The N protein of bacteriophage lambda, defined by its DNA sequence, is highly basic.

Nucleotide sequence has been determined for the restriction fragments and cloned DNA from the pL-N-tL1 region of bacteriophage lambda. A unique reading frame for the N gene is defined by the absence of natural nonsense codons and by the presence of seven nonsense codons generated by mutations in N. This reading frame is initiated at two alternative ATG codons, the second of which is probably the in vivo translation start. Reading is stopped at a single TAG codon. The protein coded is therefore 133 or, more probably, 107 amino acids long, rich in lysine, arginine and proline.     

The amino acid sequence of “heavy chain disease” protein ZUC. Structure of the Fc fragment of immunoglobulin G3

The sequence of the Fc fragment of human IgG3 was studied, using a naturally-occurring γ3 heavy chain variant (ZUC). Though the molecule is internally deleted, it contains 248 residues, including the entire Fc fragment. The almost complete sequence of the C_H2 and C_H3 domains (position 234 to 446) indicates an extremely close evolutionary relationship with γ1 and γ4 chains. There is a 95% homology between IgG3 and IgGl and 92% between IgG3 and IgG4 in the C_H2 in the C_H3 domains.     

Mitochondrial isocitrate dehydrogenase and isocitrate oxidation of rat ventral prostate.

Mitochondrial preparations isolated from rat ventral prostate were capable of oxidizing isocitrate by way of NADP isocitrate dehydrogenase (NADP-IDH) and NAD-IDH. NAD-IDH activity required ADP for activation. The pH responses for NAD-IDH and NADP-IDH were quite different. The results indicated that two different enzymes were involved in the NAD- and NADP-IDH activities. Indirect evidence indicated that NADPH-NAD transhydrogenase activity might also be involved in the mitochondrial pathway for isocitrate oxidation. NADP-IDH activity was significantly greater than NAD-IDH activity. The oxidation of isocitrate through IDH activity was coupled to the cytochrome system by NADPH- and NADH-cytochrome c reductase activities. Citrate, via isocitrate, oxidation proceeded at a much slower rate suggesting that aconitase activity could be limiting in the oxidation of citrate. In comparison to other tissues, the prostate oxidative enzyme activities are considerably lower. The results suggest that the accumulation of high prostate citrate levels is not due to a limitation imposed by a lack of IDH activity in prostate mitochondria.     

The initial attachment of transforming DNA to competent Bacillus subtilis.

Summary The initial attachment of transforming DNA to competent Bacillus subtilis is temperature independent between 25° and 45°. However, below 15° there is a significant reduction in the amount of DNA attached to competent cells. The DNA that is attached at 4° can lead to transformation or interfere effectively with the subsequent attachment of a distinctive DNA when the cells are shifted to a permissive temperature (37°). These data suggest that the attachment of DNA at 4° is to sites normally involved in the transformation process. The amount of DNA that is initially attached to the bacteria at 4° or 37° after perturbation of the cells by ionic strength changes, repetitive washings, or periodate oxidation varies with the temperature at which the treatment occurs. These results are consistent with a reorientation of the DNA attachment sites upon lowering the temperature to 4°, such that their affinity for DNA and susceptibility inhibitory treatments are reduced.National Institutes of Health Research Career Program Awardee, CA-K3-6487 during a portion of this investigation.     

Review of acute severe asthma.

Status asthmaticus in the 1980s is still occasionally a fatal disorder. Preventable causes appear to be common: failing to appreciate the severity of the illness and undertreatment, particularly with steroids. Thus, an objective data base, early treatment, and frequent reassessment are of paramount importance. Despite intensive therapeutic intervention, mechanical ventilation may be required. In managing the ventilator in these patients, efforts should be directed at minimizing peak airway pressures while vigorous conventional modalities are continued. The need to use mechanical ventilation does not imply that the course of the disease will worsen, and the long-term outlook generally is good. Thus, even a low mortality rate is troubling. Once the acute process has resolved, educating the patient and close follow-up are essential.     

Nerve conduction theory: Some mathematical consequences of Bernstein's model

The generally accepted permeability theory of nerve conduction is presented in mathematical form. The resulting velocity formula is found to agree well with data on squid giant axon, but predicts velocities considerably too high in the case ofNitella. The dependence of velocity on fiber diameter is discussed for both medullated and non-medullated nerve, it being shown theoretically that velocity is proportional to the square root of diameter for non-medullated and to the diameter for medullated nerve. The equations relating the shape of the action spike to the observed permeability changes are given but are not solved.     

More than skin and bones: Comparing extraction methods and alternative sources of DNA from avian museum specimens

Next‐generation sequencing has greatly expanded the utility and value of museum collections by revealing specimens as genomic resources. As the field of museum genomics grows, so does the need for extraction methods that maximize DNA yields. For avian museum specimens, the established method of extracting DNA from toe pads works well for most specimens. However, for some specimens, especially those of birds that are very small or very large, toe pads can be a poor source of DNA. In this study, we apply two DNA extraction methods (phenol–chloroform and silica column) to three different sources of DNA (toe pad, skin punch and bone) from 10 historical avian museum specimens. We show that a modified phenol–chloroform protocol yielded significantly more DNA than a silica column protocol (e.g., Qiagen DNeasy Blood & Tissue Kit) across all tissue types. However, extractions using the silica column protocol contained longer fragments on average than those using the phenol–chloroform protocol, probably as a result of loss of small fragments through the silica column. While toe pads yielded more DNA than skin punches and bone fragments, skin punches proved to be a reliable alternative source of DNA and might be especially appealing when toe pad extractions are impractical. Overall, we found that historical bird museum specimens contain substantial amounts of DNA for genomic studies under most extraction scenarios, but that a phenol–chloroform protocol consistently provides the high quantities of DNA required for most current genomic protocols.