Nitrogen Metabolism Genes from Temperate Marine Sediments

In this study, we analysed metagenomes along with biogeochemical profiles from Skagerrak (SK) and Bothnian Bay (BB) sediments, to trace the prevailing nitrogen pathways. NO₃ ^? was present in the top 5 cm below the sediment-water interface at both sites. NH₄ ⁺ increased with depth below 5 cm where it overlapped with the NO₃ ^? zone. Steady-state modelling of NO₃ ^? and NH₄ ⁺ porewater profiles indicates zones of net nitrogen species transformations. Bacterial protease and hydratase genes appeared to make up the bulk of total ammonification genes. Genes involved in ammonia oxidation (amo, hao), denitrification (nir, nor), dissimilatory NO₃ ^? reduction to NH₄ ⁺ (nfr and otr) and in both of the latter two pathways (nar, nap) were also present. Results show ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA) are similarly abundant in both sediments. Also, denitrification genes appeared more abundant than DNRA genes. 16S rRNA gene analysis showed that the relative abundance of the nitrifying group Nitrosopumilales and other groups involved in nitrification and denitrification (Nitrobacter, Nitrosomonas, Nitrospira, Nitrosococcus and Nitrosomonas) appeared less abundant in SK sediments compared to BB sediments. Beggiatoa and Thiothrix 16S rRNA genes were also present, suggesting chemolithoautotrophic NO₃ ^? reduction to NO₂ ^? or NH₄ ⁺ as a possible pathway. Our results show the metabolic potential for ammonification, nitrification, DNRA and denitrification activities in North Sea and Baltic Sea sediments.     

Ammonium inhibition through the decoupling of acidification process and methanogenesis in anaerobic digester revealed by high throughput sequencing

Objective

To reveal the shifts of microbial communities along ammonium gradients, and the relationship between microbial community composition and the anaerobic digestion performance using a high throughput sequencing technique.

Results

Methane production declined with increasing ammonium concentration, and was inhibited above 4 g l^?1. The volatile fatty acids, especially acetate, accumulated with elevated ammonium. Prokaryotic populations showed different responses to the ammonium concentration: Clostridium, Tepidimicrobium, Sporanaerobacter, Peptostreptococcus, Sarcina and Peptoniphilus showed good tolerance to ammonium ions. However, Syntrophomonas with poor tolerance to ammonium may be inhibited during anaerobic digestion. During methanogenesis, Methanosarcina was the dominant methanogen.

Conclusion

Excessive ammonium inhibited methane production probably by decoupling the linkage between acidification process and methanogenesis, and finally resulted in different performance in anaerobic digestion.

     

Composition and abundance of microbiota in the pharynx in patients with laryngeal carcinoma and vocal cord polyps

The pharynx is an important site of microbiota colonization, but the bacterial populations at this site have been relatively unexplored by culture-independent approaches. The aim of this study was to characterize the microbiota structure of the pharynx. Pyrosequencing of 16S rRNA gene libraries was used to characterize the pharyngeal microbiota using swab samples from 68 subjects with laryngeal cancer and 28 subjects with vocal cord polyps. Overall, the major phylum was Firmicutes, with Streptococcus as the predominant genus in the pharyngeal communities. Nine core operational taxonomic units detected from Streptococcus, Fusobacterium, Prevotella, Granulicatella, and Veillonella accounted for 21.3% of the total sequences detected. However, there was no difference in bacterial communities in the pharynx from patients with laryngeal cancer and vocal cord polyps. The relative abundance of Firmicutes was inversely correlated with Fusobacteria, Proteobacteria, Actinobacteria, and Bacteroidetes. The correlation was evident at the genus level, and the relative abundance of Streptococcus was inversely associated with Fusobacterium, Leptotrichia, Neisseria, Actinomyces, and Prevotella. This study presented a profile for the overall structure of the microbiota in pharyngeal swab samples. Inverse correlations were found between Streptococcus and other bacterial communities, suggesting that potential antagonism may exist among pharyngeal microbiota.     

Nitrification in intertidal sponge <Emphasis Type="Italic">Cinachyrella cavernosa</Emphasis>

The nitrification process in different sections of the sponges remains unresolved, despite several studies on the nitrogen cycling pathways in the tissues of temperate and Arctic sponges. In this study, the abundance, diversity and activity of the associated nitrifying organisms in intracellular, intercellular, extracellular and cortex of a tropical intertidal sponge, Cinachyrella cavernosa, were investigated using most probable number, next-generation sequencing and incubation method, respectively. The nitrification rate and the abundance of nitrifying bacteria showed significant difference among different sections. The nitrification rate in C. cavernosa was 2–12× higher than the reported values in other sponge species from temperate and Arctic regions. Nitrification rate in sponge cortex was 2× higher than in intercellular and extracellular sections. Ammonium and nitrite oxidisers ranged from 10³ to 10⁴ CFU g^?1 in the sponge with a high number of ammonium and nitrite oxidisers in the cortex. Nitrifiers belonging to Nitrosomonas, Nitrospira, Nitrospina, Nitrobacter and Nitrosopumilus were present in different sections of the sponge, with nitrifying archaea dominating the intracellular section and nitrifying bacteria dominating other sections. This study reports for the first time the nitrification inside the sponge cells. The study also suggests that the intertidal sponge, C. cavernosa, harbours metabolically active nitrifiers in different sections of the sponge body with different rates of nitrification. Thus, nitrifiers play an important role in ammonia detoxification within the sponge and also contribute to the nitrogen budget of the coastal ecosystem.     

Response of dominant grassland species in the temperate steppe of Inner Mongolia to different land uses at leaf and ecosystem levels

In order to study the responses of dominant species to different land uses in the semiarid temperate grassland of Inner Mongolia, we tested the physiological responses of Stipa grandis, Leymus chinensis, and Artemisia frigida to mowing, grazing exclusion, and grazing land uses at the leaf and ecosystem levels. The grazing-exclusion and mowing sites released CO₂, but the grazing site was a net carbon sink. L. chinensis and S. grandis contributed more to the ecosystem CO₂ exchange than A. frigida. At the grazing-exclusion and mowing sites, Leymus chinensis and Stipa grandis both exhibited a higher light-saturation point and higher maximum photosynthetic rate than that at the grazing site, which increased photosynthesis and growth compared to those at the grazing site. In contrast, A. frigida possessed a higher nitrogen content than the other species, and more of the light energy used for photosynthesis, particularly at the grazing site.     

Antimicrobial Efficacy of Synthetic Pyranochromenones and (Coumarinyloxy)acetamides

Four (1, 2, 4 and 6) synthetic quaternary ammonium derivatives of pyranochromenones and (coumarinyloxy)acetamides were synthesized and investigated for their antimicrobial efficacy on MRSA (Methicillin-resistant Staphylococcus aureus), and multi-drug resistant Pseudomonas aeruginosa, Salmonella enteritidis and Mycobacterium tuberculosis H37Rv strain. One of the four compounds screened i.e. N,N,N-triethyl-10-((4,8,8-trimethyl-2-oxo-2,6,7,8-tetrahydropyrano[3,2-g]chromen-10-yl)oxy)decan-1-aminium bromide (1), demonstrated significant activity against S. aureus, P. aeruginosa and M. tuberculosis with MIC value of 16, 35, and 15.62 µg/ml respectively. The cytotoxicity evaluation of compound 1 on A549 cell lines showed it to be a safe antimicrobial molecule, TEM study suggested that the compound led to the rupture of the bacterial cell walls.     

The carnivoran community from the Miocene of Sandelzhausen (Germany)

From the Bavarian Early/Middle Miocene (MN5) site Sandelzhausen, nine species of carnivoran mammals are identified including the hemicyonine ursid Hemicyon stehlini, the amphicyonids Amphicyon cf. major and Pseudarctos bavaricus, the mustelids Ischyrictis zibethoides and Martes cf. munki, the mephitid Proputorius pusillus, the viverrid Leptoplesictis cf. aurelianensis, the felid Pseudaelurus romieviensis, and finally the recently described barbourofelid Prosansanosmilus eggeri. With these taxa present, Sandelzhausen shows a carnivoran community typical, though deprived, for the Lower to Middle Miocene of Europe, but different from roughly contemporary Mediterranean faunas such as those from Çandir or Pa?alar in Turkey.     

Dynamics of the composition of a microbial consortium during start-up of a single-stage constant flow laboratory nitritation/anammox setup

Dynamics of the composition of the microbial community was studied during start-up of a single-stage completely mixed constant flow laboratory setup for ammonium removal by the nitritation/anammox process from the filtrate of digested sludge of the Kuryanovo wastewater treatment plant (KWTP), Moscow. To decrease the period of the start-up, the setup was initially inoculated with two types of activated sludge (nitrifying sludge from a KWTP aeration tank and sludge from a sequencing batch reactor enriched with anammox bacteria). The start-up and adjustment stage was therefore decreased to 35–40 days, and nitrogen removal efficiency reached 80% after 120 days of the setup operation. Taxonomic analysis of the composition of the microbial community was carried out by pyrosequencing of the 16S rRNA fragments obtained using the universal and planctomycetes-specific primers. In the course of adaptation of activated sludge to increasing nitrogen load, microbial community of the setup became less diverse and more specialized. The contribution of anammox bacteria of the family Brocadiaceae, closely related to Candidatus “Brocadia caroliniensis,” increased gradually. Members of the order Nitrosomonadales were involved in ammonium oxidation to nitrite. While nitrite-oxidizing bacteria of the genus Nitrospira were also detected, their share decreased with accumulation of the activated sludge. The contribution of other bacteria varied as well: the shares of the phyla Ignavibacteria, Chloroflexi, and Acidobacteria increased significantly (up to 13, 12, and 10%, respectively of the total number of reads), while relative abundance of the Proteobacteria, Bacteroidetes, Actinobacteria, Firmicutes, Synergistetes, Aminicenantes, Thermotogae, and Cloacimonetes decreased. Thus, application of pyrosequencing made it possible to monitor succession of the bacterial community involved in nitrogen removal by nitritation/anammox process.     

Genotypic characterization of Lactic acid bacteria in gut microbiome of freshwater fish

The present study focused on identification and genotypic characterization of Lactic acid bacteria (LAB) in the intestine of freshwater fish. 76 strains of LAB were isolated and identified by 16S rRNA gene sequences and hsp60 gene sequences as different strains of Lactobacillus plantarum, Lactobacillus pentosus, Lactobacillus fermentum, Lactobacillus delbrueckii subsp. bulgaricus, Lactobacillus brevis, Lactobacillus reuteri, Lactobacillus salivarius, Pediococcus pentosaceus, Pediococcus acidilactici, Weissella paramesenteroides, Weissella cibaria, Enterococcus faecium, and Enterococcus durans. The hsp60 gene showed a higher level of sequence variation among the isolates examined, with lower interspecies sequence similarity providing more resolutions at the species level than the 16S rRNA gene. Phylogenetic tree derived from hsp60 gene sequences with higher bootstrap values at the nodal branches was more consistent as compared to phylogenetic tree constructed from 16S rRNA gene sequences. Closely related species L. plantarum and L. pentosus as well as species L. delbrueckii subsp. bulgaricus and L. fermentum were segregated in different cluster in hsp60 phylogenetic tree whereas such a distribution was not apparent in 16S rRNA phylogenetic tree. In silico restriction analysis revealed a high level of polymorphism within hsp60 gene sequences. Restriction pattern with enzymes AgsI and MseI in hsp60 gene sequences allowed differentiation of all the species including closely related species L. plantarum and L. pentosus, E. faecium and E. durans. In general, hsp60 gene with higher evolutionary divergence proved to be a better phylogenetic marker for the group LAB.     

Comprehensive dataset of mangrove tree weights in Southeast Asia

We assembled a dataset tabulating the weights of Thai and Indonesian mangrove trees that we measured between 1982 and 2001. We selected four Thai study sites in Phang Nga, Ranong, Satun, and Trat Provinces and one site in eastern Indonesia on Halmahera Island in Maluku Province. The stands in Ranong Province and on Halmahera Island were in primary forests with data collected in the 1980s and the remaining stands were in secondary forests with data collected later. We collected 124 tree samples from ten species (Avicennia alba, Bruguiera cylindrica, B. gymnorrhiza, Ceriops tagal, Rhizophora apiculata, R. mucronata, Sonneratia alba, S. caseolaris, Xylocarpus granatum, and X. moluccensis) and measured the root weights of 32 individuals of nine species (A. alba, B. cylindrica, B. gymnorrhiza, C. tagal, R. apiculata, R. mucronata, S. alba, S. caseolaris, and X. granatum). All sampled trees were subjected to a standardized protocol to obtain aboveground weights. The trunks were divided into horizontal segments from which the leaves and branches were collected separately. Roots were collected by winching them out of the ground, by trench digging, or by complete excavation. Thus, we were able to compile the weights of the trunk, branches, leaves, and roots of each tree sampled. Aerial roots were included in root weight measurements, although they were collected above ground. We compiled separate lists of trunk diameters, trunk heights, heights of the lowest living branches, and the heights of aerial roots on the trunks of trees in different size categories. Our dataset includes a wide range of tree sizes (maximum trunk diameter 48.9 cm), geographical locations (1°10′N–12°24′N, 98°32′E–123°49′E) and organ weights (trunks, branches, leaves, and roots), and therefore should prove useful in future biomass studies of mangrove forests.     

New Zealand Eocene,Oligocene and Miocene Macrofossil and Pollen Records and Modern Plant Distributions in the Southern Hemisphere

The modern New Zealand flora has a relatively low number of families and genera in relation to land area, but well-preserved macrofossils and pollen from three sites in southern New Zealand suggest that the floras in Eocene, Oligocene and Miocene times were much more diverse at the generic level. At Pikopiko, Southland, a late Eocene in situ forest with fern understory was dominated by conifers, Casuarinaceae, Lauraceae, Nothofagus, Proteaceae, and mesothermal angiosperms including palms (aff. Calamus), Sapindaceae: Cupaniae and Picrodendraceae. At Newvale Mine, Southland, a leaf bed within a thick lignite seam represents leaf fossils preserved in a late Oligocene oligotrophic bog. This site demonstrates that Agathis, Dacrycarpus, Dacrydium, Halocarpus, Microcachrys, Podocarpus and Phyllocladus coexisted with diverse angiosperms including Nothofagus, Gymnostoma, Cunoniaceae, Ericaceae, Sapindaceae and several Proteaceae. Pollen data add Meliaceae, Myrtaceae, Onagraceae and Rubiaceae to the flora. At Foulden Maar, Otago, mummified leaves and flowers, including several with in situ pollen, demonstrate the existence of a diverse flora surrounding an Early Miocene lake. This site contains numerous monocot macrofossils including Astelia, Cordyline, Ripogonum and Typha, as well as the oldest fossils known for Orchidaceae and Luzuriagaceae. This flora was dominated by Lauraceae with affinities to Cryptocarya and Litsea, but other families include Araliaceae, Cunoniaceae, Elaeocarpaceae, Euphorbiaceae sensu lato, Menispermaceae, Myrsinaceae, Myrtaceae, Onagraceae, Proteaceae and Sterculiaceae. Many ferns, conifers, and Nothofagus are from lineages with Gondwanan ancestors, whereas other taxa show links to Australia (e.g., Gyrostemonaceae), New Caledonia (e.g., Beauprea) and South America (e.g., Luzuriaga, Fuchsia). Many of these taxa are now extinct in New Zealand, and therefore indicate much wider biogeographic ranges for many families and genera in the past.     

Comparative ecology of Ostracoda (Crustacea) in two rheocrene springs (Bolu,Turkey)

A total of ten taxa belonging to the class Ostracoda of the Crustacea (Darwinula stevensoni, Candona neglecta, Cypria ophthalmica, Ilyocypris bradyi, Prionocypris zenkeri, Herpetocypris chevreuxi, Psychrodromus olivaceus, Heterocypris incongruens, Scottia pseudobrowniana, Eucypris sp.) were collected from two rheocrene Darwinula stevensoni springs (Çetin Bey and Çaygökp?nar springs) on 15 separate occasions between November 2002 and November 2004. Almost all of the species identified exhibit cosmopolitan distributions – at least in the Holarctic region. The presence of Scottia pseudobrowniana represents the second recording of this species in the ostracod fauna of Turkey. The dominant taxa in both springs was Cy. ophthalmica, I. bradyi, Pr. zenkeri and Ca. neglecta. Correlation analyses suggested a significant positive relationship in relative abundance between I. bradyi, Pr. zenkeri and Cy. ophthalmica. Species composition differed significantly between the upper and lower study sites for each spring, but differences could not be detected between sites at the same elevation across sites. Environmental tolerance index (ETI) values suggest that species with high optima and tolerance ranges show cosmopolitan characteristics.     

Variability,stability, and resilience of fecal microbiota in dairy cows fed whole crop corn silage

The microbiota of whole crop corn silage and feces of silage-fed dairy cows were examined. A total of 18 dairy cow feces were collected from six farms in Japan and China, and high-throughput Illumina sequencing of the V4 hypervariable region of 16S rRNA genes was performed. Lactobacillaceae were dominant in all silages, followed by Acetobacteraceae, Bacillaceae, and Enterobacteriaceae. In feces, the predominant families were Ruminococcaceae, Bacteroidaceae, Clostridiaceae, Lachnospiraceae, Rikenellaceae, and Paraprevotellaceae. Therefore, Lactobacillaceae of corn silage appeared to be eliminated in the gastrointestinal tract. Although fecal microbiota composition was similar in most samples, relative abundances of several families, such as Ruminococcaceae, Christensenellaceae, Turicibacteraceae, and Succinivibrionaceae, varied between farms and countries. In addition to the geographical location, differences in feeding management between total mixed ration feeding and separate feeding appeared to be involved in the variations. Moreover, a cow-to-cow variation for concentrate-associated families was demonstrated at the same farm; two cows showed high abundance of Succinivibrionaceae and Prevotellaceae, whereas another had a high abundance of Porphyromonadaceae. There was a negative correlation between forage-associated Ruminococcaceae and concentrate-associated Succinivibrionaceae and Prevotellaceae in 18 feces samples. Succinivibrionaceae, Prevotellaceae, p-2534-18B5, and Spirochaetaceae were regarded as highly variable taxa in this study. These findings help to improve our understanding of variation and similarity of the fecal microbiota of dairy cows with regard to individuals, farms, and countries. Microbiota of naturally fermented corn silage had no influence on the fecal microbiota of dairy cows.     

Screening of rice landraces (<Emphasis Type="Italic">Oryza sativa</Emphasis> L.) for seedling stage salinity tolerance using morpho-physiological and molecular markers

Traditional rice landraces of coastal area in Bangladesh are distinct regarding their phenotype, response to salt stress and yield attributes. With characterization of these landraces, suitable candidate genes for salinity tolerance could be identified to introgress into modern rice varieties. Therefore, the aim of this experiment was to uncover prospective rice landraces tolerant to salinity. Relying on morphological, biochemical and molecular parameters 25 rice genotypes were tested for salt tolerance at germination and seedling stage. At germination stage 0 and 12 dSm^?1 salinity were imposed on rice genotypes. Ward’s cluster analysis divided rice genotypes into three clusters (susceptible, moderately tolerant and tolerant) based on the physiological indices. The tolerant rice landraces to salinity were Sona Toly, Nakraji and Komol Bhog. At seedling stage screening was performed following IRRI standard protocol at 12 dSm^?1 salinity level. Based on all morphological and biochemical parameters Komol Bhog was identified as the highly salinity tolerant landrace while Bolonga, Sona Toly, Dud Sail, Tal Mugur and Nakraji were found as tolerant to salinity. Molecular characterization using two simple sequence repeats (SSR) markers, viz. RM121 and RM337 displayed Bolonga, Til Kapor, Panbra, Sona Toly, Bina Sail, Komol Bhog, Nakraji, Tilkapur, Gajor Goria and Gota were tolerant landraces through genetic similarity in dendrogram. These identified salt-resistant landraces can be used as promising germplasm resources for breeding salt-tolerant high-yielding rice varieties in future.     

Mycorrhizal detection of native and non-native truffles in a historic arboretum and the discovery of a new North American species, <Emphasis Type="Italic">Tuber arnoldianum</Emphasis> sp. nov.

During a study comparing the ectomycorrhizal root communities in a native forest with those at the Arnold Arboretum in Massachusetts (USA), the European species Tuber borchii was detected on the roots of a native red oak in the arboretum over two successive years. Since T. borchii is an economically important edible truffle native to Europe, we conducted a search of other roots in the arboretum to determine the extent of colonization. We also wanted to determine whether other non-native Tuber species had been inadvertently introduced into this 140-year-old Arboretum because many trees were imported into the site with intact soil and roots prior to the 1921 USDA ban on these horticultural practices in the USA. While T. borchii was not found on other trees, seven other native and exotic Tuber species were detected. Among the North American Tuber species detected from ectomycorrhizae, we also collected ascomata of a previously unknown species described here as Tuber arnoldianum. This new species was found colonizing both native and non-native tree roots. Other ectomycorrhizal taxa that were detected included basidiomycetes in the genera Amanita, Russula, Tomentella, and ascomycetes belonging to Pachyphlodes, Helvella, Genea, and Trichophaea. We clarify the phylogenetic relationships of each of the Tuber species detected in this study, and we discuss their distribution on both native and non-native host trees.     

First molecular detection of <Emphasis Type="Italic">Anaplasma phagocytophilum</Emphasis> in the hard tick <Emphasis Type="Italic">Rhipicephalus haemaphysaloides</Emphasis> in Taiwan

Anaplasma phagocytophilum is transmitted mainly by hard ticks and can cause potentially fatal granulocytic anaplasmosis in humans, but its occurrence in ticks in Taiwan has never been investigated although this pathogen has been detected in Taiwanese rodents before. Ticks collected from small mammals in Hualien, eastern Taiwan, were assayed for Anaplasma infections; infections of Rickettsia and Apicomplexa protozoans were also studied. Of the 270 individually assayed Rhipicephalus haemaphysaloides ticks, A. phagocytophilum was identified in a nymphal tick. Parasites most similar to Anaplasma bovis, Rickettsia rickettsii, Rickettsia sp. TwKM01, and at least seven apicomplexan species (including genera Cryptosporidium, Hepatozoon, and Theileria) were also identified. This study shows that A. phagocytophilum does occur in the hard tick in Taiwan, although whether R. haemaphysaloides can vector this pathogen remains to be determined. This work also reveals a high diversity of tick-borne bacteria and protozoans circulating in a small region and calls for further research on their potential risks for human health.     

Molecular analyses of <Emphasis Type="Italic">Ficus erecta</Emphasis> and its allies within the subsection <Emphasis Type="Italic">Frutescentiae</Emphasis> (Moraceae)

Ficus (Moraceae) is a keystone group in tropical and subtropical forests with remarkable diversity of species and taxonomical challenges as a consequence of fig–pollinator coevolution. Ficus subsect. Frutescentiae includes about 30 species that are predominantly shrubs or small trees with Terminalia branching. Many of these species are difficult to delimit morphologically, and the group includes a tangle of uncertain taxa and incorrectly applied names. We conducted a phylogenetic analysis with internal and external transcribed spacer data (ITS and ETS) and data from 18 polymorphic microsatellite loci to evaluate the species status of the most perplexing members of this subsection. The results confirm the monophyly of subsect. Frutescentiae, with F. pedunculosa as sister to the rest. The F. erecta complex comprises approximately 17 taxa: F. erecta, F. abelii, F. boninsimae, F. nishimurae, F. iidaiana, F. gasparriniana var. laceratifolia, F. gasparriniana var. viridescens, F. pyriformis, F. stenophylla, F. fusuiensis, F. fengkaiensis, F. sinociliata, F. tannoensis, F. vaccinioides, F. formosana, F. pandurata, and F. periptera. The last five of these were supported as good species, while the others were not well supported by the present evidence. Evidence also supported the status of the non-F. erecta complex species including. F. pedunculosa, F. ischnopoda, F. heteromorpha, and F. variolosa. Ficus filicauda and F. neriifolia are possibly conspecific. The species status of F. potingensis should be restored and it should be treated as a member of section Eriosycea. Identification of the remaining taxa (F. gasparriniana var. esquirolii, F. ruyuanensis, F. daimingshanensis, F. chapaensis, F. changii, F. trivia, and F. tuphapensis) and their relationships to the F. erecta complex were not clarified. As a whole, only ten species in this subsection are confirmed, one is excluded, one is synonymous, and the others are either unresolved or short of samples. There appears to be a consistent genetic background among these unresolved groups, which suggests that repeated hybridization (as a result of pollinator host shifts) has filled up the interspecific gaps during the fig–pollinator coevolution process.     

Clinical relevance of infections with zoonotic and human oral species of <Emphasis Type="Italic">Campylobacter</Emphasis>

Genus Campylobacter has been recognized as a causative bacterial agent of animal and human diseases. Human Campylobacter infections have caused more concern. Campylobacters can be classified into two groups in terms of their original host: zoonotic and human oral species. The major zoonotic species are Campylobacter jejuni and Campylobacter coli, which mostly reside in the intestines of avian species and are transmitted to humans via consumption of contaminated poultry products, thus causing human gastroenteritis and other diseases as sequelae. The other campylobacters, human oral species, include C. concisus, C. showae, C. gracilis, C. ureolyticus, C. curvus, and C. rectus. These species are isolated from the oral cavity, natural colonization site, but have potential clinical relevance in the periodontal region to varying extent. Two species, C. jejuni and C. coli, are believed to be mainly associated with intestinal diseases, but recent studies suggested that oral Campylobacter species also play a significant role in intestinal diseases. This review offers an outline of the two Campylobacter groups (zoonotic and human oral), their virulence traits, and the associated illnesses including gastroenteritis.