Sugars Will Eventually be Exported Transporters (SWEET) are a novel type of sugar transporter that plays crucial roles in multiple biological processes. From banana, for the first time, 25 SWEET ...genes which could be classified into four subfamilies were identified. Majority of MaSWEETs in each subfamily shared similar gene structures and conserved motifs. Comprehensive transcriptomic analysis of two banana genotypes revealed differential expression patterns of MaSWEETs in different tissues, at various stages of fruit development and ripening, and in response to abiotic and biotic stresses. More than 80% MaSWEETs were highly expressed in BaXi Jiao (BX, Musa acuminata AAA group, cv. Cavendish), in sharp contrast to Fen Jiao (FJ, M. acuminata AAB group) when pseudostem was first emerged. However, MaSWEETs in FJ showed elevated expression under cold, drought, salt, and fungal disease stresses, but not in BX. Interaction networks and co-expression assays further revealed that MaSWEET-mediated networks participate in fruit development signaling and abiotic/biotic stresses, which was strongly activated during early stage of fruit development in BX. This study provides new insights into the complex transcriptional regulation of SWEETs, as well as numerous candidate genes that promote early sugar transport to improve fruit quality and enhance stress resistance in banana.
Graphene oxide (GO) with abundant oxygen-containing groups was chosen as the support for the NH
3
-SCR catalysts. The as-prepared catalysts were systematically characterized to elucidate the effects ...of the surface properties and the morphological structure on catalytic activity by Raman, XPS, XRD, SEM, TEM, BET, NH
3
-TPD, and H
2
-TPR. It was found that compared with widely researched Graphene (GR), abundant oxygen-containing groups on the surface of GO provided the load sites and further promoted the dispersion of active component, which indicating the much more active sites exposed and further the better catalytic activity shown. Furthermore, the oxygen-containing groups like hydroxyl (-OH) and carboxyl (-COOH) could provide some Brønsted acid sites. After the loading of MnO
x
, the degree of graphitization of GO increased sharply, indicating the better electron transport and strong chemical interaction between GO and MnO
x
. Furthermore, the best load amount was found and the acidity was the main reason for the optimalizing performance on Mn-5/GO at low temperature. Besides, not only large specific area, but also outstanding redox performance and high dispersion of active component all contributed to the excellent performance of Mn-5/GO. Over all, this work formulated the advantages of GO worked as the support for SCR catalysts and significantly extended the cognition of GO and the selection basis of supports for the low-temperature NH
3
-SCR reaction.
Graphic abstract
The abundant oxygen-containing groups on the GO surface promoted the dispersion of the active material (MnO
x
) and also provided some weak acid sites.
COVID-19 has emerged as the most serious international pandemic in early 2020 and the lack of comprehensive knowledge in the recognition and transmission mechanisms of this virus hinders the ...development of suitable therapeutic strategies. The specific recognition during the binding of the spike glycoprotein (S protein) of coronavirus to the angiotensin-converting enzyme 2 (ACE2) in the host cell is widely considered the first step of infection. However, detailed insights on the underlying mechanism of dynamic recognition and binding of these two proteins remain unknown. In this work, molecular dynamics simulation and binding free energy calculation were carried out to systematically compare and analyze the receptor-binding domain (RBD) of six coronavirus’ S proteins. We found that affinity and stability of the RBD from SARS-CoV-2 under the binding state with ACE2 are stronger than those of other coronaviruses. The solvent-accessible surface area (SASA) and binding free energy of different RBD subunits indicate an “anchor-locker” recognition mechanism involved in the binding of the S protein to ACE2. Loop 2 (Y473-F490) acts as an anchor for ACE2 recognition, and Loop 3 (G496-V503) locks ACE2 at the other nonanchoring end. Then, the charged or long-chain residues in the β-sheet 1 (N450-F456) region reinforce this binding. The proposed binding mechanism was supported by umbrella sampling simulation of the dissociation process. The current computational study provides important theoretical insights for the development of new vaccines against SARS-CoV-2.
Constipation is a major complications of diabetes mellitus. With the accelerating prevalence of diabetes worldwide and an aging population, there is considerable research interest regarding the ...altered function and structure of the gastrointestinal tract in diabetic patients. Despite current advances in hyperglycemic treatment strategies, the specific pathogenesis of diabetic constipation remains unknown. Patients with constipation, may be reluctant to eat regularly, which may worsen glycemic control and thus worsen symptoms associated with underlying diabetic bowel disease. This paper presents a review of the complex relationship between diabetes and constipation, exploring the morphological alterations and biomechanical remodeling associated with intestinal motility dysfunction, as well as alterations in intestinal neurons, cellular signaling pathways, and oxidative stress. Further studies focusing on new targets that may play a role in the pathogenesis of diabetic constipation may, provide new ideas for the development of novel therapies to treat or even prevent diabetic constipation.
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•DM-induced myopathic effects, colonic neuropathy, and mucosal absorption can lead to changes in colonic sensory and motor responses.•DM alters the intestinal flora, impairs local neurotransmitters and hormone release.•Constipation in DM are associated with intracellular signaling pathways in enterocytes.•DM increases oxidative stress, impairs the contractile and diastolic responses of colonic circular muscle strips.
Intramural hematoma (IMH) and Aortic dissection (AD) have overlapping features. The aim of this study was to explore the differences between them by comparing the clinical manifestations and imaging ...features of patients with acute Stanford type B IMH-like lesions and acute Stanford type B AD (ATBAD).
This study retrospectively analysed the clinical and computed tomography angiography (CTA) imaging data of 42 IMH-like lesions patients with ulcer-like projection (ULP) and 38 ATBAD patients, and compared their clinical and imaging features.
(1) The IMH-like lesions patients were older than the ATBAD patients (64.2 ± 11.5 vs. 50.9 ± 12.2 years, P < 0.001). The D-dimer level in the IMH-like lesions group was significantly higher than that in the ATBAD group (11.2 ± 3.6 vs. 9.2 ± 4.5 mg/L, P < 0.05). The incidence rate of back pain was significantly higher in the ATBAD group than in the IMH-like lesions group (71.1% vs. 26.2%, P < 0.05). (2) The ULPs of IMH-like lesions and the intimal tears of ATBAD were concentrated in zone 4 of the descending thoracic aorta. The ULPs of IMH-like lesions and the intimal tears of ATBAD were mainly in the upper quadrant outside the lumen (64.3% vs. 65.8%, P > 0.05). (3) The maximum diameter of the ULPs in IMH-like lesions was smaller than that of the intimal tears in ATBAD (7.4 ± 3.4 vs. 10.8 ± 6.8 mm, P = 0.005). The lumen compression ratio in the ULPs plane and the maximum compression ratio of the aortic lumen in the IMH-like lesions group were smaller than that in the ADBAD group (P < 0.05). Fewer aortic segments were involved in IMH-like lesions patients than in ATBAD patients (5.6 ± 2.2 vs. 7.1 ± 1.9 segments, P < 0.005). The IMH-like lesions group had less branch involvement than that of the ATBAD group (P < 0.001).
The degree of intimal tears, lumen compression ratio, extent of lesion involvement, and impact on branch arteries in ATBAD are more severe than that of IMH-like lesions. But for the ULPs of IMH-like lesions and intimal tears of ATBAD, they have astonishing similarities in the location of the partition and the lumen quadrant, we have reason to believe that intimal tear is the initial factor in the pathogenesis of this kind of disease, and their clinical and imaging manifestations overlap, but the severity is different. Concerning similarities between these two conditions, these two may be a spectrum of one disease.
Lung infection is a common complication induced by stroke and seriously affects the prognosis and life quality of patients. However, effective therapeutic strategies are still lacking. In the present ...study, the herb formula GCis was confirmed to prevent pulmonary infection induced by intracerebral hemorrhage (ICH). The animal model of lung infection induced by ICH, GCis (Ginseng Radix et Rhizoma, Aconiti Lateralis Radix Praeparata, and Cistanches Herba) was orally administrated every day for 7 days. Lung microbial biomass and pathological results showed that the GCis formula pretreatment significantly reduced lung bacterial biomass and alleviated pathological abnormalities. These results indicated that the GCis formula has a clear pharmacological effect on preventing lung infection induced by ICH. Immunosuppression induced by ICH seemed to be the main mechanism of lung infection. Our results showed that the spleen and thymus indexes, WBC, and LY% contents were significantly increased in the GCis formula group. Moreover, bone marrow cells were further analyzed by transcriptome sequencing, and GO and KEGG enrichment analysis results showed that immune function was the main pathway enriched by differential genes after GCis formula intervention. More importantly, our results showed that GCis pretreatment had no significant effect on the mRNA expression of IL-1β, IL-6, and TNF-α in the brain. These results indicated that the GCis formula could enhance immunity after ICH. The intestinal barrier function was further investigated in the present study, considering the origin of the source of infection. Our results showed that the mRNA expressions of intestinal ZO-1, SIgA, and MUC2 were significantly increased, villi structure was intact, inflammatory cell infiltration was reduced, and goblet cell number was increased after GCis formula treatment. These results suggest that the GCis formula can enhance the intestinal mucosal immune barrier. This study provides a herb formula (GCis) that could enhance peripheral immunity and intestinal mucosal immune barrier to prevent pulmonary infection induced by ICH. It would be beneficial in the prevention of severe clinical infections.
β-amylase (BAM) is an important enzyme involved in conversion of starch to maltose in multiple biological processes in plants. However, there is currently insufficient information on the BAM gene ...family in the important fruit crop banana. This study identified 16 BAM genes in the banana genome. Phylogenetic analysis showed that MaBAMs were classified into four subfamilies. Most MaBAMs in each subfamily shared similar gene structures. Conserved motif analysis showed that all identified MaBAM proteins had the typical glyco hydro 14 domains. Comprehensive transcriptomic analysis of two banana genotypes revealed the expression patterns of MaBAMs in different tissues, at various stages of fruit development and ripening, and in responses to abiotic stresses. Most MaBAMs showed strong transcript accumulation changes during fruit development and late-stage ripening. Some MaBAMs showed significant changes under cold, salt, and osmotic stresses. This finding indicated that MaBAMs might be involved in regulating fruit development, ripening, and responses to abiotic stress. Analysis of five hormone-related and seven stress-relevant elements in the promoters of MaBAMs further revealed that BAMs participated in various biological processes. This systemic analysis provides new insights into the transcriptional characteristics of the BAM genes in banana and may serve as a basis for further functional studies of such genes.
Enzyme thermostability is an important parameter for estimating its industrial value. However, most naturally produced enzymes are incapable of meeting the industrial thermostability requirements. ...Software programs can be utilized to predict protein thermostability. Despite the fast-growing number of programs designed for this purpose; few provide reliable applicability because they do not account for thermodynamic weaknesses. Aspartic proteases are widely used in industrial processing; however, their thermostability is not able to meet the large-scale production requirements. In this study, through analyzing structural characteristics and modifying thermostability using prediction software programs, we improved the thermostability of pepsin, a representative aspartic protease. Based on the structural characteristics of pepsin and the experimental results of mutations predicted by several energy-based prediction software programs, it was found that the majority of pepsin’s thermodynamic weaknesses lie on its flexible regions on the surface. Using computational design, mutations were made based on the predicted sites of thermodynamic weakness. As a result, the half-lives of mutants D52N and S129A at 70°C were increased by 200.0 and 66.3%, respectively. Our work demonstrated that in the effort of improving protein thermostability, identification of structural weaknesses with the help of computational design, could efficiently improve the accuracy of protein rational design.
Chronic diseases, such as hypertension, cause great harm to human health. Conventional drugs have promising therapeutic effects, but also cause significant side effects. Food-sourced ...angiotensin-converting enzyme (ACE) inhibitory peptides are an excellent therapeutic alternative to pharmaceuticals, as they have fewer side effects. However, there is no systematic and effective screening method for ACE inhibitory peptides, and the lack of understanding of the sequence characteristics and molecular mechanism of these inhibitory peptides poses a major obstacle to the development of ACE inhibitory peptides. Through systematically calculating the binding effects of 160,000 tetrapeptides with ACE by molecular docking, we found that peptides with Tyr, Phe, His, Arg, and especially Trp were the characteristic amino acids of ACE inhibitory peptides. The tetrapeptides of WWNW, WRQF, WFRV, YYWK, WWDW, and WWTY rank in the top 10 peptides exhibiting significantly high ACE inhibiting behaviors, with IC
values between 19.98 ± 8.19 μM and 36.76 ± 1.32 μM. Salt bridges, π-π stacking, π-cations, and hydrogen bonds contributed to the high binding characteristics of the inhibitors and ACE. Introducing eight Trp into rabbit skeletal muscle protein (no Trp in wide sequence) endowed the protein with a more than 90% ACE inhibition rate, further suggesting that meat with a high content of Trp could have potential utility in hypertension regulation. This study provides a clear direction for the development and screening of ACE inhibitory peptides.
Food‐derived angiotensin I‐converting enzyme (ACE) inhibitory peptides represent a potential source of new antihypertensive. However, their characteristics and binding mechanisms were not well ...understood. In this study, novel energy calculation and experimentation were combined to elucidate the characteristics and mechanisms of ACE inhibitory tripeptides. ACE inhibitory activity of all 8,000 tripeptides was investigated by in silico experiments. IC50 values of the five top‐rated tripeptides ranged from 5.86 to 21.84 μM. Five hundred top‐ranked tripeptides were chosen for detailed structure–activity analysis, and a significant preference for aromatic amino acids at both C‐ and N‐terminus was found. By binding free energy analysis of nine representative tripeptides via MM/GBSA, electrostatic energy was found to be the leading energy that contributed to the binding of ACE with its high affinity tripeptides. Besides, S355, V380, and V518, three residues positioned around the classical binding pockets of ACE, also played a key role in ACE's binding. Therefore, for tripeptides, their binding pockets in ACE were redefined. In conclusion, the characteristics of ACE inhibitory peptides were more deeply illustrated by the thorough analysis of all tripeptides. The energy analysis allows a better understanding of the binding mechanisms of ACE inhibitory peptides, which could be used to redesign the ACE inhibitors for stronger inhibitory activity.
The characteristics of C‐ and N‐terminus of ACE inhibitory tripeptides were investigated. Electrostatic energy contributed to the binding of ACE with its high affinity tripeptides.
S355, V380, and V518 played a key role ACE’s binding with tripeptides.
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