The adhesion of homogenized fat globules to proteins is increased by milk heat treatment and acidic pH: Quantitative insights provided by AFM force spectroscopy.

The rheological properties and microstructure of dairy gels involve the connectivity between milk fat globules (MFG) and casein micelles that is affected by technological processes such as milk homogenization and heat treatment. The underlying mechanisms require further quantification of the interactions at the nanoscale level to be fully understood and controlled. In this study, we examined the adhesion of homogenized MFG to milk proteins and evaluated the role of ultra-high temperature (UHT) heat treatment and pH.

The surface properties of milk fat globules govern their interactions with the caseins: Role of homogenization and pH probed by AFM force spectroscopy.

The surface of milk fat globules consists of a biological membrane rich in polar lipids and glycoproteins. However, high shear stress applied upon homogenization disrupts the membrane and leads to the adsorption of casein micelles, as the major protein fraction of milk. These changes in the interface properties could affect the interactions between native or homogenized milk fat globules and the surrounding protein matrix, at neutral pH and upon acidification.

Staphylococcus aureus induces DNA damage in host cell.

Staphylococcus aureus causes serious medical problems in human and animals. Here we show that S. aureus can compromise host genomic integrity as indicated by bacteria-induced histone H2AX phosphorylation, a marker of DNA double strand breaks (DSBs), in human cervix cancer HeLa and osteoblast-like MG-63 cells.

Growth in Hyper-Concentrated Sweet Whey Triggers Multi Stress Tolerance and Spray Drying Survival in BL23: From the Molecular Basis to New Perspectives for Sustainable Probiotic Production.

BL23 has a recognized probiotic potential, which includes immune modulation, protection toward induced colitis, toward induced colon cancer and toward dissemination of pathogens. In , as well as in other probiotics, both probiotic and technological abilities are highly dependent (1) on the substrate used to grow bacteria and (2) on the process used to dry and store this biomass. Production and storage of probiotics, at a reasonable financial and environmental cost, becomes a crucial challenge.

Extracellular Vesicles Elicit an Immunostimulatory Response on the Murine Mammary Gland.

is a major pathogen responsible for bovine mastitis, the most common and costly disease affecting dairy cattle. naturally releases extracellular vesicles (EVs) during its growth. EVs play an important role in the bacteria-bacteria and bacteria-host interactions and are notably considered as nanocarriers that deliver virulence factors to the host tissues.

Mutation of the Surface Layer Protein SlpB Has Pleiotropic Effects in the Probiotic CIRM-BIA 129.

is a beneficial Gram-positive bacterium, traditionally used as a cheese-ripening starter, and currently considered as an emerging probiotic. As an example, the CIRM-BIA 129 strain recently revealed promising immunomodulatory properties. Its consumption accordingly exerts healing effects in different animal models of colitis, suggesting a potent role in the context of inflammatory bowel diseases.

Physico-chemical characterization of dairy gel obtained by a proteolytic extract from Calotropis procera - A comparison with chymosin.

Chymosin is the major enzyme used in cheesemaking but latex enzymes are also used. The aim of this work was to characterize the composition and the structure of dairy gel obtained by an extract of Calotropis procera leaves in comparison with those obtained by chymosin. The biochemical and mineral compositions of the curds and the cheese yields obtained by using Calotropis procera extract or chymosin were relatively similar.

Contribution of sortase SrtA2 to Lactobacillus casei BL23 inhibition of Staphylococcus aureus internalization into bovine mammary epithelial cells.

Probiotics have been considered as a promising strategy to prevent various diseases in both humans and animals. This approach has gained interest in recent years as a potential means to control bovine mastitis. In a previous study, we found that several L.

Lipid droplets coated with milk fat globule membrane fragments: Microstructure and functional properties as a function of pH.

Processed lipid droplets coated by milk fat globule membrane (MFGM) material are of primary interest to mimic the specific functions provided by the fat globules in milk and dairy products. The objectives were to investigate, as a function of pH, the properties and microstructure of MFGM-coated lipid droplets prepared with an ingredient rich in MFGM containing polar lipids and proteins. The samples were prepared in water and in milk ultrafiltrate.

Pepsin diffusion in dairy gels depends on casein concentration and microstructure.

Fundamental knowledge of gastric digestion had only focused on acid diffusion from the gastric fluid, but no data are available for pepsin diffusion. Using fluorescence recovery after photobleaching technique, diffusion coefficients D of fluorescein isothiocyanate (FITC)-pepsin were measured in rennet gels across a range of casein concentrations allowing to form networks of protein aggregates with different structures. To investigate the microstructural parameters of native gels, electron microscopy image analysis were performed and qualitatively related to diffusion behavior of FITC-pepsin in these dairy gels.

Organization of lipids in milks, infant milk formulas and various dairy products: role of technological processes and potential impacts.

The microstructure of milk fat in processed dairy products is poorly known despite its importance in their functional, sensorial and nutritional properties. However, for the last 10 years, several research groups including our laboratory have significantly contributed to increasing knowledge on the organization of lipids in situ in dairy products. This paper provides an overview of recent advances on the organization of lipids in the milk fat globule membrane using microscopy techniques (mainly confocal microscopy and atomic force microscopy).

Spermatogonial stem cell quest: nanos2, marker of a subpopulation of undifferentiated A spermatogonia in trout testis.

Continuous or cyclic production of spermatozoa throughout life in adult male vertebrates depends on a subpopulation of undifferentiated germ cells acting as spermatogonial stem cells (SSCs). What makes these cells self-renew or differentiate is barely understood, in particular in nonmammalian species, including fish. In the highly seasonal rainbow trout, at the end of the annual spermatogenetic cycle, tubules of the spawning testis contain only spermatozoa, with the exception of scarce undifferentiated spermatogonia that remain on the tubular wall and that will support the next round of spermatogenesis.

Sex differentiation in an all-female (XX) rainbow trout population with a genetically governed masculinization phenotype.

Sex determination is known to be male heterogametic in the rainbow trout, Oncorhynchus mykiss; however, scattered observations that deviate from this rather strict genetic control have been reported. Here, we provide a detailed morphological and histological characterization of the gonadal differentiation and development (from 43 days postfertilization to 11 months of age) in an all-female (XX) population with a genetically governed masculinization phenotype. In comparison with control males and females, the gonadal differentiation in these animals was characterized by many perturbations, including significantly fewer germ cells.

Characterization of goldfish fin cells in culture: some evidence of an epithelial cell profile.

Comprehensive characterization of cultured cells in fish was little explored and cell origin is often deduced from morphological analogies with either epithelial of fibroblastic cells. This study aims to characterize cell origin in goldfish fin culture using morphological, immunochemical, and molecular approaches. Time lapse analysis revealed that cultured cell morphology changed within minutes.

Estrogen treatment up-regulates female genes but does not suppress all early testicular markers during rainbow trout male-to-female gonadal transdifferentiation.

In non-mammalian vertebrates, estrogens are key players in ovarian differentiation, but the mechanisms by which they act remain poorly understood. The present study on rainbow trout was designed to investigate whether estrogens trigger the female pathway by activating a group of early female genes (i.e.

Rainbow trout gonadal masculinization induced by inhibition of estrogen synthesis is more physiological than masculinization induced by androgen supplementation.

The present study was designed to obtain new insights into fish gonadal sex differentiation by comparing the effects of two different masculinizing treatments on some candidate gene expression profiles. Masculinization was induced in rainbow trout, Oncorhynchus mykiss, genetic all-female populations using either an active fish androgen (11betaAnd, 11beta-hydroxyandrostenedione) or an aromatase inhibitor (ATD, 1,4,6-androstatriene-3,17-dione). The expression profiles of 100 candidate genes were obtained by real-time RT-PCR, and 46 profiles displayed a significant differential expression between control populations (males and females) and ATD/11betaAnd-treated populations.

Trout gill cells in primary culture on solid and permeable supports.

Trout gill cells in primary culture on solid and permeable supports were compared. Cultures were carried out by directly seeding cells on each support after gill dissociation. Most of the cell types present in culture were similar, regardless of culture support (pavement cells, mucous cells (3-4%), but no mitochondria-rich cells).

Characterization of early molecular sex differentiation in rainbow trout, Oncorhynchus mykiss.

Early differentiation in rainbow trout gonads was investigated by expression profiling and in situ hybridization (ISH). Expression of cyp19a1 and fst in females and sox9a1 in males were sexually dimorphic between 32 to 35 days post-fertilization (dpf). After 35 dpf, the differentiation proceeded with sexually dimorphic profiles for sox9a2, dmrt1, cyp11b2.

Tilapia (Oreochromis niloticus) vitellogenins: development of homologous and heterologous ELISAs and analysis of vitellogenin pathway through the ovarian follicle.

Vitellogenin (VTG) of Oreochromis niloticus was again purified, due to the conflicting results found in the literature. Three purification processes have been used: electrophoresis and electro-elution, double chromatography (gel filtration and ion-exchange chromatography) and single ion-exchange chromatography. Using SDS-PAGE we confirmed in all cases the presence of two polypeptidic forms of plasma VTG of 130 kDa (VTG1) and 170 kDa (VTG2).

In situ hybridisation of a large repertoire of muscle-specific transcripts in fish larvae: the new superficial slow-twitch fibres exhibit characteristics of fast-twitch differentiation.

Much of the present information on muscle differentiation in fish concerns the early embryonic stages. To learn more about the maturation and the diversification of the fish myotomal fibres in later stages of ontogeny, we investigated, by means of in situ hybridisation, the developmental expression of a large repertoire of muscle-specific genes in trout larvae from hatching to yolk resorption. At hatching, transcripts for fast and slow muscle protein isoforms, namely myosins, tropomyosins, troponins and myosin binding protein C were present in the deep fast and the superficial slow areas of the myotome, respectively.

Muscle fiber differentiation in fish embryos as shown by in situ hybridization of a large repertoire of muscle-specific transcripts.

Skeletal muscles are composed of different fiber types, largely defined by differential expression of protein isoforms involved in myofibrillogenesis or metabolism. To learn more about the gene activations that underlie the differentiation and the diversification of embryonic fish myotomal fibers, we investigated the developmental expression of 25 muscle genes in trout embryos by in situ hybridization of muscle-specific transcripts. The earliest event of muscle differentiation, at approximately the 25-somite stage, was the expression of a variety of muscle-specific genes, including slow-twitch and fast-twitch muscle isoforms.

Expression patterns of collagen I (alpha1) encoding gene and muscle-specific genes reveal that the lateral domain of the fish somite forms a connective tissue surrounding the myotome.

Somites are repeated, epithelial structures that are derived from the unsegmented paraxial mesoderm located lateral to the notochord. In higher vertebrates, somites differentiate into a sclerotome that subsequently forms the vertebrae and the ribs and into a dermomyotome that gives rise to a myotome, from which arises the skeletal muscle, and to a dermatome, from which arises the dermis. Fish somites have been shown to produce a sclerotome and a myotome, but very little is known regarding their participation in the formation of connective tissues, especially at the junction between the epidermis and the myotome.

Analysis of cell-specificity and variegation of transgene expression driven by salmon prolactin promoter in stable lines of transgenic rainbow trout.

In order to identify the specificity and functionality of salmon prolactin (sPRL) promoter, transgenic rainbow trout carrying a construct comprising the 2.4 kb fragment of the 5' flanking region of Atlantic Chinook sPRL gene fused either to the reporter genes cat (sPRL-cat) or lacZ (sPRL-lacZ) were produced. sPRL-cat in transgenic F0 fish expressed strongly CAT only in the pituitary gland.

Differential expression of the two GH genes during embryonic development of rainbow trout Oncorhynchus mykiss in relation with the IGFs system.

The Growth hormone (GH)/insulin-like growth factor (IGF) system promotes embryonic growth in higher vertebrates. Such a system exists in salmonids, but exhibits an additional level of complexity resulting from a recent whole genome tetraploidisation. Thus, two nonallelic GH genes are present in the trout genome.

Type II iodothyronine deiodinase is preferentially expressed in rainbow trout (Oncorhynchus mykiss) liver and gonads.

It is well admitted that thyroid hormones (TH) play a role in the development of vertebrates. The major secretory product of the thyroid is a pro-hormone, T(4), which is activated in peripheral tissues by outer ring deiodination to T(3). We have isolated from rainbow trout testis, a full length cDNA encoding type II iodothyronine deiodinase (rtD2).