Bighorn sheep show similar in‐host responses to the same pathogen strain in two contrasting environments

Ecological context—the biotic and abiotic environment, along with its influence on population mixing dynamics and individual susceptibility—is thought to have major bearing on epidemic outcomes. However, direct comparisons of wildlife disease events in contrasting ecological contexts are often confounded by concurrent differences in host genetics, exposure histories, or pathogen strains. Here, we compare disease dynamics of a Mycoplasma ovipneumoniae spillover event that affected bighorn sheep populations in two contrasting ecological contexts. One event occurred on the herd''s home range near the Rio Grande Gorge in New Mexico, while the other occurred in a captive facility at Hardware Ranch in Utah. While data collection regimens varied, general patterns of antibody signal strength and symptom emergence were conserved between the two sites. Symptoms appeared in the captive setting an average of 12.9 days postexposure, average time to seroconversion was 24.9 days, and clinical signs peaked at approximately 36 days postinfection. These patterns were consistent with serological testing and subsequent declines in symptom intensity in the free‐ranging herd. At the captive site, older animals exhibited more severe declines in body condition and loin thickness, higher symptom burdens, and slower antibody response to the pathogen than younger animals. Younger animals were more likely than older animals to clear infection by the time of sampling at both sites. The patterns presented here suggest that environment may not be a major determinant of epidemiological outcomes in the bighorn sheep—M. ovipneumoniae system, elevating the possibility that host‐ or pathogen‐factors may be responsible for observed variation.     

Characterization of microsatellite loci from the Malagasy endemic,Tina striata Radlk. (Sapindaceae)

We isolated and characterized 12 polymorphic microsatellite loci in the Malagasy endemic, Tina striata Radlk. (Sapindaceae). The number of alleles per locus ranged from 2 to 6 (N = 28 individuals). Polymorphic information content ranged from 0.132 to 0.767 and observed heterozygosity from 0.154 to 0.800. These markers will be valuable in estimating outcrossing rates and genetic variation in populations of T. striata, and aid in the conservation of populations of T. striata and other closely related species in the Malagasy Sapindaceae.     

A systematic review of management efforts on goatgrass (<Emphasis Type="Italic">Aegilops</Emphasis> spp) dominance

Goatgrass (Aegilops) species are some of the most aggressive invasive plants in the Western U.S. Despite intense management efforts, goatgrass continues to reduce the ecological and economic integrity of natural and agroecological systems. The mismatch between current research outcomes and practical needs of land managers is likely a result of limitations associated with generalizing from single location, treatment, or season studies. We conducted a systematic review of experiments testing control of two dominant goatgrass invaders (A. cylindrica and A. triuncialis) to identify general patterns in treatment efficiency. Using data from 391 separate experiments, we found that experimental treatments were more successful at controlling the dominance of A. cylindrica compared to A. triuncialis. For A. cylindrica, no treatment demonstrated particular utility for control. Treatment of A. cylindrica in the vegetative stage was more effective for control than treatment at other stages. For A. triuncialis, burning and grazing demonstrated effective overall control among all treatments, although grazing produced variable results. Treatment in the fruiting stage of A. triuncialis was more effective for control than treatment at other stages. For both species, multiple applications of a management treatment within a year resulted in no better control than a single application within a year. Additionally, treatments deployed in two consecutive years resulted in better control of both species, than a treatment deployed in a single year. This work highlights promising avenues for more intensive research on goatgrass weed control and suggests that management funding is most effectively utilized when employed across years rather than focused on a single year.     

Crystal structure of a UDP-glucose-specific glycosyltransferase from a Mycobacterium species

Glycosyltransferases (GTs) are a large and ubiquitous family of enzymes that specifically transfer sugar moieties to a range of substrates. Mycobacterium tuberculosis contains a large number of GTs, many of which are implicated in cell wall synthesis, yet the majority of these GTs remain poorly characterized. Here, we report the high resolution crystal structures of an essential GT (MAP2569c) from Mycobacterium avium subsp. paratuberculosis (a close homologue of Rv1208 from M. tuberculosis) in its apo- and ligand-bound forms. The structure adopted the GT-A fold and possessed the characteristic DXD motif that coordinated an Mn(2+) ion. Atypical of most GTs characterized to date, MAP2569c exhibited specificity toward the donor substrate, UDP-glucose. The structure of this ligated complex revealed an induced fit binding mechanism and provided a basis for this unique specificity. Collectively, the structural features suggested that MAP2569c may adopt a "retaining" enzymatic mechanism, which has implications for the classification of other GTs in this large superfamily.     

Risk assessment: A model for predicting cross-species transmission of simian foamy virus from macaques (M. fascicularis) to humans at a monkey temple in Bali, Indonesia

Contact between humans and nonhuman primates (NHPs) frequently occurs at monkey temples (religious sites that have become associated with free-ranging populations of NHPs) in Asia, creating the potential for NHP-human disease transmission. In March 2003 a multidisciplinary panel of experts participated in a workshop designed to model the risk of NHP-human pathogen transmission. The panel developed a risk assessment model to describe the likelihood of cross-species transmission of simian foamy virus (SFV) from temple macaques (Macaca fascicularis) to visitors at monkey temples. SFV is an enzootic simian retrovirus that has been shown to be transmitted from NHPs to humans. In operationalizing the model field data, laboratory data and expert opinions were used to estimate the likelihood of SFV transmission within this context. This model sets the stage for a discussion about modeling as a risk assessment tool and the kinds of data that are required to accurately predict transmission.     

Land use is a determinant of plant pathogen alpha‐ but not beta‐diversity

Little is known about the diversity patterns of plant pathogens and how they change with land use at a broad scale. We employed DNA metabarcoding to describe the diversity and composition of putative plant pathogen communities in three substrates (soil, roots, and leaves) across five major land uses at a national scale. Almost all plant pathogen communities (fungi, oomycetes, and bacteria) showed strong responses to land use and substrate type. Land use category could explain up to 24% of the variance in composition between communities. Alpha‐diversity (richness) of plant pathogens was consistently lower in natural forests than in agricultural systems. In planted forests, there was also generally low pathogen alpha‐diversity in soil and roots, but alpha‐diversity in leaves was high compared with most other land uses. In contrast to alpha‐diversity, differences in within‐land use beta‐diversity of plant pathogens (the predictability of plant pathogen communities within land use) were subtle. Our results show that large‐scale patterns and distributions of putative plant pathogens can be determined using metabarcoding, allowing some of the first landscape level insights into these critically important communities.     

Purification and structural studies of a major scrapie prion protein

Scrapie is a degenerative, neurological disorder caused by a slow infectious agent or prion. Extensively purified preparations of prions were denatured by boiling in sodium dodecyl sulfate and the major protein component (PrP 27-30) was isolated by preparative HPLC size exclusion chromatography after proteinase K digestion. The purified PrP 27-30 molecules were not infectious. Ultraviolet absorption spectra of purified PrP 27-30 demonstrated the absence of covalently linked polynucleotides. Amino acid composition studies showed that PrP 27-30 contains at least 17 naturally occurring amino acids. A single N-terminal amino acid sequence for PrP 27-30 was obtained; the sequence is N-Gly-Gln-Gly-Gly-Gly-Thr-His-Asn-Gln-Trp-Asn-Lys-Pro-Ser-Lys and it does not share homology with any known proteins. The same amino acid sequence was found when an extensively purified preparation of prions aggregated into rods and containing approximately 10(9.5) ID50 U/ml was sequenced directly. Knowledge of the amino acid sequence should permit determination of the genetic origin and replication mechanism of prions.     

Two new species of Myxozoa, Myxobolus inaequus sp. n. and Henneguya theca sp. n. from the brain of a South American knife fish, Eigemannia virescens (V.)

Two new species of Myxozoa from the brain of the green knife fish Eigemannia virescens are described: Myxobolus inaequus sp. n. has an unusually large spore body and extremely unequal polar capsules, and Henneguya theca sp. n. has an attenuated spore encased in a sheath not previously described in other Myxozoa . Only spores of the two species were observed, and infections caused no obvious pathological changes in the brain.