A caracterização de sequências codificadoras presentes nas vizinhanças do gene META 1 permitiu a identificação de alguns genes expressos preferencialmente em estágios infectivos de L. (L.) amazonensis. Um dos genes presentes é regulado de forma distinta, observando-se maior abundância do RNA em formas amastigotas. Este gene foi denominado LaLRR17 por codificar uma proteína contendo em sua região central 6 repetições ricas em leucina (LRR). As LRR são motivos presentes em diversas famílias de proteínas e são responsáveis pela formação de uma estrutura capaz de estabelecer interações protéicas. A região central da proteína LRR17 apresentou similaridade com a porção carboxi-terminal da proteína NOD 3 humana. A proteína LRR17 foi localizada no citosol de macrófagos infectados com L. (L.) amazonensis. Para caracterizar a função da proteína LRR17 foram obtidas linhagens de L. (L.) amazonensis expressoras do gene LmjLRR17. Essas linhagens mutantes foram mais infectivas em macrófagos in vitro quando comparadas com a linhagem selvagem. Avaliamos também o papel das proteínas NOD 1 e NOD 2 na infecção por L. (L.) amazonensis e L. (L.) major para estabelecer a possível relação da proteína LRR17 na interação com essas vias de defesa celular do macrófago. / The characterization of coding sequences in the vicinity of the META 1 gene allowed the identification of some genes preferentially expressed in L. (L.) amazonensis infective stages. One of the identified transcripts presents a distinct pattern of expression with higher levels of mRNA in amastigotes. This gene was named LaLRR17 since it encodes a 72 kDa protein with 6 leucine-rich repeats (LRR) in its central region. Leucine-rich repeats (LRR) are present in several families of proteins and are responsible for the formation of a structure capable of establishing protein interactions. The central region of the LRR17 protein showed similarity with the carboxyl-terminal portion of the NOD 3 human protein. The LaLRR17 protein is secreted to the cytoplasm of L. (L.) amazonensis-infected macrophages. To characterize the function of the LRR17 protein we obtained strains of L. (L.) amazonensis expressing the LmjLRR17 gene. These mutant strains were more infective to macrophages in vitro when compared with the wild type strain. We also evaluated the role of NOD 1 and NOD 2 proteins in infections with L. (L.) amazonensis and L. (L.) major to investigate a possible role of the LRR17 protein in the interaction with these defense pathways in macrophages.

O estudo foi desenvolvido com o intuito de detectar e caracterizar Cryptosporidium spp. em pacientes de diferentes comunidades brasileiras, atendidos no HC-FMUSP. A amostra utilizada foi de 2.410 amostras fecais, provenientes de exames realizados na Divisão de Laboratório Central do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo (DLC-HCFMUSP), no período de 2000 a 2006. A maioria das amostras (96,82%) era oriunda do Estado de São Paulo (DIR 1 a DIR 24), sendo que 56,18% eram do Município de São Paulo (DIR 1). Foi avaliada, também, sua relação com outros enteroparasitos, com dados clínicos e localização geográfica. Todas as amostras fecais foram submetidas a métodos de concentração para pesquisa de enteroparasitos, com resultado positivo de 4,6% e 27,8% para helmintos e protozoários, respectivamente. Oocistos de Cryptosporidium spp. foram detectados, por microscopia óptica após coloração pelo método de Kinyoun em 233 amostras fecais (9,7%), semi quantificados e medidos. A maioria das amostras apresentava pequena quantidade de oocistos. Nos isolados biológicos obtidos foi feito a extração do DNA genômico utilizando 223 amostras fecais preservadas a 20°C negativos, incubadas com solução de lise (Tris-HCl + EDTA + SDS 10% + beta mercaptoetanol + PVP) e proteinase K seguida de extração com fenol-clorofórmio-álcool isoamílico (25:24:1) em tubo Phase Lock Gel light . A amplificação do DNA alvo foi feita com PCR dupla, tendo como marcador genético o gene 18 SSUrRNA. Os produtos da amplificação (amplicons) da PCR - Dupla foram digeridos pelas enzimas de restrição: TaqI e AseI. A PCR dupla confirmou Cryptosporidium em 37,2% (83/223) das amostras fecais analisadas, com sua caracterização em 62,7% (52/83) após a digestão de seus produtos. Foram observados perfis característicos de C. hominis (88,5%), C. parvum (3,8%), Cryptosporidium não parvum não hominis (34,9%) e infecções mistas com C. hominis (27,2%). Os não caracterizados foram considerados Cryptosporidium spp. Cryptosporidium spp. apresentou associações significativas com todos os grupos de riscos avaliados e diarréia. Foi observada correlação estatisticamente significativa entre tamanho dos oocistos detectados na microscopia e os genótipos Cryptosporidium hominis e Cryptosporidium não hominis não parvum. Conclui-se que diferentes genótipos de Cryptosporidium circulam em uma mesma região geográfica, infectando indivíduos tanto imunocompetentes como imunodeprimidos. A maior freqüência de Cryptosporidium hominis indica a rota fecal oral como a mais importante na transmissão desta infecção. Métodos moleculares de genotipagem são essenciais para estudos epidemiológicos deste organismo. / The study was developed with the purpose to detect and characterize Cryptosporidium spp. in patients of different Brazilian communities attended at the HC-FMSUP. Fecal samples from 2,410 individuals were arise from the Central Laboratory Division of the University of São Paulo Medical School Hospital (DLC-HC-FMUSP) searching for enteroparasites, in the period from 2000 to 2006. Most samples (96.82%) were from São Paulo state (DIR 1 to DIR 4) of which 58.18% were from São Paulo city (DIR 1). Their relationship with other enteroparasites, clinical data and geographical localization was also assessed. In the search for enteroparasites, all fecal samples were submitted to concentration methods with a 4.6% and 27.8% positive result for helminths and protozoans, respectively. Cryptosporidium spp. oocysts were detected, semi-quantified and measured in 233 fecal samples (9.7%), using light microscopy after staining by Kinyoun\'s method. Most samples presented few oocysts. In the biologic isolates genomic DNA extraction was performed using 223 fecal samples stored at -20oC, incubated with lysing solution (Tris-HCl + EDTA + 10% SDS + ? mercaptoethanol + PVP) and proteinase K followed by extraction with phenol-chloroform-isoamylic alcohol in a Phase Lock Gel Light tube. Amplification of target DNA was performed with double PCR, with 18 SSUrRNA gene as genetic marker. The double PCR amplification products (amplicons) were digested by TaqI and AseI restriction enzymes. Double PCR confirmed Cryptosporidium in 37.2% (83/223) of the analyzed fecal samples with characterization in 62.7% (52/83) after digestion of its products. Characteristic profiles of C. hominis (88.5%). C. parvum (3.8%), Cryptosporidium non-parvum non-hominis (34.9%) and mixed infection with C. hominis (27.2%) were observed. Those not characterized were considered to be Cryptosporidium spp. Cryptopsoridium hominis presented significant associations with all evaluated risk groups and diarrhea. A statistically significant correlation between size of the oocysts detected by microscopy and the Cryptosporidium hominis and Cryptosporidium non-hominis non-parvum genotypes was observed. It is concluded that different Cryptosporidium genotypes circulate in the same geographical region, infecting both immunocompetent and immunodepressed individuals. The higher frequency of Cryptosporidium hominis indicates the fecal-oral pathway as the most important in the transmission of this infection. Molecular genotyping methods are essential for epidemiological studies on this parasite.

A prevalência de patógenos intestinais foi estudada entre os índios da etnia Tapirapé, da Amazônia mato-grossense, por meio de técnicas coproparasitológicas, imunológicas e moleculares. Do total de 1526 amostras, 83,35% apresentaram ao menos um parasito intestinal e 65% tinham mais de um parasito (poliparasitismo). Entamoeba coli foi o mais prevalente (827/1526 - 54,19%). Entamoeba histolytica/dispar (581/1526 - 38,07%), Giardia intestinalis (287/1526 - 18,81%), Blastocystis spp. (257/1526 - 16,84%) e Ancylostoma spp. (293/1526 - 19,20%) também foram freqüentes. Cistos de Giardia intestinalis foram seqüenciados utilizando os genes <font face=\"Symbol\">b-Giardina e gdh. Apenas os assemblages A e B foram encontrados, sendo que o assemblage A foi o mais prevalente. Análise molecular de Blastocystis spp. demonstrou que, por meio do gene SSU-rNA, o subtipo 1 foi o mais dominante entre os Tapirapé, seguido pelos subtipos 2 e 3. Com base nisso, G. intestinalis e Blastocystis spp. são potencialmente zoonóticos. Os resultados corroboram com outros estudos realizados na Amazônia brasileira. / The prevalence of intestinal pathogens was studied in indigenous of the Tapirapé ethnic from Amazon region of Mato Grosso State, using the coproparasitological, immunological and molecular. Of the total 1,526 fecal samples 83.35% had at least one intestinal parasite and 65% had more than one parasite (poliparasitism). The most prevalent parasite was Entamoeba coli (827/1526 - 54.19%). Entamoeba histolytica/dispar (581/1526 - 38, 07%), Giardia intestinalis (287/1526 - 18.81%), Blastocystis spp. (257/1526 - 16.84%) and Ancylostoma spp. (293/1526 -19.20%) were found too. Cysts of G. intestinalis were sequence by <font face=\"Symbol\">b-Giardina and GDH gene. Only assemblages A and B were found and assemblage A was the most prevalent. The molecular characterization of Blastocystis spp. by SSU-rRNA demonstrated that subtype 1 was dominant followed by subtypes 2 and 3. So, G. intestinalis and Blastocystis spp. are potentially zoonotic. The results are in agreement with previous studies conducted in the Brazilian Amazon.

Submitted by Jorge Silva (jorgelmsilva@ufrrj.br) on 2017-05-26T20:25:05Z No. of bitstreams: 1 2012 - Aldenice de Nazar? Silva Pereira.pdf: 1725747 bytes, checksum: dc10ecd0699041a155de6f501045a97a (MD5) / Made available in DSpace on 2017-05-26T20:25:05Z (GMT). No. of bitstreams: 1 2012 - Aldenice de Nazar? Silva Pereira.pdf: 1725747 bytes, checksum: dc10ecd0699041a155de6f501045a97a (MD5) Previous issue date: 2012-03-01 / CNPq / Previous studies of the parasitic fauna of the goatfish (Mullus argentinae) from Brazil and Argentina show a significant diversity of species and suggest that this host feature is a good model to test hypotheses for the distribution of parasites and their use as biological indicators of the presence of stocks or different populations of hosts and allowing information relevant to good management of this species. The purpose of this work was to study the composition and structure of parasites communities of the goatfish (M. argentinae), assess whether the temporal variation influences the parasitic fauna and verify its use as a tool for discrimination of possible stocks of this species throughout its geographical distribution, which includes the coast of Brazil and Argentina. During the period of March 2010 to July 2011, were collected 430 specimens of M. argentinae of three locations along the Brazilian coast and an area of the coast of Argentina. In statistics, the quantitative approach was made at the level of parasitic infrapopulations and ecological descriptors were calculated for each parasite species in each area. Species with prevalence >10% in at least one of the localities were analyzed in the ? ? (Chi-square) to test significant differences in prevalence between locations. ANOVA and a Tukey test a posteriori were performed to test for unequal samples. It was analyzed similarity indices of Jaccard and qualitative Bray-Curtis and quantitative and multivariate analysis. Discriminate analysis was used to detect differences between locations and identify species of parasites responsible for these differences. / Estudos pr?vios da fauna parasit?ria da Trilha (Mullus argentinae) em amostras provenientes do Brasil e da Argentina mostram uma significativa diversidade de esp?cies e sugerem que este recurso ictiol?gico ? um bom modelo para testar hip?teses de distribui??o de parasitos e seu uso como indicadores biol?gicos da presen?a de estoques ou de popula??es diferentes de hospedeiros e que permitam obter informa??es relevantes para um adequado manejo desta esp?cie. O prop?sito deste trabalho foi estudar a composi??o e estrutura das comunidades parasit?rias da Trilha (M. argentinae), avaliar se a varia??o temporal da amostragem influencia na fauna parasit?ria e verificar seu uso como ferramenta para a discrimina??o de poss?veis estoques desta esp?cie ao longo da sua distribui??o geogr?fica, que inclui o litoral do Brasil e da Argentina. Durante o per?odo de mar?o de 2010 a julho de 2011, foram coletados um total de 430 esp?cimes de M. argentinae de tr?s localidades do litoral brasileiro (Rio de Janeiro, Santa Catarina e Rio Grande do Sul) e de uma localidade do litoral da Argentina (Mar Del Plata). A abordagem quantitativa foi feita em n?vel de infrapopula??es parasit?rias, sendo calculados os descritores quantitativos, para cada esp?cie de parasito de cada ?rea estudada. Para as esp?cies com preval?ncia >10% foram feitas an?lises de ?? (qui-quadrado) para testar diferen?as significantivas de preval?ncia entre localidades. ANOVA e um teste Tukey a posteriori foram feitos para testar se existe diferen?a entre grupos. Foram utilizados tamb?m os ?ndices de similaridade qualitativa de Jaccard e quantitativa de Bray-Curtis. Na an?lise multivariada, primeiramente desenvolveu-se uma an?lise de agrupamentos, que agrupa os parasitos pela abund?ncia de esp?cies existentes nas localidades. A An?lise discriminante foi usada para detectar diferen?as entre localidades e entre diferentes ?pocas de coleta e identificar esp?cies de parasitos respons?veis por estas diferen?as.

O estudo foi desenvolvido com o intuito de detectar e caracterizar Cryptosporidium spp. em pacientes de diferentes comunidades brasileiras, atendidos no HC-FMUSP. A amostra utilizada foi de 2.410 amostras fecais, provenientes de exames realizados na Divisão de Laboratório Central do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo (DLC-HCFMUSP), no período de 2000 a 2006. A maioria das amostras (96,82%) era oriunda do Estado de São Paulo (DIR 1 a DIR 24), sendo que 56,18% eram do Município de São Paulo (DIR 1). Foi avaliada, também, sua relação com outros enteroparasitos, com dados clínicos e localização geográfica. Todas as amostras fecais foram submetidas a métodos de concentração para pesquisa de enteroparasitos, com resultado positivo de 4,6% e 27,8% para helmintos e protozoários, respectivamente. Oocistos de Cryptosporidium spp. foram detectados, por microscopia óptica após coloração pelo método de Kinyoun em 233 amostras fecais (9,7%), semi quantificados e medidos. A maioria das amostras apresentava pequena quantidade de oocistos. Nos isolados biológicos obtidos foi feito a extração do DNA genômico utilizando 223 amostras fecais preservadas a 20°C negativos, incubadas com solução de lise (Tris-HCl + EDTA + SDS 10% + beta mercaptoetanol + PVP) e proteinase K seguida de extração com fenol-clorofórmio-álcool isoamílico (25:24:1) em tubo Phase Lock Gel light . A amplificação do DNA alvo foi feita com PCR dupla, tendo como marcador genético o gene 18 SSUrRNA. Os produtos da amplificação (amplicons) da PCR - Dupla foram digeridos pelas enzimas de restrição: TaqI e AseI. A PCR dupla confirmou Cryptosporidium em 37,2% (83/223) das amostras fecais analisadas, com sua caracterização em 62,7% (52/83) após a digestão de seus produtos. Foram observados perfis característicos de C. hominis (88,5%), C. parvum (3,8%), Cryptosporidium não parvum não hominis (34,9%) e infecções mistas com C. hominis (27,2%). Os não caracterizados foram considerados Cryptosporidium spp. Cryptosporidium spp. apresentou associações significativas com todos os grupos de riscos avaliados e diarréia. Foi observada correlação estatisticamente significativa entre tamanho dos oocistos detectados na microscopia e os genótipos Cryptosporidium hominis e Cryptosporidium não hominis não parvum. Conclui-se que diferentes genótipos de Cryptosporidium circulam em uma mesma região geográfica, infectando indivíduos tanto imunocompetentes como imunodeprimidos. A maior freqüência de Cryptosporidium hominis indica a rota fecal oral como a mais importante na transmissão desta infecção. Métodos moleculares de genotipagem são essenciais para estudos epidemiológicos deste organismo. / The study was developed with the purpose to detect and characterize Cryptosporidium spp. in patients of different Brazilian communities attended at the HC-FMSUP. Fecal samples from 2,410 individuals were arise from the Central Laboratory Division of the University of São Paulo Medical School Hospital (DLC-HC-FMUSP) searching for enteroparasites, in the period from 2000 to 2006. Most samples (96.82%) were from São Paulo state (DIR 1 to DIR 4) of which 58.18% were from São Paulo city (DIR 1). Their relationship with other enteroparasites, clinical data and geographical localization was also assessed. In the search for enteroparasites, all fecal samples were submitted to concentration methods with a 4.6% and 27.8% positive result for helminths and protozoans, respectively. Cryptosporidium spp. oocysts were detected, semi-quantified and measured in 233 fecal samples (9.7%), using light microscopy after staining by Kinyoun\'s method. Most samples presented few oocysts. In the biologic isolates genomic DNA extraction was performed using 223 fecal samples stored at -20oC, incubated with lysing solution (Tris-HCl + EDTA + 10% SDS + ? mercaptoethanol + PVP) and proteinase K followed by extraction with phenol-chloroform-isoamylic alcohol in a Phase Lock Gel Light tube. Amplification of target DNA was performed with double PCR, with 18 SSUrRNA gene as genetic marker. The double PCR amplification products (amplicons) were digested by TaqI and AseI restriction enzymes. Double PCR confirmed Cryptosporidium in 37.2% (83/223) of the analyzed fecal samples with characterization in 62.7% (52/83) after digestion of its products. Characteristic profiles of C. hominis (88.5%). C. parvum (3.8%), Cryptosporidium non-parvum non-hominis (34.9%) and mixed infection with C. hominis (27.2%) were observed. Those not characterized were considered to be Cryptosporidium spp. Cryptopsoridium hominis presented significant associations with all evaluated risk groups and diarrhea. A statistically significant correlation between size of the oocysts detected by microscopy and the Cryptosporidium hominis and Cryptosporidium non-hominis non-parvum genotypes was observed. It is concluded that different Cryptosporidium genotypes circulate in the same geographical region, infecting both immunocompetent and immunodepressed individuals. The higher frequency of Cryptosporidium hominis indicates the fecal-oral pathway as the most important in the transmission of this infection. Molecular genotyping methods are essential for epidemiological studies on this parasite.

Thesis (Ph. D.)--University of Washington, 2006. / Vita. Includes bibliographical references (leaves 85-102).

Insects encounter many microorganisms in nature and to survive they have developed counter measures against the invading pathogens. In Drosophila melanogaster research on insect immunity has mainly been focused on infections by bacteria and fungi. We have explored the immune response against natural infections of the parasite Octosporea muscaedomesticae and the Drosophila C virus as compared to natural infections of bacteria and fungi. By using Affymetrix Drosophila GeneChips, we were able to obtain 48 genes uniquely induced after parasitic infection. It was also clearly shown that natural infections led to different results than when injecting the pathogens. In order to search for the ultimate role of the lepidopteran protein hemolin, we used RNA interference (RNAi). We could show that injection of double stranded RNA (dsRNA) of Hemolin in pupae of Hyalophora cecropia led to embryonic malformation and lethality and that there was a sex specific difference. We continued the RNAi investigation of hemolin in another lepidopteran species, Antheraea pernyi, and discovered that hemolin was induced by dsRNA per se. A similar induction of hemolin was seen after infection with baculovirus and we therefore performed in vivo experiments on baculovirus infected pupae. We could show that a low dose of dsHemolin prolonged the period before the A. pernyi pupae showed any symptoms of infection, while a high dose led to a more rapid onset of symptoms. By performing in silico analysis of the hemolin sequence from A. pernyi in comparison with other Hemolin sequences, it was possible to select a number of sites that either by being strongly conserved or variable could be important targets for future studies of hemolin function.

Small broomrape, a holoparasitic weed, is a relatively new weed introduction in the Pacific Northwest that has contaminated a limited number of red clover fields in Oregon. Greenhouse and field studies were conducted to evaluate small broomrape response to common crop and weed species in the Pacific Northwest. Host species in the greenhouse or field study included alfalfa, arrowleaf clover, carrot, celery, common vetch, crimson clover, lettuce, prickly lettuce, red clover, spotted catsear, subterranean clover, white clover, and wild carrot. False-host species included barley, birdsfoot trefoil, creeping bentgrass, cucumber, field corn, fine fescue, flax, Italian ryegrass, nasturtium, oat, orchardgrass, perennial ryegrass, snap bean, sugar pea, sunflower, sweet corn, tall fescue, tomato, and wheat. Non-host species included sugar beet and curly dock. The greenhouse polyethylene bag system provided a rapid and inexpensive screening for plant species host status to small broomrape. Germination and attachment to host roots are initiated by chemical exudates, that may change concentration in response to nutrient availability and microorganisms. Red clover was grown in varying concentrations of ammonium sulfate fertilizer with and without Rhizobium inoculation, and with small broomrape seeds. Neither Rhizobium inoculation nor ammonium concentration influenced the number of small broomrape attachments to red clover roots. A survey was conducted of red clover seed growers with small broomrape-contaminated fields in the Pacific Northwest. Red clover seed from six respondents were cleaned at the same cleaning facility, and the same respondents purchased their seed stock from this cleaning facility. Small broomrape was not identified in red clover fields prior to or during the first clover seed harvest of fall planted red clover in small broomrape-contaminated sites. / Graduation date: 2003

<p>Because species respond individually to climate change, understanding community assembly requires examination of multiple species from a diversity of forest niches. I present the post-glacial phylogeographic history of an understory, parasitic herb (<italic>Epifagus virginiana</italic>, beechdrop) that has an obligate and host specific relationship with a common eastern North American hardwood tree (<italic>Fagus grandifolia</italic>, American beech). The migration histories of the host and parasite are compared to elucidate potential limits on the parasite's range and to understand their responses to shared climate change. Two chloroplast DNA regions were sequenced and 9 microsatellite loci genotyped from parasite specimens collected throughout the host's range. These data were compared with available cpDNA sequences from the host (McLachlan et al. 2005) and host fossil pollen records from the last 21,000 years (Williams et al. 2004). Analyses of genetic diversity reveal high population differentiation in the parasite's southern range, a possible result of long term isolation within multiple southern glacial refuges. Estimates of migration rates and divergence times using Bayesian coalescent methods show the parasite initiating its post-glacial range expansion by migrating northward into the northeast from southern areas, then westward into the midwest, a pattern consistent with the development of high density beech forests. This result is strongly confirmed through spatial linear regression models, which show host density plays a significant role in structuring parasite populations, while the initial migration routes of the host are irrelevant to parasite colonization patterns. Host density is then used as a proxy for the parasite's habitat quality in an effort to identify the geographic locations of its migration corridors. Habitat cost models are parameterized through use of the parasite's genetic data, and landscape path analyses based on the habitat map show a major migration corridor south of the Great Lakes connecting the northeast and midwest. Host density was the major determinant controlling the parasite's range expansion, suggesting a lag time between host and parasite colonization of new territory. Parasites and other highly specialized species may generally migrate slower due to their complex landscape requirements, resulting in disassociation of forest assemblages during these times. From these results, the low migration capacities of highly specialized species may be insufficient to outrun extirpation from their current ranges.</p> / Dissertation

Low noise, directional microphones are critical for hearing aid applications. This thesis is focused on further development of a biomimetic micromachined directional microphone based on the ear structure of the Ormia Ochracea, a parasitic fly able to locate sound sources in the audio frequency range with high accuracy. The development efforts have been on implementing a version of the microphone for a behind the ear (BTE) package while improving the overall optical efficiency and noise level, demonstrating pulsed laser operation for reduced power consumption, and electrostatic control of the microphone diaphragm position for stable operation over a long time. The new packaging method for the microphone addressed the need for tighter placement tolerances along with a redesigned diaphragm and integration of a microscale optical lens array to improve the optical efficiency of the device. The completed packages were characterized for sensitivity improvement and optical efficiency. The overall optical efficiency was significantly increased from less than 1% to the photo diode array collecting 50% of the emitted optical power from the Vertical Cavity Surface Emitting Laser (VCSEL). This, coupled with the new diaphragm design, improved the acoustic performance of the microphones. Consequently, the noise levels recorded on the devices were about 31 dBA SPL, more than 15dB better than conventional directional microphones with nearly 10 times larger port spacing. Since the application for this technology is hearing aids, the power consumed by the working device needs to be at an acceptable level. The majority of the power used by the microphone is from continuously operating the VCSEL with 2mW optical output power. To reduce this power requirement, it was suggested to pulse the VCSEL at high enough frequency with low duty cycle so that the acoustic signals can be recovered from its samples. In this study, it was found that the VCSEL can be pulsed with little to no degradation in signal to noise ratio as long as the thermal mechanical noise dominated the noise spectrum. The results also indicated that a pulse train with a duty cycle of around 20% can be used without a major loss of performance in the device, meaning the device can effectively run at 1/5 of its original power under pulsed operation mode. Finally, a control technique to overcome some inherent problems of the microphone was demonstrated. Since the optical sensitivity of the microphone depends on the gap between the diaphragm grating and the integrated mirror, it is important to keep that bias gap constant during long term operation against environmental variations and charging effects. Using a simple electrostatic bias controller scheme, the sensitivity variation of the microphone was improved by a factor of 7.68 with bias control. Overall, this thesis has addressed several important aspects of a micromachined biomimetic microphone and further demonstrated its feasibility for hearing aid applications.