Open Access Original Research Article

A Study of Bacteriological and Physicochemical Characteristics in Soils of Auto-mechanic and none Auto-mechanic Workshop Soils from Selected Areas in Calabar Metropolis

D. R. Tiku, B. E. Asikong, S. O. Idire

Microbiology Research Journal International, Page 1-14
DOI: 10.9734/BMRJ/2016/23596

The research study was aimed at investigating physicochemical and bacteriological characteristics of auto-mechanic and none auto-mechanic workshop soil samples. Auto-mechanic and non auto-mechanic workshop environments were randomly sampled within Calabar Metropolis. The study was completed within a period of six months. Standard microbiological methods were used to isolate, characterize and identify bacteria from the collected soil samples. The mean heterotrophic bacteria counts were higher in the auto-mechanic workshop soils compared to their non auto-mechanic workshop soil counterpart. Bacteria isolates from the auto-mechanic mechanic workshop soil samples were identified as species of Aeromonas, Serratia, Klebsiella, Corynebacterium, Yersinia, Shigella, Enterobacter and Escherichia coli, while those isolated from the none auto-mechanic workshop soils were identified as Citrobacter, Yersinia, Bacillus and Serratia. Comparison of the mean physicochemical parameters of the auto-mechanic workshop and non auto-mechanic soil samples showed significantly lower values of pH and available phosphorus in the auto-mechanic workshop soils whereas C:N ratio, calcium, total hydrocarbon concentration effective carbon exchange capacity and base saturation percentage values were significantly (P<0.05) higher in the auto-mechanic workshop soil samples. The concentration of heavy metals varied widely among the location studied. The mean Zn, Cu, Fe, V, Ni, Cd, Pb, Co, Cr were higher in the auto-mechanic workshop soil samples than in the none auto-mechanic soil samples. However, the total hydrocarbon values for the studied auto-mechanic soil samples showed that the mean values of 5266.7 mg/kg, 4413.2 mg/kg, 3130 mg/kg and 4514.4 mg/kg (AMT, AMM AME, and AMI) were above the recognized biogenic value of 50 mg/kg reported by DPR (1991), as these is environmentally significant and indicative of gross contamination which could in turn stimulate a wide variety of environmental issues.

Open Access Original Research Article

Necropsy Findings and Histopathological Changes in Dogs with Conjunct Experimental Trypanosoma congolense and Ancylostoma caninum Infections

R. I. O. Nwoha, I. R. Onoja

Microbiology Research Journal International, Page 1-8
DOI: 10.9734/BMRJ/2016/27741

Trypanosoma congolense and Ancylostoma caninum are parasitic diseases of dogs which commonly occur in the south-eastern part of Nigeria. There appear to be dearth of information on the histopathological changes in dogs with mixed infections of both parasites which necessitated the study. There were marked necropsy and histopathological changes in the vital organs of 4 dogs experimentally infected with both Ancylostoma caninum (A. caninum) and Trypanosoma congolense (T. congolense). Trypanosomacongolense was inoculated post establishment of A. caninum infection in the dogs. The prepatent period of T. congolense was 10±2.0 days and 14±1.2 days in A. caninum. The disease ran a course of 45 days before death. Necropsy findings include, haemorrhages in the stomach mucosa, splenomegally, enlargement of the heart, congested and emphysematous lungs, congested and necrotic areas on the liver and normal kidneys. The histopathological changes were classified as degenerative, emphysematous, infiltrations of immune complexes and anaemia. The gross morphology of organs at necropsy may not reveal the degree of histopathological changes. The study however reveals extensive histopathological changes in vital organs of dogs with mixed infections of T. congolense and A. caninum.

Open Access Original Research Article

Plant Growth Promotion and Biocontrol Potential of a Streptomyces sp. Strain N3-3b Isolated from the Rhizosphere of Chakhao, a Black Rice Variety of Manipur, India

Debananda S. Ningthoujam, Shamjetshabam Babeeta Chanu, K. Tamreihao, Rajkumari Lynda, Khaidem Aruna Devi, Ningthoukhongjam Jeeniita

Microbiology Research Journal International, Page 1-11
DOI: 10.9734/BMRJ/2016/27422

Aims: To isolate and investigate actinomycete strains from rhizospheric soil of Chakhao (black rice) in Manipur, India for biocontrol and plant growth promoting activities.

Study Design: Dual culture, plant growth promoting activities and vigor index.

Place and Duration of Study: Microbial Biotechnology Research Laboratory (MBRL), Department of Biochemistry, Manipur University, India, between August 2010 and July 2013; re-analyzed and reviewed during August 2015-May 2016.

Methodology: Isolates were screened for biocontrol activity and one strain which showed significant antagonistic potential was selected for further studies. The selected strain was subjected to plant growth promoting traits such as IAA, ammonia and siderophore production, and inorganic phosphate solubilization. It was further assayed for rice seed germination and growth of rice seedlings under in vitroconditions. Characterization of the strain was also done.

Results: Among 122 putative actinomycete isolates, 9 exhibited antagonistic activity against rice fungal pathogens. N3-3b was selected as the most promising biocontrol strain for further studies. The strain exhibited plant growth promoting traits including IAA production, phosphate solubilisation and ammonia production. It promoted seed germination and significantly enhanced growth of seedlings (Vigor index) under in vitro conditions. Based on the phenotypic characteristics and 16S rRNA gene sequence analysis, the strain N3-3b was characterized as a member of the genus Streptomyces.

Conclusion: Strain N3-3b could be a potential candidate for development as bioinoculant for rice cultivation.

Open Access Original Research Article

Inhibition of the Mex Pumps of Pseudomonas aeruginosa with a Newly Characterized Member of Peptidomimetic Family

Asiyeh Avakh, Karamatollah Rezaei

Microbiology Research Journal International,
DOI: 10.9734/BMRJ/2016/27374

Aims: Efflux pumps, particularly resistance-nodulation-division family such as Mex pumps in Pseudomonas aeruginosa, are the major contributors to multidrug resistance in Gram-negative bacteria. Since the well-known efflux pump inhibitor (EPI), phenylalanine-arginine β-naphthylamide (PAβN), is a substrate of cathepsin C (a proteolytic enzyme), inhibitory effects of similar substrates of this enzyme, proline-arginine 4-methoxy-β-naphthylamide (PA4MβN) and Nα-Benzoyl-DL-arginine β-naphthylamide (BAN), were investigated as possible new EPIs. Additionally, the probable EPI activities of three different alkaloids (noscapine, caffeine and ergotamine) against Mex-pump expressing strains were also evaluated mainly based on their structural similarities to major EPIs.

Methodology: MPC(minimum potentiating concentrations) of mentioned compounds in combination with levofloxacin (LVX) were screened against a wild type (PAO1) and two different Mex-pump overexpressing P. aeruginosa strains (nalB and nfxB). The most synergizing compound was further validated by the checkerboard assay for its EPI potency against strains overexpressing or lacking different Mex-pumps. The frequencies of emergence of LVX-resistance strains when it was used either alone or in combination with the suggested EPI were also compared against each other.

Results: PA4MβN caused significant increase in LVX activity against PAO1 and different Mex-pump overexpressing P. aeruginosa strains showing a significant decrease in the intrinsic (8-fold) and acquired (16-fold) resistances. Interestingly, PA4MβN fully prevented further emergence of P. aeruginosa mutants highly resistant to fluoroquinolones.

Conclusion: A new compound from peptidomimetic family (PA4MβN), which is also a substrate of cathepsin C, was introduced in the current study as an effective EPI against Mex pumps from P. aeruginosa.

Open Access Original Research Article

Effect of Cyanobacteria on Reducing Damping-off and Root Rot Incidence in Lupine Plants, New Valley Governorate, Egypt

Montaser Fawzy Abdel-Monaim, Mohamed Mahmoud. Mazen, Marwa Abdel-Alla Mahmoud Atwa

Microbiology Research Journal International, Page 1-14
DOI: 10.9734/BMRJ/2016/27883

This study was conducted to investigate the suppression effect of four cyanobacteria species viz. Nostoc muscorum, Oscillatoria agardhii, Spirulina platensis and Anabaena sphaerica, against Rhizoctonia solani, Fusarium solani and Macrophomina phaseolina as the causal agent of lupine damping-off and root rot diseases under greenhouse and field conditions. Cyanobacterial secondary metabolites have a diverse antagonistic activity that lead to disintegration of microbial growth. All cyanobacteria were significantly suppressed of the tested pathogenic fungi in vitro. The reduction in the linear growth of the tested fungi was differed depending of type of solvent extract. Acetone extract of O. agardhii was recorded the highest growth reduction of all tested pathogenic fungi.

Contents of indole actetic acid (IAA), total phenol and flavonoid compounds and protease enzyme activity showed an increase in the extracts of N. muscorum, O. agardhii than the extracts of S. platensis and A. sphaerica. Also, acetone extract of all tested cyanobacteria was recorded the highly secondary metabolites than methanol and water extracts. Treated lupine seeds (cv. Giza 1) with any of the cyanobacteria extracts before sowing results significantly reduction of damping-off and root rot incidence compared with untreated seeds under pot and field conditions. On the other hand, treating lupine seeds with cyanobacteria extracts increased plant growth and yield parameters during both growing seasons (2014-2015 and 2015-2016). In general, O. agardhii followed by N. muscorum highly reduced damping-off and root rot incidence both in pot and field experiments as well as increase of growth (pant height and No. of branches plant-1) and yield parameters (No. of pods plant-1, No. of seed plant-1, seed index (gm) and total yield fed.-1 (Kg) in field. Also, acetone extract more effective in this respect than methanol or water extracts.

Open Access Original Research Article

The Effects of Different Storage Temperatures on the Microbial, Physicochemical and Organoleptic Quality Changes in the Shellfish "Ngolo" (Thais califera) from Nigeria

Boma O. Oruwari, Bernard J. O. Efiuvwevwere

Microbiology Research Journal International, Page 1-11
DOI: 10.9734/BMRJ/2016/27698

Aims: To investigate the effects of different storage temperatures (-15±2°C; 4±2°C and 29±2°C) on quality changes in ‘Ngolo’ (Thais califera) to evaluate the potential enhancement or otherwise of its domestic and global trade.

Study Design: “Ngolo” samples were subjected to different temperatures and evaluated for microbiological, physico-chemical and organoleptic changes during short and long-term storage.

Place and Duration of Study: Department of Microbiology (Food and Industrial Division), University of Port Harcourt and Research and Development Division, Nigerian National Petroleum Corporation (NNPC), Moscow Road, Port Harcourt, Nigeria between January 2006 and December 2008.

Methodology: Freshly shucked “Ngolo” samples were divided using sterile polyethylene bags into sub-samples of 150 g per bag and stored at (-15±2°C; 4±2°C and 29±2°C) respectively and analysed at daily or weekly intervals for microbial, physico-chemical and organoleptic quality attributes.

Results: Variations in quality attributes of “Ngolo” samples were induced by the temperatures resulting in significant (P=.05) minimum total viable counts (2.12 log CFU/g) in samples stored at -15±2°C compared with 8.72 log CFU/g in samples stored at 29±2°C. Little or no change in pH occurred within two weeks in samples stored at  -15±2°C and 4±2°C respectively but decrease in pH within 24h occurred in samples stored at 29±2°C. Total volatile nitrogen (TVN) and trimethylamine (TMA) contents remained low (32 mgN/100 g TVN and 25 mgN/100 g TMA) in samples stored at -15±2°C and were acceptable throughout storage while the contents of those stored at 29±2°C increased significantly (P=.05) from day 0 to 72 mgN/100 g and 48 mgN/100g respectively on day 4 and were rejected within 24h. Significant (P=.05) positive correlations between TVCs and TVN occurred indicating their usefulness for prediction of quality changes in “Ngolo” (and could be applied to other related seafoods).

Conclusion: Overall, the quality attributes of samples stored at -15±2°C remained significantly (P =.05) acceptable throughout storage thereby enhancing their potential for international food trade.