Algumas espécies de morcegos têm sido reconhecidas como reservatórios naturais de várias famílias virais, desempenhando um importante papel na trasmissão e manutenção desses micro organismos. Devido à descaracterização e fragmentação de habitats naturais, esses mamíferos buscam alternativas de abrigo e alimento, e assim, ficam cada vez mais expostos aos meios antrópicos e em contato com humanos e animais domésticos. Com exceção do vírus rábico, existem poucos trabalhos realizados na detecção de vírus em morcegos no Brasil. Em virtude disso, o presente estudo objetivou a detecção de vírus (circovírus, astrovírus, coronavírus e lyssavírus relacionados ao vírus da raiva) em amostras de órgãos de morcegos do estado do Rio Grande do Sul. Os ácidos nucléicos foram extraídos das amostras de órgãos de morcegos e submetidos à detecão por PCR e RT-PCR. Após a detecção, os fragmentos obtidos foram sequenciados para realizar análise filogenética dos vírus encontrados. Ao total foram analisadas 108 amostras de diferentes espécies e localidades, das quais dez foram positivas para circovírus, seis para coronavírus e 25 para astrovírus, este último sendo o primeiro registro do vírus em morcegos para o Brasil. Todas as amostras foram negativas para lyssavírus relacionados ao vírus da raiva. Análises filogenéticas revelaram que as sequências de circovírus agruparam em ambos os gêneros Circovirus e Cyclovirus, coronavírus no gênero Alphacoronavirus em dois clados diferentes e astrovírus no gênero Mamastrovirus junto com outros astrovírus de morcegos, o qual formam um clado separado dos outros mamíferos. Os resultados demonstram uma diversidade genética entre os vírus encontrados em diferentes espécies de morcegos, que possuem dietas alimentares e habitats distintos. / Some bat species have been recognized as natural reservoirs of several viral families, playing an important role in the transmission and maintaining of these micoorganism. Due to mischaracterization and fragmentation of natural habitats, these mammals seek shelter alternatives and food, and thus are increasingly exposed to anthropism, which make the contact with humans and domestic animals closer. With the exception of the rabies virus, there are few studies on the detection of viruses in bats in Brazil. Therefore, the present study aimed the detection of viruses (circovirus, astrovirus, coronavirus and rabies-related virus) in bats organs samples from Rio Grande do Sul state. Nucleic acids were extracted from bat organs samples and submitted to detection by PCR and RT-PCR. After detection, the obtained fragments were sequenced to perform phylogenetic analysis of the viruses found. From a total of 108 samples analyzed of different species and locations, ten were positive for circoviruses, six for coronaviruse and 25 for astrovirus, which was the first report of this virus in bats in Brazil. All samples were negative for rabies-related virus. Phylogenetic analyzes revealed that the sequences of circoviruses grouped in both Circovirus and Cyclovirus genus, coronaviruses in Alphacoronavirus genus in two different clades and astroviruses in Mamastrovirus genus along with other bats astrovirus, which form a separate clade from other mammals. Results demonstrate a genetic diversity among viruses found in different species of bats, which have different diets and habitats.

The thesis has optimized DNA isolation from pure yoghurt cultures and yoghurt products. The isolated DNA was than subjected to RT-PCR analysis. In the first part of the thesis, DNA isolation from pure yoghurt cultures using a commercial kit was evaluated as more effective than isolation by phenol extraction and magnetic microparticles. To assess the quality and quantity of DNA obtained the spectrophotometric determination of concentration and purity and qPCR were used. DNA of a total of ten pure yoghurt cultures in a quality suitable for PCR was obtained using the commercial kit. In the second part of the thesis, bacterial DNA was isolated from yoghurt products using the same commercial kit with a previous sample washing by lysation solution. DNA of six yoghurt products was isolated this way. Furthermore, two packages of homemade yoghurt were mad of each product, of which DNA was isolated in the same way. DNA obtained from yoghurts was subjected to RT-PCR using six pairs of primers (V3_F a V3_R, V6_F a V6_R, V1_F a V1_R, GroHRM_F a GroHRM_R, UPF a UPR, P1V1 a P2V1) and using the pure cultures DNA as a positive controls. The results confirmed the presence of cultures declared in each yoghurt and their ability to multiply after inoculation into a new medium (milk).

Master of Science / Department of Food Science / Randall Phebus / Shiga toxin-producing Escherichia coli (STEC) are Gram negative rod-shaped bacteria that are causative agents of foodborne disease. While natural flora in the gastrointestinal tracts of bovines and other ruminants, certain enterohemorrhagic STEC strains cause serious or even fatal disease when ingested. In 2012, the USDA identified six STEC serotypes (O26, O45, O103, O111, O121, O145) as particularly dangerous (in addition to O157:H7; STEC-7) based upon data from the Centers for Disease Control and Prevention and designated them adulterants in raw ground beef, its component materials, and non-intact raw beef products. This research addressed three important components for detection of the recently declared STEC adulterant serotypes. Part one evaluated traditional E. coli O157 selective enrichment media, and additional media types and additive levels, for STEC-7 cultural amplification. Buffered peptone water (BPW), universal pre-enrichment broth (UPB), tryptic soy broth (TSB), TSB with 8 mg/L novobiocin, Escherichia coli broth (EC), and EC with 5, 8, and 20 mg/L novobiocin added were evaluated. EC broth performed equally well compared to non-selective media types, but addition of novobiocin supplement, typically used to suppress overgrowth by background flora, suppressed non-O157 STEC growth. Higher levels of novobiocin inhibited most serotypes. Part two tested the ability of transport media to maintain original STEC-7 concentrations as samples are transported to analytical laboratories. Transport media BPW, maximum recovery diluent (MRD), and Cary-Blair transport medium (CB) were inoculated with individual STEC serotypes and held at 4 or 10 °C for 72 h. Growth/survival curves indicated that CB maintained STEC-7 populations nearest to inoculation levels during storage at either temperature. Part three, part of a field study determining STEC-7 prevalence rates for cattle, hides and dressed carcasses, compared qualitative results generated by two molecular-based detection systems (BioControl Assurance GDS® and Neogen NeoSeek™), analyzing 576 selectively enriched beef carcass sponge samples collected from a commercial processing facility. The GDS and NeoSeek systems indicated 28.7 and 6.1 percent presumptive positive rates for STEC-7, respectively. It was speculated the higher GDS prevalence rate was due to false-positive determinations from the mixed culture enrichments, as viable STEC-7 cells were not recovered by immuno-magnetic bead culture isolation.

Transplantation is based on a satisfactory matching of the patient and donor genes for Human Leukocyte Antigen (HLA), which increases the chance of a successful transplantation. HLA gives individual cell surface markers. The Major Histocompatibility Complex (MHC) region, encoding HLA in humans, is the most polymorphic in the human genome. The genes are located on chromosome six and consists of 200 genes. Those genes encode protein products essential for the acquired immune system. MHC molecule’s role is to represent foreign substance for B- and T-lymphocytes. MHC is an important system as it contributes to the activation of the immune system to combat viruses, bacteria, parasites and cancer cells. HLA-typing is determined through certain antigens in the HLA system. The classical transplantation antigens are HLA-A, -B, -C, -DR, -DQ and -DP. By amplifying the DNA with sequence specific primers in the Polymerase Chain Reaction (PCR), the amplicons can be detected and alleles present in the patient genome can be determined. The purpose of this study was to compare occurrence of non-specific DNA binding using master mix where Ampli Taq DNA polymerase is added and master mix with polymerase included in the PCR. Samples from 16 patients were tested with both master mix- solutions. The analyses were performed with primer plates for HLA-A, HLA-B and HLA-DRP1. The results showed that the master mix with Taq polymerase included should be applied, because it gave clearer specific band, better image quality and gave weaker and approximately 30% fewer non- specific DNA binding compared to the master mix with added Taq polymerase.

BACKGROUND:Cryptococcus gattii has been the cause of an ongoing outbreak starting in 1999 on Vancouver Island, British Columbia and spreading to mainland Canada and the US Pacific Northwest. In the course of the outbreak, C. gattii has been identified outside of its previously documented climate, habitat, and host disease. Genotyping of C. gattii is essential to understand the ecological and geographical expansion of this emerging pathogen.METHODS:We developed and validated a mismatch amplification mutation assay (MAMA) real-time PCR panel for genotyping C. gattii molecular types VGI-VGIV and VGII subtypes a,b,c. Subtype assays were designed based on whole-genome sequence of 20 C. gattii strains. Publically available multilocus sequence typing (MLST) data from a study of 202 strains was used for the molecular type (VGI-VGIV) assay design. All assays were validated across DNA from 112 strains of diverse international origin and sample types, including animal, environmental and human.RESULTS:Validation revealed each assay on the panel is 100% sensitive, specific and concordant with MLST. The assay panel can detect down to 0.5 picograms of template DNA.CONCLUSIONS:The (MAMA) real-time PCR panel for C. gattii accurately typed a collection of 112 diverse strains and demonstrated high sensitivity. This is a time and cost efficient method of genotyping C. gattii best suited for application in large-scale epidemiological studies.

Sepsis is commonly caused by bacteria, fungi or both present in the blood stream during inflammation. In response, inflammatory cascades are released in multiple organ systems which if prolonged causes sepsis and can eventually lead to organ failure and death. The major diagnostic technique of sepsis is blood culturing. However, the technique is time consuming and lacks sensitivity; especially in patients under antimicrobial therapy. Molecular techniques particularly PCR could possibly become implemented in sepsis diagnostics in the future. The aim of the thesis was to compare the effect on PCR sensitivity by different PCR kits, with optimized PCR conditions to find an ideal Real-time PCR applicable for direct detection of rRNA or rDNA in whole blood, using the 16S rDNA gene. The study also surveyed the overall background flora of bacterial species circulating in the blood. During the optimization Haemophillus influenzae and Streptococcus pneumoniae were added to whole blood, rRNA or rDNA was isolated and extracted and subsequently processed by Real-time PCR. Four commercially available PCR kits were compared. Attempts using rRNA did not significantly increase the PCR sensitivity. LightCycler FastStart DNA Master SYBR Green I kit (Roche Diagnostics) used for rDNA, generated low cp-values, the cleanest sequences and the finest separation between amplification curves. Twenty whole blood and pre-cultured patient samples were processed by the optimized PCR. The effect on PCR sensitivity by pre-culturing patient blood samples was studied and no statistical difference was noted. Increased PCR sensitivity is essential for implementation of PCR techniques in sepsis diagnostics.

No description available.

No description available.

No description available.

The age structure of populations is an important and often unresolved factor in ecology and wildlife management. Parameters like onset of reproduction and senescence, reproductive success and survival rate are tightly correlated with age. Unfortunately, age information of wild animals is not easy to obtain, especially for birds, where few anatomical markers of age exist. Longitudinal age data from birds banded as chicks are rare, particularly in long lived species. Age estimation in such species would be extremely useful as their long life span typically indicates slow population growth and potentially the need for protection and conservation. Telomere length change has been suggested as a universal marker for ageing vertebrates and potentially other animals. This method, termed molecular ageing, is based on a shortening of telomeres with each cell division. In birds, the telomere length of erythrocytes has been reported to decline with age, as the founder cells (haematopoietic stem cells) divide to renew circulating red blood cells. I measured telomere length in kakapo, the world largest parrot and four other bird species (Buller’s albatross, kea, New Zealand robin and saddleback) using telomere restriction fragment analysis (TRF) to assess the potential for molecular ageing in these species. After providing an overview of methods to measure telomere length, I describe how one of them (TRF) measures telomere length by quantifying the size distribution of terminal restriction fragments using southern blot of in-gel hybridization (Chapter 2). Although TRF is currently the ‘gold standard’ to measure telomere length, it suffers from various technical problems that can compromise precision and accuracy of telomere length estimation. In addition, there are many variations of the protocol, complicating comparisons between publications. I focused on TRF analysis using a non-radioactive probe, because it does not require special precautions associated with handling and disposing of radioactive material and therefore is more suitable for ecology laboratories that typically do not have a strong molecular biology infrastructure. However, most of my findings can be applied to both, radioactive and nonradioactive TRF variants. I tested how sample storage, choice of restriction enzyme, gel Abstract II electrophoresis and choice of hybridization buffer can influence the results. Finally, I show how image analysis (e.g. background correction, gel calibration, formula to calculate telomere length and the analysis window) can not only change the magnitude of estimated telomere length, but also their correlation to each other. Based on these findings, I present and discuss an extensive list of methodological difficulties associated with TRF and present a protocol to obtain reliable and reproducible results. Using this optimized protocol, I then measured telomere length of 68 kakapo (Chapter 3). Almost half of the current kakapo population consists of birds that were captured as adults, hence only their minimum age is known (i.e. time from when they were found +5 years to reach adulthood). Although molecular ageing might not be able to predict chronological age accurately, as calibrated with minimum age of some birds, it should be able to compare relative age between birds. Recently, the oldest kakapo (Richard Henry) was found to show signs of reproductive senescence. The age (or telomere length) difference to Richard Henry could have been used to approximate the remaining reproductive time span for other birds. Unfortunately, there was no change of telomere length with age in cross sectional and longitudinal samples. Analysis of fitness data available for kakapo yielded correlations between telomere length and fledging success, but they were weak and disappeared when the most influential bird was excluded from analysis. The heavy management and small numbers of kakapo make conclusions about fitness and telomere length difficult and highly speculative. However, telomere length of mothers and their chicks were significantly correlated, a phenomena not previously observed in any bird. To test if the lack of telomere loss with age is specific to kakapo, I measured telomere length of one of its closest relatives: the kea (Chapter 4). Like kakapo, telomere length did not show any correlation with age. I then further assessed the usefulness of molecular ageing in birds using only chicks and very old birds to estimate the maximum TL range in an additional long lived (Buller’s albatross) and two shorter lived species (NZ robin and saddleback). In these Abstract III species, telomere length was on average higher in chicks than in adults. However, age matched individuals showed high variations in telomere length, such that age dependent and independent telomere length could not be distinguished. These data and published results from other bird species, coupled with the limitations of methodology I have identified (Chapter 2), indicate that molecular ageing does not work in most (if not all) birds in its current suggested form. Another way to measure telomere length is telomere Q-PCR, a real-time PCR based method. Measurement of the same kakapo samples with TRF and Q-PCR did not result in comparable results (Chapter 4). Through experimentation I found that differences in amplification efficiency between samples lead to unreliable estimation of telomere length using telomere Q-PCR. These differences were caused by inhibitors present in the samples. The problem of differential amplification efficiency in Q-PCR, while known, is largely ignored by the scientific community. Although some methods have been suggested to correct for differing efficiency, most of these introduce more error than they eliminate. I developed and applied an assay based on internal standard oligonucleotides that was able to corrected EDTA induced quantification errors of up to 70% with high precision and accuracy (Chapter 5). The method, however, failed when tested with other inhibitors commonly found in DNA samples extracted from blood (i.e. SDS, heparin, urea and FeCl3). PCR inhibition was highly selective in the probe-polymerase system I used, inhibiting amplification of genomic DNA, but not amplification of internal oligonucleotide or plasmid standards in the same reaction. Internal standards are a key feature of most diagnostic PCR assays to identify false negatives arising from amplification inhibition. The differential response to inhibition I identified greatly compromises the accuracy of these assays. Consequently, I strongly recommend that researchers using PCR assays with internal standards should verify that the target DNA and internal standard actually respond similarly to common inhibitors.