Differential transcript expression between the microfilariae of the filarial nematodes, Brugia malayi and B. pahangi

<p>Abstract</p> <p>Background</p> <p><it>Brugia malayi </it>and <it>B. pahangi </it>are two closely related nematodes that cause filariasis in humans and animals. However, <it>B. pahangi </it>microfilariae are able to develop in and be transmitted by the mosquito, <it>Armigeres subalbatus</it>, whereas most <it>B. malayi </it>are rapidly melanized and destroyed within the mosquito hemocoel. A cross-species microarray analysis employing the <it>B. malayi </it>V2 array was carried out to determine the transcriptional differences between <it>B. malayi </it>and <it>B. pahangi </it>microfilariae with similar age distribution.</p> <p>Results</p> <p>Following microarray data analysis, a list of preferentially expressed genes in both microfilariae species was generated with a false discovery rate estimate of 5% and a signal intensity ratio of 2 or higher in either species. A total of 308 probes were preferentially expressed in both species with 149 probes, representing 123 genes, in <it>B. pahangi </it>microfilariae and 159 probes, representing 107 genes, in <it>B. malayi </it>microfilariae. In <it>B. pahangi</it>, there were 76 (62%) up-regulated transcripts that coded for known proteins that mapped into the KEGG pathway compared to 61 (57%) transcripts in <it>B. malayi </it>microfilariae. The remaining 47 (38%) transcripts in <it>B. pahangi </it>and 46 (43%) transcripts in <it>B. malayi </it>microfilariae were comprised almost entirely of hypothetical genes of unknown function. Twenty-seven of the transcripts in <it>B. pahangi </it>microfilariae coded for proteins that associate with the secretory pathway compared to thirty-nine in <it>B. malayi </it>microfilariae. The data obtained from real-time PCR analysis of ten genes selected from the microarray list of preferentially expressed genes showed good concordance with the microarray data, indicating that the microarray data were reproducible.</p> <p>Conclusion</p> <p>In this study, we identified gene transcripts that were preferentially expressed in the microfilariae of <it>B. pahangi </it>and <it>B. malayi</it>, some of which coded for known immunomodulatory proteins. These comparative transcriptome data will be of interest to researchers keen on understanding the inherent differences, at the molecular level, between <it>B. malayi </it>and <it>B. pahangi </it>microfilariae especially because these microfilariae are capable of surviving in the same vertebrate host but elicit different immune response outcomes in the mosquito, <it>Ar. subalbatus</it>.</p

Integrative analysis highlights molecular and immune responses of tick Amblyomma americanum to Escherichia coli challenge

Ticks are ectoparasites that can transmit various pathogens capable of causing life-threatening illnesses in people and animals, making them a severe public health threat. Understanding how ticks respond to bacterial infection is crucial for deciphering their immune defense mechanisms and identifying potential targets for controlling tick-borne diseases. In this study, an in-depth transcriptome analysis was used to investigate the molecular and immune responses of Amblyomma americanum to infection caused by the microinjection of Escherichia coli. With an abundance of differentially expressed genes discovered at different times, the analysis demonstrated significant changes in gene expression profiles in response to E. coli challenge. Notably, we found alterations in crucial immune markers, including the antimicrobial peptides defensin and microplusin, suggesting they may play an essential role in the innate immune response. Furthermore, KEGG analysis showed that following E. coli exposure, a number of key enzymes, including lysosomal alpha-glucosidase, fibroblast growth factor, legumain, apoptotic protease-activating factor, etc., were altered, impacting the activity of the lysosome, mitogen-activated protein kinase, antigen processing and presentation, bacterial invasion, apoptosis, and the Toll and immune deficiency pathways. In addition to the transcriptome analysis, we constructed protein interaction networks to elucidate the molecular interactions underlying the tick’s response to E. coli challenge. Hub genes were identified, and their functional enrichment provided insights into the regulation of cytoskeleton rearrangement, apoptotic processes, and kinase activity that may occur in infected cells. Collectively, the findings shed light on the potential immune responses in A. americanum that control E. coli infection

Transcript and protein expression profile of PF11_0394, a Plasmodium falciparum protein expressed in salivary gland sporozoites

<p>Abstract</p> <p>Background</p> <p><it>Plasmodium falciparum </it>malaria is a significant problem around the world today, thus there is still a need for new control methods to be developed. Because the sporozoite displays dual infectivity for both the mosquito salivary glands and vertebrate host tissue, it is a good target for vaccine development.</p> <p>Methods</p> <p>The <it>P. falciparum </it>gene, <it>PF11_0394</it>, was chosen as a candidate for study due to its potential role in the invasion of host tissues. This gene, which was selected using a data mining approach from PlasmoDB, is expressed both at the transcriptional and protein levels in sporozoites and likely encodes a putative surface protein. Using reverse transcription-polymerase chain reaction (RT-PCR) and green fluorescent protein (GFP)-trafficking studies, a transcript and protein expression profile of PF11_0394 was determined.</p> <p>Results</p> <p>The PF11_0394 protein has orthologs in other <it>Plasmodium </it>species and Apicomplexans, but none outside of the group Apicomplexa. <it>PF11_0394 </it>transcript was found to be present during both the sporozoite and erythrocytic stages of the parasite life cycle, but no transcript was detected during axenic exoerythrocytic stages. Despite the presence of transcript throughout several life cycle stages, the PF11_0394 protein was only detected in salivary gland sporozoites.</p> <p>Conclusions</p> <p>PF11_0394 appears to be a protein uniquely detected in salivary gland sporozoites. Even though a specific function of PF11_0394 has not been determined in <it>P. falciparum </it>biology, it could be another candidate for a new vaccine.</p

Global identification of bursicon-regulated genes in Drosophila melanogaster

Abstract Background Bursicon is a heterodimer neuropeptide responsible for regulating cuticle sclerotization and wing expansion in several insect species. Recent studies indicate that the action of bursicon is mediated by a specific G protein-coupled receptor DLGR2 and the cAMP/PKA signaling pathway. However, little is known regarding the genes that are regulated by bursicon. The identification of bursicon-regulated genes is the focus of this investigation. Results We used DNA microarray analysis to identify bursicon-regulated genes in neck-ligated flies (Drosophila melanogaster) that received recombinant bursicon (r-bursicon). Fifty four genes were found to be regulated by bursicon 1 h post r-bursicon injection, 52 being up-regulated and 2 down-regulated while 33 genes were influenced by r-bursicon 3 h post-injection (24 up-regulated and 9 down-regulated genes). Analysis of these genes by inference from the fly database http://flybase.bio.indiana.edu revealed that these genes encode proteins with diverse functions, including cell signaling, gene transcription, DNA/RNA binding, ion trafficking, proteolysis-peptidolysis, metabolism, cytoskeleton formation, immune response and cell-adhesion. Twenty eight genes randomly selected from the microarray-identified list were verified by real time PCR (qPCR) which supported the microarray data. Temporal response studies of 13 identified and verified genes by qPCR revealed that the temporal expression patterns of these genes are consistent with the microarray data. Conclusion Using r-bursicon, we identified 87 genes that are regulated by bursicon, 30 of which have no previously known function. Most importantly, all genes randomly selected from the microarray-identified list were verified by real time PCR. Temporal analysis of 13 verified genes revealed that the expression of these genes was indeed induced by bursicon and correlated well with the cuticle sclerotization process. The composite data suggest that these genes play important roles in regulating the cuticle sclerotization and wing expansion processes. The data obtained here will form the basis for future studies aimed at elucidating the exact mechanisms upstream from the secretion of bursicon and its binding to target cells

Short-course quinazoline drug treatments are effective in the Litomosoides sigmodontis and Brugia pahangi jird models

The quinazolines CBR417 and CBR490 were previously shown to be potent anti-wolbachials that deplete Wolbachia endosymbionts of filarial nematodes and present promising pre-clinical candidates for human filarial diseases such as onchocerciasis. In the present study we tested both candidates in two models of chronic filarial infection, namely the Litomosoides sigmodontis and Brugia pahangi jird model and assessed their long-term effect on Wolbachia depletion, microfilariae counts and filarial embryogenesis 16-18 weeks after treatment initiation (wpt). Once per day (QD) oral treatment with CBR417 (50 mg/kg) for 4 days or twice per day (BID) with CBR490 (25 mg/kg) for 7 days during patent L. sigmodontis infection reduced the Wolbachia load by >99% and completely cleared peripheral microfilaremia from 10-14 wpt. Similarly, 7 days of QD treatments (40 mg/kg) with CBR417 or CBR490 cleared >99% of Wolbachia from B. pahangi and reduced peritoneal microfilariae counts by 93% in the case of CBR417 treatment. Transmission electron microscopy analysis indicated intensive damage to the B. pahangi ovaries following CBR417 treatment and in accordance filarial embryogenesis was inhibited in both models after CBR417 or CBR490 treatment. Suboptimal treatment regimens of CBR417 or CBR490 did not lead to a maintained reduction of the microfilariae and Wolbachia load. In conclusion, CBR417 or CBR490 are pre-clinical candidates for filarial diseases, which achieve long-term clearance of Wolbachia endosymbionts of filarial nematodes, inhibit filarial embryogenesis and clear microfilaremia with treatments as short as 7 days

How does malaria jump from mosquitoes to humans?

Video of presentation, 72 minutesAssociate Professor in the Department of Veterinary Pathobiology at the University of Missouri-Columbia, Brenda Beerntsen, delivers a lecture on malaria and it's method of transmission from mosquitoes to humans

Genetics of Mosquito Vector Competence

Mosquito-borne diseases are responsible for significant human morbidity and mortality throughout the world. Efforts to control mosquito-borne diseases have been impeded, in part, by the development of drug-resistant parasites, insecticide-resistant mosquitoes, and environmental concerns over the application of insecticides. Therefore, there is a need to develop novel disease control strategies that can complement or replace existing control methods. One such strategy is to generate pathogen-resistant mosquitoes from those that are susceptible. To this end, efforts have focused on isolating and characterizing genes that influence mosquito vector competence. It has been known for over 70 years that there is a genetic basis for the susceptibility of mosquitoes to parasites, but until the advent of powerful molecular biological tools and protocols, it was difficult to assess the interactions of pathogens with their host tissues within the mosquito at a molecular level. Moreover, it has been only recently that the molecular mechanisms responsible for pathogen destruction, such as melanotic encapsulation and immune peptide production, have been investigated. The molecular characterization of genes that influence vector competence is becoming routine, and with the development of the Sindbis virus transducing system, potential antipathogen genes now can be introduced into the mosquito and their effect on parasite development can be assessed in vivo. With the recent successes in the field of mosquito germ line transformation, it seems likely that the generation of a pathogen-resistant mosquito population from a susceptible population soon will become a reality