Antimicrobial metabolites produced by an intertidal Acremonium furcatum

In a screening for antimicrobial metabolites, amides of D-allo- and L-isoleucine derivatives were isolated from the culture of a marine strain of Acremonium furcatum. Structural elucidation of these compounds was performed by analysis of spectroscopic data and confirmed by synthesis. All of the compounds, natural and synthetic intermediates, were bioassayed against bacteria and phytopathogenic fungi, with many showing remarkable antifungal activities.     

Description of nine South American species of the genus Neralsia cameron, with low scutellar carina (Hymenoptera: Cynipoidea: Figitidae)

In this study a total of nine new species of the genus Neralsia are described for South America: N. desantisi Jiménez & Pujade-Villar n. sp., N. equilatera Jiménez & Pujade-Villar n. sp., N. hermafrodita Jiménez & Pujade-Villar n. sp., N. marioi Jiménez & Pujade-Villar n. sp., N. moisesi Jiménez & Pujade-Villar n. sp., N. obelix Jiménez & Pujade-Villar n. sp., N. parafossulata Jiménez & Pujade-Villar n. sp., N. pseudoneralsia Jiménez & Pujade-Villar n. sp. and N. rauli Jiménez & Pujade-Villar n. sp., all of them have in common the low carina separating the scutellar foveae. Other six known Neralsia species, N. albipennis (Kieffer), N. bogotensis (Kieffer), N. flavidipennis (Kieffer), N. fossulata (Kieffer), N. pilosa (Borgmeier) and N. striaticeps (Kieffer) have the same scutellar character. The morphological characters to differentiate all mentioned species are presented.     

New pseudopeptidic cross-linker containing urea bonds: study of its degradation routes in aqueous media using capillary electrophoresis-mass spectrometry

An accelerated degradation study has been performed on TLT, a pseudopeptide that includes esterified tyrosine and lysine linked by urea bonds, as well as on their derivatives, i.e., a dimethacrylic cross-linker (DMTLT) and a poly(dimethylacrylamide) cross-linked with DMTLT. The monitoring and analytical characterization has been carried out by capillary electrophoresis-mass spectrometry (CE-MS), using ion trap and time-of-flight MS analyzers. Several degradative species have been identified, and a kinetic analysis of the variation of their concentration with time has been obtained. During the initial stages of degradation, there is a competition between hydrolysis of the ester groups and cyclization by nucleophilic attack of the NHs of the urea groups to the carbonyl ester group. At higher degradation time (weeks or months), evidences of backbone breakdown, including urea hydrolysis, have been found.     

Cheap and Long‐Life Reusable Polymer for Asymmetric Organozinc Catalysis Based on Camphor‐Derived Hydroxyamides

Polystyrene grafted with a chiral zinc‐complexing camphor‐derived N,N‐disubstituted hydroxyamide is proposed as a new type of functional polymer of high reusability for the development of sustainable organozinc‐catalyzed asymmetric reactions. The main goal of this new functional polymer is the ease of the hydroxyamide‐moiety preparation (cheap chiral ligand obtained straightforwardly from an enantiopure starting material coming from the chiral pool), as well as its chemical robustness when compared with other related zinc‐complexing functional groups. The latter allows the polymer to be active after multiple applications, without significant loss of its catalytic activity. This fact is exemplified by the design and preparation of a polymer functionalized with a bis(hydroxyamide) proved previously as active in the homogeneous enantioselective addition of diethylzinc to aldehydes. The result is a cheap functional polymer with a very high reusability (the enantioselectivity and chemical yield are maintained practically constant after 20 applications). Additionally, a methodology for the multicycle use of these functional polymers is presented. Chirality, 2012. © 2012 Wiley Periodicals, Inc.     

Aquatic metabolism short-term response to the flood pulse in a Mediterranean floodplain

The pulsing of river discharge affects biodiversity and productivity of whole river–floodplain ecosystems, triggering the transport, storage and processing of carbon. In this study we investigate the short-term changes in water chemistry and net pelagic metabolism (NEP) in two floodplain lakes in response to a flood pulse. The two oxbow lakes investigated in the floodplain of the Mediterranean Ebro River (NE Spain) showed a clear temporal shift in their metabolic balance, controlled by the river discharge and associated changes in water physical and chemical characteristics. Water chemistry (turbidity, water organic matter, chlorophyll a and nutrients concentration) returned to pre-flood values after 4 days, highlighting the resilience of the ecosystem to flood pulses. Lake NEP was depressed before and during floods to a minimum of −34 mg O₂ m⁻³ h⁻¹, and increased after the flood pulse to a maximum of +463 mg O₂ m⁻³ h⁻¹. The phytoplankton assemblage showed before and after floods a replacement of autotrophic species (e.g. Chlorophyceans) by mixotrophic organisms (e.g. Cryptophyceans, Euglenoids). A linear mixed effects model identified abiotic factors, particularly temperature and river discharge, as significant predictors of the net aquatic metabolism and community respiration during flood conditions. Our results suggest that the role of the Ebro floodplain lakes as sources or sinks of C is complex and relative to the time scale investigated, depending strongly on the river discharge dynamics and the transport of limiting nutrients (phosphorus).     

Daily scheduled high fat meals moderately entrain behavioral anticipatory activity, body temperature, and hypothalamic c-Fos activation

When fed in restricted amounts, rodents show robust activity in the hours preceding expected meal delivery. This process, termed food anticipatory activity (FAA), is independent of the light-entrained clock, the suprachiasmatic nucleus, yet beyond this basic observation there is little agreement on the neuronal underpinnings of FAA. One complication in studying FAA using a calorie restriction model is that much of the brain is activated in response to this strong hunger signal. Thus, daily timed access to palatable meals in the presence of continuous access to standard chow has been employed as a model to study FAA in rats. In order to exploit the extensive genetic resources available in the murine system we extended this model to mice, which will anticipate rodent high fat diet but not chocolate or other sweet daily meals (Hsu, Patton, Mistlberger, and Steele; 2010, PLoS ONE e12903). In this study we test additional fatty meals, including peanut butter and cheese, both of which induced modest FAA. Measurement of core body temperature revealed a moderate preprandial increase in temperature in mice fed high fat diet but entrainment due to handling complicated interpretation of these results. Finally, we examined activation patterns of neurons by immunostaining for the immediate early gene c-Fos and observed a modest amount of entrainment of gene expression in the hypothalamus of mice fed a daily fatty palatable meal.     

TLC1 RNA nucleo-cytoplasmic trafficking links telomerase biogenesis to its recruitment to telomeres

The yeast telomerase holoenzyme, which adds telomeric repeats at the chromosome ends, is composed of the TLC1 RNA and the associated proteins Est1, Est2 and Est3. To study the biogenesis of telomerase in endogenous conditions, we performed fluorescent in situ hybridization on the native TLC1 RNA. We found that the telomerase RNA colocalizes with telomeres in G1- to S-phase cells. Strains lacking any one of the Est proteins accumulate TLC1 RNA in their cytoplasm, indicating that a critical stage of telomerase biogenesis could take place outside of the nucleus. We were able to demonstrate that endogenous TLC1 RNA shuttles between the nucleus and the cytoplasm, in association with the Crm1p exportin and the nuclear importins Mtr10p-Kap122p. Furthermore, nuclear retention of the TLC1 RNA is impaired in the absence of yKu70p, Tel1p or the MRX complex, which recruit telomerase to telomeres. Altogether, our results reveal that the nucleo-cytoplasmic trafficking of the TLC1 RNA is an important step in telomere homeostasis, and link telomerase biogenesis to its recruitment to telomeres.     

A Multilevel Probabilistic Beam Search Algorithm for the Shortest Common Supersequence Problem

The shortest common supersequence problem is a classical problem with many applications in different fields such as planning, Artificial Intelligence and especially in Bioinformatics. Due to its NP-hardness, we can not expect to efficiently solve this problem using conventional exact techniques. This paper presents a heuristic to tackle this problem based on the use at different levels of a probabilistic variant of a classical heuristic known as Beam Search. The proposed algorithm is empirically analysed and compared to current approaches in the literature. Experiments show that it provides better quality solutions in a reasonable time for medium and large instances of the problem. For very large instances, our heuristic also provides better solutions, but required execution times may increase considerably.