Heterologous Hyaluronic Acid Production in Kluyveromyces lactis.

Hyaluronic Acid (HA) is a biopolymer composed by the monomers Glucuronic Acid (GlcUA) and N-Acetyl Glucosamine (GlcNAc). It has a broad range of applications in the field of medicine, being marketed between USD 1000-5000/kg. Its primary sources include extraction of animal tissue and fermentation using pathogenic bacteria. However, in both cases, extensive purification protocols are required to prevent toxin contamination. In this study, aiming at creating a safe HA producing microorganism, the generally regarded as safe (GRAS) yeast Kluyveroymyces lactis is utilized. Initially, the hasB (UDP-Glucose dehydrogenase) gene from Xenopus laevis (xlhasB) is inserted. After that, four strains are constructed harboring different hasA (HA Synthase) genes, three of humans (hshasA1, hshasA2, and hshasA3) and one with the bacteria Pasteurella multocida (pmhasA). Transcript values analysis confirms the presence of hasA genes only in three strains. HA production is verified by scanning electron microscopy in the strain containing the pmHAS isoform. The pmHAS strain is grown in a 1.3 l bioreactor operating in a batch mode, the maximum HA levels are 1.89 g/L with a molecular weight of 2.097 MDa. This is the first study that reports HA production in K. lactis and it has the highest HA titers reported among yeast.

Effect of Pyruvate Decarboxylase Knockout on Product Distribution Using Pichia pastoris (Komagataella phaffii) Engineered for Lactic Acid Production.

Lactic acid is the monomer unit of the bioplastic poly-lactic acid (PLA). One candidate organism for lactic acid production is Pichia pastoris, a yeast widely used for heterologous protein production. Nevertheless, this yeast has a poor fermentative capability that can be modulated by controlling oxygen levels. In a previous study, lactate dehydrogenase (LDH) activity was introduced into P. pastoris, enabling this yeast to produce lactic acid. The present study aimed to increase the flow of pyruvate towards the production of lactic acid in P. pastoris. To this end, a strain designated GLp was constructed by inserting the bovine lactic acid dehydrogenase gene (LDHb) concomitantly with the interruption of the gene encoding pyruvate decarboxylase (PDC). Aerobic fermentation, followed by micro-aerophilic culture two-phase fermentations, showed that the GLp strain achieved a lactic acid yield of 0.65 g/g. The distribution of fermentation products demonstrated that the acetate titer was reduced by 20% in the GLp strain with a concomitant increase in arabitol production: arabitol increased from 0.025 g/g to 0.174 g/g when compared to the GS115 strain. Taken together, the results show a significant potential for P. pastoris in producing lactic acid. Moreover, for the first time, physiological data regarding co-product formation have indicated the redox balance limitations of this yeast.

Sulfamethoxazole and ciprofloxacin removal using a horizontal-flow anaerobic immobilized biomass reactor.

The antibiotics sulfamethoxazole (SMTX) and ciprofloxacin (CIP) are commonly used in human and veterinary medicine, which explains their occurrence in wastewater. Anaerobic reactors are low-cost, simple and suitable technology to wastewater treatment, but there is a lack of studies related to the removal efficiency of antibiotics. To overcome this knowledge gap, the objective of this study was to evaluate the removal kinetics of SMTX and CIP using a horizontal-flow anaerobic immobilized biomass reactor. Two different concentrations were evaluated, for SMTX 20 and 40 µg L(-1); for CIP 2.0 and 5.0 µg L(-1). The affluent and effluent analysis was carried out in liquid chromatography/tandem mass spectrometry (LC-MS/MS) with the sample preparation procedure using an off-line solid-phase extraction. This method was developed, validated and successfully applied for monitoring the affluent and effluent samples. The removal efficiency found for both antibiotics at the two concentrations studied was 97%. Chemical oxygen demand (COD) exhibited kinetic constants that were different from that observed for the antibiotics, indicating the absence of co-metabolism. Also, though the antibiotic concentration was increased, there was no inhibitory effect in the removal of COD and antibiotics.

Diversity and antimicrobial potential of culturable heterotrophic bacteria associated with the endemic marine sponge Arenosclera brasiliensis.

Marine sponges are the oldest Metazoa, very often presenting a complex microbial consortium. Such is the case of the marine sponge Arenosclera brasiliensis, endemic to Rio de Janeiro State, Brazil. In this investigation we characterized the diversity of some of the culturable heterotrophic bacteria living in association with A. brasiliensis and determined their antimicrobial activity. The genera Endozoicomonas (N = 32), Bacillus (N = 26), Shewanella (N = 17), Pseudovibrio (N = 12), and Ruegeria (N = 8) were dominant among the recovered isolates, corresponding to 97% of all isolates. Approximately one third of the isolates living in association with A. brasiliensis produced antibiotics that inhibited the growth of Bacillus subtilis, suggesting that bacteria associated with this sponge play a role in its health.

Prevalence of temporomandibular disorders symptoms in patients with multiple sclerosis.

The aim of the present study was to assess the prevalence of symptoms of temporomandibular disorders (TMD) in patients with the relapsing-remitting form of multiple sclerosis (MS), the relationship between TMD and the severity of MS, and the presence of TMD symptoms in the evaluated groups. Sixty individuals were evaluated: 30 patients diagnosed with relapsing-remitting MS and 30 control individuals matched for gender and age range with no neurologic pathology. In order to investigate the TMD symptoms, the questionnaires of the EACD (European Academy of Craniomandibular Disorders) and the RDC/TMD (Research Diagnostic Criteria for Temporomandibular Disorders), both validated for TMD research, were administered. To assess the extent of disability produced by MS, the Expanded Disability Status Scale (EDSS) was used. The prevalence of TMD symptoms in patients with MS was 56.7% versus 16.7% for the control group, with a statistically significant difference between the groups (p=0.0016). No correlation was found between the severity of MS and the prevalence of TMD symptoms (Fisher's test, p=1.0).

Prevalence of temporomandibular disorders symptoms in patients with multiple sclerosis / Prevalência de sintomas de Disfunção Temporomandibular em pacientes com Esclerose múltipla

The aim of the present study was to assess the prevalence of symptoms of temporomandibular disorders (TMD) in patients with the relapsing-remitting form of multiple sclerosis (MS), the relationship between TMD and the severity of MS, and the presence of TMD symptoms in the evaluated groups. Sixty individuals were evaluated: 30 patients diagnosed with relapsing-remitting MS and 30 control individuals matched for gender and age range with no neurologic pathology. In order to investigate the TMD symptoms, the questionnaires of the EACD (European Academy of Craniomandibular Disorders) and the RDC/TMD (Research Diagnostic Criteria for Temporomandibular Disorders), both validated for TMD research, were administered. To assess the extent of disability produced by MS, the Expanded Disability Status Scale (EDSS) was used. The prevalence of TMD symptoms in patients with MS was 56.7% versus 16.7% for the control group, with a statistically significant difference between the groups (p=0.0016). No correlation was found between the severity of MS and the prevalence of TMD symptoms (Fisher's test, p=1.0).

O objetivo deste estudo foi pesquisar a prevalência de sintomas de disfunção temporomandibular (DTM) em pacientes com esclerose múltipla (EM) na forma remitente-recorrente e sua relação com o grau de acometimento da doença e a presença de sintomas de DTM entre os grupos avaliados. Foram avaliados 60 indivíduos, sendo 30 com diagnóstico de EM e 30 controles pareados em gênero e faixa etária. Para avaliação de sintomas de DTM, foi aplicado o questionário recomendado aos clínicos pela Academia Europeia das Desordens Craniomandibulares . Para avaliação do nível de acometimento da EM foi utilizada a escala EDSS (Expanded Disability Status Scale). Os resultados da pesquisa mostraram que a prevalência de sintomas de DTM em pacientes com EM foi de 56,7% e 16,7% para o controle, havendo diferença estatística significativa entre os grupos. Não houve correlação entre o nível de acometimento pela EM e a prevalência de sintomas de DTM.