Four species in the ELEGANS group of the subgenus Caenorhabditis are distinguished by two very different mating systems: androdioecy in C. elegans and Caenorhabditis briggsae with males and self-fertilizing hermaphrodites and dioecy in Caenorhabditis remanei and Caenorhabditis sp. strain CB5161 with males and females. Using chemotaxis assays, we demonstrate that females secrete a potent sex pheromone that attracts males from a distance, whereas hermaphrodites do not. The female sex pheromone is not species-specific, with males of all four species attracted to both the C. remanei and Caenorhabditis sp. female sex pheromones. The pheromone is, however, sex-specific, with only females secreting the pheromone and attracting only males. Furthermore, the sex pheromone is stage-specific, with female secretion and male detection of the pheromone beginning near adulthood. Females lose their attractiveness immediately after mating but regain it several hours after mating ceases. Finally, the female somatic gonad is required for sex-pheromone production, and the male-specific cephalic neurons (CEM) are required for male response. chemotaxis ͉ cephalic neuron ͉ sex attractant ͉ nematode mating D irect observations show that the mating efficiency of the androdioecious species Caenorhabditis elegans is poor compared with the related dioecious species Caenorhabditis remanei and that both C. remanei and C. elegans males find C. remanei females more attractive than C. elegans hermaphrodites (1). Perhaps during evolution C. elegans hermaphrodites lost the ability to secrete a sex pheromone that is still secreted by C. remanei females and this pheromone still attracts C. elegans males. The focus of the present study is to definitively determine the presence of a sex pheromone in dioecious Caenorhabditis that is absent in related hermaphroditic species.Although C. elegans is a well-studied organism, it is yet debatable whether there is a true sex pheromone in this species, although apparently males can sense a hermaphrodite-derived chemical (2, 3). If hermaphrodites do indeed secrete a true sex pheromone, it is surprising that males do not rapidly and consistently chemotax to hermaphrodites, because C. elegans is capable of chemotaxing to both water-soluble and volatile chemicals (4). In fact, detection of sex pheromones secreted by other nematode species has been fairly straightforward (5), with the secreting female commonly establishing a gradient of attractant readily followed by conspecific males.Females, in contrast to self-fertilizing hermaphrodites, must mate with males to reproduce, and natural selection should favor those females that do so rapidly and consistently after reaching adulthood. Here, we demonstrate that females from the dioecious species C. remanei and Caenorhabditis sp. strain CB5161 attract conspecific males from a distance, whereas hermaphrodites from the androdioecious species C. elegans and Caenorhabditis briggsae do not. We then obtain, by soaking females, a supernatant solution that can attract males fr...

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Background/Aim: Over 190 million people in the world suffer from diabetes mellitus. Diabetics are 25 times more likely to have a leg amputated because of unhealing foot ulcers. Herbal medicine has been used in China to salvage the ulcerated limb. With the aim to study the efficacy of two commonly used herbs for ulcer healing, namely Radix Astragali and Radix Rehmanniae, a good animal model needs to be developed for a proper in vivo investigation. Methods: Firstly, a diabetic animal model was established by streptozotocin injection. Then standard wounds were created on the feet of the diabetic rats. Digital photographs were taken and analyzed by a novel image analysis software. Results: The average ulcer area in the Radix Rehmanniae treatment group was 11.45 mm², which was significantly smaller than the 15.12 mm² in the water treatment group (p = 0.04). Radix Astragali, on the other hand, was found to have no significant effect on ulcer shrinkage. Conclusion: Further investigation is needed for the identification of the active principles of Radix Rehmanniae.

Pheromones are critical cues for attracting mating partners for successful reproduction. Sexually mature Caenorhabditis remanei virgin females and self‐sperm‐depleted Caenorhabditis elegans hermaphrodites produce volatile sex pheromones to attract adult males of both species from afar. The chemoresponsive receptor in males has remained unknown. Here, we show that the male chemotactic behavior requires amphid sensory neurons (AWA neurons) and the G‐protein‐coupled receptor SRD‐1. SRD‐1 expression in AWA neurons is sexually dimorphic, with the levels being high in males but undetectable in hermaphrodites. Notably, srd‐1 mutant males lack the chemotactic response and pheromone‐induced excitation of AWA neurons, both of which can be restored in males and hermaphrodites by AWA‐specific srd‐1 expression, and ectopic expression of srd‐1 in AWB neurons in srd‐1 mutants results in a repulsive behavioral response in both sexes. Furthermore, we show that the C‐terminal region of SRD‐1 confers species‐specific differences in the ability to perceive sex pheromones between C. elegans and C. remanei. These findings offer an excellent model for dissecting how a single G‐protein‐coupled receptor expressed in a dimorphic neural system contributes to sex‐specific behaviors in animals.

Esophageal squamous cell carcinoma (ESCC) is the predominant subtype of esophageal cancer worldwide and highly prevalent in less developed regions. Management of ESCC is challenging and involves multimodal treatments. Patient prognosis is generally poor especially for those diagnosed in advanced disease stage. One factor contributing to this clinical dismal is the incomplete understanding of disease mechanism, for which this situation is further compounded by the presence of other limiting factors for disease diagnosis, patient prognosis and treatments. Tumor xenograft animal models including subcutaneous tumor xenograft model, orthotopic tumor xenograft model and patient-derived tumor xenograft model are vital tools for ESCC research. Establishment of tumor xenograft models involves the implantation of human ESCC cells/xenografts/tissues into immunodeficient animals, in which mice are most commonly used. Different tumor xenograft models have their own advantages and limitations, and these features serve as key factors to determine the use of these models at different stages of research. Apart from their routine use on basic research to understand disease mechanism of ESCC, tumor xenograft models are actively employed for undertaking preclinical drug screening project and biomedical imaging research.