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PubMed2005

Involvement of a Che-like signal transduction cascade in regulating cyst cell development in Rhodospirillum centenum.

Homologues of the E. coli chemotaxis (Che) signal transduction pathway are present in nearly all motile bacteria. Although E. coli contains only one Che cascade, many other bacteria are known to possess multiple sets of che genes. The role of multiple che-like gene clusters could potentially code for parallel Che-like signal transduction pathways that have distinctly different input and output functions. In this study, we describe a che-like gene cluster in Rhodospirillum centenum that controls a developmental cycle. In-frame deletion mutants of homologues of CheW (DeltacheW(3a)and DeltacheW(3b)), CheR (DeltacheR(3)), CheA (DeltacheA(3)) and a methyl-accepting chemotaxis protein (Deltamcp(3)) are defective in starvation-induced formation of heat and desiccation resistant cyst cells. In contrast, mutants of homologues of CheY (DeltacheY(3)), CheB (DeltacheB(3)), and a second input kinase designated as CheS (DeltacheS(3)) result in cells that are derepressed in the formation of cysts. A model of signal transduction is presented in which there are three distinct Che-like signal transduction cascades; one that is involved in chemotaxis, one that is involved in flagella biosynthesis and the third that is involved in cyst development.

Bacterial Proteins↗
PubMed2005

Cross-cultural comparison of the neurobehavioral characteristics of Chinese and Japanese neonates.

BACKGROUND: Similarities and differences in the neurobehavioral repertoire of neonates from different cultures have been noted using the Brazelton Neonatal Behavioral Assessment Scale (NBAS). By identifying the behavioral attributes of newborns that are seen more universally versus those that are culture-specific, comparative studies increase understanding of the roles of cultural factors in shaping the behavioral trajectory of infants. This study compared the neurobehavioral characteristics of neonates in Chengdu, China and Nagasaki, Japan. METHODS: The Brazelton NBAS was administered within the first week of life to 40 Chinese and 62 Japanese healthy, full-term neonates in Chengdu and Nagasaki. RESULTS: The two groups differed significantly in birthweight, gender, age at time of exam, mode of delivery, and gestational age. When these variables, in addition to group status (Chinese or Japanese), were entered into multiple linear analyses with NBAS cluster scores as dependent variables, group status independently predicted Range of State and Habituation scores. The group status did not predict Orientation, Motor, Regulation of States, Autonomic Stability, and Abnormal Reflexes cluster scores. CONCLUSION: These results suggest that Japanese newborns habituated more readily to stimuli, and were less irritable than newborns in the Chinese sample. The infants in the two groups shared many similar neurobehavioral characteristics as well. The implications of these similarities and differences were discussed.

China↗
PubMed2006

Clonal adaptive radiation in a constant environment.

The evolution of new combinations of bacterial properties contributes to biodiversity and the emergence of new diseases. We investigated the capacity for bacterial divergence with a chemostat culture of Escherichia coli. A clonal population radiated into more than five phenotypic clusters within 26 days, with multiple variations in global regulation, metabolic strategies, surface properties, and nutrient permeability pathways. Most isolates belonged to a single ecotype, and neither periodic selection events nor ecological competition for a single niche prevented an adaptive radiation with a single resource. The multidirectional exploration of fitness space is an underestimated ingredient to bacterial success even in unstructured environments.

Adaptation, Physiological↗
PubMed1998

Phosphorylation and activation of 13S condensin by Cdc2 in vitro.

13S condensin is a multisubunit protein complex essential for mitotic chromosome condensation in Xenopus egg extracts. Purified 13S condensin introduces positive supercoils into DNA in the presence of topoisomerase I and adenosine triphosphate in vitro. The supercoiling activity of 13Scondensin was regulated by mitosis-specific phosphorylation. Immunodepletion, in vitro phosphorylation, and peptide-mapping experiments indicated that Cdc2 is likely to be the kinase that phosphorylates and activates 13S condensin. Multiple Cdc2 phosphorylation sites are clustered in the carboxyl-terminal domain of the XCAP-D2 (Xenopus chromosome-associated polypeptide D2) subunit. These results suggest that phosphorylation of 13Scondensin by Cdc2 may trigger mitotic chromosome condensation in vitro.

Adenosine Triphosphatases↗
PubMed2000

Efficient initiation of HCV RNA replication in cell culture.

Hepatitis C virus (HCV) infection is a global health problem affecting an estimated 170 million individuals worldwide. We report the identification of multiple independent adaptive mutations that cluster in the HCV nonstructural protein NS5A and confer increased replicative ability in vitro. Among these adaptive mutations were a single amino acid substitution that allowed HCV RNA replication in 10% of transfected hepatoma cells and a deletion of 47 amino acids encompassing the interferon (IFN) sensitivity determining region (ISDR). Independent of the ISDR, IFN-alpha rapidly inhibited HCV RNA replication in vitro. This work establishes a robust, cell-based system for genetic and functional analyses of HCV replication.

Amino Acid Substitution↗
PubMed2002

A resistance-nodulation-cell division family xenobiotic efflux pump in an obligate anaerobe, Porphyromonas gingivalis.

Porphyromonas gingivalis, a gram-negative obligate anaerobe, contains two homologs of an Escherichia coli resistance-nodulation-cell division-type multidrug exporter gene, acrB, in putative operons, together with homologs of membrane fusion protein gene acrA and outer membrane channel gene tolC. MIC determination and accumulation assays with mutants with disruptions of one or more genes showed that one cluster, named xepCAB, pumped out multiple agents including rifampin, puromycin, and ethidium bromide.

Anaerobiosis↗
PubMed2006

Clonal dissemination of Escherichia coli O157:H7 subtypes among dairy farms in northeast Ohio.

To ascertain the extent to which indistinguishable strains of Escherichia coli O157:H7 are shared between farms, molecular characterization was performed on E. coli O157:H7 isolates recovered during a longitudinal study of 20 dairy farms in northeast Ohio. Of the 20 dairy farms sampled, 16 were located in a primary area and 4 were located in two other distant geographical areas. A total of 92 E. coli O157:H7 isolates obtained from bovine fecal samples, water trough sediment samples, free-stall bedding, and wild-bird excreta samples were characterized. Fifty genetic subtypes were observed among the isolates using XbaI and BlnI restriction endonucleases. Most restriction endonuclease digestion profiles (REDPs) were spatially and temporally clustered. However, four REDPs from multiple sources were found to be indistinguishable by pulsed-field gel electrophoresis between four pairs of farms. The geographical distance between farms which shared an indistinguishable E. coli O157:H7 REDP ranged from 9 to 50 km, and the on-farm sources sharing indistinguishable REDPs included cattle and wild bird feces and free-stall bedding. Within the study population, E. coli O157:H7 REDP subtypes were disseminated with considerable frequency among farms in close geographic proximity, and nonbovine sources may contribute to the transmission of this organism between farms.

Animal Husbandry↗
PubMed2000

Characterization of a multigene family undergoing high-frequency DNA rearrangements and coding for abundant variable surface proteins in Mycoplasma agalactiae.

A family of abundant surface proteins (Vpmas [variable proteins of Mycoplasma agalactiae]) undergoing phase variation in M. agalactiae has been characterized using monoclonal antibodies and specific polyclonal sera. Two expressed members of 39 kDa (Vpma39) and 34 kDa (Vpma34), which varied in expression between clones of a lineage, shared a common amino-terminal sequence but were immunologically distinct. An amino-terminal oligonucleotide probe identified multiple vpma genes which were clustered within a 14-kb ClaI genomic fragment. Rearrangements were found to have occurred within the vpma locus between clones which correlated with changes in their Vpma phenotype. Two neighboring vpma genes were cloned and sequenced from one M. agalactiae clonal variant expressing Vpma39. The two genes, vpmaX and vpmaY, were orientated divergently and shared highly homologous 5' untranslated regions, 25-amino-acid (aa) lipoprotein leader sequences, and amino-terminal sequences. The vpmaY gene coded for 346 aa and 84% of the open reading frame, comprised of 1.5 units of a large repeat of 186 aa. Although the sequence for an entire second vpmaY repeat was present, it was prematurely terminated by insertion of two nucleotides. The vpmaX gene encoded 221 aa and possessed 102 aa of the 186-aa repeat of vpmaY. Many of the features in common between the vpma genes were also found to be shared by the vsp genes of M. bovis, which also undergo DNA rearrangements concomitant with phenotypic changes. Since M. bovis is the closest phylogenetic relative to M. agalactiae, the vpma and vsp gene families most probably represent homologous systems.

Amino Acid Sequence↗
PubMed2003

Isolation and identification of Triticeae chromosome 1 receptor-like kinase genes (Lrk10) from diploid, tetraploid, and hexaploid species of the genus Avena.

The DNA sequence of an extracellular (EXC) domain of an oat (Avena sativa L.) receptor-like kinase (ALrk10) gene was amplified from 23 accessions of 15 Avena species (6 diploid, 6 tetraploid, and 3 hexaploid). Primers were designed from one partial oat ALrk10 clone that had been used to map the gene in hexaploid oat to linkage groups syntenic to Triticeae chromosome 1 and 3. Cluster (phylogenetic) analyses showed that all of the oat DNA sequences amplified with these primers are orthologous to the wheat and barley sequences that are located on chromosome 1 of the Triticeae species. Triticeae chromosome 3 Lrk10 sequences were not amplified using these primers. Cluster analyses provided evidence for multiple copies at a locus. The analysis divided the ALrk EXC sequences into two groups, one of which included AA and AABB genome species and the other CC, AACC, and CCCC genome species. Both groups of sequences were found in hexaploid AACCDD genome species, but not in all accessions. The C genome group was divided into 3 subgroups: (i) the CC diploids and the perennial autotetraploid, Avena macrostachya (this supports other evidence for the presence of the C in this autotetraploid species); (ii) a sequence from Avena maroccana and Avena murphyi and several sequences from different accessions of A. sativa; and (iii) A. murphyi and sequences from A. sativa and Avena sterilis. This suggests a possible polyphyletic origin for A. sativa from the AACC progenitor tetraploids or an origin from a progenitor of the AACC tetraploids. The sequences of the A genome group were not as clearly divided into subgroups. Although a group of sequences from the accession 'SunII' and a sequence from line Pg3, are clearly different from the others, the A genome diploid sequences were interspersed with tetraploid and hexaploid sequences.

Avena↗
PubMedDate not supplied

Surveillance of nosocomial cross-infections due to three Acinetobacter genospecies (Acinetobacter baumannii, genospecies 3 and genospecies 13) during a 10-Year Observation period: serotyping, macrorestriction analysis of Genomic DNA and antibiotic susceptibilities.

During a 10-year surveillance period, a total of 2,359 isolates comprising the genus Acinetobacter were recovered and identified presumptively with phenotypic tests. Genospecies 3 was the most common (n = 1,053), followed by genospecies 13 (n = 352), Acinetobacter baumannii (n = 335), Acinetobacter Iwoffi (n = 162), and genospecies 14 (n = 97); 100 isolates (4.2%) were categorized as questionable Acinetobacter. There were 34 clusters of putative nosocomial cross-infection due either to genospecies 3 (n = 16), A. baumannii (n = 10) or genospecies 13 (n = 8). Apart from 3 clusters due to two multiple-antibiotic-resistant strains of genospecies 13 and one strain of A. baumannii, respectively, there was no significant increase of antibiotic resistance discernible during the decade-long period of Acinetobacter surveillance.

Acinetobacter↗
PubMedDate not supplied

Cytology, immunohistochemistry and 3-dimensional reconstruction of adenoma malignum: a case report.

BACKGROUND: Cytologic diagnosis of adenoma malignum is not easy. A case of adenoma malignum was diagnosed cytologically. CASE: A 45-year-old woman was suspected of having adenoma malignum. Her chief complaint was a mucoid cervical discharge. Transvaginal ultrasound examination showed multiple cervical cysts, and peculiar clusters of cervical columnar cells showing a channellike structure were observed cytologically. Cytologic analysis detected tumor cells with increased euchromatin and stretched nuclear membranes with distinct eosinophilic nucleoli. Intranuclear cytoplasmic inclusion bodies and lobate or budlike nuclei were also observed. Immunohistochemically, both HIK-1083 and carcinoembryonic antigen (CEA) were positive in the histologic specimens, although only a few glands were positive for CEA. On 3-dimensional reconstruction of normal cervical tissue, glands showing similar calibers and straight lines also had a "weeping willow-shaped" growing pattern. In the adenoma malignum there were large and small glands showing a cumuliform pattern, and cystic dilation with discontinuity and fusion of glands could be seen. CONCLUSION: The nuclear findings mentioned above were thought to be diagnostic characteristics of adenoma malignum. Three-dimensional reconstruction seems to be a method that can aid in the diagnosis of adenoma malignum.

Adenocarcinoma↗
PubMed1997

Predicting patients' deterioration and recovery.

The purpose of this study was to identify patient cues that expert nurses identify as a patient moves to/from deterioration and/or recovery. The sample of 33 nurses was drawn from a medical intensive care unit (MICU). Data were collected through interviews regarding nurses' knowledge about caring for patients with acute gastrointestinal bleeding, heart failure/post-myocardial infarction, and pulmonary edema. Using the constant comparative technique, cues were identified and grouped into early, imminent, and late patterns for deterioration and into categories of early, midway, and complete for recovery. Rationales for the nurses' decisions included memories of patients with similar cues, using multiple not single cues, and clustering both physiological and psychological cues together. This study is a beginning effort toward validating nurses' intuitiveness and provides knowledge about expert practice that can be taught to novice practitioners and incorporated into protocols for care.

Adult↗
PubMed1989

Sedimented calcium in benign breast cysts: the full spectrum of mammographic presentations.

We retrospectively reviewed the mammograms of 318 patients that showed sedimented calcifications within benign breast cysts to describe the natural history and full spectrum of the mammographic appearances. Sedimented calcifications are seen in approximately 4% of symptomatic women undergoing mammography. Their recognition is important to avoid unnecessary workup, follow-up, or biopsy. Key to recognition is the difference in their radiographic features on lateral and craniocaudal views. The classic appearance is that of milk of calcium, seen as linear, curvilinear, or teacup-shaped particles on horizontal-beam lateral views and as ill-defined smudges on vertical-beam craniocaudal views. The most common presentation is multiple, bilateral, scattered and occasionally clustered calcifications within microcysts. Other presentations include milk of calcium within microcysts in a unilateral, clustered distribution; milk of calcium within macrocysts; sandlike calcifications (discrete particles rather than smudges on craniocaudal view) within cysts of various sizes; and rarely, milk of calcium within the lipid cysts of either fat necrosis or galactoceles. None of our cases has proved to be malignant. However, adjacent malignancies are a potential pitfall. We encountered eight patients with carcinoma presenting as clustered microcalcifications in a breast also containing typical sedimented calcifications. In each of these cases, the malignant calcifications could be distinguished by their mammographic appearance. The recognition of sedimented calcifications present in about 4% of symptomatic women undergoing mammography is important because these characteristic calcifications are an indication of benignity. Malignant-appearing microcalcifications found in the vicinity of sedimented calcifications can be distinguished and require biopsy.

Adult↗
PubMed2006

Differentiation of normal skin and melanoma using high resolution hyperspectral imaging.

We investigated the use of high resolution hyperspectral imaging microscopy to detect abnormalities in skin tissue using hematoxylin eosin stained preparations of normal and abnormal skin, benign nevi and melanomas. A goal of this study was to provide objective data that could be utilized by any researcher; and form the beginnings of a reference spectral data base. All spectral characterizations were acquired in percent transmission, and absorption, with contiguous wavelength acquisition between 400 and 800 nm; and a spectral resolution of approximately 1 nm. Biopsy sections were characterized with varying sample thickness, staining and magnification in order to determine their impact on spectral characterizations. Spectra were classified using spectral waveform cross correlation analysis, an algorithm that is linearity invariant. Classified spectra were incorporated into spectral libraries; and all spectra acquired from the field of view were correlated with library spectra to a quantified, user determined, confidence threshold (minimum correlation coefficient). The results revealed that all skin conditions in our initial data sets could be objectively differentiated providing that staining and section thickness was controlled. We also demonstrated that it is likely that a reference spectral library database could be created to include bioinformatics and cluster analysis. This would assist multiple laboratories to participate in the input and retrieval of target spectral information.

Biopsy↗
PubMed1988

The bialaphos biosynthetic genes of Streptomyces hygroscopicus: cloning and analysis of the genes involved in the alanylation step.

We have isolated and studied the genes involved in the alanylation step in the biosynthesis of a herbicide, bialaphos which is produced by Streptomyces hygroscopicus. Three bialaphos-nonproducing mutants, NP60, NP61 and NP62, isolated from S. hygroscopicus by treatment with N-methyl-N'-nitro-N-nitrosoguanidine were defective for the alanylation step and were not restored to productivity by any locus of the gene cluster previously cloned. Three plasmids were isolated using NP60, NP61 and NP62 as recipients. The genes which restored productivity to NP61 and NP62 hybridized to the contiguous region of the bialaphos biosynthetic gene cluster. The gene cluster involved in the bialaphos production was about 35 kb long. The gene which restored productivity to NP60 did not hybridize to the bialaphos biosynthetic gene cluster. VM3 and VM4, putative alanylation blocked mutants, were derived from a bialaphos producer by gene replacement of an unidentified region of the biosynthetic gene cluster with an in vitro altered DNA sequence. The genes which restored productivity to VM3 and VM4 were located between the genes which code for phosphinomethylmalic acid synthase and demethylphosphinothricin acetyltransferase in the cluster. These results suggest that multiple genes are involved in the alanylation step.

Alanine↗
PubMed2000

[Functional organization of local neuronal networks in the cat neocortex. Dependence on the food motivation].

The multiple unit activity (MUA) from clusters of adjacent neurones in deep layers of the frontal and motor cortex was recorded in alert cats with different levels of alimentary motivation. Up to 7 spike trains were selected from the MUA. Neurones in the local circuits could be divided into 2 groups: large neurones with prevailing divergent characteristics, and small neurones with prevailing convergent characteristics. A 24-hour food deprivation altered the cross-correlation interneuronal connections with a time delay within the range of 2 to 100 ms.

Action Potentials↗
PubMed2002

Calcium secretion coupling at calyx of Held governed by nonuniform channel-vesicle topography.

Phasic transmitter release at synapses in the mammalian CNS is regulated by local [Ca2+] transients, which control the fusion of readily releasable vesicles docked at active zones (AZs) in the presynaptic membrane. The time course and amplitude of these [Ca2+] transients critically determine the time course and amplitude of the release and thus the frequency and amplitude tuning of the synaptic connection. As yet, the spatiotemporal nature of the [Ca2+] transients and the number and location of release-controlling Ca2+ channels relative to the vesicles, the "topography" of the release sites, have remained elusive. We used a time-dependent model to simulate Ca2+ influx, three-dimensional buffered Ca2+ diffusion, and the binding of Ca2+ to the release sensor. The parameters of the model were constrained by recent anatomical and biophysical data of the calyx of Held. Comparing the predictions of the model with previously measured release probabilities under a variety of experimental conditions, we inferred which release site topography is likely to operate at the calyx: At each AZ one or a few clusters of Ca2+ channels control the release of the vesicles. The distance of a vesicle to the cluster(s) varies across the multiple release sites of a single calyx (ranging from 30 to 300 nm; average approximately 100 nm). Assuming this topography, vesicles in different locations are exposed to different [Ca2+] transients, with peak amplitudes ranging from 0.5 to 40 microm (half-width approximately 400 microsec) during an action potential. Consequently the vesicles have different release probabilities ranging from <0.01 to 1. We demonstrate how this spatially heterogeneous release probability creates functional advantages for synaptic transmission.

Brain Stem↗
PubMed1992

Fine mapping of the McLeod locus (XK) to a 150-380-kb region in Xp21.

McLeod syndrome, characterized by acanthocytosis and the absence of a red-blood-cell Kell antigen (Kx), is a multisystem disorder involving a late-onset myopathy, splenomegaly, and neurological defects. The locus for this syndrome has been mapped, by deletion analysis, to a region between the loci for Duchenne muscular dystrophy (DMD) and chronic granulomatous disease (CGD). In this study, we describe a new marker, 3BH/R 0.3 (DXS 709), isolated by cloning the deletion breakpoint of a DMD patient. A long-range restriction map of Xp21, encompassing the gene loci for McLeod and CGD, was constructed, and multiple CpG islands were found clustered in a 700-kb region. Using the new marker, we have limited the McLeod syndrome critical region to 150-380-kb. Within this interval, two CpG-rich islands which may represent candidate sites for the McLeod gene were identified.

Blotting, Southern↗