Application of Packed-nanofibers Solid-phase Extraction for Determination of Rhodamine B in Sausage

A method for the determination of Rhodamine B in sausage was developed and validated. After extraction of Rhodamine B with acetonitrile from foodstuffs, a novel electrospun polymer nanofibers packed micro-column was used for cleaning and concentrating of the analyte in the sample. High performance liquid chromatography with fluorescence detection (HPLC-Flu) was used for the determination of Rhodamine B in the sample. The mobile phase was composed of 3.0 g L-1 phosphate buffer and methanol (3:7, volume ratio), and the pH was adjusted to 7. 0 with orthophosphoric acid. The results showed that the standard curve was linear over the validated concentrations range of 2-500 ng g-1, and the limit of detection (LOD) and the limit of quantitation (LOQ) for Rhodamine B spiked samples was 0. 2 ng g-1 and 0. 7 ng g-1, respectively. The average recoveries of Rhodamine B were 90.4% -94.3% for sausage, and the relative standard deviation of the method was from 1.7% to 3.8%. This proposed method was applied to real sample, and there was no Rhodamine B found in sausage

Impacts of Freshwater and Seawater Mixing on the Production and Decay of Virioplankton in a Subtropical Estuary

Abstract(#br)Virioplankton is an important component of the aquatic ecosystem and plays multiple ecological and biogeochemical roles. Although the spatial and temporal distributions and dynamics of virioplankton have been well investigated in riverine and marine environments, little is known about the dynamics and environmental controlling mechanisms of virioplankton in estuaries. In this study, viral abundance, production and decay were examined in the Pearl River Estuary (PRE), one of the largest estuaries in China. The influences of freshwater and seawater mixing on viral ecological dynamics were evaluated with several cross-transplant experiments. In PRE, viral abundance, production and decay rates varied from 2.72 ± 0.09 to 27.5 ± 1.07 × 10 6 viruses ml −1 , 7.98 ± 2.33 to 16.27 ±..

Origins and stepwise expansion of R2R3-MYB transcription factors for the terrestrial adaptation of plants

The R2R3-MYB transcription factors play critical roles in various processes in embryophytes (land plants). Here, we identified genes encoding R2R3-MYB proteins from rhodophytes, glaucophytes, Chromista, chlorophytes, charophytes, and embryophytes. We classified the R2R3-MYB genes into three subgroups (I, II, and III) based on their evolutionary history and gene structure. The subgroup I is the most ancient group that includes members from all plant lineages. The subgroup II was formed before the divergence of charophytes and embryophytes. The subgroup III genes form a monophyletic group and only comprise members from land plants with conserved exon–intron structure. Each subgroup was further divided into multiple clades. The subgroup I can be divided into I-A, I-B, I-C, and I-D. The I-A, I-B, and I-C are the most basal clades that have originated before the divergence of Archaeplastida. The I-D with the II and III subgroups form a monophyletic group, containing only green plants. The II and III subgroups form another monophyletic group with Streptophyta only. Once on land, the subgroup III genes have experienced two rounds of major expansions. The first round occurred before the origin of land plants, and the second round occurred after the divergence of land plants. Due to significant gene expansion, the subgroup III genes have become the predominant group of R2R3-MYBs in land plants. The highly unbalanced pattern of birth and death evolution of R2R3-MYB genes indicates their important roles in the successful adaptation and massive radiation of land plants to occupy a multitude of terrestrial environments

High-fat diets enhance and delay ursodeoxycholic acid absorption but elevate circulating hydrophobic bile salts

Background: Ursodeoxycholic acid (UDCA) is a natural drug essential for the treatment of cholestatic liver diseases. The food effects on the absorption of UDCA and the disposition of circulating bile salts remain unclear despite its widespread global uses. This study aims to investigate the effects of high-fat (HF) diets on the pharmacokinetics of UDCA and disclose how the circulated bile salts were simultaneously perturbed.Methods: After an overnight fast, a cohort of 36 healthy subjects received a single oral dose (500 mg) of UDCA capsules, and another cohort of 31 healthy subjects received the same dose after consuming a 900 kcal HF meal. Blood samples were collected from 48 h pre-dose up to 72 h post-dose for pharmacokinetic assessment and bile acid profiling analysis.Results: The HF diets significantly delayed the absorption of UDCA, with the Tmax of UDCA and its major metabolite, glycoursodeoxycholic acid (GUDCA), changing from 3.3 h and 8.0 h in the fasting study to 4.5 h and 10.0 h in the fed study, respectively. The HF diets did not alter the Cmax of UDCA and GUDCA but immediately led to a sharp increase in the plasma levels of endogenous bile salts including those hydrophobic ones. The AUC0–72h of UDCA significantly increased from 25.4 μg h/mL in the fasting study to 30.8 μg h/mL in the fed study, while the AUC0–72h of GUDCA showed no difference in both studies. As a result, the Cmax of total UDCA (the sum of UDCA, GUDCA, and TUDCA) showed a significant elevation, while the AUC0–72h of total UDCA showed a slight increase without significance in the fed study compared to the fasting study.Conclusion: The HF diets delay UDCA absorption due to the extension of gastric empty time. Although UDCA absorption was slightly enhanced by the HF diets, the beneficial effect may be limited in consideration of the simultaneous elevation of circulating hydrophobic bile salts

Risk factors of oncogenic HPV infection in HIV-positive men with anal condyloma acuminata in Shenzhen, Southeast China: a retrospective cohort study

BackgroundHuman immunodeficiency virus (HIV)-positive patients with anal condyloma acuminata (CA) present an increased risk of anal cancer progression associated with oncogenic human papillomavirus (HPV) infection. It is essential to explore determinants of anal infection by oncogenic HPV among HIV-positive patients with CA.MethodsA retrospective cohort study was performed in HIV-positive patients with CA between January 2019 to October 2021 in Shenzhen, Southeast China. Exfoliated cells were collected from CA lesions and the anal canal of HPV genotypes detected by fluorescence PCR. Unconditional logistic regression analysis was used to probe associations of independent variables with oncogenic HPV infection.ResultsAmong HIV-positive patients with CA, the most prevalent oncogenic genotypes were HPV52 (29.43%), HPV16 (28.93%), HPV59 (19.20%), and HPV18 (15.96%). Risk of oncogenic HPV infection increased with age at enrollment (COR: 1.04, 95% CI: 1.01–1.07, p = 0.022). In the multivariable analysis, age ≥ 35 years (AOR: 2.56, 95% CI: 1.20–5.70, p = 0.02) and history of syphilis (AOR: 3.46, 95% CI: 1.90–6.79, p < 0.01) were independent risk factors statistically associated with oncogenic HPV infection. History of syphilis (AOR: 1.72, 95% CI: 1.08–2.73, p < 0.02) was also an independent risk factor statistically associated with HPV16 or HPV18 infection.ConclusionIn clinical practice, HIV-positive CA patients aged ≥35 years or with a history of syphilis should carry out HR-HPV testing and even anal cancer-related examinations to prevent the occurrence of anal cancer

Sr, Fe Co-doped Perovskite Oxides With High Performance for Oxygen Evolution Reaction

Developing efficient and earth-abundant electrocatalysts for the oxygen evolution reaction (OER) is still a big challenge. Here, perovskite La0.4Sr0.6Ni0.5Fe0.5O3 nanoparticles were rationally designed and synthesized by the sol-gel method with an average size around 25 nm, and it has a remarkable intrinsically activity and stability in 1 M KOH solution. Compared with other perovskite (LaNiO3, LaFeO3, and LaNi0.5Fe0.5O3) catalysts, La0.4Sr0.6Ni0.5Fe0.5O3 exhibits superior OER performance, smaller tafel slope and lower overpotential. The high electrochemical performance of La0.4Sr0.6Ni0.5Fe0.5O3 is attributed to its optimized eg filling (~1.2), as well as the excellent conductivity. This study demonstrates co-doping process is an effective way for increasing the intrinsic catalytic activity of the perovskite

Rapid discovery and crystallography study of highly potent and selective butylcholinesterase inhibitors based on oxime-containing libraries and conformational restriction strategies

22 p.-9 fig.-8 tab.Butyrylcholinesterase is regarded as a promising drug target in advanced Alzheimer’s disease. In order to identify highly selective and potent BuChE inhibitors, a 53-membered compound library was constructed via the oxime-based tethering approach based on microscale synthesis. Although A2Q17 and A3Q12 exhibited higher BuChE selectivity versus acetylcholinesterase, the inhibitory activities were unsatisfactory and A3Q12 did not inhibit Aβ1-42 peptide self-induced aggregation. With A2Q17 and A3Q12 as leads, a novel series of tacrine derivatives with nitrogen-containing heterocycles were designed based on conformation restriction strategy. The results demonstrated that 39 (IC50 = 3.49 nM) and 43 (IC50 = 7.44 nM) yielded much improved hBuChE inhibitory activity compared to the lead A3Q12 (IC50 = 63 nM). Besides, the selectivity indexes (SI = AChE IC50 / BChE IC50) of 39 (SI = 33) and 43 (SI = 20) were also higher than A3Q12 (SI = 14). The results of the kinetic study showed that 39 and 43 exhibited a mixed-type inhibition against eqBuChE with respective Ki values of 1.715 nM and 0.781 nM. And 39 and 43 could inhibit Aβ1-42 peptide self-induced aggregation into fibril. X-ray crystallography structures of 39 or 43 complexes with BuChE revealed the molecular basis for their high potency. Thus, 39 and 43 are deserve for further study to develop potential drug candidates for the treatment of Alzheimer’s disease.We gratefully acknowledge financial support from the Shandong Provincial Key Research and Development Project (No. 2019JZZY021011), Science Foundation for Outstanding Young Scholars of Shandong Province (ZR2020JQ31), Foreign Cultural and Educational Experts Project (GXL20200015001), Qilu Young Scholars Program of Shandong University, Distinguished Young and Middle-aged Scholar of Shandong University, the Taishan Scholar Program at Shandong Province, and MINECO (Grants SAF2016-76693-R to A.M), F.C., F.N. and X.B. were supported by the French Ministry of Armed Forces (Direction Générale de l'Armement and Service de Santé des Armées, NBC-5-C-4210). Authors would like to thank the ESRF for long-term beamtime access (MX2329 IBS BAG).Peer reviewe

Role of the ISKpn element in mediating mgrB gene mutations in ST11 hypervirulent colistin-resistant Klebsiella pneumoniae

BackgroundColistin has emerged as a last-resort therapeutic against antibiotic-resistant bacterial infections, particularly those attributed to carbapenem-resistant Enterobacteriaceae (CRE) like CRKP. Yet, alarmingly, approximately 45% of multidrug-resistant Klebsiella pneumoniae strains now manifest resistance to colistin. Through our study, we discerned that the synergy between carbapenemase and IS elements amplifies resistance in Klebsiella pneumoniae, thereby narrowing the existing therapeutic avenues. This underscores the instrumental role of IS elements in enhancing colistin resistance through mgrB disruption.MethodsFrom 2021 to 2023, 127 colistin-resistant Klebsiella pneumoniae isolates underwent meticulous examination. We embarked on an exhaustive genetic probe, targeting genes associated with both plasmid-mediated mobile resistance-encompassing blaKPC, blaNDM, blaIMP, blaVIM, blaOXA-48-like, and mcr-1 to mcr-8-and chromosome-mediated resistance systems, including PhoP/Q, PmrA/B, and mgrB. PCR amplification revealed the presence of virulence-associated genes from the pLVPK plasmid, such as rmpA, rmpA2, iucA, iroB, and peg344. mgrB sequencing was delegated to Sangon Biotech, Shanghai, and the sequences procured were validated using BLAST. Our search for IS elements was navigated through the IS finder portal. Phenotypically, we harnessed broth microdilution (BMD) to ascertain the MICs of colistin. To sketch the clonal lineage of mgrB-mutated CoR-Kp isolates, sophisticated methodologies like MLST and PFGE were deployed. S1-PFGE unraveled the intrinsic plasmids in these isolates. Our battery of virulence assessment techniques ranged from the string test and capsular serotyping to the serum killing assay and the Galleria mellonella larval infection model.ResultsAmong the 127 analyzed isolates, 20 showed an enlarged mgrB PCR amplicon compared to wild-type strains. These emerged over a three-year period: three in 2021, thirteen in 2022, and four in 2023. Antimicrobial susceptibility tests revealed that these isolates consistently resisted several drugs, notably TCC, TZP, CAZ, and COL. Additionally, 85% resisted both DOX and TOB. The MICs for colistin across these strains ranged between 16 to 64 mg/L, with a median of 40 mg/L. From a genetic perspective, MLST unanimously categorized these mgrB-mutated CoR-hvKp isolates as ST11. PFGE further delineated them into six distinct clusters, with clusters A and D being predominant. This distribution suggests potential horizontal and clonal genetic transmission. Intriguingly, every mgrB-mutated CoR-hvKP isolate possessed at least two virulence genes akin to the pLVPK-like virulence plasmid, with iroB and rmpA2 standing out. Their virulence was empirically validated both in vitro and in vivo. A pivotal discovery was the identification of three distinct insertion sequence (IS) elements within or near the mgrB gene. These were:ISKpn26 in eleven isolates, mainly in cluster A, with various insertion sites including +74, +125, and an upstream −35.ISKpn14 in four isolates with insertions at +93, −35, and two upstream at −60.IS903B present in five isolates, marking positions like +74, +125, +116, and −35 in the promoter region. These diverse insertions, spanning six unique locations in or near the mgrB gene, underscore its remarkable adaptability.ConclusionOur exploration spotlights the ISKpn element’s paramount role in fostering mgrB gene mutations in ST11 hypervirulent colistin-resistant Klebsiella pneumoniae. Employing MLST and PFGE, we unearthed two primary genetic conduits: clonal and horizontal. A striking observation was the ubiquitous presence of the KPC carbapenemase gene in all the evaluated ST11 hypervirulent colistin-resistant Klebsiella pneumoniae strains, with a majority also harboring the NDM gene. The myriad mgrB gene insertion locales accentuate its flexibility and the overarching influence of IS elements, notably the pervasive IS5-like variants ISKpn26 and IS903B. Our revelations illuminate the escalating role of IS elements in antibiotic resistance within ST11 hypervirulent colistin-resistant Klebsiella pneumoniae, advocating for innovative interventions to counteract these burgeoning resistance paradigms given their profound ramifications for prevailing treatment modalities