The thyroid gland secretes primarily tetraiodothyronine (T4), and some triiodothyronine (T3). Under normal physiological circumstances, only one-fifth of circulating T3 is directly released by the thyroid, but in states of hyperactivation of thyroid-stimulating hormone receptors (TSHRs), patients develop a syndrome of relative T3 toxicosis. Thyroidal T4 production results from iodination of thyroglobulin (TG) at residues Tyr(5) and Tyr(130), whereas thyroidal T3 production may originate in several different ways. In this study, the data demonstrate that within the carboxyl-terminal portion of mouse TG, T3 is formed de novo independently of deiodination from T4 We found that upon iodination in vitro, de novo T3 formation in TG was decreased in mice lacking TSHRs. Conversely, de novo T3 that can be formed upon iodination of TG secreted from PCCL3 (rat thyrocyte) cells was augmented from cells previously exposed to increased TSH, a TSHR agonist, a cAMP analog, or a TSHR-stimulating antibody. We present data suggesting that TSH-stimulated TG phosphorylation contributes to enhanced de novo T3 formation. These effects were reversed within a few days after removal of the hyperstimulating conditions. Indeed, direct exposure of PCCL3 cells to human serum from two patients with Graves' disease, but not control sera, led to secretion of TG with an increased intrinsic ability to form T3 upon in vitro iodination. Furthermore, TG secreted from human thyrocyte cultures hyperstimulated with TSH also showed an increased intrinsic ability to form T3 Our data support the hypothesis that TG processing in the secretory pathway of TSHR-hyperstimulated thyrocytes alters the structure of the iodination substrate in a way that enhances de novo T3 formation, contributing to the relative T3 toxicosis of Graves' disease.
The whole genomes for six botulinum neurotoxin-producing clostridial strains were sequenced to provide references for under-represented toxin types, bivalent strains or unusual toxin complexes associated with a bont gene. The strains include three Clostridium botulinum Group I strains (CDC 297, CDC 1436, and Prevot 594), a Group II C. botulinum strain (Eklund 202F), a Group IV Clostridium argentinense strain (CDC 2741), and a Group V Clostridium baratii strain (Sullivan). Comparisons of the Group I genomic sequences revealed close relationships and conservation of toxin gene locations with previously published Group I C. botulinum genomes. The bont/F6 gene of strain Eklund 202F was determined to be a chimeric toxin gene composed of bont/F1 and bont/F2. The serotype G strain CDC 2741 remained unfinished in 20 contigs with the bont/G located within a 1.15Mb contig, indicating a possible chromosomal location for this toxin gene. Within the genome of C. baratii Sullivan strain, direct repeats of IS1182 insertion sequence (IS) elements were identified flanking the bont/F7 toxin complex that may be the mechanism of bont insertion into C. baratii. Highlights of the six strains are described and release of their genomic sequences will allow further study of unusual neurotoxin-producing clostridial strains.
        
Title: Use of hydrophilic ionic liquids in a two-phase system to improve Mung bean epoxide hydrolases-mediated asymmetric hydrolysis of styrene oxide Chen WJ, Lou WY, Yu CY, Wu H, Zong MH, Smith TJ Ref: J Biotechnol, 162:183, 2012 : PubMed
A comparative study was made of Mung bean epoxide hydrolases-catalyzed asymmetric hydrolysis of styrene oxide to (R)-1-phenyl-1,2-ethanediol in an n-hexane/buffer biphasic system containing various hydrophilic ionic liquids (ILs). Compared to the n-hexane/buffer biphasic system alone, addition of a small amount of hydrophilic ILs reduced the amount of non-enzymatic hydrolysis, and improved the reaction rate by up to 22%. The ILs with cation containing an alkanol group, namely [C(2)OHMIM][BF(4)] and [C(2)OHMIM][TfO], and the choline amino acid ILs [Ch][Arg] and [Ch][Pro] were found to be the most suitable co-solvents for the reaction, owing to their good biocompatibility with the enzyme, which led to high initial rates (0.99-1.25mumol/min) and high product e.e.s (95%). When substrate concentration was around 30mM, where optimal performance was observed with the IL-containing systems, the product e.e. was improved from 90% without ILs to >/=95% in the presence of ILs.
        
Title: A highly regioselective route to arbutin esters by immobilized lipase from Penicillium expansum Yang RL, Li N, Li RF, Smith TJ, Zong MH Ref: Bioresour Technol, 101:1, 2010 : PubMed
Immobilized lipase from Penicillium expansum, a novel and inexpensive enzyme preparation that we immobilized in our laboratory, was an excellent catalyst for highly regioselective acylation of arbutin with fatty acid vinyl esters. For the enzymatic butanoylation of arbutin, under the optimal conditions, initial reaction rate was 75.1 mM/h, and substrate conversion and regioselectivity were greater than 99%. In addition, a variety of 6'-esters of arbutin were prepared with high conversion (>99%) and excellent regioselectivity (>99%). It was found that the enzymatic reaction rate varied widely with different acyl donors, presumably owing to their different interactions with the active site of the lipase. The immobilized lipase from P. expansum displayed highest catalytic activity with medium-length straight-chain acyl donors. Acyl donors bearing a substituent or a conjugate double bond gave reduced reaction rates.
BACKGROUND: Clostridium botulinum and related clostridial species express extremely potent neurotoxins known as botulinum neurotoxins (BoNTs) that cause long-lasting, potentially fatal intoxications in humans and other mammals. The amino acid variation within the BoNT is used to categorize the species into seven immunologically distinct BoNT serotypes (A-G) which are further divided into subtypes. The BoNTs are located within two generally conserved gene arrangements known as botulinum progenitor complexes which encode toxin-associated proteins involved in toxin stability and expression. METHODOLOGY/PRINCIPAL FINDINGS: Because serotype A and B strains are responsible for the vast majority of human botulism cases worldwide, the location, arrangement and sequences of genes from eight different toxin complexes representing four different BoNT/A subtypes (BoNT/A1-Ba4) and one BoNT/B1 strain were examined. The bivalent Ba4 strain contained both the BoNT/A4 and BoNT/bvB toxin clusters. The arrangements of the BoNT/A3 and BoNT/A4 subtypes differed from the BoNT/A1 strains and were similar to those of BoNT/A2. However, unlike the BoNT/A2 subtype, the toxin complex genes of BoNT/A3 and BoNT/A4 were found within large plasmids and not within the chromosome. In the Ba4 strain, both BoNT toxin clusters (A4 and bivalent B) were located within the same 270 kb plasmid, separated by 97 kb. Complete genomic sequencing of the BoNT/B1 strain also revealed that its toxin complex genes were located within a 149 kb plasmid and the BoNT/A3 complex is within a 267 kb plasmid. CONCLUSIONS/SIGNIFICANCE: Despite their size differences and the BoNT genes they contain, the three plasmids containing these toxin cluster genes share significant sequence identity. The presence of partial insertion sequence (IS) elements, evidence of recombination/gene duplication events, and the discovery of the BoNT/A3, BoNT/Ba4 and BoNT/B1 toxin complex genes within plasmids illustrate the different mechanisms by which these genes move among diverse genetic backgrounds of C. botulinum.
        
Title: Effects of switching pravastatin to cerivastatin on C-reactive protein, butyrylcholinesterase, and lipids Shinn AH, Carr-Lopez SM, Smith JW, Elledge EA, Smith TJ Ref: Curr Med Res Opin, 21:207, 2005 : PubMed
OBJECTIVE: C-reactive protein (CRP) concentrations, butyrylcholinesterase (BChE) activity, total cholesterol (TC), low-density lipoprotein (LDL), high-density lipoprotein (HDL), and triglycerides (TG) were evaluated in patients switched from pravastatin to cerivastatin. The purpose of this study was to determine whether a more potent statin (cerivastatin) would further affect CRP, whether a relation ship between CRP and BChE existed, and if there were any relationships between CRP or BChE and lipids. In view of the withdrawal of cerivastatin from the market, studies considering the effects of conversion of patients from one statin to another are warranted. RESEARCH DESIGN AND METHODS: Thirty-seven patients actively taking pravastatin (10 mg-40 mg) were switched to cerivastatin (0.2 mg-0.8 mg) at the initial visit in the Lipid Clinic at David Grant Medical Center, Travis Air Force Base. Samples were collected before the conversion (pravastatin phase) and at 6 weeks and 12 weeks post-conversion. Patients were excluded from the study if they were taking gemfibrozil concomitantly. Patients were counseled on the adverse effects of cerivastatin, including rhabdomyolsis. RESULTS: Median CRP levels at the pravastatin phase, 6 weeks of cerivastatin, and 12 weeks of cerivastatin, were 0.380 mg/dL, 0.403 mg/dL, and 0.364 mg/dL (p = 0.772), respectively. Median BChE activity at the pravastatin phase, 6 weeks of cerivastatin, and 12 weeks of cerivastatin were 0.338 micromol/mL/min, 0.332 micromol/mL/min, 0.33 micromol/mL/min (p = 0.746), respectively. A negative correlation was observed between CRP and BChE at baseline only (r = -0.353, p = 0.032). There was a significant decline in mean TC (p < 0.001) and median LDL (p < 0.001) and a significant increase in mean HDL (p = 0.017) over the three time points. Numerically TG declined, but it was not statistically significant (p = 0.649). No correlations were observed between CRP or BChE and any of the lipids. Gender, aspirin use, and the presence of CHD or diabetes did not affect CRP levels or BChE activity. CONCLUSION: Median CRP remained stable with pravastatin and cerivastatin use, although TC and LDL decreased. The further decline observed with LDL, but not CRP suggests differing effects of statins on LDL and CRP. Limitations include no serum levels prior to statin use and small sample size; thus, future studies are needed to address the relationship between cholesterol and CRP and the mechanism of action of statins on CRP.
Anopheles gambiae is the principal vector of malaria, a disease that afflicts more than 500 million people and causes more than 1 million deaths each year. Tenfold shotgun sequence coverage was obtained from the PEST strain of A. gambiae and assembled into scaffolds that span 278 million base pairs. A total of 91% of the genome was organized in 303 scaffolds; the largest scaffold was 23.1 million base pairs. There was substantial genetic variation within this strain, and the apparent existence of two haplotypes of approximately equal frequency ("dual haplotypes") in a substantial fraction of the genome likely reflects the outbred nature of the PEST strain. The sequence produced a conservative inference of more than 400,000 single-nucleotide polymorphisms that showed a markedly bimodal density distribution. Analysis of the genome sequence revealed strong evidence for about 14,000 protein-encoding transcripts. Prominent expansions in specific families of proteins likely involved in cell adhesion and immunity were noted. An expressed sequence tag analysis of genes regulated by blood feeding provided insights into the physiological adaptations of a hematophagous insect.
The high degree of similarity between the mouse and human genomes is demonstrated through analysis of the sequence of mouse chromosome 16 (Mmu 16), which was obtained as part of a whole-genome shotgun assembly of the mouse genome. The mouse genome is about 10% smaller than the human genome, owing to a lower repetitive DNA content. Comparison of the structure and protein-coding potential of Mmu 16 with that of the homologous segments of the human genome identifies regions of conserved synteny with human chromosomes (Hsa) 3, 8, 12, 16, 21, and 22. Gene content and order are highly conserved between Mmu 16 and the syntenic blocks of the human genome. Of the 731 predicted genes on Mmu 16, 509 align with orthologs on the corresponding portions of the human genome, 44 are likely paralogous to these genes, and 164 genes have homologs elsewhere in the human genome; there are 14 genes for which we could find no human counterpart.