Transmission of a Protease-Secreting Bacterial Symbiont Among Pea Aphids via Host Plants

Aphids are economically important pest insects that damage plants by phloem feeding and the transmission of plant viruses. Their ability to feed exclusively on nutritionally poor phloem sap is dependent on the obligatory symbiotic bacterium Buchnera aphidicola, but additional facultative symbionts may also be present, a common example of which is Serratia symbiotica. Many Serratia species secrete extracellular enzymes, so we hypothesised that S. symbiotica may produce proteases that help aphids to feed on plants. Molecular analysis, including fluorescence in situ hybridization (FISH), revealed that S. symbiotica colonises the gut, salivary glands and mouthparts (including the stylet) of the pea aphid Acyrthosiphon pisum, providing a mechanism to transfer the symbiont into host plants. S. symbiotica was also detected in plant tissues wounded by the penetrating stylet and was transferred to naïve aphids feeding on plants containing this symbiont. The maintenance of S. symbiotica by repeated transmission via plants may explain the high frequency of this symbiont in aphid populations. Proteomic analysis of the supernatant from a related but cultivable S. symbiotica strain cultured in liquid medium revealed the presence of known and novel proteases including metalloproteases. The corresponding transcripts encoding these S. symbiotica enzymes were detected in A. pisum and in plants carrying the symbiont, although the mRNA was much more abundant in the aphids. Our data suggest that enzymes from S. symbiotica may facilitate the digestion of plant proteins, thereby helping to suppress plant defense, and that the symbionts are important mediators of aphid–plant interactions

High-Throughput Cultivation for the Selective Isolation of Acidobacteria From Termite Nests

Microbial communities in the immediate environment of socialized invertebrates can help to suppress pathogens, in part by synthesizing bioactive natural products. Here we characterized the core microbiomes of three termite species (genus Coptotermes) and their nest material to gain more insight into the diversity of termite-associated bacteria. Sampling a healthy termite colony over time implicated a consolidated and highly stable microbiome, pointing toward the fact that beneficial bacterial phyla play a major role in termite fitness. In contrast, there was a significant shift in the composition of the core microbiome in one nest during a fungal infection, affecting the abundance of well-characterized Streptomyces species (phylum Actinobacteria) as well as less-studied bacterial phyla such as Acidobacteria. High-throughput cultivation in microplates was implemented to isolate and identify these less-studied bacterial phylogenetic group. Amplicon sequencing confirmed that our method maintained the bacterial diversity of the environmental samples, enabling the isolation of novel Acidobacteriaceae and expanding the list of cultivated species to include two strains that may define new species within the genera Terracidiphilus and Acidobacterium

GABA-Producing Natural Dairy Isolate From Artisanal Zlatar Cheese Attenuates Gut Inflammation and Strengthens Gut Epithelial Barrier in vitro

Probiotic bacteria are recognized for their health-promoting properties, including maintenance of gut epithelial integrity and host immune system homeostasis. Taking into account the beneficial health-promoting effects of GABA, the presence of the gadB gene, encoding glutamate decarboxylase that converts L-glutamate to GABA, was analyzed in Lactic Acid Bacteria (LAB) natural isolates from Zlatar cheese. The results revealed that 52% of tested Lactobacillus spp. and 8% of Lactococcus spp. isolates harbor the gadB gene. Qualitative and quantitative analysis of GABA production performed by thin-layer chromatography (TLC) and high-performance liquid chromatography (HPLC) revealed the highest GABA production by Lactobacillus brevis BGZLS10-17. Since high GABA-producing LAB natural isolates are the most valuable source of naturally produced GABA, the probiotic properties of BGZLS10-17 were characterized. This study demonstrated high adhesion of BGZLS10-17 strain to Caco-2 cells and the ability to decrease the adhesion of Escherichia coli ATCC25922 and Salmonella enterica C29039. Treatment of differentiated Caco-2 cells monolayer with BGZLS10-17 supernatant containing GABA alleviated inflammation (production of IL-8) caused by IL-1β and significantly stimulated the expression of tight junction proteins (zonulin, occludin, and claudin 4), as well as the expression of TGF-β cytokine leading to the conclusion that immunosuppression and strengthening the tight junctions can have significant role in the maintenance of intestinal epithelial barrier integrity. Taken together the results obtained in this study support the idea that using of GABA producing BGZLS10-17 probiotic strain could be a good strategy to modulate immunological response in various inflammatory diseases, and at the same time, it could be a good candidate for adjunct starter culture for production of GABA-enriched dairy foods and beverages offering new perspectives in designing the novel functional foods

Health-related quality of life in elderly patients hospitalized with chronic heart failure

Background: Chronic heart failure is a very common condition in the elderly, characterized not only by high mortality rates, but also by a strong impact on health-related quality of life (HRQOL). Previous studies of HRQOL in elderly heart failure subjects have included mostly outpatients, and little is known about determinants of HRQOL in hospitalized elderly population, especially in Serbia. In this study, we tried to identify factors that influence HRQOL in elderly patients hospitalized with chronic heart failure in Serbia. Methods: The study population consisted of 136 patients aged 65 years or older hospitalized for chronic heart failure. HRQOL was assessed using the Minnesota Living with Heart Failure questionnaire. Predictors of HRQOL were identified by multiple linear regression analysis. Results: Univariate analysis showed that patients with lower income, a longer history of chronic heart failure, and longer length of hospital stay, as well as those receiving aldosterone antagonists and digoxin, taking multiple medications, in a higher NYHA class, and showing signs of depression and cognitive impairment had significantly worse HRQOL. Presence of depressive symptoms (P<0.001), higher NYHA class (P=0.021), lower income (P=0.029), and longer duration of heart failure (P=0.049) were independent predictors of poor HRQOL. Conclusion: Depressive symptoms, higher NYHA class, lower income, and longer duration of chronic heart failure are independent predictors of poor HRQOL in elderly patients hospitalized with chronic heart failure in Serbia. Further, there is an association between multiple medication usage and poor HRQOL, as well as a negative impact of cognitive impairment on HRQOL. Hence, measures should be implemented to identify such patients, especially those with depressive symptoms, and appropriate interventions undertaken in order to improve their HRQOL.publishedVersio

The Impact of Immunological Factors on Depression Treatment – Relation Between Antidepressants and Immunomodulation Agents

It is determined that 30% of patients with depression are resistant to antidepressant medication. The increased concentration of inflammation factors, such as C-reactive protein, and pro-inflammatory cytokines, have been detected in serum in these patients. It is necessary to establish new therapeutic possibilities and protocols that are created to overcome the difficulties caused by increased concentration of inflammatory biomarkers in depressive patients. The Selective Serotonin Reuptake Inhibitors (SSRIs) are considered to be the most powerful antidepressants, increasing the level of serotonin in endogenous depression, as well as in that caused by immunological mechanisms. It is believed that agents that influence cytokines, immunological signal pathways and cytokine syntheses, like the inhibitors of cyclooxygenase enzyme and other non-steroidal anti-inflammatory drugs (NSAIDs), are very important in the potential treatment of residual symptoms of depression. Treatment with cytokine antagonists is one of the potential adjuvant therapies, along with antidepressants. Signal pathways blockers, such as the inhibitors of cyclooxygenase and other NSAIDs, are in the phase of research, in terms of their antidepressant effects. Also, it has been shown that the inhibition of indolamin-2,3 deoxygenase (IDO) and kynurenine (KYN) signal pathways in the synthesis of neurotransmitters, by application of IDO antagonists, are leading to suppression of pro-inflammatory cytokine effects. Antidepressants may have anti-inflammatory effects, depending on dose and type, and they achieve this effect through the decrease of pro-inflammatory cytokine production and increase of anti-inflammatory cytokines. Also, antidepressants modulate the humoral and cellular immune system. This work aims to summarise certain neurobiological and neuroimmunological specificities that have been observed in patients with depression, antidepressants and immunomodulation agents. The understanding of complex and heterogenic pathophysiology of depression through the prism of the altered immune system, is of major importance, in terms of better optimisation of pharmacotherapy, and options for a personalised approach in depressive disorder treatment

Culture-Independent and Culture-Dependent Characterization of the Black Soldier Fly Gut Microbiome Reveals a Large Proportion of Culturable Bacteria with Potential for Industrial Applications

Black soldier fly larvae (BSFL) are fast-growing, resilient insects that can break down a variety of organic substrates and convert them into valuable proteins and lipids for applications in the feed industry. Decomposition is mediated by an abundant and versatile gut microbiome, which has been studied for more than a decade. However, little is known about the phylogeny, properties and functions of bacterial isolates from the BSFL gut. We therefore characterized the BSFL gut microbiome in detail, evaluating bacterial diversity by culture-dependent methods and amplicon sequencing of the 16S rRNA gene. Redundant strains were identified by genomic fingerprinting and 105 non-redundant isolates were then tested for their ability to inhibit pathogens. We cultivated representatives of 26 genera, covering 47% of the families and 33% of the genera detected by amplicon sequencing. Among these isolates, we found several representatives of the most abundant genera: Morganella, Enterococcus, Proteus and Providencia. We also isolated diverse members of the less-abundant phylum Actinobacteria, and a novel genus of the order Clostridiales. We found that 15 of the isolates inhibited at least one of the tested pathogens, suggesting a role in helping to prevent colonization by pathogens in the gut. The resulting culture collection of unique BSFL gut bacteria provides a promising resource for multiple industrial applications

Identification and characterization of lactic acid bacteria isolated from artisanal white brined Golija cows’ milk cheeses

The aim of this study was to identify and characterize the lactic acid bacteria (LAB) of artisanal Golija raw and cooked cows' milk cheeses traditionally manufactured without the addition of starter culture. A total of 188 Gram-positive and catalase-negative isolates of Golija cheeses were obtained from seven samples of different ripening time. Phenotype-based assays as well as rep-PCR and 16S rDNA sequence analysis were undertaken for all 188 LAB strains. The most diverse species were isolated from 20-day-old BGGO8 cheese (Lactobacillus fermentum, Lactobacillus plantarum, Lactobacillus casei/paracasei, Lactobacillus sucicola, Lactococcus lactis subsp. lactis, Lactococcus lactis subsp. lactis by. diacetylactis, Enterococcus faecium, Enterococcus durans and Leuconostoc mesenteroides). In other Golija cheeses Lactobacillus reuteri, Lactobacillus curvatus, Lactobacillus rhamnosus, Lactococcus lactis subsp. cremoris, Lactococcus garvieae, Streptococcus thermophilus and Leuconostoc pseudomesenteroides were found. Pronounced antimicrobial properties showed enterococci (13/42) and lactococci (12/31), while the good proteolytic activity demonstrated lactococci (13/31) and lactobacilli (10/29)

Correlation of gut microbiota composition with resistance to experimental autoimmune encephalomyelitis in rats

Multiple sclerosis is a chronic inflammatory disease of the central nervous system (CNS). It is widely accepted that autoimmune response against the antigens of the CNS is the essential pathogenic force in the disease. It has recently become increasingly appreciated that activated encephalitogenic cells tend to migrate towards gut associated lymphoid tissues (GALT) and that interrupted balance between regulatory and inflammatory immunity within the GALT might have decisive role in the initiation and propagation of the CNS autoimmunity. Gut microbiota composition and function has the major impact on the balance in the GALT. Thus, our aim was to perform analyses of gut microbiota in experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis. Albino Oxford (AO) rats that are highly resistant to EAE induction and Dark Agouti (DA) rats that develop EAE after mild immunization were compared for gut microbiota composition in different phases after EAE induction. Microbial analyses of the genus Lactobacillus and related lactic acid bacteria showed higher diversity of Lactobacillus spp. in EAE-resistant AO rats, while some members of Firmicutes and Proteobacteria (Undibacterium oligocarboniphilum) were detected only in faeces of DA rats at the peak of the disease (between 13 and 16 days after induction). Interestingly, Turicibacter sp. that was found exclusively in non-immunized AO, but not in DA rats in our previous study was detected in DA rats that remained healthy 16 days after induction. Similar observation was obtained for the members of Lachnospiraceae. As dominant presence of the members of Lachnospiraceae family in gut microbial community has been linked with mild symptoms of various diseases, it is tempting to assume that Turicibacter sp. and Lachnospiraceae contribute to the prevention of EAE development and the alleviation of the disease symptoms. Further, production of a typical regulatory cytokine interleukin-10 was compared in GALT cells of AO and DA rats, and higher production was observed in DA rats. Our data contribute to the idea that gut microbiota and GALT considerably influence multiple sclerosis pathogenesis

Characterization of lactic acid bacteria isolated from Bosnian artisanal dry fermented sausage (sudzuk) during fermentation

Bosnian sudzuk is a dry fermented sausage produced in a rural household near the town of Visoko in central Bosnia and Herzegovina. This kind of sausage was manufactured only from beef and spices in a traditional way without the addition of a starter cultures. To identify lactic acid bacteria (LAB), a total number of 160 LAB strains were isolated from five samples of Bosnian sudzuk collected over 28 days of fermentation. Preliminary identification by phenotypic tests and 16S rDNA sequencing were performed for all 160 of the LAB isolates. Identification of LAB strains from traditionally produced Bosnian sausage at the species level revealed the presence of six genera: Lactococcus sp., Enterococcus sp., Leuconostoc sp., Lactobacillus sp., Pediococcus sp. and Weissella sp.. Among the 15 distinct species identified, the species Lactobacillus plantarum, Leuconostoc mesenteroides, Lactococcus lactis, Enterococcus faecalis and Enterococcus durans were present throughout the entire process of fermentation. Leuconostoc mesenteroides, Lactobacillus plantarum and Lactococcus lactis prevailed, with 21.8%, 19.3% and 13.1%, respectively, of total LAB strains during the entire fermentation process. Significant negative correlations (r = 0.892 and r = 0.829, respectively) between the presence of Weissella sp. and Lactobacillus sp., and between the presence of Weissella sp. and Lactococcus sp. were recorded. Lactobacillus plantarum, Enterococcus durans and Leuconostoc mesenteroides were the best producers of aromogenic compounds while 32.3% of Lactobacillus plantarum and 28.6% of Leuconostoc mesenteroides were produced exopolysaccharides