Identification of Lactobacillus plantarum, Lactobacillus pentosus and Lactobacillus fermentum from honey stomach of honeybee

The effects of thymol, oxalic acid (Api-Bioxal) and hops extract (Nose-Go) on viability, the Nosema sp. spore load and the expression of vg and sod-1 genes in infected honey bees

This study was done to investigate the effects of thymol, fumagillin, oxalic acid (Api-Bioxal) and hops extract (Nose-Go) on Nosema sp. spore load, the expression of vitellogenin (vg) and superoxide-dismutase-1 (sod-1) genes and mortality of bees infected with N. ceranae. Five healthy colonies were assigned as the negative control, and 25 Nosema sp. infected colonies were assigned to five treatment groups including: the positive control: no additive to sirup; fumagillin 26.4 mg/L, thymol 0.1 g/L, Api-Bioxal 0.64 g/L and Nose-Go 5.0 g/L sirup. The reduction in the number of Nosema sp. spores in fumagillin, thymol, Api-Bioxal and Nose-Go compared to the positive control was 54, 25, 30 and 58%, respectively. Nosema sp. infection in all infected groups increased (p < .05) Escherichia coli population compared to the negative control. Nose-Go had a negative effect on lactobacillus population compared to other substances. Nosema sp. infection decreased vg and sod-1 genes expression in all infected groups compared to the negative control. Fumagillin and Nose-Go increased the expression of vg gene, and Nose-Go and thymol increased the expression of sod-1 gene than the positive control. Nose-Go has the potential to treat nosemosis if the necessary lactobacillus population is provided in the gut.

In Silico Probiogenomic Characterization of Lactobacillus delbrueckii subsp. lactis A4 Strain Isolated from an Armenian Honeybee Gut

A Lactobacillus delbrueckii ssp. lactis strain named A4, isolated from the gut of an Armenian honeybee, was subjected to a probiogenomic characterization because of its unusual origin. A whole-genome sequencing was performed, and the bioinformatic analysis of its genome revealed a reduction in the genome size and the number of the genes-a process typical for the adaptation to endosymbiotic conditions. Further analysis of the genome revealed that Lactobacillus delbrueckii ssp. lactis strain named A4 could play the role of a probiotic endosymbiont because of the presence of intact genetic sequences determining antioxidant properties, exopolysaccharides synthesis, adhesion properties, and biofilm formation, as well as an antagonistic activity against some pathogens which is not due to pH or bacteriocins production. Additionally, the genomic analysis revealed significant potential for stress tolerance, such as extreme pH, osmotic stress, and high temperature. To our knowledge, this is the first report of a potentially endosymbiotic Lactobacillus delbrueckii ssp. lactis strain adapted to and playing beneficial roles for its host.

Bee Pollen as Functional Food: Insights into Its Composition and Therapeutic Properties

Bee pollen is a hive product made up of flower pollen grains, nectar, and bee salivary secretions that beekeepers can collect without damaging the hive. Bee pollen, also called bee-collected pollen, contains a wide range of nutritious elements, including proteins, carbs, lipids, and dietary fibers, as well as bioactive micronutrients including vitamins, minerals, phenolic, and volatile compounds. Because of this composition of high quality, this product has been gaining prominence as a functional food, and studies have been conducted to show and establish its therapeutic potential for medical and food applications. In this context, this work aimed to provide a meticulous summary of the most relevant data about bee pollen, its composition—especially the phenolic compounds—and its biological and/or therapeutic properties as well as the involved molecular pathways.

Anti-inflammatory and Immunostimulant Therapy with Lactobacillus fermentum and Lactobacillus plantarum in COVID-19: A Literature Review

Inflammatory diseases are diseases characterized by inflammatory symptoms. Acute inflammatory disease can cause dysregulation of the inflammatory immune response, thereby inhibiting the development of protective immunity against infection. Among the acute inflammatory disease is COVID-19. The initial viral infection causes the antigen-presenting cells to detect the virus through a phagocytosis mechanism in the form of macrophage and dendritic cells. Lactobacillus fermentum and L. plantarum are gram-positive bacteria potentially serving as immunomodulators caused by inflammation and immune system response. Short-chain fatty acids (SCFA) produced by Lactobacillus can induce immune response through tolerogenic dendritic cells. This probiotic bacterium can induce the production of different cytokines or chemokines. Following the results of in vitro and in vivo tests, L. fermentum and L. plantarum can induce IL-10 release to activate regulatory T-cell and inhibit tumor necrosis factor-α (TNF-α) binding activity of nuclear factor kappa B (NF-κB). Literature review showed that dysregulation of inflammatory immune response disorders due to inflammatory disease could be treated using probiotic bacteria L. fermentum and L. plantarum. Therefore, it is necessary to conduct further studies on the potential of indigenous Indonesian strains of these two bacteria as anti-inflammatory and immunostimulants.

Preliminary evaluation of probiotic properties and safety profile of Lactiplantibacillus plantarum isolated from spontaneously fermented milk, Amabere amaruranu

The aim of this study was to assess the probiotic potential and safety profile of a Lactiplantibacillus plantarum EGER41 strain isolated from Kenyan spontaneously fermented milk, Amabere amaruranu. The L. plantarum EGER41 isolate was tested for temperature sensitivity (at 15 °C, 30 °C, 37 °C, and 45 °C), pH tolerance (at 2.0, 2.5, 3.0, 3.5, and 6.5 as control), and 0.4% phenol tolerance to observe its survival in the gastrointestinal tract of humans. For safety evaluation of the isolate, antagonistic activity was tested against pathogenic strains of Staphylococcus aureus, Escherichia coli, Salmonella enterica serovar Typhi, and Candida albicans, while antibiotic susceptibility pattern was examined using nalidixic acid, ampicillin, azithromycin, ciprofloxacin, tetracycline, gentamicin, and chloramphenicol antibiotic discs and haemolytic activity was done using lamb blood agar. The L. plantarum isolate had an optimal growth at 37 °C, it also demonstrated low pH tolerance (2.0–3.5). It was able to maintain its viability (∼100%) after exposure to 0.4% phenol. The selected isolate showed inhibition (antagonistic activity) against the pathogens with S. typhi having the largest (ZDI = 31.0 ± 1.73 mm) zone of diameter inhibition (ZDI) and Candida albicans having the least (ZDI = 18.0 ± 0.76 mm). L. plantarum isolate was sensitive to Azithromycin, tetracycline and chloramphenicol and was intermediately sensitive to gentamycin, while it was resistant to nalidixic acid, ampicillin, and ciprofloxacin. The isolate also exhibited γ-haemolytic activity hence safe for use as a starter culture and was identified as a Lactiplantibacillus plantarum EGER 41 strain based on 16S rRNA gene sequencing. The selected isolate can potentially be used as a starter culture and a probiotic since it had excellent probiotic properties.

Screening and Molecular Identification of Lactic Acid Bacteria Producing β-Glucan in Boza and Cider

The goal of this study was screening and molecular identification of Lactic Acid Bacteria (LAB) producing β-glucan from different species isolated from boza and cider compared to a standard strain for Lactobacillus rhamnosus NRRL 1937 (LGG). From 48 unknown isolates, four LAB strains were selected. Based on the NCBI database, their nomenclature was A3, B6, and C9 for Limosilactobacillus fermentum SH1, SH2, and SH3 along with D6 for Leuconostoc mesenteroides SH4. Also, their similarity values were 100%, 99.8%, 100%, and 100%, respectively. The potential of Exopolysaccharide (EPS) (as β-glucan) production for selected LAB strains by gtf gene, conventional PCR and gene expression using both LGG as a control and LAB 16S rRNA gene as a house-keeping gene was investigated. In addition, EPS (mg/100 mL), cell mass (mg/100 mL), pH, total carbohydrate%, total protein% and β-glucan% by the HPLC for all selected LAB isolates were studied. All results of genetic and chemical tests proved the superiority of B6 treatment for L. fermentum SH2. The results showed the superiority of B6 treatment in gtf gene expression (14.7230 ± 0.070-fold) followed by C9 and A3 treatments, which were 10.1730 ± 0.231-fold and 8.6139 ± 0.320-fold, respectively. while D6 treatment recorded the lowest value of gene expression (0.8566 ± 0.040-fold) compared to the control LGG (one-fold). The results also demonstrated that B6 treatment was superior to the other treatments in terms of EPS formation, with a value of 481 ± 1.00 mg/100 mL, followed by the C9 treatment at 440 ± 2.00 mg/100 mL, compared to the LGG (control) reaching 199.7 ± 3.51 mg/100 mL. Also, the highest % of quantitative and qualitative β-glucan in EPS was observed in B6 followed by C9, D6 and A3 which were 5.56 ± 0.01%, 4.46 ± 0.01%, 0.25 ± 0.008% and 0.12 ± 0.008%, respectively compared to control (0.31 ± 0.01%). Finally, the presented results indicate the importance of screening the local LAB isolates to obtain a superior strain for β-glucan production which will be introduced in a subsequent study under optimum conditions.

A Sweeter Pill to Swallow: A Review of Honey Bees and Honey as a Source of Probiotic and Prebiotic Products

Honey bees and honey, have been the subject of study for decades due to their importance in improving health. At times, some of the probiotics may be transferred to the honey stored in the honeycomb. Consumers may benefit from consuming live-probiotics honey, which can aid in suppressing the reproduction of pathogens in their digestive system. Prebiotics, on the other hand, are mainly carbohydrates that promote the growth of native microflora probiotics in the digestive tract to maintain a healthy environment and improve the gut performance of the host. Therefore, this narrative review aims to present and analyze ten years’ worth of information on the probiotic and prebiotic potential of honey bees and honey since not many review articles were found discussing this topic. Results showed that not many studies have been performed on the probiotic and prebiotic aspects of honey bees and honey. If further research is conducted, isolated probiotics from the bee’s gut combined with honey’s prebiotic properties can be manipulated as potential sources of probiotics and prebiotics for human and animal benefits since they appear to be interrelated and function in symbiosis.

Antimicrobial Activity from Putative Probiotic Lactic Acid Bacteria for the Biological Control of American and European Foulbrood Diseases

The balance of the gut microbiome is important for the honey bee’s growth and development, immune function and defense against pathogens. The use of a beneficial bacteria-based strategy for the prevention and biocontrol of American foulbrood (AFB) and European foulbrood (EFB) diseases in honey bees offers interesting prospects. Lactic acid bacteria (LAB) are common inhabitants of the gastrointestinal tract of the honey bee. Among LABs associated with bee gut microbiota, Lactiplantibacillus plantarum (previously Lactobacillus plantarum) and Apilactobacillus kunkeei (formerly classified as Lactobacillus kunkeei) are two of the most abundant species. In this study, four Lactiplantibacillus plantarum strains and four Apilactobacillus kunkeei strains, isolated from the gastrointestinal tract of honey bee (Apis mellifera L.) were selected for their in vitro inhibition ability of Paenibacillus larvae ATCC 9545 and Melissococccus plutonius ATCC 35311. In addition, these LABs have been characterized through some biochemical and functional characteristics: cell surface properties (hydrophobicity and auto-aggregation), carbohydrates assimilation and enzymatic activities. The antimicrobial, biochemical and cell surface properties of these LABs have been functional to their candidature as potential probiotics in beekeeping and for the biocontrol of AFB and EFB diseases.

Development of Thermotolerant Lactobacilli Cultures with Improved Probiotic Properties Using Adaptive Laboratory Evolution Method

Probiotics play a significant role in functional foods. Heat stress and dehydration are the two principal mechanisms leading to inactivation and loss of probiotics viability in its production. There is a need to develop an industrial organism to withstand higher temperatures during its processing and storage. This current study aims to develop thermotolerant strains of Lacticaseibacillus casei N (N) and Lactobacillus helveticus NRRL B-4526 (H) by acclimatizing the wild-type strains to the higher temperature of 45 °C by adaptive laboratory evolution. A two-fold increase in biomass was observed in both acclimatized strains up to the 200th generation, which subsequently remained stable after 500 generations. The morphological change of these acclimatized strains was observed under scanning electron microscopy. Also, there was an increase in probiotic attributes of these acclimatized strains compared to their wild-types. Among two acclimatized strains, L. casei N-45 had shown higher tolerance in the acidic pH 3.0 (89.31%), the bile of 0.3% (84.45%), simulated gastric juice (79.12%), and simulated intestinal juice (73.86%). There was also an increase in salt tolerance (NaCl), radical scavenging activity, autoaggregation, coaggregation, and hydrophobicity of these adapted strains. The total protein profiling using 2D gel electrophoresis reveals the differences in protein expressions between wild-type and acclimatized strains. Specific protein spots from acclimatized strains of H-45 and N-45 were further subjected to MALDI-TOF MS/MS. Some of the identified proteins were recognized to play a role in RNA chaperones and protein synthesis during stress conditions.

Surface-enhanced Raman spectroscopy for identification of food processing bacteria

Food processing bacteria play important role in providing flavors, ingredients and other beneficial characteristics to the food but at the same time some bacteria are responsible for food spoilage. Therefore, quick and reliable identification of these food processing bacteria is very necessary for the differentiation between different species which may help in the development of more useful food processing methodologies. In this study, analysis of different bacterial species (Lactobacillus fermentum, Fructobacillus fructosus, Pediococcus pentosaceus and Halalkalicoccus jeotgali) was performed with our in-house developed Ag NPs-based surface-enhanced Raman spectroscopy (SERS) method. The SERS spectral data was analyzed by multivariate data analysis techniques including principal component analysis (PCA) and partial least square discriminant analysis (PLS-DA). Bacterial species were differentiated on the basis of SERS spectral features and potential of SERS was compared with the Raman spectroscopy (RS). SERS along with PCA and PLS-DA was found to be an efficient technique for identification and differentiation of food processing bacterial species. Differentiation with accuracy of 99.5% and sensitivity of 99.7% was depicted by PLS-DA model using leave one out cross validation.

Rainwater-driven microbial fuel cells for power generation in remote areas

The possibility of using rainwater as a sustainable anolyte in an air-cathode microbial fuel cell (MFC) is investigated in this study. The results indicate that the proposed MFC can work within a wide temperature range (from 0 to 30°C) and under aerobic or anaerobic conditions. However, the rainwater season has a distinct impact. Under anaerobic conditions, the summer rainwater achieves a promised open circuit potential (OCP) of 553 ± 2 mV without addition of nutrients at the ambient temperature, while addition of nutrients leads to an increase in the cell voltage to 763 ± 3 and 588 ± 2 mV at 30°C and ambient temperature, respectively. The maximum OCP for the winter rainwater (492 ± 1.5 mV) is obtained when the reactor is exposed to the air (aerobic conditions) at ambient temperature. Furthermore, the winter rainwater MFC generates a maximum power output of 7 ± 0.1 mWm-2 at a corresponding current density value of 44 ± 0.7 mAm-2 at 30°C. While, at the ambient temperature, the maximum output power is obtained with the summer rainwater (7.2 ± 0.1 mWm-2 at 26 ± 0.5 mAm-2). Moreover, investigation of the bacterial diversity indicates that Lactobacillus spp. is the dominant electroactive genus in the summer rainwater, while in the winter rainwater, Staphylococcus spp. is the main electroactive bacteria. The cyclic voltammetry analysis confirms that the electrons are delivered directly from the bacterial biofilm to the anode surface and without mediators. Overall, this study opens a new avenue for using a novel sustainable type of MFC derived from rainwater.

Probiotic Properties and Potentiality of Lactiplantibacillus plantarum Strains for the Biological Control of Chalkbrood Disease

Ascosphaera apis is an entomopathogenic fungus that affects honeybees. In stressful conditions, this fungus (due not only to its presence, but also to the combination of other biotic and abiotic stressors) can cause chalkbrood disease. In recent years, there has been increasing attention paid towards the use of lactic acid bacteria (LAB) in the honeybees' diets to improve their health, productivity and ability to resist infections by pathogenic microorganisms. The screening of 22 strains of Lactiplantibacillus plantarum, isolated from the gastrointestinal tracts of honeybees and beebread, led to the selection of five strains possessing high antagonistic activity against A. apis. This study focused on the antifungal activity of these five strains against A. apis DSM 3116 and DSM 3117 using different matrices: cell lysate, broth culture, cell-free supernatant and cell pellet. In addition, some functional properties and the antioxidant activity of the five L. plantarum strains were evaluated. All five strains exhibited high antagonistic activity against A. apis, good surface cellular properties (extracellular polysaccharide (EPS) production and biofilm formation) and antioxidant activity. Although preliminary, these results are encouraging, and in future investigations, the effectiveness of these bacteria as probiotics in honeybee nutrition will be tested in vivo in the context of an eco-friendly strategy for the biological control of chalkbrood disease.

Effects of Prebiotics and Probiotics on Honey Bees (Apis mellifera) Infected with the Microsporidian Parasite Nosema ceranae

Nosema ceranae is a microsporidian fungus that parasitizes the midgut epithelial cells of honey bees, Apis mellifera. Due to the role that midgut microorganisms play in bee health and immunity, food supplementation with prebiotics and probiotics may assist in the control of N. ceranae. The dietary fiber prebiotics acacia gum, inulin, and fructooligosaccharides, as well as the commercial probiotics Vetafarm Probotic, Protexin Concentrate single-strain (Enterococcus faecium), and Protexin Concentrate multi-strain (Lactobacillus acidophilus, L. plantarum, L. rhamnosus, L. delbrueckii, Bifidobacterium bifidum, Streptococcus salivarius, and E. faecium) were tested for their effect on N. ceranae spore loads and honey bee survivorship. Bees kept in cages were inoculated with N. ceranae spores and single-dose treatments were administered in sugar syrup. Acacia gum caused the greatest reduction in N. ceranae spore numbers (67%) but also significantly increased bee mortality (62.2%). However, Protexin Concentrate single-strain gave similarly reduced spore numbers (59%) without affecting the mortality. In a second experiment, multiple doses of the probiotics revealed significantly reduced spore numbers with 2.50 mg/mL Vetafarm Probotic, and 0.25, 1.25, and 2.50 mg/mL Protexin Concentrate single-strain. Mortality was also significantly reduced with 1.25 mg/mL Protexin Concentrate single-strain. N. ceranae-inoculated bees fed 3.75 mg/mL Vetafarm Probotic had higher survival than N. ceranae-inoculated bees, which was similar to that of non-inoculated bees, while N. ceranae-inoculated bees fed 2.50 mg/mL Protexin Concentrate single-strain, had significantly higher survival than both N. ceranae-inoculated and non-inoculated bees. Protexin Concentrate single-strain is promising as it can reduce N. ceranae proliferation and increase bee survivorship of infected bees, even compared to healthy, non-infected bees.

Spontaneously Fermented Fruiting Bodies of Agaricus bisporus as a Valuable Source of New Isolates of Lactic Acid Bacteria with Functional Potential

The aim of the investigation was the identification and initial study of lactic acid bacteria (LAB) isolated from spontaneously fermented (at 28 °C for 5 days) fruiting bodies of white button mushrooms (Agaricus bisporus). The isolated LAB were preliminarily characterized applying the MALDI-TOF Biotyper. Moreover, further phenotypical, genotypical characteristics as well as some functional and technological properties of the selected microorganisms (including the ability to produce exopolysaccharides, cell hydrophobicity, resistance to low pH, and bile salt) were also analyzed. Among autochthonous LAB (isolated from the tested mushroom raw material), Leuconostoc mesenteroides predominated in spontaneously fermented A. bisporus, while Lactiplantibacillus paraplantarum, Lactiplantibacillus plantarum, and Lactococcus lactis were less abundant. The highest dynamics of acidification of the mushroom material were exhibited by isolates EK55 and EK4 that, after 24 h of incubation, were able to decrease the pH of the raw material up to 5.06 ± 0.021 and 5.17 ± 0.015, respectively. Furthermore, the analysis of bacterial cell hydrophobicity indicated that the highest values of this parameter were noted for L. plantarum isolates EK12 (29.59 ± 0.7%), EK55 (28.75 ± 0.551%), and EK5 (27.33 ± 1.516%). It was revealed some of the analyzed LAB (especially isolates L. plantarum EK55 and L. paraplantarum EK4) exhibited functional and technological potential that might be used in the formulation of novel starter cultures.

Antimicrobial Activity against Paenibacillus larvae and Functional Properties of Lactiplantibacillus plantarum Strains: Potential Benefits for Honeybee Health

Paenibacillus larvae is the causative agent of American foulbrood (AFB), a severe bacterial disease that affects larvae of honeybees. The present study evaluated, in vitro, antimicrobial activity of sixty-one Lactiplantibacillus plantarum strains, against P. larvae ATCC 9545. Five strains (P8, P25, P86, P95 and P100) that showed the greatest antagonism against P. larvae ATCC 9545 were selected for further physiological and biochemical characterizations. In particular, the hydrophobicity, auto-aggregation, exopolysaccharides production, osmotic tolerance, enzymatic activity and carbohydrate assimilation patterns were evaluated. The five L. plantarum selected strains showed suitable physical and biochemical properties for their use as probiotics in the honeybee diet. The selection and availability of new selected bacteria with good functional characteristics and with antagonistic activity against P. larvae opens up interesting perspectives for new biocontrol strategies of diseases such as AFB.

Isolation, Identification and Antimicrobial Activity of Unprecedented Lactic Acid Bacterial Isolates from Honeybees

BACKGROUND AND OBJECTIVE

Lactic acid bacteria are generally recognized as safe that could be beneficial for several uses in food industry to get their health benefits. The present study was focused on the isolation and identification of some new lactic acid bacteria that might be naturally occurred in the honeybees stomach and tried to explore their benefits.

MATERIALS AND METHODS

Twenty five isolates of lactic acid bacteria were isolated from the stomach of three different types of Egyptian bees (Apis mellifera lamarckii ), Carniolan bees (A.m. carnica) and hybrid Carniolan bees. Identification of isolates was carried out based on phenotypical tests and carbohydrate assimilation using API50 CHL and 16S rDNA sequencing.

RESULTS

In the present study, the results emphasized Lactobacillus plantarum to be the predominant species (62.5%), other strains were identified as Pediococcus pentosaceus (12.5%), Lactobacillus pentosus (12.5%) and Lactobacillus sakei (12.5%). Eight of 25 isolates showed a potential antibacterial activity especially against Salmonella senftenberg strain. The novel isolates (HBMSS1, HBMSS3, HBMSS4, HBMSS5, HBMSS6 and HBMSS8) showed a significant antimicrobial activity against C. botulinum, E. coli, S. Senftenberg and S. epidermidis as food borne pathogens and P. larvae and M. plutonius as honeybee pathogens.

CONCLUSION

These promising findings might be beneficial for discovering novel preservatives in food industry and substitution of antibiotic drugs used in the treatment of honeybees' infection.

Probiotic potency of Lactobacillus plantarum KX519413 and KX519414 isolated from honey bee gut

The Indian honey bee Apis cerana indica, which harbors an abundant and diverse range of lactic acid bacteria (LAB) in their gut with beneficial effects, was used as the source for the isolation of LAB. In the present study, two LAB isolates from honey bee gut were selected primarily based on their phenotypic and selective biochemical characterization, followed by PCR and identified using 16S rRNA sequencing as Lactobacillus plantarum and were registered in National Centre for Biotechnology Information under accession number KX519413 and KX519414. The probiotic potency of test strains indicated their survivability at acidic pH, bile salts and viability in simulated gastric juice enabling them to withstand gastrointestinal tract conditions. Evaluation of cell surface properties suggested that they possess an important defense mechanism against the pathogen since they are hydrophobic, auto-aggregative and have co-aggregative ability. Further, efficient exopolysaccharide production by them indicates not only their ability to enrich biofilm formation and auto-aggregation, but also enhances bacterial adhesion and colonization on the host intestinal tract. The present study concluded that L. plantarum from the gut of Apis cerana indica possesses probiotic potency, and potential candidates for use as food besides application in nutraceutical and pharmaceutical industries.

Honey as a functional additive in yoghurt – a review

Purpose

Recent societal interest in healthful foods has led to the development of functional dairy products that basically provide health benefits in addition to their fundamental nutrients. Yoghurt being most popular fermented milk product due to its healthy image can be an excellent carrier for probiotics. Functional properties of yoghurt can be enhanced with the inclusion of functional ingredients such as probiotics and its conjugate application with prebiotics may be advantageous as it favors probiotic growth. Nutritional and medicinal value of honey coupled with presence of oligosaccharides has projected honey as a functional additive in yoghurt.

Design/methodology/approach

Attempt has been made to review the literature on the biochemical activities of yoghurt cultures and probiotics in presence of honey. Both review and research papers related to biochemical activities and functional properties of yoghurt cultures and probiotics in presence of honey and their health benefits published in diverse journals under Pub Med and Science Direct have been considered. Keywords used for data search included functional foods, yoghurt, probiotic, health benefits, honey, etc.

Findings

Functional properties of yoghurt can be further enhanced with the inclusion of probiotic cultures and honey. Honey can be safely used in association with different probiotic cultures during yoghurt manufacture for augmenting functional properties of yoghurt to extend health benefits. Honey may not be equally a suitable matrix for all yoghurt cultures or probiotic cultures.

Research limitations/implications

Reviewed literature indicated that limited research on animal or human feeding trials with honey containing yoghurt has been done. Clinical trials with honey containing yoghurt are emerging prior to its marketing as functional food.

Originality/value

Application of honey as a functional additive during the manufacture of probiotic yoghurt is suggested to extend the functional properties of normal yoghurt.

Alterations in honey bee gut microorganisms caused by Nosema spp. and pest control methods

BACKGROUND

Honey bees are associated with gut microorganisms essential for their nutrition and health. The composition of the microbial community can be used as a biological health indicator and is characterized using biomarker fatty acids. Commonly, gut microorganisms are exposed to pathogens and to an array of chemical and biological pest control methods.

RESULTS

We found a strong negative effect on microbial gut community composition when exposed to the bee pest control chemicals oxytetracycline, oxalic acid and imidacloprid, and when inoculated with the bee pest Nosema spp. and the potential bee pest biocontrol agent Lactobacillus plantarum. Results from the in vitro test with bee pest chemicals showed a differential response of Lactobacillus spp. At the community level, some taxonomic groups were more affected depending on treatment, but sharp changes in the microbial structure were caused by compounds generally considered as bee safe.

CONCLUSION

Our results show that pests such as Nosema spp. and pest control methods alter the composition of bee gut microorganisms, which may have severe consequences for pathogen defense, physiology and general honey bee health. In addition, L. plantarum has potential as a biocontrol agent against Nosema spp. © 2018 Society of Chemical Industry.

Gram-Positive Bacteria with Probiotic Potential for the Apis mellifera L. Honey Bee: The Experience in the Northwest of Argentina

Apis mellifera L. is one of the most important natural pollinators of significant crops and flowers around the world. It can be affected by different types of illnesses: american foulbrood, nosemosis, varroasis, viruses, among others. Such infections mainly cause a reduction in honey production and in extreme situations, the death of the colony. Argentina is the world's second largest honey exporter and the third largest honey producer, after China and Turkey. Given both the prominence of the honey bee in nature and the economic importance of apiculture in Argentina and the world, it is crucial to develop efficient and sustainable strategies to control honey bee diseases and to improve bee colony health. Gram-positive bacteria, such as lactic acid bacteria, mainly Lactobacillus, and Bacillus spp. are promising options. In the Northwest of Argentina, several Lactobacillus and Bacillus strains from the honey bee gut and honey were isolated by our research group and characterized by using in vitro tests. Two strains were selected because of their potential probiotic properties: Lactobacillus johnsonii CRL1647 and Bacillus subtilis subsp. subtilis Mori2. Under independent trials with both experimental and commercial hives, it was determined that each strain was able to elicit probiotic effects on bee colonies reared in the northwestern region of Argentina. One result was the increase in egg-laying by the queen which therefore produced an increase in bee number and, consequently, a higher honey yield. Moreover, the beneficial bacteria reduced the incidence of two important bee diseases: nosemosis and varroosis. These results are promising and extend the horizon of probiotic bacteria to the insect world, serving beekeepers worldwide as a natural tool that they can administer as is, or combine with other disease-controlling methods.

Potential probiotic-associated traits revealed from completed high quality genome sequence of Lactobacillus fermentum 3872

The article provides an overview of the genomic features of Lactobacillus fermentum strain 3872. The genomic sequence reported here is one of three L. fermentum genome sequences completed to date. Comparative genomic analysis allowed the identification of genes that may be contributing to enhanced probiotic properties of this strain. In particular, the genes encoding putative mucus binding proteins, collagen-binding proteins, class III bacteriocin, as well as exopolysaccharide and prophage-related genes were identified. Genes related to bacterial aggregation and survival under harsh conditions in the gastrointestinal tract, along with the genes required for vitamin production were also found.

Establishment of Lactobacillus plantarum strain in honey bee digestive tract monitored using gfp fluorescence

Lactic acid bacteria are symbiotic bacteria that naturally reside in the gastrointestinal tract of honey bees. They serve a multitude of functions and are considered beneficial and completely harmless. In our experiments Lactobacillus plantarum strain B35, isolated from honey bee digestive tract, was modified using pAD43-25 plasmid carrying a functional GFP gene sequence (gfpmut3a) and used as a model for monitoring and optimisation of the mode of application. The establishment of this strain in honey bee digestive tract was monitored using GFP fluorescence. Three different modes of oral application of this strain were tested: water suspension of lyophilised bacteria, aerosol application of these bacteria and consumption of sugar honey paste containing the lyophilised lactobacilli. Two days after administration the L. plantarum B35-gfp was present throughout the honey bee digestive tract with 10⁴-10⁵ cfu/bee with highest count observed for aerosol application.

Effect of Lactobacillus johnsonii CRL1647 on different parameters of honeybee colonies and bacterial populations of the bee gut

Lactobacillus johnsonii CRL1647, isolated from the intestinal tract of a worker-bee in Salta, Argentina, was delivered to Apis mellifera L. honey bee colonies according to two different administration schedules: 1×105 cfu/ml every 15 days (2011) or monthly (2012). The effect of each treatment on the bee-colony performance was monitored by measuring honey production, and the prevalence of varroasis and nosemosis. Worker bees from each assay were randomly captured 3 days after administration and assayed for the following intestinal culturable and defined bacterial populations: total aerobic microorganisms, Bacillus spp. spores, Lactobacillus spp., Enterococcus spp. and enterobacteria. Interestingly, both treatments generated a similar increase in honey production in treated colonies compared to controls: 36.8% (every 15 days) and 36.3% (monthly). Nosema index always exhibited a reduction when lactobacilli were administered; in turn, Varroa incidence was lower when the lactobacilli were administered once a month. Moreover, the administration of L. johnsonii CRL1647 every 15 days produced an increase in the total number of aerobic microorganisms and in bacteria belonging to the genera Lactobacillus and Enterococcus; at the same time, a decrease was observed in the number of total spores at the end of the treatment. The number of enterobacteria was constant and remained below that of control hives at the end of the assay. On the other hand, the delivery of lactobacilli once a month only showed an increase in the number of bacteria belonging to the genus Lactobacillus; meanwhile, viable counts of the remaining microorganisms assayed were reduced. Even though it seems that both treatments were similar, those bee colonies that received L. johnsonii CRL1647 every 15 days became so strong that they swarmed.

Are commercial probiotics and prebiotics effective in the treatment and prevention of honeybee nosemosis C?

The study was conducted to investigate the effect of Lactobacillus rhamnosus (a commercial probiotic) and inulin (a prebiotic) on the survival rates of honeybees infected and uninfected with Nosema ceranae, the level of phenoloxidase (PO) activity, the course of nosemosis, and the effect on the prevention of nosemosis development in bees. The cells of L. rhamnosus exhibited a high rate of survival in 56.56 % sugar syrup, which was used to feed the honeybees. Surprisingly, honeybees fed with sugar syrup supplemented with a commercial probiotic and a probiotic + prebiotic were more susceptible to N. ceranae infection, and their lifespan was much shorter. The number of microsporidian spores in the honeybees fed for 9 days prior to N. ceranae infection with a sugar syrup supplemented with a commercial probiotic was 25 times higher (970 million spores per one honeybee) than in a control group fed with pure sucrose syrup (38 million spores per one honeybee). PO activity reached its highest level in the hemolymph of this honeybee control group uninfected with N. ceranae. The addition of probiotics or both probiotics and prebiotics to the food of uninfected bees led to the ~2-fold decrease in the PO activity. The infection of honeybees with N. ceranae accompanied an almost 20-fold decrease in the PO level. The inulin supplemented solely at a concentration of 2 μg/mL was the only administrated factor which did not significantly affect honeybees’ survival, the PO activity, or the nosemosis infection level. In conclusion, the supplementation of honeybees’ diet with improperly selected probiotics or both probiotics and prebiotics does not prevent nosemosis development, can de-regulate insect immune systems, and may significantly increase bee mortality.

Overexpression and optimization of glutamate decarboxylase in Lactobacillus plantarum Taj-Apis362 for high gamma-aminobutyric acid production

Gamma-aminobutyric acid (GABA) is an important bioactive compound biosynthesized by microorganisms through decarboxylation of glutamate by glutamate decarboxylase (GAD). In this study, a full-length GAD gene was obtained by cloning the template deoxyribonucleic acid to pTZ57R/T vector. The open reading frame of the GAD gene showed the cloned gene was composed of 1410 nucleotides and encoded a 469 amino acids protein. To improve the GABA-production, the GAD gene was cloned into pMG36e-LbGAD, and then expressed in Lactobacillus plantarum Taj-Apis362 cells. The overexpression was confirmed by SDS-PAGE and GAD activity, showing a 53 KDa protein with the enzyme activity increased by sevenfold compared with the original GAD activity. The optimal fermentation conditions for GABA production established using response surface methodology were at glutamic acid concentration of 497.973 mM, temperature 36°C, pH 5.31 and time 60 h. Under the conditions, maximum GABA concentration obtained (11.09 mM) was comparable with the predicted value by the model at 11.23 mM. To our knowledge, this is the first report of successful cloning (clone-back) and overexpression of the LbGAD gene from L. plantarum to L. plantarum cells. The recombinant Lactobacillus could be used as a starter culture for direct incorporation into a food system during fermentation for production of GABA-rich products.