scholarly journals Yersinia pestis Lipopolysaccharide Remodeling Confers Resistance to a Xenopsylla cheopis Cecropin

Author(s):  
Basil Mathew ◽  
Kari L. Aoyagi ◽  
Mark A. Fisher
2007 ◽  
Vol 44 (4) ◽  
pp. 678-682 ◽  
Author(s):  
Rebecca J. Eisen ◽  
Aryn P. Wilder ◽  
Scott W. Bearden ◽  
John A. Montenieri ◽  
Kenneth L. Gage

2020 ◽  
Vol 57 (6) ◽  
pp. 1997-2001
Author(s):  
Athena Lemon ◽  
Nathan Cherzan ◽  
Viveka Vadyvaloo

Abstract Plague, caused by the flea-transmitted bacterial pathogen Yersinia pestis, is primarily a disease of wild rodents distributed in temperate and tropical zones worldwide. The ability of Y. pestis to develop a biofilm blockage that obstructs the flea foregut proventriculus facilitates its efficient transmission through regurgitation into the host bite site during flea blood sucking. While it is known that temperature influences transmission, it is not well-known if blockage dynamics are similarly in accord with temperature. Here, we determine the influence of the biologically relevant temperatures, 10 and 21°C, on blockage development in flea species, Xenopsylla cheopis (Rothschild) and Oropsylla montana (Baker), respectively, characterized by geographical distribution as cosmopolitan, tropical or endemic, temperate. We find that both species exhibit delayed development of blockage at 10°C. In Y. pestis infected X. cheopis, this is accompanied by significantly lower survival rates and slightly decreased blockage rates, even though these fleas maintain similar rates of persistent infection as at 21°C. Conversely, irrespective of infection status, O. montana withstand 21 and 10°C similarly well and show significant infection rate increases and slightly greater blocking rates at 10 versus 21°C, emphasizing that cooler temperatures are favorable for Y. pestis transmission from this species. These findings assert that temperature is a relevant parameter to consider in assessing flea transmission efficiency in distinct flea species residing in diverse geographical regions that host endemic plague foci. This is important to predict behavioral dynamics of plague regarding epizootic outbreaks and enzootic maintenance and improve timeous implementation of flea control programs.


Author(s):  
Paula Alexandra Oliveira ◽  
Ana Faustino Ana Faustino

ResumoO rato está na base de importantes descobertas na área da medicina. Contudo, nem sempre foi bem visto pela sociedade. No século XIV abateu-se sobre a Europa uma pandemia, a Peste Negra, causada por uma bactéria (Yersinia pestis) transmitida ao Homem por uma pulga (Xenopsylla cheopis), cujo hospedeiro era o rato (Rattus rattus). Esta doença vitimou aproximadamente 150 milhões de pessoas. Estava-se longe de imaginar o contributo que o rato viria a ter na saúde humana.No século XVII o rato proliferou descontroladamente, surgindo uma nova profissão: os caçadores de ratos. Estes indivíduos ganhavam dinheiro com a captura e venda destes animais para alimentação. Nessa época apareceu um desporto novo e as apostas a ele associadas: as lutas de ratos. Como resultado desse desporto, aumentaram os acasalamentos consanguíneos e surgiram variações na pelagem do rato, aparecendo os primeiros ratos albinos. Em 1828 foram utilizados os primeiros ratos albinos num ensaio experimental sobre o estudo do efeito do jejum. Mais tarde, em 1906, no Instituto Wistar, Helen Dean King desenvolveu uma estirpe a partir dos ratos albinos, designada de Wistar, para uso na investigação biomédica.Ainda no século XX o uso do rato de laboratório alargou-se a estudos de aprendizagem em labirinto, nutrição, reprodução, genética e cancro, e consequentemente mais estirpes de animais foram desenvolvidas, passando a existir empresas com o propósito de os vender para investigação. A importância desta espécie pode comprovar-se pela análise do número de artigos publicados anualmente com recurso à sua utilização. Neste trabalho apresenta-se uma revisão histórica do uso do rato na investigação, evidenciando-se as caraterísticas que fizeram deste animal um modelo único na pesquisa biomédica. Palavras-chave: Investigação, Peste Negra, Rattus rattus, Wistar Abstract The rat is the basis of important findings in Medicine. However, it was not always well-seen by the society. In the 14th century, the Europe was affected by a pandemic disease, Black Pestis, caused by a bacterium (Yersinia pestis) transmitted to the Man by a flea (Xenopsylla cheopis), whose host was the rat (Rattus rattus). This disease victimized approximately 150 million people. It was far from imaging the contribution that the rat would have for human health. In the 17th century, the rat proliferated wildly, emerging a new job: the rat hunters. These people earnt money with the capture and selling of these animals for food. At that time appeared a new sport and the bets associated to it: the rat fights. Because of this new hobby, the consanguineous mating increased and appeared variations on rat coat, appearing the first albino rats. In 1828 the albino rats were used by the first time in an experimental assay about the fasting effects. Later, in 1906, in the Wistar Institute, Helen Dean King developed a strain from albino rats, called Wistar, for use in biomedical research. Still in the 20th century, the use of laboratory rats was expanded to studies of learning, nutrition, reproduction, genetics and cancer, and consequently more strains were developed by companies with the purpose to sell them for research. The importance of this specie may be evidenced by the analysis of the number of scientific works published annually using it. In this work, a historical review of the use of the rat in the investigation is provided, evidencing the characteristics that made it a unique model in biomedical research. Keywords: Black Pestis, Investigation, Rattus rattus, Wistar


2020 ◽  
Vol 14 (9) ◽  
pp. e0008688
Author(s):  
David M. Bland ◽  
Craig A. Martens ◽  
Kimmo Virtaneva ◽  
Kishore Kanakabandi ◽  
Dan Long ◽  
...  

2020 ◽  
Vol 14 (5) ◽  
pp. e0008344
Author(s):  
B. Joseph Hinnebusch ◽  
David M. Bland ◽  
Christopher F. Bosio ◽  
Clayton O. Jarrett

2014 ◽  
Vol 8 (9) ◽  
pp. e3196 ◽  
Author(s):  
Christopher F. Bosio ◽  
Austin K. Viall ◽  
Clayton O. Jarrett ◽  
Donald Gardner ◽  
Michael P. Rood ◽  
...  

Microbiology ◽  
2014 ◽  
Vol 160 (11) ◽  
pp. 2517-2525 ◽  
Author(s):  
Tammi L. Johnson ◽  
B. Joseph Hinnebusch ◽  
Karen A. Boegler ◽  
Christine B. Graham ◽  
Katherine MacMillan ◽  
...  

Plague, caused by Yersinia pestis, is characterized by quiescent periods punctuated by rapidly spreading epizootics. The classical ‘blocked flea’ paradigm, by which a blockage forms in the flea’s proventriculus on average 1–2 weeks post-infection (p.i.), forces starving fleas to take multiple blood meals, thus increasing opportunities for transmission. Recently, the importance of early-phase transmission (EPT), which occurs prior to blockage formation, has been emphasized during epizootics. Whilst the physiological and molecular mechanisms of blocked flea transmission are well characterized, the pathogen–vector interactions have not been elucidated for EPT. Within the blocked flea model, Yersinia murine toxin (Ymt) has been shown to be important for facilitating colonization of the midgut within the flea. One proposed mechanism of EPT is the regurgitation of infectious material from the flea midgut during feeding. Such a mechanism would require bacteria to colonize and survive for at least brief periods in the midgut, a process that is mediated by Ymt. Two key bridging vectors of Y. pestis to humans, Oropsylla montana (Siphonaptera: Ceratophyllidae) or Xenopsylla cheopis (Siphonaptera: Pulicidae), were used in our study to test this hypothesis. Fleas were infected with a mutant strain of Y. pestis containing a non-functional ymt that was shown previously to be incapable of colonizing the midgut and were then allowed to feed on SKH-1 mice 3 days p.i. Our results show that Ymt was not required for EPT by either flea species.


Author(s):  
L. P. Bazanova ◽  
E. G. Tokmakova ◽  
G. A. Voronova ◽  
S. V. Balakhonov

Aim. Influence of the plague agent plasmid content on biofilm formation in vivo and death rate of fleas-vectors with different vector activity in experiment were analyzed. Materials and methods. Three Yersinia pestis strains: virulent I-3230 (pYT, pYV, pYP) and I-2638 (pYT, pYV, pYP, pTP 33), and its selected avirulent isogenic clone I-3480 lacking two plasmids (pYV, pYP) were used. Three species of fleas were artificially infected: 477 individuals of Xenopsylla cheopis (a highly active vector), 441 - Citellophilus tesquorum (an active vector), 519 - Frontopsylla lucu-lenta (a low-active vector). The peculiarities of Y. pestis biofilm formation in fleas were estimated by a portion of individuals with bacterial «conglomerates» and «blocks» for a feeding. Death rate of the insects was defined by the percent of the dead fleas at each feeding. Results. All three flea species infected by Y. pestis strains carrying an additional plasmid pTP33 (I-2638 and I-3480) demonstrated the increase of the individual number with various biofilm forms in comparison with the three-plasmid strain I-3230. In X. cheopis it occurred due to the blocked insects, in C. tesquo-rum - mainly due to the fleas containing «conglomerates», in F. luculenta it was completely connected with ectoparasites with «conglomerates». A share of X. cheopis and C. tesquorum died at a feeding was higher in ectoparasites infected with I-3230 strain and F. luculenta - infected by I-2638. Conclusion. Y. pestis strains possessing an additional replicon pTP33 formed a biofilm in the infected insects more often and larger size than a classical three-plasmid variant. Influence of the strain plasmid content on death rate of the infected fleas depended on a vector species.


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