Nanocatalytic performance of pectinase immobilized over in situ prepared magnetic nanoparticles.

Immobilization of enzymes is one of the protein engineering methods used to improve their thermal and long-term stabilities. Immobilized pectinase has become an essential biocatalyst for optimization in the food processing industry. Herein, nanostructured magnetic nanoparticles were prepared in situ for use as supports to immobilize pectinase. The structural, morphological, optical and magnetic features and the chemical compositions of the nanoparticles were characterized. Nanoparticle agglomeration and low porosity were observed due to the synthetic conditions. These nanoparticles exhibited superparamagnetic behavior, which is desirable for biotechnological applications. The maximum retention rate for the enzyme was observed at pH 4.5 with a value of 1179.3 U/mgNP (units per milligram of nanoparticle), which was equivalent to a 65.6% efficiency. The free and immobilized pectinase were affected by the pH and temperature. The long-term instability caused 40% and 32% decreases in the specific activities of the free and immobilized pectinase, respectively. The effects of immobilization were analyzed with kinetic and thermodynamic studies. These results indicated a significant affinity for the substrate, a decreased reaction rate, and improved thermal stability of the immobilized pectinase. The reusability of the immobilized pectinase was preserved effectively during cycling, with only a 21.2% decrease in activity observed from the first to the last use. Therefore, alternative magnetic nanoparticles are presented for immobilizing and maintaining the thermostability of pectinase.

Stent Evaluation for Expiratory Central Airway Collapse: Does the Type of Stent Really Matter?

BACKGROUND: Careful selection of patients with expiratory central airway collapse (ECAC) that may benefit from tracheobronchoplasty (TBP) can be aided by a short-term airway stent evaluation. This can be performed with either silicone Y-stents (SYSs) or uncovered self-expanding metallic airway-stents (USEMAS). No direct comparison has been made between these 2 stent types. METHODS: This was a small retrospective review of consecutive patients that underwent a stent evaluation. A propensity score was used to match patients in the USEMAS and SYS groups. Outcomes included complications, changes in the health-related quality-of-life (HR-QoL), and changes in exercise capacity. Baseline measurements were compared with those obtained during stent evaluation and after TBP. RESULTS: Forty-two patients with severe ECAC underwent USEMAS placement, while 18 patients had an SYS placed. Propensity score matching resulted in 13 matched SYS and USEMAS pairs. The SYS group had an increased rate of mucus plugging (38.5% vs. 0%, P <0.047). Although not statically significant, a clinical improvement was observed in HR-QoL and exercise capacity in the USEMAS group during stent placement. In patients who underwent TBP, both USEMAS and SYS groups had a statistically significant change in the Modified Medical Research Council Dyspnea Scale during stent evaluation and after TBP. CONCLUSION: In patients with severe ECAC, short-term evaluation with airway stents appears to be safe and improves respiratory symptoms, HR-QoL, and exercise capacity. The use of USEMAS led to a lower complication rate, a greater improvement in HR-QoL and exercise capacity, and appeared to better predict how the patients would respond to TBP.

Pleural Disease in Acute COVID-19 Pneumonia: A Single Center Retrospective Cohort Study.

BACKGROUND: Pleural diseases encompass pleural effusion and pneumothorax (PTX), both of which were uncommon in coronavirus disease of 2019 (COVID-19). We aimed to describe the frequency, characteristics, and main outcomes of these conditions in patients with COVID-19 pneumonia. METHODS: We performed a retrospective cohort analysis of inpatients with COVID-19 pneumonia between January 1, 2020 and January 1, 2022, at Beth Israel Deaconess Medical Center in Boston, Massachusetts. RESULTS: Among 4419 inpatients with COVID-19 pneumonia, 109 (2.5%) had concurrent pleural disease. Ninety-four (2.1%) had pleural effusion (50% seen on admission) and 15 (0.3%) had PTX, both with higher rates of underlying conditions such as heart failure, liver disease, kidney disease, and malignancy. A total of 28 (30%) pleural effusions were drained resulting in 32% being exudative, 43% pseudoexudative, and 25% transudative. Regarding PTX, 5 (33%) were spontaneous and 10 (67%) were due to barotrauma while on mechanical ventilation. We found that the presence of underlying lung disease was not associated with an increased risk of developing PTX. In addition, patients with pleural disease had a higher incidence of severe or critical illness as represented by intensive care unit admission and intubation, longer hospital and intensive care unit stay, and a higher mortality rate as compared with patients without the pleural disease. CONCLUSION: Pleural effusions and pneumothoraces are infrequent findings in patients admitted due to COVID-19 pneumonia, worsened outcomes in these patients likely reflect an interplay between the severity of inflammation and parenchymal injury due to COVID-19 disease and underlying comorbidities.

Very severe tungiasis in Amerindians in the Amazon lowland of Colombia: A case series.

BACKGROUND: Tungiasis is a parasitic skin disease caused by penetrating female sand fleas. By nature, tungiasis is a self-limiting infection. However, in endemic settings re-infection is the rule and parasite load gradually accumulates over time. Intensity of infection and degree of morbidity are closely related. METHODOLOGY/PRINCIPAL FINDINGS: This case series describes the medical history, the clinical pathology, the socio-economic and the environmental characteristics of very severe tungiasis in five patients living in traditional Amerindian communities in the Amazon lowland of Colombia. Patients had between 400 and 1,300 penetrated sand fleas. The feet were predominantly affected, but clusters of embedded sand fleas also occurred at the ankles, the knees, the elbows, the hands, the fingers and around the anus. The patients were partially or totally immobile. Patients 1 and 3 were cachectic, patient 2 presented severe malnutrition. Patient 3 needed a blood transfusion due to severe anemia. All patients showed a characteristic pattern of pre-existing medical conditions and culture-dependent behavior facilitating continuous re-infection. In all cases intradomiciliary transmission was very likely. CONCLUSION/SIGNIFICANCE: Although completely ignored in the literature, very severe tungiasis occurs in settings where patients do not have access to health care and are stricken in a web of pre-existing illness, poverty and neglect. If not treated, very severe tungiasis may end in a fatal disease course.

Compliance with compression therapy in primary chronic venous disease: Results from a tropical country.

OBJECTIVES: To describe compliance rates of compression therapy in a cohort of patients with chronic venous disease and also to describe frequent causes of non-compliance. METHODS: A total of 889 patients with primary chronic venous disease were prescribed compression therapy after being evaluated by vascular surgeons. Subjects had a first visit during which time compression therapy was prescribed in addition to a follow-up visit. Strength of compression, type, prescription duration, and reasons of non-compliance were queried at follow-up. RESULTS: Only 31.8% of the patients reported wearing compression therapy as prescribed, 31.4% reported wearing compression most days, 28.3% reported wearing compression intermittently, and 8.5% of the patients reported not wearing compression at all. The main reasons of non-compliance were: uncomfortable (49.4%), too difficult to put on (34.5%), skin problems (itching) (21.5%), and unattractive (19.8%). CONCLUSIONS: Compliance with compression therapy in chronic venous disease is still a subject of concern as most patients are not using compression therapy as prescribed.

Growth capacity of thermotolerant campylobacters in culture media supplemented with pig and cow blood

In this work 60 thermotolerant Campylobacter strains (37 C. jejuni and 23 C. coli) isolated from the cows, pigs, chickens and ducks (15 strains of each type of animal) were used to establish their growth capacity on media containing cow or swine blood as potential substitutes of sheep or horse blood. The growth capacity was assessed by viable counts on cow and swine blood media, using the modified Miles and Misra method. Campylobacter strains showed better growth in the media supplemented with pig or sheep blood than with cow blood. Thus, the use of pig blood could be a supplement for Campylobacter culture medium, when there was no availability of sheep or horse blood.

Na cidade de Iquitos (Região Amazônica do Peru), tanto o sangue de carneiro quanto o de eqüino, ambos recomendados como suplemento nos meios de cultura para Campylobacter, são difíceis de encontrar. No entanto, sangues de bovino e de suíno são de fácil disponibilidade. Por esta razão, 60 amostras de Campylobacter termotolerantes (37 C. jejuni e 23 C. coli) isoladas de bovinos, suínos, frangos e patos (15 amostras de cada animal) foram utilizadas para estabelecer sua capacidade de crescimento em meios de cultura contendo sangue de bovino ou de suíno como potenciais substitutos do sangue de carneiro ou de eqüino. A capacidade de crescimento foi estabelecida através da contagem de células viáveis utilizando o método de Miles e Misra modificado. Todas as amostras de Campylobacter mostraram melhor crescimento em meios suplementados com sangue de eqüino ou de suíno. Estes resultados permitem propor o uso de sangue de suíno como suplementos em meios de cultura para Campylobacter.

La sangre de cerdo y de vaca como substitutos de la sangre de oveja o de caballo en medios de cultivo para campylobacters termotolerantes / The pig's blood and cow's blood substitutes sheep or horse culture media for thermotolerant campylobacters

En la ciudad de Iquitos (ubicada en la Amazonía peruana), la sangre de oveja y de caballo, uno de los suplementos recomendados para los medios de cultivo de campylobacters termotolerantes, no son tan disponibles como la sangre de cerdo y de vaca. Por ello, se estudió la capacidad de crecimiento de 60 cepas de Campylobacter termotolerantes (37 C. jejuni y 23 C. coli), usando sangre de vaca y de cerdo como potenciales substitutos de la sangre de oveja o de caballo. Estas cepas fueron aisladas de vacas, cerdos, pollos y patos (15 cepas de cada tipo de animal). Recuentos viables fueron realizados empleando el método de Miles y Misra, modificado. Las cepas de Campylobacter mostraron mayor crecimiento en presencia de sangre de cerdo o de oveja que con sangre de vaca; por lo que se sugiere el uso de sangre de cerdo como un suplemento de los medios de cultivo para Campylobacter, cuando no existe disponibilidad de sangre de oveja o de caballo.

In Iquitos (capital city of the Peruvian Amazon), sheep and horse blood, one of the recommended supplements for thermo tolerant campylobacters in growing environments, are difficult to obtain in comparison to pig and cow blood. Therefore, the growing capacity of 60 thermo tolerant Campylobacter strains (37 C. jejuni and 23 C. coli) using cow and pig blood as potential substitutes for sheep or horse blood, was studied. The strains were isolated from cows, pigs, chickens and ducks (15 strains of each animal). Accountable measure were used applying a modified Miles and Misra method. Compylobacter strains showed better growth in presence of pig or sheep blood in comparison with cow blood, so, we suggest the use of pig blood as a supplemet in the Campylobacter growing environment, when there is no availability of sheep or horse blood.

Functional characterization of the Bradyrhizobium japonicum modA and modB genes involved in molybdenum transport.

A modABC gene cluster that encodes an ABC-type, high-affinity molybdate transporter from Bradyrhizobium japonicum has been isolated and characterized. B. japonicum modA and modB mutant strains were unable to grow aerobically or anaerobically with nitrate as nitrogen source or as respiratory substrate, respectively, and lacked nitrate reductase activity. The nitrogen-fixing ability of the mod mutants in symbiotic association with soybean plants grown in a Mo-deficient mineral solution was severely impaired. Addition of molybdate to the bacterial growth medium or to the plant mineral solution fully restored the wild-type phenotype. Because the amount of molybdate required for suppression of the mutant phenotype either under free-living or under symbiotic conditions was dependent on sulphate concentration, it is likely that a sulphate transporter is also involved in Mo uptake in B. japonicum. The promoter region of the modABC genes has been characterized by primer extension. Reverse transcription and expression of a transcriptional fusion, P(modA)-lacZ, was detected only in a B. japonicum modA mutant grown in a medium without molybdate supplementation. These findings indicate that transcription of the B. japonicum modABC genes is repressed by molybdate.

The Bradyrhizobium japonicum napEDABC genes encoding the periplasmic nitrate reductase are essential for nitrate respiration.

The napEDABC gene cluster that encodes the periplasmic nitrate reductase from Bradyrhizobium japonicum USDA110 has been isolated and characterized. napA encodes the catalytic subunit, and the napB and napC gene products are predicted to be a soluble dihaem c and a membrane-anchored tetrahaem c-type cytochrome, respectively. napE encodes a transmembrane protein of unknown function, and the napD gene product is a soluble protein which is assumed to play a role in the maturation of NapA. Western blots of the periplasmic fraction from wild-type cells grown anaerobically with nitrate revealed the presence of a protein band with a molecular size of about 90 kDa corresponding to NapA. A B. japonicum mutant carrying an insertion in the napA gene was unable to grow under nitrate-respiring conditions, lacked nitrate reductase activity, and did not show the 90 kDa protein band. Complementation of the mutant with a plasmid bearing the napEDABC genes restored both nitrate-dependent anaerobic growth of the cells and nitrate reductase activity. A membrane-bound and a periplasmic c-type cytochrome, with molecular masses of 25 kDa and 15 kDa, respectively, were not detected in the napA mutant strain incubated anaerobically with nitrate, which identifies those proteins as the NapC and the NapB components of the B. japonicum periplasmic nitrate reductase enzyme. These results suggest that the periplasmic nitrate reductase is the enzyme responsible for anaerobic growth of B. japonicum under nitrate-respiring conditions. The promoter region of the napEDABC genes has been characterized by primer extension. A major transcript initiates 66.5 bp downstream of the centre of a putative FNR-like binding site.

Control biológico del "cogollero del maíz" Spodoptera frugiperda, (Lepidoptera; Noctuidae) con el baculovirus sfvpn, en Iquitos-Perú / Biological control of \"cogollero corn\" Spodoptera frugiperda (Lepidoptera; Noctuidae) with the baculovirus sfvpn in Iquitos-Peru

Con el propósito de encontrar una alternativa al control químico del "cogollero del maíz" Spodoptera frugiperda, principal plaga para el cultivo del maíz (Zea mays), se estudió la posibilidad de utilizar como controlador biológico de esta plaga, al baculovirus SfVPN (Virus de Poliedrosis Nuclear de Spodoptera frugiperda). Utilizando larvas del 3er estadío se comprobó que es un eficiente controlador biológico, determinándose que la dosis letal media fue de 49,653 cuerpos de inclusión (CI)/larva, con un promedio de tiempo letal medio (TL50) de 6.5 más menos 0.5 días. Asímismo, el número de CI del SfVPN producidos por una larva de 5to estadío fue de 5.4X10 CI/larva, y de 6to estadío fue de 7.3X10 CI/larva, constituyéndose estos estadíos en buenas productoras de virus para formulaciones de insecticidas biológicos. Se propone, por tanto, el empleo del SfVPN como una alternativa para el control de Spodoptera frugiperda.

Carriage of the classical thermotolerant campylobacters in health domestic animals from Earstern Peru

Com o objetivo de conhecer a importancia dos animais domesticos como reservatorios naturais dos classicos campylobacters termotolerantes, amostras de fezes foram obtidas de mamiferos e aves do leste do Peru e imediatamente colocadas num meio de enriquecimento. Tecnicas convencionais foram utilizadas para identificar C. jejuni ssp. jejuni, C. coli e C. lari. Campylobacter foi isolado em 26,5 por cento dos animais estudados, sendo C. jejuni ssp. jejuni biovar I o mais frequente (8,9 por cento). O frango foi o reservatorio mais importante destes microorganismos (54,0 por cento).

Aislamiento de especies termotolerantes de Campylobacter en dos poblaciones de pollos criados con y sin confinamiento / Isolation of thermotolerant Campylobacter species from two populations of chickens bred in confinement and at liberty

Estuda a freqüência de isolamento de Campylobacter spp. em frangos domésticos e frangos mantidos em confinamento permanente, na cidade de Iquitos (Peru). Campylobacter spp. foi isolado em 54,0 por cento no primeiro grupo e 35,0 por cento no segundo (p<0,005). Das espécies termotolerantes clássicas, as mais freqüentes foram C. jejuni e C. coli. A presença de C. Iari nessas aves, assinala a importância delas como reservatório natural desse microrganismo

Chicken as potential contamination source of Campylobacter lari in Iquitos, Peru

Com objetivo de conhecer a importancia dos frangos como reservatorio natural de Campylobacter lari na cidade de Iquitos, Peru, foram estudadas amostras cloacais obtidas de 200 aves. Cada amostra foi semeada em meio de enriquecimento semi-solido e no agar de Skirrow modificado. C. lari foi isola do em 21(10,5 por cento) amostras. Destes, 58,8 (por cento) corresponderam ao biotipo I e 41,2 (por cento) ao biotipo II do esquema de Lior. Os resultados obtidos sugerem que os frangos podem ser um importante reservatorio de C. lari em Iquitos, Peru.