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Abstract: In honeys, several molecules have been known for their antibacterial or wound healing properties. Corsican honeys just began to be tested for their antimicrobial activity with promising results on Pseudomonas aeruginosa. So, identification of active molecules and their mode of action was determined. Hydrogen peroxide concentrations were evaluated and, in parallel, the minimal inhibitory concentrations (MIC) values were performed with and without catalase. More, the quantity of phenolic compounds and ORAC assay were measured. Observation of antibacterial action was done using scanning electron microscopy (SEM) followed by plasmidic DNA extraction. MIC values of chestnut grove and honeydew maquis honeys vary between 7 and 8%, showing a strong antimicrobial capacity, associated with a plasmidic DNA degradation. When catalase is added, MIC values significatively increase (25%) without damaging DNA, proving the importance of H2O2. This hypothesis is confirmed by SEM micrographies which did not show any morphological damages but a depletion in bacterial population. Although, such low concentrations of H2O2 (between 23 μmol l−1 and 54 μmol l−1) cannot explain antimicrobial activity and might be correlated with phenolic compounds concentration. Thus, Corsican honeys seem to induce DNA damage when H2O2 and phenolic compounds act in synergy by a putative pro‐oxidant effect. Significance and Impact of the Study:: We started to determine the antibacterial efficiency of Corsican chestnut grove and honeydew maquis honeys on Pseudomonas aeruginosa. No morphological alteration of the bacterial surface was observed. Antimicrobial action seems to be related to the synergy between hydrogen peroxide and phenolic compounds. The exerted pro‐oxidant activity leads to a degradation of P. aeruginosa plasmidic DNA. This is the first study that investigate the primary antibacterial mechanism of Corsican honeys. [ABSTRACT FROM AUTHOR]

Background and Aims Ribonucleotide reductase (RNR), functioning in the de novo synthesis of deoxyribonucleoside triphosphates (dNTPs), is crucial for DNA replication and cell cycle progression. In most plants, the large subunits of RNR have more than one homologous gene. However, the different functions of these homologous genes in plant development remain unknown. In this study, we obtained the mutants of two large subunits of RNR in tomato and studied their functions. Methods The mutant ylc1 was obtained by ethyl methyl sulfonate (EMS) treatment. Through map-based cloning, complementation and knock-out experiments, it was confirmed that YLC1 encodes a large subunit of RNR (SlRNRL1). The expression level of the genes related to cell cycle progression, chloroplast biogenesis and photosynthesis was assessed by RNA-sequencing. In addition, we knocked out SlRNRL2 (a SlRNRL1 homologue) using CRISPR-Cas9 technology in the tomato genome, and we down-regulated SlRNRL2 expression in the genetic background of slrnrl1-1 using a tobacco rattle virus-induced gene silencing (VIGS) system. Key results The mutant slrnrl1 exhibited dwarf stature, chlorotic young leaves and smaller fruits. Physiological and transcriptomic analyses indicated that SlRNRL1 plays a crucial role in the regulation of cell cycle progression, chloroplast biogenesis and photosynthesis in tomato. The slrnrl2 mutant did not exhibit any visible phenotype. SlRNRL2 has a redundant function with SlRNRL1, and the double mutant slrnrl1slrnrl2 is lethal. Conclusions SlRNRL1 is essential for cell cycle progression, chloroplast biogenesis and photosynthesis. In addition, SlRNRL1 and SlRNRL2 possess redundant functions and at least one of these RNRLs is required for tomato survival, growth and development. [ABSTRACT FROM AUTHOR]

Sense mutations in several conserved modifiable sites of histone H3 have been found to be strongly correlated with multiple tissue-specific clinical cancers. These clinical site mutants acquire a distinctively new epigenetic role and mediate cancer evolution. In this study, we mimicked histone H3 at the 56th lysine (H3K56) mutant incorporation in mouse embryonic stem cells (mESCs) by lentivirus-mediated ectopic expression and analyzed the effects on replication and epigenetic regulation. The data show that two types of H3K56 mutants, namely H3 lysine 56-to-methionine (H3K56M) and H3 lysine 56-to-alanine (H3K56A), promote replication by recruiting more minichromosome maintenance complex component 3 and checkpoint kinase 1 onto chromatin compared with wild-type histone H3 and other site substitution mutants. Under this condition, the frequency of genomic copy number gain in H3K56M and H3K56A cells globally increases, especially in the Mycl1 region, a known molecular marker frequently occurring in multiple malignant cancers. Additionally, we found the disruption of H3K56 acetylation distribution in the copy-gain regions, which indicates a probable epigenetic mechanism of H3K56M and H3K56A. We then identified that H3K56M and H3K56A can trigger a potential adaptation to transcription; genes involved in the mitogen-activated protein kinase pathway are partially upregulated, whereas genes associated with intrinsic apoptotic function show obvious downregulation. The final outcome of ectopic H3K56M and H3K56A incorporation in mESCs is an enhanced ability to form carcinomas. This work indicates that H3K56 site conservation and proper modification play important roles in harmonizing the function of the replication machinery in mESCs. [ABSTRACT FROM AUTHOR]

Although lagging behind studies in humans and other mammals, studies of R-loops in plants have recently entered an exciting stage in which the roles of R-loops in gene expression, genome stability, epigenomic signatures, and plant development and stress responses are being elucidated. Here, we review the strengths and weaknesses of existing methodologies, which were largely developed for R-loop studies in mammals, and then discuss the potential challenges of applying these methodologies to R-loop studies in plants. We then focus on recent advances in the functional characterization of R-loops in Arabidopsis thaliana and rice. Recent studies in plants indicate that there are coordinated relationships between R-loops and gene expression, and between R-loops and epigenomic signatures that depend, in part, on the types of R-loops involved. Finally, we discuss the emerging roles of R-loops in plants and directions for future research. [ABSTRACT FROM AUTHOR]

Soybean molasses (SBM) is a byproduct of the manufacture of soy protein concentrate and has high energy value. This byproduct has a high potential for use in the nutrition of ruminant animals, mainly in the replacement of other energy feeds such as corn grain. The objective of this study was to evaluate the inclusion of SBM to replace corn grain up to 30% dry matter (DM) in the total diet on growth performance, feeding behavior, carcass characteristics, and meat quality of feedlot lambs (½ Santa Inês × ½ Dorper). Forty intact male lambs with an initial average body weight of 20.6 ± 2.5 kg and approximate age of 120 d were used. The animals were distributed in four treatments (0%, 10%, 20%, and 30% SBM), divided into five randomized blocks according to the initial weight and adapted for 16 d, with diets containing increasing concentrations of concentrate and SBM. Feeding behavior was analyzed at the beginning, middle, and final of the finishing period, and when animals reached 42 d on the finishing diet they were slaughtered. Data were evaluated using SAS software (version 9.4), by polynomial orthogonal contrasts, where the growth performance, carcass characteristics, and meat quality values were analyzed as randomized blocks, and the feeding behavior data as randomized blocks with a repeated measure over time. Significant differences were detected for the contrast 0 vs. SBM treatments, which the inclusion of SBM caused an increase (P ≤ 0.05) in ash intake but decreased the ether extract intake. The intake of DM in % body weight was higher for SBM treatments than 0% treatment (P ≤ 0.05). Feeding behavior, ruminating while lying down and drinking water presented a decreasing linear effect (P ≤ 0.05), and for feeding, efficiency increased with the addition of SBM (P ≤ 0.05). Fatty acids C14:0, C17:0, C17:1, C18:2n6c, C20:2, and C20:3n6 showed lower values ​​with the inclusion of SBM (P ≤ 0.05), while fatty acids C22:0 and C22:6n3 increased. The values ​​of n6 polyunsaturated fatty acids and n - 6/n-3 ratio were lower (P ≤ 0.05) for SBM treatments. The values ​​of total polyunsaturated fatty acids showed a decreasing linear effect (P ≤ 0.05) with the inclusion of SBM. The use of up to 30% SBM in DM did not impair animal growth performance and feeding behavior did not cause damages to carcass parameters and still made the meat healthier, improving the n - 6/n - 3 ratio, therefore can be used to feed finishing lambs. [ABSTRACT FROM AUTHOR]

Space radiation is characterized by high-linear energy transfer (LET) ionizing radiation. The relationships between the early biological effects of space radiation and the probability of cancer in humans are poorly understood. Bcl2 not only functions as a potent antiapoptotic molecule but also as an oncogenic protein that induces DNA replication stress. To test the role and mechanism of Bcl2 in high-LET space radiation-induced lung carcinogenesis, we created lung-targeting Bcl2 transgenic C57BL/6 mice using the CC10 promoter to drive Bcl2 expression selectively in lung tissues. Intriguingly, lung-targeting transgenic Bcl2 inhibits ribonucleotide reductase activity, reduces dNTP pool size and retards DNA replication fork progression in mouse bronchial epithelial cells. After exposure of mice to space radiation derived from 56iron, 28silicon or protons, the incidence of lung cancer was significantly higher in lung-targeting Bcl2 transgenic mice than in wild-type mice, indicating that Bcl2-induced DNA replication stress promotes lung carcinogenesis in response to space radiation. The findings provide some evidence for the relative effectiveness of space radiation and Bcl-2 at inducing lung cancer in mice. [ABSTRACT FROM AUTHOR]

Aim of the study: In this study, antibacterial and antibiofilm potential of sulphated polysaccharides (SPs) extracted from Chlamydomonas reinhardtii (Cr) was evaluated against Neisseria mucosa, Escherichia coli, Streptococcus sp. and Bacillus subtilis. Methods and Results: Antibacterial potential of Cr‐SPs was evaluated by agar‐cup diffusion, time‐kill and colony‐forming ability (CFU), minimum inhibitory and bactericidal concentration assays. Antibiofilm potential was evaluated by biofilm inhibition, eradication, extracellular‐DNA, metabolic activity and microscopy assays. Cr‐SPs at 0·5 mg ml−1 showed 34·52, 48·6, 66·1 and 55·6% reduced CFU in B. subtilis, Streptococcus, N. mucosa and E. coli respectively. Minimum inhibitory concentration of Cr‐SPs was as low as 480 μg ml−1 for Streptococcus, N. mucosa and 420 μg ml−1 for B. subtilis and E. coli. At 1 mg ml−1, Cr‐SPs showed 50% biofilm inhibition, whereas 4–8 mg ml−1 showed 100% inhibition. Cr‐SPs also effectively dissolved preformed biofilms. Dose‐dependent reduction in extracellular DNA revealed that Cr‐SPs interacts with the extra polymeric substance of the biofilm and destroys them. Light microscopy reconfirmed the above results. Conclusion: Cr‐SPs not only inhibited biofilm formation but also effectively dissolved preformed‐biofilms. Significance and Impact of the Study: The current study showed the promising potential of Cr‐SPs as antibiofilm agents. Further validation will help in developing Cr‐SPs as natural antibiotics against biofilm‐causing bacteria. [ABSTRACT FROM AUTHOR]

The activity of ribonucleotide reductase (RNR), which catalyses the transformation of four ribonucleoside diphosphates (NDPs) to their corresponding deoxyribonucleoside diphosphates (dNDPs), is the main determiner of the cellular concentration of dNTP pools and should be tightly coordinated with DNA synthesis and cell-cycle progression. Constitutively increased or decreased RNR activity interferes with DNA replication and leads to arrested cell cycle progression; however, the mechanisms underlying these disruptive effects in higher plants remain to be uncovered. In this study, we identified a RNR large subunit mutant, sistl1, in Setaria italica (foxtail millet), which exhibited growth retardation as well as striped leaf phenotype, i.e. irregularly reduced leaf vein distances and decreased chloroplast biogenesis. We determined that a Gly737 to Glu substitution occurring in the C-terminus of the SiSTL1 protein slightly affected its optimal function, leading in turn to the reduced expression of genes variously involved in the assembly and activation of the DNA pre-replicative complex, elongation of replication forks and S phase entry. Our study provides new insights into how SiSTL1 regulates plant growth, chloroplast biogenesis, and cell cycle progression in Poaceae crops. [ABSTRACT FROM AUTHOR]

The main objective of this study was to establish a protocol to validate urine spot samples to estimate N excretion and microbial synthesis in goat and sheep; and to study factors that affect daily creatinine and purine derivatives (PD) urinary excretion. Also a performance trial was carried out to compare goat and sheep slaughtered after different feedlot periods. Twelve Boer goats (20.6 kg ± 3.4 initial BW) and 12 Dorper sheep (18.4 kg ± 2.3 initial BW), all 4-mo-old, males, were used. Eight animals (4 goats and 4 sheep) were randomly allocated to be slaughtered at 28, 56, and 84 d in feedlot. The experiment was conducted in a completely randomized design in a 2 × 3 factorial scheme, in which the factors were both species and the 3 feedlot periods. Diet consisted of 50% sorghum silage and 50% concentrate on a DM basis. Nutrient intake was higher (P < 0.01) for sheep than goats. Apparent digestibility of nutrients was similar (P > 0.05) in both species. Sheep had greater (P < 0.01) ADG and final BW than goats. Fat deposition and fat:muscle ratio was higher (P < 0.01) in sheep carcasses. Sheep had higher N urinary (P = 0.02) excretion and N retention (g/d; P < 0.01) than goats. Urinary N excretion increased linearly (P < 0.01) in response to feedlot period. However, feedlot did not affect (P = 0.20) N retention, but linearly reduced the relationship between N retained and ingested (P = 0.04) or apparently digested (P < 0.01). Microbial efficiency (P > 0.05) did not differ between species. Creatinine excretion (C mg/d; P < 0.01) was higher in sheep than goats. Purine derivatives (Ŷ) were related closely with OM intake (Ŷ = 0.013±0.0007X; r² = 94). A difference (P < 0.01) was found between the allometric model for creatinine excretion (Ŷ) and muscle weight (X) for both species, and the following equations were obtained: Ŷ = 89.04(±31.44)X0.9797(±0.16) for goats and Ŷ = 109.8(±47.50)X0.8002(±0.20) for sheep. Creatinine concentration was greater during nocturnal than diurnal periods, with lower diurnal fluctuations. Sampling time did not affect (P = 0.27) the PD:C ratio. The urea (U):C ratio was higher (P < 0.01) in sheep than goats, and was also higher (P < 0.01) during diurnal than nocturnal sampling periods. Our results suggest that it is necessary to take 2 and 3 spot urine samples after feeding to estimate N compounds excretions in goats and sheep, respectively. [ABSTRACT FROM AUTHOR]

The eyes of scallops form images using a concave spherical mirror and contain two separate retinas, one layered on top of the other. Behavioral and electrophysiological studies indicate that the images formed by these eyes have angular resolutions of about 2°. Based on previous ray-tracing models, it has been thought that the more distal of the two retinas lies near the focal point of the mirror and that the proximal retina, positioned closer to the mirror at the back of the eye, receives light that is out-of-focus. Here, we propose three mechanisms through which both retinas may receive focused light: (1) chromatic aberration produced by the lens may cause the focal points for longer and shorter wavelengths to fall near the distal and proximal retinas, respectively; (2) focused light from near and far objects may fall on the distal and proximal retinas, respectively; and (3) the eyes of scallops may be dynamic structures that change shape to determine which retina receives focused light. To test our hypotheses, we used optical coherence tomography (OCT), a method of near-infrared optical depth-ranging, to acquire virtual cross-sections of live, intact eyes from the bay scallop Argopecten irradians. Next, we used a custom-built ray-tracing model to estimate the qualities of the images that fall on an eye's distal and proximal retinas as functions of the wavelengths of light entering the eye (400-700 nm), object distances (0.01-1 m), and the overall shape of the eye. When we assume 550nm wavelength light and object distances greater than 0.01 m, our model predicts that the angular resolutions of the distal and proximal retinas are 2° and 7°, respectively. Our model also predicts that neither chromatic aberration nor differences in object distance lead to focused light falling on the distal and proximal retinas simultaneously. However, if scallops can manipulate the shapes of their eyes, perhaps through muscle contractions, we speculate that they may be able to influence the qualities of the images that fall on their proximal retinas and--to a lesser extent--those that fall on their distal retinas as well. [ABSTRACT FROM AUTHOR]