Neuroimage Biomarker Identification of the Conversion of Mild Cognitive Impairment to Alzheimer's Disease.

An efficient method to identify whether mild cognitive impairment (MCI) has progressed to Alzheimer's disease (AD) will be beneficial to patient care. Previous studies have shown that magnetic resonance imaging (MRI) has enabled the assessment of AD progression based on imaging findings. The present work aimed to establish an algorithm based on three features, namely, volume, surface area, and surface curvature within the hippocampal subfields, to model variations, including atrophy and structural changes to the cortical surface. In this study, a new biomarker, the ratio of principal curvatures (RPC), was proposed to characterize the folding patterns of the cortical gyrus and sulcus. Along with volumes and surface areas, these morphological features associated with the hippocampal subfields were assessed in terms of their sensitivity to the changes in cognitive capacity by two different feature selection methods. Either the extracted features were statistically significantly different, or the features were selected through a random forest model. The identified subfields and their structural indices that are sensitive to the changes characteristic of the progression from MCI to AD were further assessed with a multilayer perceptron classifier to help facilitate the diagnosis. The accuracy of the classification based on the proposed method to distinguish whether a MCI patient enters the AD stage amounted to 79.95%, solely using the information from the features selected by a logical feature selection method.

Flavobacterium undicola sp. nov., isolated from a freshwater lake.

Bacterial strain BBQ-18T, isolated from a freshwater lake in Taiwan, is characterized using a polyphasic taxonomy approach. Phylogenetic analyses based on 16S rRNA gene sequences and coding sequences of 92 protein clusters indicate that strain BBQ-18T forms a phylogenetic lineage in the genus Flavobacterium. Strain BBQ-18T is most closely related to Flavobacterium alvei HR-AYT with 98.5% 16S rRNA gene sequence similarity. Strain BBQ-18T shows 70.5-89.5% average nucleotide identity and 13.7-38.2% digital DNA-DNA hybridization identity with the type strains of other closely related Flavobacterium species. The strain is Gram-stain negative, strictly aerobic, motile by gliding, rod shaped and formed yellow colonies. Optimal growth occurs at 25 °C, pH 6, and in the absence of NaCl. Strain BBQ-18T contains iso-C15:0, summed feature 3 (C16:1ω6c and/or C16:1ω7c) and anteiso-C15:0 as the predominant fatty acids. The polar lipid profile consists of phosphatidylethanolamine, four uncharacterized aminophospholipids and two uncharacterized phospholipids. The major polyamine is homospermidine. The major isoprenoid quinone is MK-6. The DNA G+C content of the genomic DNA is 33.8%. Differential phenotypic properties, together with the phylogenetic inference, demonstrate that strain BBQ-18T should be classified as a novel species of the genus Flavobacterium, for which the name Flavobacterium undicola sp. nov. is proposed. The type strain is BBQ-18T (= BCRC 81050T = LMG 30052T = KCTC 52810T).

Rhodovarius crocodyli sp. nov., isolated from a crocodile pond.

Bacterial strain CCP-6T, isolated from a freshwater pond in Taiwan, was characterized using a polyphasic taxonomy approach. Phylogenetic analyses based on 16S rRNA gene sequences and an up-to-date bacterial core gene set (92 protein clusters) indicated that strain CCP-6T is affiliated with species in the genus Rhodovarius. Strain CCP-6T was most closely related to Rhodovarius lipocyclicus CCUG 44693T with a 98.9% 16S rRNA gene sequence similarity. Cells were Gram-stain-negative, aerobic, non-motile, rod-shaped and formed light pink-coloured colonies. Optimal growth occurred at 30 °C, pH 6 and in the absence of NaCl. The major fatty acids of strain CCP-6T were C18 : 1 ω7c, C16 : 0 and C19 : 0 cyclo ω8c. The polar lipid profile consisted of phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine, phosphatidyldimethylethanolamine, phosphatidylmethylethanolamine, diphosphatidylglycerol, three unidentified aminophospholipids and an unidentified phospholipid. The predominant polyamine was spermidine. The major isoprenoid quinone was Q-10. The DNA G+C content of the genomic DNA was 69.3 mol%. Strain CCP-6T showed 85.8% average nucleotide identity and 14.5% digital DNA-DNA hybridization identity with Rhodovarius lipocyclicus CCUG 44693T. On the basis of the genotypic, chemotaxonomic and phenotypic data, strain CCP-6T represents a novel species in the genus Rhodovarius, for which the name Rhodovarius crocodyli sp. nov. is proposed. The type strain is CCP-6T (=BCRC 81095T=LMG 30310T=KCTC 62188T).

Mucilaginibacter limnophilus sp. nov., isolated from a lake.

A polyphasic taxonomy approach was used to characterize strain YBJ-36T, isolated from a freshwater lake in Taiwan. Phylogenetic analyses, based on 16S rRNA gene sequences and coding sequences of an up-to-date bacterial core gene set (92 protein clusters), indicated that strain YBJ-36T formed a phylogenetic lineage in the genus Mucilaginibacter. 16S rRNA gene sequence similarity indicated that strain YBJ-36T is closely related to species within the genus Mucilaginibacter (93.8-97.8% sequence similarity) and is most similar to Mucilaginibacter fluminis TTM-2T (97.8%), followed by Mucilaginibacter roseus TTM-1T (97.2%). Microbiological analyses demonstrated that strain YBJ-36T is Gram-negative, aerobic, non-motile, rod-shaped, surrounded by a thick capsule, and forms pink-colored colonies. Strain YBJ-36T grew between 20-40°C (optimal range, 35-37°C), pH 5.5-7.0 (optimal pH of 6) and 0-2% NaCl (optimal concentration, 0.5%). The predominant fatty acids of strain YBJ-36T are iso-C15:0 and summed feature 3 (C16:1ω7c and/or C16:1ω6c), the major polar lipid is phosphatidylethanolamine, the major polyamine is homospermidine, and the major isoprenoid quinone is MK-7. The draft genome is approximately 4.63 Mb in size with a G+C content of 42.8 mol%. Strain YBJ-36T exhibited less than 35% DNA-DNA relatedness with Mucilaginibacter fluminis TTM-2T and Mucilaginibacter roseus TTM-1T. Based on phenotypic and genotypic properties and phylogenetic inference, strain YBJ-36T should be classified in a novel species of the genus Mucilaginibacter, for which the name Mucilaginibacter limnophilus sp. nov. is proposed. The type strain is YBJ-36T (= BCRC 81056T = KCTC 52811T = LMG 30058T).

Inhella crocodyli sp. nov., isolated from a crocodile pond.

Strain CCP-18T, isolated from a freshwater pond in Taiwan, was characterized by using a polyphasic taxonomy approach. Phylogenetic analyses based on 16S rRNA gene sequences indicated that strain CCP-18T belongs to the genus Inhella and has the highest levels of sequence similarity with respect to Inhella inkyongensis IMCC1713T (98.9 %) and Inhella fonticola TNR-25T (98.0 %). Cells were Gram-stain-negative, aerobic, motile, rod-shaped and formed white-coloured colonies. Optimal growth occurred at 25 °C, pH 6 and in the absence of NaCl. The major fatty acids of strain CCP-18T were summed feature 3 (comprising C16 : 1ω7c and/or C16 : 1ω6c) and C16 : 0. The polar lipid profile consisted of phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, two unidentified aminophospholipids, an unidentified phospholipid, an unidentified aminolipid and an unidentified lipid. The predominant polyamine was putrescine. The major isoprenoid quinone was Q-8. The draft genome was approximately 3.76 Mb in size with a G+C content of 68.9 mol%. The DNA-DNA hybridization values for strain CCP-18Twith I.inkyongensis IMCC1713T and I.nhella fonticola TNR-25T were less than 40 %. Based on the phylogenetic and phenotypic data, strain CCP-18T should be classified within the genus Inhella as a representative of a novel species, named Inhella crocodyli sp. nov. The type strain is CCP-18T (=BCRC 81120T=LMG 30595T=KCTC 62511T).

Sphingomonas crocodyli sp. nov., isolated from a crocodile pond.

Strain CCP-7T, isolated from a freshwater pond in Taiwan, was characterized using a polyphasic taxonomy approach. Phylogenetic analyses based on 16S rRNA gene sequences and coding sequences of 92 protein clusters indicated that strain CCP-7T formed a phylogenetic lineage in the genus Sphingomonas. Strain CCP-7T was most closely related to Sphingomonas starnbergensis 382T and Sphingomonas naphthae DKC-5-1T with 96.2 % 16S rRNA gene sequence similarity. Strain CCP-7T showed 65.5-76.7 % average nucleotide identity and 20.2-22.5 % digital DNA-DNA hybridization identity with the strains of other related Sphingomonas species. Cells were Gram-stain-negative, aerobic, motile, rod-shaped and formed light orange-coloured colonies. Optimal growth occurred at 30 °C, pH 6 and in the absence of NaCl. The major fatty acid of strain CCP-7T was C18 : 1ω7c. The polar lipid profile consisted of phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, phosphatidylmonomethylethanolamine, three uncharacterized sphingoglycolipids, two uncharacterized phospholipids and six uncharacterized lipids. The predominant polyamine was homospermidine. The only isoprenoid quinone was Q-10. Genomic DNA G+C content of strain CCP-7T was 64.5 %. On the basis of phenotypic and genotypic properties and phylogenetic inference, strain CCP-7T should be classified in a novel species of the genus Sphingomonas, for which the name Sphingomonas crocodyli sp. nov. is proposed. The type strain is CCP-7T (=BCRC 81096T=LMG 30311T=KCTC 62190T).

Flavobacterium sufflavum sp. nov., isolated from a freshwater lake.

A bacterial strain, BBQ-12T, was isolated from a freshwater lake in Taiwan. The strain was Gram-stain-negative, strictly aerobic, motile by gliding, rod-shaped and formed yellow colonies. Optimal growth occurred at 25 °C, pH 6 and in the absence of NaCl. Phylogenetic analyses based on 16S rRNA gene sequences and coding sequences of 92 protein clusters indicated that strain BBQ-12T formed a phylogenetic lineage in the genus Flavobacterium. Strain BBQ-12T was most closely related to Flavobacterium fluminis 3R17T with 98.1 % 16S rRNA gene sequence similarity. Strain BBQ-12T showed 74.4-83.1 % average nucleotide identity and 16.0-21.8 % digital DNA-DNA hybridization identity with the type strains of other closely related Flavobacterium species. Strain BBQ-12T contained iso-C15 : 0, summed feature 3 (C16 : 1ω6c and/or C16 : 1ω7c) and anteiso-C15 : 0 as the predominant fatty acids. The polar lipid profile consisted of phosphatidylethanolamine, four uncharacterized aminophospholipids and three uncharacterized phospholipids. The major polyamine was homospermidine. The major isoprenoid quinone was MK-6. The DNA G+C content of the genomic DNA was 34.2 mol%. Differential phenotypic properties, together with the phylogenetic inference, demonstrate that strain BBQ-12T should be classified as a novel species of the genus Flavobacterium, for which the name Flavobacteriumsufflavum sp. nov. is proposed. The type strain is BBQ-12T (=BCRC 81049T=LMG 30051T=KCTC 52809T).