Analysis of Virulence of Clinical Isolates ofSalmonella enteritidis In Vivo and In Vitro

ABSTRACT Salmonella enterica serotype Enteritidis (S. enteritidis) is a major food-borne pathogen, and its incidence among all Salmonella serotypes has increased dramatically in the last two decades. To study the virulence characteristics of clinical isolates of S. enteritidis, we determined the 50% lethal doses (LD50) in mice of isolates of two major phage types (4 and 8). Isolates of both phage types showed a wide range of LD50 after oral inoculation, varying from under 102 organisms to over 108 organisms. No significant difference in LD50 was observed between the phage types. These observations indicated that clinical isolates ofS. enteritidis are highly heterogeneous in their ability to cause death in mice. We compared the LD50s of these isolates to the results observed from in vitro pathogenicity assays. We also analyzed these isolates for recognized Salmonellavirulence loci (spv, sodCI, sopE, and sef). The in vitro phenotypes of the isolates showed no obvious correlation with their LD50 in any given assay, and the virulence genes tested were present in all isolates. However, the isolate with the lowest LD50 (isolate 97A 2472) was resistant to acidified sodium nitrite (ASN). Moreover, the most acid-susceptible, macrophage-susceptible, and ASN-susceptible isolates were attenuated for virulence in mice. These results, based on extensive analysis of clinical isolates of S. enteritidis, demonstrate the complex nature of Salmonella pathogenesis in mice. Our results also indicate the limitation of in vitro assays in predicting in vivo virulence.

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Probiotic and Functional Properties of Limosilactobacillus reuteri INIA P572

Nutrients ◽

10.3390/nu13061860 ◽

2021 ◽

Vol 13 (6) ◽

pp. 1860

Author(s):

Patricia Diez-Echave ◽

Izaskun Martín-Cabrejas ◽

José Garrido-Mesa ◽

Susana Langa ◽

Teresa Vezza ◽

...

Keyword(s):

In Vitro Assays ◽

Immunomodulatory Activity ◽

Probiotic Properties ◽

Protective Effects ◽

Mice Model ◽

In Vivo Models ◽

Food Borne ◽

Gastrointestinal Conditions

Limosilactobacillus reuteri INIA P572 is a strain able to produce the antimicrobial compound reuterin in dairy products, exhibiting a protective effect against some food-borne pathogens. In this study, we investigated some probiotic properties of this strain such as resistance to gastrointestinal passage or to colonic conditions, reuterin production in a colonic environment, and immunomodulatory activity, using different in vitro and in vivo models. The results showed a high resistance of this strain to gastrointestinal conditions, as well as capacity to grow and produce reuterin in a human colonic model. Although the in vitro assays using the RAW 264.7 macrophage cell line did not demonstrate direct immunomodulatory properties, the in vivo assays using a Dextran Sulphate Sodium (DSS)-induced colitic mice model showed clear immunomodulatory and protective effects of this strain.

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Cleaved CD31 as a target for in vivo molecular imaging of inflammation

Scientific Reports ◽

10.1038/s41598-019-56163-x ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 1

Author(s):

Jonathan Vigne ◽

Sylvie Bay ◽

Rachida Aid-Launais ◽

Guillaume Pariscoat ◽

Guillaume Rucher ◽

...

Keyword(s):

Molecular Imaging ◽

Molecular Form ◽

Positive Control ◽

Negative Control ◽

Stability Study ◽

Biodistribution Studies ◽

Wide Range ◽

Significant Difference

AbstractThere is a need for new targets to specifically localize inflammatory foci, usable in a wide range of organs. Here, we hypothesized that the cleaved molecular form of CD31 is a suitable target for molecular imaging of inflammation. We evaluated a bioconjugate of D-P8RI, a synthetic peptide that binds all cells with cleaved CD31, in an experimental rat model of sterile acute inflammation. Male Wistar rats were injected with turpentine oil into the gastrocnemius muscle two days before 99mTc-HYNIC-D-P8RI (or its analogue with L-Proline) SPECT/CT or [18F]FDG PET/MRI. Biodistribution, stability study, histology, imaging and autoradiography of 99mTc-HYNIC-D-P8RI were further performed. Biodistribution studies revealed rapid elimination of 99mTc-HYNIC-D-P8RI through renal excretion with almost no uptake from most organs and excellent in vitro and in vivo stability were observed. SPECT/CT imaging showed a significant higher 99mTc-HYNIC-D-P8RI uptake compared with its analogue with L-Proline (negative control) and no significant difference compared with [18F]FDG (positive control). Moreover, autoradiography and histology revealed a co-localization between 99mTc-HYNIC-D-P8RI uptake and inflammatory cell infiltration. 99mTc-HYNIC-D-P8RI constitutes a new tool for the detection and localization of inflammatory sites. Our work suggests that targeting cleaved CD31 is an attractive strategy for the specific in vivo imaging of inflammatory processes.

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Development and population dynamics of Steinernema yirgalemense (Rhabditida: Steinernematidae) and growth characteristics of its associated Xenorhabdusindica symbiont in liquid culture

Journal of Helminthology ◽

10.1017/s0022149x15000450 ◽

2015 ◽

Vol 90 (3) ◽

pp. 364-371 ◽

Cited By ~ 12

Author(s):

T. Ferreira ◽

M.F. Addison ◽

A.P. Malan

Keyword(s):

Population Density ◽

Liquid Culture ◽

Commercial Application ◽

Adult Density ◽

Developmental Phase ◽

Male Density ◽

Wide Range ◽

Significant Difference

AbstractEntomopathogenic nematodes have become a valuable addition to the range of biological control agents available for insect control. An endemic nematode, Steinernemayirgalemense, has been found to be effective against a wide range of key insect pests. The next step would be the mass production this nematode for commercial application. This requires the establishment of monoxenic cultures of both the nematode and the symbiotic bacterium Xenorhabdus indica. First-stage juveniles of S. yirgalemense were obtained from eggs, while X. indica was isolated from nematode-infected wax moth larvae. The population density of the various life stages of S. yirgalemense during the developmental phase in liquid culture was determined. The recovery of infective juveniles (IJs) to the third-stage feeding juveniles, was 67 ± 10%, reaching a maximum population density of 75,000 IJs ml− 1 on day 13 after inoculation. Adult density increased after 8 days, with the maximum female density being 4600 ml− 1 on day 15, whereas the maximum male density was 4300 ml− 1 on day 12. Growth curves for X. indica showed that the exponential phase was reached 15 h after inoculation to the liquid medium. The stationary phase was reached after 42 h, with an average of 51 × 107 colony-forming units ml− 1. Virulence tests showed a significant difference in insect mortality between in vitro- and in vivo-produced nematodes. The success obtained with the production of S. yirgalemense in liquid culture can serve as the first step in the optimizing and upscaling of the commercial production of nematodes in fermenters.

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In vitro and in vivo toxicity of fungicides and biofungicides for the control of verticillium and fusarium wilt of pepper

Pesticidi i fitomedicina ◽

10.2298/pif2101023m ◽

2021 ◽

Vol 36 (1) ◽

pp. 23-34

Author(s):

Milica Mihajlovic ◽

Emil Rekanovic ◽

Jovana Hrustic ◽

Mila Grahovac ◽

Brankica Tanovic

Keyword(s):

Antifungal Activity ◽

Verticillium Dahliae ◽

Antagonistic Activity ◽

In Vitro Assays ◽

Thiophanate Methyl ◽

Significant Difference ◽

By Products ◽

Pepper Plants

A survey of in vitro and in vivo sensitivity of Verticillium dahliae and Fusarium oxysporum to several commercial fungicides and biofungicides was undertaken. In in vitro assays, the tested isolate of V. dahliae proved to be very sensitive to difenoconazole (EC50 = 0.02 mg/l). However, under greenhouse conditions, the highest efficacy in V. dahliae control on inoculated pepper plants was recorded for a product based on thiophanate-methyl (83.10% compared to control). Among the tested fungicides, the lowest efficacy was recorded for a product based on azoxystrobin (23.10 %) with no significant difference compared to control (p > 0.05). In in vitro assays, the tested F. oxysporum isolate was the most sensitive to prochloraz (EC50 = 0.07 mg/l) and the least sensitive to fluopyram (EC50 = 1075.01 mg/l). In in vivo assay, the highest efficacy was achieved by products based on captan (95.60%), and the lowest by a product based on thiophanate-methyl (54.40%). Antagonistic activity of the bacterium B. subtilis under laboratory conditions was not satisfying. Also, the antifungal activity and spectrum of a tested product based on tee tree oil was not efficient in suppressing pepper wilting caused by V. dahliae and F. oxysporum.

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Heterogeneity among Isolates Reveals that Fitness in Low Oxygen Correlates withAspergillus fumigatusVirulence

mBio ◽

10.1128/mbio.01515-16 ◽

2016 ◽

Vol 7 (5) ◽

Cited By ~ 57

Author(s):

Caitlin H. Kowalski ◽

Sarah R. Beattie ◽

Kevin K. Fuller ◽

Elizabeth A. McGurk ◽

Yi-Wei Tang ◽

...

Keyword(s):

Aspergillus Fumigatus ◽

Experimental Evolution ◽

Invasive Pulmonary Aspergillosis ◽

Clinical Isolates ◽

Low Oxygen ◽

Single Strain ◽

Hypoxia Exposure ◽

Significant Difference

ABSTRACTPrevious work has shown that environmental and clinical isolates ofAspergillus fumigatusrepresent a diverse population that occupies a variety of niches, has extensive genetic diversity, and exhibits virulence heterogeneity in a number of animal models of invasive pulmonary aspergillosis (IPA). However, mechanisms explaining differences in virulence amongA. fumigatusisolates remain enigmatic. Here, we report a significant difference in virulence of two common lab strains, CEA10 and AF293, in the murine triamcinolone immunosuppression model of IPA, in which we previously identified severe low oxygen microenvironments surrounding fungal lesions. Therefore, we hypothesize that the ability to thrive within these lesions of low oxygen promotes virulence ofA. fumigatusin this model. To test this hypothesis, we performedin vitrofitness andin vivovirulence analyses in the triamcinolone murine model of IPA with 14 environmental and clinical isolates ofA. fumigatus. Among these isolates, we observed a strong correlation between fitness in low oxygenin vitroand virulence. In further support of our hypothesis, experimental evolution of AF293, a strain that exhibits reduced fitness in low oxygen and reduced virulence in the triamcinolone model of IPA, results in a strain (EVOL20) that has increased hypoxia fitness and a corresponding increase in virulence. Thus, the ability to thrive in low oxygen correlates with virulence ofA. fumigatusisolates in the context of steroid-mediated murine immunosuppression.IMPORTANCEAspergillus fumigatusoccupies multiple environmental niches, likely contributing to the genotypic and phenotypic heterogeneity among isolates. Despite reports of virulence heterogeneity, pathogenesis studies often utilize a single strain for the identification and characterization of virulence and immunity factors. Here, we describe significant variation betweenA. fumigatusisolates in hypoxia fitness and virulence, highlighting the advantage of including multiple strains in future studies. We also illustrate that hypoxia fitness correlates strongly with increased virulence exclusively in the nonleukopenic murine triamcinolone immunosuppression model of IPA. Through an experimental evolution experiment, we observe that chronic hypoxia exposure results in increased virulence ofA. fumigatus. We describe here the first observation of a model-specific virulence phenotype correlative within vitrofitness in hypoxia and pave the way for identification of hypoxia-mediated mechanisms of virulence in the fungal pathogenA. fumigatus.

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Regulatory Perspective on in Vitro Assays as Predictors of Phototoxicity and Photo Co-Carcinogenicity

International Journal of Toxicology ◽

10.1080/109158198226080 ◽

1998 ◽

Vol 17 (5) ◽

pp. 571-575 ◽

Cited By ~ 1

Author(s):

Amy L. Ellis

Keyword(s):

Mammalian Cells ◽

Hairless Mouse ◽

In Vitro Assays ◽

In Vitro Tests ◽

Drug Products ◽

Drug Classes ◽

Wide Range ◽

Regulatory Perspective

Drugs from a variety of chemical classes used for a wide range of therapeutic indications can be photosensitizers in humans. Several drugs are phototoxic in animal models as well; there are no nonclinical data for many. In vitro tests have been developed as predictors of phototoxicity and although they have been used as screens, none have replaced the in vivo tests done in rodents (usually mice or guinea pigs) since these have been good predictors of clinical phototoxicity. Some phototoxic drug classes are co-carcinogens with ultraviolet radiation (UVA and/or UVB) in hairless mice, specifically psoralens, retinoids, and fluo-roquinolones. Treatment with 8-methoxypsoralen and ultraviolet A radiation for psoriasis is also carcinogenic in humans. It has been suggested that in vitro photogenotoxicity assays using microorganisms or mammalian cells may be predictive of photo co-carcinogenicity. Some attractions of these in vitro assays, compared to the hairless mouse photo co-carcinogenicity assay, are their generally shorter duration and lower cost as well as reducing the number of animals used in research. Currently, personnel at the Food and Drug Administration (FDA) are examining the available data on phototoxicity, photogenotoxicity, and photo co-carcinogenicity to determine how this information can best be used toregulate and label drug products, and considering which assays should be recommended under specific circumstances.

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Natural Variability in S-Adenosylmethionine (SAM)-Dependent Riboswitches: S-Box Elements in Bacillus subtilis Exhibit Differential Sensitivity to SAM In Vivo and In Vitro

Journal of Bacteriology ◽

10.1128/jb.01034-07 ◽

2007 ◽

Vol 190 (3) ◽

pp. 823-833 ◽

Cited By ~ 73

Author(s):

Jerneja Tomšič ◽

Brooke A. McDaniel ◽

Frank J. Grundy ◽

Tina M. Henkin

Keyword(s):

Bacillus Subtilis ◽

Structural Rearrangement ◽

Natural Variability ◽

Differential Sensitivity ◽

In Vitro Assays ◽

Leader Region ◽

Structural Elements ◽

Wide Range

ABSTRACT Riboswitches are regulatory systems in which changes in structural elements in the 5′ region of the nascent RNA transcript (the “leader region”) control expression of the downstream coding sequence in response to a regulatory signal in the absence of a trans-acting protein factor. The S-box riboswitch, found primarily in low-G+C gram-positive bacteria, is the paradigm for riboswitches that sense S-adenosylmethionine (SAM). Genes in the S-box family are involved in methionine metabolism, and their expression is induced in response to starvation for methionine. S-box genes exhibit conserved primary sequence and secondary structural elements in their leader regions. We previously demonstrated that SAM binds directly to S-box leader RNA, causing a structural rearrangement that results in premature termination of transcription at S-box leader region terminators. S-box genes have a variety of physiological roles, and natural variability in S-box structure and regulatory response could provide additional insight into the role of conserved S-box leader elements in SAM-directed transcription termination. In the current study, in vivo and in vitro assays were employed to analyze the differential regulation of S-box genes in response to SAM. A wide range of responses to SAM were observed for the 11 S-box-regulated transcriptional units in Bacillus subtilis, demonstrating that S-box riboswitches can be calibrated to different physiological requirements.

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In Vitro and In Vivo Assessment of the Efficacy of Bromoageliferin, an Alkaloid Isolated from the Sponge Agelas dilatata, against Pseudomonas aeruginosa

Marine Drugs ◽

10.3390/md18060326 ◽

2020 ◽

Vol 18 (6) ◽

pp. 326

Author(s):

Dawrin Pech-Puch ◽

Mar Pérez-Povedano ◽

Marta Martinez-Guitian ◽

Cristina Lasarte-Monterrubio ◽

Juan Carlos Vázquez-Ucha ◽

...

Keyword(s):

Pseudomonas Aeruginosa ◽

Carboxylic Acid ◽

Galleria Mellonella ◽

Biological Activities ◽

Marine Sponges ◽

In Vitro Assays ◽

Significant Activity ◽

Wide Range

The pyrrole-imidazoles, a group of alkaloids commonly found in marine sponges belonging to the genus Agelas, display a wide range of biological activities. Herein, we report the first chemical study of the secondary metabolites of the sponge A. dilatata from the coastal area of the Yucatan Peninsula (Mexico). In this study, we isolated eight known alkaloids from an organic extract of the sponge. We used NMR and MS analysis and comparison with existing databases to characterize the alkaloids: ageliferin (1), bromoageliferin (2), dibromoageliferin (3), sceptrin (4), nakamuric acid (5), 4-bromo-1H-pyrrole-2-carboxylic acid (6), 4,5-dibromopyrrole-2-carboxylic acid (7) and 3,7-dimethylisoguanine (8). We also evaluated, for the first time, the activity of these alkaloids against the most problematic multidrug-resistant (MDR) pathogens, i.e., the Gram-negative bacteria Pseudomonas aeruginosa, Klebsiella pneumoniae and Acinetobacter baumannii. Bromoageliferin (2) displayed significant activity against P. aeruginosa. Comparison of the antibacterial activity of ageliferins 1–3 (of similar structure) against P. aeruginosa revealed some relationship between structure and activity. Furthermore, in in vitro assays, 2 inhibited growth and biofilm production in clinical strains of P. aeruginosa. Moreover, 2 increased the survival time in an in vivo Galleria mellonella model of infection. The findings confirm bromoageliferin (2) as a potential lead for designing new antibacterial drugs.

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Intestinal absorption of linoleic acid in experimental renal failure

British Journal Of Nutrition ◽

10.1079/bjn19910048 ◽

1991 ◽

Vol 66 (3) ◽

pp. 467-477

Author(s):

M. V. Pahl ◽

A. Barbari ◽

N. D. Vaziri ◽

D. Hollander ◽

M. Yazdani ◽

...

Keyword(s):

Renal Failure ◽

Linoleic Acid ◽

Water Layer ◽

Short Term ◽

Unstirred Water Layer ◽

Wide Range ◽

Significant Difference

Linoleic acid (LA) transport in rats with experimental short-term and long-term renal failure (RF) was compared with that of sham-operated normal animals on liberal food intake and pair-fed animals. The perfusions in vivo and incubations in vitro were conducted using a micellar solution containing a wide range of LA concentrations. Both absorption in vivo and uptake in vitro of LA were significantly reduced in animals with short-term RF. Lipid extraction and separation by thin-layer chromatography revealed a marked LA trapping as trilinolein (TL) in the perfused intestinal tissue in the short-term RF group. The esterification process, as defined by the rate of LA incorporation into TL, was moderately reduced in short-term RF animals. The thickness of the unstirred water layer showed no significant difference among the groups studied. In contrast, animals with long-term RF exhibited normal absorption of LA in vivo at all concentrations tested. In conclusion, LA absorption is reduced in short-term RF and restored in long-term RF. Several steps including LA transport into and TL transport out of the enterocyte and the esterification process were impaired in short-term RF. These changes are not due to alteration in the unstirred water layer, anorexia, weight loss or a rapid effect of uraemic chemical environment or circulatory factors.

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Mass Spectrometry-Based Zebrafish Toxicometabolomics: A Review of Analytical and Data Quality Challenges

Metabolites ◽

10.3390/metabo11090635 ◽

2021 ◽

Vol 11 (9) ◽

pp. 635

Author(s):

Katyeny Manuela da Silva ◽

Elias Iturrospe ◽

Chloe Bars ◽

Dries Knapen ◽

Steven Van Cruchten ◽

...

Keyword(s):

Mass Spectrometry ◽

Chemical Exposure ◽

Research Field ◽

In Vivo Studies ◽

In Vitro Assays ◽

Special Focus ◽

Zebrafish Model ◽

Wide Range

Metabolomics has achieved great progress over the last 20 years, and it is currently considered a mature research field. As a result, the number of applications in toxicology, biomarker, and drug discovery has also increased. Toxicometabolomics has emerged as a powerful strategy to provide complementary information to study molecular-level toxic effects, which can be combined with a wide range of toxicological assessments and models. The zebrafish model has gained importance in recent decades as a bridging tool between in vitro assays and mammalian in vivo studies in the field of toxicology. Furthermore, as this vertebrate model is a low-cost system and features highly conserved metabolic pathways found in humans and mammalian models, it is a promising tool for toxicometabolomics. This short review aims to introduce zebrafish researchers interested in understanding the effects of chemical exposure using metabolomics to the challenges and possibilities of the field, with a special focus on toxicometabolomics-based mass spectrometry. The overall goal is to provide insights into analytical strategies to generate and identify high-quality metabolomic experiments focusing on quality management systems (QMS) and the importance of data reporting and sharing.

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