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Query: UMLS:C0042109 (urticaria)
 6,569 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The skin is a common target of cellular and/or antibody mediated pathological immune responses. Pemphigoids, pemphigus vulgaris and dermatitis herpetiformis are bullous disease due to autoantibodies targeting specific proteins of the skin. The pemphigoid autoantigens are the BP180 and the BP230 antigens, two components of the epithelial basement membrane zone. Additional antigenic targets reported in a portion of patients are laminin 5, the alpha6 subunit of the hemidesmosomal integrin alpha6beta4 and a glycoprotein termed p200. The epidermal and mucosal epithelial cells detachment (acantholysis) characteristic of pemphigus vulgaris is induced by autoantibodies directed against the desmoglein 3 and 1. The desmogleins are desmosomal cadherins, which play a major role in the cell-to-cell adhesion. Dermatitis herpetiformis is regarded as cutaneous phenotype of coeliac disease. A novel autoimmune hypothesis of coeliac disease links wheat gliadin and tissue transglutaminase (TG2) in the gut, which leads to T cell response and IgA autoantibody formation. In dermatitis herpetiformis skin the target for IgA deposition seems to be epidermal TG3. Urticaria is a complex syndrome caused by both immune and non-immune mechanisms. In a subsets of patients with chronic urticaria mast cell degranulation is induced by autoantibodies directed against the a-subunit of the high-affinity IgE receptor, and/or the IgE.
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PMID:New insights into the autoantibody-mediated mechanisms of autoimmune bullous diseases and urticaria. 1646 21

The influence of geographic location, season, age, and part of the digestive tract on bacterial diversity was evaluated on intestinal microflora of honeybees, wasps, and cockroaches using DGGE analysis. PCR-DGGE analyses with universal bacterial primers targeting 200-bp region of the 16S rDNA gene afforded the profile of complex bacterial DNA; specific primers were used to determine the profile of bifidobacteria whose concentration in digestive tract was determined by real-time PCR. Selected PCR products were identified by sequencing. The microflora of the bees exhibited little variations among the hives from distant locations. Their bifidobacterial population formed 2.8-8.4 % of total bacteria and was very homogeneous. The total gut microflora of wasps was also homogeneous, only two samples being affected by the season or the location; on the other hand, wasp bifidobacterial population was very heterogeneous. Cockroaches showed the highest variations in microflora composition, the age and diet being the ultimate factors; bifidobacteria counts also varied among tested individuals (0.1-34.1 % of total bacteria). Our results suggest that nutrition habits are the strongest factor affecting the insect microflora, giving higher variations to omnivorous species.
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PMID:Diversity of insect intestinal microflora. 1866 Dec 98

Food allergy is a frequent problem in childhood and its prevalence is increasing. In most cases food allergy is an IgE-mediated hypersensitivity response that cause skin reactions as urticaria. Subacute or chronic disorders have generally a not IgE mediated mechanism. Milk is the most common food allergen in USA and UK followed by egg, peanut and walnuts. Sensitization to milk or egg in infancy is associated with an increased risk to develop house dust mite sensitization and asthma later in childhood. Commensal gut flora play a role in induction of oral tolerance and the importance of the intestinal microbiota in the development of food allergy is essential in early ages, when the mucosal barrier and immune system are still immature. Probiotics interact with the mucosal immune system by the same pathways as commensal bacteria. Recent study show that probiotic bacteria induced in vivo increased plasma levels IL-10 and total IgA in children with allergic predisposition. Many clinical studies reporting significant benefits by probiotics supplementation in food allergy prevention and management but not everyone agree on their effectiveness. These differences are probably related to differences in selected populations and in probiotic strains used.
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PMID:Food allergy and probiotics in childhood. 2056 32

Global pollinator declines have been attributed to habitat destruction, pesticide use, and climate change or some combination of these factors, and managed honey bees, Apis mellifera, are part of worldwide pollinator declines. Here we exposed honey bee colonies during three brood generations to sub-lethal doses of a widely used pesticide, imidacloprid, and then subsequently challenged newly emerged bees with the gut parasite, Nosema spp. The pesticide dosages used were below levels demonstrated to cause effects on longevity or foraging in adult honey bees. Nosema infections increased significantly in the bees from pesticide-treated hives when compared to bees from control hives demonstrating an indirect effect of pesticides on pathogen growth in honey bees. We clearly demonstrate an increase in pathogen growth within individual bees reared in colonies exposed to one of the most widely used pesticides worldwide, imidacloprid, at below levels considered harmful to bees. The finding that individual bees with undetectable levels of the target pesticide, after being reared in a sub-lethal pesticide environment within the colony, had higher Nosema is significant. Interactions between pesticides and pathogens could be a major contributor to increased mortality of honey bee colonies, including colony collapse disorder, and other pollinator declines worldwide.
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PMID:Pesticide exposure in honey bees results in increased levels of the gut pathogen Nosema. 2224 49

Recent losses in honey bee colonies are unusual in their severity, geographical distribution, and, in some cases, failure to present recognized characteristics of known disease. Domesticated honey bees face numerous pests and pathogens, tempting hypotheses that colony collapses arise from exposure to new or resurgent pathogens. Here we explore the incidence and abundance of currently known honey bee pathogens in colonies suffering from Colony Collapse Disorder (CCD), otherwise weak colonies, and strong colonies from across the United States. Although pathogen identities differed between the eastern and western United States, there was a greater incidence and abundance of pathogens in CCD colonies. Pathogen loads were highly covariant in CCD but not control hives, suggesting that CCD colonies rapidly become susceptible to a diverse set of pathogens, or that co-infections can act synergistically to produce the rapid depletion of workers that characterizes the disorder. We also tested workers from a CCD-free apiary to confirm that significant positive correlations among pathogen loads can develop at the level of individual bees and not merely as a secondary effect of CCD. This observation and other recent data highlight pathogen interactions as important components of bee disease. Finally, we used deep RNA sequencing to further characterize microbial diversity in CCD and non-CCD hives. We identified novel strains of the recently described Lake Sinai viruses (LSV) and found evidence of a shift in gut bacterial composition that may be a biomarker of CCD. The results are discussed with respect to host-parasite interactions and other environmental stressors of honey bees.
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PMID:Pathogen webs in collapsing honey bee colonies. 2292 91

Recent declines in honey bee populations and increasing demand for insect-pollinated crops raise concerns about pollinator shortages. Pesticide exposure and pathogens may interact to have strong negative effects on managed honey bee colonies. Such findings are of great concern given the large numbers and high levels of pesticides found in honey bee colonies. Thus it is crucial to determine how field-relevant combinations and loads of pesticides affect bee health. We collected pollen from bee hives in seven major crops to determine 1) what types of pesticides bees are exposed to when rented for pollination of various crops and 2) how field-relevant pesticide blends affect bees' susceptibility to the gut parasite Nosema ceranae. Our samples represent pollen collected by foragers for use by the colony, and do not necessarily indicate foragers' roles as pollinators. In blueberry, cranberry, cucumber, pumpkin and watermelon bees collected pollen almost exclusively from weeds and wildflowers during our sampling. Thus more attention must be paid to how honey bees are exposed to pesticides outside of the field in which they are placed. We detected 35 different pesticides in the sampled pollen, and found high fungicide loads. The insecticides esfenvalerate and phosmet were at a concentration higher than their median lethal dose in at least one pollen sample. While fungicides are typically seen as fairly safe for honey bees, we found an increased probability of Nosema infection in bees that consumed pollen with a higher fungicide load. Our results highlight a need for research on sub-lethal effects of fungicides and other chemicals that bees placed in an agricultural setting are exposed to.
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PMID:Crop pollination exposes honey bees to pesticides which alters their susceptibility to the gut pathogen Nosema ceranae. 2389 12

Studies of newly emerged Apis mellifera worker bees have demonstrated that their guts are colonized by a consistent core microbiota within several days of eclosure. We conducted experiments aimed at illuminating the transmission routes and spatiotemporal colonization dynamics of this microbiota. Experimental groups of newly emerged workers were maintained in cup cages and exposed to different potential transmission sources. Colonization patterns were evaluated using quantitative real-time PCR (qPCR) to assess community sizes and using deep sequencing of 16S rRNA gene amplicons to assess community composition. In addition, we monitored the establishment of the ileum and rectum communities within workers sampled over time from natural hive conditions. The study verified that workers initially lack gut bacteria and gain large characteristic communities in the ileum and rectum within 4 to 6 days within hives. Typical communities, resembling those of workers within hives, were established in the presence of nurse workers or nurse worker fecal material, and atypical communities of noncore or highly skewed compositions were established when workers were exposed only to oral trophallaxis or hive components (comb, honey, bee bread). The core species of Gram-negative bacteria, Snodgrassella alvi, Gilliamella apicola, and Frischella perrara, were dependent on the presence of nurses or hindgut material, whereas some Gram-positive species were more often transferred through exposure to hive components. These results indicate aspects of the colony life cycle and behavior that are key to the propagation of the characteristic honey bee gut microbiota.
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PMID:Routes of Acquisition of the Gut Microbiota of the Honey Bee Apis mellifera. 2523

Honey bees (Apis mellifera L.) are bioindicators of environmental pollution levels. During their wide-ranging foraging activity, these hymenopterans are exposed to pollutants, thus becoming a useful tool to trace the environmental contaminants as heavy metals, pesticides, radionuclides and volatile organic compounds. In the present work we demonstrate that bees can also be used as active samplers of airborne particulate matter. Worker bees were collected from hives located in a polluted postmining area in South West Sardinia (Italy) that is also exposed to dust emissions from industrial plants. The area is included in an official list of sites of national interest for environmental remediation, and has been characterized for the effects of pollutants on the health of the resident population. The head, wings, hind legs and alimentary canal of the bees were investigated with Scanning Electron Microscopy coupled with X-ray spectroscopy (SEM-EDX). The analyses pointed to specific morphological and chemical features of the particulate, and resulted into the identification of three categories of particles: industry-, postmining-, and soil-derived. With the exception of the gut, all the analyzed body districts displayed inorganic particles, mostly concentrated in specific areas of the body (i.e. along the costal margin of the fore wings, the medial plane of the head, and the inner surface of the hind legs). The role of both past mining activities and the industrial activity close to the study area as sources of the particulate matter is also discussed. We conclude that honey bees are able to collect samples of the main airborne particles emitted from different sources, therefore could be an ideal tool for monitoring such a kind of pollutants.
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PMID:Honey Bees (Apis mellifera, L.) as Active Samplers of Airborne Particulate Matter. 2614 82

Food allergy is defined as an IgE-mediated hypersensitivity response to ingested food with allergic symptoms ranging from urticaria to life-threatening anaphylaxis. Food allergy is thought to develop because of (1) failed induction of tolerance upon initial exposure to food antigen or (2) breakdown of established tolerance to food antigen. We review current understanding of the pathogenesis, epidemiology, and natural history of food allergy, including the unconventional IgE-mediated food allergy to mammalian meat known as alpha-gal food allergy. We highlight emerging data on food allergy treatment and prevention, emphasizing the growing appeal of manipulating the gut microenvironment using probiotics and helminth products to blunt systemic allergic responses to food.
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PMID:Food Allergy: Our Evolving Understanding of Its Pathogenesis, Prevention, and Treatment. 2704 4

Background. The honey bee (Apis mellifera) is the most important pollinator in agriculture worldwide. However, the number of honey bees has fallen significantly since 2006, becoming a huge ecological problem nowadays. The principal cause is CCD, or Colony Collapse Disorder, characterized by the seemingly spontaneous abandonment of hives by their workers. One of the characteristics of CCD in honey bees is the alteration of the bacterial communities in their gastrointestinal tract, mainly due to the decrease of Firmicutes populations, such as the Lactobacilli. At this time, the causes of these alterations remain unknown. We recently isolated a strain of Lactobacillus kunkeei (L. kunkeei strain MP2) from the gut of Chilean honey bees. L. kunkeei, is one of the most commonly isolated bacterium from the honey bee gut and is highly versatile in different ecological niches. In this study, we aimed to elucidate in detail, the L. kunkeei genetic background and perform a comparative genome analysis with other Lactobacillus species. Methods. L. kunkeei MP2 was originally isolated from the guts of Chilean A. mellifera individuals. Genome sequencing was done using Pacific Biosciences single-molecule real-time sequencing technology. De novo assembly was performed using Celera assembler. The genome was annotated using Prokka, and functional information was added using the EggNOG 3.1 database. In addition, genomic islands were predicted using IslandViewer, and pro-phage sequences using PHAST. Comparisons between L. kunkeei MP2 with other L. kunkeei, and Lactobacillus strains were done using Roary. Results. The complete genome of L. kunkeei MP2 comprises one circular chromosome of 1,614,522 nt. with a GC content of 36,9%. Pangenome analysis with 16 L. kunkeei strains, identified 113 unique genes, most of them related to phage insertions. A large and unique region of L. kunkeei MP2 genome contains several genes that encode for phage structural protein and replication components. Comparative analysis of MP2 with other Lactobacillus species, identified several unique genes of L. kunkeei MP2 related with metabolism, biofilm generation, survival under stress conditions, and mobile genetic elements (MGEs). Discussion. The presence of multiple mobile genetic elements, including phage sequences, suggest a high degree of genetic variability in L. kunkeei. Its versatility and ability to survive in different ecological niches (bee guts, flowers, fruits among others) could be given by its genetic capacity to change and adapt to different environments. L. kunkeei could be a new source of Lactobacillus with beneficial properties. Indeed, L. kunkeei MP2 could play an important role in honey bee nutrition through the synthesis of components as isoprenoids.
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PMID:Genome sequencing and analysis of the first complete genome of Lactobacillus kunkeei strain MP2, an Apis mellifera gut isolate. 2711 87


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