Long-term unsustainable patterns of development rather than recent deforestation caused the emergence of Orthocoronavirinae species

We investigated whether a set of phylogeographical tracked emergent events of Orthocoronavirinae were related to developed, urban and polluted environments worldwide. We explored coronavirus records in response to climate (rainfall parameters), population density, CO₂ emission, Human Developmental Index (HDI) and deforestation. We contrasted environmental characteristics from regions with spillovers or encounters of wild Orthocoronavirinae against adjacent areas having best-preserved conditions. We used all complete sequenced CoVs genomes deposited in NCBI and GISAID databases until January 2021. Except for Deltacoronavirus, concentrated in Hong Kong and in birds, the other three genera were scattered all over the planet, beyond the original distribution of the subfamily, and found in humans, mammals, fishes and birds, wild or domestic. Spillovers and presence in wild animals were only reported in developed/densely populated places. We found significantly more occurrences reported in places with higher HDI, CO₂ emission, or population density, along with more rainfall and more accentuated seasonality. Orthocoronavirinae occurred in areas with significantly higher human populations, CO₂ emissions and deforestation rates than in adjacent locations. Intermediately disturbed ecosystems seemed more vulnerable for Orthocoronavirinae emergence than forested regions in frontiers of deforestation. Sadly, people experiencing poverty in an intensely consumerist society are the most vulnerable.

Climate variability and aridity modulate the role of leaf shelters for arthropods: A global experiment

Current climate change is disrupting biotic interactions and eroding biodiversity worldwide. However, species sensitive to aridity, high temperatures, and climate variability might find shelter in microclimatic refuges, such as leaf rolls built by arthropods. To explore how the importance of leaf shelters for terrestrial arthropods changes with latitude, elevation, and climate, we conducted a distributed experiment comparing arthropods in leaf rolls versus control leaves across 52 sites along an 11,790 km latitudinal gradient. We then probed the impact of short- versus long-term climatic impacts on roll use, by comparing the relative impact of conditions during the experiment versus average, baseline conditions at the site. Leaf shelters supported larger organisms and higher arthropod biomass and species diversity than non-rolled control leaves. However, the magnitude of the leaf rolls' effect differed between long- and short-term climate conditions, metrics (species richness, biomass, and body size), and trophic groups (predators vs. herbivores). The effect of leaf rolls on predator richness was influenced only by baseline climate, increasing in magnitude in regions experiencing increased long-term aridity, regardless of latitude, elevation, and weather during the experiment. This suggests that shelter use by predators may be innate, and thus, driven by natural selection. In contrast, the effect of leaf rolls on predator biomass and predator body size decreased with increasing temperature, and increased with increasing precipitation, respectively, during the experiment. The magnitude of shelter usage by herbivores increased with the abundance of predators and decreased with increasing temperature during the experiment. Taken together, these results highlight that leaf roll use may have both proximal and ultimate causes. Projected increases in climate variability and aridity are, therefore, likely to increase the importance of biotic refugia in mitigating the effects of climate change on species persistence.

Biological Aspects and Movements of Neotropical Fruit-Feeding Butterflies

The patterns of insect movement are the cumulate product of many individual decisions and can be shaped by the way morphology and behaviour interacts with landscape structure and composition. Hence, the ongoing process of habitat fragmentation increases the distance among suitable habitats and changes those in such a way that it may favour some movement behaviour. Our study described some biological traits (sex ratio, age structure and individual permanence in a population), as well as the movements of fruit-feeding butterflies along the horizontal dimension (among habitats: forest interior, natural forest transition - ecotone and anthropogenic forest transition - edge) and the vertical dimension (between canopy and understory). We sampled butterflies monthly over 1 year in the Atlantic rainforest, South-eastern Brazil, following a standardized design using bait traps. We found that sex ratio was male biased for five out of the six more abundant species and the age structure showed an increase in recruitment of new individuals in the dry season followed by a noticeable aging of the populations in the wet season. In general, our results revealed an aggregated spatial distribution, in which few individuals travelled long distances while most individuals were recaptured in the same trap, suggesting that all studied habitats currently provide the necessary conditions for the maintenance of butterfly populations, favouring fewer movements and narrow home ranges for both sexes and species. Conservation of a set of heterogeneous habitats it is especially important for the maintenance of sedentary butterflies and of those that move large distances.

From Spanish Flu to Syndemic COVID-19: long-standing sanitarian vulnerability of Manaus, warnings from the Brazilian rainforest gateway

A second deadlier wave of COVID-19 and the causes of the recent public health collapse of Manaus are compared with the Spanish flu events in that city, and Brazil. Historic sanitarian problems, and its hub position in the Brazilian airway network are combined drivers of deadly events related to COVID-19. These drivers were amplified by misleading governance, highly transmissible variants, and relaxation of social distancing. Several of these same factors may also have contributed to the dramatically severe outbreak of H1N1 in 1918, which caused the death of 10% of the population in seven months. We modelled Manaus parameters for the present pandemic and confirmed that lack of a proper social distancing might select the most transmissible variants. We succeeded to reproduce a first severe wave followed by a second stronger wave. The model also predicted that outbreaks may last for up to five and half years, slowing down gradually before the disease disappear. We validated the model by adjusting it to the Spanish Flu data for the city, and confirmed the pattern experienced by that time, of a first stronger wave in October-November 1918, followed by a second less intense wave in February-March 1919.

Wearable Edge AI Applications for Ecological Environments

Ecological environments research helps to assess the impacts on forests and managing forests. The usage of novel software and hardware technologies enforces the solution of tasks related to this problem. In addition, the lack of connectivity for large data throughput raises the demand for edge-computing-based solutions towards this goal. Therefore, in this work, we evaluate the opportunity of using a Wearable edge AI concept in a forest environment. For this matter, we propose a new approach to the hardware/software co-design process. We also address the possibility of creating wearable edge AI, where the wireless personal and body area networks are platforms for building applications using edge AI. Finally, we evaluate a case study to test the possibility of performing an edge AI task in a wearable-based environment. Thus, in this work, we evaluate the system to achieve the desired task, the hardware resource and performance, and the network latency associated with each part of the process. Through this work, we validated both the design pattern review and case study. In the case study, the developed algorithms could classify diseased leaves with a circa 90% accuracy with the proposed technique in the field. This results can be reviewed in the laboratory with more modern models that reached up to 96% global accuracy. The system could also perform the desired tasks with a quality factor of 0.95, considering the usage of three devices. Finally, it detected a disease epicenter with an offset of circa 0.5 m in a 6 m × 6 m × 12 m space. These results enforce the usage of the proposed methods in the targeted environment and the proposed changes in the co-design pattern.

Anadenanthera colubrina (Fabaceae) logs in the Atlantic Forest biome: first host plant for Thoracibidion lineatocolle (Col.: Cerambycidae) and a new host for Temnopis megacephala (Col.: Cerambycidae)

Wood-boring beetles develop in live trees and dead wood, performing ecological services such as decomposition and regulation of forest resources. Species of the Cerambycidae family, widely distributed in the world, bore into the trunks of trees and dead wood in native and cultivated areas. The objective is to report the first host plant for Thoracibidion lineatocolle (Thomson, 1865) (Coleoptera: Cerambycidae) and a new host plant for Temnopis megacephala (Germar, 1824) (Coleoptera: Cerambycidae) in the Brazilian Atlantic Forest biome. Three logs, with one-meter-long by 20 cm in diameter, were cut from the trunk of a healthy Anadenanthera colubrina (Fabaceae) tree in October 2013 and tied in the understory at 1.5m high in the Rio Doce State Park, Minas Gerais State, Brazil. The logs, exposed in the forest, were each removed after 40, 80 and 120 days and stored individually in a cardboard box in the "Laboratório de Campo do Projeto de Ecologia de Longa Duração (PELD-CNPq)" in the Rio Doce State Park. A total of 94 individuals of T. lineatocolle and 228 of T. megacephala emerged from the A. colubrina logs. This is the first report of a host plant for T. lineatocolle and a new host plant for T. megacephala.

Field Research Cooperative Wearable Systems: Challenges in Requirements, Design and Validation

The widespread availability of wearable devices is evolving them into cooperative systems. Communication and distribution aspects such as the Internet of Things, Wireless Body Area Networks, and Local Wireless Networks provide the means to develop multi-device platforms. Nevertheless, the field research environment presents a specific feature set, which increases the difficulty in the adoption of this technology. In this text, we review the main aspects of Field Research Gears and Wearable Devices. This review is made aiming to understand how to create cooperative systems based on wearable devices directed to the Field Research Context. For a better understanding, we developed a case study in which we propose a cooperative system architecture and provide validation aspects. For this matter, we provide an overview of a previous device architecture and study an integration proposal.

Taxonomic and functional diversity of insect herbivore assemblages associated with the canopy-dominant trees of the Azorean native forest

Oceanic islands have been providing important insights on the structuring of ecological communities and, under the context of the present biodiversity crisis, they are paramount to assess the effects of biological invasions on community assembly. In this study we compare the taxonomic and functional diversity of insect herbivore assemblages associated with the dominant tree species of Azorean native forests and investigate the ecological processes that may have originated current patterns of plant-herbivore associations. Five dominant trees-Erica azorica, Ilex perado subsp. azorica, Juniperus brevifolia, Laurus azorica and Vaccinium cylindraceum-were sampled in the remnants of the native forest of Terceira Island (Azores) using a standardised methodology. The taxonomic and functional diversity of insect herbivore assemblages was assessed using complementary metrics and beta diversity partitioning analysis (species replacement and richness differences) aiming to evaluate the variation in insect herbivore assemblages within and between the study plant species. Sixty two insect species, mostly bugs (Hemiptera) and caterpillars (Lepidoptera), were found in the five study plants with indigenous (endemic and native non-endemic) insects occurring with higher species richness and abundance than introduced ones. Species replacement was the most important component of insect herbivore taxonomic beta diversity while differences in trait richness played a major role on functional beta diversity. The endemic E. azorica stands out from the other study plants by having associated a very distinct insect herbivore assemblage with a particular set of functional attributes, mainly composed by large bodied and long shaped species that feed by chewing. Despite the progressive biotic homogenization witnessed in the Azores during the last few decades, several strong associations between the endemic trees and their indigenous insect herbivores remain.

Ant species richness and interactions in canopies of two distinct successional stages in a tropical dry forest

Canopy ecology is a fast-growing field, but still a scientific frontier in many ecological aspects. For instance, the hypothesis that tree traits shape patterns in ant-plant interactions lacks data, notably for tropical canopies in different successional stages. In this study, we investigated canopy traits, such as tree height, the presence of extrafloral nectaries (EFNs), connectivity among tree crowns, and successional stage, structure ant-tree interactions in a tropical dry forest (TDF), examining whether these are the determinant factors for ant species richness. We collected ants on trees in early and late successional stages over 2 years, in rainy and dry seasons. In the late successional stage, ant species richness was greater in the taller trees; in the early successional stage, the smallest trees had a greater ant species richness than the taller trees. The EFNs and connectivity among treetops had no effect on ant species richness. We obtained a tree-ant network of the early successional stage, involving 786 interactions among 57 ant species and 75 trees; in the late successional stage, the network had 914 interactions among 60 ant species and 75 trees. There were 27 species of trees in our study, 11 of which (40.7% of all individual trees) had EFNs. The ant-plant interactions were not randomly distributed, suggesting that various biotic factors structured the ant assemblies. This study presents new insights into ant-tree interactions, showing that both tree height and successional stage influence the occurrence of many species of ants in tree canopies of tropical dry forests.

Equal but different: Natural ecotones are dissimilar to anthropic edges

Increasing deforestation worldwide has expanded the interfaces between fragmented forests and non-forest habitats. Human-made edges are very different from the original forest cover, with different microclimatic conditions. Conversely, the natural transitions (i.e., ecotones) are distinct from human-made forest edges. The human-made forest edges are usually sharp associated with disturbances, with abrupt changes in temperature, humidity, luminosity and wind incidence towards the forest interior. However, the natural forest-lake ecotones, even when abrupt, are composed of a complex vegetal physiognomy, with canopy structures close to the ground level and a composition of herbaceous and arboreal species well adapted to this transition range. In the present study, fruit-feeding butterflies were used as models to investigate whether faunal assemblages in natural ecotones are more similar to the forest interior than to the anthropic edges. Butterflies were sampled monthly over one year in the Rio Doce State Park, Southeastern Brazil, following a standardized design using a total of 90 bait traps, in three different forest habitats (forest interior, forest ecotone and anthropic edges), in both canopy and understory. A total of 11,594 individuals from 98 butterfly species were collected (3,151 individuals from 79 species in the forest interior, 4,321 individuals from 87 species in the ecotone and 4,122 individuals from 83 species in the edge). The results indicated that the butterfly richness and diversity were higher in transition areas (ecotones and edges). The ecotone included a combination of butterfly species from the forest interior and from anthropic edges. However, species composition and dominance in the ecotone were similar to the forest interior in both vertical strata. These results suggest that human made forest edges are quite distinct from ecotones. Moreover, ecotones represent unique habitats accommodating species adapted to distinct ecological conditions, while anthropic edges accommodate only opportunistic species from open areas or upper canopies.

Plant Growth Promoting Bacteria Associated with Langsdorffia hypogaea-Rhizosphere-Host Biological Interface: A Neglected Model of Bacterial Prospection

Soil is a habitat where plant roots and microorganisms interact. In the region of the Brazilian Iron Quadrangle (IQ), studies involving the interaction between microbiota and plants have been neglected. Even more neglected are the studies involving the holoparasite plant Langsdorffia hypogaea Mart. (Balanophoraceae). The geomorphological peculiarities of IQ soil, rich in iron ore, as well as the model of interaction between L. hypogaea, its hosts and the soil provide a unique niche that acts as selective pressure to the evolution of plant growth-promoting bacteria (PGPB). The aim of this study was to prospect the bacterial microbiota of holoparasitic plant L. hypogaea, its plant host and corresponding rhizosphere of IQ soil, and to analyze the potential of these isolates as PGPB. We obtained samples of 11 individuals of L. hypogaea containing fragments of host and rhizosphere remnants, resulting in 81 isolates associated with Firmicutes and Proteobacteria phyla. The ability to produce siderophores, hydrocyanic acid (HCN), indole-3-acetic acid (IAA), nitrogen (N₂) fixation, hydrolytic enzymes secretion and inhibition of enteropathogens, and phytopathogens were evaluated. Of the total isolates, 62, 86, and 93% produced, respectively, siderophores, IAA, and were able to fix N₂. In addition, 27 and 20% of isolates inhibited the growth of enteropathogens and phytopathogens, respectively, and 58% were able to produce at least one hydrolytic activity investigated. The high number of isolates that produce siderophores and indole-3-acetic acid suggests that this microbiota may be important for adaptation of plants to IQ. The results demonstrate for the first time the biological importance of Brazilian IQ species as reservoirs of specific microbiotas that might be used as PGPB on agricultural land or antropized soils that needs to be reforested.

Analysis of iron superoxide dismutase-encoding DNA vaccine on the evolution of the Leishmania amazonensis experimental infection

The present work aimed to evaluate the immunogenicity of Leishmania amazonensis iron superoxide dismutase (SOD)-encoding DNA experimental vaccine and the protective properties of this DNA vaccine during infection. The SOD gene was subcloned into the pVAX1 plasmid, and it was used to immunize BALB/c mice. Twenty-one days after the last immunization, mice were sacrificed (immunogenicity studies) or subcutaneously challenged with L. amazonensis (studies of protection), and alterations in cellular and humoral immune responses were evaluated, as well as the course of infection. Mice only immunized with pVAX1-SOD presented increased frequencies of CD4(+) IFN-γ(+), CD8(+)IFN-γ(+) and CD8(+)IL-4(+) lymphocytes; moreover, high levels of IgG2a were detected. After challenge, mice that were immunized with pVAX1-SOD had increased frequencies of the CD4(+)IL-4(+), CD8(+)IFN-γ(+) and CD8(+)IL-4(+) T lymphocytes. In addition, the lymph node cells produced high amounts of IFN-γ and IL-4 cytokines. Increased IgG2a was also detected. The pattern of immunity induced by pVAX1-SOD partially protected the BALB/c mice from a challenge with L. amazonensis, as the animals presented reduced parasitism and lesion size when compared to controls. Taken together, these results indicate that leishmanial SOD modulates the lymphocyte response, and that the elevation in IFN-γ possibly accounted for the decreased skin parasitism observed in immunized animals.

Arthropod Distribution in a Tropical Rainforest: Tackling a Four Dimensional Puzzle

Quantifying the spatio-temporal distribution of arthropods in tropical rainforests represents a first step towards scrutinizing the global distribution of biodiversity on Earth. To date most studies have focused on narrow taxonomic groups or lack a design that allows partitioning of the components of diversity. Here, we consider an exceptionally large dataset (113,952 individuals representing 5,858 species), obtained from the San Lorenzo forest in Panama, where the phylogenetic breadth of arthropod taxa was surveyed using 14 protocols targeting the soil, litter, understory, lower and upper canopy habitats, replicated across seasons in 2003 and 2004. This dataset is used to explore the relative influence of horizontal, vertical and seasonal drivers of arthropod distribution in this forest. We considered arthropod abundance, observed and estimated species richness, additive decomposition of species richness, multiplicative partitioning of species diversity, variation in species composition, species turnover and guild structure as components of diversity. At the scale of our study (2 km of distance, 40 m in height and 400 days), the effects related to the vertical and seasonal dimensions were most important. Most adult arthropods were collected from the soil/litter or the upper canopy and species richness was highest in the canopy. We compared the distribution of arthropods and trees within our study system. Effects related to the seasonal dimension were stronger for arthropods than for trees. We conclude that: (1) models of beta diversity developed for tropical trees are unlikely to be applicable to tropical arthropods; (2) it is imperative that estimates of global biodiversity derived from mass collecting of arthropods in tropical rainforests embrace the strong vertical and seasonal partitioning observed here; and (3) given the high species turnover observed between seasons, global climate change may have severe consequences for rainforest arthropods.

Evidences that human disturbance simplify the ant fauna associated a Stachytarpheta glabra Cham. (Verbenaceae) compromising the benefits of ant-plant mutualism

Interaction among species, like ants and plants through extrafloral nectaries (EFNs), are important components of ecological communities' evolution. However, the effect of human disturbance on such specific interactions and its ecological consequences is poorly understood. This study evaluated the outcomes of mutualism between ants and the EFN-bearing plant Stachytarpheta glabra under anthropogenic disturbance. We compared the arthropod fauna composition between two groups of twenty plant individuals, one in an area disturbed by human activities and one in a preserved area. We also check the plant investment in herbivory defense and the consequential leaf damage by herbivore. Our results indicate that such disturbances cause simplification of the associated fauna and lack of proper ant mutualist. This led to four times more herbivory on plants of disturbed areas, despite the equal amount of EFN and ant visitors and low abundance of herbivores. The high pressure of herbivory may difficult the re-establishment of S. glabra, an important pioneer species in ferruginous fields, therefore it may affect resilience of this fragile ecological community.

Are ant assemblages of Brazilian veredas characterised by location or habitat type?

Wetland areas in the Brazilian Cerrado, known as "veredas", represent ecosystems formed on sandy soils with high concentrations of peat, and are responsible for the recharge of aquiferous reservoirs. They are currently under threat by various human activities, most notably the clearing of vegetation for Eucalyptus plantations. Despite their ecological importance and high conservation value, little is known about the actual effects of human disturbance on the animal community. To assess how habitat within different veredas, and plantations surrounding them affect ant assemblages, we selected four independent vereda locations, two being impacted by Eucalyptus monoculture (one younger and one mature plantation) and two controls, where the wetland was surrounded by cerrado vegetation. Ant sampling was conducted in May 2010 (dry season) using three complementary methods, namely baits, pitfall traps, and hand collection, in the wetland and in the surrounding habitats. A total of 7,575 ants were sampled, belonging to seven subfamilies, 32 genera and 124 species. Ant species richness and abundance did not differ between vereda locations, but did between the habitats. When impacted by the monoculture, ant species richness and abundance decreased in wetlands, but were less affected in the cerrado habitat. Ant species composition differed between the three habitats and between vereda locations. Eucalyptus plantations had an ant species composition defined by high dominance of Pheidole sp. and Solenopsis invicta, while natural habitats were defined by Camponotus and Crematogaster species. Atta sexdens was strictly confined to native habitats of non-impacted "veredas". Eucalyptus monocultures require high quantities of water in the early stages, which may have caused a decrease in groundwater level in the wetland, allowing hypogeic ants such as Labidus praedator to colonise this habitat.

Contrasting effects of sampling scale on insect herbivores distribution in response to canopy structure

Species diversity of insect herbivores associated to canopy may vary local and geographically responding to distinct factors at different spatial scales. The aim of this study was to investigate how forest canopy structure affects insect herbivore species richness and abundance depending on feeding guilds' specificities. We tested the hypothesis that habitat structure affects insect herbivore species richness and abundance differently to sap-sucking and chewing herbivore guilds. Two spatial scales were evaluated: inside tree crowns (fine spatial cale) and canopy regions (coarse spatial scale). In three sampling sites we measured 120 tree crowns, grouped n five points with four contiguous tree crowns. Insects were sampled by beating method from each crown and data were summed up for analyzing each canopy region. In crowns (fine spatial scale) we measured habitat tructure: trunk circumference, tree height, canopy depth, number of ramifications and maximum ramification level. In each point, defined as a canopy region (coarse spatial scale), we measured habitat structure using a vertical cylindrical transect: tree species richness, leaf area, sum of strata heights and maximum canopy height. A principal component analysis based on the measured variables for each spatial scale was run to estimate habitat structure parameters. To test the effects of habitat structure upon herbivores, different general linear models were adjusted using the first two principal components as explanatory variables. Sap-sucking insect species richness and all herbivore abundances increased with size of crown at fine spatial scale. On the other hand, chewer species richness and abundance increased with resource quantity at coarse scale. Feeding specialization, resources availability, and agility are discussed as ecological causes of the found pattern.

Arthropod diversity in a tropical forest

Most eukaryotic organisms are arthropods. Yet, their diversity in rich terrestrial ecosystems is still unknown. Here we produce tangible estimates of the total species richness of arthropods in a tropical rainforest. Using a comprehensive range of structured protocols, we sampled the phylogenetic breadth of arthropod taxa from the soil to the forest canopy in the San Lorenzo forest, Panama. We collected 6144 arthropod species from 0.48 hectare and extrapolated total species richness to larger areas on the basis of competing models. The whole 6000-hectare forest reserve most likely sustains 25,000 arthropod species. Notably, just 1 hectare of rainforest yields >60% of the arthropod biodiversity held in the wider landscape. Models based on plant diversity fitted the accumulated species richness of both herbivore and nonherbivore taxa exceptionally well. This lends credence to global estimates of arthropod biodiversity developed from plant models.

[The bamboo Merostachys fischeriana (Bambusoideae: Bambuseae) as a canopy habitat for ants of Neotropical Montane Forest]

Although Merostachys fischeriana is very abundant in the Brazilian Atlantic Rainforest, little attention has been paid to the biological interactions with other animals. The present study describes some of the interactions between ants and this bamboo species. The experiment was carried out in a fragment of a montane tropical forest in the Parque Estadual do Itacolomi, near Ouro Preto, MG, Brazil. Thirty culms of bamboo were randomly collected. The ants were obtained by direct collection from nodes and internodes. Morphometric variables of the bamboo were recorded for characterization of potential ant habitat. Merostachys fischeriana grows in rosettes as a thin bamboo (average = 1,0 cm; se = 0,27; n = 20) and is tall enough to reach the upper canopy of this low forest (average = 9,1 m; se = 2,72; n = 20). Fifteen ant species were sampled. Brachymyrmex heeri Forel was the most abundant in the nodes, while Camponotus crassus Mayr (Hymenoptera: Formicidae) was the most abundant in the internodes. The composition of the species that inhabit the internodes was different from the composition in the node (Q-test: Q = 3,76; P = 0,05). The level of occupation was defined by the number of holes (F = 10,33; P < 0,01), the number of internodes in the canopy (F = 6,84; P = 0,01) and the length of the culm (F = 7,52; P = 0,01). The plant's morphology allowed the occurrence of additional species of ants in the canopy and influenced the composition of the entire ant assemblage.

Environment heterogeneity and seasonal effects in ground-dwelling ant (Hymenoptera: Formicidae) assemblages in the Parque Estadual do Rio Doce, MG, Brazil

This work aimed to explore the response of ant species assemblage to contrasting types of forests in a semideciduous stationary rainforest, in the Parque Estadual do Rio Doce, South Eastern Brazil. We compared antropomorphic borders of this park and natural ecotones, such as lake margins continuous with forests, as well as preserved forests far from ecotones. We investigated whether ground-dwelling ant species richness, abundance and composition would change according to forest types and ecotones. We expected greater species richness in interior tall forest, compared with low forest or ecotone habitats. In addition, we tested the effect of climate seasonality on ant assemblages found in each studied vegetation type. Each forest type was surveyed based on a minimum transect sampling unit of 150 m long summing up 30 pit-falls per unit. Two sampling events, one in dry season (September of 2001) and another in the rainy season (January of 2002) were performed. For both seasons, tall forest presented greater total number of ant species, however lower mean ant species and abundance per trap than other forest types, thus corroborating the prediction that ecotones might present high alpha diversity. Mean species richness and abundance did not differ between interior low forest and lake edge, or between these habitats and reserve border. In general, species composition were not clearly defined by forest types. Results here found suggest that species loss or community dominance by generalist species, eventually due to deforestation, is probably a much greater problem than previously thought. However, to understand patterns of insect species diversity and distribution in tropical ecosystem should be taken in account much more comprehensive, spatially explicit sampling designs.

Heat Stress Attenuates Ventilator-induced Lung Dysfunction in anEx vivoRat Lung Model

Our laboratory has previously shown decreased mortality rates and the attenuation of lung injury in rats exposed to heat stress (H) 18 h prior to induction of sepsis. In the present study, we examined the hypothesis that heat stress would protect lungs against ventilator-induced lung injury. Male Sprague-Dawley rats were anesthetized and randomly allocated to receive either sham treatment or exposure to heat (rectal temperature 41 degrees C, for 15 min). The lungs were harvested 18 h later, a pressure-volume (P- V) curve was constructed, and the lungs were either lavaged for cytokine and surfactant analyses (preventilation data) or were mechanically ventilated with VT 40 ml/kg in a warmed, humidified chamber. After 2 h of mechanical ventilation, another P-V curve was constructed and the lungs were lavaged for cytokine and surfactant analyses (postventilation data). Mechanical ventilation in control lungs produced a 47% decrease in chord compliance, an increase in lung lavage levels of tumor necrosis factor (TNF)-alpha (722 +/- 306 pg/ml), interleukin (IL)-1beta (902 +/- 322 pg/ml), and macrophage inflammatory protein-2 (MIP-2) (363 +/- 104 pg/ml) as compared with low levels of cytokines detected in preventilation data, and no change in percentage of surfactant large aggregates (LA). In contrast, in mechanically ventilated lungs from animals that were exposed to heat stress we observed a smaller decrease in chord compliance (17%), a significant attenuation in cytokine levels (TNF-alpha 233 +/- 119 pg/ml; IL-1beta 124 +/- 53 pg/ml; MIP-2 73 +/- 52 pg/ml; p < 0.05) and a significant increase in percentage LA compared with control animals. We conclude that exposing animals to heat stress confers protection against the effects of an injurious form of mechanical ventilation, by a mechanism that may involve attenuation of cytokines and preservation of some surfactant properties.

Direct and indirect effects of climate change on St John's wort, Hypericum perforatum L. (Hypericaceae)

We report results from a continuing, long-term field experiment addressing biotic responses to climatic change in grasslands. We focus on effects of summer precipitation (enhanced rainfall, drought, control) and winter ground temperatures (warming, control) on growth, reproduction and herbivory in St John's wort, Hypericum perforatum L. Both winter warming and summer rainfall regimes modified performance and interactions of H. perforatum, particularly those with herbivorous insects. Winter warming had positive effects, with earlier initiation of plant growth and reduced damage by gall-forming and sucking insects in spring, but also had strong negative effects on plant height, flowering, and reproduction. Summer drought reduced reproductive success, but even severe drought did not affect plant growth or flowering success directly. Rather, summer drought acted indirectly by modifying interactions with herbivorous insects via increased vulnerability of the plants to herbivory on flowers and capsules. Overall, the effects of summer precipitation were expressed mainly through interactions that altered the responses to increased winter temperatures, particularly as summer drought increased. The field site, in Oxfordshire, UK, is near the northern limit of distribution of the species, and the experiment tested probable responses of H. perforatum as climates shift towards those more typical of the current center of the distribution of the species. However, if climates do change according to the projected scenarios, then H. perforatum is unlikely to fare well near its northern boundary. Increased winter temperatures, particularly if accompanied by increased summer drought, will probably render this species even less abundant in England than at present.

Heat stress increases survival rates in lipopolysaccharide-stimulated rats

OBJECTIVE

To examine the hypothesis that heat stress applied after the administration of bacterial endotoxin is protective.

DESIGN

Prospective, randomized, laboratory study.

SETTING

University research laboratory.

SUBJECTS

One hundred eleven adult male Sprague-Dawley rats (weight range 250 to 400 g).

INTERVENTIONS

Production of endotoxemia by the administration of a bacterial endotoxin and exposure to heat stress by heating animals in a neonatal incubator until their rectal temperatures reached 105.8 degrees F (41 degrees C).

MEASUREMENTS AND MAIN RESULTS

The rats (n = 111) were anesthetized and were injected with 15 mg/kg of Escherichia coli endotoxin (lipopolysaccharide, LPS) intravenously to produce septic shock. Immediately thereafter, a set of 50 rats were randomly assigned to one of two treatment groups: a) LPS-treated (control); or b) LPS-treated and heated to 105.8 degrees F (41 degrees C). The animals were then observed for the development of fever, and survival rates were monitored for 72 hrs. In another set of 40 animals, the same experimental protocol was used to determine plasma cytokine concentrations in heated and nonheated groups. Blood samples were obtained at 0, 2, 4, or 6 hrs after LPS injection for tumor necrosis factor-alpha and interleukin (IL)-1 beta detection. In a third set of animals, the same experimental protocol was applied to nine animals for the detection of heat-shock proteins of 72-kilodalton molecular weight. LPS injection in the control group did not produce fever. Heat stress increased the abundance of heat-shock proteins of 72-kilodalton molecular weight in the rats' lungs (analysis of variance, p = .016). Twelve hours after the initiation of sepsis, the survival rates of the control group injected with LPS alone and the group heated to 105.8 degrees F (41 degrees C) were 48% and 80%, respectively (p = .039). The peak plasma IL-1 beta concentrations occurring at 2 hrs after LPS injection were significantly reduced in rats heated to 105.8 degrees F (41 degrees C) when compared with nonheated rats (p = .003).

CONCLUSION

We conclude that heat stress applied after the initiation of endotoxemia can provide protection against an otherwise lethal stimulus and that the mechanism of protection may be related to the attenuation of plasma IL-1 beta concentrations.

Injurious ventilatory strategies increase cytokines and c-fos m-RNA expression in an isolated rat lung model

We examined the effect of ventilation strategy on lung inflammatory mediators in the presence and absence of a preexisting inflammatory stimulus. 55 Sprague-Dawley rats were randomized to either intravenous saline or lipopolysaccharide (LPS). After 50 min of spontaneous respiration, the lungs were excised and randomized to 2 h of ventilation with one of four strategies: (a) control (C), tidal volume (Vt) = 7 cc/kg, positive end expiratory pressure (PEEP) = 3 cm H2O; (b) moderate volume, high PEEP (MVHP), Vt = 15 cc/kg; PEEP = 10 cm H2O; (c) moderate volume, zero PEEP (MVZP), Vt = 15 cc/kg, PEEP = 0; or (d) high volume, zero PEEP (HVZP), Vt = 40 cc/kg, PEEP = 0. Ventilation with zero PEEP (MVZP, HVZP) resulted in significant reductions in lung compliance. Lung lavage levels of TNFalpha, IL-1beta, IL-6, IL-10, MIP-2, and IFNgamma were measured by ELISA. Zero PEEP in combination with high volume ventilation (HVZP) had a synergistic effect on cytokine levels (e.g., 56-fold increase of TNFalpha versus controls). Identical end inspiratory lung distention with PEEP (MVHP) resulted in only a three-fold increase in TNFalpha, whereas MVZP produced a six-fold increase in lavage TNFalpha. Northern blot analysis revealed a similar pattern (C, MVHP < MVZP < HVZP) for induction of c-fos mRNA. These data support the concept that mechanical ventilation can have a significant influence on the inflammatory/anti-inflammatory milieu of the lung, and thus may play a role in initiating or propagating a local, and possibly systemic inflammatory response.

Effects of the stress response in septic rats and LPS-stimulated alveolar macrophages: evidence for TNF-alpha posttranslational regulation

We have previously demonstrated that induction of the stress response, by heat stress or sodium arsenite, administered 18 h before initiation of sepsis in rats, significantly decreased mortality and lung injury. As a possible mechanism underlying this effect, we hypothesized that the induction of the stress response, prior to bacterial endotoxin (lipopolysaccharide, LPS) stimulation, would cause a decrease in synthesis and/or release of tumor necrosis factor-alpha (TNF-alpha), making the animals more resistant to sepsis. Rats exposed to Salmonella typhosa LPS demonstrated a rise in plasma TNF-alpha. In contrast, rats exposed to heat stress or to sodium arsenite 18 h prior to LPS had significantly lower levels of plasma TNF-alpha. To examine the mechanisms by which the stress response mediates this decrease, we studied cultured alveolar macrophages. Similar to in vivo studies, TNF released into supernatants of alveolar macrophages treated with LPS was significantly higher than from cells exposed to the stress response prior to LPS. The decrease in TNF-alpha protein release was not accompanied by a similar decrease in TNF-alpha mRNA levels or by a decrease in cell-associated TNF-alpha, suggesting possible posttranslational regulation of TNF-alpha. To determine whether the decrease in TNF-alpha release was due to binding and sequestration by heat shock proteins (HSP), TNF-alpha was purified by immunoprecipitation. Under these conditions, TNF-alpha and HSP72kDa coprecipitated from cells that had received stress treatment prior to LPS. These data implicate HSP in posttranslational control of TNF-alpha release in LPS-stimulated alveolar macrophages exposed to the stress response.

Heat shock-sensitive expression of calreticulin. In vitro and in vivo up-regulation

Calreticulin (CRT) is an ubiquitous, highly conserved, Ca(2+)-binding protein of the sarcoplasmic and endoplasmic reticulum. The precise function(s) of CRT is unknown. However, based on sequence analyses and observations that it may bind to steroid receptors and integrins and store Ca2+ within the cell, it has been postulated to play a "housekeeping" role. To determine whether the level of expression of CRT is affected by stress, we examined the heat shock response of CRT from a variety of cultured cells, including vascular endothelial, lung epithelial, and lung fibroblasts. Following exposure of the cells to 42 degrees C, CRT mRNA transiently accumulated 2.5-4.2-fold at 1-6 h. Nuclear run-on studies and mRNA stability experiments confirmed that the predominant mechanism of augmentation was transcriptional. Chloramphenicol acetyltransferase assays further indicated that the promoter region, containing a putative heat shock element between -172 and -158 of the human CRT gene, is heat shock-sensitive. Finally, we demonstrated the in vivo significance of these findings by exposing rats to hyperthermia. This resulted in accumulation of CRT mRNA and an augmentation of CRT protein in lung tissue. We hypothesize that this stress-induced up-regulation of CRT contributes to the mechanism(s) by which the vascular endothelium and lung tissue, and possibly other organ systems, maintain homeostasis when exposed to a variety of pathophysiological conditions.

Induction of the stress response to prevent organ injury

Septic shock, multiorgan dysfunction, and the acute respiratory distress syndrome are major contributors to morbidity and mortality in the ICU setting. Animal studies have shown that these forms of injury can be attenuated or prevented if a phenomenon, called the stress response, is activated. The stress response, characterized by a transient downregulation of most cellular products and by the upregulation of the heat-shock proteins (HSPs), has been shown to provide protection to cells and experimental animals if triggered prior to an otherwise lethal injury. The mechanisms by which the stress response is protective are not known with certainty, but HSPs appear to play an important role. HSPs are constitutively present in all cells studied to date and can also be induced by artificial fever and by nonthermal means. They act as molecular chaperones, interacting transiently with newly synthesized proteins and proteins experiencing difficulty in proper folding. HSPs also escort and help proteins to cross membranes. This chaperone function is essential for cellular protection since it provides a mechanism by which defective polypeptides may be directed to lisosomes for degradation. This article summarizes the current literature on the effects of the stress response in protecting cells and animals from lethal forms of systemic and organ damage.

Increased nitric oxide in exhaled gas as an early marker of lung inflammation in a model of sepsis

Nitric Oxide (NO) has been implicated in the pathologic vasodilation of sepsis. Because NO can be measured in the exhaled gas of animals and humans, we hypothesized that increases in exhaled NO would occur in a septic model. Using a blinded design, 10 male Sprague-Dawley rats (300 to 400 g) were anesthetized, paralyzed, tracheotomized, and randomized (5/group) to receive an intravenous injection of either lipopolysaccharide (LPS) (Salmonella typhosa, 20 mg/kg) or placebo (equal volume of saline). Thereafter, exhaled gas was collected and measurements of NO concentration were made using chemiluminescence every 20 min for 300 min during ventilation (RR 40 breaths/min, VT 3 ml; PEEP 0, FIO2 0.21). Another group of 10 animals (5 LPS; 5 control) were treated in the same fashion and then killed at 240 min and an arterial blood sample obtained for blood gas and TNF alpha determinations. Pressure volume (PV) curves were constructed and lungs removed, preserved, and submitted for histologic evaluation. LPS-treated rats had lower mean arterial pressures than the control group, p < 0.0001. No significant differences in static lung compliance and PV curves were found in the two groups. TNF alpha levels were greater in the LPS group (1.40 +/- 0.24 ng/ml) versus control group (0.09 +/- 0.04 ng/ml), p < 0.001. By contrast to the control group, exhaled NO concentration rose in all LPS-treated rats at approximately 100 min and at about 160 min reached a plateau that was 6 times greater than control levels (p < 0.0001). There was greater interstitial, airspace, and total lung injury in the LPS group (p = 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Sodium arsenite induces heat shock protein-72 kilodalton expression in the lungs and protects rats against sepsis

OBJECTIVE

To examine the hypothesis that induction of heat shock proteins by a nonthermal mechanism would confer protection against experimental sepsis.

DESIGN

Prospective, blind, randomized, laboratory study.

SETTING

University research laboratory.

SUBJECTS

Sixty-two adult male Sprague-Dawley rats (weight range 250 to 350 g).

INTERVENTIONS

Administration of sodium arsenite or saline in an animal model of sepsis by cecal ligation and perforation.

MEASUREMENTS AND MAIN RESULTS

Sixty-two rats were randomly divided into two groups: group 1 received sodium arsenite (6 mg/kg iv) and group 2 received saline injection, in a blinded fashion. Eighteen hours after receiving sodium arsenite or saline, cecal ligation and perforation were performed and the animals were monitored for mortality for 96 hrs. Sodium arsenite injection, in the absence of an increase in body temperature, induced heat shock protein of 72-kilodalton molecular weight expression in the lung, which was detected 2 hrs after injection, peaked between 9 and 24 hrs, and returned to baseline by 48 hrs. Prior administration of sodium arsenite conferred significant protection against cecal ligation and perforation-induced mortality at 18 hrs (p = .002) and 24 hrs (p v .026) after cecal ligation and perforation, and correlated with expression of heat shock proteins in the lungs. However, at 48 and 96 hrs, when heat shock protein expression returned to basal values, the mortality rates of both groups were indistinguishable.

CONCLUSIONS

We conclude that in vivo injection of sodium arsenite induces expression of HSP-72 in the lungs, and confers transient protection against experimental sepsis during the period that heat shock proteins are also expressed.

Induction of the heat shock response reduces mortality rate and organ damage in a sepsis-induced acute lung injury model

OBJECTIVE

To test the hypothesis that induction of heat shock proteins before the onset of sepsis could prevent or reduce organ injury and death in a rat model of intra-abdominal sepsis and sepsis-induced acute lung injury produced by cecal ligation and perforation.

DESIGN

Prospective, blind, randomized, controlled trial.

SETTING

University research laboratory.

SUBJECTS

One-hundred forty-two adult Sprague-Dawley rats (weight range 200 to 300 g).

INTERVENTIONS

Production of intra-abdominal sepsis and exposure to heat stress. Animals were randomly divided into four groups: heated and septic, heated and sham-septic, unheated and septic, and unheated and sham-septic.

MEASUREMENTS AND MAIN RESULTS

We evaluated the mortality rate and pathologic changes in lung, heart, and liver at 18 hrs after cecal perforation, at 24 hrs after removal of the cecum, and at 7 days after perforation. Heated animals exhibited a maximum increase in heat shock protein of 72 kilodalton molecular weight protein concentrations in the lungs and heart 6 to 24 hrs after the hyperthermic stress. By 18 hrs after perforation, 25% of the septic, unheated animals had died whereas none of the septic heated animals had died (p < .005). Septic, heated animals showed a marked decrease in 7-day mortality rate (21%) compared with septic unheated animals (69%) (p < .01). Furthermore, septic heated animals showed less histologic evidence of lung and liver damage than septic unheated animals.

CONCLUSIONS

These data suggest that thermal pretreatment, associated with the synthesis of heat shock proteins, reduces organ damage and enhances animal survival in experimental sepsis-induced acute lung injury. Although the mechanisms by which heat shock proteins exert a protective effect are not well understood, these data raise interesting questions regarding the importance of fever in the protection of the whole organism during bacterial infection.