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PubMed2005

Expression and localization of calreticulin in tobacco anthers and pollen tubes.

The developmental expression pattern and localization of calreticulin were studied in Nicotiana tabacum L. anthers, pollen and pollen tubes. High transcript and protein levels were detected throughout anther development. Immunolocalization of calreticulin in the anthers showed particular dense label in tapetum and pollen at developmental stage 2, when the tapetum is highly active and the pollen tetrads are formed. Much lower transcript and protein levels were detected in dry and hydrated pollen and in pollen tubes. Immunofluorescence labeling of both chemically fixed and cryo-fixed and freeze-substituted pollen tubes showed the presence of calreticulin in Golgi apparatus and endoplasmic reticulum (ER). Calreticulin was seen throughout the stacks in the Golgi apparatus and in the areas with coated-Golgi vesicles but much less so in the ER. Calreticulin was not found in the secretory vesicles. A relatively intense label was occasionally seen adjacent to the wall of the tube. No significant label was observed in mitochondria, vacuoles, generative cells, cell wall or callose plugs. The present results are consistent with a role of calreticulin in Ca2+-dependent folding of secreted glycoproteins in tapetum, pollen and pollen tubes.

Calcium↗
PubMed2006

Effect of corn hybrids expressing the coleopteran-specific cry3Bb1 protein for corn rootworm control on aboveground insect predators.

Field and laboratory studies were conducted to determine the effect of transgenic Bacillus thuringiensis (Bt) corn, Zea mays L. (YieldGard Rootworm), expressing the Cry3Bb1 protein on aboveground nontarget insect predators (minute pirate bug, ladybird beetles, and carabids). Visual counts of adult and immature Orius insidiosus (Say), Coleomegilla maculata (DeGeer), Hippodamia convergens Gurin-Meneville, and Scymnus spp. occurring in Bt corn and its non-Bt isoline were made at Manhattan, KS, in 2002 and at Manhattan and Scandia, KS, in 2003. No significant differences were found between the Bt corn and non-Bt isoline plots in the abundance (number per plant) of O. insidiosus, C. maculata, H. convergens, and Scymnus spp. Field predation on Ostrinia nubilalis (Hübner) (Lepidoptera: Crambidae) egg masses was also observed during the silking stage of corn at Manhattan and Scandia in 2003. No significant differences were observed among treatments in predation rate for predators with chewing versus sucking mouthparts. Two laboratory studies determined the effect of Cry3Bb1 protein expressed in Bt corn pollen on C. maculata and carabids. The larvae of C. maculata were reared on Bt pollen, non-Bt pollen, or greenbugs, Schizaphis graminum (Rondani). The duration of larval and pupal stages, developmental time from egg hatch to adult emergence, percentage of survival, and elytra length were compared among treatments. There were no significant differences in developmental time of larvae fed pollen or greenbugs during their first two instars. However, significantly prolonged development of the third (1 d) and fourth instars (2 d) was observed for larvae fed greenbugs only. Total time for larval development was significantly longer for larvae that fed on greenbugs versus larvae fed on pollen. No significant differences were observed among treatments in the percentage of larvae that pupated or pupal stage duration. Larvae that fed on greenbugs had higher pupal and adult weights compared with pollen-fed larvae. However, pupal and adult weights did not vary between the Bt and non-Bt pollen treatments. No significant differences occurred in longevity and elytra length of beetles among all treatments. Two carabid species, Harpalus caliginosus F. and Harpalus pensylvanicus DeGeer, were reared on moistened dog food sprinkled with Bt or non-Bt corn pollen. No significant differences in mortality of H. caliginosus and H. pensylvanicus were detected among any of the treatments. There was no significant effect of Bt pollen on fecundity and egg viability of H. caliginosus. Our studies showed that YieldGard Rootworm had no effect on the selected coleopteran predators; therefore, this Bt corn hybrid could be used in an integrated pest management system.

Animals↗
PubMed1974

Physiological and Cytological Similarities between Disease Resistance and Cellular Incompatibility Responses.

Excised pea pods responded similarly to both the invasion of plant pathogenic fungi and the presence of bean tissue, bean pollen, and mouse tumor cells by synthesizing pisatin and by developing a characteristic yellow-green fluorescence. Both responses were dependent on RNA and protein synthesis. Conversely, the foreign pollen and incompatible fungi were sensitive to the pea pod tissue and were subject to abnormal development.The induction of pisatin and the yellow-green fluorescence development were mediated by multiple compounds of varying sizes released by fungi or mouse tumor cells. The incompatibility between a bean pathogen, Fusarium solani f. sp. phaseoli, and pea pod tissue was hypothesized to occur as a result of the cross contamination of such inducing compounds.

Journal Article↗
PubMed1991

[An enzyme-linked immunosorbent assay (ELISA) for the quantitation of sugi pollen and Dermatophagoides mite allergens and its application for standardization of allergen extracts].

A simple enzyme-linked immunosorbent assay (ELISA) has been developed for the quantitation of the major allergens of sugi pollen, Cry j I and of Dermatophagoides mites, Der I (Der p I/Der f I) and Der II (Der p II/Der f II) for use in the in vitro standardization of allergen extracts. Polystyrene microplates coated with a IgG fraction of rabbit antiserum were incubated first with allergen extracts and then with biotinylated antiserum IgG. The bound allergen-biotinylated antibody complex was detected with commercially available streptavidin-enzyme conjugate followed by the addition of colorimetric substrate. The assay was very sensitive (-0.2 ng/ml) and reproducible (CV% = 1.9-13.8%). The ELISA was compared with the radioimmunoassay previously described, and the results showed a very good correlation between the assays (r = 0.967-0.990). The allergen content in three sugi pollen and three house dust extracts measured by the ELISA also demonstrated a good agreement with the relative potency of these extracts as determined by the intradermal skin test. These results indicate that the ELISA could be useful in the standardization of allergen extracts.

Allergens↗
PubMed1999

Signaling in pollination.

The past year has seen considerable advances in our understanding of signaling in pollen tubes. Evidence suggesting that lipids are involved in pollen tube guidance has opened up new avenues. Major advances have been made in understanding the roles of Rho-like GTPases and protein kinases in regulating pollen tube growth. Light is being shed on how signals may be integrated. It is becoming clear that the role of Ca(2+) in pollen tube growth is perhaps more complex than originally anticipated.

Plant Cells↗
PubMed1999

A novel glycine-rich protein is associated with starch grain accumulation during anther development.

LIM14, originally identified as a lily gene associated with microsporogenesis, encodes a protein which has two distinct domains, one with glycine-serine repeats and the other with a hydrophobic signal peptide at the N-terminus. The putative LIM14 protein, however, is distinct from the glycine-rich cell wall proteins which have been described before. RNA analyses indicated that the LIM14 transcript is specifically detected in the anther from zygotene to young pollen stage. By using antibodies raised against recombinant LIM14 protein, we detected anther-specific 15 kDa protein. Immunofluorescence microscopy demonstrated that the LIM14 protein is associated with starch grains in the anther wall cells just prior to microspore mitosis and then accumulates at a higher level with the starch grains of immature pollen. We tagged LIM14 with the GUS and GFP reporter genes and introduced them into tobacco BY-2 cells. Analysis of the transformed cells revealed that the chimeric proteins are functional and specifically targeted to plastids. These results indicate that LIM14 is an anther-specific protein that may play a role in starch accumulation and amyloplast differentiation during anther development and pollen formation.

Amino Acid Sequence↗
PubMed2003

Exposure to high doses of birch pollen during pregnancy, and risk of sensitization and atopic disease in the child.

BACKGROUND: The role of maternal allergen exposure during pregnancy in sensitization and development of atopic disease in the child remains controversial. In the spring of 1993, extremely high levels of birch pollen were recorded in Stockholm, Sweden. In 1994, the corresponding pollen levels were low. The aim of this study was to assess the influence of exposure during pregnancy to high/low doses of birch pollen on the risk of sensitization and development of atopic disease in children. In addition, a comparison was made with children exposed to birch pollen in early infancy. METHODS: Three hundred and eighty-seven children with atopic heredity, born in Stockholm in July-October 1993 or 1994 (mothers exposed during pregnancy), were investigated at age 4.5 years. The children were clinically examined and were skin prick tested (SPT) with inhalant and food allergens. IgE antibodies (RAST) against birch pollen and recombinant birch pollen allergen (rBet v 1) were analysed in serum. A comparison was made with a similar group of children exposed during the same incident, but in the first 3 months of life, in 1993. RESULTS: The children of mothers high-dose exposed during pregnancy in 1993 tended to be more sensitized (SPT > or = 3 mm) to birch pollen than the children with low-dose exposure during the corresponding period in 1994 (7.6 and 4.6%, respectively, OR: 1.7; 95% CI: 0.7-4.1). A similar but weak tendency was seen for positive RAST analyses (> or =0.35 kU/l) against birch pollen and rBet v 1. Children of mothers high-dose exposed during pregnancy were significantly less sensitized to birch pollen than the children high-dose exposed in early infancy (17.9%, OR: 0.4; 95% CI: 0.2-0.7). There was an overall trend towards a slightly increased prevalence of bronchial asthma, allergic rhinoconjunctivitis and atopic dermatitis in the group with mothers high-dose exposed during pregnancy, compared to those with low exposure. CONCLUSION: Exposure of the mother during pregnancy to high levels of birch pollen resulted in a tendency towards increased risk of sensitization to the same allergen and symptoms of atopic disease in children with atopic heredity. Furthermore, our data indicate that exposure of the mother during pregnancy to inhalant allergens is less likely to result in sensitization in the child than exposure of the child in early infancy.

Asthma↗
PubMed2000

Multiple S gene family members including natural antisense transcripts are differentially expressed during development of maize flowers.

Within the large Brassica S gene family, SLG (S locus glycoprotein) and SRK (S locus receptor kinase) participate to the control of pollen-stigma self-incompatibility. In the self-compatible species maize, S gene family members are predominantly expressed in vegetative organs but are also expressed to a lesser extent in the stigma (silk). To determine if the expression of any S gene family members correlates with female receptivity, we analyzed their expression in developing maize silks. We show that a large family of maize S transcripts is expressed in developing silks. Surprisingly, we isolated a cDNA complementary to a large portion of the antisense strand of the maize receptor kinase S domain. Rapid amplification of cDNA ends (RACE)-polymerase chain reaction, RNase protection, and Northern hybridization with single-stranded riboprobes confirmed that natural antisense S transcripts exist in leaves and seedling shoots and in all sexual tissues tested except mature pollen. These natural antisense S transcripts co-exist with several less abundant sense S transcripts. The accumulation of sense and antisense S transcripts is differentially regulated during pollen and silk development. Thus, these results support a role for S gene family members in sexual tissue development and/or compatible pollination and reveal a new level of complexity in the regulation and function of the S gene family in maize.

Amino Acid Sequence↗
PubMed2003

A component of maize pollen that stimulates larval mosquitoes (Diptera: Culicidae) to feed and increases toxicity of microbial larvicides.

To explain how larval Anopheles arabiensis Patton feed effectively in the turbid water in which they frequently develop, we determined whether an extractable component of maize, Zea mays L., pollen enhances feeding by these mosquitoes. Maturing maize produces a copious amount of wind-borne pollen that is nutritious enough and produced over a sufficient period to support the development of at least one generation of anopheline mosquitoes. Larval An. arabiensis readily ingest the contents of maize pollen or the intact pollen grains themselves. An aqueous extract of maize pollen markedly accelerates the rate at which larval An. arabiensis ingest inert particles and strongly enhances the effectiveness of Bti against larval An. arabiensis. We conclude that the ability of larval anopheline mosquitoes to feed on maize pollen in turbid water is enhanced by the release from these pollen grains of a water-soluble phagostimulatory component (or components), which may be used to increase ingestion of microbial entomotoxins.

Animals↗
PubMed2004

Japanese cedar-pollen-specific IL-5 production in infants with atopic dermatitis.

BACKGROUND: Although food allergens and house dust mites are thought to contribute to the development of atopic dermatitis (AD) in infants, the influence of pollens has not yet been well defined. OBJECTIVE: This study attempted to clarify the effect of Japanese cedar pollens (JCPs), which are scattered in Japan between February and April, on AD in infants. METHODS: In the first study, seasonal changes in the number of patients who first visited our institute due to AD were analyzed by reviewing medical records of 184 infants with AD. In the second study, peripheral blood mononuclear cells from 81 children (50 infants <1 year and 31 older children) with AD were stimulated with a standardized JCP allergen. The production of IL-5 was measured and its correlation with the severity of AD in infants was analyzed. RESULTS: The number of infants who first visited the institute due to AD peaked in spring. JCP-specific IL-5 production began to increase immediately after the first contact with JCPs in infants with AD. The production of IL-5 in infants with AD exposed to JCPs was significantly higher than in control subjects (p < 0.002) or in AD infants never exposed to JCPs (p < 0.02). There was a significant positive correlation between IL-5 production and the severity of AD in infants (p < 0.0001). CONCLUSION: These results suggest that JCPs play an important role in the aggravation of infantile AD in spring by inducing IL-5 production.

Adolescent↗
PubMed2005

Worker honey bee ovary development: seasonal variation and the influence of larval and adult nutrition.

We examined the effect of larval and adult nutrition on worker honey bee (Apis mellifera L.) ovary development. Workers were fed high or low-pollen diets as larvae, and high or low-protein diets as adults. Workers fed low-protein diets at both life stages had the lowest levels of ovary development, followed by those fed high-protein diets as larvae and low- quality diets as adults, and then those fed diets poor in protein as larvae but high as adults. Workers fed high-protein diets at both life stages had the highest levels of ovary development. The increases in ovary development due to improved dietary protein in the larval and adult life stages were additive. Adult diet also had an effect on body mass. The results demonstrate that both carry-over of larval reserves and nutrients acquired in the adult life stage are important to ovary development in worker honey bees. Carry-over from larval development, however, appears to be less important to adult fecundity than is adult nutrition. Seasonal trends in worker ovary development and mass were examined throughout the brood rearing season. Worker ovary development was lowest in spring, highest in mid-summer, and intermediate in fall.

Animals↗
PubMed1993

Annual variations in grass pollen seasons in London 1961-1990: trends and forecast models.

The record of daily average grass pollen concentrations monitored at St Mary's Hospital, Paddington, London, U.K. since 1961 is the longest duration pollen data set in Europe. Analysis of the results identifies the trends and characteristics of grass pollen seasons over three decades. During this time seasonal allergic rhinitis has increased significantly in Britain. The annual start dates, length of season and severity are examined in relation to the main meteorological variables of cumulated temperatures above 5.5 degrees C and precipitation measured at one site within London and two in the surrounding rural areas. Land-use changes are also considered. Significant decreases have taken place in both the duration and severity of the seasons, particularly between the 1960s and the early 1970s but also through the last 20 yr. This is largely a result of a decrease in pollen abundance in the region. The decline in pollen counts has slowed in recent years due to the increase in flowering grasses caused by the set-aside policy and by uncut verges. Grass pollen seasons have tended to start later over the last two decades, despite an increase in the cumulated temperature profiles during late winter and spring. Empirical models have been developed using multiple regressions to incorporate meteorological and pollen data for the last 20 yr in order to forecast the start dates, duration and severity of the grass pollen seasons. These models were applied successfully using the data for 1991 and 1992. Predictions of the main characteristics of the pollen seasons can be obtained relatively early in the year through the use of these models by employing the monthly weather forecasts in conjunction with long-term average weather profiles.

Air↗
PubMed2006

Changes of serum cytokines after the long term immunotherapy with Japanese hop pollen extracts.

Japanese hop (Hop J) pollen has been considered as one of the major causative pollen allergens in the autumn season. We developed a new Hop J immunotherapy extract in collaboration with Allergopharma (Reinbeck, Germany) and investigated immunologic mechanisms during 3 yr immunotherapy. Twenty patients (13 asthma with rhinitis and 7 hay fever) were enrolled from Ajou University Hospital. Sera were collected before, 1 yr, and 3 yr after the immunotherapy. Changes of serum specific IgE, IgG1, and IgG4 levels to Hop J pollen extracts and serum IL-10, IL-12, TGF-beta1 and soluble CD23 levels were monitored by ELISA. Skin reactivity and airway hyper-responsiveness to methacholine were improved during the study period. Specific IgG1 increased at 1 yr then decreased again at 3 yr, and specific IgG4 levels increased progressively (p<0.05, respectively), whereas total and specific IgE levels showed variable responses with no statistical significance. IL-10, TGF-beta1 and soluble CD23 level began to decrease during first year and then further decreased during next two years with statistical significances. (p<0.05, respectively). In conclusion, these findings suggested the favorable effect of long term immunotherapy with Hop J pollen extracts can be explained by lowered IgE affinity and generation of specific IgG4, which may be mediated by IL-10 and TGF-beta1.

Bronchial Hyperreactivity↗
PubMed1997

[Perennial specific immunotherapy in pollen allergy].

Authors present perennial immunotherapy procedure that they developed with sublingal Perosall T 13 and Novo-Helisen Depot. The results of two-year observation of 70 patients undergoing above mentioned therapy.

Adolescent↗
PubMed2005

Pollen limitation or mate search need not induce an Allee effect.

When a process modelling the availability of gametes is included explicitly in population models a critical depensation or Allee effect usually results. Non-spatial models cannot describe clumping and so small populations must be assumed very diffuse. Consequently individuals in small populations experience low contact rates and so reproduction is limited. In Nature invasions into new territory are unlikely to be as diffuse as those described by non-spatial models. We develop pair approximations to a probabilistic cellular automata model with independent pollination and seed setting processes (equivalently mate search and reproduction processes). Each process can be either global (population-wide) or local (within a small neighbourhood) or a mixture of the two. When either process is global the resulting model recaptures the Allee effect found in non-spatial models. However, if both processes are at least partially local we obtain a model in which Allee effects can be avoided altogether if individuals are suitably strong pollinators and colonisers. The Allee effect disappears because small populations are dramatically more clumped when colonisation is local and less wasteful of pollen when pollination is local.

Algorithms↗
PubMed2026

Heat stress impact on rice reproductive processes: challenges and new approaches.

Heat stress represents one of the most severe abiotic constraints to rice (Oryza sativa L.) productivity and is expected to intensify under ongoing climate change, particularly affecting the reproductive phase and leading to substantial yield and grain quality losses. This review synthesizes current knowledge on the impacts of heat stress on rice reproduction, with a focus on both male and female reproductive structures and their interactions. Evidence from anatomical, physiological, transcriptomic, and metabolomic studies to describe how elevated temperatures disrupt key reproductive processes, including microsporogenesis, anther dehiscence, pollen viability, pollen-pistil interactions, fertilisation, and embryo sac development were integrated in this review. It further discusses the genotype-dependent differences in reproductive thermotolerance; and key genes, metabolites, and pathways associated with heat stress perception, signalling, and tolerance are highlighted. Finally, it is briefly discussed how recent advances in breeding strategies, functional genomics and genome-editing technologies, particularly CRISPR-based approaches, are providing new opportunities to enhance reproductive resilience to heat stress and how it is essential to close the existing molecular knowledge gaps in the development of heat-tolerant rice varieties capable of sustaining productivity in a warming climate.

Oryza sativa (L.)↗
PubMed1999

Follow-up after systemic adverse reactions of immunotherapy.

Out of 280 immunotherapy (IT)-treated patients in our allergy clinic, 37 (13%) developed systemic adverse reactions. Parietaria judaica (Pj) extract, a highly allergenic pollen in northern Israel, was part of the IT regimen in 46% of treated patients who developed systemic adverse reactions. Twenty-six (70%) of systemic adverse reactions occurred during the buildup phase, whereas 11 (30%) occurred in the maintenance phase of treatment. Mild systemic reactions developed in 15/37 (40%), moderate in 20/37 (54%), and severe in 2/37 (5%) of patients. In 22/37 (59% of our IT-treated patients, adverse reactions developed within 30 min after injection. Among these were the two patients with severe systemic reactions. In 19%, moderate adverse reactions appeared at 30-60 min; in 22%, mild to moderate reactions appeared after 1-2 h. Our study concludes that severe systemic reactions to IT usually appear within 30 min after injection. In Israel, IT with highly allergenic pollens such as Pj frequently causes systemic reactions, even during the maintenance phase of treatment. In such cases, the reduction of IT dosage should be more than 50% during the pollen season, and a waiting period of 1 h should also be considered.

Allergens↗
PubMed2001

Model for forecasting Olea europaea L. airborne pollen in South-West Andalusia, Spain.

Data on predicted average and maximum airborne pollen concentrations and the dates on which these maximum values are expected are of undoubted value to allergists and allergy sufferers, as well as to agronomists. This paper reports on the development of predictive models for calculating total annual pollen output, on the basis of pollen and weather data compiled over the last 19 years (1982-2000) for Córdoba (Spain). Models were tested in order to predict the 2000 pollen season; in addition, and in view of the heavy rainfall recorded in spring 2000, the 1982-1998 data set was used to test the model for 1999. The results of the multiple regression analysis show that the variables exerting the greatest influence on the pollen index were rainfall in March and temperatures over the months prior to the flowering period. For prediction of maximum values and dates on which these values might be expected, the start of the pollen season was used as an additional independent variable. Temperature proved the best variable for this prediction. Results improved when the 5-day moving average was taken into account. Testing of the predictive model for 1999 and 2000 yielded fairly similar results. In both cases, the difference between expected and observed pollen data was no greater than 10%. However, significant differences were recorded between forecast and expected maximum and minimum values, owing to the influence of rainfall during the flowering period.

Allergens↗