Metabolome and water status phenotyping of Arabidopsis under abiotic stress cues reveals new insight into ESK1 function

Metabolomic investigation of the freezing-tolerant Arabidopsis mutant esk1 revealed large alterations in polar metabolite content in roots and shoots. Stress metabolic markers were found to be among the most significant metabolic markers associated with the mutation, but also compounds related to growth regulation or nutrition. The metabolic phenotype of esk1 was also compared to that of wild type (WT) under various environmental constraints, namely cold, salinity and dehydration. The mutant was shown to express constitutively a subset of metabolic responses which fits with the core of stress metabolic responses in the WT. But remarkably, the most specific metabolic responses to cold acclimation were not phenocopied by esk1 mutation and remained fully inducible in the mutant at low temperature. Under salt stress, esk1 accumulated lower amounts of Na⁺ in leaves than the WT, and under dehydration stress its metabolic profile and osmotic potential were only slightly impacted. These phenotypes are consistent with the hypothesis of an altered water status in esk1 , which actually exhibited basic lower water content (WC) and transpiration rate (TR) than the WT. Taken together, the results suggest that ESK1 does not function as a specific cold acclimation gene, but could rather be involved in water homeostasis.     

The mitochondrial and nuclear genetic structure of Myotis capaccinii (Chiroptera: Vespertilionidae) in the Eurasian transition, and its taxonomic implications

Allopatric isolation in glacial refugia has caused differentiation and speciation in many taxa globally. In this study, we investigated the nuclear and mitochondrial genetic differentiation of the long fingered bat, Myotis capaccinii during the ice ages in south-eastern Europe and Anatolia. The mitochondrial DNA (mtDNA) analyses indicated a suture zone similar to those recorded in other animal species, including bats, suggesting the association of more than one refugium with the region. Contrary to most of the other species where a suture zone was seen in Anatolia, for M. capaccinii the geographical location of the genetic break was in south-eastern Europe. This mitochondrial differentiation was not reflected in the nuclear microsatellites, however, suggesting that the lack of contact during the ice ages did not result in reproductive isolation. Hence taxonomically, the two mitochondrial clades cannot be treated as separate species.     

The role of epiphytism in architecture and evolutionary constraint within mycorrhizal networks of tropical orchids

Characterizing the architecture of bipartite networks is increasingly used as a framework to study biotic interactions within their ecological context and to assess the extent to which evolutionary constraint shape them. Orchid mycorrhizal symbioses are particularly interesting as they are viewed as more beneficial for plants than for fungi, a situation expected to result in an asymmetry of biological constraint. This study addressed the architecture and phylogenetic constraint in these associations in tropical context. We identified a bipartite network including 73 orchid species and 95 taxonomic units of mycorrhizal fungi across the natural habitats of Reunion Island. Unlike some recent evidence for nestedness in mycorrhizal symbioses, we found a highly modular architecture that largely reflected an ecological barrier between epiphytic and terrestrial subnetworks. By testing for phylogenetic signal, the overall signal was stronger for both partners in the epiphytic subnetwork. Moreover, in the subnetwork of epiphytic angraecoid orchids, the signal in orchid phylogeny was stronger than the signal in fungal phylogeny. Epiphytic associations are therefore more conservative and may co‐evolve more than terrestrial ones. We suggest that such tighter phylogenetic specialization may have been driven by stressful life conditions in the epiphytic niches. In addition to paralleling recent insights into mycorrhizal networks, this study furthermore provides support for epiphytism as a major factor affecting ecological assemblage and evolutionary constraint in tropical mycorrhizal symbioses.     

An experimental and theoretical approach to the molecular structure of 2-{4-[3-(2,5-dimethylphenyl)-3-methylcyclobutyl]thiazol-2-yl}isoindoline-1,3-dione

The title compound, 2-{4-[3-(2,5-dimethylphenyl)-3-methylcyclobutyl]thiazol-2-yl}isoindoline-1,3-dione (C₂₄H₂₂N₂O₂S), was synthesized and characterized by IR-NMR spectroscopy and single-crystal X-ray diffraction. The compound crystallizes in the monoclinic space group P2₁/c with a?=?19.7799(13) Å, b?=?6.7473(4) Å, c?=?15.7259(9) Å and β?=?103.416(5)°. In addition, the molecular geometry, vibrational frequencies and gauge including atomic orbital (GIAO) ¹H and ¹³C chemical shift values of the title compound in the ground state have been calculated by using the Hartree-Fock (HF) and density functional method (DFT/B3LYP) with 6–31G(d), 6–31 + G(d,p) and LANL2DZ basis sets, and compared with the experimental data. To determine conformational flexibility, molecular energy profile of the title compound was obtained by semi-empirical (AM1) calculations with respect to two selected degrees of torsional freedom, which were varied from ?180° to +180° in steps of 5°. Besides, molecular electrostatic potential, frontier molecular orbitals (FMO) analysis and thermodynamic properties of the title compound were investigated by theoretical calculations.     

Diagnosing the environmental causes of the decline in Grey Partridge Perdix perdix survival in France

We studied Grey Partridge Perdix perdix mortality during breeding to identify the environmental causes of a long‐term decline in adult survival. We radiotagged and monitored daily from mid‐March to mid‐September 1009 females on ten contrasting study sites in 1995‐97. Simultaneously, we recorded habitat features and estimated the abundance of Hen and Marsh Harriers Circus cyaneus and C. aeruginosus Red Fox Vulpes vulpes and mustelids. We experimentally tested whether scavenging could have biased predation rates. We also examined, through the necropsy of 80 carcasses of Grey Partridge, whether disease, parasites or poisoning could have been ultimate causes of high predation rates. The survival rate of radiotagged females during spring and summer ranged from 0.25 to 0.65 across study areas. Mortality peaked in May, June and July when females were laying and incubating. The direct negative impact of farming practices was low (6%). Predation was the main proximate cause of female mortality during breeding (73%) and determined the survival rate, suggesting no compensation by other causes of mortality. Ground carnivores were responsible for 64% of predation cases, and raptors for 29%, but this proportion varied across study sites. Disease and poisoning did not appear to favour predation, and scavenging was not likely to have substantially overestimated predation rates. The predation rate on breeding females was positively correlated with the abundance of Hen and Marsh Harriers, suggesting an additional mortality in areas where harriers were abundant. The proportion of raptor predation was linearly related to harrier abundance. The predation rate was not correlated with the abundance of the Red Fox and mustelids. A potential density‐dependent effect on the predation rate was confounded by the abundance of harriers. We found no convincing relationship between the predation rate and habitat features, but we observed a positive relationship between the abundance of Hen and Marsh Harriers and the mean field size. This suggested that habitat characteristics may contribute to high predation rates through predator abundance or habitat‐dependent predation.     

Characterization of polymorphic microsatellite markers for the endangered Malagasy radiated tortoise (Geochelone radiata)

The radiated tortoise (Geochelone radiata) is an endangered endemic species from Madagascar that inhabits the semiarid spiny forest of the southern part of the island. Habitat destruction and illegal harvesting greatly threaten this species, as attested by the significant reduction of its distribution area in the past 30 years. In order to undertake appropriate conservation actions, it is essential to acquire a better knowledge of its genetic structure. For this study, 145 blood samples were collected from three populations of radiated tortoises in southwestern Madagascar. Eight microsatellite loci were found to be polymorphic, and allelic diversity and observed heterozygosity were high for all markers.     

Diversity and metabolic potential of culturable bacteria from the rhizosphere of Turkish tea grown in acidic soils

The purpose of this study was to investigate the diversity of cultivable phosphate solubilising (PSB) and total bacteria originated from 384 rhizospheric acidic soils samples of tea plants grown at 32 locations. Over 900 rhizoplane bacteria were randomly selected from agar-solidified trypticase soy broth, and identified using fatty acid methyl ester (FAME) profiles. Based on FAME profiles, 53 bacterial genera were identified with a similarity index >0.3, but 60.3% of the identified isolates belonged to five genera: Bacillus (34.6%), Pseudomonas (8.9%), Stenotrophomonas (6.1%), Paenibacillus (5.9%) and Arthrobacter (4.8%). The bacilli group comprised many different species, with the most abundant being B. cereus, B. megaterium and B. sphaericus. The main identified Pseudomonads included P. fluorescens, P. putida, and P. alcaligenes. About 30.4% of the bacterial isolates could not be classified to genus since their similarity indices were <0.3 indicating no close matches. Most of the total and P-solubilizing bacteria isolated were Gram positive (61.3 and 52.3%), and Gram negative constituted only 38.7 and 47.7%. Out of the 214 PSB from a pool of 506 bacterial isolates recovered on the selective media from the rhizosphere of tea, 74 of them were characterized by carbon sources using BIOLOG^M GN2 and GP2 plates. Bacillus, Pseudomonas, Paenibacillus and Stenotrophomonas genera were the most prominent P-solubilizing groups in the rhizosphere and soil populations analyzed. B. cereus, P. fluorescens, S. maltophilia, B. megaterium, P. putida, B. sphaericus and Paenibacillus polymyxa were the most frequent P-solubilizing species in the acidic tea rhizosohere soils. Selected Gram-positive PSB appeared to favour carbohydrates, and Gram-negative bacteria appeared to favour carboxylic acids, amino acids and carbohydrates as carbon sources. Selected phosphate solubilizing acid tolerant strains showed high variability in utilizing various carbon sources.     

Insights into the adaptive significance of vertical pupil shape in snakes

Pupil shape in vertebrates ranges from circular to vertical, with multiple phylogenetic shifts in this trait. Our analyses challenge the widely held view that the vertical pupil evolved as an adaptation to enhance night vision. On functional grounds, a variable‐aperture vertical pupil (i) allows a nocturnal species to have a sensitive retina for night vision but avoid dazzle by day by adjusting pupil closure, and (ii) increases visual acuity by day, because a narrow vertical pupil can project a sharper image onto the retina in the horizontal plane. Detection of horizontal movement may be critical for predators that wait in ambush for moving prey, suggesting that foraging mode (ambush predation) as well as polyphasic activity may favour the evolution of vertical pupil shape. Camouflage (disruption of the circular outline of the eye) also may be beneficial for ambush predators. A comparative analysis in snakes reveals significant functional links between pupil shape and foraging mode, as well as between pupil shape and diel timing of activity. Similar associations between ambush predation and vertically slit pupils occur in lizards and mammals also, suggesting that foraging mode has exerted major selective forces on visual systems in vertebrates.     

Development of Vaccine Prototype Against Zika Virus Disease of Peptide-Loaded PLGA Nanoparticles and Evaluation of Cytotoxicity

Zika virus has recently evolved from an obscure mosquito-borne pathogen to an international public health concern. People with Zika virus disease can have indications including mild fever, skin rash, conjunctivitis, muscle pain, malaise or headache. Effective vaccines are needed for controlling and preventing the disease. In the current study, we aim to design the substructure for vaccine against Zika virus by forming antigenic peptide epitope of the disease. Zika peptide loaded poly (lactic-co-glycolic acid) (PLGA) nanoparticles have been fabricated in the present work as a potential artificial vaccine. UV and FT-IR Spectrophotometers and ZetaSizer were used for studying the nanoparticles, and Scanning Electron Microscope was used for morphological examination. The nanoparticles (NPs) yield, encapsulation efficiency, the peptide loading capacity were determined and in vitro release of the peptide was studied. Cytotoxic effects of the various concentrations of Zika peptide, blank PLGA nanoparticles and Zika peptide loaded PLGA nanoparticles on ECV304 human epithelial cells were determined via MTT assay. The present paper could be considered as one of the important steps in the use of nanoparticles for constructing the new generation of vaccination systems.