Energetic cost of bot fly parasitism in free-ranging eastern chipmunks

The energy and nutrient demands of parasites on their hosts are frequently invoked as an explanation for negative impacts of parasitism on host survival and reproductive success. Although cuterebrid bot flies are among the physically largest and most-studied insect parasites of mammals, the only study conducted on metabolic consequences of bot fly parasitism revealed a surprisingly small effect of bot flies on host metabolism. Here we test the prediction that bot fly parasitism increases the resting metabolic rate (RMR) of free-ranging eastern chipmunks (Tamias striatus), particularly in juveniles who have not previously encountered parasites and have to allocate energy to growth. We found no effect of bot fly parasitism on adults. In juveniles, however, we found that RMR strongly increased with the number of bot fly larvae hosted. For a subset of 12 juveniles during a year where parasite prevalence was particularly high, we also compared the RMR before versus during the peak of bot fly prevalence, allowing each individual to act as its own control. Each bot fly larva resulted in a ~7.6% increase in the RMR of its host while reducing juvenile growth rates. Finally, bot fly parasitism at the juvenile stage was positively correlated with adult stage RMR, suggesting persistent effects of bot flies on RMR. This study is the first to show an important effect of bot fly parasitism on the metabolism and growth of a wild mammal. Our work highlights the importance of studying cost of parasitism over multiple years in natural settings, as negative effects on hosts are more likely to emerge in periods of high energetic demand (e.g. growing juveniles) and/or in harsh environmental conditions (e.g. low food availability).     

Genetic Mapping Reveals Sophisticated Responses of Malus domestica to Botryosphaeria dothidea Isolates

Infection by the globally distributed pathogenic fungus Botryosphaeria dothidea (Moug.) Ces. et de Not. causes bot canker on the stems, branches and limbs or causes fruit ring rot (FRR) on the fruit in apple. To investigate the relationship between resistance to bot canker and FRR and among resistance mechanisms in response to different pathogen isolates, 34 major gene loci and six quantitative trait loci (QTLs) for bot canker and FRR resistance/susceptibility were genetically mapped on Malus genome using an F1 hybrid population (Jonathan × Golden Delicious) in 2008 and 2009. None of the QTLs for bot canker and FRR overlapped with the region of the major gene loci. Some of the FRR‐ and bot canker‐associated loci either coincided or overlapped, and some were independent, suggesting that the responses of different organs to the pathogen would be correlated but might deviate from each other. Some major gene loci and QTLs associated with different pathogen isolates of bot canker or, FRR were mapped to different regions of the genome. The results indicated that not only did the resistance mechanisms differ between bot canker and FRR but also that genetic differentiation occurred among pathogen isolates.     

Bot fly parasitism of the red-backed vole: host survival,infection risk,and population growth

Parasites can play an important role in the dynamics of host populations, but empirical evidence remains sparse. We investigated the role of bot fly (Cuterebra spp.) parasitism in red-backed voles (Myodes gapperi) by first assessing the impacts of the parasite on the probability of vole survival under stressful conditions as well as on the reproductive activity of females. We then identified the main factors driving both the individual risk of infection and the abundance of bot flies inside red-backed voles. Finally, we evaluated the impacts of bot fly prevalence on the growth rate of vole populations between mid-July and mid-August. Thirty-six populations of red-backed voles were sampled in the boreal forest of Québec, Canada. The presence and the abundance of parasites in voles, two host life history traits (sex and body condition), three indices of habitat complexity (tree basal area, sapling basal area, coarse woody debris volume), and vole abundance were considered in models evaluating the effects of bot flies on host populations. We found that the probability of survival of red-backed voles in live traps decreased with bot fly infection. Both the individual risk of infection and the abundance of bot flies in red-backed voles were driven mainly by vole abundance rather than by the two host life history traits or the three variables of habitat complexity. Parasitism had population consequences: bot fly prevalence was linked to a decrease in short-term growth rate of vole populations over the summer. We found that bot flies have the potential to reduce survival of red-backed voles, an effect that may apply to large portions of populations. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Evolutionary history of stomach bot flies in the light of mitogenomics

Stomach bot flies (Calyptratae: Oestridae, Gasterophilinae) are obligate endoparasitoids of Proboscidea (i.e. elephants), Rhinocerotidae (i.e. rhinos) and Equidae (i.e. horses and zebras, etc.), with their larvae developing in the digestive tract of hosts with very strong host specificity. They represent an extremely unusual diversity among dipteran, or even insect parasites in general, and therefore provide significant insights into the evolution of parasitism. The phylogeny of stomach bot flies was reconstructed based on extensive mitochondrial genomic data for Cobboldia, Gyrostigma and six of the eight known species of Gasterophilus. The phylogenetic tree, i.e. {Cobboldia, [Gyrostigma, (Gasterophilus pecorum, (Gasterophilus intestinalis, (Gasterophilus haemorrhoidalis, Gasterophilus inermis)), (Gasterophilus nasalis, Gasterophilus nigricornis))]}, provides a strong evolutionary reference to infer several biological patterns for the first time for this group: (i) host shifts of stomach bot flies from elephants to rhinoceroses and then from rhinoceroses to equids; (ii) dispersal with their hosts from the Afrotropical region into the Palaearctic and Oriental regions; (iii) oviposition site, originally on the host head, and egg production positively correlated with distance from the mouth; (iv) attachment of third‐instar larva originally in the stomach, with duodenal and large intestinal positions secondarily derived; and (v) guanine and cytosine enrichment of the mitogenome as an adaptation to larval life in the warm environment of the host digestive tract, combined with the need for a high evolutionary rate to cope with the fast evolution of their mammalian hosts.     

Comments on some recent studies of tsetse‐fly phylogeny and structure

The theory of the ‘gasterophiloid origin of the tsetse fliesxy’ advanced by Pollock (1971, 1973) is not warranted by the arguments presented in support of it. The traditional view that warble and bot flies are monophyletic, and that hence the ‘Gasterophilidae’ can be included as a subordinate group of the Oestridae s.l., remains unrefuted. The claim of Popham & Tenabe (1973, 1974) that no rotation occurs in the male postabdomen of Glossina is erroneous.     

Notes on the Species Hesperis microcalyx FOURN

I prove that Hesperis schischkinii TZVEL . Mat. Gerb. Inst., 21 . 146 (1961) is a synonym of the species Hesperis microcalyx FOURN . Bull. Soc. bot. France, 13 , 351 (1866). I specify and complement the diagnosis of the species Hesperis microcalyx.     

The construction of a simultaneous functional order in nervous systems

We have developed two algorithms that construct a simultaneous functional order in a collection of neural elements using purely functional relations. The input of the first algorithm is a matrix describing the total of covariances of signals carried by the members of the neural collection. The second algorithm proceeds from a matrix describing a primitive inclusion relation among the members of the neural collection that can be determined from coincidences in their signal activity. From this information both algorithms compute a partial functional order in the collection of neural elements. Such an order has an objective existence for the system itself and not only for an external observer. By either merging individual neurons or recruiting previously unspecified ones the partial order is locally transformed into a lattice order. Thus, the simultaneous functional order in a nervous net may become isomorphic with a geometrical order if the system has eneough internal coherence. Simulation experiments were done, both for the neuron-merging and the neuron-recruitment routines, to study the number of individuals in the resulting lattice order as a function of the number of individuals in the underlying partially ordered set.     

Cyanobacteria in rice soils

Cyanobacteria were recovered from each of 38 soil samples collected from local rice fields. Of the 84 species belonging to 31 genera that were isolated, 42 were heterocystous diazotrophic species belonging to 14 genera and the remaining were non-heterocystous. Fischerella, Nostoc and Calothrix were widespread.Z.U.M. Khan is with the Department of Botany, Jahangirnagar University, Savar, Dhaka, Bangladesh. Z.N. Tahmida Begum and M.Z. Hossain are with the Department of Botany and R. Mandal is with the Department of Soil Science, bot at the University of Dhaka, Dhaka-1000, Bangladesh;     

Analysis of Microtubule-Associated-Proteins during IBA-Mediated Adventitious Root Induction Reveals KATANIN Dependent and Independent Alterations of Expression Patterns

Adventitious roots (AR) are post embryonic lateral organs that differentiate from non-root tissues. The understanding of the molecular mechanism which underlies their differentiation is important because of their central role in vegetative plant propagation. Here it was studied how the expression of different microtubule (MT)-associated proteins (MAPs) is affected during AR induction, and whether expression differences are dependent on MT organization itself. To examine AR formation when MTs are disturbed we used two mutants in the MT severing protein KATANIN. It was found that rate and number of AR primordium formed following IBA induction for three days was reduced in bot1-1 and bot1-7 plants. The reduced capacity to form ARs in bot1-1 was associated with altered expression of MAP-encoding genes along AR induction. While the expression of MAP65-4, MAP65-3, AURORA1, AURORA2 and TANGLED, increased in wild-type but not in bot1-1 plants, the expression of MAP65-8 and MDP25 decreased in wild type plants but not in the bot1-1 plant after two days of IBA-treatment. The expression of MOR1 was increased two days after AR induction in wild type and bot1-1 plants. To examine its expression specifically in AR primordium, MOR1 upstream regulatory sequence was isolated and cloned to regulate GFP. Expression of GFP was induced in the primary root tips and lateral roots, in the pericycle of the hypocotyls and in all stages of AR primordium formation. It is concluded that the expression of MAPs is regulated along AR induction and that reduction in KATANIN expression inhibits AR formation and indirectly influences the specific expression of some MAPs.     

Methods of developing a core collection of annual Medicago species

A core collection is a subset of a large germplasm collection that contains accessions chosen to represent the genetic variability of the germplasm collection. The purpose of the core collection is to improve management and use of a germplasm collection. Core collections are usually assembled by grouping accessions and selecting from within these groups. The objective of this study was to compare 11 methods of assembling a core collection of the U.S. National collection of annual Medicago species. These methods differed in their use of passport and evaluation data as well as their selection strategy. Another objective was to compare core collections with sample sizes of 5%, 10% and 17% of the germplasm collection. Core collections assembled with evaluation data and cluster analysis better represented the germplasm collection than core collections assembled based solely on passport data and random selection of accessions, The Relative Diversity and the logarithm methods generated better core collections than the proportional method. The 5% and 10% sample size core collection were judged insufficient to represent the germplasm collection.     

The function of the octamer-binding site in the DRA promoter

The octamer binding site, which is located immediately upstream of the poorly conserved DRA TATA sequence, is important fof high levels of expression of this human major histocompatibility class II gene in B cells. In this study, we demonstrate that the substitution of the DRA TATA sequence with the TATA box from the adenovirus E1b promoter revomes the requirements for the octamer binding site for high levels of expression from DRA promoter. Since only the TATA box from the E1b but bot the DRA promoters binds the TATA binding protein, we conclude that the octamer binding site helps to recruit TBP to the DRA promoter.     

Seed biology and in vitro seed germination of Cypripedium

Abstract

Cypripedium orchids have high horticultural value. The populations of most species are very geographically restricted and they are becoming increasingly rare due to the destruction of native habitats and illegal collection. Reduction of the commercial value through large-scale propagation in vitro is a preferable option to reduce pressure from illegal collection. Cypripedium species are commercially propagated via seed germination in vitro. This review focuses on in vitro seed germination and provides an in-depth analysis of the seed biology of this genus.     

Zur Physiologie und Cytologie der Fettbildung bei Endomyces vernalis

Ohne ZusammenfassungD 93.—Als vorläufige Mitteilung erschien: M. Steiner, Ernährung und Fettbildung bei Endomyces vernalis. Ber. d. Deutsch. bot. Ges. 56, 73, 1938.     

Selective and specific internalization of clostridial C3 ADP‐ribosyltransferases into macrophages and monocytes

The C3 transferases from Clostridium botulinum (C3bot) and Clostridium limosum (C3lim) mono‐ADP‐ribosylate and thereby inactivate RhoA, ‐B and ‐C of eukaryotic cells. Due to their extremely poor cellular uptake, C3 transferases were supposed to be exoenzymes rather than exotoxins, challenging their role in pathogenesis. Here, we report for the first time that low concentrations of both C3lim and C3bot are selectively internalized into macrophages/monocytes in less than 3 h, inducing the reorganization of the actin cytoskeleton by ADP‐ribosylation of Rho. We demonstrate that C3 transferases are internalized into the cytosol of macrophages/monocytes via acidified early endosomes. Bafilomycin A1, an inhibitor of endosomal acidification, protected J774A.1 macrophages and human promyelotic leukaemia cells (HL‐60) from intoxication by C3. Moreover, confocal laser scanning microscopy revealed colocalization of C3 with early endosomes. An extracellular acidic pulse enabled direct translocation of cell surface‐bound C3 across the cytoplasmic membrane to the cytosol. In line with this finding, both C3 proteins exhibited membrane activity in lipid bilayer membranes only under acidic conditions (pH < 5.5). In conclusion, we identified macrophages/monocytes as target cells for clostridial C3 transferases and shed light on their selective uptake mechanism, which might contribute to understand the role of C3 transferases in pathogenesis.     

A hierarchical Bayesian Beta regression approach to study the effects of geographical genetic structure and spatial autocorrelation on species distribution range shifts

Global climate change (GCC) may be causing distribution range shifts in many organisms worldwide. Multiple efforts are currently focused on the development of models to better predict distribution range shifts due to GCC. We addressed this issue by including intraspecific genetic structure and spatial autocorrelation (SAC) of data in distribution range models. Both factors reflect the joint effect of ecoevolutionary processes on the geographical heterogeneity of populations. We used a collection of 301 georeferenced accessions of the annual plant Arabidopsis thaliana in its Iberian Peninsula range, where the species shows strong geographical genetic structure. We developed spatial and nonspatial hierarchical Bayesian models (HBMs) to depict current and future distribution ranges for the four genetic clusters detected. We also compared the performance of HBMs with Maxent (a presence‐only model). Maxent and nonspatial HBMs presented some shortcomings, such as the loss of accessions with high genetic admixture in the case of Maxent and the presence of residual SAC for both. As spatial HBMs removed residual SAC, these models showed higher accuracy than nonspatial HBMs and handled the spatial effect on model outcomes. The ease of modelling and the consistency among model outputs for each genetic cluster was conditioned by the sparseness of the populations across the distribution range. Our HBMs enrich the toolbox of software available to evaluate GCC‐induced distribution range shifts by considering both genetic heterogeneity and SAC, two inherent properties of any organism that should not be overlooked.     

Expression of recA-gene dependent SOS functions in Salmonella typhimurium

Thymine starvation of RecA⁺ Thy^- strains of Salmonella typhimurium does not induce the inhibition of cellular respiration, one of the recA-gene dependent SOS functions. Nevertheless, thymine deprivation is able to produce a normal induction of prophage and thymineless death in these same strains. However, when these mutants are treated, in the presence of thymine, with UV-irradiation or bleomycin, they show a normal inhibition of cellular respiration and other SOS functions. Thus, one injurious treatment (thymine deprivation) may trigger prophage induction but not cessation of respiration, whereas another agent (UV-irradiation) may induce both. Together, these results suggest a possible discrimination in the pathways and conditions of expression of various SOS functions.     

Population ecology of a colonizing species: The pelagic tunicate Thalia democratica

Summary The marine pelagic tunicate Thalia democratica has one of the fastest individual growth rates and shortest generation times of any multicellular animal. Measurements of growth in the laboratory and at sea show that this salp maintains a growth rate of over ten percent in length per hour for much of its life cycle. This salp develops through bot generations in a minimum of two days. This generation time increases to over two weeks under conditions of poorer food or lower temperature. Maternal nutrition and viviparity are among the many specialized adaptations which allow this animal to achieve such rapid growth.     

Synopsis of a new collection of sea spiders (Arthropoda: Pycnogonida) from the Ross Sea,Antarctica

The biodiversity research expedition TAN0204 with RS Tangaroa to the Ross Sea in 2004 yielded a new collection of 2,687 specimens of pycnogonids. As much as 25 different species encompassing 14 genera and eight families were identified and their records are discussed herein. The collection is archived in the Marine Invertebrate Collection of the New Zealand National Institute of Water and Atmospheric Research (NIWA). The majority (69%) of specimens are from the Nymphon australe group (Nymphonidae), although species richness and abundance varied among the stations sampled. The collection includes several specimens from polymerous taxa; Pentanymphon antarcticum (Nymphonidae), Decolopoda australis (Colossendeidae) and Pentapycnon bouvieri (Pycnogonidae). All species were classified based on morphological characters, and DNA sequences (from the 18S, 12S, 16S and COI regions) for 21 of the representative morphotypes are given. The DNA sequences confirmed the species-level distinctiveness of these morphotypes. No species new to science were identified, although further detailed morphometric and/or molecular analyses may reveal cryptic or sibling species, especially in species such as the highly abundant Nymphon australe group. An erratum to this article can be found at     

Estimation of the attraction range of a human bait forAedes albopictus (Diptera,culicidae) adults and its absolute density by a new removal method applicable to populations with immigrants

The attraction range of a human bait for Aedes albopictus (Diptera, Culicidae) adults and its absolute density in the range were estimated by a new removal method which is applicable to populations with immigrants. In this model, the number of mosquitoes removed during the kth collection unit y_k, is expressed as where x₀ is the initial number of mosquitoes in the attraction range, a is an index directly proportional to collection efficiency, b is the number of immgirants per collection unit and s(=e^−a) is the survival rate of mosquitoes in the attraction range per collection unit. From the result of successive two collections with various interval distances, it was considered that Aedes albopictus adults are attracted to a human bait from the distance of 4–5 m in the bamboo forest on the calm day. The applicability of this method for the population census of forest mosquitoes was discussed.