Geng W et al. (2003) Genetics "Quantitative classification and natural clustering of Caenorhabditis elegans behavioral phenotypes."

Geng W, Baek JH, Berry CC, Schafer WR, Cosman P

[Genetics, 2003]

Genetic analysis of nervous system function relies on the rigorous description of behavioral phenotypes. However, standard methods for classifying the behavioral patterns of mutant Caenorhabditis elegans rely on human observation and are therefore subjective and imprecise. Here we describe the application of machine learning to quantitatively define and classify the behavioral patterns of C. elegans nervous system mutants. We have used an automated tracking and image processing system to obtain measurements of a wide range of morphological and behavioral features from recordings of representative mutant types. Using principal component analysis, we represented the behavioral patterns of eight mutant types as data clouds distributed in multidimensional feature space. Cluster analysis using the k-means algorithm made it possible to quantitatively assess the relative similarities between different behavioral phenotypes and to identify natural phenotypic clusters among the data. Since the patterns of phenotypic similarity identified in this study closely paralleled the functional similarities of the mutant gene products, the complex phenotypic signatures obtained from these image data appeared to represent an effective diagnostic of the mutants' underlying molecular defects.

Geng W et al. (2004) IEEE Trans Biomed Eng "Automatic tracking, feature extraction and classification of C elegans phenotypes."

Berry CC, Schafer WR, Geng W, Feng Z, Cosman P

[IEEE Trans Biomed Eng, 2004]

This paper presents a method for automatic tracking of the head, tail, and entire body movement of the nematode Caenorhabditis elegans (C. elegans) using computer vision and digital image analysis techniques. The characteristics of the worm''s movement, posture and texture information were extracted from a 5-min image sequence. A Random Forests classifier was then used to identify the worm type, and the features that best describe the data. A total of 1597 individual worm video sequences, representing wild type and 15 different mutant types, were analyzed. The average correct classification ratio, measured by out-of-bag (OOB) error rate, was 90.9%. The features that have most discrimination ability were also studied. The algorithm developed will be an essential part of a completely automated C. elegans tracking and identification system.

Ashrafi K (2022) Cell Host Microbe "Better living through communal eating."

Ashrafi K

[Cell Host Microbe, 2022]

Caenorhabditis elegans do not grow on either Staphylococcus saprophyticus or heat-killed Escherichia coli, but do so when exposed to both. In this issue of Cell Host & Microbe, Geng and colleagues have identified E.coli-derived signals as well as the host's neural and innate immunity pathways that promote digestion of S.saprophyticus.

Nawa Y et al. (1985) Parasite Immunol "Defective protective capacity of W/Wv mice against Strongyloides ratti infection and its reconstitution with bone marrow cells."

Kotani M, Nawa Y, Kiyota M, Korenaga M

[Parasite Immunol, 1985]

The susceptibility of congenitally anemic, and mast cell deficient W/Wv mice to infection with Strongyloides ratti was examined. After a primary infection, W/Wv mice showed greater and more persistent peak larval counts than did normal littermates. Worm expulsion was also slower in W/Wv mice than in +/+ mice. Furthermore, difference in susceptibility was expressed as early as 24 h after infection, suggesting not only that protective mechanisms of the gut but also of the connective tissue were defective in W/Wv mice. Reconstitution with bone marrow or spleen cells from +/+ mice was effective in restoring the protective response in W/Wv mice, whereas thymocytes or mesenteric lymph nodes had no effect. Both connective tissue and mucosal mast cells were repaired in W/Wv mice after marrow reconstitution and infection. Since relatively long incubation period was required for the expression of such reconstituting activities, bone marrow cells seem to contain precursor cells of the effector and/or regulator cells.

Casiraghi M et al. (2004) Int J Parasitol "Mapping the presence of Wolbachia pipientis on the phylogeny of filarial nematodes: evidence for symbiont loss during evolution."

Guerrero R, Bandi C, Franceschi A, Pocacqua V, Gardner SL, Casiraghi M, Martin C, Bain O

[Int J Parasitol, 2004]

Wolbachia pipientis is a bacterial endosymbiont associated with arthropods and filarial nematodes. In filarial nematodes, W. pipientis has been shown to play an important role in the biology of the host and in the immuno-pathology of filariasis. Several species of filariae, including the most important parasites of humans and animals (e.g. Onchocerca volvulus, Wuchereria bancrofti and Dirofilaria immitis) have been shown to harbour these bacteria. Other filarial species, including an important rodent species (Acanthocheilonema viteae), which has been used as a model for the study of filariasis, do not appear to harbour these symbionts. There are still several open questions about the distribution of W. pipientis in filarial nematodes. Firstly the number of species examined is still limited. Secondly, it is not clear whether the absence of W. pipientis in negative species could represent an ancestral characteristic or the result of a secondary loss. Thirdly, several aspects of the phylogeny of filarial nematodes are still unclear and it is thus difficult to overlay the presence/absence of W. pipientis on a tree representing filarial evolution. Here we present the results of a PCR screening for W. pipientis in 16 species of filariae and related nematodes, representing different families/subfamilies. Evidence for the presence of W. pipientis is reported for five species examined for the first time (representing the genera Litomosoides, Litomosa and Dipetalonema); original results on the absence of this bacterium are reported for nine species; for the remaining two species, we have confirmed the absence of W. pipientis recently reported by other authors. In the positive species, the infecting W. pipientis bacteria have been identified through 16S rDNA gene sequence analysis. In addition to the screening for W. pipientis in 16 species, we have generated phylogenetic reconstructions based on mitochondrial gene sequences (12S rDNA; COI), including a total of 28 filarial species and related spirurid nematodes. The mapping of the presence/absence of W. pipientis on the trees generated indicates that these bacteria have possibly been lost during evolution along some lineages of filarial nematodes.

Li Z et al. (2018) Pak J Pharm Sci "Cellulase-assisted extraction and anti-ultraviolet activity of polysaccharides from the root of Flammulina velutipes on Caenorhabditis elegans."

Chen M, Lin L, Zhang Y, Wang T, Cui H, Wang C, Li Z

[Pak J Pharm Sci, 2018]

We investigated the cellulase-assisted extraction and anti-ultraviolet activity of water-soluble polysaccharides from the root of Flammulina velutipes on Caenorhabditis elegans. A Box-Behnken design experiment with three factors and three levels, including enzymolysis temperature, microwave time, and microwave power, was designed on the basis of the results of single-factor experiments. For improving the polysaccharide yield of F. velutipes root, the following optimal extraction conditions were used: 52.67C enzymolysis temperature, 80s microwave time, and 144 W microwave power. Under optimal conditions, the actual measured value of the yield was 2.01% (w/w) and the predicted value was 2.06% (w/w). One fraction (FRP-2) was isolated and purified, and its characteristics were analyzed. The average mean molecular weight of FRP-2 was measured to be 2.60x10⁵ Da, and its monosaccharide composition is mainly glucose. The sugar units are present both in the -configuration and -configuration. Moreover, FRP-2 exhibited certain anti-ultraviolet activity to C. elegans when the polysaccharide concentration ranged between 0.05mg/mL and 0.20mg/mL.

Manzanares P et al. (2018) Int J Mol Sci "Tryptophan-Containing Dual Neuroprotective Peptides: Prolyl Endopeptidase Inhibition and Caenorhabditis elegans Protection from -Amyloid Peptide Toxicity."

Ramon D, Martinez R, Martorell P, Manzanares P, Garrigues S, Genoves S, Marcos JF

[Int J Mol Sci, 2018]

Neuroprotective peptides represent an attractive pharmacological strategy for the prevention or treatment of age-related diseases, for which there are currently few effective therapies. Lactoferrin (LF)-derived peptides (PKHs) and a set of six rationally-designed tryptophan (W)-containing heptapeptides (PACEIs) were characterized as prolyl endopeptidase (PEP) inhibitors, and their effect on -amyloid peptide (A) toxicity in a <i>Caenorhabditis elegans</i> model of Alzheimer's disease (AD) was evaluated. Two LF-derived sequences, PKH8 and PKH11, sharing a W at the C-terminal end, and the six PACEI heptapeptides (PACEI48L to PACEI53L) exhibited significant in vitro PEP inhibition. The inhibitory peptides PKH11 and PACEI50L also alleviated A-induced paralysis in the in vivo <i>C. elegans</i> model of AD. Partial or total loss of the inhibitory effect on PEP was achieved by the substitution of W residues in PKH11 and PACEI50L and correlated with the loss of protection against A toxicity, pointing out the relevance of W on the neuroprotective activity. Further experiments suggest that <i>C. elegans</i> protection might not be mediated by an antioxidant mechanism but rather by inhibition of A oligomerization and thus, amyloid deposition. In conclusion, novel natural and rationally-designed W-containing peptides are suitable starting leads to design effective neuroprotective agents.

Engelbrecht F et al. (2003) Parasitol Int "Analysis of Wuchereria bancrofti infections in a village community in northern Nigeria: increased prevalence in individuals infected with Onchocerca volvulus."

Enwezor F, Engelbrecht F, Kaliraj P, Philipp D, Oettl T, Link C, Edeghere H, Herter U

[Parasitol Int, 2003]

Infections with Wuchereria bancrofti causing lymphatic filariasis still represent one of the major health problems in the tropics, with 120 million people infected and over 750 million exposed to this filarial parasite. We have studied lymphatic filariasis infections as part of a multi-parasite survey in a village community in the savannah of northern Nigeria. We analysed serum samples from 341 individuals aged 5-70 years, detecting a W. bancrofti circulating antigen using the commercially available ICT Filariasis card test. The prevalence of infections was 10% and clearly age-dependent, increasing from below 2% in children to over 20% in subjects older than 40 years. Measuring IgG4 antibodies against the recombinant W. bancrofti antigen SXP1 showed that 36% of all tested individuals had been at least exposed to the parasite. Antibody levels also increased very significantly with age. A further analysis measuring Onchocerca volvulus-specific IgG4 antibodies showed a very significant association between infections with O. volvulus and those with W. bancrofti. Our data show that infections with W. bancrofti in Nigeria are still a frequently occurring health problem, since they are more prevalent than previously reported, and that individuals with an O. volvulus infection are more often infected with W. bancrofti than expected statistically.

Abe T et al. (1987) Parasite Immunol "Localization of mucosal mast cells in W/Wv mice after reconstitution with bone marrow cells or cultured mast cells, and its relation to the protective capacity to Strongyloides ratti infection."

Nawa Y, Abe T

[Parasite Immunol, 1987]

Localization of mast cells in the intestinal epithelium, villous lamina propria and basal lamina propria of mast cell-deficient WBB6F1 (W/Wv) mice reconstituted with either bone marrow cells or with cultured mast cells (BMMC) was compared to that of mast cell-sufficient C57BL/6 or C57BL/6-bgj/bgj (beige) mice after infection with Strongyloides ratti. In mast cell-sufficient C57BL/6 or beige mice, the maximum number of intestinal mucosal mast cells (MMC) was more than 160 MMC/10 villus crypt units (VCU) and more than 90% of MMC were located in the intestinal epithelium. When W/Wv mice were reconstituted with bone marrow cells of beige mice, worm expulsion was hastened and the MMC response became comparable to that of mast cell-sufficient mice in terms of cell numbers and their intra-epithelial localization. On the other hand, when W/Wv mice were reconstituted with BMMC of beige mice, only a few donor type MMC were detected in the intestine. The proportion of intra-epithelial MMC was lower than that of mast cell-sufficient mice or of marrow-reconstituted W/Wv mice. Even repeated injection of BMMC could not fully restore the number of intra-epithelial MMC to the level of that observed in mast cell-sufficient mice. Since mast cell-growth factor-producing activity of W/Wv mice was comparable to that of mast cell-sufficient mice, the ineffectiveness of BMMC-transfer in restoring protective activity or MMC responses in W/Wv mice seems to be attributed to the functional immaturity or inactivity of BMMC.

Martin C et al. (2021) Chemosphere "Bioassays to assess the ecotoxicological impact of polyethylene microplastics and two organic pollutants, simazine and ibuprofen."

Mengs G, Nande M, San Andres MD, Fajardo C, Martin C, Sanchez-Fortun S, Gonzalez F, Martin M, Costa G

[Chemosphere, 2021]

Research on the environmental impact of plastics, especially on the effect of microplastics (MPs), has become a priority issue in recent years, mainly in terrestrial ecosystems where there is a lack of studies. This work aims to assess the impact of two types of polyethylene MPs, white microbeads (W) and fluorescent blue microbeads (FB), and their interactions with two contaminants, ibuprofen (Ib) and simazine (Sz), on different organisms. A set of bioassays for Vibrio fischeri, Caenorhabditis elegans and Lactuca sativa was carried out, which helped to establish the ecotoxicological impact of those pollutants. C.elegans showed the least sensitivity, while V.fischeri and L.sativa showed a high toxicological response to MPs alone. We found that W and FB induced an inhibition of 27% and 5.79%, respectively, in V.fischeri, and the growth inhibition rates were near 70% in L.sativa for both MPs. MPs exhibited a potential role as contaminant vectors in V.fischeri since the inhibition caused by W-Ib or W-Sz complexes was near 39%. The W-Sz complex significantly reduced leaf development in L.sativa, and a reduction of 30% in seed germination was detected when the complex FB-Sz was tested. This study reveals the importance of designing a complete set of analyses with organisms from different trophic levels, considering the great variability in the effects of MPs and the high number of relevant factors.