Diversity of Epiphytic Bacterial Communities on Male and Female Porphyra Haitanensis

PurposeEpiphytic bacteria play an important role in macroalgae growth, development, and morphogenesis. However, epiphytic bacterial communities on male and female macroalgae have not been reported. Porphyra haitanensis is one of the main economic macroalgae.In order to explore the similarities and differences of epiphytic bacterial community structure between male and female macroalgae of Porphyra haitanensis.MethodsWe investigated the composition, diversity of epiphytic bacterial communities between male and female Porphyra haitanensis by 16S rDNA high-throughput sequencing.ResultsThe divergences of bacterial community compositions occurred between males and females. Both males and females had their unique bacterial microbiota, such as, Armatimonadetes and Rokubacteria are the unique phyla of male Porphyra haitanensis, Chlamydiae is a unique phylum of female Porphyra haitanensis. The epiphytic bacteria on both male and female Porphyra haitanensis have the similar predictive functions, but they also have their own specific functions, respectively.The specific functions of epiphytic bacteria on female Porphyra haitanensis were sulfite_respiration, nitrogen_fixation, nitrate_ammonification, chlorate_reducers and anoxygenic_photoautotrophy_S_oxidizing. ConclusionsThis study provides a basis for exploring the mechanism of epiphytic bacterial communities on dioecious algae and are of great significance for further understanding the relationships between epiphytic microbial communities and the sex of algae.

The changes in the morpho-functional state of the green alga Ulva intestinalis L. in the Barents Sea under the influence of diesel fuel

The Changes in the morpho-functional state of the green algae Ulva intestinalis L. Intestine of the Barents Sea under the influence of diesel fuel (DF) in doses from 1 to 150 mg/l were studied. It has been shown that the reaction of the algae to the presence of diesel fuel (DF) depends on the toxicant and the duration of exposure. The addition of an petroleum product to the medium in a volume of 1 - 5 mg/l (20-100 MAC) does not lead to the death of algae, however, it causes a decrease in photosynthetic activity and the content of photosynthetic pigments. DF concentrations in the medium from 50 mg/L (1000 MAC) to 150 mg/L (3000 MAC) cause active irreversible changes in algae: disruption of cell structure, suppression of photosynthetic activity, decrease in the concentration of photosynthetic pigments, changes in catalase activity, as well as the number of cultivated epiphytic bacteria. When the content of DF in water is 150 mg/l, various algae die after 3 days of the experiment.

Measurement report: Ice nucleating particles active ≥ −15 °C in free tropospheric air over western Europe

Ice nucleating particles (INP) initiate ice formation in supercooled clouds, typically starting at a few km above ground. However, little is known about the concentration and composition of INP in the lower free troposphere (FT). Here, we analysed INP active at −10 °C (INP−10) and −15 °C (INP−15) collected during FT conditions at the high-altitude observatory Jungfraujoch. We relied on continuous radon measurements to distinguish FT conditions from those influenced by the planetary boundary layer. Median concentrations in the FT were 2.4 INP−10 m−3 and 9.8 INP−15 m−3, with a multiplicative standard deviation of 2.0 and 1.6, respectively. A majority of INP was deactivated after exposure to 60 °C, thus probably originated from certain epiphytic bacteria or fungi. Subsequent heating to 95 °C deactivated another 15 % to 20 % of the initial INP, likely other types of fungal INP that might be associated with soil organic matter or with decaying leaves. Very few INP−10 withstood heating to 95 °C, but on average 20 % of INP−15 in FT samples did so. This percentage doubled during Saharan dust intrusions, which had practically no influence on INP−10. Overall, the results suggest that aerosolised epiphytic microorganisms, or parts thereof, are responsible for the majority of primary ice formation in moderately supercooled clouds above western Europe.

Study on the diversity of epiphytic bacteria on corn and alfalfa using Illumina MiSeq/NovaSeq high-throughput sequencing system

Purpose To investigate the diversity of the epiphytic bacteria on corn (Zea mays) and alfalfa (Medicago sativa) collected in Hengshui City and Xingtai City, Hebei Province, China, and explore crops suitable for natural silage. Methods The Illumina MiSeq/NovaSeq high-throughput sequencing system was used to conduct paired-end sequencing of the community DNA fragments from the surface of corn and alfalfa collected in Hengshui and Xingtai. QIIME2 and R software were used to sort and calculate the number of sequences and taxonomic units for each sample. Thereafter, the alpha and beta diversity indices at of species level were calculated, and the abundance and distribution of taxa were analyzed and compared between samples. Result At phylum level, the dominant groups were Proteobacteria (70%), Firmicutes (13%), Actinobacteria (9%), and Bacteroidetes (7%). Meanwhile, the dominant genera were Pseudomonas (8%), Acinetobacter (4%), Chryseobacterium (3%), and Hymenobacter (1%). Enterobacteriaceae (24%) were the most predominant bacteria in both the corn and alfalfa samples. Alpha diversity analysis and beta diversity indices revealed that the diversity of epiphytic microbial communities was significantly affected by plant species but not by region. The diversity and richness of the epiphytic bacterial community of alfalfa were significantly higher than those of corn. Conclusion This study contributes to the expanding knowledge on the diversity of epiphytic bacteria in corn and alfalfa silage and provides a basis for the selection of raw materials.

Community Structure and Function of Epiphytic Bacteria Associated With Myriophyllum spicatum in Baiyangdian Lake, China

Epiphytic bacteria on the surfaces of submerged macrophytes play important roles in the growth of the host plant, nutrient cycling, and the conversion of pollutants in aquatic systems. A knowledge of the epiphytic bacterial community structure could help us to understand these roles. In this study, the abundance, diversity, and functions of the epiphytic bacterial community of Myriophyllum spicatum collected from Baiyangdian Lake in June, August, and October 2019 were studied using quantitative PCR (qPCR), high-throughput sequencing, and the prediction of functions. An analysis using qPCR showed that the epiphytic bacteria were the most abundant in October and the least abundant in August. High-throughput sequencing revealed that Proteobacteria, Gammaproteobacteria, and Aeromonas were the dominant phylum, class, and genus in all the samples. The common analyses of operational taxonomic units (OTUs), NMDS, and LDA showed that the epiphytic bacterial communities were clustered together based on the seasons. The results of a canonical correlation analysis (CCA) showed that the key water quality index that affected the changes of epiphytic bacterial community of M. spicatum was the total phosphorus (TP). The changes in abundance of Gammaproteobacteria negatively correlated with the TP. Predictive results from FAPROTAX showed that the predominant biogeochemical cycle functions of the epiphytic bacterial community were chemoheterotrophy, nitrate reduction, and fermentation. These results suggest that the epiphytic bacterial community of M. spicatum from Baiyangdian Lake varies substantially with the seasons and environmental conditions.

Isolation and Antibacterial Activity Test of Seagrass Epiphytic Symbiont Bacteria Thalassia hemprichii from Bahowo Waters, North Sulawesi

Seagrass is a higher plant and has the ability to produce bioactive compounds such as antibacterial. Seagrass is also a host to a variety of bacteria. Bacteria that live in the host will produce the same compounds as the host's body. The utilization of symbiotic bacteria with seagrasses as producers of bioactive compounds such as antibacterial can be used as a solution to reduce excessive seagrass uptake in nature. On the other hand, bacteria have the advantage of being fast and easy to grow and can be mass-produced and more economical. This study aims to isolate and test the antibacterial activity of the epiphytic bacteria of seagrass symbionts. Epiphytic bacteria of seagrass symbionts were grown on Nutrient Agar media directly in the field and bacterial isolation was carried out based on the morphological characteristics of the bacterial isolates. The antibacterial activity test was carried out using the disc method with the test bacteria Stapylococcus aureus, Streptococcus mutans, Escherichia coli, Salmonella thypi, and antibiotics as positive controls. The ability of bacteria to produce antibacterial was indicated by the formation of an inhibition zone around the paper disc containing the epiphytic bacteria of the seagrass symbiont T. hemprichii. A total of 3 isolates of epiphytic bacteria were isolated from T. hemprichii seagrass from Bahowo Waters, Tongkaina Village, Bunaken District, these isolates are namely Epifit 1, Epiphyte 2, and Epiphyte 3. Epiphyte 2 isolate had antibacterial activity against S. mutans, S. aureus, and S. thypi test bacteria, Epiphyte 3 isolate had antibacterial activity against S. mutans, and S. thypi test bacteria.Key words: Bacteria; Antibacterial; T. hemprichii; symbionts; BahowoAbstrakLamun merupakan tumbuhan tingkat tinggi dan memiliki kemampuan menghasilkan senyawa bioaktif seperti antibakteri. Lamun juga merupakan tempat hidup atau inang dari berbagai bakteri. Bakteri yang hidup pada inang akan menghasilkan senyawa yang sama dengan tubuh inangnya. Pemanfaatan bakteri yang bersimbiosis dengan lamun sebagai produsen senyawa bioaktif seperti antibakteri dapat dijadikan sebagai solusi dalam mengurangi pengambilan lamun yang berlebihan di alam. Dilain pihak, bakteri memiliki keunggulan karena pertumbuhan bakteri yang cepat dan mudah tumbuh, dapat diproduksi secara massal dan lebih ekonomis. Penelitian ini bertujuan untuk mengisolasi dan menguji aktivitas antibakteri dari bakteri epifit simbion lamun T. hemprichii dari Perairan Bahowo. Bakteri epifit simbion lamun ditumbuhkan pada media NA secara langsung di lapangan dan isolasi bakteri dilaksanakan berdasarkan karateristik morfologi isolat bakteri. Uji aktivitas bakteri dilakukan menggunakan metode cakram dengan bakteri uji S. aureus, S. mutans, E. coli, dan S. thypi dan antibiotik sebagai kontrol positif. Kemampuan bakteri menghasilkan antibakteri ditandai dengan terbentuknya zona hambat disekitar kertas cakram yang mengandung bakkteri epifit simbion lamun T. hemprichii. Sebanyak 3 isolat bakteri epifit berhasil diisolasi pada lamun T. hemprichii dari Perairan Bahowo, Kelurahan Tongkaina, Kecamatan Bunaken yaitu Epifit 1, Epifit 2, dan Epifit 3. Isolat epifit 3 memiliki aktivitas antibakteri terhadap bakteri uji S. thypi, isolat Epifit 2 terhadap bakteri uji S. mutans, S. aureus, dan S. thypi, isolat Epifit 3 terhadap bakteri uji S. mutans, dan S. thypi.Kata kunci: Bakteri; Antibakteri; T. hemprichii; Simbion; Bahowo

Study on the Diversity of Epiphytic Bacteria on Corn and Alfalfa using Illumina MiSeq/NovaSeq High-throughput Sequencing System

PurposeTo investigate the diversity of the epiphytic bacteria on corn and alfalfa collected in Hengshui city and Xingtai city, hebei province, China.MethodsIllumina MiSeq/NovaSeq High-throughput sequencing systerm was used to conduct Paired-end sequencing of community DNA fragments from surface of corn and alfalfa in Hengshui and Xingtai. QIIME2 and R language were employed to sort and calculate the number of sequences and taxonomic units for each sample. Thereafter, the abundance, distribution, alpha diversity index of species, beta diversity and the differences of abundance among the samples were analyzed. ResultAt phylum level, the advantage bacterium group are Proteobacteria (70%), Firmicutes (13%), Actinobacteria (9%) and Bacteroidetes (7%). The dominant genera are Pseudomonas (8%), Acinetobacter (4%), Chryseobacterium (3%), Hymenobacter (1%). Enterobacteriaceae (24%) are the most predominant bacteria on both corn and alfalfa samples. Alpha diversity analysis and beta diversity analysis showed that the diversity of epiphytic microbial community was significantly affected by plant species, but not by region. The diversity and richness of epiphytic bacterial community of alfalfa were significantly higher than that of corn, yet corn had more LAB than alfalfa samples. ConclusionThis study contributes to expanding our understanding of the diversity of epiphytic microorganisms in corn and alfalfa silage and provide a basis for the selection of raw materials.