Post-harvest conservation of chestnut (cv. Martaínha), comparison of two controlled atmospheres during 60 days

According to Instituto Nacional de Estatística, during 2021, Portugal produced 38 thousand tons of chestnuts. The northern region of mainland Portugal is the largest concentration of chestnut trees is found and accounts for about 88% of the volume of national production. Portugal is the seventh-largest producer of chestnuts globally, although this value only represents approximately 2% of world production1. The quality parameters of chestnut are defined by colour, flavour and texture; however, this optimal status is only maintained for a short period of time. Chestnuts have a high moisture value that is quickly lost during conservation compared to other nuts. The significant factors in post-harvest depreciation are moulding or rotting caused by larval development of insects on the tree and later by fungi. Infections often start in the larval galleries of insec ts by the contact of the fruits with the ground before picking.Projeto CULTIVAR (CENTRO-01-0145-FEDER-000020)info:eu-repo/semantics/publishedVersio

Immobilization of L-asparaginase towards surface-modified carbon nanotubes

L-asparaginase (ASNase, EC 3.5.1.1) is an enzyme that catalyzes L-asparagine hydrolysis into L-aspartic acid and ammonia and is mainly applied in pharmaceutical and food industries [1]. The ASNase currently commercialized for pharmaceutical purposes is produced from two main bacterial sources: recombinant Escherichia coli and Erwinia chrysanthemi. However, some disadvantages are associated with its free form, such as the shorter half-life [2]. Immobilization of ASNase has been proposed as an efficient approach to overcome this limitation [3]. In this work, a straightforward method, including the functionalization of multi-walled carbon nanotubes (MWCNTs) through a hydrothermal oxidation treatment with nitric acid, and the immobilization of ASNase by adsorption over pristine and modified MWCNTs was investigated. Different operation conditions, including pH, contact time, ASNase/MWCNT mass ratio, and the operational stability of the immobilized ASNase were evaluated. The characterization of the ASNase-MWCNT bioconjugate was addressed using different techniques, namely Transmission Electron Microscopy (TEM), Thermogravimetric analysis (TGA), and Raman spectroscopy. Functionalized MWCNTs showed promising results, with an immobilization yield and a relative recovered activity of commercial ASNase above 95%, under the optimized adsorption conditions (pH 8, 60 min of contact and 1.5´10–3 g.mL-1of ASNase). The ASNase-MWCNT bioconjugate also showed improved enzyme operational stability (6 consecutive reaction cycles without activity loss), proving its suitability for application in industrial processes.publishe

Immobilization of L-asparaginase towards surface-modified carbon nanotubes

L-asparaginase (LA) is an enzyme that catalyzes L-asparagine hydrolysis into L-aspartic acid and ammonia and is mainly applied in pharmaceutical and food industries. The LA currently commercialized for pharmaceutical purposes is produced from two main bacterial sources: recombinant Escherichia coli and Erwinia chrysanthemi. However, some disadvantages are associated with its free form, such as the shorter half-life. Immobilization of LA has been proposed as an efficient approach to overcome this limitation. In this work, a straightforward method, including the functionalization of multi-walled carbon nanotubes (MWCNTs) through a hydrothermal oxidation treatment and the immobilization of LA by adsorption over pristine and modified MWCNTs was investigated. Different operation conditions, including pH, contact time, ASNase/MWCNT mass ratio, and the operational stability of the immobilized LA, were evaluated. The characterization of the LA-MWCNT bioconjugate was addressed using different techniques, namely Transmission Electron Microscopy (TEM), Thermogravimetric analysis (TGA), and Raman spectroscopy. Functionalized MWCNTs showed promising results, with an immobilization yield and a relative recovered activity of commercial LA above 95%, under the optimized adsorption conditions (pH 8, 60 min of contact, and 1.510–3 g.mL-1 of LA). The LA-MWCNT bioconjugate also showed improved enzyme operational stability (6 consecutive reaction cycles without activity loss), proving its suitability for application in industrial processes.publishe

Pristine carbon nanotubes for an efficient L-asparaginase immobilization

The enzyme L-asparaginase (ASNase) presents effective antineoplastic properties for acute lymphoblastic leukemia treatment, besides their potential use in the food sector to decrease acrylamide formation. Considering their applications, the improvement of these enzyme properties by efficient immobilization techniques is in high demand. Carbon nanotubes are promising enzyme immobilization supports since these materials have increased surface area and effective capacity for enzyme loading. Accordingly, in this study, multi-walled carbon nanotubes (MWCNTs) were explored as novel supports for ASNase immobilization by a simple adsorption method. The effect of pH, the contact time of immobilization, and the ASNase to nanoparticles mass ratio were optimized according to the enzyme immobilization yield and relative recovered activity. The enzyme-MWCNTs bioconjugation was confirmed by thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), and transmission electron microscopy (TEM) studies. MWCNTs have a high ASNase loading capacity, with a maximum immobilization yield of 90%. The adsorbed ASNase retains 90% of the initial enzyme activity at the optimized conditions (pH 8, 60 min, and 1.5×10-3 g.mL-1 of ASNase). According to these results, ASNase immobilized onto MWCNTs can find in several areas improved applications, namely biosensors, medicine, and the food industry.publishe

An Innovative Photoreactor, FluHelik, To Promote UVC/H2O2 Photochemical Reactions: Tertiary Treatment of an Urban Wastewater

This is the accepted manuscript of the following article: Espíndola et al. Science of the Total Environment, 2019, 667, 197-207. https://doi.org/10.1016/j.scitotenv.2019.02.335An innovative photoreactor, FluHelik, was used to promote the degradation of contaminants of emerging concern (CECs) by a photochemical UVC/H2O2 process. First, the system was optimized for the oxidation of a model antibiotic, oxytetracycline (OTC), using both ultrapure water (UPW) and a real urban wastewater (UWW) (collected after secondary treatment) as solution matrices. Following, the process was evaluated for the treatment of a UWW spiked with a mixture of OTC and 10 different pharmaceuticals established by the Swiss legislation at residual concentrations (∑CECs <660 μg L−1). The performance of the FluHelik reactor was analyzed both at lab and pre-pilot scale in multiple and single pass flow modes. The efficiency of the FluHelik photoreactor, at lab-scale, was evaluated at different operational conditions (H2O2 concentration, UVC lamp power (4, 6 and 11 W) and flow rate) and further compared with a conventional Jets photoreactor. Both photoreactors exhibited similar OTC removal efficiencies at the best conditions; however, the FluHelik reactor showed to be more efficient (1.3 times) in terms of mineralization when compared with the Jets reactor. Additionally, the efficiency of the UVC/H2O2 photochemical system using the FluHelik photoreactor in reducing the toxicity of the real effluent containing 11 pharmaceuticals was evaluated through zebrafish (Danio rerio) embryo toxicity bioassays. FluHelik scale-up from laboratory to pre-pilot to promote UVC/H2O2 photochemical process proved to be feasibleThis work was financially supported by: Associate Laboratory LSRE-LCM - UID/EQU/50020/2019 - funded by national funds through FCT/MCTES (PIDDAC). V.J.P. Vilar acknowledges the FCT Investigator 2013 Programme (IF/00273/2013). J.C.A. Espíndola acknowledges CNPq (Brazil) for his scholarship (205781/2014-4). R. Montes, R. Rodil and J.B. Quintana acknowledge the financial support of Spanish "Agencia Estatal de Investigación" (ref. CTM2017-84763-C3-R-2) and Xunta de Galicia (ref. ED431C2017/36), both confounded by FEDER/ERDFS

Clinical and Epidemiological Features of Hospitalized and Ambulatory Patients with Human Monkeypox Infection: A Retrospective Observational Study in Portugal

Monkeypox, a neglected and re-emergent zoonotic disease caused by monkeypox virus (MPXV) infection, has been endemic in Central and Western Africa for decades. More recently, an outbreak has spread to a global level, occurring in sites with no previous reported cases and being clustered among men who have sex with men, suggesting new modes of transmission. There is an urgent need for research for a better understanding of the genomic evolution and changing epidemiology of the Orthopoxvirus group. Our work aimed to characterize the clinical and epidemiological features of a cohort of patients with MPXV infection in a Portuguese hospital, admitted between 5 May and 26 July 2022. In this retrospective observational study, aggregate data of a case series on the presentation, clinical course, and outcomes of confirmed MPXV infections are reported. The study included 40 men and 1 woman, with a mean age of 37.2 years old; 92.7% identified as men who have sex with men, 90.2% had unprotected sex or sex with multiple or anonymous partners in the previous month, and 39.0% reported to have had sex with an MPXV-confirmed case; 59.5% had previously known human immunodeficiency virus (HIV) infection, all of whom were under antiretroviral therapy, and no patients had acquired immunodeficiency syndrome (AIDS) criteria. About a quarter of patients were observed only a week after symptom onset. All patients had skin or mucosal lesions and the anogenital region was the most frequent lesion site. There were no statistically significant clinical differences between HIV-positive and negative individuals. Four patients were admitted to the inpatient clinic, two of whom had proctitis with difficult-to-manage anal pain. There were no reported deaths. Our findings suggest the sexual route as a relevant mode of transmission of MPXV and confirm the mostly benign presentation of this disease.info:eu-repo/semantics/publishedVersio

Superior operational stability of immobilized L-asparaginase over surface-modified carbon nanotubes

L-asparaginase (ASNase, EC 3.5.1.1) is an enzyme that catalyzes the L-asparagine hydrolysis into L-aspartic acid and ammonia, being mainly applied in pharmaceutical and food industries. However, some disadvantages are associated with its free form, such as the ASNase short half-life, which may be overcome by enzyme immobilization. In this work, the immobilization of ASNase by adsorption over pristine and modified multi-walled carbon nanotubes (MWCNTs) was investigated, the latter corresponding to functionalized MWCNTs through a hydrothermal oxidation treatment. Different operating conditions, including pH, contact time and ASNase/MWCNT mass ratio, as well as the operational stability of the immobilized ASNase, were evaluated. For comparison purposes, data regarding the ASNase immobilization with pristine MWCNT was detailed. The characterization of the ASNase-MWCNT bioconjugate was addressed using different techniques, namely Transmission Electron Microscopy (TEM), Thermogravimetric Analysis (TGA) and Raman spectroscopy. Functionalized MWCNTs showed promising results, with an immobilization yield and a relative recovered activity of commercial ASNase above 95% under the optimized adsorption conditions (pH 8, 60 min of contact and 1.5 × 10-3 g mL-1 of ASNase). The ASNase-MWCNT bioconjugate also showed improved enzyme operational stability (6 consecutive reaction cycles without activity loss), paving the way for its use in industrial processes.publishe

Molecular detection of Leishmania infantum, filariae and Wolbachia spp. in dogs from southern Portugal

Background: Leishmaniosis caused by the protozoan Leishmania infantum and dirofilariosis caused by the nematodes Dirofilaria immitis or Dirofilaria repens are vector-borne zoonoses widely present in the Mediterranean basin. In addition, some studies reported that the endosymbiont Wolbachia spp. play a role in the biology and pathogenesis of filarial parasites. The aim of this work was to evaluate the frequency of mono-and co-infections by L. infantum, filariae and Wolbachia spp. and their association with clinical signs in dogs from the south of Portugal. Leishmanial, filarial and Wolbachia spp. DNA were evaluated by specific real-time polymerase chain reaction (qPCR) assays in blood samples from 230 dogs.Findings: One hundred and thirty-nine (60.4 %) dogs were qPCR-positive for L. infantum and 26 (11.3 %) for filariae (24 for D. immitis only, one D. immitis and for Acanthocheilonema dracunculoides and another one for Acanthocheilonema reconditum only). Wolbachia spp. DNA was amplified from 16 (64.0 %) out of the 25 D. immitis-positive dogs. Nineteen (8.3 %) dogs were co-infected with L. infantum and D. immitis, including the one (0.4 %) A. drancunculoides-positive animal. In dogs without clinical signs consistent with leishmaniosis and/or dirofilariosis, L. infantum prevalence was 69 %, whereas in those dogs with at least one clinical manifestation compatible with any of the two parasitoses prevalence was 42.7 %. Leishmania prevalence was significantly higher in apparently healthy mongrels (77.2 %) and pets (76.9 %) than in defined-breed dogs (including crosses; 58.8 %) and in dogs with an aptitude other than pet (i.e. farm, guard, hunting, shepherd or stray), respectively, whereas in those dogs with at least one clinical sign, the detection of L. infantum DNA was higher in males (53.3 %) and in those dogs not receiving insect repellents (52.8 %).Conclusions: The molecular detection of canine vector-borne disease (CVBD) agents, some of which are zoonotic, reinforces the need to implement efficient prophylactic measures, such as insect repellents and macrocyclic lactones (including compliance to administration), in the geographical areas where these agents are distributed, with the view to prevent infection and disease among mammalian hosts including humans