
Dimethyl Disulfide ◽  
Lactobacillus Helveticus ◽  
Gas Chromatography Mass Spectrometry ◽  
Null Mutant ◽  
Wild Type ◽  
Sulfur Containing

ABSTRACT Catabolism of sulfur-containing amino acids plays an important role in the development of cheese flavor. During ripening, cystathionine β-lyase (CBL) is believed to contribute to the formation of volatile sulfur compounds (VSCs) such as methanethiol and dimethyl disulfide. However, the role of CBL in the generation of VSCs from the catabolism of specific sulfur-containing amino acids is not well characterized. The objective of this study was to investigate the role of CBL in VSC formation by Lactobacillus helveticus CNRZ 32 using genetic variants of L. helveticus CNRZ 32 including the CBL-null mutant, complementation of the CBL-null mutant, and the CBL overexpression mutant. The formation of VSCs from methionine, cystathionine, and cysteine was determined in a model system using gas chromatography-mass spectrometry with solid-phase microextraction. With methionine as a substrate, CBL overexpression resulted in higher VSC production than that of wild-type L. helveticus CNRZ 32 or the CBL-null mutant. However, there were no differences in VSC production between the wild type and the CBL-null mutant. With cystathionine, methanethiol production was detected from the CBL overexpression variant and complementation of the CBL-null mutant, implying that CBL may be involved in the conversion of cystathionine to methanethiol. With cysteine, no differences in VSC formation were observed between the wild type and genetic variants, indicating that CBL does not contribute to the conversion of cysteine.

scholarly journals Characterization of the Volatile Profile of Cultivated and Wild-Type Italian Celery (Apium graveolens L.) Varieties by HS-SPME/GC-MS

2021 ◽  
Vol 11 (13) ◽  
pp. 5855
Author(s):  
Samantha Reale ◽  
Valter Di Cecco ◽  
Francesca Di Donato ◽  
Luciano Di Martino ◽  
Aurelio Manzi ◽  
...  
Keyword(s):  
Solid Phase ◽  
Principal Component ◽  
Apium Graveolens ◽  
Gas Chromatography Mass Spectrometry ◽  
Bioactive Metabolites ◽  
Chemical Components ◽  
Volatile Profile ◽  
Wild Type ◽  
Multivariate Statistical ◽  
Clear Differentiation

Celery (Apium graveolens L.) is a vegetable belonging to the Apiaceae family that is widely used for its distinct flavor and contains a variety of bioactive metabolites with healthy properties. Some celery ecotypes cultivated in specific territories of Italy have recently attracted the attention of consumers and scientists because of their peculiar sensorial and nutritional properties. In this work, the volatile profiles of white celery “Sedano Bianco di Sperlonga” Protected Geographical Indication (PGI) ecotype, black celery “Sedano Nero di Torricella Peligna” and wild-type celery were investigated using head-space solid-phase microextraction combined with gas-chromatography/mass spectrometry (HS-SPME/GC-MS) and compared to that of the common ribbed celery. Exploratory multivariate statistical analyses were conducted using principal component analysis (PCA) on HS-SPME/GC-MS patterns, separately collected from celery leaves and petioles, to assess similarity/dissimilarity in the flavor composition of the investigated varieties. PCA revealed a clear differentiation of wild-type celery from the cultivated varieties. Among the cultivated varieties, black celery “Sedano Nero di Torricella Peligna” exhibited a significantly different composition in volatile profile in both leaves and petioles compared to the white celery and the prevalent commercial variety. The chemical components of aroma, potentially useful for the classification of celery according to the variety/origin, were identified.

scholarly journals Human Rev1 relies on insert-2 to promote selective binding and accurate replication of stabilized G-quadruplex motifs

2021 ◽  
Author(s):  
Amit Ketkar ◽  
Lane Smith ◽  
Callie Johnson ◽  
Alyssa Richey ◽  
Makayla Berry ◽  
...  
Keyword(s):  
Amino Acids ◽  
Mutation Frequency ◽  
Control Sequence ◽  
Wild Type ◽  
Binding Properties ◽  
High Affinity ◽  
G4 Dna ◽  
G Quadruplex ◽  
Forward Mutagenesis

Abstract We previously reported that human Rev1 (hRev1) bound to a parallel-stranded G-quadruplex (G4) from the c-MYC promoter with high affinity. We have extended those results to include other G4 motifs, finding that hRev1 exhibited stronger affinity for parallel-stranded G4 than either anti-parallel or hybrid folds. Amino acids in the αE helix of insert-2 were identified as being important for G4 binding. Mutating E466 and Y470 to alanine selectively perturbed G4 binding affinity. The E466K mutant restored wild-type G4 binding properties. Using a forward mutagenesis assay, we discovered that loss of hRev1 increased G4 mutation frequency >200-fold compared to the control sequence. Base substitutions and deletions occurred around and within the G4 motif. Pyridostatin (PDS) exacerbated this effect, as the mutation frequency increased >700-fold over control and deletions upstream of the G4 site more than doubled. Mutagenic replication of G4 DNA (±PDS) was partially rescued by wild-type and E466K hRev1. The E466A or Y470A mutants failed to suppress the PDS-induced increase in G4 mutation frequency. These findings have implications for the role of insert-2, a motif conserved in vertebrates but not yeast or plants, in Rev1-mediated suppression of mutagenesis during G4 replication.

scholarly journals Contribution of epoxyeicosatrienoic acids to flow-induced dilation in arteries of male ERα knockout mice: role of aromatase

2007 ◽  
Vol 293 (3) ◽  
pp. R1239-R1246 ◽  
Author(s):  
Dong Sun ◽  
Changdong Yan ◽  
Azita Jacobson ◽  
Houli Jiang ◽  
Mairead A. Carroll ◽  
...  
Keyword(s):  
Gas Chromatography Mass Spectrometry ◽  
Epoxyeicosatrienoic Acids ◽  
Epoxyeicosatrienoic Acid ◽  
Wild Type ◽  
Electrophysiological Technique ◽  
Isolated Arteries ◽  
Oxide Synthase ◽  
Interfering Rna ◽  
Endothelial Nitric Oxide

We studied the roles of estrogen receptors (ER) and aromatase in the mediation of flow-induced dilation (FID) in isolated arteries of male ERα-knockout (ERα-KO) and wild-type (WT) mice. FID was comparable between gracilis arteries of WT and ERα-KO mice. In WT arteries, inhibition of NO and prostaglandins eliminated FID. In ERα-KO arteries, Nω-nitro-l-arginine methyl ester (l-NAME) inhibited FID by ∼26%, whereas indomethacin inhibited dilations by ∼50%. The remaining portion of the dilation was abolished by additional administration of 6-(2-proparglyoxyphenyl)hexanoic acid (PPOH) or iberiotoxin, inhibitors of epoxyeicosatrienoic acid (EET) synthesis and large-conductance potassium channels, respectively. By using an electrophysiological technique, we found that, in the presence of 10 dyne/cm2 shear stress, perfusate passing through donor vessels isolated from gracilis muscle of ERα-KO mice subjected to l-NAME and indomethacin elicited smooth muscle hyperpolarization and a dilator response of endothelium-denuded detector vessels. These responses were prevented by the presence of iberiotoxin in detector or PPOH in donor vessels. Gas chromatography-mass spectrometry (GC-MS) analysis indicated a significant increase in arterial production of EETs in ERα-KO compared with WT mice. Western blot analysis showed a significantly reduced endothelial nitric oxide synthase expression but enhanced expressions of aromatase and ERβ in ERα-KO arteries. Treatment of ERα-KO arteries with specific aromatase short-interfering RNA for 72 h, knocked down the aromatase mRNA and protein associated with elimination of EET-mediation of FID. Thus, FID in male ERα-KO arteries is maintained via an endothelium-derived hyperpolarizing factor/EET-mediated mechanism compensating for reduced NO mediation due, at least in part, to estrogen aromatized from testosterone.

MO005HIGH LEVELS OF FIVE SPECIFIC FECAL METABOLITES IN IGA NEPHROPATHY PATIENTS SUPPORT THE HYPOTHESIS OF THE INTESTINAL-RENAL AXIS CONNECTION

2020 ◽  
Vol 35 (Supplement_3) ◽  
Author(s):  
Claudia Curci ◽  
Fabio Sallustio ◽  
Nada Chaoul ◽  
Angela Picerno ◽  
Gabriella Lauriero ◽  
...  
Keyword(s):  
B Cells ◽  
Iga Nephropathy ◽  
Solid Phase ◽  
Serum Levels ◽  
Intestinal Lumen ◽  
Gas Chromatography Mass Spectrometry ◽  
Control Group ◽  
Intestinal Immunity ◽  
Adaptive Immune Cells

Abstract Background and Aims The IgA nephropathy (IgAN) is the most frequent primitive glomerulonephritis. In the last years, the role of mucosal immunity in IgAN, together with that of the gut microbiota in the activation of innate and adaptive immune cells, has gained importance. Particularly interesting is the role of the microbiota and intestinal immunity in IgAN. BAFF and APRIL can be produced by the intestinal epithelium, in response to signals triggered by TLRs once activated by the commensal bacteria present in the intestinal lumen, representing the link between microbiota and intestinal immunity. To date, even if hypothesized, this relationship in IgAN patients has not been investigated. Here, we studied the intestinal-renal axis connections analyzing levels of BAFF, April and intestinal-activated B cells in IgAN patients. Method Serum and fecal samples were collected from 44 IgAN patients, 22 non-IgA glomerulonephritides (controls) and 22 healthy subjects (HS) with similar clinical features. BAFF and APRIL serum levels were measured by ELISA assay. Metabolomic analysis of fecal microbiome was performed using Biochrom 30 series amino acid analyzer and gas-chromatography mass spectrometry/solid-phase microextraction (GC-MS/SPME) analysis. B cell subsets were investigated by FACS. Results IgAN patients had increased serum levels of BAFF cytokine compared to the control group of patients with non-IgA glomerulonephritis and compared with HS (p<0.0001and p=0.012, respectively). We found that serum BAFF levels positively correlated with the levels of 24h-proteinuria in IgAN patients (r2 = 0.2269, p <0.001). We correlated serum BAFF levels with fecal concentration of 5 different metabolites of 30 IgAN patients, which were previously investigated for the fecal microbiota. These organic compounds had been found at significantly higher levels in the feces of IgAN patients compared to HS. Serum BAFF levels positively correlated with the levels of fecal metabolites: 4-(1,1,3,3-tetramethylbutyl) phenol (r2 = 0.2882, p = 0.0027), p-tert-butyl-phenol (r2 = 0.386, p = 0.0003), methyl neopentyl phthalic acid (r2 = 0.3491, p =0.0007), hexadecyl ester benzoic acid (r2 = 0.2832, p =0.003) and furanone A (r2 = 0.1743, p = 0.024). Serum levels of APRIL were significantly increased in IgAN patients respect to control groups (4.49 ± 0.54 vs 2.27 ± 1 ng/ml, p=0.0014). We found a correlation between APRIL and serum creatinine (r2 = 0.159, p =0.04) and eGFR (r2 = 0.2395, p =0.0082), while no correlation was found between APRIL and fecal metabolite levels in IgAN patients. In addition, we found that subjects with IgAN have a significantly higher proportion of circulating Bregs, Memory B cells and IgA secreting-plasmablasts activated at the intestinal level (CCR9+INTB7+) compared to HS. Conclusion The results of our study showed for the first time an important correlation of serum levels of BAFF with intestinal microbiota in patients with IgAN, confirming the hypothesis of the pathogenic role of intestinal mucosal hyperresponsiveness in the IgAN patients. The intestinal-renal axis plays a crucial role in Berger's glomerulonephritis, whose complex pathogenesis may contribute several factors as genetics, pathogens and food.

scholarly journals A Dominant-Negative fur Mutation in Bradyrhizobium japonicum

2004 ◽  
Vol 186 (5) ◽  
pp. 1409-1414 ◽  
Author(s):  
Heather P. Benson ◽  
Kristin LeVier ◽  
Mary Lou Guerinot
Keyword(s):  
Bradyrhizobium Japonicum ◽  
Iron Uptake ◽  
Outer Membrane Proteins ◽  
Dominant Negative ◽  
Ferric Uptake Regulator ◽  
Null Mutant ◽  
Nitrogen Fixing ◽  
Wild Type ◽  
Fur Protein

ABSTRACT In many bacteria, the ferric uptake regulator (Fur) protein plays a central role in the regulation of iron uptake genes. Because iron figures prominently in the agriculturally important symbiosis between soybean and its nitrogen-fixing endosymbiont Bradyrhizobium japonicum, we wanted to assess the role of Fur in the interaction. We identified a fur mutant by selecting for manganese resistance. Manganese interacts with the Fur protein and represses iron uptake genes. In the presence of high levels of manganese, bacteria with a wild-type copy of the fur gene repress iron uptake systems and starve for iron, whereas fur mutants fail to repress iron uptake systems and survive. The B. japonicum fur mutant, as expected, fails to repress iron-regulated outer membrane proteins in the presence of iron. Unexpectedly, a wild-type copy of the fur gene cannot complement the fur mutant. Expression of the fur mutant allele in wild-type cells leads to a fur phenotype. Unlike a B. japonicum fur-null mutant, the strain carrying the dominant-negative fur mutation is unable to form functional, nitrogen-fixing nodules on soybean, mung bean, or cowpea, suggesting a role for a Fur-regulated protein or proteins in the symbiosis.

scholarly journals Deletion of 1–43 amino acids in cardiac myosin essential light chain blunts length dependency of Ca2+ sensitivity and cross-bridge detachment kinetics

2013 ◽  
Vol 304 (2) ◽  
pp. H253-H259 ◽  
Author(s):  
John Jeshurun Michael ◽  
Sampath K. Gollapudi ◽  
Steven J. Ford ◽  
Katarzyna Kazmierczak ◽  
Danuta Szczesna-Cordary ◽  
...  
Keyword(s):  
Amino Acids ◽  
Light Chain ◽  
Sarcomere Length ◽  
Cardiac Myosin ◽  
Wild Type ◽  
Essential Light Chain ◽  
Cross Bridge ◽  
Maximal Activation ◽  
Cardiac Muscle Fibers

The role of cardiac myosin essential light chain (ELC) in the sarcomere length (SL) dependency of myofilament contractility is unknown. Therefore, mechanical and dynamic contractile properties were measured at SL 1.9 and 2.2 μm in cardiac muscle fibers from two groups of transgenic (Tg) mice: 1) Tg-wild-type (WT) mice that expressed WT human ventricular ELC and 2) Tg-Δ43 mice that expressed a mutant ELC lacking 1–43 amino acids. In agreement with previous studies, Ca2+-activated maximal tension decreased significantly in Tg-Δ43 fibers. pCa50 (−log10 [Ca2+]free required for half maximal activation) values at SL of 1.9 μm were 5.64 ± 0.02 and 5.70 ± 0.02 in Tg-WT and Tg-Δ43 fibers, respectively. pCa50 values at SL of 2.2 μm were 5.70 ± 0.01 and 5.71 ± 0.01 in Tg-WT and Tg-Δ43 fibers, respectively. The SL-mediated increase in the pCa50 value was statistically significant only in Tg-WT fibers ( P < 0.01), indicating that the SL dependency of myofilament Ca2+ sensitivity was blunted in Tg-Δ43 fibers. The SL dependency of cross-bridge (XB) detachment kinetics was also blunted in Tg-Δ43 fibers because the decrease in XB detachment kinetics was significant ( P < 0.001) only at SL 1.9 μm. Thus the increased XB dwell time at the short SL augments Ca2+ sensitivity at short SL and thus blunts SL-mediated increase in myofilament Ca2+ sensitivity. Our data suggest that the NH2-terminal extension of cardiac ELC not only augments the amplitude of force generation, but it also may play a role in mediating the SL dependency of XB detachment kinetics and myofilament Ca2+ sensitivity.

Role of the Sulfur-Containing Amino Acids in Protein-Induced Hypercalciuria in Men

1981 ◽  
Vol 111 (3) ◽  
pp. 545-552 ◽  
Author(s):  
Michael B. Zemel ◽  
Sally A. Schuette ◽  
Maren Hegsted ◽  
Hellen M. Linkswiler
Keyword(s):  
Amino Acids ◽  
Sulfur Containing

scholarly journals Role of Cytosolic Glyceraldehyde-3-Phosphate Dehydrogenase in Visceral Organ Infection by Leishmania donovani

2012 ◽  
Vol 12 (1) ◽  
pp. 70-77 ◽  
Author(s):  
Wen-Wei Zhang ◽  
Laura-Isobel McCall ◽  
Greg Matlashewski
Keyword(s):  
Leishmania Donovani ◽  
Null Mutant ◽  
Wild Type ◽  
Visceral Organ ◽  
Content Type ◽  
Visceral Organs ◽  
Deficient Medium ◽  
Visceral Disease ◽  
Organ Infection

ABSTRACTThe initial 7 steps of the glycolytic pathway from glucose to 3-phosphoglycerate are localized in the glycosomes inLeishmania, including step 6, catalyzed by the enzyme glyceraldehyde-3-phosphate dehydrogenase (GAPDH). InL. donovaniandL. mexicana, there exists a second GAPDH enzyme present in the cytosol that is absent inL. braziliensisand that has become a pseudogene inL. major.To investigate the role of the cytosolic GAPDH (cGAPDH), anL. donovanicGAPDH-null mutant was generated, and conversely, the functionalL. donovanicGAPDH was introduced intoL. majorand the resulting engineered parasites were characterized. TheL. donovanicGAPDH-null mutant was able to proliferate at the same rate as the wild-type parasite in glucose-deficient medium. However, in the presence of glucose, theL. donovanicGAPDH-null mutant consumed less glucose and proliferated more slowly than the wild-type parasite and displayed reduced infectivity in visceral organs of experimentally infected mice. This demonstrates that cGAPDH is functional inL. donovaniand is required for survival in visceral organs. Restoration of cGAPDH activity inL. major, in contrast, had an adverse effect onL. majorproliferation in glucose-containing medium, providing a possible explanation of why it has evolved into a pseudogene inL. major. This study indicates that there is a difference in glucose metabolism betweenL. donovaniandL. major, and this may represent an important factor in the ability ofL. donovanito cause visceral disease.

Arginine 595 is duplicated in patients with acute leukemias carrying internal tandem duplications of FLT3 and modulates its transforming potential

Blood ◽  
2007 ◽  
Vol 110 (2) ◽  
pp. 686-694 ◽  
Author(s):  
Sridhar Vempati ◽  
Carola Reindl ◽  
Seshu Kumar Kaza ◽  
Ruth Kern ◽  
Theodora Malamoussi ◽  
...  
Keyword(s):  
Amino Acids ◽  
Molecular Mechanism ◽  
Positive Charge ◽  
Critical Role ◽  
Heterogeneous Group ◽  
Wild Type ◽  
Acute Leukemias ◽  
Juxtamembrane Region ◽  
Tandem Duplications

Abstract FLT3–internal tandem duplications (FLT3-ITDs) comprise a heterogeneous group of mutations in patients with acute leukemias that are prognostically important. To characterize the mechanism of transformation by FLT3-ITDs, we sequenced the juxtamembrane region (JM) of FLT3 from 284 patients with acute leukemias. The length of FLT3-ITDs varied from 2 to 42 amino acids (AAs) with a median of 17 AAs. The analysis of duplicated AAs showed that in the majority of patients, the duplications localize between AAs 591 to 599 (YVDFREYEY). Arginine 595 (R595) within this region is duplicated in 77% of patients. Single duplication of R595 in FLT3 conferred factor-independent growth to Ba/F3 cells and activated STAT5. Moreover, deletion or substitution of the duplicated R595 in 2 FLT3-ITD constructs as well as the deletion of wild-type R595 in FLT3-ITD substantially reduced the transforming potential and STAT5 activation, pointing to a critical role of the positive charge of R595 in stabilizing the active confirmation of FLT3-ITDs. Deletion of R595 in FLT3-WT nearly abrogated the ligand-dependent activation of FLT3-WT. Our data provide important insights into the molecular mechanism of transformation by FLT3-ITDs and show that duplication of R595 is important for the leukemic potential of FLT3-ITDs.

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