RESUMO
Accurately recognizing pathogens by the host is vital for initiating appropriate immune response against infecting microorganisms. Caenorhabditis elegans has no known receptor to recognize pathogen-associated molecular pattern. However, recent studies showed that nematodes have a strong specificity for transcriptomes infected by different pathogens, indicating that they can identify different pathogenic microorganisms. However, the mechanism(s) for such specificity remains largely unknown. In this study, we showed that the nematophagous fungus Purpureocillium lavendulum can infect the intestinal tract of the nematode C. elegans and the infection led to the accumulation of reactive oxygen species (ROS) in the infected intestinal tract, which suppressed fungal growth. Co-transcriptional analysis revealed that fungal genes related to anaerobic respiration and ethanol production were up-regulated during infection. Meanwhile, the ethanol dehydrogenase Sodh-1 in C. elegans was also up-regulated. Together, these results suggested that the infecting fungi encounter hypoxia stress in the nematode gut and that ethanol may play a role in the host-pathogen interaction. Ethanol production in vitro during fungal cultivation in hypoxia conditions was confirmed by gas chromatography-mass spectrometry. Direct treatment of C. elegans with ethanol elevated the sodh-1 expression and ROS accumulation while repressing a series of immunity genes that were also repressed during fungal infection. Mutation of sodh-1 in C. elegans blocked ROS accumulation and increased the nematode's susceptibility to fungal infection. Our study revealed a new recognition and antifungal mechanism in C. elegans. The novel mechanism of ethanol-mediated interaction between the fungus and nematode provides new insights into fungal pathogenesis and for developing alternative biocontrol of pathogenic nematodes by nematophagous fungi. IMPORTANCE Nematodes are among the most abundant animals on our planet. Many of them are parasites in animals and plants and cause human and animal health problems as well as agricultural losses. Studying the interaction of nematodes and their microbial pathogens is of great importance for the biocontrol of animal and plant parasitic nematodes. In this study, we found that the model nematode Caenorhabditis elegans can recognize its fungal pathogen, the nematophagous fungus Purpureocillium lavendulum, through fungal-produced ethanol. Then the nematode elevated the reactive oxygen species production in the gut to inhibit fungal growth in an ethanol dehydrogenase-dependent manner. With this mechanism, novel biocontrol strategies may be developed targeting the ethanol receptor or metabolic pathway of nematodes. Meanwhile, as a volatile organic compound, ethanol should be taken seriously as a vector molecule in the microbial-host interaction in nature.
RESUMO
OBJECTIVE: To compare the early postoperative complications of non-penetrating trabecular surgery (NPTS) and modified trabeculectomy (MT) in patients with primary open angle glaucoma, and to analyze the cost-effectiveness of NPTS to prevent adverse events as well. METHODS: One hundred and forty seven consecutive cases (215 eyes) with primary open angle glaucoma from the glaucoma division, Zhongshan Ophthalmic Center, were involved. One hundred and four eyes underwent NPTS; while 111 eyes underwent MT. Visual acuity, intraocular pressure and complications occurred while staying in the hospital, were recorded. Number of need to treat (NNT) was used to analyze the cost-effective for NPTS. RESULTS: (1) Visual acuity decrease over 2 lines occurred in 25 eyes (24.0%) in NPTS group and 26 eyes (23.4%) in MT group. The difference of visual changes between these two groups was not statistically significant (P > 0.05). (2) One day after the operation, hypotension [IOP less or equal to 5 mm Hg (1 mm Hg = 0.133 kPa)] occurred in 39 eyes in NPTS group (38.2%), and 10 eyes in MT group (9.2%). The difference was significant (P < 0.01). On the day of discharge, the incidence of hypotension was 27.5% in NPTS group and 17.3% in MT group, respectively. The difference was still significant (P < 0.05). (3) Hyphema was found in 20 eyes (19.2%) in NPTS group and ten eyes (9.0%) in MT group. In either group, a surgical procedure was needed in two eyes to evacuate the blood. (4) Two eyes of grade II degrees and five eyes of grade I degrees shallow chamber were found in NPTS group. Five eyes of grade II degrees and five eyes of grade I shallow chamber were found in MT group. The difference of incidence of shallow chamber between these two groups was not statistically significant (P > 0.05). (5) Other complications: In the NPTS group, trabeculo-descemetic membrane rupture occurred in one eye, pupil dilated to 7 mm observed in six eyes; in the MT group, acute elevated IOP occurred in one eye, peripheral anterior synechia at inner incision occurred in one eye, hypotensive macular edema occurred in one eye. (6) The absolute risk ratio (ARR) of NPTS for adverse event was 3.0%, (NNT = 33.2), it costs additional RMB yen 116, 100 for preventing one adverse event. For serious adverse event, ARR = 1.8% (NNT = 55.5), and it costs additional RMB yen 194, 000 to prevent one serious adverse event. CONCLUSIONS: Although the NPTS may reduce the incidence of serious adverse event in comparing with MT, the cost of NPTS is very high, therefore, it is not an optimal procedure in China. Ophthalmologists in the general hospital should familiar with the MT procedure to save the medical expenses.
