共检索到62条,权限内显示50条;
[学术文献 ] Combinatorial optimization of gene expression through recombinase-mediated promoter and terminator shuffling in yeast 进入全文
Nature Communications
Microbes are increasingly employed as cell factories to produce biomolecules. This often involves the expression of complex heterologous biosynthesis pathways in host strains. Achieving maximal product yields and avoiding build-up of (toxic) intermediates requires balanced expression of every pathway gene. However, despite progress in metabolic modeling, the optimization of gene expression still heavily relies on trial-and-error. Here, we report an approach for in vivo, multiplexed Gene Expression Modification by LoxPsym-Cre Recombination (GEMbLeR). GEMbLeR exploits orthogonal LoxPsym sites to independently shuffle promoter and terminator modules at distinct genomic loci. This approach facilitates creation of large strain libraries, in which expression of every pathway gene ranges over 120-fold and each strain harbors a unique expression profile. When applied to the biosynthetic pathway of astaxanthin, an industrially relevant antioxidant, a single round of GEMbLeR improved pathway flux and doubled production titers. Together, this shows that GEMbLeR allows rapid and efficient gene expression optimization in heterologous biosynthetic pathways, offering possibilities for enhancing the performance of microbial cell factories.
[学术文献 ] p-Anisaldehyde suppresses Aspergillus flavus infection and aflatoxin biosynthesis via targeting cell structure and Ap1-regulatory antioxidant system 进入全文
Food Frontiers
Aflatoxin, mainly produced by Aspergillus flavus, is one of the most notorious mycotoxin for its toxicity and carcinogenicity. Despite extensive efforts, effective strategies to control A. flavus and AFB1 contamination remain elusive. Here, we investigate the potential of p-anisaldehyde (AS), an aldehyde derived from plant essential oils, as a natural antifungal agent against A. flavus and its ability to modulate AFB1 biosynthesis. We found that AS exhibited broad-spectrum antifungal activities against Aspergillus spp. and effectively inhibited A. flavus asexual development, AFB1 production, and pathogenicity. AS treatment disrupted the cell surface structure and membrane integrity, as observed by scanning electron microscopy and PI staining. RNA-sequencing analysis revealed that AS significantly altered the expression of genes involved in redox homeostasis, plasma membrane function, and cell cycle progression. Further investigation demonstrated that AS induced a reduction in mitochondrial membrane potential (Δψm) and accumulation of reactive oxygen species (ROS), leading to cell cycle arrest at the G2/M phase. The AS-induced ROS accumulation was found to be mitigated by the superoxide dismutase-mediated antioxidant system, which is regulated by transcriptional factor Ap1. Notably, the Ap1-regulatory ROS detoxification system was also found to be involved in A. flavus pathogenicity and AFB1 production. Overall, these findings provide valuable insights into the inhibitory mechanism of AS against A. flavus, paving the way for its potential application as a natural strategy to mitigate AFB1 contamination in both food and agriculture crops.
[学术文献 ] Effects of host-associated low-temperature probiotics in olive flounder (Paralichthys olivaceus) aquaculture 进入全文
Scientific Reports
This study investigated the effects of supplementation of low-temperature probiotics isolated from the intestines of olive flounder on the growth performance, digestibility, and regulation of intestinal microbiota and the expression of genes related to growth, immunity, and apoptosis in olive flounder. Bacteria showing high growth at approximately 15–20 °C, which is the temperature of olive flounder culture, were isolated and confirmed to be Pseudomonas species through 16S rRNA gene sequence analysis. Whole-genome sequencing revealed that the strain has a 6,195,122 bp single circular chromosome and a guanine–cytosine content of 59.9%. In the feeding trial, supplementation with 1 × 108 CFU/g of the isolate strain positively modulated growth performances, digestive enzyme activity, and gut microbiota composition of olive flounder. RT-qPCR for the comparison of growth, immunity, and apoptosis-related gene expression levels showed no significant differences between the groups. Therefore, the isolated host-associated low-temperature probiotics improved the growth performance of olive flounder by causing positive changes in digestive activity and intestinal microbial composition without affecting host gene expression.
[学术文献 ] Designed allosteric protein logic 进入全文
Cell Discovery
The regulation of protein function by external or internal signals is one of the key features of living organisms. The ability to directly control the function of a selected protein would represent a valuable tool for regulating biological processes. Here, we present a generally applicable regulation of proteins called INSRTR, based on inserting a peptide into a loop of a target protein that retains its function. We demonstrate the versatility and robustness of coiled-coil-mediated regulation, which enables designs for either inactivation or activation of selected protein functions, and implementation of two-input logic functions with rapid response in mammalian cells. The selection of insertion positions in tested proteins was facilitated by using a predictive machine learning model. We showcase the robustness of the INSRTR strategy on proteins with diverse folds and biological functions, including enzymes, signaling mediators, DNA binders, transcriptional regulators, reporters, and antibody domains implemented as chimeric antigen receptors in T cells. Our findings highlight the potential of INSRTR as a powerful tool for precise control of protein function, advancing our understanding of biological processes and developing biotechnological and therapeutic interventions.
[前沿资讯 ] Spirulina shows potential as protein source for poultry feed 进入全文
Feed Navigator
A study underscores the potential of Spirulina sp. asa noel protein ingredient for poultry feeds,emphasizing its nutritional value, particularly itsprotein content, amino acid profile, protein solubility,and in vitro protein digestibility.
[学术文献 ] Impact of Dietary Probiotics on the Immune and Reproductive Physiology of Pubertal Male Japanese Quail (Coturnix coturnix japonica) Administered at the Onset of Pre-Puberty 进入全文
Probiotics and Antimicrobial Proteins
Fertility in males is dependent on the proper production of sperms involving the synchronization of numerous factors like oxidative stress, inflammatory processes, and hormonal regulation. Inflammation associated with oxidative stress is also known to impair sperm function. Nutritional factors like probiotics and prebiotics have the potential benefits to modulate these factors which may enhance male fertility. In the present study, immature male Japanese quail at the beginning of 3rd week were administered with Lactobacillus rhamnosus (L), Bifidobacterium longum (B), and mannan-oligosaccharides (M) through dietary supplementation in individual groups as well as in combinations like LB and MLB. Markers of oxidative stress including SOD and catalase were examined by native PAGE; inflammatory biomarkers (IL-1β, IL-10, and NFκB), apoptotic markers (caspase 3 and caspase 7), steroidal hormones, and their receptors estrogen receptor alpha (ERα) and beta (ERβ) were assessed in testis. The study reveals that dietary supplementation of 1% L, B, and M in combination significantly and positively increases the overall growth of immature male quail specifically testicular weight and gonadosomatic index (GSI). Furthermore, significant improvement in testicular cell size; increased steroidal hormones like testosterone, FSH, and LH levels; increase in SOD, catalase enzymes; decrease in apoptotic factors Caspase 3, Caspase 7 and immune system strength observed indicated by a decrease in expression of IL-1β, NFκB; and increase of IL-10 in testis when LBM was used in combination. These variations are attributed to the increase in testicular estrogen receptors alpha and beta, facilitated by the neuroendocrine gonadal axis, ultimately leading to improved male fertility. It can be concluded that the dietary supplementation in combination with L, B, and M enhances male fertility in immature quail by increased expression of estrogen receptors via gut microbiota modulation. It also sheds light on the potential use of these nutritional factors in avian species as therapeutic interventions to overcome low fertility problems in quail thereby benefitting the poultry industry.
