bluuebunny/crossref_metadata_2025 huggingface dataset:
Asn141 is essential for DNA recognition by EcoRI restriction endonuclease
Authors: Fritz Andreas , Küster Wolfgang , Alves Jürgen
Published: July 2002

The amino acid residue Asn141 of the restriction endonuclease EcoRI was proposed to make three hydrogen bonds to both adenine residues within the recognition sequence ‐GAATTC‐. We have mutated Asn141 to alanine, aspartate, serine, and tyrosine. Only the serine mutant is active under normal buffer conditions although 1000‐fold less than wild‐type EcoRI. The alanine and aspartate mutants can be activated by Mn2+. At acidic pH the latter mutant becomes even more active than the wild‐type enzyme in the presence of Mn2+. We conclude that Asn141 is essential for DNA recognition and that serine can partly substitute it.
Molecular analysis of regulation of gene expression of the human erythroid anion exchanger (AE) 1
Authors: Philipp Stephan , Kneussel Matthias , König Jörg , Appelhans Heribert
Published: July 2002

The anion exchange protein AE1 is the most abundant membrane protein in human erythrocytes mediating the electroneutral chloride/bicarbonate exchange. We identified a promoter region in the 5′ flanking region of the human AE1 gene which controls transcription in a cell type independent manner. In addition a second, distal promoter element mediates gene expression only in erythroid cells and in dependence upon differentiation. Within this distal promoter region we defined a 44 bp sequence containing a novel CT‐rich motif with very strong promoter activity whereas a second 28 bp segment suppresses gene expression.
Estrogen withdrawal‐induced human breast cancer tumour regression in nude mice is prevented by Bcl‐2
Authors: Pratt M.A.Christine , Krajewski Stanislaw , Menard Michel , Krajewska Maryla , Macleod Heather , Reed John C
Published: July 2002

We recently showed that estrogen induces expression of the anti‐apoptotic protein, Bcl‐2 in MCF‐7 human breast cancer cells. Since estrogen‐dependent breast tumours can regress following estrogen withdrawal, we hypothesized that stable Bcl‐2 expression would prevent estrogen‐withdrawal induced regression of MCF‐7 tumours. We therefore established tumours in ovariectomized female nude mice implanted with an estrogen‐release pellet using untransfected MCF‐7 cells or MCF‐7 cells stably transfected with a Bcl‐2 cDNA sense or antisense expression vector. All tumours grew at similar rates indicating that Bcl‐2 levels have no effect on tumour formation. After removal of the estrogen pellet, Bcl‐2 antisense tumours and untransfected MCF‐7 tumours regressed means of 49% and 52%, respectively, after estrogen pellet removal whereas Bcl‐2 sense tumours were significantly stabilized. Regressing tumours displayed characteristics of apoptotic cells. These results show that Bcl‐2 can prevent hormone‐dependent breast tumour regression and are consistent with the notion that decreased Bcl‐2 levels following estrogen withdrawal renders hormone‐dependent breast tumour cells sensitive to apoptotic regression.
Velcro in the nuclear envelope: LBR and LAPs
Authors: Chu Angel , Rassadi Roozbeh , Stochaj Ursula
Published: July 2002

The nuclear envelope is crucial for the functional organization of the nucleus. Lamin B receptor (LBR) and several lamina‐associated proteins (LAPs), residing in the inner membrane, provide attachment sites for chromatin and the nuclear lamina. LAPs and LAP‐related proteins are members of a growing family of proteins, whose genes are expressed in a tissue and development specific manner, opening the opportunity for a complex regulation of membrane‐chromatin and membrane‐lamina interactions. Post‐translational modifications of LBR and LAPs are likely to modulate their binding to lamins and chromatin, interactions that need to be dynamic to accommodate nuclear growth in interphase and nuclear envelope disassembly in mitosis. Accumulation of proteins in the inner nuclear membrane is believed to depend on their retention mediated by the interaction with nuclear components such as chromatin and lamins.
Differentiation elicits negative regulation of human β‐galactoside α2,6‐sialyltransferase at the mRNA level in the HL‐60 cell line
Authors: Taniguchi Akiyoshi , Higai Koji , Hasegawa Yuko , Utsumi Kunio , Matsumoto Kojiro
Published: July 2002

We studied the regulation of the β‐galactoside α2,6‐sialyltransferase (hST6Gal I) gene during HL‐60 cell differentiation induced with dimethyl sulfoxide (DMSO), all trans‐retinoic acid (ATRA), and phorbol myristate acetate (PMA). During HL‐60 cell line differentiation, cell surface levels of α2,6‐sialic acids expression decreased, as measured by flow cytometric analysis using Sambucus nigra agglutinin (SNA). Activities of hST6Gal I and levels of hST6Gal I mRNA dramatically decreased after 1 day of stimulation. Using reverse transcription polymerase chain reaction (PT‐PCR), we found the major hST6Gal I mRNA isoform in HL‐60 cells contains 5′‐untranslated exons Y and Z. These results suggest that the expression of cell surface α2,6‐sialic acids is controlled at the mRNA level, which is regulated by a promoter located 5′‐upstream of exon Y.
Differential sensitivities of primary and secondary T cell responses to antigen structure
Authors: Nayak B.P
Published: July 2002

Here we examined T cell responses to two analogs of a chimeric peptide encoding a known B and a known T cell epitope. In one of the analogs, the B cell epitope existed in a random conformation whereas it was restricted within a disulfide‐bonded cyclic loop in the other. Immunization of these peptides in mice revealed that the latter peptide was significantly poorer at priming T cells and our preliminary results suggest this could be the result of differential processing of the two analogs. While primary T cell responses were sensitive to the influence of conformation, secondary responses were not discriminatory for the two antigens confirming the differences in activation requirements for primary and secondary T cell responses. Further, our studies also suggest that the priming efficacy of a T cell epitope is influenced by its structural environment.
IS3 peptide‐formed ion channels in rat skeletal muscle cell membranes
Authors: Bao Lin , Miao Zhen-Wei , Zhou Pei-Ai , Jiang Yun , Sha Yin-Lin , Zhang Ren-Ji , Tang You-Chi
Published: July 2002

A 22‐mer peptide, identical to the primary sequence of domain I segment 3 (IS3) of rat brain sodium channel I, was synthesized. With the patch clamp cell‐attached technique, single channel currents could be recorded from the patches of cultured rat myotube membranes when the patches were held at hyperpolarized potentials and the electrode solution contained NaCl and 1 μM IS3, indicating that IS3 incorporated into the membranes and formed ion channels. The single channel conductances of IS3 channels were distributed heterogeneously, but mainly in the range of 10–25 pS. There was a tendency that the mean open time and open probability of IS3 channels increased and the mean close time decreased with the increasing of hyperpolarized membrane potentials. IS3 channels are highly selective for Na+ and Li+ but not for Cl− and K+, similar to the authentic Na+ channels.
Evidence for peroxynitrite formation during S‐nitrosoglutathione photolysis in air saturated solutions
Authors: Mutus Bulent , Redmond Robert W , Akhter Shirin
Published: July 2002

Flash photolysis of S‐nitrosoglutathione (GSNO) in aerated solutions at pH 10 gave rise to an absorption with a maximum around 310–320 nm. This peak is spectrally similar to that displayed by ONOO−. The decay kinetics of this absorption was compared to that of authentic ONOO−, generated independently. An excellent correlation was obtained. Further proof of ONOO− generation was provided by HPLC studies showing the production of 3‐nitrotyrosine on irradiation of GSNO in the presence of tyrosine at pH 7.4. In addition, the nitration yield was increased ∼5‐fold in the presence of bicarbonate and totally eliminated with DMPO, indicating the requirement of a radical intermediate for peroxynitrite production during S‐nitrosothiol photolysis.
Structure of the human CpG‐island‐containing lung Kruppel‐like factor (LKLF) gene and its location in chromosome 19p13.11–13 locus
Authors: Kozyrev Sergey V. , Hansen Lise Lotte , Poltaraus Andrew B. , Domninsky Dmitry A. , Kisselev Lev L.
Published: July 2002

We have cloned earlier a short human genomic fragment which showed strong similarity with the mouse cDNA encoding lung Kruppel‐like zinc finger transcription factor (LKLF), predominantly expressed in mouse developing lung, spleen, and vascular system, which might play a key role in programming the quiescent state of single positive T cells and blood vessel wall morphogenesis. Here we report the successful cloning of the human LKLF cDNA, its genomic structure and chromosomal localization at the 19p13.11–p13.13 locus. The full‐length human LKLF cDNA has longer 5′‐UTR with higher GC content than mouse cDNA and encodes a predicted protein of 355 amino acids which has three zinc fingers at the C‐terminus and a proline‐rich N‐terminal domain. Human and mouse proteins share 87.3% identity and 90.2% amino acid similarity. The human LKLF gene consists of three exons. From the proximal promoter to the end of the second exon, we have found a CpG island with an average 76% GC content and two regions of unusually high GC density.
The inhibitory effect of 2‐deoxyglucose on insulin receptor autophosphorylation does not depend on known serine phosphorylation sites or other conserved serine residues of the receptor β‐subunit
Authors: Strack Volker , Bossenmaier Birgit , Stoyanov Borislav , Mosthaf Luitgard , Kellerer Monika , Lammers Reiner , Häring Hans-U.
Published: July 2002

Hyperglycemia induces insulin resistance in diabetic patients. It is known that supraphysiological levels of D‐glucose or 2‐deoxyglucose inhibit the insulin receptor and it is speculated that this effect is mediated by serine phosphorylation of the insulin receptor β‐subunit and other proteins of the insulin signaling chain. To test this hypothesis we prepared point mutations of the human insulin receptor where serine was exchanged to alanine at 16 different positions, either at known phosphorylation sites or at positions which are conserved in different tyrosine kinase receptors. These receptor constructs were expressed in HEK 293 cells and the effect of 2‐deoxyglucose (25 mM) on insulin (100 nM) induced receptor autophosphorylation was studied. 2‐Deoxyglucose consistently inhibits insulin stimulated autophosphorylation of all constructs to the same degree as observed in wild‐type human insulin receptor. The data suggest that none of the chosen serine positions are involved in 2‐deoxyglucose induced receptor inhibition.
A predominantly hydrophobic recognition of H‐antigenic sugars by winged bean acidic lectin: a thermodynamic study
Authors: Srinivas V.R , Bhanuprakash Reddy G , Surolia Avadhesa
Published: July 2002

The thermodynamics of binding of winged bean (Psophocarpus tetragonolobus) acidic agglutinin to the H‐antigenic oligosaccharide (Fucα1‐2Galβ1‐4GlcNAc‐oMe) and its deoxy and methoxy congeners were determined by isothermal titration calorimetry. We report a relatively hydrophobically driven binding of winged bean acidic agglutinin to the congeners of the above sugar. This conclusion is arrived, from the binding parameters of the fucosyl congeners, the nature of the enthalpy‐entropy compensation plots and the temperature dependence of binding enthalpies of some of the congeners. Thus, the binding site of winged bean acidic agglutinin must be quite extended to accommodate the trisaccharide, with non‐polar loci that recognize the fucosyl moiety of the H‐antigenic determinant.
Characterization of a novel cis‐benzene dihydrodiol dehydrogenase from Pseudomonas putida ML2
Authors: Fong Karen P.Y , Tan Hai-Meng
Published: July 2002

A second and novel cis‐benzene dihydrodiol dehydrogenase which is able to dehydrogenate a range of cis‐dihydrodiols and other vicinal alcohols has been purified from Pseudomonas putida ML2. The enzyme is a tetramer of a polypeptide of 39 kDa in molecular mass and has a pH optimum of 9.0. Despite having a primary structure that has significant similarity to glycerol dehydrogenases, the k
cat/K
m value of the enzyme for cis‐benzene dihydrodiol is 4300‐fold higher compared to glycerol. The apparent K
m values of the enzyme for cis‐benzene dihydrodiol and glycerol are 0.01 mM and 46 mM, respectively, and 0.22 mM for NAD+.
Two forms of N intermediate (Nopen and Nclosed) in the bacteriorhodopsin photocycle
Authors: Radionov Alexey N , Kaulen Andrey D
Published: July 2002

Glutaraldehyde, aluminum ions and glycerol (that inhibit the M intermediate decay in the wild‐type bacteriorhodopsin and azide‐induced M decay in the D96N mutant by stabilization of the Mclosed) accelerate the N decay in the D96N mutant. The aluminum ions, the most potent activator of the N decay, induce a blue shift of the N difference spectrum by ∽10 nm. Protonated azide as well as acetate and formate inhibit the N decay in both the D96N mutant and the wild‐type protein. It is concluded that the N intermediate represents, in fact, an equilibrium mixture of the two (‘open’ and ‘closed’) forms. These two forms, like Mclosed and Mopen, come to an equilibrium in the microseconds range. The absorption spectrum of the Nopen is slightly shifted to red in comparison to that of the Nclosed. Again, this resembles the M forms. 13‐cis‐all‐trans re‐isomerization is assumed to occur in the Nclosed form only. Binding of 1–2 molecules of protonated azide stabilizes the Nopen form. Existence of the ‘open’ and ‘closed’ forms of the M and N intermediates provides the appropriate explanation of the cooperative phenomenon as well as some other effects on the bacteriorhodopsin photocycle. Summarizing the available data, we suggest that Mopen is identical to the MN form, whereas M1 and M2 are different substates of Mclosed.
Inhibition of amylase secretion from differentiated AR4‐2J pancreatic acinar cells by an actin cytoskeleton controlled protein tyrosine phosphatase activity
Authors: Feick Peter , Gilhaus Sven , Blum Robert , Hofmann Fred , Just Ingo , Schulz Irene
Published: July 2002

Disruption of the actin cytoskeleton in AR4‐2J pancreatic acinar cells led to an increase in cytosolic protein tyrosine phosphatase activity, abolished bombesin‐induced tyrosine phosphorylation and reduced bombesin‐induced amylase secretion by about 45%. Furthermore, both tyrosine phosphorylation and amylase secretion induced by phorbol ester‐induced activation of protein kinase C were abolished. An increase in the cytosolic free Ca2+ concentration by the Ca2+ ionophore A23187 had no effect on tyrosine phosphorylation but induced amylase release. Only when added together with phorbol ester, the same level of amylase secretion as with bombesin was reached. This amylase secretion was inhibited by about 40% by actin cytoskeleton disruption similar to that induced by bombesin. We conclude that actin cytoskeleton‐controlled protein tyrosine phosphatase activity downstream of protein kinase C activity regulates tyrosine phosphorylation which in part is involved in bombesin‐stimulated amylase secretion.
Chromatin structural transitions in Drosophila embryo cell‐free extract result in a high conformational flexibility of nucleosomal DNA
Authors: Krajewski Wladyslaw A
Published: July 2002

DNA within chromatin has considerably more restricted flexibility in comparison with naked DNA. This raises the main question of how the functioning multi‐enzyme complexes overcome the nucleosomal level of DNA packaging. We studied the DNA conformational flexibility of reconstituted chromatin in a cell‐free system derived from Drosophila embryo extracts. Using this system, we have found evidence for a energy‐ independent chromatin remodelling process that efficiently destabilizes the nucleosome structure resulting in a high conformational flexibility of nucleosomal DNA. The described chromatin remodelling process may lay on the basis of defined molecular principles governing the molecular heterogeneity of chromatin structures in vivo.
Enterococcus hirae vacuolar ATPase is expressed in response to pH as well as sodium
Authors: Ikegami Miho , Kawano Miyuki , Takase Kazuma , Yamato Ichiro , Igarashi Kazuei , Kakinuma Yoshimi
Published: July 2002

The Enterococcus hirae ntp operon encodes both a vacuolar ATPase, which transports Na+ as well as Li+, and the KtrII K+ transporter. A plasmid, in which the chloramphenicol acetyltransferase gene (CAT) was placed downstream of the ntp promoter, was introduced into a mutant totally defective in Na+ extrusion. The CAT activity of this transformant was increased preferentially by addition of NaCl, but not by LiCl, in the media or by elevating the medium pH, correlating well with the increase in amounts of the ATPase subunits observed by Western blotting. The physiological significance of these responses of the ntp promoter is discussed.
Human release factor eRF1: structural organisation of the unique functional gene on chromosome 5 and of the three processed pseudogenes
Authors: Guenet Lucienne , Toutain Bertrand , Guilleret Isabelle , Chauvel Bruno , Deaven Larry L. , Longmire Jonathan L. , Le Gall Jean-Yves , David Véronique , Le Treut André
Published: July 2002

In lower and higher eukaryotes, a family of tightly related proteins designated eRF1 (for eukaryotic release factor 1) catalyses termination of protein synthesis at all three stop codons. The human genome contains four eRF1 homologous sequences localised on chromosomes 5, 6, 7 and X. We report here the cloning and the structural analysis of the human eRF1 gene family. It appears that the gene located on chromosome 5 alone is potentially functional, whereas the other three sequences resemble processed pseudogenes. This is the first description of the structural organisation of the human eRF1 gene, which has been remarkably conserved during evolution and which is essential in the translation termination process.
Redox control of hydrogenase activity in the green alga Scenedesmus obliquus by thioredoxin and other thiols
Authors: Wünschiers Röbbe , Heide Heinrich , Follmann Hartmut , Senger Horst , Schulz Rüdiger
Published: July 2002

The activity of the NiFe‐hydrogenase from the green alga Scenedesmus obliquus is inhibited by both algal thioredoxins f and I+II, and by Escherichia coli thioredoxin. The strongest inhibition was observed with homologous chloroplastic thioredoxin f (I50=21 nM) and E. coli thioredoxin (I50=83 nM). For the homologous cytoplasmic thioredoxins I+II an I50 of 667 nM was determined. Glutathione shows a similar but much less pronounced inhibitory effect whereas dithiothreitol had no effect. In addition to glucose‐6‐phosphate dehydrogenase, NiFe‐hydrogenase is only the second enzyme known to be inhibited by reduced thioredoxin.
Molecular dynamics simulation of a synthetic four‐α‐helix bundle that binds the anesthetic halothane
Authors: Davies Lowri A. , Klein Michael L. , Scharf Daphna
Published: July 2002

The structural features of binding sites for volatile anesthetics are examined by performing a molecular dynamics simulation study of the synthetic four‐α‐helix bundles (Aα2)2, which are formed by association of two 62‐residue di‐α‐helical peptides. The peptide bundle (Aα2)2 was designed by Johansson et al. [Biochemistry 37 (1998) 1421–1429] and was shown experimentally to have a high affinity for the binding of the anesthetic halothane (CF3CBrClH) in a hydrophobic cavity. Since (Aα2)2 can exhibit either the anti or syn topologies, the two distinct bundles are simulated both in the presence and in the absence of halothane. Nanosecond length molecular dynamics trajectories were generated for each system at room temperature (T=298 K). The structural and dynamic effects of the inclusion of halothane are compared, illustrating that the structures are stable over the course of the simulation; that the (Aα2)2 bundles have suitable pockets that can accommodate halothane; that the halothane remains in the designed hydrophobic cavity in close proximity to the Trp residues with a preferred orientation; and that the dimensions of the peptide are perturbed by the inclusion of an anesthetic molecule.
Identification of a splice variant mRNA of p40phox, an NADPH oxidase component of phagocytes1
Authors: Hasebe Takeshi , Someya Akimasa , Nagaoka Isao
Published: July 2002

Northern blot analysis using p40phox cDNA probe revealed that two sizes of p40phox mRNAs were expressed in human promyelocytic HL‐60 and bone marrow cells. To characterize these mRNAs, we performed reverse transcription using total RNA from HL‐60 cells, and amplified the coding region of p40phox by polymerase chain reaction with oligonucleotide primers. Two cDNA fragments with different sizes were isolated. One was identical to a known p40phox cDNA (1054 bp) which encoded a protein of 339 residues (39 031 Da) with a calculated pI of 6.5. The other cDNA (1299 bp) contained an additional 245 bp intron 8 sequence in the open reading frame and encoded a protein of 348 residues (39 000 Da) with a calculated pI of 9.3. N‐terminal 253 residues were identical between p40phox and the variant protein, whereas C‐terminal 254–348 residues of the variant protein shared low homology with p40phox. Interestingly, the variant protein lacked PC (Phox and Cdc24p) motif of p40phox, which is assumed to be important for the interaction with p67phox. In addition, Western blot analysis revealed that the variant protein was not detected in HL‐60 cells and neutrophils. Together, these observations suggest that alternatively spliced variant mRNA of p40phox is expressed, but its protein is hardly present in myeloid cells.
Amylin evokes phosphorylation of P20 in rat skeletal muscle
Authors: Wang Yu , Xu Aimin , Cooper Garth J.S
Published: July 2002

To investigate the signal transduction events underlying amylin's actions, the amylin‐evoked protein phosphorylation cascade was analysed using two‐dimensional gel electrophoresis. We found that phosphorylation of three isoelectric variants of P20 (termed ARPP1, ARPP2 and ARPP3) was associated with amylin's actions in rat skeletal muscle. Amylin decreased phosphorylation of ARPP1 and increased phosphorylation of ARPP2 and ARPP3 in a dose‐dependent manner. Insulin inhibited amylin‐evoked phosphorylation of ARPP2 and ARPP3. The amylin‐selective antagonist rat amylin‐(8–37) completely reversed amylin's action on ARPP3 and partially decreased phosphorylation of ARPP2. By contrast, the CGRP‐selective antagonist, human CGRP‐(8–37) blocked phosphorylation of ARPP2 but had little effect on ARPP3. These results suggest that amylin modifies phosphorylation of P20 via two independent mechanisms, and that P20 might be a molecule mediating amylin's biological functions.
Transmembrane remote conformational suppression of the Gly‐332 mutation of the Tn10‐encoded metal‐tetracycline/H+ antiporter
Authors: Kawabe Tetsuhiro , Yamaguchi Akihito
Published: July 2002

Gly‐332 is a conformationally important residue of the Tn10‐encoded metal‐tetracycline/H+ antiporter (TetA(B)), which was found by random mutagenesis and confirmed by site‐directed mutagenesis. A bulky side chain at position 332 is deleterious to the transport function. A spontaneous second‐site suppressor revertant was isolated from G332S mutant and identified as the Ala‐354→Asp mutant. Gly‐332 and Ala‐354 are located on opposite ends of transmembrane segment XI. As judged from [14C]NEM binding to Cys mutants, the residue at position 354, which is originally exposed to water, was buried in the membrane by a G332S mutation through a remote conformational change of transmembrane segment XI. This effect is the same as that of a G62L mutation at position 30 through transmembrane segment II [Kimura, T., Sawai, T. and Yamaguchi, A. (1997) Biochemistry 36, 6941–6946]. Interestingly, the G332S mutation was also suppressed by the L30S mutation, and the G62L mutation was moderately suppressed by the A354D mutation. These results indicate the presence of a close conformational relationship between the flanking regions of the transmembrane segments II and XI.
Membrane interaction of TNF is not sufficient to trigger increase in membrane conductance in mammalian cells
Authors: van der Goot F.Gisou , Pugin Jérôme , Hribar Marusa , Fransen Lucie , Dunant Yves , De Baetselier Patrick , Bloc Alain , Lucas Rudolf
Published: July 2002

Tumor necrosis factor (TNF) can trigger increases in membrane conductance of mammalian cells in a receptor‐independent manner via its lectin‐like domain. A lectin‐deficient TNF mutant, lacking this activity, was able to bind to artificial liposomes in a pH‐dependent manner, but not to insert into the bilayer, just like wild type TNF. A peptide mimicking the lectin‐like domain, which can still trigger increases in membrane currents in cells, failed to interact with liposomes. Thus, the capacity of TNF to trigger increases in membrane conductance in mammalian cells does not correlate with its ability to interact with membranes, suggesting that the cytokine does not form channels itself, but rather interacts with endogenous ion channels or with plasma membrane proteins that are coupled to ion channels.
Vitronectin and its fragments purified as serum inhibitors of Staphylococcus aureus γ‐hemolysin and leukocidin, and their specific binding to the Hlg2 and the LukS components of the toxins
Authors: Katsumi Harue , Tomita Toshio , Kaneko Jun , Kamio Yoshiyuki
Published: July 2002

Staphylococcal γ‐hemolysin and leukocidin are bi‐component cytolysins, consisting of LukF (or Hlg1)/Hlg2 and LukF/LukS, respectively. Here, we purified serum inhibitors of γ‐hemolysin and leukocidin from human plasma. Protein sequencing showed that the purified inhibitors of 62, 57, 50 and 38 kDa were the vitronectin fragments with truncation(s) of the C‐terminal or both N‐ and C‐terminal regions. The purified vitronectin fragments specifically bound to the Hlg2 component of γ‐hemolysin and the LukS component of leukocidin to form high‐molecular‐weight complexes with them, leading to inhibition of the toxin‐induced lysis of human erythrocytes and human polymorphonuclear leukocytes, respectively. Intact vitronectin also showed inhibitory activity to the toxins. The ability of γ‐hemolysin and leukocidin to bind vitronectin and its fragments is a novel function of the pore‐forming cytolysins.
Normal levels of serum glycoproteins maintained in β‐1,4‐galactosyltransferase I‐knockout mice
Authors: Kido Masahiro , Asano Masahide , Iwakura Yoichiro , Ichinose Masao , Miki Kazumasa , Furukawa Kiyoshi
Published: July 2002

The galactose‐mediated clearance of serum glycoproteins from the circulation was evaluated using β‐1,4‐galactosyltransferase (β‐1,4‐GalT) I‐knockout mice. Partial structural study of the oligosaccharides released from mouse serum glycoproteins revealed that 77.4% of the oligosaccharides from β‐1,4‐GalT I+/+ mouse contain galactose, while 7.7% of those from β‐1,4‐GalT I−/− mouse were galactosylated. Under the conditions, no significant change in serum protein concentrations was observed between the normal and mutant mice. The results indicate that the hepatic asialoglycoprotein receptor‐mediated system is not functioning in the clearance of endogenous serum glycoproteins.
Mutational analysis of phosphorylation sites in the Dictyostelium myosin II tail: disruption of myosin function by a single charge change
Authors: Nock Steffen , Liang Wenchuan , Warrick Hans M , Spudich James A
Published: July 2002

The dynamic assembly/disassembly of non‐muscle myosin II filaments is critical for the regulation of enzymatic activities and localization. Phosphorylation of three threonines, 1823, 1833 and 2029, in the tail of Dictyostelium discoideum myosin II has been implicated in control of myosin filament assembly. By systematically replacing the three threonines to aspartates, mimicking a phosphorylated residue, we found that position 1823 is the most critical one for the regulation of myosin filament formation and in vivo function. Surprisingly, a single charge change is able to perturb filament formation and in vivo function of myosin II.
FLI1 mediates the selective expression of hypoxia‐inducible factor 1 target genes in endothelial cells under hypoxic conditions
Authors: Zeng Guodan , Wang Tao , Zhang Jingyao , Kang Y. James , Feng Li
Published: June 2021

The selective expression of hypoxia‐inducible factor (HIF) target genes in different physiological and pathological environments forms the basis for cellular adaptation to hypoxia in development and disease. Several E26 transformation‐specific (ETS) transcription factors have been shown to specifically regulate the expression of a subset of HIF‐2 target genes. However, it is unknown whether there are ETS factors that specifically regulate hypoxia‐induced HIF‐1 target genes. The present study was undertaken to explore whether friend leukemia integration 1 (FLI1), an ETS transcription factor, regulates the expression of HIF‐1 target genes. To investigate this possibility, EA.hy926 cells were exposed to 20% O2 (normoxia) or 1% O2 (hypoxia). Western blotting, immunofluorescence staining, and RT‐qPCR revealed that FLI1 mRNA and protein levels increased slightly and that the FLI1 protein co‐localized with HIF‐1α in the nucleus under hypoxic conditions. Further analysis showed that, in the absence of FLI1, the hypoxia‐mediated induction of HIF‐1 target genes was selectively inhibited. The results from immunoprecipitation and luciferase reporter assays indicated that FLI1 cooperates with HIF‐1α and is required for the transcriptional activation of a subset of HIF‐1 target genes with a core promoter region containing FBS in proximity to a functional hypoxia response element (HRE). Furthermore, ChIP analysis further confirmed the direct interaction between FLI1 and the promoter region of FLI1‐dependent HIF‐1 target genes under hypoxia. Together, this study demonstrates that FLI1 is involved in the transactivation of certain HIF‐1 target genes in endothelial cells under hypoxic conditions.
Reusable Energy‐Absorbing Architected Materials Harnessing Snapping‐Back Buckling of Wide Hyperelastic Columns
Authors: Chen Yuzhen , Jin Lihua
Published: June 2021

A new class of reusable energy‐absorbing architected material is developed by harnessing the snapping‐back buckling of wide hyperelastic columns. Subjected to an axial compression, a wide hyperelastic column can discontinuously buckle, snapping from one stable equilibrium state to another, leading to energy dissipation, while upon unloading, it can completely recover its undeformed state. Making use of this property, an energy‐absorbing architected material is designed by stacking layers of wide hyperelastic columns, and it is fabricated by multi‐material 3D printing and sacrificial molding. Characterized by quasi‐static and drop tests, the material shows the capability of energy dissipation and impact force mitigation in a reusable, self‐recoverable, and rate‐independent manner. A theory is established to predict the energy‐absorbing performance of the material and the influence of the column geometry and layer number. Wide tunability of the peak force, energy dissipation, and stability of the material is further demonstrated. This work provides new design strategies for developing reusable energy‐absorbing materials and opens new opportunities for improving their energy dissipation capacities.
Homogeneous Li+ Flux Distribution Enables Highly Stable and Temperature‐Tolerant Lithium Anode
Authors: Fan Chao‐Ying , Xie Dan , Zhang Xiao‐Hua , Diao Wan‐Yue , Jiang Ru , Wu Xing‐Long
Published: June 2021

3D carbon hosts can enable low‐stress Li metal anodes (LMAs) with improved structural and interfacial stability. However, the uneven Li+ flux and large concentration polarization, resulting from intrinsically poor Li affinity and limited porosity of carbon scaffolds, make the precise control of Li plating/stripping still one the key challenges facing advanced LMAs. Here it is demonstrated that a lightweight carbon scaffold, featuring parallel‐aligned porous fibers, can work well for homogeneous Li+ flux distribution and reduced concentration gradient to form a stable solid electrolyte interphase, and then synergistically guide smooth Li nucleation/growth even at low temperatures. As a result, the obtained LMAs delivers a high areal capacity up to 15 mAh cm−2, ultralong lifespan (4800 cycles at 4 mA cm−2) with very low voltage hysteresis of ≈21 mV, a high practically available specific capacity of 863.9 mAh g−1 after 1000 cycles, and a long‐term stable behavior at low‐temperature operation. As coupling with the commercial LiNi1/3Co1/3Mn1/3O2 cathodes and common carbonate‐based electrolyte, the corresponding practical cells also possess an ultralong lifespan and outstanding low‐temperature functionality. This study not only presents an advanced carbon host candidate but also sheds new light on crucial design principles of carbon scaffolds for practically feasible rechargeable metal batteries.
Electrochemical analyses ofZrO2dispersoid incorporated poly (styrene‐methyl methacrylate) blend gel electrolytes for lithium‐ion battery
Authors: Ramachandran Murugesan , Subadevi Rengapillai , Rajkumar Palanisamy , Muthupradeepa Rajendran , Sivakumar Marimuthu
Published: June 2021

Zirconium oxide (ZrO2) filler is successfully synthesized with spherical morphology (particle size 170 nm) by co‐precipitation technique earlier. The as‐prepared ZrO2‐(bare, 3, 6, 9, and 12 wt%) is spread into the augmented poly(styrene‐co‐ methyl methacrylate) P(S‐MMA)‐ poly vinylidene fluoride (PVdF) (25:75 of 27 wt%)‐LiClO4(8 wt%)‐ ethylene carbonate and propylene carbonate (EC + PC) (1: 1 of 65 wt%) system. The solution casting technique is employed throughout the process. The structural, morphology, thermal and ionic conducting behavior of sample are examined. The highest conductivity is 1.2 × 10−2S cm−1at 303 K for P(S‐MMA)‐PVdF (25:75 of 27 wt%) LiClO4(8 wt%)‐ EC + PC (65 wt%) +6 wt% ZrO2system. The linear sweep voltammetry and the cyclic voltammetry tests are performed and the results are discussed. The optimized electrolyte is used to make the LiFePO4/CGPE/Li confined 2032 coin cell couple. It holds the discharge capacity of 144 mAh g−1at rate of 0.1 C with 88% coulombic efficiency.
Catalytic effect of alkali and alkaline earth metals on fast pyrolysis pre‐treatment of agricultural waste
Authors: Alcazar‐Ruiz Angel , Ortiz María Luz , Sanchez‐Silva Luz , Dorado Fernando
Published: June 2021

The catalytic effect of mineral components (K, Ca, Mg and Na), after pre‐treatment by water leaching and adding NaCl, was evaluated in fast pyrolysis with the biomass of four types of agricultural waste (olive pomace, nutshell, almond shell, and pistachio shell). Water leaching proved to be effective at reducing mineral content in the raw materials, especially in terms of removing K. As a consequence, there was lower decarboxylation activity during fast pyrolysis, and a lower yield of phenolic compounds was obtained. The effect of adding NaCl was evaluated by varying its ratio in the blend (1, 3 and 5 wt%) and it promoted cracking and dehydration reactions, favoring the formation of light molecular‐weight compounds as carboxylic acids. © 2021 The Authors. Biofuels, Bioproducts and Biorefining published by Society of Industrial Chemistry and John Wiley & Sons Ltd.
Model‐based control for column‐based continuous viral inactivation of biopharmaceuticals
Authors: Hong Moo Sun , Lu Amos E. , Ou Rui Wen , Wolfrum Jacqueline M. , Springs Stacy L. , Sinskey Anthony J. , Braatz Richard D.
Published: June 2021

Batch low‐pH hold is a common processing step to inactivate enveloped viruses for biologics derived from mammalian sources. Increased interest in the transition of biopharmaceutical manufacturing from batch to continuous operation resulted in numerous attempts to adapt batch low‐pH hold to continuous processing. However, control challenges with operating this system have not been directly addressed. This article describes a low‐cost, column‐based continuous viral inactivation system constructed with off‐the‐shelf components. Model‐based, reaction‐invariant pH controller is implemented to account for the nonlinearities with Bayesian estimation addressing variations in the operation. The residence time distribution is modeled as a plug flow reactor with axial dispersion in series with a continuously stirred tank reactor, and is periodically estimated during operation through inverse tracer experiments. The estimated residence time distribution quantifies the minimum residence time, which is used to adjust feed flow rates. Controller validation experiments demonstrate that pH and minimum residence time setpoint tracking and disturbance rejection are achieved with fast and accurate response and no instability. Viral inactivation testing demonstrates tight control of logarithmic reduction values over extended operation. This study provides tools for the design and operation of continuous viral inactivation systems in service of increasing productivity, improving product quality, and enhancing patient safety.
AAP recommends COVID vaccines
Authors: Knopf Alison
Published: June 2021

In May the American Academy of Pediatrics (AAP) recommended the following COVID‐19 vaccinations.
How one treatment program uses value‐based contracting
Authors: Knopf Alison
Published: June 2021

Many parents want to see their young adult children, and even teenagers, in residential treatment. But they may not be able to afford it, especially if their insurance company won't pay. Some treatment providers have figured out how to work with insurance companies to get that payment, and value‐based contracting (VBC) is one way to do it.
Fragment‐Based Drug Discovery for RNA Targets
Authors: Lundquist Kasper P. , Panchal Vipul , Gotfredsen Charlotte H. , Brenk Ruth , Clausen Mads H.
Published: June 2021

Rapid development within the fields of both fragment‐based drug discovery (FBDD) and medicinal targeting of RNA provides possibilities for combining technologies and methods in novel ways. This review provides an overview of fragment‐based screening (FBS) against RNA targets, including a discussion of the most recently used screening and hit validation methods such as NMR spectroscopy, X‐ray crystallography, and virtual screening methods. A discussion of fragment library design based on research from small‐molecule RNA binders provides an overview on both the currently limited guidelines within RNA‐targeting fragment library design, and future possibilities. Finally, future perspectives are provided on screening and hit validation methods not yet used in combination with both fragment screening and RNA targets.
Genome‐Wide Identification of DNase I Hypersensitive Sites in Plants
Authors: Wang Yankun , Wang Kai
Published: June 2021

DNase I hypersensitive site (DHS) mapping combined with high‐throughput sequencing (DNase‐seq) enables the identification of cis‐regulatory DNA elements (CREs) genome wide. However, despite the wide applications of DNase‐seq in plants, its application to the highly repetitive genomes of plants has lagged. Here, we describe a modified DNase‐seq method, making it more practical for application to plants with genomes enriched with repetitive DNA. This approach adopts a double‐hit‐based strategy, in which small (<250‐bp) DNA fragments digested by DNase I are selected and used for sequencing library construction. Using these protocols, we have conducted DNase‐seq in plants with high content of repetitive DNA, including maize, sugarcane, and tetraploid cotton. Genome‐wide maps of DHS and CREs have been created using these DNase‐seq datasets. © 2021 Wiley Periodicals LLC.

Basic Protocol 1: Nuclei isolation

Basic Protocol 2: DNase I digestion

Basic Protocol 3: Target DNA isolation

Basic Protocol 4: Library construction and validation
Fetal growth and spontaneous preterm birth in high‐altitude pregnancy: A systematic review, meta‐analysis, and meta‐regression
Authors: Grant Imogen D. , Giussani Dino A. , Aiken Catherine E.
Published: June 2021

Objective

To understand the relationship between birth weight and altitude to improve health outcomes in high‐altitude populations, to systematically assess the impact of altitude on the likelihood of low birth weight (LBW), small for gestational age (SGA), and spontaneous preterm birth (sPTB), and to estimate the magnitude of reduced birth weight associated with altitude.

Methods

PubMed, OvidEMBASE, Cochrane Library, Medline, Web of Science, and clinicaltrials.gov were searched (from inception to November 11, 2020). Observational, cohort, or case‐control studies were included if they reported a high altitude (>2500 m) and appropriate control population.

Results

Of 2524 studies identified, 59 were included (n = 1 604 770 pregnancies). Data were abstracted according to PRISMA guidelines, and were pooled using random‐effects models. There are greater odds of LBW (odds ratio [OR] 1.47, 95% confidence interval [CI] 1.33–1.62, P < 0.001), SGA (OR 1.88, 95% CI 1.08–3.28, P = 0.026), and sPTB (OR 1.23, 95% CI 1.04–1.47, P = 0.016) in high‐ versus low‐altitude pregnancies. Birth weight decreases by 54.7 g (±13.0 g, P < 0.0001) per 1000 m increase in altitude. Average gestational age at delivery was not significantly different.

Conclusion

Globally, the likelihood of adverse perinatal outcomes, including LBW, SGA, and sPTB, increases in high‐altitude pregnancies. There is an inverse relationship between birth weight and altitude. These findings have important implications for the increasing global population living at altitudes above 2500 m.
Laser‐induced cavitation in plasmonic nanoparticle solutions: A comparative study between gold and titanium nitride
Authors: Sabzeghabae Ariana Nushin , Berrospe‐Rodriguez Carla , Mangolini Lorenzo , Aguilar Guillermo
Published: June 2021

In this work, we present an extensive comparative study between novel titanium nitride nanoparticles (TiN NPs) and commercial gold nanorods (GNR), both dispersed in water and exposed to a pulsed laser‐induced cavitation process. The optical density, shockwave emission, and bubble formation of these solutions were investigated using shadowgraphy, spatial transmittance modulation, and acoustic measurements. TiN nanoparticle solutions exhibited high stability undser a periodic nanosecond pulsed‐laser irradiation, making these nanomaterials promising agents for high‐power applications. In addition, they demonstrated a stronger nonlinear absorption compared to the GNR solutions, and plasma formation at lower laser energies. This study advances our understanding of the optical properties of TiN and discusses significant differences compared to gold, with important implications for future applications of this material in water treatment, nonlinear signal converting, and laser‐induced cavitation for medical implementations, among others.
Estimating Abundance and Simulating Fertility Control in a Feral Burro Population
Authors: Gedir Jay V. , Cain James W. , Lubow Bruce C. , Karish Talesha , Delaney David K. , Roemer Gary W.
Published: June 2021

Overabundant populations of feral equids are negatively affecting rangelands in the western United States. To better manage these populations, robust estimates of abundance and demographic rates and cost‐effective methods of reducing abundance are necessary. From August 2015 to April 2017, we estimated the abundance of feral burros (Equus asinus) at the Fort Irwin National Training Center (NTC; California, USA) using a double‐observer‐sightability aerial survey method; captured, radio‐collared, and inoculated female burros with porcine zona pellucida (PZP), an immunocontraceptive control agent; estimated female demographic rates; and used matrix population models to simulate how changes in demographic and PZP delivery rates would influence burro abundance. We estimated there were 690 (95% CI = 618–752) feral burros within the surveyed area, but these are part of a much larger population that is not geographically isolated from those in the survey area. Sighting probabilities ranged from 0.19–0.98 and were most strongly influenced by distance from observer and group size. We estimated age‐specific demographic rates at the NTC and compiled mean rates across burro populations in arid environments from the literature. Mean fecundity varied from 0.17 to 0.58 foals/adult female with younger females having lower fecundity. Mean survival was 0.90 for foals, 0.98 for yearlings, and 0.96 for adults. The PZP vaccine treatment strategies that suppressed fertility for up to 10 years predicted that burro abundance would be reduced by 67–88% after 15 years (compared with no treatment), but none of these strategies resulted in population extirpation. Population growth rates shifted from increasing to decreasing at adult survival rates below 0.84 and the population was predicted to become extirpated when adult survival declined to <0.60. In the absence of other methods to reduce burro numbers, our findings indicate that current formulations of PZP immunocontraception, which require multiple doses, would be inadequate for controlling population growth rates at the NTC. Our fieldwork also highlighted the difficulty of administering PZP vaccination to large, free‐ranging animals. Development of longer‐term fertility reduction agents or more efficient vaccine delivery techniques would likely improve the efficacy of fertility control for overabundant ungulate populations. Lack of geographic closure (physical barriers to migration) further complicated efforts to reduce burro numbers. © 2021 The Wildlife Society.
Influence of aluminum phosphate on the tribocorrosion performance of chemically bonded phosphate ceramic coatings
Authors: Wang Jianyu , Bian Da , Liu Yaxuan , Zhao Yongwu , Tang Hao
Published: June 2021

In this study, chemically bonded phosphate ceramic coatings (CBPCCs) with different contents of aluminum phosphate (AP) are prepared on stainless steel (AISI 304L). Differential scanning calorimetry, X‐ray diffraction, contact angle test, and a tribocorrosion experiment are carried out to clarify the role of AP in the tribocorrosion performance of CBPCCs. The results show that, with the increase in the AP content, the enthalpy of curing increases because of the greater formation of the bonding phase AlPO4. Both in static corrosion and in tribocorrosion, the corrosion current density of CBPCCs achieves the lowest value when the weight ratio of AP to polytetrafluoroethylene is about 0.78. Additionally, the influence mechanism of AP on tribocorrosion is clarified. AlPO4 from the reaction between AP and Al2O3 has excellent mechanical properties and can enhance the wear resistance of CBPCCs by reducing the mechanical wear and the increased wear due to corrosion. The alumina particles wrapped by AlPO4 can form a dense and smooth surface and change the direction of electrolyte propagation, which leads to the increase in the tribocorrosion resistance of CBPCCs.