Coprinus comatus Damages Nematode Cuticles Mechanically with Spiny Balls and Produces Potent Toxins To Immobilize Nematodes

ABSTRACT We reported recently a unique fungal structure, called the spiny ball, on the vegetative hyphae of Coprinus comatus (O. F. Mï¿½ll.:Fr.) Pers. Although some observations regarding the role of this structure were presented, its function remained largely unknown. In this study, we showed that purified (isolated and washed) spiny balls could immobilize and kill the free-living nematode Panagrellus redivivus Goodey highly efficiently. Scanning electron microscopy studies illustrated that the spiny structure damaged the nematode cuticle, suggesting the presence of a mechanical force during the process of nematode immobilization. Severe injuries on nematode cuticles caused the leakage of inner materials of the nematodes. When these structures were ground in liquid nitrogen, their killing efficacy against nematodes was lost, indicating that the shape and the complete structure of the spiny balls are indispensable for their function. However, extraction with organic solvents never lowered their activity against P. redivivus, and the extracts showed no obvious effect on the nematode. We also investigated whether C. comatus was able to produce toxins which would aid in the immobilization of nematodes. In total, we identified seven toxins from C. comatus that showed activity to immobilize the nematodes P. redivivus and Meloidogyne incognita (Kofoid et White) Chitwood. The chemical structures of these toxins were identified with nuclear magnetic resonance, mass spectrometry, infrared, and UV spectrum analysis. Two compounds were found to be novel. The toxins found in C. comatus are O-containing heterocyclic compounds.

Download Full-text

The investigation of nematocidal activity in Stenotrophomonas maltophilia G2 and characterization of a novel virulence serine protease

Canadian Journal of Microbiology ◽

10.1139/w09-045 ◽

2009 ◽

Vol 55 (8) ◽

pp. 934-942 ◽

Cited By ~ 23

Author(s):

Xiaowei Huang ◽

Junwei Liu ◽

Junmei Ding ◽

Qiusheng He ◽

Rui Xiong ◽

...

Keyword(s):

Serine Protease ◽

Serine Proteases ◽

Stenotrophomonas Maltophilia ◽

Bursaphelenchus Xylophilus ◽

Panagrellus Redivivus ◽

Bacterial Culture Supernatant ◽

Free Living Nematode ◽

Nematocidal Activity ◽

Nematode Cuticle

The Gram-negative bacterium Stenotrophomonas maltophilia G2 was isolated from a soil sample and was found to have high nematotoxic activity against a free-living nematode, Panagrellus redivivus, and a plant-parasitic nematode, Bursaphelenchus xylophilus . The analysis of virulence factors revealed that although the small molecular metabolites participated in nematode killing, the crude extracellular protein extract from the bacterial culture supernatant contributed significantly to its nematocidal activity. An extracellular protease was purified by chromatography, and its effects on degrading purified nematode cuticle and killing living nematodes were confirmed experimentally. Characterization of this purified protease revealed that the application of phenylmethylsulphonyl fluoride, an inhibitor of serine proteases, could completely abolish its proteolytic activity. The results from N-terminal amino acid sequencing showed no similarity with any known serine protease in S. maltophilia, suggesting a novel virulence serine protease was obtained. Our study is the first to show the nematocidal activity of S. maltophilia, and we identified a novel serine protease as an important pathogenicity factor.

Download Full-text

A novel putative microtubule-associated protein is involved in arbuscule development during arbuscular mycorrhiza formation

Plant and Cell Physiology ◽

10.1093/pcp/pcaa159 ◽

2021 ◽

Author(s):

Tania Ho-Plágaro ◽

Raúl Huertas ◽

María I Tamayo-Navarrete ◽

Elison Blancaflor ◽

Nuria Gavara ◽

...

Keyword(s):

Plant Root ◽

Arbuscular Mycorrhizal ◽

Host Cells ◽

Root Cells ◽

Filament Dynamics ◽

Fungal Structure ◽

Genes Encoding ◽

Associated Proteins ◽

Mycorrhizal Development

Abstract The formation of arbuscular mycorrhizal (AM) symbiosis requires plant root host cells to undergo major structural and functional reprogramming in order to house the highly branched AM fungal structure for the reciprocal exchange of nutrients. These morphological modifications are associated with cytoskeleton remodelling. However, molecular bases and the role of microtubules (MTs) and actin filament dynamics during AM formation are largely unknown. In this study, the tomato tsb gene, belonging to a Solanaceae group of genes encoding MT-associated proteins for pollen development, was found to be highly expressed in root cells containing arbuscules. At earlier stages of mycorrhizal development, tsb overexpression enhanced the formation of highly developed and transcriptionally active arbuscules, while tsb silencing hampers the formation of mature arbuscules and represses arbuscule functionality. However, at later stages of mycorrhizal colonization, tsb OE roots accumulate fully developed transcriptionally inactive arbuscules, suggesting that the collapse and turnover of arbuscules might be impaired by TSB accumulation. Imaging analysis of the MT cytoskeleton in cortex root cells overexpressing tsb revealed that TSB is involved in MT-bundling. Taken together, our results provide unprecedented insights into the role of novel MT-associated protein in MT rearrangements throughout the different stages of the arbuscule life cycle.

Download Full-text

The zona incerta modulates spontaneous spike-wave discharges in the rat

Journal of Neurophysiology ◽

10.1152/jn.00750.2011 ◽

2013 ◽

Vol 109 (10) ◽

pp. 2505-2516 ◽

Cited By ~ 8

Author(s):

Fu-Zen Shaw ◽

Yi-Fang Liao ◽

Ruei-Feng Chen ◽

Yu-Hsing Huang ◽

Rick C. S. Lin

Keyword(s):

Functional Role ◽

Significant Inhibition ◽

Zona Incerta ◽

Obvious Effect ◽

Spike Wave Discharges ◽

Long Evans ◽

Oscillation Frequencies ◽

Spike Wave ◽

Stimulation Of

The contribution of the zona incerta (ZI) of the thalamus on spike-wave discharges (SWDs) was investigated. Chronic recordings of bilateral cortices, bilateral vibrissa muscle, and unilateral ZI were performed in Long-Evans rats to examine the functional role of SWDs. Rhythmic ZI activity appeared at the beginning of SWD and was accompanied by higher-oscillation frequencies and larger spike magnitudes. Bilateral lidocaine injections into the mystacial pads led to a decreased oscillation frequency of SWDs, but the phenomenon of ZI-related spike magnitude enhancement was preserved. Moreover, 800-Hz ZI microstimulation terminates most of the SWDs and whisker twitching (WT; >80%). In contrast, 200-Hz ZI microstimulation selectively stops WTs but not SWDs. Stimulation of the thalamic ventroposteriomedial nucleus showed no obvious effect on terminating SWDs. A unilateral ZI lesion resulted in a significant reduction of 7- to 12-Hz power of both the ipsilateral cortical and contralateral vibrissae muscle activities during SWDs. Intraincertal microinfusion of muscimol showed a significant inhibition on SWDs. Our present data suggest that the ZI actively modulates the SWD magnitude and WT behavior.

Download Full-text

The Role of Internal Control in Firms’ Coping with the Impact of the COVID-19 Pandemic: Evidence from China

Sustainability ◽

10.3390/su13116294 ◽

2021 ◽

Vol 13 (11) ◽

pp. 6294

Author(s):

Peiqing Zhu ◽

Jianbo Song

Keyword(s):

Internal Control ◽

Manufacturing Industry ◽

Firm Heterogeneity ◽

Negative Impact ◽

Risk Prevention ◽

High Tech ◽

Obvious Effect ◽

The Difference ◽

The Impact

Internal control plays a role in risk prevention for firms when dealing with serious emergencies, which ensures the sustainable development of firms during a crisis. Based on the rapid outbreak of COVID-19 in China, this paper empirically tests whether internal control alleviates the negative impact of the pandemic on firm performance. Using a sample of Chinese listed firms from the first quarter of 2019 to the third quarter of 2020 and employing the difference-in-difference (DID) method, we find that the firms with a higher quality of internal control achieve better financial performance during the pandemic period; the more serious the pandemic is, the more obvious effect internal control plays. Furthermore, we consider the industry heterogeneity and firm heterogeneity of the risk resistance effect of internal control. In the manufacturing industry, which is a “disaster zone” of the pandemic, and the non-high-tech industry with a low degree of digitization, internal control can play a more important role in firms’ performance. Moreover, for state-owned enterprises, and firms with strong financing constraints, the role of internal control is more prominent. The above results provide empirical evidence for the risk prevention function of internal control and shed new light on the measures for firms to resist emergencies in the future.

Download Full-text

The demise of the Platonic worm

Nematology ◽

10.1163/156854100508917 ◽

2000 ◽

Vol 2 (1) ◽

pp. 71-79 ◽

Cited By ~ 7

Author(s):

Armand Leroi ◽

Scott Emmons ◽

Ana Cunha ◽

Ricardo B.R. Azevedo

Keyword(s):

Caenorhabditis Elegans ◽

Nematode Species ◽

Cell Number ◽

Cell Lineages ◽

Panagrellus Redivivus ◽

Seam Cell ◽

Nous Montrons ◽

Adult Cell ◽

Free Living Nematode ◽

Nuclear Number

AbstractNematodes are generally considered to have an adult cell number that does not vary among wildtype individuals as a consequence of invariant cell lineages (eutely). However, there is extensive evidence that at least some cell lineages can be variable in nematodes. In a comparative study of 13 free-living nematode species, we have shown that the adult epidermis of most species contained variable numbers of nuclei and that this variance was positively correlated with mean epidermal nuclear number. Here we present simulations of the lateral seam cell lineages of four species and show that variance in cell number is influenced by lineage topology, as well as by the frequency of lineage variants. We show that the epidermal variability of Panagrellus redivivus cannot be accounted for by the complexity of its lineage, but requires higher levels of lineage variability than are found in Caenorhabditis elegans, Oscheius myriophila and Rhabditella octopleura. Our findings suggest that many nematodes may have tissues composed of indeterminate numbers of cells formed from variable lineages and, as such, resemble other metazoans. Les nématodes sont généralement considérés comme ayant un nombre de cellules invariable chez les individus de type sauvage, conséquence d’un lignage cellulaire fixe (eutélie). Cependant, il est d’évidence qu’au moins certains des lignages cellulaires peuvent varier chez les nématodes. Dans une étude comparative portant sur 13 espèces de nématodes libres, nous avions montré que l’épiderme de la plupart de ces espèces comportait un nombre variable de noyaux et que cette variabilité était corrélée positivement avec le nombre de noyaux épidermiques. Nous présentons ici des simulations des lignages cellulaires de la suture latérale de quatre espèces et démontrons que le nombre de cellules est influencé tant par la topologie du lignage que par la fréquence des variants de ce lignage. Nous montrons que la variabilité de l’épiderme de Panagrellus redivivus ne peut être mise au compte de la complexité de son lignage, mais demande des niveaux élevés de variabilité de ce lignage, tels ceux trouvés chez Caenorhabditis elegans, Oscheius myriophila et Rhabditella octopleura. Nos observations suggèrent que nombre de nématodes possèdent des tissus composés d’un nombre indéterminé de cellules dérivant de lignages variables et, de ce fait, ressemblent aux autres metazoaires.

Download Full-text

Nematode Hsp90: highly conserved but functionally diverse

Parasitology ◽

10.1017/s0031182014000304 ◽

2014 ◽

Vol 141 (9) ◽

pp. 1203-1215 ◽

Cited By ~ 4

Author(s):

VICTORIA GILLAN ◽

EILEEN DEVANEY

Keyword(s):

Life Cycle ◽

Heat Shock Protein 90 ◽

Ecological Niches ◽

Actual Number ◽

Host Organism ◽

Free Living ◽

Parasitic Species ◽

Free Living Nematode ◽

Functionally Diverse

SUMMARYNematodes are amongst the most successful and abundant organisms on the planet with approximately 30 000 species described, although the actual number of species is estimated to be one million or more. Despite sharing a relatively simple and invariant body plan, there is considerable diversity within the phylum. Nematodes have evolved to colonize most ecological niches, and can be free-living or can parasitize plants or animals to the detriment of the host organism. In this review we consider the role of heat shock protein 90 (Hsp90) in the nematode life cycle. We describe studies on Hsp90 in the free-living nematode Caenorhabditis elegans and comparative work on the parasitic species Brugia pahangi, and consider whether a dependence upon Hsp90 can be exploited for the control of parasitic species.

Download Full-text

Development of a low-cost technology for mass production of the free-living nematode Panagrellus redivivus as an alternative live food for first feeding fish larvae

Applied Microbiology and Biotechnology ◽

10.1007/s00253-002-1178-2 ◽

2003 ◽

Vol 60 (5) ◽

pp. 556-559 ◽

Cited By ~ 18

Author(s):

M. Ricci ◽

A. Fifi ◽

A. Ragni ◽

C. Schlechtriem ◽

U. Focken

Keyword(s):

Mass Production ◽

Fish Larvae ◽

Low Cost ◽

Live Food ◽

Free Living ◽

First Feeding ◽

Panagrellus Redivivus ◽

Free Living Nematode

Download Full-text

Molecular cloning and characterization of ornithine decarboxylase cDNA of the nematode Panagrellus redivivus

Biochemical Journal ◽

10.1042/bj3080635 ◽

1995 ◽

Vol 308 (2) ◽

pp. 635-640 ◽

Cited By ~ 8

Author(s):

H von Besser ◽

G Niemann ◽

B Domdey ◽

R D Walter

Keyword(s):

Amino Acids ◽

Active Sites ◽

Cdna Clones ◽

Degenerate Primers ◽

Calculated Molecular Mass ◽

Panagrellus Redivivus ◽

Free Living Nematode ◽

Mixed Stage ◽

Conserved Amino Acids

In a PCR with degenerate primers encoding highly conserved amino acids within ornithine decarboxylases (ODCs) of several organisms, a fragment of the ODC gene of the free-living nematode Panagrellus redivivus was isolated. Northern blot analysis revealed a single 1.7 kb transcript in a mixed-stage population of animals. From this RNA source, a cDNA library was constructed and screened with the PCR fragment. Several cDNA clones were isolated, one of which encodes the complete 435-amino-acid ODC enzyme with a calculated molecular mass of 47.1 kDa. The P. redivivus ODC possesses 126 of the 136 highly conserved amino acids in the enzymes from fungi, invertebrates and vertebrates. Functional amino acids are conserved, suggesting that the two active sites of the P. redivivus ODC are formed at the interface of a homodimer, as described for mammalian ODCs.

Download Full-text

Acanthocytes of Stropharia rugosoannulata Function as a Nematode-Attacking Device

Applied and Environmental Microbiology ◽

10.1128/aem.72.4.2982-2987.2006 ◽

2006 ◽

Vol 72 (4) ◽

pp. 2982-2987 ◽

Cited By ~ 29

Author(s):

Hong Luo ◽

Xuan Li ◽

Guohong Li ◽

Yanbo Pan ◽

Keqin Zhang

Keyword(s):

Bursaphelenchus Xylophilus ◽

Mechanical Force ◽

Free Living ◽

Pine Wilt ◽

Panagrellus Redivivus ◽

Free Living Nematode

ABSTRACT Efficient killing of nematodes by Stropharia rugosoannulata Farlow ex Murrill cultures was observed. This fungus showed the ability to immobilize the free-living nematode Panagrellus redivivus Goodey within minutes and to immobilize the pine wilt nematode Bursaphelenchus xylophilus (Steiner & Buhrer) Nickle within hours on agar plates. Moreover, P. redivivus worms were completely degraded by the fungus within 24 to 48 h. The cultures of S. rugosoannulata studied shared the characteristic of abundantly producing cells with finger-like projections called acanthocytes. We showed that the nematode-attacking activity of this fungus is carried out by these spiny acanthocytes and that mechanical force is an important factor in the process. Furthermore, the growth and nematode-attacking activity of the fungus in soil were also determined, and our results suggest that acanthocytes are functional in soil.

Download Full-text