-
[
Dev Biol,
2022]
The microtubule cytoskeleton is critical for maintenance of long and long-lived neurons. The overlapping array of microtubules extends from the major site of synthesis in the cell body to the far reaches of axons and dendrites. New materials are transported from the cell body along these neuronal roads by motor proteins, and building blocks and information about the state of affairs in other parts of the cell are returned by motors moving in the opposite direction. As motor proteins walk only in one direction along microtubules, the combination of correct motor and correctly oriented microtubules is essential for moving cargoes in the right direction. In this review, we focus on how microtubule polarity is established and maintained in neurons. At first thought, it seems that figuring out how microtubules are organized in neurons should be simple. After all, microtubules are essentially sticks with a slow-growing minus end and faster-growing plus end, and arranging sticks within the constrained narrow tubes of axons and dendrites should be straightforward. It is therefore quite surprising how many mechanisms contribute to making sure they are arranged in the correct polarity. Some of these mechanisms operate to generate plus-end-out polarity of axons, and others control mixed or minus-end-out dendrites.
-
[
Mol Biol Cell,
2002]
The endoplasmic reticulum (ER) is divided into rough and smooth domains (RER and SER). The two domains share most proteins, but RER is enriched in some membrane proteins by an unknown mechanism. We studied RER protein targeting by expressing fluorescent protein fusions to ER membrane proteins in Caenorhabditis elegans. In several cell types RER and general ER proteins colocalized, but in neurons RER proteins were concentrated in the cell body, whereas general ER proteins were also found in neurites. Surprisingly RER membrane proteins diffused rapidly within the cell body, indicating they are not localized by immobilization. Ribosomes were also concentrated in the cell body, suggesting they may be in part responsible for targeting RER membrane proteins.
-
[
2011]
The authors note that in the Materials and Methods under the section Actin Pelleting Assay, the 10 stock concentration was listed instead of the 1 final working concentration for the polymerization and reaction buffers. The correct concentrations are as follows: polymerization buffer (20 mM Imidazole pH 7.0, 100 mM KCl, 2 mM MgCl2, 0.5 mM ATP, 1 mM EGTA) and reaction buffer (20 mM Imidazole pH 7.0, 150 mM NaCl, 2 mM MgCl2, 0.5 mM ATP, 1 mM EGTA, 1 mM DTT).
-
[
J Helminthol,
2017]
Urocanic acid (UCA) is known as a major chemoattractant for Strongyloides stercoralis infective third-stage larvae (L3). Since Brugia pahangi is a skin-penetrating parasitic nematode similar to S. stercoralis, UCA was expected to be a chemoattractant for B. pahangi L3. Thus, the chemoattractant activity of UCA for B. pahangi L3 was assessed. The chemotactic responses of B. pahangi L3 to UCA or acetic acid (CH3COOH) dissolved in amine solutions were assessed using an agar-plate assay. A test solution of 200 mm UCA dissolved in aqueous 270 mm tris(hydroxymethyl)aminomethane (Tris) significantly attracted B. pahangi L3 compared with deionized water (DW), while neither a solution of 200 mm UCA dissolved in aqueous 230 mm ammonia (NH3) nor 290 mm triethylamine (TEA) significantly attracted L3. Similarly, a test solution of 200 mm CH3COOH dissolved with 200 mm Tris significantly attracted L3, but neither a test solution of 200 mm CH3COOH plus 200 mm NH3 nor 200 mm TEA attracted L3. Furthermore, L3 were significantly attracted to 200 mm Tris alone, compared with DW, but avoided 200 mm NH3 and 200 mm TEA. Moreover, the chemoattractant activity of Tris for L3 was observed even at a low concentration of 25 mm, and it was observed in a mild alkaline condition but not in an acidic condition. The present study reveals that Tris is a potential chemoattractant for B. pahangi L3 while UCA is not. This finding will contribute to an understanding of the mechanisms of skin-penetrating infection of filarial L3.
-
[
Comp Biochem Physiol C,
1976]
1. The nematode C. elegans is attracted to pyridine. 2. The threshold is about 0.1 mM. 3. At concentrations above 1 mM the response weakens. 4. No indication of avoidance of high concentrations could be found.
-
[
J Nematol,
1970]
The effects of electric shock on Panagrellus redivivus adults and larvae and Meloidogyne incognita acrita larvae were studied. The nematodes were placed in tap water between two stainless steel electrodes, spaced 2 mm apart and cemented to a glass slide. Electric potentials of 1, 5, 10, 15, 20, 30, and 60 vdc/mm and vac/mm were applied for periods of 1 sec to 5 rain at 0.05 to 77 ma. The results demonstrated that ac or dc electric shocks as low as 5 v/mm for larvae and 10 v/mm for adults can be lethal. Some larvae and eggs within the body of P. redivivus females were not affected at 600 v/ram. Potentials of 20 and 60 vdc/mm for 2-sec stimulated hatch of Meloidogyne eggs.
-
[
MicroPubl Biol,
2023]
Exposure to the herbicide paraquat (PQ; 1,1'-dimethyl-4,4'-bipyridinium dichloride) affects the redox balance of the cell, an effect that can be restored by antioxidants, including N-acetyl cysteine (NAC). One hour of exposure to PQ (0 mM, 10 mM, 50 mM, or 100 mM) dose-dependently increased mortality in <i>Caenorhabditis elegans</i> after exposure (immediate toxicity), while this effect was more evident 24 hours thereafter (delayed toxicity). Importantly, pretreatment with NAC 0.5 mM for one hour partially prevented mortality in the immediate assay, while it had no effect in the delayed test, revealing the importance of long-term studies when evaluating toxicity.
-
[
Trop Med Parasitol,
1986]
Phosphoenolpyruvate carboxykinase, a rate-limiting enzyme at the branchpoint of phosphoenolpyruvate (PEP), was demonstrated in Onchocerca volvulus and O. gibsoni. The activity of PEP-carboxykinase from both filarial worms depends absolutely on the presence of divalent cations; in addition to Mg2+ the enzyme activity was strongly activated by Mn2+. The Michaelis constants for PEP, GDP and KHCO3 of the PEP-carboxykinase from O. volvulus were determined to be 0.16 mM, 0.15 mM and 20 mM, respectively; those of the enzyme from O. gibsoni were 0.16 mM, 0.13 mM and 12 mM. Quinolinate was found to be a potent inhibitor of the enzyme from both filarial worms. The inhibition constants were determined to be 11 microM and 15 microM for the enzyme from O. volvulus and O. gibsoni. It is suggested that the activity of PEP-carboxykinase, the initial enzyme of the alternate route from PEP to succinate, may be regulated by ATP-levels. The inhibition constants for ATP were determined to be 0.26 mM and 0.13 mM for the enzyme from O. volvulus and O. gibsoni.
-
[
Pharmacol Biochem Behav,
2011]
Nicotine induces profound behavioral responses in the model organism Caenorhabditis elegans. We tested the effect of a broad range of concentrations of nicotine (from 0.001 mM to 30 mM in nematode growth medium) on C. elegans locomotor behavior. We also followed the time-course influence on the sensitivity of C. elegans to nicotine (from 0 min to 300 min). A low concentration (0.001 mM) of this alkaloid causes a reduction of the speed of movement. By contrast, moderate concentrations (0.01 and 0.1 mM) induced acceleration of the mean speed of locomotion of C. elegans. High doses of nicotine (above 1 mM) induced slowing down of the movements and, finally, paralysis. Time-dependent analysis revealed that the stimulating effect of nicotine abolished the slowing down of C. elegans in control experiments after 30 min in the presence of 0.001, 0.1 and 10 mM nicotine. In the presence of 0.1 mM nicotine, the stimulation phase lasted up to 70 min. The evidence indicates that nicotine can have dual effects on the speed of locomotion, which is dependent on differences in its dosage and treatment time.
-
[
Worm Breeder's Gazette,
1998]
Correction: "The abstract entitled Control of Mitochondrial Morphology published in WBG Vol. 15 No. 1 contained an error. Worms were treated with 3 mM (not 100 mM) chloramphenicol to induce changes in mitochondrial morphology. Thanks to A.L. for spotting the error. M. Crawley & D. Adams