Salinity-induced chemical,mechanical, and behavioral changes in marine microalgae

Journal of Applied Phycology - This study examines how salinity reduction triggers the response of three marine microalgae at the molecular and unicellular levels in terms of chemical, mechanical,...     

Temperature-induced response in algal cell surface properties and behaviour: an experimental approach

Journal of Applied Phycology - Microalgae are considered an accurate indicator of ecosystem perturbations induced by global climate change. The present work aims to investigate the alteration of...     

Carbonate bioformations around underwater freshwater springs in the north-eastern Adriatic Sea

Large carbonate, bryozoan-serpulid constructions, made by Pentapora fascialis and Salmacina dysteri respectively, were found around karstic freshwater springs, called vruljas, in the Senj Archipelago (Velebit Channel, Croatia). In June 2002, several sites were investigated by SCUBA divers on the rocky cliffs of Grmac and dralova at depths ranging from 19 to 32 m. Mean colony diameter decreased with increasing distance from the vruljas: in the vicinity the mean diameter was 65.8±21 cm, at 2-m distance it was 40.4±8.2. Carbonate contribution was to a great extent due to the bryozoan (5,784±1,186 gm^–2 CaCO₃) rather than to the serpulid (383±218 gm^–2 CaCO₃). P. fascialis carbonate standing stock was remarkably high if compared with data from literature for shallow carbonate producers. The bryozoan-serpulid constructions can be indicated as important, even if localised, contributions to the carbonate budget in the Adriatic Sea.     

Short and Long-Term Effects of the Angiotensin II Receptor Blocker Irbesartan on Intradialytic Central Hemodynamics: A Randomized Double-Blind Placebo-Controlled One-Year Intervention Trial (the SAFIR Study)

Background and Aim

Little is known about the tolerability of antihypertensive drugs during hemodialysis treatment. The present study evaluated the use of the angiotensin II receptor blocker (ARB) irbesartan.

Design

Randomized, double-blind, placebo-controlled, one-year intervention trial.

Setting and Participants

Eighty-two hemodialysis patients with urine output >300 mL/day and dialysis vintage <1 year.

Intervention

Irbesartan/placebo 300 mg/day for 12 months administered as add-on to antihypertensive treatment using a predialytic systolic blood pressure target of 140 mmHg in all patients.

Outcomes and Measurements

Cardiac output, stroke volume, central blood volume, total peripheral resistance, mean arterial blood pressure, and frequency of intradialytic hypotension.

Results

At baseline, the groups were similar regarding age, comorbidity, blood pressure, antihypertensive medication, ultrafiltration volume, and dialysis parameters. Over the one-year period, predialytic systolic blood pressure decreased significantly, but similarly in both groups. Mean start and mean end cardiac output, stroke volume, total peripheral resistance, heart rate, and mean arterial pressure were stable and similar in the two groups, whereas central blood volume increased slightly but similarly over time. The mean hemodynamic response observed during a dialysis session was a drop in cardiac output, in stroke volume, in mean arterial pressure, and in central blood volume, whereas heart rate increased. Total peripheral resistance did not change significantly. Overall, this pattern remained stable over time in both groups and was uninfluenced by ARB treatment. The total number of intradialytic hypotensive episodes was (placebo/ARB) 50/63 (P = 0.4). Ultrafiltration volume, left ventricular mass index, plasma albumin, and change in intradialytic total peripheral resistance were significantly associated with intradialytic hypotension in a multivariate logistic regression analysis based on baseline parameters.

Conclusion

Use of the ARB irbesartan as an add-on to other antihypertensive therapy did not significantly affect intradialytic hemodynamics, neither in short nor long-term, and no significant increase in hypotensive episodes was seen.

Trial registration

Clinicaltrials.gov NCT00791830     

Bryozoans are returning home: recolonization of freshwater ecosystems inferred from phylogenetic relationships

Bryozoans are aquatic invertebrates that inhabit all types of aquatic ecosystems. They are small animals that form large colonies by asexual budding. Colonies can reach the size of several tens of centimeters, while individual units within a colony are the size of a few millimeters. Each individual within a colony works as a separate zooid and is genetically identical to each other individual within the same colony. Most freshwater species of bryozoans belong to the Phylactolaemata class, while several species that tolerate brackish water belong to the Gymnolaemata class. Tissue samples for this study were collected in the rivers of Adriatic and Danube basin and in the wetland areas in the continental part of Croatia (Europe). Freshwater and brackish taxons of bryozoans were genetically analyzed for the purpose of creating phylogenetic relationships between freshwater and brackish taxons of the Phylactolaemata and Gymnolaemata classes and determining the role of brackish species in colonizing freshwater and marine ecosystems. Phylogenetic relationships inferred on the genes for 18S rRNA, 28S rRNA, COI, and ITS2 region confirmed Phylactolaemata bryozoans as radix bryozoan group. Phylogenetic analysis proved Phylactolaemata bryozoan's close relations with taxons from Phoronida phylum as well as the separation of the Lophopodidae family from other families within the Plumatellida genus. Comparative analysis of existing knowledge about the phylogeny of bryozoans and the expansion of known evolutionary hypotheses is proposed with the model of settlement of marine and freshwater ecosystems by the bryozoans group during their evolutionary past. In this case study, brackish bryozoan taxons represent a link for this ecological phylogenetic hypothesis. Comparison of brackish bryozoan species Lophopus crystallinus and Conopeum seurati confirmed a dual colonization of freshwater ecosystems throughout evolution of this group of animals.     

Hyposalinity induces significant polar lipid remodeling in the marine microalga Dunaliella tertiolecta (Chlorophyceae)

Journal of Applied Phycology - Marine microalgae often live in a fluctuating environment including a decrease in salinity caused by global warming induced sea ice melting and freshwater inflows....