SPECTROSCOPIC DETERMINATION OF THE AVERAGE NUMBER OF COAGGREGATES (Nco) OF CHOLESTERYL ESTERS AND THE FLUORESCENCE PROBE

Average aggregate number of coaggregates(N_co)of CE-n or BL-n and the fluoresc- ence probe(Np-16)have been determined by using time-resolved fluorescence spectroscopy. Chain-length,hydroxy-group and chain-foldability effects on the N_co have been discussed.

Characterization of Fusobacterium nucleatum ATCC 23726 adhesins involved in strain-specific attachment to Porphyromonas gingivalis

Bacterial adherence is an essential virulence factor in pathogenesis and infection. Fusobacterium nucleatum has a central role in oral biofilm architecture by acting as a bridge between early Gram-positive and late Gram-negative colonizers that do not otherwise adhere to each other. In this study, we survey a key adherence interaction of F. nucleatum with Porphyromonas gingivalis, and present evidence that multiple fusobacterial adhesins have a role in the attachment of F. nucleatum ATCC 23726 to P. gingivalis in a highly strain-dependent manner. Interaction between these species displayed varying sensitivities to arginine, galactose and lactose. Arginine was found to hamper coaggregation by at least 62% and up to 89% with several P. gingivalis strains and galactose inhibition ranged from no inhibition up to 58% with the same P. gingivalis strains. Lactose consistently inhibited F. nucleatum interaction with these P. gingivalis strains ranging from 40% to 56% decrease in coaggregation. Among the adhesins involved are the previously described Fap2 and surprisingly, RadD, which was described in an earlier study for its function in attachment of F. nucleatum to Gram-positive species. We also provide evidence for the presence of at least one additional adhesin that is sensitive to arginine but unlike Fap2 and RadD, is not a member of the autotransporter family type of fusobacterial large outer membrane proteins. The strain-specific binding profile of multiple fusobacterial adhesins to P. gingivalis highlights the heterogeneity and complexity of interspecies interactions in the oral cavity.

Analysis of interspecies adherence of oral bacteria using a membrane binding assay coupled with polymerase chain reaction-denaturing gradient gel electrophoresis profiling

Information on co-adherence of different oral bacterial species is important for understanding interspecies interactions within oral microbial community. Current knowledge on this topic is heavily based on pariwise coaggregation of known, cultivable species. In this study, we employed a membrane binding assay coupled with polymerase chain reaction-denaturing gradient gel electrophoresis （PCR-DGGE） to systematically analyze the co-adherence profiles of oral bacterial species, and achieved a more profound knowledge beyond pairwise coaggregation. Two oral bacterial species were selected to serve as ＂bait＂： Fusobacterium nucleatum （F. nucleatum） whose ability to adhere to a multitude of oral bacterial species has been extensively studied for pairwise interactions and Streptococcus mutans （S. mutans） whose interacting partners are largely unknown. To enable screening of interacting partner species within bacterial mixtures, cells of the ＂bait＂ oral bacterium were immobilized on nitrocellulose membranes which were washed and blocked to prevent unspecific binding. The ＂prey＂ bacterial mixtures （including known species or natural saliva samples） were added, unbound ceils were washed off after the incubation period and the remaining cells were eluted using 0.2 mol.L1 glycine. Genomic DNA was extraeted, subjeeted to 16S rRNA PCR amplification and separation of the resulting PCR produets by DGGE. Selected bands were recovered from the gel, sequenced and identified via Nucleotide BLAST searches against different databases. While few bacterial species bound to S. mutans, consistent with previous findings F.. nucleatum adhered to a variety of bacterial species including uncultivable and uneharacterized onesl This new approach can more effectively analyze the co-adherence profiles of oral bacteria, and could facilitate the systematic study of interbacterial binding of oral microbial species.

Deaggregation of long chain alkyl β-naphthoic acid ester with β-CD and α-CD:A mimic way to remove excessive fat from fatty liver

The deaggregating ability of β-CD and α-CD against the aggregated n-hexadecyl β-naphthoate （A16） and n-dodecyl β-naphthoate （A12） depended not only on the aggregating tendency of A16 and A12 but also on the initial concentration of the aggregated A16 or A12. The inclusive ability of β-CD with the substrates is greater than that of α-CD under hydrophobiclipophilic interaction.

ELECTROSTATICALLY STABILIZED AGGREGATE (ESAg) Ⅱ.EVIDENCE DERIVED FROM THE COAGGREGATING BEHAVIOR OF A CATIONIC KINETIC PROBE (P16^+) WITH SURFACTANTS

The coaggregating behavior of the cationic kinetic probe P16;with different types of surfactants are in complete agreement with predictions based on the newly proposed ESAg concept.

HYDROXY-GROUP EFFECT ON COAGGREGATION

The coaggregating tendencies of dodecane,hexadecane,dodecanol and hexadecanol have been investigated kinetically.It has been confirmed that organic molecules with a hydroxy-group possess smaller coaggregating tendencies than similar molecules without the hydroxy-group.

COAGGREGATION AND COAGGREGATION INHIBITION BETWEEN PERIO-PATHOGENIC AND CARIOGENIC BACTERIA

Objective To screen the coaggregating pairs between perio-pathogenic and cariogenic bacteria and to investigate the susceptibility of these coaggregations to inhibitors. Methods 4 strains of perio-pathogenic bacteria, Fusobacterium nuleatum （Fn） ATCC 10953, Actinobacilllus actinomycetem comitans （Aa） Y4, Porphyromonas gingivalis （Pg） ATCC 33277,Prevotella intermedia （Pi） ATCC 25261 and 4 strains of cariogenic bacteria, Streptococcus mutans （Sm） lngbritt, Streptococcus sanguis （Ss） 34, Actinomyces viscosus （ Av） 19246 and Lactobacillus acidophilus （La） ATCC 4356 were used to determine the coaggregating degrees of various combinations of the above bacteria by a visual assay and a turbidimetric assay. Then more than ＋ 2 （ or 20% ） coaggregation degrees＇ pairs were used to investigate the inhibitory effect of lactose and arginine and to identify the minimum of their coaggregation-inhibitory concentration. Results The coaggregation degrees of Fn-Av, Pg-Av, Fn-Sm, Fn-Ss, Fn-La and Pg-Ss pairs were higher than ＋ 2 （ 20% ）. 3.0 - 6.0mmol/L of arginine were considerably effective to the above pairs except Fn-Av pair and the disaggregation degrees were 49% - 92%. The maximum of their disaggregation degree to Fn-Av pair was just 18%. 120 - 300mmol/L of lactose were significantly effective to Pg-Ss pair, the disaggregation degrees were 57% - 91%. They partially inhibited Pg-Av pair and were almost ineffective to FnG^＋pairs. Conclusion The coaggregations between perio-pathogenic and cariogenic bacteria are highly specific. Most of them are relatively sensitive to arginine.

Is there a "chain-foldability" effect without neighboring moiety-assistance?

The coaggregating tendencies of five methyl esters of saturated or unsaturated single-chain carboxylic acids, namely octanoic (8-Me), dodecanoic (12-Me), stearic (18-Me), oleic (c18:1-Me) and elaidic (t-18:1-Me) acids, were investigated in five aquiorgano binary solvent systems, V/V DX-H2O (Phi=0.50, 0.45, 0.40, 0.30, 0.20), using naphthylethyl octyl (Np-8), dodecyl (Np-12), hexadecyl (Np-16) ether as fluorescent probes. The orders of their coaggregating tendencies changed in solvents of different Phi values. Our results could be rationalized by a chain-foldability effect without neighboring moiety participation.

Fluorescence study on the coaggregating tendencies of the cholesterols --the culprits of arteriosclerosis

The coaggregating tendencies of the culprits of arteriosclerosis, the cholesteryl esters (CE-n's), have been investigated in the 40:60 V/V (Φ= 0.40) dioxane (DX)-H2O system, by using decyl pyrenyl ketone (Py-11) as the fluorescence probe. The fluorescence intensity of Py-11 decreases when coaggregation occurs between CE-n and Py-11, because of the low polarity of the microenviroment of the coaggregates. The order of the coaggregating tendencies obtained from the fluorescence data is in full agreement with that from the kinetic method, i.e., CE-ol, CE-in > CE-12 > CE-8 > CE-18 > CE-0.

Neuroprotective Nanoscavenger Induces Coaggregation of β-Amyloid and Facilitates Its Clearance in Alzheimer’s Disease Brain

The accumulation of solubleβ-amyloid aggregates(sAβs)is one of the main culprits in Alzheimer’s disease(AD)progression,which can lead to synaptic dysfunction and subsequent neurodegeneration.Herein,we describe a nanoscavenger with novel structure that can cross the blood–brain barrier(BBB),accurately collect neurotoxic sAβs,and facilitate amounts ofβ-amyloid(Aβ)clearance.

Communication Chain-foldability effect on coaggregation Evidence derived from time-resolved fluorescence spectroscopy

Very recently,we have proposed that all culprit molecules of arteriosclerosis mightpossess a common and measurable inherent property,namely,a coaggregating ten-dency.Extensive kinetic measurements of these tendencies in terms of △CAgC valueshave led to a new and surprising observation,i.e.,the cholesteryl ester with a longsaturated 18-carbon chain(CE-18)actually has a much smaller tendency towardcoaggregation than that of the ester with a“short”8-carbon chain(CE-8).Thisstate of affairs has been coined as the“chain-foldability effect”,i.e.,the 18-carbon

Electrostatically stabilized aggregate(ESAg)——Ⅲ.Evidence derived from the coaggregating behavior of fluorescence probes(FP)with ionic surfactants

Hydr hobie一lipophilic interactions(HLI)will start to bri about the formationof simple aggregates(Ag,s)and eoa egates(CoAg,s)from neutral organie moleeuleswhich possess at least onefl ble chain with more than seven eHZ grou ,1,2 at theeritieala egate eoncentration