Suillus: an emerging model for the study of ectomycorrhizal ecology and evolution

Research on mycorrhizal symbiosis has been slowed by a lack of established study systems. To address this challenge, we have been developing Suillus, a widespread ecologically and economically relevant fungal genus primarily associated with the plant family Pinaceae, into a model system for studying ectomycorrhizal (ECM) associations. Over the last decade, we have compiled extensive genomic resources, culture libraries, a phenotype database, and protocols for manipulating Suillus fungi with and without their tree partners. Our efforts have already resulted in a large number of publicly available genomes, transcriptomes, and respective annotations, as well as advances in our understanding of mycorrhizal partner specificity and host communication, fungal and plant nutrition, environmental adaptation, soil nutrient cycling, interspecific competition, and biological invasions. Here, we highlight the most significant recent findings enabled by Suillus, present a suite of protocols for working with the genus, and discuss how Suillus is emerging as an important model to elucidate the ecology and evolution of ECM interactions.

Legume-nodulating rhizobia are widespread in soils and plants across the island of O'ahu, Hawai'i

Legumes and their interaction with rhizobia represent one of the most well-characterized symbioses that are widespread across both natural and agricultural environments. However, larger distribution patterns and host associations on isolated Pacific islands with many native and introduced hosts have not been well-documented. Here, we used molecular and culturing techniques to characterize rhizobia from soils and 24 native and introduced legume species on the island of O'ahu, Hawai'i. We chose two of these isolates to inoculate an endemic legume tree, Erythina sandwicensis to measure nodulation potentials and host benefits. We found that all rhizobia genera can be found in the soil, where only Cupriavidus was found at all sites, although at lower abundance relative to other more common genera such as Rhizobium (and close relatives), Bradyzhizobium, and Devosia. Bradyrhizobium was the most common nodulator of legumes, where the strain Bradyrhizobium sp. strain JA1 is a generalist capable of forming nodules on nine different host species, including two native species. In greenhouse nursery inoculations, the two different Bradyrhizobium strains successfully nodulate the endemic E. sandwicensis; both strains equally and significantly increased seedling biomass in nursery inoculations. Overall, this work provides a molecular-based framework in which to study potential native and introduced rhizobia on one of the most isolated archipelagos on the planet.

Genomic determination of breeding systems and trans-specific evolution of HD MAT genes in suilloid fungi

Studying the signatures of evolution can help to understand genetic processes. Here, we demonstrate how the existence of balancing selection can be used to identify the breeding systems of fungi from genomic data. The breeding systems of fungi are controlled by self-incompatibility loci that determine mating types between potential mating partners, resulting in strong balancing selection at the loci. Within the fungal phylum Basidiomycota, two such self-incompatibility loci, namely HD MAT locus and P/R MAT locus, control mating types of gametes. Loss of function at one or both MAT loci results in different breeding systems and relaxes the MAT locus from balancing selection. By investigating the signatures of balancing selection at MAT loci, one can infer a species' breeding system without culture-based studies. Nevertheless, the extreme sequence divergence among MAT alleles imposes challenges for retrieving full variants from both alleles when using the conventional read-mapping method. Therefore, we employed a combination of read-mapping and local de novo assembly to construct haplotypes of HD MAT alleles from genomes in suilloid fungi (genera Suillus and Rhizopogon). Genealogy and pairwise divergence of HD MAT alleles showed that the origins of mating types predate the split between these two closely related genera. High sequence divergence, trans-specific polymorphism, and the deeply diverging genealogy confirm the long-term functionality and multiallelic status of HD MAT locus in suilloid fungi. This work highlights a genomics approach to studying breeding systems regardless of the culturability of organisms based on the interplay between evolution and genetics.

Fungal Hyphosphere Microbiomes Are Distinct from Surrounding Substrates and Show Consistent Association Patterns

Mat-forming fungi are common in forest and grassland soils across the world, where their activity contributes to important soil ecological processes. These fungi maintain dominance through aggressive and abundant hyphae that modify their internal physical and chemical environments and through these modifications select for what appears to be a suite of mycophilic bacteria. Here, the bacteria associated with the fungal mats of Leucopaxillus gentianeus and Leucopaxillus albissimus from western North America are compared to adjacent nonmat substrates. Within the mats, the bacterial richness and diversity were significantly reduced, and the community composition was significantly different. The bacterial community structure between the two fungal hosts was marginally significant and indicated a shared set of bacterial associates. The genera Burkholderia, Streptomyces, Bacillus, Paenibacillus, and Mycobacterium were significantly abundant within the fungal mats and represent core members of these hypha-rich environments. Comparison with the literature from fungal mat studies worldwide showed that these genera are common and often significantly found within fungal mats, further reinforcing the concept of a mycophilic bacterial guild. These genera are incorporated into a synthesis discussion in the context of our current understanding of the nature of fungal-bacterial interactions and the potential outcomes of these interactions in soil nutrient cycling, plant productivity, and human health. IMPORTANCE Fungi and bacteria are the most abundant and diverse organisms in soils (perhaps more so than any other habitat on earth), and together these microorganisms contribute to broad soil ecosystem processes. There is a suite of bacteria that appears consistently within the physical space called the hyphosphere, the area of influence surrounding fungal hyphae. How these bacteria are selected for, how they are maintained, and what broader ecological functions they perform are subjects of interest in this relatively new field-the cross-kingdom interactions between fungi and bacteria. Understanding their cooccurrence and their interactions can open new realms of understanding in soil ecological processes with global consequences.

Relationship between PET/CT images and KRAS gene mutations in colorectal cancer in Vietnamese patients

OBJECTIVE

We conducted this study to determine the relationship among standardized uptake value (SUV), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) indexes of Flourine-18 fluorodeoxyglucose positron emission tomography/computed tomography18 (FDG-PET/CT) imaging and Kirsten rat sarcoma (KRAS) gene mutations in colorectal cancer (CRC).

PATIENTS AND METHODS

This cross-sectional study was conducted in Bach Mai Hospital from 2020 to 2022. It included newly diagnosed CRC patients who underwent PET/CT examination prior to primary tumor resection. The maximum SUV (SUVmax - SUVmean), MTV, and TLG were considered. All pathologically confirmed CRC patients were accepted with further KRAS mutation status analysis.

RESULTS

We enrolled 63 newly diagnosed CRC patients who underwent PET/CT examination prior to primary tumor resection. Among them, 31 (49.2%) patients had KRAS gene mutation. Patients with KRAS mutation status showed significantly different and higher SUVmax (p-value = 0.025), SUVmax t/b (p-value = 0.013), SUVmax t-b (p-value = 0.014), MTV (p-value = 0.023), and TLG (p-value = 0.011) than patients with WT KRAS. Other characteristics, including age, gender, tumor location, SUVb, SUVmean, SUVmax of lymph nodes, and SUVmax of liver metastasis, were insignificantly different between the two groups of patients with KRAS mutation status. Receiver operating curve analysis showed that the area under the curve was 0.672 for SUVmax (p-value = 0.019), SUVt/b (p-value = 0.045), and SUVt-b (p-value = 0.020).

CONCLUSIONS

We observed a relationship, considering the quantitative parameters (SUVmax, SUVmax, SUVmax t-b, MTV, and TLG), between 18FDG-PET/CT images and the KRAS gene mutation in CRC by analyzing 63 patients prior to treatment.

Fungal Community Shift Along Steep Environmental Gradients from Geothermal Soils in Yellowstone National Park

Geothermal soils offer unique insight into the way extreme environmental factors shape communities of organisms. However, little is known about the fungi growing in these environments and in particular how localized steep abiotic gradients affect fungal diversity. We used metabarcoding to characterize soil fungi surrounding a hot spring-fed thermal creek with water up to 84 °C and pH 10 in Yellowstone National Park. We found a significant association between fungal communities and soil variable principal components, and we identify the key trends in co-varying soil variables that explain the variation in fungal community. Saprotrophic and ectomycorrhizal fungi community profiles followed, and were significantly associated with, different soil variable principal components, highlighting potential differences in the factors that structure these different fungal trophic guilds. In addition, in vitro growth experiments in four target fungal species revealed a wide range of tolerances to pH levels but not to heat. Overall, our results documenting turnover in fungal species within a few hundred meters suggest many co-varying environmental factors structure the diverse fungal communities found in the soils of Yellowstone National Park.

Community RNA-Seq: multi-kingdom responses to living versus decaying roots in soil

Roots are a primary source of organic carbon input in most soils. The consumption of living and detrital root inputs involves multi-trophic processes and multiple kingdoms of microbial life, but typical microbial ecology studies focus on only one or two major lineages. We used Illumina shotgun RNA sequencing to conduct PCR-independent SSU rRNA community analysis ("community RNA-Seq") and simultaneously assess the bacteria, archaea, fungi, and microfauna surrounding both living and decomposing roots of the annual grass, Avena fatua. Plants were grown in 13CO2-labeled microcosms amended with 15N-root litter to identify the preferences of rhizosphere organisms for root exudates (13C) versus decaying root biomass (15N) using NanoSIMS microarray imaging (Chip-SIP). When litter was available, rhizosphere and bulk soil had significantly more Amoebozoa, which are potentially important yet often overlooked top-down drivers of detritusphere community dynamics and nutrient cycling. Bulk soil containing litter was depleted in Actinobacteria but had significantly more Bacteroidetes and Proteobacteria. While Actinobacteria were abundant in the rhizosphere, Chip-SIP showed Actinobacteria preferentially incorporated litter relative to root exudates, indicating this group's more prominent role in detritus elemental cycling in the rhizosphere. Our results emphasize that decomposition is a multi-trophic process involving complex interactions, and our methodology can be used to track the trajectory of carbon through multi-kingdom soil food webs.

Comparative genomics reveals dynamic genome evolution in host specialist ectomycorrhizal fungi

While there has been significant progress characterizing the 'symbiotic toolkit' of ectomycorrhizal (ECM) fungi, how host specificity may be encoded into ECM fungal genomes remains poorly understood. We conducted a comparative genomic analysis of ECM fungal host specialists and generalists, focusing on the specialist genus Suillus. Global analyses of genome dynamics across 46 species were assessed, along with targeted analyses of three classes of molecules previously identified as important determinants of host specificity: small secreted proteins (SSPs), secondary metabolites (SMs) and G-protein coupled receptors (GPCRs). Relative to other ECM fungi, including other host specialists, Suillus had highly dynamic genomes including numerous rapidly evolving gene families and many domain expansions and contractions. Targeted analyses supported a role for SMs but not SSPs or GPCRs in Suillus host specificity. Phylogenomic-based ancestral state reconstruction identified Larix as the ancestral host of Suillus, with multiple independent switches between white and red pine hosts. These results suggest that like other defining characteristics of the ECM lifestyle, host specificity is a dynamic process at the genome level. In the case of Suillus, both SMs and pathways involved in the deactivation of reactive oxygen species appear to be strongly associated with enhanced host specificity.

Does fungal competitive ability explain host specificity or rarity in ectomycorrhizal symbioses?

Two common ecological assumptions are that host generalist and rare species are poorer competitors relative to host specialist and more abundant counterparts. While these assumptions have received considerable study in both plant and animals, how they apply to ectomycorrhizal fungi remains largely unknown. To investigate how interspecific competition may influence the anomalous host associations of the rare ectomycorrhizal generalist fungus, Suillus subaureus, we conducted a seedling bioassay. Pinus strobus seedlings were inoculated in single- or two-species treatments of three Suillus species: S. subaureus, S. americanus, and S. spraguei. After 4 and 8 months of growth, seedlings were harvested and scored for mycorrhizal colonization as well as dry biomass. At both time points, we found a clear competitive hierarchy among the three ectomycorrhizal fungal species: S. americanus > S. subaureus > S. spraguei, with the competitive inferior, S. spraguei, having significantly delayed colonization relative to S. americanus and S. subaureus. In the single-species treatments, we found no significant differences in the dry biomasses of P. strobus seedlings colonized by each Suillus species, suggesting none was a more effective plant symbiont. Taken together, these results indicate that the rarity and anomalous host associations exhibited by S. subaureus in natural settings are not driven by inherently poor competitive ability or host growth promotion, but that the timing of colonization is a key factor determining the outcome of ectomycorrhizal fungal competitive interactions.

Rhizopogon olivaceotinctus increases its inoculum potential in heated soil independent of competitive release from other ectomycorrhizal fungi

Rhizopogon olivaceotinctus is a rarely collected ectomycorrhizal fungus that has been found primarily in California and southern Oregon. Prior work has shown that it (i) is common in soil spore banks associated with pine forests from these areas; (ii) is rare or absent on trees in undisturbed forests in these same areas; (iii) exhibits an increased abundance on pine seedlings following fire or experimental soil heating; and (iv) has spores that are more resistant to heat than those of several other ectomycorrhizal species tested to date. Here, we reject the hypothesis that the increased abundance of the species following soil heating is caused only by reduced competition with other ectomycorrnizal fungi and show instead that heating alone significantly increases the inoculum potential of its spores. We argue that this is likely caused by heat stimulation of the spores, a process that has precedent in saprotrophic fungi and plant seeds. This result, in combination with those of previous studies, shows that Rhizopogon olivaceotinctus is well adapted to fire.

Ectomycorrhizal host specificity in a changing world: can legacy effects explain anomalous current associations?

Despite the importance of ectomycorrhizal (ECM) fungi in forest ecosystems, knowledge about the ecological and co-evolutionary mechanisms underlying ECM host associations remains limited. Using a widely distributed group of ECM fungi known to form tight associations with trees in the family Pinaceae, we characterized host specificity among three unique Suillus-host species pairs using a combination of field root tip sampling and experimental bioassays. We demonstrate that the ECM fungus S. subaureus can successfully colonize Quercus hosts in both field and glasshouse settings, making this species unique in an otherwise Pinaceae-specific clade. Importantly, however, we found that the colonization of Quercus by S. subaureus required co-planting with a Pinaceae host. While our experimental results indicate that gymnosperms are required for the establishment of new S. subaureus colonies, Pineaceae hosts are locally absent at both our field sites. Given the historical presence of Pineaceae hosts before human alteration, it appears the current S. subaureus-Quercus associations represent carryover from past host presence. Collectively, our results suggest that patterns of ECM specificity should be viewed not only in light of current forest community composition, but also as a legacy effect of host community change over time.

Molecular basis of flowering under natural long-day conditions in Arabidopsis

Plants sense light and temperature changes to regulate flowering time. Here, we show that expression of the Arabidopsis florigen gene, FLOWERING LOCUS T (FT), peaks in the morning during spring, a different pattern than we observe in the laboratory. Providing our laboratory growth conditions with a red/far-red light ratio similar to open-field conditions and daily temperature oscillation is sufficient to mimic the FT expression and flowering time in natural long days. Under the adjusted growth conditions, key light signalling components, such as phytochrome A and EARLY FLOWERING 3, play important roles in morning FT expression. These conditions stabilize CONSTANS protein, a major FT activator, in the morning, which is probably a critical mechanism for photoperiodic flowering in nature. Refining the parameters of our standard growth conditions to more precisely mimic plant responses in nature can provide a powerful method for improving our understanding of seasonal response.

Ecological responses to forest age, habitat, and host vary by mycorrhizal type in boreal peatlands

Despite covering vast areas of boreal North America, the ecological factors structuring mycorrhizal fungal communities in peatland forests are relatively poorly understood. To assess how these communities vary by age (younger vs. mature), habitat (fen vs. bog), and host (conifer trees vs. ericaceous shrub), we sampled the roots of two canopy trees (Larix laricina and Picea mariana) and an ericaceous shrub (Ledum groenlandicum) at four sites in northern Minnesota, USA. To characterize the specific influence of host co-occurrence on mycorrhizal fungal community structure, we also conducted a greenhouse bioassay using the same three hosts. Root samples were assessed using Illumina-based high-throughput sequencing (HTS) of the ITS1 rRNA gene region. As expected, we found that the relative abundance of ectomycorrhizal fungi was high on both Larix and Picea, whereas ericoid mycorrhizal fungi had high relative abundance only on Ledum. Ericoid mycorrhizal fungal richness was significantly higher in mature forests, in bogs, and on Ledum hosts, while ectomycorrhizal fungal richness did not differ significantly across any of these three variables. In terms of community composition, ericoid mycorrhizal fungi were more strongly influenced by host while ectomycorrhizal fungi were more influenced by habitat. In the greenhouse bioassay, the presence of Ledum had consistently stronger effects on the composition of ectomycorrhizal, ericoid, and ericoid-ectomycorrhizal fungal communities than either Larix or Picea. Collectively, these results suggest that partitioning HTS-based datasets by mycorrhizal type in boreal peatland forests is important, as their responses to rapidly changing environmental conditions are not likely to be uniform.

Phylogenetic assessment of global Suillus ITS sequences supports morphologically defined species and reveals synonymous and undescribed taxa

The genus Suillus represents one of the most recognizable groups of mushrooms in conifer forests throughout the Northern Hemisphere. Although for decades the genus has been relatively well defined morphologically, previous molecular phylogenetic assessments have provided important yet preliminary insights into its evolutionary history. We present the first large-scale phylogenetic study of the boundaries of each species in the genus Suillus based on the most current internal transcribed spacer (ITS) barcode sequences available inPUBLIC databases, as well as sequencing of 224 vouchered specimens and cultures, 15 of which were type specimens from North America. We found that species boundaries delimited by morphological data are broadly congruent with those based on ITS sequences. However, some species appear to have been described several times under different names, several species groups cannot be resolved by ITS sequences alone, and undescribed taxa are apparent, especially in Asia. Therefore, we elevated S. tomentosus var. discolor to S. discolor; proposed synonymies of S. neoalbidipes with S. glandulosipes, S. borealis with S. brunnescens, Boletus serotinus and B. solidipes with Suillus elbensis, S. lactifluus with S. granulatus, S. himalayensis with S. americanus; and proposed usage of the names S. clintonianus in the place of the North American S. grevillei, S. weaverae for North American S. granulatus, S. ampliporus in the place of the North American S. cavipes, and S. elbensis in place of the North American S. viscidus. We showed that the majority of Suillus species have strong affinities for particular host genera. Although deep node support was low, geographic differentiation was apparent, with species from North America, Eurasia, and Asia often forming their own clades. Collectively, this comprehensive genus-level phylogenetic integration of currently available Suillus ITS molecular data and metadata will aid future taxonomic and ecological work on an important group of ectomycorrhizal fungi.

Ethnic disparities in progression to advanced liver disease and overall survival in patients with chronic hepatitis C: impact of a sustained virological response

BACKGROUND

Chronic hepatitis C (CHC) can lead to cirrhosis and hepatocellular carcinoma (HCC). A sustained virological response (SVR) is associated with improved outcomes, however, its impact on different ethnic groups is unknown.

AIM

To evaluate ethnic differences in the natural history of CHC and the impact of SVR.

METHODS

We conducted a cohort study of 8039 consecutive adult CHC patients seen at two medical centres in California between January 1997 and June 2016. Individual chart review confirmed CHC diagnosis.

RESULTS

Asian and Hispanic but not African American patients had significantly higher cirrhosis and HCC incidence than Caucasians. On multivariate analysis, Hispanic ethnicity was independently associated with increased cirrhosis (adjusted HR 1.37, CI, confidence interval 1.10-1.71, P=.006) and HCC risk (adjusted HR 1.47, CI 1.13-1.92, P=.004) compared to Caucasian. Asian ethnicity had a significant association with cirrhosis (adjusted HR 1.28, CI 1.02-1.61, P=.034) and HCC risk (adjusted HR 1.29, CI 0.94-1.77, P=.025). In patients who achieved SVR, Hispanic ethnicity was no longer independently associated with cirrhosis (adjusted HR 1.76, CI 0.66-4.71, P=.26) or HCC (adjusted HR 1.05, CI 0.27-4.08, P=.94); nor was Asian ethnicity (adjusted HR 0.62, CI 0.21-1.82, P=.38 for cirrhosis; 2.01, CI 0.63-6.36, P=.24 for HCC). Similar findings were observed with overall survival among the ethnicities by SVR status.

CONCLUSION

Hispanic and Asian ethnicity was independently associated with increased cirrhosis and HCC risk. Achieving an SVR eliminates the ethnic disparity in liver disease progression and overall survival between Hispanic and Asian vs Caucasian CHC patients.

Ectomycorrhizal fungal response to warming is linked to poor host performance at the boreal-temperate ecotone

Rising temperatures associated with climate change have been shown to negatively affect the photosynthetic rates of boreal forest tree saplings at their southern range limits. To quantify the responses of ectomycorrhizal (EM) fungal communities associated with poorly performing hosts, we sampled the roots of Betula papyrifera and Abies balsamea saplings growing in the B4Warmed (Boreal Forest Warming at an Ecotone in Danger) experiment. EM fungi on the root systems of both hosts were compared from ambient and +3.4 °C air and soil warmed plots at two sites in northern Minnesota. EM fungal communities were assessed with high-throughput sequencing along with measures of plant photosynthesis, soil temperature, moisture, and nitrogen. Warming selectively altered EM fungal community composition at both the phylum and genus levels, but had no significant effect on EM fungal operational taxonomic unit (OTU) diversity. Notably, warming strongly favored EM Ascomycetes and EM fungi with short-contact hyphal exploration types. Declining host photosynthetic rates were also significantly inversely correlated with EM Ascomycete and EM short-contact exploration type abundance, which may reflect a shift to less carbon demanding fungi due to lower photosynthetic capacity. Given the variation in EM host responses to warming, both within and between ecosystems, better understanding the link between host performance and EM fungal community structure will to clarify how climate change effects cascade belowground.

Continental-level population differentiation and environmental adaptation in the mushroom Suillus brevipes

Recent advancements in sequencing technology allowed researchers to better address the patterns and mechanisms involved in microbial environmental adaptation at large spatial scales. Here we investigated the genomic basis of adaptation to climate at the continental scale in Suillus brevipes, an ectomycorrhizal fungus symbiotically associated with the roots of pine trees. We used genomic data from 55 individuals in seven locations across North America to perform genome scans to detect signatures of positive selection and assess whether temperature and precipitation were associated with genetic differentiation. We found that S. brevipes exhibited overall strong population differentiation, with potential admixture in Canadian populations. This species also displayed genomic signatures of positive selection as well as genomic sites significantly associated with distinct climatic regimes and abiotic environmental parameters. These genomic regions included genes involved in transmembrane transport of substances and helicase activity potentially involved in cold stress response. Our study sheds light on large-scale environmental adaptation in fungi by identifying putative adaptive genes and providing a framework to further investigate the genetic basis of fungal adaptation.

Effectiveness and tolerability of simeprevir and sofosbuvir in nontransplant and post-liver transplant patients with hepatitis C genotype 1

BACKGROUND

Hepatitis C virus genotype 1a (HCV-1a), prior treatment, cirrhosis and post-transplant status are historically associated with poor treatment responses. The new oral direct-acting agents appear to be effective and safe in these patients.

AIMS

To evaluate the effectiveness and tolerability of simeprevir and sofosbuvir in a diverse real-life cohort of patients, including difficult-to-treat patients.

METHODS

We conducted a retrospective cohort study in 198 consecutive patients with hepatitis C genotype 1 (148 nontransplant, 50 post transplant), who were treated with simeprevir and sofosbuvir for 12 weeks between December 2013 and December 2014. Primary outcome was sustained virological response with undetectable HCV RNA 12 weeks after completion of therapy (SVR12). Risk factors evaluated for lack of SVR12 included HCV 1a (vs. 1b), prior treatment (vs. none), and cirrhosis (vs. no cirrhosis).

RESULTS

SVR12 rates were similar in non- and post-transplant settings, 82% and 88%, respectively. There were no significant differences in adverse events in patients regardless of cirrhosis or transplant status. On multivariate analysis also inclusive of gender and liver transplant status, negative predictors of SVR12 were having at least 2 or 3 risk factors (OR 0.30, 95% CI 0.10-0.87, P = 0.027 or 0.29, 95% CI 0.09-0.85, P = 0.025, respectively).

CONCLUSION

Simeprevir and sofosbuvir combination is a safe and effective regimen for the treatment of non- and post-transplant patients with traditional risk factors for poor treatment response, unless more than 2 difficult-to-treat risk factors are present.

Quantitative genetic properties of four measures of deformity in yellowtail kingfish Seriola lalandi Valenciennes, 1833

The main aim of this study was to estimate the heritability for four measures of deformity and their genetic associations with growth (body weight and length), carcass (fillet weight and yield) and flesh-quality (fillet fat content) traits in yellowtail kingfish Seriola lalandi. The observed major deformities included lower jaw, nasal erosion, deformed operculum and skinny fish on 480 individuals from 22 families at Clean Seas Tuna Ltd. They were typically recorded as binary traits (presence or absence) and were analysed separately by both threshold generalized models and standard animal mixed models. Consistency of the models was evaluated by calculating simple Pearson correlation of breeding values of full-sib families for jaw deformity. Genetic and phenotypic correlations among traits were estimated using a multitrait linear mixed model in ASReml. Both threshold and linear mixed model analysis showed that there is additive genetic variation in the four measures of deformity, with the estimates of heritability obtained from the former (threshold) models on liability scale ranging from 0.14 to 0.66 (SE 0.32-0.56) and from the latter (linear animal and sire) models on original (observed) scale, 0.01-0.23 (SE 0.03-0.16). When the estimates on the underlying liability were transformed to the observed scale (0, 1), they were generally consistent between threshold and linear mixed models. Phenotypic correlations among deformity traits were weak (close to zero). The genetic correlations among deformity traits were not significantly different from zero. Body weight and fillet carcass showed significant positive genetic correlations with jaw deformity (0.75 and 0.95, respectively). Genetic correlation between body weight and operculum was negative (-0.51, P < 0.05). The genetic correlations' estimates of body and carcass traits with other deformity were not significant due to their relatively high standard errors. Our results showed that there are prospects for genetic selection to improve deformity in yellowtail kingfish and that measures of deformity should be included in the recording scheme, breeding objectives and selection index in practical selective breeding programmes due to the antagonistic genetic correlations of deformed jaws with body and carcass performance.

Ectomycorrhizal Fungal Protein Degradation Ability Predicted by Soil Organic Nitrogen Availability

In temperate and boreal forest ecosystems, nitrogen (N) limitation of tree metabolism is alleviated by ectomycorrhizal (ECM) fungi. As forest soils age, the primary source of N in soil switches from inorganic (NH4 (+) and NO3 (-)) to organic (mostly proteins). It has been hypothesized that ECM fungi adapt to the most common N source in their environment, which implies that fungi growing in older forests would have greater protein degradation abilities. Moreover, recent results for a model ECM fungal species suggest that organic N uptake requires a glucose supply. To test the generality of these hypotheses, we screened 55 strains of 13 Suillus species with different ecological preferences for their in vitro protein degradation abilities. Suillus species preferentially occurring in mature forests, where soil contains more organic matter, had significantly higher protease activity than those from young forests with low-organic-matter soils or species indifferent to forest age. Within species, the protease activities of ecotypes from soils with high or low soil organic N content did not differ significantly, suggesting resource partitioning between mineral and organic soil layers. The secreted protease mixtures were strongly dominated by aspartic peptidases. Glucose addition had variable effects on secreted protease activity; in some species, it triggered activity, but in others, activity was repressed at high concentrations. Collectively, our results indicate that protease activity, a key ectomycorrhizal functional trait, is positively related to environmental N source availability but is also influenced by additional factors, such as carbon availability.

The Microbiome of Pinus muricata Ectomycorrhizae: Community Assemblages, Fungal Species Effects, and Burkholderia as Important Bacteria in Multipartnered Symbioses

Bacteria have been observed to grow with fungi, and those that associate with ectomycorrhizal fungi have often been thought of as symbionts that may either increase or decrease ectomycorrhizal formation rate or provide other unaccounted benefits. To explore this symbiosis from a community ecology perspective, we sampled ectomycorrhizal root tips over a 3-year period and used 454 pyrosequencing to identify the bacteria that live inside the ectomycorrhizal root tips. The results showed that fungal community composition within the same soil core and fungal taxonomic identity had a stronger effect on bacterial community composition than sample year or site. Members of the Burkholderiales and Rhizobiales were most highly represented, reflecting many previous reports of these bacteria in association with fungi. The repeated occurrences of these two bacterial orders suggest that they may be symbiotic with their fungal hosts, although the nature of such mechanisms, be it symbiotic diazotrophy or otherwise, remains to be thoroughly tested.

Antibiotic dosing in obesity: the search for optimum dosing strategies

Global obesity has nearly doubled and is now a common occurrence in high-income and developing countries. The World Health Organization estimates that more than 1.4 billion adults are obese. Although the prevalence of obesity is increasing over the last decades, pharmacokinetic evaluations are still conducted in individuals with a body weight of approximately 70 kg. Morbid obesity is associated with several pathophysiological changes that can profoundly affect drug distribution and clearance. There are currently no specific dosing recommendations for antibiotics in obese patients, making dosing suggestions primarily based on pharmacokinetic characteristics of the medications and dosing recommendations in other disease states. Understanding of the pharmacokinetic alterations and maximum doses of antibiotics safely used is paramount to appropriate treatment in the obese population.

Towards a unified paradigm for sequence-based identification of fungi

The nuclear ribosomal internal transcribed spacer (ITS) region is the formal fungal barcode and in most cases the marker of choice for the exploration of fungal diversity in environmental samples. Two problems are particularly acute in the pursuit of satisfactory taxonomic assignment of newly generated ITS sequences: (i) the lack of an inclusive, reliable public reference data set and (ii) the lack of means to refer to fungal species, for which no Latin name is available in a standardized stable way. Here, we report on progress in these regards through further development of the UNITE database (http://unite.ut.ee) for molecular identification of fungi. All fungal species represented by at least two ITS sequences in the international nucleotide sequence databases are now given a unique, stable name of the accession number type (e.g. Hymenoscyphus pseudoalbidus|GU586904|SH133781.05FU), and their taxonomic and ecological annotations were corrected as far as possible through a distributed, third-party annotation effort. We introduce the term 'species hypothesis' (SH) for the taxa discovered in clustering on different similarity thresholds (97-99%). An automatically or manually designated sequence is chosen to represent each such SH. These reference sequences are released (http://unite.ut.ee/repository.php) for use by the scientific community in, for example, local sequence similarity searches and in the QIIME pipeline. The system and the data will be updated automatically as the number of public fungal ITS sequences grows. We invite everybody in the position to improve the annotation or metadata associated with their particular fungal lineages of expertise to do so through the new Web-based sequence management system in UNITE.

Compartmentalized microbial composition, oxygen gradients and nitrogen fixation in the gut of Odontotaenius disjunctus

Coarse woody debris is an important biomass pool in forest ecosystems that numerous groups of insects have evolved to take advantage of. These insects are ecologically important and represent useful natural analogs for biomass to biofuel conversion. Using a range of molecular approaches combined with microelectrode measurements of oxygen, we have characterized the gut microbiome and physiology of Odontotaenius disjunctus, a wood-feeding beetle native to the eastern United States. We hypothesized that morphological and physiological differences among gut regions would correspond to distinct microbial populations and activities. In fact, significantly different communities were found in the foregut (FG), midgut (MG)/posterior hindgut (PHG) and anterior hindgut (AHG), with Actinobacteria and Rhizobiales being more abundant toward the FG and PHG. Conversely, fermentative bacteria such as Bacteroidetes and Clostridia were more abundant in the AHG, and also the sole region where methanogenic Archaea were detected. Although each gut region possessed an anaerobic core, micron-scale profiling identified radial gradients in oxygen concentration in all regions. Nitrogen fixation was confirmed by (15)N2 incorporation, and nitrogenase gene (nifH) expression was greatest in the AHG. Phylogenetic analysis of nifH identified the most abundant transcript as related to Ni-Fe nitrogenase of a Bacteroidetes species, Paludibacter propionicigenes. Overall, we demonstrate not only a compartmentalized microbiome in this beetle digestive tract but also sharp oxygen gradients that may permit aerobic and anaerobic metabolism to occur within the same regions in close proximity. We provide evidence for the microbial fixation of N2 that is important for this beetle to subsist on woody biomass.

The Helvella lacunosa species complex in western North America: cryptic species, misapplied names and parasites

Based on morphology, fungal species have been considered widespread and as a result names of species from Europe or eastern North America were applied to species in western North America. However, DNA sequences have shown that many western taxa are different from their European counterparts; one such case is presented here. Comparisons of ITS and LSU rDNA sequences from ectomycorrhizal root tips and ascomata of specimens identified as Helvella lacunosa from North America, Europe and Asia revealed that the taxa from western North America and Mexico formed a well supported clade different from the eastern North American, European and Asian taxa. Within this western North American clade there are at least four taxa. Here we describe two of these western taxa as new species: Helvella vespertina and Helvella dryophila. Helvella vespertina is a bigger version of H. lacunosa, is variable in hymenial color and shape and forms ectomycorrhizae with conifers; it fruits typically Oct-Jan. Helvella dryophila is characterized by a dark almost black, squat pileus, a light stipe when young, medium size and forms ectomycorrhizae with Quercus species; it fruits Jan-Jun. Due to insufficient material, the two other Helvella taxa are discussed but not formally described here. We also examined the Hypomyces and other mycoparasites associated with the ascomata of Helvella species and discuss misleadingly labeled sequences in public databases.

Selective breeding in fish and conservation of genetic resources for aquaculture

To satisfy increasing demands for fish as food, progress must occur towards greater aquaculture productivity whilst retaining the wild and farmed genetic resources that underpin global fish production. We review the main selection methods that have been developed for genetic improvement in aquaculture, and discuss their virtues and shortcomings. Examples of the application of mass, cohort, within family, and combined between-family and within-family selection are given. In addition, we review the manner in which fish genetic resources can be lost at the intra-specific, species and ecosystem levels and discuss options to best prevent this. We illustrate that fundamental principles of genetic management are common in the implementation of both selective breeding and conservation programmes, and should be emphasized in capacity development efforts. We highlight the value of applied genetics approaches for increasing aquaculture productivity and the conservation of fish genetic resources.

Measuring ectomycorrhizal fungal dispersal: macroecological patterns driven by microscopic propagules

Dispersal plays a prominent role in most conceptual models of community assembly. However, direct measurement of dispersal across a whole community is difficult at ecologically relevant spatial scales. For cryptic organisms, such as fungi and bacteria, the scale and importance of dispersal limitation has become a major point of debate. We use an experimental island biogeographic approach to measure the effects of dispersal limitation on the ecological dynamics of an important group of plant symbionts, ectomycorrhizal fungi. We manipulated the isolation of uncolonized host seedlings across a natural landscape and used a range of molecular techniques to measure the dispersal rates of ectomycorrhizal propagules and host colonization. Some species were prolific dispersers, producing annual spore loads on the order of trillions of spores per km(2). However, fungal propagules reaching host seedlings decreased rapidly with increasing distance from potential spore sources, causing a concomitant reduction in ectomycorrhizal species richness, host colonization and host biomass. There were also strong differences in dispersal ability across species, which correlated well with the predictable composition of ectomycorrhizal communities associated with establishing pine forest. The use of molecular tools to measure whole community dispersal provides a direct confirmation for a key mechanism underlying island biogeography theory and has the potential to make microbial systems a model for understanding the role of dispersal in ecological theory.

Response to pegylated interferon and ribavirin in Asian American patients with chronic hepatitis C genotypes 1 vs 2/3 vs 6

Chronic hepatitis C is generally underappreciated in Asian Americans, and most pivotal studies were conducted in western countries and only included a small numbers of Asian patients. Our goal was to examine and compare treatment outcomes in these patients with genotypes 1 vs 2/3 vs 6. We performed a retrospective cohort study of 167 consecutive treatment-naïve Asian American patients treated with pegylated interferon (PEG IFN) plus ribavirin (RBV) at two community clinics in Northern California from 12/00 to 1/08. Primary outcome was sustained virological response rate by intention-to-treat analysis. The overall completion rate was 76%, and treatment adherence (completion of ≥ 75-80% PEG IFN + RBV dose for ≥ 75-80% of intended duration) was 74%. Significant depression was noted in only 4% of patients. Sustained virologic response in patients with genotype 6 treated for 48 weeks was similar to that seen in those with genotype 2/3 (74%vs 75%, P = 0.89) and significantly higher than those with genotype 1 (74%vs 49%, P = 0.016). On multivariate analysis inclusive of sex, age, body mass index (≤ 25 vs > 25) and viral load, only treatment adherence and genotype (2/3 and 6 treated for 48 weeks) were found to be significant predictors of sustained virologic response. We conclude that significant depression is rare in Asian American patients (4%). Patients with genotype 6 treated for 48 weeks appear to have a similar treatment response rate as patients with genotype 2/3 and a significantly higher response rate than those with genotype 1.

Décrypthon grid - grid resources dedicated to neuromuscular disorders

Thanks to the availability of computational grids and their middleware, a seamless access to computation and storage resources is provided to application developers and scientists. The Décrypthon project is one example of such a high performance platform. In this paper, we present the architecture of the platform, the middleware developed to facilitate access to several servers deployed in France, and the data center for integrating large biological datasets over multiple sites, supported by a new query language and integration of various tools. The SM2PH project represents an example of a biological application that exploits the capacities of the Décrypthon grid. The goal of SM2PH is a better understanding of mutations involved in human monogenic diseases, their impact on the 3D structure of the protein and the subsequent consequences for the pathological phenotypes.

Inoculum potential of Rhizopogon spores increases with time over the first 4 yr of a 99-yr spore burial experiment

In disturbed or pioneer settings, spores and sclerotia of ectomycorrhizal fungi serve as the necessary inoculum for establishment of ectomycorrhizal-dependent trees. Yet, little is known about the persistence of these propagules through time. Here, live field soil was inoculated with known quantities of basidiospores from four pine-associated species of Rhizopogon; these samples were then buried in retrievable containers, and pine seedling bioassays of serially diluted spore samples were used to measure spore viability. In the first 4 yr, no evidence of loss of spore viability was found in the four Rhizopogon species tested, but all four species exhibited dormancy in which a maximum of 1-8% of their spores were initially receptive to pine roots. There were some differences between species in overall inoculum potential of their spores, but all species broke dormancy at a statistically similar rate. This result provides evidence for spore dormancy in a common ectomycorrhizal genus, but it also precludes our ability to estimate the longevity of the spores accurately. Nevertheless these results, coupled with the observed patterns of Rhizopogon spore banks, suggest that at least decade-long durations are likely. As this experiment progresses, the true longevity of the spores will eventually be revealed.

Five novel Candida species in insect-associated yeast clades isolated from Neuroptera and other insects

Ascomycete yeasts are found commonly in the guts of basidioma-feeding beetles but little is known about their occurrence in the gut of other insects. In this study we isolated 95 yeasts from the gut of adult insects in five neuropteran families (Neuroptera: Corydalidae, Chrysopidae, Ascalaphidae, Mantispidae and Hemerobiidae) and a roach (Blattodea: Blattidae). Based on DNA sequence comparisons and other taxonomic characteristics, they were identified as more than 15 species of Saccharomycetes as well as occasional Cryptococcus-like basidiomycete yeasts. Yeast species such as Lachancea fermentati, Lachancea thermotolerans and Hanseniaspora vineae were isolated repeatedly from the gut of three species of corydalids, suggesting a close association of these species and their insect hosts. Among the yeasts isolated in this study 12 were identified as five novel Candida species that occurred in three phylogenetically distinct clades. Molecular phylogenetic analyses showed that Candida chauliodes sp. nov. (NRRL Y-27909T) and Candida corydali sp. nov. (NRRL Y-27910T) were sister taxa in the Candida albicans/ Lodderomyces elongisporus clade. Candida dosseyi sp. nov. (NRRL Y-27950T) and Candida blattae sp. nov. (NRRL Y-27698T) were sister taxa in the Candida intermedia clade. Candida ascalaphidarum sp. nov. (NRRL Y-27908T) fell on a basal branch in a clade containing Candida membranifaciens and many other insect-associated species. Descriptions of these novel yeast species are provided as well as discussion of their ecology in relation to their insect hosts.

Yeasts isolated from plant-associated beetles and other insects: seven novel Candida species near Candida albicans

Yeasts related to Candida albicans were isolated from the digestive tracts of beetles in eight families and various orders of insects such as earwigs, crickets, and roaches, most of which were caught at light traps or in a few cases directly from plant materials. Based on comparisons of DNA sequences and other taxonomic characteristics, a total of 41 isolates were identified as Candida orthopsilosis, Candida pseudorhagii, Candida maltosa, Candida parapsilosis, Candida tropicalis, Candida neerlandica, Lodderomyces elongisporus, and seven new Candida species. The new species and type strains are designated as Candida gigantensis NRRL Y-27736T, Candida bohiensis NRRL Y-27737T, Candida alai NRRL Y-27739T, Candida buenavistaensis NRRL Y-27734T, Candida frijolesensis NRRL Y-48060T, Candida labiduridarum NRRL Y-27940T, and Candida tetrigidarum NRRL Y-48142T. A phylogeny based on SSU and LSU rRNA gene sequences indicated that most of the new species were closely related to members of the C. albicans/L. elongisporus clade, such as C. albicans, Candida dulbliniensis, C. neerlandica, Candida chauliodes, and Candida corydali. Candida alai was placed near this clade, but no closely related sister taxon was identified. The ecology of the insect-associated yeasts is discussed and compared with the results from other studies.

A yeast clade near Candida kruisii uncovered: nine novel Candida species associated with basidioma-feeding beetles

Yeasts similar to Candida kruisii were isolated repeatedly from the digestive tracts of basidioma-feeding beetles, especially nitidulids inhabiting and feeding on a variety of agarics in the southeastern USA and Barro Colorado Island, Panama. Based on the identical sequences of the D1/D2 domains of the LSU rRNA gene (rDNA) and host beetle information, the isolates were grouped into 19 genotypes which varied from C. kruisii by up to 38 nucleotide differences in the D1/D2 region. Phylogenetic analysis of rDNA sequences and phenotypic traits placed the isolates in C. kruisii and in nine undescribed taxa. The new species and type strains are designated as Candida pallodes (NRRL Y-27653(T)), C. tritomae (NRRL Y-27650(T)), C. panamensis (NRRL Y-27657(T)), C. lycoperdinae (NRRL Y-27658(T)), C. atbi (NRRL Y-27651(T)), C. barrocoloradensis (NRRL Y-27934(T)), C. aglyptinia (NRRL Y-27935(T)), C. stri (NRRL Y-48063(T)), and C. gatunensis (NRRL Y-48064(T)). A phylogeny based on analysis of a combined database of sequences of SSU and LSU rDNA and the ITS region showed that the nine new species formed a novel sister clade to C. kruisii that was strongly supported by bootstrap analysis. Candida pallodes, C. tritomae, C. panamensis, and C. lycoperdinae formed one subclade, while C. atbi, C. barrocoloradensis, C. aglyptinia, C. stri, and C. gatunensis formed a second distinct subclade within the larger clade. Candida pallodes and C. atbi showed a strong host specificity to beetle species in the genus Pallodes (Coleoptera: Nitidulidae) collected from a variety of agarics. On the other hand, C. panamensis, C. tritomae, and C. lycoperdinae were associated with several unrelated beetles in Erotylidae, Scarabaeidae, Tenebrionidae, and Curculionidae as well as Lycoperdina ferruginea (Nitidulidae). Candida pallodes, C. tritomae, C. lycoperdinae, and C. atbi have been isolated repeatedly in the USA, while the other five new species have been found only at Barro Colorado Island, Panama.

Morphological and ecological similarities: wood-boring beetles associated with novel xylose-fermenting yeasts, Spathaspora passalidarum gen. sp. nov. and Candida jeffriesii sp. nov

Ascomycete yeasts that both ferment and assimilate xylose were reported previously as associates of insects living in woody substrates. Most notable have been reports of Pichia stipitis-like yeasts that are widely associated with the wood-boring beetle, Odontotaenius disjunctus (Coleoptera: Passalidae), in the eastern United States. Our continuing investigation of insect gut yeasts has lead to the discovery of two new xylose-fermenting yeasts that phylogenetic analysis places as sister taxa. The beetle hosts, O. disjunctus and Phrenapates bennetti (Coleoptera: Tenebrionidae), are similar in habitat and appearance, and the presence of similar gut yeasts is an additional common feature between them. Here we describe the new yeast genus Spathaspora, the type species S. passalidarum, and its sister taxon Candida jeffriesii and discuss their natural history, including a comparison with Pichia stipitis, another member of a guild of xylose-fermenting yeasts with similar metabolic traits. In addition a morphologically distinct yeast ascospore type is described for Spathaspora.

Communities of microbes that inhabit the changing hindgut landscape of a subsocial beetle

Microbes that have adopted endosymbiotic life styles not only have evolved to live in specialized habitats within living organisms, but the living habitats also have evolved to accommodate them. The hindgut of the passalid beetle (Odontotaenius disjunctus) is lined with a cuticle that undergoes dramatic topographic changes during the life cycle of the beetle. This manuscript addresses the changes that have been observed in time and space for the cuticular landscape of the hindgut as well as for the microbial communities within the hindgut. Microbial identity is based on morphology, culture, and extrapolation from previously reported passalid gut inhabitants.

Metschnikowia noctiluminum sp. nov., Metschnikowia corniflorae sp. nov., and Candida chrysomelidarum sp. nov., isolated from green lacewings and beetles

Fourteen yeast isolates belonging to the Metschnikowia clade were isolated from the digestive tracts of lacewings (Neuroptera: Chrysopidae), soldier beetles and leaf beetles (Coleoptera: Cantharidae and Chrysomelidae), and a caddisfly (Trichoptera: Hydropsychidae). The insect hosts were associated with sugary substances of plants, a typical habitat for yeasts in this clade. Based on DNA sequence comparisons and phenetic characters, the yeasts were identified as Candida picachoensis, Candida pimensis, and four undescribed taxa. Among the undescribed taxa, three yeasts were distinguished from one another and from other described taxa by nucleotide differences in the ribosomal DNA repeat, which were sufficient to consider them as new species. Two of the novel yeast species are described as Metschnikowia noctiluminum (NRRL Y-27753(T)) and M. cornifloraespp. nov. (NRRL Y-27750(T)) based in part on production of needle-shaped ascospores, which are found in most Metschnikowia species. Sexual reproduction was not observed in the third new yeast, Candida chrysomelidarumsp. nov. (NRRL Y-27749(T)). A fourth isolate, NRRL Y-27752, was not significantly distinct from Metschnikowia viticola and Candida kofuensis to be described as a new species. Phylogenetic analysis of the D1/D2 loop sequences placed M. noctiluminum within the M. viticola clade, while C. chrysomelidarum was a sister taxon of Candida rancensis. Metschnikowia corniflorae was phylogenetically distinct from other new species and fell outside of the large-spored Metschnikowia group.

Nine new Candida species near C. membranifaciens isolated from insects

14 different yeasts were isolated from the gut of a variety of insects, including beetles, lacewings, fishflies, craneflies, and a cockroach. One of the yeasts was found both in the gut and on the body surface of a beetle larva. Based on ribosomal DNA sequence comparisons and phenotypic characters, the yeasts were identified as Candida membranifaciens, C. tenuis, Pichia nakazawae, and nine undescribed taxa in Saccharomycotina. All the undescribed taxa reproduced only asexually, and they fit within the limits of the polyphyletic genus Candida. The new species and their type strains are Candida blattariae NRRL Y-27703T, C. amphixiae NRRL Y-27704T, C. michaelii NRRL Y-27705T, C. cerambycidarum NRRL Y-27706T, C. gorgasii NRRL Y-27707T, C. endomychidarum NRRL Y-27708T, C. temnochilae NRRL Y-27763T, C. sinolaborantium NRRL Y-27765T, and C. lessepsii NRRL Y-27766T spp. nov. Phylogenetic analysis of combined small and large subunit ribosomal DNA sequences placed C. amphixiae, C. michaelii, C. cerambycidarum, C. gorgasii, C. endomychidarum, and C. lessepsii in a statistically well supported clade with C. blattariae, C. membranifaciens, C. friedrichii, and C. buinensis as sisters to the clade. The other two new taxa, C. temnochilae and C. sinolaborantium, formed an independent clade basal to the major clade containing C. membranifaciens and closely related taxa. C. sinolaborantium occurred in both Panama and the USA, but there were genetic differences between the isolates from the two places.

Responses in residual feed intake in lines of Large White pigs selected for growth rate on restricted feeding (measured on ad libitum individual feeding)

Residual feed intake (RFI) represents the deviation of the actual ad libitum food consumption of each animal from that predicted from combination of growth rate, backfat and metabolic body weight measurements. After 4 years of divergent selection of pigs in lines for either high or low postweaning growth rate on restricted feeding, the high line exhibited a significant reduction in RFI relative to the low line. This indicated, to some extents, a lower energy requirement for maintenance in the high than in the low line, possibly because of reduced physical activity of the animals. Estimates of genetical parameters showed that RFI was moderately heritable and those genetic correlations of RFI with carcass backfat and food conversion ratio were moderate to highly positive.

A novel antigenic variant of Canine parvovirus from a Vietnamese dog

Nine isolates of Canine parvovirus (CPV) were obtained from Vietnamese dogs and cats. One canine isolate showed a unique antigenic property which indicates a novel antigenic variant of CPV-2b when examined with hemagglutination inhibition tests using our monoclonal antibodies, 21C3 and 19D7, which were recently developed. This isolate had an amino acid substitution of residue 426, Asp to Glu, and the same substitution has recently been found in CPV from Italian dogs. This study first showed that such substitution caused an antigenic difference demonstrable by monoclonal antibodies and that a similar evolution may have occurred in CPV in Vietnam.