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PubMed2005

Transgene dispersal through pollen.

Techniques used for the transfer of novel genes into host plant genomes have created new possibilities for crop improvement. The implementation of transgenic crop species into agriculture has introduced the possibility of transgene escape into the environment via pollen dispersal. Although the movement of pollen is a critical step in transgene escape, there is currently no system to monitor transgenic pollen movement under field conditions. The development of an effective in vivo monitoring system suitable for use under field conditions is needed for research and commercial purposes so potential risks can be quantified and evaluated. This chapter describes the development of a model system using green fluorescent protein (GFP) expression in pollen as a marker to monitor pollen distribution patterns. A pollen specific promoter was used to express the GFP gene in tobacco (Nicotiana tabacum L.). GFP was visualized in pollen and growing pollen tubes using fluorescent microscopy. Furthermore, the goal of this research was to compare the dynamics of pollen movement with that of gene flow by using another method of whole plant expression of GFP to estimate out-crossing frequencies by progeny analysis. Pollen movement and gene flow were quantified under field conditions. Pollen traps were collected and screened for presence of GFP-tagged pollen using fluorescence microscopy. Progeny from wild type plants were screened with a hand held ultraviolet light for detection of the GFP phenotype.

Gene Transfer Techniques↗
PubMed2001

Changes in neuronal acetylcholinesterase gene expression and division of labor in honey bee colonies.

Division of labor in honey bee colonies is highlighted by adult bees making a transition at 2-3 wk of age from working in the hive to foraging for nectar and pollen outside. This behavioral development involves acquisition of new tasks that may require advanced learning capabilities. Because acetylcholinesterase (AChE) hydrolyzes acetylcholine, a major neurotransmitter associated with learning in the insect brain, we searched for changes in AChE expression in the brain during bee behavioral development. Biochemical aspects of the AChE protein were similar in foragers and "nurse" bees that work in the hive tending brood. However, catalytic AChE activity was significantly lower in foragers. Cloning of bee AChE cDNA enabled mRNA analysis, which demonstrated that the forager-related decrease in AChE activity was associated with decreased AChE mRNA levels. This was particularly apparent in the mushroom bodies, a brain region known to be involved with olfactory and visual learning and memory. In addition, treatment with the AChE-inhibitor metrifonate improved performance in an olfactory-learning assay. These findings demonstrate long-term, naturally occurring developmental downregulation of AChE gene expression in the bee brain, and suggest that this genomic plasticity can contribute to facilitated learning capabilities in forager bees.

Acetylcholinesterase↗
PubMed1994

Confocal laser scanning microscopy of mitochondria within microspore tetrads of plants using rhodamine 123 as a fluorescent vital stain.

The present study demonstrates that rhodamine 123 penetrates the callose walls surrounding plant microspores before they are released from tetrads. The stain accumulates in active mitochondria due to the electrical potential across the mitochondrial membrane. Accumulation of dye does not occur in mitochondria of fixed cells and fades quickly when mitochondrial activity is inhibited by exposure to carbonyl cyanide m-chlorophenyl hydrazone. Rhodamine can be used as a viability test for microspores still within tetrads, thus making it possible to determine when during development genes leading to pollen sterility are expressed. Rhodamine 123 is excited by blue (550 nm) light and can thus be used with confocal laser scanning microscopy. Anthers of Nicotiana tabacum, Oenothera villaricae, Silene dioica and Lycopersicum esculentum were studied here.

Carbonyl Cyanide m-Chlorophenyl Hydrazone↗
PubMed2006

Risk assessment and community participation model for environmental asthma management in an elementary public school: a case study in Puerto Rico.

Asthma is a rapidly growing chronic disease in the general population of the world, mostly in children. Puerto Ricans have the highest prevalence of children with asthma among the Hispanic community in the US and its territories. Asthma and air quality are becoming a significant and potentially costly public health issue in Puerto Rico. The CDC has reported that in Puerto Rico, 320,350 adults have asthma and this number represents 11.5% of the island adult population. The north east municipality of Carolina, Puerto Rico, has the highest asthma prevalence in the 0 to 17 year old range (2001 data). In this study, we address the potential relationship between anthropogenic and naturally occurring environmental factors, and asthma prevalence in an urban elementary public school in Carolina in an effort to empower and engage communities to work on their environmental health issues. We integrated geographic information systems (GIS) data of anthropogenic activities near the school as well as the natural resources and geomorphology of the region. We found that as Carolina is close by to Caribbean National Forest (El Yunque), this together with the temperature and precipitation cycles in the zone creates the ideal environmental conditions for increased humidity and pollen, mold and fungi development through out the year. We also collected health and socio economic data to generate an asthma profile of the students, employees and parents from the school community, and through a survey we identified perceptions on environmental asthma triggers, and indoor air quality in the school and homes of the students and employees. Finally, we implemented a workshop on indoor air quality designed to engage the school community in managing asthma triggers and the school environment. Our results showed that nearly 30 % of its student's population has asthma, and from this group 58% are males and 42% are female students. Of all asthmatic children, only 43% receive treatment for the disease. The study also showed that most asthmatic children are between 7 and 9 year old, and live in households with an annual income below 10,000 dollars. It also showed that 25 % of the student's parents have the condition, and that 25% of the employees are also affected by this chronic condition. All these numbers are significantly higher than those reported by the CDC for Puerto Rico. The perception component had a response of 83% of school employees, and a 39% response from parents. It showed that people know asthma as a disease but many can't identify most environmental asthma triggers. Pre and post tests of the workshop protocol showed that before the activity only 21% of participants can identify asthma triggers. At the end of the workshop nearly 80% were able to identify and manage environmental asthma triggers. This work validates the fact that Puerto Rico continues to have a significant number of people with asthma, particularly children asthma, and that schools are an important settings to create community based action plans to manage environmental asthma triggers through outreach and training.

Asthma↗
PubMed2003

[Pterygium: allergic etiology?].

Pterygium is a wedge-shaped fibrovascular growth of conjunctiva that extends onto the cornea. The etiopathogenesis of pterygium is still not fully elucidated. Exposure to ultraviolet light is suggested as one of the most important factors contributing to pterygium development. However, other factors including allergens, harmful chemical substances, wind, dust and pollens also may contribute to its development. The aim of the study was to evaluate the influence of immune reactions on the pathogenesis of pterygium.

Antigens, CD↗
PubMed2001

SPATULA, a gene that controls development of carpel margin tissues in Arabidopsis, encodes a bHLH protein.

Studies involving mutants of the gene SPATULA indicate that it promotes the growth of carpel margins and of pollen tract tissues derived from them. We show that it encodes a new member of the basic-helix-loop-helix family of transcription factors. SPATULA is expressed in marginal and pollen tract tissues throughout their development confirming its role in regulating their growth. It is also expressed in many other tissues where it may act redundantly to control growth, including the peripheral zone of the shoot apical meristem, and specific tissues within leaves, petals, stamens and roots. Expression in the stomium, funiculus and valve dehiscence zone indicates an additional role in abscission. SPATULA expression does not require the function of the other carpel development genes CRABS CLAW and AGAMOUS, although its expression is repressed in first whorl organs by the A function gene APETALA2. Further, we have shown that disruptions to gynoecial pattern formation seen in ettin mutants can largely be attributed to ectopic SPATULA action. ETTIN's role seems to be to negatively regulate SPATULA expression in abaxial regions of the developing gynoecium. SPATULA is the first basic-helix-loop-helix gene in plants known to play a role in floral organogenesis.

AGAMOUS Protein, Arabidopsis↗
PubMedDate not supplied

The role of pollen in chalkbrood disease in Apis mellifera: transmission and predisposing conditions.

Chalkbrood in honeybees (Apis mellifera L. Himenoptera: Apidae) is a fungal disease caused by Ascosphaera apis (Maassen ex Claussen) Olive and Spiltoir. This disease requires the presence of fungal spores and a predisposing condition in the susceptible brood for the disease to develop. In this study we examined the role of pollen in the development of chalkbrood disease under two experimental conditions: (i) pollen combs were transferred from infected to uninfected beehives and (ii) colonies were deprived of adequate pollen supplies to feed the brood. The results of both treatments confirmed that pollen is an element that should be taken into account when controlling this honeybee disease.

Animals↗
PubMed2006

Over-expression of a flower-specific transcription factor gene AtMYB24 causes aberrant anther development.

In plants, MYB transcription factors play important roles in many developmental processes and various defense responses. AtMYB24, as a member of R2R3-MYB gene family in Arabidopsis, was found mainly expressed in flowers, especially in microspores and ovules using Northern blots and in situ hybridization. It was further found that the expression of AtMYB24 was tightly regulated during anther development. Over-expression of AtMYB24 in transgenic plants resulted in pleiotropic phenotypes, including dwarfism and flower development defects, in particular, producing abnormal pollen grains and non-dehiscence anthers. Further analysis showed that the anther development of the AtMYB24-ox lines was retarded starting from the anther developmental stages 10-11. At stages 12 and 13, the septum and stomium cells of anthers would not break, and fewer or no fibrous bands were found in the endothecium and connective cells in the AtMYB24-ox plants. Similar aberrant anther phenotype was also observed in the AtMYB24-GR-ox lines treated with dexamethasone (DEX). Quantitative real-time PCR showed expression of genes involved in phenylpropanoid biosynthetic pathway, such as CHS and DFR, and AtGTP2 were altered in AtMYB24-ox lines. These results suggest an important role of AtMYB24 in the normal development of anthers in Arabidopsis.

Amino Acid Sequence↗
PubMed1991

Relationship between IgG1 and IgG4 antibodies to foods and the development of IgE antibodies to inhalant allergens. II. Increased levels of IgG antibodies to foods in children who subsequently develop IgE antibodies to inhalant allergens.

In the present investigation we have tested the hypothesis that children with a high IgG antibody response to foods have an increased risk of developing IgE antibodies to inhalant allergens. Sera from 106 children with an increased risk of developing IgE-mediated allergy were analysed. During the follow-up, in 54 of these children IgE antibodies to inhalant allergens appeared. A positive/negative IgG1 and IgG4 anti-food score was determined as described previously: sera from age-clustered unselected children were tested for the levels of IgG1 and IgG4 antibodies to common foods. For each IgG RAST and each age group, the 75-percentile was chosen as cut-off value. Each antibody level was thus converted into a positive (higher than the 75-percentile of the age group) or negative value. The number of positive tests was used as the score. High-risk children with a high IgG1 anti-food score more often developed inhalant-specific IgE antibodies than high-risk children with low IgG1 titres: 50% of the children with a high IgG1 anti-food score developed IgE antibodies to grass pollen. Fifty per cent of the children with a high and 14% of the children with a low IgG1 anti-food score developed IgE antibodies to cat dander. For the prediction of the development of IgE anti-mite (house dust mite), the IgG4 anti-food scores appeared less useful than the IgG1 anti-food scores; 46% of the IgG4 high responders versus 22% of the IgG4 low responders acquired IgE anti-mite, whereas for IgG1 these percentages were 73 and 19, respectively.

Allergens↗
PubMed1993

Air pollution and pollen allergy.

Pollen allergy is the most typical form of allergic diseases. The increase in its frequency during recent years is most evident. The disease was rare when it was first described 150 years ago as summer hay fever. In 1876 Blackley wrote that the frequency of pollen allergy was increasing, especially in industrialized countries. Nowadays the prevalence of pollen allergy is well above 10%. Among the patients predominate the inhabitants of large cities, but not rural residents. Allergy develops as a result of multiple interactions between the human immune system and the environment. The current state of knowledge does not permit precision about the importance of genetic and environmental factors. It appears that although genetic control is very important, the environmental influences seem most important in determining the specific allergens to which a person will develop hypersensitivity. The adjuvant factors of the environment play an important role in the increasing problem of pollen allergy in large cities. Air pollution such as sulphur dioxide, ozone, nitrogen oxides, occupational dust, organic and inorganic suspended particulate matter, tobacco smoke, etc., can cause an increase in airway reactivity through mechanisms dependent on or independent of specific IgE antibodies. By irritating the airways and skin, pollen grain penetration into the human body can increase. Defective permeability of tissue surface can increase the risk of infection. Air pollution may also increase the development of pollen allergy through a direct influence on the pollen grains (on their enzymes, plant growth etc.). Lastly, the pollen grains may carry on their surfaces the various substances which are known as environmental allergens.(ABSTRACT TRUNCATED AT 250 WORDS)

Air Pollution↗
PubMed2003

Pollen count forecasting.

Pollen forecasting is becoming increasingly important to allergists as an adjunct to effective patient care. Forecasts allow patients to avoid exposure to high pollen levels and prompt them to take prophylactic medication and to plan outdoor activities for periods of low pollen levels. Investigators are making progress in developing effective models for daily and seasonal forecasts for important pollen allergens; however, current models are limited to specific geographic areas. Models for the onset of the season for spring tree pollen are based on the chilling and heat units that are required before flowering can occur. Models for pollen season severity are based on regression analysis of preseason meteorologic conditions, and models for daily forecasts are based on the normal pollen curve and responses to day-to-day meteorologic conditions. When winds are favorable, long-distance transport can introduce allergenic pollen types into a local area. The Mountain Cedar Pollen Forecasting model, which combines day-to-day release forecasts at source areas and dispersion forecasts to downwind areas, has been reasonablly successful over the past 4 years. All pollen forecasting models are dependent on accurate meteorologic forecasts, and pollen forecasting will become more accurate as meteorologic forecasts improve.

Forecasting↗
PubMed2005

Genome-wide identification and molecular characterization of Ole_e_I, Allerg_1 and Allerg_2 domain-containing pollen-allergen-like genes in Oryza sativa.

Pollen allergens play important roles in plant development in addition to their allergenic nature for human. More than 10 groups of pollen allergens have been reported. Among them, Pollen_Ole_e_I (Ole), Pollen_allerg_1 (Allerg1) and Pollen_allerg_2 (Allerg2) domain-containing proteins are the majority of allergens. We have identified 114 pollen-allergen-like genes in rice genome by bioinformatics using public databases. Among them, 45 genes encode Ole domain-containing proteins, 62 with Allerg1 and 7 with Allerg2. They are distributed on 11 of 12 rice chromosomes excluding chromosome 11. Comparison analysis of coding regions from both predicted genes and isolated full-length cDNAs showed that most of predicted genes were correct in the splicing of exons and introns, and only 7 exhibited wrong predictions. The fact suggested the applicability of the prediction programs to identify pollen-allergen genes. Phylogenetic analysis revealed the high diversity within OsOle genes and recent evolutionary event in OsAllerg1 genes, and suggested that some of OsOle genes were new members of the family. Expression analysis by RT-PCR showed that most of the genes were expressed in all tested tissues and only eight genes exhibited panicle-specific expression, suggesting that pollen-allergen genes play roles in not only productive but also vegetative development.

Allergens↗
PubMed2003

Efficacy of sublingual immunotherapy in grass pollen allergy.

Sublingual immunotherapy (SLIT) was developed to improve the safety of specific immunotherapy; however, its effectiveness is still subject to discussion although the balance sheet for SLIT is improving. In SLIT laboratory parameters and objective measures of allergen reactivity are nonuniform even in studies showing clinical effectiveness, thus subjective symptom scores remain the principal end points. For allergic rhinitis an expert panel collaborating with the WHO recently proposed that SLIT was a viable alternative for injectable immunotherapy (SIT) since a multitude of double-blind placebo-controlled studies had proved the effectiveness of SLIT. Unfortunately, there are only a small number of studies comparing effectiveness of SLIT directly with subcutaneous SIT. These studies demonstrated comparable effectiveness of both therapies. According to the data so far SLIT can be recommended for the therapy of allergic rhinitis in adults and children refusing injectable therapy. For the treatment of allergic asthma both positive and disappointing results have been published. Effectiveness in preventing the onset of allergic asthma in patients with allergic rhinitis has been demonstrated for SIT, while for SLIT this question cannot yet be answered.

Administration, Sublingual↗