Fish migrate underground: the example of Delminichthys adspersus (Cyprinidae)

Complex aquatic systems of karst harbour a rich but little‐investigated biodiversity. In Croatia and Bosnia–Herzegovina karst, temporal springs are inhabited by a group of minnow‐like fishes that retreat to the associated ground water during dry seasons and spend several months underground. The most abundant species in this group is Delminichthys adspersus (Heckel 1843), which also has the most fragmented distribution range. To determine the population composition and dispersal patterns, and to detect potential underground migration, a large genetic data set comprising 544 specimens of D. adspersus covering most of its distribution area was analysed. Analysis of mitochondrial cytochrome b sequences (～1000 bp) and eight microsatellite loci showed that D. adspersus comprises at least three subpopulations with gene flow occurring among them. Coalescent‐based analysis revealed a complex migration pattern, with several unidirectional dispersal paths, including between temporal springs that share no surface connection. The results of this study suggest the existence of recurrent underground migration of fish in a karst environment and demonstrate the complexity of its hydrological network. The findings are relevant to conservation strategies for endemic karst organisms and karst ecosystems as a whole.     

Expression of human aldo-keto reductase 1C2 in cell lines of peritoneal endometriosis: potential implications in metabolism of progesterone and dydrogesterone and inhibition by progestins

The human aldo-keto reductase AKR1C2 converts 5α-dihydrotestosterone to the less active 3α-androstanediol and has a minor 20-ketosteroid reductase activity that metabolises progesterone to 20α-hydroxyprogesterone. AKR1C2 is expressed in different peripheral tissues, but its role in uterine diseases like endometriosis has not been studied in detail. Some progestins used for treatment of endometriosis inhibit AKR1C1 and AKR1C3, with unknown effects on AKR1C2. In this study we investigated expression of AKR1C2 in the model cell lines of peritoneal endometriosis, and examined the ability of recombinant AKR1C2 to metabolise progesterone and progestin dydrogesterone, as well as its potential inhibition by progestins. AKR1C2 is expressed in epithelial and stromal endometriotic cell lines at the mRNA level. The recombinant enzyme catalyses reduction of progesterone to 20α-hydroxyprogesterone with a 10-fold lower catalytic efficiency than the major 20-ketosteroid reductase, AKR1C1. AKR1C2 also metabolises progestin dydrogesterone to its 20α-dihydrodydrogesterone, with 8.6-fold higher catalytic efficiency than 5α-dihydrotestosterone. Among the progestins that are currently used for treatment of endometriosis, dydrogesterone, medroxyprogesterone acetate and 20α-dihydrodydrogesterone act as AKR1C2 inhibitors with low μM K(i) values in vitro. Their potential in vivo effects should be further studied.     

Intensity of mineralization in the hyporheic zone of the prealpine river Bača (West Slovenia)

Respiratory electron transport system (ETS) activity and oxygen consumption in the interstitial water, and in the fine (i.e. silt) and coarse (sand) sediment fractions from the hyporheic zone of the prealpine river Bača (W Slovenia) have been measured in order to estimate the intensity of potential and actual carbon mineralization through microbial communities. Hyporheic samples from the river bed (RB) and gravel bars (GB) were compared. ETS activity and oxygen consumption of all fractions from the RB did not differ significantly from those from the GB. ETS activity and oxygen consumption of biofilm attached to 1 g of the silt were higher than of that attached to the same mass of the sand. A significant correlation between ETS activity and oxygen consumption indicated that the former should be a good indicator of intensity of bioactivity in hyporheic sediments. The ratio of ETS activity to oxygen consumption (ETS/R ratio) revealed that the oxygen consumption of microorganisms is responsible for approximately 60% of the metabolic potential in the hyporheic sediments. The contributions of different fractions of sediment to the total ETS activity differed between RB and GB. The contribution of microorganisms in the interstitial water and silt was higher in GB than in the RB, but the sand fraction contributed less to potential carbon loss in GB than in the RB. Average total respiratory carbon loss per volume through the hyporheic zone was higher in the RB than in GB. The main reasons suggested are the different intensity of exchange of surface water with the hyporheic zone, and the rate of consolidation of sediments, which is primarily a function of river hydrology and geomorphology. Handling editor: J. Padisak     

Diagnostic pitfalls in the evaluation of fine needle aspiration cytology of the thyroid: correlation with histopathology in 260 cases

Objectives:  Fine needle aspiration cytology (FNAC) of the thyroid is a non-invasive, cost-effective screening procedure that is valuable for distinguishing neoplastic lesions from non-neoplastic nodules. The aim of this study was to determine the diagnostic accuracy of FNACs performed at our institution by correlating FNAC results with histopathological diagnoses.
Methods:  Two hundred and seventy-one aspiration cytology specimens followed by thyroidectomy were included in the study, and the results of 260 adequate FNACs were compared with their histological diagnoses.
Results:  The sensitivity and specificity of thyroid FNAC for detecting neoplasia were 92.6% and 91.6%, respectively. There were 15 (5.7%) false positives and six (2.3%) false negatives.
Conclusions:  The results showed that follicular cells that exhibit some of the features of papillary carcinoma could be observed in a cytology slide of Hashimoto's thyroiditis, leading to a diagnostic pitfall. In addition, cellularity and overlapping cytological criteria in hyperplasia might lead to a false diagnosis.     

Global characterisation factors to assess land use impacts on biotic production

Purpose

The inclusion of land-use activities in life cycle assessment (LCA) has been subject to much debate in the LCA community. Despite the recent methodological developments in this area, the impacts of land occupation and transformation on its long-term ability to produce biomass (referred to here as biotic production potential [BPP]) — an important endpoint for the Area of Protection (AoP) Natural Resources — have been largely excluded from LCAs partly due to the lack of life cycle impact assessment methods.

Materials and methods

Several possible methods/indicators for BPP associated with biomass, carbon balance, soil erosion, salinisation, energy, soil biota and soil organic matter (SOM) were evaluated. The latter indicator was considered the most appropriate for LCA, and characterisation factors for eight land use types at the climate region level were developed.

Results and discussion

Most of the indicators assessed address land-use impacts satisfactorily for land uses that include biotic production of some kind (agriculture or silviculture). However, some fail to address potentially important land use impacts from other life cycle stages, such as those arising from transport. It is shown that the change in soil organic carbon (SOC) can be used as an indicator for impacts on BPP, because SOC relates to a range of soil properties responsible for soil resilience and fertility.

Conclusions

The characterisation factors developed suggest that the proposed approach to characterize land use impacts on BBP, despite its limitations, is both possible and robust. The availability of land-use-specific and biogeographically differentiated data on SOC makes BPP impact assessments operational. The characterisation factors provided allow for the assessment of land-use impacts on BPP, regardless of where they occur thus enabling more complete LCAs of products and services. Existing databases on every country’s terrestrial carbon stocks and land use enable the operability of this method. Furthermore, BPP impacts will be better assessed by this approach as increasingly spatially specific data are available for all geographical regions of the world at a large scale. The characterisation factors developed are applied to the case studies (Part D of this special issue), which show the practical issues related to their implementation.     

Ornithine decarboxylase, transglutaminase, diamine oxidase and total diamines and polyamines in maternal liver and kidney throughout rat pregnancy.

Ornithine decarboxylase (ODC; EC 4.1.1.17), transglutaminase (EC 2.3.2.13), diamine oxidase (DAO; EC 1.4.3.6) and total di- and poly-amines were studied in rat liver and kidney cortex throughout pregnancy. In liver, ODC activity exhibited two major peaks (4.5-5 times the control activities) on days 15 and 17. Also putrescine and spermidine increased biphasically (3-4-fold), but no variation in spermine content was observed. Transglutaminase activity showed slight variations only near the end of gestation. In kidney, ODC activity did not fluctuate significantly during pregnancy, whereas both transglutaminase activity and putrescine content showed three major increases, in very early, middle and late pregnancy. No significant variations in spermidine and spermine were observed. In both organs, DAO activity, very low or undetectable until day 10, dramatically increased (10- and 20-fold in kidney and liver respectively) in the second half of pregnancy, reaching maxima on days 16-17 and 19. The results obtained for transglutaminase, ODC and total di- and poly-amines are interpreted on the basis of hyperplastic and hypertrophic events in the liver and kidney respectively. The behaviour of DAO suggests that the enzyme plays an important role in the control of intracellular diamine concentration.     

Effect of Blood Vessel Segmentation on the Outcome of Electroporation-Based Treatments of Liver Tumors

Electroporation-based treatments rely on increasing the permeability of the cell membrane by high voltage electric pulses applied to tissue via electrodes. To ensure that the whole tumor is covered with sufficiently high electric field, accurate numerical models are built based on individual patient anatomy. Extraction of patient''s anatomy through segmentation of medical images inevitably produces some errors. In order to ensure the robustness of treatment planning, it is necessary to evaluate the potential effect of such errors on the electric field distribution. In this work we focus on determining the effect of errors in automatic segmentation of hepatic vessels on the electric field distribution in electroporation-based treatments in the liver. First, a numerical analysis was performed on a simple ''sphere and cylinder'' model for tumors and vessels of different sizes and relative positions. Second, an analysis of two models extracted from medical images of real patients in which we introduced variations of an error of the automatic vessel segmentation method was performed. The results obtained from a simple model indicate that ignoring the vessels when calculating the electric field distribution can cause insufficient coverage of the tumor with electric fields. Results of this study indicate that this effect happens for small (10 mm) and medium-sized (30 mm) tumors, especially in the absence of a central electrode inserted in the tumor. The results obtained from the real-case models also show higher negative impact of automatic vessel segmentation errors on the electric field distribution when the central electrode is absent. However, the average error of the automatic vessel segmentation did not have an impact on the electric field distribution if the central electrode was present. This suggests the algorithm is robust enough to be used in creating a model for treatment parameter optimization, but with a central electrode.     

Bacillus subtilis RecA and its accessory factors,RecF, RecO,RecR and RecX,are required for spore resistance to DNA double-strand break

Bacillus subtilis RecA is important for spore resistance to DNA damage, even though spores contain a single non-replicating genome. We report that inactivation of RecA or its accessory factors, RecF, RecO, RecR and RecX, drastically reduce survival of mature dormant spores to ultrahigh vacuum desiccation and ionizing radiation that induce single strand (ss) DNA nicks and double-strand breaks (DSBs). The presence of non-cleavable LexA renders spores less sensitive to DSBs, and spores impaired in DSB recognition or end-processing show sensitivities to X-rays similar to wild-type. In vitro RecA cannot compete with SsbA for nucleation onto ssDNA in the presence of ATP. RecO is sufficient, at least in vitro, to overcome SsbA inhibition and stimulate RecA polymerization on SsbA-coated ssDNA. In the presence of SsbA, RecA slightly affects DNA replication in vitro, but addition of RecO facilitates RecA-mediated inhibition of DNA synthesis. We propose that repairing of the DNA lesions generates a replication stress to germinating spores, and the RecA·ssDNA filament might act by preventing potentially dangerous forms of DNA repair occurring during replication. RecA might stabilize a stalled fork or prevent or promote dissolution of reversed forks rather than its cleavage that should require end-processing.     

Morphological details of microorganisms revealed by RCH-microscopy at high magnification —a ready-to-use adaptation of a light microscope

RCH-microscopy (Relief Contrast after Hostounsky) is a new method of optical microscopy in transmitted light developed withLambda Ltd., Prague. This method was used to study bacteria, fungi including yeasts and algae at high magnification. The equipment provides a three-dimensional image of high contrast and resolution. The results of these microscopic observations can be used for both morphological (taxonomical) and ecological studies of microorganisms.