The daily variations of airborne fungal spores in Mexico City

The daily and seasonal distribution of airborne fungal particles was recorded in a high altitude tropical zone. Sampling was carried out in the southern part of Mexico City. An Andersen air sampler was used over a period of six months. Ten minutes sampling for each set of plates was done at fixed schedule: 07:30, 14:00 and 19:00 hours. The sampler was placed 10 m above the ground. Daily variation was found to be associated with the season, weather and atmospheric stability. The highest value of mold counts (3195 CFU m⁻³) was recorded in the evening on October, a transitional month between the rainy and the dry seasons, the lowest (45 CFU m⁻³) at noon during the rainy season. Mold counts were significantly correlated with temperature, having negative signs both in the morning and at noon, and being positive in the evening. The abundance of only three genera was recorded.Cladosporium, was isolated more frequently, and its abundance at 14:00 h was of 38%;Alternaria represented 4.0%, at 14:00 h, andAspergillus 3.0% at 7:30 h. Fifteen species belonging to the latter genera were identified and most of them are considered as opportunistic molds of clinical significance.     

Meteorological effects on variation of airborne algae in Mexico

Sixteen species of algae were collected from 73.8 m³ of air. Eleven were obtained in Minatitlán and eleven in México City. The data show that similar diversity occurred between the two localities, in spite of the difference in altitude. This suggests that cosmopolitan airborne microorganisms might have been released from different sources. Three major algal divisions (Chlorophyta, Cyanophyta and Chrysophyta) formed the airborne algal group. Also, a large concentration of 2220 algae m^–3 was found near sea-level, while lower amounts were recorded at the high altitude of México City. The generaScenedesmus, Chlorella andChlorococcum dominated. Striking relationships were noted between the concentration of airborne green and blue-green algae, and meteorological conditions such as rain, vapour pressure, temperature and winds for different altitudes. In Minatitlán a linear relationship was established between concentration of algae and both vapour pressure (mbar) and temperature (° C), while in México City the wind (m s^–1) was associated with variations in the algal count.     

Effects of shading and of seasonal differences in weather on the growth, sugar content and sugar yield of sugar-beet crops

In 1967 and 1968 plots of sugar beet in two identically grown crops were shaded for successive four week periods starting on 13 June, 18 July and 22 August, and the growth of the plants compared with that on unshaded plots. At the beginning of each period in 1967 some shaded and unshaded plants received additional nitrogen, and in 1968 plants continuously shaded from June to September were compared with unshaded plants irrigated to equalize their water losses with those of the shaded plants. The weather in 1967 was sunny and dry and that in 1968 dull and wet, but the yields of dry matter, and particularly of sugar, of the unshaded crop in the 2 years were similar because, although net assimilation rate (E) was greater in 1967 than 1968, mean leaf area index (L) in 1968 was almost double that in the 1967 crop. Shading decreased the incoming radiation by 56%; it decreased E proportionally in 1967, increasing L slightly, but it decreased both E (by 44%) and L in 1968. The weights of dry matter and sugar in the roots of the shaded crop were consistently smaller at the end of shading and at final harvest in October in both years, and their weights, but not those of the tops or the whole plant, at final harvest over all shading treatments in both years were proportional to the amount of radiation received by the crop between June and September. Although shading greatly decreased the supply of photosynthate to the roots, it did not change the sugar content percentage of dry matter, except in the early stages of growth when the sugar content was rapidly increasing. Sugar content percentage of fresh weight of the roots was consistently decreased by shading, wholly because water content was increased relative to dry matter. Therefore the sugar yield of shaded plants was less because the dry weights of the roots were less, not because the partition of photosynthate between sugar storage and root growth changed. There appears to be a mechanism within the root operating over a wide range of photosynthate supply that maintains a nearly constant proportion of sucrose to non-sugar, contrary to the hypothesis that sugar stored in the roots is photosynthate in excess of what can be used in growth of the plant. However, in the extreme condition of continuous shading which drastically decreased the dry weights of all parts of the plant, sugar percentage of dry matter in the roots was decreased, but only from 80 to 70%. In 1967 extra nitrogen applied at the start of shading increased L and the dry weight of the tops in all periods, but had no effect on the dry weight of roots. Because 1968 was a wet year the irrigation treatment had no effect on E or L except for a slight increase in L during the first period; it had no effect on plant dry weight. Both irrigation and additional nitrogen decreased the sugar content percentage of fresh weight of the roots only by altering their water content; sugar percentage of dry matter was unaffected. None of these changes persisted until the final harvest in October.     

The cytotoxicity and genotoxicity of particulate and soluble hexavalent chromium in human lung cells

Hexavalent chromium (Cr(VI)) is a human lung carcinogen. Cr(VI) is a particularly important and dangerous carcinogen, because there is widespread exposure to it both occupationally and to the general public. However, despite the potential for widespread exposure and the fact that the lung is its target organ, there are few reports of the genotoxicity of Cr(VI) in human lung cells. Clearly, in order to better understand this carcinogen, its effects in its target cells need to be evaluated. Accordingly, we determined the cytotoxicity and clastogenicity of both particulate (water-insoluble) and soluble Cr(VI) in primary human bronchial fibroblasts (PHBFs). We used lead chromate (PbCrO(4)) and sodium chromate (Na(2)CrO(4)) as prototypical particulate and soluble Cr(VI) salts, respectively. Both compounds induced concentration-dependent cytotoxicity after a 24h exposure in PHBFs. The relative survival was 87, 46, 26 and 2% after exposure to 0.1, 0.5, 1 and 5 microg/cm(2) PbCrO(4), respectively, and 74, 57, 13 and 0% after exposure to 1, 2.5, 5 and 10 microM Na(2)CrO(4), respectively. Similarly, the amount of chromosome damage increased with concentration after 24h exposure to both compounds. Specifically, 0.1, 0.5 and 1 microg/cm(2) PbCrO(4) damaged 15, 34 and 42% of metaphase cells with the total amount of damage reaching 18, 40 and 66 aberrations per 100 metaphases, respectively. PbCrO(4) (5 microg/cm(2)) induced such profound cell cycle delay that no metaphases were found. Na(2)CrO(4) (1 and 2.5 microM) damaged 18 and 33% of metaphase cells with the total amount of damage reaching 19 and 43 aberrations per 100 metaphases, respectively. Na(2)CrO(4) (5 and 10 microM) induced such profound cell cycle delay that no metaphases were found. Overall the data clearly indicate that Cr(VI) compounds are cytotoxic and genotoxic to human lung cells.     

The influence of weather on the seasonal incidence of coffee berry moth,Prophantis smaragdina (Butler)

The seasonal incidence of the coffee berry moth, Prophantis smaragdina (Butler) (Lepidoptera: Pyralidae), was investigated on Coffea arabica L. in Jimma, Ethiopia. Our results showed that; the coffee berry moth was present throughout the study period except during November and December. The average incidence was 24.5% and the peak incidence (61%) was in September. Multiple correlation analysis was used to estimate the strength of association between weather variables and the incidence of the pest, and stepwise (both forward and backward) regression analysis was used to select the best explanatory variable. There were strong associations among the explanatory weather variables, indicating the potential problem of multicollinearity in the regression analysis. Relative humidity had a highly significant regression coefficient of 2.228 and was selected in the stepwise regression analysis as the best explanatory variable. The results of the study can be used in designing an integrated pest management strategy against the coffee berry moth.     

Influence of seasonal weather and climate variability on crop yields in Scotland

The climatic sensitivity of four important agriculture crops (wheat, barley, oats, potatoes) in a northern temperate bioclimatic region is investigated using national-level yield data for 1963–2005. The climate variables include monthly and annual meteorological data, derived bioclimatic metrics, and the North Atlantic Oscillation index. Statistical analysis shows that significant relationships between yield and climate vary depending on the crop type and month but highlight the influence of precipitation (negative correlation) and sunshine duration (positive correlation) rather than temperature. Soil moisture deficit is shown to be a particular useful indicator of yield with drier summers providing the best yields for Scotland as a whole. It is also tentatively inferred that the sensitivity of these crops, particularly wheat and barley, to soil moisture deficits has increased in recent years. This suggests that improved crop yields are optimised for dry sunny years despite the continued prevalence of considerable inter-annual variability in seasonal weather.     

Genotoxicity of benzo[a]pyrene, 2-nitrofluorene and airborne particulates in the DNA-repair host-mediated assay

The genotoxic activity of benzo[a]pyrene (BAP), 2-nitrofluorene (NF) and airborne particulate matter was evaluated in the DNA-repair host-mediated assay after intraperitoneal or intratracheal administration. Dimethylnitrosamine (DMNA), used as a positive control, showed a genotoxic effect after both intraperitoneal and intratracheal administration, the strongest effect being found in liver, followed by lungs and kidneys, whereas a weak effect was observed in the spleen. In general no difference in genotoxicity was found between the 2 administration routes used. For BAP, although clearly positive in vitro, a moderate dose-dependent effect was found only in the liver after intraperitoneal administration. NF, which was positive in vitro both with and without a metabolizing system, produced no genotoxic effect in any of the organs tested after intraperitoneal administration. Extracts of airborne particulate matter which were genotoxic in vitro failed to cause a genotoxic effect in vivo by either route of administration. Possible explanations for the differences between the data obtained in vitro and in vivo are discussed.     

Combination effects of chronic cadmium exposure and gamma-irradiation on the genotoxicity and cytotoxicity of peripheral blood lymphocytes and bone marrow cells in rats

This work investigated the effects of chronic cadmium (Cd) exposure combined with γ-ray irradiation on the cytotoxicity and genotoxicity of peripheral blood cells and bone marrow cells in rats. Results showed that when the rats were exposed to low dose (LD) Cd of 0.1mg CdCl?/(kgd) for 8 and 12 weeks, the Cd concentration in blood reached to 135-140 μg/L and no toxic effects on peripheral blood lymphocytes, white blood cells (WBC) and granulocyte-monocyte (GM) progenitor cells were observed except polychromatic erythrocytes (PCE) of bone marrow. Moreover, this chronic LD Cd exposure significantly decreased irradiation-induced micronucleus (MN) formation and hypoxanthine-guanine phosphoribosyl transferase (hprt) mutation in lymphocytes and PCE, while the combination of LD Cd exposure and irradiation induced the additive metallothionein (MT) protein expression in bone marrow cells. When the rats were exposed to a high dose (HD) Cd of 0.5mg CdCl/?(kgd) for 8 and 12 weeks, the blood Cd level approached to 458-613 μg/L and an inflammatory response was induced, meanwhile, MN formation and hprt mutation were markedly increased, and the ratio of PCE/NCE (normochromatic erythrocyte) was significantly decreased. Furthermore, when the rats were exposed to HD Cd plus 2 Gy irradiation, additive toxic effects on MN formation, hprt mutation, PCE damage and GM progenitor cell proliferation were observed, while this combination treatment resulted in an obvious reduction of MT protein compared to HD Cd group. In conclusion, chronic exposure to LD Cd induced the adaptive response to irradiation in the genotoxicity of peripheral blood lymphocytes and PCE of bone marrow by the up-regulation of Cd-induced MT protein, but the combination of HD Cd exposure and irradiation generated the additive effects on the cytotoxicity and genotoxicity in peripheral blood lymphocytes and bone marrow cells.     

The impact of Sharav weather conditions on airborne pollen in Jerusalem and Tel Aviv (Israel)

Pollen grains have been a major focus of research mostly in temperate regions due to their effects on human health, especially allergies and asthma. The current study investigates a subtropical region characterized by a Mediterranean climate where Sharav conditions are experienced during the spring and autumn. The aim of the current study was to investigate whether Sharav conditions impacted airborne pollen concentrations of allergenic Amaranthaceae, Poaceae, Morus, Pinus, and Quercus more than standard Warm days during the main pollen seasons in the years 2010–2014 in Tel Aviv and Jerusalem (Israel). Slight variation was observed between the main pollen seasons in Tel Aviv compared to Jerusalem resulting from differences in temperature and relative humidity percentages. Additionally, more Sharav conditions occurred in Jerusalem than in Tel Aviv during the study period. The highest pollen concentrations occurred during Sharav days for Amaranthaceae, Poaceae, and Pinus but not for Morus and Quercus. Therefore, individuals who are allergic to Amaranthaceae, Poaceae, and Pinus pollen, and exposed to high pollen concentrations during Sharav days, might suffer more allergy symptoms than on Warm days.     

Effects of PBDE-47 on cytotoxicity and genotoxicity in human neuroblastoma cells in vitro

Polybrominated diphenyl ethers (PBDEs) are an important class of flame retardants. Because of their detection in human breast milk and structural similarity to polychlorinated biphenyls (PCBs), concern has been raised about their potential toxicity, particularly neurotoxic effects in newborns and children. The aim of the current study was to evaluate the cytotoxic and genotoxic effects of 2,2',4,4'-tetrabromodiphenyl ether (PBDE-47) in human neuroblastoma (SH-SY5Y) cells in vitro. SH-SY5Y cells were incubated with different concentrations of PBDE-47 (1, 2, 4, 8 microg/ml) for 24 h, and a set of bioassays were conducted to measure: cell viability, cell proliferation (nuclear division index, NDI), lactate dehydrogenase (LDH) leakage, reactive oxygen species (ROS) formation, cell apoptosis, and DNA breakage and cytogenetic damage. The data showed that PBDE-47 inhibited cell viability, increased LDH leakage, and induced cell apoptosis. All significant effects were observed at concentrations of 4 microg/ml and above (P<0.05). After 24 h exposure, a concentration-dependent increase in ROS formation was observed, and there were obviously increase in comparison to the control at concentrations as low as 2 microg/ml PBDE-47. Log-transformed Olive Tail Moment (OTM) were significantly increased compared with the control at various PBDE-47 concentrations (P<0.05), while a significant increase in the percentage of DNA in the tail was only observed at 8 microg/ml PBDE-47 (P<0.05). PBDE-47 caused a concentration-dependent decrease in NDI, and concentration-dependent increases in chromosome abnormalities as measured by total Micronuclei (MNi)/1000 binucleate cells (BNCs), micronucleated binucleate cells (MNBNCs)/1000 BNCs, and nucleoplasmic bridges (NPBs)/1000 BNCs. The results indicate that PBDE-47 is cytotoxic and genotoxic in SH-SY5Y cells in vitro.     

The effect of local cropping activities and weather on the airborne concentration of allergenic Alternaria spores in rural Australia

Atopy to the fungus Alternaria is strongly associated with respiratory disease. The prevalences of asthma and of allergy to Alternaria are high amongst children living in rural towns of south-eastern Australia. In such towns, airborne allergenic spores have been proposed to arise from nearby crops, but this has not been tested and crops are unlikely to be the only sources of Alternaria . We sought to identify sources and factors that influence concentrations of spores of Alternaria detected in rural towns. Over two years, we sampled spores in two towns (Wagga Wagga and Moree, New South Wales, Australia), in nearby wheat and cotton crops during harvesting and control periods, in a cotton gin and a grain shed. Alternaria was present in both towns throughout the study, and above the crops, at the gin and grain shed. Daily and annual concentrations were amongst the highest recorded worldwide and peaks persisted for six months in Wagga Wagga and ten months in Moree. Crop maturation affected the spore load in the air more than the actual days of harvest. Regression analysis showed that the overall spore concentrations above towns correlated with those above crops. Variables of rainfall and maximum temperature correlated with concentrations in both towns, and additionally wind direction in Wagga Wagga. In conclusion, crops and produce handling released spores into the air that reached nearby rural towns, with peaks in spore concentrations following warm temperatures and recent rainfall.     

Bacteriological quality of crops irrigated with wastewater in the Xochimilco plots, Mexico City, Mexico

Xochimilco county plots (Mexico City), one of the most fertile agricultural areas in the Valley of Mexico, produce a large portion of the fresh vegetables consumed in the city. These plots are generally irrigated with domestic wastewater, and for this reason, it was deemed important to examine and evaluate the bacteriological quality of the water, soil, and vegetables from these plots that are harvested and marketed. The soils were also examined for the classical parameters such as nitrates, ammonia, etc., and organic matter and texture. The crops selected for this study were radishes, spinach, lettuce, parsley, and celery because they are usually consumed raw. The highest bacterial counts were encountered in leafy vegetables, i.e., spinach (8,700 for total coliform and 2,400 for fecal coliform) and lettuce (37,000 for total coliform and 3,600 for fecal coliform). Statistically significant differences in bacterial counts between rinsed and unrinsed edible portions of the crops were observed even in rinsed vegetables, and high densities of fecal coliform were detected, indicating that their consumption represents a potential health hazard. The total coliform values found in irrigation water ranged from 4 X 10(4) to 29 X 10(4), and for fecal coliform the values ranged from 5 X 10(2) to 30 X 10(2).     

Ameliorative effects of thyme and calendula extracts alone or in combination against aflatoxins-induced oxidative stress and genotoxicity in rat liver

The aims of the current work were to evaluate the hepatoprotective effect of calendula flowers and/or thyme leave extracts on aflatoxins (AFs)-induced oxidative stress, genotoxicity and alteration of p53 bax and bcl2 gene expressions. Eighty male Sprague–Dawley rats were divided into eight equal groups including: the control group, the group fed AFs-contaminated diet (2.5 mg/kg diet) for 5 weeks, the groups treated orally with thyme and/or calendula extract (0.5 g/kg b.w) for 6 weeks and the groups pretreated orally with thyme and/or calendula extract 1 week before and during AFs treatment for further 5 weeks. Blood, liver and bone marrow samples were collected for biochemical analysis, gene expression, DNA fragmentation and micronucleus assay. The results showed that AFs induced significant alterations in oxidative stress markers, increased serum AFP and inflammatory cytokine, percentage of DNA fragmentation, the expression of pro-apoptotic gene p53 and bax accompanied with a decrease in the expression of bcl2. Animals treated with the extracts 1 week before AFs treatment showed a significant decrease in oxidative damage markers, micronucleated cells, DNA fragmentation and modulation of the expression of pro-apoptotic genes. These results suggested that both calendula and thyme extracts had anti-genotoxic effects due to their higher content of total phenolic compounds.     

Optimization of airborne endotoxin exposure assessment: effects of filter type, transport conditions, extraction solutions, and storage of samples and extracts

Endotoxin exposure occurs in homes and occupational environments and is known to cause adverse health effects. In order to compare results from different studies and establish standards, airborne endotoxin exposures should be assessed using standardized methods. Although the European Committee for Standardization (CEN) developed guidelines for endotoxin exposure assessment, these leave room for individual interpretation. The influence of methods of sampling, extraction, and analysis has never been investigated in a full experimental design. Thus, we sought to fully elucidate the importance of all facets of endotoxin assessment. Inhalable dust samples collected simultaneously were used to investigate the effects on and interactions with airborne endotoxin concentration in two working environments of filter type (glass fiber or Teflon), transport conditions (with/without desiccant), sample storage (-20 or 4 degrees C), extraction solution (pyrogen-free water [PFW] or PFW plus 0.05% Tween 20), extract storage (-20 or 4 degrees C), and assay solution (PFW or PFW plus 0.05% Tween 20). Four hundred samples were collected and randomly distributed over the 20 combinations of treatments. There were no differences found for transport conditions and storage temperature of extracts. Also, no interactions between study variables existed. Sampling on glass-fiber filters, storage of samples in the freezer, and extraction in PFW plus 0.05% Tween 20 resulted in 1.3-, 1.1-, and 2.1-fold-higher estimated endotoxin concentrations, respectively. Use of PFW plus 0.05% Tween 20 in the assay solution had an additive effect. Thus, this study investigated gaps in the CEN protocol and provides data with which to fully specify a protocol for standardization of endotoxin exposure assessment.     

The effects of insulin,cycloheximide and phalloidin on the content of actin and p35 in extracts prepared from the nuclear fraction of Krebs II ascites cells

The nuclear fraction isolated from Krebs II ascites cells following cell disruption by nitrogen cavitation was separated into four fractions by salt/detergent extraction: NP-40 soluble fraction, 130 mM KCl extract, DOC/Triton × 100 soluble fraction and salt/detergent treated nuclei. The protein composition of the individual fractions was studied by SDS-PAGE and the relative amounts of actin and a 35 kDa protein (p35) were measured from gel scans. There was a time-dependent shift of actin from the 130 mM KCl extract to the NP-40 soluble fraction upon storage of the nuclear fraction on ice, indicating a progressive depolymerization of microfilaments. Compared with actin there was a slower release of p35 into the NP-40 soluble fraction. The results suggest that p35 is not integrated in the microfilament network. Phalloidin, which stabilizes the microfilaments, enriched the amount of both proteins in the 130 mM KCl extracts, together with a series of other proteins in the range 50–205 kDa. The presence of phalloidin also resulted in a large increase in the actin content in both the DOC/Triton × 100 extract and the fraction containing salt/detergent treated nuclei. Incubation of cells with insulin and/or cycloheximide enriched the amount of actin in the 130 mM KCl fraction. The results show that short term incubation of cells with phalloidin, insulin or cycloheximide increases the actin content of the nuclear fraction and also affects the presence of several other proteins.