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This study demonstrates that novel polymer production can be achieved by introducing pTAM, a broad-host-range plasmid expressing codon-optimized genes encoding Clostridium propionicum propionate CoA transferase (PctCp, Pct532) and a modified Pseudomonas sp. MBEL 6-19 polyhydroxyalkanoate (PHA) synthase 1 (PhaC1Ps6-19, PhaC1400), into phaC mutant strains of the native polymer producers Sinorhizobium meliloti and Pseudomonas putida. Both phenotypic analysis and gas chromatography analysis indicated the synthesis and accumulation of biopolymers in S. meliloti and P. putida strains. Expression in S. meliloti resulted in the production of PLA homopolymer up to 3.2% dried cell weight (DCW). The quaterpolymer P (3HB-co-LA-co-3HHx-co-3HO) was produced by expression in P. putida. The P. putida phaC mutant strain produced this type of polymer the most efficiently with polymer content of 42% DCW when cultured in defined media with the addition of sodium octanoate. This is the first report, to our knowledge, of the production of a range of different biopolymers using the same plasmid-based system in different backgrounds. In addition, it is the first time that the novel polymer (P(3HB-co-LA-co-3HHx-co-3HO)), has been reported being produced in bacteria.

Background There are complex interactions between aging, frailty, diet, and the gut microbiota; modulation of the gut microbiota by diet could lead to healthier aging. The purpose of this study was to test the effect of diets differing in sugar, fat, and fiber content upon the gut microbiota of mice humanized with microbiota from healthy or frail older people. We also performed a 6-month dietary fiber supplementation in three human cohorts representing three distinct life-stages. Methods Mice were colonized with human microbiota and then underwent an 8-week dietary intervention with either a high-fiber/low-fat diet typical of elderly community dwellers or a low-fiber/high-fat diet typical of long-stay residential care subjects. A cross-over design was used where the diets were switched after 4 weeks to the other diet type to identify responsive taxa and innate immunity changes. In the human intervention, the subjects supplemented their normal diet with a mix of five prebiotics (wheat dextrin, resistant starch, polydextrose, soluble corn fiber, and galactooligo-saccharide) at 10 g/day combined total, for healthy subjects and 20 g/day for frail subjects, or placebo (10 g/day maltodextrin) for 26 weeks. The gut microbiota was profiled and immune responses were assayed by T cell markers in mice, and serum cytokines in humans. Results Humanized mice maintained gut microbiota types reflecting the respective healthy or frail human donor. Changes in abundance of specific taxa occurred with the diet switch. In mice with the community type microbiota, the observed differences reflected compositions previously associated with higher frailty. The dominance of Prevotella present initially in community inoculated mice was replaced by Bacteroides , Alistipes , and Oscillibacter . Frail type microbiota showed a differential effect on innate immune markers in both conventional and germ-free mice, but a moderate number of taxonomic changes occurring upon diet switch with an increase in abundance of Parabacteroides , Blautia , Clostridium cluster IV, and Phascolarctobacterium . In the human intervention, prebiotic supplementation did not drive any global changes in alpha- or beta-diversity, but the abundance of certain bacterial taxa, particularly Ruminococcaceae ( Clostridium cluster IV), Parabacteroides , Phascolarctobacterium , increased, and levels of the chemokine CXCL11 were significantly lower in the frail elderly group, but increased during the wash-out period. Conclusions Switching to a nutritionally poorer diet has a profound effect on the microbiota in mouse models, with changes in the gut microbiota from healthy donors reflecting previously observed differences between elderly frail and non-frail individuals. However, the frailty-associated gut microbiota did not reciprocally switch to a younger healthy-subject like state, and supplementation with prebiotics was associated with fewer detected effects in humans than diet adjustment in animal models.

Bacteria threaten human and animal health, and standard antibiotics no longer effective. Antibiotic-resistant microorganisms can make infection treatment challenging and perhaps fail. Investigating the attributes of cyclotide, a peptide with promising antibacterial properties that holds great potential in the field of antibiotic research. The structure of these cyclic peptides involves six conserved cysteine residues that form three disulfide bonds, resulting in a cyclic cystine knot (CCK). This feature guarantees their durability when exposed to changes in temperature, chemicals, and enzymatic degradation. The two cyclotides, cycloviolacin O17 and mra30, were obtained from Viola dalatensis Gadnep through a series of techniques including the use of a 50% acetonitrile/49% miliQ water/1% formic acid solution for extraction, ammonium salt precipitation, RP-HPLC purification and sequence identification by LC-MS/MS. These cyclotides exhibit antibacterial effects on specific strains of bacteria like Staphylococcus aureus, Bacillus subtilis, and Pseudomonas aeruginosa at a concentration of 0.2 mg/mL, leading to inhibition zones ranging from 10 to 14 mm. In addition, the disulfide bonds play a crucial role in the antibacterial function of cyclotides. Disrupting the disulfide bonds through ankylation reaction results in the loss of antibacterial properties in the cyclotides (cyO17 and mra30). The minimum inhibitory concentration (MIC) values of mra30 and cyO17 are significantly low, ranging from 0.1 to 0.6 µM. These values are approximately three times lower than the MIC values observed in salt precipitation samples.

Alpha oscillations (7–14Hz) are modulated in response to visual temporal and spatial cues. However, the neural response to alerting cues is less explored, as is how this response is affected by healthy aging. Using scalp EEG, we examined how visual cortical alpha activity relates to working memory performance. Younger (20–30 years) and older (60–70 years) participants were presented with a visual alerting cue uninformative of the position or size of a lateralized working memory array. Older adults showed longer response times overall and reduced accuracy when memory load was high. Older adults had less consistent cue-evoked alpha phase resetting than younger adults, which predicted worse performance. Alpha phase prior to memory array presentation predicted response time, but the relationship between phase and response time was weaker in older adults. These results suggest that changes in alpha phase dynamics, especially prior to presentation of task-relevant stimuli, potentially contribute to age-related cognitive decline. •Older adults had worse accuracy and longer response times on a working memory task.•Older adults had less consistent alpha phase response to a pretarget alerting cue.•Consistency of phase response to the alerting cue predicted accuracy.•Pretarget alpha phase predicted response times on a trial-by-trial basis.•The relationship between alpha phase and response time was weaker in older adults.

Background/Objectives: Campylobacteriosis in human populations is an ongoing issue in both developed and developing countries. Poultry production is recognized as a reservoir for antimicrobial resistance and main source of human Campylobacter infection. Methods: In this study, sixty-five Campylobacter isolates were cultured from fecal samples collected from 17 flocks of broiler chickens in Alberta, Canada over two years (2015–2016). Susceptibility assays and PCR assays were performed to characterize resistance phenotypes and resistance genes. Conjugation assays were used to examine the mobility of AMR phenotypes. Results: Campylobacter jejuni was the predominant species recovered during both years of sampling. There were no Campylobacter coli isolates found in 2015; however, approximately 33% (8/24) of isolates collected in 2016 were Campylobacter coli. The two most frequent antimicrobial resistance patterns in C. jejuni collected in 2015 were tetracycline (39%) and azithromycin/clindamycin/erythromycin/telithromycin resistance (29%). One isolate collected in 2015 has resistance pattern ciprofloxacin/nalidixic acid/tetracycline. The tetO gene was detected in all tetracycline resistant isolates from 2015. The cmeB gene was detected in all species isolates with resistance to azithromycin/clindamycin/erythromycin/telithromycin, and from two isolates with tetracycline resistance. Alignment of the nucleotide sequences of the cmeB gene from C. jejuni isolates with different resistance patterns revealed several single nucleotide polymorphisms. A variety of multi-drug resistance patterns were observed through conjugation experiments. Conclusions: These data suggest that poultry production may serve as a potential reservoir for and source of transmission of multi-drug resistant Campylobacter jejuni and supports the need for continued surveillance.

Background Coronavirus disease 2019 (COVID-19) pandemic constituted the largest global health crisis in recent generations. It may also have disrupted the pattern of antimicrobial use (AMU) and subsequently affected the development of antimicrobial resistance (AMR) – a grave human health concern. This study aimed to give an overview of existing AMR surveillance systems and evaluate the impact of COVID-19 on AMU and AMR in the Nordics using data from these systems. Methods Nordic AMU data (2017–2022) were extracted from national annual reports (for both humans and animals) and the European Surveillance System (TESSy) (for humans only). For humans, AMU was expressed in defined daily dose (DDD) per 1000 inhabitants per day; for animals, it was expressed in kilogram (kg). Nordic human AMR data (2017–2022) were extracted from TESSy. Multilevel linear regression and negative binomial regression models were used to fit the TESSy data. Data between 2017 and 2019 were categorised as the pre-COVID-19 time, while data between 2020 and 2022 were the per-COVID-19 time. Results Denmark had a remarkably greater AMU in animals (about 10 times greater) than Norway, Sweden, and Finland. Iceland had the highest human AMU, while Sweden had the lowest. Drug categories, countries, and sectors were significant predictors in the model used to fit human AMU. Bacterial species and drug categories were significant predictors in the models used to fit human resistant Gram-negative and Gram-positive bacteria. The COVID-19 time was not a significant predictor in these models. Among the Nordics, Iceland had the lowest number of resistant isolates; however, high human AMU remains a great concern for Iceland. Conclusions The study provided insight into current existing AMR surveillance systems in the Nordics. It also showed that the COVID-19 pandemic had very little impact on AMU and AMR in theses countries. This implied that strict regulations on AMU as well as well-coordinated national AMR surveillance systems in the Nordics mitigated the development of AMR crisis also during COVID-19 pandemic. However, the Nordics would still benefit further from a standardized AMR surveillance at regional level, which ultimately facilitate timely information sharing and improve our preparedness for and response to future pandemics and/or large-scale outbreaks.

While transgenerational plasticity may buffer ectotherms to warming and pesticides separately, it remains unknown how combined exposure to warming and pesticides in the parental generation shapes the vulnerability to these stressors in the offspring. We studied the transgenerational effects of single and combined exposure to warming (4°C increase) and the pesticide chlorpyrifos on life‐history traits of the vector mosquito Culex pipiens. Parental exposure to a single stressor, either warming or the pesticide, had negative effects on the offspring: parental exposure to both warming and the pesticide resulted in an overall lower offspring survival, and a delayed offspring metamorphosis. Parental exposure to a single stressor did, however, not alter the vulnerability of the offspring to the same stressor in terms of survival. Parental pesticide exposure resulted in larger offspring when the offspring experienced the same stressor as the parents. Within both the parental and offspring generations, warming made the pesticide more toxic in terms of survival. Yet, this synergism disappeared in the offspring of parents exposed to both stressors simultaneously because in this condition, the pesticide was already more lethal at the lower temperature. Our results indicate that transgenerational effects will not increase the ability of this vector species to deal with pesticides in a warming world. Bifactorial transgenerational experiments are crucial to understand the combined impact of warming and pesticides across generations, hence to assess the efficacy of vector control in a warming world.

Blueberry (BB) consumption is linked to improved health. The bioconversion of the polyphenolic content of BB by fermentative bacteria in the large intestine may be a necessary step for the health benefits attributed to BB consumption. The identification of specific gut microbiota taxa that respond to BB consumption and that mediate the bioconversion of consumed polyphenolic compounds into bioactive forms is required to improve our understanding of how polyphenols impact human health. We tested the ability of polyphenol-rich fractions purified from whole BB—namely, anthocyanins/flavonol glycosides (ANTH/FLAV), proanthocyanidins (PACs), the sugar/acid fraction (S/A), and total polyphenols (TPP)—to modulate the fecal microbiota composition of healthy adults in an in vitro colon system. In a parallel pilot study, we tested the effect of consuming 38 g of freeze-dried BB powder per day for 6 weeks on the fecal microbiota of 17 women in two age groups (i.e., young and older). The BB ingredients had a distinct effect on the fecal microbiota composition in the artificial colon model. The ANTH/FLAV and PAC fractions were more effective in promoting microbiome alpha diversity compared to S/A and TPP, and these effects were attributed to differentially responsive taxa. Dietary enrichment with BB resulted in a moderate increase in the diversity of the microbiota of the older subjects but not in younger subjects, and certain health-relevant taxa were significantly associated with BB consumption. Alterations in the abundance of some gut bacteria correlated not only with BB consumption but also with increased antioxidant activity in blood. Collectively, these pilot data support the notion that BB consumption is associated with gut microbiota changes and health benefits.

While poly(3-hydroxybutyrate- co -3-hydroxyvalerate) [P(3HB- co -3HV)] is a biodegradable commodity plastic with broad applications, its microbial synthesis is hindered by high production costs primarily associated with the supplementation of related carbon substrates (e.g. propionate or valerate). Here we report construction of engineered Escherichia coli strains for direct synthesis of P(3HB- co -3HV) from an unrelated carbon source (e.g. glucose or glycerol). First, an E. coli strain with an activated sleeping beauty mutase (Sbm) operon was used to generate propionyl-CoA as a precursor. Next, two acetyl-CoA moieties or acetyl-CoA and propionyl-CoA were condensed to form acetoacetyl-CoA and 3-ketovaleryl-CoA, respectively, by functional expression of β-ketothiolases from Cupriavidus necator (i.e. PhaA and BktB). The resulting thioester intermediates were channeled into the polyhydroxyalkanoate (PHA) biosynthetic pathway through functional expression of acetoacetyl-CoA reductase (PhaB) for thioester reduction and PHA synthase (PhaC) for subsequent polymerization. Metabolic engineering of E. coli host strains was further conducted to enhance total PHA content and the 3-hydroxyvaleryl (3HV) monomer fraction in the copolymer. Using a selection of engineered E. coli strains for batch cultivation with an unrelated carbon source, we achieved high-level P(3HB- co -3HV) production with the 3HV monomer fraction ranging from 3 to 19 mol%, demonstrating the potential industrial applicability of these whole-cell biocatalysts.

In shrimp aquaculture systems, zooplankton represent a potential food source for larvae and juveniles due to its high nutritional value and size-suitability. Although many studies investigated zooplankton community in various aquaculture systems, little knowledge exists on how this varies among different culture systems. Here, we investigated how zooplankton abundance, diversity and density differ among three shrimp culture systems, namely extensive, semi-intensive and intensive. In total, 28 zooplankton species of 7 different groups were recorded. Copepods, rotifers and decapods were dominant groups, accounting for more than 80% of total zooplankton density. Brachionus plicatilis was the most abundant species. A key finding was that species richness and diversity were higher in extensive and semi-intensive cultures than in intensive culture. Zooplankton density was highest (106 ind m-3) in extensive systems which was 3 and 8 times higher than in intensive and semi-intensive systems, respectively. Density of zooplankton was lowest (4886 ind/m3 in May) in the early stage of culture but notably higher in the later stage (8.9 × 105 ind m-3 in June and 5.9 × 105 ind m-3 in July). This is probably because the zooplankton community in the culture systems experienced a high predation pressure by cultured organisms during the early stage but were gradually less preyed upon over time. The obtained findings suggest that zooplankton assemblages in the ponds appeared to be an important food source for cultured organisms, especially during the early stage. It would be beneficial to establish an abundant assemblage of zooplankton in shrimp culture system prior to stocking.