Microbial community structure of a pilot-scale thermophilic anaerobic digester treating poultry litter

The microbial community structure of a stable pilot-scale thermophilic continuous stirred tank reactor digester stabilized on poultry litter was investigated. This 40-m³ digester produced biogas with 57 % methane, and chemical oxygen demand removal of 54 %. Bacterial and archaeal diversity were examined using both cloning and pyrosequencing that targeted 16S rRNA genes. The bacterial community was dominated by phylum Firmicutes, constituting 93 % of the clones and 76 % of the pyrotags. Of the Firmicutes, class Clostridia (52 % pyrotags) was most abundant followed by class Bacilli (13 % pyrotags). The bacterial libraries identified 94 operational taxonomic units (OTUs) and pyrosequencing identified 577 OTUs at the 97 % minimum similarity level. Fifteen OTUs were dominant (≥2 % abundance), and nine of these were novel unclassified Firmicutes. Several of the dominant OTUs could not be classified more specifically than Clostridiales, but were most similar to plant biomass degraders, including Clostridium thermocellum. Of the rare pyrotag OTUs (<0.5 % abundance), 75 % were Firmicutes. The dominant methanogen was Methanothermobacter which has hydrogenotrophic metabolism, and accounted for >99 % of the archaeal clones. Based on the primary methanogen, as well as digester chemistry (high VA and ammonia levels), we propose that bacterial acetate oxidation is the primary pathway in this digester for the control of acetate levels.     

A histopathological and stereological study of liver damage in female rats caused by mercury vapor

We examined the possible effects of elemental mercury vapor on the liver of the female rats. We divided the animals into an untreated control group and an experimental group that was exposed to mercury vapor for 45 days. Liver samples were obtained for histological and stereological analysis. The total liver, parenchyma and sinusoid volumes were increased significantly in the mercury vapor treated group compared to controls. Also, the mean density, total number and mean nuclear diameter of hepatocytes, except for binucleated hepatocytes, was decreased in the experimental group compared to controls. Light and electron microscopy revealed alterations of liver structure of the experimental animals compared to controls.     

Historical biogeography and the evolution of the latitudinal gradient of species richness in the Papionini (Primata: Cercopithecidae)

We apply historical biogeography techniques to the macaques, baboons and their relatives (Primata: Papionini) and relate the inferred history of range shifts, and associated evolutionary events, to the latitudinal distribution of extant species, which is strongly tropical. The results of reversible parsimony, weighted ancestral area and dispersal-vicariance analyses all agree that Central Africa was part of the range of the ancestor of the tribe. Tropical regions with high current species richness (Central Africa, South-east Asia, Indonesia) have: (1) had a relatively long history of occupation, (2) experienced both a greater number and a greater average rate of speciation events and (3) given rise to more dispersal events to other regions. However, nested sister-taxon comparisons across the tribe show no overall association between differences in latitude and differences in rates of cladogenesis. Our historical reconstructions are largely consistent with previous hypotheses and fossil data, and suggest that both the passage of time since colonization and rates of cladogenesis have enhanced tropical species richness. Historical biogeography may thus considerably aid understanding of this and other spatial problems in macroecology.  © 2005 The Linnean Society of London, Biological Journal of the Linnean Society , 2005, 85 , 235–246.     

Antibodies to citrullinated proteins and differences in clinical progression of rheumatoid arthritis

Antibodies to citrullinated proteins (anti-cyclic-citrullinated peptide [anti-CCP] antibodies) are highly specific for rheumatoid arthritis (RA) and precede the onset of disease symptoms, indicating a pathogenetic role for these antibodies in RA. We recently showed that distinct genetic risk factors are associated with either anti-CCP-positive disease or anti-CCP-negative disease. These data are important as they indicate that distinct pathogenic mechanisms are underlying anti-CCP-positive disease or anti-CCP-negative disease. Likewise, these observations raise the question of whether anti-CCP-positive RA and anti-CCP-negative RA are clinically different disease entities. We therefore investigated whether RA patients with anti-CCP antibodies have a different clinical presentation and disease course compared with patients without these autoantibodies. In a cohort of 454 incident patients with RA, 228 patients were anti-CCP-positive and 226 patients were anti-CCP-negative. The early symptoms, tender and swollen joint count, and C-reactive protein level at inclusion, as well as the swollen joint count and radiological destruction during 4 years of follow-up, were compared for the two groups. There were no differences in morning stiffness, type, location and distribution of early symptoms, patients' rated disease activity and C-reactive protein at inclusion between RA patients with and without anti-CCP antibodies. The mean tender and swollen joint count for the different joints at inclusion was similar. At follow-up, patients with anti-CCP antibodies had more swollen joints and more severe radiological destruction. Nevertheless, the distribution of affected joints, for swelling, bone erosions and joint space narrowing, was similar. In conclusion, the phenotype of RA patients with or without anti-CCP antibodies is similar with respect to clinical presentation but differs with respect to disease course.     

Prevalence of methotrexate intolerance in rheumatoid arthritis and psoriatic arthritis

Introduction

The aim of this study was to determine the prevalence of gastrointestinal and behavioural symptoms occurring before (anticipatory/associative) and after methotrexate (MTX) administration, termed MTX intolerance, in rheumatoid (RA) and psoriatic arthritis (PsA).

Methods

Methotrexate Intolerance Severity Score (MISS), previously validated in juvenile idiopathic arthritis patients, was used to determine MTX intolerance prevalence in 291 RA/PsA patients. The MISS consisted of four domains: abdominal pain, nausea, vomiting and behavioural symptoms, occurring upon, prior to (anticipatory) and when thinking of MTX (associative). MTX intolerance was defined as ≥6 on the MISS with ≥1 point on anticipatory and/or associative and/or behavioural items.

Results

A total of 123 patients (42.3%) experienced at least one gastrointestinal adverse effect. The prevalence of MTX intolerance was 11%. MTX intolerance prevalence was higher in patients on parenteral (20.6%) than on oral MTX (6.2%) (p < 0.001).

Conclusion

Besides well-known gastrointestinal symptoms after MTX, RA and PsA patients experienced these symptoms also before MTX intake. RA and PsA patients on MTX should be closely monitored with the MISS for early detection of MTX intolerance, in order to intervene timely and avoid discontinuation of an effective treatment.     

Biodegradation of the chlorophenoxy herbicide (R)-(+)-mecoprop by Alcaligenes denitrificans

An Alcaligenes denitrificans strain capable of utilizing theherbicide (R)-(+)-2(2-methyl-4-chlorophenoxy)propionicacid (mecoprop) as a sole carbon source was isolated fromsoil and cultured in liquid medium. Crude cell extracts of thebacterium were utilized in spectrophotometric assays toelucidate a biochemical pathway for degradation ofmecoprop. Results indicated a reaction sequence analogousto the degradation of 2,4-dichlorophenoxyacetic acid (2,4-D).GC-MS analysis provided direct evidence for thebiotransformation of mecoprop to the transient metabolite4-chloro-2-methylphenol (MCP). No NADPH-dependentactivity was observed during this reaction. Pyruvate wasverified as the second product derived from the aliphatic sidechain of mecoprop. MCP was subsequently transformed to asubstituted catechol by an NADPH-dependentmonooxygenase. When grown on mecoprop, A.denitrificans was adapted to oxidize catechol and its 4- and3-methylated derivatives indicating the broad substratespecificity of catechol dioxygenase. The microorganism wasdemonstrated to adopt the ortho mechanism of aromaticcleavage which resulted in the formation of2-methyl-4-carboxymethylene but-2-en-4-olide, a reactionintermediate of the -ketoadipate pathway.