scholarly journals Response to thermal and infection stresses in an American vector of visceral leishmaniasis

2020 ◽  
Author(s):  
Kelsilandia A. Martins ◽  
Caroline S. Morais ◽  
Susan J. Broughton ◽  
Claudio R. Lazzari ◽  
Paul A. Bates ◽  
...  

AbstractThe phlebotomine sand fly Lutzomyia longipalpis is the primary insect vector of visceral leishmaniasis in the Americas. For ectothermic organisms such as sand flies, the ambient temperature is a critical factor influencing all aspects of their life. However, the impact of temperature has been ignored in previous investigations of stress-induced responses by the vector, such as taking a blood meal or during Leishmania infection. Therefore, this study explored the interaction of Lu. longipalpis with temperature by evaluating sand fly behaviour across a thermal gradient after sugar or blood-feeding, and infection with Leishmania mexicana. Thermographic recordings of sand fly females fed on mice were analysed, and the gene expression of heat shock proteins HSP70 and HSP90(83) was evaluated when insects were exposed to extreme temperatures or infected. The results showed that 72h after blood ingestion females of Lu. longipalpis became less active and preferred relatively low temperatures. However, at later stages of blood digestion females increased their activity and remained at higher temperatures prior to taking a second blood meal; this behaviour seems to be correlated with the evolution of their oocysts and voracity for a second blood meal. No changes in the temperature preferences of female sand flies were recorded in the presence of a gut infection by Le. mexicana, indicating that this parasite has not triggered behavioural immunity in Lu. longipalpis. Real-time imaging showed that the body temperature of female flies feeding on mice increased to the same temperature as the host within a few seconds after landing. The body temperature of females remained around 35 ± 0.5 °C until the end of blood-feeding, revealing a lack of thermoregulatory behaviour. Analysis of expression of heat shock proteins revealed insects increased expression of HSP90(83) when exposed to higher temperatures, such as during blood feeding. Our findings suggest that Lu. longipalpis interacts with the environmental temperature by using its behaviour to avoid temperature-related physiological damage during the gonotrophic cycle. However, the expression of certain heat shock proteins might be triggered to mitigate against thermal stress in situations where a behavioural response is not the best option.

Author(s):  
Claudio R. Lazzari ◽  
Aurélie Fauquet ◽  
Chloé Lahondère ◽  
Ricardo N. Araújo ◽  
Marcos H. Pereira

AbstractFeeding on the blood of warm-blooded vertebrates is associated to thermal stress in haematophagous arthropods. It has been demonstrated that blood-sucking insects protect their physiological integrity either by synthesising heat-shock proteins or by means of thermoregulatory mechanisms. In this work, we describe the first thermoregulatory mechanism in a tick species, Ornithodoros rostratus. By performing real-time infrared thermography during feeding on mice we found that this acarian eliminates big amounts of fluid (urine) through their coxal glands; this fluid quickly spreads over the cuticular surface and its evaporation cools-down the body of the tick. The spread of the fluid is possible thanks to capillary diffusion through the sculptured exoskeleton of Ornithodoros. We discuss our findings in the frame of the adaptive strategies to cope with the thermal stress experienced by blood-sucking arthropods at each feeding event warm-blooded hosts.


2021 ◽  
Vol 11 ◽  
Author(s):  
Abu Saleh Md Moin ◽  
Manjula Nandakumar ◽  
Abdoulaye Diane ◽  
Mohammed Dehbi ◽  
Alexandra E. Butler

Type 1 diabetes (T1D) is a T-cell mediated autoimmune disease characterized by recognition of pancreatic β-cell proteins as self-antigens, called autoantigens (AAgs), followed by loss of pancreatic β-cells. (Pre-)proinsulin ([P]PI), glutamic acid decarboxylase (GAD), tyrosine phosphatase IA-2, and the zinc transporter ZnT8 are key molecules in T1D pathogenesis and are recognized by autoantibodies detected in routine clinical laboratory assays. However, generation of new autoantigens (neoantigens) from β-cells has also been reported, against which the autoreactive T cells show activity. Heat shock proteins (HSPs) were originally described as “cellular stress responders” for their role as chaperones that regulate the conformation and function of a large number of cellular proteins to protect the body from stress. HSPs participate in key cellular functions under both physiological and stressful conditions, including suppression of protein aggregation, assisting folding and stability of nascent and damaged proteins, translocation of proteins into cellular compartments and targeting irreversibly damaged proteins for degradation. Low HSP expression impacts many pathological conditions associated with diabetes and could play a role in diabetic complications. HSPs have beneficial effects in preventing insulin resistance and hyperglycemia in type 2 diabetes (T2D). HSPs are, however, additionally involved in antigen presentation, presenting immunogenic peptides to class I and class II major histocompatibility molecules; thus, an opportunity exists for HSPs to be employed as modulators of immunologic responses in T1D and other autoimmune disorders. In this review, we discuss the multifaceted roles of HSPs in the pathogenesis of T1D and in autoantigen-specific immune protection against T1D development.


Author(s):  
Muhammad Muneeb ◽  
Moazam Ali ◽  
Tahir Sarfaraz ◽  
Wajid Ali ◽  
Zeeshan Ahmad Bhutta

Body of living thing is a complex machine that works on multifunctional processes and needs maintenance. Heat shock protein is a specific type of protein that cares about many normal functions of the body. These proteins have many dynamic occupations to shield the body from various diseases and also a key role in the coiling and uncoiling of proteins, prevent from apoptosis and transportation of proteins. Along with these all properties, the foremost function of these proteins is prevention from cancer and a significant role in cancer diagnosis. Commonly heat shock protein known as chaperones and a wide range of their types have been discovered with their functions as well. Recently many scientists are working on additional investigation of heat shock proteins. This review concludes some basic types of heat shock proteins and their elegant purposes and also providing an open eye for new scientist about a further investigation of heat shock protein.


Author(s):  
N. S. Lutsenko ◽  
T. V. Nedilka

Heat shock proteins (HSP) are important components of the defense mechanism that increases the survival of body cells in adverse conditions due to antiapoptotic and cytoprotective effects. Since their discovery, numerous studies and experimental models have proved the role of HSPs as a key link in the processes of both repair and coagulation of proteins, as well as in the protection of cells from oxidative stress. The potential for pharmacological induction of HSPs in the human body makes them an attractive therapeutic target for many neurodegenerative diseases. This review examines the role of HSPs, especially fraction 70, in the mechanisms of neuroprotection of retinal ganglion cells in primary open-angle glaucoma being one of the common neurodegenerative diseases that can lead to complete loss of visual functions. A number of studies have shown the protective effect of HSP70 on retinal ganglion cells in animals with artificially induced glaucoma. But in the course of experiments on animal models, it was also proved that direct immunization with HSP through intravitreal injections induced pressure-independent degeneration of retinal ganglion cells. This indicates the need for indirect stimulation of HSP70 in order to activate their neuroprotective properties. To date, there are insufficient data on the circulation of HSP70 in the body of a person with glaucoma. These data indicate the prospects for further study of the role of HSP70 in glaucoma degeneration and elucidation of the ways of their mediated induction. Keywords: heat shock protein, HSP70, glaucoma, ganglion cells, retina, neuroprotection.


Author(s):  
Marcos H. Pereira ◽  
Rafaela M. M. Paim ◽  
Chloé Lahondère ◽  
Claudio R. Lazzari

2020 ◽  
pp. 307-325
Author(s):  
Paulo Paes de Andrade ◽  
Cynthia Rayol de Andrade

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Barrack O. Owino ◽  
Jackline Milkah Mwangi ◽  
Steve Kiplagat ◽  
Hannah Njiriku Mwangi ◽  
Johnstone M. Ingonga ◽  
...  

Abstract Background Visceral leishmaniasis (VL) and zoonotic cutaneous leishmaniasis (ZCL) are of public health concern in Merti sub-County, Kenya, but epidemiological data on transmission, vector abundance, distribution, and reservoir hosts remain limited. To better understand the disease and inform control measures to reduce transmission, we investigated the abundance and distribution of sand fly species responsible for Leishmania transmission in the sub-County and their blood-meal hosts. Methods We conducted an entomological survey in five villages with reported cases of VL in Merti sub-County, Kenya, using CDC miniature light traps and castor oil sticky papers. Sand flies were dissected and identified to the species level using standard taxonomic keys and PCR analysis of the cytochrome c oxidase subunit 1 (cox1) gene. Leishmania parasites were detected and identified by PCR and sequencing of internal transcribed spacer 1 (ITS1) genes. Blood-meal sources of engorged females were identified by high-resolution melting analysis of vertebrate cytochrome b (cyt-b) gene PCR products. Results We sampled 526 sand flies consisting of 8 species, Phlebotomus orientalis (1.52%; n = 8), and 7 Sergentomyia spp. Sergentomyia squamipleuris was the most abundant sand fly species (78.71%; n = 414) followed by Sergentomyia clydei (10.46%; n = 55). Leishmania major, Leishmania donovani, and Trypanosoma DNA were detected in S. squamipleuris specimens. Humans were the main sources of sand fly blood meals. However, we also detected mixed blood meals; one S. squamipleuris specimen had fed on both human and mouse (Mus musculus) blood, while two Ph. orientalis specimens fed on human, hyrax (Procavia capensis), and mouse (Mus musculus) blood. Conclusions Our findings implicate the potential involvement of S. squamipleuris in the transmission of Leishmania and question the dogma that human leishmaniases in the Old World are exclusively transmitted by sand flies of the Phlebotomus genus. The presence of Trypanosoma spp. may indicate mechanical transmission, whose efficiency should be investigated. Host preference analysis revealed the possibility of zoonotic transmission of leishmaniasis and other pathogens in the sub-County. Leishmania major and L. donovani are known to cause ZCL and VL, respectively. However, the reservoir status of the parasites is not uniform. Further studies are needed to determine the reservoir hosts of Leishmania spp. in the area.


2021 ◽  
Vol 15 (8) ◽  
pp. e0009682
Author(s):  
Martin J. R. Hall ◽  
Debashis Ghosh ◽  
Daniel Martín-Vega ◽  
Brett Clark ◽  
Innes Clatworthy ◽  
...  

Leishmaniasis is a debilitating disease of the tropics, subtropics and southern Europe caused by Leishmania parasites that are transmitted during blood feeding by phlebotomine sand flies (Diptera: Psychodidae). Using non-invasive micro-computed tomography, we were able to visualize the impact of the laboratory model infection of Lutzomyia longipalpis with Leishmania mexicana and its response to a second blood meal. For the first time we were able to show in 3D the plug of promastigote secretory gel (PSG) and parasites in the distended midgut of whole infected sand flies and measure its volume in relation to that of the midgut. We were also able to measure the degree of opening of the stomodeal valve and demonstrate the extension of the PSG and parasites into the pharynx. Although our pilot study could only examine a few flies, it supports the hypothesis that a second, non-infected, blood meal enhances parasite transmission as we showed that the thoracic PSG-parasite plug in infected flies after a second blood meal was, on average, more than twice the volume of the plug in infected flies that did not have a second blood meal.


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