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Aims: The Mediterranean fruit fly (the medfly) causes major losses of agricultural fruits. Its microbiome is mainly composed of various Enterobacteriaceae that contribute to nutrient acquisition and are associated with the fly's development. Moreover, the performance of males produced by the sterile insect technique is improved by providing mass‐reared insects with specific gut bacteria. Bdellovibrio and like organisms (BALOs) are obligate predators of Gram‐negative bacteria that efficiently preys upon diverse Enterobacteriaceae, making it a potential disruptor of the fly's microbiome. We hypothesized that the fly's microbiome can be targeted to control the insect. Methods and Results: Inoculation of B. bacteriovorus as free‐swimming or encapsulated cells into gut extracts significantly reduced gut bacterial abundance, sustaining predator survival. Similar treatments applied to adult flies showed that the predators also survived in the gut environment. While addition of the predators did not affect total gut bacterial abundance and end‐point fly mortality, a shift in the gut community structure, measured by high‐throughput community sequencing was observed. Conclusions: The bacterial predator of bacteria B. bacteriovorus can prey and survive in vivo in the medfly gut. Significance and Impact of the Study: This study establishes the potential of BALOs to affect the microbiome of insect hosts. [ABSTRACT FROM AUTHOR]

Abstract: Aim: To detect marine Bdellovibrio and like organisms (BALOs) which are able to infect Vibrio parahaemolyticus from seawater of the Adriatic, Italy. To test, prey specificity and predation efficiency of our Halobacteriovorax isolate, named HBXCO1, towards 17 Vibrio and 7 non‐Vibrio strains linked to the Adriatic sea, Italy. Methods and Results: Double layer agar plating technique was used to enumerate BALOs and to evaluate their prey specificity and predation efficiency. Transmission electron microscopy and 16S rRNA analysis were used to identify them. Means of BALOs counts ranged from 5·0 PFU per ml (March 2017) to 98·6 PFU per ml (August 2016). HBXCO1 had the ability to attack all tested prey strains of V. parahaemolyticus, Vibrio cholerae non‐O1/O139 and Vibrio vulnificus, but it did not prey on non‐Vibrio strains and V. alginolyticus under the tested conditions. Conclusions: Bdellovibrio and like organisms capable of infecting pathogenic vibrios are naturally present in seawater of the Adriatic, Italy. Isolate HBXCO1 shows prey specificity preferentially for the Vibrio genus and high predatory efficiency towards a wide range of pathogenic strains. Significance and Impact of the Study: The public impact of V. parahaemolyticus, non‐O1/O139 V. cholerae and V. vulnificus in bivalves is relevant and current decontamination processes are not always effective. We believe that the predator HBXCO1 represents a potential candidate for the development of strategies of biocontrol of pathogenic vibrios in bivalves from harvesting to trade. [ABSTRACT FROM AUTHOR]

Abstract: Aims: (i) To obtain and identify the predatory bacteria for the control of contaminated bacteria and to promote the autotrophic growth of Chlorella USTB‐01. (ii) To identify and measure the different cell numbers in microalgal culture using flow cytometer. Methods and Results: A predatory bacterial strain was isolated using Escherichia coli BL21 as a sole prey host, which was identified as Bdellovibrio USTB‐06 by the analysis of 16S rDNA sequence. A flow cytometer was successfully used to identify and measure the cell numbers of Chlorella USTB‐01, the contaminated bacteria and Bdellovibrio USTB‐06 simultaneously in the autotrophic culture of Chlorella USTB‐01 according to the identification of the different cell sizes. With the addition of Bdellovibrio USTB‐06 at initial 104 plaque‐forming units per ml, the contaminated bacteria severely decreased by about five counts (in log10 CFU per ml) and the growth of Chlorella USTB‐01 was greatly increased by 37·0% compared with those of control respectively. Conclusions: Bdellovibrio USTB‐06 could effectively promote the growth of Chlorella USTB‐01 via the killing of the contaminated bacteria. Significance and Impact of the Study: Our study reveals a good biotechnology method to increase the growth of Chlorella USTB‐01 which is very important in the industry of microalgal culture. [ABSTRACT FROM AUTHOR]

Standard aquaculture generates large-scale pollution and strains water resources. In aquaculture using zero discharge systems ( ZDS), highly efficient fish growth and water recycling are combined. The wastewater stream is directed through compartments in which beneficial microbial activities induced by creating suitable environmental conditions remove biological and chemical pollutants, alleviating both problems. Bacterial predators, preying on bacterial populations in the ZDS, may affect their diversity, composition and functional redundancy, yet in-depth understanding of this phenomenon is lacking. The dynamics of populations belonging to the obligate predators Bdellovibrio and like organisms ( BALOs) were analyzed in freshwater and saline ZDS over a 7-month period using QPCR targeting the Bdellovibrionaceae, and the Bacteriovorax and Bacteriolyticum genera in the Bacteriovoracaeae. Both families co-existed in ZDS compartments, constituting 0.13-1.4% of total Bacteria. Relative predator abundance varied according to the environmental conditions prevailing in different compartments, most notably salinity. Strikingly, the Bdellovibrionaceae, hitherto only retrieved from freshwater and soil, also populated the saline system. In addition to the detected BALOs, other potential predators were highly abundant, especially from the Myxococcales. Among the general bacterial population, Flavobacteria, Bacteroidetes, Fusobacteriaceae and unclassified Bacteria dominated a well mixed but seasonally fluctuating diverse community of up to 238 operational taxonomic units, as revealed by 16 S r RNA gene sequencing. [ABSTRACT FROM AUTHOR]

To characterize freshwater Bdellovibrio-and-like organisms (BALO) isolated in China and examine their potential in controlling growth of Salmonella enterica ssp. enterica serovar Typhimurium on tilapia fillets. Four BALO isolates were recovered from a pond in Yanzhou of Shandong province, China, with Salm. Typhimurium as prey using double-layer agar method. Partial 16S rDNA sequencing analysis identified BD2GL, BD5GL and BDXGL as Bdellovibrio bacteriovorus and BD2GS as a Peredibacter sp. Lysis experiments on 32 potentially pathogenic strains revealed that BALO lysis rates are in the range of 56·3-65·6%. On the five Salmonella strains tested, only BD2GS achieved 100% lysis rate. When applied on tilapia fillets against Salm. Typhimurium, BD2GS showed its growth control potential. Cell increments of Salm. Typhimurium were significantly lower ( P < 0·05) in two BD2GS-treated groups compared to control and low-dose group (BD2GS to prey ratio, 1 : 1) was more effective than high-dose group (BD2GS to prey ratio, 10 : 1) in controlling Salm. Typhimurium growth. Results of this study indicated that BD2GS could control Salm. Typhimurium growth on tilapia fillets. BALO could be used as a live protective culture in controlling bacterial growth and ensure food safety. [ABSTRACT FROM AUTHOR]

Aims: To apply and compare two PCR-based methods for typing saltwater Bdellovibrio-and-like organisms (BALOs) and to understand ecological and phylogenetic aspects of the BALOs isolated from shrimp mariculture systems. Methods and Results: Using double-layer agar technique, the numbers of culturable BALOs that lyse Vibrio alginolyticus were found to be 10–103 PFU ml−1 in the surface water samples. A total of 130 BALOs isolates were differentiated into five phylotypes by denaturing gradient gel electrophoresis targeting the 16S rDNA V3 region and four phylotypes by amplified rDNA restriction analysis of the Bacteriovoracaceae-specific 16S rDNA fragment respectively. Phylogenetic analysis of representative isolates showed that all of them were identified as Bacteriovorax spp., but affiliated with four different clusters in the family Bacteriovoracaceae. Conclusions: The two PCR-based methods both can be chosen to rapidly type the saltwater BALOs at cluster level. And the relatively large numbers of BALOs with various phylotypes recovered from the same habitats suggested that these predators might play important ecological role in shrimp mariculture environments. Significance and Impact of the Study: We proposed two effective methods to distinguish rapidly large numbers of BALOs isolates and our results would be helpful to understand the diversity and function of BALOs in mariculture environments. [ABSTRACT FROM AUTHOR]

Aims: Isolation and characterization of new bacterial strains capable of degrading nonylphenol ethoxylates (NP nEO) with a low ethoxylation degree, which are particularly recalcitrant to biodegradation. Methods and Results: Seven aerobic bacterial strains were isolated from activated sludges derived from an Italian plant receiving NP nEO-contaminated wastewaters after enrichment with a low-ethoxylated NP nEO mixture. On the basis of 16S rDNA sequence, the strains were positioned into five genera: Ochrobactrum, Castellaniella, Variovorax, Pseudomonas and Psychrobacter. Their degradation capabilities have been evaluated on two commercial mixtures, i.e. Igepal CO-210 and Igepal CO-520, the former rich in low ethoxylated congeners and the latter containing a broader spectrum of NP nEO, and on 4- n-nonylphenol (NP). The strains degraded Igepal CO-210, Igepal CO-520 and 4- n-NP all applied at the initial concentration of 100 mg l−1, by 35–75%, 35–90% and 15–25%, respectively, after 25 days of incubation. Conclusions: Some of the isolated strains, in particular the Pseudomonas strains BCb12/1 and BCb12/3, showed interesting degradation capabilities towards low ethoxylated NP nEO congeners maintaining high cell vitality. Significance and Impact of the Study: Increased knowledge of bacteria involved in NP nEO degradation and the possibility of using the isolated strains in tailored process for a tertiary biological treatment of effluents of wastewater treatment plants. [ABSTRACT FROM AUTHOR]

Abstract: Bdellovibrio-and-like organisms (BALOs) are predatory bacteria that prey upon Gram-negative bacteria and are taxonomically subsumed in the order Bdellovibrionales. Despite their unique lifestyle, these bacteria show remarkable genotypic diversities. The outer membrane of the predators is likely to play an important role during the recognition and invasion stage, as well as in the intraperiplasmic growth phase. In this study, the outer membrane protein fractions of type strains of Bdellovibrio, Bacteriovorax and Peredibacter were investigated, revealing the presence of outer membrane proteins (Omps) similar to the major Omps of Bdellovibrio bacteriovorus. The primary structures of these Omps of Bdellovibrio sp. W, Bacteriovorax stolpii and Peredibacter starrii were elucidated by a combined mass spectrometric–reverse genetic approach. The similarity between the analyzed Omps of the investigated BALOs ranges from 32% to 89% showing conserved amino acid regions in their primary structure. [Copyright &y& Elsevier]