Changes In Fluidity Research Articles

Sociodemographic Patterns in Retrospective Sexual Orientation Identity and Attraction Change in the Sexual Orientation Fluidity in Youth Study

PurposeThis study examined sociodemographic patterns of retrospective fluidity in sexual orientation identity (i.e., any change from one identity to another) and attractions (i.e., any change in attractions to one or more gender(s)) in a large sample of US youth. MethodsParticipants were 4,087 youth (58% cisgender girls/women, 38% cisgender boys/men, 5% transgender or nonbinary individuals), ages 14–25 years, from across the United States, who were recruited from an online survey panel. Sexual and gender minorities and people of color were oversampled. Participants completed the Wave 1 survey of the longitudinal Sexual Orientation Fluidity in Youth study, which assessed sociodemographic characteristics and retrospective fluidity in sexual orientation identity and attractions. ResultsAcross the sample, 17% reported a retrospective change in identity and 33% reported a change in attractions. Participants who were most likely to report identity change were in the younger age group (14–17 years), were transgender or nonbinary, had a plurisexual identity (pansexual, queer), and reported attractions to more than one gender. Participants who were most likely to report attraction change were nonbinary, had a plurisexual identity (pansexual, queer, bisexual), and reported attractions to more than one gender. DiscussionThis study found retrospective changes in sexual orientation identity and attractions were common in this sample of youth, with the prevalence of these changes differing by sociodemographic characteristics. Results from this study inform future research on adolescent health and have implications for supporting and caring for this age group, for whom sexual fluidity is common.

Transcriptome assessment in 'Red Globe' grapevine zygotic embryos during the cooling and warming phase of the cryopreservation procedure

Cryopreservation has the potential for long-term germplasm storage. The metabolic pathways and gene regulation involved in cryopreservation procedures are still not well documented. Hence, the genetic expression profile was evaluated using RNA-Seq in zygotic embryos of grapevines subjected to cryopreservation by vitrification. Sequencing was performed on the Illumina NextSeq 500. The average alignment of reads was 96% against the reference genome. The expression profiles showed 229 genes differentially expressed (186 repressed and 46 induced). The main biological processes showing upregulated enrichment were related to nucleosome assembly, while downregulated processes were related to organ growth. The most highly repressed processes were associated with the organization of the cell wall and membrane components. The unnamed protein product and 17.3 kDa class II heat shock protein (HSP) were highly induced, while ATPase subunit 1 and expansin-A1 were repressed. The response to the cooling and warming process during cryopreservation probably indicates that the changes occurring in transcription may be related to epigenetics. In addition, the cell exhibits an increase in the reserve of nutrients while seeking to survive modestly using available energy and pausing the plant's development. Additionally, energy containment occurred to cope with the stress caused by the treatment where deactivation of components of the cell membrane was observed, possibly due to changes in fluidity caused by alterations in temperature.

Tracking Global and Local Changes in Membrane Fluidity Through Fluorescence Spectroscopy and Microscopy.

Membrane fluidity is a critical parameter of cellular membranes, which cells continuously strive to maintain within a viable range. Interference with the correct membrane fluidity state can strongly inhibit cell function. Triggered changes in membrane fluidity and associated impacts on lipid domains have been postulated to contribute to the mechanism of action of membrane targeting antimicrobials, but the corresponding analyses have been hampered by the absence of readily available analytical tools. Here, we expand upon the protocols outlined in the first edition of this book, providing further and alternative protocols that can be used to measure changes in membrane fluidity. We provide detailed protocols, which allow straightforward in vivo and in vitro measurement of antibiotic compound-triggered changes in membrane fluidity and fluid membrane microdomains. Furthermore, we summarize useful strains constructed by us and others to characterize and confirm lipid specificity of membrane antimicrobials directly in vivo.

Thermosensing in plants: Deciphering the mechanisms involved in heat sensing and their role in thermoresponse and thermotolerance

With a gradual increase in the ambient temperature plants need to perceive these changes accurately and adjust accordingly in order to adapt and survive. Heat stress affects various developmental stages of plants and adversely impacts yield. Therefore, approaches for developing crops with heat tolerance and high crop productivity have now become major agricultural goals. In the heat sensing process, high temperature causes several changes in various components of the cell, including changes in the membrane fluidity, calcium ions, cytoskeleton elements and protein unfolding. Although some information regarding the signaling mechanisms activated upon sensing of high temperature has been available, only recently new insights have been gained in the thermosensing mechanisms in plants. This review focuses on the various molecular changes that occur within a cell with the rise in temperature and how these are linked to thermomorphogenesis and thermotolerance. Moreover, in the light of upcoming research, the role of photoreceptors, phytohormones, DNA and RNA in heat perception has been given greater attention. • Detrimental effects of heat stress on plants. • Role of various cellular components i.e. cell membranes, proteins, cytoskeleton elements, DNA and RNA in heat perception. • Sensing of high ambient temperature leads to two different responses i.e. thermomorphogenesis and thermotolerance. • Photoreceptor function as thermosensor.

Dissecting the molecular mechanisms of producing biofuel and value-added products by cadmium tolerant microalgae as sustainable biorefinery approach

Microalgae can reconcile the deteriorating outcomes of environmental pollution by conserving the carbon footprint and generating green energy. Among different pollutants, cadmium (Cd) is one of the most noxious heavy metals that travels the ecological chain via phytoplanktons and stagnates the nutritional quality of aquatic life. In the present study, Scenedesmus sp. IITRIND2, a reported Cd-tolerant algal strain, has been subjected to detailed molecular investigations through metabolomics, gene expression, and biochemical analysis to dissect the pathways involved in Cd tolerance and the carbon flux channelization resulting in enhanced lipid/extracellular polysaccharide (EPS) production. The metabolic rewiring in the tricarboxylic acid (TCA) intermediates, amino acid metabolism, and starch metabolism presented the robust machinery of the cells to channelize the carbon pools for producing neutral lipids of vehicular quality under Cd stress. Further, microalgal cells instigated a defense network comprising organic osmolytes (betaine, ethylene glycol, sugars), antioxidants (glutathione, ascorbate, etc.,) and amino acids (glycine, glutamate, alanine, valine, threonine) suggesting the interplay of glutathione-ascorbate and probable phytochelatin based detoxification pathways as double edge sword to impart tolerance and detoxification of Cd. Moreover, stress-induced response constituted significant changes in the membrane fluidity and production of biodiesel quality lipids along with soluble EPS having paramount biotechnological applications. The outcomes of this study altogether presented an efficient model of algal-based biorefinery approach integrating the process of heavy metal (Cd) remediation and production of biodiesel and value-added products that are essential for a sustainable and circular economy.

Effect of Al on the fluidity of Zn-3Mg alloy

The effect of adding different Al contents on the fluidity of Zn-3Mg alloy was investigated. The experimental results show that the addition of 1–4 wt% Al improves the fluidity of the alloy, while higher Al content decreases the fluidity of the alloy. The fluidity of Zn-3Mg-4Al is the best with a 24% improvement over the base alloy. By studying the structure evolution, macroscopic segregation, and melting behavior of Zn-3Mg-xAl, the Zn-3Mg-xAl fluidity change law and melt flow stopping mechanism were analyzed and discussed.

Investigating the Characteristics of Wet Shotcrete Pipeline Transportation

In order to study the resistance characteristics of wet shotcrete pipeline transportation, a small pipe type rheology and resistance test device was developed. The device is used for straight pipe resistance test, pump stop test and dyed concrete test were carried out on concrete with different characteristics. The fluidity changes of concrete with different characteristics were obtained through experiments. The results show that the slump, pressure bleeding rate, water-cement ratio were all negatively related to pipeline transportation resistance. The influence of the three factors on resistance was in order: pressure bleeding rate, water-cement ratio, slump. The dyed concrete test confirmed the principle of the plunger flow in the pipeline when concrete is pumped. The thickness of the lubricating layer increased with the increase of the water-cement ratio. The concrete pipeline transportation resistance increased with the increase of the standing time. The fitting curve was obtained through the correlation analysis between resistance and lubricating layer thickness, and the two were negatively correlated. This provides a new research idea for the study of drag reduction measures for concrete pipeline transportation.

Spectral Phasor Analysis of Nile Red Identifies Membrane Microenvironment Changes in the Presence of Amyloid Peptides.

The interaction of protein and peptide amyloid oligomers with membranes is thought to be one of the mechanisms contributing to cellular toxicity. However, techniques to study these interactions in the complex membrane environment of live cells are lacking. Spectral phasor analysis is a recently developed biophysical technique that can enable visualisation and analysis of membrane-associated fluorescent dyes. When the spectral profile of these dyes changes as a result of changes to the membrane microenvironment, spectral phasor analysis can localise those changes to discrete membrane regions. In this study, we investigated whether spectral phasor analysis could detect changes in the membrane microenvironment of live cells in the presence of fibrillar aggregates of the disease-related Aβ42 peptide or the functional amyloid neurokinin B. Our results show that the fibrils cause distinct changes to the microenvironment of nile red associated with both the plasma and the nuclear membrane. We attribute these shifts in nile red spectral properties to changes in membrane fluidity. Results from this work suggest that cells have mechanisms to avoid or control membrane interactions arising from functional amyloids which have implications for how these peptides are stored in dense core vesicles. Furthermore, the work highlights the utility of spectral phasor analysis to monitor microenvironment changes to fluorescent probes in live cells.

Structural details on the interaction of fenamates with lipid membranes

Fenamates are nonsteroidal anti-inflammatory drugs (NSAID), usually prescribed to treat pain and inflammation and, like other NSAIDs, to inhibit cyclooxygenases. They have also been proposed to show anti-epileptic and neuroprotective effects. In the current work, the interaction of several fenamates with phospholipid membranes was studied using various NMR techniques. One of the most important properties of membranes that influences the function and localization of proteins is their fluidity. Changes in membrane fluidity can also affect a drug’s ability to bind to and permeate through the membrane, which influences its efficacy. We studied the interaction of several fenamates with zwitterionic palmitoyloleoylphosphatidylcholine (POPC) membranes. Based on 1H NMR-induced chemical shift data and quantitative analysis of 1H MAS NOESY cross-relaxation rates, three fenamates (mefenamic, flufenamic and tolfenamic acid) were shown to penetrate the lipid membrane and are dynamically distributed within the bilayer. The average position of each drug in the lipid-water interface was also estimated from these measurements. 2H NMR data showed that binding of tolfenamic and mefenamic acid increases lipid chain order, while flufenamic acid slightly decreased lipid chain order in the lower segments of POPC membranes.

Serum phosphate is not an early predictor of neurocognitive outcomes in acute carbon monoxide poisoning patients.

Carbon monoxide (CO) poisoning causes brain injury by hypoxia and inflammatory mechanisms. Hypoxic conditions result in increased serum phosphate concentration due to loss of polarity of the cell membrane, changes in membrane fluidity, and consequent destruction of phospholipids in the cell membrane. This study aimed to evaluate whether serum phosphate measured in the emergency department (ED) can serve as an early predictor of neurocognitive sequelae 1 month after acute CO poisoning. We included patients ≥16 years with acute CO poisoning from a cohort who were treated at a single tertiary academic hospital in Wonju, Korea, between January 2006 and May 2021. Neurocognitive outcome was assessed using the Global Deterioration Scale score; patients were classified into favorable (1-3 points) or poor (4-7 points) neurocognitive outcome groups based on this score. These two groups were compared before and after propensity score matching. Data from 888 patients were analyzed. Seven hundred seventy-one patients (86.8%) were assigned to the favorable outcome group and 117 patients (13.2%) to the poor outcome group. Patients with a poor outcome had a higher mean serum phosphate level than those with a favorable outcome (3.9 mg/dL vs. 3.5 mg/dL, P=0.001). Propensity score matching yielded 85 matched patient pairs. After matching, serum phosphate level in the ED was not significantly different between the favorable and poor outcome groups (3.9 vs. 3.7 mg/dL, P=0.349). Serum phosphate level measured in the ED did not predict poor neurocognitive outcomes 1 month after CO poisoning.

The Flavonoid Molecule Procyanidin Reduces Phase Separation in Model Membranes.

Procyanidin extracted from fruits, such as apples, has been shown to improve lipid metabolization. Recently, studies have revealed that procyanidin interacts with lipid molecules in membranes to enhance lipid metabolism; however, direct evidence of the interaction between procyanidin and lipid membranes has not been demonstrated. In this study, the phase behaviors and changes in the membrane fluidity of cell-sized liposomes containing apple procyanidin, procyanidin B2 (PB2), were demonstrated for the first time. Phase separation in 1,2-Dioleoyl-sn-glycero-3-phosphocholine (DOPC)/1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC)/cholesterol ternary membranes significantly decreased after the addition of PB2. The prospect of applying procyanidin content measurements, using the results of this study, to commercial apple juice was also assessed. Specifically, the PB2 concentrations were 50%, 33%, and 0% for pure apple juice, 2-fold diluted apple juice, and pure water, respectively. The results of the actual juice were correlated with PB2 concentrations and phase-separated liposomes ratios, as well as with the results of experiments involving pure chemicals. In conclusion, the mechanism through which procyanidin improves lipid metabolism through the regulation of membrane fluidity was established.

Polyvinyl Chloride Nanoparticles Affect Cell Membrane Integrity by Disturbing the Properties of the Multicomponent Lipid Bilayer in Arabidopsis thaliana.

The ubiquitous presence of nanoplastics (NPs) in natural ecosystems is a serious concern, as NPs are believed to threaten every life form on Earth. Micro- and nanoplastics enter living systems through multiple channels. Cell membranes function as the first barrier of entry to NPs, thus playing an important biological role. However, in-depth studies on the interactions of NPs with cell membranes have not been performed, and effective theoretical models of the underlying molecular details and physicochemical behaviors are lacking. In the present study, we investigated the uptake of polyvinyl chloride (PVC) nanoparticles by Arabidopsis thaliana root cells, which leads to cell membrane leakage and damage to membrane integrity. We performed all-atom molecular dynamics simulations to determine the effects of PVC NPs on the properties of the multicomponent lipid bilayer. These simulations revealed that PVCs easily permeate into model lipid membranes, resulting in significant changes to the membrane, including reduced density and changes in fluidity and membrane thickness. Our exploration of the interaction mechanisms between NPs and the cell membrane provided valuable insights into the effects of NPs on membrane structure and integrity.

Changes of cell membrane fluidity for mesenchymal stem cell spheroids on biomaterial surfaces.

BACKGROUNDThe therapeutic potential of mesenchymal stem cells (MSCs) in the form of three-dimensional spheroids has been extensively demonstrated. The underlying mechanisms for the altered cellular behavior of spheroids have also been investigated. Cell membrane fluidity is a critically important physical property for the regulation of cell behavior, but it has not been studied for the spheroid-forming cells to date.AIMTo explore the association between cell membrane fluidity and the morphological changes of MSC spheroids on the surface of biomaterials to elucidate the role of membrane fluidity during the spheroid-forming process of MSCs.METHODSWe generated three-dimensional (3D) MSC spheroids on the surface of various culture substrates including chitosan (CS), CS-hyaluronan (CS-HA), and polyvinyl alcohol (PVA) substrates. The cell membrane fluidity and cell morphological change were examined by a time-lapse recording system as well as a high-resolution 3D cellular image explorer. MSCs and normal/cancer cells were pre-stained with fluorescent dyes and co-cultured on the biomaterials to investigate the exchange of cell membrane during the formation of heterogeneous cellular spheroids.RESULTSWe discovered that vesicle-like bubbles randomly appeared on the outer layer of MSC spheroids cultured on different biomaterial surfaces. The average diameter of the vesicle-like bubbles of MSC spheroids on CS-HA at 37 °C was approximately 10 μm, smaller than that on PVA substrates (approximately 27 μm). Based on time-lapse images, these unique bubbles originated from the dynamic movement of the cell membrane during spheroid formation, which indicated an increment of membrane fluidity for MSCs cultured on these substrates. Moreover, the membrane interaction in two different types of cells with similar membrane fluidity may further induce a higher level of membrane translocation during the formation of heterogeneous spheroids. CONCLUSIONChanges in cell membrane fluidity may be a novel path to elucidate the complicated physiological alterations in 3D spheroid-forming cells.

Interaction of Bortezomib with Cell Membranes Regulates Its Toxicity and Resistance to Therapy.

Bortezomib (BTZ) is a potent proteasome inhibitor currently being used to treat multiple myeloma. However, its high toxicity and resistance to therapy severely limit the treatment outcomes. Drug–membrane interactions have a crucial role in drugs’ behavior in vivo, affecting their bioavailability and pharmacological activity. Additionally, drugs’ toxicity often occurs due to their effects on the cell membranes. Therefore, studying BTZ’s interactions with cell membranes may explain the limitations of its therapy. Due to the cell membranes’ complexity, lipid vesicles were proposed here as biomembrane models, focusing on the membrane’s main constituents. Two models with distinct composition and complexity were used, one composed of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) and the other containing DMPC, cholesterol (Chol), and sphingomyelin (SM). BTZ’s interactions with the models were evaluated regarding the drugs’ lipophilicity, preferential location, and effects on the membrane’s physical state. The studies were conducted at different pH values (7.4 and 6.5) to mimic the normal blood circulation and the intestinal environment, respectively. BTZ revealed a high affinity for the membranes, which proved to be dependent on the drug-ionization state and the membrane complexity. Furthermore, BTZ’s interactions with the cell membranes was proven to induce changes in the membrane fluidity. This may be associated with its resistance to therapy, since the activity of efflux transmembrane proteins is dependent on the membrane’s fluidity.

Inositol acylation of phosphatidylinositol mannosides: a rapid mass response to membrane fluidization in mycobacteria

Mycobacteria share an unusually complex, multilayered cell envelope, which contributes to adaptation to changing environments. The plasma membrane is the deepest layer of the cell envelope and acts as the final permeability barrier against outside molecules. There is an obvious need to maintain the plasma membrane integrity, but the adaptive responses of the plasma membrane to stress exposure remain poorly understood. Using chemical treatment and heat stress to fluidize the membrane, we show here that phosphatidylinositol (PI)-anchored plasma membrane glycolipids known as PI mannosides (PIMs) are rapidly remodeled upon membrane fluidization in Mycobacterium smegmatis. Without membrane stress, PIMs are predominantly in a triacylated form: two acyl chains of the PI moiety plus one acyl chain modified at one of the mannose residues. Upon membrane fluidization, we determined the fourth fatty acid is added to the inositol moiety of PIMs, making them tetra-acylated variants. Additionally, we show that PIM inositol acylation is a rapid response independent of de novo protein synthesis, representing one of the fastest mass conversions of lipid molecules found in nature. Strikingly, we found that M. smegmatis is more resistant to the bactericidal effect of a cationic detergent after benzyl alcohol pre-exposure. We further demonstrate that fluidization-induced PIM inositol acylation is conserved in pathogens such as Mycobacterium tuberculosis and Mycobacterium abscessus. Our results demonstrate that mycobacteria possess a mechanism to sense plasma membrane fluidity change. We suggest that inositol acylation of PIMs is a novel membrane stress response that enables mycobacterial cells to resist membrane fluidization.

Change in membrane fluidity induced by polyphenols is highly dependent on the position and number of galloyl groups

The cell membrane fluidity was very important in adipogenesis and galloyl groups on polyphenolic structures could enhance their antiadipogenic activity. However, the effect of polyphenols on membrane fluidity and the role of galloyl groups in fluidity changes remain unclear. Therefore, the present study chose structurally different polyphenols to compare their effects on the membrane morphology and fluidity of 3T3-L1 preadipocytes, and then the reasons behind the changes of membrane fluidity induced by galloylated polyphenols were explored from structural and molecular insights using liposome model and molecular dynamic simulation technology. Our results indicated that galloylated polyphenols could significantly change 3T3-L1 cell membrane morphology and decrease membrane fluidity, while non-galloylated ones could not. The membrane interference effect of polyphenols was enhanced as the number of galloyl groups increased. Morever, the decrease in membrane fluidity induced by galloylated polyphenols was due to the disturbance of polyphenols on lipid alkyl chains in the cell membrane. Galloylated polyphenols could not only locate in the polar head, but also insert into hydrophobic center of lipid bilayer to interfere with the lipid alkyl chains arrangement, thus decreasing the membrane fluidity and showing strong affinity for the membrane. In addition, differences in position of galloyl groups in polyphenols induced distinct effect on cell membranes interactions, thus affecting the binding manner and bioactivity. The results expanded the understanding on the strong antiadipogenic activity of galloylated polyphenols through the aspect of their effects on cell membrane by both experimental and theoretically simulated ways.

How do humans and plants feel the heat?

The 2021 Nobel prize was awarded for the discovery of the animal thermosensory channel TRPV1. We highlight notable shared features with the higher plant thermosensory channel CNGC2/4. Both channels respond to temperature-induced changes in plasma membrane fluidity, leading to hyperphosphorylation of the HSF1 transcription factor via a specific heat-signaling cascade.

Effect of silica nanoparticles on cell membrane fluidity: The role of temperature and membrane composition

The increasing production and application of silica nanoparticles (SiO2 NPs) raise public concern regarding their environmental and health risks. The fluidity of the cell membrane is essential for supporting membrane proteins and regulating membrane transport. Changes in membrane fluidity inevitably influence the physiological activities of cells and even cause biological effects. In this study, the effect of SiO2 NPs on membrane fluidity was studied at 25 °C and 37 °C, and the role of membrane components in SiO2 NP-membrane interactions was investigated using giant plasma membrane vesicles (GPMVs) isolated from RBL-2H3 cells. SiO2 NPs cause a more serious membrane fluidity decrease at 37 °C than at 25 °C, which is revealed by the shift of Laurdan fluorescence emission and further quantified via forster resonance energy transfer (FRET) experiments. In addition, after the removal of 75 % cholesterol from the membrane, SiO2 NPs caused a greater extent of membrane gelation. These results indicate that SiO2 NPs prefer to interact with membranes that are more dynamic and less densely packed. Moreover, fluorescent experiments confirmed that the existence of phosphatidyl ethanolamine (PE) and phosphoinositide (PI) can mitigate NP-induced membrane gelation. Molecular dynamics simulation further demonstrated that SiO2 NPs form hydrogen bonds with the terminal of PE or PI but with the -PO4−- group in the middle of phosphatidylcholine (PC). The bonding that occurs in the terminal gives less restriction of phospholipid movement and a weaker effect on membrane fluidity. This research provides both evidence and mechanisms of SiO2 NP-induced membrane fluidity changes, which are helpful for understanding cell membrane damage and the biological effects of NPs.

Modulation of Cholesterol Pathways in Human Macrophages Infected by Clinical Isolates of Leishmania infantum.

To increase our understanding of factors contributing to therapeutic failure (TF) in leishmaniasis, we have studied some plasma membrane features of host THP-1 cells infected with clinical isolates of Leishmania infantum from patients with leishmaniasis and TF. The fluorescent probes DPH and TMA-DPH were used to measure changes in membrane fluidity at various depths of the plasma membranes. Steady-state fluorescence anisotropy of DPH embedded in the infected THP-1 membranes showed a significant increase, thereby suggesting a substantial decrease in plasma membrane fluidity relative to controls. Considering that cholesterol affects membrane fluidity and permeability, we determined the cholesterol content in plasma membrane fractions of human macrophages infected with these L. infantum lines and observed a significant increase in cholesterol content that correlates with the measured decrease in plasma membrane fluidity. In order to define the pathways that could explain the increase in cholesterol content, we studied the transcriptomics of the cholesterol-enriched pathways in host THP-1 cells infected with TF clinical isolates by RNA-seq. Specifically, we focused on four enriched Gene Ontology (GO) terms namely cholesterol efflux, cholesterol transport, cholesterol metabolic process and cholesterol storage. Additionally, we analyzed the genes involved in these pathways. Overall, this study shows that these clinical isolates are able to modulate the expression of specific genes in host cells, thereby modifying the cholesterol content in plasma membranes and inducing changes in plasma membrane fluidity that could be associated with the parasite’s ability to survive in the host macrophages, thereby possibly contributing to immune evasion and TF.

Sexual Fluidity and Attitudes towards Bisexuality

The following research provides an instrument to assess sexual fluidity changes over time in attractions and sexual orientation identity, thus examining whether experiencing sexual fluidity is related to specific cognitions, attitudes and beliefs among sexually and non-sexually fluid individuals. Participants (435 Spanish young adult students, 310 females and 125 males) completed an online form assessing demographic data, sexual orientation, sexual fluidity, and attitudes towards male and female bisexuality. An empirical sexual fluidity factor has been isolated: women scored higher than men (d = .68), and bisexual people higher than the homosexual (d = 1.74) and heterosexual (d = 1.40) groups. The study also highlights gender, sexual orientation and sexual fluidity differences in attitudes towards male and female bisexuality. Indeed, women consider male and female bisexuality more stable than men (d = .29 & d = .34); sexually fluid people show higher positive attitudes towards male and female bisexuality (d ranged .29 – .51) than the non-sexually fluid group; bisexual individuals scored higher in male and female bisexuality attitudes than heterosexual individuals. This study confirms previous research that showed that female individuals are more likely than male to have fluid sexuality. Attitudes about bisexuality are not a simple question: they are affected by gender, sexual orientation and sexual fluidity factors.