Multiple xylanases of Cellulomona fimi are encoded by distinct genes

Cellulomonas fimi genomic DNA encoding xylanase activity has been cloned and expressed in Escherichia coli. As judged by DNA hybridization and restriction analysis, twelve xylanase-positive clones carried a minimum of four different xylanase (xyn) genes. The encoded enzymes were devoid of cellulase activity but three of the four bound to Avicel.     

Primary Amoebic Meningoencephalitis in Britain

Meningoencephalitis proved to be due to an amoeba (Naegleria) has been diagnosed in Great Britain for the first time. The first patient (a boy of 2) survived longer than any previously recorded cases, but in spite of early diagnosis and treatment he died 15 days after the onset of meningeal symptoms.Two other children who were exposed to the same possible source of infection (a warm, muddy puddle) had similar symptoms and developed mild meningitis. A naegleria was isolated from the cerebrospinal fluid of one of them. Both recovered after treatment with amphotericin.     

Influences of bacterial DNA base-ratios and amino acid composition of the gene product on the consequences of frameshift mutations

Using as an example the E. coli lac I (repressor) gene product, it can be shown that DNA base-ratio is a major determinant of the detailed outcomes of both +1 (?2) and ?1 (+2) types of frameshift mutations. Potential reinitiation codons (AUG or GUG) and premature stop codons (UAA, UAG and UGA) occur in very different proportions depending on the type of frameshift and the DNA base-ratio.A comparison of the H. halobium bacteriorhodopsin precursor gene with other actual and theoretical genes reveals that the amino acid composition of the gene product is a second, important, determinant of the detailed outcome of frameshift mutations. Rules are formulated for the occurrence of particular codon, and hence amino acid, doublets in AT-GC-rich or intermediate base-ratio DNA as these affect frameshift-generated reinitiation and premature stop codons.     

Patterns of sexual behavior in male macaques

One large social group of each of three species of macaques (Macaca mulatta, M. fascicularis, M. radiata), housed in half-acre field cages at the California Primate Research Center, were observed for a total of 150 h. Data on sexual behavior and dominance interactions were recorded by pairs of experienced observers using a focal animal technique. Single or multiple mount-to-ejaculation sequences, number of thrusts per mount, number of mounts per sequence, duration of mounts per sequence, duration of sequences, social rank and frequency of sexual activity were recorded for each adult male. M. mulatta used a multiple mount-to-ejaculation (MME) pattern in 91% of their copulations. M. radiata used a single mount-to-ejaculation (SME) pattern in 91% of their copulations. M. fascicularis used both patterns—53% MME and 47% SME. A positive correlation was found between rank and sexual activity in fascicularis and mulatta males. A negative correlation between rank and sexual activity was found in radiata males and also a positive correlation between rank and age indicating that the youngest and most subordinate radiata males were the most sexually active males. In reviewing the literature, a relationship between degree of intermale competition, intermale tolerance and type of mounting pattern was revealed. Macaque species that primarily use an SME pattern also show sa high degree of intermale tolerance and little interrnale competition. Macaque species that primarily use an MME pattern typically show a high degree of intermale competition and a low degree of intermale tolerance. Possible events leading to such relationships are discussed.     

Temperature and embryonic development in polar marine invertebrates

The life-history tactics of many Antarctic marine invertebrates suggest that the commonly observed slow rates of growth are adaptations to the pattern of food availability, and not due to low temperature per se. This implies that marine invertebrates have been able, over the course of evolutionary time, to compensate their rates of embryonic development for the effect of temperature. Data from north Atlantic copepods indicate that this is so. It is therefore suggested that the slow rates of embryonic development in many Antarctic marine invertebrates are the result of large egg size, and not the low temperature. Large, slowly developing eggs are part of a suite of tactics, often called K-strategies, which characterise many marine invertebrates in Antarctica.     

Determination of fetal biparietal diameter without the use of ultrasound in squirrel monkeys

This study evaluated manual caliper measurement of fetal BPD in Saimiri through the abdomen of the dam (TBPD) for correlation with paired ultrasound measurements, prediction of delivery date, subspecies variation, prediction of pregnancy outcome, and correlation between postpartum BPD and TBPD. Regression analysis revealed a close relationship between TBPD measurements and those obtained by ultrasound (P < 0.001). TBPD for Saimiri boliviensis boliviensis increased from a mean of 14.8 ± 0.3 mm for 11 weeks prepartum to a delivery week measurement of 33.2 ± 0.2mm. Delivery-week TBPD of Saimiri boliviensis peruviensis were significantly smaller than Saimiri sciureus sciureus (P < .05). Delivery week TBPD had a correlation coefficient of 0.64 with paired post-patrum measurements. No complications were associated with the technique. Delivery date could be predicted within two weeks. TBPD is an inexpensive, safe, rapid method of approximating fetal growth during the last half of pregnancy in Saimiri.     

Quantitative immunochemical studies of myosin in Dictyostelium discoideum

We have isolated monoclonal antibodies against myosin from the eukaryotic microorganism Dictyostelium discoideum. Immunoblot analysis using chymotryptic fragments of myosin has shown that the 17 antibodies are directed against at least five different sites on the myosin heavy chain. Using an antibody (M342) that reacts with an epitope on the tail portion of the myosin molecule, we have developed an assay to quantitate myosin in whole cells and subcellular fractions. Samples are deposited on nitrocellulose paper using a filtration manifold and are probed with metabolically labeled M342 antibodies. The assay is rapid and sensitive; it permits the measurement of myosin even in crude cell lysates that contain detergent. By use of the filtration immunoassay, we have found that myosin constitutes 0.72% of the total protein in vegetative amoebae. We have also determined that Triton-resistant cell residues (cytoskeletons or cortical actin matrices) prepared in the absence of ATP contain nearly half of the cell's myosin. If ATP is present, 98% of that myosin is released, although actin levels do not diminish.