The MtrAB two-component system controls antibiotic production in Streptomyces coelicolor A3(2).

MtrAB is a highly conserved two-component system implicated in the regulation of cell division in the Actinobacteria. It coordinates DNA replication with cell division in the unicellular Mycobacterium tuberculosis and links antibiotic production to sporulation in the filamentous Streptomyces venezuelae. Chloramphenicol biosynthesis is directly regulated by MtrA in S.

NsrR from Streptomyces coelicolor is a nitric oxide-sensing [4Fe-4S] cluster protein with a specialized regulatory function.

The Rrf2 family transcription factor NsrR controls expression of genes in a wide range of bacteria in response to nitric oxide (NO). The precise form of the NO-sensing module of NsrR is the subject of controversy because NsrR proteins containing either [2Fe-2S] or [4Fe-4S] clusters have been observed previously. Optical, Mössbauer, resonance Raman spectroscopies and native mass spectrometry demonstrate that Streptomyces coelicolor NsrR (ScNsrR), previously reported to contain a [2Fe-2S] cluster, can be isolated containing a [4Fe-4S] cluster.

The synthesis of (-)-isodomoic acid C.

The neuroactive algal metabolite (-)-isodomoic acid C, a kainoid amino acid, has been synthesized for the first time. Asymmetric dearomatizing cyclization of an aromatic amide using a chiral lithium amide base generates a bicyclic enone containing a pyrrolidinone ring with the relative and absolute stereochemistry of the target. A further 15 synthetic steps, including conjugate cuprate addition to the enone of a side chain precursor, a Ru-promoted oxidation of the phenyl ring to the C2-carboxylic acid substituent, a regioselective Baeyer-Villiger reaction, and an E-selective Horner-Wadsworth-Emmons reaction, elaborate the cyclization product into the target molecule.

Treatment outcomes in depression: comparison of remote treatment through telepsychiatry to in-person treatment.

Objective: Telepsychiatry is an increasingly common method of providing psychiatric care, but randomized trials of telepsychiatric treatment compared to in-person treatment have not been done. The primary objective of this study was to compare treatment outcomes of patients with depressive disorders treated remotely by means of telepsychiatry to outcomes of depressed patients treated in person. Secondary objectives were to determine if patients' rates of adherence to and satisfaction with treatment were as high with telepsychiatric as with in-person treatment and to compare costs of telepsychiatric treatment to costs of in-person treatment.

Development of a training module on therapeutic boundaries for mental health clinicians and case managers.

This article describes the development of a training model to teach mental health clinicians and case managers about therapeutic boundaries. Awareness of boundary transgressions is vital for establishing and maintaining the moral and ethical integrity of mental health treatment. Our structured teaching model was presented to staff from many different treatment settings throughout our mental health organization.

Stereospecific photochemical ring expansion of lithiated benzamides.

Treatment of N-benzyl benzamides with a strong base (LDA or t-BuLi) followed by irradiation with a 500 W tungsten lamp provides, according to the substitution pattern of the starting amides, either norcaradienes or cycloheptadienones by overall insertion of the N-benzyl group into the benzamide's aromatic ring system. Chiral benzamides undergo the ring expansion with high (sometimes complete) stereospecificity. The reaction appears to occur via a series of pericyclic reactions (photochemical or thermal sigmatropic rearrangements and thermal electrocyclic reactions) following an initial dearomatizing cyclization.

Hemoglobin function in deep-sea and hydrothermal-vent endemic fish: Symenchelis parasitica (Anguillidae) and Thermarces cerberus (Zoarcidae).

Deep-sea hydrothermal vents probably provide the harshest physico-chemical conditions confronting metazoan animals in nature. Given the absence of information on hemoglobin (Hb) function in hydrothermal-vent vertebrates, and the complex molecular and functional adaptations observed in hydrothermal-vent invertebrates, we investigated the oxygenation reactions of Hbs from the vent-endemic zoarcid Thermarces cerberus and the deep-sea anguillid Symenchelis parasitica from adjacent habitats. Electrophoretically cathodic and anodic isoHbs from S.

Competency evaluations in a VA hospital. A 10-year perspective.

The authors reviewed all 228 competency evaluations performed at the Baltimore VA Medical Center during a 10-year period. Between 1980 and 1984 and 1985 and 1989, the rate of inpatients who had competency evaluations increased from 0.20% to 0.

Temperature adaptation of fish hemoglobins reflected in rates of autoxidation.

Observation of rapid autoxidation of oxyhemoglobin (HbO2) from a deep-sea fish (Co-ryphaenoides acrolepis) prompted a survey of rates of autoxidation of HbO2 to methemoglobin in vitro from fishes inhabiting vastly different depths (1 to 3800 m) in order to discover any relationship between autoxidation rates and different environmental temperatures and pressures to which hemoglobins may be adapted. The rate of autoxidation was found to be sensitive to temperature in both deep- and shallow-living fishes. Hemoglobin appears to be thermally adapted since autoxidation was 10 times faster at all temperatures tested with HbO2 obtained from a cold-adapted fish (Coryphaenoides armatus variabilis) than from a comparatively warm-adapted one (Paralabrax nebulifer).

Enzymatic reactions involving orthoarsenate: arsenate is competitive with sulfate in the ATP sulfurylase reaction.

In the presence of ATP, Mg2+, and arsenate, ATP sulfurylase from yeast will catalyze the formation of inorganic pyrophosphate. Inorganic pyrophosphate was detected by determination of orthophosphate in the presence of inorganic pyrophosphatase. Two moles of Pi were found for each molecule of ATP in the reaction mixture.

Reactions of lipoamide dehydrogenase and glutathione reductase with arsonic acids and arsonous acids.

Lipoamide dehydrogenase reacts irreversibly with arsonous acids, RAs(OH)2, and arsonic acids, RAs(O)(OH)2, to form enzyme-inhibitor complexes. The formation of inactive enzyme requires NADH and is kinetically first order in the presence of excess arsonous acid. The second-order rate constant for formation of the enzyme-inhibitor complex was 545 min-1 M-1 for phenylarsonous acid, C6H5As(OH)2, and 5640 min-1 M-1 for methanearsonous acid, CH3As(OH)2.

Determination of equilibrium constants for a sequential model of dioxygen binding by hemoglobin-inositol hexaphosphate complexes: the structural pathway from deoxy- to oxy-hemoglobin.

The affinity of human hemoglobin (Hb4) for dioxygen was determined in 0.050 M bistris, 0.005 M inositol hexaphosphate (IHP) at pH 7.

Application of 19F NMR spectroscopy to a study of carbon monoxide binding to human hemoglobin modified at Cys-beta 93 with the S-trifluoroethyl residue.

The S-2,2,2-trifluoroethyl residue (-SCH2CF3) has been incorporated into human hemoglobin, Hb4(SH)2, as a reporter group at Cys-beta 93 using a sequence of disulfide interchange reactions [F. C. Knowles (1981) Anal.

Mode of action of a herbicide : johnsongrass and methanearsonic Acid.

Johnsongrass (Sorghum halepense (L.) Pers.) is sensitive to methanearsonate, foliar application resulting in a topkill.