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PubMed2003

Phylogenetic significance of morphological characters in the taxonomy of Pestalotiopsis species.

There has been considerable disagreement regarding the relationships among Pestalotiopsis species and their delimitations. A molecular phylogenetic analysis was conducted on 32 species of Pestalotiopsis in order to evaluate the utility of morphological characters currently used in their taxonomy. Phylogenetic relationships were inferred from nucleotide sequences in the ITS regions and 5.8S gene of the rDNA under four optimality criteria: maximum parsimony, weighted parsimony, maximum likelihood, and neighbor joining. Phylogenies estimated from all analyses yielded trees of essentially similar topology and revealed 3 major groups that correspond with morphology-based classification systems. Molecular data indicated that the genus contains two distinct lineages based on pigmentation of median cells and four distinct groupings based on morphology of apical appendages. The analyses did not support reliability of other phenotypic characters of this genus, such as spore dimensions. Characters with particular phylogenetic significance are discussed in relation to the taxonomy of Pestalotiopsis.

Ascomycota↗
PubMed1996

Interactions of selection, linkage and drift in the dynamics of polygenic characters.

We study the dynamics under directional truncation selection of the genetic variability of a quantitative character controlled by a finite number of possibly linked loci with additive effects. After the first generation of selection, the build-up of linkage disequilibria (Bulmer effect) is analytically demonstrated from a genetical point of view in an infinite population. In the following generations, the dynamics of the system in a finite population are predicted using analytic recurrences under a multi-normal approximation, and computer simulations. The effects of recombination on the dynamics of linkage disequilibria induced by selection and drift, and the consequences for the additive genetic variance are then analysed and discussed from the simulation results. Compared to the rapid exploitation of genetic variability promoted by high recombination rates, low recombination rates promote an early storage of genetic variability in repulsion associations of alleles and a possible late release of genetic variance in the population, so that the variability of the character may be maintained over a longer period of time. In some cases, favourable recombination events in tightly linked systems induce an increase of the additive variance of the character, which may explain some results observed in long-term selection experiments. Our results emphasize that the joint effects of selection, linkage and drift must not be neglected in theoretical quantitative genetics, and require further investigation.

Computer Simulation↗
PubMed1984

Studies of antigens in Plasmodium yoelii. II. Inheritance and recombination of antigenic characters.

The inheritance of an antigen designated Py-1 in the rodent malaria parasite Plasmodium yoelii has been investigated. A cross was made between 2 lines differing in the electrophoretic mobility and quantity of Py-1 detected by crossed immunoelectrophoresis. In 10 clones isolated from the progeny of the cross the level of Py-1 always correlated with the virulence of the infection and it was concluded that these characters were different phenotypic effects of the same gene mutation. The electrophoretic mobility of Py-1 segregated independently of the virulence character and was therefore controlled by a different gene. These two antigenic markers also recombined with isoenzyme and drug-sensitivity characters distinguishing the parent lines.

Animals↗
PubMed2004

Excited-state characters and dynamics of [W(CO)(5)(4-cyanopyridine)] and [W(CO)(5)(piperidine)] studied by picosecond time-resolved IR and resonance Raman spectroscopy and DFT calculations: roles of W --> L and W --> CO MLCT and LF excited states revised.

The characters, dynamics, and relaxation pathways of low-lying excited states of the complexes [W(CO)(5)L] [L = 4-cyanopyridine (pyCN) and piperidine (pip)] were investigated using theoretical and spectroscopic methods. DFT calculations revealed the delocalized character of chemically and spectroscopicaly relevant molecular orbitals and the presence of a low-lying manifold of CO pi-based unoccupied molecular orbitals. Traditional ligand-field arguments are not applicable. The lowest excited states of [W(CO)(5)(pyCN)] are W --> pyCN MLCT in character. They are closely followed in energy by W --> CO MLCT states. Excitation at 400 or 500 nm populates the (3)MLCT(pyCN) excited state, which was characterized by picosecond time-resolved IR and resonance Raman spectroscopy. Excited-state vibrations were assigned using DFT calculations. The (3)MLCT(pyCN) excited state is initially formed highly excited in low-frequency vibrations which cool with time constants between 1 and 20 ps, depending on the excitation wavelength, solvent, and particular high-frequency nu(CO) or nu(CN) mode. The lowest excited states of [W(CO)(5)(pip)] are W --> CO MLCT, as revealed by TD-DFT interpretation of a nanosecond time-resolved IR spectrum that was measured earlier in a low-temperature glass (Johnson, F. P. A.; George, M. W.; Morrison, S. L.; Turner, J. J. J. Chem. Soc., Chem. Commun. 1995, 391-393). MLCT(CO) excitation involves transfer of electron density from the W atom and, to a lesser extent, the trans CO to the pi orbitals of the four cis CO ligands. Optical excitation into MLCT(CO) transition of either complex in fluid solution triggers femtosecond dissociation of a W-N bond, producing [W(CO)(5)(solvent)]. It is initially vibrationally excited both in nu(CO) and anharmonicaly coupled low-frequency modes. Vibrational cooling occurs with time constants of 16-22 ps while the intramolecular vibrational energy redistribution from the v = 1 nu(CO) modes is much slower, 160-220 ps. No LF excited states have been found for the complexes studied in a spectroscopically relevant range up to 6-7 eV. It follows that spectroscopy, photophysics, and photochemistry of [W(CO)(5)L] and related complexes are well described by an interplay of close-lying MLCT(L) and MLCT(CO) excited states. The high-lying LF states play only an indirect photochemical role by modifying potential energy curves of MLCT(CO) states, making them dissociative.

Journal Article↗
PubMed2002

Cross-modulation of physicochemical character of aglycones in dinucleoside (3'-->5') monophosphates by the nearest neighbor interaction in the stacked state.

Each nucleobase in a series of stacked dinucleoside (3'-->5') monophosphates, in both acidic and alkaline pH, shows ((1)H NMR) not only its own pK(a) but also the pK(a) of the neighboring nucleobase as a result of cross-modulation of two-coupled pi systems of neighboring aglycones. This means that the electronic character of two nearest neighbors are not like the monomeric counterparts anymore; they have simultaneously changed, almost quantitatively, to something that is a hybrid of the two due to two-way transmission of charge (i.e. 3'-->5' as well as 5'-->3'). This change is permanent due to total modulation of each others pseudoaromatic character by intramolecular stacking, which can be tuned by the nature of the medium across the whole pH range. The small difference observed in the pK(a) of the dimer compared to the monomer is a result of the change in microenvironment in the former. The charge transfer takes place between two stacked nucleobases from the negatively charged end because of the attempt to minimize the charge difference between the two neighboring pseudoaromatic aglycones. Experimental evidence points that the charge transmission in the stacked state takes place by atom-pisigma interaction between nearest neighbor nucleobases in 1-6. The net result of this cross-talk between two neighboring aglycones is a unique set of aglycones in an oligo- or polynucleotide, whose physicochemical property and the pseudoaromatic character are completely dependent both upon the sequence makeup, and whether they are stacked or unstacked. Thus, the physicochemical property of individual nucleobases in an oligonucleotide is determined in a tunable manner, depending upon who the nearest neighbors are, which may have considerable implication in the specific ligand binding ability of an aptamer, the pK(a) and the hydrogen bonding ability in a microenvironment, in the use of codon triplets in the protein biosynthesis or in the triplet usage by the anticodon-codon interaction.

Carbohydrate Conformation↗
PubMed2001

Phylogeny of the Acanthocephala based on morphological characters.

Only four previous studies of relationships among acanthocephalans have included cladistic analyses, and knowledge of the phylogeny of the group has not kept pace with that of other taxa. The purpose of this study is to provide a more comprehensive analysis of the phylogenetic relationships among members of the phylum Acanthocephala using morphological characters. The most appropriate outgroups are those that share a common early cell-cleavage pattern (polar placement of centrioles), such as the Rotifera, rather than the Priapulida (meridional placement of centrioles) to provide character polarity based on common ancestry rather than a general similarity likely due to convergence of body shapes. The phylogeny of 22 species of the Acanthocephala was evaluated based on 138 binary and multistate characters derived from comparative morphological and ontogenetic studies. Three assumptions of cement gland structure were tested: (i) the plesiomorphic type of cement glands in the Rotifera, as the sister group, is undetermined; (ii) non-syncytial cement glands are plesiomorphic; and (iii) syncytial cement glands are plesiomorphic. The results were used to test an early move of Tegorhynchus pectinarius to Koronacantha and to evaluate the relationship between Tegorhynchus and Illiosentis. Analysis of the data-set for each of these assumptions of cement gland structure produced the same single most parsimonious tree topology. Using Assumptions i and ii for the cement glands, the trees were the same length (length = 404 steps, CI = 0.545, CIX = 0.517, HI = 0.455, HIX = 0.483, RI = 0.670, RC = 0.365). Using Assumption iii, the tree was three steps longer (length = 408 steps, CI = 0.539, CIX = 0.512, HI = 0.461, HIX = 0.488, RI = 0.665, RC = 0.359). The tree indicates that the Palaeacanthocephala and Eoacanthocephala both are monophyletic and are sister taxa. The members of the Archiacanthocephala are basal to the other two clades, but do not themselves form a clade. The results provide strong support for the Palaeacanthocephala and the Eoacanthocephala and the hypothesis that the Eoacanthocephala is the most primitive group is not supported. Little support for the Archiacanthocephala as a monophyletic group was provided by the analysis. Support is provided for the recognition of Tegorhynchus and Illiosentis as distinct taxa, as well as the transfer of T. pectinarius to Koronacantha.

Acanthocephala↗
PubMed2001

Segmentation and selection of appropriate Chinese characters in writing place names in Japanese.

This paper explores the relation between an unknown place name written in hiragana (a Japanese syllabary) and its corresponding written representation in kanji (Chinese characters). We propose three principles as those operating in the selection of the appropriate Chinese characters in writing unknown place names. The three principles are concerned with the combination of on and kun readings (zyuubako-yomi), the number of segmentations, and the bimoraicity characteristics of kanji chosen. We performed two experiments to test the principles; the results supported our hypotheses. These results have some implications for the structure of the Japanese mental lexicon, for the processing load in the use of Chinese characters, and for Japanese prosody and morphology.

Adult↗
PubMed2003

Complex inheritance of male courtship song characters in Drosophila virilis.

We analyzed the inheritance of two male courtship song characters, number of pulses in a pulse train, and length of a pulse train in Drosophila virilis. Biometric analyses of song differences among 16 crosses over three generations (parental and reciprocal F1, F2, and backcrosses) were performed using two different approaches. The joint scaling test revealed significant additive and dominance components, and also significant additive interaction between maternal and progeny genotypes. The direction of dominance was toward shorter and denser pulses in D. virilis. In addition, planned comparisons (contrast analyses of variance) between different generations revealed significant Y chromosomal and transient maternal factors and their interactions, with all other factors contributing to differences in the means of song characters. These results suggest that the genetic basis of courtship song characters in D. virilis is primarily of autosomal polygenic nature, with small but significant Y chromosomal and nonchromosomal maternal effects.

Animal Communication↗
PubMed2003

Patterns of changes in temperament and character inventory scales in subjects with obsessive-compulsive disorder following a 4-month treatment.

OBJECTIVE: The purpose of this study was to assess changes in the temperament and character patterns in subjects with obsessive-compulsive disorder (OCD) following the treatment for obsessive/compulsive and accompanying depressive symptoms. METHOD: Study subjects were 35 patients who met the DSM-IV criteria for OCD. All subjects were assessed with the Temperament and Character Inventory (TCI), the Yale-Brown Obsessive-Compulsive Scale, the Beck Depression Inventory, and the Beck Anxiety Inventory before and after a 4-month treatment. RESULTS: Harm Avoidance (HA) scores in OCD subjects before treatment significantly decreased after treatment. However, the Self-Directedness scores, which were significantly lower than healthy comparison subjects before treatment, did not change. In addition, Reward Dependence scores in OCD subjects, which were not significantly different from healthy comparison subjects before treatment, significantly increased after treatment. CONCLUSION: The TCI pattern of untreated OCD subjects (high HA and low Self-Directedness, relative to healthy comparison subjects) and the decrease of HA scores and no change in Self-Directedness scores following a successful treatment suggest that temperaments are more amenable to treatment than characters.

Adolescent↗
PubMed1995

Heritability of a sexually selected character expressed in both sexes.

Sexual selection is thought to be responsible for the evolution of exaggerated male characters and of female mate preferences. Evolutionary mechanisms driven by an advantage to the progeny are only effective if the preferred character has a large genetic component of variance; in most systems in which sexual selection operates, little is known of the relevant genetics. We have measured parent-offspring correlations, and report here that the preferred character (adult size) in seaweed flies has large additive genetic variance in males, but not in females. Virtually all the variance in male size is attributable to a chromosomal inversion system and, consequently, because this system is also a major determinant of larval viability, male size could be used by females as a reliable indicator of offspring survival.

Animals↗
PubMed1975

Genetic differences between the Chinese and European races of the common carp. II. Multi-character variation-a response to the diverse methods of fish cultivation in Europe and China.

The European and Chinese races of the common carp and their F1 crossbreds were tested in five experimental environments. The two races differ widely and conspicuously in many characters. The Chinese carp has poorer growth rate but higher viability and fertility, earlier sexual maturity, higher resistance to crowding, better adaptation to unfavourable pond conditions, higher seine escapability, longer body and larger weight differences between females and males. The crossbreds between the two races are intermediate in some characters (differences in weight between females and males and seine escapability). In other characters (weight gain, specific adaptation to poor conditions and viability), the crossbreds showed dominance or even heterosis. An hypothesis was advanced to explain these genetic differences in terms of selection response to the different fish-farming practices that existed in the two regions. Specific suggestions were made for implementation of the present findings to genetic improvement of carp breeding stocks.

Animals↗
PubMed1991

Relationship between allozymes, heterozygosity and morphological characters in red deer (Cervus elaphus), and the influence of selective hunting on allele frequency distribution.

Morphological characters in red deer (Cervus elaphus), which serve as criteria for selective hunting, were examined in relation to electrophoretic variation in three populations from the Vosges in eastern France. From the polymorphic loci examined, certain alleles at Idh-2, Me-1 and Acp-1 showed significant associations with a special development of body and antler characters selected for by hunters. Idh-2(125) was associated with larger hind foot length in females and a higher number of antler points in males. Me-1(90) and Acp-1(100) were associated with small spikes. The populations studied differed from one another in the duration and intensity of selective hunting and the increase or decrease in the respective allele frequencies could be explained by selection for large body size, a high number of antler points and against small spikes in yearlings, rather than by genetic drift. Among other morphological characters examined, the length of the main beam was significantly associated with the allele Acp-2(100). In contrast, no associations could be detected between overall heterozygosity and the development or the degree of asymmetry (in paired structures) of any of the morphological traits in question. Although no obvious differences in the overall values of polymorphism or heterozygosity were found between the populations, selective hunting leads towards a change in allele frequencies and eventually to the loss of one or the other rare allele.

Alleles↗
PubMed2005

Estimating visual acuity by character counting using the Snellen visual acuity chart.

PURPOSE: This study examines visual acuity estimation with character counting, which can be used in subjects with nonorganic visual loss. METHODS: The right eyes of 35 healthy subjects were fogged with plus lenses and tested with the Snellen visual acuity chart (Reichert 11180). Visual acuity and counting level were assessed under various degrees of fogging, up to a maximal fogged acuity of 20/200. Counting level was defined as the smallest line that subjects could count the number of characters correctly. For each counting level, the visual acuity that 95% of subjects could see equal to or better than was determined. RESULTS: A counting level of 20/10 estimates (ie 95% chance) a visual acuity equal to or better than 20/30. Counting levels 20/15, 20/20, and 20/25 estimate visual acuities of at least 20/50, 20/80, and 20/80, respectively. Counting levels 20/30-20/60 estimate a visual acuity of at least 20/200. CONCLUSIONS: Character counting appears to be a useful technique of obtaining a rough estimate of visual acuity in subjects unable to be tested by standard methods, such as those with non-organic visual loss.

Adult↗
PubMed2004

Examination of bilayer lipid membranes for 'pin-hole' character.

BLM prepared on electrode substrates by supporting or tethering were tested for 'pin-hole' character, comparing data from cyclic voltammetry (CV), surface plasmon resonance (SPR) and rotating disc electrodes (RDE). 1-hexadecylamine tethered BLMs on SAM modified gold electrodes were compared with BLMs assembled on modified polyHEMA or sol-gel layers. BLM formation followed by SPR showed that the initial phase of the assembly was complete in 5-20 minutes and produced layers of thickness >5 nm, compared with the expected final BLM thickness of approximately 3 nm. The CVs of the K(3)[Fe(CN)(6)] couple were significantly suppressed irrespective of the method of BLM assembly, without major differences emerging for the different methods. However, data from the RDE distinguished the 'pin-hole' character of the different preparations. The data were consistent with incomplete initial (<1 h, SPR estimated BLM thickness >5 nm) vesicle fusion leaving 'pin-holes' of approximately 2 microm (HDA-11-mercaptoundecanoic acid (MUA) tethered BLM) to approximately 3 microm (tetraethylorthosilicate sol-gel supported BLM) followed by a slow maturation (>15 h; impedance spectroscopy estimated thickness approximately 3 nm) and lateral spreading and fusion, resulting in loss of 'pin-hole' character (<1 microm). The BLM could be used in conjunction with potentiometric measurement to observe the incorporation of nystatin into the BLM and the rate of incorporation adjusted according to original permeability of the BLM. The 'pin-hole-free' BLM construction with lowest permeability (TEOS supported, 4 x 10(-10) cm s(-1) compared with HDA-MUA, 3 x 10(-9) cm s(-1)) gave a potentiometric signal independent of bulk ion-concentration across 5 decades change in concentration. Formed on an ion-selective electrode, nystatin incorporation could be followed as a change in potential, over >2 h, whereas the TEOS supported BLM with permeability 1 x 10(-9) cm s(-1) shows nystatin incorporation within 1 h. In this instance, addition of ConA reduced the potential to the same value as prior to nystatin incorporation, consistent with nystatin channel closure.

Biosensing Techniques↗
PubMed1999

Difficulty in writing Japanese semantic characters in a 9-year-old boy with Williams syndrome.

A 9-year-old boy diagnosed as having Williams syndrome was evaluated using psychological test batteries in order to clarify his ability in language and visual cognition. The subject had difficulty in writing some of the Japanese semantic characters (called Kanji) which he could otherwise read and understand. Although he could write the small components of which the Kanji characters were composed, he could not locate these correctly. This phenomenon is considered to be very similar to the difficulty in copying a figure observed clinically. The Kaufmann Assessment Batteries for Children clearly revealed that the boy had difficulty with the sub-test of spatial memory compared to his average score for simultaneous processing. This result is considered to be closely related to the difficulty in copying figures or writing Kanji characters. On the Illinois Test of Psycholinguistic Abilities, the present authors found that the subject's vocabulary was relatively good, although semantic and pragmatic problems remained. Clarifying the strong and weak points of the abilities of such patients will help to determine the most appropriate mode of education for them.

Apraxia, Ideomotor↗
PubMed2004

Reproductive character displacement is not the only possible outcome of reinforcement.

We study the form of the clines in a female mating preference and male display trait using simulations of a hybrid zone. Allopatric populations of two species are connected by demes in a stepping stone arrangement. Results show that reproductive character displacement (a pattern of increased prezygotic isolation in sympatry compared with allopatry) may or may not result when there is reinforcement (defined here as the strengthening of prezygotic isolation as a result of selection against hybrids, relative to the amount of prezygotic isolation present when hybrids are not selected against). Further, reproductive character displacement of the preference may or may not occur when it occurs in the male display. We conclude that the absence of reproductive character displacement is not evidence against the operation of reinforcement.

Animals↗
PubMed2003

The effect of text orientation, visual meridian, and inter-character spacing on word identification in the retinal periphery.

Previous research has demonstrated that the masking effects of flankers about a target in the peripheral retina are not isotropic. Rather, regions of lateral interaction are ellipsoid in shape with the major axis oriented radially along a meridian through the fovea. This finding leads to the counterintuitive prediction that horizontal text positioned to the right of fixation might be read more slowly than similarly positioned text oriented diagonally or vertically. Similarly, vertically oriented text above fixation might be read more slowly than horizontally or diagonally oriented text above fixation. We investigated the effect of text orientation and inter-character spacing on word identification in the retinal periphery. Text was presented by rapid serial visual presentation. Words were centered 3 degrees from fixation along four visual field meridians (VM) (right horizontal, upper-right diagonal, vertical, and upper-left diagonal). Regardless of VM identification, performance was best for horizontal text, declining slightly for orientations between +60 degrees and -60 degrees and declining more quickly for acute orientations. A weak effect of VM was observed for text with normal inter-character spacing. Performance was best for text centered along the horizontal meridian and declined slightly along the other VM. Finally, identification rates increased by approximately 33 words min(-1) with the addition of one character space between adjacent letters. The word-recognition processes are very tolerant of text orientation, exhibiting a modest decline for orientations within +/- 60 of horizontal regardless of VM.

Adult↗
PubMed2003

Experimental test of predation's effect on divergent selection during character displacement in sticklebacks.

Ecological character displacement is common in nature but the mechanisms causing divergence are not well understood. The contributions of ecological interactions other than competition have received little attention. We conducted a pond experiment to explore the contribution of both competition and predation to character divergence in threespine stickleback species. We estimated the strength of divergent selection on a morphologically intermediate target population between competition treatments under two alternate predation treatments. Divergent selection on the target population tended to be stronger in the predator-addition treatment than in the predator-reduction treatment, a difference that approached significance (P = 0.09). This trend occurred even though competition was strongest in the predator-reduction treatment. Overall, the strength of divergent selection was best predicted by stickleback mortality (P = 0.025) being strongest where mortality was highest. These results indicate that predation and other agents of mortality can enhance the rate of change in competition per unit of phenotypic divergence and, thereby, divergent selection, even as they lower the overall strength of competition. In this way, predation and other agents of mortality may facilitate, rather than hinder, character displacement.

Animals↗