Discovery and Characterization of New Hydroxamate Siderophores, Baumannoferrin A and B, produced by Acinetobacter baumannii.

Acinetobacter baumannii AYE does not produce acinetobactin but grows under iron limitation. Accordingly, analyses of AYE iron-restricted culture supernatants resulted in the isolation of two fractions, which contained only hydroxamates and showed siderophore activity. Structural analyses identified baumannoferrin A and baumannoferrin B, which differ only by a double bond. These siderophores are composed of citrate, 1,3-diaminopropane, 2,4-diaminobutyrate, decenoic acid, and α-ketoglutarate. Analysis of the AYE genome showed the presence of a 12-gene cluster coding for proteins similar to those involved in the production and utilization of the hydroxamate siderophores acinetoferrin and achromobactin. As A. baumannii AYE does not produce acinetobactin and harbors only one gene cluster encoding the production and utilization of a siderophore, this strain's growth under iron limitation depends on baumannoferrin, a novel hydroxamate that could play a role in its virulence.

Student Factors That Influence Clerkship Grades and Matching Into a Surgical Residency.

OBJECTIVE: Evaluate the relationship between medical school factors (including preclinical mentorship, order of clerkships, and clerkship grades) and matching into surgical specialties. DESIGN: Clerkship information, match data, and data on structured preclinical research obtained from 2010 to 2015 for a single institution was obtained and analyzed using multivariate analysis. SETTING: University of Michigan Medical School. PARTICIPANTS: Seven hundred and forty-six students who took both the Internal Medicine and Surgery clerkships between 2010 and 2015 and have since participated in the match. RESULTS: Among 740 students studied, 243 matched into a surgical field. Higher Shelf scores were associated with higher clerkship grades in Surgery and Internal Medicine. Honors or High Pass in Surgery were associated with matching into a surgical field. Structured preclinical research in Surgery and order of clerkship were not associated with matching into a surgical field. CONCLUSIONS: Students who went into surgery were more likely to receive Honors or High Pass. Preclinical choices geared toward a surgical specialty (e.g., order of clerkship and structured research) were not associated with matching into a surgical field. These data may help guide school specific advice for students.

Simultaneous liquid chromatographic determination of doxorubicin and its major metabolite doxorubicinol in parrot plasma.

A new microscale method is reported for the determination of doxorubicin and its active metabolite, doxorubicinol, in parrot plasma. Sample workup involved acetonitrile protein precipitation, ethyl acetate extraction, followed by back extraction into HCl. Separations were achieved on a phenyl-hexyl column at 30 degrees C using acetonitrile (17%, v/v) in 0.01 M orthophosphoric acid (83%, v/v) delivered via a linear flow program. Fluorometric detection wavelengths were 235 nm (excitation) and 550 nm (emission). Calibration plots were linear (r2>0.999), and recoveries were 71-87% from 20 to 400 ng/mL. Assay imprecision was