Methyl mercaptan production by oral bacteria is thought to be one of the main causes of oral malodor. We examined the ability of periodontopathic Porphyromonas gingivalis to produce methyl mercaptan from L-methionine and found that the invasive strains W83 and W50 produced large amounts of methyl mercaptan. We cloned and sequenced the mgl gene encoding L-methionine-␣-deamino-␥-mercaptomethane-lyase (METase) from P. gingivalis W83. The structural mgl gene consisted of 1,200 bp and encoded a 43.3-kDa protein. To examine the role of methyl mercaptan in the pathogenesis of P. gingivalis, a METase-deficient mutant of P. gingivalis W83 was constructed. The methionine degradation activity and virulence of the mutant (M1217) and the parent strain (W83) in mice were compared. M1217 showed a marked decrease in the formation of methyl mercaptan from L-methionine and decreased virulence compared with the wild-type strain W83. These results suggest that methyl mercaptan not only is one of the sources of oral malodor, but may also play a role in the pathogenicity of P. gingivalis.Oral malodor is caused mainly by volatile sulfur compounds (VSCs), such as hydrogen sulfide, methyl mercaptan, and dimethyl sulfide (21). Of these VSCs, hydrogen sulfide and methyl mercaptan are predominant in mouth air. Both compounds are highly toxic, especially methyl mercaptan (21). VSCs can increase the permeability of the oral mucosa (16) and decrease protein or collagen synthesis (6,8). It is possible that the presence of methyl mercaptan within a periodontal pocket is involved in the induction or progression of periodontal disease. Coil et al. (2) reported that the increase in the ratio of methyl mercaptan to hydrogen sulfide in human gingival crevicular sites is correlated with deeper pockets or bleeding pockets. Exposure to methyl mercaptan alters protein synthesis in human gingival fibroblasts (7) and inhibits cell migration in periodontal ligament cells (11). These findings suggest that methyl mercaptan not only may be responsible for oral malodor but also may contribute to the pathogenesis of periodontal disease.Methyl mercaptan is produced from L-methionine by the enzymatic action of L-methionine-␣-deamino-␥-mercaptomethane-lyase (METase), which catalyzes the ␣,␥ elimination of L-methionine to produce ␣-ketobutyrate, methyl mercaptan, and ammonia. This enzyme is detected in anaerobic, nonoral microorganisms, such as Pseudomonas, Trichomonas, and Clostridium (4, 5, 9, 13). In addition, Porphyromonas gingivalis, a black-pigmented anaerobe, which is implicated as a major pathogen in adult periodontitis, is known to produce large amounts of methyl mercaptan in human serum (18). However, little is known about P. gingivalis METase and the role of methyl mercaptan in the pathogenesis of this organism. In this study, we cloned the mgl gene homolog encoding METase from the virulent strain P. gingivalis W83 and confirmed its nucleotide sequence. To determine the role of METase in the pathogenicity of P. gingivalis, we constructed a METase-defici...

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Ecologists have many ways to measure and monitor ecosystems, each of which can reveal details about the processes unfolding therein. Acoustic recording combined with machine learning methods for species detection can provide remote, automated monitoring of species richness and relative abundance. Such recordings also open a window into how species behave and compete for niche space in the sensory environment. These opportunities are associated with new challenges: the volume and velocity of such data require new approaches to species identification and visualization. Here we introduce a newly-initiated acoustic monitoring network across the subtropical island of Okinawa, Japan, as part of the broader OKEON (Okinawa Environmental Observation Network) project. Our aim is to monitor the acoustic environment of Okinawa's ecosystems and use these space-time data to better understand ecosystem dynamics. We present a pilot study based on recordings from five field sites conducted over a one-month period in the summer. Our results provide a proof of concept for automated species identification on Okinawa, and reveal patterns of biogenic vs. anthropogenic noise across the landscape. In particular, we found correlations between forest land cover and detection rates of two culturally important species in the island soundscape: the Okinawa Rail and Ruddy Kingfisher. Among the soundscape indices we examined, NDSI, Acoustic Diversity and the Bioacoustic Index showed both diurnal patterns and differences among sites. Our results highlight the potential utility of remote acoustic monitoring practices that, in combination with other methods can provide a holistic picture of biodiversity. We intend this project as an open resource, and wish to extend an invitation to researchers interested in scientific collaboration.

In a male-based revision of ants of the subfamily Amblyoponinae from the Southwest Indian Ocean islands (SWIO: Comoros, Madagascar, Mauritius, Mayotte, Reunion, and Seychelles), we explore and reconsider male morphological characters that distinguish genera within the group. Our investigation redefines Amblyopone Erichson sensu Brown (1960), here referred to as Amblyopone sensu lato, into three genera: Xymmer Santschi stat. rev., Amblyopone sensu stricto, Stigmatomma Roger stat. rev. All species names under Amblyopone s. l. reassign into Xymmer and Amblyopone s. s., which are small, well-defined genera, and Stigmatomma , a large group with a generic delimitation that still needs further refinement. Based on a study of male mandible characters and our scenario for mandibular evolution of the worker caste within Amblyopone s. l, we conclude that Amblyopone s. s. nests outside of XMAS ( Xymmer + Mystrium + Adetomyrma + Stigmatomma ) clade. The following names are transferred from Amblyopone s. l. to Xymmer as comb. rev. : muticus . The following names are transferred from Amblyopone s. l. to Stigmatomma as comb. rev. : amblyops , armigerum , bellii , bierigi , bruni , celata , chilense , denticulatum , elongatum , emeryi , feae , impressifrons , luzonicum , minuta , normandi , oregonense , pallipes , quadratum , reclinatum , rothneyi , santschii , saundersi , silvestrii , zwaluwenburgi ; as comb. nov. : agostii , annae , besucheti , boltoni , caliginosum , cleae , crenatum , degeneratum , egregium , electrinum , eminia , exiguum , falcatum , ferrugineum , fulvidum , ...