Mechanisms of group-hunting in vertebrates

Group-hunting is ubiquitous across animal taxa and has received considerable attention in the context of its functions. By contrast much less is known about the mechanisms by which grouping predators hunt their prey. This is primarily due to a lack of experimental manipulation alongside logistical difficulties quantifying the behaviour of multiple predators at high spatiotemporal resolution as they search, select, and capture wild prey. However, the use of new remote-sensing technologies and a broadening of the focal taxa beyond apex predators provides researchers with a great opportunity to discern accurately how multiple predators hunt together and not just whether doing so provides hunters with a per capita benefit. We incorporate many ideas from collective behaviour and locomotion throughout this review to make testable predictions for future researchers and pay particular attention to the role that computer simulation can play in a feedback loop with empirical data collection. Our review of the literature showed that the breadth of predator:prey size ratios among the taxa that can be considered to hunt as a group is very large (<10⁰ to >10²). We therefore synthesised the literature with respect to these predator:prey ratios and found that they promoted different hunting mechanisms. Additionally, these different hunting mechanisms are also related to particular stages of the hunt (search, selection, capture) and thus we structure our review in accordance with these two factors (stage of the hunt and predator:prey size ratio). We identify several novel group-hunting mechanisms which are largely untested, particularly under field conditions, and we also highlight a range of potential study organisms that are amenable to experimental testing of these mechanisms in connection with tracking technology. We believe that a combination of new hypotheses, study systems and methodological approaches should help push the field of group-hunting in new directions.     

The modeling of interactions of the CYP2E1 isoform of human cytochrome P450 with substrates

The interactions between the substrates of the 2E1 isoform of the human cytochrome P450 and receptor were simulated. It was found that the CP4 isoform of the cytochrome of the bacterial cell is highly homologous to the 2E1 isoform of the human cytochrome P450. The orientation of the substrates of the 2E1 isoform in the CP4 isoform of the bacterial cell cytochrome was performed. A cavity in the receptor was found that is responsible for the binding of the substrate. Amino acid residues Phe87, Pro89, Val119, Thr185, Leu244, Leu245, Leu246, Val247, Gly248, Gly249, Thr252, Val295, Asp297, Cys357, Ile395, and Val396, the heme, and water molecules are involved in the formation of the cavity. The mode of the interactions of the substrate molecule with cytochrome was analyzed. Active sites of the receptor, and a part of the substrate molecule responsible for the binding to cytochrome were found. Equations for the dependence of the Michaelis constant on the structural parameters of complexes of substrates with cytochrome were derived.     

Comparative characteristics of the metabolism of E. coli cells with various activity of penicillin acylase

A correlation between the synthesis and secretion of penicillin acylase (PA; EC 3.5.1.11) and the membrane phospholipid composition was observed in three E. coli strains. In cells with overproduction of PA, the phospholipid/protein ratio decreases, while the cardiolipin/phosphatidylglycerol ratio increases. The differences in the functioning of the electron transport system were revealed in cells with different levels of PA synthesis and secretion. The O2 consumption rate was 3 times lower in the cells with overproduction of PA than in those of less productive strains. On the contrary, membrane particles isolated from the cells of PA producers had no significant differences in the O2-reduction rate. The sensitivity of the strains to the inhibitor of terminal oxidases, sodium cyanide, and to the uncoupler of redox phosphorylation, chlorocarbonyl-phenylhydrazone, was different. Thus the E. coli cells with PA overproduction are characterized by significant changes in energetics and constructive metabolism. The interrelations between PA overproduction, phospholipid metabolism and the respiratory chain activity are discussed.     

Larvae of related Diptera species from thermally contrasting habitats exhibit continuous up-regulation of heat shock proteins and high thermotolerance

A population of Stratiomys japonica, a species belonging to the family Stratiomyidae (Diptera), common name ‘soldier flies’, occurs in a hot volcanic spring, which is apparently among the most inhospitable environments for animals because of chemical and thermal conditions. Larvae of this species, which naturally often experience temperatures more than 40 °C, have constitutively high concentrations of the normally inducible heat-shock protein Hsp70, but very low level of corresponding mRNA. Larvae of three other species of the same family, Stratiomys singularior, Nemotelus bipunctatus and Oxycera pardalina, are confined to different type semi-aquatic habitats with contrasting thermal regime. However, all of them shared the same pattern of Hsp70 expression. Interestingly, heat-shock treatment of S. japonica larvae activates heat-shock factor and significantly induces Hsp70 synthesis, whereas larvae of O. pardalina, a species from constant cold environment, produce significantly less Hsp70 in response to heat shock. Adults of the four species also exhibit lower, but detectable levels of Hsp70 without heat shock. Larvae of all species studied have very high tolerance to temperature stress in comparison with other Diptera species investigated, probably representing an inherent adaptive feature of all Stratiomyidae enabling successful colonization of highly variable and extreme habitats.     

Molecular phylogeny of fungus gnats (Diptera: Mycetophilidae) revisited: position of Manotinae,Metanepsiini, and other enigmatic taxa as inferred from multigene analysis

The phylogeny of selected genera from four subfamilies of fungus gnats (Diptera: Mycetophilidae) – Manotinae, Leiinae, Sciophilinae and Gnoristinae (including Metanepsiini) – is reconstructed based on the combined analysis of five mitochondrial (12S, 16S, COI, COII, cytB) and two nuclear (28S, ITS2) gene markers. Results of the different analyses all support Manotinae as a monophyletic group, with Leiinae as the sister group. Allactoneura DeMeijere is nested in the monophyletic and strongly supported clade of Leiinae. The tribe Metanepsiini is revealed as paraphyletic and the genera Metanepsia Edwards and Chalastonepsia Søli do not appear to be closely related. The genera Docosia Winnertz, Ectrepesthoneura Enderlein, Novakia Strobl and Syntemna Winnertz were placed with a group of genera included traditionally in the Gnoristinae. The monophyly of Dziedzickia Johannsen and Phthinia Winnertz is not supported. The genera of Sciophilinae (excluding Paratinia Mik but including Eudicrana Loew) form a monophyletic group in the Bayesian model.