Formation of functional nanobiocatalysts with a novel and encouraging immobilization approach and their versatile bioanalytical applications

The discovery of functional organic–inorganic hybrid nanoflowers (FNFs) consisting of proteins/enzymes as the organic components and Cu(ii) ion as the inorganic component has made an enormous impact on enzyme immobilization studies. The FNFs synthesized by an encouraging and novel approach not only showed high stabilities but also much enhanced catalytic activities as compared to free and conventionally immobilized enzymes. A recent development demonstrated that FNF formation has moved beyond the initial discovery in which enzymes and Cu²⁺ ions used as the organic and inorganic parts, respectively, are replaced with new organic (chitosan, amino acid and plant extracts) and inorganic (Cu²⁺ and Fe²⁺) materials. The new organic materials incorporated into FNFs act as Fenton-like agents and then show peroxidase-like activity owing to the metal ions and the porous structure of FNFs in the presence of hydrogen peroxide (H₂O₂). All FNFs have been widely utilized in many different scientific and industrial fields due to their greatly enhanced activities and stabilities. This review focuses primarily on the preparation, characterization, and bioanalytical applications of FNFs and explains the mechanisms of their formation and enhanced activities and stabilities.

The discovery of functional organic–inorganic hybrid nanoflowers (FNFs) consisting of proteins/enzymes as the organic components and Cu(ii) ion as the inorganic component has made an enormous impact on enzyme immobilization studies.     

Internalized Stigma in Pediatric Psoriasis: A Comparative Multicenter Study

BackgroundInternalized stigma, adoption of negative attitudes and stereotypes of the society regarding persons'' illness, has not been studied previously in pediatric psoriasis patients.ObjectiveWe aimed to investigate the internalized stigma in pediatric psoriasis patients and to determine differences according to factors affecting internalized stigma compared to adult psoriasis patients.MethodsThis multicenter, cross-sectional, comparative study included 125 pediatric (55 female, 70 male; mean age±standard deviation [SD], 14.59±2.87 years) and 1,235 adult psoriasis patients (577 female, 658 male; mean age±SD, 43.3±13.7 years). Psoriasis Internalized Stigma Scale (PISS), Dermatology Life Quality Index (DLQI), Perceived Health Status (PHS), and the General Health Questionnaire (GHQ)-12 were the scales used in the study.ResultsThe mean PISS was 58.48±14.9 in pediatric group. When PISS subscales of groups were compared, the pediatric group had significantly higher stigma resistance (p=0.01) whereas adult group had higher scores of alienation (p=0.01) and stereotype endorsement (p=0.04). There was a strong correlation between mean values of PISS and DLQI (r=0.423, p=0.001). High internalized stigma scores had no relation to either the severity or localization of disease in pediatric group. However, poor PHS (p=0.007) and low-income levels (p=0.03) in both groups, and body mass index (r=0.181, p=0.04) in the pediatric group were related to high PISS scores.ConclusionInternalized stigma in pediatric patients is as high as adults and is related to poor quality of life, general health, and psychological illnesses. Unlike adults, internalized stigma was mainly determined by psoriasis per se, rather than disease severity or involvement of visible body parts, genitalia or folds.     

DLQI scores in patients with keloids and hypertrophic scars: a prospective case control study

Background: Keloids and hypertrophic scars (HTS) can cause functional impairment and psychosocial burdens, both of which affects quality of life (QoL). Our aim was to compare Dermatology Life Quality Index (DLQI) scores in patients with keloids and HTS to those of psoriasis patients and normal controls. Patients and Methods: Forty‐eight consecutive patients with keloids and HTS and 48 with psoriasis vulgaris attending our dermatology outpatient clinic, as well as 48 sex‐ and age‐matched healthy controls completed the DLQI. Results: Total DLQI scores of patients with keloids and HTS (7.79 ± 5.10) and psoriasis (8.73 ± 5.63) were comparable and significantly higher than that of healthy controls (0.58 ± 0.77). No significant difference were found between patients with psoriasis and patients with keloids and HTS in terms of the total DLQI scores and the subscale scores (p > 0.05) except “treatment” (p < 0.05) sub‐scale scores which were higher in psoriasis. Conclusions: The QoL of patients with keloids and HTS is impaired as much as that of those with psoriasis. The DLQI questionnaire is a reliable and valid instrument for assessing the QoL in patients with keloids and HTS.     

Comparison of iodine-125 plaque brachytherapy and gamma knife stereotactic radiosurgery treatment outcomes for uveal melanoma patients

Graefe's Archive for Clinical and Experimental Ophthalmology - To compare the efficacies of iodine-125 brachytherapy (IBT) and gamma knife stereotactic radiosurgery (GKRS) in the treatment of...     

Optical Coherence Tomographic Findings in Susac Syndrome

Purpose: To report optical coherence tomographic (OCT) findings in Susac syndrome. Methods: A 15-year-old girl who had symptoms of deafness and encephalopathy was referred with a provisional diagnosis of Susac syndrome. Funduscopy revealed cotton wool spots and ischaemic cloudy swelling of the retina. Results: OCT taken from the abnormal retinal area showed increased reflectivity of the inner retinal layers and decreased reflectivity from the outer retinal layers and the retinal pigment epithelium due to shadowing. Neither intraretinal nor subretinal fluid were observed on the OCT imaging. OCT findings were compatible with the accepted view that the retinal pathology in Susac syndrome is due to arteriolar occlusion. Conclusion: OCT may be used as a complementary diagnostic method to fluorescein angiography in Susac syndrome.     

Linking function to global and local dynamics in an elevator-type transporter

Transporters cycle through large structural changes to translocate molecules across biological membranes. The temporal relationships between these changes and function, and the molecular properties setting their rates, determine transport efficiency—yet remain mostly unknown. Using single-molecule fluorescence microscopy, we compare the timing of conformational transitions and substrate uptake in the elevator-type transporter Glt_Ph. We show that the elevator-like movements of the substrate-loaded transport domain across membranes and substrate release are kinetically heterogeneous, with rates varying by orders of magnitude between individual molecules. Mutations increasing the frequency of elevator transitions and reducing substrate affinity diminish transport rate heterogeneities and boost transport efficiency. Hydrogen deuterium exchange coupled to mass spectrometry reveals destabilization of secondary structure around the substrate-binding site, suggesting that increased local dynamics leads to faster rates of global conformational changes and confers gain-of-function properties that set transport rates.

Transporters are integral membrane proteins that move solutes across lipid bilayers. They undergo concerted conformational changes, allowing alternate exposure of their substrate-binding sites to external and internal solutions (1). In each of these so-called outward- and inward-facing states (OFS and IFS, respectively), further isomerizations accompany substrate binding and release. Transport efficiency depends on the rates of these rearrangements, but linking function and structural dynamics has presented methodological challenges. Single-molecule Forster resonance energy transfer (smFRET)-based total internal reflection fluorescence (TIRF) microscopy (2–4) has been used to monitor the dynamics of the OFS to IFS transitions (5–8) and single-transporter activity (9) in the elevator-type transporter Glt_Ph and other transporters (10–18). Hydrogen–deuterium exchange followed by mass spectrometry (HDX-MS) has been used to pinpoint local changes in structural dynamics in diverse biological systems (19–21). Here, we combine these approaches to link changes in local protein dynamics to the larger-scale conformational transitions and substrate transport in wild-type (WT) and gain-of-function mutants of Glt_Ph.Glt_Ph is an extensively studied archaeal aspartate transporter that is homologous to human excitatory amino acid transporters (EAATs). Structures of Glt_Ph (7, 22–30), and archaeal and mammalian homologs (31–37), show that the transporters assemble into homotrimers via scaffold domains. Each protomer features a mobile transport domain that binds l-Aspartate (l-Asp) and three Na⁺ ions (22, 23, 28, 31, 38) and symports the solutes by an elevator mechanism, moving ∼15 Å across the membrane from an OFS to an IFS (6, 8, 23, 24, 39). During the elevator transitions, two structurally symmetric helical hairpins (HPs) 1 and 2 form the cores of the domain interfaces in the OFS and IFS, respectively (SI Appendix, Fig. S1A) (23, 24, 40). Despite symmetry, they do not have the same function. HP1 is mostly rigid, while HP2 is a conformationally plastic “master regulator” of the transporter, gating substrate in the OFS and IFS and contributing to setting the elevator transition rates (5, 23, 24, 27, 29, 36, 41–47).In this study, we use three previously characterized mutants of Glt_Ph to pinpoint the rate-limiting steps of the transport cycle and probe the protein dynamic properties that correlate with increased transport rates. A K290A mutation at the base of HP1 disrupts a salt bridge with the scaffold domain in the OFS and dramatically increases the elevator dynamics (5, 6). A triple-mutant Y204L/A345V/V366A displays a more modest increase in elevator dynamics and substantially diminished l-Asp affinity (5). Finally, a Y204L/K290A/A345V/V366A mutant combines these substitutions and their effects (5). We compared our previously obtained smFRET data on the elevator dynamics of the WT transporter and the mutants (5) to single-transporter uptake measurements. For WT Glt_Ph, these dynamics and transport measurements established transporter subpopulations that move (5, 6) and work (9) with rates differing by orders of magnitude, with slow transporters dominating the ensemble. We now show that only mutations that both reduce the population of the slow-moving transporters and weaken substrate affinity, such as Y204L/A345V/V366A, reduce the population of the slow-working transporters and confer overall gain-of-function properties. The slow-working population comprises transporters with rare elevator transitions or slow substrate release. We then used HDX-MS to explore how the Y204L/A345V/V366A mutant differed from the WT protein. We found that the mutations decreased the stability of the secondary structure around the substrate-binding site, suggesting that the increased local dynamics underlie reduced kinetic heterogeneity within the mutant transporter ensemble.     

Regenerating heavily biofouled dissolved oxygen sensors using bacterial viruses

Bacterial biofilms are aggregates of bacterial cells embedded in a self-produced extracellular polymeric matrix. Biofilm formation has always been considered a major challenge for sensors used in underwater measurements, and is a primary source of measurement error, especially when it comes to long-term in situ monitoring. We demonstrate the utility of lytic bacteriophages (bacterial viruses) as a non-invasive strategy for removing bacterial biofilms formed on the gas permeable membrane of electrochemical dissolved oxygen sensors. Our results show that a 4 day Pseudomonas aeruginosa biofilm with a fully developed matrix significantly affected the sensor signal and response time, decreasing the signal by 32% and increasing the response time by 94%. In addition, measurements with the biofouled membrane had a very low signal to nose ratio compared to a clean sensor membrane. A single dose of overnight phage treatment effectively removed the biofilm (as indicated by scanning electron micrographs and fluorescence images of the membrane), without the need for repeated treatments. Furthermore, the sensor signal that had plummeted by 32% for a fully biofouled membrane, was returned to the original value (7.96 ± 0.27 mg L⁻¹) after phage treatment and the signal to noise ratio (calculated as the ratio of mean to standard deviation) increased 8 folds for a phage-treated membrane compared to a biofouled membrane. Our data indicate near complete regeneration and signal recovery for the dissolved oxygen sensor, making the biofouled sensor reusable without the use of harsh chemicals that could destroy the fragile sensor membrane.

Lytic bacteriophages can be utilized as a non-invasive method for removing bacterial biofilms formed on the surface of gas permeable membranes of dissolved oxygen sensors.     

哈萨克医常用的几种植物药及其应用

本文对5种哈萨克医常用药材的基原,形态特征,生境分布,采集加工,化学成分,性味功能,主治,用量等几方面做一介绍,并提出了深入研究哈萨克药,使之更好的服务于人类的健康事业等建议。