Gross anatomy of the gluteal and posterior thigh muscles in koalas based on their innervations

There are not many descriptions of the muscle morphology of marsupials, despite the fact that they should show diversity according to the adaptation and dispersal to a variety of environments. Most of the previous studies regarding the gross anatomy of marsupials were conducted in the 1800 - 1900’s, and many issues still remain that need to be reexamined. For instance, the muscle identification had been performed based only on their attachments and thus, muscle descriptions are often inconsistent among the studies. These classic studies often do not include figures or photographs, so the discrepancies in the descriptions of the muscles could only be verified by performing the muscle identification again with a more reliable method. This problem can be solved by performing muscle identification by innervation. This method, which focuses on the ontogenic origin of the muscle as opposed to the attachment site, is prone to individual and interspecies variation and is a common technique in recent anatomical research. This technique is more reliable than previous methods and is suitable for comparison with other taxa (i.e., eutherians). In this study, we first conducted muscle identification based on innervation in the gluteal and posterior thighs of koalas in order to reorganize the anatomical knowledge of marsupials. This is because the gluteus and posterior thighs of koalas are the areas where previous studies have been particularly inconsistent. We dissected five individual koalas and clarified discrepancies in previous studies, as well as investigated the unique muscle morphology and their function in koalas. Specifically, the koala's gluteal muscle group is suitable for abduction, while the posterior thigh muscles are particularly suitable for flexion. In the future, we will update the anatomical findings of marsupials in the same way to clarify the adaptive dissipation process of marsupials, as well as to contribute to the understanding of the evolutionary morphology of mammals.

Staphylococcal Phages Adapt to New Hosts by Extensive Attachment Site Variability

A growing number of humans are being infected by antibiotic resistant Staphylococcus aureus originating from livestock. The preference of S. aureus for humans or animals is in part determined by factors encoded by viruses (phages) that reside in the bacterial genome.

Different Physiology in the Jellyfish Cassiopea xamachana and C. frondosa in Florida Bay

The jellyfish Cassiopea xamachana and C. frondosa co-occur within some habitats in the Florida Keys, but the frequency with which this occurs is low. It is hypothesized that the symbiosis with different dinoflagellates in the Symbiodiniaceae is the reason: the medusae of C. xamachana contain heat-resistant Symbiodinium microadriaticum (ITS-type A1), whereas C. frondosa has heat-sensitive Breviolum sp. (ITS-type B19). Cohabitation occurs at depths of about 3–4 m in Florida Bay, where the water is on average 0.36 °C cooler, or up to 1.1 °C cooler per day. C. frondosa tends not to be found in the warmer and shallower (<2 m) depths of Florida Bay. While the density of symbionts is about equal in the small jellyfish of the two species, large C. frondosa medusae have a greater density of symbionts and appear darker in color compared to large C. xamachana. However, the number of symbionts per amebocyte are about the same, which implies that the large C. frondosa has more amebocytes than the large C. xamachana. The photosynthetic rate is similar in small medusae, but a greater reduction in photosynthesis is observed in the larger medusae of C. xamachana compared to those of C. frondosa. Medusae of C. xamachana have greater pulse rates than medusae of C. frondosa, suggestive of a greater metabolic demand. The differences in life history traits of the two species were also investigated to understand the factors that contribute to observed differences in habitat selection. The larvae of C. xamachana require lower concentrations of inducer to settle/metamorphose, and they readily settle on mangrove leaves, submerged rock, and sand compared to the larvae of C. frondosa. The asexual buds of C. xamachana are of a uniform and similar shape as compared to the variably sized and shaped buds of C. frondosa. The larger polyps of C. frondosa can have more than one attachment site compared to the single holdfast of C. xamachana. This appears to be an example of niche diversification that is likely influenced by the symbiont, with the ecological generalist and heat-resistant S. microadriaticum thriving in C. xamachana in a wider range of habitats as compared to the heat-sensitive symbiont Breviolum sp., which is only found in C. frondosa in the cooler and deeper waters.

Characterisation and Molecular Analysis of an Unusual Chimeric Methicillin Resistant Staphylococcus Aureus Strain and its Bacteriophages

In the context of microarray-based epidemiological typing of the clonal organism Staphylococcus aureus/MRSA, a strain was identified that did not belong to known clonal complexes. The molecular analysis by microarray-based typing yielded signals suggesting that it was a mosaic or hybrid strain of two lineages. To verify this result, the isolate was sequenced with both, short-read Illumina and long-read Nanopore technologies and analysed in detail. This supported the hypothesis that the genome of this strain, ST6610-MRSA-IVg comprised of segments originating from two different clonal complexes (CC). While the backbone of the strain’s genome, i.e., roughly 2 megabases, belongs to CC8, a continuous insert of 894 kb (approx. 30% of the genome) originated from CC140. Beside core genomic markers in the normal succession and orientation, this insert also included the mecA gene, coding for PbP2a and causing methicillin resistance, localised on an SCCmec IVg element. This particular SCCmec type was also previously observed in CC140 MRSA from African countries. A second conspicuous observation was the presence of the trimethoprim resistance gene dfrG within on a prophage that occupied an attachment site normally used by Panton-Valentine Leucocidin phages. This observation could indicate a role of large-scale chromosomal recombination in the evolution of S. aureus as well as a role of phages in the dissemination of antibiotic resistance genes.

Validation of an Echidna Forelimb Musculoskeletal Model Using XROMM and diceCT

In evolutionary biomechanics, musculoskeletal computer models of extant and extinct taxa are often used to estimate joint range of motion (ROM) and muscle moment arms (MMAs), two parameters which form the basis of functional inferences. However, relatively few experimental studies have been performed to validate model outputs. Previously, we built a model of the short-beaked echidna (Tachyglossus aculeatus) forelimb using a traditional modelling workflow, and in this study we evaluate its behaviour and outputs using experimental data. The echidna is an unusual animal representing an edge-case for model validation: it uses a unique form of sprawling locomotion, and possesses a suite of derived anatomical features, in addition to other features reminiscent of extinct early relatives of mammals. Here we use diffusible iodine-based contrast-enhanced computed tomography (diceCT) alongside digital and traditional dissection to evaluate muscle attachments, modelled muscle paths, and the effects of model alterations on the MMA outputs. We use X-ray Reconstruction of Moving Morphology (XROMM) to compare ex vivo joint ROM to model estimates based on osteological limits predicted via single-axis rotation, and to calculate experimental MMAs from implanted muscles using a novel geometric method. We also add additional levels of model detail, in the form of muscle architecture, to evaluate how muscle torque might alter the inferences made from MMAs alone, as is typical in evolutionary studies. Our study identifies several key findings that can be applied to future models. 1) A light-touch approach to model building can generate reasonably accurate muscle paths, and small alterations in attachment site seem to have minimal effects on model output. 2) Simultaneous movement through multiple degrees of freedom, including rotations and translation at joints, are necessary to ensure full joint ROM is captured; however, single-axis ROM can provide a reasonable approximation of mobility depending on the modelling objectives. 3) Our geometric method of calculating MMAs is consistent with model-predicted MMAs calculated via partial velocity, and is a potentially useful tool for others to create and validate musculoskeletal models. 4) Inclusion of muscle architecture data can change some functional inferences, but in many cases reinforced conclusions based on MMA alone.

Proteolytic Transformation and Stimulation of SARSCov-2 Spike Protein with Human ACE-2 Receptor

Severe acute respiratory syndrome coronavirus has a great role in causing respiratory illness in humans and has the most important relationship of its spike proteins with host ACE-2 receptors. After entry into the human body, the viral S protein receptor-binding domain binds to human ACE-2 receptor. Two modes explained in this paper of an ACE-2 shedding. The shedding induces the process of viral entry to host cells by binding SARS-CoV-2 proteins. The residues of arginine and lysine in the ACE-2 receptor from 652 to 659 amino acid cleavage by ADAM17 but in TMPRSS2 the residues can be seen on amino acid from 697 to 716. Corona virus genome shows some structural proteins that are responsible for the cellular entry and facilitate the attachment of a virus to the host cell. Virus recognizes the attachment site and binds with it and enter into the cell. Spike protein is split from the cleavage site along its two subunits S1 and S2 then during this process. S2 subunit release RBD (Receptor- Binding Domain) of S1 mediated to the ACE-2. The RBD of S1 consists of 200 amino acid domains. The unknown protein B6ATI which is a neutral amino acid transporter located in ileum is the basic cause for formation of ACE-2 homodimer. In this way S1 domain provides site for another S2 domain. This leads to concealing of the ACE-2 ectodomain cleavage-sites, shedding. It prevents endocytosis of the receptor blocking a major pathway in the viral entry.

A Systematic Review of Definitive Treatment for Inverted Papilloma Attachment Site and Associations With Recurrence

Objective Inverted papilloma (IP) is the most common benign neoplasm of the nasal cavity with known risk of recurrence. There is no standardized approach to definitive treatment for attachment sites. This systematic review aims to determine whether surgeon choice of technique differs by anatomic attachment site and whether different surgical techniques contribute to reduced rates of recurrence. Data Sources PubMed and Ovid Medline. Review Methods A systematic review was conducted for studies reporting on IP. Those that included IP recurrence rates and primary tumor attachment site were reviewed. Results Of 122 published studies, 14 met eligibility criteria, representing 585 patients and a recurrence rate of 5.8%. The maxillary sinus (50.9%) was the most common primary attachment site, and the sphenoid sinus was associated with the highest rate of recurrence (10.4%). The most utilized technique included debulking the tumor, removing mucosa over the attachment site, and drilling the underlying bone. The most common Krouse stage represented was T3 (53.3%). No single technique predicted a propensity for recurrence, but certain techniques are favored depending on IP attachment site. Finally, frozen sections to obtain evidence of clear margins intraoperatively significantly reduced rates of recurrence (3.4% vs 7.3%, P = .045). Conclusion Based on the current literature, the most common technique to address site of attachment involves resecting mucosa and drilling the tumor base. Choice of technique appears to differ for various sites of attachment. Use of intraoperative frozen section analysis appears to be associated with decreased recurrence overall. Level of Evidence 3.

ANTEROLATERAL LIGAMENT AS ROTATION STABILISER OF KNEE- JOINT. THE ROLE OF MRT AND ULTRASONOGRAPHY IN UNDERSTANDING ITS ANATOMY AND IN SELECTING SURGICAL TREATMENT STRATEGY FOR ITS INJURIES

Objective. To assess the variability of the anterolateral ligament according to MRT and ultrasonography data and to coordinate it with surgical treatment strategy for its injuries. Methods. The anterolateral ligament was analyzed on 100 series of MRI images of knee joints without traumatic pathology on Philips Achieva 1.5 T tomograph using the standard research protocol in three mutually perpendicular planes and 150 series of MRT images of knee joints with injuries and without injuries of the anterolateral ligament obtained on different tomographs from 0.2 to 3 Tesla. The quality of visualization of anterolateral ligament separate portions, the number of layers, and the contact with the joint capsule were evaluated. Both knee joints were analyzed by ultrasonography in 30 patients with anterior cruciate ligament injuries of one of the knee-joint and in 30 patients with intact knee-joints. Results. During the studies in the identification of anterolateral ligament with magnetic resonance tomography (MRT 1.5T)it was revealed at least partially in 92% of cases (in 68% as a two-layer structure; in 24% as a single-layer structure; in 14% as a thickening of the capsule or in 10% as a separate extracapsular structure), ultrasound examination - in 100% (the structure was not determined, however, in 26.67% of patients without clinically pronounced pathology of the knee-joint and significant trauma in anamnesis ultrasound scan revealed a violation of the integrity of the cortical layer at the tibial attachment site), Conclusion. According to MRT and ultrasonography data, the anterolateral ligament is a constant structure of the knee-joint, but very variable in its anatomical parameters, which in some cases may be poorly visualized on MRT, may have a two-layer structure, may be located either extracapsular or as a thickening of the knee-joint capsule. The variability of its anatomical structure makes it impossible to make the theoretical substantiation of the advantages of one separate method of its restoration, but, on the contrary, justifies a differentiated approach to the selection of optimal surgical treatment. What this paper adds With the help of current research methods, the normal anatomical parameters and anatomical variants of the anterolateral ligament of the knee joint have been clarified and detailed. It is necessary to emphasize the importance of a differentiated approach to choosethe optimal methods of surgical treatment for its injuries.

Microscopic Diffusion Characteristics of Linear Alkylbenzene Sulfonates on the Surface of Anthracite: The Influence of Different Attachment Sites of Benzene Ring in the Backbone

In order to explore the effect of the attachment site of the benzene ring in the backbone of the surfactant on its diffusion characteristics on the surface of anthracite, the molecular dynamics simulation method was used, and the four isomers (m-C16, m = 2,4,6,8; m represents the attachment site of the benzene ring in the backbone) of sodium hexadecyl benzene sulfonate (SHS) were selected. Binary models of surfactant/anthracite, surfactant/graphene modified by oxygen-containing functional groups, and a ternary model of water/surfactant/anthracite were constructed. By analyzing a series of properties such as interaction energy, contact surface area, relative concentration distribution, radial distribution function, hydrophobic tail chain order parameter, etc., it is concluded that the adsorption strength of 4-C16 on the surface of anthracite is the highest; the reason is that 4-C16 has the highest degree of aggregation near the oxygen-containing functional groups on the surface of anthracite. Further investigations find that 4-C16 can be densely covered on the ketone group, and the longer branch chain of 4-C16 has the highest degree of order in the Z-axis direction.