Studies on bucephalid digeneans parasitising molluscs and fishes in Finland. II. The description of Rhipidocotyle fennica n. sp. and its discrimination by principal components analysis

Rhipidocotyle fennica n. sp. (= Rhipidocotyle Type A of Taskinen et al., 1991) from the intestine of Esox lucius in central Finland is described and compared by means of a principal components analysis (PCA) with R. campanula (= Rhipidocotyle Type B of Taskinen et al., 1991). Its cercaria develops in the bivalve Anodonta anatina and the metacercaria occurs in the skin and fins of Rutilus rutilus. The metacercaria is discriminated from that of R. campanula by PCA and is described along with aspects of the chaetotaxy of the cercaria. The new species is distinguished from R. campanula, R. kovalae, R. papillosa and R. septpapillata.     

Microhabitat determines how grazing affects bryophytes in wood-pastures

Wood-pastures are biodiverse biotopes where livestock graze among trees. The diversity of several species groups is related to the structural diversity created by herbivores and by trees, decaying wood and rocks. One of the greatest threats to wood-pastures is abandonment that results in decreased heterogeneity of soil microhabitats as well as encroachment by young trees. We studied the diversity of bryophytes on different microhabitat types (soil, rocks, trees and decaying wood) in grazed and abandoned boreal wood-pastures (48 sites). Most species grew on soil, rocks or both. For both soil and rocks currently grazed sites had higher bryophyte species richness and several individual species also preferred grazed sites over abandoned sites. The grazers increase biodiversity by creating patches of bare soil and exposed rock surfaces. Currently grazed and abandoned sites did not differ significantly in bryophyte species richness on decaying wood or trees, and the overall bryophyte richness on these substrates was quite low due to the scarcity of dead wood and large living deciduous trees with suitable bark conditions. Rare species were observed on all microhabitats, most abundantly on soil and decaying wood. Especially our result on higher richness on rock surfaces shows the complexity of grazing effects on biodiversity. Grazers may affect the biodiversity of a species group that is not consumed by them, on a surface which is not attractive to them. These unobvious interactions should be recalled when planning wood-pasture management and conservation.     

Afforested fields benefit nutrient‐demanding fungi

Impaired ecosystems are converted back to natural ecosystems or some other target stage by means of restoration and management. Due to their agricultural legacy, afforested fields might be valuable compensatory habitats for rare fungal species that require nutrient‐rich forest soils. Using a large‐scale field experiment in Finland, we studied community composition of macrofungi (agarics and boletes) on former fields, which had been afforested as monocultures 20 years ago using native spruce Picea abies, pine Pinus sylvestris, and birch Betula pendula. We studied the effect of soil quality, tree species, and site on community composition and structure. Many nutrient‐demanding as well as rare fungal species were recorded, particularly from pine and spruce plots. Pine plots supported more nutrient‐demanding fungi than birch plots. There was no relationship between soil pH, bulk density, P, N, or Ca, and species richness of nutrient‐demanding fungi. Fungal community composition was more similar within sites than among sites for all tree species. Among sites, spruce plots had the smallest fungal species turnover, and birch plots largest. Within sites, however, fungal species turnover from plot to plot was similar among tree species. Our results indicate that tree species has a relatively mild influence on species composition of fungi after 20 years of succession. Interestingly, the results show that afforested fields can be valuable complementary habitats for rare, red‐listed, and nutrient‐demanding fungal species. Field afforestation is a potential conservation tool that could be used to complement the poor representation of rare habitat types in highly fragmented protected area networks.     

Continuous Grading of Early Fibrosis in NAFLD Using Label-Free Imaging: A Proof-of-Concept Study

Background and Aims

Early detection of fibrosis is important in identifying individuals at risk for advanced liver disease in non-alcoholic fatty liver disease (NAFLD). We tested whether second-harmonic generation (SHG) and coherent anti-Stokes Raman scattering (CARS) microscopy, detecting fibrillar collagen and fat in a label-free manner, might allow automated and sensitive quantification of early fibrosis in NAFLD.

Methods

We analyzed 32 surgical biopsies from patients covering histological fibrosis stages 0–4, using multimodal label-free microscopy. Native samples were visualized by SHG and CARS imaging for detecting fibrillar collagen and fat. Furthermore, we developed a method for quantitative assessment of early fibrosis using automated analysis of SHG signals.

Results

We found that the SHG mean signal intensity correlated well with fibrosis stage and the mean CARS signal intensity with liver fat. Little overlap in SHG signal intensities between fibrosis stages 0 and 1 was observed. A specific fibrillar SHG signal was detected in the liver parenchyma outside portal areas in all samples histologically classified as having no fibrosis. This signal correlated with immunohistochemical location of fibrillar collagens I and III.

Conclusions

This study demonstrates that label-free SHG imaging detects fibrillar collagen deposition in NAFLD more sensitively than routine histological staging and enables observer-independent quantification of early fibrosis in NAFLD with continuous grading.     

Association between environmental stress and epidermal papillomatosis of roach Rutilus rutilus

We studied the association between environmental stress and epidermal papillomatosis of roach Rutilus rutilus L. in Finnish waters using a 'matched pairs' design. Populations impacted by industrial and/or sewage effluents were compared to reference populations from pristine sites. We examined both the prevalence (proportion of diseased fish) and intensity (number of scales covered by tumors) of the disease. Results of Generalized Linear Mixed Models (GLMM) indicated that the risk of papillomatosis was 7.5 times higher in males than females, and increased 1.3 times for every 10 mm increment in fish length. We controlled for the possible effects of fish size, sex and temporal variation through sampling procedures and statistical analyses. Mean prevalence of epidermal papillomatosis was 16.6 and 5.8% in impact and reference populations, respectively (10 population pairs; nfish = 1714). Results of GLMM suggested that the risk of being diseased was 2.7 times higher in the impact than reference populations. Thus, the prevalence of epidermal papillomatosis in roach can be used as an indicator of environmental stress. Results of Linear Mixed Models indicated no difference in the intensity of the disease between impact and reference populations (5 population pairs; nfish = 73; mean+/-SE 10.7+/-1.8 and 11.7+/- 2.9 scales, respectively), although prevalence was higher in impact populations in those 5 population pairs. The possible relationship between environmental stress and intensity of epidermal papillomatosis in natural roach populations remains to be demonstrated.     

Serum, but not monocyte macrophage foam cells derived from low HDL-C subjects, displays reduced cholesterol efflux capacity

The main antiatherogenic function of HDL is to promote the efflux of cholesterol from peripheral cells and transport it to the liver for excretion in a process termed reverse cholesterol transport. The aim of this study was to evaluate the cholesterol efflux capacity in low- and high-HDL subjects by utilizing monocytes and serum from 18 low-HDL and 15 high-HDL subjects. Low and high HDL levels were defined, respectively, as HDL < or =10(th) and HDL > or =90(th) Finnish age/sex-specific percentile. Cholesterol efflux from [(3)H]cholesterol-oleate-acetyl-LDL-loaded monocyte-derived macrophages to standard apolipoprotein A-I (apoA-I), HDL(2), and serum was measured. In addition, cholesterol efflux from acetyl-LDL-loaded human THP-1 macrophages to individual sera (0.5%) derived from the study subjects was evaluated. Cholesterol efflux to apoA-I, HDL(2), and serum from macrophage foam cells derived from low- and high-HDL subjects was similar. The relative ABCA1 and ABCG1 mRNA expression levels in unloaded macrophages, as well as their protein levels in loaded macrophage foam cells, were similar in the two study groups. Cholesterol efflux from THP-1 foam cells to serum recovered from high-HDL subjects was slightly higher than that to serum from low-HDL subjects (P = 0.046). Cholesterol efflux from THP-1 macrophages to serum from study subjects correlated with serum apoB (P = 0.033), apoA-I (P = 0.004), apoA-II (P < 0.0001), and the percentage of apoA-I present in the form of prebeta-HDL (P = 0.0001). Our data reveal that macrophages isolated from either low- or high-HDL subjects display similar cholesterol efflux capacity to exogenous acceptors. However, sera from low-HDL subjects have poorer cholesterol acceptor ability as compared with sera from high-HDL subjects.     

Erythroid Progenitor Cells Expanded from Peripheral Blood without Mobilization or Preselection: Molecular Characteristics and Functional Competence

Background

Continued development of in-vitro procedures for expansion and differentiation of erythroid progenitor cells (EPC) is essential not only in hematology and stem cell research but also virology, in light of the strict erythrotropism of the clinically important human parvovirus B19.

Methodology/Principal Findings

We cultured EPC directly from ordinary blood samples, without ex vivo stem cell mobilization or CD34+ cell in vitro preselection. Profound increase in the absolute cell number and clustering activity were observed during culture. The cells obtained expressed the EPC marker combination CD36, CD71 and glycophorin, but none of the lymphocyte, monocyte or NK markers. The functionality of the generated EPC was examined by an in vitro infection assay with human parvovirus B19, tropic for BFU-E and CFU-E cells. Following infection (i) viral DNA replication and mRNA production were confirmed by quantitative PCR, and (ii) structural and nonstructural proteins were expressed in >50% of the cells. As the overall cell number increased 100–200 fold, and the proportion of competent EPC (CD34+ to CD36+) rose from <0.5% to >50%, the in vitro culture procedure generated the EPC at an efficiency of >10 000-fold. Comparative culturing of unselected PBMC and ex vivo-preselected CD34+ cells produced qualitatively and quantitatively similar yields of EPC.

Conclusions/Significance

This approach yielding EPC directly from unmanipulated peripheral blood is gratifyingly robust and will facilitate the study of myeloid infectious agents such as the B19 virus, as well as the examination of erythropoiesis and its cellular and molecular mechanisms.