Effect of root anaerobiosis on the water relations of several Pyrus species

Solution culture experiments were designed to investigate the plant water relations of 3 Pyrus species subjected to root anaerobiosis. Root anaerobiosis induced partial stomatal closure prior to alterations in leaf water potential (ΨLW) or root osmotic potential (ΨRπ). In contrast, stomatal closure was accompanied by a decline in root hydraulic conductivity (Lp). Anoxia markedly reduced ΨLW for Pyrus communis L. and eventually led to wilting and defoliation. Pyrus betulaefolia Bunge and Pyrus calleryana Decne, however, were less affected by root anaerobiosis. To delineate if the increased root resistance was in the radial or longitudinal direction, 10⁻⁴ M cistrans abscisic acid (ABA) was added to detopped root systems of P. communis in solution culture after steady-state rates of Lp were established. A consistent 25 to 30% promotion of Lp was observed 1.5 h after the addition of ABA for aerobically treated plants. ABA did not influence Lp when applied to roots previously deprived of O₂ for 4 days. Additional evidence against the limiting resistance being in the radial direction was obtained when water fluxes were compared through intact P. communis roots, roots with all feeder roots detached, and stems without root systems. Severing feeder roots from anaerobically treated plants did not increase water flux to rates observed for aerobically treated plants. Resistance progressed basipetally to eventually encompass the stem itself. These results can only be explained by occlusion of the xylem vessels.     

Hazard Inherent in Microbial Tracers: Reduction of Risk by the Use of Bacillus stearothermophilus Spores in Aerobiology

The use of a „biological tracer” forms an essential part of many aerobiological experiments. Where release of such tracers is likely to result in deliberate or inadvertent human exposure, safety becomes a primary consideration in the selection of the tracer organism. Of the three most commonly used organisms, namely Bacillus subtilis, Escherichia coli, and Serratia marcescens, only the first comes near to satisfying the need for nonpathogenicity and even it has been incriminated as a cause of human infection, sometimes with a fatal outcome. The relevant characteristics of B. stearothermophilus were, therefore, investigated. Because it can grow only at elevated temperatures (minimum 41 C; optimum 56 C), it should not pose a threat to human health and this view is supported by experimental evidence to be presented. It is extremely easy to grow and maintain in the laboratory, and spore suspensions are easily prepared and stored. It withstands the stresses of aerosolization and sampling and its stability in the aerosol state compares favorably with that of B. subtilis var. niger.     

Effect of regional climate warming on the phenology of butterflies in boreal forests in Manitoba, Canada

We examined the effect of regional climate warming on the phenology of butterfly species in boreal forest ecosystems in Manitoba, Canada. For the period 1971-2004, the mean monthly temperatures in January, September, and December increased significantly, as did the mean temperatures for several concurrent monthly periods. The mean annual temperature increased ≈ 0.05°C/yr over the study period. The annual number of frost-free days and degree-day accumulations increased as well. We measured the response of 19 common butterfly species to these temperature changes with the date of first appearance, week of peak abundance, and the length of flight period over the 33-yr period of 1972-2004. Although adult butterfly response was variable for spring and summer months, 13 of 19 species showed a significant (P < 0.05) increase in flight period extending longer into the autumn. Flight period extensions increased by 31.5 ± 13.9 (SD) d over the study period for 13 butterfly species significantly affected by the warming trend. The early autumn and winter months warmed significantly, and butterflies seem to be responding to this warming trend with a change in the length of certain life stages. Two species, Junonia coenia and Euphydryas phaeton, increased their northerly ranges by ≈ 150 and 70 km, respectively. Warmer autumns and winters may be providing opportunities for range extensions of more southerly butterfly species held at bay by past climatic conditions.     

Experimental stress in inflammatory rheumatic diseases: a review of psychophysiological stress responses

Introduction  

Stressful events are thought to contribute to the aetiology, maintenance and exacerbation of rheumatic diseases. Given the growing interest in acute stress responses and disease, this review investigates the impact of real-life experimental psychosocial, cognitive, exercise and sensory stressors on autonomic, neuroendocrine and immune function in patients with inflammatory rheumatic diseases.     

Menin links the stress response to genome stability in Drosophila melanogaster

Background

The multiple endocrine neoplasia type I gene functions as a tumor suppressor gene in humans and mouse models. In Drosophila melanogaster, mutants of the menin gene (Mnn1) are hypersensitive to mutagens or gamma irradiation and have profound defects in the response to several stresses including heat shock, hypoxia, hyperosmolarity and oxidative stress. However, it is not known if the function of menin in the stress response contributes to genome stability. The objective of this study was to examine the role of menin in the control of the stress response and genome stability.

Methodology/Principal Findings

Using a test of loss-of-heterozygosity, we show that Drosophila strains lacking a functional Mnn1 gene or expressing a Mnn1 dsRNA display increased genome instability in response to non-lethal heat shock or hypoxia treatments. This is also true for strains lacking all Hsp70 genes, implying that a precise control of the stress response is required for genome stability. While menin is required for Hsp70 expression, the results of epistatic studies indicate that the increase in genome instability observed in Mnn1 lack-of-function mutants cannot be accounted for by mis-expression of Hsp70. Therefore, menin may promote genome stability by controlling the expression of other stress-responsive genes. In agreement with this notion, gene profiling reveals that Mnn1 is required for sustained expression of all heat shock protein genes but is dispensable for early induction of the heat shock response.

Conclusions/Significance

Mutants of the Mnn1 gene are hypersensitive to several stresses and display increased genome instability when subjected to conditions, such as heat shock, generally regarded as non-genotoxic. In this report, we describe a role for menin as a global regulator of heat shock gene expression and critical factor in the maintenance of genome integrity. Therefore, menin links the stress response to the control of genome stability in Drosophila melanogaster.     

Optimisation of 2-cyano-pyrimidine inhibitors of cathepsin K: Improving selectivity over hERG

Several structure-guided optimisation strategies were explored in order to improve the hERG selectivity profile of cathepsin K inhibitor 1, whilst maintaining its otherwise excellent in vitro and in vivo profile. Ultimately, attenuation of c log P and pK_a properties proved a successful approach and led to the discovery of a potent analogue 23, which, in addition to the desired selectivity over hERG (>1000-fold), displayed a highly attractive overall profile.     

Influence of body heat content on hand function during prolonged cold exposures.

We examined the influence of 1) prior increase [preheating (PHT)], 2) increase throughout [heating (HT)], and 3) no increase [control (Con)] of body heat content (H(b)) on neuromuscular function and manual dexterity of the hands during a 130-min exposure to -20 degrees C (coldEx). Ten volunteers randomly underwent three passive coldEx, incorporating a 10-min moderate-exercise period at the 65th min while wearing a liquid conditioning garment (LCG) and military arctic clothing. In PHT, 50 degrees C water was circulated in the LCG before coldEx until core temperature was increased by 0.5 degrees C. In HT, participants regulated the inlet LCG water temperature throughout coldEx to subjective comfort, while the LCG was not operating in Con. Thermal comfort, rectal temperature, mean skin temperature, mean finger temperature (T(fing)), change in H(b) (DeltaH(b)), rate of body heat storage, Purdue pegboard test, finger tapping, handgrip, maximum voluntary contraction, and evoked twitch force of the first dorsal interosseus muscle were recorded. Results demonstrated that, unlike in HT and PHT, thermal comfort, rectal temperature, mean skin temperature, twitch force, maximum voluntary contraction, and finger tapping declined significantly in Con. In contrast, T(fing) and Purdue pegboard test remained constant only in HT. Generalized estimating equations demonstrated that DeltaH(b) and T(fing) were associated over time with hand function, whereas no significant association was detected for rate of body heat storage. It is concluded that increasing H(b) not only throughout but also before a coldEx is effective in maintaining hand function. In addition, we found that the best indicator of hand function is DeltaH(b) followed by T(fing).