Novel cost effective full scale mussel shell bioreactors for metal removal and acid neutralization.

Acid mine drainage (AMD) impacted waters are a worldwide concern for the mining industry and countries dealing with this issue; both active and passive technologies are employed for the treatment of such waters. Mussel shell bioreactors (MSB) represent a passive technology that utilizes waste from the shellfish industry as a novel substrate. The aim of this study is to provide insight into the biogeochemical dynamics of a novel full scale MSB for AMD treatment. A combination of water quality data, targeted geochemical extractions, and metagenomic analyses were used to evaluate MSB performance. The MSB raised the effluent pH from 3.4 to 8.3 while removing up to ∼99% of the dissolved Al, and Fe and >90% Ni, Tl, and Zn. A geochemical gradient was observed progressing from oxidized to reduced conditions with depth. The redox conditions helped define the microbial consortium that consists of a specialized niche of organisms that influence elemental cycling (i.e. complex Fe and S cycling). MSB technology represents an economic and effective means of full scale, passive AMD treatment that is an attractive alternative for developing economies due to its low cost and ease of implementation.

Deregulation of BCL6 in non-Hodgkin lymphoma by insertion of IGH sequences in complex translocations involving band 3q27.

Chromosomal band 3q27 frequently engages in translocations with a number of sites within the genome, including those containing IG and other genes, during the development of B-cell lymphoma. The BCL6 gene, mapped at 3q27, is deregulated in these translocations and was isolated from a t(3;14)(q27;q32) translocation. It encodes a zinc-finger transcription repressor protein, which is expressed mainly in the germinal center (GC) B cells and plays a key role in GC development and T-cell-dependent immune response. BCL6 deregulation in 3q27 translocations is brought about by substitution of its 5' regulatory sequences by promoters of the rearranging genes. BCL6-rearranging genes studied so far (IGH, IGLL, TTF, BOBI, H4) displayed a broader pattern of expression than BCL6 during B-cell development. This observation has led to the suggestion that continued expression of BCL6 beyond its developmentally regulated point of downregulation under the direction of substituted promoters may keep the GC B cell in a cycling mode and lead to clonal expansion and lymphoma development. However, the rearranging partners of BCL6 in several of the 3q27 translocations have not yet been identified. In a molecular cloning analysis of two such translocations, t(1;3)(q21;q27) and t(3;6)(q27;p25), and an immunoblastic lymphoma cell line, OSI-LY8, we identified a novel mechanism of BCL6 deregulation. This comprised replacement of BCL6 5' regulatory sequences by insertion of IG gene transcriptional regulatory sequences at the translocation junction. These studies demonstrate novel features of instability of 3q27, and of the BCL6 and IGH genes, in B-cell lymphomagenesis.

Involvement of BCL6 in chromosomal aberrations affecting band 3q27 in B-cell non-Hodgkin lymphoma.

Chromosomal band 3q27 exhibits recurring and nonrecurring translocations and other rearrangements in approximately 8% of B-cell non-Hodgkin lymphomas (NHL) belonging to low-grade as well as diffuse aggressive histologies. The BCL6 gene, which encodes a zinc-finger transcription repressor protein and which maps to chromosomal band 3q27, is deregulated in t(3;14)(q27;q32) and other translocations by substitution of its transcription regulatory sequences by those of genes on the partner chromosomes. To delineate the cytogenetics and investigate the nature and consequence of BCL6 involvement in the spectrum of 3q27 aberrations seen in NHL, we analyzed a panel of 53 NHL tumors with 3q27 aberrations for BCL6 gene rearrangements and a subset of 32 of these for mutations. We identified four new recurring translocations involving 3q27, in addition to the previously recognized t(3;14)(q27;q32) and its variant, t(3;22)(q27;q11). Histologically, the 3q27 breaks were represented by 4% mantle cell lymphomas, 38% follicular center cell lymphomas, and 58% diffuse large B-cell lymphomas. Approximately 50% of the tumors exhibited BCL6 rearrangements, whereas 87.5% showed mutations in the 5' noncoding region which contains the transcription regulatory sequences. These results demonstrate that a substantial proportion of cytogenetically detected 3q27 breaks in NHLs do not represent BCL6-associated translocations. They also suggest alternate breakpoints which may lead to BCL6 deregulation, or involvement of other genes in 3q27 translocations. The frequent BCL6 mutation in these tumors is consistent with our previous observation of hypermutation of the 5' noncoding region of the gene in lymphomas arising in the germinal-center B-cells.

The t(2;3)(q21;q27) translocation in non-Hodgkin's lymphoma displays BCL6 mutations in the 5' regulatory region and chromosomal breakpoints distant from the gene.

The BCL6 gene, mapped at the chromosomal band 3q27, encodes a POZ/Zinc finger transcription repressor protein. It is frequently activated in Non-Hodgkin's lymphomas (NHL) by translocations with breakpoints clustering in the 5' major breakpoint region (MBR) as well as by mutations in the same region. The translocations lead to BCL6 activation by substitution of promoters of rearranging genes derived from the reciprocal chromosomal partners such as IG. We report the molecular genetic analysis of a novel t(2;3)(q21;q27) translocation subset in NHL comprising three cases without apparent BCL6 involvement in the translocation. Southern blot analysis of tumor DNAs utilizing BCL6 MBR probes revealed no rearrangement in two cases. Two rearranged bands in the third case resulted from a deletion in one allele and a mutation in the other allele. Southern blot analysis of DNA from one of the two tumors without BCL6 rearrangement, using a probe derived from the recently identified alternative breakpoint region (ABR), showed a rearrangement. The ABR is located 200-270 kb telomeric to MBR. Mutations were identified in the previously reported hypermutable region of BCL6 in all three tumors. In one, the mutant allele alone was found to be expressed by RT-PCR analysis of RNA. These results demonstrate the presence of 3q27 translocation breakpoints at a distance from BCL6 suggesting distant breaks that deregulate the gene or involvement of other genes that may be subject to rearrangement.

Diffuse large cell lymphomas exhibit frequent deletions in 9p21-22 and 9q31-34 regions.

We have previously identified deletions of 9p and 9q in a cytogenetic analysis of a large series of non-Hodgkin's lymphomas (NHLs), which suggested loss of candidate tumor suppressor genes (TSGs). In order to define these deletions at the molecular level, we performed an LOH analysis of a panel of paired normal and tumor DNAs comprising 13 cases of diffuse lymphoma with a large cell component (DLLC) and 18 cases of Burkitt's lymphoma (BL). The loci tested comprised eight polymorphic probes mapped to 9p (D9S33, D9S25, IFNB, IFNA, IFNW, D9S126, D9S3, and D9S19) and seven polymorphic probes mapped to 9q (D9S29, ASS, AKI, ABL, D9S10, D9S7, and D9S14). In this analysis, among cases informative for all loci in each subset, 5/13 (38%) DLLC and 4/18 (22%) BL showed LOH at 9p loci, whereas 5/13 (38%) DLLC and 3/18 (16%) BL showed LOH at 9q loci. Among the 9p loci partial homozygous or heterozygous losses were observed in 20-50% of informative cases of DLLC at D9S25, IFNB, IFNA, IFNW, D9S126, and D9S3, whereas in BL, losses at these loci ranged from 0% to 11%. Among the 9q loci, heterozygous losses were observed in > 20% of informative cases of DLLC at D9S7 (23%) and D9S29 (27%), whereas no losses were seen at these two loci in BL. These data demonstrate a high level of molecular deletion in DLLC, but not in BL, suggesting that loss of one or more TSGs on chromosome 9 plays an important role in DLLC development.

Detection of canine homologs of human MYC, BCL2, IGH, and TCRB genes by Southern blot analysis.

Subsets of non-Hodgkin's lymphoma in humans have been shown to involve activation of protooncogenes such as MYC and BCL2 resulting from chromosome translocation involving the IGH and TCR genes. Malignant lymphomas in the canine present histologic and clinical subsets similar to those in humans. To study the genetic nature of these lymphomas, we undertook this study to determine, by Southern blotting analysis, the extent of homology between the human and canine genes MYC, BCL2, IGH, and TCRB using human gene probes. Our results, presented here, show that the organization of these genes in the two species is very similar.

Cytogenetic and histologic correlations in malignant lymphoma.

Although a number of studies have indicated correlations between histologic subtypes of tumors and certain nonrandom chromosome changes, cytogenetic studies of lymphoma are in an early stage compared to those of leukemia. No comprehensive analysis of available data has so far been attempted in the literature either. Here we present an analysis of chromosome changes and their correlation with subtypes of lymphoma studied by conventional histology and cell surface markers, as observed in two sets of data: a group of 65 karyotypically abnormal tumors sequentially ascertained and studied by us during the period January 1, 1984 to April 30, 1985, and a larger data set derived by combining our data with those from two published series from the University of Minnesota that are comparable to our data. These combined data, which comprise the largest data set on the cytogenetics of lymphomas assembled so far, enabled a comprehensive analysis of correlation between chromosome change and tumor histology and the patterns of chromosome instability in these tumors. We found several significant associations, some previously described and others now recognized, between nonrandom chromosome gains, breaks, translocations, and deletions and histologic subtypes of tumors that characterize lymphomas. The data indicate that finding of chromosome breaks at certain sites (eg, 8q24, 14q32, 18q21) is of diagnostic value in dealing with cases of unusual lymphoma. Furthermore, nonrandom chromosome breakage exhibited three distinct patterns that reflected three levels of etiologically relevant genetic change.

Familial predisposition to cancer and age at onset of disease in randomly selected cancer patients.

Incidence of malignancy among close relatives was used to evaluate the relationship of early age at diagnosis and familial cancer predisposition in a general population of cancer patients. The occurrence of cancer and other conditions in families of more than 1,350 randomly selected patients with a wide variety of malignancies was ascertained. Each patient was assigned to one of four study groups based on comparison of his age at diagnosis with the distribution of ages at diagnosis for his cancer site compiled by the Third National Cancer Survey. These groups consisted of patients whose ages at diagnosis were in: (1) the lowest decile, (2) the median decile, (3) above the median decile, and (4) between the lowest and median deciles. Person-years and calendar time at risk were calculated for first-degree relatives in each group. The numbers of cancers expected among these relatives were calculated using age- and time-specific incidence rates of a standard population. Statistical analysis of (1) the numbers of reported vs. expected cancers in relatives and (2) the numbers of families reporting cancer in parents or siblings of patients showed that a familial tendency to develop cancer exists in this randomly selected population of cancer patients, regardless of age at onset of malignancy in the proband. Conversely, early age at diagnosis of cancer may indicate genetic predisposition to malignancy only in exceptional cases.