Seasonal variations in fouling diatom communities on the Yantai coast

Fouling diatoms are a main component of biofilm,and play an important role in marine biofouling formation. We investigated seasonal variations in fouling diatom communities that developed on glass slides immersed in seawater,on the Yantai coast,northern Yellow Sea,China,using microscopy and molecular techniques. Studies were conducted during 2012 and 2013 over 3,7,14,and 21 days in each season. The abundance of attached diatoms and extracellular polymeric substances increased with exposure time of the slides to seawater. The lowest diatom density appeared in winter and the highest species richness and diversity were found in summer and autumn. Seasonal variation was observed in the structure of fouling diatom communities. Pennate diatoms Cylindrotheca,Nitzschia,Navicula,Amphora,Gomphonema,and Licmophora were the main fouling groups. Cylindrotheca sp. dominated in the spring. Under laboratory culture conditions,we found that Cylindrotheca grew very fast,which might account for the highest density of this diatom in spring. The lower densities in summer and autumn might result from the emergence of fouling animals and environmental factors. The Cylindrotheca sp. was identified as Cylindrotheca closterium using18 S rDNA sequencing. The colonization process of fouling diatoms and significant seasonal variation in this study depended on environmental and biological factors. Understanding the basis of fouling diatoms is essential and important for developing new antifouling techniques.

Microbial Biofilm Formation as a Dental-fouling Microorganisms Attachment Phenomenon in Oral Cavity Environment

DMFP （Dental microbial fouling phenomenon） of OCE （oral cavity environment） was studied in the local dental labs. Multi-smears of mature supra gingival plaques were randomly collected from fifty persons in dental labs that had different cultures, ages, sex and different scientific levels. Rapid microbial identification method was used to identify of these multi-smears by using vitek-2 compact instrument. The most frequent and appearance species of bacteria was Pantoeae spp., then Klebsiella pneumonia. Total species of microbial fouling in supra gingival plaques were included sixteen species： Staphyllococcus aureus, Klebsiella pneumonia, Pantoeae spp., Aercococcus viridians, Leuconostoc mesenteroides cremorise, Granuli.adiacens, Streptococcus sanguinis, Staphyllococcus sciuri, Stenotrophomonus maltiphilia, Kocuria varians, Gememlla morbillorum, Granulicatella adiacens, Nonreac biopattern, Kocuria kritinae, Kocuria rosea and Nonreac.biopattern while six fungal species were Tricoderma viride, Aspergillus flavus, Tricoderma harzianum, Cladosporium macrocarpum, Penicillium citrinum and Verticillium lecanii in addition to two yeast species were recorded Candida dubliniensis and Candida glabrata. The results were detected the most appearance of bacteria Pantoeae sp., then Klebsiella pneumonia, then Staphyllococcus aureus. These results of study suggest that adhesive strength conjugated with the biofilm layers presence in OCE may vary across different from one to other persons and mark a new path of inquiry for dental Microbial-fouling phenomenon research.