Filamentous Forms Research Articles

Histopathological analysis of filament formation of Nocardia farcinica in a silkworm infection model.

The silkworm Nocardia infection model has been established as a useful animal model for screening the pathogenicity of Nocardia and evaluating the therapeutic effects of antimicrobial agents against Nocardia infection. No histopathological analysis of silkworms infected with Nocardia farcinica has yet been performed. In this study, we performed histological analyses on organs of silkworms infected with N. farcinica. One day after infection with N. farcinica, the organism developed a branching filamentous form from coccid cells in the hemolymph. In addition, we evaluated effective doses (ED50) values by treating infected silkworms with amikacin 30 seconds and 24 hours after infection and found that the ED50 values treated within 30 seconds and 24 hours after infection were 4.1 μg/larva and 5.6 μg/larva, respectively. Evaluation of treatment with amikacin against the infected silkworms was unaffected by the growth process form of Nocardia. These results suggest that the silkworm Nocardia infection model is a useful tool for evaluating the antimicrobial therapy in the growth process of the N. farcinica.

Bacteriological Evaluation of Indoor Air Quality in Some Selected Units at the University of Cape Coast Hospital in Ghana

A hospital is an environment solely for diagnosing and treating patients. Contemporary research, however, reveals the possibility of users contracting diseases due to many factors, such as poor air quality. This research, therefore, delves into the critical indoor air quality assessment domain, focusing on selected units within the University of Cape Coast Hospital, Ghana. The study’s primary objective was to conduct a comprehensive microbial assessment of indoor air quality in eight different units (emergency room, operating theater, out-patient department, consulting rooms, laboratory, male ward, female ward, and ear, nose, and throat unit) of the hospital, shedding light on potential airborne bacteria present. Indoor and outdoor air were sampled using Koch’s sedimentation method. Colony forming units per cubic meter of air (cfu/m3) were determined with the Omeliansky formula. The bacteriological load within the units revealed that the out-patient department had the highest bacterial concentration (139.2±60.32×102 cfu/m3), immediately followed by Outdoor (135.1±43.63×102 cfu/m3), whereas ear, nose, and throat unit recorded the least concentration (0.4±0.57×102 cfu/m3). The remaining units range between 135.1±43.63×102 cfu/m3 and 0.4±0.57×102 cfu/m3. The morphological characteristics of the seven observed bacterial isolates (GSB 1-7) showed the presence of two cocci and five rods. Isolates 1 and 4 had a rhizoid form, isolates 2,3, and 5 had a circular form, while isolates 6 and 7 had filamentous forms. All isolates showed positive gram tests, and endospores were detected in isolates 1, 4, and 6. Bacterial isolates were identified as Bacillus mycoides, Micrococcus luteus, Staphylococcus epidermidis, Bacillus circulans, Staphylococcus saprophyticus, Bacillus subtilis, and Micrococcus sp. These outcomes indicate bacterial contaminations in the indoor environment, likely to pose a significant risk to patients, workers, and visitor’s safety. Therefore, rigorous monitoring and mitigation strategies are essential to ensure a safer environment in healthcare settings.

The biochemically defined super relaxed state of myosin—A paradox

The biochemical SRX (super-relaxed) state of myosin has been defined as a low ATPase activity state. This state can conserve energy when the myosin is not recruited for muscle contraction. The SRX state has been correlated with a structurally defined ordered (versus disordered) state of muscle thick filaments. The two states may be linked via a common interacting head motif (IHM) where the two heads of heavy meromyosin (HMM), or myosin, fold back onto each other and form additional contacts with S2 and the thick filament. Experimental observations of the SRX, IHM, and the ordered form of thick filaments, however, do not always agree, and result in a series of unresolved paradoxes. To address these paradoxes, we have reexamined the biochemical measurements of the SRX state for porcine cardiac HMM. In our hands, the commonly employed mantATP displacement assay was unable to quantify the population of the SRX state with all data fitting very well by a single exponential. We further show that mavacamten inhibits the basal ATPases of both porcine ventricle HMM and S1 (Ki, 0.32 and 1.76μM respectively) while dATP activates HMM cooperatively without any evidence of an SRX state. A combination of our experimental observations and theories suggests that the displacement of mantATP in purified proteins is not a reliable assay to quantify the SRX population. This means that while the structurally defined IHM and ordered thick filaments clearly exist, great care must be employed when using the mantATP displacement assay.

Cell pleomorphism and changes in the enzymatic profile of selected Candida albicans strains in interaction with Escherichia coli – pilot study

Interactions between C. albicans and the microbiota play an important role in maintaining the balance between commensal and pathogenic organisms. Although the exact role of bacteria in reducing the pathogenicity of yeast remains poorly understood, a few examples have been documented so far: probiotics administration effectively reduces the formation of biofilm and bacterial metabolites inhibit the formation of hyphae.The aim of the study was to analyze C. albicans virulence levels based on the changes in the morphological structure and enzymatic profile in experimental cultures mixed with Escherichia coli. Viable cell abundance, cell pleomorphism and enzymatic profile were analyzed in single and mixed cultures (C. albicans + E. coli).The microscope analysis showed a large decrease in the number of viable C. albicans cells in mixed cultures with E. coli from 485.3±132.1 immediately after the establishment of the culture to 238.1±71.2 after an hour of incubation and 24.4±5.4 after 24 h. The length of C. albicans cells differed significantly between the single-species cultures and the mixed cultures for 24 h. Our present findings indicate a significant reduction in the secretion of several enzymes by fungi following contact with E. coli, including acid phosphatase, N-acetyl-β-glucosaminidase, naphthol-AS-BI-phosphohydrolase and leucine arylamidase.The interactions between fungi and bacteria appear to be extremely complex. On the one hand, during C. albicans with E. coli co-incubation, the bacteria stimulated the elongation of yeast cells, leading to the formation of a filamentous form; however, the number of yeast cells and their enzymatic activity decreased significantly. Therefore, it can be concluded that while E. coli stimulates some pathogenic properties, e.g. cell elongation, it also inhibits other virulence features, e.g. enzymatic activity of C. albicans.

Respiration supports intraphagosomal filamentation and escape of Candida albicans from macrophages.

Candida albicans is a leading human fungal pathogen that often causes life-threatening infections in immunocompromised individuals. The ability of C. albicans to transition between yeast and filamentous forms is key to its virulence, and this occurs in response to many host-relevant cues, including engulfment by host macrophages. While previous efforts identified C. albicans genes required for filamentation in other conditions, the genes important for this morphological transition upon internalization by macrophages remained largely enigmatic. Here, we employed a functional genomic approach to identify genes that enable C. albicans filamentation within macrophages and uncovered a role for the mitochondrial ribosome, respiration, and the SNF1 AMP-activated kinase complex. Additionally, we showed that glucose uptake and glycolysis by macrophages support C. albicans filamentation. This work provides insights into the metabolic dueling that occurs during the interaction of C. albicans with macrophages and identifies vulnerabilities in C. albicans that could serve as promising therapeutic targets.

Simulation of filamentation dynamics of microwave discharge in nitrogen

The present study deals with numerical simulations of microwave (MW) discharges in nitrogen based on extended fluid-dynamic model. The set of governing equations for non-equilibrium gas-discharge plasma includes conservation equations for species number densities, electron energy density, Poisson equation for the electric field coupled to the multi-temperature Navier–Stokes fluid-dynamic equations taking into account thermal nonequilibrium; the power transmitted from MW radiation to electrons is determined from the Helmholtz equation. The kinetic scheme includes 61 reactions involving neutral molecules and atoms in the ground and electronically excited states, ions and electrons. The set of equations is solved for a two-dimensional problem under conditions of experiments at a pressure of 40 and 50 Torr and different electromagnetic wave frequencies and pulse duration. The dynamics of discharge formation and transition from the diffuse to the filament form is studied. The results are compared with experimental data, and a good agreement is shown for the time larger than 10 µs. The possible reasons for discrepancies at a shorter time are discussed and the effect of small oxygen impurities on the quantitative characteristics of the discharge are evaluated. The presence of a small oxygen impurity and seed electrons in the region of discharge formation yields a better agreement between numerical and experimental data.

Multi-Omics Profiling of Candida albicans Grown on Solid Versus Liquid Media.

Candida albicans is a common pathogenic fungus that presents a challenge to healthcare facilities. It can switch between a yeast cell form that diffuses through the bloodstream to colonize internal organs and a filamentous form that penetrates host mucosa. Understanding the pathogen's strategies for environmental adaptation and, ultimately, survival, is crucial. As a complementary study, herein, a multi-omics analysis was performed using high-resolution timsTOF MS to compare the proteomes and metabolomes of Wild Type (WT) Candida albicans (strain DK318) grown on agar plates versus liquid media. Proteomic analysis revealed a total of 1793 proteins and 15,013 peptides. Out of the 1403 identified proteins, 313 proteins were significantly differentially abundant with a p-value < 0.05. Of these, 156 and 157 proteins were significantly increased in liquid and solid media, respectively. Metabolomics analysis identified 192 metabolites in total. The majority (42/48) of the significantly altered metabolites (p-value 0.05 FDR, FC 1.5), mainly amino acids, were significantly higher in solid media, while only 2 metabolites were significantly higher in liquid media. The combined multi-omics analysis provides insight into adaptative morphological changes supporting Candida albicans' life cycle and identifies crucial virulence factors during biofilm formation and bloodstream infection.

Investigation of electrical, electromagnetic interference shielding and tensile properties of 3D-printed acrylonitrile butadiene styrene/carbon nanotube composites

Conductive polymer composites (CPCs) are manufactured by compounding conductive particles with a polymer matrix. There are many applications where they are used, including light-weight applications requiring both electrical and heat conductivity. Carbon nanotubes (CNTs) have been accepted as common materials to accomplish this goal. As part of this research, a material extrusion additive manufacturing (AM) process was utilized to create nanocomposites by a 3D-printing technique. Multi-wall carbon nanotubes (MWCNTs) were mixed in 1, 3 and 6 wt fractions with acrylonitrile butadiene styrene (ABS) and extruded in filament form. Three-dimensionally printed specimens were used to evaluate electrical, electromagnetic interference shielding effectiveness (EMI SE) and tensile properties. The electrical conductivity of the material was 26 times greater than that of ABS. In the X-band of electromagnetic waves, EMI SE's reflected and absorbed portions increased respectively 4 and 16 times. The tensile strength and modulus were enhanced by 15% and 9%, respectively. On composite specimens, microwave heat treatment was applied. There is less void space between the rasters and layers, which helps improve tensile properties. Additionally, 3D-printed specimens were tested for melt flow rate (MFR) and dynamic mechanical behaviour. The nozzle has experienced some wear due to the intrinsic abrasive nature of CNTs.

Exploring the Biomedical Potential of PLA/Dysprosium Phosphate Composites via Extrusion-Based 3D Printing: Design, Morphological, Mechanical, and Multimodal Imaging and Finite Element Modeling.

The present investigation demonstrates the feasibility of dysprosium phosphate (DyPO4) as an efficient additive in polylactide (PLA) to develop 3D printed scaffolds through the material extrusion (MEX) principle for application in bone tissue engineering. Initially, uniform sized particles of DyPO4 with tetragonal crystal setting are obtained and subsequently blended with different concentrations of PLA to extrude in the form of filaments. A maximum of 20 wt % DyPO4 in PLA matrix has been successfully drawn to yield a defect free filament. The resultant filaments were 3D printed through material extrusion methodology. The structural and morphological analysis confirmed the successful reinforcement of DyPO4 throughout the PLA matrix in all of the 3D printed components. All of the PLA/DyPO4 composites exhibited magnetic resonance imaging and computed tomography contrasting properties, which were dependent on the dysprosium content in the PLA matrix. The detailed mechanical evaluation of the 3D printed PLA/DyPO4 composites ensured good strength accomplished by the reinforcement of 5 wt % DyPO4 in PLA matrix, beyond which a gradual decline in the strength is noticed. Representative volume elements models were developed to realize the intrinsic property of the PLA/DyPO4 composite, and finite element analysis under both static and dynamic loading conditions has been performed to account for the reliability of experimental results.

Poly-Lactic Acid-Bagasse Based Bio-Composite for Additive Manufacturing.

Beer bagasse is a residue waste produced in great amounts; nevertheless, it is still underestimated in the industry. The aim of this paper is to develop an innovative and efficient methodology to recycle the beer bagasse by producing Poly-lactic acid(PLA)-based bio-composites, in the forms of pellets and filaments, to be used in additive manufacturing processes. To assess the suitability of beer bagasse for extrusion-based 3D printing techniques, it was, firstly, physically and chemically characterized. Then, it was added in combination with different kinds of plasticizers to PLA to make bio-composites, analyzing their thermal and physical properties. The results prove the great potential of bagasse, evidencing its printability. Both composites' pellets and filaments were used in two different 3D printing machines and the mechanical properties of the 3D-printed models were evaluated as a function of the composition and the kind of technology used. All the used plasticizers improved processability and the polymer-bagasse interface. Compared to neat PLA, no changes in thermal properties were detected, but a lowering of the mechanical properties of the 3D-printed composites compared to the neat polymers was observed. Finally, a comparison between the efficiency of the two 3D printing techniques to be used with the bio-based composites was performed.

Exploring different methodological approaches to unlock paleobiodiversity in peat profiles using ancient DNA

Natural and human-induced environmental changes deeply affected terrestrial ecosystems throughout the Holocene. Paleoenvironmental reconstructions provide information about the past and allow us to predict/model future scenarios. Among potential records, peat bogs are widely used because they present a precise stratigraphy and act as natural archives of highly diverse organic remains. Over the decades, several techniques have been developed to identify debris occurring in peat, including their morphological description. However, this is strongly constrained by the researcher's ability to distinguish residues at the species level, which typically requires many years of experience. In addition, potential contamination hampers using these techniques to obtain information from organisms such as fungi or bacteria. Environmental DNA metabarcoding and shotgun metagenome sequencing could represent a solution to detect specific groups of organisms without any a priori knowledge of their characteristics and/or to identify organisms that have rarely been considered in previous investigations. Moreover, shotgun metagenomics may allow the identification of bacteria and fungi (including both yeast and filamentous life forms), ensuring discrimination between ancient and modern organisms through the study of deamination/damage patterns. In the present review, we aim to i) present the state-of-the-art methodologies in paleoecological and paleoclimatic studies focusing on peat core analyses, proposing alternative approaches to the classical morphological identification of plant residues, and ii) suggest biomolecular approaches that will allow the use of proxies such as invertebrates, fungi, and bacteria, which are rarely employed in paleoenvironmental reconstructions.

A Comprehensive Mechanical Examination of ABS and ABS-like Polymers Additively Manufactured by Material Extrusion and Vat Photopolymerization Processes.

Additive manufacturing technologies have developed rapidly in recent decades, pushing the limits of known manufacturing processes. The need to study the properties of the different materials used for these processes comprehensively and in detail has become a primary goal in order to get the best out of the manufacturing itself. The widely used thermoplastic polymer material acrylonitrile butadiene styrene (ABS) was selected in the form of both filaments and ABS-like resins to investigate and compare the mechanical properties through a series of different tests. ABS-like resin material is commercially available, but it is not a sufficiently mechanically studied form of the material, which leads to the rather limited literature. Considering that ABS resin is a declared material that behaves like the ABS filament but in a different form, the objective of this study was to compare these two commercially available materials printed with three different 3D printers, namely Fused Deposition Modelling (FDM), Stereolithography (SLA) and Digital Light Processing (DLP). A total of 45 test specimens with geometries and test protocols conforming to the relevant standards were subjected to a series of tensile, three-point bending and compression tests to determine their mechanical properties. Characterization also included evaluation of morphology with 2D and 3D microscopy, dimensional accuracy of 3D scans, and Shore A hardness of each material and 3D printing process. Tensile testing results have shown that FDM toughness is 40% of the value for DLP. FDM elongation at break is 37% of DLP, while ultimate tensile stress for SLA is 27% higher than FDM value. Elastic modulus for FDM and SLA coincide. Flexure testing results indicate that value of DLP flexural modulus is 54% of the FDM value. SLA strain value is 59% of FDM, and DLP ultimate flexure stress is 77% of the value for FDM. Compression test results imply that FDM specimens absorb at least twice as much energy as vat polymerized specimens. Strain at break for SLA is 72% and strain at ultimate stress is 60% of FDM values. FDM yield stress is 32% higher than DLP value. SLA ultimate compressive stress is half of FDM, while value for DLP compressive modulus is 69% of the FDM value. The results obtained are beneficial and give a more comprehensive picture of the behavior of the ABS polymers used in different forms and different AM processes.

Contaminants and Human Health Risks Associated with Exposure to Microplastic Ingestion of Green Mussels (Perna viridis) Collected from The Kedonganan Fish Market, Bali

Microplastics (MPs) are pollutant agents that have been absorbed and detected in aquatic ecosystems at high concentrations. This study aimed to investigate the presence of MPs pollution in green mussel (Perna viridis) products sold at the Kedonganan fish market, Badung, Bali. A total of 150 mussels with an average weight of 3,2 ± 0,71 g/mussels from three traders each composed and followed by the pre-treatment stage using 5 M NaCl solution, extraction with wet oxidation peroxidation (WPO) + Fe(II) catalyst and filtered. The highest percentage for the form of MPs was successively obtained by the Line form in Trader A at 85,42% and the lowest in Trader C at 50,00%. The highest form of fragments was obtained in Trader C at 42,86%. Film and filament forms were only obtained in Trader A. The highest MPs color was black and the lowest was gray. The highest average MPs particle size was found in the form of a filament of 1944,37 ± 88,41 μm which was found in Trader A. Estimates of MPs intake per year/capita in Indonesia showed that exposure to MPs through consumption of green mussels in this study amounted to 498,330 MPs/year/capita items. Overall, the green mussel from Trader A had the highest percentage and size of MPs, with the shape of fragment MPs being dominated by Trader C and the color of the MPs being dominated by black. MPs exposure to green mussel consumption in Indonesia is very high, but no health impact category has yet been found for this estimate.

The induction of tau aggregation is restricted by sulfamethoxazole and provides new information regarding the use of the drug

The aggregation of tau protein in the form of paired helical filament (PHF) leads to the breakdown of microtubule structure and the development of neurodegenerative disorders, such as Alzheimer’s disease. Therefore, inhibiting tau protein aggregation is a potential strategy for preventing the progression of these disorders. In this study, sulfamethoxazole (SMZ), an antibiotic that easily crosses the blood-brain barrier and interacts with tau protein, was tested for its ability to inhibit tau aggregation in vitro. Various multi-spectroscopic techniques including XRD, LDH cytotoxicity colorimetric assay, and microscopic imaging were employed. The results showed that SMZ effectively interacts with tau protein through hydrogen and van der Waals interactions. It also effectively inhibited tau protein aggregation in vitro and significantly reduced toxicity in the SH-SY5Y neuroblastoma cell line. Molecular docking and MD simulation results suggested that SMZ may reduce tau protein aggregation by interacting with the PHF6 motif. Overall, these findings indicate that SMZ has therapeutic potential as a tau protein aggregation inhibitor, at least under in vitro conditions. These findings suggest that SMZ has potential as a treatment for neurodegenerative disorders involving tau protein aggregation. However, further research is needed to confirm these results and assess the effectiveness of SMZ in animal models and clinical trials. Communicated by Ramaswamy H. Sarma

Mold and Mycotoxin Exposure and Brain Disorders.

Gene-environment interaction is an emerging hypothesis to explain the increased incidence of neurological disorders. In this context, the health and clinical effects of exposure to air pollutants have received increasing attention. One of these pollutants is the growth of fungi and molds in the form of multicellular filaments, known as hyphae. Fungi and molds not only grow in outdoor environments, but they also thrive indoors with excessive moisture, producing mycotoxins. Mold enters the body through the nose via the olfactory neurons, which directly communicate with the brain. Mycotoxins induce toxicological effects similar to those associated with brain disorders such as oxidative stress and inflammation. One mold species can produce several different mycotoxins, and one mycotoxin can be produced by several different molds. Even a small amount of mold growth in the air conditioners and their ducts or the panels inside the buildings and even the cars cause the occupants to be chronically exposed to and constantly inhaling spores and mycotoxins, which causes illness. In this review, we focused on mold and mycotoxin exposure and brain disorders.

Expression of bovine annexin A4 in E. coli rescues cytokinesis blocked by beta-lactam antibiotics

Treatment of bacteria with beta-lactam antibiotics can impair the process of cytokinesis, the final step in cell division, leading to the formation of a filamentous form of the bacteria. The expression of a mammalian calcium-dependent, membrane-binding protein, bovine annexin A4, in E. coli was found to reverse the inhibitory effects on cytokinesis of the beta-lactam antibiotics ampicillin, piperacillin, and cephalexin. This novel activity of the annexin was blocked by mutation of calcium binding sites in the annexin, indicating roles for calcium binding to the annexin and the binding of the annexin to membranes in restoring cytokinesis. The filamentous form of the bacteria has been reported to be more resistant to phagocytosis by cells of the immune system in eukaryotic hosts. Therefore, expression of annexins in pathogenic bacteria, by promoting the breakdown of the bacterial filaments, might serve as an adjuvant to enhance the efficacy of beta-lactam antibiotics.

Immunomodulatory Potential of Fungal Extracellular Vesicles: Insights for Therapeutic Applications.

Extracellular vesicles (EVs) are membranous vesicular organelles that perform a variety of biological functions including cell communication across different biological kingdoms. EVs of mammals and, to a lesser extent, bacteria have been deeply studied over the years, whereas investigations of fungal EVs are still in their infancy. Fungi, encompassing both yeast and filamentous forms, are increasingly recognized for their production of extracellular vesicles (EVs) containing a wealth of proteins, lipids, and nucleic acids. These EVs play pivotal roles in orchestrating fungal communities, bolstering pathogenicity, and mediating interactions with the environment. Fungal EVs have emerged as promising candidates for innovative applications, not only in the management of mycoses but also as carriers for therapeutic molecules. Yet, numerous questions persist regarding fungal EVs, including their mechanisms of generation, release, cargo regulation, and discharge. This comprehensive review delves into the present state of knowledge regarding fungal EVs and provides fresh insights into the most recent hypotheses on the mechanisms driving their immunomodulatory properties. Furthermore, we explore the considerable potential of fungal EVs in the realms of medicine and biotechnology. In the foreseeable future, engineered fungal cells may serve as vehicles for tailoring cargo- and antigen-specific EVs, positioning them as invaluable biotechnological tools for diverse medical applications, such as vaccines and drug delivery.

The Impact Of Carbon Fiber on the surface properties of the 3D Printed PEGT Product

The primary focus of this work is the development of a hybrid composite material for 3D filaments. Polyethylene phthalate glycol (PETG) and (PETG/Carbon) fiber composite materials have their surface properties (surface roughness, Shore hardness, and micro hardness) tested. A ratio of 15% carbon fiber (in the form of carbon filaments) was used as the reinforcing filler. Using FDM (fused deposition modeling material) technology, the surface properties of PETG material used in 3D printed objects were enhanced. An ENDER 3D printer was used to create three PETG and PETG/Carbon fiber samples, using the printer setting 240°C temperature, 80°C build plate temperature, 55mm/s speed, 0.2mm layer height and speed fan 100mm/s. After that, an optical microscope and FT-IR technologies were used to investigate the samples. Results showed that as compared to PETG, the surface roughness of PETG/Carbon was reduced by 32.7%. This allowed carbon fiber to break doubly bonded in the PETG structure and also enhanced sample flow and adhesion. The PETG/Carbon samples had a Shore hardness D that was 2.16% lower than PETG's, but a slightly higher Micro hardness, making them more comparable to 10.4 HV than to 9.6 HV. However, the carbon fiber was reinforced and showed high compatibility with a PETG polymer matrix at the samples' buried structures, demonstrating that a 3D printer is an effective production tool for producing homogenized composite materials. According to claims, these features enhance the carbon fiber's ability to slide in PETG/Carbon samples.

Influence of Building Position and Printing Scheme on Mechanical Properties of Fused Filament Fabrication PLA Specimens

AbstractThe recent improvement of additive manufacturing (AM) technologies has been attracting the industry and research community attention. This paper aims to investigate the influence of building position and printing scheme on the tensile mechanical properties of Tough polylactic acid (PLA) material, manufactured through a fused deposition modeling (FDM) 3D printing – the S5 ProBundle Ultimaker. FDM 3D printing, also known as fused filament fabrication (FFF), is an AM process within the realm of material extrusion. FDM builds parts Layer by Layer by selectively depositing melted material in a predetermined path, and uses thermoplastic polymers that come in the form of filaments. In this paper, AM Tough PLA specimens are manufactured according to ASTM‐D638 requirement considering two different positions on the building plate and two printing schemes. Specimens are tested under static tensile test and the mechanical properties are extracted.

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.