Observations on neurons and neuroglia from the area of the reticular formation in tissue culture

Summary The area of the reticular formation of the brain stem of several newborn and young manmals was cultivated in vitro. Neurons were observed for a period up to 54 days. At the end of this period in many preparations they still exhibited signs of chromatolysis as judged by the eccentric position of the nuclei and the peripheral location of the Nissl material. It has been impossible thus far to identify particular neurons as belonging to a particular nucleus of the reticular formation, probably due to slight morphological and structural changes of these cells in vitro. Although the oldest neurons observed were kept only 54 days in vitro it seems likely that they could have been maintained for a longer time since their appearance indicated more regenerative rather than degenerative features.Observations on the morphology and kinetics of glial and mesenchymal cells corroborated the findings of Pomerat and Costero (1956) and of Hild (1954, 1957a).This investigation was supported by a research grant (PHS B-364 [C4]) from the National Institute of Neurological Diseases and Blindness, of the National Institutes of Health, Public Health Service, administered by C. M. Pomerat.Fulbright and Smith-Mundt fellow.     

The phosphorylation of intramitochondrial AMP: A suggestion for the compartmentation of endogenous Pi pool

1. The mitochondrial level of AMP gradually diminishes during incubation of mitochondria with glutamate but does not with succinate. This decline of AMP, associated with stoichiometric increase in ADP and/or ATP, is accelerated by the addition of electron acceptors or 2,4-dinitrophenol, while arsenite, arsenate and rotenone are inhibitory. These results are in agreement with the view that AMP is phosphorylated to ADP in the inner space of rat liver mitochondria via succinyl-CoA synthetase (succinate: CoA ligase (GDP), EC 6.2.1.4) and GTP:AMP phosphotransferase dependent on the oxidation of 2-oxoglutarate, which is promoted by the transfer of electron from NADH to the respiratory chain.2. Studies of the periodical changes of chemical quantities of adenine nucleotides as well as of their labelling with ³²P_i reveals the following characteristics concerning mitochondrial phosphorylation. (i) In contrast to the mass action ratio of ATP to ADP, the ratio of ADP to AMP is not affected by the intramitochondrial concentration of P_i. (ii) ³²P_i, externally added, is incorporated into ADP much more slowly than into γ-phosphate of ATP. (iii) Conversely, ATP loses its radioactivity from γ-phosphate position more rapidly than [³²P]ADP when ³²P-labelled mitochondria are incubated with non-radioactive P_i.3. In order to elucidate the above characteristic properties of phosphorylation, a hypothetical scheme is proposed which postulates the two separate compartments in the intramitochondrial pool of P_i; one readily communicates with external P_i and is utilized for the phosphorylation of ADP in oxidative phosphorylation, while the other less readily communicates with external P_i and serves as the precursor of ADP via succinyl-CoA synthetase and GTP:AMP phosphotransferase.     

Genetic properties of arsenate sensitive mutants of Bacillus subtilis 168

Summary Arsenate sensitive mutants were isolated from Bacillus subtilis strain 168 after treatment with N-methyl-N-nitro-N-nitrosoguanidine or ethyl methane sulfonate. Though all mutants are phenotypically identical, a high proportion (40%) of the induced mutations are of a multisite nature as they do not revert spontaneously and are poorly transformable to arsenate resistance with wild type DNA. On the basis of transformation efficiency, UV inactivation kinetics and cotransduction frequency of outside markers, four independently isolated multisite arsenate sensitive mutations are characterized as resulting from large deletions of homogenous size (24000±6000 base pairs). The arsenate resistance locus was mapped between phe and aroD on the B. subtilis chromosome by PBS1 mediated transduction. Mechanisms for the formation of such chromosomal deletions are discussed.Part of the dissertation of Alice Adams Lindahl, presented to New York University in partial fulfillment of requirements for the Ph. D. degree. A preliminary report of this work was presented at the NATO International Symposium, Mol, Belgium, August 1970.     

Properties of flacherie virus of the silkworm, Bombyx mori

The flacherie virus of the silkworm, Bombyx mori, was isolated from infected larvae reared under aseptic conditions. Two types of infectious particles, tentatively designated FVS I and FVS II, were separated by density gradient centrifugation. Some properties of the separated particles were investigated. Electron micrographs showed that FVS I and FVS II were spherical particles with diameters of 27 ± 2 nm and 22 ± 2 nm, respectively. The sedimentation coefficients of FVS I and FVS II were 180 S and 134 S, respectively. It was concluded from experiments of incorporation of ³H-uracil inoculated into diseased larvae at late stage of flacherie disease that the nucleic acid of FVS II was RNA. The two types of particles were present in Sakaki and Wadayama strains of flacherie virus.     

Skipping flights in Ypthima butterflies (Lepidoptera: Nymphalidae)

The skipping flight patterns of three species of Ypthima (Lepidoptera: Nymphalidae) were analyzed using high‐speed video recordings to clarify how wings move and how driving forces are produced. All three species showed a flight pattern that includes a pause that accounts for about 50% of a flap cycle when their wings completely close after each upstroke. The observed pause causes the “skipping” flight trajectory based on the clap–fling mechanism. Pause duration was correlated with upstroke wing motion, suggesting the contribution of the latter to a long pause duration. This is also supported by the temporal relationship between the wing and body motions. The aerodynamic power necessary for the pause flight was calculated for the three species.     

New records of Gelidiella pannosa, Pterocladiella caerulescens and Pterocladiella caloglossoides (Rhodophyta, Gelidiales) from Japan

Three gelidialean species, Gelidiella pannosa (Feld‐mann) Feldmann et Hamel, Pterocladiella caerulescens (Kutzing) Santelices et Hommersand and Pterocladiella caloglossoides (Howe) Santelices, are newly reported from Japan, and their characteristic features are described. Monoecious plants of P. caerulescens produce spermatangial sori on: (i) fertile cystocarpic branchlets; (ii) special spermatangial branchlets on a cystocarpic axis; and (iii) branchlets of a special spermatangial axis. The latter two are newly reported in this species. Gelidiella pannosa has numerous unicellular independent points of attachment, whereas P. caerulescens and P. caloglossoides have the peg type of secondary rhizoidal anchorage. In the molecular phylogenetic study using small subunit ribosomal DNA sequences, G. pannosa is included in the Gelidiella clade with 100% bootstrap support in neighbor‐joining (NJ) analysis and 99% in maximum parsimony (MP) analysis. Pterocladiella caerulescens and P. caloglossoides are included in the Pterocladiella clade with 99.7% bootstrap support in NJ analysis and 100% in MP analysis. Each type of secondary rhizoidal attachment is completely consistent with the respective genus clade, which suggests that this morphological characteristic reflects phylogeny within the order Gelidiales.     

Two new species of Gelidium (Rhodophyta, Gelidiales), Gelidium tenuifolium and Gelidium koshikianum, from Japan

Two new marine red algae, Gelidium tenuifolium sp. nov. and Gelidium koshikianum sp. nov. (Gelidiales, Gelidiaceae) are described from Japan. Gelidium tenuifolium with large‐sized thalli (up to 30 cm tall) is distinguished from other species with such thalIi by the production of wide, flattened and thin branches (up to 2 mm wide and 60–80 urn thick), the presence of an apical depression and simple determinate branches. Gelidium koshikianum with middle‐sized thalli (5–8 cm tall) is distinguished from other species with such thalli by having wide axes (up to 2.5 mm wide) and short (2.0–3.2 mm), unbranched, second‐ and third‐order branches issuing at short intervals (0.8–1.4 mm). In phylogenetic analyses of rbcL sequences, four Gelidium species that are chiefly distributed in Japan including G. tenuifolium were clustered together with 99% bootstrap value (Japanese Gelidium‐complex clade). Gelidium linoides Kützing came to the position of the sister group to G. tenuifolium with 99% bootstrap value. There were four substitutions (0.3% divergence) between G. linoides and G. tenuifolium sequences. Gelidium koshikianum and Gelidium allanii Chapman were clustered together with 100% bootstrap value and they came to the position of the sister group to the Japanese GeIidium‐complex clade with 83% bootstrap value. There were six substitutions (0.4% divergence) between G. koshikianum and G. allanii sequences.     

An antimycobacterial pleuromutilin analogue effective against dormant bacilli

Pleuromutilin is a promising pharmacophore to design new antibacterial agents for Gram-positive bacteria. However, there are limited studies on the development of pleuromutilin analogues that inhibit growth of Mycobacterium tuberculosis (Mtb). In screening of our library of pleuromutilin derivatives, UT-800 (1) was identified to kill replicating- and non-replicating Mtb with the MIC values of 0.83 and 1.20?μg/mL, respectively. UT-800 also kills intracellular Mtb faster than rifampicin at 2× MIC concentrations. Pharmacokinetic studies indicate that 1 has an oral bioavailability with an average F-value of 27.6%. Pleuromutilin may have the potential to be developed into an orally administered anti-TB drug.