scholarly journals Molecular phylogenetics and generic concepts in the Maxillarieae (Orchidaceae)

Lankesteriana ◽  
2016 ◽  
Vol 3 (2) ◽  
Author(s):  
Norris H. Williams ◽  
W. Mark Whitten
Keyword(s):  
Molecular Phylogenetics ◽  
Title Page ◽  
Reward Systems ◽  
Wide Range ◽  
Euglossine Bee ◽  
Nectar Rewards ◽  
Pollination Systems

<div class="page" title="Page 1"><div class="layoutArea"><div class="column"><p><span>Tribe Maxillarieae account for approximately 10% (&gt;2800 species) of Orchidaceae and are a major com- ponent of the Neotropical epiphytic flora. Pollination systems include 1) male euglossine-bee fragrance rewards in four subtribes, 2) oil reward systems and mimicry in some groups, 3) nectar rewards in a wide range of taxa, and 4) pseudocopulation in some Maxillariinae and some Oncidiinae. </span></p></div></div></div>

scholarly journals Molecular phylogenetics of mormolyca (orchidaceae: maxillariinae) based on combined molecular data sets

Lankesteriana ◽  
2013 ◽  
Author(s):  
Rafael Arévalo ◽  
Kenneth M. Cameron
Keyword(s):  
Molecular Phylogenetics ◽  
Sequence Data ◽  
Intergenic Spacer ◽  
Molecular Data ◽  
Data Sets ◽  
History Of ◽  
Trnk Intron ◽  
Vegetative Characters ◽  
High Level ◽  
Pollination Systems

The Neotropical orchid genus Mormolyca Fenzl, as currently circumscribed, encompasses a diverse group of ca. 27species. Many of these were included traditionally in Maxillaria sect. Rufescens, when similarity of floral morphology was considered foremost in their classification rather than the evolutionary history of the taxa. In order to begin revising species delimitation and clarifying the evolution and biology of the genus, we present a phylogenetic hypothesis using sequence data from five plastid loci (rpoC1, matK gene and flanking trnK intron, atpB-rbcL intergenic spacer, and the 3’ portion of ycf1) and the nuclear ribosomal internal and external transcribed spacers (ITS, ETS). Resulting trees using both Bayesian and parsimony inference are congruent with each other, and generally well resolved. Based on current level of sampling across Maxillariinae, these molecular data support the monophyly of Mormolyca and shed light on the interspecific phylogenetic patterns within the genus. These include an early divergent paraphyletic grade of Mormolyca species successively sister to a clade with at least two definable subclades within. The latter are characterized by two different flower morphologies that are likely related to their pollination systems. Although not all relationships within the genus are fully resolved or supported, these results offer a first glimpse into the phylogeny of a small group of epiphytic orchids characterized by an unusually high level of variable vegetative characters, floral fragrance profiles, and pollination systems.

An improved amplification and sequencing strategy for phylogenetic studies using the mitochondrial large subunit rRNA gene

Genome ◽  
1996 ◽  
Vol 39 (4) ◽  
pp. 793-797 ◽  
Author(s):  
Alex Parker ◽  
Irv Kornfield
Keyword(s):  
16S Rrna ◽  
Molecular Phylogenetics ◽  
Large Subunit ◽  
Ribosomal Subunit ◽  
Variable Region ◽  
Rrna Gene ◽  
Molecular Systematic ◽  
Wide Range ◽  
Sequencing Strategy ◽  
Large Subunit Rrna

Numerous molecular systematic studies have employed variation in the mitochondrial large subunit (16s) rRNA gene to infer patterns of relationship among species and higher taxa. The primers most commonly employed in 16s rRNA amplification and sequencing bracket an approximately 600 bp portion of this gene. However, most of the informative variation occurs within a 200 bp subset of this segment. We describe a novel primer pair designed to amplify this variable region in a wide range of taxa, allowing broader application and considerable streamlining of data acquisition for studies using this gene. Key words : molecular phylogenetics, polymerase chain reaction, mtDNA, large ribosomal subunit, control region.

scholarly journals Teaching the Process of Molecular Phylogeny and Systematics: A Multi-Part Inquiry-Based Exercise

2010 ◽  
Vol 9 (4) ◽  
pp. 513-523 ◽  
Author(s):  
Nathan H. Lents ◽  
Oscar E. Cifuentes ◽  
Anthony Carpi
Keyword(s):  
Molecular Phylogeny ◽  
Dna Sequences ◽  
Molecular Phylogenetics ◽  
Homo Sapiens ◽  
Molecular Data ◽  
Biology Students ◽  
Living Things ◽  
Wide Range ◽  
Shared Ancestry ◽  
Introductory Biology Course

Three approaches to molecular phylogenetics are demonstrated to biology students as they explore molecular data from Homo sapiens and four related primates. By analyzing DNA sequences, protein sequences, and chromosomal maps, students are repeatedly challenged to develop hypotheses regarding the ancestry of the five species. Although these exercises were designed to supplement and enhance classroom instruction on phylogeny, cladistics, and systematics in the context of a postsecondary majors-level introductory biology course, the activities themselves require very little prior student exposure to these topics. Thus, they are well suited for students in a wide range of educational levels, including a biology class at the secondary level. In implementing this exercise, we have observed measurable gains, both in student comprehension of molecular phylogeny and in their acceptance of modern evolutionary theory. By engaging students in modern phylogenetic activities, these students better understood how biologists are currently using molecular data to develop a more complete picture of the shared ancestry of all living things.

scholarly journals Furofuran lignans of Artemisia genus: Isolation, biosynthesis and biological activity

2020 ◽  
Vol 85 (5) ◽  
pp. 575-600
Author(s):  
Jovana Ickovski ◽  
Jovana Pavlovic ◽  
Milan Mitic ◽  
Ivan Palic ◽  
Danijela Kostic ◽  
...  
Keyword(s):  
Molecular Phylogenetics ◽  
Sesquiterpene Lactones ◽  
Economic Value ◽  
Individual Species ◽  
Isolation And Identification ◽  
Biological Potential ◽  
Wide Range ◽  
Pharmacological Interest ◽  
Large Genus ◽  
Pharmacologically Active

Since ancient times, medicinal plants and pharmacologically active products obtained from different natural sources play an important role in human health. Plants belonging to the genus Artemisia possess a great biological potential and it is a well-studied genus in the fields such as systematics (including molecular phylogenetics) and genome organization. Many species of the genus (e.g., A. absinthium, A. annua, A. vulgaris, A. abrotanum, A. arborescens) are widely exploited, because of their high economic value as medicines, food and ornamentals. Withal, in such a large genus, some hiatus must inevitably exist, concerning attainments and potentials that individual species possess. Most of the studies are focused on bioactivity and pharmacology of sesquiterpene lactones. Lignans are unjustly neglected, even though they as well exhibit a wide range of bioactivities. Motivated by that fact, we tried to consolidate findings on bioactive lignans accumulated through the years, with the logical perspectives on further work on isolation and identification of new bioactive lignans and the exploitation of lignans as substances of potential pharmacological interest.

scholarly journals Floral mimicry in Oncidioid orchids

Lankesteriana ◽  
2016 ◽  
Vol 3 (2) ◽  
Author(s):  
Martyn P. Powell ◽  
Franco Pupulin ◽  
Jorge Warner ◽  
Mark W. Chase ◽  
Vincent Savolainen
Keyword(s):  
Sea Level ◽  
Title Page ◽  
Floral Mimicry ◽  
Wide Range ◽  
Tropical America

<div class="page" title="Page 1"><div class="layoutArea"><div class="column"><p><span>Extensive radiation in oncidioid orchids (subtribe Oncidiinae) has resulted in over 1,700 species in tropical America in some 70 genera. They exhibit a wide range of habitats, occurring terrestrially or, more commonly, epiphytically and can be found from sea level to the Andean paramós and from deserts to rainforests. </span></p></div></div></div>

scholarly journals Note to Self: Stop Calling Interfaces “Natural”

2015 ◽  
Vol 1 (1) ◽  
pp. 4 ◽  
Author(s):  
Lone Koefoed Hansen ◽  
Peter Dalsgaard
Keyword(s):  
Title Page ◽  
Brain Computer Interfaces ◽  
Computer Interfaces ◽  
Clear Explanation ◽  
Wide Range

<div class="page" title="Page 1"><div class="layoutArea"><div class="column"><p><span>The term “natural” is employed to describe a wide range of novel interactive products and systems, ranging from ges- ture-based interaction to brain-computer interfaces and in marketing as well as in research. However, this terminology is problematic. It establishes an untenable dichotomy be- tween forms of interaction that are natural and those that are not; it draws upon the positive connotations of the term and conflates the language of research with marketing lingo, often without a clear explanation of why novel interfaces can be considered natural; and it obscures the examination of the details of interaction that ought to be the concern of HCI researchers. We are primarily concerned with identify- ing the problem, but also propose two steps to remedy it: recognising that the terminology we employ in research has consequences, and unfolding and articulating in more detail the qualities of interfaces that we have hitherto labelled “natural”. </span></p></div></div></div>

scholarly journals Neglecting model selection alters phylogenetic inference

2019 ◽  
Author(s):  
Michael Gerth
Keyword(s):  
Model Selection ◽  
Molecular Phylogenetics ◽  
Negative Impact ◽  
Model Fitting ◽  
Phylogenetic Reconstruction ◽  
Evolutionary Model ◽  
Sequence Alignments ◽  
Modern Biology ◽  
Wide Range ◽  
History Of

ABSTRACTMolecular phylogenetics is a standard tool in modern biology that informs the evolutionary history of genes, organisms, and traits, and as such is important in a wide range of disciplines from medicine to palaeontology. Maximum likelihood phylogenetic reconstruction involves assumptions about the evolutionary processes that underlie the dataset to be analysed. These assumptions must be specified in forms of an evolutionary model, and a number of criteria may be used to identify the best-fitting from a plethora of available models of DNA evolution. Using many empirical and simulated nucleotide sequence alignments, Abadi et al.1 have recently found that phylogenetic inferences using best models identified by six different model selection criteria are, on average, very similar to each other. They further claimed that using the model GTR+I+G4 without prior model-fitting results in similarly accurate phylogenetic estimates, and consequently that skipping model selection entirely has no negative impact on many phylogenetic applications. Focussing on this claim, I here revisit and re-analyse some of the data put forward by Abadi et al. I argue that while the presented analyses are sound, the results are misrepresented and in fact - in line with previous work - demonstrate that model selection consistently leads to different phylogenetic estimates compared with using fixed models.

Recent Applications of High Resolution Electron Microscopy to Crystalline Arrays of Virus Particles

1978 ◽  
Vol 36 (3) ◽  
pp. 470-482 ◽  
Author(s):  
R.W. Horne
Keyword(s):  
Electron Microscopy ◽  
Image Processing ◽  
Analytical Techniques ◽  
Staining Technique ◽  
High Resolution Electron Microscopy ◽  
Optical Diffraction ◽  
Full Potential ◽  
Virus Particles ◽  
Resolution Electron ◽  
Wide Range

The technique of surrounding virus particles with a neutralised electron dense stain was described at the Fourth International Congress on Electron Microscopy, Berlin 1958 (see Home & Brenner, 1960, p. 625). For many years the negative staining technique in one form or another, has been applied to a wide range of biological materials. However, the full potential of the method has only recently been explored following the development and applications of optical diffraction and computer image analytical techniques to electron micrographs (cf. De Hosier & Klug, 1968; Markham 1968; Crowther et al., 1970; Home & Markham, 1973; Klug & Berger, 1974; Crowther & Klug, 1975). These image processing procedures have allowed a more precise and quantitative approach to be made concerning the interpretation, measurement and reconstruction of repeating features in certain biological systems.

Microfabrication research at the National Submicron Facility

1983 ◽  
Vol 41 ◽  
pp. 86-89
Author(s):  
E.D. Wolf
Keyword(s):  
Integrated Circuits ◽  
Particle Physics ◽  
High Speed ◽  
New Technology ◽  
High Energy ◽  
High Energy Particle ◽  
New Science ◽  
Wide Range ◽  
Intermediate Domain ◽  
Circuit Function

Most microelectronics devices and circuits operate faster, consume less power, execute more functions and cost less per circuit function when the feature-sizes internal to the devices and circuits are made smaller. This is part of the stimulus for the Very High-Speed Integrated Circuits (VHSIC) program. There is also a need for smaller, more sensitive sensors in a wide range of disciplines that includes electrochemistry, neurophysiology and ultra-high pressure solid state research. There is often fundamental new science (and sometimes new technology) to be revealed (and used) when a basic parameter such as size is extended to new dimensions, as is evident at the two extremes of smallness and largeness, high energy particle physics and cosmology, respectively. However, there is also a very important intermediate domain of size that spans from the diameter of a small cluster of atoms up to near one micrometer which may also have just as profound effects on society as “big” physics.

Application of TEM to Deformation, Wear, and Fracture of Ceramics

1974 ◽  
Vol 32 ◽  
pp. 472-473
Author(s):  
B. J. Hockey
Keyword(s):  
Wear Resistance ◽  
High Temperature ◽  
Mechanical Behavior ◽  
Brittle Materials ◽  
High Temperature Strength ◽  
Wide Range ◽  
Corrosive Environments ◽  
Further Development

Ceramics, such as Al2O3 and SiC have numerous current and potential uses in applications where high temperature strength, hardness, and wear resistance are required often in corrosive environments. These materials are, however, highly anisotropic and brittle, so that their mechanical behavior is often unpredictable. The further development of these materials will require a better understanding of the basic mechanisms controlling deformation, wear, and fracture.The purpose of this talk is to describe applications of TEM to the study of the deformation, wear, and fracture of Al2O3. Similar studies are currently being conducted on SiC and the techniques involved should be applicable to a wide range of hard, brittle materials.

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