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Mass mortality of the dominant coral reef herbivore Diadema antillarumin the Caribbean in the early 1980s contributed to a persistent phase shift from coral- to algal-dominated reefs. In 2022, a scuticociliate most closely related to Philaster apodigitiformiscaused further mass mortality of D. antillarumacross the Caribbean, leading to >95% mortality at affected sites. Mortality was also reported in the related species Diadema setosumin the Mediterranean in 2022, though the causative agent of the Mediterranean outbreak has not yet been determined. In April 2023, mass mortality of Diadema setosumoccurred along the Sultanate of Oman's coastline. Urchins displayed signs compatible with scuticociliatosis including abnormal behavior, drooping and loss of spines, followed by tissue necrosis and death. Here we report the detection of an 18S rRNA gene sequence in abnormal urchins from Muscat, Oman, that is identical to the Philasterstrain responsible for D. antillarummass mortality in the Caribbean. We also show that scuticociliatosis signs can be elicited in Diadema setosumby experimental challenge with the cultivated Philasterstrain associated with Caribbean scuticociliatosis. These results demonstrate the Philastersp. associated with D. antillarummass mortality has rapidly spread to geographically distant coral reefs, compelling global-scale awareness and monitoring for this devastating condition through field surveys, microscopy, and molecular microbiological approaches, and prompting investigation of long-range transmission mechanisms.

Potent Antiemetic Effects of the New Serotonin Antagonists PATIENTS CONSISTENTLY rank chemotherapy-induced emesis first among the adverse effects associated with oncologic treatment. Two thirds of the more than 30 effective [...]

Caldesmon is an inhibitory protein believed to be involved in the regulation of thin filament activity in smooth muscles and is a major cytoplasmic substrate for MAP kinase. NMR spectroscopy shows that the actin binding properties of the minimal inhibitory region of caldesmon, residues 750-779, alter upon MAP kinase phosphorylation of Ser-759, a residue not involved in actin binding. This phosphorylation leads to markedly diminished actin affinity as a result of the loss of interaction at one of the two sites that bind to F-actin. The structural basis for the altered interaction is identified from the observation that phosphorylation destabilises a turn segment linking the two actin binding sites and thereby results in the randomisation of their relative disposition. This modulatory influence of Ser-759 phosphorylation is not merely a function of the bulkiness of the covalent modification since the stability of the turn region is observed to be sensitive to the ionisation state of the phosphate group. The data are discussed in the context of the inhibitory association of the C-terminal domain of caldesmon with F-actin.

Phospholamban regulates the activity of the calcium-activated ATPase (CaATPase) of cardiac sarcoplasmic reticulum. Equilibrium fluorescence studies have shown that the N-terminal cytoplasmic region of phospholamban (residues 1–20, domain 1) causes a decrease in the intrinsic tryptophan fluorescence of the CaATPase. The interaction of phospholamban residues 1–20 with the CaATPase also results in spectral changes for the extrinsic chromophore FITC covalently attached to the cytoplasmic region of the calcium pump. The fluorescence changes for both reporter groups correlate with a dissociation constant of ≈ 40µM for the complex between phospholamban residues 1–20 and the CaATPase. Complex formation is notably weaker when phospholamban 1–20 is titrated into the CaATPase in the presence of calcium, with altered conformational effects resulting from binding. The interaction of domain 1 of phospholamban with the CaATPase is also reduced upon phosphorylation of phospholamban 1–20 at Ser-16. This region of phospholamban 1–20 is shown by isotope-edited NMR study to be involved in interaction with the CaATPase. Binding of the phosphorylated peptide is not abolished, however, indicating that phospholamban 1–20 remains associated with the CaATPase even after phosphorylation. The data provide direct evidence for the interaction between the cytoplasmic regions of phospholamban and the pump, and are discussed in the context of the mechanism for inhibition of cardiac CaATPase activity by phospholamban.

The fundamental clinical, viral, and immunologic features of early-stage human immunodeficiency virus type 1 (HIV-1) disease were examined in a seroprevalent cohort of 28 men and 14 women assessed longitudinally at three equally dispersed time points over a mean of 43 months. There were no gender differences in the relative risk of developing AIDS-defining end points or death. The median serum RNA levels assessed at the three study time points were 3.3-, 4.9-, and 1.5-fold lower, respectively, in women than in men. This suggests that while serum virus load may be as powerful a correlate of disease status in women as it is in men, the absolute values of the virus levels may be different in the 2 populations. These observations may have implications for the interpretation of levels of virus burden in women for the assessment of disease progression, transmission, and treatment.