Catabolism Of Compounds Research Articles

Host plants selection of Centranthera grandiflora Benth. and nontargeted metabolomics analysis of its parasitic and non-parasitic samples.

According to the previous investigation and research of our group, it was found that Centranthera grandiflora Benth. (C. grandiflora for short) might be a root hemiparasitic plant. The experiments of mixed sowing of C. grandiflora and 9 companion plants that might be hosts were conducted, and the growth, biological yield and other indexes were observed. The results showed that Cyperus iria L. was the best host for C. grandiflora, and when they were mixed sowed, C. grandiflora had a vigorous growth above ground and the haustoria connected obviously below ground, while C. grandiflora could achieve blossoming and fruiting in the same year. Next, nontargeted metabonomics analysis methods were utilized to clarify the differences in metabolites between parasitized and non-parasitized C. grandiflora. A total of 82 metabolites with significant differences were screened. The main upregulated differential metabolites of non-parasitized plants were for plant growth, while that of parasitized plants were functional compounds such as EPA. Out of 82 differential metabolites, 32 were annotated into 37 KEGG pathways. Analysis of the 37 pathways in combination with the differential metabolites showed that in addition to being involved in the synthesis pathway of iridoid terpenes, the up-regulated metabolites of parasitized plants were involved in the synthesis pathways of several functional components, while that of non-parasitic plants were involved in the subsequent catabolism of monoterpenoid compounds, as well as the metabolic pathways of nutrients synthesis and catabolism, energy generation, and phytohormone production required for plant growth.

Modulation of Gut Microbiota Composition and Microbial Phenolic Catabolism of Phenolic Compounds from Achillea millefolium L. and Origanum majorana L.

The impact of the nonbioaccessible fraction of two phenolic-rich extracts from Achillea millefolium L. (yarrow) and Origanum majorana L. (marjoram) on the modulation of the human gut microbiota was investigated in vitro. Microbial metabolism of the phenolic compounds was also addressed. In general, phenolic acids or O-glycosidic flavones quickly disappeared, in contrast to methoxy- or C-glycosidic flavonoids. This colonic metabolism yielded phloroglucinol, 3,4-dimethoxyphenylacetic acid, 3-(4-hydroxyphenyl)-propionic acid, and 4-hydroxybenzoic acid as the main metabolites of the microbial catabolism of rosmarinic acid or caffeoylquinic acids, among others. The 16S rRNA gene sequencing showed that the most promising modulatory effect was related to the increase in Bifidobacterium spp., Collinsella spp., Romboutsia, and Akkermansia muciniphila for both plant extracts, along with Blautia spp. and Dialister for yarrow extract. This beneficial modulation was accompanied by the increase in butyric acid production, highlighting the potential prebiotic-like effect on the gut microbiota of these two previously unstudied edible plants.

A-132 Next generation ammonia reagent with improved reagent composition and assay performance

Abstract Background Ammonia is produced by catabolism of protein and other compounds which contain nitrogen. Elevated ammonia levels are toxic for the central nervous system. High plasma ammonia is a prognostic factor for hepatic and kidney disease or inherited metabolic disorders in urea cycle metabolism. The reliable and accurate quantification of ammonia is influenced by assay, reagent, and sample management. Current commercially available GLDH enzyme-based ammonia assay reagents experience high bias between matched Lithium Heparin and K2-EDTA samples, poor accuracy, imprecision at the low end, large HIL (hemolysis, icterus and lipemia) interferences and shorter shelf life. To improve upon the listed deficiencies, we developed an improved GLDH based ammonia assay in a two-part format with improved reagent composition. Methods Ammonia reagent in 2-part format R1 and R2 were assessed for accuracy, precision, interference by HIL reportable range, sensitivity (LoB, LoD, LoQ), shelf life, matched matrix comparison (Lithium Heparin vs K2-EDTA) and method comparison. All testing were performed using Li Heparin plasma samples in Beckman DxC700AU analyzer. Accuracy was tested using Verichem ammonia standards which are ACS ammonia standard material. Twenty-day precision studies were performed using three levels of ammonia concentrations using Bio-Rad Liquichek Ammonia controls and plasma samples. Interference was tested in two ammonia concentrations (40-50 µmol/L) and (200-250 µmol/L) using commercially available spiking material for clinical chemistry assays such as conjugated and unconjugated bilirubin, Intralipid and in-house prepared hemolysate. Infinity Ammonia Reagent on Beckman Coulter AU Chemistry Analyzers was used for method comparison studies Results Next generation ammonia showed good accuracy with Verichem ammonia standards and acceptable within-run and total precision. Studies showed significant improvement in sensitivity and longer shelf life (>18 months). Next generation ammonia is less affected by interferences from icterus (100 mg/dL), lipemia (1000 mg/dL intralipid) and hemolysis (100 mg/dL). Comparison studies show no significant bias between match Lithium Heparin and K2-EDTA matched samples. Conclusions Next Generation Ammonia reagent showed very good overall performance required for reliable and accurate quantification of ammonia in human plasma sample.

ADVANCEMENTS IN UNDERSTANDING THE MOLECULAR MECHANISMS REGULATING URIC ACID METABOLISM IN THE INTESTINE

This review provides contemporary insights into the direct and indirect pathogenetic connections between purine compound metabolism and biochemical processes within the cells of the gastrointestinal system. A thorough analysis of recent publications from 2000 to 2024, sourced from databases including Scopus, PubMed, eLIIBRARY, and Google Scholar, was conducted. Uric acid serves as the end product of purine-containing compound catabolism. Its concentration is intricately regulated through the collaboration of the kidneys and gastrointestinal organs, namely the small intestine and liver. Gout, a chronic condition, emerges from the interplay between molecular genetic factors and external influences. Elevated levels of urates in the blood serum (hyperuricemia) and the deposition of sodium urate crystals in organs and tissues set off a cascade of inflammatory and fibrotic processes within mucosal, smooth muscle, parenchymal, and endothelial cells, including those within the gastrointestinal tract. Normally, a person excretes about 1.5 g of uric acid per day. Under physiological conditions, two-thirds of uric acid is excreted from the body by the kidneys, one-third through the intestines, and a small part is excreted with bile. The hypothesis that links the pathogenesis of hyperuricemia with “renal overload” suggests that the disease may develop as a result of impaired renal excretion with insufficient elimination of uric acid through the intestines. Part of uric acid transport systems actively works in hepatocytes and enterocytes, which determines its formation and clearance. Uric acid transporter proteins are divided into two categories: urate reabsorption transporters and urate excretion transporters, their expression is regulated by transcription factors, hormones and metabolites of intestinal microflora. The influence of intestinal microbiota on uric acid metabolism is related to its participation in purine metabolism, decomposition and elimination of uric acid with metabolites of intestinal flora and inhibition of gouty inflammation and is evaluated as a new therapeutic potential in gout and hyperuricemia, which allows to avoid kidney damage and urolithiasis.

Analyses of long-term fungal degradation of spruce bark reveals varying potential for catabolism of polysaccharides and extractive compounds

The bark represents the outer protective layer of trees. It contains high concentrations of antimicrobial extractives, in addition to regular wood polymers. It represents a huge underutilized side stream in forestry, but biotechnological valorization is hampered by a lack of knowledge on microbial bark degradation. Many fungi are efficient lignocellulose degraders, and here, spruce bark degradation by five species, Dichomitus squalens, Rhodonia placenta, Penicillium crustosum, Trichoderma sp. B1, and Trichoderma reesei, was mapped, by continuously analyzing chemical changes in the bark over six months. The study reveals how fungi from different phyla degrade bark using diverse strategies, regarding both wood polymers and extractives, where toxic resin acids were degraded by Basidiomycetes but unmodified/tolerated by Ascomycetes. Proteome analyses of the white-rot D. squalens revealed several proteins, with both known and unknown functions, that were specifically upregulated during growth on bark. This knowledge can accelerate improved utilization of an abundant renewable resource.

Resting cell formation in the marine diatom Thalassiosira pseudonana.

Resting cells represent a survival strategy employed by diatoms to endure prolonged periods of unfavourable conditions. In the oceans, many diatoms sink at the end of their blooming season and therefore need to endure cold and dark conditions in the deeper layers of the water column. How they survive these conditions is largely unknown. We conducted an integrative analysis encompassing methods from histology, physiology, biochemistry, and genetics to reveal the biological mechanism of resting-cell formation in the model diatom Thalassiosira pseudonana. Resting-cell formation was triggered by a decrease in light and temperature with subsequent catabolism of storage compounds. Resting cells were characterised by an acidic and viscous cytoplasm and altered morphology of the chloroplast ultrastructure. The formation of resting cells in T. pseudonana is an energy demanding process required for a biophysical alteration of the cytosol and chloroplasts to endure the unfavourable conditions of the deeper ocean as photosynthetic organisms. However, most resting cells (> 90%) germinate upon return to favorable growth conditions.

Inhibition of the Progression of Chronic Kidney Disease With Hyperuricemia

The final product of the catabolism of purine compounds in humans is uric acid (UA), which is a weak organic acid, over 98% of which is ionized into monosodium urate. UA is excreted by the kidneys, approximately 80-99% is reabsorbed in the proximal tubules of the kidneys. About 20% of UA is excreted through the intestine, where it is destroyed by microflora to carbon dioxide and water. The reference value of UA in blood plasma is 6.5-7 mg/dl in men and 6–6.5 mg/dl in women. The content of UA in the range of 360-400 μmol/l or 6-6.8 mg / dl increases the risk of crystallization under physiological conditions, and regardless of gender. UA levels greater than 7.0 mg/dl are associated with an increased risk of developing gout or nephrolithiasis. Hyperuricemia may occur due to increased production and / or decreased renal excretion of UA. Hyperuricemia is high in the general population and is associated with the development and progression of chronic kidney disease (CKD). Currently, allopurinol and febuxostat are used to correct hyperuricemia. The use of allopurinol should begin with a low dose (50-100 mg/day) and gradually titrate until the target level of UA in the blood is reached or until it is reached to the maximum. If necessary, the dose of allopurinol is increased by 100 mg every 2–4 weeks until the target serum UA level is reached. According to EULAR's recommendations for the treatment of gout, if the target level of UA cannot be achieved with an adequate dose of allopurinol, it should be replaced with febuxostat or uricosuric or a combination of febucostat with uricosuric. Febuxostat is also indicated for allopurinol intolerance. Febuxostat in doses of 80 and 120 mg/day was more effective than allopurinol at a dose of 300 mg/day. With CKD with mild or moderate renal failure, as well as in the elderly, it is not necessary to adjust the dose of febuxostat. The likelihood of reaching the target level of UA in the blood with reduced kidney function is higher in febuxostat. If the patient does not have serious cardiovascular diseases, the patient can be transferred to febuxostat, starting with a dose of 40 mg/day, and gradually titrated, especially in the case of CKD.

Bringing up to date the toolkit for the catabolism of aromatic compounds in fungi: The unexpected 1,2,3,5-tetrahydroxybenzene central pathway.

Saprophytic fungi are able to catabolize many plant-derived aromatics, including, for example, gallate. The catabolism of gallate in fungi is assumed to depend on the five main central pathways, i.e., of the central intermediates' catechol, protocatechuate, hydroxyquinol, homogentisate and gentisate, but a definitive demonstration is lacking. To shed light on this process, we analysed the transcriptional reprogramming of the growth of Aspergillus terreus on gallate compared with acetate as the control condition. Surprisingly, the results revealed that the five main central pathways did not exhibit significant positive regulation. Instead, an in-depth analysis identified four highly expressed and upregulated genes that are part of a conserved gene cluster found in numerous species of fungi, though not in Aspergilli. The cluster comprises a monooxygenase gene and a fumarylacetoacetate hydrolase-like gene, which are recognized as key components of catabolic pathways responsible for aromatic compound degradation. The other two genes encode proteins with no reported enzymatic activities. Through functional analyses of gene deletion mutants in Aspergillus nidulans, the conserved short protein with no known domains could be linked to the conversion of the novel metabolite 5-hydroxydienelatone, whereas the DUF3500 gene likely encodes a ring-cleavage enzyme for 1,2,3,5-tetrahydroxybenzene. These significant findings establish the existence of a new 1,2,3,5-tetrahydroxybenzene central pathway for the catabolism of gallate and related compounds (e.g. 2,4,6-trihydroxybenzoate) in numerous fungi where this catabolic gene cluster was observed.

Valorization of lignin-derived compounds into poly(3-hydroxybutyrate-co-3-hydroxyvalerate) by engineered Halomonas sp. Y3

Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) is a biopolyester with great potential, but its high production cost via the propionate-dependent pathway has hindered its development. Herein, we engineer Halomonas sp. Y3 to achieve efficient conversion of various LDCs into PHBV without propionate supplement. Initially, we successfully achieve PHBV production without propionate supplement by overexpressing threonine synthesis. The resulting biopolyester exhibits a 3 HV proportion of up to 7.89 mol%, comparable to commercial PHBV (8 mol%) available from Sigma Aldrich (403105). To further enhance PHBV production, we rationally design the reconstruction of aromatic compound catabolism. The engineered strain Y3_18 efficiently assimilates all LDCs containing syringyl (S), guaiacyl (G), and p-hydroxyphenyl-type (H) units. From 1 g/L of S-, G-, and H-type LDCs, Y3_18 produces PHBV at levels of 449 mg/L, 488 mg/L, and 716 mg/L, respectively, with yields of 44.9 % (g/g), 48.8 % (g/g), and 71.6 % (g/g). Moreover, to improve PHBV yield from lignin, we integrate laccase-secretion and PHBV production modules. This integration leads to the accumulation of 425.84 mg/L of PHBV with a yield of 21.29 % (g/g) and a 3 HV proportion of 6.38 mol%. By harnessing the capabilities of Halomonas sp. Y3, we demonstrate an efficient and sustainable approach for PHBV production from a variety of LDCs.

Exogenous c-di-GMP inhibited the biofilm formation of Vibrio splendidus.

Vibrio splendidus, a gram-negative bacterium that is ubiquitously present in marine environments, has been increasingly deemed an important opportunistic pathogen of marine animals. In this study, the biofilm formation of V. splendidus was quantitatively determined and morphologically characterized. Three stages of biofilm formation, including adhesion, aggregation and maturation were observed in the biofilm formed by V. splendidus. The inhibitory effect of exogenous bis (3',5')-cyclic dimeric guanosine monophosphate (c-di-GMP) on the biofilm formation from the scratch and preformed established biofilms of V. splendidus was determined. When 200μmol/L c-di-GMP was added, the quantity of biofilm decreased by 88.1% or 66.7% under the two conditions. To explore the preliminary mechanism of exogenous c-di-GMP on the biofilm formed by V. splendidus, proteomic analysis was performed. GO enrichment analysis showed that exogenous c-di-GMP upregulated biological processes, including the tricarboxylic acid cycle, oxidation‒reduction reactions and organonitrogen compound catabolism and significantly downregulated tRNA threonylcarbamoyladenosine modification, protein dephosphorylation, and lactate transmembrane transporter activity. Sequence-specific DNA binding activity was the most markedly downregulated molecular function. KEGG analysis showed that the valine, leucine and isoleucine degradation pathway was the most enriched pathway, followed by nitrogen metabolism, among the 20 upregulated pathways. Among the downregulated pathways, a nonribosomal peptide structure pathway and the streptomycine, polyketide sugar unit, acarbose and validamycin biosynthesis pathways were significantly enriched. Our present study provides basic data for the biofilm formation of V. splendidus and the preliminary inhibitory mechanism of exogenous c-di-GMP on the biofilm formation of V. splendidus.

Metabolic profiles and fingerprints for the investigation of the influence of nitisinone on the metabolism of the yeast Saccharomyces cerevisiae

Nitisinone (2-(2-nitro-4-trifluoromethylbenzoyl)-1,3-cyclohexanedione, NTBC) is considered a potentially effective drug for the treatment of various metabolic diseases associated with disorders of l-tyrosine metabolism however, side-effects impede its widespread use. This work aimed to broaden the knowledge of the influence of NTBC and its metabolites 2-amino-4-(trifluoromethyl)benzoic acid (ATFA), 2-nitro-4-(trifluoromethyl)benzoic acid (NTFA), and cyclohexane-1,3-dione (CHD) on the catabolism of l-tyrosine and other endogenous compounds in Saccharomyces cerevisiae. Based on a targeted analysis performed by LC–ESI–MS/MS, based on multiple reaction monitoring, it was found that the dissipation kinetics of the parent compound and its metabolites are compatible with a first-order reaction mechanism. Moreover, it has been proven that formed NTBC metabolites, such as CHD, cause a decrease in l-tyrosine, l-tryptophan, and l-phenylalanine concentrations by about 34%, 59% and 51%, respectively, compared to the untreated model organism. The overall changes in the metabolism of yeast exposed to NTBC or its derivatives were evaluated by non-targeted analysis via LC–ESI–MS/MS in the ion trap scanning mode. Based on principal components analysis, a statistically significant similarity between metabolic responses of yeast treated with ATFA or NTFA was observed. These findings facilitate further studies investigating the influence of NTBC on the human body and the mechanism of its action.

Integrative omics analyses of the ligninolytic Rhodosporidium fluviale LM-2 disclose catabolic pathways for biobased chemical production

BackgroundLignin is an attractive alternative for producing biobased chemicals. It is the second major component of the plant cell wall and is an abundant natural source of aromatic compounds. Lignin degradation using microbial oxidative enzymes that depolymerize lignin and catabolize aromatic compounds into central metabolic intermediates is a promising strategy for lignin valorization. However, the intrinsic heterogeneity and recalcitrance of lignin severely hinder its biocatalytic conversion. In this context, examining microbial degradation systems can provide a fundamental understanding of the pathways and enzymes that are useful for lignin conversion into biotechnologically relevant compounds.ResultsLignin-degrading catabolism of a novel Rhodosporidium fluviale strain LM-2 was characterized using multi-omic strategies. This strain was previously isolated from a ligninolytic microbial consortium and presents a set of enzymes related to lignin depolymerization and aromatic compound catabolism. Furthermore, two catabolic routes for producing 4-vinyl guaiacol and vanillin were identified in R. fluviale LM-2.ConclusionsThe multi-omic analysis of R. fluviale LM-2, the first for this species, elucidated a repertoire of genes, transcripts, and secreted proteins involved in lignin degradation. This study expands the understanding of ligninolytic metabolism in a non-conventional yeast, which has the potential for future genetic manipulation. Moreover, this work unveiled critical pathways and enzymes that can be exported to other systems, including model organisms, for lignin valorization.

Transcriptome analysis of halophyte Nitraria tangutorum reveals multiple mechanisms to enhance salt resistance

As a typical halophyte, Nitraria tangutorum Bobr. has attracted the interest of many researchers with the excellent salt tolerance. Elucidation of the mechanism of N. tangutorum salinity tolerance will facilitate the genetic improvement of productive plants faced with salinity. To reveal the molecular response to gradually accumulated salt stress in N. tangutorum, RNA-sequencing and analysis of gradually accumulated NaCl treated samples and control samples were performed, and a total of 1419 differentially expressed genes were identified, including 949 down-regulated genes and 470 up-regulated genes. Detailed analysis uncovered that the catabolism of organic compounds mainly based on oxidative phosphorylation genes was up-regulated. Additionally, various antioxidant genes, especially anthocyanin-related genes, were found to help N. tangutorum remove reactive oxygen species. Moreover, the Mitogen activated protein kinase signaling pathway and other signaling pathways co-regulated various salt tolerance activities. Additionally, intracellular ion homeostasis was maintained via regulation of osmotic regulator-related genes, cutin-related genes, and cell elongation-related genes to retain cellular water and reduce ion concentration. In particularly, simultaneous up-regulation in cytoskeleton-related genes, cell wall-related genes, and auxin-related genes, provided evidence of important role of cell expansion in plant salt tolerance. In conclusion, complex regulatory mechanisms modulated by multiple genes might contribute to the salt tolerance by N. tangutorum.

Discovery, characterization, and metabolic engineering of Rieske non-heme iron monooxygenases for guaiacol O-demethylation

Aryl- O -demethylation is a common rate-limiting step in the catabolism of lignin-related compounds, including guaiacol. Here we used randomly barcoded transposon insertion sequencing (RB-TnSeq) in the bacterium Novosphingobium aromaticivorans to identify a Rieske-type guaiacol O -demethylase, GdmA. Similarity searches identified GdmA homologs in other bacteria, along with candidate reductase partners, denoted GdmB. GdmAB combinations were biochemically characterized for activity with several lignin-related substrates. Structural and sequence comparisons of vanillate- and guaiacol-specific O- demethylase active sites revealed conserved hallmarks of substrate specificity. GdmAB combinations were also evaluated in Pseudomonas putida KT2440, which does not natively utilize guaiacol. GdmAB from Cupriavidus necator N-1 demonstrated the highest rate of guaiacol turnover in vitro and in engineered P. putida strains and notably higher catalytic efficiency than a cytochrome P450 system (GcoAB) and the vanillate Rieske-type O -demethylase from P. putida (VanAB). The GdmAB O -demethylases described here expand the suite of options for microbial conversion of a model lignin-derived substrate. • A Rieske monooxygenase, GdmA, demethylates guaiacol in N. aromaticivorans DSM12444 • GdmA homologs and associated GdmB reductases display differences in specific activity • Structural comparison of O -demethylase active sites illuminates substrate specificity • Expression of GdmAB in engineered P. putida KT2440 enables growth on guaiacol Lignin is an abundant heterogenous component of plant cell walls, and its valorization is key to enable a profitable and sustainable global biofuels industry. A major challenge to convert lignin to chemicals is overcoming the inherent heterogeneity of deconstructed lignin polymers, and in recent years, microbial conversion has emerged as a means to produce single target compounds from mixtures of aromatic compounds. This work reports the discovery, characterization, and engineering of an enzyme system that can efficiently demethylate a lignin-related compound, 2-methoxy-phenol (commonly known as guaiacol). Aromatic O -demethylation is a common rate-limiting step in aromatic catabolic pathways and, thus, a prime target for discovery, engineering, and evolution of new enzymes. Going forward, biocatalysis development like that reported here may ultimately enable an integrated chemocatalytic and biocatalytic valorization approach for a major component of plant cell walls. Bacterial catabolism of lignin-related aromatic compounds is often limited by aryl- O -demethylation. This study identified a Rieske-type monooxygenase, GdmA, that catalyzes O- demethylation of guaiacol in Novosphingobium aromaticivorans. Detailed characterization of this enzyme, along with GdmA homologs and associated reductase partners (GdmB), identified differences in specific activity and substrate preference. Heterologous expression of GdmAB in Pseudomonas putida enabled growth on guaiacol. GdmAB O -demethylases expand the suite of options for microbial conversion of a model lignin-derived substrate.

In Vitro Faecal Fermentation of Monomeric and Oligomeric Flavan-3-ols: Catabolic Pathways and Stoichiometry.

The study evaluates the influence of flavan-3-ol structure on the production of phenolic catabolites, principally phenyl-γ-valerolactones (PVLs), and phenylvaleric acids (PVAs). A set of 12 monomeric flavan-3-ols and proanthocyanidins (degree of polymerization (DP) of 2-5), are fermented in vitro for 24 h using human faecal microbiota, and catabolism is analyzed by UHPLC-ESI-MS/MS. Up to 32 catabolites strictly related to microbial catabolism of parent compounds are detected. (+)-Catechin and (-)-epicatechin have the highest molar mass recoveries, expressed as a percentage with respect to the incubated concentration (75µmol L-1 ) of the parent compound, for total PVLs and PVAs, both at 5 h (about 20%) and 24 h (about 40%) of faecal incubation. Only A-type dimer and B-type procyanidins underwent the ring fission step, and no differences are found in total PVL and PVA production (≃1.5% and 6.0% at 5 and 24 h faecal incubation, respectively) despite the different DPs. The flavan-3-ol structure strongly affects the colonic catabolism of the native compounds, influencing the profile of PVLs and PVAs produced in vitro. This study opens new perspectives to further elucidate the colonic fate of oligomeric flavan-3-ols and their availability in producing bioactive catabolites.

Comprehensive silk gland multi-omics comparison illuminates two alternative mechanisms in silkworm heterosis.

Heterosis is a common phenomenon in plants and animals with diverse underlying mechanisms. Here, we applied two widely used silkworm hybrid systems and performed multi-omics analysis to identify possible intrinsic associations between different hybrid strategies and epigenetic mechanisms with silkworm heterosis. We found significant differences in the silk gland transcriptomic landscape between the two systems, including differentially expressed genes and expression patterns in the hybrid offspring compared to their parents. In the quaternary hybrid system, hybrid vigor was primarily due to up-regulated genes and the parent-dominant up-regulated expression pattern, involving multiple transport processes, cellular nitrogen compound catabolism, glucose metabolism, and tricarboxylic acid cycle. In the binary system, hybrid vigor was mainly due to the down-regulated genes and transgressively down-regulated expression pattern, mainly involving basic nitrogen synthesis metabolism and body function. We also demonstrated that DNA methylation may affect hybrid vigor by regulating the expression of several heterosis-related genes. Thus, this study revealed two alternative mechanisms that may contribute to silkworm heterosis, both of which facilitate the efficient utilization of energy and nitrogen for silk production.

Vitamin characterization and volatile composition of camu-camu (Myrciaria dubia (HBK) McVaugh, Myrtaceae) at different maturation stages

During the process of fruit development there is synthesis and catabolism of compounds that culminate with the specific characteristics of each species, such as changes in color, size, acidity, vitamins content and volatile composition. In the present study was evaluated during the development of camu-camu (Myrciaria dubia (HBK) McVaugh, Myrtaceae) the contents of pH, At, SS (ºBrix), Vitamin C, polyphenols, (L *, a * and b *) coloration and volatile composition using the HSPME-CGMS technique, at different stages of development. During development, an increase in the ºbrix variable was detected (6.92 to 9.02), and a decrease in the levels of vitamin C 1150 mg/100 g and total polyphenols 1280mg / 100g. Regarding the volatile composition, there was a difference of compounds according to the stage of development analyzed. Among the identified components, terpenes were the major class of compounds at all stages of maturation (p<0.05).

Xanthomonas transcriptome inside cauliflower hydathodes reveals bacterial virulence strategies and physiological adaptations at early infection stages.

Xanthomonas campestris pv. campestris (Xcc) is a seed‐transmitted vascular pathogen causing black rot disease on cultivated and wild Brassicaceae. Xcc enters the plant tissues preferentially via hydathodes, which are organs localized at leaf margins. To decipher both physiological and virulence strategies deployed by Xcc during early stages of infection, the transcriptomic profile of Xcc was analysed 3 days after entry into cauliflower hydathodes. Despite the absence of visible plant tissue alterations and despite a biotrophic lifestyle, 18% of Xcc genes were differentially expressed, including a striking repression of chemotaxis and motility functions. The Xcc full repertoire of virulence factors had not yet been activated but the expression of the HrpG regulon composed of 95 genes, including genes coding for the type III secretion machinery important for suppression of plant immunity, was induced. The expression of genes involved in metabolic adaptations such as catabolism of plant compounds, transport functions, sulphur and phosphate metabolism was upregulated while limited stress responses were observed 3 days postinfection. We confirmed experimentally that high‐affinity phosphate transport is needed for bacterial fitness inside hydathodes. This analysis provides information about the nutritional and stress status of bacteria during the early biotrophic infection stages and helps to decipher the adaptive strategy of Xcc to the hydathode environment.

Master regulator NtrC controls the utilization of alternative nitrogen sources in Pseudomonas stutzeri A1501

Pseudomonas stutzeri A1501 is a model strain used to study associative nitrogen fixation, and it possesses the nitrogen regulatory NtrC protein in the core genome. Nitrogen sources represent one of the important factors affecting the efficiency of biological nitrogen fixation in the natural environment. However, the regulation of NtrC during nitrogen metabolism in P. stutzeri A1501 has not been clarified. In this work, a phenotypic analysis of the ntrC mutant characterized the roles of NtrC in nitrogen metabolism and the oxidative stress response of P. stutzeri A1501. To systematically identify NtrC-controlled gene expression, RNA-seq was performed to further analyse the gene expression differences between the wild-type strain and the ∆ntrC mutant under nitrogen fixation conditions. A total of 1431 genes were found to be significantly altered by ntrC deletion, among which 147 associative genes had NtrC-binding sites, and the pathways for nitrogen fixation regulation, nitrogenous compound acquisition and catabolism and nitrate assimilation were discussed. Furthermore, the oxidative stress-related gene (katB), which was upregulated by ntrC deletion, was suggested to be a potential target gene of NtrC, thus highlighting the importance of NtrC in nitrogenase protection against oxygen damage. Based on these findings, we propose that NtrC is a high-ranking element in the regulatory network of P. stutzeri A1501 that controls a variety of nitrogen metabolic and oxidative stress responsive traits required for adaptation to complex rhizosphere environments.

Nutritional and end-use perspectives of sprouted grains: A comprehensive review.

Scientific literature is evident that the germinated seeds possess a promising potential for essential nutrients, flavors, and textural attributes over nongerminated grain. In recent decades, sprouting has also been investigated as a potential green food engineering technique to boost the nutritive profile of grains. Sprouting grains have multifold applications in different fields such as baking, pharmaceutical, and cosmetic industries. During sprouting, shifting of molecular structures to macroscopic takes place. Sprouting reactivates the grain metabolism which leads to the catabolism and degradation of antinutrient and macronutrient compounds. These modifications have an effect on human health and on the nutritional content of the foodstuffs. Sprouting grains have high bioactivity against diabetes and cancer. Germination is also an outstanding green food development technique to increase the seed nutritive profile in terms of quality. The present review focuses on the sprouting of grains, changes in nutritional profile, and the technological exploration of sprouted grains.