Artículos de revistas: "Delayed strain"

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Wang, Shifeng, Yuhua Li, Giorgio Scarpellini, Wei Kong, HuoYing Shi, Chang-Ho Baek, Bronwyn Gunn et al. "Salmonella Vaccine Vectors Displaying Delayed Antigen Synthesis InVivo To Enhance Immunogenicity". Infection and Immunity 78, n.º 9 (6 de julio de 2010): 3969–80. http://dx.doi.org/10.1128/iai.00444-10.

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ABSTRACTWe have developed a regulated delayed antigen synthesis (RDAS) system for use in recombinant attenuatedSalmonellavaccine (RASV) strains to enhance immune responses by reducing the adverse effects of high-level antigen synthesis. This system includes a chromosomal repressor gene,lacI, expressed from the arabinose-regulatedaraCPBADpromoter. LacI serves to regulate expression from a plasmid promoter, Ptrc, that directs antigen synthesis. In the presence of arabinose LacI is produced, which binds to Ptrc, blocking antigen synthesis.In vivo, an arabinose-poor environment, the concentration of LacI decreases with each cell division, allowing increased antigen synthesis. To optimize the system and for comparison, we altered thelacIribosome-binding site, start codon, and/or codon content to construct RDAS strains χ9095, χ9959, and χ9241, synthesizing from low to high levels of LacI, respectively, and non-RDAS strain χ9555 as a control. We evaluated this system with two test antigens, the green fluorescent protein for initialin vitroassessment and theStreptococcus pneumoniaePspA protein for validation of our system in mice. All RASV strains expressing PspA generated high antilipopolysaccharide antibody titers, indicating that expression oflacIdid not interfere with the capacity to induce an immune response. Strain χ9241 induced significantly higher anti-PspA IgG and IgA antibody titers than strain χ9555, which expressed PspA constitutively. Anti-PspA antibody titers were inversely correlated to the level of LacI synthesis. Strain χ9241 also induced significantly greater protective efficacy against challenge with virulentS. pneumoniae. These results suggest that regulated delayed antigen synthesis is useful for improving immunogenicity of RASV strains.

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Mizumoto, Hiroyuki, Yuji Tomaru, Yoshitake Takao, Yoko Shirai y Keizo Nagasaki. "Diverse Responses of the Bivalve-Killing Dinoflagellate Heterocapsa circularisquama to Infection by a Single-Stranded RNA Virus". Applied and Environmental Microbiology 74, n.º 10 (21 de marzo de 2008): 3105–11. http://dx.doi.org/10.1128/aem.02190-07.

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ABSTRACT Viruses are believed to be significant pathogens for phytoplankton. Usually, they infect a single algal species, and often their infection is highly strain specific. However, the detailed molecular background of the strain specificity and its ecological significance have not been sufficiently understood. Here, we investigated the temporal changes in viral RNA accumulation and virus-induced cell lysis using a bloom-forming dinoflagellate Heterocapsa circularisquama and its single-stranded RNA virus, HcRNAV. We observed at least three host response patterns to virus inoculation: sensitive, resistant, and delayed lysis. In the sensitive response, the host cell culture was permissive for viral RNA replication and apparent cell lysis was observed; in contrast, resistant cell culture was nonpermissive for viral RNA replication and not lysed. In the delayed-lysis response, although viral RNA replication occurred, virus-induced cell lysis was faint and remarkably delayed. In addition, the number of infectious virus particles released to the culture supernatant at 12 days postinoculation was comparable to that of the sensitive strain. By further analysis, a few strains were characterized as variants of the delayed-lysis strain. These observations indicate that the response of H. circularisquama to HcRNAV infection is highly diverse.

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Parra, Araceli, Carmen Ponte, Carlos Cenjor, Carmen Martínez-Marín y Francisco Soriano. "Effect of Antibiotic Treatment Delay on Therapeutic Outcome of Experimental Acute Otitis Media Caused by Streptococcus pneumoniae Strains with Different Susceptibilities to Amoxicillin". Antimicrobial Agents and Chemotherapy 48, n.º 3 (marzo de 2004): 860–66. http://dx.doi.org/10.1128/aac.48.3.860-866.2004.

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ABSTRACT The effect of delayed administration of amoxicillin on the course of acute otitis media (AOM) caused by two Streptococcus pneumoniae strains with different susceptibilities to amoxicillin (MICs of 0.016 and 1 μg/ml for strains A and B, respectively) was evaluated in the gerbil model. The organisms were inoculated by transbullar challenge into the middle ear, and antibiotic treatment was administered at various times thereafter. The bacteriological and clinical efficacies of treatment diminished significantly with the delay of antibiotic administration. The bacterial eradication rates when antibiotic treatment was started at 2, 5, 8, 18, and 21 h post-bacterial inoculation were different for both strains (95, 95, 90, 55, and 55% for strain A and 95, 95, 65, 10, and 0% for strain B). Results of further experiments using strain B with higher antibiotic doses and numbers of administrations and different follow-up times indicate that the failures observed with the delayed administration were not related to the bacterial burden, selection of antibiotic-resistant mutants, or inadequate pharmacodynamic parameters. Such failures may be related to the metabolic bacterial status. The delayed amoxicillin treatment of AOM caused by S. pneumoniae may lead to therapeutic failures, mainly when organisms with diminished antibiotic susceptibility are involved.

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Shi, Huoying, Shifeng Wang y Roy Curtiss. "Evaluation of Regulated Delayed Attenuation Strategies for Salmonella enterica Serovar Typhi Vaccine Vectors in Neonatal and Infant Mice". Clinical and Vaccine Immunology 20, n.º 6 (24 de abril de 2013): 931–44. http://dx.doi.org/10.1128/cvi.00003-13.

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ABSTRACTWe developed regulated delayed attenuation strategies forSalmonellavaccine vectors. In this study, we evaluated the combination of these strategies in recombinant attenuatedSalmonella entericaserovar Typhi andSalmonella entericaserovar Typhimurium vaccine vectors with similar genetic backgroundsin vitroandin vivo. Our goal is to develop a vaccine to preventStreptococcus pneumoniaeinfection in newborns; thus, all strains delivered a pneumococcal antigen PspA and the impact of maternal antibodies was evaluated. The results showed that all strains with the regulated delayed attenuated phenotype (RDAP) displayed an invasive ability stronger than that of theS.Typhi vaccine strain, Ty21a, but weaker than that of their corresponding wild-type parental strains. The survival curves of different RDAP vaccine vectorsin vitroandin vivoexhibited diverse regulated delayed attenuation kinetics, which was different fromS.Typhi Ty21a and the wild-type parental strains. Under the influence of maternal antibody, the persistence of theS.Typhimurium RDAP strain displayed a regulated delayed attenuation trend in nasal lymphoid tissue (NALT), lung, and Peyer's patches, while the persistence ofS.Typhi RDAP strains followed the curve only in NALT. The bacterial loads ofS.Typhi RDAP strains were lower in NALT, lung, and Peyer's patches in mice born to immune mothers than in those born to naive mothers. In accordance with these results, RDAP vaccine strains induced high titers of IgG antibodies against PspA and againstSalmonellalipopolysaccharides. Immunization of mothers withS.Typhi RDAP strains enhanced the level of vaginal mucosal IgA, gamma interferon (IFN-γ), and interleukin 4 (IL-4) and resulted in a higher level of protection againstS. pneumoniaechallenge.

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Juárez-Rodríguez, María Dolores, Jiseon Yang, Rebin Kader, Praveen Alamuri, Roy Curtiss y Josephine E. Clark-Curtiss. "Live Attenuated Salmonella Vaccines Displaying Regulated Delayed Lysis and Delayed Antigen Synthesis To Confer Protection against Mycobacterium tuberculosis". Infection and Immunity 80, n.º 2 (5 de diciembre de 2011): 815–31. http://dx.doi.org/10.1128/iai.05526-11.

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ABSTRACTLive recombinant attenuatedSalmonellavaccine (RASV) strains have great potential to induce protective immunity againstMycobacterium tuberculosisby deliveringM. tuberculosisantigens. Recently, we reported that, in orally immunized mice, RASV strains delivering theM. tuberculosisearly secreted antigenic target 6-kDa (ESAT-6) protein and culture filtrate protein 10 (CFP-10) antigens via theSalmonellatype III secretion system (SopE amino-terminal region residues 1 to 80 with two copies of ESAT-6 and one copy of CFP-10 [SopENt80-E2C]) afforded protection against aerosol challenge withM. tuberculosis. Here, we constructed and evaluated an improvedSalmonellavaccine againstM. tuberculosis. We constructed translational fusions for the synthesis of two copies of ESAT-6 plus CFP-10 fused to the OmpC signal sequence (OmpCSS-E2C) and amino acids 44 to 338 of antigen 85A (Ag85A294) flanked by the signal sequence (SS) and C-terminal peptide (CT) of β-lactamase (BlaSS-Ag85A294-BlaCT) to enable delivery via theSalmonellatype II secretion system. The genes expressing these proteins were cloned as an operon transcribed from Ptrcinto isogenic Asd+/MurA+pYA3681 lysis vector derivatives with different replication origins (pBR, p15A, pSC101), resulting in pYA4890, pYA4891, and pYA4892 for SopENt80-E2C/Ag85A294synthesis and pYA4893 and pYA4894 for OmpCSS-E2C/Ag85A294synthesis. Mice orally immunized with the RASV χ11021 strain engineered to display regulated delayed lysis and regulated delayed antigen synthesisin vivoand harboring pYA4891, pYA4893, or pYA4894 elicited significantly greater humoral and cellular immune responses, and the RASV χ11021 strain afforded a greater degree of protection againstM. tuberculosisaerosol challenge in mice than RASVs harboring any other Asd+/MurA+lysis plasmid and immunization withM. bovisBCG, demonstrating that RASV strains displaying regulated delayed lysis with delayed antigen synthesis resulted in highly immunogenic delivery vectors for oral vaccination againstM. tuberculosisinfection.

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Biddle, F. G., S. A. Eden, J. S. Rossler y B. A. Eales. "Sex and death in the mouse: genetically delayed reproduction and senescence". Genome 40, n.º 2 (1 de abril de 1997): 229–35. http://dx.doi.org/10.1139/g97-032.

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A mammalian model of genetically postponed aging would be an important tool to test not only different mechanisms of aging but also the predictive value of various biomarkers of the aging process. Under conventional conditions, the historical strains of the laboratory mouse produce their first litter between 9 and 13 weeks of age and have a median time of death in their 2nd year. Our POSCH-2 strain, which was derived from wild-caught Mus musculus domesticus, produces its first litter in the current breeding generations at approximately 47 weeks of age and continues to breed throughout its 2nd and into its 3rd year of life. The aging curve of POSCH-2 has not yet been determined for economic reasons. Late onset of breeding is a characteristic of both females and males, but sexual maturity is more reliably assessed in females. The later breeding phenotype of POSCH-2 is genetically recessive to early breeding of the C57BL/6J historical laboratory strain and, since POSCH-2 females can be induced to ovulate at 8 weeks of age (but pregnancy does not result), the signal rather than the ovarian receptor to ovulate may be delayed. The genetically delayed reproduction and potentially longer life of the POSCH-2 strain appears to be a new trait in the mouse. The strain may be a useful mammalian model for aging studies and for the evaluation of antagonistic pleiotropy as a genetic model for the evolution of aging.Key words: delayed reproduction, senescence, aging, genetics, mouse.

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Montealegre, Constanza y Peter H. Graham. "Preference in the nodulation ofPhaseolus vulgariscv. RAB39. II. Effect of delayed inoculation or low cell representation in the inoculant on nodule occupancy byRhizobium tropiciUMR1899". Canadian Journal of Microbiology 42, n.º 8 (1 de agosto de 1996): 844–50. http://dx.doi.org/10.1139/m96-106.

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Common bean (Phaseolus vulgaris L.) is a traditional crop in much of Latin America, where it is often planted into soils containing numerous, sometimes ineffective, indigenous rhizobia. The presence of these indigenous organisms can limit response to inoculation. Because of this, we have sought bean cultivars that will nodulate preferentially with the inoculant strain, and have previously reported on the preference between the bean cultivar RAB39 and strains of Rhizobium tropici. We have detailed this interaction using the inoculant-quality strain UMR1899. In the present study the root tip marking (RTM) technique was used to demonstrate that this preference in nodulation was evident, even when inoculation with UMR1899 was delayed up to 8 relative to that with Rhizobium etli UMR1632. In contrast to studies with other legumes, roots of RAB39 were not predisposed to nodulate with UMR1632, even though preexposed to this strain for considerable periods of time. The presence of UMR1899 actually reduced nodulation by UMR1632 substantially, even when inoculation with UMR1899 was significantly delayed. When UMR1899 and UMR1632 were applied to separate halves of a split-root system, the number of nodules on the side receiving UMR1632 was less than for the half root inoculated with UMR1899, but the differences were not significant. This suggests that the preference response is not systemic but requires proximity between the strains involved. UMR1899 produced more than 50% of the nodules even when the ratio of UMR1632:UMR1899 in the inoculant was 10:1. The results are further evidence of a stable and marked preference of RAB39 for UMR1899, which warrants a more detailed study at the field level.Key words: Phaseolus vulgaris L., common bean, delayed inoculation, strain preference, cell proportions.

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Luong, Thanh T., Mei G. Lei y Chia Y. Lee. "Staphylococcus aureus Rbf Activates Biofilm Formation In Vitro and Promotes Virulence in a Murine Foreign Body Infection Model". Infection and Immunity 77, n.º 1 (27 de octubre de 2008): 335–40. http://dx.doi.org/10.1128/iai.00872-08.

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ABSTRACT We previously identified Rbf as an activator for biofilm formation on polystyrene surfaces in Staphylococcus aureus strain 8325-4. However, strain 8325-4 contains genetic mutations that may affect biofilm formation. To extend the observation to other strains, we used strain Newman, a weak biofilm producer, and strain UAMS-1, an osteomyelitis clinical strain, in this study. We found that mutations in the chromosomal rbf gene did not affect biofilm formation on polystyrene surfaces in these strains, but transformants of these strains carrying a multiple-copy plasmid containing the rbf gene formed stronger biofilms than the wild-type strains and the mutant strains. Using the flow cell method, we found that the chromosomal mutation in the rbf gene delayed biofilm formation, whereas strains with a plasmid containing the rbf gene accelerated biofilm formation in strains Newman and UAMS-1. These results led us to conclude that rbf is an activator of biofilm formation in different strains of S. aureus, although the degree of activation varies among strains. In a murine model of foreign body infection, the rbf mutations in strain Newman, but not in strain UAMS-1, reduced the bacterial survival rate in catheter lumen. However, UAMS-1 carrying multiple copies of rbf in a plasmid increased the bacterial survival rate. The animal studies therefore suggest that Rbf has a role in S. aureus virulence.

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Abriouel, Hikmate, Mercedes Maqueda, Antonio Gálvez, Manuel Martínez-Bueno y Eva Valdivia. "Inhibition of Bacterial Growth, Enterotoxin Production, and Spore Outgrowth in Strains of Bacillus cereus by Bacteriocin AS-48". Applied and Environmental Microbiology 68, n.º 3 (marzo de 2002): 1473–77. http://dx.doi.org/10.1128/aem.68.3.1473-1477.2002.

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ABSTRACT Bacteriocin AS-48 showed high bactericidal activity for mesophilic and psychrotrophic strains of Bacillus cereus over a broad pH range. AS-48 inhibition of the enterotoxin-producing strain LWL1 was enhanced by sodium nitrite, sodium lactate, and sodium chloride. The latter also enhanced AS-48 activity against strain CECT 131. Bacterial growth and enterotoxin production by strain LWL1 were completely inhibited at bacteriocin concentrations of 7.5 μg/ml. At subinhibitory bacteriocin concentrations, enterotoxin production decreased markedly and sporulation was delayed. Intact spores were resistant to AS-48 but became gradually sensitive to AS-48 during the course of germination.

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Aili, A., J. M. Torrenti, J. P. Sellin, J. F. Barthelemy y M. Vandamme. "On the long-term delayed strain of concrete structures". Cement and Concrete Research 165 (marzo de 2023): 107086. http://dx.doi.org/10.1016/j.cemconres.2022.107086.

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Collop, Andrew C., A. (Tom) Scarpas, Cor Kasbergen y Arian de Bondt. "Development and Finite Element Implementation of Stress-Dependent Elastoviscoplastic Constitutive Model with Damage for Asphalt". Transportation Research Record: Journal of the Transportation Research Board 1832, n.º 1 (enero de 2003): 96–104. http://dx.doi.org/10.3141/1832-12.

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The development and finite element (FE) implementation of a stress-dependent elastoviscoplastic constitutive model with damage for asphalt is described. The model includes elastic, delayed elastic, and viscoplastic components. The strains (and strain rates) for each component are additive, whereas they share the same stress (i.e., a series model). This formulation was used so that a stress-based nonlinearity and sensitivity to confinement could be introduced into the viscoplastic component without affecting the behavior of the elastic and delayed elastic components. A simple continuum damage mechanics formulation is introduced into the viscoplastic component to account for the effects of cumulative damage on the viscoplastic response of the material. The model is implemented in an incremental formulation into the CAPA-3D FE program developed at Delft University of Technology in the Netherlands. A local strain compatibility condition is utilized such that the incremental stresses are determined explicitly from the incremental strains at each integration point. The model is demonstrated by investigating the response of a semirigid industrial pavement structure subjected to container loading. Results show that the permanent vertical strains in the non-stress-dependent case are significantly lower than the permanent vertical strains in the stress-dependent case. Results also show that in the stress-dependent case, there is a more localized area of high permanent vertical compressive strain directly under the load at approximately halfdepth in the asphalt compared with the non-stress-dependent case, in which the distribution is more even.

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Setlow, Barbara, Kelly A. McGinnis, Katerina Ragkousi y Peter Setlow. "Effects of Major Spore-Specific DNA Binding Proteins on Bacillus subtilis Sporulation and Spore Properties". Journal of Bacteriology 182, n.º 24 (15 de diciembre de 2000): 6906–12. http://dx.doi.org/10.1128/jb.182.24.6906-6912.2000.

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ABSTRACT Sporulation of a Bacillus subtilis strain (termed α− β−) lacking the majority of the α/β-type small, acid-soluble spore proteins (SASP) that are synthesized in the developing forespore and saturate spore DNA exhibited a number of differences from that of the wild-type strain, including delayed forespore accumulation of dipicolinic acid, overexpression of forespore-specific genes, and delayed expression of at least one mother cell-specific gene turned on late in sporulation, although genes turned on earlier in the mother cell were expressed normally in α− β− strains. The sporulation defects in α− β− strains were corrected by synthesis of chromosome-saturating levels of either of two wild-type, α/β-type SASP but not by a mutant SASP that binds DNA poorly. Spores from α− β− strains also exhibited less glutaraldehyde resistance and slower outgrowth than did wild-type spores, but at least some of these defects in α− β− spores were abolished by the synthesis of normal levels of α/β-type SASP. These results indicate that α/β-type SASP may well have global effects on gene expression during sporulation and spore outgrowth.

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Ohtsu, Toshihiro, Ken Haruma, Yumiko Ide y Atsushi Takagi. "The Effect of Continuous Intake of Lactobacillus gasseri OLL2716 on Mild to Moderate Delayed Gastric Emptying: A Randomized Controlled Study". Nutrients 13, n.º 6 (28 de mayo de 2021): 1852. http://dx.doi.org/10.3390/nu13061852.

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Probiotics have been suggested to be effective for functional dyspepsia, but their effect on gastric motility is not clear. We evaluated the effect of Lactobacillus gasseri OLL2716 (LG21 strain) on mild to moderate delayed gastric emptying by a double-blind, parallel-group, placebo-controlled, randomized trial. Participants (n = 28) were randomly assigned to ingest LG21 strain-containing yogurt (LG21 strain group) or LG21 strain-free yogurt (placebo group) for 12 weeks. The 13C gastric emptying breath test was performed to measure the gastric emptying rate over time following ingestion of a liquid meal, and the time to reach the peak (Tmax) was used as an indicator of gastric emptying. We also measured the salivary amylase concentration, an indicator of autonomic dysfunction under stress. The per-protocol population (n = 27, male n = 4, female n = 23) was evaluated for efficacy. When a ≥30% reduction in the difference between participant’s Tmax and the Japanese mean Tmax was defined as an improvement, the odds ratio of improvement in delayed gastric emptying compared to placebo after 12 weeks was 4.1 (95% confidence interval, 0.8 to 20.2). Moreover, salivary amylase concentrations were significantly lower than in the placebo group, indicating an improvement in autonomic function. The present data were not enough to support the beneficial effects of the LG21 strain on delayed gastric emptying. However, if we define the odds ratio in further study investigated with a larger number of participants, LG21 strain might be expected to have some impact on delayed gastric emptying.

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Hopkins, D. L. "Biological Control of Pierce's Disease in the Vineyard with Strains of Xylella fastidiosa Benign to Grapevine". Plant Disease 89, n.º 12 (diciembre de 2005): 1348–52. http://dx.doi.org/10.1094/pd-89-1348.

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Naturally occurring strains of Xylella fastidiosa Wells et al. that were weakly virulent or aviru-lent to grapevine were inoculated into the lower internodes of Vitis vinifera L. cv. Carignane plants in the greenhouse and challenge inoculated with pathogenic strains 2 weeks later. Several strains provided some reduction in symptom development. Most effective in preventing or slowing the development of Pierce's disease in the greenhouse tests were a strain from sycamore and two from elderberry. In a 2-year test on ‘Himrod’ grape in the vineyard, strain Syc86-1 (from sycamore), but not strain PD-1 (from grapevine), was effective in limiting the development of Pierce's disease. In tests on new vineyard plantings of ‘Flame Seedless’ and ‘Cabernet Sauvi-gnon’, six strains of X. fastidiosa were evaluated for biological control of the natural progression of Pierce's disease. Only strain EB92-1 (from elderberry) provided good control of the disease in both Flame Seedless and Cabernet Sauvignon. Strain Syc86-1 was ineffective in these vineyard tests. Grape strain PD95-6 did lower disease severity in Flame Seedless when compared with nontreated vines, and grape strain PD91-2 delayed symptoms in Cabernet Sauvignon for 12 to 18 months. Biological control by inoculation of susceptible grapevines with benign strains of X. fastidiosa, especially strain EB92-1, appears to have the potential to control Pierce's disease in commercial vineyards in Florida and other areas where the disease occurs.

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Wedlock, D. Neil, Frank E. Aldwell, Desmond M. Collins, Geoffrey W. de Lisle, Theresa Wilson y Bryce M. Buddle. "Immune Responses Induced in Cattle by Virulent and AttenuatedMycobacterium bovis Strains: Correlation of Delayed-Type Hypersensitivity with Ability of Strains To Grow in Macrophages". Infection and Immunity 67, n.º 5 (1 de mayo de 1999): 2172–77. http://dx.doi.org/10.1128/iai.67.5.2172-2177.1999.

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ABSTRACT Comparison of immune responses induced in cattle by virulent and attenuated strains of Mycobacterium bovis will assist in identifying responses associated with resistance or susceptibility to disease. Four strains of M. bovis, one which is virulent in guinea pigs (WAg201) and three which are attenuated in guinea pigs (an isoniazid-resistant strain [WAg405], ATCC 35721, and BCG) were compared for their abilities to induce immune responses in cattle and to grow in bovine lung alveolar macrophage cultures. Extensive macroscopic lesions were found only in cattle inoculated with the virulent M. bovis strain. Strong antibody responses toM. bovis culture filtrate, as well as persistently high levels of gamma interferon and interleukin-2 released from purified protein derivative (PPD)-stimulated peripheral blood lymphocyte cultures, were observed in the cattle inoculated with the virulent strain compared to those inoculated with the attenuated strains. All cattle inoculated with the virulent strain or two of the attenuated strains (WAg405 and ATCC 35721) elicited strong delayed-type hypersensitivity responses to PPD in skin tests, while animals inoculated with BCG induced only a weak response. The three strains which produced strong skin test responses proliferated well in bovine alveolar macrophages and induced high levels of proinflammatory cytokine mRNAs compared to BCG. Our study showed that skin test responsiveness to PPD correlated with the ability of the strains to grow in alveolar macrophages rather than to their pathogenicity in cattle.

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Yasuda, Shumpei P., Yuki Miyasaka, Xuehan Hou, Yo Obara, Hiroshi Shitara, Yuta Seki, Kunie Matsuoka et al. "Two Loci Contribute to Age-Related Hearing Loss Resistance in the Japanese Wild-Derived Inbred MSM/Ms Mice". Biomedicines 10, n.º 9 (7 de septiembre de 2022): 2221. http://dx.doi.org/10.3390/biomedicines10092221.

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An MSM/Ms strain was established using Japanese wild mice, which exhibit resistance to several phenotypes associated with aging, such as obesity, inflammation, and tumorigenesis, compared to common inbred mouse strains. MSM/Ms strain is resistant to age-related hearing loss, and their auditory abilities are sustained for long durations. The age-related hearing loss 3 (ahl3) locus contributes to age-related hearing in MSM/Ms strain. We generated ahl3 congenic strains by transferring a genomic region on chromosome 17 from MSM/Ms mice into C57BL/6J mice. Although C57BL/6J mice develop age-related hearing loss because of the ahl allele of the cadherin 23 gene, the development of middle- to high-frequency hearing loss was significantly delayed in an ahl3 congenic strain. Moreover, the novel age-related hearing loss 10 (ahl10) locus associated with age-related hearing resistance in MSM/Ms strain was mapped to chromosome 12. Although the resistance effects in ahl10 congenic strain were slightly weaker than those in ahl3 congenic strain, slow progression of age-related hearing loss was confirmed in ahl10 congenic strain despite harboring the ahl allele of cadherin 23. These results suggest that causative genes and polymorphisms of the ahl3 and ahl10 loci are important targets for the prevention and treatment of age-related hearing loss.

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ia Chen, Dan y Zhiting Xu. "Global dynamics of a delayed diffusive two-strain disease model". Differential Equations & Applications, n.º 1 (2016): 99–122. http://dx.doi.org/10.7153/dea-08-07.

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Cole, Andrew. "Influenza vaccine is delayed by problems in growing virus strain". BMJ 333, n.º 7571 (5 de octubre de 2006): 721.2. http://dx.doi.org/10.1136/bmj.333.7571.721-a.

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Etchebar, Christophe, Danièle Trigalet-Demery, Frédérique van Gijsegem, Jacques Vasse y André Trigalet. "Xylem Colonization by an HrcV¯ Mutant of Ralstonia solanacearum Is a Key Factor for the Efficient Biological Control of Tomato Bacterial Wilt". Molecular Plant-Microbe Interactions® 11, n.º 9 (septiembre de 1998): 869–77. http://dx.doi.org/10.1094/mpmi.1998.11.9.869.

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Microscopic studies of the colonization of the vascular tissues of tomato by an HrcV¯ (formerly HrpO¯) mutant strain of Ralstonia solanacearum were carried out after either root inoculation of the mutant strain alone or delayed challenge inoculation by a pathogenic strain. The use of two different marker genes, lacZ and uidA, introduced into either mutant or wild-type strains, respectively, permitted histological observation for the presence of both strains simultaneously. In roots, both strains could be found together in infected root tips and in lateral root emergence sites (lateral root cracks), but these bacterial strains subsequently invaded separate xylem vessels in the root system. At the hypocotyl level, a novel staining procedure, in conjunction with bacterial isolation and counting, showed three vascular colonization patterns: exclusive colonization by each of the competitors or simultaneous presence of each strain in separate xylem vessels. The relative frequencies of these patterns depended upon the root inoculation techniques used. The presence of one population always influenced the density of the other challenge-inoculated population. In plants inoculated with both wild-type and mutant strains, the population of the wild-type strain is lower than in plants inoculated with the wild type alone. In contrast, growth of the HrcV¯ mutant strain was significantly increased in the presence of the pathogenic strain. Two agriculturally acceptable techniques for plant inoculation were tested. Inoculation of plants by transplanting them into soil amended with clay micro-granules impregnated with the HrcV¯ mutant strain gave higher and more reproducible colonization of the plants than inoculation by watering a bacterial suspension on the roots. Significant percentages of exclusive colonization by the HrcV¯ mutant strain were only obtained after the clay microgranule inoculation technique. Competition for space in xylem vessels is one of the possible explanations for the protective ability of the HrcV¯ mutant strain against subsequent invasion by a pathogenic strain.

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Reifsnyder, Peter C., Austen Te y David E. Harrison. "Differential Effects of Rapamycin on Glucose Metabolism in Nine Inbred Strains". Journals of Gerontology: Series A 75, n.º 1 (4 de julio de 2019): 50–57. http://dx.doi.org/10.1093/gerona/glz157.

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Abstract Studies in mice suggest that rapamycin has a negative impact on glucose homeostasis by inducing insulin resistance. However, results have been inconsistent and difficult to assess because the strains, methods of treatment, and analysis vary among studies. Using a consistent protocol, we surveyed nine inbred strains of mice for the effect of rapamycin on various aspects of glucose metabolism. Across all strains, rapamycin significantly delayed glucose clearance after challenge. However, rapamycin showed no main effect on systemic insulin sensitivity. Analysis of individual strains shows that rapamycin induced higher glucose values at 15 minutes post-challenge in 7/9 strains. However, only three strains show rapamycin-induced reduction in glucose clearance from 15 to 120 minutes. Although pancreatic insulin content was reduced by rapamycin in seven strains, none showed reduced serum insulin values. Although one strain showed no effects of rapamycin on glucose metabolism (129), another showed increased systemic insulin sensitivity (B6). We suggest that rapamycin likely inhibits insulin production and secretion in most strains while having strain-specific effects on glucose clearance without altering systemic insulin sensitivity. This strain survey indicates that genetic differences greatly influence the metabolic response to rapamycin.

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Derckel, Jean-Paul, Fabienne Baillieul, Sébastien Manteau, Jean-Claude Audran, Bernard Haye, Bernard Lambert y Laurent Legendre. "Differential Induction of Grapevine Defenses by Two Strains of Botrytis cinerea". Phytopathology® 89, n.º 3 (marzo de 1999): 197–203. http://dx.doi.org/10.1094/phyto.1999.89.3.197.

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Even though Botrytis cinerea, the causal agent of gray mold, is a highly variable fungus with strains displaying very different degrees of virulence toward one given host plant species, no study has yet shown any correlation between the lack of aggressiveness of one given strain and its ability to stimulate a defense response from its host. Strains of B. cinerea collected from different host plant species were screened for their pathogenicity on grapevine to select two strains with similar morphological characteristics but different levels of virulence. In grapevine leaves, the less aggressive strain, T4, enhanced the accumulation of many defense products including secondary metabolites and the pathogenesis-related proteins, chitinase and β-1,3-glucanase. Interestingly, secondary metabolites were formed in cells around a small group of dead cells. When compared with T4, the more aggressive strain, T8, had larger necrotic spots, no secondary metabolite biosynthesis, and accumulations of chitinases and β-1,3-glucanases that were more delayed, yet only slightly weaker. The culture fluids of both strains mimicked the differential effect of each isolate in stimulating chitinase activity when infiltrated into grapevine leaves.

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Wang, Shifeng, Huoying Shi, Yuhua Li, Zhaoxing Shi, Xin Zhang, Chang-Ho Baek, Tabor Mothershead y Roy Curtiss. "A Colanic Acid Operon Deletion Mutation Enhances Induction of Early Antibody Responses by Live Attenuated Salmonella Vaccine Strains". Infection and Immunity 81, n.º 9 (17 de junio de 2013): 3148–62. http://dx.doi.org/10.1128/iai.00097-13.

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ABSTRACTColanic acid (CA) is a common exopolysaccharide produced by many genera in theEnterobacteriaceae. It is critical for biofilm formation on HEp-2 cells and on chicken intestinal tissue bySalmonella. In this study, we generated different CA synthesis gene mutants and evaluated the immune responses induced by these mutants. One of these mutations, Δ(wza-wcaM)8, which deleted the whole operon for CA synthesis, was introduced into twoSalmonellavaccine strains attenuated by auxotrophic traits or by the regulated delayed attenuation strategy (RDAS). The mice immunized with the auxotrophicSalmonellavaccine strain with the deletion mutation Δ(wza-wcaM)8developed higher vaginal IgA titers against the heterologous protective antigen and higher levels of antigen-specific IgA secretion cells in lungs. InSalmonellavaccine strains with RDAS, the strain with the Δ(wza-wcaM)8mutation resulted in higher levels of protective antigen production duringin vitrogrowth. Mice immunized with this strain developed higher serum IgG and mucosal IgA antibody responses at 2 weeks. This strain also resulted in better gamma interferon (IFN-γ) responses than the strain without this deletion at doses of 108and 109CFU. Thus, the mutation Δ(wza-wcaM)8will be included in various recombinant attenuatedSalmonellavaccine (RASV) strains with RDAS derived fromSalmonella entericaserovar Paratyphi A andSalmonella entericaserovar Typhi to induce protective immunity against bacterial pathogens.

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Feng, Jia-Xun, Zhi-Zhong Song, Cheng-Jie Duan, Shuai Zhao, Ying-Qiao Wu, Chao Wang, J. Maxwell Dow y Ji-Liang Tang. "The xrvA gene of Xanthomonas oryzae pv. oryzae, encoding an H-NS-like protein, regulates virulence in rice". Microbiology 155, n.º 9 (1 de septiembre de 2009): 3033–44. http://dx.doi.org/10.1099/mic.0.028910-0.

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Xanthomonas oryzae pv. oryzae (Xoo) causes bacterial blight disease in rice, one of the most serious rice diseases. The xrvA gene from Xoo strain 13751 encodes a protein containing a histone-like nucleoid-structuring protein (H-NS) domain. The expression of xrvA in strain 13751 was enhanced in XOM2 minimal medium. Mutation of the xrvA gene of strain 13751 led to a significant reduction in virulence in the host plant rice, a delayed hypersensitive response in the nonhost castor-oil plant, a decrease in extracellular polysaccharide and diffusible signal factor production, and an increase in intracellular glycogen accumulation. Northern hybridization analyses revealed that the virulence-associated genes hrpG, hrpX, rpfC, rpfF, rpfG and gumB were downregulated in the xrvA mutant compared to the wild-type and complemented strains. Interestingly, increase of copy number of xrvA in the wild-type strain 13751 resulted in a strain showing similar phenotypes as the xrvA mutant and a reduction of the expression of gumB, hrpX, rpfC, rpfF and rpfG. These findings indicate that the xrvA gene, which is highly conserved in the sequenced strains of Xanthomonas, encodes an important regulatory factor for the virulence of Xoo.

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24

González, Laura, Álvaro Gaute, Jokin Rico y Carlos Thomas. "Effect of Fibre Reinforcement on Creep in Early Age Concrete". Applied Sciences 12, n.º 1 (28 de diciembre de 2021): 257. http://dx.doi.org/10.3390/app12010257.

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This research analyses the strain behaviour of fibre-reinforced concrete (FRC) in the event of a creep episode. The analysis of creep experienced by FRC specimens during the test reflects better performance than that predicted by the EHE-08 standard. The authors propose a formulation for the evaluation of creep strain undergone by FRC. During the research, the evolution of the modulus of elasticity of FRC after a creep episode is analysed. After the test campaign, it can be concluded that FRC loaded at an earlier age stiffens after a creep episode. After the creep test is completed, the delayed elastic strain undergone by FRC is analysed and it is observed that FRC loaded at an earlier age undergoes less deformation. The authors propose a formulation for the evaluation of the delayed elastic strain undergone by FRC after a creep episode.

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25

Scibilia, K. L., F. V. Hebard y L. Shain. "Conidia of hypovirulent strains of Cryphonectriaparasitica differ in their potential for biocontrol of chestnut blight". Canadian Journal of Forest Research 22, n.º 9 (1 de septiembre de 1992): 1338–42. http://dx.doi.org/10.1139/x92-178.

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Conidia from eight hypovirulent strains of Cryphonectriaparasitica (Murr.) Barr were suspended in water and applied to the bark of American chestnut (Castaneadentata (Marsh.) Borkh.) trees. Cankers were initiated with mycelium of virulent strains isogenic to the applied conidia. Hypovirulent strains differed significantly in the ability of their conidia to putatively convert isogenic virulent strains in cankers, as indicated by the recovery of cultures with hypovirulent morphology from challenged cankers. A tank mix of conidia from two hypovirulent strains in different conversion groups putatively converted significantly more cankers initiated by isogenic virulent strains than did separate applications of conidia from these strains, particularly when the second application was delayed by 2 weeks. Cankers initiated on excised stems with virulent strain Ep 155 (American Type Culture Collection 38755) yielded cultures with hypovirulent morphology after application of conidia from isogenic hypovirulent strain Ep 780 at densities as low as 50 and 700 conidia/cm2 for inoculations sealed or not sealed with latex caulk, respectively.

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26

Wang, Shaoli, Achun Zhang y Fei Xu. "Dynamical analysis for delayed virus infection models with cell-to-cell transmission and density-dependent diffusion". International Journal of Biomathematics 13, n.º 07 (20 de agosto de 2020): 2050060. http://dx.doi.org/10.1142/s1793524520500606.

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In this paper, certain delayed virus dynamical models with cell-to-cell infection and density-dependent diffusion are investigated. For the viral model with a single strain, we have proved the well-posedness and studied the global stabilities of equilibria by defining the basic reproductive number [Formula: see text] and structuring proper Lyapunov functional. Moreover, we found that the infection-free equilibrium is globally asymptotically stable if [Formula: see text], and the infection equilibrium is globally asymptotically stable if [Formula: see text]. For the multi-strain model, we found that all viral strains coexist if the corresponding basic reproductive number [Formula: see text], while virus will extinct if [Formula: see text]. As a result, we found that delay and the density-dependent diffusion does not influence the global stability of the model with cell-to-cell infection and homogeneous Neumann boundary conditions.

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27

Alexandrova, Natalya A., Maya I. Zaslavskaya, Irina V. Soloveva, Anna G. Tochilina y Irina V. Belova. "EVALUATION OF ANTI-CANDIDA ACTIVITY OF METABOLITES OF ENTEROCOCCAL CLINICAL ISOLATES". Russian Clinical Laboratory Diagnostics 64, n.º 11 (15 de noviembre de 2019): 690–92. http://dx.doi.org/10.18821/0869-2084-2019-64-11-690-692.

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When studying the effect of the metabolic products of clinical isolates of enterococci on the viability of Candida albicans, it was found that metabolites of all tested strains of Enterococcus faecium, E. faecalis had a fungistatic effect. At the same time a reliable fungicidal effect is a strain-specific feature. It is better to use the method of delayed antagonism on double-layer agar to assess the antifungal effect of enterococcal metabolism products.

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28

Minz Dub, Anna, Leonie Kokkelink, Bettina Tudzynski, Paul Tudzynski y Amir Sharon. "Involvement of Botrytis cinerea Small GTPases BcRAS1 and BcRAC in Differentiation, Virulence, and the Cell Cycle". Eukaryotic Cell 12, n.º 12 (4 de octubre de 2013): 1609–18. http://dx.doi.org/10.1128/ec.00160-13.

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ABSTRACTSmall GTPases of the Ras superfamily are highly conserved proteins that are involved in various cellular processes, in particular morphogenesis, differentiation, and polar growth. Here we report on the analysis of RAS1 and RAC homologues from the gray mold fungusBotrytis cinerea. We show that these small GTPases are individually necessary for polar growth, reproduction, and pathogenicity, required for cell cycle progression through mitosis (BcRAC), and may lie upstream of the stress-related mitogen-activated protein kinase (MAPK) signaling pathway.bcras1andbcracdeletion strains had reduced growth rates, and their hyphae were hyperbranched and deformed. In addition, both strains were vegetatively sterile and nonpathogenic. A strain expressing a constitutively active (CA) allele of the BcRAC protein had partially similar but milder phenotypes. Similar to the deletion strains, the CA-BcRAC strain did not produce any conidia and had swollen hyphae. In contrast to the two deletion strains, however, the growth rate of the CA-BcRAC strain was normal, and it caused delayed but well-developed disease symptoms. Microscopic examination revealed an increased number of nuclei and disturbance of actin localization in the CA-BcRAC strain. Further work with cell cycle- and RAC-specific inhibitory compounds associated the BcRAC protein with progression of the cell cycle through mitosis, possibly via an effect on microtubules. Together, these results show that the multinucleate phenotype of the CA-BcRAC strain could result from at least two defects: disruption of polar growth through disturbed actin localization and uncontrolled nuclear division due to constitutive activity of BcRAC.

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Lv, Huibin, Ray T. Y. So, Qi Wen Teo, Meng Yuan, Hejun Liu, Chang-Chun D. Lee, Garrick K. Yip et al. "Neutralizing Antibody Response to Sarbecovirus Is Delayed in Sequential Heterologous Immunization". Viruses 14, n.º 7 (24 de junio de 2022): 1382. http://dx.doi.org/10.3390/v14071382.

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Antigenic imprinting, which describes the bias of the antibody response due to previous immune history, can influence vaccine effectiveness. While this phenomenon has been reported for viruses such as influenza, there is little understanding of how prior immune history affects the antibody response to SARS-CoV-2. This study provides evidence for antigenic imprinting through immunization with two Sarbecoviruses, the subgenus that includes SARS-CoV-2. Mice were immunized subsequently with two antigenically distinct Sarbecovirus strains, namely SARS-CoV-1 and SARS-CoV-2. We found that sequential heterologous immunization induced cross-reactive binding antibodies for both viruses and delayed the emergence of neutralizing antibody responses against the booster strain. Our results provide fundamental knowledge about the immune response to Sarbecovirus and important insights into the development of pan-sarbecovirus vaccines and guiding therapeutic interventions.

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Cazalets, Jean-René, Marie Gardette y Gérard Hilaire. "Locomotor Network Maturation Is Transiently Delayed in the MAOA-Deficient Mouse". Journal of Neurophysiology 83, n.º 4 (1 de abril de 2000): 2468–70. http://dx.doi.org/10.1152/jn.2000.83.4.2468.

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In vivo and in vitro experiments were performed in control (C3H) and monoamine oxidase A (MAOA)-deficient (Tg8) neonatal mice to determine whether MAOA deficiency affected spinal locomotor network maturation. Comparing the swimming behaviors at birth in C3H mice with those in Tg8 mice revealed a delayed role for the hindlimbs in Tg8 swimming, even though adult swimming behavior was acquired at postnatal day 14 (P14) in both strains. Analyzing the locomotor network activity in vitro showed that serotonin (5-HT) induced and modulated locomotor-like discharges in hindlimb ventral roots of C3H but not Tg8 neonates. The Tg8 network began, however, to be affected by 5-HT at P11. Thus both in vivo and in vitro results argue for a transient delay of locomotor network maturation in the Tg8 strain.

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Harrison, Judith, Alexandre Jamet, Cecilia I. Muglia, Ghislaine Van de Sype, O. Mario Aguilar, Alain Puppo y Pierre Frendo. "Glutathione Plays a Fundamental Role in Growth and Symbiotic Capacity of Sinorhizobium meliloti". Journal of Bacteriology 187, n.º 1 (1 de enero de 2005): 168–74. http://dx.doi.org/10.1128/jb.187.1.168-174.2005.

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ABSTRACT Rhizobia form a symbiotic relationship with plants of the legume family to produce nitrogen-fixing root nodules under nitrogen-limiting conditions. We have examined the importance of glutathione (GSH) during free-living growth and symbiosis of Sinorhizobium meliloti. An S. meliloti mutant strain (SmgshA) which is unable to synthesize GSH due to a gene disruption in gshA, encoding the enzyme for the first step in the biosynthesis of GSH, was unable to grow under nonstress conditions, precluding any nodulation. In contrast, an S. meliloti strain (SmgshB) with gshB, encoding the enzyme involved in the second step in GSH synthesis, deleted was able to grow, indicating that γ-glutamylcysteine, the dipeptide intermediate, can partially substitute for GSH. However, the SmgshB strain showed a delayed-nodulation phenotype coupled to a 75% reduction in the nitrogen fixation capacity. This phenotype was linked to abnormal nodule development. Both the SmgshA and SmgshB mutant strains exhibited higher catalase activity than the wild-type S. meliloti strain, suggesting that both mutant strains are under oxidative stress. Taken together, these results show that GSH plays a critical role in the growth of S. meliloti and during its interaction with the plant partner.

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Kaymakamzade, Bilgen y Evren Hincal. "Two-strain epidemic model with two vaccinations and two time delayed". Quality & Quantity 52, S1 (9 de noviembre de 2017): 695–709. http://dx.doi.org/10.1007/s11135-017-0647-8.

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Chen, Zhenwu y Zhiting Xu. "A delayed diffusive influenza model with two-strain and two vaccinations". Applied Mathematics and Computation 349 (mayo de 2019): 439–53. http://dx.doi.org/10.1016/j.amc.2018.12.065.

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Bubeck, Sarah S., Angelene M. Cantwell y Peter H. Dube. "Delayed Inflammatory Response to Primary Pneumonic Plague Occurs in Both Outbred and Inbred Mice". Infection and Immunity 75, n.º 2 (13 de noviembre de 2006): 697–705. http://dx.doi.org/10.1128/iai.00403-06.

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ABSTRACT Yersinia pestis is the causative agent of plague, a disease that can manifest as either bubonic or pneumonic plague. An interesting feature of plague is that it is a rapidly progressive disease, suggesting that Y. pestis either evades and/or suppresses the innate immune response to infection. Therefore, the early host response during the course of primary pneumonic plague was investigated in two mouse strains, the outbred strain CD1 and the inbred strain C57BL/6. A comparative analysis of the course of disease in these two strains of mice indicated that they are susceptible to intranasal Y. pestis CO92 infection and have similar 50% lethal doses and kinetics of infection with respect to colonization of the lung, liver, and spleen. Significantly, in both strains of mice, robust neutrophil recruitment to the lungs was not observed until 48 h after infection, suggesting that there was a delay in inflammatory cell recruitment to the site of infection. In addition, proinflammatory cytokines (interleukin-6 [IL-6], tumor necrosis factor alpha, gamma interferon, IL-12p70, monocyte chemoattractant protein 1) and chemokines (KC, MIP-2) in the bronchoalveolar lavage fluids were not readily detected until 48 h after infection, which coincided with the increase in polymorphonuclear leukocyte (PMN) recruitment to the lungs. In comparison, CD1 mice with gram-negative pneumonia caused by Klebsiella pneumoniae exhibited strong inflammatory responses early in infection, with PMNs comprising the majority of the cells in the bronchoalveolar lavage fluid 24 h postinfection, indicating that PMN recruitment to the lungs could occur earlier in this infection than in Y. pestis infection. Together, our results indicate that there is a delay in the recruitment of neutrophils to the lungs in the mouse model of primary plague pneumonia that correlates with delayed expression of proinflammatory cytokines and chemokines in both outbred and inbred mice.

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Puzrin, Alexander M., Thierry Faug y Itai Einav. "The mechanism of delayed release in earthquake-induced avalanches". Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 475, n.º 2227 (julio de 2019): 20190092. http://dx.doi.org/10.1098/rspa.2019.0092.

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Snow avalanches can be triggered by strong earthquakes. Most existing models assume that snow slab avalanches happen simultaneously during or immediately after their triggering. Therefore, they cannot explain the plausibility of delayed avalanches that are released minutes to hours after a quake. This paper establishes the basic mechanism of delays in earthquake-induced avalanche release using a novel analytical model that yields dynamics consistent with three documented cases, including two from Western Himalaya and one from central Italy. The mechanism arises from the interplay between creep, strain softening and strain-rate sensitivity of snow, which drive the growth of a basal shear fracture. Our model demonstrates that earthquake-triggered delayed avalanches are rare, yet possible, and could lead to significant damage, especially in long milder slopes. The generality of the model formulation opens a new approach for exploring many other problems related to natural slab avalanche release.

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Podrzaj, Lucija, Johanna Burtscher, Franziska Küller y Konrad J. Domig. "Strain-Dependent Cheese Spoilage Potential of Clostridium tyrobutyricum". Microorganisms 8, n.º 11 (22 de noviembre de 2020): 1836. http://dx.doi.org/10.3390/microorganisms8111836.

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Clostridium tyrobutyricum, a Gram-positive, anaerobic, spore-forming bacterium, is considered as one of the main causative agents for spoilage of hard and semihard cheeses. Growth of C. tyrobutyricum in cheese is critically influenced by ripening temperature and time, pH, salt and lactic acid concentration, moisture and fat content, and the presence of other microorganisms. Previous studies revealed high intraspecies diversity of C. tyrobutyricum strains and variable tolerance toward pH, temperatures, and salt concentrations. These findings indicate that strain-dependent characteristics may be relevant to assess the risk for cheese spoilage if clostridial contamination occurs. In this study, we aimed to compare the phenotypes of 12 C. tyrobutyricum strains which were selected from 157 strains on the basis of genotypic and proteotypic variability. The phenotypic analysis comprised the assessment of gas production and organic acid concentrations in an experimental cheese broth incubated at different temperatures (37, 20, and 14 °C). For all tested strains, delayed gas production at lower incubation temperatures and a strong correlation between gas production and the change in organic acid concentrations were observed. However, considering the time until gas production was visible at different incubation temperatures, a high degree of heterogeneity was found among the tested strains. In addition, variation among replicates of the same strain and differences due to different inoculum levels became evident. This study shows, that, among other factors, strain-specific germination and growth characteristics should be considered to evaluate the risk of cheese spoilage by C. tyrobutyricum.

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Morgan, Sydney C., Jade J. Haggerty, Britney Johnston, Vladimir Jiranek y Daniel M. Durall. "Response to Sulfur Dioxide Addition by Two Commercial Saccharomyces cerevisiae Strains". Fermentation 5, n.º 3 (27 de julio de 2019): 69. http://dx.doi.org/10.3390/fermentation5030069.

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Sulfur dioxide (SO2) is an antioxidant and antimicrobial agent used in winemaking. Its effects on spoilage microorganisms has been studied extensively, but its effects on commercial Saccharomyces cerevisiae strains, the dominant yeast in winemaking, require further investigation. To our knowledge, no previous studies have investigated both the potential SO2 resistance mechanisms of commercial yeasts as well as their production of aroma-active volatile compounds in response to SO2. To study this, fermentations of two commercial yeast strains were conducted in the presence (50 mg/L) and absence (0 mg/L) of SO2. Strain QA23 was more sensitive to SO2 than Strain BRL97, resulting in delayed cell growth and slower fermentation. BRL97 exhibited a more rapid decrease in free SO2, a higher initial production of hydrogen sulfide, and a higher production of acetaldehyde, suggesting that each strain may utilize different mechanisms of sulfite resistance. SO2 addition did not affect the production of aroma-active volatile compounds in QA23, but significantly altered the volatile profiles of the wines fermented by BRL97.

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Cheville, Norman F., Allen E. Jensen, David C. Morfitt y Thomas J. Stabel. "Cutaneous delayed hypersensitivity reactions of cattle vaccinated with mutant strains of Brucella abortus, using brucellins prepared from various brucellar strains". American Journal of Veterinary Research 55, n.º 9 (1 de septiembre de 1994): 1261–66. http://dx.doi.org/10.2460/ajvr.1994.55.09.1261.

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Summary Cutaneous reactivity to brucellin was evaluated in 10-month-old heifers vaccinated with low-virulence mutant strains of Brucella abortus and was compared with brucellin reactions in postparturient cows with active brucellosis. In the cows, the cutaneous lesion was characterized microscopically as severe, acute, serofibrinous vasculitis; dermal lesions at 6, 12, 25, and 48 hours after brucellin injection consisted of endothelial activation and perivascular exudation that led to progressive accumulation of fibrin, monocytes, macrophages, and lymphocytes. In vaccinated heifers, cutaneous tests were done, using standard brucellin, brucellin prepared from strain RB51, and the purified brucellar proteins-31K and superoxide dismutase. Negative-control cattle given saline solution, did not have cutaneous reactions. Standard brucellin induced the most marked reactions in vaccinated heifers. Brucellin from rough strain RB51 caused positive reactions in heifers vaccinated with strain 19, but reactions were variable in other groups. Skin lesions induced by purified superoxide dismutase and 31-kd proteins in vaccinated cattle were not acceptable for diagnosis. Marked variability of test responses in vaccinated cattle precludes field use of this test to determine vaccination status.

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Oliveira, Fernanda Bellaniza Caminha de, Vanessa Paola Alves Sampaio de Sá Freire, Sharton Vinicius Antunes Coelho, Lana Monteiro Meuren, Julys da Fonseca Palmeira, Ana Luísa Cardoso, Francisco de Assis Rocha Neves et al. "ZIKV Strains Elicit Different Inflammatory and Anti-Viral Responses in Microglia Cells". Viruses 15, n.º 6 (26 de mayo de 2023): 1250. http://dx.doi.org/10.3390/v15061250.

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In recent years, the Zika Virus (ZIKV) has caused pandemic outbreaks associated with a high rate of congenital ZIKV syndrome (CZS). Although all strains associated with worldwide outbreaks derive from the Asian lineage, the reasons for their enhanced spread and severity are not fully understood. In this study, we conducted a comparative analysis of miRNAs (miRNA-155/146a/124) and their cellular targets (SOCS1/3, SHP1, TRAF6, IRAK1), as well as pro- and anti-inflammatory and anti-viral cytokines (IL-6, TNF-α, IFN-γ, IL-10, and IFN-β) and peroxisome proliferator-activated receptor γ (PPAR-γ) expression in BV2 microglia cells infected with ZIKV strains derived from African and Asian lineages (ZIKVMR766 and ZIKVPE243). BV2 cells were susceptible to both ZIKV strains, and showed discrete levels of viral replication, with delayed release of viral particles without inducing significant cytopathogenic effects. However, the ZIKVMR766 strain showed higher infectivity and replicative capacity, inducing a higher expression of microglial activation markers than the ZIKVPE243 strain. Moreover, infection with the ZIKVMR766 strain promoted both a higher inflammatory response and a lower expression of anti-viral factors compared to the ZIKVPE243 strain. Remarkably, the ZIKKPE243 strain induced significantly higher levels of the anti-inflammatory nuclear receptor—PPAR-γ. These findings improve our understanding of ZIKV-mediated modulation of inflammatory and anti-viral innate immune responses and open a new avenue to explore underlining mechanisms involved in the pathogenesis of ZIKV-associated diseases.

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Kong, Qingke, Qing Liu, Kenneth L. Roland y Roy Curtiss. "Regulated Delayed Expression of rfaH in an Attenuated Salmonellaenterica Serovar Typhimurium Vaccine Enhances Immunogenicity of Outer Membrane Proteins and a Heterologous Antigen". Infection and Immunity 77, n.º 12 (5 de octubre de 2009): 5572–82. http://dx.doi.org/10.1128/iai.00831-09.

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ABSTRACT RfaH is a transcriptional antiterminator that reduces the polarity of long operons encoding secreted and surface-associated cell components of Salmonella enterica serovar Typhimurium, including O antigen and lipopolysaccharide core sugars. A ΔrfaH mutant strain is attenuated in mice (50% lethal dose [LD50], >108 CFU). To examine the potential for using rfaH in conjunction with other attenuating mutations, we designed a series of strains in which we replaced the native rfaH promoter with the tightly regulated arabinose-dependent araC PBAD promoter so that rfaH expression was dependent on exogenously supplied arabinose provided during in vitro growth. Following colonization of host lymphoid tissues, where arabinose was not available, the PBAD promoter was no longer active and rfaH was not expressed. In the absence of RfaH, O antigen and core sugars were not synthesized. We constructed three mutant strains that expressed different levels of RfaH by altering the ribosome-binding sequence and start codon. One mutation, ΔPrfaH178, was introduced into the attenuated vaccine strain χ9241 (ΔpabA ΔpabB ΔasdA) expressing the pneumococcal surface protein PspA from an Asd+ balanced-lethal plasmid. Mice immunized with this strain and boosted 4 weeks later induced higher levels of serum immunoglobulin G specific for PspA and for outer membrane proteins from other enteric bacteria than either an isogenic ΔrfaH derivative or the isogenic RfaH+ parent. Eight weeks after primary oral immunization, mice were challenged with 200 LD50 of virulent S treptococcus pneumoniae WU2. Immunization with ΔPrfaH178 mutant strains led to increased levels of protection compared to that of the parent χ9241 and of a ΔrfaH derivative of χ9241.

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Rotem, Shahar, Erez Bar-Haim, Hila Cohen, Uri Elia, Raphael Ber, Avigdor Shafferman y Ofer Cohen. "Consequences of Delayed Ciprofloxacin and Doxycycline Treatment Regimens against Francisella tularensis Airway Infection". Antimicrobial Agents and Chemotherapy 56, n.º 10 (30 de julio de 2012): 5406–8. http://dx.doi.org/10.1128/aac.01104-12.

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ABSTRACTThis study examines the efficacy, bacterial load, and humoral response of extensively delayed ciprofloxacin or doxycycline treatments following airway exposure of mice toFrancisella tularensissubsp.holarctica(strain LVS) or to the highly virulentF. tularensissubsp.tularensis(strain SchuS4). A delay in onset of both antibiotic treatments allowed the rescue of all LVS-infected animals. However, for animals infected with SchuS4, only ciprofloxacin was efficacious and prolongation of treatment rescued all animals.

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Xiong, Huizhong, Rebecca A. Carter, Ingrid M. Leiner, Yi-Wei Tang, Liang Chen, Barry N. Kreiswirth y Eric G. Pamer. "Distinct Contributions of Neutrophils and CCR2+Monocytes to Pulmonary Clearance of Different Klebsiella pneumoniae Strains". Infection and Immunity 83, n.º 9 (8 de junio de 2015): 3418–27. http://dx.doi.org/10.1128/iai.00678-15.

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Klebsiella pneumoniaeis a common respiratory pathogen, with some strains having developed broad resistance to clinically available antibiotics. Humans can become infected with many differentK. pneumoniaestrains that vary in genetic background, antibiotic susceptibility, capsule composition, and mucoid phenotype. Genome comparisons have revealed differences betweenK. pneumoniaestrains, but the impact of genomic variability on immune-mediated clearance of pneumonia remains unclear. Experimental studies of pneumonia in mice have used the rodent-adapted 43816 strain ofK. pneumoniaeand demonstrated that neutrophils are essential for optimal host defense. It remains unclear, however, whether CCR2+monocytes contribute toK. pneumoniaeclearance from the lung. We selectively depleted neutrophils, CCR2+monocytes, or both from immunocompetent mice and determined susceptibility to infection by the 43816 strain and 4 newly isolated clinicalK. pneumoniaestrains. The clinicalK. pneumoniaestrains, including one carbapenem-resistant ST258 strain, are less virulent than 43816. Optimal clearance of each of the 5 strains required either neutrophils or CCR2+monocytes. Selective neutrophil depletion markedly worsened infection withK. pneumoniaestrain 43816 and three clinical isolates but did not increase susceptibility of mice to infection with the carbapenem-resistantK. pneumoniaeST258 strain. Depletion of CCR2+monocytes delayed recovery from infection with each of the 5K. pneumoniaestrains, revealing a contribution of these cells to bacterial clearance from the lung. Our findings demonstrate strain-dependent variation in the contributions of neutrophils and CCR2+monocytes to clearance ofK. pneumoniaepulmonary infection.

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Lunne, Tom, Toralv Berre, Knut H. Andersen, Stein Strandvik y Morten Sjursen. "Effects of sample disturbance and consolidation procedures on measured shear strength of soft marine Norwegian clays". Canadian Geotechnical Journal 43, n.º 7 (1 de julio de 2006): 726–50. http://dx.doi.org/10.1139/t06-040.

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After many decades of research, the issue of sample disturbance is still important as regards to determining reliable and representative soil parameters for foundation design in soft clays. Parallel laboratory tests have been carried out on high-quality block samples and ordinary piston tube samples from 12 deposits of soft Norwegian marine clays. Undrained triaxial and direct simple shear (DSS) tests on samples reconsolidated to the in situ effective stresses show that sample disturbance has a significant effect on the measured stress–strain–strength behaviour: the more disturbed the sample, the lower the shear stress at small strains and the higher the shear stress at large strains. Breakdown of the clay structure, including cementation bonds, is the assumed cause of lower shear resistance at small strains, whereas at large strains the shear resistance is governed mainly by the water content, which for soft clay samples, reconsolidated to the in situ effective stresses, will be lower, and the strength thereby higher, the more disturbed the sample. The work described herein also includes the effects of the consolidation procedure; in addition to the reconsolidation technique, both stress history and normalized soil engineering properties (SHANSEP) and delayed consolidation tests have been carried out.Key words: soft clays, sample disturbance, consolidation procedures, stress–strain–strength behaviour, stress–strain–time behaviour.

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44

Shen, Xixun, Congcong Zhang, Tao Zeng, Danhong Cheng y Jianshe Lian. "Understanding the microscopic deformation mechanism and macroscopic mechanical behavior of nanocrystalline Ni by the long-term stress relaxation test". International Journal of Modern Physics B 28, n.º 20 (19 de junio de 2014): 1450124. http://dx.doi.org/10.1142/s0217979214501240.

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The long-term stress relaxation tests with a relaxation time of about 7 h are performed on the bulk dense nanocrystalline Ni (with a mean grain size of 27 nm) pre-deformed at strain rate from 4.17 s-1- 4.17 × 10-6 s-1, where a phenomenon that the initial relaxation behavior of nc Ni depends on itself deformation history. That is, the nc Ni s pre-deformed at higher strain rate (not less than 4.17 × 10-3 s-1) exhibit a three-staged relaxation process from the initial near linear rapidly stress delayed (LRSD) stage and the subsequent lumber nonlinear stress delayed (LNSD) one and the final near linear slowly stress delayed (LSSD) one while only the later two stages are observed for the nc Ni s pre-deformed at low strain rate. The three-stage relaxation behavior is attributed to the transition from the initial dislocation-dominated plasticity to the mixture of dislocation motion and diffusion-based GB activity and finally to the entire diffusion-based GB activity including GB sliding or grain rotation in the rate-controlling deformation mechanism, which was illuminated by the attained three-staged strain rate sensitivity and activation volume and the exhaustion of mobile density of deformed nc Ni in the first two stages of relaxation. Such rate-controlling deformation mechanism well interpreted the macroscopic tensile mechanical behavior of nc Ni and simultaneously an optimizing strategy in improving the ductility of nc Ni is also mentioned.

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45

Dollé, Jean-Pierre, Barclay Morrison, Rene S. Schloss y Martin L. Yarmush. "Brain-on-a-chip microsystem for investigating traumatic brain injury: Axon diameter and mitochondrial membrane changes play a significant role in axonal response to strain injuries". TECHNOLOGY 02, n.º 02 (junio de 2014): 106–17. http://dx.doi.org/10.1142/s2339547814500095.

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Diffuse axonal injury (DAI) is a devastating consequence of traumatic brain injury, resulting in significant axon and neuronal degeneration. Currently, therapeutic options are limited. Using our brain-on-a-chip device, we evaluated axonal responses to DAI. We observed that axonal diameter plays a significant role in response to strain injury, which correlated to delayed elasticity and inversely correlated to axonal beading and axonal degeneration. When changes in mitochondrial membrane potential (MMP) were monitored an applied strain injury threshold was noted, below which delayed hyperpolarization was observed and above which immediate depolarization occurred. When the NHE-1 inhibitor EIPA was administered before injury, inhibition in both hyperpolarization and depolarization occurred along with axonal degeneration. Therefore, axonal diameter plays a significant role in strain injury and our brain-on-a-chip technology can be used both to understand the biochemical consequences of DAI and screen for potential therapeutic agents.

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46

Surendran, Naveen, Elizabeth Hiltbold, Nammalwar Sriranganathan, Bettina Heid, Stephen Boyle, Melissa Makris, Kurt Zimmerman y Sharon Witonsky. "The significance of TLRs in Brucella mediated dendritic cell activation in vitro and pulmonary clearance in vivo (42.16)". Journal of Immunology 184, n.º 1_Supplement (1 de abril de 2010): 42.16. http://dx.doi.org/10.4049/jimmunol.184.supp.42.16.

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Abstract Brucellosis is a worldwide zoonoses affecting 500,000 people annually with no approved human vaccines available. Live attenuated B. abortus vaccine strain RB51 protects cattle through CD4 and CD8 T-cell mediated responses. However, there are concerns regarding its efficacy and use as a live vaccine in people. Therefore, identifying how Brucella vaccines stimulate innate and adaptive immunity is critical to enhancing vaccine efficacy. Brucella stimulate dendritic cells (DCs) through Toll-Like Receptors (TLRs) 2, 4 and 9. In this study, to identify how rough vaccine strains stimulate DC activation and function in vitro, we used vaccine strain RB51 versus pathogenic strain 2308 to stimulate bone marrow derived dendritic cells (BMDCs) from TLR2, 4 or 9 knockout (KO) and wild type BALB/c mice. Since inhalation of infected aerosols is one of the most common routes of exposure, in vivo clearance of strain RB51 compared to strain 2308 from intranasally (IN) infected TLR KO vs. control BALB/c mice was assessed. We determined that strain RB51 induced significant (p≤0.05) DC activation compared to strain 2308 which was TLR independent. However, strain RB51 induced TNF - α production was TLR2 and TLR9 dependent and IL-12 production was TLR2 and TLR4 dependent. TLR4 KO mice had significantly (p≤0.05) delayed pulmonary clearance of strain RB51 in vivo at day 14 post infection. Based on these data, future studies will focus on enhancing the protective ability of strain RB51.

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47

Drake, S. R. y Tom Eisele. "143 COLOR AND QUALITY OF `DELICIOUS' APPLES BY DELAYED HARVEST DATE AND CONTROLLED-ATMOSPHERE STORAGE". HortScience 29, n.º 5 (mayo de 1994): 449b—449. http://dx.doi.org/10.21273/hortsci.29.5.449b.

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Red color of 2 strains (`Bisbee' and `Red Chief) of `Delicious' apples was increased (25%) by a 10 day delay beyond recommended harvest date. Color of `Oregon Spur' did not change during this 10 day period. Soluble solids content and size were also increased, but firmness decreased by 12%. In 2 of 3 years, firmness at harvest was 73 N or greater in all strains and these fruit lost little firmness during 9 months of CA. Poor firmness (<63 N) at harvest resulted in fruit with unacceptable firmness (53 N) after storage regardless of harvest time or strain. Loss in fruit quality was evident after a 5 day delay in atmosphere establishment with no further loss after a 10 day delay. `Oregon Spur' had the best color regardless of harvest, followed by `Bisbee' and `Red Chief. All strains (`Oregon Spur', `Bisbee' and `Red Chief) had good quality after long term CA. Sensory panelists could not distinguish flavor differences between strains, harvest dates or delay in storage establishment.

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48

Lee, Sooheyong, Wonhyuk Jo, Anthony D. DiChiara, Timothy P. Holmes, Stephen Santowski, Yong Chan Cho y Eric C. Landahl. "Probing Electronic Strain Generation by Separated Electron-Hole Pairs Using Time-Resolved X-ray Scattering". Applied Sciences 9, n.º 22 (8 de noviembre de 2019): 4788. http://dx.doi.org/10.3390/app9224788.

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Photogeneration of excess charge carriers in semiconductors produces electronic strain. Under transient conditions, electron-hole pairs may be separated across a potential barrier. Using time-resolved X-ray diffraction measurements across an intrinsic AlGaAs/n-doped GaAs interface, we find that the electronic strain is only produced by holes, and that electrons are not directly observable by strain measurements. The presence of photoinduced charge carriers in the n-doped GaAs is indirectly confirmed by delayed heat generation via recombination.

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49

Irkitova, Alena N., Angelina V. Malkova y Dina E. Dudnik. "A natural bacterial strain Bacillus pumilus 16: Identification and antibiotic resistance evaluation". Acta Biologica Sibirica 7 (6 de diciembre de 2021): 391–406. http://dx.doi.org/10.3897/abs.7.e78412.

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Microbial biopreparations are actively used to prevent, diagnose, and treat infectious, allergic, tumor, and autoimmune diseases in humans and animals; to stimulate the growth and development of plant crops. Natural bacterial strains with valuable technical properties are a vital biological resource for developing new biopreparations and rotating already known microbial preparations in the world market. This study describes a new natural strain B. pumilus 16, which was isolated from the rhizosphere of Cichorium. The strain was identified using morphological and physiological parameters, biochemical tests, and primers Pum-f. and Pum-r. Antibiotic sensitivity and antagonistic activity against Escherichia coli were determined by diffusion of discs and delayed antagonism methods, respectively. The new natural strain (like type strains) fermented arabinose, cellobiose, mannitol, mannose, salicin, sucrose, and trehalose, and gave a positive reaction to arginine dihydrolase, ONPG, Voges-Proskauer test. It also gave a negative reaction to inositol, raffinose, sorbitol, methyl-D-glucoside, inulin, and lecithinase. B. pumilus 16, unlike the test strains, was capable of fermenting citrate. Strain B. pumilus 16 was highly sensitive to cephalexin (37.9±0.7 mm) and enrofloxacin (25.7±8.9 mm); sensitive to ole-andomycin (17.1±1.9 mm), benzylpenicillin (18.5±1.2 mm), and monomycin (16.0±0.6 mm); resist-ant to oxacillin. By the agar blocks method (7.3±1.5 mm), a more pronounced antagonism of the new strain against E. coli was recorded than by the method of agar wells (5.3±0.6 mm). Due to the level of antagonistic activity, B. pumilus 16 was more effective than the type strains (two of which did not show an antagonistic effect). On the basis of this, the new strain can be recommended for inclusion in the bacterial preparation composition for the national economy.

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50

Berthelin, Bénédicte, Joseph Zucca y Jean-François Mescle. "Sélection et analyse de mutants thermotolérants de Zymomonas mobilis, producteurs d'éthanol". Canadian Journal of Microbiology 31, n.º 10 (1 de octubre de 1985): 934–37. http://dx.doi.org/10.1139/m85-175.

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Mutagenesis of Zymomonas mobilis ATCC 10988 induced by nitrosoguanidine and ethyl methanesulfonate leads to the acquisition of thermotolerant character. The nitrosoguanidine allows the obtention of the best mutants. At 38 °C, these mutant strains have growth kinetics and ethanol production rates similar to those of the wild-type strain grown at 30 °C. The mutants show delayed ethanol production when compared with Zymomonas mobilis ATCC 10988: this production occurs in part during the exponential growth phase and is still active at the beginning of the stationary phase.

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