Jong-Pyo Kang

Cardamom fruits as a green resource for facile synthesis of gold and silver nanoparticles and their biological applications

Abstract Gold (FA-AuNps) and silver (FA-AgNps) nanoparticles were synthesized at room temperature by aqueous extract of dried fruits of Amomum villosum, also known as Fructus Amomi (cardamom), in order to confer antioxidant, catalytic, antimicrobial activities and treatment effect against breast cancer cells. Fruit extracts served as both reducing agents and stabilizers in lieu of chemical agents. Ultra-violet visible (UV-Vis) spectroscopy, field emission transmission electron microscopy (FE-TEM), energy-dispersive X-ray (EDX) spectroscopy, elemental mapping, X-ray powder diffraction (XRD), selected area electron diffraction (SAED), dynamic light scattering (DLS) and Fourier transform infrared (FTIR) spectroscopy were employed to characterize the biosynthesized nanoparticles. Both FA-AuNps and FA-AgNps exhibited free radical scavenging activity against 2,2-diphenyl-1-picrylhydrzyl (DPPH). Additionally, biosynthesized nanoparticles successfully reduced methylene blue, a well-known redox indicator. FA-AgNps showed zones of inhibition against pathogenic Staphylococcus aureus and Escherichia coli. Finally, the biological activities and cytotoxicity of nanoparticles were subsequently investigated in vitro. FA-AuNps demonstrated a potential cytotoxic agent against breast cancer cells as evaluated by MTT assay. The study highlights a rapid synthesis of FA-AuNps and FA-AgNps by dried Fructus Amomi aqueous extract and evaluates their potential biological applications on medical platforms. Graphical Abstract

Biological synthesis of gold and silver chloride nanoparticles by Glycyrrhiza uralensis and in vitro applications

Abstract The current study highlights the rapid biosynthesis of gold nanoparticles (Gu–AuNps) and silver chloride nanoparticles (Gu–AgClNps) by aqueous root extract of Glycyrrhiza uralensis, a medicinal plant. G. uralensis has been reported for anticancer and hepatoprotective effects. The reduction of chloroauric acid and silver nitrate by the Glycyrrhiza root extract prompted the formation of Gu–AuNps and Gu–AgClNps within 4 and 40 min at 80 °C, respectively. The complete reaction did not require supplemental reducing and stabilizing agents, which demonstrated green synthesis. Field emission transmission electron microscopy (FE-TEM) revealed the spherical shape of Gu–AuNps and Gu–AgClNps. X-ray diffraction (XRD) showed face-centred cubic structure of Gu–AuNps and Gu–AgClNps with average crystallite size 12.25 nm and 8.01 nm, respectively. The biosynthesized Gu–AgClNps served as competent antimicrobial agent against Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa and Salmonella enterica. Additionally, Gu–AuNps and Gu–AgClNps were analyzed for their catalytic ability to reduce methylene blue as model test pollutant. Likewise, both nanoparticles possessed free radical scavenging activity against 2,2-diphenyl-1-picrylhydrzyl (DPPH). Moreover, in vitro cytotoxicity in murine macrophage (RAW264.7) and human breast cancer (MCF7) cells were evaluated. Thus, the study proposes a green synthesis of Gu–AuNps and Gu–AgClNps by G. uralensis extract and in vitro biological applications.

In vitro anti-inflammatory activity of spherical silver nanoparticles and monodisperse hexagonal gold nanoparticles by fruit extract of Prunus serrulata: a green synthetic approach

Abstract Recently, green metal nanoparticles have received global attention owing to their economical synthesis, biocompatible nature, widespread biomedical and environmental applications. Current study demonstrates a sustainable approach for the green synthesis of silver nanoparticles (P-AgNPs) and gold nanoparticles (P-AuNPs) from P. serrulata fresh fruit extract. The silver and gold nanoparticles were synthesized in a very rapid, efficient and facile manner, within 50 min and 30 s at 80 °C, respectively. The nanoparticles were characterized by using visual observation, UV–Vis, FE-TEM, EDX, elemental mapping, FT-IR, XRD and DLS, which confirmed the formation of monodispersed, crystalline and stable nanoparticles. Further, we explored these nanoparticles for anti-inflammatory activity through inhibition of downstream NF-κB activation in macrophages (RAW264.7). We demonstrated that the nanoparticles reduced expression of inflammatory mediators such as nitric oxide (NO), prostaglandin E2 (PEG2), inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) was attenuated in lipopolysaccharide (LPS)-induced RAW264.7 cells. Furthermore, nanoparticles significantly suppressed LPS-induced activation of NF-κB signalling pathway via p38 MAPK in RAW 264.7 cells. To the best of our knowledge, this is the first report on the efficient green synthesis of P-AgNPs and P-AuNPs using P. serrulata fresh fruit extract and its in vitro anti-inflammatory effects. Collectively, our results suggest that P. serrulata fresh fruit extract is a green resource for the eco-friendly synthesis of P-AgNPs and P-AuNPs, which further can be utilized as a novel therapeutic agent for prevention and cure of inflammation due to their biocompatible nature.

Humibacter ginsengiterrae sp. nov., and Humibacter ginsengisoli sp. nov., isolated from soil of a ginseng field

Two novel Gram-staining-positive bacteria, designated DCY60T and DCY90T, were isolated from soil of a ginseng field in the Republic of Korea. 16S rRNA gene sequence comparisons showed the two novel strains were closely related to members of the genus Humibacter with greatest similarity to Humibacter antri KCTC 33009T (98.8 and 98.4% for DCY60T and DCY90T, respectively). The predominant menaquinones present were MK-11 and MK-12. The major fatty acids were anteiso-C17 : 0 and summed feature 8 containing C18 : 1ω7c and/or C18 : 1ω6c. The DNA G+C contents of strains DCY60T and DCY90T were 62.8 and 66.8 mol%, respectively. The peptidoglycan of both strains contained the amino acids ornithine, 2,4-diaminobutyric acid, alanine, glutamic acid and glycine. The cell-wall sugars of strain DCY60T comprised glucose, galactose, rhamnose and xylose, while strain DCY90T contained glucose, galactose, rhamnose and ribose. The major polar lipids of both strains were phosphatidylglycerol, an unidentified glycolipid, and an unknown phospholipid. On the basis of the phenotypic analysis strains DCY60T and DCY90T represent novel species of the genus Humibacter, for which names Humibacter ginsengiterrae sp. nov. (type strain DCY60T = KCTC 33520T = JCM 30079T) and Humibacter ginsengisoli sp. nov. (type strain DCY90T = KCTC 33521T = JCM 30080T) are proposed.

Microbacterium rhizomatis sp. nov., a β-glucosidase-producing bacterium isolated from rhizome of Korean mountain ginseng.

A novel Gram-staining-positive, rod-shaped bacterium, designated DCY100(T), was isolated from rhizome of mountain ginseng root in Hwacheon mountain, Gangwon province, Republic of Korea. The 16S rRNA gene sequence analysis showed that strain DCY100(T) belonged to the genus Microbacterium and was most closely related to Microbacterium ginsengisoli KCTC 19189(T) (97.9%), Microbacterium lacus JCM 15575(T) (97.2%) and Microbacterium invictum DSM 19600(T) (97.1%). The major menaquinones were MK-11 and MK-12. The major polar lipids were found to be diphosphatidylglycerol, phosphatidylglycerol and one unidentified glycolipid. The major fatty acids (>10.0%) were anteiso-C15 : 0, anteiso-C17 : 0 and iso-C16 : 0. The cell-wall peptidoglycan contained the amino acids ornithine, alanine, glutamic acid and glycine; whole-cell sugars consisted of glucose, galactose, rhamnose and ribose. The DNA G+C content was 63.6 ± 0.7 mol%. The DNA-DNA hybridization relatedness values between strain DCY100(T) and Microbacterium ginsengisoli KCTC 19189(T), Microbacterium lacus JCM 15575(T) and Microbacterium invictum DSM 19600(T) were 36.2 ± 0.4, 22.0 ± 3.0 and 15.3 ± 1.8%, respectively. On the basis of phenotypic, chemotaxonomic and genotypic analyses, the isolate is classified as a representative of a novel species in the genus Microbacterium, for which the name Microbacterium rhizomatis DCY100(T) is proposed. The type strain is DCY100(T) ( = KCTC 39529(T) = JCM 30598(T)).

Bacterial Diversity and Community Structure in Korean Ginseng Field Soil Are Shifted by Cultivation Time.

Traditional molecular methods have been used to examine bacterial communities in ginseng-cultivated soil samples in a time-dependent manner. Despite these efforts, our understanding of the bacterial community is still inadequate. Therefore, in this study, a high-throughput sequencing approach was employed to investigate bacterial diversity in various ginseng field soil samples over cultivation times of 2, 4, and 6 years in the first and second rounds of cultivation. We used non-cultivated soil samples to perform a comparative study. Moreover, this study assessed changes in the bacterial community associated with soil depth and the health state of the ginseng. Bacterial richness decreased through years of cultivation. This study detected differences in relative abundance of bacterial populations between the first and second rounds of cultivation, years of cultivation, and health states of ginseng. These bacterial populations were mainly distributed in the classes Acidobacteria, Alphaproteobacteria, Deltaproteobacteria, Gammaproteobacteria, and Sphingobacteria. In addition, we found that pH, available phosphorus, and exchangeable Ca+ seemed to have high correlations with bacterial class in ginseng cultivated soil.

Paenibacillus panaciterrae sp. nov., isolated from ginseng cultivated soil.

A novel bacterium, designated DCY95T, was isolated from ginseng-cultivated soil in Quang Nam province, Vietnam. On the basis of 16S rRNA and gyrB gene sequence analysis, this isolate was assigned to the genus Paenibacillus and found to be closely related to Paenibacillus sacheonensis SY01T (97.1 % 16S rRNA gene sequence similarity) and Paenibacillus taihuensis THMBG22T (96.4 %). The partial gyrB gene of DCY95T possessed 69.6-83.9 % sequence identity to those of other members of the genus Paenibacillus. Strain DCY95T was Gram-reaction-negative, catalase-negative, oxidase-positive, strictly aerobic, rod-shaped and motile by means of peritrichous flagella. Ellipsoidal free spores or subterminal endospores were produced in sporangia. MK-7 was the diagnostic menaquinone. The cell-wall peptidoglycan contained meso-diamonopimelic acid as the diamino acid. Whole-cell sugars comprised ribose, mannose and glucose. The major cellular fatty acids were anteiso-C15 : 0, iso-C16 : 0 and C16 : 0. The major polar lipids were phosphatidylethanolamine, phosphatidylglycerol, three unidentified aminophospholipids, and two unidentified phospholipids. The genomic DNA G+C content was 60.7 ± 0.9 mol%. Phenotypic and chemotaxonomic results placed strain DCY95T within the genus Paenibacillus. However, DNA-DNA relatedness values between strain DCY95T and P. sacheonensis KACC 14895T or P. taihuensis NBRC 108766T were lower than 36 %. The low DNA relatedness data in combination with phylogenetic and (GTG)5-PCR analyses, as well as biochemical tests, indicated that strain DCY95T could not be assigned to any recognized species. In conclusion, the results in this study support the classification of strain DCY95T as a representative of a novel species within the genus Paenibacillus, for which the name Paenibacillus panaciterrae is proposed. The type strain is DCY95T ( = KCTC 33581T = DSM 29477T).

Duganella ginsengisoli sp. nov., isolated from ginseng soil.

A Gram-stain-negative, rod-shaped bacterium, designated DCY83T, was isolated from soil of a ginseng field in Gwangju Province, Republic of Korea. Cells were motile by means of flagella. Growth occurred at 4-40 °C (optimum 30 °C), at pH 6-8 (optimum pH 7.0) and with ≤ 0.4 % NaCl. Strain DCY83T was able to produce siderophore and was positive for phosphate solubilization. Indole-3-acetic acid production was 12.9 μg ml- 1 after 3 days in culture. 16S rRNA gene sequence analysis showed that strain DCY83T belonged to the genus Duganella and was related most closely to Duganella sacchari Sac-22T (97.4 % similarity), Duganella zoogloeoides IAM 12670T (97.1 %) and Duganella radicis Sac-41T (97.1 %). The major fatty acids were C16 : 0 and summed feature 3 (containing C16 : 1ω7c and/or C16 : 1ω6c). The major polar lipids were phosphatidylglycerol and phosphatidylethanolamine. The only quinone was ubiquinone 8. The genomic DNA G+C content was 55.3 mol%. DNA-DNA relatedness between strain DCY83T and D. sacchari KCTC 22381T, D. zoogloeoides JCM 20729T and D. radicis KCTC 22382T was 27.7, 22.4 and 35.5 %, respectively. On the basis of the phenotypic and genotypic analysis, DCY83T is classified as representing a novel species in the genus Duganella, for which the name Duganella ginsengisoli sp. nov. is proposed. The type strain is DCY83T ( = KCTC 42409T = JCM 30745T).

Lysobacter panacihumi sp. nov., isolated from ginseng cultivated soil

A Gram-negative, non-motile, aerobic, catalase-, and oxidasepositive bacterial strain, designated DCY117T, was isolated from ginseng cultivated soil in Gochang-gun, Republic of Korea, and was characterized taxonomically using a multifaceted approach. 16S rRNA gene sequence analysis revealed that strain DCY117T showed highest similarity to Lysobacter ruishenii CTN-1T (95.3%). Phylogenetic analysis revealed that closely related relatives of strain DCY117T were L. aestuarii S2-CT (95.1%), L. daejeonensis GH1-9T (95.0%), and L. caeni BUT-8T (94.9%). Diphosphatidylglycerol (DPG), phosphatidylglycerol (PG), and phosphatidylethanolamine (PE) were the major polar lipids of strain DCY117T. The major isoprenoid quinone was Q-8. The major cellular fatty acids of strain DCY117T were iso-C15:0, iso-C16:0, and summed feature 9 (comprising iso-C17:1ω9c and/or 10-methyl-C16:0). Genomic DNA G + C content was 61.8 mol%. On the basis of our findings, strain DCY117T is a novel species in the genus Lysobacter. We propose the name Lysobacter panacihumi sp. nov., and the type strain is DCY117T (= KCTC 62019T = JCM 32168T).

Rhodoferax koreense sp. nov, an obligately aerobic bacterium within the family Comamonadaceae, and emended description of the genus Rhodoferax

Gram-staining-negative, uniflagellated, rod-shaped, designated as DCY110T, was isolated from sludge located in Gangwon province, Republic of Korea. The phylogenetic tree of 16S rRNA gene sequence showed that the strain DCY110T belonged to the genus Rhodoferax with a close similarity to Rhodoferax saidenbachensis DSM 22694T (97.7%), Rhodoferax antarcticus DSM 24876T (97.5%), Rhodoferax ferrireducens DSM 15236T (97.3%), and Rhodoferax fermentans JCM 7819T (96.7%). The predominant isoprenoid quinine was ubiquinone (Q-8). DNA G + C content was 62.8 mol%. The major polar lipids were phosphatidylethanolamine and two unidentified phospholipids. The major fatty acids (> 10%) were C12:0, C16:0, summed feature 3 (which comprised C16:1ω7c and/or C16:1ω6c). The DNA-DNA relatedness values between the strain DCY110T and the closely related relatives used in this study were lower than 70%. Based on the following polyphasic analysis, the strain DCY110T is considered as a novel species of the genus Rhodoferax, for which the name Rhodoferax koreense sp. nov. is proposed. The type strain is DCY-110T (= KCTC 52288T = JCM 31441T).