AN AMPLIFICATION OF THE PHYLOGENETIC SPECIES CONCEPT

Abstract— The goal of a phylogenetic species concept is to reveal the smallest units that are analysable by cladistic methods and interpretable as the result of phylogenctic history. We define species as the smallest aggregation of populations (sexual) or lineagcs (asexual) diagnosable by a unique combination of character states in comparable individuals (semaphoronts). A character state is an inherited attribute distributed among all comparable individuals (semaphoronts) of the same historical population, clade, or terminal lineage. This definition of species is character-based and pattern oriented. Evolutionary explanations of phylogenetic species are consistent with contemporary explanations of processes of speciation, but require only the assumption of nested hierarchical pattern. We discuss the compatibility of the phylogenetic species concept with various biological needs for species and justify its use at the exclusion of alternative species concepts.     

Regulation of Brain and Cerebrospinal Fluid Calcium by Brain Barrier Membranes Following Vitamin D-Related Chronic Hypo- and Hypercalcemia in Rats

Male Fischer-344 rats, 21 days old, were fed diets containing 0 (LOD), 2,200 (CONT), or 440,000 (HID) international units of vitamin D3 per kilogram for 12 weeks. [Ca] was measured in plasma, CSF, brain, and choroid plexus. In addition, 45Ca and 36Cl transfer coefficients (KCa and KCl) for uptake from blood into CSF and brain were determined. Although plasma ionized [Ca]s in LOD and HID rats were 50% and 136%, respectively, of values in CONT animals, CSF and brain [Ca]s ranged from only 85% to 110% of respective CONT values. Choroid plexus [Ca] was increased by 37% after HID diet, but was decreased only 10% after LOD. KCa values at CSF, parietal cortex, and pons-medulla were negatively correlated with plasma ionized [Ca], whereas KCl values at CSF and brain were not different between the diet groups. The findings demonstrate that central nervous system [Ca] is maintained during chronic hypo- or hypercalcemia by saturable transport of Ca at brain barrier membranes. This transport does not seem to involve modulation by 1,25-dihydroxyvitamin D3.     

Cardiovascular responses to intrathecal administration of arginine vasopressin in rats

Arginine vasopressin (AVP) has been localized in numerous extrahypothalamic brain regions and in the spinal cord. The results of intracerebroventricular AVP injections and microinjection of AVP into the brain stem suggest that this peptide, acting centrally at higher levels, may influence cardiovascular function. No function for the AVP occurring at spinal levels has been reported. In this study we report that AVP, in picomole quantities, increased arterial blood pressure and integrated heart rate in a dose-dependent manner following intrathecal application to the thoracic region in the rat. This response was not blocked by intravenous administration of the AVP antagonist d(CH₂)₅-d-Tyr-VAVP. These results suggest that AVP, acting within the spinal cord, may alter neural outflow regulating blood pressure and heart rate.     

The search for new industrial crops

Advances in technological development have produced an ever-increasing pressure for new and different raw materials to keep pace with changing industrial needs. Many new and useful properties of plants may be discovered through the modern chemistry and technology of utilization research. The U. S. Department of Agriculture’s search for new industrial crops is a coordinated botanical and utilization research program.     

Myocardial Revascularization in Patients 70 Years of Age and Older

Myocardial revascularization has been carried out by us in 67 patients 70 years of age or older. Advanced coronary artery disease was found at angiography in more than two thirds of the patients. The postoperative morbidity and mortality compare very favorably with those in younger patients. The early and late mortality in the 67 patients was 4.5 percent and 6.0 percent, respectively. Fifty-seven survivors have been followed an average of 21 months; for most patients there has been a pronounced improvement in clinical classification. Properly selected, patients of advanced age can undergo successful revascularization surgical procedures. The adequacy of function of the left ventricle, proper timing of the surgical operation and an aggressive yet realistic approach seem to be major determinants for a good result.     

Identification of baculovirus gene that promotes Autographa californica nuclear polyhedrosis virus replication in a nonpermissive insect cell line.

A gene that promotes Autographa californica M nuclear polyhedrosis virus (AcMNPV) replication in IPLB-Ld652Y cells, a cell line that is nonpermissive for AcMNPV, was identified in Lymantria dispar M nuclear polyhedrosis virus (LdMNPV). Cotransfection of AcMNPV DNA and a plasmid carrying the LdMNPV gene into IPLB-Ld652Y cells results in AcMNPV replication. The gene maps between 43.3 and 43.8 map units on the 162-kbp genome of LdMNPV. It comprises a 218-codon open reading frame and encodes a polypeptide with a predicted molecular mass of 25.7 kDa. The predicted polypeptide is glutamic acid and valine rich and negatively charged, with a pI of 4.61. No protein sequence motifs were identified, and no matches with known nucleotide or peptide sequences were found in the AcMNPV genome or database searches that suggest how this gene might function. A recombinant AcMNPV bearing the LdMNPV gene overcomes a block in protein synthesis observed in AcMNPV-infected IPLB-Ld652Y cells. Using Southern blotting techniques, we were unable to identify a homolog in Orgyia pseudotsugata M nuclear polyhedrosis virus, a baculovirus that is routinely propagated in IPLB-Ld652Y cells. This suggests that the LdMNPV host range is unique among the baculoviruses studied to date. We named this gene hrf-1 (for host range factor 1).