Effects of sub-lethal doses of nisin on the virulence of Salmonella enterica in Galleria mellonella larvae

Silva, Fernanda Pereira da; Fernandes, Kenner Morais; Freitas, Leonardo Luiz de; Cascardo, Renan de Souza; Bernardes, Rodrigo Cupertino; Oliveira, Leandro Licursi de; Martins, Gustavo Ferreira; Vanetti, Maria Cristina Dantas

doi:10.1016/j.resmic.2021.103836

Cited by 7 publications

(7 citation statements)

References 40 publications

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“…This conclusion is consistent with prior studies in the American cockroach which speculated that hemocytes limit infection of the hemolymph by S. Typhimurium (Klowden and Greenberg 1977). In contrast, in the model G. mellonella , proliferation of S. Typhimurium in the hemolymph and within hemocytes is pronounced (Viegas et al 2013, Luiz de Freitas et al 2021, Silva et al 2021). S. Typhimurium can also establish intracellular infection in Drosophila melanogaster hemocytes (Brandt et al 2004, Shinzawa et al 2009).…”

Section: Discussionmentioning

confidence: 86%

Survival of Salmonella Typhimurium in the hemolymph of the German cockroach vector is limited by both humoral immune factors and hemocytes but not by trehalose metabolism

Turner,

Van Hulzen,

Peta

et al. 2023

Journal of Medical Entomology

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The German cockroach (Blattella germanica) has been linked to transmission of Salmonella enterica serovar Typhimurium (S. Typhimurium), but infection dynamics within this vector are poorly characterized. Our recent work has focused on S. Typhimurium infection in the cockroach gut. However, microbial dissemination to the hemolymph is an essential aspect of many vector-borne pathogen transmission cycles and could potentially contribute to S. Typhimurium colonization of cockroaches. Therefore, the goal of this study was to examine the ability of S. Typhimurium to disseminate, survive, and proliferate in the hemolymph of cockroaches after oral infection. We detected only low numbers of bacteria in the hemolymph of a minority of insects (~26%) after oral infection. Further, S. Typhimurium was unable to survive overnight in cell-free hemolymph. Several hypotheses to explain the inability of S. Typhimurium to colonize hemolymph were tested. First, we investigated the ability of S. Typhimurium to metabolize trehalose, the primary sugar in hemolymph. S. Typhimurium grew efficiently in vitro using trehalose as a sole carbon source and mutant strains lacking trehalose metabolism genes exhibited no growth deficiencies in media mimicking the composition of hemolymph, suggesting that trehalose metabolism ability is not a factor involved in restricting survival in hemolymph. On the other hand, heat-inactivated cell-free hemolymph was permissive of S. Typhimurium growth, demonstrating that survival in hemolymph is limited specifically by heat-labile humoral factors. The involvement of cellular immune responses was also investigated and cockroach hemocytes in culture were observed to internalize S. Typhimurium within 1 h of exposure. Most hemocytes harbored few to no bacteria after 24 h, indicating that hemocyte responses are additionally involved in clearing infection from the hemolymph. However, dense intracellular clusters of S. Typhimurium were observed sporadically, suggesting a small subset of hemocytes may serve as reservoirs for bacterial replication. Together, our results reveal that a minute proportion of ingested S. Typhimurium is able to escape the cockroach gut and enter the hemolymph, but this systemic population is limited by both humoral effectors and hemocytes. Thus, we conclude that invasion of the hemolymph appears minimally important for colonization of the cockroach vector and that colonization of the gut is the main driver of vector-borne transmission. Our insight into the antimicrobial mechanisms of cockroach hemolymph also highlights the strong ability of these prevalent pests/vectors to cope with frequent infectious challenges in septic habitats.

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Section: Discussionmentioning

confidence: 86%

Survival of Salmonella Typhimurium in the hemolymph of the German cockroach vector is limited by both humoral immune factors and hemocytes but not by trehalose metabolism

Turner,

Van Hulzen,

Peta

et al. 2023

Journal of Medical Entomology

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“…In parallel, AMPs released in the physiological fluids can promote the recruitment of neutrophils at the infection site, thus activating the immunological cascade thus indirectly counteracting the infection [62,63]. In the specific case of nisin, even if its concentration is lower than the minimum inhibitory concentration (MIC), this molecule can still regulate the toxic activity of bacteria by downregulating the expression of the toxin-encoding genes [63][64][65].…”

Section: Characterization After the Release Testsmentioning

confidence: 99%

Functionalization of a chemically treated Ti6Al4V-ELI alloy with nisin for antibacterial purposes

Gobbo

Lallukka

Gamna

et al. 2023

Applied Surface Science

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“…The expression of peritrophic membrane protein-related genes BmCBP-02 , BmPM-41 , BmPM-43 , and BmCDA7, as well as the toll signaling pathway-related genes Bmcactus , Bmspatzle , and Bmrel , was significantly down-regulated in the gut of B. mori following exposure to phoxim, leading to B. mori’s susceptibility to E. cloacae [ 74 ]. Silva et al found that G. mellonella larval mortality and immune responses were significantly increased when inoculated with sub-inhibitory concentrations of nisin and S. enterica [ 75 ].…”

Section: Negative Effects Of Gut Microbes On the Hostmentioning

confidence: 99%

“…Some gut commensal bacteria may be transformed into pathogenic bacteria in the presence of dysregulated insect gut microbial homeostasis, such as S. marcescens , Pseudomonas protegens Ramette, and B. cereus , which can elicit host immune responses and disrupt gut microbial homeostasis, and thus pose a serious threat to insect health [ 80 , 81 , 82 ]. S. marcescens , a symbiotic bacteria in the mosquito gut, secretes a secreted protein called SmEnhancin to facilitate arbovirus infection [ 75 , 83 ]. Johnson et al found that Drosophila significantly increased the host’s susceptibility to B. bassiana after feeding on Pseudomonas protegens Ramette.…”

Section: Negative Effects Of Gut Microbes On the Hostmentioning

confidence: 99%

Research Progresses on the Function and Detection Methods of Insect Gut Microbes

Chang

et al. 2023

Microorganisms

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The insect gut is home to an extensive array of microbes that play a crucial role in the digestion and absorption of nutrients, as well as in the protection against pathogenic microorganisms. The variety of these gut microbes is impacted by factors such as age, diet, pesticides, antibiotics, sex, and caste. Increasing evidence indicates that disturbances in the gut microbiota can lead to compromised insect health, and that its diversity has a far-reaching impact on the host’s health. In recent years, the use of molecular biology techniques to conduct rapid, qualitative, and quantitative research on the host intestinal microbial diversity has become a major focus, thanks to the advancement of metagenomics and bioinformatics technologies. This paper reviews the main functions, influencing factors, and detection methods of insect gut microbes, in order to provide a reference and theoretical basis for better research utilization of gut microbes and management of harmful insects.

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Effects of sub-lethal doses of nisin on the virulence of Salmonella enterica in Galleria mellonella larvae

Cited by 7 publications

References 40 publications

Survival of Salmonella Typhimurium in the hemolymph of the German cockroach vector is limited by both humoral immune factors and hemocytes but not by trehalose metabolism

Survival of Salmonella Typhimurium in the hemolymph of the German cockroach vector is limited by both humoral immune factors and hemocytes but not by trehalose metabolism

Functionalization of a chemically treated Ti6Al4V-ELI alloy with nisin for antibacterial purposes

Research Progresses on the Function and Detection Methods of Insect Gut Microbes

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