Cryptosporidium scrofarum n. sp. (Apicomplexa: Cryptosporidiidae) in domestic pigs (Sus scrofa)

We describe the morphological, biological, and molecular characteristics of Cryptosporidium pig genotype II and propose the species name Cryptosporidium scrofarum n. sp. to reflect its prevalence in adult pigs worldwide. Oocysts of C. scrofarum are morphologically indistinguishable from C. parvum, measuring 4.81–5.96 μm (mean = 5.16) × 4.23–5.29 μm (mean = 4.83) with a length to width ratio of 1.07 ± 0.06 (n = 400). Oocysts of C. scrofarum obtained from a naturally infected pig were infectious for 8-week-old pigs but not 4-week-old pigs. The prepatent period in 8-week-old Cryptosporidium-naive pigs was 4–6 days and the patent period was longer than 30 days. The infection intensity of C. scrofarum in pigs was generally low, in the range 250–4000 oocysts per gram of feces. Infected pigs showed no clinical signs of cryptosporidiosis and no pathology was detected. Cryptosporidium scrofarum was not infectious for adult SCID mice, adult BALB/c mice, Mongolian gerbils (Meriones unguiculatus), southern multimammate mice (Mastomys coucha), yellow-necked mice (Apodemus flavicollis), or guinea pigs (Cavia porcellus). Phylogenetic analyses based on small subunit rRNA, actin, and heat shock protein 70 gene sequences revealed that C. scrofarum is genetically distinct from all known Cryptosporidium species.     

Attenuation of virulence of Lawsonia intracellularis after in vitro passages and its effects on the experimental reproduction of porcine proliferative enteropathy

Non-pathogenic Lawsonia intracellularis variants have been obtained through multiple passages in cell culture but there is no information regarding the number of passages necessary to attenuate a pathogenic isolate. The present study evaluated the susceptibility of pigs to L. intracellularis after 10, 20 and 40 passages in vitro. Three groups (six animals/group) were inoculated with pure culture of L. intracellularis on passage 10, 20 or 40 and one group with placebo. The animals were monitored for clinical signs, fecal shedding and serological IgG response during 28 days post-inoculation. Gross and histologic lesions and the level of infection based on the amount of L. intracellularis-specific antigen in the intestinal mucosa identified by immunohistochemistry were evaluated in two animals from each group on days 14, 21 and 28. Animals inoculated with passages 10 and 20 demonstrated proliferative lesions typical of porcine proliferative enteropathy associated with the presence of Lawsonia-specific antigen in the intestinal mucosa. Passage 40-inoculated pigs did not show proliferative lesions or presence of Lawsonia antigen at any time point throughout the study. Similar patterns of the fecal shedding were observed in passage 10 and 20-infected pigs but those infected with passage 40 shed for a short period. Serological IgG responses in passage 10 and 20-inoculated pigs were detected from day 14 post-infection but not at all in passage 40-inoculated animals. These results demonstrate attenuation of the virulence properties of L. intracellularis between 20 and 40 cell passages in vitro. This information will be valuable for design of future experimental models and for studying the mechanisms involved in the attenuation of L. intracellularis virulence.     

The effect of mesoclimate on Collembola diversity in the Zádiel Valley, Slovak Karst (Slovakia)

In 2002–2004 an investigation of Collembola communities in the Zádiel Valley (Slovak Karst, Slovakia) was carried out. The karst valley is characterised by climatic and vegetation inversion. To assess the effect of mesoclimate inversion upon soil Collembola five sites were selected in hypsometric sequence from the karst plateau down the valley: (1) subxerophilous pasture – ass. Glechomo–Festucetum, (2) lime wood – ass. Mercuriali–Tilietum, (3) beech wood – ass. Dentario bulbiferae-Fagetum, (4) maple–hornbeam wood – ass. Aceri–Carpinetum, and (5) secondary oak wood. In total 152 soil Collembola species were collected, the numbers for particular sites ranging between 70 and 108. Evidently higher species richness was observed in soil of the beech wood compared to other selected forest plots. Thirteen species revealed affinity to inversed (wet and cold) stands of beech (3) and maple–hornbeam wood (4), four of them represented montane species, whereas five species clearly preferred thermophilous sites (1, 2, 5). The presence of 11 montane species at the bottom of the gorge (4) documented the inverse character of the site: Ceratophysella sigillata, C. silvatica, Friesea albida, Deutonura albella, D. stachi, Superodontella lamellifera, Tetrodontophora bielanensis, Heteraphorura variotuberculata, Kalaphorura carpenteri, Orthonychiurus rectopapillatus and Plutomurus carpaticus. Abundance of Folsomia quadrioculata significantly correlated with the soil microclimate – moisture (p < 0.01, r = 0.92). Distribution data on Collembola were performed by cluster (PC-ORD) and CCA ordination techniques. Collembolan communities of two neighbouring forest stands with identical soil type (rendzina) – lime (2) and beech wood (3) – were the most similar in species composition. Meso-/microclimatic gradients within a karst landscape play an important role in determining diversity and community structure of the soil Collembola.     

Diffusion weighted magnetic resonance imaging is a feasible method for characterizing regional lymph nodes in canine patients with head and neck disease

In dogs diagnosed with solid tumors, regional lymph node involvement or evidence of distant metastasis can predict worse prognoses and significantly decreased survival. Lymph node size alone has been shown to be insufficient as a predictor for the accurate clinical staging of some canine neoplasia. However, certain regional lymph nodes (including those of the oral cavity) are difficult to access for routine tissue sampling. Diffusion weighted magnetic resonance imaging (MRI) has demonstrated the ability to differentiate metastatic from inflammatory/benign lymph nodes in clinical studies with human cancer patients through the calculation of quantitative values of diffusion termed apparent diffusion coefficients (ADC). The objective of this prospective, exploratory study was to evaluate diffusion‐weighted MRI and ADC as potential methods for detecting metastatic lymph nodes in dogs with naturally occurring disease. We hypothesized that diffusion‐weighted MRI would identify significantly different ADC values between benign and metastatic lymph nodes in a group of canine patients with head or neck disease. Our study population consisted of eight client‐owned canine patients, with a total of 20 lymph nodes evaluated (six metastatic, 14 benign). Our results demonstrated that two of four observers identified a significant difference between the mean ADC values of the benign and metastatic lymph nodes. When data from all four observers were pooled, the difference between the mean apparent diffusion coefficients values of the benign and metastatic lymph nodes did not reach significance (P‐value = 0.0566). Findings indicated that diffusion‐weighted MRI is a feasible method for further characterizing enlarged lymph nodes in dogs with head and neck disease, however measured ADC values did not differ for benign vs. metastatic lymph nodes in this small sample of dogs.     

Stability in reproductive timing and habitat usage of Chinook salmon across six years of varying environmental conditions and abundance

The spatial and temporal distribution of spawning activity by autumn‐run Chinook salmon Oncorhynchus tshawytscha (Walbaum) was examined across multiple years. The study period included two years of extreme drought conditions when water temperatures in the spawning reach of the Stanislaus River were considered sub‐optimal for spawning and egg incubation. Despite varying levels of superimposition, redd counts and densities remained stable and positively associated with river location, indicating that superimposition may be driven by habitat preference rather than the absence of suitable spawning locations. Spawning occurred slightly later during drought years (6–10 days later compared with wetter years). This delay was attributable to deferred migration instead of deferred spawning, and the majority of redds were constructed at water temperatures exceeding the optimal temperature range. As a consequence, estimates of juvenile production during 2014 and 2015 were among the lowest on record. These findings may be related in part to the high hatchery contribution to the population, above‐average temperatures during spawning and incubation, and superimposition rates. Management recommendations include adequate cold‐water storage in the upstream reservoir, refined spawning habitat restoration techniques in the light of superimposition rates and, on a broader system scale, actions that reduce the amount of stray hatchery Chinook salmon.     

Humic products in agriculture: potential benefits and research challenges—a review

Journal of Soils and Sediments - Humic products have been used in cropland agriculture for several decades, but lack of widespread credibility has restricted their use to small proportions of...     

Detection of transgenic and endogenous plant DNA in digesta and tissues of sheep and pigs fed Roundup Ready canola meal

The persistence of plant-derived recombinant DNA in sheep and pigs fed genetically modified (Roundup Ready) canola was assessed by PCR and Southern hybridization analysis of DNA extracted from digesta, gastrointestinal (GI) tract tissues, and visceral organs. Sheep (n = 11) and pigs (n = 36) were fed to slaughter on diets containing 6.5 or 15% Roundup Ready canola. Native plant DNA (high- and low-copy-number gene fragments) and the cp4 epsps transgene that encodes 5-enolpyruvyl shikimate-3-phosphate synthase were tracked in ruminal, abomasal, and large intestinal digesta and in tissue from the esophagus, rumen, abomasum, small and large intestine, liver, and kidney of sheep and in cecal content and tissue from the duodenum, cecum, liver, spleen, and kidney of pigs. High-copy chloroplast-specific DNA (a 520-bp fragment) was detected in all digesta samples, the majority (89-100%) of intestinal tissues, and at least one of each visceral organ sample (frequencies of 3-27%) from sheep and swine. Low-copy rubisco fragments (186- and 540-bp sequences from the small subunit) were present at slightly lower, variable frequencies in digesta (18-82%) and intestinal tissues (9-27% of ovine and 17-25% of porcine samples) and infrequently in visceral organs (1 of 88 ovine samples; 3 of 216 porcine samples). Each of the five cp4 epsps transgene fragments (179-527 bp) surveyed was present in at least 27% of ovine large intestinal content samples (maximum = 64%) and at least 33% of porcine cecal content samples (maximum = 75%). In sheep, transgene fragments were more common in intestinal digesta than in ruminal or abomasal content. Transgene fragments were detected in 0 (esophagus) to 3 (large intestine) GI tract tissues from the 11 sheep and in 0-10 of the duodenal and cecal tissues collected from 36 pigs. The feed-ingested recombinant DNA was not detected in visceral tissues (liver, kidney) of lambs or in the spleen from pigs. Of note, however, one liver and one kidney sample from the pigs (different animals) were positive for a 278-bp fragment of the transgenic cp4 epsps (denoted F3). Examination of genomic libraries from these tissues yielded no conclusive information regarding integration of the fragment into porcine DNA. This study confirms that feed-ingested DNA fragments (endogenous and transgenic) do survive to the terminal GI tract and that uptake into gut epithelial tissues does occur. A very low frequency of transmittance to visceral tissue was confirmed in pigs, but not in sheep. It is recognized that the low copy number of transgenes in GM feeds is a challenge to their detection in tissues, but there was no evidence to suggest that recombinant DNA would be processed in the gut in any manner different from endogenous feed-ingested genetic material.     

Use of two in vitro methods for the detection of anthelmintic resistant nematode parasites on Slovak sheep farms

A survey of the prevalence of anthelmintic resistant nematode populations was conducted on 32 sheep farms in the Slovak Republic. In vitro egg hatch test and larval development tests were used for the detection of resistance to benzimidazole anthelmintics and they were compared with in vivo faecal egg count reduction tests. There was agreement in the declaration of resistance between the faecal egg count reduction test and both in vitro tests. The presence of resistant populations was determined on two farms using egg hatch test. In both farms, the LD(50) values were higher than 0.1 microg TBZ/ml, indicating resistance. By using LD(99) values it might be possible to reveal relatively small proportion of resistant larvae in the population. The prevalence of benzimidazole resistance has not change on Slovak sheep farms during last decade.     

Ecosystem services: Foundations,opportunities, and challenges for the forest products sector

The ecosystem service concept has been proposed as a meaningful framework for natural resource management. In theory it holds concomitant benefit and consequence for the forest product sector. However, numerous barriers impede practitioners from developing concrete and enduring responses to emerging ecosystem service markets, policies, and initiatives. Principle among these barriers is that the ecosystem service concept has a complex history, numerous definitions in use, and an astounding diversity in rationale and application. This article provides a conceptual review of ecosystem services and its economic foundations, distinguishes among several current definitions of the term and their relatedness to strategies in practical application, discusses diverse approaches to valuation, and explores potential for future relevance in forest product and other sectors.