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PubMed2003

Expressions of human p53 and c-myc gene homologues during caryopsis development in maize.

Tumor suppressor gene p53 and proto-oncogene c-myc have been proved to be highly conserved and participate in many PCD processes in animals. In maize, proteins and RNAs related to p53 and c-myc have already been reported and the sequences homologous to these two genes have also been localized onto maize chromosomes by FISH. In this study, using immunohistochemistry we investigated the expression patterns of maize genes homologous to human p53 and c-myc during caryopsis development stages in maize. In a giving stage after pollination, p53 homologue showed high levels in the antipodal cells, integument, immature endosperm, ovary wall, tracheary elements, and aleurone layer, while c-myc homologue showed low levels in these tissues, only before pollination showed high expression in polar nucleus. The results of TUNEL assay demonstrated that TUNEL positive signals were detected where p53 homologue showed high expression levels. In animal cells, p53 shows reverse function with that of c-myc, so does it in maize basically. These results demonstrated that p53 and c-myc homologues might play some important roles in PCD during caryopsis development in maize. There may be conserved mechanisms for PCD in animals and in high plants.

Apoptosis↗
PubMed2003

Urticaceae pollen concentration in the atmosphere of North Western Spain.

Plants of the Urticaceae family can develop into a pest on soils enriched with nitrogen. Urticaceae pollen is a biohazard because it elicits severe pollinosis. Pollen grains were sampled by using a Lanzoni seven-day-recording trap from February 1995-December 2000 in the atmosphere of the city of Ponferrada (Leon, North Western Spain). The Spearman test was used to analyse the statistical correlation between Urticaceae pollen and certain meteorological factors in different main pollination periods. Maximum values are reached in June and July, minimum levels are recorded in January and December. The parameters bearing the greatest positive influence on the occurrence of Urticaceae pollen grains are: temperature (maximum, minimum and mean), humidity (absolute, wet-bulb temperature, dew point and mixing ratio) and south western wind direction; negative parameters are: relative humidity, rainfall and period without wind. The highest correlation coefficients were obtained with temperature and wet-bulb. Absolute humidity and wet-bulb temperature yielded better correlation than relative humidity; hence, these two parameters must be included in this type of study. The use of one main pollination period or another in statistical analysis has an influence on the coefficient value. The behaviour of the pollen grains in the atmosphere during the year also influences the results.

Air Pollutants↗
PubMed2003

The diversification of Halenia (Gentianaceae): ecological opportunity versus key innovation.

The plant genus Halenia (Gentianaceae) consists of herbs growing in temperate and tropical alpine habitats and most species possess flowers in which nectar is produced in spurs. This probably helps reward only specialized long-tongued pollinators, and a narrow pollinator/flower relationship is thought to accelerate diversification rates (a key innovation). To test the pattern of diversification of Halenia against the unspurred sister group we reconstructed phylogenetic relationships among 22 species plus outgroups using nuclear ITS and chloroplast rpl16 intron sequence data. We show that Halenia originated in East Asia and migrated via North America into Central America. From there, it colonized South America three times independently, probably within the last million years. Significant changes in diversification rates were found during the evolution of Halenia using a sister group method, a likelihood method, and a diversity-through-time plot. In contrast to other studies, we could not observe a direct speciation rate effect of the evolution of nectar spurs in comparison with the unspurred sister group of Halenia. Rather, increases in diversification occurred following the colonization of Central and South America by spurred progenitor taxa. This later switch in diversification may have resulted from the availability of new geographical and ecological opportunities, or from the availability of more and different pollinators in these regions. Following the latter hypothesis, the nectar spurs were a preadaption and functioned as a key innovation only in this new biotic environment. After an initial rapid increase, a reduction in diversification rate was observed in Central America, probably illustrating density dependence of speciation rates. Finally, we found preliminary evidence for the key innovation hypothesis in geologically young spurred and unspurred lineages of Halenia in South America.

Adaptation, Biological↗
PubMed2003

[Structure and biodiversity of insect community on syconia fruits of Ficus racemosa in tropical rainforest of Xishuangbanna, China].

Ficus racemosa is a keystone plant in tropical rainforest of Xishuangbanna, Yunnan. The structure, dynamic and biodiversity of insect community on its syconia fruits were investigated in different plots located in Menglun nature reserve, ravine rainforest in the botanical garden, and secondary forest by Luosuo River. The results showed that the total number of collected insects were 184 264, belonging to 5 order, 19 families, 36 genera, and 51 species. Hymenoptera was the most dominant group, accounted for 37.3% of the total collected species. The pollinator of Ceratosolen fusciceps had huge individual quantities among Hymenoptera, and its successful pollination influenced the stability and development of F. racemosa population. In addition, the proportion of Lepidopter inspects was 31.4%, and the other 31.3% species belonged to Coleoptera, Homopter and Diptera. Through calculating diversity index, evenness index and richness of three plots, it showed that these three indexes were the highest in Menglun nature reserve, secondary in ravine rainforest, and low species diversity and richness in secondary forest by Luosuo River. The experimental results reported here showed that the insect species decreased, the individual number of common species increased, and special species reduced.

Animals↗
PubMed2004

The genetics of floral divergence and postzygotic barriers between outcrossing and selfing populations of Arenaria uniflora (Caryophyllaceae).

The genetic architecture of floral traits involved in the evolution of self-pollination provides a window into past processes of mating system divergence. In this study, we use two generations of crosses between highly selfing and predominantly outcrossing populations of Arenaria uniflora (Caryophyllaceae) to determine the minimum number, average dominance relationships, and pleiotropic effects of genetic factors involved in floral divergence. Comparison of the F1 and F2 phenotypic means with the expectations of a completely additive model of gene action revealed a primarily additive genetic basis for floral characters associated with mating system variation. The exception was flower life span, which showed partial dominance of the outcrosser phenology. In contrast to similarly divergent species, the substantial differences in flower size between these A. uniflora populations appear to involve relatively few genes of large effect (minimum number of effective factors = 2.2 +/- 2.8 SE). In addition, correlations among traits in the F2 generation indicate that pleiotropy may be an important feature of the genetic architecture of floral evolution in A. uniflora. The evolution of selfing via major modifiers of floral morphology is consistent with other evidence for ecological selection for preemptive self-pollination in A. uniflora. Analyses of the genetic basis of autonomous selfing were complicated by hybrid breakdown in both F1 and F2 generations. Only F1 hybrids showed reductions in female fertility, but about 30% of F1 and F2 hybrids exhibited partial or complete male sterility. Male sterile flowers were characterized by short stamens, reduced petals, and a lack of protandry, as well as indehiscent anthers. This morphological breakdown mimics environmental disruptions of floral development and may result from novel genic interactions in hybrids.

Analysis of Variance↗
PubMed2004

Environmental factors affecting the start of pollen season and concentrations of airborne Alnus pollen in two localities of Galicia (NW Spain).

Alnus pollen is an early component of the annual atmospheric aerosol of the north-west regions of Spain, which causes the first occurrence of allergic symptoms. Seasonal and intra-daily variation of Alnus pollination, and the influence that main meteorological parameters exert, was studied in this paper. Monitoring was carried out from 1993-2002, by using two Lanzoni VPPS 2000 volumetric samplers. Once the atmospheric behaviour of this pollen had been identified, the final objective was to elaborate predictive models to determine the onset of the Alnus pollen season and its concentrations during the pollination period in two localities of north-west Spain (Santiago and Ourense). Winter chilling required to overcome the bud-dormancy period was similar in both cities, with around 800 Chilling Hours (C.H.) and 5.5 degrees C threshold temperature. Calculation of heat requirement for bud growth was carried out with maximum temperature, with around 50 Growth Degree Days (G.D.D. degrees C) needed, with 6 degrees C threshold temperature. Data from 2002 were used in order to determine the real validity of the models. This year was not taken into account to establish the aforementioned models. The variation between the predicted start of the pollen season and the observed season was smallest in Ourense. Verifying the proposed models for predicting daily mean concentrations of Alnus pollen during the pollen season shows that the predicted curves fits the observed variations of daily mean concentrations.

Air Pollution↗
PubMed2004

[Comparison of habitats and seasonally differentiated distribution patterns of fig wasp populations associated with Ficus racemosa in Xishuangbanna].

The population distribution patterns of fig wasps associated with Ficus racemosa in Xishuangbanna were studied by using several indexes. The results indicated that the distribution patterns of 6 fig wasp species were all clump. The aggregative intensity of pollinating wasp (Ceratosolen fusciceps) population at primeval rain forest was nearly equal to that at seriously disturbed site, whereas they were both much higher than that at moderately disturbed site. In the meanwhile, the population aggregative intensity for the same wasp species was higher in rainy season than in dry-hot season, and the lowest was occurred in foggy-cool season. Non-pollinating wasp (Platyneura testacea, Platyneura mayri, Platyneura agraensis, Apocrypta westwoodi, Apocrypta sp.) population and each of their sex group were varied significantly in aggregative intensity, responding to the habitat change and seasonal alteration. The protection of original habitat should be focused on the protection of the mutualism of Ficus racemosa and fig wasps.

Algorithms↗
PubMed2005

Experimental studies of adaptation in Clarkia xantiana. II. Fitness variation across a subspecies border.

Because the range boundary is the locale beyond which a taxon fails to persist, it provides a unique opportunity for studying the limits on adaptive evolution. Adaptive constraints on range expansion are perplexing in view of widespread ecotypic differentiation by habitat and region within a species' range (regional adaptation) and rapid evolutionary response to novel environments. In this study of two parapatric subspecies, Clarkia xantiana ssp. xantiana and C. x. ssp. parviflora, we compared the fitness of population transplants within their native region, in a non-native region within the native range, and in the non-native range to assess whether range expansion might be limited by a greater intensity of selection on colonists of a new range versus a new region within the range. The combined range of the two subspecies spans a west-to-east gradient of declining precipitation in the Sierra Nevada of California, with ssp. xantiana in the west being replaced by ssp. parviflora in the east. Both subspecies had significantly higher fitness in the native range (range adaptation), whereas regional adaptation was weak and was found only in the predominantly outcrossing ssp. xantiana but was absent in the inbreeding ssp. parvifilora. Because selection intensity on transplants was much stronger in the non-native range relative to non-native regions, there is a larger adaptive barrier to range versus regional expansion. Three of five sequential fitness components accounted for regional and range adaptation, but only one of them, survivorship from germination to flowering, contributed to both. Flower number contributed to regional adaptation in ssp. xantiana and fruit set (number of fruits per flower) to range adaptation. Differential survivorship of the two taxa or regional populations of ssp. xantiana in non-native environments was attributable, in part, to biotic interactions, including competition, herbivory, and pollination. For example, low fruit set in ssp. xantiana in the east was likely due to the absence of its principal specialist bee pollinators in ssp. parviflora's range. Thus, convergence on self-fertilization may be necessary for ssp. xantiana to invade ssp. parviflora's range, but the evolution of outcrossing would not be required for ssp. parviflora to invade ssp. xantiana's range.

Adaptation, Biological↗
PubMed2006

The fitness effects of outcrossing in Calylophus serrulatus, a permanent translocation heterozygote.

Small and relatively isolated populations that occupy fragmented habitat are at risk of local extinction. However, fitness consequences of fragmentation related to mating distance, such as inbreeding depression following increased self- and near-neighbor mating, may not follow standard expectations in species with specialized genetic systems. We investigated the effect of mating distance on progeny fitness in Calylophus serrulatus, a primarily autogamous, permanent translocation heterozygote that is restricted to prairie fragments in the North American tallgrass prairie region. We pollinated flowers by hand in the field with pollen sampled at various distances from the maternal parent within and between three populations in southeastern Minnesota. We raised the progeny in a greenhouse and measured fitness-related characters. Because their genetic system prevents loss of heterozygosity throughout much of the genome, regardless of inbreeding, permanent translocation heterozygotes are not expected to exhibit inbreeding depression. Consistent with this expectation, in no case did progeny of self matings suffer significantly reduced mean fitness compared to progeny from crosses between plants. Crosses between plants in the two closely situated (2 km) populations yielded progeny with fitness intermediate to their parents, but crosses between each of those populations and the more distant (20 km) population yielded progeny with reduced fitness, suggesting outbreeding depression at this largest spatial scale. Similarly, fitness of self-pollinated progeny and progeny from "near" crosses (<2 m) within populations tended to be higher than "mid" (10-25 m) and "far" (>35 m) cross-progeny fitness. Under the current conditions of fragmentation, it seems likely that the distant matings that produce outbreeding depression are rare. It appears that mean fitness in this species is maintained in the context of severe fragmentation of its populations, largely because of its genetic system.

Crosses, Genetic↗
PubMed2006

[Dynamics of allozyme heterozygosity in Siberian dwarf pine Pinus pumila (Pall.) Regel populations of the Russian Far East: comparison of embryos and maternal plants].

Siberian dwarf pine, or Japanese stone pine, Pinus pumila (Pall.) Regel is widespread in eastern Siberia and the Russian Far East; the species is bird-dispersed and has a unique spreading or shrub living form. A mixed mating system (predominant outcrossing with self-pollination and matings of close relatives) leads to the formation of partly inbred progenies in P. pumila, as in the majority of other conifers. The question arises as to whether inbred individuals persist in the reproductive part of a population, which can have negative genetic consequences. The ADH, FDH, FEST, GDH, GOT, IDH, LAP, MNR, MDH, PEPCA, 6-PGD, PGI, PGM, SKDH, and SOD isozyme systems were analyzed to study the dynamics of heterozygosity in four P. pumila natural populations from the Pacific region, optimal for the species. Samples were collected in northern Koryakia, southern Kamchatka (two samples), and the Kunashir Island (Kurils). Wright's fixation index was used to estimate the level of inbreeding in embryos from dormant seeds resulting from free pollination and in maternal plants. A substantial level of inbreeding (F(IS) = 0.124-0.342) was observed in the embryo samples but not in three out of the four adult samples. The inbreeding level at the reproductive age was high only in the sample from Koryakia, which was explained by a relatively young age of plants in the population frequently affected by fires. A general increase in heterozygosity, characteristic of other conifers as well, was attributed to elimination of inbred progenies and by balancing selection for heterozygotes, which is a key factor maintaining allozyme polymorphism in populations.

Breeding↗
PubMed1991

Influence of seasonal variations on histamine release and other immunological parameters in pollinosis.

One hundred and fifty-six pollen-sensitive patients with sensitization to grass pollen only were chosen for this study; 65 patients were allergic to Dermatophagoides, while 45 were non-allergic subjects with no atopic history. The following tests were carried out on all patients: histamine release of total blood, basal histamine, total histamine, determination of total IgE and specific IgE (RAST) serum levels, serum hemagglutinating antibodies and skin tests. Seasonal increase of IgE was observed, with post-seasonal fall; 50% of the cases reached normal values. However, RAST as a semiquantitative method did not prove to be useful in the detection of variations in specific IgE levels. During pollination, an increase in titers in pollen-sensitive subjects was seen. This was attributed to a humoral immune response epiphenomenon which was independent of IgE. The histamine release test was significantly greater during pollination in pollen-sensitive subjects. The total of stored histamine increased during the months of allergenic exposure.

Animals↗
PubMed1991

Common airborne allergens and their clinical relevance in the Caracas valley.

In order to determine the sequential prevalence of pollen grains and fungi spores in the city of Caracas by the volumetric method of collection and its effect on the population at risk, the first multidisciplinary team of aerobiological research was structured through a protocol designed for five experimental stages namely: a) Determination of the climatological parameters: temperature, relative humidity, speed and wind direction, precipitation and atmospheric stability, through simultaneous records of meteorological status located in the metropolitan area of Caracas; b) Collection, identification, classification and determination of the local distribution of the most important pollen grains existing in the zone under study; c) Collection, identification and classification of the most important fungi spores in the area; d) Preparation of the first pollinic calendar of Caracas and e) Evaluation of possible implication of the environment and the response through the IgE antibody in the selected patients in the area under study. Our results show: 1) The climatic conditions existing during the sampling period coincide with the analysis of the last 20 years in the Valley of Caracas. 2) The Venezuelan Central University (UCV) station was elected as the most representative point for permanent sampling. 3) An ideal statistical method is obtained in order to determine the spatial arrangement in the sampler rod of a dense type of fungi spores typical of the area under study. 4) The first pollinic calendar of Caracas was structured and 5) A seasonal tendency of the IgE response is shown. These results suggest an evident interrelation between the suggested concept of polyseasonality and antigenic polysensitization, and between individual seasonality with a specific reactivity and, finally, between tropical mixed seasonality with the expression of combined respiratory pathologies in our environment.

Air↗
PubMed1991

Asteraceae aeropollen of the western United States Gulf Coast.

Volumetric air sampling was performed near Corpus Christi, Texas during 1988 and supplemented with data from 1987 and 1989. Frequencies of captured pollen grains of Parthenium hysterophorus, Ambrosia and allied genera, Helianthus, and other Asteracea were examined. Asteraceous aerospora in 1988 accounted for 22.1% of all pollen found, of which 83.4% were pollen of Ambrosia, 12.4% of Parthenium, and the remainder (4.1%) representative of other genera. Capture of native Ambrosia species and P. hysterophorus peaked in September and October in 1987 and 1988, but Parthenium pollen was also found year round with a smaller secondary peak during May, 1988 and 1989. In the winter a different Ambrosia pollen was captured which compared with A. hispida found in the Yucatan Peninsula and southern Florida at a time when no ragweed was flowering in the vicinity of Corpus Christi. Such a pollen capture probably represents long distance dispersal (ca. 600 miles, 965 km) on strong easterly to southerly prevailing winds. Pollen capture occurred most frequently during daylight hours when percent relative humidity was lower and near midnight when inversions occur. Comparison of pollen capture with meteorologic data demonstrated that photoperiodic responses probably account for the initiation and termination of Ambrosia flowering, and to some extent that of Parthenium, and not sharply lowered temperatures or frost for ending pollen release. Previous plant surveys have shown that P. hysterophorus is more common in the Corpus Christi area than species of Ambrosia, or any other Asteraceae, even though ragweed pollen capture proved 6.9 times greater. This disparity is most likely due to limited long distance dispersal of Parthenium pollen, less pollen produced per another, and a less developed mechanism of wind pollination (passive dispersal or amphiphilous). Since both Parthenium and Ambrosia are significant allergenic plants, correlations between airborne pollen of Parthenium and allergic potential suggest that a prolonged pollination season and perhaps increased allergenicity of unique Parthenium pollen proteins allow Parthenium to be a major allergen despite significantly less ambient pollen.

Air Pollution↗
PubMed1990

[Pollen allergy as an occupational disease in gardeners].

Pollinosis due to pollens of insect-pollinated ornamental plants is only acquired under special work specific conditions of exposure, first of all in manual pollination for seed production and in cultivation of new sorts. In a big plant nursery and in hobby gardeners we found 8 cases of pollinosis to cyclamens, 3 to begonia, 1 to gloriosa rothschildiana and 1 to several kinds of lilies. The confirmation as occupational disease and a successful prevention of relapses require a change of the work place. Hyposensitization may be tried. For a primary prevention recommendations are made.

Adult↗
PubMedDate not supplied

[Partial sterility of the pine tree in 1986 and 1987 in the vicinity of the Chernobyl nuclear power station].

Reproductive potency of Pinus silvestris was studied in 1986, and 1987 within the zone of Chernobyl accident by the estimates of the survival rate of seed-buds during the gametophyte and embryonal development. At the radiation level of 4 Gy a partial female pine sterility was manifested by the decreased gametophyte survival rate of seedbuds, pollinated in 1986, and by the diminished embryonal survival rate of seed-buds pollinated in 1985.

Accidents↗
PubMedDate not supplied

Occurrence and clinical profile of the sensitization to Chenopodium in the province of Córdoba (Spain).

The sensitization to pollen from the Amarantaceae and Chenopodiaceae families is responsible for some pollinoses according to various authors. Following an aeropalynological carried out by the Botany Division of our University, we investigated the sensitization to Chenopodium in our pollinic patients in order to establish their clinical patterns. We evaluated 14 variables in Chenopodium-sensitive (CHE +) and nonsensitive (CHE -) patients; the results were analysed by using a computerized statistical programme. Of the 1,000 records reviewed, 38% corresponded to pollinic patients, of whom 8.42% were sensitive to pollen from this family. We found no significant differences between the two groups in the parameters representative of atopic features (e.g. eosinophilia, IgE). However, marked differences were indeed found in the age of appearance of symptoms, frequency of clinical pictures, origin of the patients, duration of the symptoms and evolution upon immunotherapeutic treatment not involving this antigen. These findings endow the sensitization to Chenopodium with special features which should be taken into account in choosing a specific treatment.

Air↗
PubMedDate not supplied

Allergy to Artemisia vulgaris in the region of Warsaw.

From 446 pollinic patients, 398 of them (89%) were sensitive to the pollen of graminae and 187 (42%) to Artemisia Vulgaris. Sensitivity to the antigens of both increased the possibility of bronchial symptoms among pollinosis patients from 38% when only the allergy to graminae was present (up to 51%). Seventy eight percent of patients allergic exclusively to the pollen of grasses become symptomatic below the age of 20, whereas among 48 patients sensitive only to artemisia, in 71% the clinical symptoms appeared much later-after the age of 20. In half of these patients, the clinical symptoms were not only seasonal but also perennial. Almost 25% of these suffered from allergic skin reactions and 1/3 also from asthma. Eighty percent of Artemisia sensitive pollinic patients were also sensitive to the pollen of other plants from the family of compositae. The possible causes of the apparent increase of the prevalence of allergy to Artemisia Vulgaris are discussed.

Adolescent↗
PubMedDate not supplied

Parietaria judaica and dermo-respiratory allergy in Barcelona: a study of 250 cases.

The wide geographical distribution of parietaria in southern and western Europe is responsible for the high incidence of pollinic hypersensitivity. Our centre detected the existence of hypersensitivity to parietaria judaica in 250 patients (12.15%) out of a group of 2.057 patients. Exclusive consideration of the pollinic patients in this group 980/2,057 showed that the parietaria is the spore responsible for 25.5% of these patients. The most common symptomatology was rhinoconjunctivitis (41.2%) and the least frequent, the dermic picture (1.2%). The diagnostic methodology of these 250 patients included: anamnesis, rhinoscopy, rhinomanometry, skin tests, respiratory function, immunoglobulin levels (IgG, IgA, IgM, IgE), specific IgE and histamine release test. All patients were subjected to immunotherapy using parietaria judaica extracts. The overall evolution following immunotherapy was favourable in more than 80% of the patients, which confirms the suitability of the pareitaria judaica extract in the diagnosis and treatment of this pollinosis.

Adult↗