Microbial diversity and biogeochemical cycling in soda lakes

Soda lakes contain high concentrations of sodium carbonates resulting in a stable elevated pH, which provide a unique habitat to a rich diversity of haloalkaliphilic bacteria and archaea. Both cultivation-dependent and -independent methods have aided the identification of key processes and genes in the microbially mediated carbon, nitrogen, and sulfur biogeochemical cycles in soda lakes. In order to survive in this extreme environment, haloalkaliphiles have developed various bioenergetic and structural adaptations to maintain pH homeostasis and intracellular osmotic pressure. The cultivation of a handful of strains has led to the isolation of a number of extremozymes, which allow the cell to perform enzymatic reactions at these extreme conditions. These enzymes potentially contribute to biotechnological applications. In addition, microbial species active in the sulfur cycle can be used for sulfur remediation purposes. Future research should combine both innovative culture methods and state-of-the-art ‘meta-omic’ techniques to gain a comprehensive understanding of the microbes that flourish in these extreme environments and the processes they mediate. Coupling the biogeochemical C, N, and S cycles and identifying where each process takes place on a spatial and temporal scale could unravel the interspecies relationships and thereby reveal more about the ecosystem dynamics of these enigmatic extreme environments

Bio-optical studies during the JGOFS-equatorial Pacific program: a contribution to the knowledge of the equatorial system

Bio-optical studies, pursued in the equatorial Pacific area during the International Joint Global Ocean Flux Study program, contributed to a better knowledge of this oceanic system. Besides the classical estimation of biogeochemical ``core parameters'' via optical measurements (e.g., Chl a concentration, particulate matter concentration, etc.), several original bio-optical studies included the estimation of the contributions from the various particulate pools and, within the algal pool, from the various phytoplanktonic communities, to the inherent optical properties (attenuation, scattering, absorption) and to stimulated Chl a fluorescence. New insights also were gained concerning the variations in these properties associated with the diel cycle, tropical instability waves, and Kelvin waves. Such studies are critical to improving the interpretation of the spatial and temporal variability of optical properties in terms of biogeochemical quantities. In addition, studies of diel variations of light attenuation by particles, of sun-stimulated fluorescence Chl a, and of the photophysiological parameters of phytoplankton to be used in bio-optical models, all contributed to a better assessment of primary production rates in the equatorial Pacific. (C) 2002 Elsevier Science Ltd. All rights reserved

Tratamento com radio e quimioterapia do carcinoma epidermóide do canal anal: experiência do hospital Barão de Lucena Radiochemotherapy for squamous cell carcinoma of the anal canal: Barao de Lucena hospital experience

Objetivos: Apresentar os resultados e analisar as variáveis implicadas no tratamento e prognóstico do carcinoma epidermóide do canal anal tratado através da radio e quimioterapia no Hospital Barão de Lucena-SUS-PE. Metodologia: Análise dos prontuários de pacientes com diagnóstico de câncer do canal anal submetidos a tratamento radioquimioterápico. O período de acompanhamento foi de junho de 1989 a junho de 2005. Foram incluídos os pacientes com diagnóstico histológico de câncer de canal anal, enquadrados nos estadios I, II, IIIa e IIIb, submetidos a dois ciclos de quimioterapia com 5-fluorouracil (5-FU) na dose de 1g/m²/dia em infusão contínua de 96 horas e cisplatino na dose de 100mg/m² administrado em 6 horas no segundo dia de infusão de cada ciclo, administrados na primeira e terceira semanas do esquema de tratamento radioterápico. Resultados: Avaliamos 108 prontuários de pacientes que preencheram os critérios do protocolo. O tempo médio de seguimento foi de 51 meses (1-182 meses). Houve predomínio do gênero feminino (81,5% dos pacientes). A idade variou de 33 a 83 anos (média de 59 anos). O tipo histológico mais freqüente foi o carcinoma de células escamosas (80,6% dos casos). Em 21 pacientes, foi diagnosticado carcinoma basalóide. Quanto ao grau de diferenciação, prevaleceu o tipo moderadamente diferenciado (61% dos pacientes com carcinoma de células escamosas). O índice de resposta inicial completa foi de 89,8%. Onze pacientes persistiram com tumor após o tratamento radio e quimioterápico. O índice de resposta inicial completa foi menor nos estadios IIIa e IIIb em relação aos estadios I e II com significância estatística (p<0,05). 14 pacientes evoluíram com recidiva tumoral, oito com recidiva local (7,4%) e seis (5,5%) com recidiva linfática e à distância. CONCLUSÕES: O tratamento radioquimioterápico exclusivo do carcinoma epidermóide do canal anal, tem índice de resposta completo bastante elevado com morbidade aceitável. O tratamento cirúrgico ainda tem seu valor nos casos de persistência da lesão e/ou de recidiva local, com resultados satisfatórios.<br>Objectives: To present the results and analyze the variables involved in the treatment and prognosis of squamous cell carcinoma of the anal canal treated by radiotherapy and chemotherapy at the Hospital Barao de Lucena-SUS-PE. Methodology: Analysis of medical records of patients diagnosed with anal cancer treated by chemoradiation. The monitoring period was from June 1989 to June 2005. We included patients with histologically confirmed cancer of the anal canal, framed in stages I, II, IIIa and IIIb, underwent two cycles of chemotherapy with 5-fluorouracil (5-FU) at a dose of 1g / m² / day continuous infusion 96 hours and cisplatin at a dose of 100 mg / m² administered at 6 hours the second day of infusion of each cycle, administered on the first and third weeks of radiotherapy treatment regimen. Results: We evaluated records of 108 patients who met the criteria of the protocol. The mean follow-up was 51 months (1-182 months). There were more females (81.5% of patients). The age ranged from 33 to 83 years (mean 59 years). The most common histological type was squamous cell carcinoma (80.6% of cases). In 21 patients, was diagnosed Basaloid carcinoma. Regarding the degree of differentiation, the most prevalent type was moderately differentiated (61% of patients with squamous cell carcinoma). The rate of initial complete response was 89.8%. Eleven patients had persistent tumor after radiotherapy and chemotherapy. The initial response rate was lower in complete stages IIIa and IIIb compared to stages I and II with statistical significance (p <0.05). 14 patients developed recurrence, eight with local recurrence (7.4%) and six (5.5%) with lymphatic recurrence and distance. CONCLUSIONS: The chemoradiation treatment of unique cell carcinoma of the anal canal, have complete response rate very high with acceptable morbidity. Surgical treatment still has its value in cases of persistent injury and / or local recurrence, with satisfactory results