Li M et al. (2005) Dev Cell "Regulatory mutations of mir-48, a C. elegans let-7 family MicroRNA, cause developmental timing defects."

Lau NC, Rougvie AE, Jones-Rhoades MW, Li M, Bartel DP

[Dev Cell, 2005]

The C. elegans heterochronic genes program stage-specific temporal identities in multiple tissues during larval development. These genes include the first two miRNA-encoding genes discovered, lin-4 and let-7. We show that lin-58 alleles, identified as lin-4 suppressors, define another miRNA that controls developmental time. These alleles are unique in that they contain point mutations in a gene regulatory element of mir-48, a let-7 family member. mir-48 is expressed prematurely in lin-58 mutants, whereas expression of mir-241, another let-7 family member residing immediately upstream of mir-48, appears to be unaffected. A mir-48 transgene bearing a lin-58 point mutation causes strong precocious phenotypes in the hypodermis and vulva when expressed from multicopy arrays. mir-48::gfp fusions reveal expression in these tissues, and inclusion of a lin-58 mutation causes precocious and enhanced gfp expression. These results suggest that lin-58 alleles disrupt a repressor binding site that restricts the time of miR-48 action in wild-type animals.

Pang S et al. (2010) Lab Chip "Implementation of a color-capable optofluidic microscope on a RGB CMOS color sensor chip substrate."

DeModena J, Pang S, Yang C, Wang YM, Cui X, Sternberg P

[Lab Chip, 2010]

We report the implementation of a color-capable on-chip lensless microscope system, termed color optofluidic microscope (color OFM), and demonstrate imaging of double stained Caenorhabditis elegans with lacZ gene expression at a light intensity about 10 mW/cm(2).

Rand JB et al. (1985) J Neurochem "Properties and partial purification of choline acetyltransferase from the nematode Caenorhabditis elegans."

Russell RL, Rand JB

[J Neurochem, 1985]

We have stabilized and studied choline acetyltransferase from the nematode Caenorhabditis elegans. The enzyme is soluble, and two discrete forms were resolved by gel filtration. The larger of these two forms (MW approximately 154,000) was somewhat unstable and in the presence of 0.5 M NaI was converted to a form indistinguishable from the "native" small form (MW approximately 71,000). We have purified the small form of the enzyme greater than 3,300-fold by a combination of gel filtration, ion-exchange chromatography, and nucleotide affinity chromatography. The purified preparation has a measured specific activity of 3.74 mumol/min/mg protein, and is free of acetylcholinesterase and acetyl-CoA hydrolase activities. The Vmax of the purified enzyme is stimulated by NaCl, with half-maximal stimulation at 80 mM NaCl. The Km for each substrate is also affected by salt, but in different manners from each other and the Vmax; the kinetic parameter Vmax/Km thus changes significantly as a function of the salt concentration.

Lee JH et al. (2014) Biofouling "Thermoresponsive oligomers reduce Escherichia coli O157:H7 biofouling and virulence."

Kim YG, Cho MH, Lee J, Kim J, Lee JH, Cho HS, Kim SC

[Biofouling, 2014]

Thermoresponsive polymers have potential biomedical applications for drug delivery and tissue engineering. Here, two thermoresponsive oligomers were synthesized, viz. oligo(N-isopropylacrylamide) (ONIPAM) and oligo(N-vinylcaprolactam) (OVCL), and their anti-biofouling abilities investigated against enterohemorrhagic E. coli O157:H7, which produces Shiga-like toxins and forms biofilms. Biofilm formation (biofouling) is closely related to E. coli O157:H7 infection and constitutes a major mechanism of antimicrobial resistance. The synthetic OVCL (MW 679) and three commercial OVCLs (up to MW 54,000) at 30 g ml(-1) were found to inhibit biofouling by E. coli O157:H7 at 37 C by more than 80% without adversely affecting bacterial growth. The anti-biofouling activity of ONIPAM was weaker than that of OVCL. However, at 25 C, ONIPAM and OVCL did not affect E. coli O157:H7 biofouling. Transcriptional analysis showed that OVCL temperature-dependently downregulated curli genes in E. coli O157:H7, and this finding was in line with observed reductions in fimbriae production and biofouling. In addition, OVCL downregulated the Shiga-like toxin genes stx1 and stx2 in E. coli O157:H7 and attenuated its in vivo virulence in the nematode Caenorhabditis elegans. These results suggest that OVCL has potential use in antivirulence strategies against persistent E. coli O157:H7 infection.

de Pomerai DI et al. (2003) FEBS Lett "Microwave radiation can alter protein conformation without bulk heating."

Smith B, Archer DB, Smith T, Dawe A, Duce IR, Candido EPM, Jones D, North K, de Pomerai DI

[FEBS Lett, 2003]

Exposure to microwave radiation enhances the aggregation of bovine serum albumin in vitro in a time- and temperature-dependent manner. Microwave radiation also promotes amyloid fibril formation by bovine insulin at 60degreesC. These alterations in protein conformation are not accompanied by measurable temperature changes, consistent with estimates from field modelling of the specific absorbed radiation (15-20 mW kg(-1)). Limited denaturation of cellular proteins could explain our previous observation that modest heat-shock responses are induced by microwave exposure in Caenorhabditis elegans. We also show that heat-shock responses both to heat and microwaves are suppressed after RNA interference ablating heat-shock factor function.

He H et al. (2022) Opt Lett "890-nm-excited SHG and fluorescence imaging enabled by an all-fiber mode-locked laser."

He H, Zheng C, Lai HM, Qiao T, Ran Q, Ko H, Ren YX, Zhou M, Tsia KK, Wong KKY

[Opt Lett, 2022]

We demonstrate second-harmonic generation (SHG) microscopy excited by the ∼890-nm light frequency-doubled from a 137-fs, 19.4-MHz, and 300-mW all-fiber mode-locked laser centered at 1780 nm. The mode-locking at the 1.7-um window is realized by controlling the emission peak of the gain fiber, and uses the dispersion management technique to broaden the optical spectrum up to 30 nm. The spectrum is maintained during the amplification and the pulse is compressed by single-mode fibers. The SHG imaging performance is showcased on a mouse skull, leg, and tail. Two-photon fluorescence imaging is also demonstrated on C. elegans labeled with green and red fluorescent proteins. The frequency-doubled all-fiber laser system provides a compact and efficient tool for SHG and fluorescence microscopy.

Bailenger J et al. Ann Parasitol Hum Comp "[Importance of the time of sample taking in order to follow the variations in corticosteronemy during parasitism of the rat by Stronglyoides ratti (author's transl)]."

Bailenger J, Souby J

[Ann Parasitol Hum Comp]

The variations in corticosteronemy induced by the development of Stronglyoides ratti in the Rat can be detected both in the afternoon, when corticosteronemy reaches its maximum, and in the morning when it is at its lowest rate. Nevertheless, hypercorticosteronemy, which is at its maximum 48 hours after infestation, is more sensible in the morning, whereas on the contrary hypocorticosteronemy is more significant in the afternoon and then shows a sudden and very important drop which seems to coincide with the beginning of the expulsion of the adult worms. According to previous results, inhibition of the secretion of gluco-cortico-steroids is caused by the worms; furthermore, Ogilvie and Jones show the determinant role of sensitized lymphocytes, for the expulsion of antibody-damaged worms, whereas some authors suggest that eosinophils act as cytotoxic cells on sensitized helminths; the hypothesis may therefore be put forward that hypocorticosteronemy liberates the intervention of active lymphocytes and eosinophils, triggering so the phenomenon of spontaneous deparasiting.

Zhu Y et al. (2020) Int J Biol Macromol "Water-soluble and alkali-soluble polysaccharides from bitter melon inhibited lipid accumulation in HepG2 cells and Caenorhabditis elegans."

Zhou Y, Dong Y, Zhu Y, Zhao Y, Zhang Y, Bai J, Xiao X

[Int J Biol Macromol, 2020]

Bitter melon polysaccharides (BPS) have been reported to have hypolipidemic effects. However, the precise mechanism of BPS regulating lipid metabolism remains elusive. Water-soluble (WBPS) and alkali-soluble bitter melon polysaccharides (ABPS) were extracted to evaluate the fat-lowering bioactivities in HepG2 cells and Caenorhabditis elegans. WBPS and ABPS were slightly different in the uronic acid contents (22.23% and 5.69%), monosaccharide composition, molecular weight (Mw: 332kDa and 1552kDa, respectively) and IR spectra. In palmitic acid-treated HepG2 cell, the ABPS exhibited better effects on accelerating glucose consumption and decreasing the triglyceride content than WBPS via stimulating glucose consumption (GLUT4) and gluconeogenesis (PEPCK). In the model of glucose-treated C. elegans, we observed that both WBPS and ABPS obviously suppressed the fat accumulation, more significantly by ABPS, along with no toxicity towards some physical activities. Fat-5, fat-6 and fat-7 mediated fatty acid desaturases pathways were further confirmed to be involved in the lipid-lowering effects of BPSs. Our studies demonstrated that both WBPS and ABPS can exhibit effects on fat- lowering in HepG2 cells and C. elegans.

Ma X et al. (2021) Food Funct "Oxidative stress suppression in C. elegans by peptides from dogfish skin via regulation of transcription factors DAF-16 and HSF-1."

Simpson BK, Zhang Y, Ma X, Xia J, Hacariz O, Wang Z, Li J

[Food Funct, 2021]

Functional peptides were obtained <i>via</i> enzymatic hydrolysis of smooth dogfish (<i>Mustelus canis</i>) skin. The enzyme-assisted process was optimized to achieve high yield of smooth dogfish skin peptides (SDSP). Fractions of SDSP (MW &lt; 2 kDa, 2-5 kDa, 5-10 kDa and &gt;10 kDa) showed <i>in vitro</i> antioxidant activities. The peptides &lt;2 kDa (SDSP_{&lt;2 kDa}) significantly improved motility, reduced ROS and H₂O₂ levels of <i>Caenorhabditis elegans</i>, and increased its resistance to oxidative stress compared to the other peptide fractions. <i>In vivo</i> function of SDSP_{&lt;2 kDa} could be explained by their capacity to increase the expression of stress-response genes. The enhanced resistance to oxidative stress mediated by SDSP_{&lt;2 kDa} was dependent on DAF-16 and HSF-1. The amino acid residues and sequences of SDSP_{&lt;2 kDa} were characterized and revealed a higher content of hydrophobic <i>versus</i> polar amino acid contents. This study (especially the <i>in vivo</i> investigation) explored new potent antioxidant peptides derived from dogfish skin.

Aviles-Espinosa R et al. (2011) Biomed Opt Express "Compact ultrafast semiconductor disk laser: targeting GFP based nonlinear applications in living organisms."

Santos SI, Hamilton C, Malcolm G, Aviles-Espinosa R, Weingarten KJ, Sudmeyer T, Keller U, Filippidis G, Barbarin Y, Loza-Alvarez P, Artigas D

[Biomed Opt Express, 2011]

We present a portable ultrafast Semiconductor Disk Laser (SDL) (or vertical extended cavity surface emitting laser-VECSELs), to be used for nonlinear microscopy. The SDL is modelocked using a quantum-dot semiconductor saturable absorber mirror (SESAM), delivering an average output power of 287 mW, with 1.5 ps pulses at 500 MHz and a central wavelength of 965 nm. Specifically, despite the fact of having long pulses and high repetition rates, we demonstrate the potential of this laser for Two-Photon Excited Fluorescence (TPEF) imaging of in vivo Caenorhabditis elegans (C. elegans) expressing Green Fluorescent Protein (GFP) in a set of neuronal processes and cell bodies. Efficient TPEF imaging is achieved due to the fact that this wavelength matches the peak of the two-photon action cross section of this widely used fluorescent marker. The SDL extended versatility is shown by presenting Second Harmonic Generation images of pharynx, uterus, body wall muscles and its potential to be used to excite other different commercial dyes. Importantly this non-expensive, turn-key, compact laser system could be used as a platform to develop portable nonlinear bio-imaging devices.