Patulin Detoxification by Recombinant Manganese Peroxidase from Moniliophthora roreri Expressed by Pichia pastoris

The fungal secondary metabolite patulin is a mycotoxin widespread in foods and beverages which poses a serious threat to human health. However, no enzyme was known to be able to degrade this mycotoxin. For the first time, we discovered that a manganese peroxidase (MrMnP) from Moniliophthora roreri can efficiently degrade patulin. The MrMnP gene was cloned into pPICZα(A) and then the recombinant plasmid was transformed into Pichia pastoris X-33. The recombinant strain produced extracellular manganese peroxidase with an activity of up to 3659.5 U/L. The manganese peroxidase MrMnP was able to rapidly degrade patulin, with hydroascladiol appearing as a main degradation product. Five mg/L of pure patulin were completely degraded within 5 h. Moreover, up to 95% of the toxin was eliminated in a simulated patulin-contaminated apple juice after 24 h. Using Escherichia coli as a model, it was demonstrated that the deconstruction of patulin led to detoxification. Collectively, these traits make MrMnP an intriguing candidate useful in enzymatic detoxification of patulin in foods and beverages.     

Molecular alterations in pediatric brainstem gliomas

1 Background

Diffuse intrinsic pontine gliomas (DIPGs) have a dismal prognosis. Previously, diagnosis was based on a typical clinical presentation and magnetic resonance imaging findings. After the start of the era of biopsies, DIPGs bearing H3 K27 mutations have been reclassified into a novel entity, diffuse midline glioma, based on the presence of this molecular alteration. However, it is not well established how clinically diagnosed DIPG overlap with H3 K27‐mutated diffuse midline gliomas, and whether rare long‐term survivors also belong to this group.

2 Methods

We studied tumor samples obtained at diagnosis or upon autopsy from 23 children, including two long‐term survivors. Based on clinical, radiological, and histological findings, all tumors were previously diagnosed as DIPGs. All samples were analyzed for genetic alterations by next‐generation sequencing (NGS) and for protein expression by immunohistochemistry (IHC).

3 Results

H3 K27 was mutated in NGS or IHC in 20 patients, excluding both long‐term survivors. One of these long‐term survivors harbored a mutation in IDH1, formerly considered to be an alteration absent in pediatric diffuse brainstem gliomas. Other altered genes in NGS included TP53 (10 patients), MET and PDGFRA (3 patients each), VEGFR and SMARCA4 (2 patients each), and PPARγ, PTEN and EGFR in 1 patient, respectively. IHC revealed cMYC expression in 15 of 24 (63%) of all samples, exclusively in the biopsies.

4 Conclusions

Eighty‐seven percent of the tumors formerly diagnosed as DIPGs could be reclassified as H3 K27‐mutated diffuse midline gliomas. Both long‐term survivors lacked this alteration. Contrary to former conceptions, IDH1 mutations may occur also in pediatric brainstem gliomas.     

Integration of ER protein quality control mechanisms defines β cell function and ER architecture

Three principal ER quality-control mechanisms, namely, the unfolded protein response, ER-associated degradation (ERAD), and ER-phagy are each important for the maintenance of ER homeostasis, yet how they are integrated to regulate ER homeostasis and organellar architecture in vivo is largely unclear. Here we report intricate crosstalk among the 3 pathways, centered around the SEL1L-HRD1 protein complex of ERAD, in the regulation of organellar organization in β cells. SEL1L-HRD1 ERAD deficiency in β cells triggers activation of autophagy, at least in part, via IRE1α (an endogenous ERAD substrate). In the absence of functional SEL1L-HRD1 ERAD, proinsulin is retained in the ER as high molecular weight conformers, which are subsequently cleared via ER-phagy. A combined loss of both SEL1L and autophagy in β cells leads to diabetes in mice shortly after weaning, with premature death by approximately 11 weeks of age, associated with marked ER retention of proinsulin and β cell loss. Using focused ion beam scanning electron microscopy powered by deep-learning automated image segmentation and 3D reconstruction, our data demonstrate a profound organellar restructuring with a massive expansion of ER volume and network in β cells lacking both SEL1L and autophagy. These data reveal at an unprecedented detail the intimate crosstalk among the 3 ER quality-control mechanisms in the dynamic regulation of organellar architecture and β cell function.     

A rare case of metastatic pancreatic adenocarcinoma presenting as a pulmonary embolism from nonbacterial thrombotic endocarditis

Nonbacterial thrombotic endocarditis (NBTE) also called, "Marantic endocarditis" occurs due to an underlying hypercoagulable state causing tissue damage and upregulation of the coagulation cascade, with noninfective vegetation formation on heart valves. Mitral and aortic valves are most commonly involved. NBTE is rare, with an incidence of 1.6%, with 65 cases identified during a 10-year autopsy analysis. The most common malignancies associated with NBTE include gynecological cancers, lung cancer, gastric cancer, and pancreatic cancers with adenocarcinoma histology being the greatest risk. Herein, we present a rare case of a 55-year-old male who presented with acute hypoxic respiratory failure secondary to pulmonary embolism due to nonbacterial thrombotic endocarditis. He was found to have advanced pancreatic adenocarcinoma on further investigation of the 2.2 cm hypodense cystic mass in the distal pancreatic body and tail, and complex liver masses which were incidentally found on computed tomography angiography (CTA) of the chest. This is a rare phenomenon and clinicians have to consider the hypercoagulable state associated with cancers, particularly pancreatic adenocarcinoma, and the risk of NBTE.     

Dental fear affects adolescent perception of interaction with dental staff

The main purpose of this study was to explore whether subjective perception of interaction with dental staff is associated with dental fear in a population‐based sample of 18‐yr‐old adolescents (n = 773). The interaction was measured using the Patient Dental Staff Interaction Questionnaire (PDSIQ), validated with exploratory and confirmatory factor analyses, which yielded the factors of ‘kind atmosphere and mutual communication’, ‘roughness’, ‘insecurity’, ‘trust and safety’, and ‘shame and guilt’. Dental fear was measured using the Modified Dental Anxiety Scale (MDAS). Gender and sense of coherence (SOC) were included as potential confounding variables. Adolescents with high dental fear more often perceived their interaction with dental staff negatively and more often felt insecure than others. This difference persisted after adjustment for gender and SOC. In conclusion, adolescents with high dental fear may perceive their interaction with dental staff more positively if the staff succeed in creating a positive, trusting, approving, and supportive atmosphere with kindness, calmness, and patience. The communication and interaction skills of dental staff may play a particularly important role when encountering highly fearful dental patients.