Three new species, one new genus and subfamily of Dorylaimida (de Man, 1876) Pearse, 1942, and revisions on the families Tylencholaimellidae Jairajpuri, 1964 and Mydonomidae Thorne, 1964 (Nematoda: Dorylaimida).

Three new species of the order Dorylaimida (de Man, 1876) Pearse, 1942 were identified and described. Paratylencholaimus sanshaensis gen. nov. sp. nov. from Hainan is proposed as a new member of the family Tylencholaimellidae Jairajpuri, 1964. Paratylencholaimus gen. nov. is close to Phellonema Thorne, 1964 and Goferus Jairajpuri & Ahmad, 1992 but can be differentiated mainly by having basal part of odontophore rod-like and without knobs, and basal part of pharynx expanded gradually. Tylencholaimus zhongshanensis sp. nov. from Guangdong and Dorylaimoides shapotouensis sp. nov. from the Ningxia Hui Autonomous Region are also described herein. Phylogenetic analyses based on the 18S rDNA and the D2-D3 region of the 28S rDNA support that the three new species are valid. The classifications of the families Tylencholaimellidae and Mydonomidae Thorne, 1964 are revised mainly based on the analysis of the morphology of odontostyle and odontophore. After these revisions, Paratylencholaiminae subfam. nov. including Paratylencholaimus gen. nov. and Goferus is proposed. Athernema and Agmodorus of Tylencholaimellidae are transferred into Mydonomidae, and the subfamily Athernematinae of Tylencholaimellidae is dismissed. The main characteristics of the family Mydonomidae and Tylencholaimellidae are revised. Keys to the genera of Mydomonidae and Tylencholaimellidae are included.

Antioxidant and Anti-inflammatory Capacity of Ferulic Acid Released from Wheat Bran by Solid-state Fermentation of Aspergillus niger.

OBJECTIVE: A strain of Aspergillus niger (A. niger), capable of releasing bound phenolic acids from wheat bran, was isolated. This strain was identified by gene sequence identification. The antioxidant and anti-inflammatory capacity of ferulic acid released from wheat bran by this A. niger strain (FA-WB) were evaluated. METHODS: Molecular identification techniques based on PCR analysis of specific genomic sequences were conducted; antioxidant ability was examined using oxygen radical absorbance capacity (ORAC), cellular antioxidant activity (CAA) assays, and erythrocyte hemolysis assays. RAW264.7 cells were used as a model to detect anti-inflammatory activity. RESULTS: The filamentous fungal isolate was identified to be A. niger. ORAC and CAA assay showed that FA-WB had better antioxidant activity than that of the ferulic acid standard. The erythrocyte hemolysis assay results suggested that FA-WB could attenuate AAPH-induced oxidative stress through inhibition of reactive oxy gen species (ROS) generation. FA-WB could significantly restore the AAPH-induced increase in intracellular antioxidant enzyme activities to normal levels as well as inhibit the intracellular malondialdehyde formation. TNF-a, IL-6, and NO levels indicated that FA-WB can inhibit the inflammation induced by lipopolysaccharide (LPS). CONCLUSION: Ferulic acid released from wheat bran by a new strain of A. niger had good anti-inflammatory activity and better antioxidant ability than standard ferulic acid.

Description and molecular analysis of Tylencholaimushelanensis sp. n. from China (Dorylaimida, Tylencholaimidea).

A new species, Tylencholaimushelanensis sp. n., extracted from the rhizosphere soil of unidentified grasses from Helan Mountain, Inner Mongolia, China was identified. The new species is characterized by having a body length of 0.93-1.07 mm with the lip region approximately one-quarter of the body diameter at the posterior end of the neck region wide; female didelphic-amphidelphic; pars proximalis vaginae violin-shaped. Males were not found. SEM observations of the new species were made and a phylogenetic analysis of both the 18S rDNA and the D2-D3 region of 28S rDNA is presented.

A new species of the genus Eudorylaimus Andrássy, 1959 (Nematoda: (Dorylaimida: Qudsianematidae) associated with Picea crassifolia in China.

A new species, Eudorylaimus piceae n. sp., extracted from rhizosphere soil of Picea crassifolia from Inner Mongolia, China was identified. The new species is characterized by these combined characters: body length of 1.03-1.27 mm; lip region distinctly offset; odontostyle 20-22 µm and 1.1-1.4 times the lip region diameter in length; odontophore 1.1-1.2 times the odontostyle length; basal expansion of pharynx occupying 42%-50.5% of the total neck length; genital system didelphic-amphidelphic; vulva transverse; vagina extending inwards 32%-43%; V value averaging more than 60; pars refringens vaginae with two trapezoidal sclerotizations and pars distalis vaginae weakly sclerotized; prerectum 72-107 µm long, 2.3-3.3 times the anal body diameter, and rectum 1-1.6 times the anal body diameter in length; tail conoid and bent ventrally, c' value 1.5-1.8 and males unknown. Phylogenetic analyses based on sequences of 18S small subunit rDNA and the D2-D3 expansion region of 28S rDNA are presented.

An efficient multi-stage fermentation strategy for the production of microbial oil rich in arachidonic acid in Mortierella alpina.

BACKGROUND: Fungal morphology and aeration play a significant role in the growth process of Mortierella alpina. The production of microbial oil rich in arachidonic acid (ARA) in M. alpina was enhanced by using a multi-stage fermentation strategy which combined fed-batch culture with precise control of aeration and agitation rates at proper times. RESULTS: The fermentation period was divided into four stages according to the cultivation characteristics of M. alpina. The dissolved oxygen concentration was well suited for ARA biosynthesis. Moreover, the ultimate dry cell weight (DCW), lipid, and ARA yields obtained using this strategy reached 41.4, 22.2, 13.5 g/L, respectively. The respective values represent 14.8, 25.8, and 7.8% improvements over traditional fed-batch fermentation processes. CONCLUSIONS: This strategy provides promising control insights for the mass production of ARA-rich oil on an industrial scale. Pellet-like fungal morphology was transformed into rice-shaped particles which were beneficial for oxygen transfer and thus highly suitable for biomass accumulation.

Arabidopsis thaliana as a suitable model host for research on interactions between plant and foliar nematodes, parasites of plant shoot.

The rice white tip nematode (RWTN), Aphelenchoides besseyi and the chrysanthemum foliar nematode (CFN), Aphelenchoides ritzemabosi are migratory plant parasitic nematodes that infect the aboveground parts of plants. In this research, Arabidopsis thaliana was infected by RWTN and CFN under indoor aseptic cultivation, and the nematodes caused recognizable symptoms in the leaves. Furthermore, RWTN and CFN completed their life cycles and proliferated. Therefore, A. thaliana was identified as a new host of RWTN and CFN. The optimum inoculum concentration for RWTN and CFN was 100 nematodes/plantlet, and the optimum inoculum times were 21 and 24 days, respectively. For different RWTN populations, the pathogenicity and reproduction rates were different in the A. thaliana Col-0 ecotype and were positively correlated. The optimum A. thaliana ecotypes were Col-0 and WS, which were the most susceptible to RWTN and CFN, respectively. Additionally, RWTN was ectoparasitic and CFN was ecto- and endoparasitic in A. thaliana. The RWTN and CFN migrated from inoculated leaves to the entire plantlet, and the number of nematodes in different parts of A. thaliana was not correlated with distance from the inoculum point. This is a detailed study of the behavior and infection process of foliar nematodes on A. thaliana.

A new species of the genus Discolaimus Cobb, 1913 (Nematoda: Dorylaimida: Qudsianematidae) from Qinghai, China.

A new species of the family Qudsianematidae Jairajpuri, 1965 collected from soil from Qinghai Province, China is described as Discolaimus anemaqen n. sp. It is mainly characterized by having a disc-like lip region with six labial sectors separated by six Y-shaped radial grooves; amphid fovea an inverted-stirrup shape; odontostyle aperture 53-59% of its length; anterior part of pharynx with two swellings, basal part expanded gradually with a sheath of tissue visible ventrally and at the base; no groups of large cells observed in cardiac region; female genital system amphidelphic; tail dorsally convex, conoid, with flat ventral side and bluntly rounded terminus, and males not found. The new species is close to D. major Thorne, 1939, D. similis Thorne, 1939 and D. silvicolus Sauer & Annells, 1985 in most measurements, but can be differentiated from them by lip morphology, pharynx structure, body size, and tail shape. A key to the species of Discolaimus is also provided.

Pin Nematode Slow Decline of Anthurium andraeanum, a New Disease Caused by the Pin Nematode Paratylenchus shenzhenensis.

High population densities of the plant-parasitic nematode Paratylenchus shenzhenensis have been observed in association with stunted anthurium in Shenzhen, Guangdong Province, China. P. shenzhenensis is now recognized as a new pathogen that causes severe damage to anthurium. Commercial fields of anthurium infected by P. shenzhenensis present a patchy distribution of plants that are usually stunted and in decline and have yellowing leaves. Roots that are heavily infected by this nematode present brown, dark-brown, or black rot, and the entire root mass is often destroyed. In this study, a method of culturing P. shenzhenensis on carrot disks was established, and the effects of temperature and time on the reproduction rate (Rr = final number of nematodes/initial number of nematodes) of this nematode were assessed. The optimum temperature for culturing P. shenzhenensis on carrot disks is 25°C and, after inoculation with 20 females and 10 males at 25°C for 10 weeks, Rr reached 3,834. At the optimum temperature, a suitable extension culture time or an increase in initial inoculum density will improve the reproductive efficiency of P. shenzhenensis. Koch's postulates were fulfilled by inoculating P. shenzhenensis on the roots of anthurium and demonstrating the pathogenicity of the nematode. Histological analyses showed that P. shenzhenensis feed endoparasitically on the roots of anthurium; whole nematode bodies were observed in the outermost epidermal cells and root hairs, and the cell walls and middle lamellae were partially dissolved because of nematode migration and feeding.

Lipid Fraction and Intracellular Metabolite Analysis Reveal the Mechanism of Arachidonic Acid-Rich Oil Accumulation in the Aging Process of Mortierella alpina.

The mechanism of arachidonic acid (ARA) content increase during aging of Mortierella alpina was elucidated. Lipid fraction analysis showed that ARA content increased from 46.9% to 66.4% in the triacylglycerol (TAG) molecule, and ARA residue occupation increased in the majority of TAG molecules during the aging process. For the first time, intracellular metabolite analysis was conducted to reveal the pathways closely associated with ARA biosynthesis during aging. The main reason for the increased ARA content was not only at the expense of other fatty acids degradation but also at the expense of further ARA biosynthesis during aging. Furthermore, translocation played a vital role in ARA redistribution among the glycerol moiety, and mycelium did not die immediately with key pathways activated to maintain a relatively stable intracellular environment. This study lays a foundation for further improvement of ARA content in the oil product obtained from M. alpina.

Cathepsin B Cysteine Proteinase is Essential for the Development and Pathogenesis of the Plant Parasitic Nematode Radopholus similis.

Radopholus similis is an important plant parasitic nematode which severely harms many crops. Cathepsin B is present in a wide variety of organisms, and plays an important role in many parasites. Understanding cathepsin B of R. similis would allow us to find new targets and approaches for its control. In this study, we found that Rs-cb-1 mRNA was expressed in esophageal glands, intestines and gonads of females, testes of males, juveniles and eggs in R. similis. Rs-cb-1 expression was the highest in females, followed by juveniles and eggs, and was the lowest in males. The maximal enzyme activity of Rs-CB-1 was detected at pH 6.0 and 40 °C. Silencing of Rs-cb-1 using in vitro RNAi (Soaking with dsRNA in vitro) not only significantly inhibited the development and hatching of R. similis, but also greatly reduced its pathogenicity. Using in planta RNAi, we confirmed that Rs-cb-1 expression in nematodes were significantly suppressed and the resistance to R. similis was significantly improved in T2 generation transgenic tobacco plants expressing Rs-cb-1 dsRNA. The genetic effects of in planta RNAi-induced gene silencing could be maintained in the absence of dsRNA for at least two generations before being lost, which was not the case for the effects induced by in vitro RNAi. Overall, our results first indicate that Rs-cb-1 plays key roles in the development, hatching and pathogenesis of R. similis, and that in planta RNAi is an effective tool in studying gene function and genetic engineering of plant resistance to migratory plant parasitic nematodes.

Morphological and karyotypic differences within and among populations of Radopholussimilis.

Twenty populations of Radopholussimilis from three countries and different hosts (19 populations from ornamental plants and one population from ginger) were compared using morphological characters, morphometrics and karyotype between progeny from both single females and 30 females of each population. Morphological diversity existed in and among the populations, even within the progeny nematodes from single nematodes compared to that of 30 females. The labial disc shape, the number of head annuli, the terminated position of lateral lips, the number of genital papillae before cloacal apertures and female and male tail terminal shape showed variation. In addition, genital papillae arranged in a double row before cloacal apertures was first found in two ornamental populations. The karyotype of all the 20 populations was n = 5. Combining our results and previous studies, we support that Radopholuscitrophilus is a synonym of Radopholussimilis, and that it is not possible to distinguish physiological races or pathotypes of Radopholussimilis according to morphological characters or karyotype.

Efficient arachidonic acid-rich oil production by Mortierella alpina through a repeated fed-batch fermentation strategy.

Arachidonic acid (ARA)-rich oil production by Mortierella alpina is a long fermentation period needed process due to the low growth rate of the filamentous fungus used. This causes the low productivity of ARA-rich oil and hinders its industrial mass scale production. In the present study, different fed-batch strategies were conducted to shorten the fermentation period. The result showed that compared with the batch culture, the fermentation period was shortened from 7days to 5days with the productivity of ARA-rich oil increased from 0.9g/(L·d) to 1.3g/(L·d) by using the fed-batch fermentation strategy. Furthermore, repeated fed-batch fermentation strategy was adopted to achieve the purpose of continuous production. By using this strategy, the fermentation period was shortened from 40days to 26days in a four cycle repeated fed-batch fermentation. This strategy proved to be convenient and economical for ARA-rich oil commercial production process.