Changes in nucleic acids, protein and ribonuclease activity during maturation of peanut seeds

Changes in weight, protein, RNA, DNA and ribonuclease activityduring maturation of the peanut seed have been studied. Theinvestigation period began with fruits harvested four weeksafter the pegs turned at right angles in the soil and continuedthrough the fourteenth week. Fresh weights of both cotyledonsand embryonic axes increased rapidly during early maturation(8 weeks) and continued in the cotyledons through 12 weeks.The water content at maturity was still adequate for enzymaticprocesses at 45% and 39%, respectively, for embryonic axes andcotyledons. The levels of DNA and RNA also increased rapidlyduring early maturation of both cotyledons and embryonic axes.DNA content decreased during the remainder of maturation whileRNA decreased from 8 to 11 weeks in the cotyledons and thenincreased during the after-ripening period to a value near itsprevious maximum at 8 weeks. RNA levels in the embryonic axesunderwent a gradual increase throughout maturation. The largedecrease in cotyledonary RNA during weeks 8 through 11 couldbe related to increased RNase activity during the period. ¹ Paper number 3370 of the Journal Series of the North CarolinaState University Agricultural Experiment Station, Raleigh, NorthCarolina 27607, U. S. A. ² Present address: Department of Botany, Arts and Sciences,University of the Phillippines, Diliman, Q. C., Phillipines. (Received December 22, 1971; )     

The origins of Michael Conrad's research programs (1964-1979).

This paper summarizes Michael Conrad's academic and professional career from the time he began his Ph.D. studies in 1964 to his appointment at Wayne State University in 1979. It describes the origins of several of his major research interests and presents a personal evaluation of how this early work continues to be of fundamental importance.     

Extensive genetic divergence in the East Asian natricine snake,Rhabdophis tigrinus (Serpentes: Colubridae), with special reference to prominent geographical differentiation of the mitochondrial cytochrome b gene in Japanese populations

We investigated intraspecific phylogenetic relationships in the natricine snake, Rhabdophis tigrinus. A partial sequence of mitochondrial cytochrome b gene (990 bp) was sequenced for 220 individuals from 112 populations. The phylogeny indicated monophyly of the Japanese populations against the continental and Taiwanese populations, sister relationships of the Japanese and continental populations, and monophyly of the whole species. The results strongly suggested substantial genetic divergences among population assemblages from those three regions. We thus consider both lateralis from the continent, which is often synonymized to R. tigrinus, and formosanus from Taiwan, which is usually regarded as a subspecies of the latter, as distinct full species based on the evolutionary species concept. In the Japanese populations, haplotypes were classified to in two major clades (I and II) that were parapatric to each other. Clade I consisted of three distinct subclades (I‐A, I‐B, and I‐C), of which the former two were parapatric with each other, whereas the latter was sympatric with each of the former two subclades. The geographical haplotype structure exhibited by the Japanese populations is likely to have resulted from a series of allopatric differentiations with rapid range extensions of resultant lineages, leading to secondary contact or further admixture of mitochondrial haplotype clades and subclades. © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, 105 , 395–408.     

Lead poisoning in captive Andean condors (Vultur gryphus)

Elevated lead in the tissues of raptors, especially those that scavenge, is a common occurrence, and lead poisoning appears to be a significant problem in the ongoing recovery effort for California condors (Gymnogyps californianus). Elevated blood lead levels have been found in released birds, and a number of birds have died of lead poisoning. In earlier work, we dosed turkey vultures (Cathartes aura) with lead shot but found them to be a poor model for lead poisoning. In this study, we dosed four Andean condors (Vultur gryphus) with lead shot and found them to be quite sensitive, as two of the birds died and the other two exhibit signs of lead poisoning within 50 days. All lead-responsive parameters were affected, and regurgitation of dosed shot occurred only once. The response of the Andean condors appeared to mimic California condors, suggesting that once exposed to lead, the possibility of survival is poor. This is consistent with observations in the wild, where otherwise healthy birds exposed to metallic lead quickly succumb. At the very least, the release program has to maintain constant surveillance and an active lead monitoring program.     

Purification and characterization of a staphylolytic enzyme from Pseudomonas aeruginosa

A strain of Pseudomonas aeruginosa has been shown to produce an enzyme that lyses viable cells of Staphylococcus aureus. The maximal yield of the enzyme was obtained from shake flask cultures of P. aeruginosa which were grown for 18 to 22 hr at 37 C in Trypticase Soy Broth. A 333-fold purification of the enzyme was obtained by acetone precipitation of the culture liquor, followed by column chromatography on phosphonic acid cellulose and Bio-Gel P2. The staphylolytic enzyme exhibited maximal activity at 37 C in 0.01 m sodium phosphate (pH 8.5) and was stable at 37 C in the pH range of 7.5 to 9.5. The inhibition and stabilization of the enzyme by various organic and inorganic materials was investigated. Spheroplasts of S. aureus were formed by treating viable cells with the staphylolytic enzyme in 1 m sucrose or human serum.     

Construction of a chromosome map for the phage group II Staphylococcus aureus Ps55.

The genome size and a partial physical and genetic map have been defined for the phage group II Staphylococcus aureus Ps55. The genome size was estimated to be 2,771 kb by pulsed-field gel electrophoresis (PFGE) using the restriction enzymes SmaI, CspI, and SgrAI. The Ps55 chromosome map was constructed by transduction of auxotrophic and cryptic transposon insertions, with known genetic and physical locations in S. aureus NCTC 8325, into the Ps55 background. PFGE and DNA hybridization analysis were used to detect the location of the transposon in Ps55. Ps55 restriction fragments were then ordered on the basis of genetic conservation between the two strains. Cloned DNA probes containing the lactose operon (lac) and genes encoding staphylococcal protein A (spa), gamma hemolysin (hlg), and coagulase (coa) were also located on the map by PFGE and hybridization analysis. This methodology enabled a direct comparison of chromosomal organization between NCTC 8325 and Ps55 strains. The chromosome size, gene order, and some of the restriction sites are conserved between the two phage group strains.     

A Microscopic Characterization of the Infection of Green and Red Pepper Fruits by an Isolate of Colletotrichum gloeosporioides

Colletotrichum gloeosporioides is a common pathogenic fungus in many plants. To investigate the specificity of the isolate C. gloeosporioides to green fruits, fungal behaviours and anthracnose development on green and red pepper fruits were compared using light and stereo microscopic techniques. When the isolate of C. gloeosporioides was inoculated on both green and red fruits, conidial germination, appressoria, and infection hyphae were observed on both fruits within 24 h after inoculation. The fungal invasion and colonization continued to the epidermal cells of green fruits, but not to those of red ones. Initial anthracnose symptoms were detected only on green fruits at 2 days after inoculation resulting in typical sunken necrosis within 5 days after inoculation. Thus the specificity of the isolate to green fruits may be due to successful invasion and colonization of the infection hyphae from appressoria into the epidermal cells through epicuticular layers of green pepper fnats, but not on red ones.