Science China Life Sciences - The outbreak of coronavirus disease 2019 (COVID-19) caused by SARS-CoV-2 has created a global health crisis. SARS-CoV-2 infects varieties of tissues where the known... 相似文献
We constructed a recombinant oral GLP-1 analogue in Lactococcus lactis (L. lactis) and evaluated its physiological functions.
Results
In silico docking suggested the alanine at position 8 substituted with serine (A8SGLP-1) reduced binding of DPP4, which translated to reduced cleavage by DPP4 with minimal changes in stability. This was further confirmed by an in vitro enzymatic assay which showed that A8SGLP-1 significantly increased half-life upon DPP4 treatment. In addition, recombinant L. lactis (LL-A8SGLP-1) demonstrated reduced fat mass with no changes in body weight, significant improvement of random glycemic control and reduced systemic inflammation compared with WT GLP-1 in db/db mice.
Conclusion
LL-A8SGLP-1 adopted in live biotherapeutic products reduce blood glucose in db/db mice without affecting its function.
Chronic high glucose levels lead to the formation of advanced glycation end-products (AGEs) as well as AGE precursors, such as methylglyoxal (MG) and glyoxal, via non-enzymatic glycation reactions in patients with diabetic mellitus. Glyoxalase 1 (GLO-1) detoxifies reactive dicarbonyls that form AGEs. To investigate the interaction between AGEs and GLO-1 in mesangial cells (MCs) under diabetic conditions, AGE levels and markers of oxidative stress were measured in GLO-1-overexpressing MCs (GLO-1-MCs) cultured in high glucose. Furthermore, we also examined levels of high glucose-induced apoptosis in GLO-1-MCs. In glomerular MCs, high glucose levels increased the formation of both MG and argpyrimidine (an MG-derived adduct) as well as GLO-1 expression. GLO-1-MCs had lower intracellular levels of MG accumulation, 8-hydroxy-deoxyguanosine (an oxidative DNA damage marker), 4-hydroxyl-2-nonenal (a lipid peroxidation product), and nitrosylated protein (a marker of oxidative-nitrosative stress) compared to control cells. Expression of mitochondrial oxidative phosphorylation complexes I, II, and III was also decreased in GLO-1-MCs. Furthermore, fewer GLO-1-MCs showed evidence of apoptosis as determined by terminal deoxynucleotidyl transferase-mediated dUTP nick labeling assay, and activation of both poly (ADP-ribose) polymerase 1 cleavage and caspase-3 was lower in GLO-1-MCs than in control cells cultured in high glucose. These results suggest that GLO-1 plays a role in high glucose-mediated signaling by reducing MG accumulation and oxidative stress in diabetes mellitus. 相似文献
The Gram-positive bacterium Clavibacter michiganensis subsp. michiganensis is the causal agent of canker disease in tomato. Because it is very important to control newly introduced inoculum sources from commercial materials, the specific detection of this pathogen in seeds and seedlings is essential for effective disease control. In this study, a novel and efficient assay for the detection and quantitation of C. michiganensis subsp. michiganensis in symptomless tomato and red pepper seeds was developed. A pair of polymerase chain reaction (PCR) primers (Cmm141F/R) was designed to amplify a specific 141 bp fragment on the basis of a ferredoxin reductase gene of C. michiganensis subsp. michiganensis NCPPB 382. The specificity of the primer set was evaluated using purified DNA from 16 isolates of five C. michiganensis subspecies, one other Clavibacter species, and 17 other reference bacteria. The primer set amplified a single band of expected size from the genomic DNA obtained from the C. michiganensis subsp. michiganensis strains but not from the other C. michiganensis subspecies or from other Clavibacter species. The detection limit was a single cloned copy of the ferredoxin reductase gene of C. michiganensis subsp. michiganensis. In conclusion, this quantitative direct PCR assay can be applied as a practical diagnostic method for epidemiological research and the sanitary management of seeds and seedlings with a low level or latent infection of C. michiganensis subsp. michiganensis. 相似文献
Recent studies have demonstrated that cargo exit from the endoplasmic reticulum (ER) may be directed by ER export motifs recognized by components of the coat protein II (COPII) vesicles. However, little is known about ER export motifs and vesicle targeting of the G protein-coupled receptor (GPCR) superfamily. Here, we have demonstrated that a triple Arg (3R) motif in the third intracellular loop functions as a novel ER export signal for α(2B)-adrenergic receptor (α(2B)-AR). The 3R motif mediates α(2B)-AR interaction with Sec24C/D and modulates ER exit, cell surface transport and function of α(2B)-AR. Furthermore, export function of the 3R motif is independent of its position within α(2B)-AR and can be conferred to CD8 glycoprotein. These data provide the first evidence implicating that export of GPCRs is controlled by code-directed interactions with selective components of the COPII transport machinery. 相似文献
The inhibitory receptor programmed death-1 (PD-1) is present on CD8(+) T cells in chronic hepatitis C virus (HCV), but expression patterns in spontaneously resolving infections are incompletely characterized. Here we report that PD-1 was usually absent on memory CD8(+) T cells from chimpanzees with resolved infections, but sustained low-level expression was sometimes observed in the absence of apparent virus replication. PD-1-positive memory T cells expanded and displayed antiviral activity upon reinfection with HCV, indicating conserved function. This animal model should facilitate studies of whether PD-1 differentially influences effector and memory T-cell function in resolved versus persistent human infections. 相似文献