Antimicrobial Resistance Profiles, Virulence Genes, and Genetic Diversity of Thermophilic Campylobacter Species Isolated From a Layer Poultry Farm in Korea

Thermophilic Campylobacter species are among the major etiologies of bacterial enteritis globally. This study aimed at assessing the antimicrobial resistance (AMR) profiles, virulence genes, and genetic diversity of thermophilic Campylobacter species isolated from a layer poultry farm in South Korea. One hundred fifty-three chicken feces were collected from two layer poultry farms in Gangneung, South Korea. The Campylobacter species were isolated by cultural techniques, while PCR and sequencing were used for species confirmation. Antimicrobial susceptibility testing for six antimicrobials [ciprofloxacin (CIP), nalidixic acid (NAL), sitafloxacin (SIT), erythromycin (ERY), tetracycline (TET), and gentamicin (GEN)] was carried out by broth microdilution. Three AMR and nine virulence genes were screened by PCR. Genotyping was performed by flaA-restriction fragment length polymorphism (RFLP) and multilocus sequence typing (MLST). Of the 153 samples, Campylobacter spp. were detected in 55 (35.9%), with Campylobacter jejuni and Campylobacter coli being 49 (89.1%) and six (10.9%), respectively. High-level resistance was observed for CIP (100%), NAL (100%), and TET (C. jejuni, 93.9%; C. coli: 83.3%). No resistance was observed for SIT. The missense mutation (C257T) in gyrA gene was confirmed by sequencing, while the tet(O) gene was similar to known sequences in GenBank. The rate of multidrug-resistant (MDR) strains was 8.2%, and they all belonged to C. jejuni. All Campylobacter isolates possessed five virulence genes (cdtB, cstII, flaA, cadF, and dnaJ), but none possessed ggt, while the rates for other genes (csrA, ciaB, and pldA) ranged between 33.3 and 95.9%. The flaA-RFLP yielded 26 flaA types (C. jejuni: 21 and C. coli: five), while the MLST showed 10 sequence types (STs) for C. jejuni and three STs for C. coli, with CC-607 (STs 3611) and CC-460 (ST-460) being predominant. Among the 10 STs of C. jejuni, three were newly assigned. The findings of this study highlight the increased resistance to quinolones and TET, the virulence potential, and the diverse genotypes among Campylobacter strains isolated from the layer poultry farm.

Susceptibility of Campylobacter Strains to Selected Natural Products and Frontline Antibiotics

Campylobacter species have developed resistance to existing antibiotics. The development of alternative therapies is, therefore, a necessity. This study evaluates the susceptibility of Campylobacter strains to selected natural products (NPs) and frontline antibiotics. Two C. jejuni strains (ATCC^® 33560^TM and MT947450) and two C. coli strains (ATCC^® 33559^TM and MT947451) were used. The antimicrobial potential of the NPs, including plant extracts, essential oils, and pure phytochemicals, was evaluated by broth microdilution. The growth was measured by spectrophotometry and iodonitrotetrazolium chloride. Antibiotic resistance genes (tet(O) and gyrA) were characterized at the molecular level. The minimum inhibitory concentrations (MICs) and the minimum bactericidal concentrations (MBCs) ranged from 25 to 1600 µg/mL. Cinnamon oil, (E)-Cinnamaldehyde, clove oil, eugenol, and baicalein had the lowest MIC and MBC values (25-100 µg/mL). MT947450 and MT947451 were sensitive to erythromycin and gentamicin but resistant to quinolones and tetracycline. Mutations in gyrA and tet(O) genes from resistant strains were confirmed by sequencing. The findings show that NPs are effective against drug-sensitive and drug-resistant Campylobacter strains. The resistance to antibiotics was confirmed at phenotypic and genotypic levels. This merits further studies to decipher the action mechanisms and synergistic activities of NPs.

Oleuropein suppresses LPS-induced inflammatory responses in RAW 264.7 cell and zebrafish

Oleuropein is one of the primary phenolic compounds present in olive leaf. In this study, the anti-inflammatory effect of oleuropein was investigated using lipopolysaccharide (LPS)-stimulated RAW 264.7 and a zebrafish model. The inhibitory effect of oleuropein on LPS-induced NO production in macrophages was supported by the suppression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2). In addition, our enzyme immunoassay showed that oleuropein suppressed the release of pro-inflammatory cytokines such as interleukin-1β (IL-1β) and interleukin-6 (IL-6). Oleuropein inhibited the translocation of p65 by suppressing phosphorylation of inhibitory kappa B-α (IκB-α). Oleuropein also decreased activation of ERK1/2 and JNK, which are associated with LPS-induced inflammation, and its downstream gene of AP-1. Furthermore, oleuropein inhibited LPS-stimulated NO generation in a zebrafish model. Taken together, our results demonstrated that oleuropein could reduce inflammatory responses by inhibiting TLR and MAPK signaling, and may be used as an anti-inflammatory agent.

Growth of textured thin Au coatings on iron oxide nanoparticles with near infrared absorbance

A homologous series of Au coated iron oxide nanoparticles with hydrodynamic diameters smaller than 60 nm was synthesized with very low Au-to-iron mass ratios, as low as 0.15. The hydrodynamic diameter was determined by dynamic light scattering and the composition by atomic absorption spectroscopy and energy dispersive x-ray spectroscopy. Unusually low Au precursor supersaturation levels were utilized to nucleate and grow Au coatings on iron oxide relative to the formation of pure Au nanoparticles. This approach produced unusually thin coatings by lowering autocatalytic growth of Au on Au, as shown by transmission electron microscopy. Nearly all of the nanoparticles were attracted by a magnet, indicating a minimal number of pure Au particles. The coatings were sufficiently thin to shift the surface plasmon resonance to the near infrared with large extinction coefficients, despite the small particle hydrodynamic diameters observed from dynamic light scattering to be less than 60 nm.

Low molecular weight fucoidan from the sporophyll of Undaria pinnatifida suppresses inflammation by promoting the inhibition of mitogen-activated protein kinases and oxidative stress in RAW264.7 cells

The suppression of MAPK and oxidative stress could be an important anti-inflammatory mechanism. Fucoidan regulates MAPK activity in several cell lines. However, the mechanism for the anti-inflammatory and oxidative stress effect of low molecular weight fucoidan (LMWF) is poorly understood in RAW264.7 cells. The objective of this study was to examine the critical role of LMWF during LPS-induced inflammation in RAW264.7 cells. To determine the potential role of LMWF, we analysed pro-inflammatory cytokine, transcription factor, inflammation-related and oxidative stress related protein expression in vitro during LPS-induced inflammation in RAW264.7 cells. In this study, we demonstrated the anti-inflammatory effects of LMWF on LPS-induced inflammation in macrophages through the regulation of signalling pathways, including its effect on the attenuation of inflammatory cytokines, such as IL-1β, IL-1 and TNF-α, and the degradation of phosphorylated p38 MAPK, ERK1/2 and JNK. This study also demonstrates that LMWF might block NO as well as the expression of reactive oxygen species (ROS), which subsequently inhibits the iNOS and COX-2 expression induced by LPS. Based on these findings, we suggest that LMWF might have great potential as an external pathogen prevention and intervention agent for inflammatory diseases.

Fucoidan regulate blood glucose homeostasis in C57BL/KSJ m+/+db and C57BL/KSJ db/db mice

Type 2 diabetes mellitus is a multisystem disease that is characterized by hyperglycemia and is associated with the dysfunction and failure of various organs. The control of postprandial hyperglycemia is important in the prevention and intervention of type 2 diabetes. Fucoidan has several biological activities in vitro and in vivo. However, the effect of fucoidan on hyperglycemia in non-diabetic and diabetic mice has not been investigated. This study was undertaken to study the effects of different molecular weight forms (5 kilodalton (k), 5-30 k and crude) of fucoidan on oral glucose tolerance tests in non-diabetic mice and on food intake, weight gain, fasting blood glucose and blood biochemistry of db/db mice. Treatment with 200 mg/mL 5 k, 5-30 k and crude fucoidan substantially prevented hyperglycemia according to oral glucose tolerance tests in non-diabetic mice. In addition, fucoidan fractions significantly reduced blood glucose levels in diabetic mice.

SEAWEED EXTRACTS AS A POTENTIAL TOOL FOR THE ATTENUATION OF OXIDATIVE DAMAGE IN OBESITY-RELATED PATHOLOGIES1

Recent studies suggest that seaweed extracts are a significant source of bioactive compounds comparable to the dietary phytochemicals such as onion and tea extracts. The exploration of natural antioxidants that attenuate oxidative damage is important for developing strategies to treat obesity-related pathologies. The objective of this study was to screen the effects of seaweed extracts of 49 species on adipocyte differentiation and reactive oxygen species (ROS) production during the adipogenesis in 3T3-L1 adipocytes, and to investigate their total phenol contents and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activities. Our results show that high total phenol contents were observed in the extracts of Ecklonia cava (see Table 1 for taxonomic authors) (681.1 ± 16.0 μg gallic acid equivalents [GAE] · g^-1 ), Dictyopteris undulata (641.3 ± 70.7 μg GAE · g^-1 ), and Laurencia intermedia (560.9 ± 48.1 μg GAE · g^-1 ). In addition, DPPH radical scavenging activities were markedly higher in Sargassum macrocarpum (60.2%), Polysiphonia morrowii (55.0%), and Ishige okamurae (52.9%) than those of other seaweed extracts (P < 0.05). Moreover, treatment with several seaweed extracts including D. undulata, Sargassum micracanthum, Chondrus ocellatus, Gelidium amansii, Gracilaria verrucosa, and Grateloupia lanceolata significantly inhibited adipocyte differentiation and ROS production during differentiation of 3T3-L1 preadipocytes. Furthermore, the production of ROS was positively correlated with lipid accumulation (R²  = 0.8149). According to these preliminary results, some of the seaweed extracts can inhibit ROS generation, which may protect against oxidative stress that is linked to obesity. Further studies are required to determine the molecular mechanism between the verified seaweeds and ROS, and the resulting effects on obesity. [Table: see text].

Enhanced pulsed magneto-motive ultrasound imaging using superparamagnetic nanoclusters

Recently, pulsed magneto-motive ultrasound (pMMUS) imaging augmented with ultra-small magnetic nanoparticles has been introduced as a tool capable of imaging events at molecular and cellular levels. The sensitivity of a pMMUS system depends on several parameters, including the size, geometry and magnetic properties of the nanoparticles. Under the same magnetic field, larger magnetic nanostructures experience a stronger magnetic force and produce larger displacement, thus improving the sensitivity and signal-to-noise ratio (SNR) of pMMUS imaging. Unfortunately, large magnetic iron-oxide nanoparticles are typically ferromagnetic and thus are very difficult to stabilize against colloidal aggregation. In the current study we demonstrate improvement of pMMUS image quality by using large size superparamagnetic nanoclusters characterized by strong magnetization per particle. Water-soluble magnetic nanoclusters of two sizes (15 and 55 nm average size) were synthesized from 3 nm iron precursors in the presence of citrate capping ligand. The size distribution of synthesized nanoclusters and individual nanoparticles was characterized using dynamic light scattering (DLS) analysis and transmission electron microscopy (TEM). Tissue mimicking phantoms containing single nanoparticles and two sizes of nanoclusters were imaged using a custom-built pMMUS imaging system. While the magnetic properties of citrate-coated nanoclusters are identical to those of superparamagnetic nanoparticles, the magneto-motive signal detected from nanoclusters is larger, i.e. the same magnetic field produced larger magnetically induced displacement. Therefore, our study demonstrates that clusters of superparamagnetic nanoparticles result in pMMUS images with higher contrast and SNR.

Lab-scale test of a ventilation system including a dielectric barrier discharger and UV-photocatalyst filters for simultaneous removal of gaseous and particulate contaminants

A ventilation system including a dielectric barrier discharger (DBD) and UV-photocatalyst (UVP) filters was designed and tested for simultaneous removal of gaseous and particulate contaminants in a test chamber. The DBD was used in the first stage of electrostatic precipitator (ESP) for particle charging and gas decomposition. An applied DC electric field was used in the second stage of ESP to collect the charged particles. UVP filters were then used to decompose gaseous species, such as formaldehyde (HCHO) and benzene, toluene, and xylene (BTX) including O3, which was inherently produced by the DBD. %Reductions in mass concentration of PM2.5 and number concentration of submicron particles were approximately 79.5% and 76.3%, respectively, after the ventilation with air cleaning system was operated for 5 h. Both HCHO and BTX were completely removed when the initial concentration of each gas was 1 ppm.

PRACTICAL IMPLICATIONS

Indoor air quality (IAQ) problems, such as sick building syndrome (SBS), are caused by limited ventilation in high-rise buildings. To overcome these problems, DBD and UVP filters were applied into a lab-scale ventilation system for simultaneous removal of pollutant particles and gases. The data supplied in this study will be useful for designing any actual ventilation system after further research, including scale-up experiments.

Dopamine transporter density measured by [123I]beta-CIT single-photon emission computed tomography is normal in dopa-responsive dystonia

The clinical distinction between dopa-responsive dystonia (DRD) and juvenile Parkinson's disease JPD) can pose a diagnostic challenge. Both conditions are dopa responsive. However, long-term L-dopa benefit is very different between the two. The difference in the prognosis is due to presence or absence of nigral cell loss. In JPD, there is degenerative nigral cell loss, whereas there are enzymatic defects in dopamine synthesis without cell loss in DRD. Mutations have been found in the GTP cyclohydrolase I (GCH-I) and tyrosine hydroxylase genes in DRD. As the discovered mutations are multiple and more are expected to be found, it is difficult to confirm or exclude DRD by mutation studies. Measurement of cerebrospinal fluid (CSF) neopterin will detect DRD from mutations in the GCH-I gene but not from mutations in tyrosine hydroxylase. The dopamine transporter (DAT) is a protein in the dopaminergic nerve terminals. (1R)-2beta-Carbomethoxy-3beta-(4-[123I]iodophenyl)tropane ([123I]beta-CIT) is a ligand for the DAT, and it was shown to be a useful nuclear imaging marker for neurons that degenerate in Parkinson's disease (PD). As DRD was shown to have a normal DAT without nigral cell loss in a postmortem study, we predicted that the DAT measured in vivo by nuclear imaging will be normal in DRD and will differentiate DRD from JPD. Therefore, we performed [123I]beta-CIT single-photon emission computed tomography ([123I]beta-CIT SPECT) in clinically diagnosed DRD, PD, and JPD, and examined whether DAT imaging can differentiate DRD from PD and JPD. We then examined whether DAT imaging can provide a screening tool for molecular genetic studies, by studying mutations in the candidate gene GCH-I and measuring CSF neopterin. Five females (4 from two families, and 1 sporadic) were diagnosed as DRD based on early-onset foot dystonia and progressive parkinsonism beginning at ages 7 to 12. All patients were functioning normally on L-dopa 100 to 250 mg/day for up to 8 years. SPECT imaging was obtained after intravenous injection of [123I]beta-CIT; 15 healthy volunteers served as normal control, and 6 PD and 1 JPD as disease controls. [123I]beta-CIT striatal binding was normal in DRD, whereas it was markedly decreased in PD and JPD. Gene analysis showed a novel nonsense mutation in the GCH-I gene in one family. No mutation was found in the other family or in the sporadic case. CSF neopterin was markedly decreased in the 4 tested patients. [123I]beta-CIT SPECT is a sensitive method for probing the integrity of nigrostriatal dopaminergic nerve terminals. A normal striatal DAT in a parkinsonian patient is evidence for a nondegenerative cause of parkinsonism and differentiates DRD from JPD. Finding a new mutation in one family and failure to demonstrate mutations in the putative gene in other cases supports the usefulness of DAT imaging in diagnosing DRD.