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PubMed1990

The Syphaciinae (Oxyuridae, Nematoda) parasitic in rodents and lagomorpha. Numerical taxonomy. Cladistic analysis of evolution.

Two different methods are successively used for the systematic study of the Syphaciinae, a parasitic group of pin-worms specific for the Rodents and Lagomorpha. The statistical method permits to build a "phenetic classification"; the cladistic method permits to build a "phylogenetic classification". The classification finally proposed is principally found on the results of the morphological study of the parasites, but has also in view the integration of all available data concerning the biology, the biogeography and the phylogeny of the hosts.

Animals↗
PubMed1991

Trematodes nervous system.

Three main themes are discussed: 1. Development of the nervous system in the ontogeny of digenetic trematodes; 2. Central and integumentary nervous elements in Cercaria echinata (Echinostomatidae), their evolution in metacercaria and adult; 3. Chaetotaxy and systematics. The structure of the nervous system in digenetic trematodes is based on the occurrence of various neurotransmitters in the nerve tissue. Two major trends in the evolution of the nervous system from cercaria to adult are discerned, one leading to definitive, small number of commissures, established early in the development of the cercaria, the other one leading to formation of great number of commissures completed in the adult. Structure of the nervous system in sporocystic and/or redial generations in various groups of trematodes is compared. Its primitiveness in relation to that of other generations is noted. The central nervous system of Cercaria echinata is pointed out by fixation in glioxylic acid and examination in green light fluorescence. The integumentary sensory elements observed in light microscope, SEM and transmission electron microscope reveal a large variety in structures; propositions are made about their functions. In the corresponding metacercaria, the anterior part of the central nervous system remains unchanged; meanwhile the posterior part increases; several integumentary sensory elements disappear and poorly developed structures, improve; in the adult, transformations are completed. In about 200 various species of cercariae, the sensory receptors are arranged in a conspicuous relation with the nervous system. The study of their number and position; the chaetotaxy is used in systematics and allows very accurate conclusions in specific or infraspecific identifications and in all high taxonomical levels: family, sub-order, super-order. In the same way, miracidial and redial chaetotaxy are used n taxonomy.

Animals↗
PubMedDate not supplied

[Post-therapeutic evolution of patients presenting an immunological suspicion of trypanosomiasis without parasitological proof in support of it (author's transl)].

The authors have recently preconised systematic treatment of every human being who is fluorescent positive. The evolution of antibodies of 26 subjects parasitologically negative and positive only in FAT test is described here after treatment with Arsobal. Statistically the antibodies decrease progressively like antibodies of Sleeping Sickness patients of first period usually did. Therefore it is possible to conclude that immunological suspects who were treated were realy sick and rightly cured.

Congo↗
PubMed1991

Ribosomal DNA: molecular evolution and phylogenetic inference.

Ribosomal DNA (rDNA) sequences have been aligned and compared in a number of living organisms, and this approach has provided a wealth of information about phylogenetic relationships. Studies of rDNA sequences have been used to infer phylogenetic history across a very broad spectrum, from studies among the basal lineages of life to relationships among closely related species and populations. The reasons for the systematic versatility of rDNA include the numerous rates of evolution among different regions of rDNA (both among and within genes), the presence of many copies of most rDNA sequences per genome, and the pattern of concerted evolution that occurs among repeated copies. These features facilitate the analysis of rDNA by direct RNA sequencing, DNA sequencing (either by cloning or amplification), and restriction enzyme methodologies. Constraints imposed by secondary structure of rRNA and concerted evolution need to be considered in phylogenetic analyses, but these constraints do not appear to impede seriously the usefulness of rDNA. An analysis of aligned sequences of the four nuclear and two mitochondrial rRNA genes identified regions of these genes that are likely to be useful to address phylogenetic problems over a wide range of levels of divergence. In general, the small subunit nuclear sequences appear to be best for elucidating Precambrian divergences, the large subunit nuclear sequences for Paleozoic and Mesozoic divergences, and the organellar sequences of both subunits for Cenozoic divergences. Primer sequences were designed for use in amplifying the entire nuclear rDNA array in 15 sections by use of the polymerase chain reaction; these "universal" primers complement previously described primers for the mitochondrial rRNA genes. Pairs of primers can be selected in conjunction with the analysis of divergence of the rRNA genes to address systematic problems throughout the hierarchy of life.

Animals↗
PubMed1987

Interpretation of DNA vibration modes. II--The adenosine and thymidine residues involved in oligonucleotides and polynucleotides.

Normal coordinate analysis of the adenosine and thymidine residues involved in the right- and left-handed conformations of oligonucleotides and polynucleotides has been performed. The valence force field, employed in this work, allowed recently to reproduce the vibrational spectra of 2'-deoxythymidine and 2'-deoxyadenosine. The calculated wavenumbers based on a non-redundant set of internal coordinates have been compared to the Raman and infrared peak positions arising from A, B, C, D and Z conformations, in the 1550-1250 cm-1 and 800-600 cm-1 spectral regions: i.e. characteristic of adenosine and thymidine residues. Moreover, a systematic study has been performed on the evolution of the vibrational wavenumbers as a function of the glycosidic angle (chi) and the sugar pucker conformation.

Adenosine↗
PubMed2026

Reference genomes of Japanese raccoon dog (Nyctereutes viverrinus) and a Japanese red fox (Vulpes vulpes japonica).

We established primary fibroblast cultures from a Japanese raccoon dog (Nyctereutes viverrinus) and a Japanese red fox (Vulpes vulpes japonica) and generated highly contiguous reference genome assemblies using Oxford Nanopore Technologies PromethION long-read sequencing. The Japanese raccoon dog assembly spanned 2.69 Gb in 813 scaffolds, with a scaffold N50 of 52 Mb and a Benchmarking Universal Single-Copy Orthologs (BUSCO) completeness score of 98.2%. The Japanese red fox assembly spanned 2.47 Gb in 903 scaffolds, with a scaffold N50 of 139 Mb and a BUSCO completeness score of 97.5%. Phylogenomic analysis placed the Japanese raccoon dog in a lineage distinct from the continental raccoon dog, supporting its evolutionary differentiation within Nyctereutes. The Japanese red fox formed a distinct lineage within the red fox clade, consistent with its recognized regional differentiation. These genome assemblies and associated fibroblast cultures provide resources for studies of canid systematics, population history, local adaptation, comparative genome evolution, and conservation genetics.

Canidae↗
PubMed2025

Distinct evolutionary trajectories of subgenomic centromeres in polyploid wheat.

BACKGROUND: Centromeres are crucial for precise chromosome segregation and maintaining genome stability during cell division. However, their evolutionary dynamics, particularly in polyploid organisms with complex genomic architectures, remain largely enigmatic. Allopolyploid wheat, with its well-defined hierarchical ploidy series and recent polyploidization history, serves as an excellent model to explore centromere evolution. RESULTS: In this study, we perform a systematic comparative analysis of centromeres in common wheat and its corresponding ancestral species, utilizing the latest comprehensive reference genome assembly available. Our findings reveal that wheat centromeres predominantly consist of five types of centromeric-specific retrotransposon elements (CRWs), with CRW1 and CRW2 being the most prevalent. We identify distinct evolutionary trajectories in the functional centromeres of each subgenome, characterized by variations in copy number, insertion age, and CRW composition. By utilizing CENH3-ChIP data across various ploidy levels, we uncover a series of CRW invasion events that have shaped the evolution of AA subgenome centromeres. Conversely, the evolutionary process of the DD subgenome centromeres involves their expansion from diploid to hexaploid wheat, facilitating adaptation to a larger genomic context. Integration of complete einkorn centromere assemblies and Aegilops tauschii pan-genomes further revealed subgenome-specific centromere evolutionary trajectories. By inclusion of synthetic hexaploid from S2-S3 generations, alongside 2x/6 × natural accessions, we demonstrate that DD subgenome centromere expansion represents a gradual evolutionary process rather than an immediate response to polyploidization. CONCLUSIONS: Our study provides a comprehensive landscape of centromere adaptation, evolution, and maturation, along with insights into how retrotransposon invasions drive centromere evolution in polyploid wheat.

Centromere↗
PubMed1985

Evolutionary trends of the histological pattern in the teeth of Edentata (Xenarthra).

In a comparative study of the dental structure of Edentata, the central tissue was identified as a modified orthodentine, except in the Glyptodontidae where an osteodentine was found. Some evolutionary trends of the tissues in these teeth may have been related with the extinction of ground sloths. Comparative studies of the tissues in mammalian teeth seem to be good tests for systematics.

Animals↗
PubMed1989

Interactive analysis of phylogeny and character evolution using the computer program MacClade.

Computer programs for phylogenetic analysis have been important tools in systematics and evolutionary biology, but most have been designed primarily for the reconstruction of phylogenetic trees and not the interpretation of patterns of character evolution. Described here is the computer program MacClade, designed for interactive analysis of character evolution and phylogeny. For a given tree and a matrix of character data, MacClade displays its reconstruction of character evolution by shading the branches of the tree to indicate ancestral states. Trees can be manipulated for instance by picking up and moving branches. Assumptions underlying the reconstruction of character evolution can be varied extensively. With these manipulations and MacClade's graphical feedback, one can explore the relationships among phylogenetic trees, character data, assumptions and interpretations of character evolution. MacClade has extensive facilities for editing data, displaying various summaries of character evolution in charts and diagrams, and printing.

Animals↗
PubMed2026

SARS-CoV-2 intra-host variation shows evidence of transmission and convergent evolution in a university surveillance cohort.

Monitoring and understanding the transmission and evolution of SARS-CoV-2 remains a significant public health priority. Within-host genetic variation provides insight into viral evolution during infection and may help infer transmission events. In this study, we analysed intra-host variation in SARS-CoV-2 genome sequences from Boston University's testing mandate. Focusing on intra-host single nucleotide variants (iSNVs), we inferred transmission events and assessed the selective forces shaping within-host viral evolution. To minimize false-positive iSNVs resulting from systematic biases, we implemented stringent data filtering and developed a heuristic to exclude contamination-derived artefacts arising from batched sequencing. We find that intra-host variation is limited and infrequently transmitted during acute infections, suggesting that shared iSNVs serve as highly specific but insensitive markers of transmission. We also observed incomplete purifying selection shaping within-host diversity, with the loci most affected changing among variants of concern. Finally, we identified a highly recurrent iSNV (G11083T) which may represent a site of positive selection. Our results highlight that within-host variation provides insight into within-host pathogen evolution, in spite of its limited use in genomic epidemiology.

SARS-CoV-2↗
PubMed1990

Classical taxonomy of mosquitoes--a memorial to John N. Belkin.

The major contributions of John N. Belkin to the field of mosquito systematics are noted. Hallmarks of his publications are presented and his hypotheses about the evolution, speciation, competition, distribution and classification of mosquitoes are summarized. The current status of the field of mosquito systematics is examined. It is argued that mosquito systematics is still largely at the alpha taxonomy level, that at best only 25-50% of mosquito species are known, and that we have not even begun to develop a natural classification for the Culicidae. It is concluded that there will be little improvement in the status of mosquito taxonomy unless there is increased support for systematics.

Animals↗
PubMed1975

[The cardiovascular manifestations of Paget's disease].

After reviewing the old ideas (peripheral syndrome and cardiac insufficiency at high outputs) and more recent ideas (arterial and intracardiac vascular calcification), the authors report their experiences based on the study of the histories of 150 patients suffering from Paget's disease followed for several years. First they emphasize the frequent latency of cardiac manifestations looked for systematically by means of the electrocardiogram particularly during evolutive stages of the disease. Electrocardiographic disturbances were observed 91 times and included 43 cases of conduction disorders and 48 of repolarization disorders; their distribution was studied as a function of various inherent parameters, of the patient (age and sex) and of the disease (its evolutive character and its degree of diffusion). On the basis of the anti-arythmic power of calcitonin found during experiments and obtained excellent results three times. Finally the place of cardiovascular manifestations in the pathogenic hypotheses and nosology of Paget's disease is discussed.

Adult↗
PubMed1991

[A developmental anomaly of Meckel's cartilage].

An atypical evolution of the mandibular cartilage was recorded in systematic dissections of the neck in the Anatomy Laboratory. This anomaly led to the formation of a supernumerary bony fragment in the concavity of the lower edge of the mandibular arch, with a slight adhesion thereto. This observation is reported by the authors after a recapitulation of the embryology.

Aged↗
PubMed1977

[Psychology of relationships as a theoretical concept in medical psychology and psychotherapy].

The theoretical concept called "psychology of relations" (A. F. Lazursky, V. N. Myasishchev) is offered as the basis for a study of a patient's personality and psychotherapy. The author stresses ideological relationship of psychology of relations with phylosophy of dialectical materialism and I. P. Pavlov's studies about conditioned reflexes, its relationship with clinical psychoneurology, its direction to a study of the personality and adherence to primacy of consciousness over unconciousness. The perspectiveness of the evolutionally ontogenetic approach to the analysis of the system of relations and necessity to elaborate working systematizations determined by the research purpose, is stated.

Biological Evolution↗