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BACKGROUND: Hematopoietic stem cell transplantation (HSCT) remains the most efficacious therapy in patients with acute leukemia. For older patients and those lacking a related HLA-compatible donor, autologous transplantation (auto-HSCT) is a valid alternative therapeutic option. METHODS: From 1997 until 2014 in the Department of Hematooncology and Bone Marrow Transplantation, Medical University of Lublin, Poland, 29 auto-HSCT were performed in patients with acute myeloid leukemia (AML; 15 men and 14 women; median age, 52.2 years). The following FAB types of AML were diagnosed: M0, 3; M1, 4; M2, 6; M4, 10; and M5, 6. Patients with AML were classified into 3 cytogenetic prognostic groups: high risk, 9; intermediate risk, 16; and low risk, 4. Twenty-five were in first complete remission and 4 in second complete remission. The peripheral HSCs mobilized after chemotherapy (mainly second course of consolidation) and granulocyte colony-stimulating factor were the source of the stem cells in all cases. The median number of infused CD34+ cells was 3.58 × 10(6)/kg. The conditioning regimen was busulfan and cyclophosphamide in all patients with AML. The intravenous form of busulfan was applied in the last 15 patients. RESULTS: The median time for absolute neutrophil count recovery >0.5 × 10(9)/L and for platelet count >20.0 × 10(9)/L was 12 and 16.5 days, respectively. Treatment-related mortality rate in the whole group was 3.4% (1 patient with sepsis in the aplastic period). The median follow-up time of survivors was 21.9 months (range, 11.7-142.4). The 3-year projected disease-free survival and overall survival rates were 60% and 68%, respectively. CONCLUSIONS: Our data confirm that auto-HSCT is a valuable therapeutic option for patients with AML, especially older patients and those lacking related HLA-compatible donors.

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BACKGROUND: Autologous peripheral blood stem cell transplantation (APBSCT) is the standard of therapy for patients with multiple myeloma and refractory Hodgkin's and non-Hodgkin's lymphomas. Granulocyte colony-stimulating factor (G-CSF) is widely used to accelerate hematopoietic recovery after transplantation and to reduce the morbidity and mortality associated with prolonged neutropenia. Biosimilar G-CSF is approved for the same indications as the originator G-CSF. This is one of the first reported uses of a biosimilar G-CSF for neutrophil recovery after APBSCT. METHODS: A total of 23 consecutive patients with hematological malignancy (multiple myeloma, Hodgkin's and non-Hodgkin's lymphomas, and acute myelogenous leukemia) were recruited at the Department of Haematooncology and Bone Marrow Transplantation at the Medical University of Lublin. Patients (12 men and 11 women; median age, 47 ± 13 years) received biosimilar G-CSF (Zarzio, Sandoz Biopharmaceuticals) after myeloablative chemotherapy (primarily BiCnU, etoposide, cytarabine, and melphalan or melphalan 140/200 mg/m(2)) followed by PBSCT. The median number of transplanted CD34+ cells was 4.2 ± 0.8 × 10(6)/kg body wt. G-CSF therapy was started when absolute neutrophil count (ANC) was <0.5 × 10(9)/L and was continued until ANC reached >1.5 × 10(9)/L for 3 consecutive days. Hematopoietic recovery parameters were compared with those in the control group, which consisted of 23 consecutive patients transplanted in the period before the biosimilar G-CSF group and receiving originator G-CSF (Neupogen, Amgen). RESULTS: The mean duration of treatment with biosimilar and originator G-CSF was 14.4 ± 5.1 and 18.6 ± 11.5 days, respectively (P = .43). The adverse event profile was comparable between the biosimilar G-CSF and originator G-CSF groups, with similar occurrence of neutropenic fever (5 versus 6 patients) and bone pain (7 patients in each group). One patient in the biosimilar group had neutropenic enterocolitis and sepsis. There was no case of death in either group. Granulocyte recovery in the study group was as follows: mean days to ANC >0.5 × 10(9)/L was 13.0 ± 4.0 days; to ANC >1.5 × 10(9)/L, 13.6 ± 4.5 days; and to ANC >1.5 × 10(9)/L, 14.0 ± 4.7 days. Mean duration until platelet recovery >20 × 10(9)/L was 16.1 ± 4.4 days. There were no statistically significant differences between the biosimilar and originator G-CSF groups in hematopoietic recovery parameters. CONCLUSIONS: Biosimilar G-CSF is safe and effective in reducing the duration of neutropenia in patients undergoing myeloablative therapy followed by APBSCT and probably in cost savings in transplantation budgets.

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Agaricus bisporus (Lange) Imbach mushrooms, which are cultivated commercially under environmentally controlled conditions, are the most valuable crop in Pennsylvania. In August 2011, we first observed a mucoraceous mold colonizing primordia and mature basidiocarps of a new brown portabella strain of A. bisporus at two commercial mushroom farms in Chester County, PA. This strain is a hybrid between a commercial strain producing white basidiocarps and a brown wild type isolate of A. bisporus. Mushrooms mature in weekly "flushes". By third flush, 25% of the production surface at both farms was colonized by a fast growing mycelium that was initially white, subsequently yellow to golden brown, and finally grayish. Mushrooms colonized by the mold showed pitting, discoloration, and necrosis. Two pure cultures of the mold were obtained by the hyphal tip method from mature, necrotic basidiocarps at each farm. These isolates were accessioned in the ARS Culture Collection (NRRL, Peoria, IL) as NRRL 54814 to 54815 and 54818 to 54819. The cultures produced abundant aerial sporangiophores that branched dichotomously on potato dextrose agar. Light microscopic examination revealed that each branch terminated in a globose, multispored sporangium with a conspicuous columella. Individual cultures of NRRL 54818 and 54819 produced large (175 to 250 × 200 to 250 µm), barrel-shaped, dark brown to black zygosporangia between opposed suspensors, indicating they were homothallic. Morphological and cultural characteristics of the mold matched the description of Syzygites megalocarpus (3), a member of the Mucorales reported to colonize diverse, mostly fleshy basidiomycetes (2), including cultivated matsutake (Tricholoma matsutake) in Korea (1). Molecular phylogenetic confirmation of the morphological identification was obtained by PCR amplifying and sequencing domains D1 and D2 at the 5' end of the nuclear ribosomal large subunit (LSU rDNA). The four isolates shared an identical LSU rDNA allele. A search of the NCBI nucleotide database, using a partial LSU rDNA sequence from NRRL 54814 as the BLAST query, revealed that it shared 99.5% identity with AF157216.1, a reference isolate of S. megalocarpus NRRL 6288 (3). To assess whether cultures of S. megalocarpus could induce the disease, caps of portabella and white button mushrooms were inoculated with 3.7 × 106 sporangiospores. When incubated in moist chambers at 21 to 22°C with a 12-h photoperiod, disease symptoms developed in 2 to 3 days on portabella that included discoloration and pitting at the site of inoculation. S. megalocarpus was reisolated from the symptomatic mushrooms and produced a colony identical to the original. By comparison, white button mushrooms inoculated with S. megalocarpus, using the same method, only showed minor pitting and discoloration. Disease symptoms were not observed on mushrooms inoculated with water as a negative control. Although development of new commercial varieties derived using "wild" genetically diverse stocks is an effective way to introduce desirable traits into cultivated mushrooms, it carries the risk of introducing new diseases into the industry. References: (1) K.-H. Ka et al. Korean J. Mycology 27:345, 1999. (2) R. L. Kovacs and W. J. Sundberg. Trans. Il. State Acad. Sci. 92:181, 1999. (3) K. O'Donnell. Zygomycetes in culture. Palfrey Contributions in Botany. No. 2. Department of Botany, University of Georgia, Athens, 1979.

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Purine nucleoside analogues, cladribine (2-chlorodeoxyadenosine, 2-CdA) and fludarabine (FAMP) are active agents in acute myeloid leukemias (AMLs). Synergistic interaction between FAMP or 2-CdA with cytarabine (cytosine arabinoside, Ara-C) has been demonstrated in preclinical and clinical studies. The current multicenter phase II study was initiated to evaluate the efficacy and toxicity of induction treatment consisting of 2-CdA (5 mg/m2), Ara-C (2 g/m2), mitoxantrone (MIT, 10 mg/m2) and granulocyte colony-stimulating factor (G-CSF) (CLAG-M) in refractory AML. In case of partial remission, a second CLAG-M was administered. Patients in complete remission (CR) received consolidation courses based on high-dose Ara-C and MIT with or without 2-CdA. Forty-three patients from five centers were registered: 25 primary resistant and 18 relapsed. CR was achieved in 21 (49%) patients, 20 (47%) were refractory and 2 (5%) died early. Hematologic toxicity was the most prominent toxicity of this regimen. The overall survival (OS; 1 year) for the 42 patients as a whole and the 20 patients in CR were 43% and 73%, respectively. Disease-free survival (1 year) was 68.6%. None of the analyzed prognostic factors influenced the CR and OS probability significantly. We conclude that CLAG-M regimen has significant antileukemia activity in refractory AML, which seems to be better than the activity of many other regimens. The toxicity of the treatment is acceptable.

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BACKGROUND: The previous study by the Polish Adult Leukemia Group has demonstrated that addition of cladribine to standard DNR+AraC induction potentiates the antileukemic activity. The goal of this study was to compare the efficacy of bone marrow or peripheral blood hematopoietic cell collection in patients who obtained remission after daunorubicine plus cytarabine induction with cladribine (DAC-7) or without addition of cladribine (DA-7) in preparation for autotransplantation. PATIENTS AND METHODS: Sixty-six patients aged 41 years (range, 17-58 years) were included in this study: 33 cases in the DAC-7 and 33 in the DA-7 arm. Hematopoietic cells were collected from the bone marrow (ABMT, n = 29) or from the peripheral blood (ABCT, n = 37) using cytopheresis after administration of AraC (2 x 2 g/m2) on days 1, 3, 5 and subsequent G-CSF (10 microg/kg) from day 7 as mobilization therapy. RESULTS: The numbers of harvested CD34+ cells were similar in the DAC-7 and DA-7 pretreated patients both after harvesting from peripheral blood (2.55 x 10(6)/kg vs 2.5 x 10(6)/kg) and from bone marrow (1.62 x 10(6)/kg vs 1.55 x 10(6)/kg), respectively. The proportion of patients with sufficient material for autologous bone marrow transplantation was higher in the DAC-7 compared with the DA-7 arm. All patients engrafted; hematopoietic recovery was similar in both subgroups. CONCLUSION: Addition of cladribine to a standard DA induction does not impair the harvesting of hematopoietic cells and their engraftment after autotransplantation.

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BACKGROUND: The reported probability of survival of patients with Hodgkin's disease (HD) following high-dose chemotherapy with autologous stem cell transplantation (HDC/ASCT) is 35-65% at 5 years. The Polish Lymphoma Research Group investigated retrospectively prognostic factors for overall survival (OS) and event-free survival (EFS), and the risk of secondary malignancies in a large series of patients who underwent HDC/ASCT. PATIENTS AND METHODS: The data of 341 consecutive patients treated in 10 centers from 1990 to 2002 were collected and analyzed. RESULTS: The actuarial 5-year OS and EFS were 64% [95% confidence interval (CI) 57% to 71%] and 45% (95% CI 39% to 51%), respectively. In the multivariate model, unfavorable prognostic factors for EFS were less than partial response at the time of ASCT [relative risk (RR), 2.92 (95% CI 1.68-5.08); P<0.001] and three or more previous chemotherapy lines (RR, 2.16; 95% CI 1.42-3.30; P<0.001). These two factors were also associated with unfavorable OS (RR, 3.32; 95% CI 1.90-5.79; P<0.001 and RR, 2.34, 95% CI 1.51-3.64; P<0.001). Five-year cumulative risk of secondary malignancy was 8.4% (95% CI 2% to 13%) and the only identified risk factor was splenectomy (P=0.02). CONCLUSIONS: HDC/ASCT should be considered early in the course of disease for patients with a response after standard therapy.

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We analysed the treatment outcome of primary refractory HD patients managed with high-dose chemotherapy and haematopoietic cell transplantation. Data of 65 adult patients who underwent HDC/ASCT in nine Polish centres for primary resistant Hodgkin's disease between June 1991 and July 2000 were collected retrospectively. Response rate to HDC/ASC: CR, 54%; PR, 20%; less than PR, 15%; early deaths, 11%. Actuarial 3-year OS and PFS were 55% and 36%, respectively. In multivariate analysis, lack of bulky lymph nodes and use of immunotherapy were favourable factors for both OS and PFS. IPF <3 at the time of transplantation was predictive for PFS. However, the prognostic impact of immunotherapy should be interpreted with caution since this group included more patients who achieved CR after HDC/ASCT. The results of HDC/ASCT are encouraging and confirm earlier findings. The role of immunotherapy should be further investigated in prospective trials.

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The biosynthesis of the thaxtomin cyclic dipeptide phytotoxins proceeds nonribosomally via the thiotemplate mechanism. Acyladenylation, thioesterification, N-methylation, and cyclization of two amino acid substrates are catalyzed by the txtAB-encoded thaxtomin synthetase. Nucleotide sequence analysis of the region 3' of txtAB in Streptomyces acidiscabies 84.104 identified an open reading frame (ORF) encoding a homolog of the P450 monooxygenase gene family. It was proposed that thaxtomin A phenylalanyl hydroxylation was catalyzed by the monooxygenase homolog. The ORF was mutated in S. acidiscabies 84.104 by using an integrative gene disruption construct, and culture filtrate extracts of the mutant were assayed for the presence of dehydroxy derivatives of thaxtomin A. Reversed-phase high-performance liquid chromatography (HPLC) and HPLC-mass spectrometry indicated that the major component in culture filtrate extracts of the mutant was less polar and smaller than thaxtomin A. Comparisons of electrospray mass spectra as well as (1)H- and (13)C-nuclear magnetic resonance spectra of the purified compound with those previously reported for thaxtomins confirmed the structure of the compound as 12,15-N-dimethylcyclo-(L-4-nitrotryptophyl-L-phenylalanyl), the didehydroxy analog of thaxtomin A. The ORF, designated txtC, was cloned and the recombinant six-His-tagged fusion protein produced in Escherichia coli and purified from cell extracts. TxtC produced in E. coli exhibited spectral properties similar to those of cytochrome P450-type hemoproteins that have undergone conversion to the catalytically inactive P420 form. Based on these properties and the high similarity of TxtC to other well-characterized P450 enzymes, we conclude that txtC encodes a cytochrome P450-type monooxygenase required for postcyclization hydroxylation of the cyclic dipeptide.

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Intravascular lymphoma (IVL) is a rare aggressive disease characterised by the presence of lymphoma cells only in the lumina of small vessels, particularly capillaries. Only about 200 cases have been reported in the world (some of them retrospectively). IVL is predominantly of B-cell lineage origin but occasionally T-cell lineage occurs. Multiple organs may be involved and a variety of clinical presentations have been described. These include nephrotic syndrome, pyrexia and hypertension, breathlessness and haemolytic anaemia, leukopoenia, pancytopoenia and disseminated intravascular coagulation. We report a case of a 38-year-old woman with a highly aggressive clinical course of IVL. She was admitted to the Department of Neurosurgery because of spondylolisthesis of L5-S1 qualified to surgery. During hospitalisation haemolytic anaemia, thrombocytopoenia and splenomegaly were observed and she was admitted to the Department of Haematology for diagnosis. During her staying in the hospital, new symptoms, such as kidney and liver failure, occurred and the central nervous system was involved. The clinical course was very rapid and progressive. Corticosteroid therapy was started but the disease soon led to the fatal outcome. Diagnosis was established at post-mortem examination.

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Four Streptomyces species have been described as the causal agents of scab disease, which affects economically important root and tuber crops worldwide. These species produce a family of cyclic dipeptides, the thaxtomins, which alone mimic disease symptomatology. Structural considerations suggest that thaxtomins are synthesized non-ribosomally. Degenerate oligonucleotide primers were used to amplify conserved portions of the acyladenylation module of peptide synthetase genes from genomic DNA of representatives of the four species. Pairwise Southern hybridizations identified a peptide synthetase acyladenylation module conserved among three species. The complete nucleotide sequences of two peptide synthetase genes (txtAB) were determined from S. acidiscabies 84.104 cosmid library clones. The organization of the deduced TxtA and TxtB peptide synthetase catalytic domains is consistent with the formation of N-methylated cyclic dipeptides such as thaxtomins. Based on high-performance liquid chromatography (HPLC) analysis, thaxtomin A production was abolished in txtA gene disruption mutants. Although the growth and morphological characteristics of the mutants were identical to those of the parent strain, txtA mutants were avirulent on potato tubers. Moreover, introduction of the thaxtomin synthetase cosmid into a txtA mutant restored both pathogenicity and thaxtomin A production, demonstrating a critical role for thaxtomins in pathogenesis.

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Atherosclerotic plaque vulnerability is suggested to be determined by its chemical composition. However, at present there are no in vivo techniques available that can adequately type atherosclerotic plaques in terms of chemical composition. Previous in vitro experiments have shown that Raman spectroscopy can provide such information in great detail. Here we present the results of in vitro and in vivo intravascular Raman spectroscopic experiments, in which dedicated, miniaturized fiber-optic probes were used to illuminate the blood vessel wall and to collect Raman scattered light. The results make clear that an important hurdle to clinical application of Raman spectroscopy in atherosclerosis has been overcome, namely, the ability to obtain in vivo intravascular Raman spectra of high quality. Of equal importance is the finding that the in vivo intravascular Raman signal obtained from a blood vessel is a simple summation of signal contributions of the blood vessel wall and of blood. It means that detailed information about the chemical composition of a blood vessel wall can be obtained by adapting a multiple least-squares fitting method, which was developed previously for the analysis of in vitro spectra, to account for signal contributions of blood.

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Intravascular lymphoma (IVL) is characterized by proliferation of large malignant lymphoid cells within the lumen of small vessels. Sites usually affected include the central nervous system and skin although involvement of multiple organ symptoms have been described. IVL is very rare and aggressive type of lymphoma. Based on review of the literature we present clinicopathological, immunohistochemical and molecular features of the IVL. The etiological possibilities are discussed.

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We describe 4 cases of non-Hodkin's lymphomas that were interesting because of their curiosal clinical courses and spontaneous complete remissions during the course of high malignancy lymphoma. We present three of them for the first time in Poland. Case 1: a 61-year old woman was admitted to the hospital because of the headache, lasting for 4 months before hospitalization and right hemiparesis. CT scans revealed the presence of tumor in the temporo-occipital region. The diagnosis of B-cell lymphoma was established at histopathological examination of the postoperative material. Co60--therapy of these region was applied after the operation with good response. Case 2: a 38-year woman was admitted to the hospital because of L5-S1 spondylolisthesis to operate it. During the hospitalization haemolytic anaemia of unknown origin, thrombocytopoenia, splenomegaly, fever and rising acute insufficiency of kidneys, heart, liver and CNS were occurred. The patient died, despite applying corticosteroidotherapy. The diagnosis of intravascular lymphoma was established at postmortem examination. Case 3: a 51-year old woman was admitted to the hospital with diagnosis: anaplastic non-Hodgkin lymphoma B-cell type high malignancy established after the double histopathological examination of lymph nodes and biopsy of the lung. At the admission to the Department of Haematology we stated absolute regression of these changes. The patient had been only observed in the Outpatient Department over 1 year. She died after 6 months since the beginning of the relapse despite intensive chemotherapy. Case 4: a 43-year old man was admitted to the hospital because of great hyperleukocytosis, hepatosplenomegaly and neurological symptoms. The diagnosis: chronic prolymphocytic leukaemia was established. The cerebrospinal fluid examination showed presence of mononuclears which infiltrated CNS. CT scans of the brain revealed leucaemic infiltrations of the hemispheres and cerebellum. The patient died despite intensive therapy due to rising progressive multiorgan failure.

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This study was designed to investigate the immunostimulatory effect of low dose Il-2 treatment in B-CLL patients previously treated with 2-chlorodeoxyadenosine (2CdA) in whom severe depletion of T lymphocyte subsets was observed. Four patients enrolled into the study had previously been treated with 3-6 courses of 2CdA. All patients suffered from recurrent infections and showed CD4+ and CD8+ immunosuppression. Recombinant Il-2 was given subcutaneously at a dose of 100 micrograms (1.8 x 10(6)IU) daily for 6 weeks. The drug was administered between 2CdA courses. These preliminary studies showed a marked increase in T cell subsets after Il-2 treatment. All patients displayed an increase of NK cells and there was increased expression of Il-2 receptors (CD 25 and CD 122) on lymphocytes. It is possible that the combination of cytotoxic therapy with 2CdA and low dose rIl-2 could stimulate the T-cell immune system and may be a promising regimen in patients with B-CLL with severe depletion in T-cell subsets.

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Recent studies have been carried out to delineate further the role of the Rb1 gene in B-cell chronic lymphocytic leukaemia (B-CLL). The suggested role of the Rb1 gene in this disease was based on cytogenetic data. CLL patients (40 in toto) were examined using cytogenetic and molecular biological methods. R-banding analysis of metaphase chromosomes revealed aberrations in only seven cases containing either the Rb1 gene or a chromosome 13 monosomy. No evident differences were found by RT-PCR analysis of Rb1 gene expression. The amounts of the RT-PCR products obtained appeared to be approximately equal in all cases, and was independent of the clinical stage, immunophenotypes and LPS or TPA stimulation.

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A comparative research on lymphocyte immunological phenotypes in peripheral blood and bone marrow was carried out on 14 patients with B-cell chronic lymphocytic leukaemia. Three types of B cell markers were estimated: 1-light chains (lambda or kappa) on the surface of cells, 2-CD5 antigen, 3-capability of forming mouse erythrocyte rosettes (MER); the last two markers are mostly characteristic of leukaemic cells. The patients were divided into 3 groups according to the localisation of the main mass of tumorous cells: group I-the patients, whose clinical picture was dominated by the infiltration of lymphoid structures of the abdominal cavity and/or with massive infiltration of peripheral lymph nodes; group II-the patients, whose clinical picture was dominated by the infiltration of bone marrow; group III-the intermediate-patients with large mass of tumor in lymphoid structures and with bone marrow insufficiency symptoms. In most of the patients of group I, the percentage of CD5+ cells in peripheral blood was higher than the one in bone marrow (arithmetic means were 38.5% for blood and 26.7% for marrow). It was the reverse in group II (the means were 44.8% for blood and 64.3% for marrow, P < 0.01). The percentage in group III was similar to that of group I (the means-48% for blood and 29.25% for marrow). No correlation between the percentage of CD5+ and MER+ cells was found in respective groups of the patients although the last marker behaved similarly to CD5. The results obtained suggest that while estimating percentages of CD5+ cells in peripheral blood and bone marrow, one can differentiate between chronic lymphocytic leukaemia (with domination of CD5+ cells in bone marrow) and leukaemic phase of small lymphocyte lymphoma (with domination of CD5+ cells in peripheral blood).

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The expression of surface immunoglobulins (SIg) on peripheral blood, bone marrow, and lymph node lymphocytes was studied in a group of 10 patients with B cell chronic lymphocytic leukaemia. In 4 patients differences in the SIg phenotypes were found when cells from blood, bone marrow and lymph nodes were examined. Peripheral blood lymphocytes were characterized as a monoclonal B cell population whereas in the marrow or lymph node lymphocytes a tendency toward poly-clonality was found. We suggest that these differences reflect the origin of the initial leukaemic transformation: intra versus extra-medullar. In case of intramedullary origin of leukaemia the transformed clone infiltrates subsequently lymph nodes or other lymphoid structures. In leukaemia of extra-medullar origin the bone marrow is infiltrated later and therefore the tendency toward polyclonal SIg picture of the bone marrow lymphocytes contrasts with the monoclonality of the peripheral blood cells.

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Lipopolysaccharide (LPS) and phorbol esters (TPA) stimulate lymphocytes proliferation in two different ways. While LPS primary function is specific receptor binding, TPA directly activate cellular protein kinase C. The stimulation of human leukaemic lymphocytes (from chronic lymphocytic leukaemia patients) with LPS and TPA results in two different types of response: to both stimulators, and to LPS only. Therefore the supposed defect of cellular receptors can not explain all the observed effects. The existence of TPA independent second messengers and changes in signal transduction pathways downstream of PKC can be considered.

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We present an unusual case of the myelodysplastic syndrome (subtype refractory anemia with the excess of blasts in transformation--RAEB-t) associated with significant increase of IgG (4,700 mg/dl), lambda (160 U/dl) in blood serum and circulating clone of B lymphocytes SIgG, lambda, manifesting clonal rearrangement of JH domain. Peripheral blood cells of the patient showed two different chromosomal abnormalities: 47,XY, + del/8/p? and 47,XY, +22, +14, -19. We suppose that two independent neoplastic clones are developed in the described case, i.e. a population displaying markers of myeloblasts and monoblasts, and a clone of B lymphocytes.

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Single 10-bp primers were used to generate random amplified polymorphic DNA (RAPD) markers from commercial and wild strains of the cultivated mushroom Agaricus bisporus via the polymerase chain reaction. Of 20 primers tested, 19 amplified A. bisporus DNA, each producing 5 to 15 scorable markers ranging from 0.5 to 3.0 kbp. RAPD markers identified seven distinct genotypes among eight heterokaryotic strains; two of the commercial strains were shown to be related to each other through single-spore descent. Homokaryons recovered from protoplast regenerants of heterokaryotic strains carried a subset of the RAPD markers found in the heterokaryon, and both of the haploid nuclei from two heterokaryons were distinguishable. RAPD markers also served to verify the creation of a hybrid heterokaryon and to analyze meiotic progeny from this new strain: most of the basidiospores displayed RAPD fingerprints identical to that of the parental heterokaryon, although a few selected slow growers were homoallelic at a number of loci that were heteroallelic in the parent, suggesting that they represented rare homokaryotic basidiospores; crossover events between a RAPD marker locus and its respective centromere appeared to be infrequent. These results demonstrate that RAPD markers provide an efficient alternative for strain fingerprinting and a versatile tool for genetic studies and manipulations of A. bisporus.

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