Insect ecology and veteran trees

Insect and veteran trees are important parts of ecosystems and are usually included in ecological studies of forest management. The loss of veteran trees in woodlands and open landscapes would lead to the loss of saproxylic organisms—an important part of biodiversity. Hence, the persistence of many specialized insects depends on the presence of veteran trees scattered in woodlands (e.g. ancient wood pastures, game parks or protected areas), cities, towns and villages (e.g. avenues, parks or chateau parks) or open landscapes (e.g. fishpond dams, solitary trees or fruit orchards). Veteran tree conditions could be fairly well described by three components—diameter, age and microhabitats present. The problem is that diameter belongs to the most studied characteristics, while age and microhabitats, which can be quite complicated to measure, are much less studied. This paper illustrates that, due to this unbalanced use of indicators of veteran-tree conditions, we are still missing some important information on saproxylic species ecology—and sometimes only large trees might be studied, rather than real veterans. Although we already know that veteran trees are essential habitat for a range of saproxylic organisms, there are still gaps in our knowledge of the specific conditions that veteran trees provide. It is vital that these are quantified and understood so that this information can be used to conserve veteran trees and their associated species.     

Ostracism of an Albino Individual by a Group of Pigmented Catfish

Physiological and behavioural constraints hinder albino individuals. Albino animals are rare in the wild; this trait is associated with easy detection by predators, non-native or damaged environments, and exclusively aphotic environments in total darkness. The social aspect of albinism is reported only for human beings, and the effect is distinguishable in time and space when social benefits, are used to a limited the extent. Thus far, the social consequences of albinism for animals remain unknown. We used socially established groups of the pigmented catfish, (Silurus glanis), to observe space and temporal distance detachment of albino specimens in laboratory conditions. The albino fish were separated at larger distances from the group than pigmented individuals with the same social status determined by familiarity, and this asymmetry also varied in time. Albinism-related ostracism results in a solitary existence, usually followed by enhanced predation risk. The motivation for an individual’s exclusion from a group appears to be the avoidance of the predation risk that increases not only for an odd individual but also for conspecifics within a group. Our findings indicate a role for albinism in behavioural processes related to sociality in a group of conspecifics.     

Evidence for Na+/H+ antiport inMethanospirillum Hungatei

The growth and methane formation ofMethanospirillum hungatei were inhibited by an inhibitor of Na⁺/H⁺ antiport amiloride. After addition of NaCl or LiCl, when the cells had a lower intracellular pH and were deenergized, they extruded protons into the external medium. The acidification of the external medium was stimulated by protonophores and inhibited by amiloride. These findings suggest the existence of an Na⁺/H⁺ antiport in the cytoplasmic membrane ofM. hungatei and its role in the energetics of methanogenic bacteria.     

Synthesis,Molecular Modeling,and Biological Evaluation of Novel Chiral Thiosemicarbazone Derivatives as Potent Anticancer Agents

A series of new chiral thiosemicarbazones derived from homochiral amines in both enantiomeric forms were synthesized and evaluated for their in vitro antiproliferative activity against A549 (human alveolar adenocarcinoma), MCF‐7 (human breast adenocarcinoma), HeLa (human cervical adenocarcinoma), and HGC‐27 (human stomach carcinoma) cell lines. Some of compounds showed inhibitory activities on the growth of cancer cell lines. Especially, compound 17b exhibited the most potent activity (IC₅₀ 4.6 μM) against HGC‐27 as compared with the reference compound, sindaxel (IC₅₀ 10.3 μM), and could be used as a lead compound to search new chiral thiosemicarbazone derivatives as antiproliferative agents. Chirality 27:177–188, 2015. © 2014 Wiley Periodicals, Inc.     

The influence of different modifications of elongation factor Tu from Escherichia coli on ternary complex formation investigated by fluorescence spectroscopy.

A fluorescence titration assay was used to detect the effects of various modifications of E.coli elongation factor Tu on the formation of the ternary complex with aminoacyl-tRNAs. The treatment of EF-Tu.GDP with TPCK, an analogue of the 3'terminus of aminoacyl-tRNA, was found to have no influence on the conversion of EF-Tu.GDP to 'active' EF-Tu.GTP, but does decrease the affinity of the activated protein for yeast aminoacyl-tRNA by more than three orders of magnitude. Modification of the elongation factor by limited cleavage with trypsin, leading to the excision of amino acid residues 45-58, has only a minor influence on ternary complex formation. The equilibrium dissociation constant of the ternary complex with this trypsin-treated EF-Tu.GTP and E.coli Phe-tRNA(Phe) is only one order of magnitude higher than that of the ternary complex with native EF-Tu. Mutations in the amino acid residues 222 and 375 of EF-Tu also have little effect on ternary complex formation. Compared with TPCK-treated EF-Tu, the affinities of the two mutant species, designated EF-tuAR and EF-TuBO respectively, for [AEDANS-s2C]Tyr-tRNA(Tyr) are only slightly reduced and in the same range as trypsin-cleaved EF-Tu.