Anthropogenic environments have been implicated in enrichment and exchange of antibiotic resistance genes and bacteria. Here we study the impact of confined and controlled swine farm environments on ...temporal changes in the gut microbiome and resistome of veterinary students with occupational exposure for 3 months. By analyzing 16S rRNA and whole metagenome shotgun sequencing data in tandem with culture-based methods, we show that farm exposure shapes the gut microbiome of students, resulting in enrichment of potentially pathogenic taxa and antimicrobial resistance genes. Comparison of students' gut microbiomes and resistomes to farm workers' and environmental samples revealed extensive sharing of resistance genes and bacteria following exposure and after three months of their visit. Notably, antibiotic resistance genes were found in similar genetic contexts in student samples and farm environmental samples. Dynamic Bayesian network modeling predicted that the observed changes partially reverse over a 4-6 month period. Our results indicate that acute changes in a human's living environment can persistently shape their gut microbiota and antibiotic resistome.
This work reported the grain growth kinetics of high‐entropy diboride (HEB) and HEB‐SiC ceramics containing 10, 20, and 30 vol% SiC during heat treatment at 1800°C. The coarsening of HEB phase ...occurred in the four kinds of ceramics during heat treatment, especially in HEB ceramics. The kinetic analysis showed that the grain growth of HEB phase in HEB and HEB‐SiC ceramics is controlled by interface‐controlled kinetics and grain‐boundary pinning, respectively. The growth rate constant of HEB grains is lower than ZrB2, which is related to the low grain‐boundary energy and the sluggish diffusion effect in dynamics of high‐entropy materials. The growth rate of matrix phase in HEB‐SiC ceramics is similar to that in ZrB2–SiC ceramics, indicating that the pinning effect of the SiC second‐phase played the dominant role in inhibiting the grain growth of the high‐entropy matrix phase and disguised the sluggish diffusion effect. This study reveals that the grain growth inhibition through sluggish diffusion effect in a high‐entropy ceramic system may be magnified by the possible existence of segregated second‐phase particles located at the grain boundaries.
As new 2D layered nanomaterials, Bi2O2Se nanoplates have unique semiconducting properties that can benefit biomedical applications. Herein, a facile top‐down approach for the synthesis of Bi2O2Se ...quantum dots (QDs) in a solution is described. The Bi2O2Se QDs with a size of 3.8 nm and thickness of 1.9 nm exhibit a high photothermal conversion coefficient of 35.7% and good photothermal stability. In vitro and in vivo assessments demonstrate that the Bi2O2Se QDs possess excellent photoacoustic (PA) performance and photothermal therapy (PTT) efficiency. After systemic administration, the Bi2O2Se QDs accumulate passively in tumors enabling efficient PA imaging of the entire tumors to facilitate imaging‐guided PTT without obvious toxicity. Furthermore, the Bi2O2Se QDs which exhibit degradability in aqueous media not only have sufficient stability during in vivo circulation to perform the designed therapeutic functions, but also can be discharged harmlessly from the body afterward. The results reveal the great potential of Bi2O2Se QDs as a biodegradable multifunctional agent in medical applications.
2D Bi2O2Se quantum dots (QDs) are synthesized by a facile top‐down approach. Boasting large photothermal conversion efficiency and excellent photoacoustic performance as well as suitable biodegradability, the Bi2O2Se QDs facilitate photoacoustic imaging of the entire tumors in photothermal cancer therapy. The semiconducting QDs are promising as a near‐infrared‐triggered theranostic agent in cancer therapy.
Abstract
Despite remarkable recent advances in transition-metal-catalyzed C(sp
3
)−C cross-coupling reactions, there remain challenging bond formations. One class of such reactions include ...the formation of
tertiary
-C(sp
3
)−C bonds, presumably due to unfavorable steric interactions and competing isomerizations of tertiary alkyl metal intermediates. Reported herein is a Ni-catalyzed migratory 3,3-difluoroallylation of unactivated alkyl bromides at remote tertiary centers. This approach enables the facile construction of otherwise difficult to prepare all-carbon quaternary centers. Key to the success of this transformation is an unusual remote functionalization via chain walking to the most sterically hindered tertiary C(sp
3
) center of the substrate. Preliminary mechanistic and radical trapping studies with primary alkyl bromides suggest a unique mode of tertiary C-radical generation through chain-walking followed by Ni–C bond homolysis. This strategy is complementary to the existing coupling protocols with
tert
-alkyl organometallic or -alkyl halide reagents, and it enables the expedient formation of quaternary centers from easily available starting materials.
Black phosphorus (BP), a burgeoning elemental 2D semiconductor, has aroused increasing scientific and technological interest, especially as a channel material in field‐effect transistors (FETs). ...However, the intrinsic instability of BP causes practical concern and the transistor performance must also be improved. Here, the use of metal‐ion modification to enhance both the stability and transistor performance of BP sheets is described. Ag+ spontaneously adsorbed on the BP surface via cation–π interactions passivates the lone‐pair electrons of P thereby rendering BP more stable in air. Consequently, the Ag+‐modified BP FET shows greatly enhanced hole mobility from 796 to 1666 cm2 V−1 s−1 and ON/OFF ratio from 5.9 × 104 to 2.6 × 106. The mechanisms pertaining to the enhanced stability and transistor performance are discussed and the strategy can be extended to other metal ions such as Fe3+, Mg2+, and Hg2+. Such stable and high‐performance BP transistors are crucial to electronic and optoelectronic devices. The stability and semiconducting properties of BP sheets can be enhanced tremendously by this novel strategy.
A simple and effective metal‐ion modification strategy based on cation–π interactions is applied to black phosphorus to enhance both its air stability and its transistor performance. Such stable and high‐performance black‐phosphorus transistors, which are enhanced tremendously by this novel strategy, have large potential in electronic and optoelectronic devices.
Septic cardiomyopathy is characterized by impaired contractive function with mitochondrial dysregulation. Songorine is a typical active C20-diterpene alkaloid from the lateral root of Aconitum ...carmichaelii, which has been used for the treatment of heart failure. This study investigated the protective role of songorine in septic heart injury from the aspect of mitochondrial biogenesis. Songorine (10, 50 mg/kg) protected cardiac contractive function against endotoxin insult in mice with Nrf2 induction. In cardiomyocytes, lipopolysaccharide (LPS) evoked mitochondrial reactive oxygen species (ROS) production and redistributed STIM1 to interact with Orai1 for the formation of calcium release-activated calcium (CRAC) channels, mediating calcium influx, which were prevented by songorine, likely due to ROS suppression. Songorine activated Nrf2 by promoting Keap1 degradation, having a contribution to enhancing antioxidant defenses. When LPS shifted metabolism away from mitochondrial oxidative phosphorylation (OXPHOS) in cardiomyocytes, songorine upregulated mitochondrial genes involved in fatty acid β-oxidation, tricarboxylic acid (TCA) cycle and electron transport chain in a manner dependent on Nrf2, resultantly protecting the capability of OXPHOS. Songorine increased luciferase report gene activities of nuclear respiratory factor-1 (Nrf1) and mitochondrial transcription factor A (Tfam) dependently on Nrf2, indicative of the regulation of Nrf2/ARE and NRF1 signaling cascades. Songorine promoted PGC-1α binding to Nrf2, and the cooperation was required for songorine to activate Nrf2/ARE and NRF1 for the control of mitochondrial quality and quantity. In support, the beneficial effects of songorine on cardioprotection and mitochondrial biogenesis were diminished by cardiac Nrf2 deficiency in mice subjected to LPS challenge. Taken together, these results showed that Nrf2 transcriptionally promoted mitochondrial biogenesis in cooperation with PGC-1α. Songorine activated Nrf2/ARE and NRF1 signaling cascades to rescue cardiomyocytes from endotoxin insult, suggesting that protection of mitochondrial biogenesis was a way for pharmacological intervention to prevent septic heart injury.
Display omitted
•Mitochondrial ROS increased calcium influx through CRAC channels.•Nrf2 interacted with PGC-1α to regulate mitochondrial biogenesis.•Songorine activated Nrf2 by promoting Keap1 degradation.•Songorine regulated Nrf2/ARE and PGC-1α cascades to protect cardiac function.
Both vitamin D3 (VD3) and zinc (Zn) are essential micronutrients to fish, and VD3 can regulate Zn uptake and metabolism in various animals. However, the interactive effect of VD3 and Zn on growth ...performance, Zn metabolism, and intestinal health remains largely unknown in fish. The study formulated four experimental diets to culture yellow catfish, i.e., basic VD3 addition without extra Zn addition (control), basic VD3 addition with extra Zn addition (Zn group), high VD3 addition without extra Zn addition (VD3 group), and high VD3 and Zn addition (Zn + VD3 group). Four experimental groups contain Zn and VD3 contents at 41.15 mg/kg + 1027 IU/kg (control), 94.77 mg/kg + 1033 IU/kg (Zn group), 41.04 mg/kg + 16,047 IU/kg (VD3 group), and 94.89 mg/kg + 16,109 IU/kg (Zn + VD3 group), respectively. The experiment continued for 10 weeks. Dietary Zn and VD3 interacted to affect specific growth rate (SGR), Zn content and mRNA expression of Zn metabolism (zip4, zip9, zip14, znt1, znt2, mtf-1, and mt), SUMOylation-relevant genes (sae1, ubc9, pias1, sumo1, senp2, and senp5), tight junction-relevant genes (claudin-4, zo1, zo2, zo3, and jam2a), antioxidant (nrf2 and cat) and inflammatory genes (il1b and il8). Compared to the control, high dietary Zn addition increased intestinal mRNA expression of zip4, znt1, znt2, mt, sae1, ubc9, pias1, sumo1, claudin4, zo1, zo2, and jam2a and il1b, and Zn contents, but decreased mRNA expression of zip9, senp2, senp5, nrf2 and cat. Compared to high Zn addition in the diets, Zn and VD3 co-addition increased SGR, Zn contents, and mRNA expression of zip4, znt1, znt2, mt, mtf-1, senp2, senp5, claudin4, zo1, zo2, zo3, jam2a, nrf2 and cat, but decreased mRNA expression of zip9, zip14, sae1, ubc9, pias1, sumo1 and il1b. Dietary Zn and VD3 co-addition interacted to influence Cu/Zn-SOD, CAT and GPx activities, T-AOC, MDA content. Compared to control, high dietary Zn addition decreased intestinal Cu/Zn-SOD, CAT, GPx activities and T-AOC but increased MDA content. Compared to extra Zn addition in the diets, Zn and VD3 co-addition increased Cu/Zn-SOD, CAT and GPx activities as well as T-AOC but decreased MDA content. Based on these observations, our study indicated that high dietary Zn addition influenced Zn metabolism and SUMOylation modification, damaged the tight junction, induced oxidative stress and inflammatory responses in the intestine, and dietary vitamin D3 addition promoted growth performance and alleviated high dietary Zn-induced negative effects on the intestine of yellow catfish.
Our study elucidated the innovative insights into the interaction of Zn and VD3 in fish, which provided the important references for dietary Zn and VD3 addition in aquafeeds.
•Dietary Zn and VD3 interacted to affect growth performance and Zn metabolism.•Dietary Zn and VD3 interacted to affect SUMOylation modification.•Zn and VD3 interacted to affect tight junction, oxidant stress and inflammation.•VD3 promoted growth and alleviated high dietary Zn-induced negative effects.
Recently, stimuli-responsive supramolecular gels have received significant attention because their properties can be modulated through external stimuli such as heat, light, electricity, magnetic ...fields, mechanical stress, pH, ions, chemicals and enzymes. Among these gels, stimuli-responsive supramolecular metallogels have shown promising applications in material science because of their fascinating redox, optical, electronic and magnetic properties. In this review, research progress on stimuli-responsive supramolecular metallogels in recent years is systematically summarized. According to external stimulus sources, stimuli-responsive supramolecular metallogels, including chemical, physical and multiple stimuli-responsive metallogels, are discussed separately. Moreover, challenges, suggestions and opportunities regarding the development of novel stimuli-responsive metallogels are presented. We believe the knowledge and inspiration gained from this review will deepen the current understanding of stimuli-responsive smart metallogels and encourage more scientists to provide valuable contributions to this topic in the coming decades.
Melatonin (MT) functions in removing reactive oxygen species (ROS) and delaying plant senescence, thereby acting as an antioxidant; however, the molecular mechanism underlying the specific action of ...MT is unclear. Herein, we used the mutant plants carrying the MT decomposition gene melatonin 3‐hydroxylase (M3H) in tomato to elucidate the specific mechanism of action of MT. SlM3H‐OE accelerated senescence by decreasing the content of endogenous MT in plants. SlM3H is a senescence‐related gene that positively regulates aging. MT inhibited the expression of the senescence‐related gene SlCV to scavenge ROS, induced stable chloroplast structure, and delayed leaf senescence. Simultaneously, MT weakened the interaction between SlCV and SlPsbO/SlCAT3, reduced ROS production in photosystem II, and promoted ROS elimination. In conclusion, MT regulates ROS homeostasis and delays leaf aging in tomato plants through SlCV expression modulation.
The Toll signaling pathway in Drosophila melanogaster regulates several immune-related functions, including the expression of antimicrobial peptide (AMP) genes. The canonical Toll receptor (Toll-1) ...is activated by the cytokine Spätzle (Spz-1), but Drosophila encodes eight other Toll genes and five other Spz genes whose interactions with one another and associated functions are less well-understood. Here, we conducted in vitro assays in the Drosophila S2 cell line with the Toll/interleukin-1 receptor (TIR) homology domains of each Toll family member to determine whether they can activate a known target of Toll-1, the promoter of the antifungal peptide gene drosomycin. All TIR family members activated the drosomycin promoter, with Toll-1 and Toll-7 TIRs producing the highest activation. We found that the Toll-1 and Toll-7 ectodomains bind Spz-1, -2, and -5, and also vesicular stomatitis virus (VSV) virions, and that Spz-1, -2, -5, and VSV all activated the promoters of drosomycin and several other AMP genes in S2 cells expressing full-length Toll-1 or Toll-7. In vivo experiments indicated that Toll-1 and Toll-7 mutants could be systemically infected with two bacterial species (Enterococcus faecalis and Pseudomonas aeruginosa), the opportunistic fungal pathogen Candida albicans, and VSV with different survival times in adult females and males compared with WT fly survival. Our results suggest that all Toll family members can activate several AMP genes. Our results further indicate that Toll-1 and Toll-7 bind multiple Spz proteins and also VSV, but they differentially affect adult survival after systemic infection, potentially because of sex-specific differences in Toll-1 and Toll-7 expression.
PDF
