Cranial morphological scaling and relative prey size limitations for a native predator in an invaded system

Over evolutionary time, predator-prey interactions have shaped and constrained functional and behavioral traits of piscivorous fishes. The endangered Colorado Pikeminnow Ptychocheilus lucius, a large endemic piscivore of the Colorado River Basin, encounters a substantially altered prey base that differs in behaviors and morphologies compared to the historical suite of native prey. To assess physical limitations of Colorado Pikeminnow predation, we conducted a feeding experiment with two species of nonnative prey (spined and despined Channel Catfish Ictalurus punctatus and Red Shiner Cyprinella lutrensis) and quantified scaling of cranial morphology in this predator. In our predation experiments, Colorado Pikeminnow (215–312 mm total length) consumed both spined and despined Channel Catfish as well as Red Shiner but only consumed prey less than 20% of the predator’s total length. Previous feeding trials using smaller Colorado Pikeminnow, with native and nonnative prey species, indicated they consumed prey up to 35% of their total length, suggesting relative prey size limits may decrease as this predator grows. Morphological measurements also suggested relative prey size suitability may decrease as Colorado Pikeminnow become larger, with head depth and width demonstrating isometric scaling at small sizes and shifting to negative allometry as fish get larger. Together, these data suggest an ontogenetic shift in the head morphology of Colorado Pikeminnow may decrease the relative size of prey available to these predators. In severely altered systems, understanding trophic characteristics that limit overall predator resource availability will be critical for conservation of piscivorous fishes.     

A cascade synthesis, in vitro cholinesterases inhibitory activity and docking studies of novel Tacrine-pyranopyrazole derivatives

In this work, we describe the preparation of some new Tacrine analogues modified with a pyranopyrazole moiety. A one-pot multicomponent reaction of 3-methyl-1H-pyrazol-5(4H)-one, aryl(or hetero)aldehydes, malononitrile and cyclohexanone involving a Friedländer condensation led to the title compounds. The synthesized heterocyclic analogues of this molecule were evaluated in vitro for their AChE and BChE inhibitory activities in search for potent cholinesterase enzyme inhibitors. Most of the synthesized compounds displayed remarkable AChE inhibitory activities with IC₅₀ values ranging from 0.044 to 5.80?µM, wherein compounds 5e and 5j were found to be most active inhibitors against AChE with IC₅₀ values of 0.058 and 0.044?µM respectively. Molecular modeling simulation on AChE and BChE receptors, showed good correlation between IC₅₀ values and binding interaction template of the most active inhibitors docked into the active site of their relevant enzymes.     

Development of a UHPLC-FLD method for the analysis of ergot alkaloids and application to different types of cereals from Luxembourg

Ergot alkaloids are toxins produced by some species of fungi in the genus Claviceps, that may infect rye and triticale and, in a minor degree, other types of cereals. In this study, a new UHPLC-FLD method for the quantification of the six major ergot alkaloids as well as their corresponding epimers was developed. The sample preparation was done by a solid-liquid extraction with acetonitrile and clean-up via freeze-out. The method was fully validated and then applied to 39 samples (wheat, rye, triticale, and barley) harvested in Luxembourg in 2016. Samples were sieved (1.9?×?20 mm) prior to analysis in order to remove sclerotia, hosting the alkaloids. However, 23 samples still contained at least one ergot alkaloid >?LOQ and concentrations of the sum of the 6 ergot alkaloids ranged from 0.3 to 2530.1 μg/kg. Interestingly, the highest concentrations were measured in wheat and not in rye or triticale, suggesting that all kinds of cereals should be included in monitoring programs. The outcome of this study allowed giving a first overview of ergot alkaloid concentrations in cereals harvested in Luxembourg, and the measured concentrations were in similar ranges than in other parts of the world (e.g., Canada, France, Germany).     

Agriculture shapes the trophic niche of a bat preying on multiple pest arthropods across Europe: Evidence from DNA metabarcoding

The interaction between agricultural production and wildlife can shape, and even condition, the functioning of both systems. In this study, we i) explored the degree to which a widespread European bat, namely the common bent‐wing bat Miniopterus schreibersii, consumes crop‐damaging insects at a continental scale, and ii) tested whether its dietary niche is shaped by the extension and type of agricultural fields. We employed a dual‐primer DNA metabarcoding approach to characterize arthropod 16S and COI DNA sequences within bat faecal pellets collected across 16 Southern European localities, to first characterize the bat species’ dietary niche, second measure the incidence of agricultural pests across their ranges and third assess whether geographical dietary variation responds to climatic, landscape diversity, agriculture type and vegetation productivity factors. We detected 12 arthropod orders, among which lepidopterans were predominant. We identified >200 species, 44 of which are known to cause agricultural damage. Pest species were detected at all but one sampling site and in 94% of the analysed samples. Furthermore, the dietary diversity of M. schreibersii exhibited a negative linear relation with the area of intensive agricultural fields, thus suggesting crops restrict the dietary niche of bats to prey taxa associated with agricultural production within their foraging range. Overall, our results imply that M. schreibersii might be a valuable asset for biological pest suppression in a variety of agricultural productions and highlight the dynamic interplay between wildlife and agricultural systems.     

Sex‐dependent thermal history influences cold tolerance,longevity and fecundity in false codling moth Thaumatotibia leucotreta (Lepidoptera: Tortricidae)

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A new cell surface proteinase: sequencing and analysis of the prtB gene from Lactobacillus delbruekii subsp. bulgaricus.

Investigation of the chromosomal region downstream of the lacZ gene from Lactobacillus delbrueckii subsp. bulgaricus revealed the presence of a gene (prtB) encoding a proteinase of 1,946 residues with a predicted molecular mass of 212 kDa. The deduced amino acid sequence showed that PrtB proteinase displays significant homology with the N termini and catalytic domains of lactococcal PrtP cell surface proteinases and is probably synthesized as a preproprotein. However, the presence of a cysteine near the histidine of the PrtB active site suggests that PrtB belongs to the subfamily of cysteine subtilisins. The C-terminal region strongly differs from those of PrtP proteinases by having a high lysine content, an imperfect duplication of 41 residues, and a degenerated sequence compared with the consensus sequence for proteins anchoring in the cell walls of gram-positive bacteria. Finally, the product of the truncated prtM-like gene located immediately upstream of the prtB gene seems too short to be involved in the maturation of PrtB.     

Spatial variation in selection in a plant-pollinator system in the wadis of Sinai,Egypt

We studied an insect-plant pollination system in adjacent steep-sided wadis and a connecting plain in the mountains of southern Sinai (Egypt): this environment creates a strongly divided habitat, which may promote the local differentiation of sub-populations. We tested for spatial differences in phenotypic reproductive characters of the only plant flowering abundantly in early spring, Alkanna orientalis (Boraginaceae), and its major pollinator at that time of year, Anthophora pauperata (Apoidea, Anthophoridae). There were significant morphological differences between sub-populations of Alkanna, mainly between plants from the narrower wadis and those on the interconnecting plain. Flowers on the plain were larger, with wider corollas and more nectar standing crop; these plants retained more flowers on the inflorescence, but received many fewer visits to flowers. There was a significant selection gradient between flower size and maternal fitness (seed set) in the plain, but not elsewhere. Natural selection may have increased resources devoted to attracting insect visitors in response to fewer pollinating visits in the plain. Consistent with this explanation, by experimentally manipulating flower number per plant, we showed that within a wadi having more flowers on a plant secured more visits.     

87Sr/86Sr Chronostratigraphy and dolomitization history of the Seroe Domi Formation,Curaçao (Netherlands Antilles)

Summary The Seroe Domi Formation is a 350 m-thick sequence of Neogene marine limestones and silicilastic sandstones cropping out on the leeward coast of Cura?ao, Netherlands Antilles. Integrated analyses of lithofacies, biostratigraphy, geochemistry and Sr isotope model age analyses indicate that Seroe Domi Formation has experienced three major episodes of limestone diagenesis and dolomitization (Dolomites I, I′, and II) that have taken place after successive Mio-Plio-Pleistocene depositional and subaerial exposure events (Subunits 1, 2, and 3). Subunit 1, the lowermost 30 to 100 m of the Seroe Domi Formation, is composed of interbedded coralgal grainstone gravity flows, pelagic wackestones, and allochthonous blocks deposited in Middle Miocene deep-water (>500 m) fore-reef and carbonate slope environments. Subunit 2, the uppermost 250 m of the Seroe Domi Formation, consists of coralgal packstones with basement-derived siliciclastic sands that were deposted in shallowing fore-reef to reef-front environments during the Late Miocene to Pliocene. Subunit 3 siliciclastic sandstones were deposited during the Early Pleistocene within erosional cavities in the Subunit 2 limestones, and are overlain by Late Pleistocene Quaternary Limestone Terraces. The petrography, distribution and geochemistry of Dolomites I, I′ and II indicate that they were precipitated from seawater-freshwater mixing zone fluid environments. Dolomite rhombs and meteoric calcite cements within biomolds illustrate that the host Seroe Domi Formation limestones were subaerially exposed prior to each dolomitization event. Dolomite I (δ¹⁸O = +1.04 to +2.46% PDB; δ¹³C = −2.55 to −6.79 PDB;⁸⁷Sr/⁸⁶Sr=0.708866 to 0.708915; Zn=0 ppm; Cu=0 ppm) was precipitated from mixtures of seawater with isotopically-depleted freshwater during the late Middle Miocene. Dolomite I′ (δ¹⁸O = +2.08 to +3.55 PDB, δ¹³C = −1.53 to 1.69 PDB,⁸⁷Sr/⁸⁶Sr=0.708981−0.709030; Zn=0 ppm; Cu=0 ppm) was also precipitated from mixtures of seawater with isotopically-depleted freshwater, but during late Late Miocene. In contrast, Dolomite II (δ¹⁸O = +2.69 to +3.51 PDB; δ¹³C = −0.34 to +1.53 PDB;⁸⁷Sr/⁸⁶Sr=0.708954 to 0.709088; Zn=20 ppm; Cu=20 ppm) precipitated from late Early Pliocene mixtures of seawater with isotopically-depleted freshwater that had derived Zn, Cu, and less-radiogenic Sr from basalts comprising the Cura?ao basement.