Biological Versatility Research Articles

Novel imidazoline compounds as partial or full agonists of D 2-like dopamine receptors inspired by I 2-imidazoline binding sites ligand 2-BFI

Based on the well known biological versatility of the imidazoline nucleus, we prepared the novel derivatives 3a– k inspired by 2-BFI scaffold to assess imidazoline molecules as D 2-like dopamine receptor ligands. Conservative chemical modifications of the lead structure, such as the introduction of an hydroxy group in the aromatic ring alone or associated with N-benzyl substitution, provided partial ( 3f) or nearly full ( 3e and 3h) agonists, all endowed with D 2-like potency comparable to that of dopamine.

Effect of Emdogain on proliferation and migration of different periodontal tissue–associated cells

Although Emdogain is widely used as a gel in periodontal therapy, the exact mechanisms underlying its regenerative ability still need to be further investigated. Therefore, we tested in vitro the effect of the product Emdogain on proliferation, viability, and migration of various human cell types of periodontium. Proliferation and viability of alveolar osteoblasts (AOBs), epithelial cell line HSC-2, and human umbilical vein endothelial cells (HUVECs) were measured using [(3)H]-thymidine uptake and 3,4,5-dimethylthiazol-2-yl-2,5-diphenyl tetrazolium bromide (MTT)-assay, respectively. Cell migration was investigated in microchemotaxis chamber. The proliferation and viability of AOB, HSC-2, and HUVECs were significantly stimulated by Emdogain (12.5-250 microg/mL) in direct relationship with the amount of product present in the cell culture medium. Cell migration was stimulated in AOB and HUVECs depending on Emdogain amount. In contrast, in HSC-2 cells the migration was stimulated only by less than 50 microg/mL of Emdogain, whereas at higher amounts this stimulating effect was either diminished or absent. Emdogain stimulates proliferation, viability, and migration of AOB, HSC-2, and HUVECs in vitro. This biological versatility of Emdogain could correspond to an essential mechanism underlying its ability to promote periodontal regeneration.

Brown-Vialetto-Van Laere Syndrome, a Ponto-Bulbar Palsy with Deafness, Is Caused by Mutations in C20orf54

Brown-Vialetto-Van Laere syndrome is a rare neurological disorder with a variable age at onset and clinical course. The key features are progressive ponto-bulbar palsy and bilateral sensorineural deafness. A complex neurological phenotype with a mixed picture of upper and lower motor neuron involvement reminiscent of amyotrophic lateral sclerosis evolves with disease progression. We identified a candidate gene, C20orf54, by studying a consanguineous family with multiple affected individuals and subsequently demonstrated that mutations in this gene were the cause of disease in other, unrelated families.

Structural Insights into the Molecular Mechanisms of Cauliflower Mosaic Virus Transmission by Its Insect Vector

Cauliflower mosaic virus (CaMV) is transmitted from plant to plant through a seemingly simple interaction with insect vectors. This process involves an aphid receptor and two viral proteins, P2 and P3. P2 binds to both the aphid receptor and P3, itself tightly associated with the virus particle, with the ensemble forming a transmissible viral complex. Here, we describe the conformations of both unliganded CaMV P3 protein and its virion-associated form. X-ray crystallography revealed that the N-terminal domain of unliganded P3 is a tetrameric parallel coiled coil with a unique organization showing two successive four-stranded subdomains with opposite supercoiling handedness stabilized by a ring of interchain disulfide bridges. A structural model of virus-liganded P3 proteins, folding as an antiparallel coiled-coil network coating the virus surface, was derived from molecular modeling. Our results highlight the structural and biological versatility of this coiled-coil structure and provide new insights into the molecular mechanisms involved in CaMV acquisition and transmission by the insect vector.

SFRPs: a declaration of (Wnt) independence

Secreted Frizzled-related proteins (sFRPs) are signalling molecules well-known as antagonists of the Wnt pathway, but recent studies indicate that they may have additional functions unrelated to Wnt. A new study demonstrates that mammalian sFRP2 can act as an enhancer of collagen processing in vitro and in vivo, augmenting myocardial injury-driven fibrosis. These findings underscore the biological versatility of sFRP family members.

5′‐Methylaristeromycin and Related Derivatives.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF.

The Cellular Lesion of Humoral Rejection: Predominant Recruitment of Monocytes to Peritubular and Glomerular Capillaries

Accumulation of inflammatory cells within capillaries is a common morphologic feature of humoral renal allograft rejection and is most easily appreciated if it occurs in glomeruli. The aim of our study was to determine the amount and composition of immune cells within glomeruli and peritubular capillaries (PTC) in cellular and humoral allograft rejection. Immunofluorescent double-labeling for CD31 and CD3 or CD68 was used for phenotyping and enumerating immune cells within glomeruli and PTC. The major findings are: (1) accumulation of immune cells in PTC is far more common than it would be anticipated based on the assessment by conventional histology; (2) it is not the absolute number of immune cells accumulating within capillaries, but rather the composition of the intracapillary cell population that distinguishes humoral rejection from cellular rejection and (3) in C4d positive biopsies a predominantly monocytic cell population accumulates not only within glomeruli but also within PTC. The median value of monocyte/T-cell ratio within PTC was 2.3 in C4d positive biopsies but only 1 (p = 0.0008) in C4d negative biopsies. Given their prominent presence within capillaries and their extensive biological versatility monocytes might contribute to the capillary damage observed in acute and chronic allograft rejection.

5‘-Methylaristeromycin and Related Derivatives

The biological versatility of aristeromycin (carbocyclic adenosine) is limited by accompanying cytotoxicity caused ostensibly by the intracellular formation of its 5'-nucleotide derivatives. Aristeromycin derivatives that offered steric interference to this transformation at the C-5' center were sought. This paper describes the facile stereospecific synthesis, where necessary, of such C-5'-methylated aristeromycin derivatives.

The many roles of the class A macrophage scavenger receptor

The class A macrophage scavenger receptor (SR-A) is the prototypic example of a group of plasma membrane receptors collectively known as scavenger receptors. SR-A displays the ability to bind and endocytose large quantities of modified lipoprotein. Hence, it is thought to be one of the main receptors involved in mediating lipid influx into macrophages (Mphi), which promotes their conversion into foam cells that are abundant in the atherosclerotic lesion. However, as a result of increased interest and research effort and through the development of specific reagents and animal models, it is now appreciated to be multifunctional. These roles include Mphi growth and maintenance, adhesion to the substratum, cell-cell interactions, phagocytosis, and host defense. In this review, we attempt to summarize the evidence and argue that these kinds of activities underlie the biological versatility of Mphi.

The Chemical and Biological Versatility of Riboflavin

Since their discovery and chemical characterization in the 1930s, flavins have been recognized as being capable of both one- and two-electron transfer processes, and as playing a pivotal role in coupling the two-electron oxidation of most organic substrates to the one-electron transfers of the respiratory chain. In addition, they are now known as versatile compounds that can function as electrophiles and nucleophiles, with covalent intermediates of flavin and substrate frequently being involved in catalysis. Flavins are thought to contribute to oxidative stress through their ability to produce superoxide, but at the same time flavins are frequently involved in the reduction of hydroperoxides, products of oxygen-derived radical reactions. Flavoproteins play an important role in soil detoxification processes via the hydroxylation of many aromatic compounds, and a simple flavoprotein in liver microsomes catalyses many reactions similar to those carried out by cytochrome P450 enzymes. Flavins are involved in the production of light in bioluminescent bacteria, and are intimately connected with light-initiated reactions such as plant phototropism and nucleic acid repair processes. Recent reports also link them to programmed cell death. The chemical versatility of flavoproteins is clearly controlled by specific interactions with the proteins with which they are bound. One of the main thrusts of current research is to try to define the nature of these interactions, and to understand in chemical terms the various steps involved in catalysis by flavoprotein enzymes.

The Chemical and Biological Versatility of Riboflavin

The Chemical and Biological Versatility of Riboflavin

Recent developments in our knowledge of potato transgenic biology

Transgenic potato plants are being generated world-wide to assess the impact of transgene expression (sense and/or antisense) on parameters as diverse as yield, quality, stress physiology and pest/disease resistance. Strategies for alternative uses of the potato crops by diverting metabolism into high value products or by expressing recombinant proteins are also being explored. Results obtained are often surprising although the science of plant molecular biology is relatively young. Whilst the outcome of any transgenic approach is by no means certain, this review provides sufficient examples to illustrate the versatility and applicability of transgenic biology in potato improvement.

PERSPECTIVE: COMPLEX ADAPTATIONS AND THE EVOLUTION OF EVOLVABILITY.

The problem of complex adaptations is studied in two largely disconnected research traditions: evolutionary biology and evolutionary computer science. This paper summarizes the results from both areas and compares their implications. In evolutionary computer science it was found that the Darwinian process of mutation, recombination and selection is not universally effective in improving complex systems like computer programs or chip designs. For adaptation to occur, these systems must possess "evolvability," i.e., the ability of random variations to sometimes produce improvement. It was found that evolvability critically depends on the way genetic variation maps onto phenotypic variation, an issue known as the representation problem. The genotype-phenotype map determines the variability of characters, which is the propensity to vary. Variability needs to be distinguished from variations, which are the actually realized differences between individuals. The genotype-phenotype map is the common theme underlying such varied biological phenomena as genetic canalization, developmental constraints, biological versatility, developmental dissociability, and morphological integration. For evolutionary biology the representation problem has important implications: how is it that extant species acquired a genotype-phenotype map which allows improvement by mutation and selection? Is the genotype-phenotype map able to change in evolution? What are the selective forces, if any, that shape the genotype-phenotype map? We propose that the genotype-phenotype map can evolve by two main routes: epistatic mutations, or the creation of new genes. A common result for organismic design is modularity. By modularity we mean a genotype-phenotype map in which there are few pleiotropic effects among characters serving different functions, with pleiotropic effects falling mainly among characters that are part of a single functional complex. Such a design is expected to improve evolvability by limiting the interference between the adaptation of different functions. Several population genetic models are reviewed that are intended to explain the evolutionary origin of a modular design. While our current knowledge is insufficient to assess the plausibility of these models, they form the beginning of a framework for understanding the evolution of the genotype-phenotype map.

Nasal Messenger RNA Expression of Interleukins 2, 4, and 5 in Patients with Allergic Rhinitis

In nasal biopsies from 17 adult patients with seasonal allergic rhinitis and from 10 healthy controls, cytokines were analyzed by reverse-transcriptase polymerase chain reaction (RT-PCR). The time-course study during winter included repeated local allergen provocation with subsequent nasal biopsies as well as biopsies taken during pollen season. The RT-PCR for CD44 yielded positive bands in 65 of 71 cases, in which cases mRNA for interleukins 2, 4, and 5 (IL-2, IL-4, and IL-5) were thus investigated by means of seminested PCR. IL-4 mRNA was found almost exclusively in the allergic patients. During provocation a significant increase in IL-4 was noticed compared with controls (p = 0.043). Equally, during the natural pollen season, IL-4 mRNA expression was significantly higher in patients not using nasal corticosteroids compared with those who did (p = 0.011). No differences in IL-2 or IL-5 were observed between the groups. These findings also indicate, together with earlier observations of T-cell activation, a phenotype switch toward T-helper 2 (Th2) cells, and the accumulation (homing) of these T cells in the nasal mucosa, that T cells constitute the main source for IL-4 in the nasal mucosa. Therefore, allergic patients have an increased synthesis of IL-4 when provoked with the allergen, and during natural pollen season this synthesis can be downregulated by corticosteroids. Furthermore, this study exemplifies the versatility of molecular biology in surgical pathology and that even low-copy-number cytokine mRNA can be examined in routinely snap-frozen surgical specimens.

Biological Versatility, Evolution, and Food Resource Exploitation in African Cichlid Fishes

Increased potential versatility in form and function of the feeding apparatus of cichlid fishes has led to a prodigious proliferation in the number of possible functional solutions to an increasing variety of biological problems. Optimal utilization of every conceivable trophic resource in lacustrine environments by just one fish family, the Cichlidae, has been achieved by eruptive evolutionary radiation within the characteristically cichlid body plan producing mechanisms which partition the diverse food resources with extraordinary efficiency therefore minimizing resource sharing. There is a direct relationship between the effectiveness of trophic resource exploitation and the functional integration of the cichlid body plan in which a minimum number of adaptive compromises are necessary to evolve optimal anatomical solutions by rapidly realizable changes Anatomical data presented here reveal that cichlids possess a specific kind of mosaic in which the basic percoid jaw apparatus permits unparalleled optimal adaptations by simple morphogenetic changes while unique and dramatically diverse patterns of muscular coordination involving degrees of synchrony and extensive modulating capabilities of antagonistic muscle groups have been discovered electromyographically. At the same time the highly integrated pharyngeal jaw apparatus is sufficiently specialized providing complete freedom for the jaws to evolve into refined collecting devices. The exceptional evolutionary success of lacustrine cichlids demonstrates how rare and very specific kinds of biologically versatile morphological mosaics represent the best preadaptations for the ancestors of major new taxa. Given identical ecological conditions and temporal factors, a group of organisms possessing such rare mosaics, in which optimal biological versatility is realizable by simple evolutionary mechanisms, will dominate newly formed environments to the detriment of taxa not so endowed.

Recent results on the biochemistry of the cell wall lipopolysaccharides of Salmonella bacteria.

AbstractLipopolysaccharides, which are located in the cell wall of gram‐negative bacteria, are characterized by their biological versatility. They represent the O antigens of the bacteria, they are potent endotoxins, and they often function as the receptor sites for bacteriophages. The study of the mode of action of lipopolysaccharides and the search for structures in the macromolecules that are responsible for biological activity became promising when principles of the chemical fine structure of lipopolysaccharides were identified. The following review summarizes the results of recent investigations regarding the structure of lipopolysaccharides, their biosynthesis and its genetic determination.