The Diverse World of Protists-an Ideal Community with which to Introduce Microscopy in the Microbiology Teaching Laboratory.

Protists and other eukaryotes are present in diverse terrestrial and aquatic environments. They can easily be collected from local ponds and streams. Although they are typically larger in size than prokaryotes, making them easy to study with even basic microscopes, microbiology laboratory courses often do not discuss them in detail and may only dedicate a short time to observing preserved samples.

Fitness Analysis and Transcriptome Profiling Following Repeated Mild Heat Stress of Varying Frequency in Females.

Understanding how repeated stress affects metabolic and physiological functions in the long run is of crucial importance for evaluating anthropogenic pressure on the environment. We investigated fertility, longevity and metabolism in females exposed to short-term heat stress (38 °C, 1 h) repeated daily or weekly. Daily stress was shown to cause a significant decrease in both fertility and longevity, as well as in body mass and triglyceride (fat) content, but a significant increase in trehalose and glucose content.

The effect of mild heat stress of different frequencies on the adaptability of Drosophila melanogaster females.

In natural populations, insects regularly face an adverse impact of different natures: harsh weather swings, lack of food resources, the insecticidal treatment. We studied the effect of repeated episodes of mild heat stress of different frequencies on stress resistance of Drosophila melanogaster females. We found out that the mild heat stress (38°С, 1 hr) repeated daily within 2 weeks resulted in (a) an increased activity of the dopamine (DA) metabolism enzymes, DA-dependent arylalkylamine N-acetyltransferase and alkaline phosphatase, which suggested a decrease in DA level, and (b) an increased survival rate under acute heat stress (38°С, 4 hr).

female fertility and juvenile hormone metabolism depends on the type of infection.

Maternally inherited intracellular bacteria cause both parasitic and mutualistic effects on their numerous insect hosts, including manipulating the host reproductive system in order to increase the bacteria spreading in a host population, and increasing the host fitness. Here, we demonstrate that the type of infection determines the effect on egg production as a proxy for fecundity, and metabolism of juvenile hormone (JH), which acts as gonadotropin in adult insects. For this study, we used six lineages carrying the nuclear background of interbred Bi90 lineage and cytoplasmic backgrounds with or without of different genotype variants.

Poster Development and Presentation to Improve Scientific Inquiry and Broaden Effective Scientific Communication Skills.

We have redesigned a tried-and-true laboratory exercise into an inquiry-based team activity exploring microbial growth control, and implemented this activity as the basis for preparing a scientific poster in a large, multi-section laboratory course. Spanning most of the semester, this project culminates in a poster presentation of data generated from a student-designed experiment. Students use and apply the scientific method and improve written and verbal communication skills.

Various Wolbachia genotypes differently influence host Drosophila dopamine metabolism and survival under heat stress conditions.

Background: One of the most widespread prokaryotic symbionts of invertebrates is the intracellular bacteria of Wolbachia genus which can be found in about 50% of insect species. Wolbachia causes both parasitic and mutualistic effects on its host that include manipulating the host reproductive systems in order to increase their transmission through the female germline, and increasing the host fitness. One of the mechanisms, promoting adaptation in biological organisms, is a non-specific neuroendocrine stress reaction.

The role of insulin signalling in the endocrine stress response in Drosophila melanogaster: A mini-review.

The endocrine stress response in Drosophila includes catecholamines, juvenile hormone (JH), 20-hydroxyecdysone (20E) and the insulin/insulin-like growth factor signalling pathway (IIS). Several changes in the IIS and hormonal status that occur under unfavourable conditions are universal and do not depend on the nature of stress exposure. The reviewed studies on the impact of different element of the Drosophila IIS, such as insulin-like receptor, the homologue of its substrate, CHICO, the transcription factor dFOXO and insulin like peptide 6, on the hormonal status suggest that the IIS controls catecholamine metabolism indirectly via JH, and there is a feedback loop in the interaction of JH and IIS.

Insulin-like peptide DILP6 regulates juvenile hormone and dopamine metabolism in Drosophila females.

Insulin-like peptide DILP6 is a component of the insulin/insulin-like growth factor signalling pathway of Drosophila. Juvenile hormone (JH) and dopamine (DA) are involved in the stress response and in the control of reproduction. In this study, we investigate whether DILP6 regulates the JH and DA levels by studying the effect of a strong hypomorphic mutation dilp6 on JH and DA metabolism in D.

The impact of FOXO on dopamine and octopamine metabolism in Drosophila under normal and heat stress conditions.

The forkhead boxO transcription factor (FOXO) is a component of the insulin signalling pathway and plays a role in responding to adverse conditions, such as oxidative stress and starvation. In stressful conditions, FOXO moves from the cytosol to the nucleus where it activates gene expression programmes. Here, we show that FOXO in Drosophila melanogaster responds to heat stress as it does to other stressors.

The insulin-like receptor gene expression in the tissues synthesizing gonadotropic hormones at sexual maturation of Drosophila melanogaster females].

The insulin/insulin-like growth factor signaling pathway is involved in the regulation of the synthesis of insect gonadotropic hormones, juvenile (JH) and 20-hydroxyecdysone (20E). We carried out the immunohistochemical analysis of the insulin receptor (InR) expression in the corpus allatum (the JH-producing gland) and in the ovarian follicular cells (a site for the synthesis of 20E precursor, ecdysone) in the process of sexual maturation of D. melanogaster females and examined the influence of exogenous JH on the InR expression in these tissues.

Mutation in the Drosophila insulin-like receptor substrate, chico, affects the neuroendocrine stress-reaction development.

It is shown for the first time that the insulin receptor substrate gene chico controls the functioning of the systems of metabolism of dopamine and juvenile hormone in Drosophila melanogaster females under normal conditions and in thermal stress.

[Gene dilp6 regulates octopamine metabolism in Drosophila melanogaster].

The effect of strong hypomorphic mutation of the insulin-like protein gene (dilp6) on metabolism of octopamine (one of the main biogenic amines in insects) was studied in Drosophila melanogaster males and females. The activity of tyrosine decarboxylase (the key enzyme of octopamine synthesis) and the activity of octopamine-dependent N-acetyltransferase (the enzyme of its degradation) were measured. It was demonstrated that the activity of both studied enzymes is decreased under normal conditions in the dilp6 41 mutants (as we previously demonstrated, this is correlated with an increased level of octopamine).

[dFOXO Transcription Factor Regulates Juvenile Hormone Metabolism in Drosophila melanogaster Females].

dFOXO transcription factor is a component of the insulin/insulin-like growth factor signaling pathway in Drosophila. Juvenile hormone negatively regulates dFOXO gene expression. In the present work, the effect of hypomorphic dFOXO mutation on juvenile hormone metabolism under normal and stressing conditions and on D.

[Knockdown of InR gene in ventral nephrocytes promotes resistance to toxic stress in Drosophila melanogaster females].

Hemolymph filtration in insects is performed by nephrocytes, additional cells of the circulatory system that are not connected to Malpighian vessels. Drosophila has two types of nephrocytes: the ventral ("garland"), which are situated around the connection site of the esophagus and proventriculus, and the pericardial, which are localized around the heart. In this study, we examined the role of the of insulin-like receptor (InR)gene in regulation of the function of ventral nephrocytes (VNC) in D.

[P-M hybrid dysgenesis affects juvenile hormone metabolism in Drosophila melanogaster females].

This paper studies the metabolism of the juvenile hormone, which affects gonads functioning in Drosophila melanogasterfemales under P-M hybrid dysgenesis. It is shown that dysgenic females grown at 29°C have increased levels of the juvenile hormone (its degradation and stress reactivity are reduced), which apparently is a compensatory response to ovarian hypoplasia.

[InR gene expression and octopamine metabolism in Drosophila melanogaster females].

The influence of suppression of the expression of the Drosophila insulin-like receptor gene (InR) in corpus allatum (the gland-synthesizing juvenile hormone) on octopamine and juvenile hormone metabolism and on the development of the stress-reaction in Drosophila melanogaster females was studied. It was demonstrated that the suppression of InR gene expression in corpus allatum induces in D. melanogaster females an increase in the activity of the enzyme that limits the rate of octopamine synthesis (tyrosine decarboxylase), as well as in the level of juvenile hormone degradation and the intensity of the response of octopamine and juvenile hormone metabolism systems to heat stress.

Selenate reductase activity in Escherichia coli requires Isc iron-sulfur cluster biosynthesis genes.

The selenate reductase in Escherichia coli is a multi-subunit enzyme predicted to bind Fe-S clusters. In this study, we examined the iron-sulfur cluster biosynthesis genes that are required for selenate reductase activity. Mutants devoid of either the iscU or hscB gene in the Isc iron-sulfur cluster biosynthesis pathway lost the ability to reduce selenate.

Disruption of insulin signalling affects the neuroendocrine stress reaction in Drosophila females.

Juvenile hormone (JH) and dopamine are involved in the stress response in insects. The insulin/insulin-like growth factor signalling pathway has also recently been found to be involved in the regulation of various processes, including stress tolerance. However, the relationships between the JH, dopamine and insulin signalling pathways remain unclear.

Seleniivibrio woodruffii gen. nov., sp. nov., a selenate- and arsenate-respiring bacterium in the Deferribacteraceae.

A Gram-type-negative, obligately anaerobic, selenate-respiring bacterium, strain S4(T), was isolated from activated sludge of a wastewater treatment plant in New Jersey after enrichment with 10 mM selenate as the sole electron acceptor. In addition to its selenate-respiring capability, strain S4(T) also respired arsenate with acetate as carbon source and electron donor. Fermentative growth was not observed.