RESUMO
Functional starter cultures demonstrating superior technological and food safety properties are advantageous to the food fermentation industry. We evaluated the efficacies of single- and double-bacteriocin-producing starters of Lactococcus lactis capable of producing the class I bacteriocins nisin A and/or lacticin 3147 in terms of starter performance. Single producers were generated by mobilizing the conjugative bacteriophage resistance plasmid pMRC01, carrying lacticin genetic determinants, or the conjugative transposon Tn5276, carrying nisin genetic determinants, to the commercial starter L. lactis CSK2775. The effect of bacteriocin coproduction was examined by superimposing pMRC01 into the newly constructed nisin transconjugant. Transconjugants were improved with regard to antimicrobial activity and bacteriophage insensitivity compared to the recipient strain, and the double producer was immune to both bacteriocins. Bacteriocin production in the starter was stable, although the recipient strain proved to be a more efficient acidifier than transconjugant derivatives. Overall, combinations of class I bacteriocins (the double producer or a combination of single producers) proved to be as effective as individual bacteriocins for controlling Listeria innocua growth in laboratory-scale cheeses. However, using the double producer in combination with the class II bacteriocin producer Lactobacillus plantarum or using the lacticin producer with the class II producer proved to be most effective for reducing bacterial load. As emergence of bacteriocin tolerance was reduced 10-fold in the presence of nisin and lacticin, we suggest that the double producer in conjunction with the class II producer could serve as a protective culture providing a food-grade, multihurdle approach to control pathogenic growth in a variety of industrial applications.IMPORTANCE We generated a suite of single- and double-bacteriocin-producing starter cultures capable of generating the class I bacteriocin lacticin 3147 or nisin or both bacteriocins simultaneously via conjugation. The transconjugants exhibited improved bacteriophage resistance and antimicrobial activity. The single producers proved to be as effective as the double-bacteriocin producer at reducing Listeria numbers in laboratory-scale cheese. However, combining the double producer or the lacticin-producing starter with a class II bacteriocin producer, Lactobacillus plantarum LMG P-26358, proved to be most effective at reducing Listeria numbers and was significantly better than a combination of the three bacteriocin-producing strains, as the double producer is not inhibited by either of the class I bacteriocins. Since the simultaneous use of lacticin and nisin should reduce the emergence of bacteriocin-tolerant derivatives, this study suggests that a protective starter system produced by bacteriocin stacking is a worthwhile multihurdle approach for food safety applications.
Assuntos
Bacteriocinas/metabolismo , Queijo/microbiologia , Microbiologia de Alimentos/métodos , Lactobacillus plantarum/metabolismo , Lactococcus lactis/metabolismo , Nisina/metabolismo , Animais , Bacteriocinas/análise , Bovinos , Queijo/análise , Fermentação , Leite/microbiologia , Nisina/análiseRESUMO
In 1962, Joseph Altman described that the brain generates neurons after the postnatal period, and this continues throughout your life (Altman, 1962). This was a breakthrough in the neuroscience field because before this the accepted paradigm was that the brain only generated neurons during the embryonal development. This discovery has been controversial ever since, especially since one of the areas of the brain with neurogenic properties is the hippocampus, which is the area involved in memory storage and neurodegenerative processes. The adult hippocampal neurogenesis modulates in response to different environmental factors. In this article, we review how exercise and cognitive and sexual activity can regulate the generation of new neurons in the hippocampal in an adult brain and the impact of these new neurons in the brain circuitry.
Assuntos
Cognição/fisiologia , Exercício Físico/fisiologia , Hipocampo/fisiologia , Neurogênese/fisiologia , Comportamento Sexual/fisiologia , Envelhecimento , Animais , HumanosRESUMO
PIP: A rare case of cervical pregnancy in the presence of an IUD is described. A 25-year-old woman with 2 children was treated with injectable hormones for intermittent vaginal bleeding after insertion of an IUD. She was later seen in a health center where removal of the IUD was recommended because of a suspected strangulating endocervical polyp. Uncontrollable hemorrhage during the removal resulted in emergency admittance to the General Hospital of Acapulco and a total hysterectomy and bilateral salpingo-oophorectomy. The postoperative course was uneventful. The case met some of Rubin's criteria for a true cervical pregnancy established in 1911: the uterine cavity was empty, and the site of implantation of the blastocyst was below the internal orifice of the cervix and 1 cm above the external cervical opening. Schneider applied the term cervical pregnancy to all cases in which the pregnancy is "obviously and predominantly" situated in the cervix, whether the placenta extended to the isthmus or the endometrium. No pregnancy of greater than 12 weeks is available for histologic proof because of the growth of the placenta in areas contiguous to the cervix and the effacing effect of the growing ovisac. Numerous etiologic factors for cervical pregnancy have been proposed, of which the 3 finding greatest acceptance have been lack of an adequate endometrium for nidation of the trophoblast, a rapid passage of the egg through the uterine cavity, and a premature closing of the internal opening of the cervix. The frequency of cervical pregnancy has been estimated at 1 in 1000 to 1 in 16,000 pregnancies, but its true frequency is unknown. The case described is of great interest because it occurred with an IUD in place.^ieng
Assuntos
Dispositivos Intrauterinos de Cobre/efeitos adversos , Gravidez Ectópica/etiologia , Adulto , Colo do Útero , Feminino , Humanos , Gravidez , Gravidez Ectópica/complicações , Hemorragia Uterina/etiologiaAssuntos
Células Apresentadoras de Antígenos/citologia , Antígenos CD19/imunologia , Imunoterapia Adotiva/métodos , Leucemia de Células B/terapia , Linfócitos T Citotóxicos/citologia , Células Apresentadoras de Antígenos/imunologia , Divisão Celular/imunologia , Humanos , Linfoma de Células B/terapia , Linfócitos T Citotóxicos/imunologiaRESUMO
BACKGROUND: The production of therapeutic T-cell populations for adoptive immunotherapy of cancer requires extensive ex vivo cell processing, including the isolation or creation of Ag-specific T cells and their subsequent propagation to clinically relevant numbers. These procedures must be performed according to the principles of current good manufacturing practices (cGMP) for phase I clinical trials to ensure the identity, purity potency and safety of the cellular product. In this report we describe our approach to manufacturing and characterizing bulk populations of gene-modified autologous T cells for use in treating follicular lymphoma. METHODS: PBMC from healthy donors, obtained after informed consent, were stimulated in vitro with Ab to CD3epsilon (OKT3) and recombinant human IL-2 and then electroporated with plasmid DNA containing a human CD19-specific chimeric Ag receptor (CAR) gene and HSV-1 thymidine kinase (TK) gene. Stably transfected cells were selected in cytocidal concentrations of hygromycin B over multiple 14-day stimulation culture cycles and then cryopreserved. Vials of cryopreserved/selected T cells were used to initiate T-cell expansion cultures to produce cell products for clinical infusion. These cultures were characterized for phenotype, function and suitability for use in adoptive immunotherapy studies. RESULTS: Our results demonstrate that bulk populations of gene-modified T cells derived from peripheral blood of healthy donors express CD19+ chimeric Ag receptor at low levels and can specifically lyse CD19+ target cells in vitro. These cells display a differentiated T-effector phenotype, are sensitive to ganciclovir-mediated killing and display a non-transformed phenotype. TCR Vbeta usage indicated that all populations tested were polyclonal. Ex vivo cell expansion from cryopreserved cell banks is sufficient to produce doses of between 5 x 10(9) and 1 x 10(10) cells/run. One of three transductions resulted in a population of cells that was not suitable for infusion but was identified during release testing. No populations displayed any evidence of bacterial, fungal or mycoplasma contamination. DISCUSSION: We have established a manufacturing strategy that is being used to produce T cells for a phase I clinical trial for follicular lymphoma. Genetically modified T cells have been characterized by cell-surface marker phenotype, functional activity against CD19+ targets and requisite safety testing. These pre-clinical data confirm the feasibility of this approach to manufacturing T-cell products.