A novel family of single VWC-domain proteins in invertebrates

Using a combination of sequence analysis tools, a novel family of 13 short Drosophila melanogaster proteins with similarity to a single von Willebrand factor C-domain (SVC proteins) has been identified. SVCs are predicted to be secreted and a structural model for the family is proposed, using a known von Willebrand factor C-domain (VWC) structure as template. All SVCs possess eight cysteines, consistent with the loss of one bonded pair from the 10-cysteine canonical pattern of most VWC domains. Unlike most Drosophila genes, many SVCs are not expressed during development, and misexpression has no apparent effect on development or viability. SVCs appear to be restricted to arthropods. A role for SVCs in response to environmental challenges is proposed.     

Similar patterns of age‐specific reproduction in an island and mainland population of great tits Parus major

The process of ageing was long thought to be too infrequent to affect life‐histories in natural populations. Long‐term studies have, however, recently demonstrated ageing to be ubiquitous even in the wild, although confounding factors, such as emigration instead of mortality, or inter‐population variation in rates of ageing have seldom been addressed. Here, we present analyses of female age‐specific reproductive performance in a Dutch island population of great tits Parus major. For this population with limited connectivity to surrounding areas, we show that, between individuals, reproductive lifespan positively co‐varies with recruit production, while within individuals performance improves up to 3 years of age, after which it gradually declines. We also show these patterns to be strikingly similar to those recently found in a less isolated British mainland population of great tits, characterised by different environmental conditions and life‐history strategies, in particular the frequency of multiple breeding. Our results therefore suggest patterns of age‐specific reproductive performance to be robust to both environmental and life‐history variation.     

Expression of the Caldariomyces fumago chloroperoxidase in Aspergillus niger and characterization of the recombinant enzyme

The Caldariomyces fumago chloroperoxidase was successfully expressed in Aspergillus niger. The recombinant enzyme was produced in the culture medium as an active protein and could be purified by a three-step purification procedure. The catalytic behavior of recombinant chloroperoxidase (rCPO) was studied and compared with that of native CPO. The specific chlorination activity (47 units/nmol) of rCPO and its pH optimum (pH 2.75) were very similar to those of native CPO. rCPO catalyzes the oxidation of various substrates in comparable yields and selectivities to native CPO. Indole was oxidized to 2-oxindole with 99% selectivity and thioanisole to the corresponding R-sulfoxide (enantiomeric excess >98%). Incorporation of (18)O from labeled H(2)18O(2) into the oxidized products was 100% in both cases.     

The FLF MADS box gene: a repressor of flowering in Arabidopsis regulated by vernalization and methylation

A MADS box gene, FLF (for FLOWERING LOCUS F ), isolated from a late-flowering, T-DNA-tagged Arabidopsis mutant, is a semidominant gene encoding a repressor of flowering. The FLF gene appears to integrate the vernalization-dependent and autonomous flowering pathways because its expression is regulated by genes in both pathways. The level of FLF mRNA is downregulated by vernalization and by a decrease in genomic DNA methylation, which is consistent with our previous suggestion that vernalization acts to induce flowering through changes in gene activity that are mediated through a reduction in DNA methylation. The flf-1 mutant requires a greater than normal amount of an exogenous gibberellin (GA3) to decrease flowering time compared with the wild type or with vernalization-responsive late-flowering mutants, suggesting that the FLF gene product may block the promotion of flowering by GAs. FLF maps to a region on chromosome 5 near the FLOWERING LOCUS C gene, which is a semidominant repressor of flowering in late-flowering ecotypes of Arabidopsis.     

Mitomycin resistance in Streptomyces lavendulae includes a novel drug-binding-protein-dependent export system

Sequence analysis of Streptomyces lavendulae NRRL 2564 chromosomal DNA adjacent to the mitomycin resistance locus mrd (encoding a previously described mitomycin-binding protein [P. Sheldon, D. A. Johnson, P. R. August, H.-W. Liu, and D. H. Sherman, J. Bacteriol. 179:1796-1804, 1997]) revealed a putative mitomycin C (MC) transport gene (mct) encoding a hydrophobic polypeptide that has significant amino acid sequence similarity with several actinomycete antibiotic export proteins. Disruption of mct by insertional inactivation resulted in an S. lavendulae mutant strain that was considerably more sensitive to MC. Expression of mct in Escherichia coli conferred a fivefold increase in cellular resistance to MC, led to the synthesis of a membrane-associated protein, and correlated with reduced intracellular accumulation of the drug. Coexpression of mct and mrd in E. coli resulted in a 150-fold increase in resistance, as well as reduced intracellular accumulation of MC. Taken together, these data provide evidence that MRD and Mct function as components of a novel drug export system specific to the mitomycins.     

Case report: Cutaneous nocardiosis complicating management of Crohn's disease with infliximab and prednisone

INFLIXIMAB IS A CHIMERIC ANTI-TUMOUR NECROSIS FACTOR-α antibody that is efficacious in treating Crohn''s disease. However, its immunomodulatory properties increase susceptibility to opportunistic infections. We present a case of cutaneous Nocardia infection in a patient who was taking infliximab for Crohn''s disease. The case illustrates the challenges in the diagnosis and management of this disease and serves as a reminder of the complications associated with the use of immunomodulatory agents.A 45-year-old HIV-negative man with fistulous Crohn''s disease had a history of inadequate disease control despite ongoing prednisone therapy. He had previously taken budesonide, mesalamine, ciprofloxacin and metronidazole in attempts to induce remission of his inflammatory bowel disease. The patient was born in Canada and, other than a 1-week holiday to Mexico 10 years before presentation, had travelled only locally. He denied a family history of tuberculosis, and he had never worked in a health care facility. Infliximab was introduced, and the patient received 3 infusions of 5 mg/kg at baseline and 2 and 6 weeks later. After he received his third infusion, prednisone was tapered to 40 mg at a rate of 5 mg weekly. One month after the third infusion, in February 2000, he reported multiple erythematous papulopustular lesions on his right leg (Fig. 1). There was no associated lymphadenopathy, cough, shortness of breath, fever or constitutional symptoms. He denied a history of insect bites, but in November 1999 he had received cuts to his right leg from a metal blade when at work. He had not immersed the leg in a whirlpool or swimming pool around the time of the leg injury. The patient continued to receive further infliximab infusions (at weeks 12 and 18 after baseline), and the lesions were treated with cloxacillin for suspected Staphylococcus aureus infection. Since improvement was minimal, a skin biopsy was performed in July 2000. Granulomatous inflammation was present, and acid-fast bacilli were visualized (Fig. 2). Cultures sent for mycobacteriology and mycology were incubated at 35°C for 8 weeks, but the results from the mycobacteriology culture proved negative. A polymerase chain reaction assay for Mycobacterium tuberculosus was also negative. A clinical diagnosis of M. marinum infection was made, and the patient''s antibiotic regimen was changed to minocycline. A tuberculin skin test was not performed; since the patient was immunocompromised, a negative result would not have excluded the disease. A chest radiograph appeared normal.Open in a separate windowFig. 2: Acid-fast bacilli visualized in skin biopsy.Open in a separate windowFig. 1: Multiple erythematous papulopustular lesions on the patient''s leg 1 month after the third infusion of infliximab.The patient failed to respond to the minocycline therapy, and he was referred for infectious disease consultation in October 2000. The infliximab infusions were discontinued, and 2 more skin biopsies were performed, with acid-fast bacilli visualized in both specimens. The patient was given trimethoprim–sulfamethoxazole, and his lesions began to heal slowly but progressively.Acid-fast bacilli were recovered from the second set of biopsies, and specific instructions were given to incubate the cultures at 30°C and 35°C to ensure that M. marinum, if present, would be detected. Again, the cultures failed to recover organisms. The laboratory, using polymerase chain reaction restriction analysis of the 439-base pair segment of the gene encoding a 65-kDa heat shock protein,¹ identified the presence of Nocardia species. Nevertheless, Nocardia organisms still could not be recovered in culture, and therefore final speciation could not be performed.The patient resumed taking prednisone, and the dosage was increased in order to ameliorate the symptoms of his Crohn''s disease. The trimethoprim–sulfamethoxazole therapy was continued until late 2003, and the dosage was reduced over the subsequent months. Complete healing of the lesions was eventually achieved 4 years after therapy was initiated.     

Xylose fermentation by genetically modified Saccharomyces cerevisiae 259ST in spent sulfite liquor

Spent sulfite pulping liquor (SSL) is a high-organic content byproduct of acid bisulfite pulp manufacture which is fermented to make industrial ethanol. SSL is typically concentrated to 240 g/l (22% w/w) total solids prior to fermentation, and contains up to 24 g/l xylose and 30 g/l hexose sugars, depending upon the wood species used. The xylose present in SSL is difficult to ferment using natural xylose-fermenting yeast strains due to the presence of inhibitory compounds, such as organic acids. Using sequential batch shake flask experiments, Saccharomyces cerevisiae 259ST, which had been genetically modified to ferment xylose, was compared with the parent strain, 259A, and an SSL adapted strain, T2, for ethanol production during SSL fermentation. With an initial SSL pH of 6, without nutrient addition or SSL pretreatment, the ethanol yield ranged from 0.32 to 0.42 g ethanol/g total sugar for 259ST, compared to 0.15-0.32 g ethanol/g total sugar for non-xylose fermenting strains. For most fermentations, minimal amounts of xylitol (<1 g/l) were produced, and glycerol yields were approximately 0.12 g glycerol/g sugar consumed. By using 259ST for SSL fermentation up to 130% more ethanol can be produced compared to fermentations using non-xylose fermenting yeast.