The effect of temperature, relative humidity and rainfall on airborne ragweed pollen concentrations

Major weather parameters have long been known to alter airborne pollen and spore concentrations. The following study was conducted to study the effect of three of these parameters on airborne ragweed pollen concentrations.During the ragweed (RW) season for the years 1997 and 1998, 10 minute pollen collections were taken at least every 4 hours using an Allergenco MK-3 spore trap. Slides were fixed, and counted microscopically at 400X. During this same period, weather parameters were monitored by an Automated Weather Systems recording station located within a few meters of the collector.The ragweed season for this region begins in mid August and ends by mid October. Temperature patterns for the period demonstrated usual daily fluctuations with highs 13 to 35 °C and lows 8 to 24 °C. Relative humidity readings for the period varied between 25 and 100%. Highest RW values were seen after seasonal cooling in September. Daily rainfall for the period varied between 0 and 100 mm. Airborne RW always declined sharply after strong rainfall events (> 10 mm/day). Peak airborne RW concentrations were often associated with the passing of frontal boundaries and the change in wind direction and velocity that accompanies that passing.Factors influencing airborne RW concentrations are multiple and complex, but atmospheric forces have great influence. The passing of major weather fronts and the associated temperature drops, wind disturbances and rainfall are the major factors.     

The effect of glycosaminoglycans with acetaldehyde on the activation of prothrombin

Heparin17-19k, (25, 50, and 100 ng), heparin6k (50 and 100 ng), heparin3k (50, 100, and 200 microg), chondroitin sulfates B (dermatan sulfate) (0.25, 0.5, and 1.0 microg), C (1 and 10 microg), and A (1 and 10 microg) each prolong the activated partial thromboplastin time (APTT) when preincubated with prothrombin to a greater extent than when preincubated with Factor II-deficient plasma prior to their mixing and subsequent additions of APTT reagent and Ca2+. In all cases statistical significance (p < or = 0.05) was observed except with the 2 lower levels of heparin3k. These results suggest that the glycosaminoglycans (GAGs) may exert a direct effect upon prothrombin (FII) in their anticoagulant activity. Pre mix tures of [(FII/25 ng H17-19k) + 447 mmol acetaldehyde (AcH)/L] as well as [(AcH/H) + FII] and [(FII/AcH) + H] each exert a synergistic anticoagulant effect upon APTT. At low AcH concentrations (44.7 mmol/L), neither a synergistic nor an additive effect is seen. H6k and H3k, on premixing with 447 mmol AcH/L, exhibit an additive effect on APTT prolongation but no synergism. Similarly, premixtures of CSB/447 mmol AcH/L/FII show a greater anticoagulant effect than do [(CSB/AcH) + FII] or [(FII/AcH) + CSB] premixtures. CSC-AcH and CSA-AcH patterns are analogous to those of CSB (DS). These data suggest the possibility that AcH, the primary product of ethanol metabolism, may serve as a crosslinking adduct with proteins, in this case, prothrombin, as well as GAGs. Thus ternary complexes between the zymogen form of coagulation factors, GAGs, and AcH are possible, further influencing coagulopathy.     

The effect of light direction and suspended cell concentrations on algal biofilm growth rates

Algae biofilms were grown in a semicontinuous flat plate biofilm photobioreactor to study the effects of light direction and suspended algal cell populations on algal biofilm growth. It was determined that, under the growth conditions and biofilm thicknesses studied, light direction had no effect on long-term algal biofilm growth (26 days); however, light direction did affect the concentration of suspended algal cells by influencing the photon flux density in the growth medium in the photobioreactors. This suspended algal cell population affected short-term (7 days) algae cell recruitment and algal biofilm growth, but additional studies showed that enhanced suspended algal cell populations did not affect biofilm growth rates over the long term (26 days). Studying profiles of light transmittance through biofilms as they grew showed that most of the light became attenuated by the biomass after just a few days of growth (88 % after 3 days). The estimated biofilm thicknesses after these few days of growth were approximately 150 μm. The light attenuation data suggests that, although the biofilms grew to 700–900 μm, under these light intensities, only the first few hundred micrometers of the biofilm is receiving enough light to be photosynthetically active. We postulate that this photosynthetically active layer of the biofilm grows adjacent to the light source, while the rest of the biofilm is in a stationary growth phase. The results of this study have implications for algal biofilm photobioreactor design and operation.     

The effect of temperature and relative humidity on the formation of Metarhizium anisopliae chlamydospores in tick eggs

The influence of ambient conditions on the development of Metarhizium anisopliae chlamydospores in tick eggs is reported for the first time. The infection of tick eggs by M. anisopliae involves common events, such as adhesion, conidial germination, appressoria formation, invasion, and development within the eggs. However, the final stage of fungal development differs according to the environmental conditions. At high humidity (close to 100%) and moderate temperature (25°C) the fungus emerged from the eggs and formed conidiophores and conidia externally on the dead eggs. Elevating the temperature to 30°C or reducing humidity to 55-75% induced the production of chlamydospores inside the eggs, without conidiogenesis. When eggs with mature chlamydospores were returned to the appropriate conditions (25°C and 100% RH), conidiogenesis was recovered. Formation of chlamydospores, observed by means of histology and TEM, began with the thickening and septation of hyphae. As the chlamydospore wall thickened a new external undulated wall layer appeared. The mature chlamydospore in eggs has an oval shape (5.3 ± 0.9 microm long, 2.5 ± 0.2 microm wide); its wall comprises three distinct layers. The ability of M. anisopliae to produce chlamydospores under harsh conditions is advantageous and should be considered in application.     

Blood concentrations of acetaldehyde during chlorpropamide-alcohol flush.

To test the suggestion that chlorpropamide-alcohol flushing (CPAF) resembles the disulfiram effect and might be mediated by acetaldehyde, the initial metabolite of alcohol, blood concentrations of acetaldehyde were measured after a drink of alcohol in controls and diabetics positive and negative for CPAF. The CPAF-positive diabetics had significantly greater blood acetaldehyde concentrations after alcohol than the CPAF-negative diabetics both with a single dose of chlorpropamide and after two weeks'' chlorpropamide treatment. Concentrations in the CPAF-positive group after chlorpropamide were also significantly greater than after a placebo tablet. There was also a clear separation in the increase in facial temperature after two weeks of chlorpropamide between the CPAF-positive and CPAF-negative groups (although there was some overlap after a single tablet). There was no difference in plasma chlorpropamide or alcohol concentrations between CPAF-positive and CPAF-negative diabetics. These findings show that CPAF is distinct from alcohol flushing and that the acetaldehyde concentration in the blood provides an objective measure of CPAF. The difference between flushing and non-flushing diabetics cannot be accounted for by differences in blood concentrations of chlorpropamide or alcohol.     

The measurement of the Bohr effect of fish hemoglobins by gel electrofocusing

• 1. Hemolysates from 16 species of Amazon fish and one amphibian were analyzed by gel electrofocusing. The change in isoelectric point upon deoxygenation provided a reliable estimate of the Bohr effect.
• 2. Certain species of fish had single hemoglobin components whose pI increased significantly upon deoxygenation, as in man. Other fish had hemoglobins whose isoelectric points were unaffected by deoxygenation. Six species of fish had at least two hemoglobin components, one of which had a reduced isoelectric point upon deoxygenation indicating a reversed Bohr effect, whereas the other(s) had an increased isoelectric point on deoxygenation, as occurs with the normal alkaline Bohr effect.
• 3. A close correlation was found between the change in isoelectric point with deoxygenation and the Bohr effect determined by oxygen equilibrium measurements.

     

The effect of calcium on the oxidation of acetaldehyde by rat liver mitochondria.

Isolated liver mitochondria oxidized acetaldehyde in the following order: State 4< state 3< valinomycin. Ca²⁺, in concentrations greater than 0.10 mM, inhibited the oxidation of acetaldehyde by isolated liver mitochondria under all conditions. Valinomycin-stimulated oxidation of acetaldehyde was more sensitive to inhibition by Ca²⁺ than were the state 3 or 4 rates of acetaldehyde oxidation. Acetaldehyde could support an energy-dependent uptake of Ca²⁺ at rates about 20 percent that found with succinate. Ruthenium red, an inhibitor of Ca²⁺ translocation, almost completely prevented the inhibition by Ca²⁺, under all conditions. The addition of externally added NAD⁺ or NADH provided complete relief against the inhibitions by Ca²⁺ of the state 4 and 3 rates of acetaldehyde oxidation. Although some relief was also observed with the valinomycin-stimulated system, significant inhibition persisted. Cations such as Zn²⁺, Cu²⁺, or Hg²⁺ also inhibited acetaldehyde oxidation, whereas Mg²⁺ and Mn²⁺ were without effect. These cations also blocked glutamate oxidation and presumably inhibit acetaldehyde oxidation by preventing reoxidation of NADH. The greater sensitivity of the ionophore-stimulated oxidation of acetaldehyde to inhibition by Ca²⁺ may reflect release of intramitochondria K⁺, which is known to occur in the presence of Ca²⁺, suggesting that acetaldehyde oxidation is influenced by the cation environment within the mitochondria.     

The effect of a decrease in cerebral noradrenaline concentrations on the formation and fixation of temporary connections]

A sharp drop in the noradrenaline content (Na) in the brain of mice does not prevent the elaboration and fixation of relatively simple conditioned reflexes, but considerably disturbs the elaboration of more complex conditioned reflexes with delayed reinforcement. The decrease in the NA content in the brain does not appear to influence directly the process of consolidation of temporary connections; impaired fixation of relatively more complex forms of temporary connections is of a secondary nature and is due to disturbances in their formation.     

Role of tertiary structures on the Root effect in fish hemoglobins

Many fish hemoglobins exhibit a marked dependence of oxygen affinity and cooperativity on proton concentration, called Root effect. Both tertiary and quaternary effects have been evoked to explain the allosteric regulation brought about by protons in fish hemoglobins. However, no general rules have emerged so far. We carried out a complementary crystallographic and microspectroscopic characterization of ligand binding to crystals of deoxy-hemoglobin from the Antarctic fish Trematomus bernacchii (HbTb) at pH 6.2 and pH 8.4. At low pH ligation has negligible structural effects, correlating with low affinity and absence of cooperativity in oxygen binding. At high pH, ligation causes significant changes at the tertiary structural level, while preserving structural markers of the T state. These changes mainly consist in a marked displacement of the position of the switch region CD corner towards an R-like position. The functional data on T-state crystals validate the relevance of the crystallographic observations, revealing that, differently from mammalian Hbs, in HbTb a significant degree of cooperativity in oxygen binding is due to tertiary conformational changes, in the absence of the T–R quaternary transition. This article is part of a Special Issue entitled: Oxygen Binding and Sensing Proteins.     

Effect of acetaldehyde on the formation of alcohol dependence in animal experiments]

As a result of the experiment on the laboratory animals under the continuous administration of acetaldehyde there has been revealed the latter as inducing the aldehyde dehydrogenase activity in the cytosol fraction of the cerebral structures/hypothalamus, mid-brain and new cerebrum cortex/as well as in the levels of biogenic amines/noradrenaline and 5-hydroxytryptamine/in the same structures while forming experimentally in the laboratory animals the alcoholic dependence under acetaldehyde alcoholic dependence. The work displays some changes of alcohol dehydrogenase and action.     

The unusual effect of pKM101 on the mutagenicity of acetaldehyde oxime in Salmonella typhimurium

Acetaldehyde oxime was found to induce more revertants in Salmonella typhimurium strain TA1535 than in TA100 in the absence of S9 metabolic activation. TA100 was originally constructed from TA1535 by the addition of the plasmid pKM101, carrying mucAB which generally enhances sensitivity to the mutagenic effects of chemicals. The role of pKM101 in lowering the sensitivity to acetaldehyde oxime was explored by: (1) increasing the incubation time of the selective agar plates from 2 to 3 days; (2) using a new strain, isogenic to TA100, constructed by introducing pKM101 into the TA1535 isolate used in these experiments; (3) by testing a strain constructed by inserting into TA1535 a plasmid carrying mucAB but otherwise unrelated to pKM101. Each of these alterations increased the number of revertants per plate in the presence of acetaldehyde oxime, indicating that the apparent nonmutagenicity of this chemical in TA100 is due to multiple factors.