A Cascade Signaling Network between Artificial Cells Switching Activity of Synthetic Transmembrane Channels.

Cell-cell communication plays a vital role in biological activities; in particular, membrane-protein interactions are profoundly significant. In order to explore the underlying mechanism of intercellular signaling pathways, a full range of artificial systems have been explored. However, many of them are complicated and uncontrollable. Herein we designed an artificial signal transduction system able to control the influx of environmental ions by triggering the activation of synthetic transmembrane channels immobilized on giant membrane vesicles (GMVs). A membrane protein-like stimulator from one GMV community (GMVB) stimulates a receptor on another GMV community (GMVA) to release ssDNA messengers, resulting in the activation of synthetic transmembrane channels to enable the influx of ions. This event, in turn, triggers signal responses encapsulated in the GMVA protocell model. By mimicking natural signal transduction pathways, this novel prototype provides a workable tool for investigating cell-cell communication and expands biological signaling systems in general as well as explores useful platforms for addressing scientific problems which involve materials science, chemistry, and medicine.

Conspecific odor cues induce different vocal responses in serrate-legged small treefrogs, but only in the absence of acoustic signals.

BACKGROUND: Signal detection is crucial to survival and successful reproduction, and animals often modify behavioral decisions based on information they obtained from the social context. Undeniably, the decision-making in male-male competition and female choice of anurans (frogs and toads) depends heavily on acoustic signals. However, increasing empirical evidence suggests that additional or alternative types of cue (e.g., visual, chemical, and vibratory) can be used to detect, discriminate and locate conspecifics in many anuran species. Nevertheless, few studies have investigated whether conspecific odor cues affect male's calling behavior. In this study, we conducted an experiment to investigate whether and how different chemical cues (male odors, female odors, and stress odors) from conspecifics affect male's calling strategies in serrate-legged small treefrogs (Kurixalus odontotarsus), and whether the combined chemical and acoustic stimuli have additive effects on calling behavior or not. RESULTS: We found that compared with female odors, male K. odontotarsus reduced calling investment in response to male odors or stress odors, in the absence of rival's advertisement calls. When odor stimuli and advertisement calls were presented simultaneously, however, there were no differences in the vocal response of focal males among odor groups. CONCLUSIONS: These results provide evidence that male treefrogs switch calling investment according to different odor cues from conspecifics, and further demonstrate that calling behavior can be affected by chemical cues in anuran species. Our study highlights the potential role of airborne chemical cues in sex identification and contributes to increase our understanding of anuran communication.

Male serrate-legged treefrogs adjust competition strategies according to visual or chemical cues from females.

There is increasing evidence that many anurans use multimodal cues to detect, discriminate and/or locate conspecifics and thus modify their behaviors. To date, however, most studies have focused on the roles of multimodal cues in female choice or male-male interactions. In the present study, we conducted an experiment to investigate whether male serrate-legged small treefrogs (Kurixalus odontotarsus) used visual or chemical cues to detect females and thus altered their competition strategies in different calling contexts. Three acoustic stimuli (advertisement calls, aggressive calls and compound calls) were broadcast in a randomized order after a spontaneous period to focal males in one of four treatment groups: combined visual and chemical cues of a female, only chemical cues, only visual cues and a control (with no females). We recorded the vocal responses of the focal males during each 3 min period. Our results demonstrate that males reduce the total number of calls in response to the presence of females, regardless of how they perceived the females. In response to advertisement calls and compound calls, males that perceived females through chemical cues produced relatively fewer advertisement calls but more aggressive calls. In addition, they produced relatively more aggressive calls during the playback of aggressive calls. Taken together, our study suggests that male Kodontotarsus adjust their competition strategies according to the visual or chemical cues of potential mates and highlights the important role of multisensory cues in male frogs' perception of females.

Bacterial Cellulose: A Robust Platform for Design of Three Dimensional Carbon-Based Functional Nanomaterials.

Three dimensional (3D) carbon nanomaterials exhibit great application potential in environmental protection, electrochemical energy storage and conversion, catalysis, polymer science, and advanced sensors fields. Current methods for preparing 3D carbon nanomaterials, for example, carbonization of organogels, chemical vapor deposition, and self-assembly of nanocarbon building blocks, inevitably involve some drawbacks, such as expensive and toxic precursors, complex equipment and technological requirements, and low production ability. From the viewpoint of practical application, it is highly desirable to develop a simple, cheap, and environmentally friendly way for fabricating 3D carbon nanomaterials in large scale. On the other hand, in order to extend the application scope and improve the performance of 3D carbon nanomaterials, we should explore efficient strategies to prepare diverse functional nanomaterials based on their 3D carbon structure. Recently, many researchers tend to fabricate high-performance 3D carbon-based nanomaterials from biomass, which is low cost, easy to obtain, and nontoxic to humans. Bacterial cellulose (BC), a typical biomass material, has long been used as the raw material of nata-de-coco (an indigenous dessert food of the Philippines). It consists of a polysaccharide with a ß-1,4-glycosidic linkage and has a interconnected 3D porous network structure. Interestingly, the network is made up of a random assembly of cellulose nanofibers, which have a high aspect ratio with a diameter of 20-100 nm. As a result, BC has a high specific surface area. Additionally, BC hydrogels can be produced on an industrial scale via a microbial fermentation process at a very low price. Thus, it can be an ideal platform for design of 3D carbon-based functional nanomaterials. Before our work, no systematic work and summary on this topic had been reported. This Account presents the concepts and strategies of our studies on BC in the past few years, that is, converting cheap biomass into high value-added 3D carbon nanomaterials and designing diverse functional materials on 3D carbon structure. We first briefly introduce the history, constituent, and microstructure features of BC and discuss its advantages as a raw material for preparing the CNF aerogels. Then, we summarize the methods and strategies for preparing various 3D carbon-based nanomaterials from BC. In addition, the potential applications of the developed CNF aerogel based functional materials are also highlighted in this Account, including stretchable conductors, oxygen reduction reaction catalysts, supercapacitors, lithium-ion battery, and oil cleanup. Finally, we give some prospects on the future challenges in this emerging research area of designing CNF aerogel based functional nanomaterials from BC.

[The efficacy and safety of continuous erythropoietin receptor activator in dialytic patients with chronic renal anemia: an open, randomized, controlled, multi-center trial].

OBJECTIVE: To evaluate the efficacy and safety of continuous erythropoietin receptor activator (C.E.R.A.) once every 4 weeks by subcutaneous administration on hemoglobin (Hb) maintenance in dialytic patients with chronic renal anemia who had been treated with stable dose of erythropoietin (EPO). METHODS: This was an open, randomized, controlled, multi-center trial. All the hemodialysis or peritoneal dialytic patients in EPO maintenance treatment received subcutaneous EPO-ß during the 6-week pre-treatment period to maintain Hb level between 100 g/L and 120 g/L. Eligible patients were randomized (2:1) to accept either C.E.R.A. once every 4 weeks by subcutaneous administration (C.E.R.A. group, n = 187) or subcutaneous EPO-ß 1-3 times weekly (EPO group, n = 94) for 28 weeks (including 20-week dose titration period and 8-week efficacy evaluation period). The starting dose of C.E.R.A. was converted according to the dose of EPO-ß administered in the week preceding the first study drug administration. The primary outcome was the change of Hb level between the baseline and that in the efficacy evaluation period. RESULTS: Totally 253 patients completed the whole 28-week treatment. The change of baseline-adjusted mean Hb was +2.57 g/L for C.E.R.A. group and +1.23 g/L for EPO group, resulting in a treatment difference of 1.34 g/L (95%CI -1.11 - 3.78 g/L). Since the lower limit of 95%CI was greater than the pre-defined non-inferiority margin -7.5 g/L (P < 0.0001), C.E.R.A. once every 4 weeks by subcutaneous administration was clinically non-inferior to EPO regarding the maintenance of stable Hb level. The proportion of patients maintaining Hb level within the range of 100-120 g/L through efficacy evaluation period was similar between the two groups (69.0% for C.E.R.A. group vs 68.9% for EPO group, P > 0.05). The overall incidence of adverse events was similar between the C.E.R.A.(41.7%) and EPO (46.2%) groups (P > 0.05). The safety findings were in accordance with the patients' primary diseases rather than the administration. CONCLUSIONS: Conversion from EPO to C.E.R.A. once every 4 weeks by subcutaneous injection could maintain the Hb in target level in dialytic patients with renal anemia, and it was non-inferior to EPO. In general, subcutaneous administration of C.E.R.A. is well tolerated in dialytic patients with chronic renal anemia.

Endodontic Microsurgery of Mandibular Second Molars Using the Bony Lid Approach: A Case Series.

Endodontic microsurgery is important for preservation of natural teeth with symptomatic apical periodontitis when conventional endodontic treatment is neither feasible nor effective. The thick buccal cortex, poor visibility, and potential neurovascular complications can make microsurgical procedures of mandibular second molars infeasible. With the aid of cone-beam computed tomography, the bony lid approach was applied in 10 cases of endodontic microsurgery of mandibular second molars at the VIP Center, Hangzhou Stomatology Hospital between 2019 and 2020. In all cases, the clinical and radiographic findings at the 24- or 36-month follow-up revealed complete healing of the periapical lesions. The bony lid technique contributed to precise root-end localization and helped avoid excessive postoperative pain or unfavorable healing that occurred in cases of excessive alveolar bone resection. Some clinical tips on preserving the cortical bone, obtaining precise access, and improving surgical efficiency have been proposed in this report.

Incidence and risk factor analysis for swelling after apical microsurgery.

BACKGROUND: Swelling after apical microsurgery is a postoperative reaction and may reduce quality of life during healing. AIM: To evaluate periapical swelling after apical microsurgery and determine potential risk factors. METHODS: Ninety-eight apical microsurgery patients were selected for this study. Before surgery, bone shadow volume and density of pathological tissue were measured by cone beam computed tomography. The other variables (age, gender, operative teeth number, fistula, preoperative swelling, drug use and preoperative root canal treatments) were assessed during examination. Swelling degree was confirmed by questionnaires for patients on postoperative days 1, 7, 14 and 21. Statistical analyses were performed to identify predictors for swelling. RESULTS: Majority of patients reported moderate (45.9%) or severe (34.7%) swelling on day 1, and moderate (44.9%) or mild (45.9%) on postoperative day 7. Ninety-nine percent of patients had no or mild swelling on postoperative day 14. The average swelling level peaked on day 1 postoperatively and gradually decreased. Of statistical significance, age, bone shadow volume and density of pathological tissue acted as predictors of swelling (P < 0.05). However, there was no significant difference in gender, tooth number, fistula, preoperative swelling, drug use, or preoperative root canal treatments (P > 0.05). CONCLUSION: Younger patients with larger shadow volume and density were significantly more likely to develop swelling after apical microsurgery.

In vivo solid-phase microextraction swab-mass spectrometry for multidimensional analysis of human saliva.

Solid phase microextraction (SPME) is one of the most powerful sample preparation techniques for analyte extraction and enrichment from complex matrices. SPME fibers are commonly used to extract analytes from collected samples. Following our recent work on development of in vivo SPME swab that integrates an SPME fiber and a medical swab (Anal Chim Acta, 2020, 1124, 71-77), the multiple SPME fibers inserted into a medical swab (multiple-SPME swab) is further developed to couple with different mass spectrometry (MS) approaches for multidimensional analysis of human saliva in this work. The new features of cotton ball and SPME fiber of multiple-SPME swab are investigated. Biomarker discovery and disease diagnosis using multiple-SPME swab are also demonstrated. The present study shows that direct coupling multiple-SPME swab with different MS-based approaches could be simple and versatile in vivo method to expand the classes of analytes extracted simultaneously from human saliva.

Endodontic Microsurgery with Orthodontic Treatment in a Mandibular Left Molar with Symptomatic Apical Periodontitis.

Endodontic microsurgery has reduced the degree of treatment trauma compared with traditional apical surgery and further increased the success rate of natural teeth retention. However, when root apices of the mandibular posterior teeth are far from the buccal cortical bone surface or near to the inferior alveolar nerve, the operational difficulty of endodontic microsurgery increased greatly. Orthodontic treatments may be helpful to decrease the difficulties. In this case, the roots of a highly calcified mandibular molar diagnosed as previously initiated, symptomatic apical periodontitis were moved initially buccally by orthodontic treatment in 2 months. Then, endodontic microsurgery was completed. The tooth remained asymptomatic and functional with a radiographically healing periapical lesion at the 4-, 12-, and 24-month follow-ups.

DNA-based artificial molecular signaling system that mimics basic elements of reception and response.

In order to maintain tissue homeostasis, cells communicate with the outside environment by receiving molecular signals, transmitting them, and responding accordingly with signaling pathways. Thus, one key challenge in engineering molecular signaling systems involves the design and construction of different modules into a rationally integrated system that mimics the cascade of molecular events. Herein, we rationally design a DNA-based artificial molecular signaling system that uses the confined microenvironment of a giant vesicle, derived from a living cell. This system consists of two main components. First, we build an adenosine triphosphate (ATP)-driven DNA nanogatekeeper. Second, we encapsulate a signaling network in the biomimetic vesicle, consisting of distinct modules, able to sequentially initiate a series of downstream reactions playing the roles of reception, transduction and response. Operationally, in the presence of ATP, nanogatekeeper switches from the closed to open state. The open state then triggers the sequential activation of confined downstream signaling modules.

Mate choice decisions of female serrate-legged small treefrogs are affected by ambient light under natural, but not enhanced artificial nocturnal light conditions.

Artificial light at night (ALAN) is a widespread anthropogenic stimulus that can significantly alter nocturnal animals' behavior, from migration to foraging to vocal communication. In the present study, we tested the hypothesis that the mate choice decisions of female serrate-legged small treefrogs (Kurixalus odontotarsus) were influenced by ambient light intensity. Standard two-speaker phonotaxis tests were conducted in a sound attenuating chamber. We set four light treatments (I-IV, from low to high) based on a range of light intensities from the maximum natural light at night (i.e., full moon) to that of the actual calling sites, which had artificial light. Contrary to our prediction, female frogs showed a preference for calls on the bright side in treatment I when they were exposed to identical stimuli. However, females preferred longer calls on the dim side to shorter calls on the bright side in this treatment. In addition, there were no significant effects of choice side, light treatment or their interaction on leave time or choice time. Our results suggest that females are more attracted to mates in bright light under natural nocturnal light conditions, but the preference for longer calls is not altered in serrate-legged small treefrogs.

High-throughput polymer tip-electrospray ionization mass spectrometry for enhanced detection of neopterin and biopterin in clinical urine samples.

Urinary biopterin (Bio) and neopterin (Neo) are important markers for clinical diagnosis of hyperphenylalaninemia. Herein, we developed a high-throughput analysis method based on electrospray ionization mass spectrometry (ESI-MS) with polymer tips for the rapid quantitative detection of Bio and Neo in clinical urine samples. Different polymer tips were investigated. It is found that the best detection sensitivity was achieved with hydrophobic polymer tip, ie, polyethylene tips. The high-throughput polymer tip-ESI-MS method allowed a rapid analysis speed at ~40 seconds per sample. The limits of quantification (LOQ) (S/N ≥ 10) for the detection of Bio and Neo were improved to be 5.0 ng/mL. Acceptable relative standard deviation (RSD) values for Neo and Bio were measured to be 12.2% and 13.4% for direct measurement of Bio and Neo in raw urine samples, respectively. Furthermore, Bio and Neo were directly quantified from 18 clinical urine samples by presented method. The ratios of urinary Bio-to-Neo were analyzed for diagnosis of hyperphenylalaninemia. The results demonstrated that the present polymer tip-ESI-MS method is a promising strategy for the rapid analysis of clinical samples.

Structural design approaches for creating fat droplet and starch granule mimetics.

This article focuses on hydrogel-based strategies for creating reduced calorie foods with desirable physicochemical, sensory, and nutritional properties. Initially, the role of fat droplets and starch granules in foods is discussed, and then different methods for fabricating hydrogel beads are reviewed, including phase separation, antisolvent precipitation, injection, and emulsion template methods. Finally, the potential application of hydrogel beads as fat droplet and starch granule replacements is discussed. There is still a need for large-scale, high-throughout, and economical methods of fabricating hydrogel beads suitable for utilization within the food industry.

Chemosensitization and radiosensitization of a lung cancer cell line A549 induced by a composite polymer micelle.

Multidrug resistance (MDR) to Doxorubicin (DOX) remains a major obstacle to successful cancer treatment. The present study sought to overcome the MDR of lung cancer cells and achieve radiosensitization by developing a composite DOX-loaded micelle (M-DOX). M-DOX containing PEG-PCL/Pluronic P105 was prepared by the solvent evaporation method. Lung cancer cell line A549 was adopted in this study. In vitro cytotoxicity, cellular uptake behavior, subcellular distribution, and radiosensitivity were evaluated by the treatment with M-DOX, and free DOX was used as a control. A549 cells treated with M-DOX as opposed to free DOX showed greater cellular uptake as well as greater cytotoxicity. Furthermore, M-DOX reached the mitochondria and lysosome effectively after cellular uptake, and fluorescence used to track M-DOX was found to be surrounding the nucleus. Finally, colony-forming assays demonstrated that M-DOX treatment improved radiosensitization when compared to free DOX. Based on the increased cytotoxicity and radiosensitization, M-DOX could be considered as a promising drug delivery system to overcome MDR in lung cancer therapy.

Development of hydrocolloid microgels as starch granule mimetics: Hydrogel particles fabricated from gelatin and pectin.

In this study, hydrocolloid microgels fabricated by electrostatic complexation of gelatin and pectin were developed as possible starch mimetics. The impact of covalent cross-linking on the physicochemical and structural properties of the microgels was investigated. Microgels were formed by acidifying a mixture of gelatin (0.5wt.%) and pectin (0.01wt.%) from pH10 to 5 at 40°C, followed by cross-linking with glutaraldehyde (0 to 2mM). At low glutaraldehyde levels (<0.5mM), cross-linking occurred primarily within the microgels and did not affect particle dimensions, whereas at high levels (2mM), cross-linking connected adjacent microgels leading to the formation of large flocs. Rheological and microscopic analysis showed that the degree of cross-linking impacted the thermal transitions of the microgels. A simulated oral processing study indicated that the melt-in-the-mouth behavior of the hydrocolloid microgels could be made to be similar to that of starch granules by controlling the degree of cross-linking. This study may be useful for designing starch mimetics with improved texture-modifying properties and reduced-calories.

Soft matter strategies for controlling food texture: formation of hydrogel particles by biopolymer complex coacervation.

Soft matter physics principles can be used to address important problems in the food industry. Starch granules are widely used in foods to create desirable textural attributes, but high levels of digestible starch may pose a risk of diabetes. Consequently, there is a need to find healthier replacements for starch granules. The objective of this research was to create hydrogel particles from protein and dietary fiber with similar dimensions and functional attributes as starch granules. Hydrogel particles were formed by mixing gelatin (0.5 wt%) with pectin (0 to 0.2 wt%) at pH values above the isoelectric point of the gelatin (pH 9, 30 °C). When the pH was adjusted to pH 5, the biopolymer mixture spontaneously formed micron-sized particles due to electrostatic attraction of cationic gelatin with anionic pectin through complex coacervation. Differential interference contrast (DIC) microscopy showed that the hydrogel particles were translucent and spheroid, and that their dimensions were determined by pectin concentration. At 0.01 wt% pectin, hydrogel particles with similar dimensions to swollen starch granules (D3,2 ≈ 23 µm) were formed. The resulting hydrogel suspensions had similar appearances to starch pastes and could be made to have similar textural attributes (yield stress and shear viscosity) by adjusting the effective hydrogel particle concentration. These hydrogel particles may therefore be used to improve the texture of reduced-calorie foods and thereby help tackle obesity and diabetes.

Structure of the human Tim44 C-terminal domain in complex with pentaethylene glycol: ligand-bound form.

Familial oncocytic thyroid carcinoma is associated with a missense mutation, P308Q, in the C-terminal domain of Tim44. Tim44 is the mitochondrial inner-membrane translocase subunit and it functions as a membrane anchor for the mitochondrial heat-shock protein 70 (mtHsp70). Here, the crystal structure of the human Tim44 C-terminal domain complexed with pentaethylene glycol has been determined at 1.9 A resolution. The overall structure resembles that of the nuclear transport factor 2-like domain. In the crystal structure, pentaethylene glycol molecules are associated at two potential membrane-binding sites: the large hydrophobic cavity and the highly conserved loop between the alpha1 and alpha2 helices near Pro308. A comparison with the yeast homolog revealed that lipid binding induces conformational changes around the alpha1-alpha2 loop, leading to slippage of the alpha1 helix along the large beta-sheet. These changes may play important roles in the translocation of polypeptides across the mitochondrial inner membrane.

Structural basis for the exocellulase activity of the cellobiohydrolase CbhA from Clostridium thermocellum.

Numerous bacterial and fungal organisms have evolved elaborate sets of modular glycoside hydrolases and similar enzymes aimed at the degradation of polymeric carbohydrates. Presently, on the basis of sequence similarity catalytic modules of these enzymes have been classified into 90 families. Representatives of a particular family display similar fold and catalytic mechanisms. However, within families distinctions occur with regard to enzymatic properties and type of activity against carbohydrate chains. Cellobiohydrolase CbhA from Clostridium thermocellum is a large seven-modular enzyme with a catalytic module belonging to family 9. In contrast to other representatives of that family possessing only endo- and, in few cases, endo/exo-cellulase activities, CbhA is exclusively an exocellulase. The crystal structures of the combination of the immunoglobulin-like module and the catalytic module of CbhA (Ig-GH9_CbhA) and that of an inactive mutant Ig-GH9_CbhA(E795Q) in complex with cellotetraose (CTT) are reported here. The detailed analysis of these structures reveals that, while key catalytic residues and overall fold are conserved in this enzyme and those of other family 9 glycoside hydrolases, the active site of GH9_CbhA is blocked off after the -2 subsite. This feature which is created by an extension and altered conformation of a single loop region explains the inability of the active site of CbhA to accommodate a long cellulose chain and to cut it internally. This altered loop region is responsible for the exocellulolytic activity of the enzyme.

Poly(L-lysine)-modified silica nanoparticles for the delivery of antisense oligonucleotides.

Silica nanoparticles were prepared in a microemulsion system, using polyoxyethylene nonylphenyl ether/cyclohexane/ammonium hydroxide. The surface charge of the particle was modified with PLL [poly(L-lysine)]. PAGE demonstrated the ability of PMS-NP (PLL-modified silica nanoparticles) to bind and protect antisense ODNs (oligonucleotides). The intracellular localization of FITC-labelled ODN was investigated by fluorescence microscopy. The results demonstrated that ODN could be delivered to cytoplasm. Flow-cytometry analysis showed a 20-fold enhancement of ODN delivered by PMS-NP compared with free ODN for a serum-free medium. Blocking efficacy of c- myc antisense ODN, delivered by PMS-NP, was examined in HNE1 and HeLa cell lines. Significant down-regulation of c- myc mRNA levels was observed in both the cell lines. However, the cellular uptake efficiency and antisense effects on target gene decreased in the presence of serum-containing medium. The analysis of the filtration assay showed that PMS-NP interacted with serum proteins. These results indicated that PMS-NP was a suitable delivery vector for antisense ODN, although its delivery efficiency decreased in the presence of a serum-containing medium.