Microbial degradation of low-density polyethylene (LDPE) and polystyrene using Bacillus cereus (OR268710) isolated from plastic-polluted tropical coastal environment

The study focused on marine bacteria, specifically Bacillus cereus, sourced from heavily polluted coastal areas in Tamil Nadu, aiming to assess their efficacy in degrading low-density polyethylene (LDPE) and polystyrene over a 42-day period. When LDPE and polystyrene films were incubated with Bacillus cereus, they exhibited maximum weight losses of 4.13 ± 0.81 % and 14.13 ± 2.41 %, respectively. Notably, polystyrene exhibited a higher reduction rate (0.0036 day-1) and a shorter half-life (195.29 days). SEM images of the treated LDPE and polystyrene unveiled surface erosion with cracks. The energy dispersive X-ray (EDX) analysis revealed elevated carbon content and the presence of oxygen in the treated LDPE and polystyrene films. The ATR-FTIR spectra exhibited distinctive peaks corresponding to functional groups, with observable peak shifts in the treated films. Notable increases were detected in carbonyl, internal double bond, and vinyl indices across all treated groups. Additionally, both treated LDPE and polystyrene showed reduced crystallinity. This research sheds light on Bacillus cereus (OR268710) biodegradation capabilities, emphasizing its potential for eco-friendly waste management in coastal regions.

Line-field confocal optical coherence tomography, a novel non-invasive tool for the diagnosis of onychomycosis

BACKGROUND AND OBJECTIVES

Onychomycosis is common and important to distinguish from other nail diseases. Rapid and accurate diagnosis is necessary for optimal patient treatment and outcome. Non-invasive diagnostic tools have increasing potential for nail diseases including onychomycosis. This study evaluated line-field confocal optical coherence tomography (LC-OCT) as a rapid non-invasive tool for diagnosing onychomycosis as compared to confocal laser scanning microscopy (CLSM), optical coherence tomography (OCT), and conventional methods.

PATIENTS AND METHODS

In this prospective study 86 patients with clinically suspected onychomycosis and 14 controls were examined using LC-OCT, OCT, and CLSM. KOH-preparation, fungal culture, PCR, and histopathology were used as comparative conventional methods.

RESULTS

LC-OCT had the highest sensitivity and negative predictive value of all methods used, closely followed by PCR and OCT. Specificity and positive predictive value of LC-OCT were as high as with CLSM, while OCT scored much lower. The gold standard technique, fungal culture, showed the lowest sensitivity and negative predictive value. Only PCR and culture allowed species differentiation.

CONCLUSIONS

LC-OCT enables quick and non-invasive detection of onychomycosis, with advantages over CLSM and OCT, and similar diagnostic accuracy to PCR but lacking species differentiation. For accurate nail examination, LC-OCT requires well-trained and experienced operators.

Konfokale Line-Field optische Kohärenztomographie, ein innovatives nichtinvasives Instrument zur Diagnose der Onychomykose: Line-field confocal optical coherence tomography, a novel non-invasive tool for the diagnosis of onychomycosis

Hintergrund und Ziele

Onychomykose ist weit verbreitet und sollte von anderen Nagelerkrankungen unterschieden werden. Eine rasche und genaue Diagnostik ist für die optimale Behandlung des Patienten und ein bestmögliches Ergebnis erforderlich. Nichtinvasive Techniken haben ein wachsendes Potenzial bei der Diagnose von Nagelerkrankungen, einschließlich Onychomykose. In dieser Studie wurde die konfokale Line‐Field optische Kohärenztomographie (LC‐OCT) als schnelle nichtinvasive Methode zur Diagnose von Onychomykose im Vergleich zur konfokalen Laserscanmikroskopie (KLM), optischen Kohärenztomographie (OCT) und konventionellen Methoden bewertet.

Patienten und Methodik

In dieser prospektiven Studie wurden 86 Patienten mit klinischem Verdacht auf Onychomykose und 14 Kontrollen mittels LC‐OCT, OCT und KLM untersucht. KOH‐Präparation, Pilzkultur, PCR und Histopathologie wurden als vergleichende konventionelle Methoden eingesetzt.

Ergebnisse

LC‐OCT hatte die höchste Sensitivität und den höchsten negativen Vorhersagewert aller verwendeten Methoden, dicht gefolgt von PCR und OCT. Die Spezifität und der positive Vorhersagewert der LC‐OCT waren genauso hoch wie bei der KLM, während OCT deutlich schlechter abschnitt. Das Goldstandardverfahren Pilzkultur zeigte die geringste Sensitivität und den niedrigsten negativen Vorhersagewert. Nur PCR und Kultur ermöglichten eine Differenzierung der Pilzspezies.

Schlussfolgerungen

LC‐OCT ermöglicht eine schnelle und nichtinvasive Diagnostik von Onychomykose, mit Vorteilen gegenüber KLM und OCT und ähnlicher diagnostischer Genauigkeit wie die PCR, aber ohne Differenzierung der Pilzarten. Für eine genaue Nageluntersuchung erfordert die LC‐OCT gut geschulte und erfahrene Anwender.

Optimized Ribociclib nanostructured lipid carrier for the amelioration of skin cancer: Inferences from ex-vivo skin permeation and dermatokinetic studies

Current research focuses on explicitly developing and evaluating nanostructured lipidic carriers (NLCs) for the chemotherapeutic drug Ribociclib (RCB) via the topical route to surmount the inherent bioavailability shortcomings. The absolute oral bioavailability has not been determined, but using a physiologically based pharmacokinetic model it was predicted that 65.8 % of the standard dose of RCB (600 mg) would be absorbed mainly in the small intestine. RCB-NLCs were produced using the solvent evaporation method, and Box-Behnken Design (BBD) was employed to optimize composition. The prepared NLCs had an average PS of 79.29 ± 3.53 nm, PDI of 0.242 ± 0.021, and a %EE of 86.07 ± 3.14. The TEM analysis disclosed the spherical form and non-aggregative nature of the NLCs. The outcomes of an in-vitro release investigation presented cumulative drug release of 84.97 ± 3.37 % in 24 h, significantly higher than that from the RCB suspension (RCB-SUS). Ex-vivo skin permeation investigations on rodent (Swiss albino mice) revealed that RCB-NLCs have 1.91 times increases in skin permeability comparable to RCB-SUS. Compared to RCB-SUS, RCB-NLCs were able to penetrate deeper into the epidermis membrane than RCB-SUS as per the findings of confocal microscopy. In dermatokinetic study, higher amount of RCB was maintained in both the layers of mice's skin when treated with RCB-NLCs gel comparable to the RCB-SUS gel preparation. The in-vitro, ex-vivo, CLSM, and dermatokinetics data demonstrated a significant possibility for this novel RCB formulation to be effective against skin cancer.

Optimization, In Vitro and Ex Vivo Assessment of Nanotransferosome Gels Infused with a Methanolic Extract of Solanum xanthocarpum for the Topical Treatment of Psoriasis

The goal of this investigation is to improve the topical delivery of medicine by preparing and maximizing the potential of a nanotransferosome gel infused with Solanum xanthocarpum methanolic extract (SXE) to provide localized and regulated distribution. Thin-film hydration was used to create SXE-infused nanotransferosomes (SXE-NTFs), and a Box-Behnken design was used to improve them. Phospholipon 90G (X1), cholesterol (X2) and sodium cholate (X3) were chosen as the independent variables, and their effects on vesicle size (Y1), polydispersity index (PDI) (Y2) and the percentage of entrapment efficiency (EE) (Y3) were observed both individually and in combination. For the SXE-NTFs, the vesicle size was 146.3 nm, the PDI was 0.2594, the EE was 82.24 ± 2.64%, the drug-loading capacity was 8.367 ± 0.07% and the drug release rate was 78.86 ± 5.24%. Comparing the antioxidant activity to conventional ascorbic acid, it was determined to be 83.51 ± 3.27%. Ex vivo permeation tests revealed that the SXE-NTF gel (82.86 ± 2.38%) considerably outperformed the SXE gel (35.28 ± 1.62%) in terms of permeation. In addition, it seemed from the confocal laser scanning microscopy (CLSM) picture of the Wistar rat's skin that the rhodamine-B-loaded SXE-NTF gel had a higher penetration capability than the control. Dermatokinetic studies showed that the SXE-NTF gel had a better retention capability than the SXE gel. According to the experimental results, the SXE-NTF gel is a promising and successful topical delivery formulation.

Comparison of surface roughness parameters Ra/Sa and Rz/Sz with different measuring devices

OBJECTIVES

The aim of this in-vitro study was to investigate the influence of the measuring devices (mechanical and optical) on the surface values Ra/Sa and Rz/Sz of different materials and machined surfaces.

MATERIAL AND METHODS

Mechanical (contact profilometry (CP): Perthometer S6P, Perthen Mahr, G) and optical (scanning electron microscope (SEM): Phenom, FEI, NL; confocal 3D laser scanning microscope (CLSM): VK-100, Keyence, J) measuring devices were used to determine the surface roughness Ra/Sa and Rz/Sz. Glass-ceramic (Empress, Ivoclar-Vivadent, FL), zirconia (Cercon HT, Dentsply, D), composite (Grandio, Voco, D), denture base material (Palapress, Kulzer, D) and titanium (grade 4) were investigated (n = 10 measurements) after surface finishing: sandblasting (Al2O3; 250 μm), diamond treatment (80 μm; wet), sandblasting (Al2O3; 50 μm), and polishing (grit of 4000; wet; Tegramin-25, Struers, D).

STATISTICS

Shapiro-Wilk, ANOVA, Bonferroni post-hoc tests (α = 0.05).

RESULTS

Surface characteristics Ra/Sa and Rz/Sz, which were detected with mechanical and optical measuring devices on different materials and surface finishing, showed significant (p ≤ 0.001, ANOVA) differences. Significant (p ≤ 0.045, Bonferroni) differences between CP, SEM and CLSM (line; area) were found, mainly for Ra/Sa.

DISCUSSION

The surface roughness on different dental materials and differently machined surfaces were influenced by the individual mechanical and optical measuring devices. Optical methods measure a significantly higher roughness value for all materials and surface finishes.

CLSM-Guided Imaging for Quantifying Endodontic Disinfection

Elimination of microbes in the root canal system is crucial for achieving long-term success in endodontic treatment. Further efforts in study design and standardization are needed in order to improve the validity and comparability of in vitro results on endodontic disinfection procedures, in turn improving clinical outcomes. This study optimizes two models at all steps: tooth selection, pretreatment, inoculation method (by growth or centrifugation), and confocal laser scanning microscopy (CLSM)-guided imaging of LIVE/DEAD-stained specimens. Individual anatomical conditions lead to substantial differences in penetration depth. Sclerosis grading (SCG), a classification system introduced in this study, provides information about the sclerosis status of the dentine and is helpful for careful, specific, and comparable tooth selection in in vitro studies. Sonically activated EDTA for the pretreatment of roots, inoculation of Enterococcus faecalis in an overflow model, 3-4 weeks of incubation, as well as polishing of dentine slices before staining, led to advances in the visualization of bacterial penetration and irrigation depths. In contrast, NaOCl pretreatment negatively affected performance reproducibility and should be avoided in any pretreatment. Nonsclerotized teeth (SCG0) can be used for microbial semilunar-shaped inoculation by centrifugation as a "quick-and-dirty" model for initial orientation. In conclusion, CLSM-guided imaging for quantifying endodontic infection/disinfection is a very powerful method after the fine-tuning of materials and methods.

Automated Segmentation and 3D Reconstruction of Different Membranes from Confocal Z-Stacks

Confocal laser scanning microscopy (CLSM) is an advanced microscopy technique based on fluorescence technology which produces sharp images of a specimen in a single focal plane. The optical sectioning by CLSM allows to have z-stacks which can be further processed into 3D reconstructions. These then provide the option of variable perspectives and additional precise data evaluation on structural and anatomical alterations. Here, we used CLSM to image the thylakoids of cyanobacteria and the endoplasmic reticulum (ER) in moss protonemata as an example. Then, out of the confocal z-stacks, we create 3D constructions of the membranes and their alterations to present a holistic, structural view from different angles.

Structural Studies of Mexican Husk Tomato (Physalis ixocarpa) Fruit Cutin

Green tomato (Physalis ixocarpa) is a specie native to Mexico, and it is known as "tomatillo" or "husk tomato". The fruit contains vitamins, minerals, phenolic compounds, and steroidal lactones, presenting antimicrobial activity and antinarcotic effects. Therefore, it is not only used in traditional Mexican cuisine, but also in traditional medicine to relieve some discomforts such as fever, cough, and amygdalitis. However, it is a perishable fruit whose shelf life is very short. As a part of the peel, cuticle, and epicuticular waxes represent the most important part in plant protection, and the specific composition and structural characterization are significant to know how this protective biopolymer keeps quality characteristics in fresh fruits. P. ixocarpa cutin was obtained by enzymatic treatments (cellulase, hemicellulose, and pectinase) and different concentrations of TFA, and studied through Cross Polarization Magic Angle Spinning Nuclear Magnetic Resonance (CPMAS 13C NMR), Ultra-High Performance Liquid Chromatography coupled to Mass Spectrometry (UHPLC-MS), and was morphologically characterized by Confocal Laser Scanning Microscopy (CLSM) and Scanning Electron Microscopy (SEM). The main constituents identified under the basis of UHPLC-MS analysis were 9,10,18-trihydroxy-octadecanoic acid and 9,10-epoxy-18-hydroxy-octadecanoic acid with 44.7 and 37.5%, respectively. The C16 absence and low occurrence of phenolic compounds, besides the presence of glandular trichomes, which do not allow a continuous layer on the surface of the fruit, could be related to a lower shelf life compared with other common fruits such as tomato (Solanum lycopersicum).

Impact of miconazole nitrate ferrying cationic and anionic nanoemulsion and gels on permeation profiles of across EpiDerm, artificial membrane, and skin: Instrumental evidences

Based on our previous report, the study was extended to investigate the impact of miconazole nitrate (MCN) loaded cationic/anionic nanoemulsions and nanoemulsion gels on permeation behaviour across artificial-membrane, EpiDerm, and rat skin. Nanoemulsions and gels were evaluated for size, charge, viscosity, size-distribution, pH, and percent entrapment efficiency (%EE). In vitro drug diffusion across artificial membrane and EpiDerm were conducted to get diffusion coefficients. Permeation profiles were studied using rat skin to investigate mechanistic insight of formulated mediated permeation followed by CLSM (confocal laser scanning microscopy), SEM (scanning electron microscopy), AFM (atomic force microscopy), and irritation studies. Results showed that MCNE11-Rh (probed cationic nanoemulsion at pH ∼ 7.2) and MNE11-Rh (probed anionic nanoemulsion at pH ∼ 7.2) showed size values of 158 nm and 145 nm, respectively whereas MCNE11-GR (probed cationic nanoemulsion gel at pH ∼ 6.8) and MNE11-GR (probed anionic nanoemulsion gel at pH ∼ 6.8) exhibited size values 257 nm and 243 nm, respectively. The %EE values were found to be as 91.5 % and 89.6 % for MCNE11-Rh and MNE11-Rh, respectively. The gels (∼6000 cP) elicited relatively high viscosity than nanoemulsions (∼3300 - 3500 cP). MCNE11-GR showed the highest values of permeation flux, diffusion rate, diffusion coefficient (D), and permeation coefficient (P) across artificial membrane, EpiDerm, and rat skin which may be attributed to three potential factors (cationic charge, composition, and hydration by the hydrophilic gel) working in tandem. Transepidermal water loss (TEWL) by the MCNE11-GR was maximum (14.4 g/m2h) than control (6.1 g/m2h) indicating augmented interaction of MCNE11-Rh with skin components. Conclusively, cationic nanoemulsion gel was promising carrier for enhanced permeation and the drug access to the dermal region to treat deep seated fungal infections.

Bacillus subtilis NDmed, a model strain for biofilm genetic studies

The Bacillus subtilis strain NDmed was isolated from an endoscope washer-disinfector in a medical environment. NDmed can form complex macrocolonies with highly wrinkled architectural structures on solid medium. In static liquid culture, it produces thick pellicles at the interface with air as well as remarkable highly protruding ''beanstalk-like'' submerged biofilm structures at the solid surface. Since these mucoid submerged structures are hyper-resistant to biocides, NDmed has the ability to protect pathogens embedded in mixed-species biofilms by sheltering them from the action of these agents. Additionally, this non-domesticated and highly biofilm forming strain has the propensity of being genetically manipulated. Due to all these properties, the NDmed strain becomes a valuable model for the study of B. subtilis biofilms. This review focuses on several studies performed with NDmed that have highlighted the sophisticated genetic dynamics at play during B. subtilis biofilm formation. Further studies in project using modern molecular tools of advanced technologies with this strain, will allow to deepen our knowledge on the emerging properties of multicellular bacterial life.

Chitosan Nanoparticles for Enhanced Delivery of Sida cordifolia Extract: Formulation, Optimization and Bioactivity Assessment

In a continuous search for an essential antidiabetic agent, Sida cordifolia hydroalcoholic (SCHA) extract-loaded chitosan nanoparticles (SCHA-CS-NP) were optimized. The Box-Behnken design (BBD Design-Expert software, version 14) with three parameters was used to optimize the nanoparticles after creating them using the ion gelation method. The chitosan and Tween 20 contents and the stirring speed were chosen as the independent variables, and their separate and combined effects on particle size (Y1), polydispersity index (Y2) and entrapment efficiency (Y3) were observed. The optimized formulation showed a particle size of 51 nm, an entrapment efficiency of 84.54% and a polydispersity index of 0.391. Physicochemical characterization, Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), a drug release study, an ex vivo permeation study, and an antioxidant study were performed. Confocal laser scanning microscopy (CLSM) images demonstrated that chitosan nanoparticles loaded with rhodamine B-laden SCHA extract had superior penetration compared to the control (rhodamine B solution). Furthermore, compared to conventional ascorbic acid (IC50 = 45 µg/mL), a superior antioxidant activity was discovered for SCHA-CS-NPs (IC50 = 86.45 ± 2.24 µg/mL), while SCHA-CS-NPs also exhibited strong antidiabetic potential (IC50 = 93.71 ± 1.79 µg/mL) compared to standard acarbose (IC50 = 97.25 ± 1.43 µg/mL). The overall results demonstrated that SCHA-CS-NPs are a promising and efficient formulation for oral delivery.

Wound Dressing Scaffold with High Anti-biofilm Performance Based on Ciprofloxacin-Loaded Chitosan-Hydrolyzed Starch Nanocomposite: In Vitro and In Vivo Study

Today, the search for solutions to reduce wound infection and restore wound receptivity also reduces its side effects which are a difficult problem in medical science research. The greatest options for this purpose are hydrogel dressings since they are compatible with tissue and have an antibacterial effect on wound healing. Chronic wounds represent a significant burden on people and healthcare systems worldwide. Bacteria often enter such skin wounds, causing irritation and complicating the healing process. In addition, bacteria cause infection, which inhibits rejuvenation and the production of collagen. This study is aimed at developing novel chitosan (CS)-hydrolyzed starch nanocomposite (HS/Ch-NC) loaded with ciprofloxacin to enhance its skin retention and wound healing efficacy and anti-biofilm efficacy. Drug-loading on the (HS/Ch-NC) and encapsulation efficiency was 55.2% and 97.2%, respectively. The activity of HS-NC loaded with ciprofloxacin as anti-biofilm activity by 72% and 63% against Enterobacter aerogenes and Pseudomonas aeruginosa, respectively. The obtained (HS/Ch-NC) loaded with ciprofloxacin is a promising candidate for the development of improved bandage materials, as cell viability and proliferation was assessed using an SRB assay with half-maximal inhibitory concentrations (IC50) at 119.1 µg/ml. In vitro scratch wound healing assay revealed significant (p ≤ 0.05) acceleration in wound closure at 24 h enhanced by 56.04% 24-h and 100% 72-h post-exposure to (HS/Ch-NC) loaded ciprofloxacin, compared to the negative control. In vivo skin retention study revealed that (HS/Ch-NC)-loaded ciprofloxacin showed 3.65-fold higher retention, respectively, than ciprofloxacin. Thus, our study assumes that ciprofloxacin-loaded HS-NC is a potential delivery system for enhancing ciprofloxacin skin retention and wound healing activity.

Dynamic interactions between Candida albicans and different streptococcal species in a multispecies oral biofilm

The oral cavity is colonized by a plethora of bacteria, fungi, and archaea, including streptococci of the mitis group (MSG) and the yeast Candida albicans. This study aims to investigate the role of streptococcal species in the development of oral biofilm and the cross-kingdom interactions between some of the members of the commensal MSG and the pathogen yeast C. albicans using a multispecies supragingival biofilm model. A total of nine different in vitro biofilms were grown, quantified with culture analyses, and visually examined with confocal laser scanning microscopy (CLSM). A four-species biofilm without any streptococcal species was used as a basic biofilm. In each subsequent inoculum, one species of MSG was added and afterward combined with Streptococcus mutans. The eight-species biofilm contained all eight strains used in this study. Culture analyses showed that the presence of S. mutans in a four-species biofilm with Streptococcus oralis or S. oralis subsp. tigurinus did not differ significantly in C. albicans colony-forming unit (CFU) counts compared to biofilms without S. mutans. However, compared to other mitis species, Streptococcus gordonii combined with S. mutans resulted in the lowest CFUs of C. albicans. Visual observation by CLSM showed that biofilms containing both S. mutans and one species of MSG seemed to induce the formation of filamentous form of C. albicans. However, when several species of MSG were combined with S. mutans, C. albicans was again found in its yeast form.

In-vitro and ex-vivo antidiabetic, and antioxidant activities of Box-Behnken design optimized Solanum xanthocarpum extract loaded niosomes

One of the most prevalent lifestyle diseases, diabetes mellitus (DM) is brought on by an endocrine issue. DM is frequently accompanied by hyperglycemia, a disease that typically results in an excess of free radicals that stress tissues. The medical community is currently concentrating on creating therapeutic medications with roots in nature to lessen the damage associated with hyperglycemia. Solanum xanthocarpum has a number of medicinal benefits. The investigation aimed to produce and analyze niosomal formulations containing S. xanthocarpum extract (SXE). Niosomes were made by implementing the solvent evaporation process, which was further optimized using Box-Behnken design. Drug release, DPPH assessments, α-amylase inhibition assay, α-glucosidase inhibition assay, and confocal laser scanning microscopy (CLSM) investigation were all performed on the developed formulation (SXE-Ns-Opt). SXE-Ns-Opt displayed a 253.6 nm vesicle size, a PDI of 0.108, 62.4% entrapment efficiency, and 84.01% drug release in 24 h. The rat's intestinal CLSM image indicated that the rhodamine red B-loaded SXE-Ns-Opts had more intestinal penetration than the control. Additionally, the antioxidant effect of the obtained formulation was demonstrated as 89.46% as compared to SXE (78.10%). Additionally, acarbose, SXE, and SXE-Ns-Opt each inhibited the activity of α-amylase by 95.11%, 85.88%, and 89.87%, and also suppressed the enzyme of α-glucosidase by 88.47%, 81.07%, and 85.78%, respectively. To summarise, the establishment of the SXE-Ns-Opt formulation and its characterization demonstrated the legitimacy of the foundation. A promising candidate for the treatment of diabetes mellitus has been shown as in vitro studies, antioxidant against oxidative stress, CLSM of rat's intestine and a high degree of penetration of formulation.

Morphology of Neutrophils during Their Activation and NETosis: Atomic Force Microscopy Study

Confocal microscopy and fluorescence staining of cellular structures are commonly used to study neutrophil activation and NETosis. However, they do not reveal the specific characteristics of the neutrophil membrane surface, its nanostructure, and morphology. The aim of this study was to reveal the topography and nanosurface characteristics of neutrophils during activation and NETosis using atomic force microscopy (AFM). We showed the main stages of neutrophil activation and NETosis, which include control cell spreading, cell fragment formation, fusion of nuclear segments, membrane disruption, release of neutrophil extracellular traps (NETs), and final cell disintegration. Changes in neutrophil membrane nanosurface parameters during activation and NETosis were quantified. It was shown that with increasing activation time there was a decrease in the spectral intensity of the spatial periods. Exposure to the activator A23187 resulted in an increase in the number and average size of cell fragments over time. Exposure to the activators A23187 and PMA (phorbol 12-myristate 13-acetate) caused the same pattern of cell transformation from spherical cells with segmented nuclei to disrupted cells with NET release. A23187 induced NETosis earlier than PMA, but PMA resulted in more cells with NETosis at the end of the specified time interval (180 min). In our study, we used AFM as the main research tool. Confocal laser-scanning microscopy (CLSM) images are provided for identification and detailed analysis of the phenomena studied. In this way, we exploited the advantages of both techniques.

Resin structure impacts two-component protein adsorption and separation in anion exchange chromatography

The influence of the resin structure, on the competitive binding and separation of a two-component protein mixture with anion exchange resins is evaluated using conalbumin and green fluorescent protein as a model system. Two macroporous resins, one with large open pores and one with smaller pores, are compared to a resin with grafted polymers. Investigations include measurements of single and two-component isotherms, batch uptake kinetics and two-component column breakthrough. On both macroporous resins, the weaker binding protein, conalbumin, is displaced by the stronger binding green fluorescent protein. For the large pore resin, this results in a pronounced overshoot and efficient separation by frontal chromatography. The polymer-grafted resin exhibits superior capacity and kinetics for one-component adsorption, but is unable to achieve separation due to strongly hindered counter-diffusion. Intermediate separation efficiency is obtained with the smaller pore resin. Confocal laser scanning microscopy provides a mechanistic explanation of the underlying intra-particle diffusional phenomena revealing whether unhindered counter-diffusion of the displaced protein can occur or not. This study demonstrates that the resin's intra-particle structure and its effects on diffusional transport are crucial for an efficient separation process. The novelty of this work lies in its comprehensive nature which includes examples of the three most commonly used resin structures: a small pore agarose matrix, a large-pore polymeric matrix, and a polymer grafted resin. Comparison of the protein adsorption properties of these materials provides valuable clues about advantages and disadvantages of each for anion exchange chromatography applications.

Mechanistic of Vesicular Ethosomes and Elastic Liposomes on Permeation Profiles of Acyclovir across Artificial Membrane, Human Cultured EpiDerm, and Rat Skin: In Vitro-Ex Vivo Study

Acyclovir (ACV) controls cutaneous herpes, genital herpes, herpes keratitis, varicella zoster, and chickenpox. From previously reported ACV formulations, we continued to explore the permeation behavior of the optimized ACV loaded optimized ethosome (ETHO2R) and elastic liposome (ELP3R) and their respective carbopol gels across artificial membrane, cultured human EpiDerm, and rat skin. Transepidermal water loss (TEWL), scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM), and atomic force microscopy (AFM) were used to investigate the mechanistic perspective of permeation behavior. The size values of reformulated ELP3-R and ETHO2-R were observed as 217 and 128 nm, respectively (close to previous report), whereas their respective gels showed as 231 and 252 nm, respectively. ETHO2R showed high elasticity, %EE, and low vesicle size. These were investigated for the diffusion rate of the drug permeation (3 h) across the artificial membrane, cultured human EpiDerm, and rat skin. ETHO2GR showed the highest permeation flux (78.42 µg/cm2/h), diffusion coefficient (8.24 × 10-5 cm2/h), and permeation coefficient (0.67 × 10-3 cm/h) of ACV across synthetic membrane, whereas diffusion coefficient (2.4 × 10-4 cm2/h) and permeation coefficient (0.8 × 10-3 cm/h) were maximum across EpiDerm for ETHO2GR. ETHO2R suspension showed maximized permeation flux (169.58 µg/cm2/h) and diffusion rate (0.293 mg/cm2/h1/2), suggesting the rapid internalization of vesicles with cultured skin cells at low viscosity. A similar observation was revealed using rat skin, wherein the permeation flux (182.42 µg/cm2/h), permeation coefficient (0.3 × 10-2 cm/h), and diffusion rate (0.315 mg/cm2/h1/2) of ETHO2R were relatively higher than ELP3R and ELP3GR. Relative small size (128 nm), low viscosity, ethanol-mediated ultra-deformability, high drug entrapment (98%), and elasticity (63.2) are associated with ETHO2R to provide remarkable permeation behavior across the three barriers. The value of TEWL for ETHO2R (21.9 g/m2h) was 3.71 times higher than untreated control (5.9 g/m2h), indicating ethanol-mediated maximized surficial skin lipid perturbation at 3 h of application, whereas the respective ETHO2GR-treated rat skin had TEWL value (18.6 g/m2h) slightly lower than ETHO2R due to gel-based hydration into the skin. SEL, CLSM, and AFM provided a mechanistic perspective of ETHO2R and ELP3R-mediated permeation across rat skin and carrier-mediated visualization (skin-vesicle interaction). AFM provided detailed nanoscale surface roughness topographical parameters of treated and untreated rat skin as supportive data to SEM and CLSM. Thus, ethosomes ETHO2R and respective gel assisted maximum permeation of ACV across rat skin and cultured human EpiDerm to control cutaneous herpes infection and herpes keratitis.

Thermomechanical Stress Analysis of Hydrated Vital Gluten with Large Amplitude Oscillatory Shear Rheology

Vital gluten is increasingly researched as a non-food product for biodegradable materials. During processing, the protein network is confronted with increased thermal and mechanical stress, altering the network characteristics. With the prospect of using the protein for materials beyond food, it is important to understand the mechanical properties at various processing temperatures. To achieve this, the study investigates hydrated vital gluten under thermomechanical stress based on large amplitude oscillatory shear (LAOS) rheology. LAOS rheology was conducted at increasing shear strains (0.01-100%), various frequencies (5-20 rad/s) and temperatures of 25, 45, 55, 65, 70 and 85 °C. With elevating temperatures up to 55 °C, the linear viscoelastic moduli decrease, indicating material softening. Then, protein polymerization and the formation of new cross-links due to thermal denaturation cause more network connectivity, resulting in significantly higher elastic moduli. Beyond the linear viscoelastic regime, the strain-stiffening ratio rises disproportionately. This effect becomes even more evident at higher temperatures. Lacking a viscous contribution, the highly elastic but also stiff network shows less mechanical resilience. Additionally, at these elevated temperatures, structural changes during the protein's denaturation and network shrinkage due to water evaporation could be visualized with confocal laser scanning microscopy (CLSM).

Stages of NETosis Development upon Stimulation of Neutrophils with Activators of Different Types

Before NETs are released, the neutrophil undergoes structural changes. First, it flattens, accompanied by a change in cell shape and rearrangement of the cytoskeleton. Then, nuclear swelling begins, which ends with the ejection of NETs into the extracellular space. We used widefield and confocal fluorescence microscopy to register morphological and structural changes in neutrophils during activation and NETosis. Different types of activators were used, such as NOX-dependent PMA and calcium ionophore A23187. The measurements were performed in a series of sequential stages. In the first stage (30 s after addition of activators and immediately after stimulation of neutrophils), the response of neutrophils to A23187 and PMA exposure was studied. Subsequently, the characteristics of neutrophils in different phases of activation were examined over a longer period of time (30, 60, 120, 180, and 240 min). The specific features of NETosis development were analyzed separately. During the first 30 s, neutrophils appeared to be heterogeneous in shape and structure of the actin cytoskeleton. Characteristic cell shapes included 30″ type 1 cells, similar in shape to the control, with F-actin concentrated in the center of the cytoplasm, and 30″ type 2 cells, which had flattened (spread) shapes with increased frontal dimensions and F-actin distributed throughout the cell. Later, the development of nuclear swelling, the corresponding changes in neutrophil membranes, and NET release into the extracellular space were evaluated. The conditions determining the initiation of chromatin ejection and two characteristic types of decondensed chromatin ejection were revealed. The results obtained contribute to a better understanding of the biophysical mechanisms of neutrophil activation and NETosis development.

Antimicrobial, Antibiofilm, and Anticancer Activities of Syzygium aromaticum Essential Oil Nanoemulsion

In the current study, clove oil nanoemulsion (CL-nanoemulsion) and emulsion (CL-emulsion) were prepared through an ecofriendly method. The prepared CL-nanoemulsion and CL-emulsion were characterized using dynamic light scattering (DLS) and a transmission electron microscope (TEM), where results illustrated that CL-nanoemulsion droplets were approximately 32.67 nm in size and spherical in shape, while CL-nanoemulsion droplets were approximately 225.8 nm with a spherical shape. The antibacterial activity of CL-nanoemulsion and CL-emulsion was carried out using a microbroth dilution method. Results revealed that the preferred CL-nanoemulsion had minimal MIC values between 0.31 and 5 mg/mL. The antibiofilm efficacy of CL-nanoemulsion against S. aureus significantly decreased the development of biofilm compared with CL-emulsion. Furthermore, results illustrated that CL-nanoemulsion showed antifungal activity significantly higher than CL-emulsion. Moreover, the prepared CL-nanoemulsion exhibited outstanding antifungal efficiency toward Candida albicans, Cryptococcus neoformans, Aspergillus brasiliensis, A. flavus, and A. fumigatus where MICs were 12.5, 3.12, 0.78, 1.56, and 1.56 mg/mL, respectively. Additionally, the prepared CL-nanoemulsion was analyzed for its antineoplastic effects through a modified MTT assay for evaluating apoptotic and cytotoxic effects using HepG2 and MCF-7 cell lines. MCF-7 breast cancer cells showed the lowest IC50 values (3.4-fold) in CL-nanoemulsion relative to that of CL-emulsion. Thus, CL-nanoemulsion induces apoptosis in breast cancer cells by inducing caspase-8 and -9 activity and suppressing VEGFR-2. In conclusion, the prepared CL-nanoemulsion had antibacterial, antifungal, and antibiofilm as well as anticancer properties, which can be used in different biomedical applications after extensive studies in vivo.

A promising microbial α-amylase production, and purification from Bacillus cereus and its assessment as antibiofilm agent against Pseudomonas aeruginosa pathogen

BACKGROUND AND AIM

The purpose of the current study is to isolate a heavily amylase-producing bacteria of the genus Bacillus from soil samples, optimize the production of the enzyme, purify it, and evaluate its activity against biofilm-producing bacteria. A total of 12 soil samples were collected and screened for promising Bacillus species with good amylolytic activity. Isolation was done by serial dilution and plating technique and amylolytic activity was determined by starch agar plate method. Among the 12 Bacillus isolates recovered from soil samples, 7 showed positive α-amylase production. The best isolate that recorded the greatest amylolytic activity was selected for further studies. This isolate was identified by 16S rRNA sequencing as Bacillus cereus and registered under gene bank accession number OP811897. Furthermore, the α-amylase enzyme was produced by a submerged fermentation technique using best production media and partially purified by ammonium sulfate and chilled ethanol and molecular weight had been determined by SDS-PAGE gel electrophoresis. The production of α-amylase was optimized experimentally by one-factor at a time protocol and statistically by Plackett-Burman design as well as RSM CCD design. Data obtained from OFAT and CCD revealed that α-amylase activities were 1.5- and twofold respectively higher as compared to un-optimized conditions. The most significant factors had been identified and optimized by CCD design.

RESULTS

Among the eleven independent variables tested by PBD, glucose, peptone, (NH4)₂SO4, and Mg SO₄ were the most significant parameters for α-amylase production with an actual yield of 250U/ml. The best physical parameters affecting the enzyme production were incubation time at 35 °C, and pH 5.5 for 48 h. The partially purified enzyme with 60% ammonium sulphate saturation with 1.38- fold purification showed good stability characteristics at a storage temperature of 4 °C and pH up to 8.5 for 21 days. Antibiofilm activity of purified α-amylase was determined against Pseudomonas aeruginosa (ATCC 35659) by spectrophotometric analysis and CLSM microscopic analysis. Results demonstrated biofilm inhibition by 84% of the formed Pseudomonas biofilm using a microtiter plate assay and thickness inhibition activity by 83% with live/Dead cells percentage of 17%/83% using CLSM protocol.

CONCLUSIONS

A highly stable purified α-amylase from B. cereus showed promising antibiofilm activity against one of the clinically important biofilm-forming MDR organisms that could be used as a cost-effective tool in pharmaceutical industries.

The Influence of Fiber on the Mechanical Properties of Controllable Low-Strength Materials

Numerous studies have been conducted on fiber-reinforced concrete; however, comparative investigations specifically focusing on the utilization of fibers in CLSM remain limited. In this study, we conducted a systematic investigation into the mechanical properties of controlled low-strength material (CLSM) by manipulating the length and doping amount of fibers as control variables. The 7-day compressive strength (7d-UCS), 28-day compressive strength (28d-UCS), and 28-day splitting strength of CLSM were employed as indicators to evaluate the material's performance. Based on our comprehensive analysis, the following conclusions were drawn: (1) A positive correlation was observed between fiber length and material strength within the range of 0-6 mm, while conversely, a negative correlation was evident. Similarly, when the fiber doping was within the range of 0-0.3%, a positive correlation was identified between material strength and fiber doping. However, the strength of CLSM decreased when fiber doping exceeded 0.3%. (2) SEM and PCAS analyses provided further confirmation that the incorporation of fibers effectively reduced the porosity of the material by filling internal pores and interacting with hydration products, thereby forming a mesh structure. Overall, this study offers valuable insights into the manipulation of fiber length and doping amount to optimize the mechanical properties of CLSM. The findings have important implications for the practical application of CLSM, particularly in terms of enhancing its strength through fiber incorporation.

The Influence of Various Adhesive Systems and Polishing Methods on Enamel Surface Roughness after Debonding of Orthodontic Brackets: A Three-Dimensional In Vitro Evaluation

A slight alteration of the enamel surface is inevitable upon debonding of orthodontic brackets, adhesive removal, and finishing/polishing. The aim of this in vitro study was to compare two adhesives and three polishing methods by measuring enamel surface roughness using confocal laser scanning microscopy (CLSM). Brackets were bonded on 42 extracted human premolars using Transbond XT (Transbond group) or Fuji Ortho (Fuji group). After debracketing, adhesives were removed with a tungsten carbide bur, and surfaces were polished using Sof-Lex discs, a rotary brush with a prophylactic paste (Depural), or a prophylactic cup with two polishing pastes (n = 7 in each subgroup). Surface roughness (S_a, S_ku, S_q, and S_z) was measured using CLSM and compared before treatment (T₁), after debracketing and adhesive removal (T₂), and after polishing (T₃). The data were statistically analyzed using the Mann-Whitney U and Kruskal-Wallis tests with Bonferroni correction. The time required for adhesive removal was measured and compared using a two-sample t-test. Surface roughness at T₂ increased compared to T₁, but the difference was significant only for the Fuji group (p < 0.01). The time required to remove Transbond XT (94.1 ± 6.8 s) was significantly higher compared to Fuji (72.1 ± 5.9 s, p < 0.0001). Polishing with Sof-Lex discs resulted in lower surface roughness compared to T₁ (p = 0.018). Using Depural and polishing pastes showed no significant difference in surface roughness compared to T₁, except for a significant decrease in S_a and S_q for Transbond (p = 0.043) and in S_ku for Fuji (p = 0.018) after polishing with Depural. In conclusion, the removal of Transbond took significantly longer, but there were fewer residues of composite resin on the enamel surface. Sof-Lex discs decreased enamel roughness, whereas enamel morphology and roughness were similar to the pre-treatment state after polishing with polishing pastes.

First 3-D reconstruction of copulation in Lepidoptera: interaction of genitalia in Tortrix viridana (Tortricidae)

BACKGROUND

The process of copulation in Lepidoptera is understudied and poorly understood from a functional perspective. The purpose of the present paper is to study the interaction of the male and female genitalia of Tortrix viridana Linnaeus, 1758 via three-dimensional models of pairs fixed during copulation. Other techniques (confocal laser scanning microscopy, scanning electron microscopy and histology) were used to clarify the role of the organs involved in the process.

RESULTS

Three-dimensional models based on micro-CT scanned copulating pairs were generated allowing visualisation of the position of the male and female counterparts, spatial changes during copulation, and the skeleto-muscular apparatus involved in the process. The male genitalia and their musculature are simplified in comparison with other lineages of the family, but the opposite is true for the female genitalia. The attachment of the couple is achieved only through flexion of the valvae, clasping the large and sclerotised sternite 7 of the female. The anal cone and socii of the male are in contact with certain parts of the anal papillae and the sterigma of the female. The long tubular vesica is inserted into the narrow posterior part of the ductus bursae. Its eversion is achieved by an increase in haemolymph pressure. A possible mechanism of stimulation of the female via pulsations of the diverticulum of the vesica was discovered. A compressed sclerotised area of the ductus bursae putatively serves as a valve controlling the transfer of ejaculated materials. Copulation progresses through two phases: in the first the vesica and its diverticulum are inflated by haemolymph, and in the second the diverticulum is not inflated, and the vesica is occupied by viscous ejaculated material. The formation of the multilayered spermatophore was observed, and we discovered that sperm is transferred very late in the copulation process.

CONCLUSIONS

Copulation process in Lepidoptera is studied for the first time with three-dimensional reconstructions of couples of Tortrix viridana, used as a model species. The internal genitalia is the scenario of multiple interactions between male and female, but the external remain static. A possible mechanism of stimulation of the female internal copulation organs is proposed.

Spatial organization and proteome of a dual-species cyanobacterial biofilm alter among N2-fixing and non-fixing conditions

Many disciplines have become increasingly interested in cyanobacteria, due to their ability to fix CO₂ while using water and sunlight as electron and energy sources. Further, several species of cyanobacteria are also capable of fixing molecular nitrogen, making them independent of the addition of nitrate or ammonia. Thereby they hold huge potential as sustainable biocatalysts. Here, we look into a dual-species biofilm consisting of filamentous diazotrophic cyanobacteria Tolypothrix sp. PCC 7712 and heterotrophic bacteria Pseudomonas taiwanensis VLB 120 growing in a capillary biofilm reactor. Such systems have been reported to enable high cell densities continuous process operation. By combining confocal laser scanning and helium-ion microscopy with a proteomics approach, we examined these organisms' interactions under two nitrogen-feeding strategies: N₂-fixing and nitrate assimilation. Not only did Pseudomonas facilitate the biofilm formation by forming a carpet layer on the surface area but also did N₂-fixing biofilms show greater attachment to the surface. Pseudomonas proteins related to surface and cell attachments were observed in N₂-fixing biofilms in particular. Furthermore, co-localized biofilm cells displayed a resilient response to extra shear forces induced by segmented media/air flows. This study highlights the role of Pseudomonas in the initial attachment process, as well as the effects of different nitrogen-feeding strategies and operation regimes on biofilm composition and growth.IMPORTANCECyanobacteria are highly interesting microorganisms due to their ability to synthesize sugars from CO₂ while using water and sunlight as electron and energy sources. Further, many species are also capable of utilizing molecular nitrogen, making them independent of artificial fertilizers. In this study, such organisms are cultivated in a technical system, which enables them to attach to the reactor surface, and form three-dimensional structures termed biofilms. Biofilms achieve extraordinarily high cell densities. Furthermore, this growth format allows for continuous processing, both being essential features in biotechnological process development. Understanding biofilm growth and the influence technical settings and media composition have on biofilm maturation and stability are crucial for reaction and reactor design. These findings will help to open up these fascinating organisms for applications as sustainable, resource-efficient industrial workhorses.

Development of the Pseudomonas syringae pv. morsprunorum Biofilm Monitored in Real Time Using Attenuated Total Reflection Fourier Transform Infrared Measurements in a Flow Cell Chamber

Biofilms of sessile Pseudomonas syringae cells formed on top of plant host's leaves or fruits allow surviving harsh environmental conditions (desiccation) and improve their resistance to antibacterial treatments of crops. A better understanding of these biofilms can help minimize their effect on harvests. In the present study, infrared attenuated total reflection spectroscopy coupled with optical and confocal laser scanning microscopy has been applied for the first time to analyze Pseudomonas syringae pathovar morsprunorum biofilm development in real time. The biofilm development was observed within a spectral window 4000-800 cm^-1 under constant flow conditions for 72 h. The kinetics of representative integrated band areas (nucleic acids with polysaccharides at 1141-1006 cm^-1, amino acid side chains with free fatty acids at 1420-1380 cm^-1, proteins at 1580-1490 cm^-1, and lipids with proteins at 2935-2915 cm^-1) were analyzed with regard to the observed biofilm structure and the following P. syringae biofilm developmental stages were attributed: The inoculation phase, washing of weakly attached bacteria closely followed by recolonization of the vacated surface, the restructuration phase, and finally the maturation phase.

Precooking treatments affect the sensory and tensile properties of autoclaved recooked noodles via moisture distribution and protein structure

To improve the quality of autoclaved recooked noodles (ARNs), this study explored the effects of precooking on the sensory and tensile properties of ARNs from the perspectives of changes in protein structure and water distribution. The results showed that the ARNs of two kinds of pretreatments (Boiling 2 min, Boiling 1 min + Steaming 2 min) presented the best sensory quality (average score ≥ 7.50) and high tensile properties (tensile distance ≥ 45.24 mm). After autoclaving and recooking, the proportion of tightly bound water increased by 11.30%-12.52%, resulting in stronger water-solid interaction. The results of laser confocal microscopy (CLSM) proved that a strengthened gluten network (protein percentage area ≥ 40.28%; junction density ≥ 10.96 × 10^-4) appeared. Therefore, appropriate precooking treatment could effectively improve the sensory quality and tensile properties of ARNs by enhancing the tightly bound water ratio and strengthening the gluten network.

Effect of treatment of Fusarium head blight infected barley grains with hop essential oil nanoemulsion on the quality and safety of malted barley

Fusarium mycotoxin contamination of malting barley has been a persistent food safety issue for malting companies. In this study, the effect of hop essential oil (HEO) nanoemulsion on fungal biomass and mycotoxin production during the malting process was evaluated. Furthermore, the localization of fungal hyphae on the surface and inside the tissue of barley and malts was observed. The application of HEO nanoemulsion reduced fungal biomass and deoxynivalenol (DON) contents at each stage of the malting process as compared to control. During malting process, the fungal hyphae on kernel surfaces was reduced appreciably after steeping. However, the increment of hyphae was observed between the husk and testa layer of barley after germination than raw barley grains. In addition to its antifungal activity, the antioxidant activity of HEO in the treated malts suppressed the formation of aldehydes. This study lays the foundation for the utilization of HEO in the malting industry.

Application of loofah and insects in a bio-trickling filter to relieve clogging

Bio-trickling filters (BTFs) use an inert filler to purify pollutants making them prone to clogging due to bacterial accumulation. To investigate the performance of a non-inert filler in BTF and its cooperation with insects to relieve clogging, a vertical BTF was constructed with a loofah/Pall ring/polydimethylsiloxane composite filler and selected bacteria to purify toluene. The BTF was started up within 17 d and restarted within 3 d after starvation for 12-16 d. Its average removal efficiency was >90% at steady state. The maximum elimination capacity of 86.4 g·(m³·h)^-1 was obtained at a volume capacity of 96.2 g·(m³·h)^-1. The introduction of holometabolous insects (Clogmia albipunctata) rapidly removed the biofilm and accelerated the degradation of the loofah, which alleviated clogging. Furthermore, confocal laser scanning microscope (CLSM) observations showed that the biofilm polysaccharides were difficult to remove, while lipids were readily lost. Analysis of microbial diversity over time and space revealed that the dominant bacterium, Comamonas, was replaced by diverse microflora with no obvious dominant genus. Insect introduction and loofah migration had little effect on the evolution of microflora. This study provides a promising approach to operating BTFs with less clogging.

Antimicrobial Efficacy of Different Irrigant Solutions Using a Novel Biofilm Model: An In Vitro Confocal Laser Scanning Microscopy Experiment

AIM

To determine the ability of different irrigation solutions to biomechanically remove Enterococcus faecalis biofilm from a novel artificial root canal model during chemomechanical preparation.

METHODS

High resolution micro-computer-tomography scans of a mandibular molar's mesial root were used to produce 50 identical 3D-printed resin root canal models. These were cultured with E.faecalis over seven days to generate biofilm and subjected to chemomechanical preparation using: saline; 17% ethylenediaminetetraacetic acid (EDTA) or 2% sodium hypochlorite (NaOCl) alongside positive/negative controls (n = 10). Canals were prepared to 40/.06 taper, with 1 mL irrigation between instruments, followed by 5 mL penultimate rinse, 30 s ultrasonic activation and 5 mL final rinse. Residual biofilm volume (pixels) was determined following immunofluorescent staining and confocal-laser-scanning-microscopy imaging. Statistical comparisons were made using Kruskal-Wallis with post-hoc Dunn's tests (α ⟨0.05).

RESULTS

In all canal thirds, the greatest biofilm removal was observed with NaOCl, followed by EDTA and saline. The latter had significantly higher E.faecalis counts than NaOCl and EDTA (P ⟨0.01). However, no statistical differences were found between EDTA and NaOCl or saline and positive controls (P ⟩0.05).

CONCLUSIONS

Within limitations of this model, 17% EDTA was found to be as effective as 2% NaOCl at eradicating E.faecalis biofilm following chemomechanical preparation. Further investigations with multi-species biofilms are encouraged.

Assessment of Spindle Shape Control by Spindle Poleward Flux Measurements and FRAP Bulk Analysis

In plants, the segregation of genetic material is achieved by an acentrosomal, mitotic spindle. This macromolecular machinery consists of different microtubule subpopulations and interacting proteins. The majority of what we know about the assembly and shape control of the mitotic spindle arose from vertebrate model systems. The dynamic properties of the individual tubulin polymers are crucial for the accurate assembly of the spindle array and are modulated by microtubule-associated motor and non-motor proteins. The mitotic spindle relies on a phenomenon called poleward microtubule flux that is critical to establish spindle shape, chromosome alignment, and segregation. This flux is under control of the non-motor microtubule-associated proteins and force-generating motors. Despite the large number of (plant-specific) kinesin motor proteins expressed during mitosis, their mitotic roles remain largely elusive. Moreover, reports on mitotic spindle formation and shape control in higher plants are scarce. In this chapter, an overview of the basic principles and methods concerning live imaging of prometa- and metaphase spindles and the analysis of spindle microtubule flux using fluorescence recovery after photobleaching is provided.

Application Prospects of FTIR Spectroscopy and CLSM to Monitor the Drugs Interaction with Bacteria Cells Localized in Macrophages for Diagnosis and Treatment Control of Respiratory Diseases

Visualization of the interaction of drugs with biological cells creates new approaches to improving the bioavailability, selectivity, and effectiveness of drugs. The use of CLSM and FTIR spectroscopy to study the interactions of antibacterial drugs with latent bacterial cells localized in macrophages create prospects to solve the problems of multidrug resistance (MDR) and severe cases. Here, the mechanism of rifampicin penetration into E. coli bacterial cells was studied by tracking the changes in the characteristic peaks of cell wall components and intracellular proteins. However, the effectiveness of the drug is determined not only by penetration, but also by efflux of the drugs molecules from the bacterial cells. Here, the efflux effect was studied and visualized using FTIR spectroscopy, as well as CLSM imaging. We have shown that because of efflux inhibition, eugenol acting as an adjuvant for rifampicin showed a significant (more than three times) increase in the antibiotic penetration and the maintenance of its intracellular concentration in E. coli (up to 72 h in a concentration of more than 2 μg/mL). In addition, optical methods have been applied to study the systems containing bacteria localized inside of macrophages (model of the latent form), where the availability of bacteria for antibiotics is reduced. Polyethylenimine grafted with cyclodextrin carrying trimannoside vector molecules was developed as a drug delivery system for macrophages. Such ligands were absorbed by CD206+ macrophages by 60-70% versus 10-15% for ligands with a non-specific galactose label. Owing to presence of ligands with trimannoside vectors, the increase in antibiotic concentration inside macrophages, and thus, its accumulation into dormant bacteria, is observed. In the future, the developed FTIR+CLSM techniques would be applicable for the diagnosis of bacterial infections and the adjustment of therapy strategies.

Microstructure Analysis and Mechanical Properties of Backfill Material Using Stone Sludge

In this study, the optimum mixing ratio for backfill was determined by analyzing the mechanical properties and microstructure of controlled low-strength material (CLSM)-the backfill material for road excavation and restoration-using the total amount of stone sludge generated during aggregate production, including analysis of the flow and material separation resistance by compounding factors. A small-scale field evaluation was conducted using the derived optimal mixing ratio. A comprehensive analysis of the mechanical properties was based on the relevant standards and specifications, and a microstructure analysis indicated that the optimal mixing ratio of CLSM containing stone sludge was 350% W/B. A field applicability evaluation indicated that the flow was 230 mm, and the initial and re-excavation properties were 0.75 and 1.15 MPa, respectively, which met ASTM standards. Monitoring for approximately 5 months revealed that there was no ground subsidence caused by traffic, and it was confirmed that re-excavation with equipment was possible. After re-excavation, the filling properties of CLSM using stone sludge and the pipe periphery were checked, and it was found that no significant filling and pipe damage had occurred.

Functional Characterization of a Bacillus-Derived Novel Broad-Spectrum Antifungal Lipopeptide Variant against Candida tropicalis and Candida auris and Unravelling Its Mode of Action

Limited treatment options, recalcitrance, and resistance to existing therapeutics encourage the discovery of novel antifungal leads for alternative therapeutics. Antifungal lipopeptides have emerged as potential candidates for developing new and alternative antifungal therapies. In our previous studies, we isolated and identified the lipopeptide variant AF4 and purified it to homogeneity via chromatography from the cell-free supernatant of Bacillus subtilis. AF4 was found to have broad-spectrum antifungal activity against more than 110 fungal isolates. In this study, we found that clinical isolates of Candida tropicalis and Candida auris exposed to AF4 exhibited low MICs of 4 to 8 mg/L. Time-kill assays indicated the in vitro pharmacodynamic potential of AF4. Biocompatibility assays demonstrated ~75% cell viability at 8 mg/L of AF4, indicating the lipopeptide's minimally cytotoxic nature. In lipopeptide-treated C. tropicalis and C. auris cells, scanning electron microscopy revealed damage to the cell surface, while confocal microscopy with acridine orange(AO)/propidium iodide (PI) and FUN-1 indicated permeabilization of the cell membrane, and DNA damage upon DAPI (4',6-diamidino-2-phenylindole) staining. These observations were corroborated using flow cytometry (FC) in which propidium iodide, 2',7'-dichlorodihydrofluorescein diacetate (DCFH-DA), and rhodamine 123 (Rh123) staining of cells treated with AF4 revealed loss of membrane integrity, increased reactive oxygen species (ROS) production, and mitochondrial membrane dysfunction, respectively. Membrane perturbation was also observed in the 1,6-diphenyl-1,3,5-hexatriene (DPH) fluorescence study and the interaction with ergosterol was observed by an ergosterol binding assay. Decreased membrane dipole potential also indicated the probable binding of lipopeptide to the cell membrane. Collectively, these findings describe the mode of action of AF4 against fungal isolates by membrane disruption and ROS generation, demonstrating its antifungal potency. IMPORTANCE C. tropicalis is a major concern for candidiasis in India and C. auris has emerged as a resistant yeast causing difficult-to-treat infections. Currently, amphotericin B (AMB) and 5-flucytosine (5-FC) are the main therapeutics for systemic fungal infections; however, the nephrotoxicity of AMB and resistance to 5-FC is a serious concern. Antifungal lead molecules with low adverse effects are the need of the hour. In this study, we briefly describe the antifungal potential of the AF4 lipopeptide and its mode of action using microscopy, flow cytometry, and fluorescence-based assays. Our investigation reveals the basic mode of action of the investigated lipopeptide. This lipopeptide with broad-spectrum antifungal potency is apparently membrane-active, and there is a smaller chance that organisms exposed to such a compound will develop drug resistance. It could potentially act as a lead molecule for the development of an alternative antifungal agent to combat candidiasis.

Preparation of controlled low-strength materials from alkali-excited red mud-slag-iron tailings sand and a study of the reaction mechanism

To address the low utilization of fines in iron tailings sand (IOTs), a controlled low-strength material (CLSM) was prepared from a combination of fine IOTs and red mud (RM) slag. The 7-day unconfined compressive strength (7-d UCS), slump and cost were used as evaluation indicators, and 16 sets of tests were designed with the Box-Behnken design (BBD) response surface method. X-ray diffraction (XRD), Fourier transform infrared (FTIR), and scanning electron microscopy (SEM)-energy dispersive spectroscopy (EDS) were used to study the microscopic morphology and reaction mechanism of the CLSM samples made with the optimal ratios. The results show that the best matching ratio for the alkali-activated RM-slag-IOTs CLSM was a sand ratio of 0.797, an NaOH dose of 3.667% and a mass concentration of 80.657%, and the 7d-UCS, slump and cost indicators verified the feasibility of applying the CLSM to the base course of pavement. Alkali activation of the CLSM also showed that the RM-slag cementation system produced new substances. Internal calcium-silicate-hydrogel (C-S-H) and calcium-aluminosilicate-hydrogel (C-A-S-H) agglomerates were the main sources of strength, and hydration products were interwoven to form a dense structure with crystals as the framework and gels as fillers.

Complementation of an Eisosomal Yeast pil1 Mutant and Characteristics of Eisosomal Distribution in Hyphae of Neurospora crassa Germinating from Two Different Spore Types

Eisosomes are plasma-membrane-associated protein complexes of fungi and algae involved in various cellular processes. The eisosome composition of the budding yeast is well described, but there is a limited number of studies only about eisosomes in filamentous fungi. In our study, we examined the Neurospora crassa LSP-1 protein (NcLSP1). By complementing a Saccharomyces cerevisiae Δpil1 mutant strain with nclsp1, we show the functional homology of the NcLSP1 to yeast PIL1 rather than to yeast LSP1 and hereby confirm that the NcLSP1 is an eisosomal core protein and suitable eisosomal marker. The subsequent cloning and expression of the nclsp1::trfp reporter gene construct in N. crassa allowed for a systematical investigation of the characteristics of eisosome formation and distribution in different developmental stages. In N. crassa, the hyphae germinating from sexual and asexual spores are morphologically identical and have been historically recognized as the same type of cells. Here, we demonstrate the structural differences on the cellular level between the hyphae germinating from sexual and asexual spores.

A novel approach to extract, purify, and fractionate microplastics from environmental matrices by isopycnic ultracentrifugation

The increasing accumulation of microplastics (MP) in the environment is considered one of the most important environmental challenges of our times. Reliable extraction and detection methods for MP in environmental samples are essential for determining the extent of pollution and assessing ecological risks. However, extraction of MP from complex environmental matrices such as soil remains technically challenging. Today, density-based extractions with saturated salt solutions are widely applied. Nevertheless, current methods do not allow for the fractionation of different MP particle types according to their specific polymer densities. Here, we present a novel isopycnic ultracentrifugation approach for the simultaneous extraction and fractionation of MP mixtures based on the particle-specific buoyant densities. In this proof-of-concept study, diffusion-based density gradients were prepared using caesium chloride media, covering a density range between 1.1 and 1.5 g mL^-1_, sufficient to resolve many common polymer densities. We selected MP particles with a low (polyamide; PA66), medium (polybutylene adipate terephthalate; PBAT), and high (polyethylene terephthalate; PET) density to validate separation performance. Both pristine and soil-incubated MP mixtures showed clear banding patterns at expected buoyant densities after isopycnic separation. μFTIR imaging of subsamples collected from resolved MP fractions showed a polymer-specific separation of ≥87.6 %. In addition, the quantitative recovery of MP particles from soil was between 86 and 99 %. The potential of isopycnic ultracentrifugation to preserve MP-associated biofilms was also assessed. Soil-incubated MP particles were inspected by confocal laser scanning microscopy before and after isopycnic separation, indicating a preservation of bioorganic structures. Hence, isopycnic ultracentrifugation offers a powerful novel approach for a polymer-specific extraction and resolution of MP particles with a wide potential for applications in MP research.

Physical and chemical properties, structural characterization and nutritional analysis of kefir yoghurt

Scanning electron microscopy (SEM), Confocal laser scanning microscopy (CLSM) and low field nuclear magnetic resonance (LF-NMR) were used to analyse the relationship between the chemical, texture, rheology, microstructure and water distribution of kefir (yeast, acetic acid bacteria and Lactobacillus plantarum) yoghurt fermented by mixed bacteria and L. plantarum L₁ fermented yoghurt. This work was conducted to prepare a real champagne yoghurt and explore the difference between it and ordinary yoghurt. The nutritional evaluation of the two treatment groups was carried out by amino acid analysis, and the volatile flavour substances of the two treatment groups were detected by solid phase microextraction (SPME)-gas chromatograph (GC)-mass spectrometry (MS). Results showed that the addition of acetic acid bacteria and yeast increased the water content of kefir, resulting in a decrease in its water-holding rate. Moreover, the increase in acidity weakened the connection between the protein networks, the flocculent protein structure was not more densely stacked than the L₁ group, and the internal bonds were unstable. The rheological results showed that the apparent viscosity decreased faster with the increase in shear force. The CLSM and LF-NMR showed that the hydration and degree of freedom of kefir yoghurt protein decreased, resulting in an increased protein network density. The SEM showed that the cross-linking between kefir casein clusters was considerably tight to form small chains, the pore distribution was uneven, and a weak cheese structure was formed. In addition, the volatile flavour substances in the kefir group increased the phenylethyl alcohol, isobutanol, and isoamyl alcohol compared with those in the L₁ group, with a slight refreshing taste brought by alcohol and special soft malt alcohol aroma and rose aroma not found in ordinary yoghurt, which was more in line with the characteristics and taste of traditional kefir champagne yoghurt. Graphical Abstract.

Microwave-assisted and chemically tailored chlorogenic acid-functionalized silver nanoparticles of Citrus sinensis in gel matrix aiding QbD design for the treatment of acne

BACKGROUND

Numerous studies have shown that various products of Citrus sinensis, for example, crude extracts, essential oil, and purified components, possess anti-acne properties. However, the development of chlorogenic acid-functionalized silver nanoparticles of C. sinensis in gel matrix aiding QbD design has not been evaluated for acne treatment.

AIM

In this study, we have developed chlorogenic acid-functionalized silver nanoparticles of C. sinensis in a gel matrix employing a QbD approach for acne treatment.

MATERIAL AND METHOD

Citrus sinensis extract-loaded silver nanoparticles were functionalized with chlorogenic acid, which acted as a bio-reducing agent and further improved anti-acne properties. The developed formulation was optimized via Box-Behnken Design. The formulation morphology was evaluated by transmission electron microscopy (TEM). The release profile of C. sinensis extract formulation was assessed by an in vitro release study and confocal laser scanning microscopy (CLSM). Moreover, the characterization study of the gel was performed that included an evaluation of the extrudability and spreadability of the developed gel. Furthermore, the anti-oxidant efficacy of AgN-CA formulation was validated using the DPPH test.

RESULTS

The results showed a particle size of 71.78 nm, a polydispersity index of 0.297, a zeta potential of -36.12 mV, and an entrapment efficiency of 79.42% ± 6.79%. The results also indicated a uniform particle size. The release profile of C. sinensis extract revealed that 73.95% of the drug was released, whereas CLSM pictures of mice skin evidently demonstrated that the rhodamine B-treated AgN-CA gel penetrated much more extensively in comparison to the control. Furthermore, the anti-oxidant efficacy of AgN-CA formulation was validated using the DPPH test. Moreover, the characterization study of the developed gel, including its extrudability and spreadability, was found to be 16.02 ± 3.21 g and 30.73 ± 5.94 g cm/s, respectively. Also, texture analysis findings revealed that AgN-CA gel had firmness, consistency, cohesiveness, and viscosity index of 159.69 g, 634.95 g s, -116.33 g, and -501.80 g s, respectively, indicating that the AgN-CA gel was stable.

CONCLUSION

The current study showed that AgN-CA is an effective drug carrier system for the topical administration of C. sinensis extract for the treatment of acne.

Phyto-interactive impact of green synthesized iron oxide nanoparticles and Rhizobium pusense on morpho-physiological and yield components of greengram

The iron oxide nanoparticles (IONPs) prepared by green synthesis method using Syzigium cumini leaf extract was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The XRD confirmed the crystalline structure of green synthesized NPs measuring around 33 nm while SEM revealed its nearly spherical shape. Rhizobium species recovered from greengram nodules, identified by 16s rRNA gene sequencing as Rhizobium pusense produced 30% more exopolysaccharides (EPS) in basal medium treated with 1000 μg IONPs/ml. Compositional variation in EPS was observed by Fourier-transform infrared spectroscopy (FTIR). There was no reduction in rhizobial viability and no damage to bacterial membrane was observed under SEM and confocal laser scanning microscopy (CLSM), respectively. Effects of IONPs and R. pusense, used alone and in combination on the growth and development of greengram plants varied considerably. Plants grown with IONPs and R. pusence, used alone and in combination, showed a significant increase in seed germination rate, length and dry biomass of plant organs and seed components compared to controls. The IONPs in the presence of rhizobial strain further increased seed germination, plant growth, seed protein and pigments. Greater protein content (442 mg/g) was observed in seeds at 250 mg/kg of IONPs compared to control. Plants raised with mixture of IONPs plus R. pusense had maximum chlorophyll content (39.2 mg/g FW) while proline content decreased by 53% relative to controls. This study confirms that the green synthesis of IONPs from S. cumini leaf possess useful plant growth promoting effects and could be developed as a nano-biofertilizer for optimizing legume production.

Cell Type-Specific Pherophorins of Volvox carteri Reveal Interplay of Both Cell Types in ECM Biosynthesis

The spheroidal green algae Volvox carteri serves as a model system to investigate the formation of a complex, multifunctional extracellular matrix (ECM) in a relatively simple, multicellular organism with cell differentiation. The V. carteri ECM is mainly composed of hydroxyproline-rich glycoproteins (HRGPs) and there are diverse region-specific, anatomically distinct structures in the ECM. One large protein family with importance for ECM biosynthesis stands out: the pherophorins. The few pherophorins previously extracted from the ECM and characterized, were specifically expressed by somatic cells. However, the localization and function of most pherophorins is unknown. Here, we provide a phylogenetic analysis of 153 pherophorins of V. carteri and its unicellular relative Chlamydomonas reinhardtii. Our analysis of cell type-specific mRNA expression of pherophorins in V. carteri revealed that, contrary to previous assumptions, only about half (52%) of the 102 investigated pherophorin-related genes show stronger expression in somatic cells, whereas about one-third (34%) of the genes show significant higher expression in reproductive cells (gonidia). We fused two pherophorin genes that are expressed by different cell types to yfp, stably expressed them in Volvox and studied the tagged proteins by live-cell imaging. In contrast to earlier biochemical approaches, this genetic approach also allows the in vivo analysis of non-extractable, covalently cross-linked ECM proteins. We demonstrate that the soma-specific pherophorin SSG185 is localized in the outermost ECM structures of the spheroid, the boundary zone and at the flagellar hillocks. SSG185:YFP is detectable as early as 1.5 h after completion of embryogenesis. It is then present for the rest of the life cycle. The gonidia-specific pherophorin PhG is localized in the gonidial cellular zone 1 ("gonidial vesicle") suggesting its involvement in the protection of gonidia and developing embryos until hatching. Even if somatic cells produce the main portion of the ECM of the spheroids, ECM components produced by gonidia are also required to cooperatively assemble the total ECM. Our results provide insights into the evolution of the pherophorin protein family and convey a more detailed picture of Volvox ECM synthesis.

Impact of carbendazim on cellular growth, defence system and plant growth promoting traits of Priestia megaterium ANCB-12 isolated from sugarcane rhizosphere

Agrochemicals are consistently used in agricultural practices to protect plants from pathogens and ensure high crop production. However, their overconsumption and irregular use cause adverse impacts on soil flora and non-target beneficial microorganisms, ultimately causing a hazard to the ecosystem. Taking this into account, the present study was conducted to determine the high dosage of fungicide (carbendazim: CBZM) effects on the rhizobacteria survival, plant growth promoting trait and reactive oxygen species (ROS) scavenging antioxidant enzyme system. Thus, a multifarious plant growth promoting rhizobacteria (PGPR) isolate, ANCB-12, was obtained from the sugarcane rhizosphere through an enrichment technique. The taxonomic position of the isolated rhizobacteria was confirmed through 16S rRNA gene sequencing analysis as Priestia megaterium ANCB-12 (accession no. ON878101). Results showed that increasing concentrations of fungicide showed adverse effects on rhizobacterial cell growth and survival. In addition, cell visualization under a confocal laser scanning microscope (CLSM) revealed more oxidative stress damage in the form of ROS generation and cell membrane permeability. Furthermore, the increasing dose of CBZM gradually decreased the plant growth promoting activities of the rhizobacteria ANCB-12. For example, CBZM at a maximum 3,000 μg/ml concentration decreases the indole acetic acid (IAA) production by 91.6%, ACC deaminase by 92.3%, and siderophore production by 94.1%, respectively. Similarly, higher dose of fungicide enhanced the ROS toxicity by significantly (p < 0.05) modulating the stress-related antioxidant enzymatic biomarkers in P. megaterium ANCB-12. At a maximum 3,000 μg/ml CBZM concentration, the activity of superoxide dismutase (SOD) declined by 82.3%, catalase (CAT) by 61.4%, glutathione peroxidase (GPX) by 76.1%, and glutathione reductase (GR) by 84.8%, respectively. The results of this study showed that higher doses of the fungicide carbendazim are toxic to the cells of plant-beneficial rhizobacteria. This suggests that a recommended dose of fungicide should be made to lessen its harmful effects.

A Feasibility Study for Immediate Histological Assessment of Various Skin Biopsies Using Ex Vivo Confocal Laser Scanning Microscopy

BACKGROUND

Digitally stained ex vivo confocal laser scanning microscopy (CLSM) scans are a possible alternative to formalin-fixed and paraffin-embedded (FFPE) and hematoxylin-eosin (H&E) stained slides. This study explores the diagnostic accuracy of digitally-stained CLSM scans in comparison to H&E-stained slides in various dermatologic diseases in a real-life setting.

METHODS

Samples of patients out of one selected dermatologic office were primarily scanned via CLSM; a diagnosis was made afterwards using FFPE- and H&E-stained slides by two experienced dermatopathologists. Primary outcomes were sensitivity and specificity of diagnosis in digitally stained CLSM scans in three separate diagnostic groups.

RESULTS

CLSM evaluation of epithelial tumors (n = 132) demonstrated a sensitivity of 64.3%/83.9% and a specificity of 84.2%/71.1%. Diagnosis of melanocytic tumors (n = 86) showed a sensitivity of 19.1%/85.1% and a specificity of 96.3%/66.7%. In the diagnosis of other tumors/cysts and inflammatory dermatoses (n = 42), a sensitivity of 96.4%/96.8% and a specificity of 57.1%/45.5% was reached.

CONCLUSIONS

This study shows the possibilities and limitations of a broad use of CLSM. Because of a partly low diagnostic accuracy, such an application does not seem to be recommendable at present for every indication.

Amyloid adhesin production in activated sludge is enhanced in lab-scale sequencing batch reactors: Feeding regime impacts microbial community and amyloid distribution

Amyloid adhesins are β-sheet-rich extracellular proteins thought to contribute to bioflocculation. They are present in activated sludge to varying extent. However, it remains unclear which operational conditions promote their production. To this end, the abundance and distribution of amyloids and their potential producers were monitored in two lab-scale reactors operated in sequencing batch mode with an unaerated and aerated reaction phase. Various feeding regimes ranging from feast-famine to nearly continuous feeding were applied. Thioflavin T staining revealed more amyloids in the lab-scale reactors during all operational stages compared to the full-scale industrial and municipal inocula. Furthermore, the feeding regime impacted the distribution of produced amyloids from dense clusters during feast-famine conditions towards a dispersed distribution during nearly continuous feeding. This dispersed presence did not negatively impact the bioflocculation (towards average floc size and shear sensitivity). 16S rRNA sequencing detected several known EPS and amyloid producers. More continuous and, hence, partially aerobic feeding promoted the relative abundance of denitrifiers. Sequential Thioflavin T staining and fluorescence in situ hybridization identified Zoogloea and Ca. Competibacter as potential amyloid producers under the applied conditions. This experiment confirms that amyloid producers need to be triggered for production and that the feeding regime impacts the microbial community composition, which in turn influences the amyloid production and distribution.

Material gradients in gastropod radulae and their biomechanical significance: a combined approach on the paludomid Lavigeria grandis

The radula, a chitinous membrane spiked with teeth, is the molluscan autapomorphy for the gathering and processing of food. The teeth, as actual interfaces between the organism and the ingesta, act as load transmitting regions and have to withstand high stresses during foraging — without structural failure or high degrees of wear. Mechanisms contributing to this were studied previously in paludomid gastropods from Lake Tanganyika. For some species, gradients in hardness and Young’s modulus along the teeth were detected, enabling the bending and relying of teeth onto the next row, distributing the stresses more equally. The here presented study on one of them — Lavigeria grandis — aims at shedding light on the origin of these functional gradients. The mechanical properties were identified by nanoindentation technique and compared to the elemental composition, determined by elemental dispersive X-ray spectroscopy (EDX, EDS). This was done for the complete radular (mature and immature tooth rows), resulting in overall 236 EDX and 700 nanoindentation measurements. Even though teeth showed regional differences in elemental composition, we could not correlate the mechanical gradients with the elemental proportions. By applying confocal laser scanning microscopy (CLSM), we were finally able to relate the mechanical properties with the degree of tanning. CLSM is a common technique used on arthropod cuticle, but was never applied on radular teeth before. In general, we found that nanoindentation and CLSM techniques complement one another, as for example, CLSM is capable of revealing heterogeneities in material or micro-gradients, which leads to a better understanding of the functionalities of biological materials and structures.

Green Synthesis of Silver Nanoparticles from Camellia sinensis and Its Antimicrobial and Antibiofilm Effect against Clinical Isolates

The green synthesis method of was used for the synthesis of silver nanoparticles using Camellia sinensis (green tea). The Camellia sinensis silver nanoparticles (CS-AgNPs) were characterized using different techniques, including UV-Vis (ultra violet-visible), SEM (scanning electron microscopy), TEM (transmission electron microscopy), and XRD (X-ray diffraction). The average size of the CS-AgNPs was 52 nm, according to TEM. The CS-AgNPs showed excellent antibacterial and antifungal activity. The MIC (minimum inhibitory concentration) against bacterial isolates varied from 31.25 to 62.5 µg/mL, whereas for fungal isolates, the MIC varied from 125 to 250 µg/mL. The presence of a zone in the well diffusion assay showed the antimicrobial nature of CS-AgNPs. Further, CLSM (confocal laser scanning microscopy) showed that CS-AgNPs possess antibiofilm activity. The interaction of CS-AgNPs with the Candidal cells was analyzed using TEM, and it was revealed that CS-AgNPs entered the cell and disrupted the cell machinery.

Architectural Features and Resistance to Food-Grade Disinfectants in Listeria monocytogenes-Pseudomonas spp. Dual-Species Biofilms

Listeria monocytogenes is considered a foodborne pathogen of serious concern capable of forming multispecies biofilms with other bacterial species, such as Pseudomonas spp., adhered onto stainless steel (SS) surfaces. In an attempt to link the biofilms’ morphology and resistance to biocides, dual-species biofilms of L. monocytogenes, in co-culture with either Pseudomonas aeruginosa, Pseudomonas fluorescens, or Pseudomonas putida, were assayed to ascertain their morphological characteristics and resistance toward benzalkonium chloride (BAC) and neutral electrolyzed water (NEW). Epifluorescence microscopy analysis revealed that each dual-species biofilm was distributed differently over the SS surface and that these differences were attributable to the presence of Pseudomonas spp. Confocal laser scanning microscopy (CLSM) assays demonstrated that despite these differences in distribution, all biofilms had similar maximum thicknesses. Along with this, colocalization analyses showed a strong trend of L. monocytogenes to share location within the biofilm with all Pseudomonas assayed whilst the latter distributed throughout the surface independently of the presence of L. monocytogenes, a fact that was especially evident in those biofilms in which cell clusters were present. Finally, a modified Gompertz equation was used to fit biofilms’ BAC and NEW dose-response data. Outcomes demonstrated that L. monocytogenes was less susceptible to BAC when co-cultured with P. aeruginosa or P. fluorescens, whereas susceptibility to NEW was reduced in all three dual-species biofilms, which can be attributable to both the mechanism of action of the biocide and the architectural features of each biofilm. Therefore, the results herein provided can be used to optimize already existing and develop novel target-specific sanitation treatments based on the mechanism of action of the biocide and the biofilms’ species composition and structure.

Larval morphology and temperature-dependent development models of Fannia pusio (Wiedemann): a forensic indicator with expanding distribution

Fannia pusio (Wiedemann) is originally from tropical and subtropical regions of the Americas, where it has repeatedly been collected from both animal carrion and human cadavers. This species is expanding its distributional range, and it has been introduced to Africa, Asia, Australia, Oceania, and Europe. Newly introduced species may be confused with native species of local arthropod necrophagous assemblages, which from a forensic entomology perspective may impact the accuracy of post-mortem interval (PMI) estimations based on insect evidence. In this work we aim to raise awareness among forensic entomologists of the potential benefits and risks associated with the expanding range of F. pusio. Morphology of all larval instars is documented with a combination of light, confocal laser scanning and scanning electron microscopy. Characters allowing identification from other forensically important Fanniidae are listed. Thermal requirements for the development of immature stages of F. pusio were examined under nine ambient temperatures. Models describing changes in larval body length over time were produced for eight different temperatures. The thermal summation constant (k) and developmental zero (T_min) were calculated for six developmental events: hatching, first ecdysis, second ecdysis, wandering, pupariation, and eclosion.

The architecture and metabolic traits of monospecific photosynthetic biofilms studied in a custom flow-through system

Microalgae biofilms have great ecological importance and high biotechnological potential. Nevertheless, an in-depth and combined structural (i.e., the architecture of the biofilm) and physiological characterization of microalgae biofilms is still missing. An approach able to provide the same time physiological and structural information during biofilm growth would be of paramount importance to understand these complex biological systems and to optimize their productivity. In this study, monospecific biofilms of a diatom and a green alga were grown under dynamic conditions in custom flow cells represented by UV/Vis spectroscopic cuvettes. Such flow cells were conceived to characterize the biofilms by several techniques mostly in situ and in a nondestructive way. Physiological traits were obtained by measuring variable chlorophyll a fluorescence by pulse amplitude modulated fluorometry and by scanning the biofilms in a spectrometer to obtain in vivo pigments spectral signatures. The architectural features were obtained by imaging the biofilms with a confocal laser scanning microscopy and an optical coherence tomography. Overall, this experimental setup allowed us to follow the growth of two biofilm-forming microalgae showing that cell physiology is more affected in complex biofilms likely as a consequence of alterations in local environmental conditions.