Economic history of ostrich fern,Matteuccia struthiopteris,the edible fiddlehead

Although the ostrich fern, Matteuccia struthiopteris,is distributed throughout much of the Northern Hemisphere, its consumption as a spring vegetable has been largely restricted to the tables of the Maritime Provinces in Canada and neighboring Maine in the United States. However, in little more than a decade the demand has expanded beyond these traditional boundaries, due to the present availability of the frozen product. The heart of the industry is undoubtedly New Brunswick. The harvest of 200 t/yr is approximately 4 times that of Maine, and from an historical vantage the traditional use as a spring vegetable is with the New Brunswickers as well. In light of the present high demand for the product and the reports of localized overpicking, a review of the economic history, resource management and attempts at cultivation is presented.     

Application of the Indirect Immunoperoxidase Stain Technique to the Flagella of Azospirillum brasilense

An indirect immunoperoxidase stain was used to demonstrate by electron microscopy that an antigenic difference exists between the polar flagellum and the lateral flagella of Azospirillum brasilense ATCC 29145.     

Mapping of transfer RNA genes on tobacco chloroplast DNA

Tobacco chloroplast tRNAs have been purified by two-dimensional polyacrylamide gel electrophoresis, identified by aminoacylation, labelled at their 3-end and hybridized to tobacco chloroplast DNA restriction fragments, in order to establish a tRNA gene map. These hybridization studies have revealed the localization of at least seven genes in each inverted repeat region, a minimum of 22 tRNA genes in the large single copy region and one tRNA gene in the small single copy region. Comparison of the tobacco chloroplast tRNA gene map to that of maize shows many similarities, but also some differences suggesting that DNA sequence rearrangements have occurred in the chloroplast genome during evolution.     

A retroviral provirus closely associated with the Ren-2 gene of DBA/2 mice.

We have determined the entire nucleotide sequence of an intra-cisternal A particle (IAP) genome, associated with the Ren-2 gene of DBA/2 mice. This genome (MIARN) displays features common to other IAP retroviral-like genomes. Long terminal repeats (LTRs) are approximately 430 base pairs (bp) in length and show typical retroviral U3-R-U5 organisation, though the R-region, at 120 bp, is much larger than the average IAP. This difference probably arose by the amplification of a pyrimidine-rich sequence, by a slippage-mispairing mechanism. Flanking the 5' LTR is a sequence complementary to a phenylalanine tRNA, strongly conserved in all rodent IAP genomes and probably required to prime the initiation of (-) strand synthesis. Flanking the 3' LTR, is a purine-rich sequence probably required for (+) strand synthesis. The tRNA binding site (TBS) is flanked by six tandem copies of a sequence homologous to the TBS. The relationship of the MIARN element to other IAP genomes and the significance of its association with the highly expressed Ren-2 is discussed.     

Nucleotide sequence of the transposable element IS15

We have determined the complete nucleotide sequence of the right (R) copy of the insertion sequence IS15 which flanks, in direct orientation, the composite transposon Tn1525. IS15-R, which is capable of independent transposition, is 1648 bp long and has short (14 bp) perfect inverted repeats at its termini. Analysis of the nucleotide sequence indicates that IS15-R results from the transposition, in direct orientation, of a smaller (820 bp long) IS, designated IS15-Δ, into itself. This integration event is accompanied by the duplication of 8 bp in the target DNA. IS15-Δ possesses two large overlapping open reading frames (ORF) located on opposite strands. Because of this particular structure, IS15 possesses four large ORFs which, due to the integration event, exhibit some differences with those of the parental 1S15-Δ.     

The influence of early protein-calorie malnutrition on neuronal and glial protein synthesis

The effect of pre- and postnatal undernutrition, produced according to the method of Chow and Lee (3), on the rate of protein synthesis in the brains of rats 11, 21, 34 and 90 days of age was studied by measuring the incorporation ofl-[¹⁴C]valine in vivo andl-[³H]lysine in vitro. Both in vivo and in vitro experiments were performed with high concentration of the precursor to decrease the effects of pool variations and protein degradation. Particular interest was given to the effects of this form of early protein-calorie malnutrition (PCM) on neuronal and glial cells which were isolated from the brains by gradient centrifugation. Brain protein synthesis measured in vivo which showed a peak at 21 days in both animal series, was depressed by PCM at 11 days but stimulated at 34 days of animal age. Small effect was observed in the 90-day-old animals. A similar response as in whole brain was seen for neuronal cells, while glial cells showed a different reaction. Studies of in vitro protein synthesis did not reveal appreciable effects of undernutrition in whole brain. Both neuronal and glial cells showed a moderate but not statistically significant elevation of protein synthesis in animals subjected to early PCM.     

Morphometry and ultrastructure of prismatic cristae in mitochondria of a crayfish muscle. A hypothesis of the structural principle

Approximately 40% of the mitochondria in the sphincter muscle of the crayfish vas deferens have prismatic-type cristae. In cross section, the angular cristae have either triangular or rhomboid profiles which are surrounded by a hexagonal array of electron-dense dots. In longitudinal section, these mitochondria exhibit both thick and thin parallel lines, which represent cristae and filaments, respectively. It is postulated that the matrix of the prismatic-type mitochondria is packed with rodlets composed of an electron-dense core and a less dense shell. Close packing of these rodlets results in the regular hexagonal dot array. Deletion of fascicles of 3 or 4 rodlets results in spaces with triangular or rectangular cross sections. Lining of these spaces with membranes results in cristae with triangular or rhomboid cross sections.