Open Access Original Research Article

Persistence and Comparative Pesticidal Potentials of Some Constituents of Lippia adoensis (Hochst. ex Walp.) (Lamiales: Verbenaceae) Essential Oil against Three Life Stages of Callosobruchus maculatus (Fab.) (Coleoptera: Bruchidae)

Mazarin Akami, Changying Niu, Hamada Chakira, Zhenzhong Chen, Tigamba Vandi, Elias Nchiwan Nukenine

Biotechnology Journal International, Page 1-16
DOI: 10.9734/BBJ/2016/26087

Over the past decades, the development of an alternative and eco-friendly pest control strategies has become a public concern for the sake of mankind. Plant essential oils are complex mixtures of volatile organic compounds, which play indispensable roles in the environment, for the plant itself, as well as for humans.

Aims: The objectives of this study were (i) to identify and report the volatile organic compounds of Lippia adoensis (Hochst. Ex Walp.) (Lamiales: verbenaceae) essential oil (EO, herein after) and to compare the bioactivity of its four major compounds with the crude EO at relatively low dosages on some fitness parameters of Callosobruchus  maculatus (F.) (Coleptera: Bruchidae), (ii) to test the persistency of each compounds over time, and (iii) to evaluate the type of interaction of the major constituents of the EO (whether antagonistic, synergistic or additive) in order to project the biological interaction of the whole compounds.

Study Design: Young leaves of L. adoensis were randomly collected in Mbe locality (Ngaoundere-Cameroon) for EO extraction which was then analysed by the means of Gas Chromatography (GC-FID) coupled with Mass Spectrometry (GC-MS). Bioassays consisted of three shelves treatments for adult mortality, eggs laying, larval development and progeny production. A complete randomized design (CRD) with five replications was set for each treatment.

Places and Duration of Study: Laboratory of Biology of the Faculty of Science, University of Ngaoundere (Cameroon) and Pest Control laboratory of Professor Niu Changying HZAU, Wuhan (China) from February 2014 to January 2016.

Methodology: Essential oil was extracted with a Clevencher-type apparatus, hydrodistilled and air-dried. Gas Chromatography-Flame Ionization Detector (GC-FID) and Gas Chromatography coupled with Mass Spectrometry (GC-MS) were carried out to analyze the constituents. The toxicity of crude EO and its four major constituents was evaluated at 0.5, 5, 10, 20 and 40 µL/g. Ten glass jars (volume 800mL)  containing 50 g of cowpea seeds were prepared. After treatment, ten couples of C. maculatus aged 1-7days were randomly selected and separately introduced in each glass jar and kept at 22.72±1.06°C, 83.73±1.28% RH. Control jars were treated only with pure acetone. Each treatment was replicated five times. The exposure lasted for six days post treatment. Data on adult’s mortality, eggs laying, larvae and progeny production were assessed and monitored.

Results: The GC–MS analysis allowed the identification of 43 volatile components representing 93.54% of total oil. The major components were Thymol (22.01%), Thymol-acetate (15.21%), para-cymene (13.85%) and Triacetin (9.131%).

The crude EO suppressed adults, completely inhibited eggs laying and adult emergence at 5 and 10

Open Access Original Research Article

Production and Application of Agar-based Slow-release Fertilizers, in the Bioremediation of Petroleum Hydrocarbon-impacted Soil

T. Sampson, C. J. Ogugbue, G. C. Okpokwasili

Biotechnology Journal International, Page 1-13
DOI: 10.9734/BBJ/2016/25955

Aims: The study was carried out to determine the potentials of novel slow-release fertilizers (SRF) in the bioremediation of petroleum hydrocarbon-impacted soil, in order to determine their potentials in the bioremediation of petroleum-impacted sites and as well evaluate the effect of nutrient concentration on the rate of bioremediation.

Study Design: A marine biopolymer (agar agar) was used as a coating for soluble NPK fertilizer in slow-release formulations (capsular and granular form).

Place and Duration of Study: This study was carried out in the Environmental Microbiology Laboratory, University of Port Harcourt, Nigeria, between January and June 2015.

Methodology: The contaminated soil sample was recreated in four clean plastic containers and labeled A - D, as follows: Sample A = 300 g Soil + 20 g NPK Capsular SRF; Sample B = 300 g Soil + 20 g NPK Granular SRF; Sample C = 300 g Soil + 20 g Direct NPK; Sample D = 300 g Soil (without fertilizer - control). The determination of the effect of SRF on the population dynamics of total aerobic heterotrophic bacteria (THB) and hydrocarbon utilizing bacteria (HUB) was achieved through the use of nutrient agar (spread plate technique) and mineral salts agar (vapour phase transfer technique) in the enumeration of THB and HUB respectively.

Results: After a 42-day period, there was a significant difference, (p <0 .05) in the percentage loss of total petroleum hydrocarbon between the various treatment options. Sample D had the least percentage loss (33.6%) of total petroleum hydrocarbon, Sample A (50.5%), Sample B (73.1%) and Sample C had the highest percentage loss of 74.83%. The various bacterial counts (THB and HUB) increased progressively with increase in nutrient concentration.

Conclusion: The results revealed the applicability and effectiveness of slow release fertilizers in the bioremediation of hydrocarbon impacted soil. These novel SRFs are also recommended for their applicability in the bioremediation of water and sediments.

Open Access Original Research Article

Toxicological Effects of Plastic Composted Soil on Nitrifying Bacteria

E. I. Atuanya, A. O. Dave-Omoregie, U. Udochukwu, J. Inetianbor

Biotechnology Journal International, Page 1-7
DOI: 10.9734/BBJ/2016/26234

Aim: The aim of this study was to evaluate the toxicological effects of plastic composted soil on some nitrifying bacteria which are Nitrosomonas sp. and Nitrobacter sp.

Methodology: Five plastic composted soil samples were collected from different locations within the Edo State Waste Management site located at Iyowa in Benin City which were merged to form a composite sample. Nitrosomonas sp. and Nitrobacter sp. were isolated from the soil samples. Plastic composted soil concentrations were prepared for LC50 and EC50 determination. Nitrobacter and Nitrosomonas acute toxicity test was carried out. Initial nitrite concentrations were determined and plates of Winograsky agar were immediately inoculated by spread plate techniques. Nitrite accumulation and utilization were also determined and inoculation by spread plate method was carried out from the various plastic composted soil concentrations after 1 h, 2 h, 3 h and 4 h time intervals. Plates were incubated at room temperature (28+/- 2°C) for 24 h. The percentage inhibition of bacteria (Nitrosomonas sp. and Nitrobacter sp.) was determined using the probit regression analysis in Excel Microsoft.

Results: The EC50 values for Nitrosomonas sp. are as follows; 0.52, 0.82, 1.11 and 1.23 with LC50 values of 27.47, 24.14, 19.74 and 16.73. It was observed that the EC50 values were very low which increased gradually with time, this suggest that there was a high percentage inhibition of Nitrosomonas sp. thereby altering and reducing the percentage nitrite accumulation by the bacteria.  The EC50 values for Nitrobacter sp. are 52.00, 81.72, 111.31 and 123.13 and LC50 values are 25.04, 23.93, 15.94 and 13.39. The EC50 values for Nitrobacter sp. were high which indicates that there was high nitrite utilization by Nitrobacter sp. as the percentage inhibition gradually decreased with exposure time. The coefficient of determination showed that the bacteria response which could be either inhibition, utilization or accumulation greatly depends on the amount/concentration of the plastic contaminants present in the test soil sample.

Conclusion: The result from this study shows that the EC50 determination was more sensitive than the LC50 determination for Nitrosomonas sp. and that the LC50 determination was more sensitive than the EC50 determination for Nitrobacter sp.  Also that the populations of Nitrosomonas sp. were more sensitive to the plastic contaminants than the populations of Nitrobacter sp. The results obtained from this study suggest that autotrophic transformation by nitrifying bacteria which enhances soil fertility may be hindered in an ecosystem polluted with plastics as nitrification processes will be altered.

Open Access Original Research Article

In vitro Cytological Studies of Leaf Callus Cultures of Orthosiphon aristatus (Blume) Miq

P. Dorothy, M. S. Sudarshana, A. R. Nissar, H. V. Girish

Biotechnology Journal International, Page 1-6
DOI: 10.9734/BBJ/2016/25638

The study was carried out to unravel the in vitro cytological behaviour of leaf callus cultures of Orthosiphon ariststus (Blume) Miq. The cultures were raised using leaf explants on Murashige and Skoog (MS) medium supplemented with different growth regulators like auxins (2,4-D, IAA, NAA) and cytokinin (BAP) alone and in different concentrations and combinations. Best callusing from the leaf explants was achieved in 2,4-D supplemented MS medium at 5 mg/l concentration. Cytogenetic analysis of the chromosomal variations was carried out for primary cultures as well as 3-month-old callus cultures. The chromosome number did not show variations and the cells studied were observed to be diploid (2n= 28) in nature. Among the numerical observations induced, polyploid cells were the most frequent. The frequency of bridges was observed among the other structural changes. The composition and concentration of the growth regulators was found to affect chromosomal instability with multinucleate, multinucleolate and embryogenic masses. These observations indicate that genetic variations may arise during cell cultures.

Open Access Review Article

Current Opportunities and Challenges of Next Generation Sequencing (NGS) of DNA; Determining Health and Diseases

Carlo P. J. M. Brouwer, Thuy Duong Vu, Miaomiao Zhou, Gianluigi Cardinali, Mick M. Welling, Nathalie van de Wiele, Vincent Robert

Biotechnology Journal International, Page 1-17
DOI: 10.9734/BBJ/2016/25662

Many publications have demonstrated the huge potential of NGS methods in terms of new species discovery, environment monitoring, ecological studies, etc. [24,35,92,97,103]. Undoubtedly, NGS will become one the major tools for species identification and for routine diagnostic use. While read lengths are still quite short for most existing systems ranging between 50 bp and 800 bp, they are likely to improve soon. This will enable easier, faster, and more reliable contig assembly and subsequent matching against reference databases. When data generation is no longer a bottleneck, the storage, speed of analysis, and interpretation of DNA sequence data are becoming the major challenges. Also, the integration or the use of data originating from diverse datasets and a variety of data providers are serious issues that need to be addressed. Poor sequence record annotations and species name assignments are known problems that should be instantly addressed and would allow the creation of reference databases used for routine diagnostics based on NGS. Samples with huge amounts of short DNA fragments need to be analyzed and compared against reference databases in an efficient and fast way.  Although a number of solutions have been proposed by Industry; offering commercial software, there still remain hurdles to take. One of the challenges that we need to address is data upload from client’s computers to central or distributed data storage and analysis services. Another one is the efficient parallelization of analyses using cloud or grid solutions. The reliability and up-time of storage and analyses facilities is another important problem that need to be addressed if one wants to use it for routine diagnostics. Finally, the management, reporting and visualization of the analyses results are among the last issues, but not the least challenging ones. Considering the constant growth of computational power and storage capacity needed by different bioinformatics applications, working with single or a limited number of servers is no longer realistic. Using a cloud environment and grid computing is becoming a must. Even single cloud service provider can be restrictive for bioinformatics applications and working with more than one cloud can make the workflow more robust in the face of failures and always growing capacity needs. In this white paper we review the current state of the art in this field. We discuss the main limitations and challenges that we need to address such as; data upload from client’s computers to central or distributed data storage and analysis services; efficient parallelization of analyses using grid solutions; reliability and up-time of storage and analyses facilities for routine diagnostics; management, retrieving and visualization of the analyses results.