Colony formation was the first step towards evolution of multicellularity in many macroscopic organisms. Dictyostelid social amoebas have used this strategy for over 600 Myr to form fruiting structures of increasing complexity. To understand in which order multicellular complexity evolved, we measured 24 phenotypic characters over 99 dictyostelid species. Using phylogenetic comparative methods, we show that the last common ancestor (LCA) of Dictyostelia probably erected small fruiting structures directly from aggregates. It secreted cAMP to coordinate fruiting body morphogenesis, and another compound to mediate aggregation. This phenotype persisted up to the LCAs of three of the four major groups of Dictyostelia. The group 4 LCA co-opted cAMP for aggregation and evolved much larger fruiting structures. However, it lost encystation, the survival strategy of solitary amoebas that is retained by many species in groups 1–3. Large structures, phototropism and a migrating intermediate ‘slug’ stage coevolved as evolutionary novelties within most groups. Overall, dictyostelids show considerable plasticity in the size and shape of multicellular structures, both within and between species. This probably reflects constraints placed by colonial life on developmental control mechanisms, which, depending on local cell density, need to direct from 10 to a million cells into forming a functional fructification.

Cullin-RING ligases (CRLs) are ubiquitin E3 enzymes with variable substrate-adaptor and -receptor subunits. All CRLs are activated by modification of the cullin subunit with the ubiquitin-like protein Nedd8 (neddylation). The protein CAND1 (Cullin-associated-Nedd8-dissociated-1) also promotes CRL activity, even though it only interacts with inactive ligase complexes. The molecular mechanism underlying this behaviour remains largely unclear. Here, we find that yeast SCF (Skp1-Cdc53-F-box) Cullin-RING complexes are remodelled in a CAND1-dependent manner, when cells are switched from growth in fermentable to non-fermentable carbon sources. Mechanistically, CAND1 promotes substrate adaptor release following SCF deneddylation by the COP9 signalosome (CSN). CSN-or CAND1-mutant cells fail to release substrate adaptors. This delays the formation of new complexes during SCF reactivation and results in substrate degradation defects. Our results shed light on how CAND1 regulates CRL activity and demonstrate that the cullin neddylationdeneddylation cycle is not only required to activate CRLs, but also to regulate substrate specificity through dynamic substrate adaptor exchange.

The replication time of Saccharomyces cerevisiae telomeres responds to TG1–3 repeat length, with telomeres of normal length replicating late during S phase and short telomeres replicating early. Here we show that Tel1 kinase, which is recruited to short telomeres, specifies their early replication, because we find a tel1Δ mutant has short telomeres that nonetheless replicate late. Consistent with a role for Tel1 in driving early telomere replication, initiation at a replication origin close to an induced short telomere was reduced in tel1Δ cells, in an S phase blocked by hydroxyurea. The telomeric chromatin component Rif1 mediates late replication of normal telomeres and is a potential substrate of Tel1 phosphorylation, so we tested whether Tel1 directs early replication of short telomeres by inactivating Rif1. A strain lacking both Rif1 and Tel1 behaves like a rif1Δ mutant by replicating its telomeres early, implying that Tel1 can counteract the delaying effect of Rif1 to control telomere replication time. Proteomic analyses reveals that in yku70Δ cells that have short telomeres, Rif1 is phosphorylated at Tel1 consensus sequences (S/TQ sites), with phosphorylation of Serine-1308 being completely dependent on Tel1. Replication timing analysis of a strain mutated at these phosphorylation sites, however, suggested that Tel1-mediated phosphorylation of Rif1 is not the sole mechanism of replication timing control at telomeres. Overall, our results reveal two new functions of Tel1 at shortened telomeres: phosphorylation of Rif1, and specification of early replication by counteracting the Rif1-mediated delay in initiation at nearby replication origins.

The Rif1 protein negatively regulates telomeric TG repeat length in the budding yeast Saccharomyces cerevisiae, but how it prevents telomere over-extension is unknown. Rif1 was recently shown to control DNA replication by acting as a Protein Phosphatase 1 (PP1)-targeting subunit. Therefore, we investigated whether Rif1 controls telomere length by targeting PP1 activity. We find that a Rif1 mutant defective for PP1 interaction causes a long-telomere phenotype, similar to that of rif1Δ cells. Tethering PP1 at a specific telomere partially substitutes for Rif1 in limiting TG repeat length, confirming the importance of PP1 in telomere length control. Ablating Rif1–PP1 interaction is known to cause precocious activation of telomere-proximal replication origins and aberrantly early telomere replication. However, we find that Rif1 still limits telomere length even if late replication is forced through deletion of nearby replication origins, indicating that Rif1 can control telomere length independent of replication timing. Moreover we find that, even at a de novo telomere created after DNA synthesis during a mitotic block, Rif1–PP1 interaction is required to suppress telomere lengthening and prevent inappropriate recruitment of Tel1 kinase. Overall, our results show that Rif1 controls telomere length by recruiting PP1 to directly suppress telomerase-mediated TG repeat lengthening.

Septic infections in patients treated in intensive care units show the highest mortality rates. Despite advances in treatment methods, there is still no therapy available to efficiently reduce the excessive inflammatory response, which can increase the risk of multiple organ failure. One of the ways to discover new, more efficient treatment methods involves regulating the mechanisms of inflammatory response to a massive infection. Toll-like receptors (TLRs) that recognize pathogen-associated molecular patterns play a significant role in innate antibacterial and inflammatory responses. The regulatory impact of immunonutrition on TLR expression in septic patients seems to be a promising research direction. This paper presents the main mechanisms for the innate immune response to lipopolysaccharide, based on the research results for both TLR-dependent and independent signaling pathways. Special emphasis was put on the research results for the TLR-dependent immune response and the anti-bacterial/anti-inflammatory response after applying immunonutrition with increased concentrations of glutamine and unsaturated fatty acids.

Aim of the study: The purpose of the study was to investigate the effect of pancreatic cancer and preoperative enteral immune-enhancing diet (immunonutirtion)

Septic infections in malnourished surgical patients show the highest morbidity and mortality rate. The attempt to correct postoperative immune and nutritional disorders by introducing immune-enhancing nutrition (immunonutrition) is a promising way of improving outcome, but as yet little is known about the mechanisms of correcting an extensive postoperative inflammatory response (systemic inflammatory response syndrome [SIRS]) to a massive infection using this type of nutrition. A significant role in the innate antibacterial and inflammatory response is played by Toll-like receptors (TLRs) that recognize pathogen-associated molecular patterns (PAMPs). The regulatory impact of immunonutrition on TLR expression in surgical septic patients seems to be a new research direction. In this paper special emphasis was put on clinical trials and the research results for the TLR-dependent immune response and anti-bacterial/anti-inflammatory response applying immu nomo dulatory nutrition with increased concentrations of glutamine and unsaturated fatty acids. StreszczenieZakażenia septyczne w grupie niedożywionych pacjentów chirurgicznych obarczone są najwyższym wskaźnikiem chorobowości i śmiertelności. Korekcja pooperacyjnych zaburzeń odporności i niedożywienia poprzez żywienie immunomodulujące jest obiecującą metodą uzyskania lepszych wyników leczenia, ale nadal niewiele wiadomo o mechanizmach regulacji zwiększonej pooperacyjnej odpowiedzi zapalnej (systemic inflammatory response syndrome -SIRS) na masywne zakażenie za pomocą tego typu terapii. Istotne znaczenie w regulacji wrodzonej odpowiedzi przeciwbakteryjnej i przeciwzapalnej mają receptory TLRs (Toll-like receptors), rozpoznające związane z patogenami wzory molekularne (pathogen-associated molecular patterns -PAMPs). Ocena regulacyjnego wpływu żywienia immunomodulacyjnego na ekspresję receptorów TLR u septycznych pacjentów chirurgicznych jest nowym kierunkiem badań naukowych. W przedstawionej pracy szczególną uwagę zwrócono na wyniki badań klinicznych i eksperymentalnych dotyczące regulacji zależnej od TLRs odpowiedzi przeciwbakteryjnej/przeciwzapalnej za pomocą żywienia immunomodulacyjnego, zawierającego zwiększone stężenia glutaminy i nienasyconych kwasów tłuszczowych.

The mechanisms of correcting immune disorders in patients with pancreatic cancer requiring major surgery procedures by introducing perioperative immune-enhancing diet (immunonutrition) are still unclear. The purpose of our study was to investigate the effect of pancreatic cancer, extensive surgery and immunonutrition versus enteral standard nutrition on the apoptotic signaling pathways. The randomized studies were performed in 72 patients before and after pancreatic cancer resection with preoperative standard (Group I) or enteral immunonutrition (Group II). The expressions of Bcl-2, Bax, caspases-3, -9, NF-κB, PARP-1/89 kDa, TNFR1/CD120a and Fas/CD95 in peripheral blood lymphocytes were assessed by western blot analysis and flow cytometry before and on day 1, 3 and 7 after surgery. In malnourished patients before and after surgery, the expression of Bcl-2, Bax, NF-κB, PARP-1 was significantly lower, whereas the expression of caspases, as well as the percentage of cells with death receptors were significantly higher when compared with the control group. There was no difference in Bcl-2, Bax and PARP-1 expression between the control group and the patients with normal nutritional status (Group III) before surgery. In comparison to the standard nutrition, the preoperative immunonutrition increased the Bcl-2 and Bax expression inconsiderably but significantly increased the percentage of CD95- and CD120a-positive lymphocytes after surgery. In malnourished patients with pancreatic cancer, the overwhelming expression of caspases and the decrease expression of anti-apoptotic proteins may lead to inappropriate lymphocyte apoptosis and higher cell depletion. The preoperative enteral immunonutrition prevents the postoperative decrease in lymphocyte subsets, but a higher level of lymphocyte susceptibility to undergo accelerated apoptosis can also be considered.