In 1972, Carijoa riisei, a shallow-water azooxanthellate octocoral, was discovered invading the fouling community in Pearl Harbor. Invasive populations of C. riisei are now so dominant that they are considered a grave threat to Hawaii's native reef ecosystems and economy. C. riisei's juvenile and reproductive biology is not very well understood because of the difficulty of field observations at the depth that C. riisei inhabits. A laboratory based culture technique would represent a significant advancement in our ability to investigate questions involving the spread and control of C. riisei. Flow-through aquariums were set-up to house captive C. riiseicolonies over a period of seven weeks. C. riisei colonies were successfully grown on freeze-dried copepods and exhibited release of gametes. The success of this culturing method bodes well for long-term maintenance of C. riisei and further experiments with C. riiseibiology.
Staphylococcus aureus is an opportunistic human pathogen that is found in a large percentage of the population and passively colonizes primarily in the skin or in the nares. It is also occasionally found in high abundance in coastal recreational waters due to shedding from swimmers and other beachgoers. As a result, coastal swimming areas are a potential source of community-acquired S. aureus infections. The capacity of a given S. aureus strain to cause infection varies among strains and is determined by the presence or absence of a large number of virulence-associated genes, some of which are encoded by prophages. In order to determine the abundance and characterize the diversity of S. aureus strains to which swimmers in coastal waters of Oahu may be exposed, 30 isolates were collected from seawater at Kuhio Beach in Waikiki, HI and screened for the presence or absence of phage-type specific DNA segments using polymerase chain reaction. One to five prophage segments were detected per isolate with no prophage-free strain found. Prophage segments from ø3A-like and ø77-like phages were most common, showing up in nearly all isolates collected. Data from this study suggests that prophage content in S. aureusisolates varies widely among strains and the diversity at Kuhio Beach is relatively high.
Studies have shown that the use of copepod nauplii as a first feed will increase the survival rate of larvae of several ornamental finfish species, and it is widely agreed that the use of copepod nauplii as a first feed will increase the number of ornamental species which can be successfully cultivated. Many bioreactors have focused on producing live nauplii, but problems arise because the nauplii grow too quickly. To circumvent this problem, we propose a novel airlift bioreactor design to support the collection and preservation of copepod eggs. In most cases, airlift columns are used in bioremediation to suspend pellets for the growth of biofilm. In this case, airlift columns are used to both aerate and to separate copepod eggs from adults into a collection chamber.
Mycoplasma arthritidis-derived Mitogen (MAM) is a superantigen that can dimerize major histocompatibility complex (MHC) antigen, HLA-DR1 molecule. MAM is known to induce chronic arthritis in rodents which bear a resemblance to human rheumatoid arthritis. MAM stimulates T-cell activation by interacting with class II MHC including HLA-DR1, which is one of the important disease risk genes in rheumatoid arthritis. It has been suspected that MAM a plays role in human rheumatoid arthritis. The high affinity of MAM to the peptide/MHC complex is due to interaction between the N-terminal domain of MAM and the antigen-presenting domain of MHC. In this study, we created mutants at the N-terminal domain of MAM to investigate the MAM residues responsible for this interaction. We mutated four amino acids: threonine, arginine, lysine and glutamine at positions 89, 91, 92, and 99, respectively. The four residues, which are at the MAM-MHC interface, were individually converted to alanine. Sedimentation velocity of analytical ultracentrifuge was used to identify the heterogeneous interaction between the mutant and the MHC molecule. The dissociation constants (KD) of the mutant MAM-MHC complexes were measured using sedimentation equilibrium. Of the four mutants, R91A binds to HLA DR1 with the lowest affinity, which is about twenty times lower than that of the wild-type. Other mutants reduce the binding affinity of MAM to HLA DR1 by 7-10 folds. These data provide evidence that substitution of any of these four residues will cause the affinity of MAM to the peptide/HLA-DR1 complex to decrease.