bluuebunny/crossref_metadata_2025 huggingface dataset:
Control of mitochondrial respiration
Authors: Tager J.M. , Wanders R.J.A , Groen A.K. , Kunz W. , Bohnensack R. , Küster U. , Letko G. , Böhme G. , Duszynski J. , Wojtczak L.
Published: July 2002

The control theory of Kacser and Burns [in: Rate Control of Biological Processes (Davies, D.D. ed) pp. 65–104, Cambridge University Press, London, 1973] and Heinrich and Rapoport ([Eur. J. Biochem. (1974) 42, 97‐105] has been used to quantify the amount of control exerted by different steps on mitochondrial oxidative phosphorylation in rat‐liver mitochondria. Inhibitors were used to manipulate the amount of active enzyme. The control strength of the adenine nucleotide translocator was measured by carrying out titrations with carboxyatractyloside. In state 4, the control strength of the translocator was found to be zero. As the rate of respiration was increased by adding hexokinase, the control strength of the translocator increased to a maximum value of ∼30% at ∼80% of state 3 respiration. In state 3, control of respiration is distributed between a number of steps, including the adenine nucleotide translocator, the dicarboxylate carrier and cytochrome c oxidase. The measured values for the distribution of control agree very well with those calculated with the aid of a model for mitochondrial oxidative phosphorylation developed by Bohnensack [Biochim. Biophys. Acta (1982) 680, 271–280].
NOE data at 500 MHz reveal the proximity of phenyl and tyrosine rings in enkephalin
Authors: Gupta Goutam , Sarma M.H. , Sarma R.H. , Dhingra M.M.
Published: July 2002

Met5‐enkephalin ‐ a pentapeptide (Tyr‐Gly‐Gly‐Phe‐Met) ‐ can exist in two possible folded arrangements with a rigid two‐hydrogen‐bonded network. In one arrangement, a Gly 2‐Gly 3 β‐bend is formed and in the other a Gly 3‐Phe 4 β‐bend. The two conformations are distinguished by the spatial relation of Tyr 1 and Phe 4: in the Gly 2‐Gly 3 β‐bend, Tyr 1 and Phe 4 can be brought close to each other while in the Gly 3‐Phe 4 β‐bend they are far apart (⪢5 Å). We have utilized one‐dimensional (1D) nuclear Overhauser effect (NOE) measurements between the ring protons of Tyr 1 and Phe 4 to determine their proximity. The NOE data clearly show that a pair protons, one each from Tyr 1 and Phe 4, are as close as 3.3 Å while other inter‐proton distances are beyond 4.5 Å. Therefore, we propose the presence of a Gly 2‐Gly 3 β‐bend (in which Tyr 1 and Phe 4 are spatially close) for Met5‐enkephalin in solution. The structure of Met5‐enkephalin in solution is very similar to the single crystal structure of Leu5‐enkephalin and tends to explain the biological activity data of several modified enkephalins.
Identification by molecular cloning of two forms of the α‐subunit of the human liver stimulatory (Gs) regulatory component of adenylyl cyclase
Authors: Mattera Rafael , Codina Juan , Crozat Ann , Kidd Vincent , Woo Savio L.C. , Birnbaumer Lutz
Published: July 2002

Two DNA molecules complementary to human liver mRNA coding for the α‐subunit of the stimulatory regulatory component Gs of adenylyl cyclase were cloned. One of the two forms is a full‐length cDNA of 1614 nucleotides plus a poly(A) tail of 59 nucleotides. The deduced sequence of 394 amino acids encoded by its open reading frame is essentially identical to that of the α‐subunits of Gs identified by molecular cloning from bovine adrenals, bovine brain and rat brain. Two independent clones of the other type of cDNA were isolated. Both were incomplete, beginning within the open reading frame coding for the αs polypeptide. One codes for amino acids 5 through 394 and the other for amino acids 48 through 394 of the above described cDNA of 1614 nucleotides, and both have the identical 3'‐untranslated sequence. They differ from the first cDNA, however, in that they lack a stretch of 42 nucleotides (numbers 214 through 255) and have nucleotides 213 (G) and 256 (G) replaced with C and A, respectively. This results in a predicted amino acid composition of another α‐subunit of Gs that is shorter by 14 amino acids and contains two substitutions (Asp for Glu and Ser for Gly) at the interface between the deletion and the unchanged sequence. We call the smaller subunit αs1 and the larger αs2. This is the first demonstration of a structural heterogeneity in αs, subunits that is due to a difference in amino acid sequence.
Evolution of an inducible penicillin‐target protein in methicillin‐resistant Staphylococcus aureus by gene fusion
Authors: Song Min Dong , Wachi Masaaki , Doi Masaki , Ishino Fumitoshi , Matsuhashi Michio
Published: July 2002

A new β‐lactam‐inducible penicillin‐binding protein (PBP) that has extremely low affinity to penicillin and most other β‐lactam antibiotics has been widely found in highly, β‐lactam(methicillin)‐resistant Staphylococcus aureus (MRSA). The gene for this protein was sequenced and the nucleotide sequence in its promoter and close upstream area was found to show close similarity with that of staphylococcal penicillinase, while the amino acid sequence over a wide range of the molecule was found to be similar to those of two PBPs of Escherichia coli, the shape‐determining protein (PBP 2) and septum‐forming one (PBP 3). Probably the MRSA PBP (M
r 76462) evolved by recombination of two genes: an inducible type I penicillinase gene and a PBP gene of a bacterium, causing the formation of a β‐lactam‐inducible MRSA PBP.
Effect of Mg2+on excitation energy transfer between LHC II and LHC I in a chlorophyll‐protein complex
Authors: Williams Richard S. , Allen John F. , Brain Anthony P.R. , Ellis R.John
Published: July 2002

A chlorophyll‐protein preparation has been isolated from the thylakoid membranes ofPisum sativumL. by the use of Triton X‐100 in the presence of a Tris‐HCl buffer. Analysis of this preparation by means of SDS‐PAGE and freeze‐fracture electron microscopy indicates that it contains the reaction centre complex of photosystem I (PS I) and its associated peripheral light‐harvesting complex (LHC I), together with the peripheral light‐harvesting complex of PS II (LHC II). The reaction centre complex of PS II is absent from this preparation. The polypeptide composition of the complex is similar to that of one previously isolated from barley [(1987) Eur. J. Biochem. 163, 221–2301. Fluorescence spectroscopy of the preparation at 77 K indicates that excitation of chlorophyllbat 472 nm (LHC II) gives fluorescence emission at 735 nm from LHC I, thereby indicating excitation energy transfer between the two complexes. The extent of excitation energy transfer from LHC II to LHC I is increased by the absence of Mg2+from the medium, a phenomenon similar to effects of Mg2+depletion promoting ‘spillover’ of excitation energy from PS II to PS I in chloroplast thylakoid membranes.
Evidence for a dipyrromethane cofactor at the catalytic site of E. coli porphobilinogen deaminase
Authors: Jordan Peter M. , Warren Martin J.
Published: July 2002

Porphobilinogen deaminase isolated from Escherichia coli is shown to contain a dipyrromethane cofactor (DPMC) linked covalently to the enzyme. The structure of the cofactor is proposed on the basis of its reaction with Ehrlich's reagent and from its chemical properties. The cofactor is involved in the binding of intermediates during the catalytic reaction but is not incorporated into the product preuroporphyrinogen, E. coli strains containing the cloned porphobilinogen deaminase gene (hemC) when grown on 5‐amino[14C]‐levulinic acid incorporate 14C radioactivity specifically into the dipyrromethane cofactor of porphobilinogen deaminase.
Cloning a synthetic gene for human stefin B and its expression in E. coli
Authors: Jerala Roman , Trstenjak Mojca , Lenarčič Brigita , Turk Vito
Published: July 2002

A gene coding for human stefin B was synthesized by the solid‐phase phosphite method and cloned in the pUC8 cloning vector. The insert with the verified DNA sequence was subcloned into two expression vectors and expressed in E. coli as a fusion protein with β‐galactosidase and as a native protein. The CNBr cleaved fusion protein and the native recombinant stefin B were inhibitory to papain and reacted with antibodies against human stefin B.
A novel superfamily of nucleoside triphosphate‐binding motif containing proteins which are probably involved in duplex unwinding in DNA and RNA replication and recombination
Authors: Gorbalenya Alexander E. , Koonin Eugene V. , Donchenko Alexei P. , Blinov Vladimir M.
Published: July 2002

A statistically significant similarity was demonstrated between the amino acid sequences of 4 Escherichia coli helicases and helicase subunits, a family of non‐structural proteins of eukaryotic positive‐strand RNA viruses and 2 herpesvirus proteins all of which contain an NTP‐binding sequence motif. Based on sequence analysis and secondary structure predictions, a generalized structural model for the ATP‐binding core is proposed. It is suggested that all these proteins constitute a superfamily of helicases (or helicase subunits) involved in NTP‐dependent duplex unwinding during DNA and RNA replication and recombination.
The amino acid sequences of jacalin and the Maclura pomifera agglutinin
Authors: Young N.Martin , Johnston Rosemary A.Z. , Watson David C.
Published: July 2002

Amino acid sequences for the α‐chains of the Moraceae lectins, jacalin and Maclura pomifera agglutinin, were determined by protein sequencing. Both are 133 residues long and contain several genetically variant positions; the overall homology is 85%. A possible site for the known glycopeptide ot jacalin was located. The α‐chains have a conserved tryptophan residue that may be part of the binding‐site.
Rhizomucor miehei lipase remains highly active at water activity below 0.0001
Authors: Valivety Rao H. , Halling Peter J. , Macrae Alasdair R.
Published: July 2002

The lipase from Rhizomucor miehei adsorbed on polymer beads retains substantial catalytic activity even after exhaustive drying, and the use of dry box procedures to prevent entry of atmospheric water. Rates of esterification and transesterification (alcoholysis) were measured while stirred in hexane pre‐dried to similar low water activity (a
w). The rate of dodecyl decanoate synthesis was over 30% of that at the optimum (a
w 0.55) after drying with anhydrous CuSO4 or MgO (a
w<10−4). Freshly reactivated molecular sieve could cause a further reduction in, but not elimination of, activity.
Timing of palmitoylation of influenza virus hemagglutinin
Authors: Veit Michael , Schmidt Michael F.G.
Published: July 2002

The timing of the attachment of fatty acids to the hemagglutinin (HA) of influenza A virus was studied. Treatment of virus infected cells with brefeldin A (BFA), a drug which blocks intracellular transport along the exocytic pathway at a pre‐Golgi site, does not prevent palmitoylation of HA. The relationship of HA‐palmitoylation to the oligomerisation and to the proteolytical cleavage of the protein revealed that the uncleaved trimer of HA is the substrate for the acylating enzyme in virus infected cells. The results are discussed with regard to the intracellular site of palmitoylation.
The rates of proton uptake and electron transfer at the reducing side of photosystem II in thylakoids
Authors: Haumann Michael , Junge Wolfgang
Published: July 2002

Proton and electron transfer at the reducing side of photosystem II of green plants was studied under flashing light, the former at improved time resolution by using Neutral red. The rates of electron transfer within QAFeQB were determined by pump‐probe flashes through electrochromic transients. The extent of proton binding was about 1 H+/e−. The rates of proton transfer were proportional to the concentration of Neutral red (collisional transfer), whereas the rates of electron transfer out of Q−
A and from QAFeQ−
B to the cytochrome b
6
f complex were constant. The half‐rise times of electron transfer (τe) and the apparent times of proton binding (τh) at 30 μM Neutral red were: Q−
A ⇒ FeIIIQB (τe ⩽ 100 μs, τ, 230 μs); Q−
A ⇒ FeIIQB (τe = 150 μs, τh = 760 μs); and Q−
A ⇒ FeIIQ−
B (τe = 620 μs, τh = 310 μs).
Complement assembly of two fragments of the streptococcal protein G B1 domain in aqueous solution
Authors: Kobayashi Naohiro , Honda Shinya , Yoshii Hirofumi , Uedaira Hatsuho , Munekata Eisuke
Published: July 2002

We examined the complementation of various pairs of fragments derived from the streptococcal protein G B1 domain by NMR and CD. Most were not associated; however, one pair of fragments (1–40) and (41–56) interacted sufficiently enoughto regenerate a stable 1:1 complex, K
d = 9 × 10−6M. A 2D‐NMR analysis showed that the structure of the complex resembled that of native domain. Here we discuss the complementation from the viewpoint of the folding pathway of the protein.
PCR cloning and expression analysis of a cDNA encoding a pectinacetylesterase from Vigna radiata L
Authors: Breton Christelle , Bordenave Marianne , Richard Luc , Pernollet Jean Claude , Huet Jean Claude , Pérez Serge , Goldberg Renée
Published: July 2002

A cDNA clone encoding a pectinacetylesterase (PAE) was isolated from 3‐day‐old mung bean seedlings using PCR‐based techniques. Degenerate oligonucleotide primers were designed according to the N‐terminus and internal peptides from the purified PAE. The full‐length clone of 1453 bp codes for a signal peptide of 24 amino acids and a mature protein of 375 amino acids. The M
r and the pI of the cDNA‐deduced amino acid sequence agree with the values estimated for the purified enzyme. No significant sequence identity between the PAE and any known protein could be found in the databases. Northern analysis revealed developmentally regulated expression of the mRNA in mung been seedlings.
Schizophrenic patients' retrospective attitudes regarding involuntary psychopharmacological treatment and restraint
Authors: Naber D , Kircher T , Hessel K
Published: July 2002

The considerable debate about the justification of coercive measures in psychiatry includes medical, ethical, legal and political arguments, patients' subjective experience of involuntary injections or restraint is barely investigated. A semi-structured interview was used to evaluate retrospective attitudes in 40 (32 schizophrenic) patients, treated involuntarily with injection of neuroleptic drugs or restrained. Of these patients, 48% rated these measures as necessary or positive, 23% as negative, and 30% were indifferent. Only patients with good insight into their disease were able to accept the involuntary treatment retrospectively as positive. Reasons for treatment refusal were inadequacy of the measures (58%), negative previous experience with neuroleptic drugs (47%), eg, akathisia, and reservations against the medical system itself (28%). ‘Fear’ and ‘powerlessness’ were the predominant feelings which patients experienced when confronted with coercive measures. Restraint was more disliked than injections. The results support the notion that disease concept and the ability to acknowledge mental illness are major factors influencing a schizophrenic patient's decision to accept of refuse treatment.
Existence of a plant tyrosylprotein sulfotransferase: novel plant enzyme catalyzing tyrosine O‐sulfation of preprophytosulfokine variants in vitro
Authors: Hanai Hidetoshi , Nakayama Daisuke , Yang Heping , Matsubayashi Yoshikatsu , Hirota Yuki , Sakagami Youji
Published: July 2002

An in vitro assay system to detect tyrosylprotein sulfotransferase (TPST) activity of higher plant cells was established, using synthetic oligopeptides based on the deduced amino acid sequence of a phytosulfokine‐α (PSK‐α) precursor. TPST activity was found in microsomal membrane fractions of rice, asparagus and carrot cells and it was confirmed that acidic amino acid residues adjacent to the tyrosine residues of acceptor peptides were essential to the sulfation reaction. The asparagus TPST exhibited a broad pH optimum of 7.0–8.5, required manganese ions for maximal activity and appeared to be a membrane‐bound protein localized in the Golgi apparatus. These enzymes should be defined as a new class of plant sulfotransferases that catalyze tyrosine O‐sulfation of a PSK‐α precursor and other unknown proteins.
F‐ATPase: specific observation of the rotating c subunit oligomer of EFoEF1
Authors: Pänke Oliver , Gumbiowski Karin , Junge Wolfgang , Engelbrecht Siegfried
Published: July 2002

The rotary motion in response to ATP hydrolysis of the ring of c subunits of the membrane portion, Fo, of ATP synthase, FoF1, is still under contention. It was studied with EFoEF1 (Escherichia coli) using microvideography with a fluorescent actin filament. To overcome the limited specificity of actin attachment through a Cys‐maleimide couple which might have hampered the interpretation of previous work, we engineered a ‘strep‐tag’ sequence into the C‐terminal end of subunit c. It served (a) to purify the holoenzyme and (b) to monospecifically attach a fluorescent actin filament to subunit c. EFoEF1 was immobilized on a Ni‐NTA‐coated glass slide by the engineered His‐tag at the N‐terminus of subunit β. In the presence of MgATP we observed up to five counterclockwise rotating actin filaments per picture frame of 2000 μm2 size, in some cases yielding a proportion of 5% rotating over total filaments. The rotation was unequivocally attributable to the ring of subunit c. The new, doubly engineered construct serves as a firmer basis for ongoing studies on torque and angular elastic distortions between F1 and Fo.
A potential mechanism for regulating myosin I binding to membranes in vivo
Authors: Senda Shunji , Titus Margaret A
Published: July 2002

Myosin Is are associated with specific membranes, however, the mechanism for regulating their intracellular localization is unclear. As a first step towards understanding this mechanism, membrane rebinding assays using Dictyostelium myoB were performed. Crude, cytosolic myoB bound to intact, but not to NaOH‐treated plasma membranes. In contrast, partially purified myoB binds to both intact and NaOH‐treated plasma membranes. Chemical cross‐linking of cytosolic myoB yielded several products, whereas none were found with the partially purified myoB. These results suggest a model where proteins regulating the specific binding of myoB to the plasma membrane may exist both in the cytosol and on the plasma membrane.
Use of ruthenium red as an inhibitor of mitochondrial Ca2+ uptake in single rat cardiomyocytes
Authors: Griffiths Elinor J
Published: July 2002

With the current resurgence of interest in the role of mitochondrial [Ca2+] in energy production and cellular Ca2+ signalling, ruthenium red (RR) is being increasingly used as an inhibitor of mitochondrial Ca2+ uptake. In the present study, the effects of RR on cell and mitochondrial [Ca2+], and on cell contractility were determined in isolated rat ventricular myocytes subjected to adrenergic and electrical stimulation. At low concentrations, 0–1 μM, RR inhibited mitochondrial Ca2+ uptake but this was a secondary effect due to a reduced total intracellular [Ca2+], a conclusion supported by the ability of RR to inhibit cell shortening. 5 μM RR completely inhibited cell contraction, whereas higher concentrations, 10–25 μM, induced spontaneous Ca2+ oscillations and contractile waves. These results indicate that great care must be taken when using RR in intact cells, and in interpreting any effects as resulting from a primary inhibition of mitochondrial Ca2+ uptake.
Cysteine‐153 is required for redox regulation of pea chloroplast fructose‐1,6‐bisphosphatase
Authors: Jacquot Jean-Pierre , Lopez-Jaramillo Javier , Miginiac-Maslow Myroslawa , Lemaire Stéphane , Cherfils Jacqueline , Chueca Ana , Lopez-Gorge Julio
Published: July 2002

Chloroplastic fructose‐1,6‐bisphosphatases are redox regulatory enzymes which are activated by the ferredoxin thioredoxin system via the reduction/isomerization of a critical disulfide bridge. All chloroplastic sequences contain seven cysteine residues, four of which are located in, or close to, an amino acid insertion region of approximately 17 amino acids. In order to gain more information on the nature of the regulatory site, five cysteine residues (Cys49, Cys153, Cys173, Cys178 and Cys190) have been modified individually into serine residues by site‐directed mutagenesis. While mutations C173S and C178S strongly affected the redox regulatory properties of the enzyme, the most striking effect was observed with the C153S mutant which became permanently active and redox independent. On the other hand, the C190S mutant retained most of the properties of the wild‐type enzyme (except that it could now also be partially activated by the NADPH/NTR/thioredoxin h system). Finally, the C49S mutant is essentially identical to the wild‐type enzyme. These results are discussed in the light of recent crystallographic data obtained on spinach FBPase [Villeret et al. (1995) Biochemistry 34, 4299–4306].
Human lactase‐phlorizin hydrolase expressed in COS‐1 cells is proteolytically processed by the lysosomal pathway
Authors: Wüthrich Marcel , Sterchi Erwin E.
Published: July 2002

Lactase‐phlorizin hydrolase (LPH) (EC 3.2.1.23/62), a major glycoprotein of the microvillus membrane of human small intestinal epithelial cells (enterocytes), is vital for the digestion of lactose during early infancy. The enzyme is synthesized in enterocytes as a single‐chain precursor and subsequently proteolytically processed to the mature microvillus membrane‐bound form. Because it has been reported that COS‐1 cells were not able to proteolytically process LPH to the mature protein, these cells have been used as a model system to study potential roles of different proteases. COS‐1 cells transfected with a full‐length cDNA for human LPH synthesized enzymatically active enzyme. Immunoprecipitation of the expressed glycoproteins and their subsequent analysis by SDS‐PAGE showed synthesis of two polypeptide species having apparent molecular masses of 210 and 220 kDa, respectively, corresponding to the high‐mannose (pro‐LPHh) form and the complex glycosylated (pro‐LPHc) form of the LPH precursor. Surprisingly, an additional polypeptide species corresponding in size to the mature LPH found in human intestinal cells was also detected after longer chase periods. The source of this species was clearly pro‐LPH, as its formation was inhibited by Brefeldin A. The cleaved form of LPH was not found on the cell surface; furthermore, its formation was prevented by an inhibitor of lysosomal function. We conclude from these data that in transfected COS‐1 cells pro‐LPH is transported to the cell surface, from which it is internalised and enters the lysosomal pathway, where proteolytic cleavage leads to a molecule not unlike mature LPH.
Solution structure of robustoxin, the lethal neurotoxin from the funnel‐web spider Atrax robustus
Authors: Pallaghy Paul K , Alewood Dianne , Alewood Paul F , Norton Raymond S
Published: July 2002

The solution structure of robustoxin, the lethal neurotoxin from the Sydney funnel‐web spider Atrax robustus, has been determined from 2D 1H NMR data. Robustoxin is a polypeptide of 42 residues cross‐linked by four disulphide bonds, the connectivities of which were determined from NMR data and trial structure calculations to be 1–15, 8–20, 14–31 and 16–42 (a 1–4/2–6/3–7/5–8 pattern). The structure consists of a small three‐stranded, anti‐parallel β‐sheet and a series of interlocking γ‐turns at the C‐terminus. It also contains a cystine knot, thus placing it in the inhibitor cystine knot motif family of structures, which includes the ω‐conotoxins and a number of plant and animal toxins and protease inhibitors. Robustoxin contains three distinct charged patches on its surface, and an extended loop that includes several aromatic and non‐polar residues. Both of these structural features may play a role in its binding to the voltage‐gated sodium channel.
Do transmembrane protein superfolds exist?
Authors: Jones David T
Published: July 2002

A reliable and widely used transmembrane protein structure prediction algorithm was applied to five representative genomic sequence data sets in order to re‐examine the hypothesis that in contrast to globular proteins there are no favored transmembrane protein fold families. When the number of predicted membrane spanning segments and the topology of these segments is taken into account then definite biases are observed which suggest that certain transmembrane topologies are significantly more common than others.
TRUNDD, a new member of the TRAIL receptor family that antagonizes TRAIL signalling
Authors: Pan Guohua , Ni Jian , Yu Guo-liang , Wei Ying-Fei , Dixit Vishva M
Published: July 2002

TRAIL/Apo‐2L induces rapid apoptosis of a variety of tumor cell lines. A family of tumor necrosis factor receptor‐related molecules have been identified as receptors for TRAIL. Herein, we report the identification of another member of the TRAIL receptor family, TRUNDD (TRAIL receptor with a truncated death domain). The TRUNDD transcript was detected in multiple human tissues. TRUNDD is highly homologous to all known TRAIL receptors and has an extracellular TRAIL‐binding domain but lacks a functional intracellular death domain and does not induce apoptosis. Consistent with an inhibitory role, ectopic expression of TRUNDD attenuated TRAIL‐induced apoptosis in mammalian cells.
Composition of parental mitochondrial DNA in cloned bovine embryos
Authors: Steinborn Ralf , Zakhartchenko Valeri , Jelyazkov Jivko , Klein Dieter , Wolf Eckhard , Müller Mathias , Brem Gottfried
Published: July 2002

We have investigated parental mitochondrial DNA (mtDNA) in cloned bovine embryos obtained by intraspecific cytoplast‐blastomere fusion. Analysis of two‐cell to blastocyst stage embryos revealed that in contrast to the exclusion of paternal (sperm) mtDNA during sexual inheritance in the cytoplast‐blastomere fusion complexes, there was mixing and co‐existence of parental mtDNA. The mixing of mtDNA was non‐balanced with the minority deriving from the blastomere. The constant content of mtDNA during embryogenesis until the blastocyst stage suggesting an absence of mtDNA replication was shown for conventional `in vitro fertilised' (IVF) embryos and for cloned embryos. The ratio of parental mtDNA was in accordance with the estimated quantitative participation of mtDNA from the fusion partners.
The murine gap junction gene connexin36 is highly expressed in mouse retina and regulated during brain development
Authors: Söhl Goran , Degen Joachim , Teubner Barbara , Willecke Klaus
Published: July 2002

A new gap junction gene isolated from rat brain cDNA, mouse retina cDNA and mouse genomic DNA is called connexin36, since it codes for a connexin protein of 321 amino acids corresponding to the theoretical molecular mass of 36 045 kDa (rat) and 36 084 kDa (mouse). Only one amino acid residue differs between rat and mouse connexin36. In the single murine connexin36 gene, an 1.14‐kb intron interrupts the coding region, similar as in the homologous skate connexin35 gene. Because of this unique feature, mouse connexin36 differs from the other 13 murine connexin genes and is suggested to form a new δ subclass of connexins. Connexin36 mRNA (2.9 kb) is highly expressed in adult retina and less abundant in brain where it gradually increased during fetal development until day 7 post partum, and decreased thereafter.
Plasma membrane NADH‐coenzyme Q0 reductase generates semiquinone radicals and recycles vitamin E homologue in a superoxide‐dependent reaction
Authors: Kagan Valerian E , Arroyo Antonio , Tyurin Vladimir A , Tyurina Yulia Y , Villalba Jose M , Navas Placido
Published: July 2002

We investigated the ability of plasma membrane CoQ reductase (PMQR) purified from pig liver to reduce phenoxyl radicals of a vitamin E homologue, Trolox. We report that NADH‐driven one‐electron reduction of CoQ0 catalyzed by PMQR produced CoQ0 semiquinone radical and CoQ0H2. These in turn, recycle vitamin E homologue, Trolox, via reducing its phenoxyl radical. A significant part of NADH/PMQR‐catalyzed reduction of CoQ0 (and Trolox recycling) was superoxide‐dependent. Overall, our results demonstrate that PMQR in the model system used can act as an antioxidant enzyme that recycles water‐soluble homologues of coenzyme Q and vitamin E.
Regulation of CFTR ion channel gating by MgATP
Authors: Aleksandrov Andrei A. , Riordan John R.
Published: July 2002

Single channel currents of wild‐type CFTR reconstituted in lipid bilayers were recorded to study the temperature dependence of channel gating between +20°C and +40°C. The opening of the channel was highly temperature dependent and required an activation energy of about 100 kJ/mol. Closing of the channel was only weakly temperature dependent with an activation energy close to that of diffusion in water. We found no significant difference in the free energy between the open and closed states. Most of the excess energy needed to activate channel opening is used to diminish the entropy of the open state. This structural reorganization is initiated by ATP binding followed by interconversion to the open channel structure as the CFTR‐ATP‐Mg complex passes to the transition state for hydrolysis. The energy of the CFTR‐ATP‐Mg interaction in the transition state is responsible for the CFTR ion channel opening rather than the energy of ATP hydrolysis. Channel closing is a diffusion limited process and does not require additional ATP binding.
Redox properties and electron paramagnetic resonance spectroscopy of the transition state complex of Azotobacter vinelandii nitrogenase
Authors: Spee J.H. , Arendsen A.F. , Wassink H. , Marritt S.J. , Hagen W.R. , Haaker H.
Published: July 2002

Nitrogenase is a two‐component metalloenzyme that catalyzes a MgATP hydrolysis driven reduction of substrates. Aluminum fluoride plus MgADP inhibits nitrogenase by stabilizing an intermediate of the on‐enzyme MgATP hydrolysis reaction. We report here the redox properties and electron paramagnetic resonance (EPR) signals of the aluminum fluoride‐MgADP stabilized nitrogenase complex of Azotobacter vinelandii. Complex formation lowers the midpoint potential of the [4Fe‐4S] cluster in the Fe protein. Also, the two‐electron reaction of the unique [8Fe‐7S] cluster in the MoFe protein is split in two one‐electron reactions both with lower midpoint potentials. Furthermore, a change in spin‐state of the two‐electron oxidized [8Fe‐7S] cluster is observed. The implications of these findings for the mechanism of MgATP hydrolysis driven electron transport within the nitrogenase protein complex are discussed.
Increased oxidative damage to all DNA bases in patients with type II diabetes mellitus
Authors: Rehman Almas , Nourooz-Zadeh Jaffar , Möller Wenke , Tritschler Hans , Pereira Paulo , Halliwell Barry
Published: July 2002

Gas chromatography‐mass spectrometry was used to measure the oxidative DNA damage in diabetic subjects and controls. Levels of multiple DNA base oxidation products, but not DNA base de‐amination or chlorination products, were found to be elevated in white blood cell DNA from patients with type II diabetes as compared with age‐matched controls. The chemical pattern of base damage is characteristic of that caused by an attack on DNA by hydroxyl radical. An increased formation of the highly reactive hydroxyl radical could account for many of the reports of oxidative stress in diabetic subjects. There was no evidence of an increased DNA damage by reactive nitrogen or chlorine species.
Distinct energy requirement for nuclear import and export of importin β in living cells
Authors: Kose Shingo , Imamoto Naoko , Yoneda Yoshihiro
Published: July 2002

Importin β can shuttle between the nucleus and cytoplasm through the nuclear pore complex (NPC). This study deals with the issue of how the energy is utilized during the NPC passage of importin β. In chilled or ATP‐depleted cells, importin β was transported into the nucleus, while the nuclear export of importin β was inhibited. Further, it was found that the nuclear export inhibition of importin β is not due to nuclear retention via binding to nucleoporins or nuclear importin α. These data show that the nuclear export of importin β involves energy‐requiring step(s) in living cells.
Assisted reproduction developments in the Islamic world
Authors: Serour G.I , Dickens B.M
Published: July 2002

A November 2000 workshop organized by the International Islamic Center for Population Studies and Research, Al‐Azhar University, Cairo, considered use of assisted reproduction technologies (ART) in the Islamic world. The workshop reinforced a 1997 recommendation that a Standing Committee for Shari'a Medical Ethics be constituted to monitor and assess developments in ART practice. Among issues the workshop addressed were equitable access to services for infertile couples of modest means, and regulation of standards of equipment and personnel that ART centers should satisfy to gain approval to offer services. Acceptable uses of preimplantation genetic diagnosis were proposed, and follicular maturation research in animals, including in vitro maturation and in vitro growth of oocytes, was encouraged, leading to human applications. Embryo implantation following a husband's death, induced postmenopausal pregnancy, uterine transplantation and gene therapy were addressed and human reproductive cloning condemned, but cloning human embryos for stem cell research was considered acceptable.
A morphometric study of maternal smoking on apoptosis in the syncytiotrophoblast
Authors: Marana H.R.C. , Andrade J.M. , Martins G.A. , Silva J.S. , Sala M.A. , Cunha S.P.
Published: July 2002

Objectives: To study syncytiotrophoblast apoptosis in the placenta of smoking and non‐smoking pregnant women. Methods: Twelve neonates, pregnancies and placentas were available for study. Eight mothers smoked during pregnancy and the remaining four were non‐smokers used as control subjects. The main outcome measure was the apoptotic syncytiotrophoblast index for each group. Apoptosis was detected by immunohistochemistry using the TUNEL method and quantitatively measured using a Merz grid. The apoptotic syncytiotrophoblast index was calculated as the ratio of mean apoptotic labeling to percent terminal villus area using high‐power field microscopy. Results: Significant differences in apoptotic syncytiotrophoblast index were observed between the control group (15.06 ± 3.72) and the smoker group (1.66 ± 1.74) (P < 0.0001, Mann‐Whitney test), but no differences were detected in clinical or morphometric data between groups. Conclusions: The human placental syncytiotrophoblast undergoes apoptosis and this process is associated with inhibition of apoptosis by the smoking habit. The same way as the presence of trophoblast apoptosis is associated with modifications of the maternal‐fetal exchange, the inhibitory effect of the smoking habit on syncytiotrophoblast could be responsible for the poor prognosis of pregnancy in the presence of maternal smoking.
Detection of human papillomavirus types in cervical adenocarcinoma by the polymerase chain reaction
Authors: Lee M.F. , Chang M.C. , Wu C.H.
Published: July 2002

To determine the human papillomavirus (HPV) types in cervical adenocarcinoma of patients from Taiwan. Methods: DNA was extracted from fixed tissues and polymerase chain reaction was performed in conjunction with a unique probe, pRSA I, allowing simultaneous detection of HPV types 6, 11, 16, 18, 31 and 33 from amplified HPV DNAs after endonuclease, RsaI, digestion. Results: Of 69 tissues examined, 31.9% (22/69) were found to contain HPV DNA. Among 22 HPV‐positive specimens, no HPV types 6, 11, 31 and 33 were detected. On the other hand, HPV 16 and HPV 18 were found in 11 (15.9%) and 10 (14.5%) of HPV‐positive specimens, respectively. One specimen (1.5%) was found to contain both HPV 16 and 18 DNAs. Conclusions: Our findings support that HPV 18, along with HPV 16, may play a certain role in the adenocarcinoma pathogenesis of the uterine cervix.
Consistent improvement with eculizumab across muscle groups in myasthenia gravis
Authors: Mantegazza Renato , O'Brien Fanny L. , Yountz Marcus , Howard James F. ,   for the REGAIN study group
Published: July 2020

Objective

To assess whether eculizumab, a terminal complement inhibitor, improves patient‐ and physician‐reported outcomes (evaluated using the myasthenia gravis activities of daily living profile and the quantitative myasthenia gravis scale, respectively) in patients with refractory anti‐acetylcholine receptor antibody‐positive generalized myasthenia gravis across four domains, representing ocular, bulbar, respiratory, and limb/gross motor muscle groups.

Methods

Patients with refractory anti‐acetylcholine receptor antibody‐positive generalized myasthenia gravis were randomized 1:1 to receive either placebo or eculizumab during the REGAIN study (NCT01997229). Patients who completed REGAIN were eligible to continue into the open‐label extension trial (NCT02301624) for up to 4 years. The four domain scores of each of the myasthenia gravis activities of daily living profile and the quantitative myasthenia gravis scale recorded throughout REGAIN and through 130 weeks of the open‐label extension were analyzed.

Results

Of the 125 patients who participated in REGAIN, 117 enrolled in the open‐label extension; 61 had received placebo and 56 had received eculizumab during REGAIN. Patients experienced rapid improvements in total scores and all four domain scores of both the myasthenia gravis activities of daily living profile and the quantitative myasthenia gravis scale with eculizumab treatment. These improvements were sustained through 130 weeks of the open‐label extension.

Interpretation

Eculizumab treatment elicits rapid and sustained improvements in muscle strength across ocular, bulbar, respiratory, and limb/gross motor muscle groups and in associated daily activities in patients with refractory anti‐acetylcholine receptor antibody‐positive generalized myasthenia gravis.
Depressive Symptoms and the Arthritis–Employment Interface: A Population‐Level Study
Authors: Jetha Arif , Theis Kristina A. , Boring Michael A. , Murphy Louise B. , Guglielmo Dana
Published: July 2020

Objective

To examine the relationship between depressive symptoms, arthritis, and employment, and to determine whether this relationship differs across young, middle‐age, and older working‐age adults with arthritis.

Methods

Data from the US National Health Interview Survey from 2013–2017 were analyzed. Analyses were restricted to adults with doctor‐diagnosed arthritis of working age (ages 18–64 years) with complete data on depressive symptoms (n = 11,380). Covariates were sociodemographic information, health, and health system utilization variables. Employment prevalence was compared by self‐reported depressive symptoms. We estimated percentages, as well as univariable and multivariable logistic regression models, to examine the relationship between depression and employment among young adults (ages 18–34 years), middle‐age adults (ages 35–54 years), and older adults (ages 55–64 years).

Results

Among all working‐age US adults with arthritis, the prevalence of depressive symptoms was 13%. Those reporting depressive symptoms had a higher prevalence of fair/worse health (60%) and arthritis‐attributable activity limitations (70%) compared to those not reporting depression (23% and 39%, respectively). Respondents with depressive symptoms reported significantly lower employment prevalence (30%) when compared to those not reporting depressive symptoms (66%) and lower multivariable‐adjusted association with employment (prevalence ratio 0.88 [95% confidence interval (95% CI) 0.83–0.93]). Middle‐age adults reporting depression were significantly less likely to be employed compared to their counterparts without depression (prevalence ratio 0.83 [95% CI 0.77–0.90]); similar but borderline statistically significant relationships were observed for both young adults (prevalence ratio 0.86 [95% CI 0.74–0.99]) and older adults (prevalence ratio 0.94 [95% CI 0.86–1.03]).

Conclusion

For adults with arthritis, depressive symptoms are associated with not participating in employment. Strategies to reduce arthritis‐related work disability may be more effective if they simultaneously address mental health.
Get a Grip on Factors Related to Grip Strength in Persons With Hand Osteoarthritis: Results From an Observational Cohort Study
Authors: Haugen Ida K. , Aaserud Janni , Kvien Tore K.
Published: July 2020

Objective

To compare levels of grip strength in individuals with hand osteoarthritis (OA) with normative values, and to examine how hand OA severity and other biopsychosocial factors are associated with grip strength.

Methods

Levels of grip strength across age groups were compared with normative values from the general population in sex‐stratified analyses using 2‐sample t‐tests. Associations between radiographic hand OA severity (Kellgren/Lawrence sum score) in different joint groups and grip strength of the same hand were examined in 300 individuals from the Nor‐Hand study using linear regression. Analyses were repeated using markers of pain, demographic factors, comorbidities, and psychological and social factors as independent variables. We adjusted for age, sex, and body mass index.

Results

Individuals with hand OA had lower grip strength than the general population, especially in individuals age <60 years. In thumb base joints, increasing radiographic severity (range 0–8) and the presence of pain were associated with lower grip strength (β = –0.83 [95% confidence interval (95% CI) –1.12, –0.53] and β = –2.15 [95% CI –3.15, –1.16], respectively). Negative associations with grip strength were also found for women, low education, higher comorbidity index, and higher resting heart rate.

Conclusion

Individuals with hand OA have lower grip strength than the general population. Our results support the idea that studies on thumb base OA should include grip strength as an outcome measure. However, other biopsychosocial factors should also be considered when the grip strength is being interpreted, because other factors such as sex, socioeconomic factors, physical fitness, and comorbidities are negatively associated with grip strength.
Exosomes in Tumor Immunotherapy: Mediator, Drug Carrier, and Prognostic Biomarker
Authors: Wan Zhuo , Dong Yan , Wei Mengying , Gao Xiaotong , Yang Guodong , Zhang Jian , Liu Li
Published: July 2020

Exosomes, which are small lipid bilayer vesicles that can be released by multiple cell types, mediate communication between cells by transporting nucleic acids, proteins, and other bioactive molecules. Pioneering studies have revealed that exosomes can exert multiple functions in shaping tumor immune responses in the crosstalk between tumor cells and surrounding immune cells. Emerging studies have also demonstrated the powerful function of engineered exosomes in cancer immunotherapy. Here, the recent progress in this field and focus on exosomes as mediators, drug carriers, and prognostic biomarkers in tumor immunotherapy is summarized. This review not only summarizes the progress of this field, but also provides insights and perspectives on exosome‐based strategies in cancer immunotherapy.
Template‐Directed Growth of Hierarchical MOF Hybrid Arrays for Tactile Sensor
Authors: Zhou Kui , Zhang Chen , Xiong Ziyu , Chen Hong‐Ye , Li Teng , Ding Guanglong , Yang Baidong , Liao Qiufan , Zhou Ye , Han Su‐Ting
Published: July 2020

Recently, conductive metal−organic frameworks (MOFs) as the active material have provided broad prospects for electronic device application. The positioning technologies for MOFs enable the fabrication of novel microstructures, which can modulate the morphology of the material and tune the properties for the targeted application. Herein, a template‐method is used to synthesize the hierarchical structure of MOF hybrid array (MHA) on copper mesh (MHA@Mesh) for flexible sensor. Finite element method (FEM) results indicate that the 3D hierarchical MHA@Mesh can mimic the micro/nanoscale structure of human skin, which enables an interlocking contact. MHA@Mesh‐based flexible sensor presents rapid response rate (<1 ms) and high sensitivity (up to 307 kPa−1) which is 20 times higher than that of MHA@Foil‐based sensor (15 kPa−1). The flexible pressure device could be applied to monitor the finger motion and human pulses. Moreover, the music recognition can be performed by integrating the MOFs hardware sensors with machine learning algorithms. Overall, this design concept of 3D hierarchical microarray structures demonstrates potential in the fields of wearable technologies and human–machine interfaces.
One‐Step Preparation of Biocompatible Gold Nanoplates with Controlled Thickness and Adjustable Optical Properties for Plasmon‐Based Applications
Authors: Ye Sunjie , Connell Simon D. , McLaughlan James R. , Roach Lucien , Aslam Zabeada , Chankhunthod Navadecho , Brown Andy P. , Brydson Rik , Bushby Richard J. , Critchley Kevin , Coletta P. Louise , Markham Alexander F. , Evans Stephen D.
Published: July 2020

The ability to synthesize plasmonic nanomaterials with well‐defined structures and tailorable size is crucial for exploring their potential applications. Gold nanoplates (AuNPLs) exhibit appealing structural and optical properties, yet their applications are limited by difficulties in thickness control. Other challenges include a narrow range of tunability in size and surface plasmon resonance, combined with a synthesis conventionally involving cytotoxic cetyltrimethylammonium (CTA) halide surfactant. Here, a one‐step, high‐yield synthesis of single‐crystalline AuNPLs is developed, based on the combined use of two structure‐directing agents, methyl orange and FeBr3, which undergo preferential adsorption onto different crystalline facets of gold. The obtained AuNPLs feature high shape homogeneity that enables mesoscopic self‐assembly, broad‐range tunability of dimensions (controlled thickness from ≈7 to ≈20 nm, accompanied by modulation of the edge length from ≈150 nm to ≈2 µm) and plasmonic properties. These merits, coupled with a preparation free of CTA‐halide surfactants, have facilitated the exploration of various uses, especially in bio‐related areas. For example, they are demonstrated as biocompatible photothermal agents for cell ablation in NIR I and NIR II windows. This work paves the way to the innovative fabrication of anisotropic plasmonic nanomaterials with desired attributes for wide‐ranging practical applications.
Full‐State Synthesis of Electromagnetic Fields using High Efficiency Phase‐Only Metasurfaces
Authors: Wu Jun Wei , Wang Zheng Xing , Fang Zu Qi , Liang Jing Cheng , Fu Xiaojian , Liu Jun Feng , Wu Hao Tian , Bao Di , Miao Long , Zhou Xiao Yang , Cheng Qiang , Cui Tie Jun
Published: July 2020

A metasurface is a thin array of subwavelength elements with designable scattering responses, and metasurface holography is a powerful tool for imaging and field control. The existing metasurface holograms are classified into two types: one is based on phase‐only metasurfaces (including the recently presented vectorial metasurface holography), which has high power efficiency but cannot control the phases of generated fields; while the other is based on phase‐amplitude‐modulated metasurfaces, which can control both field amplitudes and phases in the region of interest (ROI) but has very low efficiency. Here, for the first time, it is proposed to synthesize the field amplitudes and phases in ROI simultaneously and independently by using high‐efficiency phase‐only metasurfaces. All points in ROI may have independent values of field amplitudes and phases, and the requirements for X and Y components may be different in achieving spatially varied polarization states. To this end, an efficient design method based on equivalent electromagnetic model and gradient‐based nonlinear optimization is proposed. Full‐wave simulations and experimental results demonstrate that the phase‐only metasurface designed by the method has 10 times higher efficiency than the phase‐amplitude‐modulated metasurface. This work opens a way to realize more complicated and high‐efficiency metasurface holography.