Existence of log-phase Escherichia coli persisters and lasting memory of a starvation pulse

The vast majority of a bacterial population is killed when treated with a lethal concentration of antibiotics. The time scale of this killing is often comparable with the bacterial generation time before the addition of antibiotics. Yet, a small subpopulation typically survives for an extended period. However, the long-term killing dynamics of bacterial cells has not been fully quantified even in well-controlled laboratory conditions. We constructed a week-long killing assay and followed the survival fraction of Escherichia coli K12 exposed to a high concentration of ciprofloxacin. We found that long-term survivors were formed during exponential growth, with some cells surviving at least 7 d. The long-term dynamics contained at least three time scales, which greatly enhances predictions of the population survival time compared with the biphasic extrapolation from the short-term behavior. Furthermore, we observed a long memory effect of a brief starvation pulse, which was dependent on the (p)ppGpp synthase relA. Specifically, 1 h of carbon starvation before antibiotics exposure increased the surviving fraction by nearly 100-fold even after 4 d of ciprofloxacin treatment.

Epidemiology of Nosema spp. and the effect of indoor and outdoor wintering on honey bee colony population and survival in the Canadian Prairies

The epidemiology of Nosema spp. in honey bees, Apis mellifera, may be affected by winter conditions as cold temperatures and differing wintering methods (indoor and outdoor) provide varying levels of temperature stress and defecation flight opportunities. Across the Canadian Prairies, including Alberta, the length and severity of winter vary among geographic locations. This study investigates the seasonal pattern of Nosema abundance in two Alberta locations using indoor and outdoor wintering methods and its impact on bee population, survival, and commercial viability. This study found that N. ceranae had a distinct seasonal pattern in Alberta, with high spore abundance in spring, declining to low levels in the summer and fall. The results showed that fall Nosema monitoring might not be the best indicator of treatment needs or future colony health outcomes. There was no clear pattern for differences in N. ceranae abundance by location or wintering method. However, wintering method affected survival with colonies wintered indoors having lower mortality and more rapid spring population build-up than outdoor-wintered colonies. The results suggest that the existing Nosema threshold should be reinvestigated with wintering method in mind to provide more favorable outcomes for beekeepers. Average Nosema abundance in the spring was a significant predictor of end-of-study winter colony mortality, highlighting the importance of spring Nosema monitoring and treatments.

1.36 million years of Mediterranean forest refugium dynamics in response to glacial–interglacial cycle strength

The sediment record from Lake Ohrid (Southwestern Balkans) represents the longest continuous lake archive in Europe, extending back to 1.36 Ma. We reconstruct the vegetation history based on pollen analysis of the DEEP core to reveal changes in vegetation cover and forest diversity during glacial–interglacial (G–IG) cycles and early basin development. The earliest lake phase saw a significantly different composition rich in relict tree taxa and few herbs. Subsequent establishment of a permanent steppic herb association around 1.2 Ma implies a threshold response to changes in moisture availability and temperature and gradual adjustment of the basin morphology. A change in the character of G–IG cycles during the Early–Middle Pleistocene Transition is reflected in the record by reorganization of the vegetation from obliquity- to eccentricity-paced cycles. Based on a quantitative analysis of tree taxa richness, the first large-scale decline in tree diversity occurred around 0.94 Ma. Subsequent variations in tree richness were largely driven by the amplitude and duration of G–IG cycles. Significant tree richness declines occurred in periods with abundant dry herb associations, pointing to aridity affecting tree population survival. Assessment of long-term legacy effects between global climate and regional vegetation change reveals a significant influence of cool interglacial conditions on subsequent glacial vegetation composition and diversity. This effect is contrary to observations at high latitudes, where glacial intensity is known to control subsequent interglacial vegetation, and the evidence demonstrates that the Lake Ohrid catchment functioned as a refugium for both thermophilous and temperate tree species.

Factors affecting the crop damage by wild boar (Sus scrofa) and effects of population control in the Ticino and Lake Maggiore Park (North-western Italy)

Wild boar foraging impacts the crops, pastures, and meadows causing remarkable losses to agricultural income. Protected areas located in plains, such as the Ticino Valley Natural Park, are characterized by the coexistence of important natural habitats and intensive agricultural areas. In the Park, from 2010 to 2017, 49% of the complaints report an event of damage to maize and 43% to meadows. The total expense for reimbursements of the maize amounted to € 439,341.52, with damages concentrated in May, after sowing period and between August and September, during the milky stage of maize. For meadows reimbursements amounted to € 324,768.66, with damage events concentrated in February and March. To reduce damage to crops, the Park administration carried out lethal control of the wild boar population. From 2006 to 2017, the most used control method was culling from hunting hides. In our analysis, we did not find significant relationships between the number of shot boars and the damage amount. The factors that determine the decrease of damage probability to crops are mainly related to human disturbance and the characteristics of the fields. The predictive model of damage risk built comparing damaged and undamaged fields showed a good predictive ability. The population viability analyses showed that it is impossible to obtain a drastic reduction of population with the current harvest rate. By tripling it and focusing on the females and sub-adult a numerical reduction of 50% of the population would be achievable in 7 years and the probability of population survival would be halved in 3 years.

Genetic diversity in westernmost European populations of Halimione verrucifera (M. Bieb.) Aellen

Halimione verrucifera – an extreme halophyte plant species spread mainly in Asia with a few locations in South Eastern Europe – have the westernmost marginal populations in Romania. In order to asses population fitness and conservation status, genetic diversity among and within population was estimated using ISSR markers.A set of 6 primers were utilized after selection from a primer set which showed clear and reproducible banding patterns, generating a total number of 86 loci. A presence/absence matrix was generated by evaluating the gel electrophoresis banding patterns of PCR products. From this, genetic distances between individuals and populations were calculated, which were used in all subsequent generation of genetic diversity indices, assuming the Hardy-Weinberg equilibrium. Result revealed a low expected heterozygosity for both populations. Further testing by constructing an UPGMA dendrogram and a PCoA analysis confirmed that populations are clearly separated and with levels of genetic diversity that could ensure population survival in time and space.

Influence of Fara-darmani Consciousness Field on Bacterial Population Growth

The treatment of bacterial infections and the rising challenges of antibiotics resistance are global concerns and the primary topics in basic science and clinical microbiology. In the present study, the effectiveness of treatment of selected populations of bacteria using an immaterial and non-energetic method called Fara-darmani Consciousness Field treatment is investigated. Population growth was assessed by turbidimetry, colony counting and tetrazolium chloride reduction assays in non-treated control and Fara-darmani-treated groups. Our results suggest effectiveness of the Fara-darmani Consciousness Field on reducing various types of bacterial strain growth rates (up to 46%). In addition, along with a decrease in bacterial population, evidence of increased survival can be seen in the larger healthy population (up to about 60%). Thus, in this study, we confirm the effects of the Consciousness Field on bacterial population survival. This study also warrants additional research.

Validation of an exercise booklet for children with acute lymphoblastic leukemia

Introduction: Leukemia is the most common childhood cancer, and acute lymphoblastic leukemia (ALL) accounts for 75 to 80% of all such cases in this population. Survival has increased among children and adolescents due to advances in diagnosis and treatment, with a growing emphasis on the need for rehabilitation to improve functionality and quality of life, mitigating the long-term effects of treatment. Objective: To describe the process of compiling and validating an exercise booklet for children and adolescents during and after treatment for acute lymphoblastic leukemia. Methods: Methodological study using the Delphi technique for validation. The panel of experts consisted of seven healthcare professionals and three mothers of children without ALL. The booklet was evaluated using a form containing 15 items scored on a 5-point Likert scale, and by qualitative assessment. The frequency of the expert ratings, percentage agreement and content validity index (CVI) were presented for each item and the instrument as a whole. Analyses were performed in R 3.5.1 software. Results: The booklet containing stretching, aerobics, strength and relaxation exercises was validated in the second round, reaching 100% consensus. When assessed only by the mothers, 93.33% consensus was achieved in a single round. Conclusion: The exercises booklet was validated for use in the population studied.