Influence of environmental colors and long-term sex isolation on zebrafish shoaling behavior

Paper description: Zebrafish social behavior is mediated by different means of communication (chemical and visual). The potential influence of environmental coloring on the shoaling preference of Danio rerio has not been studied. Sex-related differences were found. Unlike females, male fish shoaled more with another male and less with a potential sexual partner. We did not find a significant influence of environmental coloring on social preference patterns. These results are an addition to the insufficient literature in this research area, which is generally characterized by underestimation of sex-related differences in the zebrafish social behavior. Abstract: Zebrafish has a complex social behavior and little is known about the role of sexual preference and their environmental social interactions. In this study we investigated the potential influence of environmental colors and shoaling preferences of zebrafish male and female populations, with a focus on visual communication. Males and females were kept for 7 days in gender-isolated tanks, with a specific habitat color for each group: green for males and red for females. After the pre-test period, all the animals were kept separated and 8 noninvasive behavioral tests were conducted in a T-maze, with the application of different visual stimuli. We did not observe any clear influence of environmental coloring on social zebrafish choices. Significant sex-related differences were found in shoaling partner preference (i.e. same sex vs. other sex, one fish vs. three fish) as follows: females showed a tendency to avoid other females and spent more time with males. Male fish did not display a preference between one or three fish stimuli and they shoaled more with another male and less with a potential sexual partner. There was an obvious difference between males and females in responses and selection of shoaling partners. https://doi.org/10.2298/ABS190118015L Received: January 18, 2019; Revised: February 23, 2019; Accepted: March 5, 2019; Published online: March 19, 2019 How to cite this article: Lenzi C, Grasso C, Nicoara M, Savuca A, Ciobica A, Plavan GI, Strungaru SA. Influence of environmental colors and long-term sex isolation on zebrafish shoaling behavior. Arch Biol Sci. 2019;71(2):329-37

Composição, abundância e biomasa sazonal da assembleia de peixes no subestuário do Solís Chico (Estuário do Río de la Plata, Uruguay)

The large estuaries can present long narrow branches called subestuaries or tidal creeks. These types of subsystems are distributed along the Uruguayan coast of the Río de la Plata estuary and are very important as nursery and refuge areas for fish. For the first time, the seasonal composition and abundance of the fish community of the Solís Chico subestuary was studied by using beach and gill nets. Fourteen species, mainly euryhaline (86%) presented a significant representation of juvenile stages. The fish community was dominated by Odontesthes argentinensis, Platanichthys platana, Mugil liza, Brevoortia aurea, Micropogonias furnieri and Paralichthys orbignyanus, similar to adjacent subestuaries. While Micropogonias furnieri and B. aurea were the most abundant species, some other species were rarely caught. A seasonal variation of the fish assemblage abundance was detected, with higher values in autumn showing a positive correlation with temperature. Species that complete their life cycle in the Río de la Plata estuary, some of which are relevant to fisheries (64% of the analyzed species) were captured in the Solís Chico subestuary. The importance of this environment as a transitional system for some estuarine fish species is advised

Life history traits influence in gonad composition of two sympatric species of flatfish

AbstractParalichthys orbignyanus and Paralichthys patagonicus are flatfish with different life history traits, having in common the condition of breeding in seawater. Paralichthys patagonicus remain their whole life in open seawater and Paralichthys orbignyanus are sometimes found in brackish water bodies. As marine and estuarine food webs have different fatty acid (FA) compositions, the aim of this study was to characterize the gonadal maturation of P. orbignyanus and P. patagonicus females through the analysis of lipid content and FA profile in order to understand to what extent life history traits are reflected in the ovarian composition. During gonadal maturation lipid content increased and FA profiles changed in both species, but the lipid increase was greater in P. orbignyanus. The N-3FA and n-3HUFA proportions increased in both species but were higher in P. orbignyanus. The differences between the lifestyles of these species were reflected in the ovarian FA profile mainly as a result of differences in their FA metabolism, causing a greater accumulation of n-3FA and n-3HUFA in P. orbignyanus than in P. patagonicus. The higher lipid accumulation in P. orbignyanus’ ovaries could indicate that this species, feeding in brackish water bodies, has the possibility of storing more energy than P. patagonicus

Kollageeni struktuuris naha töötlemisel tekkivad muutused

The characteristic features of forming the collagen structure in the beam-house process and tanning have been investigated. It is shown that the moderate derma-swelling rate during liming provides effective fixation of the derma structure in tanning. The formation of strong crosslinkages during tanning leads to the change in the deformation character of derma collagen, especially in the compression test. The usage of the glutaric aldehyde by tanning allows to reduce the consumption of chrome compounds or fully exclude them and at the same time to receive soft elastic leather with a high volume yield.On uuritud kollageeni struktuuri naha lupjamisel ja parkimisel. Mõõdukas pundumiskiirus parkimisel tagab derma struktuuri tõhusa kinnistumise. Ristseotiste teke lupjamisel tõstab naha elastsust. Parkimisel tungivad glutaaraldehüüdi molekulid kollageeni struktuuri amorfsetesse piirialadesse ja tekitavad püsivaid ristseotisi, muutes naha pehmemaks ja elastsemaks, ühtlasi vähendades kroomiühendite kulu

Seasonal composition, abundance and biomass of the subestuarine fish assemblage in Solís Chico (Río de la Plata estuary, Uruguay)

Abstract The large estuaries can present long narrow branches called subestuaries or tidal creeks. These types of subsystems are distributed along the Uruguayan coast of the Río de la Plata estuary and are very important as nursery and refuge areas for fish. For the first time, the seasonal composition and abundance of the fish community of the Solís Chico subestuary was studied by using beach and gill nets. Fourteen species, mainly euryhaline (86%) presented a significant representation of juvenile stages. The fish community was dominated by Odontesthes argentinensis, Platanichthys platana, Mugil liza, Brevoortia aurea, Micropogonias furnieri and Paralichthys orbignyanus, similar to adjacent subestuaries. While Micropogonias furnieri and B. aurea were the most abundant species, some other species were rarely caught. A seasonal variation of the fish assemblage abundance was detected, with higher values in autumn showing a positive correlation with temperature. Species that complete their life cycle in the Río de la Plata estuary, some of which are relevant to fisheries (64% of the analyzed species) were captured in the Solís Chico subestuary. The importance of this environment as a transitional system for some estuarine fish species is advised

Design of Electrically Conducting Polymer Hybrid Composites Based on Polyvinyl Chloride and Polyethylene

Interest to electrically conducting polymer composite materials in recent times has grown considerably, which is associated with the design of new branches of science and technology. The existing analogues are different in the complexity of production and high cost. One of the ways of solving the problem may be designing polymer composite materials with a combined filler. The research was carried out on creating electrically conducting hybrid polymer composites, based on emulsion polyvinyl chloride and polyethylene, using fillers of varying nature and dimensions. We studied the dependence of electrical conductivity of mono­ and binary­filled polymer composites on the type and content of fillers. It was found that the binary filling allows designing electrically conducting polymer composites, which are more promising economically compared to mono­filled ones. We defined physical and mechanical characteristics: tensile strength and relative elongation at break of obtained polymer composites. A method to improve them was proposed by introduction of a compatibilizer – graft­polymer of polyethylene with maleic anhydride.Depending on the value of the electrical conductivity, polymer hybrid composites can be used for: at a value of of elecrical conductivity 10–4–10–7Cm/cm as anti­static materials; at 101–10–4 Cm/cm – as scattering anti­static materials, at 101– 104 Cm/cm as current­conducting materials

Physicochemical Analysis and Wound Healing Activity of <i>Azadirachta indica</i> (A. Juss) Fruits

(1) Background: The neem tree, Azadirachta indica (A. Juss), is a well-known species used in traditional medicine for the treatment of skin conditions such as irritation, eczema, burns, and wounds. The objective of the current study was to investigate the physicochemical and wound-healing properties of A. indica fruits. (2) Methods: Gas chromatography coupled with mass spectrometry (GC-MS) was used to determine the content of fatty acids and phytosterols, and high-performance liquid chromatography (HPLC) was used to determine the tocopherol content. The wound-healing activity was observed on the backs of six adult male rabbits. (3) Results: The results showed that the plant contained fatty acids, as well as oleic (46.05%), palmitic (23.94%), linoleic (11.39%), and stearic (7.87%) acids. The phytosterols were three major compounds; in decreasing order of importance, they were β-sitosterol (97.26 mg/100 g), campesterol (18.94 mg/100 g), and stigmasterol (12.05 mg/100 g). There were also traces of cholesterol. The neem was a moderate source of vitamin E (α-tocopherol, 14.86 mg/100 g). The hexane extracts showed no acute toxicity and low eye and skin irritability and had reasonable safety and important wound-healing activity. (4) Conclusions: The results confirmed that A. indica is a valuable source of fatty acids, phytosterols, and vitamin E and is efficient in the process of wound healing