Unique Regional Distribution Research Articles

Evaluation of multistage characteristics for coalbed methane desorption-diffusion and their geological controls: A case study of the northern Gujiao Block of Qinshui Basin, China

Based on the diverse geologic data and on-site desorption experimental results of No. 8 coal seam in northern Gujiao Block, a systematic investigation was conducted on multistage characteristics of coalbed methane (CBM) desorption-diffusion behaviors. Meanwhile, the comprehensive effects of geologic control factors and its implication for CBM production process were also studied. The results indicate that No. 8 coal seam has mainly experienced three deformation phases during early Yanshanian-Himalayan orogeny. Hereinto, the tectonic deformation occurred with superposition of various stages and scales dominate the regional distribution of tectonically deformed coals in the study area. A mathematical method was established to identify the turning time and decay time, which quantitatively divides the CBM desorption process into three stages. Moreover, the on-site CBM desorption data can be well fitted by the multiporous diffusion model, indicating that the CBM diffusion process also has obvious three-stage characteristics. Due to synthetic effects of coal destruction degree and the heterogeneous distribution of gas content/burial depth, CBM desorption-diffusion characteristics demonstrate the unique regional distribution in the deep buried area near Malan syncline axis, the graben structure region of central Tunlan area and the south-central Dongqu area. On this basis, three typical modes of CBM desorption-diffusion behaviors were distinguished in northern Gujiao Block. It specifies the comprehensive influence of geologic control factors on CBM desorption-diffusion process and its impact on gas production characteristics of CBM wells. Therefore, these investigations can provide support for the preliminary forecasting and simulation of CBM production.

A six-member SNP assay on the iPlex MassARRAY platform provides a rapid and affordable alternative for typing major African Staphylococcus aureus types.

Purpose Data on the clonal distribution of Staphylococcus aureus in Africa are scanty, partly due to the high costs and long turnaround times imposed by conventional genotyping methods such as spa and multilocus sequence typing (MLST), which means there is a need for alternative typing approaches. This study evaluated the discriminatory power, cost of and time required for genotyping Kenyan staphylococcal isolates using iPlex MassARRAY compared to conventional methods.Methodology Fifty-four clinical S. aureus isolates from three counties were characterized using iPlex MassARRAY, spa and MLST typing methods. Ten single-nucleotide polymorphisms (SNPs) from the S. aureus MLST loci were assessed by MassARRAY.>Results The MassARRAY assay identified 14 unique SNP genotypes, while spa typing and MLST revealed 22 spa types and 21 sequence types (STs) that displayed unique regional distribution. spa type t355 (ST152) was the dominant type overall while t037/t2029 (ST 241) dominated among the methicillin-resistant S. aureus (MRSA) isolates. MassARRAY showed 83 % and 82 % accuracy against spa typing and MLST, respectively, in isolate classification. Moreover, MassARRAY identified all MRSA strains and a novel spa type. MassARRAY had a reduced turnaround time (<12 h) compared to spa typing (4 days) and MLST (20 days). The MassARRAY reagent and consumable costs per isolate were approximately $18 USD compared to spa typing ($30 USD) and MLST ($126 USD).Conclusion This study demonstrated that iPlex MassARRAY can be adapted as a useful surveillance tool to provide a faster, more affordable and fairly accurate method for genotyping African S. aureus isolates to identify clinically significant genotypes, MRSA strains and emerging strain types.

Scrub typhus in Japan: epidemiology and clinical features of cases reported in 1998.

Surveillance for scrub typhus was conducted in Japan in 1998 using a questionnaire. A total of 462 cases were reported. Scrub typhus occurred in both the fall and spring in the northern part of Honshu (the main island), and in the fall in the central part of Honshu and on the island of Kyushu. The occurrence of the disease varied with age, gender, and activity. Seventy-six percent of the patients were more than 51 years old, and 36% and 16% of the patients were engaged in farm work and forestry, respectively. Fever, rash, and eschar were detected in 98%, 93%, and 97% of the patients, respectively. Elevated levels of C-reactive protein, aspartate transaminase, and alanine transaminase were detected in 96%, 87%, and 77% of the patients, respectively. Disseminated intravascular coagulation developed in 34 cases and had a unique regional distribution. This study shows the status of scrub typhus in Japan in 1998 and provides important information for diagnosis and prevention.

Generation of the mu opioid receptor (MOR-1) protein by three new splice variants of the Oprm gene.

Using 5' RACE, we have isolated four additional exons of the mu opioid receptor gene (Oprm), resulting in a gene spanning over 250 kb. The four new exons are contained within eight additional splice variants containing exon 11 at the 5' terminus. Exon 11, which is under the control of a previously unknown upstream promoter, and exon 12 are located approximately 10 kb and approximately 8 kb upstream from exon 1, respectively. Exon 13 and 14 are located between exons 1 and 2. The regional distributions of the variants, as determined by reverse transcription-PCR, varied among themselves and were distinct from that of MOR-1, implying region-specific RNA processing. Three variants (MOR-1H, MOR-1I, and MOR-1J) contained two potential translational start points, with the translational start point in exon 1 producing proteins identical to the original MOR-1 protein. When expressed, the receptor binding of these three variants was indistinguishable from that of MOR-1. The remaining eight proteins using the translation start point in exon 11 were all truncated, with three (MOR-1G, MOR-1M, and MOR-1N) predicting proteins of only six transmembrane domains and the rest giving proteins under 10 kDa. Western blots with an exon 11-specific antiserum revealed bands consistent with the six transmembrane domain proteins within the brain, but the shorter proteins were not detected. Thus, the MOR-1 protein can be generated by four different splice variants of the Oprm gene under the control of two physically distinct promoters. Although the truncated proteins are expressed in brain with a unique regional distribution, their functional significance remains unknown.

Dopamine receptor regulating factor, DRRF: a zinc finger transcription factor.

Dopamine receptor genes are under complex transcription control, determining their unique regional distribution in the brain. We describe here a zinc finger type transcription factor, designated dopamine receptor regulating factor (DRRF), which binds to GC and GT boxes in the D1A and D2 dopamine receptor promoters and effectively displaces Sp1 and Sp3 from these sequences. Consequently, DRRF can modulate the activity of these dopamine receptor promoters. Highest DRRF mRNA levels are found in brain with a specific regional distribution including olfactory bulb and tubercle, nucleus accumbens, striatum, hippocampus, amygdala, and frontal cortex. Many of these brain regions also express abundant levels of various dopamine receptors. In vivo, DRRF itself can be regulated by manipulations of dopaminergic transmission. Mice treated with drugs that increase extracellular striatal dopamine levels (cocaine), block dopamine receptors (haloperidol), or destroy dopamine terminals (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) show significant alterations in DRRF mRNA. The latter observations provide a basis for dopamine receptor regulation after these manipulations. We conclude that DRRF is important for modulating dopaminergic transmission in the brain.

Anatomical distribution of sodium-dependent [(3)H]naloxone binding sites in rat brain.

The sulfhydryl alkylating reagent N-ethylmaleimide (NEM) blocks opioid receptor binding and receptor/G-protein coupling. Sodium partially restores [(3)H]naloxone binding after inhibition by NEM to reveal sodium-dependent [(3)H]naloxone sites, defined as binding in the presence of 50-100 mM NaCl after treatment of membranes or sections with 750 microM NEM. In the present study, receptor autoradiography of [(3)H]naloxone binding in control and NEM-treated tissue was used to examine the anatomical distribution of sodium-dependent [(3)H]naloxone sites in rat brain. In brain membranes, the pharmacology of sodium-dependent [(3)H]naloxone sites was consistent with that of mu opioid receptors. Relatively high IC(50) values for agonists and lack of effect of Gpp(NH)p on DAMGO displacement of [(3)H]naloxone binding in NEM-treated membranes indicated that the sodium-dependent sites were low affinity sites, presumably uncoupled from G-proteins. Autoradiograms revealed that NEM treatment dramatically reduced [(3)H]naloxone binding in all brain regions. However, [(3)H]naloxone binding was increased in specific regions in NEM-treated sections in the presence of sodium, including bed nucleus of the stria terminalis, interpeduncular nucleus, periaqueductal gray, parabrachial nucleus, locus coeruleus, and commissural nucleus tractus solitarius. Sodium-dependent [(3)H]naloxone binding sites were not found in other areas that exhibited [(3)H]naloxone binding in control tissue, including the striatum and thalamus. These studies revealed the presence of a subpopulation of [(3)H]naloxone binding sites which are sodium-dependent and have a unique regional distribution in the rat brain.

Identification of a high-affinity orphanin FQ/nociceptin(1-11) binding site in mouse brain.

The presence of pairs of basic amino acids within the orphanin FQ/Nociceptin (OFQ/N) sequence has raised the possibility that truncated versions of the peptide might be physiologically important. OFQ/N(1-11) is pharmacologically active in mice, despite its poor affinity in binding assays (K(i) > 250 nM) for the OFQ/N receptor. Using an analog of OFQ/N(1-11), [(125)I][Tyr(10)]OFQ/N(1-11), we identified a high-affinity binding site (K(D) 234 pM; B(max) 43 fmol/mg protein) with a selectivity profile distinct from the OFQ/N receptor and all the traditional opioid receptors. This site had very high affinity for OFQ/N and its related peptides. The most striking differences between the new site and the OFQ/N receptor previously observed in brain were seen with traditional opioids. Dynorphin A analogs and alpha-neoendorphin competed with [(125)I][Tyr(10)]OFQ/N(1-11) binding in mouse brain with K(i) values below 10 nM, while naloxone benzoylhydrazone (K(i) 3.9 nM) labeled the [(125)I][Tyr(10)]OFQ/N(1-11) binding site as potently as many traditional opioid receptors. Several other opioids, including fentanyl, (-)cyclazocine, levallorphan, naltrindole, and diprenorphine, also displayed moderate affinities for this site. Finally, the [(125)I][Tyr(10)]OFQ/N(1-11) site had a unique regional distribution consistent with a distinct receptor. Thus, [(125)I][Tyr(10)]OFQ/N(1-11) labels a novel site in brain with a selectivity profile intermediate between that of either opioid or OFQ/N receptors.

Quantitative autoradiography of M 2 muscarinic receptors in the rat brain identified by using a selective radioligand [ 3H]AF-DX 116

Muscarinic receptors of the M 2 type have been studied in the rat brain using quantitative autoradiography with the selective ligand, [ 3H]AF-DX 116. High specific binding of [ 3H]AF-DX 116 was found in areas such as laminae IV and V of the parietal cerebral cortex, thalamus and hypothalamus and dentate gyrus. Intermediate [ 3H]AF-DX 116 binding was found in the frontal cortex, hippocampus, caudate-putamen, nucleus accumbens, and claustrum as well as in certain brainstem nuclei such as the nucleus of the solitary tract and the dorsal motor nuclei of the vagus. In contrast, the accessory olfactory nucleus, globus pallidus and cerebellum contained very low concentrations of M 2 receptors. The present study demonstrates a unique regional distribution of M 2 receptors in the rat brain.

Sialyl glycoprotein distribution on the plasma membrane of ejaculated ram spermatozoa.

Localization of sialyl residues on unfixed ejaculated ram sperm membrane using the direct covalent probes of either ferritin hydrazide or latex hydrazide revealed a unique regional distribution on the plasmalemma covering the sperm head only. Three different labelling zones were identified based on the intensity and the nature of the sialyl glycoconjugates: a patchy-like zone which included the plasma membrane overlaying the post-nuclear cap and the convex side of the apical body of the acrosome; highly ordered heavily labelled zones including the plasmalemma adjacent to the concave apical body of the acrosome and to the posterior part of the equatorial acrosomal segment; a paucity-labelling zone which included the plasma membrane underlying the principal acrosomal region and the anterior part of the equatorial acrosomal segment. The possible physiological role of the highly ordered labelled zones is discussed.

Glutamate and related amino acids in cat spinal roots, dorsal root ganglia and peripheral nerves.

Abstract—Of the free amino acids found in extracts of cat spinal roots, dorsal root ganglia and peripheral nerves, only glutamate was present in disproportionately high concentrations in those parts of the dorsal roots between ganglia and spinal cord. This distribution suggests that the high dorsal root levels of glutamate may result from synthesis in dorsal root ganglia and subsequent transport towards the spinal cord. Four excitant amino acids were detected in the extracts: aspartate, cysteate, cysteine sulphinate and glutamate. The unique regional distribution of glutamate is consistent with the proposed role of this amino acid as an excitatory transmitter at the terminals of primary afferent fibres.