Diversity of microorganisms associated with atypical superficial blemishes of potato tubers and pathogenicity assessment

Skin blemishes of potato (Solanum tuberosum L.) tubers can cause severe economical losses to production. Some blemishes are due to known pathogens and others whose causes are unknown are called atypical blemishes. The present work aims at determining the origin of superficial atypical blemishes on a set of 204 tubers coming from 12 different French regions producing potato. The diversity of fungi and Streptomyces bacteria associated with blemishes was investigated by systematic isolation followed by identification by sequencing the internal transcribed spacer of the ribosomal DNA for fungi and by sequencing the 16S ribosomal DNA for bacteria. We found a high microbial diversity represented by 349 fungal isolates belonging to at least 47 different species and 21 bacterial strains of Streptomyces sp. The most represented fungi belonged to the genera Fusarium, Rhizoctonia, Alternaria, Penicillium, and Clonostachys. The pathogenicity of representative isolates was assessed in three bioassays; two bioassays based on single inoculations in previously sterilized potting mixture, and one bioassay based on both single and double inoculations under hydroponic conditions. We fulfilled the Koch’s postulates for Rhizoctonia solani AG 3 producing sclerotia. For other fungal and bacterial strains, our results did not show any causality or relationship between a single isolate or a complex and the occurrence of the blemishes. Moreover, the observation of irregular polygonal sunken corky lesions (polygonal lesions)—the most frequent atypical blemish—on non-inoculated tubers, suggested that the atypical blemishes could as well be a reaction of the plant to stressful environmental conditions.     

Positive feedback control by the gonads on gonadotropin (GTH) and gonadoliberin (GnRH) levels in experimentally matured female silver eels,Anguilla anguilla

Treatment of sham-operated female silver eels with carp pituitary extract stimulated ovarian development and induced increases in pituitary gonadotropin (GTH) and gonadoliberin (GnRH) contents. Both effects of carp pituitary extract were abolished in ovariectomized eels, indicating the involvement of the gonads. Endogenous sexual steroids, the secretion of which was increased during sexual maturation, should be responsible for the stimulation of GTH and GnRH levels. Ovariectomy itself had no significant effect on pituitary GTH and GnRH contents, reflecting the fact that, at the silver stage, sexual steroid levels are too low to exert any significant effect on pituitary GTH and GnRH. The positive feedback control exerted by the gonads on GTH and GnRH levels during sexual maturation, in the eel as well as in some other teleosts, would produce an amplification of the pubertal stimulation of the hypothalamo-pituitary-gonadal axis.     

Production of antibodies in murine mucosal immunization with Toxoplasma gondii excreted/secreted antigens

Toxoplasmagondii RH strain excreted/secreted antigens (ESA) were administrated weekly by the oral route, to two groups of 40 OF1 mice for 4 weeks. One group received ESA associated with cholera toxin (CT+) and the other, ESA only (CT-). Five animals from each group were sacrificed from day 4 (D4) to D49 following the first immunization and their feces and sera were collected and tested by ELISA for IgA, IgG and IgM antibody detection. In feces, IgA antibodies were detected on D4 and on D12 in the CT+ and CT- groups, respectively, and they persisted up to D49. IgG antibodies were detected from D12 to D41 in the CT+ group and on D12 only in the CT- group. No IgM antibodies were detected. In sera, IgA antibodies were detected on D27, D41 and D49 only in the CT+ group. IgG and IgM antibodies were found on D12 and D4, respectively, in the CT+ group and starting from D27 in the CT- group. To our knowledge, this is the first demonstration that ESA, with or without CT, are immunogenic when administrated by the oral route.     

Neighbourhood landscape effect on population kinetics of the fossorial water vole (<Emphasis Type="Italic">Arvicola terrestris scherman</Emphasis>)

This paper addresses the issue of whether landscape structure affects A. terrestris population kinetics on a neighbourhood spatial scale, and if so, at what spatial scale is that effect at its maximum. We investigated how the growth of A. terrestris populations is influenced by the landscape context of parcels used for hay production in the French Jura Mountains. Five landscape metrics (relative area of grassland, mean patch area of grassland, patch density of grassland, woodland patch density in grassland, grassland–woodland edge density) were computed over an increasing radius around each parcel (max. 3 km). Redundancy analysis showed that the extent, rate and early onset of A. terrestris population growth were favoured in open grassland areas. Landscape effects on A. terrestris populations as determined by the five metrics are scale-dependent: mean patch area of grassland, patch density of grassland and woodland patch density in grassland had an impact on a grassland parcel within a neighbourhood radius of about 800 m, while relative area of grassland and grassland–woodland edge density had an impact within a neighbourhood radius of about 400 m. Those findings corroborate earlier hypotheses about a multifactorial regulation of A. terrestris populations and a spatial hierarchy of regulating factors. They have potential implications in terms of landscape management and small mammal pest control.     

Lipid metabolism and cellular features of skeletal muscle and subcutaneous adipose tissue in pigs differing in IGF-II genotype

In pigs, a paternally (pat) imprinted mutation in the IGF-II gene is associated with increased muscle mass and decreased backfat thickness. The aim of this study was to determine whether this mutation influenced cellular, biochemical and metabolic features of skeletal muscle and adipose tissue. Muscle (trapezius) and subcutaneous adipose tissue (SCAT) were collected from pigs (106kg) carrying (Qpat, n=6) or not carrying (qpat, n=7) the mutation. Adipocytes were isolated from those tissues by collagenase treatment. Lipid content and activity of lipogenic enzymes were determined using standard assays. Gene expression levels were determined by real-time PCR. Levels of IGF-II mRNA were higher (P<0.01) in muscle of Qpat than in that of qpat pigs, but they did not differ significantly between the two groups in SCAT. Whereas levels of IGF-I mRNA in muscle were similar in both groups, they were higher (P<0.05) in SCAT of Qpat pigs than in that of qpat pigs. Muscle lipid content and intramuscular adipocyte diameters were not influenced significantly by the IGF-II genotype. In SCAT, the reduction of backfat thickness in Qpat pigs compared with qpat pigs was associated with lower (P<0.05) lipid content and smaller (P<0.05) adipocytes, with no significant genotype-effects on expressions and/or activities of lipogenic enzymes. In summary, our results suggest that the IGF-II mutation altered body composition in pigs by favoring myofiber hypertrophy and repressing adipose cell development in SCAT.     

A repeated cross‐sectional study of the epidemiology of Campylobacter and antimicrobial resistant Enterobacteriaceae in free‐living Canada geese in Guelph,Ontario, Canada

From May through October 2016, we conducted a repeated cross‐sectional study examining the effects of temporal, spatial, flock and demographic factors (i.e. juvenile vs. adult) on the prevalence of Campylobacter and antimicrobial resistant Enterobacteriaceae among 344 fresh faecal samples collected from Canada geese (Branta canadensis) from four locations where birds nested in Guelph, Ontario, Canada. The overall prevalence of Campylobacter among all fresh faecal samples was 9.3% and was greatest in the fall when these birds became more mobile following the nesting season. Based on 40 gene comparative genomic fingerprinting (CGF40), the increase in prevalence noted in the fall was matched by an increase in the number of unique CGF40 subtypes identified. Resistance to colistin was detected most commonly, in 6% of Escherichia coli isolates, and was highest in the late summer months. All colistin‐resistant isolates were negative for the mcr‐1 to mcr‐5 genes; a chromosomal resistance mechanism (PmrB) was identified in all of these isolates. The prevalence of samples with E. coli exhibiting multi‐class resistance or extended spectrum beta‐lactamase was low (i.e. <2% of samples). The intra‐class correlation coefficients, estimated from the variance components of multilevel logistic regression models, indicated that the shedding of Campylobacter and antimicrobial resistant E. coli among geese within a flock (i.e. birds collected from the same site on the same day) was moderately correlated. Spatial, temporal, and spatiotemporal clusters identified using the spatial scan statistic, largely supported the findings from our multi‐level models. Salmonella was not isolated from any of the fresh faecal samples collected suggesting that its prevalence in this population of birds was very low.     

Developmental profiles of GFAP-positive astrocytes in sheep cerebellum

Astroglial account for the largest glial population in the brain and play a variety of vital functions in the development of the central nervous system (CNS). An immunohistochemical study was performed in 19 ovine foetuses ranging from 2 to 5 months of gestation, one newborn lamb and three adult sheep. Using the anit-glial fibrillary acidic protein (GFAP) marker, several variations were found in the degree of GFAP positive (GFAP+) astrocyte distribution between the different zones in the cerebellum of sheep during brain development. Our study indicates that the first appearance of astrocytes from restricted zones in the cerebellum occurs around the eighth week of gestation. Bergmann cells were found to be present from around the 15th week of gestation onwards. Our findings suggest that the maturation of astrocytes begins in the caudal parts of the cerebellum, developing from their initial ventral regions to spread first to dorsal regions radially within the white matter, then followed by the more rostral parts of the cerebellum. Astrocytes were also found to proliferate in the vermis before appearing in the cerebellar hemispheres.     

BiKF AdaMus: a novel research project studying the response and adaptive potential of single species and communities to climate change in combination with other stressors

Introduction

How will the combination of climate-induced physical/chemical changes and anthropogenic pollution impact key species and biodiversity, and thus the ecosystem functions in future?

Discussion

The project AdaMus within the newly founded Biodiversity and Climate Research Centre BiK^F aims to understand the prospective ecosystem stress responses and adaptive potential of species and communities to multiple stressors to provide reliable predictions of future developments in terrestric, aquatic and marine environments.

Conclusion

Long-term experiments with terrestrial, aquatic and marine species and communities will be conducted under IPCC predicted climate conditions. In terrestric and limnic experiments, additional co-stressors such as pesticides and alien species are introduced to test for interactions. In the case of marine plankton, potential consequences of multiple climate-related changes in the physical environment (temperature, salinity and oxygen) will be analysed.     

Usefulness of a commercial equine IgG test and serum protein concentration as indicators of failure of transfer of passive immunity in hospitalized foals

Detection of failure of transfer of passive immunity (FTPI) is important in reducing morbidity and mortality in neonatal foals. We investigated the performance of a commercial equine IgG test (SNAP Foal IgG Test Kit) to diagnose FTPI in hospitalized foals. Furthermore, we evaluated the usefulness of serum total protein (STP) and serum globulin (SG) concentrations as indicators of FTPI. Serum IgG concentration was measured by means of the SNAP test and single radial immunodiffusion, and SG and STP concentrations were determined by means of a clinical chemistry analyzer. Subjects were 67 hospitalized foals <19 days old. The SNAP test was repeated on 37 samples from 29 foals, with identical results for 24 samples (kappa statistic, 0.64; 95% confidence interval [CI], 0.46-0.82). The sensitivity of the SNAP test to detect serum IgG concentration [IgG] < or =400 and < or =800 mg/dl was 90% (95% CI, 71-98%) and 95% (85-99%), respectively, and the specificity was 79% (71-82%) and 52% (39-57%), respectively. Sensitivity for detection of [IgG] < or =400 mg/dl was not affected (P > .05) by plasma fibrinogen concentration, sepsis score, or bacteremia. Specificity for detection of [IgG] < or = 800 mg/dl was lower (P < .05) in foals with sepsis score < or =11 (50% [31-60%] versus 100% [8-100%]) and bacteremia (25% [5-56%] versus 62% [45-62%]). Sensitivity and specificity of [STP] < or = 5.0 g/dl for [IgG] < or =800 mg/dl was 94% (83-99%) and 47% (30-56%), respectively. Performance of the SNAP test in hospitalized foals is impaired because of low specificity, but can have usefulness provided that the properties of the test and characteristics of the foal being examined are considered when interpreting the results. The STP and SG concentrations are poor sole indicators of FTPI in hospitalized foals, but may be useful adjunctive tests.