A PETase enzyme synthesised in the chloroplast of the microalga Chlamydomonas reinhardtii is active against post-consumer plastics

Polyethylene terephthalate hydrolases (PETases) are a newly discovered and industrially important class of enzymes that catalyze the enzymatic degradation of polyethylene terephatalate (PET), one of the most abundant plastics in the world. The greater enzymatic efficiencies of PETases compared to close relatives from the cutinase and lipase families have resulted in increasing research interest. Despite this, further characterization of PETases is essential, particularly regarding their possible activity against other kinds of plastic. In this study, we exploited for the first time the use of the microalgal chloroplast for more sustainable synthesis of a PETase enzyme. A photosynthetic-restoration strategy was used to generate a marker-free transformant line of the green microalga Chlamydomonas reinhardtii in which the PETase from Ideonella sakaiensis was constitutively expressed in the chloroplast. Subsequently, the activity of the PETase against both PET and post-consumer plastics was investigated via atomic force microscopy, revealing evidence of degradation of the plastics.

Worm globalization

We report the first case of eosinophilic pleural effusion due to Anisakis spp. infection in a 39-years-old European subject hospitalized for worsening dyspnoea and abdominal and thoracic pain. Lung CT scan showed bilateral pleural effusion; thoracentesis revealed significant eosinophilia (45%), with normal eosinophils in the blood. Microbiological tests on pleural effusion were negative for bacteria, SARS-CoV-2, tuberculosis, fungi and parasites. The patient used to eat raw fish; Western blot was positive for Anisakis spp. in blood and pleural effusion. In the era of globalization, unusual parasitic infections should be considered also in nonendemic countries, especially in patients with unexplained eosinophilia.

Parvimonas micra a new potential pathogen in hospitalized patients: a case series from 2015-2022

Parvimonas micra isolations are usually part of polymicrobial infections and the pathogenic role of this microrganism is still debated. We describe here a large series of hospitalized patients diagnosed with Parvimonas micra infections and discuss the clinical and therapeutic management and the outcome of these infections.

A case of spondylodiscitis by Ureaplasma urealyticum in an immunocompetent adult with spine stabilization

Ureaplasma urealyticum is part of the normal genital flora of many sexually experienced people, thereby it is mostly associated with genitourinary tract infections. Here, we present the first case reported in literature of a spondylodiscitis caused by Ureaplasma urealyticum in an immunocompetent 62-years-old subject. Ureaplasma urealyticum was detected through broad-range bacterial polymerase chain reaction in all samples obtained by T11 bone biopsy, whilst cultures were all negative. Due to the technical difficulties in removing the spinal osteo-synthesis devices, no neurosurgical intervention was planned, therefore a suppressive therapy with moxifloxacin was administered. After seven months, the patient underwent to T10-11 partial vertebrectomy, insertion of an expandable cage at that level, substitution of T11 screws and prolongation of stabilization from T6 to ilium due to a fracture of T11 and T12; the remaining spinal osteo-synthesis material was not removed. A computed tomography (CT) scan of the spine did not show features compatible with spondylodiscitis. Moxifloxacin was stopped after 15 months without any recurrence of Ureaplasma urealyticum infection. Our case highlights the importance in considering Ureaplasma urealyticum as a potential etiological germ in culture-negative spondylodiscitis.

A cytokine/PTX3 prognostic index as a predictor of mortality in sepsis

Background

Early prognostic stratification of patients with sepsis is a difficult clinical challenge. Aim of this study was to evaluate novel molecules in association with clinical parameters as predictors of 90-days mortality in patients admitted with sepsis at Humanitas Research Hospital.

Methods

Plasma samples were collected from 178 patients, diagnosed based on Sepsis-3 criteria, at admission to the Emergency Department and after 5 days of hospitalization. Levels of pentraxin 3 (PTX3), soluble IL-1 type 2 receptor (sIL-1R2), and of a panel of pro- and anti-inflammatory cytokines were measured by ELISA. Cox proportional-hazard models were used to evaluate predictors of 90-days mortality.

Results

Circulating levels of PTX3, sIL-1R2, IL-1β, IL-6, IL-8, IL-10, IL-18, IL-1ra, TNF-α increased significantly in sepsis patients on admission, with the highest levels measured in shock patients, and correlated with SOFA score (PTX3: r=0.44, p<0.0001; sIL-1R2: r=0.35, p<0.0001), as well as with 90-days mortality. After 5 days of hospitalization, PTX3 and cytokines, but not sIL-1R2 levels, decreased significantly, in parallel with a general improvement of clinical parameters. The combination of age, blood urea nitrogen, PTX3, IL-6 and IL-18, defined a prognostic index predicting 90-days mortality in Sepsis-3 patients and showing better apparent discrimination capacity than the SOFA score (AUC=0.863, 95% CI: 0.780−0.945 vs. AUC=0.727, 95% CI: 0.613-0.840; p=0.021 respectively).

Conclusion

These data suggest that a prognostic index based on selected cytokines, PTX3 and clinical parameters, and hence easily adoptable in clinical practice, performs in predicting 90-days mortality better than SOFA. An independent validation is required.

Activity and substrate specificity of lytic polysaccharide monooxygenases: An ATR FTIR-based sensitive assay tested on a novel species from Pseudomonas putida

Pseudomonas putida W619 is a soil Gram-negative bacterium commonly used in environmental studies thanks to its ability in degrading many aromatic compounds. Its genome contains several putative carbohydrate-active enzymes such as glycoside hydrolases and lytic polysaccharide monooxygenases (PMOs). In this study, we have heterologously produced in Escherichia coli and characterized a new enzyme belonging to the AA10 family, named PpAA10 (Uniprot: B1J2U9), which contains a chitin-binding type-4 module and showed activity toward β-chitin. The active form of the enzyme was produced in E. coli exploiting the addition of a cleavable N-terminal His tag which ensured the presence of the copper-coordinating His as the first residue. Electron paramagnetic resonance spectroscopy showed signal signatures similar to those observed for the copper-binding site of chitin-cleaving PMOs. The protein was used to develop a versatile, highly sensitive, cost-effective and easy-to-apply method to detect PMO's activity exploiting attenuated total reflection-Fourier transform infrared spectroscopy and able to easily discriminate between different substrates.

Further acquisitions on gonadal function in bromocriptine treated hyperprolactinemic male patients

The diurnal variation of plasma total and free testosterone (tT and fT) and the gonadotropinemic response to LH-RH were evaluated in a group of hyperprolactinemic impotent males with pituitary microprolactinoma before and during therapy with bromocriptine, a well known dopamine agonist drug. Before treatment, basal levels not only of tT but also of fT were decreased and the diurnal variation of both tT and fT was absent. Moreover, the LH-RH test showed a delay in the LH response peak, together with normal basal levels of LH. Bromocriptine therapy caused normalization of both the secretion response of LH to LH-RH and of the secretion pattern of tT and of fT (basal levels and diurnal variation) besides a significant decrease in PRL levels and an improvement in sexual function. The possible effects of high plasma levels of PRL at various levels of the hypothalamus-pituitary-testicular axis are discussed.