Tilapia Lake Virus-Induced Neuroinflammation in Zebrafish: Microglia Activation and Sickness Behavior

In mammals, the relationship between the immune system and behavior is widely studied. In fish, however, the knowledge concerning the brain immune response and behavioral changes during brain viral infection is very limited. To further investigate this subject, we used the model of tilapia lake virus (TiLV) infection of zebrafish (Danio rerio), which was previously developed in our laboratory. We demonstrated that TiLV persists in the brain of adult zebrafish for at least 90 days, even when the virus is not detectable in other peripheral organs. The virions were found in the whole brain. During TiLV infection, zebrafish displayed a clear sickness behavior: decreased locomotor activity, reduced food intake, and primarily localizes near the bottom zone of aquaria. Moreover, during swimming, individual fish exhibited also unusual spiral movement patterns. Gene expression study revealed that TiLV induces in the brain of adult fish strong antiviral and inflammatory response and upregulates expression of genes encoding microglia/macrophage markers. Finally, using zebrafish larvae, we showed that TiLV infection induces histopathological abnormalities in the brain and causes activation of the microglia which is manifested by changes in cell shape from a resting ramified state in mock-infected to a highly ameboid active state in TiLV-infected larvae. This is the first study presenting a comprehensive analysis of the brain immune response associated with microglia activation and subsequent sickness behavior during systemic viral infection in zebrafish.

Sulfidogenic Microbial Communities of the Uzen High-Temperature Oil Field in Kazakhstan

Application of seawater for secondary oil recovery stimulates the development of sulfidogenic bacteria in the oil field leading to microbially influenced corrosion of steel equipment, oil souring, and environmental issues. The aim of this work was to investigate potential sulfide producers in the high-temperature Uzen oil field (Republic of Kazakhstan) exploited with seawater flooding and the possibility of suppressing growth of sulfidogens in both planktonic and biofilm forms. Approaches used in the study included 16S rRNA and dsrAB gene sequencing, scanning electron microscopy, and culture-based techniques. Thermophilic hydrogenotrophic methanogens of the genus Methanothermococcus (phylum Euryarchaeota) predominated in water from the zone not affected by seawater flooding. Methanogens were accompanied by fermentative bacteria of the genera Thermovirga, Defliviitoga, Geotoga, and Thermosipho (phylum Thermotogae), which are potential thiosulfate- or/and sulfur-reducers. In the sulfate- and sulfide-rich formation water, the share of Desulfonauticus sulfate-reducing bacteria (SRB) increased. Thermodesulforhabdus, Thermodesulfobacterium, Desulfotomaculum, Desulfovibrio, and Desulfoglaeba were also detected. Mesophilic denitrifying bacteria of the genera Marinobacter, Halomonas, and Pelobacter inhabited the near-bottom zone of injection wells. Nitrate did not suppress sulfidogenesis in mesophilic enrichments because denitrifiers reduced nitrate to dinitrogen; however, thermophilic denitrifiers produced nitrite, an inhibitor of SRB. Enrichments and a pure culture Desulfovibrio alaskensis Kaz19 formed biofilms highly resistant to biocides. Our results suggest that seawater injection and temperature of the environment determine the composition and functional activity of prokaryotes in the Uzen oil field.

Administration of Quercetin Ameliorates Lipopolysaccharide Induced Neuroinflammation and Oxidative Stress in Adult Zebrafish

Background: Quercetin is a natural flavonoid which is known to have numerous pharmacological activities such as antioxidative, anti-inflammatory and neuroprotective effects against various neurological disorders. Lipopolysaccharide (LPS) is a potent endotoxin, reported to cause various neurological disorders such as Alzheimer’s Disease (AD), Parkinson’s Disease (PD), Multiple Sclerosis (MS), Amyotrophic Lateral Sclerosis (ALS), Stroke (Brain Attack), Meningitis. Aim: The present study was designed to investigate the possibility thatquercetin ameliorates LPS induced oxidative stress and neuroinflammation in adult zebrafish. Materials and methods: Zebrafish (weighing 470-530 mg) were treated with single injection of LPS (1 mg/kg) intraperitoneally (i.p.) followed by post treatment for 7 days with quercetin (50 and 100 mg/kg; i.p.). After sacrificed, brain was harvested and subjected for biochemical, molecular and histological analyses. Results: Results revealed post treatment with quercetin was able to ameliorate the behavioral abnormalities as in novel diving test- time spent in top zone (TSTZ), and number of entries in top zone was significantly more as compared to time spent in bottom zone (TSBZ). In light-dark chamber test- time spent in light zone (TSLZ), and number of entries in light zone was significantly more as compared to time spent in dark compartment (TSDC). Additionally, results of histopathology (H & E stain) studies showed less disruption in neuronal cells as compared to LPS treated group. Moreover, results of molecular analysis implies that quercetin treatment significantly decrease TNF-α and IL-1β level as compared to LPS treated animals. Further, results of biochemical analysis reveal that quercetin reduce the level of LPO, nitrite, AChEs and increases anti-oxidant GSH. Conclusion: Quercetin treatment helps to prevent oxidative damage and neuroinflammation in LPS treated adult zebrafish.

Performance Analysis of Hydrocarbon Wells Based on the Skin Zone

The purpose of this research is to study the area near the bottom of the hydrocarbon well, which is usually affected by drilling and development operations, and to find a modern method that improves the transfer of fluid from the reservoir to the well.The area near the wellbore of an oil and gas formation is a very active and unstable zone. Field studies have shown that during the process of drilling the first well into the pay zone, a new area of disturbed permeability and porosity forms around the wellbore. This disturbed area is called the skin zone and is characterized by different properties. The skin zone can also form during the completion processes of hydrocarbon wells.In terms of well test processing for any hydrocarbon well, the term "skin effect" should be understood as the effect of changes in the lower wellbore zone (i.e., changes in rock properties, changes in formation fluid, formation structure, geologic section, etc.) on bottom wellbore pressure. This indicates a change in the permeability of the bottom zone of the borehole during drilling and development.In this paper, a new computational method is proposed in which the investigation of hydrocarbon well condition can be performed in two ways. The first way represents replacing the true radius of the wellbore (rw) with an effective radius (rwe). Under this condition, the skin factor term reflects only the effect of changes in the bottom wellbore zone. The second way is that the skin factor indicates not only the amount of change in the bottom wellbore zone, but also the effect of hydrodynamic imperfection of the hydrocarbon well performance during production, while maintaining the value of the well radius. After evaluating these parameters, it is possible to conclude the effectiveness of the implemented measures in the bottom wellbore zone of the formation. At the same time, the value of the skin factor after the performed works regarding the impact on the bottom zone can determine the positive or negative impact on the operation of the hydrocarbon well.

Stress-Deformed State of the Breed in the Funnel of Depression

Analytical solutions of one-dimensional equations of poroelasticity, describing the stress distribution in the depression (repression) funnel, are obtained in this work. It is shown that the influence of the boundary conditions on the wellbore wall is significant only in a relatively small (~1 m) vicinity of the wellbore bottom zone. It has been established also that in fractured rocks in cased wells, the compressive angular stresses, which largely determine the filtration conductivity of the bottomhole zones, will be less than in uncased wells. A method is described that makes it possible to increase the tightness of preserved wells in depleted fields. The method consists in cutting out a section of the casing pipe above the productive formation, expanding the wellbore in this section, installing a spring metal centralizer in this section, followed by cementing it. The formation of such a rigid element associated with the casing will prevent rock displacement relative to this pipe and ensure the tightness of the near-wellbore zone of the well.

Proposal for Water Quality Improvement by Using an Innovative and Comprehensive Restoration Method

This study was conducted on Miłkowskie Lake (23.7 ha; 15.0 m) in the context of implementing new restoration methods for improving the water quality. The study found that the nutrient loads introduced into the lake from catchment are higher than the critical concentrations for the ecosystem. This indicates the need to cut off or at least reduce the main sources of pollution. The primary production in the lake is extremely large: oxygen saturation of the surface water above 200%, pH value of 9.44, chlorophyll a content of 70.98 mg m−3, and a low visibility of 0.5 m. The most important step in maintaining good lake quality will be to redirect waters of the main inflows SI-1 and SI-2 to the hypolimnion zone by pipelines. A complementary method for discharging the polluted water to the hypolimnion zone will be the phosphorus inactivation method by using iron and aluminum coagulants. After the application of spring doses of coagulants, an anti-cyanobacterial preparation will be introduced into the water in the “active bottom” zone, and then bioremediation by a microbiological probiotic preparation will be applied to the sediment in the same zone. A new complex protection and restoration method should be supported in the form of biomanipulation.

The Effects of Limiting Restoration Treatments in a Shallow Urban Lake

Swarzędzkie Lake, directly polluted for many years with municipal wastewater and heavily loaded with nutrient compounds from the catchment area, has become degraded and strongly eutrophicated. Strong cyanobacterial blooms have contributed, among others, to the cessation of recreational use of this urban lake. Its sustainable restoration was started in autumn 2011. These treatments were a combination of three complementary methods: aeration with a pulverizing aerator, phosphorus inactivation with small doses of magnesium chloride and iron sulphate (<15 kg ha−1) and biomanipulation. These treatments were carried out for three years (2012–2014), and in the next two (2015–2016), treatments were limited from three to one method—aeration. The obtained effects (a decrease in the number of cyanobacteria in phytoplankton and at the same time an increase in its biodiversity, decrease in chlorophyll a concentration and improvement of transparency) were lost due to the cessation of phosphorus inactivation and biomanipulation. The biological balance was upset, which resulted in an increase in chlorophyll a concentration, the return of cyanobacteria dominance in the phytoplankton and a deterioration of water quality. Leaving only a pulverizing aerator active, to maintain low oxygen concentrations near the bottom zone was not sufficient to ensure a gradual improvement of water quality with quite a significant external load of nutrients.