Growth Morphology Research Articles

Multidisciplinary approach to postmortem diagnostics

BACKGROUND: The technique that allows detecting various pathologies and clearly identifying the cause of death and other associated diseases without disturbing the integrity of the skin refers to postmortem radiological diagnostics and is called virtopsy. The number of autopsies decreases worldwide, which creates the need to use alternative non-invasive methods, including virtopsy. The main method of postmortem radiology is multislice computed tomography (CT), with its advantages including high sensitivity to bone pathology. Postmortem radiological diagnostics allow supplementing the classical autopsy. This multidisciplinary approach helps visualize a wide variety of pathologies and assist the pathologist in the diagnostic search.
 AIM: To assess the possibility of applying radiological diagnostic methods in the pathological anatomical practice and features of non-invasive autopsy (virtopsy) and its differences from the classical autopsy.
 METHODS: The archival material including macro preparations of two lower limbs with tumor-like masses of unclear genesis (the upper third of the femur and the calcaneal tuber) was used. The biomaterial was previously encased in a specially treated gelatin medium, which ensured its preservation and left parts of the CT scanner intact. Multislice CT was used for radiological assessment of the preparations. From the primary CT sequences obtained, scans with the best visualization in the bone and soft tissue windows were selected, and three-dimensional (3D) reconstruction was applied. Scans and 3D reconstructions of images of tumor-like masses of the heel and thigh bones were obtained. Interpretation of the borders of the mass, characteristics of morphology and possible source of growth of the neoplasm allowed assuming a malignant nature of the tumor, suggesting its bone origin. Further histologic examination in both cases confirmed the neoplasm (osteogenic sarcoma).
 RESULTS: CT scans and 3D reconstructions of images of tumour-like masses in the heel and femur were obtained. The interpretation of the boundaries of the mass, the morphological characteristics and the possible source of growth of the neoplasm suggested a malignant nature of the tumour, suggesting a bony origin. Further histological evaluation in both cases confirmed the nature of the neoplasm (osteogenic sarcoma).
 CONCLUSIONS: The use of postmortem radiological diagnostic elements provides a sufficiently accurate verification of the nature of some pathologies. However, the absence of tissue damage and disturbances of intact topographic characteristics play not the least role in the postmortem diagnosis. In contrast to autopsy, this technique allows to return to the original appearance of the structures examined and, if necessary, start the diagnostic search anew. Moreover, specialists from other regions can be remotely involved by sending the data of CT scanning.

Activity competition of catalysts and supports materials on the growth of carbon nanotubes with ZrO2/Fe catalyst

Activity competition commonly exist when using multiple catalyst particles for growing carbon nanotubes (CNTs), and the diverse catalysts can compete with the carbon source and affect the growth kinetics and morphology of the nanotubes. However, the existed problem is that whether the support materials themselves also can engage in activity competition with the catalysts, and how this may impact the growth of CNTs. Here, we investigated the influence of hypoactive ZrO2 support material and hyperactive ZrO2/Fe catalysts on the growth of CNTs, and the activity competition relationship between the support and the catalysts. ZrO2/Fe catalysts were prepared via a facile hydrothermal method, and employed both CH4 and C2H5OH as carbon sources for growing CNTs. It is interesting that single-walled carbon nanotubes (SWCNTs) were grown by utilizing CH4 as carbon source, and multi-walled carbon nanotubes (MWCNTs) were synthesized for the use of C2H5OH as carbon source. A combination of experimental data and density functional theory simulations was able to reveal the underlying activity competition mechanism between hyperactive catalysts and hypoactive supports. It would provide new insight into the growth mechanisms of CNTs, and provide new ideas for the rational design and controlled growth of CNTs.

Impact of osmotic stress on production, morphology, and fitness of Beauveria bassiana blastospores.

Beauveria bassiana is a cosmopolitan entomopathogenic fungus that can infect over 1000 insect species. During growth inside the host, B. bassiana transitions from hyphal to yeast-like unicellular growth as blastospores. Blastospores are well suited as an active ingredient in biopesticides due to their ease of production by liquid fermentation. Herein, we investigated the impact of hyperosmotic growth environments mediated by ionic and non-ionic osmolytes on two strains of B. bassiana (ESALQ1432 and GHA) relevant to growth morphology, blastospore production, desiccation tolerance, and insecticidal activity. Polyethylene glycol (PEG200) increased osmotic pressure in submerged cultures leading to decreased blastospore size but higher blastospore yields for one strain. Morphologically, decreased blastospore size was linked to increased osmotic pressure. However, smaller blastospores from PEG200 supplemented cultures after air-drying exhibited delayed germination. Ionic osmolytes (NaCl and KCl) generated the same osmotic pressure (2.5-2.7MPa) as 20% glucose and boosted blastospore yields (> 2.0 × 109 blastospores mL-1). Fermentation performed in a bench-scale bioreactor consistently promoted high blastospore yields when using NaCl (2.5MPa) amended media within 3days. Mealworm larvae (Tenebrio molitor) were similarly susceptible to NaCl-grown blastospores and aerial conidia in a dose-time-dependent manner. Collectively, these results demonstrate the use of hyperosmotic liquid culture media in triggering enhanced yeast-like growth by B. bassiana. Understanding the role of osmotic pressure on blastospore formation and fitness will hasten the development of viable commercial fungal biopesticides. KEY POINTS: • Osmotic pressure plays a critical role in submerged fermentation of B. bassiana. • Ionic/non-ionic osmolytes greatly impact blastospore morphology, fitness, and yield. • Desiccation tolerance and bioefficacy of blastospores are affected by the osmolyte.

Metal-induced lateral crystallization of germanium thin films

Recent advances in polycrystalline Ge layers formed through solid-phase crystallization have demonstrated carrier mobilities superior to those of single-crystal Si. In this study, we thoroughly examined the phenomenon of metal-induced lateral crystallization in Ge, a topic that had garnered significant attention in Si research and had shown promise in improving the performance of thin-film transistors. Of the 24 metals tested (Au, In, Bi, Pb, Ga, Ag, Al, Sn, Zn, Sb, Fe, Nb, Mg, Mn, Co, Cr, Mo, Zr, Cu, Ni, Pd, Ta, Ti, and W), 20 were found to promote the low-temperature (<400 °C) lateral growth of Ge layers on glass. Based on the reaction type (eutectic or compound), reaction temperatures, diffusion coefficients, and domain matching analyzed using a materials informatics method, the growth morphology was categorized into three types: alloy, dendrite, and uniform. The knowledge of metal-induced growth obtained in this study has broad implications for a variety of materials and holds potential for developing the next generation thin-film devices with common and inexpensive substrates.

Dislocation‐Induced Structural and Luminescence Degradation in InAs Quantum Dot Emitters on Silicon

This study probes the extent to which dislocations reduce carrier lifetimes and alter growth morphology and luminescence in InAs quantum dots (QD) grown on silicon. These heterostructures are key ingredients to achieving a highly reliable monolithically integrated light source on silicon necessary for photonic‐integrated circuits. Around 20%–30% shorter carrier lifetimes are found at spatially resolved individual dislocations at room temperature using time‐resolved cathodoluminescence spectroscopy, highlighting the strong nonradiative impact of dislocations even against the three‐dimensional confinement of QDs. Beyond these direct effects of increased nonradiative recombination, it is found that misfit dislocations in the defect filter layers employed during III–V/Si growth alter the QD growth environment to induce a crosshatch‐like variation in QD emission color and intensity when the filter layer is positioned sufficiently close to the QD emitter layer. Sessile threading dislocations generate even more egregious hillock defects that also reduce emission intensities by altering layer thicknesses, as measured by transmission electron microscopy and atom probe tomography. This work presents a more complete picture of the impacts of dislocations relevant to the development of light sources for scalable silicon photonic integrated circuits.

The Interaction Between Interface Morphology of Particles with Anisotropic Effect of Interface Kinetics in an Alloy Melt

AbstractThe conventional theory of crystal growth presents an irreversible outward increase of the crystal size through solute deposition on the nuclei; however, the asymptotic solution of the dynamics model of the particle reveals that the crystal growth undergoes a locally reversible inward growth process in the early stage of crystal growth. Immediately after nucleation, some parts of the interface first grow inward through solute rejection along certain crystal orientations from the interface of nucleation, while the other parts of the interface grow outward through solute deposition along other crystal orientations. Until the inward growth attains a certain distance, the interface grows outward along each crystal orientation. This growth behavior is attributed to the interaction between interface morphology of particles with the anisotropic effect of interface kinetics. Through a systematic variation of the anisotropy parameters, the particle exhibits a continuous transition from one growth morphology to other growth morphologies. During the morphological transition process, as initial concentration increases, the growth of the particle is inhibited in the preferred growth directions, whereas it is facilitated in other growth directions. As a result, the interface morphologies of the particle with different petal‐shaped morphologies in the early stage of crystal growth are formed.

AlGaN HEMT Structures Grown on Miscut Si(111) Wafers.

A complex study was performed on a set of AlGaN/GaN high-electron-mobility transistor structures grown by metalorganic vapor phase epitaxy on miscut Si(111) wafers with a highly resistive epitaxial Si layer to investigate the influence of substrate miscut on their properties. The results showed that wafer misorientation had an influence on the strain evolution during the growth and surface morphology, and could have a strong impact on the mobility of 2D electron gas, with a weak optimum at 0.5° miscut angle. A numerical analysis revealed that the interface roughness was a main parameter responsible for the variation in electron mobility.

Growth Instability of 2D Materials on Non-Euclidean Surfaces.

Chemical growth of two-dimensional (2D) materials with controlled morphology is critical to bring their tantalizing properties to fruition. However, the growth must be on a substrate, which involves either intrinsic or intentionally introduced undulation, at a scale significantly larger than the materials thickness. Recent theory and experiments showed that 2D materials grown on a curved feature on substrates can incur a variety of topological defects and grain boundaries. Using a Monte Carlo method, we herein show that 2D materials growing on periodically undulated substrates with nonzero Gaussian curvature of practical relevance follow three distinct modes: defect-free conformal, defect-free suspension and defective conformal modes. The growth on the non-Euclidean surface can accumulate tensile stress that gradually lifts the materials from substrates and progressively turns the conformal mode into a suspension mode with increasing the undulation amplitude. Further enhancing the undulation can trigger Asaro-Tiller-Grinfield growth instability in the materials, manifested as discretely distributed topological defects due to strong stress concentration. We rationalize these results by model analyses and establish a "phase" diagram for guiding the control of growth morphology via substrate patterning. The undulation-induced suspension of 2D materials can help understand the formation of overlapping grain boundaries, spotted quite often in experiments, and guide how to avoid them.

Prediction of Ethanol-Mediated Growth Morphology of Ammonium Dinitramide/Pyrazine-1,4-Dioxide Cocrystal at Different Temperatures.

The crystal morphology of high energetic materials plays a crucial role in aspects of their safety performance such as impact sensitivity. In order to reveal the crystal morphology of ammonium dinitramide/pyrazine-1,4-dioxide (ADN/PDO) cocrystal at different temperatures, the modified attachment energy model (MAE) was used at 298, 303, 308, and 313 K to predict the morphology of the ADN/PDO cocrystal under vacuum and ethanol. The results showed that under vacuum conditions, five growth planes of the ADN/PDO cocrystal were given, which were (1 0 0), (0 1 1), (1 1 0), (1 1 -1), and (2 0 -2). Among them, the ratios of the (1 0 0) and (0 1 1) planes were 40.744% and 26.208%, respectively. In the (0 1 1) crystal plane, the value of S was 1.513. The (0 1 1) crystal plane was more conducive to the adsorption of ethanol molecules. The order of binding energy between the ADN/PDO cocrystal and ethanol solvent was (0 1 1) > (1 1 -1) > (2 0 -2) > (1 1 0) > (1 0 0). The radial distribution function analysis revealed that there were hydrogen bonds between the ethanol and the ADN cations, van der Waals interactions with the ADN anions. As the temperature increased, the aspect ratio of the ADN/PDO cocrystal was reduced, making the crystal more spherical, which helped to further reduce the sensitivity of this explosive.

Structure Regulation of Sodium Ion on Nanosilica Growth Visualized Using 29Si Nuclear Magnetic Resonance Spectroscopy

Understanding the action mechanism of sodium ions in sodium silicate solutions is necessary for the synthesis of nanosilica. The microstructure of sodium silicate solutions with SiO2:Na2O ratios ranging from 2 to 4 was characterized by 29Si nuclear magnetic resonance spectroscopy, and the magnetic shielding tensor of the nuclear magnetic field was calculated using the density functional theory. Sodium ions contribute significantly to the magnetic shielding tensor, thereby playing a key role in the structural evolution of sodium silicate solution species. Wave function analysis was used to further study the mechanism of action of sodium ions. Theoretical calculation results show that Na not only affects the magnetic shielding and regulates the splitting and change of NMR peaks but also regulates the aggregation-free energy and growth morphology of silica nanoparticles. Thus, the structural regulation of sodium ions on nanosilica growth and aggregation was proposed. Magnetic shielding caused by partial symmetry disappears with the reduction of sodium ions in the system, resulting in uniform magnetic shielding. Meanwhile, the anisotropic aggregation free energy of microscopic particles tends to be isotropically distributed, resulting in the spherical growth tendency of the nanosilica particles. Small-angle X-ray scattering and transmission electron microscopy were used to verify these conclusions. In this work, we adopted the leading quantum chemical computational methods with advanced computer technology and quantum chemical methods to research the microscopic effect of sodium ions during nanosilica growth, thereby overcoming the limitations of the analytical experience and paradigm established with traditional organic chemistry and providing important theoretical reference value for the field of spectral systems and characterization measurement methods. At the same time, the reasonable mechanism of action is proposed, which greatly expands the product application field of nanosilica.

Plant Growth and Root Morphology Are Affected by Earthworm-Driven (Eisenia sp.) Changes in Soil Chemico-Physical Properties: a Mesocosm Experiment with Broccoli and Faba Bean

Earthworms are “ecosystem engineers” that improve soil water and nutrient content, soil macroporosity, and aeration, and provide suitable habitats for microbial populations. This study aimed at defining if the presence of epigeic earthworms (Eisenia sp.) affected the growth and development of two plant species (Brassica oleracea and Vicia faba) via the modifications of soil chemico-physical properties. A mesocosm experiment, in which plants were grown outdoors for 4 months with or without earthworms, was performed. The two plant species were selected based on their different habitus and root architecture and morphology. Soil macroporosity (Msoil) and water holding capacity (WHCsoil) were determined. Earthworm-driven bioturbation (Bsoil) was measured by filling mesh bags with artificial soil. Earthworm abundance and biomass, together with plant morphometric parameters (root and leaf morphology by imaging and microscope techniques), were measured at the end of the trial. The presence of earthworms increased Msoil (on average +16%) and WHCsoil (on average +9%) and this was accompanied by a remarkable degree of Bsoil. In most of the cases, earthworms enhanced plant growth in the two plant species studied, with a significant positive influence on the majority of the shoot and root traits. A significant increase of stomatal density (on average +24%) occurred in the leaves of both the plant species in the presence of earthworms. Our results confirmed the hypothesis that bioturbation by Eisenia sp. had a significant positive effect on plant growth, independently from the plant species cultivated, and that these growth-promoting effects were mediated by changes in soil chemico-physical parameters. By taking into account the essential role of earthworms in maintaining healthy soils and the vegetation they support, soils can become more resilient against environmental perturbations and climate change.

Stochastic Cellular Automata Modeling of CO2 Hydrate Growth and Morphology.

Carbon dioxide (CO2) hydrates are important in a diverse range of applications and technologies in the environmental and energy fields. The development of such technologies relies on fundamental understanding, which necessitates not only experimental but also computational studies of the growth behavior of CO2 hydrates and the factors affecting their crystal morphology. As experimental observations show that the morphology of CO2 hydrate particles differs depending on growth conditions, a detailed understanding of the relation between the hydrate structure and growth conditions would be helpful. To this end, this work adopts a modeling approach based on hybrid probabilistic cellular automata to investigate variations in CO2 hydrate crystal morphology during hydrate growth from stagnant liquid water presaturated with CO2. The model, which uses free energy density profiles as inputs, correlates the variations in growth morphology to the system subcooling ΔT, i.e., the temperature deficiency from the triple CO2-hydrate-water equilibrium temperature under a given pressure, and properties of the growing hydrate-water interface, such as surface tension and curvature. The model predicts that when ΔT is large, parabolic needle-like or dendrite crystals emerge from planar fronts that deform and lose stability. In agreement with chemical diffusion-limited growth, the position of such planar fronts versus time follows a power law. In contrast, the tips of the emerging parabolic crystals steadily grow in proportion to time. The modeling framework is computationally fast and produces complex growth morphology phenomena under diffusion-controlled growth from simple, easy-to-implement rules, opening the way for employing it in multiscale modeling of gas hydrates.

Theoretical study on the influence of different solvents on the growth morphology of 3,4-bis(3-nitrofurazan-4-yl)furoxan (DNTF).

3,4-bis(3-nitrofurazan-4-yl)furoxan(DNTF) is a new energetic compound with high energy and high density, and it is an important component of propellant and melt cast explosive. In order to study the effect of solvent on the growth morphology of DNTF, the growth plane of DNTF in vacuum is predicted by attachment energy(AE) model, and then the modified attachment energy of each growth plane in different solvents is calculated by molecular dynamics simulation. The morphology of crystal in solvent is predicted by modified attachment energy (MAE) model. The factors affecting crystal growth in solvent environment are analyzed by mass density distribution, radial distribution function and diffusion coefficient. The results show that the growth morphology of crystal in solvent is not only related to the adsorption strength of solvent to crystal plane, but affected by the attraction of crystal plane to solute. The hydrogen bond plays an important role in the adsorption strength between solvent and crystal plane. The polarity of solvent has a great influence on the crystal morphology, and the interaction between the solvent with stronger polarity and the crystal plane is stronger. The morphology of DNTF in n-butanol solvent is closer to spherical, which can effectively reduce the sensitivity of DNTF. The molecular dynamics simulation is carried out under the COMPASS force field of Materials Studio software. Gaussian software is used to calculate the electrostatic potential of DNTF at B3LYP-D3/6-311 + G (d, p) theoretical level.

Investigation of network microstructure of TiB/Ti6Al4V-ELI composite manufactured with laser metal deposition

This work presents the microstructural investigation of an in situ synthesized TiB/Ti6Al4V-ELI composite that was manufactured with additive manufacturing (AM) technique known as laser metal deposition (LMD). A single-track sample was manufactured by adding TiB2 to Ti6Al4V-ELI at mass deposition volume of 5% and characterized for microstructure and hardness. It was found that in situ reaction promoted the formation of quasi-continuous network microstructure of TiB whiskers with a needle-like morphology, in a martensitic α′ matrix. Furthermore, the manufactured TiB/Ti6Al4V-ELI presented two different grain growth morphologies, with smaller and large TiB network grains observed at the top and bottom of the sample, respectively, due to heat travelling direction. A high hardness of 513 HV was observed at the top of the sample, which was reduced to 483 HV at the bottom, promoted by grain growth.Graphical abstract

Investigation on mechanical properties of biomimetic mineralized mortar incorporated with boric acid modifier

Microbially induced carbonate precipitation (MICP) has been intensively studied as a potential method to improve engineering properties of soil. However, MICP has limitations due to the introduction of microorganisms and the difficulty of controlling the calcium carbonate crystal precipitation model. This study proposed biomimetic mineralized mortar based on the biomimetic-chemically induced carbonate precipitation (BCICP) method with boric acid as a crystal modifier. Similar to the bacteria in MICP, boric acid can promote the nucleation of calcium carbonate and the adsorption of calcium carbonate on the surface of sand particles. Besides, the boric acid concentration can effectively change the precipitation mode of calcium carbonate. Unconfined compression strength (UCS) test and microscopic characterization were conducted to investigate the mechanism of boric acid modifying calcium carbonate crystal growth and precipitation morphology. The results show that with the increase of boric acid concentration, the reinforcement efficiency of calcium carbonate increased. With the increase of boric acid concentration, the crystalline calcium carbonate changed from a cube-shaped calcite with a smooth surface to a spherical calcite with a rough surface and the coating pattern of calcium carbonate distribution on the surface of sand particles was weakened, while the bonding-filling pattern was enhanced. Besides, the cementing fluid concentration can also affect the reinforcement efficiency of calcium carbonate and with the participation of boric acid, biomimetic mineralized mortar can use the high concentration cementing fluid to achieve effective strength enhancement. This study confirms that boric acid could effectively modify the form and distribution of calcium carbonate between sand particles, and enhance the cementation between calcium carbonate and sand particles.

Prenatal Exposure to General Anesthesia Drug Esketamine Impaired Neurobehavior in Offspring

Prenatal exposure to anesthetics has raised increasing attention about the neuronal development in offspring. Animal models are usually used for investigation. As a new drug, esketamine is the s-isoform of ketamine and is twice as potent as the racemic ketamine with less reported adverse effects. Esketamine is currently being used and become more favorable in clinical anesthesia work, including surgeries during pregnancy, yet the effect on the offspring is unknown. The present study aimed to elucidate the effects of gestational administration of esketamine on neuronal development in offspring, using a rat model. Gestational day 14.5 pregnant rats received intravenous injections of esketamine. The postnatal day 0 (P0) hippocampus was digested and cultured in vitro to display the neuronal growth morphology. On Day 4 the in vitro experiments revealed a shorter axon length and fewer dendrite branches in the esketamine group. The results from the EdU- imaging kit showed decreased proliferative capacity in the subventricular zone (SVZ) and dentate gyrus (DG) in both P0 and P30 offspring brains in the esketamine group. Moreover, neurogenesis, neuron maturity and spine density were impaired, resulting in attenuated long-term potentiation (LTP). Compromised hippocampal function accounted for the deficits in neuronal cognition, memory and emotion. The evidence obtained suggests that the neurobehavioral deficit due to prenatal exposure to esketamine may be related to the decrease phosphorylation of CREB and abnormalities in N-methyl-d-aspartic acid receptor subunits. Taken together, these results demonstrate the negative effect of prenatal esketamine exposure on neuronal development in offspring rats.Graphical G14.5 esketamine administration influenced the neurobehavior of the offspring in adolescence. Poorer neuronal growth and reduced brain proliferative capacity in late gestation and juvenile pups resulted in impaired P30 neuronal plasticity and synaptic spines as well as abnormalities in NMDAR subunits. Attenuated LTP reflected compromised hippocampal function, as confirmed by behavioral tests of cognition, memory and emotions. This figure was completed on the website of Figdraw.

Nanoscale morphology tailoring in plasma deposited CN x layers

Magnetron discharge plasma was applied for the synthesis of CN x thin layers using methane and nitrogen gas precursors. The incorporation of nitrogen in the carbon network resulted in the dramatic evolution of growth morphology: from a ‘buried’ porous layer observed at low nitrogen incorporation to aligned bundles of nanorods grown perpendicular to the substrate surface at maximum discharge power and nitrogen flow. The films deposited at the low discharge power and high nitrogen incorporation exhibited a mesoporous sponge-like morphology after vacuum annealing. Relevant physical mechanisms responsible for the formation of nano- and mesoshaped morphology are discussed in terms of the effects of internal mechanical stresses and plasma etching. In addition, the sensing properties of the sponge-like layer were preliminarily examined in water vapor and ammonia ambients. The CN x films showed enhanced sensitivity to ammonia and reverse electrical response to moisture in comparison with a nitrogen-free nanoporous carbon film, which were assigned to modification of the electronic properties of the nitridated surface.

Evolution of the Growth Mode and Its Consequences during Bulk Crystallization of GaN.

A detailed analysis of morphology of gallium nitride crystal growth obtained by ammonothermal and halide vapor phase epitaxy methods was carried out. The work was conducted to determine the source of triangular planar defects visible in X-ray topography as areas with locally different lattice parameters. It is shown that the occurrence of these defects is related to growth hillocks. Particular attention was paid to analyzing the manner and consequences of merging hillocks. In the course of the study, the nature of the mentioned defects and the cause of their formation were determined. It was established that the appearance of the defects depends on the angle formed between the steps located on the sides of two adjacent hillocks. A universal growth model is presented to explain the cause of heterogeneity during the merging of growth hillocks.

Biology of Patanga japonica (Orthoptera, Acrididae): Nymphal growth, host plants, reproductive activity, hatching behavior, and adult morphology

The biology of Patanga japonica (Bolívar, 1898), including seasonal nymphal growth, host plants, mating, oviposition, hatching, and adult morphology, was studied under outdoor and indoor conditions in central Japan. A field census showed that this grasshopper had a univoltine life cycle and overwintered in the adult stage. Body size was found to increase with a delay in the time of adult emergence in females but not in males, and protandry was observed. The insects were mainly associated with a few plant species. Feeding tests showed that at least one of the 5 test nymphs molted to the second stadium on 37 plant species, and more than 50% did so on 23 plant species. Mating was frequently observed in April and May under outdoor conditions, and the daily maximum number of copulating pairs was positively correlated with air temperature. Copulatory behavior, including stridulation, is described in detail. Oviposition was frequently observed in May and June under outdoor conditions. Larger females produced more eggs per pod, and a negative relationship was observed between egg lengths and the number of eggs per pod, showing a trade-off. On average, female adults had 124 ovarioles. Egg hatching occurred at different times during the daytime, but the eggs from each pod hatched synchronously. Synchronous hatching was also observed in eggs kept in groups of 2, 4, and 10, but hatching occurred earlier in larger group sizes. Eggs achieved synchronous hatching by either delaying or advancing hatching time. Two eggs separated by several millimeters hatched less synchronously than those kept in contact with one another. However, similarly separated eggs restored hatching synchrony when connected by thin wire, suggesting the involvement of vibrational signals in embryo–embryo communication. Morphometric analysis suggested that P. japonica adults change some morphometric ratios in response to crowding. Variation in pronotum shape was not significantly affected by crowding.

FonTup1 functions in growth, conidiogenesis and pathogenicity of Fusarium oxysporum f. sp. niveum through modulating the expression of the tricarboxylic acid cycle genes

The Tup1-Cyc8 complex is a highly conserved transcriptional corepressor that regulates intricate genetic network associated with various biological processes in fungi. Here, we report the role and mechanism of FonTup1 in regulating physiological processes and pathogenicity in watermelon Fusarium wilt fungus, Fusarium oxysporum f. sp. niveum (Fon). FonTup1 deletion impairs mycelial growth, asexual reproduction, and macroconidia morphology, but not macroconidial germination in Fon. The ΔFontup1 mutant exhibits altered tolerance to cell wall perturbing agent (congo red) and osmotic stressors (sorbitol or NaCl), but unchanged sensitivity to paraquat. The deletion of FonTup1 significantly decreases the pathogenicity of Fon toward watermelon plants through attenuating the ability to colonize and grow within the host. Transcriptome analysis revealed that FonTup1 regulates primary metabolic pathways, including the tricarboxylic acid (TCA) cycle, via altering the expression of corresponding genes. Downregulation of three malate dehydrogenase genes, FonMDH1–3, occurs in ΔFontup1, and disruption of FonMDH2 causes significant abnormalities in mycelial growth, conidiation, and virulence of Fon. These findings demonstrate that FonTup1, as a global transcriptional corepressor, plays crucial roles in different biological processes and pathogenicity of Fon through regulating various primary metabolic processes, including the TCA cycle. This study highlights the importance and molecular mechanism of the Tup1-Cyc8 complex in multiple basic biological processes and pathogenicity of phytopathogenic fungi.