Relationship between vestibular lamina, dental lamina, and the developing oral vestibule in the upper jaw of the field vole (Microtus agrestis, Rodentia)

Formation of the oral vestibule is ignored in most studies on tooth development, although dental and vestibular lamina are closely related to each other. Knowledge about morphogenetic processes shaping the oral vestibule is missing almost completely. The aim of this study was to assess the developmental relationship between dental and vestibular lamina as well as formation of the oral vestibule in the upper jaw of the field vole (Microtus agrestis), a small rodent representing an attractive model species for comparative dental studies. Three-dimensional reconstruction revealed that the upper vestibular lamina of the vole joins the antemolar part of the diastemal dental lamina, similar to mouse. Later, this lamina complex regresses and the vestibular lamina is separated from the molar epithelium. Participation of the vestibular lamina in dental lamina formation, as hypothesized for mouse, therefore remains unclear. Except for increased apoptosis in the regressing diastemal dental lamina, spatial segregation of mitoses or apoptoses could be detected neither in the jaw arch epithelium nor in the adjacent mesenchyme. Therefore, in contrast to tooth primordia, apoptosis and mitosis seem to play a minor role in shaping of the upper oral vestibule. The buccal vestibule develops secondarily, probably in consequence of general growth of the head and localized differentiation of cells.     

Bacterial Populations Associated with Different Regions of the Human Colon Wall

The microorganisms associated with the undiseased human colon wall were examined in material obtained from four sudden-death victims. In traffic accident subjects (aged 45 and 16 years) the anaerobe-aerobe ratio was about 10⁴:1 in all areas of the colon examined, whereas in acute heart failure subjects (aged 74 and 46 years) the ratio was as low as 1.2:1. The flora of each individual was distinct and complex. Although the predominant anaerobes isolated were Bacteroides and Fusobacterium spp., which composed over 50% of the flora in some samples, the species isolated (indicated by morphology and glucose fermentation products) varied between individuals. Other major types observed were gram-positive nonsporing rods, including Bifidobacterium spp., and anaerobic cocci (between 8 and 20% of isolates). Clostridia were only isolated in significant numbers from one individual. Scanning electron microscopy showed that most of the organisms were present below the top surface of the mucin layer overlying the mucosa. The use of several different preparative procedures for microscopy showed a complex microbial structure within the mucus, but major variations in the bacterial populations in different areas of the colon were not found. Spiral-shaped organisms up to 60 μm long in the form of double helices were found in two subjects by scanning electron microscopy but were not isolated during the parallel bacteriological investigation. The differences between this and previous studies are discussed in relation to experimental procedures and also in contrast to results with animals that showed a particularly specialized flora associated with the colon wall.     

Resistance to Gonorrhea Possibly Mediated by Bacterial Interference

Two men with no prior history of urethritis failed to develop gonorrhea after sexual exposures to women with genital gonococcal infection. Usual methods of prophylaxis, such as antibiotics or condoms, were not employed. The aerobic bacterial flora of these men's urethras consisted of several bacteria, some of which inhibited the in vitro growth of Neisseria gonorrhoeae. The hypothesis is suggested that bacterial interference may have played a role in protecting these men from gonorrhea.     

Effects of an Antibacterial Soap on the Ecology of Aerobic Bacterial Flora of Human Skin

The effects of ad lib use of an antibacterial soap containing 1.0% trichlorocarbanilide and 0.5% trifluoromethyldichlorocarbanilide on the bacterial flora of six skin sites of 132 subjects were measured by comparison with the flora of 93 control subjects who avoided the use of topical antibacterials. Each subject was examined once. The test soap produced significant reductions in geometric mean counts of the total aerobic flora on the back, chest, forearm, calf, and foot; counts were also reduced in the axilla, but not to a significant extent. The overall reduction by the test soap on all sites was 62% (P < 0.001). Neither age nor sex influenced the effect of the soap on the flora. The antibacterial soap also reduced the prevalence of Staphylococcus aureus on the skin, mostly by virtually eliminating it from areas other than the axilla. Partial inhibition of the gram-positive flora was not accompanied by an increase in gram-negative species. The latter were found principally in the axilla; Klebsiella pneumoniae and Enterobacter aerogenes were the species most frequently found.     

阴道菌群结构分析在 宫腔粘连患者中的临床意义

目的对宫腔粘连患者菌群结构进行评价,探讨阴道微生态在宫腔粘连中的临床意义。方法选取2014年8月至2016年8月在我院计划生育病区诊断为宫腔粘连的患者100例为试验组,同期门诊100例健康体检者为对照组。对其阴道分泌物进行湿片镜检及微生态学检测,比较两组研究对象的阴道微生态情况。结果宫腔粘连组与对照组在阴道分泌物的多样性、密集度、优势菌、pH、清洁度和病原体检出率等方面比较差异有统计学意义(Ps0.05)。宫腔粘连组阴道微生态失调检出率(48%)高于对照组(31%),差异有统计学意义(P0.05)。结论宫腔粘连患者阴道微生态失调发生率明显增高,阴道微生态失调可能与宫腔粘连的发生有关。     

Quantitative Molecular Detection of Putative Periodontal Pathogens in Clinically Healthy and Periodontally Diseased Subjects

Periodontitis is a multi-microbial oral infection with high prevalence among adults. Putative oral pathogens are commonly found in periodontally diseased individuals. However, these organisms can be also detected in the oral cavity of healthy subjects. This leads to the hypothesis, that alterations in the proportion of these organisms relative to the total amount of oral microorganisms, namely their abundance, rather than their simple presence might be important in the transition from health to disease. Therefore, we developed a quantitative molecular method to determine the abundance of various oral microorganisms and the portion of bacterial and archaeal nucleic acid relative to the total nucleic acid extracted from individual samples. We applied quantitative real-time PCRs targeting single-copy genes of periodontal bacteria and 16S-rRNA genes of Bacteria and Archaea. Testing tongue scrapings of 88 matched pairs of periodontally diseased and healthy subjects revealed a significantly higher abundance of P. gingivalis and a higher total bacterial abundance in diseased subjects. In fully adjusted models the risk of being periodontally diseased was significantly higher in subjects with high P. gingivalis and total bacterial abundance. Interestingly, we found that moderate abundances of A. actinomycetemcomitans were associated with reduced risk for periodontal disease compared to subjects with low abundances, whereas for high abundances, this protective effect leveled off. Moderate archaeal abundances were health associated compared to subjects with low abundances. In conclusion, our methodological approach unraveled associations of the oral flora with periodontal disease, which would have gone undetected if only qualitative data had been determined.     

Comparison of the gut bacterial flora of start-feeding larval turbot reared under different conditions

P.D. MUNRO, A. BARBOUR AND T.H. BIRKBECK. 1994. Bacterial colonization of the gut of turbot larvae coincided with the start of feeding and the gut microflora was then dominated by Vibrio and Aeromonas species. The detection of similar bacterial isolates over several days indicated the presence of a stable microflora during the rotifer feeding stage, probably reflecting a stable flora in the rotifer culture. There was no correlation between the number of bacteria in the gut and larval survival rates; incidences of high mortalities were not associated with high numbers of recognized fish pathogens, although an Aeromonas species was implicated as an opportunistic pathogen. Potential pathogens were isolated, albeit in low numbers, from batches of apparently healthy larvae with high survival rates. It is probable that the bacterial flora plays an important role in determining the survival of larval fish and that the establishment of a beneficial flora is possible, although the criteria for such a flora have still to be elucidated.     

Some properties of frog vestibular choline acetyltransferase and acetylcholinesterase

The amount and some properties of choline acetyltransferase (ChAT) and of acetylcholinesterase (AchE) were investigated in the frog vestibule. Enzyme activities were found to be of the same order of magnitude as in frog nervous tissue and various properties of vestibular ChAT (dependence on pH, chloride and Triton X-100 activation, phosphate sensitivity) and AchE (inhibition by eserine but not by Tetraisopropylpyrophosphoramide) were also similar as those of the homologous central nervous system enzymes. Although the precise localization of ChAT and AchE is not yet certain the efferent neurotransmitter in the vertebrate vestibular sensory periphery is believed to be acetylcholine and thus the enzymes responsible for its synthesis and degradation may participate in regulating inner ear function.     

Aerobic Oral Bacteria in Healthy Captive Snakes

Cotton swab samples were taken from the ventral surface of the mouth and from the proximal esophagus from 23 captive nonpoisonous snakes. The samples were cultured and investigated for aerobic bacteria. Both the mouth and the esophagus) samples of 6 snakes were negative. When the bacterial isolates of the mouth and the esophagus of the whole snake population were compared, it was found that the flora isolated from both locations were similar. However, when the samples of individual snakes were compared it was found that the same isolates were seldom found in both the mouth and the esophagus. The most common bacteria found were Pseudomonas sp., Alcaligenes-like organisms, Gram-positive rods and Gram-positive cocci belonging to the family Micrococcaceae. Important pathogens were seldom isolated. Salmonella virchow could be found from 2 snakes. The presence of bacteriologically negative samples, great variations in the composition of the flora between individual snakes, and the occurrence of typical environmental bacteria in the oral cavity all suggest that snakes lack a specific autochtonous flora: and the bacteria isolated from the oral cavity may be occasional environmental bacteria. The source of pathogens may be the environment, too.     

Blastocystis Is Associated with Decrease of Fecal Microbiota Protective Bacteria: Comparative Analysis between Patients with Irritable Bowel Syndrome and Control Subjects

Blastocystis is a protistan parasite living in the digestive tract of many animals, including humans. This highly prevalent intestinal parasite is suspected to be linked to Irritable Bowel Syndrome (IBS), a chronic functional bowel disorder. Here, we first compared the prevalence of Blastocystis among 56 IBS patients (40 IBS with constipation (IBS-C), 9 IBS with diarrhea (IBS-D), 4 mixed IBS (IBS-M) and 3 unsubtyped IBS (IBS-U) according to the Rome III criteria) and 56 control (i.e. without any diagnosed chronic or acute gastrointestinal disorder) subjects. The highest prevalence of Blastocystis spp. was observed in the IBS group, but was only statistically significant in men (36.8% in the IBS group versus 4.8% in the control group). We then conducted a meta-analysis including epidemiological studies attempting to determine whether Blastocystis carriage could be linked to IBS, and highlighted that IBS patients had a relative risk of 2.34 to be infected by Blastocystis when compared to non-IBS subjects. We also looked for Dientamoeba fragilis, which is often associated with IBS, and identified this parasite only in some IBS patients (n = 6/56). Several studies provided evidence for a major role of the gut microbiota in the pathophysiology of IBS. Thus, we investigated the possible impact of Blastocystis carriage on the enteric bacterial community through quantification of 8 major bacterial groups from the enteric flora. Our data indicated that men with IBS-C had a significant decrease in Bifidobacterium sp. when infected by Blastocystis. Interestingly, in control subjects (i.e. without any gastrointestinal disorder) positive for Blastocystis, Faecalibacterium prausnitzii, which is known for its anti-inflammatory properties, was significantly decreased in men. Our results support the hypothesis that Blastocystis might be linked to the pathophysiology of IBS-C and intestinal flora imbalance.     

The transferrin receptor expressed by gonococcal strain FA1090 is required for the experimental infection of human male volunteers

Iron, an essential nutrient for most microorganisms, is sequestered by the host to decrease the concentration of iron available to bacterial pathogens. Neisseria gonorrhoeae , the causative agent of gonorrhoea, can acquire iron by direct interaction with human iron-binding proteins, including the serum glycoprotein, transferrin. Iron internalization from host transferrin requires the expression of a bacterial receptor, which specifically recognizes the human form of transferrin. Two gonococcal transferrin-binding proteins have been implicated in transferrin receptor function, TbpA and TbpB. We constructed a gonococcal transferrin receptor mutant without the introduction of additional antibiotic resistance markers and tested its ability to cause experimental urethritis in human male volunteers. The transferrin receptor mutant was incapable of initiating urethritis, although the same inoculum size of the wild-type parent strain, FA1090, causes urethritis in >90% of inoculated volunteers. To our knowledge, this is the first experimental demonstration that a bacterial iron acquisition system is an essential virulence factor for human infection.     

Biochar,Bentonite and Zeolite Supplemented Feeding of Layer Chickens Alters Intestinal Microbiota and Reduces Campylobacter Load

A range of feed supplements, including antibiotics, have been commonly used in poultry production to improve health and productivity. Alternative methods are needed to suppress pathogen loads and maintain productivity. As an alternative to antibiotics use, we investigated the ability of biochar, bentonite and zeolite as separate 4% feed additives, to selectively remove pathogens without reducing microbial richness and diversity in the gut. Neither biochar, bentonite nor zeolite made any significant alterations to the overall richness and diversity of intestinal bacterial community. However, reduction of some bacterial species, including some potential pathogens was detected. The microbiota of bentonite fed animals were lacking all members of the order Campylobacterales. Specifically, the following operational taxonomic units (OTUs) were absent: an OTU 100% identical to Campylobacter jejuni; an OTU 99% identical to Helicobacter pullorum; multiple Gallibacterium anatis (>97%) related OTUs; Bacteroides dorei (99%) and Clostridium aldenense (95%) related OTUs. Biochar and zeolite treatments had similar but milder effects compared to bentonite. Zeolite amended feed was also associated with significant reduction in the phylum Proteobacteria. All three additives showed potential for the control of major poultry zoonotic pathogens.     

Histopathology of Incontinence-Associated Skin Lesions: Inner Tissue Damage Due to Invasion of Proteolytic Enzymes and Bacteria in Macerated Rat Skin

A common complication in patients with incontinence is perineal skin lesions, which are recognized as a form of dermatitis. In these patients, perineal skin is exposed to digestive enzymes and intestinal bacterial flora, as well as excessive water. The relative contributions of digestive enzymes and intestinal bacterial flora to skin lesion formation have not been fully shown. This study was conducted to reveal the process of histopathological changes caused by proteases and bacterial inoculation in skin maceration. For skin maceration, agarose gel containing proteases was applied to the dorsal skin of male Sprague-Dawley rats for 4 h, followed by Pseudomonas aeruginosa inoculation for 30 min. Macroscopic changes, histological changes, bacterial distribution, inflammatory response, and keratinocyte proliferation and differentiation were examined. Proteases induced digestion in the prickle cell layer of the epidermis, and slight bleeding in the papillary dermis and around hair follicles in the macerated skin without macroscopic evidence of erosion. Bacterial inoculation of the skin macerated by proteolytic solution resulted in the formation of bacteria-rich clusters comprising numerous microorganisms and inflammatory cells within the papillary dermis, with remarkable tissue damage around the clusters. Tissue damage expanded by day 2. On day 3, the proliferative keratinocyte layer was elongated from the bulge region of the hair follicles. Application of proteases and P. aeruginosa induced skin lesion formation internally without macroscopic erosion of the overhydrated area, suggesting that the histopathology might be different from regular dermatitis. The healing process of this lesion is similar to transepidermal elimination.     

Microbiome of Pukzing Cave in India shows high antimicrobial activity against plant and animal pathogens

Pukzing cave, the largest cave of Mizoram, India was explored for bacterial diversity. Culture dependent method revealed 235 bacterial isolates using three different treatments. Identity of the microbial species was confirmed by 16S rDNA sequencing. The highest bacterial population was recovered from heat treatment (n = 97;41.2%) followed by normal (n = 79;33.6%) and cold treatment (n = 59;25.1%) indicating dominance of moderate thermophiles. Antimicrobial potential of isolates showed 20.4% isolates having antimicrobial ability against tested pathogens. Amplicon sequencing of PKSI, PKSII and NRP specific genes revealed presence of AMP genes in the microbial population. Six microbial pathogens were selected for screening as they are well known for different disease cause organism in various fields such as agriculture and human health. Cave environment harbors unique microbial flora and hypervariable region V4 is more informative. Higher activity of AMP assay against these microbes indicates that cave microbial communities could be potential source of future genomic resources.     

Bacteriological analysis of saliva from partially or fully engorged female adult <Emphasis Type="Italic">Rhipicephalus microplus</Emphasis> by next-generation sequencing

Tick-borne diseases are a major epidemiological problem worldwide. The aim of this study was to investigate the bacterial composition of saliva obtained from engorged adult Rhipicephalus microplus females. Saliva samples collected from partially or fully engorged adult female ticks were analysed using an ultra-high-throughput Illumina HiSeq 2500 sequencing system. To elucidate the possible routes of bacterial transmission, the bacterial flora from whole ticks were also investigated. Proteobacteria, Firmicutes, and Actinobacteria were the predominant phyla in all samples, and Acinetobacter, Rickettsia, Escherichia and Coxiella were the major genera. Microbial diversity in saliva samples from partially engorged ticks was more complex than that of samples from fully engorged individuals. The comparison of saliva and whole-tick samples suggests that bacteria in saliva also colonize the tick’s body. We believe that some bacterial genera, such as Dermacoccus, Achromia, SMB53, Sutterella, Providencia, Mycoplana, Oscillospira, and Agrobacterium, were found and reported in ticks for the first time. The Coxiella and Rickettsia detected in this study might be tick-borne pathogens, suggesting health risks associated with exposure to R. microplus in humans and animals. These findings may serve as the basis for developing strategies to control ticks and tick-borne diseases.     

Tracking Microbial Contamination in Retail Environments Using Fluorescent Powder - A Retail Delicatessen Environment Example

Cross contamination of foodborne pathogens in the retail environment is a significant public health issue contributing to an increased risk for foodborne illness. Ready-to-eat (RTE) processed foods such as deli meats, cheese, and in some cases fresh produce, have been involved in foodborne disease outbreaks due to contamination with pathogens such as Listeria monocytogenes. With respect to L. monocytogenes, deli slicers are often the main source of cross contamination. The goal of this study was to use a fluorescent compound to simulate bacterial contamination and track this contamination in a retail setting. A mock deli kitchen was designed to simulate the retail environment. Deli meat was inoculated with the fluorescent compound and volunteers were recruited to complete a set of tasks similar to those expected of a food retail employee. The volunteers were instructed to slice, package, and store the meat in a deli refrigerator. The potential cross contamination was tracked in the mock retail environment by swabbing specific areas and measuring the optical density of the swabbed area with a spectrophotometer. The results indicated that the refrigerator (i.e. deli case) grip and various areas on the slicer had the highest risk for cross contamination. The results of this study may be used to develop more focused training material for retail employees. In addition, similar methodologies could also be used to track microbial contamination in food production environments (e.g. small farms), hospitals, nursing homes, cruise ships, and hotels.     

Intracellular bacterial communities of uropathogenic Escherichia coli in urinary tract pathogenesis

Urinary tract infections in young, healthy women frequently recur, despite their traditional classification as acute infections. Conventional wisdom dictates that uropathogens causing recurrent infections in such individuals come from the fecal or vaginal flora, in the same manner as the initial infection. However, recent studies of uropathogenic Escherichia coli have found that it can carry out a complex developmental program within the superficial epithelial cells of the mouse bladder, forming intracellular bacterial communities with many biofilm-like properties. These intracellular biofilms allow the bacteria to outlast a strong host immune response to establish a dormant reservoir of pathogens inside the bladder cells. Re-emergence of bacteria from this reservoir might be the source of recurrent infection.     

Relationship between opposite changes of vaginal and vestibular impedance during estrous cycle in sows

Several bioimpedance techniques have been developed for noninvasive monitoring of reproductive events occurring in cyclic gilts and sows. Our objective was to compare the changes of vaginal and vestibular impedance during the porcine estrous cycle (experiment 1). In addition, we examined the causes of impedance variations in the vaginal vestibule during periestrus (experiment 2). The vaginal and vestibular impedance were measured with specially designed instruments. Sows were monitored for estrus via exposure to a sexually mature boar. The impedance in the vagina decreased gradually after weaning (P<0.01) reaching its nadir 2 days before estrus and increased during estrus to near maximum 2 days after estrus onset (P<0.01). The vaginal impedance during diestrus reached approximately the same level as on the weaning day. In contrast, the impedance in the vaginal vestibule increased gradually after weaning, then markedly during estrus (P<0.01) reaching its maximum 2 days after the onset of estrus followed by an abrupt decrease during early diestrus (P<0.01). The vestibular impedance after early diestrus reached almost the same level as before estrus. A significant negative correlation was found between the vaginal impedance in proestrus and vestibular impedance in periestrus. In experiment 2, interaction of the interval from weaning to estrus and parity significantly influenced the vestibular impedance in periestrus. The breed of sows did not affect the impedance in the vaginal vestibule through the whole experiment. From the present study we conclude that closely related inverse changes of the vaginal and vestibular impedance take place in pigs during the estrous cycle.