The antioxidant system of sterlet seminal fluid in testes and Wolffian ducts

Oxidative stress is a possible source of spermatozoa function deterioration. Seminal fluid (SF) protects spermatozoa against reactive oxygen species (ROS) attack during development in testes and transit through the reproductive tract. Spermatozoa curvilinear velocity and percent of motile cells as well as changes in thiobarbituric acid-reactive substance (TBARS) content, superoxide dismutase, and catalase activity, and uric acid concentration in SF were evaluated in sterlet sperm collected from testes 24 h after hormone induction of spermiation and from Wolffian ducts at 12, 24, 36, and 60 h after hormone injection (HI). While testicular spermatozoa motility was not initiated in activating medium, Wolffian duct sperm showed low motility at 12 h, significant increase at 24 and 36 h, and decrease at 60 h. Testicular SF was characterized by the highest level of TBARS and activity of studied enzymes compared with SF from Wolffian duct sperm at 24 h post-HI. In fluid from Wolffian duct sperm, a significant increase in TBARS content was shown at 36–60 h post-HI. In contrast to testicular SF, in SF from Wolffian duct sperm, this increase was not counterbalanced by changes in the studied variables of antioxidant system. This may be the source of the observed decrease in spermatozoa motility parameters 60 h post-HI. The results may confirm a dual role of ROS in fish sperm physiology. The data with respect to decrease in sturgeon spermatozoa motility parameters at 60 h post-HI should be taken into account in artificial sturgeon propagation.     

Motility parameters of perch spermatozoa (Perca fluviatilis L.) with cryoprotectors addition

The addition of cryoprotectants during the freezing of semen in liquid nitrogen protects spermatozoa from the negative influence of freezing. Every species needs an appropriate cryoprotectant that has to be experimentally selected. Semen obtained from five perches was diluted with the Kobayashi buffer solution at 1:9 ratio. To determine the influence of cryoprotectants on spermatozoa motility parameters, the same type of buffer solution was applied with the addition of methanol, dimethyl sulfoxide (DMSO) and dimethylacetamide (DMA) using the concentration of 10, 5, 2.5 %, respectively, glycerol (15; 7.5 %), sucrose and trehalose (0.45; 0.225; 0.113 M). After the preparation of such tests, parameters of spermatozoa motility were measured, using the CASA system (Image House CRISMAS Company Ltd.). Among used cryoprotectants, methanol did not cause any effect on the sperm motility parameters. The lowest percentage concentrations of DMA, DMSO, glycerol, sucrose and trehalose did not significantly influence the percentage of motile spermatozoa. Higher concentrations of these compounds considerably lowered all motility parameters. As for glycerol and saccharides, their addition resulted in the lowering of the spermatozoa motility possibly due to a higher viscosity of the solution. However, DMA and DMSO were most probably toxic to perch sperm cells. The obtained results indicate that the best cryoprotectant to be used with perch spermatozoa is methanol.     

Early development and allometric growth patterns in burbot Lota lota L.

This study analyzed the morphological development and allometric growth patterns of Lota lota L. (burbot) larvae reared under controlled laboratory conditions. From hatching to day 50, twenty larvae were sampled each [between 1 and 14 days post-hatch (DPH)] or every second day (between 14 and 50 DPH) and measured under a stereoscopic microscope using analytic software. Based on the external morphology, the different stages during early development of burbot were identified: yolk sac larva 0–8 DPH [3.92–4.37 mm total length (TL)]; preflexion larva 9–26 DPH (4.57–12.06 mm TL); flexion larva (between notochord degradation and its replacement with rays) 28–34 DPH (14.00–16.34 mm TL) and postflexion larva/juvenile 36–50 DPH (18.20–29.27 mm TL). Allometric growth patterns of some parameters (e.g., total length, head length, body length, tail length, head depth, body depth, eye diameter) were modeled by a power function and described by the growth coefficient. Organogenesis and changes of body proportions in burbot larvae were more rapid and complex during the yolk sac and preflexion phase of development as larvae developed most of their sensorial, feeding, respiratory and swimming systems and after notochord flexion, when most morphological changes were related to the progressive transformation from pelagic larva to demersal larva/juvenile.     

Changes in ide Leuciscus idus (L.) females’ reproductive parameters after stimulation with carp pituitary homogenate (CPH) and Ovopel: the effect of domestication?

Three groups (wild—WS, semi-pond—SPS, and pond-cultured—PS) of ide Leuciscus idus (L.) were examined. Each group consisted of 30 females and 10 males, aged 5–8 years. All groups were stimulated with two agents: carp pituitary homogenate (CPH) and a synthetic hormonal preparation Ovopel. The amount of ovulating females decreased in conjunction with females’ domestication level, mainly because of very low efficacy of CPH for pond-reared ide stimulation. The percentage of ovulating females stimulated with Ovopel (97.0 %) was significantly higher comparing to CPH (63.0 %). No significant differences were found in latency time between the groups but spawning synchronization increased in conjunction with ide domestication. The positive correlation between domestication level and latency time, i.e., the higher the domestication level, the higher the latency time, was stated. No significant differences were found in PGSI as well as in total volume of obtained eggs, but groups differed significantly in the number of dry eggs and in number of swollen egg. Significant negative correlation between domestication level and number of swollen eggs, i.e., the higher the domestication level, the lower the number of eggs, was detected. The survival rate at the eyed stage was the highest in WS group (60.4 %) and PS group (57.7 %), and was significantly higher than in SPS group (51.8 %). Eggs obtained after CPH stimulation had higher survival rate at the eyed-egg stage (60.3 %) than eggs obtained from the fish stimulated with Ovopel (53.0 %). The data suggest that some form of domestication appeared in ide cultivated for several generations in carp pond.     

Acclimation of cuttings from different willow genotypes to flooding depth level

Climate change will increase the frequency of extreme rain events, causing more flooding episodes. Willows are usually planted in marginal lands like flood prone areas. For willow plantations developed from rootless cuttings, the establishment phase is crucial, because the cuttings are still developing a shoot and root system and have a higher vulnerability to stress. A flooding episode during this early period may have a negative effect upon plants. We analyzed the responses to flooding of eight willow genotypes, representing important species from the economic and ecological point of view (Salix alba, S. matsudana, S. amygdaloides and S. matsudana × S. nigra hybrids). The treatments started when the plants were 2 months old and lasted for 3 weeks. They were identified as: Control (watered to field capacity); F10 (plants submerged 10 cm above soil surface) and F50 (plants submerged 50 cm above soil surface). The F50 treatment showed a greater growth reduction than the F10 treatment in most clones, either measured in height, diameter or total biomass. Both flooding treatments reduced significantly the root-to-shoot ratio compared to control plants. The F50 treatment increased the leaf nitrogen content and specific leaf area in all genotypes. Both treatments changed plant and leaf traits in different ways according to the depth of the floodwater. These changes may have lasting effects on growth recovery in the post-flooding period. Willow clones with a fast initial growth will be the best option to minimize growth reduction in areas prone to experience flooding episodes.     

Nitrogen mineralization indicators under semi-arid and semi-humid conditions: influence on wheat yield and nitrogen uptake

The objectives were i) to assess indicators for potential nitrogen (N) mineralization and ii) to analyze their relationships for predicting winter wheat (Triticum aestivum L.) growth parameters (yield and N uptake, N_up) in Mollisols of the semi-arid and semi-humid region of the Argentine Pampas. Thirty-six farmer fields were sampled at 0–20 cm. Several N mineralization indicators, wheat grain yield and N_up at physiological maturity stage were assessed. A principal component (PC) analysis was performed using correlated factors to grain yield and N_up. The cluster analysis showed two main groups: high fertility and low fertility soils. In high fertility soils, combining PCs in multiple regression models enhanced the wheat yield and N_up prediction significantly with a high R² (adj R² = 0.71–0.83). The main factors that explained the wheat parameters were associated with water availability and N mineralization indicator, but they differ according to soil fertility.

Abbreviations: N: nitrogen; SOM: soil organic matter; POM: particulate organic matter; SOC: soil organic carbon; SON: soil organic nitrogen; POM-C: particulate organic carbon; POM-N: particulate organic nitrogen; N_an: anaerobic nitrogen; N_hyd: hydrolyzable N; NO₃-N: cold nitrate; N₂₀₅: N determined by spectrometer at 205 nm; N₂₆₀: N determined by spectrometer at 260 nm; Pe: extractable P; N_up: wheat N uptake; NO₃-N: inorganic N in the form of nitrate; FR: fallow rainfalls (March-Seeding rainfall); FLR: flowering rainfalls (October-December rainfall); GFR: grain filling rainfall (November rainfall); CCR: crop growing season rainfall (June-December rainfall); PCA: principal component analysis; PC: principal component; MR: multiple regression     

Biodegradability of Disinfectants in Surface Waters from Buenos Aires: Isolation of an Indigenous Strain Able to Degrade and Detoxify Benzalkonium Chloride

Biodegradability of chlorhexidine (CH), triclosan (TC), and benzalkonium chloride (CBA) has been tested in 18 surface water sampling points in the urban area of Buenos Aires. Sampling points were located in both the Reconquista and the Matanza-Riachuelo basins as well as in the La Plata River. High tolerance to the three disinfectants was found and indigenous strains capable of degrading CBA and TC were isolated. Neither tolerance nor biodegradation were correlated with sewage pollution. A strain that degrades CBA was identified as belonging to the genus Pseudomonas using the API20NE system and 16SRNA sequencing. In batch assays, the strain was capable of degrading 100, 200, and up to 500 mg L^?1 of CBA in 10, 25, and 46 h respectively with specific growth rates (μ) of 0.56, 0.30, and 0.14 h^?1. The efficiency of the process was between 99.5–98.0% in terms of compound removal and between 93.8–89.1% in terms of chemical oxygen demand (COD). The detoxification of the compound as a result of the biodegradation was assessed using Pseudokirchneriella subcapitata, Vibrio fischeri, and Lactuca sativa as test organisms.     

Mercury in the Diatoms of Various Ecological Formations

Mercury is a neurotoxin, its main source in the human organism being fish and seafood. The first level in the marine food web is formed of planktonic and benthic photosynthetic microorganisms, which form a biofilm on the surface of the hard bottom (epilithon) or plants (epiphyton). They are carriers of nutritional as well as toxic substances and pass these on to subsequent levels of the trophic web. Their biomass is often dominated by diatoms. This was the basis for the presented study into Hg accumulation in epilithic, epiphytic and planktonic diatoms, which was carried out in 2012–2013 in the coastal zone of the Puck Lagoon and the Gulf of Gdańsk (southern Baltic). In this coastal area, both micro- and macroorganisms develop particularly intensively. The collected results indicate an increase in Hg concentration in the biofilm during the warm season which, with the lengthening of the vegetative period due to global warming in recent years, is of great significance. As a consequence, the annual mercury load entering the trophic web is larger in comparison with a year in which there is a long, cold winter. An important parameter influencing the accumulation of Hg was the function of those organisms from the biofilm-forming communities. In this case, the highest concentrations of Hg were measured in organisms forming high-profile guilds.     

Effect of <Emphasis Type="Italic">Silene vulgaris</Emphasis> and Heavy Metal Pollution on Soil Microbial Diversity in Long-Term Contaminated Soil

In this study, we analysed the impact of heavy metals and plant rhizodeposition on the structure of indigenous microbial communities in rhizosphere and bulk soil that had been exposed to heavy metals for more than 150 years. Samples of the rhizosphere of Silene vulgaris and non-rhizosphere soils 250 and 450 m from the source of emission that had different metal concentrations were collected for analyses. The results showed that soils were collected 250 m from the smelter had a higher number of Cd-resistant CFU compared with the samples that were collected from 450 m, but no significant differences were observed in the number of total and oligotrophic CFU or the equivalent cell numbers between rhizosphere and non-rhizosphere soils that were taken 250 and 450 m from the emitter. Unweighted pair group method with arithmetic mean (UPGMA) cluster analysis of the denaturing gradient gel electrophoresis (DGGE) profiles, as well as a cluster analysis that was generated on the phospholipid fatty acid (PLFA) profiles, showed that the bacterial community structure of rhizosphere soils depended more on the plant than on the distance and metal concentrations. The sequencing of the 16S rDNA fragments that were excised from the DGGE gel revealed representatives of the phyla Bacteroidetes, Acidobacteria, Gemmatimonadetes, Actinobacteria and Betaproteobacteria in the analysed soil with a predominance of the first three groups. The obtained results demonstrated that the presence of S. vulgaris did not affect the number of CFUs, except for those of Cd-resistant bacteria. However, the presence of S. vulgaris altered the soil bacterial community structure, regardless of the sampling site, which supported the thesis that plants have a higher impact on soil microbial community than metal contamination.