Visual Cues Given by Humans Are Not Sufficient for Asian Elephants (Elephas maximus) to Find Hidden Food

Recent research suggests that domesticated species – due to artificial selection by humans for specific, preferred behavioral traits – are better than wild animals at responding to visual cues given by humans about the location of hidden food. \Although this seems to be supported by studies on a range of domesticated (including dogs, goats and horses) and wild (including wolves and chimpanzees) animals, there is also evidence that exposure to humans positively influences the ability of both wild and domesticated animals to follow these same cues. Here, we test the performance of Asian elephants (Elephas maximus) on an object choice task that provides them with visual-only cues given by humans about the location of hidden food. Captive elephants are interesting candidates for investigating how both domestication and human exposure may impact cue-following as they represent a non-domesticated species with almost constant human interaction. As a group, the elephants (n = 7) in our study were unable to follow pointing, body orientation or a combination of both as honest signals of food location. They were, however, able to follow vocal commands with which they were already familiar in a novel context, suggesting the elephants are able to follow cues if they are sufficiently salient. Although the elephants’ inability to follow the visual cues provides partial support for the domestication hypothesis, an alternative explanation is that elephants may rely more heavily on other sensory modalities, specifically olfaction and audition. Further research will be needed to rule out this alternative explanation.     

High Molecular Weight Forms of Mammalian Respiratory Chain Complex II

Mitochondrial respiratory chain is organised into supramolecular structures that can be preserved in mild detergent solubilisates and resolved by native electrophoretic systems. Supercomplexes of respiratory complexes I, III and IV as well as multimeric forms of ATP synthase are well established. However, the involvement of complex II, linking respiratory chain with tricarboxylic acid cycle, in mitochondrial supercomplexes is questionable. Here we show that digitonin-solubilised complex II quantitatively forms high molecular weight structures (CII_hmw) that can be resolved by clear native electrophoresis. CII_hmw structures are enzymatically active and differ in electrophoretic mobility between tissues (500 – over 1000 kDa) and cultured cells (400–670 kDa). While their formation is unaffected by isolated defects in other respiratory chain complexes, they are destabilised in mtDNA-depleted, rho0 cells. Molecular interactions responsible for the assembly of CII_hmw are rather weak with the complexes being more stable in tissues than in cultured cells. While electrophoretic studies and immunoprecipitation experiments of CII_hmw do not indicate specific interactions with the respiratory chain complexes I, III or IV or enzymes of the tricarboxylic acid cycle, they point out to a specific interaction between CII and ATP synthase.     

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...     

The potentiation of myeloperoxidase activity by the glycosaminoglycan-dependent binding of myeloperoxidase to proteins of the extracellular matrix

Background

Myeloperoxidase (MPO) is an abundant hemoprotein expressed by neutrophil granulocytes that is recognized to play an important role in the development of vascular diseases. Upon degranulation from circulating neutrophil granulocytes, MPO binds to the surface of endothelial cells in an electrostatic-dependent manner and undergoes transcytotic migration to the underlying extracellular matrix (ECM). However, the mechanisms governing the binding of MPO to subendothelial ECM proteins, and whether this binding modulates its enzymatic functions are not well understood.

Methods

We investigated MPO binding to ECM derived from aortic endothelial cells, aortic smooth muscle cells, and fibroblasts, and to purified ECM proteins, and the modulation of these associations by glycosaminoglycans. The oxidizing and chlorinating potential of MPO upon binding to ECM proteins was tested.

Results

MPO binds to the ECM proteins collagen IV and fibronectin, and this association is enhanced by the pre-incubation of these proteins with glycosaminoglycans. Correspondingly, an excess of glycosaminoglycans in solution during incubation inhibits the binding of MPO to collagen IV and fibronectin. These observations were confirmed with cell-derived ECM. The oxidizing and chlorinating potential of MPO was preserved upon binding to collagen IV and fibronectin; even the potentiation of MPO activity in the presence of collagen IV and fibronectin was observed.

Conclusions

Collectively, the data reveal that MPO binds to ECM proteins on the basis of electrostatic interactions, and MPO chlorinating and oxidizing activity is potentiated upon association with these proteins.

General significance

Our findings provide new insights into the molecular mechanisms underlying the interaction of MPO with ECM proteins.     

Genetic engineering of cytokinin metabolism: Prospective way to improve agricultural traits of crop plants

Cytokinins (CKs) are ubiquitous phytohormones that participate in development, morphogenesis and many physiological processes throughout plant kingdom. In higher plants, mutants and transgenic cells and tissues with altered activity of CK metabolic enzymes or perception machinery, have highlighted their crucial involvement in different agriculturally important traits, such as productivity, increased tolerance to various stresses and overall plant morphology. Furthermore, recent precise metabolomic analyses have elucidated the specific occurrence and distinct functions of different CK types in various plant species. Thus, smooth manipulation of active CK levels in a spatial and temporal way could be a very potent tool for plant biotechnology in the future. This review summarises recent advances in cytokinin research ranging from transgenic alteration of CK biosynthetic, degradation and glucosylation activities and CK perception to detailed elucidation of molecular processes, in which CKs work as a trigger in model plants. The first attempts to improve the quality of crop plants, focused on cereals are discussed, together with proposed mechanism of action of the responses involved.     

Collagen-binding Microbial Surface Components Recognizing Adhesive Matrix Molecule (MSCRAMM) of Gram-positive Bacteria Inhibit Complement Activation via the Classical Pathway

Members of a family of collagen-binding microbial surface components recognizing adhesive matrix molecules (MSCRAMMs) from Gram-positive bacteria are established virulence factors in several infectious diseases models. Here, we report that these adhesins also can bind C1q and act as inhibitors of the classical complement pathway. Molecular analyses of Cna from Staphylococcus aureus suggested that this prototype MSCRAMM bound to the collagenous domain of C1q and interfered with the interactions of C1r with C1q. As a result, C1r₂C1s₂ was displaced from C1q, and the C1 complex was deactivated. This novel function of the Cna-like MSCRAMMs represents a potential immune evasion strategy that could be used by numerous Gram-positive pathogens.     

Nitrogen, organic carbon and sulphur cycling in terrestrial ecosystems: linking nitrogen saturation to carbon limitation of soil microbial processes

Elevated and chronic nitrogen (N) deposition to N-limited terrestrial ecosystems can lead to ‘N saturation’, with resultant ecosystem damage and leaching of nitrate (NO₃ ^?) to surface waters. Present-day N deposition, however, is often a poor predictor of NO₃ ^? leaching, and the pathway of the ecosystem transition from N-limited to N-saturated remains incompletely understood. The dynamics of N cycling are intimately linked to the associated carbon (C) and sulphur (S) cycles. We hypothesize that N saturation is associated with shifts in the microbial community, manifest by a decrease in the fungi-to-bacteria ratio and a transition from N to C limitation. Three mechanisms could lead to lower amount of bioavailable dissolved organic C (DOC) for the microbial community and to C limitation of N-rich systems: (1) Increased abundance of N for plant uptake, causing lower C allocation to plant roots; (2) chemical suppression of DOC solubility by soil acidification; and (3) enhanced mineralisation of DOC due to increased abundance of electron acceptors in the form of ${{\text{SO}}_{ 4}}^{ 2-}$ SO 4 2 ? and NO₃ ^? in anoxic soil micro-sites. Here we consider each of these mechanisms, the extent to which their hypothesised impacts are consistent with observations from intensively-monitored sites, and the potential to improve biogeochemical models by incorporating mechanistic links to the C and S cycles.