Biochemical and serological evidence for an RNase E-like activity in halophilic Archaea.

Endoribonuclease RNase E appears to control the rate-limiting step that mediates the degradation of many mRNA species in bacteria. In this work, an RNase E-like activity in Archaea is described. An endoribonucleolytic activity from the extreme halophile Haloarcula marismortui showed the same RNA substrate specificity as the Escherichia coli RNase E and cross-reacted with a monoclonal antibody raised against E. coli RNase E. The archaeal RNase E activity was partially purified from the extreme halophilic cells and shown, contrary to the E. coli enzyme, to require a high salt concentration for cleavage specificity and stability. These data indicate that a halophilic RNA processing enzyme can specifically recognize and cleave mRNA from E. coli in an extremely salty environment (3 M KCI). Having recently been shown in mammalian cells (A. Wennborg, B. Sohlberg, D. Angerer, G. Klein, and A. von Gabain, Proc. Natl. Acad. Sci. USA 92:7322-7326, 1995), RNase E-like activity has now been identified in all three evolutionary domains: Archaea, Bacteria, and Eukarya. This strongly suggests that mRNA decay mechanisms are highly conserved despite quite different environmental conditions.     

Molecular cloning and functional expression of bacteriophage PK1E-encoded endoneuraminidase Endo NE

Homopolymeric α-2,8-linked sialic acid (PSA) has been found as a capsular component of sepsis- and meningitis-causing bacterial pathogens, and on eukaryotic cells as a post-translational modification of the neural cell adhesion molecule (NCAM). The polysaccharide is specifically recognized and degraded by a phage-encoded enzyme, the endo-N-acetylneuraminidase E (Endo NE). Endo NE therefore has become a valuable tool in the study of bacterial pathogenesis and eukaryotic morphogenesis. In this report we describe the molecular cloning of Endo NE and the expression of a functionally active recombinant enzyme. The cloned DNA sequence (2436 bp) encodes a polypeptide of 811 amino acids, which at the 5′ end contains a totally conserved neuraminidase motif. Expressed in Escherichia coli, the enzyme migrates as a single band of approximately 74 kDa in SDS-PAGE. A central domain of 669 amino acid residues is about 90% homologous to the recently cloned Endo NF. Both phage-induced lysis of bacteria and the catalysis of PSA degradation by the recombinant enzyme are efficiently inhibited by a polyclonal antiserum raised against the intact phage particle. The C-terminal region seems to be essential to enzymatic functions, as truncation of 32 amino acids outside the homology domain completely abolishes Endo NE activity. Our data also indicate that the 38 kDa protein, previously assumed to be a subunit of the Endo NE holoenzyme, is the product of a separate gene locus and is not necessary for in vitro depolymerase activity.     

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.     

Microscopic anatomy of the ovary ofAlouatta caraya

The microscopic structure of theAlouatta caraya ovary is studied in different ages and reproductive stages. The most significant feature seems to be the presence in adult ovaries of abundant glandular interstitial tissue which occupies both the cortex and medulla. It seems to be derived from the theca interna of atretic follicles. Discrete luteinized masses are present in the medulla in all the ovaries observed. Invaginations of the surface epithelium are seen only in infant and juvenile ovaries. The development of cystic follicles seems to be a common pathway of atresia.     

Measurement of serum amyloid A protein concentrations as test of renal allograft rejection in patients with initially non-functioning grafts.

Serum amyloid A protein concentrations were monitored in 10 renal transplant recipients who required dialysis after transplantation because of an initially non-functioning graft. Fifteen rejection episodes were identified by repeated fine needle aspiration biopsies of the grafts. All rejections were characterised by pronounced increases in serum amyloid A concentrations, the mean peak value being 363 (SE 57) mg/1 as compared with a mean preoperative concentration of 14 (5) mg/1. The rise in concentrations preceded the start of anti-rejection treatment by an average of 2.5 days in eight of the rejection episodes, in five episodes it occurred the same day, and in two episodes it occurred the next day. With exclusion of the predictable surgery induced rise in values, which peaked on the second postoperative day, there were 17 increases in amyloid A concentrations peaking at greater than or equal to 100 mg/1; in two cases they were not related to documented rejection. These findings show that measurements of serum amyloid A concentration provide a valuable non-invasive aid in identifying acute renal allograft rejection, including that in patients whose graft does not function initially.     

De novo trisomy 4pter→q21

Summary Clinical and cytogenetic findings in an infant girl with multiple congenital anomalies, principally anophthalmia, are presented. The patient's karyotype was 47,XX, +del(4)(pterq21), the largest partial trisomy of chromosome 4 reported. The possible mechanism of the origin of this abnormality is discussed.To whom offprint requests should be sent     

Translation and messenger RNA secondary structure

The possibility of translation being influenced by the messenger RNA secondary structure is investigated with the aid of a stochastic model. Simulations indicate that, at least for certain mRNA's, the mean ribosomal passage time decreases as the mean number of ribosomes on the messenger is increased. Furthermore, large variations in the passage times are found, in accordance with recent experimental results.