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Annals of Applied Microbiology & Biotechnology Journal

The Composition and Interaction of the Gut Microbiota in Four Species of Wild Dragonflies

[ ISSN : 2576-5426 ]

Abstract Introduction Materials and Methods Results Discussion Acknowledgements References
Details

Received: 20-Dec-2019

Accepted: 08-Jan-2020

Published: 10-Jan-2020

Lingzhen Cao* and Xiangxia Bu 

College of Life Science, Jiangxi Normal University, China

Corresponding Author:

Lingzhen Cao, College of Life Science, Jiangxi Normal University, Ziyang District #99, Nanchang, CN 330022, China, Tel: 86-079188120391, E-mail: clzclz1011@163.com

Keywords

16S rRNA; Gut microbes; Diversity Analysis; Dragonfly

Abstract

Dragonflies are natural enemies for a host of insects, which mainly feed on mosquitoes and other insect pests. Bacterial communities in the dragonfly gut impact on host survival, ecology and evolution; however intestinal microbiota diversity in these insects is not well understood. In this study, we used the Illumina Miseq PE300 platform to characterize intestinal microbiota communities in four dragonfly species(Pantala flavescens Fabricius; Orthetrum sabino Drury; Coenagrion dyeri Fraser and Brachythemis contaminate Fabricius). Our results showed that microbiota densities and species in the dragonfly gut were rich and varied; these microbes showed complex interrelationships suggesting the host species had a major impact on gut community richness. The diversity of intestinal microbes may be related to the species and the habitats of dragonflies. Proteobacteria and Firmicutes were common in the four samples and represented core members of the dragonfly gut microbiota, accounting for approximately 99.00%. At the genus level, Serratia (83%), Lactococcus (41.5%), Hafnia (55.8%) and Lactococcus (71.7%) were dominant populations in the four groups (d1, h1_1, h1 and q1). Our results provide a basis for future research on gut bacteria functions in the dragonflies.

Introduction

Insects have successfully evolved to become the most diverse and abundant animal clade in terms of numbers of species, ecological habits and biomass [1]. Their evolutionary success has depended on their beneficial association with microorganisms, especially gut microorganisms [1-3]. Insect-microbes as mediators may be critical in the agriculture, medicine and ecology [4-6].

The diversity and versatility of insect-bacteria interactions represents enormous medical and agricultural potential in terms of modulation and control mechanism of insect populations [7]. Insects are responsible for massive agricultural losses and for pollination of many food crops, and microbes associated with pollinators and herbivores impact on crops, but they can also cause large agricultural losses [1].

Insects have evolved effective immune responses to combat pathogen infections, although insects, including honey bees, lack acquired immune responses [8-10]. Previous research has reported that gut microbes regulate host innate immunity and affects pathogen or parasite susceptibility [11-14]. In addition to beneficial effects, insect gut microbes may be harmful to their hosts [15,16]. Alterations in the gut microbiota of Drosophila, induced by the host’s deregulated immune genotype, may lead to host mortality [17]. Gut bacteria perturbations by antibiotics could increase susceptibilities to opportunistic bacterial pathogens and decrease survival of some insects, e.g. honey bees [18].

Insect gut microbiota has been analyzed using both culture-dependent and culture-independent methods [19-23]. Traditional culture methods often produce biased results since approximately 99% of all bacteria are uncultivable [24]. However, the development of meta-taxonomic analyses, based on high throughput sequencing of 16S rRNA, has greatly facilitated the profiling of microbial diversities in populations, when compared to traditional cultured-dependent and conventional molecular methods [25]. These comprehensive 16S rRNA sequence analysis projects provide dramatic insights into total bacterial diversity and metabolic activity of insect-associated microbial communities [26].

Dragonflies are important predators in both freshwater and terrestrial invertebrate foodwebs and are believed to be generalist predators that feed on a wide diversity of insects [27]. This dietary diversity should be associated with diverse gut microbial communities. The main objective of our study was to investigate bacterial diversity and composition of intestinal microbes and assess potential roles of gut bacteria in the digestion of four dragonfly species.

Materials and Methods

Ethics Statement

In our study four dragonfly species were investigated; Pantala flavescens Fabricius (q1); Orthetrum sabino Drury (h1); Brachythemis contaminate Fabricius (h1_1) and Coenagrion dyeri Fraser (d1). The flight abilities of the four species of dragonflies gradually diminished. At the same time, the four species are widely distributed throughout China, with no significant threats presently affecting these species (https://www.iucnredlist.org/search?taxonomies=100547 & search Type=species). No permits were required for catching dragonflies.

Sample collection

In July 2019, twenty dragonflies (five from each species) were caught using butterfly nets, at Jiangxi Normal University (28°66′87″N, 115°97′93″E), Nanchang city, Jiangxi province, PR China. P. flavescens and O. obsitina were caught in a meadow, while C. dyeri and B. contaminate adults were caught near a pond. Specimens were brought to the laboratory and were washed using 70% ethanol, followed by washing in distilled water [23]. Specimens were then stored at -20 until processing.

DNA extraction, amplification and high throughput Illumina sequencing

To determine gut bacterial composition, the gut was dissected and stored in a 1.5 ml tube for DNA extraction. Bacterial genomic DNA was extracted using the Wizard® Genomic DNA Purification Kit (Promega, Fitchburg, WI, USA) following manufacturer’s instructions. Extracted DNA was checked using 1% gel agarose electrophoresis, while the concentration and purity were determined using the NanoDrop 2000 Spectrophotometer (Thermo Fisher Scientific, Waltham, MA, USA). DNA from the four species was used as a temple to amplify the V3 - V4 region of the bacterial 16S rRNA gene using universal primers; 338F (ACTCCTACGGGAGGCAGCAG) and (GGACTACHVGGGTWTCTAAT). PCR reactions were performed on a GeneAmp® PCR 9700 System (ABI, Foster City, CA, USA) as previous described [28]. Once generated, PCR products were checked by 2% gel electrophoresis and extracted and purified using the DNA Gel Extraction Kit (Tiangen, Beijing, China) following manufacturer’s instructions. The purified DNA products were quantified and equalized using a TBS-380 Mini Fluorometer (Turner BioSystems, Sunnyvale CA, USA). The pooled products were submitted to Shanghai Majorbio Bio-Pharm Technology Co., Ltd (Shanghai, China) for 16S rRNA sequencing, using the Illumina Miseq PE300 platform (Illumina Corporation, San Diego, CA, USA).

Nucleotide sequences for all bacterial datasets were uploaded to NCBI (http://www.ncbi.nlm.nih.gov/) Short Read Archive, under the accession number PRJNA559000.

Data analysis

Raw Illumina read fastq files were de-multiplexed and quality filtered by Trimmomatic, and merged by FLASH [28]. We eliminated low quality sequences (quality scores lower than 20 over a 50 bp sliding window, primer mismatches lower than 2 and tags less than 50 bp). The length of overlap in merged sequences was over 10 bp and the wrong pair rate was low, 0.2. Usearch (version 7.1 http://drive5.com/uparse/) was applied to cluster the OTUs (Operational Taxonomic Units) at the identity threshold of 97%, and chimeric sequences were identified and removed by UCHIME [29,30]. Community alpha-diversity was analyzed using community diversity (Shannon and Simpson) and community richness (Chao and Ace) was analyzed using Mothur version v.1.30.1 [31].The Good’s coverage Shannon-Wiener curve and rarefaction curve were generated based on Mothur 1.30.1 software [31] with a 97% similarity. Phylogenetic beta diversity measures (hierarchical cluster tree and Non-MetricMulti Dimensional Scaling (NMDS), Venn diagrams, heatmap figures and rank-abundance curves were performed in vegan packages in R (version 3.1.2).

Phylogenetic affiliations from representative sequences were accessed using the Ribosomal Database Project(RDP) classifiers [32] against the Silva 16S rRNA database [33] with a confidence threshold of 70%. The community composition of each sample was analyzed for multiple taxa (phylum, class, order, family, genus and species). Bacterial similarities in different samples were calculated using hierarchical cluster analysis and un weighted UniFrac principal co-ordinates analysis (PcoA).

Results

Characteristics of sequencing data

From four samples, approximately 206,201 reads, with an average length of 449.28 bp were generated,using the Illumina Miseq sequence platform.Representative sequences for all OTUs are available (Short Read Archive, with the accession number PRJNA559000).Sequences were clustered into 115 OTUs and the Good’s coverage for observed OTUs was 99.99% ± 0.01% (Table 1).The alpha diversity for species richness (Chao), evenness (ACE) showed the highest diversity in the q1 sample, and the lowest diversity was in the h1 sample. Shannon’s diversity index and Simpson index showed the highest diversity in the h1-1 sample and the lowest diversity in the d1 sample (Table 1).

Table 1: MiSeq sequencing results and diversity estimates for each sample. * indicates 97% similarity.

Sample ID Reads Diversity estimates*
OUT ACE Chao coverage Shannon Simpson
Coenagrion dyeri 44572 50 53 54 0.999865 0.77 0.6954
Orthetrum sabino 44572 26 30 28 0.999888 1.24 0.3934
Brachythemis contaminate 44572 48 50 48 0.999955 1.91 0.2447
Pantala flavescens 44572 86 86 86 1 1.32 0.4339

The rarefaction curve indicated large variations in the total number of OTUs (Figure 1).

Figure 1 Rarefaction curves of OTUs in a 97% similarity boxplot for each sample.

The rarefaction curves all tended to approach saturation plateau,thereby indicating that the depth of sequencing was adequate for intestinal microbiota investigations.Among the four samples, the h1 sample had the lowest OTU density, followed by h1-1 and d1.

Taxonomic composition of samples from intestinal microbiota

Sequences that could not be classified into any known groups were unclassified.Bacterial OTUs were clustered into three phyla; Proteobacteria, Firmicutes and Bacteroidetes.Proteobacteria and Firmicutes were common to the four samples and represented core members of the dragonfly gut microbiota, accounting for 99.00% of total sequences (Figure 2).

Figure 2 Phylum distribution of gut samples.Other phyla were present but with less than < 0.01% abundance.

The d1 and h1 samples were dominated by Proteobacteria (93.28% and 98.89%,respectively).The q1 sample was dominated by Firmicutes (74.52%) and the h1-1 sample was dominated by Proteobacteria (50.52%) and Firmicutes (48.58%). Firmicutes, in the different samples showed high variability ranging from 74.52% to 1.11%. The final phyla, Bacteroidetes were also present, but with very low abundance (< 1%), except for q1 (approximately 1.1%).There were 13 identifiable bacterial genera which made up abundances of 98%, 100%, 100% and 98% in the four samples (Supplementary Figure 1). At the genus level, the d1 sample was dominated by Serratia (83%),Lactococcus (6.28%), Pantoea(3.41%),Enterobacter (3.24%), Proteus (1.85%) and other genera with less than 1% abundance.The h1-1 sample was dominated by Lactococcus(41.5%),Aeromonas (33.2%),Enterobacter(5.7%), Enterobaxteriaceae_unclassified (5.2%), Clostridium (4.9%), Pantoea (2.2%), Providencia (2.1%), unclassified genera (4.7%) and other genera with less than 1% abundance.The h1 sample was dominated by Hafnia (55.8%), Enterobacter (27.1%),Stenotrophomonas (7.90%),Pantoea (3.1%),Raoultella (2.7%),Serratia (1.9%) and other genera with less than1% abundance.The q1sample was dominated by Lactococcus (71.7%),Enterobacter (20%), Enterococcus (1.7%),Pantoea (1.5%),unclassified genera (4.3%) and other genera with less than 1% abundance (Supplementary Figure 1).

Difference and similarity of gut microbiota among four groups

Venn analysis was used to depict the shared or unique OTUs at the genus level. There was a total of 115 OTUs and 11 of them (10.4%) were shared genera (Figure 3).

Figure 3 Venn diagram showing bacterial genera detected in the four samples.Overlaps between samples are indicated by the arrangement of circles..

Q1 community contained more bacterial varieties (86 genera) than d1 (50), h1(26) and h1-1 (48). An overlap between the different communities was observed in Figure 3. The largest overlap was found between d1 and q1 libraries shared 44 of 92 OTUs; the q1 and h1_1 library shared 26 of the 108 (24%) OTUs, the q1 and h1 libraries with shared 22 of 90 (24%) OTUs. The h1 and h1_1 libraries shared 14 of the 81(17%) OTUs; d1 and h1 libraries shared 19 of 57 (33%) OTUs; d1 and h1_1 libraries shared 17 of 81 (21%) OTUs; h1, h1_1 and q1 libraries shared 13 of 94 (14%) OTUs, h1, h1_1 and d1 libraries shared 11 of the 85 (13%) OTUs, h1, q1 and d1 libraries shared 17 of the 94 (18%) OTUs, H1-1, q1 and d1 libraries shared 17 of 97 (18%) OTUs; h1, h1-1, q1 and d1 libraries shared 11 of 115 (9%) OTUs. D1 had 4 special OTUs, h1 had 1 special OTUs, h1-1 has 21 special OTUs and q1 had 30 special OTUs.

Based on genera relative abundance, genera with an average abundance of >1% in at least one sample were defined as predominant [34].There were three shared dominant genera (Enterobacter,Pantoea and Lactococcus) among the four samples OTUs, h1 had one special OTU, h1-1 had 21 special OTUs and q1 had 30 special OTUs (Figure 3).

PcoA was used to determine similarities in gut microbial communities in the four samples. Un-weighted UniFrac distance PcoA showed that the four samples were separate from each other, and that d1 was the most distinct (Supplementary Figure 2). Nonmetric multidimensional scaling (NMDS) based on Beta diversity also revealed distinct differences in species abundance across the four samples (Supplementary Figure 2).

Sample ID We also assessed similarities in gut microbiota at the phyla and genera level in all samples. Cluster analyses showed similar data (Figure 4).

Figure 4 (A) Hierarchical cluster tree of samples based on intestinal microbiota composition. Bray-Cutis community similarity indices was used for community similarities and cluster analysis. (B) Major phyla distribution of gut microbiota among samples and the hierarchical cluster tree.

Q1 and h1 samples were clustered first, then h1-1 was clustered as one branch of (q1 + h1), and finally the d1 sample was clustered as one branch with groups of ((q1+ h1) and h1-1)) communities.

The network of co-occurrence of 16S rRNA gene function

Gut bacterial communities cannot be treated as single functional entities; the igraph R package was used to perform network analysis and visualization of OTUs. Gut microbial networks (Figure 5) consisted of 115 nodes (OTUs).

Figure 5 Co-occurrence network of 115 OTUs.

The OTUs were highly connected, revealing complex interrelationships between OTUs.

Discussion

Dragonflies are generalist predators in aquatic and associated terrestrial ecosystems [27], they consume a wide variety of insects and therefore harbor diverse gut microbial communities. Studies have investigated insect gut microbial communities to determine the prevalence of different microbes, their potential roles and their impact on host ecology and evolution [23]. Our results showed a large diversity of microorganisms displaying complex interrelationships in the dragonfly gut; the host species had a major impact on gut community richness. We observed substantial variation in the relative abundance of OTUs per species, which varied from 26 to 86 (Table 1). Similar patterns were also observed in three sympatric species of tsetse fly from Uganda [35]. In general, larger host species tend to harbor richer gut bacterial communities [23]. The richness of gut bacteria is associated with the habitat, ecological niche and predation ability of the host.

Pantala flavescens is a generalist species and consumes a diverse diet with excellent mobility; therefore P. flavescens had the largest OTU numbers [36-37]. C. dyeri had the smallest body but had the second largest number of OTUs, which may be related to its habitat. C. dyeri and B. contaminate shared similar habitats near water and preyed on small insects. O. sabino appeared to have lower OTU numbers when compared to C. dyeri and B. contaminate (Table 1), which may have been due to dietary specialization. Previous work has suggested that some dragonflies specialize on butterflies [38,39]. Recent analyses of sympatric dragonfly species have shown niche partitioning, with these dragonflies feeding on distinct species [40,41]. This dietary diversity may be associated with diverse gut microbial communities; however reports on dragonfly diets are rare. Nair and Agashe (2016) reported that OTU richness was strongly influenced by host species, the sampling month and interactions between the host sexes.

In our paper, dominant bacteria were similar in dragonfly gut bacterial communities. Proteobacteria and Firmicutes dominated and accounted for more than 97% in the gut community of dragonflies, which was also reported previously [23,42]. Shared genera included Serratia, Raoultella, Providencia, Pantoea, Lactococcus, Enterococcus, Enterobacter and Enterobacteriaceae_ unclassified. These shared genera may be related to basic functions of the host. Approximately 11 of 115 OTUs (10%) were shared across the four species. In contrast, a large portion of OTUs (approximately 56, 49% of the total) were rare and were found in single dragonfly species, e.g. Clostridium, Bacillus, Weissella, Chroococcidiopsis, Flavonifractor, Brochothrix. The existence of these exclusive genera may indicate specific functions within the host.

Hierarchical clustering, generated by gut communities, showed that evolutionary close dragonfly species had similar intestinal community compositions. These associations may result from facilitative interactions between bacteria from different genera, or they may indicate a common dietary (or environmental) source [23]. Data from un-weighted UniFrac distance PcoA and nonmetric multidimensional scaling also indicated similar associations.

In addition to interacting with the host, some bacterial species, isolated from damselfly feces, are perceived as disease causative agents, i.e. they responsible for urinary tract infections, pneumonia and septicemia in compromised hosts [43]. The fecal material of the damselfly can be used to monitor domestic antibiotic-resistant bacterial pollution associated with human health [43]. A metabolic disease of Libellula pulchella, caused by protozoan intestinal parasites, can result in the decline of mass specific fight muscle performance [44].

In summary, our results showed great diversity in gut microbiota from four dragonfly species. These gut microbiotas were highly connected, revealing complex interrelationship patterns. Gut community richness is often influenced by the host species; however functional mechanisms underlying gut microbiota diversity are poorly understood and require further research.

Acknowledgements

This research was supported by the National Natural Science Funds (No. 31960558) and the programs (GS201602 and 201622). We thank International Science Editing (http://www. International science editing.com) for editing this manuscript.

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Citation

Cao L, Bu X (2020) The Composition and Interaction of the Gut Microbiota in Four Species of Wild Dragonflies. Ann Appl Microbiol Biotech nol J 4: 7. doi: https://dx.doi.org/10.36876/apmbj607280

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Mycoplasma leachii Causes Bovine Mastitis: Evidence from Clinical Symptoms, Histopathology and Immunohistochemistry

Twelve quarters of six lactating cows were inoculated with Mycoplasma leachii strain GN407 through intramammary ductal infusion, and another twelve quarters were inoculated with Mycoplasma culture medium as controls. One lactating cow was used as negative control, in which two quarters were inoculated with Mycoplasma culture medium, and another two quarters were not inoculated with any medium. Clinical observations, histopathology and Immunohistochemistry (IHC) detection were performed on Post Inoculation Days (PIDs) 3, 6 and 9 to elucidate the pathogenicity of M. leachii in bovine mastitis. From PIDs 3 to 9, twelve inoculated quarters developed mild to severe clinical mastitis and mammary tissue histopathological changes, including inflammatory cell infiltration and architectural destruction of mammary gland ducts; on PID 9, the control quarters also developed mild mastitis and histopathological changes. Throughout the experimental period, the quarters of the negative control cow were clinically and pathologically normal. The M. leachii antigen was detected by IHC in the mammary tissues of the inoculated quarters as a weak signal on PID 6 and as a strong signal on PID 9; on PID 9, the M. leachii IHC signal was also detected in mammary gland epithelial cells of the control quarters of the inoculated cattle. The M. leachii antigen was not detected in the mammary tissues from the quarters of the negative control cow on PID 9. In conclusion, direct histological and immunohistochemical evidence confirmed that M. leachii causes clinical bovine mastitis through histopathological lesions induced by the invasion of the pathogen into mammary gland cells and inflammatory cell infiltration

Jitao Chang1, Debin Yu2, Jianbin Liang2, Jia Chen2, Fang Wang1, Zhigang Jiang1,
Xijun He3, Rui Wu2* and Li Yu1*


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Phylogenetic and Biochemical Analysis of the Reishi Mushroom (Ganoderma lucidum) Populations from Altai

G. lucidum is a typical representative of wood-rotting polypores of the Ganodermataceae family (Basidiomycetes). In Russia, G. lucidum is predominantly found in southern regions: in Stavropol and Krasnodar krais, Northern Caucasus, as well as in Altai taiga in logging areas. In this study we investigated the phylogeny of G. lucidum specimens from Altai based on the ITS1 ribosomal spacer, and compared them to reishi from other regions of the world. We also studied the phytochemical content of reishi fruit bodies. Results of the screening suggest that ethanol fractions contain mostly flavonoids, phenols, and coumarins; water fractions are dominated by tannins, carbohydrates, and coumarins; and hexane and ethyl acetate extracts, by terpenoids. The main fatty acids were palmitic, oleic, linoleic, and linolenic acids. We found that fruit bodies of Altai G. lucidum contained 32.4 mg of phenols per 1 g of extract (in pyrocatechol equivalent), while flavonoids made up 11.1 mg per g (in quercetin equivalent). Polysaccharide content was 10.72% of the absolutely dry substance.

Slynko NM, Blinov AG, Babenko VN, Mihailova SV, Bannikova SV, Shekhovtsov
SV, Nechiporenko NN, Goryachkovskaya TN, Veprev SG and Peltek SE*


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A Study on Mineralisation of Poly cis 1,4 isoprene (NR) and Synthetic Rubber Gloves (SRG) by the Bacterial Consortium

Objective: The aim of the study wasto isolate bacterial consortium from the effluent contaminated site that is used in the mineralizing both natural rubber and synthetic rubber, to optimise the growth conditions for efficient mineralisation and to biochemically characterise and to use 16s RNA sequencing for identifying the bacterial strains.

Materials and Methods: Natural rubber mineralizing bacterial consortium was isolated from effluent contaminated soil. The mineralisation study was performed for five days at every 24 h interval. Optimization studies were performed with different parameters such as varying concentrations of latex, pH, carbon sources, nitrogen sources, mixed carbon and nitrogen source and different temperature. The bacterial consortium mineralizing nr latex was used to mineralize Synthetic Rubber Gloves (SRG) using the same medium for 40 days at every 5 days interval. Effect of pre-treatment was studied by pre-treating the SRG with acetone and exposing it to sunlight. Mineralisation of the Rubber was confirmed by spectrophotometric and Fourier Transform Infra-Red
(FTIR) studies.

Results: Isolated organism was identified as Enterobater cloacae, Microbacterium laevaniformans and Methylobacterium rhodesianum. Maximum mineralisation of (1.66x10-4) was shown on the 4th day of incubation. Conformation of NR degradation was done by FTIR analysis that shows the presence of aldehyde and ketone produced due to bacterial degradation. The parameters giving optimum results were concentration of latex -1%, pH- 8.5, carbon source- Xylose, nitrogen source - Ammonium Nitrate, temperature- 37°C. Maximum mineralisation of synthetic rubber was shown on the 20th day (1.3x10-4). Among the pre-treated and the untreated samples most prominent distortions were visible on the surface of the sunlight sample when visualized under
scanning electron microscopy.

Conclusion: From the present investigation, it can be concluded that the isolated bacterial consortium containing the strains Enterobater cloacae, Microbacterium laevaniformans and Methylobacterium rhodesianum were able to mineralize natural rubber as well as synthetic rubber. This could be applied in the removal of waste rubber products present in the environment.

Veenagayathri Krishnaswamy* and Nikita Ahongsangbam


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Application of Chitosan in the Control of Fungal Infections by Dermatophytes

Dermatophytes are a group of fungi that can invade keratinized tissues of humans and other animals and produce an infection called Dermatophytosis. As chitosan possesses antimicrobial activity, it can potentially be used to treat dermatophytic infections. The main objective of this work was therefore, to evaluate the antifungal activity of chitosan upon some dermatophytes, namely Microsporum canis and Trychophyton rubrum. In view of this, Minimum Inhibitory (MICs) and Minimum Fungicidal Concentrations (MFCs) of chitosans upon the fungi were determined. Moreover, in order to understand the effect of chitosan on fungal activity, hair was infected with these fungi in the presence and absence of chitosan and Scanning Electron Microscopy (SEM) images were obtained and analyzed. Lastly, keratin-azure was used as substrate to evaluate the effect of chitosan on keratin degradation by M. canis and T. rubrum. The results showed that chitosan possesses antifungal activity against T. rubrum and M. canis, presenting MICs and MFCs ranging from 1.1 to 2.2 mg/mL. The antifungal activity of chitosan is concentration dependent. The analysis of SEM images of hair infected with these dermatophytes revealed that chitosan seems to have a protective effect on the hair, reducing the extent of damage when compared to the control. Chitosan also displayed important activity in preventing proteases’ action and in preventing hair damage. Based on the obtained results, it’s possible to conclude that chitosan showed relevant antifungal activity against dermatophytes, which opens good prospects to the use of chitosan as an alternative for the conventional fungal treatments.

Ana I Lopes, Freni K Tavaria* and Manuela E Pintado


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Characterization of Endophyte Microbiome Diversity in Chia Plant (Salvia hispanica L.)

A total of 9347 fungal and bacterial endophytes were isolated from the roots, stem and leaves of chia plant. Roots harbored more number of fungal endophytes than either stem or leaves whereas stem supported more number of bacterial endophytes than either roots or leaves. The nutritious plant supported more of gram negative compared to gram positive bacterial endophytes. The most common bacteria isolated were Pseudomonas Bacillus, and Cocci. The fungal endophytes isolated from root, stem and leaves of the chia plant showed the presence of Penincillium, Aspergillus, Fusarium, and Macrophomina spps. Dominant fungal endophyte was Aspergillus spp. which was found in all the plant parts instigated. Roots of the plant possessed maximum nitrogen fixers followed by stem and leaves. A proportion of 55% for the bacterial endophytes isolated from the plant chia plant were able to fix nitrogen whereas 25% were able to solubilize phosphorous. The phosphate solubilization efficiency was found to be highest for the Aspergillus spp at 83%.

Jasira Jzar1 , Mary Simiyu2 , Joseph Mafurah2*, Joshua Ogendo2 and Anne Osano3


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Isolation and Screening of Novel Isolates of Bifidobacteria from Human Milk as Potential Probiotic with Antidiarrheal Activity

Aims:
The objectives of this research work were isolation of Bifidobacteria from the human milk and its Probiotic characterization such as low pH, bile and in-vitro antimicrobial activity against diarrhea causing pathogen.

Methodology and Results:
In this research work, 47 bifidobacterial isolates were isolated from the human milk of the 50 lactating women and identified by using phenotypic methods. The isolates were examined in-vitro for their tolerance to unfavorable condition at low pH of 2 and 4 and at different concentrations of bile 0.3%, 0.5% and 1%. Further the isolates were tested for the antimicrobial activities by using diarrhea causing indicator stains such as E. coli, Salmonella enterica and Shigella boydii. Antibiotic susceptibility test was performed for the isolates which showed zone of inhibition in antimicrobial testing. Based on the result of in-vitro Probiotic test, the best four isolates Dbs18, Smk9, Smk4 and Smk5 were selected for further evaluation of tolerance test of phenol (0.1%, 0.2%, 0.4%), NaCl (5%, 8%, 12%). Auto aggregation and hydrophobicity assay were also done for the four selected isolates. In in-vitro test of low pH, out of 47 isolates only 14 isolates were able to grow whereas in bile tolerance assay most of the isolates grew well at 0.3% bile concentration but variability of growth of isolates were observed at 0.5% and 1% bile. In antimicrobial assay, 15 isolates out of 47 isolates showed antimicrobial activity after ruling out the inhibitory activity of low pH. In NaCl and phenol tolerance test all the four selected isolates were able to survive the different concentration of phenol and NaCl. The percentage of hydrophobicity and auto aggregation was highest in Dbs18 followed by Smk9 among the four isolates.

Conclusion, significance and impact of study:
Among the four isolates Dbs18 and Smk9 showed good hydrophobicity and auto aggregation ability. These bifidobacterial isolates Dbs18 and Smk9 are found to possess desirable Probiotic properties and will be selected for the in-vivo test and molecular identification will be done for the selected isolates. These bifidobacterial strains may act as a potential candidate of novel Probiotic strain isolated from human milk for the treatment of bacterial gastrointestinal diarrhea.

Sangeeta Huidrom* and Narotam Sharma


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Improving Bioelectricity Generation of Microbial Fuel Cell (MFC) With Mediators Using Kitchen Waste as Substrate

The enhancement of bioelectricity generation in the Microbial Fuel Cell (MFC) necessitated the introduction of exogenous compound (s) (i.e. mediators). The effect of 1ml of various synthetic exogenous mediators including dyes and metallorganics such as Ethylene Diamine Tetra Acid [EDTA], potassium ferricyanide [K3 Fe(CN)6 ], methylene blue [MB], neutral red [NR] and potassium permanganate [KMnO4 ] was investigated in a 21day study during electricity generation in an MFC. The maximum Power Density (PD) obtained without the addition of any mediator was 84.58mW/m2, while those MFCs which utilized mediators recorded higher energy yield. The highest power density and percentage energy contribution of 924.79mW/m2 (993.39%) was obtained using K3 Fe(CN)6, while values obtained with EDTA [803.71mW/m2 (850.24%)]; MB [340.45mW/m2 (302.52%)] and KMnO4 [192.14mW/m2 (121.17%)] as mediators were appreciably higher. Further study on the use of these mediators showed inhibitory effects with the % reduction of microbial load in the following trend as MB (4.96%) < EDTA (6.13%) < NR (11.67%) < Ferricyanide (19.16%) < KMnO4 (21.89%) when compared to the control. Although the application of mediators improved energy production, minimum inhibitory concentration of the mediators should be ascertained to prevent the eradication of electrogens during electricity production.

Adebule AP*, Aderiye BI and Adebayo AA 


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Bacillus Cereus Bacterium: A Human Pathogen

Bacteria belonging to genus Bacillus are endospore-forming bacteria Gram-positive and aerobic that are distinguished by the rod-designed cell morphology. Besides, they are found in varied environments. Bacillus sp., is known to have an economic interest. In fact, various strains or species are employed in animal and human food manufacture. Among Bacillus sp., Bacillus cereus is particularly dangerous for humans. This bacterium is a source of food toxin and involves severe infections.

Karim Ennouri