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Journal of Food Protection May 1981Selected biochemical and microbial changes in Penaeus shrimp inoculated with Planococcus citreus were examined to determine the potential of this organism to contribute...
Selected biochemical and microbial changes in Penaeus shrimp inoculated with Planococcus citreus were examined to determine the potential of this organism to contribute to spoilage of shrimp. Biochemical and microbial studies were conducted following storage of Penaeus shrimp at 5 C for 0, 4, 8, 12 and 16 days. Three samples, a control (raw shrimp), an irradiated (600 Krad) control and an irradiated (600 Krad) sample inoculated with P. citreus , were analyzed for changes in aerobic plate count, pH, total volatile nitrogen/amino acid nitrogen (TVN/AA-N) ratio, trimethyl amine-nitrogen (TMN) and total extractable protein (TEP). P. citreus counts increased in the inoculated shrimp from 3.0 × 10 bacteria/gram at 0 day to 1.5 × 10 bacteria/gram at the 16th day. By the 16th day of storage, the pH of the inoculated shrimp was significantly higher than the pH of the other samples. P. citreus inoculated onto irradiated shrimp was able to produce a TVN/AA-N ratio of 1.3 by the 10th day of storage, about the same time as that developed by the natural flora on raw shrimp. The increase in TMN content of the control (raw shrimp) and the inoculated sample were not significantly different. P. citreus was also able to bring about a significant decrease in the percent TEP of shrimp during storage. These changes indicate the capabilities of P. citreus in lowering the overall quality of Penaeus shrimp.
PubMed: 30836502
DOI: 10.4315/0362-028X-44.5.359 -
Standards in Genomic Sciences 2018Y42, isolated from the petroleum-contaminated soil of the Qaidam Basin, can use crude oil as its sole source of carbon and energy at 20 °C. The genome of strain Y42...
Y42, isolated from the petroleum-contaminated soil of the Qaidam Basin, can use crude oil as its sole source of carbon and energy at 20 °C. The genome of strain Y42 has been sequenced to provide information on its properties. Genomic analysis shows that the genome of strain Y42 contains one circular DNA chromosome with a size of 3,718,896 bp and a GC content of 48.8%, and three plasmids (329,482; 89,073; and 12,282 bp). Although the strain Y42 did not show a remarkably higher ability in degrading crude oil than other oil-degrading bacteria, the existence of strain Y42 played a significant role to reducing the overall environmental impact as an indigenous oil-degrading bacterium. In addition, genome annotation revealed that strain Y42 has many genes responsible for hydrocarbon degradation. Structural features of the genomes might provide a competitive edge for strain Y42 to survive in oil-polluted environments and be worthy of further study in oil degradation for the recovery of crude oil-polluted environments.
PubMed: 30338026
DOI: 10.1186/s40793-018-0328-9 -
IET Nanobiotechnology Aug 2018Here, extracellular synthesis of silver nanoparticles (AgNPs) was carried out by strain BGCC-51 isolated from dye industry effluent soil. The microbes were isolated,...
Here, extracellular synthesis of silver nanoparticles (AgNPs) was carried out by strain BGCC-51 isolated from dye industry effluent soil. The microbes were isolated, screened, and characterised by molecular analysis (accession number KX776160). The optimisation of synthesis of AgNPs to determine the optimum substrate level (1-5 mM), pH (5-9), and temperature (25-55°C) were further carried out. strain BGCC-51 gave best yield of AgNPs at substrate concentration 5 mM, pH 8, and at 35°C. Synthesised AgNPs were characterised by scanning electron microscope and high-resolution transmission electron microscope. The size of synthesised AgNPs was in the range of 20-40 nm having spherical morphology. The AgNPs were found to show antimicrobial activity against bacteria such as (ATCC 25922), (ATCC 27853), and (ATCC 29213).
Topics: Biotechnology; Coloring Agents; Extracellular Space; Metal Nanoparticles; Oxidation-Reduction; Planococcaceae; Silver; Soil Microbiology; Textile Industry
PubMed: 30095422
DOI: 10.1049/iet-nbt.2017.0251 -
Applied and Environmental Microbiology Sep 1997Acetobacter diazotrophicus was isolated from coffee plant tissues and from rhizosphere soils. Isolation frequencies ranged from 15 to 40% and were dependent on soil pH....
Acetobacter diazotrophicus was isolated from coffee plant tissues and from rhizosphere soils. Isolation frequencies ranged from 15 to 40% and were dependent on soil pH. Attempts to isolate this bacterial species from coffee fruit, from inside vesicular-arbuscular mycorrhizal fungi spores, or from mealybugs (Planococcus citri) associated with coffee plants were not successful. Other acid-producing diazotrophic bacteria were recovered with frequencies of 20% from the coffee rhizosphere. These N2-fixing isolates had some features in common with the genus Acetobacter but should not be assigned to the species Acetobacter diazotrophicus because they differed from A. diazotrophicus in morphological and biochemical traits and were largely divergent in electrophoretic mobility patterns of metabolic enzymes at coefficients of genetic distance as high as 0.950. In addition, these N2-fixing acetobacteria differed in the small-subunit rRNA restriction fragment length polymorphism patterns obtained with EcoRI, and they exhibited very low DNA-DNA homology levels, ranging from 11 to 15% with the A. diazotrophicus reference strain PAI 5T. Thus, some of the diazotrophic acetobacteria recovered from the rhizosphere of coffee plants may be regarded as N2-fixing species of the genus Acetobacter other than A. diazotrophicus. Endophytic diazotrophic bacteria may be more prevalent than previously thought, and perhaps there are many more potentially beneficial N2-fixing bacteria which can be isolated from other agronomically important crops.
Topics: Acetobacter; Coffee; DNA, Bacterial; DNA, Ribosomal; Molecular Sequence Data; Nitrogen Fixation; Polymorphism, Restriction Fragment Length; Soil Microbiology; Symbiosis
PubMed: 9293018
DOI: 10.1128/aem.63.9.3676-3683.1997 -
PloS One 2013Many insects maintain intracellular mutualistic symbiosis with a wide range of bacteria which are considered essential for their survival (primary or P-endosymbiont) and...
Many insects maintain intracellular mutualistic symbiosis with a wide range of bacteria which are considered essential for their survival (primary or P-endosymbiont) and typically suffer drastic genome degradation. Progressive loss of P-endosymbiont metabolic capabilities could lead to the recruitment of co-existent facultative endosymbiont (secondary or S-endosymbiont), thus adding more complexity to the symbiotic system. Planococcus citri, among other mealybug species, harbors an unconventional nested endosymbiotic system where every Tremblaya princeps cell (β-proteobacterium) harbors many Moranella endobia cells (γ-proteobacterium). In this system, T. princeps possess one of the smallest prokaryote genome known so far. This extreme genome reduction suggests the supply of many metabolites and essential gene products by M. endobia. Although sporadic cell lysis is plausible, the bacterial participation on the regulation of the predicted molecular exchange (at least to some extent) cannot be excluded. Although the comprehensive analysis of the protein translocation ability of M. endobia PCVAL rules out the existence of specific mechanisms for the exportation of proteins from M. endobia to T. princeps, immunolocation of two M. endobia proteins points towards a non-massive but controlled protein provision. We propose a sporadic pattern for the predicted protein exportation events, which could be putatively controlled by the host and/or mediated by local osmotic stress.
Topics: Animals; Bacterial Proteins; Betaproteobacteria; DNA, Bacterial; Gammaproteobacteria; Gene Expression Regulation, Bacterial; Genome Size; Genome, Bacterial; Molecular Sequence Annotation; Planococcus Insect; Protein Transport; Sequence Analysis, DNA; Symbiosis
PubMed: 24204799
DOI: 10.1371/journal.pone.0077307