Phosphorylation of dipteran chromosomes and rat liver nuclei.

Side-chain modifications of the nucleoproteins are believed to be involved in the control of gene function. Rat liver nuclei and chromatin incubated in adenosine triphosphate labeled in the gamma position with phosphorus-32 demonstrated rapid phosphorylation in vitro of the nuclear proteins. Dipteran salivary glands incubated in either labeled adenosine triphosphate or ortho-phosphate labeled with phosphorus-32 showed that there is phosphorylation of chromosomal protein. The phosphorus is associated in protein from both liver and salivary gland nuclei predominantly with phosphoserine.

Gene transfer in crop improvement.

Transfer of genes between plant species has played an important role in crop improvement for many decades. Useful traits such as resistance to disease, insects, and stress have been transferred to crop varieties from noncultivated plants. Recombinant DNA methods greatly extend (even outside the plant kingdom) the sources from which genetic information can be obtained for crop improvement. Gene transfer systems based on recombinant DNA are available for several crop species and are under development for others. The concerted use of traditional and more recent methods for plant genetic manipulation will contribute to crop improvement.

Circular dichroism and fluorescence studies on potato virus X and its structural components.

Circular dichroism (DC) measurements of the coat protein subunits of potato virus X show that native subunits that can reassemble with RNA to form infectious virus particles have appreciable alpha-helical structure. The CD of intact potato virus X was less intense below and more intense above 250 nm, and the maxima and minima were at longer wavelengths, than those of a CD spectrum computed from the individual contributions of the coat protein and RNA. The differences between the measured and computed spectra below 250 nm were attributed to the effects of differential light scattering and absorption flattening on measurements of the virus particle CD. The differences at longer wavelengths, were the CD contribution of the nucleic acid predominates, probably reflect the difference between a base-paired conformation of the RNA in solution and the more rigid single-stranded conformation imposed by the structure of the virus. The CD evidence suggests that the tertiary structure and potato virus X coat protein subunits in solution and in intact virus particles is similar. Both CD and fluorescence emission results indicate differences between the tryptophan environment in dissociated protein subunits and that in intact virus. These are attributed to local differences in subunit conformation or to the occurrence of intersubunit interactions involving tryptophan in the intact virus.

Molecular biological access to the chemistry of unknown soil microbes: a new frontier for natural products.

Cultured soil microorganisms have provided a rich source of natural-product chemistry. Because only a tiny fraction of soil microbes from soil are readily cultured, soil might be the greatest untapped resource for novel chemistry. The concept of cloning the metagenome to access the collective genomes and the biosynthetic machinery of soil microflora is explored here.

Up-regulation of OsBIHD1, a rice gene encoding BELL homeodomain transcriptional factor, in disease resistance responses.

In the present study, we cloned and identified a full-length cDNA of a rice gene, OsBIHD1, encoding a homeodomain type transcriptional factor. OsBIHD1 is predicted to encode a 642 amino acid protein and the deduced protein sequence of OsBIHD1 contains all conserved domains, a homeodomain, a BELL domain, a SKY box, and a VSLTLGL box, which are characteristics of the BELL type homedomain proteins. The recombinant OsBIHD1 protein expressed in Escherichia coli bound to the TGTCA motif that is the characteristic cis-element DNA sequence of the homeodomain transcriptional factors. Subcellular localization analysis revealed that the OsBIHD1 protein localized in the nucleus of the plant cells. The OsBIHD1 gene was mapped to chromosome 3 of the rice genome and is a single-copy gene with four exons and three introns. Northern blot analysis showed that expression of OsBIHD1 was activated upon treatment with benzothiadiazole (BTH), which is capable of inducing disease resistance. Expression of OsBIHD1 was also up-regulated rapidly during the first 6 h after inoculation with Magnaporthe grisea in BTH-treated rice seedlings and during the incompatible interaction between M. grisea and a resistant genotype. These results suggest that OsBIHD1 is a BELL type of homeodomain transcription factor present in the nucleus, whose induction is associated with resistance response in rice.

The Earth's bounty: assessing and accessing soil microbial diversity.

The study of microbial diversity represents a major opportunity for advances in biology and biotechnology. Recent progress in molecular microbial ecology shows that the extent of microbial diversity in nature is far greater than previously thought. Here, we discuss methods to analyse microorganisms from natural environments without culturing them and new approaches for gaining access to the genetic and chemical resources of these microorganisms.

Activity of nitric oxide is dependent on, but is partially required for function of, salicylic acid in the signaling pathway in tobacco systemic acquired resistance.

When tobacco plants were treated by injection with nitric oxide (NO)-releasing compounds, the sizes of lesions caused by Tobacco mosaic virus (TMV) on the treated leaves and on upper nontreated leaves were significantly reduced. The reduction in TMV lesion size was caused by NO released from the NO-releasing compounds; the byproduct formed after release of NO from the NO-releasing compound NOC-18, diethylenetriamine, did not itself alter lesion size. Treatment of tobacco plants with inhibitors of nitric oxide synthase or an NO scavenger attenuated but did not abolish the systemic acquired resistance (SAR) induced by salicylic acid (SA). In NahG transgenic tobacco plants, NO had no effect on lesion size following TMV infection. These results are consistent with the hypothesis that NO plays an important role in SAR induction in tobacco and that NO is required for the full function of SA as an SAR inducer. The activity of NO is fully dependent on the function of SA in the SAR signaling pathway in tobacco.

A new multigene family inducible by tobacco mosaic virus or salicylic acid in tobacco.

A previously undescribed cDNA family was isolated from tobacco challenged with tobacco mosaic virus (TMV). A cDNA library was constructed with mRNA from upper leaves of Xanthi nc tobacco plants that had been inoculated with TMV on the lower leaves 11 days previously. The library was screened differentially with radiolabeled cDNA synthesized with mRNA from upper, uninoculated leaves of either TMV-inoculated or mock-inoculated tobacco plants. The new cDNA family, designated SAR8.2, had at least five expressed members, one or more of which were inducible by TMV inoculation and by salicylic acid treatment. The cDNAs encoded small, highly basic proteins containing N-terminal hydrophobic signal peptides and highly conserved cysteine-rich C-terminal domains. One of the SAR8.2 family members contained a direct repeat of the C-terminal domain in tandem. Hybridization of SAR8.2 cDNA to tobacco genomic DNAs indicated a gene family of 10-12 members.

Satisfaction with genetic counseling: dimensions and measurement.

Patient satisfaction has become a significant issue in evaluating medical care, although it has been largely neglected in genetic counseling. A 32-item questionnaire was designed to examine patient satisfaction and was administered to 76 clients in a genetic counseling center, and 56 parents attending a pediatric outpatient clinic (the control group). Factor analysis showed 3 dimensions to satisfaction with genetic counseling: instrumental, affective, and procedural. The general level of satisfaction was found to be lower in the genetic counseling group than in the control group. This finding was interpreted as expressing basic properties of genetic counseling. The most important determinant of satisfaction in both groups was satisfaction with the content of information provided in counseling. Some affective and procedural aspects of genetic counseling were found more satisfying, and more important in determining genetic clients' general sense of satisfaction, as compared to the control subjects.

New form of postaxial acrofacial dysostosis?

We report on a 2-month-old Sephardic Jewish girl with bilateral and symmetrical deficiency of the fifth digital rays of all 4 limbs, combined with severe deformations and other malformations of the limbs. These findings were associated with orofacial malformations, as well as with visceral anomalies differing from those found in other postaxial deficiency syndromes. Parents were closely consanguineous. We assume this patient represents a new form of postaxial acrofacial dysostosis.

Upper limb involvement in the Klein-Waardenburg syndrome.

Upper limb involvement in the Klein--Waardenburg (K--W) syndrome is documented in two affected sibs and in four other previously reported patients. In addition to the key facial and auditory findings observed in the Waardenburg syndrome type I, these patients have such bilateral upper limb defects as hypoplasia of the musculoskeletal system, flexion contractures, fusion of the carpal bones, and syndactyly. The cause of the K--W syndrome is not known although there is some evidence for autosomal dominant inheritance, but further documentation is needed before this can be considered conclusive.

Concordance of auriculo-cardiovascular-skeletal malformations: a new malformation complex in an infant of a diabetic mother?

The incidence of malformations among infants of diabetic mothers (IDM) is known to be higher than in the general population. These malformations usually involve several organ systems and in the past few years there has been an attempt to group them into distinct "syndromes." The present report concerns a child with a specific constellation of findings not yet reported in the infant of a diabetic mother, and we urge our colleagues to look for other associations existing in these infants, rather than just listing series of individual malformations.

Symphalangism with multiple anomalies of the hands and feet: a new genetic trait.

We report a new autosomal dominant condition involving hands and feet of an Arabic father and 5 of his 11 children. This trait is characterized by symphalangism, syndactyly, brachydactyly type D, clinodactyly, and hypoplasia of the thenar and hypothenar eminences. Affected persons had symphalangism and syndactyly plus some or all or part of the other anomalies. Symphalangism, the main defect in this syndrome, showed variable expressivity. A distinct dermatoglyphic pattern was observed in all affected relatives. Linkage studies were done; however, no linkage was demonstrated.

Progressive spastic paraparesis, vitiligo, premature graying, and distinct facial appearance: a new genetic syndrome in 3 sibs.

We describe progressive spastic paraparesis of the lower limbs in the presence of generalized vitiligo, premature graying of body hair, and distinct facial appearance in 3 sibs whose parents are first cousins. The condition is considered an autosomal recessive trait. The pathogenesis of this neurocutaneous disorder is unknown.

Effects of S-carboxymethylcysteine on tracheal mucus velocity.

The effects of S-carboxymethylcysteine on tracheal mucus velocity were assessed in a double blind crossover study between 2 grams S-carboxymethylcysteine and placebo. Subjects included six healthy non-smokers, eight smokers with small airway disease and chronic simple bronchitis, and eight subjects with chronic obstructive bronchitis. Tracheal mucus velocity was measured prior to and two and three hours after each subject had ingested S-carboxymethylcysteine or placebo. No significant change in tracheal mucus velocity occurred after placebo or S-carboxymethylcysteine in any of the groups, indicating that the drug has no acute effect on mucus transport.

Primary retinal dysplasia transmitted as X-chromosome-linked recessive disorder.

The familial occurrence of retinal dysplasia in five affected male children suggested X-chromosome-linked recessive inheritance. The clinical features were childhood onset, severe visual impairment, head posture, nystagmus, and strabismus. The ophthalmoscopic findings varied in shape and extension; they ranged from retinal folds to dysplastic tissue covering the posterior pole or gliosis with tumor-like protrusion in the vitreous. The marked variability of the retinal findings was paralleled by the visual acuity, which ranged from some vision to blindness. Electroretinograms coordinated well with ophthalmoscopic observations. Of the five mothers, who are the presumed heterozygous carriers, two showed retinal changes.

Autosomal dominant inheritance of retinoschisis.

Hereditary retinoschisis affected eight members of three generations of a family. The mode of transmission and the clinical features were not compatible with findings noted in either X-chromosome-linked or autosomal recessive forms of retinoschisis. The genetic and clinical features in this family strongly supported autosomal dominant inheritance, adding to the known genetic heterogeneity for the hereditary forms of retinoschisis. The expression of the condition varied in severity, but all affected members of the family had peripheral retinoschisis and peripheral retinal degeneration. Three had maculoschisis and five had macular pigmentary changes. Electroretinographic findings were normal in six of the eight.

Spontaneous spinal cord "injury potential" in the rat.

A marked ionic change in both the intra- and the extracellular space at the site of an acute spinal cord lesion has been reported in the literature. The present study was undertaken to measure spontaneous electrical potentials that might be associated with the previously observed ionic shifts. With the use of an impact (weight drop) model of cord injury in rats, lesions were induced at T-8. DC potentials were measured simultaneously both rostrally and caudally with respect to site of injury over a time course of 4 hours after injury. The potentials were positive with respect to lesion site, and the intensity decreased with time during 4 hours of observation. These results seem to support reported ionic shifts and migrations in injured cords and represent, to our knowledge, the first reported measurement of spontaneous injury potential in the cord of a mammal.

Modeling dose-response relationships in biological control: partitioning host responses to the pathogen and biocontrol agent.

ABSTRACT Breeding plants to improve the effectiveness of biocontrol agents is a promising approach to enhance disease suppression by microorganisms. Differences in biocontrol efficacy among cultivars suggest there is genetic variation for this trait within crop germplasm. The ability to quantify host differences in support of biological control is influenced by variation in host response to the pathogen and the dose of pathogen and biocontrol agent applied to the host. To assess the contribution of each of these factors to successful biocontrol interactions, we measured disease over a range of pathogen (Pythium) and biocontrol agent (Bacillus cereus UW85) inoculum doses. We fit dose-response models to these data and used model parameter estimates to quantify host differences in response to the pathogen and biocontrol agent. We first inoculated eight plant species separately with three species of Pythium and evaluated three dose-response models for their ability to describe the disease response to pathogen inoculum level. All three models fit well to at least some of the host-pathogen combinations; the hyperbolic saturation model provided the best overall fit. To quantify the host contribution to biological control, we next evaluated these models with data from a tomato assay, using six inbred tomato lines, P. torulosum, and UW85. The lowest dose of pathogen applied revealed the greatest differences in seedling mortality among the inbred lines, ranging from 40 to 80%. The negative exponential (NE) pathogen model gave the best fit to these pathogen data, and these differences corresponded to model parameter values, which quantify pathogen efficiency, of 0.023 and 0.091. At a high pathogen dose, we detected the greatest differences in biocontrol efficacy among the inbred lines, ranging from no effect to a 68% reduction in mortality. The NE pathogen model with a NE biocontrol component, the NE/NE biocontrol model, gave the best fit to these biocontrol data, and these reductions corresponded to model parameter values, which quantify biocontrol efficiency, of 0.00 and 0.038, respectively. There was no correlation between the host response to the pathogen and biocontrol agent for these inbred lines. This work demonstrates the utility of epidemiological modeling approaches for the study of biological control and lays the groundwork to employ manipulation of host genetics to improve biocontrol efficacy.

Regression Analyses for Evaluating the Influence of Bacillus cereus on Alfalfa Yield Under Variable Disease Intensity.

ABSTRACT We developed and tested regression methods to exploit the variability in disease inherent in field experiments, and applied the methods to evaluate strains of Bacillus cereus for biocontrol efficacy. Four B. cereus strains were tested for their effect on alfalfa (Medicago sativa) performance in 16 field trials planted during 1993 to 1996 at multiple sites in Wisconsin. To evaluate performance of the strains, we used the ratio of (metalaxyl response)/(untreated control response) as a measure of disease intensity within the experiments. The ratio of (Bacillus response)/(untreated control response) was then regressed as a function of disease intensity. The slope of the resulting line provides a statistical test to compare performance of the Bacillus strain with that of the untreated seed (H(o): slope = 0) and metalaxyl controls (H(o): slope = 1). Under conditions in which disease occurred, forage yield of plots planted with seed treated with B. cereus strain AS4-12 exceeded yield from the untreated control plots (P = 0.002) and was similar to yield of plots planted with metalaxyl-treated seed (P = 0.14). Yield gain associated with AS4-12 and metalaxyl seed treatment averaged 6.1 +/- 2.8% (+/-standard error) and 3.0 +/- 2.8%, respectively. In contrast to the regression approach, means analysis by analysis of variance did not detect differences among treatments. Three other B. cereus strains either did not increase alfalfa yield or increased yield less than did AS4-12. Metalaxyl and three of the Bacillus strains increased seedling emergence, but the improved stands were not predictive of increased forage yield. In six additional studies conducted for one season in 1997, AS4-12 enhanced yield of two cultivars at diverse locations in Wisconsin, but there was an apparent cultivar-location interaction. A strong correlation between response to AS4-12 and metalaxyl treatment suggests that these treatments controlled similar pathogens, most likely the oomycete pathogens Phytophthora medicaginis and Pythium spp.