Bioscience, Biotechnology, and Biochemistry最新文献

We developed a simple and effective method for distinguishing mature spores of Bacillus subtilis 168 from mixed cell population using Auramine O (AuO) staining combined with flow cytometry (FCM) analysis. AuO preferentially stains mature spores, enabling fluorescence-based discrimination. To optimize the method, B. subtilis 168 were stained with AuO and heated at different temperatures (25, 40, 55, or 70 °C) before FCM analysis. Among the tested conditions, heating for 30 min at 55 °C yielded the most distinct separation between mature spores and other cell types based on fluorescence intensity. This approach combines the high-throughput capability of FCM with temperature-enhanced fluorescent staining to achieve efficient and accurate spore identification. This method is simple, rapid, and scalable, with potential applications in food safety testing and probiotic product manufacturing, where fast and reliable bacterial enumeration is essential.

Selenate and tellurate are toxic chalcogen oxyanions that can be reduced by several bacteria to the less-toxic elemental forms of selenium and tellurium. In Escherichia coli, the ynfEFGH gene cluster encodes two complex iron-sulfur molybdoenzymes, YnfEGH and YnfFGH, involved in this reduction. This study investigated the functional relationship between the two catalytic subunits, YnfE and YnfF. Phylogenetic analysis revealed that their homologs were divided into three major clades, with YnfE and YnfF belonging to different subclades within the same clade. Reductase assays using gene-disruption strains revealed that selenate was mainly reduced by YnfE, whereas tellurate was reduced by both YnfE and YnfF. Analysis of the reaction product indicated that YnfE and YnfF catalyzed the two-electron reduction of selenate/tellurate to selenite/tellurite. These findings suggest that selenate and tellurate are initially reduced to selenite and tellurite, which are subsequently converted to elemental selenium and tellurium by intracellular thiols in E. coli.

We showed that several phytochemicals, but not nutrients, significantly decreased intracellular ATP levels in HT-29 human colon adenocarcinoma cells. Curcumin, one of the active compounds, markedly inhibited the proliferation of HT-29 cells, which was exaggerated in low-glucose media and lipase-downregulated cells as well. In addition, curcumin significantly induced lipolysis. Collectively, curcumin may inhibit cancer cell growth by inducing energy starvation.

The need for eco-friendly pest control has grown with increasing concerns over toxicity of synthetic pesticides. Repellents offer a nonlethal alternative for crop protection. Here, we report the identification of naturally occurring organic acids as repellents for agricultural pests. We evaluated the repellent activity of methanolic extracts of 12 Persicaria species against pillbug. All extracts showed significant activity, with that from P. chinensis being the most effective. Bioassay-guided isolation from P. chinensis shoots revealed oxalic acid as the principal active compound. Oxalic acid and related dicarboxylic acids exhibited concentration-dependent repellency, indicative of the influence of both acidity and molecular structure on the activity. Oxalic acid was detected in all species and was generally more abundant in the shoots, partially correlating with the repellent strength. This study reveals a previously unrecognized defensive role of plant organic acids and highlights their potential as safe, biodegradable agents for pest management.

Salmon milt extract (SME) is rich in deoxyribonucleic acids and has been suggested as a functional material. However, whether these components contribute to SME's functionality remains unclear, and data on their intestinal absorption are limited. This study investigated absorption mechanisms of deoxyribonucleic acid components in SME using in-situ and in vitro models. UPLC-MS/MS was used to simultaneously quantify four deoxyribonucleosides (dNs). The in-situ rat intestinal loop study showed increased levels of 2'-deoxyadenosine (dAdo) and 2'-deoxyguanosine (dGuo) in the portal vein. In the transcellular transport assay, dAdo and dGuo levels on the receiver side increased in a time-dependent manner after SME treatment, particularly in human induced pluripotent stem cell-derived small intestinal epithelial cells. No increase in 2'-deoxycytidine or thymidine levels was observed under any experimental condition. These results indicate that purine dNs are absorbed into the portal vein after oral intake of SME, whereas intestinal absorption of pyrimidine dNs is limited.

The stringent response is a conserved stress‑adaptation programme in bacteria, mediated by the alarmones (p)ppGpp that reprogramme transcription, translation and metabolism. This mini‑review surveys mechanistic, physiological and evolutionary facets of alarmone signalling across two classes of RelA/SpoT homologue (RSH) enzymes: multi domain-containing long RSHs and small alarmone synthetases/hydrolases (SAS/SAH). We first outline how activation is ribosome‑centred: in Escherichia coli, synthesis‑only RelA is activated only when bound to a starved ("hungry") ribosome, while SpoT is hydrolase‑biased; in Bacillus subtilis, a single bifunctional Rel shifts from hydrolysis- to synthesis-state when locked on a starved ribosome. Beyond (p)ppGpp, SAS enzymes diversify outputs by producing adenosine alarmones such as (p)ppApp and, in toxic SAS (toxSAS) modules, by pyrophosphorylating the tRNA 3'‑CCA end. Finally, we discuss evolutionary trajectories-from SAH-SAS operons to fused, ribosome‑regulated long RSHs-and argue that pseudo‑ZFD motifs in some toxSAS likely represent independent acquisitions.

Hyperglycemia activates the polyol pathway, producing fructose, which promotes glycation and denatures α-crystallin, ultimately leading to diabetic cataracts. This study compared the antiglycation effects of SMR and SBN, using a fructose-induced human αA-crystallin glycation model. Through fluorescence analysis, SDS-PAGE, and Western blotting methods, we found that glycation caused αA-crystallin to form fluorescent advanced glycation end products (AGEs), cross-linking AGEs, and Nε-carboxymethyllysine (CML). Results show that SMR (> 20 μg/mL) and SBN (> 100 μg/mL) effectively inhibited cross-linking AGEs and CML formation. At concentrations above 4 μg/mL, both significantly reduced fluorescent AGEs, with SMR showing 91.0 ± 0.8% inhibition and SBN 81.1 ± 1.7% at 100 μg/mL. SMR also outperformed aminoguanidine hydrochloride in reducing carbonyl content at 500 μg/mL. Therefore, SMR exhibited stronger antiglycation and anti-oxidation properties than SBN, showing potential as a natural health product to prevent diabetic cataract formation.

Transplanting allogeneic or even interspecies mitochondria to modulate cancer malignancy was investigated herein. Melanoma is a highly metastatic cancer that strongly relies on mitochondrial function. The mitochondrial membrane potential (MMP) and ATP of human (A375) and mouse (B16F10) melanoma cells, and four donor cells, human (HaCaT) and mouse (MPEK-BL6) keratinocytes, human (HUVEC) and mouse (MUVEC) endothelial cells were compared. The mitochondrial transplantations between mouse and human were identified. HUVEC mitochondria could uniquely retard the migration of B16F10. HUVEC mitochondria could be substantially transplanted into B16F10 and were colocalized with endogenous B16F10 mitochondria, in which, the branched mitochondria were converted into globular mitochondria. The reduced DRP1 and LC3 II corresponded to the reduced MMP and ATP. The decreased TGF-β, NANOG, SOX2, SMAD2/3, AKT, ERK, N-cadherin and MMP-9 corresponded to the attenuated invasion, elevated ROS and impaired cell viability. In conclusion, the feasibility of interspecies mitochondrial transplantation was preliminarily validated.

Brown algae are promising sources of blue carbon for biofuel production. The non-motile Sphingomonas sp. strain A1 imports alginate, a major component of brown algae, by alginate-binding proteins AlgQ1/Q2 and ATP-binding cassette transporter. Previously, we showed that metabolically engineered ethanol-fermentative strains A1 (A1-EPv14 and A1-EPv104) produced bioethanol from alginate, and that repeated subculturing of strain A1 on soft agar plates inducibly activated motility, resulting in expression of chemotaxis toward alginate. This study examined the possibility of bioethanol production directly from brown algae, and what triggers chemotaxis and how chemotaxis affects ethanol yield. Strain A1-EPv104 produced ethanol from brown algae as well as alginate. Gene disruption and complementation revealed that AlgQ2, not AlgQ1, was involved in alginate chemotaxis. Compared with non-motile strain A1-EPv14, strain A1-EPv14c exhibiting alginate chemotaxis produced ethanol from alginate more rapidly. This is the first report on chemotaxis-associated biotechnology for rapid production of bioethanol from blue carbon alginate.

Epithelial-mesenchymal transition (EMT) is an essential event during the initial steps of the cancer metastasis process. Resveratrol, a natural polyphenolic compound, has received considerable attention for its inhibitory effects on cancer metastasis through the prevention of EMT, but the specific mechanisms have not yet been fully elucidated. To address this issue, we investigated the effects of resveratrol on the migration of SW480 cells using a high glucose-induced EMT model. The data revealed that resveratrol inhibited the high glucose-induced migration of SW480. Resveratrol also decreased the levels of heat shock factor 1 (HSF1), a modulator of EMT marker molecules, which is often overexpressed in cancer cells. Resveratrol-induced HSF1 suppression was linked to the inhibition of EMT-associated cell migration. Furthermore, resveratrol reduced HSF1 expression by inducing a proteasome-mediated degradation. Our results provide the first evidence that resveratrol inhibits the EMT of cancer cells, which might be involved in the suppression of HSF1.