scholarly journals Isolation and selection of Bacillus strains with high potential probiotic that used in catfish farming (Pangasianodon hypophthalmus)

2020 ◽  
Vol 10 (1) ◽  
pp. 3-16
Author(s):  
Nguyen Van Minh ◽  
Nguyen Hoang Tuan Duy ◽  
Do Phuong Quynh ◽  
Tran Thi A Ni ◽  
Tran Kien Duc ◽  
...  

In this study, we isolated 28 strains of Bacillus spp. from water samples, catfish pond mud samples and earthworm manure (Perionyx excavates). By the cross-streak agar methods, 22 Bacillus strains showed the inhibition ability to Edwardsiella ictaluri, which caused Bacillary Necrosis Pangasius (BNP) in catfish (Pangasianodon hypophthalmus). Both Bacillus sp. Q16 and Q111 strains showed the highest inhibition to E. ictaluri by the double-layer agar methods. Finally, two Bacillus strains (Q16, Q111) were selected as a source of potential probiotic because of the ability of extracellular enzyme secretion (protease, amylase, cellulose) strong growth at 0,1-1% salt concentrations, survival within the pH range 6-8, resistance to low pH and low bile salts, inability to produce haemolysin enzyme, sensitivity to eight antibiotics in the three impacting groups (inhibition of wall synthesis, inhibition mechanism of protein synthesis, inhibition of nucleic acid synthesis). Two Bacillus strains (Q16, Q111) were identified that they belong to Bacillus subtilis by biochemical method and 16S rRNA gene sequencing method. This study indicated that two Bacillus strains (Q16, Q111) isolated from catfish pond can be applied as high potential probiotics that used to farm catfish.

Toxins ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 294
Author(s):  
Yan Zhu ◽  
Pascal Drouin ◽  
Dion Lepp ◽  
Xiu-Zhen Li ◽  
Honghui Zhu ◽  
...  

Zearalenone (ZEA) is a mycotoxin widely occurring in many agricultural commodities. In this study, a purified bacterial isolate, Bacillus sp. S62-W, obtained from one of 104 corn silage samples from various silos located in the United States, exhibited activity to transform the mycotoxin ZEA. A novel microbial transformation product, ZEA-14-phosphate, was detected, purified, and identified by HPLC, LC-MS, and NMR analyses. The isolate has been identified as belonging to the genus Bacillus according to phylogenetic analysis of the 16S rRNA gene and whole genome alignments. The isolate showed high efficacy in transforming ZEA to ZEA-14-phosphate (100% transformation within 24 h) and possessed advantages of acid tolerance (work at pH = 4.0), working under a broad range of temperatures (22–42 °C), and a capability of transforming ZEA at high concentrations (up to 200 µg/mL). In addition, 23 Bacillus strains of various species were tested for their ZEA phosphorylation activity. Thirteen of the Bacillus strains showed phosphorylation functionality at an efficacy of between 20.3% and 99.4% after 24 h incubation, suggesting the metabolism pathway is widely conserved in Bacillus spp. This study established a new transformation system for potential application of controlling ZEA although the metabolism and toxicity of ZEA-14-phosphate requires further investigation.


Agronomy ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1344
Author(s):  
Naima Lemjiber ◽  
Khalid Naamani ◽  
Annabelle Merieau ◽  
Abdelhi Dihazi ◽  
Nawal Zhar ◽  
...  

Bacterial burn is one of the major diseases affecting pear trees worldwide, with serious impacts on producers and economy. In Morocco, several pear trees (Pyrus communis) have shown leaf burns since 2015. To characterize the causal agent of this disease, we isolated fourteen bacterial strains from different parts of symptomatic pear trees (leaves, shoots, fruits and flowers) that were tested in planta for their pathogenicity on Louise bonne and Williams cultivars. The results showed necrotic lesions with a significant severity range from 47.63 to 57.77% on leaves of the Louise bonne cultivar inoculated with isolate B10, while the other bacterial isolates did not induce any disease symptom. 16S rRNA gene sequencing did not allow robust taxonomic discrimination of the incriminated isolate. Thus, we conducted whole-genome sequencing (WGS) and phylogenetic analyzes based on gyrA, gyrB and cdaA gene sequences, indicating that this isolate belongs to the Bacillus altitudinis species. This taxonomic classification was further confirmed by the Average Nucleotide Identity (ANI) and the in silico DNA-DNA hybridization (isDDH) analyzes compared to sixty-five Bacillus spp. type strains. The genome was mined for genes encoding carbohydrate-active enzymes (CAZymes) known to play a role in the vegetal tissue degradation. 177 candidates with functions that may support the in planta phytopathogenicity results were identified. To the best of our knowledge, this is the first data reporting B. altitudinis as agent of leaf burn in P. communis in Morocco. Our dataset will improve our knowledge on spread and pathogenicity of B. altitudinis genotypes that appears as emergent phytopathogenic agent, unveiling virulence factors and their genomic location (i.e., within genomic islands or the accessory genome) to induce trees disease.


2019 ◽  
Vol 65 (10) ◽  
pp. 762-774 ◽  
Author(s):  
Alejandro Penaloza-Vazquez ◽  
Li Maria Ma ◽  
Patricia Rayas-Duarte

Probiotics have become one of the potential solutions to global restriction on antibiotic use in food animal production. Bacillus species have been attractive probiotics partially due to their long-term stability during storage. In this study, 200 endospore-forming bacteria isolates were recovered from sourdough and the gastrointestinal tract (GIT) of young broiler chicks. Based on the production of a series of exoenzymes and survivability under stress conditions similar to those in the poultry GIT, 42 isolates were selected and identified by 16S rRNA gene sequencing. Seven strains with a profile of high enzymatic activities were further evaluated for sporulation efficiency, biofilm formation, compatibility among themselves (Bacillus spp.), and antagonistic effects against three bacteria pathogenic to poultry and humans: Enterococcus cecorum, Salmonella enterica, and Shiga-toxin-producing Escherichia coli. The strains from sourdough were identified as Bacillus amyloliquefaciens whereas the ones from the chicks’ GIT were Bacillus subtilis. These strains demonstrated remarkable potential as probiotics for poultry.


Plants ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 941
Author(s):  
Nawal Benttoumi ◽  
Mariantonietta Colagiero ◽  
Samira Sellami ◽  
Houda Boureghda ◽  
Abdelaziz Keddad ◽  
...  

Fungi and bacteria associated to phytoparasitic nematodes Globodera rostochiensis and Meloidogyne spp. in Algeria were identified and characterized. Trichoderma spp. showed the highest prevalence in the cysts of G. rostochiensis. A number of isolates were identified through PCR amplification and the sequencing of the internal transcribed spacer (ITS)1-2 and Rpb2 gene regions. The most represented species were T. harzianum and T. afroharzianum. The latter and T. hirsutum were reported for the first time in Algeria. Fusarium spp., including F. oxysporum and F. solani, comprised a second group of fungi found in cysts. Taxa associated to females of Meloidogyne spp. included T. harzianum, Fusarium spp. and other hyphomycetes. To assess the efficacy of Trichoderma spp., two assays were carried out in vitro with the culture filtrates of two T. afroharzianum and T. harzianum isolates, to check their toxicity versus the second stage juveniles of M. incognita. After 24–48 h exposure, a mortality significantly higher than the control was observed for both filtrates at 1% dilutions. The TRI genes involved in the production of trichothecenes were also amplified with the PCR from some Trichoderma spp. isolates and sequenced, supporting a putative role in nematode toxicity. Bacteria isolated from the cysts of G. rostochiensis included Brucella, Rhizobium, Stenotrophomonas and Bacillus spp., identified through 16S rRNA gene sequencing. The potential of the microbial isolates identified and their mechanisms of action are discussed, as part of a sustainable nematode management strategy.


2020 ◽  
Vol 29 (1) ◽  
pp. 61-73
Author(s):  
Mst Aziza Begum ◽  
Nusrat Jahan Punom ◽  
Md Mostavi Enan Eshik ◽  
Mst Khadiza Begum ◽  
Tahsin Khan ◽  
...  

To identify the gut bacteria of Pangasianodon hypophthalmus (striped catfish; Pangas) using classical and molecular approach was carried out. Total bacterial count (TBC) in the gut of pangas from farm and market samples were found 5.07 ± 1.70 × 106 and 1.40 ± 0.47 × 106 cfu/g, respectively. The gut microbiota of pangas was dominated by members of the Gram-negative genera. Only three isolates (MyF1/1, MyF1/4 and GaW1/2) were found to be Gram-positive among the 16 representative isolates. Using 16S rRNA gene sequencing; Bacillus, Macrococcus, Citrobacter, Aeromonas, Proteus, Klebsiella, Enterobacter, Escherichia and Edwardsiella were found to be associated with the gut of this fish. Among them, Aeromonas was the most dominant genus (5 out of 16). Antibiotic sensitivity pattern reflected that all the isolates were sensitive to gentamycin. Multiple antibiotics resistant isolates were also identified of which MyF3/13 (identified as Citrobacter amalonaticus) was found resistant against seven tested antibiotics. The presence of pathogenic bacteria in fish gut revealed the improper handling practices in fish market and unhygienic condition in the culture sites which might be a reason of fish-borne disease outbreaks. On the other hand, widespread use of various antibiotics in aquaculture without proper awareness may lead to resistance to multiple antibiotics. Dhaka Univ. J. Biol. Sci. 29(1): 61-73, 2020 (January)


2020 ◽  
Vol 19 ◽  
pp. 18
Author(s):  
ELIANE APARECIDA GOMES ◽  
UBIRACI GOMES DE PAULA LANA ◽  
MARINA ELEUTÉRIO GÓI DE MORAES RODRIGUES ◽  
SYLVIA MORAIS DE SOUSA ◽  
CHRISTIANE ABREU DE OLIVEIRA ◽  
...  

The use of bioinoculants with plant growth-promoting bacteria (PGPB) is a sustainable agricultural practice that has been expanding worldwide. Thus, it is fundamental to characterize these bacteria molecularly to provide better security and traceability for bioinoculants production. This work aimed to identify, characterize and develop specific molecular markers for Bacillus strains related to plant-growing promotion. Five strains were identified as B. pumillus (B32), B. thuringiensis (B116), B. megaterium (B119) and B. subitilis (B2082 and B2084) using 16S rRNA gene sequencing and MALDI-TOF mass spectrometry. Repetitive element palindromic (Rep-PCR) and amplified ribosomal DNA restriction analysis (ARDRA) techniques allowed the discrimination of the strains, except B2082 and B2084 that presented identical genetic profiles, indicating that they are same or genetically close isolates. Moreover, specific molecular markers were developed for B116 and B119 strains and may be used for microbial inoculants production quality control, strains traceability and to detail PGPB colonization.


2019 ◽  
Vol 6 ◽  
pp. 1-9
Author(s):  
Pramod Poudel ◽  
Ashish Nepal ◽  
Rashmi Roka Magar ◽  
Pratibha Rauniyar ◽  
Lil Buda Magar

Objectives: To isolate arsenic resistant Bacillus spp. and to determine plant growth promoting activities.  Methods: Eighteen soil samples were collected from the agricultural soil of Terai region of Nepal. Selective isolation of Bacillus species was done by heating the soil at 80 ºC for 15 minutes before the isolation. Nutrient agar was used as an isolation medium. Screening of arsenic resistant Bacillus species was done using nutrient agar supplemented with 100 ppm sodium arsenate and sodium arsenite. For plant growth promoting activity; IAA production was detected taking 0.1% tryptophane and measuring absorbance at 540 nm, NH3 production was tested by Nessler’s reagent and phosphate solubilization activity was detected by growing colonies on Pikovskaya’s agar. Sugar assimilation test was performed to identify the isolates. Most potent arsenic resistant isolate was identified by 16S rRNA gene sequencing. Results: Among 54 randomly selected isolates, 42 were found to be Gram-positive rod-shaped, spore-forming while 12 isolates were Gram-negative bacteria. The isolates IN12a, M12a and BG34a showed growth on 100 ppm sodium arsenite containing NA. Only isolate M12a tolerated up to 1000 ppm and 15000 ppm of sodium arsenite and sodium arsenate respectively, while other isolates could not grow above 400 ppm sodium arsenite. The isolates IN12a and M12a were able to produce IAA and solubilize phosphate while BG34a could not. Both the isolates IN12a and M12a were able to utilize the sugars glucose, fructose, lactose, sucrose, galactose, mannose, mannitol, maltose and xylose.  Based on the 16S rRNA gene sequencing, isolate M12a was identified to be Bacillus flexus with highest similarity of 99.2%. Conclusion: Arsenic resistant and plant growth promoting Bacillus spp. was isolated from the agricultural soil of Terai region of Nepal


Cancers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2619
Author(s):  
Madhawa Gunathilake ◽  
Jeonghee Lee ◽  
Il Ju Choi ◽  
Young-Il Kim ◽  
Jaekyung Yoon ◽  
...  

Although the microbiome has a potential role in gastric cancer (GC), little is known about microbial dysbiosis and its functions. This study aimed to observe the associations between the alterations in gastric microbial communities and GC risk. The study participants included 268 GC patients and 288 controls. The 16S rRNA gene sequencing was performed to characterize the microbiome. Streptococcus_NCVM and Prevotella melaninogenica species were highly enriched in cases and controls, respectively. Those who were in the third tertile of P. melaninogenica showed a significantly decreased risk of GC in total (odds ratio (OR): 0.91, 95% confidence interval (CI): 0.38–0.96, p-trend = 0.071). Class Bacilli was phylogenetically enriched in cases, while phylum Actinobacteria, class Actinobacteria were related to the controls. The microbial dysbiosis index (MDI) was significantly higher for the cases compared with the healthy controls in the female population (p = 0.002). Females in the third tertile of the MDI showed a significantly increased risk of GC (OR: 2.66, 95% CI: 1.19-5.99, p-trend = 0.017). Secondary bile acid synthesis and biosynthesis of ansamycins pathways were highly abundant in cases and controls, respectively. Dysbiosis of gastric microbial communities is associated with an increased risk of GC specifically in females.


Author(s):  
Nkechi Gloria Ogbuji ◽  
Eromosele Anthony Ataga

Aims: Vegetables provide a favourable habitat for diverse populations of microorganisms. Some vegetables, especially the ones used in salads are ready-to-eat food products and some phyllosphere bacteria might contribute to the prolonged presence of human food-borne pathogens in these vegetables. Methodology: Phyllosphere bacteria associated with Cnidoscolus aconitifolius were evaluated using a culture-independent approach, Illumina MiSeq platform of 16S rRNA gene sequencing and then compared with publicly available data obtained from Spinacia oleracea (spinach) and Lactuca sativa (lettuce) on GenBank. Results: The results from this study showed that the three vegetables harbor diverse bacterial organisms. Eighty-three (83) Operational Taxonomic Units (OTUs) assigned to five phyla were obtained from C. aconitifolius phyllosphere. The most predominant phyla across studied vegetables were: Proteobacteria (74.79%), Actinobacteria (8.69%) and Firmicutes (7.37%). Potential human pathogenic species such as Bacillus spp., Enterococcus spp., Staphylococcus spp., Klebsiella spp., and Pseudomonas spp. were also present in lettuce and spinach. Bacteria with potential for antibiotic production, anti-microbial and antibiotic resistant genes belong to the families Bacillaceae, Streptomycetaceae, Pseudomonaceae, Enterobacteriaceae, Staphylococcaceae, Enterococcaceae and Streptococcaceae. The most abundant taxa obtained from this study were Pseudomonas, Erwinia, Brachybacterium, Megasphaera, Janthinobacterium, Sphingomonas and Lactobacillus. Conclusion: Our result successfully determined the relative abundance of potential human and plant pathogens in the leafy vegetables and also showed the bacterial community structure in the studied vegetables.


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