688. Phage-organism relationships among strains ofStreptococcus cremoris: the selection of strains as cheese starters

1957 ◽  
Vol 24 (3) ◽  
pp. 381-386 ◽  
Author(s):  
H. R. Whitehead ◽  
Elizabeth J. Bush
Keyword(s):  
Host Range ◽  
Bacterial Strain ◽  
Bacterial Strains ◽  
Clear Cut ◽  
Phage Multiplication ◽  
Selection Of ◽  
Family Groups

The relationships between nineteen strains ofStr. cremorisand nineteen phage races were investigated. It was found that in addition to clear-cut lytic reactions there were other actions between some phage races and bacterial strains whereby in some cases a phage could show adaptation to a strain and become changed in host range, and in other cases could inhibit growth of a strain without any phage multiplication.There is some evidence to indicate that bacterial strains and phage races fall into family groups within which most of the phages act in one way or another on most of the strains. The suggestion is made that the strains and races in a group may have originated from a parent bacterial strain and parent phage race.The selection of strains ofStr. cremorisfor use as cheese starters is discussed in the light of the findings reported in the present paper. The diffculty of isolating a large number of strains unrelated in every respect is indicated.

scholarly journals Effect of TiO2 on Selected Pathogenic and Opportunistic Intestinal Bacteria

2021 ◽  
Author(s):  
Ewa Baranowska-Wójcik ◽  
Dominik Szwajgier ◽  
Klaudia Gustaw
Keyword(s):  
Titanium Dioxide ◽  
Bacterial Strain ◽  
Intestinal Bacteria ◽  
Food Additive ◽  
Bacterial Strains ◽  
Gastrointestinal Microbiota ◽  
Food Grade ◽  
The Eu

AbstractFood-grade titanium dioxide (TiO2) containing a nanoparticle fraction (TiO2 NPs-nanoparticles) is widely used as a food additive (E171 in the EU). In recent years, questions concerning its effect on the gastrointestinal microbiota have been raised. In the present study, we examined interactions between bacteria and TiO2. The study involved six pathogenic/opportunistic bacterial strains and four different-sized TiO2 types: three types of food-grade E171 compounds and TiO2 NPs (21 nm). Each bacterial strain was exposed to four concentrations of TiO2 (60, 150, 300, and 600 mg/L TiO2). The differences in the growth of the analyzed strains, caused by the type and concentration of TiO2, were observed. The growth of a majority of the strains was shown to be inhibited after exposure to 300 and 600 mg/L of the food-grade E171 and TiO2 NPs.

scholarly journals Phenotypically and Genotypically Heterogeneous Strains of Pseudomonas syringae Associated With Alfalfa Leaf Spot Disease in Iran

Plant Disease ◽  
2019 ◽  
Vol 103 (12) ◽  
pp. 3199-3208 ◽  
Author(s):  
Maryam Ansari ◽  
S. Mohsen Taghavi ◽  
Sadegh Zarei ◽  
Soraya Mehrb-Moghadam ◽  
Hamzeh Mafakheri ◽  
...  
Keyword(s):  
Host Range ◽  
Pseudomonas Syringae ◽  
Leaf Spot ◽  
Phylogenetic Analyses ◽  
Housekeeping Genes ◽  
Pcr Primers ◽  
Phylogenetic Position ◽  
Leaf Spot Disease ◽  
Bacterial Strains ◽  
Alfalfa Leaf

In this study, we provide a polyphasic characterization of 18 Pseudomonas spp. strains associated with alfalfa leaf spot symptoms in Iran. All of the strains were pathogenic on alfalfa, although the aggressiveness and symptomology varied among the strains. All strains but one were pathogenic on broad bean, cucumber, honeydew, and zucchini, whereas only a fraction of the strains were pathogenic on sugar beet, tomato, and wheat. Syringomycin biosynthesis genes (syrB1 and syrP) were detected using the corresponding PCR primers in all of the strains isolated from alfalfa. Phylogenetic analyses using the sequences of four housekeeping genes (gapA, gltA, gyrB, and rpoD) revealed that all of the strains except one (Als34) belong to phylogroup 2b of P. syringae sensu lato, whereas strain Als34 placed within phylogroup 1 close to the type strain of P. syringae pv. apii. Among the phylogroup 2b strains, nine strains were phylogenetically close to the P. syringae pv. aptata clade, whereas the remainder were scattered among P. syringae pv. atrofaciens and P. syringae pv. syringae strains. Pathogenicity and host range assays of the bacterial strains evaluated in this study on a set of taxonomically diverse plant species did not allow us to assign a “pathovar” status to the alfalfa strains. However, these results provide novel insight into the host range and phylogenetic position of the alfalfa-pathogenic members of P. syringae sensu lato, and they reveal that phenotypically and genotypically heterogeneous strains of the pathogen cause bacterial leaf spot of alfalfa.

Genetics of symbiosis and nitrogen fixation in legumes

1969 ◽  
Vol 172 (1029) ◽  
pp. 417-437 ◽  
Keyword(s):  
Nitrogen Fixation ◽  
Bacterial Strain ◽  
Host Plants ◽  
Strain Differences ◽  
Homogeneous Material ◽  
Developmental Sequence ◽  
Bacterial Strains ◽  
Nodule Bacteria ◽  
Microbial Genetics ◽  
Nodular Tissue

Soon after the isolation of nodule bacteria in 1888, differences were recognized in the ability of bacterial strains to form nodules on particular host plants and in the nitrogen-fixing ability of the nodules so formed. These and other symbiotic heterogeneities were attributed, sometimes correctly, to bacterial strain differences, not then thought to be open to formal genetic analysis. The realization that the host plant was an essential component of this variability came only gradually, stimulated by observations of host varietal differences and by the demand for reliable and homogeneous material for experimental work. Only within the last two decades has host variability been studied by plant breeding, and bacterial strain differences by some of the methods of microbial genetics. This review, except for a brief reference to earlier work of some historic interest, will consider only genetic problems open to investigation by these methods. The developmental sequence in all legume nodules is broadly similar. The initial infection phases are followed by the induction of the nodule, the invasion of part of the nodular tissue and culminate in bacteroid formation and nitrogen fixation; the genetics of symbiosis will be considered in this context.

scholarly journals Use of multi-locus sequencing typing as identification method for the food-borne pathogen Listeria monocytogenes: a review

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Sonia Lamon ◽  
Domenico Meloni ◽  
Simonetta Gianna Consolati ◽  
Anna Mureddu ◽  
Rina Mazzette
Keyword(s):  
Listeria Monocytogenes ◽  
Detection Methods ◽  
Causative Organism ◽  
Intracellular Pathogen ◽  
Bacterial Strains ◽  
New Approach ◽  
Food Borne ◽  
Global Epidemiology ◽  
Selection Of

<em>Listeria monocytogenes</em> is an ubiquitous, intracellular pathogen which has been implicated within the past decade as the causative organism in several outbreaks of foodborne diseases. In this review, a new approach to molecular typing primarily designed for global epidemiology has been described: multi-<em>locus</em> sequencing typing (MLST). This approach is novel, in that it uses data that allow the unambiguous characterization of bacterial strains via the Internet. Our aim is to present the currently available selection of references on <em>L. monocytogenes</em> MLST detection methods and to discuss its use as <em>gold</em> <em>standard</em> to <em>L. monocytogenes</em> subtyping method.

scholarly journals Optimizing the Management of Cadmium Bioremediation Capacity of Metal-Resistant Pseudomonas sp. Strain Al-Dhabi-126 Isolated from the Industrial City of Saudi Arabian Environment

2019 ◽  
Vol 16 (23) ◽  
pp. 4788 ◽  
Author(s):  
Naif Abdullah Al-Dhabi ◽  
Galal Ali Esmail ◽  
Abdul-Kareem Mohammed Ghilan ◽  
Mariadhas Valan Arasu
Keyword(s):  
Bacterial Strain ◽  
Cadmium Toxicity ◽  
Industrial Effluents ◽  
Pseudomonas Sp ◽  
Bacterial Strains ◽  
16S Rdna Gene ◽  
Sequence Characterization ◽  
Industrial City ◽  
Toxic Pollutant ◽  
Cd Removal

In this study, 23 bacterial strains were isolated from a Cadmium (Cd) contaminated soil in the industrial city, Riyadh of Saudi Arabia. Among these isolates six strains were found to withstand cadmium contamination and grow well. From the six isolates Pseudomonas sp. strain Al-Dhabi-122–127 were found to resist cadmium toxicity to a higher level. The isolates were subjected to biochemical and 16S rDNA gene sequence characterization to confirm their identification. The bacterial strain Al-Dhabi-124 showed 1.5 times higher Cd-degrading activity than Al-Dhabi-122 and Al-Dhabi-123, and Al-Dhabi-126 exhibited 3.5 times higher Cd-degrading activity, higher than the other strains. An atomic absorption spectrophotometer study showed that the strain Al-Dhabi-126 absorbed Cd, and that the bacterial strain Al-Dhabi-126 was found to tolerate cadmium level up to 2100 µg/mL. The bacterial strain Al-Dhabi-126 showed a maximum Cd removal efficacy at pH between 6.0 and 8.0. The efficacy decreased sharply after an increase in pH (9.0). An optimum temperature of 50 °C and pH 6.0 were found to be effective for the Cd removal process by the isolate. The study indicated that the bacterial strain Al-Dhabi-126 can be used effectively for the bioremediation of heavy metals like cadmium, a major toxic pollutant in industrial effluents.

Gut microbiota in a host–brood parasite system: insights from common cuckoos raised by two warbler species

2020 ◽  
Vol 96 (9) ◽  
Author(s):  
Lucie Schmiedová ◽  
Jakub Kreisinger ◽  
Milica Požgayová ◽  
Marcel Honza ◽  
Jean-François Martin ◽  
...  
Keyword(s):  
Environmental Factors ◽  
Gut Microbiota ◽  
Acrocephalus Arundinaceus ◽  
Brood Parasite ◽  
Bacterial Strains ◽  
Factors Affecting ◽  
The Common ◽  
Animal Hosts ◽  
Bacterial Sources ◽  
Selection Of

ABSTRACT An animal's gut microbiota (GM) is shaped by a range of environmental factors affecting the bacterial sources invading the host. At the same time, animal hosts are equipped with intrinsic mechanisms enabling regulation of GM. However, there is limited knowledge on the relative importance of these forces. To assess the significance of host-intrinsic vs environmental factors, we studied GM in nestlings of an obligate brood parasite, the common cuckoo (Cuculus canorus), raised by two foster species, great reed warblers (Acrocephalus arundinaceus) and Eurasian reed warblers (A. scirpaceus), and compared these with GM of the fosterers’ own nestlings. We show that fecal GM varied between cuckoo and warbler nestlings when accounting for the effect of foster/parent species, highlighting the importance of host-intrinsic regulatory mechanisms. In addition to feces, cuckoos also expel a deterrent secretion, which provides protection against olfactory predators. We observed an increased abundance of bacterial genera capable of producing repulsive volatile molecules in the deterrent secretion. Consequently, our results support the hypothesis that microbiota play a role in this antipredator mechanism. Interestingly, fosterer/parent identity affected only cuckoo deterrent secretion and warbler feces microbiota, but not that of cuckoo feces, suggesting a strong selection of bacterial strains in the GM by cuckoo nestlings.

scholarly journals Potential risks of antibiotic resistant bacteria and genes in bioremediation of petroleum hydrocarbon contaminated soils

2020 ◽  
Vol 22 (5) ◽  
pp. 1110-1124 ◽  
Author(s):  
Colin J. Cunningham ◽  
Maria S. Kuyukina ◽  
Irena B. Ivshina ◽  
Alexandr I. Konev ◽  
Tatyana A. Peshkur ◽  
...  
Keyword(s):  
Antibiotic Resistance ◽  
Contaminated Soil ◽  
Contaminated Soils ◽  
Petroleum Hydrocarbon ◽  
Resistant Bacteria ◽  
Careful Selection ◽  
Bacterial Strains ◽  
Antibiotic Resistant ◽  
Potential Risks ◽  
Selection Of

The problems associated with potential risks of antibiotic resistance spreading during bioremediation of oil-contaminated soil are discussed. Careful selection of bacterial strains and pretreatment of organic wastes used as fertilizers are suggested.

scholarly journals Opposite Enantioselectivities of Two Phenotypically and Genotypically Similar Strains of Pseudomonas frederiksbergensis in Bacterial Whole-Cell Sulfoxidation

2005 ◽  
Vol 71 (4) ◽  
pp. 2199-2202 ◽  
Author(s):  
Waldemar Adam ◽  
Frank Heckel ◽  
Chantu R. Saha-Möller ◽  
Marcus Taupp ◽  
Jean-Marie Meyer ◽  
...  
Keyword(s):  
Bacterial Strain ◽  
Genetically Modified Organisms ◽  
Genetically Modified ◽  
Soil Samples ◽  
Bacterial Strains ◽  
Whole Cell ◽  
Organic Sulfides

ABSTRACT Soil samples were screened to select microorganisms with the capability to oxidize organic sulfides into the corresponding sulfoxides with differential enantioselectivities. Several bacterial strains that preferentially produced the S-configured sulfoxide enantiomer were isolated. Surprisingly, one bacterial strain, genotypically and phenotypically characterized as Pseudomonas frederiksbergensis, selectively gave the R enantiomer. The finding that two apparently identical organisms displayed opposite enantioselectivities is novel for non-genetically modified organisms.

scholarly journals Bradyrhizobia isolated from root nodules of Parasponia (Ulmaceae) do not constitute a separate coherent lineage

2006 ◽  
Vol 56 (5) ◽  
pp. 1013-1018 ◽  
Author(s):  
Bénédicte Lafay ◽  
Erika Bullier ◽  
Jeremy J. Burdon
Keyword(s):  
16S Rrna ◽  
Host Range ◽  
Root Nodules ◽  
Phylogenetic Analyses ◽  
Rrna Gene ◽  
Bacterial Strains ◽  
Gene Sequences ◽  
Host Switch ◽  
Cultural Types ◽  
The Relationship

Rhizobial bacteria almost exclusively nodulate members of the families Fabaceae, Mimosaceae and Caesalpiniaceae, but are found on a single non-legume taxon, Parasponia (Ulmaceae). Based on their host-range, their nitrogen-fixing ability and strain competition experiments, bacterial strains isolated from Parasponia were thought to constitute a separate lineage that would account for their exceptional host affinity. This hypothesis was investigated by focusing on four isolates that are representative of the morphological and cultural types of Parasponia-nodulating bradyrhizobia. Their evolutionary relationships with other rhizobia were analysed using 16S rRNA gene sequences and their nodulation properties were explored using the nodA gene as a proxy for host-range specificity. Phylogenetic analyses of the 16S rRNA and nodA gene sequences revealed that bacterial isolates from Parasponia species are embedded among other bradyrhizobia. They did not cluster together in topologies based on the 16S rRNA or nodA gene sequences, but were scattered among other bradyrhizobia belonging to either the Bradyrhizobium japonicum or the Bradyrhizobium elkanii lineages. These data suggest that the ability of some bradyrhizobia to nodulate species of the genus Parasponia does not represent a historical relationship that predates the relationship between rhizobia and legumes, but is probably a more recent host switch for some rhizobia.

scholarly journals Selection of efficient rhizobial symbionts for Cratylia argentea in the cerrado biome

2016 ◽  
Vol 46 (9) ◽  
pp. 1594-1600
Author(s):  
Giovanna Moura Calazans ◽  
Christiane Abreu de Oliveira ◽  
José Carlos Cruz ◽  
Walter José Rodrigues Matrangolo ◽  
Ivanildo Evódio Marriel
Keyword(s):  
Nitrogen Concentration ◽  
Dry Weight ◽  
Forage Production ◽  
Bacterial Strains ◽  
Symbiotic Efficiency ◽  
Nodule Number ◽  
Shoot Dry Weight ◽  
Productive System ◽  
Selection Of ◽  
Rhizobial Isolates

ABSTRACT: Cratylia argentea is a leguminous shrub native to the cerrado, which has great potential for forage production and recovery of degraded areas. This study aimed to isolate, characterize, and select efficient rhizobial strains in symbiosis with Cratylia argentea . Rhizobacteria were isolated from the nodules of 12-month-old plants and cultivated in pots containing cerrado soil. Twenty-five bacterial strains were obtained, which displayed extensive variability with respect to morphological and symbiotic characteristics. Cratylia argentea seeds were planted in pots containing 5kg of cerrado soil and maintained in the greenhouse. The treatments consisted of 25 rhizobial isolates, two controls (without nitrogen and without inoculation), with or without nitrogen fertilization (5mgN·plant-1·week-1), and four replications. Plants were cultivated for 150 days after planting seeds to evaluate nodule number, nodule dry weight, shoot and root dry weight, shoot and root N content, and relative and symbiotic efficiency. Thirteen isolates improved shoot dry weight (up to 65.8%) and shoot nitrogen concentration (up to 76%) compared with those of control treatments. Two isolates, 4 (CR42) and 22 (CR52), conferred higher symbiotic efficiency values of approximately 20%. Therefore, these two rhizobial isolates displayed the highest potential as beneficial inoculants to optimize the symbiotic efficiency for Cratylia and to increase the incorporation of nutrients and biomass into the productive system in the cerrado.

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