Smooth muscle myosin phosphorylated at single head shows sustained mechanical activity

Smooth muscle contraction is regulated by the phosphorylation of myosin. It is well known that tonic smooth muscles can maintain force with low energy consumption (latch state); however, the molecular mechanism underlying this phenomenon is unresolved. Here we show that single-head phosphorylated smooth myosin (SHPMII) exhibits fast ( approximately 24 s(-1)) and slow prolonged ( approximately 1 s(-1)) actin interactions, whereas double-head phosphorylated myosin (DHPMII) predominantly exhibits the fast ( approximately 29 s(-1)) interaction, suggesting that the phosphorylated head of SHPMII is mechanically as active as that of DHPMII. Both the fast and the slow actin interactions of SHPMII support the positive net mechanical displacement of actin. The actin translocating velocity of SHPMII was much slower than that of DHPMII, which is consistent with the slow actin interaction of SHPMII. We propose that the "latch state" can be explained by the motor characteristics of SHPMII that is present during the sustained phase of contraction.     

Structures and populations of conformers of nucleoside monophosphates in aqueous solution. I. General methods of conformation search with lanthanide-ion probes and spin-coupling constants and application to uridine-5′-monophosphate

The Ln(III)-induced shifts and Gd(III)-induced changes of the spin-lattice relaxation times were observed for the ¹H and ¹³C resonances of uridine-5′-monophosphate (5′-UMP) in ²H₂O solutions at pH 1.7–2.0. The vicinal spin-coupling constants changed little by the addition of lanthanide cations, indicating that the conformations of this mononucleotide remained almost the same upon complex formation. A general method was worked out for conformation studies of flexible molecules with lanthanide-ion probes and spin-coupling constants. This method was applied in an extensive computer search for 5′-UMP, and it was concluded that the observed Ln(III)-induced shifts, Gd(III)-induced changes of relaxation times, and vicinal spin-coupling constants could only be accounted for by a mixture of conformers. The populations of the major conformers, gg-3′-endo-anti, and gg-2′-endo-anti, amount to 46 ± 12% and 29 ± 11%, respectively. The correlation between local conformations are discussed on the basis of the present results.     

New type of delayed light emission from photosynthetic bacteria

A new type of short-wavelength delayed light emission from the photosynthetic bacteria Rhodospirillum rubrum and Rhodopseudomonas spheroides was found. The emission and action spectra suggest that magnesium protoporphyrin IX or a similar compound is the emitter. Anaerobic conditions were necessary to detect this long-lived emission. Some inhibitors of the primary processes of photosynthesis affected the intensity and the decay rate of the delayed light emission.     

TRANSFUSIONS—Hazardous Acid-Base Changes with Citrated Blood

In a study of the acid-base changes in the blood of rabbits during and following transfusions of citrated blood and of heparinized blood, it was observed that, with citrated blood, pH decreased and carbon dioxide tensions rose. With heparinized blood, the acid-base balance was maintained within normal limits following transfusions.The potential hazards of rapid massive citrated blood transfusions in the anesthetized patient during operation must be kept in mind.     

Tau Phosphorylation and Cleavage in Ethanol-Induced Neurodegeneration in the Developing Mouse Brain

Previous studies indicated that ethanol-induced neurodegeneration in postnatal day 7 (P7) mice, widely used as a model for the fetal alcohol spectrum disorders, was accompanied by glycogen synthase kinase-3β (GSK-3β) and caspase-3 activation. Presently, we examined whether tau, a microtubule associated protein, is modified by GSK-3β and caspase-3 in ethanol-treated P7 mouse forebrains. We found that ethanol increased phosphorylated tau recognized by the paired helical filament (PHF)-1 antibody and by the antibody against tau phosphorylated at Ser199. Ethanol also generated tau fragments recognized by an antibody against caspase-cleaved tau (C-tau). C-tau was localized in neurons bearing activated caspase-3 and fragmented nuclei. Over time, cell debris and degenerated projections containing C-tau appeared to be engulfed by activated microglia. A caspase-3 inhibitor partially blocked C-tau formation. Lithium, a GSK-3β inhibitor, blocked ethanol-induced caspase-3 activation, phosphorylated tau elevation, C-tau formation, and microglial activation. These results indicate that tau is phosphorylated by GSK-3β and cleaved by caspase-3 during ethanol-induced neurodegeneration in the developing brain.     

Reconsideration of the taxonomy of ellipsoidal species of Chlorella (Trebouxiophyceae, Chlorophyta), with establishment of Watanabea sen. nov.

Subcultures of SAG 211–9b and 1AM C-211, ultimately derived from CCAP 211/9b, a strain isolated by Pringsheim in 1939 and identified as Chlorella sac-charophila (Kruger) Migula were observed using light and electron microscopy. Their morphology proved to be basically identical. Both have two forms of cells, one (E-form) narrowly to broadly ellipsoidal, the other (S-form) ovoid to spheroidal. The cell wall of both forms is composed of a single smooth layer. The chloroplast of young cells is trough-like or saucer-shaped with a smooth margin, while that of mature cells is band- or cup-shaped with deep incisions. The thylakoid lamellae are loosely stacked and neither form has a pyrenoid. Both types of cells are capable of producing autospores: eight to 16 in E-form cells, two to four in S-form cells. These morphological features are different from those of C. saccharophila, which has a pyrenoid and produces only one form of autospores. In the absence of any existing genus that includes Chlorella-like algae with a simple cell wall, no pyrenoid, and two forms of mature cells and autospores, a new genus, Watanabea, is proposed with the type species W. reniformis.     

An Evaluation of Serodiagnostic Tests in Patients with Candidemia: Beta-Glucan,Mannan, Candida Antigen by Cand-Tec and D-Arabinitol

The serodiagnostic tests, beta-glucan, mannan, candida antigen by Cand-Tec, and D -arabinitol were evaluated in 10 patients with candidemia, 14 patients with suspected fungemia, and 10 healthy persons. By blood culture or lysis centrifugation, C. albicans was isolated from 5 patients, C. parapsilosis from 4, and C. tropicalis from 1 patient; no organisms were isolated from the 14 patients with suspected fungemia or the 10 healthy subjects. Beta-glucan was measured by the difference between two chromogenic limulus tests (Endotoxin test-D® and Endospecy®), which was more than 60 pg/ml in 7 of 9 (78%) candidemic patients and 1 of 12 (8%) patients with suspected fungemia. Mannan was positive in 6 of 10 (60%) candidemic patients and 1 of 13 (8%) patients with suspected fungemia. Both antigens were very sensitive and highly specific for candidemia. However, the Cand-Tec assay was less specific, because titers of more than 4 were observed in 5 of 14 (34%) patients with suspected fungemia. D -Arabinitol was the least sensitive, because a D -arabinitol/creatinine ratio greater than 2.0 μmol/mg was observed in only 2 of 7 (29%) candidemic patients. The titers of serodiagnostic tests decreased after successful treatment with an anti-fungal agent. Our results show that the combined use of the assays in necessary for accurate serological diagnosis of candidemia.