The route of infection determines Wolbachia antibacterial protection in Drosophila.

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Gupta, Vanika; Vasanthakrishnan, Radhakrishnan B; Siva-Jothy, Jonathon; Monteith, Katy M; Brown, Sam P; Vale, Pedro F

2017-06-14

Bacterial symbionts are widespread among metazoans and provide a range of beneficial functions. Wolbachia -mediated protection against viral infection has been extensively demonstrated in Drosophila. In mosquitoes that are artificially transinfected with Drosophila melanogaster Wolbachia (wMel), protection from both viral and bacterial infections has been demonstrated. However, no evidence for Wolbachia -mediated antibacterial protection has been demonstrated in Drosophila to date. Here, we show that the route of infection is key for Wolbachia -mediated antibacterial protection. Drosophila melanogaster carrying Wolbachia showed reduced mortality during enteric-but not systemic-infection with the opportunist pathogen Pseudomonas aeruginosa Wolbachia -mediated protection was more pronounced in male flies and is associated with increased early expression of the antimicrobial peptide Attacin A , and also increased expression of a reactive oxygen species detoxification gene ( Gst D8 ). These results highlight that the route of infection is important for symbiont-mediated protection from infection, that Wolbachia can protect hosts by eliciting a combination of resistance and disease tolerance mechanisms, and that these effects are sexually dimorphic. We discuss the importance of using ecologically relevant routes of infection to gain a better understanding of symbiont-mediated protection. © 2017 The Authors.

Wolbachia enhances West Nile virus (WNV infection in the mosquito Culex tarsalis.

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Brittany L Dodson

2014-07-01

Full Text Available Novel strategies are required to control mosquitoes and the pathogens they transmit. One attractive approach involves maternally inherited endosymbiotic Wolbachia bacteria. After artificial infection with Wolbachia, many mosquitoes become refractory to infection and transmission of diverse pathogens. We evaluated the effects of Wolbachia (wAlbB strain on infection, dissemination and transmission of West Nile virus (WNV in the naturally uninfected mosquito Culex tarsalis, which is an important WNV vector in North America. After inoculation into adult female mosquitoes, Wolbachia reached high titers and disseminated widely to numerous tissues including the head, thoracic flight muscles, fat body and ovarian follicles. Contrary to other systems, Wolbachia did not inhibit WNV in this mosquito. Rather, WNV infection rate was significantly higher in Wolbachia-infected mosquitoes compared to controls. Quantitative PCR of selected innate immune genes indicated that REL1 (the activator of the antiviral Toll immune pathway was down regulated in Wolbachia-infected relative to control mosquitoes. This is the first observation of Wolbachia-induced enhancement of a human pathogen in mosquitoes, suggesting that caution should be applied before releasing Wolbachia-infected insects as part of a vector-borne disease control program.

Wolbachia mediate variation of host immunocompetence.

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Christine Braquart-Varnier

Full Text Available BACKGROUND: After decades during which endosymbionts were considered as silent in their hosts, in particular concerning the immune system, recent studies have revealed the contrary. In the present paper, we addressed the effect of Wolbachia, the most prevalent endosymbiont in arthropods, on host immunocompetence. To this end, we chose the A. vulgare-Wolbachia symbiosis as a model system because it leads to compare consequences of two Wolbachia strains (wVulC and wVulM on hosts from the same population. Moreover, A. vulgare is the only host-species in which Wolbachia have been directly observed within haemocytes which are responsible for both humoral and cellular immune responses. METHODOLOGY/PRINCIPAL FINDINGS: We sampled gravid females from the same population that were either asymbiotic, infected with wVulC, or infected with wVulM. The offspring from these females were tested and it was revealed that individuals harbouring wVulC exhibited: (i lower haemocyte densities, (ii more intense septicaemia in their haemolymph and (iii a reduced lifespan as compared to individuals habouring wVulM or asymbiotic ones. Therefore, individuals in this population of A. vulgare appeared to suffer more from wVulC than from wVulM. Symbiotic titer and location in the haemocytes did not differ for the two Wolbachia strains showing that these two parameters were not responsible for differences observed in their extended phenotypes in A. vulgare. CONCLUSION/SIGNIFICANCE: The two Wolbachia strains infecting A. vulgare in the same population induced variation in immunocompetence and survival of their hosts. Such variation should highly influence the dynamics of this host-symbiont system. We propose in accordance with previous population genetic works, that wVulM is a local strain that has attenuated its virulence through a long term adaptation process towards local A. vulgare genotypes whereas wVulC, which is a widespread and invasive strain, is not locally adapted.

The endosymbiotic bacterium Wolbachia induces resistance to dengue virus in Aedes aegypti.

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Guowu Bian

2010-04-01

Full Text Available Genetic strategies that reduce or block pathogen transmission by mosquitoes have been proposed as a means of augmenting current control measures to reduce the growing burden of vector-borne diseases. The endosymbiotic bacterium Wolbachia has long been promoted as a potential vehicle for introducing disease-resistance genes into mosquitoes, thereby making them refractory to the human pathogens they transmit. Given the large overlap in tissue distribution and intracellular localization between Wolbachia and dengue virus in mosquitoes, we conducted experiments to characterize their interactions. Our results show that Wolbachia inhibits viral replication and dissemination in the main dengue vector, Aedes aegypti. Moreover, the virus transmission potential of Wolbachia-infected Ae. aegypti was significantly diminished when compared to wild-type mosquitoes that did not harbor Wolbachia. At 14 days post-infection, Wolbachia completely blocked dengue transmission in at least 37.5% of Ae. aegypti mosquitoes. We also observed that this Wolbachia-mediated viral interference was associated with an elevated basal immunity and increased longevity in the mosquitoes. These results underscore the potential usefulness of Wolbachia-based control strategies for population replacement.

Wolbachia infection complexity among insects in the tropical rice-field community.

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Kittayapong, P; Jamnongluk, W; Thipaksorn, A; Milne, J R; Sindhusake, C

2003-04-01

Wolbachia are a group of intracellular bacteria that cause reproductive alterations in their arthropod hosts. Widely discordant host and Wolbachia phylogenies indicate that horizontal transmission of these bacteria among species sometimes occurs. A likely means of horizontal transfer is through the feeding relations of organisms within communities. Feeding interactions among insects within the rice-field insect community have been well documented in the past. Here, we present the results of a polymerase chain reaction-based survey and phylogenetic analysis of Wolbachia strains in the rice-field insect community of Thailand. Our field survey indicated that 49 of 209 (23.4%) rice-field insect species were infected with Wolbachia. Of the 49 infected species, 27 were members of two feeding complexes: (i) a group of 13 hoppers preyed on by 2 mirid species and parasitized by a fly species, and (ii) 2 lepidopteran pests parasitized by 9 wasp species. Wolbachia strains found in three hoppers, Recilia dorsalis, Nephotettix malayanus and Nisia nervosa, the two mirid predators, Cyrtorhinus lividipennis and Tytthus chinensis, and the fly parasitoid, Tomosvaryella subvirescens, were all in the same Wolbachia clade. In the second complex, the two lepidopteran pests, Cnaphalocrocis medinalis and Scirpophaga incertulas, were both infected with Wolbachia from the same clade, as was the parasitoid Tropobracon schoenobii. However, none of the other infected parasitoid species in this feeding complex was infected by Wolbachia from this clade. Mean (+/- SD) genetic distance of Wolbachia wsp sequences among interacting species pairs of the hopper feeding complex (0.118 +/- 0.091 nucleotide sequence differences), but not for the other two complexes, was significantly smaller than that between noninteracting species pairs (0.162 +/- 0.079 nucleotide sequence differences). Our results suggest that some feeding complexes, such as the hopper complex described here, could be an important

Genomes of Candidatus Wolbachia bourtzisii wDacA and Candidatus Wolbachia pipientis wDacB from the Cochineal Insect Dactylopius coccus (Hemiptera: Dactylopiidae

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Shamayim T. Ramírez-Puebla

2016-10-01

Full Text Available Dactylopius species, known as cochineal insects, are the source of the carminic acid dye used worldwide. The presence of two Wolbachia strains in Dactylopius coccus from Mexico was revealed by PCR amplification of wsp and sequencing of 16S rRNA genes. A metagenome analysis recovered the genome sequences of Candidatus Wolbachia bourtzisii wDacA (supergroup A and Candidatus Wolbachia pipientis wDacB (supergroup B. Genome read coverage, as well as 16S rRNA clone sequencing, revealed that wDacB was more abundant than wDacA. The strains shared similar predicted metabolic capabilities that are common to Wolbachia, including riboflavin, ubiquinone, and heme biosynthesis, but lacked other vitamin and cofactor biosynthesis as well as glycolysis, the oxidative pentose phosphate pathway, and sugar uptake systems. A complete tricarboxylic acid cycle and gluconeogenesis were predicted as well as limited amino acid biosynthesis. Uptake and catabolism of proline were evidenced in Dactylopius Wolbachia strains. Both strains possessed WO-like phage regions and type I and type IV secretion systems. Several efflux systems found suggested the existence of metal toxicity within their host. Besides already described putative virulence factors like ankyrin domain proteins, VlrC homologs, and patatin-like proteins, putative novel virulence factors related to those found in intracellular pathogens like Legionella and Mycobacterium are highlighted for the first time in Wolbachia. Candidate genes identified in other Wolbachia that are likely involved in cytoplasmic incompatibility were found in wDacB but not in wDacA.

Wolbachia in two populations of Melittobia digitata Dahms (Hymenoptera: Eulophidae)

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Copeland, Claudia S.; Sivinski, John

2008-01-01

We investigated two populations of Melittobia digitata Dahms, a gregarious parasitoid (primarily upon a wide range of solitary bees, wasps, and flies), in search of Wolbachia infection. The first population, from Xalapa, Mexico, was originally collected from and reared on Mexican fruit fly pupae, Anastrepha ludens Loew (Diptera: Tephritidae); the other, from Athens, Georgia, was collected from and reared on prepupae of mud dauber wasps, Trypoxylon politum Say (Hymenoptera: Crabronidae). PCR studies of the ITS2 region corroborated that both parasitoid populations were the same species; this potentially provides a useful molecular taxonomic profile since females of Melittobia species are superficially similar. Amplification of the Wolbachia surface protein gene (wsp) confirmed the presence of this endosymbiont in both populations. Sequencing revealed that the Wolbachia harbored in both populations exhibited a wsp belonging to a unique subgroup (denoted here as Dig) within the B-supergroup of known wsp genes. This new subgroup of wsp may either belong to a different strain of Wolbachia from those previously found to infect Melittobia or may be the result of a recombination event. In either case, known hosts of Wolbachia with a wsp of this subgroup are only distantly related taxonomically. Reasons are advanced as to why Melittobia - an easily reared and managed parasitoid - holds promise as an instructive model organism of Wolbachia infection amenable to the investigation of Wolbachia strains among its diverse hosts. (author)

Heat Sensitivity of wMel Wolbachia during Aedes aegypti Development.

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Jill N Ulrich

2016-07-01

Full Text Available The wMel strain of Wolbachia bacteria is known to prevent dengue and Zika virus transmission in the mosquito vector Aedes aegypti. Accordingly, the release of wMel-infected A. aegypti in endemic regions has been recommended by the World Health Organization as a potential strategy for controlling dengue and Zika outbreaks. However, the utility of this approach could be limited if high temperatures in the aquatic habitats where A. aegypti develop are detrimental to Wolbachia. We exposed wMel-infected A. aegypti eggs and larvae to fluctuating daily temperatures of 30-40°C for three, five, or seven days during their development. We found that Wolbachia levels in females emerging from heat treatments were significantly lower than in the controls that had developed at 20-30°C. Notably, seven days of high temperatures starting at the egg stage reduced Wolbachia levels in emerging females to less than 0.1% of the wMel control levels. However, after adult females returned to 20-30°C for 4-7 days, they experienced differing degrees of Wolbachia recovery. Our findings suggest that the spread of Wolbachia in wild A. aegypti populations and any consequent protection from dengue and Zika viruses might be limited in ecosystems that experience periods of extreme heat, but Wolbachia levels recover partially after temperatures return to normal.

Wolbachia in two populations of Melittobia digitata Dahms (Hymenoptera: Eulophidae)

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Copeland, Claudia S.; Sivinski, John [United States Dept. of Agriculture, Gainesville, FL (United States). Center for Medical, Agriculture and Veterinary Entomology]. E-mails: cclaudia@bioinf.uni-leipzig.de; john.sivinski@ars.usda.gov; Matthews, Robert W. [University of Georgia, Athens, GA (United States). Dept. of Entomology]. E-mail: rmatthew@uga.edu; Gonzalez, Jorge M. [Texas A and M Univ., College Station, TX (United States). Dept. of Entomology]. E-mail: jmgonzalez@neo.tamu.edu; Aluja, Martin [Instituto de Ecologia A.C., Veracruz (Mexico)]. E-mail: martin.aluja@inecol.edu.mx

2008-11-15

We investigated two populations of Melittobia digitata Dahms, a gregarious parasitoid (primarily upon a wide range of solitary bees, wasps, and flies), in search of Wolbachia infection. The first population, from Xalapa, Mexico, was originally collected from and reared on Mexican fruit fly pupae, Anastrepha ludens Loew (Diptera: Tephritidae); the other, from Athens, Georgia, was collected from and reared on prepupae of mud dauber wasps, Trypoxylon politum Say (Hymenoptera: Crabronidae). PCR studies of the ITS2 region corroborated that both parasitoid populations were the same species; this potentially provides a useful molecular taxonomic profile since females of Melittobia species are superficially similar. Amplification of the Wolbachia surface protein gene (wsp) confirmed the presence of this endosymbiont in both populations. Sequencing revealed that the Wolbachia harbored in both populations exhibited a wsp belonging to a unique subgroup (denoted here as Dig) within the B-supergroup of known wsp genes. This new subgroup of wsp may either belong to a different strain of Wolbachia from those previously found to infect Melittobia or may be the result of a recombination event. In either case, known hosts of Wolbachia with a wsp of this subgroup are only distantly related taxonomically. Reasons are advanced as to why Melittobia - an easily reared and managed parasitoid - holds promise as an instructive model organism of Wolbachia infection amenable to the investigation of Wolbachia strains among its diverse hosts. (author)

Cannibalism and predation as paths for horizontal passage of Wolbachia between terrestrial isopods.

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Winka Le Clec'h

Full Text Available The alpha-proteobacteria Wolbachia are the most widespread endosymbionts in arthropods and nematodes. Mainly maternally inherited, these so-called sex parasites have selected several strategies that increase their vertical dispersion in host populations. However, the lack of congruence between the Wolbachia and their host phylogenies suggests frequent horizontal transfers. One way that could be used for horizontal Wolbachia transfers between individuals is predation. The aim of this study was to test whether horizontal passage of Wolbachia is possible when an uninfected terrestrial isopod eats an infected one. After having eaten Armadillidium vulgare harbouring Wolbachia, the predator-recipients (the two woodlice A. vulgare and Porcellio dilatatus dilatatus that were initially Wolbachia-free were tested positive for the presence of Wolbachia both by quantitative PCR and Fluorescence in situ Hybridization (FISH. Even if the titers were low compared to vertically infected individuals, this constitutes the first demonstration of Wolbachia occurrence in various organs of an initially uninfected host after eating an infected one.

A Cell-Based Screen Reveals that the Albendazole Metabolite, Albendazole Sulfone, Targets Wolbachia

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Bray, Walter M.; White, Pamela M.; Ruybal, Jordan; Lokey, R. Scott; Debec, Alain; Sullivan, William

2012-01-01

Wolbachia endosymbionts carried by filarial nematodes give rise to the neglected diseases African river blindness and lymphatic filariasis afflicting millions worldwide. Here we identify new Wolbachia-disrupting compounds by conducting high-throughput cell-based chemical screens using a Wolbachia-infected, fluorescently labeled Drosophila cell line. This screen yielded several Wolbachia-disrupting compounds including three that resembled Albendazole, a widely used anthelmintic drug that targets nematode microtubules. Follow-up studies demonstrate that a common Albendazole metabolite, Albendazole sulfone, reduces intracellular Wolbachia titer both in Drosophila melanogaster and Brugia malayi, the nematode responsible for lymphatic filariasis. Significantly, Albendazole sulfone does not disrupt Drosophila microtubule organization, suggesting that this compound reduces titer through direct targeting of Wolbachia. Accordingly, both DNA staining and FtsZ immunofluorescence demonstrates that Albendazole sulfone treatment induces Wolbachia elongation, a phenotype indicative of binary fission defects. This suggests that the efficacy of Albendazole in treating filarial nematode-based diseases is attributable to dual targeting of nematode microtubules and their Wolbachia endosymbionts. PMID:23028321

Wolbachia infections in native and introduced populations of fire ants (Solenopsis spp.).

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Shoemaker, D D; Ross, K G; Keller, L; Vargo, E L; Werren, J H

2000-12-01

Wolbachia are cytoplasmically inherited bacteria that induce a variety of effects with fitness consequences on host arthropods, including cytoplasmic incompatibility, parthenogenesis, male-killing and feminization. We report here the presence of Wolbachia in native South American populations of the fire ant Solenopsis invicta, but the apparent absence of the bacteria in introduced populations of this pest species in the USA. The Wolbachia strains in native S. invicta are of two divergent types (A and B), and the frequency of infection varies dramatically between geographical regions and social forms of this host. Survey data reveal that Wolbachia also are found in other native fire ant species within the Solenopsis saevissima species complex from South America, including S. richteri. This latter species also has been introduced in the USA, where it lacks Wolbachia. Sequence data reveal complete phylogenetic concordance between mtDNA haplotype in S. invicta and Wolbachia infection type (A or B). In addition, the mtDNA and associated group A Wolbachia strain in S. invicta are more closely related to the mtDNA and Wolbachia strain found in S. richteri than they are to the mtDNA and associated group B Wolbachia in S. invicta. These data are consistent with historical introgression of S. richteri cytoplasmic elements into S. invicta populations, resulting in enhanced infection and mtDNA polymorphisms in S. invicta. Wolbachia may have significant fitness effects on these hosts (either directly or by cytoplasmic incompatibility) and therefore these microbes potentially could be used in biological control programmes to suppress introduced fire ant populations.

Classification of endosymbiont Wolbachia (Rickettsiales: Anaplasmataceae) in opiine wasps (Hymenoptera: Braconidae)

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Mohammed, Muhamad Azmi; Zuki, Ameyra Aman; Yusof, Suhana; Othman, Nurul Wahida; Zain, Badrul Munir Md; Yaakop, Salmah

2018-04-01

Endosymbiont Wolbachia has always been a hot topic of discussion among entomologists and microbiologists as it can manipulate the reproductive system of their arthropod hosts. In this study, a total of 10 sequences which consist of concatenate data from three genetic markers of Wolbachia (groEL, gltA, and wsp) were obtained from opiine wasps from five localities in Peninsular Malaysia. Among the 10 sequences, six were isolated from Fopius arisanus, one from F. vandenboschi, and three from Psyttalia sp. SY2013. Based on Neighbour-Joining (NJ) analysis of the concatenate data and genetic distances, four variants of Wolbachia have been successfully identified. Our data thus provide an insight on Wolbachia infections in oriental insects as Wolbachia research is still considered as in early stage in Malaysia.

Effect of Wolbachia on Dengue infection in Endemic districts of Odisha

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Ipsita Mohanty

2017-10-01

Full Text Available Dengue is the most important arboviral disease posing considerable threat to human and animal health in tropical and subtropical countries. The causative agent for dengue viruses (DENV are primarily the infectious female Aedes aegypti mosquitoes and to a lesser extent its sister taxon infectious female Aedes albopictus mosquitoes. Persistent DENV infections play a role in the cycling pattern of dengue outbreaks. Due to lack of proper treatment, strategies for blocking pathogen transmission by mosquito vectors have been proposed as a means of augmenting current control measures to reduce the growing burden of vector-borne diseases. In this scenario, the use of Wolbachia has been proposed to reduce dengue transmission. Wolbachia, a gram negative endosymbiont bacterium is naturally present in over 20% of all insects including Aedes albopictus mosquito. In our study, polymerase chain reaction (PCR was used to determine the presence of Wolbachia from field collected Ae. albopictus from various parts of the Odisha using wsp primers. Ae. albopictus had Wolbachia infection ranging from 65 to 100%. Field collected Wolbachia infected mosquitoes were challenged with DENV infection. At seven days following infected blood-feeding, an increase in Wolbachia densities was displayed to a greater extent compared to control mosquitoes. Our result indicates that virus-blocking is likely to persist in Wolbachia-infected mosquitoes suggesting that Wolbachia may serve as a successful biocontrol strategy for reducing dengue transmission in the field.

Receptor-mediated uptake of low density lipoprotein stimulates bile acid synthesis by cultured rat hepatocytes

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Junker, L.H.; Davis, R.A.

1989-01-01

The cellular mechanisms responsible for the lipoprotein-mediated stimulation of bile acid synthesis in cultured rat hepatocytes were investigated. Adding 280 micrograms/ml of cholesterol in the form of human or rat low density lipoprotein (LDL) to the culture medium increased bile acid synthesis by 1.8- and 1.6-fold, respectively. As a result of the uptake of LDL, the synthesis of [14C]cholesterol from [2-14C]acetate was decreased and cellular cholesteryl ester mass was increased. Further studies demonstrated that rat apoE-free LDL and apoE-rich high density lipoprotein (HDL) both stimulated bile acid synthesis 1.5-fold, as well as inhibited the formation of [14C]cholesterol from [2-14C]acetate. Reductive methylation of LDL blocked the inhibition of cholesterol synthesis, as well as the stimulation of bile acid synthesis, suggesting that these processes require receptor-mediated uptake. To identify the receptors responsible, competitive binding studies using 125I-labeled apoE-free LDL and 125I-labeled apoE-rich HDL were performed. Both apoE-free LDL and apoE-rich HDL displayed an equal ability to compete for binding of the other, suggesting that a receptor or a group of receptors that recognizes both apolipoproteins is involved. Additional studies show that hepatocytes from cholestyramine-treated rats displayed 2.2- and 3.4-fold increases in the binding of apoE-free LDL and apoE-rich HDL, respectively. These data show for the first time that receptor-mediated uptake of LDL by the liver is intimately linked to processes activating bile acid synthesis

Demographic Variation of Wolbachia Infection in the Endangered Mitchell’s Satyr Butterfly

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Jennifer Fenner

2017-05-01

Full Text Available The Mitchell’s satyr, Neonympha mitchellii, is an endangered species that is limited to highly isolated habitats in the northern and southern United States. Conservation strategies for isolated endangered species often implement captive breeding and translocation programs for repopulation. However, these programs risk increasing the spread of harmful pathogens, such as the bacterial endosymbiont Wolbachia. Wolbachia can manipulate the host’s reproduction leading to incompatibilities between infected and uninfected hosts. This study uses molecular methods to screen for Wolbachia presence across the distribution of the Mitchell’s satyr and its subspecies, St. Francis satyr, which are both federally listed as endangered and are considered two of the rarest butterflies in North America. The screens confirmed the presence of Wolbachia in the northern and newly discovered southern populations of the Mitchell’s satyr, but not in the St. Francis satyr population. These results combined with previous reports of Wolbachia in N. mitchellii, highlight that Wolbachia infection varies both geographically and temporally in satyr populations. The temporal variance shows the importance of continued monitoring of Wolbachia infection during conservation programs. To reduce the risk of reproductive incompatibilities, it is advised that all individuals collected for conservation purposes be screened for Wolbachia and recommended to avoid the use of infected individuals for captive breeding and translocation programs.

Extensive duplication of the Wolbachia DNA in chromosome four of Drosophila ananassae.

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Klasson, Lisa; Kumar, Nikhil; Bromley, Robin; Sieber, Karsten; Flowers, Melissa; Ott, Sandra H; Tallon, Luke J; Andersson, Siv G E; Dunning Hotopp, Julie C

2014-12-12

Lateral gene transfer (LGT) from bacterial Wolbachia endosymbionts has been detected in ~20% of arthropod and nematode genome sequencing projects. Many of these transfers are large and contain a substantial part of the Wolbachia genome. Here, we re-sequenced three D. ananassae genomes from Asia and the Pacific that contain large LGTs from Wolbachia. We find that multiple copies of the Wolbachia genome are transferred to the Drosophila nuclear genome in all three lines. In the D. ananassae line from Indonesia, the copies of Wolbachia DNA in the nuclear genome are nearly identical in size and sequence yielding an even coverage of mapped reads over the Wolbachia genome. In contrast, the D. ananassae lines from Hawaii and India show an uneven coverage of mapped reads over the Wolbachia genome suggesting that different parts of these LGTs are present in different copy numbers. In the Hawaii line, we find that this LGT is underrepresented in third instar larvae indicative of being heterochromatic. Fluorescence in situ hybridization of mitotic chromosomes confirms that the LGT in the Hawaii line is heterochromatic and represents ~20% of the sequence on chromosome 4 (dot chromosome, Muller element F). This collection of related lines contain large lateral gene transfers composed of multiple Wolbachia genomes that constitute >2% of the D. ananassae genome (~5 Mbp) and partially explain the abnormally large size of chromosome 4 in D. ananassae.

A critical re-evaluation of multilocus sequence typing (MLST) efforts in Wolbachia.

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Bleidorn, Christoph; Gerth, Michael

2018-01-01

Wolbachia (Alphaproteobacteria, Rickettsiales) is the most common, and arguably one of the most important inherited symbionts. Molecular differentiation of Wolbachia strains is routinely performed with a set of five multilocus sequence typing (MLST) markers. However, since its inception in 2006, the performance of MLST in Wolbachia strain typing has not been assessed objectively. Here, we evaluate the properties of Wolbachia MLST markers and compare it to 252 other single copy loci present in the genome of most Wolbachia strains. Specifically, we investigated how well MLST performs at strain differentiation, at reflecting genetic diversity of strains, and as phylogenetic marker. We find that MLST loci are outperformed by other loci at all tasks they are currently employed for, and thus that they do not reflect the properties of a Wolbachia strain very well. We argue that whole genome typing approaches should be used for Wolbachia typing in the future. Alternatively, if few loci approaches are necessary, we provide a characterisation of 252 single copy loci for a number a criteria, which may assist in designing specific typing systems or phylogenetic studies. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

The Endosymbiotic Bacterium Wolbachia Selectively Kills Male Hosts by Targeting the Masculinizing Gene.

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Takahiro Fukui

2015-07-01

Full Text Available Pathogens are known to manipulate the reproduction and development of their hosts for their own benefit. Wolbachia is an endosymbiotic bacterium that infects a wide range of insect species. Wolbachia is known as an example of a parasite that manipulates the sex of its host's progeny. Infection of Ostrinia moths by Wolbachia causes the production of all-female progeny, however, the mechanism of how Wolbachia accomplishes this male-specific killing is unknown. Here we show for the first time that Wolbachia targets the host masculinizing gene of Ostrinia to accomplish male-killing. We found that Wolbachia-infected O. furnacalis embryos do not express the male-specific splice variant of doublesex, a gene which acts at the downstream end of the sex differentiation cascade, throughout embryonic development. Transcriptome analysis revealed that Wolbachia infection markedly reduces the mRNA level of Masc, a gene that encodes a protein required for both masculinization and dosage compensation in the silkworm Bombyx mori. Detailed bioinformatic analysis also elucidated that dosage compensation of Z-linked genes fails in Wolbachia-infected O. furnacalis embryos, a phenomenon that is extremely similar to that observed in Masc mRNA-depleted male embryos of B. mori. Finally, injection of in vitro transcribed Masc cRNA into Wolbachia-infected embryos rescued male progeny. Our results show that Wolbachia-induced male-killing is caused by a failure of dosage compensation via repression of the host masculinizing gene. Our study also shows a novel strategy by which a pathogen hijacks the host sex determination cascade.

The Gut Commensal Microbiome of Drosophila melanogaster Is Modified by the Endosymbiont Wolbachia.

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Simhadri, Rama K; Fast, Eva M; Guo, Rong; Schultz, Michaela J; Vaisman, Natalie; Ortiz, Luis; Bybee, Joanna; Slatko, Barton E; Frydman, Horacio M

2017-01-01

Endosymbiotic Wolbachia bacteria and the gut microbiome have independently been shown to affect several aspects of insect biology, including reproduction, development, life span, stem cell activity, and resistance to human pathogens, in insect vectors. This work shows that Wolbachia bacteria, which reside mainly in the fly germline, affect the microbial species present in the fly gut in a lab-reared strain. Drosophila melanogaster hosts two main genera of commensal bacteria- Acetobacter and Lactobacillus . Wolbachia -infected flies have significantly reduced titers of Acetobacter . Sampling of the microbiome of axenic flies fed with equal proportions of both bacteria shows that the presence of Wolbachia bacteria is a significant determinant of the composition of the microbiome throughout fly development. However, this effect is host genotype dependent. To investigate the mechanism of microbiome modulation, the effect of Wolbachia bacteria on Imd and reactive oxygen species pathways, the main regulators of immune response in the fly gut, was measured. The presence of Wolbachia bacteria does not induce significant changes in the expression of the genes for the effector molecules in either pathway. Furthermore, microbiome modulation is not due to direct interaction between Wolbachia bacteria and gut microbes. Confocal analysis shows that Wolbachia bacteria are absent from the gut lumen. These results indicate that the mechanistic basis of the modulation of composition of the microbiome by Wolbachia bacteria is more complex than a direct bacterial interaction or the effect of Wolbachia bacteria on fly immunity. The findings reported here highlight the importance of considering the composition of the gut microbiome and host genetic background during Wolbachia -induced phenotypic studies and when formulating microbe-based disease vector control strategies. IMPORTANCE Wolbachia bacteria are intracellular bacteria present in the microbiome of a large fraction of insects

Broader prevalence of Wolbachia in insects including potential human disease vectors.

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de Oliveira, C D; Gonçalves, D S; Baton, L A; Shimabukuro, P H F; Carvalho, F D; Moreira, L A

2015-06-01

Wolbachia are intracellular, maternally transmitted bacteria considered the most abundant endosymbionts found in arthropods. They reproductively manipulate their host in order to increase their chances of being transmitted to the offspring, and currently are being used as a tool to control vector-borne diseases. Studies on distribution of Wolbachia among its arthropod hosts are important both for better understanding why this bacterium is so common, as well as for its potential use as a biological control agent. Here, we studied the incidence of Wolbachia in a broad range of insect species, collected from different regions of Brazil, using three genetic markers (16S rRNA, wsp and ftsZ), which varied in terms of their sensitivity to detect this bacterium. The overall incidence of Wolbachia among species belonging to 58 families and 14 orders was 61.9%. The most common positive insect orders were Coleoptera, Diptera, Hemiptera and Hymenoptera, with Diptera and Hemiptera having the highest numbers of Wolbachia-positive families. They included potential human disease vectors whose infection status has never been reported before. Our study further shows the importance of using quantitative polymerase chain reaction for high-throughput and sensitive Wolbachia screening.

Influence of Wolbachia on host gene expression in an obligatory symbiosis

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Kremer Natacha

2012-01-01

Full Text Available Abstract Background Wolbachia are intracellular bacteria known to be facultative reproductive parasites of numerous arthropod hosts. Apart from these reproductive manipulations, recent findings indicate that Wolbachia may also modify the host’s physiology, notably its immune function. In the parasitoid wasp, Asobara tabida, Wolbachia is necessary for oogenesis completion, and aposymbiotic females are unable to produce viable offspring. The absence of egg production is also associated with an increase in programmed cell death in the ovaries of aposymbiotic females, suggesting that a mechanism that ensures the maintenance of Wolbachia in the wasp could also be responsible for this dependence. In order to decipher the general mechanisms underlying host-Wolbachia interactions and the origin of the dependence, we developed transcriptomic approaches to compare gene expression in symbiotic and aposymbiotic individuals. Results As no genetic data were available on A. tabida, we constructed several Expressed Sequence Tags (EST libraries, and obtained 12,551 unigenes from this species. Gene expression was compared between symbiotic and aposymbiotic ovaries through in silico analysis and in vitro subtraction (SSH. As pleiotropic functions involved in immunity and development could play a major role in the establishment of dependence, the expression of genes involved in oogenesis, programmed cell death (PCD and immunity (broad sense was analyzed by quantitative RT-PCR. We showed that Wolbachia might interfere with these numerous biological processes, in particular some related to oxidative stress regulation. We also showed that Wolbachia may interact with immune gene expression to ensure its persistence within the host. Conclusions This study allowed us to constitute the first major dataset of the transcriptome of A. tabida, a species that is a model system for both host/Wolbachia and host/parasitoid interactions. More specifically, our results

Wolbachia-associated bacterial protection in the mosquito Aedes aegypti.

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Yixin H Ye

Full Text Available BACKGROUND: Wolbachia infections confer protection for their insect hosts against a range of pathogens including bacteria, viruses, nematodes and the malaria parasite. A single mechanism that might explain this broad-based pathogen protection is immune priming, in which the presence of the symbiont upregulates the basal immune response, preparing the insect to defend against subsequent pathogen infection. A study that compared natural Wolbachia infections in Drosophila melanogaster with the mosquito vector Aedes aegypti artificially transinfected with the same strains has suggested that innate immune priming may only occur in recent host-Wolbachia associations. This same study also revealed that while immune priming may play a role in viral protection it cannot explain the entirety of the effect. METHODOLOGY/FINDINGS: Here we assess whether the level of innate immune priming induced by different Wolbachia strains in A. aegypti is correlated with the degree of protection conferred against bacterial pathogens. We show that Wolbachia strains wMel and wMelPop, currently being tested for field release for dengue biocontrol, differ in their protective abilities. The wMelPop strain provides stronger, more broad-based protection than wMel, and this is likely explained by both the higher induction of immune gene expression and the strain-specific activation of particular genes. We also show that Wolbachia densities themselves decline during pathogen infection, likely as a result of the immune induction. CONCLUSIONS/SIGNIFICANCE: This work shows a correlation between innate immune priming and bacterial protection phenotypes. The ability of the Toll pathway, melanisation and antimicrobial peptides to enhance viral protection or to provide the basis of malaria protection should be further explored in the context of this two-strain comparison. This work raises the questions of whether Wolbachia may improve the ability of wild mosquitoes to survive pathogen

Wolbachia influences the maternal transmission of the gypsy endogenous retrovirus in Drosophila melanogaster.

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Touret, Franck; Guiguen, François; Terzian, Christophe

2014-09-02

The endosymbiotic bacteria of the genus Wolbachia are present in most insects and are maternally transmitted through the germline. Moreover, these intracellular bacteria exert antiviral activity against insect RNA viruses, as in Drosophila melanogaster, which could explain the prevalence of Wolbachia bacteria in natural populations. Wolbachia is maternally transmitted in D. melanogaster through a mechanism that involves distribution at the posterior pole of mature oocytes and then incorporation into the pole cells of the embryos. In parallel, maternal transmission of several endogenous retroviruses is well documented in D. melanogaster. Notably, gypsy retrovirus is expressed in permissive follicle cells and transferred to the oocyte and then to the offspring by integrating into their genomes. Here, we show that the presence of Wolbachia wMel reduces the rate of gypsy insertion into the ovo gene. However, the presence of Wolbachia does not modify the expression levels of gypsy RNA and envelope glycoprotein from either permissive or restrictive ovaries. Moreover, Wolbachia affects the pattern of distribution of the retroviral particles and the gypsy envelope protein in permissive follicle cells. Altogether, our results enlarge the knowledge of the antiviral activity of Wolbachia to include reducing the maternal transmission of endogenous retroviruses in D. melanogaster. Animals have established complex relationships with bacteria and viruses that spread horizontally among individuals or are vertically transmitted, i.e., from parents to offspring. It is well established that members of the genus Wolbachia, maternally inherited symbiotic bacteria present mainly in arthropods, reduce the replication of several RNA viruses transmitted horizontally. Here, we demonstrate for the first time that Wolbachia diminishes the maternal transmission of gypsy, an endogenous retrovirus in Drosophila melanogaster. We hypothesize that gypsy cannot efficiently integrate into the germ

Wolbachia utilizes host microtubules and Dynein for anterior localization in the Drosophila oocyte.

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Patrick M Ferree

2005-10-01

Full Text Available To investigate the role of the host cytoskeleton in the maternal transmission of the endoparasitic bacteria Wolbachia, we have characterized their distribution in the female germ line of Drosophila melanogaster. In the germarium, Wolbachia are distributed to all germ cells of the cyst, establishing an early infection in the cell destined to become the oocyte. During mid-oogenesis, Wolbachia exhibit a distinct concentration between the anterior cortex and the nucleus in the oocyte, where many bacteria appear to contact the nuclear envelope. Following programmed rearrangement of the microtubule network, Wolbachia dissociate from this anterior position and become dispersed throughout the oocyte. This localization pattern is distinct from mitochondria and all known axis determinants. Manipulation of microtubules and cytoplasmic Dynein and Dynactin, but not Kinesin-1, disrupts anterior bacterial localization in the oocyte. In live egg chambers, Wolbachia exhibit movement in nurse cells but not in the oocyte, suggesting that the bacteria are anchored by host factors. In addition, we identify mid-oogenesis as a period in the life cycle of Wolbachia in which bacterial replication occurs. Total bacterial counts show that Wolbachia increase at a significantly higher rate in the oocyte than in the average nurse cell, and that normal Wolbachia levels in the oocyte depend on microtubules. These findings demonstrate that Wolbachia utilize the host microtubule network and associated proteins for their subcellular localization in the Drosophila oocyte. These interactions may also play a role in bacterial motility and replication, ultimately leading to the bacteria's efficient maternal transmission.

Perturbed cholesterol and vesicular trafficking associated with dengue blocking in Wolbachia-infected Aedes aegypti cells.

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Geoghegan, Vincent; Stainton, Kirsty; Rainey, Stephanie M; Ant, Thomas H; Dowle, Adam A; Larson, Tony; Hester, Svenja; Charles, Philip D; Thomas, Benjamin; Sinkins, Steven P

2017-09-13

Wolbachia are intracellular maternally inherited bacteria that can spread through insect populations and block virus transmission by mosquitoes, providing an important approach to dengue control. To better understand the mechanisms of virus inhibition, we here perform proteomic quantification of the effects of Wolbachia in Aedes aegypti mosquito cells and midgut. Perturbations are observed in vesicular trafficking, lipid metabolism and in the endoplasmic reticulum that could impact viral entry and replication. Wolbachia-infected cells display a differential cholesterol profile, including elevated levels of esterified cholesterol, that is consistent with perturbed intracellular cholesterol trafficking. Cyclodextrins have been shown to reverse lipid accumulation defects in cells with disrupted cholesterol homeostasis. Treatment of Wolbachia-infected Ae. aegypti cells with 2-hydroxypropyl-β-cyclodextrin restores dengue replication in Wolbachia-carrying cells, suggesting dengue is inhibited in Wolbachia-infected cells by localised cholesterol accumulation. These results demonstrate parallels between the cellular Wolbachia viral inhibition phenotype and lipid storage genetic disorders. Wolbachia infection of mosquitoes can block dengue virus infection and is tested in field trials, but the mechanism of action is unclear. Using proteomics, Geoghegan et al. here identify effects of Wolbachia on cholesterol homeostasis and dengue virus replication in Aedes aegypti.

Wolbachia-induced aae-miR-12 miRNA negatively regulates the expression of MCT1 and MCM6 genes in Wolbachia-infected mosquito cell line.

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Solomon Osei-Amo

Full Text Available BACKGROUND: Best recognized for its role in manipulating host reproduction, the parasitic gram-negative Wolbachia pipientis is known to colonize a wide range of invertebrates. The endosymbiotic bacterium has recently been shown to cause a life-shortening effect as well as inhibiting replication of arboviruses in Aedes aegypti; although the molecular mechanisms behind these effects are largely unknown. MicroRNAs (miRNAs have been determined to have a wide range of roles in regulating gene expression in eukaryotes. A recent study showed that several A. aegypti mosquito miRNAs are differentially expressed when infected with Wolbachia. METHODOLOGY/PRINCIPAL FINDINGS: Based on the prior knowledge that one of these miRNAs, aae-miR-12, is differentially expressed in mosquitoes infected with Wolbachia, we aimed to determine any significance of this mediation. We also set out to characterize the target genes of this miRNA in the A. aegpyti genome. Bioinformatic approaches predicted a list of potential target genes and subsequent functional analyses confirmed that two of these, DNA replication licensing (MCM6 and monocarboxylate transporter (MCT1, are under the regulative control of aae-miR-12. We also demonstrated that aae-miR-12 is critical in the persistence of Wolbachia in the host cell. CONCLUSIONS/SIGNIFICANCE: Our study has identified two target genes of aae-miR-12, a differentially expressed mosquito miRNA in Wolbachia-infected cells, and determined that the miRNA affects Wolbachia density in the host cells.

Cytonuclear Epistasis Controls the Density of Symbiont Wolbachia pipientis in Nongonadal Tissues of Mosquito Culex quinquefasciatus.

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Emerson, Kevin J; Glaser, Robert L

2017-08-07

Wolbachia pipientis , a bacterial symbiont infecting arthropods and nematodes, is vertically transmitted through the female germline and manipulates its host's reproduction to favor infected females. Wolbachia also infects somatic tissues where it can cause nonreproductive phenotypes in its host, including resistance to viral pathogens. Wolbachia -mediated phenotypes are strongly associated with the density of Wolbachia in host tissues. Little is known, however, about how Wolbachia density is regulated in native or heterologous hosts. Here, we measure the broad-sense heritability of Wolbachia density among families in field populations of the mosquito Culex pipiens , and show that densities in ovary and nongonadal tissues of females in the same family are not correlated, suggesting that Wolbachia density is determined by distinct mechanisms in the two tissues. Using introgression analysis between two different strains of the closely related species C. quinquefasciatus , we show that Wolbachia densities in ovary tissues are determined primarily by cytoplasmic genotype, while densities in nongonadal tissues are determined by both cytoplasmic and nuclear genotypes and their epistatic interactions. Quantitative-trait-locus mapping identified two major-effect quantitative-trait loci in the C. quinquefasciatus genome explaining a combined 23% of variance in Wolbachia density, specifically in nongonadal tissues. A better understanding of how Wolbachia density is regulated will provide insights into how Wolbachia density can vary spatiotemporally in insect populations, leading to changes in Wolbachia -mediated phenotypes such as viral pathogen resistance. Copyright © 2017 Emerson, Glaser.

Detection of Wolbachia endobacteria in Culex quinquefasciatus by Gimenez staining and confirmation by PCR.

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Muniaraj, M; Paramasivan, R; Sunish, I P; Arunachalam, N; Mariappan, T; Jerald Leo, S Victor; Dhananjeyan, K J

2012-12-01

Wolbachia are common intracellular bacteria that are found in arthropods and nematodes. These endosymbionts are transmitted vertically through host eggs and alter host biology in diverse ways, including the induction of reproductive manipulations, such as feminization, parthenogenesis, male killing and sperm-egg incompatibility. Since they can also move horizontally across species boundaries, Wolbachia is gaining importance in recent days as it could be used as a biological control agent to control vector mosquitoes or for paratransgenic approaches. However, the study of Wolbachia requires sophisticated techniques such as PCR and cell culture facilities which cannot be affordable for many laboratories where the diseases transmitted by arthropod vectors are common. Hence, it would be beneficial to develop a simple method to detect the presence of Wolbachia in arthropods. In this study, we described a method of staining Wolbachia endobacteria, present in the reproductive tissues of mosquitoes. The reliability of this method was compared with Gram staining and PCR based detection. The microscopic observation of the Gimenez stained smear prepared from the teased ovary of wild caught and Wolbachia (+) Cx. quinquefasciatus revealed the presence of pink coloured pleomorphic cells of Wolbachia ranging from cocci, comma shaped cells to bacillus and chain forms. The ovaries of Wolbachia (-) cured mosquito did not show any cell. Although Gram's staining is a reliable differential staining for the other bacteria, the bacterial cells in the smears from the ovaries of wild caught mosquitoes did not take the stain properly and the cells were not clearly visible. The PCR amplified product from the pooled remains of wild caught and Wolbachia (+) Cx. quinquefasciatus showed clear banding, whereas, no banding was observed for the negative control (distilled water) and Wolbachia (-) Cx. quinquefasciatus. The Gimenez staining technique applied, could be used to detect the members of

Survey on the Ability of Wolbachia to Control Human Viral, Protozoan, and Filarial Disease Pathogens

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Garedaghi Yagoob

2014-04-01

Full Text Available Objective: Most human filarial nematode parasites and arthropods are hosts for a bacterial endosymbiont, Wolbachia. In filariasis, Wolbachia are required for normal development, fertility, and survival. However, in arthropods, Wolbachia are largely parasitic and can influence development and reproduction, but are generally not required for host survival. Materials and Methods: Due to their obligate nature in filarial parasites, Wolbachia have been a target for drug discovery initiatives using several approaches including diversity and focused library screening and genomic sequence analysis. Results: In vitro and in vivo anti-Wolbachia antibiotic treatments have been shown to have adulticidal activity, a long sought goal of filarial parasite drug discovery. In mosquitoes, it has been shown that the presence of Wolbachia can inhibit the transmission of certain viruses, such as dengue, chikungunya, yellow fever, West Nile, as well as the infectivity of the malaria-causing protozoan, Plasmodium and filarial nematodes. Conclusion: Wolbachia can cause a form of conditional sterility that can be used to suppress populations of mosquitoes and additional medically important insects. Thus, Wolbachia, a pandemic endosymbiont, offers great potential for elimination of a wide-variety of devastating human diseases.

Genome-wide analysis of the interaction between the endosymbiotic bacterium Wolbachia and its Drosophila host

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Xi, Zhiyong; Gavotte, Laurent; Xie, Yan; Dobson, Stephen L

2008-01-01

Background Intracellular Wolbachia bacteria are obligate, maternally-inherited, endosymbionts found frequently in insects and other invertebrates. The success of Wolbachia can be attributed in part to an ability to alter host reproduction via mechanisms including cytoplasmic incompatibility (CI), parthenogenesis, feminization and male killing. Despite substantial scientific effort, the molecular mechanisms underlying the Wolbachia/host interaction are unknown. Results Here, an in vitro Wolbachia infection was generated in the Drosophila S2 cell line, and transcription profiles of infected and uninfected cells were compared by microarray. Differentially-expressed patterns related to reproduction, immune response and heat stress response are observed, including multiple genes that have been previously reported to be involved in the Wolbachia/host interaction. Subsequent in vivo characterization of differentially-expressed products in gonads demonstrates that Angiotensin Converting Enzyme (Ance) varies between Wolbachia infected and uninfected flies and that the variation occurs in a sex-specific manner. Consistent with expectations for the conserved CI mechanism, the observed Ance expression pattern is repeatable in different Drosophila species and with different Wolbachia types. To examine Ance involvement in the CI phenotype, compatible and incompatible crosses of Ance mutant flies were conducted. Significant differences are observed in the egg hatch rate resulting from incompatible crosses, providing support for additional experiments examining for an interaction of Ance with the CI mechanism. Conclusion Wolbachia infection is shown to affect the expression of multiple host genes, including Ance. Evidence for potential Ance involvement in the CI mechanism is described, including the prior report of Ance in spermatid differentiation, Wolbachia-induced sex-specific effects on Ance expression and an Ance mutation effect on CI levels. The results support the use of

Genome-wide analysis of the interaction between the endosymbiotic bacterium Wolbachia and its Drosophila host.

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Xi, Zhiyong; Gavotte, Laurent; Xie, Yan; Dobson, Stephen L

2008-01-02

Intracellular Wolbachia bacteria are obligate, maternally-inherited, endosymbionts found frequently in insects and other invertebrates. The success of Wolbachia can be attributed in part to an ability to alter host reproduction via mechanisms including cytoplasmic incompatibility (CI), parthenogenesis, feminization and male killing. Despite substantial scientific effort, the molecular mechanisms underlying the Wolbachia/host interaction are unknown. Here, an in vitro Wolbachia infection was generated in the Drosophila S2 cell line, and transcription profiles of infected and uninfected cells were compared by microarray. Differentially-expressed patterns related to reproduction, immune response and heat stress response are observed, including multiple genes that have been previously reported to be involved in the Wolbachia/host interaction. Subsequent in vivo characterization of differentially-expressed products in gonads demonstrates that Angiotensin Converting Enzyme (Ance) varies between Wolbachia infected and uninfected flies and that the variation occurs in a sex-specific manner. Consistent with expectations for the conserved CI mechanism, the observed Ance expression pattern is repeatable in different Drosophila species and with different Wolbachia types. To examine Ance involvement in the CI phenotype, compatible and incompatible crosses of Ance mutant flies were conducted. Significant differences are observed in the egg hatch rate resulting from incompatible crosses, providing support for additional experiments examining for an interaction of Ance with the CI mechanism. Wolbachia infection is shown to affect the expression of multiple host genes, including Ance. Evidence for potential Ance involvement in the CI mechanism is described, including the prior report of Ance in spermatid differentiation, Wolbachia-induced sex-specific effects on Ance expression and an Ance mutation effect on CI levels. The results support the use of Wolbachia infected cell cultures

Wolbachia strain wPip yields a pattern of cytoplasmic incompatibility enhancing a Wolbachia-based suppression strategy against the disease vector Aedes albopictus

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Calvitti Maurizio

2012-11-01

Full Text Available Abstract Background Cytoplasmic incompatibility (CI is induced in nature by Wolbachia bacteria, resulting in conditional male sterility. Previous research demonstrated that the two Wolbachia strains (wAlbA and wAlbB that naturally co-infect the disease vector mosquito Aedes albopictus (Asian tiger mosquito can be replaced with the wPip Wolbachia strain from Culex pipiens. Since Wolbachia-based vector control strategies depend upon the strength and consistency of CI, a greater understanding is needed on the CI relationships between wPip, wAlbA and wAlbB Wolbachia in Ae. albopictus. Methods This work consisted of a collaborative series of crosses carried out in Italy and in US to study the CI relationships between the “wPip” infected Ae. albopictus strain (ARwP and the superinfected SR strain. The Ae. albopictus strains used in Italian tests are the wPip infected ARwP strain (ARwPIT, the superinfected SR strain and the aposymbiotic AR strain. To understand the observed pattern of CI, crossing experiments carried out in USA focused on the study of the CI relationships between ARwP (ARwPUS and artificially-generated single infected lines, in specific HTA and HTB, harbouring only wAlbA and wAlbB Wolbachia respectively. Results The paper reports an unusual pattern of CI observed in crossing experiments between ARwP and SR lines. Specifically, ARwP males are able to induce full sterility in wild type females throughout most of their lifetime, while crosses between SR males and ARwP females become partially fertile with male aging. We demonstrated that the observed decrease in CI penetrance with SR male age, is related to the previously described decrease in Wolbachia density, in particular of the wAlbA strain, occurring in aged superinfected males. Conclusions The results here reported support the use of the ARwP Ae. albopictus line as source of “ready-made sterile males”, as an alternative to gamma radiation sterilized males, for autocidal

Wolbachia infection reduces blood-feeding success in the dengue fever mosquito, Aedes aegypti.

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Turley, Andrew P; Moreira, Luciano A; O'Neill, Scott L; McGraw, Elizabeth A

2009-09-15

The mosquito Aedes aegypti was recently transinfected with a life-shortening strain of the endosymbiont Wolbachia pipientis (wMelPop) as the first step in developing a biocontrol strategy for dengue virus transmission. In addition to life-shortening, the wMelPop-infected mosquitoes also exhibit increased daytime activity and metabolic rates. Here we sought to quantify the blood-feeding behaviour of Wolbachia-infected females as an indicator of any virulence or energetic drain associated with Wolbachia infection. In a series of blood-feeding trials in response to humans, we have shown that Wolbachia-infected mosquitoes do not differ in their response time to humans, but that as they age they obtain fewer and smaller blood meals than Wolbachia-uninfected controls. Lastly, we observed a behavioural characteristic in the Wolbachia infected mosquitoes best described as a "bendy" proboscis that may explain the decreased biting success. Taken together the evidence suggests that wMelPop infection may be causing tissue damage in a manner that intensifies with mosquito age and that leads to reduced blood-feeding success. These behavioural changes require further investigation with respect to a possible physiological mechanism and their role in vectorial capacity of the insect. The selective decrease of feeding success in older mosquitoes may act synergistically with other Wolbachia-associated traits including life-shortening and viral protection in biocontrol strategies.

Comprehensive proteome profiling in Aedes albopictus to decipher Wolbachia-arbovirus interference phenomenon.

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Saucereau, Yoann; Valiente Moro, Claire; Dieryckx, Cindy; Dupuy, Jean-William; Tran, Florence-Hélène; Girard, Vincent; Potier, Patrick; Mavingui, Patrick

2017-08-18

Aedes albopictus is a vector of arboviruses that cause severe diseases in humans such as Chikungunya, Dengue and Zika fevers. The vector competence of Ae. albopictus varies depending on the mosquito population involved and the virus transmitted. Wolbachia infection status in believed to be among key elements that determine viral transmission efficiency. Little is known about the cellular functions mobilized in Ae. albopictus during co-infection by Wolbachia and a given arbovirus. To decipher this tripartite interaction at the molecular level, we performed a proteome analysis in Ae. albopictus C6/36 cells mono-infected by Wolbachia wAlbB strain or Chikungunya virus (CHIKV), and bi-infected. We first confirmed significant inhibition of CHIKV by Wolbachia. Using two-dimensional gel electrophoresis followed by nano liquid chromatography coupled with tandem mass spectrometry, we identified 600 unique differentially expressed proteins mostly related to glycolysis, translation and protein metabolism. Wolbachia infection had greater impact on cellular functions than CHIKV infection, inducing either up or down-regulation of proteins associated with metabolic processes such as glycolysis and ATP metabolism, or structural glycoproteins and capsid proteins in the case of bi-infection with CHIKV. CHIKV infection inhibited expression of proteins linked with the processes of transcription, translation, lipid storage and miRNA pathways. The results of our proteome profiling have provided new insights into the molecular pathways involved in tripartite Ae. albopictus-Wolbachia-CHIKV interaction and may help defining targets for the better implementation of Wolbachia-based strategies for disease transmission control.

Dietary saccharides and sweet tastants have differential effects on colonization of Drosophila oocytes by Wolbachia endosymbionts

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Moises Camacho

2017-07-01

Full Text Available Wolbachia bacteria are widespread, maternally transmitted endosymbionts of insects. Maintenance of sufficient Wolbachia titer in maternal germline cells is required for transmission efficacy. The mechanisms that regulate Wolbachia titer are not well understood; however, dietary sucrose was reported to elevate oocyte Wolbachia titer in Drosophila melanogaster whereas dietary yeast decreased oocyte titer. To further investigate how oocyte Wolbachia titer is controlled, this study analyzed the response of wMel Wolbachia to diets enriched in an array of natural sugars and other sweet tastants. Confocal imaging of D. melanogaster oocytes showed that food enriched in dietary galactose, lactose, maltose and trehalose elevated Wolbachia titer. However, oocyte Wolbachia titers were unaffected by exposure to the sweet tastants lactulose, erythritol, xylitol, aspartame and saccharin as compared to the control. Oocyte size was generally non-responsive to the nutrient-altered diets. Ovary size, however, was consistently smaller in response to all sugar- and sweetener-enriched diets. Furthermore, most dietary sugars administered in tandem with dietary yeast conferred complete rescue of oocyte titer suppression by yeast. All diets dually enriched in yeast and sugar also rescued yeast-associated ovary volume changes. This indicates oocyte colonization by Wolbachia to be a nutritionally sensitive process regulated by multiple mechanistic inputs.

Influence of oxidative homeostasis on bacterial density and cost of infection in Drosophila-Wolbachia symbioses.

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Monnin, D; Kremer, N; Berny, C; Henri, H; Dumet, A; Voituron, Y; Desouhant, E; Vavre, F

2016-06-01

The evolution of symbioses along the continuum between parasitism and mutualism can be influenced by the oxidative homeostasis, that is the balance between reactive oxygen species (ROS) and antioxidant molecules. Indeed, ROS can contribute to the host immune defence to regulate symbiont populations, but are also toxic. This interplay between ROS and symbiosis is notably exemplified by recent results in arthropod-Wolbachia interactions. Wolbachia are symbiotic bacteria involved in a wide range of interactions with their arthropods hosts, from facultative, parasitic associations to obligatory, mutualistic ones. In this study, we used Drosophila-Wolbachia associations to determine whether the oxidative homeostasis plays a role in explaining the differences between phenotypically distinct arthropod-Wolbachia symbioses. We used Drosophila lines with different Wolbachia infections and measured the effects of pro-oxidant (paraquat) and antioxidant (glutathione) treatments on the Wolbachia density and the host survival. We show that experimental manipulations of the oxidative homeostasis can reduce the cost of the infection through its effect on Wolbachia density. We discuss the implication of this result from an evolutionary perspective and argue that the oxidative homeostasis could underlie the evolution of tolerance and dependence on Wolbachia. © 2016 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2016 European Society For Evolutionary Biology.

A cascade of destabilizations: Combining Wolbachia and Allee effects to eradicate insect pests.

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Blackwood, Julie C; Vargas, Roger; Fauvergue, Xavier

2018-01-01

The management of insect pests has long been dominated by the use of chemical insecticides, with the aim of instantaneously killing enough individuals to limit their damage. To minimize unwanted consequences, environmentally friendly approaches have been proposed that utilize biological control and take advantage of intrinsic demographic processes to reduce pest populations. We address the feasibility of a novel pest management strategy based on the release of insects infected with Wolbachia, which causes cytoplasmic incompatibilities in its host population, into a population with a pre-existing Allee effect. We hypothesize that the transient decline in population size caused by a successful invasion of Wolbachia can bring the population below its Allee threshold and, consequently, trigger extinction. We develop a stochastic population model that accounts for Wolbachia-induced cytoplasmic incompatibilities in addition to an Allee effect arising from mating failures at low population densities. Using our model, we identify conditions under which cytoplasmic incompatibilities and Allee effects successfully interact to drive insect pest populations towards extinction. Based on our results, we delineate control strategies based on introductions of Wolbachia-infected insects. We extend this analysis to evaluate control strategies that implement successive introductions of two incompatible Wolbachia strains. Additionally, we consider methods that combine Wolbachia invasion with mating disruption tactics to enhance the pre-existing Allee effect. We demonstrate that Wolbachia-induced cytoplasmic incompatibility and the Allee effect act independently from one another: the Allee effect does not modify the Wolbachia invasion threshold, and cytoplasmic incompatibilities only have a marginal effect on the Allee threshold. However, the interaction of these two processes can drive even large populations to extinction. The success of this method can be amplified by the

Life and death of an influential passenger: Wolbachia and the evolution of CI-modifiers by their hosts.

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Arnulf Koehncke

Full Text Available Wolbachia are intracellular bacteria widely distributed among arthropods and nematodes. In many insect species these bacteria induce a cytoplasmic incompatibility (CI between sperm of infected males and eggs of uninfected females. From an evolutionary point of view, CI is puzzling: In order to induce this modification-rescue system, Wolbachia affect sperm of infected males even though Wolbachia are only transmitted maternally. Phylogenetic studies of Wolbachia and hosts show that the bacteria rarely cospeciate with their hosts, indicating that infections are lost in host species. However, the mechanisms leading to Wolbachia loss are not well understood.Using a population genetic model, we investigate the spread of host mutants that enhance or repress Wolbachia action by affecting either bacterial transmission or the level of CI. We show that host mutants that decrease CI-levels in males (e.g. by reducing Wolbachia-density during spermatogenesis spread, even at cost to mutant males. Increase of these mutants can lead to loss of Wolbachia infections, either as a direct consequence of their increase or in a step-wise manner, and we derive analytically a threshold penetrance above which a mutation's spread leads to extinction of Wolbachia. Selection on host modifiers is sexually antagonistic in that, conversely, host mutants that enhance Wolbachia in females are favoured whereas suppressors are not.Our results indicate that Wolbachia is likely to be lost from host populations on long evolutionary time scales due to reduction of CI levels in males. This can occur either by evolution of single host modifiers with large effects or through accumulation of several modifier alleles with small effects on Wolbachia action, even at cost to mutant males and even if infected hosts do not incur fecundity costs. This possibility is consistent with recent findings and may help to explain the apparent short evolutionary persistence times of Wolbachia in many host

AmiD Is a Novel Peptidoglycan Amidase in Wolbachia Endosymbionts of Drosophila melanogaster

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Miriam Wilmes

2017-08-01

Full Text Available Wolbachia endobacteria are obligate intracellular bacteria with a highly reduced genome infecting many arthropod and filarial species, in which they manipulate arthropod reproduction to increase their transmission and are essential for nematode development and survival. The Wolbachia genome encodes all enzymes required for the synthesis of the cell wall building block lipid II, although a peptidoglycan-like structure has not been detected. Despite the ability to synthesize lipid II, Wolbachia from arthropods and nematodes have only a subset of genes encoding enzymes involved in the periplasmic processing of lipid II and peptidoglycan recycling, with arthropods having two more than nematodes. We functionally analyzed the activity of the putative cell wall hydrolase AmiD from the Wolbachia endosymbiont of Drosophila melanogaster, an enzyme not encoded by the nematode endobacteria. Wolbachia AmiD has Zn2+-dependent amidase activity and cleaves intact peptidoglycan, monomeric lipid II and anhydromuropeptides, substrates that are generated during bacterial growth. AmiD may have been maintained in arthropod Wolbachia to avoid host immune recognition by degrading cell wall fragments in the periplasm. This is the first description of a wolbachial lipid II processing enzyme putatively expressed in the periplasm.

Impacts of temperature and crowding on sex ratio, fecundity and Wolbachia infection intensity in the copepod, Mesocyclops thermocyclopoides.

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Wiwatanaratanabutr, Itsanun; Grandjean, Frederic

2016-11-01

Wolbachia are a group of intracellular bacteria that cause reproductive alterations in arthropods. Here, we describe the effects of two environmental factors (crowding and temperature) on phenotypic expression of feminization, the host's fecundity and Wolbachia infection intensity among life cycle stages in the naturally Wolbachia-infected copepod, Mesocyclops thermocyclopoides. The copepod was first found to be co-infected with Wolbachia A- and B-supergroups Wolbachia strains based on wsp primers. The relative Wolbachia infection intensity within individuals was determined using quantitative real-time PCR and was significantly higher in the B-supergroup than in the A-supergroup. Experimental results of temperature effect on bacterial density in each developmental stage revealed a significant decrease in Wolbachia infection intensity following exposure to high temperature (37°C) in both sexes and implied that Wolbachia might survive in room temperature (25°C) better than in high temperature. Experimental results of crowding effects on Wolbachia infection intensity suggested a negative correlation between copepod nauplii and Wolbachia infection intensity. No effect of rearing temperature on the sex ratio was reported although the fecundity was significantly decreased by high temperature. The results showed that Wolbachia infection intensity to be correlated with crowding conditions and was decreased following exposure of elevated temperature. Copyright © 2016 Elsevier Inc. All rights reserved.

Wolbachia-induced paternal defect in Drosophila is likely by interaction with the juvenile hormone pathway.

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Liu, Chen; Wang, Jia-Lin; Zheng, Ya; Xiong, En-Juan; Li, Jing-Jing; Yuan, Lin-Ling; Yu, Xiao-Qiang; Wang, Yu-Feng

2014-06-01

Wolbachia are endosymbionts that infect many insect species. They can manipulate the host's reproduction to increase their own maternal transmission. Cytoplasmic incompatibility (CI) is one such manipulation, which is expressed as embryonic lethality when Wolbachia-infected males mate with uninfected females. However, matings between males and females carrying the same Wolbachia strain result in viable progeny. The molecular mechanisms of CI are currently not clear. We have previously reported that the gene Juvenile hormone-inducible protein 26 (JhI-26) exhibited the highest upregulation in the 3rd instar larval testes of Drosophila melanogaster when infected by Wolbachia. This is reminiscent of an interaction between Wolbachia and juvenile hormone (JH) pathway in flies. Considering that Jhamt gene encodes JH acid methyltransferase, a key regulatory enzyme of JH biosynthesis, and that methoprene-tolerant (Met) has been regarded as the best JH receptor candidate, we first compared the expression of Jhamt and Met between Wolbachia-infected and uninfected fly testes to investigate whether Wolbachia infection influence the JH signaling pathway. We found that the expressions of Jhamt and Met were significantly increased in the presence of Wolbachia, suggesting an interaction of Wolbachia with the JH signaling pathway. Then, we found that overexpression of JhI-26 in Wolbachia-free transgenic male flies caused paternal-effect lethality that mimics the defects associated with CI. JhI-26 overexpressing males resulted in significantly decrease in hatch rate. Surprisingly, Wolbachia-infected females could rescue the egg hatch. In addition, we showed that overexpression of JhI-26 caused upregulation of the male accessory gland protein (Acp) gene CG10433, but not vice versa. This result suggests that JhI-26 may function at the upstream of CG10433. Likewise, overexpression of CG10433 also resulted in paternal-effect lethality. Both JhI-26 and CG10433 overexpressing males

Frequency of infection with A and B supergroup Wolbachia in ...

Indian Academy of Sciences (India)

Previous surveys indicated that it is commonly seen in 16–76% of arthropods. In this paper, using polymerase chain reaction assay based on specific amplification of the ftsZ-A and -B supergroup Wolbachia gene fragments, we found that 30% of insects and pests screened were positive for Wolbachia. Among them 66.7% ...

Wolbachia infection reduces blood-feeding success in the dengue fever mosquito, Aedes aegypti.

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Andrew P Turley

Full Text Available BACKGROUND: The mosquito Aedes aegypti was recently transinfected with a life-shortening strain of the endosymbiont Wolbachia pipientis (wMelPop as the first step in developing a biocontrol strategy for dengue virus transmission. In addition to life-shortening, the wMelPop-infected mosquitoes also exhibit increased daytime activity and metabolic rates. Here we sought to quantify the blood-feeding behaviour of Wolbachia-infected females as an indicator of any virulence or energetic drain associated with Wolbachia infection. METHODOLOGY/PRINCIPAL FINDINGS: In a series of blood-feeding trials in response to humans, we have shown that Wolbachia-infected mosquitoes do not differ in their response time to humans, but that as they age they obtain fewer and smaller blood meals than Wolbachia-uninfected controls. Lastly, we observed a behavioural characteristic in the Wolbachia infected mosquitoes best described as a "bendy" proboscis that may explain the decreased biting success. CONCLUSIONS/SIGNIFICANCE: Taken together the evidence suggests that wMelPop infection may be causing tissue damage in a manner that intensifies with mosquito age and that leads to reduced blood-feeding success. These behavioural changes require further investigation with respect to a possible physiological mechanism and their role in vectorial capacity of the insect. The selective decrease of feeding success in older mosquitoes may act synergistically with other Wolbachia-associated traits including life-shortening and viral protection in biocontrol strategies.

Draft Genome Assembly of a Wolbachia Endosymbiont of Plutella australiana.

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Ward, Christopher M; Baxter, Simon W

2017-10-26

Wolbachia spp. are endosymbiotic bacteria that infect around 50% of arthropods and cause a broad range of effects, including manipulating host reproduction. Here, we present the annotated draft genome assembly of Wolbachia strain wAus, which infects Plutella australiana , a cryptic ally of the major Brassica pest Plutella xylostella (diamondback moth). Copyright © 2017 Ward and Baxter.

Wolbachia Influences the Maternal Transmission of the gypsy Endogenous Retrovirus in Drosophila melanogaster

OpenAIRE

Touret, Franck; Guiguen, Francois; Terzian, Christophe

2014-01-01

The endosymbiotic bacteria of the genus Wolbachia are present in most insects and are maternally transmitted through the germline. Moreover, these intracellular bacteria exert antiviral activity against insect RNA viruses, as in Drosophila melanogaster, which could explain the prevalence of Wolbachia bacteria in natural populations. Wolbachia is maternally transmitted in D. melanogaster through a mechanism that involves distribution at the posterior pole of mature oocytes and then incorporati...

Wolbachia-induced cytoplasmic incompatibility is associated with decreased Hira expression in male Drosophila.

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Ya Zheng

Full Text Available BACKGROUND: Wolbachia are obligate endosymbiotic bacteria that infect numerous species of arthropods and nematodes. Wolbachia can induce several reproductive phenotypes in their insect hosts including feminization, male-killing, parthenogenesis and cytoplasmic incompatibility (CI. CI is the most common phenotype and occurs when Wolbachia-infected males mate with uninfected females resulting in no or very low numbers of viable offspring. However, matings between males and females infected with the same strain of Wolbachia result in viable progeny. Despite substantial scientific effort, the molecular mechanisms underlying CI are currently unknown. METHODOLOGY/PRINCIPAL FINDINGS: Gene expression studies were undertaken in Drosophila melanogaster and D. simulans which display differential levels of CI using quantitative RT-PCR. We show that Hira expression is correlated with the induction of CI and occurs in a sex-specific manner. Hira expression is significantly lower in males which induce strong CI when compared to males inducing no CI or Wolbachia-uninfected males. A reduction in Hira expression is also observed in 1-day-old males that induce stronger CI compared to 5-day-old males that induce weak or no CI. In addition, Hira mutated D. melanogaster males mated to uninfected females result in significantly decreased hatch rates comparing with uninfected crosses. Interestingly, wMel-infected females may rescue the hatch rates. An obvious CI phenotype with chromatin bridges are observed in the early embryo resulting from Hira mutant fertilization, which strongly mimics the defects associated with CI. CONCLUSIONS/SIGNIFICANCE: Our results suggest Wolbachia-induced CI in Drosophila occurs due to a reduction in Hira expression in Wolbachia-infected males leading to detrimental effects on sperm fertility resulting in embryo lethality. These results may help determine the underlying mechanism of CI and provide further insight in to the important role

Determination of Wolbachia Diversity in Butterflies from Western Ghats, India, by a Multigene Approach

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Salunke, Bipinchandra K.; Salunkhe, Rahul C.; Dhotre, Dhiraj P.; Walujkar, Sandeep A.; Khandagale, Avinash B.; Chaudhari, Rahul; Chandode, Rakesh K.; Ghate, Hemant V.; Patole, Milind S.; Werren, John H.

2012-01-01

Members of the genus Wolbachia are intracellular bacteria that are widespread in arthropods and establish diverse symbiotic associations with their hosts, ranging from mutualism to parasitism. Here we present the first detailed analyses of Wolbachia in butterflies from India with screening of 56 species. Twenty-nine species (52%) representing five families were positive for Wolbachia. This is the first report of Wolbachia infection in 27 of the 29 species; the other two were reported previously. This study also provides the first evidence of infection in the family Papilionidae. A striking diversity was observed among Wolbachia strains in butterfly hosts based on five multilocus sequence typing (MLST) genes, with 15 different sequence types (STs). Thirteen STs are new to the MLST database, whereas ST41 and ST125 were reported earlier. Some of the same host species from this study carried distinctly different Wolbachia strains, whereas the same or different butterfly hosts also harbored closely related Wolbachia strains. Butterfly-associated STs in the Indian sample originated by recombination and point mutation, further supporting the role of both processes in generating Wolbachia diversity. Recombination was detected only among the STs in this study and not in those from the MLST database. Most of the strains were remarkably similar in their wsp genotype, despite divergence in MLST. Only two wsp alleles were found among 25 individuals with complete hypervariable region (HVR) peptide profiles. Although both wsp and MLST show variability, MLST gives better separation between the strains. Completely different STs were characterized for the individuals sharing the same wsp alleles. PMID:22504801

Loss of Wolbachia infection during colonisation in the invasive Argentine ant Linepithema humile

DEFF Research Database (Denmark)

Reuter, M.; Pedersen, Jes Søe; Keller, L.

2005-01-01

Wolbachia are maternally inherited bacteria, which are very common in arthropods and nematodes. Wolbachia infection may affect host reproduction through feminisation, parthenogenesis, male-killing, cytoplasmic incompatibility and increased fecundity. Previous studies showing discrepancies between...... of Wolbachia were studied in three native and eight introduced populations of the Argentine ant Linepithema humile. The screening shows that the symbiont is common in the three native L. humile populations analysed. In contrast, Wolbachia was detected in only one of the introduced populations. The loss...... transmission of the symbiont may be important in ants as suggested by the sequence similarity of strains in the three genera Linepithema, Acromyrmex, and Solenopsis native from South and Central America....

Loss of Wolbachia infection during colonisation in the invasive Argentine ant Linepithema humile.

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Reuter, M; Pedersen, J S; Keller, L

2005-03-01

WOLBACHIA are maternally inherited bacteria, which are very common in arthropods and nematodes. Wolbachia infection may affect host reproduction through feminisation, parthenogenesis, male-killing, cytoplasmic incompatibility and increased fecundity. Previous studies showing discrepancies between the phylogenies of Wolbachia and its arthropod hosts indicate that infection is frequently lost, but the causes of symbiont extinction have so far remained elusive. Here, we report data showing that colonisation of new habitats is a possible mechanism leading to the loss of infection. The presence and prevalence of Wolbachia were studied in three native and eight introduced populations of the Argentine ant Linepithema humile. The screening shows that the symbiont is common in the three native L. humile populations analysed. In contrast, Wolbachia was detected in only one of the introduced populations. The loss of infection associated with colonisation of new habitats may result from drift (founder effect) or altered selection pressures in the new habitat. Furthermore, a molecular phylogeny based on sequences of the Wolbachia wsp gene indicates that L. humile has been infected by a single strain. Horizontal transmission of the symbiont may be important in ants as suggested by the sequence similarity of strains in the three genera Linepithema, Acromyrmex, and Solenopsis native from South and Central America.

Comparative Analysis of Wolbachia Genomes Reveals Streamlining and Divergence of Minimalist Two-Component Systems

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Christensen, Steen; Serbus, Laura Renee

2015-01-01

Two-component regulatory systems are commonly used by bacteria to coordinate intracellular responses with environmental cues. These systems are composed of functional protein pairs consisting of a sensor histidine kinase and cognate response regulator. In contrast to the well-studied Caulobacter crescentus system, which carries dozens of these pairs, the streamlined bacterial endosymbiont Wolbachia pipientis encodes only two pairs: CckA/CtrA and PleC/PleD. Here, we used bioinformatic tools to compare characterized two-component system relays from C. crescentus, the related Anaplasmataceae species Anaplasma phagocytophilum and Ehrlichia chaffeensis, and 12 sequenced Wolbachia strains. We found the core protein pairs and a subset of interacting partners to be highly conserved within Wolbachia and these other Anaplasmataceae. Genes involved in two-component signaling were positioned differently within the various Wolbachia genomes, whereas the local context of each gene was conserved. Unlike Anaplasma and Ehrlichia, Wolbachia two-component genes were more consistently found clustered with metabolic genes. The domain architecture and key functional residues standard for two-component system proteins were well-conserved in Wolbachia, although residues that specify cognate pairing diverged substantially from other Anaplasmataceae. These findings indicate that Wolbachia two-component signaling pairs share considerable functional overlap with other α-proteobacterial systems, whereas their divergence suggests the potential for regulatory differences and cross-talk. PMID:25809075

The effect of virus-blocking Wolbachia on male competitiveness of the dengue vector mosquito, Aedes aegypti.

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Segoli, Michal; Hoffmann, Ary A; Lloyd, Jane; Omodei, Gavin J; Ritchie, Scott A

2014-12-01

The bacterial endosymbiont Wolbachia blocks the transmission of dengue virus by its vector mosquito Aedes aegypti, and is currently being evaluated for control of dengue outbreaks. Wolbachia induces cytoplasmic incompatibility (CI) that results in the developmental failure of offspring in the cross between Wolbachia-infected males and uninfected females. This increases the relative success of infected females in the population, thereby enhancing the spread of the beneficial bacterium. However, Wolbachia spread via CI will only be feasible if infected males are sufficiently competitive in obtaining a mate under field conditions. We tested the effect of Wolbachia on the competitiveness of A. aegypti males under semi-field conditions. In a series of experiments we exposed uninfected females to Wolbachia-infected and uninfected males simultaneously. We scored the competitiveness of infected males according to the proportion of females producing non-viable eggs due to incompatibility. We found that infected males were equally successful to uninfected males in securing a mate within experimental tents and semi-field cages. This was true for males infected by the benign wMel Wolbachia strain, but also for males infected by the virulent wMelPop (popcorn) strain. By manipulating male size we found that larger males had a higher success than smaller underfed males in the semi-field cages, regardless of their infection status. The results indicate that Wolbachia infection does not reduce the competitiveness of A. aegypti males. Moreover, the body size effect suggests a potential advantage for lab-reared Wolbachia-males during a field release episode, due to their better nutrition and larger size. This may promote Wolbachia spread via CI in wild mosquito populations and underscores its potential use for disease control.

Comparative genomics of Wolbachia and the bacterial species concept.

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Kirsten Maren Ellegaard

2013-04-01

Full Text Available The importance of host-specialization to speciation processes in obligate host-associated bacteria is well known, as is also the ability of recombination to generate cohesion in bacterial populations. However, whether divergent strains of highly recombining intracellular bacteria, such as Wolbachia, can maintain their genetic distinctness when infecting the same host is not known. We first developed a protocol for the genome sequencing of uncultivable endosymbionts. Using this method, we have sequenced the complete genomes of the Wolbachia strains wHa and wNo, which occur as natural double infections in Drosophila simulans populations on the Seychelles and in New Caledonia. Taxonomically, wHa belong to supergroup A and wNo to supergroup B. A comparative genomics study including additional strains supported the supergroup classification scheme and revealed 24 and 33 group-specific genes, putatively involved in host-adaptation processes. Recombination frequencies were high for strains of the same supergroup despite different host-preference patterns, leading to genomic cohesion. The inferred recombination fragments for strains of different supergroups were of short sizes, and the genomes of the co-infecting Wolbachia strains wHa and wNo were not more similar to each other and did not share more genes than other A- and B-group strains that infect different hosts. We conclude that Wolbachia strains of supergroup A and B represent genetically distinct clades, and that strains of different supergroups can co-exist in the same arthropod host without converging into the same species. This suggests that the supergroups are irreversibly separated and that barriers other than host-specialization are able to maintain distinct clades in recombining endosymbiont populations. Acquiring a good knowledge of the barriers to genetic exchange in Wolbachia will advance our understanding of how endosymbiont communities are constructed from vertically and horizontally

Sex ratio and Wolbachia infection in the ant Formica exsecta.

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Keller, L; Liautard, C; Reuter, M; Brown, W D; Sundström, L; Chapuisat, M

2001-08-01

Sex allocation data in social Hymenoptera provide some of the best tests of kin selection, parent-offspring conflict and sex ratio theories. However, these studies critically depend on controlling for confounding ecological factors and on identifying all parties that potentially manipulate colony sex ratio. It has been suggested that maternally inherited parasites may influence sex allocation in social Hymenoptera. If the parasites can influence sex allocation, infected colonies are predicted to invest more resources in females than non-infected colonies, because the parasites are transmitted through females but not males. Prime candidates for such sex ratio manipulation are Wolbachia, because these cytoplasmically transmitted bacteria have been shown to affect the sex ratio of host arthropods by cytoplasmic incompatibility, parthenogenesis, male-killing and feminization. In this study, we tested whether Wolbachia infection is associated with colony sex ratio in two populations of the ant Formica exsecta that have been the subject of extensive sex ratio studies. In these populations colonies specialize in the production of one sex or the other. We found that almost all F. exsecta colonies in both populations are infected with Wolbachia. However, in neither population did we find a significant association in the predicted direction between the prevalence of Wolbachia and colony sex ratio. In particular, colonies with a higher proportion of infected workers did not produce more females. Hence, we conclude that Wolbachia does not seem to alter the sex ratio of its hosts as a means to increase transmission rate in these two populations of ants.

Wolbachia Blocks Currently Circulating Zika Virus Isolates in Brazilian Aedes aegypti Mosquitoes.

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Dutra, Heverton Leandro Carneiro; Rocha, Marcele Neves; Dias, Fernando Braga Stehling; Mansur, Simone Brutman; Caragata, Eric Pearce; Moreira, Luciano Andrade

2016-06-08

The recent association of Zika virus with cases of microcephaly has sparked a global health crisis and highlighted the need for mechanisms to combat the Zika vector, Aedes aegypti mosquitoes. Wolbachia pipientis, a bacterial endosymbiont of insect, has recently garnered attention as a mechanism for arbovirus control. Here we report that Aedes aegypti harboring Wolbachia are highly resistant to infection with two currently circulating Zika virus isolates from the recent Brazilian epidemic. Wolbachia-harboring mosquitoes displayed lower viral prevalence and intensity and decreased disseminated infection and, critically, did not carry infectious virus in the saliva, suggesting that viral transmission was blocked. Our data indicate that the use of Wolbachia-harboring mosquitoes could represent an effective mechanism to reduce Zika virus transmission and should be included as part of Zika control strategies. Copyright © 2016 The Author(s). Published by Elsevier Inc. All rights reserved.

Detection of Spiroplasma and Wolbachia in the bacterial gonad community of Chorthippus parallelus.

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Martínez-Rodríguez, P; Hernández-Pérez, M; Bella, J L

2013-07-01

We have recently detected the endosymbiont Wolbachia in multiple individuals and populations of the grasshopper Chorthippus parallelus (Orthoptera: acrididae). This bacterium induces reproductive anomalies, including cytoplasmic incompatibility. Such incompatibilities may help explain the maintenance of two distinct subspecies of this grasshopper, C. parallelus parallelus and C. parallelus erythropus, which are involved in a Pyrenean hybrid zone that has been extensively studied for the past 20 years, becoming a model system for the study of genetic divergence and speciation. To evaluate whether Wolbachia is the sole bacterial infection that might induce reproductive anomalies, the gonadal bacterial community of individuals from 13 distinct populations of C. parallelus was determined by denaturing gradient gel electrophoresis analysis of bacterial 16S rRNA gene fragments and sequencing. The study revealed low bacterial diversity in the gonads: a persistent bacterial trio consistent with Spiroplasma sp. and the two previously described supergroups of Wolbachia (B and F) dominated the gonad microbiota. A further evaluation of the composition of the gonad bacterial communities was carried out by whole cell hybridization. Our results confirm previous studies of the cytological distribution of Wolbachia in C. parallelus gonads and show a homogeneous infection by Spiroplasma. Spiroplasma and Wolbachia cooccurred in some individuals, but there was no significant association of Spiroplasma with a grasshopper's sex or with Wolbachia infection, although subtle trends might be detected with a larger sample size. This information, together with previous experimental crosses of this grasshopper, suggests that Spiroplasma is unlikely to contribute to sex-specific reproductive anomalies; instead, they implicate Wolbachia as the agent of the observed anomalies in C. parallelus.

The AWED trial (Applying Wolbachia to Eliminate Dengue) to assess the efficacy of Wolbachia-infected mosquito deployments to reduce dengue incidence in Yogyakarta, Indonesia: study protocol for a cluster randomised controlled trial.

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Anders, Katherine L; Indriani, Citra; Ahmad, Riris Andono; Tantowijoyo, Warsito; Arguni, Eggi; Andari, Bekti; Jewell, Nicholas P; Rances, Edwige; O'Neill, Scott L; Simmons, Cameron P; Utarini, Adi

2018-05-31

Dengue and other arboviruses transmitted by Aedes aegypti mosquitoes, including Zika and chikungunya, present an increasing public health challenge in tropical regions. Current vector control strategies have failed to curb disease transmission, but continue to be employed despite the absence of robust evidence for their effectiveness or optimal implementation. The World Mosquito Program has developed a novel approach to arbovirus control using Ae. aegypti stably transfected with Wolbachia bacterium, with a significantly reduced ability to transmit dengue, Zika and chikungunya in laboratory experiments. Modelling predicts this will translate to local elimination of dengue in most epidemiological settings. This study protocol describes the first trial to measure the efficacy of Wolbachia in reducing dengue virus transmission in the field. The study is a parallel, two-arm, non-blinded cluster randomised controlled trial conducted in a single site in Yogyakarta, Indonesia. The aim is to determine whether large-scale deployment of Wolbachia-infected Ae. aegypti mosquitoes leads to a measurable reduction in dengue incidence in treated versus untreated areas. The primary endpoint is symptomatic, virologically confirmed dengue virus infection of any severity. The 26 km 2 study area was subdivided into 24 contiguous clusters, allocated randomly 1:1 to receive Wolbachia deployments or no intervention. We use a novel epidemiological study design, the cluster-randomised test-negative design trial, in which dengue cases and arbovirus-negative controls are sampled concurrently from among febrile patients presenting to a network of primary care clinics, with case or control status classified retrospectively based on the results of laboratory diagnostic testing. Efficacy is estimated from the odds ratio of Wolbachia exposure distribution (probability of living in a Wolbachia-treated area) among virologically confirmed dengue cases compared to test-negative controls. A secondary

Wolbachia symbiont infections induce strong cytoplasmic incompatibility in the tsetse fly Glossina morsitans.

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Uzma Alam

2011-12-01

Full Text Available Tsetse flies are vectors of the protozoan parasite African trypanosomes, which cause sleeping sickness disease in humans and nagana in livestock. Although there are no effective vaccines and efficacious drugs against this parasite, vector reduction methods have been successful in curbing the disease, especially for nagana. Potential vector control methods that do not involve use of chemicals is a genetic modification approach where flies engineered to be parasite resistant are allowed to replace their susceptible natural counterparts, and Sterile Insect technique (SIT where males sterilized by chemical means are released to suppress female fecundity. The success of genetic modification approaches requires identification of strong drive systems to spread the desirable traits and the efficacy of SIT can be enhanced by identification of natural mating incompatibility. One such drive mechanism results from the cytoplasmic incompatibility (CI phenomenon induced by the symbiont Wolbachia. CI can also be used to induce natural mating incompatibility between release males and natural populations. Although Wolbachia infections have been reported in tsetse, it has been a challenge to understand their functional biology as attempts to cure tsetse of Wolbachia infections by antibiotic treatment damages the obligate mutualistic symbiont (Wigglesworthia, without which the flies are sterile. Here, we developed aposymbiotic (symbiont-free and fertile tsetse lines by dietary provisioning of tetracycline supplemented blood meals with yeast extract, which rescues Wigglesworthia-induced sterility. Our results reveal that Wolbachia infections confer strong CI during embryogenesis in Wolbachia-free (Gmm(Apo females when mated with Wolbachia-infected (Gmm(Wt males. These results are the first demonstration of the biological significance of Wolbachia infections in tsetse. Furthermore, when incorporated into a mathematical model, our results confirm that Wolbachia can

Defining Brugia malayi and Wolbachia symbiosis by stage-specific dual RNA-seq.

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Alexandra Grote

2017-03-01

Full Text Available Filarial nematodes currently infect up to 54 million people worldwide, with millions more at risk for infection, representing the leading cause of disability in the developing world. Brugia malayi is one of the causative agents of lymphatic filariasis and remains the only human filarial parasite that can be maintained in small laboratory animals. Many filarial nematode species, including B. malayi, carry an obligate endosymbiont, the alpha-proteobacteria Wolbachia, which can be eliminated through antibiotic treatment. Elimination of the endosymbiont interferes with development, reproduction, and survival of the worms within the mamalian host, a clear indicator that the Wolbachia are crucial for survival of the parasite. Little is understood about the mechanism underlying this symbiosis.To better understand the molecular interplay between these two organisms we profiled the transcriptomes of B. malayi and Wolbachia by dual RNA-seq across the life cycle of the parasite. This helped identify functional pathways involved in this essential symbiotic relationship provided by the co-expression of nematode and bacterial genes. We have identified significant stage-specific and gender-specific differential expression in Wolbachia during the nematode's development. For example, during female worm development we find that Wolbachia upregulate genes involved in ATP production and purine biosynthesis, as well as genes involved in the oxidative stress response.This global transcriptional analysis has highlighted specific pathways to which both Wolbachia and B. malayi contribute concurrently over the life cycle of the parasite, paving the way for the development of novel intervention strategies.

The wMel strain of Wolbachia Reduces Transmission of Zika virus by Aedes aegypti.

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Aliota, Matthew T; Peinado, Stephen A; Velez, Ivan Dario; Osorio, Jorge E

2016-07-01

Zika virus (ZIKV) is causing an explosive outbreak of febrile disease in the Americas. There are no effective antiviral therapies or licensed vaccines for this virus, and mosquito control strategies have not been adequate to contain the virus. A promising candidate for arbovirus control and prevention relies on the introduction of the intracellular bacterium Wolbachia into Aedes aegypti mosquitoes. This primarily has been proposed as a tool to control dengue virus (DENV) transmission; however, evidence suggests Wolbachia infections confer protection for Ae. aegypti against other arboviruses. At present, it is unknown whether or not ZIKV can infect, disseminate, and be transmitted by Wolbachia-infected Ae. aegypti. Using Ae. aegypti infected with the wMel strain of Wolbachia that are being released in Medellin, Colombia, we report that these mosquitoes have reduced vector competence for ZIKV. These results support the use of Wolbachia biocontrol as a multivalent strategy against Ae. aegypti-transmitted viruses.

Molecular characterization of Wolbachia infection in bed bugs (Cimex lectularius collected from several localities in France

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Akhoundi Mohammad

2016-01-01

Full Text Available Wolbachia symbionts are maternally inherited intracellular bacteria that have been detected in numerous insects including bed bugs. The objective of this study, the first epidemiological study in Europe, was to screen Wolbachia infection among Cimex lectularius collected in the field, using PCR targeting the surface protein gene (wsp, and to compare obtained Wolbachia strains with those reported from laboratory colonies of C. lectularius as well as other Wolbachia groups. For this purpose, 284 bed bug specimens were caught and studied from eight different regions of France including the suburbs of Paris, Bouches-du-Rhône, Lot-et-Garonne, and five localities in Alpes-Maritimes. Among the samples, 166 were adults and the remaining 118 were considered nymphs. In all, 47 out of 118 nymphs (40% and 61 out of 166 adults (37% were found positive on wsp screening. Among the positive cases, 10 samples were selected randomly for sequencing. The sequences had 100% homology with wsp sequences belonging to the F-supergroup strains of Wolbachia. Therefore, we confirm the similarity of Wolbachia strains detected in this epidemiological study to Wolbachia spp. reported from laboratory colonies of C. lectularius.

Wolbachia-a foe for mosquitoes

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Nadipinayakanahalli Munikrishnappa Guruprasad

2014-02-01

Full Text Available Mosquitoes act as vectors for a wide range of viral and parasitic infectious diseases such as malaria, dengue, Chickungunya, lymphatic filariasis, Japanese encephalitis and West Nile virus in humans as well as in animals. Although a wide range of insecticides are used to control mosquitoes, it has only resulted in development of resistance to such insecticides. The evolution of insecticide resistance and lack of vaccines for many mosquito-borne diseases have made these arthropods highly harmful vectors. Recently, a novel approach to control mosquitoes by transinfection of life shortening maternally transmitted endo-symbiont Wolbachia wMelPop strain from fruitfly Drosophila into mosquito population has been developed by researchers. The wMelPop strain up-regulated the immune gene expression in mosquitoes thereby reducing the dengue and Chickungunya viral replication in Aedes aegypti, and also it significantly reduced the Plasmodium level in Anopheles gambiae. Here, we discuss the strategy of using Wolbachia in control of vector-borne diseases of mosquitoes.

The immune cellular effectors of terrestrial isopod Armadillidium vulgare: meeting with their invaders, Wolbachia.

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Frédéric Chevalier

2011-04-01

Full Text Available Most of crustacean immune responses are well described for the aquatic forms whereas almost nothing is known for the isopods that evolved a terrestrial lifestyle. The latter are also infected at a high prevalence with Wolbachia, an endosymbiotic bacterium which affects the host immune system, possibly to improve its transmission. In contrast with insect models, the isopod Armadillidium vulgare is known to harbor Wolbachia inside the haemocytes.In A. vulgare we characterized three haemocyte types (TEM, flow cytometry: the hyaline and semi-granular haemocytes were phagocytes, while semi-granular and granular haemocytes performed encapsulation. They were produced in the haematopoietic organs, from central stem cells, maturing as they moved toward the edge (TEM. In infected individuals, live Wolbachia (FISH colonized 38% of the haemocytes but with low, variable densities (6.45±0.46 Wolbachia on average. So far they were not found in hyaline haemocytes (TEM. The haematopoietic organs contained 7.6±0.7×10(3Wolbachia, both in stem cells and differentiating cells (FISH. While infected and uninfected one-year-old individuals had the same haemocyte density, in infected animals the proportion of granular haemocytes in particular decreased by one third (flow cytometry, Pearson's test = 12 822.98, df = 2, p<0.001.The characteristics of the isopod immune system fell within the range of those known from aquatic crustaceans. The colonization of the haemocytes by Wolbachia seemed to stand from the haematopoietic organs, which may act as a reservoir to discharge Wolbachia in the haemolymph, a known route for horizontal transfer. Wolbachia infection did not affect the haemocyte density, but the quantity of granular haemocytes decreased by one third. This may account for the reduced prophenoloxidase activity observed previously in these animals.

New insights into the evolution of Wolbachia infections in filarial nematodes inferred from a large range of screened species.

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Emanuele Ferri

Full Text Available Wolbachia are intriguing symbiotic endobacteria with a peculiar host range that includes arthropods and a single nematode family, the Onchocercidae encompassing agents of filariases. This raises the question of the origin of infection in filariae. Wolbachia infect the female germline and the hypodermis. Some evidences lead to the theory that Wolbachia act as mutualist and coevolved with filariae from one infection event: their removal sterilizes female filariae; all the specimens of a positive species are infected; Wolbachia are vertically inherited; a few species lost the symbiont. However, most data on Wolbachia and filaria relationships derive from studies on few species of Onchocercinae and Dirofilariinae, from mammals.We investigated the Wolbachia distribution testing 35 filarial species, including 28 species and 7 genera and/or subgenera newly screened, using PCR, immunohistochemical staining, whole mount fluorescent analysis, and cocladogenesis analysis. (i Among the newly screened Onchocercinae from mammals eight species harbour Wolbachia but for some of them, bacteria are absent in the hypodermis, or in variable density. (ii Wolbachia are not detected in the pathological model Monanema martini and in 8, upon 9, species of Cercopithifilaria. (iii Supergroup F Wolbachia is identified in two newly screened Mansonella species and in Cercopithifilaria japonica. (iv Type F Wolbachia infect the intestinal cells and somatic female genital tract. (v Among Oswaldofilariinae, Waltonellinae and Splendidofilariinae, from saurian, anuran and bird respectively, Wolbachia are not detected.The absence of Wolbachia in 63% of onchocercids, notably in the ancestral Oswaldofilariinae estimated 140 mya old, the diverse tissues or specimens distribution, and a recent lateral transfer in supergroup F Wolbachia, modify the current view on the role and evolution of the endosymbiont and their hosts. Further genomic analyses on some of the newly sampled species

Vector competence of Malaysian Aedes albopictus with and without Wolbachia to four dengue virus serotypes.

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Joanne, Sylvia; Vythilingam, Indra; Teoh, Boon-Teong; Leong, Cherng-Shii; Tan, Kim-Kee; Wong, Meng-Li; Yugavathy, Nava; AbuBakar, Sazaly

2017-09-01

To determine the susceptibility status of Aedes albopictus with and without Wolbachia to the four dengue virus serotypes. Two newly colonised colonies of Ae. albopictus from the wild were used for the study. One colony was naturally infected with Wolbachia while in the other Wolbachia was removed by tetracycline treatment. Both colonies were orally infected with dengue virus-infected fresh blood meal. Dengue virus load was measured using quantitative RT-PCR at four-time intervals in the salivary glands, midguts and ovaries. Wolbachia did not significantly affect Malaysian Ae. albopictus dengue infection or the dissemination rate for all four dengue virus serotypes. Malaysian Ae. albopictus had the highest replication kinetics for DENV-1 and the highest salivary gland and midgut infection rate for DENV-4. Wolbachia, which naturally exists in Malaysian Ae. albopictus, does not significantly affect dengue virus replication. Malaysian Ae. albopictus is susceptible to dengue virus infections and capable of transmitting dengue virus, especially DENV-1 and DENV-4. Removal of Wolbachia from Malaysian Ae. albopictus would not reduce their susceptibility status. © 2017 John Wiley & Sons Ltd.

Increased cell motility and invasion upon knockdown of lipolysis stimulated lipoprotein receptor (LSR) in SW780 bladder cancer cells

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Herbsleb, Malene; Birkenkamp-Demtroder, Karin; Thykjaer, Thomas

2008-01-01

Mechanisms underlying the malignant development in bladder cancer are still not well understood. Lipolysis stimulated lipoprotein receptor (LSR) has previously been found to be upregulated by P53. Furthermore, we have previously found LSR to be differentially expressed in bladder cancer. Here we...... investigated the role of LSR in bladder cancer....

Effects of Doxycycline on gene expression in Wolbachia and Brugia malayi adult female worms in vivo

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Rao Ramakrishna U

2012-02-01

Full Text Available Abstract Background Most filarial nematodes contain Wolbachia symbionts. The purpose of this study was to examine the effects of doxycycline on gene expression in Wolbachia and adult female Brugia malayi. Methods Brugia malayi infected gerbils were treated with doxycycline for 6-weeks. This treatment largely cleared Wolbachia and arrested worm reproduction. RNA recovered from treated and control female worms was labeled by random priming and hybridized to the Version 2- filarial microarray to obtain expression profiles. Results and discussion Results showed significant changes in expression for 200 Wolbachia (29% of Wolbachia genes with expression signals in untreated worms and 546 B. malayi array elements after treatment. These elements correspond to known genes and also to novel genes with unknown biological functions. Most differentially expressed Wolbachia genes were down-regulated after treatment (98.5%. In contrast, doxycycline had a mixed effect on B. malayi gene expression with many more genes being significantly up-regulated after treatment (85% of differentially expressed genes. Genes and processes involved in reproduction (gender-regulated genes, collagen, amino acid metabolism, ribosomal processes, and cytoskeleton were down-regulated after doxycycline while up-regulated genes and pathways suggest adaptations for survival in response to stress (energy metabolism, electron transport, anti-oxidants, nutrient transport, bacterial signaling pathways, and immune evasion. Conclusions Doxycycline reduced Wolbachia and significantly decreased bacterial gene expression. Wolbachia ribosomes are believed to be the primary biological target for doxycycline in filarial worms. B. malayi genes essential for reproduction, growth and development were also down-regulated; these changes are consistent with doxycycline effects on embryo development and reproduction. On the other hand, many B. malayi genes involved in energy production, electron

Wolbachia age-sex-specific density in Aedes albopictus: a host evolutionary response to cytoplasmic incompatibility?

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Pablo Tortosa

2010-03-01

Full Text Available Wolbachia bacteria have invaded many arthropod species by inducing Cytoplasmic Incompatibility (CI. These symbionts represent fascinating objects of study for evolutionary biologists, but also powerful potential biocontrol agents. Here, we assess the density dynamics of Wolbachia infections in males and females of the mosquito Aedes albopitcus, an important vector of human pathogens, and interpret the results within an evolutionary framework.Wolbachia densities were measured in natural populations and in age controlled mosquitoes using quantitative PCR. We show that the density dynamics of the wAlbA Wolbachia strain infecting Aedes albopictus drastically differ between males and females, with a very rapid decay of infection in males only.Theory predicts that Wolbachia and its hosts should cooperate to improve the transmission of infection to offspring, because only infected eggs are protected from the effects of CI. However, incompatible matings effectively lower the fertility of infected males, so that selection acting on the host genome should tend to reduce the expression of CI in males, for example, by reducing infection density in males before sexual maturation. The rapid decay of one Wolbachia infection in Aedes albopictus males, but not in females, is consistent with this prediction. We suggest that the commonly observed reduction in CI intensity with male age reflects a similar evolutionary process. Our results also highlight the importance of monitoring infection density dynamics in both males and females to assess the efficiency of Wolbachia-based control strategies.

First record of Wolbachia in South American terrestrial isopods: prevalence and diversity in two species of Balloniscus (Crustacea, Oniscidea

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Mauricio Pereira Almerão

2012-01-01

Full Text Available Wolbachia are endosymbiotic bacteria that commonly infect arthropods, inducing certain phenotypes in their hosts. So far, no endemic South American species of terrestrial isopods have been investigated for Wolbachia infection. In this work, populations from two species of Balloniscus (B. sellowii and B. glaber were studied through a diagnostic PCR assay. Fifteen new Wolbachia 16S rDNA sequences were detected. Wolbachia found in both species were generally specific to one population, and five populations hosted two different Wolbachia 16S rDNA sequences. Prevalence was higher in B. glaber than in B. sellowii, but uninfected populations could be found in both species. Wolbachia strains from B. sellowii had a higher genetic variation than those isolated from B. glaber. AMOVA analyses showed that most of the genetic variance was distributed among populations of each species rather than between species, and the phylogenetic analysis suggested that Wolbachia strains from Balloniscus cluster within Supergroup B, but do not form a single monophyletic clade, suggesting multiple infections for this group. Our results highlight the importance of studying Wolbachia prevalence and genetic diversity in Neotropical species and suggest that South American arthropods may harbor a great number of diverse strains, providing an interesting model to investigate the evolution of Wolbachia and its hosts.

Wolbachia infect ovaries in the course of their maturation: last minute passengers and priority travellers?

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Lise-Marie Genty

Full Text Available Wolbachia are widespread endosymbiotic bacteria of arthropods and nematodes. Studies on such models suggest that Wolbachia's remarkable aptitude to infect offspring may rely on a re-infection of ovaries from somatic tissues instead of direct cellular segregation between oogonia and oocytes. In the terrestrial isopod Armadillidium vulgare, Wolbachia are vertically transmitted to the host offspring, even though ovary cells are cyclically renewed. Using Fluorescence in situ hybridization (FISH, we showed that the proportion of infected oocytes increased in the course of ovary and oocyte maturation, starting with 31.5% of infected oocytes only. At the end of ovary maturation, this proportion reached 87.6% for the most mature oocytes, which is close to the known transmission rate to offspring. This enrichment can be explained by a secondary acquisition of the bacteria by oocytes (Wolbachia can be seen as last minute passengers and/or by a preferential selection of oocytes infected with Wolbachia (as priority travellers.

The modulation of the symbiont/host interaction between Wolbachia pipientis and Aedes fluviatilis embryos by glycogen metabolism.

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Mariana da Rocha Fernandes

Full Text Available Wolbachia pipientis, a maternally transmitted bacterium that colonizes arthropods, may affect the general aspects of insect physiology, particularly reproduction. Wolbachia is a natural endosymbiont of Aedes fluviatilis, whose effects in embryogenesis and reproduction have not been addressed so far. In this context, we investigated the correlation between glucose metabolism and morphological alterations during A. fluviatilis embryo development in Wolbachia-positive (W+ and Wolbachia-negative (W- mosquito strains. While both strains do not display significant morphological and larval hatching differences, larger differences were observed in hexokinase activity and glycogen contents during early and mid-stages of embryogenesis, respectively. To investigate if glycogen would be required for parasite-host interaction, we reduced Glycogen Synthase Kinase-3 (GSK-3 levels in adult females and their eggs by RNAi. GSK-3 knock-down leads to embryonic lethality, lower levels of glycogen and total protein and Wolbachia reduction. Therefore, our results suggest that the relationship between A. fluviatilis and Wolbachia may be modulated by glycogen metabolism.

Various Wolbachia genotypes differently influence host Drosophila dopamine metabolism and survival under heat stress conditions.

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Gruntenko, Nataly Е; Ilinsky, Yury Yu; Adonyeva, Natalya V; Burdina, Elena V; Bykov, Roman A; Menshanov, Petr N; Rauschenbach, Inga Yu

2017-12-28

One of the most widespread prokaryotic symbionts of invertebrates is the intracellular bacteria of Wolbachia genus which can be found in about 50% of insect species. Wolbachia causes both parasitic and mutualistic effects on its host that include manipulating the host reproductive systems in order to increase their transmission through the female germline, and increasing the host fitness. One of the mechanisms, promoting adaptation in biological organisms, is a non-specific neuroendocrine stress reaction. In insects, this reaction includes catecholamines, dopamine, serotonin and octopamine, which act as neurotransmitters, neuromodulators and neurohormones. The level of dopamine metabolism correlates with heat stress resistance in Drosophila adults. To examine Wolbachia effect on Drosophila survival under heat stress and dopamine metabolism we used five strains carrying the nuclear background of interbred Bi90 strain and cytoplasmic backgrounds with different genotype variants of Wolbachia (produced by 20 backcrosses of Bi90 males with appropriate source of Wolbachia). Non-infected Bi90 strain (treated with tetracycline for 3 generations) was used as a control group. We demonstrated that two of five investigated Wolbachia variants promote changes in Drosophila heat stress resistance and activity of enzymes that produce and degrade dopamine, alkaline phosphatase and dopamine-dependent arylalkylamine N-acetyltransferase. What is especially interesting, wMelCS genotype of Wolbachia increases stress resistance and the intensity of dopamine metabolism, whereas wMelPop strain decreases them. wMel, wMel2 and wMel4 genotypes of Wolbachia do not show any effect on the survival under heat stress or dopamine metabolism. L-DOPA treatment, known to increase the dopamine content in Drosophila, levels the difference in survival under heat stress between all studied groups. The genotype of symbiont determines the effect that the symbiont has on the stress resistance of the host

A novel approach to eliminate Wolbachia infections in Nasonia vitripennis revealed different antibiotic resistance between two bacterial strains.

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Liu, Hai-Yang; Wang, Yan-Kun; Zhi, Cong-Cong; Xiao, Jin-Hua; Huang, Da-Wei

2014-06-01

Wolbachia are widespread in insects and can manipulate host reproduction. Nasonia vitripennis is a widely studied organism with a very high prevalence of Wolbachia infection. To study the effect of Wolbachia infection in Nasonia spp., it is important to obtain noninfected individuals by artificial methods. Current methods that employ sugar water-containing antibiotics can successfully eliminate Wolbachia from the parasitic wasps; however, treatment of at least three generations is required. Here, we describe a novel, feasible, and effective approach to eliminate Wolbachia from N. vitripennis by feeding fly pupae continuously offering antibiotics to Nasonia populations, which shortened the time to eliminate the pathogens to two generations. Additionally, the Wolbachia Uni and CauB strains have obviously different rifampicin-resistance abilities, which is a previously unknown phenomenon. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

Dynamic Wolbachia prevalence in Acromyrmex leaf‐cutting ants: potential for a nutritional symbiosis

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Andersen, S. B.; Boye, Mette; Nash, D. R.

2012-01-01

Wolbachia are renowned as reproductive parasites, but their phenotypic effects in eusocial insects are not well understood. We used a combination of qrt‐PCR, fluorescence in situ hybridization and laser scanning confocal microscopy to evaluate the dynamics of Wolbachia infections in the leaf‐cutting...

The Genomic Architecture of Novel Simulium damnosum Wolbachia Prophage Sequence Elements and Implications for Onchocerciasis Epidemiology

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James L. Crainey

2017-05-01

Full Text Available Research interest in Wolbachia is growing as new discoveries and technical advancements reveal the public health importance of both naturally occurring and artificial infections. Improved understanding of the Wolbachia bacteriophages (WOs WOcauB2 and WOcauB3 [belonging to a sub-group of four WOs encoding serine recombinases group 1 (sr1WOs], has enhanced the prospect of novel tools for the genetic manipulation of Wolbachia. The basic biology of sr1WOs, including host range and mode of genomic integration is, however, still poorly understood. Very few sr1WOs have been described, with two such elements putatively resulting from integrations at the same Wolbachia genome loci, about 2 kb downstream from the FtsZ cell-division gene. Here, we characterize the DNA sequence flanking the FtsZ gene of wDam, a genetically distinct line of Wolbachia isolated from the West African onchocerciasis vector Simulium squamosum E. Using Roche 454 shot-gun and Sanger sequencing, we have resolved >32 kb of WO prophage sequence into three contigs representing three distinct prophage elements. Spanning ≥36 distinct WO open reading frame gene sequences, these prophage elements correspond roughly to three different WO modules: a serine recombinase and replication module (sr1RRM, a head and base-plate module and a tail module. The sr1RRM module contains replication genes and a Holliday junction recombinase and is unique to the sr1 group WOs. In the extreme terminal of the tail module there is a SpvB protein homolog—believed to have insecticidal properties and proposed to have a role in how Wolbachia parasitize their insect hosts. We propose that these wDam prophage modules all derive from a single WO genome, which we have named here sr1WOdamA1. The best-match database sequence for all of our sr1WOdamA1-predicted gene sequences was annotated as of Wolbachia or Wolbachia phage sourced from an arthropod. Clear evidence of exchange between sr1WOdamA1 and other Wolbachia

Molecular subgrouping of Wolbachia and bacteriophage WO ...

Indian Academy of Sciences (India)

2011-12-16

Dec 16, 2011 ... 1Department of Biological Sciences, School of Natural Science, Jnanabharathi Campus, Bangalore University, ... but are also found to provide fitness benefits to their hosts ..... Wolbachia and virus protection in insects.

The diversity and evolution of Wolbachia ankyrin repeat domain genes.

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Stefanos Siozios

Full Text Available Ankyrin repeat domain-encoding genes are common in the eukaryotic and viral domains of life, but they are rare in bacteria, the exception being a few obligate or facultative intracellular Proteobacteria species. Despite having a reduced genome, the arthropod strains of the alphaproteobacterium Wolbachia contain an unusually high number of ankyrin repeat domain-encoding genes ranging from 23 in wMel to 60 in wPip strain. This group of genes has attracted considerable attention for their astonishing large number as well as for the fact that ankyrin proteins are known to participate in protein-protein interactions, suggesting that they play a critical role in the molecular mechanism that determines host-Wolbachia symbiotic interactions. We present a comparative evolutionary analysis of the wMel-related ankyrin repeat domain-encoding genes present in different Drosophila-Wolbachia associations. Our results show that the ankyrin repeat domain-encoding genes change in size by expansion and contraction mediated by short directly repeated sequences. We provide examples of intra-genic recombination events and show that these genes are likely to be horizontally transferred between strains with the aid of bacteriophages. These results confirm previous findings that the Wolbachia genomes are evolutionary mosaics and illustrate the potential that these bacteria have to generate diversity in proteins potentially involved in the symbiotic interactions.

Kaempferol stimulates gene expression of low-density lipoprotein receptor through activation of Sp1 in cultured hepatocytes

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Ochiai, Ayasa; Miyata, Shingo; Iwase, Masamori; Shimizu, Makoto; Inoue, Jun; Sato, Ryuichiro

2016-01-01

A high level of plasma low-density lipoprotein (LDL) cholesterol is considered a risk factor for atherosclerosis. Because the hepatic LDL receptor (LDLR) is essential for clearing plasma LDL cholesterol, activation of LDLR is a promising therapeutic target for patients with atherosclerotic disease. Here we demonstrated how the flavonoid kaempferol stimulated the gene expression and activity of LDLR in HepG2 cells. The kaempferol-mediated stimulation of LDLR gene expression was completely inhibited by knockdown of Sp1 gene expression. Treatment of HepG2 cells with kaempferol stimulated the recruitment of Sp1 to the promoter region of the LDLR gene, as well as the phosphorylation of Sp1 on Thr-453 and Thr-739. Moreover, these kaempferol-mediated processes were inhibited in the presence of U0126, an ERK pathway inhibitor. These results suggest that kaempferol may increase the activity of Sp1 through stimulation of Sp1 phosphorylation by ERK1/2 and subsequent induction of LDLR expression and activity. PMID:27109240

Short- and long-term evolutionary dynamics of bacterial insertion sequences: insights from Wolbachia endosymbionts.

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Cerveau, Nicolas; Leclercq, Sébastien; Leroy, Elodie; Bouchon, Didier; Cordaux, Richard

2011-01-01

Transposable elements (TE) are one of the major driving forces of genome evolution, raising the question of the long-term dynamics underlying their evolutionary success. Long-term TE evolution can readily be reconstructed in eukaryotes, thanks to many degraded copies constituting genomic fossil records of past TE proliferations. By contrast, bacterial genomes usually experience high sequence turnover and short TE retention times, thereby obscuring ancient TE evolutionary patterns. We found that Wolbachia bacterial genomes contain 52-171 insertion sequence (IS) TEs. IS account for 11% of Wolbachia wRi, which is one of the highest IS genomic coverage reported in prokaryotes to date. We show that many IS groups are currently expanding in various Wolbachia genomes and that IS horizontal transfers are frequent among strains, which can explain the apparent synchronicity of these IS proliferations. Remarkably, >70% of Wolbachia IS are nonfunctional. They constitute an unusual bacterial IS genomic fossil record providing direct empirical evidence for a long-term IS evolutionary dynamics following successive periods of intense transpositional activity. Our results show that comprehensive IS annotations have the potential to provide new insights into prokaryote TE evolution and, more generally, prokaryote genome evolution. Indeed, the identification of an important IS genomic fossil record in Wolbachia demonstrates that IS elements are not always of recent origin, contrary to the conventional view of TE evolution in prokaryote genomes. Our results also raise the question whether the abundance of IS fossils is specific to Wolbachia or it may be a general, albeit overlooked, feature of prokaryote genomes.

Geography has a greater effect than Wolbachia infection on population genetic structure in the spider mite, Tetranychus pueraricola.

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Chen, Y-T; Zhang, Y-K; Du, W-X; Jin, P-Y; Hong, X-Y

2016-10-01

Wolbachia is an intracellular symbiotic bacterium that infects various spider mite species and is associated with alterations in host reproduction, which indicates the potential role in mite evolution. However, studies of Wolbachia infections in the spider mite Tetranychus pueraricola, a major agricultural pest, are limited. Here, we used multilocus sequence typing to determine Wolbachia infection status and examined the relationship between Wolbachia infection status and mitochondrial diversity in T. pueraricola from 12 populations in China. The prevalence of Wolbachia ranged from 2.8 to 50%, and three strains (wTpue1, wTpue2, and wTpue3) were identified. We also found double infections (wTpue1 + wTpue3) within the same individuals. Furthermore, the wTpue1 strain caused weak cytoplasmic incompatibility (CI) (egg hatchability ~55%), whereas another widespread strain, wTpue3, did not induce CI. There was no reduction in mitochondrial DNA (mtDNA) or nuclear DNA diversity among infected individuals, and mtDNA haplotypes did not correspond to specific Wolbachia strains. Phylogenetic analysis and analysis of molecular variance revealed that the distribution of mtDNA and nuclear DNA haplotypes were significantly associated with geography. These findings indicate that Wolbachia infection in T. pueraricola is complex, but T. pueraricola genetic differentiation likely resulted from substantial geographic isolation.

Presence of extensive Wolbachia symbiont insertions discovered in the genome of its host Glossina morsitans morsitans.

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Corey Brelsfoard

2014-04-01

Full Text Available Tsetse flies (Glossina spp. are the cyclical vectors of Trypanosoma spp., which are unicellular parasites responsible for multiple diseases, including nagana in livestock and sleeping sickness in humans in Africa. Glossina species, including Glossina morsitans morsitans (Gmm, for which the Whole Genome Sequence (WGS is now available, have established symbiotic associations with three endosymbionts: Wigglesworthia glossinidia, Sodalis glossinidius and Wolbachia pipientis (Wolbachia. The presence of Wolbachia in both natural and laboratory populations of Glossina species, including the presence of horizontal gene transfer (HGT events in a laboratory colony of Gmm, has already been shown. We herein report on the draft genome sequence of the cytoplasmic Wolbachia endosymbiont (cytWol associated with Gmm. By in silico and molecular and cytogenetic analysis, we discovered and validated the presence of multiple insertions of Wolbachia (chrWol in the host Gmm genome. We identified at least two large insertions of chrWol, 527,507 and 484,123 bp in size, from Gmm WGS data. Southern hybridizations confirmed the presence of Wolbachia insertions in Gmm genome, and FISH revealed multiple insertions located on the two sex chromosomes (X and Y, as well as on the supernumerary B-chromosomes. We compare the chrWol insertions to the cytWol draft genome in an attempt to clarify the evolutionary history of the HGT events. We discuss our findings in light of the evolution of Wolbachia infections in the tsetse fly and their potential impacts on the control of tsetse populations and trypanosomiasis.

Mission Accomplished? We Need a Guide to the 'Post Release' World of Wolbachia for Aedes-borne Disease Control.

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Ritchie, Scott A; van den Hurk, Andrew F; Smout, Michael J; Staunton, Kyran M; Hoffmann, Ary A

2018-03-01

Historically, sustained control of Aedes aegypti, the vector of dengue, chikungunya, yellow fever, and Zika viruses, has been largely ineffective. Subsequently, two novel 'rear and release' control strategies utilizing mosquitoes infected with Wolbachia are currently being developed and deployed widely. In the incompatible insect technique, male Aedes mosquitoes, infected with Wolbachia, suppress populations through unproductive mating. In the transinfection strategy, both male and female Wolbachia-infected Ae. aegypti mosquitoes rapidly infect the wild population with Wolbachia, blocking virus transmission. It is critical to monitor the long-term stability of Wolbachia in host populations, and also the ability of this bacterium to continually inhibit virus transmission. Ongoing release and monitoring programs must be future-proofed should political support weaken when these vectors are successfully controlled. Copyright © 2017 Elsevier Ltd. All rights reserved.

Asymmetrical reinforcement and Wolbachia infection in Drosophila.

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John Jaenike

2006-10-01

Full Text Available Reinforcement refers to the evolution of increased mating discrimination against heterospecific individuals in zones of geographic overlap and can be considered a final stage in the speciation process. One the factors that may affect reinforcement is the degree to which hybrid matings result in the permanent loss of genes from a species' gene pool. Matings between females of Drosophila subquinaria and males of D. recens result in high levels of offspring mortality, due to interspecific cytoplasmic incompatibility caused by Wolbachia infection of D. recens. Such hybrid inviability is not manifested in matings between D. recens females and D. subquinaria males. Here we ask whether the asymmetrical hybrid inviability is associated with a corresponding asymmetry in the level of reinforcement. The geographic ranges of D. recens and D. subquinaria were found to overlap across a broad belt of boreal forest in central Canada. Females of D. subquinaria from the zone of sympatry exhibit much stronger levels of discrimination against males of D. recens than do females from allopatric populations. In contrast, such reproductive character displacement is not evident in D. recens, consistent with the expected effects of unidirectional cytoplasmic incompatibility. Furthermore, there is substantial behavioral isolation within D. subquinaria, because females from populations sympatric with D. recens discriminate against allopatric conspecific males, whereas females from populations allopatric with D. recens show no discrimination against any conspecific males. Patterns of general genetic differentiation among populations are not consistent with patterns of behavioral discrimination, which suggests that the behavioral isolation within D. subquinaria results from selection against mating with Wolbachia-infected D. recens. Interspecific cytoplasmic incompatibility may contribute not only to post-mating isolation, an effect already widely recognized, but also to

Wolbachia infection does not alter attraction of the mosquito Aedes (Stegomyia) aegypti to human odours

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Turley, A.P.; Smallegange, R.C.; Takken, W.; Zalucki, M.P.; O'Neill, S.L.; McGraw, E.A.

2014-01-01

The insect endosymbiont Wolbachia pipientis (Rickettsiales: Rickettsiaceae) is undergoing field trials around the world to determine if it can reduce transmission of dengue virus from the mosquito Stegomyia aegypti to humans. Two different Wolbachia strains have been released to date. The primary

Survey of endosymbionts in the Diaphorina citri metagenome and assembly of a Wolbachia wDi draft genome.

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Surya Saha

Full Text Available Diaphorina citri (Hemiptera: Psyllidae, the Asian citrus psyllid, is the insect vector of Ca. Liberibacter asiaticus, the causal agent of citrus greening disease. Sequencing of the D. citri metagenome has been initiated to gain better understanding of the biology of this organism and the potential roles of its bacterial endosymbionts. To corroborate candidate endosymbionts previously identified by rDNA amplification, raw reads from the D. citri metagenome sequence were mapped to reference genome sequences. Results of the read mapping provided the most support for Wolbachia and an enteric bacterium most similar to Salmonella. Wolbachia-derived reads were extracted using the complete genome sequences for four Wolbachia strains. Reads were assembled into a draft genome sequence, and the annotation assessed for the presence of features potentially involved in host interaction. Genome alignment with the complete sequences reveals membership of Wolbachia wDi in supergroup B, further supported by phylogenetic analysis of FtsZ. FtsZ and Wsp phylogenies additionally indicate that the Wolbachia strain in the Florida D. citri isolate falls into a sub-clade of supergroup B, distinct from Wolbachia present in Chinese D. citri isolates, supporting the hypothesis that the D. citri introduced into Florida did not originate from China.

Survey of endosymbionts in the Diaphorina citri metagenome and assembly of a Wolbachia wDi draft genome.

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Saha, Surya; Hunter, Wayne B; Reese, Justin; Morgan, J Kent; Marutani-Hert, Mizuri; Huang, Hong; Lindeberg, Magdalen

2012-01-01

Diaphorina citri (Hemiptera: Psyllidae), the Asian citrus psyllid, is the insect vector of Ca. Liberibacter asiaticus, the causal agent of citrus greening disease. Sequencing of the D. citri metagenome has been initiated to gain better understanding of the biology of this organism and the potential roles of its bacterial endosymbionts. To corroborate candidate endosymbionts previously identified by rDNA amplification, raw reads from the D. citri metagenome sequence were mapped to reference genome sequences. Results of the read mapping provided the most support for Wolbachia and an enteric bacterium most similar to Salmonella. Wolbachia-derived reads were extracted using the complete genome sequences for four Wolbachia strains. Reads were assembled into a draft genome sequence, and the annotation assessed for the presence of features potentially involved in host interaction. Genome alignment with the complete sequences reveals membership of Wolbachia wDi in supergroup B, further supported by phylogenetic analysis of FtsZ. FtsZ and Wsp phylogenies additionally indicate that the Wolbachia strain in the Florida D. citri isolate falls into a sub-clade of supergroup B, distinct from Wolbachia present in Chinese D. citri isolates, supporting the hypothesis that the D. citri introduced into Florida did not originate from China.

Wolbachia Blocks Currently Circulating Zika Virus Isolates in Brazilian Aedes aegypti Mosquitoes

OpenAIRE

Dutra, Heverton Leandro Carneiro; Rocha, Marcele Neves; Dias, Fernando Braga Stehling; Mansur, Simone Brutman; Caragata, Eric Pearce; Moreira, Luciano Andrade

2016-01-01

Summary The recent association of Zika virus with cases of microcephaly has sparked a global health crisis and highlighted the need for mechanisms to combat the Zika vector, Aedes aegypti mosquitoes. Wolbachia pipientis, a bacterial endosymbiont of insect, has recently garnered attention as a mechanism for arbovirus control. Here we report that Aedes aegypti harboring Wolbachia are highly resistant to infection with two currently circulating Zika virus isolates from the recent Brazilian epide...

Impact of Wolbachia on infection with chikungunya and yellow fever viruses in the mosquito vector Aedes aegypti.

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Andrew F van den Hurk

Full Text Available Incidence of disease due to dengue (DENV, chikungunya (CHIKV and yellow fever (YFV viruses is increasing in many parts of the world. The viruses are primarily transmitted by Aedes aegypti, a highly domesticated mosquito species that is notoriously difficult to control. When transinfected into Ae. aegypti, the intracellular bacterium Wolbachia has recently been shown to inhibit replication of DENVs, CHIKV, malaria parasites and filarial nematodes, providing a potentially powerful biocontrol strategy for human pathogens. Because the extent of pathogen reduction can be influenced by the strain of bacterium, we examined whether the wMel strain of Wolbachia influenced CHIKV and YFV infection in Ae. aegypti. Following exposure to viremic blood meals, CHIKV infection and dissemination rates were significantly reduced in mosquitoes with the wMel strain of Wolbachia compared to Wolbachia-uninfected controls. However, similar rates of infection and dissemination were observed in wMel infected and non-infected Ae. aegypti when intrathoracic inoculation was used to deliver virus. YFV infection, dissemination and replication were similar in wMel-infected and control mosquitoes following intrathoracic inoculations. In contrast, mosquitoes with the wMelPop strain of Wolbachia showed at least a 10(4 times reduction in YFV RNA copies compared to controls. The extent of reduction in virus infection depended on Wolbachia strain, titer and strain of the virus, and mode of exposure. Although originally proposed for dengue biocontrol, our results indicate a Wolbachia-based strategy also holds considerable promise for YFV and CHIKV suppression.

Localization and dynamics of Wolbachia infection in Asian citrus psyllid Diaphorina citri, the insect vector of the causal pathogens of Huanglongbing.

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Ren, Su-Li; Li, Yi-Han; Ou, Da; Guo, Yan-Jun; Qureshi, Jawwad A; Stansly, Philip A; Qiu, Bao-Li

2018-03-23

Wolbachia is a group of intracellular bacteria that infect a wide range of arthropods including the Asian citrus psyllid (ACP), Diaphorina citri Kuwayama. This insect is the vector of Candidatus Liberibacter asiaticus (CLas), the causal pathogen of Huanglongbing or citrus greening disease. Here, we investigated the localization pattern and infection dynamics of Wolbachia in different developmental stages of ACP. Results revealed that all developmental stages of ACP including egg, 1st-5th instar nymphs, and adults of both gender were infected with Wolbachia. FISH visualization of an ACP egg showed that Wolbachia moved from the egg stalk of newly laid eggs to a randomly distributed pattern throughout the egg prior to hatching. The infection rate varied between nymphal instars. The titers of Wolbachia in fourth and fifth instar nymphs were significantly higher than those in the first and second instar nymphs. Wolbachia were scattered in all nymphal stages, but with highest intensity in the U-shaped bacteriome located in the abdomen of the nymph. Wolbachia was confined to two symmetrical organizations in the abdomen of newly emerged female and male adults. The potential mechanisms of Wolbachia infection dynamics are discussed. © 2018 The Authors. MicrobiologyOpen published by John Wiley & Sons Ltd.

Wolbachia and dengue virus infection in the mosquito Aedes fluviatilis (Diptera: Culicidae.

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Jéssica Barreto Lopes Silva

Full Text Available Dengue represents a serious threat to human health, with billions of people living at risk of the disease. Wolbachia pipientis is a bacterial endosymbiont common to many insect species. Wolbachia transinfections in mosquito disease vectors have great value for disease control given the bacterium's ability to spread into wild mosquito populations, and to interfere with infections of pathogens, such as dengue virus. Aedes fluviatilis is a mosquito with a widespread distribution in Latin America, but its status as a dengue vector has not been clarified. Ae. fluviatilis is also naturally infected by the wFlu Wolbachia strain, which has been demonstrated to enhance infection with the avian malarial parasite Plasmodium gallinaceum. We performed experimental infections of Ae. fluviatilis with DENV-2 and DENV-3 isolates from Brazil via injection or oral feeding to provide insight into its competence for the virus. We also examined the effect of the native Wolbachia infection on the virus using a mosquito line where the wFlu infection had been cleared by antibiotic treatment. Through RT-qPCR, we observed that Ae. fluviatilis could become infected with both viruses via either method of infection, although at a lower rate than Aedes aegypti, the primary dengue vector. We then detected DENV-2 and DENV-3 in the saliva of injected mosquitoes, and observed that injection of DENV-3-infected saliva produced subsequent infections in naïve Ae. aegypti. However, across our data we observed no difference in prevalence of infection and viral load between Wolbachia-infected and -uninfected mosquitoes, suggesting that there is no effect of wFlu on dengue virus. Our results highlight that Ae. fluviatilis could potentially serve as a dengue vector under the right circumstances, although further testing is required to determine if this occurs in the field.

New criteria for selecting the origin of DNA replication in Wolbachia and closely related bacteria

DEFF Research Database (Denmark)

Ioannidis, Panagiotis; Dunning Hotopp, Julie C; Sapountzis, Panagiotis

2007-01-01

, the origin of DNA replication (ori) regions were identified in silico for Wolbachia strains and eleven other related bacteria belonging to Ehrlichia, Anaplasma, and Rickettsia genera. These features include DnaA-, CtrA- and IHF-binding sites as well as the flanking genes in C. crescentus. The Wolbachia ori...

Dynamic Wolbachia prevalence in Acromyrmex leaf-cutting ants: potential for a nutritional symbiosis.

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Andersen, S B; Boye, M; Nash, D R; Boomsma, J J

2012-07-01

Wolbachia are renowned as reproductive parasites, but their phenotypic effects in eusocial insects are not well understood. We used a combination of qrt-PCR, fluorescence in situ hybridization and laser scanning confocal microscopy to evaluate the dynamics of Wolbachia infections in the leaf-cutting ant Acromyrmex octospinosus across developmental stages of sterile workers. We confirm that workers are infected with one or two widespread wsp genotypes of Wolbachia, show that colony prevalence is always 100% and characterize two rare recombinant genotypes. One dominant genotype is always present and most abundant, whereas another only proliferates in adult workers of some colonies and is barely detectable in larvae and pupae. An explanation may be that Wolbachia genotypes compete for host resources in immature stages while adult tissues provide substantially more niche space. Tissue-specific prevalence of the two genotypes differs, with the rarer genotype being over-represented in the adult foregut and thorax muscles. Both genotypes occur extracellularly in the foregut, suggesting an unknown mutualistic function in worker ant nutrition. Both genotypes are also abundant in the faecal fluid of the ants, suggesting that they may have extended functional phenotypes in the fungus garden that the ants manure with their own faeces. © 2012 The Authors. Journal of Evolutionary Biology © 2012 European Society For Evolutionary Biology.

PRESENCIA DE Wolbachia y Leishmania EN UNA POBLACION DE Lutzomyia evansi PRESENTE EN LA COSTA CARIBE DE COLOMBIA

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Rafael J. Vivero-Gómez

2016-07-01

Full Text Available Lutzomyia evansi es importante en salud pública por su participación en la trasmisión de la leishmaniasis visceral y cutánea en la costa caribe de Colombia. Diversos estudios se han desarrollado sobre la poblaciones naturales de Lutzomyia evansi, sin embargo pocos estudios han explorado en profundidad la detección de microorganismos simbióticos (ej. Wolbachia y de manera simultánea la presencia de Leishmania sp.. El endosimbionte Wolbachia ha sido propuesto en la actualidad como control biológico de insectos vectores de diversas enfermedades tropicales. En el presente estudio el ADN de tres especies del género Lutzomyia colectadas en el municipio de Ovejas (Departamento de Sucre fue evaluado para detectar la infección natural por la bacteria Wolbachia y la presencia de parásitos del género Leishmania. El ADN total de 176 individuos adultos y 34 inmaduros (larvas y pupas de Lu. evansi, fue utilizado para evaluar la detección de Wolbachia mediante amplificación por PCR del gen WSP (Proteína Mayor de la Superficie de Wolbachia y la infección por Leishmania mediante amplificación por PCR de segmentos de los genes HPSN70 (Proteína de Choque Térmico. Se encontró un grupo de machos infectado de forma natural por Wolbachia y nueve grupos de hembras con infección natural por Leishmania, todos pertenecientes a Lutzomyia evansi. El análisis filogenético de la secuencia del gen WSP de Wolbachia indica la ubicación de la cepa detectada dentro del supergrupo B (haplogrupo wLeva y su relación con haplotipos previamente reportados de Lutzomyia evansi y Lutzomya dubitans. Una región de 418 pb del gen HSP-70N fue secuenciada y mostró similaridad con secuencias de Leishmania luego de realizar el análisis en BlastN. Se confirma la presencia de Wolbachia en poblaciones silvestres de machos de L. evansi y la infección natural por Leishmania spp. en hembras de la misma especie cuya infección por Wolbachia resulto negativa.

I. Lipid metabolism stimulated by altered intracellular calcium in cultured fibroblasts. II. Regulation of the activity of rat adipose tissue lipoprotein lipase

International Nuclear Information System (INIS)

Chang Wang, Huei-Hsiang Lisa.

1988-01-01

The cell killing process of 3T3 Swiss mouse fibroblasts stimulated by Ca 2+ plus A23187, a Ca 2+ ionophore has been studied. The aim of this research is to understand the biochemical mechanism of this process, i.e, to elucidate the step involved and to characterize the enzymes involved with each steps in the lipid metabolism stimulated in cultured fibroblasts undergoing a toxic death response. Parallel 3T3 cultures biosynthetically labeled with lipid precursors were examined under Ca 2+ -mediated killing conditions. Labeled lipids were extracted and analyzed by thin-layer chromatography and autoradiography. Evidence for activation of a phosphatidylinositol-specific phospholipase C has been obtained in injured 3T3 cells labeled with [ 3 H]glycerol and [ 3 H]inositol. To simplify the system for studying the lipoprotein lipase reaction, our laboratory prepared the chromophore containing a substrate: 1,2-dipalmitoyl-3-β-2-furylacryloyltriacylglycerol (DPFATG). By using this artificial lipid we could readily investigate the lipoprotein lipase reactions, since the absorbance change directly represents the hydrolysis of the chromophoric side chain of the substrate

Feminizing Wolbachia: a transcriptomics approach with insights on the immune response genes in Armadillidium vulgare

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Chevalier Frédéric

2012-01-01

Full Text Available Abstract Background Wolbachia are vertically transmitted bacteria known to be the most widespread endosymbiont in arthropods. They induce various alterations of the reproduction of their host, including feminization of genetic males in isopod crustaceans. In the pill bug Armadillidium vulgare, the presence of Wolbachia is also associated with detrimental effects on host fertility and lifespan. Deleterious effects have been demonstrated on hemocyte density, phenoloxidase activity, and natural hemolymph septicemia, suggesting that infected individuals could have defective immune capacities. Since nothing is known about the molecular mechanisms involved in Wolbachia-A. vulgare interactions and its secondary immunocompetence modulation, we developed a transcriptomics strategy and compared A. vulgare gene expression between Wolbachia-infected animals (i.e., “symbiotic” animals and uninfected ones (i.e., “asymbiotic” animals as well as between animals challenged or not challenged by a pathogenic bacteria. Results Since very little genetic data is available on A. vulgare, we produced several EST libraries and generated a total of 28 606 ESTs. Analyses of these ESTs revealed that immune processes were over-represented in most experimental conditions (responses to a symbiont and to a pathogen. Considering canonical crustacean immune pathways, these genes encode antimicrobial peptides or are involved in pathogen recognition, detoxification, and autophagy. By RT-qPCR, we demonstrated a general trend towards gene under-expression in symbiotic whole animals and ovaries whereas the same gene set tends to be over-expressed in symbiotic immune tissues. Conclusion This study allowed us to generate the first reference transcriptome ever obtained in the Isopoda group and to identify genes involved in the major known crustacean immune pathways encompassing cellular and humoral responses. Expression of immune-related genes revealed a modulation of host

High virulence of Wolbachia after host switching: when autophagy hurts.

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Winka Le Clec'h

Full Text Available Wolbachia are widespread endosymbionts found in a large variety of arthropods. While these bacteria are generally transmitted vertically and exhibit weak virulence in their native hosts, a growing number of studies suggests that horizontal transfers of Wolbachia to new host species also occur frequently in nature. In transfer situations, virulence variations can be predicted since hosts and symbionts are not adapted to each other. Here, we describe a situation where a Wolbachia strain (wVulC becomes a pathogen when transfected from its native terrestrial isopod host species (Armadillidium vulgare to another species (Porcellio d. dilatatus. Such transfer of wVulC kills all recipient animals within 75 days. Before death, animals suffer symptoms such as growth slowdown and nervous system disorders. Neither those symptoms nor mortalities were observed after injection of wVulC into its native host A. vulgare. Analyses of wVulC's densities in main organs including Central Nervous System (CNS of both naturally infected A. vulgare and transfected P. d. dilatatus and A. vulgare individuals revealed a similar pattern of host colonization suggesting an overall similar resistance of both host species towards this bacterium. However, for only P. d. dilatatus, we observed drastic accumulations of autophagic vesicles and vacuoles in the nerve cells and adipocytes of the CNS from individuals infected by wVulC. The symptoms and mortalities could therefore be explained by this huge autophagic response against wVulC in P. d. dilatatus cells that is not triggered in A. vulgare. Our results show that Wolbachia (wVulC can lead to a pathogenic interaction when transferred horizontally into species that are phylogenetically close to their native hosts. This change in virulence likely results from the autophagic response of the host, strongly altering its tolerance to the symbiont and turning it into a deadly pathogen.

Molecular detection and identification of Wolbachia in three species of the genus Lutzomyia on the Colombian Caribbean coast.

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Vivero, Rafael José; Cadavid-Restrepo, Gloria; Herrera, Claudia Ximena Moreno; Soto, Sandra I Uribe

2017-02-28

The hematophagous habits of insects belonging to the genus Lutzomyia (Diptera: Psychodidae), as well as their role as biological vectors of Leishmania species, make their presence an indication of infection risk. In the present study, seven species of Lutzomyia were identified and screened for natural infections with Wolbachia. Collection of sand flies was done in an endemic focus of leishmaniasis on the Colombian Caribbean coast (Department of Sucre, Ovejas municipality). DNA collected from Lutzomyia species was evaluated with PCR for wsp gene amplification to screen for bacterial infection. Endosymbiotic Wolbachia was found in three species: Lutzomyia c. cayennensis, Lutzomyia dubitans and Lutzomyia evansi. Two Wolbachia strains (genotypes) were found in Lutzomyia spp. These genotypes were previously unknown in dipteran insects. The wLev strain was found in Lutzomyia dubitans, L. c. cayennensis and L. evansi and the wLcy strain was found only in L. c. cayennensis. Genetic analysis indicated that the Wolbachia strains wLcy and wLev belong to the B Supergroup. This study provides evidence of infections of more than one strain of Wolbachia in L. c. cayennensis.

Wolbachia, una pandemia con posibilidades

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Marcela S. RODRIGUERO

2013-01-01

Full Text Available La infección causada por Wolbachia es la más extendida entre los animales. La capacidad de esta bacteria para manipular la reproducción de sus hospedadores la posicionan en el centro de la biología de los organismos, influyendo en procesos tan capitales como la determinación del sexo, el ciclo celular, la formación y extinción de especies y el comportamiento de artrópodos entre los que se cuentan varias plagas y vectores de enfermedades. Cualidades tales como la herencia vertical de Wolbachia, la velocidad a la que se propaga en las poblaciones que afecta, la capacidad de bloquear la actividad patogénica de diversos microorganismos o de acortar el ciclo de vida de sus hospedadores la señalan como un potencial instrumento para el control de poblaciones de insec - tos y nematodos perjudiciales. ¿Cuáles son las posibilidades que nos ofrece esta pandemia? En la presente contribución se presenta una revisión de los aspectos fundamen - tales de esta infección y sus implicancias prácticas para el manejo de insectos plaga. Esta revisión está basada en el simposio del mismo nombre acontecido en el VIII Congreso Argentino de Entomología.

The diversity of reproductive parasites among arthropods: Wolbachia do not walk alone

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Zhou Liqin

2008-06-01

Full Text Available Abstract Background Inherited bacteria have come to be recognised as important components of arthropod biology. In addition to mutualistic symbioses, a range of other inherited bacteria are known to act either as reproductive parasites or as secondary symbionts. Whilst the incidence of the α-proteobacterium Wolbachia is relatively well established, the current knowledge of other inherited bacteria is much weaker. Here, we tested 136 arthropod species for a range of inherited bacteria known to demonstrate reproductive parasitism, sampling each species more intensively than in past surveys. Results The inclusion of inherited bacteria other than Wolbachia increased the number of infections recorded in our sample from 33 to 57, and the proportion of species infected from 22.8% to 32.4%. Thus, whilst Wolbachia remained the dominant inherited bacterium, it alone was responsible for around half of all inherited infections of the bacteria sampled, with members of the Cardinium, Arsenophonus and Spiroplasma ixodetis clades each occurring in 4% to 7% of all species. The observation that infection was sometimes rare within host populations, and that there was variation in presence of symbionts between populations indicates that our survey will itself underscore incidence. Conclusion This extensive survey demonstrates that at least a third of arthropod species are infected by a diverse assemblage of maternally inherited bacteria that are likely to strongly influence their hosts' biology, and indicates an urgent need to establish the nature of the interaction between non-Wolbachia bacteria and their hosts.

Cholesterol synthesis by human fetal hepatocytes: effect of lipoproteins

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Carr, B.R.; Simpson, E.R.

1984-01-01

The purpose of the present investigation was to determine the effect of various lipoproteins on the rate of cholesterol synthesis of human fetal liver cells maintained in culture. This was accomplished by measuring the rate of incorporation of tritium from tritiated water or carbon 14-labeled acetate into cholesterol in human fetal liver cells. Optimal conditions for each assay were determined. When human fetal liver cells were maintained in the presence of low-density lipoprotein, cholesterol synthesis was inhibited in a concentration-dependent fashion. Intermediate--density lipoprotein and very-low-density lipoprotein also suppressed cholesterol synthesis in human fetal liver cells. In contrast, high-density lipoprotein stimulated cholesterol synthesis in human fetal liver cells. The results of the present as well as our previous investigations suggest that multiple interrelationships exist between fetal liver cholesterol synthesis and lipoprotein-cholesterol utilization by the human fetal adrenal gland and that these processes serve to regulate the lipoprotein-cholesterol levels in fetal plasma

How does competition among wild type mosquitoes influence the performance of Aedes aegypti and dissemination of Wolbachia pipientis?

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Suellen de Oliveira

2017-10-01

Full Text Available Wolbachia has been deployed in several countries to reduce transmission of dengue, Zika and chikungunya viruses. During releases, Wolbachia-infected females are likely to lay their eggs in local available breeding sites, which might already be colonized by local Aedes sp. mosquitoes. Therefore, there is an urgent need to estimate the deleterious effects of intra and interspecific larval competition on mosquito life history traits, especially on the duration of larval development time, larval mortality and adult size.Three different mosquito populations were used: Ae. aegypti infected with Wolbachia (wMelBr strain, wild Ae. aegypti and wild Ae. albopictus. A total of 21 treatments explored intra and interspecific larval competition with varying larval densities, species proportions and food levels. Each treatment had eight replicates with two distinct food levels: 0.25 or 0.50 g of Chitosan and fallen avocado leaves. Overall, overcrowding reduced fitness correlates of the three populations. Ae. albopictus larvae presented lower larval mortality, shorter development time to adult and smaller wing sizes than Ae. aegypti. The presence of Wolbachia had a slight positive effect on larval biology, since infected individuals had higher survivorship than uninfected Ae. aegypti larvae.In all treatments, Ae. albopictus outperformed both wild Ae. aegypti and the Wolbachia-infected group in larval competition, irrespective of larval density and the amount of food resources. The major force that can slow down Wolbachia invasion is the population density of wild mosquitoes. Given that Ae. aegypti currently dominates in Rio, in comparison with Ae. albopictus frequency, additional attention must be given to the population density of Ae. aegypti during releases to increase the likelihood of Wolbachia invasion.

Wolbachia Infection Reduces Blood-Feeding Success in the Dengue Fever Mosquito, Aedes aegypti

OpenAIRE

Turley, Andrew P.; Moreira, Luciano A.; O'Neill, Scott L.; McGraw, Elizabeth A.

2009-01-01

BACKGROUND: The mosquito Aedes aegypti was recently transinfected with a life-shortening strain of the endosymbiont Wolbachia pipientis (wMelPop) as the first step in developing a biocontrol strategy for dengue virus transmission. In addition to life-shortening, the wMelPop-infected mosquitoes also exhibit increased daytime activity and metabolic rates. Here we sought to quantify the blood-feeding behaviour of Wolbachia-infected females as an indicator of any virulence or energetic drain asso...

Effects of Larval Nutrition on Wolbachia-Based Dengue Virus Interference in Aedes aegypti (Diptera: Culicidae).

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Kho, Elise A; Hugo, Leon E; Lu, Guangjin; Smith, David D; Kay, Brian H

2016-07-01

In order to assess the broad-scale applicability of field releases of Wolbachia for the biological control of insect-transmitted diseases, we determined the relationship between the larval diet of Aedes aegypti L. mosquitoes infected with Wolbachia strains and their susceptibility to dengue virus (DENV) infection via intrathoracic injection and oral inoculation. Larvae were reared on diets that varied in the quantity of food which had the effect of modifying development time and adult body size. Wolbachia wMel infection was associated with highly significant reductions in dengue serotype 2 (DENV-2) infection rates of between 80 and 97.5% following intrathoracic injection of adults emerging from three diet levels. Reductions were 100% in two diet level treatments following oral inoculation. Similarly, wMelPop infection was associated with highly significant reductions in DENV-2 infection rates of between 95 and 100% for intrathoracic injection and 97.5 and 100% for oral inoculation across diet level treatments. Larval diet level had no significant effect on DENV-2 infection rates in the presence of Wolbachia infection in mosquitoes that were intrathoracically injected with the virus. This indicates that the effectiveness of Wolbachia on vector competence disruption within Ae. aegypti is unlikely to be compromised by variable larval nutrition in field settings. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Effects of co-occurring Wolbachia and Spiroplasma endosymbionts on the Drosophila immune response against insect pathogenic and non-pathogenic bacteria.

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Shokal, Upasana; Yadav, Shruti; Atri, Jaishri; Accetta, Julia; Kenney, Eric; Banks, Katherine; Katakam, Akash; Jaenike, John; Eleftherianos, Ioannis

2016-02-09

Symbiotic interactions between microbes and animals are common in nature. Symbiotic organisms are particularly common in insects and, in some cases, they may protect their hosts from pathogenic infections. Wolbachia and Spiroplasma endosymbionts naturally inhabit various insects including Drosophila melanogaster fruit flies. Therefore, this symbiotic association is considered an excellent model to investigate whether endosymbiotic bacteria participate in host immune processes against certain pathogens. Here we have investigated whether the presence of Wolbachia alone or together with Spiroplasma endosymbionts in D. melanogaster adult flies affects the immune response against the virulent insect pathogen Photorhabdus luminescens and against non-pathogenic Escherichia coli bacteria. We found that D. melanogaster flies carrying no endosymbionts, those carrying both Wolbachia and Spiroplasma, and those containing Wolbachia only had similar survival rates after infection with P. luminescens or Escherichia coli bacteria. However, flies carrying both endosymbionts or Wolbachia only contained higher numbers of E. coli cells at early time-points post infection than flies without endosymbiotic bacteria. Interestingly, flies containing Wolbachia only had lower titers of this endosymbiont upon infection with the pathogen P. luminescens than uninfected flies of the same strain. We further found that the presence of Wolbachia and Spiroplasma in D. melanogaster up-regulated certain immune-related genes upon infection with P. luminescens or E. coli bacteria, but it failed to alter the phagocytic ability of the flies toward E. coli inactive bioparticles. Our results suggest that the presence of Wolbachia and Spiroplasma in D. melanogaster can modulate immune signaling against infection by certain insect pathogenic and non-pathogenic bacteria. Results from such studies are important for understanding the molecular basis of the interactions between endosymbiotic bacteria of insects

Double trouble: combined action of meiotic drive and Wolbachia feminization in Eurema butterflies.

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Kern, Peter; Cook, James M; Kageyama, Daisuke; Riegler, Markus

2015-05-01

Arthropod sex ratios can be manipulated by a diverse range of selfish genetic elements, including maternally inherited Wolbachia bacteria. Feminization by Wolbachia is rare but has been described for Eurema mandarina butterflies. In this species, some phenotypic and functional females, thought to be ZZ genetic males, are infected with a feminizing Wolbachia strain, wFem. Meanwhile, heterogametic WZ females are not infected with wFem. Here, we establish a quantitative PCR assay allowing reliable sexing in three Eurema species. Against expectation, all E. mandarina females, including wFem females, had only one Z chromosome that was paternally inherited. Observation of somatic interphase nuclei confirmed that W chromatin was absent in wFem females, but present in females without wFem. We conclude that the sex bias in wFem lines is due to meiotic drive (MD) that excludes the maternal Z and thus prevents formation of ZZ males. Furthermore, wFem lines may have lost the W chromosome or harbour a dysfunctional version, yet rely on wFem for female development; removal of wFem results in all-male offspring. This is the first study that demonstrates an interaction between MD and Wolbachia feminization, and it highlights endosymbionts as potentially confounding factors in MD of sex chromosomes. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

Identification and phylogenetic analysis of Dirofilaria ursi (Nematoda: Filarioidea) from Wisconsin black bears (Ursus americanus) and its Wolbachia endosymbiont.

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Michalski, Michelle L; Bain, Odile; Fischer, Kerstin; Fischer, Peter U; Kumar, Sanjay; Foster, Jeremy M

2010-04-01

Dirofilaria ursi is a filarial nematode of American black bears (Ursus americanus Pallas, 1780) that is vectored by black flies (Simuliidae) in many parts of the United States. In northwestern Wisconsin, the prevalence of microfilaremic bears during the fall hunting season was 21% (n = 47). Unsheathed blood microfilariae from Wisconsin bears possess characters consistent with the original description of D. ursi, as do adult worms observed histologically and grossly. Immunohistochemistry was used to identify the Wolbachia endosymbiont in the hypodermis and lateral cords of an adult female D. ursi. Amplification of wsp, gatB, coxA, fbpA, and ftsZ bacterial sequences from parasite DNA confirmed the presence of Wolbachia, and molecular phylogenetic analysis of the Wolbachia ftsZ gene groups the endosymbiont with Wolbachia from D. immitis and D. repens. Phylogenetic analysis of D. ursi 5s rDNA sequence confirms the morphological observations grouping this parasite as a member of Dirofilaria, and within the Dirofilaria - Onchocerca clade of filarial nematodes. This is the first report of Wolbachia characterization and molecular phylogeny information for D. ursi.

Wolbachia Blocks Viral Genome Replication Early in Infection without a Transcriptional Response by the Endosymbiont or Host Small RNA Pathways.

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Stephanie M Rainey

2016-04-01

Full Text Available The intracellular endosymbiotic bacterium Wolbachia can protect insects against viral infection, and is being introduced into mosquito populations in the wild to block the transmission of arboviruses that infect humans and are a major public health concern. To investigate the mechanisms underlying this antiviral protection, we have developed a new model system combining Wolbachia-infected Drosophila melanogaster cell culture with the model mosquito-borne Semliki Forest virus (SFV; Togaviridae, Alphavirus. Wolbachia provides strong antiviral protection rapidly after infection, suggesting that an early stage post-infection is being blocked. Wolbachia does appear to have major effects on events distinct from entry, assembly or exit as it inhibits the replication of an SFV replicon transfected into the cells. Furthermore, it causes a far greater reduction in the expression of proteins from the 3' open reading frame than the 5' non-structural protein open reading frame, indicating that it is blocking the replication of viral RNA. Further to this separation of the replicase proteins and viral RNA in transreplication assays shows that uncoupling of viral RNA and replicase proteins does not overcome Wolbachia's antiviral activity. This further suggests that replicative processes are disrupted, such as translation or replication, by Wolbachia infection. This may occur by Wolbachia mounting an active antiviral response, but the virus did not cause any transcriptional response by the bacterium, suggesting that this is not the case. Host microRNAs (miRNAs have been implicated in protection, but again we found that host cell miRNA expression was unaffected by the bacterium and neither do our findings suggest any involvement of the antiviral siRNA pathway. We conclude that Wolbachia may directly interfere with early events in virus replication such as translation of incoming viral RNA or RNA transcription, and this likely involves an intrinsic (as opposed to

Antibiotic treatment leads to the elimination of Wolbachia endosymbionts and sterility in the diplodiploid collembolan Folsomia candida

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Kingcombe Rachel

2009-08-01

Full Text Available Abstract Background Wolbachia is an extremely widespread bacterial endosymbiont of arthropods and nematodes that causes a variety of reproductive peculiarities. Parthenogenesis is one such peculiarity but it has been hypothesised that this phenomenon may be functionally restricted to organisms that employ haplodiploid sex determination. Using two antibiotics, tetracycline and rifampicin, we attempted to eliminate Wolbachia from the diplodiploid host Folsomia candida, a species of springtail which is a widely used study organism. Results Molecular assays confirmed that elimination of Wolbachia was successfully achieved through continuous exposure of populations (over two generations and several weeks to rifampicin administered as 2.7% dry weight of their yeast food source. The consequence of this elimination was total sterility of all individuals, despite the continuation of normal egg production. Conclusion Microbial endosymbionts play an obligatory role in the reproduction of their diplodiploid host, most likely one in which the parthenogenetic process is facilitated by Wolbachia. A hitherto unknown level of host-parasite interdependence is thus recorded.

Detection of Wolbachia (Alphaproteobacteria: rickettsiales in three species of terrestrial isopods (crustacea: isopoda: oniscidea in Brazil

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Bianca Laís Zimmermann

2012-06-01

Full Text Available Terrestrial isopods are widely infected with Wolbachia. However, little is known about the presence of bacteria in the Neotropical species. The objective of this study was to test the hypothesis of presence of Wolbachia infection in the native species of terrestrial isopods, Atlantoscia floridana and Circoniscus bezzii, and in the introduced species Burmoniscus meeusei.

Wolbachia endosymbiont infection in two Indian butterflies and ...

Indian Academy of Sciences (India)

The maternally inherited obligate bacteria Wolbachia is known to infect various lepidopteran insects. However, so far only a few butterfly species harbouring this bacterium have been thoroughly studied. The current study aims to identify the infection status of these bacteria in some of the commonly found butterfly species in ...

Wolbachia-induced loss of male fertility is likely related to branch chain amino acid biosynthesis and iLvE in Laodelphax striatellus.

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Ju, Jia-Fei; Hoffmann, Ary A; Zhang, Yan-Kai; Duan, Xing-Zhi; Guo, Yan; Gong, Jun-Tao; Zhu, Wen-Chao; Hong, Xiao-Yue

2017-06-01

Wolbachia are endosymbionts that infect many species of arthropods and nematodes. Wolbachia-induced cytoplasmic incompatibility (CI) is the most common phenotype in affected hosts, involving embryonic lethality in crosses between Wolbachia-infected males and uninfected females. The molecular mechanisms underlying this phenomenon are currently unclear. Here we examine the molecular correlates of the Wolbachia infection in Laodelphax striatellus (Fallén), an important rice pest, where embryonic lethality is strong and almost complete. We compared the gene expression of 4-day-old Wolbachia-infected and uninfected L. striatellus testes to identify candidate genes for paternal-effect embryonic lethality induction. Based on microarray analysis, iLvE was the most down-regulated gene; this gene mediates branched-chain amino acid (BCAA) biosynthesis and participates in many processes related to reproductive performance. After knocking down iLvE by RNAi in uninfected male L. striatellus, male fertility was reduced, leading to a decrease in embryo hatching rates, but fertility was rescued in crosses between these males and Wolbachia-infected females. Removal of BCAA in chemically-defined diets of uninfected males also led to a loss of male fertility. Low amino acid nutrition may enhance exposure time of sperm to Wolbachia in the testes to affect adult reproduction in L. striatellus by reducing the number of sperm transferred per mating by males. These results indicate that Wolbachia may decrease male fertility in L. striatellus by acting on iLvE, a key factor of BCAA biosynthesis, and delaying sperm maturation. Copyright © 2017 Elsevier Ltd. All rights reserved.

The expression of one ankyrin pk2 allele of the WO prophage is correlated with the Wolbachia feminizing effect in isopods

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Pichon Samuel

2012-04-01

Full Text Available Abstract Background The maternally inherited α-Proteobacteria Wolbachia pipientis is an obligate endosymbiont of nematodes and arthropods, in which they induce a variety of reproductive alterations, including Cytoplasmic Incompatibility (CI and feminization. The genome of the feminizing wVulC Wolbachia strain harboured by the isopod Armadillidium vulgare has been sequenced and is now at the final assembly step. It contains an unusually high number of ankyrin motif-containing genes, two of which are homologous to the phage-related pk1 and pk2 genes thought to contribute to the CI phenotype in Culex pipiens. These genes encode putative bacterial effectors mediating Wolbachia-host protein-protein interactions via their ankyrin motifs. Results To test whether these Wolbachia homologs are potentially involved in altering terrestrial isopod reproduction, we determined the distribution and expression of both pk1 and pk2 genes in the 3 Wolbachia strains that induce CI and in 5 inducing feminization of their isopod hosts. Aside from the genes being highly conserved, we found a substantial copy number variation among strains, and that is linked to prophage diversity. Transcriptional analyses revealed expression of one pk2 allele (pk2b2 only in the feminizing Wolbachia strains of isopods. Conclusions These results reveal the need to investigate the functions of Wolbachia ankyrin gene products, in particular those of Pk2, and their host targets with respect to host sex manipulation.

Local introduction and heterogeneous spatial spread of dengue-suppressing Wolbachia through an urban population of Aedes aegypti.

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Tom L Schmidt

2017-05-01

Full Text Available Dengue-suppressing Wolbachia strains are promising tools for arbovirus control, particularly as they have the potential to self-spread following local introductions. To test this, we followed the frequency of the transinfected Wolbachia strain wMel through Ae. aegypti in Cairns, Australia, following releases at 3 nonisolated locations within the city in early 2013. Spatial spread was analysed graphically using interpolation and by fitting a statistical model describing the position and width of the wave. For the larger 2 of the 3 releases (covering 0.97 km2 and 0.52 km2, we observed slow but steady spatial spread, at about 100-200 m per year, roughly consistent with theoretical predictions. In contrast, the smallest release (0.11 km2 produced erratic temporal and spatial dynamics, with little evidence of spread after 2 years. This is consistent with the prediction concerning fitness-decreasing Wolbachia transinfections that a minimum release area is needed to achieve stable local establishment and spread in continuous habitats. Our graphical and likelihood analyses produced broadly consistent estimates of wave speed and wave width. Spread at all sites was spatially heterogeneous, suggesting that environmental heterogeneity will affect large-scale Wolbachia transformations of urban mosquito populations. The persistence and spread of Wolbachia in release areas meeting minimum area requirements indicates the promise of successful large-scale population transformation.

Staphylococcus aureus induces IL-8 expression through its lipoproteins in the human intestinal epithelial cell, Caco-2.

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Kang, Seok-Seong; Noh, Su Young; Park, Ok-Jin; Yun, Cheol-Heui; Han, Seung Hyun

2015-09-01

Staphylococcus aureus can cause the intestinal inflammatory diseases. However, little is known about the molecular mechanism of S. aureus infection in the intestine. In the present study, we investigated whether S. aureus could stimulate human intestinal epithelial cells triggering inflammation. When the human intestinal epithelial cell-line, Caco-2, and the primary colon cells were stimulated with ethanol-inactivated S. aureus, IL-8 expression was induced in a dose-dependent manner. The inactivated S. aureus preferentially stimulated Toll-like receptor (TLR) 2 rather than TLR4. Lipoproteins, lipoteichoic acid (LTA), and peptidoglycan (PGN) are considered as potential TLR2 ligands of S. aureus. Interestingly, S aureus lipoproteins and Pam2CSK4 mimicking Gram-positive bacterial lipoproteins, but not LTA and PGN of S. aureus, significantly induced IL-8 expression in Caco-2 cells. Furthermore, lipoprotein-deficient S. aureus mutant strain failed to induce IL-8 production. Collectively, these results suggest that S. aureus stimulates the human intestinal epithelial cells to induce the chemokine IL-8 production through its lipoproteins, potentially contributing the development of intestinal inflammation. Copyright © 2015 Elsevier Ltd. All rights reserved.

Serendipitous discovery of Wolbachia genomes in multiple Drosophila species.

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Salzberg, Steven L; Dunning Hotopp, Julie C; Delcher, Arthur L; Pop, Mihai; Smith, Douglas R; Eisen, Michael B; Nelson, William C

2005-01-01

The Trace Archive is a repository for the raw, unanalyzed data generated by large-scale genome sequencing projects. The existence of this data offers scientists the possibility of discovering additional genomic sequences beyond those originally sequenced. In particular, if the source DNA for a sequencing project came from a species that was colonized by another organism, then the project may yield substantial amounts of genomic DNA, including near-complete genomes, from the symbiotic or parasitic organism. By searching the publicly available repository of DNA sequencing trace data, we discovered three new species of the bacterial endosymbiont Wolbachia pipientis in three different species of fruit fly: Drosophila ananassae, D. simulans, and D. mojavensis. We extracted all sequences with partial matches to a previously sequenced Wolbachia strain and assembled those sequences using customized software. For one of the three new species, the data recovered were sufficient to produce an assembly that covers more than 95% of the genome; for a second species the data produce the equivalent of a 'light shotgun' sampling of the genome, covering an estimated 75-80% of the genome; and for the third species the data cover approximately 6-7% of the genome. The results of this study reveal an unexpected benefit of depositing raw data in a central genome sequence repository: new species can be discovered within this data. The differences between these three new Wolbachia genomes and the previously sequenced strain revealed numerous rearrangements and insertions within each lineage and hundreds of novel genes. The three new genomes, with annotation, have been deposited in GenBank.

The Potential Use of Wolbachia-Based Mosquito Biocontrol Strategies for Japanese Encephalitis.

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Claire L Jeffries

Full Text Available Japanese encephalitis virus (JEV is a zoonotic pathogen transmitted by the infectious bite of Culex mosquitoes. The virus causes the development of the disease Japanese encephalitis (JE in a small proportion of those infected, predominantly affecting children in eastern and southern Asia. Annual JE incidence estimates range from 50,000-175,000, with 25%-30% of cases resulting in mortality. It is estimated that 3 billion people live in countries in which JEV is endemic. The virus exists in an enzootic transmission cycle, with mosquitoes transmitting JEV between birds as reservoir hosts and pigs as amplifying hosts. Zoonotic infection occurs as a result of spillover events from the main transmission cycle. The reservoir avian hosts include cattle egrets, pond herons, and other species of water birds belonging to the family Ardeidae. Irrigated rice fields provide an ideal breeding ground for mosquitoes and attract migratory birds, maintaining the transmission of JEV. Although multiple vaccines have been developed for JEV, they are expensive and require multiple doses to maintain efficacy and immunity. As humans are a "dead-end" host for the virus, vaccination of the human population is unlikely to result in eradication. Therefore, vector control of the principal mosquito vector, Culex tritaeniorhynchus, represents a more promising strategy for reducing transmission. Current vector control strategies include intermittent irrigation of rice fields and space spraying of insecticides during outbreaks. However, Cx. Tritaeniorhynchus is subject to heavy exposure to pesticides in rice fields, and as a result, insecticide resistance has developed. In recent years, significant advancements have been made in the potential use of the bacterial endosymbiont Wolbachia for mosquito biocontrol. The successful transinfection of Wolbachia strains from Drosophila flies to Aedes (Stegomyia mosquitoes has resulted in the generation of "dengue-refractory" mosquito

Targeting the Wolbachia cell division protein FtsZ as a new approach for antifilarial therapy.

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Zhiru Li

2011-11-01

Full Text Available The use of antibiotics targeting the obligate bacterial endosymbiont Wolbachia of filarial parasites has been validated as an approach for controlling filarial infection in animals and humans. Availability of genomic sequences for the Wolbachia (wBm present in the human filarial parasite Brugia malayi has enabled genome-wide searching for new potential drug targets. In the present study, we investigated the cell division machinery of wBm and determined that it possesses the essential cell division gene ftsZ which was expressed in all developmental stages of B. malayi examined. FtsZ is a GTPase thereby making the protein an attractive Wolbachia drug target. We described the molecular characterization and catalytic properties of Wolbachia FtsZ. We also demonstrated that the GTPase activity was inhibited by the natural product, berberine, and small molecule inhibitors identified from a high-throughput screen. Furthermore, berberine was also effective in reducing motility and reproduction in B. malayi parasites in vitro. Our results should facilitate the discovery of selective inhibitors of FtsZ as a novel anti-symbiotic approach for controlling filarial infection. NOTE: The nucleotide sequences reported in this paper are available in GenBank™ Data Bank under the accession number wAlB-FtsZ (JN616286.

Wolbachia Protein TomO Targets nanos mRNA and Restores Germ Stem Cells in Drosophila Sex-lethal Mutants.

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Ote, Manabu; Ueyama, Morio; Yamamoto, Daisuke

2016-09-12

Wolbachia, endosymbiotic bacteria prevalent in invertebrates, manipulate their hosts in a variety of ways: they induce cytoplasmic incompatibility, male lethality, male-to-female transformation, and parthenogenesis. However, little is known about the molecular basis for host manipulation by these bacteria. In Drosophila melanogaster, Wolbachia infection makes otherwise sterile Sex-lethal (Sxl) mutant females capable of producing mature eggs. Through a functional genomic screen for Wolbachia genes with growth-inhibitory effects when expressed in cultured Drosophila cells, we identified the gene WD1278 encoding a novel protein we call toxic manipulator of oogenesis (TomO), which phenocopies some of the Wolbachia effects in Sxl mutant D. melanogaster females. We demonstrate that TomO enhances the maintenance of germ stem cells (GSCs) by elevating Nanos (Nos) expression via its interaction with nos mRNA, ultimately leading to the restoration of germ cell production in Sxl mutant females that are otherwise without GSCs. Copyright © 2016 Elsevier Ltd. All rights reserved.

Evolutionary Significance of Wolbachia-to-Animal Horizontal Gene Transfer: Female Sex Determination and the f Element in the Isopod Armadillidium vulgare.

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Cordaux, Richard; Gilbert, Clément

2017-07-21

An increasing number of horizontal gene transfer (HGT) events from bacteria to animals have been reported in the past years, many of which involve Wolbachia bacterial endosymbionts and their invertebrate hosts. Most transferred Wolbachia genes are neutrally-evolving fossils embedded in host genomes. A remarkable case of Wolbachia HGT for which a clear evolutionary significance has been demonstrated is the " f element", a nuclear Wolbachia insert involved in female sex determination in the terrestrial isopod Armadillidium vulgare . The f element represents an instance of bacteria-to-animal HGT that has occurred so recently that it was possible to infer the donor (feminizing Wolbachia closely related to the w VulC Wolbachia strain of A. vulgare ) and the mechanism of integration (a nearly complete genome inserted by micro-homology-mediated recombination). In this review, we summarize our current knowledge of the f element and discuss arising perspectives regarding female sex determination, unstable inheritance, population dynamics and the molecular evolution of the f element. Overall, the f element unifies three major areas in evolutionary biology: symbiosis, HGT and sex determination. Its characterization highlights the tremendous impact sex ratio distorters can have on the evolution of sex determination mechanisms and sex chromosomes in animals and plants.

Evolutionary Significance of Wolbachia-to-Animal Horizontal Gene Transfer: Female Sex Determination and the f Element in the Isopod Armadillidium vulgare

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Richard Cordaux

2017-07-01

Full Text Available An increasing number of horizontal gene transfer (HGT events from bacteria to animals have been reported in the past years, many of which involve Wolbachia bacterial endosymbionts and their invertebrate hosts. Most transferred Wolbachia genes are neutrally-evolving fossils embedded in host genomes. A remarkable case of Wolbachia HGT for which a clear evolutionary significance has been demonstrated is the “f element”, a nuclear Wolbachia insert involved in female sex determination in the terrestrial isopod Armadillidium vulgare. The f element represents an instance of bacteria-to-animal HGT that has occurred so recently that it was possible to infer the donor (feminizing Wolbachia closely related to the wVulC Wolbachia strain of A. vulgare and the mechanism of integration (a nearly complete genome inserted by micro-homology-mediated recombination. In this review, we summarize our current knowledge of the f element and discuss arising perspectives regarding female sex determination, unstable inheritance, population dynamics and the molecular evolution of the f element. Overall, the f element unifies three major areas in evolutionary biology: symbiosis, HGT and sex determination. Its characterization highlights the tremendous impact sex ratio distorters can have on the evolution of sex determination mechanisms and sex chromosomes in animals and plants.

From lab to field: the influence of urban landscapes on the invasive potential of Wolbachia in Brazilian Aedes aegypti mosquitoes.

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Heverton Leandro Carneiro Dutra

2015-04-01

Full Text Available The symbiotic bacterium Wolbachia is currently being trialled as a biocontrol agent in several countries to reduce dengue transmission. Wolbachia can invade and spread to infect all individuals within wild mosquito populations, but requires a high rate of maternal transmission, strong cytoplasmic incompatibility and low fitness costs in the host in order to do so. Additionally, extensive differences in climate, field-release protocols, urbanization level and human density amongst the sites where this bacterium has been deployed have limited comparison and analysis of Wolbachia's invasive potential.We examined key phenotypic effects of the wMel Wolbachia strain in laboratory Aedes aegypti mosquitoes with a Brazilian genetic background to characterize its invasive potential. We show that the wMel strain causes strong cytoplasmic incompatibility, a high rate of maternal transmission and has no evident detrimental effect on host fecundity or fertility. Next, to understand the effects of different urban landscapes on the likelihood of mosquito survival, we performed mark-release-recapture experiments using Wolbachia-uninfected Brazilian mosquitoes in two areas of Rio de Janeiro where Wolbachia will be deployed in the future. We characterized the mosquito populations in relation to the socio-demographic conditions at these sites, and at three other future release areas. We then constructed mathematical models using both the laboratory and field data, and used these to describe the influence of urban environmental conditions on the likelihood that the Wolbachia infection frequency could reach 100% following mosquito release. We predict successful invasion at all five field sites, however the conditions by which this occurs vary greatly between sites, and are strongly influenced by the size of the local mosquito population.Through analysis of laboratory, field and mathematical data, we show that the wMel strain of Wolbachia possesses the characteristics

The joint evolutionary histories of Wolbachia and mitochondria in Hypolimnas bolina

OpenAIRE

Roderick George K; Davies Neil; Dyson Emily A; Hornett Emily A; Duplouy Anne; Charlat Sylvain; Wedell Nina; Hurst Gregory DD

2009-01-01

Abstract Background The interaction between the Blue Moon butterfly, Hypolimnas bolina, and Wolbachia has attracted interest because of the high prevalence of male-killing achieved within the species, the ecological consequences of this high prevalence, the intensity of selection on the host to suppress the infection, and the presence of multiple Wolbachia infections inducing different phenotypes. We examined diversity in the co-inherited marker, mtDNA, and the partitioning of this between in...

Detection of Wolbachia in wild Tunisian populations of Ceratitis capitata

International Nuclear Information System (INIS)

Mimouni, Wafa

2009-01-01

For the pest management programmes, we used the Wolbavhia pipientis, this bacteria caused a hight sterility in the medfly. by the technique of molecular biology, we have detect the Wolbachia pipientis in the wild populations in Tunisia.

Replacing a native Wolbachia with a novel strain results in an increase in endosymbiont load and resistance to dengue virus in a mosquito vector.

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Guowu Bian

Full Text Available Wolbachia is a maternally transmitted endosymbiotic bacterium that is estimated to infect up to 65% of insect species. The ability of Wolbachia to both induce pathogen interference and spread into mosquito vector populations makes it possible to develop Wolbachia as a biological control agent for vector-borne disease control. Although Wolbachia induces resistance to dengue virus (DENV, filarial worms, and Plasmodium in mosquitoes, species like Aedes polynesiensis and Aedes albopictus, which carry native Wolbachia infections, are able to transmit dengue and filariasis. In a previous study, the native wPolA in Ae. polynesiensis was replaced with wAlbB from Ae. albopictus, and resulted in the generation of the transinfected "MTB" strain with low susceptibility for filarial worms. In this study, we compare the dynamics of DENV serotype 2 (DENV-2 within the wild type "APM" strain and the MTB strain of Ae. polynesiensis by measuring viral infection in the mosquito whole body, midgut, head, and saliva at different time points post infection. The results show that wAlbB can induce a strong resistance to DENV-2 in the MTB mosquito. Evidence also supports that this resistance is related to a dramatic increase in Wolbachia density in the MTB's somatic tissues, including the midgut and salivary gland. Our results suggests that replacement of a native Wolbachia with a novel infection could serve as a strategy for developing a Wolbachia-based approach to target naturally infected insects for vector-borne disease control.

Hindrances to bistable front propagation: application to Wolbachia invasion.

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Nadin, Grégoire; Strugarek, Martin; Vauchelet, Nicolas

2018-05-01

We study the biological situation when an invading population propagates and replaces an existing population with different characteristics. For instance, this may occur in the presence of a vertically transmitted infection causing a cytoplasmic effect similar to the Allee effect (e.g. Wolbachia in Aedes mosquitoes): the invading dynamics we model is bistable. We aim at quantifying the propagules (what does it take for an invasion to start?) and the invasive power (how far can an invading front go, and what can stop it?). We rigorously show that a heterogeneous environment inducing a strong enough population gradient can stop an invading front, which will converge in this case to a stable front. We characterize the critical population jump, and also prove the existence of unstable fronts above the stable (blocking) fronts. Being above the maximal unstable front enables an invading front to clear the obstacle and propagate further. We are particularly interested in the case of artificial Wolbachia infection, used as a tool to fight arboviruses.

Membrane receptors for very low density lipoprotein (VLDL) inhibitor of lymphocyte proliferation

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Yi, P.I.; Beck, G.; Zucker, S.

1981-01-01

Physiologic concentrations of human plasma very low density lipoproteins inhibit the DNA synthesis of lymphocytes stimulated by allogeneic cells or lectins. In this report reachers have compared the effects of isolated lipoproteins [very low density lipoproteins (VLDL), low density lipoproteins (LDL), and high density lipoproteins (HDL)] and lipoprotein-depleted plasma (LDP) on DNA synthesis by phytohemagglutinin-stimulated human lymphocytes. The relative potency for the inhibition of lymphocyte proliferation was VLDL greater than LDL greater than HDL greater than LDP. Fifty percent inhibition of DNA synthesis was observed at a VLDL protein concentration of 1.5--2.0 microgram/ml. Researchers have further demonstrated the presence of specific receptors for VLDL on human lymphocytes. Native VLDL was more effective than LDL in competing for 125I-VLDL binding sites. Subsequent to binding to lymphocytes, 125I-VLDL was internalized and degraded to acid-soluble products. Based on a Scatchard analysis of VLDL binding at 4 degrees C, the number of VLDL receptors per lymphocyte was estimated at 28,000 +/- 1300. Based on an estimated mean binding affinity for the VLDL receptor complex at half saturation of approximately 8.8 X 10(7) liter/mole, it is estimated that 91% of lymphocyte VLDL receptors are occupied at physiologic VLDL concentrations in blood. Although the immune regulatory role of plasma lipoproteins is uncertain, researchers suggest tha VLDL and LDL-In may maintain circulating blood lymphocytes in a nonproliferative state via their respective cell receptor mechanisms

Cloning and sequencing of wsp encoding gene fragments reveals a diversity of co-infecting Wolbachia strains in Acromyrmex leafcutter ants

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van Borm, S.; Wenseleers, T.; Billen, J.

2003-01-01

Acromyrmex insinuator hosted two additional infections. The multiple Wolbachia strains may influence the expression of reproductive conflicts in leafcutter ants, but the expected turnover of infections may make the cumulative effects on host ant reproduction complex. The additional Wolbachia infections......By sequencing part of the wsp gene of a series of clones, we detected an unusually high diversity of nine Wolbachia strains in queens of three species of leafcutter ants. Up to four strains co-occurred in a single ant. Most strains occurred in two clusters (InvA and InvB), but the social parasite...

Comparisons of host mitochondrial, nuclear and endosymbiont bacterial genes reveal cryptic fig wasp species and the effects of Wolbachia on host mtDNA evolution and diversity

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Feng Gui

2011-04-01

Full Text Available Abstract Background Figs and fig-pollinating wasp species usually display a highly specific one-to-one association. However, more and more studies have revealed that the "one-to-one" rule has been broken. Co-pollinators have been reported, but we do not yet know how they evolve. They may evolve from insect speciation induced or facilitated by Wolbachia which can manipulate host reproduction and induce reproductive isolation. In addition, Wolbachia can affect host mitochondrial DNA evolution, because of the linkage between Wolbachia and associated mitochondrial haplotypes, and thus confound host phylogeny based on mtDNA. Previous research has shown that fig wasps have the highest incidence of Wolbachia infection in all insect taxa, and Wolbachia may have great influence on fig wasp biology. Therefore, we look forward to understanding the influence of Wolbachia on mitochondrial DNA evolution and speciation in fig wasps. Results We surveyed 76 pollinator wasp specimens from nine Ficus microcarpa trees each growing at a different location in Hainan and Fujian Provinces, China. We found that all wasps were morphologically identified as Eupristina verticillata, but diverged into three clades with 4.22-5.28% mtDNA divergence and 2.29-20.72% nuclear gene divergence. We also found very strong concordance between E. verticillata clades and Wolbachia infection status, and the predicted effects of Wolbachia on both mtDNA diversity and evolution by decreasing mitochondrial haplotypes. Conclusions Our study reveals that the pollinating wasp E. verticillata on F. microcarpa has diverged into three cryptic species, and Wolbachia may have a role in this divergence. The results also indicate that Wolbachia strains infecting E. verticillata have likely resulted in selective sweeps on host mitochondrial DNA.

The joint evolutionary histories of Wolbachia and mitochondria in Hypolimnas bolina.

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Charlat, Sylvain; Duplouy, Anne; Hornett, Emily A; Dyson, Emily A; Davies, Neil; Roderick, George K; Wedell, Nina; Hurst, Gregory D D

2009-03-24

The interaction between the Blue Moon butterfly, Hypolimnas bolina, and Wolbachia has attracted interest because of the high prevalence of male-killing achieved within the species, the ecological consequences of this high prevalence, the intensity of selection on the host to suppress the infection, and the presence of multiple Wolbachia infections inducing different phenotypes. We examined diversity in the co-inherited marker, mtDNA, and the partitioning of this between individuals of different infection status, as a means to investigate the population biology and evolutionary history of the Wolbachia infections. Part of the mitochondrial COI gene was sequenced from 298 individuals of known infection status revealing ten different haplotypes. Despite very strong biological evidence that the sample represents a single species, the ten haplotypes did not fall within a monophyletic clade within the Hypolimnas genus, with one haplotype differing by 5% from the other nine. There were strong associations between infection status and mtDNA haplotype. The presence of wBol1 infection in association with strongly divergent haplotypes prompted closer examination of wBol1 genetic variation. This revealed the existence of two cryptic subtypes, wBol1a and wBol1b. The wBol1a infection, by far the most common, was in strict association with the single divergent mtDNA haplotype. The wBol1b infection was found with two haplotypes that were also observed in uninfected specimens. Finally, the wBol2 infection was associated with a large diversity of mtDNA haplotypes, most often shared with uninfected sympatric butterflies. This data overall supports the hypothesis that high prevalence of male-killing Wolbachia (wBol1) in H. bolina is associated with very high transmission efficiency rather than regular horizontal transmission. It also suggests this infection has undergone a recent selective sweep and was introduced in this species through introgression. In contrast, the sharing of

Accelerated microevolution in an outer membrane protein (OMP of the intracellular bacteria Wolbachia

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Russell Jacob A

2010-02-01

Full Text Available Abstract Background Outer membrane proteins (OMPs of Gram-negative bacteria are key players in the biology of bacterial-host interactions. However, while considerable attention has been given to OMPs of vertebrate pathogens, relatively little is known about the role of these proteins in bacteria that primarily infect invertebrates. One such OMP is found in the intracellular bacteria Wolbachia, which are widespread symbionts of arthropods and filarial nematodes. Recent experimental studies have shown that the Wolbachia surface protein (WSP can trigger host immune responses and control cell death programming in humans, suggesting a key role of WSP for establishment and persistence of the symbiosis in arthropods. Results Here we performed an analysis of 515 unique alleles found in 831 Wolbachia isolates, to investigate WSP structure, microevolution and population genetics. WSP shows an eight-strand transmembrane β-barrel structure with four extracellular loops containing hypervariable regions (HVRs. A clustering approach based upon patterns of HVR haplotype diversity was used to group similar WSP sequences and to estimate the relative contribution of mutation and recombination during early stages of protein divergence. Results indicate that although point mutations generate most of the new protein haplotypes, recombination is a predominant force triggering diversity since the very first steps of protein evolution, causing at least 50% of the total amino acid variation observed in recently diverged proteins. Analysis of synonymous variants indicates that individual WSP protein types are subject to a very rapid turnover and that HVRs can accommodate a virtually unlimited repertoire of peptides. Overall distribution of WSP across hosts supports a non-random association of WSP with the host genus, although extensive horizontal transfer has occurred also in recent times. Conclusions In OMPs of vertebrate pathogens, large recombination impact, positive

The heme biosynthetic pathway of the obligate Wolbachia endosymbiont of Brugia malayi as a potential anti-filarial drug target.

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Bo Wu

2009-07-01

Full Text Available Filarial parasites (e.g., Brugia malayi, Onchocerca volvulus, and Wuchereria bancrofti are causative agents of lymphatic filariasis and onchocerciasis, which are among the most disabling of neglected tropical diseases. There is an urgent need to develop macro-filaricidal drugs, as current anti-filarial chemotherapy (e.g., diethylcarbamazine [DEC], ivermectin and albendazole can interrupt transmission predominantly by killing microfilariae (mf larvae, but is less effective on adult worms, which can live for decades in the human host. All medically relevant human filarial parasites appear to contain an obligate endosymbiotic bacterium, Wolbachia. This alpha-proteobacterial mutualist has been recognized as a potential target for filarial nematode life cycle intervention, as antibiotic treatments of filarial worms harboring Wolbachia result in the loss of worm fertility and viability upon antibiotic treatments both in vitro and in vivo. Human trials have confirmed this approach, although the length of treatments, high doses required and medical counter-indications for young children and pregnant women warrant the identification of additional anti-Wolbachia drugs.Genome sequence analysis indicated that enzymes involved in heme biosynthesis might constitute a potential anti-Wolbachia target set. We tested different heme biosynthetic pathway inhibitors in ex vivo B. malayi viability assays and report a specific effect of N-methyl mesoporphyrin (NMMP, which targets ferrochelatase (FC, the last step. Our phylogenetic analysis indicates evolutionarily significant divergence between Wolbachia heme genes and their human homologues. We therefore undertook the cloning, overexpression and analysis of several enzymes of this pathway alongside their human homologues, and prepared proteins for drug targeting. In vitro enzyme assays revealed a approximately 600-fold difference in drug sensitivities to succinyl acetone (SA between Wolbachia and human 5

Regulation of hepatic lipase activity by sphingomyelin in plasma lipoproteins.

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Yang, Peng; Subbaiah, Papasani V

2015-10-01

Hepatic lipase (HL) is an important enzyme in the clearance of triacylglycerol (TAG) from the circulation, and has been proposed to have pro-atherogenic as well as anti-atherogenic properties. It hydrolyzes both phospholipids and TAG of lipoproteins, and its activity is negatively correlated with HDL levels. Although it is known that HL acts preferentially on HDL lipids, the basis for this specificity is not known, since it does not require any specific apoprotein for activity. In this study, we tested the hypothesis that sphingomyelin (SM), whose concentration is much higher in VLDL and LDL compared to HDL, is an inhibitor of HL, and that this could explain the lipoprotein specificity of the enzyme. The results presented show that the depletion of SM from normal lipoproteins activated the HL roughly in proportion to their SM content. SM depletion stimulated the hydrolysis of both phosphatidylcholine (PC) and TAG, although the PC hydrolysis was stimulated more. In the native lipoproteins, HL showed specificity for PC species containing polyunsaturated fatty acids at sn-2 position, and produced more unsaturated lyso PC species. The enzyme also showed preferential hydrolysis of certain TAG species over others. SM depletion affected the specificity of the enzyme towards PC and TAG species modestly. These results show that SM is a physiological inhibitor of HL activity in lipoproteins and that the specificity of the enzyme towards HDL is at least partly due to its low SM content. Published by Elsevier B.V.

A lack of Wolbachia-specific DNA in samples from apollo butterfly (Parnassius apollo, Lepidoptera: Papilionidae) individuals with deformed or reduced wings.

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Łukasiewicz, Kinga; Sanak, Marek; Węgrzyn, Grzegorz

2016-05-01

Various insects contain maternally inherited endosymbiotic bacteria which can cause reproductive alterations, modulation of some physiological responses (like immunity, heat shock response, and oxidative stress response), and resistance to viral infections. In butterflies, Wolbachia sp. is the most frequent endosymbiont from this group, occurring in about 30 % of species tested to date. In this report, the presence of Wolbachia-specific DNA has been detected in apollo butterfly (Parnassius apollo). In the isolated population of this insect occurring in Pieniny National Park (Poland), malformed individuals with deformed or reduced wings appear with an exceptionally high frequency. Interestingly, while total DNA isolated from most (about 85 %) normal insects contained Wolbachia-specific sequences detected by PCR, such sequences were absent in a large fraction (70 %) of individuals with deformed wings and in all tested individuals with reduced wings. These results indicate for the first time the correlation between malformation of wings and the absence of Wolbachia sp. in insects. Although the lack of the endosymbiotic bacteria cannot be considered as the sole cause of the deformation or reduction of wings, one might suggest that Wolbachia sp. could play a protective role in the ontogenetic development of apollo butterfly.

Brugia malayi gene expression in response to the targeting of the Wolbachia endosymbiont by tetracycline treatment.

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Elodie Ghedin

2009-10-01

Full Text Available Brugia malayi, like most human filarial parasite species, harbors an endosymbiotic bacterium of the genus Wolbachia. Elimination of the endosymbiont leads to sterilization of the adult female. Previous biochemical and genetic studies have established that communication with its endobacterium is essential for survival of the worm.We used electron microscopy to examine the effects of antibiotic treatment on Wolbachia cell structure. We have also used microarray and quantitative RT-PCR analyses to examine the regulation of the B. malayi transcripts altered in response to the anti-Wolbachia treatment. Microscopy of worms taken from animals treated with tetracycline for 14 and 21 days (14 d and 21 d demonstrated substantial morphologic effects on the Wolbachia endobacterium by 14 d and complete degeneration of the endobacterial structures by 21 d. We observed upregulation of transcripts primarily encoding proteins involved in amino acid synthesis and protein translation, and downregulation of transcripts involved in cuticle biosynthesis after both 7 d and 14 d of treatment. In worms exposed to tetracycline in culture, substantial effects on endobacteria morphology were evident by day 3, and extensive death of the endobacteria was observed by day 5. In a detailed examination of the expression kinetics of selected signaling genes carried out on such cultured worms, a bimodal pattern of regulation was observed. The selected genes were upregulated during the early phase of antibiotic treatment and quickly downregulated in the following days. These same genes were upregulated once more at 6 days post-treatment.Upregulation of protein translation and amino acid synthesis may indicate a generalized stress response induced in B. malayi due to a shortage of essential nutrients/factors that are otherwise supplied by Wolbachia. Downregulation of transcripts involved in cuticle biosynthesis perhaps reflects a disruption in the normal embryogenic program. This is

Wolbachia wStri Blocks Zika Virus Growth at Two Independent Stages of Viral Replication.

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Schultz, M J; Tan, A L; Gray, C N; Isern, S; Michael, S F; Frydman, H M; Connor, J H

2018-05-22

Mosquito-transmitted viruses are spread globally and present a great risk to human health. Among the many approaches investigated to limit the diseases caused by these viruses are attempts to make mosquitos resistant to virus infection. Coinfection of mosquitos with the bacterium Wolbachia pipientis from supergroup A is a recent strategy employed to reduce the capacity for major vectors in the Aedes mosquito genus to transmit viruses, including dengue virus (DENV), Chikungunya virus (CHIKV), and Zika virus (ZIKV). Recently, a supergroup B Wolbachia w Stri, isolated from Laodelphax striatellus , was shown to inhibit multiple lineages of ZIKV in Aedes albopictus cells. Here, we show that w Stri blocks the growth of positive-sense RNA viruses DENV, CHIKV, ZIKV, and yellow fever virus by greater than 99.9%. w Stri presence did not affect the growth of the negative-sense RNA viruses LaCrosse virus or vesicular stomatitis virus. Investigation of the stages of the ZIKV life cycle inhibited by w Stri identified two distinct blocks in viral replication. We found a reduction of ZIKV entry into w Stri-infected cells. This was partially rescued by the addition of a cholesterol-lipid supplement. Independent of entry, transfected viral genome was unable to replicate in Wolbachia -infected cells. RNA transfection and metabolic labeling studies suggested that this replication defect is at the level of RNA translation, where we saw a 66% reduction in mosquito protein synthesis in w Stri-infected cells. This study's findings increase the potential for application of w Stri to block additional arboviruses and also identify specific blocks in viral infection caused by Wolbachia coinfection. IMPORTANCE Dengue, Zika, and yellow fever viruses are mosquito-transmitted diseases that have spread throughout the world, causing millions of infections and thousands of deaths each year. Existing programs that seek to contain these diseases through elimination of the mosquito population have so

wMel limits zika and chikungunya virus infection in a Singapore Wolbachia-introgressed Ae. aegypti strain, wMel-Sg.

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Cheong Huat Tan

2017-05-01

Full Text Available Zika (ZIKV and Chikungunya (CHIKV viruses are emerging Aedes-borne viruses that are spreading outside their known geographic range and causing wide-scale epidemics. It has been reported that these viruses can be transmitted efficiently by Ae. aegypti. Recent studies have shown that Ae. aegypti when transinfected with certain Wolbachia strains shows a reduced replication and dissemination of dengue (DENV, Chikungunya (CHIKV, and Yellow Fever (YFV viruses. The aim of this study was to determine whether the wMel strain of Wolbachia introgressed onto a Singapore Ae. aegypti genetic background was able to limit ZIKV and CHIKV infection in the mosquito.Five to seven-day old mosquitoes either infected or uninfected with wMel Wolbachia were orally infected with a Ugandan strain of ZIKV and several outbreak strains of CHIKV. The midgut and salivary glands of each mosquito were sampled at days 6, 9 and 13 days post infectious blood meal to determine midgut infection and salivary glands dissemination rates, respectively. In general, all wild type Ae. aegypti were found to have high ZIKV and CHIKV infections in their midguts and salivary glands, across all sampling days, compared to Wolbachia infected counterparts. Median viral titre for all viruses in Wolbachia infected mosquitoes were significantly lower across all time points when compared to wild type mosquitoes. Most significantly, all but two and one of the wMel infected mosquitoes had no detectable ZIKV and CHIKV, respectively, in their salivary glands at 14 days post-infectious blood meal.Our results showed that wMel limits both ZIKV and CHIKV infection when introgressed into a Singapore Ae. aegypti genetic background. These results also strongly suggest that female Aedes aegypti carrying Wolbachia will have a reduced capacity to transmit ZIKV and CHIKV.

Establishment of a Wolbachia Superinfection in Aedes aegypti Mosquitoes as a Potential Approach for Future Resistance Management.

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D Albert Joubert

2016-02-01

Full Text Available Wolbachia pipientis is an endosymbiotic bacterium estimated to chronically infect between 40-75% of all arthropod species. Aedes aegypti, the principle mosquito vector of dengue virus (DENV, is not a natural host of Wolbachia. The transinfection of Wolbachia strains such as wAlbB, wMel and wMelPop-CLA into Ae. aegypti has been shown to significantly reduce the vector competence of this mosquito for a range of human pathogens in the laboratory. This has led to wMel-transinfected Ae. aegypti currently being released in five countries to evaluate its effectiveness to control dengue disease in human populations. Here we describe the generation of a superinfected Ae. aegypti mosquito line simultaneously infected with two avirulent Wolbachia strains, wMel and wAlbB. The line carries a high overall Wolbachia density and tissue localisation of the individual strains is very similar to each respective single infected parental line. The superinfected line induces unidirectional cytoplasmic incompatibility (CI when crossed to each single infected parental line, suggesting that the superinfection would have the capacity to replace either of the single constituent infections already present in a mosquito population. No significant differences in fitness parameters were observed between the superinfected line and the parental lines under the experimental conditions tested. Finally, the superinfected line blocks DENV replication more efficiently than the single wMel strain when challenged with blood meals from viremic dengue patients. These results suggest that the deployment of superinfections could be used to replace single infections and may represent an effective strategy to help manage potential resistance by DENV to field deployments of single infected strains.

Novel Wolbachia-transinfected Aedes aegypti mosquitoes possess diverse fitness and vector competence phenotypes.

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Johanna E Fraser

2017-12-01

Full Text Available Wolbachia pipientis from Drosophila melanogaster (wMel is an endosymbiotic bacterium that restricts transmission of human pathogenic flaviviruses and alphaviruses, including dengue, Zika, and chikungunya viruses, when introduced into the mosquito vector Aedes aegypti. To date, wMel-infected Ae. aegypti have been released in field trials in 5 countries to evaluate the effectiveness of this strategy for disease control. Despite the success in establishing wMel-infected mosquitoes in wild populations, and the well-characterized antiviral capabilities of wMel, transinfecting different or additional Wolbachia strains into Ae. aegypti may improve disease impact, and perhaps more importantly, could provide a strategy to account for the possible evolution of resistant arboviruses. Here, we report the successful transinfection of Ae. aegypti with the Wolbachia strains wMelCS (D. melanogaster, wRi (D. simulans and wPip (Culex quinquefasciatus and assess the effects on Ae. aegypti fitness, cytoplasmic incompatibility, tissue tropism and pathogen blocking in a laboratory setting. The results demonstrate that wMelCS provides a similar degree of protection against dengue virus as wMel following an infectious blood meal, and significantly reduces viral RNA levels beyond that of wMel following a direct challenge with infectious virus in mosquitoes, with no additional fitness cost to the host. The protection provided by wRi is markedly weaker than that of wMelCS, consistent with previous characterisations of these lines in Drosophila, while wPip was found to substantially reduce the fitness of Ae. aegypti. Thus, we determine wMelCS as a key candidate for further testing in field-relevant fitness tests and viremic blood feeding challenges in a clinical setting to determine if it may represent an alternative Wolbachia strain with more desirable attributes than wMel for future field testing.

Novel Wolbachia-transinfected Aedes aegypti mosquitoes possess diverse fitness and vector competence phenotypes.

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Fraser, Johanna E; De Bruyne, Jyotika Taneja; Iturbe-Ormaetxe, Iñaki; Stepnell, Justin; Burns, Rhiannon L; Flores, Heather A; O'Neill, Scott L

2017-12-01

Wolbachia pipientis from Drosophila melanogaster (wMel) is an endosymbiotic bacterium that restricts transmission of human pathogenic flaviviruses and alphaviruses, including dengue, Zika, and chikungunya viruses, when introduced into the mosquito vector Aedes aegypti. To date, wMel-infected Ae. aegypti have been released in field trials in 5 countries to evaluate the effectiveness of this strategy for disease control. Despite the success in establishing wMel-infected mosquitoes in wild populations, and the well-characterized antiviral capabilities of wMel, transinfecting different or additional Wolbachia strains into Ae. aegypti may improve disease impact, and perhaps more importantly, could provide a strategy to account for the possible evolution of resistant arboviruses. Here, we report the successful transinfection of Ae. aegypti with the Wolbachia strains wMelCS (D. melanogaster), wRi (D. simulans) and wPip (Culex quinquefasciatus) and assess the effects on Ae. aegypti fitness, cytoplasmic incompatibility, tissue tropism and pathogen blocking in a laboratory setting. The results demonstrate that wMelCS provides a similar degree of protection against dengue virus as wMel following an infectious blood meal, and significantly reduces viral RNA levels beyond that of wMel following a direct challenge with infectious virus in mosquitoes, with no additional fitness cost to the host. The protection provided by wRi is markedly weaker than that of wMelCS, consistent with previous characterisations of these lines in Drosophila, while wPip was found to substantially reduce the fitness of Ae. aegypti. Thus, we determine wMelCS as a key candidate for further testing in field-relevant fitness tests and viremic blood feeding challenges in a clinical setting to determine if it may represent an alternative Wolbachia strain with more desirable attributes than wMel for future field testing.

Wolbachia infection in Aedes aegypti mosquitoes alters blood meal excretion and delays oviposition without affecting trypsin activity.

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Pimenta de Oliveira, Sofia; Dantas de Oliveira, Caroline; Viana Sant'Anna, Mauricio Roberto; Carneiro Dutra, Heverton Leandro; Caragata, Eric Pearce; Moreira, Luciano Andrade

2017-08-01

Blood feeding in Aedes aegypti is essential for reproduction, but also permits the mosquito to act as a vector for key human pathogens such as the Zika and dengue viruses. Wolbachia pipientis is an endosymbiotic bacterium that can manipulate the biology of Aedes aegypti mosquitoes, making them less competent hosts for many pathogens. Yet while Wolbachia affects other aspects of host physiology, it is unclear whether it influences physiological processes associated with blood meal digestion. To that end, we examined the effects of wMel Wolbachia infection in Ae. aegypti, on survival post-blood feeding, blood meal excretion, rate of oviposition, expression levels of key genes involved in oogenesis, and activity levels of trypsin blood digestion enzymes. We observed that wMel infection altered the rate and duration of blood meal excretion, delayed the onset of oviposition and was associated with a greater number of eggs being laid later. wMel-infected Ae. aegypti also had lower levels of key yolk protein precursor genes necessary for oogenesis. However, all of these effects occurred without a change in trypsin activity. These results suggest that Wolbachia infection may disrupt normal metabolic processes associated with blood feeding and reproduction in Ae. aegypti. Copyright © 2017 Elsevier Ltd. All rights reserved.

Staphylococcus aureus lipoproteins trigger human corneal epithelial innate response through toll-like receptor-2

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Li, Qiong; Kumar, Ashok; Gui, Jian-Fang; Yu, Fu-Shin X.

2007-01-01

Bacterial lipoproteins (LP) are a family of cell wall components found in a wide variety of bacteria. In this study, we characterized the response of HUCL, a telomerase-immortalized human corneal epithelial cell (HCEC) line, to LP isolated from Staphylococcus (S) aureus. S. aureus LP (saLP) prepared by Triton X-114 extraction stimulated the activation of NF-κB, JNK, and P38 signaling pathways in HUCL cells. The extracts failed to stimulate NF-κB activation in HUCL cells after lipoprotein lipa...

Wolbachia wSinvictaA infections in natural populations of the fire ant Solenopsis invicta: testing for phenotypic effects.

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Bouwma, Andrew M; Shoemaker, Dewayne

2011-01-01

Wolbachia are intracellular bacteria that commonly infect many arthropods and some nematodes. In arthropods, these maternally transmitted bacteria often induce a variety of phenotypic effects to enhance their own spread within host populations. Wolbachia phenotypic effects generally either provide benefits to infected host females (cytoplasmic incompatibility, positive fitness effects) or bias host sex ratio in favor of females (male-killing, parthenogenesis, feminization), all of which increase the relative production of infected females in host populations. Wolbachia surveys have found infections to be exceedingly common in ants, but little is known at this juncture as to what phenotypic effects, if any, they induce in this group. Previous studies have demonstrated that individuals from native populations of the invasive fire ant Solenopsis invicta commonly harbor one or more of three Wolbachia variants. One of the variants, wSinvictaA, typically occurs at low prevalence in S. invicta populations, appears to have been transmitted horizontally into S. invicta three or more times, and has been lost repeatedly from host lineages over time. In order to determine the phenotypic effects and likely population dynamics of wSinvictaA infections in these ants, brood production patterns of newly mated fire ant queens were studied during simulated claustral founding and measured wSinvictaA transmission fidelity within mature single-queen families. No clear evidence was found for Wolbachia-induced cytoplasmic incompatibility, significant fitness effects, or male-killing. Maternal transmission was perfect to both virgin queens and males. Possible mechanisms for how this variant could be maintained in host populations are discussed.

Activation of Murine Macrophages by Lipoprotein and Lipooligosaccharide of Treponema denticola

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Rosen, Graciela; Sela, Michael N.; Naor, Ronit; Halabi, Amal; Barak, Vivian; Shapira, Lior

1999-01-01

We have recently demonstrated that the periodontopathogenic oral spirochete Treponema denticola possesses membrane-associated lipoproteins in addition to lipooligosaccharide (LOS). The aim of the present study was to test the potential of these oral spirochetal components to induce the production of inflammatory mediators by human macrophages, which in turn may stimulate tissue breakdown as observed in periodontal diseases. An enriched lipoprotein fraction (dLPP) from T. denticola ATCC 35404 ...

Native High Density Lipoproteins (HDL Interfere with Platelet Activation Induced by Oxidized Low Density Lipoproteins (OxLDL

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Ivo Volf

2013-05-01

Full Text Available Platelets and lipoproteins play a crucial role in atherogenesis, in part by their ability to modulate inflammation and oxidative stress. While oxidized low density lipoproteins (OxLDL play a central role in the development of this disease, high density lipoproteins (HDL represent an atheroprotective factor of utmost importance. As platelet function is remarkably sensitive to the influence of plasma lipoproteins, it was the aim of this study to clarify if HDL are able to counteract the stimulating effects of OxLDL with special emphasis on aspects of platelet function that are relevant to inflammation. Therefore, HDL were tested for their ability to interfere with pro-thrombotic and pro-inflammatory aspects of platelet function. We are able to show that HDL significantly impaired OxLDL-induced platelet aggregation and adhesion. In gel-filtered platelets, HDL decreased both the formation of reactive oxygen species and CD40L expression. Furthermore, HDL strongly interfered with OxLDL-induced formation of platelet-neutrophil aggregates in whole blood, suggesting that platelets represent a relevant and sensitive target for HDL. The finding that HDL effectively competed with the binding of OxLDL to the platelet surface might contribute to their atheroprotective and antithrombotic properties.

Activation of lipoprotein lipase by lipoprotein fractions of human serum.

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Bier, D M; Havel, R J

1970-11-01

Triglycerides in fat emulsions are hydrolyzed by lipoprotein lipase only when they are "activated" by serum lipoproteins. The contribution of different lipoprotein fractions to hydrolysis of triglycerides in soybean oil emulsion was assessed by determining the quantity of lipoprotein fraction required to give half-maximal hydrolysis. Most of the activator property of whole serum from normolipidemic, postabsorptive subjects was in high density lipoproteins. Low density lipoproteins and serum from which all lipoprotein classes were removed had little or no activity. Also, little activator was present in guinea pig serum or in very low density poor serum from an individual with lecithin:cholesterol acyltransferase deficiency, both of which are deficient in high density lipoproteins. Human very low density lipoproteins are potent activators and are much more active than predicted from their content of high density lipoprotein-protein. Per unit weight of protein, very low density lipoproteins had 13 times the activity of high density lipoproteins. These observations suggest that one or more of the major apoproteins of very low density lipoproteins, present as a minor constituent of high density lipoproteins, may be required for the activation process.

The joint evolutionary histories of Wolbachia and mitochondria in Hypolimnas bolina

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Roderick George K

2009-03-01

Full Text Available Abstract Background The interaction between the Blue Moon butterfly, Hypolimnas bolina, and Wolbachia has attracted interest because of the high prevalence of male-killing achieved within the species, the ecological consequences of this high prevalence, the intensity of selection on the host to suppress the infection, and the presence of multiple Wolbachia infections inducing different phenotypes. We examined diversity in the co-inherited marker, mtDNA, and the partitioning of this between individuals of different infection status, as a means to investigate the population biology and evolutionary history of the Wolbachia infections. Results Part of the mitochondrial COI gene was sequenced from 298 individuals of known infection status revealing ten different haplotypes. Despite very strong biological evidence that the sample represents a single species, the ten haplotypes did not fall within a monophyletic clade within the Hypolimnas genus, with one haplotype differing by 5% from the other nine. There were strong associations between infection status and mtDNA haplotype. The presence of wBol1 infection in association with strongly divergent haplotypes prompted closer examination of wBol1 genetic variation. This revealed the existence of two cryptic subtypes, wBol1a and wBol1b. The wBol1a infection, by far the most common, was in strict association with the single divergent mtDNA haplotype. The wBol1b infection was found with two haplotypes that were also observed in uninfected specimens. Finally, the wBol2 infection was associated with a large diversity of mtDNA haplotypes, most often shared with uninfected sympatric butterflies. Conclusion This data overall supports the hypothesis that high prevalence of male-killing Wolbachia (wBol1 in H. bolina is associated with very high transmission efficiency rather than regular horizontal transmission. It also suggests this infection has undergone a recent selective sweep and was introduced in this

Understanding Wolbachia acquisition and co-divergence of hosts and their associated bacteria: Wolbachia infection in the Chorthippus parallelus hybrid zone

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Paloma, Martinez-Rodriguez; Luis, Bella; Francisca, Arroyo-Yebras

2016-01-01

Wolbachia is one of the best known bacterial endosymbionts affecting insects and nematodes. It is estimated that it infects 40% of insect species, so epidemiologically it may be considered a pandemic species. However, the mechanisms by which it is acquired from other species (horizontal transmission) or by which it coevolves with its hosts as a result of vertical transmission across generations are not known in detail. In fact, there are few systems in which the codivergence between host and ...

Plasma Lipoprotein-associated Phospholipase A(2) Is Inversely Correlated with Proprotein Convertase Subtilisin-kexin Type 9

NARCIS (Netherlands)

Constantinides, Alexander; Kappelle, Paul J.W.H.; Lambert, Gilles; Dullaart, Robin P. F.

Background and Aims. Lipoprotein-associated phospholipase A(2) (Lp-PLA(2)) is a proatherogenic phospholipase A(2), which is predominantly complexed to low-density lipoprotein (LDL) particles. Proprotein convertase subtilisin-kexin type 9 (PCSK9) provides a key step in LDL metabolism by stimulating

Detection of Wolbachia pipientis, including a new strain containing the wsp gene, in two sister species of Paraphlebotomus sandflies, potential vectors of zoonotic cutaneous leishmaniasis

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Parviz Parvizi

2013-06-01

Full Text Available Individual, naturally occurring Phlebotomus mongolensis and Phlebotomus caucasicus from Iran were screened for infections with the maternally inherited intracellular Rickettsia-like bacterium Wolbachia pipientis via targeting a major surface protein gene (wsp. The main objective of this study was to determine if W. pipientis could be detected in these species. The sandflies were screened using polymerase chain reaction to amplify a fragment of the Wolbachia surface protein gene. The obtained sequences were edited and aligned with database sequences to identify W. pipientis haplotypes. Two strains of Wolbachia were found. Strain Turk 54 (accession EU780683 is widespread and has previously been reported in Phlebotomus papatasi and other insects. Strain Turk 07 (accession KC576916 is a novel strain, found for first time in the two sister species. A-group strains of W. pipientis occur throughout much of the habitat of these sandflies. It is possible that Wolbachia is transferred via horizontal transmission. Horizontal transfer could shed light on sandfly control because Wolbachia is believed to drive a deleterious gene into sandflies that reduces their natural population density. With regard to our findings in this study, we can conclude that one species of sandfly can be infected with different Wolbachia strains and that different species of sandflies can be infected with a common strain.

Cholesteryl ester transfer activity in plasma measured by using solid-phase-bound high-density lipoprotein

International Nuclear Information System (INIS)

Sparks, D.L.; Frohlich, J.; Cullis, P.; Pritchard, P.H.

1987-01-01

We studied the ability of lipid-transfer factors in plasma to promote transfer, to endogenous lipoproteins, of [ 3 H]cholesteryl ester from high-density lipoprotein (HDL) covalently bound to Sepharose 4B beads. After incubation for 2 h at 37 degrees C, 12 to 14% of the [ 3 H]cholesteryl ester had been transferred to the lipoproteins of the plasma, in the proportions 57% to HDL and 43% to low- and very-low-density lipoproteins. This process was a function of the amount of plasma present and was stimulated by addition of partly purified lipid-transfer protein. Transfer also depended on the concentration of donor HDL but was independent of the amount of acceptor lipoprotein. This simple evaluation of cholesteryl ester transfer does not require removal of lipoproteins from the plasma before incubation

Epidemiology of asexuality induced by the endosymbiotic Wolbachia across phytophagous wasp species: host plant specialization matters.

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Boivin, T; Henri, H; Vavre, F; Gidoin, C; Veber, P; Candau, J-N; Magnoux, E; Roques, A; Auger-Rozenberg, M-A

2014-05-01

Among eukaryotes, sexual reproduction is by far the most predominant mode of reproduction. However, some systems maintaining sexuality appear particularly labile and raise intriguing questions on the evolutionary routes to asexuality. Thelytokous parthenogenesis is a form of spontaneous loss of sexuality leading to strong distortion of sex ratio towards females and resulting from mutation, hybridization or infection by bacterial endosymbionts. We investigated whether ecological specialization is a likely mechanism of spread of thelytoky within insect communities. Focusing on the highly specialized genus Megastigmus (Hymenoptera: Torymidae), we first performed a large literature survey to examine the distribution of thelytoky in these wasps across their respective obligate host plant families. Second, we tested for thelytoky caused by endosymbionts by screening in 15 arrhenotokous and 10 thelytokous species for Wolbachia, Cardinium, Arsenophonus and Rickettsia endosymbionts and by performing antibiotic treatments. Finally, we performed phylogenetic reconstructions using multilocus sequence typing (MLST) to examine the evolution of endosymbiont-mediated thelytoky in Megastigmus and its possible connections to host plant specialization. We demonstrate that thelytoky evolved from ancestral arrhenotoky through the horizontal transmission and the fixation of the parthenogenesis-inducing Wolbachia. We find that ecological specialization in Wolbachia's hosts was probably a critical driving force for Wolbachia infection and spread of thelytoky, but also a constraint. Our work further reinforces the hypothesis that community structure of insects is a major driver of the epidemiology of endosymbionts and that competitive interactions among closely related species may facilitate their horizontal transmission. © 2014 John Wiley & Sons Ltd.

Streptococcus gordonii lipoproteins induce IL-8 in human periodontal ligament cells.

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Kim, A Reum; Ahn, Ki Bum; Kim, Hyun Young; Seo, Ho Seong; Kum, Kee-Yeon; Yun, Cheol-Heui; Han, Seung Hyun

2017-11-01

Streptococcus gordonii, a Gram-positive oral bacterium, is a life-threatening pathogen that causes infective endocarditis. It is frequently isolated from the periapical lesions of patients with apical periodontitis and has thus been implicated in inflammatory responses. However, little is known about the virulence factors of S. gordonii responsible for the induction of inflammatory responses in the periapical areas. Here, we investigated the role of S. gordonii cell wall-associated virulence factors on interleukin (IL)-8 induction in human periodontal ligament (PDL) cells using ethanol-inactivated wild-type S. gordonii, a lipoteichoic acid (LTA)-deficient mutant (ΔltaS), and a lipoprotein-deficient mutant (Δlgt). Wild-type S. gordonii induced IL-8 expression at both the protein and mRNA levels in human PDL cells in a dose- and time-dependent manner. A transient transfection and reporter gene assay demonstrated that wild-type S. gordonii activated Toll-like receptor 2 (TLR2). Additionally, IL-8 production induced by wild-type S. gordonii was substantially inhibited by anti-TLR2-neutralizing antibodies. Both wild-type S. gordonii and the ΔltaS mutant induced IL-8 production; however, this response was not observed when cells were stimulated with the Δlgt mutant. Interestingly, lipoproteins purified from S. gordonii induced IL-8 production, whereas purified LTA did not. In addition, purified lipoproteins stimulated TLR2 more potently than LTA. Furthermore, S. gordonii-induced IL-8 expression was specifically inhibited by blocking p38 kinase, while lipoprotein-induced IL-8 expression was inhibited by blocking p38 kinase, ERK, or JNK. Of particular note, exogenous addition of purified S. gordonii lipoproteins enhanced Δlgt-induced IL-8 production in human PDL cells to an extent similar to that induced by the wild-type strain. Collectively, these results suggest that lipoproteins are an important component of S. gordonii for the induction of IL-8 production in human

TLR2-Modulating Lipoproteins of the Mycobacterium tuberculosis Complex Enhance the HIV Infectivity of CD4+ T Cells.

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Ciaran Skerry

Full Text Available Co-infection with Mycobacterium tuberculosis accelerates progression from HIV to AIDS. Our previous studies showed that M. tuberculosis complex, unlike M. smegmatis, enhances TLR2-dependent susceptibility of CD4+ T cells to HIV. The M. tuberculosis complex produces multiple TLR2-stimulating lipoproteins, which are absent in M. smegmatis. M. tuberculosis production of mature lipoproteins and TLR2 stimulation is dependent on cleavage by lipoprotein signal peptidase A (LspA. In order to determine the role of potential TLR2-stimulating lipoproteins on mycobacterial-mediated HIV infectivity of CD4+ T cells, we generated M. smegmatis recombinant strains overexpressing genes encoding various M. bovis BCG lipoproteins, as well as a Mycobacterium bovis BCG strain deficient in LspA (ΔlspA. Exposure of human peripheral blood mononuclear cells (PBMC to M. smegmatis strains overexpressing the BCG lipoproteins, LprF (p<0.01, LprH (p<0.05, LprI (p<0.05, LprP (p<0.001, LprQ (p<0.005, MPT83 (p<0.005, or PhoS1 (p<0.05, resulted in increased HIV infectivity of CD4+ T cells isolated from these PBMC. Conversely, infection of PBMC with ΔlspA reduced HIV infectivity of CD4+ T cells by 40% relative to BCG-infected cells (p<0.05. These results may have important implications for TB vaccination programs in areas with high mother-to-child HIV transmission.

TLR2-Modulating Lipoproteins of the Mycobacterium tuberculosis Complex Enhance the HIV Infectivity of CD4+ T Cells.

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Skerry, Ciaran; Klinkenberg, Lee G; Page, Kathleen R; Karakousis, Petros C

2016-01-01

Co-infection with Mycobacterium tuberculosis accelerates progression from HIV to AIDS. Our previous studies showed that M. tuberculosis complex, unlike M. smegmatis, enhances TLR2-dependent susceptibility of CD4+ T cells to HIV. The M. tuberculosis complex produces multiple TLR2-stimulating lipoproteins, which are absent in M. smegmatis. M. tuberculosis production of mature lipoproteins and TLR2 stimulation is dependent on cleavage by lipoprotein signal peptidase A (LspA). In order to determine the role of potential TLR2-stimulating lipoproteins on mycobacterial-mediated HIV infectivity of CD4+ T cells, we generated M. smegmatis recombinant strains overexpressing genes encoding various M. bovis BCG lipoproteins, as well as a Mycobacterium bovis BCG strain deficient in LspA (ΔlspA). Exposure of human peripheral blood mononuclear cells (PBMC) to M. smegmatis strains overexpressing the BCG lipoproteins, LprF (p<0.01), LprH (p<0.05), LprI (p<0.05), LprP (p<0.001), LprQ (p<0.005), MPT83 (p<0.005), or PhoS1 (p<0.05), resulted in increased HIV infectivity of CD4+ T cells isolated from these PBMC. Conversely, infection of PBMC with ΔlspA reduced HIV infectivity of CD4+ T cells by 40% relative to BCG-infected cells (p<0.05). These results may have important implications for TB vaccination programs in areas with high mother-to-child HIV transmission.

Lipoproteins and lipoprotein mimetics for imaging and drug delivery.

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Thaxton, C Shad; Rink, Jonathan S; Naha, Pratap C; Cormode, David P

2016-11-15

Lipoproteins are a set of natural nanoparticles whose main role is the transport of fats within the body. While much work has been done to develop synthetic nanocarriers to deliver drugs or contrast media, natural nanoparticles such as lipoproteins represent appealing alternatives. Lipoproteins are biocompatible, biodegradable, non-immunogenic and are naturally targeted to some disease sites. Lipoproteins can be modified to act as contrast agents in many ways, such as by insertion of gold cores to provide contrast for computed tomography. They can be loaded with drugs, nucleic acids, photosensitizers or boron to act as therapeutics. Attachment of ligands can re-route lipoproteins to new targets. These attributes render lipoproteins attractive and versatile delivery vehicles. In this review we will provide background on lipoproteins, then survey their roles as contrast agents, in drug and nucleic acid delivery, as well as in photodynamic therapy and boron neutron capture therapy. Copyright © 2016 Elsevier B.V. All rights reserved.

Sort1, encoded by the cardiovascular risk locus 1p13.3, is a regulator of hepatic lipoprotein export

DEFF Research Database (Denmark)

Kjølby, Mads Fuglsang; Andersen, Olav Michael; Breiderhoff, Tilman

2010-01-01

of lipoproteins from the liver and ameliorates hypercholesterolemia and atherosclerotic lesion formation in LDL receptor-deficient animals. In contrast, sortilin overexpression stimulates hepatic release of lipoproteins and increases plasma LDL levels. Our data have uncovered a regulatory pathway in hepatic...... lipoprotein export and suggest a molecular explanation for the cardiovascular risk being associated with 1p13.3. Udgivelsesdato: september 8...

Wolbachia Effects on Rift Valley Virus Infection in Culex tarsalis Mosquitoes

Science.gov (United States)

2017-04-25

Wolbachia density in mosquitoes. 109" 110" Materials and Methods 111" Ethics statement 112" TR-17-113 Mosquitoes were maintained on commercially available...fever virus. 379" Vet Med Today. 2009; 883–893. 380" 29. Wilson M. Rift Valley fever virus ecology and the epidemiology of disease emergence. 381

Lipoprotein(a)

DEFF Research Database (Denmark)

Langsted, Anne; Kamstrup, Pia R; Nordestgaard, Børge G

2014-01-01

OBJECTIVE: There are no recommendations in guidelines on measuring lipoprotein(a) in the fasting or nonfasting state, or on the influence of inflammation. We tested the hypotheses that lipoprotein(a) levels change only minimally in response to normal food intake, and to inflammation. Also, we...... tested whether normal food intake or inflammation influenced lipoprotein(a)'s ability to predict ischemic heart disease. METHODS: We studied 34 829 individuals from the Danish general population using the Copenhagen General Population Study and the Copenhagen City Heart Study. RESULTS: Lipoprotein......(a) levels did not change in response to normal food intake: median fasting levels were 17.3 mg/dL, while median levels at 3-4 h since last meal were 19.4 mg/dL(p = 0.38). Lipoprotein(a) levels increased minimally with increasing levels of C-reactive protein(CRP): median lipoprotein(a) levels at CRP

Repurposing of approved drugs from the human pharmacopoeia to target Wolbachia endosymbionts of onchocerciasis and lymphatic filariasis

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Kelly L. Johnston

2014-12-01

Full Text Available Lymphatic filariasis and onchocerciasis are debilitating diseases caused by parasitic filarial nematodes infecting around 150 million people throughout the tropics with more than 1.5 billion at risk. As with other neglected tropical diseases, classical drug-discovery and development is lacking and a 50 year programme of macrofilaricidal discovery failed to deliver a drug which can be used as a public health tool. Recently, antibiotic targeting of filarial Wolbachia, an essential bacterial symbiont, has provided a novel drug treatment for filariasis with macrofilaricidal activity, although the current gold-standard, doxycycline, is unsuitable for use in mass drug administration (MDA. The anti-Wolbachia (A·WOL Consortium aims to identify novel anti-Wolbachia drugs, compounds or combinations that are suitable for use in MDA. Development of a Wolbachia cell-based assay has enabled the screening of the approved human drug-pharmacopoeia (∼2600 drugs for a potential repurposing. This screening strategy has revealed that approved drugs from various classes show significant bacterial load reduction equal to or superior to the gold-standard doxycycline, with 69 orally available hits from different drug categories being identified. Based on our defined hit criteria, 15 compounds were then selectively screened in a Litomosoides sigmodontis mouse model, 4 of which were active. These came from the tetracycline, fluoroquinolone and rifamycin classes. This strategy of repurposing approved drugs is a promising development in the goal of finding a novel treatment against filariasis and could also be a strategy applicable for other neglected tropical diseases.

Activation of murine macrophages by lipoprotein and lipooligosaccharide of Treponema denticola.

Science.gov (United States)

Rosen, G; Sela, M N; Naor, R; Halabi, A; Barak, V; Shapira, L

1999-03-01

We have recently demonstrated that the periodontopathogenic oral spirochete Treponema denticola possesses membrane-associated lipoproteins in addition to lipooligosaccharide (LOS). The aim of the present study was to test the potential of these oral spirochetal components to induce the production of inflammatory mediators by human macrophages, which in turn may stimulate tissue breakdown as observed in periodontal diseases. An enriched lipoprotein fraction (dLPP) from T. denticola ATCC 35404 obtained upon extraction of the treponemes with Triton X-114 was found to stimulate the production of nitric oxide (NO), tumor necrosis factor alpha (TNF-alpha), and interleukin-1 (IL-1) by mouse macrophages in a dose-dependent manner. Induction of NO by dLPP was at 25% of the levels obtained by Salmonella typhosa lipopolysaccharide (LPS) at similar concentrations, while IL-1 was produced at similar levels by both inducers. dLPP-mediated macrophage activation was unaffected by amounts of polymyxin B that neutralized the induction produced by S. typhosa LPS. dLPP also induced NO and TNF-alpha secretion from macrophages isolated from endotoxin-unresponsive C3H/HeJ mice to an extent similar to the stimulation produced in endotoxin-responsive mice. Purified T. denticola LOS also produced a concentration-dependent activation of NO and TNF-alpha in LPS-responsive and -nonresponsive mouse macrophages. However, macrophage activation by LOS was inhibited by polymyxin B. These results suggest that T. denticola lipoproteins and LOS may play a role in the inflammatory processes that characterize periodontal diseases.

Phylogeography of Nasonia vitripennis (Hymenoptera) indicates a mitochondrial-Wolbachia sweep in North America

NARCIS (Netherlands)

Raychoudhury, R.; Grillenberger, B. K.; Gadau, J.; Bijlsma, R.; van de Zande, L.; Werren, J. H.; Beukeboom, L. W.

Here we report evidence of a mitochondrial-Wolbachia sweep in North American populations of the parasitoid wasp Nasonia vitripennis, a cosmopolitan species and emerging model organism for evolutionary and genetic studies. Analysis of the genetic variation of 89 N. vitripennis specimens from Europe

Remnant lipoproteins

DEFF Research Database (Denmark)

Varbo, Anette; Nordestgaard, Børge G.

2017-01-01

Purpose of review: To review recent advances in the field of remnant lipoproteins and remnant cholesterol with a focus on cardiovascular disease risk. Recent findings: In line with previous years' research, current observational, genetic, and mechanistic studies find remnant lipoproteins (defined...... of cardiovascular disease risk reduction through remnant lipoprotein lowering are under way....

Involvement of microtubules in lipoprotein degradation and utilization for steroidogenesis in cultured rat luteal cells

International Nuclear Information System (INIS)

Rajan, V.P.; Menon, K.M.

1985-01-01

Cells isolated from superovulated rat ovaries metabolize low density lipoprotein (LDL) and high density lipoprotein (HDL) of human or rat origin and use the lipoprotein-derived cholesterol as a precursor for progesterone production. Under in vitro conditions, both lipoproteins are internalized and degraded in the lysosomes, although degradation of HDL is of lower magnitude than that of LDL. In this report we have examined the role of cellular microtubules in the internalization and degradation of human LDL and HDL in cultured rat luteal cells. The microtubule depolymerizing agents colchicine, podophyllotoxin, vinblastine, and nocodazole as well as taxol, deuterium oxide, and dimethyl sulfoxide, which are known to rapidly polymerize cellular tubulin into microtubules, were used to block the function of microtubules. When these antimicrotubule agents were included in the incubations, degradation of the apolipoproteins of [ 125 I]iodo-LDL and [ 125 I]iodo-HDL by the luteal cells was inhibited by 50-85% compared to untreated control values. Maximum inhibitory effects were observed when the cells were preincubated with the inhibitor for at least 4 h at 37 C before treatment with the labeled lipoprotein. Lipoprotein-stimulated progesterone production by luteal cells was also inhibited by 50% or more in the presence of antimicrotubule agents. However, basal and hCG-stimulated progesterone production were unaffected by these inhibitors. The binding of [ 125 I]iodo-LDL and [ 125 I]iodo-HDL to luteal cell plasma membrane receptors was not affected by the microtubule inhibitors. Although binding was unaffected and degradation was impaired in the presence of the inhibitors, there was no detectable accumulation of undegraded lipoprotein within the cells during the 24 h of study

Native low-density lipoprotein uptake by macrophage colony-stimulating factor-differentiated human macrophages is mediated by macropinocytosis and micropinocytosis.

Science.gov (United States)

Anzinger, Joshua J; Chang, Janet; Xu, Qing; Buono, Chiara; Li, Yifu; Leyva, Francisco J; Park, Bum-Chan; Greene, Lois E; Kruth, Howard S

2010-10-01

To examine the pinocytotic pathways mediating native low-density lipoprotein (LDL) uptake by human macrophage colony-stimulating factor-differentiated macrophages (the predominant macrophage phenotype in human atherosclerotic plaques). We identified the kinase inhibitor SU6656 and the Rho GTPase inhibitor toxin B as inhibitors of macrophage fluid-phase pinocytosis of LDL. Assessment of macropinocytosis by time-lapse microscopy revealed that both drugs almost completely inhibited macropinocytosis, although LDL uptake and cholesterol accumulation by macrophages were only partially inhibited (approximately 40%) by these agents. Therefore, we investigated the role of micropinocytosis in mediating LDL uptake in macrophages and identified bafilomycin A1 as an additional partial inhibitor (approximately 40%) of macrophage LDL uptake that targeted micropinocytosis. When macrophages were incubated with both bafilomycin A1 and SU6656, inhibition of LDL uptake was additive (reaching 80%), showing that these inhibitors target different pathways. Microscopic analysis of fluid-phase uptake pathways in these macrophages confirmed that LDL uptake occurs through both macropinocytosis and micropinocytosis. Our findings show that human macrophage colony-stimulating factor-differentiated macrophages take up native LDL by macropinocytosis and micropinocytosis, underscoring the importance of both pathways in mediating LDL uptake by these cells.

wFlu: characterization and evaluation of a native Wolbachia from the mosquito Aedes fluviatilis as a potential vector control agent.

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Luke Anthony Baton

Full Text Available There is currently considerable interest and practical progress in using the endosymbiotic bacteria Wolbachia as a vector control agent for human vector-borne diseases. Such vector control strategies may require the introduction of multiple, different Wolbachia strains into target vector populations, necessitating the identification and characterization of appropriate endosymbiont variants. Here, we report preliminary characterization of wFlu, a native Wolbachia from the neotropical mosquito Aedes fluviatilis, and evaluate its potential as a vector control agent by confirming its ability to cause cytoplasmic incompatibility, and measuring its effect on three parameters determining host fitness (survival, fecundity and fertility, as well as vector competence (susceptibility for pathogen infection. Using an aposymbiotic strain of Ae. fluviatilis cured of its native Wolbachia by antibiotic treatment, we show that in its natural host wFlu causes incomplete, but high levels of, unidirectional cytoplasmic incompatibility, has high rates of maternal transmission, and no detectable fitness costs, indicating a high capacity to rapidly spread through host populations. However, wFlu does not inhibit, and even enhances, oocyst infection with the avian malaria parasite Plasmodium gallinaceum. The stage- and sex-specific density of wFlu was relatively low, and with limited tissue distribution, consistent with the lack of virulence and pathogen interference/symbiont-mediated protection observed. Unexpectedly, the density of wFlu was also shown to be specifically-reduced in the ovaries after bloodfeeding Ae. fluviatilis. Overall, our observations indicate that the Wolbachia strain wFlu has the potential to be used as a vector control agent, and suggests that appreciable mutualistic coevolution has occurred between this endosymbiont and its natural host. Future work will be needed to determine whether wFlu has virulent host effects and/or exhibits pathogen

Activation of Murine Macrophages by Lipoprotein and Lipooligosaccharide of Treponema denticola

Science.gov (United States)

Rosen, Graciela; Sela, Michael N.; Naor, Ronit; Halabi, Amal; Barak, Vivian; Shapira, Lior

1999-01-01

We have recently demonstrated that the periodontopathogenic oral spirochete Treponema denticola possesses membrane-associated lipoproteins in addition to lipooligosaccharide (LOS). The aim of the present study was to test the potential of these oral spirochetal components to induce the production of inflammatory mediators by human macrophages, which in turn may stimulate tissue breakdown as observed in periodontal diseases. An enriched lipoprotein fraction (dLPP) from T. denticola ATCC 35404 obtained upon extraction of the treponemes with Triton X-114 was found to stimulate the production of nitric oxide (NO), tumor necrosis factor alpha (TNF-α), and interleukin-1 (IL-1) by mouse macrophages in a dose-dependent manner. Induction of NO by dLPP was at 25% of the levels obtained by Salmonella typhosa lipopolysaccharide (LPS) at similar concentrations, while IL-1 was produced at similar levels by both inducers. dLPP-mediated macrophage activation was unaffected by amounts of polymyxin B that neutralized the induction produced by S. typhosa LPS. dLPP also induced NO and TNF-α secretion from macrophages isolated from endotoxin-unresponsive C3H/HeJ mice to an extent similar to the stimulation produced in endotoxin-responsive mice. Purified T. denticola LOS also produced a concentration-dependent activation of NO and TNF-α in LPS-responsive and -nonresponsive mouse macrophages. However, macrophage activation by LOS was inhibited by polymyxin B. These results suggest that T. denticola lipoproteins and LOS may play a role in the inflammatory processes that characterize periodontal diseases. PMID:10024558

Lipoprotein complex formation

International Nuclear Information System (INIS)

Musliner, T.A.; Krauss, R.M.

1987-01-01

Transfers of lipids and proteins between different lipoproteins are known to occur in the course of their metabolism. It is likely that these transfers take place during transient physical associations between lipoprotein particles, but the nature and chemical basis for such interactions are poorly understood. The fact that lipid and apolipoprotein movements are particularly prevalent during the intravascular lipolysis of triglyceride-rich lipoproteins suggested to us that lipolysis products accumulating on these particles might promote physical binding with other lipoproteins. To test this hypothesis, we studied interactions between very low-density, low density, and high-density lipoproteins in the setting of partial lipolysis by bovine milk lipoprotein lipase in the presence of limited unesterified fatty acid acceptor. 2 figs., 1 tab

Variation in Wolbachia effects on Aedes mosquitoes as a determinant of invasiveness and vectorial capacity.

Science.gov (United States)

King, Jessica G; Souto-Maior, Caetano; Sartori, Larissa M; Maciel-de-Freitas, Rafael; Gomes, M Gabriela M

2018-04-16

Wolbachia has been introduced into Aedes aegypti mosquitoes to control the spread of arboviruses, such as dengue, chikungunya and Zika. Studies showed that certain Wolbachia strains (such as wMel) reduce replication of dengue viruses in the laboratory, prompting the release of mosquitoes carrying the bacterium into the field, where vectorial capacity can be realistically assessed in relation to native non-carriers. Here we apply a new analysis to two published datasets, and show that wMel increases the mean and the variance in Ae. aegypti susceptibility to dengue infection when introgressed into Brazil and Vietnam genetic backgrounds. In the absence of other processes, higher mean susceptibility should lead to enhanced viral transmission. The increase in variance, however, widens the basis for selection imposed by unexplored natural forces, retaining the potential for reducing transmission overall.

Identification and Localization of Myxococcus xanthus Porins and Lipoproteins

Science.gov (United States)

Bhat, Swapna; Zhu, Xiang; Patel, Ricky P.; Orlando, Ron; Shimkets, Lawrence J.

2011-01-01

Myxococcus xanthus DK1622 contains inner (IM) and outer membranes (OM) separated by a peptidoglycan layer. Integral membrane, β-barrel proteins are found exclusively in the OM where they form pores allowing the passage of nutrients, waste products and signals. One porin, Oar, is required for intercellular communication of the C-signal. An oar mutant produces CsgA but is unable to ripple or stimulate csgA mutants to develop suggesting that it is the channel for C-signaling. Six prediction programs were evaluated for their ability to identify β-barrel proteins. No program was reliable unless the predicted proteins were first parsed using Signal P, Lipo P and TMHMM, after which TMBETA-SVM and TMBETADISC-RBF identified β-barrel proteins most accurately. 228 β-barrel proteins were predicted from among 7331 protein coding regions, representing 3.1% of total genes. Sucrose density gradients were used to separate vegetative cell IM and OM fractions, and LC-MS/MS of OM proteins identified 54 β-barrel proteins. Another class of membrane proteins, the lipoproteins, are anchored in the membrane via a lipid moiety at the N-terminus. 44 OM proteins identified by LC-MS/MS were predicted lipoproteins. Lipoproteins are distributed between the IM, OM and ECM according to an N-terminal sorting sequence that varies among species. Sequence analysis revealed conservation of alanine at the +7 position of mature ECM lipoproteins, lysine at the +2 position of IM lipoproteins, and no noticable conservation within the OM lipoproteins. Site directed mutagenesis and immuno transmission electron microscopy showed that alanine at the +7 position is essential for sorting of the lipoprotein FibA into the ECM. FibA appears at normal levels in the ECM even when a +2 lysine is added to the signal sequence. These results suggest that ECM proteins have a unique method of secretion. It is now possible to target lipoproteins to specific IM, OM and ECM locations by manipulating the amino acid

Relationship between Serum Lipoprotein Ratios and Insulin Resistance in Polycystic Ovary Syndrome

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Shou-Kui Xiang

2012-01-01

Full Text Available Objective. To investigate the association between serum lipoprotein ratios and insulin resistance in women with polycystic ovarian syndrome (PCOS. Methods. 105 PCOS patients and 109 controls were randomly enrolled in the study. Serum levels of luteinizing hormone (LH, follicle-stimulating hormone (FSH, estradiol (E2, total testosterone (T, fasting glucose (FBG, fasting insulin (FINS, serum triglycerides (TG, total cholesterol (TC, high-density lipoprotein (HDL-C, and low-density lipoprotein (LDL-C levels were checked, and then TG/HDL-C ratio, TC/HDL-C, ratio and LDL-C/HDL-C ratio were calculated. The homeostasis model assessment of insulin resistance (HOMA-IR was used to calculate the insulin resistance. Results. All lipoprotein ratios were significantly higher in PCOS patients as compared to healthy controls (<0.05. TG/HDL-C ratio, TC/HDL-C ratio, and LDL-C/HDL-C ratio were significantly correlated with HOMA-IR (<0.05. The ROC curve demonstrated that TC/HDL-C ratio had higher sensitivity and specificity in diagnosing PCOS with insulin resistance. Conclusion. This study demonstrates that serum lipoprotein ratio significantly correlates with insulin resistance and can be used as the marker of insulin resistance in PCOS patients.

Lipoprotein-a

Science.gov (United States)

... this page: //medlineplus.gov/ency/article/007262.htm Lipoprotein-a To use the sharing features on this page, please enable JavaScript. Lipoproteins are molecules made of proteins and fat. They ...

The Human Pathogen Streptococcus pyogenes Releases Lipoproteins as Lipoprotein-rich Membrane Vesicles.

Science.gov (United States)

Biagini, Massimiliano; Garibaldi, Manuela; Aprea, Susanna; Pezzicoli, Alfredo; Doro, Francesco; Becherelli, Marco; Taddei, Anna Rita; Tani, Chiara; Tavarini, Simona; Mora, Marirosa; Teti, Giuseppe; D'Oro, Ugo; Nuti, Sandra; Soriani, Marco; Margarit, Immaculada; Rappuoli, Rino; Grandi, Guido; Norais, Nathalie

2015-08-01

Bacterial lipoproteins are attractive vaccine candidates because they represent a major class of cell surface-exposed proteins in many bacteria and are considered as potential pathogen-associated molecular patterns sensed by Toll-like receptors with built-in adjuvanticity. Although Gram-negative lipoproteins have been extensively characterized, little is known about Gram-positive lipoproteins. We isolated from Streptococcus pyogenes a large amount of lipoproteins organized in vesicles. These vesicles were obtained by weakening the bacterial cell wall with a sublethal concentration of penicillin. Lipid and proteomic analysis of the vesicles revealed that they were enriched in phosphatidylglycerol and almost exclusively composed of lipoproteins. In association with lipoproteins, a few hypothetical proteins, penicillin-binding proteins, and several members of the ExPortal, a membrane microdomain responsible for the maturation of secreted proteins, were identified. The typical lipidic moiety was apparently not necessary for lipoprotein insertion in the vesicle bilayer because they were also recovered from the isogenic diacylglyceryl transferase deletion mutant. The vesicles were not able to activate specific Toll-like receptor 2, indicating that lipoproteins organized in these vesicular structures do not act as pathogen-associated molecular patterns. In light of these findings, we propose to name these new structures Lipoprotein-rich Membrane Vesicles. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

Lipoprotein Apheresis for Lipoprotein(a)-Associated Cardiovascular Disease

DEFF Research Database (Denmark)

Roeseler, Eberhard; Julius, Ulrich; Heigl, Franz

2016-01-01

OBJECTIVE: Lipoprotein(a)-hyperlipoproteinemia (Lp(a)-HLP) along with progressive cardiovascular disease has been approved as indication for regular lipoprotein apheresis (LA) in Germany since 2008. We aimed to study the long-term preventive effect of LA and to assess hypothetical clinical correl...

Crystallization and preliminary diffraction analysis of a DsbA homologue from Wolbachia pipientis

Energy Technology Data Exchange (ETDEWEB)

Kurz, M. [Institute for Molecular Bioscience and ARC Special Research Centre for Functional and Applied Genomics, University of Queensland, St Lucia, QLD 4072 (Australia); Iturbe-Ormaetxe, I. [School of Integrative Biology, The University of Queensland, St Lucia, QLD 4072 (Australia); Jarrott, R. [Institute for Molecular Bioscience and ARC Special Research Centre for Functional and Applied Genomics, University of Queensland, St Lucia, QLD 4072 (Australia); O’Neill, S. L. [School of Integrative Biology, The University of Queensland, St Lucia, QLD 4072 (Australia); Byriel, K. A.; Martin, J. L., E-mail: j.martin@imb.uq.edu.au; Heras, B., E-mail: j.martin@imb.uq.edu.au [Institute for Molecular Bioscience and ARC Special Research Centre for Functional and Applied Genomics, University of Queensland, St Lucia, QLD 4072 (Australia)

2008-02-01

The first crystallization of a W. pipientis protein, α-DsbA1, was achieved using hanging-drop and sitting-drop vapour diffusion. α-DsbA1 is one of two DsbA homologues encoded by the Gram-negative α-proteobacterium Wolbachia pipientis, an endosymbiont that can behave as a reproductive parasite in insects and as a mutualist in medically important filarial nematodes. The α-DsbA1 protein is thought to be important for the folding and secretion of Wolbachia proteins involved in the induction of reproductive distortions. Crystals of native and SeMet α-DsbA1 were grown by vapour diffusion and belong to the monoclinic space group C2, with unit-cell parameters a = 71.4, b = 49.5, c = 69.3 Å, β = 107.0° and one molecule in the asymmetric unit (44% solvent content). X-ray data were recorded from native crystals to a resolution of 2.01 Å using a copper anode and data from SeMet α-DsbA1 crystals were recorded to 2.45 Å resolution using a chromium anode.

Contribution of lipoproteins and lipoprotein processing to endocarditis virulence in Streptococcus sanguinis.

Science.gov (United States)

Das, Sankar; Kanamoto, Taisei; Ge, Xiuchun; Xu, Ping; Unoki, Takeshi; Munro, Cindy L; Kitten, Todd

2009-07-01

Streptococcus sanguinis is an important cause of infective endocarditis. Previous studies have identified lipoproteins as virulence determinants in other streptococcal species. Using a bioinformatic approach, we identified 52 putative lipoprotein genes in S. sanguinis strain SK36 as well as genes encoding the lipoprotein-processing enzymes prolipoprotein diacylglyceryl transferase (lgt) and signal peptidase II (lspA). We employed a directed signature-tagged mutagenesis approach to systematically disrupt these genes and screen each mutant for the loss of virulence in an animal model of endocarditis. All mutants were viable. In competitive index assays, mutation of a putative phosphate transporter reduced in vivo competitiveness by 14-fold but also reduced in vitro viability by more than 20-fold. Mutations in lgt, lspA, or an uncharacterized lipoprotein gene reduced competitiveness by two- to threefold in the animal model and in broth culture. Mutation of ssaB, encoding a putative metal transporter, produced a similar effect in culture but reduced in vivo competiveness by >1,000-fold. [(3)H]palmitate labeling and Western blot analysis confirmed that the lgt mutant failed to acylate lipoproteins, that the lspA mutant had a general defect in lipoprotein cleavage, and that SsaB was processed differently in both mutants. These results indicate that the loss of a single lipoprotein, SsaB, dramatically reduces endocarditis virulence, whereas the loss of most other lipoproteins or of normal lipoprotein processing has no more than a minor effect on virulence.

Global genetic variation in the Asian citrus psyllid, Diaphorina citri (Hemiptera: Liviidae) and the endosymbiont Wolbachia: links between Iran and the USA detected.

Science.gov (United States)

Lashkari, Mohammadreza; Manzari, Shahab; Sahragard, Ahad; Malagnini, Valeria; Boykin, Laura M; Hosseini, Reza

2014-07-01

The Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae), is one of the most serious pests of citrus in the world, because it transmits the pathogen that causes citrus greening disease. To determine genetic variation among geographic populations of D. citri, microsatellite markers, mitochondrial gene cytochrome oxidase I (mtCOI) and the Wolbachia-Diaphorina, wDi, gene wsp sequence data were used to characterize Iranian and Pakistani populations. Also, a Bayesian phylogenetic technique was utilized to elucidate the relationships among the sequences data in this study and all mtCOI and wsp sequence data available in GenBank and the Wolbachia database. Microsatellite markers revealed significant genetic differentiation among Iranian populations, as well as between Iranian and Pakistani populations (FST  = 0.0428, p citri populations in Iran, India, Saudi Arabia, Brazil, Mexico, Florida and Texas (USA) are similar. Wolbachia, wDi, wsp sequences were similar among Iranian populations, but different between Iranian and Pakistani populations. The South West Asia (SWA) group is the most likely source of the introduced Iranian populations of D. citri. This assertion is also supported by the sequence similarity of the Wolbachia, wDi, strains from the Florida, USA and Iranian D. citri. These results should be considered when looking for biological controls in either country. © 2013 Society of Chemical Industry.

The majority of lipoprotein lipase in plasma is bound to remnant lipoproteins: A new definition of remnant lipoproteins.

Science.gov (United States)

Sato, Koichi; Okajima, Fumikazu; Miyashita, Kazuya; Imamura, Shigeyuki; Kobayashi, Junji; Stanhope, Kimber L; Havel, Peter J; Machida, Tetsuo; Sumino, Hiroyuki; Murakami, Masami; Schaefer, Ernst; Nakajima, Katsuyuki

2016-10-01

Lipoprotein lipase (LPL) is a multifunctional protein and a key enzyme involved in the regulation of lipoprotein metabolism. We determined the lipoproteins to which LPL is bound in the pre-heparin and post-heparin plasma. Tetrahydrolipstatin (THL), a potent inhibitor of serine lipases, was used to block the lipolytic activity of LPL, thereby preventing changes in the plasma lipoproteins due to ex vivo lipolysis. Gel filtration was performed to obtain the LPL elution profiles in plasma and the isolated remnant lipoproteins (RLP). When ex vivo lipolytic activity was inhibited by THL in the post-heparin plasma, majority of the LPL was found in the VLDL elution range, specifically in the RLP as inactive dimers. However, in the absence of THL, most of the LPL was found in the HDL elution range as active dimers. Furthermore, majority of the LPL in the pre-heparin plasma was found in the RLP as inactive form, with broadly diffused lipoprotein profiles in the presence and absence of THL. It is suggested that during lipolysis in vivo, the endothelial bound LPL dimers generates RLP, forming circulating RLP-LPL complexes in an inactive form that subsequently binds and initiates receptor-mediated catabolism. Copyright © 2016 Elsevier B.V. All rights reserved.

Culex pipiens crossing type diversity is governed by an amplified and polymorphic operon of Wolbachia.

Science.gov (United States)

Bonneau, Manon; Atyame, Celestine; Beji, Marwa; Justy, Fabienne; Cohen-Gonsaud, Martin; Sicard, Mathieu; Weill, Mylène

2018-01-22

Culex pipiens mosquitoes are infected with Wolbachia (wPip) that cause an important diversity of cytoplasmic incompatibilities (CIs). Functional transgenic studies have implicated the cidA-cidB operon from wPip and its homolog in wMel in CI between infected Drosophila males and uninfected females. However, the genetic basis of the CI diversity induced by different Wolbachia strains was unknown. We show here that the remarkable diversity of CI in the C. pipiens complex is due to the presence, in all tested wPip genomes, of several copies of the cidA-cidB operon, which undergoes diversification through recombination events. In 183 isofemale lines of C. pipiens collected worldwide, specific variations of the cidA-cidB gene repertoires are found to match crossing types. The diversification of cidA-cidB is consistent with the hypothesis of a toxin-antitoxin system in which the gene cidB co-diversifies with the gene cidA, particularly in putative domains of reciprocal interactions.

Application of wMelPop Wolbachia Strain to Crash Local Populations of Aedes aegypti.

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Scott A Ritchie

Full Text Available The endosymbiotic bacteria Wolbachia pipientis (wMel strain has been successfully established in several populations of Aedes aegypti, the primary dengue vector. The virulent Wolbachia strain wMelPop is known to cause several pathological impacts (increased egg mortality, life shortening, etc. reducing overall fitness in the mosquito Ae. aegypti. Increased egg mortality could substantially reduce egg banks in areas with a lengthy monsoonal dry season, and be employed to eliminate local populations. We tested this application under semi-field cage conditions. First, we determined that wMelPop infection significantly reduced the survival of desiccation-resistant eggs of the dengue vector Ae. aegypti, with shade and temperature having a significant impact; nearly all wMelPop-infected eggs failed to hatch after 6 and 10 weeks in summer and winter conditions, respectively. In laboratory selection experiments we found that egg desiccation resistance can be increased by selection, and that this effect of wMelPop infection is due to the nuclear background of the host rather than Wolbachia. We then conducted an invasion of wMelPop within a semi-field cage using sustained weekly releases of wMelPop infected mosquitoes, with fixation achieved after 9 weeks. The egg populations wMelPop infected and an uninfected control were then subjected to a simulated prolonged monsoonal dry season (2.5 months before flooding to induce hatching. The wMelPop infected eggs suffered significantly greater mortality than the controls, with only 0.67% and 4.35% of respective infected and uninfected eggs held in 99% shade hatching after 80 days. These studies suggest that wMelPop could be used to locally eliminate populations of Ae. aegypti that are exposed to prolonged dry conditions, particularly if combined with vector control.

Streptococcus gordonii induces nitric oxide production through its lipoproteins stimulating Toll-like receptor 2 in murine macrophages.

Science.gov (United States)

Kim, Hyun Young; Baik, Jung Eun; Ahn, Ki Bum; Seo, Ho Seong; Yun, Cheol-Heui; Han, Seung Hyun

2017-02-01

Streptococcus gordonii, a Gram-positive commensal in the oral cavity, is an opportunistic pathogen that can cause endodontic and systemic infections resulting in infective endocarditis. Lipoteichoic acid (LTA) and lipoprotein are major virulence factors of Gram-positive bacteria that are preferentially recognized by Toll-like receptor 2 (TLR2) on immune cells. In the present study, we investigated the effect of S. gordonii LTA and lipoprotein on the production of the representative inflammatory mediator nitric oxide (NO) by the mouse macrophages. Heat-killed S. gordonii wild-type and an LTA-deficient mutant (ΔltaS) but not a lipoprotein-deficient mutant (Δlgt) induced NO production in mouse primary macrophages and the cell line, RAW 264.7. S. gordonii wild-type and ΔltaS also induced the expression of inducible NO synthase (iNOS) at the mRNA and protein levels. In contrast, the Δlgt mutant showed little effect under the same condition. Furthermore, S. gordonii wild-type and ΔltaS induced NF-κB activation, STAT1 phosphorylation, and IFN-β expression, which are important for the induction of iNOS gene expression, with little activation by Δlgt. S. gordonii wild-type and ΔltaS showed an increased adherence and internalization to RAW 264.7 cells compared to Δlgt. In addition, S. gordonii wild-type and ΔltaS, but not Δlgt, substantially increased TLR2 activation while none of these induced NO production in TLR2-deficient macrophages. Triton X-114-extracted lipoproteins from S. gordonii were sufficient to induce NO production. Collectively, we suggest that lipoprotein is an essential cell wall component of S. gordonii to induce NO production in macrophages through TLR2 triggering NF-κB and STAT1 activation. Copyright © 2016 Elsevier Ltd. All rights reserved.

Contribution of Lipoproteins and Lipoprotein Processing to Endocarditis Virulence in Streptococcus sanguinis▿ §

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Das, Sankar; Kanamoto, Taisei; Ge, Xiuchun; Xu, Ping; Unoki, Takeshi; Munro, Cindy L.; Kitten, Todd

2009-01-01

Streptococcus sanguinis is an important cause of infective endocarditis. Previous studies have identified lipoproteins as virulence determinants in other streptococcal species. Using a bioinformatic approach, we identified 52 putative lipoprotein genes in S. sanguinis strain SK36 as well as genes encoding the lipoprotein-processing enzymes prolipoprotein diacylglyceryl transferase (lgt) and signal peptidase II (lspA). We employed a directed signature-tagged mutagenesis approach to systematically disrupt these genes and screen each mutant for the loss of virulence in an animal model of endocarditis. All mutants were viable. In competitive index assays, mutation of a putative phosphate transporter reduced in vivo competitiveness by 14-fold but also reduced in vitro viability by more than 20-fold. Mutations in lgt, lspA, or an uncharacterized lipoprotein gene reduced competitiveness by two- to threefold in the animal model and in broth culture. Mutation of ssaB, encoding a putative metal transporter, produced a similar effect in culture but reduced in vivo competiveness by >1,000-fold. [3H]palmitate labeling and Western blot analysis confirmed that the lgt mutant failed to acylate lipoproteins, that the lspA mutant had a general defect in lipoprotein cleavage, and that SsaB was processed differently in both mutants. These results indicate that the loss of a single lipoprotein, SsaB, dramatically reduces endocarditis virulence, whereas the loss of most other lipoproteins or of normal lipoprotein processing has no more than a minor effect on virulence. PMID:19395487

Lipoprotein profile, lipoprotein-associated phospholipase A2 and cardiovascular risk in hemodialysis patients.

Science.gov (United States)

Rolla, Roberta; De Mauri, Andreana; Valsesia, Ambra; Vidali, Matteo; Chiarinotti, Doriana; Bellomo, Giorgio

2015-12-01

Cardiovascular disease is the leading cause of morbidity and mortality in hemodialysis patients; the increased risk of cardiovascular disease is due to accelerated atherosclerosis, inflammation and impaired lipoprotein metabolism. We aimed to evaluate lipoprotein-associated phospholipase A2 (Lp-PLA2) and some pro-inflammatory aspects of the lipoprotein profile in dialyzed patients in order to evaluate the relationship with the accelerated atherosclerosis and vascular accidents. In 102 dialysis patients and 40 non-uremic controls, we investigated the lipoprotein plasma profile, high sensitivity C-reactive protein (CRP), ceruloplasmin and serum amyloid A protein (SAA), and followed patients for 1 year to analyze the risk of acute cardiovascular events. Total cholesterol, low-density lipoprotein and high-density lipoprotein plasma levels were significantly lower in uremic patients than controls, whereas CRP, SAA, ceruloplasmin, Lp-PLA2 and their ratio with apolipoprotein A1 were significantly higher. Patients with Lp-PLA2 levels >194 nmol/min/ml had more acute cardiovascular events than patients with lower values. Our results show that in dialysis subjects: (1) low-density lipoproteins show a more atherogenic phenotype than in the general population; (2) high-density lipoproteins are less anti-inflammatory; (3) Lp-PLA2 could potentially be used to evaluate cardiovascular risk.

Family level variation in Wolbachia-mediated dengue virus blocking in Aedes aegypti

OpenAIRE

Terradas, Gerard; Allen, Scott L.; Chenoweth, Stephen F.; McGraw, Elizabeth A.

2017-01-01

Background The mosquito vector Aedes aegypti is responsible for transmitting a range of arboviruses including dengue (DENV) and Zika (ZIKV). The global reach of these viruses is increasing due to an expansion of the mosquito’s geographic range and increasing urbanization and human travel. Vector control remains the primary means for limiting these diseases. Wolbachia pipientis is an endosymbiotic bacterium of insects that has the ability to block the replication of pathogens, including flaviv...

Decision-making in a bisexual line and a thelytokous Wolbachia-infected line of Trichogramma dendrolimi Matsumura (Hymenoptera: Trichogrammatidae) regarding behavior toward their hosts.

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Liu, Quan-Quan; Zhang, Tong-Shu; Li, Chun-Xue; Gu, Jun-Wen; Hou, Jie-Bin; Dong, Hui

2018-07-01

The use of thelytokous Wolbachia-infected Trichogramma (parasitic wasps) has long been considered as a way to enhance the efficacy of biocontrol. However, Wolbachia can affect the host physiology. We compared decision-making between bisexual and thelytokous Wolbachia-infected lines of Trichogramma dendrolimi Matsumura regarding behavior toward fresh and old eggs of Corcyra cephalonica at 25 ± 1 °C and 70 ± 5% relative humidity. The behavioral patterns and sequences of the two lines were basically the same. The durations of various behavioral patterns and values of fitness indicators of the bisexual line on fresh eggs were generally significantly shorter and better, respectively, than on old eggs, whereas the thelytokous line behaved similarly toward the two types of eggs, and differences in most fitness indicators between fresh and old eggs were not significant. On fresh eggs, the durations of various behaviors in the bisexual line were generally significantly shorter than in the thelytokous line and the fitness indicators were generally significantly better. Wolbachia affected the fitness of T. dendrolimi negatively. The potential of the thelytokous line as a biocontrol agent would not be as good as that of the bisexual line when decision-making only is considered. Therefore, further evaluations need to be carried out before the thelytokous line can be used in practical biocontrol. © 2018 Society of Chemical Industry. © 2018 Society of Chemical Industry.

Effect of phospholipase A treatment of low density lipoproteins on the dextran sulfate--lipoprotein interaction.

Science.gov (United States)

Nishida, T

1968-09-01

The effect of phospholipase A on the interaction of low density lipoproteins of the S(f) 0-10 class with dextran sulfate was studied in phosphate buffer of pH 7.4, ionic strength 0.1, by chemical, spectrophotometric, and centrifugal methods. When low density lipoproteins that had been treated with phospholipase A were substituted for untreated lipoproteins, the amount of insoluble dextran sulfate-lipoprotein complex formed was greatly reduced. Hydrolysis of over 20% of the lecithin and phosphatidyl ethanolamine constituents of the lipoproteins prevented the formation of insoluble complex. However, even the lipoproteins in which almost all the phosphoglycerides were hydrolyzed produced soluble complex, which was converted to insoluble complex upon addition of magnesium sulfate. It is apparent that the lipoproteins altered extensively by treatment with phospholipase A retain many characteristic properties of native low density lipoproteins. Fatty acids, but not lysolecithin, released by the action of phospholipase A interfered with the formation of insoluble complex; this interference was due to association of the fatty acids with the lipoproteins. With increases in the concentration of the associated fatty acids, the amounts of magnesium ion required for the conversion of soluble complex to insoluble complex increased progressively. Charge interaction is evidently of paramount importance in the formation of sulfated polysaccharide-lipoprotein complexes.

Phosphatidylinositol response and proliferation of oxidative enzyme-activated human T lymphocytes: suppression by plasma lipoproteins

International Nuclear Information System (INIS)

Akeson, A.L.; Scupham, D.W.; Harmony, J.A.

1984-01-01

The phosphatidylinositol (PI) response and DNA synthesis of neuraminidase and galactose oxidase (NAGO)-stimulated human T lymphocytes are suppressed by low density lipoproteins (LDL). To understand the mechanism of lymphocyte activation more fully, the PI response and DNA synthesis and suppression of these events by LDL in NAGO-stimulated T lymphocytes were characterized. Between 30 min and 6 hr after NAGO stimulation, there was an increase of 32 Pi incorporation into PI without increased incorporation into the phosphorylated forms of PI or into other phospholipids. DNA synthesis as determined by [ 3 H]thymidine incorporation depended on the lymphocyte-accessory monocyte ratio and total cell density. Optimal stimulation of the PI response and DNA synthesis occurred at the same concentration of neuraminidase and galactose oxidase. While the PI response was only partially suppressed by LDL with optimal suppression at 10 to 20 micrograms of protein/ml, DNA synthesis was completely suppressed although at much higher LDL concentrations, greater than 100 micrograms protein/ml. As monocyte numbers are increased, LDL suppression of DNA synthesis is decreased. The ability of NAGO to stimulate the PI response and DNA synthesis in a similar way, and the suppression of both events by LDL, suggests the PI response is important for lymphocyte activation and proliferation. Stimulation of human T lymphocytes by oxidative mitogens, neuraminidase, and galactose oxidase caused increased phosphatidylinositol metabolism and increased DNA synthesis. Both responses were suppressed by low density lipoproteins

Liver lipase and high-density lipoprotein. Lipoprotein changes after incubation of human serum with rat liver lipase.

Science.gov (United States)

Groot, P H; Scheek, L M; Jansen, H

1983-05-16

Human sera were incubated with rat liver lipase after inactivation of lecithin:cholesterol acyltransferase, and the changes in serum lipoprotein composition were measured. In the presence of liver lipase serum triacylglycerol and phosphatidylcholine were hydrolyzed. The main changes in the concentrations of these lipids were found in the high-density lipoprotein fraction. Subfractionation of high-density lipoprotein by rate-zonal ultracentrifugation showed a prominent decrease in all constituents of high-density lipoprotein2, a smaller decrease in the 'light' high-density lipoprotein3 and an increase in the 'heavy' high-density lipoprotein3. These data support a concept in which liver lipase is involved in high-density lipoprotein2 phospholipid and triacylglycerol catabolism and suggest that as a result of this action high-density lipoprotein2 is converted into high-density lipoprotein3.

Biogenesis and Membrane Targeting of Lipoproteins.

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Narita, Shin-Ichiro; Tokuda, Hajime

2010-09-01

Bacterial lipoproteins represent a unique class of membrane proteins, which are anchored to membranes through triacyl chains attached to the amino-terminal cysteine. They are involved in various functions localized in cell envelope. Escherichia coli possesses more than 90 species of lipoproteins, most of which are localized in the outer membrane, with others being in the inner membrane. All lipoproteins are synthesized in the cytoplasm with an N-terminal signal peptide, translocated across the inner membrane by the Sec translocon to the periplasmic surface of the inner membrane, and converted to mature lipoproteins through sequential reactions catalyzed by three lipoprotein-processing enzymes: Lgt, LspA, and Lnt. The sorting of lipoproteins to the outer membrane requires a system comprising five Lol proteins. An ATP-binding cassette transporter, LolCDE, initiates the sorting by mediating the detachment of lipoproteins from the inner membrane. Formation of the LolA-lipoprotein complex is coupled to this LolCDE-dependent release reaction. LolA accommodates the amino-terminal acyl chain of lipoproteins in its hydrophobic cavity, thereby generating a hydrophilic complex that can traverse the periplasmic space by diffusion. Lipoproteins are then transferred to LolB on the outer membrane and anchored to the inner leaflet of the outer membrane by the action of LolB. In contrast, since LolCDE does not recognize lipoproteins possessing Asp at position +2, these lipoproteins remain anchored to the inner membrane. Genes for Lol proteins are widely conserved among gram-negative bacteria, and Lol-mediated outer membrane targeting of lipoproteins is considered to be the general lipoprotein localization mechanism.

Single-Particle Tracking of Human Lipoproteins.

Science.gov (United States)

de Messieres, Michel; Ng, Abby; Duarte, Cornelio J; Remaley, Alan T; Lee, Jennifer C

2016-01-05

Lipoproteins, such as high-density lipoprotein (HDL), low-density lipoprotein (LDL), and very-low density lipoprotein (VLDL), play a critical role in heart disease. Lipoproteins vary in size and shape as well as in their apolipoprotein content. Here, we developed a new experimental framework to study freely diffusing lipoproteins from human blood, allowing analysis of even the smallest HDL with a radius of 5 nm. In an easily constructed confinement chamber, individual HDL, LDL, and VLDL particles labeled with three distinct fluorophores were simultaneously tracked by wide-field fluorescence microscopy and their sizes were determined by their motion. This technique enables studies of individual lipoproteins in solution and allows characterization of the heterogeneous properties of lipoproteins which affect their biological function but are difficult to discern in bulk studies.

Bacterial Infections across the Ants: Frequency and Prevalence of Wolbachia, Spiroplasma, and Asaia

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Stefanie Kautz

2013-01-01

Full Text Available Bacterial endosymbionts are common across insects, but we often lack a deeper knowledge of their prevalence across most organisms. Next-generation sequencing approaches can characterize bacterial diversity associated with a host and at the same time facilitate the fast and simultaneous screening of infectious bacteria. In this study, we used 16S rRNA tag encoded amplicon pyrosequencing to survey bacterial communities of 310 samples representing 221 individuals, 176 colonies and 95 species of ants. We found three distinct endosymbiont groups—Wolbachia (Alphaproteobacteria: Rickettsiales, Spiroplasma (Firmicutes: Entomoplasmatales, and relatives of Asaia (Alphaproteobacteria: Rhodospirillales—at different infection frequencies (at the ant species level: 22.1%, 28.4%, and 14.7%, resp. and relative abundances within bacterial communities (1.0%–99.9%. Spiroplasma was particularly enriched in the ant genus Polyrhachis, while Asaia relatives were most prevalent in arboreal ants of the genus Pseudomyrmex. While Wolbachia and Spiroplasma have been surveyed in ants before, Asaia, an acetic acid bacterium capable of fixing atmospheric nitrogen, has received much less attention. Due to sporadic prevalence across all ant taxa investigated, we hypothesize facultative associations for all three bacterial genera. Infection patterns are discussed in relation to potential adaptation of specific bacteria in certain ant groups.

Lipoprotein(a) and dietary proteins: casein lowers lipoprotein(a) concentrations as compared with soy protein1-3

DEFF Research Database (Denmark)

Nilausen, Karin Johanne; Meinertz, H.

1999-01-01

Lipoprotein(a), plasma lipoproteins, dietary proteins, soy protein, casein, liquid-formula, coronary artery disease, men, Denmark......Lipoprotein(a), plasma lipoproteins, dietary proteins, soy protein, casein, liquid-formula, coronary artery disease, men, Denmark...

Lipoprotein glomerulopathy treated with LDL-apheresis (Heparin-induced Extracorporeal Lipoprotein Precipitation system: a case report

Directory of Open Access Journals (Sweden)

Rivasi Paolo

2009-12-01

Full Text Available Abstract Introduction Lipoprotein glomerulopathy is a glomerulonephritis which was described for the first time by Saito in 1989 and is currently acknowledged as a separate nosological entity. It is histologically characterized by a marked dilatation of the glomerular capillaries and the presence of lipoprotein thrombi in the glomerular lumens. The dyslipidemic profile is similar to that of type III dyslipoproteinemia with Apolipoprotein E values that are often high; proteinuria and renal dysfunction are present. Proteinuria often does not respond to steroid and cytostatic treatments. The phenotypic expression of lipoprotein glomerulopathy is most probably correlated to a genetic alteration of the lipoprotein metabolism (mutation of the Apolipoprotein E coding gene. In literature, lipoprotein glomerulopathies have mainly been reported in Japanese and Chinese subjects, except for three cases in the Caucasian race, reported in France and the USA. Case presentation We describe the case of a 60-year-old female, Caucasian patient suffering from lipoprotein glomerulopathy, carrier of a new mutation on the Apolipoprotein E gene (Apolipoprotein EMODENA, and treated successfully with low density lipoprotein-apheresis with the Heparin induced extracorporeal lipoprotein precipitation system. After a first phase of therapeutic protocol with statins, the patient was admitted for nephrotic syndrome, renal failure and hypertension. Since conventional treatment alone was not able to control dyslipidemia, aphaeretic treatment with heparin-induced Extracorporeal Lipoprotein Precipitation - apheresis (HELP-apheresis was started to maintain angiotensin converting enzyme inhibitor therapy for the treatment of hypertension. Treatment with HELP-apheresis led to a complete remission of the proteinuria in a very short time (four months, as well as control of hypercholesterolemia and renal function recovery. Conclusion According to this case of lipoprotein glomerulopathy

Staphylococcus aureus lipoproteins trigger human corneal epithelial innate response through toll-like receptor-2.

Science.gov (United States)

Li, Qiong; Kumar, Ashok; Gui, Jian-Fang; Yu, Fu-Shin X

2008-05-01

Bacterial lipoproteins (LP) are a family of cell wall components found in a wide variety of bacteria. In this study, we characterized the response of HUCL, a telomerase-immortalized human corneal epithelial cell (HCEC) line, to LP isolated from Staphylococcus (S) aureus. S. aureus LP (saLP) prepared by Triton X-114 extraction stimulated the activation of NF-kappaB, JNK, and P38 signaling pathways in HUCL cells. The extracts failed to stimulate NF-kappaB activation in HUCL cells after lipoprotein lipase treatment and in cell lines expressing TLR4 or TLR9, but not TLR2, indicating lipoprotein nature of the extracts. saLP induced the up-regulation of a variety of inflammatory cytokines and chemokines (IL-6, IL-8, ICAM-1), antimicrobial molecules (hBD-2, LL-37, and iNOS), and homeostasis genes (Mn-SOD) at both the mRNA level and protein level. Similar inflammatory response to saLP was also observed in primarily cultured HCECs using the production of IL-6 as readout. Moreover, TLR2 neutralizing antibody blocked the saLP-induced secretion of IL-6, IL-8 and hBD2 in HUCL cells. Our findings suggest that saLP activates TLR2 and triggers innate immune response in the cornea to S. aureus infection via production of proinflammatory cytokines and defense molecules.

Combined analysis of six lipoprotein lipase genetic variants on triglycerides, high-density lipoprotein, and ischemic heart disease

DEFF Research Database (Denmark)

Wittrup, Hans H; Andersen, Rolf V; Tybjaerg-Hansen, Anne

2006-01-01

Genetic variants in lipoprotein lipase may affect triglycerides, high-density lipoprotein (HDL), and risk of ischemic heart disease (IHD).......Genetic variants in lipoprotein lipase may affect triglycerides, high-density lipoprotein (HDL), and risk of ischemic heart disease (IHD)....

Wolbachia infections mimic cryptic speciation in two parasitic butterfly species, Phengaris teleius and P. nausithous (Lepidoptera: Lycaenidae)

Czech Academy of Sciences Publication Activity Database

Ritter, S.; Michalski, S. G.; Settele, J.; Wiemers, M.; Fric, Zdeněk; Sielezniew, M.; Šašić, M.; Rozier, Y.; Durka, W.

2013-01-01

Roč. 8, č. 11 (2013), e78107 E-ISSN 1932-6203 Institutional support: RVO:60077344 Keywords : Wolbachia Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 3.534, year: 2013 http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0078107

Heparin induces an accumulation of atherogenic lipoproteins during hemodialysis in normolipidemic end-stage renal disease patients.

Science.gov (United States)

Barbagallo, Carlo M; Noto, Davide; Cefalù, Angelo B; Ganci, Antonia; Giammarresi, Carlo; Panno, Donata; Cusumano, Gaspare; Greco, Massimiliano; Di Gaudio, Francesca; Averna, Maurizio R

2015-07-01

Dyslipidemias may account for the excess of cardiovascular mortality in end-stage renal disease (ESRD). Lipoprotein studies in ESRD patients are usually relative to prehemodialysis samples even if significative changes may occur after dialysis. In this study, we aimed to investigate the effects of ESRD on triglyceride-rich lipoproteins (TRL) subpopulations distribution and acute change following hemodialytic procedures, including the relative contribution of heparin administration. We selected a group of normolipidemic male middle-aged ESRD patients free of any concomitant disease affecting lipoprotein remnant metabolism compared with controls. We separated TRL subfractions according to density and apoE content and evaluated the changes of these particles after hemodialytic procedures with or without heparin. ESRD subjects had higher TRL subfractions, with the exception of apoE-rich particles, lower high-density lipoprotein (HDL) largest subclasses, and a smaller low-density lipoprotein peak particle size than controls. After a hemodialytic standard procedure with heparin, we demonstrated a significant reduction of triglyceride, an increase of HDL-cholesterol levels, and a raise of small very-low-density lipoprotein, intermediate-density lipoproteins (IDL), apoE-rich particles, and non-HDL-cholesterol levels. When hemodialysis was performed without heparin, no significant changes were observed. In the absence of concomitant hyperlipidemic triggers, ESRD patients show significant lipoprotein abnormalities before dialysis, but without any increased remnant particles concentrations. We speculate that hemodialysis, in particular heparin administration during this procedure, leads to a massive atherogenic TRLs production because of the acute stimulation of the dysfunctional lipolytic system not followed by an efficient removal, determining a recurrent lipoprotein remnant accumulation. © 2014 International Society for Hemodialysis.

Genetic variation and potential coinfection of Wolbachia among widespread Asian citrus psyllid (Diaphorina citri Kuwayama) populations.

Science.gov (United States)

Chu, Chia-Ching; Hoffmann, Mark; Braswell, W Evan; Pelz-Stelinski, Kirsten S

2017-12-29

Wolbachia can profoundly influence the survival, reproduction, and defenses of insect hosts. These interactions could potentially be harnessed for managing pests or insect-transmitted diseases. Diaphorina citri Kuwayama is a phloem-feeding pest capable of transmitting the putative causal agent of citrus greening, Candidatus Liberibacter asiaticus (CLas). Like many insects, D. citri is also infected with Wolbachia (wDi). Recent studies indicate that the relative abundance of wDi could be associated with the abundance of CLas, and that wDi may contribute to regulating expression of phage lytic cycle genes in CLas, suggesting the need for better understanding of wDi biology in general. This study investigated the genetic diversity of wDi among D. citri in populations spanning eleven countries and two U.S. territories. Six Wolbachia genes, wsp, coxA, fbpA, ftsZ, gatB, and hcpA, were sequenced and compared across samples. Two prevalent wDi strains were identified across the samples, and screening of clone libraries revealed possible coinfection of wDi strains in specific populations. D. citri mitochondrial cytochrome oxidase subunit I gene (mtCOI) were more divergent between D. citri populations that were infected with different wDi strains or had different infection statuses (single infection vs. coinfection). While we could not eliminate the possibility that maternal transmission may contribute to such patterns, it is also possible that wDi may induce cytoplasmic incompatibility in their host. These findings should contribute to the understanding of wDi population ecology, which may facilitate manipulation of this endosymbiont for management of citrus greening disease worldwide. © 2017 The Authors. Insect Science published by John Wiley & Sons Australia, Ltd on behalf of Institute of Zoology, Chinese Academy of Sciences.

Genetic determinants of LDL, lipoprotein(a), triglyceride-rich lipoproteins and HDL: concordance and discordance with cardiovascular disease risk

DEFF Research Database (Denmark)

Nordestgaard, Børge G; Tybjærg-Hansen, Anne

2011-01-01

To evaluate whether new and known genetic determinants of plasma levels of LDL cholesterol, lipoprotein(a), triglyceride-rich lipoproteins, and HDL cholesterol associate with the risk of cardiovascular disease expected from the effect on lipoprotein levels. Concordance or discordance of such gene......To evaluate whether new and known genetic determinants of plasma levels of LDL cholesterol, lipoprotein(a), triglyceride-rich lipoproteins, and HDL cholesterol associate with the risk of cardiovascular disease expected from the effect on lipoprotein levels. Concordance or discordance...

Phytosterols, Phytostanols, and Lipoprotein Metabolism

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Helena Gylling

2015-09-01

Full Text Available The efficacy of phytosterols and phytostanols added to foods and food supplements to obtain significant non-pharmacologic serum and low density lipoprotein (LDL cholesterol reduction is well documented. Irrespective of age, gender, ethnic background, body weight, background diet, or the cause of hypercholesterolemia and, even added to statin treatment, phytosterols and phytostanols at 2 g/day significantly lower LDL cholesterol concentration by 8%–10%. They do not affect the concentrations of high density lipoprotein cholesterol, lipoprotein (a or serum proprotein convertase subtilisin/kexin type 9. In some studies, phytosterols and phytostanols have modestly reduced serum triglyceride levels especially in subjects with slightly increased baseline concentrations. Phytosterols and phytostanols lower LDL cholesterol by displacing cholesterol from mixed micelles in the small intestine so that cholesterol absorption is partially inhibited. Cholesterol absorption and synthesis have been carefully evaluated during phytosterol and phytostanol supplementation. However, only a few lipoprotein kinetic studies have been performed, and they revealed that LDL apoprotein B-100 transport rate was reduced. LDL particle size was unchanged, but small dense LDL cholesterol concentration was reduced. In subjects with metabolic syndrome and moderate hypertriglyceridemia, phytostanols reduced not only non- high density lipoprotein (HDL cholesterol concentration but also serum triglycerides by 27%, and reduced the large and medium size very low density lipoprotein particle concentrations. In the few postprandial studies, the postprandial lipoproteins were reduced, but detailed studies with apoprotein B-48 are lacking. In conclusion, more kinetic studies are required to obtain a more complete understanding of the fasting and postprandial lipoprotein metabolism caused by phytosterols and phytostanols. It seems obvious, however, that the most atherogenic lipoprotein

Phytosterols, Phytostanols, and Lipoprotein Metabolism.

Science.gov (United States)

Gylling, Helena; Simonen, Piia

2015-09-17

The efficacy of phytosterols and phytostanols added to foods and food supplements to obtain significant non-pharmacologic serum and low density lipoprotein (LDL) cholesterol reduction is well documented. Irrespective of age, gender, ethnic background, body weight, background diet, or the cause of hypercholesterolemia and, even added to statin treatment, phytosterols and phytostanols at 2 g/day significantly lower LDL cholesterol concentration by 8%-10%. They do not affect the concentrations of high density lipoprotein cholesterol, lipoprotein (a) or serum proprotein convertase subtilisin/kexin type 9. In some studies, phytosterols and phytostanols have modestly reduced serum triglyceride levels especially in subjects with slightly increased baseline concentrations. Phytosterols and phytostanols lower LDL cholesterol by displacing cholesterol from mixed micelles in the small intestine so that cholesterol absorption is partially inhibited. Cholesterol absorption and synthesis have been carefully evaluated during phytosterol and phytostanol supplementation. However, only a few lipoprotein kinetic studies have been performed, and they revealed that LDL apoprotein B-100 transport rate was reduced. LDL particle size was unchanged, but small dense LDL cholesterol concentration was reduced. In subjects with metabolic syndrome and moderate hypertriglyceridemia, phytostanols reduced not only non- high density lipoprotein (HDL) cholesterol concentration but also serum triglycerides by 27%, and reduced the large and medium size very low density lipoprotein particle concentrations. In the few postprandial studies, the postprandial lipoproteins were reduced, but detailed studies with apoprotein B-48 are lacking. In conclusion, more kinetic studies are required to obtain a more complete understanding of the fasting and postprandial lipoprotein metabolism caused by phytosterols and phytostanols. It seems obvious, however, that the most atherogenic lipoprotein particles will be

Characterization and transcriptional analysis of two gene clusters for type IV secretion machinery in Wolbachia of Armadillidium vulgare

DEFF Research Database (Denmark)

Félix, Christine; Pichon, Samuel; Braquart-Varnier, Christine

2008-01-01

Wolbachia are maternally inherited alpha-proteobacteria that induce feminization of genetic males in most terrestrial crustacean isopods. Two clusters of vir genes for a type IV secretion machinery have been identified at two separate loci and characterized for the first time in a feminizing Wolb...

Onset of lipoprotein-supported steroidogenesis in differentiating granulosa cells of rats: cellular events involved in mediating FSH-enhanced uptake of low-density lipoproteins

International Nuclear Information System (INIS)

Foster, J.D.

1987-01-01

Luteal cells use lipoproteins as the main source of cholesterol in steroidogenesis. However, little is known about the mechanisms underlying hormonal control of lipoprotein uptake. Thus, the authors tested the hypothesis that FSH and androgens regulate low density lipoprotein (LDL)-supported steroidogenesis in maturing granulosa cells by affecting receptor-mediated endocytosis of LDL at a cellular level. For this, immature ovarian granulosa cells were cultured with or without hormones, compactin (de novo synthesis inhibitor), or unlabeled or labeled ( 125 I or gold particles) LDL. Nonhormone-treated cultures produced little progestin; FSH and FSH/androstenedione stimulated steroid secretion. Progestin production by hormone-, but not nonhormone-, treated cultures was decreased by compactin, suggesting that de novo synthesis provided sterol for steroidogenesis. EM quantitation of cells exposed to gold-LDL at 37 0 C revealed that, compared to nonhormone-treated cells, FSH-treated cells (1) bound and internalized more gold-LDL, (2) had a smaller percentage of gold-LDL at their surfaces, (3) displayed a faster apparent rate of LDL internalization and delivery to lysosomes, and (4) contained more gold-labeled lysosomes. Data from biochemical studies in which 125 I-LDL was used supported the morphological findings. In conclusion, this study demonstrates that FSH has important effects at the cellular level on LDL uptake, which seem to underlie the striking increase in progestin production accompanying granulosa cell differentiation

What are lipoproteins doing in the brain?

Science.gov (United States)

Wang, Hong; Eckel, Robert H

2014-01-01

Lipoproteins in plasma transport lipids between tissues, however, only high-density lipoproteins (HDL) appear to traverse the blood-brain barrier (BBB); thus, lipoproteins found in the brain must be produced within the central nervous system. Apolipoproteins E (ApoE) and ApoJ are the most abundant apolipoproteins in the brain, are mostly synthesized by astrocytes, and are found on HDL. In the hippocampus and other brain regions, lipoproteins help to regulate neurobehavioral functions by processes that are lipoprotein receptor-mediated. Moreover, lipoproteins and their receptors also have roles in the regulation of body weight and energy balance, acting through lipoprotein lipase (LPL) and the low-density lipoprotein (LDL) receptor-related protein (LRP). Thus, understanding lipoproteins and their metabolism in the brain provides a new opportunity with potential therapeutic relevance. Copyright © 2013 Elsevier Ltd. All rights reserved.

Metabolism of lipoproteins by human fetal hepatocytes

International Nuclear Information System (INIS)

Carr, B.R.

1987-01-01

The rate of clearance of lipoproteins from plasma appears to play a role in the development of atherogenesis. The liver may account for as much as two thirds of the removal of low-density lipoprotein and one third of the clearance of high-density lipoprotein in certain animal species and humans, mainly by receptor-mediated pathways. The purpose of the present investigation was to determine if human fetal hepatocytes maintained in vitro take up and degrade lipoproteins. We first determined that the maximal binding capacity of iodine 125-iodo-LDL was approximately 300 ng of low-density lipoprotein protein/mg of membrane protein and an apparent dissociation constant of approximately 60 micrograms low-density lipoprotein protein/ml in membranes prepared from human fetal liver. We found that the maximal uptake of [ 125 I]iodo-LDL and [ 125 I]iodo-HDL by fetal hepatocytes occurred after 12 hours of incubation. Low-density lipoprotein uptake preceded the appearance of degradation products by 4 hours, and thereafter the degradation of low-density lipoprotein increased linearly for at least 24 hours. In contrast, high-density lipoprotein was not degraded to any extent by fetal hepatocytes. [ 125 I]Iodo-LDL uptake and degradation were inhibited more than 75% by preincubation with low-density lipoprotein but not significantly by high-density lipoprotein, whereas [ 125 I]iodo-HDL uptake was inhibited 70% by preincubation with high-density lipoprotein but not by low-density lipoprotein. In summary, human fetal hepatocytes take up and degrade low-density lipoprotein by a receptor-mediated process similar to that described for human extrahepatic tissues

Spirochetal Lipoproteins and Immune Evasion

Science.gov (United States)

Christodoulides, Alexei; Boyadjian, Ani; Kelesidis, Theodoros

2017-01-01

Spirochetes are a major threat to public health. However, the exact pathogenesis of spirochetal diseases remains unclear. Spirochetes express lipoproteins that often determine the cross talk between the host and spirochetes. Lipoproteins are pro-inflammatory, modulatory of immune responses, and enable the spirochetes to evade the immune system. In this article, we review the modulatory effects of spirochetal lipoproteins related to immune evasion. Understanding lipoprotein-induced immunomodulation will aid in elucidating innate pathogenesis processes and subsequent adaptive mechanisms potentially relevant to spirochetal disease vaccine development and treatment. PMID:28424696

Release of endothelial cell lipoprotein lipase by plasma lipoproteins and free fatty acids

International Nuclear Information System (INIS)

Saxena, U.; Witte, L.D.; Goldberg, I.J.

1989-01-01

Lipoprotein lipase (LPL) bound to the lumenal surface of vascular endothelial cells is responsible for the hydrolysis of triglycerides in plasma lipoproteins. Studies were performed to investigate whether human plasma lipoproteins and/or free fatty acids would release LPL which was bound to endothelial cells. Purified bovine milk LPL was incubated with cultured porcine aortic endothelial cells resulting in the association of enzyme activity with the cells. When the cells were then incubated with media containing chylomicrons or very low density lipoproteins (VLDL), a concentration-dependent decrease in the cell-associated LPL enzymatic activity was observed. In contrast, incubation with media containing low density lipoproteins or high density lipoproteins produced a much smaller decrease in the cell-associated enzymatic activity. The addition of increasing molar ratios of oleic acid:bovine serum albumin to the media also reduced enzyme activity associated with the endothelial cells. To determine whether the decrease in LPL activity was due to release of the enzyme from the cells or inactivation of the enzyme, studies were performed utilizing radioiodinated bovine LPL. Radiolabeled LPL protein was released from endothelial cells by chylomicrons, VLDL, and by free fatty acids (i.e. oleic acid bound to bovine serum albumin). The release of radiolabeled LPL by VLDL correlated with the generation of free fatty acids from the hydrolysis of VLDL triglyceride by LPL bound to the cells. Inhibition of LPL enzymatic activity by use of a specific monoclonal antibody, reduced the extent of release of 125 I-LPL from the endothelial cells by the added VLDL. These results demonstrated that LPL enzymatic activity and protein were removed from endothelial cells by triglyceride-rich lipoproteins (chylomicrons and VLDL) and oleic acid

Radiolabelled lipoproteins and method for making same

International Nuclear Information System (INIS)

Lees, R.S.

1987-01-01

A method is described for detecting accumulation of low density lipoproteins in an arterial wall, the method comprising the steps of A. preparing a technetium-99m-labelled low density lipoprotein in a solution having a pH between 8 and 9; B. injecting the labelled low density lipoprotein into the vascular system of a patient; C. subsequently viewing the patient's vascular system with extracorporeally-located detecting means capable of detecting the labelled low density lipoprotein; D. determining from the detecting means the locations of the labelled density lipoproteins; and E. quantifying concentrations of the labelled low density lipoproteins at the locations to determine the accumulation of the lipoproteins

Pharmacologic management of isolated low high-density lipoprotein syndrome.

Science.gov (United States)

Bermúdez, Valmore; Cano, Raquel; Cano, Clímaco; Bermúdez, Fernando; Arraiz, Nailet; Acosta, Luis; Finol, Freddy; Pabón, María Rebeca; Amell, Anilsa; Reyna, Nadia; Hidalgo, Joaquin; Kendall, Paúl; Manuel, Velasco; Hernández, Rafael

2008-01-01

High-density lipoprotein (HDL) cholesterol is a heterogeneous group of lipoproteins exhibiting a variety of properties like prostacyclin production stimulation, decrease in platelet aggregation, endothelial cell apoptosis inhibition, and low-density lipoprotein oxidation blockade. Epidemiologic studies have shown an inverse relation between HDL cholesterol levels and cardiovascular risk. Low HDL cholesterol is associated with increased risk for myocardial infarction, stroke, sudden death, peripheral artery disease, and postangioplasty restenosis. In contrast, high HDL levels are associated with longevity and protection against atherosclerotic disease development. Given the evolving epidemic of obesity, diabetes mellitus, and metabolic syndrome, the prevalence of low HDL will continue to rise. In the United States, low HDL is present in 35% of men, 15% of women, and approximately 63% of patients with coronary artery disease. Data extracted from the Framingham study highlight that 1-mg increase in HDL levels decreases by 2% to 3% the risk of cardiovascular disease. There is no doubt regarding clinical importance about isolated low HDL, but relatively few clinicians consider a direct therapeutic intervention of this dyslipidemia. In this sense, lifestyle measures should be the first-line strategy to manage low HDL levels. On the other hand, pharmacologic options include niacin, fibrates, and statins. Fibrates appear to reduce risk preferentially in patients with low HDL with metabolic syndrome, whereas statins reduce risk across all levels of HDL. Torcetrapib, a cholesteryl esters transfer protein inhibitor, represented a hope to raise this lipoprotein; however, all clinical trials on this drug had ceased after ILLUMINATE, RADIANCE and ERASE trials had recorded an increase in mortality, rates of myocardial infarction, angina, and heart failure. In the near future, drugs as beta-glucans, Apo-A1 mimetic peptides, and ACAT inhibitors, are the new promises to treat this

Familial lipoprotein lipase deficiency

Science.gov (United States)

... lack an enzyme called lipoprotein lipase. Without this enzyme, the body cannot break down fat from digested food. Fat particles called chylomicrons build up in the blood. Risk factors include a family history of lipoprotein lipase deficiency. The condition is usually ...

Synthetic Lipoproteins as Carriers for Drug Delivery.

Science.gov (United States)

Huang, Gangliang; Liu, Yang; Huang, Hualiang

2016-01-01

Synthetic lipoprotein is an effective carrier of targeted delivery for drugs. It has the very small size, good biocompatibility, suitable half-life, and specific lipoprotein receptorbinding capacity. Compared with the traditional natural lipoprotein, synthetic lipoprotein not only retains the original biological characteristics and functions, but also exhibits the excellent characteristics in drug delivery. Herein, the advantages, development, applications, and prospect of synthetic lipoproteins as drug carriers were summarized.

Remnant lipoproteins.

Science.gov (United States)

Varbo, Anette; Nordestgaard, Børge G

2017-08-01

To review recent advances in the field of remnant lipoproteins and remnant cholesterol with a focus on cardiovascular disease risk. In line with previous years' research, current observational, genetic, and mechanistic studies find remnant lipoproteins (defined in different ways) to be involved in atherosclerosis development and cardiovascular disease risk. High concentrations of remnant cholesterol could explain some of the residual risk of cardiovascular disease seen after LDL cholesterol lowering. This will be increasingly important as populations worldwide become more obese and more have diabetes, both of which elevate remnant cholesterol concentrations. Many smaller scale studies and post hoc analyses show that remnant cholesterol can be lowered by different types of drugs; however, results from large scale studies with the primary aim of reducing cardiovascular disease risk through lowering of remnant cholesterol in individuals with elevated concentrations are still missing, although some are under way. Remnant cholesterol is a risk factor for cardiovascular disease, and can be lowered by different types of drugs; however, large scale studies of cardiovascular disease risk reduction through remnant lipoprotein lowering are under way.

Genetics of non-conventional lipoprotein fractions

Science.gov (United States)

Lipoprotein subclass measures associate with cardiometabolic disease risk. Currently the information that lipoproteins convey on disease risk over that of traditional demographic and lipid measures is minimal, and so their use is clinics is limited. However, lipoprotein subclass perturbations repres...

Effects of hormones on lipids and lipoproteins

Energy Technology Data Exchange (ETDEWEB)

Krauss, R.M.

1991-12-01

Levels of plasma lipids and lipoproteins are strong predictors for the development of atherosclerotic cardiovascular disease in postmenopausal women. In women, as in men, numerous factors contribute to variations in plasma lipoproteins that may affect cardiovascular disease risk. These include age, dietary components, adiposity, genetic traits, and hormonal changes. Each of these factors may operate to varying degrees in determining changes in plasma lipoprotein profiles accompanying menopause- Cross-sectional and longitudinal studies have suggested increases in levels of cholesterol, low density lipoproteins (LDL) and triglyceride-rich lipoproteins associated with menopause. High density lipoproteins (HDL), which are higher in women than men and are thought to contribute to relative protection of premenopausal women from cardiovascular disease, remain relatively constant in the years following menopause, although small, and perhaps transient reductions in the HDL{sub 2} subfraction have been reported in relation to reduced estradiol level following menopause. Despite these associations, it has been difficult to determine the role of endogenous hormones in influencing the plasma lipoproteins of postmenopausal women. In principle, the effects of hormone replacement should act to reverse any alterations in lipoprotein metabolism that are due to postmenopausal hormone changes. While there may be beneficial effects on lipoproteins, hormone treatment does not restore a premenopausal lipoprotein profile. Furthermore, it is not dear to what extent exogenous hormone-induced lipoprotein changes contribute to the reduced incidence of cardiovascular disease with hormone replacement therapy.

Revisiting the gram-negative lipoprotein paradigm

Science.gov (United States)

The processing of lipoproteins (lpps) in Gram-negative bacteria is generally considered to be an essential pathway. Mature lipoproteins in these bacteria are triacylated, with the final fatty acid addition performed by Lnt, an apolipoprotein n-acyltransferase. The mature lipoproteins are then sorted...

Lutzomyia sand fly diversity and rates of infection by Wolbachia and an exotic Leishmania species on Barro Colorado Island, Panama.

Directory of Open Access Journals (Sweden)

Jorge Azpurua

2010-03-01

Full Text Available Sand flies (Diptera, Psychodidae, Phlebotominae in the genus Lutzomyia are the predominant vectors of the protozoan disease leishmaniasis in the New World. Within the watershed of the Panama Canal, the cutaneous form of leishmaniasis is a continuous health threat for residents, tourists and members of an international research community. Here we report the results of screening a tropical forest assemblage of sand fly species for infection by both Leishmania and a microbe that can potentially serve in vector population control, the cytoplasmically transmitted rickettsia, Wolbachia pipientis. Knowing accurately which Lutzomyia species are present, what their evolutionary relationships are, and how they are infected by strains of both Leishmania and Wolbachia is of critical value for building strategies to mitigate the impact of this disease in humans.We collected, sorted and then used DNA sequences to determine the diversity and probable phylogenetic relationships of the Phlebotominae occurring in the understory of Barro Colorado Island in the Republic of Panama. Sequence from CO1, the DNA barcoding gene, supported 18 morphology-based species determinations while revealing the presence of two possible "cryptic" species, one (Lu. sp. nr vespertilionis within the Vespertilionis group, the other (Lu. gomezi within the Lutzomyia-cruciata series. Using ITS-1 and "minicircle" primers we detected Leishmania DNA in 43.3% of Lu. trapidoi, 26.3% of Lu. gomezi individuals and in 0% of the other 18 sand fly species. Identical ITS-1 sequence was obtained from the Leishmania infecting Lu. trapidoi and Lu. gomezi, sequence which was 93% similar to Leishmania (viannia naiffi in GenBank, a species previously unknown in Panama, but recognized as a type of cutaneous leishmaniasis vectored broadly across northern and central South America. Distinct strains of the intracellular bacterium Wolbachia were detected in three of 20 sand fly species, including Lu. trapidoi

The impact of temperature and Wolbachia infection on vector competence of potential dengue vectors Aedes aegypti and Aedes albopictus in the transmission of dengue virus serotype 1 in southern Taiwan.

Science.gov (United States)

Tsai, Cheng-Hui; Chen, Tien-Huang; Lin, Cheo; Shu, Pei-Yun; Su, Chien-Ling; Teng, Hwa-Jen

2017-11-07

We evaluated the impact of temperature and Wolbachia infection on vector competence of the local Aedes aegypti and Ae. albopictus populations of southern Taiwan in the laboratory. After oral infection with dengue serotype 1 virus (DENV-1), female mosquitoes were incubated at temperatures of 10, 16, 22, 28 and 34 °C. Subsequently, salivary gland, head, and thorax-abdomen samples were analyzed for their virus titer at 0, 5, 10, 15, 20, 25 and 30 days post-infection (dpi) by real-time RT-PCR. The results showed that Ae. aegypti survived significantly longer and that dengue viral genome levels in the thorax-abdomen (10 3.25 ± 0.53 -10 4.09 ± 0.71 PFU equivalents/ml) and salivary gland samples (10 2.67 ± 0.33 -10 3.89 ± 0.58 PFU equivalents/ml) were significantly higher at high temperature (28-34 °C). The survival of Ae. albopictus was significantly better at 16 or 28 °C, but the virus titers from thorax-abdomen (10 0.70 -10 2.39 ± 1.31 PFU equivalents/ml) and salivary gland samples (10 0.12 ± 0.05 -10 1.51 ± 0.31 PFU equivalents/ml) were significantly higher at 22-28 °C. Within viable temperature ranges, the viruses were detectable after 10 dpi in salivary glands and head tissues in Ae. aegypti and after 5-10 dpi in Ae. albopictus. Vector competence was measured in Ae. albopictus with and without Wolbachia at 28 °C. Wolbachia-infected mosquitoes survived significantly better and carried lower virus titers than Wolbachia-free mosquitoes. Wolbachia coinfections (92.8-97.2%) with wAlbA and wAlbB strains were commonly found in a wild population of Ae. albopictus. In southern Taiwan, Ae. aegypti is the main vector of dengue and Ae. albopictus has a non-significant role in the transmission of dengue virus due to the high prevalence of Wolbachia infection in the local mosquito population of southern Taiwan.

Classifying lipoproteins based on their polar profiles.

Science.gov (United States)

Polanco, Carlos; Castañón-González, Jorge Alberto; Buhse, Thomas; Uversky, Vladimir N; Amkie, Rafael Zonana

2016-01-01

The lipoproteins are an important group of cargo proteins known for their unique capability to transport lipids. By applying the Polarity index algorithm, which has a metric that only considers the polar profile of the linear sequences of the lipoprotein group, we obtained an analytical and structural differentiation of all the lipoproteins found in UniProt Database. Also, the functional groups of lipoproteins, and particularly of the set of lipoproteins relevant to atherosclerosis, were analyzed with the same method to reveal their structural preference, and the results of Polarity index analysis were verified by an alternate test, the Cumulative Distribution Function algorithm, applied to the same groups of lipoproteins.

Genetic determinants of LDL, lipoprotein(a), triglyceride-rich lipoproteins and HDL: concordance and discordance with cardiovascular disease risk

DEFF Research Database (Denmark)

Nordestgaard, Børge G; Tybjærg-Hansen, Anne

2011-01-01

To evaluate whether new and known genetic determinants of plasma levels of LDL cholesterol, lipoprotein(a), triglyceride-rich lipoproteins, and HDL cholesterol associate with the risk of cardiovascular disease expected from the effect on lipoprotein levels. Concordance or discordance...... of such genetic determinants with cardiovascular disease risk will either favor or disfavor that these lipoproteins are causally related to cardiovascular disease....

Stimulation of mast cells leads to cholesterol accumulation in macrophages in vitro by a mast cell granule-mediated uptake of low density lipoprotein

International Nuclear Information System (INIS)

Kokkonen, J.O.; Kovanen, P.T.

1987-01-01

The uptake of low density lipoprotein (LDL) by cultured mouse macrophages was markedly promoted by isolated rat mast cell granules present in the culture medium. The granule-mediated uptake of 125 I-LDL enhanced the rate of cholesteryl ester synthesis in the macrophages, the result being accumulation of cholesteryl esters in these cells. Binding of LDL to the granules was essential for the granule-mediated uptake of LDL by macrophages, for the uptake process was prevented by treating the granules with avidin or protamine chloride or by treating LDL with 1,2-cyclohexanedione, all of which inhibit the binding of LDL to the granules. Inhibition of granule phagocytosis by the macrophages with cytochalasin B also abolished the granule-mediated uptake of LDL. Finally, mouse macrophage monolayers and LDL were incubated in the presence of isolated rat serosal mast cells. Stimulation of the mast cells with compound 48/80, a degranulating agent, resulted in dose-dependent release of secretory granules from the mast cells and a parallel increase in 14 C cholesteryl ester synthesis in the macrophages. The results show that, in this in vitro model, the sequence of events leading to accumulation of cholesteryl esters in macrophages involves initial stimulation of mast cells, subsequent release of their secretory granules, binding of LDL to the exocytosed granules, and, finally, phagocytosis of the LDL-containing granules by macrophages

The impact of Wolbachia, male age and mating history on cytoplasmic incompatibility and sperm transfer in Drosophila simulans.

Science.gov (United States)

Awrahman, Z A; Champion de Crespigny, F; Wedell, N

2014-01-01

Most insects harbour a variety of maternally inherited endosymbionts, the most widespread being Wolbachia pipientis that commonly induce cytoplasmic incompatibility (CI) and reduced hatching success in crosses between infected males and uninfected females. High temperature and increasing male age are known to reduce the level of CI in a variety of insects. In Drosophila simulans, infected males have been shown to mate at a higher rate than uninfected males. By examining the impact of mating rate independent of age, this study investigates whether a high mating rate confers an advantage to infected males through restoring their compatibility with uninfected females over and above the effect of age. The impact of Wolbachia infection, male mating rate and age on the number of sperm transferred to females during copulation and how it relates to CI expression was also assessed. As predicted, we found that reproductive compatibility was restored faster in males that mate at higher rate than that of low mating and virgin males, and that the effect of mating history was over and above the effect of male age. Nonvirgin infected males transferred fewer sperm than uninfected males during copulation, and mating at a high rate resulted in the transfer of fewer sperm per mating irrespective of infection status. These results indicate that the advantage to infected males of mating at a high rate is through restoration of reproductive compatibility with uninfected females, whereas uninfected males appear to trade off the number of sperm transferred per mating with female encounter rate and success in sperm competition. This study highlights the importance Wolbachia may play in sexual selection by affecting male reproductive strategies. © 2013 The Authors. Journal of Evolutionary Biology © 2013 European Society For Evolutionary Biology.

The role of lipolysis stimulated lipoprotein receptor in breast cancer and directing breast cancer cell behavior.

Directory of Open Access Journals (Sweden)

Denise K Reaves

Full Text Available The claudin-low molecular subtype of breast cancer is of particular interest for clinically the majority of these tumors are poor prognosis, triple negative, invasive ductal carcinomas. Claudin-low tumors are characterized by cancer stem cell-like features and low expression of cell junction and adhesion proteins. Herein, we sought to define the role of lipolysis stimulated lipoprotein receptor (LSR in breast cancer and cancer cell behavior as LSR was recently correlated with tumor-initiating features. We show that LSR was expressed in epithelium, endothelium, and stromal cells within the healthy breast tissue, as well as in tumor epithelium. In primary breast tumor bioposies, LSR expression was significantly correlated with invasive ductal carcinomas compared to invasive lobular carcinomas, as well as ERα positive tumors and breast cancer cell lines. LSR levels were significantly reduced in claudin-low breast cancer cell lines and functional studies illustrated that re-introduction of LSR into a claudin-low cell line suppressed the EMT phenotype and reduced individual cell migration. However, our data suggest that LSR may promote collective cell migration. Re-introduction of LSR in claudin-low breast cancer cell lines reestablished tight junction protein expression and correlated with transepithelial electrical resistance, thereby reverting claudin-low lines to other intrinsic molecular subtypes. Moreover, overexpression of LSR altered gene expression of pathways involved in transformation and tumorigenesis as well as enhanced proliferation and survival in anchorage independent conditions, highlighting that reestablishment of LSR signaling promotes aggressive/tumor initiating cell behaviors. Collectively, these data highlight a direct role for LSR in driving aggressive breast cancer behavior.

Increased cell motility and invasion upon knockdown of lipolysis stimulated lipoprotein receptor (LSR in SW780 bladder cancer cells

Directory of Open Access Journals (Sweden)

Ørntoft Torben F

2008-07-01

Full Text Available Abstract Background Mechanisms underlying the malignant development in bladder cancer are still not well understood. Lipolysis stimulated lipoprotein receptor (LSR has previously been found to be upregulated by P53. Furthermore, we have previously found LSR to be differentially expressed in bladder cancer. Here we investigated the role of LSR in bladder cancer. Methods A time course siRNA knock down experiment was performed to investigate the functional role of LSR in SW780 bladder cancer cells. Since LSR was previously shown to be regulated by P53, siRNA against TP53 was included in the experimental setup. We used Affymetrix GeneChips for measuring gene expression changes and we used Ingenuity Pathway Analysis to investigate the relationship among differentially expressed genes upon siRNA knockdown. Results By Ingenuity Pathway analysis of the microarray data from the different timepoints we identified six gene networks containing genes mainly related to the functional categories "cancer", "cell death", and "cellular movement". We determined that genes annotated to the functional category "cellular movement" including "invasion" and "cell motility" were highly significantly overrepresented. A matrigel assay showed that 24 h after transfection the invasion capacity was significantly increased 3-fold (p Conclusion We conclude that LSR may impair bladder cancer cells from gaining invasive properties.

Lipoprotein metabolism indicators improve cardiovascular risk prediction.

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Daniël B van Schalkwijk

Full Text Available BACKGROUND: Cardiovascular disease risk increases when lipoprotein metabolism is dysfunctional. We have developed a computational model able to derive indicators of lipoprotein production, lipolysis, and uptake processes from a single lipoprotein profile measurement. This is the first study to investigate whether lipoprotein metabolism indicators can improve cardiovascular risk prediction and therapy management. METHODS AND RESULTS: We calculated lipoprotein metabolism indicators for 1981 subjects (145 cases, 1836 controls from the Framingham Heart Study offspring cohort in which NMR lipoprotein profiles were measured. We applied a statistical learning algorithm using a support vector machine to select conventional risk factors and lipoprotein metabolism indicators that contributed to predicting risk for general cardiovascular disease. Risk prediction was quantified by the change in the Area-Under-the-ROC-Curve (ΔAUC and by risk reclassification (Net Reclassification Improvement (NRI and Integrated Discrimination Improvement (IDI. Two VLDL lipoprotein metabolism indicators (VLDLE and VLDLH improved cardiovascular risk prediction. We added these indicators to a multivariate model with the best performing conventional risk markers. Our method significantly improved both CVD prediction and risk reclassification. CONCLUSIONS: Two calculated VLDL metabolism indicators significantly improved cardiovascular risk prediction. These indicators may help to reduce prescription of unnecessary cholesterol-lowering medication, reducing costs and possible side-effects. For clinical application, further validation is required.

Bacterial lipoproteins; biogenesis, sorting and quality control.

Science.gov (United States)

Narita, Shin-Ichiro; Tokuda, Hajime

2017-11-01

Bacterial lipoproteins are a subset of membrane proteins localized on either leaflet of the lipid bilayer. These proteins are anchored to membranes through their N-terminal lipid moiety attached to a conserved Cys. Since the protein moiety of most lipoproteins is hydrophilic, they are expected to play various roles in a hydrophilic environment outside the cytoplasmic membrane. Gram-negative bacteria such as Escherichia coli possess an outer membrane, to which most lipoproteins are sorted. The Lol pathway plays a central role in the sorting of lipoproteins to the outer membrane after lipoprotein precursors are processed to mature forms in the cytoplasmic membrane. Most lipoproteins are anchored to the inner leaflet of the outer membrane with their protein moiety in the periplasm. However, recent studies indicated that some lipoproteins further undergo topology change in the outer membrane, and play critical roles in the biogenesis and quality control of the outer membrane. This article is part of a Special Issue entitled: Bacterial Lipids edited by Russell E. Bishop. Copyright © 2016 Elsevier B.V. All rights reserved.

Effect of bicarbonate on iron-mediated oxidation of low-density lipoprotein

Science.gov (United States)

Arai, Hirofumi; Berlett, Barbara S.; Chock, P. Boon; Stadtman, Earl R.

2005-07-01

Oxidation of low-density lipoprotein (LDL) may play an important role in atherosclerosis. We studied the effects of bicarbonate/CO2 and phosphate buffer systems on metal ion-catalyzed oxidation of LDL to malondialdehyde (MDA) and to protein carbonyl and MetO derivatives. Our results revealed that LDL oxidation in mixtures containing free iron or heme derivatives was much greater in bicarbonate/CO2 compared with phosphate buffer. However, when copper was substituted for iron in these mixtures, the rate of LDL oxidation in both buffers was similar. Iron-catalyzed oxidation of LDL was highly sensitive to inhibition by phosphate. Presence of 0.3-0.5 mM phosphate, characteristic of human serum, led to 30-40% inhibition of LDL oxidation in bicarbonate/CO2 buffer. Iron-catalyzed oxidation of LDL to MDA in phosphate buffer was inhibited by increasing concentrations of albumin (10-200 μM), whereas MDA formation in bicarbonate/CO2 buffer was stimulated by 10-50 μM albumin but inhibited by higher concentrations. However, albumin stimulated the oxidation of LDL proteins to carbonyl derivatives at all concentrations examined in both buffers. Conversion of LDL to MDA in bicarbonate/CO2 buffer was greatly stimulated by ADP, ATP, and EDTA but only when EDTA was added at a concentration equal to that of iron. At higher than stoichiometric concentrations, EDTA prevented oxidation of LDL. Results of these studies suggest that interactions between bicarbonate and iron or heme derivatives leads to complexes with redox potentials that favor the generation of reactive oxygen species and/or to the generation of highly reactive CO2 anion or bicarbonate radical that facilitates LDL oxidation. Freely available online through the PNAS open access option.Abbreviations: LDL, low-density lipoprotein; MDA, malondialdehyde; MetO, methionine sulfoxide.

Lipoprotein metabolism indicators improve cardiovascular risk prediction

NARCIS (Netherlands)

Schalkwijk, D.B. van; Graaf, A.A. de; Tsivtsivadze, E.; Parnell, L.D.; Werff-van der Vat, B.J.C. van der; Ommen, B. van; Greef, J. van der; Ordovás, J.M.

2014-01-01

Background: Cardiovascular disease risk increases when lipoprotein metabolism is dysfunctional. We have developed a computational model able to derive indicators of lipoprotein production, lipolysis, and uptake processes from a single lipoprotein profile measurement. This is the first study to

Acute central neuropeptide Y administration increases food intake but does not affect hepatic very low-density lipoprotein (VLDL) production in mice

NARCIS (Netherlands)

Geerling, Janine J.; Wang, Yanan; Havekes, Louis M.; Romijn, Johannes A.; Rensen, Patrick C. N.

2013-01-01

Central neuropeptide Y (NPY) administration stimulates food intake in rodents. In addition, acute modulation of central NPY signaling increases hepatic production of very low-density lipoprotein (VLDL)-triglyceride (TG) in rats. As hypertriglyceridemia is an important risk factor for

Effects of aerobic exercise on lipids and lipoproteins.

Science.gov (United States)

Wang, Yating; Xu, Danyan

2017-07-05

Dyslipidemia is the risk of cardiovascular disease, and their relationship is clear. Lowering serum cholesterol can reduce the risk of coronary heart disease. At present, the main treatment is taking medicine, however, drug treatment has its limitations. Exercise not only has a positive effect on individuals with dyslipidemia, but can also help improve lipids profile. This review is intending to provide information on the effects of exercise training on both tranditional lipids, for example, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, triglycerides and new lipids and lipoproteins such as non-high-density lipoprotein cholesterol, and postprandial lipoprotein. The mechanisms of aerobic exercise on lipids and lipoproteins are also briefly described.

Acute Central Neuropeptide Y Administration Increases Food Intake but Does Not Affect Hepatic Very Low-Density Lipoprotein (Vldl) Production in Mice

NARCIS (Netherlands)

Geerling, J.J.; Wang, Y.; Havekes, L.M.; Romijn, J.A.; Rensen, P.C.N.

2013-01-01

Objective: Central neuropeptide Y (NPY) administration stimulates food intake in rodents. In addition, acute modulation of central NPY signaling increases hepatic production of very low-density lipoprotein (VLDL)-triglyceride (TG) in rats. As hypertriglyceridemia is an important risk factor for

Transfer of plasma lipoprotein components and of plasma proteins into aortas of cholesterol-fed rabbits. Molecular size as a determinant of plasma lipoprotein influx

International Nuclear Information System (INIS)

Stender, S.; Zilversmit, D.B.

1981-01-01

The arterial influx of esterified and free cholesterol from low density lipoproteins and very low density lipoproteins in 20 hypercholesterolemic rabbits was measured simultaneously by the use of lipoproteins labeled in vivo with [ 3 H]- and [ 14 C]-cholesterol. The simultaneous arterial influx of either [ 3 H]-leucine-labeled very low density lipoproteins, low density lipoproteins, high density lipoproteins, or plasma proteins was also measured in each rabbit. The arterial influx was calculated as intimal clearance, i.e., the influx of a given fraction divided by its plasma concentration. The intimal clearance of low density lipoprotein esterified cholesterol was equal to that for the apolipoproteins of that fraction, which is compatible with an arterial influx of intact low density lipoprotein molecules. The intimal clearance of very low density apolipoprotein or cholesteryl ester was less than that for low density lipoprotein, whereas high density lipoprotein and albumin clearances exceeded low density lipoprotein clearance by 1.5- to 3-fold. The intimal clearances of plasma proteins, high density, low density, and very low density lipoproteins decreased linearly with the logarithm of the macromolecular diameter. This indicates that the arterial influx of three plasma lipoprotein fractions and of plasma proteins proceeds by similar mechanisms. Apparently the relative intimal clearances of lipoproteins are more dependent on their size relative to pores or vesicular diameters at the plasma-artery interface than on specific interactions between lipoproteins and the arterial intimal surface

Lipoprotein particle distribution and skeletal muscle lipoprotein lipase activity after acute exercise.

Science.gov (United States)

Harrison, Michael; Moyna, Niall M; Zderic, Theodore W; O'Gorman, Donal J; McCaffrey, Noel; Carson, Brian P; Hamilton, Marc T

2012-07-10

Many of the metabolic effects of exercise are due to the most recent exercise session. With recent advances in nuclear magnetic resonance spectroscopy (NMRS), it is possible to gain insight about which lipoprotein particles are responsible for mediating exercise effects. Using a randomized cross-over design, very low density lipoprotein (VLDL) responses were evaluated in eight men on the morning after i) an inactive control trial (CON), ii) exercising vigorously on the prior evening for 100 min followed by fasting overnight to maintain an energy and carbohydrate deficit (EX-DEF), and iii) after the same exercise session followed by carbohydrate intake to restore muscle glycogen and carbohydrate balance (EX-BAL). The intermediate, low and high density lipoprotein particle concentrations did not differ between trials. Fasting triglyceride (TG) determined biochemically, and mean VLDL size were lower in EX-DEF but not in EX-BAL compared to CON, primarily due to a reduction in VLDL-TG in the 70-120 nm (large) particle range. In contrast, VLDL-TG was lower in both EX-DEF and EX-BAL compared to CON in the 43-55 nm (medium) particle range. VLDL-TG in smaller particles (29-43 nm) was unaffected by exercise. Because the majority of VLDL particles were in this smallest size range and resistant to change, total VLDL particle concentration was not different between any of these conditions. Skeletal muscle lipoprotein lipase (LPL) activity was also not different across these 3 trials. However, in CON only, the inter-individual differences in LPL activity were inversely correlated with fasting TG, VLDL-TG, total, large and small VLDL particle concentration and VLDL size, indicating a regulatory role for LPL in the non-exercised state. These findings reveal a high level of differential regulation between different sized triglyceride-rich lipoproteins following exercise and feeding, in the absence of changes in LPL activity.

A Phospholipidomic Analysis of All Defined Human Plasma Lipoproteins

Science.gov (United States)

Dashti, Monireh; Kulik, Willem; Hoek, Frans; Veerman, Enno C.; Peppelenbosch, Maikel P.; Rezaee, Farhad

2011-01-01

Since plasma lipoproteins contain both protein and phospholipid components, either may be involved in processes such as atherosclerosis. In this study the identification of plasma lipoprotein-associated phospholipids, which is essential for understanding these processes at the molecular level, are performed. LC-ESI/MS, LC-ESI-MS/MS and High Performance Thin Layer Chromatography (HPTLC) analysis of different lipoprotein fractions collected from pooled plasma revealed the presence of phosphatidylethanolamine (PE), phosphatidylinositol (PI), and sphingomyeline (SM) only on lipoproteins and phosphatidylcholine (PC), Lyso-PC on both lipoproteins and plasma lipoprotein free fraction (PLFF). Cardiolipin, phosphatidylglycerol (PG) and Phosphatidylserine (PS) were observed neither in the lipoprotein fractions nor in PLFF. All three approaches led to the same results regarding phospholipids occurrence in plasma lipoproteins and PLFF. A high abundancy of PE and SM was observed in VLDL and LDL fractions respectively. This study provides for the first time the knowledge about the phospholipid composition of all defined plasma lipoproteins. PMID:22355656

Ultrasound-Stimulated Drug Delivery Using Therapeutic Reconstituted High-Density Lipoprotein Nanoparticles.

Science.gov (United States)

Xiong, Fangyuan; Nirupama, Sabnis; Sirsi, Shashank R; Lacko, Andras; Hoyt, Kenneth

2017-01-01

The abnormal tumor vasculature and the resulting abnormal microenvironment are major barriers to optimal chemotherapeutic drug delivery. It is well known that ultrasound (US) can increase the permeability of the tumor vessel walls and enhance the accumulation of anticancer agents. Reconstituted high-density lipoproteins (rHDL) nanoparticles (NPs) allow selective delivery of anticancer agents to tumor cells via their overexpressed scavenger receptor type B1 (SR-B1) receptor. The goal of this study is to investigate the potential of noninvasive US therapy to further improve delivery and tumor uptake of the payload from rHDL NPs, preloaded with an infrared dye (IR-780), aimed to establish a surrogate chemotherapeutic model with optical localization. Athymic nude mice were implanted orthotopically with one million breast cancer cells (MDA-MB-231/Luc). Three weeks later, animals were divided into seven groups with comparable mean tumor size: control, low, moderate, and high concentration of rHDL NPs alone groups, as well as these three levels of rHDL NPs plus US therapy groups ( N = 7 to 12 animals per group), where low, moderate and high denote 5, 10, and 50 µg of the IR-780 dye payload per rHDL NP injection, respectively. The US therapy system included a single element focused transducer connected in series with a function generator and power amplifier. A custom 3D printed cone with an acoustically transparent aperture and filled with degassed water allowed delivery of focused US energy to the tumor tissue. US exposure involved a pulsed sequence applied for a duration of 5 min. Each animal in the US therapy groups received a slow bolus co-injection of MB contrast agent and rHDL NPs. Animals were imaged using a whole-body optical system to quantify intratumoral rHDL NP accumulation at baseline and again at 1 min, 30 min, 24 h, and 48 h. At 48 h, all animals were euthanized and tumors were excised for ex vivo analysis. We investigated a noninvasive optical imaging

Aminoacylation of the N-terminal cysteine is essential for Lol-dependent release of lipoproteins from membranes but does not depend on lipoprotein sorting signals.

Science.gov (United States)

Fukuda, Ayumu; Matsuyama, Shin-Ichi; Hara, Takashi; Nakayama, Jiro; Nagasawa, Hiromichi; Tokuda, Hajime

2002-11-08

Lipoproteins are present in a wide variety of bacteria and are anchored to membranes through lipids attached to the N-terminal cysteine. The Lol system of Escherichia coli mediates the membrane-specific localization of lipoproteins. Aspartate at position 2 functions as a Lol avoidance signal and causes the retention of lipoproteins in the inner membrane, whereas lipoproteins having residues other than aspartate at position 2 are released from the inner membrane and localized to the outer membrane by the Lol system. Phospholipid:apolipoprotein transacylase, Lnt, catalyzes the last step of lipoprotein modification, converting apolipoprotein into mature lipoprotein. To reveal the importance of this aminoacylation for the Lol-dependent membrane localization, apolipoproteins were prepared by inhibiting lipoprotein maturation. Lnt was also purified and used to convert apolipoprotein into mature lipoprotein in vitro. The release of these lipoproteins was examined in proteoliposomes. We show here that the aminoacylation is essential for the Lol-dependent release of lipoproteins from membranes. Furthermore, lipoproteins with aspartate at position 2 were found to be aminoacylated both in vivo and in vitro, indicating that the lipoprotein-sorting signal does not affect lipid modification.

A More Flexible Lipoprotein Sorting Pathway

Science.gov (United States)

Chahales, Peter

2015-01-01

Lipoprotein biogenesis in Gram-negative bacteria occurs by a conserved pathway, each step of which is considered essential. In contrast to this model, LoVullo and colleagues demonstrate that the N-acyl transferase Lnt is not required in Francisella tularensis or Neisseria gonorrhoeae. This suggests the existence of a more flexible lipoprotein pathway, likely due to a modified Lol transporter complex, and raises the possibility that pathogens may regulate lipoprotein processing to modulate interactions with the host. PMID:25755190

Analyzing the molecular mechanism of lipoprotein localization in Brucella.

Science.gov (United States)

Goolab, Shivani; Roth, Robyn L; van Heerden, Henriette; Crampton, Michael C

2015-01-01

Bacterial lipoproteins possess diverse structure and functionality, ranging from bacterial physiology to pathogenic processes. As such many lipoproteins, originating from Brucella are exploited as potential vaccines to countermeasure brucellosis infection in the host. These membrane proteins are translocated from the cytoplasm to the cell membrane where they are anchored peripherally by a multifaceted targeting mechanism. Although much research has focused on the identification and classification of Brucella lipoproteins and their potential use as vaccine candidates for the treatment of Brucellosis, the underlying route for the translocation of these lipoproteins to the outer surface of the Brucella (and other pathogens) outer membrane (OM) remains mostly unknown. This is partly due to the complexity of the organism and evasive tactics used to escape the host immune system, the variation in biological structure and activity of lipoproteins, combined with the complex nature of the translocation machinery. The biosynthetic pathway of Brucella lipoproteins involves a distinct secretion system aiding translocation from the cytoplasm, where they are modified by lipidation, sorted by the lipoprotein localization machinery pathway and thereafter equipped for export to the OM. Surface localized lipoproteins in Brucella may employ a lipoprotein flippase or the β-barrel assembly complex for translocation. This review provides an overview of the characterized Brucella OM proteins that form part of the OM, including a handful of other characterized bacterial lipoproteins and their mechanisms of translocation. Lipoprotein localization pathways in gram negative bacteria will be used as a model to identify gaps in Brucella lipoprotein localization and infer a potential pathway. Of particular interest are the dual topology lipoproteins identified in Escherichia coli and Haemophilus influenza. The localization and topology of these lipoproteins from other gram negative bacteria

Analyzing the molecular mechanism of lipoprotein localization in Brucella

Science.gov (United States)

Goolab, Shivani; Roth, Robyn L.; van Heerden, Henriette; Crampton, Michael C.

2015-01-01

Bacterial lipoproteins possess diverse structure and functionality, ranging from bacterial physiology to pathogenic processes. As such many lipoproteins, originating from Brucella are exploited as potential vaccines to countermeasure brucellosis infection in the host. These membrane proteins are translocated from the cytoplasm to the cell membrane where they are anchored peripherally by a multifaceted targeting mechanism. Although much research has focused on the identification and classification of Brucella lipoproteins and their potential use as vaccine candidates for the treatment of Brucellosis, the underlying route for the translocation of these lipoproteins to the outer surface of the Brucella (and other pathogens) outer membrane (OM) remains mostly unknown. This is partly due to the complexity of the organism and evasive tactics used to escape the host immune system, the variation in biological structure and activity of lipoproteins, combined with the complex nature of the translocation machinery. The biosynthetic pathway of Brucella lipoproteins involves a distinct secretion system aiding translocation from the cytoplasm, where they are modified by lipidation, sorted by the lipoprotein localization machinery pathway and thereafter equipped for export to the OM. Surface localized lipoproteins in Brucella may employ a lipoprotein flippase or the β-barrel assembly complex for translocation. This review provides an overview of the characterized Brucella OM proteins that form part of the OM, including a handful of other characterized bacterial lipoproteins and their mechanisms of translocation. Lipoprotein localization pathways in gram negative bacteria will be used as a model to identify gaps in Brucella lipoprotein localization and infer a potential pathway. Of particular interest are the dual topology lipoproteins identified in Escherichia coli and Haemophilus influenza. The localization and topology of these lipoproteins from other gram negative bacteria

Nuclear magnetic resonance studies of lipoproteins

International Nuclear Information System (INIS)

Hamilton, J.A.; Morrisett, J.D.

1986-01-01

Several nuclei in lipoproteins are magnetically active and are thus potential NMR probes of lipoprotein structure. Table I lists the magnetic isotopes preset in the covalent structures of the molecular constituents of lipoproteins: lipids, proteins, and carbohydrates. Every type of nucleus that is part of the endogenous structure of these molecules has at least one magnetic isotope. Each magnetic nucleus represents an intrinsic and completely nonperturbing probe (when at the natural abundance level) of local molecular motion and magnetic environment. The NMR experiment itself is also nonperturbing and nondestructive. Table I also lists for each nucleus its nuclear spin, its natural isotopic abundance, its sensitivity, and its resonance frequency at two commonly employed magnetic in the low field range (21.14 kG or 2.11 Tesla) and the other in the high field range (47.0 kG or 4.70 Tesla). Of the nuclei listed in Table I, /sup 1/H, /sup 13/C, and /sup 31/P have been the primary ones studied in lipoproteins. The general advantages and disadvantages afforded by these and other nuclei as probes of lipoprotein structure are discussed. /sup 13/C NMR spectroscopy, the method which has had the most extensive application (and probably has the greatest future potential) to lipoproteins, is treated in greatest detail, but many of the principles described apply to other nuclei as well

Activated platelets contribute to oxidized low-density lipoproteins and dysfunctional high-density lipoproteins through a phospholipase A2-dependent mechanism

NARCIS (Netherlands)

Blache, Denis; Gautier, Thomas; Tietge, Uwe J. F.; Lagrost, Laurent

Plasma activity of secretory phospholipase A2 (sPLA2) increases in patients with cardiovascular disease. The present study investigated whether platelet-released sPLA2 induces low-density lipoprotein (LDL) and high-density lipoprotein (HDL) modifications that translate into changes in lipoprotein

Low-density lipoprotein analysis in microchip capillary electrophoresis systems

NARCIS (Netherlands)

Ceriotti, Laura; Shibata, Takayuki; Folmer, Britta; Weiller, Bruce H.; Roberts, Matthew A.; De Rooij, Nico F.; Verpoorte, Elisabeth

2002-01-01

Due to the mounting evidence for altered lipoprotein and cholesterol-lipoprotein content in several disease states, there has been an increasing interest in analytical methods for lipoprotein profiling for diagnosis. The separation of low- and high-density lipoproteins (LDL and HDL, respectively)

Serum and urinary lipoproteins in the human nephrotic syndrome: evidence for renal catabolism of lipoproteins

Energy Technology Data Exchange (ETDEWEB)

Shore, V.G.; Forte, T.; Licht, H.; Lewis, S.B.

1982-03-01

The urinary excretion of lipoproteins and the possibility of catabolic alterations on glomerular filtration were investigated in four nephrotic subjects difering in etiology, serum lipoprotein profile, and 24 hr urinary output of protein and lipids. The apolipoproteins and lipoproteins of urine were compared with those of serum with respect to distribution profile, physical properties, and composition. As expected from molecular sieving effects during glomerular filtration, the urinary HDL were more abundant than the lower density lipoproteins even when the plasma LDL was elevated markedly. Intact apolipoproteins were not found in the concentrated urinary fraction isolated by ultrafiltration between the limits of 10/sup 4/ and 5 x 10/sup 4/ daltons. On the basis of immunoreactivity, gel electrophoresis, and amino acid composition, apolipoproteins B and AI are the major and minor proteins, respectively, of urinary LDL, and apo B is the major protein of the urinary IDL and VLDL. Apolipoproteins AI, AII, CI, CIII, and possibly AIV were isolated from the urinary HDL. As much as 20% of the protein moiety of the urinary HDL appeared to be large apolipoprotien fragments with molecular weights and isoelectric points similar to those of apo CII and apo CIII. The lower density classes of urinary lipoproteins also appeared to have lost apo E and apo C's and to have undergone partial proteolysis.

Lipoprotein-associated phospholipase A2 distribution among lipoproteins differs in type 1 diabetes.

Science.gov (United States)

Jarvie, Jennifer L; Wang, Hong; Kinney, Gregory L; Snell-Bergeon, Janet; Hokanson, John E; Eckel, Robert H

2016-01-01

LpPLA2 mass and activity have been variably related to cardiovascular disease risk, and the distribution of LpPLA2 in patients with type 1 diabetes (T1D), wherein cardiovascular disease risk is high despite normal or higher levels of high-density lipoprotein (HDL) cholesterol, is unknown. To determine whether there are differences in the distribution of LpPLA2 mass and activity across lipoproteins and their association with coronary artery calcium (CAC) in patients with T1D. Men with T1D (n = 19) not on statins, with and without CAC progression, and men without diabetes matched for HDL cholesterol (n = 25) had lipoproteins separated by fast protein liquid chromatography. Both LpPLA2 mass and activity were found within low-density lipoprotein (LDL) and HDL pools with more LpPLA2 mass being associated with HDL (54% vs 44%; P-value lipoprotein subfractions was observed between all groups, and there was no relationship between LpPLA2 activity or mass and its distribution and CAC score progression in healthy or T1D men. LpPLA2 is found in both LDL and HDL and is distributed differently in men with T1D without any relationship to CAC score progression. Copyright © 2016 National Lipid Association. Published by Elsevier Inc. All rights reserved.

Comparison of gemfibrozil versus simvastatin in familial combined hyperlipidemia and effects on apolipoprotein-B-containing lipoproteins, low-density lipoprotein subfraction profile, and low-density lipoprotein oxidizability

NARCIS (Netherlands)

Bredie, S. J.; de Bruin, T. W.; Demacker, P. N.; Kastelein, J. J.; Stalenhoef, A. F.

1995-01-01

We evaluated in a double-blind, placebo-controlled, randomized trial of 45 well-defined patients with familial combined hyperlipidemia, the effect of gemfibrozil (1,200 mg/day) or simvastatin (20 mg/day) on apolipoprotein-B (apo-B)-containing lipoproteins, low-density lipoprotein (LDL) subfraction

A more flexible lipoprotein sorting pathway.

Science.gov (United States)

Chahales, Peter; Thanassi, David G

2015-05-01

Lipoprotein biogenesis in Gram-negative bacteria occurs by a conserved pathway, each step of which is considered essential. In contrast to this model, LoVullo and colleagues demonstrate that the N-acyl transferase Lnt is not required in Francisella tularensis or Neisseria gonorrhoeae. This suggests the existence of a more flexible lipoprotein pathway, likely due to a modified Lol transporter complex, and raises the possibility that pathogens may regulate lipoprotein processing to modulate interactions with the host. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Outer membrane lipoprotein biogenesis: Lol is not the end.

Science.gov (United States)

Konovalova, Anna; Silhavy, Thomas J

2015-10-05

Bacterial lipoproteins are lipid-anchored proteins that contain acyl groups covalently attached to the N-terminal cysteine residue of the mature protein. Lipoproteins are synthesized in precursor form with an N-terminal signal sequence (SS) that targets translocation across the cytoplasmic or inner membrane (IM). Lipid modification and SS processing take place at the periplasmic face of the IM. Outer membrane (OM) lipoproteins take the localization of lipoproteins (Lol) export pathway, which ends with the insertion of the N-terminal lipid moiety into the inner leaflet of the OM. For many lipoproteins, the biogenesis pathway ends here. We provide examples of lipoproteins that adopt complex topologies in the OM that include transmembrane and surface-exposed domains. Biogenesis of such lipoproteins requires additional steps beyond the Lol pathway. In at least one case, lipoprotein sequences reach the cell surface by being threaded through the lumen of a beta-barrel protein in an assembly reaction that requires the heteropentomeric Bam complex. The inability to predict surface exposure reinforces the importance of experimental verification of lipoprotein topology and we will discuss some of the methods used to study OM protein topology. © 2015 The Author(s).

Challenging the Wigglesworthia, Sodalis, Wolbachia symbiosis dogma in tsetse flies: Spiroplasma is present in both laboratory and natural populations.

Science.gov (United States)

Doudoumis, V; Blow, F; Saridaki, A; Augustinos, A; Dyer, N A; Goodhead, I; Solano, P; Rayaisse, J-B; Takac, P; Mekonnen, S; Parker, A G; Abd-Alla, A M M; Darby, A; Bourtzis, K; Tsiamis, G

2017-07-05

Profiling of wild and laboratory tsetse populations using 16S rRNA gene amplicon sequencing allowed us to examine whether the "Wigglesworthia-Sodalis-Wolbachia dogma" operates across species and populations. The most abundant taxa, in wild and laboratory populations, were Wigglesworthia (the primary endosymbiont), Sodalis and Wolbachia as previously characterized. The species richness of the microbiota was greater in wild than laboratory populations. Spiroplasma was identified as a new symbiont exclusively in Glossina fuscipes fuscipes and G. tachinoides, members of the palpalis sub-group, and the infection prevalence in several laboratory and natural populations was surveyed. Multi locus sequencing typing (MLST) analysis identified two strains of tsetse-associated Spiroplasma, present in G. f. fuscipes and G. tachinoides. Spiroplasma density in G. f. fuscipes larva guts was significantly higher than in guts from teneral and 15-day old male and female adults. In gonads of teneral and 15-day old insects, Spiroplasma density was higher in testes than ovaries, and was significantly higher density in live versus prematurely deceased females indicating a potentially mutualistic association. Higher Spiroplasma density in testes than in ovaries was also detected by fluorescent in situ hybridization in G. f. fuscipes.

Lipoprotein particle distribution and skeletal muscle lipoprotein lipase activity after acute exercise

Directory of Open Access Journals (Sweden)

Harrison Michael

2012-07-01

Full Text Available Abstract Background Many of the metabolic effects of exercise are due to the most recent exercise session. With recent advances in nuclear magnetic resonance spectroscopy (NMRS, it is possible to gain insight about which lipoprotein particles are responsible for mediating exercise effects. Methods Using a randomized cross-over design, very low density lipoprotein (VLDL responses were evaluated in eight men on the morning after i an inactive control trial (CON, ii exercising vigorously on the prior evening for 100 min followed by fasting overnight to maintain an energy and carbohydrate deficit (EX-DEF, and iii after the same exercise session followed by carbohydrate intake to restore muscle glycogen and carbohydrate balance (EX-BAL. Results The intermediate, low and high density lipoprotein particle concentrations did not differ between trials. Fasting triglyceride (TG determined biochemically, and mean VLDL size were lower in EX-DEF but not in EX-BAL compared to CON, primarily due to a reduction in VLDL-TG in the 70–120 nm (large particle range. In contrast, VLDL-TG was lower in both EX-DEF and EX-BAL compared to CON in the 43–55 nm (medium particle range. VLDL-TG in smaller particles (29–43 nm was unaffected by exercise. Because the majority of VLDL particles were in this smallest size range and resistant to change, total VLDL particle concentration was not different between any of these conditions. Skeletal muscle lipoprotein lipase (LPL activity was also not different across these 3 trials. However, in CON only, the inter-individual differences in LPL activity were inversely correlated with fasting TG, VLDL-TG, total, large and small VLDL particle concentration and VLDL size, indicating a regulatory role for LPL in the non-exercised state. Conclusions These findings reveal a high level of differential regulation between different sized triglyceride-rich lipoproteins following exercise and feeding, in the absence of changes in

Lipoprotein particle distribution and skeletal muscle lipoprotein lipase activity after acute exercise

LENUS (Irish Health Repository)

Harrison, Michael

2012-06-06

AbstractBackgroundMany of the metabolic effects of exercise are due to the most recent exercise session. With recent advances in nuclear magnetic resonance spectroscopy (NMRS), it is possible to gain insight about which lipoprotein particles are responsible for mediating exercise effects.MethodsUsing a randomized cross-over design, very low density lipoprotein (VLDL) responses were evaluated in eight men on the morning after i) an inactive control trial (CON), ii) exercising vigorously on the prior evening for 100 min followed by fasting overnight to maintain an energy and carbohydrate deficit (EX-DEF), and iii) after the same exercise session followed by carbohydrate intake to restore muscle glycogen and carbohydrate balance (EX-BAL).ResultsThe intermediate, low and high density lipoprotein particle concentrations did not differ between trials. Fasting triglyceride (TG) determined biochemically, and mean VLDL size were lower in EX-DEF but not in EX-BAL compared to CON, primarily due to a reduction in VLDL-TG in the 70–120 nm (large) particle range. In contrast, VLDL-TG was lower in both EX-DEF and EX-BAL compared to CON in the 43–55 nm (medium) particle range. VLDL-TG in smaller particles (29–43 nm) was unaffected by exercise. Because the majority of VLDL particles were in this smallest size range and resistant to change, total VLDL particle concentration was not different between any of these conditions. Skeletal muscle lipoprotein lipase (LPL) activity was also not different across these 3 trials. However, in CON only, the inter-individual differences in LPL activity were inversely correlated with fasting TG, VLDL-TG, total, large and small VLDL particle concentration and VLDL size, indicating a regulatory role for LPL in the non-exercised state.ConclusionsThese findings reveal a high level of differential regulation between different sized triglyceride-rich lipoproteins following exercise and feeding, in the absence of changes in LPL activity.

Challenging the roles of CD44 and lipolysis stimulated lipoprotein receptor in conveying Clostridium perfringens iota toxin cytotoxicity in breast cancer.

Science.gov (United States)

Fagan-Solis, Katerina D; Reaves, Denise K; Rangel, M Cristina; Popoff, Michel R; Stiles, Bradley G; Fleming, Jodie M

2014-07-02

Translational exploration of bacterial toxins has come to the forefront of research given their potential as a chemotherapeutic tool. Studies in select tissues have demonstrated that Clostridium perfringens iota toxin binds to CD44 and lipolysis stimulated lipoprotein receptor (LSR) cell-surface proteins. We recently demonstrated that LSR expression correlates with estrogen receptor positive breast cancers and that LSR signaling directs aggressive, tumor-initiating cell behaviors. Herein, we identify the mechanisms of iota toxin cytotoxicity in a tissue-specific, breast cancer model with the ultimate goal of laying the foundation for using iota toxin as a targeted breast cancer therapy. In vitro model systems were used to determine the cytotoxic effect of iota toxin on breast cancer intrinsic subtypes. The use of overexpression and knockdown technologies confirmed the roles of LSR and CD44 in regulating iota toxin endocytosis and induction of cell death. Lastly, cytotoxicity assays were used to demonstrate the effect of iota toxin on a validated set of tamoxifen resistant breast cancer cell lines. Treatment of 14 breast cancer cell lines revealed that LSR+/CD44- lines were highly sensitive, LSR+/CD44+ lines were slightly sensitive, and LSR-/CD44+ lines were resistant to iota cytotoxicity. Reduction in LSR expression resulted in a significant decrease in toxin sensitivity; however, overexpression of CD44 conveyed toxin resistance. CD44 overexpression was correlated with decreased toxin-stimulated lysosome formation and decreased cytosolic levels of iota toxin. These findings indicated that expression of CD44 drives iota toxin resistance through inhibition of endocytosis in breast cancer cells, a role not previously defined for CD44. Moreover, tamoxifen-resistant breast cancer cells exhibited robust expression of LSR and were highly sensitive to iota-induced cytotoxicity. Collectively, these data are the first to show that iota toxin has the potential to be an

Cholesterol efflux from THP-1 macrophages is impaired by the fatty acid component from lipoprotein hydrolysis by lipoprotein lipase

International Nuclear Information System (INIS)

Yang, Yanbo; Thyagarajan, Narmadaa; Coady, Breanne M.; Brown, Robert J.

2014-01-01

Highlights: • Lipoprotein hydrolysis products were produced by lipoprotein lipase. • Hydrolysis products lowers expression of macrophage cholesterol transporters. • Hydrolysis products reduces expression of select nuclear receptors. • Fatty acid products lowers cholesterol transporters and select nuclear receptors. • Fatty acid products reduces cholesterol efflux from macrophages. - Abstract: Lipoprotein lipase (LPL) is an extracellular lipase that primarily hydrolyzes triglycerides within circulating lipoproteins. Macrophage LPL contributes to atherogenesis, but the mechanisms behind it are poorly understood. We hypothesized that the products of lipoprotein hydrolysis generated by LPL promote atherogenesis by inhibiting the cholesterol efflux ability by macrophages. To test this hypothesis, we treated human THP-1 macrophages with total lipoproteins that were hydrolyzed by LPL and we found significantly reduced transcript levels for the cholesterol transporters ATP binding cassette transporter A1 (ABCA1), ABCG1, and scavenger receptor BI. These decreases were likely due to significant reductions for the nuclear receptors liver-X-receptor-α, peroxisome proliferator activated receptor (PPAR)-α, and PPAR-γ. We prepared a mixture of free fatty acids (FFA) that represented the ratios of FFA species within lipoprotein hydrolysis products, and we found that the FFA mixture also significantly reduced cholesterol transporters and nuclear receptors. Finally, we tested the efflux of cholesterol from THP-1 macrophages to apolipoprotein A-I, and we found that the treatment of THP-1 macrophages with the FFA mixture significantly attenuated cholesterol efflux. Overall, these data show that the FFA component of lipoprotein hydrolysis products generated by LPL may promote atherogenesis by inhibiting cholesterol efflux, which partially explains the pro-atherogenic role of macrophage LPL

Cholesterol efflux from THP-1 macrophages is impaired by the fatty acid component from lipoprotein hydrolysis by lipoprotein lipase

Energy Technology Data Exchange (ETDEWEB)

Yang, Yanbo; Thyagarajan, Narmadaa; Coady, Breanne M.; Brown, Robert J., E-mail: rbrown@mun.ca

2014-09-05

Highlights: • Lipoprotein hydrolysis products were produced by lipoprotein lipase. • Hydrolysis products lowers expression of macrophage cholesterol transporters. • Hydrolysis products reduces expression of select nuclear receptors. • Fatty acid products lowers cholesterol transporters and select nuclear receptors. • Fatty acid products reduces cholesterol efflux from macrophages. - Abstract: Lipoprotein lipase (LPL) is an extracellular lipase that primarily hydrolyzes triglycerides within circulating lipoproteins. Macrophage LPL contributes to atherogenesis, but the mechanisms behind it are poorly understood. We hypothesized that the products of lipoprotein hydrolysis generated by LPL promote atherogenesis by inhibiting the cholesterol efflux ability by macrophages. To test this hypothesis, we treated human THP-1 macrophages with total lipoproteins that were hydrolyzed by LPL and we found significantly reduced transcript levels for the cholesterol transporters ATP binding cassette transporter A1 (ABCA1), ABCG1, and scavenger receptor BI. These decreases were likely due to significant reductions for the nuclear receptors liver-X-receptor-α, peroxisome proliferator activated receptor (PPAR)-α, and PPAR-γ. We prepared a mixture of free fatty acids (FFA) that represented the ratios of FFA species within lipoprotein hydrolysis products, and we found that the FFA mixture also significantly reduced cholesterol transporters and nuclear receptors. Finally, we tested the efflux of cholesterol from THP-1 macrophages to apolipoprotein A-I, and we found that the treatment of THP-1 macrophages with the FFA mixture significantly attenuated cholesterol efflux. Overall, these data show that the FFA component of lipoprotein hydrolysis products generated by LPL may promote atherogenesis by inhibiting cholesterol efflux, which partially explains the pro-atherogenic role of macrophage LPL.

Triglycerides, total cholesterol, high density lipoprotein cholesterol and low density lipoprotein cholesterol in rats exposed to premium motor spirit fumes.

Science.gov (United States)

Aberare, Ogbevire L; Okuonghae, Patrick; Mukoro, Nathaniel; Dirisu, John O; Osazuwa, Favour; Odigie, Elvis; Omoregie, Richard

2011-06-01

Deliberate and regular exposure to premium motor spirit fumes is common and could be a risk factor for liver disease in those who are occupationally exposed. A possible association between premium motor spirit fumes and plasma levels of triglyceride, total cholesterol, high density lipoprotein cholesterol and low density lipoprotein cholesterol using a rodent model could provide new insights in the pathology of diseases where cellular dysfunction is an established risk factor. The aim of this study was to evaluate the possible effect of premium motor spirit fumes on lipids and lipoproteins in workers occupationally exposed to premium motor spirit fumes using rodent model. Twenty-five Wister albino rats (of both sexes) were used for this study between the 4(th) of August and 7(th) of September, 2010. The rats were divided into five groups of five rats each. Group 1 rats were not exposed to premium motor spirit fumes (control group), group 2 rats were exposed for 1 hour daily, group 3 for 3 hours daily, group 4 for 5 hours daily and group 5 for 7 hours daily. The experiment lasted for a period of 4 weeks. Blood samples obtained from all the groups after 4 weeks of exposure were used for the estimation of plasma levels of triglyceride, total cholesterol, high density lipoprotein- cholesterol and low density lipoprotein- cholesterol. Results showed significant increase in means of plasma total cholesterol and low density lipoprotein levels (P<0.05). The mean triglyceride and total body weight were significantly lower (P<0.05) in the exposed group when compared with the unexposed. The plasma level of high density lipoprotein, the ratio of low density lipoprotein to high density lipoprotein and the ratio of total cholesterol to high density lipoprotein did not differ significantly in exposed subjects when compared with the control group. These results showed that frequent exposure to petrol fumes may be highly deleterious to the liver cells.

Transendothelial lipoprotein exchange and microalbuminuria

DEFF Research Database (Denmark)

Jensen, Jan Skov; Feldt-Rasmussen, Bo; Jensen, Kurt Svarre

2004-01-01

OBJECTIVE: Microalbuminuria associates with increased risk of atherosclerosis in individuals without diabetes. We hypothesized that transendothelial lipoprotein exchange is elevated among such individuals, possibly explaining increased intimal lipoprotein accumulation and thus atherosclerosis....... METHODS: Using an in vivo isotope technique, transendothelial exchange of low density lipoprotein (LDL) was measured in 77 non-diabetic individuals. Autologous 131-iodinated LDL was reinjected intravenously, and the 1-h fractional escape rate was calculated as index of transendothelial exchange. RESULTS......: There was no difference in transendothelial LDL exchange between subjects with microalbuminuria versus normoalbuminuria (mean (95% confidence interval) 3.8%/h (3.3-4.3%/h) versus 4.2%/h (3.7-4.7%/h); P=0.33). In contrast, there was a positive correlation between transendothelial LDL exchange and (logarithmically...

Identification of Lipoproteins Using Globomycin and Radioactive Palmitate.

Science.gov (United States)

Buddelmeijer, Nienke

2017-01-01

Bacterial lipoproteins are characterized by fatty acids that are covalently attached to their amino terminus via posttranslational modification in the cytoplasmic membrane. Three enzymatic steps are involved in the synthesis of mature triacylated lipoprotein: prolipoprotein converts into diacylglyceryl-prolipoprotein that in turn converts into apolipoprotein, which is finally converted into mature triacylated lipoprotein. Here we describe the detection of one of these intermediate forms of lipoprotein, diacylglyceryl-prolipoprotein, using 3 H-palmitate labeling and inhibition by globomycin and detection by fluorography.

Hemodynamics alter arterial low-density lipoprotein metabolism

International Nuclear Information System (INIS)

Warty, V.S.; Calvo, W.J.; Berceli, S.A.; Pham, S.M.; Durham, S.J.; Tanksale, S.K.; Klein, E.C.; Herman, I.M.; Borovetz, H.S.

1989-01-01

We have investigated the role of hemodynamic factors on low-density lipoprotein transport and metabolism in the intact arterial wall. Freshly excised canine carotid blood vessels were exposed to well-defined pulsatile flow in vitro for continuous periods up to 20 hours. We chose to impose the following hemodynamic conditions on our test carotid arteries: normotension, hypertension (at physiologic flow conditions), and hypertension coupled with elevated flow of canine serum perfusate. In several experiments the effect of endothelial denudation was examined in carotid arteries exposed to normotensive pulsatile flow. A trapped ligand method was used for quantitating low-density lipoprotein uptake and metabolism in the arterial wall. The distribution of both intact and degraded low-density lipoprotein fractions was determined from measurements of radiolabelled low-density lipoprotein activity within thin radial sections of perfused arteries. Our results suggest that both hypertensive hemodynamic simulations exacerbate the uptake of low-density lipoprotein within the arterial wall (by a factor of three to nine). The percentage of low-density lipoprotein that undergoes irreversible degradation falls from 41% under normotensive conditions to below 30% when hypertensive conditions are imposed, indicating that degradative processes are not proportionally elevated with the accelerated influx. A similar pattern is observed for deendothelialized vessels

High density lipoprotein cholesterol (HDL) metabolism and its role in ischemic heart disease

International Nuclear Information System (INIS)

Pirzado, Z.A.; Sngi, S.A.; Malik, R.

1999-01-01

Case control and prospective epidemiological studies have found a striking, consistently negative association between High Density Lipoprotein(HDL) levels and coronary vascular events. As a results, the genetic and environmental determinants of HDL levels are being studied intensively. These investigations and their potential clinical applications require a fundamental understanding of the structure, function and metabolism of HDL and its components. Of the special interest are the means by which it exerts its apparently protective effect. In this report we characterize the structure of HLD: and describe its compounds, particularly the protein component. We discuss HDL metabolism in light of the relationship of HDL to other lipoprotein classes and relate what little is known of the functions of HDL. We also review the biochemical mechanism by which HDL may protect against cardiovascular disease and discuss further biochemical research that will be necessary for a better understanding of HDL. Interest in HDL has been greatly intensified in recent years, stimulated largely by the finding that HDL is inversely related in HDL has been greatly intensified in recent years, stimulated largely by the finding that HDL is inversely related to coronary artery disease. Case-control and prospective observations of the striking, consistent and independent negative association between HDL levels and coronary vascular events have in turn generated new interest in the structure, composition and metabolism of these fascinating lipoproteins. Several studies carried out in Pakistan also reveal the inverse relation of HDL to IHD/sup 1,2/. This article contains a tremendous amount of information on HDL and its relationship to genetic and environmental factors which should be useful to investigations and clinicians in their evaluation and use of HDL cholesterol measurements to assess hearth disease risk. A knowledge of the structure, function and metabolism of HDL and its components is

21 CFR 862.1475 - Lipoprotein test system.

Science.gov (United States)

2010-04-01

... measure lipoprotein in serum and plasma. Lipoprotein measurements are used in the diagnosis and treatment of lipid disorders (such as diabetes mellitus), atherosclerosis, and various liver and renal diseases...

Human placenta secretes apolipoprotein B-100-containing lipoproteins

DEFF Research Database (Denmark)

Munk-Madsen, Eva; Lindegaard, Marie Louise Skakkebæk; Andersen, Claus B

2004-01-01

Supply of lipids from the mother is essential for fetal growth and development. In mice, disruption of yolk sac cell secretion of apolipoprotein (apo) B-containing lipoproteins results in embryonic lethality. In humans, the yolk sac is vestigial. Nutritional functions are instead established very...... lipoproteins secreted from placental tissue showed spherical particles with a diameter of 47 +/- 10 nm. These results demonstrate that human placenta expresses both apoB and MTP and consequently synthesize and secrete apoB-100-containing lipoproteins. Placental lipoprotein formation constitutes a novel pathway...

Redefining the essential trafficking pathway for outer membrane lipoproteins

Science.gov (United States)

Grabowicz, Marcin; Silhavy, Thomas J.

2017-01-01

The outer membrane (OM) of Gram-negative bacteria is a permeability barrier and an intrinsic antibiotic resistance factor. Lipoproteins are OM components that function in cell wall synthesis, diverse secretion systems, and antibiotic efflux pumps. Moreover, each of the essential OM machines that assemble the barrier requires one or more lipoproteins. This dependence is thought to explain the essentiality of the periplasmic chaperone LolA and its OM receptor LolB that traffic lipoproteins to the OM. However, we show that in strains lacking substrates that are toxic when mislocalized, both LolA and LolB can be completely bypassed by activating an envelope stress response without compromising trafficking of essential lipoproteins. We identify the Cpx stress response as a monitor of lipoprotein trafficking tasked with protecting the cell from mislocalized lipoproteins. Moreover, our findings reveal that an alternate trafficking pathway exists that can, under certain conditions, bypass the functions of LolA and LolB, implying that these proteins do not perform any truly essential mechanistic steps in lipoprotein trafficking. Instead, these proteins’ key function is to prevent lethal accumulation of mislocalized lipoproteins. PMID:28416660

Redefining the essential trafficking pathway for outer membrane lipoproteins.

Science.gov (United States)

Grabowicz, Marcin; Silhavy, Thomas J

2017-05-02

The outer membrane (OM) of Gram-negative bacteria is a permeability barrier and an intrinsic antibiotic resistance factor. Lipoproteins are OM components that function in cell wall synthesis, diverse secretion systems, and antibiotic efflux pumps. Moreover, each of the essential OM machines that assemble the barrier requires one or more lipoproteins. This dependence is thought to explain the essentiality of the periplasmic chaperone LolA and its OM receptor LolB that traffic lipoproteins to the OM. However, we show that in strains lacking substrates that are toxic when mislocalized, both LolA and LolB can be completely bypassed by activating an envelope stress response without compromising trafficking of essential lipoproteins. We identify the Cpx stress response as a monitor of lipoprotein trafficking tasked with protecting the cell from mislocalized lipoproteins. Moreover, our findings reveal that an alternate trafficking pathway exists that can, under certain conditions, bypass the functions of LolA and LolB, implying that these proteins do not perform any truly essential mechanistic steps in lipoprotein trafficking. Instead, these proteins' key function is to prevent lethal accumulation of mislocalized lipoproteins.

Reactive oxygen species production and Brugia pahangi survivorship in Aedes polynesiensis with artificial Wolbachia infection types.

Directory of Open Access Journals (Sweden)

Elizabeth S Andrews

Full Text Available Heterologous transinfection with the endosymbiotic bacterium Wolbachia has been shown previously to induce pathogen interference phenotypes in mosquito hosts. Here we examine an artificially infected strain of Aedes polynesiensis, the primary vector of Wuchereria bancrofti, which is the causative agent of Lymphatic filariasis (LF throughout much of the South Pacific. Embryonic microinjection was used to transfer the wAlbB infection from Aedes albopictus into an aposymbiotic strain of Ae. polynesiensis. The resulting strain (designated "MTB" experiences a stable artificial infection with high maternal inheritance. Reciprocal crosses of MTB with naturally infected wild-type Ae. polynesiensis demonstrate strong bidirectional incompatibility. Levels of reactive oxygen species (ROS in the MTB strain differ significantly relative to that of the wild-type, indicating an impaired ability to regulate oxidative stress. Following a challenge with Brugia pahangi, the number of filarial worms achieving the infective stage is significantly reduced in MTB as compared to the naturally infected and aposymbiotic strains. Survivorship of MTB differed significantly from that of the wild-type, with an interactive effect between survivorship and blood feeding. The results demonstrate a direct correlation between decreased ROS levels and decreased survival of adult female Aedes polynesiensis. The results are discussed in relation to the interaction of Wolbachia with ROS production and antioxidant expression, iron homeostasis and the insect immune system. We discuss the potential applied use of the MTB strain for impacting Ae. polynesiensis populations and strategies for reducing LF incidence in the South Pacific.

Aerosol preparation of intact lipoproteins

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Benner, W Henry [Danville, CA; Krauss, Ronald M [Berkeley, CA; Blanche, Patricia J [Berkeley, CA

2012-01-17

A medical diagnostic method and instrumentation system for analyzing noncovalently bonded agglomerated biological particles is described. The method and system comprises: a method of preparation for the biological particles; an electrospray generator; an alpha particle radiation source; a differential mobility analyzer; a particle counter; and data acquisition and analysis means. The medical device is useful for the assessment of human diseases, such as cardiac disease risk and hyperlipidemia, by rapid quantitative analysis of lipoprotein fraction densities. Initially, purification procedures are described to reduce an initial blood sample to an analytical input to the instrument. The measured sizes from the analytical sample are correlated with densities, resulting in a spectrum of lipoprotein densities. The lipoprotein density distribution can then be used to characterize cardiac and other lipid-related health risks.

Ion mobility analysis of lipoproteins

Science.gov (United States)

Benner, W. Henry; Krauss, Ronald M.; Blanche, Patricia J.

2007-08-21

A medical diagnostic method and instrumentation system for analyzing noncovalently bonded agglomerated biological particles is described. The method and system comprises: a method of preparation for the biological particles; an electrospray generator; an alpha particle radiation source; a differential mobility analyzer; a particle counter; and data acquisition and analysis means. The medical device is useful for the assessment of human diseases, such as cardiac disease risk and hyperlipidemia, by rapid quantitative analysis of lipoprotein fraction densities. Initially, purification procedures are described to reduce an initial blood sample to an analytical input to the instrument. The measured sizes from the analytical sample are correlated with densities, resulting in a spectrum of lipoprotein densities. The lipoprotein density distribution can then be used to characterize cardiac and other lipid-related health risks.

Genetics of Lipid and Lipoprotein Disorders and Traits.

Science.gov (United States)

Dron, Jacqueline S; Hegele, Robert A

2016-01-01

Plasma lipids, namely cholesterol and triglyceride, and lipoproteins, such as low-density lipoprotein (LDL) and high-density lipoprotein, serve numerous physiological roles. Perturbed levels of these traits underlie monogenic dyslipidemias, a diverse group of multisystem disorders. We are on the verge of having a relatively complete picture of the human dyslipidemias and their components. Recent advances in genetics of plasma lipids and lipoproteins include the following: (1) expanding the range of genes causing monogenic dyslipidemias, particularly elevated LDL cholesterol; (2) appreciating the role of polygenic effects in such traits as familial hypercholesterolemia and combined hyperlipidemia; (3) accumulating a list of common variants that determine plasma lipids and lipoproteins; (4) applying exome sequencing to identify collections of rare variants determining plasma lipids and lipoproteins that via Mendelian randomization have also implicated gene products such as NPC1L1 , APOC3 , LDLR , APOA5 , and ANGPTL4 as causal for atherosclerotic cardiovascular disease; and (5) using naturally occurring genetic variation to identify new drug targets, including inhibitors of apolipoprotein (apo) C-III, apo(a), ANGPTL3, and ANGPTL4. Here, we compile this disparate range of data linking human genetic variation to plasma lipids and lipoproteins, providing a "one stop shop" for the interested reader.

Revisiting the Gram-negative lipoprotein paradigm.

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LoVullo, Eric D; Wright, Lori F; Isabella, Vincent; Huntley, Jason F; Pavelka, Martin S

2015-05-01

The processing of lipoproteins (Lpps) in Gram-negative bacteria is generally considered an essential pathway. Mature lipoproteins in these bacteria are triacylated, with the final fatty acid addition performed by Lnt, an apolipoprotein N-acyltransferase. The mature lipoproteins are then sorted by the Lol system, with most Lpps inserted into the outer membrane (OM). We demonstrate here that the lnt gene is not essential to the Gram-negative pathogen Francisella tularensis subsp. tularensis strain Schu or to the live vaccine strain LVS. An LVS Δlnt mutant has a small-colony phenotype on sucrose medium and increased susceptibility to globomycin and rifampin. We provide data indicating that the OM lipoprotein Tul4A (LpnA) is diacylated but that it, and its paralog Tul4B (LpnB), still sort to the OM in the Δlnt mutant. We present a model in which the Lol sorting pathway of Francisella has a modified ABC transporter system that is capable of recognizing and sorting both triacylated and diacylated lipoproteins, and we show that this modified system is present in many other Gram-negative bacteria. We examined this model using Neisseria gonorrhoeae, which has the same Lol architecture as that of Francisella, and found that the lnt gene is not essential in this organism. This work suggests that Gram-negative bacteria fall into two groups, one in which full lipoprotein processing is essential and one in which the final acylation step is not essential, potentially due to the ability of the Lol sorting pathway in these bacteria to sort immature apolipoproteins to the OM. This paper describes the novel finding that the final stage in lipoprotein processing (normally considered an essential process) is not required by Francisella tularensis or Neisseria gonorrhoeae. The paper provides a potential reason for this and shows that it may be widespread in other Gram-negative bacteria. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Heritability of Biomarkers of Oxidized Lipoproteins: Twin Pair Study.

Science.gov (United States)

Rao, Fangwen; Schork, Andrew J; Maihofer, Adam X; Nievergelt, Caroline M; Marcovina, Santica M; Miller, Elizabeth R; Witztum, Joseph L; O'Connor, Daniel T; Tsimikas, Sotirios

2015-07-01

To determine whether biomarkers of oxidized lipoproteins are genetically determined. Lipoprotein(a) (Lp[a]) is a heritable risk factor and carrier of oxidized phospholipids (OxPL). We measured oxidized phospholipids on apolipoprotein B-containing lipoproteins (OxPL-apoB), Lp(a), IgG, and IgM autoantibodies to malondialdehyde-modified low-density lipoprotein, copper oxidized low-density lipoprotein, and apoB-immune complexes in 386 monozygotic and dizygotic twins to estimate trait heritability (h(2)) and determine specific genetic effects among traits. A genome-wide linkage study followed by genetic association was performed. The h(2) (scale: 0-1) for Lp(a) was 0.91±0.01 and for OxPL-apoB 0.87±0.02, which were higher than physiological, inflammatory, or lipid traits. h(2) of IgM malondialdehyde-modified low-density lipoprotein, copper oxidized low-density lipoprotein, and apoB-immune complexes were 0.69±0.04, 0.67±0.05, and 0.80±0.03, respectively, and for IgG malondialdehyde-modified low-density lipoprotein, copper oxidized low-density lipoprotein, and apoB-immune complexes 0.62±0.05, 0.52±0.06, and 0.53±0.06, respectively. There was an inverse correlation between the major apo(a) isoform and OxPL-apoB (R=-0.49; Plipoprotein and copper oxidized low-density lipoprotein, and apoB-immune complexes. Sib-pair genetic linkage of the Lp(a) trait revealed that single nucleotide polymorphism rs10455872 was significantly associated with OxPL-apoB after adjusting for Lp(a). OxPL-apoB and other biomarkers of oxidized lipoproteins are highly heritable cardiovascular risk factors that suggest novel genetic origins of atherothrombosis. © 2015 American Heart Association, Inc.

Isolation and characterization of human apolipoprotein M-containing lipoproteins

DEFF Research Database (Denmark)

Christoffersen, Christina; Nielsen, Lars Bo; Axler, Olof

2006-01-01

Apolipoprotein M (apoM) is a novel apolipoprotein with unknown function. In this study, we established a method for isolating apoM-containing lipoproteins and studied their composition and the effect of apoM on HDL function. ApoM-containing lipoproteins were isolated from human plasma...... with immunoaffinity chromatography and compared with lipoproteins lacking apoM. The apoM-containing lipoproteins were predominantly of HDL size; approximately 5% of the total HDL population contained apoM. Mass spectrometry showed that the apoM-containing lipoproteins also contained apoJ, apoA-I, apoA-II, apoC-I, apo...

Lipoprotein (a) Blood Test: MedlinePlus Lab Test Information

Science.gov (United States)

... this page: https://medlineplus.gov/labtests/lipoproteinabloodtest.html Lipoprotein (a) Blood Test To use the sharing features ... this page, please enable JavaScript. What is a Lipoprotein (a) Blood Test? A lipoprotein (a) test measures ...

Changes in lipoprotein kinetics associated with type 2 diabetes affect the distribution of lipopolysaccharides among lipoproteins.

Science.gov (United States)

Vergès, Bruno; Duvillard, Laurence; Lagrost, Laurent; Vachoux, Christelle; Garret, Céline; Bouyer, Karine; Courtney, Michael; Pomié, Céline; Burcelin, Rémy

2014-07-01

Lipopolysaccharides (LPSs) are inflammatory components of the outer membrane of Gram-negative bacteria and, in plasma, are mostly associated with lipoproteins. This association is thought to promote their catabolism while reducing their proinflammatory effects. Our aim was to determine the impact of lipoprotein kinetics on plasma LPS distribution and how it may affect patients with type 2 diabetes mellitus (T2DM). We performed a kinetic study in 30 individuals (16 T2DM patients, 14 controls) and analyzed the impact of changes in lipoprotein kinetics on LPS distribution among lipoproteins. Plasma LPS levels in T2DM patients were not different from those in controls, but LPS distribution in the two groups was different. Patients with T2DM had higher LPS-very low-density lipoprotein (VLDL; 31% ± 7% vs 22% ± 11%, P = .002), LPS-high-density lipoprotein (HDL; 29% ± 9% vs 19% ± 10%, P = .015), free (nonlipoprotein bound) LPS (10% ± 4% vs 7% ± 4%, P = .043) and lower LPS-low-density lipoprotein (LDL; 30% ± 13% vs 52% ± 16%, P = .001). In multivariable analysis, VLDL-LPS was associated with HDL-LPS (P < .0001); LDL-LPS was associated with VLDL-LPS (P = .004), and VLDL apolipoprotein (apo) B100 catabolism (P = .002); HDL-LPS was associated with free LPS (P < .0001) and VLDL-LPS (P = .033); free LPS was associated with HDL-LPS (P < .0001). In a patient featuring a dramatic decrease in VLDL catabolism due to apoA-V mutation, LDL-LPS was severely decreased (0.044 EU/mL vs 0.788 EU/mL in controls). The difference between T2DM patients and controls for LDL-LPS fraction was no longer significant after controlling for VLDL apoB100 total fractional catabolic rate. Our data suggest that in humans, free LPS transfers first to HDL and then to VLDL, whereas the LPS-bound LDL fraction is mainly derived from VLDL catabolism; the latter may hence represent a LPS catabolic pathway. T2DM patients show lower LDL-LPS secondary to reduced VLDL catabolism, which may represent an

Oxidized low-density lipoprotein in postmenopausal women

DEFF Research Database (Denmark)

Jankowski, Vera; Just, Alexander R; Pfeilschifter, Johannes

2014-01-01

BACKGROUND: Oxidized low-density lipoprotein (oxLDL) leads to atherosclerosis and cardiovascular disease, the most frequent causes of death worldwide. After menopause, lipid and lipoprotein metabolism changes and women are at greater risk of cardiovascular disease compared to fertile women. The aim.......10-0.43). Although intima-media thickness did not differ, postmenopausal women with serous oxLDL had more often atherosclerotic plaques compared to women without oxLDL (6/66 vs. 0/467; P lipoprotein, impaired glucose intolerance, and DBP were independently associated...... with the occurrence of oxLDL. If oxLDL was present, higher high-density lipoprotein and glucose intolerance were associated with higher concentrations of oxLDL. In contrast, higher blood urea concentrations were associated with lower concentrations of oxLDL. CONCLUSION: This study presents the prevalence...

Cholesterol efflux from THP-1 macrophages is impaired by the fatty acid component from lipoprotein hydrolysis by lipoprotein lipase.

Science.gov (United States)

Yang, Yanbo; Thyagarajan, Narmadaa; Coady, Breanne M; Brown, Robert J

2014-09-05

Lipoprotein lipase (LPL) is an extracellular lipase that primarily hydrolyzes triglycerides within circulating lipoproteins. Macrophage LPL contributes to atherogenesis, but the mechanisms behind it are poorly understood. We hypothesized that the products of lipoprotein hydrolysis generated by LPL promote atherogenesis by inhibiting the cholesterol efflux ability by macrophages. To test this hypothesis, we treated human THP-1 macrophages with total lipoproteins that were hydrolyzed by LPL and we found significantly reduced transcript levels for the cholesterol transporters ATP binding cassette transporter A1 (ABCA1), ABCG1, and scavenger receptor BI. These decreases were likely due to significant reductions for the nuclear receptors liver-X-receptor-α, peroxisome proliferator activated receptor (PPAR)-α, and PPAR-γ. We prepared a mixture of free fatty acids (FFA) that represented the ratios of FFA species within lipoprotein hydrolysis products, and we found that the FFA mixture also significantly reduced cholesterol transporters and nuclear receptors. Finally, we tested the efflux of cholesterol from THP-1 macrophages to apolipoprotein A-I, and we found that the treatment of THP-1 macrophages with the FFA mixture significantly attenuated cholesterol efflux. Overall, these data show that the FFA component of lipoprotein hydrolysis products generated by LPL may promote atherogenesis by inhibiting cholesterol efflux, which partially explains the pro-atherogenic role of macrophage LPL. Copyright © 2014 Elsevier Inc. All rights reserved.

High density lipoprotein (HDL)-associated sphingosine 1-phosphate (S1P) inhibits macrophage apoptosis by stimulating STAT3 activity and survivin expression.

Science.gov (United States)

Feuerborn, Renata; Becker, Susen; Potì, Francesco; Nagel, Petra; Brodde, Martin; Schmidt, Harmut; Christoffersen, Christina; Ceglarek, Uta; Burkhardt, Ralph; Nofer, Jerzy-Roch

2017-02-01

Macrophage apoptosis is critically involved in atherosclerosis. We here examined the effect of anti-atherogenic high density lipoprotein (HDL) and its component sphingosine-1-phosphate (S1P) on apoptosis in RAW264.7 murine macrophages. Mitochondrial or endoplasmic reticulum-dependent apoptosis was induced by exposure of macrophages to etoposide or thapsigargin/fukoidan, respectively. Cell death induced by these compounds was inhibited by S1P as inferred from reduced annexin V binding, TUNEL staining, and caspase 3, 9 and 12 activities. S1P induced expression of the inhibitor of apoptosis protein (IAP) family proteins cIAP1, cIAP2 and survivin, but only the inhibitor of survivin expression YM155 and not the cIAP1/2 blocker GDC0152 reversed the inhibitory effect of S1P on apoptosis. Moreover, S1P activated signal transducer and activator of transcription 3 (STAT3) and Janus kinase 2 (JAK2) and the stimulatory effect of S1P on survivin expression and inhibitory effects on apoptosis were attenuated by STAT3 or JAK2 inhibitors, S3I-201 or AG490, respectively. The effects of S1P on STAT3 activation, survivin expression and macrophage apoptosis were emulated by HDL, HDL lipids, and apolipoprotein (apo) M-containing HDL, but not by apoA-I or HDL deprived of S1P or apoM. In addition, JTE013 and CAY10444, S1P receptor 2 and 3 antagonists, respectively, compromised the S1P and HDL capacities to stimulate STAT3 activation and survivin expression, and to inhibit apoptosis. HDL-associated S1P inhibits macrophage apoptosis by stimulating STAT3 activity and survivin expression. The suppression of macrophage apoptosis may represent a novel mechanism utilized by HDL to exert its anti-atherogenic effects. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Effect of apolipoprotein E-free high density lipoproteins on cholesterol metabolism in cultured pig hepatocytes

International Nuclear Information System (INIS)

Bachorik, P.S.; Virgil, D.G.; Kwiterovich, P.O. Jr.

1987-01-01

We studied cholesterol synthesis from [ 14 C]acetate, cholesterol esterification from [ 14 C]oleate, and cellular cholesterol and cholesteryl ester levels after incubating cells with apoE-free high density lipoproteins (HDL) or low density lipoproteins (LDL). LDL suppressed synthesis by up to 60%, stimulated esterification by up to 280%, and increased cell cholesteryl ester content about 4-fold. Esterification increased within 2 h, but synthesis was not suppressed until after 6 h. ApoE-free HDL suppressed esterification by about 50% within 2 h. Cholesterol synthesis was changed very little within 6 h, unless esterification was maximally suppressed; synthesis was then stimulated about 4-fold. HDL lowered cellular unesterified cholesterol by 13-20% within 2 h and promoted the removal of newly synthesized cholesterol and cholesteryl esters. These changes were transient; by 24 h, both esterification and cellular unesterified cholesterol returned to control levels, and cholesteryl esters increased 2-3-fold. HDL core lipid was taken up selectively from 125 I-labeled [ 3 H]cholesteryl ester- and ether-labeled HDL. LDL core lipid uptake was proportional to LDL apoprotein uptake. The findings suggest that 1) the cells respond initially to HDL or LDL with changes in esterification, and 2) HDL mediates both the removal of free cholesterol from the cell and the delivery of HDL cholesteryl esters to the cell

Oxidation of cholesterol moiety of low density lipoprotein in the presence of human endothelial cells or Cu+2 ions: identification of major products and their effects.

Science.gov (United States)

Bhadra, S; Arshad, M A; Rymaszewski, Z; Norman, E; Wherley, R; Subbiah, M T

1991-04-15

Oxidation of lipoproteins is believed to play a key role in atherogenesis. In this study, low density lipoproteins (LDL) was subjected to oxidation in the presence of either human umbilical vein endothelial cells or with Cu+2 ions and the major oxides formed were identified. While cholesterol-alpha-epoxide (C-alpha EP) was the major product of cholesterol peroxidation in the presence of endothelial cells, cholest-3,5-dien-7-one (CD) predominated in the presence of Cu+2 ion. Both steroids were identified by gas chromatography/mass spectrometry. HDL cholesterol was resistant to oxidation. When tested on human skin fibroblasts in culture C-alpha EP (10 micrograms/ml) caused marked stimulation of 14C-oleate incorporation into cholesterol esters, while CD stimulated cholesterol esterification only mildly. These studies show that a) C-alpha EP is the major peroxidation product of LDL cholesterol moiety in the presence of endothelial cells and b) it causes marked stimulation of cholesterol esterification in cells. C-alpha EP may play a key role in increasing cholesterol esterification noted in atherogenesis.

Inhibition of triacylglycerol and apoprotein B secretion and of low density lipoprotein binding in Hep G2 cells by eicosapentaenoic acid

International Nuclear Information System (INIS)

Wong, S.H.; Nestel, P.J.

1987-01-01

The consumption of long chain polyunsaturated fatty acids of fish oils leads to profound lowering of plasma triacylglyercol (TAG) but not of plasma cholesterol. Reasons for this were investigated with the human hepatoma cell line, the Hep G2 cell. Incubations with oleic acid (OA), linoleic acid (LA) and the characteristic marine fatty acid eicosapentaenoic acid (EPA) enriched cellular TAG mass, though least with EPA. However, secretion of very low density lipoprotein (VLDL)-TAG and apoprotein B (apo B), measured from [ 3 H]-glycerol and [ 3 H]-leucine was markedly inhibited by EPA. Preincubation with LA reduced VLDL-TAG but not apo B secretion in comparison with OA which stimulated both. A possible effect on low density lipoprotein (LDL) removal was studied by measuring [ 125 I]-LDL binding. Preincubation with either EPA or LA inhibited the saturable binding of LDL, observed with OA and control incubations. The binding of lipoproteins containing chylomicron remnants was not affected by any of the fatty acids

Spatial and Temporal Variation in Aedes aegypti and Aedes albopictus (Diptera: Culicidae) Numbers in the Yogyakarta Area of Java, Indonesia, With Implications for Wolbachia Releases.

Science.gov (United States)

Tantowijoyo, W; Arguni, E; Johnson, P; Budiwati, N; Nurhayati, P I; Fitriana, I; Wardana, S; Ardiansyah, H; Turley, A P; Ryan, P; O'Neill, S L; Hoffmann, A A

2016-01-01

of mosquito vector populations, particularly through Wolbachia endosymbionts. The success of these strategies depends on understanding the dynamics of vector populations. In preparation for Wolbachia releases around Yogyakarta, we have studied Aedes populations in five hamlets. Adult monitoring with BioGent- Sentinel (BG-S) traps indicated that hamlet populations had different dynamics across the year; while there was an increase in Aedes aegypti (L.) and Aedes albopictus (Skuse) numbers in the wet season, species abundance remained relatively stable in some hamlets but changed markedly (>2 fold) in others. Local rainfall a month prior to monitoring partly predicted numbers of Ae. aegypti but not Ae. albopictus. Site differences in population size indicated by BG-S traps were also evident in ovitrap data. Egg or larval collections with ovitraps repeated at the same location suggested spatial autocorrelation (<250 m) in the areas of the hamlets where Ae. aegypti numbers were high. Overall, there was a weak negative association (r<0.43) between Ae. aegypti and Ae. albopictus numbers in ovitraps when averaged across collections. Ae. albopictus numbers in ovitraps and BG-S traps were positively correlated with vegetation around areas where traps were placed, while Ae. aegypti were negatively correlated with this feature. These data inform intervention strategies by defining periods when mosquito densities are high, highlighting the importance of local site characteristics on populations, and suggesting relatively weak interactions between Ae. aegypti and Ae. albopictus. They also indicate local areas within hamlets where consistently high mosquito densities may influence Wolbachia invasions and other interventions.

Peroxisome Proliferator Activated Receptors and Lipoprotein Metabolism

NARCIS (Netherlands)

Kersten, A.H.

2008-01-01

Plasma lipoproteins are responsible for carrying triglycerides and cholesterol in the blood and ensuring their delivery to target organs. Regulation of lipoprotein metabolism takes place at numerous levels including via changes in gene transcription. An important group of transcription factors that

Structural studies on lipoprotein lipase

International Nuclear Information System (INIS)

Socorro, L.

1985-01-01

The structure of lipoprotein lipase is not known. The lack of information on its primary sequence has been due to the inability of preparing it in homogeneous and stable form. This research has focused on the structural characterization of lipoprotein lipase. The first approach taken was to develop a purification method using bovine milk and affinity chromatography on heparin-Sepharose. The protein obtained was a heterogeneous peak with the activity shifted towards the trailing edge fractions. These fractions only presented a 55 Kdalton band on polyacrylamide gel electrophoresis. Monoclonal antibodies against this band detected an endogenous, phenyl methane sulfonyl fluoride-sensitive protease responsible for the presence of lower molecular weight fragments. The second approach was to label the lipoprotein lipase with a radioactive, active site, directed probe. After incubation and affinity chromatography a complex [ 3 H]inhibitor enzyme was isolated with a stoichiometry of 1.00 +/- 0.2. The complex was digested with CNBr and the insoluble peptides at low ionic strength (>90% [ 3 H]dpm) were used for further purification. Differential extraction of the [ 3 H]-peptide, digestion with S. aureus V8 protease, and high performance liquid chromatography yielded a hexapeptide with a composition consistent with the consensus sequence of the active site peptides of many serine-esterase. This and the kinetic data imply this being the mechanism of action for lipoprotein lipase

Recombinant Lipoproteins as Novel Vaccines with Intrinsic Adjuvant.

Science.gov (United States)

Chong, Pele; Huang, Jui-Hsin; Leng, Chih-Hsiang; Liu, Shih-Jen; Chen, Hsin-Wei

2015-01-01

A core platform technology for high production of recombinant lipoproteins with built-in immunostimulator for novel subunit vaccine development has been established. This platform technology has the following advantages: (1) easily convert antigen into lipidated recombinant protein using a fusion sequence containing lipobox and express high level (50-150mg/L) in Escherichia coli; (2) a robust high-yield up- and downstream bioprocess for lipoprotein production is successfully developed to devoid endotoxin contamination; (3) the lipid moiety of recombinant lipoproteins, which is identical to that of bacterial lipoproteins is recognized as danger signals by the immune system (Toll-like receptor 2 agonist), so both innate and adaptive immune responses can be induced by lipoproteins; and (4) successfully demonstrate the feasibility and safety of this core platform technology in meningococcal group B subunit vaccine, dengue subunit vaccine, novel subunit vaccine against Clostridium difficile-associated diseases, and HPV-based immunotherapeutic vaccines in animal model studies. © 2015 Elsevier Inc. All rights reserved.

Skeletal muscle insulin resistance associated with cholesterol-induced activation of macrophages is prevented by high density lipoprotein.

Directory of Open Access Journals (Sweden)

Andrew L Carey

Full Text Available BACKGROUND: Emerging evidence suggests that high density lipoprotein (HDL may modulate glucose metabolism through multiple mechanisms including pancreatic insulin secretion as well as insulin-independent glucose uptake into muscle. We hypothesized that HDL may also increase skeletal muscle insulin sensitivity via cholesterol removal and anti-inflammatory actions in macrophages associated with excess adiposity and ectopic lipid deposition. METHODS: Human primary and THP-1 macrophages were treated with vehicle (PBS or acetylated low density lipoprotein (acLDL with or without HDL for 18 hours. Treatments were then removed, and macrophages were incubated with fresh media for 4 hours. This conditioned media was then applied to primary human skeletal myotubes derived from vastus lateralis biopsies taken from patients with type 2 diabetes to examine insulin-stimulated glucose uptake. RESULTS: Conditioned media from acLDL-treated primary and THP-1 macrophages reduced insulin-stimulated glucose uptake in primary human skeletal myotubes compared with vehicle (primary macrophages, 168±21% of basal uptake to 104±19%; THP-1 macrophages, 142±8% of basal uptake to 108±6%; P<0.05. This was restored by co-treatment of macrophages with HDL. While acLDL increased total intracellular cholesterol content, phosphorylation of c-jun N-terminal kinase and secretion of pro- and anti-inflammatory cytokines from macrophages, none were altered by co-incubation with HDL. Insulin-stimulated Akt phosphorylation in human skeletal myotubes exposed to conditioned media was unaltered by either treatment condition. CONCLUSION: Inhibition of insulin-stimulated glucose uptake in primary human skeletal myotubes by conditioned media from macrophages pre-incubated with acLDL was restored by co-treatment with HDL. However, these actions were not linked to modulation of common pro- or anti-inflammatory mediators or insulin signaling via Akt.

Effects of gemfibrozil or simvastatin on apolipoprotein-B-containing lipoproteins, apolipoprotein-CIII and lipoprotein(a) in familial combined hyperlipidaemia

NARCIS (Netherlands)

Bredie, S. J.; Westerveld, H. T.; Knipscheer, H. C.; de Bruin, T. W.; Kastelein, J. J.; Stalenhoef, A. F.

1996-01-01

Familial combined hyperlipidaemia (FCH), characterized by elevated very-low-density lipoprotein (VLDL) and/or low-density lipoprotein (LDL), is associated with an increased prevalence of premature cardiovascular disease. Therefore, lipid-lowering is frequently indicated. We evaluated in a parallel,

Human Lipoproteins at Model Cell Membranes

DEFF Research Database (Denmark)

Browning, K L; Lind, T K; Maric, S

2017-01-01

High and low density lipoproteins (HDL and LDL) are thought to play vital roles in the onset and development of atherosclerosis; the biggest killer in the western world. Key issues of initial lipoprotein (LP) interactions at cellular membranes need to be addressed including LP deposition and lipid...... exchange. Here we present a protocol for monitoring the in situ kinetics of lipoprotein deposition and lipid exchange/removal at model cellular membranes using the non-invasive, surface sensitive methods of neutron reflection and quartz crystal microbalance with dissipation. For neutron reflection, lipid...... support the notion of HDL acting as the 'good' cholesterol, removing lipid material from lipid-loaded cells, whereas LDL acts as the 'bad' cholesterol, depositing lipid material into the vascular wall....

Metabolism of cholesteryl esters of rat very low density lipoproteins.

Science.gov (United States)

Faergeman, O; Havel, R J

1975-06-01

Rat very low density lipoproteins (d smaller than 1.006), biologically labeled in esterified and free cholesterol, were obtained form serum 6 h after intravenous injection of particulate (3-H) cholesterol. When injected into recipient animals, the esterified cholesterol was cleared form plasma with a half-life of 5 min. After 15 min, 71% of the injected esterified (3-H) cholesterol had been taken up by the liver, where it was rapidly hydrolyzed. After 60 min only 3.3% of the amount injected had been transferred, via lipoproteins of intermediate density, to the low density lipoproteins of plasma (d 1.019-1.063). Both uptake in the liver and transfer to low density lipoproteins occurred without change of distribution of 3-H in the various cholesteryl esters. 3-H appearing in esterified cholesterol of high density lipoproteins (d greater than 1.063) was derived from esterification, presumably by lecithin: cholesterol acyltransferase, of simultaneously injected free (3-H) cholesterol. Content of free (3-H) cholesterol in the very low density lipoproteins used for injection could be reduced substantially by incubation with erythrocytes. This procedure, however, increased the rate of clearance of the lipoproteins after injection into recipient rats. These studies show that hepatic removal is the major catabolic pathway for cholesteryl esters of rat very low density lipoproteins and that transfer to low density lipoproteins occurs to only a minor extent.

Alterations of serum cholesterol and serum lipoprotein in breast cancer of women

OpenAIRE

Hasija, Kiran; Bagga, Hardeep K.

2005-01-01

Fasting blood sample of 50 normal subjects (control) and 100 patients of breast cancer were investigated for serum total cholesterol, high density lipoprotein cholesterol, low density lipoprotein cholesterol, very low density lipoprotein, high density lipoprotein cholesterol:low density lipoprotein cholesterol ratio and total cholesterol:high density lipoprotein cholesterol ratio during breast cancer of women. Five cancer stages, types, age groups, parity and menopausal status were undertaken...

The fibrate drug gemfibrozil disrupts lipoprotein metabolism in rainbow trout

International Nuclear Information System (INIS)

Prindiville, John S.; Mennigen, Jan A.; Zamora, Jake M.; Moon, Thomas W.; Weber, Jean-Michel

2011-01-01

Gemfibrozil (GEM) is a fibrate drug consistently found in effluents from sewage treatment plants. This study characterizes the pharmacological effects of GEM on the plasma lipoproteins of rainbow trout (Oncorhynchus mykiss). Our goals were to quantify the impact of the drug on: 1) lipid constituents of lipoproteins (phospholipids (PL), triacylglycerol (TAG), and cholesterol), 2) lipoprotein classes (high, low and very low density lipoproteins), and 3) fatty acid composition of lipoproteins. Potential mechanisms of GEM action were investigated by measuring lipoprotein lipase activity (LPL) and the hepatic gene expression of LPL and of the peroxisome proliferator-activated receptor (PPAR) α, β, and γ isoforms. GEM treatment resulted in decreased plasma lipoprotein levels (- 29%) and a reduced size of all lipoprotein classes (lower PL:TAG ratios). However, the increase in HDL-cholesterol elicited by GEM in humans failed to be observed in trout. Therefore, HDL-cholesterol cannot be used to assess the impact of the drug on fish. GEM also modified lipoprotein composition by reducing the abundance of long-chain n-3 fatty acids, thereby potentially reducing the nutritional quality of exposed fish. The relative gene expression of LPL was increased, but the activity of the enzyme was not, and we found no evidence for the activation of PPAR pathways. The depressing effects of GEM on fish lipoproteins demonstrated here may be a concern in view of the widespread presence of fibrates in aquatic environments. Work is needed to test whether exposure to environmental concentrations of these drugs jeopardizes the capacity of fish for reproduction, temperature acclimation or migratory behaviors.

Analytic ultracentrifugation of lipoproteins: Some current collaborations

International Nuclear Information System (INIS)

Lindgren, F.T.

1987-01-01

This summary briefly reports on three ongoing studies - the heterogeneity of Low Density Lipoproteins (LDL) in the cynomolgus monkey, the domain nature of Apolipoprotein E-3, and the molecular weight of apoB-100 in low density lipoprotein subfractions in normal males. 4 refs

[Methodological aspects of evaluation of potential lipid capacity for peroxidation from the serum levels of TBA-active products during iron ion stimulation].

Science.gov (United States)

Kulikova, A I; Tugusheva, F A; Zubina, I M; Shepilova, I N

2008-05-01

The authors propose a simple and reproducible procedure for using iron ions to stimulate serum lipid peroxidation, with TBA-active products being further determined. The procedure determines the reserve of lipids that can be oxidized during oxidative stress. A combination of direct studies and correlation analysis suggests that low-density lipoproteins and very low-density lipoproteins are the major substrates for lipid peroxidation while high-density lipoproteins show a high resistance to this process. The presented procedure may be used to monitor lipid peroxidation in various conditions and upon various exposures in common laboratory practice.

Prediction of lipoprotein signal peptides in Gram-negative bacteria.

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Juncker, Agnieszka S; Willenbrock, Hanni; Von Heijne, Gunnar; Brunak, Søren; Nielsen, Henrik; Krogh, Anders

2003-08-01

A method to predict lipoprotein signal peptides in Gram-negative Eubacteria, LipoP, has been developed. The hidden Markov model (HMM) was able to distinguish between lipoproteins (SPaseII-cleaved proteins), SPaseI-cleaved proteins, cytoplasmic proteins, and transmembrane proteins. This predictor was able to predict 96.8% of the lipoproteins correctly with only 0.3% false positives in a set of SPaseI-cleaved, cytoplasmic, and transmembrane proteins. The results obtained were significantly better than those of previously developed methods. Even though Gram-positive lipoprotein signal peptides differ from Gram-negatives, the HMM was able to identify 92.9% of the lipoproteins included in a Gram-positive test set. A genome search was carried out for 12 Gram-negative genomes and one Gram-positive genome. The results for Escherichia coli K12 were compared with new experimental data, and the predictions by the HMM agree well with the experimentally verified lipoproteins. A neural network-based predictor was developed for comparison, and it gave very similar results. LipoP is available as a Web server at www.cbs.dtu.dk/services/LipoP/.

Adropin induction of lipoprotein lipase expression in tilapia hepatocytes.

Science.gov (United States)

Lian, Anji; Wu, Keqiang; Liu, Tianqiang; Jiang, Nan; Jiang, Quan

2016-01-01

The peptide hormone adropin plays a role in energy homeostasis. However, biological actions of adropin in non-mammalian species are still lacking. Using tilapia as a model, we examined the role of adropin in lipoprotein lipase (LPL) regulation in hepatocytes. To this end, the structural identity of tilapia adropin was established by 5'/3'-rapid amplification of cDNA ends (RACE). The transcripts of tilapia adropin were ubiquitously expressed in various tissues with the highest levels in the liver and hypothalamus. The prolonged fasting could elevate tilapia hepatic adropin gene expression, whereas no effect of fasting was observed on hypothalamic adropin gene levels. In primary cultures of tilapia hepatocytes, synthetic adropin was effective in stimulating LPL release, cellular LPL content, and total LPL production. The increase in LPL production also occurred with parallel rises in LPL gene levels. In parallel experiments, adropin could elevate cAMP production and up-regulate protein kinase A (PKA) and PKC activities. Using a pharmacological approach, cAMP/PKA and PLC/inositol trisphosphate (IP3)/PKC cascades were shown to be involved in adropin-stimulated LPL gene expression. Parallel inhibition of p38MAPK and Erk1/2, however, were not effective in these regards. Our findings provide, for the first time, evidence that adropin could stimulate LPL gene expression via direct actions in tilapia hepatocytes through the activation of multiple signaling mechanisms. © 2016 Society for Endocrinology.

Learning from biology: synthetic lipoproteins for drug delivery.

Science.gov (United States)

Huang, Huang; Cruz, William; Chen, Juan; Zheng, Gang

2015-01-01

Synthetic lipoproteins represent a relevant tool for targeted delivery of biological/chemical agents (chemotherapeutics, siRNAs, photosensitizers, and imaging contrast agents) into various cell types. These nanoparticles offer a number of advantages for drugs delivery over their native counterparts while retaining their natural characteristics and biological functions. Their ultra-small size (lipoprotein receptors, i.e., low-density lipoprotein receptor (LDLR) and Scavenger receptor class B member 1 (SRB1) that are found in a number of pathological conditions (e.g., cancer, atherosclerosis), make them superior delivery strategies when compared with other nanoparticle systems. We review the various approaches that have been developed for the generation of synthetic lipoproteins and their respective applications in vitro and in vivo. More specifically, we summarize the approaches employed to address the limitation on use of reconstituted lipoproteins by means of natural or recombinant apolipoproteins, as well as apolipoprotein mimetic molecules. Finally, we provide an overview of the advantages and disadvantages of these approaches and discuss future perspectives for clinical translation of these nanoparticles. © 2014 Wiley Periodicals, Inc.

Stimulation of cholesteryl ester synthesis in mouse peritoneal macrophages by cholesterol-rich very low density lipoproteins from the Watanabe heritable hyperlipidemic rabbit, an animal model of familial hypercholesterolemia

International Nuclear Information System (INIS)

Kita, T.; Yokode, M.; Watanabe, Y.; Narumiya, S.; Kawai, C.

1986-01-01

Cholesterol-rich very low density lipoproteins (VLDL) from the homozygous Watanabe heritable hyperlipidemic (WHHL) rabbit induced marked cholesteryl ester accumulation in mouse peritoneal macrophages. This WHHL rabbit, an animal model of human familial hypercholesterolemia, has severe hypercholesterolemia, cutaneous xanthomas, and fulminant atherosclerosis due to the deficiency of the low density lipoprotein (LDL) receptor. When incubated with mouse peritoneal macrophages, the VLDL from WHHL rabbit (WHHL-VLDL) stimulated cholesteryl [ 14 C]oleate synthesis 124-fold more than did VLDL from the normal Japanese White rabbit (control-VLDL). The enhancement in cholesteryl ester synthesis and accumulation of WHHL-VLDL was due to the presence of a high affinity binding receptor site on the macrophage cell surface that mediated the uptake and lysosomal degradation of WHHL-VLDL. Competition studies showed that the uptake and degradation of 125 I-WHHL-VLDL was inhibited by unlabeled excess WHHL-VLDL and beta-migrating VLDL (beta-VLDL), but not LDL. Furthermore, the degradation of WHHL-VLDL was not blocked by either fucoidin, polyinosinic acid, or polyguanylic acid, potent inhibitors of the acetylated (acetyl)-LDL binding site, or by acetyl-LDL. These results suggest that macrophages possess a high affinity receptor that recognizes the cholesterol-rich VLDL present in the plasma of the WHHL rabbit and that the receptor which mediates ingestion of WHHL-VLDL seems to be the same as that for beta-VLDL and leads to cholesteryl ester deposition within macrophages. Thus, the uptake of the cholesterol-rich VLDL from the WHHL rabbit by macrophages in vivo may play a significant role in the pathogenesis of atherosclerosis in the WHHL rabbit

Interrelationships between postprandial lipoprotein B:CIII particle changes and high-density lipoprotein subpopulation profiles in mixed hyperlipoproteinemia.

Science.gov (United States)

Saïdi, Y; Sich, D; Camproux, A; Egloff, M; Federspiel, M C; Gautier, V; Raisonnier, A; Turpin, G; Beucler, I

1999-01-01

We studied the relationships postprandially between triglyceride-rich lipoprotein (TRL) and high-density lipoprotein (HDL) in 11 mixed hyperlipoproteinemia (MHL) and 11 hypercholesterolemia (HCL) patients. The high and prolonged postprandial triglyceridemia response observed in MHL but not HCL patients was essentially dependent on very-low-density lipoprotein (VLDL) changes. This abnormal response was related to decreased lipoprotein lipase (LPL) activity (-48.7%, P<.01) in MHL compared with HCL subjects. Cholesteryl ester transfer protein (CETP) activity was postprandially enhanced only in MHL patients, and this elevation persisted in the late period (+19% at 12 hours, P<.05), sustaining the delayed enrichment of VLDL with cholesteryl ester (CE). The late postprandial period in MHL patients was also characterized by high levels of apolipoprotein B (apoB)-containing lipoproteins with apoCIII ([LpB:CIII] +36% at 12 hours, P<.01) and decreased levels of apoCIII contained in HDL ([LpCIII-HDL] -34% at 12 hours, P<.01), reflecting probably a defective return of apoCIII from TRL toward HDL. In MHL compared with HCL patients, decreased HDL2 levels were related to both HDL2b and HDL2a subpopulations (-57% and -49%, respectively, P<.01 for both) and decreased apoA-I levels (-53%, P<.01) were equally linked to decreased HDL2 with apoA-I only (LpA-I) and HDL2 with both apoA-I and apoA-II ([LpA-I:A-II] -55% and -52%, respectively, P<.01 for both). The significant inverse correlations between the postprandial magnitude of LpB:CIII and HDL2-LpA-I and HDL2b levels in MHL patients underline the close TRL-HDL interrelationships. Our findings indicate that TRL and HDL abnormalities evidenced at fasting were postprandially amplified, tightly interrelated, and persistent during the late fed period in mixed hyperlipidemia. Thus, these fasting abnormalities are likely postprandially originated and may constitute proatherogenic lipoprotein disorders additional to the HCL in MHL patients.

One precursor, three apolipoproteins: the relationship between two crustacean lipoproteins, the large discoidal lipoprotein and the high density lipoprotein/β-glucan binding protein.

Science.gov (United States)

Stieb, Stefanie; Roth, Ziv; Dal Magro, Christina; Fischer, Sabine; Butz, Eric; Sagi, Amir; Khalaila, Isam; Lieb, Bernhard; Schenk, Sven; Hoeger, Ulrich

2014-12-01

The novel discoidal lipoprotein (dLp) recently detected in the crayfish, differs from other crustacean lipoproteins in its large size, apoprotein composition and high lipid binding capacity, We identified the dLp sequence by transcriptome analyses of the hepatopancreas and mass spectrometry. Further de novo assembly of the NGS data followed by BLAST searches using the sequence of the high density lipoprotein/1-glucan binding protein (HDL-BGBP) of Astacus leptodactylus as query revealed a putative precursor molecule with an open reading frame of 14.7 kb and a deduced primary structure of 4889 amino acids. The presence of an N-terminal lipid bind- ing domain and a DUF 1943 domain suggests the relationship with the large lipid transfer proteins. Two-putative dibasic furin cleavage sites were identified bordering the sequence of the HDL-BGBP. When subjected to mass spectroscopic analyses, tryptic peptides of the large apoprotein of dLp matched the N-terminal part of the precursor, while the peptides obtained for its small apoprotein matched the C-terminal part. Repeating the analysis in the prawn Macrobrachium rosenbergii revealed a similar protein with identical domain architecture suggesting that our findings do not represent an isolated instance. Our results indicate that the above three apolipoproteins (i.e HDL-BGBP and both the large and the small subunit of dLp) are translated as a large precursor. Cleavage at the furin type sites releases two subunits forming a heterodimeric dLP particle, while the remaining part forms an HDL-BGBP whose relationship with other lipoproteins as well as specific functions are yet to be elucidated.

IS LIPOPROTEIN (A A PREDICTOR OF CORONARY ARTERY DISEASE SEVERITY?

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Tayyebeh Miandoabi

2010-12-01

Full Text Available Abstract    INTRODUCTION: Studies on the association between the plasma concentration of lipoprotein (a and coronary heart disease (CHD have reported conflicting findings.    METHOD AND MATERIALS: The objective of the present study was to evaluate the association between serum levels of lipoprotein (a and ischemic heart disease as well as other cardiovascular risk factors in a population-based study. Lipoprotein (a serum was measured in 142 patients with chronic stable angina undergoing clinically indicated coronary angiography. Lipid profile, fasting blood glucose, anthropometric and clinical parameters were analyzed.    RESULTS: Lipoprotein (a levels were significantly associated with coronary artery stenosis in men, but not in women. Also, an direct association between mean levels of lipoprotein (a and coronary artery stenosis in men younger than 55 years old and an inverse association in men older than 55 years old were observed.     CONCLUSION: Multivariate analysis revealed that lipoprotein (a was considered an independent predictor for severity of CAD in men, especially in younger ages.      Keywords: Lipoprotein (a, cardiovascular risk factors, Ischemic heart disease, coronary angiography.

The Acylation State of Surface Lipoproteins of Mollicute Acholeplasma laidlawii*

Science.gov (United States)

Serebryakova, Marina V.; Demina, Irina A.; Galyamina, Maria A.; Kondratov, Ilya G.; Ladygina, Valentina G.; Govorun, Vadim M.

2011-01-01

Acylation of the N-terminal Cys residue is an essential, ubiquitous, and uniquely bacterial posttranslational modification that allows anchoring of proteins to the lipid membrane. In Gram-negative bacteria, acylation proceeds through three sequential steps requiring lipoprotein diacylglyceryltransferase, lipoprotein signal peptidase, and finally lipoprotein N-acyltransferase. The apparent lack of genes coding for recognizable homologs of lipoprotein N-acyltransferase in Gram-positive bacteria and Mollicutes suggests that the final step of the protein acylation process may be absent in these organisms. In this work, we monitored the acylation state of eight major lipoproteins of the mollicute Acholeplasma laidlawii using a combination of standard two-dimensional gel electrophoresis protein separation, blotting to nitrocellulose membranes, and MALDI-MS identification of modified N-terminal tryptic peptides. We show that for each A. laidlawii lipoprotein studied a third fatty acid in an amide linkage on the N-terminal Cys residue is present, whereas diacylated species were not detected. The result thus proves that A. laidlawii encodes a lipoprotein N-acyltransferase activity. We hypothesize that N-acyltransferases encoded by genes non-homologous to N-acyltransferases of Gram-negative bacteria are also present in other mollicutes and Gram-positive bacteria. PMID:21540185

Bio F1B hamster: a unique animal model with reduced lipoprotein lipase activity to investigate nutrient mediated regulation of lipoprotein metabolism

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Cornish Marion L

2007-12-01

Full Text Available Abstract Background Bio F1B hamster is an inbred hybrid strain that is highly susceptible to diet-induced atherosclerosis. We previously reported that feeding a high fat fish oil diet to Bio F1B hamster caused severe hyperlipidaemia. In this study we compared the effects of various diets in the Bio F1B hamster and the Golden Syrian hamster, which is an outbred hamster strain to investigate whether genetic background plays an important role in dietary fat mediated regulation of lipoprotein metabolism. We further investigated the mechanisms behind diet-induced hyperlipidaemia in F1B hamster. Methods The Bio F1B and Golden Syrian hamsters, 8 weeks old, were fed high fat diets rich in either monounsaturated fatty acids, an n-6: n-3 ratio of 5 or a fish oil diet for 4 weeks. Animals were fasted overnight and blood and tissue samples were collected. Plasma was fractionated into various lipoprotein fractions and assayed for triacylglycerol and cholesterol concentrations. Plasma lipoprotein lipase activity was measured using radioisotope method. Microsomal triglyceride transfer protein activity was measured in the liver and intestine. Plasma apolipoproteinB48, -B100 and apolipoprotein E was measured using Western blots. Two-way ANOVA was used to determine the effect of diet type and animal strain. Results The fish oil fed F1B hamsters showed milky plasma after a 14-hour fast. Fish oil feeding caused accumulation of apolipoproteinB48 containing lipoprotein particles suggesting hindrance of triglyceride-rich lipoprotein clearance. There was no significant effect of diet or strain on hepatic or intestinal microsomal triglyceride transfer protein activity indicating that hyperlipidaemia is not due to an increase in the assembly or secretion of lipoprotein particles. F1B hamsters showed significantly reduced levels of lipoprotein lipase activity, which was inhibited by fish oil feeding. Conclusion Evidence is presented for the first time that alterations in

Triglyceride-rich lipoproteins and high-density lipoprotein cholesterol in patients at high risk of cardiovascular disease: evidence and guidance for management

DEFF Research Database (Denmark)

Chapman, M John; Ginsberg, Henry N; Amarenco, Pierre

2011-01-01

Even at low-density lipoprotein cholesterol (LDL-C) goal, patients with cardiometabolic abnormalities remain at high risk of cardiovascular events. This paper aims (i) to critically appraise evidence for elevated levels of triglyceride-rich lipoproteins (TRLs) and low levels of high......-density lipoprotein cholesterol (HDL-C) as cardiovascular risk factors, and (ii) to advise on therapeutic strategies for management. Current evidence supports a causal association between elevated TRL and their remnants, low HDL-C, and cardiovascular risk. This interpretation is based on mechanistic and genetic...

Immunosuppressive activity of human cord-blood lipoproteins

International Nuclear Information System (INIS)

Forte, T.M.; Davis, P.A.; Curtiss, L.K.

1985-01-01

It is now known that the role of plasma lipoproteins is multifunctional. More recently it has been shown that lipoproteins may regulate immune responses as well. Low-density lipoproteins carrying apolipoprotein B (apoB) are known to suppress phytohemagglutinin (PHA) activated lymphocytes by inhibiting DNA synthesis. More recently, an immunoregulatory role has been described for another apolipoprotein, apoE, which is found in low quantities in normal plasma. In these studies with human umbilical-cord blood the authors were intrigued by two factors: the low level of LDL and hence apoB, and the elevated quantity of apoE. This study examines the hypothesis that apoE may regulate lymphocyte function in the human fetus

Sorting of bacterial lipoproteins to the outer membrane by the Lol system.

Science.gov (United States)

Narita, Shin-ichiro; Tokuda, Hajime

2010-01-01

Bacterial lipoproteins comprise a subset of membrane proteins with a lipid-modified cysteine residue at their amino termini through which they are anchored to the membrane. In Gram-negative bacteria, lipoproteins are localized on either the inner or the outer membrane. The Lol system is responsible for the transport of lipoproteins to the outer membrane.The Lol system comprises an inner-membrane ABC transporter LolCDE complex, a periplasmic carrier protein, LolA, and an outer membrane receptor protein, LolB. Lipoproteins are synthesized as precursors in the cytosol and then translocated across the inner membrane by the Sec translocon to the outer leaflet of the inner membrane, where lipoprotein precursors are processed to mature lipoproteins. The LolCDE complex then mediates the release of outer membrane-specific lipoproteins from the inner membrane while the inner membrane-specific lipoproteins possessing Asp at position 2 are not released by LolCDE because it functions as a LolCDE avoidance signal, causing the retention of these lipoproteins in the inner membrane. A water-soluble lipoprotein-LolA complex is formed as a result of the release reaction mediated by LolCDE. This complex traverses the hydrophilic periplasm to reach the outer membrane, where LolB accepts a lipoprotein from LolA and then catalyzes its incorporation into the inner leaflet of the outer membrane.

Expressions of the low density lipoprotein receptor and 3-hydroxy-3-methylglutaryl coenzyme A reductase genes are stimulated by recombinant platelet-derived growth factor isomers

International Nuclear Information System (INIS)

Roth, M.; Emmons, L.R.; Perruchoud, A.; Block, L.H.

1991-01-01

The plausible role that platelet-derived growth factor (PDGF) has in the localized pathophysiological changes that occur in the arterial wall during development of atherosclerotic lesions led the authors to investigate the influence of recombinant (r)PDGF isomers -AA, -AB, and -BB on the expression of low density lipoprotein receptor (LDL-R) and 3-hydroxy-3-methylglutaryl coenzyme A (HMG0CoA) reductase [(S)-mevalonate:NAD + oxidoreductase (CoA-acylating), EC 1.1.1.88] genes. In addition, they clarified the role of protein kinase C (PKC) in expression of the two genes in human skin fibroblasts and vascular smooth muscle cells. The various rPDGF isoforms are distinct in their ability to activate transcription of both genes: (i) both rPDGF-AA and -BB stimulate transcription of the LDL-R gene; in contrast, rPDGF-BB but not -AA, activates transcription of the HMG-CoA reductase gene; (ii) all recombinant isoforms of PDGF activate transcription of the c-fos gene; (iii) while rPDGF-dependent transcription of the lDL-R gene occurs independently of PKC, transcription of the HMG-CoA reductase gene appears to involve the action of that enzyme

21 CFR 866.5590 - Lipoprotein X immunolog-ical test system.

Science.gov (United States)

2010-04-01

... device that consists of the reagents used to measure by immunochemical techniques lipoprotein X (a high-density lipoprotein) in serum and other body fluids. Measurement of lipoprotein X aids in the diagnosis of obstructive liver disease. (b) Classification. Class I (general controls). The device is exempt from the...

Characterization of the Pseudomonas aeruginosa Lol system as a lipoprotein sorting mechanism.

Science.gov (United States)

Tanaka, Shin-Ya; Narita, Shin-Ichiro; Tokuda, Hajime

2007-05-04

Escherichia coli lipoproteins are localized to either the inner or the outer membrane depending on the residue that is present next to the N-terminal acylated Cys. Asp at position 2 causes the retention of lipoproteins in the inner membrane. In contrast, the accompanying study (9) revealed that the residues at positions 3 and 4 determine the membrane specificity of lipoproteins in Pseudomonas aeruginosa. Since the five Lol proteins involved in the sorting of E. coli lipoproteins are conserved in P. aeruginosa, we examined whether or not the Lol proteins of P. aeruginosa are also involved in lipoprotein sorting but utilize different signals. The genes encoding LolCDE, LolA, and LolB homologues were cloned and expressed. The LolCDE homologue thus purified was reconstituted into proteoliposomes with lipoproteins. When incubated in the presence of ATP and a LolA homologue, the reconstituted LolCDE homologue released lipoproteins, leading to the formation of a LolA-lipoprotein complex. Lipoproteins were then incorporated into the outer membrane depending on a LolB homologue. As revealed in vivo, lipoproteins with Lys and Ser at positions 3 and 4, respectively, remained in proteoliposomes. On the other hand, E. coli LolCDE released lipoproteins with this signal and transferred them to LolA of not only E. coli but also P. aeruginosa. These results indicate that Lol proteins are responsible for the sorting of lipoproteins to the outer membrane of P. aeruginosa, as in the case of E. coli, but respond differently to inner membrane retention signals.

Sex, plasma lipoproteins, and atherosclerosis: prevailing assumptions and outstanding questions.

Science.gov (United States)

Godsland, I F; Wynn, V; Crook, D; Miller, N E

1987-12-01

We review the hypothesis that the incidence of coronary heart disease (CHD) is higher in men than in women due to differences in plasma lipoprotein risk factors between the sexes. Men and women appear to be equally susceptible to the effects of lipoprotein risk factors for CHD, and the difference between the sexes in lipoprotein risk factors for CHD appears to be consistent with their being, at least in part, responsible for the sex difference in CHD. This is apparent both when men and women of equal age are compared, and when age-related variations in the sex differences in plasma lipoproteins and CHD are considered. Differences between the sexes in lipoprotein concentrations are still present when sex differences in adiposity, cigarette smoking, physical activity, and diet are taken into account. Evidence relating these sex differences in CHD and lipoproteins to the effects of sex hormones is critically examined. It is commonly accepted that androgens induce changes in lipoprotein concentrations that would predispose towards CHD, whereas estrogens are held to have opposite effects. However, much of the evidence for this comes from studies of changes associated with administration of synthetic gonadal steroids or with changes in gonadal function. Studies of differences in lipoprotein metabolism in normal men and women are extremely limited. In males high-density lipoprotein (HDL) cholesterol levels fall at puberty, correlating with the rise in plasma testosterone concentrations. In females, HDL levels do not change at puberty, despite the rise in estrogen concentrations. Evidence for lipoprotein changes during the menopause, when estrogen levels decline, is equivocal. Similarly, the evidence for an increase in CHD incidence at the menopause is inconclusive. National mortality data indicate that the decreasing sex difference in CHD after 50 years of age is due to a declining rate of increase in men rather than to an acceleration in CHD incidence in women. In men

Comparison of lipoprotein electrophoresis and apolipoprotein e genotyping in investigating dysbetalipoproteinemia

International Nuclear Information System (INIS)

Ahmed, F.; Kadiki, A.E.

2017-01-01

Dysbetalipoproteinemia is often associated with apolipoprotein E2E2 homozygosity; however, lipoprotein electrophoresis may also be used to assist in the diagnosis. The aim of this study was to compare apolipoprotein E (apo E) genotyping and lipoprotein electrophoresis in investigating dysbetalipoproteinemia. Data were collected over a three-year period from a lipid clinic in a tertiary referral centre and reviewed for apo E genotyping and lipoprotein electrophoresis. Sixty-two patients had both apo E genotyping and lipoprotein electrophoresis. Of these, 16 patients showed broad beta band on electrophoresis. However, only 3 of them had apo E2E2 homozygosity on genotyping. Lipoprotein electrophoresis and apo E genotyping results showed poor concordance. This was primarily due to visual interpretation error of lipoprotein electrophoresis which may over diagnose dysbetalipoproteinemia. (author)

Comparison of Lipoprotein Electrophoresis and Apolipoprotein E Genotyping in Investigating Dysbetalipoproteinemia.

Science.gov (United States)

Ahmed, Farhan; El-Kadiki, Alia; Gibbons, Stephen

2017-06-01

Dysbetalipoproteinemia is often associated with apolipoprotein E2E2 homozygosity; however, lipoprotein electrophoresis may also be used to assist in the diagnosis. The aim of this study was to compare apolipoprotein E (apo E) genotyping and lipoprotein electrophoresis in investigating dysbetalipoproteinemia. Data were collected over a three-year period from a lipid clinic in a tertiary referral centre and reviewed for apo E genotyping and lipoprotein electrophoresis. Sixty-two patients had both apo E genotyping and lipoprotein electrophoresis. Of these, 16 patients showed broad beta band on electrophoresis. However, only 3 of them had apo E2E2 homozygosity on genotyping. Lipoprotein electrophoresis and apo E genotyping results showed poor concordance. This was primarily due to visual interpretation error of lipoprotein electrophoresis which may over diagnose dysbetalipoproteinemia.

Combining the Sterile Insect Technique with Wolbachia-Based Approaches: II--A Safer Approach to Aedes albopictus Population Suppression Programmes, Designed to Minimize the Consequences of Inadvertent Female Release.

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Dongjing Zhang

Full Text Available Due to the absence of a perfect method for mosquito sex separation, the combination of the sterile insect technique and the incompatible insect technique is now being considered as a potentially effective method to control Aedes albopictus. In this present study first we examine the minimum pupal irradiation dose required to induce complete sterility in Wolbachia triple-infected (HC, double-infected (GUA and uninfected (GT female Ae. albopictus. The HC line is a candidate for Ae. albopictus population suppression programmes, but due to the risk of population replacement which characterizes this triple infected line, the individuals to be released need to be additionally irradiated. After determining the minimum irradiation dose required for complete female sterility, we test whether sterilization is sufficient to prevent invasion of the triple infection from the HC females into double-infected (GUA populations. Our results indicate that irradiated Ae. albopictus HC, GUA and GT strain females have decreased fecundity and egg hatch rate when irradiated, inversely proportional to the dose, and the complete sterilization of females can be acquired by pupal irradiation with doses above 28 Gy. PCR-based analysis of F1 and F2 progeny indicate that the irradiated HC females, cannot spread the new Wolbachia wPip strain into a small cage GUA population, released at a 1:5 ratio. Considering the above results, we conclude that irradiation can be used to reduce the risk of population replacement caused by an unintentional release of Wolbachia triple-infected Ae. albopictus HC strain females during male release for population suppression.

Effects of human low and high density lipoproteins on the binding of rat intermediate density lipoproteins to rat liver membranes

International Nuclear Information System (INIS)

Brissette, L.; Nol, S.P.

1986-01-01

Upon incubation with rat liver membranes, radioiodinated rat intermediate density lipoproteins (IDL) interacted with at least two binding sites having a low and a high affinity as demonstrated by the curvilinear Scatchard plots obtained from the specific binding data. The purpose of our work was to identify the nature of these binding sites. Human low density lipoproteins (LDL), contain apolipoprotein B only, and human high density lipoproteins (HDL3), containing neither apolipoprotein B nor E, were both capable of decreasing the specific binding of rat 125 I-IDL. The Scatchard analysis clearly revealed that only the low affinity component was affected by the addition of these human lipoproteins. In fact, the low affinity binding component gradually decreased as the amount of human LDL or HDL3 increased in the binding assay. At a 200-fold excess of human LDL or HDL3, the low affinity binding was totally masked, and the Scatchard plot of the specific 125 I-IDL binding became linear. Only the high affinity binding component was left, enabling a precise measurement of its binding parameters. In a series of competitive displacement experiments in which the binding assay contained a 200-fold excess of human LDL or HDL3, only unlabeled rat IDL effectively displaced the binding of rat 125 I-IDL. We conclude that the low affinity binding of rat IDL to rat liver membranes is due to weak interactions with unspecified lipoprotein binding sites. The camouflage of these sites by human lipoproteins makes possible the study of IDL binding to the high affinity component which likely represents the combined effect of IDL binding to both the remnant and the LDL receptors

Correlation between serum lipoproteins and abdominal fat pad in ...

African Journals Online (AJOL)

GREGORY

2010-08-30

Aug 30, 2010 ... Triglyceride, cholesterol and VLDL concentrations were positively correlated with ... negative correlation was observed between high-density lipoprotein and ... Abbreviations: HDL, High density lipoprotein; VLDL, very low.

Triglyceride-rich lipoproteins and high-density lipoprotein cholesterol in patients at high risk of cardiovascular disease: evidence and guidance for management

NARCIS (Netherlands)

Chapman, M. John; Ginsberg, Henry N.; Amarenco, Pierre; Andreotti, Felicita; Borén, Jan; Catapano, Alberico L.; Descamps, Olivier S.; Fisher, Edward; Kovanen, Petri T.; Kuivenhoven, Jan Albert; Lesnik, Philippe; Masana, Luis; Nordestgaard, Børge G.; Ray, Kausik K.; Reiner, Zeljko; Taskinen, Marja-Riitta; Tokgözoglu, Lale; Tybjærg-Hansen, Anne; Watts, Gerald F.

2011-01-01

Even at low-density lipoprotein cholesterol (LDL-C) goal, patients with cardiometabolic abnormalities remain at high risk of cardiovascular events. This paper aims (i) to critically appraise evidence for elevated levels of triglyceride-rich lipoproteins (TRLs) and low levels of high-density

Triglyceride-rich lipoproteins and high-density lipoprotein cholesterol in patients at high risk of cardiovascular disease: evidence and guidance for management

DEFF Research Database (Denmark)

Chapman, M John; Ginsberg, Henry N; Amarenco, Pierre

2011-01-01

Even at low-density lipoprotein cholesterol (LDL-C) goal, patients with cardiometabolic abnormalities remain at high risk of cardiovascular events. This paper aims (i) to critically appraise evidence for elevated levels of triglyceride-rich lipoproteins (TRLs) and low levels of high-density lipop...

Postprandial Hyperlipidemia and Remnant Lipoproteins.

Science.gov (United States)

Masuda, Daisaku; Yamashita, Shizuya

2017-02-01

Fasting hypertriglyceridemia is positively associated with the morbidity of coronary heart disease (CHD), and postprandial (non-fasting) hypertriglyceridemia is also correlated with the risk status for CHD, which is related to the increase in chylomicron (CM) remnant lipoproteins produced from the intestine. CM remnant particles, as well as oxidized low density lipoprotein (LDL) or very low density lipoprotein (VLDL) remnants, are highly atherogenic and act by enhancing systemic inflammation, platelet activation, coagulation, thrombus formation, and macrophage foam cell formation. The cholesterol levels of remnant lipoproteins significantly correlate with small, dense LDL; impaired glucose tolerance (IGT) and CHD prevalence. We have developed an assay of apolipoprotein (apo)B-48 levels to evaluate the accumulation of CM remnants. Fasting apoB-48 levels correlate with the morbidity of postprandial hypertriglyceridemia, obesity, type III hyperlipoproteinemia, the metabolic syndrome, hypothyroidism, chronic kidney disease, and IGT. Fasting apoB-48 levels also correlate with carotid intima-media thickening and CHD prevalence, and a high apoB-48 level is a significant predictor of CHD risk, independent of the fasting TG level. Diet interventions, such as dietary fibers, polyphenols, medium-chain fatty acids, diacylglycerol, and long-chain n-3 polyunsaturated fatty acids (PUFA), ameliorate postprandial hypertriglyceridemia, moreover, drugs for dyslipidemia (n-3 PUFA, statins, fibrates or ezetimibe) and diabetes concerning incretins (dipeptidyl-peptidase IV inhibitor or glucagon like peptide-1 analogue) may improve postprandial hypertriglyceridemia. Since the accumulation of CM remnants correlates to impaired lipid and glucose metabolism and atherosclerotic cardiovascular events, further studies are required to investigate the characteristics, physiological activities, and functions of CM remnants for the development of new interventions to reduce atherogenicity.

Immune Response to Lipoproteins in Atherosclerosis

Directory of Open Access Journals (Sweden)

Sonia Samson

2012-01-01

Full Text Available Atherosclerosis, the underlying cause of cardiovascular disease, is characterized by chronic inflammation and altered immune response. Cholesterol is a well-known risk factor associated with the development of cardiovascular diseases. Elevated serum cholesterol is unique because it can lead to development of atherosclerosis in animals and humans even in the absence of other risk factors. Modifications of low-density lipoproteins mediated by oxidation, enzymatic degradation, and aggregation result in changes in their function and activate both innate and adaptive immune system. Oxidized low-density lipoprotein (LDL has been identified as one of the most important autoantigens in atherosclerosis. This escape from self-tolerance is dependent on the formation of oxidized phospholipids. The emerging understanding of the importance of immune responses against oxidized LDL in atherosclerosis has focused attention on the possibility of development of novel therapy for atherosclerosis. This review provides an overview of immune response to lipoproteins and the fascinating possibility of developing an immunomodulatory therapy for atherosclerosis.

Serum lipid and lipoprotein patterns of Iranian horses.

Science.gov (United States)

Asadi, F; Asadian, P; Shahriari, A; Pourkabir, M; Kazemi, A

2011-12-01

Patterns of serum biochemical parameters vary among horse breeds. The objective of the present study was to compare serum lipoproteins of Iranian Caspian ponies with those of other horses (Arabs and Thoroughbreds) in the Iranian region. Serum lipoprotein values were determined by agar-agarose gel electrophoresis and measured by scan densitometry. Moreover, serum triglyceride and cholesterol concentrations were determined and the results were analysed by one-way analysis of variance. Serum triglyceride and cholesterol values were 1.13 +/- 0.23 and 2.38 +/- 0.18 mmol/l in Caspian ponies, 1.96 +/- 0.49 and 1.92 +/- 0.25 mmol/l in Arab horses and 1.38 +/- 0.26 and 2.17 +/- 0.53 mmol/l in Thoroughbred horses. The relative percentages of alpha- (72.63 +/- 17.76%) and beta-lipoproteins (29.10 +/- 5.49%) in serum electrophoretic tracings from Caspian ponies were not significantly different from those of other horses (p > 0.05). The lipoprotein phenotype in Caspian ponies may be useful for evaluating metabolic diseases.

The Influence of Decreased Levels of High Density Lipoprotein ...

African Journals Online (AJOL)

very low density lipoprotein cholesterol, and triglyceride were assayed. ... Abiodun and Gwarzo: Association of high density lipoprotein cholesterol with haemolysis in sickle cell disease ... analyses were carried out to determine the correlation.

Secretion of Bacterial Lipoproteins: Through the Cytoplasmic Membrane, the Periplasm and Beyond

Science.gov (United States)

Zückert, Wolfram R.

2014-01-01

Bacterial lipoproteins are peripherally anchored membrane proteins that play a variety of roles in bacterial physiology and virulence in monoderm (single membrane-enveloped, e.g., grampositive) and diderm (double membrane-enveloped, e.g., gram-negative) bacteria. After export of prolipoproteins through the cytoplasmic membrane, which occurs predominantly but not exclusively via the general secretory or Sec pathway, the proteins are lipid-modified at the cytoplasmic membrane in a multistep process that involves sequential modification of a cysteine residue and cleavage of the signal peptide by the signal II peptidase Lsp. In both monoderms and diderms, signal peptide processing is preceded by acylation with a diacylglycerol through preprolipoprotein diacylglycerol transferase (Lgt). In diderms but also some monoderms, lipoproteins are further modified with a third acyl chain through lipoprotein N-acyl transferase (Lnt). Fully modified lipoproteins that are destined to be anchored in the inner leaflet of the outer membrane (OM) are selected, transported and inserted by the Lol (lipoprotein outer membrane localization) pathway machinery, which consists of the inner-membrane (IM) ABC transporterlike LolCDE complex, the periplasmic LolA chaperone and the OM LolB lipoprotein receptor. Retention of lipoproteins in the cytoplasmic membrane results from Lol avoidance signals that were originally described as the “+2 rule”. Surface localization of lipoproteins in diderms is rare in most bacteria, with the exception of several spirochetal species. Type 2 (T2SS) and type 5 (T5SS) secretion systems are involved in secretion of specific surface lipoproteins of γ-proteobacteria. In the model spirochete Borrelia burgdorferi, surface lipoprotein secretion does not follow established sorting rules, but remains dependent on N-terminal peptide sequences. Secretion through the outer membrane requires maintenance of lipoproteins in a translocation-competent unfolded conformation

Preparation and Characterization of Stable α-Synuclein Lipoprotein Particles.

Science.gov (United States)

Eichmann, Cédric; Campioni, Silvia; Kowal, Julia; Maslennikov, Innokentiy; Gerez, Juan; Liu, Xiaoxia; Verasdonck, Joeri; Nespovitaya, Nadezhda; Choe, Senyon; Meier, Beat H; Picotti, Paola; Rizo, Josep; Stahlberg, Henning; Riek, Roland

2016-04-15

Multiple neurodegenerative diseases are caused by the aggregation of the human α-Synuclein (α-Syn) protein. α-Syn possesses high structural plasticity and the capability of interacting with membranes. Both features are not only essential for its physiological function but also play a role in the aggregation process. Recently it has been proposed that α-Syn is able to form lipid-protein particles reminiscent of high-density lipoproteins. Here, we present a method to obtain a stable and homogeneous population of nanometer-sized particles composed of α-Syn and anionic phospholipids. These particles are called α-Syn lipoprotein (nano)particles to indicate their relationship to high-density lipoproteins formed by human apolipoproteins in vivo and of in vitro self-assembling phospholipid bilayer nanodiscs. Structural investigations of the α-Syn lipoprotein particles by circular dichroism (CD) and magic angle solid-state nuclear magnetic resonance (MAS SS-NMR) spectroscopy establish that α-Syn adopts a helical secondary structure within these particles. Based on cryo-electron microscopy (cryo-EM) and dynamic light scattering (DLS) α-Syn lipoprotein particles have a defined size with a diameter of ∼23 nm. Chemical cross-linking in combination with solution-state NMR and multiangle static light scattering (MALS) of α-Syn particles reveal a high-order protein-lipid entity composed of ∼8-10 α-Syn molecules. The close resemblance in size between cross-linked in vitro-derived α-Syn lipoprotein particles and a cross-linked species of endogenous α-Syn from SH-SY5Y human neuroblastoma cells indicates a potential functional relevance of α-Syn lipoprotein nanoparticles. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

In vitro studies on the distribution of probucol among human plasma lipoproteins

International Nuclear Information System (INIS)

Urien, S.; Riant, P.; Albengres, E.; Brioude, R.; Tillement, J.P.

1984-01-01

The role of human plasma lipoproteins as carriers in the blood transport of the cholesterol-lowering and water-insoluble drug, probucol, was investigated in in vitro studies. [ 14 C]Probucol was incubated in whole human blood, a serum pool, individual diluted sera, and isolated protein and lipoprotein fractions. In whole blood, about 90% partitioned in plasma. Following ultracentrifugal fractionation of the serum, it was found that less than 5% distributed in the d greater than 1.20 protein fraction (albumin-rich fraction) and more than 95% in the lipoprotein fractions. The distribution of probucol in the lipoprotein fractions correlated with the lipoprotein total lipid volume under saturation conditions (incubation of isolated lipoprotein fractions) as well as nonsaturation conditions (fractionation of serum exposed to [ 14 C]probucol). Incubation of the albumin-rich fraction and of apolipoproteins originating from the isolated lipoprotein fractions showed that they account for a negligible part in the interaction of probucol with blood components. The probucol uptake of individual sera was shown to be correlated to the lipid content of the serum. When probucol was incubated in erythrocyte suspensions containing variable amounts of lipoproteins, probucol partitioned less in erythrocytes as the lipoprotein concentration increased in the suspension

Dietary fish oil stimulates hepatic low density lipoprotein transport in the rat.

Science.gov (United States)

Ventura, M A; Woollett, L A; Spady, D K

1989-01-01

These studies were undertaken to examine the effect of fish oil, safflower oil, and hydrogenated coconut oil on the major processes that determine the concentration of low density lipoprotein (LDL) in plasma, i.e., the rate of LDL production and the rates of receptor-dependent and receptor-independent LDL uptake in the various organs of the body. When fed at the 20% level, fish oil reduced plasma LDL-cholesterol levels by 38% primarily by increasing LDL receptor activity in the liver. Dietary safflower oil also increased hepatic LDL receptor activity; however, since the rate of LDL production also increased, plasma LDL-cholesterol levels remained essentially unchanged. Hydrogenated coconut oil had no effect on LDL receptor activity but increased the rate of LDL-cholesterol production causing plasma LDL-cholesterol levels to increase 46%. Dietary fish oil had no effect on the receptor-dependent transport of asialofetuin by the liver, suggesting that the effect of fish oil on hepatic LDL receptor activity was specific and not due to a generalized alteration in the physical properties of hepatic membranes. Finally, dietary fish oil increased hepatic cholesteryl ester levels and suppressed hepatic cholesterol synthesis rates, suggesting that the up-regulation of hepatic LDL receptor activity in these animals was not simply a response to diminished cholesterol availability in the liver. PMID:2760200

Nonpharmacological lipoprotein apheresis reduces arterial inflammation in familial hypercholesterolemia

NARCIS (Netherlands)

van Wijk, Diederik F.; Sjouke, Barbara; Figueroa, Amparo; Emami, Hamed; van der Valk, Fleur M.; MacNabb, Megan H.; Hemphill, Linda C.; Schulte, Dominik M.; Koopman, Marion G.; Lobatto, Mark E.; Verberne, Hein J.; Fayad, Zahi A.; Kastelein, John J. P.; Mulder, Willem J. M.; Hovingh, G. Kees; Tawakol, Ahmed; Stroes, Erik S. G.

2014-01-01

Patients with familial hypercholesterolemia (FH) are characterized by elevated atherogenic lipoprotein particles, predominantly low-density lipoprotein cholesterol (LDL-C), which is associated with accelerated atherogenesis and increased cardiovascular risk. This study used (18)F-fluorodeoxyglucose

Experimental hypothyroidism modulates the expression of the low density lipoprotein receptor by the liver

International Nuclear Information System (INIS)

Scarabottolo, Lia; Trezzi, Ermanno; Roma, Paola; Catapano, A.L.

1986-01-01

The effect of exprimental hypothyroidism of the catabolism of plasma lipoproteins and on the expression of low density lipoprotein receptors by the liver was investigated in rats made hypothyroid by surgery. The animals developed mild hypercholesterolemia, mainly due to an increase of plasma low density lipoprotein, while other lipoprotein classes were only marginally affected. Kinetic studies using ( 125 I)LDL indicated that a decreased fractional catabolic rate of the lipoprotein was responsible for this finding in agreement with the in vitro observation of a reduced binding of lipoproteins to liver membranes from hyperthyroid rats and with the demonstrations, by ligand blotting analysis, of a decreasd expression of lipoprotein receptors in liver membranes. These data suggest that hypothyroidism affects lipoprotein distribution also by decreasing the catabolism of low density lipoproteins by the liver (author)

The Journey of Lipoproteins Through the Cell: One Birthplace, Multiple Destinations.

Science.gov (United States)

Szewczyk, J; Collet, J-F

2016-01-01

Bacterial lipoproteins are a very diverse group of proteins characterized by the presence of an N-terminal lipid moiety that serves as a membrane anchor. Lipoproteins have a wide variety of crucial functions, ranging from envelope biogenesis to stress response. In Gram-negative bacteria, lipoproteins can be targeted to various destinations in the cell, including the periplasmic side of the cytoplasmic or outer membrane, the cell surface or the external milieu. The sorting mechanisms have been studied in detail in Escherichia coli, but exceptions to the rules established in this model bacterium exist in other bacteria. In this chapter, we will present the current knowledge on lipoprotein sorting in the cell. Our particular focus will be on the surface-exposed lipoproteins that appear to be much more common than previously assumed. We will discuss the different targeting strategies, provide numerous examples of surface-exposed lipoproteins and discuss the techniques used to assess their surface exposure. © 2016 Elsevier Ltd All rights reserved.

Redefining the essential trafficking pathway for outer membrane lipoproteins

OpenAIRE

Grabowicz, Marcin; Silhavy, Thomas J.

2017-01-01

In Gram-negative bacteria, most lipoproteins synthesized in the inner membrane (IM) are trafficked to the outer membrane (OM). The Lol pathway is the trafficking paradigm: LolCDE releases lipoproteins from the IM; LolA shuttles them between membranes to LolB in the OM. Several OM lipoproteins are essential for viability. In apparent concordance, the Lol proteins are each essential in wild-type cells. However, we show that Escherichia coli grows well without LolA and LolB in the absence of one...

Interaction of Mycoplasma hominis PG21 with Human Dendritic Cells: Interleukin-23-Inducing Mycoplasmal Lipoproteins and Inflammasome Activation of the Cell.

Science.gov (United States)

Goret, J; Béven, L; Faustin, B; Contin-Bordes, C; Le Roy, C; Claverol, S; Renaudin, H; Bébéar, C; Pereyre, S

2017-08-01

Mycoplasma hominis lacks a cell wall, and lipoproteins anchored to the extracellular side of the plasma membrane are in direct contact with the host components. A Triton X-114 extract of M. hominis enriched with lipoproteins was shown to stimulate the production of interleukin-23 (IL-23) by human dendritic cells (hDCs). The inflammasome activation of the host cell has never been reported upon M. hominis infection. We studied here the interaction between M. hominis PG21 and hDCs by analyzing both the inflammation-inducing mycoplasmal lipoproteins and the inflammasome activation of the host cell. IL-23-inducing lipoproteins were determined using a sequential extraction strategy with two nondenaturing detergents, Sarkosyl and Triton X-114, followed by SDS-PAGE separation and mass spectrometry identification. The activation of the hDC inflammasome was assessed using PCR array and enzyme-linked immunosorbent assay (ELISA). We defined a list of 24 lipoproteins that could induce the secretion of IL-23 by hDCs, 5 with a molecular mass between 20 and 35 kDa and 19 with a molecular mass between 40 and 100 kDa. Among them, lipoprotein MHO_4720 was identified as potentially bioactive, and a synthetic lipopeptide corresponding to the N-terminal part of the lipoprotein was subsequently shown to induce IL-23 release by hDCs. Regarding the hDC innate immune response, inflammasome activation with caspase-dependent production of IL-1β was observed. After 24 h of coincubation of hDCs with M. homini s, downregulation of the NLRP3-encoding gene and of the adaptor PYCARD-encoding gene was noticed. Overall, this study provides insight into both protagonists of the interaction of M. hominis and hDCs. IMPORTANCE Mycoplasma hominis is a human urogenital pathogen involved in gynecologic and opportunistic infections. M. hominis lacks a cell wall, and its membrane contains many lipoproteins that are anchored to the extracellular side of the plasma membrane. In the present study, we focused on

Effect of I125 on oxidation behavior of lipoprotein subpopulations

International Nuclear Information System (INIS)

Majtenyi, S.

2002-07-01

Lipoproteins play a central role in lipid metabolism. They serve as a transport vehicle for cholesterol and triglycerides keeping them in plasma in solution. Lipoproteins are characterized by the content of specific apoproteins and differences in the hydrated density ranges. Moreover, they are distinguished by electrophoretic mobility and other characteristics as high and low-density lipoproteins, respectively lipoprotein (a). More specifically, HDL is classified into HDL 2 and HDL 3 . In atherogenesis, lipoproteins are considered to play a key-role. Oxidatively modified LDL is selectively taken up via scavenger receptors of the macrophage-monocyte system. These cells are transformed into foam cells promoting atherogenesis in vessels in the subendothelial space. Oxidized HDL essentially appears to loose its protective effects on LDL and its beneficial function in reverse cholesterol transport. Thus, it turns proatherogenic. The effects various species of free radicals exert on lipoproteins are the reason for this oxidative modification. Thyroid function also influences lipoproteins in a complex manner. Based on their hydrated density ranges, lipoprotein subpopulations were fractionated and isolated via isopycnic density gradient ultracentrifugation. After investigation of the general oxidation behavior, initiated by addition of CuSO 4 to the isolated samples of HDL 3 , HDL 2 , LDL and Lp(a), the influence of different activities of radioiodine-125 on the kinetics of the formation of conjugated dienes was assessed. This was achieved by coincubation of plasma with I 125 . The spectrophotometrical measurement of the concentration of conjugated dienes in the course of CuSO 4 -induced lipid peroxidation leads to measurable changes in absorption at 234 nm. These changes in absorption over time result in a characteristically shaped curve graphically plotted. The shape of these curves mirrors different indicators of lipid peroxidation. Therefrom lag time, maximal

The use of transgenic animals to study lipoprotein metabolism

Energy Technology Data Exchange (ETDEWEB)

Rubin, E.M.; Plump, A.S.

1993-12-01

The application of transgenic technology to lipoprotein metabolism and atherosclerosis was first reported in 1988. Today, a large percentage of the genes involved in lipoprotein metabolism have been overexpressed in mice, and a substantial number of these same genes have been disrupted by homologous recombination in embryonic stem (ES) cells. The utility of animal models of lipoprotein metabolism and atherosclerosis is far-reaching given the complex nature of these systems. There are at least 17 known genes directly involved in lipoprotein metabolism and likely dozens more may be involved. This massive network of interacting factors has necessitated the development of in vivo systems which can be subject to genetic manipulation. The power of overexpression is obvious: elucidating function in a relatively controlled genetic environment in which the whole system is present and operational. The not-so-obvious problem with transgenics is ``background,`` or for purposes of the current discussion, the mouse`s own lipoprotein system. With the advent of gene knockout, we have been given the ability to overcome ``background.`` By recreating the genetic complement of the mouse we can alter a system in essentially any manner desired. As unique tools, and in combination with one another, the overexpression of foreign genes and the targeted disruption or alteration of endogenous genes has already and will continue to offer a wealth of information on the biology of lipoprotein metabolism and its effect on atherosclerosis susceptibility.

Elevated Lipoprotein(A Impairs Platelet Radiolabeling Yield

Directory of Open Access Journals (Sweden)

Susanne Granegger

2015-02-01

Full Text Available Objectives: Platelet radiolabeling in clinical routine usually results in labeling efficiencies (LE above 80%. A variety of risk factors and clinical conditions are known to impair platelet labeling yield, among them elevated triglycerides and low-density lipoproteins. The potential influence of lipoprotein(a (Lp(a, an atherogenic lipoprotein particle containing a kringle subunit, which is widely found in the proteins of fibrinolysis pathway, has never been studied. Normal Lp(a levels range below 30 mg/ dl. The exact prevalence of elevated Lp(a is unknown, most likely ranging below 10%. Even more rare is an isolated elevation despite an otherwise normal lipoprotein profile. Methods: We examined the role of isolated elevated Lp(a (> 50 mg/dl, ranging up to 440 mg/dl compared to patients with normal lipid profile. Platelets were radiolabeled with in-111-oxine at 37 °C for 5 minutes using ISORBE-consensus methodology. Results: The findings indicate that already at levels below 100 mg/dl Lp(a decreases LE. LE assessment after cross-incubation of hyper-Lp(a platelets with normal Lp(a plasma and vice versa reveals that platelets rather than the plasmatic environment are responsible for the deterioration of labeling yield. This behavior already has been reported for elevated low-density lipoproteins. Apparently, the quantitative influence of LDL and Lp(a/mg is comparable. Plotting the sum of LDL and Lp(a versus LE reveals a clear significant negative correlation. Conclusion: As extremely elevated Lp(a, particularly above 150 mg/dl, may significantly impair labeling results. We therefore recommend to include extremely elevated Lp(a into the list of parameters, which should be known before performing radiolabeling of human platelets.

Serum lipid and lipoprotein concentrations following exposure to ozone

Energy Technology Data Exchange (ETDEWEB)

Vaughan, W J; Adamson, G L; Lindgren, F T; Schooley, J.C.

1984-07-01

The effects of exposure to ozone (O/sub 3/) on concentrations of serum lipids and lipoproteins were investigated. Male and female guinea pigs were exposed to O/sub 3/ at 1 ppm for two weeks. Serum concentrations of cholesterol, triglycerides, low density (LDL) and very low density (VLDL) lipoproteins were elevated after O/sub 3/ exposure, particularly in males. During O/sub 3/ exposure the food intake per day decreased (for a constant body weight), suggesting that metabolic rate and possibly basal metabolic rate was lower. Lung wet weights increased during O/sub 3/ exposure by 87% for males and 45% for females. When individual lung weight/body weight ratios were correlated with cholesterol and LDL values from the same animal, a high correlation is found for males (r . 0.81, P less than 0.05), suggesting that there may be a relationship between lipoprotein elevations and lung damage for males. Because elevated concentrations of lipids and lipoproteins in humans increase the risk of coronary heart disease (CHD), the lipoprotein results suggest that an epidemiological study of the incidence of CHD with metropolitan O/sub 3/ levels may be warranted.

PCSK9 and triglyceride-rich lipoprotein metabolism.

Science.gov (United States)

Druce, I; Abujrad, H; Ooi, T C

2015-07-20

Pro-protein convertase subtilisin-kexin 9 (PCSK9) is known to affect low-density lipoprotein (LDL) metabolism, but there are indications from several lines of research that it may also influence the metabolism of other lipoproteins, especially triglyceride-rich lipoproteins (TRL). This review summarizes the current data on this possible role of PCSK9. A link between PCSK9 and TRL has been suggested through the demonstration of (1) a correlation between plasma PCSK9 and triglyceride (TG) levels in health and disease, (2) a correlation between plasma PCSK9 and markers of carbohydrate metabolism, which is closely related to TG metabolism, (3) an effect of TG-lowering fibrate therapy on plasma PCSK9 levels, (4) an effect of PCSK9 on postprandial lipemia, (5) an effect of PCSK9 on adipose tissue biology, (6) an effect of PCSK9 on apolipoprotein B production from the liver and intestines, (7) an effect of PCSK9 on receptors other than low density lipoprotein receptor (LDLR) that are involved in TRL metabolism, and (8) an effect of anti-PCSK9 therapy on serum TG levels. The underlying mechanisms are unclear but starting to emerge. © 2015 the Journal of Biomedical Research. All rights reserved.

Secretion of bacterial lipoproteins: through the cytoplasmic membrane, the periplasm and beyond.

Science.gov (United States)

Zückert, Wolfram R

2014-08-01

Bacterial lipoproteins are peripherally anchored membrane proteins that play a variety of roles in bacterial physiology and virulence in monoderm (single membrane-enveloped, e.g., gram-positive) and diderm (double membrane-enveloped, e.g., gram-negative) bacteria. After export of prolipoproteins through the cytoplasmic membrane, which occurs predominantly but not exclusively via the general secretory or Sec pathway, the proteins are lipid-modified at the cytoplasmic membrane in a multistep process that involves sequential modification of a cysteine residue and cleavage of the signal peptide by the signal II peptidase Lsp. In both monoderms and diderms, signal peptide processing is preceded by acylation with a diacylglycerol through preprolipoprotein diacylglycerol transferase (Lgt). In diderms but also some monoderms, lipoproteins are further modified with a third acyl chain through lipoprotein N-acyl transferase (Lnt). Fully modified lipoproteins that are destined to be anchored in the inner leaflet of the outer membrane (OM) are selected, transported and inserted by the Lol (lipoprotein outer membrane localization) pathway machinery, which consists of the inner-membrane (IM) ABC transporter-like LolCDE complex, the periplasmic LolA chaperone and the OM LolB lipoprotein receptor. Retention of lipoproteins in the cytoplasmic membrane results from Lol avoidance signals that were originally described as the "+2 rule". Surface localization of lipoproteins in diderms is rare in most bacteria, with the exception of several spirochetal species. Type 2 (T2SS) and type 5 (T5SS) secretion systems are involved in secretion of specific surface lipoproteins of γ-proteobacteria. In the model spirochete Borrelia burgdorferi, surface lipoprotein secretion does not follow established sorting rules, but remains dependent on N-terminal peptide sequences. Secretion through the outer membrane requires maintenance of lipoproteins in a translocation-competent unfolded conformation

Large-scale preparation of the homogeneous LolA–lipoprotein complex and efficient in vitro transfer of lipoproteins to the outer membrane in a LolB-dependent manner

OpenAIRE

Watanabe, Shoji; Oguchi, Yuki; Yokota, Naoko; Tokuda, Hajime

2007-01-01

An ATP-binding cassette transporter LolCDE complex of Escherichia coli releases lipoproteins destined to the outer membrane from the inner membrane as a complex with a periplasmic chaperone, LolA. Interaction of the LolA–lipoprotein complex with an outer membrane receptor, LolB, then causes localization of lipoproteins to the outer membrane. As far as examined, formation of the LolA–lipoprotein complex strictly depends on ATP hydrolysis by the LolCDE complex in the presence of LolA. It has be...

Plasma Cholesteryl Ester Transfer, But Not Cholesterol Esterification, Is Related to Lipoprotein-Associated Phospholipase A(2) : Possible Contribution to an Atherogenic Lipoprotein Profile

NARCIS (Netherlands)

Dullaart, Robin P. F.; Constantinides, Alexander; Perton, Frank G.; van Leeuwen, Jeroen J. J.; van Pelt, Joost L.; de Vries, Rindert; van Tol, Arie

Context: Plasma lipoprotein-associated phospholipase A(2) (Lp-PLA(2)) predicts incident cardiovascular disease and is associated preferentially with negatively charged apolipoprotein B-containing lipoproteins. The plasma cholesteryl ester transfer (CET) process, which contributes to low high-density

A Phospholipidomic Analysis of All Defined Human Plasma Lipoproteins

NARCIS (Netherlands)

Dashti, Monireh; Kulik, Willem; Hoek, Frans; Veerman, Enno C.; Peppelenbosch, Maikel P.; Rezaee, Farhad

2011-01-01

Since plasma lipoproteins contain both protein and phospholipid components, either may be involved in processes such as atherosclerosis. In this study the identification of plasma lipoprotein-associated phospholipids, which is essential for understanding these processes at the molecular level, are

A phospholipidomic analysis of all defined human plasma lipoproteins

NARCIS (Netherlands)

Dashti, Monireh; Kulik, Willem; Hoek, Frans; Veerman, Enno C.; Peppelenbosch, Maikel P.; Rezaee, Farhad

2011-01-01

Since plasma lipoproteins contain both protein and phospholipid components, either may be involved in processes such as atherosclerosis. In this study the identification of plasma lipoprotein-associated phospholipids, which is essential for understanding these processes at the molecular level, are

High-Density Lipoprotein Reduction Differentially Modulates to Classical and Nonclassical Monocyte Subpopulations in Metabolic Syndrome Patients and in LPS-Stimulated Primary Human Monocytes In Vitro

Science.gov (United States)

Grün, Johanna L.; Manjarrez-Reyna, Aaron N.; Gómez-Arauz, Angélica Y.; Leon-Cabrera, Sonia; Bueno-Hernández, Nallely; Islas-Andrade, Sergio

2018-01-01

The effect of metabolic syndrome on human monocyte subpopulations has not yet been studied. Our main goal was to examine monocyte subpopulations in metabolic syndrome patients, while also identifying the risk factors that could directly influence these cells. Eighty-six subjects were divided into metabolic syndrome patients and controls. Monocyte subpopulations were quantified by flow cytometry, and interleukin- (IL-) 1β secretion levels were measured by ELISA. Primary human monocytes were cultured in low or elevated concentrations of high-density lipoprotein (HDL) and stimulated with lipopolysaccharide (LPS). The nonclassical monocyte (NCM) percentage was significantly increased in metabolic syndrome patients as compared to controls, whereas classical monocytes (CM) were reduced. Among all metabolic syndrome risk factors, HDL reduction exhibited the most important correlation with monocyte subpopulations and then was studied in vitro. Low HDL concentration reduced the CM percentage, whereas it increased the NCM percentage and IL-1β secretion in LPS-treated monocytes. The LPS effect was abolished when monocytes were cultured in elevated HDL concentrations. Concurring with in vitro results, IL-1β serum values significantly increased in metabolic syndrome patients with low HDL levels as compared to metabolic syndrome patients without HDL reduction. Our data demonstrate that HDL directly modulates monocyte subpopulations in metabolic syndrome. PMID:29850624

High-Density Lipoprotein Reduction Differentially Modulates to Classical and Nonclassical Monocyte Subpopulations in Metabolic Syndrome Patients and in LPS-Stimulated Primary Human Monocytes In Vitro

Directory of Open Access Journals (Sweden)

Johanna L. Grün

2018-01-01

Full Text Available The effect of metabolic syndrome on human monocyte subpopulations has not yet been studied. Our main goal was to examine monocyte subpopulations in metabolic syndrome patients, while also identifying the risk factors that could directly influence these cells. Eighty-six subjects were divided into metabolic syndrome patients and controls. Monocyte subpopulations were quantified by flow cytometry, and interleukin- (IL- 1β secretion levels were measured by ELISA. Primary human monocytes were cultured in low or elevated concentrations of high-density lipoprotein (HDL and stimulated with lipopolysaccharide (LPS. The nonclassical monocyte (NCM percentage was significantly increased in metabolic syndrome patients as compared to controls, whereas classical monocytes (CM were reduced. Among all metabolic syndrome risk factors, HDL reduction exhibited the most important correlation with monocyte subpopulations and then was studied in vitro. Low HDL concentration reduced the CM percentage, whereas it increased the NCM percentage and IL-1β secretion in LPS-treated monocytes. The LPS effect was abolished when monocytes were cultured in elevated HDL concentrations. Concurring with in vitro results, IL-1β serum values significantly increased in metabolic syndrome patients with low HDL levels as compared to metabolic syndrome patients without HDL reduction. Our data demonstrate that HDL directly modulates monocyte subpopulations in metabolic syndrome.

Surface-Exposed Lipoproteins: An Emerging Secretion Phenomenon in Gram-Negative Bacteria.

Science.gov (United States)

Wilson, Marlena M; Bernstein, Harris D

2016-03-01

Bacterial lipoproteins are hydrophilic proteins that are anchored to a cell membrane by N-terminally linked fatty acids. It is widely believed that nearly all lipoproteins produced by Gram-negative bacteria are either retained in the inner membrane (IM) or transferred to the inner leaflet of the outer membrane (OM). Lipoproteins that are exposed on the cell surface have also been reported but are generally considered to be rare. Results from a variety of recent studies, however, now suggest that the prevalence of surface-exposed lipoproteins has been underestimated. In this review we describe the evidence that the surface exposure of lipoproteins in Gram-negative bacteria is a widespread phenomenon and discuss possible mechanisms by which these proteins might be transported across the OM. Published by Elsevier Ltd.

High density lipoprotein (HDL)-associated sphingosine 1-phosphate (S1P) inhibits macrophage apoptosis by stimulating STAT3 activity and survivin expression

DEFF Research Database (Denmark)

Feuerborn, Renata; Becker, Susen; Potì, Francesco

2017-01-01

BACKGROUND AND AIMS: Macrophage apoptosis is critically involved in atherosclerosis. We here examined the effect of anti-atherogenic high density lipoprotein (HDL) and its component sphingosine-1-phosphate (S1P) on apoptosis in RAW264.7 murine macrophages. METHODS: Mitochondrial or endoplasmic re...

Cholesterol transfer from normal and atherogenic low density lipoproteins to Mycoplasma membranes

International Nuclear Information System (INIS)

Mitschelen, J.J.; St Clair, R.W.; Hester, S.H.

1981-01-01

The purpose of this study was to determine whether the free cholesterol of hypercholesterolemic low density lipoprotein from cholesterol-fed nonhuman primates has a greater potential for surface transfer to cell membranes than does the free cholesterol of normal low density lipoprotein. The low density lipoproteins were isolated from normal and hypercholesterolemic rhesus and cynomolgus monkeys, incubated with membranes from Acholeplasma laidlawii, a mycoplasma species devoid of cholesterol in its membranes, and the mass transfer of free cholesterol determined by measuring membrane cholesterol content. Since these membranes neither synthesize nor esterify cholesterol, nor degrade the protein or cholesterol ester moieties of low density lipoprotein, they are an ideal model with which to study differences in the cholesterol transfer potential of low density lipoprotein independent of the uptake of the intact low density lipoprotein particle. These studies indicate that, even though there are marked differences in the cholesterol composition of normal and hypercholesterolemic low density lipoproteins, this does not result in a greater chemical potential for surface transfer of free cholesterol. Consequently, if a difference in the surface transfer of free cholesterol is responsible for the enhanced ability of hypercholesterolemic low density lipoprotein to promote cellular cholesterol accumulation and, perhaps, also atherosclerosis, it must be the result of differences in the interaction to the hypercholesterolemic low density lipoprotein with the more complicated mammalian cell membranes, rather than differences in the chemical potential for cholesterol transfer

Lipoproteins in Drosophila melanogaster—Assembly, Function, and Influence on Tissue Lipid Composition

Science.gov (United States)

Palm, Wilhelm; Sampaio, Julio L.; Brankatschk, Marko; Carvalho, Maria; Mahmoud, Ali; Shevchenko, Andrej; Eaton, Suzanne

2012-01-01

Interorgan lipid transport occurs via lipoproteins, and altered lipoprotein levels correlate with metabolic disease. However, precisely how lipoproteins affect tissue lipid composition has not been comprehensively analyzed. Here, we identify the major lipoproteins of Drosophila melanogaster and use genetics and mass spectrometry to study their assembly, interorgan trafficking, and influence on tissue lipids. The apoB-family lipoprotein Lipophorin (Lpp) is the major hemolymph lipid carrier. It is produced as a phospholipid-rich particle by the fat body, and its secretion requires Microsomal Triglyceride Transfer Protein (MTP). Lpp acquires sterols and most diacylglycerol (DAG) at the gut via Lipid Transfer Particle (LTP), another fat body-derived apoB-family lipoprotein. The gut, like the fat body, is a lipogenic organ, incorporating both de novo–synthesized and dietary fatty acids into DAG for export. We identify distinct requirements for LTP and Lpp-dependent lipid mobilization in contributing to the neutral and polar lipid composition of the brain and wing imaginal disc. These studies define major routes of interorgan lipid transport in Drosophila and uncover surprising tissue-specific differences in lipoprotein lipid utilization. PMID:22844248

TRIIODOTHYRONINE RAPIDLY LOWERS PLASMA-LIPOPROTEIN (A) IN HYPOTHYROID SUBJECTS

NARCIS (Netherlands)

DULLAART, RPF; VANDOORMAAL, JJ; HOOGENBERG, K; SLUITER, WJ

Background: Increases in plasma low-density-lipoprotein (LDL) cholesterol and apolipoprotein B (apo-B) are well known in primary hypothyroidism, but it is uncertain whether thyroid dysfunction is associated with elevated levels of the atherogenic lipoprotein (a) (Lp(a)). Methods: The effect of

Prediction of lipoprotein signal peptides in Gram-negative bacteria

DEFF Research Database (Denmark)

Juncker, Agnieszka; Willenbrock, Hanni; Von Heijne, G.

2003-01-01

A method to predict lipoprotein signal peptides in Gram-negative Eubacteria, LipoP, has been developed. The hidden Markov model (HMM) was able to distinguish between lipoproteins (SPaseII-cleaved proteins), SPaseI-cleaved proteins, cytoplasmic proteins, and transmembrane proteins. This predictor ...

Low density lipoproteins mediated nanoplatforms for cancer targeting

International Nuclear Information System (INIS)

Jain, Anupriya; Jain, Keerti; Kesharwani, Prashant; Jain, Narendra K.

2013-01-01

Chemotherapy is a foremost remedial approach for the treatment of localized and metastasized tumors. In order to explore new treatment modalities for cancer, it is important to identify qualitative or quantitative differences in metabolic processes between normal and malignant cells. One such difference may be that of increased receptor-mediated cellular uptake of low density lipoproteins (LDLs) by cancer cells. Lipoproteins in general and specifically LDL are ideal candidates for loading and delivering cancer therapeutic and diagnostic agents due to their biocompatibility. By mimicking the endogenous shape and structure of lipoproteins, the reconstituted lipoproteins can remain in circulation for an extended period of time, while largely evading the reticuloendothelial cells in the body’s defenses. In this account, we review the field of low density inspired nanoparticles in relation to the delivery of cancer imaging and therapeutic agents. LDL has instinctive cancer targeting potential and has been used to incorporate various lipophillic molecules to transport them to tumors. Nature’s method of rerouting LDL provides a strategy to extend the cancer targeting potential of lipoproteins far off its constricted purview. In this review, we have discussed the various aspects of LDL including its role in cancer imaging and chemotherapy in retrospect and prospect and current efforts aimed to further improve the delivery efficacy of LDL–drug complexes with reduced chances of drug resistance leading to optimal drug delivery. This review provides a strong support for the concept of using LDL as a drug carrier

Low density lipoproteins mediated nanoplatforms for cancer targeting

Energy Technology Data Exchange (ETDEWEB)

Jain, Anupriya; Jain, Keerti; Kesharwani, Prashant, E-mail: prashant_pharmacy04@rediffmail.com; Jain, Narendra K., E-mail: jnarendr@yahoo.co.in [Dr. H. S. Gour University, Pharmaceutics Research Laboratory, Department of Pharmaceutical Sciences (India)

2013-09-15

Chemotherapy is a foremost remedial approach for the treatment of localized and metastasized tumors. In order to explore new treatment modalities for cancer, it is important to identify qualitative or quantitative differences in metabolic processes between normal and malignant cells. One such difference may be that of increased receptor-mediated cellular uptake of low density lipoproteins (LDLs) by cancer cells. Lipoproteins in general and specifically LDL are ideal candidates for loading and delivering cancer therapeutic and diagnostic agents due to their biocompatibility. By mimicking the endogenous shape and structure of lipoproteins, the reconstituted lipoproteins can remain in circulation for an extended period of time, while largely evading the reticuloendothelial cells in the body's defenses. In this account, we review the field of low density inspired nanoparticles in relation to the delivery of cancer imaging and therapeutic agents. LDL has instinctive cancer targeting potential and has been used to incorporate various lipophillic molecules to transport them to tumors. Nature's method of rerouting LDL provides a strategy to extend the cancer targeting potential of lipoproteins far off its constricted purview. In this review, we have discussed the various aspects of LDL including its role in cancer imaging and chemotherapy in retrospect and prospect and current efforts aimed to further improve the delivery efficacy of LDL-drug complexes with reduced chances of drug resistance leading to optimal drug delivery. This review provides a strong support for the concept of using LDL as a drug carrier.

Low density lipoproteins mediated nanoplatforms for cancer targeting

Science.gov (United States)

Jain, Anupriya; Jain, Keerti; Kesharwani, Prashant; Jain, Narendra K.

2013-09-01

Chemotherapy is a foremost remedial approach for the treatment of localized and metastasized tumors. In order to explore new treatment modalities for cancer, it is important to identify qualitative or quantitative differences in metabolic processes between normal and malignant cells. One such difference may be that of increased receptor-mediated cellular uptake of low density lipoproteins (LDLs) by cancer cells. Lipoproteins in general and specifically LDL are ideal candidates for loading and delivering cancer therapeutic and diagnostic agents due to their biocompatibility. By mimicking the endogenous shape and structure of lipoproteins, the reconstituted lipoproteins can remain in circulation for an extended period of time, while largely evading the reticuloendothelial cells in the body's defenses. In this account, we review the field of low density inspired nanoparticles in relation to the delivery of cancer imaging and therapeutic agents. LDL has instinctive cancer targeting potential and has been used to incorporate various lipophillic molecules to transport them to tumors. Nature's method of rerouting LDL provides a strategy to extend the cancer targeting potential of lipoproteins far off its constricted purview. In this review, we have discussed the various aspects of LDL including its role in cancer imaging and chemotherapy in retrospect and prospect and current efforts aimed to further improve the delivery efficacy of LDL-drug complexes with reduced chances of drug resistance leading to optimal drug delivery. This review provides a strong support for the concept of using LDL as a drug carrier.

Influence of medium components on the expression of recombinant lipoproteins in Escherichia coli.

Science.gov (United States)

Tseng, Chi-Ling; Leng, Chih-Hsiang

2012-02-01

Bacterial lipoproteins are crucial antigens for protective immunity against bacterial pathogens. Expression of exogenous lipoproteins in Escherichia coli at high levels is thought to be an extremely difficult endeavor because it frequently results in incomplete or absent lipid modification. Previously, we identified a fusion sequence (D1) from a Neisseria meningitidis lipoprotein that induced a non-lipidated protein, E3 (the domain III of the dengue virus envelope protein), to become lipidated. However, without optimizing the growth conditions, some of the D1-fusion proteins were not lipidated. Here, we report the influence of medium components on the expression of recombinant lipoproteins in E. coli. For high-level expression of mature lipoproteins in the C43 (DE3) strain, M9 medium was better than M63 and the rich medium. Furthermore, we analyzed the influence of other media factors (including nitrogen and carbon sources, phosphate, ferrous ions, calcium, magnesium, and pH) on the levels of lipoprotein expression. The results showed that excess nitrogen sources and phosphate in M9 medium could increase the amount of immature lipoproteins, and glucose was a better carbon source than glycerol for expressing mature lipoproteins. We also found that lipoproteins tended to be completely processed in the alkaline environment, even in the nutrient-rich medium. Additional constructs expressing different immunogens or lipid signal peptides as targets were also utilized, demonstrating that these targets could be expressed as completely mature lipoproteins in the M9 medium but not in the rich medium. Our results provide the useful information for expressing mature exogenous lipoproteins in E. coli.

Mycobacterium tuberculosis lipoproteins in virulence and immunity - fighting with a double-edged sword.

Science.gov (United States)

Becker, Katja; Sander, Peter

2016-11-01

Bacterial lipoproteins are secreted membrane-anchored proteins characterized by a lipobox motif. This lipobox motif directs post-translational modifications at the conserved cysteine through the consecutive action of three enzymes: Lgt, LspA and Lnt, which results in di- or triacylated forms. Lipoproteins are abundant in all bacteria including Mycobacterium tuberculosis and often involved in virulence and immunoregulatory processes. On the one hand, disruption of the biosynthesis pathway of lipoproteins leads to attenuation of M. tuberculosis in vivo, and mycobacteria deficient for certain lipoproteins have been assessed as attenuated live vaccine candidates. On the other hand, several mycobacterial lipoproteins form immunodominant antigens which promote an immune response. Some of these have been explored in DNA or subunit vaccination approaches against tuberculosis. The immune recognition of specific lipoproteins, however, might also benefit long-term survival of M. tuberculosis through immune modulation, while others induce protective responses. Exploiting lipoproteins as vaccines is thus a complex matter which requires deliberative investigation. The dual role of lipoproteins in the immunity to and pathogenicity of mycobacteria is discussed here. © 2016 Federation of European Biochemical Societies.

The Impact of Cardiorespiratory Fitness on Age-Related Lipids and Lipoproteins

Science.gov (United States)

Park, Yong-Moon Mark; Sui, Xuemei; Liu, Junxiu; Zhou, Haiming; Kokkinos, Peter F.; Lavie, Carl J.; Hardin, James W.; Blair, Steven N.

2015-01-01

Background Evidence on the effect of cardiorespiratory fitness (CRF) on age-related longitudinal changes of lipids and lipoproteins is scarce. Objectives This study sought to assess the longitudinal, aging trajectory of lipids and lipoproteins for the life course in adults, and to determine whether CRF modifies the age-associated trajectory of lipids and lipoproteins. Methods Data came from 11,418 men, 20 to 90 years of age, without known high cholesterol, high triglycerides, cardiovascular disease, and cancer at baseline and during follow-up from the Aerobics Center Longitudinal Study. There were 43,821 observations spanning 2 to 25 (mean 3.5) health examinations between 1970 and 2006. CRF was quantified by a maximal treadmill exercise test. Marginal models using generalized estimating equations were applied. Results Total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), triglycerides (TG), and non-high-density lipoprotein cholesterol (non-HDL-C) presented similar inverted U-shaped quadratic trajectories with aging: gradual increases were noted until the mid-40s to early 50s, with subsequent declines (all p lipoproteins in young to middle-aged men than in older men. Conclusions Our investigation reveals a differential trajectory of lipids and lipoproteins with aging according to CRF in healthy men, and suggests that promoting increased CRF levels may help delay the development of dyslipidemia. PMID:25975472

The effect of cardiorespiratory fitness on age-related lipids and lipoproteins.

Science.gov (United States)

Park, Yong-Moon Mark; Sui, Xuemei; Liu, Junxiu; Zhou, Haiming; Kokkinos, Peter F; Lavie, Carl J; Hardin, James W; Blair, Steven N

2015-05-19

Evidence on the effect of cardiorespiratory fitness (CRF) on age-related longitudinal changes of lipids and lipoproteins is scarce. This study sought to assess the longitudinal aging trajectory of lipids and lipoproteins for the life course in adults and to determine whether CRF modifies the age-associated trajectory of lipids and lipoproteins. Data came from 11,418 men, 20 to 90 years of age, without known high cholesterol, high triglycerides, cardiovascular disease, and cancer at baseline and during follow-up from the Aerobics Center Longitudinal Study. There were 43,821 observations spanning 2 to 25 health examinations (mean 3.5 examinations) between 1970 and 2006. CRF was quantified by a maximal treadmill exercise test. Marginal models using generalized estimating equations were applied. Total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), triglycerides, and non-high-density lipoprotein cholesterol (non-HDL-C) presented similar inverted U-shaped quadratic trajectories with aging: gradual increases were noted until age mid-40s to early 50s, with subsequent declines (all p lipoproteins in young to middle-age men than in older men. Our investigation reveals a differential trajectory of lipids and lipoproteins with aging according to CRF in healthy men and suggests that promoting increased CRF levels may help delay the development of dyslipidemia. Copyright © 2015 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

Lipoprotein receptors in cultured bovine endothelial cells

International Nuclear Information System (INIS)

Struempfer, A.E.M.

1983-07-01

In this study, receptors that may be involved in the uptake of low density lipoproteins (LDL) and low density lipoproteins which have been modified by acetylation (AcLDL), were characterized. Aortic epithelial cells were used and a cell culture system which closely resembled the in vivo monolayer was established. Endothelial cell and lipoprotein interactions were examined by incubating the cells with 125 l-labelled lipoproteins under various conditions. The receptor affinity of bovine aortic endothelial cells was higher for AcLDL than that for LDL. Competition studies demonstrated that there were two distinct receptors for LDL and AcLDL on the endothelial cells. AcLDL did not compete with LDL for the LDL receptor, and conversely LDL did not compete with AcLDL for the AcLDL receptor. The receptor activities for LDL and AcLDL were examined as a function of culture age. Whereas the LDL receptor could be regulated, the AcLDL receptor was not as susceptible to regulation. Upon exposing endothelial cells for 72 h to either LDL or AcLDL, it was found that the total amount of cellular cholesterol increased by about 50%. However, the increase of total cholesterol was largely in the form of free cholesterol. This is in contrast to macrophages, where the increase in total cholesterol upon exposure to AcLDL is largely in the form cholesteryl esters

Lipoproteins tethered dendrimeric nanoconstructs for effective targeting to cancer cells

Science.gov (United States)

Jain, Anupriya; Jain, Keerti; Mehra, Neelesh Kumar; Jain, N. K.

2013-10-01

In the present investigation, poly (propylene imine) dendrimers up to fifth generation (PPI G5.0) were synthesized using ethylene diamine and acrylonitrile. Lipoproteins (high-density lipoprotein; HDL and low-density lipoprotein; LDL) were isolated from human plasma by discontinuous density gradient ultracentrifugation, characterized and tethered to G5.0 PPI dendrimers to construct LDL- and HDL-conjugated dendrimeric nanoconstructs for tumor-specific delivery of docetaxel. Developed formulations showed sustained release characteristics in in vitro drug release and in vivo pharmacokinetic studies. The cancer targeting potential of lipoprotein coupled dendrimers was investigated by ex vivo cytotoxicity and cell uptake studies using human hepatocellular carcinoma cell lines (HepG2 cells) and biodistribution studies in albino rats of Sprague-Dawley strain. Lipoprotein anchored dendrimeric nanoconstructs showed significant uptake by cancer cells as well as higher biodistribution of docetaxel to liver and spleen. It is concluded that these precisely synthesized engineered dendrimeric nanoconstructs could serve as promising drug carrier for fighting with the fatal disease, i.e., cancer, attributed to their defined targeting and therapeutic potential.

Lipoproteins tethered dendrimeric nanoconstructs for effective targeting to cancer cells

Energy Technology Data Exchange (ETDEWEB)

Jain, Anupriya; Jain, Keerti, E-mail: keertijain02@gmail.com; Mehra, Neelesh Kumar, E-mail: neelesh81mph@gmail.com; Jain, N. K., E-mail: dr.jnarendr@gmail.com [Dr. H. S. Gour University, Pharmaceutics Research Laboratory, Department of Pharmaceutical Sciences (India)

2013-10-15

In the present investigation, poly (propylene imine) dendrimers up to fifth generation (PPI G5.0) were synthesized using ethylene diamine and acrylonitrile. Lipoproteins (high-density lipoprotein; HDL and low-density lipoprotein; LDL) were isolated from human plasma by discontinuous density gradient ultracentrifugation, characterized and tethered to G5.0 PPI dendrimers to construct LDL- and HDL-conjugated dendrimeric nanoconstructs for tumor-specific delivery of docetaxel. Developed formulations showed sustained release characteristics in in vitro drug release and in vivo pharmacokinetic studies. The cancer targeting potential of lipoprotein coupled dendrimers was investigated by ex vivo cytotoxicity and cell uptake studies using human hepatocellular carcinoma cell lines (HepG2 cells) and biodistribution studies in albino rats of Sprague-Dawley strain. Lipoprotein anchored dendrimeric nanoconstructs showed significant uptake by cancer cells as well as higher biodistribution of docetaxel to liver and spleen. It is concluded that these precisely synthesized engineered dendrimeric nanoconstructs could serve as promising drug carrier for fighting with the fatal disease, i.e., cancer, attributed to their defined targeting and therapeutic potential.

Lipoprotein Transport: Greasing the Machines of Outer Membrane Biogenesis: Re-Examining Lipoprotein Transport Mechanisms Among Diverse Gram-Negative Bacteria While Exploring New Discoveries and Questions.

Science.gov (United States)

Grabowicz, Marcin

2018-04-01

The Gram-negative outer membrane (OM) is a potent permeability barrier against antibiotics, limiting clinical options amid mounting rates of resistance. The Lol transport pathway delivers lipoproteins to the OM. All the OM assembly machines require one or more OM lipoprotein to function, making the Lol pathway central for all aspects of OM biogenesis. The Lol pathways of many medically important species clearly deviate from the Escherichia coli paradigm, perhaps with implications for efforts to develop novel antibiotics. Moreover, recent work reveals the existence of an undiscovered alternate route for bringing lipoproteins to the OM. Here, lipoprotein transport mechanisms, and the quality control systems that underpin them, is re-examined in context of their diversity. © 2018 WILEY Periodicals, Inc.

Triglyceride-Rich Lipoproteins and Atherosclerotic Cardiovascular Disease

DEFF Research Database (Denmark)

Nordestgaard, Børge G

2016-01-01

Scientific interest in triglyceride-rich lipoproteins has fluctuated over the past many years, ranging from beliefs that these lipoproteins cause atherosclerotic cardiovascular disease (ASCVD) to being innocent bystanders. Correspondingly, clinical recommendations have fluctuated from a need.......1-fold for myocardial infarction, 3.2-fold for ischemic heart disease, 3.2-fold for ischemic stroke, and 2.2-fold for all-cause mortality. Also, genetic studies using the Mendelian randomization design, an approach that minimizes problems with confounding and reverse causation, now demonstrate...

Lipoprotein (a) and biochemical parameters in elderly

OpenAIRE

Yuttana Sudjaroen

2016-01-01

Background: Lipoprotein (a) [Lp(a)] is an low-density lipoprotein like particle and is an important independent risk factor for coronary artery diseases (CAD). Few studies on Lp(a) level in Thai elderly to screening risk of CAD may concerned. Aims: To study the relation of Lp(a) level and routine biochemical parameters including lipid profiles and fasting blood glucose in elderly and to determine risk of subclinical symptoms by using Lp(a) levels as early risk predictor. Settings and Design: ...

Environment-Mediated Accumulation of Diacyl Lipoproteins over Their Triacyl Counterparts in Staphylococcus aureus

Science.gov (United States)

Kurokawa, Kenji; Kim, Min-Su; Ichikawa, Rie; Ryu, Kyoung-Hwa; Dohmae, Naoshi

2012-01-01

Bacterial lipoproteins are believed to exist in only one specific lipid-modified structure, such as the diacyl form or the triacyl form, in each bacterium. In the case of Staphylococcus aureus, recent extensive matrix-assisted laser desorption ionization–time of flight (MALDI-TOF) mass spectrometry analysis revealed that S. aureus lipoproteins exist in the α-aminoacylated triacyl form. Here, we discovered conditions that induce the accumulation of diacyl lipoproteins that lack α-aminoacylation in S. aureus. The accumulation of diacyl lipoproteins required a combination of conditions, including acidic pH and a post-logarithmic-growth phase. High temperatures and high salt concentrations additively accelerated the accumulation of the diacyl lipoprotein form. Following a post-logarithmic-growth phase where S. aureus MW2 cells were grown at pH 6, SitC lipoprotein was found almost exclusively in its diacyl structure rather than in its triacyl structure. This is the first report showing that the environment mediates lipid-modified structural alterations of bacterial lipoproteins. PMID:22467779

The lipid- and lipoprotein- [LDL-Lp(a)] apheresis techniques. Updating.

Science.gov (United States)

Stefanutti, C; Morozzi, C; Perrone, G; Di Giacomo, S; Vivenzio, A; D'Alessandri, G

2012-01-01

Therapeutic plasmapheresis allows the extracorporeal removal of plasmatic lipoproteins (Lipid-apheresis) (LA). It can be non selective (non specific), semi - selective or selective low density lipoprotein-lipoprotein(a) (specific [LDL- Lp(a)] apheresis) (Lipoprotein apheresis, LDLa). The LDL removal rate is a perfect parameter to assess the system efficiency. Plasma-Exchange (PEX) cannot be considered either specific nor, selective. In PEX the whole blood is separated into plasma and its corpuscular components usually through centrifugation or rather filtration. The corpuscular components mixed with albumin solution plus saline (NaCl 0.9%) solution at 20%-25%, are then reinfused to the patient, to substitute the plasma formerly removed. PEX eliminates atherogenic lipoproteins, but also other essential plasma proteins, such as albumin, immunoglobulins, and hemocoagulatory mediators. Cascade filtration (CF) is a method based on plasma separation and removal of plasma proteins through double filtration. During the CF two hollow-fiber filters with pores of different diameter are used to eliminate the plasma components of different weight and molecular diameter. A CF system uses a first polypropylene filter with 0.55 µm diameter pores and a second one of diacetate of cellulose with 0.02 µm pores. The first filter separates the whole blood, and the plasma is then perfused through a second filter which allows the recovery of molecules with a diameter lower than 0.02 µm, and the removal of molecules larger in diameter as apoB100-containing lipoproteins. Since both albumin and immunoglobulins are not removed, or to a negligible extent, plasma-expanders, substitution fluids, and in particular albumin, as occurs in PEX are not needed. CF however, is characterized by lower selectivity since removes also high density lipoprotein (HDL) particles which have an antiatherogenic activity. In the 80's, a variation of Lipid-apheresis has been developed which allows the LDL

The Influence of Decreased Levels of High Density Lipoprotein ...

African Journals Online (AJOL)

Background: Changes in lipoproteins levels in sickle cell disease (SCD) patients are well.known, but the physiological ramifications of the low levels observed have not been entirely resolved. Aim: The aim of this study is to evaluate the impact of decreased levels of high density lipoprotein cholesterol (HDL.c) on ...

Thyroid hormone reduces PCSK9 and stimulates bile acid synthesis in humans[S

Science.gov (United States)

Bonde, Ylva; Breuer, Olof; Lütjohann, Dieter; Sjöberg, Stefan; Angelin, Bo; Rudling, Mats

2014-01-01

Reduced plasma LDL-cholesterol is a hallmark of hyperthyroidism and is caused by transcriptional stimulation of LDL receptors in the liver. Here, we investigated whether thyroid hormone (TH) actions involve other mechanisms that may also account for the reduction in LDL-cholesterol, including effects on proprotein convertase subtilisin/kexin type 9 (PCSK9) and bile acid synthesis. Twenty hyperthyroid patients were studied before and after clinical normalization, and the responses to hyperthyroidism were compared with those in 14 healthy individuals after 14 days of treatment with the liver-selective TH analog eprotirome. Both hyperthyroidism and eprotirome treatment reduced circulating PCSK9, lipoprotein cholesterol, apoB and AI, and lipoprotein(a), while cholesterol synthesis was stable. Hyperthyroidism, but not eprotirome treatment, markedly increased bile acid synthesis and reduced fibroblast growth factor (FGF) 19 and dietary cholesterol absorption. Eprotirome treatment, but not hyperthyroidism, reduced plasma triglycerides. Neither hyperthyroidism nor eprotirome treatment altered insulin, glucose, or FGF21 levels. TH reduces circulating PSCK9, thereby likely contributing to lower plasma LDL-cholesterol in hyperthyroidism. TH also stimulates bile acid synthesis, although this response is not critical for its LDL-lowering effect. PMID:25172631

Characterization of lipoproteins in human and canine cerebrospinal fluid (CSF)

International Nuclear Information System (INIS)

Pitas, R.E.; Weisgraber, K.H.; Boyles, J.K.; Lee, S.; Mahley, R.W.

1986-01-01

Previously the authors demonstrated that rat brain astrocytes in vitro synthesize and secrete apo-E and possess apo-B,E(LDL) receptors. The apo-E secreted by astrocytes and apo-E in rat brain extracts differed from serum apo-E in two respects. Brain apo-E had a higher apparent molecular weight and a higher percentage of more acidic isoforms. To characterize further the apo-E within the central nervous system, apo-E in human and canine CSF was investigated. Compared to plasma apo-E, CSF apo-E had a higher apparent M/sub r/ and a higher percentage of acidic isoforms which were sialylated, as shown by neuraminidase digestion. The apo-E in human CSF was approx.5-10% of the plasma level. In CSF 60-80% of the apo-E was in lipoproteins with d = 1.09-1.15. The remainder of the apo-E was in the d > 1.21 fraction. Human CSF lipoproteins were primarily spherical (110-190 A) while canine CSF lipoproteins were a mixture of discs (205 x 65 A) while canine CSF lipoproteins were a mixture of discs (205 x 65 A) and spheres (100-150 A). The CSF also contained apo-AI in the d = 1.09-1.15 g/ml fraction. Human CSF lipoproteins containing both apo-E and apo-AI were isolated on an anti-apo-E affinity column, suggesting that apo-E and AI occurred in the same particles. The CSF apo-E-containing lipoproteins competed for binding of 125 I-LDL to the apo-B,E(LDL) receptor. There was no detectable apo-B in CSF. These data suggest that CSF lipoproteins might transport lipid and regulate lipid homeostasis within the brain

High-density lipoproteins and adrenal steroidogenesis : A population-based study

NARCIS (Netherlands)

Buitenwerf, Edward; Kerstens, Michiel N.; Links, Thera P.; Kema, Ido P.; Dullaart, Robin P. F.

BACKGROUND: Cholesterol trafficked within plasma lipoproteins, in particular high-density lipoproteins (HDL), may represent an important source of cholesterol that is required for adrenal steroidogenesis. Based on a urinary gas chromatography method, compromised adrenal function has been suggested

Mechanism of action of gemfibrozil on lipoprotein metabolism.

OpenAIRE

Saku, K; Gartside, P S; Hynd, B A; Kashyap, M L

1985-01-01

Gemfibrozil is a potent lipid regulating drug whose major effects are to increase plasma high density lipoproteins (HDL) and to decrease plasma triglycerides (TG) in a wide variety of primary and secondary dyslipoproteinemias. Its mechanism of action is not clear. Six patients with primary familial endogenous hypertriglyceridemia with fasting chylomicronemia (type V lipoprotein phenotype) with concurrent subnormal HDL cholesterol levels (HDL deficiency) were treated initially by diet and once...

Binding of digitoxin and digoxin to normal human β-lipoproteins

International Nuclear Information System (INIS)

Brock, A.

1976-01-01

The binding of digitoxin and digoxin to purified β-lipoprotein, obtained from pooled normal human serum, was studied under equilibrium conditions. Even with as high concentrations of unbound digitoxin or digoxin as 4 μmol/l, the preparations of β-lipoproteins, containing cholesterol 1.98-3.95 mmol/l, showed no signs of saturation. The binding affinity of digitoxin was about ten times as high as that of digoxin. Gel filtration chromatography, performed on native serum after addition of 3 H-digitoxin or 3 H-digoxin, showed a minor fraction of the cardiac glycosides to be associated with te protein fraction of highest molecular weight. This phenomenon disappeared after precipitation of the β-lipoproteins. In clinical relations the contribution of protein-bound digitoxin caused by the lipoprotein interaction is immaterial compared to that caused by the albumin interaction. (author)

Influence of impaired lipoprotein biogenesis on surface and exoproteome of Streptococcus pneumoniae.

Science.gov (United States)

Pribyl, Thomas; Moche, Martin; Dreisbach, Annette; Bijlsma, Jetta J E; Saleh, Malek; Abdullah, Mohammed R; Hecker, Michael; van Dijl, Jan Maarten; Becher, Dörte; Hammerschmidt, Sven

2014-02-07

Surface proteins are important for the fitness and virulence of the Gram-positive pathogen Streptococcus pneumoniae. They are crucial for interaction of the pathogen with its human host during infection. Therefore, the analysis of the pneumococcal surface proteome is an important task that requires powerful tools. In this study, two different methods, an optimized biotinylation approach and shaving with trypsin beads, were applied to study the pneumococcal surface proteome and to identify surface-exposed protein domains, respectively. The identification of nearly 95% of the predicted lipoproteins and 75% of the predicted sortase substrates reflects the high coverage of the two classical surface protein classes accomplished in this study. Furthermore, the biotinylation approach was applied to study the impact of an impaired lipoprotein maturation pathway on the cell envelope proteome and exoproteome. Loss of the lipoprotein diacylglyceryl transferase Lgt leads to striking changes in the lipoprotein distribution. Many lipoproteins disappear from the surface proteome and accumulate in the exoproteome. Further insights into lipoprotein processing in pneumococci are provided by immunoblot analyses of bacterial lysates and corresponding supernatant fractions. Taken together, the first comprehensive overview of the pneumococcal surface and exoproteome is presented, and a model for lipoprotein processing in S. pneumoniae is proposed.

Effect of high density lipoproteins on permeability of rabbit aorta to low density lipoproteins

International Nuclear Information System (INIS)

Klimov, A.N.; Popov, V.A.; Nagornev, V.A.; Pleskov, V.M.

1985-01-01

A study was made on the effect of high density lipoproteins (HDL) on the permeability of rabbit aorta to low density lipoproteins (LDL) after intravenous administration of human HDL and human ( 125 I)LDL to normal and hypercholesterolemic rabbits. Evaluation of radioactivity in plasma and aorta has shown that the administration of a large dose of HDL decreased the aorta permeability rate for ( 125 I)LDL on an average by 19% in normal rabbits, and by 45% in rabbits with moderate hypercholesterolemia. A historadiographic study showed that HDL also decreased the vessel wall permeability to ( 125 I)LDL in normal and particularly in hypercholesterolemic animals. The suggestion was made that HDL at very high molar concentration can hamper LDL transportation through the intact endothelial layer into the intima due to the ability of HDL to compete with LDL in sites of low affinity on the surface of endothelial cells. (author)

Acetaldehyde binding increases the catabolism of rat serum low-density lipoproteins

International Nuclear Information System (INIS)

Savolainen, M.J.; Baraona, E.; Lieber, C.S.

1987-01-01

Acetaldehyde was found to form adducts with rat serum lipoproteins. The binding of [ 14 C]acetaldehyde to lipoproteins was studied at low concentrations which are known to exist during ethanol oxidation. The amount of lipoprotein adducts was a linear function of acetaldehyde concentration up to 250 μM. Incubation of rat plasma low-density lipoproteins (LDL) with 200 μM acetaldehyde increased the disappearance rate of the 3 H-label from the cholesterol ester moiety of LDL injected into normal rats. The data show that even low concentrations of acetaldehyde are capable of affecting LDL metabolism. These findings may provide an explanation for the low concentrations of serum LDL in alcoholics. The alcohol-induced hyperlipidemia includes either a lack of increase or a decrease in the low-density lipoprotein (LDL) concentration, but the underlying mechanism is not known. It has been shown previously, that the acetylation of lysine residues of LDL apoprotein (apoB) by acetanhydride leads to rapid uptake of LDL particles by macrophages through a non-LDL receptor pathway. Since acetaldehyde, the first toxic metabolite of ethanol, is a chemically reactive compound capable of binding to proteins, they tested whether acetaldehyde forms adducts with serum lipoproteins and subsequently alters the catabolism of LDL. 19 references, 2 figures, 1 table

Plasma Lipoprotein(a Levels and Atherosclerotic Renal Artery Stenosis in Hypertensive Patients

Directory of Open Access Journals (Sweden)

Cristiana Catena

2015-03-01

Full Text Available Background/Aims: The contribution of emergent cardiovascular risk factors to atherosclerotic renal artery stenosis (ARAS is debated. We investigated the relationship of lipoprotein(a and prothrombotic factors with ARAS in hypertension. Methods: In 50 hypertensive patients with angiographic evidence of ARAS and 58 hypertensive patients who had comparable cardiovascular risk factor burden but no evidence of renovascular disease, we measured renal function, lipoprotein(a, homocysteine, and hemostatic-fibrinolytic markers. Results: Patients with ARAS were more frequently smokers and had longer duration of hypertension, heavier antihypertensive treatment, and worse renal function than controls. Lipoprotein(a was higher in patients with ARAS than controls, whereas no differences were found in homocysteine and all hemostatic variables. Multivariate analysis showed that lipoprotein(a was associated with ARAS independent of other confounders including renal function and history of coronary heart, cerebrovascular, and peripheral artery disease. Conclusion: Lipoprotein(a might contribute to the development of ARAS and detection of elevated levels of this lipoprotein could raise the suspicion of renovascular disease in patients with high blood pressure.

Structural and metabolic heterogeneity of plasma low density lipoproteins in nonhuman primates

International Nuclear Information System (INIS)

Marzetta, C.A.

1986-01-01

To test the hypothesis that a variety of precursor particles secreted by the liver could result in heterogeneity of LDL products in plasma, the metabolic fate of selected radiolabeled hepatic lipoproteins evaluated was determined in vivo. The hepatic lipoproteins evaluated were isolated from liver perfusate and were triglyceride-rich VLDL (d < 1.006 or d < 1.017) and phospholipid-rich LDL (1.017 < d < 1.049 or 1.030 < d < 1.063). Radiolabeled autologous plasma LDL were injected into recipient animals together with the radiolabeled hepatic lipoproteins. Density gradient ultracentrifugation and gel filtration were used to characterize the distribution of radiolabeled lipoproteins in the plasma at selected times after injection. A variety of hepatic lipoproteins were precursors to lipoproteins that resembled plasma LDL. Between 22 to 80% of the injected dose of radiolabeled hepatic lipoprotein apo B-100 was converted to plasma LDL-like particles, regardless of the type of hepatic lipoprotein injected. A kinetic model was generated to describe the metabolic behavior of hepatic VLDL-derived and plasma LDL-derived apo B-100 radioactivity. Both models required multiple metabolic pools to fit the data. Hepatic VLDL-derived apo B-100 radioactivity was metabolized rapidly into various kinds of LDL subfractions. This rapid conversion of hepatic VLDL apo B-100 to LDL apo B-100 may be analogous to the portion of plasma VLDL that gets converted to LDL without passing through the delipidation cascade that has been described in humans and has been termed direct LDL production

Triglyceride-rich lipoproteins as a causal factor for cardiovascular disease

Directory of Open Access Journals (Sweden)

Toth PP

2016-05-01

Full Text Available Peter P Toth1,2 1Ciccarone Center for the Prevention of Cardiovascular Disease, Johns Hopkins University School of Medicine, Baltimore, MD, 2Preventive Cardiology, CGH Medical Center, Sterling, IL, USA Abstract: Approximately 25% of US adults are estimated to have hypertriglyceridemia (triglyceride [TG] level ≥150 mg/dL [≥1.7 mmol/L]. Elevated TG levels are associated with increased cardiovascular disease (CVD risk, and severe hypertriglyceridemia (TG levels ≥500 mg/dL [≥5.6 mmol/L] is a well-established risk factor for acute pancreatitis. Plasma TG levels correspond to the sum of the TG content in TG-rich lipoproteins (TRLs; ie, very low-density lipoproteins plus chylomicrons and their remnants. There remains some uncertainty regarding the direct causal role of TRLs in the progression of atherosclerosis and CVD, with cardiovascular outcome studies of TG-lowering agents, to date, having produced inconsistent results. Although low-density lipoprotein cholesterol (LDL-C remains the primary treatment target to reduce CVD risk, a number of large-scale epidemiological studies have shown that elevated TG levels are independently associated with increased incidence of cardiovascular events, even in patients treated effectively with statins. Genetic studies have further clarified the causal association between TRLs and CVD. Variants in several key genes involved in TRL metabolism are strongly associated with CVD risk, with the strength of a variant's effect on TG levels correlating with the magnitude of the variant's effect on CVD. TRLs are thought to contribute to the progression of atherosclerosis and CVD via a number of direct and indirect mechanisms. They directly contribute to intimal cholesterol deposition and are also involved in the activation and enhancement of several proinflammatory, proapoptotic, and procoagulant pathways. Evidence suggests that non-high-density lipoprotein cholesterol, the sum of the total cholesterol carried by

Overexpression of porcine lipoprotein-associated phospholipase A2 in swine

NARCIS (Netherlands)

Tang, Xiaochun; Wang, Gangqi; Liu, Xingxing; Han, Xiaolei; Li, Zhuang; Ran, Guangyao; Li, Zhanjun; Song, Qi; Ji, Y; Wang, Haijun; Wang, Yuhui; Ouyang, Hongsheng; Pang, Daxin

2015-01-01

Lipoprotein-associated phospholipase A 2 (Lp-PLA2) is associated with the risk of vascular disease. It circulates in human blood predominantly in association with low-density lipoprotein cholesterol (LDL-C) and hydrolyses oxidized phospholipids into pro-inflammatory products. However, in the mouse

Human luteinized granulosa cells secrete apoB100-containing lipoproteins

NARCIS (Netherlands)

Gautier, Thomas; Becker, Steffi; Drouineaud, Veronique; Menetrier, Franck; Sagot, Paul; Nofer, Jerzy-Roch; von Otte, Soeren; Lagrost, Laurent; Masson, David; Tietge, Uwe J. F.

Thus far, liver, intestine, heart, and placenta have been shown to secrete apolipoprotein (apo) B-containing lipoproteins. In the present study, we first investigated lipoproteins in human follicular fluid (FF), surrounding developing oocytes within the ovary, as well as in corresponding plasma

Ultracentrifugal and electrophoretic characteristics of the plasma lipoproteins of miniature schnauzer dogs with idiopathic hyperlipoproteinemia.

Science.gov (United States)

Whitney, M S; Boon, G D; Rebar, A H; Story, J A; Bottoms, G D

1993-01-01

To better characterize the idiopathic hyperlipoproteinemia of Miniature Schnauzer dogs, the plasma lipoproteins of 20 Miniature Schnauzers (MS) and 11 dogs of other breeds (DOB) were evaluated by ultracentrifugation, electrophoresis, and biochemical tests. Seventeen MS were healthy; 3 had diabetes mellitus. Plasma from 6 of 17 healthy and all 3 diabetic MS was visibly lipemic. Lipemia was slight to marked in healthy lipemic MS, and marked in diabetic ones. All DOB had clear plasma; 8 were healthy and 3 had diabetes. All healthy lipemic MS and diabetic lipemic MS had hypertriglyceridemia associated with excess very low density lipoproteins. Chylomicronemia was present in 4 of 6 healthy lipemic MS and all 3 diabetic lipemic MS. Lipoproteins with ultracentrifugal and electrophoretic characteristics of normal low density lipoprotein were lacking in 4 of 6 healthy lipemic MS. The lipoprotein patterns of 4 of 11 healthy nonlipemic MS were characterized by mild hypertriglyceridemia associated with increased very low density lipoproteins and a lack of lipoproteins with characteristics of normal low density lipoproteins. Lipoprotein patterns of diabetic DOB closely resembled those of healthy DOB; those of diabetic lipemic MS resembled those of markedly lipemic healthy lipemic MS. In conclusion, the hyperlipoproteinemia of Miniature Schnauzers is characterized by increased very low density lipoproteins with or without accompanying chylomicronemia; some affected dogs may have decreased low density lipoproteins.

Cellular uptake of lipoproteins and persistent organic compounds-An update and new data

International Nuclear Information System (INIS)

Hjelmborg, Philip Sebastian; Andreassen, Thomas Kjaergaard; Bonefeld-Jorgensen, Eva Cecilie

2008-01-01

There are a number of interactions related to the transport of lipophilic xenobiotic compounds in the blood stream of mammals. This paper will focus on the interactions between lipoproteins and persistent organic pollutants (POPs) and how these particles are taken up by cells. A number of POPs including the pesticide p,p'-dichlorodiphenyltrichloroethane (DDT), and especially its metabolite p,p'-dichlorodiphenyldichloroethene (DDE), interacts with nuclear hormone receptors causing these to malfunction, which in turn results in a range of deleterious health effects in humans. The aim of the present study was to determine the role of lipoprotein receptors in mouse embryonic fibroblast (MEF) cells in conjunction with uptake of DDT-lipoprotein complexes from supplemented media in vitro. Uptake of DDT by MEF cells was investigated using MEF1 cells carrying the receptors low-density lipoprotein receptor-related protein (LRP) and low-density lipoprotein receptor (LDLR) present and MEF4 cells with no LRP and LDLR expression. Cells were incubated together with the complex of low-density lipoproteins (LDL) and [ 14 C]DDT. The receptor function was further evaluated by adding the 40 kDa receptor-associated protein (RAP) which blocks receptor activity. The results showed that [ 14 C]DDT uptake was decreasing when the LDL concentration was increasing. There was no strong evidence for a receptor-mediated uptake of the [ 14 C]DDT-lipoprotein complex. To conclude, DDT travels in the blood stream and can cross cell membranes while being transported as a DDT-lipoprotein complex. The lipoproteins do not need receptors to cross cell membranes since passive diffusion constitutes a major passageway

A clustering analysis of lipoprotein diameters in the metabolic syndrome

Science.gov (United States)

The presence of smaller low-density lipoproteins (LDL) has been associated with atherosclerosis risk, and the insulin resistance (IR) underlying the metabolic syndrome (MetS). In addition, some research has supported the association of very low-, low- and high-density lipoprotein (VLDL HDL) particle...

Hepatitis C virus relies on lipoproteins for its life cycle.

Science.gov (United States)

Grassi, Germana; Di Caprio, Giorgia; Fimia, Gian Maria; Ippolito, Giuseppe; Tripodi, Marco; Alonzi, Tonino

2016-02-14

Hepatitis C virus (HCV) infects over 150 million people worldwide. In most cases, HCV infection becomes chronic causing liver disease ranging from fibrosis to cirrhosis and hepatocellular carcinoma. Viral persistence and pathogenesis are due to the ability of HCV to deregulate specific host processes, mainly lipid metabolism and innate immunity. In particular, HCV exploits the lipoprotein machineries for almost all steps of its life cycle. The aim of this review is to summarize current knowledge concerning the interplay between HCV and lipoprotein metabolism. We discuss the role played by members of lipoproteins in HCV entry, replication and virion production.

Impact of hormonal contraception and weight loss on high-density lipoprotein cholesterol efflux and lipoprotein particles in women with polycystic ovary syndrome.

Science.gov (United States)

Dokras, Anuja; Playford, Martin; Kris-Etherton, Penny M; Kunselman, Allen R; Stetter, Christy M; Williams, Nancy I; Gnatuk, Carol L; Estes, Stephanie J; Sarwer, David B; Allison, Kelly C; Coutifaris, Christos; Mehta, Nehal; Legro, Richard S

2017-05-01

To study the effects of oral contraceptive pills (OCP), the first-line treatment for PCOS, on high-density lipoprotein cholesterol (HDL-C) function (reverse cholesterol efflux capacity) and lipoprotein particles measured using nuclear magnetic resonance spectroscopy in obese women. Secondary analysis of a randomized controlled trial (OWL-PCOS) of OCP or Lifestyle (intensive Lifestyle modification) or Combined (OCP + Lifestyle) treatment groups for 16 weeks. Eighty-seven overweight/obese women with PCOS at two academic centres. Change in HDL-C efflux capacity and lipoprotein particles. High-density lipoprotein cholesterol efflux capacity increased significantly at 16 weeks in the OCP group [0·11; 95% confidence interval (CI) 0·03, 0·18, P = 0·008] but not in the Lifestyle (P = 0·39) or Combined group (P = 0·18). After adjusting for HDL-C and TG levels, there was significant mean change in efflux in the Combined group (0·09; 95% CI 0·01, 0·15; P = 0·01). Change in HDL-C efflux correlated inversely with change in serum testosterone (r s = -0·21; P = 0·05). In contrast, OCP use induced an atherogenic low-density lipoprotein cholesterol (LDL-C) profile with increase in small (P = 0·006) and large LDL-particles (P = 0·002). Change in small LDL-particles correlated with change in serum testosterone (r s = -0·31, P = 0·009) and insulin sensitivity index (ISI; r s = -0·31, P = 0·02). Both Lifestyle and Combined groups did not show significant changes in the atherogenic LDL particles. Oral contraceptive pills use is associated with improved HDL-C function and a concomitant atherogenic LDL-C profile. Combination of a Lifestyle program with OCP use improved HDL-C function and mitigated adverse effects of OCP on lipoproteins. Our study provides evidence for use of OCP in overweight/obese women with PCOS when combined with Lifestyle changes. © 2017 John Wiley & Sons Ltd.

Comparison of 2 electrophoretic methods and a wet-chemistry method in the analysis of canine lipoproteins.

Science.gov (United States)

Behling-Kelly, Erica

2016-03-01

The evaluation of lipoprotein metabolism in small animal medicine is hindered by the lack of a gold standard method and paucity of validation data to support the use of automated chemistry methods available in the typical veterinary clinical pathology laboratory. The physical and chemical differences between canine and human lipoproteins draw into question whether the transference of some of these human methodologies for the study of canine lipoproteins is valid. Validation of methodology must go hand in hand with exploratory studies into the diagnostic or prognostic utility of measuring specific lipoproteins in veterinary medicine. The goal of this study was to compare one commercially available wet-chemistry method to manual and automated lipoprotein electrophoresis in the analysis of canine lipoproteins. Canine lipoproteins from 50 dogs were prospectively analyzed by 2 electrophoretic methods, one automated and one manual method, and one wet-chemistry method. Electrophoretic methods identified a higher proportion of low-density lipoproteins than the wet-chemistry method. Automated electrophoresis occasionally failed to identify very low-density lipoproteins. Wet-chemistry methods designed for evaluation of human lipoproteins are insensitive to canine low-density lipoproteins and may not be applicable to the study of canine lipoproteins. Automated electrophoretic methods will likely require significant modifications if they are to be used in the analysis of canine lipoproteins. Studies aimed at determining the impact of a disease state on lipoproteins should thoroughly investigate the selected methodology prior to the onset of the study. © 2016 American Society for Veterinary Clinical Pathology.

Application of directly coupled HPLC MMR to separation and characterization of lipoproteins from human serum

DEFF Research Database (Denmark)

Daykin, C. A.; Corcoran, O.; Hansen, S. H.

2001-01-01

method for the separation of highdensity lipoprotein, low-density lipoprotein, and very low-density lipoprotein from intact serum or plasma. The separation was achieved using a hydroxyapatite column and elution with pH 7.4 phosphate buffer with 100-muL injections of whole plasma. Coelution of HDL...... run time was 90 min with stopped-now 600-MHz NMR spectra of each lipoprotein being collected using 128 scans, in 7 min. The H-1 NMR chemical shifts of lipid signals were identical to conventional NMR spectra of freshly prepared lipoprotein standards, confirming that the lipoproteins were not degraded...

The effect of interaction between Lipoprotein Lipase and ApoVLDL-II ...

African Journals Online (AJOL)

GREGO

2007-04-02

Apr 2, 2007 ... correlation between growth and fitness is not absolute, it ... significant differences are found in the plasma triglyceride ... (VLDL) and high density lipoprotein (HDL) concentration ... High-density lipoprotein cholesterol was.

The biological properties of iron oxide core high-density lipoprotein in experimental atherosclerosis

NARCIS (Netherlands)

Skajaa, Torjus; Cormode, David P.; Jarzyna, Peter A.; Delshad, Amanda; Blachford, Courtney; Barazza, Alessandra; Fisher, Edward A.; Gordon, Ronald E.; Fayad, Zahi A.; Mulder, Willem J. M.

2011-01-01

Lipoproteins are a family of plasma nanoparticles responsible for the transportation of lipids throughout the body. High-density lipoprotein (HDL), the smallest of the lipoprotein family, measures 7-13 nm in diameter and consists of a cholesteryl ester and triglyceride core that is covered with a

Serum lipids and lipoproteins in patients with psoriasis.

Science.gov (United States)

Taheri Sarvtin, Mehdi; Hedayati, Mohammad Taghi; Shokohi, Tahereh; HajHeydari, Zohreh

2014-05-01

Psoriasis is a common chronic and recurrent inflammatory skin disorder characterized by hyperproliferation of keratinocytes and infiltration of T cells, monocytes/macrophages and neutrophils into dermal and epidermal layers of the skin. The prevalence of cardiovascular disorders in these patients is remarkably higher compared to normal individuals, which seems to be associated with the hyperlipidemia. This study was designed and conducted to investigate the serum lipid profile in psoriatic patients and its association with the severity of disease. This case-control study was performed on 50 plaque-type psoriasis patients and 50 healthy individuals as control, matched for age and sex. Blood samples were collected after 14 h fasting. Serum triglyceride, cholesterol and lipoproteins were assayed using the standard kit (made by Pars Azmon Co. Iran). Certain parameters, including serum triglyceride, cholesterol, low density lipoprotein (LDL), and very low density lipoprotein (VLDL), were significantly higher in the case group compared to the controls (P lipoprotein (HDL) was significantly lower in the former (P < 0.001). In addition, there was a significant relationship between severity of psoriasis and serum lipid profile. The results have revealed the higher plasma level of lipids in psoriatic patients. This may elevate the risk of atherosclerosis, particularly cardiovascular disorders. Therefore, from the epidemiological point of view, screening psoriatic patients, particularly those with severe psoriasis, is recommended.

High lipoprotein(a) as a possible cause of clinical familial hypercholesterolaemia

DEFF Research Database (Denmark)

Langsted, Anne; Kamstrup, Pia Rørbœk; Benn, Marianne

2016-01-01

, and that individuals with both high lipoprotein(a) concentrations and clinical familial hypercholesterolaemia have the highest risk of myocardial infarction. METHODS: We did a prospective cohort study that included data from 46 200 individuals from the Copenhagen General Population Study who had lipoprotein...... cholesterol, mean lipoprotein(a) concentrations were 23 mg/dL in individuals unlikely to have familial hypercholesterolaemia, 32 mg/dL in those with possible familial hypercholesterolaemia, and 35 mg/dL in those with probable or definite familial hypercholesterolaemia (ptrend... LDL cholesterol for lipoprotein(a) cholesterol content the corresponding values were 24 mg/dL for individuals unlikely to have familial hypercholesterolaemia, 22 mg/dL for those with possible familial hypercholesterolaemia, and 21 mg/dL for those with probable or definite familial...

Dietary fatty acids were not independently associated with lipoprotein subclasses in elderly women.

Science.gov (United States)

Alaghehband, Fatemeh Ramezan; Lankinen, Maria; Värri, Miika; Sirola, Joonas; Kröger, Heikki; Erkkilä, Arja T

2017-07-01

Dietary fatty acids are known to affect serum lipoproteins; however, little is known about the associations between consumption of dietary fatty acids and lipoprotein subclasses. In this study, we hypothesized that there is an association between dietary fatty acids and lipoprotein subclasses and investigated the cross-sectional association of dietary fat intake with subclasses of lipoproteins in elderly women. Altogether, 547 women (aged ≥65 years) who were part of OSTPRE cohort participated. Dietary intake was assessed by 3-day food records, lifestyle, and health information obtained through self-administrated questionnaires, and lipoprotein subclasses were determined by nuclear magnetic resonance spectroscopy. To analyze the associations between fatty acids and lipoprotein subclasses, we used Pearson and Spearman correlation coefficients and the analysis of covariance (ANCOVA) test with, adjustment for physical activity, body mass index, age, smoking status, and intake of lipid-lowering drugs. There were significant correlations between saturated fatty acids (SFA; % of energy) and concentrations of large, medium, and small low-density lipoproteins (LDL); total cholesterol in large, medium, and small LDL; and phospholipids in large, medium, and small LDL, after correction for multiple testing. After adjustment for covariates, the higher intake of SFA was associated with smaller size of LDL particles (P = .04, ANCOVA) and lower amount of triglycerides in small very low-density lipoproteins (P = .046, ANCOVA). However, these associations did not remain significant after correction for multiple testing. In conclusion, high intake of SFA may be associated with the size of LDL particles, but the results do not support significant, independent associations between dietary fatty acids and lipoprotein subclasses. Copyright © 2017 Elsevier Inc. All rights reserved.

Elevated plasma low-density lipoprotein and high-density lipoprotein cholesterol levels in amenorrheic athletes: effects of endogenous hormone status and nutrient intake.

Science.gov (United States)

Friday, K E; Drinkwater, B L; Bruemmer, B; Chesnut, C; Chait, A

1993-12-01

To determine the interactive effects of hormones, exercise, and diet on plasma lipids and lipoproteins, serum estrogen and progesterone levels, nutrient intake, and plasma lipid, lipoprotein, and apolipoprotein concentrations were measured in 24 hypoestrogenic amenorrheic and 44 eumenorrheic female athletes. When compared to eumenorrheic athletes, amenorrheic athletes had higher levels of plasma cholesterol (5.47 +/- 0.17 vs. 4.84 +/- 0.12 mmol/L, P = 0.003), triglyceride (0.75 +/- 0.06 vs. 0.61 +/- 0.03 mmol/L, P = 0.046), low-density lipoprotein (LDL; 3.16 +/- 0.15 vs. 2.81 +/- 0.09 mmol/L, P = 0.037), high-density lipoprotein (HDL; 1.95 +/- 0.07 vs. 1.73 +/- 0.05 mmol/L, P = 0.007), and HDL2 (0.84 +/- 0.06 vs. 0.68 +/- 0.04 mmol/L, P = 0.02) cholesterol. Plasma LDL/HDL cholesterol ratios, very low-density lipoprotein and HDL3 cholesterol, and apolipoprotein A-I and A-II levels were similar in the two groups. Amenorrheic athletes consumed less fat than eumenorrheic subjects (52 +/- 5 vs. 75 +/- 3 g/day, P = 0.02), but similar amounts of calories, cholesterol, protein, carbohydrate, and ethanol. HDL cholesterol levels in amenorrheic subjects correlated positively with the percent of dietary calories from fat (r = 0.42, n = 23, P = 0.045) but negatively with the percent from protein (r = -0.49, n = 23, P = 0.017). Thus, exercise-induced amenorrhea may adversely affect cardiovascular risk by increasing plasma LDL and total cholesterol. However, cardioprotective elevations in plasma HDL and HDL2 cholesterol may neutralize the risk of cardiovascular disease in amenorrheic athletes.

Comparison of soymilk and probiotic soymilk effects on serum high-density lipoprotein cholesterol and low-density lipoprotein cholesterol in diabetic Wistar rats

Directory of Open Access Journals (Sweden)

Mina Babashahi

2015-04-01

Full Text Available BACKGROUND: Soy milk (SM and its fermented products are identified as rich sources of bioactive compounds helping to manage and to reduce the risk of chronic disease. This study aimed to compare the effects of SM and probiotic SM (PSM consumption on serum low-density lipoprotein cholesterol (LDL-C and high-density lipoprotein cholesterol (HDL-C in diabetic Wistar rats. METHODS: Probiotic SM was prepared by fermentation of the plain SM with a native strain of Lactobacillus plantarum. 20 streptozotocin-nicotinamide-induced diabetic Wistar rats were divided into two groups based on the type of administered SM (SM group and PSM group. The animals were fed with 1 ml/day of either soy or PSM for 21 days. The serum lipoprotein levels were analyzed at baseline and the end of the intervention period. RESULTS: HDL-C increased significantly in PSM group. Furthermore, this group showed more percent of change in increased HDL-C in compression with SM group (P < 0.050. Regarding LDL-C level, rats fed with SM was not significantly different from the PSM group (P < 0.050; though, this biomarker was reduced in both group. CONCLUSION: Probiotic SM could modulate blood lipoprotein levels. Thus, it may be considered in managing diabetes complications and atherosclerotic risks. 

Enhancing Nanos expression via the bacterial TomO protein is a conserved strategy used by the symbiont Wolbachia to fuel germ stem cell maintenance in infected Drosophila females.

Science.gov (United States)

Ote, Manabu; Yamamoto, Daisuke

2018-04-27

The toxic manipulator of oogenesis (TomO) protein has been identified in the wMel strain of Wolbachia that symbioses with the vinegar fly Drosophila melanogaster, as a protein that affects host reproduction. TomO protects germ stem cells (GSCs) from degeneration, which otherwise occurs in ovaries of host females that are mutant for the gene Sex-lethal (Sxl). We isolated the TomO homologs from wPip, a Wolbachia strain from the mosquito Culex quinquefasciatus. One of the homologs, TomO w Pip 1, exerted the GSC rescue activity in fly Sxl mutants when lacking its hydrophobic stretches. The GSC-rescuing action of the TomO w Pip 1 variant was ascribable to its abilities to associate with Nanos (nos) mRNA and to enhance Nos protein expression. The analysis of structure-activity relationships with TomO homologs and TomO deletion variants revealed distinct modules in the protein that are each dedicated to different functions, i.e., subcellular localization, nos mRNA binding or Nos expression enhancement. We propose that modular reshuffling is the basis for structural and functional diversification of TomO protein members. © 2018 Wiley Periodicals, Inc.

A high-density lipoprotein-mediated drug delivery system.

Science.gov (United States)

Mo, Zhong-Cheng; Ren, Kun; Liu, Xing; Tang, Zhen-Li; Yi, Guang-Hui

2016-11-15

High-density lipoprotein (HDL) is a comparatively dense and small lipoprotein that can carry lipids as a multifunctional aggregate in plasma. Several studies have shown that increasing the levels or improving the functionality of HDL is a promising target for treating a wide variety of diseases. Among lipoproteins, HDL particles possess unique physicochemical properties, including naturally synthesized physiological components, amphipathic apolipoproteins, lipid-loading and hydrophobic agent-incorporating characteristics, specific protein-protein interactions, heterogeneity, nanoparticles, and smaller size. Recently, the feasibility and superiority of using HDL particles as drug delivery vehicles have been of great interest. In this review, we summarize the structure, constituents, biogenesis, remodeling, and reconstitution of HDL drug delivery systems, focusing on their delivery capability, characteristics, applications, manufacturing, and drug-loading and drug-targeting characteristics. Finally, the future prospects are presented regarding the clinical application and challenges of using HDL as a pharmacodelivery carrier. Copyright © 2016 Elsevier B.V. All rights reserved.

Serum amyloid A is found on ApoB-containing lipoproteins in obese humans with diabetes.

Science.gov (United States)

Jahangiri, Anisa; Wilson, Patricia G; Hou, Tianfei; Brown, Aparna; King, Victoria L; Tannock, Lisa R

2013-05-01

In murine models of obesity/diabetes, there is an increase in plasma serum amyloid A (SAA) levels along with redistribution of SAA from high-density lipoprotein (HDL) to apolipoprotein B (apoB)-containing lipoprotein particles, namely, low-density lipoprotein and very low-density lipoprotein. The goal of this study was to determine if obesity is associated with similar SAA lipoprotein redistribution in humans. Three groups of obese individuals were recruited from a weight loss clinic: healthy obese (n = 14), metabolic syndrome (MetS) obese (n = 8), and obese with type 2 diabetes (n = 6). Plasma was separated into lipoprotein fractions by fast protein liquid chromatography, and SAA was measured in lipid fractions using enzyme-linked immunosorbent assay and Western blotting. Only the obese diabetic group had SAA detectable in apoB-containing lipoproteins, and SAA reverted back to HDL with active weight loss. In human subjects, SAA is found in apoB-containing lipoprotein particles only in obese subjects with type 2 diabetes, but not in healthy obese or obese subjects with MetS. Copyright © 2012 The Obesity Society.

Peri and Postparturient Concentrations of Lipid Lipoprotein Insulin and Glucose in Normal Dairy Cows

OpenAIRE

BAŞOĞLU, Abdullah; SEVİNÇ, Mutlu; OK, Mahmut

1998-01-01

In order to provide uniqe insight into the metabolic disturbences seen after calving cholesterol, triglycerid, high density lipoprotein, low density lipoprotein, very low density lipoprotein, glucose and insulin levels in serum were studied before calving (group I), in aerly (group II) and late (group III) lactation in 24 normal cows. Serum lipoproteins were separeted into various density classes by repeated ultracentrifugation. The results indicate that there was a rise in glucose, trygl...

Small-Molecule Inhibitors of Gram-Negative Lipoprotein Trafficking Discovered by Phenotypic Screening

Science.gov (United States)

Fleming, Paul R.; MacCormack, Kathleen; McLaughlin, Robert E.; Whiteaker, James D.; Narita, Shin-ichiro; Mori, Makiko; Tokuda, Hajime; Miller, Alita A.

2015-01-01

In Gram-negative bacteria, lipoproteins are transported to the outer membrane by the Lol system. In this process, lipoproteins are released from the inner membrane by the ABC transporter LolCDE and passed to LolA, a diffusible periplasmic molecular chaperone. Lipoproteins are then transferred to the outer membrane receptor protein, LolB, for insertion in the outer membrane. Here we describe the discovery and characterization of novel pyridineimidazole compounds that inhibit this process. Escherichia coli mutants resistant to the pyridineimidazoles show no cross-resistance to other classes of antibiotics and map to either the LolC or LolE protein of the LolCDE transporter complex. The pyridineimidazoles were shown to inhibit the LolA-dependent release of the lipoprotein Lpp from E. coli spheroplasts. These results combined with bacterial cytological profiling are consistent with LolCDE-mediated disruption of lipoprotein targeting to the outer membrane as the mode of action of these pyridineimidazoles. The pyridineimidazoles are the first reported inhibitors of the LolCDE complex, a target which has never been exploited for therapeutic intervention. These compounds open the door to further interrogation of the outer membrane lipoprotein transport pathway as a target for antimicrobial therapy. PMID:25583975

Small-molecule inhibitors of gram-negative lipoprotein trafficking discovered by phenotypic screening.

Science.gov (United States)

McLeod, Sarah M; Fleming, Paul R; MacCormack, Kathleen; McLaughlin, Robert E; Whiteaker, James D; Narita, Shin-Ichiro; Mori, Makiko; Tokuda, Hajime; Miller, Alita A

2015-03-01

In Gram-negative bacteria, lipoproteins are transported to the outer membrane by the Lol system. In this process, lipoproteins are released from the inner membrane by the ABC transporter LolCDE and passed to LolA, a diffusible periplasmic molecular chaperone. Lipoproteins are then transferred to the outer membrane receptor protein, LolB, for insertion in the outer membrane. Here we describe the discovery and characterization of novel pyridineimidazole compounds that inhibit this process. Escherichia coli mutants resistant to the pyridineimidazoles show no cross-resistance to other classes of antibiotics and map to either the LolC or LolE protein of the LolCDE transporter complex. The pyridineimidazoles were shown to inhibit the LolA-dependent release of the lipoprotein Lpp from E. coli spheroplasts. These results combined with bacterial cytological profiling are consistent with LolCDE-mediated disruption of lipoprotein targeting to the outer membrane as the mode of action of these pyridineimidazoles. The pyridineimidazoles are the first reported inhibitors of the LolCDE complex, a target which has never been exploited for therapeutic intervention. These compounds open the door to further interrogation of the outer membrane lipoprotein transport pathway as a target for antimicrobial therapy. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Plasma lipoprotein(a) levels in patients with homozygous autosomal dominant hypercholesterolemia

NARCIS (Netherlands)

Sjouke, B.; Yahya, R.; Tanck, M.W.T.; Defesche, J.C.; Graaf, J. de; Wiegman, A.; Kastelein, J.J.; Mulder, M.T.; Hovingh, G.K.; Roeters van Lennep, J.E.

2017-01-01

BACKGROUND: Patients with autosomal dominant hypercholesterolemia (ADH), caused by mutations in either low-density lipoprotein receptor (LDLR), apolipoprotein B (APOB), or proprotein convertase subtilisin-kexin type 9 (PCSK9) are characterized by high low-density lipoprotein cholesterol levels and

Contact- and Protein Transfer-Dependent Stimulation of Assembly of the Gliding Motility Machinery in Myxococcus xanthus.

Directory of Open Access Journals (Sweden)

Beata Jakobczak

2015-07-01

Full Text Available Bacteria engage in contact-dependent activities to coordinate cellular activities that aid their survival. Cells of Myxococcus xanthus move over surfaces by means of type IV pili and gliding motility. Upon direct contact, cells physically exchange outer membrane (OM lipoproteins, and this transfer can rescue motility in mutants lacking lipoproteins required for motility. The mechanism of gliding motility and its stimulation by transferred OM lipoproteins remain poorly characterized. We investigated the function of CglC, GltB, GltA and GltC, all of which are required for gliding. We demonstrate that CglC is an OM lipoprotein, GltB and GltA are integral OM β-barrel proteins, and GltC is a soluble periplasmic protein. GltB and GltA are mutually stabilizing, and both are required to stabilize GltC, whereas CglC accumulate independently of GltB, GltA and GltC. Consistently, purified GltB, GltA and GltC proteins interact in all pair-wise combinations. Using active fluorescently-tagged fusion proteins, we demonstrate that GltB, GltA and GltC are integral components of the gliding motility complex. Incorporation of GltB and GltA into this complex depends on CglC and GltC as well as on the cytoplasmic AglZ protein and the inner membrane protein AglQ, both of which are components of the gliding motility complex. Conversely, incorporation of AglZ and AglQ into the gliding motility complex depends on CglC, GltB, GltA and GltC. Remarkably, physical transfer of the OM lipoprotein CglC to a ΔcglC recipient stimulates assembly of the gliding motility complex in the recipient likely by facilitating the OM integration of GltB and GltA. These data provide evidence that the gliding motility complex in M. xanthus includes OM proteins and suggest that this complex extends from the cytoplasm across the cell envelope to the OM. These data add assembly of gliding motility complexes in M. xanthus to the growing list of contact-dependent activities in bacteria.

Recent advances in lipoprotein and atherosclerosis: A nutrigenomic approach

OpenAIRE

López, Sergio; Ortega, Almudena; Varela, Lourdes; Bermúdez, Beatriz; Muriana, Francisco JG; Abia, Rocío

2009-01-01

Atherosclerosis is a disease in which multiple factors contribute to the degeneration of the vascular wall. Many risk factors have been identified as having influence on the progression of atherosclerosis among them, the type of diet. Multifactorial interaction among lipoproteins, vascular wall cells, and inflammatory mediators has been recognised as the basis of atherogenesis. Dietary intake affects lipoprotein concentration and composition providing risk or protection at several stages of a...

Plasma lipoprotein(a) levels in patients with homozygous autosomal dominant hypercholesterolemia

NARCIS (Netherlands)

Sjouke, Barbara; Yahya, Reyhana; Tanck, Michael W. T.; Defesche, Joep C.; de Graaf, Jacqueline; Wiegman, Albert; Kastelein, John J. P.; Mulder, Monique T.; Hovingh, G. Kees; Roeters van Lennep, Jeanine E.

2017-01-01

Patients with autosomal dominant hypercholesterolemia (ADH), caused by mutations in either low-density lipoprotein receptor (LDLR), apolipoprotein B (APOB), or proprotein convertase subtilisin-kexin type 9 (PCSK9) are characterized by high low-density lipoprotein cholesterol levels and in some

Obtention of scintillography images by low density lipoproteins labelled with technetium 99

International Nuclear Information System (INIS)

Silva, S.; Coelho, I.; Zanardo, E.; Pileggi, F.; Meneguethi, C.; Maranhao, R.C.

1992-01-01

The low density lipoproteins carry the most part of the cholesterol in the blood plasma. These lipoproteins are labelled with technetium-99-m and have been used for obtaining images in nuclear medicine. The introduction of this technique is presented, aiming futures clinical uses. Scintillographic images are obtained 25 minutes and 24 hours after the injection of 3 m Ci of low density lipoproteins - technetium-99 m in rabbits. (C.G.C.)

Lipoprotein (a) Management: Lifestyle and Hormones.

Science.gov (United States)

Garcia-Rios, Antonio; Leon-Acuna, Ana; Lopez-Miranda, Jose; Perez-Martinez, Pablo

2017-01-01

Cardiovascular disease (CVD) continues to be the first cause of mortality in developed countries. Moreover, far from diminishing, the cardiovascular risk factors leading towards the development of CVD are on the rise. Therefore, the preventive and therapeutic management which is currently in place is clearly not enough to stop this pandemic. In this context, a major resurgence in interest in lipoprotein (a) [Lp(a)] has occurred in light of its association with CVD. This series aims to review the basic and clinical aspects of Lp(a) biology. Specifically, the present review considers the current situation regarding the influence of lifestyle, hormones and other physiological or pathological conditions on Lp(a) plasma concentrations which might mitigate the harmful effects of this lipoprotein. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Effect of Ascorbic Acid on Lipoprotein Lipase Activity | Kotze | South ...

African Journals Online (AJOL)

Baboons kept on hypovitaminotic C diets, but without clinical signs of scurvy, had significantly higher heart muscle lipoprotein lipase activity than baboons on vitamin C 34 mg/kg body mass/day. When the serum vitamin C levels were above 0,35 mg/100 ml the heart muscle lipoprotein lipase was repressed. Serum vitamin C ...

Apolipoprotein B-containing lipoproteins and atherosclerotic cardiovascular disease [version 1; referees: 2 approved

Directory of Open Access Journals (Sweden)

Michael D. Shapiro

2017-02-01

Full Text Available Cholesterol-rich, apolipoprotein B (apoB-containing lipoproteins are now widely accepted as the most important causal agents of atherosclerotic cardiovascular disease. Multiple unequivocal and orthogonal lines of evidence all converge on low-density lipoprotein and related particles as being the principal actors in the genesis of atherosclerosis. Here, we review the fundamental role of atherogenic apoB-containing lipoproteins in cardiovascular disease and several other humoral and parietal factors that are required to initiate and maintain arterial degeneration. The biology of foam cells and their interactions with high-density lipoproteins, including cholesterol efflux, are also briefly reviewed.

Sorting of an integral outer membrane protein via the lipoprotein-specific Lol pathway and a dedicated lipoprotein pilotin.

Science.gov (United States)

Collin, Séverine; Guilvout, Ingrid; Nickerson, Nicholas N; Pugsley, Anthony P

2011-05-01

The lipoprotein PulS is a dedicated chaperone that is required to target the secretin PulD to the outer membrane in Klebsiella or Escherichia coli, and to protect it from proteolysis. Here, we present indirect evidence that PulD protomers do not assemble into the secretin dodecamer before they reach the outer membrane, and that PulS reaches the outer membrane in a soluble heterodimer with the general lipoprotein chaperone LolA. However, we could not find any direct evidence for PulD protomer association with the PulS-LolA heterodimer. Instead, in cells producing PulD and a permanently locked PulS-LolA dimer (in which LolA carries an R43L substitution that prevents lipoprotein transfer to LolB in the outer membrane), LolAR43L was found in the inner membrane, probably still associated with PulS bound to PulD that had been incorrectly targeted because of the LolAR43L substitution. It is speculated that PulD protomers normally cross the periplasm together with PulS bound to LolA but when the latter cannot be separated (due to the mutation in lolA), the PulD protomers form dodecamers that insert into the inner membrane. © 2011 Blackwell Publishing Ltd.

Lifecycle of a Lipoprotein from a Biophysical Perspective

Science.gov (United States)

Rutledge, John C.; Huser, Thomas; Voss, John; Chan, James; Parikh, Atul

The goal of our project was to understand how lipids and lipoproteins interact with cell membranes. This chapter will present the five major areas in which we have focused our attention on understanding how lipids and lipoproteins interact with cell membranes (Fig. 11.1): (1) triglycerides and vascular injury, (2) single lipoprotein analysis, (3) apolipoprotein E (apoE) conformation changes in the postprandial state, (4) triglyceride-rich lipoproteins (TGRLs) and endothelial cell inflammation, and (5) TGRL lipolysis products and monocyte activation. For over a hundred years, Western civilization has questioned how the food we eat translates into disease, and specifically atherosclerotic cardiovascular disease. Although most information indicates that this basic pathophysiological process is mediated through consumption of excess saturated fats, much remains unknown. After humans eat a meal, there is an elevation of triglycerides in the blood in the postprandial state. In normal individuals, triglycerides can rise after a meal by 50 to 100%. This has been documented many times in the past, including a paper by Hyson et al, (1998) [1]. In that study, normal healthy individuals were given a 40%-fat meal. Plasma triglycerides, which were modestly elevated initially, rose about 60% higher three to four hours after ingestion of the meal. Subsequently plasma triglycerides fell to baseline levels six hours after the meal. Even in these healthy individuals, a significant elevation of triglycerides was noted after ingestion of a moder ately high-fat meal.

Characteristics of 2,4,5,2',4',5'-hexachlorobiphenyl distribution among lipoproteins in vitro

International Nuclear Information System (INIS)

Vomachka, M.S.; Vodicnik, M.J.; Lech, J.J.

1983-01-01

The uptake, distribution, and transfer of 2,4,5,2',4',5'-hexachlorobiphenyl (6-CB) were examined in vitro with human and rat whole blood, plasma, and lipoprotein fractions. 6-CB distribution between plasma and erythrocytes as well as among lipoproteins was determined following sedimentation of erythrocytes and ultracentrifugal fractionation of plasma. In both rat and human whole blood, 70 to 75% of 6-CB partitioned into plasma and 25 to 30% into erythrocytes. The uptake of 6-CB into plasma was extremely rapid and the rate of uptake was found to be dependent upon temperature. The distribution of 6-CB among lipoproteins was relatively homogeneous with 20 to 30% being distributed in very low-density lipoproteins (VLDL, d . 0.95-1.006 g/ml), 15 to 20% in low-density lipoproteins (LDL, d . 1.006-1.063 g/ml), and 15 to 25% in high-density lipoproteins (HDL, d . 1.063-1.21 g/ml). Over 25% of 6-CB was found in the remaining bottom fraction. In addition, each isolated fraction when incubated alone with 6-CB was shown capable of uptake. The relative proportion of 6-CB among the lipoproteins was independent of the level taken up by plasma. 6-CB was also found to transfer among lipoproteins. This exchange of 6-CB proved to be dependent upon the concentrations of both protein and triacylglycerol in the incubations. Two proteins in the bottom fraction (Bf), albumin and a steroid binding globulin, were capable of competing with the lipoproteins for 6-CB uptake

High-density lipoproteins: a novel therapeutic target for cardiovascular disease

Directory of Open Access Journals (Sweden)

TS Mohamed Saleem

2011-01-01

Full Text Available TS Mohamed Saleem1, PV Sandhya Rani1, K Gauthaman21Department of Pharmacology, Annamacharya College of Pharmacy, New Boyanapalli, Andhrapradesh, India; 2Department of Drug Technology, Faculty of Medical Technology, Derna, LibyaAbstract: Cardiovascular disease has a high rate of mortality in both Western and developing countries. Atherosclerosis and generation of reactive oxygen species through oxidative stress is the major risk factor for cardiovascular disease. Atherothrombosis with low levels of high-density lipoprotein (HDL and high levels of low-density lipoprotein is a major risk factor for atherosclerosis-induced cardiovascular disease. Lipid-lowering drugs like statins, niacin, fibrates, and some newer agents, ie, the apolipoprotein A-I mimetics and the cholesteryl ester transfer protein inhibitors, not only increase HDL levels but are also effective in reducing key atherogenic lipid components, including triglyceride-rich lipoproteins. The aim of this review is to discuss the accumulating evidence suggesting that HDL possesses a diverse range of biological actions, and that increasing HDL levels by drug treatment may be beneficial in the prevention of cardiovascular disease.Keywords: cardiovascular disease, lipoproteins, statins, apolipoprotein, atherosclerosis

Pneumococcal lipoproteins involved in bacterial fitness, virulence, and immune evasion.

Science.gov (United States)

Kohler, Sylvia; Voß, Franziska; Gómez Mejia, Alejandro; Brown, Jeremy S; Hammerschmidt, Sven

2016-11-01

Streptococcus pneumoniae (pneumococcus) has evolved sophisticated strategies to survive in several niches within the human body either as a harmless commensal or as a serious pathogen causing a variety of diseases. The dynamic interaction between pneumococci and resident host cells during colonization of the upper respiratory tract and at the site of infection is critical for bacterial survival and the development of disease. Pneumococcal lipoproteins are peripherally anchored membrane proteins and have pivotal roles in bacterial fitness including envelope stability, cell division, nutrient acquisition, signal transduction, transport (as substrate-binding proteins of ABC transporter systems), resistance to oxidative stress and antibiotics, and protein folding. In addition, lipoproteins are directly involved in virulence-associated processes such as adhesion, colonization, and persistence through immune evasion. Conversely, lipoproteins are also targets for the host response both as ligands for toll-like receptors and as targets for acquired antibodies. This review summarizes the multifaceted roles of selected pneumococcal lipoproteins and how this knowledge can be exploited to combat pneumococcal infections. © 2016 Federation of European Biochemical Societies.

Glycation and glycoxidation of low-density lipoproteins by glucose and low-molecular mass aldehydes. Formation of modified and oxidized particles

DEFF Research Database (Denmark)

Knott, Heather M; Brown, Bronwyn E; Davies, Michael Jonathan

2003-01-01

by the adduction of glucose or species derived from glucose, such as low-molecular mass aldehydes, to proteins. These reactions can be nonoxidative (glycation) or oxidative (glycoxidation) and result in the conversion of low-density lipoproteins (LDL) to a form that is recognized by the scavenger receptors...... with glucose. These processes are rapid and unaffected by low concentrations of copper ions. In contrast, lipid and protein oxidation are slow processes and occur to a limited extent in the absence of added copper ions. No evidence was obtained for the stimulation of lipid or protein oxidation by glucose...... or methylglyoxal in the presence of copper ions, whereas glycolaldehyde stimulated such reactions to a modest extent. These results suggest that the earliest significant events in this system are metal ion-independent glycation (modification) of the protein component of LDL, whilst oxidative events (glycoxidation...

Transvascular lipoprotein transport in patients with chronic renal disease

DEFF Research Database (Denmark)

Jensen, Trine Krogsgaard; Nordestgaard, Børge Grønne; Feldt-Rasmussen, Bo

2004-01-01

BACKGROUND: While increased plasma cholesterol is a well-established cardiovascular risk factor in the general population, this is not so among patients with chronic renal disease. We hypothesized that the transvascular lipoprotein transport, in addition to the lipoprotein concentration in plasma......, determines the degree of atherosclerosis among patients with chronic renal disease. METHODS: We used an in vivo method for measurement of transvascular transport of low-density lipoprotein (LDL) in 21 patients with chronic renal disease and in 42 healthy control patients. Autologous 131-iodinated LDL...... was reinjected intravenously, and the 1-hour fractional escape rate was taken as index of transvascular transport. RESULTS: Transvascular LDL transport tended to be lower in patients with chronic renal disease than in healthy control patients [3.3 (95% CI 2.4-4.2) vs. 4.2 (3.7-4.2)%/hour; NS]. However...

Lipoprotein(a) as a cardiovascular risk factor: current status

DEFF Research Database (Denmark)

Nordestgaard, Børge G; Chapman, M John; Ray, Kausik

2010-01-01

The aims of the study were, first, to critically evaluate lipoprotein(a) [Lp(a)] as a cardiovascular risk factor and, second, to advise on screening for elevated plasma Lp(a), on desirable levels, and on therapeutic strategies.......The aims of the study were, first, to critically evaluate lipoprotein(a) [Lp(a)] as a cardiovascular risk factor and, second, to advise on screening for elevated plasma Lp(a), on desirable levels, and on therapeutic strategies....

Lipoprotein(a) and ischemic heart disease-A causal association? A review

DEFF Research Database (Denmark)

Kamstrup, P.R.

2010-01-01

association of LPA copy number variants, influencing levels of lipoprotein(a), with risk of IHD. In conclusion, results from epidemiologic, in vitro, animal, and genetic epidemiologic studies support a causal association of lipoprotein(a) with risk of IHD, while results from randomized clinical trials...

Defective Lipoprotein Sorting Induces lolA Expression through the Rcs Stress Response Phosphorelay System

OpenAIRE

Tao, Kazuyuki; Narita, Shin-ichiro; Tokuda, Hajime

2012-01-01

The Escherichia coli LolA protein is a lipoprotein-specific chaperone that carries lipoproteins from the inner to the outer membrane. A dominant negative LolA mutant, LolA(I93C/F140C), in which both 93Ile and 140Phe are replaced by Cys, binds tightly to the lipoprotein-dedicated ABC transporter LolCDE complex on the inner membrane and therefore inhibits the detachment of outer membrane-specific lipoproteins from the inner membrane. We found that the expression of this mutant strongly induced ...

High-Density Lipoproteins and the Immune System

Directory of Open Access Journals (Sweden)

Hidesuke Kaji

2013-01-01

Full Text Available High-density lipoprotein (HDL plays a major role in vasodilation and in the reduction of low-density lipoprotein (LDL oxidation, inflammation, apoptosis, thrombosis, and infection; however, HDL is now less functional in these roles under certain conditions. This paper focuses on HDL, its anti-inflammation behavior, and the mechanisms by which HDL interacts with components of the innate and adaptive immune systems. Genome-wide association studies (GWAS and proteomic studies have elucidated important molecules involved in the interaction between HDL and the immune system. An understanding of these mechanisms is expected to be useful for the prevention and treatment of chronic inflammation due to metabolic syndrome, atherosclerosis, or various autoimmune diseases.

Stimulation of LDL receptor activity in Hep-G2 cells by a serum factor(s)

International Nuclear Information System (INIS)

Ellsworth, J.L.; Brown, C.; Cooper, A.D.

1988-01-01

The regulation of low-density lipoprotein (LDL) receptor activity in the human hepatoma cell line Hep-G2 by serum components was examined. Incubation of dense monolayers of Hep-G2 cells with fresh medium containing 10% fetal calf serum (FM) produced a time-dependent increase in LDL receptor activity. Uptake and degradation of 125I-LDL was stimulated two- to four-fold, as compared with that of Hep-G2 cells cultured in the same media in which they had been grown to confluence (CM); the maximal 125I-LDL uptake plus degradation increased from 0.2 microgram/mg cell protein/4 h to 0.8 microgram/mg cell protein/4 h. In addition, a two-fold increase in cell surface binding of 125I-LDL to Hep-G2 cells was observed when binding was measured at 4 degrees C. There was no change in the apparent Kd. The stimulation of LDL receptor activity was suppressed in a concentration-dependent manner by the addition of cholesterol, as LDL, to the cell medium. In contrast to the stimulation of LDL receptor activity, FM did not affect the uptake or degradation of 125I-asialoorosomucoid. Addition of FM increased the protein content per dish, and DNA synthesis was stimulated approximately five-fold, as measured by [3H]thymidine incorporation into DNA; however, the cell number did not change. Cellular cholesterol biosynthesis was also stimulated by FM; [14C]acetate incorporation into unesterified and esterified cholesterol was increased approximately five-fold. Incubation of Hep-G2 cells with high-density lipoproteins (200 micrograms protein/ml) or albumin (8.0 mg/ml) in the absence of the serum factor did not significantly increase the total processed 125I-LDL. Stimulation of LDL receptor activity was dependent on a heat-stable, nondialyzable serum component that eluted in the inclusion volume of a Sephadex G-75 column

Apolipoprotein(a) phenotypes and lipoprotein(a) concentrations in patients with hyperthyroidism

DEFF Research Database (Denmark)

Klausen, I C; Hegedüs, L; Hansen, P S

1995-01-01

Lipoprotein(a) [Lp(a)] is a low-density lipoprotein (LDL) particle in which apolipoprotein B-100 (apoB) is attached to a glycoprotein called apolipoprotein(a) [apo(a)]. Apo(a) has several genetically determined phenotypes differing in molecular weight, to which Lp(a) concentrations in plasma are ...

Increased transvascular lipoprotein transport in diabetes

DEFF Research Database (Denmark)

Jensen, Jan Skov; Feldt-Rasmussen, Bo; Borch-Johnsen, Knut

2005-01-01

CONTEXT: Diabetes is associated with a highly increased risk of atherosclerosis, especially if hypertension or albuminuria is present. OBJECTIVE: We hypothesized that the increased transvascular lipoprotein transport in diabetes may be further accelerated if hypertension or albuminuria is present...... of transvascular transport. RESULTS: Transvascular LDL transport was 1.8 (1.6-2.0), 2.3 (2.0-2.6), and 2.6 (1.3-4.0)%/[h x (liter/m2)] in healthy controls, diabetic controls, and diabetes patients with systolic hypertension or albuminuria, respectively (P = 0.013; F = 4.5; df =2; ANOVA). These differences most...... likely were not caused by altered hepatic LDL receptor expression, glycosylation of LDL, small LDL size, or medicine use. CONCLUSIONS: Transvascular LDL transport is increased in patients with diabetes mellitus, especially if systolic hypertension or albuminuria is present. Accordingly, lipoprotein flux...

Hepatic apo B-100 lipoproteins and plasma LDL heterogeneity in African green monkeys

International Nuclear Information System (INIS)

Murthy, V.N.; Marzetta, C.A.; Rudel, L.L.; Zech, L.A.; Foster, D.M.

1990-01-01

The contribution of hepatic apolipoprotein (apo) B-100 lipoproteins to plasma low-density lipoprotein (LDL) metabolic heterogeneity was examined in African green monkeys. Hepatic 3H-labeled very low-density lipoproteins (VLDL) (d less than 1.006, where d is density in g/ml) or hepatic 131I-labeled LDL (1.030 less than d less than 1.063) were isolated from perfused livers and injected simultaneously with autologous plasma 125I-LDL into African green monkeys. Serial blood samples were taken, and the distribution of radioactivity among various subfractions of apo B-100 lipoproteins was determined using density-gradient ultracentrifugation. Compartmental models were developed to describe simultaneously the kinetics of hepatic lipoproteins and plasma LDL. In five of seven studies, the metabolic behavior of LDL derived from radiolabeled hepatic lipoprotein precursors differed from the metabolic behavior of radiolabeled autologous plasma LDL. These differences could be described by different models supporting two hypotheses with different physiological interpretations: (1) lipoproteins of donor and recipient animals are kinetically distinct, and/or (2) plasma LDL derived from various potential sources are kinetically distinct. Compartmental modeling was used to test these hypotheses, which were not accessible to testing by conventional experimental methodologies. The kinetic analyses of these studies suggest that plasma LDL may be derived from a variety of precursors, including hepatic VLDL and hepatic LDL, with each source giving rise to metabolically distinct plasma LDL

Effects of Anabolic Steroids on Lipoprotein Profiles of Female Weight Lifters.

Science.gov (United States)

Moffatt, Robert J.; And Others

1990-01-01

This study examined the effects of resistance exercise and anabolic steroids on lipoprotein profiles of female weightlifters. The study found that women who participate in resistance training have better lipoprotein profiles than their sedentary counterparts, but these changes do not offset the deleterious effects of steroid use. (SM)

The effect of interaction between Lipoprotein Lipase and ApoVLDL-II ...

African Journals Online (AJOL)

Body weight, abdominal fat weight and serum biochemical levels were determined from lean and fat chicken breeds at 12 weeks of age. Single nucleotide polymorphism (SNP) in apoVLDL-II and lipoprotein lipase genes was screened by PCR-SSCP and detected by direct sequencing. Lipoprotein lipase gene frequency ...

Triglyceride content in remnant lipoproteins is significantly increased after food intake and is associated with plasma lipoprotein lipase.

Science.gov (United States)

Nakajima, Katsuyuki; Tokita, Yoshiharu; Sakamaki, Koji; Shimomura, Younosuke; Kobayashi, Junji; Kamachi, Keiko; Tanaka, Akira; Stanhope, Kimber L; Havel, Peter J; Wang, Tao; Machida, Tetsuo; Murakami, Masami

2017-02-01

Previous large population studies reported that non-fasting plasma triglyceride (TG) reflect a higher risk for cardiovascular disease than TG in the fasting plasma. This is suggestive of the presence of higher concentration of remnant lipoproteins (RLP) in postprandial plasma. TG and RLP-TG together with other lipids, lipoproteins and lipoprotein lipase (LPL) in both fasting and postprandial plasma were determined in generally healthy volunteers and in patients with coronary artery disease (CAD) after consuming a fat load or a more typical moderate meal. RLP-TG/TG ratio (concentration) and RLP-TG/RLP-C ratio (particle size) were significantly increased in the postprandial plasma of both healthy controls and CAD patients compared with those in fasting plasma. LPL/RLP-TG ratio demonstrated the interaction correlation between RLP concentration and LPL activity The increased RLP-TG after fat consumption contributed to approximately 90% of the increased plasma TG, while approximately 60% after a typical meal. Plasma LPL in postprandial plasma was not significantly altered after either type of meal. Concentrations of RLP-TG found in the TG along with its particle size are significantly increased in postprandial plasma compared with fasting plasma. Therefore, non-fasting TG determination better reflects the presence of higher RLP concentrations in plasma. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

Characterization of Two Metal Binding Lipoproteins as Vaccine Candidates for Enterococcal Infections.

Science.gov (United States)

Romero-Saavedra, Felipe; Laverde, Diana; Budin-Verneuil, Aurélie; Muller, Cécile; Bernay, Benoit; Benachour, Abdellah; Hartke, Axel; Huebner, Johannes

2015-01-01

Enterococcus faecium and faecalis are Gram-positive opportunistic pathogens that have become leading causes of nosocomial infections over the last decades. Especially multidrug resistant enterococci have become a challenging clinical problem worldwide. Therefore, new treatment options are needed and the identification of alternative targets for vaccine development has emerged as a feasible alternative to fight the infections caused by these pathogens. We extrapolate the transcriptomic data from a mice peritonitis infection model in E. faecalis to identify putative up-regulated surface proteins under infection conditions in E. faecium. After the bionformatic analyses two metal binding lipoproteins were identified to have a high homology (>72%) between the two species, the manganese ABC transporter substrate-binding lipoprotein (PsaAfm,) and the zinc ABC transporter substrate-binding lipoprotein (AdcAfm). These candidate lipoproteins were overexpressed in Escherichia coli and purified. The recombinant proteins were used to produce rabbit polyclonal antibodies that were able to induce specific opsonic antibodies that mediated killing of the homologous strain E. faecium E155 as well as clinical strains E. faecium E1162, Enterococcus faecalis 12030, type 2 and type 5. Mice were passively immunized with the antibodies raised against recombinant lipoproteins, showing significant reduction of colony counts in mice livers after the bacterial challenge and demonstrating the efficacy of these metal binding lipoproteins as promising vaccine candidates to treat infections caused by these enterococcal pathogens. Overall, our results demonstrate that these two metal binding lipoproteins elicited specific, opsonic and protective antibodies, with an extensive cross-reactivity and serotype-independent coverage among these two important nocosomial pathogens. Pointing these two protein antigens as promising immunogens, that can be used as single components or as carrier proteins

Association of mitotane with chylomicrons and serum lipoproteins: practical implications for treatment of adrenocortical carcinoma.

Science.gov (United States)

Kroiss, Matthias; Plonné, Dietmar; Kendl, Sabine; Schirmer, Diana; Ronchi, Cristina L; Schirbel, Andreas; Zink, Martina; Lapa, Constantin; Klinker, Hartwig; Fassnacht, Martin; Heinz, Werner; Sbiera, Silviu

2016-03-01

Oral mitotane (o,p'-DDD) is a cornerstone of medical treatment for adrenocortical carcinoma (ACC). Serum mitotane concentrations >14  mg/l are targeted for improved efficacy but not achieved in about half of patients. Here we aimed at a better understanding of intestinal absorption and lipoprotein association of mitotane and metabolites o,p'-dichlorodiphenylacetic acid (o,p'-DDA) and o,p'-dichlorodiphenyldichloroethane (o,p'-DDE). Lipoproteins were isolated by ultracentrifugation from the chyle of a 29-year-old patient and serum from additional 14 ACC patients treated with mitotane. HPLC was applied for quantification of mitotane and metabolites. We assessed NCI-H295 cell viability, cortisol production, and expression of endoplasmic reticulum (ER) stress marker genes to study the functional consequences of mitotane binding to lipoproteins. Chyle of the index patient contained 197  mg/ml mitotane, 53  mg/ml o,p'-DDA, and 51  mg/l o,p'-DDE. Of the total mitotane in serum, lipoprotein fractions contained 21.7±21.4% (VLDL), 1.9±0.8% (IDL), 8.9±5.5% (LDL1), 18.9±9.6% (LDL2), 10.1±4.0% (LDL3), and 26.3±13.0% (HDL2). Only 12.3±5.5% were in the lipoprotein-depleted fraction. Mitotane content of lipoproteins directly correlated with their triglyceride and cholesterol content. O,p'-DDE was similarly distributed, but 87.9±4.2% of o,p'-DDA found in the HDL2 and lipoprotein-depleted fractions. Binding of mitotane to human lipoproteins blunted its anti-proliferative and anti-hormonal effects on NCI-H295 cells and reduced ER stress marker gene expression. Mitotane absorption involves chylomicron binding. High concentrations of o,p'-DDA and o,p'-DDE in chyle suggest intestinal mitotane metabolism. In serum, the majority of mitotane is bound to lipoproteins. In vitro, lipoprotein binding inhibits activity of mitotane suggesting that lipoprotein-free mitotane is the therapeutically active fraction. © 2016 European Society of Endocrinology.

Alterations in plasma lipoproteins and apolipoproteins before the age of 40 in heterozygotes for lipoprotein lipase deficiency

NARCIS (Netherlands)

Bijvoet, S.; Gagné, S. E.; Moorjani, S.; Gagné, C.; Henderson, H. E.; Fruchart, J. C.; Dallongeville, J.; Alaupovic, P.; Prins, M. [=Martin H.; Kastelein, J. J.; Hayden, M. R.

1996-01-01

We have assessed the expression of heterozygosity for lipoprotein lipase (LPL) deficiency by studying a single large French Canadian family comprising 92 persons including 21 carriers of the catalytically defective P207L mutation. Phenotypic changes distinguishing heterozygotes from controls were

The infective larva of Litomosoides yutajensis Guerrero et al., 2003 (Nematoda: Onchocercidae, a Wolbachia-free filaria from bat

Directory of Open Access Journals (Sweden)

Guerrero R.

2006-06-01

Full Text Available The infective larva of Litomosoides yutajensis Guerrero et al., 2003, a parasite of the bat Pteronotus parnellii, is described; it is distinct from congeneric infective larvae by the absence of caudal lappets. The life cycles of five other species of Litomosoides are known; three are parasites of rodents, one of a marsupial and one of a bat. As with these species, the experimental vector of L. yutajensis used was the macronyssid mite Ornithonyssus bacoti. In nature, the main vectors are probably other macronyssids but transmission by O. bacoti, with its large host-range, could account for the characteristic host-switchings in the evolution of Litomosoides. Unlike the murine model L. sigmodontis Chandler, 1931, L. yutajensis is devoid of the endosymbiontic bacteria Wolbachia and may be of great interest.

Interaction of estradiol and high density lipoproteins on proliferation of the human breast cancer cell line MCF-7 adapted to grow in serum free conditions

International Nuclear Information System (INIS)

Jozan, S.; Faye, J.C.; Tournier, J.F.; Tauber, J.P.; David, J.F.; Bayard, F.

1985-01-01

The responsiveness of the human mammary carcinoma cell line MCF-7 to estradiol and tamoxifen treatment has been studied in different culture conditions. Cells from exponentially growing cultures were compared with cells in their initial cycles after replating from confluent cultures (''confluent-log'' cells). It has been observed that estradiol stimulation of tritiated thymidine incorporation decreases with cell density and that ''confluent-log'' cells are estrogen unresponsive for a period of four cell cycles in serum-free medium conditions. On the other hand, growth of cells replated from exponentially growing, as well as from confluent cultures, can be inhibited by tamoxifen or a combined treatment with tamoxifen and the progestin levonorgestrel. This growth inhibitory effect can be rescued by estradiol when cells are replated from exponentially growing cultures. The growth inhibitory effect cannot be rescued by estradiol alone (10(-10) to 10(-8) M) when cells are replated from confluent cultures. In this condition, the addition of steroid depleted serum is necessary to reverse the state of estradiol unresponsiveness. Serum can be replaced by high density lipoproteins but not by low density lipoproteins or lipoprotein deficient serum. The present data show that estradiol and HDL interact in the control of MCF-7 cell proliferation

First WHO/IFCC International Reference Reagent for Lipoprotein(a) for Immunoassay--Lp(a) SRM 2B.

Science.gov (United States)

Dati, Francesco; Tate, Jillian R; Marcovina, Santica M; Steinmetz, Armin

2004-01-01

Lipoprotein(a) is an important predictor of cardiovascular disease risk. The lack of internationally accepted standardization has impeded the broad application of this lipoprotein in laboratory medicine. The International Federation of Clinical Chemistry and Laboratory Medicine (IFCC), through its Working Group on Lipoprotein(a) and together with research institutions and several diagnostic companies, have succeeded in developing an international reference material that is intended for the transfer of a lipoprotein(a) concentration to manufacturers' master calibrators. IFCC SRM 2B has recently been accepted by the WHO Expert Committee on Biological Standardization as the 'First WHO/IFCC International Reference Reagent for Lipoprotein(a) for Immunoassay'. The assigned unitage of 0.1071 nanomoles of lipoprotein(a) per vial is traceable to the consensus reference method for lipoprotein(a) and will enable conformity by diagnostic companies to the European Union's Directive on In vitro Diagnostic Medical Devices for the metrological traceability of calibrator materials.

Accumulation of native and methylated low density lipoproteins by healing rabbit arterial wall

International Nuclear Information System (INIS)

Fischman, A.J.; Lees, A.M.; Lees, R.S.; Barlai-Kovach, M.; Strauss, H.W.

1987-01-01

To determine whether healing arterial wall accumulation of low density lipoproteins (LDL) is mediated by the high affinity LDL receptor, normocholesterolemic rabbits were injected with 125 I-LDL, /sup 99m/Tc-LDL, or the reductively methylated analogs of these compounds ( 125 I-MeLDL, /sup 99m/Tc-MeLDL), 1 month after balloon catheter deendothelialization of the abdominal aorta. If the mechanism of accumulation requires interaction with the LDL receptor, reductively methylated lipoproteins which do not bind to the receptor should not accumulate in healing arterial wall. Twenty-four hours after injection of labelled lipoproteins, each animal was injected with Evans blue dye, in order to distinguish reendothelialized from deendothelialized aorta. One hour after dye injection, the aorta was fixed, removed, divided into abdominal (ballooned) and thoracic (unballooned) regions and counted. For all lipoprotein preparations, there were three to four times as many counts in the abdominal as in the thoracic aorta. En face autoradiographs were made of the aortas that had been exposed to 125 I-labelled lipoproteins. In the autoradiographs, the areas of the lowest activity corresponded to the centers of healing endothelial islands. The most intense radioactivity for both lipoproteins occurred in the region of the leading edge of the endothelial islands where active endothelial regeneration was in progress. The overall distribution of native and MeLDL accumulation was the same. The results suggest that low density lipoproteins are accumulated in areas of active endothelial regeneration by a mechanism that does not involve the high affinity LDL receptor

Lipoprotein distribution and serum concentrations of 7α-hydroxy-4-cholesten-3-one and bile acids: effects of monogenic disturbances in high-density lipoprotein metabolism

DEFF Research Database (Denmark)

Steiner, Carine; Holleboom, Adriaan G; Karuna, Ratna

2012-01-01

BA (bile acid) formation is considered an important final step in RCT (reverse cholesterol transport). HDL (high-density lipoprotein) has been reported to transport BAs. We therefore investigated the effects of monogenic disturbances in human HDL metabolism on serum concentrations and lipoprotein...... concentrations of conjugated and secondary BAs differed between heterozygous carriers of SCARB1 (scavenger receptor class B1) mutations and unaffected individuals (P...

Formation of tissue factor activity following incubation of recombinant human tissue factor apoprotein with plasma lipoproteins

International Nuclear Information System (INIS)

Sakai, T.; Kisiel, W.

1990-01-01

Incubation of recombinant human tissue factor apoprotein (Apo-TF) with human plasma decreased the recalcified clotting time of this plasma in a time-and dose-dependent manner suggesting relipidation of the Apo-TF by plasma lipoproteins. Incubation of Apo-TF with purified preparations of human very low density, low density and high density lipoproteins resulted in tissue factor activity in a clotting assay. The order of effectiveness was VLDL greater than LDL much greater than HDL. Tissue factor activity generated by incubation of a fixed amount of Apo-TF with plasma lipoproteins was lipoprotein concentration-dependent and saturable. The association of Apo-TF with lipoprotein particles was supported by gel filtration studies in which 125 I-Apo-TF coeluted with the plasma lipoprotein in the void volume of a Superose 6 column in the presence and absence of calcium ions. In addition, void-volume Apo-TF-lipoprotein fractions exhibited tissue factor activity. These results suggest that the factor VIII-bypassing activity of bovine Apo-TF observed in a canine hemophilic model may be due, in part, to its association with plasma lipoproteins and expression of functional tissue factor activity

Genes encoding two lipoproteins in the leuS-dacA region of the Escherichia coli chromosome

International Nuclear Information System (INIS)

Takase, I.; Ishino, F.; Wachi, M.; Kamata, H.; Doi, M.; Asoh, S.; Matsuzawa, H.; Ohta, T.; Matsuhashi, M.

1987-01-01

The coding of two rare lipoproteins by two genes, rlpA and rlpB, located in the leuS-dacA region (15 min) on the Escherichia coli chromosome was demonstrated by expression of subcloned genes in a maxicell system. The formation of these two proteins was inhibited by globomycin, which is an inhibitor of the signal peptidase for the known lipoproteins of E. coli. In each case, this inhibition was accompanied by formation of a new protein, which showed a slightly lower mobility on sodium dodecyl sulfate-polyacrylamide gel electrophoresis and which we suppose to be a prolipoprotein with an N-terminal signal peptide sequence similar to those of the bacterial major lipoproteins and lysis proteins of some bacteriocins. The incorporation of 3 H-labeled palmitate and glycerol into the two lipoproteins was also observed. Sequencing of DNA showed that the two lipoprotein genes contained sequences that could code for signal peptide sequences of 17 amino acids (rlpA lipoprotein) and 18 amino acids (rlpB lipoprotein). The deduced sequences of the mature peptides consisted of 345 amino acids (M/sub r/ 35,615, rlpA lipoprotein) and 175 amino acids (M/sub r/ 19,445, rlpB lipoprotein), with an N-terminal cysteine to which thioglyceride and N-fatty acyl residues may be attached. These two lioproteins may be important in duplication of the cells

Increased fluidity and oxidation of malarial lipoproteins: relation with severity and induction of endothelial expression of adhesion molecules

Directory of Open Access Journals (Sweden)

Looareesuwan Sornchai

2004-06-01

Full Text Available Abstract Introduction Oxidative stress has been demonstrated in malaria. The potential oxidative modification of lipoproteins derived from malaria patients was studied. These oxidized lipids may have role in pathogenesis of malaria. Method The plasma lipid profile and existence of oxidized forms of very low density lipoprotein (VLDL, low density lipoprotein (LDL and high density lipoprotein (HDL were investigated in malaria (17 mild and 24 severe patients and 37 control subjects. Thiobarbituric acid reactive substances (TBARs, conjugated dienes, tryptophan fluorescence and fluidity of lipoproteins were determined as markers of oxidation. The biological effect of malarial lipoproteins was assessed by the expression of adhesion molecules on endothelial cells. Results Malarial lipoproteins had decreased cholesterol (except in VLDL and phospholipid. The triglyceride levels were unchanged. The cholesterol/phospholipid ratio of LDL was decreased in malaria, but increased in VLDL and HDL. TBARs and conjugate dienes were increased in malarial lipoproteins, while the tryptophan fluorescence was decreased. The fluidity of lipoproteins was increased in malaria. These indicated the presence of oxidized lipoproteins in malaria by which the degree of oxidation was correlated with severity. Of three lipoproteins from malarial patients, LDL displayed the most pronounced oxidative modification. In addition, oxidized LDL from malaria patients increased endothelial expression of adhesion molecules. Conclusion In malaria, the lipoproteins are oxidatively modified, and the degree of oxidation is related with severity. Oxidized LDL from malarial patients increases the endothelial expression of adhesion molecules. These suggest the role of oxidized lipoproteins, especially LDL, on the pathogenesis of disease.

Changes in lipids and lipoprotein particle concentrations after interruption of antiretroviral therapy

DEFF Research Database (Denmark)

Lampe, Fiona C; Duprez, Daniel A; Kuller, Lewis H

2010-01-01

The effect of interruption of antiretroviral therapy (ART) on lipoprotein particle subclasses has not been studied. We examined short-term changes in lipids and lipoprotein particles among 332 HIV-infected individuals randomized to interrupt or continue ART in the "Strategies for Management...

Genetic diversity of Wolbachia endosymbionts in Culex quinquefasciatus from Hawai`i, Midway Atoll, and Samoa

Science.gov (United States)

Atkinson, Carter T.; Watcher-Weatherwax, William; Lapointe, Dennis

2016-01-01

Incompatible insect techniques are potential methods for controlling Culex quinquefasciatus and avian disease transmission in Hawai‘i without the use of pesticides or genetically modified organisms. The approach is based on naturally occurring sperm-egg incompatibilities within the Culex pipiens complex that are controlled by different strains of the bacterial endosymbiont Wolbachia pipientis (wPip). Incompatibilities can be unidirectional (crosses between males infected with strain A and females infected with strain B are fertile, while reciprocal crosses are not) or bidirectional (reciprocal crosses between sexes with different wPip strains are infertile). The technique depends on release of sufficient numbers of male mosquitoes infected with an incompatible wPip strain to suppress mosquito populations and reduce transmission of introduced avian malaria (Plasmodium relictum) and Avipoxvirus in native forest bird habitats. Both diseases are difficult to manage using more traditional methods based on removal and treatment of larval habitats and coordination of multiple approaches may be needed to control this vector. We characterized the diversity of Wolbachia strains in C. quinquefasciatus from Hawai‘i, Kaua‘i, Midway Atoll, and American Samoa with a variety of genetic markers to identify compatibility groups and their distribution within and between islands. We confirmed the presence of wPip with multilocus sequence typing, tested for local genetic variability using 16 WO prophage genes, and identified similarities to strains from other parts of the world with a transposable element (tr1). We also tested for genetic differences in ankyrin motifs (ank2 and pk1) which have been used to classify wPip strains into five worldwide groups (wPip1–wPip5) that vary in compatibility with each other based on experimental crosses. We found a mixture of both widely distributed and site specific genotypes based on presence or absence of WO prophage and transposable

Serum Sialic Acid Concentration and Content in ApoB-Containing Lipoproteins in Liver Diseases.

Science.gov (United States)

Gudowska, Monika; Gruszewska, Ewa; Cylwik, Bogdan; Panasiuk, Anatol; Filisiak, Robert; Szmitkowski, Maciej; Chrostek, Lech

2016-01-01

The great significance for the metabolism of lipoproteins is the composition of carbohydrate chain of apolipoproteins, where sialic acid (SA) is located. In VILDL and LDL sialic acid is attached to apolipoprotein B. The sialylation of serum proteins including apolipoprotein B can be affected in the course of liver diseases. Therefore, the aim of this study was to assess the effect of liver diseases on the concentration and content of SA in ApoB-containing lipoproteins. The tested group consisted of 165 patients (118 males, 47 females) with liver diseases: alcoholic cirrhosis, non-alcoholic cirrhosis, chronic hepatitis, toxic hepatitis, chronic viral hepatitis, and liver cancer. ApoB-containing lipoproteins were isolated by a turbidimetric procedure and SA concentration was measured according to an enzymatic method. There was a significant increase in the serum concentration of SA in ApoB-containing lipoproteins in viral hepatitis. Although the serum concentration of ApoB was not significantly different between specific liver diseases, the serum levels of SA in ApoB-containing lipoproteins appeared to be different. There is an association between SA concentration and triglycerides in alcoholic cirrhosis and viral hepatitis. Also, in viral hepatitis SA concentration correlated negatively with HDL-cholesterol. The content of SA in ApoB-containing lipoproteins in alcoholic cirrhosis and viral hepatitis was significantly higher than that in the control group, but did not differ between diseases. This study may explain the variations in serum lipids and lipoproteins in liver diseases. It seems that the reason for these abnormalities is the changes in the concentration of sialic acid in ApoB-containing lipoproteins.

[Residual risk: The roles of triglycerides and high density lipoproteins].

Science.gov (United States)

Grammer, Tanja; Kleber, Marcus; Silbernagel, Günther; Scharnagl, Hubert; März, Winfried

2016-06-01