scholarly journals Alternative bacteriophage life cycles: the carrier state of Campylobacter jejuni

Open Biology ◽  
2014 ◽  
Vol 4 (3) ◽  
pp. 130200 ◽  
Author(s):  
Patcharin Siringan ◽  
Phillippa L. Connerton ◽  
Nicola J. Cummings ◽  
Ian F. Connerton
Keyword(s):  
Campylobacter Jejuni ◽  
Pathogenic Bacteria ◽  
Carrier State ◽  
Life Cycles ◽  
Enteric Disease ◽  
New Host ◽  
Complex Life Cycles ◽  
Phenotypic Changes ◽  
Poultry Products ◽  
New Hosts

Members of the genus Campylobacter are frequently responsible for human enteric disease, often through consumption of contaminated poultry products. Bacteriophages are viruses that have the potential to control pathogenic bacteria, but understanding their complex life cycles is key to their successful exploitation. Treatment of Campylobacter jejuni biofilms with bacteriophages led to the discovery that phages had established a relationship with their hosts typical of the carrier state life cycle (CSLC), where bacteria and bacteriophages remain associated in equilibrium. Significant phenotypic changes include improved aerotolerance under nutrient-limited conditions that would confer an advantage to survive in extra-intestinal environments, but a lack in motility eliminated their ability to colonize chickens. Under these circumstances, phages can remain associated with a compatible host and continue to produce free virions to prospect for new hosts. Moreover, we demonstrate that CSLC host bacteria can act as expendable vehicles for the delivery of bacteriophages to new host bacteria within pre-colonized chickens. The CSLC represents an important phase in the ecology of Campylobacter bacteriophage.

Autonomy and integration in complex parasite life cycles

Parasitology ◽  
2016 ◽  
Vol 143 (14) ◽  
pp. 1824-1846 ◽  
Author(s):  
DANIEL P. BENESH
Keyword(s):  
Life Cycle ◽  
Holistic Approach ◽  
Life Cycles ◽  
Complex Life Cycle ◽  
Functional Specialization ◽  
Life Stages ◽  
Free Living ◽  
New Host ◽  
Complex Life Cycles ◽  
Life Cycle Stages

SUMMARYComplex life cycles are common in free-living and parasitic organisms alike. The adaptive decoupling hypothesis postulates that separate life cycle stages have a degree of developmental and genetic autonomy, allowing them to be independently optimized for dissimilar, competing tasks. That is, complex life cycles evolved to facilitate functional specialization. Here, I review the connections between the different stages in parasite life cycles. I first examine evolutionary connections between life stages, such as the genetic coupling of parasite performance in consecutive hosts, the interspecific correlations between traits expressed in different hosts, and the developmental and functional obstacles to stage loss. Then, I evaluate how environmental factors link life stages through carryover effects, where stressful larval conditions impact parasites even after transmission to a new host. There is evidence for both autonomy and integration across stages, so the relevant question becomes how integrated are parasite life cycles and through what mechanisms? By highlighting how genetics, development, selection and the environment can lead to interdependencies among successive life stages, I wish to promote a holistic approach to studying complex life cycle parasites and emphasize that what happens in one stage is potentially highly relevant for later stages.

The diversity and natural history of parasites

2021 ◽  
pp. 19-50
Author(s):  
Paul Schmid-Hempel
Keyword(s):  
Life Cycle ◽  
Natural History ◽  
Food Chain ◽  
Life Cycles ◽  
Growth Phases ◽  
New Host ◽  
Complex Life Cycles ◽  
Parasitic Species ◽  
Parasitic Lifestyle ◽  
History Of

Parasites are more numerous than non-parasitic species and have evolved in virtually all groups of organisms, such as viruses, prokaryotes (bacteria), protozoa, fungi, nematodes, flatworms, acantocephalans, annelids, crustaceans, and arthropods (crustacea, mites, ticks, insects). These groups have adapted to the parasitic lifestyle in very many ways. Evolution towards parasitism has also followed different routes. Initial steps such as phoresy, followed by later consumption of the transport host, are plausible evolutionary routes. Alternatively, formerly free-living forms have become commensals before evolving parasitism. Complex life cycles with several hosts evolved by scenarios such as upward (adding a new host upwards in the food chain), downward, or lateral incorporation, driven by the advantage of extending growth phases within hosts and increasing fecundity. Examples are digenea; other parasites have added vectors to their life cycle.

scholarly journals Sexual Development in Non-Human Parasitic Apicomplexa: Just Biology or Targets for Control?

Animals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 2891
Author(s):  
Teresa Cruz-Bustos ◽  
Anna Sophia Feix ◽  
Bärbel Ruttkowski ◽  
Anja Joachim
Keyword(s):  
Sexual Reproduction ◽  
Sexual Development ◽  
Current Knowledge ◽  
Life Cycles ◽  
Complex Life Cycles ◽  
Transmission Blocking ◽  
New Hosts ◽  
Sexual Stages ◽  
New Generation ◽  
Effective Transmission

The phylum Apicomplexa is a major group of protozoan parasites including gregarines, coccidia, haemogregarines, haemosporidia and piroplasms, with more than 6000 named species. Three of these subgroups, the coccidia, hemosporidia, and piroplasms, contain parasites that cause important diseases of humans and animals worldwide. All of them have complex life cycles involving a switch between asexual and sexual reproduction, which is key to their development. Fertilization (i.e., fusion of female and male cells) results in the formation of a zygote that undergoes meiosis, forming a new generation of asexual stages. In eukaryotes, sexual reproduction is the predominant mode of recombination and segregation of DNA. Sex is well documented in many protist groups, and together with meiosis, is frequently linked with transmission to new hosts. Apicomplexan sexual stages constitute a bottleneck in the life cycle of these parasites, as they are obligatory for the development of new transmissible stages. Consequently, the sexual stages represent attractive targets for vaccination. Detailed understanding of apicomplexan sexual biology will pave the way for the design and implementation of effective transmission-blocking strategies for parasite control. This article reviews the current knowledge on the sexual development of Apicomplexa and the progress in transmission-blocking vaccines for their control, their advantages and limitations and outstanding questions for the future.

scholarly journals Antimicrobial Efficacy and Spectrum of Phosphorous-Fluorine Co-Doped TiO2 Nanoparticles on the Foodborne Pathogenic Bacteria Campylobacter jejuni, Salmonella Typhimurium, Enterohaemorrhagic E. coli, Yersinia enterocolitica, Shewanella putrefaciens, Listeria monocytogenes and Staphylococcus aureus

Foods ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1786
Author(s):  
György Schneider ◽  
Bettina Schweitzer ◽  
Anita Steinbach ◽  
Botond Zsombor Pertics ◽  
Alysia Cox ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Campylobacter Jejuni ◽  
Food Industry ◽  
Pathogenic Bacteria ◽  
Antibacterial Activities ◽  
Tio2 Nps ◽  
E Coli ◽  
Foodborne Pathogenic Bacteria ◽  
And Staphylococcus Aureus ◽  
Co Doped

Contamination of meats and meat products with foodborne pathogenic bacteria raises serious safety issues in the food industry. The antibacterial activities of phosphorous-fluorine co-doped TiO2 nanoparticles (PF-TiO2) were investigated against seven foodborne pathogenic bacteria: Campylobacter jejuni, Salmonella Typhimurium, Enterohaemorrhagic E. coli, Yersinia enterocolitica, Shewanella putrefaciens, Listeria monocytogenes and Staphylococcus aureus. PF-TiO2 NPs were synthesized hydrothermally at 250 °C for 1, 3, 6 or 12 h, and then tested at three different concentrations (500 μg/mL, 100 μg/mL, 20 μg/mL) for the inactivation of foodborne bacteria under UVA irradiation, daylight exposure or dark conditions. The antibacterial efficacies were compared after 30 min of exposure to light. Distinct differences in the antibacterial activities of the PF-TiO2 NPs, and the susceptibilities of tested foodborne pathogenic bacterium species were found. PF-TiO2/3 h and PF-TiO2/6 h showed the highest antibacterial activity by decreasing the living bacterial cell number from ~106 by ~5 log (L. monocytogenes), ~4 log (EHEC), ~3 log (Y. enterolcolitca, S. putrefaciens) and ~2.5 log (S. aureus), along with complete eradication of C. jejuni and S. Typhimurium. Efficacy of PF-TiO2/1 h and PF-TiO2/12 h NPs was lower, typically causing a ~2–4 log decrease in colony forming units depending on the tested bacterium while the effect of PF-TiO2/0 h was comparable to P25 TiO2, a commercial TiO2 with high photocatalytic activity. Our results show that PF-co-doping of TiO2 NPs enhanced the antibacterial action against foodborne pathogenic bacteria and are potential candidates for use in the food industry as active surface components, potentially contributing to the production of meats that are safe for consumption.

scholarly journals Impacts of climate change on the complex life cycles of fish

2012 ◽  
Vol 22 (2) ◽  
pp. 121-139 ◽  
Author(s):  
Pierre Petitgas ◽  
Adriaan D. Rijnsdorp ◽  
Mark Dickey-Collas ◽  
Georg H. Engelhard ◽  
Myron A. Peck ◽  
...  
Keyword(s):  
Climate Change ◽  
Life Cycles ◽  
Complex Life Cycles ◽  
Impacts Of Climate Change

scholarly journals Transcriptome Analysis of the Cecal Tonsil of Jingxing Yellow Chickens Revealed the Mechanism of Differential Resistance to Salmonella

Genes ◽  
2019 ◽  
Vol 10 (12) ◽  
pp. 979 ◽  
Author(s):  
Fei Wang ◽  
Jin Zhang ◽  
Bo Zhu ◽  
Jie Wang ◽  
Qiao Wang ◽  
...  
Keyword(s):  
Immune Response ◽  
Pathogenic Bacteria ◽  
Molecular Mechanisms ◽  
Differential Resistance ◽  
Receptor Interaction ◽  
Salmonella Infection ◽  
Poultry Products ◽  
Food Borne ◽  
Cecal Tonsil ◽  
Iga Production

Salmonella is one of the most common food-borne pathogens. It can be transmitted between chickens, as well as to people by contaminated poultry products. In our study, we distinguished chickens with different resistances mainly based on bacterial loads. We compared the cecal tonsil transcriptomes between the susceptible and resistant chickens after Salmonella infection, aiming to identify the crucial genes participating in the antibacterial activity in the cecal tonsil. A total of 3214 differentially expressed genes (DEGs), including 2092 upregulated and 1122 downregulated genes, were identified between the two groups (fold change ≥ 2.0, padj < 0.05). Many DEGs were mainly involved in the regulation of two biological processes: crosstalk between the cecal tonsil epithelium and pathogenic bacteria, such as focal adhesion, extracellular-matrix–receptor interaction, and regulation of the actin cytoskeleton and host immune response including the cytokine–receptor interaction. In particular, the challenged resistant birds exhibited strong activation of the intestinal immune network for IgA production, which perhaps contributed to the resistance to Salmonella infection. These findings give insight into the mRNA profile of the cecal tonsil between the two groups after initial Salmonella stimulation, which may extend the known complexity of molecular mechanisms in chicken immune response to Salmonella.

A Report of Four Cases and a Review of the Literature

1974 ◽  
Vol 83 (4) ◽  
pp. 550-554 ◽  
Author(s):  
Gary D. Becker ◽  
Alexander M. Wernicke
Keyword(s):  
World Literature ◽  
Pathogenic Bacteria ◽  
Wide Spectrum ◽  
Carrier State ◽  
Penicillin G ◽  
Physical Finding ◽  
Agar Culture ◽  
Cervical Lymph Nodes ◽  
Procaine Penicillin ◽  
Moderate Elevation

Four cases of gonococcal pharyngotonsillitis have been presented, along with a review of the world literature. This entity is most commonly seen in those individuals practicing fellatio, i.e., females and homosexual males. The infection may be passed to the newborn by the infected genitals of the mother during birth, to the infant from adult molestation, or among sexually promiscuous children. Most gonococcal pharyngeal infections result in a carrier state, and as such, are possible reservoirs of propagated infections. When symptomatic, the most frequent complaint is a sore throat. Physical finding among symptomatic patients reveal a wide spectrum ranging from mild hyperemia of the pharynx or tonsils, to exudative tonsillitis with tender cervical lymph nodes and moderate elevation of temperature. Most authorities agree that the preferred treatment is 4.8 million units of procaine penicillin G I.M., with one gm of probenecid by mouth thirty minutes before the injection. If allergic to penicillin, tetracycline should be given, 1.5 gm by mouth stat, then 0.5 gm four times a day for a total of 9 gm. A routine blood agar culture of the throat will not reveal the presence of the gonococcus. Thayer-Martin (or Transgrow) media must be used. Failure to detect pathogenic bacteria in a routine culture may lead to either no treatment or improper treatment of a gonococcal pharyngotonsillar infection. This may result in a carrier state, or even worse, to a disseminated gonococcal infection.

Complex Life Cycles: Why Refrain from Growth before Reproduction in the Adult Niche?

2013 ◽  
Vol 181 (1) ◽  
pp. 39-51 ◽  
Author(s):  
Daniel P. Benesh ◽  
James C. Chubb ◽  
Geoff A. Parker
Keyword(s):  
Life Cycles ◽  
Complex Life Cycles

Abiotic versus biotic hierarchies in the assembly of parasite populations

Parasitology ◽  
2009 ◽  
Vol 137 (4) ◽  
pp. 743-754 ◽  
Author(s):  
T. K. ANDERSON ◽  
M. V. K. SUKHDEO
Keyword(s):  
Fundulus Heteroclitus ◽  
Classification Tree ◽  
Benthic Invertebrate ◽  
Life Cycles ◽  
Complex Life Cycles ◽  
Parasite Communities ◽  
Parametric Classification ◽  
The Common ◽  
Correct Category ◽  
Parasite Populations

SUMMARYThe presence or absence of parasites within host populations is the result of a complex of factors, both biotic and abiotic. This study uses a non-parametric classification tree approach to evaluate the relative importance of key abiotic and biotic drivers controlling the presence/absence of parasites with complex life cycles in a sentinel, the common killifish Fundulus heteroclitus. Parasite communities were classified from 480 individuals representing 15 fish from 4 distinct marsh sites in each of 4 consecutive seasons between 2006 and 2007. Abiotic parameters were recorded at continuous water monitoring stations located at each of the 4 sites. Classification trees identified the presence of benthic invertebrate species (Gammarus sp. and Littorina sp.) as the most important variables in determining parasite presence: secondary splitters were dominated by abiotic variables including conductance, pH and temperature. Seventy percent of hosts were successfully classified into the correct category (infected/uninfected) based on only these criteria. The presence of competent definitive hosts was not considered to be an important explanatory variable. These data suggest that the most important determinant of the presence of these parasite populations in the common killifish is the availability of diverse communities of benthic invertebrates.

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