Charactererization of novel non-toxic Bacillus thuringiensis isoloates from Korea

J.Y. ROH, H.W. PARK, B.R. JIN, H.S. KIM, Y.M. YU AND S.K. KANG. 1996. Four Bacillus thuringiensis isolates from soil samples produced parasporal inclusions which were non-toxic to insects. The isolates were named B. thuringiensis NTB-1, NTB-2, NTB-3 and NTB-4. The parasporal inclusions were shown to be ovoid by phase contrast and scanning electron microscopy. The serotypes of the four isolates were determined by agglutination using 33 antisera; NTB-1 and NTB-4 seemed to be subsp. isruelensis ,and NTB-2 seemed to be subsp. pondzcheriensis . NTB-3 did not react with the 33 antisera. However, comparison of parasporal protein and plasmid DNA patterns of the four isolates with those of 15 known non-toxic B. thuringiensis strains demonstrated that the four isolates are novel.     

Effect of soybean oil on the enhanced expression of hirudin gene in Hansenula polymorpha

Summary A heterologous gene from bloodsucking leech for anticoagulant, hirudin, has been expressed in the methylotrophic yeast Hansenula polymorpha. The addition of 1%(v/v) soybean oil to the medium as a stabilizer enhanced the expression of the hirudin gene in H. polymorpha with MOX promoter. The production of hirudin in the medium with soybean oil was 320mg/L in a 5L fermenter.     

Production of a polysaccharide, methylan, in Methylobacterium organophilum by controlling ammonium ion

Summary Cell growth increased proportionally to the initial concentration of ammonium ion, however, methylan production was significantly inhibited at the high concentration of ammonium ion. The control of ammonium ion within the desired level(usually 0.45 g/l) was needed to reduce the inhibition. Methylan production was increased to 12.5 g/l by maintaining ammonium ion below 0.15 g/l.     

Optimal conditions for levan formation by an overexpressed recombinant levansucrase

Summary A genetically modified levansucrase, which contained His-affinity tag in its C-terminal, was constructed by PCR reaction using two synthetic primers. This modified protein was produced up to 30 % in total cell protein of E. coli, and was purified by a one-step affinity chromatography. The optimum pH for levan production was pH 5 and the optimum temperature was 0 °C. The higher velocity of levan formation within shorter enzyme reaction times was achieved by increasing the levels of enzyme concentration. The optimal sucrose concentration for levan production was around 20 %. Under these conditions, more than 50 g levan/l was produced.     

Isolation of a root-specific cDNA encoding a ns-LTP-like protein from the roots of bean (Phaseolus vulgaris L.) seedlings

A root-specific cDNA clone, PVR3, was isolated from a bean (Phaseolus vulgaris L.) root cDNA library by a differential screening procedure. The nucleotide sequence of PVR3 contains an open reading frame coding for an 11.14 kDa polypeptide of 102 amino acid residues; the first 25 amino acids correspond to the sequence characteristic of a signal peptide. Comparison of the deduced PVR3 polypeptide sequence with the polypeptide sequences of previously cloned genes indicates that PVR3 may encode a ns-LTP-like protein. Molecular modelling of the PVR3 protein predicts that it has a three-dimensional structure that is similar to the three-dimensional model determined from the maize ns-LTP. The PVR3 mRNA accumulated mainly in the roots of young seedlings. It can be detected at low levels in flowers, but it is not detected in other organs. Genomic Southern blot analysis indicates that the genomic DNA corresponding to PVR3 cDNA is encoded by a single gene or small gene family in the bean genome.     

Intra- and interspecific predation on four life stage groups by the adult females of Metaseiulus occidentalis, Typhlodromus pyri, Neoseiulus fallacis and Amblyseius andersoni

Do adult females of oligophagous species such as Neoseiulus fallacis (Garman) and Metaseiulus occidentalis (Nesbitt) show less intra- and interspecific predation on phytoseiids when other foods are scarce than polyphagous species such as Amblyseius andersoni Chant and Typhlodromus pyri Scheuten? We caged single adult females of each species without food with ten of their own eggs or larvae, with ten eggs or larvae of the other species or with ten nymphs or adult females of M. occidentalis (T. pyri for M. occidentalis). We assessed the ambulatory activity, survival time, egg levels and prey loss in each test. Polyphages (in particular T. pyri) lived longer than oligophages (in particular N. fallacis) without food. The small T. pyri detected its own stages and benefited most by feeding on small active stages of other species. Amblyseius andersoni, the largest mite, fed and gained the most of any species when held with nymphs and female adults. Metaseiulus occidentalis fed on eggs of all four species to enhance survival. The large hyperactive N. fallacis gained the least from these behaviours. Each mite seemed uniquely adapted to survive conditions of scarce prey and these behaviours may explain their roles in phytoseiid mite complexes. Overall, oligophagous adult females fed less and gained less by feeding on phytoseiids than did polyphagous adult females.     

Explanatory pluralism in evolutionary biology

The ontological dependence of one domain on another is compatible with the explanatory autonomy of the less basic domain. That autonomy results from the fact that the relationship between two domains can be very complex. In this paper I distinguish two different types of complexity, two ways the relationship between domains can fail to be transparent, both of which are relevant to evolutionary biology. Sometimes high level explanations preserve a certain type of causal or counterfactual information which would be lost at the lower level; I argue that this is central to the proper understanding of the adaptationist program. Sometimes high level kinds are multiply realised by lower level kinds: I argue that this is central to the understanding of macroevolution.     

The extended replicator

This paper evaluates and criticises the developmental systems conception of evolution and develops instead an extension of the gene's eye conception of evolution. We argue (i) Dawkin's attempt to segregate developmental and evolutionary issues about genes is unsatisfactory. On plausible views of development it is arbitrary to single out genes as the units of selection. (ii) The genotype does not carry information about the phenotype in any way that distinguishes the role of the genes in development from that other factors. (iii) There is no simple and general causal criterion which distinguishes the role of genes in development and evolution. (iv) There is, however, an important sense in which genes but not every other developmental factor represent the phenotype. (v) The idea that genes represent features of the phenotype forces us to recognise that genes are not the only, or almost the only, replicators. Many mechanisms of replication are involved in both development and evolution. (vi) A conception of evolutionary history which recognises both genetic and non-genetic replicators, lineages of replicators and interactors has advantages over both the radical rejection of the replicator/interactor distinction and the conservative restriction of replication to genetic replication.     

Cell-Cell Recognition during Fertilization in a Red Alga, Antithamnion sparsum (Ceramiaceae, Rhodophyta)

A gamete recognition mechanism in Antithamnion sparsum Tokidais proposed based on experiments using various lectins and carbohydrates.Spermatial binding to trichogynes is inhibited by pre-incubationof spermatia with concanavalin A (ConA) and/or L-fucose, whiletrichogyne receptors are blocked by the complementary carbohydrate-methyl D-mannose and/or the lectin Ulex europaeus agglutinin(UeA1). Binding inhibition (40–50%) was observed with10–50 mM carbohydrates and 25–50 µg ml^-1 lectins.The inhibitory effects of ConA and UeA1 is partially reversed(to 80–90% of controls) by addition of -methyl D-mannoseand L-fucose, respectively. Lectin binding to spermatial surfaceswas visualized by Fluorescein isothiocyanate (FITC) conjugatedConA, whereas carbohydrate receptors along the trichogyne andspermatium were localized with -mannosylated-FITC-albumin andL-fucosylated-FITC-albumin, respectively. These results suggestthat gamete recognition in Antithamnion sparsum is mediatedby a double-docking recognition system consisting of spermatiapossessing surface L-fucose receptors and -methyl D-mannosemoiety, and trichogynes possessing the complementary receptors. (Received December 5, 1995; Accepted April 22, 1996)