Purification and genetic characterization of gassericin E, a novel co-culture inducible bacteriocin from Lactobacillus gasseri EV1461 isolated from the vagina of a healthy woman

This work was supported by the Spanish Ministry of Economy and Competitiveness (MINECO) through the Project AGL2012-33400 and AGL2013-41980-P, and by the Junta de Andalucía Excellence Project AGR-07345. These projects included FEDER funds. AMB was the recipient of a post-doctoral grant awarded by the Junta de Andalucía as part of the Project AGR-07345.Background: Lactobacillus gasseri is one of the dominant Lactobacillus species in the vaginal ecosystem. Some strains of this species have a high potential for being used as probiotics in order to maintain vaginal homeostasis, since they may confer colonization resistance against pathogens in the vagina by direct inhibition through production of antimicrobial compounds, as bacteriocins. In this work we have studied bacteriocin production of gassericin E (GasE), a novel bacteriocin produced by L. gasseri EV1461, a strain isolated from the vagina of a healthy woman, and whose production was shown to be promoted by the presence of certain specific bacteria in co-culture. Biochemical and genetic characterization of this novel bacteriocin are addressed. Results: We found that the inhibitory spectrum of L. gasseri EV1461 was broad, being directed to species both related and non-related to the producing strain. Interestingly, L. gasseri EV1461 inhibited the grown of pathogens usually associated with bacterial vaginosis (BV). The antimicrobial activity was due to the production of a novel bacteriocin, gassericin E (GasE). Production of this bacteriocin in broth medium only was achieved at high cell densities. At low cell densities, bacteriocin production ceased and only was restored after the addition of a supernatant from a previous bacteriocin-producing EV1461 culture (autoinduction), or through co-cultivation with several other Gram-positive strains (inducing bacteria). DNA sequence of the GasE locus revealed the presence of two putative operons which could be involved in biosynthesis and immunity of this bacteriocin (gaeAXI), and in regulation, transport and processing (gaePKRTC). The gaePKR encodes a putative three-component regulatory system, involving an autoinducer peptide (GaeP), a histidine protein kinase (GaeK) and a response regulator (GaeR), while the gaeTC encodes for an ABC transporter (GaeT) and their accessory protein (GaeC), involved in transport and processing of the bacteriocin. The gaeAXI, encodes for the bacteriocin gassericin E (GasE), a putative peptide bacteriocin (GaeX), and their immunity protein (GaeI). Conclusions: The origin of the strain (vagina of healthy woman) and its ability to produce bacteriocins with inhibitory activity against vaginal pathogens may be an advantage for using L. gasseri EV1461 as a probiotic strain to fight and/or prevent bacterial infections as bacterial vaginosis (BV), since it could be better adapted to live and compete into the vaginal environment.Publisher PDFPeer reviewe

Nueva estrategia didáctica para fomentar la participación del alumnado en el proceso de aprendizaje en el ámbito de la tecnología farmacéutica (continuación)

Depto. de Farmacia Galénica y Tecnología AlimentariaFac. de FarmaciaFALSEsubmitte

Rewriting and narrowing for constructor systems with call-time choice semantics

Non-confluent and non-terminating constructor-based term rewrite systems are useful for the purpose of specification and programming. In particular, existing functional logic languages use such kind of rewrite systems to define possibly non-strict non-deterministic functions. The semantics adopted for non-determinism is call-time choice, whose combination with non-strictness is a non trivial issue, addressed years ago from a semantic point of view with the Constructor-based Rewriting Logic (CRWL), a well-known semantic framework commonly accepted as suitable semantic basis of modern functional logic languages. A drawback of CRWL is that it does not come with a proper notion of one-step reduction, which would be very useful to understand and reason about how computations proceed. In this paper we develop thoroughly the theory for the first order version of letrewriting, a simple reduction notion close to that of classical term rewriting, but extended with a let-binding construction to adequately express the combination of call-time choice with non-strict semantics. Let-rewriting can be seen as a particular textual presentation of term graph rewriting. We investigate the properties of let-rewriting, most remarkably their equivalence with respect to a conservative extension of the CRWL-semantics coping with let-bindings, and we show by some case studies that having two interchangeable formal views (reduction/semantics) of the same language is a powerful reasoning tool. After that, we provide a notion of let-narrowing which is adequate for call-time choice as proved by soundness and completeness results of let-narrowing with respect to letre writing. Moreover, we relate those let-rewriting and let-narrowing relations (and hence CRWL) with ordinary term rewriting and narrowing, providing in particular soundness and completeness of let-rewriting with respect to term rewriting for a class of programs which are deterministic in a semantic sense

Detection and outcome of occult leptomeningeal disease in diffuse large B-cell lymphoma and Burkitt lymphoma

The benefit of intrathecal therapy and systemic rituximab on the outcome of diffuse large B-cell lymphoma at risk of central nervous system disease is controversial. Furthermore, the effect of intrathecal treatment and rituximab in diffuse large B-cell and Burkitt lymphoma with occult leptomeningeal disease detected by flow cytometry at diagnosis is unknown. Untreated diffuse large B-cell (n=246) and Burkitt (n=80) lymphoma at clinical risk of central nervous system disease and having had pre-treatment cerebrospinal fluid were analyzed by flow cytometry and cytology. Spinal fluid involvement was detected by flow cytometry alone (occult) in 33 (13%) diffuse large B-cell and 9 (11%) Burkitt lymphoma patients, and detected by cytology in 11 (4.5%) and 5 (6%) patients, respectively. Diffuse large B-cell lymphoma with occult spinal fluid involvement had poorer survival (P=0.0001) and freedom from central nervous system relapse (P<0.0001) compared to negative cases. Burkitt lymphoma with occult spinal fluid involvement had an inferior freedom from central nervous system relapse (P=0.026) but not survival. The amount of intrathecal chemotherapy was quantitatively associated with survival in diffuse large B-cell lymphoma with (P=0.02) and without (P=0.001) occult spinal fluid involvement. However, progression of systemic disease and not control of central nervous system disease was the principal cause of treatment failure. In diffuse large B-cell lymphoma, systemic rituximab was associated with improved freedom from central nervous system relapse (P=0.003) but not with survival. Our results suggest that patients at risk of central nervous system disease should be evaluated by flow cytometry and that intrathecal prophylaxis/therapy is beneficial

Response to Novel Drugs before and after Allogeneic Stem Cell Transplantation in Patients with Relapsed Multiple Myeloma

Multiple myeloma (MM) remains as an incurable disease and, although allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a potentially curative approach, most patients ultimately relapse, and their treatment remains challenging. Because allo-HSCT can modify not only the biology of the disease, but also the immune system and the microenvironment, it can potentially enhance the response to rescue therapies. Information on the efficacy and safety of novel drugs in patients relapsing after allo-HSCT is lacking, however. The objectives of this study were to evaluate the efficacy and toxicity of rescue therapies in patients with MM who relapsed after allo-HSCT, as well as to compare their efficacy before and after allo-HSCT. This retrospective multicenter study included 126 consecutive patients with MM who underwent allo-HSCT between 2000 and 2013 at 8 Spanish centers. All patients engrafted. The incidence of grade II-IV acute graft-versus-host disease (GVHD) was 47%, and nonrelapse mortality within the first 100 days post-transplantation was 13%. After a median follow-up of 92 months, overall survival (OS) was 51% at 2 years and 43% at 5 years. The median progression-free survival after allo-HSCT was 7 months, whereas the median OS after relapse was 33 months. Patients relapsing in the first 6 months after transplantation had a dismal prognosis compared with those who relapsed later (median OS, 11 months versus 120 months; P <.001). The absence of chronic GVHD was associated with reduced OS after relapse (hazard ratio, 3.44; P <.001). Most patients responded to rescue therapies, including proteasome inhibitors (PIs; 62%) and immunomodulatory drugs (IMiDs; 77%), with a good toxicity profile. An in-depth evaluation, including the type and intensity of PI- and IMiD-based combinations used before and after allo-HSCT, showed that the overall response rate and duration of response after allo-HSCT were similar to those seen in the pretransplantation period. Patients with MM who relapse after allo-HSCT should be considered candidates for therapy with new drugs, which can achieve similar response rates with similar durability as seen in the pretransplantation period. This pattern does not follow the usual course of the disease outside the transplantation setting, where response rates and time to progression decreases with each consecutive line of treatment

Axicabtagene ciloleucel compared to tisagenlecleucel for the treatment of aggressive B-cell lymphoma

Axicabtagene ciloleucel (axi-cel) and tisagenlecleucel (tisa-cel) are CD19-targeted chimeric antigen receptor (CAR) T cells approved for relapsed/refractory (R/R) large B-cell lymphoma (LBCL). We performed a retrospective study to evaluate safety and efficacy of axi-cel and tisa-cel outside the setting of a clinical trial. Data from consecutive patients with R/R LBCL who underwent apheresis for axi-cel or tisa-cel were retrospectively collected from 12 Spanish centers. A total of 307 patients underwent apheresis for axi-cel (n=152) and tisa-cel (n=155) from November 2018 to August 2021, of which 261 (85%) received a CAR T infusion (88% and 82%, respectively). Median time from apheresis to infusion was 41 days for axi-cel and 52 days for tisa-cel (P =0.006). None of the baseline characteristics were significantly different between both cohorts. Both cytokine release syndrome and neurologic events (NE) were more frequent in the axi-cel group (88% vs. 73%, P =0.003, and 42% vs. 16%, P <0.001, respectively). Infections in the first 6 months post-infusion were also more common in patients treated with axi-cel (38% vs. 25%, P =0.033). Non-relapse mortality was not significantly different between the axi-cel and tisa-cel groups (7% and 4%, respectively, P =0.298). With a median follow-up of 9.2 months, median PFS and OS were 5.9 and 3 months, and 13.9 and 11.2 months for axi-cel and tisa-cel, respectively. The 12-month PFS and OS for axi-cel and tisa-cel were 41% and 33% (P =0.195), 51% and 47% (P =0.191), respectively. Factors associated with lower OS in the multivariate analysis were increased lactate dehydrogenase, ECOG ≥2 and progressive disease before lympho-depletion. Safety and efficacy results in our real-world experience were comparable with those reported in the pivotal trials. Patients treated with axi-cel experienced more toxicity but similar non-relapse mortality compared with those receiving tisa-cel. Efficacy was not significantly different between both products

Silver clusters of five atoms as highly selective antitumoral agents through irreversible oxidation of thiols

Low atomicity clusters present properties dependent on the size, due to the quantum confinement, with well-defined electronic structures and high stability. Here it is shown that Ag5 clusters catalyze the complete oxidation of sulfur to S+6. Ag5 catalytic activity increases with different oxidant species in the order O2 ≪ H2O2 < OH•. Selective oxidation of thiols on the cysteine residues of glutathione and thioredoxin is the primary mechanism human cells have to maintain redox homeostasis. Contingent upon oxidant concentration, Ag5 catalyzes the irreversible oxidation of glutathione and thioredoxin, triggering apoptosis. Modification of the intracellular environment to a more oxidized state to mimic conditions within cancer cells through the expression of an activated oncogene (HRASG12V) or through ARID1A mutation, sensitizes cells to Ag5 mediated apoptosis. While cancers evolve to evade treatments designed to target pathways or genetic mutations that drive them, they cannot evade a treatment that takes advantage of aberrant redox homeostasis, which is essential for tumor progression and metastasis. Ag5 has antitumor activity in mice with orthotopic lung tumors reducing primary tumor size, and the burden of affected lymphatic nodes. The findings suggest the unique intracellular redox chemistry of Ag5 may lead to new redox-based approaches to cancer therapyThis research was partially supported by 1) “la Caixa” Foundation, Ref. LCF/PR/PR12/11070003 to F.D. and M.A.L.Q.; 2) Ministerio de Ciencia, Innovación y Universidades (MAT2017-89678-R, AEI/FEDER, UE) to F.D. and A.V.; 3) the Consellería de Educación (Xunta de Galicia), Grants No. Grupos Ref. Comp. ED431C 2017/22, ED431C 2019/13 and AEMAT-ED431E2018/08 to M.A.L.Q.; and ED431C 2019/13 to A.V. This project has received funding from the European Union's Horizon 2020 Research and Innovation Programme (Bac-To-Fuel) under Grant Agreement No. 825999 (M.A.L.Q.). J.C.H. acknowledge financial support from European Union's Horizon 2020 research and innovation programme under grant agreement no. 823717-ESTEEM3, and the MICIIN (projects PID2019-107578GA-100 and PID-110018GA-100). J.M.D, L.J.G., and F.G.R. thank to the ANPCyT (PICT 2015-2285 and 2017-3944), UNLP (Project 11/X790) and the partial support by the Laboratório Nacional de Luz Síncrotron (LNLS, Brazil) under proposal SXS-20180280. G.B. acknowledges the CINECA Award N. IsC51, year 2017, under the ISCRA initiative, for the availability of high-performance computing resources and support. D.B. expresses gratitude for a postdoctoral grant from Xunta de Galicia, Spain (POS-A/2013/018). B.D. expresses gratitude for a predoctoral grant from MICINN, Spain (BES-2016-076765). F.D. and A.V. also acknowledged Xunta de Galicia (Centro singular de investigación de Galicia accreditation 2019-2022 ref ED431G 2019/02) and the European Union (European Regional Development Fund – ERDF). Work in M.P.M.'s lab was supported by the Medical Research Council UK (MC_U105663142). T.G.C. gratefully acknowledges the technical assistance of María José Otero-Fraga (FIDIS)S