Effects of Competition and Dispersal on the Recruitment of the Annual Kelp Nereocystis luetkeana

In central California, the role of algal assemblages on the recruitment of the canopy producing annual kelp Nereocystis luetkeana was examined by experimentally manipulating canopy and understory algae within 1) a Macrocysits bed and 2) a Nereocystis bed. Nereocystis reproductive material was introduced in some plots to examine the role of dispersal distance on recruitment. Nereocystis recruitment at both sites was significantly higher during spring compared to recruitment observed later in the study. Recruitment continued throughout the fall, however, suggesting a broad recruitment window. Recruitment success increased dramatically when understory algae were removed. Presence of a canopy (Nereocystis or Macrocystis) did not affect Nereocystis recruitment, suggesting that Nereocystis was not directly competitively inferior to Macrocystis. Greater recruitment was observed in areas seeded with Nereocystis propagules. Ultimately, recruitment of Nereocystis was controlled by understory algal assemblages and by the relatively short dispersal distance of its propagules. Additionally, the broad recruitment window for Nereocystis described here suggests that summer recruits can contribute to population resilience to late spring disturbances. This study indicates that given sufficient disturbance to the benthos and ample propagule supply, Nereocystis should be able to recruit and colonize new areas, regardless of the presence of Macrocystis

Structural basis for the disaggregase activity and regulation of Hsp104

The Hsp104 disaggregase is a two-ring ATPase machine that rescues various forms of non-native proteins including the highly resistant amyloid fibers. The structural-mechanistic underpinnings of how the recovery of toxic protein aggregates is promoted and how this potent unfolding activity is prevented from doing collateral damage to cellular proteins are not well understood. Here, we present structural and biochemical data revealing the organization of Hsp104 from Chaetomium thermophilum at 3.7 angstrom resolution. We show that the coiled-coil domains encircling the disaggregase constitute a 'restraint mask' that sterically controls the mobility and thus the unfolding activity of the ATPase modules. In addition, we identify a mechanical linkage that coordinates the activity of the two ATPase rings and accounts for the high unfolding potential of Hsp104. Based on these findings, we propose a general model for how Hsp104 and related chaperones operate and are kept under control until recruited to appropriate substrates

Serine ADP-ribosylation in Drosophila provides insights into the evolution of reversible ADP-ribosylation signalling

In the mammalian DNA damage response, ADP-ribosylation signalling is of crucial importance to mark sites of DNA damage as well as recruit and regulate repairs factors. Specifically, the PARP1:HPF1 complex recognises damaged DNA and catalyses the formation of serine-linked ADP-ribosylation marks (mono-Ser-ADPr), which are extended into ADP-ribose polymers (poly-Ser-ADPr) by PARP1 alone. Poly-Ser-ADPr is reversed by PARG, while the terminal mono-Ser-ADPr is removed by ARH3. Despite its significance and apparent evolutionary conservation, little is known about ADP-ribosylation signalling in non-mammalian Animalia. The presence of HPF1, but absence of ARH3, in some insect genomes, including Drosophila species, raises questions regarding the existence and reversal of serine-ADP-ribosylation in these species. Here we show by quantitative proteomics that Ser-ADPr is the major form of ADP-ribosylation in the DNA damage response of Drosophila melanogaster and is dependent on the dParp1:dHpf1 complex. Moreover, our structural and biochemical investigations uncover the mechanism of mono-Ser-ADPr removal by Drosophila Parg. Collectively, our data reveal PARP:HPF1-mediated Ser-ADPr as a defining feature of the DDR in Animalia. The striking conservation within this kingdom suggests that organisms that carry only a core set of ADP-ribosyl metabolising enzymes, such as Drosophila, are valuable model organisms to study the physiological role of Ser-ADPr signalling

The oxidoreductase PYROXD1 uses NAD(P)+ as an antioxidant to sustain tRNA ligase activity in pre-tRNA splicing and unfolded protein response

The tRNA ligase complex (tRNA-LC) splices precursor tRNAs (pre-tRNA), and Xbp1-mRNA during the unfolded protein response (UPR). In aerobic conditions, a cysteine residue bound to two metal ions in its ancient, catalytic subunit RTCB could make the tRNA-LC susceptible to oxidative inactivation. Here, we confirm this hypothesis and reveal a co-evolutionary association between the tRNA-LC and PYROXD1, a conserved and essential oxidoreductase. We reveal that PYROXD1 preserves the activity of the mammalian tRNA-LC in pre-tRNA splicing and UPR. PYROXD1 binds the tRNA-LC in the presence of NAD(P)H and converts RTCB-bound NAD(P)H into NAD(P)+, a typical oxidative co-enzyme. However, NAD(P)+ here acts as an antioxidant and protects the tRNA-LC from oxidative inactivation, which is dependent on copper ions. Genetic variants of PYROXD1 that cause human myopathies only partially support tRNA-LC activity. Thus, we establish the tRNA-LC as an oxidation-sensitive metalloenzyme, safeguarded by the flavoprotein PYROXD1 through an unexpected redox mechanism

Messianism and Modernity. Commentary to the Liturgy of History

In his recent book Liturgia dziejów [Liturgy of History], Paweł Rojek argues that Karol Wojtyła was to a large extent influenced by Polish Messianism. Although Rojek’s argument centres around this rather historical thesis, his book is essential reading not only for students of John Paul II’s legacy but anyone interested in the relationship between Christianity and modernity. It is so, because Polish Messianism, according to Rojek, was an early project of Christian modernity. By taking inspiration from the Messianists, Wojtyła was able to combine religious perspective with modern anthropocentrism.In his recent book Liturgia dziejów [Liturgy of History], Paweł Rojek argues that Karol Wojtyła was to a large extent influenced by Polish Messianism. Although Rojek’s argument centres around this rather historical thesis, his book is essential reading not only for students of John Paul II’s legacy but anyone interested in the relationship between Christianity and modernity. It is so, because Polish Messianism, according to Rojek, was an early project of Christian modernity. By taking inspiration from the Messianists, Wojtyła was able to combine religious perspective with modern anthropocentrism

Messianism and Modernity. Commentary to the Liturgy of History

In his recent book Liturgia dziejów [Liturgy of History], Paweł Rojek argues that Karol Wojtyła was to a large extent influenced by Polish Messianism. Although Rojek’s argument centres around this rather historical thesis, his book is essential reading not only for students of John Paul II’s legacy but anyone interested in the relationship between Christianity and modernity. It is so, because Polish Messianism, according to Rojek, was an early project of Christian modernity. By taking inspiration from the Messianists, Wojtyła was able to combine religious perspective with modern anthropocentrism

Middle East - biggest global armament market.

In this paper I want to show the most important purchases of arms carried by the state of the Middle East in the years 1992 - 2010. I would also like to show key relationships between suppliers and customers.This work includes 17 countries. This is the 16 Arab states: Saudi Arabia, Algeria, Bahrain, Egypt, Iraq, Yemen, Jordan, Qatar, Kuwait, Lebanon, Libya, Morocco, Oman, Syria, Tunisia, UAE and Israel.In this paper I presented all purchases ​​by the state of the Middle East after 1991. This applies to both new weapons, produced on special order for a particular state, as well as weapons used, from the mobilization of surplus countries in both Western and owned before 1991 to the Warsaw Pact.As a basic support, I used database of Global Security, Jane's IHS: Defence & Security Intelligence & Analysis, Defense News, Israel Defense and Altair. A very good source of information were also websites of defense companies, like Lockheed Martin, Boeing.W swojej pracy chciałbym pokazać najważniejsze zakupy zbrojeniowe zrealizowane przez państwa Bliskiego Wschodu w latach 1992 – 2010. Chciałbym również wykazać najważniejsze powiązania, zależności między dostawcami a odbiorcami. Praca ta obejmuje 17 państw. Jest to 16 państw arabskich: Arabia Saudyjska, Algieria, Bahrajn, Egipt, Irak, Jemen, Jordania, Katar, Kuwejt, Liban, Libia, Maroko, Oman, Syria, Tunezja, ZEA oraz Izrael. W niniejszej pracy przedstawiłem wszystkie zakupy dokonane przez państwa Bliskiego Wschodu po roku 1991. Dotyczy to uzbrojenia zarówno nowego, wyprodukowanego na specjalne zamówienie konkretnego państwa, jak i uzbrojenie używane, pochodzące z nadwyżek mobilizacyjnych państw zarówno zachodnich jak i należących przed 1991 rokiem do Układu Warszawskiego.Jako podstawowe wsparcie, wykorzystywałem bazy danych Globar Security, IHS Jane’s: Defence & Security Intelligence & Analysis, Defense News, Izrael Defense a także Altair. Bardzo dobrym źródłem informacji okazały się również strony firm i koncernów zbrojeniowych, jak choćby Lockheed Martin, Boeing