An algal enzyme required for biosynthesis of the most abundant marine carotenoids.

Fucoxanthin and its derivatives are the main light-harvesting pigments in the photosynthetic apparatus of many chromalveolate algae and represent the most abundant carotenoids in the world's oceans, thus being major facilitators of marine primary production. A central step in fucoxanthin biosynthesis that has been elusive so far is the conversion of violaxanthin to neoxanthin. Here, we show that in chromalveolates, this reaction is catalyzed by violaxanthin de-epoxidase-like (VDL) proteins and that VDL is also involved in the formation of other light-harvesting carotenoids such as peridinin or vaucheriaxanthin. VDL is closely related to the photoprotective enzyme violaxanthin de-epoxidase that operates in plants and most algae, revealing that in major phyla of marine algae, an ancient gene duplication triggered the evolution of carotenoid functions beyond photoprotection toward light harvesting.

Factors associated with anterior cruciate ligament injury: history in female athletes.

AIM: Little is known about the association of lower extremity structural malalignments, flexibility patterns, generalized laxity, postural control, previous ankle sprain history and the increased risk of anterior cruciate ligament (ACL) injuries in females. We hypothesized that females with a history of ACL injury would be more likely to have a history of prior ankle sprain and different structural alignments than females without a history of ACL injury. METHODS: It is a case control study: 33 young adult females with a history of an ACL injury and 33 controls with no history of knee injury provided their knee and ankle injury history and had 16 lower extremity measures taken. RESULTS: The factors most associated with ACL injury history were greater generalized laxity (r(2) change: 0.073), greater genu recurvatum (r(2) change: 0.069), and decreased iliotibial band (ITB) flexibility (r(2) change: 0.069). There was also a significant association between ACL injury history and previous ankle sprain injury history (chi squared=5.27; P=0.02). Those with a history of ACL injury were more likely to have had a prior ipsilateral ankle sprain. CONCLUSION: Increased generalized laxity, greater genu recurvatum, and decreased ITB flexibility discriminated between females with and without history of ACL injury. A relationship linking previous ankle injury and ACL injury risk was found. Taking a thorough medical history and screening for generalized laxity, genu recurvatum, and a tight ITB in those with a history of LAS, may help identify those at risk for an ACL injury and who may benefit most from preventive measures.

Effect of divalent ions on the activity of cancer procoagulant.

The effect of calcium (Ca2+), magnesium (Mg2+), manganese (Mn2+), iron (Fe2+), and zinc (Zn2+) on the factor X-activating activity of cancer procoagulant (CP) was studied. Activity of CP was evaluated with a three-stage chromogenic assay (liquid-phase assay, "native" CP) and with an immunocapture enzyme (ICE) assay (solid-phase assay, immobilized CP). In the liquid-phase assay, CP activity was Ca(2+)-dependent, and Mg2+ (5 mM) or Mn2+ (0.01-0.1 mM) could substitute for Ca2+. There was no additive effect of Mg2+ and Ca2+ on the activity of CP. Activity of CP in the liquid-phase assay, in the presence of 7 mM Ca2+, was enhanced by 0.1 mM Mn2+ to about 240% of the activity observed when only Ca2+ was present in the reaction. Zn2+ and Fe2+ did not activate CP in the absence of Ca2+; they inhibited CP activity in a concentration-dependent mode when administered in the presence of Ca2+. The activity of CP evaluated by the solid-phase assay (ICE assay) was neither Ca(2+)-dependent nor was it susceptible to potentiation by Mn2+ administered after CP was bound to IgM. CP exposed to 5 mM Mn2+ before binding to IgM expressed about 85% higher activity than without the presence of Mn2+. When CP was first preincubated with divalent ion and then immunocaptured, the signal generated in the enzyme-linked immunoadsorbent assay by Mn(2+)-containing CP was significantly different (30% greater) than signals generated by CP without Mn2+ or containing different ion. These data suggest that: (1) there is a significant conformational change of the CP molecule that takes place after capturing CP by the monoclonal IgM antibody on the solid surface; (2) the divalent ions are not directly involved in enzyme-substrate interactions in the CP moiety; and (3) the interaction of Mn2+ with CP seems to be different from that of the other divalent ions.

Application of cancer procoagulant as an early detection tumor marker.

BACKGROUND: In spite of many advances in the analytical reagents (antibodies), analytical systems, and the clinical application of tumor markers, the present markers do not detect early stage cancer. Preliminary data with an antigen specific to tumor tissue, cancer procoagulant (CP), suggest its possible role in the detection of early stage cancer. This study was aimed at determining the clinical use of CP as an early stage tumor marker. METHODS: An improved enzyme-linked immunosorbent assay (ELISA) was developed to measure CP concentration in serum. A panel of 817 blinded serum samples were examined from three groups of people: 573 cancer, 106 benign, and 139 normal. RESULTS: The sensitivity of all samples analyzed from cancer patients was 80%. The CP ELISA was able to detect ovarian, colon, and kidney cancer at a sensitivity greater than 85%; breast, prostate and small cell lung cancer was detected at a sensitivity of 80-85%. Particularly interesting was the observation that early stage cancers, regardless of site, were detected effectively. In some groups, the CP assay correctly identified 100% of the patients with stage I and II cancer. The assay was able to identify correctly noncancer patient sera at a specificity of 83% for those with benign disease and 82% for the normal individuals. CONCLUSIONS: The CP assay has potential as an aid in diagnosing early stage malignancies and thereby may significantly improve the survival rate of cancer patients.