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14 results on '"Hao, Do Manh"'

3. Distribution and density of Lutraria rhynchaena Jonas, 1844 relate to sediment while reproduction shows multiple peaks per year in Cat Ba-Ha Long Bay, Vietnam

Author

Hao Do Manh, Sy Do Trung, Tuyet Dao Thi Anh, Hiep Le Minh, Dat Nguyen Tien, Huong Do Thi Thu, Thung Do Cong, Nhon Dang Hoai, Lan Tran Dinh, and Van Quan Nguyen

Subjects
lutraria rhynchaena, cat ba-ha long bay, distribution, density, reproductive cycle, Biology (General), QH301-705.5
Abstract

Lutraria rhynchaena Jonas, 1844 is of great commercial interest, but its reserves have dramatically declined over recent decades. Therefore, there is an urgent need of scientific basis to propose effective fishery management measures and improve artificial aquaculture of the clam. In this study, we investigated the distribution and density of L. rhynchaena, sediment characteristics, and established the clam’s reproductive cycle through monthly observations from August 2017 to July 2018. The study results showed that distribution and density of clams are related to sediment types, and the sediment type of medium sand is likely the best benthic substrate for the clams. The spawning of clams occurred throughout the year with three spawning peaks in January, April and September. For the sustainable management of the clam resource in Cat Ba-Ha Long Bay, the fishery authorities can issue a ban on harvest of the clam in spawning peak months in January, April and September.

Published
2020
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4. Density and de-nitrifying potential of indigenous bacterial assemblage in mangrove and seagrass in the North of Vietnam

Author

Huyen Le Thanh, Anh Tuyet Dao Thi, Hiep Le Minh, Dat Nguyen Tien, Binh Ha Thi, Sy Do Trung, and Hao Do Manh

Abstract

This study assessed the density and de-nitrification potential of indigenous microorganisms in mangroves and seagrass beds in northern Vietnam through two mangrove ecosystems in Tien Yen - Quang Ninh and Bang La - Hai Phong and three seagrass beds in Ha Coi and Dam Ha - Quang Ninh and Tam Giang - Thua Thien Hue. The analysis results of 4 sampling times in rainy and dry seasons during 2017–2019 showed that the density of de-nitrifying bacteria ranged from (1.0 × 102)–(4.6 × 103) MPN/mL, averaging 1.1 ± 0.3 × 103 MPN/mL. The density in mangroves was higher than that in seagrass (a = 0.05). De-nitrification rates ranged from 0.0 µgN/wet to 69.0 µgN/wet soil g/hour, averaging 18.4 ± 7.4 µgN/wet soil g/hour. The rate at the experiments added 0.5 mgN/L in seagrass was higher than that in the mangrove. The density and rate of de-nitrification were significantly correlated with many environmental factors, especially density of sulfur-oxidizing bacteria, the density of nitrifying bacteria, pH, Eh, Nts, N-NH4, P- PO4 and BOD5.

Published
2021
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9. Robiginitalea myxolifaciens sp. nov., a novel myxol-producing bacterium isolated from marine sediment, and emended description of the genus Robiginitalea

Author

Yoshihide Matsuo, Hiroaki Kasai, Satoru Matsuda, Atsuko Katsuta, Yoshikazu Shizuri, and Hao Do Manh

Subjects
Geologic Sediments, Phylogenetic tree, Fatty Acids, Molecular Sequence Data, General Medicine, Biology, Ribosomal RNA, 16S ribosomal RNA, biology.organism_classification, Microbiology, Carotenoids, Japan, Species Specificity, Phylogenetics, RNA, Ribosomal, 16S, Genotype, Taxonomy (biology), Gene, Flavobacteriaceae, Ecology, Evolution, Behavior and Systematics, Bacteria, Phylogeny
Abstract

A marine, Gram-negative, deep-orange-coloured, rod/coccoid-shaped, strictly aerobic, non-motile, oxidase- and catalase-positive bacterial strain, designated YM6-073(T), was isolated from sediment collected in Okinawa, Japan. Strain YM6-073(T) produced the carotenoid (3R,2'S)-myxol. A phylogenetic analysis based on 16S rRNA gene sequences revealed that strain YM6-073(T) belonged to a distinct lineage in the family Flavobacteriaceae, the closest relative being Robiginitalea biformata HTCC2501(T) (93.7 % sequence similarity). Strain YM6-073(T) could be distinguished from other members of the family Flavobacteriaceae by means of a number of phenotypic characteristics. The DNA G+C content was 50.1 mol%. The predominant cellular fatty acids were iso-C(15 : 0), iso-C(15 : 1)omega10c, iso-C(17 : 0) 3-OH and C(15 : 0,) and menaquinone-6 was the only respiratory quinone. DNA-DNA hybridization between strain YM6-073(T) and R. biformata DSM 15991(T) showed less than 10 % DNA-DNA relatedness. On the basis of phenotypic, genotypic and phylogenetic features, strain YM6-073(T) represents a novel species of the genus Robiginitalea, for which the name Robiginitalea myxolifaciens sp. nov. is proposed. The type strain is YM6-073(T) (=MBIC 06409(T)=KCTC 22216(T)=DSM 21019(T)).

Published
2008

12. Population Dynamics of Crenarchaeota and Euryarchaeota in the Mixing Front of River and Marine Waters

Author

Hao Do Manh, Tashiro Tomokazu, Kato Miharu, Sohrin Rumi, Ishibashi Tomotaka, Katsuyama Chie, Nagaosa Kazuyo, Kimura Hiroyuki, Thanh Tran Duc, Kato Kenji, Hao Do Manh, Tashiro Tomokazu, Kato Miharu, Sohrin Rumi, Ishibashi Tomotaka, Katsuyama Chie, Nagaosa Kazuyo, Kimura Hiroyuki, Thanh Tran Duc, and Kato Kenji

Abstract

A transect from the Tomoe River Mouth through Shimizu Port to Suruga Bay, Japan, was examined between 2005 and 2009 to reveal the population dynamics of Crenarchaeota and Euryarchaeota in an estuary environment. Crenarchaeota tended to increase in abundance in waters deeper than 100 m compared with Euryarchaeota, and comprised 11% of total direct counts. Archaeal abundance was highest in the Tomoe River Mouth, with a strong negative correlation between surface euryarchaeal abundance and salinity (P<0.001). The diversity index for the phylotypic archaeal community in the mouth was three times higher than that at sites St1-1m and St1-10m in the estuary, and OTUs represented most of the OTU groups at the sites. Three of the seven total OTUs, which comprised 83.6% of the 140 sequenced clones in the estuary, were related to the OTUs in the mouth with similarities higher than 97%. A significant proportion of the archaeal community appears to be derived from the Tomoe River. The two dominant phylotypes of the archaeal community in Shimizu Port, belonging to MGI and MGII, occurred ubiquitously., publisher

Published
2010

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