Cross-Kingdom Cell-to-Cell Interactions in Cariogenic Biofilm Initiation

Candida albicans is known to form polymicrobial biofilms with various Streptococcus spp., including mitis and mutans group streptococci. Streptococcus gordonii (mitis group) has been shown to bind avidly to C. albicans hyphae via direct cell-to-cell interaction, while the cariogenic pathogen Streptococcus mutans (mutans group) interacts with the fungal cells via extracellular glucans. However, the biophysical properties of these cross-kingdom interactions at the single-cell level during the early stage of biofilm formation remain understudied. Here, we examined the binding forces between S. mutans (or S. gordonii) and C. albicans in the presence and absence of in situ glucans on the fungal surface using single-cell atomic force microscopy and their influence on biofilm initiation and subsequent development under cariogenic conditions. The data show that S. gordonii binding force to the C. albicans surface is significantly higher than that of S. mutans to the fungal surface (~2-fold). However, S. mutans binding forces are dramatically enhanced when the C. albicans cell surface is locally coated with extracellular glucans (~6-fold vs. uncoated C. albicans), which vastly exceeds the forces between S. gordonii and C. albicans. The enhanced binding affinity of S. mutans to glucan-coated C. albicans resulted in a larger structure during early biofilm initiation compared to S. gordonii–C. albicans biofilms. Ultimately, this resulted in S. mutans dominance composition in the 3-species biofilm model under cariogenic conditions. This study provides a novel biophysical aspect of Candida-streptococcal interaction whereby extracellular glucans may selectively favor S. mutans binding interactions with C. albicans during cariogenic biofilm development.

ESTABLISHING OF AQUATIC PROTECTED AREAS (APAS) NETWORK IN PAPUA'S BIRD HEAD'S SEASCAPE (BHS): SPECIES MIGRATION AND GENETIC CONNECTIVITY

In general, the APAs network serves to protect, conserve and utilize marine resources in order to ensure sustainability is guaranteed on an ongoing basis. The APAs network is a network involving the management of two or more APAs (Kaimana, Fakfak, Bintuni, Raja Ampat, Sorong, Tambrauw and Teluk Wondama) synergistically linked to biophysical, species migration and genetic connectivity. From the biophysical aspect, BHS is characterized by migration and the specific habitat of endangered charismatic species and genetic connectivity. Migration in the BHS region can be seen from the migration of turtles, sharks, sharks, manta rays and cetaceans (whales and dolphins). The endangered species are unique in BHS and they utilize BHS area as a migration path and as an aggregation area. The world's largest leatherback turtle nesting beaches are also found in BHS, including other species of turtle nesting, such as green turtle, olive ridley turtle, and hawksbill turtle. Other charismatic species often found in the BHS region are manta rays, whale sharks, dugongs, and other endemic fish species. The BHS region is a cetacean hotspot that supports populations of species protected by the IUCN Red List. Of the 30 species of cetaceans recorded in Indonesia, 15 species are found in BHS. The whales can also migrate from Cenderawasih Bay to Raja Ampat Waters. Manta rays are often found in Raja Ampat, Yapen Island, and Cenderawasih Bay. Good collaboration is required in protecting species and understanding oceanographic phenomena that relate to the migration and genetic connectivity of the organism. Keywords Conservation network, bio-physical aspect, species migration, genetic connectivity, Bird's Head Seascape

Biofilm Cohesive Strength as a Basis for Biofilm Recalcitrance: Are Bacterial Biofilms Overdesigned?

Bacterial biofilms are highly resistant to common antibacterial treatments, and several physiological explanations have been offered to explain the recalcitrant nature of bacterial biofilms. Herein, a biophysical aspect of biofilm recalcitrance is being reported on. While engineering structures are often overdesigned with a factor of safety (FOS) usually under 10, experimental measurements of biofilm cohesive strength suggest that the FOS is on the order of thousands. In other words, bacterial biofilms appear to be designed to withstand extreme forces rather than typical or average loads. In scenarios requiring the removal or control of unwanted biofilms, this emphasizes the importance of considering strategies for structurally weakening the biofilms in conjunction with bacterial inactivation.

Detection Of Hypercoagulable State By Measuring Mechanical Impedance Of Clotting Whole Blood

The transition of mechanical impedance of clotting whole blood was determined by Sonoclot(Scienco Inc. U.S.A.) in 22 normal individuals, 14 patients with arterial thrombosis and 20 patients with venous thrombosis. Sonoclot primarily senses loss modulus and records entire coagulation process continuously. Peak g represents the maximum mechanical impedance of clot and slope i represents the rate of gelling process. Sixty-five per cent of cases with venous thrombosis and 36 % of cases with arterial thrombosis showed abnormally high values either in g or in i. In venous thrombosis, there were positive correlations between hematocrit and i, and between fibrinogen and g (r=0.6, p<0.01)In arterial thrombosis, there were positive correlations between platelet count and g (r=0.6, p<0.05) and negative correlations between fibrinogen and g and also between fibrinogen and i (r=-0.6, p<0.05). In normal individuals, no significant correlations were noted between any two of these parameters.Our results suggest that analysis of clotting process from the biophysical aspect is important to demonstrate hypercoagulable state and that mechanical impedance can be a common indicator of hypercoagulable state.