108 research outputs found

    A new species of Reticulitermes Holmgren, 1913 (Isoptera: Rhinotermitidae) from the southeastern United States

    Get PDF
    Reticulitermes nelsonae, a new species of subterranean termite (Isoptera, Rhinotermitidae) is described from Sapelo Island, Georgia, United States of America, with specimens also found in North Carolina and Florida. The adult and soldier castes are described and illustrated to distinguish R. nelsonae from the four described Reticulitermes spp. known to occur in the southeastern United States

    Oxidation of Small Alcohols Using Spinach Photosystem II: Use of a natural catalyst for potential green synthesis

    Get PDF
    Photo system II (PSII), a protein complex found in plants and an integral part of photosynthesis, uses light to oxidize water to oxygen. PSII may also be capable of oxidizing small alcohols. This light driven biotransformation could be an excellent green oxidation method. PSI! was isolated from spinach leaves and its activity verified by quantifying the oxygen produced from water. Methods were developed· to identify alcohols and their oxidized products using gas chromatography. The reaction of 2-propanol and n-propanol with PSI! and light were explored. n-Propanol and PSII were also mixed in the dark with H202 as the potential oxidant. While trace amounts of oxidation products were observed in a few experiments, further investigation of this reaction is necessary to determine whether this method can be used as a viable and quantitative green alternative for the oxidation of alcohols in organic synthesis

    Morphology and taxonomy of the genus Ramazzottius (Eutardigrada; Ramazzottiidae) with the integrative description of Ramazzottius kretschmanni sp. nov

    Get PDF
    The species of the genus Ramazzottius (Ramazzottiidae, Eutardigrada) are among the most common and widespread tardigrade species in the world. Most of the 28 Ramazzottius species have been described only with morphological characters which were most of the time represented only with drawings. The discovery of a new species of this genus in the Black Forest (Germany) provided the opportunity to compare this species with the type specimens of ten Ramazzottius species, to propose the status of species dubia for Ramazzottius edmondabouti, and through new photographs to elucidate the anatomy of animals and eggs (in particular of the head sensory regions, eye spots, buccal tube, ornamentations of the dorsal posterior cuticle, and morphology of egg processes). These thorough observations led to a better understanding of the diversity and evolution, not only of this cosmopolitan genus, but also of other eutardigrade genera. The new species Ramazzottius kretschmanni is described with an integrative approach integrating morphological (light and electron microscopy observations and morphometric data) and molecular (cox1 and ITS2 genes) data. The PTP and ASAP analyses confirmed the validity of the new species from a molecular point of view. The new species is morphologically similar to Ramazzottius oberhaeuseri, but is distinguishable by the smooth cuticle, the presence of a “cheek-like” area on the head, and the size of egg processes as well as different sequences of the molecular markers

    Distribution of Neuropeptide F-Like Immunoreactivity in the Eastern Subterranean Termite, Reticulitermes flavipes

    Get PDF
    The nervous system and gut of worker, soldier and alate castes of the eastern subterranean termite, Reticulitermes flavipes Kollar (Isoptera: Rhinotermitidae) were examined for immunoreactivity to an antiserum to Helicoverpa zea (Boddie) (Leipidoptera: Noctuidae) MP-I (QAARPRF-NH2), a truncated form of neuropeptide F. More than 145 immunostained axons and cell bodies were seen in the brain and all ganglia of the ventral nerve cord. Immunoreactive axons exiting the brain projected anteriorly to the frontal ganglion and posteriorly to the corpora cardiaca and corpora allata. In the stomatogastric nervous system, immunoreactive axons were observed over the surface of the foregut, salivary glands, midgut and rectum. These axons originated in the brain and from 15–25 neurosecretory cells on the foregut. Staining patterns were consistent between castes, with the exception of immunostaining observed in the optic lobes of alates. At least 600 immunoreactive endocrine cells were evenly distributed in the midguts of all castes with higher numbers present in the worker caste. Immunostaining of cells in the nervous system and midgut was blocked by preabsorption of the antiserum with Hez MP-I but not by a peptide having only the RF-NH2 in common. This distribution suggests NPF-like peptides coordinate feeding and digestion in all castes of this termite species

    Coarse woody debris decomposition assessment tool: Model development and sensitivity analysis

    Get PDF
    Coarse woody debris (CWD) is an important component in forests, hosting a variety of organisms that have critical roles in nutrient cycling and carbon (C) storage. We developed a process-based model using literature, field observations, and expert knowledge to assess woody debris decomposition in forests and the movement of wood C into the soil and atmosphere. The sensitivity analysis was conducted against the primary ecological drivers (wood properties and ambient conditions) used as model inputs. The analysis used eighty-nine climate datasets from North America, from tropical (14.2° N) to boreal (65.0° N) zones, with large ranges in annual mean temperature (26.5°C in tropical to -11.8°C in boreal), annual precipitation (6,143 to 181 mm), annual snowfall (0 to 612 kg m-2), and altitude (3 to 2,824 m above mean see level). The sensitivity analysis showed that CWD decomposition was strongly affected by climate, geographical location and altitude, which together regulate the activity of both microbial and invertebrate wood-decomposers. CWD decomposition rate increased with increments in temperature and precipitation, but decreased with increases in latitude and altitude. CWD decomposition was also sensitive to wood size, density, position (standing vs downed), and tree species. The sensitivity analysis showed that fungi are the most important decomposers of woody debris, accounting for over 50% mass loss in nearly all climatic zones in North America. The model includes invertebrate decomposers, focusing mostly on termites, which can have an important role in CWD decomposition in tropical and some subtropical regions. The role of termites in woody debris decomposition varied widely, between 0 and 40%, from temperate areas to tropical regions. Woody debris decomposition rates simulated for eighty-nine locations in North America were within the published range of woody debris decomposition rates for regions in northern hemisphere from 1.6° N to 68.3° N and in Australia

    Coarse Woody Debris Decomposition Assessment Tool: Model Validation and Application

    Get PDF
    Coarse woody debris (CWD) is a significant component of the forest biomass pool; hence a model is warranted to predict CWD decomposition and its role in forest carbon (C) and nutrient cycling under varying management and climatic conditions. A process-based model, CWDDAT (Coarse Woody Debris Decomposition Assessment Tool) was calibrated and validated using data from the FACE (Free Air Carbon Dioxide Enrichment) Wood Decomposition Experiment utilizing pine (Pinus taeda), aspen (Populous tremuloides) and birch (Betula papyrifera) on nine Experimental Forests (EF) covering a range of climate, hydrology, and soil conditions across the continental USA. The model predictions were evaluated against measured FACE log mass loss over 6 years. Four widely applied metrics of model performance demonstrated that the CWDDAT model can accurately predict CWD decomposition. The R2 (squared Pearson’s correlation coefficient) between the simulation and measurement was 0.80 for the model calibration and 0.82 for the model validation (P\u3c0.01). The predicted mean mass loss from all logs was 5.4% lower than the measured mass loss and 1.4% lower than the calculated loss. The model was also used to assess the decomposition of mixed pine-hardwood CWD produced by Hurricane Hugo in 1989 on the Santee Experimental Forest in South Carolina, USA. The simulation reflected rapid CWD decomposition of the forest in this subtropical setting. The predicted dissolved organic carbon (DOC) derived from the CWD decomposition and incorporated into the mineral soil averaged 1.01 g C m-2 y-1 over the 30 years. The main agents for CWD mass loss were fungi (72.0%) and termites (24.5%), the remainder was attributed to a mix of other wood decomposers. These findings demonstrate the applicability of CWDDAT for large-scale assessments of CWD dynamics, and fine-scale considerations regarding the fate of CWD carbon

    Host plant species affects virulence in monarch butterfly parasites

    Full text link
    1.  Studies have considered how intrinsic host and parasite properties determine parasite virulence, but have largely ignored the role of extrinsic ecological factors in its expression. 2.  We studied how parasite genotype and host plant species interact to determine virulence of the protozoan parasite Ophryocystis elektroscirrha ( McLaughlin & Myers 1970 ) in the monarch butterfly Danaus plexippus L. We infected monarch larvae with one of four parasite genotypes and reared them on two milkweed species that differed in their levels of cardenolides: toxic chemicals involved in predator defence. 3.  Parasite infection, replication and virulence were affected strongly by host plant species. While uninfected monarchs lived equally long on both plant species, infected monarchs suffered a greater reduction in their life spans (55% vs. 30%) on the low-cardenolide vs. the high-cardenolide host plant. These life span differences resulted from different levels of parasite replication in monarchs reared on the two plant species. 4.  The virulence rank order of parasite genotypes was unaffected by host plant species, suggesting that host plant species affected parasite genotypes similarly, rather than through complex plant species–parasite genotype interactions. 5.  Our results demonstrate that host ecology importantly affects parasite virulence, with implications for host–parasite dynamics in natural populations. Journal of Animal Ecology (2007) doi: 10.1111/j.1365-2656.2007.01305.xPeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72199/1/j.1365-2656.2007.01305.x.pd
    • …
    corecore