Phylogenetic systematics comprise the principles and methods by which we reconstruct the evolutionary history (phylogeny) of organisms and transform this reconstruction into a biological classification of these organisms. The most important progress in designing the tools for phylogenetic reconstruction was initiated by the German entomologist Willi Hennig (1913-1976), who clarified or redefined the goals of phylogenetic systematics in a book published in 1950: Grundzüge einer Theorie der phylogenetischen Systematik. An extensively revised, English translation was published in 1966: Phylogenetic Systematics. W. Hennig's "phylogenetic systematics" undoubtedly was a very significant contribution to systematics, by some systematists and philosophers even characterized as a "revolution". Hennig's redefinition and clarification of the concepts of monophyly and phylogenetic relationships created a sound foundation for systematics in general. After decades of focussing on species-level problems, Hennig redirected the interest of systematists towards the study of higher taxa and the reconstruction of phylogenetic relationships between them. A phylogenetic system is now almost universally accepted as the most useful general reference system for biology. It has been able to accommodate new developments in systematics (such as quantitative cladistics and molecular systematics), evolutionary biology (such as ecological phylogenetics), and historical biogeography.
Fragile X syndrome (FXS) is the most frequently inherited form of intellectual disability and prevalent single-gene cause of autism. A priority of FXS research is to determine the molecular mechanisms underlying the cognitive and social functioning impairments in humans and the FXS mouse model. Glutamate ionotropic alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptors (AMPARs) mediate a majority of fast excitatory neurotransmission in the central nervous system and are critically important for nearly all aspects of brain function, including neuronal development, synaptic plasticity, and learning and memory. Both preclinical and clinical studies have indicated that expression, trafficking, and functions of AMPARs are altered and result in altered synapse development and plasticity, cognitive impairment, and poor mental health in FXS. In this review, we discuss the contribution of AMPARs to disorders of FXS by highlighting recent research advances with a specific focus on change in AMPARs expression, trafficking, and dependent synaptic plasticity. Since changes in synaptic strength underlie the basis of learning, development, and disease, we suggest that the current knowledge base of AMPARs has reached a unique point to permit a comprehensive re-evaluation of their roles in FXS.
In summer 2008, the Orthopteran species Chorthippus biguttulus, Myrmeleotettix maculatus (Caelifera), Decticus verrucivorus and Platycleis albopunctata (Ensifera) were sampled in coastal heathland on the German Baltic Sea island of Hiddensee. The aim of this study was to assess differences in abundance of Orthoptera in three different habitats and determine the importance of habitat mosaics. Distribution patterns varied among species and total abundance of Orthoptera differed significantly among the three habitats. Due to species-specific habitat preferences the Caelifera were most abundant in grey dunes and the Ensifera in dwarf-shrub heath adjoining grey dunes. In conclusion, grey dunes are a suitable habitat for the Caelifera studied, while the Ensifera require a heathland mosaic consisting of both grey dunes and dwarf shrub vegetation.
While the key role of termites in the decomposition of litter in the tropics has been acknowledged for a long time, much less information exists on their importance in the recycling of dung of primary consumers, especially herbivores. A review of published studies shows that a diverse group of termites (at least 126 species) has been reported to feed on a wide range of mammalian dung (18 species). Predominantly, wood-feeding and polyphagous wood-litter feeding species were found to feed also frequently on dung. Moreover, we found that termites can quickly remove large amounts of mammalian dung, especially in the dry season, when on average about 1/3 of the dung deposited in a given habitat is removed by termites within one month (with the highest rates observed in savannas). No distinctive preference for mammalian dung over other organic food sources was observed for fungus-growing termites (Macrotermitinae), whereas the majority of the non-fungus growing taxa studied prefer dung over other food. As termites bring large quantities of dung below the soil surface, disturb and enrich soils with nutrients, dung feeding by termites appears to be a previously underestimated process important in the functioning of tropical ecosystems.
Catecholaminergic system plays an important role in hypertension development. The available results on mRNA expression of catecholaminergic system genes in spontaneously hypertensive rats (SHR) are often contradictory. One of the possible causes might be the use of various reference genes as internal controls. In the present study, we searched for suitable reference genes in adrenal medulla or sympathetic ganglia of SHR and Wistar-Kyoto (WKY) rats, which would enable reliable comparison of mRNA expression between these two strains. The mRNA expression was measured by quantitative real-time PCR in adrenal medulla and superior cervical ganglia of 4-week-old or 24-week-old SHR and WKY rats. We evaluated 12 reference genes by three software tools (Normfinder, BestKeeper, geNorm) and compared them for the standardization of mRNA expression. Combination of reference genes Hprt1 and Ywhaz in adrenal medulla and Gapdh and 18S in sympathetic ganglia were chosen as the best ones. 18S was found as applicable reference gene in both tissues. We found many alterations in expression of catecholaminergic system genes in adrenal medulla and sympathetic ganglia of SHR. The usage of the most or the least stable reference gene as internal control changed results moderately in sympathetic ganglia but seriously in adrenal medulla. For example, tyrosine hydroxylase (Th) gene was underexpressed in adrenal medulla of adult SHR using the appropriate reference gene but unchanged after the standardization to the least stable reference gene. Our results indicate the importance of appropriate internal control. The suitability of reference genes should be checked again in the case of change in experimental conditions., A. Vavřínová, M. Behuliak, J. Zicha., and Obsahuje bibliografii
Adenine-induced model of chronic kidney disease (CKD) is a widely used model especially in studies testing novel nephroprotective agents. We investigated the effects of adenineinduced CKD in rats on the activities of some xenobiotic metabolizing enzymes in liver and kidneys, and on some in vivo indicators of drug metabolism (viz pentobarbitone sleeping time, and plasma concentration of theophylline 90 min post administration). CKD was induced by orally feeding adenine (0.25 % w/w) for 35 days. Adenine induced all the characteristics of CKD, which was confirmed by biochemical and histological findings. Glutathione concentration and activities of some enzymes involved in its metabolism were reduced in kidneys and livers of rats with CKD. Renal CYP450 1A1 activity was significantly inhibited by adenine, but other measured isoenzymes (1A2, 3A4 and 2E1) were not significantly affected. Adenine significantly prolonged pentobarbitone-sleeping time and increased plasma theophylline concentration 90 min post administration. Adenine also induced a moderate degree of hepatic damages as indicated histologically and by significant elevations in some plasma enzymes. The results suggest that adenine-induced CKD is associated with significant in vivo inhibitory activities on some drug-metabolizing enzymes, with most of the effect on the kidneys rather than the liver., M. Al Za’abi, A. Shalaby, P. Manoj, B. H. Ali., and Obsahuje bibliografii
For an ordered set W = {w1, w2, . . . , wk} of vertices in a connected graph G and a vertex v of G, the code of v with respect to W is the k-vector cW (v) = (d(v, w1), d(v, w2), . . . , d(v, wk)). The set W is an independent resolving set for G if (1) W is independent in G and (2) distinct vertices have distinct codes with respect to W. The cardinality of a minimum independent resolving set in G is the independent resolving number ir(G). We study the existence of independent resolving sets in graphs, characterize all nontrivial connected graphs G of order n with ir(G) = 1, n − 1, n − 2, and present several realization results. It is shown that for every pair r, k of integers with k ≥ 2 and 0 ≤ r ≤ k, there exists a connected graph G with ir(G) = k such that exactly r vertices belong to every minimum independent resolving set of G.
We show that the index defined via a trace for Fredholm elements in a Banach algebra has the property that an index zero Fredholm element can be decomposed as the sum of an invertible element and an element in the socle. We identify the set of index zero Fredholm elements as an upper semiregularity with the Jacobson property. The Weyl spectrum is then characterized in terms of the index., Jacobus J. Grobler, Heinrich Raubenheimer, Andre Swartz., and Obsahuje seznam literatury
By a ternary structure we mean an ordered pair (X0, T0), where X0 is a finite nonempty set and T0 is a ternary relation on X0. By the underlying graph of a ternary structure (X0, T0) we mean the (undirected) graph G with the properties that X0 is its vertex set and distinct vertices u and v of G are adjacent if and only if {x ∈ X0 ; T0(u, x, v)}∪{x ∈ X0 ; T0(v,x,u)} = {u, v}. A ternary structure (X0, T0) is said to be the B-structure of a connected graph G if X0 is the vertex set of G and the following statement holds for all u, x,y ∈ X0: T0(x, u, y) if and only if u belongs to an induced x − y path in G. It is clear that if a ternary structure (X0, T0) is the B-structure of a connected graph G, then G is the underlying graph of (X0, T0). We will prove that there exists no sentence σ of the first-order logic such that a ternary structure (X0, T0) with a connected underlying graph G is the B-structure of G if and only if (X0, T0) satisfies σ.