Microbiome claims : to do or not to do ? / Ernesta Malinauskyte in GLOBAL PERSONAL CARE, Vol. 22, N° 8 (09/2021)

[article]  inGLOBAL PERSONAL CARE > Vol. 22, N° 8 (09/2021) . - p. 65-68 Titre : Microbiome claims : to do or not to do ? Type de document : texte imprimé Auteurs : Ernesta Malinauskyte, Auteur ; Marcella Gabarra Almeida Leite, Auteur Année de publication : 2021 Article en page(s) : p. 65-68 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Dermatologie Dermo-cosmétologie Microbiome cutané Index. décimale : 668.5 Parfums et cosmétiques Résumé : This article from TRI Princeton presents an overview of the skin microbiome and also the influence of cosmetic ingredients and the claims that can be made based on their activity. There is an ongoing debate regarding microbiome terminology in the microbiology field. In this paper, we will be using the following definitions: (i) Microbiota is defined as the live (or active) microorganisms present on the body, and (ii) microbiome is the community of these microorganisms and the ones that are not considered alive (phages, viruses, plasmids, prions, viroids, and free DNA), their environment and interaction amongst each other and their host. An additional difference between these two terms can be explained by how we study them. Microbiota can be studied separately from their natural environment (in vitro studies) however, the environment of microbiome studies must include all members of the microbiological "community" within its natural habitat1 despite that our interest might be only one strain. The microbiome is frequently evaluated while studying the genome of the microorganisms of interest. The microbiome is first formed when the newborn’s skin first makes a contact with the mother. The newborn’s digestive tract and skin become colonised by the mother's microorganisms which will later become part of its microbiome. This process is associated with the development and stimulation of the immune system. While studies show that the gut microbiome can influence the skin, in this paper, we will focus primarily on the relationship between skin microbiome and skin health. There are two types of microorganisms on the skin, the resident (commensal) and the transient. The commensal microorganisms reside on human skin throughout human life. Due to occasional perturbation, they might leave the skin, but will repopulate again. Meanwhile, the transient ones are not permanent, usually persisting for hours or days due to external conditions. The skin, along with these microorganisms, consists of a protective system against external aggressions. There is a balance in the composition of the skin’s components, called hydrolipidic balance, and the microbiome has its own balance that is established by a variety of healthy skin microorganisms networking with each other and the skin. When external factors promote alterations in any of these equilibria, dysbiosis occurs, making the skin more susceptible to the development of pathologies. Therefore, it is important to understand how the skin and its external conditions can affect the microbiome homeostasis and consequently promote alterations in the skin. Note de contenu : - How microbiome differs between body regions - Main issues associated with microbiome disbalance - The influence of regular cosmetic ingredients on microbiome - what is the effect of the substances that are designed to modulate skin microbiome ? - Regulations and limits for cosmetic manufacturers - So what can be done by cosmetic manufacturers ? Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=36602 [article]

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Penetration of different molecular weight hydrolysed keratins into hair fibres and their effects on the physical properties of textured hair / Ernesta Malinauskyte in INTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Vol. 43, N° 1 (02/2021)  

[article]  inINTERNATIONAL JOURNAL OF COSMETIC SCIENCE > Vol. 43, N° 1 (02/2021) . - p. 26-37 Titre : Penetration of different molecular weight hydrolysed keratins into hair fibres and their effects on the physical properties of textured hair Type de document : document électronique Auteurs : Ernesta Malinauskyte, Auteur ; R. Shrestha, Auteur ; P. A. Cornwell, Auteur ; Simon Gourion-Arsiquaud, Auteur ; M. Hindley, Auteur Année de publication : 2021 Article en page(s) : p. 26-37 Note générale : Bibliogr. Langues : Anglais (eng) Catégories : Cheveux -- Propriétés mécaniques Cheveux défrisés -- Soins et hygiène Cosmétiques Hydrolysats de protéines kératines La kératine est une protéine, synthétisée et utilisée par de nombreux êtres vivants comme élément de structure, et également l'exemple-type de protéine fibreuse. La kératine est insoluble, et peut être retrouvée sur l'épiderme de certains animaux, notamment les mammifères, ce qui leur garantit une peau imperméable. Parfois, lors d'une friction trop importante, la kératine se développe à la surface de la peau formant une callosité. Les cellules qui produisent la kératine meurent et sont remplacées continuellement. Les morceaux de kératine qui restent emprisonnés dans les cheveux sont couramment appelés des pellicules. La molécule de kératine est hélicoïdale et fibreuse, elle s'enroule autour d'autres molécules de kératine pour former des filaments intermédiaires. Ces protéines contiennent un haut taux d'acides aminés à base de soufre, principalement la cystéine, qui forment un pont disulfure entre les molécules, conférant sa rigidité à l'ensemble. La chevelure humaine est constituée à 14 % de cystéine. Il y a deux principales formes de kératines : l'alpha-kératine, ou α-keratin, présente chez les mammifères notamment, dont l'humain, et la bêta-kératine, ou β-keratin, que l'on retrouve chez les reptiles et les oiseaux. Ces deux types de kératines ne présentent clairement pas d'homologie de séquence. Chez l'être humain, la kératine est fabriquée par les kératinocytes, cellules se trouvant dans la couche profonde de l'épiderme. Les kératinocytes absorbent la mélanine (pigment fabriqué par les mélanocytes), se colorent et ainsi cette pigmentation de l'épiderme permet de protéger les kératinocytes des rayons ultraviolets du Soleil. (Wikipedia) Pénétration (physique) Peptides Poids moléculaires Produits capillaires Traction (mécanique) Index. décimale : 668.5 Parfums et cosmétiques Résumé : - Objective : To investigate the effects of different molecular weight (MW), wool derived hydrolysed keratins (i.e. peptides) on the physical properties of relaxed textured hair. - Methods : Very curly hair of African origin was relaxed using sodium hydroxide-based treatment. Relaxed hair was treated with different MW peptides derived from keratin protein and an amino acid, L-Leucine. The low-MW keratin peptides were 221 Da, the mid-MW keratin peptides were approximately 2577 Da, and the high-MW keratin peptides were approximately 75 440 Da. The penetration of these different peptides into relaxed hair was evaluated using a laser scanning micrometre and by fluorescence microscopy. The effect of these compounds on single-fibre mechanical properties and thermal properties was evaluated using tensile and DSC testing, respectively. - Results : Low- and mid-MW compounds were able to penetrate deep into the hair cortex. High-MW peptide adsorbed onto the hair surface and possibly slightly penetrated into the outer layers of the fibre surface. Both mid- and high-MW keratin peptides, increased Young’s modulus and reduced hair breakage at 20% and 80% relative humidity. With the exception of mid-MW peptide, other peptides and amino acid were not able to modify thermal properties of relaxed textured hair. - Conclusions : Our data suggest that low-MW compounds may increase hair volume, and high-MW peptides may repair damage on freshly relaxed textured hair. Note de contenu : - MATERIALS AND METHODS : Hair samples - Relaxing procedure - Amino acid and keratin peptide ingredients - Preparation of fluorescently labelled keratin peptides - Penetration of labelled keratin peptides into hair fibres - Scanning electron microscopy - Hair diameter and single-fibre tensile testing studies - Differential scanning calorimetry - Statistical analysis - RESULTS : Effects of peptide treatments on fibre cross-sectional area - Penetration of labelled keratin peptides into hair fibres - Pre-existing mechanical damage of hair via SEM - Surface coverage by mid- and high-MW peptide treatments via SEM - Effects of peptide treatments on hair stiffness - Effects of peptide treatments on hair breakage - Effects of peptide treatments on thermal properties of hair DISCUSSION : Fluorescence microscopy - Penetration of keratin peptides - Effects of treatments on hair stiffness - Effects of treatments on hair breakage - Table : The treatment effect on the premature breakage (number of prematurely broken fibres per 50 tested fibres) DOI : https://doi.org/10.1111/ics.12663 En ligne : https://onlinelibrary.wiley.com/doi/epdf/10.1111/ics.12663 Format de la ressource électronique : Pdf Permalink : https://e-campus.itech.fr/pmb/opac_css/index.php?lvl=notice_display&id=35441 [article]

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