Advanced Journal of Microbiology Research

Advanced Journal of Microbiology Research ISSN 2241-9837 Vol. 14 (4), pp. 001-007, April, 2020. © International Scholars Journals

Full Length Research Paper

A simple double-layered chrome azurol S agar (SD-CASA) plate assay to optimize the production of siderophores by a potential biocontrol agent Bacillus

Qing-Ping Hu¹ and Jian-Guo Xu²*

¹School of Life Science, Shanxi Normal University, 1 Gongyuan Street, Linfen City, 041004, China.

²School of Engineering, Shanxi Normal University, 1 Gongyuan Street, Linfen City, 041004. China.

Accepted 23 June, 2019

Abstract

Siderophores, a high-affinity chelating agents for ferric iron, is one of the mechanisms by which biocontrol agents’ act in inhibiting the growth of phytopathogens. Bacillus subtilis QM3, a siderophore producer, is a potential biocontrol agent. In this study, a simple double-layered chrome azurol S agar (SD-CASA) plate assay was developed. We further studied optimal conditions for detection siderophore production by B. subtilis QM3 using various history cultures, pH value, amino acid, and different carbon-nitrogen ratio as four variables. After incubating different history cultures we found out that the LB medium presented strong significant CAS reaction even for 12 h, and with the help of changing variables on SD-CASA plate assisting paper-disc diffusion, strain QM3 from LB medium with Fe³⁺ (10 μmol/L) showed difference interestingly. In addition, CAS reaction and growth reaction also increased with pH 7.0, tryptophan 10 μmol/L and carbon-nitrogen ratio 5:1. The findings on solid medium were similar as that in liquid medium. The SD-CASA assay should be a useful tool for screening potential biocontrol microorganisms by siderophore production.

Key words: A simple double-layered CAS agar assay, paper-disc diffusion, siderophores, Bacillus subtilis QM3.

Advanced Journal of Microbiology Research ISSN 2241-9837 Vol. 14 (4), pp. 001-005, April, 2020. © International Scholars Journals

Full Length Research Paper

Possible involvement of endocyst in tolerance of the resting cyst of Colpoda cucullus against HCl

Yoichiro Sogame, Akemi Kida and Tatsuomi Matsuoka*

Institute of Biological Science, Faculty of Science, Kochi University, Kochi 780-8520, Japan.

Accepted 15 September, 2019

Abstract

Tolerance of the resting cysts of protozoa against gastric acid and proteases is a strategy for surviving in the digestive tract of animals. The present study aimed to examine the protection mechanism against HCl in resting cysts of Colpoda cucullus, which were surrounded by a cyst wall, which is composed of an outermost layer (ectocyst) and several inner layers (endocyst). In addition to water, paraformaldehyde, hydrogen peroxide (H₂O₂) and ethanol may diffuse across the cyst wall, because the cysts hardly showed tolerance against these molecules. However, the cysts showed tolerance against HCl (0.01 to 1 M) and pepsin. The tolerance against HCl disappeared soon after the onset of excystment induction. Electron micrographs of the excysting cells showed that digestion of the endocyst began within 30 min after the onset of excystment induction. The encysting cells surrounded by the ectocyst (3 h after encystment induction) did not show tolerance against HCl, but acquired it just after a first layer of the endocyst was formed beneath the ectocyst (6 h after encystment induction). These results suggest that the tolerance of the resting cyst of C. cucullus against HCl may be acquired by preventing its diffusion across the endocyst, although the possibility that cytoplasmic molecules and the plasma membrane may acquire tolerance has not been ruled out.

Key words: Colpoda cucullus, resting cysts, tolerance, HCl, excystment.

Advanced Journal of Microbiology Research ISSN 2241-9837 Vol. 14 (4), pp. 001-006, April, 2020. © International Scholars Journals

Full Length Research Paper

Domestic wastewater (DWW) influence on secondary metabolite in thyme (Thymus vulgaris L.) under field conditions

Hossein Hassanpour Darvishi¹ and Hossein Aliabadi Farahani²

¹Islamic Azad University, Shahr-e-Qods Branch, Tehran, Iran.

²Young Researchers Club, Shahr-e-Qods Branch, Islamic Azad University, Tehran, Iran.

Accepted 25 August, 2019

Abstract

In order to study domestic wastewater influence on secondary metabolite in thyme (Thymus vulgaris L.) under field condition, this experiment was carried out in Iran. In the field, 15 lysimeters having thyme (T. vulgaris L.) were used, where 1 to 5 lysimeters were irrigated by domestic wastewater and primary drainage water was accumulated. 6 to 9 lysimeters were irrigated by primary drainage water and then, were accumulated by secondary drainage water and we have irrigation 10, 11 and 12 lysimeters by secondary drainage water. In order to compare plants characteristics, in 13, 14 and 15 lysimeters were irrigated by agronomical water. The secondary metabolite in thyme 3.4% increased under irrigation by secondary drainage water into irrigation by agronomical water. The findings may give applicable advice to medicinal and aromatic plants researchers for management and concern on water strategy and estimate of irrigation carefully for increase of quantity and quality yields in medicinal and aromatic plants farming.

Key words: Domestic wastewater, essential oil yield and Thymus vulgaris.

Advanced Journal of Microbiology Research ISSN 2241-9837 Vol. 14 (4), pp. 001-007, April, 2020. © International Scholars Journals

Full Length Research Paper

Transposon mutant of Vigna radiata-nodulating Bradyrhizobium sp. impaired in both resistance to stress conditions and symbiotic performance

Neelawan Pongsilp^1* and Nantakorn Boonkerd²

¹Department of Microbiology, Faculty of Science, Silpakorn University-Sanam Chandra Place Campus, Nakhon Pathom, Thailand.

²School of Biotechnology, Institute of Agricultural Technology, Suranaree University of Technology, Nakhon Ratchasima, Thailand.

Accepted 16 September, 2019

Abstract

Rhizobial strains that nodulate Vigna radiata (mungbean) were examined for their resistance to several stress conditions. One strain of mungbean rhizobia was selected to construct a collection of transposon mutants based on resistance to high temperature (40°C), alkalinity (pH 8.0) and several heavy metals. One mutant that is deficient in resistance to high temperature, alkalinity and zinc was selected to estimate the relation between resistance to stress conditions and symbiotic performance. Southern hybridization analysis showed a single transposon insertion in the mutant strain. The impaired symbiotic performance was observed in the host plants inoculated with the mutant strain as compared with the wild-type strain. This result suggested that genes involved in stress resistance affected the symbiotic ability. The 16S rDNA sequence analysis revealed that the strain is a member of Bradyrhizobium with 98% identity.

Key words: Bradyrhizobium, mutant, transposon, stress tolerance, symbiosis.

Advanced Journal of Microbiology Research ISSN 2241-9837 Vol. 14 (4), pp. 001-007, April, 2020. © International Scholars Journals

Full Length Research Paper

Isolation and characterization of Rhodococcus sp.BX2 capable of degrading bensulfuron-methyl

Minghua Xiong¹, Chunyan Li¹*, Junbo Pan¹, Xiaosong Cheng², and Chuanwu Xi³

¹College of Resource and Environment, Northeast Agricultural University, 150030 Harbin, China.

²College of First Clinical Medicine of Harbin Medical University, 150001 Harbin, China.

³School of Public Health, University of Michigan, 48109 Ann Arbor, MI, USA.

Accepted 30 July, 2019

Abstract

Bensulfuron-methyl (BSM) is a widely applicable sulfonylurea herbicides. However, BSM remains in environment for extended period of time (over 100 days) and causes a series of environmental problems. In this study, BX2, a strain presents high BSM degradation abilities, was isolated from an activated sludge sample using a continuous enrichment method and determined to be a member of the genus Rhodococcus based on its physiobiochemical characteristics and 16S rRNA gene sequence. Strain BX2 degradated 92% BSM from an initial concentration of 20 mg/L within a 7- day incubation at 35℃. The specific degradation rate increased with an increase in the initial BSM concentration and the maximum specific degradation rate obtained was 0.146 mg/(mg•d) at 140 mg/L. BSM degradation by strain BX2 can be presented by Haldane’s inhibition equation and the kinetic parameters were:  vm ax  = 16.75 mg/(mg•d), ks = 7809.36 mg/L and ki = 2.41 mg/L, respectively. These results indicated that the strain BX2 could be an excellent candidate for bioremediation of BSM-contaminated environments due to its high BSM-degradative ability.

Key words: Bensulfuron-methyl (BMS); Rhodococcus sp.BX2; Isolation; Biodegradation.

Advanced Journal of Microbiology Research ISSN 2241-9837 Vol. 14 (4), pp. 001-005, April, 2020. © International Scholars Journals

Full Length Research Paper

Isoniazid resistance of Mycobacterium tuberculosis isolated from human patients

Taha Nazir^1*, Abdul Hameed², Javed Anver Qureshik³ and Bashir Ahmad⁴

¹Riphah Institute of Pharmaceutical Sciences, Riphah International University 7th Avenue G/7-4, Islamabad, Pakistan.

²Department of Microbiology, Quaid-I-Azam University, Islamabad, Pakistan.

³National Institute of Biotechnology and Genetic Engineering, Faisalabad, Pakistan.

⁴School of Pharmacy, University of the Punjab, Lahore, Pakistan.

Accepted 30 July, 2019

Abstract

Isoniazid resistant Mycobacterium tuberculosis strains are a serious threat for successful tuberculosis control programs. Therefore, present study was aimed to figure out the pattern and level of resistance of M. tuberculosis against isoniazid. A total of 172 specimens of sputum, pus and bronchial washings; 70.9% males and 29.1% females with 84.30% pulmonary and 15.69% extrapulmonary tuberculosis were collected from six different sources. The inoculums were prepared using 0.5 Mac Farland turbidity standards. Five concentrations of isoniazid were used in Lowenstein Jensen (LJ) medium that is 3, 6, 9, 12 and + 12 µg/ml for sensitivity testing. Data showed 25 (14.5%) resistant and 147 (85.5%) sensitive M. tuberculosis strains. The growth was not inhibited at first (3 µg/ml) and second (6 µg/ml) drug levels, while 36% isolates inhibited at third level (9 µg/ml), 28% at forth level (12 µg/ml) and 24% at fifth level (10 µg/ml) and 12% at higher than fifth Level (> 12 ug/ml). These incorporated drug concentrations are higher than therapeutic index and not recommended in actual clinical practice. It is thus obvious to explore some other effective chemotherapeutic agents, modify combinations or figure out more effective procedures to stop morbidity and mortality due to isoniazide resistance of M. tuberculosis.

Key words: Isoniazid, mycobacterium tuberculosis, resistance, Lowenstein Jensen medium.