Provide Attachment Sites Research Articles

Photocurrent polarity switching photoelectrochemical aptasensor for oxytetracycline based on BiOBr/Ag2S/PDA//CuO: CuO-induced II-type to dual Z-scheme system

BackgroundAs a broad-spectrum tetracycline antibiotic, Oxytetracycline (OTC) was widely used in a variety of applications. But, the overuse of OTC had led to the detection of it in food, water and soil, which could present significance risk to human health and cause damage to ecosystem. It was of great significance to develop sensitive detection methods for OTC.Herein, an environmentally friendly photoelectrochemical (PEC) aptasensor was constructed for the sensitive detection of OTC based on CuO-induced BiOBr/Ag2S/PDA (Polydopamine) photocurrent polarity reversal. ResultsBiOBr/Ag2S/PDA composites modified electrode not only produced stable initial anodic photocurrent but also provided attachment sites for the aptamer S1 of OTC by the strong adhesion of PDA. On the other hand, CuO loaded OTC aptamer S2 (Cu–S2) was got through Cu–S bonds. After the target OTC was identified on the electrode surface, CuO was introduced to the surface of ITO/BiOBr/Ag2S/PDA through the specific binding of OTC to S2. This identification process formed dual Z-type heterojunctions and resulted in a remarkable reversal of photocurrent polarity from anodic to cathodic. Under optimization conditions, the PEC aptasensor showed a wide linear range (50 fM ∼ 100 nM), low detection limit (1.9 fM), excellent selectivity, stability and reproducibility for the detection of OTC. Moreover, it was successfully used for the analysis of OTC in real samples of tap water, milk and honey, and had the potential for practical application. SignificanceThis work developed an environmentally friendly photocurrent-polarity-switching PEC aptasensor with excellent selectivity, reproducibility, stability, low LOD and wide linear range for OTC detection. This sensitive system, which was including BiOBr, Ag2S, PDA and CuO were low toxicity, not only reduced the risk of traditional toxic semiconductors to operators and the environment, but can also be used for the detection of real samples, broadening the wider range of applications for BiOBr, Ag2S, PDA and CuO.

The mechanism of microbial sulfate reduction in high concentration sulfate wastewater enhanced by maifanite

Excessive sulfate levels in water bodies pose a dual threat to the ecological environment and human health. The microbial removal of sulfate encounters challenges, particularly in environments with high sulfate concentrations, where the gradual accumulation of sulfide hampers microbial activity. This study focuses on elucidating the mechanisms underlying the enhancement of microbial sulfate reduction in high-concentration sulfate wastewater through a comparative analysis of maifanite and zeolite biostimulants. The investigation reveals that zeolite primarily facilitates microbial growth by providing attachment sites, while maifanite augments sulfate-reducing bacteria (SRB) activity through the release of active substances such as Mo, Ca, and Cu. The addition of maifanite proves instrumental in enhancing microbial activity, manifesting as increased microbial load and protein production, augmented extracellular polymer generation, accelerated electron transfer, and facilitated microbial growth and biofilm formation. Noteworthy is the observation that the combined application of maifanite and zeolite exhibited a synergistic effect, resulting in a 167 % and 68 % increase in sulfate reduction rate compared to the utilization of maifanite (0.12 d−1) or zeolite (0.19 d−1) in isolation. Within this synergistic context, the relative abundance of Desulfobacteraceae reaches a peak of 15.4 %. The outcomes of this study corroborate the distinct promotion mechanisms of maifanite and zeolite in microbial sulfate reduction, offering novel insights into the application of maifanite in the context of high-concentration sulfate removal.

Airway epithelial CD47 plays a critical role in inducing influenza virus-mediated bacterial super-infection.

Respiratory viral infection increases host susceptibility to secondary bacterial infections, yet the precise dynamics within airway epithelia remain elusive. Here, we elucidate the pivotal role of CD47 in the airway epithelium during bacterial super-infection. We demonstrated that upon influenza virus infection, CD47 expression was upregulated and localized on the apical surface of ciliated cells within primary human nasal or bronchial epithelial cells. This induced CD47 exposure provided attachment sites for Staphylococcus aureus, thereby compromising the epithelial barrier integrity. Through bacterial adhesion assays and in vitro pull-down assays, we identified fibronectin-binding proteins (FnBP) of S. aureus as a key component that binds to CD47. Furthermore, we found that ciliated cell-specific CD47 deficiency or neutralizing antibody-mediated CD47 inactivation enhanced in vivo survival rates. These findings suggest that interfering with the interaction between airway epithelial CD47 and pathogenic bacterial FnBP holds promise for alleviating the adverse effects of super-infection.

Research on the Dyeing Properties of Chinese Fir Using Ultrasonic-Assisted Mulberry Pigment Dyeing

Wood dyeing plays a crucial role in improving the aesthetic appeal of wood. To enhance the value of Chinese fir, this study used environmentally friendly mulberry pigment and ultrasonic technology to dye Chinese fir. A single-factor test was conducted to investigate the impact of ultrasonic power, dyeing temperature, dyeing time, and dye concentration on dye uptake and color difference. The results revealed that ultrasonic treatment significantly increased the dye uptake and color difference compared with conventional water bath dyeing methods. Based on the single-factor test, two indexes for the color fastness of washing and sun were added, and an orthogonal test was carried out. The range analysis results demonstrated that ultrasonic power had the greatest influence on dye uptake, while dye concentration showed the strongest impact on the color difference and color fastness in washing and sunlight. The dyeing process was optimized using the fuzzy comprehensive evaluation method, with the optimum parameters determined as follows: ultrasonic power of 340 W, dyeing temperature of 90 °C, dyeing time of 5 h, and dye concentration of 10%. Scanning electron microscopy revealed that ultrasound increased wood permeability and created cracks, providing attachment sites for dye molecules. Infrared analysis indicated that ultrasonic action enhanced the degradation of wood components, transforming them into smaller molecular substances and increasing the accessibility of dyes to wood. X-ray diffraction analysis demonstrated that ultrasonic action reduced wood crystallinity, facilitating the entry of dye molecules into Chinese fir fibers. In this study, we proposed for the first time to dye fir wood with mulberry pigment and use ultrasonic-assisted dyeing to investigate the effect of dyeing factors on the dyeing rate, color difference, and color fastness, which provides a valuable reference for natural pigment dyeing of Chinese fir.

Research and analysis of the properties of bredigite-based 3D-printed bone scaffolds.

The use of bone tissue-engineered scaffolds for repairing bone defects has become extremely common. Bone tissue-engineered scaffolds should have good mechanical properties, a pore structure similar to that of natural bone, appropriate biodegradability, and good biocompatibility to provide attachment sites for growth factors and seed cells. They also need to exhibit special functions such as osteoconductivity and osteoinduction. In this study, the mechanical, degradation, and biological properties of bredigite were studied by using a triply periodic minimal surface (TPMS) model structure. Pressure tests on bone tissue-engineered scaffolds showed that the mechanical properties of TPMS scaffolds were significantly better than those of open-rod scaffolds with the same porosity. By analyzing the biological properties, we found that the TPMS model had better protein adsorption ability than the open-rod model, the cells could better adsorb on the surface of the TPMS scaffold, and the proliferation number and proliferation rate of the TPMS model were higher than those of the open-ended rod model.

Removal of Antibiotic Resistance Genes from Animal Wastewater by Ecological Treatment Technology Based on Plant Absorption.

With the aim of controlling the pollution of antibiotic resistance genes (ARGs) in livestock and poultry wastewater, this paper highlights an ecological treatment technology based on plant absorption and comprehensively discusses the removal effect, driving factors, removal mechanism, and distribution characteristics of ARGs in plant tissues. The review shows that ecological treatment technology based on plant absorption has gradually become an important method of wastewater treatment of livestock and poultry breeding and has a good ARG removal effect. In plant treatment ecosystems, microbial community structure is the main driver of ARGs, while mobile genetic elements, other pollutants, and environmental factors also affect the growth and decline of ARGs. The role of plant uptake and adsorption of matrix particles, which provide attachment sites for microorganisms and contaminants, cannot be ignored. The distribution characteristics of ARGs in different plant tissues were clarified and their transfer mechanism was determined. In conclusion, the main driving factors affecting ARGs in the ecological treatment technology of plant absorption should be grasped, and the removal mechanism of ARGs by root adsorption, rhizosphere microorganisms, and root exudates should be deeply explored, which will be the focus of future research.

Pt-Doped Biomass Carbon Decorated with MoS2 Nanosheets as an Electrocatalyst for Hydrogen Evolution

It is necessary to develop an efficient hydrogen evolution catalyst to improve the efficiency of the hydrogen evolution reaction (HER). Herein, a MoS2 nanosheet is decorated on the Pt-doping biomass yeast cells (MoS2@Pt/YC) via a simple hydrothermal process. Reducing the noble metal loading without compromising its performance is a challenging task. The smooth surface of YCs is conducive to the growth of MoS2 nanosheets, and its functional groups provide attachment sites for metal Pt. The Pt/YC is covered with MoS2 nanosheets, thus improving the exposed active sites for HER. The obtained MoS2@Pt/YC delivers a competitive overpotential of 118 mV at the benchmark current density of 10 mA cm-2 and achieves a small Tafel slope of 74 mV dec-1, indicating the great HER performance of MoS2@Pt/YC. Moreover, MoS2@Pt/YC shows robust stability after 24 h of continuous operation toward HER in acidic solution. By introducing transition metal sulfides with high specific surface area, the loading of precious metals can be reduced without compromising properties. This work provides a method to design Pt-doping HER electrocatalysts through a simple method. The facile preparation process for MoS2@Pt/YC and its outstanding performance allow it to be a promising electrocatalyst for practical HER application.

Streptococcus mutans membrane vesicles inhibit the biofilm formation of Streptococcus gordonii and Streptococcus sanguinis

Streptococcus mutans, whose main virulence factor is glucosyltransferase (Gtf), has a substantial impact on the development of dental caries. S. mutans membrane vesicles (MVs), which are rich in Gtfs, have been shown to affect biofilm formation of other microorganisms. Streptococcus gordonii and Streptococcus sanguinis are initial colonizers of tooth surfaces, which provide attachment sites for subsequent microorganisms and are crucial in the development of oral biofilms. S. mutans and S. gordonii, as well as S. mutans and S. sanguinis, have a complex competitive and cooperative relationship, but it is unclear whether S. mutans MVs play a role in these interspecific interactions. Therefore, we co-cultured S. mutans MVs, having or lacking Gtfs, with S. gordonii and S. sanguinis. Our results showed that S. mutans MVs inhibited biofilm formation of S. gordonii and S. sanguinis but did not affect their planktonic growth; contrastingly, S. mutans ΔgtfBC mutant MVs had little effect on both their growth and biofilm formation. Additionally, there were fewer and more dispersed bacteria in the biofilms of the S. mutans MV-treated group than that in the control group. Furthermore, the expression levels of the biofilm-related virulence factors GtfG, GtfP, and SpxB in S. gordonii and S. sanguinis were significantly downregulated in response to S. mutans MVs. In conclusion, the results of our study showed that S. mutans MVs inhibited biofilm formation of S. gordonii and S. sanguinis, revealing an important role for MVs in interspecific interactions.

Doxycycline combined manure microbes to enhances biofilm formation of the soil plastisphere and increases the surface bio-risk of microplastics vehicle

Microbial biofilms can protect bacteria against environmental stresses, such as antibiotics. Microplastics (MPs) provide attachment sites for microbes to form biofilms in aquatic systems; however, in terrestrial systems, research is still lacking, especially in croplands under fertilization and antibiotic exposure. The present study revealed the effects of different doxycycline (DOX) concentrations on the soil plastisphere by examining biofilm formation regularity and the risk posed by MP-attached strains during manuring. The results showed that soil MP biofilm formation could be enhanced by DOX exposure, especially in low-DOX-concentration group over 60 days, and the biofilm formation gene (BFG) expression level on MPs was stronger in low-DOX-exposure group. DOX exposure increased the abundance of most tet genes on the MPs, and the intl1 abundance was highly increased in the DOX exposure groups (enhanced to 1.07 × 108–8.37 × 107 copies/g). DOX exposure increased the diversity of bacteria that were both potential antibiotic resistance gene (ARG) hosts and biofilm-producing strains on MPs, and low DOX exposure enhanced the abundance of potential pathogens on MPs. The correlations among biofilms, ARGs and DOX on soil MPs were promoted by DOX exposure. Further experiments also proved that both MPs and DOX existing enhanced the biofilm production ability of the strains, and the biofilm production ability of the strains attached to the MPs was stronger than that of planktonic cells. This study revealed that DOX exposure, typically low concentrations of DOX, could increase ARG transfer and the abundance of residual pathogens on MPs through biofilm production and the associated protection during manuring.

Utilization of Lead Slag as In Situ Iron Source for Arsenic Removal by Forming Iron Arsenate.

In situ treatment of acidic arsenic-containing wastewater from the non-ferrous metal smelting industry has been a great challenge for cleaner production in smelters. Scorodite and iron arsenate have been proved to be good arsenic-fixing minerals; thus, we used lead slag as an iron source to remove arsenic from wastewater by forming iron arsenate and scorodite. As the main contaminant in wastewater, As(III) was oxidized to As(V) by H2O2, which was further mineralized to low-crystalline iron arsenate by Fe(III) and Fe(II) released by lead slag (in situ generated). The calcium ions released from the dissolved lead slag combined with sulfate to form well-crystallized gypsum, which co-precipitated with iron arsenate and provided attachment sites for iron arsenate. In addition, a silicate colloid was generated from dissolved silicate minerals wrapped around the As-bearing precipitate particles, which reduced the arsenic-leaching toxicity. A 99.95% removal efficiency of arsenic with initial concentration of 6500 mg/L was reached when the solid-liquid ratio was 1:10 and after 12 h of reaction at room temperature. Moreover, the leaching toxicity of As-bearing precipitate was 3.36 mg/L (As) and 2.93 mg/L (Pb), lower than the leaching threshold (5 mg/L). This work can promote the joint treatment of slag and wastewater in smelters, which is conducive to the long-term development of resource utilization and clean production.

Effect of the substrate surface and nutrient adsorption and elution on the growth of benthic diatom Nitzschia palea

Benthic diatoms are beneficial organisms whose activity supports ecosystems and improves water quality. The pennate diatom Nitzschia palea is an important diatom species, as it has a potential to control cyanobacterial blooms. Several studies have attempted to restore lakes by using artificially produced substrates that remove nutrients or harmful substances. Although substrates provide attachment sites, they may adversely affect the growth of diatoms by removing nutrients. In this study, we investigated a suitable substrate for N. palea growth. Substrates such as glass beads, activated carbon, and oyster shells, which can be used for lake water or ecosystem restoration, were selected. The most suitable substrate was determined from the perspective of nutrient adsorption, elution, and availability of adhesion sites. N. palea was cultivated with substrates until the stationary growth phase was attained, and N. palea growth and the change in nutrient content of the medium were investigated. Silicate eluted from small glass beads considerably increased the maximum cell yield of N. palea (7.03 × 106 cells mL−1). Activated carbon absorbed nitrate from the medium and decreased the specific growth rate of N. palea from 0.47 d−1 (without substrate) to 0.24 d−1 while providing attachment sites and increasing the maximum cell yield compared to the control (1.49 × 106 and 1.01 × 106 cells mL−1 under activated carbon and control treatments, respectively). Oyster shells absorbed phosphate and did not increase the maximum cell yield. Our results suggest that submerged substrates that absorb nutrients may negatively affect the growth of attached diatoms. Therefore, when using the substrates for lake water restoration, attention must be paid to the growth of attached diatoms.

Insights into phenanthrene attenuation by hydroxyl radicals from reduced iron-bearing mineral oxygenation

The oxygenation of Fe(II)-bearing minerals for hydroxyl radicals (HO•) formation and contaminant attenuation receive increasing attention, while the mechanisms for specific Fe(II) species in manipulating HO• formation and contaminant attenuation are unclear. Herein, a total of four Fe(III)-bearing minerals were applied in the reduction-oxygenation processes to produce HO•. Results showed that the total HO• generated from the Fe-(oxyhydr)oxides were significantly higher than those from the Fe-silicates, with the order of goethite and hematite (~1500 μmol kg-1) > Fe-montmorillonite (~550 μmol kg-1) > chlorite (~120 μmol kg-1). The HO• formation was largely hinged on the reactive Fe(II) species, i.e., the surface-adsorbed/low-crystalline Fe(II) in the Fe-bearing minerals. For the co-incubation of minerals and phenanthrene, the concentrations of phenanthrene decreased from the initial 3.0 mg L-1 to 0.7 mg L-1 and 1.9 mg L-1 for Fe-montmorillonite and goethite, respectively, suggesting the HO• mediated by the Fe-montmorillonite was more conducive for phenanthrene attenuation. The goethite tended to promote the formation of free HO•, while the Fe-montmorillonite with interlayer structure can provide attachment sites for the surface-adsorbed/low-crystalline Fe(II), resulting in high potential for surface-bound HO• formation and phenanthrene attenuation. This study highlights the importance of Fe-bearing minerals in manipulating HO• formation, providing new insight into the removal of contaminants in ecosystems.

Cyclic AMP and biofilms reveal the synergistic proliferation strategy of Pseudomonas aeruginosa and Escherichia coli under the costimulation of high concentrations of microplastics and enrofloxacin

Microplastics (MPs) provide attachment sites for biofilm formation of microorganisms, which can promote their resistance to environmental stress has been proved. However, the effect of MPs on synergy survival among microorganisms under antibiotic stress remains unclear. In the present study, the proliferation of Escherichia coli and Pseudomonas aeruginosa was assessed under enrofloxacin stress with the influence of MPs. Here, MPs reduced the growth speed of E. coli and enhanced that of P. aeruginosa, especially at 12 h, but the final value of OD600 and CFU of both bacteria not be influenced. E. coli was enrofloxacin sensitive (MIC = 0.25 μg/mL), and a high MP concentration in the presence of enrofloxacin notably enhanced the biofilm formation ability of P. aeruginosa, but proliferation decreased. In the coculture system, the proliferation of E. coli (increased 1.42-fold) and P. aeruginosa (increased 1.06-fold) both increased under enrofloxacin stress (0.25 μg/mL) with high-concentration MP addition. P. aeruginosa may provide the biofilm matrix for E. coli to resist the stress of enrofloxacin. The high concentration of cyclic AMP secreted by E. coli may slightly inhibited biofilm formation, leading to a decrease in the fitness cost of P. aeruginosa; thus, the proliferation of P. aeruginosa increased. The present study is the first to show that MP combined with antibiotics stimulates the metabolic cooperation of bacteria to promote proliferation.

Do crocodilians have an air‐conditioning unit in their skulls? Experimental test of purported thermoregulatory function of the dorsal temporal fenestrae in the American alligator

The classic view of dorsal temporal fenestrae (DTFs) in diapsids posits that they provide attachment sites for jaw adductor muscles. A recent hypothesis suggested that DTFs in archosaurs may play a role in selective brain thermoregulation, but did not provide supporting experimental data. We tested this hypothesis in two years‐old juveniles of the American alligator. We used chronically implanted thermocouples to monitor brain (Tb) and core (Tc) temperatures in constrained but unanaesthetised animals during acute heat exposure. Animals were first equilibrated to either 15°C (n=9, body mass range 200‐563 g) or 30°C (n=6, body mass range 173‐362 g), and then exposed to a radiant heat source (a 75W incandescent light bulb suspended 20cm above the animal). As experimental treatment, we used insulating covers (custom‐made of adhesive foam tape and aluminium foil) to obscure either the DTFs or a corresponding skull surface in subsequent trials. We expected that obscuring the DTF (as opposed to covering the skull roof) would result in Tb rising more slowly in animals at 15°C (i.e., interfering with selective brain warming), and would result in Tb rising faster in animals at 30°C (i.e., interfering with selective brain cooling). We found no statistically significant differences in the rate of brain warming between DTF‐covered vs. skull‐covered treatments in animals at either 15°C (0.541°C/min vs. 0.683°C/min) or 30°C (0.356°C/min vs. 0.358°C/min). Our results suggest that DTFs, at least in small (<1 kg) alligators, do not function as thermal windows for heat exchange with the environment to afford them selective brain temperature control. However, given that the DTF surface area scales with positive allometry on brain mass (Mb^1.25) in the American alligator, further experiments are needed to determine whether DTFs acquire a thermoregulatory function in larger crocodilians.

SiRNA Mediated GSK3β Knockdown Targets Insulin Signaling Pathway and Rescues Alzheimer's Disease Pathology: Evidence from In Vitro and In Vivo Studies.

Sporadic Alzheimer's disease (sAD) is a progressive neurodegenerative disorder with dysfunctional insulin signaling and energy metabolism. Emerging evidence suggests impairments in brain insulin responsiveness, glucose utilization, and energy metabolism may be major causes of amyloid precursor protein mishandling. The support for this notion comes from the studies wherein streptozotocin (STZ) induced brain insulin resistance in rodent model resulted in sAD-like neuropathology with cognitive decline. Our previous study showed a compromised insulin signaling pathway, glucose uptake, glucose metabolism, and energy homeostasis in STZ-induced glial-neuronal coculture and in vivo model of sAD. Various components of insulin signaling pathway were examined to understand the metabolic correlation, and GSK3β was selected for gene knockdown strategy to reverse sAD pathology based on the data. In the present study, we have synthesized carboxylated graphene oxide (GO) nanosheets functionalized with PEG and subsequently with polyethylenimine (PEI) to provide attachment sites for GSK3β siRNA. Our results showed that siRNA mediated knockdown of the GSK3β gene reduced expression of amyloid pathway genes (APP and BACE1), which was further confirmed by reduced amyloid beta (Aβ) levels in the in vitro STZ-induced sAD model. GSK3β knockdown also restored insulin signaling, AMPK and Mapk3 pathway by restoring the expression of corresponding candidate genes in these pathways (IR, Glut1/3, Prkaa1/2, Mapk3, BDNF) that reflected improved cellular energy homeostasis, neuronal proliferation, differentiation, maturation, and repair. Behavioral data from Morris water maze (MWM), open field (OF), novel object recognition (NOR), Y maze, and radial arm maze (RAM) tests showed that 0.5 μg nanoformulation (GOc-PP-siRNAGSK3β) intranasally for 7 days improved spatial memory, rescued anxiety like behavior, improved visual and working memory, and rescued exploratory behavior in STZ-induced sAD rats. GSK3β silencing resulted in decreased BACE1 expression and prevented accumulation of Aβ in the cortex and hippocampus. These molecular findings with improved behavioral performances were further correlated with reduced amyloid beta (Aβ) and neurofibrillary tangle (NFTs) formation in the cortex and hippocampus of GOc-PP-siRNAGSK3β administered sAD rats. Therefore, it is conceivable from the present study that nanoparticle-mediated targeting of GSK3β in the sAD appears to be a promising strategy to reverse sAD pathology.

Discovery of a complex sclerotized sperm pump in Monotomidae (Coleoptera): Functional morphology and phylogenetic value.

In insects, a long ductus ejaculatorius surrounded by a muscular sheath transfers seminal fluids and sperms from the testes into the male copulatory organ, the aedeagus. In several unrelated coleopteran families, a section of the ductus has evolved to form a specialized pumping organ. The most complex forms of this "sperm pump" was known in Lepiceridae and two subfamilies of evolutionary distant Staphylinidae; in these groups two sclerotized funnels situated on ends of the sperm pump provide attachment sites for a remarkably robust compressor muscle. A sperm pump with two funnels and a previously unknown spiral ridge, representing the most complex sperm pumping apparatus among Coleoptera, is for the first time reported to occur in the superfamily Cucujoidea, family Monotomidae. The compressor muscle is particularly large, and the pump shows features more advanced than those in any other beetle. Not the entire section between funnels is compressed, but only a pair of specialized thin-walled, unsclerotized and resilin-rich regions within the pump. The spiral ridge stores mechanical energy to decompress the pump when the muscle relaxes, and provides a sclerotized scaffold for the entire structure. The pumps do not occur in all Monotomidae, but seem to be restricted to the subfamily Monotominae. Two distinct forms were found, each in a different tribe (with one notable exception; Mimemodes having a sperm pump typical of Monotomini, not Europini). Moreover, the shapes of the pumps were found to be species-specific. The phylogenetic value of this structure is discussed, as sperm pumps may help defining monophyletic lineages within this poorly studied family. An evolutionary scenario for a development of sperm pumps in Coleoptera from an undifferentiated ductus ejaculatorius to the most complex "monotomid form" is proposed, assuming several distinct stages exemplified by structures found in other beetle families.

Carbon quantum dots doped thin-film nanocomposite (TFN) membrane on macroporous ceramic hollow fiber support via one-step interfacial polymerization

The amino (NH2) modified carbon quantum dots (N-CDs) doped thin film nanocomposite (TFN) membranes were prepared on the macroporous ceramic hollow fiber (CHF) substrate with a pore size of about 300 nm through one-step interfacial polymerization (IP) process. The abundant hydroxyl, carboxyl, and amino groups of aqueous phase additives (N-CDs and polyvinyl alcohol (PVA)) provide attachment sites for ethylenediamine (EDA) to build a modified membrane structure. Molecular dynamics (MD) simulation was employed to study the diffusion process in IP. The results show that the addition of N-CDs reduced the EDA diffusion coefficient significantly from (4.58 ± 0.50) × 10−5 cm2/s to (1.44 ± 0.10) × 10−5 cm2/s. The wrinkled and ultra-thin polyamide (PA) layer with a thickness of 28 ± 3 nm was observed by the field-emission scanning electron microscopy (SEM). X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR), and dynamic contact angle were used to characterize the chemical structure and hydrophilicity. The effect of additives concentration on pervaporation (PV) performance for ethanol (EtOH) dehydration has been investigated systematically. The resultant membrane exhibited excellent performance with the total permeation flux of 3.15 kg·m−2·h−1 and separation factor of 1127. Besides, there was no significant performance decline during the 160 h long-term stability test, indicating that the membranes own the potential application in industry.

Metal Fractionation in Surface Sediments of the Brahmaputra River and Implications for Their Mobilization.

The Brahmaputra River is the largest tropical river in India that flows along the Himalayan regions and it is the lifeline of millions of people. Metal fractionation in the Brahmaputra River’s surface sediments and its correlation with turbidity are assessed in this study. The interaction between metal fractions and the overlying water is studied using multivariate statistical analyses. The strong positive correlation between NH4 of the overlying water and the exchangeable fractions in sediments signifies that the metals in the exchangeable fractions can be substituted by NH4. Subsequently, these metals can be released into the overlying water. The fluctuation in turbidity from 73 to 875 NTU indicates a large variation in the suspended matter concentration, and a higher concentration of suspended matter could provide attachment sites for pollutants such as metals. Significant variation in turbidity manifests a potentially high risk of pollution. In addition, the observation of local people along the Brahmaputra River turning its color to muddy indicates the need for continuous monitoring of water quality and an assessment of pollution is crucial. Although the Brahmaputra River’s risk assessment code is at low risk, the exchangeable fractions of Ni and Zn are present at all sites. Thus, the Brahmaputra River requires early preventive measures and management strategies to control metal pollution. This study contributes to an understanding of the fluctuation of turbidity of a tropical river. We provide baseline data for policymakers, and the importance of further intensive studies on metal pollution in the Himalayan Rivers is highlighted.

Insect Cuticular Chitin Contributes to Form and Function.

Chitin contributes to the rigidity of the insect cuticle and serves as an attachment matrix for other cuticular proteins. Deficiency of chitin results in abnormal embryos, cuticular structural defects and growth arrest. When chitin is not turned over during molting, the developing insect is trapped inside the old cuticle. Partial deacetylation of cuticular chitin is also required for proper laminar organization of the cuticle and vertical pore canals, molting, and locomotion. Thus, chitin and its modifications strongly influence the structure of the exoskeleton as well as the physiological functions of the insect. Internal tendons and specialized epithelial cells called "tendon cells" that arise from the outer layer of epidermal cells provide attachment sites at both ends of adult limb muscles. Membrane processes emanating from both tendon and muscle cells interdigitate extensively to strengthen the attachment of muscles to the extracellular matrix (ECM). Protein ligands that bind to membrane-bound integrin complexes further enhance the adhesion between muscles and tendons. Tendon cells contain F-actin fiber arrays that contribute to their rigidity. In the cytoplasm of muscle cells, proteins such as talin and other proteins provide attachment sites for cytoskeletal actin, thereby increasing integrin binding and activation to mechanically couple the ECM with actin in muscle cells. Mutations in integrins and their ligands, as well as depletion of chitin deacetylases, result in defective locomotion and muscle detachment from the ECM. Thus, chitin in the cuticle and chitin deacetylases strongly influence the shape and functions of the exoskeleton as well as locomotion of insects.

Interaction between prostate cancer cells and prostate fibroblasts promotes accumulation and proteolytic processing of basement membrane proteins.

Tumor microenvironment or stroma has the potency to regulate the behavior of malignant cells. Fibroblast-like cells are abundant in tumor stroma and they are also responsible for the synthesis of many extracellular matrix components. Fibroblast-cancer cell interplay can modify the functions of both cell types. We applied mass spectrometry and proteomics to unveil the matrisome in 3D spheroids formed by DU145 prostate cancer cells, PC3 prostate cancer cells, or prostate-derived fibroblasts. Similarly, DU145/fibroblast and PC3/fibroblast coculture spheroids were also analyzed. Western blot analysis and immunofluorescence were used to confirm the presence of specific proteins in spheroids. Cancer dissemination was studied by utilizing "out of spheroids" migration and invasion assays. In the spheroid model cancer cell-fibroblast interplay caused remarkable changes in the extracellular matrix and accelerated the invasion of DU145 cells. Fibroblasts produced structural matrix proteins, growth factors, and matrix metalloproteinases. In cancer cell/fibroblast cocultures basement membrane components, including laminins (α3, α5, β2, and β3), heparan sulfate proteoglycan (HSPG2 gene product), and collagen XVIII accumulated in a prominent manner when compared with spheroids that contained fibroblasts or cancer cells only. Furthermore, collagen XVIII was intensively processed to different endostatin-containing isoforms by cancer cell-derived cathepsin L. Fibroblasts can promote carcinoma cell dissemination by several different mechanisms. Extracellular matrix and basement membrane proteins provide attachment sites for cell locomotion promoting adhesion receptors. Growth factors and metalloproteinases are known to accelerate cell invasion. In addition, cancer cell-fibroblast interplay generates biologically active fragments of basement membrane proteins, such as endostatin.