Caixin Yang , Xingxing Lian , Yanpeng Cheng , Yifan Jiao , Jing Yang , Kui Dong , Shan Lu , Xin-He Lai , Dong Jin , Han Zheng , Ji Pu , Suping Wang , Liyun Liu , Jianguo Xu
J. Microbiol. 2022;60(6):585-593. Published online April 18, 2022
Two Gram-stain-positive, catalase-negative, non-spore-forming,
cocci-shaped strains (dk850T and JY899) were isolated
from the feces of Equus kiang in the Qinghai-Tibet Plateau of
China. 16S rRNA gene sequence-based phylogenetic analyses
showed that strains dk850T and JY899 belong to the genus
Flaviflexus, closest to F. salsibiostraticola KCTC 33148T, F. ciconiae
KCTC 49253T and F. huanghaiensis H5T. The DNA
G + C content of strain dk850T was 62.9%. The digital DNADNA
hybridization values of strain dk850T with the closely related
species were below the 70% threshold for species demarcation.
The two strains grew best at 28°C on brain heart infusion
(BHI) agar with 5% sheep blood. All strains had C18:1ω9c
and C16:0 as the major cellular fatty acids. MK-9(H4) was the
major menaquinone in strain dk850T. The major polar lipids
included diphosphatidylglycerol and an unidentified phospholipid.
Strains dk850T and JY899 were identified as carrying
a class 1 integron containing the aminoglycoside resistance
gene aadA11, both strains were resistant to spectinomycin
and streptomycin. Based on several lines of evidence
from phenotypic and phylogenetic analyses, strains dk850T
and JY899 represent a novel species of the genus Flaviflexus,
for which the name Flaviflexus equikiangi sp. nov. is proposed.
The type strain is dk850T (= CGMCC 1.16593T = JCM 33598T).
A Gram-stain-negative, non-spore-forming, facultative, rodshaped
bacterium (designated LA-28T) was isolated from a
sludge sample from a wastewater treatment plant in Hanam
city, Republic of Korea. On the basis of 16S rRNA gene sequencing,
strain LA-28T clustered with species of the genus
Mesorhizobium and appeared closely related to M. jarvisii
LMG 28313T (96.8%), M. waimense ICMP 19557T (96.7%),
and M. huakuii LMG 14107T (96.7%). Growth occurs at 18–
40°C on R2A medium in the presence of 1–4% NaCl (w/v)
and at pH 6–8. The DNA G+C content was 61.2 mol%, and
the predominant quinone was ubiquinone-10 (Q-10). The
major cellular fatty acids (> 5%) were C16:0, C19:0 ω8c cyclo,
C18:1 ω7c 11-methyl, and C18:1 ω7c and/or C18:1 ω6c (summed
feature 8). Major polar lipids were phosphatidylglycerol (PG),
phosphatidylethanolamine (PE), phosphatidyl-N-methylethanolamine
(PME), and phosphatidylcholine (PC). Physiological
and biochemical characteristics indicated that strain
LA-28T represents a novel species of the genus Mesorhizobium,
for which the name Mesorhizobium denitrificans sp.
nov. is proposed. The type strain is LA-28T (= KACC 19675T
= LMG 30806T).