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1.
Microorganisms ; 12(5)2024 Apr 26.
Article En | MEDLINE | ID: mdl-38792693

Environmental pollution caused by petroleum-derived plastics continues to increase annually. Consequently, current research is interested in the search for eco-friendly bacterial polymers. The importance of Bacillus bacteria as producers of polyhydroxyalkanoates (PHAs) has been recognized because of their physiological and genetic qualities. In this study, twenty strains of Bacillus genus PHA producers were isolated. Production was initially evaluated qualitatively to screen the strains, and subsequently, the strain B12 or Bacillus sp. 12GS, with the highest production, was selected through liquid fermentation. Biochemical and molecular identification revealed it as a novel isolate of Bacillus cereus. Production optimization was carried out using the Taguchi methodology, determining the optimal parameters as 30 °C, pH 8, 150 rpm, and 4% inoculum, resulting in 87% and 1.91 g/L of polyhydroxybutyrate (PHB). Kinetic studies demonstrated a higher production within 48 h. The produced biopolymer was analyzed using Fourier-transform infrared spectroscopy (FTIR), confirming the production of short-chain-length (scl) polyhydroxyalkanoate, named PHB, and differential scanning calorimetry (DSC) analysis revealed thermal properties, making it a promising material for various applications. The novel B. cereus isolate exhibited a high %PHB, emphasizing the importance of bioprospecting, study, and characterization for strains with biotechnological potential.

2.
Int J Mol Sci ; 25(2)2024 Jan 13.
Article En | MEDLINE | ID: mdl-38256074

Systemic lupus erythematosus (SLE) is a multisystem disease considered a prototype of the main autoimmune disease and presents serious complications, such as lupus nephritis (LN), which generates a significant impact on morbidity and mortality. The SPP1 gene encodes the osteopontin (OPN) protein, which plays a crucial role in the regulation of inflammation and immunity. The variants rs1126616 and rs9138 of this gene have been associated with the inflammatory response. The study aims to analyze the association of the rs1126616 and rs9138 variants of the SPP1 gene in SLE Mexican-Mestizo patients without LN (SLE-LN). In this cross-sectional study, a total of 171 genomic DNA samples from SLE patients were clinically confirmed, of which 111 were SLE without LN, 60 were SLE with LN, and 100 healthy individuals were included as reference group. The rs1126616 variant was genotyped using PCR-RFLPs, and the rs9138 variant was genotyped using qPCR TaqMan. The TT genotype, the recessive model [OR 2.76 (95% CI 1.31-5.82), p = 0.011], and the T allele [OR 2.0 (95% CI 1.26-3.16), p = 0.003] of the rs1126616 variant are risk factors for SLE with LN. By contrast, the rs9138 variant did not show statistically significant differences among SLE patients stratified by LN. In our study of SLE Mexican-Mestizo patients with and without NL, demographic and clinical characteristics do not differ from other SLE populations, and the TT genotype of the rs1126616 variant of the SPP1 gene confers a risk factor for the presentation of LN. Otherwise, the rs9138 variant did not show association with NL.


Lupus Erythematosus, Systemic , Lupus Nephritis , Humans , Lupus Nephritis/genetics , Cross-Sectional Studies , Lupus Erythematosus, Systemic/genetics , Alleles , Genotype , Osteopontin
3.
Appl Microbiol Biotechnol ; 108(1): 94, 2024 Dec.
Article En | MEDLINE | ID: mdl-38212966

Di(2-ethylhexyl) phthalate (DEHP) is a plasticizer that is used worldwide and raises concerns because of its prevalence in the environment and potential toxicity. Herein, the capability of Fusarium culmorum to degrade a high concentration (3 g/L) of DEHP as the sole carbon and energy source in solid-state fermentation (SSF) was studied. Cultures grown on glucose were used as controls. The biodegradation of DEHP by F. culmorum reached 96.9% within 312 h. This fungus produced a 3-fold higher esterase activity in DEHP-supplemented cultures than in control cultures (1288.9 and 443.2 U/L, respectively). In DEHP-supplemented cultures, nine bands with esterase activity (24.6, 31.2, 34.2, 39.5, 42.8, 62.1, 74.5, 134.5, and 214.5 kDa) were observed by zymography, which were different from those in control cultures and from those previously reported for cultures grown in submerged fermentation. This is the first study to report the DEHP biodegradation pathway by a microorganism grown in SSF. The study findings uncovered a novel biodegradation strategy by which high concentrations of DEHP could be biodegraded using two alternative pathways simultaneously. F. culmorum has an outstanding capability to efficiently degrade DEHP by inducing esterase production, representing an ecologically promising alternative for the development of environmental biotechnologies, which might help mitigate the negative impacts of environmental contamination by this phthalate. KEY POINTS: • F. culmorum has potential to tolerate and remove di(2-ethylhexyl) phthalate (DEHP) • Solid-state fermentation is an efficient system for DEHP degradation by F. culmorum • High concentrations of DEHP induce high levels of esterase production by F. culmorum.


Diethylhexyl Phthalate , Fusarium , Phthalic Acids , Diethylhexyl Phthalate/metabolism , Biodegradation, Environmental , Esterases/metabolism
4.
World J Microbiol Biotechnol ; 39(11): 299, 2023 Sep 05.
Article En | MEDLINE | ID: mdl-37667093

The aim of this work was to find out if biofilms can be made by lactic acid bacteria (LAB) isolated from agave plants using agave fructans as sole carbohydrate substrates or if it was necessary to use fructose as a breakdown product of such polymers. This is part of a research project geared to develop industrial lactic acid production from agave fructans, an abundant raw material in Mexico's agave plantations. Present results showed that nine strains of LAB isolated from Agave salmiana and belonging to genus Lacticaseibacillus and Enterococcus produced exopolysaccharides directly from agave fructans to a greater extent than with fructose. The best polysaccharide productions in planktonic cultures were Lacticaseibacillus paracasei strains DG2, DG3, DG4 and DG8. Furthermore, all nine LAB strains produced biofilms on polystyrene microplates, much better with agave fructans than with fructose. In most strains, biofilm formation was favored at pH from 6.0 to 6.5, except for strains DG7 and DG9 where pH 5.5 was optimal. Biofilm formation required between 3 and 5 days of incubation in all Lacticaseibacillus paracasei strains, whereas Enterococcus faecium required a little less of 3 days. Present results support the straight use of agave fructans to develop LAB biofilms using agave epiphytic bacteria. This finding simplifies upstream processing of agave fructans to be used for future lactic acid fermentation in LAB biofilm reactors.


Agave , Lacticaseibacillus paracasei , Lactobacillales , Fructans , Biofilms , Fructose , Lactic Acid
5.
Article En | MEDLINE | ID: mdl-37573244

OBJECTIVE: To assess the trend in hepatitis A, hepatitis B, pneumococcal, tetanus and seasonal influenza vaccination in people with HIV infection and to analyse associated factors. METHODS: The Hospital Survey of Patients with HIV, an annual cross-sectional study conducted on a fixed day (2006-2021), was used. Inpatients and outpatients were included. Trends in vaccination and associated factors were analysed using logistic regression. RESULTS: A total of 8643 participants were included. Vaccination rates increased to 65.3% for hepatitis A, 83.7% for hepatitis B, 49.3% for tetanus, 68.9% for pneumococcal and 74.5% for seasonal influenza in 2021. Factors positively associated with vaccination were older age for pneumococcal and influenza vaccination; higher educational level for hepatitis A and tetanus; living in a closed institutions or prison for tetanus, pneumococcal and influenza; and having acquired HIV through sex between men for hepatitis A, B and pneumococcal. In addition, being on antiretroviral treatment and having a high CD4 count were positively associated with vaccination for all these diseases. Factors inversely associated with vaccination were being older (hepatitis A, B and tetanus), being an immigrant (tetanus and seasonal influenza) and being an injection drug user/ex-user for hepatitis A and B. CONCLUSIONS: Vaccination in people with HIV has increased in the study period. The results are in line with the recommendations in this population, although there is still room to reach the established vaccination indicators.

6.
Int Endod J ; 56(9): 1147-1154, 2023 Sep.
Article En | MEDLINE | ID: mdl-37334880

AIM: This study evaluated and compared the shaping ability of four rotary instrument systems in long-oval root canals using microcomputed tomographic (micro-CT) evaluation. Currently, there is no data available on the canal shaping abilities of BlueShaper and DC Taper instruments. METHODOLOGY: Sixty-four single-rooted mandibular premolars were matched based on similar root canal morphologic features as determined by (micro-CT) and randomly assigned to 1 of 4 experimental groups (n = 16) according to the instrument system used: BlueShaper, TruNatomy, DC Taper and HyFlex EDM One File. Changes in the root canal surface and volume, remaining dentine thickness, and number of prepared areas were assessed. RESULTS: No significant differences were found amongst the four instrument systems for the parameters evaluated (p > .05). There was a significant reduction in the number of unprepared areas and the remaining dentine thickness after each increase in size of the instruments tested (p < .05). CONCLUSIONS: The four instrument systems perform similarly in long oval root canals. Although none could prepare all canal walls, larger preparations incorporated significantly more surfaces in the final shape.


Dental Pulp Cavity , Root Canal Preparation , Dental Pulp Cavity/diagnostic imaging , Dental Pulp Cavity/anatomy & histology , Root Canal Therapy , X-Ray Microtomography/methods , Bicuspid/diagnostic imaging
7.
Andes Pediatr ; 94(2): 187-199, 2023 Apr.
Article Es | MEDLINE | ID: mdl-37358112

Sepsis is an important cause of pediatric morbidity and mortality, especially in low-income countries. Data on regional prevalence, mortality trends, and their relationship with socioeconomic variables are scarce. OBJECTIVE: to determine the regional prevalence, mortality, and sociodemographic situation of patients diagnosed with severe sepsis (SS) and septic shock (SSh) admitted to Pediatric Intensive Care Units (PICUs). PATIENTS AND METHOD: patients aged 1 to 216 months admitted to 47 participating PICUs with a diagnosis of SS or SSh between January 1, 2010, and December 31, 2018, were included. Secondary analysis was performed on the Argentine Society of Intensive Care Benchmarking Quality Program (SATI-Q) database for SS and SSh and a review of the annual reports of the Argentine Ministry of Health and the National Institute of Statistics and Census for the sociodemographic indices of the respective years. RESULTS: 45,480 admissions were recorded in 47 PICUs, 3,777 of them with a diagnosis of SS and SSh. The combined prevalence of SS and SSh decreased from 9.9% in 2010 to 6.6% in 2018. The combined mortality decreased from 34.5% to 23.5%. Multivariate analysis showed that the Odds ratio (OR) of the association between SS and SSh mortality was 1.88 (95% CI: 1.46-2.32) and 2.4 (95% CI: 2.16-2.66), respectively, adjusted for malignant disease, PIM2, and mechanical ventilation. The prevalence of SS and SSh in different health regions (HR) was associated with the percentage of poverty and infant mortality rate (p < 0.001). However, there was no association between sepsis mortality and HR adjusted for PIM2. CONCLUSIONS: Prevalence and mortality of SS and SSh have decreased over time in the participating PICUs. Lower socioeconomic conditions were associated with higher prevalence but similar sepsis outcomes.


Sepsis , Shock, Septic , Child , Humans , Infant , Hospitalization , Intensive Care Units, Pediatric , Poverty , Sepsis/epidemiology , Sepsis/therapy , Shock, Septic/epidemiology , Shock, Septic/therapy , Shock, Septic/complications , Child, Preschool , Adolescent
8.
Arch. cardiol. Méx ; 93(2): 223-232, Apr.-Jun. 2023. tab, graf
Article Es | LILACS-Express | LILACS | ID: biblio-1447254

Resumen Esta guía propone brindar una ayuda a todos los médicos para la identificación metódica de cada marca comercial de marcapasos por radiografía simple de tórax, por medio de sus componentes electrónicos (conectores de electrodos, circuito lógico y batería), siendo necesario para la interrogación de dispositivos de marcapasos posterior a su implante. Se describirán los diferentes tipos de marcapasos, electrodos y modos de programación más frecuentemente utilizados.


Abstract This guide provides help for medical doctors systematically identifying each commercial brand of pacemakers by thoracic radiography through their electronic components (electrode connectors, logic circuit, and battery); this is crucial for watching the pacemaker after being implanted. We aimed to describe the different cardiac stimulation devices, electrodes, and programming modes more frequently used.

9.
Front Pediatr ; 11: 1160335, 2023.
Article En | MEDLINE | ID: mdl-37215597

Cardiac electrical stimulation in children usually is needed in the setting of complete congenital atrioventricular block, atrioventricular block after heart surgery, and bradycardia associated with some specific channelopathies. In cases of atrioventricular block, the high percentage of ventricular stimulation raises concern on the deleterious effects of chronic stimulation of the right ventricle. In recent years, physiologic stimulation has developed as a valid approach for adult patients and a great interest has risen in offering conduction system pacing also to the pediatric population. We present three pediatric cases of stimulation of the conduction system (His bundle or left bundle branch), in order to show the intrinsic particularities and challenges implied in these new techniques.

10.
Arch Cardiol Mex ; 93(2): 223-232, 2023.
Article En | MEDLINE | ID: mdl-37037220

This guide provides help for medical doctors systematically identifying each commercial brand of pacemakers by thoracic radiography through their electronic components (electrode connectors, logic circuit, and battery); this is crucial for watching the pacemaker after being implanted. We aimed to describe the different cardiac stimulation devices, electrodes, and programming modes more frequently used.


Esta guía propone brindar una ayuda a todos los médicos para la identificación metódica de cada marca comercial de marcapasos por radiografía simple de tórax, por medio de sus componentes electrónicos (conectores de electrodos, circuito lógico y batería), siendo necesario para la interrogación de dispositivos de marcapasos posterior a su implante. Se describirán los diferentes tipos de marcapasos, electrodos y modos de programación más frecuentemente utilizados.


Arrhythmias, Cardiac , Pacemaker, Artificial , Humans , Cardiac Pacing, Artificial , Heart , Registries
11.
Article En | LILACS-Express | LILACS | ID: biblio-1440269

The incisive canal is innervated by the nasopalatine nerve and irrigated by the anterior branches of the descending palatine vessels, the sphenopalatine and greater palatine artery. Sometimes, the incisor canal interferes with the placement of implants or other surgical procedures, it is necessary to resort to previous treatments in order to have the ideal conditions in the area to be treated and avoid complications. Methods: 100 cone beam computed tomography were studied evaluating the diameter, length and shape of the incisor canal, distance from the lower edge of the incisor canal to the alveolar ridge, length and width of the bone anterior to the incisor canal, and width of the palatal bone. Results and conclusions: The variables that showed a statistically significant difference comparing between male and female patients were vestibulo-palatal and incisor foramen diameter, incisor canal length, distance from the canal to the central incisor, coronal and medial width of the vestibular bone; and the width of the palatal bone at apical and mid-level; being greater in male patients.

12.
J Electrocardiol ; 74: 146-153, 2022.
Article En | MEDLINE | ID: mdl-36240673

Short QT syndrome (SQTS) represents a diagnosis challenge where the symptoms may vary from palpitations in an otherwise asymptomatic patient to sudden death. Is a recently discovered rare channelopathy, identified by Gussak in 2000, characterized by short QT intervals on the electrocardiogram and a tendency to develop atrial and ventricular arrhythmias in the absence of structural heart disease, hyperkalemia, hypercalcemia, hyperthermia, acidosis and endocrine disorders. We present the case of a 16-year-old patient with short QT-type channelopathy, who presented with sinus arrest and junctional rhythm, who later developed atrial tachycardia and atrial flutter.


Electrocardiography , Sick Sinus Syndrome , Humans , Child , Adolescent , Sick Sinus Syndrome/complications , Sick Sinus Syndrome/diagnosis
13.
Sensors (Basel) ; 22(4)2022 Feb 14.
Article En | MEDLINE | ID: mdl-35214373

The Internet of Things (IoT) opens opportunities to monitor, optimize, and automate processes into the Agricultural Value Chains (AVC). However, challenges remain in terms of energy consumption. In this paper, we assessed the impact of environmental variables in AVC based on the most influential variables. We developed an adaptive sampling period method to save IoT device energy and to maintain the ideal sensing quality based on these variables, particularly for temperature and humidity monitoring. The evaluation on real scenarios (Coffee Crop) shows that the suggested adaptive algorithm can reduce the current consumption up to 11% compared with a traditional fixed-rate approach, while preserving the accuracy of the data.


Internet of Things , Agriculture , Algorithms , Humidity , Monitoring, Physiologic
14.
Comput Math Methods Med ; 2022: 5975228, 2022.
Article En | MEDLINE | ID: mdl-35222684

The mechanical heart valve is a crucial solution for many patients. However, it cannot function on the state of blood as human tissue valves. Thus, people with mechanical valves are put under anticoagulant therapy. A good measurement of the state of blood and how long it takes blood to form clots is the prothrombin time (PT); moreover, it is an indicator of how well the anticoagulant therapy is, and of whether the response of the patient to the drug is as needed. For a more specific standardized measurement of coagulation time, an international normalized ratio (INR) is established. Clinical testing of INR and PT is relatively easy. However, it requires the patient to visit the clinic for evaluation purposes. Many techniques are therefore being developed to provide PT and INR self-testing devices. Unfortunately, those solutions are either inaccurate, complex, or expensive. The present work approaches the design of an anticoagulation self-monitoring device that is easy to use, accurate, and relatively inexpensive. Hence, a two-channel polymethyl methacrylate-based microfluidic point-of-care (POC) smart device has been developed. The Arduino based lab-on-a-chip device applies optical properties to a small amount of blood. The achieved accuracy is 96.7%.


International Normalized Ratio/instrumentation , Lab-On-A-Chip Devices , Point-of-Care Testing , Prothrombin Time/instrumentation , Anticoagulants/therapeutic use , Computational Biology , Equipment Design , Heart Valve Prosthesis , Humans , International Normalized Ratio/methods , International Normalized Ratio/statistics & numerical data , Lab-On-A-Chip Devices/statistics & numerical data , Optical Devices/statistics & numerical data , Point-of-Care Testing/statistics & numerical data , Polymethyl Methacrylate , Prothrombin Time/methods , Prothrombin Time/statistics & numerical data , Self-Testing
15.
J Intensive Care Med ; 37(6): 753-763, 2022 Jun.
Article En | MEDLINE | ID: mdl-34812664

Objective: The aim of this study was to develop evidence-based recommendations for the diagnosis and treatment of sepsis in children in low- and middle-income countries (LMICs), more specifically in Latin America. Design: A panel was formed consisting of 27 experts with experience in the treatment of pediatric sepsis and two methodologists working in Latin American countries. The experts were organized into 10 nominal groups, each coordinated by a member. Methods: A formal consensus was formed based on the modified Delphi method, combining the opinions of nominal groups of experts with the interpretation of available scientific evidence, in a systematic process of consolidating a body of recommendations. The systematic search was performed by a specialized librarian and included specific algorithms for the Cochrane Specialized Register, PubMed, Lilacs, and Scopus, as well as for OpenGrey databases for grey literature. The GRADEpro GDT guide was used to classify each of the selected articles. Special emphasis was placed on search engines that included original research conducted in LMICs. Studies in English, Spanish, and Portuguese were covered. Through virtual meetings held between February 2020 and February 2021, the entire group of experts reviewed the recommendations and suggestions. Result: At the end of the 12 months of work, the consensus provided 62 recommendations for the diagnosis and treatment of pediatric sepsis in LMICs. Overall, 60 were strong recommendations, although 56 of these had a low level of evidence. Conclusions: These are the first consensus recommendations for the diagnosis and management of pediatric sepsis focused on LMICs, more specifically in Latin American countries. The consensus shows that, in these regions, where the burden of pediatric sepsis is greater than in high-income countries, there is little high-level evidence. Despite the limitations, this consensus is an important step forward for the diagnosis and treatment of pediatric sepsis in Latin America.


Sepsis , Child , Consensus , Critical Care/methods , Humans , Latin America , Sepsis/diagnosis , Sepsis/therapy
16.
In. Pedemonti, Adriana; González Brandi, Nancy. Manejo de las urgencias y emergencias pediátricas: incluye casos clínicos. Montevideo, Cuadrado, 2022. p.87-102, tab.
Monography Es | LILACS, UY-BNMED, BNUY | ID: biblio-1525429
17.
Sensors (Basel) ; 21(23)2021 Nov 25.
Article En | MEDLINE | ID: mdl-34883853

The collection of physiological data from people has been facilitated due to the mass use of cheap wearable devices. Although the accuracy is low compared to specialized healthcare devices, these can be widely applied in other contexts. This study proposes the architecture for a tourist experiences recommender system (TERS) based on the user's emotional states who wear these devices. The issue lies in detecting emotion from Heart Rate (HR) measurements obtained from these wearables. Unlike most state-of-the-art studies, which have elicited emotions in controlled experiments and with high-accuracy sensors, this research's challenge consisted of emotion recognition (ER) in the daily life context of users based on the gathering of HR data. Furthermore, an objective was to generate the tourist recommendation considering the emotional state of the device wearer. The method used comprises three main phases: The first was the collection of HR measurements and labeling emotions through mobile applications. The second was emotional detection using deep learning algorithms. The final phase was the design and validation of the TERS-ER. In this way, a dataset of HR measurements labeled with emotions was obtained as results. Among the different algorithms tested for ER, the hybrid model of Convolutional Neural Networks (CNN) and Long Short-Term Memory (LSTM) networks had promising results. Moreover, concerning TERS, Collaborative Filtering (CF) using CNN showed better performance.


Neural Networks, Computer , Wearable Electronic Devices , Algorithms , Emotions , Humans , Memory, Long-Term
18.
J Healthc Eng ; 2021: 8729108, 2021.
Article En | MEDLINE | ID: mdl-34925742

In the context of teaching-learning of motor skills in a virtual environment, videos are generally used. The person who wants to learn a certain movement watches a video and tries to perform the activity. In this sense, feedback is rarely thought of. This article proposes an algorithm in which two periodic movements are compared, the one carried out by an expert and the one carried out by the person who is learning, in order to determine how closely these two movements are performed and to provide feedback from them. The algorithm starts from the capture of data through a wearable device that yields data from an accelerometer; in this case, the data of the expert and the data of the person who is learning are captured in a dataset of salsa dance steps. Adjustments are made to the data in terms of Pearson iterations, synchronization, filtering, and normalization, and DTW, linear regression, and error analysis are used to make the corresponding comparison of the two datasets. With the above, it is possible to determine if the cycles of the two signals coincide and how closely the learner's movements resemble those of the expert.


Wearable Electronic Devices , Algorithms , Feedback , Humans , Learning , Movement
19.
Rev. med. vet. (Bogota) ; (43): 81-86, jul.-dic. 2021. graf
Article Es | LILACS-Express | LILACS | ID: biblio-1376996

Resumen La presencia del melanoma maligno cutáneo en felinos exóticos está pobremente reportada. Una hembra de tigre de Bengala blanca (Panthera tigris tigris), de 6 años, no castrada, solitaria y viviendo en un ambiente adecuado, fue evaluada por la presencia de una masa cerca del ojo izquierdo. La histopatología de la biopsia remitida mostró la presencia de melanocitos con características anaplásicas (pleomorfismo, citomegalia, cariomegalia, binucleación), área hemorrágica y foco inflamatorio fibrinoso. El diagnóstico histopatológico fue melanoma maligno. Dos meses después del diagnóstico, la tigresa manifestó un deterioro considerable con pérdida de peso y presencia de una masa redonda en el cuello. En aquel momento, por su tamaño, el melanoma obstruía totalmente la visión. Con base en esto, y por razones humanitarias, el animal fue eutanasiado. Al momento de la necropsia, se observó metástasis en pulmones, pleura y riñones. Este caso evidencia la importancia de dar a conocer la presentación de melanomas en especies poco reportadas.


Abstract The occurrence of cutaneous malignant melanoma in exotic felids is poorly reported. A 6-year-old, unneutered, solitary, female white Bengal tiger (Panthera tigris tigris), living in a suitable environment, was evaluated for the presence of a mass near the left eye. Histopathology of the referred biopsy showed the presence of melanocytes with anaplastic features (pleomorphism, cytomegaly, karyomegaly, binucleation), hemorrhagic area and fibrinous inflammatory focus. The histopathological diagnosis was malignant melanoma. Two months after diagnosis, the tigress manifested considerable deterioration with weight loss and the presence of a round mass on the neck. At that time, because of its size, the melanoma totally obstructed vision. Based on this, and for humane reasons, the animal was euthanized. At the time of necropsy, metastasis was observed in the lungs, pleura and kidneys. This case demonstrates the importance of raising awareness of melanomas in underreported species.

20.
World J Microbiol Biotechnol ; 37(9): 154, 2021 Aug 16.
Article En | MEDLINE | ID: mdl-34398297

Bacillus thuringiensis (Bt) (Bacillales:Bacillaceae) is a gram-positive bacterium that produces spores, several virulence factors and insecticidal toxins, making this microorganism the most used biopesticide worldwide. The use of inert supports such as polyurethane foam (PUF) in solid cultures has been a great alternative to produce various metabolites, including those produced by Bt. In this study we compared the yields, productivity and quality of the spores by two wild strains of Bt, (Y15 and EA3), grown in media with high substrate concentration in both culture systems: liquid and solid (PUF as solid inert support). Both strains showed 2.5- to 30-fold increases in spore production and productivity in solid culture, which showed an even greater increase when considering the spores retained in the PUF observed by scanning electron microscopy. Moreover, spore produced in solid culture showed up to sevenfold higher survival after a heat-shock treatment, relative to spores from liquid culture. The infectivity against larvae of Galleria mellonella (Lepidoptera:Pyralidae) improved also in spores from solid cultures. This comparison showed that the culture of Bt on solid support has clear advantages over liquid culture in terms of the production and quality of spores, and that those advantages can be attributed only to the culture system, as the same media composition was used in both systems.


Bacillus thuringiensis/physiology , Polyurethanes/chemistry , Spores, Bacterial/growth & development , Animals , Bacillus thuringiensis/pathogenicity , Bacteriological Techniques , Culture Media/chemistry , Larva/microbiology , Lepidoptera/microbiology , Microscopy, Electron, Scanning
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