Rapid and sensitive detection of gram-negative bacteria using surface-immobilized polymyxin B.

Although detection of gram-negative bacteria (GNB) in body fluids is important for clinical purpose, traditional gram staining and other recently developed methods have inherent limitations in terms of accuracy, sensitivity, and convenience. To overcome the weakness, this study proposed a method detecting GNB based on specific binding of polymyxin B (PMB) to lipopolysaccharides (LPS) of GNB. Fluorescent microscopy demonstrated that surface immobilized PMB using a silane coupling agent was possible to detect fluorescent signal produced by a single Escherichia coli (a model GNB) cell. Furthermore, the signal was selective enough to differentiate between GNB and gram-positive bacteria. The proposed method could detect three cells per ml within one hour, indicating the method was very sensitive and the sensing was rapid. These results suggest that highly multifold PMB binding on each GNB cell occurred, as millions of LPS are present on cell wall of a GNB cell. Importantly, the principle used in this study was realized in a microfluidic chip for a sample containing E. coli cells suspended in porcine plasma, demonstrating its potential application to practical uses. In conclusion, the proposed method was accurate, sensitive, and convenient for detecting GNB, and could be applied clinically.

Chronic frontal neurobehavioural symptoms in combat-deployed military personnel with and without a history of blast-related mild traumatic brain injury.

OBJECTIVE: This study evaluated frontal behavioural symptoms, via the FrSBe self-report, in military personnel with and without a history of blast-related mild traumatic brain injury (mild TBI). METHODS: Prospective observational cohort study of combat-deployed service members leveraging 1-year and 5-year demographic and follow up clinical outcome data. RESULTS: The blast mild TBI group (n = 164) showed greater frontal behavioural symptoms, including clinically elevated apathy, disinhibition, and executive dysfunction, during a 5-year follow-up, compared to a group of combat-deployed controls (n = 107) without mild TBI history or history of blast exposure. We also explored changes inbehaviourall symptoms over a 4-year span, which showed clinically significant increases in disinhibition in the blast mild TBI group, whereas the control group did not show significant increases in symptoms over time. CONCLUSION: Our findings add to the growing evidence that a proportion of individuals who sustain mild TBI experience persistent behavioural symptoms. We also offer a demonstration of a novel use of the FrSBe as a tool for longitudinal symptom monitoring in a military mild TBI population.

Stretchable and Skin-Mountable Temperature Sensor Array Using Reduction-Controlled Graphene Oxide for Dermatological Thermography.

Since thermometry of human skin is critical information that provides important aspects of human health and physiology, accurate and continuous temperature measurement is required for the observation of physical abnormalities. However, conventional thermometers are uncomfortable because of their bulky and heavy features. In this work, we fabricated a thin, stretchable array-type temperature sensor using graphene-based materials. Furthermore, we controlled the degree of graphene oxide reduction and enhanced the temperature sensitivity. The sensor exhibited an excellent sensitivity of 2.085% °C-1. The overall device was designed in a wavy meander shape to provide stretchability for the device so that precise detection of skin temperature could be performed. Furthermore, polyimide film was coated to secure the chemical and mechanical stabilities of the device. The array-type sensor enabled spatial heat mapping with high resolution. Finally, we introduced some practical applications of skin temperature sensing, suggesting the possibility of skin thermography and healthcare monitoring.

Specificity of performance validity tests in patients with confirmed epilepsy.

Objective: While assessment of performance validity is essential to neuropsychological evaluations, use of performance validity tests (PVTs) in an epilepsy population has raised concerns due to factors that may result in performance fluctuations. The current study assessed whether specificity was maintained at previously suggested cutoffs in a confirmed epilepsy population on the Warrington Recognition Memory Test (WRMT) - Words and Test of Memory Malingering (TOMM). Method: Eighty-two confirmed epilepsy patients were administered the WRMT-Words and TOMM as part of a standardized neuropsychological evaluation. Frequency tables were utilized to investigate specificity rates on these two PVTs. Results: The suggested WRMT-Words Accuracy Score cutoff of ≤42 was associated with a specificity rate of 90.2%. Five out of the 8 individuals falling below the Accuracy Score cutoff scored 42, suggesting specificity could be further improved by slightly lowering the cutoff. The WRMT-Words Total Time cutoff of ≥207 seconds was associated with 95.1% specificity. A TOMM Trial 1 cutoff of <40 was associated with 93.9% specificity, while the established cutoff of <45 on Trial 2 and the Retention Trial yielded specificity rates of 98.6% and 100.0%, respectively. Conclusions: Our findings demonstrate acceptable performance on two PVTs in a select confirmed epilepsy population without a history of brain surgery, active seizures during testing, and/or low IQ, irrespective of various factors such as seizure type, seizure lateralization/localization, and language lateralization. The possible presence of interictal discharges were not controlled for in the current study, which may have contributed to reduced PVT performances.

Different contribution of exoelectrogens in methanogenesis via direct interspecies electron transfer (DIET) by the different substrate in continuous anaerobic bioreactor.

Direct interspecies electron transfer (DIET) is a syntrophic mechanism for electron transfer between exo- and endoelectrogens. Previous studies have demonstrated that methanogenesis performance was significantly improved via the DIET mechanism through conductive materials (CMs) under batch conditions with a single substrate, while that under continuous condition is still under investigation. To investigate how the DIET via CM on methanogenesis performance was changed in response to the different substrates (acetate versus glucose)-fed in continuous anaerobic bioreactors, continuous bioreactors were operated by cross-feeding with acetate and glucose. Acetate-fed conditions showed 0.40 day shorten lagtime, 1.88- and 1.22-folds higher methane production rate, and ultimate methane production than glucose-fed conditions, respectively. Burkholderiaceae- and Anaerolineaceae-related exo-electrogenic populations were enriched with low abundance of Geobacter species in batch reactors. Furthermore, influent substrates affected the distribution of the enriched populations. Taken together, the results suggested that different syntrophic associations contributed methane production by DIET in continuous bioreactors.

A Case of Linear Exacerbation of Atopic Dermatitis with Secondary Prurigo Nodularis.

Inflammatory acquired Blaschko-linear dermatoses (IABLD) are a continuous concept involving diseases such as lichen striatus, blaschkitis, and atopic dermatitis. However, atopic dermatitis that showed increase in severity along Blaschko lines is rarely reported on its own. Herein, we report a rare case of atopic dermatitis with secondary prurigo nodularis along Blaschko lines, which may be valuable in broadening the concept of IABLD. A 28-year-old male presented with multiple, pruritic, brownish nodules on the left lower extremity along Blaschko lines for 3 to 4 years. The patient had atopic dermatitis since childhood. Histopathologic findings revealed compact orthohyperkeratosis, hypergranulosis, spongiosis, and irregular acanthosis in the epidermis. Fibrosis with vertically arranged collagen fibers and perivascular lymphohistiocytic infiltration were shown in the upper dermis. We diagnosed the case as secondary prurigo nodularis along Blaschko lines, accompanied by the preceding atopic dermatitis. We hypothesized that the patient's underlying atopic dermatitis increased in severity along Blaschko lines, and prurigo nodularis occurred due to frequent scratching. The lesions improved with topical methylprednisolone cream, oral antihistamines and intralesional triamcinolone injection.

Recurrent Cellulitis Associated with Acupuncture with Migratory Gold Threads.

In Asian countries, acupuncture with gold threads has been widely used in the treatment of pain. However, several reports have suggested that the implanted gold threads can become fragmented and migrate to other parts of the body, damaging surrounding tissues. A 75-year-old female presented with diffuse erythematous edema with multiple vesicles on the right lower leg for 3 days. She had previously suffered from cellulitis on the same region twice for the last 1 year. Her past medical history included acupuncture with gold threads on the back due to lumbar herniated nucleus pulposus (HNP) about 10 years ago. Histopathological examination demonstrated marked subepithelial edema and diffuse perivascular infiltrate of inflammatory cells in the dermis. Simple radiography of the leg revealed numerous radiodense threads in the soft tissue. Since the patient did not receive acupuncture on any other sites except on the back, we hypothesized that the gold threads injected on the back may have migrated through the vessels to the leg. These metal fragments can cause inflammatory reaction and make the tissues more susceptible to secondary infections. The lesion gradually improved after treatment with systemic steroid and antibiotics for 1 week.

Effect of microbial community structure in inoculum on the stimulation of direct interspecies electron transfer for methanogenesis.

To investigate how the seed microbial community structure affects the improvement of methanogenesis efficiency through direct interspecies electron transfer (DIET), a biomethane potential (BMP) test was conducted using sludge collected from a total of six anaerobic digesters. DIET-stimulating microbial populations were investigated by 16S rRNA gene sequence analysis. Correlations between microbial community composition and methane production performance by DIET were analyzed. The methane production rate increased under all conditions when granular activated carbon (GAC) was injected regardless of the inoculum type. However, redundancy analysis indicated a significant correlation between the inoculum microbial community and lag time. In a network analysis, Methanolinea species distributed in the inocula formed a single modularity with lag time, suggesting that the methanogens in the inocula might reduce the lag time of methanogenesis through DIET. Overall, this study revealed that the inoculum microbial community composition is an important factor affecting methane production efficiency by DIET.

A study on the performance of the Donation Improvement Program in Korea.

Background: The Donation Improvement Program (DIP) is intended to increase organ donation at hospitals. The program includes education for healthcare professionals of participating hospitals about each step of donation as well as evaluation. The DIP consists of medical record review (MRR) and a Hospital Attitude Survey (HAS). The purpose of this study was to evaluate the DIP results for the last 7 years. Methods: For MRR, we analyzed 58,385 cases of mortality from 77 hospitals between 2012 and 2018. The HAS data for the degree of education experience, competence, and knowledge related to brain death (BD) and donation were analyzed from 23 DIP-participating hospitals in 2012 and 51 DIP-participating hospitals in 2015 and 2018 each. Results: The recognition rate of potential BD was 24.9%, 61.3%, and 73.2%, and donation rate was 7.5%, 11.7%, and 15.8% at 6 months before, 1?2 years after, and 4?5 years after the agreement, respectively. Hospital staff with the necessary competence or knowledge to explain BD constituted 44.0% in 2012, while this increased to 62.8% in 2018. Conclusions: The DIP could increase the recognition of BD and the organ donation rate, and positively affect the attitudes of healthcare professionals toward organ donation. Spreading the DIP to all hospitals is urgent to increase organ donation.

Effect of broad-spectrum biofilm inhibitor raffinose, a plant galactoside, on the inhibition of co-culture biofilm on the microfiltration membrane.

A membrane bioreactor (MBR) integrates process such as membrane filtration and biological treatment of activated sludge. However, organic, inorganic and biological matters cause membrane fouling, which seriously affects membrane performance. The goal of this study was to evaluate the biofouling inhibition capacity of raffinose during the MBR process. The results showed that 0-1,000 µM raffinose significantly reduced the formation of the P. aeruginosa and S. aureus co-culture biofilm by about 25-52 % in a concentration-dependent manner. In addition, the effect of raffinose on the microfiltration membrane biofilm was tested in a flow reactor and lab-scale MBR unit. The results showed that the co-culture biofilm and transmembrane pressure were decreased by raffinose treatment compared to those by furanone C-30 treatment. These results clearly demonstrated that raffinose, broad-spectrum biofilm inhibitor, inhibits biofilm formation in mixed cultures and could be used to mitigate biofouling in MBR processes.

Recent advances in methanogenesis through direct interspecies electron transfer via conductive materials: A molecular microbiological perspective.

Conductive materials can serve as biocatalysts during direct interspecies electron transfer for methanogenesis in anaerobic reactors. However, the mechanism promoting direct interspecies electron transfer in anaerobic reactors, particularly under environments in which diverse substrates and microorganisms coexist, remains to be elucidated from a scientific or an engineering point of view. Currently, many molecular microbiological approaches are employed to understand the fundamentals of this phenomenon. Here, the direct interspecies electron transfer mechanisms and relevant microorganisms identified to date using molecular microbiological methods were critically reviewed. Moreover, molecular microbiological methods for direct interspecies electron transfer used in previous studies and important findings thus revealed were analyzed. This review will help us better understand the phenomena of direct interspecies electron transfer using conductive materials and offer a framework for future molecular microbiological studies.

Effect of inoculum concentration on methanogenesis by direct interspecies electron transfer: Performance and microbial community composition.

To understand the effect of inoculum concentration on direct interspecies electron transfer (DIET) for methanogenesis, batch-type anaerobic bioreactors with different inoculum concentrations were operated with and without supplemented granular activated carbon (GAC). With decrease in inoculum concentration, GAC-supplemented bioreactors showed faster methane production rates and reduced lag times. Geobacter species were specifically enriched on the GAC surfaces under lower inoculum concentration conditions. Together, the relative abundance of aceticlastic methanogens (competitors of Geobacter species for acetate) gradually decreased when the inoculum concentration increased. These results suggested that the specific enrichment of Geobacter species by outcompeting with aceticlastic methanogens through low inoculum concentrations on GAC surfaces accelerated methanogenesis by DIET via GAC in anaerobic bioreactors. Taken together, the results of this study suggested that inoculum concentration is an important factor in stimulating DIET for methane production.

Small-Molecule-Targeting Hairpin Loop of hTERT Promoter G-Quadruplex Induces Cancer Cell Death.

Increased telomerase activity is associated with malignancy and poor prognosis in human cancer, but the development of targeted agents has not yet provided clinical benefit. Here we report that, instead of targeting the telomerase enzyme directly, small molecules that bind to the G-hairpin of the hTERT G-quadruplex-forming sequence kill selectively malignant cells without altering the function of normal cells. RG260 targets the hTERT G-quadruplex stem-loop folding but not tetrad DNAs, leading to downregulation of hTERT expression. To improve physicochemical and pharmacokinetic properties, we derived a small-molecule analog, RG1603, from the parent compound. RG1603 induces mitochondrial defects including PGC1α and NRF2 inhibition and increases oxidative stress, followed by DNA damage and apoptosis. RG1603 injected as a single agent has tolerable toxicity while achieving strong anticancer efficacy in a tumor xenograft mouse model. These results demonstrate a unique approach to inhibiting the hTERT that functions by impairing mitochondrial activity, inducing cell death.

Antibacterial application of covalently immobilized photosensitizers on a surface.

Singlet oxygen produced by irradiating photosensitizers (PSs) can be used to kill pathogens during water treatment. Chemical immobilization of the PSs on surfaces can maintain their disinfection function long-term. In this study, two model PSs (rose bengal (RB) and hematoporphyrin (HP)) were immobilized on a glass surface using a silane coupling agent with an epoxide group, and their antibacterial properties were analyzed. Fourier transform infrared spectroscopy demonstrated that a covalent bond formed between the epoxide group and hydroxyl group in the PSs. A large proportion of the immobilized PSs (approximately 50%) was active in singlet oxygen production, which was evidenced by a comparative analysis with free PSs. RB was more effective at producing singlet oxygen than HP. The immobilized PSs were durable in terms of repeated use. On the other hand, singlet oxygen produced by the PSs was effective at killing bacteria, mostly for Gram-positive bacteria (> 90% death for 2 h of irradiation), by damaging the cell membrane. The preferable antibacterial property against Gram-positive bacteria compared with that against Gram-negative bacteria suggested efficient penetrability of singlet oxygen across the cell membrane, which led to cell death. Taken together, it was concluded that immobilization of PSs on surfaces using the silane coupling agent proposed in this study was effective at killing Gram-positive bacteria by forming singlet oxygen.

Direct interspecies electron transfer via conductive materials: A perspective for anaerobic digestion applications.

Anaerobic digestion (AD) is a microbial process that produces renewable energy in the form of methane by treating organic waste and high-strength wastewater. Recent studies have demonstrated that conductive materials can promote direct interspecies electron transfer (DIET) between exoelectrogenic bacteria and methanogenic archaea. DIET via conductive materials is more effective for methane production than interspecies electron transfer using electron carriers such as hydrogen, a principal route of methane production in conventional AD. This critical review presents the current understanding of DIET via conductive materials for methane production, summarizes the relevant studies published to date, and analyzes these studies with regard to conductive materials, substrates, inocula, performance, and microorganisms. Based on this analysis, possible future directions are suggested for practical DIET applications via conductive materials in AD.

A Pharmacological Chaperone Molecule Induces Cancer Cell Death by Restoring Tertiary DNA Structures in Mutant hTERT Promoters.

Activation of human telomerase reverse transcriptase (hTERT) is necessary for limitless replication in tumorigenesis. Whereas hTERT is transcriptionally silenced in normal cells, most tumor cells reactivate hTERT expression by alleviating transcriptional repression through diverse genetic and epigenetic mechanisms. Transcription-activating hTERT promoter mutations have been found to occur at high frequencies in multiple cancer types. These mutations have been shown to form new transcription factor binding sites that drive hTERT expression, but this model cannot fully account for differences in wild-type (WT) and mutant promoter activation and has not yet enabled a selective therapeutic strategy. Here, we demonstrate a novel mechanism by which promoter mutations activate hTERT transcription, which also sheds light on a unique therapeutic opportunity. Promoter mutations occur in a core promoter region that forms tertiary structures consisting of a pair of G-quadruplexes involved in transcriptional silencing. We show that promoter mutations exert a detrimental effect on the folding of one of these G-quadruplexes, resulting in a nonfunctional silencer element that alleviates transcriptional repression. We have also identified a small drug-like pharmacological chaperone (pharmacoperone) molecule, GTC365, that acts at an early step in the G-quadruplex folding pathway to redirect mutant promoter G-quadruplex misfolding, partially reinstate the correct folding pathway, and reduce hTERT activity through transcriptional repression. This transcription-mediated repression produces cancer cell death through multiple routes including both induction of apoptosis through inhibition of hTERT's role in regulating apoptosis-related proteins and induction of senescence by decreasing telomerase activity and telomere length. We demonstrate the selective therapeutic potential of this strategy in melanoma cells that overexpress hTERT.

Interaction of Individual Structural Domains of hnRNP LL with the BCL2 Promoter i-Motif DNA.

The recently discovered role of the BCL2 (B-cell lymphoma 2 gene) promoter i-motif DNA in modulation of gene expression via interaction with the ribonucleoprotein hnRNP L-like (hnRNP LL) has prompted a more detailed study of the nature of this protein-DNA interaction. The RNA recognition motifs (RRMs) of hnRNP LL were expressed individually, and both RRM1 and RRM2 were found to bind efficiently to the BCL2 i-motif DNA, as well as being critical for transcriptional activation, whereas RRM3-4 bound only weakly to this DNA. Binding was followed by unfolding of the DNA as monitored by changes in the CD spectrum. Mutational analysis of the i-motif DNA revealed that binding involved primarily the lateral loops of the i-motif. The kinetics of binding of the DNA with RRM1 was explored by recording CD spectra at predetermined times following admixture of the protein and DNA. The change in molar ellipticity was readily apparent after 30 s and largely complete within 1 min. A more detailed view of protein-DNA interaction was obtained by introducing the fluorescence donor 6-CNTrp in RRM1 at position 137, and the acceptor 4-aminobenzo[g]quinazoline-2-one (Cf) in lieu of cytidine22 in the i-motif DNA. The course of binding of the two species was monitored by FRET, which reflected a steady increase in energy transfer over a period of several minutes. The FRET signal could be diminished by the further addition of (unlabeled) RRM2, no doubt reflecting competition for binding to the i-motif DNA. These experiments using the individual RRM domains from hnRNP LL confirm the role of this transcription factor in activation of BCL2 transcription via the i-motif in the promoter element.

Influence of influent wastewater communities on temporal variation of activated sludge communities.

Continuously feeding influent wastewater containing diverse bacterial species to a wastewater treatment activated sludge bioreactor may influence the activated sludge bacterial community temporal dynamics. To explore this possibility, this study tracked influent wastewater and activated sludge bacterial communities by pyrosequencing 16S rRNA genes from four full-scale wastewater treatment plants over a 9-month period. The activated sludge communities showed significantly higher richness and evenness than the influent wastewater communities. Furthermore, the two communities were different in composition and temporal dynamics. These results demonstrate that the impact of the influent wastewater communities on the activated sludge communities was weak. Nevertheless, 4.3-9.3% of the operational taxonomic units (OTUs) detected in the activated sludge were shared with the influent wastewater, implying contribution from influent wastewater communities to some extent. However, the relative OTU abundance of the influent wastewater was not maintained in the activated sludge communities (i.e., weak neutral assembly). In addition, the variability of the communities of the shared OTUs was moderately correlated with abiotic factors imposed to the bioreactors. Taken together, temporal dynamics of activated sludge communities appear to be predominantly explained by species sorting processes in response to influent wastewater communities.