Effects of experimental warming on survival,phenology, and morphology of an aquatic insect (Odonata)

1. Organisms can respond to changing climatic conditions in multiple ways including changes in phenology, body size or morphology, and range shifts. Understanding how developmental temperatures affect insect life‐history timing and morphology is crucial because body size and morphology affect multiple aspects of life history, including dispersal ability, whereas phenology can shape population performance and community interactions. 2. It was experimentally assessed how developmental temperatures experienced by aquatic larvae affected survival, phenology, and adult morphology of dragonflies [Pachydiplax longipennis (Burmeister)]. Larvae were reared under three environmental temperatures: ambient, +2.5, and +5 °C, corresponding to temperature projections for our study area 50 and 100 years in the future, respectively. Experimental temperature treatments tracked naturally‐occurring variation. 3. Clear effects of temperature were found in the rearing environment on survival and phenology: dragonflies reared at the highest temperatures had the lowest survival rates and emerged from the larval stage approximately 3 weeks earlier than animals reared at ambient temperatures. There was no effect of rearing temperature on overall body size. Although neither the relative wing nor thorax size was affected by warming, a non‐significant trend towards an interaction between sex and warming in relative thorax size suggests that males may be more sensitive to warming than females, a pattern that should be investigated further. 4. Warming strongly affected survival in the larval stage and the phenology of adult emergence. Understanding how warming in the developmental environment affects later life‐history stages is critical to interpreting the consequences of warming for organismal performance.     

Improved design of peptides exhibiting angiogenic activities for clinical applications

Vascularization is one of the key steps for engraftment in regenerative medicine. Previously one of the authors had discovered peptides exhibiting significant angiogenic activities designated AGP and elucidated the active core. For neovascularization basic fibroblast growth factor is used although permeation can be envisaged. The original AGPs did not suffer from this although their half-life times are short because of decomposition by endogenous enzymes. Several new AGP-libraries have been constructed and their enzymatic resistance has been investigated by the use of human umbilical vein endothelial cells to find candidates for clinical applications.     

Glyceraldehyde-3-phosphate dehydrogenase from Thermotoga maritima: Strategies of protein stabilization

Abstract: The molecular origin of protein stability has been the subject of active research for more than a generation (R. Jaenicke (1991) Eur. J. Biochem. 202, 715–728). Faced with the discovery of extremophiles, in recent years the problem has gained momentum, especially because of its biotechnological potential. In analyzing a number of enzymes from the hyperthermophilic bacterium Thermotoga maritima , it has become clear that the excess free energy of stabilization is equivalent to only a few weak bonds ( ΔΔG _stab≈ 50 kJ/mol). As taken from the comparison of homologous enzymes from mesophiles, thermophiles and hyperthermophiles, these accumulate from local interactions (especially ion pairs), enhanced secondary or supersecondary structure, and improved packing of domains and/or subunits, without significantly altering the overall topology. In this review, glyceraldehyde-3-phosphate dehydrogenase will be discussed as a representative example to illustrate possible adaptive strategies to the extreme thermal stress in hydrothermal vents.     

Fluctuating environments impact thermal tolerance in an invasive insect species Bactrocera dorsalis (Diptera: Tephritidae)

The incidence and severity of environmental stressors associated with global climate change are increasing and insects frequently face variability in temperature and moisture regimes at variable spatio-temporal scales. Coincidental with this, is increased thermal and hydric stress on insects as warming increases vapour pressure deficit (VPD), the drying power of the air. While the effects of mean temperatures on fitness are widely documented, fluctuations in both temperature and relative humidity (RH) are largely unexplored. Here, we investigated the effects of dynamic temperature and RH fluctuations (around the mean [28°C; 65% RH]) on low and high thermal tolerance of laboratory-reared adult invasive Bactrocera dorsalis (Hendel) (Diptera: Tephritidae), measured as critical thermal minima (CT_min), critical thermal maxima (CT_max), chill coma recovery time (CCRT) and heat knockdown time (HKDT). Our results show that increased environmental amplitude significantly influenced low and high temperature responses and varied across traits tested. The highest amplitude (δ12°C; 28% RH) compromised CT_min, CCRT and HKDT traits while enhancing CT_max. Similarly, acclimation to δ3°C; 7% RH compromised both low (CT_min and CCRT) and high (CT_max and HKDT) fitness traits. Variations in fitness reported here indicate significant roles of combined thermal and moisture fluctuations on B. dorsalis fitness suggesting caveats that are worthy considering when predicting species responses to climate change. These results are significant for B. dorsalis population phenology, management, quantifying vulnerability to climate variability and may help modelling future biogeographical patterns.     

Fate of transformed Trichoderma harzianum in the phylloplane of tomato plants

A propiconazole-resistant Trichoderma harzianum strain with high phylloplane survival capability was transformed with the E. coli hygromycin B phosphotransferase gene (hph), coding for hygromycin B resistance. Four transformants were analysed for survival ability on the phylloplane of tomato plants grown under glasshouse conditions in comparison with their prototype and a yellow, hygromycin B-sensitive mutant. Over 2 weeks, the four transformants showed higher survival rates in comparison with the wild-type strain. The yellow mutant TF3/973 did not significantly differ in survival from the transformants. Both hygromycin B resistance and mitotic stability of transformants were evaluated during growth in vitro and after reisolation from tomato phylloplane. Hybridization patterns with the complete plasmid indicated that all four transformants were mitotically stable after several rounds of vegetative growth without selective pressure and during 2 weeks on tomato plants. None of the transformants had lost the ability to grow in the presence of both propiconazole and hygromycin B after growth under the same conditions. The results are discussed in relation to risk assessment of the release of transgenic fungi.     

A twofold role for global energy gradients in marine biodiversity trends

Explanations for major biodiversity patterns have not achieved a consensus, even for the latitudinal diversity gradient (LDG), but most relate to patterns of solar energy influx into Earth systems, and its effects on temperature (as biochemical activity rates are temperature sensitive) and photosynthesis (which drives nearly all of the productivity that fuels ecosystems). Marine systems break some of the confounding correlations among temperature, latitude and biodiversity that typify the terrestrial systems that have dominated theoretical discussions and large‐scale analyses. High marine diversities occur not only in warm shallow seas where productivity may be either low or high, depending on regional features, but also in very cold deep‐sea regions, indicating that diversity is promoted by stability in temperature and in trophic resources (nutrients and food items), and more specifically by their interaction, rather than by high mean values of either variable. The common association of high diversity with stable but low to moderate annual productivity suggests that ecological specialization underlies the similarly high diversities in the shallow tropics and deep sea. Recent work on shallow‐marine bivalves is consistent with this view of decreasing specialization in less stable habitats. Lower diversities in shallow seas are associated with either high thermal seasonality (chiefly in temperate latitudes) or highly seasonal trophic supplies (at any latitude), which exclude species that are adapted to narrow ranges of those variables.     

Screening of thermotolerant yeasts as producers of superoxide dismutase

Abstract A screening procedure for highly thermostable yeast superoxide dismutase was developed. Growth yields at various temperatures were estimated for ten mesophilic and thermotolerant strains, belonging to the genera Saccharomyces, Kluyveromyces and Pichia . Higher yields at 45°C were obtained for K. lactis 90-3 and 90-4. A correlation between the ability to grow at higher temperature and the thermostability of the superoxide dismutase enzyme synthesized was observed. A comparison of the operational stability of the superoxide dismutase of all tested strains suggests that the enzyme of K. lactis strains was more thermostable than that of the other tested microorganisms.