Spatio-temporal dynamics of multi-trophic communities reveal ecosystem-wide functional reorganization

Large-scale alterations in marine ecosystems as a response to environmental and anthropogenic pressures have been documented worldwide. Yet, these are primarily investigated by assessing abundance fluctuations of a few dominant species, which inadequately reflect ecosystem-wide changes. In addition, it is increasingly recognized that it is not species identity per se, but their traits that determine environmental responses, biological interactions and ecosystem functioning. In this study, we investigated long-term, spatio-temporal variability in trait composition across multiple organism groups to assess whether functional changes occur in a similar way across trophic levels and whether shifts in trait composition link to environmental change. We combined extensive trait datasets with long-term surveys (30–40 yr) of four organism groups (phytoplankton, zooplankton, benthic invertebrates and fish) in three environmentally distinct areas of a large marine ecosystem. We found similar temporal trajectories in the community weighted mean trait time-series of the different trophic groups, revealing ecosystem-wide functional changes. The traits involved and their dynamics differed between areas, concurrent with climate-driven changes in temperature and salinity, as well as more local dynamics in nutrients and oxygen. This finding highlights the importance of considering both global climate, as well as local external drivers when studying ecosystem changes. Using a multi-trophic trait-based approach, our study demonstrates the importance of integrating community functional dynamics across multiple trophic levels to capture ecosystem-wide responses which could, ultimately, help moving towards a holistic understanding, assessment and management of marine ecosystems.     

Beneficial Effect of Lantibiotic Nisin in Rabbit Husbandry

Nisin is a bacteriocin marketed as Nisaplin. The aim of our work was to test its in vivo effect in a rabbit model; its effect on phagocytic activity (PA) and morphometry has not so far been studied. Post-weaning rabbits (48), 5 weeks old (both sexes, Hycole breed), were divided into the experimental (E) and the control groups (C), 24 animals in each. They were fed a commercial diet with access to water ad libitum. Rabbits in E had nisin additionally administered to their drinking water (500 IU-20 μg per animal/day) for 28 days. The experiment lasted 42 days. On day 28, significant decrease in coagulase-positive (CoPS) staphylococci and coliforms was noted (p < 0.01) in faeces of group E compared with C. Pseudomonads and clostridiae were also significantly reduced (p < 0.001; p < 0.05) and slight decrease was also in CoNS and enterococci. On day 42, coliforms were still significantly reduced (p < 0.001) in faeces; slight decrease in CoPS and pseudomonads was noted. In the caecum, significant decrease in pseudomonads (p < 0.05) was noted on day 28; slight decrease in coliforms. In the appendix slight decrease in coliforms, pseudomonads was obtained on both days. PA was increased significantly in E on days 28, 42 (p < 0.001). Biochemical parameters were not influenced; nor were volatile fatty acids or lactic acid in the chymus. Nisin application did not evoke oxidative stress. In group E, an increase in average body weight gain (about 9.4 %) was noted. The villus height/crypt depth ratio was not influenced; that is, resorption surface and functionality of mucosa were not influenced.     

Enterococcus faecium AL 41: Its Enterocin M and Their Beneficial Use in Rabbits Husbandry

Enterococci are ubiquitous microbiota constituting a large proportion of autochthonous microflora in animals. Some produce bacteriocins mostly enterocins; some of bacteriocin-producing strains also possess probiotic properties. Enterococcus faecium AL 41, Ent M-producing strain was tested for beneficial effect in rabbits. Five-week-old animals (72, Hycole) were divided into experimental groups (E1, E2) and control (C); 24 animals in each. Rabbits in E1 were administered AL 41 (500???l per animal/day, 10⁹?cfu/ml) in water for 21?days; rabbits in E2 were administered Ent M (50???l/animal/day, activity 12,800?AU/ml) in water for 21?days. Rabbits in C fed a commercial diet. The experiment lasted 42?days. Sampling of faeces and blood was provided on day 0?C1 and 21, 42; 3 animals per group were slaughtered. Caecum and appendix were separated. AL 41 colonized rabbits intestines?<1.0 (log10) cfu/g, but stimulation of immunity was noted (P?<?0.01; P?<?0.001). Antimicrobial activity of both was noticed in faeces and/or caecum against pseudomonads. Significant decrease of coliform bacteria in faeces of E1 was noted on day 42 comparing with E2 (P?<?0.05). On day 21, S. aureus cells were not detected in E1, E2. On day 42, S. aureus was not found in E2; in E1 their counts were?<1.0?cfu/g, while in C it was in the count more than 1.0?cfu/g. In appendix, on day 21, significant decrease of not specified bacteria was found in E1, E2 comparing with C (P?<?0.01). Administration of additives has not evoked oxidative stress. Biochemical parameters were not influenced. Higher average daily weight gains were detected by both, AL 41 and Ent M.     

Raf-1 levels determine the migration rate of primary endometrial stromal cells of patients with endometriosis

Endometriosis is a disease characterized by the localization of endometrial tissue outside the uterine cavity. The differences observed in migration of human endometrial stromal cells (hESC) obtained from patients with endometriosis versus healthy controls were proposed to correlate with the abnormal activation of Raf-1/ROCKII signalling pathway. To evaluate the mechanism by which Raf-1 regulates cytoskeleton reorganization and motility, we used primary eutopic (Eu-, n = 16) and ectopic (Ec-, n = 8; isolated from ovarian cysts) hESC of patients with endometriosis and endometriosis-free controls (Co-hESC, n = 14). Raf-1 siRNA knockdown in Co- and Eu-hESC resulted in contraction and decreased migration versus siRNA controls. This phenotype was reversed following the re-expression of Raf-1 in these cells. Lowest Raf-1 levels in Ec-hESC were associated with hyperactivated ROCKII and ezrin/radixin/moesin (E/R/M), impaired migration and a contracted phenotype similar to Raf-1 knockdown in Co- and Eu-hESC. We further show that the mechanism by which Raf-1 mediates migration in hESC includes direct myosin light chain phosphatase (MYPT1) phosphorylation and regulation of the levels of E/R/M, paxillin, MYPT1 and myosin light chain (MLC) phosphorylation indirectly via the hyperactivation of ROCKII kinase. Furthermore, we suggest that in contrast to Co-and Eu-hESC, where the cellular Raf-1 levels regulate the rate of migration, the low cellular Raf-1 content in Ec-hESC, might ensure their restricted migration by preserving the contracted cellular phenotype. In conclusion, our findings suggest that cellular levels of Raf-1 adjust the threshold of hESC migration in endometriosis.     

Unique frequencies of HFE gene variants in Roma/Gypsies

The aim of this study was to assess the frequencies of three hemochromatosis gene (HFE) mutations in ethnic Roma/Gypsies in Slovakia. A cohort of 367 individuals representing general population and not preselected for health status was genotyped by TaqMan real-time PCR assay for C282Y, H63D and S65C mutations in HFE gene. A unique genetic profile was revealed: C282Y is found in the highest frequency of all Central European countries (4.90%), while the frequency of H63D mutation (4.09%) is lower than any reported in Europe so far. S65C mutation was not present in the cohort. These mutation frequencies can be explained rather by gene influx and genetic isolation than by genetic inheritance from a former Roma/Gypsy homeland.     

Synthesis,structural characterization and biological activity of novel Knoevenagel condensates on DLD-1 human colon carcinoma

Biologically active Knoevenagel condensates (1–14) of diarylheptanoids: 1,7-bis(3-methoxy-4-hydroxyphenyl)hepta-1,7-diene-3,5-dione and 1,7-bis(3-ethoxy-4-hydroxyphenyl)hepta-1,7-diene-3,5-dione, were synthesized and structurally characterized. Compounds 1–14 exhibited cytotoxicity against colon carcinoma cells, and their antiproliferative effect was associated with a significant decrease of multidrug resistance proteins. One of the underlying mechanisms of these effects is the reduction of intracellular and extracellular SOD enzymes by compounds 1, 12 and 14, which render the tumor cells more vulnerable to oxidative stress.