Diversity of Backusella (Mucoromycotina) in south-eastern Australia revealed through polyphasic taxonomy.

Here we explore the diversity of one morphologically distinguishable genus in the Mucoromycotina, Backusella, in south-eastern Australia. We isolated more than 200 strains from locations across the states of Victoria and Tasmania. Characterization of these strains using a combination of approaches including morphology, sucrose utilization and whole genome sequencing for 13 strains, revealed 10 new species. The genetic basis for interspecies variation in sucrose utilization was found to be the presence of a gene encoding an invertase enzyme. The genus Backusella is revised and a new key for species identification produced. Given that we have more than doubled the number of species in this genus, this work demonstrates that there may be considerable undiscovered species diversity in the early diverging fungal lineages. Citation: Urquhart AS, Douch JK, Heafield TA, et al. 2021. Diversity of Backusella (Mucoromycotina) in south-eastern Australia revealed through polyphasic taxonomy. Persoonia 46: 1-25. https://doi.org/10.3767/persoonia.2021.46.01.

Recent advances in compartmentalized synthetic architectures as drug carriers, cell mimics and artificial organelles.

Compartmentalization is a key feature of biological cells which conduct their metabolic activity in individual steps isolated in distinct, separated compartments. The creation of architectures containing multiple compartments with a structure that resembles that of a biological cell has generated significant research attention and these assemblies are proposed as candidate materials for a range of biomedical applications. In this Review article, the recent successes of multicompartment architectures as carriers for the delivery of therapeutic cargo or the creation of micro- and nanoreactors that mimic metabolic activities, thus acting as artificial cells or organelles, are discussed. The developed technologies to assemble such complex architectures are outlined, the multicompartment carriers' properties which contribute to their performance in diverse applications are discussed, and their successful applications are highlighted. Finally, future directions and developments in the field are suggested.

Inclusion of water insoluble drugs in amorphous silica nanoparticles.

Amorphous silica nanoparticles (a-SiNPs) with high surface area and small pore size have been synthesized using a zwitterionic surfactant in acid media. The produced nanoparticles displayed large specific surface area (-850 m2/g) with an average particles size of 45 nm. The loading efficiency was assessed by incorporating three model water insoluble active substances Carbamazepine (CBZ), Ibuprofen (IBU) and Cyclosporin (CyA) via passive loading and it was found to varying from 15-40%. The loaded silica nanoparticles were analyzed using X-ray powder diffraction (XRPD) and differential scanning calorimetry (DSC) to investigate the state of the adsorbed active agents. CyA was found to be in amorphous state, IBU was partially crystalline while CBZ was transformed into form I. The dissolution profiles showed rapid release for CBZ while IBU and CyA demonstrated prolonged release for 24 hr. The viability of Caco-2 cells was not affected in the presence of a-SiNPs showing negligible cytotoxicity (85%) at high concentrations up to 15 mg/ml.

Centrobin regulates the assembly of functional mitotic spindles.

The proper function of the spindle is crucial to the high fidelity of chromosome segregation and is indispensable for tumor suppression in humans. Centrobin is a recently identified centrosomal protein that has a role in stabilizing the microtubule structure. Here we functionally characterize the defects in centrosome integrity and spindle assembly in Centrobin-depleted cells. Centrobin-depleted cells show a range of spindle abnormalities including unfocused poles that are not associated with centrosomes, S-shaped spindles and mini spindles. These cells undergo mitotic arrest and subsequently often die by apoptosis, as determined by live cell imaging. Co-depletion of Mad2 relieves the mitotic arrest, indicating that cells arrest due to a failure to silence the spindle checkpoint in metaphase. Consistent with this, Centrobin-depleted metaphase cells stained positive for BubR1 and BubR1 S676. Staining with a panel of centrosome markers showed a loss of centrosome anchoring to the mitotic spindle. Furthermore, these cells show less cold-stable microtubules and a shorter distance between kinetochore pairs. These results show a requirement of Centrobin in maintaining centrosome integrity, which in turn promotes anchoring of mitotic spindle to the centrosomes. Furthermore, this anchoring is required for the stability of microtubule-kinetochore attachments and biogenesis of tension-ridden and properly functioning mitotic spindle.

Adsorption geometry and core excitation spectra of three phenylpropene isomers on Cu(111).

Theoretical C 1s near edge x-ray absorption fine structure (NEXAFS) spectra for the C(9)H(10) isomers trans-methylstyrene, alpha-methylstyrene, and allylbenzene in gas phase and adsorbed at Cu(111) surfaces have been obtained from density functional theory calculations where adsorbate geometries were determined by corresponding total energy optimizations. The three species show characteristic differences in widths and peak shapes of the lowest C 1s-->pi(*) transitions which are explained by different coupling of the pi-electron system of the C(6) ring with that of the side chain in the molecules as well as by the existence of nonequivalent carbon centers. The adsorbed molecules bind only weakly with the substrate which makes the use of theoretical NEXAFS spectra of the oriented free molecules meaningful for an interpretation of experimental angle-resolved NEXAFS spectra of the adsorbate systems obtained in this work. However, a detailed quantitative account of relative peak intensities requires theoretical angle-resolved NEXAFS spectra of the complete adsorbate systems which have been evaluated within the surface cluster approach. The comparison with experiment yields almost perfect agreement and confirms the reliability of the calculated equilibrium geometries of the adsorbates. This can help to explain observed differences in the catalytic epoxidation of the three molecules on Cu(111) based on purely geometric considerations.

Primer binding site mutations affecting the typing of STR loci contained within the AMPFlSTR SGM Plus kit.

The Forensic Science Service carries out human identification and familial investigations using the AMPFlSTR SGM Plus kit (PE Biosystems, Warrington, England). We have studied approximately 42,000 parent/child allelic transfers (meioses) for deviations from expected Mendelian Inheritance patterns. Of 55 apparent mutations detected, 20 had patterns suggestive of the presence of a primer binding site mutation producing a silent/null allele. The presence of a silent allele was unequivocally demonstrated in 13 of the 20 suspected cases by using alternative primer sets. Of the 13 confirmed cases, 9 involved the D18S51 locus. As the individuals in these cases all originated from the same geographic region of the Middle East, this cluster suggests the presence of a relatively common variant D18S51 allele in that particular group. These data taken together with our previously published work, confirm that the primer binding sites utilised for amplification of the loci contained in the AMPFlSTR SGM Plus kit have highly conserved nucleotide sequences.

Sequence polymorphism in the human melanocortin 1 receptor gene as an indicator of the red hair phenotype.

We describe a minisequencing protocol for screening DNA samples for the presence of 12 mutations in the human melanocortin 1 receptor gene (MC1R), eight of which are associated with the red hair phenotype. A minisequencing profile which shows homozygosity for one of these mutations or the presence of two different mutations would strongly indicate that the sample donor is red haired. The absence of any red hair causing mutations would indicate that the sample donor does not have red hair. We report the frequencies of MC1R variants in the British red haired population.

Hodgkin's and non-Hodgkin's lymphoma of the head and neck.

OBJECTIVES/HYPOTHESIS: Lymphomas are a frequent cause of malignant lymphadenopathy in the head and neck. This study was performed to evaluate the head and neck manifestations of lymphomas and to emphasize the different presentations of Hodgkin's disease (HD) and non-Hodgkin's lymphoma (NHL). STUDY DESIGN: Retrospective review. METHODS: A retrospective review was made of all cases of lymphomas involving the head and neck at Marshfield Clinic (Marshfield, WI) between 1988 and 1996. Specifically, the clinical presentations, staging, and prognosis for HD and NHL with head and neck involvement were sought. RESULTS: Three hundred eleven patients were included in the study, 76 with HD and 235 with NHL. The median age at diagnosis for patients with HD was 27.7 years, and for patients with NHL, 67.2 years. This difference was highly significant (P <.001). No significant difference in gender was noted, with male patients occurring in 59% with HD and 49% with NHL (P=.135). Extranodal involvement including the oral cavity, oropharynx, nasopharynx, paranasal sinuses, and larynx occurred with HD in 3 patients (4%) and with NHL in 54 patients (23% P <.001). Cervical adenopathy consisted of a single node in 24% of patients with HD and 33% of those with NHL (no significant difference, P=.236). The difference in mediastinal nodal involvement was highly significant, occurring in 65% of patients with HD and 38% of patients with NHL(P <.001). Abdominal nodes occurred in 20% of cases of HD and 45% of cases of NHL (P<.001). A significant difference in constitutional symptoms was noted with 41% of cases in HD and 27% of cases in NHL (P=.020). For the percentage of patients with stage IV disease, there was a highly significant difference by diagnosis with 10% in HD and 36% in NHL (P <.001). The median follow-up time was 51 months, and 12% of patients with HD and 41% of patients with NHL died of their disease. Both the overall survival and survival from death attributable to disease were significantly better for HD(P<.001). CONCLUSIONS: Hodgkin's disease presents at a younger age and is less common than NHL. Cervical lymphadenopathy is the most common head and neck presentation for both diseases. Associated mediastinal adenopathy was more common with HD, and abdominal adenopathy with NHL. Constitutional symptoms were more common with HD. More advanced disease with a decreased overall survival was seen with NHL.

A new complication of hypothyroid coma: neurogenic dysphagia: presentation, diagnosis, and treatment.

We report the case of a patient with severe hypothyroid coma in whom hypothyroid-related neurogenic oropharyngeal dysphagia was suspected, videoscopically confirmed, and successfully treated. This complication has not previously been described, and may have contributed to the historically high mortality associated with severe cases of hypothyroid coma. In the future, the early detection and aggressive treatment of this complication and its sequelae should ensure a further reduction in mortality from hypothyroid coma.

Inferring ethnic origin by means of an STR profile.

We report the use of DNA profiles from six STR loci for inferring the ethnic origin of a crime stain and discuss how such inference may be used as intelligence information to reduce the expected number of interviews to resolve a case. To enable this work, databases have been created for five British ethnic groups (Caucasians, Afro-Caribbeans, Indian sub-continentals, Southeast Asians and Middle Easterners) that together comprise 99.7% of the UK population.

Tibiofemoral conformity and kinematics of rotating-bearing knee prostheses.

Increasing tibiofemoral articular conformity theoretically increases articular contact area and reduces contact stresses in total knee arthroplasty. Fixed-bearing knee designs possess relatively low tibiofemoral conformity, in part to allow tibiofemoral rotation without generating excessive stresses at the articulation or the implant-bone interface. This study analyzed knee kinematics of mobile-bearing designs in a closed chain dynamic knee extension model in posterior cruciate-retaining design with high- and low tibiofemoral conformity and posterior cruciate-substituting designs with and without rotational constraint. Overall, for all conditions, the mobile-bearing insert rotated with the femur in the presence of tibiofemoral axial rotation. In addition, the correlation of bearing rotation with femoral rotation was stronger for the high-conformity and rotationally-constrained designs than for the low-conformity designs and strongest for the posterior cruciate-retaining high-conformity condition. Changes in conformity or rotational constraint did not appear to affect femoral roll back, tibiofemoral axial rotation, or varus-valgus angulation. The results suggest that mobile-bearing inserts rotate with the femur and increasing conformity or rotational constraint in mobile-bearing design knee prostheses does not affect knee kinematics adversely, at least under closed chain knee extension conditions in vitro.

Preoperative computed tomography scans for parotid tumor evaluation.

OBJECTIVE: We sought to determine whether an advantage is obtained in the routine use of computed tomography (CT) scans in preoperative assessments of parotid tumors. METHODS: A prospective study of 32 consecutive cases of patients who underwent evaluation for parotidectomies was performed. Twenty-nine received preoperative CT scans. The scans were systematically reviewed to see if they correlated with the clinical findings. Specifically, we compared clinical and CT assessments of tumor size, location, density, and malignancy. Further comparisons were performed based on postoperative tissue pathology. RESULTS: In our series of patients, routine preoperative CT scans resulted in the discovery of details not revealed on clinical examination: some masses were found to be extra-parotid rather than primary parotid tumors, some tumors deemed to be deep were superficial, tumor density was more clearly identified, and certain pathology correlates were clarified. Most importantly, there were instances of detection of additional tumors in the same lobe, and in one instance in the opposite lobe, that were not otherwise noticed. CONCLUSIONS: To reduce errors of omission in the treatment of suspected parotid tumors, it would seem appropriate to consider the inclusion of CT scans for the routine preoperative evaluation of all parotid masses.

Comparison between the kinematics of fixed and rotating bearing knee prostheses.

Rotating platform mobile bearing knee implants allow for increased tibiofemoral articular conformity without restricting axial rotation. In the current study, the effect of rotating platform knee replacement with and without posterior cruciate ligament substitution on knee kinematics was investigated. Five knees were implanted sequentially implanted with standard (fixed) bearings and then with rotating platform prostheses, each in posterior cruciate retaining and substituting designs. Three-dimensional kinematics for all knees were measured in an Oxford Knee Rig, which simulates dynamic quadriceps-driven closed kinetic chain knee extension under load. Rotating bearings did not significantly change knee kinematics when compared with fixed bearings. In this in vitro model, the cruciate retaining designs stayed more anterior, and had greater net femoral roll back and tibiofemoral valgus angulation with flexion than cruciate substituting designs.

The effect of the orientation of the acetabular and femoral components on the range of motion of the hip at different head-neck ratios.

BACKGROUND: Prosthetic impingement due to poor positioning can limit the range of motion of the hip after total hip arthroplasty. In this study, a computer model was used to determine the effects of the positions of the acetabular and femoral components and of varying head-neck ratios on impingement and range of motion. METHODS: A three-dimensional generic hip prosthesis with a hemispherical cup, a neck diameter of 12.25 millimeters, and a head size ranging from twenty-two to thirty-two millimeters was simulated on a computer. The maximum range of motion of the hip was measured, before the neck impinged on the liner of the cup, for acetabular abduction angles ranging from 35 to 55 degrees and acetabular and femoral anteversion ranging from 0 to 30 degrees. Stability of the hip was estimated as the maximum possible flexion coupled with 10 degrees of adduction and 10 degrees of internal rotation and also as the maximum possible extension coupled with 10 degrees of external rotation. The effects of prosthetic orientation on activities of daily living were analyzed as well. RESULTS: Acetabular abduction angles of less than 45 degrees decreased flexion and abduction of the hip, whereas higher angles decreased adduction and rotation. Femoral and acetabular anteversion increased flexion but decreased extension. Acetabular abduction angles of between 45 and 55 degrees permitted a better overall range of motion and stability when combined with appropriate acetabular and femoral anteversion. Lower head-neck ratios decreased the range of motion that was possible without prosthetic impingement. The addition of a modular sleeve that increased the diameter of the femoral neck by two millimeters decreased the range of motion by 1.5 to 8.5 degrees, depending on the direction of motion that was studied. CONCLUSIONS: There is a complex interplay between the angles of orientation of the femoral and acetabular components. Acetabular abduction angles between 45 and 55 degrees, when combined with appropriate acetabular and femoral anteversion, resulted in a maximum overall range of motion and stability with respect to prosthetic impingement. CLINICAL RELEVANCE: During total hip arthroplasty, acetabular abduction is often constrained by available bone coverage, while femoral anteversion may be dictated by the geometry of the femoral shaft. For each combination of acetabular abduction and femoral anteversion, there is an optimum range of acetabular anteversion that allows the potential for a maximum range of motion without prosthetic impingement after total hip arthroplasty. These data can be used intraoperatively to determine optimum position.

Interaction of Pex5p, the type 1 peroxisome targeting signal receptor, with the peroxisomal membrane proteins Pex14p and Pex13p.

Pex5p, a receptor for peroxisomal matrix proteins with a type 1 peroxisome targeting signal (PTS1), has been proposed to cycle from the cytoplasm to the peroxisomal membrane where it docks with Pex14p and Pex13p, the latter an SH3 domain-containing protein. Using in vitro binding assays we have demonstrated that binding of Pex5p to Pex14p is enhanced when Pex5p is loaded with a PTS1-containing peptide. In contrast, Pex5p binding to Pex13p, which involves only the SH3 domain, occurs at 20-40-fold lower levels and is reduced when Pex5p is preloaded with a PTS1 peptide. Pex14p was also shown to bind weakly to the Pex13p SH3 domain. Site-directed mutagenesis of the Pex13p SH3 domain attenuated binding to Pex5p and Pex14p, consistent with both of these proteins being binding partners for this domain. The SH3 binding site in Pex5p was determined to lie within a 114-residue peptide (Trp(100)-Glu(213)) in the amino-terminal region of the protein. The interaction between this peptide and the SH3 domain was competitively inhibited by Pex14p. We interpret these data as suggesting that docking of the Pex5p-PTS1 protein complex at the peroxisome membrane occurs at Pex14p and that the Pex13p SH3 domain functions as an associated component possibly involved in sequestering Pex5p after relinquishment of the PTS1 protein cargo to components of the translocation machinery.

PEX13 is mutated in complementation group 13 of the peroxisome-biogenesis disorders.

The peroxisome-biogenesis disorders (PBDs) are a genetically and phenotypically diverse group of diseases caused by defects in peroxisome assembly. One of the milder clinical variants within the PBDs is neonatal adrenoleukodystrophy (NALD), a disease that is usually associated with partial defects in the import of peroxisomal matrix proteins that carry the type 1 or type 2 peroxisomal targeting signals. Here, we characterize the sole representative of complementation group 13 of the PBDs, a patient with NALD (patient PBD222). Skin fibroblasts from patient PBD222 display defects in the import of multiple peroxisomal matrix proteins. However, residual matrix-protein import can be detected in cells from patient PBD222, consistent with the relatively mild phenotypes of the patient. PEX13 encodes a peroxisomal membrane protein with a cytoplasmically exposed SH3 domain, and we find that expression of human PEX13 restores peroxisomal matrix-protein import in cells from patient PBD222. Furthermore, these cells are homozygous for a missense mutation at a conserved position in the PEX13 SH3 domain. This mutation attenuated the activity of human PEX13, and an analogous mutation in yeast PEX13 also reduced its activity. The mutation was absent in >100 control alleles, indicating that it is not a common polymorphism. Previous studies have demonstrated extragenic suppression in the PBDs, but the phenotypes of patient PBD222 cells could not be rescued by expression of any other human PEX genes. Taken together, these results provide strong evidence that mutations in PEX13 are responsible for disease in patient PBD222 and, by extension, in complementation group 13 of the PBDs.

Polyethylene wear after total hip arthroplasty: the effect of a modular femoral head with an extended flange-reinforced neck.

The use of modular components in total hip arthroplasty has been thought to contribute to accelerated polyethylene wear. Specifically, a modular femoral head with a flange extension and a longer neck may cause increased wear. The purpose of the current study was to evaluate the effect of a flange extension on polyethylene wear. Ninety-one patients who had had a total of 100 primary total hip arthroplasties were evaluated after an intermediate duration of follow-up. All of the acetabular components consisted of a hemispherical titanium-alloy fiber-mesh porous-coated shell with a nonelevated modular polyethylene liner; they were inserted without cement and with use of supplemental screws through the dome after so-called line-to-line reaming. All of the femoral components consisted of a modular head with a diameter of twenty-eight millimeters and either a long neck (with a flange extension) or a short or medium neck (without a flange extension). The study group comprised sixty-two patients (sixty-six hips) who had had radiographic evaluation that was adequate to allow the valid measurement of polyethylene wear. Thirty-two hips were in men, and thirty-four were in women. The mean age of the patients was fifty-six years, the mean weight was seventy-three kilograms, and the mean duration of follow-up was 6.1 years (range, four to eight years). The rate of polyethylene wear in the eleven hips in which the femoral component had a flange extension was significantly greater than that in the fifty-five in which the femoral component did not have a flange extension (mean, 0.17 compared with 0.11 millimeter per year; p = 0.009). Multivariate analysis showed that the presence of a flange extension was associated with increased polyethylene wear to a greater degree (F = 2.86) than were all other variables that were measured, including a younger age (F = 1.72), a more vertical angle of the acetabular component (F = 0.49), a heavier weight (F = 0.14), male gender (F = 0.11), and a smaller initial thickness of the polyethylene (F = 0.02). These data support an association between the presence of a modular femoral head with a flange extension and an accelerated rate of polyethylene wear. The presumed mechanism is an increase in peripheral, or so-called rim, impingement of the flange-reinforced neck on the acetabulum due to a decrease in the ratio between the diameters of the femoral head and neck.

New reference allelic ladders to improve allelic designation in a multiplex STR system.

This paper reports the composition of a new reference allelic ladder mixture for use with a multiplex DNA profiling system consisting of six short tandem repeat loci. The loci included in this mixture are HUMTH01, D21S11, D18S51, D8S1179, HUMVWAF31/A, HUMFIBRA/FGA and an amelogenin sex test. Sequence analysis of individual ladder alleles was carried out and allelic designations made in accordance with the recommendations of the International Society of Forensic Haemogenetics (1992; 1994). A series of rare alleles which increase the range of alleles previously reported were identified. By including some of the rare alleles into the ladder marker system, we have significantly improved the ability to identify new alleles in unknown samples.

Pubic symphysis repair strength in simulated bladder exstrophy using a sheep model.

OBJECTIVES: To investigate the mechanical strength of various pubic symphysis suture material in a simulated animal model of neonatal bladder exstrophy. METHODS: Neonatal lamb pelves, which are the approximate size of neonatal human pelves, were used. Twenty-four neonatal lamb pelves were divided into four equal groups. A midline symphysotomy was made through the cartilaginous pubic symphysis in three groups and repaired using two figure-of-eight sutures (size 0) placed through the cartilaginous pubis using polypropylene, braided polyester, or polyglactin. The fourth group served as the control. The pelves were then tested to ultimate load in pure tension at a strain rate of 0.25 mm/s until failure. RESULTS: There was a highly significant difference between the intact specimens and the repaired specimens (P = 0.0008). For the repaired specimens, there was a significant difference in the ultimate load normalized by pubic height between those repaired with polypropylene and polyglactin (P = 0.025), but not for those repaired with polypropylene and braided polyester (P = 0.11) or braided polyester and polyglactin (P = 0.11). CONCLUSIONS: Braided resorbable sutures are recommended for pubic symphysis repair, because they have a lower tendency to cut out of the cartilage.