Biodiversity loss and turnover in alternative states in the Mediterranean Sea: a case study on meiofauna

In the Mediterranean Sea hard-bottom macroalgal meadows may switch to alternative and less-productive barrens grounds, as a result of sea urchins overgrazing. Meiofauna (and especially nematodes) represent key components of benthic ecosystems, are highly-diversified, sensitive to environmental change and anthropogenic impacts, but, so-far, have been neglected in studies on regime shifts. We report here that sedimentary organic matter contents, meiofaunal taxa richness and community composition, nematode α- and β-biodiversity vary significantly between alternative macroalgal and barren states. The observed differences are consistent in six areas spread across the Mediterranean Sea, irrespective of barren extent. Our results suggest also that the low biodiversity levels in barren states are the result of habitat loss/fragmentation, which is associated also with a lower availability of trophic resources. Furthermore, differences in meiofaunal and nematode abundance, biomass and diversity between macroalgal meadow and barren states persist when the latter is not fully formed, or consists of patches interspersed in macroalgal meadows. Since barren grounds are expanding rapidly along the Mediterranean Sea and meiofauna are a key trophic component in marine ecosystems, we suggest that the extension and persistence of barrens at the expenses of macroalgal meadows could also affect resilience of higher trophic level

The Mad Hatter’s Quip: Looking for Logic in the Independent State Legislature Theory

The Supreme Court is set to hear a case that threatens the bedrock of America’s democracy, and it is not clear how it will shake out. The cumbersomely named “Independent State Legislature Theory” is at the heart of the case Moore v. Harper, which is before the Supreme Court this term. The theory holds that state legislatures should be free from the ordinary bounds of state judicial review when engaged in matters that concern federal elections. Despite being defeated a myriad of times at the Supreme Court, the latest challenge stems from a legal battle over North Carolina’s redistricting maps. If the Court rules in favor of the theory—as some recent scholars urge them to do—then historically undemocratic state legislatures would be free to engage in all manner of devious disenfranchisement tactics, with little to no redress in state courts

Nematode biodiversity and benthic trophic state are simple tools for the assessment of the environmental quality in coastal marine ecosystems

A high biodiversity is essential to guarantee the stability and functioning of coastal marine ecosystems. In this perspective, the Marine Strategy Framework Directive provides prescriptions to maintain (or restore) marine biodiversity in order to achieve a Good Environmental Status (GES). Eutrophic conditions - as determined by the accumulation of sedimentary organic matter (OM) – are often associated with biodiversity loss, so that eutrophic conditions are often considered a pre-requisite or a proxy for degraded ecological conditions. The aim of this study was to investigate the feasibility of the combined use of benthic trophic status and nematode biodiversity as integrated indicators of the environmental status of marine coastal ecosystems. To achieve this objective, we investigated nematode species diversity and assemblage composition in three areas of the Adriatic Sea, characterised by different OM quantity and biochemical composition (as proxy of sedimentary trophic status) and affected by different levels of anthropogenic impact. We show that, on the basis of OM quantity and biochemical composition, the investigated sites can be classified from oligo- to meso-trophic, whereas the analysis of nematode biodiversity indicates that the ecological quality status (EQS) ranged from bad to moderately impacted. This result provides evidence that trophic status and environmental quality assessments are not interchangeable tools for the assessment of marine ecosystems EQS. Rather they should be considered as complementary proxies for the overall assessment of the (good) ecological status. Data reported here also indicate that the loss of benthic biodiversity, whatever the source of disturbance, may be associated to a decrease of the functional diversity (either as feeding and life strategies traits), which might have important consequences on ecosystems functioning. Our results suggest that the GES cannot be defined uniquely in terms of sedimentary trophic status, especially when many other multiples stressors can contribute to determine the overall environmental quality of the investigated ecosystems. Nematode biodiversity is highly sensitive to differences in ecological conditions at different spatial and temporal scales and it can provide reliable and complementary information for the assessment of the environmental status in marine coastal sediments

Estudio químico de Gomphrena Martiana Moquin (Familia : Amarantacea)

El objetivo de este trabajo ha sido aislar e identificarlos componentes orgánicos de Gomphrena martiana (Flia.: Amarantaceae),planta argentina conocida en la medicina folklórica principalmentepor su acción diurética. En la presente tesis se desarrollaron los siguientestemas: 1.- Introducción a la familia Amarantaceae considerandolos aspectos botánicos y fitoquímicos de la misma, y dando, en particular, una descripción del género Gomphrena. 2.- Características estructurales de los flavonoides,relaciones biosintéticas, localización y función de los mismos enel vegetal, así como acción farmacológica presentada por distintostipos de estos compuestos. 3.- Análisis detallado de los espectros de masas, 1H-RMNy 13C-RMN, utilizados en la elucidación estructural de flavonoides. 4.- Descripción de los espectros de masas de esteroles, 3-cetoesteroides α,β-insaturados y triterpenos tetracíclicos conla unidad 9:19-ciclopropano, así como su distribución en los vegetales. Los puntos 3.- y 4.- se desarrollan en detalle parafacilitar la comprensión de la discusión de los resultados obtenidosen esta tesis. 5.- Discusión de los resultados obtenidos en esta tesis,correspondientes a la caracterización de los compuestos orgánicos presentes en el extracto de éter de petróleo y etanólico dela planta mencionada. Se indicaron las técnicas separativas, especialmentecromatográficas, empleadas en las etapas de aislamiento y purificación, y se analizaron detalladamente los espectros (U.V., I.R., 1H-RMN, 13C-RMN y E.M.) y/o métodos químicos que condujeron a laidentificación de: a) 3,5-dimetoxi-6,7-metilendioxiflavona 98. b) 5,7-dihidroxi-3,6-dimetoxiflavona 100. c) 5,7-dihidroxi-6-metoxiflavona 101. d) 3,5,7-trimetoxiflavona 104. e) Hidrocarburos lineales de C29H60 a C35H72 e hidrocarburos.pertenecientes a la serie iso de C31H64 y C33H68. f) Alcoholes lineales de C24H50O a C30H62O. g) B-amirina 107. h) Ciclolaudenol 83. i) Hopeol 109. j) Colesterol 110. k) Campesterol 111. l) Estigmasterol 112. m) Sitosterol 113. n) 3,5,6,7-tetrametoxiflavona 114. ñ) 7-hidroxi-5,6-dimetoxiflavona 115. o) Colina 11. p) Betaina 9. q) Isoramnetina-3-O-robinobiósido 116. Los flavonoides 98, 100, 114 y 115 no habían sido descriptos anteriormentecomo productos naturales, por lo que fueroncomparados con testigos sintéticos o bien transformados químicamente, a fin de relacionar las distintas estructuras entre sí. Estastransformaciones permitieron obtener: r) 5-hidroxi-3-metoxi-6,7-metilendioxiflavona 99, no descriptopreviamente. s) 5,6,7-trimetoxiflavona 102. t) 5,7-diacetoxi-6-metoxiflavona 103. El flavonoide 104 que había sido descripto sólo una vezcomo producto natural, fue sintetizado a fin de confirmar su estructura. En el caso del glicósido de flavonoide 116 no existían descripcionessobre la naturaleza exacta del disacárido constituyente. Así mismo, el hecho de tener datos espectroscópicos de flavonoidesíntimamente relacionados, permitió realizar una comparaciónde los mismos para fijar pautas que facilitaran las asignacionesde señales en espectros de masas, 1H-RMNy 13C-RMN de otras agliconas de flavonoides con estructuras similares. Se propuso una posible génesis del ión m/e 69 observadoen los espectros de masas de algunos flavonoides descriptosen esta tesis, en base al estudio del espectro de masas del derivadodeuterado del compuesto 101, en el que dicho fragmento eraparticularmente intenso. Por último, se realizó un estudio quimiotaxonómico preliminarde los extractos de éter de petróleo de Gomphrena martiana, Gomphrenaboliviana y Gomphrena meyeniana y de los extractos etanólicos de Gomphrena martiana, Gomphrena boliviana, Gomphrena haenkeana, Gomphrena meyeniana y Gomphrena perennis, que permitió establecer, con los resultados obtenidos hasta el momento que las especies Gomphrena martiana y Gomphrena boliviana están íntimamente relacionadas entre sí, siendo diferentes a las restantes. Además de los compuestos mencionados anteriormente (a-q), por el estudio químico de estas especies se obtuvieron las siguientes sustancias: r) α-amirina 121. s) Δ7-colesterol 122. t) Δ7-sitosterol 123. u) Sitosterona 124. v) Ecdisterona 23. Se incluye además la descripción de los estudios efectuadossobre acción antimicrobiana y antitumoral de los extractos de éterde petróleo, etanólico y mezclas enriquecidas en los flavonoides 98, 100 y 101 de Gomphrena martiana. 6.- Parte experimental de la labor realizada, que incluye losdatos numéricos de los espectros de los distintos compuestós descriptos en esta tesis.Fil: Buschi, Carlos Alberto. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina

¿Jubilación y tiempo libre pueden convertirse en un factor de vulnerabilidad?

Por primera vez el mundo se enfrenta a un cambio demográfico tan importante, el mismo tendrá consecuencias transcendentales tanto para las naciones que lo componen, como para los individuos que lo habitan. La ciudad Autónoma de Buenos Aires tiene ya 150.000 adultos mayores de 80 años y casi un 1.000.000 en todo el país, con un total de 6.092.384 mayores de 65 años en toda la Argentina, con una proyección más elevada hacia el 2040 que casi duplicará la población infantil. Se realizó una investigación descriptiva y exploratoria para conocer el impacto de la jubilación en la calidad de vida de personas residentes en la Ciudad Autónoma de Buenos Aires y Gran Buenos Aires.A descriptive and exploratory research was conducted to know the impact of retirement on the quality of life of people living in the City of Buenos Aires and Gran Buenos Aires. The sample consists of 185 people, 103 women and 82 men, of which 57 % living in the CBA and 43 % in Gran Buenos Aires.Trabajos libres: Psicología laboral y organizacional.Facultad de Psicologí

Novel Insights on the Bacterial and Archaeal Diversity of the Panarea Shallow-Water Hydrothermal Vent Field

Current knowledge of the microbial diversity of shallow-water hydrothermal vents is still limited. Recent evidence suggests that these peculiar and heterogeneous systems might host highly diversified microbial assemblages with novel or poorly characterized lineages. In the present work, we used 16S rRNA gene metabarcoding to provide novel insights into the diversity of the bacterial and archaeal assemblages in seawater and sediments of three shallow-water hydrothermal systems of Panarea Island (Tyrrhenian Sea). The three areas were characterized by hot, cold, or intermediate temperatures and related venting activities. Microbial biodiversity in seawater largely differed from the benthic one, both in alpha-diversity (i.e., richness of amplicon sequence variants-ASVs) and in prokaryotic assemblage composition. Furthermore, at the class level, the pelagic prokaryotic assemblages were very similar among sites, whereas the benthic microbial assemblages differed markedly, reflecting the distinct features of the hydrothermal activities at the three sites we investigated. Our results show that ongoing high-temperature emissions can influence prokaryotic alpha-diversity at the seafloor, increasing turnover (beta-)diversity, and that the intermediate-temperature-venting spot that experienced a violent gas explosion 20 years ago now displays the highest benthic prokaryotic diversity. Overall, our results suggest that hydrothermal vent dynamics around Panarea Island can contribute to an increase in the local heterogeneity of physical-chemical conditions, especially at the seafloor, in turn boosting the overall microbial (gamma-)diversity of this peculiar hydrothermal system

Microbiome enrichment from contaminated marine sediments unveils novel bacterial strains for petroleum hydrocarbon and heavy metal bioremediation

Petroleum hydrocarbons and heavy metals are some of the most widespread contaminants affecting marine ecosystems, urgently needing effective and sustainable remediation solutions. Microbial-based bioremediation is gaining increasing interest as an effective, economically and environmentally sustainable strategy. Here, we hypothesized that the heavily polluted coastal area facing the Sarno River mouth, which discharges >3 tons of polycyclic aromatic hydrocarbons (PAHs) and ∼15 tons of heavy metals (HMs) into the sea annually, hosts unique microbiomes including marine bacteria useful for PAHs and HMs bioremediation. We thus enriched the microbiome of marine sediments, contextually selecting for HM-resistant bacteria. The enriched mixed bacterial culture was subjected to whole-DNA sequencing, metagenome-assembled-genomes (MAGs) annotation, and further sub-culturing to obtain the major bacterial species as pure strains. We obtained two novel isolates corresponding to the two most abundant MAGs (Alcanivorax xenomutans strain-SRM1 and Halomonas alkaliantarctica strain-SRM2), and tested their ability to degrade PAHs and remove HMs. Both strains exhibited high PAHs degradation (60–100%) and HMs removal (21–100%) yield, and we described in detail >60 genes in their MAGs to unveil the possible genetic basis for such abilities. Most promising yields (∼100%) were obtained towards naphthalene, pyrene and lead. We propose these novel bacterial strains and related genetic repertoire to be further exploited for effective bioremediation of marine environments contaminated with both PAHs and HMs

Resistance to freezing conditions of endemic Antarctic polychaetes is enhanced by cryoprotective proteins produced by their microbiome

The microbiome plays a key role in the health of all metazoans. Whether and how the microbiome favors the adaptation processes of organisms to extreme conditions, such as those of Antarctica, which are incompatible with most metazoans, is still unknown. We investigated the microbiome of three endemic and widespread species of Antarctic polychaetes: Leitoscoloplos geminus, Aphelochaeta palmeri, and Aglaophamus trissophyllus. We report here that these invertebrates contain a stable bacterial core dominated by Meiothermus and Anoxybacillus, equipped with a versatile genetic makeup and a unique portfolio of proteins useful for coping with extremely cold conditions as revealed by pangenomic and metaproteomic analyses. The close phylosymbiosis between Meiothermus and Anoxybacillus and these Antarctic polychaetes indicates a connection with their hosts that started in the past to support holobiont adaptation to the Antarctic Ocean. The wide suite of bacterial cryoprotective proteins found in Antarctic polychaetes may be useful for the development of nature-based biotechnological applications