scholarly journals Metabolites of bovine-associated non-aureus staphylococci influence expression of Staphylococcus aureus agr-related genes in vitro

2021 ◽  
Vol 52 (1) ◽  
Author(s):  
Bruno Toledo-Silva ◽  
Fernando Nogueira de Souza ◽  
Sofie Piepers ◽  
Kristien Mertens ◽  
Freddy Haesebrouck ◽  
...  
Keyword(s):  
Growth Inhibition ◽  
Virulence Genes ◽  
Culture Supernatant ◽  
Bovine Milk ◽  
Microbial Interactions ◽  
Proteinase K ◽  
In Vitro Growth ◽  
Isolation And Identification ◽  
And Control

AbstractCommunications via quorum sensing (QS) between non-aureus staphylococci (NAS) and Staphylococcus (S.) aureus in the bovine mammary gland remains largely unexplored. We determined whether 34 S. chromogenes, 11 S. epidermidis, and 14 S. simulans isolates originating from bovine milk samples and teat apices were able to regulate the QS of S. aureus, and if so, how in vitro growth inhibition of S. aureus by NAS, or NAS metabolites, or NAS cells themselves play a role in this process. In co-culture with S. aureus we observed that these 3 NAS species in general downregulated the expression of rnaIII, the effector molecule of the QS system, but this effect was more pronounced in S. chromogenes and S. simulans isolates than in S. epidermidis isolates. In vitro growth inhibition of S. aureus by NAS resulted in a small underestimation of the downregulating effect of NAS on rnaIII expression of S. aureus. Additionally, the culture supernatant of these NAS isolates and supernatant treated with proteinase K expressed greater regulatory activity over S. aureus virulence genes rnaIII, hla, and spa than washed NAS cells suspended in sterile water. These microbial interactions may influence S. aureus virulence and pathogenesis within the host. Isolation and identification of NAS metabolites affecting the QS system of S. aureus might help to develop alternative strategies for treatment and control of S. aureus mastitis.

scholarly journals Stage-dependent effect of deferoxamine on growth of Plasmodium falciparum in vitro

Blood ◽  
1990 ◽  
Vol 76 (6) ◽  
pp. 1250-1255 ◽  
Author(s):  
S Whitehead ◽  
TE Peto
Keyword(s):  
Plasmodium Falciparum ◽  
Growth Inhibition ◽  
Antimalarial Activity ◽  
Clinical Malaria ◽  
Inhibitory Effect ◽  
Parasite Development ◽  
And Control ◽  
Speed Of Onset

Abstract Deferoxamine (DF) has antimalarial activity that can be demonstrated in vitro and in vivo. This study is designed to examine the speed of onset and stage dependency of growth inhibition by DF and to determine whether its antimalarial activity is cytostatic or cytocidal. Growth inhibition was assessed by suppression of hypoxanthine incorporation and differences in morphologic appearance between treated and control parasites. Using synchronized in vitro cultures of Plasmodium falciparum, growth inhibition by DF was detected within a single parasite cycle. Ring and nonpigmented trophozoite stages were sensitive to the inhibitory effect of DF but cytostatic antimalarial activity was suggested by evidence of parasite recovery in later cycles. However, profound growth inhibition, with no evidence of subsequent recovery, occurred when pigmented trophozoites and early schizonts were exposed to DF. At this stage in parasite development, the activity of DF was cytocidal and furthermore, the critical period of exposure may be as short as 6 hours. These observations suggest that iron chelators may have a role in the treatment of clinical malaria.

scholarly journals ACTIVIDAD ANTAGÓNICA ENTRE BACTERIAS EPIBIÓTICAS AISLADAS DE ESPONJAS MARINAS DEL CARIBE COLOMBIANO Y SU RELACIÓN CON LA MACROEPIBIOSIS

2016 ◽  
Vol 38 (1) ◽  
Author(s):  
Jennyfer Mora Cristancho ◽  
Sven Zea ◽  
Diego L. Gil Agudelo
Keyword(s):  
Population Growth ◽  
Growth Inhibition ◽  
Bacterial Communities ◽  
Growth Regulation ◽  
In Vitro Growth ◽  
Bacterial Strains ◽  
Total Percentage ◽  
Potential Interactions ◽  
Antagonistic Interactions

Surfaces submerged in the sea are densely colonized by bacteria, and inter-specic interactions such as growth inhibition are important determinants of the development of bacterial communities, as well as of later phases of macrofouling. To determine the potential interactions among biolm bacteria from sponges we carried out in vitro growth inhibition tests between bacterial strains isolated from surfaces with various degrees of macrofouling, from the sponges Aplysina insularis (clean), Aplysina lacunosa (fouled), and from the calcareous surface of the bivalve mollusk Donax sp. The total percentage of antagonistic interactions among these strains was 64 %; strains isolated from clean surfaces inhibited the growth of strains from well-colonized surfaces in a 1:1 ratio. Strains from clean surfaces had a higher frequency of antagonistic interactions. We propose bacterial antagonistic interaction as a possible mechanism of population growth regulation and, consequently, of the development of subsequent phases of macrofouling.

In silico evaluation and in vitro growth inhibition of Plasmodium falciparum by natural amides and synthetic analogs

2020 ◽  
Vol 119 (6) ◽  
pp. 1879-1887
Author(s):  
Minelly Azevedo da Silva ◽  
Márcia Paranho Veloso ◽  
Kassius de Souza Reis ◽  
Guilherme de Matos Passarini ◽  
Ana Paula de Azevedo dos Santos ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Growth Inhibition ◽  
In Silico ◽  
In Vitro Growth ◽  
Synthetic Analogs

Effects of granulocyte-macrophage colony-stimulating factor on in vitro growth of human solid tumors.

1989 ◽  
Vol 7 (9) ◽  
pp. 1346-1350 ◽  
Author(s):  
S E Salmon ◽  
R Liu
Keyword(s):  
Growth Inhibition ◽  
Solid Tumors ◽  
Primary Role ◽  
In Vitro Growth ◽  
Colony Stimulating Factor ◽  
Gm Csf ◽  
Macrophage Colony Stimulating Factor ◽  
Macrophage Colony ◽  
Stimulating Factor

Solid tumor biopsies from 33 patients were tested in vitro to evaluate the growth modulatory effects of recombinant human granulocyte-macrophage colony-stimulating factor (GM-CSF). In 29 of 33 studies (88%), addition of GM-CSF either had no effect on in vitro growth, or induced growth inhibition. While significant growth inhibition was observed in 10 studies, marked inhibition was only observed in three studies. However, all dose-response curves were usually flat, suggesting indirect effects. Moderate growth stimulation was observed in four instances, which may have been due to residual granulocyte-macrophage progenitors within the biopsies. We conclude that GM-CSF has little or no growth-modulatory effect on most nonhematopoietic neoplasms. The primary role of GM-CSF in patients with solid tumors appears to be in prevention or reversal of myelosuppression associated with therapy. Thus, while GM-CSF seems unlikely to have a role in monotherapy of cancer, it is also unlikely to have its utility compromised by enhancement of tumor growth.

Comparative molecular field analysis of in vitro growth inhibition of L1210 and HCT-8 cells by some pyrazoloacridines

1993 ◽  
Vol 36 (23) ◽  
pp. 3511-3516 ◽  
Author(s):  
Jerome P. Horwitz ◽  
Irina Massova ◽  
Thomas E. Wiese ◽  
Antoinette J. Wozniak ◽  
Thomas H. Corbett ◽  
...  
Keyword(s):  
Growth Inhibition ◽  
Field Analysis ◽  
Molecular Field ◽  
In Vitro Growth ◽  
Comparative Molecular Field Analysis ◽  
Molecular Field Analysis

Sustained release of PI3K inhibitor from PHA nanoparticles and in vitro growth inhibition of cancer cell lines

2011 ◽  
Vol 89 (5) ◽  
pp. 1423-1433 ◽  
Author(s):  
Xiao-Yun Lu ◽  
Elisa Ciraolo ◽  
Rachele Stefenia ◽  
Guo-Qiang Chen ◽  
Yali Zhang ◽  
...  
Keyword(s):  
Sustained Release ◽  
Growth Inhibition ◽  
Cell Lines ◽  
Cancer Cell ◽  
Cancer Cell Lines ◽  
Pi3k Inhibitor ◽  
In Vitro Growth

scholarly journals Human-human hybridomas secreting monoclonal antibodies to the Mr 195,000 Plasmodium falciparum blood stage antigen.

1986 ◽  
Vol 163 (1) ◽  
pp. 179-188 ◽  
Author(s):  
R Schmidt-Ullrich ◽  
J Brown ◽  
H Whittle ◽  
P S Lin
Keyword(s):  
Plasmodium Falciparum ◽  
Growth Inhibition ◽  
Protective Immunity ◽  
Lymphoblastoid Cell Line ◽  
In Vitro Growth ◽  
Human Lymphoblastoid Cell ◽  
Immune Precipitation ◽  
Human Lymphoblastoid Cell Line ◽  
Donor Lymphocytes

Using the human lymphoblastoid cell line, GM 4672, and PBL of Gambian adults immune to Plasmodium falciparum (Pf) malaria, we have produced human-human hybridomas and selected those that produce mAb against Pf antigens. The fusion frequency, using PWM-stimulated donor lymphocytes was between 6.8 X 10(-5) and 1.5 X 10(-6). Using immune fluorescence, immune precipitation, and Pf in vitro growth inhibition, we cloned four hybridomas that reacted with the Pf Mr 195,000 schizont/merozoite protein. The differences in proteins immune precipitated and in growth inhibition indicate that, during development of protective immunity against Pf malaria, a spectrum of antibodies is produced reacting with different epitopes on the same antigen. Only a portion of these antibodies exhibits biological activity, suggesting that the recognition of certain epitopes is required for the development of a protective immune response.

Sign in / Sign up

Export Citation Format

Share Document