Tandem haematopoietic stem cell transplantation versus single cell transplant and BV maintenance in relapsed/refractory Hodgkin lymphoma: A matched cohort analysis from the LYSA

Autologous hematopoietic stem cell transplant (ASCT) is the standard curative treatment for patients with high-risk relapsed/refractory Hodgkin lymphoma (R/R HL). The AETHERA study showed survival gain with Brentuximab Vedotin (BV) maintenance after ASCT in BV-naive patients, which was recently confirmed in the retrospective AMAHRELIS cohort, including a majority of BV-exposed patients. However, this approach has not been compared to intensive tandem auto/auto or auto/allo transplant strategies, which were used before BV approval. Here, we matched BV maintenance (AMAHRELIS) and tandem SCT (HR2009) cohorts, and observed that BV maintenance was associated with better survival outcome in patients with HR R/R HL.

Early melanoma invasivity correlates with gut fungal and bacterial profiles

BACKGROUND

The microbiome is emerging as a crucial player of the immune checkpoint in cancer. Melanoma is a highly immunogenic tumour, and the gut microbiome composition has been correlated to prognosis and evolution of advanced melanoma and proposed as biomarker for immune checkpoint therapy.

OBJECTIVES

We investigated the gut fungal and bacterial composition in early-stage melanoma and correlated microbial profiles with histopathological features.

METHODS

Bacterial 16S rRNA and fungal ITS region sequencing was performed from faecal samples of patients affected by stage I and II melanoma, and healthy controls. A meta-analysis with gut microbiota data from metastatic melanoma patients was also carried out.

RESULTS

We found a combination of gut fungal and bacterial profiles significantly discriminating M patients from controls. In melanoma patients, we observed an abundance of Prevotella copri and yeasts belonging to the Saccharomycetales order. We found bacterial and fungal community correlated to melanoma invasiveness, whereas specific fungal profile correlated to melanoma regression. Bacteroides was identified as general marker of immunogenicity, being shared by regressive and invasive melanoma. In addition, the bacterial community from stage I and II patients were different in structure and richer than those from metastatic melanoma patients.

CONCLUSIONS

Gut microbiota composition in early-stage melanoma changes along the gradient from in situ to invasive (and metastatic) melanoma. Changes in the microbiota and mycobiota are correlated to the histological features of early-stage melanoma, and to the clinical course and response to immune therapies of advanced stage melanoma, through a direct or indirect immunomodulation.

Nod2 Deficiency in mice is Associated with Microbiota Variation Favouring the Expansion of mucosal CD4+ LAP+ Regulatory Cells

Nucleotide-binding Oligomerization Domain-2 (NOD2) mutations are associated with an increased risk to develop Crohn's Disease. In previous studies, we have shown that Nod2-/- mice manifest increased proportion of Lamina Propria (LP) CD4+ LAP+ Foxp3- regulatory cells, when compared with Nod2+/+ mice, while CD4+ Foxp3 + regulatory cells were not affected. Here, we investigated the Nod2 gut microbiota, by 16S rRNA pyrosequencing, at steady state and after TNBS-colitis induction in mice reared separately or in cohousing, correlating the microbial profiles with LP regulatory T cells proportion and tissue cytokines content. We found that enrichment of Rikenella and Alistipes (Rikenellaceae) in Nod2-/- mice at 8 weeks of age reared separately was associated with increased proportion of CD4+ LAP+ Foxp3- cells and less severe TNBS-colitis. In co-housed mice the acquisition of Rickenellaceae by Nod2+/+ mice was associated with increased CD4+ LAP+ Foxp3- proportion and less severe colitis. Severe colitis was associated with enrichment of gram-negative pathobionts (Escherichia and Enterococcus), while less severe colitis with protective bacteria (Barnesiella, Odoribacter and Clostridium IV). Environmental factors acting on genetic background with different outcomes according to their impact on microbiota, predispose in different ways to inflammation. These results open a new scenario for therapeutic attempt to re-establish eubiosis in Inflammatory Bowel Disease patients with NOD2 polymorphisms.

Microbiota and environmental stress: how pollution affects microbial communities in Manila clams

Given the crucial role of microbiota in host development, health, and environmental interactions, genomic analyses focusing on host-microbiota interactions should certainly be considered in the investigation of the adaptive mechanisms to environmental stress. Recently, several studies suggested that microbiota associated to digestive tract is a key, although still not fully understood, player that must be considered to assess the toxicity of environmental contaminants. Bacteria-dependent metabolism of xenobiotics may indeed modulate the host toxicity. Conversely, environmental variables (including pollution) may alter the microbial community and/or its metabolic activity leading to host physiological alterations that may contribute to their toxicity. Here, 16s rRNA gene amplicon sequencing has been applied to characterize the hepatopancreas microbiota composition of the Manila clam, Ruditapes philippinarum. The animals were collected in the Venice lagoon area, which is subject to different anthropogenic pressures, mainly represented by the industrial activities of Porto Marghera (PM). Seasonal and geographic differences in clam microbiotas were explored and linked to host response to chemical stress identified in a previous study at the transcriptome level, establishing potential interactions among hosts, microbes, and environmental parameters. The obtained results showed the recurrent presence of putatively detoxifying bacterial taxa in PM clams during winter and over-representation of several metabolic pathways involved in xenobiotic degradation, which suggested the potential for host-microbial synergistic detoxifying actions. Strong interaction between seasonal and chemically-induced responses was also observed, which partially obscured such potentially synergistic actions. Seasonal variables and exposure to toxicants were therefore shown to interact and substantially affect clam microbiota, which appeared to mirror host response to environmental variation. It is clear that understanding how animals respond to chemical stress cannot ignore a key component of such response, the microbiota.

Effects of near-infrared laser radiation on the survival and inflammatory potential of Candida spp. involved in the pathogenesis of chemotherapy-induced oral mucositis

Candida spp. usually colonize ulcerative lesions of atrophic mucosa in patients with chemotherapy-induced oral mucositis inducing severe inflammation. The spread of antifungal-resistant strains strongly encouraged the search of complementary or alternative therapeutic strategies to cure inflamed mucosa. In this paper, we studied the effects of a near-infrared (NIR) laser system with dual-wavelength emission (808 nm + 904 nm) on the survival and inflammatory potential of C. albicans, C. glabrata, and C. parapsilosis. Laser treatment was performed with a Multiwave Locked System laser. Survival and apoptosis of fungal strains were evaluated by colony-forming units (CFU) counting and annexin V staining. Cytokine production was evaluated by ImmunoPlex array. Laser treatment significantly affected the survival of Candida spp. by inducing apoptosis and induced a lower production of inflammatory cytokines by dendritic cells compared to untreated fungi. No differences in the survival and inflammatory potential were recorded in treated or untreated Saccharomyces cerevisiae cells, used as the control non-pathogenic microorganism. Laser treatment altered the survival and inflammatory potential of pathogenic Candida spp. These data provide experimental support to the use of NIR laser radiation as a co-adjuvant of antifungal therapy in patients with oral mucositis (OM) complicated by Candida infections.

Genomics approach to the analysis of bacterial communities dynamics in Hirschsprung's disease-associated enterocolitis: a pilot study

INTRODUCTION

The most invalidating and life-threatening complication in Hirschsprung's disease patients (HSCR) is Hirschsprung's disease-associated enterocolitis (HAEC). The mechanisms underlying enterocolitis have not been identified. The limited knowledge of the role of intestinal microflora is in part due to the complexity of the intestinal microbiome and to the limitation of cultivation-based technologies, given that less than 25% of the intestinal bacterial species can be cultured.

MATERIALS AND METHODS

We used amplified ribosomal DNA restriction analysis (ARDRA) with four different restriction enzymes to study variations of microflora composition of the stools of a selected HSCR patient in different clinical conditions (acute phase vs. remission).

RESULTS

We assessed a total of 15 stool specimens belonging to the same 3-year-old male patient suffering from HSCR, which were harvested during 4 HAEC episodes and remission phases. Restriction analysis showed that HAEC episodes seem to cluster together at ARDRA analysis, thus suggesting a sort of predisposing bacterial community for HAEC development and the need for a microflora equilibrium to maintain wellness.

CONCLUSIONS

This approach proved to be effective, useful and powerful in assessing microflora dynamics and indicated that the differences in microflora associated with acute HAEC or remission are likely to result from a combination of disease activity and different antibiotic therapies. ARDRA proved to be useful in discriminating disease versus remission. Our findings indicated that HAEC results from a change in the equilibrium between bacterial species or from altered discrimination of harmless from harmful microorganisms, challenging the definition of pathogenic and non-pathogenic species. Based on these results, we propose ARDRA as a rapid inexpensive tool to assess microflora dynamics during HAEC episodes.

Yeast as a model to investigate the mitochondrial role in adaptation to dietary fat and calorie surplus

Several research strategies are focused towards understanding the genetic basis and molecular mechanisms that regulate uptake, synthesis, deposition, and mobilization of lipids, in the context of energy homeostasis. Because of the complexity of the problem, major input comes from the use of model systems. The aim of this work was to test the feasibility of using yeast as a model organism for studies related to dietary challenges due to high fat diet and investigate the correlation between FA metabolism and oxidative metabolism. In particular, we ask to what extent the utilization of oleic acid is dependent on mitochondrial function. We studied growth on oleic acid as a sole carbon source, and oleate stress (growth in 2 and 5% oleate) in both laboratory (BY4741 wild-type and Δsco1, Δsco2, Δtgl3, Δtgl4 mutants) and natural strains, comparing the growth phenotypes with the respiratory behaviour for each strain. We confirmed that respiratory competence is fundamental for growth on oleic acid, since the respiratory deficient mutant Δsco1 was unable to grow on oleic acid. In order to understand if the ability to use oleate as carbon source and adapt to high oleate concentrations is a general trait for the Saccharomyces cerevisiae genus, we also studied some natural strains, both diploid and haploid, identifying two meiotic derivatives of SGU90 as unable to grow in oleic acid as a sole carbon source. We investigate some aspects of mitochondrial metabolism in order to gain insights on this new finding.

Gene transcription analysis of Saccharomyces cerevisiae exposed to neocarzinostatin protein-chromophore complex reveals evidence of DNA damage, a potential mechanism of resistance, and consequences of prolonged exposure

The natural product neocarzinostatin (NCS), a protein-small molecule complex, exhibits potent antiproliferative activity in mammalian cells but has little apparent effect on the growth of the unicellular eukaryotic organism, Saccharomyces cerevisiae. Here, we show by whole-genome transcription profiling experiments that incubation of S. cerevisiae with NCS leads to dramatic and wide-ranging modifications in the expression profile of yeast genes. Approximately 18% of yeast transcripts are altered by 2-fold or more within 4 h of treatment with NCS. Analysis of the observed transcription profile provides evidence that yeast rapidly and continuously overexpress multiple DNA-damage repair genes during NCS exposure. Perhaps to meet the energetic requirements of continuous DNA-damage repair, yeast cells enter respiration upon prolonged exposure to NCS, although grown in nutrient-rich medium. The NCS protein component is readily transported into S. cerevisiae, as demonstrated by fluorescence microscopy of yeast treated with fluorescently labeled NCS. Transcription profiling experiments with neocarzinostatin protein alone implicate a specific resistance mechanism in yeast that targets the NCS protein component, one involving the nonclassical export pathway. These experiments provide a detailed picture of the effects of exposure to NCS upon yeast and the mechanisms they engage as a response to this protein-small molecule DNA-damaging agent.

Biodiversity and horizontal gene transfer in culturable bacteria isolated from activated sludge enriched in nonylphenol ethoxylates

One hundred and twenty bacterial isolates, from activated sludge of a treatment plant collecting wastes enriched in ethoxylated nonylphenols, were studied. Sixty isolates were selected on rich medium and 60 on mineral medium containing two nonylphenol ethoxylates as the sole carbon source. Analysis of biodiversity at the species level was performed by comparing the AluI restriction patterns of the 16S ribosomal DNA amplified by PCR from 120 isolates. The rDNA restriction analysis enabled us to cluster the isolates into 15 groups, five of which represented nearly 77% of the community. Phylogenetic analysis of five strains belonging to these main groups made it possible to assign four of them to the genera Acinetobacter, Aeromonas and Shewanella and one to the Proteus group. The analysis of plasmid content showed a high variability and suggested that horizontal gene transfer had taken place at the intraspecific, interspecific and intergeneric levels.

Manifold anomalies in gene expression in a vineyard isolate of Saccharomyces cerevisiae revealed by DNA microarray analysis

Genome-wide transcriptional profiling has important applications in evolutionary biology for assaying the extent of heterozygosity for alleles showing quantitative variation in gene expression in natural populations. We have used DNA microarray analysis to study the global pattern of transcription in a homothallic strain of Saccharomyces cerevisiae isolated from wine grapes in a Tuscan vineyard, along with the diploid progeny obtained after sporulation. The parental strain shows 2:2 segregation (heterozygosity) for three unlinked loci. One determines resistance to trifluoroleucine; another, resistance to copper sulfate; and the third is associated with a morphological phenotype observed as colonies with a ridged surface resembling a filigree. Global expression analysis of the progeny with the filigreed and smooth colony phenotypes revealed a greater than 2-fold difference in transcription for 378 genes (6% of the genome). A large number of the overexpressed genes function in pathways of amino acid biosynthesis (particularly methionine) and sulfur or nitrogen assimilation, whereas many of the underexpressed genes are amino acid permeases. These wholesale changes in amino acid metabolism segregate as a suite of traits resulting from a single gene or a small number of genes. We conclude that natural vineyard populations of S. cerevisiae can harbor alleles that cause massive alterations in the global patterns of gene expression. Hence, studies of expression variation in natural populations, without accompanying segregation analysis, may give a false picture of the number of segregating genes underlying the variation.

Identification by functional analysis of the gene encoding alpha-isopropylmalate synthase II (LEU9) in Saccharomyces cerevisiae

The function of the open reading frame (ORF) YOR108w of Saccharomyces cerevisiae has been analysed. The deletion of this ORF from chromosome XV did not give an identifiable phenotype. A mutant in which both ORF YOR108w and LEU4 gene have been deleted proved to be leucine auxotrophic and alpha-isopropylmalate synthase (alpha-IPMS)-negative. This mutant recovered alpha-IPMS activity and a Leu(+) phenotype when transformed with a plasmid copy of YOR108w. These data and the sequence homology indicated that YOR108w is the structural gene for alpha-IPMS II, responsible for the residual alpha-IPMS activity found in a leu4Delta strain. The leu4Delta strain appeared to be very sensitive to the leucine analogue trifluoroleucine. In the absence of leucine, its growth was not much impaired in glucose but more on non-fermentable carbon sources.

Trifluoroleucine resistance as a dominant molecular marker in transformation of strains of Saccharomyces cerevisiae isolated from wine

The resistance to 5,5,5-trifluoro-DL-leucine, encoded by the dominant allele LEU4-1, was used as a selectable marker to transform laboratory and natural Saccharomyces cerevisiae strains by the lithium acetate procedure. Results of transformation of S. cerevisiae laboratory and wine natural strains showed that trifluoroleucine resistance is a very effective selection marker and can be widely used to transform prototrophic S. cerevisiae strains. The LEU4-1 gene could also be exploited to improve wine flavour, as indicated by the higher isoamyl alcohol content of the transformants compared to the parental strains.

Disruption and phenotypic analysis of six novel genes from chromosome IV of Saccharomyces cerevisiae reveal YDL060w as an essential gene for vegetative growth

The disruption of six novel genes (YDL059c, YDL060w, YDL063c, YDL065c, YDL070w and YDL110c), localized on the left arm of chromosome IV in Saccharomyces cerevisiae, is reported. A PCR-based strategy was used to construct disruption cassettes in which the kanMX4 dominant marker was introduced between two long flanking homology regions, homologous to the promoter and terminator sequences of the target gene (Wach et al., 1994). The disruption cassettes were used to generate homologous recombinants in two diploid strains with different genetic backgrounds (FY1679 and CEN. PK2), selecting for geneticin (G418) resistance conferred by the presence of the dominant marker kanMX4. The correctness of the cassette integration was tested by PCR. After sporulation and tetrad analysis of the heterozygous deletant diploids, geneticin-resistant haploids carrying the disrupted allele were isolated. YDL060w was shown to be an essential gene for vegetative growth. A more detailed phenotypic analysis of the non-lethal haploid deletant strains was performed, looking at cell and colony morphology, growth capability on different media at different temperatures, and ability to conjugate. Homozygous deletant diploids were also constructed and tested for sporulation. Only minor differences between parental and mutant strains were found for some deletant haploids.

Trifluoroleucine resistance and regulation of alpha-isopropyl malate synthase in Saccharomyces cerevisiae

Seven spontaneous Saccharomyces cerevisiae mutants that express dominant resistance to 5,5,5-trifluoro-DL-leucine have been characterised at the molecular level. The gene responsible for the resistance was cloned from one of the mutants (FSC2.4). Determination of its nucleotide sequence showed that it was an allele of LEU4 (LEU4-1), the gene that encodes alpha-isopropyl malate synthase I (alpha-IPM synthase I), and that the mutation involved a codon deletion localised close to the 3' end of the LEU4 ORF. Six different point mutations--four transitions and two transversions--were found in the remaining mutants. Alpha-IPM synthase activity was found to be insensitive to feedback inhibition by leucine in five of the strains. In the other two the enzyme was resistant to Zn2+-mediated inactivation by Coenzyme A, a previously postulated control mechanism in energy metabolism; as far as we know, this represents the first direct in vivo evidence for this mechanism. The seven mutations define a region, the R-region, involved in both leucine feedback inhibition and in Zn2+-mediated inactivation by CoA. Deletion experiments involving the R-region showed that it is also necessary for enzyme activity.

Paralogous histidine biosynthetic genes: evolutionary analysis of the Saccharomyces cerevisiae HIS6 and HIS7 genes

The HIS6 gene from Saccharomyces cerevisiae strain YNN282 is able to complement both the S. cerevisiae his6 and the Escherichia coli hisA mutations. The cloning and the nucleotide sequence indicated that this gene encodes a putative phosphoribosyl-5-amino-1-phosphoribosyl-4-imidazolecarboxiamide isomerase (5' Pro-FAR isomerase, EC 5.3.1.16) of 261 amino acids, with a molecular weight of 29,554. The HIS6 gene product shares a significant degree of sequence similarity with the prokaryotic HisA proteins and HisF proteins, and with the C-terminal domain of the S. cerevisiae HIS7 protein (homologous to HisF), indicating that the yeast HIS6 and HIS7 genes are paralogous. Moreover, the HIS6 gene is organized into two homologous modules half the size of the entire gene, typical of all the known prokaryotic hisA and hisF genes. The structure of the yeast HIS6 gene supports the two-step evolutionary model suggested by Fani et al. (J. Mol. Evol. 1994; 38: 489-495) to explain the present-day hisA and hisF genes. According to this idea, the hisF gene originated from the duplication of an ancestral hisA gene which, in turn, was the result of an earlier gene elongation event involving an ancestral module half the size of the extant gene. Results reported in this paper also suggest that these two successive paralogous gene duplications took probably place in the early steps of molecular evolution of the histidine pathway, well before the diversification of the three domains, and that this pathway was one of the metabolic activities of the last common ancestor. The molecular evolution of the yeast HIS6 and HIS7 genes is also discussed.

Genetic and biochemical characterization of Saccharomyces cerevisiae mutants resistant to trifluoroleucine

Eighteen mutants resistant to 5',5',5'-trifluoroleucine (TFL), a leucine analog, were isolated in Saccharomyces cerevisiae strains YNN281 and YNN282. The mutants were characterized genetically and clustered in two groups, one comprising all the dominant (TFL1) and the other one all the recessive (tfl2) mutations. Genetic and biochemical data suggested that the dominant mutations are located on the LEU4 gene, coding for alpha-isopropylmalate synthase I. These mutations resulted in accumulation of leucine as a consequence of the synthesis of an enzyme insensitive to the feedback inhibition by leucine. Leucine excretion in the TFL1 mutants appeared to be affected by the genetic background of the strain and was greatly influenced by lysine metabolism. The measurement of intra- and extracellular amino acid concentrations in prototrophic strains carrying TFL1 or tfl2 genes showed that both were leucine overproducers. Some of the TFL-resistant mutants were tested in alcoholic fermentation of grape must: analysis of the fermentation secondary metabolites showed that the major effect of the TFL-resistant strains was an increased production of isoamyl alcohol compared to that of the parental strain.

DNA fingerprinting by random amplified polymorphic DNA and restriction fragment length polymorphism is useful for yeast typing

Random amplified polymorphic DNA (RAPD) analysis was applied to genomic DNA from nineteen yeast strains belonging to the genera Saccharomyces and Zygosaccharomyces. Results obtained with five primers indicated that this technique is a powerful tool for yeast differentiation and identification. The data were consistent with those derived from restriction fragment length polymorphism (RFLP) using two S. cerevisiae DNA probes. We conclude that RAPD fingerprinting, combined with the analysis of RFLP, can provide unambiguous type assignment in yeasts.