Search

Fetal bovine serum (FBS) plays a pivotal role in animal cell culture. Due to ethical and scientific issues, searching for an alternative, comprising the three R's (Refinement, Reduction and Replacement) gained global attention. In this context, we have identified the heat inactivated coelomic fluid (HI-CF) of the earthworm, Perionyx excavatus as a potential alternative for FBS. Briefly, we formulated HI-CF (f-HICF) containing serum free medium which can aid the growth, attachment, and proliferation of adherent cells, similar to FBS. In this study, we investigated the biochemical characterization, sterility, stability, formulation, and functional analysis of HI-CF as a supplement in culturing animal cells. Notably, vitamins, micronutrients, proteins, lipids, and trace elements are identified and compared with FBS for effective normalization of the serum free media. HI-CF is tested to be devoid of endotoxin and mycoplasma contamination thus can qualify the cell culture grade. The f-HICF serum free media was prepared, optimised, and tested with A549, HeLa, 3T3, Vero and C2C12 cell lines. Our results conclude that f-HICF is a potential alternative to FBS, in accordance with ethical concern; compliance with 3R's; lack of unintended antibody interactions; presence of macro and micronutrients; simple extraction; cost-effectiveness and availability. [ABSTRACT FROM AUTHOR]

Acetamiprid is a broad-spectrum insecticide, belonging to the neonicotinoid compounds group, which has been extensively applied throughout the globe. Recently, indiscriminate use of these compounds was reported to cause fatal impacts on non-targeted soil organisms. Hence, the present study aimed to examine the impact of acetamiprid on Indian indigenous earthworm, Perionyx excavatus. Acute toxicity revealed an LC50 concentration of 0.25 µg/cm2 for filter paper test/72 h and 400 µg/kg for artificial soil test/14 days. Oxidative stress (ROS) and various biomarkers including superoxide dismutase, catalase, glutathione S-transferase, malondialdehyde content and DNA damage were measured. The results of the biomarker responses confirmed the acetamiprid exposure can cause toxicity to P. excavatus. In addition, cell density (20 × 102 cell mL/mg) and cell viability (40%) were significantly (p < 0.05) reduced. Further, the ecotoxicological assessment made through this study can be utilized as good evidence to toxicity of neonicotinoids to non-targeted indigenous organisms. [ABSTRACT FROM AUTHOR]

The ideal condition of earthworm gut promotes growth and multiplication of beneficial soil microorganisms eliminating pathogens and converts organic wastes into nutrients rich compost. The present study has been carried out to determine the population dynamics of earthworm gut bacteria and to find out relative abundance of different functional bacterial groups in the foregut, midgut, and hindgut of earthworm Perionyx excavatus. To assess bacterial diversity, a viable plate count method was adopted. In the different gut region of earthworm, aerobic heterotrophic, amylolytic, Bacillus, Gram-negative, proteolytic, fat hydrolyzing, nitrate-reducing, nitrifying, asymbiotic nitrogen-fixing, Azotobacter, and phosphate solubilizing bacterial populations ranged from 22.2 to 241.6 × 106, 8.0 to 171.60 × 106, 1.83 to 2.79 × 106, 10.68 to 23.04 × 104, 3.70 to 5.52 × 104, 59.60 to 208.40 × 104, 1.86 to 7.34 × 104, 10.94 to 19.78 × 104, 0.80 to 3.42 × 104, 7.83 to 13.70 × 104, 1.31 to 2.67 × 104 cfu/ml gut suspension, respectively. The results of the one-way ANOVA revealed that the bacterial load of most of the bacterial groups was significantly higher (p < 0.05) in the hindgut region, followed by midgut and foregut. Only the density of the proteolytic group was significantly higher (p < 0.05) in the midgut region followed by foregut and hindgut. Starch hydrolyzing bacteria constitute the largest group of bacteria in the gut content. From principal component analysis, two components were extracted with the eigenvalues of 8.485 and 1.132. Agglomerative hierarchical cluster analysis revealed that the bacterial populations were clustered into four different groups. Quantitative variation among bacterial groups in earthworm's gut seems to determine the soil health and composting efficiency; from this point of view, the present study will provide a better understanding about different functional bacterial groups of earthworm's guts and might be helpful in sustainable agriculture and waste management. [ABSTRACT FROM AUTHOR]

Alternative plant growing inputs have been increasingly sought out to reduce the economic-environmental impacts of intensive use of synthetic fertilizers in conventional agriculture. This study aimed to evaluate the production components of lettuce in response to the use of earthworm compost in substrate compositions. The experiment was carried out in a greenhouse using a completely randomized design in a 3 x 5 factorial scheme, with six replications, testing three earthworm species (Eisenia andrei, Eudrilus eugeniae, and Perionyx excavatus) and five drilocompost ratios (0%, 25%, 50%, 75%, and 100%), produced by these species and added to the composition of substrates by mixing them with soil. Production components evaluated comprised total and commercial numbers of leaves, commercial fresh weight, as well as shoot and total fresh and dry weights. Lettuce production components increased as the drilocompost ratio in substrates was raised, regardless of the earthworm species. Moreover, the addition of 25% this drilocomposted material in the dystrophic soil was enough to improve its fertility condition. In general, substrates prepared with worm castings from Perionyx excavatus and Eudrilus eugeniae were more efficient in increasing lettuce production components than that from Eisenia andrei. [ABSTRACT FROM AUTHOR]

The data on growth and reproduction of composting earthworms may be beneficial for large scale earthworm production. The growth and reproduction of Perionyx excavatus were assessed in limited supplies of four experimental diets-cow dung alone and its mixture with acacia (Acacia auriculiformis) leaf litter, bamboo (Bambusa polymorpha) leaf litter and terrestrial weed Mikania micrantha under laboratory conditions to select suitable diet from our locally available resource for vermiculture. Growth performance of Perionyx excavatus was significantly (P<0.05) higher in cow dung (maximum weight mg worm-1 629 and growth rate mg worm-1 day-1 22.91). The rate of reproduction (0.3 cocoons worm-1 day-1 and 3.31 juveniles adult-1 week-1) was significantly higher (P<0.05) in acacia-cow dung mixture. The cocoon production was maximum on the 30th day in all experimental diets (cow dung, acacia-cow dung, bamboo-cow dung, mikania-cow dung). All the diets showed a maximum peak of juvenile production on the 45th day. The lowest rate of biomass increase as well as the rate of reproduction were observed in mikania-cow dung mixture. Present result indicates that cow dung and acacia leaf litter can be used as vermiculture substrate for P. excavatus. [ABSTRACT FROM AUTHOR]

Objective: The purpose of the experiment was to examine the effect of different food sources on the growth and reproduction performances of an epigeic earthworm Perionyx excavatus. Materials and Methods: The experiment was carried out in 18 cylindrical plastic containers for 10 weeks. The study was designed with six treatments, each having three replicates. In control treatment (T1), cow dung was used as the only food source for the earthworm. In another five treatments, water hyacinth (T2), chopped banana plant trunk (T3), vegetable scrap (T4), paddy straw (T5), and sugarcane bagasse (T6) were used as food sources with cow dung as bedding material. Results: The maximum weight gain of earthworm P. excavatus was 3,294.7 ± 4.5 mg for the food staff of vegetable scrap (T4). Earthworm P. excavatus fed with chopped banana plant trunk (T3) showed a very similar weight gain of 3,243.7 ± 3.8 mg. On the contrary, the minimum weight gain was 1,799.7 ± 3.5 mg for the food staff of paddy straw (T5). The maximum cocoon number of 137.33 ± 6.46 mg was observed in T3, whereas a minimum number of 36.67 ± 4.16 mg in T1. The highest number of hatchlings (12.33 ± 0.88 mg) was recorded in treatment T3, whereas the least number of hatchling (5.00 ± 0.58 mg) was observed in T1. Conclusion: It was concluded that, among the six different food sources, chopped banana plant trunk was preferable food source to the earthworm for growth and reproduction. [ABSTRACT FROM AUTHOR]

Biological and behavioral responses of the tropical earthworm Perionyx excavatus towards different concentrations of abamectin were evaluated. Abamectin significantly reduced the biomass and reproduction (cocoon production) of P. excavatus as well as inducing histopathological alterations in the cuticle. Biomass loss was recorded in P. excavatus exposed to abamectin at a concentration as low as 0.1 mg active ingredient (a.i.) kg−1, while atrophy, another physiological response, was observed at an abamectin concentration of 0.21 μg cm−2 in a filter paper test. Cocoon production was significantly reduced in the presence of abamectin, and no cocoons were produced at doses of 20 mg a.i. kg−1 or higher, while abamectin at 50 mg a.i. kg−1 induced extreme pathology, characterized by the loss of the integrity of the whole body wall and intestine of P. excavatus. Histopathological alterations can be used as a biomarker to evaluate the toxicological impact of exposure to abamectin. [ABSTRACT FROM AUTHOR]

The lignocellulosic wastes, cashew leaf litter (CLL) admixed with various animal dungscowdung (CD), sheepdung (SD) and horsedung (HD) have been subjected to vermicomposting by using indigenous earthworms, Perionyx excavatus and Lampito mauritii and to produce value added vermicompost. Four different combinations of each [100% dung alone, 3 : 1 (75% dung + 25% CLL), 2 : 2 (50% dung + 50% CLL) and 1 : 3 (25% dung + 75% CLL)] vermibeds were prepared for vermicomposting process. After 60 days, the vermicompost and worm-unworked normal compost were harvested and characterized and growth (biomass), reproductive performance of earthworms-cocoon production, hatchling number and recovery of vermicompost were also studied. The obtained results clearly showed that vermicompost from CLL admixed with CD at 2 : 2 ratio had lower pH, organic carbon, C–N ratio, C–P ratio, lignin, cellulose, hemicellulose and phenol content, and higher nitrogen, phosphorus, potassium, dehydrogenase and humic acid content than the raw substrates and normal compost. Also pronounced and better earthworm activity was found in the above combination for both species. Hence organic farming practices using vermicompost promise an alternative to the existing practices and proved as a sustainable approach. [ABSTRACT FROM AUTHOR]

The earthworm Perionyx excavatus is a species highly capable of bidirectional regeneration. Pair-rule genes are thought to have an ancestral function in arthropod segmentation. However, orthologs in annelids (i.e. Capitella teleta) do not exhibit segmental expression in the ectoderm or mesoderm. Their role in regeneration is currently unclear. Here, we report the expression profile of primary pair-rule genes (Pex-EvxA, Pex-EvxB, Pex-RuntA, Pex-RuntB, Pex-Hes1A, Pex-Hes1B, Pex-Hes4A, and Pex-Hey) found in P. excavatus using semi-quantitative reverse transcription-polymerase chain reaction. Our results indicated these genes showed variable expression during bidirectional regeneration. Six of these genes might play diverse and potentially critical roles in head and/or tail regeneration. [ABSTRACT FROM AUTHOR]

Eisenia foetida and Perionyx excavatus are potent vermicomposting earthworms having immense importance in organic matter recycling under tropical conditions, particularly in India. Comparative assessment of the cultivable gut microbiome of these two epigeic earthworms after growth on lignocellulosic biomass, revealed populations of 3.2-8.3 × 109 CFU. Diversity analyses using 16S rDNA sequences revealed that the major dominating classes were Firmicutes (50-60%), followed by Actinobacteria (26.7-33%), and Alphaproteobacteria (5.6-6.7%). Despite exhibiting similar diversity indices and species richness, Betaproteobacteria (6.7%) and Gammaproteobacteria (11.1%) were solely present in E. foetida and P. excavatus, respectively. A set of 33 distinct morphotypes, including 18 from E. foetida and 15 from P. excavatus were selected. Carbohydrate utilization profiles generated using Hi-Carbo™ kits revealed that the isolates from the gut of P. excavatus - Arthrobacter pascens IARI-L13 and Bacillus subtilis IARIC were able to utilize 54 and 51.4% of the carbohydrates tested. Sorbose was not utilized, while unusual carbohydrates - adonitol and methyl- d-mannoside were utilized only by members from the gut of P. excavatus, while melizitose was utilized by those uniquely by E. foetida microbiome. Functional characterization revealed that β-glucosidase activity was most prevalent in the culturable microbial community. Alkaline and acid phosphatase activity was more widespread in the E. foetida gut microbiome. All the culturable gut bacterial isolates produced ammonia, but IAA was detected only in five cultures. The unique functional attributes of the two culturable microbiomes, grown on a similar diet, reveals the significance of proper selection of earthworm substrate combinations for effective vermicomposting. [ABSTRACT FROM AUTHOR]

Agriculture is an important part of the economy of the undivided Midnapore district. Agricultural land is its asset and most importantly its means of sustenance as well as survival. Earthworms are invertebrates that play a key role in recycling organic matters in soils. Since the intestines of earthworms harbor wide ranges of microorganisms, enzymes, hormones etc., these half digested materials decompose rapidly and are transformed into a stabilized material called vermicompost which is very useful for increasing the soil fertility. One has to look for these characters before recommending any species for vermiculture. In the present study, Perionyx excavatus specimens were collected from the undivided Midnapore district and from the Earthworms gut, bacteria, fungus, actinobacteria, and yeast were isolated and identified using various morphological and biochemical tests. All the bacterial isolates were identified using morphological study, staining techniques, and different biochemical tests such as catalase test, KOH test, H2SO4 test, Starch hydrolysis test, oxidase test, and sucrose hydrolysis test. All the fungal, actinobacteria, and yeast isolates were subjected to staining and morphological characterization (color and texture of fungal colony). Bacterial isolates of genus Bacillus sp., Staphylococcus sp., Enterococci, Micrococcus sp., Enterobacter sp., and Citrobacter sp. were identified. Among the fungal isolates Aspergilus sp., and P. boydii were identified. Streptomyces sp., Nocardia sp. among the actinobacteria and Candida sp. among yeast were also found to be present in earthworm gut and these might play an important role along with the earthworm to increase the quality and fertility of soil. [ABSTRACT FROM AUTHOR]

The recently developed concept of high rate vermicomposting was successfully used to enable direct vermicomoposting of neem leaves-without any pre-composting or cow dung supplementation as previously reported processes had necessitated. All the three epigeic species of earthworms that were explored, Eudrilus eugeniae, Eisenia fetida and Perionyx excavatus, provided efficient vermicast production with no mortality, persistent gain in body mass and good fecundity over the 16 months long period of reactor operation. In this period, all reactors were pulse-fed at the solid retention time of 20 days and were operated in the pseudo discretized continuous operation protocol developed earlier by the authors. With this, it was possible to almost completely dampen the influence of natural biodegradation of the feed or grazing by the earthworm born in the vermireactors. The findings, thus, conclusively prove that, all-through, the brisk vermicomposting was caused almost entirely by the action of the 'parent' earthworms on fresh feed. [ABSTRACT FROM AUTHOR]

The aim of the study was to examine safe reuse and recycling of organic waste digestate obtained from a biogas plant (5 % total solid) with enhanced nutrient value through vermitechnology. Two indigenous epigeic earthworm species Perionyx excavates and Perionyx sansibaricus were tried individually for this purpose. The results clearly show a significant increase in pH values from 6.5-7.4, electrical conductivity (21.3-21.7 %), total N (84.5-94.6 %), total P (35.9-47.1 %), total K (49.8-52.6 %), Ca (41.9-41.9 %) and a significant decrease in total organic C (17.1-22.4 %), C/N ratio (7.2-6.9), C/P ratio (20.3-20.6), COD (51.9-55.7 %), BOD (85.5-91.2 %). Similarly, indicator organisms (fecal coliforms and fecal streptococci) showed decrement at the end of the composting period (60 days). Fecal Coliforms reduce to nil, while in fecal streptococci a 6 log reduction was observed. Oxygen uptake rate dropped to 67.4-70 % for vermireactors. Overall, the aforementioned findings highlighted that the indigenous earthworm species could enhance the nutrient value of the anaerobic digestate, which could be utilized as an efficient soil conditioner. [ABSTRACT FROM AUTHOR]

Introduction: This work illustrates the productivity of composting earthworm Perionyx excavatus under different stocking density (in milligrams biomass per cubic centimeter vermibed space) gradients in cattle dung decomposing system. Materials and methods: Earthworm biomass and reproduction performance was tested in vermibeds with five different stocking density loads: 0.0680 mg cm (T), 0.1388 mg cm (T), 0.205 mg cm (T), 0.274 mg cm (T), and 0.342 mg cm (T). Results and conclusion: Results thus suggested the direct relationship between earthworm performance and stocking density load in vermicomposting system. P. excavatus showed the maximum individual biomass production in low-stocking density trials, while cocoon production rate was better in vermibeds with high-density trials. The statistical interrelationships between stocking density load and individual growth parameters of inoculated earthworms were also tested. The statistical interpretation also suggested the impact of stocking density load on earthworm growth and reproduction parameters in vermicomposting system, although further detailed studies are required to measure the earthworm growth behavior under the maximum carrying capacity load of a vermibed. [ABSTRACT FROM AUTHOR]

In India the exotic epigeic species, Eisenia fetida is mostly used for vermicomposting. The introduction of exotic species into local bio system may affect the indigenous earthworm species population. A comparative study between exotic species (Eisenia fetida) and indigenous species Perionyx sansibaricus and Perionyx excavates was performed to determine the potential of indigenous species of the area vis-à-vis the exotic species for composting of domestic organic waste blended with cattle manure. The results of the study show a significant reduction in initial C/N ratio from 55 to 13 for P. excavates and 15 for P. sansibaricus of the ready product which was within the agronomic acceptable limit ( < 20). The total organic matter reduced by 50% and pH also reduced to be nearer to neutral, but there was an increase in total nitrogen to 102% and total phosphorus increased from the initial concentration of 7.62 g kg−1 up to 13.2 g kg−1. Overall, by employing above indigenous species, domestic organic waste can be directly converted into high-quality hygienic stable fertilizer (vermicompost) which is rich in nitrogen, phosphorus and potassium and free from pathogens. [ABSTRACT FROM PUBLISHER]

Effects of sub-lethal doses of carbaryl (1-Naphthyl-methylcarbamate), chlorpyrifos (O,O-diethyl O-3,5,6-trichloro-2-pyridinyl-phosphorothioate) and endosulfan (6,7,8,9,10,10-Hexachloro-1,5,5a,6,9,9a-hexahydro-6,9-methano-2,4,3-benzodioxathiepin-3-oxide), respectively a carbamate, an organophosphate and an organochlorine insecticide on growth, reproduction and respiration of the tropical earthworm, Perionyx excavatus (Perrier) were investigated under laboratory conditions. The results showed significant reduction in biomass, production and hatching of cocoon and production of juveniles of the worms exposed to 0.75 to 3.03 mg/kg soil of carbaryl, 0.91 to 3.65 mg/kg soil of chlorpyrifos and 3.75 to 15.0 μg/kg soil of endosulfan corresponding to 12.5 to 50 % of LC50 value of the respective insecticide for P. excavatus. Endosulfan was found most dangerous among the three insecticides followed by carbaryl and chlorpyrifos. There was no hatching of the worms at endosulfan treatment 5.0 μg/kg soil (25 % LC50) or above while the highest dose of carbaryl and chlorpyrifos (50 % of LC50) rendered respectively 87.13 and 24.84 % reductions in hatching as compared to control. Chlorpyrifos produced no change in respiration of the worms except at the highest dose, while the worms showed an increase in evolution of CO2 at all doses of carbaryl and endosulfan. Based on the recommended agricultural dose of each insecticide, it was concluded that application of endosulfan and carbaryl was potentially dangerous to earthworms. [ABSTRACT FROM PUBLISHER]

The 96 h LC50 values of six insecticides were determined on a non-target epigeic earthworm Perionyx excavatus under laboratory conditions. Cypermethrin was found most toxic to P. excavatus (LC50-0.008 mg/kg), followed by endosulfan (LC50-0.03 mg/kg), carbaryl (LC50-6.07 mg/kg), chlorpyrifos (LC50-7.3 mg/kg), aldicarb (LC50-10.63 mg/kg) and monocrotophos (LC50-13.04 mg/kg). When these LC50 values were compared with their respective recommended agricultural doses, aldicarb and carbaryl appeared more dangerous than other pesticides because of their lower LC50 values than their respective recommended agricultural dose. Mean lethal time to cause 50% mortality at recommended agricultural dose (LT50) also indicated that aldicarb achieved the fastest LT50 (26 h) followed by endosulfan (38 h) and carbaryl (44 h) indicating the danger of these pesticides to P. excavatus. [ABSTRACT FROM AUTHOR]

The article presents a study which shows a full length cloning of the complementary DNA (cDNA) of Perionyx excavatus, an earthworm which is known to have a high regenerative ability, and the regeneration of its three labial genes. The study employs reverse transcription-polymeras chain reaction to analyze the expression pattern during the regeneration of the head, trunk and tail fragments. Results of the study show that three labial genes are apparent only with the head-regenerating tissues.

Epigeic earthworms (Oligochaeta) have been appeared as key organisms to convert organic waste resources into value-added products, i.e., vermicompost and worm biomass. The assessment of reproduction potential of composting earthworm may be beneficial for large-scale earthworm production. Although, the waste minimizing potential of Perionyx excavatus and Perionyx sansibaricus is well proved, but little information is available about their fecundity rate. In this study, the efforts have been made to explore the growth and reproduction biology of P. excavatus and P. sansibaricus, using cattle waste solid as culture substrate, under laboratory conditions. Earthworms were weighed weekly and number of cocoons produced per week assessed. Biomass productions, fecundity, maturation, natality all were significantly different between P. excavatus and P. sansibaricus. The highest mean individual biomass was 767.7 ± 18.4 mg and 612.6 ± 20.6 mg, respectively in P. sansibaricus and P. excavatus. However, the highest cocoon numbers occurred in P. excavatus (492.3 ± 13.6), significantly higher than P. sansibaricus (269.6 ± 17.1). Fecundity was slightly different in both species: 1.38 ± 0.77 cocoons adult worm−1 week−1 ( P. excavatus) and 1.58 ± 0.74 cocoons adult worm−1 week−1 ( P. sansibaricus). The hatchling success rate (%) was highest in P. excavatus. Overall natality (juveniles adult−1 week−1) was highest in P. sansibaricus (1.52) than P. excavatus (1.26), which suggests that P. sansibaricus may be a better candidate for rapid propagation of earthworms in cattle waste solid. [ABSTRACT FROM AUTHOR]

The Hox genes of the oligochaete, Perionyx excavatus, were surveyed using PCR and phylogenetic analysis. We were able to identify 11 different Hox gene fragments. Comparative and phylogenetic analyses revealed that this oligochaete would have at least five Hox genes of the anterior group, including three copies of labial-type, five of the central group and one of the posterior group. This is the first report regarding sequence information and phylogenetic analysis of Hox genes in the earthworm. [ABSTRACT FROM AUTHOR]

An outdoor study was undertaken using polyethylene containers to assess the suitability of different organic residues, soybean straw ( Glycine max L. Merril.), wheat straw ( Triticum aestivum L.), maize stover ( Zea mays L.), chickpea straw ( citer arietinum L.) and city garbage, as food for the tropical epigeic earthworm Perionyx excavatus, and to assess the influence of this earthworm on the decomposition of these materials. Maize stover was found to be the most suitable of the food materials used. Population growth of P. excavatus was enhanced by addition of these organic materials in the temperature range 24°-30°C, while the population was adversely affected above 30°C in a vermiculture system. Addition of earthworms accelerated the breakdown of residues, which ultimately resulted in a lowering of the C:N ratio, water-soluble carbon and carbohydrates, and increased ash percentage and cation exchange capacity compared with their respective controls. [ABSTRACT FROM AUTHOR]

The biology of the oriental vermicomposting species, Perionyx excavatus, is poorly understood. Quantitative observations were made at 25°C in urine free cattle manure in order to study the growth of this species. The rate of maturation and cocoon production were studied under conditions of favourable moisture and nutrition over a period of 250 days. The results obtained showed that while P. excavatus grows relatively slowly compared to other vermicomposting species, it attains sexual maturity much earlier and maintains a relatively high cocoon production rate. The study revealed that copulation is not a prerequisite for production of viable cocoons, indicating that P. excavatus may be parthenogenetic and possibly capable of alternating between modes of reproduction. [ABSTRACT FROM AUTHOR]

Regeneration is a biological process restoring lost or amputated body parts. The capability of regeneration varies among organisms and the regeneration of the central nervous system (CNS) is limited to specific animals, including the earthworm Perionyx excavatus. Thus, it is crucial to establish P. excavatus as a model system to investigate mechanisms of CNS regeneration. Here, we set up a culture system to sustain the life cycle of P. excavatus and characterize the development of P. excavatus, from embryo to juvenile, based on its morphology, myogenesis and neurogenesis. During development, embryos have EdU-positive proliferating cells throughout the whole body, whereas juveniles maintain proliferating cells exclusively in the head and tail regions, not in the trunk region. Interestingly, juveniles amputated at the trunk, which lacks proliferating cells, are able to regenerate the entire head. In this process, a group of cells, which are fully differentiated, reactivates cell proliferation. Our data suggest that P. excavatus is a model system to study CNS regeneration, which is dependent on the dedifferentiation of cells. [ABSTRACT FROM AUTHOR]

A ParaHox gene cluster is composed of three genes ( Gsx, Xlox, and Cdx). It has been proposed that all three ParaHox genes were present in the last common ancestor to the lophotrochozoan protostomes and the deuterostomes and that gene loss event has occurred in the ecdysozoan lineage. In this paper, we report the existence of all three ParaHox genes in Perionyx excavatus, a clitellate annelid. Although orthologs of each of the three ParaHox genes were previously discovered from other lopotrochozoan taxa, this study constitutes the first reported isolation of all three ParaHox genes in the same clitellate species. [ABSTRACT FROM AUTHOR]