Cloning and characterization of cDNAs encoding S-RNases from almond (Prunus dulcis): primary structural features  and sequence diversity of the S-RNases in Rosaceae

Echinodermata is a phylum of marine invertebrates which has been extant since Cambrian time (c.a. 500 m.y. before the present). Modern examples of echinoderms include sea urchins, sea stars, and sea lilies (crinoids). The endoskeletons of echinoderms are composed of plates or ossicles (Fig. 1) which are with few exceptions, porous, single crystals of high-magnesian calcite. Despite their single crystal nature, fracture surfaces do not exhibit the near-perfect {10.4} cleavage characteristic of inorganic calcite. This paradoxical mix of biogenic and inorganic features has prompted much recent work on echinoderm skeletal crystallography. Furthermore, fossil echinoderm hard parts comprise a volumetrically significant portion of some marine limestones sequences. The ultrastructural and microchemical characterization of modern skeletal material should lend insight into: 1). The nature of the biogenic processes involved, for example, the relationship of Mg heterogeneity to morphological and structural features in modern echinoderm material, and 2). The nature of the diagenetic changes undergone by their ancient, fossilized counterparts. In this study, high resolution TEM (HRTEM), high voltage TEM (HVTEM), and STEM microanalysis are used to characterize tha ultrastructural and microchemical composition of skeletal elements of the modern crinoid Neocrinus blakei.

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Ultrastructural identification of three types of sensory setae on copepod antennae

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100141159 ◽

1995 ◽

Vol 53 ◽

pp. 956-957

Author(s):

T. M. Weatherby ◽

P.H. Lenz

Keyword(s):

Phase Locking ◽

Membrane Surface ◽

Reaction Times ◽

High Sensitivity ◽

Structural Features ◽

Calanoid Copepods ◽

Marine Food Webs ◽

Dendritic Membrane ◽

Ultrastructural Characterization

Crustaceans, as well as other arthropods, are covered with sensory setae and hairs, including mechanoand chemosensory sensillae with a ciliary origin. Calanoid copepods are small planktonic crustaceans forming a major link in marine food webs. In conjunction with behavioral and physiological studies of the antennae of calanoids, we undertook the ultrastructural characterization of sensory setae on the antennae of Pleuromamma xiphias.Distal mechanoreceptive setae exhibit exceptional behavioral and physiological performance characteristics: high sensitivity (<10 nm displacements), fast reaction times (<1 msec latency) and phase locking to high frequencies (1-2 kHz). Unusual structural features of the mechanoreceptors are likely to be related to their physiological sensitivity. These features include a large number (up to 3000) of microtubules in each sensory cell dendrite, arising from or anchored to electron dense rods associated with the ciliary basal body microtubule doublets. The microtubules are arranged in a regular array, with bridges between and within rows. These bundles of microtubules extend far into each mechanoreceptive seta and terminate in a staggered fashion along the dendritic membrane, contacting a large membrane surface area and providing a large potential site of mechanotransduction.

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Quantitative nano-characterization of heterogeneous catalysts

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100138361 ◽

1995 ◽

Vol 53 ◽

pp. 398-399

Author(s):

P.A. Crozier ◽

M. Pan

Keyword(s):

Heterogeneous Catalysts ◽

Low Dose ◽

Imaging Techniques ◽

Structural Features ◽

Catalyst Characterization ◽

New Developments ◽

Double Phase ◽

Phase Systems ◽

Dose Imaging

Heterogeneous catalysts can be of varying complexity ranging from single or double phase systems to complicated mixtures of metals and oxides with additives to help promote chemical reactions, extend the life of the catalysts, prevent poisoning etc. Although catalysis occurs on the surface of most systems, detailed descriptions of the microstructure and chemistry of catalysts can be helpful for developing an understanding of the mechanism by which a catalyst facilitates a reaction. Recent years have seen continued development and improvement of various TEM, STEM and AEM techniques for yielding information on the structure and chemistry of catalysts on the nanometer scale. Here we review some quantitative approaches to catalyst characterization that have resulted from new developments in instrumentation.HREM has been used to examine structural features of catalysts often by employing profile imaging techniques to study atomic details on the surface. Digital recording techniques employing slow-scan CCD cameras have facilitated the use of low-dose imaging in zeolite structure analysis and electron crystallography. Fig. la shows a low-dose image from SSZ-33 zeolite revealing the presence of a stacking fault.

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kangaroo, a Mobile Element From Volvox carteri, Is a Member of a Newly Recognized Third Class of Retrotransposons

Genetics ◽

10.1093/genetics/162.4.1617 ◽

2002 ◽

Vol 162 (4) ◽

pp. 1617-1630

Author(s):

Leonard Duncan ◽

Kristine Bouckaert ◽

Fay Yeh ◽

David L Kirk

Keyword(s):

Genomic Structure ◽

Mobile Element ◽

Direct Repeat ◽

Structural Features ◽

Volvox Carteri ◽

Developmentally Regulated ◽

Closed Circle ◽

Integration Mechanisms ◽

And Function

Abstract Retrotransposons play an important role in the evolution of genomic structure and function. Here we report on the characterization of a novel retrotransposon called kangaroo from the multicellular green alga, Volvox carteri. kangaroo elements are highly mobile and their expression is developmentally regulated. They probably integrate via double-stranded, closed-circle DNA intermediates through the action of an encoded recombinase related to the λ-site-specific integrase. Phylogenetic analysis indicates that kangaroo elements are closely related to other unorthodox retrotransposons including PAT (from a nematode), DIRS-1 (from Dictyostelium), and DrDIRS1 (from zebrafish). PAT and kangaroo both contain split direct repeat (SDR) termini, and here we show that DIRS-1 and DrDIRS1 elements contain terminal features structurally related to SDRs. Thus, these mobile elements appear to define a third class of retrotransposons (the DIRS1 group) that are unified by common structural features, genes, and integration mechanisms, all of which differ from those of LTR and conventional non-LTR retrotransposons.

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Characterization of putative salinity-responsive biomarkers in olive (Olea europaea L.)

Plant Genetic Resources ◽

10.1017/s1479262121000174 ◽

2021 ◽

pp. 1-11

Author(s):

Monther T. Sadder ◽

Ahmad F. Ateyyeh ◽

Hodayfah Alswalmah ◽

Adel M. Zakri ◽

Abdullah A. Alsadon ◽

...

Keyword(s):

Food Production ◽

Stress Protein ◽

Adaptor Protein ◽

Structural Features ◽

Nacl Stress ◽

Soil Salinization ◽

Limiting Factors ◽

Stress Levels ◽

Quality Water

Abstract Low-quality water and soil salinization are increasingly becoming limiting factors for food production, including olive – a major fruit crop in several parts of the world. Identifying putative salinity-stress tolerance in olive would be helpful in the future development of new tolerant varieties. In this study, novel salinity-responsive biomarkers (SRBs) were characterized in the species, namely, monooxygenase 1 (OeMO1), cation calcium exchanger 1 (OeCCX1), salt tolerance protein (OeSTO), proteolipid membrane potential modulator (OePMP3), universal stress protein (OeUSP2), adaptor protein complex 4 medium mu4 subunit (OeAP-4), WRKY1 transcription factor (OeWRKY1) and potassium transporter 2 (OeKT2). Unique structural features were highlighted for encoded proteins as compared with other plant homologues. The expression of olive SRBs was investigated in leaves of young plantlets of two cultivars, ‘Nabali’ (moderately tolerant) and ‘Picual’ (tolerant). At 60 mM NaCl stress level, OeMO1, OeSTO, OePMP3, OeUSP2, OeAP-4 and OeWRKY1 were up-regulated in ‘Nabali’ as compared with ‘Picual’. On the other hand, OeCCX1 and OeKT2 were up-regulated at three stress levels (30, 60 and 90 mM NaCl) in ‘Picual’ as compared to ‘Nabali’. Salinity tolerance in olive presumably engages multiple sets of responsive genes triggered by different stress levels.

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Synthesis and Characterization of a Fullerenol Derivative for Potential Biological Applications

Materials Proceedings ◽

10.3390/iocn2020-07793 ◽

2020 ◽

Vol 4 (1) ◽

pp. 15

Author(s):

Eduardo Ravelo-Nieto ◽

Alvaro Duarte-Ruiz ◽

Luis H. Reyes ◽

Juan C. Cruz

Keyword(s):

Phase Transfer ◽

Protein A ◽

Structural Features ◽

Cellular Level ◽

Cellulose Membrane ◽

Cell Penetration ◽

Covalent Functionalization ◽

Dialysis Tubing ◽

Surface Functionality

Several biological barriers are generally responsible for the limited delivery of cargoes at the cellular level. Fullerenols have unique structural features and possess suitable properties for interaction with the cells. This study aimed to synthesize and characterize a fullerenol derivative with desirable characteristics (size, charge, functionality) to develop cell penetration vehicles. Fullerenol was synthesized from fullerene (C60) solubilized in toluene, followed by hydroxylation with hydrogen peroxide and tetra-n-butylammonium hydroxide (TBAH) as a phase transfer catalyst. The obtained product was purified by a Florisil chromatography column (water as the eluent), followed by dialysis (cellulose membrane dialysis tubing) and freeze-drying (yield 66%). Subsequently, a silane coupling agent was conjugated on the fullerenol surface to render free amine functional groups for further covalent functionalization with other molecules. Characterization via UV–VIS, FTIR-ATR, Raman, DLS, and SEM techniques was conducted to evaluate the composition, size, morphology, surface functionality, and structural properties. We are currently working on the conjugation of the potent cell-penetrating agents Buforin II (BUFII) and the Outer Membrane Protein A (OmpA) on the surface of the fullerenol to estimate whether cell penetration and endosome escape are improved concerning conventional polymeric vehicles and our previous developments with iron oxide nanoparticles.

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High-resolution characterization of the structural features and genetic variation of six feline leukocyte antigen class I loci via single molecule, real-time (SMRT) sequencing

Immunogenetics ◽

10.1007/s00251-021-01221-w ◽

2021 ◽

Author(s):

Jennifer C. Holmes ◽

Elizabeth H. Scholl ◽

Allison N. Dickey ◽

Paul R. Hess

Keyword(s):

Genetic Variation ◽

High Resolution ◽

Real Time ◽

Single Molecule ◽

Structural Features ◽

Class I ◽

Smrt Sequencing ◽

Leukocyte Antigen ◽

Leukocyte Antigen Class I

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Molecular Characterization of Ciliate Diversity in Stream Biofilms

Applied and Environmental Microbiology ◽

10.1128/aem.01438-07 ◽

2008 ◽

Vol 74 (6) ◽

pp. 1740-1747 ◽

Cited By ~ 52

Author(s):

Andrew Dopheide ◽

Gavin Lear ◽

Rebecca Stott ◽

Gillian Lewis

Keyword(s):

18S Rrna ◽

Pcr Primers ◽

18S Rrna Gene ◽

Sequence Diversity ◽

Rrna Genes ◽

Rrna Gene ◽

Sequencing Analysis ◽

Specific Pcr ◽

Stream Biofilms

ABSTRACT Free-living protozoa are thought to be of fundamental importance in aquatic ecosystems, but there is limited understanding of their diversity and ecological role, particularly in surface-associated communities such as biofilms. Existing eukaryote-specific PCR primers were used to survey 18S rRNA gene sequence diversity in stream biofilms but poorly revealed protozoan diversity, demonstrating a need for protozoan-targeted primers. Group-specific PCR primers targeting 18S rRNA genes of the protozoan phylum Ciliophora were therefore designed and tested using DNA extracted from cultured protozoan isolates. The two most reliable primer combinations were applied to stream biofilm DNA, followed by cloning and sequencing analysis. Of 44 clones derived from primer set 384F/1147R, 86% were of probable ciliate origin, as were 25% of 44 clones detected by primer set 121F/1147R. A further 29% of 121F/1147R-detected clones matched sequences from the closely related phylum Apicomplexa. The highly ciliate-specific primer set 384F/1147R was subsequently used in PCRs on biofilm DNA from four streams exhibiting different levels of human impact, revealing differences in ciliate sequence diversity in samples from each site. Of a total of 240 clones, 73% were of probable ciliate origin; 54 different putative ciliate sequences were detected from throughout seven taxonomic ciliate classes. Sequences from Oligohymenophorea were most commonly detected in all samples, followed by either Spirotrichea or Phyllopharyngea. Restriction fragment length polymorphism profile-based analysis of clones suggested a potentially higher level of diversity than did sequencing. Nevertheless, newly designed PCR primers 384F/1147R were considered to provide an effective molecular basis for characterization of ciliate diversity in stream biofilms.

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Preparation and Characterization of Cationized Cellulose for the Removal of Anionic Dyes

Adsorption Science & Technology ◽

10.1260/0263617011494088 ◽

2001 ◽

Vol 19 (3) ◽

pp. 197-210 ◽

Cited By ~ 32

Author(s):

A. Hashem ◽

Reda M. El-Shishtawy

Keyword(s):

Adsorption Capacity ◽

Freundlich Isotherm ◽

Structural Features ◽

Isotherm Models ◽

Acid Orange 7 ◽

Anionic Dyes ◽

Adsorption Parameters ◽

Direct Blue ◽

Equilibrium Data

The factors influencing the cationization of microcrystalline cellulose with 3-chloro-2-hydroxypropyl triethylammonium chloride in the presence of NaOH were investigated. The course of the reaction was followed by estimating the nitrogen content of the cationized product while its structural features were confirmed by IR analysis. The ability of cationized cellulose to adsorb anionic dyes, viz. Acid Orange 7, Direct Blue 75 and Direct Violet 31, was investigated at 25°C and 50°C. The equilibrium data obtained were fitted by the Langmuir and Freundlich isotherm models, allowing the corresponding adsorption parameters to be determined. The results showed that the adsorption capacity was dependent on the adsorbent, temperature, the nature of the dye and (to some extent) on van der Waals and hydrogen bonding. Cationized cellulose exhibited a much better adsorption capacity towards anionic dyes than cellulose.

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