Female ovarian abnormalities and reproductive failure of autumn-spawning herring (Clupea harengus membras) in the Baltic Sea

Fecundity and reproductive potential are important factors to be considered in evaluating trajectories and demographic predictions of fish populations. Therefore, characterizing the nature and quantifying the extent of any reproductive failure should be considered in fisheries studies. Here, we describe morphological changes in developed ovaries of autumn-spawning herring (Clupea harengus membras) caught in the northern Baltic Sea and evaluate the magnitude of this phenomenon during 3 consecutive years. Visibly, abnormal ovaries were histologically characterized by irregular-shaped oocytes in a vitellogenic or final maturation stage with coagulative necrosis and liquefaction of the yolk sphere, degraded follicle membranes, and fibrinous adhesion among oocytes. Such degeneration is presumed to cause complete infertility in the fish. The frequency of fish with abnormal ovaries varied annually between 10 and 15% among all females sampled. However, specific sampling events showed up to 90% females with abnormal gonads. The specific cause of this abnormality remains unknown; however, prevalence was associated with unfavourable environmental conditions encountered before spawning. Thus, ovarian abnormality was positively related to water temperatures, with the highest level found at ≥15°C and negatively related to the frequency of strong winds. The frequency of occurrence of abnormal gonads decreased with the progression of spawning from August to October. The observed abnormality and associated spawning failure will negatively affect the realized fecundity of autumn herring in the Baltic Sea and may act as a limiting factor for recovery of the stock, which has experienced profound depression during the last three decades

An efficient intelligent analysis system for confocal corneal endothelium images

A confocal microscope provides a sequence of images of the corneal layers and structures at different depths from which medical clinicians can extract clinical information on the state of health of the patient's cornea. A hybrid model based on snake and particle swarm optimisation (S-PSO) is proposed in this paper to analyse the confocal endothelium images. The proposed system is able to pre-process images (including quality enhancement and noise reduction), detect cells, measure cell densities and identify abnormalities in the analysed data sets. Three normal corneal data sets acquired using a confocal microscope, and three abnormal confocal endothelium images associated with diseases have been investigated in the proposed system. Promising results are presented and the performance of this system is compared with manual and two morphological based approaches. The average differences between the manual and the automatic cell densities calculated using S-PSO and two other morphological based approaches is 5%, 7% and 13% respectively. The developed system will be deployable as a clinical tool to underpin the expertise of ophthalmologists in analysing confocal corneal images

Trait‐based analysis of subpolar North Atlantic phytoplankton and plastidic ciliate communities using automated flow cytometer

Plankton are an extremely diverse and polyphyletic group, exhibiting a large range in morphological and physiological traits. Here, we apply automated optical techniques, provided by the pulse‐shape recording automated flow cytometer—CytoSense—to investigate trait variability of phytoplankton and plastidic ciliates in Arctic and Atlantic waters of the subpolar North Atlantic. We used the bio‐optical descriptors derived from the CytoSense (light scattering [forward and sideward] and fluorescence [red, yellow/green and orange from chlorophyll a, degraded pigments, and phycobiliproteins, respectively]) and translated them into functional traits to demonstrate ecological trait variability along an environmental gradient. Cell size was the master trait varying in this study, with large photosynthetic microplankton (> 20 μm in cell diameter), including diatoms as single cells and chains, as well as plastidic ciliates found in Arctic waters, while small‐sized phytoplankton groups, such as the picoeukaryotes (< 4 μm) and the cyanobacteria Synechococcus were dominant in Atlantic waters. Morphological traits, such as chain/colony formation and structural complexity (i.e., cellular processes, setae, and internal vacuoles), appear to favor buoyancy in highly illuminated and stratified Arctic waters. In Atlantic waters, small cell size and spherical cell shape, in addition to photo‐physiological traits, such as high internal pigmentation, offer chromatic adaptation for survival in the low nutrient and dynamic mixing waters of the Atlantic Ocean. The use of automated techniques that quantify ecological traits holds exciting new opportunities to unravel linkages between the structure and function of plankton communities and marine ecosystems

Genetic analysis reveals the diversity of larval Gobiidae in a temperate estuary

Using molecular tools to examine Gobiidae, the second most abundant taxon in ichthyoplankton samples in the Gulf of Riga (Baltic Sea), the sand goby Pomatoschistus minutus was the most abundant taxon (82% of all individuals analysed), the common goby Pomatoschistus microps constituted 12% and the black goby Gobius niger 6%. The spatiotemporal distribution of P. microps and G. niger indicated a preference for habitats closer to the river inlet and their abundances increased slightly towards the end of the sampling period in summer. The species composition was interpreted in the context of the prevailing habitat conditions, characterized by extremely low water transparency, low salinity, limited spread of vegetated area and dominance of sandy–muddy substrata

Study of defects in electron irradiated CuInSe2 by positron lifetime spectroscopy

CuInSe2 was studied in the as-grown state and after low-temperature (4 K) 2 MeV electron irradiation. The positron bulk lifetime of 235 ps was measured for the unirradiated sample. The positron bulk lifetime was theoretically calculated and is in good agreement with the experimental value. In addition, the defect-related lifetimes for mono-, di-, and trivacancies are theoretically determined. An increased average positron lifetime indicated after electron irradiation the appearance of open-volume defects, most probably of divacancy type. The disappearance of this defect was observed during annealing below 250 K. Other defects were formed leading to a divacancy signal at least stable up to 600 K in the temperature range above 450 K.Peer reviewe

Pseudo-vitelliform macular detachment and cuticular drusen: Exclusion of 6 candidate genes

Purpose: The etiology and genetic cause of pseudo-vitelliform macular detachment with cuticular drusen (PVMD/CD) are unknown; nor is it clear if this phenotype represents a separate disease entity, or is a sub-phenotype of disorders with overlapping clinical presentation. To answer this question, we screened a cohort of patients affected with PVMD/CD for variation in six plausible candidate genes (ABCA4, VMD2, TIMP-3, peripherin/RDS, fibulin 5 (FIBL5) and complement factor H (CFH)) associated with diseases of overlapping phenotypes. Methods: Twenty-eight patients, diagnosed with pseudo-vitelliform macular detachment and cuticular drusen, were evaluated by clinical examination, fundus photography, fluorescein angiography and autofluorescence imaging. DNA from all study subjects were screened for variants in the ABCA4, VMD2, TIMP-3, peripherin/RDS, FIBL5 and CFH genes by a combination of DHPLC, array screening and direct sequencing. Results: All patients presented with cuticular drusen; pseudo-vitelliform detachment was seen in 21 cases, while atrophic changes following regression of the detachment were seen in the remaining 7 subjects. Visual acuity ranged from 20/20 to CF. The screening revealed an I32V mutation in peripherin/RDS in one patient and 2ABCA4 variants, T897I and G1961E, in 2 more patients. No amino acid-altering variants were detected in VMD2, TIMP-3, and FIBL5 genes. The frequency of the CFH Y402H variant in this cohort corresponded to that detected in the general population. Conclusions: Screening of 6 candidate genes detected possibly disease-associated mutations in only 3/28 (10.7%) of patients presenting with PVMD/CD, eliminating these genes as causal for this phenotype. Copyright © Informa Healthcare USA, Inc