Bmp Signal Gradient Modulates Convergent Cell Movement via Xarhgef3.2 during Gastrulation of Xenopus Embryos

Gastrulation is a critical step in the establishment of a basic body plan during development. Convergence and extension (CE) cell movements organize germ layers during gastrulation. Noncanonical Wnt signaling has been known as major signaling that regulates CE cell movement by activating Rho and Rac. In addition, Bmp molecules are expressed in the ventral side of a developing embryo, and the ventral mesoderm region undergoes minimal CE cell movement while the dorsal mesoderm undergoes dynamic cell movements. This suggests that Bmp signal gradient may affect CE cell movement. To investigate whether Bmp signaling negatively regulates CE cell movements, we performed microarray-based screening and found that the transcription of Xenopus Arhgef3.2 (Rho guanine nucleotide exchange factor) was negatively regulated by Bmp signaling. We also showed that overexpression or knockdown of Xarhgef3.2 caused gastrulation defects. Interestingly, Xarhgef3.2 controlled gastrulation cell movements through interacting with Disheveled (Dsh2) and Dsh2-associated activator of morphogenesis 1 (Daam1). Our results suggest that Bmp gradient affects gastrulation cell movement (CE) via negative regulation of Xarhgef3.2 expression.

Effect of Anatomical Sites On the Mechanical Properties of Spinal Dura Subjected to Biaxial Stretching

The spinal cord is encased by spinal meninges called the pia, arachnoid, and dura maters. Among these membranes, the dura mater is the thick and outermost layer and is the toughest and strongest. Thus, mechanical failure of the dura mater can lead to spontaneous cerebrospinal fluid leaks or hypovolemia, resulting in a complication or exacerbation of unfavorable symptoms involved in a mild traumatic brain injury. To develop protective equipment that can help prevent such injuries, accurate characterization of the spinal dura mater is required, especially regarding the mechanical properties at different anatomical sites. In this study, we used an equiload biaxial tensile tester to investigate the mechanical properties of porcine meningeal dura mater along the whole length of the spine. The resultant strain of the dorsal side was greater than that of the ventral side (P < 0.01), while the circumferential direction was significantly stiffer than the longitudinal direction (P < 0.01) at lower strains regardless of the spinal level. We also found that the material stiffness progressively increased from the cervical level to the thoracolumbar level at lower strains, which implies that the dura mater inherently possesses structurally preferred features or functions because the neck requires sufficient flexibility for daily activities. Further, Young's modulus was significantly less on the dorsal side than on the ventral side at higher strains (P < 0.05), suggesting that the dorsal side is readily elongated by spinal flexion even within the range of physiological motion.

Responses of ticks to immersion in hot bathing water: Effect of surface type, water temperature, and soap on tick motor control

Preventing bites from undetected ticks through bathing practices would benefit public health, but the effects of these practices have been researched minimally. We immersed nymphal and adult hard ticks of species common in the eastern United States in tap water, using temperatures and durations that are realistic for human hot bathing. The effect of (a) different skin-equivalent surfaces (silicone and pig skin), and (b) water temperature was tested on Amblyomma americanum, Dermacentor variabilis and Ixodes scapularis nymphs. Overall, the type of surface had a much larger effect on the nymphs’ tendency to stay in contact with the surface than water temperature did. Most nymphs that separated from the surface did so within the first 10 s of immersion, with the majority losing contact due to the formation of an air bubble between their ventral side and the test surface. In addition, adult Ixodes scapularis were tested for the effect of immersion time, temperature, and soap on tick responsiveness. Some individual adults moved abnormally or stopped moving as a result of longer or hotter immersion, but soap had little effect on responsiveness. Taken together, our results suggest that the surface plays a role in ticks’ tendency to stay in contact; the use of different bath additives warrants further research. While water temperature did not have a significant short-term effect on tick separation, ticks that have not attached by their mouth parts may be rendered unresponsive and eventually lose contact with a person’s skin in a hot bath. It should be noted that our research did not consider potential temperature effects on the pathogens themselves, as previous research suggests that some tickborne pathogens may become less hazardous even if the tick harboring them survives hot-water exposures and later bites the bather after remaining undetected.

Microbial associations of shallow-water Mediterranean marine cave Solenogastres (Mollusca)

The first cave-dwelling Solenogastres—marine shell-less worm-like mollusks—were sampled from Mediterranean marine caves floor silt in the Marseille area. The mollusks were 1.5 mm in length, had a transparent body with shiny spicules and appear to represent a new Tegulaherpia species. Electron microscopy revealed a high number of microbial cells, located on the surface of the spicules as well as in the cuticle of Tegulaherpia sp. The observed microbial cells varied in morphology and were unequally distributed through the cuticle, reaching a highest density on the dorsal and lateral sides and being practically absent on the ventral side. Next Generation Sequencing (NGS) of V4 region of 16S rRNA gene amplicons, obtained from the DNA samples of whole bodies of Tegulaherpia sp. revealed three dominating microorganisms, two of which were bacteria of Bacteroidetes and Nitrospirae phyla, while the third one represented archaea of Thaumarchaeota phylum. The Operational Taxonomic Unit (OTU), affiliated with Bacteroidetes was an uncultured bacteria of the family Saprospiraceae (93–95% of Bacteroidetes and 25–44% of the total community, depending on sample), OTU, affiliated with Nitrospirae belonged to the genus Nitrospira (8–30% of the community), while the thaumarchaeal OTU was classified as Candidatus Nitrosopumilus (11–15% of the community). Members of these three microbial taxa are known to form associations with various marine animals such as sponges or snails where they contribute to nitrogen metabolism or the decomposition of biopolymers. A similar role is assumed to be played by the microorganisms associated with Tegulaherpia sp.

Embryo-scale epithelial buckling forms a propagating furrow that initiates gastrulation

Cell apical constriction driven by actomyosin contraction forces is a conserved mechanism during tissue folding in embryo development. While much effort has been made to better understand the molecular mechanisms responsible for apical constriction, it is still not clear if apical actomyosin contraction forces are necessary or sufficient per se to drive tissue folding. To tackle this question, we use the Drosophila embryo model system that forms a furrow on the ventral side, initiating mesoderm internalization. Past computational models support the idea that cell apical contraction forces may not be sufficient and that active or passive cell apico-basal forces may be necessary to drive cell wedging and tissue furrowing. By using 3D computational modelling and in toto embryo image analysis and manipulation, we now challenge this idea and show that embryo-scale force balance of the tissue surface, rather than cell-autonomous shape changes, is necessary and sufficient to drive a buckling of the epithelial surface forming a furrow which propagates and initiates embryo gastrulation.

INCIDENCE OF CERVICAL DISCOPATHY IN TOY BREEDS IN NECK AREA

The article is devoted to the determination of the incidence of discopathy in the cervical spine in dwarf dog breeds. Discopathies are widespread among all dog breeds. This pathology is common throughout the vertebral column, but in the cervical spine it occurs more often in dwarf breeds, due to the greater amplitude of movement of the vertebrae. Incidence allows a preliminary assessment of the need for surgical intervention or the use of a conservative method of treatment. This work is based on a study of 52 breeds of dogs with discopathies in the cervical spine, and in particular 21 decorative breeds. As a result of the surgical treatment of this pathology, the ventral slot technique was used. This technique allows performing an operative approach from the ventral side of the spinal column to eliminate hernial contents and ensure postoperative improvement.

A new species of Podanotum Torres & Johnson, 1996 (Lepidoptera, Lycaenidae) from northern Peru

We describe a new species of the genus Podanotum Torres & Johnson, 1996, Podanotum pajaten Farfán, Cerdeña & Bálint sp. nov. from northern Peru, associated with the Andean treeline ecotone adjacent to cloud forest and wet grassland at 3200 m above sea level. Description of this new species is based on one female adult and is distinguishable from its congeners by the combination of the following morphological characters: dorsal wing pale blue, forewing discoidal line present on ventral side, hindwing tailed, and ostium bursae distally toothed. Podanotum pajaten sp. nov. is separated geographically from the closest spatial species, P. glorissimum Bálint & Wojtusiak, 2002, by approximately 100 km to the south, and represents the second species described for Peru. An identification key to all known species of Podanotum is provided, stating their distributions by country. Publicación registrada en Zoobank/ZooBank article registered:LSIDurn:lsid:zoobank.org:pub:FE6C35CF-2609-410C-9CB5-57737D02DFC3Acto nomenclatural/nomenclatural act:Podanotum pajaten Farfán, Cerdeña & Bálint, 2021LSIDurn:lsid:zoobank.org:act:B8CE9125-0182-4DAB-BD92-D15DC4E16C47

Taxonomy of the Proisotoma complex. VI. Rediscovery of the genus Bagnallella Salmon, 1951 and epitoky in Bagnallella davidi (Barra, 2001), comb. nov. from South Africa

The genus Bagnallella Salmon is restored and given a diagnosis. It takes an intermediate position between Proisotoma Börner and Cryptopygus Willem complexes and is characterized by the separation of the two last abdominal segments (like in Proisotoma) and 3 and 5 s-chaetae on the fourth and fifth abdominal segments (like in Cryptopygus and its allies). A list of and key to species belonging to Bagnallella is given. Bagnallella bisetacomb. nov., B. dubiacomb. nov., B. sedecimoculatacomb. nov., and B. tenellacomb. nov. are commented and redescribed. Morphology of Bagnallella davidi (Barra), comb. nov. is described from the specimens from South Africa. So far B. davidi appears to be a complex of forms differing in size of the furca and macrochaetae. Two types of strongly modified males were found and described. Antennae, ventral side of abdomen, posterior edge of abdominal tergites, and mandibles are affected with epitoky. The nature of the discovered strong polymorphism is unclear.

Revisiting the morphology of the Cretaceous ommatid beetle Clessidromma palmeri (Coleoptera: Archostemata: Ommatidae)

The morphology of Clessidromma palmeri Jarzembowski et al. from mid-Cretaceous Burmese amber is revised based on a reexamination of the type specimen. Contrary to previous studies, our observation confirms that Clessidromma has open procoxal cavities. The characters such as platform on the ventral side of head, modified metacoxae, and ridges on head and pronotum are suggested to be diagnostic characters for Clessidromma. Clessidromma zengi Kirejtshuk from the same deposit is transferred into a new genus, as Kirejtomma zengi comb. nov.

Introduction of the species of the genera Cotoneaster Medik. and × Sorbocotoneaster pozdnjakovii Pojark. from the Siberian flora to the Botanical Garden acad. A. V. Fomin of Taras Shevchenko National University of Kiev (message 3 – × Sorbocotoneaster pozd

A spontaneous intergeneric hybrid of Sorbus and Cotoneaster – Pozdnyakov’s sorbocotoneaster (× Sorbocotoneaster pozdnjakovii Pojark.) is an endemic of the South Yakutia. It is known from the river basin Aldan in the areafrom the city of Tommot to the mouth of the river Uchura and on the Aldan-Amga interfluve. It grows in the undergrowthof sparse pine and larch forests on stony-gravelly limestone slopes. It was first found by L. K. Pozdnyakov, a forester,an employee of the Institute of Forest of the Siberian Branch of the USSR Academy of Sciences, on September 9, 1950,when examining forests on permafrost in Yakutia: “in the area of the confluence of the Aya-Sullalah river into Aldan,105–110 km down the Aldan from Tommot” (from the letter of L. K. Pozdnyakov to A. T. Grevtsova, 1982). The article provides data on the origin of the specimens × Sorbocotoneasters, the morphological description of leaves, flowers, fruits,the peculiarities of growth and development in conditions of Kiev, micrographs of pollen grains, micrographs of theendocarp of fruits of three forms, the beginning of the destruction of the scutellum and hypostyle from the ventral side ina hybrid of the third form. Botanical Garden named after acad. A. V. Fomin of the Taras Shevchenko National Universityof Kiev is the only ex situ conservation site in Eastern Europe of the unique Yakut hybrid × Sorbocotoneaster pozdnjakoviiwith leaves of the 1st, 2nd and 3rd forms.