Populations Of Anaerobic Bacteria Research Articles

Topical issues of therapy for patients with ulcerative colitis

Ulcerative colitis is an autoimmune disease characterized by ulcerative destructive processes in the mucous membrane of the colon. Despite advances in the pharmaceutical industry, its prevalence in the world is increasing every year. The etiology of UC is currently unknown to the end. According to modern concepts, ulcerative colitis is considered as a multifactorial disease, in the pathogenesis of which genetic determinism, disorders of the intestinal microbiota with a decrease in populations of anaerobic bacteria in combination with the trigger action of environmental factors are discussed. With high probability, the leading pathogenetic mechanisms of the disease are associated with the polarization of the Th2-type immune response, which is characterized by the synthesis of IL-4, IL-5, IL-9 and IL-13, which is regulated by STAT-5 and Gata-3. During the development of the disease, Th17, a type of immune response, is also involved in the immunopathological process, but with the participation of transcription factors STAT-3 and ROR-yt and the synthesis of IL-17, IL-2, IL-6, IL-26 and IL-22, as well as chemokine CCL20. Diet and lifestyle are part of the global guidelines for the treatment of patients with ulcerative colitis. Derivatives of 5-aminosalicylic acid are used as basic therapy preparations: combined preparations and preparations of pure 5-aminosalicylic acid. Nevertheless, the administration of systemic glucocorticosteroids is indicated to control the activity of the disease. However, as our practice shows, they are effective, but only at the first attack and subsequent 2-3 relapses of the disease, followed by a high incidence of hormone resistance. To date, there are modern medicines with a different mechanism of action, allowing achieving stable remission and improving the quality of life of patients. Among them, JAK -tofacitinib inhibitors are of particular interest in the treatment of ulcerative colitis. This is the first oral drug capable of inducing and maintaining steroidal remission. The choice of a particular drug is determined by the experience of use, cost and national recommendations.

Colposcopic evaluation of cervix in patients with bacterial vaginosis

Background and aim Bacterial vaginosis (BV) is a clinical syndrome emerging from changing of the bacteria Lactobacillus species that produce hydrogen peroxide in the vagina with many population of anaerobic bacteria. A lot of researchers have agreed with the relation between BV and cervical intra-epithelial lesions. However, other researchers have not accepted this relation between cervical neoplasia and BV. The study aim was to evaluate the abnormal colposcopic findings associated with BV and to study the relation between BV and cervical lesions. Patients and methods This study is a cross-sectional observational one that included 246 women diagnosed as having BV using Amsle’s criteria. All participants underwent proper history taking, general and abdominal examination, local vaginal examination, and colposcopic examination. Finally, Swede score was applied to abnormal colposcopic findings. Results By naked-eye examination, there were 163 patients with normal findings and 83 patients had abnormal cervical appearance, colposcopic examination of patients revealed 14 patients with unsatisfactory findings, and 196 patients had normal findings and 36 patients had abnormal cervix. The abnormal colposcopic findings were significantly associated with urban (55.6%) than rural women (44.4%) (P=0.039), educated (72.2%) than noneducated women (27.8%) (P=0.033), nonemployed (72.2%) than employed women (27.8%) (P=0.011), and women using oral contraceptive pills (OCP) (38.9%) than other contraceptive methods (P=0.024). Conclusion Most cervical lesions associated with BV in our study were of low grade and although use of colposcopy allowed early detection and management of cervical precancerous lesions associated with BV.

Isolation of Lactobacillaceae bacteria from feces of ostrich (Struthio camelus).

The ostrich (Struthio camelus) is an herbivorous bird with a long and developed hindgut. In the hindgut, there is a dense and highly diverse population of anaerobic bacteria, and active fermentation produces high concentrations of short-chain fatty acids. Bacteria in the hindgut of the ostrich are considered vital for both their nutritional contribution and health benefits, such as benefits to the immune and defense system of the host. We attempted to isolate Lactobacillaceae, which might be involved in improving immune function and in inhibiting pathogens. The number of colonies from ostrich feces observed on LBS agar medium was 3.64×103 per gram of feces. Three strains of Lactobacillaceae were isolated from the feces. Nearly the entire length of the 16S ribosomal RNA gene of these isolates was sequenced, and a homology search showed high identity with L. brevis (identity=99.93%), L. coryniformis (98.39%), and L. paracasei (100.0%). These isolates may be deemed potential probiotics for the ostrich.

Eggshell and environmental bacteria contribute to the intestinal microbiota of growing chickens

BackgroundThe initial intestinal microbiota acquired from different sources has profound impacts on animal health and productivity. In modern poultry production practices, the source(s) of the establishing microbes and their overall contribution during development of gastrointestinal tract communities are still unclear. Using fertilized eggs from two independent sources, we assessed the impact of eggshell- and environmental-associated microbial communities on the successional processes and bacterial community structure throughout the intestinal tract of chickens for up to 6 weeks post-hatch.ResultsCulturing and sequencing techniques identified a viable, highly diverse population of anaerobic bacteria on the eggshell. The jejunal, ileal, and cecal microbial communities for the egg-only, environment-only, and conventionally raised birds generally displayed similar successional patterns characterized by increasing community richness and evenness over time, with strains of Enterococcus, Romboutsia, and unclassified Lachnospiraceae abundant for all three input groups in both trials. Bacterial community structures differed significantly based on trial and microbiota input with the exception of the egg-exposed and conventional birds in the jejunum at week 1 and the ileum at week 6. Cecal community structures were different based on trial and microbiota input source, and cecal short-chain fatty acid profiles at week 6 highlighted functional differences as well.ConclusionWe identified distinct intestinal microbial communities and differing cecal short-chain fatty acid profiles between birds exposed to the microbiota associated with either the eggshell or environment, and those of conventionally hatched birds. Our data suggest the eggshell plays an appreciable role in the development of the chicken intestinal microbiota, especially in the jejunum and ileum where the community structure of the eggshell-only birds was similar to the structure of conventionally hatched birds. Our data identify a complex interplay between the eggshell and environmental microbiota during establishment and succession within the chicken gut. Further studies should explore the ability of eggshell- and environment-derived microbes to shape the dynamics of succession and how these communities can be targeted through interventions to promote gut health and mitigate food-borne pathogen colonization in poultry.

A Small Aromatic Compound Has Antifungal Properties and Potential Anti-Inflammatory Effects against Intestinal Inflammation.

Resistance of the opportunistic pathogen Candida albicans to antifungal drugs has increased significantly in recent years. After screening 55 potential antifungal compounds from a chemical library, 2,3-dihydroxy-4-methoxybenzaldehyde (DHMB) was identified as having potential antifungal activity. The properties of DHMB were then assessed in vitro and in vivo against C. albicans overgrowth and intestinal inflammation. Substitution on the aromatic ring of DHMB led to a strong decrease in its biological activity against C. albicans. The MIC of DHMB was highly effective at eliminating C. albicans when compared to that of caspofungin or fluconazole. Additionally, DHMB was also effective against clinically isolated fluconazole- or caspofungin-resistant C. albicans strains. DHMB was administered to animals at high doses. This compound was not cytotoxic and was well-tolerated. In experimental dextran sodium sulphate (DSS)-induced colitis in mice, DHMB reduced the clinical and histological score of inflammation and promoted the elimination of C. albicans from the gut. This finding was supported by a decrease in aerobic bacteria while anaerobic bacteria populations were re-established in mice treated with DHMB. DHMB is a small organic molecule with antifungal properties and anti-inflammatory activity by exerting protective effects on intestinal epithelial cells.

Diversity of anaerobic bacteria in sediments from a subtropical reservoir

AbstractA descriptive analysis of microbial communities from two different sediment locations in a subtropical reservoir was undertaken, using DGGE and 16S rRNA gene clone library. This study evaluated bacterial diversity in the sediment of a subtropical reservoir, based on quantitative and qualitative analyses of sulphate‐reducing bacteria (SRB), denitrifying bacteria (DB) and hydrogen‐producing bacteria (HPB). The sediment samples were taken from a subtropical reservoir (Ibiúna, SP, Brazil), being collected at two contrasting sites, including (A) at a 4 m depth and (B) at an 11 m depth of the water column. The anaerobic bacteria population density in the sediment was estimated with the most probable number (MPN) method. The microbial diversity of the sediment was assessed by molecular biology analyses for the domain Bacteria. Increased cell count numbers were observed in sample A for DB. The count for sample B was higher for SRB and HPB. Both sediment communities (A and B samples) exhibited a high diversity. They were similar to the phyla Proteobacteria, Chloroflexi, Firmicutes, Actinobacteria, Cyanobacteria, Fusobacteria, Deferribacteres, Verrucomicrobia and uncultivated bacteria. The environmental conditions of sediments from tropical climates were mainly sunlight during the day and temperatures around 25 °C, which would favour the maintenance of nutrients and the available organic matter for establishing the anaerobic bacteria populations. The microbial diversity observed for both samples indicates new possibilities for application of the sediment reservoir in regard to biotechnological processes such as the operation of anaerobic reactors for wastewater and toxic compound treatment, bioenergy generation and production of biogases such as hydrogen and methane.

Effects of citrus pulp, fish by-product and Bacillus subtilis fermentation biomass on growth performance, nutrient digestibility, and fecal microflora of weanling pigs.

An experiment was conducted to investigate the effects of dietary supplementation with citrus pulp, fish by-product, and Bacillus subtilis fermentation biomass on the growth performance, apparent total tract digestibility (ATTD) of nutrients, and fecal microflora of weanling pigs. A total of 180 weaned piglets (Landrace × Yorkshire × Duroc) were randomly allotted to three treatments on the basis of body weight (BW). There were six replicate pens in each treatment with 10 piglets per pen. Dietary treatments were corn-soybean meal-based basal diet supplemented with 0 (control), 2.5, and 5.0% citrus pulp, fish by-product, and B. subtilis fermentation biomass. The isocaloric and isoproteineous experimental diets were fed in mash form in two phases (d 0 ~ 14, phase I and d 15 ~ 28, phase II). Dietary treatments had significant linear effects on gain to feed ratio (G:F) in all periods, whereas significant linear effects on ATTD of dry matter (DM), gross energy (GE), and ash were only observed in phase I. Piglets fed diet supplemented with 5.0% citrus pulp, fish by-product, and B. subtilis fermentation biomass showed greater (p < 0.05) G:F (phase I, phase II, and overall) as well as ATTD of DM, GE, and ash (phase I) than pigs fed control diet. Dietary treatments also had significant linear effects on total anaerobic bacteria populations by d 14 and 28. In addition, piglets fed diet supplemented with 5.0% citrus pulp, fish by-product and B. subtilis fermentation biomass showed greater (p < 0.05) fecal total anaerobic bacteria populations (d 14 and 28) than pigs fed control diet. Dietary treatments had no significant effects (linear or quadratic) on average daily gain (ADG), average dial feed intake (ADFI; phase I, phase II, and overall), or fecal populations of Bifidobacterium spp., Clostridium spp., and coliforms (d 14 and 28). These results indicate that dietary supplementation with 5.0% citrus pulp, fish by-product, and B. subtilis fermentation biomass has the potential to improve the feed efficiency, nutrient digestibility, and fecal microflora of weanling pigs.

High rate anaerobic digestion of wastewater separated from grease trap waste

The co-production of biodiesel and methane gas from grease trap waste (GTW) was evaluated and compared against theoretical predictions of methane production from sole anaerobic digestion of GTW. The GTW was first processed into two separate phases comprised of fats, oil, and grease (FOG) and high strength wastewater (GTW wastewater). The GTW wastewater was then anaerobically digested in biochar packed up-flow column reactors to produce methane gas and a low-strength wastewater effluent while the FOG phase was set aside for conversion into biodiesel. Anaerobic digestion efficiencies that yielded chemical oxygen demand (COD) reductions up to 95% and methane headspace concentrations between 60 and 80% were achieved along with FOG to biodiesel conversion efficiencies of 90%. Methane production yields (m3 per kg COD reduced) achieved theoretical maximums with near total depletion of the volatile organic acids. High resolution images of biochar samples confirmed extensive coverage with thick biofilm communities. Microbial analysis revealed broad spectrum populations of anaerobic bacteria that ferment organic substrates to produce acetate, ethanol, and hydrogen as major end products as well as archaeal populations that produce methane gas. Energy calculations validated the co-production of biodiesel and methane gas from GTW as a competitive option relative to its co-digestion with sewage sludge.

Inhibition of hydrogen sulfide, methane, and total gas production and sulfate-reducing bacteria in in vitro swine manure by tannins, with focus on condensed quebracho tannins

Management practices from large-scale swine production facilities have resulted in the increased collection and storage of manure for off-season fertilization use. Odor and emissions produced during storage have increased the tension among rural neighbors and among urban and rural residents. Production of these compounds from stored manure is the result of microbial activity of the anaerobic bacteria populations during storage. In the current study, the inhibitory effects of condensed quebracho tannins on in vitro swine manure for reduction of microbial activity and reduced production of gaseous emissions, including the toxic odorant hydrogen sulfide produced by sulfate-reducing bacteria (SRB), was examined. Swine manure was collected from a local swine facility, diluted in anaerobic buffer, and mixed with 1% w/v fresh feces. This slurry was combined with quebracho tannins, and total gas and hydrogen sulfide production was monitored over time. Aliquots were removed periodically for isolation of DNA to measure the SRB populations using quantitative PCR. Addition of tannins reduced overall gas, hydrogen sulfide, and methane production by greater than 90% after 7days of treatment and continued to at least 28days. SRB population was also significantly decreased by tannin addition. qRT-PCR of 16S rDNA bacteria genes showed that the total bacterial population was also decreased in these incubations. These results indicate that the tannins elicited a collective effect on the bacterial population and also suggest a reduction in the population of methanogenic microorganisms as demonstrated by reduced methane production in these experiments. Such a generalized effect could be extrapolated to a reduction in other odor-associated emissions during manure storage.

Resistance of Faecal Coliforms and Enterococci Populations in Sludge and Biosolids to Different Hygienisation Treatments

The composition of the most abundant facultative anaerobic bacteria populations [faecal coliforms (FC) and enterococci (ENT)] in sludge can be modified after different treatments. These involve the disposal or reuse of sludge and include: anaerobic digesters, incineration, composting, pasteurization and lime treatments. In this study, three treatment types (mesophilic anaerobic digestion, composting and pasteurization) were compared in terms of their ability to reduce both bacterial populations. The diversity and any changes in composition of main phenotypic groups for both populations were also analyzed. Mesophilic anaerobic digestion (MAD) was carried out at 35 degrees C for 20 days. Digested sludge was then dehydrated by centrifugation at 2,500 rpm. Composting (COM) was performed at 55 degrees C with windrow phases. Pasteurization was assayed at 60 degrees C for 90 min (P60), at 80 degrees C for 60 min (P80). A 1-1.5 log unit reduction was observed for FC, and 1 log unit reduction was noted for ENT by MAD treatment. In composting, this reduction proved higher for FC than for ENT (6 log and 3-4 log units, respectively). Optimal pasteurization was obtained at 80 degrees C for 60 min, resulting in a 5 log unit reduction for FC and a 2 log unit reduction for ENT. High diversity indices (Di) for both bacterial populations were detected both before and after implementation of the different treatments. Analyses of the population's similarity provided that FC were diverse both before and after COM, P60 and P80 treatments. However, no differences were observed on the composition of ENT populations after the different treatments assayed.

Colonization Resistance Induced in Mice Orogastrically Dosed with Human Faecal Homogenates from Different Donors

Human faecal samples from various donors were assessed for the capacity to provide protection against Salmonella typhimurium both in vitro and in vivo . Faecal material was collected from four healthy human subjects. Populations of anaerobic bacteria and enterics were enumerated using selective media and the isolates screened for the capacity to inhibit the in vitro growth of S. typhimurium . Isolates with inhibitory activity against S. typhimurium were detected in two out of four subjects. These isolates accounted for 8 and 2% of the total culturable faecal population, which corresponded to 6 x 10 8 and 2 x 10 8 CFU per g, respectively. Ex-germ-free mice (Balb/C) were dosed with faecal material and then challenged with S. typhimurium . Protection against infection was monitored by enumerating the faecal levels of the pathogen. Human flora associated mice had high faecal levels of anaerobes (10 10 CFU per g). Faecal levels of enterics in these animals ranged from 10 4 to 10 8 CFU per g. Animals dosed with human faecal material gained protection against gastrointestinal colonisation by S. typhimurium . In these animals, the faecal levels of Salmonella ranged from 1 x 10 2 to 5 x 10 5 CFU per g, compared with the levels of greater than 5 x 10 6 CFU per g in animals not previously associated with the human flora. Human faecal material containing the highest levels of inhibitory isolates provided the best protection in mice, against colonisation by S. typhimurium . Keywords: colonization resistance, germ-free.

Colonization Resistance Induced in Mice Orogastrically Dosed with Human Faecal Homogenates from Different Donors

Human faecal samples from various donors were assessed for the capacity to provide protection against Salmonella typhimurium both in vitro and in vivo. Faecal material was collected from four healthy human subjects. Populations of anaerobic bacteria and enterics were enumerated using selective media and the isolates screened for the capacity to inhibit the in vitro growth of S. typhimurium. Isolates with inhibitory activity against S. typhimurium

Anaerobic treatment of effluents from an industrial polymers synthesis plant

The feasibility of the anaerobic treatment of an industrial polymer synthesis plant effluent was evaluated. The composition of the wastewater includes acrylates, styrene, detergents, a minor amount of silicates and a significant amount of ferric chloride. The average chemical oxygen demand (COD) corresponding is about 2000mg/l. The anaerobic biodegradability of the effluent is shown and the toxicity effect on the populations of anaerobic bacteria is evaluated. The results of the anaerobic biodegradation assays show that 62% of the wastewater compounds, measured as COD, could be consumed. An upflow anaerobic sludge blanket (UASB) reactor was used in the evaluation, it has a diameter–height ratio of 1:7, and 4-liter volume. The inoculum was obtained from a UASB pilot plant that treats brewery wastewaters. At the beginning of the operation, the biomass showed an anaerobic activity of 0.58gCOD/(gVSS×d), it decreased only 2.5% in the subsequent 4 months. After 35 days of continuous operation, the reactor was operated at different steady states for 140 days. The COD was maintained at 2200mg/l in the feed. The results were: organic loading rate (OLR): 4.3kg COD/(m3×d), hydraulic retention time: 12h, superficial velocity: 1m/h, average biogas productivity: 290L CH4/kg COD fed, biogas composition: 70–75% methane and a COD removal percentage >75%. ©

Removal of volatile acids from synthetic landfill leachate by anaerobic biofilms on drainage aggregates: a laboratory study

Populations of anaerobic bacteria derived from gassing landfills were established on various solid media in laboratory-scale models of landfill drains. Solutions of salts and volatile fatty acids (VFAs), simulating landfill leachates, were circulated through the models for periods of 400 to 800 days and the removal of VFAs and the formation of gas were measured. The ability of the colonized aggregate to remove VFAs from the leachates increased to a maximum over periods of time ranging from 50 to 150 days after the initial colonization phase. The highest rates of VFA removal [3500 mg l–1 (bed vol.) day–1 at a leachate flow rate of 2.59 l d–1 with 16 500 mg l–1 total VFAs] were found at the tops of the columns, but the lower sections were also colonized by bacteria capable of removing VFAs. The initial adaptation of the bacterial population to propionic acid degradation was slower than the adaptation to acetate and butyrate degradation. Increasing the propionate concentration in the leachate from 2500 to 7500 mg l–1 caused a 50% reduction in the rate of removal of VFAs by a bacterial population adapted to a mixture of acetate, propionate and butyrate. The bacterial population eventually adapted to the higher concentrations of propionate. Changing from saturated to unsaturated flow conditions in the drainage models reduced the specific rate of removal of VFAs by 50%.

Removal of volatile acids from synthetic landfill leachate by anaerobic biofilms on drainage aggregates: a laboratory study

Populations of anaerobic bacteria derived from gassing landfills were established on various solid media in laboratory-scale models of landfill drains. Solutions of salts and volatile fatty acids (VFAs), simulating landfill leachates, were circulated through the models for periods of 400 to 800 days and the removal of VFAs and the formation of gas were measured. The ability of the colonized aggregate to remove VFAs from the leachates increased to a maximum over periods of time ranging from 50 to 150 days after the initial colonization phase. The highest rates of VFA removal [3500 mg 1-1 (bed vol.) day -1 at a leachate flow rate of 2.59 1 d-1 with 16 500 mg 1-1 total VFAs] were found at the tops of the columns, but the lower sections were also colonized by bacteria capable of removing VFAs. The initial adaptation of the bacterial population to propionic acid degradation was slower than the adaptation to acetate and butyrate degradation. Increasing the propionate concentration in the leachate from 2500 to 7500 mg 1 -1 caused a 50% reduction in the rate of removal of VFAs by a bacterial population adapted to a mixture of acetate, propionate and butyrate. The bacterial population eventually adapted to the higher concentrations of propionate. Changing from saturated to unsaturated flow conditions in the drainage models reduced the specific rate of removal of VFAs by 50%.

Biogeochemical activity of anaerobic microorganisms from buried permafrost sediments

Permafrost sediment samples, ranging in age from 7 thousand to 2 million years, from the northeastern region of Russian Arctic were analyzed for evidence of reducing conditions, viable populations of anaerobic bacteria and their metabolic end products. Field analyses of samples showed that all sediments were reduced with a redox potential ranging from +40 to —256 mV. Ferrous iron, acid‐soluble sulfide, and methane were detected in the frozen sediments. Direct bacterial counts were 107 to 108 cells/g sediments as determined by epifluorescence microscopy using acridine orange. Denitrifiers and (H2 + CO2)‐utilizing methanogens were detected in all samples, and acetoclastic methanogens, sulfate reducers, and Fe(Ill) reducers were detected in some samples and at much lower numbers. [3SS]Sulfide production from [35S]sulfate was detected in soils incubated anaerobically at 4°C for 6 months. Thus anaerobic metabolic activity was present at temperatures near freezing. These results suggest that viable anaerobic bacteria reside in aged, reduced permafrost sediments. Future investigation should focus on detecting activity in the frozen state.

Survival of methanogens in air-dried paddy field soil and their heat tolerance

Population density of methanogens in moist paddy field soil during the cultivation period of rice was usually at the order of 105 MPN g−1 (dry soil). When the soil was air-dried and preserved under oxic condition, the population of methanogens decreased to about one fourth of that in the original moist soil after four months of storage. The population density of methanogens in the air-dried soil, however, did not decrease significantly during the following storage and the population in the soil after two years was almost identical to that in the soil preserved for four months. The population of anaerobic bacteria in the air-dried soil was 34% of that in the original moist soil after two years and that of aerobic bactertia was about 1 to 3%. When slurries of various air-dried paddy field soils which were preserved for different times were incubated anaerobically in the presence of added methanogenic substrates, production of methane usually proceeded actively. When these air-dried paddy field soils were heated at various temperatures for different times and the slurries of the soils were incubated anaerobically in the same way, it was shown that methanogens surviving in the air-dried paddy field soils could withstand temperatures up to 105°c for 10hrs or 140°c for 30 min. H2-producing bacteria in the air-dried soils also endured almost the same level of heat treatment.

Survival of methanogens in airdried paddy field soil and their heat tolerance

Population density of methanogens in moist paddy field soil during the cultivation period of rice was usually at the order of 105 MPN g−1 (dry soil). When the soil was air-dried and preserved under oxic condition, the population of methanogens decreased to about one fourth of that in the original moist soil after four months of storage. The population density of methanogens in the air-dried soil, however, did not decrease significantly during the following storage and the population in the soil after two years was almost identical to that in the soil preserved for four months. The population of anaerobic bacteria in the air-dried soil was 34% of that in the original moist soil after two years and that of aerobic bactertia was about 1 to 3%. When slurries of various air-dried paddy field soils which were preserved for different times were incubated anaerobically in the presence of added methanogenic substrates, production of methane usually proceeded actively. When these air-dried paddy field soils were heated at various temperatures for different times and the slurries of the soils were incubated anaerobically in the same way, it was shown that methanogens surviving in the air-dried paddy field soils could withstand temperatures up to 105°C for 10hrs or 140°C for 30 min. H2-producing bacteria in the air-dried soils also endured almost the same level of heat treatment.

Digestion of Herring by Indigenous Bacteria in the Minke Whale Forestomach

Northeastern Atlantic minke whales (Balaenoptera acutorostrata) have a multichambered stomach system which includes a nonglandular forestomach resembling that of ruminants. Bacteria from the forestomachs of herring-eating whales were enumerated and isolated in an anaerobic rumen-like culture medium (M8W medium). The total viable population of anaerobic bacteria ranged from 73 x 10 to 145 x 10/ml of forestomach fluid (n = 4). Lactobacillus spp. (19.7%), Streptococcus spp. (35.9%), and Ruminococcus spp. (12.8%) were the most common of the bacterial strains (n = 117) isolated by use of M8W medium from the forestomach fluid population of two minke whales. Most of the isolates stained gram positive (93.2%), 62.4% were cocci, and all strains were strictly anaerobic. The population of lipolytic bacteria in one animal, enumerated by use of a selective lipid medium, constituted 89.7% of the viable population. The total viable population of anaerobic bacteria in freshly caught and homogenized herring (Clupea harengus) ranged from 56.7 to 95.0 cells per gram of homogenized prey (n = 3) when M8W medium was used. Pediococcus spp. (30.6%) and Aerococcus spp. (25.0%) were most common of the bacterial strains (n = 72) isolated from the homogenized herring. Most of the bacterial strains were gram positive (80.6%), and 70.8% were cocci. Unlike the forestomach bacterial population, as many as 61.1% of the strains from the herring were facultatively anaerobic. All bacterial strains isolated from the prey had phenotypic patterns different from those of strains isolated from the dominant bacterial population in the forestomach, indicating that the forestomach microbiota is indigenous. Scanning electron microscopic examinations revealed large numbers of bacteria, surrounded by a glycocalyx, attached to partly digested food particles in the forestomach. These data support the hypothesis that symbiotic microbial digestion occurs in the forestomach and that the bacteria are indigenous to minke whales.

Preliminary Evaluation of the Use of Methylene Blue, a Redox Dye, in the Treatment of Chronic Periodontitis

It is well established that chronic periodontitis is associated with the accumulation of subgingival plaque [1]. The microflora of this plaque is extremely complex and varies from niche to niche. Thus, the sparse subgingival flora of the healthy crevice consists largely of aerobic and facultative bacteria (mainly gram-positive cocci and rods). In gingivitis, the relative numbers of gram-negative cocci and rods increase, and in periodontitis, there is a further increase in the number of anaerobic gram-negative rods. [2]. Some of these organisms have been strongly implicated in the pathogenesis of periodontal disease; Porphyromonas gingivalis, Prevotella intermedia, Fusobacterium nucleatum, Wolinella recta, and spirochetes are examples. Current methods of treating periodontitis involve mechanical removal of plaque, with occasional adjunctive chemical therapy with agents such as chlorhexidine or the tetracyclines [3, 4]. However, antimicrobial agents are not the only means of controlling the growth of anaerobic bacteria. Survival and growth of such organisms in an ecosystem is, in part, dependent on the existence of a low redox potential [5-7]. Studies have shown that redox potentials as low as -300 mV exist in periodontal pockets, thereby enabling the survival of oral anaerobic bacteria in this ecosystem [8, 9]. The redox potential of the healthy gingival crevice has been measured by Kenney and Ash to be +70 mV [8], with a small population of anaerobic bacteria. Thus, by raising the redox potential of the periodontal pocket, it should be possible to create an environment incompatible with the growth of anaerobic periodontal pathogens. Various substances are available that might achieve this, such as redox dyes (like methylene blue) and transition metal ions (like ferric ions) [10, 11]. The aim of the present study was to determine whether