Nguyen Vu Thanh

Polyoxygenated steroids from the gorgonian Menella woodin with capabilities to modulate ROS levels in macrophages at response to LPS.

Four new polyoxygenated sterol derivatives (1-4) along with the compounds (5-7) previously known from other biological sources were isolated from the gorgonian Menella woodin, collected from the Vietnamese waters. Structures of 1-4 were elucidated by the detailed NMR spectroscopic and mass-spectrometric analyses as well as comparison with those reported in literature data. Compounds 1, 4, and 6 decrease the production of reactive oxygen species (ROS) by the murine macrophages of RAW 264.7 line at induction by endotoxic lipopolysaccharide (LPS) from Escherichia coli.

Meiobenthos in estuary part of ha long bay (gulf of tonkin, south china sea, vietnam)

The distribution of the taxonomical composition and the density of meiobenthos depending on some factors of environment has been studied in bottom sediments of the northern estuary part of Ha Long Bay (Cua Luc estuary). The basic factor of influence on meiobenthic community structure was the granulometric composition of sediment. The greatest taxonomic diversity is noted in the silted sands, lowest — in the silty sediments. The density of meiobenthic community was higher in the silty sediments. Slightly expressed correlation between the density of nematodes and the percentage of silty particles in the sediments is detected (Spearman rank correlation coefficient was 0.49±0.21, p=0.035). The nematodes were dominant at all stations. In total, representatives of 66 species of nematodes belonging to 17 families and 52 genera were identified.

Paracomesoma paralongispiculum sp. n.: a New species of nematode from mangroves of Can Gio (Vietnam) and taxonomy of the genus Paracomesoma Hope et Murphy, 1972 (Nematoda: Araeolaimida)

A literature review reveals that 13 species are described belonging to the genus Paracomesoma Hope and Murphy, 1972. In Can Gio mangrove forest, Ho Chi Minh city, Vietnam, one new species Paracomesoma paralongispiculum n. sp. was found, which brings the number of species up to 14. This species differs from all known species of this genus by its very long spicules (12 times a.b.d) and 11–12 papillae supplements all confined within the spicular region.

Three new species of nematodes (Nematoda: Enoplida) from coastal waters of Vietnam

Three new species of free-living nematodes of the order Enoplida from coastal shallow waters of northern Vietnam are described and illustrated. Paramesacanthion vietnamicum sp. n. is morphologically close to P. oxycephalum (Ditlevsen, 1926), P. truncum Vitiello, 1971, and P. hirsutum Warwick, 1970; however, it differs in lacking subcephalic setae and in having articulate cephalic setae in the males. Viscosia pygmaea sp. n. is morphologically similar to V. parva Kreis, 1929 but differs in having a shorter body and a shorter and thicker tail in the females. V. pygmaea is distinguished from V. megalaima (Ditlevsen, 1928) by its shorter body, longer cephalic setae, more slender tail, and the position of the vulva. Viscosia longicaudatoides sp. n. can be distinguished from V. parva and V. timmi Gagarin, Nguyen Vu Thanh, 2007 by its thinner body, longer and more slender tail, and shorter and narrower stoma. In contrast to V. timmi, it has short spicules and lacks vesicle-like cells between the gut and the longitudinal chords.

A new genus and two new species of marine free-living nematodes from the coastal waters of Southern Vietnam

A new genus and two new species of free-living marine nematodes from sediments in the coastal zone of the South China Sea (Vietnam) are described. Cyartonemoides gen. n. morphologically resembles Cyartonema Cobb, 1920, but differs from it in having a well-developed cephalic capsule. Cyartonemoides foetidus gen. n., sp. n. is the type and the only species of the genus. Campylaimus abnormis sp. n. differs from all species of the genus Campylaimus Cobb, 1920 by the shape of the amphidial fovea and shorter lateral fields.

Two New Nematode Species (Nematoda) from the Mangroves of the Yen River Delta, Vietnam

An illustrated description of two free-living nematode species, Belbolla gracilis sp. n. and Pseudolella mangrovi sp. n., which were discovered in the sediments of the mangroves in the Yen River Estuary in Vietnam, is provided. Beldolla gracilis sp. n. is similar to B. heptabulba Timm, 1961 and B. warwick Huang, Zhang, 2005 in its oesophagus morphology but it differs from these species in its longer and more slender tail, longer stoma, and longer spicules. Pseudolella mangrovi sp. n. is similar to P. capera Tchesunov, 1978 and P. parva Gagarin, Nguyen Vu Thanh, 2006 in the morphology and the shape of the amphidal fovea, but it is characterized by a shorter body and longer spicules.

Two new nematode species of the genus Daptonema Cobb, 1920 (Nematoda, Xyalidae) from mangrove forest estuary of the Red River (Vietnam)

Illustrated discriptions are given of two new marine free-living nematode species of the genus Daptonema Cobb, 1920, D. paraoxyuroides sp. n. and D. balatum sp. n., found in the estuary of the Red River in North Vietnam. D. paraoxyuroides sp. n. resembles D. oxyuroides, but differs from it in its shorter and thicker body, less slender tail, shorter cephalic setae, and shorter spicules. D. balatum sp. n. differs from all known valid species of the genus Daptonema by the special structure of the copulative apparatus of males.

Bolbolaimus obesus sp. n. (Nematoda, Desmodorida) from Mangrove Thickets in the Tien Yen River Estuary, Vietnam

An illustrated description of the nematode Bolbolaimus obesus sp. n. from a mangrove forest of the Yen River estuary, Vietnam is given. Bolbolaimus obesus sp. n. is close to B. abebei Muthumbi et Vincx 1999 and B. bahari Muthumbi et Vincx 1999, but differs from both by the shorter body, strongly sclerotized body walls of the cheilostoma, a different position of the amphidial fovea, and longer gubernaculum.

Two new species of the genus Deontolaimus de Man, 1880 (Nematoda: Leptolaimidae) from mangrove ecosystems of Vietnam

Two new species of the free-living marine nematode genus Deontolaimus (Leptolaimidae) are described from mangrove forests of the Can Gio Biosphere Reserve and Tien Yen, Quang Ninh, Vietnam. D. mangrovi sp. nov. is distinguished from D. papillatus de Man, 1880 and D. cangioensis sp. nov. by tail shape: conical and then elongated, without pointed tip. Deontolaimus cangioensis sp. nov. resembles D. papillatus in body shape, especially in the pointed tail terminus. D. cangioensis differs from D. papillatus in having a complicated gubernaculum with dorsally curved apophyses.

Four new species of monhysterids (Nematoda: Monhysterida) from mangroves of the Mekong river estuaries of Vietnam

Four new free-living nematode species of the order Monhysterida from Me Kong River estuaries of Vietnam are described. Thalassomonhystera tenuis sp. nov. resembles to Thalassomonhystera pusilla (Boucher, Heleouet, 1977) but differs from it by the high, isolated labial region, longer outer labial setae, shorter oesophagus, shorter spicules, absence of gubernaculum’s dorso-caudal apophysis and presence of subterminal setae on the tip. Diplolaimelloides elegans sp. nov. resembles to Diplolaimelloides meyli Timm, 1961, but it differs in having longer and slender tail and vulva position located in more anterior body end. Sphaerotheristus supplementatus sp. nov. comes close to Sphaerotheristus parvus Gagarin, Nguyen Vu Thanh, 2006, it differs in having the longer and thinner body and papillae-shaped supplements in males. Terschellingia obesa sp. nov. similar to Terschellingia monohystera Wieser, Hopper 1967 and Terschellingia brevicaudata Ott, 1972, but it differs from T. monhystera in having shorter cephalic setae, others vulva position and absence of oesophagus basal bulb; it also differs from T. brevicaudata in having shorter body, shorter cephalic setae, shorter spicules and presence of one ovary.