Herbicidins A and B, two new antibiotics with herbicidal activity. I. Producing organism and biological activities

Herbicidins A and B, two new antibiotics with selective and contact herbicidal activity, were produced by a new species of Streptomyces designated as S. sagononensis. Among tested microorganisms, herbicidins indicated some activity against fungi in vitro and Xanthomonas oryzae in vivo. Their characteristic features were brought into relief by their selective and contact killing effect on many dicotyledonous plant as well as their inhibition of germination of the plant seeds, such as Chinese cabbage.     

Thiazohalostatin, a new cytoprotective substance produced by Actinomadura. I. Taxonomy, production, isolation and biological activities

Thiazohalostatin has been isolated from the culture broth of Actinomadura sp. by a screening program designed to find novel cytoprotective substances. It was purified by use of column chromatography on silica gel, reversed phase HPLC and then isolated as colorless powder. Thiazohalostatin prevented cell death caused by calcium overload and exhibited an inhibitory activity against lipid peroxidation.     

Effect of solar activity on the physiological rhythms of biological systems

The infradian components, including those with a period of about 3.5, 7, 30 days, are ubiquitously found in biology, from unicells to complex biological organisms. It can be hypothesized that heliogeophysical factors other than the solar visible light, likely at the origin of the circadian system (with a period of about 24 hours), may be responsible for the infradian biosystems.     

Studies on the biological effects of deuteriated organic compounds. I. Antifungal activity of perdeuteriated fatty acids on dermatophytes in vitro

The antifugal activity of some perdeuteriated fatty acids, with normal chain 11 to 18 carbon atoms, was investigated on common dermatophytes Epidermophyton floccosum, Microsporum canis, Trichophyton mentagrophytes and T. rubrum under in vitro conditions. These studies were performed by dilution technique and with respiratory measurements, Perdeuteriation of some fatty acids increases their inhibitory effect on the dermatophyte growth. Perdeuteriated n-hendecanoic acid proved to be the most active of the substances tested. Possible mechanisms behind the enhanced antifungal activity due to the perdeuteriation of fatty acids are discussed.     

Antigenic activity of angiotensin II and its fragments

The antigenic activity of angiotensin and its seven fragments has been studied in cross-reaction with specific antibodies, elicited to angiotensin and its fragments: C-terminal hexapeptide and middle tetrapeptide. It has been found that all the fragments studied possess certain affinity for antibodies elicited to angiotensin, C-terminal hexapeptide and middle tetrapeptide. The middle tetrapeptide was identified to be the immunologically active centre of the angiotensin molecule.     

Potentiation of latent inhibition.

Rats were given exposure either to an odor (almond) or a compound of odor plus taste (almond plus saline), prior to training in which the odor served as the conditioned stimulus. It was found, for both appetitive and aversive procedures, that conditioning was retarded by preexposure (a latent inhibition effect), and the extent of the retardation was greater in rats preexposed to the compound (i.e., latent inhibition to the odor was potentiated by the presence of the taste). In contrast, the presence of the taste during conditioning itself overshadowed learning about the odor. We argue that the presence of the salient taste in compound with the odor enhances the rate of associative learning, producing a rapid loss in the associability of the odor. This loss of associability will generate both overshadowing and the potentiation of latent inhibition that is observed after preexposure to the compound. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

mRNA decapping activities and their biological roles

The 5' cap structure of eukaryotic mRNAs is significant for a variety of cellular events and also serves to protect mRNAs from premature degradation. Analysis of mRNA decay in Saccharomyces cerevisiae has shown that removal of the 5' cap structure is a key step in the turnover of many yeast mRNAs, and that this decapping is carried out by Dcp1p. In addition to the yeast decapping enzyme, other activities that can cleave the 5' cap structure have been described. These include two mammalian enzymes and two viral activities that cleave cellular mRNA cap structures as part of their life cycle. Here we review these various decapping activities and discuss their biological roles.     

Kanchanamycins, new polyol macrolide antibiotics produced by Streptomyces olivaceus Tü 4018. I. Taxonomy, fermentation, isolation and biological activities

The kanchanamycins, a group of novel 36-membered polyol macrolide antibiotics were detected in the culture filtrate and mycelium of Streptomyces olivaceus Tü 4018 by HPLC-diode-array and HPLC-electrospray-mass-spectrometry screening. The compounds show antibacterial and antifungal activities, and are especially effective against Pseudomonas fluorescens. Besides the kanchanamycin complex, strain Tü 4018 produces the 42-membered macrolactones, oasomycin A and desertomycin A, as well as tryptophan-dehydrobutyrine diketopiperazine and daidzein.     

Effect of insulin on the phospholipase-D activity of untreated and insulin-pretreated (hormonally imprinted) Tetrahymena

Insulin treatment of the unicellular Tetrahymena enormously increases the activity of phospholipase D (PLD) within 30 min. Insulin pretreatment (hormonal imprinting) does not influence basal PLD activity after 24 h. The second insulin treatment failed to stimulate PLD activity in insulin imprinted Tetrahymena. The results suggest the presence of the functional PLD activity in Tetrahymena and that hormonal imprinting modifies signal transduction to PLD, as previously reported in calmodulin activation and phophatidylinositol 4,5-bis-phosphate (PIP2) synthesis.     

PC-766B, a new macrolide antibiotic produced by Nocardia brasiliensis. I. Taxonomy, fermentation and biological activity

An actinomycete strain SC-4710, a new soil isolate, was found to produce a new macrolide antibiotic, PC-766B. Chemotaxonomic analysis of the producing organism revealed that the cells of SC-4710 had type IV cell wall, type A whole cell sugar pattern, type PII phospholipids, menaquinone MK-8(H4), cellular fatty acids comprising straight-chain saturated, unsaturated and tuberculostearic acids, and mycolic acids. The strain was identified as Nocardia brasiliensis (Lindenberg) Pinoy. The antibiotic, PC-766B, was active against Gram-positive bacteria, and some fungi and yeasts, but inactive against Gram-negative bacteria. It also showed antitumor activity against murine tumor cells in vitro and in vivo, and a weak inhibitory activity against Na+, K(+)-ATPase in vitro.     

Calbistrins, novel antifungal agents produced by Penicillium restrictum. I. Production, taxonomy of the producing organism and biological activity

Over a 14-year period, from 1971 to 1985, there were 15 patients referred to the Princess Margaret Hospital in Toronto for postoperative radiotherapy to the cervical lymph nodes following radical neck surgery for metastatic cancer. An intensive investigation failed to yield a primary site in any patient. All of the patients had extensive neck disease with significant indications for postoperative radiotherapy (massive neck nodes, invasion of extra nodal structures or fixation to unresectable adjacent structures). Of this highly selected group of patients with advanced neck disease: 4/15 (27%) died within one year of uncontrolled local disease, a further 2/15 (13%) died within four years of metastatic/recurrent disease, 6/15 (33%) died of intercurrent disease and 3/15 (20%) were alive with at least four years follow-up. Although all patients presented with advanced disease, survival and significant palliation was possible in this select group of patients.     

Immunosuppressive activity of C-terminal fragments of tachykinins

60 eyes of 60 cases with complicated retinal detachment were treated by vitrectomy combined with silicone oil tamponade, including grade D of proliferative vitreoretinopathy (PVR) in 27, giant retinal tears with posterior flaps folded up in 15, posterior polar or macular holes in 13 and traumatic PVR in 5 eyes. After 3-24 months of follow-up, it is shown that 48 eyes obtained anatomic reattachment, the success rate being 80%, and the post-operative visual acuities improved in 43 eyes of which 32 eyes achieved > 0.05. The authors consider that vitrectomy and membrane peeling create a situation for silicone oil tamponade to play its role fully, vitrectomy is perfected by the combination of silicone oil tamponade and the rate of success of the retinal detachment operation is increased. The theory, indications, advantages and disadvantages of silicone oil tamponade were briefly discussed.     

Studies on delayed-type hypersensitivity to hen egg-white lysozyme. I. Peptide fragments of lysozyme inducing delayed-type hypersensitivity

Eleven peaks were separated by Carboxymethyl-cellulose column chromatography of peptic digest of lysozyme. Being stronger in antigenic activity two peaks of them, P-3 and P-9, were selected and purified further respectively by Amberlite IRC-50 and Sephadex G-50 column chromatography. As the results, PP-3 and PP-9 were obtained each as a single peak. For estimation of their capacities to induce delayed-type hypersensitivity, the antigen-induced 3H-thymidine incorporation, the migration inhibition of peritoneal cells and the delayed-type skin reaction were tested in guinea pigs immunized with native lysozyme or any of its fractions. PP-9 was almost as active as intact lysozyme in these capacities. On the other hand, PP-3 showed a slight inhibition of migration of peritoneal cells and no stimulation of 3H-thymidine incorporation into the lymph node cells. Moreover, the delayed-type skin reaction elicited by PP-3 was always weaker than that elicited by PP-9. Guinea pigs immunized with either PP-3 or PP-9 were also tested for these reactions. PP-9 and native lysozyme elicited these reactions in guinea pigs immunized with PP-9, but PP-3 did not. On the other hand, PP-3 and lysozyme elicited these reactions in those immunized with PP-3, but PP-9 did not. The possibility of recognition of two functionally different areas, one for production of the circulating antibody and the other for induction of delayed-type hypersensitivity, on the lysozyme molecule was discussed.     

Potentiation of pirarubicin activity in multidrug resistant cells by rifampicin

The effect of the anti-tuberculosis drug rifampicin on pirarubicin activity was investigated in multidrug-resistant cells overexpressing P-glycoprotein. Rifampicin increased the sensitivity of pirarubicin to anthracycline-resistant mouse leukemic P388 cells and significantly enhanced the cytotoxicity and intracellular accumulation of pirarubicin in resistant cells, but had no effect in parent cells. By contrast, two other rifamycins, rifamycin B and SV, had no effect on pirarubicin accumulation in resistant cells. Rifampicin also enhanced pirarubicin-induced apoptosis and G2/M blockade on the cell cycle in resistant cells. These results show that rifampicin enhances the cytotoxic action of pirarubicin in resistant cells, at least partly via the inhibition of cellular pirarubicin efflux.     

Latex immunoassays: comparative studies on covalent and physical immobilization of antibodies. I. F(ab')2 fragments

Colloidal particles coated with antibodies are currently used in diagnostic test systems for the detection of antigens in biological fluids. Immobilization is usually carried out by physical adsorption. Covalent coupling of antibodies to particles, however, offers certain advantages. The present research deals with the study of these possible advantages. A sulphonated polystyrene latex has been used to prepare an immunolatex with physically adsorbed antibodies, while a functionalized latex with chloromethyl groups on the surface has been used for the partly covalent coupling of the antibody (F(ab')2 fragments). The immunoreactivity was studied by measuring the variations in scattered light intensity after mixing a solution of CRP antigen and the sensitized latex. The influence on the immunoresponse of the scattering angle (5, 10, and 20 deg), protein coverage and storage time have been studied for both systems.     

Effect of Wuchereria bancrofti (Cobbold infection on the biological activities of Culex pipiens L. (Diptera: Culicidae) in Egypt

The impact of moderate infection with Wuchereria bancrofti (Cobbold) (25 mf/50 microliters blood) on the biological activities of Culex pipiens L. were investigated. Data revealed that W. bancrofti parasites did not interfere significantly with the oviposition rate (81.97%, 80.228% in non-infected and infected mosquitoes, respectively), fecundity (73.56 +/- 4.56 and 74.23 +/- 5.05 eggs/female) duration of the gonotrophic cycle (6.34 +/- 0.29 and 6.05 +/- 0.26 days), or egg hatchability (88.06% and 90.07%) of infected mosquitoes. Furthermore adult survival to the extrinsic incubation period of infected females (91.8%), did not vary from that of non-infected ones (78.87%). It is suggested that the lack of variations is due to the relatively low level of microfilariae (mf) to which mosquitoes are generally exposed, as revealed by parasite burden. It is concluded that in Egypt the relationship of W. bancrofti to Cx. pipiens is that of a commensal rather than a parasite.     

MR566A and MR566B, new melanin synthesis inhibitors produced by Trichoderma harzianum. I. Taxonomy, fermentation, isolation and biological activities

Epitestosterone, a C19-steroid with anti-androgenic activity, was determined in the plasma of 234 boys and men from the ages of 6-86 years, and in the prostate tissue of 15 men 55-82 years of age. It was documented that, while in adulthood the concentration of epitestosterone is about ten times lower than the concentration of testosterone, in the pre-pubertal period the level of epitestosterone is similar or even higher than that of testosterone. In the hyperplastic prostate tissue the content of epitestosterone is comparable to that of androstenedione, it is about twice as high as the content of testosterone and approximately half that of the content of dihydrotestosterone. At least in the case of pre-pubertal boys and in the prostatic tissue it is therefore possible to include epitestosterone into consideration as a regulatory factor for the androgen-dependent events.