The effects of local and landscape-scale habitat characteristics and prey availability on corridor use by carnivores: A comparison of two contrasting farmlands

Corridors are thought to reduce the negative biological effects of habitat loss and fragmentation by providing connectivity and suitable habitat for many species, including carnivores. Although corridor structure maintenance is considered to be an essential tool for carnivore conservation in a human-dominated landscape, surprisingly little is known about the effects of different factors at various spatial scales. The main aim of this study was to determine how local and landscape-scale habitat characteristics and prey availability influence the corridor use by carnivores in a Central European agricultural landscape. Moreover we investigated carnivore corridor occurrence in two contrasting landscapes that differ in level of habitat loss and fragmentation to evaluate relative effect of species-specific response to regional context. Results show that the availability of principal prey (small mammals) was the most crucial factor affecting carnivore corridor use. Other important factors influencing corridor use were corridor width (positive), proportion of shrubs (positive) and presence of local, low-traffic, roads (positive). Single species models revealed interspecific and area-specific differences in carnivore preference at both spatial scales. Our findings confirm the general importance of multi-level approach to evaluating species-specific habitat requirements as a crucial tool for determining suitable methods for carnivore efficient conservation in human-dominated agricultural landscape.     

Classification of mitocans,anti-cancer drugs acting on mitochondria

Mitochondria have emerged as an intriguing target for anti-cancer drugs, inherent to vast majority if not all types of tumours. Drugs that target mitochondria and exert anti-cancer activity have become a focus of recent research due to their great clinical potential (which has not been harnessed thus far). The exceptional potential of mitochondria as a target for anti-cancer agents has been reinforced by the discouraging finding that even tumours of the same type from individual patients differ in a number of mutations. This is consistent with the idea of personalised therapy, an elusive goal at this stage, in line with the notion that tumours are unlikely to be treated by agents that target only a single gene or a single pathway. This endows mitochondria, an invariant target present in all tumours, with an exceptional momentum. This train of thoughts inspired us to define a class of anti-cancer drugs acting by way of mitochondrial ‘destabilisation’, termed ‘mitocans’. In this communication, we define mitocans (many of which have been known for a long time) and classify them into several classes based on their molecular mode of action. We chose the targets that are of major importance from the point of view of their role in mitochondrial destabilisation by small compounds, some of which are now trialled as anti-cancer agents. The classification starts with targets at the surface of mitochondria and ending up with those in the mitochondrial matrix. The purpose of this review is to present in a concise manner the classification of compounds that hold a considerable promise as potential anti-cancer drugs.     

How Much Is Our Fairness Worth? The Effect of Raising Stakes on Offers by Proposers and Minimum Acceptable Offers in Dictator and Ultimatum Games

Background

The aim of this study was to determine whether people respond differently to low and high stakes in Dictator and Ultimatum Games. We assumed that if we raised the stakes high enough, we would observe more self-orientated behavior because fairness would become too costly, in spite of a possible risk of a higher punishment.

Methods

A questionnaire was completed by a sample of 524 university students of biology. A mixed linear model was used to test the relation between the amount at stake (CZK 20, 200, 2,000, 20,000 and 200,000, i.e., approximately $1–$10,000) and the shares, as well as the subjects’ gender and the design of the study (single vs. multiple games for different amounts).

Results

We have discovered a significant relationship between the amount at stake and the minimum acceptable offer in the Ultimatum Game and the proposed shares in both Ultimatum and Dictator Games (p = 0.001, p<0.001, p = 0.0034). The difference between playing a single game or more games with several amounts at stake did not influence the relation between the stakes and the offered and minimum acceptable shares. Women proved significantly more generous than men in their offers in the Dictator Game (p = 0.007).

Conclusion

Our results suggest that people’s behavior in the Dictator and Ultimatum Games depends on the amount at stake. The players tended to lower their relative proposed shares, as well as their relative minimum acceptable offers. We propose that the Responders’ sense of equity and fair play depends on the stakes because of the costs of maintaining fairness. However, our results also suggest that the price of fairness is very high and that it is very difficult, probably even impossible, to buy the transition of Homo sociologicus into Homo economicus.     

Syntenic Relationships between the U and M Genomes of Aegilops,Wheat and the Model Species Brachypodium and Rice as Revealed by COS Markers

Diploid Aegilops umbellulata and Ae. comosa and their natural allotetraploid hybrids Ae. biuncialis and Ae. geniculata are important wild gene sources for wheat. With the aim of assisting in alien gene transfer, this study provides gene-based conserved orthologous set (COS) markers for the U and M genome chromosomes. Out of the 140 markers tested on a series of wheat-Aegilops chromosome introgression lines and flow-sorted subgenomic chromosome fractions, 100 were assigned to Aegilops chromosomes and six and seven duplications were identified in the U and M genomes, respectively. The marker-specific EST sequences were BLAST-ed to Brachypodium and rice genomic sequences to investigate macrosyntenic relationships between the U and M genomes of Aegilops, wheat and the model species. Five syntenic regions of Brachypodium identified genome rearrangements differentiating the U genome from the M genome and from the D genome of wheat. All of them seem to have evolved at the diploid level and to have been modified differentially in the polyploid species Ae. biuncialis and Ae. geniculata. A certain level of wheat–Aegilops homology was detected for group 1, 2, 3 and 5 chromosomes, while a clearly rearranged structure was showed for the group 4, 6 and 7 Aegilops chromosomes relative to wheat. The conserved orthologous set markers assigned to Aegilops chromosomes promise to accelerate gene introgression by facilitating the identification of alien chromatin. The syntenic relationships between the Aegilops species, wheat and model species will facilitate the targeted development of new markers specific for U and M genomic regions and will contribute to the understanding of molecular processes related to allopolyploidization.     

Comparative analysis of chromosome 2A molecular organization in diploid and hexaploid wheat

Molecular Biology Reports - Diploid A genome wheat species harbor immense genetic variability which has been targeted and proven useful in wheat improvement. Development and deployment of...     

Prdm9 Intersubspecific Interactions in Hybrid Male Sterility of House Mouse

The classical definition posits hybrid sterility as a phenomenon when two parental taxa each of which is fertile produce a hybrid that is sterile. The first hybrid sterility gene in vertebrates, Prdm9, coding for a histone methyltransferase, was identified in crosses between two laboratory mouse strains derived from Mus mus musculus and M. m. domesticus subspecies. The unique function of PRDM9 protein in the initiation of meiotic recombination led to the discovery of the basic molecular mechanism of hybrid sterility in laboratory crosses. However, the role of this protein as a component of reproductive barrier outside the laboratory model remained unclear. Here, we show that the Prdm9 allelic incompatibilities represent the primary cause of reduced fertility in intersubspecific hybrids between M. m. musculus and M. m. domesticus including 16 musculus and domesticus wild-derived strains. Disruption of fertility phenotypes correlated with the rate of failure of synapsis between homologous chromosomes in meiosis I and with early meiotic arrest. All phenotypes were restored to normal when the domesticus Prdm9^dom2 allele was substituted with the Prdm9^dom2H humanized variant. To conclude, our data show for the first time the male infertility of wild-derived musculus and domesticus subspecies F1 hybrids controlled by Prdm9 as the major hybrid sterility gene. The impairment of fertility surrogates, testes weight and sperm count, correlated with increasing difficulties of meiotic synapsis of homologous chromosomes and with meiotic arrest, which we suppose reflect the increasing asymmetry of PRDM9-dependent DNA double-strand breaks.     

Errors in egg-laying by female Common Cuckoo Cuculus canorus in nests of its common host

Dozens of studies have documented that brood parasites are well adapted to a brood parasitic lifestyle but not all parasitism events are successful. Co-evolution between brood parasites and their hosts is a dynamic process so it is reasonable to expect that a female brood parasite may commit errors during egg deposition by laying her eggs outside the laying period of the host, with consequent impacts on her fitness. Using an extensive dataset from a long-term study, we evaluated egg-laying patterns and errors related to the timing of egg-laying in the Common Cuckoo Cuculus canorus (hereafter ‘Cuckoo’). Specifically, we tested whether the Cuckoo avoids laying before or on the day of host clutch initiation to reduce the risk of rejection of parasitic eggs, whether laying errors will be more frequent in periods with a lack of active host nests, and whether the laying errors will be more frequent in periods with intense Cuckoo parasitism and a consequent lack of suitable host nests. We found that about one-third of Cuckoo eggs were laid on the host clutch initiation day or 1 day before, and the percentage of Cuckoo eggs laid decreased thereafter. Surprisingly, the probability of Cuckoo egg acceptance by the hosts was not affected by the egg-laying stage of the host clutch. Errors in the timing of egg-laying with fatal consequences (i.e. those precluding Cuckoo hatching because of laying in incubated or deserted clutches) were recorded in about 5% of cases. Only laying date of a Cuckoo egg had a significant effect on the probability of errors, which increased during the breeding season. This may be related to the higher number of deserted and incubated host nests at the site at the end of the breeding season. Errors in egg-laying may be attributed to young and inexperienced females but also impaired body condition or intraspecific competition may cause this behaviour. Future studies, which will test these possible explanations, will help to understand better the mechanism of co-evolutionary arms races and differences between host specialist and generalist brood parasites in various host–parasite systems.     

Effect of Subpressor Dose of Angiotensin II on Pain-Related Behavior in Relation with Neuronal Injury and Activation of Satellite Glial Cells in the Rat Dorsal Root Ganglia

To clarify the role of angiotensin II (Ang II) in the regulation of sensory signaling, we studied the effect of subpressor dose (150 ng/kg/min) of Ang II on pain-related behavior in relation with neuronal injury and activation of satellite glial cells (SGCs) in the dorsal root ganglia (DRGs) after chronic constriction injury (CCI). Systemic continuous delivery of Ang II induced the tactile, heat and cold hyperlagesia, when measured at 7 days ofpost-injury. Blockade of the AT₁ receptor with losartan (2.5 mg/kg/day) prevented tactile hyperalgesia and attenuated cold hyperalgesia, but did not affect the response to noxious heat stimulus. A marked increase of large-sized injured primary afferent neurons, detected by ATF3 immunolabeling, was seen in lower lumbar DRGs on ipsilateral side after Ang II treatment. Subpressor dose of Ang II induced an increase of activated SGCs (detected by GFAP immunolabeling) enveloping large-diameter neurons. Our results suggested that Ang II through the AT₁ receptor activation is an important regulatory factor in neuropathic pain perception and plays an important role in the injury of large-sized primary afferent neurons and activation of SGCs elicited by the CCI.     

Probing antioxidant activity of 2′-hydroxychalcones: Crystal and molecular structures, in vitro antiproliferative studies and in vivo effects on glucose regulation

In order to better understand the antioxidant behavior of a series of polyphenolic 2′-hydroxychalcones, we describe the results of several chemical and biological studies, in vitro and in vivo. Single crystal X-ray methods elucidated their molecular structures and important intermolecular interactions such as H-bonding and molecular stacking in the crystal structures that contribute to our knowledge in explaining antioxidant activity. The results of experiments using the 1,1-diphenyl-2-dipicrylhydrazyl (DPPH) UV–vis spectroscopic method indicate that a hydroxyl group in position 5′ induces the highest antioxidant activity. Consequently, 2,2′,5′-trihydroxychalcone was selected for further study in vitro towards ROS scavenging in L-6 myoblasts and THP-1 human monocytes, where it shows an excellent antioxidant activity in a concentration range lower than that reported by most studies of related molecules. In addition, this chalcone shows a very selective activity: it inhibits the proliferation of leukemic cells, but it does not affect the normal L-6 myoblasts and human fibroblasts. In studying 2,2′,5′-trihydroxychalcone's effect on weight gain and serum glucose and insulin levels in Zucker fatty (fa⁻/fa⁻) rats we found that supplementing the diet with a 10 mg/kg dose of this chalcone (3 times weekly) blunted the increase in glucose that co-occurs with weight gain over the 6-week treatment period. It is concluded that 2,2′,5′-trihydroxychalcone has the potential to serve as a protective agent for some debilitating diseases.