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PubMed1984

[C]Sucrose Uptake and Labeling of Starch in Developing Grains of Normal and segl Barley.

Previous work showed that the segl mutant of barley (Hordeum vulgare cv Betzes) did not differ from normal Betzes in plant growth, photosynthesis, or fertility, but it produced only shrunken seeds regardless of pollen source. To determine whether defects in sucrose uptake or starch synthesis resulted in the shrunken condition, developing grains of Betzes and segl were cultured in [(14)C]sucrose solutions after slicing transversely to expose the endosperm cavity and free space. In both young grains (before genotypes differed in dry weight) and older grains (17 days after anthesis, when segl grains were smaller than Betzes), sucrose uptake and starch synthesis were similar in both genotypes on a dry weight basis. To determine if sucrose was hydrolyzed during uptake, spikes of Betzes and segl were allowed to take up [fructose-U-(14)C]sucrose 14 days after anthesis and the radioactivity of endosperm sugars was examined during 3 hours of incubation. Whereas less total radioactivity entered the endosperm and the endosperm cavity (free space) of segl, in both genotypes over 96% of the label of endosperm sugars was in sucrose, and there was no apparent initial or progressive randomization of label among hexose moieties of sucrose as compared to the free space sampled after 1 hour of incubation. We conclude that segl endosperms are capable of normal sucrose uptake and starch synthesis and that hydrolysis of sucrose is not required for uptake in either genotype. Evidence suggests abnormal development of grain tissue of maternal origin during growth of segl grains.

Journal Article↗
PubMed1994

Confocal image analysis of spatial variations in immunocytochemically identified calmodulin during pollen hydration, germination and pollen tube tip growth in Nicotiana tabacum L.

Using monoclonal anti-calmodulin antibodies in conjunction with confocal scanning laser microscopy we have analysed the spatial variations in the distribution pattern of calmodulin (CaM) during the sequential events of pollen hydration, germination and tube growth in Nicotiana tabacum. These immunocytochemical observations have been complemented by immunochemical studies wherein the anti-calmodulin antibody raised against pea CaM recognises a polypeptide of c. 18 kDa in the pollen extracts. Digitisation of confocally acquired optical sections of immunofluorescence images reveals that in hydrated pollen a high level of CaM is consistently present in the region of the germinal apertures. Subsequently, with the onset of germination a high CaM concentration was found associated with the plasma membrane of the germination bubble and in the cytoplasm in its vicinity, while in the vegetative cytoplasm a weak diffuse and intense punctate signal was registered. CaM immunostain was also detected in association with the plasma membrane of the tube tips in both short and long pollen tubes. Furthermore, the cytosol of the tubes invariably manifested an apically focused CaM gradient. We were, however, unable to detect any vacuolar association of CaM in the older regions of the pollen tubes. Although punctate immunostain was obvious across the pollen tube numerous punctate structures were invariably present in the extreme tip. The possible implications of these findings in development of cell polarity, polarised growth, maintenance of calcium homeostasis and CaM interactions with other mechanochemical motor proteins in effecting propulsion of organelles during pollen hydration, germination and pollen tube growth are discussed.

Blotting, Western↗
PubMed2006

Mendelian segregation for two-factor apomixis in Erigeron annuus (Asteraceae).

The inheritance of asexual seed development (apomixis) in Erigeron annuus (Asteraceae) was evaluated in a triploid (2n=3x=27) population resulting from a cross between an apomictic tetraploid (2n=4x=36) pollen parent and a sexual diploid (2n=2x=18) seed parent. Diplospory (unreduced female gametophyte formation) and autonomous development (embryo and endosperm together) segregated independently in the population yielding four distinct phenotype classes: (1) apomictic plants combining diplospory and autonomous development, (2) diplosporous plants lacking autonomous development, (3) meiotic plants with autonomous (though abortive) development and (4) meiotic plants lacking autonomous development. Each class was represented by approximately one-quarter of the population (n=117), thus corresponding to a two-factor genetic model with no linkage (chi(2)=2.59, P=0.11). Observations demonstrate that autonomous embryo and endosperm development (jointly) may occur in either reduced or unreduced egg cells. The cosegregation of the traits is attributed to tight linkage or pleiotropy. The data are consistent with the hypothesis that autonomous development in E. annuus is regulated by a single fertilization factor, F, which initiates development of both the embryo and the endosperm in the absence of fertilization.

Crosses, Genetic↗
PubMed2003

Pollen-tube growth pattern and chalazogamy in Casuarina equisetifolia (Casuarinaceae).

For a better understanding of pollen-tube guidance in relation to pollen-pistil interaction, we investigated the mode of pollen-tube growth in pistils of Casuarina equisetifolia, a monoecious, wind-pollinated species that undergoes chalazogamous fertilization. The pistil is bicarpellate, but only one of the two carpels develops with two ovules. One of these ovules develops more than four embryo sacs. Pistils usually require more than 1 month to reach maturity after pollen grains have been deposited on the stigmas. During that period, pollen-tube growth proceeds discontinuously in five distinct steps that lead up to fertilization: (1) from the stigma to the upper region of the style, (2) from the upper region of the style to a septum in the ovary, (3) from the septum to the surface of the funiculus, (4) from the funiculus to chalaza in the ovule, and (5) from the chalaza to an egg apparatus. Probably because of competitive interaction between male and female gametophytes (or ovules), one pollen tube is selected from among many during the first step (just before the second step), one ovule from the two during the second and third steps, and one embryo sac from more than four during the fourth and fifth steps. On the basis of our results, erroneous drawings and explanations reported in earlier publications on chalazogamy in Casuarinaceae should be brought into question.

Fertilization↗
PubMed1998

Identification of Cannabis pollens using an allergic patient's immunoglobulin E and purification and characterization of allergens in Cannabis pollens.

Cannabis pollen allergens were detected using the serum of an allergic patient. The allergens were then purified by sequential column chromatography (including DE52 cellulose and phenyl-Sepharose CL-4B) and preparative HPLC. The molecular weight of the allergens were determined as 10,050 and 13,706 by matrix-assisted laser desorption/ionization time of flight mass spectrometry. We utilised Western blotting and development of an enzyme-linked immunosorbent assay for the detection of Cannabis pollen allergens.

Allergens↗
PubMed1993

Development and Pollination Regulated Accumulation and Glycosylation of a Stylar Transmitting Tissue-Specific Proline-Rich Protein.

The extracellular matrix of stylar transmitting tissues of many angiosperms is enriched in secretory materials that are believed to be important for interactions with pollen tubes. We have previously characterized two related cDNAs (TTS-1 and TTS-2) for stylar transmitting tissue-specific proline-rich proteins (TTS proteins) from Nicotiana tabacum. We show here that TTS proteins are highly glycosylated proteins with apparent molecular masses ranging between 50 and 100 kD. Results from chemical and enzymatic deglycosylation suggest that TTS proteins have N-linked glycosyl groups, and the extensive glycosylation most probably has resulted from modifications at the proline residues. TTS proteins are localized to the intercellular regions between neighboring transmitting tissue cells, the space in which pollen tubes elongate as they migrate from the stigma toward the ovary. TTS mRNA and protein levels are regulated during pistil development and by pollination. The levels of TTS mRNAs and proteins increase with flower development and reach the maximal levels as flowers approach anthesis. These maximal levels are maintained in the styles for at least 3 to 4 days after pollination, during which time pollen tubes elongate and reach the ovary. Spatially, TTS mRNAs and proteins accumulate first in the stigmatic end of young styles, and their levels progressively increase toward the basal end as pistils mature. Pollination stimulates the levels of TTS mRNAs and proteins in hand-pollinated young styles, which normally accumulate relatively low levels of these TTS gene products. Pollination also qualitatively affects TTS mRNAs and proteins. In pollinated styles, TTS mRNAs are shorter than those in unpollinated styles and underglycosylated TTS protein species begin to accumulate. The elaborate regulatory mechanisms governing TTS mRNAs and proteins during development and by pollination strongly suggest that these proteins may play a functional role in the process of pollination.

Journal Article↗
PubMed2001

Development and reproductive capacity of Thrips hawaiiensis (Thysanoptera: Thripidae) and its potential as a major pest.

The effect of constant temperature on development, reproduction and population growth of Thrips hawaiiensis (Morgan) reared on a diet of pollen and honey solution was studied. Although hatchability and survival rates from egg hatch to adult were higher than 79% between 15 and 25 degrees C, they were lower than 55% at 10 and 30 degrees C. Developmental rates increased linearly as rearing temperature increased. It was estimated that 153.8 degree-days, above a lower threshold temperature of 10.4 degrees C, were required to complete development from egg to adult oviposition. According to these figures, between 11 and 18 generations of T. hawaiiensis could have developed annually under outdoor conditions in western Japan, between 1990 and 1999. Mean adult longevity decreased with increasing temperature, from a maximum of 102.7 days at 15 degrees C to a minimum of 27.8 days at 25 degrees C. The mean fecundity on pollen and honey solution was highest at 20 degrees C with 536.9 eggs per female. The highest intrinsic rate of natural increase (rm) 0.208 was observed at 25 degrees C.

Animals↗
PubMed2005

Profile and analysis of gene expression changes during early development in germinating spores of Ceratopteris richardii.

Analysis of an expressed sequence tag library with more than 5,000 sequences from spores of the fern Ceratopteris richardii reveals that more than 3,900 of them represent distinct genes, and almost 70% of these have significant similarity to Arabidopsis (Arabidopsis thaliana) genes. Eight genes are common between three very different dormant plant systems, Ceratopteris spores, Arabidopsis seeds, and Arabidopsis pollen. We evaluated the pattern of mRNA abundance over the first 48 h of spore development using a microarray of cDNAs representing 3,207 distinct genes of C. richardii and determined the relative levels of RNA abundance for 3,143 of these genes using a Bayesian method of statistical analysis. More than 900 of them (29%) show a significant change between any of the five time points analyzed, and these have been annotated based on their sequence similarity with the Arabidopsis proteome. Novel data arising from these analyses identify genes likely to be critical for the germination and subsequent early development of diverse cells and tissues emerging from dormancy.

Arabidopsis↗
PubMed2000

Comparison of outdoor allergenic particles and allergen levels.

INTRODUCTION: Spore and pollen counts have been used traditionally to determine aeroallergen exposure. Using a liquid based collector and enzyme immunoassays, we have developed methods for measuring airborne allergen concentrations. In this work we test the hypothesis that airborne allergen concentrations are directly related to spore and pollen counts. METHODS: Test samplers used included a high-volume cyclonic liquid impinger (SpinCon) and a standard spore trap (Burkard). Samples were collected on a weekly basis from May to October and were analyzed microscopically for spores and pollen grains. The liquid samples were analyzed by enzyme-linked immunoassay for the presence of allergens from Alternaria, Cladosporium, Aspergillus, oak, fescue, ragweed, and plantain. Specific Alternaria allergens Alt al and GP70 also were measured. RESULTS: Pollen counts for the SpinCon and Burkard collectors were similar, though spore counts were lower with the SpinCon. Detectable amounts of three of the seven allergenic species including fescue, ragweed, and Alternaria were present in air samples. Concentrations of pollens were seen in their respective seasons while fungal allergen levels varied throughout the period. Allergen levels generally agreed with particle counts, however peak allergen levels and peak particle counts for individual species did not correlate well. CONCLUSIONS: At flow rates of 236 L/min, the SpinCon is comparable to the Burkard for counting airborne pollen and spores. Samples collected by the SpinCon permit quantitative determination of allergen levels in outdoor air. The poor correlation between measured airborne allergen and related particles indicates the potential for significant allergen exposure in the absence of identifiable particles in air.

Air Pollutants↗
PubMed1981

Immunofluorescent localization of two water-soluble glycoproteins including the major allergen from the pollen of ryegrass, Lolium perenne.

Two major glycoproteins have been localized in sectioned grains of ryegrass pollen by direct and indirect immunofluorescence methods using Fluorescein isothiocyanate (FITC)-labelled IgG fractions of antisera. These glycoproteins are the major allergen, Group 1 allergen, and a principal antigen, Antigen A. Four methods of fixation were employed: freeze-drying, methanol, 2.5% glutaraldehyde and 4% paraformaldehyde for 1 h at 4 degrees C. The post-embedding staining technique of immunocytochemistry was used: anthers were embedded directly, or after dehydration, in JB-4 plastic resin and antibody reacted with sectioned pollen. The effects of these fixatives on the antibody combining sites of the antigens were quantified by a solid phase radioimmunoassay using [125I]protein A to measure antibody binding. In mature pollen, these antigens were located in the cytoplasm and in the complex wall. In developing grains early in the maturation period, specific fluorescence was concentrated at the periphery of the cytoplasm.

Allergens↗
PubMed1996

Arabidopsis profilins are functionally similar to yeast profilins: identification of a vascular bundle-specific profilin and a pollen-specific profilin.

Four members of the Arabidopsis profilin (pfn) multigene family have been cloned, sequenced and analyzed. By RNA gel blot analysis it has been shown that these four genes fall into two groups: one group (pfn1 and pfn2) is expressed in all organs of the plant and the other group (pfn3 and pfn4) in floral tissues only. Based on amino acid sequence alignment Arabidopsis profilins can be divided into the same two groups: PFN1 and PFN2 are 89% identical and PFN3 and PFN4 are 91% identical. Between these two groups they are 71-75% identical. The Arabidopsis profilins bind poly-L-proline and can complement both the Saccharomyces cerevisiae profilin deletion mutant and the Schizosaccharomyces pombe cdc3-124/profilin mutation, showing that the plant profilins are functionally similar to yeast profilins despite the low amino acid sequence homology. Analysis of pfn promoter-GUS fusion genes in transgenic Arabidopsis shows that pfn2 is specifically expressed in the vascular bundles of roots, hypocotyls, cotyledons, leaves, sepals, petals, stamen filaments and stalks of developing seeds, whereas expression of pfn4 is restricted to mature and germinating pollen grains.

Amino Acid Sequence↗
PubMed2026

Magnetic nanoparticle-mediated genetic transformation and gene editing system in loquat (Eriobotrya japonica).

Loquat (Eriobotrya japonica Lindl.) is a valuable subtropical fruit tree whose genetic improvement has been significantly constrained by the absence of an efficient genetic transformation system. Although Agrobacterium-mediated transformation is the most widely used method, it proves ineffective in loquat due to the species' recalcitrance to in vitro regeneration. Pollen-based transformation offers a promising alternative by bypassing the need for tissue culture. However, the pollen wall poses a major physical barrier to the uptake of exogenous DNA. In this study, we investigated magnetic nanoparticle (MNP)-mediated transformation as a novel strategy for loquat. We confirmed that loquat pollen contains tricolporate apertures with diameters ranging from 3.0 to 5.0 μm, which are structurally suitable for the entry of MNPs-DNA. Based on this finding, we developed and optimized a transformation protocol using polyethyleneimine-coated Fe3O4 nanoparticles to deliver genetic material into loquat pollen grains. Using this approach, we successfully generated stable transgenic loquat lines, including both overexpression and gene-edited mutants. To our knowledge, this is the first report of successful MNP-mediated pollen transformation in a woody plant species. This work establishes a robust and efficient genetic transformation platform for loquat, providing a valuable tool for functional genomics and molecular breeding, as well as a potentially applicable strategy for other recalcitrant woody plants.

Eriobotrya↗
PubMed2003

Occurrence of the allene oxide cyclase in different organs and tissues of Arabidopsis thaliana.

Occurrence of an essential enzyme in jasmonate (JA) biosynthesis, the allene oxide cyclase, (AOC) was analyzed in different developmental stages and various organs of Arabidopsis thaliana plants by immuno blot analysis and immunocytological approaches. Levels of AOC and of the two preceding enzymes in JA biosynthesis increased during seedling development accompanied by increased levels of JA and 12-oxophytodienoic acid levels after 4 and 8 weeks. Most tissues including all vascular bundles and that of flower buds contain AOC protein. Flowers shortly before opening, however, contain AOC protein preferentially in ovules, stigma cells and vascular bundles, whereas in anthers and pollen AOC could not be detected. The putative roles of AOC and JA in development are discussed.

Arabidopsis↗
PubMed1994

Female sterile tobacco plants are produced by stigma-specific cell ablation.

We identified a tobacco stigma-specific gene, designated STIG1. The STIG1 gene is developmentally regulated and expressed specifically in the stigmatic secretory zone. We used a chimeric STIG1-GUS gene to show that the stigma-specific STIG1 gene expression pattern is controlled primarily at the transcriptional level. We constructed a stigma-specific cytotoxic gene by fusing the STIG1 gene 5' regulatory region with the coding sequence of the Bacillus amyloliquefaciens barnase gene, to assess the role of the stigmatic secretory zone in the pollination process. Pistils of transgenic STIG1-barnase tobacco plants undergo normal development, but lack the stigmatic secretory zone and are female sterile. Pollen grains germinate on the ablated 'stigmatic' surface, but are unable to penetrate the transmitting tissue of the style. Application of stigmatic exudate from wild-type pistils to the ablated surface increases the efficiency of pollen tube germination and growth and restores the capacity of pollen tubes to penetrate the style. Our data demonstrate the importance of the stigmatic secretory zone in the pollination process and provide an approach to identify compounds produced by the stigma that are critical for successful pollination and fertilization to occur.

Amino Acid Sequence↗
PubMed1990

Nonpharmacologic means of preventing asthma.

Cessation of smoking in the home is one of the most important nonpharmacologic actions to be recommended. There is a highly significant increase in wheezing, coughing, and respiratory infections in children with smoking mothers, and this increase is directly proportional to the number of cigarettes smoked. Cord blood IgE levels are increased in babies whose mothers smoke during pregnancy. Other agents, such as sulpur dioxide and chemical pollutants from industrial processes may play a role in the development or exacerbation, of asthma symptoms and should be avoided. One of the most interesting areas in food allergy is whether breast feeding causes sensitization or induces tolerance in infants to foods ingested by the mother. There is an increase in asthma in second-generation immigrant populations who are exposed, from birth, to the Western style of living which increases their exposure to house dust mite. Several studies have shown that month of birth is important in the development of specific allergies, for example, in the incidence of birch pollen allergy in Scandinavia. The presence of a pet in the home at birth is associated with a greater incidence of allergy to that animal. Our study in asthmatic children has shown a strong association (p less than 0.001) between the presence of allergens in the air in their homes (sampled retrospectively in the month of birth) with a positive skin test to those allergens.(ABSTRACT TRUNCATED AT 250 WORDS)

Air Pollutants↗
PubMed2003

Induction of male sterile cabbage using a tapetum-specific promoter from Brassica campestris L. ssp. pekinensis.

The anther (tapetum)-specific gene BcA9 was isolated from Chinese cabbage, Brassica campestris L. ssp. pekinensis cv. Jangwon, using the Arabidopsis tapetum-specific A9 gene as a probe. The DNA and amino acid sequences of the coding region of the BcA9 gene showed high homology with A9 genes from Arabidopsis and B. napus. However, the DNA sequences of the 5' noncoding (promoter) region were different, except for the sequence from -281 to -89. To test the specific activity of this promoter, a plant expression vector, pGR011, was constructed by fusing the BcA9 promoter and the cytotoxic diphtheria toxin A-chain (DTx-A) gene. Several transgenic plants from cabbage, B. oleracea ssp. capitata, were obtained by way of Agrobacterium-mediated transformation. Southern blot analysis indicated that the tapetum-specific BcA9 promoter and DTx-A gene were successfully integrated into the genome of the transgenic cabbage. Under the control of the BcA9 promoter, expression of the cytotoxic DTx-A gene in the tapetal cells of the transgenic plants resulted in male sterile cabbages. Microscopic examination revealed that pollen grains in anthers of the male sterile cabbages had not developed normally, but the vegetative growth and phenotype showed no difference compared to wild-type plants.

Base Sequence↗
PubMed1999

Differential expression of a polygalacturonase gene family in Arabidopsis thaliana.

By systematic sequencing of a flower bud cDNA library from Arabidopsis thaliana, we have identified four cDNAs encoding polygalacturonase. The corresponding genes, together with seven other A. thaliana genes present in the databases, form a small gene family. Sequence comparisons of the deduced polypeptides within the gene family or with other plant polygalacturonases allow classification of the genes into different clades. Five polygalacturonases, including all those isolated from the flower buds, are closely related to the enzyme in pollen. Of the six remaining polygalacturonases, three are more closely related to the abscission-specific type of enzyme and two others to the fruit polygalacturonase. The last one is more distantly related to the others and might correspond to a new type of polygalacturonase. Expression of the different genes was analysed on Northern blots and by a PCR-based strategy. Results indicate that if, as expected, the cDNAs isolated from the flower bud library are strongly expressed in pollen, other genes are expressed at a low level in young developing tissues, such as in seedlings and roots, suggesting that they could be implicated in the cell wall modifications observed during cell elongation and/or expansion which occur in these tissues.

Arabidopsis↗
PubMed1998

Prevalence of atopy in students from Málaga, Spain.

BACKGROUND: Epidemiologic studies are necessary to determine the prevalence of allergic diseases. This varies widely depending on allergen preparations and patients studied. OBJECTIVE: To investigate the prevalence of atopic disease, skin test reactivity, total and specific IgE to common allergens, and other variables in a sample of students from Málaga, southern Spain. METHODS: Three hundred sixty-five students (age 17.9 +/- 1.18) were interviewed by an allergist. Skin prick tests were performed with Dermatophagoides pteronyssinus, Artemisia vulgaris, Plantago lanceolata, Chenopodium album, Olea europaea, Phleum pratense, Parietaria judaica, Cynodon dactylon, Alternaria tenuis, and cat dander. Total and specific IgE to D. pteronyssinus, Olea, and Parietaria were determined. RESULTS: Of all subjects studied, 19.9% suffered from rhinoconjunctivitis, 4.1% rhinoconjunctivitis plus asthma, 3.1% asthma alone, and 0.8% atopic dermatitis; 46.4% had a positive skin test to at least one allergen (28.2% to D. pteronyssinus, 20.4% to Olea, 13.8% to Phleum); and 43% had total IgE > 100 kU/L and 44.7% a family history of atopy. Allergic symptoms were strongly associated with skin test positivities and family allergic history. Patients with asthma or skin prick test positive had higher total IgE values than others (P < .01). There was a significant correlation between specific IgE values and wheal size in skin test. CONCLUSIONS: Our findings confirm the high prevalence of atopic diseases, and the close relationship of skin tests reactivity (or presence of specific IgE) to allergens with symptoms of asthma and rhinitis. The presence of a family history of allergic diseases influences the development of positive skin tests and atopic illness. Dermatophagoides pteronyssinus and pollen of Olea europaea were found to be the most common allergens.

Adolescent↗