Sulfoquinovose (SQ) serves as the polar head group of sulfolipids in photosynthetic organisms. Given the substantial biomass of these organisms, the estimated global annual production of SQ is around 10 billion tons, making it one of the most abundant sulfur-containing organic compounds in nature. The microbial degradation of SQ constitutes a critical component of the global sulfur cycle and is increasingly recognized for its relevance to human health, particularly through its metabolism by the gut bacteria. Microorganisms employ two principal classes of catabolic pathways to degrade SQ: (i) C-S bond cleavage pathways, including the sulfo-ASMO (alkanesulfonate monooxygenase-dependent) and sulfo-ASDO (alkanesulfonate dioxygenase-dependent) pathways, which release glucose and sulfite; and (ii) C-C bond cleavage pathways, including sulfo-EMP (sulfoglycolytic Embden-Meyerhof-Parnas), sulfo-ED (sulfoglycolytic Entner-Doudoroff), sulfo-TAL (sulfoglycolytic transaldolase), and sulfo-TK (sulfoglycolytic transketolase) pathways, which yield short-chain sulfonates such as sulfolactate (SL) and dihydroxypropanesulfonate (DHPS). These sulfonated intermediates can undergo further degradation, releasing sulfite and short chain carbohydrates. Sulfite-reducing Bilophila wadsworthia utilizes them to generate respiratory terminal electron acceptor forming H₂S, which is toxic and a potential cause of inflammation and colon cancer. Here we systematically review the SQ catabolic pathways and the degradation mechanisms of the sulfonated intermediates. In addition, the significant implications of SQ degradation in human gut are discussed briefly.

The phenolic metabolite p-cresol is a byproduct of tyrosine fermentation by certain strictly anaerobic bacteria, including the human gut pathogen Clostridium difficile, with toxic effects on the host and intestinal microbiota. The only enzyme in this biochemical pathway characterized to date is the glycyl radical enzyme p-hydroxyphenylacetate (HPA) decarboxylase (HPAD), which catalyzes the terminal step. Here we report the identification and characterization of enzymes for anaerobic degradation of tyrosine to HPA in the model p-cresol-producing bacterium Clostridium scatologenes. In this pathway, tyrosine is first converted to p-hydroxyphenylpyruvate (HPP), followed by net oxidation to HPA by a trio of enzymes HPP: ferredoxin oxidoreductase (HpdDEFG), phosphate HPA-transferase (HpdJ) and HPA kinase (HpdK). Each step is thermodynamically reversible, and the pathway is coupled to net generation of ATP and reduced ferredoxin. A bioinformatics search reveals that gene clusters containing a similar trio of enzymes are widespread in anaerobic Firmicutes bacteria, suggesting analogous pathways for the degradation of other amino acids. These findings clarify the oxidative pathways by which anaerobic gut bacteria convert aromatic amino acids into a major class of aromatic metabolites including HPA and p-cresol, deepening our understanding of microbiota-host metabolic interactions.

IntroductionIn recent years, with the continuous expansion of aquaculture areas worldwide and the outbreak of diseases, the use of antibiotics and chemical drugs is limited. Plant polysaccharides have received widespread attention due to their multiple bioactivities. However, research on the combined use of plant polysaccharides and Bacillus coagulans is still insufficient. Therefore, this study focuses on the impact of B.coagulans-fermented polysaccharides on Macrobrachium nipponense.MethodsAn 8-week feeding trial was conducted with seven groups: the control group (CT) and the Bacillus coagulans group (N),Atractylodes macrocephala polysaccharides group (NB), Saposhnikovia divaricata polysaccharides group (NF), Mannose group (NG), Astragalus polysaccharides group (NH) and Yu ping feng polysaccharides group (NP).Results and discussionThe research results indicate that compared to the CT, the levels of AST and ALT were reduced in the group of N, NF and NG. The NF showed a significant increase in total antioxidant capacity (T-AOC) and total superoxide dismutase (SASC) levels. The NP had a significant increase in T-AOC and superoxide anion scavenging ability. The levels of total protein (TP) and malondialdehyde (MDA) in the group of NG, NB, and NP were significantly higher than those in the CT and N. Compared to the CT, the expression of Toll in the NP group, Myd88 and Dorsal in the NH group, and IMD and Relish in the NF and NP group were all significantly increased. Conversely, the expression of IMD in the NB and NG group and Relish in the NG group was significantly decreased. Additionally, the survival rate in the NP group was significantly higher than in other groups, and the NB group enhanced the weight gain of M.nipponense compared to the N. In summary, B.coagulans fermented with Yupingfeng polysaccharides and Astragalus polysaccharides can significantly enhance the antioxidant and immune capabilities of M.nipponense.

Angiotensin-I-converting enzyme inhibitory peptides were isolated from Cassia obtusifolia seeds by alcalase hydrolysis. Using ultrafiltration, the peptides were divided into four fractions (<1, 1–3, 3–5, >5 kDa). The fraction below 1 kDa exhibited the appropriate ACE inhibition (IC50 = 65.88 μg/mL), and was further purified by gel filtration chromatography, which displayed better angiotensin-I-converting enzyme inhibitory activity (IC50 = 53.67 μg/mL). The amino acid sequences of three novel angiotensin-I-converting enzyme inhibitory peptides were identified by liquid chromatography with tandem mass spectrometry as follows: IFPGCAN (IC50 = 23.71 μM), TEDFLTQ (IC50 = 32.82 μM), and GDEGSGGIIR (IC50 = 18.21 μM). Further experiments demonstrated that IFPGCAN and TEDFLTQ were competitive inhibitors, while GDEGSGGIIR was a noncompetitive inhibitor of the angiotensin-I-converting enzyme. Three peptides could form hydrogen bonds with the active site of the angiotensin-I-converting enzyme, according to molecular docking simulations of their interaction with the angiotensin-I-converting enzyme.

Intensification of poultry industry has led to a surge in animal product output, but this has also revealed issues with environmental management in poultry houses, particularly the harmful effects of high hydrogen sulfide (H2S) levels on poultry health. The study aimed to assess the therapeutic impact of tea tree oil (TTO) on H2S-induced spleen and intestinal injuries in chickens. A total of 240 one-day-old Lohmann Brown chicks were randomly divided into three groups: the control group (CON), the H2S exposure group (AVG), and the TTO treatment group (TTG), with four replicates, each consisting of 20 chicks. The experiment lasted 42 days. Results showed that TTO treatment alleviated tissue damage in the thymus, kidneys, spleen, and bursa of Fabricius, and improved the organ index (P < 0.05) compared with the AVG. Serum analysis revealed that TTO lowered levels of alanine aminotransferase(ALT), aspartate aminotransferase(AST), triglycerides(TG), CD3 positive CD4 positive T cells(CD3+CD4+), CD4 positive to CD8 positive Rratio(CD4+/CD8+), and alkaline phosphatase(AKP), while increasing albumin(ALB), globulin(GLO), immunoglobulin A(IgA), and immunoglobulin G(IgG) levels (P < 0.05). Intestinal findings indicated that TTO treatment enhanced villus height, reduced crypt depth, and upregulated the expression of Claudin 1, Occludin, and ZO-1 mRNA in the jejunum (P < 0.05). After TTO treatment, H2S-induced oxidative stress injury and apoptosis protein expression in spleen were improved (P < 0.05). TTO also reduced interferon-γ(INF-γ), tumor necrosis factor-α(TNF-α) and interleukin-1β(IL-1β) proteins (P < 0.05), while raising CD3+CD8+ T-cell subsets (P < 0.05).Compared with CON, TTO treatment alleviated serum biochemical disorders and intestinal damage caused by H2S exposure and restored them to normal (P > 0.05). In conclusion, TTO can improve spleen and intestinal function and reduce the effects of H2S on growth performance and health of chickens.

Bombyx mori is an oligophagous economic insect. Cis-Jasmone is one of the main substances in mulberry leaf that attract silkworm for feeding and BmOR56 is its receptor. Potential interaction ways between BmOR56 and cis-Jasmone were explored, which included some crucial amino acids such as Gln172, Val173, Ser176, Lys182, His322, and Arg345. BmOR56 was edited using CRISPR/cas9 for Qiufeng, and a homozygous knockout strain QiufengM was obtained. Compared with Qiufeng, the feeding ability of QiufengM on mulberry leaf did not change significantly, but on artificial diet decreased significantly. QiufengM also showed a dependence on the concentration of mulberry leaf powder. The result indicated that other olfactory genes had a compensatory effect on the attractance of mulberry leaf after the loss of BmOR56. Transcriptome analysis of antennae showed that many genes differentially expressed between Qiufeng and QiufengM, which involved in olfactory system, glucose metabolism, protein metabolism, amino acid metabolism, and insect hormone biosynthesis. Particularly, BmIR21, BmOR53 and BmOR27 were significantly up-regulated, which may have a compensatory effect on BmOR56 loss. In addition, detoxification mechanism was activated and may cause the passivation of feeling external signals in silkworm.

Sulfoquinovose (SQ), the polar head group of sulfolipids essential for photosynthesis, is naturally abundant. Anaerobic Firmicutes degrade SQ through a transaldolase-dependent (sulfo-TAL) pathway, producing dihydroxypropanesulfonate (DHPS). Some bacteria extend this pathway by the sequential action of HpfG and HpfD converting DHPS to 3-hydroxypropanesulfonate (3-HPS) via 3-sulfopropionaldehyde (3- SPA). Here, we report a variant sulfo-TAL pathway in Enterococcus gilvus, involving additional enzymes, a NAD+-dependent +-dependent 3-SPA dehydrogenase HpfX, and a 3-sulfopropionyl-CoA synthetase HpfYZ, which oxidize 3-SPA to 3-sulfopropionate (3-SP) coupled with ATP formation. E. gilvus grown on SQ or DHPS produced a mixture of 3-HPS and 3-SP, indicating the bifurcated pathway. Similar genes are found in various Firmicutes, including gut bacteria. Importantly, 3-SP, but not 3-HPS, can serve as a respiratory terminal electron acceptor for Bilophila wadsworthia, a common intestinal pathobiont, resulting in the production of toxic H2S. 2 S. This research expands our understanding of sulfonate metabolism and reveals cross-feeding in the anaerobic microbiome.

Three new compounds, including two glycosides, named gerbelavinsides E/G (1/2), and a flavone, named gerbelavin G (3), were isolated from 50% ethanol extract of Gerbera delavayi. Their structures were elucidated based on HR-ESI-MS, IR, UV and NMR spectral data, and the absolute configurations of 1 and 3 were determined by ECD spectra. Three compounds were tested for their inhibition effect against LPS-induced NO production in RAW 264.7 cells. They exhibited different degrees of inhibition activities with rates of 40.55 ± 1.65%, 70.13 ± 0.55%, 56.74 ± 1.15%, respectively.

Glycyl radical enzymes (GREs) catalyze mechanistically diverse radical-mediated reactions, playing important roles in the metabolism of anaerobic bacteria. The model bacterium Escherichia coli MG1655 contains two GREs of unknown function, YbiW and PflD, which are widespread among human intestinal bacteria. Here, we report that YbiW and PflD catalyze ring-opening C-O cleavage of 1,5-anhydroglucitol-6-phosphate (AG6P) and 1,5-anhydromannitol-6-phosphate (AM6P), respectively. The product of both enzymes, 1-deoxy-fructose-6-phosphate (DF6P), is then cleaved by the aldolases FsaA or FsaB to form glyceraldehyde-3-phosphate (G3P) and hydroxyacetone (HA), which are then reduced by the NADH-dependent dehydrogenase GldA to form 1,2-propanediol (1,2-PDO). Crystal structures of YbiW and PflD in complex with their substrates provided insights into the mechanism of radical-mediated C-O cleavage. This "anhydroglycolysis" pathway enables anaerobic growth of E. coli on 1,5-anhydroglucitol (AG) and 1,5-anhydromannitol (AM), and we probe the feasibility of harnessing this pathway for the production of 1,2-PDO, a highly demanded chiral chemical feedstock, from inexpensive starch. Discovery of the anhydroglycolysis pathway expands the known catalytic repertoire of GREs, clarifies the hitherto unknown physiological functions of the well-studied enzymes FsaA, FsaB, and GldA, and demonstrates how enzyme discovery efforts can cast light on prevalent yet overlooked metabolites in the microbiome.

More than 600 mutations have been discovered in the history of silkworm domestication. It is important to study the formation mechanism of these mutations to further understand the life and development process of silkworms and agricultural pest control. The silkworm mutant smb was isolated from silkworm strain NCV, and transcriptome analysis was performed on the silkworm mutant. 796 differentially expressed genes (DEGs) were detected at 48 h of the second instar stage with 669 genes significantly upregulated and 127 genes significantly downregulated. During the GO enrichment analysis, it was found that the enrichment of biological processes was mainly concentrated in proteolysis, carbohydrate metabolism, aminoglycan metabolism, organic substance metabolism, protein metabolism and so on. Based on the analysis of KEGG pathways, it revealed that the pathways enriched in lysosomes, AMPK signaling, fatty acid metabolism, PPAR signaling, galactose metabolism, and protein digestion and absorption were the most significant. Through these most significantly enriched GO terms and KEGG pathways, DEGs consistent with the phenotypic characteristics of the smb mutant were identified, including small body size, slow development, and successive death after the fourth instar. These results provided experimental evidence for the potential formation mechanism of smb mutants.

Iron (Fe) is an indispensable trace mineral element for the normal growth of plants, and it is involved in different biological processes; Fe shortage in plants can induce chlorosis and yield loss. The objective of this research is to identify novel genes that participated in the regulation of Fe-deficiency stress in Arabidopsis thaliana. A basic helix-loop-helix (bHLH) transcription factor (MYC1) was identified to be interacting with the FER-LIKE IRON DEFICIENCY-INDUCED TRANSCRIPTION FACTOR (FIT) using a yeast-two-hybrid assay. Transcript-level analysis showed that there was a decrease in MYC1 expression in Arabidopsis to cope with Fe-deficiency stress. Functional deficiency of MYC1 in Arabidopsis leads to an increase in Fe-deficiency tolerance and Fe-accumulation, whereas MYC1-overexpressing plants have an enhanced sensitivity to Fe-deficiency stress. Additionally, MYC1 inhibited the formation of FIT and bHLH38/39 heterodimers, which suppressed the expressed level for Fe acquisition genes FRO2 and IRT1 during Fe-deficiency stress. These results showed that MYC1 functions as a negative modulator of the Fe-deficiency stress response by inhibiting the formation of FIT and bHLH38/39 heterodimers, thereby suppressing the binding of FIT and bHLH38/39 heterodimers to the promoters of FRO2 and IRT1 to modulate Fe intake during Fe-deficiency stress. Overall, the findings of this study elucidated the role of MYC1 in coping with Fe-deficiency stress, and provided potential targets for the developing of crop varieties resistant to Fe-deficiency stress.

Ethylene response factors (ERFs) are involved in the regulation of plant development processes and stress responses. In this study, we provide evidence for the role of ERF022, a member of the ERF transcription factor group III, in regulating Arabidopsis root growth. We found that ERF022 -loss-of-function mutants exhibited increased primary root length and lateral root numbers, and also morphological growth advantages compared to wild-type. Further studies showed that mutants had enhanced cell size in length in the root elongation zones. These results were accompanied by significant increase in the expression of cell elongation and cell wall expansion related genes SAUR10 , GASA14 , LRX2 , XTH19 in mutants. Moreover, ERF022- mediated root growth was associated with the enhanced endogenous auxin and gibberellins levels. Our results suggest that loss-of-function of ERF022 up-regulated the expression of cell elongation and cell wall related genes through auxin and gibberellins signal in the regulation of root growth. Unexpectedly, ERF022 overexpression lines also showed longer primary roots and more lateral roots compared to wild-type, and had longer root apical meristematic zone with increased cell numbers. Overexpression of ERF022 significantly up-regulated cell proliferation, organ growth and auxin biosynthesis genes EXO , HB2 , GALK2 , LBD26 , YUC5 , which contribute to enhanced root growth. Altogether, our results provide genetic evidence that ERF022 plays an important role in regulating root growth in Arabidopsis thaliana .

The silkworm, Bombyx mori, is an important oligophagous economic insect and feeding habits of different silkworm varieties to artificial diet are different. Research on the mechanisms of feeding habits on artificial diet, and breeding of silkworm varieties adapted on artificial diet, which is a necessary condition for industrial silkworm rearing, is currently lacking. For an artificial diet, Xin was anorexic, whereas Haoyue A showed a strong appetite. When the two varieties were crossed, the F-1 generation showed a poor appetite for the artificial diet and had a setae dispersion rate of <50 %. However, the F-2 generation, self-bred progeny of F-1, had a good appetite for the artificial diet, with a setae dispersion rate of 70 %. Herein, transcriptome analysis was conducted on the F-2 generation, comparing individuals with anorexic and preferred feeding habits, and 2188 differential genes were identified, with 1524 genes up-regulated and 934 genes down-regulated. Several genes were identified to contribute to feeding habits, such as genes involved olfactory system, energy supply, and cell proliferation and differentiation. GO enrichment revealed a large number of DEGs related to behavior, growth, signaling, developmental process, response to stimulation, and other pathways. Furthermore, proteins closely related to feeding were expressed differently. Some DEGs were selected for qRT-PCR, and results indicated the reliability of the DEG results. The DEGs between individuals with anorexic and preferred feeding habits were screened by RNA-Seq technology, which provides a reliable reference to study molecule mechanisms of feeding habits on artificial diet.

Hydroxyprolines are highly abundant in nature as they are components of many structural proteins and osmolytes. Anaerobic degradation of trans-4-hydroxy-l-proline (t4L-HP) was previously found to involve the glycyl radical enzyme (GRE) t4L-HP dehydratase (HypD). Here, we report a pathway for anaerobic hydroxyproline degradation that involves a new GRE, trans-4-hydroxy-d-proline (t4D-HP) C-N-lyase (HplG). In this pathway, cis-4-hydroxy-l-proline (c4L-HP) is first isomerized to t4D-HP, followed by radical-mediated ring opening by HplG to give 2-amino-4-ketopentanoate (AKP), the first example of a ring opening reaction catalyzed by a GRE 1,2-eliminase. Subsequent cleavage by AKP thiolase (OrtAB) yields acetyl-CoA and d-alanine. We report a crystal structure of HplG in complex with t4D-HP at a resolution of 2.7 Å, providing insights into its catalytic mechanism. Different from HypD commonly identified in proline-reducing Clostridia, HplG is present in other types of fermenting bacteria, including propionate-producing bacteria, underscoring the diversity of enzymatic radical chemistry in the anaerobic microbiome.

Resveratrol, the most widely studied phytoalexin, derived from the skin of grapes and other fruits. Evidence from numerous studies have confirmed its extensive bioactivities, such as antioxidation, anti-inflammatory and anticancer, as well as to promote antiaging effects in organisms. However, the effect of resveratrol on prolonging the postharvest storage of tomato fruits is still unknown. Here, our data provide evidence that tomato fruits applied 200 μM resveratrol displayed a significant delay in changes of weight loss, titratable acidity, soluble solids concentration, soluble protein, vitamin C and lycopene content compared to control fruits during storage. In addition, resveratrol treatment could stimulate the antioxidant defense system to inhibit the production of ROS and down-regulate the expression of ethylene biosynthesis genes. Taken together, our results suggest that resveratrol could benefit in delaying senescence and preserving the postharvest quality of tomato fruits.

Iron is an essential micronutrient for plant growth and development. Here we provide evidence for a role of ERF96 in iron-deficiency response in Arabidopsis thaliana. The ERF96-loss-of-function mutants were found to be more tolerant to iron-deficiency stress than wild type (WT) and to have higher iron and chlorophyll content. Further studies showed that the transcriptional levels of iron-uptake related genes IRT1, FRO2, AHA2, FIT and bHLH38 in mutants were significantly higher than in WT under iron deficiency. Comparative transcriptome analysis suggested that the differentially expressed genes (DEGs) between ERF96-loss-of-function mutant and WT under iron deficiency were mainly enriched in iron uptake and chlorophyll degradation. According to the specific analysis of these two kinds of DEGs, the expression of iron uptake and transport related genes in ERF96-loss-of-function mutant was higher and the expression of chlorophyll degradation related genes was lower under iron deficiency. Furthermore, loss-of-function of ERF96 influenced the plant hormone, especially auxin and ethylene signal transduction. Altogether, our results demonstrate that loss-of-function of ERF96 increased Fe uptake and chlorophyll level through ethylene and auxin signal pathway in the regulation of iron-deficiency response in Arabidopsis.

Background Iron (Fe) is an essential mineral element that involves in many biological processes important for most plants growth and development. Fe-deficiency induces a complex series of responses in plants, involving physiological and developmental changes, to increase Fe uptake from soil. However, the molecular mechanism involved in plant Fe-deficiency is not well understood. Results Here, we found that the MNB1 (mannose-binding-lectin 1) gene is involved in the regulation of Fe-deficiency stress response in Arabidopsis thaliana . The expression abundance of MNB1 was inhibited by Fe-deficiency stress. Knockout of MNB1 led to enhanced Fe accumulation and tolerance, whereas the MNB1 -overexpressing plants were sensitive to Fe-deficiency stress. Under conditions of normal and Fe-deficiency, lower H 2 O 2 concentrations were detected in mnb1 mutant plants compared to wild type. On the contrary, higher H 2 O 2 concentrations were found in MNB1 -overexpressing plants, which was negatively correlated with malondialdehyde (MDA) levels. Furthermore, in mnb1 mutants, the transcription level of the Fe uptake- and translocation-related genes, FIT , IRT1 , FRO2 , ZIF , FRD3 , NAS4 , PYE and MYB72 , were considerably elevated during Fe-deficiency stress, resulting in enhanced Fe uptake and translocation, thereby increasing Fe accumulation. Conclusions Together, our findings show that the MNB1 gene negatively controls the Fe-deficiency response in Arabidopsis via modulating reactive oxygen species (ROS) levels and the ROS-mediated signaling pathway, thereby affecting the expression of Fe uptake- and translocation-related genes.

Cervical cancer has always been the top malignant cancer among female cancers in the world. Due to its recurrence, metastasis rate, and drug resistance, the treatment results of cervical cancer have been unsatisfactory. Apigetrin is present in a variety of fruits and vegetables and has been reported to have antioxidant, free radical scavenging, anti-inflammatory, and anticancer activities. Therefore, this study focuses on the effect of apigetrin on the autophagy of cervical cancer HeLa cells based on the previous research. The results showed that apigetrin can enhance the autophagy fluorescence of light chain 3B (LC3B), and further combined with quantitative real-time PCR (qPCR) and Western blotting found that the expression of autophagy-related genes and proteins p-mTOR, Beclin1, and LC3B increased, while the expression of AMPK, ULK1, and p62 decreased. In addition, apigetrin also promoted the release of Ca2+, the PERK/eIF2α/ATF4/chop, and IRE1α pathways activate endoplasmic reticulum (ER) stress. The addition of 4PBA proved that ER stress promoted autophagy in HeLa cells. Finally, the addition of the 3-MA indicates the relationship between autophagy and apoptosis in HeLa cells. Our results indicate that apigetrin has a certain anticancer potential and can be used as a drug adjuvant and food additive for the prevention and treatment of cervical cancer.

生物化学是高校食品类专业重要的专业基础课程.本文从课程讲授、教学互动、开放式作业和教学评价等方面探讨了我校一流本科专业建设中食品类专业生物化学课程教学改革与实践.

In recent years, Maillard peptides have attracted considerable attention of food researchers due to their distinct flavor properties in food processing. We investigated the structure and flavor properties of the newly developed low-sodium seasoning salt with sesame seed hydrolysate Maillard products (SSH-MRPs), cysteine Maillard products (Cys-MRPs), methionine Maillard products (Met-MRPs), and thiamine Maillard products (Thi-MRPs). Compared to the control group, the Cys-MRPs salt (CMS) had the smallest angle of repose, the highest bulk density, and the highest sensory score. The seasoning salt with SSH-MRPs (SMS) had appreciable hygroscopicity and thermal stability. The seasoning salt with Thi-MRPs (TMS) had the highest solubility. These MRPs seasoning salts showed better flavor characteristics and physicochemical properties, suggesting that MRPs can replace part of NaCl to develop new low sodium seasoning salts and promote their application in food flavoring systems.