Bioscience, Biotechnology, and Biochemistry最新文献

Brown algae are promising sources of blue carbon for biofuel production. The nonmotile Sphingomonas sp. strain A1 imports alginate, a major component of brown algae, by alginate-binding proteins AlgQ1/Q2 and an 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 nonmotile 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 the rapid production of bioethanol from blue carbon alginate.

Poly-γ-glutamic acid (γ-PGA) occurs in three stereochemical forms-L-, DL-, and D-polymers-and the D/L ratio profoundly affects crystallinity, degradability, and materials performance. Bacillus subtilis and related secretors typically produce DL-PGA, whereas halophilic archaea yield stereoregular L-PGA and Bacillus anthracis forms a covalently anchored D-PGA capsule. Recent work has clarified how the PgsBCA/CapBCA modules access these outputs: PgsB and PgsC build and export a purely L-Glu polymer, while the MslH-like enzyme PgsA/CapA introduces D-Glu, establishing the D/L ratio. In the extracellular space, the D/L composition of γ-PGA is shaped by stereoselective hydrolases-PgdS, NlpC/P60 DL-endopeptidases, phage-derived Pgh enzymes, and GGT-family proteins. We integrate these biosynthetic and degradative pathways into a stereochemical framework and outline how tuning epimerase activity and controlling these hydrolases may enable high-molecular-weight, L-rich γ-PGA in Bacillus for coatings, absorbents, biomedical applications, and personal-care formulations where L-PGA surpasses DL-PGA in moisture retention and stability.

Bacterial membrane vesicles (MVs) are nanosized lipid bilayer particles (20-400 nm) that package proteins, lipids, nucleic acids, and metabolites derived from parent cells. MVs are now recognized as actively produced structures that play crucial roles in bacterial physiology and host-microbe interactions. Both Gram-negative and Gram-positive bacteria, including commensals and pathogens in the gut, release MVs that mediate communication, gene transfer, and immunomodulation. This mini review summarizes recent advances in understanding MV biogenesis and function, with an emphasis on gut bacterial MVs. We outline 2 biogenetic pathways, lysis-associated and non-lytic routes, and discuss regulatory mechanisms, including environmental cues that modulate MV release. Furthermore, we highlight emerging evidence that gut bacterial MVs influence host immunity, barrier function, and disease pathogenesis, while also serving as promising vaccine platforms and diagnostic biomarkers.

Monoclonal antibodies are essential tools in biological research, diagnostics, and therapeutics. While mammalian expression systems are widely used, microbial hosts such as Escherichia coli offer cost-effective and scalable production of antibody fragments but often yield inclusion bodies requiring refolding. In this study, we report a combined strategy using a translation-enhancing SKIK peptide tag and a leucine zipper-fused Fab format to improve expression in Escherichia coli, together with a continuous, dialysis-based automated refolding system. Compared with the conventional stepwise method, the automated process recovered model antibodies with equivalent antigen-binding activity and refolding yield (approximately 98%), while reducing processing time to 40%, waste volume to 69%, and chemical consumption to 47% of the modified stepwise process. The apparatus is simple to set up and operate, making it applicable from laboratory to industrial scales. This resource-efficient and scalable approach provides a practical alternative for scalable antibody fragment production in microbial systems.

We previously demonstrated that glucosamine (GlcN) exerts anti-inflammatory effects through the inhibition of nuclear factor-κB (NF-κB) signaling, possibly via O-linked-N-acetylglucosamine (O-GlcNAc) modification. In this study, we examined the effects of GlcN and alloxan (an inhibitor of O-linked-N-acetylglucosamine transferase) on NF-κB signaling molecules in interleukin (IL)-1β-stimulated human synovial MH7A cells. GlcN-induced O-GlcNAc modification of NF-κB and markedly inhibited IL-1β-induced nuclear translocation of the NF-κB, and phosphorylation of p65 subunit. GlcN also suppressed IL-1β-induced phosphorylation and degradation of inhibitor of κB (IκB). Moreover, GlcN promoted O-GlcNAc modification of IκB kinase (IKK) β, which phosphorylates IκBα, and concurrently inhibited its phosphorylation (activation). Notably, the effects of GlcN on NF-κB, IκBα, and IKKβ were reversed by alloxan. Finally, the inhibitory effect of GlcN on IL-8 production was eliminated in IKKβ-knockdown cells. Collectively, these findings indicate that O-GlcNAc modification of IKKβ is a key mediator of GlcN-induced suppression of NF-κB signaling and inflammatory cytokine production.

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.

The stringent response is a conserved stress-adaptation program in bacteria, mediated by the alarmones (p)ppGpp that reprogram transcription, translation, and metabolism. This mini-review surveys mechanistic, physiological, and evolutionary facets of alarmone singnaling across two classes of RelA/SpoT homologue (RSH) enzymes: multidomain-containing long RSHs and small alarmone synthetases/hydrolases (SAS/SAH). We first outline how activation is ribosome-centered: 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.

Vitamin B12 is primarily present in animal-derived foods and is scarce in plant-derived foods; therefore, vegetarians and vegans are at risk of deficiency. Although furu, a traditional Chinese fermented tofu product, has been reported to contain vitamin B12, it remains unclear whether the vitamin B12 compounds present are bioactive or inactive. In this study, the vitamin B12 content of eight commercial furu products was quantified using high-performance liquid chromatography. Gray furu showed the highest level (~1.1 μg/100 g), whereas the others contained < 0.4 μg/100 g. Liquid chromatography-tandem mass spectrometry revealed that only ~9% of the total vitamin B12 in gray furu was bioactive, with most identified as inactive corrinoids. Other products showed similar profiles. These findings indicate that commercial furu products are not reliable sources of vitamin B12, although gray furu may supply a modest amount of bioactive vitamin B12.

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.

We herein report the collective synthesis of all known kauralexins (A1-A4 and B1-B4) and their putative biosynthetic intermediates isolated from Zea mays via a practical and scalable route. Our synthetic approach enabled stereoselective construction of key intermediates, clarified the stereochemical relationship between kauralexin A4 and annoglabasin E, and provided the first complete NMR spectroscopic data for kauralexins. Furthermore, we developed an efficient method for the selective synthesis of ent-isokaurene derivatives, facilitating the preparation of various oxidation products implicated in kauralexin biosynthesis. Our synthetic ent-kaurane library serves as valuable tools for biochemical investigations aimed at elucidating enzymatic functions involved in diterpenoid metabolism.