Bacteria ; genetics ; growth & development ; Biofilms ; Genetic Heterogeneity

Aims: Attention to ice nucleation proteins has increased for more than two decades. Ice nucleation proteins have been utilized for artificial snow-making known as Snowmax™, cryopreservation of tissues and cells, and cloud condensation nuclei. There is a direct relationship between bacterial growth and ice nucleation activity. Therefore, the optimization of the culture medium seems necessary. Methodology and results: The effect of different carbon and nitrogen sources on the growth of a new native Pseudomonas sp. IRL.INP1 was evaluated by using fractional factorial design, the path of the steepest ascent experiment and central composite design. Ice nucleation activity, biomass and whole-cell protein were identified afterward. The model predicted by response surface methodology indicated that the maximum bacterial growth was observed when sucrose, ammonium sulfate [(NH4)2SO4] and manganese (II) (Mn2+) were utilized at 12.46 g/L, 321.97 mg/L and 938.09 µM, respectively. Also, 1.10 g/L biomass and 0.85 µg/µL whole-cell proteins were gained, and the isolate showed ice nucleation activity 31 sec sooner after optimization. Conclusion, significance and impact of study Ice nucleation proteins are growth-dependent and the growth condition optimization leads to higher bacterial cells growth. Therefore, best bacterial growth was obtained when proper carbon and nitrogen sources were used, and ice nucleation activity was observed in shorter time. This is the first study concerning ice nucleation activity optimization using different carbon and nitrogen sources.
Gram-Negative Bacteria--growth & ; development ; Pseudomonas

Aims: The purpose of this research was to explore the composition and genomic functions of bacterial community inhabiting the rhizosphere of Mimosa pudica, which were naturally growing on tailing and non-tailing soils of an ex-tin mining area. Methodology and results: DNA were extracted from rhizosphere soils and PCR targeting the hypervariable region V3-V4 was carried out by Illumina 16S metagenomic library. Libraries were sequenced using Illumina MiSeq. The Operational Taxonomic Units (OTUs) were assigned to 23 bacterial phyla, 72 classes, 165 orders, 248 families and 357 genera. The most represented and dominant phylum was Proteobacteria, with an average abundance value of 41.2%. The most represented genera included Paraburkholderia, Bradyrhizobium, Bacillus, Candidatus, Acidothermus, Acidibacter and Nitrospira. Non-tailing soils had more number and richness of species while the tailings had more diversity of species. The metagenomes accommodate suspected genes for heavy metal tolerance of microbes (As, Cr, Co, Zn, Ni, Cu, Cd, Fe and Hg) and microbial plant-growth-promoting traits for hyperaccumulator plants (synthesis of indole acetic acid (IAA), siderophore and 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase; solubilization of phosphate and potassium and nitrogen fixation). Conclusion, significance and impact of study Bacteria and predicted genes discovered could be part of major factors influencing growth of M. pudica in heavy metal-contaminated soils. The study provides the first report and a basis into the bacterial community associated with M. pudica in ex-tin mining soils from the studied geographical location. The findings also provide fundamental knowledge on phytoremediation potential of heavy metal contaminated soils involving indigenous beneficial microbial populations.
Bacteria ; Rhizosphere ; Mimosa ; Plant Growth Regulators

The clinical bacteriology laboratory has to be prepared to isolate and identify anaerobes as the implication of anaerobes in clinical infections is increasing. Although many types of thioglycollate media have been widely used for the enrichment growth of anerobes, different types are known to have different growth supporting ability. GAM is a recently developed medium, which is said to support a good growth of anaerobes. This study was made to compare GAM and the commonly used thioglycollate medium. It was found that BTM was superior to FTM, but GAM was showing the heaviest growth after a short incubation time. Hemoglobin powder added to FTM or BTM greatly improved growth of Bacteroides without impairing the clarity of the media. Supplementation of FTM with 1/4 strength each of BHI and TSB, and 1000 mg of hemoglobin per liter of medium improved growth of anaerobes. Among all of the tested media, GAM gave the best results for the cultivation of anaerobes including Bacteroides and Fusobacterium.
Anaerobiosis ; Bacteria/growth & development* ; Comparative Study ; Culture Media* ; Hemoglobins ; Thioglycolates*

Bacteria ; classification ; growth & development ; Candida ; growth & development ; Humans ; Infant ; Infant, Newborn ; Mouth ; microbiology

Ginsenosides are the main active components of medicinal herbs including Panax ginseng and Panax quinquefolium, which have potent effects of anti-tumor, anti-inflammatory, antioxidant and apoptosis inhibition. But the low content of ginsenosides limits its development and usage. At present, how to improve the production of ginsenosides by biological technology has been a new research focus. Some advances in the biosynthesis of ginsenosides by tissue culture and biotransformation have been made in recent years. So far at least twenty genes related to the biosynthesis of ginsenosides from Panax genus plants have been cloned and functionally identified, which has laid a good foundation for the study on the synthetic biology of ginsenosides. This review outlines recent advances in several aspects and is expected to provide a theoretical support to the thorough research of the pathway and regulation of ginsenosides biosynthesis.
Bacteria ; metabolism ; Biotransformation ; Fungi ; metabolism ; Ginsenosides ; biosynthesis ; metabolism ; Panax ; growth & development ; Plants, Medicinal ; growth & development ; Synthetic Biology ; Tissue Culture Techniques

The investigation of the mechanism of biological pattern has been an important topic of life sciences, especially of developmental biology, for a long time. We have established a cellular automata model of biological pattern formation, which defines how to form a biological pattern from individual cells and their behaviors, cell-cell interactions, and cell-environment interactions. In this paper, we use that model to simulate the growth pattern of the bacterial colonies in consideration of the effects of both nutrient and metabolite on the cell's reproduction.
Animals ; Bacteria ; growth & development ; Bacterial Adhesion ; Colony Count, Microbial ; Computer Simulation ; Dictyostelium ; growth & development ; Humans ; Models, Biological

OBJECTIVETo study the characteristics of soil microbial variation during Salvia miltiorrhiza crop rotation.

METHODthe conventional cultivating microbial method was used to study the microbial number and communities structure and soil microbial biomass phosphorus (SMBP) was determined by chloroform vapor extraction method. The data was then analyzed by SPSS software.

RESULTWith the increase of the crop rotation years, the numbers of bacteria and actinomycetes in soil also, but the fungi and SMBP decreased.

CONCLUSIONMicrobial mechanism of crop rotation of the planting S. miltiorrhiza is the regulation of microbial number and bacteria physiological communities, the process rebuilds the soil ecological system balance. Microbial communities in soil need at lest 2 years to get to restore, after planting S. miltiorrhiza, which consisting with traditional planting experience.

Actinobacteria ; isolation & purification ; Bacteria ; isolation & purification ; Plants, Medicinal ; growth & development ; metabolism ; microbiology ; Salvia miltiorrhiza ; growth & development ; metabolism ; microbiology ; Soil Microbiology

OBJECTIVETo study dynamic relation between periodontal pathogens and cariogenic bacteria under analogous oral environment.

METHODSEight periodontopathic and cariogenic bacteria of Porphyromonas gingivalis (Pg), Actinobacillus actinomycetemcomitans (Aa), Fusobacterium nucleatum (Fn), Provotella intermedium (Pi), Streptococcus mutans (Sm), Streptococcus sanguis (Ss), Actinomyces viscosus (Av) and Lactobacillus acidophilus (La) were used. These eight strains were cultured in modified chemostat under analogous oral environment which contained 600 ml modified BM medium supplemented with 2.5 g/L porcine gastric mucin, respectively. After 1, 24, 48 and 96 h, optical sectioning of plaque biofilms on removable and replaceable hydroxyapatite disks was analyzed by the combination of live bacterial Gram fluorescence staining and confocal laser scanning microscopy. Biofilm thickness and reconstruction of the three-dimensional architecture of plaque biofilms were made.

RESULTSBiofilm thickness increased significantly with time (P < 0.001). Biofilms of Aa were thinner than those of Ss and eight-specie biofilms were thicker than those formed by Ss and Aa per time point. Three-dimensional images showed periodontal pathogens mainly occurred in cariogenic bacterial complex or on the biofilm surface.

CONCLUSIONSGram-positive cariogenic species initially predominated in artificial plaque, followed by the increasing proportions of Gram-negative periodontal pathogens. The relation between microecological balance among bacteria and diseases is worthy of further studies.

Bacteria ; growth & development ; Biofilms ; Dental Caries ; microbiology ; Ecology ; Humans ; Microscopy, Confocal ; Periodontal Diseases ; microbiology

To study the enrichment regulation of anammox bacteria during the whole start-up process of anammox reaction, two reactors with addition of carries of Spherical Plastic (SP) and Bamboo Charcoal (BC) and one without carrier (CK) were used to start anammox reaction. Then FISH and q-PCR analyses for the growth of all anammox bacteria were conducted during the operational process. The results indicate that the number of anammox bacteria in all reactors increased with time during the whole start-up process, which was consistent with the removal rate of ammonium and nitrite. On day 123 of stable phase, the percent of anammox cells in the sludge of CK, SP and BC accounted for 23.3%, 32.6% and 43.7%, respectively. The number of anammox bacteria 16S rRNA gene copies was (25.64 +/- 2.76) x 10(7), (47.12 +/- 2.76) x 10(7) and (577.99 +/- 27.25) x 10(7) copies g(-1) VSS in the sludge of CK, SP and BC, respectively. Carrier addition could dramatically increase enrichment of anammox bacteria. BC addition significantly increased the anammox bacteria number in the UASB reactor which resulted in the acceleration of the anammox start-up process. In addition, the max specific growth rate and the minimum doubling time were 0.064 d(-1) and 10.8 d in BC reactor. The max specific growth rate of anammox bacteria in BC reactor was 1.78 times and 1.88 times greater than that in CK and SP reactor, respectively. Therefore, the FISH and q-PCR analyses were suitable for determining the enrichment regulation of anammox bacteria during the start-up time, while a bit of differences in results existed between the two analytical methods due to the difference in analysis targets.
Ammonia ; metabolism ; Bacteria ; growth & development ; metabolism ; Bioreactors ; Industrial Microbiology ; Nitrites ; metabolism ; Oxidation-Reduction ; Sewage ; microbiology