Spatio-temporal Phytoplankton Variability in two Himalayn Lacustrine Ecosystems

Jabbari M, Salahi M, Ghorbani R. 2018. Spatio-temporal influence of physicochemical parameters on phytoplankton assemblage in coastal brackish lagoon: Gomishan Lagoon, Caspian Sea, Iran. Biodiversitas 19: 2020-2027. The objective of this study was to determine the spatiotemporal distribution pattern of phytoplankton assemblage due to physico-chemical heterogeneity in coastal brackish lagoon of Gomishan. An inter-annual cycle of sampling period (April 2014-March 2015) and spatially stratified random sampling were established to examine 24 spatiotemporal scenarios. Water samples were preserved in 1 and 0.5 liter dark Polythene bottles from each station for assessing plankton community and chlorophyll a, respectively. The applied multivariate approach including hierarchical cluster analysis for (dis)similarity test of environmental factors, principle component analysis (PCA) and canonical correspondence analysis (CCA) was used to illustrate the pattern of phytoplankton variability in relation to environmental characteristics. The results showed that mean salinity, temperature, pH, total nitrogen, phosphorus, silica, turbidity, and electrical conductivity (EC) were 22.8±5.9 (ppt), 23.4° C, 8.18, 2.49 (mg.l-1), 0.258 (mg.l-1), 3.39 (mg.l-1), 42.12 (NTU), and 3.78 (dS/m3), respectively. Scenarios S5AT, S5W, S6W, S6AT were distinguished from other scenarios with more than 90% similarity, subsequently S1SU and S5SU with about 80% similarity. Inter-annual mean density of total phytoplankton (cell.l-1) was 2.45×106, whereas in northern sector it was constant with only a peak in June, but in southern sector it was more tolerant, so in April it tended to increase with a peak (7.2×106) in July which was the maximum density over the year. The phytoplankton assemblage of the lagoon comprised 47 species from 5 different classes including Bacillariophyta, Pyrrophyta, Chlorophyta, Cyanophyta, and Euglenophyta.

Download Full-text

E3 ubiquitin ligases

Essays in Biochemistry ◽

10.1042/bse0410015 ◽

2005 ◽

Vol 41 ◽

pp. 15-30 ◽

Cited By ~ 123

Author(s):

Helen C. Ardley ◽

Philip A. Robinson

Keyword(s):

Protein Complexes ◽

Loss Of Function ◽

Direct Role ◽

Cellular Processes ◽

Substrate Protein ◽

Protein Ubiquitination ◽

C Terminus ◽

Full Complement ◽

Spatio Temporal ◽

Eukaryotic Organisms

The selectivity of the ubiquitin–26 S proteasome system (UPS) for a particular substrate protein relies on the interaction between a ubiquitin-conjugating enzyme (E2, of which a cell contains relatively few) and a ubiquitin–protein ligase (E3, of which there are possibly hundreds). Post-translational modifications of the protein substrate, such as phosphorylation or hydroxylation, are often required prior to its selection. In this way, the precise spatio-temporal targeting and degradation of a given substrate can be achieved. The E3s are a large, diverse group of proteins, characterized by one of several defining motifs. These include a HECT (homologous to E6-associated protein C-terminus), RING (really interesting new gene) or U-box (a modified RING motif without the full complement of Zn2+-binding ligands) domain. Whereas HECT E3s have a direct role in catalysis during ubiquitination, RING and U-box E3s facilitate protein ubiquitination. These latter two E3 types act as adaptor-like molecules. They bring an E2 and a substrate into sufficiently close proximity to promote the substrate's ubiquitination. Although many RING-type E3s, such as MDM2 (murine double minute clone 2 oncoprotein) and c-Cbl, can apparently act alone, others are found as components of much larger multi-protein complexes, such as the anaphase-promoting complex. Taken together, these multifaceted properties and interactions enable E3s to provide a powerful, and specific, mechanism for protein clearance within all cells of eukaryotic organisms. The importance of E3s is highlighted by the number of normal cellular processes they regulate, and the number of diseases associated with their loss of function or inappropriate targeting.

Download Full-text

Elucidating cyclic AMP signaling in subcellular domains with optogenetic tools and fluorescent biosensors

Biochemical Society Transactions ◽

10.1042/bst20190246 ◽

2019 ◽

Vol 47 (6) ◽

pp. 1733-1747 ◽

Cited By ~ 3

Author(s):

Christina Klausen ◽

Fabian Kaiser ◽

Birthe Stüven ◽

Jan N. Hansen ◽

Dagmar Wachten

Keyword(s):

Cyclic Amp ◽

Adenosine Monophosphate ◽

Adenylyl Cyclases ◽

Temporal Precision ◽

Fluorescent Biosensors ◽

Subcellular Domains ◽

Spatio Temporal ◽

Hydrolysis Of ◽

Shed Light ◽

Cyclic Amp Signaling

The second messenger 3′,5′-cyclic nucleoside adenosine monophosphate (cAMP) plays a key role in signal transduction across prokaryotes and eukaryotes. Cyclic AMP signaling is compartmentalized into microdomains to fulfil specific functions. To define the function of cAMP within these microdomains, signaling needs to be analyzed with spatio-temporal precision. To this end, optogenetic approaches and genetically encoded fluorescent biosensors are particularly well suited. Synthesis and hydrolysis of cAMP can be directly manipulated by photoactivated adenylyl cyclases (PACs) and light-regulated phosphodiesterases (PDEs), respectively. In addition, many biosensors have been designed to spatially and temporarily resolve cAMP dynamics in the cell. This review provides an overview about optogenetic tools and biosensors to shed light on the subcellular organization of cAMP signaling.

Download Full-text