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International Archives of Allergy and... Feb 2003Grass pollens are one of the most important airborne allergen sources worldwide. About 20 species from five subfamilies are considered to be the most frequent causes of... (Review)
Review
Grass pollens are one of the most important airborne allergen sources worldwide. About 20 species from five subfamilies are considered to be the most frequent causes of grass pollen allergy, and the allergenic relationships among them closely follow their phylogenetic relationships. The allergic immune response to pollen of several grass species has been studied extensively over more than three decades. Eleven groups of allergens have been identified and described, in most cases from more than one species. The allergens range from 6 to 60 kD in apparent molecular weight and display a variety of physicochemical properties and structures. The most complete set of allergens has so far been isolated and cloned from Phleum pratense (timothy grass) pollen. Based on the prevalence of IgE antibody recognition among grass pollen-sensitized individuals, several allergens qualify as major, but members of two groups, groups 1 and 5, have been shown to dominate the immune response to grass pollen extract. Isoform variation has been detected in members of several of the allergen groups, which in some cases can be linked to observed genetic differences. N-linked glycosylation occurs in members of at least three groups. Carbohydrate- reactive IgE antibodies have been attributed to grass pollen sensitization and found to cross-react with glycan structures from other allergen sources, particularly vegetable foods. Another cause of extensive cross-reactivity are the group 12 allergens (profilins), which belong to a family of proteins highly conserved throughout the plant kingdom and present in all tissues. Members of eight allergen groups have been cloned and expressed as recombinant proteins capable of specific IgE binding. This development now allows diagnostic dissection of the immune response to grass pollen with potential benefits for specific immunotherapy.
Topics: Allergens; Amino Acid Sequence; Antigenic Variation; Cross Reactions; Humans; Hypersensitivity; Immunoglobulin E; Molecular Sequence Data; Poaceae; Pollen
PubMed: 12673063
DOI: 10.1159/000069013 -
Biochimica Et Biophysica Acta Jul 2013Pollen tubes grow rapidly by very fast rates and reach extended lengths to bring about fertilization during plant reproduction. The pollen tube grows exclusively at its... (Review)
Review
Pollen tubes grow rapidly by very fast rates and reach extended lengths to bring about fertilization during plant reproduction. The pollen tube grows exclusively at its tip. Fundamental for such local, tip-focused growth are the presence of internal gradients and transmembrane fluxes of ions. Consequently, vegetative pollen tube cells are an excellent single cell model system to investigate cell biological processes of vesicle transport, cytoskeleton reorganization and regulation of ion transport. The second messenger Ca(2+) has emerged as a central and crucial modulator that not only regulates but also integrates the coordination each of these processes. In this review we reflect on recent advances in our understanding of the mechanisms of Ca(2+) function in pollen tube growth, focusing on its role in basic cellular processes such as control of cell growth, vesicular transport and intracellular signaling by localized gradients of second messengers. In particular we discuss new insights into the identity and role of Ca(2+) conductive ion channels and present experimental addressable hypotheses about their regulation. This article is part of a Special Issue entitled:12th European Symposium on Calcium.
Topics: Calcium; Plants; Pollen; Pollen Tube; Pollination
PubMed: 23072967
DOI: 10.1016/j.bbamcr.2012.10.009 -
Microscopy Research and Technique Apr 2022Pollen micromorphology is not only used to check the functional and structural evolution in plants but also to solve the taxonomic problem related to the classification...
Pollen micromorphology is not only used to check the functional and structural evolution in plants but also to solve the taxonomic problem related to the classification of plants. Therefore, keeping in view the significance of pollen traits, selected taxa of the subfamily Caesalpiniaceae was collected from different geographical regions of Pakistan. The species were then analyzed under both light microscopy and scanning electron microscopy techniques to investigate the importance of micromorphological characters of pollen in the identification and classification of species. Great variation was recorded in equatorial shape, surface ornamentation, tectum, polar diameter, equatorial diameter, and exine thickness. However, little variation was observed in pollen type, polar shape, and fertility of pollen. The equatorial shape of five types was observed: prolate, prolate-spheroidal, spheroidal-subprolate, subspheroidal-prolate, and subspheroidal. Four types of surface ornamentation, psilate, granulate, clavate, and perforate, were recorded. Tectum of five types, intactate, reticulate regulate, medium reticulate, tactate, and striate, was observed. Sexine was thicker than nexine in all studied species. The largest polar diameter was observed in Caesalpinia pulcherrima 64.1 μm while the smallest in Parkinsonia aculeata 26.1 μm. The largest equatorial diameter was found in C. pulcherrima of 70.25 μm whereas the smallest in P. aculeata 27.57 μm. All the pollens analyzed were tricolporate. All studied species have a fertility ratio of more than 90%. A taxonomic key was developed to show the variation in pollen features and delimit species for the correct identification. In conclusion, the pollen traits were found useful to define species boundaries at various taxonomic ranks and will strengthen the taxonomy of this subfamily. Besides, this study also explored the palynological traits and their implication in the taxonomy of the subfamily Caesalpiniaceae.
Topics: Caesalpinia; Microscopy, Electron, Scanning; Pakistan; Pollen
PubMed: 34850481
DOI: 10.1002/jemt.24004 -
Journal of Proteome Research Dec 2007In higher plants, pollen grains represent the vestiges of a highly reduced male gametophyte generation. After germination, the pollen tube delivers the sperm cells by... (Comparative Study)
Comparative Study Review
In higher plants, pollen grains represent the vestiges of a highly reduced male gametophyte generation. After germination, the pollen tube delivers the sperm cells by tip-growing to the embryo sac for fertilization. Besides the intrinsic importance for sexual reproduction, pollen development and germination serve as an attractive system to address important questions related to cell division, cell differentiation, polar growth, cell-cell interaction, and cell fate. Recently, pollen functional specification has been well-studied using multidisciplinary approaches. Here, we review recent advances in proteomics of pollen development and germination.
Topics: Germination; Pollen; Pollen Tube; Protein Isoforms; Proteomics
PubMed: 17958392
DOI: 10.1021/pr070474y -
Computational and Mathematical Methods... 2022The pathogenesis of allergic rhinitis (AR) was affected by meteorological and environmental factors. This study investigated the association between clinical symptoms of...
BACKGROUND
The pathogenesis of allergic rhinitis (AR) was affected by meteorological and environmental factors. This study investigated the association between clinical symptoms of AR patients with pollen dispersal and meteorological conditions.
METHODS
The clinical features of 10,838 AR patients who were treated in the Department of Otorhinolaryngology, The First Hospital of China Medical University, Shenyang, from March 2021 to October 2021 were retrospectively analyzed. We collected pollen by a pollen collector, read and counted it under a microscope, identified the species of the pollen particles, and recorded meteorological data (average daily temperature, maximum and minimum temperature, average daily wind, average daily precipitation, average daily humidity, average pressure, air quality index, PM2.5, PM10, SO, NO, CO, and O), to analyze the correlation among meteorological conditions, pollen dispersal, and number of AR visits. Finally, pollen allergen-positive and symptoms were scored.
RESULTS
Among the AR visits, patients >41 years old accounted for the highest proportion (64.15%). 43.67% of the patients were complicated with bronchial asthma, and the disease incidence peaked in September. During the period of the study, a total of 27,512 pollen grains were collected, and 17 species were identified. The pollens of Compositae and Moraceae were the main allergenic sources leading to the increase in AR visits from August to September. The peak of pollen dispersal was in spring, summer, and autumn. The total amount of pollen was not only related to the average daily minimum temperature, average daily precipitation, and average daily humidity but also had a significant correlation with air quality index and air pollutants (PM2.5 and PM10, SO, NO, and CO). In addition, there was a significant correlation between the number of daily pollen allergen-positive patients and the pollen concentration of Compositae and Moraceae as well as air pollution components. The clinical symptoms of pollen allergen-positive patients were mainly nasal congestion, red/itchy eyes, and epiphora.
CONCLUSION
The peak seasons of pollen dispersal in Shenyang were in spring, summer, and autumn, and the allergenic pollens were mainly Compositae and Moraceae. In addition, AR was substantially correlated with pollen concentration and meteorological factors. This study may help provide early warning information and prevention for AR patients.
Topics: Adult; Air Pollutants; Allergens; Humans; Meteorological Concepts; Nitrogen Dioxide; Particulate Matter; Pollen; Retrospective Studies; Rhinitis, Allergic; Seasons
PubMed: 36203530
DOI: 10.1155/2022/4619693 -
Scientific Reports Jun 2021Pollen and molds are environmental allergens that are affected by climate change. As pollen and molds exhibit geographical variations, we sought to understand the impact...
Pollen and molds are environmental allergens that are affected by climate change. As pollen and molds exhibit geographical variations, we sought to understand the impact of climate change (temperature, carbon dioxide (CO), precipitation, smoke exposure) on common pollen and molds in the San Francisco Bay Area, one of the largest urban areas in the United States. When using time-series regression models between 2002 and 2019, the annual average number of weeks with pollen concentrations higher than zero increased over time. For tree pollens, the average increase in this duration was 0.47 weeks and 0.51 weeks for mold spores. Associations between mold, pollen and meteorological data (e.g., precipitation, temperature, atmospheric CO, and area covered by wildfire smoke) were analyzed using the autoregressive integrated moving average model. We found that peak concentrations of weed and tree pollens were positively associated with temperature (p < 0.05 at lag 0-1, 0-4, and 0-12 weeks) and precipitation (p < 0.05 at lag 0-4, 0-12, and 0-24 weeks) changes, respectively. We did not find clear associations between pollen concentrations and CO levels or wildfire smoke exposure. This study's findings suggest that spore and pollen activities are related to changes in observed climate change variables.
Topics: Allergens; Climate Change; Confidence Intervals; Fungi; Multivariate Analysis; Pollen; Seasons; Spores, Fungal
PubMed: 34140579
DOI: 10.1038/s41598-021-92178-z -
Microscopy Research and Technique Oct 2023A light and scanning electron microscopy technique was conducted to investigate the palynological features of 19 species belonging to 15 genera of the family Asteraceae....
A light and scanning electron microscopy technique was conducted to investigate the palynological features of 19 species belonging to 15 genera of the family Asteraceae. The species under investigation yielded pollen in a range of shapes, including spheroidal, prolate, and subprolate. Trizoncolporate, Tricolporate, and Tetracolporate are the three types of pollen apertures observed in examined species. Except for Gazania rigens, which has reticulate ornamentation under SEM, the exine pattern in all studied species is echinate. The majority of the species had isopolar polarity, whereas some members were apolar and heteropolar. The quantitative parameters that are polar to equatorial diameter, P/E ratio, length of colpi, width of colpi, length of the spine, width of spine, and exine thickness was measured by using light microscopy. The Coreopsis tinctoria had the lowest mean polar 19.75 μm to mean equatorial diameter 18.25 μm while the Silybum marianum had the highest polar 44.7 μm to equatorial 48.2 μm value. The value for colpi length/width was highest in Cirsium arvensis and lowest in C. tinctoria, measuring 9.7/13.2 μm and 2.7/4.7 μm, respectively. The spine length varied from 0.5 μm in Sonchus arvensis to 5.5 μm in Calendula officinalis. Verbesina encelioides had the highest exine thickness measurement (3.3 μm), whereas S. arvensis had the lowest (0.3 μm). The pollen surface of Tagetes erectus, has the highest number (65) whereas the lowest spines number (20) is found in S. arvensis. A taxonomic key based on pollen traits is provided for quick identification of the species. Significant implications for the systematics of the Asteraceae family can be drawn from the reported pollen's quantitative and qualitative data. RESEARCH HIGHLIGHTS: SEM and LM technique was used to study the palynological features of pollen grains. Quantitative and qualitative pollen features of 19 species of family Asteraceae are described. Morphological traits of pollen grains are important for the systematics of family Asteraceae.
Topics: Microscopy, Electron, Scanning; Pakistan; Pollen; Asteraceae
PubMed: 36876588
DOI: 10.1002/jemt.24308 -
Biochemical Society Transactions Apr 2010Many flowering plants are hermaphrodite, posing the problem of self-fertilization and the subsequent loss of the genetic fitness of the offspring. To prevent this, many... (Review)
Review
Many flowering plants are hermaphrodite, posing the problem of self-fertilization and the subsequent loss of the genetic fitness of the offspring. To prevent this, many plants have developed a genetically controlled mechanism called self-incompatibility (SI). When the male and female S-determinants match, self (incompatible) pollen is recognized and rejected before fertilization can occur. In poppy (Papaver rhoeas), the pistil S-determinant (PrsS) is a small secreted protein that interacts with incompatible pollen, initiating a Ca(2+)-dependent signalling network. SI triggers several downstream events, including depolymerization of the cytoskeleton, phosphorylation of two soluble inorganic pyrophosphatases and an MAPK (mitogen-activated protein kinase). This culminates in PCD (programmed cell death) involving several caspase-like activities. The recent discovery of the Papaver pollen S-determinant PrpS marks a significant step forward in the understanding of the Papaver SI system. PrpS encodes a ~20 kDa predicted transmembrane protein which has no homology with known proteins. It is specifically expressed in pollen, linked to the pistil S-determinant, and displays the high polymorphism expected of an S-locus determinant. The present review focuses on the discovery and characterization of PrpS which strongly support the hypothesis that Papaver SI is triggered by the interaction of PrsS and PrpS.
Topics: Cloning, Molecular; Flowers; Genetic Fitness; Inbreeding; Models, Biological; Ovule; Papaver; Plant Proteins; Pollen; Pollination
PubMed: 20298226
DOI: 10.1042/BST0380588 -
Science China. Life Sciences Jun 2022Timely programmed cell death (PCD) of the tapetum supplying nutrients to microspores is a prerequisite for normal pollen development. Here we identified a unique mutant...
Timely programmed cell death (PCD) of the tapetum supplying nutrients to microspores is a prerequisite for normal pollen development. Here we identified a unique mutant of rice (Oryza sativa L.), pollen sterility (post), which showed aborted pollens accompanied with extra-large husks. Due to failure of timely PCD of tapetal cells, post exhibited abnormal pollen wall patterning and defective pollen grains. By map-based cloning, we identified a causal gene, POST, encoding a novel protein which is ubiquitously localized in cells. RNA in situ hybridization showed that POST is highly detected in the tapetum and microspores at stages 8 and 9. Transcriptome analysis indicated that POST could function as an important regulator of the metabolic process involved in tapetal PCD. Compared with wild-type rice, post mutant has an increased cell number resulting from elevated expression of cell cycle associated genes in grain husks. Overexpression of POST inhibits grain size in wild type, while appropriate expression of POST in post mutant can recover the seed fertility but has little effect on the large grains, illustrating that fine-tuning of POST expression could be a potential strategy for rice yield improvement. The connection between cell division and cell death conferred by POST provides novel insights into the understanding of the tapetal PCD process.
Topics: Apoptosis; Cell Division; Flowers; Gene Expression Regulation, Plant; Infertility; Mutation; Oryza; Plant Proteins; Pollen
PubMed: 34767152
DOI: 10.1007/s11427-021-2011-2 -
Journal of the History of Biology Oct 2022This article examines how geologists, botanists, and ecologists used pollen as a proxy for past climates in the first half of the twentieth century. It focuses on a...
This article examines how geologists, botanists, and ecologists used pollen as a proxy for past climates in the first half of the twentieth century. It focuses on a particular challenge of measuring climate with pollen: pollen's mobility. As scientists came to learn, pollen from some vegetation is more mobile than others. Pollen's differential mobility challenged regional climatic conclusions because of the potential mixing of pollen from various locations. To minimize the effects of this problem, pollen analysts sought to decrease the noise produced by highly local or foreign pollen. Yet, many ground-truthing and calibration methods were not available to pollen analysts because of the temporal separation between the observer and the object of interest. Instead, pollen analysts had to make spatial meaning out of fossil pollen using empirical studies of modern pollen, inferences from macrofossils and successional history, and applying statistical theories to fossil pollen data. Many of these corrections factors relied on pollen analysts' knowledge of place, including elements like the location's topography, prevailing winds, and plant cover. These elements were a natural part of vegetation-pollen-climate interactions. Scientists needed to account for them to turn pollen into a proxy for climate. Pollen's movement was equally natural, but scientists decided to eliminate some pollen to augment the regional climate signal. These selective eliminations of place suggest that not all elements of place are equally important. Scientists had to omit some elements of place to make sense of the complexities of the natural world.
Topics: Pollen; Fossils; Plants
PubMed: 35637366
DOI: 10.1007/s10739-022-09677-6