scholarly journals Triploidy in tambaqui Colossoma macropomum identified by chromosomes of fish larvae

2020 ◽  
Vol 9 (3) ◽  
pp. 65-69
Author(s):  
Diogo Hashimoto
Keyword(s):  
Fish Larvae ◽  
Alternative Methods ◽  
Mitotic Chromosomes ◽  
Neotropical Fish ◽  
Early Puberty ◽  
Colossoma Macropomum ◽  
Heat Shocks ◽  
Negative Impacts ◽  
Conservation Plans ◽  
Rates Of Growth

Triploid fish are excellent models for use in commercial scale because they can show higher rates of growth, carcass yield and meat quality. If sterile, tambaqui (Colosso mamacropomum) triploids can be used to avoid the problems related to early puberty, especially the negative impacts of male sexual maturation on harvest weight. In the present study, we evaluated the triploidy induction efficiency (thermal shocks) in the fish tambaqui Colossoma macropomum, the most important Neotropical species used for aquaculture. To verify the result of the triploidy experiments, we used a protocol of ploidy identification through analysis of mitotic chromosomes of early life stages (larvae cytogenetics). We obtained better results of hatching and triploid rates through temperature shock at 41°C for 2 min (heat shock) than cold shock. In conclusion, additional treatments will allow to refine the protocols to obtain 100% of triploidy in tambaqui, particularly those from heat shocks. These methodologies can also be applied to other Neotropical fish species, as alternative methods for breeding programs and to delineate conservation plans for the proper management of the stocks.

scholarly journals Intentions and Repercussions of Revitalization: Urban Geographical Research Using Walking Methodology

2020 ◽  
Vol 11 (1) ◽  
pp. 13-27
Author(s):  
Lauren Woods
Keyword(s):  
Business Owners ◽  
Alternative Methods ◽  
Emotional Experiences ◽  
Geographical Research ◽  
Racial History ◽  
Negative Impacts

This paper asks readers to consider both the positive and negative impacts of gentrification on residents and business owners. The paper draws from a project that used a walking methodology to explore a neighborhood, in addition to supplemental readings related to various ways of experiencing and knowing, racial history and tensions, and issues surrounding gentrification in other areas. I begin this paper by describing experiences I had as a child, and how those previous experiences colored my perception while walking through an area of town that is now vastly different due to revitalization from my memories from when I was younger. I also explore connections made from reviews of literature related to alternative methods of collecting and exploring data, as well as reflections from sensory and emotional experiences during the walks. This research was contextualized using articles and news clips discussing various viewpoints regarding if the changes in the neighborhood should be called revitalization or gentrification. I then leave it to the reader to question both the positive and negative impacts of gentrification.

Histopathological changes in gill, liver and kidney of neotropical fish Colossoma macropomum exposed to paraquat at different temperatures

2011 ◽  
Vol 31 (3) ◽  
pp. 490-495 ◽  
Author(s):  
Raquel Salazar-Lugo ◽  
Claunis Mata ◽  
Aridays Oliveros ◽  
Luz Marina Rojas ◽  
Mairin Lemus ◽  
...  
Keyword(s):  
Histopathological Changes ◽  
Neotropical Fish ◽  
Colossoma Macropomum ◽  
Different Temperatures ◽  
Liver And Kidney

SNPs markers for the heavily overfished tambaqui Colossoma macropomum, a Neotropical fish, using next-generation sequencing-based de novo genotyping

2016 ◽  
Vol 9 (1) ◽  
pp. 29-33 ◽  
Author(s):  
José Gregorio Martínez ◽  
Valéria Nogueira Machado ◽  
Susana J. Caballero-Gaitán ◽  
Maria da C. Freitas Santos ◽  
Rodrigo Maciel Alencar ◽  
...  
Keyword(s):  
Next Generation Sequencing ◽  
De Novo ◽  
Next Generation ◽  
Neotropical Fish ◽  
Colossoma Macropomum ◽  
Generation Sequencing

scholarly journals Modified Voltage Control Law for Low Frequency Railway Power Systems

2017 ◽  
Author(s):  
John Laury ◽  
Lars Abrahamsson ◽  
Math Bollen
Keyword(s):  
Power Systems ◽  
Reactive Power ◽  
Low Frequency ◽  
Voltage Control ◽  
Load Sharing ◽  
Alternative Methods ◽  
Control Law ◽  
Public Power ◽  
Negative Impacts ◽  
Railway Power Systems

In today’s Swedish and Norwegian low frequency railway power system the voltage at a converter is controlled such that its voltage will drop with increased reactive power output. However, for low frequency railways the influence of active power on voltage is larger compared to public power systems and alternative methods are interesting to investigate. This paper presents a modified voltage control law for increased load sharing between converter stations and reduce the risk for converter overload in low frequency railways power systems. The modified voltage control law is derived mathematically and tested with different droops for two case studies. The results confirms the increased load sharing between the converter stations. The results are analysed and discussed; ideas are presented to counteract some of the negative impacts of the modified voltage control law.

scholarly journals Effect of water temperature and prey concentrations on initial development of Lophiosilurus alexandri Steindachner, 1876 (Siluriformes: Pseudopimelodidae), a freshwater fish

2014 ◽  
Vol 12 (4) ◽  
pp. 853-859 ◽  
Author(s):  
Rodrigo Takata ◽  
Walisson de Souza e Silva ◽  
Deliane Cristina Costa ◽  
Reinaldo Melillo Filho ◽  
Ronald Kennedy Luz
Keyword(s):  
Growth Rate ◽  
Water Temperature ◽  
Specific Growth ◽  
Condition Factor ◽  
Fish Larvae ◽  
Neotropical Fish ◽  
Prey Concentration ◽  
Initial Development ◽  
Nitrogen Incorporation ◽  
Artemia Nauplii

The aim of this study was to investigate the effects of water temperature and prey concentrations (Artemia nauplii) on the initial development of Lophiosilurus alexandri larvae. The experiment was conducted using a 4 x 2 factorial design, with four water temperatures (23, 26, 29 and 32 °C), two different initial prey concentrations (P700 and P1,300) and three replicates. Feeding was increased during the fifteen-day experiment. At the end of the experiment, the survival and condition factor were affected only by prey concentrations, with elevated numbers of Artemia nauplii leading to higher averages of these variables. The total length (TL) and specific growth rate were separately influenced by temperature and prey concentration, without interaction between them, and weight showed an interaction with these factors. In general, an increase of temperature (23 to 32 °C) improved the growth and nitrogen gain in L alexandri larvae. For TL, the optimal temperatures estimated were 31.4 and 31.0 °C for P700 and P1,300, respectively. Similar mean body weight larvae and nitrogen gain were observed at 23 °C for both levels of prey concentrations. For other temperatures, the P1,300 level provided greater weight gain for L. alexandri. Therefore, it is suggested that temperatures between 29-32 °C combined with a higher level of prey concentration maximise the development and nitrogen gain in L. alexandri larvae. Moreover, this is the first result about nitrogen incorporation in neotropical fish larvae.

Branchial receptors and cardiorespiratory reflexes in a neotropical fish, the tambaqui (Colossoma macropomum)

2000 ◽  
Vol 203 (7) ◽  
pp. 1225-1239 ◽  
Author(s):  
L. Sundin ◽  
S.G. Reid ◽  
F.T. Rantin ◽  
W.K. Milsom
Keyword(s):  
Buccal Cavity ◽  
Cranial Nerves ◽  
Breathing Frequency ◽  
Aquatic Surface Respiration ◽  
Neotropical Fish ◽  
Cardiorespiratory Control ◽  
Colossoma Macropomum ◽  
Before And After ◽  
Water Ph ◽  
Ventral Aorta

This study examined the location and physiological roles of branchial chemoreceptors involved in the cardiorespiratory responses to hypoxia and hypercarbia in a neotropical fish that exhibits aquatic surface respiration, the tambaqui (Colossoma macropomum). Fish were exposed to abrupt progressive environmental hypoxia (18. 6–1.3 kPa water P(O2)) and hypercarbia (water equilibrated with 5 % CO(2) in air, which lowered the water pH from 7.0 to 5.0). They were also subjected to injections of NaCN into the ventral aorta (to stimulate receptors monitoring the blood) and buccal cavity (to stimulate receptors monitoring the respiratory water). All tests were performed before and after selective denervation of branchial branches of cranial nerves IX and X to the gill arches. The data suggest that the O(2) receptors eliciting reflex bradycardia and increases in breathing frequency are situated on all gill arches and sense changes in both the blood and respiratory water and that the O(2) receptors triggering the elevation in systemic vascular resistance, breathing amplitude, swelling of the inferior lip and that induce aquatic surface respiration during hypoxia are extrabranchial, although branchial receptors also contribute to the latter two responses. Hypercarbia also produced bradycardia and increases in breathing frequency, as well as hypertension, and, while the data suggest that there may be receptors uniquely sensitive to changes in CO(2)/pH involved in cardiorespiratory control, this is based on quantitative rather than qualitative differences in receptor responses. These data reveal yet another novel combination for the distribution of cardiorespiratory chemoreceptors in fish from which teleologically satisfying trends have yet to emerge.

scholarly journals A review of plant protection against the olive fly (Bactrocera oleae (Rossi, 1790) Gmelin) and molecular methods to monitor the insecticide resistance alleles

2017 ◽  
Vol 109 (1) ◽  
pp. 135 ◽  
Author(s):  
Matjaž Hladnik
Keyword(s):  
Plant Protection ◽  
Molecular Methods ◽  
Bactrocera Oleae ◽  
Alternative Methods ◽  
Current Status ◽  
Mass Trapping ◽  
Protection Measures ◽  
Development Of Resistance ◽  
Olive Fly ◽  
Negative Impacts

<p class="Abstract"><span lang="EN-US">Olive fly (<em>Bactrocera oleae </em>(Rossi, 1790) Gmelin) is one of the most important olive pests worldwide. Most plant protection measures are based on insecticides, especially organophosphates, pyrethroids, and recently a spinosad. Insecticides are used as cover sprays or in more environmentally friendly methods in which insecticides are used in combination with attractants and pheromones as bait sprays or for mass trapping. However, due to negative impacts of insecticides to environment, new plant protection methods are constantly developing with the aim to lower the consumption of insecticides or even to eliminate them by biological control with entomopathogenic organisms, sterile insect technique (SIT), or transgenic method RIDL (release of insects carrying a dominant lethal). However, these methods need to be improved in order to guarantee adequate protection. Alternative methods than those traditionally used are required due to long term usage causing the development of resistance to the insecticides, ultimately lowering their effectiveness. Molecular methods for monitoring the frequencies of resistant alleles and the current status of resistance alleles in olive growing countries are reviewed here.</span></p>

scholarly journals Functional Chitosan Derivative and Chitin as Decolorization Materials for Methylene Blue and Methyl Orange from Aqueous Solution

Materials ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 361 ◽  
Author(s):  
Abdelkader Labidi ◽  
Asier Salaberria ◽  
Susana Fernandes ◽  
Jalel Labidi ◽  
Manef Abderrabba
Keyword(s):  
Aqueous Solution ◽  
Methylene Blue ◽  
Methyl Orange ◽  
Sticking Probability ◽  
Alternative Methods ◽  
Standard Entropy ◽  
Chitosan Derivative ◽  
Thermodynamic Variables ◽  
Negative Impacts ◽  
Chitin And Chitosan

Dyes are classified as one of the major pollutants of water. They have negative impacts not only on environment but also on human health. In fact, wastewater that contains these harmful substances requires many types of treatments. Therefore, alternative methods and adsorption agents are needed. Herein, we propose to evaluate the decolorization of methylene blue (MB) and methyl orange (MO) as two models of soluble dyes from water using chitin and chitosan-graft-polyacrylamide. Furthermore, the applicability of these biomacromolecules as alternative adsorption agents, their sticking probability and desorption were also examined. Experimental parameters such as dye concentration, contact time, pH solution, adsorbent dosage and temperature were thoroughly examined for the grafted chitosan and chitin. The activation energy ( E a ) and the thermodynamic variables (i.e., standard Gibb’s free energy ( Δ G 0 ), standard enthalpy ( Δ H 0 ), and standard entropy ( Δ S 0 )) were determined using the Van’t Hoff and Arrhenius equations. The sticking probability ( S *) model for MB and MO removal by chitin and the chitosan derivative demonstrated that both dyes were successfully removed under the proposed conditions. Desorption studies of MB and MO showed the reusability of both materials, suggesting their application for removing dyes from aqueous solution.

scholarly journals The Possible Biotechnological Use of Edible Mushroom Bioproducts for Controlling Plant and Animal Parasitic Nematodes

2020 ◽  
Vol 2020 ◽  
pp. 1-12 ◽  
Author(s):  
Gloria Sarahi Castañeda-Ramírez ◽  
Juan Felipe de Jesús Torres-Acosta ◽  
José Ernesto Sánchez ◽  
Pedro Mendoza-de-Gives ◽  
Manases González-Cortázar ◽  
...  
Keyword(s):  
Edible Mushroom ◽  
Alternative Methods ◽  
Farm Animals ◽  
Economic Losses ◽  
Parasitic Nematodes ◽  
Plant Parasitic Nematodes ◽  
Livestock Industry ◽  
Nematocidal Activity ◽  
Negative Impacts ◽  
Potential Use

The present paper reviewed publications on the nematocidal activity of edible mushrooms (EM) and their potential use as sustainable tools for the control of parasitic nematodes affecting agriculture and livestock industry. Nematodes are organisms living in the soil and animals’ guts where they may live as parasites severely affecting economically important crops and farm animals, thus causing economic losses to worldwide agriculture. Traditionally, parasitic nematodes have been controlled using commercial pesticides and anthelmintic (AH) drugs. Over the years, nematodes developed resistance to the AH drugs, reducing the usefulness of many commercial drugs. Also, the use of pesticides/anthelmintic drugs to control nematodes can have important negative impacts on the environment. Different EM have been not only used as food but also studied as alternative methods for controlling several diseases including parasitic nematodes. The present paper reviewed publications from the last decades about the nematocidal activity of EM and assessed their potential use as sustainable tools for the control of nematodes affecting agriculture and livestock industry. A reduced number of reports on the effect of EM against nematodes were found, and an even smaller number of reports regarding the potential AH activity of chemical compounds isolated from EM products were found. However, those studies have produced promising results that certainly deserve further investigation. It is concluded that EM, their fractions and extracts, and some compounds contained in them may have biotechnological application for the control of animal and plant parasitic nematodes.

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