Incomplete detonation of nitrogen-based explosives can lead to abundant levels of nitrate in mine groundwater. The possibility of reducing nitrogen levels from the wastewater through denitrification, anammox and DNRA has been investigated using a full-scale bioreactor. The bioreactor is situated subsurface and is filled with pine woodchips. Groundwater is pumped to the bioreactor and subsequently discharged to a drainage ditch. In this thesis the distribution of the microbial community was determined using quantification of functional genes representing a specific functional community. The 16S rRNA gene was used as proxy for the total bacterial community, nirS and nirK for nitrite reduction, nosZI and nosZII genes for nitrous oxide reduction, nrfA for DNRA, and hdh for anammox reaction. Denitrification appeared as the main nitrogen-reducing process in the bioreactor due to more abundant levels of functional genes. The abundance of nitrous oxide reductase was higher than nitrite oxide, indicating good nitrouse oxide reduction. Anammox could not be detected and DNRA was suggested in the end of the bioreactor due to a decrease in nitrate concentration. The distribution of abundances was not affected by the depth or the time which samples were collected. However, abundances collected at different lengths of the bioreactor showed significant differences for 16S rRNA and the functional genes nirS, nosZI and nrfA. This suggests changing environmental conditions along the bioreactor length. Creating an assay for quantification of sulphate reducing bacteria was also investigated. This was not achieved and the size and distribution of the sulphate reducing community remains to investigate. The bioreactor in the present study can reduce nitrogen from mining water but further analysis are needed in order to understand long-term temporal changes.

No description available.

Salmonella is a common food-borne, intracellular pathogen that causes infections in animals and humans. During infection of the host, flagella serve as important virulence factors that enable the bacterium to reach the site of infection and adhere to the host-cell. Flagella are complex organelles, and their expression is organized by an intricate, regulatory network, governed by the transcription factor FlhDC. While the transcriptional regulation of flagellar genes in Salmonellais well described, there is little known about post-transcriptional mechanisms. The RNA binding protein ProQ was found to promote motility, but the molecular mode of action remained unclear. Recently, the small RNA FlgO was found to be a contributing genetic factor for ProQ-dependent flagellar gene expression. FlgO was hypothesized to base-pair with the 5’untranslated region of the flhDC mRNA and thereby promote translation of the mRNA. As ProQ was positively affecting FlgO steady-state levels, I hypothesized that ProQ stabilizes or aids in processing of FlgO. Further, I investigated the effect of FlgO on translation of the flhDC mRNA. The results of this work showed that the stability and processing of FlgO is independent of ProQ, and in vitro binding assays showed no binding of ProQ to FlgO. However, the RNA binding protein Hfq was found to bind and stabilize FlgO. Further, I found that overexpression of FlgO increases flhDC mRNA translation and that this effect is independent of the small RNAs ArcZ, OmrA/B and OxyS, all of which are known to repress flhDC translation. The precise molecular mechanism of how FlgO stimulates translation of flhDCremains subject for future work.

Amyloid precursor protein beta (βAPP) plays an important role in the pathogenesis of Alzheimer’s disease. An appb mutant strain of zebrafish has been previously generated and has shown increased boldness. Here we tested boldness by Novel Tank Diving Test and compared the results between the wildtype AB strain controls (WT) (N=16) and appb mutant strain (N=28), as well as between two Swedish testing institutions that use different protocols. Fish were tracked by automated video tracking in Ethovision. Compared with the wild type fish, using both the Uppsala and Gothenburg protocols, the mutant fish have a higher cumulative duration in the top area suggesting increased boldness. Greater boldness in mutants appears specifically context dependent and only expressed when the test fish is taken from a larger group of fish.

No description available.

Globally, the cases of cancer have been on the rise. This has led to increasing research to find a lasting solution to carcinogenesis. The increase in cancer cases can be due to a change in people’s lifestyles, such as diet and exercise routines which have changed for the worse. In most farms, chemicals as pesticides are added to plants to fasten their growth. These chemicals are carcinogenic, contributing to the increased number of cancer cases worldwide. The objective of this research was to observe the cell response of brain, pancreatic, and breast cancer cells to different cortisol levels/concentrations. The three cell lines of interest in this research and present in the mentioned types of cancer are T-47D, PANC-1, and T98G. Their dynamics and roles are identified in this study. Cortisol excretion concentrations during stress and cancer growth are also monitored and compared. Additionally, the study solves the unpredictability of the impacts of stress on the three cancer types. The three experimental setups in this study were as follows: 1. Breast cancer cells, obtained from a 54 year old woman with metastatic carcinoma. 2. Brain cancer cells, obtained from a 61 year old female with neuroblastoma. 3. Pancreatic cancer cells, obtained from a 56 year old male with metastatic carcinoma. The cells in the above setups were treated with cortisol in order to see what effect this induced stress has on cell growth. The findings of the study concluded higher cortisol concentration increased cancer growth and spread within the body. This was that all three cancer cell types saw an increased effect of cortisol at either 24 hours or 48 hours at a specific concentration, which highlights that cortisol has an important role to play in cancer cells viability.

No description available.

Arsenic is a toxic metalloid existing everywhere in the nature. It is toxic to most organisms and considered as human carcinogen. Arsenic contamination leads to severe health problems with diseases like damage of skin, lung, bladder, liver and kidney as well as central nervous system. As arsenic can be found everywhere in nature it may come in contact with food chain very easily through either water or cultivated crops. My thesis works include studies of bioremediation of arsenic by microorganisms. In this experiment the test organisms were collected from the Hazaribagh tanning industrial area of Dhaka, Bangladesh. The whole laboratory works were performed with two types of bacterial strains. Genomic DNA isolation and restriction digestion of genomic DNA, plasmid DNA isolation, Growth response to different concentrations of Arsenic, minimum inhibitory concentration (MIC), plasmid degradation procedures were carried out during this experiment. The MIC value for amoxicillin of these test organisms was 300 μg/ml and they are able to degrade 5 mM arsenite (AsIII) and 40 mM arsenate (AsV). Though the experiment was carried out with two bacterial strains but by observing all experimental data such as restriction digestion, growth response to the arsenic before and after treated with ethidium bromide and minimum inhibitory concentration it can be concluded that these two strains were not different. These bacteria are able to survive in high concentration of antibiotics and arsenic (AsV and AsIII). Loss of plasmid resulted no growth on media containing arsenic. These results support that plasmid contains important genes that are responsible for surviving bacteria in stress conditions.

The airborne pathogen Mycobacterium tuberculosis (Mtb) is the causative agent of tuberculosis (TB) and claims about 1.6 million deaths annually (WHO, 2022). TB is transmitted by inhalation when a person with active pulmonary TB produces aerosols, by coughing or other respiratory maneuvers, containing viable Mtb, and a contact inhales these particles. Aerosolized Mtb released by the source case must first survive in air before it can be inhaled by a contact person. The length of time that Mtb can stay viable in air is therefore important for its transmission. While airborne, Mtb is faced with dehydration stress, which is affected mainly by ambient humidity and temperature. However, the longevity of Mtb in aerosols under set environmental conditions has not yet been investigated. Here, the H37Rv laboratory strain of Mtb was aerosolized with a Collison-type nebulizer (CH Technologies, USA) inside a tailored, airtight chamber. The chamber was set at defined conditions of relative humidity (RH) and temperature. At 0, 8 and 30 minutes after aerosolization, Mtb aerosols in the chamber were collected for 10 min using a 6-stage Andersen cascade impactor (TISCH Environmental, USA). Colony-forming units (CFUs) of Mtb from aerosol samples were determined by culture on mycobacterial-selective 7H11 agar 3 weeks later. Culturability of Mtb aerosols at 40% RH and temperatures ranging from 22 to 26 °C (low absolute humidity [AH]) was variable, with 57% of aerosol collections resulting in positive regrowth on agar. In contrast, culturability of aerosolized Mtb was 100% when experiments were performed at 60% RH, 22 °C  or 60% RH, 26 °C. Recovery of Mtb H37Rv at low AH decreased over time, with a trend of approximately 1 log reduction in CFUs from 0 to 30 min. At middle and high AH, reduction in CFUs between 0 and 30 min of aging was only 0.5 and 0.61 log, respectively. The results shown in this work are first-of-a-kind experiments with aerosolized Mtb and they suggest that its survivability and longevity in aerosols improves in higher humidity settings.  This work aims to shine light on the knowledge gaps of Mtb transmission by studying the conditions under which the bacteria survive the best and longest in the air, increasing its chances of finding a new host. Our work suggests that higher humidity, which is common in many TB endemic countries, favor Mtb survival in aerosols. Conditions of higher indoor humidity, which reach 15 g/m3 AH in endemic countries, may thus present an increased risk for TB transmission when sharing air with persons having active pulmonary TB.  Understanding pathogens, their mode of transmission and the determinants of epidemiological success plays a central role in developing effective tools for containment and the long-term goal of disease eradication.

No description available.