Taxonomical and ecological analysis of epiphytic diatom communities on Gelidiacean (Rhodophyta) species from Gran Canaria (Canary Islands

In the present study we aim to describe the diatom communities associated to some Gelidiacean species (Rodophyta) from Gran Canaria (Canary Islands) considering their seasonal and spatial variability, in terms of abundance, biomass and community structure. Five Gelidiacean species (Gelidium arbuscula, Gelidium canariense, Gelidium pusillum, Pterocladiella capillacea e Pterocladiella melanoidea) has been collected in different coastal localities of Gran Canaria Island (Boccabarranco (Galdar), Agaete e Quintanilla (Bañaderos) during winter and summer season 2007-2008. Gelidium arbuscula, G. canariense e P. capillacea appeared distributed in clumps consisting of several ramets; thalli of G. pusillum e P. melaoidea looks liked to small carpet adhering to rocks. Sampled ramets were cut in a apical, central and basal fragment except in the case of G. pusillum e P. melanoidea for their reduced size (about 1cm). In order to preserve the integrity of the epiphytic diatom communities and to analyze them at Scanning Electron Microscope, ramets were fixed with glutaraldehyde 2.5% in filtered seawater and placed on a polycarbonate filter in a ―Swinnex‖ filtration apparatus (Millipore). A second filter was placed over the first to form a sandwich in which the sample was trapped. A dehydration and Critical Point Dryer treatment were respectively carried out by directly immersing the Swinnex into specific containers in alcohol at increasing alcoholic strength and finally in a Critical Point Dryer. At the end of this treatments, each fragment was placed on a stub and covered with gold-palladium to be observed using SEM. Total abundances of epiphytic diatoms in all Gelidiacean species studied were low in both the sampling seasons ranging from 200-480 cell/mm2 in winter to 150-300 cell/mm2 in Summer. Spatial distribution of epiphytic diatoms communities showed a marked increasing gradient form the basal to the apical part of the ramets. Considering the growth forms of diatom species, adnate forms (Amphora and Cocconeis spp.) were distributed mainly in the basal and central part of ramets whereas erect forms (mainly Grammatophora, Licmophora, and Achnantes spp.) were mainly distributed in the apical part of the colonies. Motile species were rarely found without showing a clear distribution pattern in the three portion of the ramets. Adnate diatoms were more abundant on those Gelidiaceae having harder, microstructurally complex and ramified thalli respect than with soft and smooth ones. This is due to the presence, in the former, of an higher number of microenvironments to which the adnate diatoms can adhere using their entire valve faces. Erected diatom species were less affected by these constrains since their adhesion to the substrate was mediated by mucilage pads or peduncles

Biodiversity and spatio-temporal variation of epiphytic diatom assemblage on five Gelidiales (Rhodophyta) from Gran Canaria (Canary Islands, Spain)

The composition and patterns of spatial and season variability of epiphytic diatom assemblages of five intertidal species of Gelidiales (Rhodophyta) from three sampling sites off Gran Canaria (Canary Islands, Atlantic Ocean) were investigated during summer (2007) and winter (2008) seasons using scanning electron microscopy (SEM). Dominant species included Cocconeis scutellum var. scutellum, C. scutellum var. posidoniae, Grammatophora oceanica, Lichmophora eherembergi, Navicula sp. and Tabularia fasciculata and these represented 78% of the total diatom assemblage on Gelidiales. Eight of the diatom taxa, Cocconeis maxima, Amphicocconeis debesii, Cocconeis convexa, C. neothumensis var. marina, C. scutellum var. scutellum, C. scutellum var. posidoniae, Gomphonemopsis obscura and Pseudohimantidium pacificum, found in the present study represent new records for the Canary Archipelago. These species showed two distinct patterns of zonation, one in relation to their position at the intertidal area and the other relative to position on the host thalli. Although the vertical distribution of host thalli at the intertidal zone was important when considering the assemblage structure of epiphytic diatoms, the results showed that the cell abundance distribution changed more significantly when considering season rather than spatial distribution. Moreover, even though morphology of host thalli was not a determining factor, their aggregation mode had a significant influence on the abundance and distribution of microalgae. Finally, considering the growth forms of diatom communities, adnate diatoms were more abundant in turf than in clump species

Mood Disorder in Cancer Patients Undergoing Radiotherapy During the COVID-19 Outbreak

Introduction: Novel coronavirus (COVID-19) is having a devastating psychological impact on patients, especially patients with cancer. This work aims to evaluate mood disorders of cancer patients undergoing radiation therapy during COVID-19 in comparison with cancer patients who underwent radiation therapy in 2019. Materials and Methods: We included all the patients undergoing radiation therapy at our department in two-time points (once a week for a month in May 2019) and during the COVID-19 outbreak (in April 2020). All the patients were asked to fulfill a validated questionnaire (STAI-Y1, State trait anxiety inventory scale), the Symptom Distress thermometer (SDT) (from 0 to 10 score), and the Beck Depression Inventory v.2 (BDI-2). We took into account the COVID-19 outbreak and also sex, age, week of radiation treatment, and disease. Results: We included 458 patients (220 males and 238 females), with a median age of 64 years. STAI-Y1 median score was 40 (mean 41,3, range 19–79), whereas the median score of SDT was five and BDI-2 median score was 11. STAI-Y1, SDT, and BDI-2 were significantly correlated with the COVID-19 outbreak (p < 0,001 for all the tests), sex (p: 0,016 for STAI-Y1, p < 0.001 for SDT, p:0.013 for BDI-2), week of treatment (p: 0.012 for STAI-Y1 and p: 0.031 for SDT), and disease (p:0.015 for STAI-Y1, p < 0.001 for SDT and p:0.020 for BDI-2). Conclusions: The prevalence of mood disorders in patients undergoing radiation therapy is higher than expected and even higher during the COVID-19 outbreak. These measurements could be useful as a baseline to start medical humanities programs to decrease these scores