Active specific immunotherapy of guinea pigs with visceral tumor implants

Summary Guinea pigs, each with established, 7-day-old, syngeneic visceral micrometastases of line 10 tumor implanted intravenously, were immunized by intradermal inoculations into several sites of a mixture of irradiated line 10 cells and an emulsion containing heat-killed BCG or Mycobacterium phlei bacilli. This treatment led to survival of 72 of 80 treated animals (90%). Therapeutic effectiveness depended on the dose of mycobacteria and on that of irradiated tumor cells. Animals treated by intradermal injection of mycobacteria attached to oil droplets alone or with irradiated tumor cells alone, all died with multiple foci of pulmonary tumor.     

Kv1.3 voltage-gated potassium channels link cellular respiration to proliferation through a non-conducting mechanism

Cellular energy metabolism is fundamental for all biological functions. Cellular proliferation requires extensive metabolic reprogramming and has a high energy demand. The Kv1.3 voltage-gated potassium channel drives cellular proliferation. Kv1.3 channels localise to mitochondria. Using high-resolution respirometry, we show Kv1.3 channels increase oxidative phosphorylation, independently of redox balance, mitochondrial membrane potential or calcium signalling. Kv1.3-induced respiration increased reactive oxygen species production. Reducing reactive oxygen concentrations inhibited Kv1.3-induced proliferation. Selective Kv1.3 mutation identified that channel-induced respiration required an intact voltage sensor and C-terminal ERK1/2 phosphorylation site, but is channel pore independent. We show Kv1.3 channels regulate respiration through a non-conducting mechanism to generate reactive oxygen species which drive proliferation. This study identifies a Kv1.3-mediated mechanism underlying the metabolic regulation of proliferation, which may provide a therapeutic target for diseases characterised by dysfunctional proliferation and cell growth.Subject terms: Cell growth, Energy metabolism     

In vitro propagation of shoot buds of Carica papaya L. (caricaceae) var. Honey Dew

Shoot buds from the saplings and the fruit bearing plants of Carica papaya L.. var. Honey Dew (papaya) initially treated with Gentamycin were cultured in modified MS media, each with a different hormonal combination, for the establishment of cultures and multiplication and rooting of plants. About 43% of explants from fruit bearing plants and 69% of those from saplings remained free of contamination and retained regeneration capacity when treated in 500 mg/l Gentamycin. For the establishment of the explants a medium containing 1 mg/l GA₃ and 2 mg/l kinetin was necessary. When established buds were transferred to medium containing 1 mg/l NAA and 3 mg/l kinetin, calli were initiated at cut ends of shoot buds; multiplication started on transfer to NAA (0.1 mg/l) and BAP (0.5 mg/l) medium. Cultures have been maintained for the last twenty months without any loss in multiplication rate. Rooting was induced in medium with reduced salt concentration containing 2 mg/l IBA. Shoot elongation was induced after prolonged culture in the same rooting medium.Abbreviations MS Murashige and Skoog, 1962 - SH Schenk and Hildebrandt, 1972 - GA₃ Gibberellic acid - Kn Kinetin - NAA Napthaleneacetic acid - BAP 6 -Benzylaminopurine - IBA Indole-3-butyric acid - IAA Indole-3-acetic acid     

Pulmonary metastases in guinea pigs as a consequence of dermal implantation of line-10 tumor cells

Summary Metastases to the lungs of guinea pigs occurred at high frequency as a consequence of intradermal implantation of tumor cells derived from the syngeneic hepatocellular carcinoma line-10. Surgery had a major influence on the proportion of guinea pigs found to have pulmonary metastases at necropsy. Without surgery all guinea pigs died with extensive lymph node metastases; macroscopic pulmonary metastases were present in a minority of the animals. Animals treated by excision of dermal tumors survived longer than untreated animals, and macroscopic pulmonary metastases were present in the majority of the animals. Animals treated by excision of dermal tumor and regional lymph nodes were rendered tumor-free. The data suggest that lymph node metastases were the most likely source of the tumor cells that spread to the lungs in animals from whom the dermal tumor transplant had been removed.     

Molecular aggregation of nucleotides and carbohydrates—their implication to prebiotic polymerization

Hydrogen bonding pattern of nucleotides and carbohydrates has been analysed using Cambridge database. An analysis on ribonucleotides shows the 3′ …5′ hydrogen bond mediated aggregation to be the most common alignment. The 2′ …5′ alignment, which occurs under special circumstances in nature, is found to be the second choice. An analysis on carbohydrates suggests that self assembly of these molecules is not conducive to the formation of polysaccharides of the type which are found in present day living organisms. Further, the role of water molecules in the polymerization of three important biomolecules, namely nucleotides, carbohydrates and amino acids, has been analysed. Implication of these results to prebiotic polymerization is discussed DCB contribution No. 804.     

Who really ate the fruit? A novel approach to camera trapping for quantifying frugivory by ruminants

Tropical forest ruminants disperse several plants; yet, their effectiveness as seed dispersers is not systematically quantified. Information on frequency and extent of frugivory by ruminants is lacking. Techniques such as tree watches or fruit traps adapted from avian frugivore studies are not suitable to study terrestrial frugivores, and conventional camera traps provide little quantitative information. We used a novel time-delay camera-trap technique to assess the effectiveness of ruminants as seed dispersers for Phyllanthus emblica at Mudumalai, southern India. After being triggered by animal movement, cameras were programmed to take pictures every 2 min for the next 6 min, yielding a sequence of four pictures. Actual frugivores were differentiated from mere visitors, who did not consume fruit, by comparing the number of fruit remaining across the time-delay photograph sequence. During a 2-year study using this technique, we found that six terrestrial mammals consumed fallen P. emblica fruit. Additionally, seven mammals and one bird species visited fruiting trees but did not consume fallen fruit. Two ruminants, the Indian chevrotain Moschiola indica and chital Axis axis, were P. emblica’s most frequent frugivores and they accounted for over 95% of fruit removal, while murid rodents accounted for less than 1%. Plants like P. emblica that are dispersed mainly by large mammalian frugivores are likely to have limited ability to migrate across fragmented landscapes in response to rapidly changing climates. We hope that more quantitative information on ruminant frugivory will become available with a wider application of our time-delay camera-trap technique.     

Stereochemistry of peptides containing 1-aminocycloheptane-1-carboxylic acid (Ac7c).

The crystal structures of four peptides incorporating 1-aminocycloheptane-1-carboxylic acid (Ac7c) are described. Boc-Aib-Ac7c-NHMe and Boc-Pro-Ac7c-Ala-OMe adopt beta-turn conformations stabilized by an intramolecular 4----1 hydrogen bond, the former folding into a type-I/III beta-turn and the latter into a type-II beta-turn. In the dipeptide esters, Boc-Aib-Ac7c-OMe and Boc-Pro-Ac7c-OMe, the Ac7c and Aib residues adopt helical conformations, while the Pro residue remains semi-extended in both the molecules of Boc-Pro-Ac7c-OMe found in the asymmetric unit. The cycloheptane ring of Ac7c residues adopts a twist-chair conformation in all the peptides studied. 1H-NMR studies in CDCl3 and (CD3)2SO and IR studies in CDCl3 suggest that Boc-Aib-Ac7c-NHMe and Boc-Pro-Ac7c-Ala-OMe maintain the beta-turn conformations in solution.