• Journal of Microbiology and Biotechnology
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• 제30권9호
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• pp.1355-1366
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• 2020

Sediment bacterial communities are critical to the biogeochemical cycle in river ecosystems, but our understanding of the relationship between sediment bacterial communities and their specific input streams in rivers remains insufficient. In this study, we analyzed the sediment bacterial community structure in a local river receiving discharge of urban domestic sewage by applying Illumina MiSeq high-throughput sequencing. The results showed that the bacterial communities of sediments samples of different pollution types had similar dominant phyla, mainly Proteobacteria, Actinobacteria, Chloroflexi and Firmicutes, but their relative abundances were different. Moreover, there were great differences at the genus level. For example, the genus Bacillus showed statistically significant differences in the hotel site. The clustering of bacterial communities at various sites and the dominant families (i.e., Nocardioidaceae, and Sphingomonadaceae) observed in the residential quarter differed from other sites. This result suggested that environmentally induced species sorting greatly influenced the sediment bacterial community composition. The bacterial co-occurrence patterns showed that the river bacteria had a nonrandom modular structure. Microbial taxonomy from the same module had strong ecological links (such as the nitrogenium cycle and degradation of organic pollutants). Additionally, PICRUSt metabolic inference analysis showed the most important function of river bacterial communities under the influence of different types of domestic sewage was metabolism (e.g., genes related to xenobiotic degradation predominated in residential quarter samples). In general, our results emphasize that the adaptive changes and interactions in the bacterial community structure of river sediment represent responses to different exogenous pollution sources.

• The Plant Pathology Journal
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• 제37권6호
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• pp.662-672
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• 2021

Plant growth-promoting bacteria improve plant growth under abiotic stress conditions. However, their effects on microbial succession in the rhizosphere are poorly understood. In this study, the inoculants of Bacillus mesonae strain H20-5 were administered to tomato plants grown in soils with different salinity levels (EC of 2, 4, and 6 dS/m). The bacterial communities in the bulk and rhizosphere soils were examined 14 days after H20-5 treatment using Illumina MiSeq sequencing of the bacterial 16S rRNA gene. Although the abundance of H20-5 rapidly decreased in the bulk and rhizosphere soils, a shift in the bacterial community was observed following H20-5 treatment. The variation in bacterial communities due to H20-5 treatment was higher in the rhizosphere than in the bulk soils. Additionally, the bacterial species richness and diversity were greater in the H20-5 treated rhizosphere than in the control. The composition and structure of the bacterial communities varied with soil salinity levels, and those in the H20-5 treated rhizosphere soil were clustered. The members of Actinobacteria genera, including Kineosporia, Virgisporangium, Actinoplanes, Gaiella, Blastococcus, and Solirubrobacter, were enriched in the H20-5 treated rhizosphere soils. The microbial co-occurrence network of the bacterial community in the H20-5 treated rhizosphere soils had more modules and keystone taxa compared to the control. These findings revealed that the strain H20-5 induced systemic tolerance in tomato plants and influenced the diversity, composition, structure, and network of bacterial communities. The bacterial community in the H20-5 treated rhizosphere soils also appeared to be relatively stable to soil salinity changes.

• 펄프종이기술
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• 제30권4호
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• pp.35-41
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• 1998

The bacterial cellulose has many unique properties that are potentially and commercially beneficial. In order to make opaque product from this cellulose, filling properties by fillers should be known. This study was performed to investigate the effect of filler addition on physical properties of sheets from bacterial cellulose. The effect of filling on its optical properties was also discussed. The apparent density and internal bonding strength of bacterial cellulose sheet are decreasing with the increase of filler contents. Those adversely affect Young's modulus and physical property of the sheet, but these negative phenomena of the bacterial cellulose sheet by filler addition are not so sensitive compared to substantial decreasing of physical properties of ordinary hardwood KP. This strength decrease would be attributed to the decrease of relative bonding sites among pulp fibers. Concerned to optical properties, the bacterial cellulose sheet shows high increase of brightness and opacity according to filler loading, but no significant changes in porosity up to 17.3% loading because of fine and filamentous structure of bacterial cellulose fibers.

• 한국가금학회:학술대회논문집
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• 한국가금학회 2006년도 제23차 정기총회 및 학술발표회
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• pp.86-87
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• 2006

The hatchery sanitation has a significant impact on chick quality. This study was carried out to investigate the bacterial contamination in the broiler hatchery. The aerosol bacterial contamination was low except for the operating hatcher that the bacterial counts were measured almost over 300 counts/64cm$^{2}$. The bacterial contamination of the facilities and equipments had a similar tendency as compared with the aerosol bacterial contamination. More than six groups of the Salmonella species were isolated almost from the hatcher and the related facilities and equipments. Also, in this study, we compared the effects of four methods of 37% formalin adminstration in hatcher. At hatch, the aerosol bacterial counts in hatcher receiving 37% formalin as constant rate infusion method during hatching were significantly lower than in each hatcher receiving 37% formalin once at transfer and not receiving 37% formalin, respectively(p<0.05).

• Journal of Microbiology and Biotechnology
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• 제23권10호
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• pp.1428-1433
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• 2013

Jeotgal fermentation is dependent upon a diverse microbial community, although a detailed understanding of its microbial composition is limited to a relatively small number of jeotgal. Pyrosequencing-based bacterial community analysis was performed in fermented squid, ojingeo jeotgal. Leuconostoc was identified as the predominant bacterial genus, with Bacillus and Staphylococcus also accounting for a large proportion of the bacterial community. Phylogenetic analysis with 16S rRNA genes of Leuconostoc type species indicated that L. citreum- and L. holzapfelii-like strains could be the major Leuconostoc strains in jeotgal. High concentrations of NaCl were thought to be an important factor determining the makeup of the bacterial community in the fermented squid; however, a genomic survey with osmotic stress-related genes suggests the existence of more complex factors selecting the dominant bacterial species in fermented squid.

• 한국식품저장유통학회지
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• 제12권5호
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• pp.455-459
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• 2005

본 연구에서는 BC를 백설기에 첨가하여 저장 중 품질특성을 조사하였다. 그 결과, bacterial cellulose 0.09%이상 첨가한 백설기가 무첨가구에 비해 저장동안 노화도가 낮게 나타났다. 또한 hardness를 측정한 결과 BC첨가를 첨가한 구간들에서 hardness가 낮게 나타나 노화억제효과가 있었다. 관능검사 결과 거의 모든 평가항목에서 시료들 간의 유의적인 차이가 없었으나, 전반적인 기호도에서 BC를 첨가한 백설기가 더 좋은 것으로 나타났다.

• Journal of Forest and Environmental Science
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• 제34권3호
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• pp.258-261
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• 2018

Drought alters soil microorganisms; however, it is still not clear how soil microbes respond to severe drought conditions. In this study, the responses of soil bacterial community to experimental drought in a coniferous stand were examined. Six $6m{\times}6m$ plots with three replicates of control and drought treatments were delimited. PCR amplification and Illumina sequencing were conducted for cluster analysis of soil bacterial community and species richness and species diversity was analyzed. Along the 393 days of simulated drought from July 2016 to October 2017, soil bacterial species diversity slightly increased whereas species richness decreased in both control and roof plots. Moreover, soil bacterial species richness more decreased in roof plots than in controls. Combining these results, soil bacterial activity might have been altered by simulated drought.

• 한국식물병리학회지
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• 제10권1호
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• pp.68-72
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• 1994

Bacterial canker of kiwifruit recently outbroke throughout the southcoast of Korea, the major production areas of kiwifruit. Some orchards were destroyed because of severe damage by the epidemics of the bacterial canker, especially in Jeju-si and Bukjeju-kun, Jeju and Goheung-kun and Wando-kun, Chonnam. The bacterial canker, which has been occurred in Jeju from the mid 1980s, was first observed in Haenam-kun, Chonnam in 1991. The disease outbroken throughout the southcoast of Korea caused extremely severe damages and the diseased areas are increasing continuously. The possibility that the bacterial canker was introduced from Japan into Jeju is high, although the path of the epidemic is still not clear. And then the bacterial canker may spread from Jeju to Haenam and/or Wando, from which the disease may spread to the southcoast of Chonnam and the westcoast of Kyungnam in Korea.

• BMB Reports
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• 제54권11호
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• pp.541-544
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• 2021

Protein glycosylation is a common post-translational modification found in all living organisms. This modification in bacterial pathogens plays a pivotal role in their infectious processes including pathogenicity, immune evasion, and host-pathogen interactions. Importantly, many key proteins of host immune systems are also glycosylated and bacterial pathogens can notably modulate glycosylation of these host proteins to facilitate pathogenesis through the induction of abnormal host protein activity and abundance. In recent years, interest in studying the regulation of host protein glycosylation caused by bacterial pathogens is increasing to fully understand bacterial pathogenesis. In this review, we focus on how bacterial pathogens regulate remodeling of host glycoproteins during infections to promote the pathogenesis.

• Natural Product Sciences
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• 제5권1호
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• pp.7-11
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• 1999

A mixture of several bacterial metabolites $(Sterodin{\circledR})$ was used to study its effect on major immunocytes, in vivo and in vitro. This mixture of bacterial metabolites increased number of macrophages and neutrophils and their phagocytic activity in experimental animals for a transient period. BSA induced antibody production was found to be higher in the drug treated group. These results indicated that the bacterial metabolites probably acted through non-specific defence mechanism against invading organisms and the chance of reinfection was reduced.