Review of the development of the transport system in the Caribbean with reference to the establishment of regional institutions and the involvement of aid donors

Includes bibliography

Respiratory metabolism in the marine macroalga, Ulva spp: exploratory studies with the respiratory electron transport system (ETS)

Máster en Oceanografía

Exploring respiration and respiratory electron transport system (ETS) in Ulva spp.

[ES] Respiration is a key ecological index. For either individuals or communities, it can be use to assess carbon and energy, demand and expenditure as well as carbon flow rates through food webs. When combined with productivity measurements it can establish the level of metabolic balance. When combined with measurements of respiratory capacity, it can indicate physiological state. Here, we report pilot studies the metabolism of the green algae, Ulva rotundata that inhabits intertidal pools of Gran Canaria. As a starting point we used the electron transport system (ETS) to differentiate between different growing conditions in the natural environment. We suspected different levels of stress associated with these conditions and looked for the influence of this stress in the ETS measurements. This technique has been successfully applied to study bacteria, phytoplankton and zooplankton in the ocean, but it has not been used to study sessile marine macroalgae. These neritic and littoral macrophytes have major ecological and industrial importance, yet little is known about their respiratory physiology. Such knowledge would strengthen our understanding of the resources of the coastal ocean and facilitate its development and best use. Here, we modified the ETS methodology for Ulva rotundata. With this modified ETS assay we investigated the capacity of Ulva to resist anoxia. We measured respiration with optodes (Fibox 4, Presens) in the dark to the point of oxygen exhaustion and through 24 h of anoxia. Then we exposed the Ulva to light and followed the oxygen increase due to photosynthesis. We discuss here the capacity of Ulva to survive during anoxia.

Development of a fluorescent method for the detection in marine organisms of the respiratory electron transport system

Trabajo realizado por: Maldonado, F.; Packard, T.; Gómez, M.; Santana Rodríguez, J. J

Placental Uric Acid Transport System: Glucose Transporter 9 (SLC2A9)

Placental Uric Acid Transport System: Glucose Transporter 9 (SLC2A9). INTRODUCTION: Pre-eclampsia, a pregnancy-specific disease, contributes substantially to perinatal morbidity and mortality of both the mother and her child. Pre-eclampsia is often associated with high maternal urate serum levels, which in turn has been shown to play a role in the pathogenesis of this disease. The aim of this study was to investigate the glucose transporter GLUT9-mediated placental uric acid transport system. METHODS: In this study western blot, immunofluorescence techniques as well as a transepithelial transport (Transwell) model were used to assess GLUT9 protein expression and, respectively, uric acid transport activity. Electrophysiological techniques and transmission electron microscopy (TEM) were used to characterize the properties and the structure of GLUT9. RESULTS: Uric acid is transported across a BeWo choriocarcinoma cell monolayer with 530 pmol/min. We could successfully overexpress and for the first time purify the GLUT9b isoform using the Xenopus laevis oocytes expression system. Chloride seems to modulate the urate transport system. TEM revealed that GLUT9b isoform is present as monomer and dimmer in the Xenopus laevis overexpression model. A class average of all the particles allowed us to develop a first model of human GLUT9b structure, which was derived from the published crystal structure of the bacterial homologue of GLUT1-4. CONCLUSIONS: In vitro the “materno-fetal” transport of uric acid is slow indicating that in vivo the fetus might be protected from short-term fluctuations of maternal urate serum levels. The low-resolution structure obtained from TEM validates the proposed homology model regarding the structure of human GLUT9b. In ongoing studies this model is used to perform virtual screening to identify novel modulators of the urate transport system enabling the development of novel therapies in pregnancy complications.

Abundance, Electron transport System (ETS) activity and respiration rates of pelagic decapods from the Benguela upwelling system during AFR258, D356 and MSM17/3

Decapods were sampled with a 1 m**2 MOCNESS (mainly upper 1000 m) in the northern Benguela Current during three cruises in December 2009, September/October 2010 and February 2011. Although pelagic decapods are abundant members of the micronekton community, information about their ecophysiology is very limited. Species-specific regional distribution limits were detected for various decapod species (e.g. Plesionika carinata, Sergestes arcticus, Pasiphaea semispinosa). Significant diel vertical migration patterns were determined for three caridean and three penaeiodean species. Biomass was variable and ranged from 23 to 2770 mg dry mass m**-2 with highest values for P. semispinosa. Fatty acid and stable isotope analyses revealed that the examined decapod species are omnivorous tocarnivorous except for the herbivorous to omnivorous species P. carinata. Calanid copepods such as Calanoides carinatus were identified as an important prey item especially for caridean species. Community consumption rates of pelagic decapods derived from respiration rates ranged from 7 mg C m**-2 d**-1 (231S) to 420 mg C m**-2 d**-1 (191S, 171S). A potential active respiratory carbon flux was calculated for migrating pelagic decapods with 4.4 mg C m**- d**-1 for the upper 200 m and with 2.6 mg C m**-2 d**-1 from the base of the euphotic zone to a depth of 600 m. Overall, pelagic decapods apparently play a more prominent role in the northern Benguela Current ecosystem than previously assumed and may exert a substantial predation impact on calanid copepods (up to 13% d**-1 of standing stock).