Comparison of the intrinsic disorder propensities of the RuBisCO activase enzyme from the motile and non-motile oceanic green microalgae.

Green oceanic microalgae are efficient converters of solar energy into the biomass via the photosynthesis process, with the first step of carbon fixation in the photosynthesis being controlled by the enzyme ribulose-1, 5-bisphosphate carboxylase/oxygenase (RuBisCO), which is a large proteinaceous machine composed of large (L, 52 kDa) and small (S, 12 kDa) subunits arranged as a L8S8 hexadecamer that catalyzes the formation of 2 phosphoglyceric acid molecules from one ribulose 1,5-bisphosphate (RuBP) molecule and one of carbon dioxide (CO2) and that is considered as the most abundant protein on Earth. The catalytic efficiency of this protein is controlled by the RuBisCO activase (RCA) that interacts with RuBisCO and promotes the CO2 entrance to the active site of RuBisCO by removing RuBP. One of the peculiar features of RCA is the presence of functional disordered tails that might play a role in RCA-RuBisCO interaction. Based on their ability to move, microalgae are grouped into 2 major class, motile and non-motile. Motile microalgae have an obvious advantage over their non-motile counterparts because of their ability to actively migrate within the water column to find the most optimal environmental conditions. We hypothesizes that the RCA could be functionally different in the non-motile and motile microalgae. To check this hypothesis, we conducted a comparative computational analysis of the RCAs from the representatives of the non-motile (Ostreococcus tauri) and motile (Tetraselmis sp. GSL018) green oceanic microalgae.

Morfologia de frutos, sementes e plântulas de Averrhoa bilimbi L. oriundas de dois estágios de maturação / Fruits, seeds and seedlings morphology of Averrhoa bilimbi L. derived from two stages of maturation

Este trabalho teve por objetivo descrever as características morfológicas de frutos, sementes e plântulas de Averrhoa bilimbi L. oriundas de frutos imaturos e maduros. Os frutos de A. bilimbi foram separados de acordo com a sua coloração em frutos imaturos e maduros. O registro das características morfológicas dos frutos, sementes e plântulas foram realizados por meio de ilustrações manuais, fotografias e descrições de todos os aspectos morfológicos. Para o estudo da morfologia da germinação e plântula, foram semeadas quatro repetições de 25 sementes sobre substrato papel mata-borrão e levadas ao germinador tipo B.O.D., regulado à temperatura constante de 30°C e regime de luz contínua. Os frutos tanto imaturos como maduros variaram apenas quanto ao tamanho, consistência e coloração, sendo as demais características comuns à espécie. As sementes dos frutos imaturos e maduros diferenciaram-se quanto à turgescência dos tecidos, assim como sua coloração, brilho e textura. A germinação é do tipo epígea e fanerocotiledonar, com início no sétimo dia e término no décimo quinto dia após semeadura, com a obtenção da plântula normal. .

This study aimed to describe the fruits, seeds and seedlings morphological characteristics of Averrhoa bilimbi L. immature and mature fruits. The A. bilimbi fruits were separated according to color in immature and mature fruits. The record of fruits, seeds and seedlings morphological characteristics were performed by means of manual illustrations, photographs and morphological aspects descriptions. To study the germination and seedling morphology were take four replications of 25 seeds sown on blotter paper substrate and brought to B.O.D. adjusted in constant temperature 30°C under continuous light. The immature and mature fruits varied only in size, consistency and color, and other characteristics were common to the species. The seeds of immature and mature fruits could distinguished regarding the tissues turgor, as well as its color, luster and texture. The germination is phanerocotylar and epigeal, commencing on the seventh day and ending on the fifteenth day after seeding by obtaining normal seedling.

Superação da dormência em sementes de crista de galo / Overcoming of dormancy of crista de galo in seeds

O presente trabalho teve como objetivo avaliar o efeito de diferentes tratamentos pré-germinativos na superação da dormência de sementes de Celosia cristata L., que foram submetidas aos seguintes tratamentos: choque térmico - exposição em estufa a 80°C por 5 minutos, escarificação química com ácido sulfúrico por um minuto, 30 segundos e 5 minutos, imersão das sementes intactas em água a 80°C até resfriamento, imersão das sementes intactas em água à temperatura ambiente por 24 horas e a testemunha - sem tratamento. Na avaliação do efeito dos tratamentos, foram determinados a porcentagem final, primeira contagem e índice de velocidade de germinação, como também o comprimento da raiz e do hipocótilo. As sementes de C. cristata L. quando oriundas de frutos maduros não necessitam da utilização de tratamentos para superação da dormência.

This study had the objective of evaluating the effect of different pre-germination treatments for overcome of dormancy of Celosia cristata seeds, subjected to the following treatments: heat shock - exhibition in an oven at 80°C for 5 minutes, chemical scarification with sulfuric acid for 1 minute, 30 seconds and 5 minutes, immersion of intact seeds in water the 80°C at cooling and immersion of intact seeds in water for 24 hours, and the control - no treatment. We evaluated the following final percentage, first count and germination speed index, but also the length of the primary root and hypocotyl. The seeds of C. cristata when coming from ripe fruits do not require the use of treatments to overcoming dormancy.

A strategy to obtain axenic cultures of Arthrospira spp. cyanobacteria.

A strategy to obtain axenic cultures of the cyanobacterium Arthrospira sp. ('platensis') Lefevre 1963/M-132-1 strain, consisting of a series of physical and chemical procedures, and the application of an optimized pool of antibiotics, is described in this paper. This strategy, which is an inexpensive and fast way to obtain axenic cultures, can be applied to Arthrospira spp. from culture collections or samples from their natural habitats to eliminate a wide spectrum of contaminants. A high alkaline treatment (pH 12, using KOH) of 72 h is a determinant initial procedure applied to eliminate protozoa and Microcystis sp. Bacteria were eliminated by an optimal antibiotic pool treatment, and Chroococcus sp. residuals were discarded by serial dilution. Optimal concentrations of the antibiotics composing the pool were obtained by a 2(4) factorial central composite rotatable design (CCRD) and Response Surface Methodology (RSM), resulting in: ampicillin 61.6 µg/ml, penicillin 85.8 µg/ml, cefoxitin 76.9 µg/ml, and meropenem 38.9 µg/ml. The results also indicate that cefoxitin was the most effective antibiotic of this pool. After obtaining the axenic culture, identification of Lefevre 1963/M-132-1 strain was performed using amplification and sequencing of the ITS region (including part of 16S rRNA, tRNA Ile, ITS, tRNA Ala and part of 23S rRNA region) and fatty acid composition data. Data base comparison revealed that Lefevre strain is closely related to A. platensis species (99% identity), while fatty acid composition data suggested A. maxima. These seemingly contradictory results are discussed.

Monitoreo y medidas de mitigación de los niveles de ruido alrededor de centros hospitalarios de Lima Metropolitana / Monitoring and measures to mitigate levels of noise arround the hospital centers in Lima city

El programa de monitoreo de exposición a ruido en siete establecimientos de salud de la capital peruana arroja niveles elevados entre 68 dB a 110 dB en horarios comprendidos de 07:01 a 22:00 horas y entre 62 a 92 dB de 22:01 a 07:00, cuando la norma señala no exceder los 50 dB y 40 dB respectivamente. La repercusión negativa de los efectos fisiológicos y psicológicos generales por la exposición al ruido, lo define como un elemento importante de contaminación ambiental. Para nuestro caso, la principal fuente contaminante está constituída por el parque automotor que se desplaza sobre todo por las calles aledañas a los centros hospitalarios. La mayoría de la población considera al paisaje urbano de los hospitales como zona ruidosa y altamente ruidosa. Se sugieren estudios epidemiológicos y recomienda medidas para mitigar los niveles de ruido encontrados, como forestación, pantallas acústicas, cabinas, equipos, protección personal, entre otros, considerando que el hospital debe brindar a sus pacientes un significativo valor terapéutico a través de comodidad personal, facilidad de acceso y movimiento, así como la provisión de intimidad y descanso.