Adhesion Capacity Research Articles

Seminal plasma inhibits Chlamydia trachomatis infection in vitro, and may have consequences on mucosal immunity

Seminal plasma (SP) is the main vector of C. trachomatis (CT) during heterosexual transmission from male to female. It has immunomodulatory properties and impacts the susceptibility to HIV-1 infection, but its role has not been explored during CT infection. In the female reproductive tract (FRT), CT infection induces cytokine production and neutrophil recruitment. The role of neutrophils during CT infection is partially described, they could be at the origin of the pathology observed during CT infection. During this study, we developed an experimental in vitro model to characterize the impact of CT infection and SP on endocervical epithelial cell immune response in the FRT. We also studied the impact of the epithelial cell response on neutrophil phenotype and functions. We showed that the production by epithelial cells of pro-inflammatory cytokines increased during CT infection. Moreover, the pool of SP as well as individuals SP inhibited CT infection in a dose-dependent manner. The pool of SP inhibited cytokine production in a dose-dependent manner. The pool of SP altered gene expression profiles of infected cells. The culture supernatants of cells infected or not with CT, in presence or not of the pool of SP, had an impact on neutrophil phenotype and functions: they affected markers of neutrophil maturation, activation and adhesion capacity, as well as the survival, ROS production and phagocytosis ability. This study proposes a novel approach to study the impact of the environment on the phenotype and functions of neutrophils in the FRT. It highlights the impact of the factors of the FRT environment, in particular SP and CT infection, on the mucosal inflammation and the need to take into account the SP component while studying sexually transmitted infections during heterosexual transmission from male to female.

Calcium Rescues Streptococcus pneumoniae D39 ΔmntE Manganese-Sensitive Growth Phenotype.

Calcium (Ca2+) functions as a universal signal messenger in eukaryotes but in bacteria, the physiological roles for Ca2+ are limited. Here, we examine the role of Ca2+ in Streptococcus pneumoniae during manganese (Mn2+) intoxication. S. pneumoniae mntE mutants, lacking the Mn2+ efflux transporter, exhibit impaired growth due to accumulation of Mn2+ when exposed to elevated exogenous Mn2+. This Mn2+-sensitive growth defect is restored to wild-type growth level by exogenous Ca2+, in a Ca2+-dependent manner. Despite growth restoration of the mntE mutant to wild-type levels, cellular Mn2+ remains elevated in this strain. Bacterial capsule production is also increased for the mntE mutant, resulting in reduced adherence capacity to surfaces and poor biofilm formation, which is consistent with it experiencing Mn2+ intoxication. Ca2+ presence did not significantly impact bacterial capsule production or biofilm formation. Further analysis of the cell morphology demonstrates that Ca2+ contributes to cell division and reduces cell chain lengths. Together, these data describe the first role of Ca in S. pneumoniae that has potential implications in bacterial virulence since Ca affects cell division and likely Mn2+-associated cellular processes.

Investigating the different effects of soybean proteins and peptides on the adhesion capacity of Limosilactobacillus reuteri LR08 and Escherichia coli JCM1649

Soybean proteins and peptides cooperated Limosilactobacillus reuteri (L. reuteri) in various ways to inhibit Escherichia coli (E. coli), but their impact on adhesion to intestinal cells remains unclear. This study investigated the adhesion properties of L. reuteri LR08 and E. coli JCM1649 regulated by soybean proteins and peptides. Digested soybean proteins (dpro) significantly enhanced L. reuteri adhesion and increased surface hydrophobicity more effectively than digested peptides (dpep) during early logarithmic growth. Dpro also improved L. reuteri biofilm formation and auto-aggregation in the stationary phase. Conversely, dpep markedly reduced E. coli adhesion to HT-29 cells, diminishing its biofilm formation and surface properties. The inhibitory effect of dpro on E. coli adhesion was weaker than that of dpep. These results highlight the diverse modulation of L. reuteri and E. coli adhesion by dpep and dpro, providing a theoretical basis for the use of probiotics to alleviate foodborne intestinal infections.

Lattice-designed 3D printing of gluten-free pasta incorporated with xanthan gum for the elderly food

The use of xanthan gum (XG) has been reported to soften the texture of gluten-free pasta (GFP), making it an ideal food for the elderly with swallowing difficulties. Designing pasta shapes can enhance the suitability of sauces, improving sensory properties. This study aimed to investigate the optimal amount of XG for softening the texture of GFP. Three-dimensional (3D) printing was used to create lattice design shapes of the soft GFP, and sauce adhesion capacity (SAC) was investigated. The viscoelastic properties and yield stress values of the GFP dough significantly increased with higher XG contents (0.25%–2%) (p < 0.05), improving ink printability. The X-1% sample showed a decrease in the storage modulus (G’) (representing solid-like behavior) curve when the temperature increased from 68 °C, correlating with its lower hardness (5.11 × 104 ± 480 N/m2), which almost matched level 2 as the soft solid food that can be mashed with gums. This also agreed with its reduction in water-holding capacity (WHC) and its larger microstructural porosities. The SAC test demonstrated a significant relationship between 3D lattice design shapes and sauce viscosity, concluding that high- or low-viscous sauces may be suitable for the larger or smaller size of interior hole designs, respectively. This study provides guidance for developing novel 3D-printed GFP with a soft texture specifically designed to improve the mealtime experience for the elderly.

AcsS Negatively Regulates the Transcription of type VI Secretion System 2 Genes in Vibrio parahaemolyticus.

The type VI secretion system 2 (T6SS2) gene cluster of Vibrio parahaemolyticus comprises three operons: VPA1027-1024, VPA1043-1028, and VPA1044-1046. AcsS is a LysR-like transcriptional regulator that play a role in activating flagella-driven motility in V. parahaemolyticus. However, its potential roles in other cellular pathways remain poorly understood. In this study, we conducted a series of experiments to investigate the regulatory effects of AcsS on the transcription of VPA1027 (hcp2), VPA1043, and VPA1044. The findings revealed that AcsS indirectly inhibits the transcription of these genes. Additionally, deletion of acsS resulted in enhanced adhesion of V. parahaemolyticus to HeLa cells. However, disruption of T6SS2 alone or in conjunction with AcsS significantly diminished the adhesion capacity of V. parahaemolyticus to HeLa cells. Therefore, it is suggested that AcsS suppresses cell adhesion in V. parahaemolyticus by downregulating the transcription of T6SS2 genes.

Evaluation of the probiotic, anti-bacterial, anti-biofilm, and safety properties of Lacticaseibacillusparacasei B31-2

Lacticaseibacillusparacasei is commonly present in the gut flora of healthy individuals and in various fermented foods, such as yogurt, and other dairy items. This strain is frequently incorporated into dietary supplements and functional foods. In this study, L.paracasei B31-2 was isolated from local yogurt, and its probiotic, anti-microbial, anti-biofilm, and safety properties were investigated. The L.paracasei B31-2 exhibited robust resilience to acidic conditions, bile salts, and the challenges of the gastrointestinal environment. Its cell surface hydrophobicity measured at 55.42%, along with notable co-aggregation (25.80%), auto-aggregation (42.50%), and adhesion capacity (12.60%). Moreover, L.paracasei B31-2 did not exhibit any hemolytic/DNase effect and did not generate biogenic amines. The strain exhibited varying susceptibility levels, with the highest susceptibility to nitrofurantoin (27.50 mm) and the lowest to ampicillin (13.60 mm). Treatment with cell-free supernatants of L.paracasei B31-2 resulted in a reduction of biofilm formation by Listeriamonocytogenes. The second section of this study evaluated the Gaussian Process Regression (GPR) model for predicting probiotic viability. The results demonstrated that the GPR model could predict probiotic viability with high accuracy. The findings suggest that L.paracasei B31-2 has promising potential for health-improving purposes, potentially offering protective effects against specific pathogens and contributing to gastrointestinal health.

A low-pollution surface modification system for improving the adhesion of polycarbonate

In the present study, the surface adhesion capacity of polycarbonate (PC) has been improved by using a low-pollution surface modification system that includes alkaline potassium ferrate (K2FeO4). The effects of environmentally friendly swelling conditions, NaOH and K2FeO4 contents, and other modification conditions on the PC surface topography, hydrophilicity, and surface roughness were then primarily studied. The modification resulted in an improvement of the hydrophilic property of the PC surface. There was a significant reduction in the surface contact angle from 97.6° to 34.1°. A considerable increase in the PC surface’s average surface roughness (Ra) was also observed, which increased from 2 nm to 209 nm. Meanwhile, after chemical copper plating, the maximum peel strength between the PC resin and copper layer reached 1.13 kN/m. Furthermore, infrared absorption spectroscopy (FT–IR) and X–ray photoelectron spectroscopy (XPS) was used in the analyses of the surface chemical structure of the PC substrate, both prior to and after surface treatments. The results indicated that the modification of the surface led to increased hydrophilic groups on the PC surface, which was advantageous for the subsequent PC treatments (involving chemical copper plating). In short, the PC surface modification increased surface roughness and surface hydrophilicity, which improved the bonding between the chemically plated copper layer and the PC substrate.

Axonal Growth and Fasciculation of Spinal Neurons Promoted by Aldynoglia in Alkaline Fibrin Hydrogel: Influence of Tol-51 Sulfoglycolipid.

Traumatic spinal cord injury (tSCI) has complex pathophysiological events that begin after the initial trauma. One such event is fibroglial scar formation by fibroblasts and reactive astrocytes. A strong inhibition of axonal growth is caused by the activated astroglial cells as a component of fibroglial scarring through the production of inhibitory molecules, such as chondroitin sulfate proteoglycans or myelin-associated proteins. Here, we used neural precursor cells (aldynoglia) as promoters of axonal growth and a fibrin hydrogel gelled under alkaline conditions to support and guide neuronal cell growth, respectively. We added Tol-51 sulfoglycolipid as a synthetic inhibitor of astrocyte and microglia in order to test its effect on the axonal growth-promoting function of aldynoglia precursor cells. We obtained an increase in GFAP expression corresponding to the expected glial phenotype for aldynoglia cells cultured in alkaline fibrin. In co-cultures of dorsal root ganglia (DRG) and aldynoglia, the axonal growth promotion of DRG neurons by aldynoglia was not affected. We observed that the neural precursor cells first clustered together and then formed niches from which aldynoglia cells grew and connected to groups of adjacent cells. We conclude that the combination of alkaline fibrin with synthetic sulfoglycolipid Tol-51 increased cell adhesion, cell migration, fasciculation, and axonal growth capacity, promoted by aldynoglia cells. There was no negative effect on the behavior of aldynoglia cells after the addition of sulfoglycolipid Tol-51, suggesting that a combination of aldynoglia plus alkaline fibrin and Tol-51 compound could be useful as a therapeutic strategy for tSCI repair.

Mussel-Inspired Injectable Adhesive Hydrogels for Biomedical Applications.

The impressive adhesive capacity of marine mussels has inspired various fascinating designs in biomedical fields. Mussel-inspired injectable adhesive hydrogels, as a type of promising mussel-inspired material, have attracted much attention due to their minimally invasive property and desirable functions provided by mussel-inspired components. In recent decades, various mussel-inspired injectable adhesive hydrogels have been designed and widely applied in numerous biomedical fields. The rational incorporation of mussel-inspired catechol groups endows the injectable hydrogels with the potential to exhibit many properties, including tissue adhesiveness and self-healing, antimicrobial, and antioxidant capabilities, broadening the applications of injectable hydrogels in biomedical fields. In this review, we first give a brief introduction to the adhesion mechanism of mussels and the characteristics of injectable hydrogels. Further, the typical design strategies of mussel-inspired injectable adhesive hydrogels are summarized. The methodologies for integrating catechol groups into polymers and the crosslinking methods of mussel-inspired hydrogels are discussed in this section. In addition, we systematically overview recent mussel-inspired injectable adhesive hydrogels for biomedical applications, with a focus on how the unique properties of these hydrogels benefit their applications in these fields. The challenges and perspectives of mussel-inspired injectable hydrogels are discussed in the last section. This review may provide new inspiration for the design of novel bioinspired injectable hydrogels and facilitate their application in various biomedical fields.

Longevous ionogels with high strength, conductivity, adhesion and thermoplasticity

The longevity of flexible electronics substantially influences their viability for practical use. At present, the service life of pliable devices utilizing conductive gels is frequently compromised due to factors inclusive but not limited to solvent loss. Taking cues from the steadfast structure of human tissues, we hereby delineate a solvent-assisted strategy to fabricate ionogels, predicated on a supramolecular network of hydrogen bonds. Upon subjecting these ionogels to realistic operational environments, it has been empirically ascertained that they maintain a steadfast mechanical and electrical consistency for a minimum duration of 22 months. In terms of dynamic stretchability, they effortlessly endure one million stretch cycles, even when faced with a notch. The induction of a supramolecular structure within the ionogel not only confers exceptional mechanical attributes but also simultaneously enhances conductivity, a feat paralleled by few recent explorations. Furthermore, these ionogels boast of superior anti-freezing and adhesive characteristics, including a toughness extending up to 17.96 MJ/m3 at an ultra-low temperature of −50 °C, and an adhesive capacity permitting movement and bearing of items weighing over 10,000 times its own weight, the lap-shear strength can reach 30.2 kPa. Intriguingly, these gels demonstrate thermoplastic behavior, which facilitates their easy reshaping into diverse forms. Such compelling attributes amplify the potential of supramolecular ionogels, positioning them as formidable contenders for flexible electronics in stringent and challenging scenarios.

Functional Cyperus esculentus L. Cookies Enriched with the Probiotic Strain Lacticaseibacillus rhamnosus SL42.

This study presents for the first time functional cookies for diabetics made with 100% organic Cyperus esculentus L. flour, either plain or enhanced with 5% polyfloral honey syrup containing the probiotic strain Lacticaseibacillus rhamnosus SL42. The flour's chemical composition and rheological and functional properties were analyzed, and 33 diabetic and semi-naive panelists assessed the cookies' sensory properties. MRS-cys agar cultures and SEM analysis evaluated SL42 survival and adhesion capacity over 21 days at 25 °C. Results showed that the flour and its extracts are rich in polyphenols and flavonoids, indicating strong antioxidant and antibacterial properties. Both cookie types met international standards when compared to commercial cookies and had similar physical properties. Sensory evaluation on day 1 revealed higher quality indicators for honey syrup-enriched cookies, but after 15 days, control cookies were preferred. The CIE LAB analysis confirmed the dietetic flour's typical dark color, with honey syrup-enriched cookies being darker. Despite textural differences, both cookies maintained detectable crispness over storage. Honey syrup-enriched cookies effectively carried L. rhamnosus SL42, remaining viable at 6.43 Log CFU per cookie after 21 days and adhering to the cookie's surface, as confirmed by SEM analysis. Further research is recommended to better understand the therapeutic value of these cookies.

Cardiovascular risk in ANCA-associated vasculitis: Monocyte phenotyping reveals distinctive signatures between serological subsets

Background and aimsAnti-neutrophil cytoplasmic antibodies (ANCA)-associated vasculitides (AAV) is associated with an increased cardiovascular risk, particularly the myeloperoxidase AAV serotype (MPO-AAV). Distinct alterations in monocyte phenotypes may cause accelerated atherosclerotic disease in AAV. MethodsA cohort including 43 AAV patients and 19 healthy controls was included for downstream analyses. Extensive phenotyping of monocytes and monocyte-derived macrophages was performed using bulk RNA-sequencing and flow cytometry. An in vitro transendothelial migration assay reflecting intrinsic adhesive and migratory capacities of monocytes was employed. Subsequent sub-analyses were performed to investigate differences between serological subtypes. ResultsMonocyte subset analysis showed increased classical monocytes during active disease, whereas non-classical monocytes were decreased compared to healthy controls (HC). RNA-sequencing revealed upregulation of distinct inflammatory pathways and lipid metabolism-related markers in monocytes of active AAV patients. No differences were detected in the intrinsic monocyte adhesion and migration capacity. Compared to proteinase-3(PR3)-AAV, monocytes of MPO-AAV patients in remission expressed genes related to inflammation, coagulation, platelet-binding and interferon signalling, whereas the expression of chemokine receptors indicative of acute inflammation and monocyte extravasation (i.e., CCR2 and CCR5) was increased in monocytes of PR3-AAV patients. During active disease, PR3-AAV was linked with elevated serum CRP and increased platelet counts compared to MPO-AAV. ConclusionsThese findings highlight changes in monocyte subset composition and activation, but not in the intrinsic migration capacity of AAV monocytes. MPO-AAV monocytes are associated with sustained upregulation of inflammatory genes, whereas PR3-AAV monocytes exhibit chemokine receptor upregulation. These molecular changes may play a role in elevating cardiovascular risk as well as in the underlying pathophysiology of AAV.

Phenotypic and Genotypic Characterization of Resistance and Virulence Markers in Candida spp. Isolated from Community-Acquired Infections in Bucharest, and the Impact of AgNPs on the Highly Resistant Isolates.

This study aimed to determine, at the phenotypic and molecular levels, resistance and virulence markers in Candida spp. isolated from community-acquired infections in Bucharest outpatients during 2021, and to demonstrate the efficiency of alternative solutions against them based on silver nanoparticles (AgNPs). A total of 62 Candida spp. strains were isolated from dermatomycoses and identified using chromogenic culture media and MALDI-TOF MS, and then investigated for their antimicrobial resistance and virulence markers (VMs), as well as for metabolic enzymes using enzymatic tests for the expression of soluble virulence factors, their biofilm formation and adherence capacity on HeLa cells, and PCR assays for the detection of virulence markers and the antimicrobial activity of alternative solutions based on AgNPs. Of the total of 62 strains, 45.16% were Candida parapsilosis; 29.03% Candida albicans; 9.67% Candida guilliermondii; 3.22% Candida lusitaniae, Candia pararugosa, and Candida tropicalis; and 1.66% Candida kefyr, Candida famata, Candida haemulonii, and Candida metapsilosis. Aesculin hydrolysis, caseinase, and amylase production were detected in the analyzed strains. The strains exhibited different indices of adherence to HeLa cells and were positive in decreasing frequency order for the LIP1, HWP1, and ALS1,3 genes (C. tropicalis/C. albicans). An inhibitory effect on microbial growth, adherence capacity, and on the production of virulence factors was obtained using AgNPs. The obtained results in C. albicans and Candida non-albicans circulating in Bucharest outpatients were characterized by moderate-to-high potential to produce VMs, necessitating epidemiological surveillance measures to minimize the chances of severe invasive infections.

Characteristics and functional analysis of a novel mannose receptor in Penaeus vannamei

The mannose receptor (MR) plays a key role in the innate immune system as a pattern recognition receptor. Here, a novel type of mannose receptor, named PvMR2, was identified from Penaeus vannamei (P. vannamei). The PvMR2 coding sequence (CDS) obtained was 988 base pairs in length, encoding a protein consisting of 328 amino acids. This protein includes a signal peptide and two classical C-type lectin domains (CTLD). Quantitative real-time PCR showed that PvMR2 was distributed in all detected tissues, with the highest levels in the intestines and stomach. Following a bacterial challenge with Vibrio anguillarum (V. anguillarum), PvMR2 showed significant up-regulation in both the intestines and stomach of shrimp. To validate the function of PvMR2, recombinant proteins were extracted and purified using a His-tag. The resulting rPvMR2 demonstrated binding capability with lipopolysaccharides (LPS) and peptidoglycan (PGN) in a dose-dependent manner, affirming its binding affinity. The purified rPvMR2 demonstrated calcium-independent binding activity towards both Gram-positive bacteria (V. anguilliarum and Vibrio parahaemolyticus) and Gram-negative bacteria (Escherichia coli and Aeromonas Veronii). Antibacterial assays confirmed that rPvMR2 inhibits bacterial growth. Intestinal adhesion and adhesion inhibition experiments confirmed that the rPvMR2 can be used to reduce the adhesion capacity of harmful bacteria in the gut. Phagocytosis experiments have shown that rPvMR2 promotes phagocytosis in hemocytes and protects the host from external infection. Treatment with recombinant PvMR2 significantly bolstered bacterial clearance within the hemolymph and markedly augmented shrimp survival post-infection with V. anguillarum. These results suggest that PvMR2 has agglutination, growth inhibition, adhesion inhibition, clearance promotion, and phagocytosis effects on harmful bacteria, and plays a crucial role in the antimicrobial immune response of P. vannamei.

Ex-vivo investigation of probiotic bacterial adhesion to the intestinal mucus

Recent research has promoted considerable interest in the potential health benefits of the new generation of probiotics. Despite the abundance of probiotic supplements, their adhesion and thereby colonization in the intestinal tract of the host, a determining factor of probiotic efficacy, remains questionable. Indeed, the gastrointestinal tract, a multi-component and complex system, obscures the comprehensive understanding of the probiotic adhesion mechanism. This study aimed to investigate the adhesion capacity of probiotic bacteria using two ex-vivo approaches that were specifically developed to investigate the bacteria-mucus agglomeration and the viable adhesion to intestinal mucus. Five probiotic bacterial strains including Escherichia coli, Lactiplantibacillus plantarum, Faecalibacterium duncaniae, Bifidobacterium longum, and Bifidobacterium longum str. infantis were selected for the investigation. In that context, higher adhesion to mucus was demonstrated by E. coli, L. plantarum, and B. infantis, emphasizing strain-specific differences. While total agglomeration capacity ranged from 8 % to 82 %, actual viable adhesion to mucus remained rather low (0.6 %–2.9 %). SEM images revealed that morphological characteristics, chain and/or cluster forming ability, as well as the presence of surface exopolysaccharides, might have an impact on bacterial adhesion. This study contributes knowledge on probiotic adhesion as well as simple and effective ex-vivo approaches to investigate the bacterial adhesion to the intestinal mucus, which is prerequisite for further colonization in the gut of the host.

Characterization of nuvita biosearch center (NBC) isolated lactic acid bacteria strains from human origin and determination of growth kinetic profiles of selected cultures under bioreactor

BackgorundIn recent years, there has been an increasing interest in the field of research into the isolation and characterization of probiotics in the prevention of diseases and the need to maintain the continuity of healthy microbiota. Therefore, the aim of this study is to isolate and identify bacteria found in maternal colostrum, breast milk, adult and infant feces, analyze possible probiotic potential, and reveal the developmental kinetics of selected strains.ResultsWe isolated 40 bacterial species from 4 different sources and identified 19 bacteria in the form of bacilli through molecular biology and carried out studies with 11 of them. Five of the selected strains showed the better results considering bile salt resistance and ability to survive at different pH and antimicrobial effect. When the adhesion capacity in cell culture is examined, the better 2 strains are; Lactobacillus pontis ZZ6780 and Lactobacillus reuteri NBC2680 were selected and the growth kinetics of these strains were demonstrated at the 3 L bioreactor scale. Finally, the growth kinetics of selected strains were determined and the maximum specific growth rate of selected Lactobacillus pontis ZZ6780 and Lactobacillus reuteri NBC2680 was calculated as 0.412 h− 1 and 0.481 h− 1, respectively. In addition, the dry cell matter amounts were found to be and 4.45 g/L and 5.23 g/L, respectively.ConclusionThis study established the groundwork for the selection of safety probiotics for the development and application of LAB. It is thought that the two strains obtained as a result of this study can be considered as potential probiotic strains in the food, pharmaceutical and cosmetic industries.

Gallic acid exerts antibiofilm activity by inhibiting methicillin-resistant Staphylococcus aureus adhesion

Methicillin-resistant Staphylococcus aureus (MRSA) is a serious threat to patients with nosocomial infections, and infection is strongly associated with biofilm formation. Gallic acid (GA) is a natural bioactive compound found in traditional Chinese medicines that exerts potent antimicrobial activity. However, the anti-MRSA biofilm efficacy of GA remained to be determined. This study investigated the antimicrobial activities of GA against MRSA and the mechanisms involved. The results revealed the significant antibacterial and antibiofilm activities of GA. The minimal inhibitory concentration of GA against MRSA was 32 μg/mL and a growth curve assay confirmed the significant inhibitory effect of GA on planktonic MRSA. Crystal violet and XTT assays showed that 8 µg/mL GA effectively inhibited the formation of new biofilms and disrupted existing biofilms by reducing both biofilm biomass and metabolic activities. Alkaline phosphatase and β-galactosidase leakage assays and live/dead staining provided evidence that GA disrupted the integrity of bacterial cell walls and membranes within the biofilm. Scanning electron microscopy observations showed that GA significantly inhibited bacterial adhesion and aggregation, affecting the overall structure of the biofilm. Bacterial adhesion, polysaccharide intercellular adhesion (PIA) production and real-time quantitative PCR assay confirmed that GA inhibited bacterial adhesion, PIA synthesis, and the expression of icaAD and sarA. These results suggested that GA inhibited biofilm formation by inhibiting the expression of sarA, then downregulating the expression of icaA and icaD, thereby reducing the synthesis of PIA to attenuate the adhesion capacity of MRSA. GA is therefore a promising candidate for development as a pharmaceutical agent for the prevention and treatment of bacterial infections caused by MRSA.

Dry Powder Inhaler Formulation of Lactobacillus rhamnosus GG Targeting Pseudomonas aeruginosa Infection in Bronchiectasis Maintenance Therapy.

The inhaled delivery of lactic acid bacteria (LAB) probiotics has been demonstrated to exert therapeutic benefits to the lungs due to LAB's immunomodulatory activities. The development of inhaled probiotics formulation, however, is in its nascent stage limited to nebulized LAB. We developed a dry powder inhaler (DPI) formulation of lactobacillus rhamnosus GG (LGG) intended for bronchiectasis maintenance therapy by spray freeze drying (SFD). The optimal DPI formulation (i.e., LGG: mannitol: lactose: leucine = 35: 45: 15: 5 wt.%) was determined based on the aerosolization efficiency (86% emitted dose and 26% respirable fraction) and LGG cell viability post-SFD (7 log CFU/mL per mg powder). The optimal DPI formulation was evaluated and compared to lyophilized naked LGG by its (1) adhesion capacity and cytotoxicity to human lung epithelium cells (i.e., A549 and 16HBE14o- cells) as well as its (2) effectiveness in inhibiting the growth and adhesion of Pseudomonas aeruginosa to lung cells. The optimal DPI of LGG exhibited similar non-cytotoxicity and adhesion capacity to lung cells to naked LGG. The DPI of LGG also inhibited the growth and adhesion of P. aeruginosa to the lung cells as effectively as the naked LGG. The present work established the feasibility of delivering the LAB probiotic by the DPI platform without adversely affecting LGG's anti-pseudomonal activities.

Multifunctional Hydrogel Based on Silk Fibroin Promotes Tissue Repair and Regeneration

AbstractThe creation of functional hydrogels with robust load‐bearing capacity adaptable to complex tissue regeneration remains challenging. Silk fibroin (SF) is a natural biomaterial with excellent mechanical strength and cell adhesion capacity, possessing tremendous potential to solve the aforementioned dilemma. The excellent biodegradability and biocompatibility and the molecular structure with multiple modifiable moieties provide opportunities for the injectability and multifunctionality of hydrogels. Furthermore, the incorporation of other polymers or active ingredients can improve the basic properties, confer biological activities and pharmacological effects, and provide the prerequisites for hydrogels to fulfill specific requirements. Therefore, SF‐based hydrogels are widely applied in tissue repair and regeneration, especially in bone, skin, nerve, liver, myocardium, and cornea, which have effectively addressed the challenges of scaffolds' lack of cell adhesion sites, excessive degradation, as well as the lack of efficient, long‐lasting antimicrobial properties. This review outlines the properties of SF, discusses the types of materials commonly used in the preparation of hydrogels and their characteristics, and describes the current construction methods of SF hydrogels. Simultaneously, recent advancements in applying SF‐based multifunctional hydrogels within biological tissues are explored, with a focus on their role in tissue repair, highlighting the repair mechanism of SF based on bone and skin.

Presence and Role of the Type 3 Fimbria in the Adherence Capacity of Enterobacter hormaechei subsp. hoffmannii.

Enterobacter hormaechei, one of the species within the Enterobacter cloacae complex, is a relevant agent of healthcare-associated infections. In addition, it has gained relevance because isolates have shown the capacity to resist several antibiotics, particularly carbapenems. However, knowledge regarding colonization and virulence mechanisms of E. hormaechei has not progressed to the same extent as other Enterobacteriaceae species as Escherichia coli or Klebsiella pneumoniae. Here, we describe the presence and role of the type 3 fimbria, a chaperone-usher assembled fimbria, which was first described in Klebsiella spp., and which has been detected in other representatives of the Enterobacteriaceae family. Eight Chilean E. cloacae isolates were examined, and among them, four E. hormaechei isolates were found to produce the type 3 fimbria. These isolates were identified as E. hormaechei subsp. hoffmannii, one of the five subspecies known. A mutant E. hormaechei subsp. hoffmannii strain lacking the mrkA gene, encoding the major structural subunit, displayed a significantly reduced adherence capacity to a plastic surface and to Caco-2 cells, compared to the wild-type strain. This phenotype of reduced adherence capacity was not observed in the mutant strains complemented with the mrkA gene under the control of an inducible promoter. Therefore, these data suggest a role of the type 3 fimbria in the adherence capacity of E. hormaechei subsp. hoffmannii. A screening in E. hormaechei genomes contained in the NCBI RefSeq Assembly database indicated that the overall presence of the type 3 fimbria is uncommon (5.94-7.37%), although genes encoding the structure were detected in representatives of the five E. hormaechei subspecies. Exploration of complete genomes indicates that, in most of the cases, the mrkABCDF locus, encoding the type 3 fimbria, is located in plasmids. Furthermore, sequence types currently found in healthcare-associated infections were found to harbor genes encoding the type 3 fimbria, mainly ST145, ST78, ST118, ST168, ST66, ST93, and ST171. Thus, although the type 3 fimbria is not widespread among the species, it might be a determinant of fitness for a subset of E. hormaechei representatives.