Isolation and characterization of a strain of Lichtheimia corymbifera (ex Absidia corymbifera) from a case of bovine abortion

<p>Abstract</p> <p>Background</p> <p>Lichtheimia corymbifera (previously Absidia corymbifera) is a filamentous zygomycetes belonging to the order Mucorales and to the family Lichtheimiaceae. Members of genus Lichtheimia spp. are cosmopolitan and ubiquitous in nature. Lichtheimia corymbifera is a recognized agent of diseases in man and animals. In cattle it causes abortion and mastitis. Three cases of bovine abortion occurred in a herd located in the Po Valley. Serological examinations were performed on fetal and mother's blood. One of the aborted fetus was referred to our laboratory. The paper describes the isolation and characterization of Lichtheimia corymbifera from a bovine aborted fetus.</p> <p>Methods</p> <p>Serological examinations were performed on fetal and mother's blood. Lesions on fetal tissues and placenta leaded the diagnostic suspect towards a mycotic aetiology. Tissues were then put in culture, and at the same time an histological examination was performed, together with bacteriological and virological tests. The isolate from placenta and fetal tissues was identified and characterized by PCR and RFLP, using the ITS region as a target sequence and AclI restriction site within the amplicon to distinguish Lichtheimia corymbifera among the other fungi.</p> <p>Results</p> <p>Serological, bacteriological and virological tests gave aspecific results. Histological examination evidenced numerous PAS positive hyphae within the necrotic cotiledons and numerous fungal nonseptate hyphae to the GMS stain. Colonies with typical morphological features of fungi grew up on Sabouraud agar from fetal skin and placenta. On the developed colonies the microscopic examination has shown a large number of nonseptate hyphae and sporangia consistent with Mucorales. PCR and RFLP allowed the identification of the isolate as Lichtheimia corymbifera.</p> <p>Conclusion</p> <p>The present report describes the isolation and the molecular characterisation of a fungal isolate from bovine aborted fetus and placenta. The diagnostic protocol allowed to identify and characterise the strain. This is the first isolation in Italy of Lichtheimia corymbifera in a bovine aborted fetus.</p

Axonopathy in the central nervous system is the hallmark of mice with a novel intragenic null mutation of dystonin.

Dystonia musculorum is a neurodegenerative disorder caused by a mutation in the dystonin gene. It has been described in mice and humans where it is called hereditary sensory autonomic neuropathy. Mutated mice show severe movement disorders and die at the age of 3-4 weeks. This study describes the discovery and molecular, clinical, as well as pathological characterization of a new spontaneously occurring mutation in the dystonin gene in C57BL/6N mice. The mutation represents a 40-kb intragenic deletion allele of the dystonin gene on chromosome 1 with exactly defined deletion borders. It was demonstrated by Western blot, mass spectrometry, and immunohistology that mice with a homozygous mutation were entirely devoid of the dystonin protein. Pathomorphological lesions were restricted to the brain stem and spinal cord and consisted of swollen, argyrophilic axons and dilated myelin sheaths in the white matter and, less frequently, total chromatolysis of neurons in the gray matter. Axonal damage was detected by amyloid precursor protein and nonphosphorylated neurofilament immunohistology. Axonopathy in the central nervous system (CNS) represents the hallmark of this disease. Mice with the dystonin mutation also showed suppurative inflammation in the respiratory tract, presumably due to brain stem lesion-associated food aspiration, whereas skeletal muscles showed no pathomorphological changes. This study describes a novel mutation in the dystonin gene in mice leading to axonopathy in the CNS. In further studies, this model may provide new insights into the pathogenesis of neurodegenerative diseases and may elucidate the complex interactions of dystonin with various other cellular proteins especially in the CNS

MEK1/2 regulate normal BCR and ABL1 tumor-suppressor functions to dictate ATO response in TKI-resistant Ph+ leukemia

Resistance to tyrosine kinase inhibitors (TKIs) remains a clinical challenge in Ph-positive variants of chronic myeloid leukemia. We provide mechanistic insights into a previously undisclosed MEK1/2/BCR::ABL1/BCR/ABL1-driven signaling loop that may determine the efficacy of arsenic trioxide (ATO) in TKI-resistant leukemic patients. We find that activated MEK1/2 assemble into a pentameric complex with BCR::ABL1, BCR and ABL1 to induce phosphorylation of BCR and BCR::ABL1 at Tyr360 and Tyr177, and ABL1, at Thr735 and Tyr412 residues thus provoking loss of BCR's tumor-suppression functions, enhanced oncogenic activity of BCR::ABL1, cytoplasmic retention of ABL1 and consequently drug resistance. Coherently, pharmacological blockade of MEK1/2 induces dissociation of the pentameric MEK1/2/BCR::ABL1/BCR/ABL1 complex and causes a concurrent BCRY360/Y177, BCR::ABL1(Y360/Y177) and cytoplasmic ABL1(Y412/T735) dephosphorylation thereby provoking the rescue of the BCR's anti-oncogenic activities, nuclear accumulation of ABL1 with tumor-suppressive functions and consequently, growth inhibition of the leukemic cells and an ATO sensitization via BCR-MYC and ABL1-p73 signaling axes activation. Additionally, the allosteric activation of nuclear ABL1 was consistently found to enhance the anti-leukemic effects of the MEK1/2 inhibitor Mirdametinib, which when combined with ATO, significantly prolonged the survival of mice bearing BCR::ABL1-T315I-induced leukemia. These findings highlight the therapeutic potential of MEK1/2-inhibitors/ATO combination for the treatment of TKI-resistant leukemia

Prevalenza e antibiotico-sensibilità di Mannheimia haemolytica isolata da focolai di malattia respiratoria in allevamenti bovini da latte del Nord Italia

Introduction - At present, Mannheimia haemolytica (M.h.) is recognized to be the major bacterial pathogen involved in Bovine Respiratory Disease (BRD) outbreaks. Aim - The study is aimed at providing information on the prevalence of Mannheimia haemolytica, alone or in association with other pathogens, during Bovine Respiratory Disease (BRD) outbreaks involving dairy calves. Mannheimia haemolytica isolates were submitted to assessment of sensitivity to antibiotics widely used in buiatrics. Materials and methods - During 2012-2016, 185 acute respiratory disease outbreaks involving dairy cattle operations located in the Po Valley (Italy) were examined. From calves aged 10-180 days, 715 nasal swabs from animals showing acute respiratory signs and 66 respiratory tracts from died calves belonging to 39 BRD outbreaks were collected and submitted to laboratory investigations at detecting viral and bacterial respiratory pathogens. M.h. isolates were tested for their antimicrobial susceptibility by Kirby-Bauer method. Results and discussion - Results confirm that BRSV is the main viral pathogen involved in BRD. Laboratory investigations on nasal swabs and lung specimens collected from calves with acute clinical signs of disease allowed the isolation of 136 Mannheimia haemolytica strains with a prevalence of 17% and 24% for nasal swabs and lung specimens, respectively. A level of susceptibility >75% to amoxicillin+clavulanic acid, ampicillin, ceftiofur, florfenicol, trimethoprim+sulfonamides was demonstrated. Conversely, a level of resistance >50% to sulfadiazine and tylosin was detected. Our results are in accordance with other surveys carried out in Northern Italy. Conversely, disagreement with European reports regarding antibiotic sensitivity of M.h. was observed. European data regarding amoxillin-clavulanic acid, thirdgeneration cephalosporins, florfenicol, and fluoroquinolones showed lower resistance than those emerging from our findings. This phenomenon is caused by the extensive use in our cattle operations of antibiotics in general and of the abovementioned antibiotic classes in particular. Conclusions - To limit the extensive use of antibiotics in BRD, preventive strategies should be carried out by using vaccines. For the control of M.h. - LKT pathogenic effect, monovalent and/or combo vaccines have long been available