30 research outputs found
Antioxidant, antibacterial, and antileishmanial potential of Micromeria nervosa extracts and molecular mechanism of action of the bioactive compound
No full textAims: This study aimed to determine the antibacterial and antileishmanial potential of Micromeria nervosa extracts. The identification of the
antileishmanial compound and the study of its molecular mechanism of action have also been undertaken.
Methods and results: Ethanol extract showed high polyphenol content and diethyl ether extract exhibited high DPPH scavenging and low
beta-carotene bleaching activity (IC50 = 13.04 ± 0.99 and 200.18 ± 3.32 μg mL−1 , respectively). However, diethyl ether extract displayed high
antibacterial activity against Gram-positive strains including methicillin-resistant Staphylococcus aureus (MIC = 31.25 μg mL−1 ), Staph. aureus
ATCC6538 (MIC = 62.5 μg mL−1 ), and Listeria monocytogenes ATCC 19115 (MIC = 125 μg mL−1 ), as well as high antileishmanial activity against
the promastigote forms of L. infantum and L. major (IC50 = 11.45 and 14.53 μg mL−1 , respectively). The active compound was purified using
bioassay-guided fractionation and thin layer chromatography, and identified as ursolic acid using high-performance liquid chromatography coupled
with a photodiode array and mass spectrometry. The purified compound was strongly inhibitory against the promastigote and amastigote forms
of L. infantum and L. major (IC50 = 5.87 and 6.95 μg mL−1 versus 9.56 and 10. 68 μg mL−1 , respectively) without overt cytotoxicity against
Raw 264.7 macrophage cells (SI = 13.53 and 11.43, respectively). The commercial compound (ursolic acid) showed similar activity against
amastigotes and promastigotes forms of L. infantum and L. major. Moreover, its molecular mode of action against leishmaniasis seems to
involve the expression of the ODC and SPS genes involved in thiol pathway.
Conclusion: Extracts of M. nervosa can be considered as a potential alternative to antimicrobial and antileishmanial drugs
Towards the use of Cupressus sempervirens L. organic extracts as a source of antioxidant, antibacterial and antileishmanial biomolecules
No full textCupressus sempervirens L. is largely used in traditional medicine as an antimicrobial agent. The present study investigated the antioxidant, antibacterial and antileishmanial activities of C. sempervirens organic extracts at different phenological stages. Antioxidant activity was determined by DPPH (2,2-diphenyl-1-picrylhydrazylradical) scavenging assay, ferric reducing power and total antioxidant capacity. The antibacterial activity was evaluated against five clinical strains by disk diffusion method and minimum inhibitory concentration (MIC). The antileishmanial activity was determined against promastigote and amastigote forms of Leishmania (L.) infantum and L. major. Results of antioxidant activity showed that methanolic extract from vegetative stage had the most important activity. The ethyl acetate extract of C. sempervirens from flowering stage was the most active against Bacillus cereus (ATCC 14579) and Staphylococcus aureus (ATCC 25923) with MIC of 100 μg/mL and 50 μg/mL, respectively. Interestingly, this extract exhibited high antileishmanial activity against promastigote form of L. infantum and L. major (IC50 = 1.47 and 2.8 μg/mL, respectively) and amastigote form (IC50 = 3.61 and 5.42 μg/mL, respectively). Furthermore, ethyl acetate extract showed low cytotoxicity on macrophage cells Raw264.7 with selectivity index of 34.15 and 17.93 for L. infantum and L. major, respectively. The identification by HPLC and HPLC-MSn of active extracts of C. sempervirens revealed that major compounds of methanolic extract from vegetative stage and ethyl acetate extract from flowering stage were cupressuflavone and amentoflavone. Based on these results, C. sempervirens extracts could be used as an alternative to chemical drugs for the treatment of oxidative stress and infectious diseases
Audiovisual Analysis of Music Performances: Overview of an Emerging Field
No full textIn the physical sciences and engineering domains, music has traditionally been considered an acoustic phenomenon. From a perceptual viewpoint, music is naturally associated with hearing, i.e., the audio modality. Moreover, for a long time, the majority of music recordings were distributed through audio-only media, such as vinyl records, cassettes, compact discs, and mp3 files. As a consequence, existing automated music analysis approaches predominantly focus on audio signals that represent information from the acoustic rendering of music.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Multimedia Computin
Synergistic Antileishmanial Activity of Erythrodiol, Uvaol, and Oleanolic Acid Isolated from Olive Leaves of cv. Chemlali
No full textThis is an accepted version of the following published document: Lafi O, Essid R, Lachaud L, et al (2023) Synergistic antileishmanial activity of erythrodiol, uvaol, and oleanolic acid isolated from olive leaves of cv. Chemlali. 3 Biotech 13:395. https://doi.org/10.1007/s13205-023-03825-3.
This version of the article has been accepted for publication, after peer review (when applicable) and is subject to Springer Nature’s AM terms of use, but is not the Version of Record and does not reflect post-acceptance improvements, or any corrections. The Version of Record is available online at: https://doi.org/10.1007/s13205-023-03825-3.[Abstract] This study aimed to assess the antileishmanial activity of biomolecules obtained from Olea europaea L. leaves and twigs recovered from eight Tunisian cultivars. The extraction was first carried out with 80% methanol, and then the obtained extract was fractionated using three solvents of increasing polarity: cyclohexane (CHX), dichloromethane (DCM) and ethyl acetate (EtOAc). The antileishmanial activity was determined against leishmanial strains responsible for cutaneous, visceral, and mucocutaneous leishmaniasis. The cyclohexane fraction of the leaves of cv. Chemlali from the region of Sidi-Bouzid exhibited the strongest leishmanicidal activity against all the tested leishmanial strains. The inhibition concentrations (IC50) were 16.5, 14.5, and 7.4 μg mL−1 for Leishmania mexicana (cutaneous), Leishmania braziliensis (mucocutaneous), and Leishmania donovani (visceral), respectively. Interestingly, low cytotoxicity was observed on THP-1 cells with selective indexes (SI) ranging from 22.8 to 50.5. HPLC-HRMS and full-house NMR analysis allowed the identification of three triterpenic compounds, oleanolic acid (IC50 = 64.1 μg mL−1), erythrodiol (IC50 = 52.0 µg mL−1), and uvaol (IC50 = 53.8 μg mL−1). Antileishmanial activity of uvaol and oleanolic acid has been previously reported. However, this work constitutes the first report of the antileishmanial activity of erythrodiol which showed combinatorial interaction with uvaol (IC50 = 26.1 μg mL−1) against Leishmania tropica. The mixture of the three compounds, as major ones, exhibited an enhanced activity against Leishmania tropica (IC50 = 16.3 µg mL−1) compared to erythrodiol alone or the combination of uvaol and erythrodiol. This finding is of great importance and needs further investigation.The research leading to this paper was funded by the Tunisian Ministry of Higher Educatio
Seroprevalence of Toxoplasma gondii infection among horses in Tunisia
No full textAbstract
Background
The present study was conducted to investigate the serological survey of Toxoplasma antibodies in local.horses from three major regions: a neighbourhood of a city in the North (Sidi Thabet), a neighbourhood of a city on the coast (Monastir) and a neighbourhood of a city in the middle (Battan) of Tunisia (North of Africa).
Methods
A total of 158 serum samples were obtained from clinically healthy horses which consisted of 111 (32 female, 79 male) 2-10 years old and 47 (11 female, 36 male) older than 10 years. All of the horses were tested for antibodies to T. gondii using the Modified Agglutination Test (MAT).
Results
According to MAT results, antibodies to T. gondii were found in 28 (17.7%) of 158 sera with the titers of 1:20 in 20 horses, 1:40 in 1 horse, 1:80 in 2 horses, 1:160 in 2 horses, 1:320 in 1 horse and ≥1:640 in 2 horses. Anti-T. gondii antibodies were found in 18 (16.2%) of 111 horses (2-10 years old) and 10 (21.2%) of 47 horses (older than 10 years old). Six (13.9%) out of 43 female had anti-toxoplasma antibodies and 22 (19.1%) from 115 males remained positive.
Conclusion
Statistically significant differences in age groups and genders were observed between the seropositive and seronegative horses using the Chi square X(2) test. Other statistical correlation was also reported concerning horse breed.
</jats:sec
Genetic diversity of Cryptosporidium isolates from human populations in an urban area of Northern Tunisia.
No full textInternational audienceCryptosporidium is an enteric parasite infecting a wide range of hosts. It has emerged as an important cause of chronic life-threatening diarrhea in humans worldwide. Several subtypes of Cryptosporidium sp. have been described to be responsible for several large outbreaks related to water contamination in developed countries. However, there is a lack of information in the genetic diversity of Cryptosporidium among human population especially in developing countries. The present study aimed to update and report the genetic diversity of human Cryptosporidium spp. at the subtype level in an urban area of Tunisia using the 18S rRNA and gp60 gene. Genotyping of 42 Cryptosporidium positive isolates from different human populations at the 18S rRNA locus has identified three Cryptosporidium species: C. hominis (n = 20), C. parvum (n = 19), C. meleagridis (n = 2) and a co-infection C. hominis/C. meleagridis (n = 1). The sub-genotyping of these isolates at the 60-kda glycoprotein (gp60) locus was possible in 40 cases. It showed the presence of three subtype families (IIa, IIb and IIc) within C. parvum, a single subtype family within C. hominis and C. meleagridis isolates (Ia and IIIb respectively). Several subtypes were implicated in different human populations with the dominance of IaA26G1R1, IIaA15G2R1, IIdA16G1R1, IIdA22G2R1 and IIIbA26G1R1 variant respectively for C. hominis, C. parvum and C. meleagridis. The distribution of Cryptosporidium isolates in urban area of Northern Tunisia was dominated by the anthroponotic transmission via C. hominis species and the IIc subtype of C. parvum. However, zoonotic transmission is still possible in this region via zoonotic subtypes of C. parvum (IIa and IId) and C. meleagridis (IIIb). Subtype diversity was higher in this area
Glycoprotein 60 diversity in Cryptosporidium parvum causing human and cattle cryptosporidiosis in the rural region of Northern Tunisia.
No full textInternational audienceThe zoonotic potential of Cryptosporidium parvum was studied in an extensive cattle farming region of northern Tunisia. Seventy fecal samples from pre-weaning calves and 403 fecal samples from children were examined by microscopy after modified Ziehl-Neelsen (MZN) staining. Positive Cryptosporidium specimens were identified at a species level using an 18S rRNA nested polymerase chain reaction (PCR) followed by an Restriction Fragment Length Polymorphism (RFLP) analysis. C. parvum isolates were subgenotyped by sequence analysis of the glycoprotein 60 (gp60) gene. Among calf samples, 14 samples were positive by MZN method. C. parvum was identified in all cases. Twelve parvum isolates (85.7%) belonged to family subtype IIa. Subtype IIaA15G2R1 was more prevalent (50%). Two C. parvum isolates corresponded to the IIdA16G1 subtype. Seven human samples were positive by MZN method. C. parvum and C. meleagridis were identified in four and three cases, respectively. Intraspecific characterization of C. parvum identified two subtypes, the IIaA15G2R1 and the IIdA16G1, also found in calves
[Introduction to] Writing Centers at the Center of Change
No full textWriting Centers at the Center of Change looks at how eleven centers, internationally, adapted to change at their institutions, during a decade when their very success has become a valued commodity in a larger struggle for resources on many campuses.
Bringing together both US and international perspectives, this volume offers solutions for adapting to change in the world of writing centers, ranging from the logistical to the pedagogical, and even to the existential. Each author discusses the origins, appropriate responses, and partners to seek when change comes from within a school or outside it. Chapters document new programs being formed under changing circumstances, and suggest ways to navigate professional or pedagogical changes that may undermine the hard work of more than four decades of writing-center professionals.
The book’s audience includes writing center and learning-commons administrators, university librarians, deans, department chairs affiliated with writing centers. It will also be useful for graduate students in composition, rhetoric, and academic writing.https://scholarship.richmond.edu/bookshelf/1353/thumbnail.jp
Polymorphism study of Cryptosporidium hominis gp60 subtypes circulating in Tunisia.
No full textInternational audienceCryptosporidium spp. are a major cause of gastrointestinal diseases in humans worldwide. While a single subtype of Cryptosporidium hominis has been shown to be responsible for several large outbreaks related to water contamination in developed countries, little is known about the epidemiology of C. hominis in developing countries. This study reports the first genetic characterization of C. hominis at the subtype level in several human populations in Tunisia using the gp60 gene. Eighteen isolates were identified as C. hominis by a restriction fragment length polymorphism (RFLP) analysis. The prevalence of this species in different human populations ranges from 1.53% to 13.04% with a high prevalence being reported in immunocompromised children (13.04%) followed by patients with malignent myeloma (5.5%) and HIV-infected patients (4.59%). The gp60 analysis on C. hominis isolates, performed in 14 cases, showed the presence of a single subtype family: "Ia". Different subtypes were identified within this family (A11G1R1, A12R3, A23G1R1, A26G1R1, A27G1R1, A28G1R1). The IaA26G1R1 subtype was the most dominant subtype described in this area (50%). Despite the high genetic diversity of Cryptosporidium spp, a low heterogeneity at the subtype level was observed within C. hominis circulating in Tunisia. This distribution is an indicator for intensive and stable anthroponotic cryptosporidiosis in this region. Besides, the presence of a unique genotype in 5 HIV-infected patients attending the same hospital ward suggests the possible occurrence of hospital-acquired infection and underlines the need to implement preventive measures to avoid nosocomial transmission
Compositional profile of food supplements for honeybees
No full textMestrado de dupla diplomação com a Université Libre de TunisHoneybees (Apis mellifera L.) are the main pollinating agents for numerous
plants and fruit trees and, hence, play a key role in agriculture and more generally in
the maintenance of ecological biodiversity.
Like the most of organisms, honeybees need a diverse diet consisting of
minerals, carbohydrates (sugars), fats, and amino acids (proteins) to survive and
reproduce. An adult honey bees carbohydrate requirement is satisfied by the nectar
produced in flowers and also occasionally from extra floral nectarines or honeydew
secreted by plant-feeding insects, while, flower pollen is the main source of amino
acids, protein building blocks, largely used to feed developing larvae and young
bees to provide structural elements of muscles, glands and other tissues.
Bee-population declines are linked to nutritional shortages caused by land-use
intensification, which reduces diversity and abundance of plant species. Together
with the deficiency caused by adverse climatic changes and with the need to reduce
colony mortality and particularly to ensure good nutritional/health status of bees in
specific production moments, artificial supplementation of honeybee colonies
became a major issue in beekeeping, and now is a common and growing practice
within Portuguese beekeepers. This practice, in association with the reduced
regulation in this area is leading to the proliferation of commercial products based
on carbohydrates, protein and other substances of diverse origins and compositions.
The impact of these products on hives may enable the beekeeper to remedy colony
imbalances resulting from adverse or beekeeping conditions, but also may pose
risks to the bee’s health and the bee products quality, depending on the used raw
materials and the presence of harmful substances.
The present work, inserted within the project ApisCibus - Artificial food for
honeybees: quality survey, digestibility and performance on the bee hive, will have as
main objective to evaluate the quality of commercial honeybee artificial
supplementation through composition analysis of commercial supplements. The quality parameters evaluated are: minerals quantified through atomic absorption
spectroscopy, fatty acids analyzed by gas chromatography coupled to mass
spectrometry (GC-MS) and amino acids which are analyzed by ultra-performance
liquid chromatography coupled with electro spray ionization mass spectrometry
(UPLC-ESI-MS). Food supplements that are analyzed are largely used by
beekeepers without knowing if they are benefic or not, toxic or not on the health of
bees.
Furthermore the results of the analysis shows that what is represented on the
labels of products could be not exactly the same amounts of the real product inside
the package. It shows also that some products may be considered as benefic or as
toxic depending on the amount of these micronutrients.
To continue this work in order to confirm these hypothesis, in vitro tests could
be done on honeybees using these products analyzed in this thesis.
Through the obtained results we could observe that the high amount of free
amino acids presented in the studied supplements does not necessarily reflect a
good source of nutrients, considering that for the bee it is important to have access
to a diverse set of amino acids. Bee's nutritional requirements require 10 essential
amino acids (Arg, Phe, His, Ile, Leu, Lys, Met, Thr, Trp and Val). The supplement
P12 appears as the richest and most balanced, followed by P05. The C08
supplement, although containing an adequate proportion in most amino acids, has
an excessive amount of Arg, which may cause adverse effects.
Regarding fatty acids, the samples presented several compounds, among
which the most abundant were hexanoic acids, 9-octadecenoic acid (oleic acid) and
9,12-octadecadenoic acid (linoleic acid).
Although the role of fatty acids in bee nutrition is not yet fully understood,
compounds such as linoleic acid, linolenic acid, myristic acid and dodecanoic acid
appear to play an important role in inhibiting some microorganisms that affect bees,
as Paenibacillus larvae larvae (American foulbrood). For this reason the sample P05 appears as the one with the highest nutritional quality, since it presented a higher
number of fatty acids. In the analysis of minerals, it was observed that protein foods
are significantly richer in micronutrients. In this work, the most common elements
were potassium, sodium, calcium and magnesium, while copper and manganese
appeared in some foods in small quantities. Cadmium, often an associated element
with heavy metal contamination appeared in only one of the products, P05, but in
very small quantities, lead was not detected in any of the supplements.
In general, there were discrepancies between the results obtained and the
description available on product labels, making clear the need for further quality
control of these commercial products.As abelhas melíferas (Apis mellifera L.) são os principais agentes
polinizadores de inúmeras plantas e árvores frutíferas e, portanto, desempenham um
papel fundamental na agricultura e, de maneira mais geral, na manutenção da
biodiversidade ecológica. Como a maioria dos organismos, as abelhas precisam de
uma dieta diversificada, composta de minerais, hidratos de carbono, lípidos e
aminoácidos (proteínas) para sobreviver e se reproduzir. A necessidade de hidratos
de carbono de uma abelha adulta é satisfeita pelo néctar produzido pelas flores e
também, ocasionalmente, por meladas segregadas por insetos, enquanto o pólen de
flores é a principal fonte de aminoácidos, principais constituintes das proteínas,
tendo um papel preponderante no desenvolvimento de larvas e abelhas jovens,
fornecendo elementos estruturais de músculos, glândulas e outros tecidos.
O declínio das populações de abelhas está ligado à escassez nutricional
causada pela agricultura intensiva, que reduz a diversidade e a abundância de
espécies de plantas.Juntamente com a deficiência causada por alterações climáticas
adversas e com a necessidade de reduzir a mortalidade de colónias, particularmente
para garantir um bom estado nutricional/saúde das abelhas, a suplementação
artificial de colónias de abelhas tornou-se uma questão importante na apicultura,
sendo uma prática comum e crescente entre os apicultores portugueses. Esta prática,
associada à escassa regulamentação existente para este tipo de produtos, está a
aumentar a oferta comercial destes produtos.O impacto destes produtos nas
colmeias pode permitir ao apicultor remediar desequilíbrios existentes nas colónias,
resultantes de condições adversas ou de apicultura, mas também pode representar
riscos à saúde da abelha e à qualidade dos produtos apícolas, dependendo das
matérias-primas usadas e da presença de substâncias nocivas.
O presente trabalho, inserido no projeto ApisCibus - Alimentos artificiais para
abelhas: levantamento de qualidade, digestibilidade e desempenho sobre a colmeia,
teve como objetivo principal avaliar a qualidade de suplementos artificiais de abelhas comerciais através da análise da sua composição química. Os parâmetros de
qualidade avaliados foram: minerais, quantificados por espectroscopia de absorção
atómica, ácidos gordos,
Analisados por cromatografia gasosa acoplada a espectrometria de massas
(GC-MS) e aminoácidos analisados por cromatografia líquida de ultra-pressão
acoplada à espectrometria de massas por ionização por eletrospray (UPLC- ESIMS).
Através dos resultados obtidos pudemos observar que a elevada quantidade de
aminoácidos livres apresentada nos suplementos estudados, não reflete
necessariamente uma boa fonte de nutrientes, considerando que para a abelha é
importante ter acesso a um conjunto de aminoácidos diversificados. As exigências
nutricionais da abelha requerem 10 aminoácidos essenciais (Arg, Phe, His, Ile, Leu,
Lys, Met, Thr, Trp e Val).O suplemento P12 surge como o mais rico e equilibrado,
seguindo-se o P05. O suplemento C08, apesar de conter uma proporção adequada
na maioria dos aminoácidos, apresenta uma quantidade excessiva de Arg, o que
poderá provocar efeitos adversos. Relativamente aos ácidos gordos, as amostras
apresentaram diversos compostos, entre os mais abundantes os ácidos hexanóico,
ácido 9-octadecenóico (ácido oleico) e ácido 9,12-octadecadienóico (ácido
linoleico). Embora o papel dos ácidos gordos na nutrição das abelhas ainda não seja
totalmente compreendido, compostos
como o ácido linoleico, ácido linolénico, ácido mirístico e ácido dodecanóico
parecem ter um papel importante na inibição de alguns microorganismos que
afectam as abelhas, como Paenibacillus larvae larvae (Loque Americana). Por esta
razão a amostra P05 surge como a de maior qualidade nutricional, já que apresentou
um maior número de ácidos gordos. Na análise dos minerais, observou-se que os
alimentos proteicos são significativamente mais ricos em micronutrientes. Neste
trabalho, os elementos mais comuns foram o potássio, sódio, cálcio e magnésio,
enquanto cobre e o manganês surgiram em alguns alimentos em pequenas
quantidades. O cádmio, um elemento associado frequentemente com a
contaminação por metais pesados surgiu apenas num dos alimentos, P05, mas em quantidades muito reduzidas, já o chumbo não foi
detetado em nenhuma dos suplementos.
No geral, verificaram-se discrepâncias entre os resultados obtidos e a
descrição disponível nos rótulos dos produtos, tornando-se evidente a necessidade
de um maior controlo de qualidade destes produtos comerciais.The author thanks to Programa Apícola Nacional (2017-2019) for the funding to the
Apiscibus and to Fundação para a Ciência e Tecnologia (FCT) and FEDER inside the
Program PT2020 for the finantial support to CIMO (UID/AGR/00690/2019)
