Effect of environmental phosphate concentration on protein export by Bacillus licheniformis NCIB 6346

Bacillus licheniformis NCIB 6346 was grown under phosphate or magnesium limitation in continuous culture and forward and reverse transitions carried out to examine their effects upon extracellular enzyme production. Analysis of the observed kinetics allowed a distinction to be made between the effects of phenotypic variation and of genetic selection upon exoenzyme production. Furthermore, increases in the phosphate concentration (0.3–30 mM) were directly related to increased phenotypic expression of alpha-amylase. By contrast, penicillinase production was reduced under these conditions but analysis revealed that its phenotypic expression was only indirectly influenced by the concentrations of either magnesium or phosphate present during the transitions.     

Inhibiteurs non acides et dormance embryonnaire chez Taxus baccata

Non-acidic inhibitors and embryo dormancy in Taxus baccata L. Embryo dormancy of Taxus baccata is eliminated when the embryos are continuously kept in sterile nutritive liquid medium. After 3 weeks of culture, an important non-acidic inhibitory complex can be extracted from this liquid medium. At least three substances are involved: two pigments and a compound with some properties that suggest xanthoxin. These substances are neither found in embryos taken directly from the seeds, nor in liquid medium after 8 days of culture, which is the time necessary and sufficient to allow germination after transfer on agar medium. Such behaviour is quite different from that of ABA previously studied and indicates that these non-acidic inhibitors appear late during the culture and are not directly involved in embryo dormancy.     

The evolution of myrmicine ants: phylogeny and biogeography of a hyperdiverse ant clade (Hymenoptera: Formicidae)

This study investigates the evolutionary history of a hyperdiverse clade, the ant subfamily Myrmicinae (Hymenoptera: Formicidae), based on analyses of a data matrix comprising 251 species and 11 nuclear gene fragments. Under both maximum likelihood and Bayesian methods of inference, we recover a robust phylogeny that reveals six major clades of Myrmicinae, here treated as newly defined tribes and occurring as a pectinate series: Myrmicini, Pogonomyrmecini trib.n. , Stenammini, Solenopsidini, Attini and Crematogastrini. Because we condense the former 25 myrmicine tribes into a new six‐tribe scheme, membership in some tribes is now notably different, especially regarding Attini. We demonstrate that the monotypic genus Ankylomyrma is neither in the Myrmicinae nor even a member of the more inclusive formicoid clade—rather it is a poneroid ant, sister to the genus Tatuidris (Agroecomyrmecinae). Several species‐rich myrmicine genera are shown to be nonmonophyletic, including Pogonomyrmex, Aphaenogaster, Messor, Monomorium, Pheidole, Temnothorax and Tetramorium. We propose a number of generic synonymies to partially alleviate these problems (senior synonym listed first): Pheidole = Anisopheidole syn.n. = Machomyrma syn.n. ; Temnothorax = Chalepoxenus syn.n. = Myrmoxenus syn.n. = Protomognathus syn.n. ; Tetramorium = Rhoptromyrmex syn.n. = Anergates syn.n. = Teleutomyrmex syn.n. The genus Veromessor stat.r. is resurrected for the New World species previously placed in Messor; Syllophopsis stat.r. is resurrected from synonymy under Monomorium to contain the species in the hildebrandti group; Trichomyrmex stat.r. is resurrected from synonymy under Monomorium to contain the species in the scabriceps‐ and destructor‐groups; and the monotypic genus Epelysidris stat.r. is reinstated for Monomorium brocha. Bayesian divergence dating indicates that the crown group Myrmicinae originated about 98.6 Ma (95% highest probability density 87.9–109.6 Ma) but the six major clades are considerably younger, with age estimates ranging from 52.3 to 71.1 Ma. Although these and other suprageneric taxa arose mostly in the middle Eocene or earlier, a number of prominent, species‐rich genera, such as Pheidole, Cephalotes, Strumigenys, Crematogaster and Tetramorium, have estimated crown group origins in the late Eocene or Oligocene. Most myrmicine species diversity resides in the two sister clades, Attini and Crematogastrini, which are estimated to have originated and diversified extensively in the Neotropics and Paleotropics, respectively. The newly circumscribed Myrmicini is Holarctic in distribution, and ancestral range estimation suggests a Nearctic origin. The Pogonomyrmecini and Solenopsidini are reconstructed as being Neotropical in origin, but they have subsequently colonized the Nearctic region (Pogonomyrmecini) and many parts of the Old World as well as the Nearctic region (Solenopsidini), respectively. The Stenammini have flourished primarily in the northern hemisphere, and are most likely of Nearctic origin, but selected lineages have dispersed to the northern Neotropics and the Paleotropics. Thus the evolutionary history of the Myrmicinae has played out on a global stage over the last 100 Ma, with no single region being the principal generator of species diversity. This published work has been registered in ZooBank, http://zoobank.org/urn:lsid:zoobank.org:pub: BB6829C4‐DA79‐45FE‐979E‐9749E237590E .     

The effect of ionophores on growth and glycosyltransferase production of Streptococcus sanguis

Abstract Batch cultures of Streptococcus sanguis NCTC7865 were grown in complex medium in the presence and absence of the ionophores gramicidin, valinomycin and nigericin, to study their effects on growth and glycosyltransferase production. Growth of S. sanguis was markedly inhibited by nigericin or gramicidin, whereas valinomycin had no significant effect. The presence of ionophores caused only slight decreases in glucosyltransferase activity. Fructosyltransferase activity was however reduced by at least 90%. The results indicate that ΔpH rather than ΔΨ is essential for maintaining normal growth in S. sanguis . However, both ΔpH and ΔΨ are necessary for fructosyltransferase synthesis and secretion, but are not apparently involved in the synthesis and secretion of glucosyltransferase.     

Veneers and plywood—their manufacture and use

Two closely related industries that depend, to a major degree, upon domestic sources of red gum, Douglasfir, black walnut, red and white oaks, sugar maple, Sitka spruce, Ponderosa pine and Port Orford cedar; and upon foreign sources of mahogany, rosewood, zebrawood, avodiré, bossé, ebony and other exotic species.     

c-AMP and Morphogenesis of Acetabularia

The c-AMP content has been found to double when Acetabularia develop from 5–10 mm long to grown or almost full-grown algae.
The biological significance of this fact has been approached by studying the effects of drugs known to influence the intracellular c-AMP content on the development of Acetabularia. When grown in the presence of theophyllin or papaverin, inhibitors of phosphodiesterase, the Acetabularia display a striking response during the exponential growth period; the final length, however, is not affected. Both substances increase the c-AMP content of the algea. Isoproterenol, which activates adenylate cyclase in many systems, also influences Acetabularia during the exponential growth period and, in addition, slightly affects cap formation.
The change in c-AMP content in the course of development and the effects of drugs influencing (theophyllin and papaverin) or likely to influence (isoproterenol) the c-AMP content of the algae suggest that this nucleotide plays a role at the time of intense growth.
The same phosphodiesterase activity has been found in the 5–10 mm and the 19–25 mm long algae, whereas two enzymes were found in cap-bearing Acetabularia.
The results are discussed as well as the involvement of c-AMP in the development of this alga.