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We have isolated mutants of Escherichia coli that have an altered beta-galactoside transport system. This altered transport system is able to transport a sugar, maltose, that the wild-type beta-galactoside transport system is unable to transport. The mutation that alters the specificity of the transport system is in the lacY gene, and we refer to the allele as lacYmal. The lacYmal allele was detected originally in strains in which the lac genes were fused to the malF gene. Thus, as a result of gene fusion and isolation of the lacYmal mutation, a new transport system was evolved with regulatory properties and specificity similar to those of the original maltose transport system. Maltose transport via the lacYmal gene product is independent of all of the normal maltose transport system components. The altered transport system shows a higher affinity than the wild-type transport system for two normal substrates of the beta-galactoside transport system, thiomethyl-beta-D-galactoside and o-nitrophenyl-beta-D-galactoside.

The focusing equations for uniform field magnetic sectors with circular edges are shown to have second-order double focusing solutions. The numerical methods used to find the appropriate magnetic sector parameters for moderate pole face separations are described. An electron spectrometer constructed for a field-emmission-gun-equipped Philips EM400 is shown to have an energy resolution of 0.5 eV at a sector half acceptance angle of 1 mrad.

The onset of rhythmic activities was compared for 2 groups of high-risk infants (a preterm Respiratory Distress Syndrome and a postterm postmature group) and a normal term group over their 1st year of life. The postterm postmature group experienced earlier onsets of rhythmic activities. The preterm RDS group showed delays in the onset of rhythmic activities, but when a correction was made for the prematurity, did not differ from the other groups. These differences suggest that the onset dates for rhythmic activities are not affected by the perinatal complications of RDS or postmaturity, but are related to gestational age differences. A comparison of the 3 groups on Bayley 1st-year motor skills revealed group differences even after an adjustment for gestational age differences, suggesting that the development of motor skills, unlike the development of rhythmic activities, may have been affected by these perinatal complications.

Active accumulation of maltose and maltodextrins by Escherichia coli depends on an outer-membrane protein. LamB, a periplasmic maltose-binding protein (MalE, MBP) and three inner-membrane proteins, MalF, MalG and MalK. MalF and MalG are integral transmembrane proteins, while MalK is associated with the inner aspect of the cytoplasmic membrane via an interaction with MalG. Previously we have shown that MBP is essential for movement of maltose across the inner membrane. We have taken advantage of malF and malG mutants in which MBP interacts improperly with the membrane proteins. We describe the properties of malE mutations in which a proper interaction between MBP and defective MalF and MalG proteins has been restored. We found that these malE suppressor mutations are able to restore transport activity in an allele-specific manner. That is, a given malE mutation restores transport activity to different extents in different malF and malG mutants. Since both malF and malG mutations could be suppressed by allele-specific malE suppressors, we propose that, in wild-type bacteria, MBP interacts with sites on both MalF and MalG during active transport. The locations of different malE suppressor mutations indicate specific regions on MBP that are important for interacting with MalF and MalG.

The development of 40 postterm, postmature infants was compared to that of 40 normal control infants during the first year of life. The postterm, postmature infants had more prenatal complications and received lower Brazelton interaction and motor scores at birth. At four months they scored lower on the Denver developmental scale and were rated "difficult" babies by their mothers. At eight months their Bayley motor scores were equivalent to those of the control infants, but their mental scores were lower. At this time their mothers reported a higher incidence of illnesses and of feeding and sleep disturbances.