O triptofano é um aminoácido essencial, sendo o precursor do neurotransmissor serotonina. Esse composto é suscetível a oxidação por ação do oxigênio singleto, o que atrai interesse acadêmico devido a sua associação com doenças como a catarata. Nesse sentido, o presente trabalho se dedicou a investigar as propriedades estruturais e espectroscópicas de quatro moléculas envolvidas nessa oxidação: triptofano, triptofano hidroperóxido, tautômero anelar do triptofano hidroperóxido (WOOH) e álcool (WOH) reduzido dessa última molécula, através da aplicação de técnicas de Química Quântica: Teoria de Pertubação e Teoria do Funcional de Densidade Dependente do Tempo, e de simulação computacional: Método de Monte Carlo e Dinâmica Molecular. Foram analisadas as formas estruturais preferenciais do triptofano (neutra ou zwiteriônica) dependendo do meio (vácuo ou água), investigou-se a formação de ligações de hidrogênio e se obteve teoricamente os espectros UV-vis e de Ressonância Magnética Nuclear para esse aminoácido. Esses dois espectros também foram calculados para as moléculas de WOOH e WOH. Para o triptofano hidroperóxido, que é uma molécula postulada, se avaliou a plausibilidade de sua existência, assim como uma possível razão para sua não observação experimental. / Tryptophan is an essential amino acid, being the precursor of neurotransmitter Serotonin. This compound is susceptible to oxidation by singlet molecular oxygen, which has attracted academic interest due to its association with disorders like cataract. In this sense, this work was dedicated to investigate the structural and spectroscopic properties of four molecules involved in this oxidation: tryptophan, tryptophan hydroperoxide, ring chain tautomer of tryptophan hydroperoxide (WOOH) and an alcohol (WOH) reduced from this latter molecule, by means of Quantum Chemistry techniques: Pertubation Theory and Time- Dependent Density Functional Theory, as well as computer simulation: Monte Carlo method and Molecular Dynamics. The preferential conformations of tryptophan (neutral or zwitterionic) depending upon the medium (vacuum or water) were analyzed, in addition it was investigated the formation of hydrogen bonds and obtained the theoretical UV-vis and Nuclear Magnetic Ressonance spectra of this amino acid. These spectra were also calculated for the WOOH and WOH molecules. Regarding tryptophan hydroperoxide, a postulated molecule, it was evaluated the plausibility of its existence, as well as the reason for its non-experimental observation.

Submitted by Renata Lopes (renatasil82@gmail.com) on 2017-06-14T12:41:46Z No. of bitstreams: 1 renataromanholipinhati.pdf: 1636769 bytes, checksum: 2040ff1c86aef423fdd77a3ebd21b33d (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-06-29T12:10:19Z (GMT) No. of bitstreams: 1 renataromanholipinhati.pdf: 1636769 bytes, checksum: 2040ff1c86aef423fdd77a3ebd21b33d (MD5) / Made available in DSpace on 2017-06-29T12:10:19Z (GMT). No. of bitstreams: 1 renataromanholipinhati.pdf: 1636769 bytes, checksum: 2040ff1c86aef423fdd77a3ebd21b33d (MD5) Previous issue date: 2011-08-16 / FAPEMIG - Fundação de Amparo à Pesquisa do Estado de Minas Gerais / O triptofano é um aminoácido essencial e precursor da síntese de serotonina (5-HT). Variações nos níveis plasmáticos de 5-HT estão relacionadas com alterações de humor, ansiedade, depressão, sono, fadiga e supressão de apetite. Neste estudo foi desenvolvido um método simples, rápido e sensível para a quantificação de triptofano em plasma e que emprega a cromatografia líquida de alta eficiência (CLAE) com detector diode array (DAD) no comprimento de onda fixo de 267 nm. A separação foi realizada em coluna analítica ACE 5 C18 (150 mm x 4,6 mm de diâmetro interno e tamanho da partícula de 5 µm), o tempo de corrida foi de 10 min. A fase móvel foi constituída por solução de acetato de sódio 5 mM e acetonitrila (92:8, v/v) e modo de eluição isocrática (1 mL min-1). A preparação da amostra consistiu na desproteinização do plasma utilizando ácido perclórico 8%. O triptofano foi caracterizado no tempo de retenção de 5 min. A especificidade foi monitorada utilizando matrizes normais, lipêmicas e hemolizadas, não sendo observado nenhum pico interferente no tempo de retenção do triptofano. A linearidade do método foi detectada entre 0,5 a 30,0 µg mL-1 e os coeficientes de variação do teste de precisão foram calculados intra e inter-dia para três concentrações (2,5; 5,0 e 15,0 µg mL-1) apresentando variações de 0,26 a 1,30% (intra-dia) e 3,07 a 3,97% (inter-dia) respectivamente. Exatidão e recuperação satisfatórias foram obtidas por este método, além de utilizar pequenas quantidades de solvente orgânico, caracterizando a técnica como eficiente e ecologicamente amigável. / Trytophan is an essential amino acid and a serotonin (5-HT) synthesis precursor. Altered plasma levels of 5-HT are related to humor and behavioral alterations, anxiety, depression, sleep, fatigue and appetite suppression. In this study, a simple, fast, sensitive and specific high-performance liquid chromatography (HPLC) method was developed for determination of tryptophan with diode array detection (DAD) setting at programmed wavelength (λ = 267 nm). The separation was carried out on an analytical column ACE 5 C18 (150 mm x 4.6 mm internal diameter, 5 μm particle size) in less than 10 min. Mobile phase consisted of 5 mM sodium acetate and acetonitrile (92:8, v/v), isocratically eluted (1 mL min-1). Sample preparation consisted of plasma deproteinization with 8% perchloric acid solution. Tryptophan was characterized by a retention time of 5 min. Specificity was monitored using lipemic and hemolysate plasma samples and any peak was observed at the same retention time of tryptophan. A linear range was detected from 0.5 to 30.0 µg mL-1 and coefficients of variation calculated from intra and inter-day from 3 concentration (2.5; 5.0 e 15.0 µg mL-1) assays precision were 0.26 – 1.30% and 3.07 – 3.97% respectively. Satisfactory accuracy and recovery were obtained by this method, and use small amounts of organic solvent, characterizing the technique as an efficient and eco-friendly.

A indoleamina 2,3-dioxigenase (IDO) desempenha um papel importante na tolerância materno-fetal devido á sua ação de catabolizar o triptofano e, consequentemente, impedir a proliferação de linfócitos T, que necessitam desse aminoácido para se manter. Hormônios da reprodução também participam do processo de sobrevivência do feto alogênico, como a progesterona que bloqueia o estímulo mitogênico da proliferação de células T, modula a produção de anticorpos, favorece a produção de IL-10, etc. e o estradiol, que pode modular o perfil imune Th1 ou Th2 na gestação, dependendo de sua concentração. Contudo, a existência ou não de correlação da ação da IDO com esses hormônios ou vice-versa ainda encontra-se pouco evidenciada. Desta forma este trabalho verificou a influência da expressão da IDO e às ações de hormônios da reprodução e citocinas no ciclo celular de células oriundas de fetos e placenta de gestação a termo de fêmeas de ratas e camundongos em cultivo. Este estudo foi realizado em complementação a um trabalho anterior, no qual foi realizada uma avaliação da expressão da IDO por citometria de fluxo em células uterinas, de placentas e de embriões de ratas e camundongos fêmeas prenhes e não prenhes que foram mantidas em cultivo e suplementadas com estradiol, progesterona, interferon γ, triptofano e 1-metil-DL- triptofano. A avaliação das fases do ciclo celular foi realizada pela citometria de fluxo. De acordo com os resultados, em relação ao efeito dos tratamentos no comportamento das células no ciclo celular, podemos observar que, em ratas prenhes e não prenhes, ao adicionar estradiol, houve maior predominância das células em fase G1 nos períodos de 4 e 24 horas, bem como no grupo de camundongos fêmeas prenhes. Algumas células uterinas de ratas não prenhes tratadas com estradiol, assim como as tratadas com progesterona e interferon γ progrediram no ciclo para fase de síntese nos tempos de 24 e 48 horas. Com a adição de triptofano podemos notar nos grupos de ratas não prenhes, camundongos fêmeas prenhes e não prenhes, um aumento da quantidade de células na fase G1 nos três períodos analisados. No grupo de ratas prenhes foi observado uma predominância celular em fase G1 nos tempos de 4 e 24 horas, sendo que em 48 horas, as células sofreram fragmentação de DNA. As células que foram suplementadas com 1- metil DL - triptofano + triptofano mantiveram o mesmo comportamento no ciclo celular , se mantendo em fase G1 nos tempos de 4, 24 e 48 horas grupos prenhes e não prenhes de ratas e nos tempos de 4 e 24 horas nos grupos de camundongos fêmeas prenhes e não prenhes, estando com seu DNA fragmentado e em fase de síntese, respectivamente, no tempo de 48 horas. A suplementação dos diversos fatores aos cultivos celulares permitiu observar alterações na dinâmica do ciclo celular, representada principalmente por um aumento de células em fase G1 nos grupos de células placentárias e embrionárias que receberam progesterona, estradiol, interferon γ e triptofano e apresentaram um significativo aumento da expressão de IDO, e que permite inferir que provavelmente a síntese de RNAm esteja correlacionada à produção da IDO. / The indoleamine 2,3-dioxygenase (IDO) plays an important role in maternal-fetal tolerance due to its capacity to catabolize tryptophan and thereby preventing the proliferation of T lymphocytes, necessary for their maintenance. Reproductive hormones are also involved in the process of survival of semi-allogeneic fetus, as progesterone that blocks mitogenic stimulation of T cell proliferation, modulates antibodies production, promotes production of IL-10, etc. and estradiol, that can modulate the Th1 or Th2 immune profile during pregnancy, depending on its concentration. However, there is very few evidences regarding a possible correlation between IDO expression and these hormones; thus this study examined the influence of the expression of IDO and the actions of reproductive hormones and cytokines in the cell cycle of cells derived from fetuses and placenta at term gestation of female rats and mice in culture. This study was conducted as a complement to an earlier work, in which an evaluation was made of the IDO expression by flow cytometry in uterine cells, placentas and embryos of pregnant rats and mice and non-pregnant females that were maintained in culture and supplemented with estradiol, progesterone, interferon γ, tryptophan and 1-methyl-DLtryptophan. The cell cycle evaluation was conducted by flow cytometry. According to the results, regarding the effect of treatments on the behavior of the cells in the cell cycle, it was observed that in pregnant and non-pregnant rats after the addition of estradiol, there is a greater predominance of cells in G1 phase at periods of 4 and 24 hours, that also was noted in the group of pregnant female mice. Uterine cells from non-pregnant female rats treated with estradiol and progesterone as well as treated with interferon γ progressed to the phase of synthesis on the cycle, at 24 and 48 hours. With the addition of tryptophanin the groups of non-pregnant rats, pregnant and non-pregnant mice , an increased amount of cells in the G1 phase were observed in the three periods analyzed. In the group of pregnant rats a predominance of cells in the G1 phase was observed in periods of 4 and 24 hours, and 48 hours, where the cells undergone DNA fragmentation. In pregnant and non-pregnant rats the cells supplemented with 1 - methyl - DL - tryptophan + tryptophan remained at G1 phase in periods of 4, 24 and 48 hours and 4 and 24 hours for cells from pregnant and non-pregnant mice , that show ragmented DNA followed by synthesis at 48 hours period. Supplementation of the various factors to cell cultures allowed to observe dynamic changes in the cell cycle, represented primarily by an increase of cells in G1 phase in groups of embryonic and placental cells that received progesterone, estradiol, interferon γ and tryptophan and showed a significant increase in the expression of IDO, that allows us to infer that the mRNA synthesis is probably correlated to the production of IDO.

Apesar de ser bem conhecido que a radiação ultravioleta (UV) causa danos na pele, já foram descritos alguns efeitos benéficos desta radiação, como por exemplo a sensação de bem estar proporcionado pela exposição a luz. Na pele, o triptofano (Trp) é metabolizado a compostos biologicamente ativos, e acredita-se que a síntese de serotonina (SER), um dos metabólitos do Trp, na fototerapia seja parte dos mecanismos de remissão da depressão de pacientes com desordem de humor sazonal. Ainda, a radiação UV induz diretamente a expressão e atividade de TDO, enzima que catalisa a transformação de Trp em quinurenina (KYN), em bactérias, efeito que ainda não havia sido estudado em células humanas. Com isso, o objetivo deste trabalho foi avaliar a habilidade da radiação UV-A em modular a expressão de enzimas envolvidas nas rotas catabólicas do Trp em melanócitos e melanomas. Para isso foi realizada a padronização das condições de radiação UV-A através de ensaio de viabilidade celular, e então definimos condições que não levaram a morte das células (1,5 J/cm2 para melanócitos e 3 e 6 J/cm2 para melanomas). A radiação UV-A aumentou a expressão de IDO e TDO nos melanomas, enzimas que favorecem a progressão tumoral, e não só essas enzimas, houve aumento da expressão de KYNU e KMO, que também estão envolvidas na progressão tumoral. Além disso, a expressão de AANAT e HIOMT, responsáveis pela produção de melatonina (MLT), foi maior nos melanomas após 48 horas da radiação, enquanto a enzima INMT teve sua expressão aumentada em todos os tempos. O aumento de INMT em melanomas é muito interessante e podemos relacionar ao bem estar proporcionado pela exposição à luz, já que o produto dessa enzima, DMT, é conhecido por proporcionar essa sensação, porém o aumento observado na expressão de IDO e TDO em melanomas, indica um efeito nocivo da luz associado a produção de moléculas que estão fortemente ligadas aos processos de progressão e imunoescape tumoral. Os melanócitos parecem possuir menor susceptibilidade a radiação UV-A, pois as únicas enzimas que tiveram expressão aumentada após a radiação foram a KMO e a TPH1, e apesar da enzima TPH1 ter a expressão aumentada, esse aumento foi modesto o que nos levou a pensar que outras células da pele possam ter um papel mais relevante na produção de SER ou então outras condições de radiação. / Although it is well known that ultraviolet (UV) radiation causes skin damage, it was already described some benefits to this radiation, for instance the well-being feelings provided by light exposure. In the skin, tryptophan (Trp) is metabolized to biologically active compounds, and it is believed that the synthesis of serotonin, one of tryptophan metabolites, in phototherapy is part of mechanisms of remission of depression in patients with seasonal mood disorder. Moreover, in bacteria the UV radiation directly induces the expression and activity of TDO, the enzyme that catalyzes the metabolization of Trp to kynurenine (KYN). This effect has not been studied in human cells yet. Therefore, the objective of this work was to evaluate if UV-A radiation modulates the expression of enzymes involved in melanocytes and melanoma Trp metabolism. For this aim, we standardized the UV-A radiation conditions through cell viability assay, and then we defined the better conditions to avoid cell death (1,5 J/cm2 to melanocytes and 3 and 6 J/cm2 to melanomas). The UV-A radiation increased the expression of IDO and TDO in melanomas, enzymes that contribute to tumor immune- escape. The expression of KYNU and KMO also increased, and these enzymes are also involved with some types of tumors progression. Furthermore, the expression of AANAT and HIOMT, responsible for melatonin (MLT) production, was higher in melanomas after 48 hours of radiation while INMT had an increased expression at all times. The increase of INMT by melanomas is very interesting and can be related to the well being provided by exposure to light, since the product of this enzyme, DMT, is known to provide this sensation. However, the observed increased of expression of IDO and TDO in melanomas indicates a harmful effect of light associated with the production of molecules linked to tumor progression and immune-escape processes. The melanocytes appear to be less susceptible to UV-A radiation, because only the enzymes KMO and TPH1 had their expression increased after radiation, and for TPH1 this effect was relatively small. Thus, we believe that other skin cells may have a more relevant role in SER production or other radiation conditions.

The essential amino acid tryptophan is an important substrate for the synthesis of serotonin, melatonin, tryptamine, proteins and the kynurenines. The aim of this study was to investigate tryptophan metabolism along the kynurenine pathway in a low income sub- Saharan HIV/AIDS patient population from the Gauteng Province of South Africa. The first objective was to develop and validate a novel gas chromatography mass spectrometry method to enable reliable quantification of tryptophan and metabolites of the kynurenine pathway in plasma. Validation parameters for the detection of tryptophan, kynurenine, quinolinic acid and nicotinamide conformed to international criteria for newly developed methods. The next objective of the study was to find an appropriate biomarker against which to express the results. Several substances previously described as indicators were assessed and compared, including plasma neopterin, procalcitonin, C-reactive protein, the cytokines IL-2, IL-4, IL-6, IL-10, TNF, and IFN-gamma, as well as factors routinely measured and elsewhere described as biomarkers in HIV, i.e., albumin, the albumin/globulin ratio, haemoglobin and red cell distribution width. Neopterin was shown to be superior as indicator of pro-inflammatory status, as indicator of the degree of immune deficiency, to predict disease progression, to distinguish between patients with and without tuberculosis co-infection and to reflect the success of highly active antiretroviral treatment (HAART). In the analyses of the kynurenine pathway metabolites, tryptophan levels were seen to be significantly lower (24.36 ± 4.14 vs. 43.57 ± 11.85 μmol/l; p<0.0001), while the activity of the enzyme, indoleamine 2,3 dioxygenase (IDO), (K/T:136.03 vs. 52.18; p<0.001), as well as kynurenine (3.21 ± 1.33 vs. 2.14 ± 0.45 μmol/l; p<0.001) and quinolinic acid (4.46 ± 2.32 vs. 0.25 ± 0.058 μmol/l; p<0.001) levels were significantly higher in the total patient group (n=105) than in the control group (n=60). Patients on HAART showed not only significantly higher CD4 counts (296.21 ± 195.50 vs. 170.05 ± 167.26 cells/μl; p=0.003), but also lower inflammatory activity (neopterin: 35.51 ± 35.70 vs. 66.63 ± 40.73 nmol/l; p<0.001 and IL-6: 9.56 ± 12.54 vs. 15.04 ± 19.34 pg/ml; p<0.05), lower IFN-γ (41.43 ± 14.14 vs. 53.68±34.39 pg/ml; p<0.05), higher tryptophan levels (25.13 ± 3.80 vs. 22.04 ± 4.32 μmol/l; p=0.033), lower kynurenine levels (3.08 ± 1.28 vs. 3.58 ± 1.42 μmol/l; p=0.144) and lower quinolinic acid levels (4.03 ± 2.04 vs. 5.77 ± 2.65μmol/l; p=0.072) than patients not on HAART. Tryptophan depletion and IDO activity, as well as the levels of kynurenine and quinolinic acid, were generally greater than in populations from developed countries. Indications are that this can be ascribed to higher levels of inflammatory activity at comparable levels of immune deficiency in the disadvantaged population of this study. The degree of tryptophan depletion and quinolinic acid accumulation found could negatively impact on the physical and neuropsychiatric wellness of the population. Correlations between quinolinic acid, and nicotinamide levels showed a significant contribution of kynurenine pathway metabolism to the plasma levels of nicotinamide. This de novo synthesis of nicotinamide could offer protection against niacin deficiency and NAD depletion in populations with inadequate dietary intake. This is the first study to assess plasma tryptophan, kynurenine, quinolinic acid and nicotinamide levels, as well as IDO activity, pro-inflammatory status and IFN-γ levels, simultaneously in one population and to compare it to that of HIV/AIDS patients in developed countries. / Thesis (PhD)--University of Pretoria, 2015. / tm2015 / Physiology / PhD / Unrestricted

Thesis advisor: Shih-Yuan Liu / Described herein are two projects on the application and effects of BN/CC isosterism on indole-containing compounds. In the first chapter, the synthetic route to an unnatural boron and nitrogen-containing analogue of tryptophan (BN-tryptophan) via late-stage functionalization of BN-indole is disclosed and its spectroscopic properties are reported with respect to the natural amino acid, tryptophan. The incorporation of BN-tryptophan into proteins expressed in E. coli using selective pressure incorporation, a residue specific method of unnatural amino acid incorporation, is then reported and its reactivity and fluorescence in the proteins characterized. In the second chapter, the synthesis of a BN-indole-containing aromatic scaffold is reported and the cation-π binding ability characterized by nuclear magnetic resonance (NMR) monitored titrations is disclosed. The resulting chemical shifts were analyzed using a non-linear curve fitting procedure and the extracted association constants (Ka’s) compared with the natural indole scaffold. Computations were also performed to support the titration results. / Thesis (PhD) — Boston College, 2020. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Chemistry.

京都大学 / 新制・課程博士 / 博士(人間・環境学) / 甲第23272号 / 人博第987号 / 新制||人||233(附属図書館) / 2020||人博||987(吉田南総合図書館) / 京都大学大学院人間・環境学研究科共生人間学専攻 / (主査)教授 林 達也, 教授 船曳 康子, 教授 久代 恵介, 教授 森谷 敏夫 / 学位規則第4条第1項該当 / Doctor of Human and Environmental Studies / Kyoto University / DGAM

This thesis deals with the development and optimization of a method for the determination of tryptophan and its metabolites - serotonin and melatonin - in plant material, in grapevine, during one analysis. It uses a high-pressure liquid chromatography. The theoretical part is about tryptophan, its metabolism and basic properties of its metabolites - serotonin and melatonin. Their occurrence in wine is also discussed. Analytical techniques by which these analytes can be determined are also provided. Then information about modern stationary phases, that are suitable for this species, is included. The experimental part consists of optimization of the method, measurement of calibration dependences and measurement of real samples. It is measured by the method of reverse phase chromatography. As first stationary phase it is used a C18 column with core-shell packing, second is a BEH Phenyl column. The mixture of 10 mM acetate buffer (pH = 4.5) and methanol is used as the mobile phase. For detection UV at wavelength 254 nm is used, then for greater sensitivity mass detectionis is used. The basic conditions for the experiment have been set. At the beginning of the analysis, the mobile phase contains 95 % (v/v) buffer and 5 % (v/v) methanol. Then the methanol content is linearly increased to 80 % (v/v) from...

Major depressive disorder (MDD) is rapidly growing and one of the most common causes of disability and mortality worldwide. People with MDD often display brain changes such as adisrupted balance in neurotransmitters, impaired neurogenesis and neuroplasticity. Traditionally has MDD been treated with medications and talking therapies (psychotherapy). Studies have shown that just around 50 % of people with MDD get improvements from common traditional treatments.Therefore is there a great need for a better understanding of MDD and new treatments. There is now an emerging field of research that indicates that the gut microbiota plays a crucial role in disturbing normal brain functioning in MDD. This connection between the gut and the brain is called the gutbrain axis.The thesis aims to investigate if there is a connection between gut microbiota disruption and MDD and if gut microbiota restoration can be a potential effective future treatment for MDD. Key findings of the thesis were, studies show that people with MDD often display gut microbiota disruption and chronic low grade inflammation. Studies also indicate that this inflammation can cause the specific brain change often displayed in people with MDD. One of the most critical findings in the thesis was that gut brain treatments affect tryptophan metabolism, which affects the risk of MDD. The research area of the gut brain axis is still new and many more studies are needed,particularly in humans.

Recent studies suggest aromatic amino acid catabolism by starter lactococci and flavor adjunct bacteria have a significant impact on off-flavor development during Cheddar cheese ripening. We hypothesized that a flavor adjunct bacterium, Brevibacterium linens BL2, produces off-flavor compounds from aromatic amino acid metabolism that will have a detrimental impact on cheese flavor. The mechanism of tryptophan (Trp) catabolism in Brevibacterium linens BL2, was investigated in a chemically defined medium during incubation in laboratory conditions (no carbohydrate, pH 6.50, 220 rpm, 25°C) and cheese-like conditions (no carbohydrate, 4% NaCl, static incubation, l5°C). In laboratory conditions, metabolic studies and enzyme assays confirmed that Trp was converted to kynurenine and anthranilic acid. However, cells incubated in cheese-like conditions did not utilize Trp, indicating that these enzymes are not likely to be involved in formation of Trp compounds associated with off-flavors in Cheddar cheese. In an attempt to verify the metabolic activity of the cells during incubation by monitoring the amino acid metabolism in chemically defined medium inoculated with B. linens BL2, a capillary electrophoresis-laser-induced fluorescence method was developed that could separate, detect, and quantitate 18 amino acids within 38 min. The data indicated that B. linens BL2 was metabolically active. Presumably, the cells will be metabolically active and metabolize amino acids in cheese as well. The ability to determine the Trp metabolic activity of B. linens BL2 in cheese, and to quantify Trp catabolic compounds in cheese during ripening, requires a quantitative extraction procedure. An analytical method was developed to extract and quantify aromatic amino acids and Trp catabolites from cheese using capillary electrophoresis. Methanol was used to extract Cheddar cheese made with Lactococcus lactis S3 alone and in combination with B. linens BL2 to quantitatively determine the influence of BL2 on the occurrence of aromatic catabolites. All cheeses contained aromatic amino acids, indole acetic acid, and indole. The concentration and time taken for development of these compounds were significantly decreased or delayed by the addition of B. linens BL2. After 6 months of aging, the concentrations of Trp catabolites were significantly lower in cheese made with B. linens BL2. Addition of BL2 did not directly contribute to off-flavors derived from Trp catabolism in Cheddar cheese. Therefore, the hypothesis was rejected.