Ulteriori osservazioni ed esperienze sulla monoginia dei Formicidi: Saggio di un'analisi del comportamento inLeptothorax exilis Em.

Riassunto L'autore riassume le attuali conoscenze sulla monoginia dei formicidi e discute dell'opportunità di adottare questo termine in luogo di altri preesistenti nella letteratura. Vengono inoltre riferite alcune esperienze in base alle quali è lecito concludere che ilLeptothorax exilis Em. è specie monogina e che questa condizione, nel caso di fusione tra colonie giovani, è assicurata dall'intervento delle operaie. L'aggressività delle operaie nei confronti delle regine estranee non può essere spiegata solo in base alla diversità dell'odore caratteristico del formicaio ed è in stretta correlazione con la presenza della regina madre od anche solo del suo cadavere. Vengono inoltre schematizzati i diversi metodi con cui le formiche si assicurano la monoginia della colonia.

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Summary The autor summarizes present knowledge about the monogyny of Formicidae and considers the appropriateness of this term in preference to those hitherto in use. The A. also reports some experiences that lead to the conclusion thatLeptothorax exilis Em. is a monogynic species, a condition which in case of the fusion of young colonies is assured by the intervention of the workers. The aggressive behaviour of the workers toward foreign queens cannot be explained solely by the diversity of the odor characteristic of each colony. It is also in direct relationship with the presence of the queen mother or even just her corpse. The A. outlines the various methods by which ants assure the monogyny of the colony.

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Résumé L'auteur résume les connaissances actuelles sur la monogynie des fourmis et discute l'opportunité d'adopter ce terme au lieu des autres préexistants dans la littérature. Il rapporte en outre quelques expériences qui lui permettent de conclure queLeptothorax exilis Em. est une espèce monogyne et que cette condition, en cas de fusion entre jeunes colonies, est assurée par l'intervention des ouvrières. L'hostilité des ouvrières contre les reines étrangères ne peut pas être expliquée par la seule diversité de l'odeur caractéristique du nid et est strictement liée à la présence de la reine mère ou même seulement à celle de morceaux de son cadavre. On fournit enfin un schéma des différentes méthodes avec lesquelles les fourmis assurent la monogynie de la colonie.

     

Interaction of alpha-sarcin and gelonin with Cibacron blue

Alpha-sarcin and gelonin, two proteins which inactivate the 60S ribosomal subunit, interact with Cibacron blue and bind to blue dextran-Sepharose, from which they are partially desorbed by nucleoside triphosphates and, more efficiently, by homopolynucleotides. It is further shown that the two proteins bind to poly(U)-Sepharose and that homopolynucleotides protect dilute solutions of both inhibitors from inactivation. It is suggested that the presence of a polynucleotide site on alphasarcin is related to its ribonuclease activity. The existence of a similar site on gelonin might be a clue to its yet unknown mechanism of action.     

Study of fumarase activity in non-conventional media. Part I

Fumarase catalysed hydration of fumarate was investigated in water/organic solvent one-phase systems. The organic solvents used were ethylene glycol, glycerol and dimethylformamide. The effects of the amount of organic solvent on the maximum velocity (V_max), the Michaelis-Menten constant (K_M) and the equilibrium constant (K_eq) were studied in all the reaction media. Together with a denaturing power of the solvent evidenced by a systematic decrease of V_max also a surprising decrease of the K_M was registered as the percentage of organic solvent in the reaction media was increased. While the equilibrium constant of the reaction (K_eq = [l-malate]/[fumarate]) decreased when the percentage of organic solvent was raised. An interpretation of these facts was given. Time-dependent denaturation was also investigated and glycerol resulted the less denaturing of the solvents used, while the aprotic DMF exhibited the highest deactivation.     

Heme-peptide/protein ions and phosphorous ligands: search for site-specific addition reactions

High-resolution Fourier transform ion cyclotron resonance mass spectrometry is employed to gain thorough kinetics and thermodynamics information on the reaction of free and ligated heme-type ions with selected ligands, with the aim of obtaining an insight into the coordination environment of the prosthetic group in a variety of biomolecular ions. Adopting a stepwise approach towards systems of increasing complexity, we examined the reactivity of free gaseous iron(III) protoporphyrin IX ions, Fe(III)-heme(+), of the charged species from microperoxidase-11 (MP11) (covalently peptide bound heme), and of the multiply charged ions from heme proteins, namely, cytochrome c (cyt c) and myoglobin (examples of noncovalently protein bound hemes). Among an array of test compounds allowed to react with Fe(III)-heme(+), OP(OMe)(3) and P(OMe)(3) proved to be similarly efficient ligands in the first addition step, yet displayed markedly distinct reactivity towards heme iron already engaged in axial coordination. The ease with which P(OMe)(3) acts as a second axial ligand is exploited to probe structural and conformational features of biomolecular ions. In this way, circumstantial evidence is gained of a folded conformation of +2 charge state ions from MP11 and an elongated one for the +3 charge state ions. Similarly, both the general reaction pattern and detailed kinetics and thermodynamics data point to a regiospecific addition reaction of P(OMe)(3) directed at the heme iron within multiply charged ions from cyt c. This unprecedented example of ion-molecule reaction which specifically involves a prosthetic group belonging to protein ions stands in contrast to the multiple, nonspecific interactions established by OP(OMe)(3) molecules with the protonated sites of multiply charged cyt c and apomyoglobin ions. This finding may develop and provide sensitive probes of the structure and bonding features of protein ions in the gas phase.     

Chemical Characterization of Different Extracts from Artemisia annua and Their Antioxidant,Enzyme Inhibitory and Anti-Inflammatory Properties

Artemisia annua L. (Asteraceae Family) is an important plant in Asia that has been used for treating different diseases, including fever due to malaria, wounds, tubercolisis, scabues, pain, convulsions, diabetes, and inflammation. In this study we aimed to evaluate the effects of different polarity extracts (hexane, dichloromethane, ethyl acetate, ethanol, ethanol/water (70 %) and water) from A. annua against the burden of inflammation and oxidative stress occurring in colon tissue exposed to LPS. In parallel, chemical composition, antiradical, and enzyme inhibition effects against α-amylase, α-glucosidase, tyrosinase, and cholinesterases were evaluated. The water extract contained the highest content of the total phenolic with 34.59 mg gallic acid equivalent (GAE)/g extract, while the hexane had the highest content of the total flavonoid (20.06 mg rutin equivalent (RE)/g extract). In antioxidant assays, the polar extracts (ethanol, ethanol/water and water) exhibited stronger radical scavenging and reducing power abilities when compared to non-polar extracts. The hexane extract showed the best AChE, tyrosinase and glucosidase inhibitory effects. All extracts revealed effective anti-inflammatory agents, as demonstrated by the blunting effects on COX-2 and TNFα gene expression. These effects seemed to be not related to the only phenolic content. However, it is worthy of interest to highlight how the higher potency against LPS-induced gene expression was shown by the water extract ; thus suggesting a potential phytotherapy application in the management of clinical symptoms related to inflammatory colon diseases, although future in vivo studies are needed to confirm such in vitro and ex vivo observations.     

Ploidy levels and reproductive behaviour in natural populations of five Paspalum species

Knowledge of variation in ploidy levels and reproductive behaviour in natural populations is essential in order to understand the functioning of agamic complexes. The aim of this study was to analyse the ploidy level and mode of reproduction in several wild Paspalum populations. A total of 19 populations representing five different species (P. alcalinum, P. denticulatum, P. lividum, P. nicorae, and P. rufum) were collected. Ploidy level was determined in 1,187 individuals by using flow cytometry. Among these individuals, 2x, 3x, 4x, 5x, 6x, and 7x chromosome constitutions were observed. Diploid sexual cytotypes of P. denticulatum were detected for the first time; this will allow the development of future breeding strategies for this particular species. Flow cytometry seed screen (FCSS) in bulked and single seeds revealed the reproductive diversity of these species, ranging from complete sexuality in diploids and varying levels of facultative apomixis in most tetraploids, to obligate apomixis in pentaploids and hexaploids. A fully sexual tetraploid plant was never detected. Nevertheless, most tetraploid genotypes produced both maternal (by apomixis) and non-maternal (by sexuality) progeny. This residual sexuality is very interesting from an evolutionary point of view, since it would allow the creation of new genotypic combinations in natural populations. In addition, the residual sexuality found in some apomictic tetraploid populations can be used as a source of variability for genetic improvement.     

Detecting Large Germline Rearrangements of BRCA1 by Next Generation Tumor Sequencing

Molecular Biology - A majority of BRCA1/2 (BRCA) pathogenic variants (PVs) are single nucleotide substitutions or small insertions/deletions. Copy number variations (CNVs), also known as large...