Search results for "Classification"

2002

Analysis of gonad organization and development revealed that Serranus atricauda is a functional simultaneous hermaphrodite. The ovary is classified as asynchronous. Oocyte growth is divided into five stages: stage I (primary growth stage), stage II (yolk vesicle formation), stage III (vitellogenesis), stage IV (oocyte maturation) and stage V (mature egg). The testis is of the unrestricted or lobular spermatogonial type. Spermatogenic cells include spermatogonia, primary and secondary spermatocytes, spermatids (which form cysts in the seminiferous tubules) and spermatozoa (free in the lumen). The histological structure of the gonad and sperm morphology would seem to indicate that this specie…

Isolation of Zebrafish Gonads for RNA Isolation

2013

Piwi proteins and piRNAs are abundant in the gonads of various animal species. Gonads from different developmental stages provide us information regarding the function of piRNAs and the PIWI pathway during germline development. Here we describe methods for gonad and germ cell preparation from different developmental stages of zebrafish. We also describe how to use these gonads to purify and characterize piRNAs.

Changes in the motility patterns of spermatozoa from the rabbit epididymis as assessed by computer-aided sperm motion analysis

1996

Sperm maturation in the epididymis includes changes in their potential for motility that enables spermatozoa to reach the egg and penetrate its investments. The motility characteristics of spermatozoa from the testis, the epididymis, and vas deferens of the rabbit were investigated by computer-assisted sperm analysis (CASA). Various forms of motility were displayed by sperm from different regions of the epididymis released into incubation medium. Testicular sperm were motile, although nonprogressive. The maximum percentage motility was expressed by sperm in the proximal cauda epididymidis, and forward progression was developed by spermatozoa from the distal caput. Once forward progression w…

Involvement of circadian oscillation(s) in the photoperiodic time measurement and the induction of reproductive diapause in a northern Drosophila spe…

2013

An ability to predict forthcoming changes in environmental conditions and get prepared for them in advance is crucial for the survival and reproduction of organisms living in a seasonally changing environment. We have studied the possible involvement of circadian oscillator(s) in the photoperiodic timer controlling seasonal responses by tracing Drosophila montana females' diapause induction in constant darkness and in a classical Nanda-Hamner experiment. Nearly all females developed ovaries in continuous darkness, which shows the direct development to be their default developmental pathway in the absence of photoperiods. In Nanda-Hamner experiment the females' diapause incidence was close t…

Recovery of Historically Contaminated Watercourse Polluted by the Chemical Wood Industry: EROD Activity in Fish as Biomarker

2013

Despite outstanding process alterations over decades, pulp- and paper-mill-contaminated sediments and continuing exposure by the effluents may still have effects on biota. In this study, ecotoxicological impacts in the boreal watercourse were analyzed by measuring ethoxyresorufin-O-deethylase (EROD) induction from wild fish populations and from experimentally exposed fish. In order to assess the role of sediment-borne chemicals, juvenile rainbow trout (Oncorhynchus mykiss) were exposed in the laboratory to the surface sediments of Lake Vatianjarvi and Southern Lake Saimaa, both watercourses impacted by the chemical wood industry for approximately a century. Hepatic EROD activity was also me…

Extensive nuclear gyration and pervasive non-genic transcription during primordial germ cell development in zebrafish.

2020

ABSTRACT Primordial germ cells (PGCs) are the precursors of germ cells, which migrate to the genital ridge during early development. Relatively little is known about PGCs after their migration. We studied this post-migratory stage using microscopy and sequencing techniques, and found that many PGC-specific genes, including genes known to induce PGC fate in the mouse, are only activated several days after migration. At this same time point, PGC nuclei become extremely gyrated, displaying general broad opening of chromatin and high levels of intergenic transcription. This is accompanied by changes in nuage morphology, expression of large loci (PGC-expressed non-coding RNA loci, PERLs) that ar…

Method optimization to measure polybrominated diphenyl ether (PBDE) concentrations in soils of Bratislava, Slovakia.

2010

We modified an analytical method to determine polybrominated diphenyl ethers (PBDEs) in urban soils of Bratislava (Slovakia). Gel permeation chromatography (GPC) introduced as a clean-up step for soil extracts substantially reduced matrix enhancements when PBDEs were measured with gas chromatography-negative chemical ionization-mass spectrometry (GC-NCI-MS). The resulting method proved to be accurate, precise, and showed low detection limits. The sum of 15 PBDE concentrations in surface horizons of Bratislava soils ranged from 87 to 627 pg g(-1). PBDE concentrations were mostly higher in surface than deeper horizons probably because of atmospheric deposition and lack of substantial vertical…

Expression, purification, crystallization and preliminary X-ray analysis of perakine reductase, a new member of the aldo-keto reductase enzyme superf…

2006

Perakine reductase (PR) is a novel member of the aldo-keto reductase enzyme superfamily from higher plants. PR from the plant Rauvolfia serpentina is involved in the biosynthesis of monoterpenoid indole alkaloids by performing NADPH-dependent reduction of perakine, yielding raucaffrinoline. However, PR can also reduce cinnamic aldehyde and some of its derivatives. After heterologous expression of a triple mutant of PR in Escherichia coli, crystals of the purified and methylated enzyme were obtained by the hanging-drop vapour-diffusion technique at 293 K with 100 mM sodium citrate pH 5.6 and 27% PEG 4000 as precipitant. Crystals belong to space group C222(1) and diffract to 2.0 A, with unit-…

The role of mitochondria in sterigmatocystin-induced apoptosis on SH-SY5Y cells

2020

Mitochondria are cellular organelles involved in many crucial functions, such as generation of energy (ATP) and initiation of apoptosis. The aim of the present study was to evaluate the role of mitochondria in the toxicity induced by sterigmatocystin (STE), a mycotoxin produced by fungi of the genus Aspergillus, on SH-SY5Y cells. Our results showed that STE exposure decreased cell viability in a time- and concentration-dependent manner by MTT assay and caused mitochondrial dysfunction, as highlighted by the increase of STE cytotoxicity in cells forced to rely on mitochondrial oxidative phosphorylation. Furthermore, intracellular ATP depletion and increased mitochondrial reactive oxygen spec…

External Versus Internal Metabolic Activation of Polycyclic Aromatic Compounds in Mutagenicity Tests: A Comparison Using Heterologous Expression Syst…

1996

Abstract Benzo[a]pyrene-trans-7,8-dihydrodiol was virtually non-mutagenic to Chinese hamster V79p cells, but was strongly mutagenic to a V79-derived cell line expressing cytochrome P450 1A1, when the cells were exposed separately. In mixed cultures of these two cell types, it showed about 50 % of the mutagenic activity in V79p cells, compared to that observed in the enzyme-proficient cell line, indicating an efficient intercellular transfer of the active metabolite. The benzylic alcohols 1-hydroxymethylpyrene and 6-hydroxymethylbenzo[a]-pyrene were weakly mutagenic to Salmonella typhimurium TA1538 in the absence of a metabolic activation system, but were potent mutagens to a TA1538-derived …