•Appelmans protocol broadens host range of a phage cocktail targeting acinetobacter baumannii.•Prophage induction and recombination contributes to the broadening of the phage cocktail host ...range.•Recombination of prophages from encountered bacterial strains generates expanded host range phages.•Induced phages demonstrated limited stability, unsuitable for therapy.
Infections caused by carbapenem-resistant Acinetobacter baumannii (CRAB) present significant healthcare challenges due to limited treatment options. Bacteriophage (phage) therapy offers potential as an alternative treatment. However, the high host specificity of phages poses challenges for their therapeutic application. To broaden the phage spectrum, laboratory-based phage training using the Appelmans protocol was employed in this study. As a result, the protocol successfully expanded the host range of a phage cocktail targeting CRAB. Further analysis revealed that the expanded host range phages isolated from the output cocktail were identified as recombinant derivatives originating from prophages induced from encountered bacterial strains. These findings provide valuable genetic insights into the protocol's mechanism when applied to phages infecting A. baumannii strains that have never been investigated before. However, it is noteworthy that the expanded host range phages obtained from this protocol exhibited limited stability, raising concerns about their suitability for therapeutic purposes.
In this study, we aimed to design a novel and effective bacteriophage cocktail that can target both wild-type bacteria and phage-resistant mutants. To achieve this goal, we isolated four phages ...(U2874, phi_KPN_H2, phi_KPN_S3, and phi_KPN_HS3) that recognized different bacterial surface molecules using phage-resistant bacteria. We constructed three phage cocktails and tested their phage resistance-suppressing ability against multidrug-resistant Klebsiella pneumoniae. We argue that the phage cocktail that induces resensitization of phage susceptibility exhibited superior phage resistance-suppressing ability. Moreover, we observed trade-off effects that manifested progressively in phage-resistant bacteria. We hypothesize that such trade-off effects can augment therapeutic efficacy. We also recommend collating phage host range data against phage-resistant mutants in addition to wild-type bacteria when establishing phage banks to improve the efficiency of phage therapy. Our study underscores the importance of phage host range data in constructing effective phage cocktails for clinical use.
Recent advances in microalgae biotechnology have proven that these microorganisms contain a number of bioactive molecules, that can be used as food additives that help prevent disease. The green ...microalga Chlorella vulgaris presents several biomolecules, such as lutein and astaxanthin, with antioxidant capacity, which can play a protective role in tissues. In this study, we produced and analyzed a C. vulgaris functional alcoholic beverage (produced using a traditional Brazilian alcoholic beverage, cachaça, and C. vulgaris biomass). Assays were conducted in vitro by radical scavenging tests, and in vivo, by modeling cortical spreading depression in rat brains. Scavenging radical assays showed that consumption of the C. vulgaris alcoholic beverage had a DPPH inhibition of 77.2%. This functional alcoholic beverage at a concentration of 12.5 g L-1 significantly improved cortical spreading depression velocity in the rat brains (2.89 mm min-1), when compared with cachaça alone (3.68 mm min-1) and control (distilled water; 3.25 mm min-1). Moreover, animals that consumed the functional beverage gained less weight than those that consumed just alcohol and the control groups. These findings suggest that the C. vulgaris functional alcoholic beverage plays a protective physiologic role in protecting brain cells from the effects of drinking ethanol.
As a consequence of worldwide improvement in health care, the aging portion of the human population has increased, now representing a higher proportion of the total population. This fact raises great ...concern regarding how to age while maintaining good brain function. Very often, alterations in brain electrophysiological signaling are associated with age-dependent functional disorders of the brain. Therefore, animal models suitable for the study of age-related changes in electrical activity of the brain can be very useful. Herein, we review changes in brain electrophysiological features as a function of age by analyzing studies in the rat brain on the phenomenon known as cortical spreading depression (CSD). Alterations in the brain's capability to generate and propagate CSD may be related to differences in the propensity to develop certain neurological diseases, such as epilepsy, stroke, and migraine, which can biunivocally interact with the aging process. In this review, we revisit ours and others' previous studies on electrophysiological features of the CSD phenomenon, such as its velocity of propagation and amplitude and duration of its slow negative DC shift, as a function of the animal age, as well as the interaction between age and other factors, such as ethanol consumption, physical exercise, and nutritional status. In addition, we discuss one relatively new feature through which CSD modulates brain signaling: the ability to potentiate the brain's spontaneous electrical activity. We conclude that the CSD model might importantly contribute to a better understanding of the aging/brain signaling relationship.
This study explores the multifaceted influence of litter size, maternal care, exercise, and aging on rats' neurobehavioral plasticity and dentate gyrus microglia dynamics. Body weight evolution ...revealed a progressive increase until maturity, followed by a decline during aging, with larger litters exhibiting lower weights initially. Notably, exercised rats from smaller litters displayed higher body weights during the mature and aged stages. The dentate gyrus volumes showed no significant differences among groups, except for aged sedentary rats from smaller litters, which exhibited a reduction. Maternal care varied significantly based on litter size, with large litter dams showing lower frequencies of caregiving behaviors. Behavioral assays highlighted the detrimental impact of a sedentary lifestyle and reduced maternal care/large litters on spatial memory, mitigated by exercise in aged rats from smaller litters. The microglial dynamics in the layers of dentate gyrus revealed age-related changes modulated by litter size and exercise. Exercise interventions mitigated microgliosis associated with aging, particularly in aged rats. These findings underscore the complex interplay between early-life experiences, exercise, microglial dynamics, and neurobehavioral outcomes during aging.
Early growth response-1 (Egr-1), a zinc finger transcription factor, is an upstream master switch of the inflammatory response, and its expression can be used to investigate the spatial and temporal ...extent of inflammatory changes in the brain. Cortical spreading depression (CSD) is a slowly propagating (2–5 mm/min) wave of depolarization of neurons and astrocytes in humans that contributes to migraines and possibly to other brain pathologies. In rodents, CSD can be induced experimentally, which involves unilateral depolarization that is associated with microglial and astrocyte activation. The impact of CSD on structures beyond the affected hemisphere has not been explored. Here, we used unbiased stereological methods to investigate potential correlations between the number of CSD episodes and Egr-1 expression in the ipsilateral and contralateral hemispheres. CSD was elicited by the focal application of a 2% KCl solution over the left premotor cortex. Electrophysiological events were recorded using a pair of Ag/AgCl agar-Ringer electrodes for 2 or 6 hours. An optical fractionator was used to count the Egr-1 positive cells. We found that CSD increased Egr-1 expression in a time- and event-dependent manner in the ipsilateral/left hemisphere. Although CSD did not cross the midline, multiple CSD inductions were associated with an increased number of Egr -1 positive cells in the contralateral/right hemisphere. Thus, repeated CSD waves may have far reaching effects that are more global than previously considered possible. The mechanism of contralateral activation is unknown, but we speculate that callosal projections from the depolarized hemisphere may be responsible.
Background
We previously demonstrated that acute and chronic treatment with ethanol (EtOH), respectively, decelerated and accelerated the propagation of cortical spreading depression (CSD) in rats ...and that the antioxidant carotenoid astaxanthin counteracted these effects. Here, we investigated whether noncarotenoid antioxidants exert the same action by testing α‐tocopherol in rats of various ages, with and without 5 to 10 days of EtOH abstinence.
Methods
Male Wistar young adult (60 to 80 days old) and mature adult (150 to 180 days old) rats received per gavage acute (1 day) or chronic (21 days) treatment with 3 g/kg/d EtOH combined with acute (300 mg/kg) or chronic (85 mg/kg/d) treatment with α‐tocopherol or vehicle‐only treatment (olive oil and water for α‐tocopherol and EtOH, respectively). CSD was recorded over 4 hours and the velocity of CSD propagation was calculated. On both ages, animals under chronic EtOH treatment were subjected to CSD recording immediately after EtOH treatment or after a 5‐ to 10‐day period of EtOH abstinence.
Results
In both age groups, acute and chronic EtOH exposure decelerated and accelerated CSD, respectively, versus the corresponding control groups. Addition of α‐tocopherol counteracted the effects of EtOH on CSD, returning CSD velocities to levels in control groups (p < 0.05). Chronic α‐tocopherol (85 mg/kg/d) did not alter CSD.
Conclusions
Our data reinforce the counteracting role of antioxidants on brain processes involved in the action of EtOH on CSD and suggest that this role is not a particular property of carotenoids; furthermore, this general feature of antioxidants is not substantially influenced by age or by 5 to 10 days of EtOH abstinence.
Recordings of direct current potential change of cortical spreading depression (CSD) in five young adult and five mature adult rats representative of the following groups: naïve (no treatment), tocopherol, acute ethanol, chronic ethanol, and ethanol + tocopherol. Vertical dashed lines indicate the latency for a CSD wave to cross the interelectrode distance. Acute and chronic treatment with ethanol, respectively, shortened and increased latencies versus control conditions. Tocopherol treatment counteracted this effect of ethanol.
Background
Ethanol (EtOH) abuse and insufficient ingestion of antioxidants are external factors that can alter brain electrophysiology. Our previous studies have demonstrated that the ...excitability‐related brain electrophysiological phenomenon known as cortical spreading depression (CSD) was facilitated by chronic EtOH intake, and chronic treatment with carotenoids attenuated this effect. Here, we investigated the acute effect of a single EtOH administration on CSD in young and adult rats previously (1 hour) treated with 10 μg/kg of astaxanthin.
Methods
Male Wistar rats (5 young‐ and 5 adult groups, 60 to 80 and 150 to 180 days of age, respectively) were treated by 2 gavage procedures at 1‐hour interval as follows: groups 1 and 2 received astaxanthin in gavage I combined with EtOH (group 1) or water (group 2) in gavage II; groups 3 and 4 received olive oil (the vehicle in which astaxanthin was dissolved) in gavage I combined with EtOH (group 3) or water (group 4) in gavage II; group 5 received water in gavage I combined with EtOH in gavage II. CSD was recorded on the cortical surface for 4 hours.
Results
Compared to the respective water and oil controls (groups 2 and 4; CSD velocities: 3.73 ± 0.09 and 3.78 ± 0.07 mm/min in the young groups; 2.99 ± 0.10 and 3.05 ± 0.19 mm/min in the adult groups), a single dose of EtOH (groups 3 and 5) decreased CSD propagation velocities (3.29 ± 0.23 and 3.16 ± 0.10 mm/min in the young groups; 2.71 ± 0.27 and 2.75 ± 0.31 mm/min in the adult groups). Astaxanthin antagonized the impairing effect of acute EtOH on CSD (group 1; mean velocity: 3.70 ± 0.19 and 3.13 ± 0.16 mm/min for the young and adult groups, respectively).
Conclusions
The results showed an antagonistic effect of acute EtOH treatment on CSD propagation that was reverted by astaxanthin. The EtOH–astaxanthin interaction was not influenced by the age, as it was found in both young and adult animals.
Background: The consumption of alcoholic drinks is a frequent drug‐abuse situation, which is associated to a wide variety of pathological disturbances affecting several organs, including the brain. ...We have previously shown in the developing rat brain that ethanol intake facilitates the propagation of cortical spreading depression (CSD), an excitability‐related neural phenomenon present in several animal species. This electrophysiological effect was attenuated by a shrimp (Litopenaeus vannamei) carotenoids extract. Here we investigated the effects of pure astaxanthin, the main carotenoid found in shrimp, on CSD.
Methods: Adult Wistar rats were treated per gavage, during 18 days, with 2.5, 10 or 90 μg/kg/d astaxanthin dissolved in ethanol (3 g/kg) and CSD was recorded on the cortical surface 1 to 3 days thereafter. Four groups, treated respectively with ethanol, distilled water and soybean oil with‐ and without astaxanthin were also studied for comparison with the ethanol + astaxanthin groups.
Results: Ethanol‐treated rats displayed higher CSD‐velocities (mean values, in mm/min, per hour of recording ranging from 4.08 ± 0.09 to 4.12 ± 0.16), compared to the distilled water‐group (from 3.19 ± 0.13 to 3.27 ± 0.06). Addition of astaxanthin to ethanol lead to lower CSD‐velocities in a dose‐dependent manner, ranging from 3.68 ± 0.09 to 3.97 ± 0.22 for the 2.5 μg/kg/d‐dose, from 3.29 ± 0.09 to 3.32 ± 0.07 for the 10 μg/kg/d‐dose, and from 2.89 ± 0.13 to 2.92 ± 0.11 for the 90 μg/kg/d‐dose. The velocities of the soybean oil groups (with and without astaxanthin) were not statistically different from the 10 μg/kg/d astaxanthin + ethanol and distilled water groups.
Conclusion: The results demonstrate the antagonistic effect of astaxanthin against the ethanol‐induced facilitation of CSD propagation. Probably carotenoid antioxidant properties are involved in such effects.
Here we report the first incidence of New Delhi metallo-β-lactamase (NDM-1)-producing
in Peru, identified via a strain-based nosocomial surveillance project carried out in Lima and Iquitos. The
gene ...was detected by multiplex polymerase chain reaction (PCR) and confirmed by loci sequencing.
is a nearly ubiquitous and promiscuous nosocomial pathogen, and the acquisition of
by
may facilitate an increase in the prevalence of this important resistance marker in other nosocomial pathogens.
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