scholarly journals Biology and predatory attributes of a diplogasterid nematode, Fictor composticola Khan et al., 2008

2015 ◽  
Vol 52 (1) ◽  
pp. 50-57 ◽  
Author(s):  
H. K. Bajaj ◽  
R. S. Kanwar

Summary Biology of Fictor composticola has been studied on Aphelenchus avenae in vitro. It reproduces by amphimixis, embryonic development is completed in 24 - 27 h and life cycle in 3 - 4 days. Fusion of sperm and egg pronuclei occurs in the uteri. Pulsation of median oesophageal bulb and pressing of lips against egg shell is seen just prior to hatching but teeth seem to play no role in this process. No moulting occurs inside the egg shell and the first stage juvenile hatches out. Female and male undergo mating upon addition of water in the culture plates and continue to swim in copula for a considerable time. A female lays 1.6 - 4.0 eggs in 24 h while feeding upon A. radicicolus. Predation and reproduction is affected by the temperature and 25 - 35 °C is the optimum range for these phenomena. Process of feeding as recorded with a CCTV attached to a compound microscope is described. F. composticola engulfs small preys; sucks the intestinal contents while holding them or cuts the body wall of large-sized preys and then feeds on prolapsed organs. Two sexes differ in their efficiencies of predation, a female on an average kills 53 A. avenae as compared to 11 by a male in 24 h. F. composticola feeds and reproduces on mycophagous nematodes and juveniles of root- knot, cyst and citrus nematodes but does not prey upon adult nematodes having coarsely annulated cuticle. Cannibalism in this species is also observed. F. composticola and Seinura paratenuicaudata prey upon each other. Biocontrol potential of F. composticola for managing nematode problems in button mushroom and agricultural crops has also been discussed.

Parasitology ◽  
2007 ◽  
Vol 135 (1) ◽  
pp. 125-130 ◽  
Author(s):  
V. M. BOWLES ◽  
A. R. YOUNG ◽  
S. C. BARKER

SUMMARYTo investigate the biochemical components of egg-hatch in the body louse, Pediculus humanus, egg-shell-washings (ESW) were collected during the first 2 h post-hatching and analysed by gelatin SDS-PAGE. These ESW contained proteases with molecular mass in the range of 25–100 kDa; the most abundant proteases were ~25 kDa. The 3 main regions of protease activity in the one-dimensional gelatin SDS-PAGE gels resolved to at least 23 distinct regions of protease activity when analysed by two-dimensional gelatin SDS-PAGE, with iso-electric points spread over the entire 3 to 10 pH range. Mechanistic characterization indicated that the ESW contained proteases of the metallo-class, inhibited by both 1,10-phenanthroline and EDTA. Several protease inhibitors were tested for their ability to inhibit louse egg-hatch in vitro. The metalloprotease inhibitor 1,10-phenanthroline and the aminopeptidase inhibitor bestatin significantly inhibited (P<0·05) louse egg-hatch (100% and 58%, respectively). The presence of metalloproteases at the time of egg-hatch and the inhibition of egg-hatch in P. humanus by metalloprotease inhibitors suggests a crucial role for these proteases in the hatching of this medically important parasite.


1988 ◽  
Vol 66 (2) ◽  
pp. 289-295 ◽  
Author(s):  
Barbara Skaling ◽  
B. M. MacKinnon

The histology, ultrastructure, and absorptive capabilities of the body wall and intestine of the juvenile stages of Nectonema sp. (Nematomorpha: Nectonematoidea) that parasitize the shrimp Pandalus montagui in Passamaquoddy Bay, New Brunswick, were examined using histological, histochemical, ultrastructural, and in vitro labeling techniques. The body wall consists of a multilayered cuticle that rests on, and is produced by, a thin cellular hypodermis. The intestinal tract consists of a minute mouth, a cuticularized oesophagus, and a blind-ending intestine consisting of a lumen surrounded at different places by two, three, or four elongated cells. These cells consists of a maximum of two "absorptive" cells with microvillar luminal surfaces, and a maximum of two "secretory" cells, which contain numerous electron-dense granules. Acid and alkaline phosphatases and nonspecific esterases were detected in the outer layers of the body wall (cuticle and hypodermis) and in the intestinal cells. Such enzymes appear to be related to absorption of nutrient substances. Autoradiography experiments using [3H]leucine showed that following incubation in [3H]leucine-labeled seawater, leucine was concentrated in the hypodermis and the intestinal cells. Similar results were obtained when worms were incubated first in [3H]leucine-labeled seawater and then chased in nonlabeled L-leucine. Uptake of [3H]leucine was inhibited by L-leucine when worms were incubated in a seawater solution of [3H]leucine and excess L-leucine. In vitro absorption of [3H]leucine provides evidence that a carrier-mediated transport system operates across both the cuticle and the intestine of Nectonema sp.


Nematology ◽  
1999 ◽  
Vol 1 (2) ◽  
pp. 131-139 ◽  
Author(s):  
Rita Holland ◽  
Keith Williams ◽  
Alamgir Khan

AbstractThe in vitro interaction of Paecilomyces lilacinus strain 251 with eggs, 3rd and 4th stage juveniles and adult females of Meloidogyne javanica was studied. Eggs of all stages, including those containing unhatched juveniles, were infected by P. lilacinus. Infection of eggs occurred following flattening of hyphae to the egg surface and formation of appressoria. Sometimes these occurred within extensive networks of hyphae of the egg surface. Hyphae later grew out of the egg to continue growing or form conidiophores. Third and 4th stage juveniles and adult females were readily infected, with hyphae and conidiophores penetrating the body wall. Die Infektion von Meloidogyne javanica durch Paecilomyces lilacinus - Es wurden die in vitro auftretenden Wechselwirkungen zwischen Paecilomyces lilacinus Stamm 251 und den Eiern, J3, J4 und adulten Weibchen von Meloidogyne javanica untersucht. Eier wurden in allen Stadien von P. lilacinus infiziert einschliesslich der ungeschlupfte J2 enthaltenden Eier. Die Infektion erfolgte anschliessend an eine Abflachung von Hyphen auf der Eioberflache und eine Appressorienbildung. Manchmal erschienen diese innerhalb eines ausgedehnten Netzwerkes von Hyphen auf der Eioberflache. Spater wuchsen Hyphen aus dem Ei heraus, wuchsen weiter oder bildeten Konidiophoren. Juvenile des dritten oder vierten Stadiums und adulte Weibchen wurden ohne weiteres befallen, wobei Hyphen und Konidiophoren durch die Korperwand drangen.


2011 ◽  
Vol 7 (6) ◽  
pp. 885-888 ◽  
Author(s):  
Shannon P. Gerry ◽  
David J. Ellerby

The body wall muscles of sanguivorous leeches power mechanically diverse behaviours: suction feeding, crawling and swimming. These require longitudinal muscle to exert force over an extremely large length range, from 145 to 46 per cent of the mean segmental swimming length. Previous data, however, suggest that leech body wall muscle has limited capacity for force production when elongated. Serotonin (5-HT) alters the passive properties of the body wall and stimulates feeding. We hypothesized that 5-HT may also have a role in allowing force production in elongated muscle by changing the shape of the length–tension relationship (LTR). LTRs were measured from longitudinal muscle strips in vitro in physiological saline with and without the presence of 10 µM 5-HT. The LTR was much broader than previously measured for leech muscle. Rather than shifting the LTR, 5-HT reduced passive muscle tonus and increased active stress at all lengths. In addition to modulating leech behaviour and passive mechanical properties, 5-HT probably enhances muscle force and work production during locomotion and feeding.


1965 ◽  
Vol 43 (5) ◽  
pp. 689-700 ◽  
Author(s):  
K. A. Wright

The histology of the oesophageal region of the plant parasitic nematode Xiphinema index Thorne and Allen, 1950 has been studied in cross sections of KMnO4-fixed nematodes. The stoma consists of cuticle, which is of different types anterior and posterior to the guide ring, and its underlying hypodermis. The latter tissue is connected through the dorsal, ventral, and lateral hypodermal chords to the interchordal hypodermis of the body wall. It is suggested that the dilator buccae muscles may act to close the stoma around the odontostyle. Stylet retractor muscles are identified. Observations on the guide ring complex support the interpretation that the guide sheath is an eversible portion of the posterior stoma cuticle. The odontostyle is embedded within the tip of the extension, which appears to be similar in composition and continuous with the posterior stoma cuticle. Cellular circumoesophageal membranes occur around the oesophagus. Those surrounding the oesophageal bulb are modified as muscle cells.


2011 ◽  
Vol 22 (13) ◽  
pp. 2258-2269 ◽  
Author(s):  
Shoichiro Ono ◽  
Kazumi Nomura ◽  
Sadae Hitosugi ◽  
Domena K. Tu ◽  
Jocelyn A. Lee ◽  
...  

Disassembly of actin filaments by actin-depolymerizing factor (ADF)/cofilin and actin-interacting protein 1 (AIP1) is a conserved mechanism to promote reorganization of the actin cytoskeleton. We previously reported that unc-78, an AIP1 gene in the nematode Caenorhabditis elegans, is required for organized assembly of sarcomeric actin filaments in the body wall muscle. unc-78 functions in larval and adult muscle, and an unc-78–null mutant is homozygous viable and shows only weak phenotypes in embryos. Here we report that a second AIP1 gene, aipl-1 (AIP1-like gene-1), has overlapping function with unc-78, and that depletion of the two AIP1 isoforms causes embryonic lethality. A single aipl-1–null mutation did not cause a detectable phenotype. However, depletion of both unc-78 and aipl-1 arrested development at late embryonic stages due to severe disorganization of sarcomeric actin filaments in body wall muscle. In vitro, both AIPL-1 and UNC-78 preferentially cooperated with UNC-60B, a muscle-specific ADF/cofilin isoform, in actin filament disassembly but not with UNC-60A, a nonmuscle ADF/cofilin. AIPL-1 is expressed in embryonic muscle, and forced expression of AIPL-1 in adult muscle compensated for the function of UNC-78. Thus our results suggest that enhancement of actin filament disassembly by ADF/cofilin and AIP1 proteins is critical for embryogenesis.


2020 ◽  
Author(s):  
Shoichiro Ono ◽  
Kanako Ono

AbstractMulticellular organisms have multiple genes encoding calponins and calponin-related proteins, and some of these are known to regulate actin cytoskeletal dynamics and contractility. However, functional similarities and differences among these proteins are largely unknown. In the nematode Caenorhabditis elegans, UNC-87 is a calponin-related protein with seven calponin-like (CLIK) motifs and is required for maintenance of contractile apparatuses in muscle cells. Here, we report that CLIK-1, another calponin-related protein that also contains seven CLIK motifs, has an overlapping function with UNC-87 to maintain actin cytoskeletal integrity in vivo and has both common and different actin-regulatory activities in vitro. CLIK-1 is predominantly expressed in the body wall muscle and somatic gonad, where UNC-87 is also expressed. unc-87 mutation causes cytoskeletal defects in the body wall muscle and somatic gonad, whereas clik-1 depletion alone causes no detectable phenotypes. However, simultaneous depletion of clik-1 and unc-87 caused sterility due to ovulation failure by severely affecting the contractile actin networks in the myoepithelial sheath of the somatic gonad. In vitro, UNC-87 bundles actin filaments. However, CLIK-1 binds to actin filaments without bundling them and is antagonistic to UNC-87 in filament bundling. UNC-87 and CLIK-1 share common functions to inhibit cofilin binding and allow tropomyosin binding to actin filaments, suggesting that both proteins stabilize actin filaments. Thus, partially redundant functions of UNC-87 and CLIK-1 in ovulation is likely mediated by their common actin-regulatory activities, but their distinct activities in actin bundling suggest that they also have different biological functions.


2021 ◽  
Vol 12 (6) ◽  
pp. 751-758
Author(s):  
Nishi Keshari ◽  
◽  
R. S. Kanwar ◽  

In this study, the predation behaviour of male and female predatory nematode, Fictor composticola, was studied on five prey nematode species, Aphelenchus avenae, Aphelenchoides swarupi, Ditylenchus myceliophagus, Bursilla sp. and Panagrolaimus sp., found in the white button mushroom compost. The period of the study is of six months. The data recorded on number of encounters, part of the body of prey attacked, stage of the prey attacked, duration of feeding etc. The strike rate and prey susceptibility were calculated. The average number of encounters on all the five preys done by female F. composticola was 3.0 and that of the male was 6.0. Male F. composticola had more number of encounters on the prey nematode species than the females. Both the sexes preferred juvenile stages over adults as prey. The most attacked part by both females and males predator, was the posterior part of the prey body. In 80% of cases, female predators fed on the first encountered prey while males attacked the first encountered prey in 30% of cases only. The strike rate of female F. composticola was more (78.6%) than the male (48.2%). Mycophagous nematodes were more susceptible to predator’s attack than the microbivorous nematodes. The strike rate of the predator on different prey nematode species was found more on mycophagous nematodes than on microbivorous nematodes and minimum on Panagrolaimus sp. The average feeding duration of female F. composticola was 8 min and 31 sec and in the case of males it was 4 min and 11 sec.


Metabolites ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 69
Author(s):  
Mahesh Raj Nepal ◽  
Ki Sun Jeong ◽  
Geon Ho Kim ◽  
Dong Ho Cha ◽  
Mi Jeong Kang ◽  
...  

Alteration in the number and composition of intestinal microbiota affects the metabolism of several xenobiotics. Gastrodin, isolated from Gastrodia elata, is prone to be hydrolyzed by intestinal microbiota. In the present study, the role of intestinal microbiota in gastrodin metabolism was investigated in vitro and in vivo. Gastrodin was incubated in an anaerobic condition with intestinal contents prepared from vehicle- and antibiotics-treated rats and the disappearance of gastrodin and formation of 4-hydroxybenzyl alcohol (4-HBA) was measured by liquid chromatography coupled to mass spectroscopy (LC-MS/MS). The results showed that almost all gastrodin incubated with control intestinal contents was metabolized to its aglycone in time- and concentration-dependent manners. In contrast, much less formation of 4-HBA was detected in intestinal contents from antibiotics-treated rats. Subsequently, in vivo pharmacokinetic study revealed that the antibiotic pretreatment of rats significantly affected the metabolism of gastrodin to 4-HBA. When administered orally, gastrodin was rapidly absorbed rapidly into plasma, metabolized to 4-HBA, and disappeared from the body within six hours. Interestingly, the pharmacokinetic parameters of 4-HBA were changed remarkably in antibiotics-treated rats, compared to control rats. The results clearly indicated that the antibiotics treatment of rats suppressed the ability of intestinal microbiota to metabolize gastrodin to 4-HBA and that, thereby, the pharmacodynamic action was significantly modulated.


2020 ◽  
Vol 295 (34) ◽  
pp. 12014-12027
Author(s):  
Shoichiro Ono ◽  
Kanako Ono

Multicellular organisms have multiple genes encoding calponins and calponin-related proteins, some of which are known to regulate actin cytoskeletal dynamics and contractility. However, the functional similarities and differences among these proteins are largely unknown. In the nematode Caenorhabditis elegans, UNC-87 is a calponin-related protein with seven calponin-like (CLIK) motifs and is required for maintenance of contractile apparatuses in muscle cells. Here, we report that CLIK-1, another calponin-related protein that also contains seven CLIK motifs, functionally overlaps with UNC-87 in maintaining actin cytoskeletal integrity in vivo and has both common and different actin-regulatory activities in vitro. We found that CLIK-1 is predominantly expressed in the body wall muscle and somatic gonad in which UNC-87 is also expressed. unc-87 mutation caused cytoskeletal defects in the body wall muscle and somatic gonad, whereas clik-1 depletion alone caused no detectable phenotypes. However, simultaneous clik-1 and unc-87 depletion caused sterility because of ovulation failure by severely affecting the contractile actin networks in the myoepithelial sheath of the somatic gonad. In vitro, UNC-87 bundled actin filaments, whereas CLIK-1 bound to actin filaments without bundling them and antagonized UNC-87–mediated filament bundling. We noticed that UNC-87 and CLIK-1 share common functions that inhibit cofilin binding and allow tropomyosin binding to actin filaments, suggesting that both proteins stabilize actin filaments. In conclusion, partially redundant functions of UNC-87 and CLIK-1 in ovulation are likely mediated by their common actin-regulatory activities, but their distinct actin-bundling activities suggest that they also have different biological functions.


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