The Open Microbiology Journal




ISSN: 1874-2858 ― Volume 14, 2020
RESEARCH ARTICLE

Antibacterial Activities of Culture-dependent Bacteria Isolated from Apis nigrocincta Gut



Christian A. Lombogia1, 2, Max Tulung1, Jimmy Posangi1, 3, Trina E. Tallei1, 4, *
1 Entomology Study Program, Postgraduate Program, Sam Ratulangi University, Manado, North Sulawesi, Indonesia
2 Nursing Study Program, Faculty of Nursing, De La Salle Catholic University, Manado, North Sulawesi Indonesia
3 Public Health Study Program, Faculty of Public Health, Sam Ratulangi University, Manado, North Sulawesi, Indonesia
4 Department of Biology, Faculty of Mathematics and Natural Sciences, Sam Ratulangi University, Manado, North Sulawesi, Indonesia

Abstract

Introduction:

Apis nigrocincta is a honeybee endemic to Mindanao island (the Philippines), Sangihe island (North Sulawesi, Indonesia) and Sulawesi mainland (Indonesia). The genus Apis is well known to have symbiont in their guts, which helps balance the microbiome in the gut and host health.

Objective:

The objective of this study was to determine whether the bacteria isolated from the gut of honeybee Apis nigrocincta produce metabolites with potential growth inhibition against Staphylococcus aureus and Escerichia coli, the bacteria which are important pathogens in humans and animals.

Methods:

Bacteria isolated from honeybee gut were cultured in MRSA and several isolates were purified for testing. The antibacterial activity test method used in this study was well diffusion agar. Pure isolates were grown on NB. The treatments given were heating and also neutralizing the supernatant from each isolate.

Results:

Five bacterial isolates were successfully isolated from honeybee gut and purified. The five isolates showed antibacterial activity against pathogenic bacterial strain indicators. The results of molecular identification showed that four of these isolates were Bacillus cereus and the other one was Staphylococcus arlettae. Neutralized supernatant showed strong activity on both indicator strains. The five isolates showed higher inhibition activity against S. aureus compared to E. coli.

Conclusion:

The finding of this research concluded that two bacterial strains, B. cereus and S. arlettae isolated from A. nigrocincta gut can be investigated further as agents which produce bioactive compounds that have potential as an antibacterial.

Keywords: Apis nigrocincta, Antimicrobial peptide, Gut, Honeybee, Organic acids, S. arlettae.


Article Information


Identifiers and Pagination:

Year: 2020
Volume: 14
First Page: 72
Last Page: 76
Publisher Id: TOMICROJ-14-72
DOI: 10.2174/1874285802014010072

Article History:

Received Date: 03/01/2020
Revision Received Date: 24/02/2020
Acceptance Date: 06/03/2020
Electronic publication date: 23/04/2020
Collection year: 2020

© 2020 Lombogia et al.

open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International Public License (CC-BY 4.0), a copy of which is available at: (https://creativecommons.org/licenses/by/4.0/legalcode). This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.


* Address correspondence to this author at the Department of Biology, Faculty of Mathematics and Natural Sciences, Sam Ratulangi University, Manado, North Sulawesi, Indonesia, E-mail: trina_tallei@unsrat.ac.id





1. INTRODUCTION

Honeybee (genus: Apis) is a social insect rich in benefits. Everything produced by honeybees is known to have health benefits. One of the Apis species is A. nigrocincta, which is endemic to Mindanao island (the Philippines), Sangihe island (North Sulawesi, Indonesia) and Sulawesi mainland (Indonesia). This species is a medium-sized generalist and lodged in cavities such as caves and holes in the trunk [1Palmer K, Oldroyd B, Franck P, Hadisoesilo S. Very high paternity frequency in Apis nigrocincta. Insectes Soc 2001; 48: 327-32.
[http://dx.doi.org/10.1007/PL00001785]
, 2Hadisoesilo S. The diversity of indigenous honey bee species of Indonesia. Biodiversitas (Surak) 2001; 2(1): 123-8.
[http://dx.doi.org/10.13057/biodiv/d020107]
]. They live in groups and rarely move from one place to another.

Like other insects, honeybees have symbiotic and pathogenic interactions with microbes in their digestive tracts [3Corby-Harris V, Maes P, Anderson KE. The bacterial communities associated with honey bee (Apis mellifera) foragers. PLoS One 2014; 9(4)e95056
[http://dx.doi.org/10.1371/journal.pone.0095056] [PMID: 24740297]
, 4Engel P, Kwong WK, McFrederick Q, et al. The bee microbiome:impact on bee health and model for evolution and ecology of host-microbeinteractions. MBio 2016; 7(2): e02164-15.
[http://dx.doi.org/10.1128/mBio.02164-15] [PMID: 27118586]
], which are assumed to be influenced by the environment where they find food. The adult intestine of this insect is divided into four main organs (crop, midgut, ileum, and rectum), which provide different functions in catabolism and absorption of food and also different environments for symbiotic bacteria [5Chapman RF. The Insects: Structure and Function 4th ed. 1998.
[http://dx.doi.org/10.1017/CBO9780511818202]
]. Honeybee intestinal microbiota are distributed throughout the digestive tract, where midgut holds about 1-4% and ileum/rectum more than 90% of the most dominant bacteria found in honeybees [6Martinson VG, Moy J, Moran NA. Establishment of characteristic gut bacteria during development of the honeybee worker. Appl Environ Microbiol 2012; 78(8): 2830-40.
[http://dx.doi.org/10.1128/AEM.07810-11] [PMID: 22307297]
]. In addition, this intestinal symbiont has been shown to influence insect feeding behavior [7Akami M, Andongma AA, Zhengzhong C, et al. Intestinal bacteria modulate the foraging behavior of the oriental fruit fly Bactrocera dorsalis (Diptera: Tephritidae). PLoS One 2019; 14(1)e0210109
[http://dx.doi.org/10.1371/journal.pone.0210109] [PMID: 30650116]
].

Honeybee microbiota have been investigated to play a role in balancing host nutrition, weight gain, endocrine signaling, immune function, and pathogenic resistance, while microbiota disruption can lead to reduce host fitness [8Zheng H, Steele MI, Leonard SP, Motta EVS, Moran NA. Honey bees as models for gut microbiota research. Lab Anim (NY) 2018; 47(11): 317-25.
[http://dx.doi.org/10.1038/s41684-018-0173-x] [PMID: 30353179]
], most likely because they express antimicrobial peptides [9Kwong WK, Mancenido AL, Moran NA. Immune system stimulation by the native gut microbiota of honey bees. R Soc Open Sci 2017; 4(2)170003
[http://dx.doi.org/10.1098/rsos.170003] [PMID: 28386455]
] and organic acids such as lactic acid and acetic acid, which are produced by lactic acid bacteria and acetic acid bacteria [10Hamdi C, Balloi A, Essanaa J, Crotti E, Gonella E, Raddadi N, et al. Cherif Gut microbiome dysbiosis and honeybee health. J Appl Entomol 2011; 135: 524-53.
[http://dx.doi.org/10.1111/j.1439-0418.2010.01609.x]
].

Most research on microbiomes in the intestine of honeybees have emphasized the lactic acid bacteria, which are known to have antimicrobial activity [11Janashia I, Choiset Y, Robesona H, et al. Protection of honeybee Apis mellifera by its endogenous and exogenous lactic flora against bacterial infections. Ann Agric Sci 2016; 14(3): 177-81., 12Niode J, Salaki CL, Rumokoy LJM, Tallei TE. Lactic acid bacteria from digestive tract of honeybee and their potential as probiotics 2019. Unpublished]. In this study, successfully cultured bacteria were used as isolates to observe their ability to produce antimicrobial activity against S. aureus and E. coli.

2. METHODS

2.1. Isolation and Purification of Bacteria from Honeybee Gut

The honeybees were surface sterilized by following the procedure from Lombogia et al. [13Lombogia CA, Tulung M, Posangi J, Tallei TE. Bacterial composition, community structure, and diversity in Apis nigrocincta gut 2019. Unpublished]. The gut was removed aseptically and placed on a petri dish, cut into small pieces, then put into Eppendorf tube containing 0.9% sterile NaCl, then crushed using micropestel. The tube was centrifuged at 6000 rpm to precipitate intestinal debris. One hundred microliters of the supernatant were taken and spread on de Man, Rogosa and Sharpe Agar (MRSA) supplemented with CaCO3, then incubated for 2x24 hours at 37°C. The large colonies that appeared different were separated and purified. The bacteria were then stored on Nutrient Agar (NA) slant for subsequent use.

2.2. Antibacterial Activity Test against Indicator Pathogenic Strains

Two pathogenic strains, S. aureus and E. coli, were used as indicator bacteria to determine the ability of antimicrobial activity of bacteria isolated from honeybee gut. The procedure for the antibacterial test was carried out by following Tallei et al. [14Tallei TE. Potential next-generation probiotics isolated from Romaine lettuce (Lactuca sativa var. longifolia Lam.) fermented brine. Submitted to 10th International Seminar of Indonesian Society for Microbiology (10th ISISM) & 12th Congress of Indonesian Society for Microbiology (12th CISM), Surakarta Indonesia. 2019.2019., 15Yelnetty A. Indigenous lactic acid bacteria isolated from spontaneous fermented goat milk as potential probiotics. Unpublished 2019.] with modification. Pure bacterial isolates were grown on Nutrient Broth (NB) for 24 hours at 37°C in an Eppendorf tube. Isolates that grew were killed at 80°C for 2 hours and centrifuged at 10,000 rpm for 10 minutes to prepare cell-free culture supernatants (CFSs) and to inactivate antimicrobial peptides that might present in the supernatant. In addition, other supernatants that were not heated were neutralized using NaOH to reach pH 6.0. This was intended to neutralize organic acids and to predict the antimicrobial peptides that were likely produced by isolates.

Indicator bacteria were grown respectively on NB for 24 hours at 37°C then poured on each NA medium, which had wells with a diameter of 5 mm. The media were then incubated for 2 hours at 37°C. One hundred microliters of each CFFs were poured into wells. Likewise, the supernatant that had been neutralized from each isolate was poured as much as 100 µl into other empty wells. The NA media were then incubated at 37°C for 48 hours. The diameter of the inhibition zone produced was measured, which was indicated by the presence of a clear zone in the vicinity of the well. Five µg/ml of antibiotics (1-cyclopropyl-6-fluoro-1,4-dihydro-4-oxo-7-(1-piperazinyl)-3-quinolinecarboxylic) was used as positive control and sterile dH20 as negative control.

2.3. Molecular Identification of Bacterial Isolates

Purified bacterial isolates that exhibited antibacterial activities were identified molecularly using the 16S rRNA marker gene following the procedure carried out by Tallei et al. [14Tallei TE. Potential next-generation probiotics isolated from Romaine lettuce (Lactuca sativa var. longifolia Lam.) fermented brine. Submitted to 10th International Seminar of Indonesian Society for Microbiology (10th ISISM) & 12th Congress of Indonesian Society for Microbiology (12th CISM), Surakarta Indonesia. 2019.2019.]. The 16S rRNA sequences from each bacterial isolate were searched for similarities in the Ez-Taxon database portal (https://www.ezbiocloud.net/) [16Yoon SH, Ha SM, Kwon S, et al. Introducing EzBioCloud: a taxonomically united database of 16S rRNA gene sequences and whole-genome assemblies. Int J Syst Evol Microbiol 2017; 67(5): 1613-7.
[http://dx.doi.org/10.1099/ijsem.0.001755] [PMID: 28005526]
].

3. RESULTS

The antibacterial activities of bacteria isolated from honeybee gut were tested against pathogenic bacteria S. aureus and E. coli. The antibacterial test results from the supernatant of each isolate that was heated for 2 hours at 80°C (treatment 1) against bacterial indicators are presented in Table 1. Table 2 shows the antibacterial test of the supernatant of each isolate, which was neutralized to pH 6 (treatment 2). The classification of inhibition according to Zare Mirzaei et al. [17Zare Mirzaei E, Lashani E, Davoodabadi A. Antimicrobial properties of lactic acid bacteria isolated from traditional yogurt and milk against Shigella strains. GMS Hyg Infect Control 2018; 13: Doc01.
[PMID: 29416958]
] is as follows: <11 mm (negative -), 11-16 mm (mild +), 17–22 mm (strong ++), and >23 mm (very strong +++). In treatments 1 and 2, it can be seen that the five isolates had higher inhibitory activities against S. aureus than E. coli. Treatment 2 appeared to have a higher activity than treatment 1, both for S. aureus and E. coli. In treatment 1, isolate Lp.ov showed the highest activity against both indicator strains. In treatment 2, isolate L.pt.2 showed the highest inhibitory activity against S. aureus and Lp.ov showed the highest inhibitory activity against E. coli.

As all isolates showed antibacterial activity, all were identified using molecular markers of the 16S rRNA gene. The results of searching for the appropriate sequences performed on the Ez-Taxon database platform are shown in Table 3. Isolates Lo.Pt 1, L.pt.2, L.10, and L.10.pt were identified as Bacillus cereus, while isolate Lp.ov was identified as S. arlettae. Of all treatments, B. cereus strain Lo.Pt 1, L.pt.2, and L.10 showed very strong activity in treatment 2 against S. aureus, and their inhibitory activities exceeded control antibiotics. It is suspected that B. cereus has a high AMP content.

4. DISCUSSION

The present study showed that there were five isolates that exhibited antibacterial activity against pathogenic strains S. aureus and E. coli. All isolates were identified molecularly, and 4 of them (Lo.Pt 1, L.pt.2, L.10, and L.10.pt) were identified as B. cereus, while Lp.ov was identified as S. arlettae.

Table 1
The antibacterial test of the supernatant heated at 80°C for 2 hours (treatment 1).


Table 2
The antibacterial test of supernatant which has been neutralized up to pH 6 (treatment 2).


Table 3
Results of identification of bacterial isolates using the 16S rRNA gene.


The supernatant in treatment 1 was heated, so it is assumed that if there is Antimicrobial Peptide (AMP), it will become inactive so that bioactive compounds that may have a role in inhibition include organic acids such lactic acid, acetate acid, and formic acid, benzoic acid, as well as hydrogen peroxide (H2O2) and alcohol. As reported by Adam and Hall [18Adams MR, Hall CJ. Growth inhibition of food-borne pathogens by lactic and acetic acids and their mixtures. Int J Food Sci Technol 1988; 23: 287-92.
[http://dx.doi.org/10.1111/j.1365-2621.1988.tb00581.x]
], organic acids reduced the pH of the media and inhibited the growth of pathogenic organisms. The supernatant in treatment 2 was neutralized so that the pH reached 6, assuming if there are organic acids, it will be neutralized, so that bioactive compounds such as AMPs and fatty acids play a role in antibacterial activity.

Baindara et al. [19Baindara P, Mandal SM, Chawla N, Singh PK, Pinnaka AK, Korpole S. Characterization of two antimicrobial peptides produced by a halotolerant Bacillus subtilis strain SK.DU.4 isolated from a rhizosphere soil sample. AMB Express 2013; 3(1): 2.
[http://dx.doi.org/10.1186/2191-0855-3-2] [PMID: 23289832]
] reported that halotolerant B. cereus isolated from a rhizosphere soil sample produced two AMPs that were active against Gram-positive bacteria. Some AMPs produced by Bacillus sp. include broad-spectrum bacteriocin, which has a bactericidal or bacteriostatic effect [20Salazar-Marroquín EL, Galán-Wong LJ, Moreno-Medina VR, Reyes-López MÁ, Pereyra-Alférez B. Bacteriocins synthesized by Bacillus thuringiensis: generalities and potential applications. Rev Med Microbiol 2016; 27(3): 95-101.
[http://dx.doi.org/10.1097/MRM.0000000000000076] [PMID: 27340340]
-22Ramachandran R, Chalasani AG, La R, Roy U. A Broad-spectrum antimicrobial activity of Bacillus subtilis RLID 12.1.Sci World J 2014; 968487:10pp.], surface-active biosurfactants like lipopeptides, glycopeptides and nonribosomally synthesized cyclic peptides [23Mukherjee S, Das P, Sen R. Towards commercial production of microbial surfactants. Trends Biotechnol 2006; 24(11): 509-15.
[http://dx.doi.org/10.1016/j.tibtech.2006.09.005] [PMID: 16997405]
, 24Rodrigues L, Banat IM, Teixeira J, Oliveira R. Biosurfactants: potential applications in medicine. J Antimicrob Chemother 2006; 57(4): 609-18.
[http://dx.doi.org/10.1093/jac/dkl024] [PMID: 16469849]
], and Caseicin A and B [25Kent RM, Guinane CM, O’Connor PM, et al. Production of the antimicrobial peptides Caseicin A and B by Bacillus isolates growing on sodium caseinate. Lett Appl Microbiol 2012; 55(2): 141-8.
[http://dx.doi.org/10.1111/j.1472-765X.2012.03271.x] [PMID: 22642665]
].

The Bacillus group is the dominant bacterium in the honey bee gut [26Wang M, Zhao WZ, Xu H, Wang ZW, He SY. Bacillus in the guts of honey bees (Apis mellifera; Hymenoptera: Apidae) mediate changes in amylase values. Eur J Entomol 2015; 112: 619-24.
[http://dx.doi.org/10.14411/eje.2015.095]
] and 67% of the bacteria isolated from honey are the Bacillus group [27Wen Y, Wang L, Jin Y, et al. The microbial community dynamics during the vitex honey ripening process in the honeycomb. Front Microbiol 2017; 8: 1649.
[http://dx.doi.org/10.3389/fmicb.2017.01649] [PMID: 28912763]
]. Most intestinal bacteria of A. mellifera in the North-west region of Pakistan belong to the genus Staphylococcus and Bacillus, which are tolerant of the acidic environment caused by fermented sugars. These bacteria are thought to be beneficial microbes that are involved in maintaining the health of honey bees. Staphylococcus was estimated to reach 29% of the total intestinal microbial samples analyzed [28Anjum SI, Shah AH, Aurongzeb M, et al. Characterization of gut bacterial flora of Apis mellifera from north-west Pakistan. Saudi J Biol Sci 2018; 25(2): 388-92.
[http://dx.doi.org/10.1016/j.sjbs.2017.05.008] [PMID: 29472796]
]. In this current study, S. arlettae showed strong inhibition against S. aureus for treatment 1 or 2. Staphylococcal strains are rarely discussed in the literature available in relation to microbiota bee gut [28Anjum SI, Shah AH, Aurongzeb M, et al. Characterization of gut bacterial flora of Apis mellifera from north-west Pakistan. Saudi J Biol Sci 2018; 25(2): 388-92.
[http://dx.doi.org/10.1016/j.sjbs.2017.05.008] [PMID: 29472796]
]. On another occasion, Wu et al. [29Wu M, Sugimura y, Iwata K, et al. Inhibitory effect of gut cacteria from the Japanese honey bee, Apis cerana japonica, against Melissococcus plutonius, the causal agent of European foulbrood disease. J Insect Sci 2014; 14(129): 1-13.
[http://dx.doi.org/10.1093/jis/14.1.129]
] stated that most culture-dependent gut bacteria from Japanese honey bee belonged to genera Bacillus, Staphylococcus, and Pantoea. Gabriel [30Gabriel BJ. Gut Symbiont Viability in Honey Bees Exposed to Agrochemical Stressors Dissertations and Student Research in Entomology University of Nebraska – Lincoln 2018.] reported that symbiont gut in honey bees that were exposed to agrochemical stresses constitutes 10% of Staphylococcus from the total population. Although showing antimicrobial activity against indicator bacteria, their effectiveness varies from strain to strain. This may be because even though the species is the same, the number of metabolites produced also varies depending on the strain.

Understanding the symbiotic relationship between honey bees and their bacterial community can inspire ideas about how to exploit these microflorae to protect the health of the host [11Janashia I, Choiset Y, Robesona H, et al. Protection of honeybee Apis mellifera by its endogenous and exogenous lactic flora against bacterial infections. Ann Agric Sci 2016; 14(3): 177-81.]. The bacteria that produce dominant metabolites and are available in the digestive tracts of insects, can balance the natural conditions.

CONCLUSION

The results concluded that culture-dependent bacteria that had been successfully isolated from the intestines of A. nigrocincta were B. cereus and S. arlettae. Both of these bacterial strains had strong antibacterial activity against the indicator bacteria S. aureus and E. coli. Both strains are more potent against S. aureus as compared to E. coli.

ETHICS APPROVAL AND CONSENT TO PARTICIPATE

Not applicable.

HUMAN AND ANIMAL RIGHTS

No animals/humans were used for studies that are the basis of this research.

CONSENT FOR PUBLICATION

Not applicable.

AVAILABILITY OF DATA AND MATERIALS

The data that support the findings of this study are available from the corresponding author, [TET], upon reasonable request.

FUNDING

None.

CONFLICTS OF INTEREST

The author declares no conflict of interest, financial or otherwise.

ACKNOWLEDGEMENTS

The authors wish to thank the Postgraduate Program and Department of Biology, Faculty of Mathematics, and Natural Sciences, Universitas Sam Ratulangi, for providing places to conduct the research.

REFERENCES

[1] Palmer K, Oldroyd B, Franck P, Hadisoesilo S. Very high paternity frequency in Apis nigrocincta. Insectes Soc 2001; 48: 327-32.
[http://dx.doi.org/10.1007/PL00001785]
[2] Hadisoesilo S. The diversity of indigenous honey bee species of Indonesia. Biodiversitas (Surak) 2001; 2(1): 123-8.
[http://dx.doi.org/10.13057/biodiv/d020107]
[3] Corby-Harris V, Maes P, Anderson KE. The bacterial communities associated with honey bee (Apis mellifera) foragers. PLoS One 2014; 9(4)e95056
[http://dx.doi.org/10.1371/journal.pone.0095056] [PMID: 24740297]
[4] Engel P, Kwong WK, McFrederick Q, et al. The bee microbiome:impact on bee health and model for evolution and ecology of host-microbeinteractions. MBio 2016; 7(2): e02164-15.
[http://dx.doi.org/10.1128/mBio.02164-15] [PMID: 27118586]
[5] Chapman RF. The Insects: Structure and Function 4th ed. 1998.
[http://dx.doi.org/10.1017/CBO9780511818202]
[6] Martinson VG, Moy J, Moran NA. Establishment of characteristic gut bacteria during development of the honeybee worker. Appl Environ Microbiol 2012; 78(8): 2830-40.
[http://dx.doi.org/10.1128/AEM.07810-11] [PMID: 22307297]
[7] Akami M, Andongma AA, Zhengzhong C, et al. Intestinal bacteria modulate the foraging behavior of the oriental fruit fly Bactrocera dorsalis (Diptera: Tephritidae). PLoS One 2019; 14(1)e0210109
[http://dx.doi.org/10.1371/journal.pone.0210109] [PMID: 30650116]
[8] Zheng H, Steele MI, Leonard SP, Motta EVS, Moran NA. Honey bees as models for gut microbiota research. Lab Anim (NY) 2018; 47(11): 317-25.
[http://dx.doi.org/10.1038/s41684-018-0173-x] [PMID: 30353179]
[9] Kwong WK, Mancenido AL, Moran NA. Immune system stimulation by the native gut microbiota of honey bees. R Soc Open Sci 2017; 4(2)170003
[http://dx.doi.org/10.1098/rsos.170003] [PMID: 28386455]
[10] Hamdi C, Balloi A, Essanaa J, Crotti E, Gonella E, Raddadi N, et al. Cherif Gut microbiome dysbiosis and honeybee health. J Appl Entomol 2011; 135: 524-53.
[http://dx.doi.org/10.1111/j.1439-0418.2010.01609.x]
[11] Janashia I, Choiset Y, Robesona H, et al. Protection of honeybee Apis mellifera by its endogenous and exogenous lactic flora against bacterial infections. Ann Agric Sci 2016; 14(3): 177-81.
[12] Niode J, Salaki CL, Rumokoy LJM, Tallei TE. Lactic acid bacteria from digestive tract of honeybee and their potential as probiotics 2019. Unpublished
[13] Lombogia CA, Tulung M, Posangi J, Tallei TE. Bacterial composition, community structure, and diversity in Apis nigrocincta gut 2019. Unpublished
[14] Tallei TE. Potential next-generation probiotics isolated from Romaine lettuce (Lactuca sativa var. longifolia Lam.) fermented brine. Submitted to 10th International Seminar of Indonesian Society for Microbiology (10th ISISM) & 12th Congress of Indonesian Society for Microbiology (12th CISM), Surakarta Indonesia. 2019.2019.
[15] Yelnetty A. Indigenous lactic acid bacteria isolated from spontaneous fermented goat milk as potential probiotics. Unpublished 2019.
[16] Yoon SH, Ha SM, Kwon S, et al. Introducing EzBioCloud: a taxonomically united database of 16S rRNA gene sequences and whole-genome assemblies. Int J Syst Evol Microbiol 2017; 67(5): 1613-7.
[http://dx.doi.org/10.1099/ijsem.0.001755] [PMID: 28005526]
[17] Zare Mirzaei E, Lashani E, Davoodabadi A. Antimicrobial properties of lactic acid bacteria isolated from traditional yogurt and milk against Shigella strains. GMS Hyg Infect Control 2018; 13: Doc01.
[PMID: 29416958]
[18] Adams MR, Hall CJ. Growth inhibition of food-borne pathogens by lactic and acetic acids and their mixtures. Int J Food Sci Technol 1988; 23: 287-92.
[http://dx.doi.org/10.1111/j.1365-2621.1988.tb00581.x]
[19] Baindara P, Mandal SM, Chawla N, Singh PK, Pinnaka AK, Korpole S. Characterization of two antimicrobial peptides produced by a halotolerant Bacillus subtilis strain SK.DU.4 isolated from a rhizosphere soil sample. AMB Express 2013; 3(1): 2.
[http://dx.doi.org/10.1186/2191-0855-3-2] [PMID: 23289832]
[20] Salazar-Marroquín EL, Galán-Wong LJ, Moreno-Medina VR, Reyes-López MÁ, Pereyra-Alférez B. Bacteriocins synthesized by Bacillus thuringiensis: generalities and potential applications. Rev Med Microbiol 2016; 27(3): 95-101.
[http://dx.doi.org/10.1097/MRM.0000000000000076] [PMID: 27340340]
[21] Sumi CD, Yang BW, Yeo I-C, Hahm YT. Antimicrobial peptides of the genus Bacillus: a new era for antibiotics. Can J Microbiol 2015; 61(2): 93-103.
[http://dx.doi.org/10.1139/cjm-2014-0613] [PMID: 25629960]
[22] Ramachandran R, Chalasani AG, La R, Roy U. A Broad-spectrum antimicrobial activity of Bacillus subtilis RLID 12.1.Sci World J 2014; 968487:10pp.
[23] Mukherjee S, Das P, Sen R. Towards commercial production of microbial surfactants. Trends Biotechnol 2006; 24(11): 509-15.
[http://dx.doi.org/10.1016/j.tibtech.2006.09.005] [PMID: 16997405]
[24] Rodrigues L, Banat IM, Teixeira J, Oliveira R. Biosurfactants: potential applications in medicine. J Antimicrob Chemother 2006; 57(4): 609-18.
[http://dx.doi.org/10.1093/jac/dkl024] [PMID: 16469849]
[25] Kent RM, Guinane CM, O’Connor PM, et al. Production of the antimicrobial peptides Caseicin A and B by Bacillus isolates growing on sodium caseinate. Lett Appl Microbiol 2012; 55(2): 141-8.
[http://dx.doi.org/10.1111/j.1472-765X.2012.03271.x] [PMID: 22642665]
[26] Wang M, Zhao WZ, Xu H, Wang ZW, He SY. Bacillus in the guts of honey bees (Apis mellifera; Hymenoptera: Apidae) mediate changes in amylase values. Eur J Entomol 2015; 112: 619-24.
[http://dx.doi.org/10.14411/eje.2015.095]
[27] Wen Y, Wang L, Jin Y, et al. The microbial community dynamics during the vitex honey ripening process in the honeycomb. Front Microbiol 2017; 8: 1649.
[http://dx.doi.org/10.3389/fmicb.2017.01649] [PMID: 28912763]
[28] Anjum SI, Shah AH, Aurongzeb M, et al. Characterization of gut bacterial flora of Apis mellifera from north-west Pakistan. Saudi J Biol Sci 2018; 25(2): 388-92.
[http://dx.doi.org/10.1016/j.sjbs.2017.05.008] [PMID: 29472796]
[29] Wu M, Sugimura y, Iwata K, et al. Inhibitory effect of gut cacteria from the Japanese honey bee, Apis cerana japonica, against Melissococcus plutonius, the causal agent of European foulbrood disease. J Insect Sci 2014; 14(129): 1-13.
[http://dx.doi.org/10.1093/jis/14.1.129]
[30] Gabriel BJ. Gut Symbiont Viability in Honey Bees Exposed to Agrochemical Stressors Dissertations and Student Research in Entomology University of Nebraska – Lincoln 2018.
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"Open access journals are a novel concept in the medical literature. They offer accessible information to a wide variety of individuals, including physicians, medical students, clinical investigators, and the general public. They are an outstanding source of medical and scientific information."


Jeffrey M. Weinberg
(St. Luke's-Roosevelt Hospital Center, USA)

"Open access journals are extremely useful for graduate students, investigators and all other interested persons to read important scientific articles and subscribe scientific journals. Indeed, the research articles span a wide range of area and of high quality. This is specially a must for researchers belonging to institutions with limited library facility and funding to subscribe scientific journals."


Debomoy K. Lahiri
(Indiana University School of Medicine, USA)

"Open access journals represent a major break-through in publishing. They provide easy access to the latest research on a wide variety of issues. Relevant and timely articles are made available in a fraction of the time taken by more conventional publishers. Articles are of uniformly high quality and written by the world's leading authorities."


Robert Looney
(Naval Postgraduate School, USA)

"Open access journals have transformed the way scientific data is published and disseminated: particularly, whilst ensuring a high quality standard and transparency in the editorial process, they have increased the access to the scientific literature by those researchers that have limited library support or that are working on small budgets."


Richard Reithinger
(Westat, USA)

"Not only do open access journals greatly improve the access to high quality information for scientists in the developing world, it also provides extra exposure for our papers."


J. Ferwerda
(University of Oxford, UK)

"Open Access 'Chemistry' Journals allow the dissemination of knowledge at your finger tips without paying for the scientific content."


Sean L. Kitson
(Almac Sciences, Northern Ireland)

"In principle, all scientific journals should have open access, as should be science itself. Open access journals are very helpful for students, researchers and the general public including people from institutions which do not have library or cannot afford to subscribe scientific journals. The articles are high standard and cover a wide area."


Hubert Wolterbeek
(Delft University of Technology, The Netherlands)

"The widest possible diffusion of information is critical for the advancement of science. In this perspective, open access journals are instrumental in fostering researches and achievements."


Alessandro Laviano
(Sapienza - University of Rome, Italy)

"Open access journals are very useful for all scientists as they can have quick information in the different fields of science."


Philippe Hernigou
(Paris University, France)

"There are many scientists who can not afford the rather expensive subscriptions to scientific journals. Open access journals offer a good alternative for free access to good quality scientific information."


Fidel Toldrá
(Instituto de Agroquimica y Tecnologia de Alimentos, Spain)

"Open access journals have become a fundamental tool for students, researchers, patients and the general public. Many people from institutions which do not have library or cannot afford to subscribe scientific journals benefit of them on a daily basis. The articles are among the best and cover most scientific areas."


M. Bendandi
(University Clinic of Navarre, Spain)

"These journals provide researchers with a platform for rapid, open access scientific communication. The articles are of high quality and broad scope."


Peter Chiba
(University of Vienna, Austria)

"Open access journals are probably one of the most important contributions to promote and diffuse science worldwide."


Jaime Sampaio
(University of Trás-os-Montes e Alto Douro, Portugal)

"Open access journals make up a new and rather revolutionary way to scientific publication. This option opens several quite interesting possibilities to disseminate openly and freely new knowledge and even to facilitate interpersonal communication among scientists."


Eduardo A. Castro
(INIFTA, Argentina)

"Open access journals are freely available online throughout the world, for you to read, download, copy, distribute, and use. The articles published in the open access journals are high quality and cover a wide range of fields."


Kenji Hashimoto
(Chiba University, Japan)

"Open Access journals offer an innovative and efficient way of publication for academics and professionals in a wide range of disciplines. The papers published are of high quality after rigorous peer review and they are Indexed in: major international databases. I read Open Access journals to keep abreast of the recent development in my field of study."


Daniel Shek
(Chinese University of Hong Kong, Hong Kong)

"It is a modern trend for publishers to establish open access journals. Researchers, faculty members, and students will be greatly benefited by the new journals of Bentham Science Publishers Ltd. in this category."


Jih Ru Hwu
(National Central University, Taiwan)


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