Thein vitrobiocompatibility and macrophage phagocytosis of Mg17Al12phase in Mg-Al-Zn alloys

SummaryCollagen was incubated with cells or media fractions of mouse peritoneal macrophage cultures, and its aggregating effect on human platelets was tested. Incubation with lysates of cultured cells completely abolished the normal collagen-induced platelet aggregation, while incubation with media fractions only caused partial inhibition. The latter inhibition was more pronounced after macrophage phagocytosis of latex particles, while endocytosis of endotoxin had no effect.Corresponding macrophage cultures were also tested for specific collagenase activity, using 14C-glycine labelled collagen as substrate. Collagenase activity was found in the culture media fractions only, and the enzyme activity could be enhanced by endocytosis of latex as well as endotoxin.It appears that the effect of macrophage lysates and media on collagen-platelet interaction cannot be ascribed only to secretion of collagenase from macrophages.

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Effects of Cr and Zn on the interfacial microstructures of borides in Fe–Cr–B cast steels during hot-dipping in Al–Zn alloys

International Journal of Materials Research (formerly Zeitschrift fuer Metallkunde) ◽

10.3139/146.111742 ◽

2019 ◽

Author(s):

Xianman Zhang ◽

Weiping Chen ◽

Hongfeng Luo ◽

Shuang Li ◽

Teng Zhou

Keyword(s):

Cast Steels ◽

Zn Alloys

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Ab Initio Molecular Dynamics Simulation of the Amorphous Structure of Ca-Mg-Cu and Ca-Mg-Zn Alloys (Preprint)

10.21236/ada566094 ◽

2012 ◽

Author(s):

O. N. Senkov ◽

Y. Q. Cheng

Keyword(s):

Molecular Dynamics ◽

Molecular Dynamics Simulation ◽

Ab Initio ◽

Amorphous Structure ◽

Dynamics Simulation ◽

Ab Initio Molecular Dynamics ◽

Zn Alloys

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Thermodynamic, Kinetic, and Physical Properties of Ag-Al-Cu-Ni-Si-Zn Alloys

10.2172/1440721 ◽

2018 ◽

Author(s):

Patrice E. A. Turchi

Keyword(s):

Physical Properties ◽

Zn Alloys

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Modelling the thermodynamic data for hcp Zn and Cu–Zn alloys– an ab initio and calphad approach

Calphad ◽

10.1016/j.calphad.2021.102253 ◽

2021 ◽

Vol 72 ◽

pp. 102253

Author(s):

Alan Dinsdale ◽

Alexandra Khvan ◽

Ekaterina A. Smirnova ◽

Alena V. Ponomareva ◽

Igor A. Abrikosov

Keyword(s):

Ab Initio ◽

Thermodynamic Data ◽

Calphad Approach ◽

Zn Alloys

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The PTS Components in Klebsiella pneumoniae Affect Bacterial Capsular Polysaccharide Production and Macrophage Phagocytosis Resistance

Microorganisms ◽

10.3390/microorganisms9020335 ◽

2021 ◽

Vol 9 (2) ◽

pp. 335

Author(s):

Novaria Sari Dewi Panjaitan ◽

Yu-Tze Horng ◽

Chih-Ching Chien ◽

Hung-Chi Yang ◽

Ren-In You ◽

...

Keyword(s):

Survival Rate ◽

Klebsiella Pneumoniae ◽

Laser Scanning ◽

Bacterial Resistance ◽

Capsular Polysaccharide ◽

Laser Scanning Microscopy ◽

Confocal Laser ◽

Intracellular Bacteria ◽

Wild Type ◽

Macrophage Phagocytosis

Capsular polysaccharide (CPS) is a crucial virulence factor for Klebsiella pneumoniae infection. We demonstrated an association of CPS production with two phosphoenolpyruvate:carbohydrate phosphotransferase systems (PTSs). Deficiency of crr, encoding enzyme IIA of PTS, in K. pneumoniae enhanced the transcriptional activities of galF, wzi and gnd, which are in the cps gene cluster, leading to high CPS production. A crr mutant exhibited a higher survival rate in 1% hydrogen peroxide than the wild-type. The crr mutant showed less sensitivity to engulfment by macrophage (RAW 264.7) than the wild-type by observing the intracellular bacteria using confocal laser scanning microscopy (CLSM) and by calculating the colony-forming units (CFU) of intracellular bacteria. After long-term incubation, the survival rate of the intracellular crr mutant was higher than that of the wild-type. Deficiency of crr enhanced the transcriptional activities of etcABC which encodes another putative enzyme II complex of a PTS. Deletion of etcABC in the crr mutant reduced CPS production and the transcriptional activities of galF compared to those of the crr mutant. These results indicated that one PTS component, Crr, represses CPS production by repressing another PTS component, EtcABC, in K. pneumoniae. In addition, PTS plays a role in bacterial resistance to macrophage phagocytosis.

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Lactobacillus rhamnosus HDB1258 modulates gut microbiota-mediated immune response in mice with or without lipopolysaccharide-induced systemic inflammation

BMC Microbiology ◽

10.1186/s12866-021-02192-4 ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Sang-Kap Han ◽

Yeon-Jeong Shin ◽

Dong-Yeon Lee ◽

Kyung Min Kim ◽

Seo-Jin Yang ◽

...

Keyword(s):

Immune Response ◽

Gut Microbiota ◽

Oral Administration ◽

Systemic Inflammation ◽

Nk Cell ◽

Lactobacillus Rhamnosus ◽

Expression Ratio ◽

Macrophage Phagocytosis ◽

Tnf Α ◽

Gut Microbiota Composition

Abstract Background Gut microbiota closely communicate in the immune system to maintain a balanced immune homeostasis in the gastrointestinal tract of the host. Oral administration of probiotics modulates gut microbiota composition. In the present study, we isolated Lactobacillus rhamnosus HDB1258, which induced tumor necrosis factor (TNF)-α and interleukin (IL)-10 expression in macrophages, from the feces of breastfeeding infants and examined how HDB1258 could regulate the homeostatic immune response in mice with or without lipopolysaccharide (LPS)-induced systemic inflammation. Results Oral administration of HDB1258 significantly increased splenic NK cell cytotoxicity, peritoneal macrophage phagocytosis, splenic and colonic TNF-α expression, TNF-α to IL-10 expression ratio, and fecal IgA level in control mice, while Th1 and Treg cell differentiation was not affected in the spleen. However, HDB1258 treatment significantly suppressed peritoneal macrophage phagocytosis and blood prostaglandin E2 level in mice with LPS-induced systemic inflammation. Its treatment increased LPS-suppressed ratios of Treg to Th1 cell population, Foxp3 to T-bet expression, and IL-10 to TNF-α expression. Oral administration of HDB1258 significantly decreased LPS-induced colon shortening, myeloperoxidase activity and NF-κB+/CD11c+ cell population in the colon, while the ratio of IL-10 to TNF-α expression increased. Moreover, HDB1258 treatment shifted gut microbiota composition in mice with and without LPS-induced systemic inflammation: it increased the Cyanobacteria and PAC000664_g (belonging to Bacteroidetes) populations and reduced Deferribacteres and EU622763_s group (belonging to Bacteroidetes) populations. In particular, PAC001066_g and PAC001072_s populations were negatively correlated with the ratio of IL-10 to TNF-α expression in the colon, while the PAC001070_s group population was positively correlated. Conclusions Oral administered HDB1258 may enhance the immune response by activating innate immunity including to macrophage phagocytosis and NK cell cytotoxicity in the healthy host and suppress systemic inflammation in the host with inflammation by the modulation of gut microbiota and IL-10 to TNF-α expression ratio in immune cells.

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