A phylogenetic study of krill (Crustacea: Euphausiacea) reveals new taxa and co-evolution of morphological characters

The first comprehensive phylogenetic study of Euphausiacea (all 86 valid species) is presented. It is based on four molecular markers and 168 morphological characters (including 58 characters of the petasma). Phylogenetic analyses support the monophyly and robustness of the families Bentheuphausidae and Euphausiidae and reveal three major clades for which we erect three new subfamilies: Thysanopodinae, Euphausiinae and Nematoscelinae. All genus-level clades are statistically supported (except Thysanopoda in molecular analyses), deeply nested within the subfamily-level clades, and encompass 14 new species groups. Copulatory structures have a major impact on tree topology in the morphological analysis, the removal of which resulted in only half the number of supported clades and genera. We revealed three groups of morphological characters, which are probably coupled with the same biological role and thus interlinked evolutionarily: (i) antennular peduncle and petasma (copulation); (ii) eyes and anterior thoracopods (feeding); and (iii) shape of carapace and pleon (defence). We analysed the evolutionary pathways of the clades into main oceanic biotopes and compared them with morphological adaptations most likely to be coupled with this process.     

Formation of complexes of ascorbic acid and biological ligands

Ascorbic acid has wide usage in medical practice for treatment some diseases caused by degeneration of connective tissue. Ascorbic acid has strong reduce properties. This article is dedicated to investigating complexation properties of ascorbic acid with components of biomembrans-bioligands: the most widespread aminoacids of connective tissue, phosphatidylholine, ATP, calcium salts, proteins. The investigations realised give the opportunity to make the conclusion that ascorbic acid has some complexation properties with different bioligands. But the stability of these complex products is different. And these stability variationes are described in this article.     

Eukaryotic diversity associated with carbonates and fluid-seawater interface in Lost City hydrothermal field

Lost City is a unique off-axis hydrothermal vent field characterized by highly alkaline and relatively low-temperature fluids that harbours huge carbonate chimneys. We have carried out a molecular survey based on 18S rDNA sequences of the eukaryotic communities associated with fluid-seawater interfaces and with carbonates from venting areas and the chimney wall. Our study reveals a variety of lineages belonging to eight major taxa: Metazoa, Fungi, Heterokonta (Stramenopiles), Alveolata, Radiolaria, Cercozoa, Heterolobosea and Euglenozoa. We detected one fungal lineage that appears to be widespread in hydrothermal systems both submarine and continental. Alveolates were the most abundant and diverse group in Lost City samples, although their distribution was very different in carbonate, where ciliates dominated, and in fluid-seawater libraries, where dinoflagellates, Group I and Group II (Syndiniales) marine alveolates were profuse. Similarly, Euglenozoa also displayed a differential distribution, kinetoplastids being present on carbonates and a novel group of diplonemids so far exclusively observed in the deep sea being dominant in fluid-seawater libraries. Protist lineages identified in this ecosystem likely correspond to grazers, decomposers and parasites, playing key roles in the food web of the Lost City ecosystem.     

Activation of the Shoulder Belt and Shoulder Muscles of Humans Related to Different Rates of Generation of Two-Joint Efforts by the Forearm

We studied coordination of central motor commands (CMCs) coming to the muscles that flex and extend the shoulder and elbow joints in the course of generation of voluntary isometric efforts of different directions by the forearm. Dependences of the characteristics of these commands on the direction of the effort and rate of its generation were analyzed. Amplitudes of rectified and averaged EMGs recorded from a number of shoulder belt and shoulder muscles were considered correlates of the CMC intensity. The development of the effort of a given direction and rate of rise was realized in the horizontal-plane operational space; the arm position corresponded to the 30 deg angle in the shoulder joint (external angle with respect to the frontal plane) and 90 deg angle in the elbow joint. We plotted sector diagrams of the relative changes in the level of dynamic and stationary phases of EMG activity of the studied muscles for the entire set of directions of the efforts generated with different rates of rise. In the course of formation of rapid two-joint isometric efforts, realization of nonsynergic motor tasks (extension of one joint and flexion of another one, and vice versa) required significant activation of muscles of different functional directions for both joints. Time organization of EMG activity of extensors and flexors of the shoulder and elbow joints related to the maximum and relatively rapid generation of the effort (rise time 0.12 to 0.13 and 0.25 sec, respectively) was rather complex and included dynamic and stationary phases. With these time parameters of generation of the efforts (both flexion and extension), the appearance at the stationary effort of 40 N was controlled based on coordinated interaction of dynamic phases of the activation of agonistic and antagonistic muscles. It is concluded that CMCs coming to extensors and flexors of both joints upon generation of rapid isometric efforts are rather similar in their parameters to those under conditions of realization of the forearm movements in the space in an isotonic mode.     

Three-Dimensional Representation of Equilibrium Joint Torques in Two-Joint Movements of the Upper Limb

Neurophysiology - In this theoretical study, two-joint equilibrium muscle contractions were simulated to determine the end-point forces created by the hand of the human right upper limb within the...     

Prediction of the three-dimensional structure of aflatoxin of Aspergillus flavus by homology modelling

Aflatoxins are polyketide-derived secondary metabolites produced by Aspergillus spp. The toxic effects of aflatoxins have adverse consequences for human health and agricultural economics. The aflR gene, a regulatory gene for aflatoxin biosynthesis, encodes a protein containing a zinc-finger DNA-binding motif. AFLR-Protein three-dimensional model was generated using Robetta server. The modeled AFLR-Protein was further optimization and validation using Rampage. In the simulations, we monitored the backbone atoms and the C-α-helix of the modeled protein. The low RMSD and the simulation time indicate that, as expected, the 3D structural model of AFLR-protein represents a stable folding conformation. This study paves the way for generating computer molecular models for proteins whose crystal structures are not available and which would aid in detailed molecular mechanism of inhibition of aflatoxin.     

Phylogeny and taxonomy of the enigmatic genus Petalidium (Decapoda,Sergestidae), with biological remarks

Petalidium (Decapoda: Dendrobranchiata: Sergestidae) is one of the least known genera of pelagic decapods. On the basis of collections taken during Dana Expedition 1920–22 and 1928–30, we revise the morphology of the genus. To understand the taxonomic status and position of Petalidium within other sergestid genera, we used 150 morphological characters (127 binary, 23 multistate). Three recognized species of Petalidium and eighteen type species representing all other genera of Sergestidae were included as terminals. Characters were polarized using Lucifer typus (Luciferidae: Sergestoidea) and Aristeomorpha foliacea (Aristeidae: Penaeoidea) as the outgroups. Phylogenetic analysis revealed monophyly of Petalidium comprising three species: Petalidium foliaceum Bate, 1881; Petalidium obesum (Krøyer, 1859); and Petalidium suspiriosum Burkenroad, 1937. Phylogenetic analyses also revealed possible monophyly of the clade including 15 new genera of the former Sergia and Sergestes and the position of Lucifer (family Luciferidae) within the clade Sergestidae. These results highlight necessity of future phylogenetic analyses of the remaining genera Lucifer, Acetes, Peisos, and Sicyonella involving all species of these genera and promise interesting changes for the classification of Sergestoidea. Morphological trends within Sergestoidea are discussed, and an emended diagnosis of Petalidium and diagnoses of the species it includes are given. All species are illustrated and biology of the genus is discussed. Keys to species of Petalidium based upon new information are presented. © 2015 The Linnean Society of London     

Mapping the amino acid properties of constituent nucleoporins onto the yeast nuclear pore complex

Visualization of molecular structures aids in the understanding of structural and functional roles of biological macromolecules. Macromolecular transport between the cell nucleus and cytoplasm is facilitated by the nuclear pore complex (NPC). The ring structure of the NPC is large and contains several distinct proteins (nucleoporins) which function as a selective gate for the passage of certain molecules into and out of the nucleus. In this note we demonstrate the utility of a python code that allows direct mapping of the physiochemical properties of the constituent nucleoporins on the scaffold of the yeast NPC׳s cytoplasmic view. We expect this tool to be useful for researchers to visualize the NPC based on their physiochemical properties and how it alters when specific mutations are introduced in one or more of the nucleoporins. The code developed using Python is available freely from the authors.     

Phylogeny and classification of the shrimp genera Acetes,Peisos, and Sicyonella (Sergestidae: Crustacea: Decapoda)

Despite their role in marine systems, Sergestidae remain one of the most poorly understood families amongst planktonic shrimps with regard to phylogeny. Recent morphological and phylogenetic revisions of a number of sergestid genera have disentangled classificatory problems and emphasized the importance of reproductive structures for the taxonomy and phylogeny of the Sergestidae. Only three genera, Acetes, Peisos, and Sicyonella, remain unrevised phylogenetically. We undertook a phylogenetic analysis of these groups based on 124 morphological characters (120 binary, four multistate). Eighteen new characters were based on scanning electron microscopy studies of the clasping organ and petasma. The phylogenetic analysis revealed statistically supported monophyly of the clades Sicyonella and Acetes + Peisos. We combine Peisos and Acetes into a monophyletic genus Acetes, give emended diagnoses and keys to all species of Sicyonella and Acetes, and discuss morphological trends within these genera. We present maps of geographical distribution for all valid species of Acetes. © 2015 The Linnean Society of London