Tips for choosing a laboratory or mentor

During the student stage, the most critical thing is to make an informed decision when choosing the research laboratory to develop your career, so you can enjoy doing science. According to a publication made by HOT, you must cover the following aspects:

Know yourself: by asking yourself self-reflective questions, the research environment should go with your lifestyle and personality. Select a tutor who is a good scientist and a good mentor: if your main researcher (IP) is not a good scientist or does not know how to become one, it will be more difficult for you to be one of them! The way your IP addresses challenges and opportunities will be the way in which you will manage your independent laboratory. Your tutor must have good research qualities and as a mentor! This to guide you as a person, share your experience and support you throughout your long-term development. Select a research environment that is right for you. Where you feel comfortable with your research group and cover your needs. Select a research project that makes you interesting. That motivates you and allows you to develop new skills. Try to be a Pioneer in new areas! Track for current positions. In case you are interested in being part of the academy. Be alert for possible warnings. For example, excessive overlap between projects, depressed people, members who do not respect the IP, etc.

• Reference: HOT newsletter june- jul 2016 (page 10).

Predoctoral examination presentation (ORAL)

Access to scientific and technological information resources CONRICYT

If you are a student in an institution in Mexico, you have FREE access to the resources of the page of the CONRICYT.

You will have to request your access and in case it does not reach you, do not forget to contact the administrators of the page, who will help you to register.

Once you are registered, you can search books, magazines and other publications for free, provided they are registered on the CONRICYT page:

Acclimatization to pollution, adaptation, resistance and tolerance in ecotoxicology

Acclimation, adaptation, resistance or tolerance can be defined as the capacity of organisms to cope with stress, either natural changes in temperature, salinity, dissolved oxygen and toxins or chemicals depending on anthropogenic sources.

Defense mechanisms: physiological responses to chemical stress (biomarkers)

• Types of biological response:
• Changes at the molecular level (genetic integrity, biochemical responses)
• Changes at the physiological or organ level (histopathological disturbances, immunotoxicological changes)
• Changes at the population or community level (dynamics, structure)

The effects of environmental stressors start from the effects (biomarkers) to lower levels (individual, subindividual). In individuals exposed to chemical compounds (heavy metals, organic pollutants) there may be increases in biochemical biomarkers (metalotein induction, biotransformation metabolism, oxidative stress). However, when acute or chronic chemical stress exceeds compensation limits, biomarker responses are depleted and may decrease below control levels.

Ecological and ecophysiological aspects of tolerance

In a biological community exposed to toxics in a polluted environment, the most sensitive organisms are lost as a result of contaminating pressure, while the most tolerant survive. Consequently, the new community is more tolerant to the toxics responsible for the selection than another originally identical community, but has never been exposed to the toxicant.


Physiologically, the ability to tolerate increased levels of toxic substances can be expensive in terms of energy or other resources. The energy costs are due to processes that protect organisms against stressors (escape reactions, mucous barriers, protein synthesis) or contribute to eliminate the body of a stressor (metabolizing or excreting pollutants).

According to the metabolic cost hypothesis, a decrease in energy reserves (carbohydrates, lipids, proteins) is observed in different species exposed to various types of contaminants. The intensity of the impact of the stressor varies according to the species and type of stressors, due to the effect it has on different biological characteristics.

However, the adaptive benefit of tolerance has another negative counterpart to the potential cost of tolerance that leaves a system deficient to respond to additional stressors.

Referencia: Férard y Blaise (2013). Encyclopedia of Aquatic Ecotoxicology.

Aquatic biomarkers

Biomarker:

It is defined as an observable and / or measurable change in a biological or biochemical response, which ranges from the molecular level to the physiological level and includes behavioral changes.
The responses of the biomarkers indicate any exposure or toxic effect of environmental stressors and should be ecologically relevant.
They are considered as early warning systems in the evaluation of ecosystem quality. They can be used to evaluate the chemical exposure and the adverse effects of contaminants on biota in situ.
These are measured at the individual level but their responses are significant to be predictors of effects at the population level.


Biomarkers of ecotoxicological relevance:

Although individual and subindividual biomarkers are important sensitive tools for assessing the health of organisms, there is a lack of ecological relevance. To improve the ecological risk assessment, higher levels of biological organization (population) are used in the following ecologically relevant biomarkers:

• Behavior
• Reproduction
• Increase
• Energetic metabolism
• Integrity in lysosomes
• Immunotoxicity
• Genotoxicity

Referencia: Férard y Blaise (2013). Encyclopedia of Aquatic Ecotoxicology.

Extrapolation

For a better evaluation of the environmental risk of the chemicals, it is necessary to make a better integration of the ecological theory in the aquatic ecotoxicology, starting from the ecology of communities, trophic interaction and disturbance in ecology (Schmitt-Jansen et al 2008).

For a higher level of biological complexity, the authors introduce the concepts of:

• Sensitivity distribution in species
• Induced tolerance of the community in pollution
• Use of model ecosystems
• Sediment quality
• Landscape ecology

In agreement Schmitt-Jansen et al. (2008), a good water quality is fundamental for a sustainable development of the human society for the water supply, recreational purposes or the maintenance of the biodiversity of the ecosystem. Unfortunately, in many industrialized and agricultural regions pollution of surface and underground water bodies has been a serious problem (Schwarenbach et al., 2006). Despite political efforts to regulate ecological and environmental risk (WFD, EC 2000) or REACH, other aspects of various disciplines are needed, beyond standard toxicity tests. There are almost no approaches based on community indexes with respect to toxics, when evaluating the ecological status of a site.

The authors propose an integrated approach based on the union of basic and applied ecology approaches, aquatic ecotoxicology, ecology of stress and landscape ecology, which take into account the following:

• Laboratory test protocols
• Experimental and field monitoring
• Include early warning systems and computer simulation models
• Information on life cycle characteristics and trophic position of trophic chain species

In agreement Schmitt-Jansen et al. (2008), the union of these aspects could improve ecological realism in the evaluation of chemicals in aquatic ecosystems and be a worthwhile frontier for ecological research with implications for policy and legislation.

Referencia: Schmitt-Jansen M, U Veit, G Dudel y R Altenburger (2008). An ecological perspective in aquatic ecotoxicology: approaches and challenges. Basic and applied ecology 9(4): 337-345.

Endocrine Disruptors

Recently, a review article by Giulivo et al (2016) has been published in Environmental Research, which discusses human exposure to endocrine disruptors and their role in their highest risk targets, such as organs or systems:

• Reproductive systems
• Metabolic system (obesity, diabetes)
• Breast, testicular and ovarian cancer

According to these authors, endocrine disruptors (bisphenol A, phthalates, parabens, etc.) are released into the environment through different sources:

• Packaging industry
• Pesticides
• Food constituents

Giulivo et al (2016) en la Environmental Research 

Zebrafish structure tanks

This video is an interview with the biologist Eric Herbst, responsible for systems design and engineering of the company PENTAIR AQUATIC ECOSYSTEMS.

The tanks that the video presents are used for zebrafish, very used for research with small organisms, as well as others such as medaka or frogs. These have been specifically designed by the PENTAIR company since the 90s.

System characteristics (summary):

• Components of the tanks: tank, lid and baffle in the back.
• Tank material: injection molded, made of polycarbonate and are highly biocompatible, durable, can be disinfected, autoclaved or placed at 180 ° C in boiling water.
• Tank sizes: 1.5, 3 and 10 L.
• Shelf: designed with different configurations according to the size of the tanks.
• Base of the tanks: designed to be put on the shelf.
• Densities of zebrafish per tank: 5-10 adults per liter.
• Characteristics of the tanks: self cleaning that is achieved by the baffle in the rear of the tank and the slope of the front, so that: the water enters the slope and deflects towards the back by the bottom where at the base of the baffle there is a small opening for all the solids to flow below the opening and then a channel on the back of the baffle automatically comes out of the overflow of the gutter.
• Blue color: to ensure the position of zebrafish and minimize algae growth.
• Lid: has four holes in the lid for feeding.
• Division of the tank: it can be divided into two parts at once with an optional separation.
• Baby Baffles: in different colors (yellow, green or blue), according to larval size of the fish.
• Rearing tanks: can be attached to tanks and with special holes for the egg to pass through.
• Networks: size of the network according to the size of the tank to capture all the fish at the same time.

Aquatic Ecotoxicology Book

Aquatic Ecotoxicology: Advancing Tools for Dealing with Emerging Risks

Academic Press; Edición: 1 (11 de junio de 2015)

This book stands out for the following:

• Recent perspectives on emerging toxic risks in aquatic environments, such as: nanomaterials, pharmaceuticals, chemical mixtures
• Practical guide on recent advances to help in choosing the most appropriate toxicological test
• Case studies and information in various species to help put theory into practice risk assessment

Aquatic Habitats System

Aquatic Habitats System Overview / Resumen del sistema Aquatic Habitats ...

This video shows a system for the production of aquatic organisms, such as zebrafish.

This system stands out because it presents the greatest advantage in the handling of containers with different volumes of water from 1.5 L to 30 L approximately, in a smaller space used inside the laboratory.

The system includes different phases such as biological filtering, handling of different temperatures, luminosities, which ensure the good quality of the water required for toxicological tests.