Aerobiology of Vigo, North-Western Spain: atmospheric pollen spectrum and annual dynamics of the most important taxa, and their clinical importance for allergy

Vigo is a city located in the northwest of the Iberian Peninsula. Influenced by the Atlantic climate, it is surrounded by a Eurosiberian-type vegetation, modified by the introduction of forestry and ornamental species. Different ruderal vegetation types, resulting from human influence, grow in the area. The study of the pollen content of the air of Vigo started in 1989, with a Cour trap. Average results for the period 1989–1995 are presented in this paper, together with the lowest and highest values found. The representativeness of the mean values is analysed by calculating the coefficient of variation of the data series. Most pollen types in the atmosphere of Vigo are from tree species (54.2%); an important proportion comes from herb species (43.9%) and very few (1.8%) correspond to shrub species. A total of 73 different pollen types have been identified. The most abundant, listed in decreasing order of mean annual values for the period, are:Pinus (25.1%), Poaceae (21.1%), Urticaceae (14.6%),Quercus (8.5%),Castanea (3.7%),Betula (3.6%),Eucalyptus (3.4%),Plantago (3.2%),Alnus (2.1%), Cupressaceae (2.1%), Oleaceae (1.6%;Olea 1.3%),Platanus (1.3%),Rumex (1.3%), Chenopodiaceae/Amaranthaceae (1.0%), Ericaceae (0.8%), Asteraceae (0.6%;Artemisia 0.1% andTaraxacum type 0.2%) andMercurialis (0.5%). A pollen calendar showing the annual dynamics of all these pollen types is presented in this paper. A parallel study of the clinical importance of respiratory allergies in Vigo was also conducted. From a sample of 2750 patients, 87.2% suffered from rhinoconjunctivitis, 26.0% of these due to pollen, and 78.3% from asthma, 17.2% due to pollen. The pollen types responsible for these allergies, listed in decreasing order, are: Poaceae (78%),Parietaria (12%),Chenopodium (11%),Plantago (9%), Oak (4%),Artemisia (3%),Pinus (3%),Eucalyptus (3%),Olea (2%),Platanus (2%),Castanea (2%),Taraxacum (2%),Rumex (2%),Betula (1%),Cupressus (1%) andMercurialis (1%).     

Fertility and child spacing among the urban Poor in a Third World city: The case of Calcutta,India

Studies of fertility behavior in the Third World have relied heavily on two variables, income and education, to explain variations in fertility rates. If the socio-economic variables traditionally employed to account for variations in fertility rates are invariant, what other factors could influence fertility rates and child spacing? On the basis of data from 180 slum households in Calcutta, India, the paper indicates that in a situation where material and social conditions are comparable, cultural and demographic variables play a major role in influencing reproductive behavior. In this case study, caste and family type are shown to have a significant effect on the numbers of surviving children. As regards child spacing, the woman's age is of paramount importance.     

Allergenic pollen in the atmosphere of Rohtak city,Haryana (India): a pioneer study

An attempt has been made in the present study to assess the allergenicity of dominant pollen types recorded from the atmosphere of Rohtak city. Skin prick test was performed with the antigenic extracts of 22 pollen types on 150 local patients who visited Asthma Clinic, University of Health Sciences, Rohtak. Markedly positive skin reactions (2+ and above) varied from 4.6 to 20.6 % to various pollen antigens. Cenchrus ciliaria (20.6 %), Zea mays (20 %) and Pennisetum typhoides (19.3 %) were the pollen allergens exhibiting maximum sensitivity. Antigenic extract of Cassia occidentalis, Cynodon dactylon and Ricinus communis showed marked skin reactivity in 18.6 % of patients. Prosopis juliflora, Chenopodium murale, Amaranthus spinosus, Cassia fistula and Cassia siamea showed 2+ and above reactions in 16.6, 15.3, 14.6 and 14.0 % of the local patients, respectively. Least reactivity (4.6 %) was shown to the antigenic extract of Cyperus rotundus. Out of 52 sera screened for the presence of specific IgE antibodies against different antigenic extracts, only 5.5 % showed >60 % binding. About 30 % and above binding was shown to the antigenic extracts of Z. mays, A. spinosus, R. communis and Xanthium strumarium. The concordance between positive skin reaction and serum-specific IgE antibodies ranged from 15 to 69 %.     

陕西中部黄土高原地区空气花粉组成及其与气候因子的关系——以洛川县下黑木沟村为例

空气花粉研究是现代孢粉学、植被变迁与预测的重要内容之一.陕西省黄土高原地区洛川县2007-2009连续2a的空气花粉分析表明:空气花粉组成与区域植被分布特征和植物花期一致.与2007—2008年相比,2008-2009年的花粉总通量及蒿属花粉通量明显增加,但木本植物花粉通量降低,这主要与2008-2009年降水明显偏少密切相关.2007-2008年降雨量高于500 mm,花粉组合中乔木花粉百分比高于30％,表现出森林植被特点;2008-2009年降雨量少于450 mm,花粉组合中草本花粉高于80％,乔木花粉低于10％,更多表现出草原植被特点.但从植被观测来看并没有明显的变化,表明花粉组合较植被对气候变化更为敏感.主要花粉类型与气候因子的相关分析表明:气候因子影响空气花粉的组成及数量.栎属、松属、蔷薇科花粉数量主要受春季温度影响,温度越高花粉数量越多;其他季节花粉数量主要受相对湿度影响,湿度越低,花粉数量越大.榆属花粉数量主要与冬季温度有关,温度越高,花粉数量越高.杨属只受春季温度影响,春季温度越低,花粉数量越多.胡颓子科花粉含量主要受春季相对湿度、风速影响,相对湿度越低,风速越大,花粉数量越多.绝大多数草本花粉数量均主要受春、冬季相对湿度及风速影响,相对湿度越低,风速越大,花粉数量越高;此外,禾本科花粉数量还受春季温度影响,温度越高,花粉数量越多;菊科花粉数量在夏秋季节还受温度、湿度和风速的共同影响,温度越低,湿度越低,风速越大,花粉数量越多.这些结果表明,黄土高原中部地区的空气花粉特征能反映区域植被组成,且对气候变化非常敏感,对认识和预测当地气候变化与植被动态等具有重要意义.     

Organization of the cytoskeleton in pollen tubes ofPyrus communis: a study employing conventional and freeze-substitution electron microscopy,immunofluorescence, and rhodamine-phalloidin

Summary The structure and organization of the cytoskeleton in the vegetative cell of germinated pollen grains and pollen tubes ofPyrus communis was examined at the ultrastructural level via chemical fixation and freeze substitution, and at the light microscopic level with the aid of immunofluorescence of tubulin and rhodamine-phalloidin.Results indicate that cortical microtubules and microfilaments, together with the plasma membrane, form a structurally integrated cytoskeletal complex. Axially aligned microtubules are present in cortical and cytoplasmic regions of the pollen grain portion of the cell and the distal region of the pollen tube portion. Cytoplasmic bundles of microfilaments are found in association with elements of endoplasmic reticulum and vacuoles. Axially aligned microfilaments are also found in this region, associated with and independent of the microtubules. Microtubules are lacking in the subapical region where short, axially aligned microfilaments are found in the cell cortex. In the apical region, which also lacks microtubules, a 3-dimensional network of short microfilaments occurs. Microfilaments, but not microtubules, appear to be associated with the vegetative nucleus.     

Conflict between sexes in the water strider, Gerris lacustris: a test of two hypotheses for male guarding behavior

We studied the effect of operational sex ratio on female reluctanceand male persistence to mate as well as on the length of copulationand postcopulatory guarding in Gerris lacustris by adding fivesurplus males or females to the basin with a pair in tandem.In the control treatment, a pair alone was tested. Accordingto the copulatory guarding hypothesis (CGH), males should prolongmating and guard females in the presence of surplus males. Accordingto the convenience polyandry hypothesis (CPH), females shouldshow lower levels of resistance to prolonged mating in the presenceof surplus males because the mating male protects the femaleagainst harassment from other males. As expected on the basisof both the CGH and CPH, mating (copulation + guarding) averagedlonger in the male-biased treatment. The behavior of males andfemales during mating suggested that both hypotheses hold true:females showed less resistance to prolonged mating (as predictedfrom CPH), and male behavior suggested stronger efforts to stayon the female when surplus males were present (as predictedfrom CGH). Comparisons of the treatment with surplus femaleswith the results from the mating pair without surplus individualssuggested that the capabilities of water striders in tandemto assess the sex of nearby nonmating striders are limited.     

Effects of invertebrate predation on the seasonal succession of a zooplankton community: a two year study in Lake Aydat,France

Saline playa lakes represent major geomorphic and hydrologic components of internal drainage basins in the arid to semiarid interior of Australia. These lakes mark the outcrop areas of regional shallow groundwater; thus, they are effective hydro-chemical sinks for elemental concentration and authigenic formation of carbonate, evaporite, and silica/silicate minerals.Field observations and petrochemical characterization of playa sediments from drainage basins in Western and Central Australia indicate that localized discharge of groundwater, from shallow aquifers in calcrete deposits, plays a fundamental role in geochemical evolution of playa-lake marginal facies. The available data indicates also that although evaporative concentration and salt recycling are major controls on geochemistry of the playas, yet a simple evaporative concentration model does not provide a complete explanation for brine evolution and particularly the geochemical process-product relationships observed in the individual playa lakes. The distribution of the chemical facies in the playas, in relation to geomorphic setting of the internal drainage basins, reflects a significant impact of variation in groundwater discharge pattern on the geochemical evolution of the playa lakes. Accordingly, the development of chemical facies in individual playas have progressed through repeated episodes of evaporative concentration, groundwater-level fluctuations and ion-exchange processes.     

Structural preference for changes in the direction of the Ca2+-induced transition: a study of the regulatory domain of skeletal troponin-C

The determinants for specificity in the Ca(2+)-dependent response of the regulatory N-terminal domain of skeletal troponin-C are a combination of intrinsic and induced properties. We characterized computationally the intrinsic propensity of this domain for structural changes similar to those observed experimentally in the Ca(2+)-induced transition. The preference for such changes was assessed by comparing the structural effect of the harmonic and quasiharmonic vibrations specific for each Ca(2+) occupancy with crystallographic data. Results show that only the Ca(2+)-saturated form of the protein features a slow vibrational motion preparatory for the transition. From the characteristics of this mode, we identified a molecular mechanism for transition, by which residues 42-51 of helix B and of the adjacent linker move toward helices (A, D), and bind to the surface used by the protein to interact with troponin-I. By obstructing the access of the target to hydrophobic residues important in the formation of the complex, helix B and the adjacent linker act as an autoinhibitory structural element. Specific properties of the methionines at the interaction surface were found to favor the binding of the autoinhibitory region. Located over hydrophobic residues critical for binding, the methionines are easily displaceable to increase the accessibility of these residues to molecular encounter.     

Angiostrongylus cantonensis: experimental study on the susceptibility of apple snails, Pomacea canaliculata compared to Pila polita

Six groups (15 snails/group) of Pomacea canaliculata and Pila polita were infected orally with 0 (control), 200, 400, 800, 1600 and 3200 first-stage Angiostrongylus cantonensis larvae (L1). The respective mean+/-SD third stage larvae (L3) worm recovery 1-month post-infection (p.i.) for P. canaliculata was 0, 1.4+/-5.42 (0.7%), 0.13+/-0.35 (0.03%), 0.07+/-0.26 (0.009%), 0.07+/-0.26 (0.004%), 0, and for P. polita 0, 64.33+/-21.38 (32.25%), 115.36+/-36.82 (28.93%), 265.33+/-90.01 (33.27%), 471.33+/-92.98 (29.60%) and 849.00+/-243.23 (26.61%). The susceptibility of A. cantonensis in P. polita was dose-dependent (p<0.001). In the three groups (nine snails/group) of P. polita given 500 L1, we studied the distribution of L3 in the internal organs (i.e., foot, head+esophagus, kidney, albumin gland, mantle, intestine, digestive gland) and found the highest density after 1, 2 and 3 months p.i. in the mantle at 29.37%, 31.09% and 37.45%. The infection rate in P. canaliculata was too low to study distribution rates.