High Prevalence of Colistin-Resistant Encoding Genes Carriage among Patients and Healthy Residents in Vietnam.

Background and Objectives: We aimed to investigate the carriage of colistin-resistant genes among both patients with a history of antibiotic exposure and apparently healthy adults with no recent healthcare contact. Materials and Methods: Stool swabs were collected from healthy people, and specimens were collected at the infection foci from the patients. Eleven primer/probe sets were used to perform the Multiplex Real-Time PCR assay with the QuantiNova Multiplex Probe PCR kit for screening the carriage of colistin-resistant genes (mcr-1 to mcr-10) and 16S rRNA gene as internal control. Results: In total, 86 patients and 96 healthy residents were included. Twenty two patients (25.9%) were positive with at least one colistin-resistance encoding gene. The mcr-1 gene was the most frequent (16.5%), followed by mcr-9, mcr-6, and mcr-4 genes, where the prevalence was 11.8%, 10.6%, and 9.4%, respectively. No patient was positive with mcr-3, mcr-7, and mcr-8 genes. Eight patients (9.4%) were positive with multiple colistin-encoding genes. Twenty-three healthy people (24.0%) were positive with at least one colistin-resistance encoding gene, and the mcr-10 gene was the most frequent (27.0%), followed by the mcr-1, mcr-8, and mcr-9 genes, where the prevalence was 24.3%, 21.6%, and 13.5%, respectively. No person was positive with the mcr-2 and mcr-5 genes. Conclusions: Our findings underscore the urgent need for enhanced surveillance, infection control measures, and stewardship interventions to mitigate the spread of colistin resistance in Vietnam.

Coscinoderines A-J: Trisubstituted Pyridinium-Containing Norterpenoids Isolated from Coscinoderma bakusi, a Tropical Marine Sponge.

Ten new norterpene alkaloids, coscinoderines A-J (1-10), were isolated from the marine sponge Coscinoderma bakusi. Each coscinoderine contains a 1,2,5-trisubstituted pyridinium moiety bearing a terpene unit at the C-2 position. Their structures were elucidated by analysis of NMR and HRMS data, and the absolute stereochemistry of 4 with a 2-methylbutyl group attached to the nitrogen was determined from a comparison of the calculated and measured ECD spectra. The isolation of coscinoderines expands the repertoire of pyridinium alkaloids isolated from marine sponges.

Optimizing Ultrasonic-Assisted and Microwave-Assisted Extraction Processes to Recover Phenolics and Flavonoids from Passion Fruit Peels.

This study optimized the ultrasonic-assisted extraction (UAE) and microwave-assisted extraction (MAE) processes to acquire phenolics and flavonoids from passion fruit peels using a mixture of ethanol, acetone, and water. An augmented simplex-centroid design was employed to find the suitable volume ratio among solvent ingredients to attain the highest extraction yield of phenolics and flavonoids. One-factor experiments were conducted to investigate the influence of UAE and MAE parameters on the recovery yield of phenolics and flavonoids before the two processes were optimized using Box-Behnken Design (BBD) models. The optimal UAE conditions for recovering phenolics and flavonoids from passion fruit peel powder (PFP) were 28 mL/g of liquid-to-solid ratio (LSR), 608 W of ultrasonic power, and 63 °C for 20 min to acquire total phenolic content (TPC) and total flavonoid content (TFC) at 39.38 mg of gallic acid equivalents per gram of dried basis (mg GAE/g db) and 25.79 mg of rutin equivalents per gram of dried basis (mg RE/g db), respectively. MAE conditions for attaining phenolics and flavonoids from PFP were 26 mL/g of LSR and 606 W of microwave power for 2 min to recover TPC and TFC at 17.74 mg GAE/g db and 8.11 mg RE/g db, respectively. The second-order kinetic model was employed to determine the UAE and MAE mechanism of TPC and TFC and the thermodynamic parameters of the extraction processes. The antioxidant activities of passion fruit peel extracts at optimal conditions were examined to compare the efficiency of UAE and MAE. This study establishes an effective approach for obtaining phenolics and flavonoids from passion fruit peels.

Differences between surfactant-free Au@Ag and CTAB-stabilized Au@Ag star-like nanoparticles in the preparation of nanoarrays to improve their surface-enhanced Raman scattering (SERS) performance.

In this study, we assessed the controlled synthesis and efficacy of surface-enhanced Raman scattering (SERS) on two distinct types of star-like Au@Ag core-shell nanoarrays. These nanoarrays were designed based on gold nanostars (AuNSs), which were synthesized with and without CTAB surfactant (AuNSs-CTAB and AuNSs-FS, respectively). The AuNS-FS nanoparticles were synthesized via a novel modification process, which helped overcome the previous limitations in the free-surfactant preparation of AuNSs by significantly increasing the number of branches, increasing the sharpness of the branches and minimizing the adsorption of the surfactant on the surface of AuNSs. Furthermore, the differences in the size and morphology of these AuNSs in the created nanoarrays were studied. To create the nanoarrays, a three-step method was employed, which involved the controlled synthesis of gold nanostars, covering them with a silver layer (AuNSs-FS@Ag and AuNSs-CTAB@Ag), and finally self-assembling the AuNS@Ag core-shelled nanoparticles via the liquid/liquid self-assembly method. AuNSs-FS@Ag showed higher ability in forming self-assembled nanoarrays than the nanoparticles prepared using CTAB, which can be attributed to the decrease in the repulsion between the nanoparticles at the interface. The nano-substrates developed with AuNSs-FS@Ag possessed numerous "hot spots" on their surface, resulting in a highly effective SERS performance. AuNSs-FS featured a significantly higher number of sharp branches than AuNSs-CTAB, making it the better choice for creating nanoarrays. It is worth mentioning that AuNSs-CTAB did not exhibit the same benefits as AuNSs-FS. The morphology of AuNSs with numerous branches was formed by controlling the seed boiling temperature and adding a specific amount of silver ions. To compare the SERS activity between the as-prepared nano-substrates, i.e., AuNS-CTAB@Ag and AuNS-FS@Ag self-assembled nanoarrays, low concentrations of crystal violet aqueous solution were characterized. The results showed that the developed AuNSs-FS@Ag could detect CV at trace concentrations ranging from 1.0 ng mL-1 to 10 ng mL-1 with a limit of detection (LOD) of 0.45 ng mL-1 and limit of quantification (LOQ) of 1.38 ng mL-1. The nano-substrates remained stable for 42 days with a decrease in the intensity of the characteristic Raman peaks of CV by less than 7.0% after storage. Furthermore, the spiking method could detect trace amounts of CV in natural water from the Dong Nai River with concentrations as low as 1 to 100 ng mL-1, with an LOD of 6.07 ng mL-1 and LOQ of 18.4 ng mL-1. This method also displayed good reproducibility with an RSD value of 5.71%. To better understand the impact of CTAB stabilization of the Au@Ag star-like nanoparticles on their surface-enhanced Raman scattering (SERS) performance, we conducted density functional theory (DFT) calculations. Our research showed that the preparation of AuNSs-FS@Ag via self-assembly is an efficient, simple, and fast process, which can be easily performed in any laboratory. Furthermore, the research and development results presented herein on nanoarrays have potential application in analyzing and determining trace amounts of organic compounds in textile dyeing wastewater.

A native conjugative plasmid confers potential selective advantages to plant growth-promoting Bacillus velezensis strain GH1-13.

The conjugative plasmid (pBV71) possibly confers a selective advantage to Bacillus velezensis strain GH1-13, although a selective marker gene is yet to be identified. Here we show that few non-mucoid wild-type GH1-13 cells are spontaneously converted to mucoid variants with or without the loss of pBV71. Mucoid phenotypes, which contain or lack the plasmid, become sensitive to bacitracin, gramicidin, selenite, and tellurite. Using the differences in antibiotic resistance and phenotype, we isolated a reverse complement (COM) and a transconjugant of strain FZB42 with the native pBV71. Transformed COM and FZB42p cells were similar to the wild-type strain GH1-13 with high antibiotic resistance and slow growth rates on lactose compared to those of mucoid phenotypes. RT-PCR analysis revealed that the expression of plasmid-encoded orphan aspartate phosphatase (pRapD) was coordinated with a new quorum-sensing (QS) cassette of RapF2-PhrF2 present in the chromosome of strain GH1-13, but not in strain FZB42. Multi-omics analysis on wild-type and plasmid-cured cells of strain GH1-13 suggested that the conjugative plasmid expression has a crucial role in induction of early envelope stress response that promotes cell morphogenesis, biofilm formation, catabolite repression, and biosynthesis of extracellular-matrix components and antibiotics for protection of host cell during exponential phase.

A Robotic Biopsy Endoscope with Magnetic 5-DOF Locomotion and a Retractable Biopsy Punch.

Capsule endoscopes (CEs) have emerged as an advanced diagnostic technology for gastrointestinal diseases in recent decades. However, with regard to robotic motions, they require active movability and multi-functionalities for extensive, untethered, and precise clinical utilization. Herein, we present a novel wireless biopsy CE employing active five degree-of-freedom locomotion and a biopsy needle punching mechanism for the histological analysis of the intestinal tract. A medical biopsy punch is attached to a screw mechanism, which can be magnetically actuated to extrude and retract the biopsy tool, for tissue extraction. The external magnetic field from an electromagnetic actuation (EMA) system is utilized to actuate the screw mechanism and harvest biopsy tissue; therefore, the proposed system consumes no onboard energy of the CE. This design enables observation of the biopsy process through the capsule's camera. A prototype with a diameter of 12 mm and length of 30 mm was fabricated with a medical biopsy punch having a diameter of 1.5 mm. Its performance was verified through numerical analysis, as well as in-vitro and ex-vivo experiments on porcine intestine. The CE could be moved to target lesions and obtain sufficient tissue samples for histological examination. The proposed biopsy CE mechanism utilizing punch biopsy and its wireless extraction-retraction technique can advance untethered intestinal endoscopic capsule technology at clinical sites.

A wireless tattooing capsule endoscope using external electromagnetic actuation and chemical reaction pressure.

In this paper, we present a tattooing capsule endoscope (TCE) that can localize an intestinal lesion or tumor for a preoperative laparoscopic surgery. The TCE is based on a wireless capsule endoscope (WCE) structure and can be actively controlled by an external electromagnetic actuation system to move, observe, and mark the target lesion in the gastrointestinal (GI) tract. The TCE is designed to perform capsule locomotion, needle extrusion and intrusion motions, and ink injection. First, the TCE is controlled to move to the target lesion during GI tract diagnosis via a capsule endoscopic camera. Further, a tattooing needle is extruded by an electromagnetically controlled mechanism to puncture the tissue. Finally, the tattooing ink is injected by the chemically reacted carbon dioxide gas pressure that is triggered by a shape memory alloy wire and a reed switch. The reed switch is also activated by the external magnetic field flux density. The suggested methods were verified by the ex-vivo experiments. The TCE prototype was able to move to the target lesion and inject the ink beneath the mucosa layer safely, thereby leaving a visible tattooed mark for surgical lesion identification. The proposed TCE method can accelerate the development of functionalities as well as tattooing procedures of the WCE in the GI tract.

Applications of different solvents and conditions for differential extraction of lipopolysaccharide in Gram-negative bacteria.

Lipopolysaccharide (LPS) is one of the major components in the outer membrane of Gram-negative bacteria. However, its heterogeneity and variability in different bacteria and differentiation conditions make it difficult to extract all of the structural variants. We designed a solution to improve quality and biological activity of LPS extracted from various bacteria with different types of LPS, as compared to conventional methods. We introduced a quality index as a simple measure of LPS purity in terms of a degree of polysaccharide content detected by absorbance at 204 nm. Further experiments using gel electrophoresis, endotoxin test, and macrophage activation test were performed to evaluate the performance and reliability of a proposed 'T-sol' method and the biological effectiveness and character of the LPS products. We presented that the T-sol method had differential effects on extraction of a RAW 264.7 cell-activating LPS, which was effective in the macrophage activation with similar effects in stimulating the production of TNF-alpha. In conclusion, the T-sol method provides a simple way to improve quality and biological activity of LPS with high yield.

Nanohybrid magnetic liposome functionalized with hyaluronic acid for enhanced cellular uptake and near-infrared-triggered drug release.

The aim of this work is to prepare and evaluate a novel lipid-polymer hybrid liposomal nanoplatform (hyaluronic acid-magnetic nanoparticle-liposomes, HA-MNP-LPs) as a vehicle for targeted delivery and triggered release of an anticancer drug (docetaxel, DTX) in human breast cancer cells. We first synthesize an amphiphilic hyaluronic acid hexadecylamine polymer (HA-C16) to enhance the targeting ability of the hybrid liposome. Next, HA-MNP-LPs are constructed to achieve an average size of 189.93±2.74nm in diameter. In addition, citric acid-coated magnetic nanoparticles (MNPs) are prepared and embedded in the aqueous cores while DTX is encapsulated in the hydrophobic bilayers of the liposomes. Experiments with coumarin 6 loaded hybrid liposomes (C6/HA-MNP-LPs) show that the hybrid liposomes have superior cellular uptake in comparison with the conventional non-targeting liposomes (C6/MNP-LPs), and the result is further confirmed by Prussian blue staining. Under near-infrared laser irradiation (NIR, 808nm), the HA-MNP-LPs aqueous solution can reach 46.7°C in 10min, and the hybrid liposomes released over 20% more drug than the non-irradiated liposomes. Using a combination of photothermal irradiation and chemotherapy, the DTX-loaded hybrid liposomes (DTX/HA-MNP-LPs) significantly enhance therapeutic efficacy, with the IC50 value of 0.69±0.10µg/mL, which is much lower than the values for DTX monotherapy. Consequently, the prepared hybrid nanoplatform may offer a promising drug delivery vehicle with selective targeting and enhanced drug release in treating CD44-overexpressing cancers.

Shape memory alloy-based biopsy device for active locomotive intestinal capsule endoscope.

Recently, capsule endoscopes have been used for diagnosis in digestive organs. However, because a capsule endoscope does not have a locomotive function, its use has been limited to small tubular digestive organs, such as small intestine and esophagus. To address this problem, researchers have begun studying an active locomotive intestine capsule endoscope as a medical instrument for the whole gastrointestinal tract. We have developed a capsule endoscope with a small permanent magnet that is actuated by an electromagnetic actuation system, allowing active and flexible movement in the patient's gut environment. In addition, researchers have noted the need for a biopsy function in capsule endoscope for the definitive diagnosis of digestive diseases. Therefore, this paper proposes a novel robotic biopsy device for active locomotive intestine capsule endoscope. The proposed biopsy device has a sharp blade connected with a shape memory alloy actuator. The biopsy device measuring 12 mm in diameter and 3 mm in length was integrated into our capsule endoscope prototype, where the device's sharp blade was activated and exposed by the shape memory alloy actuator. Then the electromagnetic actuation system generated a specific motion of the capsule endoscope to extract the tissue sample from the intestines. The final biopsy sample tissue had a volume of about 6 mm(3), which is a sufficient amount for a histological analysis. Consequently, we proposed the working principle of the biopsy device and conducted an in-vitro biopsy test to verify the feasibility of the biopsy device integrated into the capsule endoscope prototype using the electro-magnetic actuation system.