scholarly journals A biodiversity survey on the planktonic protistan grazers of the Gulf of Naples (Italy)

2021 ◽  
Vol 12 (2) ◽  
Author(s):  
Gabriele Del Gaizo ◽  
Luca Russo ◽  
Maria Abagnale ◽  
Angela Buondonno ◽  
Marta Furia ◽  
...  
Keyword(s):  
Light Availability ◽  
Taxonomic Composition ◽  
Primary Producers ◽  
Biodiversity Survey ◽  
Gulf Of Naples ◽  
Unicellular Eukaryotes ◽  
Planktonic Food ◽  
Multicellular Organisms ◽  
Plankton Communities ◽  
Made In

Plankton communities include both unicellular and multicellular organisms. An important unicellular component is represented by those protists (i.e., unicellular eukaryotes) that are non-strictly autotrophic organisms and consume bacteria and other protists. These organisms are an important link between primary producers and metazoans and are usually known as microzooplankton, protozooplankton, or mixoplankton, as many of them couple phagotrophic and photoautotrophic behaviours. Herein we report on the diversity of these organisms sampled at two sampling sites (coastal and offshore stations), at two depths (0 and 10 m), in the Gulf of Naples during the early autumn of 2020. Despite efforts to list plankton biodiversity of primary producers and metazoan grazers made in this area so far, protistan grazers are still poorly investigated and previous information date back to decades ago. Our survey identified dinoflagellates and oligotrich ciliates as the most abundant groups, while tintinnids were less quantitatively relevant. The taxonomic composition in samples investigated herein remarked that reported by previous studies, with the sole exception of the tintinnid Ascampbeliella armilla, which was never reported before. A coastal-offshore gradient in the taxonomical composition of protistan grazers was also observed, with some species more abundant within coastal waters and other better thriving in offshore ones. Surface and sub-surface communities also differed in terms of species composition, with the deeper communities in the two sites being more similar reciprocally than with communities at the surface. These differences were associated with distinct environmental conditions, such as light availability, as well with the standing feeding environment, arising potential implications in the functioning of the planktonic food web at the local scale.

scholarly journals Effects of thermocline deepening on lake plankton communities

2011 ◽  
Vol 68 (2) ◽  
pp. 260-276 ◽  
Author(s):  
Ariane Cantin ◽  
Beatrix E. Beisner ◽  
John M. Gunn ◽  
Yves T. Prairie ◽  
Jennifer G. Winter
Keyword(s):  
Taxonomic Composition ◽  
Zooplankton Biomass ◽  
Phytoplankton Production ◽  
Thermocline Depth ◽  
Turbulent Environments ◽  
Planktonic Food ◽  
Basin Scale ◽  
Zooplankton Communities ◽  
The Vertical Distribution ◽  
Plankton Communities

Theory predicts, and some evidence demonstrates that in lakes, the depth of the thermocline can have a large structural influence on the spatial distribution, and strongly influences the composition of plankton communities. However, experimental assessments of responses of the planktonic food web to thermocline depth have not yet been done at the whole-basin scale. We conducted an experiment wherein we artificially lowered the thermocline in an isolated basin of a three-basin lake, maintaining another isolated basin as a control. The vertical distribution and taxonomic composition of both phytoplankton and zooplankton were monitored throughout the summer months. Greater phytoplankton production, especially in the epilimnion, attributable mainly to increases in the chlorophytes was observed with thermocline deepening, but at the deepest thermoclines, production was limited. Total zooplankton biomass was unaffected by thermocline depth, suggesting top-down control by predators. Zooplankton biomass peaks were less pronounced in the manipulated basin, but tended to follow the thermocline whether at its normal position or as it was deepened. Zooplankton composition was significantly altered by large increases in densities of predatory cyclopoid copepods and rotifers; taxa commonly found in turbulent environments. Overall, both phytoplankton and zooplankton communities demonstrated important shifts in structure and composition in response to thermocline deepening.

The Qualitative and Quantitative Distribution of Plankton in the Strait of Georgia in Relation to Certain Oceanographic Factors

1957 ◽  
Vol 14 (4) ◽  
pp. 521-552 ◽  
Author(s):  
Joseph Eugène Henri Légaré
Keyword(s):  
Salinity Gradient ◽  
General Distribution ◽  
Fraser River ◽  
Strait Of Georgia ◽  
Quantitative Distribution ◽  
Qualitative And Quantitative ◽  
Chemical Factors ◽  
Physical And Chemical ◽  
Plankton Communities ◽  
Made In

In order to gain some picture of the seasonal variations in the plankton communities two cruises were made in the Strait of Georgia, one in June 1955, and the other in November 1955; 165 plankton collections were taken, also surface temperatures.The correlation of these data have resulted in a number of conclusions concerning the distribution of plankton in the Strait of Georgia. The chief factor affecting the general distribution of plankton is the salinity gradient. The inflow of fresh water from the Fraser River forms zones of varying properties, and leads to the development of different plankton communities. The extent to which physical and chemical factors may determine the presence or absence of certain organisms from the zones described is discussed.

scholarly journals Current and Emerging Biomarkers of Cell Death in Human Disease

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Kongning Li ◽  
Deng Wu ◽  
Xi Chen ◽  
Ting Zhang ◽  
Lu Zhang ◽  
...  
Keyword(s):  
Cell Death ◽  
Molecular Mechanisms ◽  
Research Area ◽  
Human Diseases ◽  
Mitotic Catastrophe ◽  
Regulated Necrosis ◽  
Early Diagnose ◽  
Multicellular Organisms ◽  
The Relationship ◽  
Made In

Cell death is a critical biological process, serving many important functions within multicellular organisms. Aberrations in cell death can contribute to the pathology of human diseases. Significant progress made in the research area enormously speeds up our understanding of the biochemical and molecular mechanisms of cell death. According to the distinct morphological and biochemical characteristics, cell death can be triggered by extrinsic or intrinsic apoptosis, regulated necrosis, autophagic cell death, and mitotic catastrophe. Nevertheless, the realization that all of these efforts seek to pursue an effective treatment and cure for the disease has spurred a significant interest in the development of promising biomarkers of cell death to early diagnose disease and accurately predict disease progression and outcome. In this review, we summarize recent knowledge about cell death, survey current and emerging biomarkers of cell death, and discuss the relationship with human diseases.

scholarly journals Light availability in the coastal ocean: impact on the distribution of benthic photosynthetic organisms and contribution to primary production

2006 ◽  
Vol 3 (4) ◽  
pp. 895-959 ◽  
Author(s):  
J.-P. Gattuso ◽  
B. Gentili ◽  
C. M. Duarte ◽  
J. A. Kleypas ◽  
J. J. Middelburg ◽  
...  
Keyword(s):  
Primary Production ◽  
Surface Area ◽  
Coastal Zone ◽  
Benthic Communities ◽  
Light Availability ◽  
Coastal Ocean ◽  
Shelf Area ◽  
Primary Producers ◽  
Benthic Primary Production ◽  
Photosynthetic Organisms

Abstract. One of the major features of the coastal zone is that part of its sea floor receives a significant amount of sunlight and can therefore sustain benthic primary production by seagrasses, macroalgae, microphytobenthos and corals. However, the contribution of benthic communities to the primary production of the global coastal ocean is not known, partly because the surface area where benthic primary production can proceed is poorly quantified. Here, we use a new analysis of satellite (SeaWiFS) data collected between 1998 and 2003 to estimate, for the first time at a nearly global scale, the irradiance reaching the bottom of the coastal ocean. The following cumulative functions provide the percentage of the surface of the coastal zone receiving an irradiance greater than Ez: PaNon-polar=28.80−16.69 log10(Ez)+0.84 log102(Ez)+0.83 log103(Ez) PaArctic=16.01−15.67 log10(Ez)+2.03 log102(Ez)+1.00 log103(Ez) Data on the constraint of light availability on the major benthic primary producers and net primary production are reviewed. Some photosynthetic organisms can grow deeper than the nominal bottom limit of the coastal ocean (200 m). The minimum irradiance required varies from 0.4 to 5.1 mol photons m−2 d−1 depending on the group considered. The daily compensation irradiance of benthic communities ranges from 0.24 to 4.4 mol photons m−2 d−1. Data on benthic irradiance and light requirements are combined to estimate the surface area of the coastal ocean where (1) light does not limit the distribution of primary producers and (2) net community production (NCP, the balance between gross primary production and respiration) is positive. Positive benthic NCP can occur over 37% of the global shelf area. The limitations of this approach, related to the spatial resolution of the satellite data, the parameterization used to convert reflectance data to irradiance, and the relatively limited biological information available, are discussed.

Juvenile tree growth in relation to light availability in second-growth tropical rain forests

2006 ◽  
Vol 22 (2) ◽  
pp. 223-226 ◽  
Author(s):  
Mary Beth Palomaki ◽  
Robin L. Chazdon ◽  
J. Pablo Arroyo ◽  
Susan G. Letcher
Keyword(s):  
Tropical Forests ◽  
Light Availability ◽  
Tree Seedlings ◽  
Tropical Rain Forests ◽  
Annual Increment ◽  
Growth And Survival ◽  
Second Growth ◽  
Direct Measurements ◽  
Crown Shape ◽  
Made In

Light is a key environmental factor limiting growth and survival of trees in the subcanopy of wet tropical forests (Davies 2001, Thomas 1996). Light availability varies both vertically and horizontally and affects tree height, crown shape and tree architecture (Bongers & Sterck 1998, Sterck & Bongers 2001, Sterck et al. 1999) in addition to growth and survival (Clark & Clark 1992, 2001). Although many studies of tree seedlings and saplings have shown that growth varies significantly with light availability in tropical wet forests (Clark et al. 1993, Iriarte & Chazdon 2005, King 1991, Kohyama 1991, Montgomery & Chazdon 2002, Oberbauer et al. 1988, 1993; Poorter & Werger 1999, Sterck et al. 1999, Welden et al. 1991), few studies have examined these relationships in size classes above 5 cm dbh (Sterck 1999). King et al. (2005) found that annual increment growth of trees in the 8–20-cm dbh size class in two Asian forests was positively dependent on an index of crown light interception, but no direct measurements of light availability were taken in this study. Due to logistical challenges, few direct measurements of light environments above tree crowns have been made in tropical forests (Sterck & Bongers 2001). To our knowledge, no measurements have been made in second-growth forests.

scholarly journals The evolution of organellar metabolism in unicellular eukaryotes

2010 ◽  
Vol 365 (1541) ◽  
pp. 693-698 ◽  
Author(s):  
Michael L. Ginger ◽  
Geoffrey I. McFadden ◽  
Paul A. M. Michels
Keyword(s):  
Drug Targets ◽  
Oxygenic Photosynthesis ◽  
Geological Time ◽  
Unicellular Eukaryotes ◽  
Niche Adaptation ◽  
History Of ◽  
Critical Insight ◽  
Multicellular Organisms ◽  
Gradual Transformation ◽  
Insight Into

Metabolic innovation has facilitated the radiation of microbes into almost every niche environment on the Earth, and over geological time scales transformed the planet on which we live. A notable example of innovation is the evolution of oxygenic photosynthesis which was a prelude to the gradual transformation of an anoxic Earth into a world with oxygenated oceans and an oxygen-rich atmosphere capable of supporting complex multicellular organisms. The influence of microbial innovation on the Earth's history and the timing of pivotal events have been addressed in other recent themed editions of Philosophical Transactions of Royal Society B ( Cavalier-Smith et al . 2006 ; Bendall et al . 2008 ). In this issue, our contributors provide a timely history of metabolic innovation and adaptation within unicellular eukaryotes. In eukaryotes, diverse metabolic portfolios are compartmentalized across multiple membrane-bounded compartments (or organelles). However, as a consequence of pathway retargeting, organelle degeneration or novel endosymbiotic associations, the metabolic repertoires of protists often differ extensively from classic textbook descriptions of intermediary metabolism. These differences are often important in the context of niche adaptation or the structure of microbial communities. Fundamentally interesting in its own right, the biochemical, cell biological and phylogenomic investigation of organellar metabolism also has wider relevance. For instance, in some pathogens, notably those causing some of the most significant tropical diseases, including malaria, unusual organellar metabolism provides important new drug targets. Moreover, the study of organellar metabolism in protists continues to provide critical insight into our understanding of eukaryotic evolution.

scholarly journals Trypanosome Prereplication Machinery Contains a Single Functional Orc1/Cdc6 Protein, Which Is Typical of Archaea

2009 ◽  
Vol 8 (10) ◽  
pp. 1592-1603 ◽  
Author(s):  
Patrícia Diogo de Melo Godoy ◽  
Luis Antonio Nogueira-Junior ◽  
Lisvane S. Paes ◽  
Alberto Cornejo ◽  
Rafael Miyazawa Martins ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Cycle ◽  
Rna Interference ◽  
Trypanosoma Brucei ◽  
Replication Origin ◽  
Origin Recognition Complex ◽  
Gene Encoding ◽  
Unicellular Eukaryotes ◽  
Entire Cell ◽  
Multicellular Organisms

ABSTRACT In unicellular eukaryotes, such as Saccharomyces cerevisiae, and in multicellular organisms, the replication origin is recognized by the heterohexamer origin recognition complex (ORC) containing six proteins, Orc1 to Orc6, while in members of the domain Archaea, the replication origin is recognized by just one protein, Orc1/Cdc6; the sequence of Orc1/Cdc6 is highly related to those of Orc1 and Cdc6. Similar to Archaea, trypanosomatid genomes contain only one gene encoding a protein named Orc1. Since trypanosome Orc1 is also homologous to Cdc6, in this study we named the Orc1 protein from trypanosomes Orc1/Cdc6. Here we show that the recombinant Orc1/Cdc6 from Trypanosoma cruzi (TcOrc1/Cdc6) and from Trypanosoma brucei (TbOrc1/Cdc6) present ATPase activity, typical of prereplication machinery components. Also, TcOrc1/Cdc6 and TbOrc1/Cdc6 replaced yeast Cdc6 but not Orc1 in a phenotypic complementation assay. The induction of Orc1/Cdc6 silencing by RNA interference in T. brucei resulted in enucleated cells, strongly suggesting the involvement of Orc1/Cdc6 in DNA replication. Orc1/Cdc6 is expressed during the entire cell cycle in the nuclei of trypanosomes, remaining associated with chromatin in all stages of the cell cycle. These results allowed us to conclude that Orc1/Cdc6 is indeed a member of the trypanosome prereplication machinery and point out that trypanosomes carry a prereplication machinery that is less complex than other eukaryotes and closer to archaea.

scholarly journals Identifying drivers of microbial community composition associated with aquatic primary producers: metagenomic analysis of cyanobacterial cultures

2020 ◽  
Vol 2 (7A) ◽  
Author(s):  
David Green ◽  
Cecilia Rad-Menendez ◽  
Frederik De Boever
Keyword(s):  
Community Composition ◽  
Life Support ◽  
Heterotrophic Bacteria ◽  
Microbial Community Composition ◽  
Culture Collection ◽  
Taxonomic Composition ◽  
Metagenomic Analysis ◽  
Primary Producers ◽  
Functional Variation ◽  
Core Microbiome

The energy derived from aquatic primary production is fundamental to driving Earth’s life support systems – but they don’t achieve all this by themselves. Heterotrophic bacteria found in the photic zones of aquatic environments have a fundamental role in this too. Our group’s interest is in understanding how heterotrophs help autotrophs: who in these communities are important, and how and why they are important. Answering this is important in both natural and manmade environments so we can model these environments, and as appropriate, manipulate them, such as applying designer microbiomes to aid industrialisation of algal cultivation. Metagenomic analysis of 31 marine and freshwater cyanobacterial cultures from the Culture Collection of Algae & Protozoa resulted in assembly of >400 bacterial metagenomes (MAGs) with ca. 14 unique MAGs per culture. Community composition was clearly partitioned by salinity as a driver but collectively niche accounted for most community taxonomic variation. No universal core microbiome was identified, but taxonomic composition of marine cultures bore notable similarities to marine eukaryotic algal communities and to a natural cyanobacterial mat community found next to a northern Chilean geyser. Stable taxonomic associations imply that these taxa may have functional importance to their algal host. Functional analysis of the MAGs is underway and we will test whether the relative taxonomic variability contrasts with low functional variation between communities. If true, this implies that primary producers drive community assembly in a functionally predictable way, and that function, not taxonomy, is the more important parameter to understand.

scholarly journals INTERANNUAL DYNAMICS OF PLANKTON COMMUNITIES IN THE CHANNEL SECTIONS OF THE KUIBYSHEV RESERVOIR

2021 ◽  
Vol 24 (2-3) ◽  
pp. 112-115
Author(s):  
M.A. Gvozdareva ◽  
O.S. Lyubina ◽  
A.V. Melnikova ◽  
L.G. Grechukhina
Keyword(s):  
Taxonomic Diversity ◽  
Taxonomic Composition ◽  
Kuibyshev Reservoir ◽  
Biological Studies ◽  
Interannual Dynamics ◽  
Quantitative Indicators ◽  
Plankton Communities

Based on the materials of hydro-biological studies in the Volga part of the Kuibyshev reservoir in 2018 and 2019, the authors evaluated changes in the quantitative indicators and taxonomic composition of phytoplankton and zooplankton. According to the results of the study, it was revealed that in 2019 the taxonomic diversity increased, but the abundance and biomass indices of phytoplankton decreased, while zooplankton decreased only in its abundance.

scholarly journals Seasonal Dynamic of CDOM in a Shelf Site of the South-Eastern Ligurian Sea (Western Mediterranean)

2020 ◽  
Vol 8 (9) ◽  
pp. 703
Author(s):  
Luca Massi ◽  
Laura Frittitta ◽  
Chiara Melillo ◽  
Francesca Polonelli ◽  
Veronica Bianchi ◽  
...  
Keyword(s):  
Optical Properties ◽  
Organic Carbon ◽  
Phytoplankton Biomass ◽  
Light Availability ◽  
Western Mediterranean ◽  
Taxonomic Composition ◽  
Seasonal Dynamic ◽  
Ligurian Sea ◽  
Positive Correlations ◽  
High Level

Chromophoric dissolved organic matter (CDOM) is the fraction of the Dissolved Organic Carbon (DOC) mainly absorbing UV and blue radiation, influencing water optical properties, light availability for primary production, and water-leaving radiance. In open seas, phytoplankton is the main source of organic carbon and CDOM. Despite this, the direct or indirect phytoplankton role in CDOM production is not yet fully clarified. From studies about the relationship between CDOM and phytoplankton biomass as Chlorophyll a (Chl) in the epipelagic layer, positive correlations have been highlighted with regional differences and high levels of variability. Seven years of seasonal dynamic and vertical distribution of CDOM in the Ligurian Sea continental shelf waters have been analyzed in order to evidence the main environmental and/or biological factors determining CDOM dynamic, focusing on the CDOM/Chl relationship. CDOM optical properties (absorption at 440 nm, aCDOM (440), and spectral slope, S) allowed to distinguish different pools and to debate their origin. Four different pools were characterized and two of them were directly or indirectly related to phytoplankton biomass and taxonomic composition. Nevertheless, CDOM/Chl confirm a high level of variability These findings suggest some inputs to improve Mediterranean satellite estimates of Chl and CDOM, such as the seasonal differentiation of optical properties, especially S and CDOM/Chl relationships.

Sign in / Sign up

Export Citation Format

Share Document