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PubMed2026

Ultrastructural Insights Into the Reproductive Anatomy and Eggs of Cotton Pink Bollworm, Pectinophora gossypiella Saunders (Lepidoptera: Gelechiidae).

The pink bollworm, Pectinophora gossypiella Saunders is a major pest of cotton, notorious for its high reproductive potential and rapid evolution of resistance to Bacillus thuringiensis (Bt) toxins. Despite its economic significance, detailed knowledge of its reproductive anatomy and egg ultrastructure has remained limited, constraining the development of advanced molecular control strategies such as CRISPR/Cas9-based genome editing. The present study provides the first comprehensive characterization of the reproductive system and egg surface morphology of P. gossypiella using stereomicroscopy and scanning electron microscopy (SEM) techniques. The male reproductive system consists of fused, bean-shaped testes, seminal vesicles, duplex and simplex ejaculatory ducts, and paired accessory glands. The female reproductive system comprises paired ovaries with four polytrophic ovarioles per ovary, lateral and common oviducts, accessory glands, corpus bursae, and spermathecal glands. Eggs are oval, dorsoventrally flattened, exhibit a reticulated chorion with distinct micropylar and aeropylar regions. SEM images revealed 6-9 rosette cells encircling a circular micropylar plate, 14-19 first order and 17-23 s order ribs, and 250-291 polygonal surface cells. The structural features of P. gossypiella eggs reveal key sites for sperm entry, aeropylar respiration, and candidate zones for microinjection in gene editing applications. These findings establish a morphological baseline critical for optimizing embryo manipulation and ribonucleoprotein (RNP) delivery in lepidopteran genome editing. This study represents a pioneering effort to integrate classical egg morphology with molecular entomology, thereby advancing precision genetic interventions aimed at resistance management and population suppression in P. gossypiella.

Animals↗
PubMed2006

Insertion sequences in prokaryotic genomes.

Insertion sequences (ISs) are small DNA segments that are often capable of moving neighbouring genes. Over 1500 different ISs have been identified to date. They can have large and spectacular effects in shaping and reshuffling the bacterial genome. Recent studies have provided dramatic examples of such IS activity, including massive IS expansion during the emergence of some pathogenic bacterial species and the intimate involvement of ISs in assembling genes into complex plasmid structures. However, a global understanding of their impact on bacterial genomes requires detailed knowledge of their distribution across the eubacterial and archaeal kingdoms, understanding their partition between chromosomes and extra-chromosomal elements (e.g. plasmids and viruses) and the factors which influence this, and appreciation of the different transposition mechanisms in action, the target preferences and the host factors that influence transposition. In addition, defective (non- autonomous) elements, which can be complemented by related active elements in the same cell, are often overlooked in genome annotations but also contribute to the evolution of genome organisation.

Bacteria↗
PubMed1990

A mechanism of formation of protein-free regions in the red cell membrane: the rupture of the membrane skeleton.

The process of rupture and redistribution of the red cell membrane skeleton is analyzed theoretically. Following the emergence of the rupture the spectrin-actin network is redistributed on the cytoplasmic surface of the membrane bilayer. Due to the interaction of the membrane skeleton and integral proteins the redistribution of the spectrin-actin network leads to the release of purely lipid regions of the membrane. The scale of the protein redistribution caused by the rupture of the membrane skeleton and the size of the lipid domains produced depend on the shape of the membrane and the value of the electrical interaction of the membrane proteins. The lipid domains occurring as a result of the rupture and relaxation of the spectrinactin network can spontaneously increase or decrease its area. The criteria determining the conditions which result in the system's evolutions leading to the domain growth have been obtained. The character of the evolution is determined by the shape of the membrane region in which the rupture occurs as well as the relation between the effective linear tension of the rupture boundary and the modulus of elasticity of the spectrin-actin network.

Animals↗
PubMed1978

The evolution of 5S RNA secondary structures.

We have applied the Pipas-McMahon algorithm based on free energy calculations to the search for a 5S RNA base-pair structure common to all known sequences. We find that a 'Y' shaped model is consistently among the structures having the lowest free energy using 5S RNA sequences from either eukaryotic or prokaryotic sources. Compaison of this 'Y' structure with models which have recently been proposed show these models to be remarkably similar, and the minor differences are explicable based on the technique used to obtain the model. That prokaryotic and eukaryotic 5S RNA can adopt a similar secondary structure is strong support for its resistance to change during evolution.

Animals↗
PubMed2002

Robustness, flexibility, and the role of lateral inhibition in the neurogenic network.

BACKGROUND: Many gene networks used by developing organisms have been conserved over long periods of evolutionary time. Why is that? We showed previously that a model of the segment polarity network in Drosophila is robust to parameter variation and is likely to act as a semiautonomous patterning module. Is this true of other networks as well? RESULTS: We present a model of the core neurogenic network in Drosophila. Our model exhibits at least three related pattern-resolving behaviors that the real neurogenic network accomplishes during embryogenesis in Drosophila. Furthermore, we find that it exhibits these behaviors across a wide range of parameter values, with most of its parameters able to vary more than an order of magnitude while it still successfully forms our test patterns. With a single set of parameters, different initial conditions (prepatterns) can select between different behaviors in the network's repertoire. We introduce two new measures for quantifying network robustness that mimic recombination and allelic divergence and use these to reveal the shape of the domain in the parameter space in which the model functions. We show that lateral inhibition yields robustness to changes in prepatterns and suggest a reconciliation of two divergent sets of experimental results. Finally, we show that, for this model, robustness confers functional flexibility. CONCLUSIONS: The neurogenic network is robust to changes in parameter values, which gives it the flexibility to make new patterns. Our model also offers a possible resolution of a debate on the role of lateral inhibition in cell fate specification.

Alleles↗
PubMed1998

Characterization of cytoplasmic secretory granules (PSG), in prostatic epithelium and their transformation-induced loss in dysplasia and adenocarcinoma.

Cytoplasmic clarity is a histological feature of normal prostatic secretory cells, but in this study, tissue fixation in strong (>2.5%) glutaraldehyde dramatically altered cytological staining. Secretory cytoplasm appeared red and granular on routine stains because of myriad intensely staining eosinophilic granules (PSG). Immunostaining for prostate-specific antigen (PSA) and prostatic acid phosphatase (PAP) showed their exclusive localization to the PSG. Electron microscopy confirmed these findings and also showed that after fixation in many agents, including formaldehyde, PSG appeared empty, accounting for the artefactual "clear cell" appearance on light microscopy. PSG were most densely concentrated apically in a bud-shaped luminal compartment in which cytokeratin was selectively absent. Normal exocrine secretion was visualized as detachment of apocrine buds or their in situ disintegration. Distinctively in dysplasia and almost all carcinomas, PSG were rare to absent, and proteases were free in the cytoplasm, often concentrated beneath the apical membrane. The apocrine compartment was absent, with no observed secretory mechanism. Tumor cells had dark amphiphilic cytoplasm after all fixatives. This provided a reliable method of distinguishing malignant from benign glands in tissues fixed in strong glutaraldehyde. Clear cell carcinomas, whose cytoplasm mimicked routinely fixed normal secretory cells, surprisingly had almost no PSG. Instead, their "granules" were lipid-filled vacuoles reflecting a secretory pathway not seen in normal cells, dysplasia, or the common "dark cell" carcinomas. These observations may define two distinctive biological pathways of prostate cancer evolution and may facilitate diagnostic decisions on needle biopsy samples.

Acid Phosphatase↗
PubMed1986

Species differences in electric organs of mormyrids: substrates for species-typical electric organ discharge waveforms.

The organization of electric organs is described for the mormyrid fishes from Africa. The electric organ's spike-generating cells or electrocytes are wafer-shaped cells with a special geometry that relates to the number of phases and polarity of their pulsatile electric organ discharge (EOD) waveform. Six "families" of electrocytes are recognized on the basis of cell geometry. Each family includes species with EODs of similar polarity and phase number. Despite such similarities, there are still dramatic species differences in EOD waveforms for a given family that may further depend on specialized features of the electrocyte's excitable membranes. It is each species' particular electrocyte "profile" that must underlie the development of species-specific and hormone-dependent sex differences in the EOD waveforms.

Animals↗
PubMed2005

Differentiation and diversification of follicular cells in polytrophic ovaries of crane flies (Diptera: Nematocera: Tipulomorpha and Trichoceridae).

To gain insight into the evolution of differentiation pathways that are involved in the follicular cells' morphogenesis in dipteran ovaries we have undertaken the comparative morphological analysis of the follicular cell behavior in crane flies, representatives of more ancestral nematocerous flies. This analysis revealed that initially the organization of the follicular epithelium in the species under study shows significant similarities to that reported in the ovaries of true flies (Brachycera), indicating that the ancestors of dipterans must have evolved a common and specific system of the early patterning of their follicular epithelium. On the other hand, in contrast to Drosophila and other advanced brachycerans, the follicular cells in the studied nematoceran ovaries do not exhibit any migratory activity. Instead, they were found to change their relative position but only within the epithelial layer. These "translocations" appeared to depend merely on cell shape changes. Although the "immobility" of the follicular cells in the ovaries of crane flies results in the lower number of their specialized subgroups when compared with the true flies, the functional homology between particular subsets of follicular cells can be postulated. We suggest that the anterior polar cells and the micropyle forming anterior terminal follicular cells in crane fly ovaries have their counterparts in the brachyceran anterior polar cells and border cells, respectively.

Animals↗
PubMed1986

Origin and evolution of the transcribed repeated sequences of the Y chromosome lampbrush loops of Drosophila hydei.

The molecular evolution and patterns of conservation of clones from four Y chromosome lampbrush loops of Drosophila hydei were investigated. Each loop contains a discrete family of transcribed repeats that are only slightly conserved even in the hydei subgroup species. Sequencing of clones from the four D. hydei loops indicates that all transcribed repeats evolved from A+T-rich elements of the genome. Evidence is presented that suggests a Y-specific family evolved as a result of the transposition of repeated sequences from an autosomal site to the Y chromosome with the concomitant acquisition of transcriptional activity and loss of non-Y sequences. The results support a structural role for the loops in shaping a spermatocyte-specific nuclear organization. Transcribed heterochomatic sequences could play a similar role in nuclear organization in many cell types.

Journal Article↗
PubMed2000

Time-resolved infrared spectroscopy of molecule/binding site reorientation during ferroelectric liquid crystal electro-optic switching

Polarized Fourier transform infrared (IR) absorption is used to probe molecular conformation in a ferroelectric liquid crystal during the large-scale collective reorientation induced by external applied electric field. Spectra of planar-aligned cells of the ferroelectric liquid crystal (FLC) W314 ((S)-4(')-(decyloxy)4-[(1-methylheptyl)oxy]-2-nitrophenyl-[1, 1'-biphenyl]-4-carboxylic acid ester) are measured as functions of IR polarizer orientation and time following the reversal of the electric field applied to the FLC. The time evolution of the dichroism of the absorbance due to the specific molecular vibration modes, particularly from the biphenyl core and alkyl tail, is observed. Static IR dichroism experiments show a W314 IR dichroism structure in which the principal axis of the dielectric tensor from molecular core vibrations are tilted further from the smectic layer normal than those of the tail. This structure indicates that the effective binding site in which the molecules are confined in the Sm-C phase has, on average, a "zig-zag" shape. The dynamic experiments show that this zig-zag binding site structure is rigidly maintained while the molecular axis rotates about the layer normal during field-induced switching.

Journal Article↗
PubMed1986

Evolutionary trends in sperm structure.

In the marine invertebrates which practise external fertilization, the spermatozoon is a flagellate cell, possessing an acrosomal complex made up of acrosome and perforatorium. In the animal phyla which adapted to land after having achieved internal fertilization the spermatozoon has acquired an elongated shape and develops accessory cytoskeletal organelles in the tail. In the highest forms, the flagellum seems to have become too long for perfect motility; in such a condition, aberrant axonemal patterns can appear and aflagellate spermatozoa can also be found. At the apex of the terrestrial phyla, alternative motile apparatuses have been achieved and also the acrosomal complex varies, according to the different structures of egg envelopes.

Animals↗
PubMed2004

Stochastic modeling of the tumor volume assessment and growth patterns in hepatocellular carcinoma.

The growth pattern of hepatocellular carcinoma (HCC) arising from cirrhosis is variable and depends on the degree of differentiation and vascularization. Because growth is not constant in the natural history of HCC, prediction of subsequent growth rate based on tumor volume doubling time and correlation with histological and ultrasonographical characteristics at the moment of initial diagnosis are usually unreliable. The aim of our study was to assess the growth patterns of HCC with the aid of stochastic modeling. Thus, we included in our study 27 patients with histologically proven HCC, which had multiple (more than three)follow-up ultrasound studies in a six months interval. The patients did not receive any treatment during the observation period. HCC was visualized by computer aided ultrasound imaging, obtaining both the primary size quantification and the edge-detection enhancement. By a bi-cubic B-spline interpolation of points on the edges (3-D Bezier approximation) we approximated the surfaces shapes, and using the hit or miss Monte Carlo method we accurately estimate the tumor volume. Starting from the previous tumor volumes time series recorded during the first six months of evolution we applied both a linear, exponential and logarithmic smoothing to forecast the future size of the HCC tumor in the next six months. Our conclusion was that a dynamic forecasting model of HCC volumes could be very accurate for the assessment of tumor volume doubling time usually obtained by two discrete volume measurements of the tumor.

Adult↗
PubMed2002

Regulation and chance in the ontogeny of B and T cell antigen receptor repertoires.

The adaptive immune system has to economically generate a large array of T and B cell antigen receptors (T cell receptors [TCRs], B cell receptors [BCRs]) that eliminate both longstanding and novel antigens from the host while preventing the production of deleterious (e.g., autoreactive) antigen receptors. Our studies focus on the mechanisms that shape the development of these antigen receptor repertoires during human ontogeny. The key to BCR and TCR diversity is the third complementarity determining region (CDR3) of the variable domain, which in the immunoglobulin heavy chain and TCR beta chain, is created by the junction between the variable, diversity, and joining gene segments. The CDR3 diversity is constrained by overrepresentation of gene segments and lack of N regions during the first trimester of gestation and then increases exponentially during ontogeny until it reaches adult levels months after birth. This process parallels, and may contribute to, the stepwise acquisition of the ability to respond to specific antigens. Recent studies indicate that maturation of the CDR3 repertoire is not accelerated by premature exposition to extrauterine antigen and thus appears to follow a strictly developmentally regulated program whose pacemaker(s) is still unknown.

Antigenic Variation↗
PubMed2003

Fermentation of glycolate by a pure culture of a strictly anaerobic gram-positive bacterium belonging to the family Lachnospiraceae.

The component bacteria of a three-membered mixed culture able to ferment glycolate to acetate, propionate and CO(2) were isolated in pure culture. All three strains were strict anaerobes that, on the basis of comparative 16S rRNA gene sequence analysis, belonged to the order Clostridiales in the phylum Firmicutes (low G+C gram-positive bacteria). Two of the strains were not involved in glycolate metabolism. The third, the glycolate-fermenting strain 19gly4 (DSM 11261), was related to members of the family Lachnospiraceae. The cells of strain 19gly4 were oval- to lemon-shaped, 0.85 microm long and 0.65 microm in diameter, occurring singly, in pairs, or in chains of up to 30 cells. Strain 19gly4 fermented glycolate or fumarate to acetate, succinate, and CO(2). Hydrogen was not formed, and strain 19gly4 was able to grow on glycolate in pure culture without any syntrophic hydrogen transfer and without the use of an external electron acceptor. There was no evidence for homoacetogenic metabolism. This bacterium therefore differs in metabolism from previously reported glycolate-utilising anaerobes.

Anaerobiosis↗
PubMed2025

The evolution of hominin bipedalism in two steps.

Bipedalism is a human-defining trait1-3. It is made possible by the familiar, bowl-shaped pelvis, whose short, wide iliac blades curve along the sides of the body to stabilize walking and support internal organs and a large-brained, broad-shouldered baby4-6. The ilium changes compared with living primates are an evolutionary novelty7. However, how this evolution came about remains unknown. Here, using a multifaceted histological, comparative genomic and functional genomic approach, we identified the developmental bases of the morphogenetic shifts in the human pelvis that made bipedalism possible. First, we observe that the human ilium cartilage growth plate underwent a heterotopic shift, residing perpendicular to the orientation present in other primate (and mouse) ilia. Second, we observe heterochronic and heterotopic shifts in ossification that are unlike those in non-human primate ilia or human long bones. Ossification initiates posteriorly, resides externally with fibroblast (and perichondral) cells contributing to osteoblasts, and is delayed compared with other bones in humans and with primate ilia. Underlying these two shifts are regulatory changes in an integrated chondrocyte-perichondral-osteoblast pathway, involving complex hierarchical interactions between SOX9-ZNF521-PTH1R and RUNX2-FOXP1/2. These innovations facilitated further growth of the human pelvis and the unique formation of the ilium among primates.

Animals↗
PubMed1999

Devescovinid trichomonad with axostyle-based rotary motor ("Rubberneckia"): taxonomic assignment as Caduceia versatilis sp. nov.

An amitochondriate trichomonad cell of the family Devescovinidae (Class Parabasalia), helped demonstrate the fluid model of lipoprotein cell membranes. This wood-ingesting symbiont in the hindgut of the dry wood-eating termite Cryptotermes cavifrons is informally known to cell biologists as "Rubberneckia". As the microtubular axo-style complex generates force causing clockwise movement of the entire anterior portion of the cell at the shear zone the protist displays "head" rotation. Studies by phase contrast and videomicroscopy of live cells, of whole mounts by scanning, and thin sections by transmission electron microscopy extend the observations of Tamm and Tamm [24-26] and Tamm [19-23]. Habitat, cell shape, size, nuclear features, parabasal apparatus and other morphological details permit the assignment of "Rubberneckia" to Kirby's cosmopolitan genus Caduceia. This large-sized devescovinid has distinctive parabasal gyres, an axostylar rotary, motor, and regularly-associated nonflagellated, fusiform and flagellated rod epibiotic surface bacteria. In addition to regularly aligned epibionts intranuclear and endocytoplasmic bacteria are abundant and hydrogenosomes are Present. "Rubberneckia" is compared here to the other seven species of Caduceia. Since it is clearly sufficiently distinctive to warrant new species status, we named it C. versatilis.

Animals↗
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↗
PubMed2005

Myelodysplastic syndromes: clinicopathologic features, pathobiology, and molecular pathogenesis.

CONTEXT: Myelodysplastic syndromes (MDSs) are clonal stem cell diseases characterized by ineffective hematopoiesis, multilineage dysplasia, and peripheral cytopenias with normocellular or hypercellular marrow. They represent a heterogeneous group of disorders with a varied spectrum of clinical, morphologic, biologic, and genetic characteristics. This heterogeneity in disease characterization has led to evolving classification systems, developing prognostic models, and continuing research efforts to elucidate its pathobiology and pathogenesis. OBJECTIVE: To summarize updated information and provide a general overview of the clinicopathologic features, pathobiology, and cytogenetic and molecular pathogenesis of MDSs. DATA SOURCES: Relevant articles indexed in PubMed (National Library of Medicine) between 1982 and 2005 and reference medical texts. CONCLUSIONS: Although MDSs remain a relatively poorly defined disease entity, recent advancements in cytogenetic and molecular studies have significantly contributed to our present knowledge of MDSs. Novel strategies for studying the pathogenesis and evolution of MDSs continue to shape our understanding of this disease and guide our approaches to diagnosis and treatment.

Cytogenetics↗