Search Results (56)

Crop rotation and microbial driving force significantly influence soil phosphorus (P) bioavailability and crop yield. However, differences in underlying microbial mechanisms in rotations remain unclear. We examined rice yield, P uptake, soil and microbial P contents, enzyme activity, and P functional genes over six years (2016–2022) to elucidate microbial mechanisms driving rice yield in rice–wheat (RW) and rice–oilseed rape (RO) rotations. RO significantly increased rice yield and plant P uptake by 9.17% and 20.70%, respectively, compared to RW. Soil total (TP) and available (AP) P contents were significantly lower (4.83% and 18.31%, respectively) under RO than RW, whereas microbial biomass phosphorus (MBP) and acid phosphatase activity (EP) were greater (39.40% and 128.45%, respectively). PICRUSt2 results revealed that RO increased phoA phoB (alkaline phosphatase), phnX (phosphonoacetaldehyde hydrolase [EC:3.11.1.1]), gcd (Quinoprotein glucose dehydrogenase [EC:1.1.5.2]), and ppaC (manganese-dependent inorganic pyrophosphatase) and decreased phnD (phosphonate transport system substrate-binding protein), ugpE (sn-glycerol 3-phosphate transport system permease protein), ugpA (sn-glycerol 3-phosphate transport system permease protein), and phnO ((aminoalkyl)phosphonate N-acetyltransferase [EC:2.3.1.280]) abundance. Random forest analysis showed that ppaC, phnD, gcd, and phnX were important for rice yield and plant P uptake. Partial least squares analysis revealed that RO indirectly increased rice yield by influencing MBP and affecting plant P uptake through P functional genes. Overall, RO improves rice yield and P bioavailability by altering P functional genes (ppaC, phnD, gcd, and phnX), providing new perspectives on crop–microorganism interactions and resource use efficiency. Full article

Background/Objectives: Blast-induced traumatic ocular injuries (bTOI) pose a significant risk to military and civilian populations, often leading to visual impairment or blindness. Retina, the innermost layer of ocular tissue consisting of photoreceptor and glial cells, is highly susceptible to blast injuries. Despite its prevalence, the molecular mechanisms underlying retinal damage following bTOI remain poorly understood, hindering the development of targeted therapies. Melatonin, a neuroprotective indoleamine with antioxidant, anti-inflammatory, and circadian regulatory properties, is synthesized in the retina and plays a crucial role in retinal health. Similarly, retina-specific genes, such as Rhodopsin, Melanopsin, and RPE65, are essential for photoreceptor function, visual signaling, and the visual cycle. However, their responses to blast exposure have not been thoroughly investigated. Methods: In this study, we utilized a ferret model of bTOI to evaluate the temporal expression of melatonin-synthesizing enzymes, such as tryptophan hydroxylase 1 and 2 (TPH1 and TPH2), Aralkylamine N-acetyltransferase (AANAT), and Acetylserotonin-O-methyltransferase (ASMT), and retina-specific genes (Rhodopsin, Melanopsin) and retinal pigment epithelium-specific 65 kDa protein (RPE65) at 4 h, 24 h, 7 days, and 28 days post-blast. Ferrets were exposed to tightly coupled blast overpressure waves using an advanced blast simulator, and retinal tissues were collected for quantitative polymerase chain reaction (qPCR) analysis. Results: The results revealed dynamic and multiphasic transcriptional responses. TPH1 and TPH2 exhibited significant upregulation at 24 h, followed by downregulation at 28 days, indicating blast-induced dysregulation of tryptophan metabolism, including melatonin synthesis. Similarly, AANAT and ASMT showed acute downregulation post-blast, with late-phase disruptions. Rhodopsin expression increased at 24 h but declined at 28 days, while Melanopsin and RPE65 demonstrated early upregulation followed by downregulation, reflecting potential disruptions in circadian regulation and the visual cycle. Conclusions: These findings highlight the complex regulatory mechanisms underlying retinal responses to bTOI, involving neuroinflammation, oxidative stress, and disruptions in melatonin synthesis and photoreceptor cell functions. The results emphasize the therapeutic potential of melatonin in mitigating retinal damage and preserving visual function. Full article

Geckos are often considered to be reservoirs of zoonotic pathogens. This study was conducted to describe the prevalence and characteristics of pathogens isolated from fecal samples of crested geckos in South Korea. A total of 76 fecal samples were collected from 76 domesticated crested geckos in independent captivity. To determine bacterial profiles, matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS), the disk diffusion method, PCR and direct sequencing, and the Kauffmann–White scheme for serotyping Salmonella species were performed. A total of 107 Gram-negative isolates were identified as belonging to 50 Citrobacter species, 33 Salmonella enterica subsp., 8 Serratia marcescens, 8 Klebsiella species, 3 Morganella morganii, 2 Enterobacter cloacae, 2 Pseudomonas aeruginosa, and 1 Acinetobacter species. Most of the isolates were susceptible to antibiotics tested in this study. The chloramphenicol acetyltransferase (cat) gene was detected in one M. morganii isolate, and the class C beta-lactamase (AZECL-14) gene was detected in one E. cloacae. The most prevalent somatic (O) antigens of the groups were C (n = 23) and D (n = 7), and 8 different serotypes were identified among the 33 Salmonella enterica subsp. isolates. Five of eight Salmonella serotypes have not been previously reported among clinical isolates in South Korea. Our results reveal that enteric bacteria have not been shared between crested geckos and humans, at least in South Korea. Full article

Carnitine O-acetyltransferase (CRAT) is a key mitochondrial enzyme involved in maintaining metabolic homeostasis by mediating the reversible transfer of acetyl groups between acetyl-CoA and carnitine. This enzymatic activity ensures the optimal functioning of mitochondrial carbon flux by preventing acetyl-CoA accumulation, buffering metabolic flexibility, and regulating the balance between fatty acid and glucose oxidation. CRAT’s interplay with the mitochondrial carnitine shuttle, involving carnitine palmitoyltransferases (CPT1 and CPT2) and the carnitine carrier (SLC25A20), underscores its critical role in energy metabolism. Emerging evidence highlights the structural and functional diversity of CRAT and structurally related acetyltransferases across cellular compartments, illustrating their coordinated role in lipid metabolism, amino acid catabolism, and mitochondrial bioenergetics. Moreover, the structural insights into CRAT have paved the way for understanding its regulation and identifying potential modulators with therapeutic applications for diseases such as diabetes, mitochondrial disorders, and cancer. This review examines CRAT’s structural and functional aspects, its relationships with carnitine shuttle members and other carnitine acyltransferases, and its broader role in metabolic health and disease. The potential for targeting CRAT and its associated pathways offers promising avenues for therapeutic interventions aimed at restoring metabolic equilibrium and addressing metabolic dysfunction in disease states. Full article

Cysteine is an essential amino acid for sustaining life, including protein synthesis, and serves as a precursor for antioxidant glutathione. Pathogenic bacteria synthesize cysteine via a two-step enzymatic process using serine as the starting material. The first step is catalyzed by serine acetyltransferase, also known as CysE, and the second by O-acetylserine sulfhydrylase (OASS), referred to as CysK or CysM. This cysteine biosynthetic pathway in bacteria differs significantly from that in mammals, making it an attractive target for the development of novel antibacterial agents. In this study, we aimed to identify OASS inhibitors. To achieve this, a high-throughput screening system was developed to analyze compounds capable of inhibiting CysK/CysM activity. Screening 168,640 compounds from a chemical library revealed that gliotoxin, a fungal metabolite, strongly inhibits both CysK and CysM. Furthermore, gliotoxin significantly suppressed the growth of Salmonella enterica serovar Typhimurium, a Gram-negative bacterium, under cystine-deficient conditions. Gliotoxin possesses a unique disulfide structure classified as epipolythiodioxopiperazine. To date, no studies have reported OASS inhibition by compounds with this structural motif, highlighting its potential for future structural optimization. The screening system developed in this study is expected to accelerate the discovery of functional CysK/CysM inhibitors, providing a foundation for novel antibacterial strategies. Full article

Alzheimer’s disease (AD) is a representative neurodegenerative disease characterized by the structural and functional degeneration of neurons. The present study investigated the neuroprotective effect of Ixeris dentata (ID) extract on trimethyltin (TMT)-induced memory deficit in the rat. Cognitive improving effect and neuronal activity of ID were assessed by using Morris water maze (MWM) test and choline acetyltransferase (ChAT), cAMP-response element-binding protein (CREB) immunohistochemistry. Seven days after TMT injection (8.0 mg/kg, i.p.), each group of rats was administered saline, water extract of ID (WID, 400 or 800 mg/kg, p.o.), ethanol extract of ID (EID, 400 or 800 mg/kg, p.o.), or caffeic acid (CAF, 30 mg/kg, i.p.) daily for fourteen days. Results: Treatment with EID and CAF produced a significant improvement in escape latency time of the acquisition, and retention time in the target area of the MWM task. Additionally, administration of EID or CAF markedly alleviated TMT-induced loss of ChAT- and CREB-immunoreactive cells in the hippocampus. The results demonstrated that EID has a protective effect against TMT-induced memory deficit, partly through increasing the CREB and cholinergic signaling pathway in the hippocampus. These results suggest that ethanol extracts of ID might be useful for improving cognitive functions in neurodegenerative diseases such as Alzheimer’s disease. Full article

Secondary metabolites are bioactive compounds believed to contribute to the pharmacological properties of plants. MicroRNAs (miRNAs) are small non-coding RNA molecules involved in post-transcriptional regulation and are thought to play an important role in regulating secondary metabolism biosynthesis. Nevertheless, the extent of miRNA involvement in secondary metabolism remains minimal. Nigella sativa (black cumin/black seed) is a popular medicinal and culinary plant known for its pharmaceutical properties; however, its genomic information is scarce. In this study, next-generation sequencing (NGS) technology was employed to obtain the miRNA profile of N. sativa, and their involvement in secondary metabolite biosynthesis was explored. A total of 25,139,003 unique reads ranging from 16 to 40 nucleotides were attained, out of which 240 conserved and 34 novel miRNAs were identified. Moreover, 6083 potential target genes were recognized in this study. Several conserved and novel black cumin miRNAs were found to target enzymes involved in the terpenoid, diterpenoid, phenylpropanoid, carotenoid, flavonoid, steroid, and ubiquinone biosynthetic pathways, among others, for example, beta-carotene 3-hydroxylase, gibberellin 3 beta-dioxygenase, trimethyltridecatetraene synthase, carboxylic ester hydrolases, acetyl-CoA C-acetyltransferase, isoprene synthase, peroxidase, shikimate O-hydroxycinnamoyltransferase, etc. Furthermore, sequencing data were validated through qPCR by checking the relative expression of eleven randomly selected conserved and novel miRNAs (nsa-miR164d, nsa-miR166a, nsa-miR167b, nsa-miR171a, nsa-miR390b, nsa-miR396, nsa-miR159a, nsa-miRN1, nsa-miRN29, nsa-miRN32, and nsa-miRN34) and their expression patterns were found to be corroborated with the sequencing data. We anticipate that this work will assist in clarifying the implications of miRNAs in plant secondary metabolism and aid in the generation of artificial miRNA-based strategies to overproduce highly valuable secondary metabolites from N. sativa. Full article

Serotonin N-acetyltransferase (SNAT) is a pivotal enzyme for melatonin biosynthesis in all living organisms. It catalyzes the conversion of serotonin to N-acetylserotonin (NAS) or 5-methoxytrypytamine (5-MT) to melatonin. In contrast to animal- and plant-specific SNAT genes, a novel clade of archaeal SNAT genes has recently been reported. In this study, we identified homologues of archaeal SNAT genes in ciliates and dinoflagellates, but no animal- or plant-specific SNAT homologues. Archaeal SNAT homologue from the ciliate Stylonychia lemnae was annotated as a putative N-acetyltransferase. To determine whether the putative S. lemnae SNAT (SlSNAT) exhibits SNAT enzyme activity, we chemically synthesized and expressed the full-length SlSNAT coding sequence (CDS) in Escherichia coli, from which the recombinant SlSNAT protein was purified by Ni²⁺ affinity column chromatography. The recombinant SlSNAT exhibited SNAT enzyme activity toward serotonin (K_m = 776 µM) and 5-MT (K_m = 246 µM) as substrates. Furthermore, SlSNAT-overexpressing (SlSNAT-OE) transgenic rice plants showed higher levels of melatonin synthesis than wild-type controls. The SlSNAT-OE rice plants exhibited delayed leaf senescence and tolerance against treatment with the reactive oxygen species (ROS)-inducing herbicide butafenacil by decreasing hydrogen peroxide (H₂O₂) and malondialdehyde (MDA) levels, suggesting that melatonin alleviates ROS production in vivo. Full article

Plant cell walls are largely composed of polysaccharide polymers, including cellulose, hemicelluloses (xyloglucan, xylan, mannan, and mixed-linkage β-1,3/1,4-glucan), and pectins. Among these cell wall polysaccharides, xyloglucan, xylan, mannan, and pectins are often O-acetylated, and polysaccharide O-acetylation plays important roles in cell wall assembly and disease resistance. Genetic and biochemical analyses have implicated the involvement of three groups of proteins in plant cell wall polysaccharide O-acetylation: trichome birefringence-like (TBL)/domain of unknown function 231 (DUF231), reduced wall acetylation (RWA), and altered xyloglucan 9 (AXY9). Although the exact roles of RWAs and AXY9 are yet to be identified, members of the TBL/DUF231 family have been found to be O-acetyltransferases responsible for the O-acetylation of xyloglucan, xylan, mannan, and pectins. Here, we provide a comprehensive overview of the occurrence of O-acetylated cell wall polysaccharides, the biochemical properties, structural features, and evolution of cell wall polysaccharide O-acetyltransferases, and the potential biotechnological applications of manipulations of cell wall polysaccharide acetylation. Further in-depth studies of the biochemical mechanisms of cell wall polysaccharide O-acetylation will not only enrich our understanding of cell wall biology, but also have important implications in engineering plants with increased disease resistance and reduced recalcitrance for biofuel production. Full article

This study investigated the transcriptomic mechanisms underlying melatonin accumulation and the enhancement of salt tolerance in hull-less barley seeds subjected to zinc sulphate stress. Following zinc sulphate treatment, hull-less barley seeds demonstrated increased melatonin accumulation and improved salt tolerance. Through transcriptome analysis, the study compared gene expression alterations in seeds (using the first letter of seed, this group is marked as ‘S’), seeds treated with pure water (as the control group, is marked as ‘C’), and germinated seeds exposed to varying concentrations of zinc sulphate (0.2 mM and 0.8 mM, the first letter of zinc sulphate, ‘Z’, is used to mark groups ‘Z1’ and ‘Z2’). The analysis revealed that 8176, 759, and 622 differentially expressed genes (DEGs) were identified in the three comparison groups S.vs.C, C.vs.Z1, and C.vs.Z2, respectively. Most of the DEGs were closely associated with biological processes, including oxidative-stress response, secondary metabolite biosynthesis, and plant hormone signaling. Notably, zinc sulphate stress influenced the expression levels of Tryptophan decarboxylase 1 (TDC1), Acetylserotonin O-methyltransferase 1 (ASMT1), and Serotonin N-acetyltransferase 2 (SNAT2), which are key genes involved in melatonin synthesis. Furthermore, the expression changes of genes such as Probable WRKY transcription factor 75 (WRKY75) and Ethylene-responsive transcription factor ERF13 (EFR13) exhibited a strong correlation with fluctuations in melatonin content. These findings contribute to our understanding of the mechanisms underlying melatonin enrichment in response to zinc sulphate stress. Full article

L-cysteine, a precursor of essential components for plant growth, is synthesized by the cysteine synthase complex, which includes O-acetylserine(thiol) lyase (OAS-TL) and serine acetyltransferase. In this work, we investigated how S-benzyl-L-cysteine (SBC), an OAS-TL inhibitor, affects the growth, photosynthesis, and oxidative stress of Ipomoea grandifolia plants. SBC impaired gas exchange and chlorophyll a fluorescence, indicating damage that compromised photosynthesis and reduced plant growth. Critical parameters such as the electron transport rate (J), triose phosphate utilization (TPU), light-saturation point (LSP), maximum carboxylation rate of Rubisco (V_cmax), and light-saturated net photosynthetic rate (P_Nmax) decreased by 19%, 20%, 22%, 23%, and 24%, respectively. The photochemical quenching coefficient (q_P), quantum yield of photosystem II photochemistry (ϕ_PSII), electron transport rate through PSII (ETR), and stomatal conductance (g_s) decreased by 12%, 19%, 19%, and 34%, respectively. Additionally, SBC decreased the maximum fluorescence yield (F_m), variable fluorescence (F_v), and chlorophyll (SPAD index) by 14%, 15%, and 15%, respectively, indicating possible damage to the photosynthetic apparatus. SBC triggered root oxidative stress by increasing malondialdehyde, reactive oxygen species, and conjugated dienes by 30%, 55%, and 61%, respectively. We hypothesize that dysfunctions in sulfur-containing components of the photosynthetic electron transport chain, such as the cytochrome b₆f complex, ferredoxin, and the iron–sulfur (Fe-S) centers are the cause of these effects, which ultimately reduce the efficiency of electron transport and hinder photosynthesis in I. grandifolia plants. In short, our findings suggest that targeting OAS-TL with inhibitors like SBC could be a promising strategy for the development of novel herbicides. Full article

The compound 15-deacetylcalonectrin (15-deCAL) is a common pathway intermediate in the biosynthesis of Fusarium trichothecenes. This tricyclic intermediate is metabolized to calonectrin (CAL) by trichothecene 15-O-acetyltransferase encoded by Tri3. Unlike other trichothecene pathway Tri gene mutants, the Δtri3 mutant produces lower amounts of the knocked-out enzyme’s substrate 15-deCAL, and instead, accumulates higher quantities of earlier bicyclic intermediate and shunt metabolites. Furthermore, evolutionary studies suggest that Tri3 may play a role in shaping the chemotypes of trichothecene-producing Fusarium strains. To better understand the functional role of Tri3p in biosynthesis and evolution, we aimed to develop a method to produce 15-deCAL by using transgenic Fusarium graminearum strains derived from a trichothecene overproducer. Unfortunately, introducing mutant Tri3, encoding a catalytically impaired but structurally intact acetylase, did not improve the low 15-deCAL production level of the ΔFgtri3 deletion strain, and the bicyclic products continued to accumulate as the major metabolites of the active-site mutant. These findings are discussed in light of the enzyme responsible for 15-deCAL production in trichothecene biosynthesis machinery. To efficiently produce 15-deCAL, we tested an alternative strategy of using a CAL-overproducing transformant. By feeding a crude CAL extract to a Fusarium commune strain that was isolated in this study and capable of specifically deacetylating C-15 acetyl, 15-deCAL was efficiently recovered. The substrate produced in this manner can be used for kinetic investigations of this enzyme and its possible role in chemotype diversification. Full article

Baccatin III is a crucial precursor in the biosynthesis pathway of paclitaxel. Its main sources are extraction from Taxus or chemical synthesis using 10-deacetylbaccatin III (10-DAB) as substrate. However, these preparation approaches exhibit serious limitations, including the low content of baccatin III in Taxus and the complicated steps of chemical synthesis. Heterologous expression of 10-deacetylbaccatin III-10-O-acetyltransferase (TcDBAT) in microbial strains for biotransformation of 10-DAB is a promising alternative strategy for baccatin III production. Here, the promotion effects of glycerol supply and slightly acidic conditions with a low-temperature on the catalysis of recombinant TcDBAT strain were clarified using 10-DAB as substrate. Taxus needles is renewable and the content of 10-DAB is relatively high, it can be used as an effective source of the catalytic substrate 10-DAB. Baccatin III was synthesized by integrating the extraction of 10-DAB from renewable Taxus needles and in situ whole-cell catalysis in this study. 40 g/L needles were converted into 20.66 mg/L baccatin III by optimizing and establishing a whole-cell catalytic bioprocess. The method used in this study can shorten the production process of Taxus extraction for baccatin III synthesis and provide a reliable strategy for the efficient production of baccatin III by recombinant strains and the improvement of resource utilization rate of Taxus needles. Full article

Aberrant expression of the pluripotency-associated transcription factor Sox2 is associated with poor prognosis in colorectal cancer (CRC). We investigated the regulatory roles of major post-translational modifications in Sox2 using two CRC cell lines, SW480 and SW620, derived from the same patient but with low and high Sox2 expression, respectively. Acetylation of K75 in the Sox2 nuclear export signal was relatively increased in SW480 cells and promotes Sox2 nucleocytoplasmic shuttling and proteasomal degradation of Sox2. LC-MS-based proteomics analysis identified HDAC4 and p300 as binding partners involved in the acetylation-mediated control of Sox2 expression in the nucleus. Sox2 K75 acetylation is mediated by the acetyltransferase activity of CBP/p300 and ACSS3. In SW620 cells, HDAC4 deacetylates K75 and is regulated by miR29a. O-GlcNAcylation on S246, in addition to K75 acetylation, also regulates Sox2 stability. These findings provide insights into the regulation of Sox2 through multiple post-translational modifications and pathways in CRC. Full article

L-cysteine is a proteogenic amino acid with many applications in the pharmaceutical, food, animal feed, and cosmetic industries. Due to safety and environmental issues in extracting L-cysteine from animal hair and feathers, the fermentative production of L-cysteine offers an attractive alternative using renewable feedstocks. Strategies to improve microbial production hosts like Pantoea ananatis, Corynebacterium glutamicum, Pseudomonas sp., and Escherichia coli are summarized. Concerning the metabolic engineering strategies, the overexpression of feedback inhibition-insensitive L-serine O-acetyltransferase and weakening the degradation of L-cysteine through the removal of L-cysteine desulfhydrases are crucial adjustments. The overexpression of L-cysteine exporters is vital to overcome the toxicity caused by intracellular accumulating L-cysteine. In addition, we compiled the process engineering aspects for the bioproduction of L-cysteine. Utilizing the energy-efficient sulfur assimilation pathway via thiosulfate, fermenting cheap carbon sources, designing scalable, fed-batch processes with individual feedings of carbon and sulfur sources, and implementing efficient purification techniques are essential for the fermentative production of L-cysteine on an industrial scale. Full article