Development of a homologous transformation system for the opportunistic human pathogen Aspergillus fumigatus based on the sC gene encoding ATP sulfurylase.

The development of a homologous transformation system for the opportunistic human pathogenic fungus Aspergillus fumigatus is described. The system is based on the sC gene encoding ATP sulfurylase. Several A. fumigatus sC mutant strains were readily isolated by strong selection for selenate resistance. The coding region plus upstream and downstream regulatory sequences of the A. fumigatus sC gene were cloned by inverse PCR and then sequenced. Sequencing of the sC cDNA revealed the presence of five introns located within the first half of the gene. The A. fumigatus sC gene encodes a protein of 574 amino acids which is highly similar to ATP sulfurylases from the filamentous fungal species Aspergillus nidulans, Aspergillus terreus and Penicillium chrysogenum. By contrast, ATP sulfurylases from the yeasts Saccharomyces cerevisiae and Schizosaccharomyces pombe lack the C-terminal adenosine-5'-phosphosulfate kinase-like domain present in the filamentous fungal orthologues. A 3.8-kb DNA fragment amplified by PCR and containing the sC gene plus 5' and 3' flanking regions was cloned into pUC19 to give the vector pSCFUM. Transformation of two different sC mutant isolates with the plasmid pSCFUM established the functionality of this new homologous transformation system. Molecular analysis of sC+ transformants showed that up to 44% of transformed clones contained one or more copies of the entire plasmid integrated at the sC locus. This result also demonstrates the utility of the sC marker for targeting specific genetic constructs to the A. fumigatus sC locus, facilitating studies of gene regulation and function.

Annotated draft genomic sequence from a Streptococcus pneumoniae type 19F clinical isolate.

The public availability of numerous microbial genomes is enabling the analysis of bacterial biology in great detail and with an unprecedented, organism-wide and taxon-wide, broad scope. Streptococcus pneumoniae is one of the most important bacterial pathogens throughout the world. We present here sequences and functional annotations for 2.1-Mbp of pneumococcal DNA, covering more than 90% of the total estimated size of the genome. The sequenced strain is a clinical isolate resistant to macrolides and tetracycline. It carries a type 19F capsular locus, but multilocus sequence typing for several conserved genetic loci suggests that the strain sequenced belongs to a pneumococcal lineage that most often expresses a serotype 15 capsular polysaccharide. A total of 2,046 putative open reading frames (ORFs) longer than 100 amino acids were identified (average of 1,009 bp per ORF), including all described two-component systems and aminoacyl tRNA synthetases. Comparisons to other complete, or nearly complete, bacterial genomes were made and are presented in a graphical form for all the predicted proteins.

Identification of factors associated with poor peripheral blood progenitor cell mobilization in Hodgkin's disease.

BACKGROUND AND OBJECTIVES: Although the use of drugs which damage stem cells is common in patients with Hodgkin's disease (HD), factors affecting peripheral blood progenitor cell (PBPC) mobilization have not been clearly established in this group of patients. The aim of this study was to identify factors associated with poor PBPC mobilization in patients with HD. DESIGN AND METHODS: In order to address this issue we have evaluated in 54 patients with HD mobilized with G-CSF alone the following factors: sex, age, histologic subtype, B symptoms at diagnosis, status of remission, previous chemotherapy and radiotherapy, interval from diagnosis and last chemotherapy cycle to harvest, and dose of G-CSF. Univariate analysis was performed using Student's t-test, Pearson's correlation and Spearman's correlation. A stepwise regression model was used to determine which of the variables was the most predictive of PBPC mobilization. RESULTS: In univariate analysis poorer PBPC mobilization was observed in patients who had previously received at least two courses of mini-BEAM (p=0.006), a high number of different chemotherapy regimens (p=0.002), a chemotherapy score >30 (p=0.02) and more than 9 months of alkylating agents (p=0.07). We did not find radiotherapy to be a significant factor affecting progenitor cell yield (p=0.59). In the stepwise regression model, only the previous administration of two or more mini-BEAM cycles predicted a poor PBPC yield (p=0.006). INTERPRETATION AND CONCLUSIONS: Previous chemotherapy, principally exposure to a mini-BEAM regimen, seems to be the principal factor affecting collection of PBPC in patients with HD mobilized with G-CSF alone. Since mini-BEAM is an effective salvage regimen in relapsed or refractory HD, collection of PBPC should be planned when there has been no or only minimal exposure to a mini-BEAM regimen.

Three-dimensional cryo-electron microscopy localization of EF2 in the Saccharomyces cerevisiae 80S ribosome at 17.5 A resolution.

Using a sordarin derivative, an antifungal drug, it was possible to determine the structure of a eukaryotic ribosome small middle dotEF2 complex at 17.5 A resolution by three-dimensional (3D) cryo-electron microscopy. EF2 is directly visible in the 3D map and the overall arrangement of the complex from Saccharomyces cerevisiae corresponds to that previously seen in Escherichia coli. However, pronounced differences were found in two prominent regions. First, in the yeast system the interaction between the elongation factor and the stalk region of the large subunit is much more extensive. Secondly, domain IV of EF2 contains additional mass that appears to interact with the head of the 40S subunit and the region of the main bridge of the 60S subunit. The shape and position of domain IV of EF2 suggest that it might interact directly with P-site-bound tRNA.

BMT: Serum Ferritin as Risk Factor for Veno-occlusive Disease of the Liver. Prospective Cohort Study.

Veno-occlusive disease of the liver (VOD) is an important complication in hematological transplantation. The aim of this study is to analyze the risk factors for VOD and other forms of liver toxicity in a cohort of 180 peripheral stem cell transplants performed in our Center. We find that elevated pretransplant levels of serum ferritin are the most important risk marker for VOD. We believe that ferritin reflects damage induced by oxygen radicals resulting from iron-mediated catalysis. We also discuss different risk factors for VOD and other forms of liver toxicity, suggesting diferent pathogenic mechanisms.

Nitric oxide-producing CD11b(+)Ly-6G(Gr-1)(+)CD31(ER-MP12)(+) cells in the spleen of cyclophosphamide-treated mice: implications for T-cell responses in immunosuppressed mice.

During recovery from intensive chemotherapy with cyclophosphamide (CTX), mice suffer a severe but transitory impairment in spleen cell proliferation to T-cell mitogens (Con A or anti-CD3 plus IL-2). Although CTX treatment reduced spleen T-cell cellularity, this cannot fully account for T-cell unresponsiveness. The results showed that CTX induces the colonization of spleen by an immature myeloid CD11b(+)Ly-6G(+)CD31(+) population. Its presence closely correlated with the maximum inhibition of T-cell proliferation. Moreover, this suppressive activity was dependent on nitric oxide (NO) production in cultures since (1) higher amounts of nitric oxide and inducible nitric oxide synthase (iNOS) mRNA were produced in CTX spleen cells (CTX-SC) than in control splenocyte cultures and (2) NOS inhibitors greatly improved the proliferation of T lymphocytes. Nitric oxide production and suppressive activity were also dependent on endogenous interferon-gamma (IFN-gamma) production since anti-IFN-gamma abrogated both effects. Finally, iNOS protein expression was restricted to a heterogeneous population of CD31(+) cells in which CD11b(+)Ly-6G(+) cells were required to suppress T-cell proliferation. These results indicated that CTX might also cause immunosuppression by a mechanism involving the presence of immature myeloid cells with suppressor activity. This may have implications in clinical praxis since inappropriate immunotherapies in patients treated with intensive chemotherapy could lead to deleterious T-cell responses. (Blood. 2000;95:212-220)

A prospective randomized trial of granulocyte colony-stimulating factor therapy after autologous blood stem cell transplantation in adults.

In order to assess the potential clinical benefit of filgrastim (G-CSF) after peripheral blood stem cell (PBSC) autotransplantation a randomized study was begun in our center in July 1997: 62 patients were involved (30 received filgrastim after PBSC infusion and 32, the control group, received no cytokines). All were adults (median 40 years, range 18-65). Patients with one of three different pathologies were recruited: 28 had advanced breast carcinoma, 23 had lymphomas (12 Hodgkin's disease and 11 non-Hodgkin's lymphoma) and 11 had de novo AML. All of them were transplanted using myeloablative chemotherapy conditioning regimens. G-CSF was administered subcutaneously from day +5 in the treated group at a dose of 5 microg/kg body weight/day. The numbers of CD34+ and mononuclear (MNC) cells infused were similar in each group. Only minor differences regarding the use of G-CSF could be inferred from the analysis of the data. Faster granulocyte engraftment was evident in the treated group (mean of 10 vs 12 days to achieve >0.5 x 109/l granulocytes, P = 0.0008), without differences in incidence and severity of infections, days of fever or duration of antibiotic treatment between groups. There was slightly slower platelet engraftment (mean of 15 days in the group with G-CSF vs 12 days in the other group to achieve >20 x 109/l platelets, P = NS) in this series, but there were no differences in incidence and severity of haemorrhage or platelet transfusion support. Considering the economical costs, the median expenditure per inpatient stay was Eur5961 (range Eur4386-Eur17186) in the G-CSF group compared with Eur5751 (range Eur3676-Eur15640) in the control group (P = 0.47). From our data it could be concluded that for adult patients transplanted with PBSC there is no clear beneficial impact of post-infusion G-CSF administration.

Translation elongation factor 2 is encoded by a single essential gene in Candida albicans.

Translation elongation factor 2 (eEF2) is a large protein of more than 800 amino acids which establishes complex interactions with the ribosome in order to catalyze the conformational changes needed for translation elongation. Unlike other yeasts, the pathogenic fungus Candida albicans was found to have a single gene encoding this factor per haploid genome, located on chromosome 2. Expression of this locus is essential for vegetative growth, as evidenced by placing it under the control of a repressible promoter. This C. albicans gene, named EFT2, was cloned and sequenced (EMBL accession number Y09664). Genomic and cDNA sequence analysis identified common transcription initiation and termination signals and an 842 amino acid open reading frame (ORF), which is interrupted by a single intron. Despite some genetic differences, CaEFT2 was capable of complementing a Saccharomyces cerevisiae Deltaeft1 Deltaeft2 null mutant, which lacks endogenous eEF2, indicating that CaEFT2 can be expressed from its own promoter and its intron can be correctly spliced in S. cerevisiae.

Serum Ferritin as Risk Factor for Veno-occlusive Disease of the Liver. Prospective Cohort Study.

Veno-occlusive disease of the liver (VOD) is an important complication in hematological transplantation. The aim of this study is to analyze the risk factors for VOD and other forms of liver toxicity in a cohort of 180 peripheral stem cell transplants performed in our Center. We find that elevated pretransplant levels of serum ferritin are the most important risk marker for VOD. We believe that ferritin reflects damage induced by oxygen radicals resulting from iron-mediated catalysis. We also discuss different risk factors for VOD and other forms of liver toxicity, suggesting diferent pathogenic mechanisms.

Translation elongation factor 2 is part of the target for a new family of antifungals.

Translation elongation factor 2 (EF2), which in Saccharomyces cerevisiae is expressed from the EFT1 and EFT2 genes, has been found to be targeted by a new family of highly specific antifungal compounds derived from the natural product sordarin. Two complementation groups of mutants resistant to the semisynthetic sordarin derivative GM193663 were found. The major one (21 members) consisted of isolates with mutations on EFT2. The minor one (four isolates) is currently being characterized but it is already known that resistance in this group is not due to mutations on EFT1, pointing to the complex structure of the functional target for these compounds. Mutations on EF2 clustered, forming a possible drug binding pocket on a three-dimensional model of EF2, and mutant cell extracts lost the capacity to bind to the inhibitors. This new family of antifungals holds the promise to be a much needed and potent addition to current antimicrobial treatments, as well as a useful tool for dissection of the elongation process in ribosomal protein synthesis.

Ribosomal P-protein stalk function is targeted by sordarin antifungals.

Sordarin derivatives are remarkably selective inhibitors of fungal protein synthesis. Available evidence points to a binding site for these inhibitors on elongation factor 2, but high affinity binding requires the presence of ribosomes. The gene mutated in one of the two isolated complementation groups of Saccharomyces cerevisiae mutants resistant to the sordarin derivative GM193663 has now been identified. It is RPP0, encoding the essential protein of the large ribosomal subunit stalk rpP0. Resistant mutants are found to retain most of the binding capacity for the drug, indicating that mutations in rpP0 endow the ribosome with the capacity to perform translation elongation in the presence of the inhibitor. Other proteins of the ribosomal stalk influence the expression of resistance, pointing to a wealth of interactions between stalk components and elongation factors. The involvement of multiple elements of the translation machinery in the mode of action of sordarin antifungals may explain the large selectivity of these compounds, even though the individual target components are highly conserved proteins.

Hematopoietic cell transplantation using plasma and DMSO without HES, with non-programmed freezing by immersion in a methanol bath: results in 213 cases.

A simplified cryopreservation method for bone marrow (BM) and peripheral blood progenitor cells (PBPC) was utilized in hematopoietic cell transplantation of 213 patients with hematological or solid neoplasms after ablative chemotherapy (187 with peripheral blood progenitor cells and 26 with bone marrow). Cells were cryopreserved, after addition of autologous fresh plasma with DMSO, without HES, by freezing to -80 degrees C in a methanol bath and non-programmed freezer. For the patients autotransplanted with PBPC, the median period necessary for recovery of more than 0.5 x 10(9)/l granulocytes was 11 days (range 6-44), and 15 (8-204) days were required to obtain more than 20 x 10(9)/l platelets. For the patients autotransplanted with BM, the median period necessary to recover >0.5 x 10(9)/l granulocytes was 12 days (range 9-33), and 24 (12-57) days to obtain more than 20 x 10(9)/l platelets. These results support this method as being very effective in achieving high-quality cryopreservation. The procedure, which uses a non-programmed freezer, simplifies and reduces enormously the cost of the technical measures currently in use, enabling its adoption in almost any clinical oncological institution.

[Nutritional support in bone marrow transplantation]. / Soporte nutricional en trasplante de médula ósea.

UNLABELLED: Bone marrow transplant (BMT) implies the treatment with substances which may compromise the nutritional condition, thus increasing the morbido-mortality of these patients. The objective of this study is to evaluate the efficacy of the nutritional support (NS) protocol for patients subjected to a BMT in our center. PATIENTS AND METHODS: 55 patients were included (24 men and 31 women), who were subjected to BMT during 1994, with prior chemotherapy depending on the underlying disease. The nutritional condition (NC) was evaluated upon initiation and at the end of the NS, using anthropometric, biochemical, and immunological parameters. The NS was given by total parenteral nutrition (TPN), adapted to the needs, as of the second post-transplant day, until such time that oral nutrition was sufficient to supply the nutritional needs of the patients; oral ingestion was permitted at all times, according to the possibilities of the patient. For the statistical analysis, we used the Student's t test, Pearson's Chi squared test, and Spearman's test, with differences being considered significant for values < 0.05. RESULTS: The average duration of the TPN was 16 +/- 6 days, with a significantly longer time (p < 0.05) in patients with leukemia. The NC assessment was no different at the beginning and at the end of the NS, although all groups show a drop in the albumin levels at the end with respect to those at the beginning, with this being statistically significant in patients with leukemia (p < 0.05), and with solid tumors (p < 0.01), 14.5% of the patients maintained an acceptable oral ingestion (with 75% having lymphomas), and 34.5% did not show any associated oral ingestion. Te better albumin maintenance was correlated with acceptable oral ingestion (p < 0.05). CONCLUSIONS: Nutritional support of patients subjected to a BMT is effective for maintaining their NC levels. The longest duration of the TPN, the lowest frequency of associated oral ingestion, and the greatest decrease of the serum albumin, levels are seen in those cases which had the most aggressive chemotherapy prior to the BMT, which requires adaptation of the NS in function of the underlying disease. The association of oral ingestion may be beneficial due to its effect on the gastrointestinal tract.

Single-centre experience of peripheral blood stem cell transplantation using cryopreservation by immersion in a methanol bath.

A simplified method to remove and cryopreserve peripheral blood stem cells (PBSC) was utilised to restore the bone marrow in 31 patients with haematological or solid neoplasms after ablative chemotherapy. Mobilization was performed with subcutaneous G-CSF, starting 4 days before the first PBSC harvest and continuing to the last day of harvest. Cryopreservation was carried out by freezing cells to -80 degrees C after addition of autologous fresh plasma with DMSO, in a methanol bath and non-programmed freezer. The PBSC were reinfused in all cases. The mean quantity of CD34 cell (x 10(6)/kg) infused was 6.5 +/- 6.7. The mean number of procedures needed to harvest an appropriate number of PBSC was 3.6 +/- 1.3. The mean times necessary to recover more than 0.5 x 10(9)/l granulocytes were 11 +/- 4 (8-30) days and 23 +/- 13 (8-55) days to obtain more than 20 x 10(9)/l platelets. These results confirm our method as very effective in achieving a high-quality harvest, and it was used in paediatric and adult patients without problems. This procedure, using a non-programmed freezer, simplifies and reduces enormously the cost of the technical measures currently used, enabling their adoption in almost any clinical oncological institution.

PIK1, an essential phosphatidylinositol 4-kinase associated with the yeast nucleus.

Transmission of mitogenic and developmental signals to intracellular targets is often mediated by inositol derivatives. Here we present the cloning and characterization of a gene from Saccharomyces cerevisiae, PIK1, encoding the enzyme that catalyses the first committed step in the production of the second messenger inositol-1,4,5-trisphosphate. PIK1 encodes a phosphatidylinositol 4-kinase (PI 4-kinase) essential for growth. Cells carrying PIK1 on a multicopy vector overexpress PI 4-kinase activity exclusively in a nuclear fraction, suggesting that PIK1 is part of a nuclear phosphoinositide cycle. Temperature-sensitive mutations, but not a null mutation, can be suppressed by high osmolarity or an elevated concentration of Ca2+. Conditional mutants have a cytokinesis defect as indicated by a uniform terminal phenotype of cells with large buds and fully divided nuclei. We suggest that PIK1 controls cytokinesis through the actin cytoskeleton.

Nuclear import substrates compete for a limited number of binding sites. Evidence for different classes of yeast nuclear import receptors.

A nuclear receptor likely involved in nuclear protein import is described. Purified ATP-depleted yeast nuclei show saturable high-affinity binding of the yeast nuclear protein Mcm1. The dissociation constant for the binding is 0.5 microM, and the number of binding sites is approximately 3,500 per nucleus, equivalent to 10-30 binding sites per nuclear pore. Mcm1 competes with other yeast nuclear proteins Ste12 and Swi5, but not with Rap1 or Nop1, indicating that there may be different types of import receptors. Bound Mcm1 is resistant to extraction by nucleases, salt, and non-ionic detergent, but can be released by 5 M urea, suggesting that Mcm1 binds to a yeast equivalent of the nuclear pore complex-lamina fraction of higher eukaryotes.