Effect of 2-(dimethylamino) Ethyl Methacrylate on Nanostructure and Properties of pH and Temperature Sensitive Cellulose-Based Hydrogels

2020 ◽  
Vol 20 (3) ◽  
pp. 1799-1806
Author(s):  
Ping Jiang ◽  
Shaowei Chen ◽  
Linda Lv ◽  
Hongmin Ji ◽  
Gen Li ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Temperature Response ◽  
Light Transmittance ◽  
Dimensional Structure ◽  
Temperature Sensitive ◽  
The Novel ◽  
Ethyl Methacrylate ◽  
3D Network ◽  
Swelling Rate ◽  
Equilibrium Swelling Ratio

The novel double responsive cellulose/poly 2-(dimethylamino) ethyl methacrylate (PDMAEMA) hydrogel was synthesized via in situ free radical polymerization. The results from light transmittance measurements, scanning electron microscopy (SEM), mechanical property testing as well as swelling experiments demonstrated that DMAEMA played a significant impact on in hydrogel’s nanostructure.With increasing DMAEMA concentration, the transparency of hydrogels dropped and texture became softer. The incorporation of relatively hard cellulose and increase in crosslink density significantly enhanced 3D network structure of hydrogel. The tensile strength, compression and bending capabilities of the composite responsive hydrogels were fine with the DMAEMA in a certain range. When the DMAEMA concentration increased to 6 g/g(cellulose), the mechanical strength decreased noticeably. An increase in DMAEMA concentration resulted in a faster initial swelling rate and higher equilibrium swelling ratio. Further, three-dimensional structure and increase of DMAEMA concentration can also improve pH and temperature response sensitivity of hydrogels. Thus, the mechanical, swelling and responsive properties of hydrogel could be adjusted by the DMAEMA and polymerization modes.

scholarly journals Mutual Correction of Faulty PCNA Subunits in Temperature-Sensitive Lethal mus209 Mutants of Drosophila melanogaster

Genetics ◽  
2000 ◽  
Vol 154 (4) ◽  
pp. 1721-1733
Author(s):  
Daryl S Henderson ◽  
Ulrich K Wiegand ◽  
David G Norman ◽  
David M Glover
Keyword(s):  
Germ Line ◽  
Position Effect ◽  
Three Dimensional ◽  
Nuclear Antigen ◽  
Dimensional Structure ◽  
Female Sterility ◽  
Temperature Sensitive ◽  
Position Effect Variegation ◽  
Dna Double Strand Breaks ◽  
Mutant Genotype

Abstract Proliferating cell nuclear antigen (PCNA) functions in DNA replication as a processivity factor for polymerases δ and ε, and in multiple DNA repair processes. We describe two temperature-sensitive lethal alleles (mus209B1 and mus2092735) of the Drosophila PCNA gene that, at temperatures permissive for growth, result in hypersensitivity to DNA-damaging agents, suppression of position-effect variegation, and female sterility in which ovaries are underdeveloped and do not produce eggs. We show by mosaic analysis that the sterility of mus209B1 is partly due to a failure of germ-line cells to proliferate. Strikingly, mus209B1 and mus2092735 interact to restore partial fertility to heteroallelic females, revealing additional roles for PCNA in ovarian development, meiotic recombination, and embryogenesis. We further show that, although mus209B1 and mus2092735 homozygotes are each defective in repair of transposase-induced DNA double-strand breaks in somatic cells, this defect is substantially reversed in the heteroallelic mutant genotype. These novel mutations map to adjacent sites on the three-dimensional structure of PCNA, which was unexpected in the context of this observed interallelic complementation. These mutations, as well as four others we describe, reveal new relationships between the structure and function of PCNA.

scholarly journals Hydrothermal Synthesis and Structural Investigation of a Crystalline Uranyl Borosilicate

Inorganics ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 25
Author(s):  
Kristen A. Pace ◽  
Vladislav V. Klepov ◽  
Mark D. Smith ◽  
Travis Williams ◽  
Gregory Morrison ◽  
...  
Keyword(s):  
Synthesis Method ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Exploratory Research ◽  
The Novel ◽  
Orthorhombic Space Group ◽  
Crystalline Materials ◽  
Waste Remediation ◽  
And Storage ◽  
X Ray Absorption

The relevance of multidimensional and porous crystalline materials to nuclear waste remediation and storage applications has motivated exploratory research focused on materials discovery of compounds, such as actinide mixed-oxoanion phases, which exhibit rich structural chemistry. The novel phase K1.8Na1.2[(UO2)BSi4O12] has been synthesized using hydrothermal methods, representing the first example of a uranyl borosilicate. The three-dimensional structure crystallizes in the orthorhombic space group Cmce with lattice parameters a = 15.5471(19) Å, b = 14.3403(17) Å, c = 11.7315(15) Å, and V = 2615.5(6) Å3, and is composed of UO6 octahedra linked by [BSi4O12]5− chains to form a [(UO2)BSi4O12]3− framework. The synthesis method, structure, results of Raman, IR, and X-ray absorption spectroscopy, and thermal stability are discussed.

scholarly journals Nanofiber-Mâché Hollow Ball Mimicking the Three-Dimensional Structure of a Cyst

Polymers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 2273
Author(s):  
Wan-Ying Huang ◽  
Norichika Hashimoto ◽  
Ryuhei Kitai ◽  
Shin-ichiro Suye ◽  
Satoshi Fujita
Keyword(s):  
Three Dimensional ◽  
Hollow Structure ◽  
Dimensional Structure ◽  
The Novel ◽  
Fibrous Scaffold ◽  
Hydrogel Beads ◽  
Inner Surface ◽  
Intracranial Epidermoid ◽  
Hollow Ball

The occasional malignant transformation of intracranial epidermoid cysts into squamous cell carcinomas remains poorly understood; the development of an in vitro cyst model is urgently needed. For this purpose, we designed a hollow nanofiber sphere, the “nanofiber-mâché ball.” This hollow structure was fabricated by electrospinning nanofiber onto alginate hydrogel beads followed by dissolving the beads. A ball with approximately 230 mm3 inner volume provided a fibrous geometry mimicking the topography of the extracellular matrix. Two ducts located on opposite sides provided a route to exchange nutrients and waste. This resulted in a concentration gradient that induced oriented migration, in which seeded cells adhered randomly to the inner surface, formed a highly oriented structure, and then secreted a dense web of collagen fibrils. Circumferentially aligned fibers on the internal interface between the duct and hollow ball inhibited cells from migrating out of the interior, similar to a fish bottle trap. This structure helped to form an adepithelial layer on the inner surface. The novel nanofiber-mâché technique, using a millimeter-sized hollow fibrous scaffold, is excellently suited to investigating cyst physiology.

scholarly journals Identification, Characterization, and Three-Dimensional Structure of the Novel Circular Bacteriocin, Enterocin NKR-5-3B, fromEnterococcus faecium

Biochemistry ◽  
2015 ◽  
Vol 54 (31) ◽  
pp. 4863-4876 ◽  
Author(s):  
Kohei Himeno ◽  
K. Johan Rosengren ◽  
Tomoko Inoue ◽  
Rodney H. Perez ◽  
Michelle L. Colgrave ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Dimensional Structure ◽  
The Novel ◽  
Three Dimensional Structure ◽  
Circular Bacteriocin

Role of LHCII-containing macrodomains in the structure, function and dynamics of grana

2000 ◽  
Vol 27 (3) ◽  
pp. 279 ◽  
Author(s):  
G. Garab ◽  
L. Mustárdy
Keyword(s):  
Excitation Energy ◽  
Long Range ◽  
Structural Changes ◽  
Higher Plants ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Lateral Heterogeneity ◽  
Long Distance ◽  
3D Network

In higher plants and green algae two types of thylakoids are distinguished, granum (stacked) and stroma (unstacked) thylakoids. They form a three-dimensional (3D) network with large lateral heterogeneity: photosystem II (PSII) and the associated main chlorophyll a/b light-harvesting complex (LHCII) are found predominantly in the stacked region, while PSI and LHCI are located mainly in the unstacked region of the membrane. This picture emerged from the discovery of the physical separation of the two photosystems (Boardman and Anderson 1964). Granal chloroplasts possess significant flexibility, which is essential for optimizing the photosynthetic machinery under various environmental conditions. However, our understanding concerning the assembly, structural dynamics and regulatory functions of grana is far from being complete. In this paper we overview the significance of the three-dimensional structure of grana in the absorption properties, ionic equilibrations, and in the diffusion of membrane components between the stacked and unstacked regions. Further, we discuss the role of chiral macrodomains in the grana. Lateral heterogeneity of thylakoid membranes is proposed to be a consequence of the formation of macrodomains constituted of LHCII and PSII; their long range order permits long distance migration of excitation energy, which explains the energetic connectivity of PSII particles. The ability of macrodomains to undergo light-induced reversible structural changes lends structural flexibility to the granum. In purified LHCII, which has also been shown to form stacked lamellar aggregates with long range chiral order, excitation energy migrates for large distances; these macroaggregates are also capable of undergoing light-induced reversible structural changes and fluorescence quenching. Hence, some basic properties of grana appear to originate from its main constituent, the LHCII.

scholarly journals Identification of a positive regulator of the cell cycle ubiquitin-conjugating enzyme Cdc34 (Ubc3).

1996 ◽  
Vol 16 (2) ◽  
pp. 677-684 ◽  
Author(s):  
J A Prendergast ◽  
C Ptak ◽  
D Kornitzer ◽  
C N Steussy ◽  
R Hodgins ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Amino Acid ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Temperature Sensitive ◽  
Reading Frame ◽  
Positive Regulator ◽  
Morphological Defects ◽  
Ubiquitin Conjugating Enzyme ◽  
Conjugating Enzyme

The Cdc34 (Ubc3) ubiquitin-conjugating enzyme from Saccharomyces cerevisiae plays an essential role in the progression of cells from the G1 to S phase of the cell division cycle. Using a high-copy suppression strategy, we have identified a yeast gene (UBS1) whose elevated expression suppresses the conditional cell cycle defects associated with cdc34 mutations. The UBS1 gene encodes a 32.2-kDa protein of previously unknown function and is identical in sequence to a genomic open reading frame on chromosome II (GenBank accession number Z36034). Several lines of evidence described here indicate that Ubs1 functions as a general positive regulator of Cdc34 activity. First, overexpression of UBS1 suppresses not only the cell proliferation and morphological defects associated with cdc34 mutants but also the inability of cdc34 mutant cells to degrade the general amino acid biosynthesis transcriptional regulator, Gcn4. Second, deletion of the UBS1 gene profoundly accentuates the cell cycle defect when placed in combination with a cdc34 temperature-sensitive allele. Finally, a comparison of the Ubs1 and Cdc34 polypeptide sequences reveals two noncontiguous regions of similarity, which, when projected onto the three-dimensional structure of a ubiquitin-conjugating enzyme, define a single region situated on its surface. While cdc34 mutations corresponding to substitutions outside this region are suppressed by UBS1 overexpression, Ubs1 fails to suppress amino acid substitutions made within this region. Taken together with other findings, the allele specificity exhibited by UBS1 expression suggests that Ubs1 regulates Cdc34 by interaction or modification.

scholarly journals Efficacy of Novel Hemagglutinin-Neuraminidase Inhibitors BCX 2798 and BCX 2855 against Human Parainfluenza Viruses In Vitro and In Vivo

2004 ◽  
Vol 48 (5) ◽  
pp. 1495-1502 ◽  
Author(s):  
Irina V. Alymova ◽  
Garry Taylor ◽  
Toru Takimoto ◽  
Tsu-Hsing Lin ◽  
Pooran Chand ◽  
...  
Keyword(s):  
Sendai Virus ◽  
Three Dimensional ◽  
Parainfluenza Virus ◽  
Dimensional Structure ◽  
The Novel ◽  
Virus Infections ◽  
Parainfluenza Viruses ◽  
Human Parainfluenza Viruses

ABSTRACT Human parainfluenza viruses are important respiratory tract pathogens, especially of children. However, no vaccines or specific therapies for infections caused by these viruses are currently available. In the present study we characterized the efficacy of the novel parainfluenza virus inhibitors BCX 2798 and BCX 2855, which were designed based on the three-dimensional structure of the hemagglutinin-neuraminidase (HN) protein. The compounds were highly effective in inhibiting hemagglutinin (HA) and neuraminidase (NA) activities and the growth of hPIV-1, hPIV-2, and hPIV-3 in LLC-MK2 cells. The concentrations required to reduce the activity to 50% of that of a control ranged from 0.1 to 6.0 μM in HA inhibition assays and from 0.02 to 20 μM in NA inhibition assays. The concentrations required to inhibit virus replication to 50% of the level of the control ranged from 0.7 to 11.5 μM. BCX 2798 and BCX 2855 were inactive against influenza virus HA and NA and bacterial NA. In mice infected with a recombinant Sendai virus whose HN gene was replaced with that of hPIV-1 [rSV(hHN)], intranasal administration of BCX 2798 (10 mg/kg per day) and of BCX 2855 (50 mg/kg per day) 4 h before the start of infection resulted in a significant reduction in titers of virus in the lungs and protection from death. Treatment beginning 24 h after the start of infection did not prevent death. Together, our results indicate that BCX 2798 and BCX 2855 are effective inhibitors of parainfluenza virus HN and may limit parainfluenza virus infections in humans.

scholarly journals Structure–Function Relationships in Yeast Tubulins

2000 ◽  
Vol 11 (5) ◽  
pp. 1887-1903 ◽  
Author(s):  
Kristy L. Richards ◽  
Kirk R. Anders ◽  
Eva Nogales ◽  
Katja Schwartz ◽  
Kenneth H. Downing ◽  
...  
Keyword(s):  
Synthetic Lethality ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Cold Sensitivity ◽  
Temperature Sensitive ◽  
Large Patch ◽  
Tubulin Dimer ◽  
The Core ◽  
Synthetically Lethal ◽  
Β Tubulin

A comprehensive set of clustered charged-to-alanine mutations was generated that systematically alter TUB1, the major α-tubulin gene of Saccharomyces cerevisiae. A variety of phenotypes were observed, including supersensitivity and resistance to the microtubule-destabilizing drug benomyl, lethality, and cold- and temperature-sensitive lethality. Many of the most benomyl-sensitivetub1 alleles were synthetically lethal in combination with tub3Δ, supporting the idea that benomyl supersensitivity is a rough measure of microtubule instability and/or insufficiency in the amount of α-tubulin. The systematictub1 mutations were placed, along with the comparable set of tub2 mutations previously described, onto a model of the yeast α–β-tubulin dimer based on the three-dimensional structure of bovine tubulin. The modeling revealed a potential site for binding of benomyl in the core of β-tubulin. Residues whose mutation causes cold sensitivity were concentrated at the lateral and longitudinal interfaces between adjacent subunits. Residues that affect binding of the microtubule-binding protein Bim1p form a large patch across the exterior-facing surface of α-tubulin in the model. Finally, the positions of the mutations suggest that proximity to the α–β interface may account for the finding of synthetic lethality of five viable tub1 alleles with the benomyl-resistant but otherwise entirely viable tub2-201allele.

Role of LHCII-containing macrodomains in the structure, function and dynamics of grana

2000 ◽  
Vol 27 (7) ◽  
pp. 723 ◽  
Author(s):  
G. Garab ◽  
L. Mustárdy
Keyword(s):  
Excitation Energy ◽  
Long Range ◽  
Structural Changes ◽  
Higher Plants ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Lateral Heterogeneity ◽  
Long Distance ◽  
3D Network

In higher plants and green algae two types of thylakoids are distinguished, granum (stacked) and stroma (unstacked) thylakoids. They form a three-dimensional (3D) network with large lateral heterogeneity: photosystem II (PSII) and the associated main chlorophyll a/b light-harvesting complex (LHCII) are found predominantly in the stacked region, while PSI and LHCI are located mainly in the unstacked region of the membrane. This picture emerged from the discovery of the physical separation of the two photosystems (Boardman and Anderson 1964). Granal chloroplasts possess significant flexibility, which is essential for optimizing the photosynthetic machinery under various environmental conditions. However, our understanding concerning the assembly, structural dynamics and regulatory functions of grana is far from being complete. In this paper we overview the significance of the three-dimensional structure of grana in the absorption properties, ionic equilibrations, and in the diffusion of membrane components between the stacked and unstacked regions. Further, we discuss the role of chiral macrodomains in the grana. Lateral heterogeneity of thylakoid membranes is proposed to be a consequence of the formation of macrodomains constituted of LHCII and PSII; their long range order permits long distance migration of excitation energy, which explains the energetic connectivity of PSII particles. The ability of macrodomains to undergo light-induced reversible structural changes lends structural flexibility to the granum. In purified LHCII, which has also been shown to form stacked lamellar aggregates with long range chiral order, excitation energy migrates for large distances; these macroaggregates are also capable of undergoing light-induced reversible structural changes and fluorescence quenching. Hence, some basic properties of grana appear to originate from its main constituent, the LHCII.

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