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PubMed2002

Sequential muscle activity and its functional role in the upper extremity and trunk during overarm throwing.

The proximal-to-distal segmental sequence has been identified in many sports activities, including baseball pitching and ball kicking. However, proximal-to-distal sequential muscle activity has not been identified. The aims of this study were to establish whether sequential muscle activity does occur and, if it does, to determine its functional role. We recorded surface electromyograms (EMGs) for 17 muscles from the upper extremity and abdomen during overarm throwing and detected the onset and peak times as indices of muscle activity. The following electromyographic properties were commonly identified in the participants. First, sequential muscle activity was observed from the scapular protractors to the shoulder horizontal flexors and from the shoulder horizontal flexors to the elbow extensor, but not from the elbow extensor to the wrist flexor or forearm pronator. Secondly, the external oblique contralateral to the throwing arm became activated before the ipsilateral external oblique. This sequence is considered to be very effective for the generation of high force and energy in the trunk. Thirdly, the ipsilateral external oblique began its activity almost at foot strike. Finally, the main activity of the rectus abdominis appeared just before the point of release.

Abdominal Muscles↗

PubMed2002

Guanine of the third strand of C.G*G triplex serves as an effective hole trap.

We have examined the structural and electronic effects of the one-electron oxidation of the C.GG triplex, where G is located in a quite different environment from the G of duplex DNA. Upon photoirradiation of an external photosensitizer (riboflavin) with the C.GG triplex, oxidative DNA cleavage occurred exclusively at guanine repeat sequences in the third strand of triple helix DNA. Hole transport through the C.GG triplex also occurred, resulting in selective cleavage at G in the third strand. Thus, the hole generated in the duplex can migrate to GGG in the third strand and is trapped exclusively at Gs in the third strand. These experimental results, together with molecular orbital calculations, suggest that the origin of the selective strand cleavage can be explained as follows: (i) guanine repeat sequences in the third strand are more easily oxidized than in duplex DNA and (ii) in their radical cation states, G of the third strand rapidly deprotonates and reacts with oxygen and/or water, leading to strand cleavage. These results indicate that the oxidative damage preferentially occurred at Gs of the third strand owing to thermodynamic and kinetic features of the one-electron oxidation of the C.GG triplex.

Base Pairing↗

PubMed1994

Life cycles and host-parasite relationships of Microsporidia in culicine mosquitoes.

Heterosporous (polymorphic) microsporidia in mosquitoes are characterized by intricate life cycles involving multiple spore types responsible for horizontal (per os) and vertical (transovarial) transmission. They affect two generations of the mosquito and some involve an obligate intermediate host. Heterosporous microsporidia are generally very host and tissue specific with complex developmental sequences comprised of unique stages and events. Full details on the intricate relationships between heterosporous microsporidia and their mosquito hosts have only recently been elucidated. Edhazardia aedis (Kudo, 1930) and Culicospora magna (Kudo, 1920) have developmental sequences in larvae that involve gametogony followed by plasmogamy and nuclear association to form diplokarya. These diplokaryotic stages then undergo karyogamy and form binucleate spores responsible for transovarial transmission. In the filial generation, haplosis occurs as a result of nuclear dissociation to produce uninucleate spores infectious to larval mosquitoes. Amblyospora californica (Kellen et Lipa, 1960) has similar sequences except that haplosis is by meiosis to produce spores infectious for a copepod intermediate host. A third spore type is formed in the intermediate host responsible for infection in a new generation of the mosquito host.

Animals↗

PubMed1996

Lambda clone B22 contains a 7676 bp genomic fragment of Saccharomyces cerevisiae chromosome VII spanning the VAM7-SPM2 intergenic region and containing three novel transcribed open reading frames.

A genomic clone of 7676 bp designated B22 from Saccharomyces cerevisiae has been sequenced. The 5' end matches the previously described gene, VAM7, and the 3' end matches the previously described gene, SPM2, both of which have been assigned to the left arm of chromosome VII. The intergenic region contains three transcribed open reading frames (ORFs). The first is related to an uncharacterized ORF of Bacillus subtilis and more weakly to MesJ in Escherichia coli; this is found as a single transcript of 1.1 kb by Northern blotting. The second ORF encodes a small ras-like GTPase of 222 residues with strong homology to yeast Ypt8p and to mammalian Rab11; this is found as a single transcript of 1.1 kb by Northern blotting. The third ORF generates a transcript of 1.6 kb and encodes a protein of 382 residues including a perfect match to the consensus sequence of a C2H2 zinc finger domain; it shares a strong homology with yeast Mig1p and Cre-A from Aspergillus, Emericella and E. coli. This ORF also has a striking similarity to a putative 43 kDa zinc finger protein encoded by an ORF (YEL8) immediately downstream of YPT8, raising the possibility that a region between VAM7 and SPM2 on chromosome VII arose as a duplication of the YPT8-YEL8 region of chromosome V, followed by a translocation.

Amino Acid Sequence↗

PubMed1999

Characterisation of the helicostatin peptide precursor gene from Helicoverpa armigera (Lepidoptera: Noctuidae).

The gene encoding the helicostatin peptide family was isolated from a Helicoverpa armigera genomic DNA library. The deduced precursor sequence allowed unambiguous identification of all helicostatin peptides and verified the sequences of eight peptides previously isolated. The gene consists of at least three exons and encodes a precursor of 225 amino acids that contains three blocks of tandemly arranged helicostatin peptides including seven copies of the C-terminal sequence -YXFGL followed by a single Gly residue for carboxylamidation. Complete endoproteolytic processing at all possible dibasic cleavage sites would generate the seven helicostatin octapeptides previously purified from larval extracts. If processing was not complete at the third pair of basic amino acids the octadecapeptide (helicostatin IIa) would also be released. Two novel putative helicostatin peptide sequences were identified; YSKFNFGL and ERDMHRFSFGL, both of which had the C-terminal pentapeptide -FXFGL in place of the more usual -YXFGL sequence. Comparison of the helicostatin precursor with that of the cockroaches, locust and flies revealed variation in size, sequence and organisation of the 'allatostatin' precursors across different insect orders. In situ hybridisation histochemistry established that helicostatins are expressed in neurones of the central nervous system and endocrine cells of the midgut, indicating that the helicostatins are true brain-gut peptides. Northern blot analysis identified a single transcript of 1.6 kb in mRNA from whole larvae, isolated central nervous system and gut tissue.

Amino Acid Sequence↗

PubMed2001

Real time distributed processing of multiple associated pulse pattern sequences.

A Real Time Distributed Associative Memory Artificial Neural Network (RTANN) is described. This network associates groups of pulse pattern sequences. The subsequent reoccurrence of some sequences will cause the remainder to be regenerated. Training is carried out in real time simply by feeding pattern sequences directly into the network. The connections between units incorporate a wide range of transmission delays. During training the network enhances connection weights on units where coincidences occur between input and delayed pulses. Pattern regeneration utilises the reoccurrence of coincidences between delayed pulses. The simulation of an RTANN is presented. Continuous dual pattern sequences from notional sensors monitoring the shape and colour of an object were associated directly with a third dual pattern sequence having the form 'These objects look colour'. After training the network was able to correctly generate sentences describing combinations of object and colour not encountered during training.

Artificial Intelligence↗

PubMed2002

Transferable plasmid mediating resistance to multiple antimicrobial agents in Klebsiella pneumoniae isolates in Greece.

OBJECTIVE: To investigate the underlying resistance mechanisms in 10 Klebsiella pneumoniae isolates. METHODS: Ten K. pneumoniae strains according to distinct bacteriocin typing and REP-PCR, were examined for their plasmid content, their ability to transfer their resistance to aminoglycosides and third-generation cephalosporins, and their production of aminoglycoside-modifying enzymes and beta-lactamases. RESULTS: Transfer of resistance to the above-mentioned antibiotics as well as to co-trimoxazole and tetracycline in Escherichia coli strain RC 85 at a frequency of 5-106 was achieved for all strains by conjugation. Similar strains harbor a self-transferable multiresistant plasmid (80 kb) with similar EcoRI and HindIII restriction patterns. This plasmid encodes an extended-spectrum beta-lactamase which confers high-level resistance to third-generation cephalosporins and aztreonam. It produces SHV-5 beta-lactamase, as demonstrated by isoelectric focusing and DNA sequencing. Aminoglycoside resistance was co-transferred, and AAC(6')-I, mediating resistance to gentamicin, tobramycin, netilmicin and amikacin, and AAC(3)-I, mediating resistance to gentamicin and sisomycin, were encoded in all isolates and their transconjugants, while APH(3')-I, mediating resistance to kanamycin and neomycin, was encoded in seven strains. CONCLUSIONS: It appears that a multiresistant transferable plasmid encoding the SHV-5 beta-lactamase, causing unusually high resistance to ceftazidime and aztreonam, and the combination AAC(6')-I + AAC(3)-I of acetylating enzymes causing, also resistance to all clinically available aminoglycosides, is established in K. pneumoniae in Greece.

Anti-Bacterial Agents↗

PubMed1993

Assessment of disparate structural features in three models of the hepatitis delta virus ribozyme.

Three models for the secondary structure of the hepatitis delta virus (HDV) antigenomic self-cleaving RNA element were tested by site-directed mutagenesis. Two models in which bases 5' to the cleavage site are paired with sequence at the 3' end of the element were both inconsistent with the data from the mutagenesis. Specifically, mutations in the 3' sequence which decrease self-cleavage activity could not be compensated by base changes in the 5' sequence as predicted by these models. The evidence was consistent with a third model in which the 3' end pairs with a portion of a loop within the ribozyme sequence to generate a pseudoknot structure. This same pairing was also required to generate higher rates of cleavage in trans with a 15-mer ribozyme, thus ruling out a proposed hammerhead-like 'axehead' model for the HDV ribozyme.

Base Sequence↗

PubMed1996

Favored use of immunoglobulin V(H)4 Genes in AIDS-associated B-cell lymphoma.

We examined the lg heavy chain variable region genes (Ig V(H) genes) expressed in biopsy specimens of 10 patients with acquired immunodeficiency syndrome (AIDS)-associated lymphoma. Eight expressed Ig V(H) genes of the V(H)4 group, indicating a bias toward expression of Ig V(H) genes of this subgroup. Sequence analyses of Ig V(H) genes isolated from any one lymphoma did not reveal evidence for intraclonal diversity. However, some lymphomas express Ig V(H) genes that apparently have undergone somatic diversification and selection. In addition, we found that the sequence encoding each examined third complementarity determining region most likely resulted from D-D fusion, a process that ordinarily contributes to the generation of a relatively small proportion of the Ig heavy chain genes expressed by normal adult B cells. The noted restriction in the use of Ig V(H) genes by AIDS-associated B-cell lymphomas suggests that antigenic stimulation contributes to lymphomagenesis in patients with AIDS.

Adult↗

PubMedDate not supplied

Plasmid-mediated resistance to third-generation cephalosporins caused by point mutations in TEM-type penicillinase genes.

Infections due to strains of Klebsiella pneumoniae, Escherichia coli, and Citrobacter freundii resistant to third-generation cephalosporins have been observed recently in France and the Federal Republic of Germany. This resistance phenotype is due to the production of new plasmid-mediated, broad-substrate-range beta-lactamases designated TEM-3 to TEM-7. DNA-DNA hybridization analysis with a probe specific for TEM-1 indicated that the corresponding genes blaT-3 to blaT-7 were variants of the structural genes for TEM-type beta-lactamases. In the present studies, a 2.5-kilobase BamHI plasmid DNA fragment encoding TEM-3 was cloned in E. coli, and the entire nucleotide sequence of blaT-3 was determined. The deduced amino acid sequence of TEM-3 differed in two positions from that of the TEM-2 enzyme: lysine (TEM-3) was substituted for glutamic acid (TEM-2) at residue 104 and serine (TEM-3) for glycine (TEM-2) at residue 238 in the numbering system of Ambler. Spontaneous mutants of TEM penicillinases with increased activity against third-generation cephalosporins were obtained in vitro by selection on cefotaxime or ceftazidime. It therefore appears that mutations in TEM-type beta-lactamases contribute to resistance to new-generation cephalosporins.

Amino Acid Sequence↗

PubMed2025

Exome sequencing identifies a homozygous splice site variant in RP1 as the underlying cause of autosomal recessive retinitis pigmentosa in a Pakistani family.

BACKGROUND: Mutations in RP1 gene are the third leading cause of inherited retinal dystrophies (IRDs) in Pakistani families. PATIENTS: A two-generation consanguineous Pakistani family underwent both clinical and genetic analyses. Clinical examinations included visual acuity test, visual field, fundoscopy, and ocular coherence tomography (OCT). Whole exome sequencing (WES) was performed on the proband's DNA, and Sanger sequencing was performed to validate the WES findings. Splicing prediction tools such as Human Splicing Finder (HSF), NNSplice predictor, SpliceAI, MaxENTScan, and SpliceRover were used. RESULTS: A nuclear family of seven children, comprising five affected individuals (four males and one female) and two healthy siblings, was recruited from northwestern Pakistan. The proband was a 49-years old male who was presented with complaints of decreased visual acuity and night blindness since early childhood. Upon clinical evaluation, the proband appeared to have severely reduced visual acuity of hand movement (HM), bilateral visual field constriction, a waxy pale disc with vascular attenuation, pigmentary bone spicules at the periphery associated with chorioretinal degeneration, diffuse macular atrophy, and horizontal nystagmus in both of his eyes. Exome sequencing (ES) in the proband identified a homozygous splice site variant (NM_006269.2: c.615 + 1G > A) in RP1 gene. In-silico analysis, genotype-phenotype co-segregation study, and literature survey strongly supported the causality of the detected variant. CONCLUSIONS: We report a previously known pathogenic splice site variant of RP1 as the underlying cause of early-onset autosomal recessive retinitis pigmentosa (arRP) in a Pakistani family. We contemplate that the detected allele might constitute a mutational hotspot in RP1.

Humans↗

PubMed1995

The three C-terminal residues of human respiratory syncytial virus G glycoprotein (Long strain) are essential for integrity of multiple epitopes distinguishable by antiidiotypic antibodies.

Recently isolated escape mutants of human respiratory syncytial virus (HRSV) are described. The mutants were selected after serial passage of the Long strain in the presence of monoclonal antibodies directed against the attachment (G) glycoprotein. The genetic changes associated to the mutant phenotype were nucleotide substitutions leading to either amino acid replacements or new stop codons that shorten the G polypeptide by one amino acid. Sequence changes within the three C-terminal residues of the G molecule abolished multiple epitopes, some of them being distinguished only by virus-binding inhibition of the corresponding antibodies with a panel of antiidiotypic antisera. These results extend previous studies that demonstrated the extreme capacity of HRSV to accommodate multiple sequence changes within the antigenically relevant G protein C-terminal third. These results are discussed in terms of both the antigenic structure of the G molecule and the generation of new antigenic variants that mimic natural variants of HRSV.

Amino Acid Sequence↗

PubMed1994

An estimate of the number of serine protease genes expressed in sheep blowfly larvae (Lucilia cuprina).

A large and diverse family of serine protease genes was identified in first-instar larval cDNA of the sheep blowfly (Lucilia cuprina). This complex repertoire of genes was identified via a PCR approach using highly degenerate primers based on structurally conserved regions which surround the active site His and Ser residues found in all serine proteases. PCR products from entire first-instar larval cDNA, or from third-instar larval salivary glands or cardia, generated using a microscale RT-PCR method, were cloned into a plasmid vector. Comparison of the restriction fragment patterns of PCR products generated from the three different sources suggests a highly diverse tissue-specific pattern of serine protease expression in this organism. Detailed analysis of the restriction fragment patterns of sixty-nine randomly selected clones from entire first-instar larvae revealed forty-nine different classes of PCR product. Maximum likelihood analysis of these data indicate that between 125 and 220 different serine protease genes are expressed in first-instar larvae of L. cuprina. DNA sequence analysis of ten randomly-selected clones, derived from the three tissue sources, indicated that all ten encoded serine protease gene fragments. A frequently occurring PCR product, generated from both first-instar total cDNA and third-instar cardia cDNA, showed 73% amino acid identity to a digestive protease expressed in Drosophila melanogaster larval gut cells.

Amino Acid Sequence↗

PubMed1994

NMR assignments and secondary structure of the retinoid X receptor alpha DNA-binding domain. Evidence for the novel C-terminal helix.

The retinoid X receptor (RXR) is a member of the nuclear hormone receptor superfamily and has recently been shown to function in a variety of hormonal signaling pathways by virtue of its ability to heterodimerize with other nuclear hormone receptors. Here we describe resonance assignments, the secondary structural elements and the global folding pattern of the DNA-binding domain (residues 130-223) of human RXR alpha, as determined by multidimensional nuclear magnetic resonance spectroscopy. Its overall structure is similar to those reported for the glucocorticoid, estrogen, and retinoic acid receptors, in that the two zinc fingers of RXR fold to form a single structural domain containing two helices, which are located at the carboxy terminal of the two zinc fingers. There is also a short antiparallel beta-sheet formed between two residues in the amino-terminal base of the first finger and two residues in the carboxy terminal of that same finger just before the first helix. However, in contrast to the other nuclear hormone receptor DNA-binding domains, the RXR domain contains a third helix immediately after the conserved Gly-Met sequence that signals the termination of the second helix. The second and third helices lie orthogonal to and wrap around the first helix, generating an extended hydrophobic core. Since helices two and three are separated by only two residues, the backbone flexibility afforded by the presence of the conserved glycine residue between them may be crucial for the proper positioning of the third helix relative to the first helix. A 12-amino-acid region termed the 'T-box', which includes this third helix, was recently shown to be required for homodimeric binding of RXR to its cognate response element [Wilson, T. E., Paulsen, R. E., Padgett, K. A. & Milbrandt, J. (1992) Science 256, 107-110].

Amino Acid Sequence↗

PubMed1990

Multiecho multimoment refocussing of motion in magnetic resonance imaging: MEM-MO-RE.

Gradient moment nulling techniques for refocussing of spin dephasing resulting from movement during application of magnetic resonance imaging gradients have gained widespread application. These techniques offer advantages over conventional imaging gradients by reducing motion artifacts due to intraview motion, and by recovering signal lost from spin dephasing. This paper presents a simple technique for designing multiecho imaging gradient waveforms that refocus dephasing from the interaction of imaging gradients and multiple derivatives of position. Multiple moments will be compensated at each echo. The method described relies on the fact that the calculation of time moments for nulled moment gradient waveforms is independent of the time origin chosen. Therefore, waveforms used to generate the second echo image for multiple echo sequences with echo times given by TEn = TE1 + (n - 1) * (TE2 - TE1) may also be used for generation of the third and additional echo images. All echoes will refocus the same derivatives of position. Multiecho, multimoment refocussing (MEM-MO-RE) images through the liver in a patient with ampullary adenocarcinoma metastatic to the liver demonstrate the application of the method in clinical scanning.

Adenocarcinoma↗

PubMed1987

Analysis of cDNA clones that code for the transmembrane forms of the mouse neural cell adhesion molecule (NCAM) and are generated by alternative RNA splicing.

The neural cell adhesion molecule (NCAM) exists in at least three different isoforms. In the mouse, NCAM proteins with apparent Mr's of 180,000, 140,000 and 120,000 have been distinguished. These are encoded by 4 to 5 different transcripts. Here we report the full amino acid sequence of an isoform which most likely represents NCAM-140. The N-terminal extracellular portion of the 829-residue polypeptide appears to be identical to all three NCAM proteins. The Mr of 91,276 is considerably smaller than the estimate based on SDS-gel electrophoresis. The 147 C-terminal residues are distinct from NCAM-120 and contain the putative transmembrane and cytoplasmic domains. The transcript encoding NCAM-140 contains almost 3.2 kb non-coding sequence with a canonical polyadenylation signal. While the 5' sequences of NCAM-140 hybridize with all NCAM mRNAs, the 3' probes recognize only the two larger transcripts of 7.4 and 6.7 kb. From S1 nuclease protection analyses and hybridization studies of several NCAM cDNA clones with genomic NCAM sequences one can conclude that the different NCAM transcripts are generated by alternative splicing. In addition to the two alternative splice sites in the sequence encoding the extracellular domains, a third one can be predicted approximately 320 nt downstream of the start of the NCAM-140-specific sequence portion. This finding is in agreement with the existence of an extra exon in the chicken NCAM-180. Comparison between mouse and chicken NCAM amino acid sequences revealed the highest homology in the second and fifth Ig-like domains and in the cytoplasmic parts suggesting that these regions serve highly conserved functions.

Amino Acid Sequence↗

PubMed2001

Identification by 16S ribosomal RNA gene sequencing of an Enterobacteriaceae species with ambiguous biochemical profile from a renal transplant recipient.

Traditional ways of identification of bacteria by phenotypic characteristics cannot be used for non-cultivable organisms and organisms with unusual biochemical profiles. In this study, an Enterobacteriaceae was isolated in pure growth from the mid-stream urine of a 67-year old renal transplant recipient with urinary tract infection. Conventional biochemical tests did not reveal a pattern resembling any known member of the Enterobacteriaceae family. The Vitek system (GNI+) showed that it was 18% Leclercia adecarboxylata and 55% Klebsiella ozaenae; whereas the API system (20E) showed that it was 99.8% Rahnella aquatilis. 16S ribosomal RNA gene sequencing showed that there was 7 base differences between the isolate and Enterobacter cloacae, 18 base differences between the isolate and Enterobacter asburiae, 17 base differences between the isolate and Enterobacter cancerogenus, 35 base differences between the isolate and K. ozaenae, 27 base differences between the isolate and L. adecarboxylata, and 72 base differences between the isolate and R. aquatilis, indicating that the isolate most closely resembled a strain of E. cloacae. Identification of the organism in this study is important, as the choice of antibiotics would be radically different. In this case, cephalosporins should be avoided regardless of in-vitro susceptibility as cephalosporins are well-known to select for AmpC derepressed mutants in Enterobacter, and previous administration of third-generation cephalosporins is more likely to be associated with multidrug resistant Enterobacter isolates than is administration of antibiotics that do not include a third-generation cephalosporin.

Aged↗

PubMed1997

Isolation of DNA from the centromere of human chromosome 7 by microdissection.

Centromeres remain the least characterized regions of human chromosomes because they have a very high content of repetitive DNA. Here, we describe a microdissection library from the centromeric region of human chromosome 7 and its use for generating sequence tagged sites (STSs). The library contains about 1500 clones with an average insert size of 150 bp and only about 15% of the clones harbour repetitive human DNA. Seven clones hybridizing to alphoid DNA were found to correspond to a fragment of the D7Z2 alphoid array on chromosome 7, thus confirming the origin of the library. A number of clones not containing known repetitive DNA were used to generate STSs that identified yeast artificial chromosomes (YACs) and in turn allowed the STSs to be placed on the physical map. One STS is located between the two Genethon genetic markers closest to the centromere on the q side. Another STS was located 3-4cM away in 7q11.2, while a third identified YACs containing both low-copy and alphoid sequences that are not yet mapped but are clearly centromeric. The library therefore comprises a collection of sequences from the centromeric region of chromosome 7 that can be used to generate STSs and to map the entire centromeric region.

Amniotic Fluid↗