Search for: All records

The molecular interactions of sulfated glycans, such as heparin, with antithrombin (AT) and platelet factor 4 (PF4) are essential for certain biological events such as anticoagulation and heparin induced thrombocytopenia (HIT). In this study, a library including 84 sulfated glycans (polymers and oligomers) extracted from marine algae along with several animal-originated polysaccharides were subjected to a structure-activity relationship (SAR) study regarding their specific molecular interactions with AT and PF4 using surface plasmon resonance. In this SAR study, multiple characteristics were considered including different algal species, different methods of extraction, molecular weight, monosaccharide composition, sulfate content and pattern and branching vs. linear chains. These factors were found to influence the binding affinity of the studied glycans with AT. Many polysaccharides showed stronger binding than the low molecular weight heparin (e.g., enoxaparin). Fourteen polysaccharides with strong AT-binding affinities were selected to further investigate their binding affinity with PF4. Eleven of these polysaccharides showed strong binding to PF4. It was observed that the types of monosaccharides, molecular weight and branching are not very essential particularly when these polysaccharides are oversulfated. The sulfation levels and sulfation patterns are, on the other hand, the primary contribution to strong AT and PF4 interaction. 

Ciliates are abundant microplankton that are widely distributed in the ocean. In this paper, the distribution patterns of ciliate diversity in the South China Sea (SCS) were analyzed by compiling community data from previous publications. Based on morphological identification, a total of 592 ciliate species have been recorded in the SCS. The ciliate communities in intertidal, neritic and oceanic water areas were compared in terms of taxonomy, motility and feeding habit composition, respectively. Significant community variation was revealed among the three areas, but the difference between the intertidal area and the other two areas was more significant than that between neritic and oceanic areas. The distributions of ciliates within each of the three areas were also analyzed. In the intertidal water, the community was not significantly different among sites but did differ among habitat types. In neritic and oceanic areas, the spatial variation of communities among different sites was clearly observed. Comparison of communities by taxonomic and ecological traits (motility and feeding habit) indicated that these traits similarly revealed the geographical pattern of ciliates on a large scale in the SCS, but to distinguish the community variation on a local scale, taxonomic traits has higher resolution than ecological traits. In addition, we assessed the relative influences of environmental and spatial factors on assembly of ciliate communities in the SCS and found that environmental selection is the major process structuring the taxonomic composition in intertidal water, while spatial processes played significant roles in influencing the taxonomic composition in neritic and oceanic water. Among ecological traits, environmental selection had the most important impact on distributions. 

Previously compound12showed great anti‐trypanosome activity without toxicity in anin vivostudy. In the current study, a sensitive and rapid high‐performance liquid chromatography–tandem mass spectrometry (HPLC–MS/MS) method was developed and validated to investigate its pharmacokinetics in mouse plasma. A protein precipitation method was applied to extract the compound, and it was then separated using a Kinetex C₁₈column with mobile phase consisting of acetonitrile–0.1% formic acid water (50:50, v/v) at a flow rate of 300 μl/min. The analytes were detected with the multiple reaction monitoring in negative electrospray ionization source for quantitative response of the compounds. Compound12was detected atm/z477.0 → 367.2, while the internal standard compound14was detected atm/z499.2 → 268.2. Inter‐ and intra‐day precision was <5.22 and 2.79% respectively, while the accuracy range was within ±9.65%. The method was successfully applied to evaluate the pharmacokinetics of compound12in mouse plasma with two formulations (20% Cremophor EL or sesame oil) and drug administration routes (oral and intraperitoneal injection). We observed a better drug serum concentration with the Cremophor formulation, and the two different drug administration routes did not show significant differences from the drug distribution.

 

The relative importance of different ecological processes that shape community structure is a central but poorly understood topic in protist ecology. This study used an 18S rRNA gene sequencing approach to examine the relative contributions of environmental selective (environmental filtering) and neutral processes (dispersal and ecological drift) in the community assembly of three diverse protist groups (Bacillariophyta, Cercozoa, and Ciliophora) from intertidal sediment samples spanning a geographical distance up to 12,000 km. All three protist communities exhibited similar and distinct biogeographical patterns, and followed strong distance–decay relationships at continental scale (ca. 12,000 km), regional scale (ca. 1500 km), and local scale (ca. 50 km). Network analysis showed that temperature, salinity, nitrite and nitrate nitrogen, total nitrogen, and 0.1–0.25 mm grain size together associated with 60.8%, 55.5%, and 50.0% of the OTUs, which represented 68.1%, 58.5%, and 59.2% of sequence abundances for Bacillariophyta, Cercozoa, and Ciliophora co‐occurrence networks, respectively, indicating that these environmental variables played the central roles in influencing community composition. On the other hand, a neutral community model explained 73.6%, 64.2%, and 70.2% of community variation for Bacillariophyta, Cercozoa, and Ciliophora, respectively. More importantly, variation partitioning and partial Mantel tests showed that environmental selection exhibited a slightly greater influence on Ciliophora compared to spatial factors, but both components were roughly equivalent in Bacillariophyta and Cercozoa communities. Taken together, these results demonstrate that both environmental selection and neutral processes play important roles in creating the biogeographical patterns of protist communities in intertidal sandy beach ecosystems.