Decreased production ofpara-hydroxypenicillin V in penicillin V fermentations

Summary Penicillin V (phenoxymethyl penicillin) is produced by industrial strains ofPenicillium chrysogenum in the presence of phenoxyacetic acid (POAc), a side-chain precursor for the penicillin V molecule. The wild-type strain ofP. chrysogenum produces an undesirable penicillin byproduct,para-hydroxypenicillin V (p-OH penicillin V), in addition to penicillin V, viapara-hydroxylation of POAc and subsequent incorporation of thep-OH phenoxyacetic acid into the penicillin molecule. Most of thep-OH penicillin V is produced late in cycle when the POAc concentration in the medium is nearly depleted. The level ofp-OH penicillin V produced by the control strain ranges up to 10–15% of the total penicillins produced. 3-Phenoxypropionic acid andp-bromophenylacetic acid partially inhibit the formation ofp-OH penicillin V with a minimal effect on penicillin V productivity. Mutants deficient in their ability to hydroxylate POAc were found to produce lower levels ofp-OH penicillin V. Multi-step mutation and screening, starting with the wild-type strain, have culminated in isolation of mutants which producep-OH penicillin V as 1% of the total penicillins with no adverse effect on penicillin V productivity.     

CYTOGEOGRAPHIC STUDIES ON NORTH AMERICAN ASTERS. I. RANGE SURVEYS OF VIRGULUS ADNATUS,V. CONCOLOR,V. GEORGIANUS,V. GRANDIFLORUS,V. NOVAE-ANGLIAE,V. OBLONGIFOLIUS,V. PATENS,AND V. WALTERI

Chromosome number determinations from 118 populations of eight species of the aster genus Virgulus are reported for the first time. Based on these counts and literature reports the geographic distributions of diploids and tetraploids in V. concolor, V. novae-angliae, V. oblongifolius, and V. patens have been determined. In the first three species, diploids were widely distributed, while tetraploids were more restricted. In V. patens, diploids were restricted to the southwestern portion of the species’ range, while tetraploids were found throughout the range. Both V. adnatus and V. walteri were found only at the tetraploid level throughout their ranges. Two other species with restricted distributions were consistently found to be high level polyploids: V. georgianus with 2n = 50, V. grandiflorus with 2n = 60. The following new combinations are listed: Virgulus georgianus (Alexander ex Small) Semple; Virgulus subsect. Brachyphylli (Torr. & Gray) Semple; and Virgulus sect. Polyliguli (Semple & Brouillet) Semple.     

Callus induction from protoplasts of V. unguiculata,V. sublobata and V. mungo

Summary Protoplasts were isolated from hypocotyl of V. mungo (L.) Hepper or hypocotyl-derived callus of V. sublobata (Phaseolus sublobata Roxb.) and V. unguiculata (L.) Walp (syn. V. sinensis (L.) Saviex Hassk) using an enzyme solution comprising Cellulase 2.5%, Macerozyme, Hemicellulase and Driselase each at a 0.5% level in 0.5 M sorbitol. Isolated protoplasts were cultured in Murashige and Skoog's (1962) basal liquid medium supplemented with BA, NAA, 2,4-D (1 mg/l each) and sucrose (14%). After four weeks, protoplast colonies were transferred to the same medium with a reduced level of sucrose (7%). Colonies proliferated into actively growing calli. Further attempts to regenerate plants from such calli were not successful. However, protoclones of V. unguiculata differentiated roots on auxin/cytokinin supplemented media. Alternative methods for shoot differentiation from protoplastderived cultures were tried by the use of Agrobacterium tumefaciens shooter strains pGV 2215 or pGV 2298 or wild type strain B6S3.     

Roshchina, V.V. Neurotransmitters in plant life

The prevailing common knowledge says that animals, and especiallymammals, use hormones to coordinate biochemical activities ofdifferent types of cells, while neuromediators serve as signallingmolecules for communication within the animal’s body andwith the outside world. On the other hand, higher plants utilizehormone-like substances to coordinate their growth and development,but they lack the sophisticated systems for integrative processingand exchange of information. Is it true or false? This book by     

Coagulation factor V

The coagulation cascade involves sequential enzymatic activations of serine protease zymogens that converge on the generation of thrombin. Factor V (FV) takes part in this process as a component of the prothrombinase complex. Besides its role as procoagulant factor, it is also involved in the physiologic anticoagulant pathway, by participating in the inactivation of activated factor VIII (FVIIIa). Given the dual role of FV, genetic defects in FV gene may result in opposite hemorrhagic or thrombotic phenotypes. This review focuses on the structure, function (procoagulant and anticoagulant), regulation (activation and inactivation) of FV as well as on the genetic defects associated with mutations in the FV gene.