Biologie Appliquée
http://depot.umc.edu.dz/handle/123456789/4870
2024-03-19T02:03:32ZRecherche et isolement de bactéries du genre Bacillus de différents écosystèmes particuliers algériens
http://depot.umc.edu.dz/handle/123456789/14219
Recherche et isolement de bactéries du genre Bacillus de différents écosystèmes particuliers algériens
Rehamnia, Baraa; Kacem Chaouche, Noreddine; Lee, Natuschka
With the discovery of numerous caves on planet Mars and the exploration of different types of caves on Earth, the interest and use of cave microorganisms has increased significantly during the last years. Hence, the purpose of this study is to present the first novel data on the presence of culturable, spore-forming bacteria in 10 different caves in Algeria, at depths down to 450 m. Two hundred fifty spore-forming isolates were obtained and their probiotic potential was tested with different methods (pathogenicity, growth at 37°C, survival in gastric juice and simulated intestinal fluid, antibiotic sensitivity, presence of digestive enzymes such as -galactosidase and gliadinase and cell surface properties). 13 of these tested strains (affiliated either to Bacillus or Paenibacillus, according to 16S rRNA analyses by FISH and gene sequencing) showed a rich spectrum of enzymatic and probiotic potential. These strains and their enzymes may therefore serve as useful candidates for future research in food processing and in reducing the effect of
digestive disorders. These findings also suggest that novel strains with biotechnological potential
can be discovered in pristine, subsurface ecosystems. Phylogenetic evaluation revealed that all selected isolates are affiliated to different Bacilli taxa within Firmicutes: B.gobiensis, B.subtilis, B.tequilensis, B.zhangzhouensis, B.pumilus, B.megaterium, B.simplex and B.pabuli.
2022-12-17T00:00:00ZInteraction Triticum durum/aestivum, Fusarium spp. et Trichoderma spp.
http://depot.umc.edu.dz/handle/123456789/13220
Interaction Triticum durum/aestivum, Fusarium spp. et Trichoderma spp.
Bouanaka, Hamza; Bellil, Ines
Wheat (Triticum spp.) is one of the most important cereals in the world. Unfortunately,
the wheat plant is the target of several species of the genus Fusarium. This genus causes two
serious diseases: crown rot (FCR) and head blight (FHB). In this work a survey was
conducted to study the most important species associated with this disease in Algeria, then
two research axes were approached to try to solve this problem.
One hundred and seventeen samples were collected (2019), sixty-three from the crown
and fifty-four from wheat grains in several regions of northeast Algeria. Fusarium spp. were
identified to the species level by sequencing the internal transcribed spacer (ITS1) regions of
the rDNA. Also their life traits (growth rate and sporulation rate) were measured.
Pathogenicity tests of the isolates were performed by two methods in vitro (tube test) and in
vivo (pot test).A highly pathogenic strain of Fusarium culmorum (FC11) was used in three
tolerance/susceptibility trials to evaluate the varietal resistance of eight cultivars (cv) of
durum wheat and nine of bread wheat widely marketed in Algeria, several phenotypic
parameters were measured. The biocontrol potential of 15 Trichoderma isolates (T1 to T15),
isolated from different rhizosphere soils and Algerian ecosystems, was evaluated against 4
strains of F. culmorum (FC11, FC2, FC4, and FC20), in order to identify a new indigenous
strain with a high biocontrol potential against FCR and FHB. This potential was evaluated by
in vitro tests (direct and indirect confrontation) and confirmed by in vivo tests. In addition,
tests in the greenhouse and in the field were carried out in order to select a better bio-control
treatment method by using these indigenous strains.
A total of 34 isolates representing 10 Fusarium species were obtained. The results
showed the existence of five Fusarium species isolated from the crowns; Fusarium culmorum
(16), F. cerealis (3), F. acuminatum (2), F. graminearum (1) and F. oxysporum (1); and seven
species isolated from grains; F. culmorum (3), F. incarnatum (3), F. graminearum (1), F.
equiseti (1), F. asiaticum (1), F. fujikuroi (1) and F. brachygibbosum (1). F. culmorum strains
were dominant and more aggressive, as well as F. graminearum and F. cerealis which were
aggressive in the in vitro test.However, the rest of the species were saprophytic rather than
aggressive. A significant correlation was recorded between growth rate and sporulation rate (r
=0.35 P=0.012<0.05). Also a strong correlation was recorded between the tube test and the
pot test (r =0.62, P=0.007<0.01), this result demonstrates the effectiveness of a simple in vitro
test to predict the aggressiveness of F. culmorum on wheat FCR. The cv. Sétifis and
Akhamokh showed the most interesting tolerance levels among the tested durum and bread wheat cultivars, respectively. In this study, we concluded that a simple, easy and stable in
vitro petri dish test can be used to predict the varietal resistance of different wheat cultivars
against initial seed infection by F. culmorum. The results of the in vitro Trichoderma
biocontrol showed significant inhibition of mycelial growth of F. culmorum species compared
to the control. Isolate T14 was selected for biocontrol in in vivo tests. Tube and pot
experiments against F. culmorum (FC2) showed that T14 decreased the severity of FCR with
50 and 63.63% reduction, respectively. FHB infection was significantly reduced by T14 in all
tested durum wheat cultivars. The antagonist T14 was molecularly characterized using
translation elongation factor 1-alpha (TEF1-α) and ITS1. Results identified T14 as
Trichoderma afroharzianum with accession numbers assigned by NCBI GenBank as
MW171248 and MW159753.
This study highlights that F. culmorum is the dominant species associated with FCR
and FHB in Algeria. Moreover, this is the first report concerning the identification of F.
incarnatum, F. fujikuroi, F. cerealis, F. asiaticum, F. oxysporum, F. acuminatum and F.
brachygibbosum of wheat in Algeria. Also this study highlighted the complexity of resistance
testing against FCR and FHB, and demonstrated the need to use as many resistance screening
protocols as possible. Trichoderma afroharzianum, evaluated for the first time in Algeria as a
biocontrol agent, is a promising biocontrol approach against Fusarium. In addition, the biocontrol treatment with coated seeds before sowing showed a higher efficacy among the tested
treatment methods.
2022-03-14T00:00:00ZEffet comparatif de l’extrait butanolique de la plante Stachys mialhesi avec les vitamines B9 et B12 sur quelques paramètres biochimiques et la structure de l’aorte chez des souris induites par une hyperhomocystéinémie
http://depot.umc.edu.dz/handle/123456789/4878
Effet comparatif de l’extrait butanolique de la plante Stachys mialhesi avec les vitamines B9 et B12 sur quelques paramètres biochimiques et la structure de l’aorte chez des souris induites par une hyperhomocystéinémie
Boudebouz Samira; Zerizer S
Homocysteine (Hcy) is a sulfur amino acid, synthesized from the metabolism of Lmethionine.
There is a balance in the metabolism of Hcy at physiological conditions.
At high level, the hyperhomocysteinemia (HHcy), considered as an independent risk factor in atherosclerosis, which can cause cellular and molecular alterations.
In the present study, we have measured thiol amino acid (homocysteine), lipidic statut (total cholesterol, LDL, HDL, triglycerides), and activity of transaminases (GOT, GPT) in mice administered with (400mg/kg) of L-methionine during 21 days. Following oral administration of L-methionine in high dose, its degradation product Hcy which is markedly
elevated in plasma and exerts an angiotoxic action directed to the iliac aorta and the other organs (liver, heart and kidneys). This is showed degradation and desquamation of endothelial cells also formation of foam cells in the media part with oval nuclei in mediocytes.
However, the aortic intima of the groups of mice that had been fed with L-methionine plus S.
mialhesi extract (500mg/kg) and also with vitamins B9 and B12 (0,7mg/kg and 0,75μg/kg), respectively showed intact endothelium and spindle-shaped mediocytes nuclei. Nevertheless, oval-shaped mediocytes nuclei and a few foam cells were observed. In the histological sections of the cardiac muscle, liver and kidneys no lysis was observed.
The vitamins B9 and B12 serve as cofactors in the metabolism of L-methionine. So, the vitamins therapy and the extract of S. mialhesi in mice have reduced Hcy, total cholesterol, triglycerides and LDL however, the concentration of HDL was increased.
The extract of medicinal plant S. mialhesi used in this study has antioxidant effect as the vitamins B9 and B12 in mice.
Our results obtained in this study showed that S. mialhesi can be considered as natural source in the prevention against cardiovascular disease.
104 f.
2017-01-01T00:00:00ZEtude comparative du contenu phénolique et du pouvoir antioxydant de quelques plantes médicinales et des céréales alimentaires.
http://depot.umc.edu.dz/handle/123456789/4877
Etude comparative du contenu phénolique et du pouvoir antioxydant de quelques plantes médicinales et des céréales alimentaires.
Khelfallah Amina; Merghem R
179 f.
2017-01-01T00:00:00Z