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[This corrects the article DOI: 10.3389/fmicb.2021.709371.].

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Nitrogen cycling microbes, including nitrite-oxidizing bacteria (NOB), perform critical ecosystem functions that help mitigate anthropogenic stresses and maintain ecosystem health. Activity of these beneficial nitrogen cycling microbes is dictated in part by the microorganisms' response to physicochemical conditions, such as temperature, pH, and nutrient availability. NOB from the newly described Candidatus Nitrotoga genus have been detected in a wide range of habitats across the globe, yet only a few organisms within the genus have been physiologically characterized. For freshwater systems where NOB are critical for supporting aquatic life, Ca. Nitrotoga have been previously detected but little is known about the physiological potential of these organisms or their response to changing environmental conditions. Here, we determined functional response to environmental change for a representative freshwater species of Ca. Nitrotoga (Ca. Nitrotoga sp. CP45, enriched from a Colorado river). The physiological findings demonstrated that CP45 maintained nitrite oxidation at pH levels of 5-8, at temperatures from 4 to 28°C, and when incubated in the dark. Light exposure and elevated temperature (30°C) completely halted nitrite oxidation. Ca. Nitrotoga sp. CP45 maintained nitrite oxidation upon exposure to four different antibiotics, and potential rates of nitrite oxidation by river sediment communities were also resilient to antibiotic stress. We explored the Ca. Nitrotoga sp. CP45 genome to make predictions about adaptations to enable survival under specific conditions. Overall, these results contribute to our understanding of the versatility of a representative freshwater Ca. Nitrotoga sp. Identifying the specific environmental conditions that maximize NOB metabolic rates may ultimately direct future management decisions aimed at restoring impacted systems.

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The CH3 + HO2 reaction system was studied theoretically by a newly developed, HEAT345-(Q) method based CHEAT1 protocol and includes the combined singlet and triplet potential energy surfaces. The main simplification is based on the CCSDT(Q)/cc-pVDZ calculation which is computationally inexpensive. Despite the economic and black-box treatment of higher excitations, the results are within 0.6 kcal/mol of the highly accurate literature values. Furthermore, the CHEAT1 surpassed the popular standard composite methods such as CBS-4M, CBS-QB3, CBS-APNO, G2, G3, G3MP2B3, G4, W1U, and W1BD mainly due to their poor performance in characterizing transition states (TS). For TS structures, various standard DFT and MP2 method have also been tested against the resulting CCSD/cc-pVTZ geometry of our protocol. A fairly good agreement was only found in the cases of the B2PLYP and BHandHLYP functionals, which were able to reproduce the structures of all TS studied within a maximum absolute deviation of 7%. The complex reaction mechanism was extended by three new low lying reaction channels. These are indirect water elimination from CH3OOH resulted formaldehyde, H2 elimination yielded methylene peroxide, and methanol and reactive triplet oxygen were formed via H-shift in the third channel. CHEAT1 protocol based on HEAT345-(Q) method is a robust, general, and cheap alternative for high accurate kinetic calculations.

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Bursopentin (BP(5), H-Cys(1)-Lys(2)-Arg(3)-Val(4)-Tyr(5)-OH), found in the bursa Fabricius of the chicken, is a pentapeptide that protects the organism from oxidative stress by reducing the intracellular generation of reactive oxygen species. Hydrogen abstraction, a common oxidative reaction occurring in proteins, often results in the formation of d amino acid residues. To study the effect of this phenomenon on the structure of bursopentin, each of its residues were converted from the l configuration to the d configuration, and the structures of these peptide epimers were compared to that of the wild-type bursopentin. The conformations, secondary structures, compactness and hydrogen bonding of bursopentin were compared to its epimers using molecular dynamics simulations and first principles quantum chemical computations. It was discovered that the repulsion between the side chains of Lys(2) and Arg(3) influenced the conformation of the peptide regardless of the configuration of these residues. Epimerisation of the Val(4) and Tyr(5) caused a reduction in the compactness of bursopentin. In all cases, the occurrence of a turn structure was relatively high, especially when Arg(3) was in the d configuration. Thermodynamic analysis of the epimerisation process showed that the formation of d amino acid residues is favourable.

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AIMS: To determine whether left-to-right asymmetry of the central tarsal bone (CTB) of racing greyhounds was detectable using computed tomography (CT) in live dogs; to quantify the asymmetry in terms of average bone volume, volumetric bone mineral density (vBMD), and dorsal cortical shape, and to determine if age, gender, bodyweight, number of starts or history of tarsal injury were significant covariates. METHODS: One trainer supplied 11 male and seven female, unrelated, skeletally mature, actively racing greyhounds, including dogs with a history of tarsal injury diagnosed by the trainer and/or track veterinarian (n=8), and dogs without a history of tarsal injury (n=10). Using CT, standardised parameters of the CTB were measured including volume and average vBMD of the left and right CTB, vBMD of regions within the CTB, and bone shape. RESULTS: There was no difference in the volumes of the left and right CTB and no association with number of racing starts. Volume of CTB in dogs with a history of tarsal injury was greater than in dogs with no history of injury (p<0.001). Mean vBMD of the right was greater than the left CTB (p=0.004), and was independent of history of injury, gender, bodyweight, and number of starts. Males with a history of injury weighed more than those with no history of injury (p=0.004). The region of greatest difference in vBMD between right and left limbs was the centrodorsomedial aspect of the CTB. Middle plantar ligament enthesiopathies and fractures of tarsal bones other than the central tarsal bone were identified in dogs with and without a history of tarsal injury. CONCLUSIONS: Significant left-to-right asymmetry of the CTB in racing greyhounds was detected using CT. Contrary to previous suggestions, the asymmetry was not associated with the number of racing starts. We propose that the majority of the adaptive modelling of the CTB occurred rapidly following the onset of counter-clockwise training, with little further modelling throughout the racing career of the dog, however further investigation is warranted. CLINICAL RELEVANCE: This study described a technique using CT for imaging the CTB in live dogs, which opens the way for a longitudinal study of bone modelling of the CTB in response to training and racing in a counter-clockwise direction.

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CASE HISTORIES: Four adult kunekune pigs developed facial swelling at the base of the right ear that ruptured and discharged food material. A further six pigs that had similar clinical signs were reported by members of the New Zealand Kunekune Association who responded to an email survey, one of which was confirmed by post-mortem examination. CLINICAL FINDINGS: Inside the mouth of each pig there was an opening at the junction of the body and ramus of the mandible just lateral to the most caudal visible molar that was impacted with masticated feed. The food packed into the mandible resulted in infection and progressive erosion of the medullary cavity of the bone until it reached the ramus where it eroded through the lateral cortex. The feed material then tracked through the soft tissues to form a subcutaneous abscess, which eventually ruptured resulting in a draining lesion. In Case 2, which had had the lesion for 2 years, the cavity in the mandible was lined with mucosa that had healed to the skin to produce a fistula. In all four pigs there was also a lesion in the left side of the mandible that was not as developed as that on the right side. DIAGNOSIS: The facial swellings were produced by feed material that had impacted into the mandible through an opening immediately caudal to the cheek teeth and then emerged through one or more lesions in the lateral aspect of the ramus of the mandible. CLINICAL RELEVANCE: Although it has not been previously reported, anecdotal reports and our survey suggest that this condition may occur relatively frequently in kunekune pigs. It should be considered as a differential diagnosis for facial swellings and discharging lesions in these animals.

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CASE HISTORY: An 8-month-old male Pit Bull Terrier was presented with bilateral firm swellings of the cranium in the region of the frontal sinuses. The dog was aggressive when approached and had also been anorexic during the 3.5 days prior to presentation. CLINICAL FINDINGS: Using computed tomography (CT) and radiology, periosteal new bone formation and hyperostosis were detected on the frontal, parietal and mandibular bones bilaterally. Histopathology of the calvarial and mandibular bones was similar, comprised of thick trabeculae of immature woven and mature lamellar bone separated by cementing lines. Sites of prominent osteoblastic and osteoclastic activity were also present. DIAGNOSIS: Craniomandibular osteopathy with clinical similarities to calvarial hyperostosis. CLINICAL RELEVANCE: Pit Bull Terriers are not predisposed to either craniomandibular osteopathy or calvarial hyperostosis. This observation, in addition to the clinical and pathological similarities between the two diseases, suggests that craniomandibular osteopathy and calvarial hyperostosis may represent a single disorder, with predilection sites that vary between breeds of dog. We propose a new term, idiopathic canine juvenile cranial hyperostosis, for this disorder, to include both craniomandibular osteopathy and calvarial hyperostosis.

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AIM: To conduct a pilot study investigating the incidence and pathology of spondylosis in a sample of cull rams in New Zealand. METHODS: Vertebral columns from 51 cull rams from different properties were assessed radiographically for evidence of spondylosis. They were graded according to severity, using a four-point grading system. Samples of intervertebral discs representing different grades of spondylosis were examined histopathologically. RESULTS: Forty (78%) rams had spondylosis in at least one intervertebral space. Of these, 11 had ankylosis involving one or more intervertebral spaces. The frequency of spondylosis was greater in the thoracic than lumbar region (p<0.001), and was most frequent between T10-T11. Histopathological examination of intervertebral discs associated with all grades of spondylosis revealed degenerative changes in the annulus fibrosis. CONCLUSIONS: Spondylosis appeared to be common in cull rams and affected thoracic and lumbar vertebrae. It often involved ankylosis of adjacent vertebrae, and was associated with degeneration of the intervertebral disc. CLINICAL RELEVANCE: Spondylosis may reduce the serving ability of rams and be an important underlying reason for culling. The pathogenesis of spondylosis is unknown but may involve high mating frequencies during the breeding season.

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CASE HISTORY: A 4-year-old female Labrador Retriever was diagnosed with an osteolytic lesion of the right distal radius. CLINICAL FINDINGS: Radiographs indicated a well-circumscribed radiolucent area 18 x 15 x 8 mm, centred on the distal radial physeal scar. DIAGNOSIS: Histopathology, performed via Jamshidi needle biopsy and following surgical curettage, was inconclusive but suggested either an aneurysmal bone cyst or fibrous dysplasia. CLINICAL RELEVANCE: A novel processed cancellous bovine bone xenograft was used in conjunction with autogenous cancellous bone (at a ratio of approximately 4:1) to fill the curetted defect. There were no observed complications associated with the use of this new biomaterial. Osteointegration of the bone graft was followed using conventional radiographs and peripheral quantitative computed tomography (pQCT) for 10 months post-operatively. Radiographically, the osteolytic lesion modelled to resemble metaphyseal trabeculation. The cross-sectional area and the average bone density of the grafted lesion determined using pQCT data increased over time, suggesting healthy osteoconduction and native bone production.

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A 12-year-old fox-terrier dog presented with forelimb lameness of 3-weeks duration. Ultrasonography revealed a mass within the thoracic wall and osteolysis of the left third rib. A squamous cell carcinoma was diagnosed by cytological examination of an ultrasound-guided fine needle aspirate of this mass. As a result of the diagnosis of neoplasia, the dog was euthanatized. Necropsy revealed a solitary expansile mass within the left cranial lung lobe, and a mass within the adjacent thoracic wall. Thickening of the pleura between the two masses was visible, although adhesions were not present. Histology of both masses revealed a well-differentiated squamous cell carcinoma. To the authors' knowledge, this is the first detailed description of direct invasion of the thoracic wall by a canine lung tumour.

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CASE HISTORY: A 14-year-old neutered male Bearded Collie was presented with a history of recurrent, intermittent urinary incontinence of 7 years duration. CLINICAL FINDINGS: A large, firm, non-painful mass was found in the mid-abdominal region on palpation. Ultrasonography of the mass revealed a compartmentalised structure with mixed echogenicity, and which did not appear to be associated with any of the abdominal organs. Ultrasound-guided fine needle aspirates contained several clusters of epithelial cells with cytological features of hepatocytes. At exploratory laparotomy, the mass was found in the gastrosplenic ligament within the greater omentum. PATHOLOGICAL FINDINGS AND DIAGNOSIS: Histopathologically, the mass consisted of sheets of hepatocytes, but without the characteristic hepatic architecture. The cells showed moderate variation in nuclear size and were sometimes binucleate. A diagnosis of hepatocellular carcinoma (HCC) in the mesentery was made. CLINICAL RELEVANCE: The presence of ectopic hepatic tissue has been reported rarely in man and cats, but not in the dog. Neoplastic transformation of ectopic hepatic tissue is seen in man. This is the first report of the presentation, clinical findings and treatment of a dog with ectopic HCC.

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CASE HISTORY: An adult male Birman cat was evaluated for recurrent, intermittent vomiting or regurgitation, occasionally associated with abdominal discomfort. CLINICAL FINDINGS AND DIAGNOSIS: Radiographs, including an oesophogram, indicated an oesophageal obstruction. Prior to treatment, the cat's condition deteriorated and it was euthanised at the owner's request. Post-mortem examination revealed a gastro-oesophageal intussusception, a trichobezoar impacted into the intussusceptum, and a dilated oesophageal hiatus consistent with a chronic hiatal hernia. CLINICAL RELEVANCE: Gastro-oesophageal intussusception is a rare condition in cats. Its aetiology in relation to a pre-existing hiatal hernia and a trichobezoar is discussed.

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The aim of this study was to determine the prevalence and potential significance of finding material in the middle ear of dogs having magnetic resonance (MR) imaging. Of 466 MR studies reviewed, an increased signal was identified in the tympanic bulla in 32 (7%) dogs. Cavalier King Charles spaniels, Cocker spaniels, Bulldogs, and Boxers were over-represented compared to the population of dogs having MR imaging. Five (16%) dogs had definite otitis media and one (3%) had a meningioma invading the middle ear. Of the remaining dogs, 13 (41%) had possible otitis media and 13 (41%) had neurologic conditions apparently unrelated to otitis media. The most common appearance of material in the middle ear was isointense in T1-weighted images and hyperintense in T2-weighted images. There was no apparent correlation between the signal characteristics of the material and the diagnosis. Enhanced signal after gadolinium administration was observed affecting the lining of the bulla in dogs with otitis media and in dogs with unrelated neurologic conditions. In dogs without clinical signs of otitis media, finding an increased signal in the middle ear during MR imaging may reflect subclinical otitis media or fluid accumulation unrelated to inflammation. Brachycephalic dogs may be predisposed to this condition.

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An otherwise unexplained, persistently elevated plasma alkaline phosphatase concentration in a 71-year-old woman was found to be attributable to the presence of macro-alkaline phosphatase using polyethylene glycol precipitation. Gel filtration showed two high MW peaks with masses of about 330 kDa and 560 kDa. The alkaline phosphatase (ALP) complex was characterized by immunoelectrophoresis as a complex with IgG with kappa light chains.

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PURPOSE: Prostate specific antigen (PSA) is found in high concentration in prostate tissue and in semen, in which its physiological function appears to be liquefaction. In prostate cancer the peripheral PSA concentration is elevated, which may be used as a disease marker. Systemic and local immune defects have been demonstrated in prostate cancer and we postulated a role for PSA in this immunosuppression. We explored the effects of PSA on human T-lymphocyte proliferation in vitro. MATERIALS AND METHODS: PSA was purified from normal seminal plasma using a modified chromatographic technique. The effect of PSA or control protein on lymphocyte responses to mitogens, tetanus toxoid and alloantigens was tested. The inhibitory effect observed was further explored by varying the time of PSA addition, denaturing PSA and including interleukin-2 and anti-PSA antibodies. RESULTS: PSA suppressed in vitro phytohemagglutinin and alloantigen stimulated lymphocyte proliferation in a dose dependent manner. This effect was reversed by adding anti-PSA antibodies but not by interleukin-2. CONCLUSIONS: These in vitro PSA effects suggest another T-lymphocyte mediated immunosuppressive mechanism. In vivo high levels of PSA may compromise natural immune responses to cancer and current attempts at immunotherapy for prostate cancer.

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Hb Footscray, alpha 133(H16) Ser-->Arg, is a newly described hemoglobin variant found in an adult male of Polish-Hungarian descent. Hematological data and stability by the isopropanol stability test were normal. The abnormal hemoglobin comprised 15% of total hemoglobin and migrated as a split band in the Hb F position on cellulose acetate at pH 8.6. Like Hb Manitoba, which is also a Ser-->Arg mutation and occurs in a very similar spatial position, the split bands presumably arise from the formation of asymmetric hybrids between Hb Footscray and Hb A.

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Hb Howick or beta 37(C3) Trp-->Gly is a newly described hemoglobin variant found in an adult male. Hematological data and stability by the isopropanol stability test were normal. The abnormal variant comprised 29% of total hemoglobin and migrated in the Hb D position on cellulose acetate at pH 8.6, and in the Hb F position on citrate agar (pH 6.0). Oxygen dissociation studies on the whole blood showed the variant to have a higher oxygen affinity than normal, with a P50 of 19.8 mm Hg (normal, 26 mm Hg). There were also significant differences in the saturation curve. The variant showed a reduced Bohr effect which was manifested as very high oxygen affinity at low pH and saturation. The beta 37 residue is an alpha 1 beta 2 contact site and the substitution of the tryptophan for a glycine would be expected to result in a destabilization of the deoxy-hemoglobin form because of the reduced number of hydrogen bonds, salt bridges and van der Waal contacts between the alpha 1 and beta 2 chains.

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A competitive ELISA for lipoprotein(a) (Lp(a)) is described. The method uses a commercially available polyclonal anti-Lp(a) antibody and an IgG biotinstreptavidin-horseradish peroxidase detection system. The method is simple and robust with an assay sensitivity of 0.7 ng/well (1.4 micrograms/l). The antibody cross-reactivity was 0.14% against LDL and 0.70% against plasminogen. The coefficients of variation obtained with control sera of 266 and 552 mg/l were: 5.0% and 4.6% (n = 6), respectively for the intraassay; and 10.8% and 9.5% (n = 16), respectively for the interassay. The method showed an excellent correlation with a commercial immunoradiometric assay (IRMA), y (ELISA) = 0.94x (IRMA) - 8, (r = 0.98). A recovery study in which a 200 mg/L standard and four plasma samples were diluted with different proportions of a low plasma sample, gave linear relationships and also confirmed the specificity of the antibody.

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The heparin affinity of normal and two P1 variants of antithrombin-III (AT) was studied by gradient elution with NaCl in Tris buffer on heparin-Sepharose. At pH 7.4 normal AT eluted at [Na+] 0.78 mol/l and the variants both showed increased affinity with AT Pescara eluting at [Na+] 0.86 mol/l and AT Glasgow at [Na+] 0.92 mol/l. We have earlier proposed a model for heparin activation in which the native state of AT maintains a salt bridge involving the P1 Arg-393 residue. Binding of heparin induces a higher heparin affinity conformation in which the salt bridge is disrupted to reveal the reactive centre for inhibition of thrombin. The Glasgow and Pescara variants, lacking a reactive centre P1 basic residue, would be unable to form this salt bridge, and we suggested that the high affinity conformation which they adopt as their native state would resemble the heparin induced conformation. To examine this model, we measured the heparin induced fluorescence of two P1 variants and tested the susceptibility of their reactive loops to catalytic cleavage. Both variants had fluorescence spectra indistinguishable from normal AT. In the absence of heparin, neither variant was more susceptible than normal to catalytic cleavage by human neutrophil elastase. These findings suggest that the conformation of these P1 variants is different to that of fully heparinized normal AT.

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