Hyperactive spruce budworm antifreeze protein expression in transgenic Drosophila does not confer cold shock tolerance

Drosophila melanogaster, a freeze intolerant and cold shock sensitive insect, was transformed with the hyperactive insect antifreeze protein gene (AFP) from the spruce budworm, Choristoneura fumiferana. Transformation P-element constructs (pCasper) were made with CfAFP 337 isoform DNA using a strong constitutive promoter, Actin 5c. This is the first report of insect AFP used to transform another insect. Properly folded active insect AFP was only detected when signal sequences were used to target proteins to the endoplasmic reticulum for secretion into the hemolymph. The 18 residue Drosophila binding protein signal sequence (BiP) constructs resulted in transformed fly lines with significantly higher AFP expression in hemolymph than when the native C. fumiferana AFP signal sequence was used. The resultant transgene fly lines have the highest levels of thermal hysteresis, 0.8 degrees C, seen for any engineered Drosophila. Despite the high level of expression, even higher than some overwintering fish with natural levels of endogenous AFP, the transformants did not display any cold shock resistance compared to controls or low AFP expressing lines. These results indicate that insect AFP alone cannot protect Drosophila from cold shock and may not be useful for Drosophila cryopreservation.     

Meteorological factors and the onset of hypertensive intracerebral hemorrhage

There have been numerous studies of the relationship between intracerebral hemorrhage (ICH) and meteorological conditions, but their conclusions have been inconsistent. Poor discrimination of ICH subtypes (primary or secondary) may have obscured the conclusions. Although most studies have analyzed seasonal or monthly variation, daily meteorological data are more appropriate for determining whether weather conditions play a role in triggering the onset of ICH. No studies have examined the activity and location of patients at the time of onset. The aim of this study was to evaluate the relationship between the occurrence of hypertensive ICH and daily meteorological parameters, in addition to examining the effect of the location and activity of the patient at the time of onset. We analyzed 138 patients with severe hypertensive ICH in a hospital-based population. We assessed whether daily meteorological parameters for the days on which ICH occurred differed from the days without ICH onset. Days on which hypertensive ICH occurred had a significantly lower minimum temperature and a decreased minimum temperature from that of the previous day (P=0.0042 and 0.0012, respectively). There were no significant differences among subgroups of patients categorized according to their location and activity at the time of onset for any of the meteorological parameters.An erratum to this article can be found at     

Ontogenetic correlates of diet in Malagasy lemurs

There is a well-documented relationship between development and other life-history parameters among anthropoid primates. Smaller-bodied anthropoids tend to mature more rapidly than do larger-bodied species. Among anthropoids of similar body sizes, folivorous species tend to grow and mature more quickly than do frugivorous species, thus attaining adult body size at an earlier age. This pattern conforms to the expectations of Janson and van Schaik's "ecological risk aversion hypothesis," which predicts that rates of growth and maturation should vary in inverse relation to the intensity of intraspecific feeding competition. According to the ecological risk aversion hypothesis (RAH), species experiencing high intraspecific feeding competition will grow and mature slowly to reduce the risk of mortality due to food shortages. Species experiencing low levels of intraspecific feeding competition will shorten the juvenile period to reduce the overall duration of this high-risk portion of the life cycle. This paper focuses on development and maturation in lemurs. We show that folivorous lemurs (such as indriids) grow and mature more slowly than like-sized frugivorous lemurs (e.g., most lemurids), but tend to exhibit faster dental development. Their dental developmental schedules are accelerated on an absolute scale, relative to craniofacial growth, and relative to particular life-history landmarks, such as weaning. Dental development has a strong phylogenetic component: even those lemurids that consume substantial amounts of foliage have slower dental development than those indriids that consume substantial amounts of fruit. Implications of these results for the RAH are discussed, and an explanation for this hypothesis' failure to predict lemur growth schedules is offered. We propose that the differing developmental schedules of folivorous and frugivorous lemurs may reflect different solutions to the ecological problem of environmental instability: some rely on a strategy of low maternal input and slow returns, while others rely on a strategy of high maternal input and fast returns.     

Low temperature-induced systems failure in Escherichia coli: insights from rescue by cold-adapted chaperones

The growth of Escherichia coli cells is impaired at temperatures below 21 degrees C and stops at 7.5 degrees C; however, growth of a transgenic strain producing the cold-adapted chaperones Cpn60 and Cpn10 from the psychrophilic bacterium Oleispira antarctica is good at low temperatures. The E. coli cpn(+) transgene offers a novel opportunity for examining the essential protein for cell viability at low temperatures. By screening a large-scale protein map (proteome) of cells of K-12 and its Cpn(+) transgene incubated at 4 degrees C, we identified 22 housekeeping proteins involved in systems failure of E. coli when confronted with low temperature. Through co-immunoprecipitation of Cpn60, Northern blot, and in vitro refolding, we systematically identified that protein-chaperone interactions are key determinants of their protein functions at low temperatures. Furthermore, chromosomal gene deletion experiments suggest that the mechanism of cold-induced systems failure in E. coli is cold-induced inactivation of the GroELS chaperonins and the resulting failure to refold cold-inactivated Dps, ClpB, DnaK and RpsB proteins. These findings: (1) indicate the potential importance of chaperones in cold sensitivity, cold adaptation and cold tolerance in cellular systems, and (2) suggest the identity of a few key cold-sensitive chaperone-interacting proteins that get inactivated and ultimately cause systems failure in E. coli cells at low temperatures.     

Cold tolerance of the harlequin ladybird Harmonia axyridis in Europe

As an essential aspect of its invasive character in Europe, this study examined the cold hardiness of the harlequin ladybird Harmonia axyridis. This was done for field-collected populations in Belgium overwintering either in an unheated indoor or an outdoor hibernaculum. The supercooling point, lower lethal temperature and lower lethal time at 0 and −5 °C were determined. Possible seasonal changes were taken into account by monitoring the populations during each winter month. The supercooling point and lower lethal temperature remained relatively constant for the overwintering populations in the outdoor hibernaculum, ranging from −17.5 to −16.5 °C and −17.1 to −16.3 °C, respectively. In contrast, the supercooling point and lower lethal temperature of the population overwintering indoors clearly increased as the winter progressed, from −18.5 to −13.2 °C and −16.7 to −14.1 °C, respectively. A proportion of the individuals overwintering indoors could thus encounter problems surviving the winter due to premature activation at times when food is not available. The lower lethal time of field populations at 0 and −5 °C varied from 18 to 24 weeks and from 12 to 22 weeks, respectively. Morph type and sex had no influence on the cold hardiness of the overwintering adults. In addition, all cold tolerance parameters differed greatly between the laboratory population and field populations, implying that cold tolerance research based solely on laboratory populations may not be representative of field situations. We conclude from this study that the strong cold hardiness of H. axyridis in Europe may enable the species to establish in large parts of the continent.     

Airborne fungal spores in urban and rural environments in Poland

The concentrations of airborne fungal spores were measured during 2001–2002 in two sites in Poland—one in the city and the other in the countryside. The sites differed in habitat characteristics, such as urbanisation level, vegetation and microclimate. The aim of the study was to determine if, and in which way, land use type would affect spore occurrence. The volumetric method was used, and ten easily identifiable spore types were sampled and anyalysed: Alternaria, Botrytis, Cladosporium, Epiccocum, Ganoderma, Pithomyces, Polythrincium, Stemphylium, Torula and Drechslera. The season of spore occurrence was determined using the 90% method. The fungal spores studied were very frequent in the air (in most instances at a frequency higher than 50%). The most common spores were those of Cladosporium, with a frequency range of 83.1–90.5%. In both years the proportion of Cladosporium spores was statistically significantly higher in the city. In both 2001 and 2002 the total seasonal sum of all the spores was higher in the countryside than in the city as was the Seasonal Fungal Index (SFI) values and average concentrations of Botrytis, Ganoderma and Torula. These latter three genera are usually represented as pathogens of plants. The mean spore concentrations of most taxa were significantly higher in the rural environment. Correlation coefficients between daily concentrations at both sites for most of the taxa studied were significant, but with lower correlation values between variables. Such results indicate that the values from the sites are weakly interdependent. The study confirms that land use type may very likely have an impact on the course of spore occurrence, the mean daily concentrations of spores as well as SFI values.     

Responses of antennal campaniform sensilla to rapid temperature changes in ground beetles of the tribe platynini with different habitat preferences and daily activity rhythms

Responses of temperature sensitive (cold) cells from the antenna of ground beetles (tribe Platynini) were compared in species with different ecological preferences and daily activity rhythms. Action potential rates were characterized at various temperatures (ranges 23-39 degrees C) and during rapid changes in it (Deltat=0.5-15 degrees C). The stationary firing frequencies were nearly twice as high in eurythermic open field ground beetles Agonum muelleri and Anchomenus dorsalis (firing rates ranging from 22 to 47imp/s) than in a stenothermic forest species Platynus assimilis. In the eurythermic species, the firing rate did not significantly depend on temperature (Anchomenus dorsalis range of 23-27 degrees C and Agonum muelleri range of 23-33 degrees C) but plots of firing rate versus temperature showed rapid declines when lethally high temperatures were approached. In contrast, a nearly linear decline of the firing rate/temperature curve was observed in Platynus assimilis. Responses to rapid temperature decreases were also considerably higher in eurythermic species. Both the peak frequency of the initial burst (maximum 420-650Hz) as well as the sustained discharge in the first 4s of the response were higher than in Platynus assimilis. Long silent periods, lasting up to several seconds, that occurred at the beginning of the response to rapid warming were significantly shorter in Agonum muelleri and Anchomenus dorsalis compared to Platynus assimilis. These findings suggest that the responses of thermoreceptors to temperature changes may be correlated with specific ecological preferences.     

Genome-wide expression analysis of yeast response during exposure to 4°C

Adaptation to temperature fluctuation is essential for the survival of all living organisms. Although extensive research has been done on heat and cold shock responses, there have been no reports on global responses to cold shock below 10°C or near-freezing. We examined the genome-wide expression in Saccharomyces cerevisiae, following exposure to 4°C. Hierarchical cluster analysis showed that the gene expression profile following 4°C exposure from 6 to 48 h was different from that at continuous 4°C culture. Under 4°C exposure, the genes involved in trehalose and glycogen synthesis were induced, suggesting that biosynthesis and accumulation of those reserve carbohydrates might be necessary for cold tolerance and energy preservation. The observed increased expression of phospholipids, mannoproteins, and cold shock proteins (e.g., TIP1) is consistent with membrane maintenance and increased permeability of the cell wall at 4°C. The induction of heat shock proteins and glutathione at 4°C may be required for revitalization of enzyme activity, and for detoxification of active oxygen species, respectively. The genes with these functions may provide the ability of cold tolerance and adaptation to yeast cells.     

Contrasting demographies and persistence of rare annual plants in highly variable environments

Spatial and temporal variation in critical life history traits differ markedly between two co-occurring, rare and endangered annual plants, Gilia tenuiflora arenaria and Chorizanthe pungens pungens, that have restricted, but overlapping geographic distributions in coastal habitats of central California, USA. Environmental variation was extreme during the 6-year study (1997–2002), with the greatest differences between an intense wet, warm El Niño year (1998), followed by a very dry, cool La Niña (1999). Both species have similar increases in adult survival and seed set with wetter, warmer weather in spring, but they differed in other traits: more Gilia germinated in years with high rainfall and temperature, while more Chorizanthe germinated in dry, cooler years; Gilia abundance increased with the number of years since the previous large El Niño event, while Chorizanthe abundance declined; and Gilia abundance was independent of the previous year’s seed set, while Chorizanthe density was directly related to the previous year’s seed set. The strong negative associations of Chorizanthe abundance with warm, wet weather and with time since the previous El Niño probably reflect the particular sequence of annual weather patterns from 1997 through 2002, especially the extremes in 1998 and 1999. Since it germinates readily in most years under a wide range of winter conditions and does not develop a long-lived seed bank, Chorizanthe seedling abundance reflects recent additions and depletions of its seed bank, rather than prevailing weather, per se. In contrast, Gilia seeds may remain in the seed bank for many years, until relatively rare winter conditions trigger significant germination. These species-specific demographies enhance persistence and coexistence of these species, but the mechanisms differ from each other and from those described for annuals in other highly variable environments.     

Monitoring expression profiles of Arabidopsis genes during cold acclimation and deacclimation using DNA microarrays

A comparative analysis of gene expression profiles during cold acclimation and deacclimation is necessary to elucidate the molecular mechanisms of cold stress responses in higher plants. We analyzed gene expression profiles in the process of cold acclimation and deacclimation (recovery from cold stress) using two microarray systems, the 7K RAFL cDNA microarray and the Agilent 22K oligonucleotide array. By both microarray analyses, we identified 292 genes up-regulated and 320 genes down-regulated during deacclimation, and 445 cold up-regulated genes and 341 cold down-regulated genes during cold acclimation. Many genes up-regulated during deacclimation were found to be down-regulated during cold acclimation, and vice versa. The genes up-regulated during deacclimation were classified into (1) regulatory proteins involved in further regulation of signal transduction and gene expression and (2) functional proteins involved in the recovery process from cold-stress-induced damages and plant growth. We also applied expression profiling studies to identify the key genes involved in the biosynthesis of carbohydrates and amino acids that are known to play important roles in cold acclimation. We compared genes that are regulated during deacclimation with those regulated during rehydration after dehydration to discuss the similarity and difference of each recovery process.Electronic Supplementary Material Supplementary materials are available for this article at