Spelling suggestions: "subject:"biolological techniques"" "subject:"bybiological techniques""
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Photobiomodulation of human dermal fibroblasts in vitro: decisive role of cell culture conditions and treatment protocols on experimental outcomeMignon, Charles, Uzunbajakava, N.E., Raafs, B., Botchkareva, Natalia V., Tobin, Desmond J. 19 April 2017 (has links)
Yes / Photobiomodulation-based (LLLT) therapies show tantalizing promise for treatment of skin diseases. Confidence in this approach is blighted however by lamentable inconsistency in published experimental designs, and so complicates interpretation. Here we interrogate the appropriateness of a range of previously-reported treatment parameters, including light wavelength, irradiance and radiant exposure, as well as cell culture conditions (e.g., serum concentration, cell confluency, medium refreshment, direct/indirect treatment, oxygen concentration, etc.), in primary cultures of normal human dermal fibroblasts exposed to visible and near infra-red (NIR) light. Apart from irradiance, all study parameters impacted significantly on fibroblast metabolic activity. Moreover, when cells were grown at atmospheric O2 levels (i.e. 20%) short wavelength light inhibited cell metabolism, while negligible effects were seen with long visible and NIR wavelength. By contrast, NIR stimulated cells when exposed to dermal tissue oxygen levels (approx. 2%). The impact of culture conditions was further seen when inhibitory effects of short wavelength light were reduced with increasing serum concentration and cell confluency. We conclude that a significant source of problematic interpretations in photobiomodulation reports derives from poor optimization of study design. Further development of this field using in vitro/ex vivo models should embrace significant standardization of study design, ideally within a design-of-experiment setting.
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Efficacy of Using Environmental DNA (eDNA) to Detect Kirtland’s Snakes (Clonophis kirtlandii)Rikki Ratsch (5931176) 17 January 2019 (has links)
<p>Environmental DNA (eDNA) surveys
utilize DNA shed from animals in order to detect their presence. Since it was
developed, this technique has been applied to numerous species across several
taxa. In some cases, it has been shown to be superior to traditional survey
methods at detecting rare or cryptic species. It allows for the detection of
animals in low numbers and does not require direct capture of an animal. This
allows eDNA to be more effective at detecting rare or cryptic species that
require high survey effort to find. This often reduces survey costs as many eDNA
samples can be collected quickly with little equipment required.</p>
<p>The Kirtland’s Snake (<i>Clonophis kirtlandii</i>) is a small Natricine
snake endemic to the Midwest. It is a species of conservation concern since it
is threatened throughout its range. Due to its cryptic and fossorial lifestyle,
it is also a notoriously difficult snake to survey. This has resulted in a poor
understanding of Kirtland’s Snake life history and population status. Applying
eDNA surveys to this species may increase detection probability, offering a
more efficient way to survey for them. </p>
<p>In this study, a
quantitative PCR (qPCR) assay was designed and tested alongside traditional
coverboard surveys. The assay had a limit of detection of 166 copies of
Kirtland’s Snake DNA. In crayfish burrow sediment, eDNA was found to be
detectable up to 10 days and may persist for up to 25 days. However, only one
detection occurred out of 380 field samples. Coverboard surveys revealed
temporal and spatial variation in Kirtland’s Snake abundance. More snakes were
captured in the spring, during the first field season, and at the south
coverboard transects. Kirtland’s Snake abundance was also found to be related
to the presence of grass and herbaceous vegetation as well as close proximity
to shrubs. Comparing survey methods, coverboards resulted in far better snake
detection, suggesting that eDNA does not offer an advantage over traditional
survey methods for this species. </p>
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Design and Selection of RT-LAMP Primer Sets Targeting SARS-CoV-2 in Complex Human SamplesJosiah Levi Davidson (10723713) 29 April 2021 (has links)
<p>Loop-mediated Isothermal Amplification (LAMP) is a promising
technology to address diagnostic and surveillance testing during public health
crises, such as the current COVID-19 pandemic; however, primer design and assay
optimization remain a barrier to enabling rapid deployment of assays based on
LAMP. Herein, we introduce a design and screening process that allows for strategic
determination of optimally performing primer sets and standardized assay
conditions which enable execution of LAMP at point-of-care (POC) settings using
complex human samples such as saliva. A total of 20 primer sets targeting the
N, E, RdRP, and orf1ab genes of the SARS-CoV-2 were designed, screened, and selected
based on performance metrics such as reaction time, sensitivity, and
specificity. Of these 20 primer sets, only two primer sets (orf1ab.2 and orf1ab.4)
proved to be viable for use in the final assay. Colorimetric RT-LAMP of the
selected primer set, orf1ab.2 was shown to produce a distinct color change in
contrived samples containing heat-inactivated SARS-CoV-2 in 5% saliva. The
limit of detection of our assay using primer set orf1ab.2 was determined to be 1000
copies/µL of saliva
collected. Furthermore, methods are introduced which allow for the
high-throughput design of LAMP primers using standard software tools and the <i>in-silico</i>
performance of LAMP primer sets. </p>
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ASSESSING DIFFERENT MONITORING TECHNIQUES FOR JUVENILE GREEN TURTLES (CHELONIA MYDAS) IN THE BAHAMASLaura Christine St Andrews (10711260) 27 April 2021 (has links)
<div>Sea turtles are integral components of many marine ecosystems. Green turtles (Chelonia mydas) are generally herbivorous, feed primarily on seagrasses, and are endangered in the Caribbean. The species utilizes extensive marine habitats for foraging and migratory routes, and because of its broad distribution, it is difficult to conduct population assessments. Here, I assessed commonly used techniques for monitoring green turtles in the wild. Specifically: (1) biopsy sampling for molecular assays and (2) unoccupied aerial vehicles (UAVs) deployment and boat-based surveys for population monitoring.</div><div><br></div><div>Skin biopsies are collected from sea turtles for a variety of molecular analyses; however, very little information exists on the natural healing rates at the site of the biopsy in the wild. In Chapter 2, I monitored the healing rates of 17 juvenile green turtles in Eleuthera, The Bahamas, for up to 488 d after taking a 6mm biopsy tissue sample. Complete tissue repair and maturation was observed after a year and a half, and there was no evidence of infection at any point during the healing process. While scarring persisted for several months, biopsy sampling had minimal long-term impact.</div><div><br></div><div>UAVs are increasingly being used to monitor marine megafauna. In Chapter 3, I evaluated the efficacy of using UAVs to detect sea turtles when compared to boat-based surveys. During UAV surveys, the UAV was flown along preprogrammed routes in four creek systems. A boat survey was conducted simultaneously on the same path. I used regression analyses for each survey type to assess the effects of environmental variables on turtle detection rates My results indicate that there were no statistically significant difference between the numbers of turtle detected via boat or UAV surveys; however, there were clear differences in the time and potential cost associated with either method.</div>
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Toxoplasma gondii: diagnóstico da infecção experimental e natural em pombos (Columba livia) por técnicas sorológicas, biológicas e moleculares. / Toxoplasma gondii: diagnosis of experimental and natural infection in pigeons (Columba livia) by serological, biological and molecular techniques.Godoi, Fernanda Sartori Lima de 15 December 2009 (has links)
O trabalho teve por objetivo diagnosticar a infecção experimental e natural por Toxoplasma gondii em pombos (Columba livia), por técnicas sorológicas, biológicas e moleculares. Pombos foram infectados com oocistos esporulados de T. gondii e acompanhados por 60 dias com coleta de soro semanal para o acompanhamento da curva de anticorpos séricos e eutanásia quinzenal para avaliar a presença do parasito em diferentes tecidos. Observou-se concordância em todas as técnicas utilizadas, indicando serem eficazes no diagnóstico da infecção nessa espécie. Pombos de vida livre foram capturados nos municípios de São Paulo, Sorocaba e Ibiúna e anticorpos anti-T. gondii não foram observados. Nestas aves o bioensaio em camundongos foi realizado, independente da ausência de anticorpos e em nenhuma foi possível o isolamento do parasito. / The study aimed to diagnose the experimental and natural infection by Toxoplasma gondii in pigeons (Columba livia), by serological, biological and molecular techniques. Pigeons were infected with sporulated oocysts of T. gondii and monitored for 60 days with weekly serum collection for monitoring the curve of serum antibodies and euthanasia two weeks to assess the presence of parasites in different tissues. Agreement was observed in all the techniques used, indicating to be effective in the diagnosis of infection in this species. Free-living pigeons were captured in the municipalities of São Paulo, Sorocaba and Ibiúna and anti-T. gondii antibodies were not observed. In birds the bioassay was conducted in mice, regardless of the absence of antibodies and none was possible to isolate the parasite.
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Percepção e presença-o corpo na escultura, cinema e biotecnologiasTaborda, Sérgio January 1999 (has links)
No description available.
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Toxoplasma gondii: diagnóstico da infecção experimental e natural em pombos (Columba livia) por técnicas sorológicas, biológicas e moleculares. / Toxoplasma gondii: diagnosis of experimental and natural infection in pigeons (Columba livia) by serological, biological and molecular techniques.Fernanda Sartori Lima de Godoi 15 December 2009 (has links)
O trabalho teve por objetivo diagnosticar a infecção experimental e natural por Toxoplasma gondii em pombos (Columba livia), por técnicas sorológicas, biológicas e moleculares. Pombos foram infectados com oocistos esporulados de T. gondii e acompanhados por 60 dias com coleta de soro semanal para o acompanhamento da curva de anticorpos séricos e eutanásia quinzenal para avaliar a presença do parasito em diferentes tecidos. Observou-se concordância em todas as técnicas utilizadas, indicando serem eficazes no diagnóstico da infecção nessa espécie. Pombos de vida livre foram capturados nos municípios de São Paulo, Sorocaba e Ibiúna e anticorpos anti-T. gondii não foram observados. Nestas aves o bioensaio em camundongos foi realizado, independente da ausência de anticorpos e em nenhuma foi possível o isolamento do parasito. / The study aimed to diagnose the experimental and natural infection by Toxoplasma gondii in pigeons (Columba livia), by serological, biological and molecular techniques. Pigeons were infected with sporulated oocysts of T. gondii and monitored for 60 days with weekly serum collection for monitoring the curve of serum antibodies and euthanasia two weeks to assess the presence of parasites in different tissues. Agreement was observed in all the techniques used, indicating to be effective in the diagnosis of infection in this species. Free-living pigeons were captured in the municipalities of São Paulo, Sorocaba and Ibiúna and anti-T. gondii antibodies were not observed. In birds the bioassay was conducted in mice, regardless of the absence of antibodies and none was possible to isolate the parasite.
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Role Of Tumor Microenvironment in Breast Cancer MetastasisAparna B. Shinde (5930267) 10 June 2019 (has links)
<p>Metastasis of primary
mammary tumors to vital secondary organs is the primary cause of breast cancer-associated
death, with no effective treatment. Metastasis is a highly selective process
that requires cancer cells to overcome multiple barriers to escape the primary
tumor, survive in circulation, and eventually colonize distant secondary
organs. One of the important aspects of metastatic cancers is the ability to
undergo epithelial-mesenchymal transition (EMT) and the reverse process
mesenchymal-epithelial transition (MET) process. Constant interconversion of
tumor cells between these phenotypes creates epithelial-mesenchymal heterogeneity
(EMH) and interaction between these tumor cell types and the stromal cell
compartment is clearly important to metastasis. In healthy tissues, stromal
cells maintain the composition and structure of the tissue through the production
of extracellular matrix (ECM) proteins and paracrine signaling with epithelial
cells. However, little is known about how EMH
promotes changes in the ECM to promote breast cancer progression and
metastasis. Cancer cells also secret exosomes, nano-size extracellular
vesicles, to establish intercellular communication with distant organs in order
to induce metastasis. These exosomes contain a plethora of different proteins
including extracellular matrix proteins and matrix crosslinking enzymes.
Fibronectin, an important ECM protein, plays an active role in tumor
progression and is often crosslinked by tissue transglutaminase 2 (TGM2) to
promote fibrosis in cancer. Both FN and TGM2 exist in exosomes and are
expressed by heterogenous breast tumors. Although FN and TGM2 have been
reported to play essential roles in cancer, their involvement in metastasis
remains unclear. This work utilizes a variety of approaches to investigate the
role of tumor heterogeneity and ECM proteins in promoting breast cancer
metastasis. In this dissertation, we establish that mesenchymal cells
expressing intracellular FN are held in a stable non-metastatic mesenchymal
phenotype and produce cellular fibrils containing functionalized FN capable of
supporting the growth of metastatic competent epithelial cells. We introduce a
novel 3D culture system consisting of a tessellated scaffold which is capable
of recapitulating cellular and matrix phenotypes <i>in vivo. </i>Further, we
also demonstrate breast tumor cells secrete exosomes containing TGM2
crosslinked FN fibrils to promote premetastatic niche formation and induction
of metastasis.<i> </i>Using genetic approaches, we establish TGM2 is essential
and sufficient to drive metastasis. Finally, we demonstrate pharmacological
inhibition of TGM2 offers a potential therapeutic strategy to treat metastatic
breast cancer. Altogether, our research provides insights into the mechanism
through which TGM2 promotes metastatic breast cancer. This work will help in
developing new drugs to target TGM2 aimed at reducing breast cancer metastasis.<br></p>
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Identification and characterization of microRNAs which moderate neutrophil migration and acute inflammationAlan Y Hsu (8912033) 09 September 2022 (has links)
<p>Neutrophils are the first cells recruited to an immune
stimulus stemming from infection or sterile injuries via a mixture of
chemoattractant cues. In addition to eliminating pathogens, neutrophils
coordinate the overall inflammation by activating and producing inflammatory
signals in the tissue while modulating the activation of other immune cells
which in some cases leads to adverse tissue damage. Over amplified or chronic
neutrophil recruitment directly leads to autoimmune diseases including
rheumatic arthritis, diabetes, neurodegenerative diseases, and cancer.
Dampening neutrophil recruitment is a strategy to intervene in
neutrophil-orchestrated chronic inflammation. Despite intensive research over
the past several decades, clinical studies targeting neutrophil migration have
been largely unsuccessful, possibly due to the prominent redundancy of adhesion
receptors and chemokines. Additional challenges lie in the balance of dampening
detrimental inflammation while preserving immunity. Neutrophils are terminally
differentiated cells that are hard to study in cell culture. Mouse models are
often used to study hematopoiesis, migration, and chemotaxis of neutrophils but
is very labor intensive. To discover novel therapeutic targets that modulate
neutrophil migration, we performed a neutrophil-specific microRNA (miRNA)
overexpression screen in zebrafish and identified eight miRNAs as potent
suppressors of neutrophil migration. We have generated transgenic zebrafish
lines that overexpresses these candidate miRNAs where we recapitulated the
mitigation in neutrophil motility and chemotaxis to tissue injury or infection.
Among those we further characterized two miRNAs which have not been reported to
regulate neutrophil migration, namely miR-722 and miR-199.</p>
<p> </p>
<p>MiR-722 downregulates the transcript level of <i>rac2</i> through binding to the <i>rac2</i> 3'UTR. Furthermore, miR-722-overexpressing
larvae display improved outcomes in both sterile and bacterial systemic models,
which correlates with a robust upregulation of the anti-inflammatory cytokines
in the whole larvae and isolated neutrophils. miR-722 protects zebrafish from lethal lipopolysaccharide
challenge. In addition, overexpression of mir-722 reduced chemotaxis of human
neutrophil like cells, indicating that miR-722
is a potential agent to reduce inflammation in humans. </p>
<p>MiR-199<i>,</i> decreases neutrophil chemotaxis in zebrafish
and human neutrophil-like cells. Intriguingly, in terminally differentiated
neutrophils, miR-199 alters the cell cycle-related pathways and
directly suppresses cyclin-dependent kinase 2 (<i>cdk2</i>), whose known
activity is restricted to cell cycle progression and cell differentiation.
Inhibiting Cdk2, but not DNA replication, disrupts cell polarity and chemotaxis
of zebrafish neutrophils without inducing cell death. Human neutrophil-like
cells deficient in CDK2 fail to polarize and display altered signaling
downstream of the formyl peptide receptor. Chemotaxis of primary human
neutrophils is also reduced upon CDK2 inhibition. Furthermore, miR-199 overexpression
or CDK2 inhibition significantly improves the outcome of lethal systemic
inflammation challenges in zebrafish. </p>
<p> </p>
<p>In summary, our results reveal previously unknown functions
of these miRNAs, and
provide potential avenues to modulate neutrophil migration as well as lead to
discoveries of novel factors which can regulate this process. We have also
discovered a non-classical role of CDK2 in regulating neutrophil migration
which provides directions for alleviating systemic inflammation and a better
understanding of neutrophil biology. </p>
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