Elioraea tepida, sp. nov., a Moderately Thermophilic Aerobic Anoxygenic Phototrophic Bacterium Isolated from the Mat Community of an Alkaline Siliceous Hot Spring in Yellowstone National Park, WY, USA

Strain MS-P2T was isolated from microbial mats associated with Mushroom Spring, an alkaline siliceous hot spring in Yellowstone National Park, WY, USA. The isolate grows chemoheterotrophically by oxygen-dependent respiration, and light stimulates photoheterotrophic growth under strictly oxic conditions. Strain MS-P2T synthesizes bacteriochlorophyll a and the carotenoid spirilloxanthin. However, photoautotrophic growth did not occur under oxic or anoxic conditions, suggesting that this strain should be classified as an aerobic anoxygenic phototrophic bacterium. Strain MS-P2T cells are motile, curved rods about 0.5 to 1.0 μm wide and 1.0 to 1.5 μm long. The optimum growth temperature is 45–50 °C, and the optimum pH for growth is circum-neutral (pH 7.0–7.5). Sequence analysis of the 16S rRNA gene revealed that strain MS-P2T is closely related to Elioraea species, members of the class Alphaproteobacteria, with a sequence identity of 96.58 to 98%. The genome of strain MS-P2T is a single circular DNA molecule of 3,367,643 bp with a mol% guanine-plus-cytosine content of 70.6%. Based on phylogenetic, physiological, biochemical, and genomic characteristics, we propose this bacteriochlorophyll a-containing isolate is a new species belonging to the genus Elioraea, with the suggested name Elioraeatepida. The type-strain is strain MS-P2T (= JCM33060T = ATCC TSD-174T).

Pseudodesulfovibrio sediminis sp. nov., a Mesophilic and Neutrophilic Sulfate-reducing Bacterium Isolated From Sediment of a Brackish Lake

A novel mesophilic and neutrophilic sulfate-reducing bacterium, strain SF6T, was isolated from sediment of a brackish lake in Japan. Cells of strain SF6T were motile and rod-shaped with length of 1.2–2.5 μm and width of 0.6–0.9 μm. Growth was observed at 10–37°C with an optimum growth temperature of 28°C. The pH range for growth was 5.8–8.2 with an optimum pH of 7.0. The most predominant fatty acid was anteiso-C15 : 0. Under sulfate-reducing conditions, strain SF6T utilized formate, lactate, ethanol and glucose as growth substrate. Chemolithoautotrophic growth on H2 was also observed. Fermentative growth occurred on pyruvate. As electron acceptor, sulfate, sulfite, thiosulfate and nitrate supported heterotrophic growth of the strain. The complete genome of strain SF6T is composed of a circular chromosome with length of 3.8 Mbp and G + C content of 54 mol%. Analyses of the 16S rRNA gene and whole genome sequence indicated that strain SF6T belongs to the genus Pseudodesulfovibrio but distinct form all existing species in the genus. On the basis of its genomic and phenotypic properties, strain SF6T (= DSM111931T = NBRC 114895T) is proposed as the type strain of a new species, with name of Pseudodesulfovibrio sediminis sp. nov.

Characterization and pathogenicity of Pythium-like species associated with root and collar rot of kiwifruit in Turkey

During the period of June to October in 2018, a widespread decline was observed on kiwifruit vines in the vineyards located in Altınordu, Fatsa, and Perşembe districts of Ordu province. The symptoms were associated with reddish-brown rots expanding from the root to the collar with sparse off-color foliage. Based on the percentage of the total infected samples across 18 vineyards, the most common oomycete species were Globisporangium intermedium (37.1%), Phytopythium vexans (34.3%), G. sylvaticum (14.3%), G. heterothallicum (11.4%), and Pythium dissotocum (2.9%). The morphological identification of isolates was confirmed based on partial DNA sequences containing the nuclear rDNA internal transcribed spacer region (rDNA ITS) and the mitochondrial cytochrome c oxidase subunit II (coxII) gene. The optimum growth temperature and the optimum pH of 5 species ranged from 22.98 to 28.25°C and 5.67 to 8.51, respectively. Pathogenicity tests on the seedlings of kiwifruit cv. Hayward revealed significant differences in virulence among isolates. Phytopythium vexans and G. sylvaticum isolates caused severe root and collar rot resulting in seedling death, while G. heterothallicum and G. intermedium isolates had relatively lower virulence. All Globisporangium spp. and P. vexans isolates significantly decreased plant growth parameters (plant height, shoot and root dry weights and root length); however, P. dissotocum caused very mild symptoms and did not affect these parameters of growth. To our knowledge, this is the first study reporting G. sylvaticum, G. heterothallicum, and G. intermedium causing root and collar rot on kiwifruit not only in Turkey but also in the world.

DOMESTICATION AND FORMULATION OF RHIZOPODOPSIS JAVENSIS AS A TEMPEH STARTER

ABSTRACT Domestication of wild fungal strains involved in the manufacture of traditional fermented foods often occurs spontaneously. Rhizopodopsis javensis (Rh. javensis) is taxonomically close to Rhizopus. The wild strain Rhizopodopsis javensis has found in cool climates can be developed as a starter in tempeh production in temperate regions. Before formulating it as a tempeh starter, a wild strain of Rh. javensis needs to be domesticated in human-made niches. A wild strain of Rh. javensis was domesticated by subculture using rice flour media at optimum growth temperature and carried out every five days. The spore's density and viability and the starter's water content were used to determine its quality. The results showed that Rh. javensis grew optimally at 22 ℃. With seven-time subcultures using rice flour media, the domestication process did not change the Rh. javensis growth rate and colony appearance. The growth rate of Rh. javensis is relatively the same as that of commercial tempeh starter and pure R. microsporus var. oligosporus, at each optimal growth temperature. In the rice flour media as a carrier, Rh. javensis produces spore's density that is relatively the same as that of commercial tempeh starter but with lower spore's viability and higher water content. Therefore, Rh. javensis cannot be used as a starter to produce tempeh in the temperate region. The carrier material and drying processes still need to be modified to increase spore viability and improve the overall quality, including the starter's lifespan. Keywords: food fermentation, Rhizopus microsporus var. oligosporus, spore's viability, starter quality, wild strain ABSTRAK Domestikasi galur liar kapang yang terlibat dalam dalam pembuatan makanan fermentasi tradisional, sering terjadi secara spontan. Rhizopodopsis javensis (Rh. javensis) merupakan salah satu galur liar kapang yang memiliki hubungan taksonomi dekat dengan Rhizopus. Strain liar ini ditemukan di daerah beriklim sejuk, sehingga berpotensi untuk dikembangkan sebagai starter tempe untuk produksi di daerah beriklim sedang. Untuk mendapatkan kultur yang tumbuh subur di relung (niches) buatan manusia, strain liar Rh. javensis perlu didomestikasi terlebih dahulu. Penelitian ini bertujuan untuk mendomestikasi strain Rh. javensis liar yang dilanjutkan dengan memformulasikannya sebagai starter tempe. Domestikasi dilakukan dengan menumbuhkan strain liar Rh. javensis pada media tepung beras pada suhu pertumbuhan optimum dan diulangi setiap lima hari. Kerapatan dan viabilitas spora, serta kadar air starter digunakan sebagai penilaian keberhasilan starter. Hasil penelitian menemukan Rh. javensis tumbuh optimal pada suhu 22 ℃. Domestikasi dengan cara subkultur koloni Rh. javensis pada media tepung beras selama 7 kali tidak mengubah kecepatan pertumbuhan Rh. javensis dan penampakan koloni. Laju pertumbuhan Rh. javensis relatif sama dengan laju pertumbuhan starter tempe komersial dan R. microsporus var. oligosporus murni, pada suhu optimum pertumbuhan masing-masing. Formulasi tepung beras sebagai media pembawa starter Rh. javensis, menghasilkan kerapatan spora yang relatif sama dengan starter tempe komersial, namun viabilitas sporanya rendah dan kadar airnya tinggi. Starter Rh. javensis belum dapat digunakan untuk membuat tempe. Substrat dan proses pengeringan masih perlu dimodifikasi untuk meningkatkan viabilitas spora dan kualitas starter tempe secara keseluruhan, termasuk umur simpan starter. Keywords: fermentasi makanan, kualitas starter, Rhizopus microsporus var. oligosporus, strain liar, viabilitas spora

Evaluation of the Properties of the DNA Methyltransferase from Aeropyrum pernix K1

In general, thermophilic bacteria with optimum growth temperatures over or equal to 60°C have been predicted to include only N 4 -methylcytosine or N 6 -methyladenine as methylated bases in their DNA, because 5-methylcytosine is susceptible to deamination by heat. However, from this study, A. pernix K1, with an optimum growth temperature at 95°C, was demonstrated to produce a DNA (cytosine-5)-methyltransferase.

Methyloradius Palustris Gen. Nov., Sp. Nov., a Methanol-oxidizing Bacterium Isolated From Snow

A novel methylotrophic bacterium, strain Zm11 T , was isolated from reddish brown snow collected in a moor in Japan. Cells of the isolate were Gram-stain-negative, motile and rod-shaped (0.6-0.7×1.2-2.7 μm). Growth was observed at 5–32°C with an optimum growth temperature of 25–28°C. The pH range for growth was 5.4–7.8 with an optimum pH of 6.8. The strain utilized only methanol as carbon and energy sources for aerobic growth. The major cellular fatty acids (>40% of total) were summed feature 3 (C 16:1 ω 7 c and/or C 16:1 ω 6 c ) and C 16 : 0 . The predominant quinone was Q-8. The complete genome of strain Zm11 T is composed of a circular chromosome (2,800,413 bp), with G + C content of 46.4 mol%. Phylogenetic analyses were conducted based on the 16S rRNA gene sequence and conserved proteins encoded in the genome. The results of analyses indicate that strain Zm11 T is a member of the family Methylophilaceae but does not belong to any existing genus. On the basis of its genomic and phenotypic properties, strain Zm11 T (= DSM111909 T = NBRC114766 T ) is proposed as the type strain of a new species in a new genus, Methyloradius palustris gen. nov., sp. nov.

The Effects of Temperature on the Growth of a Lead-Free Perovskite-Like (CH3NH3)3Sb2Br9 Single Crystal for An MSM Photodetector Application

We have fabricated a photodetector based on (CH3NH3)3Sb2Br9 (MA3Sb2Br9) lead-free perovskite-like single crystal, which plays an important role in the optoelectronic characteristics of the photodetector as a perovskite-like photosensitive layer. Here, MA3Sb2Br9 single crystals were synthesized by an inverse temperature crystallization process with a precursor solution at three different growth temperatures, 60 °C, 80 °C, and 100 °C. As a result, a MA3Sb2Br9 single crystal with an optimum growth temperature of 60 °C presented a low trap density of 2.63 × 1011 cm−3, a high charge carrier mobility of 0.75 cm2 V−1 s−1, and excellent crystal structure and optical absorption properties. This MA3Sb2Br9 perovskite-like photodetector displayed a low dark current of 8.09 × 10−9 A, high responsivity of 0.113 A W−1, and high detectivity of 4.32 × 1011 Jones.

Growth Optimisation and Kinetic Profiling of Diesel Biodegradation by a Cold-Adapted Microbial Consortium Isolated from Trinity Peninsula, Antarctica

Pollution associated with petrogenic hydrocarbons is increasing in Antarctica due to a combination of increasing human activity and the continent’s unforgiving environmental conditions. The current study focuses on the ability of a cold-adapted crude microbial consortium (BS24), isolated from soil on the north-west Antarctic Peninsula, to metabolise diesel fuel as the sole carbon source in a shake-flask setting. Factors expected to influence the efficiency of diesel biodegradation, namely temperature, initial diesel concentration, nitrogen source type and concentration, salinity and pH were studied. Consortium BS24 displayed optimal cell growth and diesel degradation activity at 1.0% NaCl, pH 7.5, 0.5 g/L NH4Cl and 2.0% v/v initial diesel concentration during one-factor-at-a-time (OFAT) analyses. The consortium was psychrotolerant based on the optimum growth temperature of 10‒15 °C. In conventionally optimised media, the highest total petroleum hydrocarbons (TPH) mineralisation was 85% over a 7-day incubation. Further optimisation of conditions predicted through statistical response-surface methodology (RSM) (1.0% NaCl, pH 7.25, 0.75 g/L NH4Cl, 12.5 °C and 1.75% v/v initial diesel concentration) boosted mineralisation to 95% over a 7-day incubation. A Tessier secondary model best described the growth pattern of BS24 in diesel-enriched medium, with maximum specific growth rate, μmax, substrate inhibition constant, Ki and half saturation constant, Ks, being 0.9996 h−1, 1.356% v/v and 1.238% v/v, respectively. The data obtained suggest the potential of microbial consortia such as BS24 in bioremediation applications in low-temperature diesel-polluted soils.

First report of leaf spots caused by Pestalotiopsis trachicarpicola in Gentiana rhodantha

In August 2018, leaf spots were widely found with circular or irregular brown lesions on Gentiana rhodantha leaves in Liupanshui, Guizhou Province, China. Three strains of Pestalotiopsis spp were associated with leaf lesions by single-spore isolation. Based on asexual and sexual characteristics and multi-locus (ITS, TUB, tef-1 ) phylogenies data, strains were identified as Pestalotiopsis trachicarpicola . This is the first report of G. rhodantha leaf spot caused by P. trachicarpicola . The fungal culture tests showed that mycelia optimum growth temperature and pH were 20–25°C and pH 7–9, and for conidia germination were 25–30°C and pH 6–9, respectively.

Characterization of multiple metal resistant Bacillus licheniformis and its potential use in arsenic contaminated industrial wastewater

In the present study, the arsenic bioremediation ability of Bacillus licheniformis (dubbed as A6) was determined. The strain was isolated from metal polluted wastewater and was identified on the basis of 16S rRNA sequence homology with accession number of KX 785,171. The bacterium showed resistance against multiple toxic heavy metals, and MIC against arsenic was 3000 µg/ml. Resistance of the bacterium against other toxic metal ions was 3000 µg/ml (Cr), 50 µg/ml (Hg), 1000 µg/ml (Mn), 4000 µg/ml (Se), 500 µg/ml (Pb), 100 µg/ml (Co), 70 µg/ml (Cd) and 100 µg/ml (Zn). The optimum growth temperature was 37 °C while pH was 7. The strain also showed resistance against commonly used antibiotics except ceftriaxone 30 µg and amoxicillin with clavulanic acid (2:1) 3 µg. B. licheniformis could oxidize arsenite into arsenate 86 and 98% after 48 and 96 h from the medium at optimum growth conditions. Due to its high oxidation potential, B. licheniformis can be used in the biological treatment of wastewater containing arsenic.