Metabolic characterization of high- and low-yielding strains of Penicillium chrysogenum

A recently developed method for analyzing metabolic networks using ¹³C-labels was employed for investigating the metabolism of a high- and a low-yielding strain of Penicillium chrysogenum. Under penicillin-producing conditions, the flux through the pentose phosphate (PP) pathway in the high- and the low-yielding strains was estimated to 70 and 66, respectively. When the high-yielding strain was cultivated in a medium without the penicillin side chain precursor, phenoxyacetic acid, the PP pathway flux was estimated as 71. Thus, in all three experiments, the flux through the PP pathway was almost constant with an average value of 69 ± 3, and the method therefore allows for a very reproducible estimation of the PP pathway flux. Phenoxyacetic acid was found to be a source of cytosolic acetyl-CoA and thereby a source of precursors for the biosynthesis of 2-aminoadipic acid, which is a central amino acid in penicillin biosynthesis. However, the labeling patterns also indicated the presence of an unrecognized pathway to cytosolic acetyl-CoA. Received: 20 December 1999 / Received revision: 7 March 2000 / Accepted: 10 March 2000     

Influence of Extreme Environmental Factors on the Dynamics of Abundance of the Pink Salmon <Emphasis Type="Italic">Oncorhynchus gorbuscha</Emphasis>

The correlation between the number of returned fish and the spawners of the parent generation recorded in the rivers (the reproduction index) has been analyzed in a series of generations of the five largest stocks of pink salmon Oncorhynchus gorbuscha in the Sakhalin-Kuril region. The hypothesis that the appearance of low-yielding generations of pink salmon was mainly due to the impact of typhoons as extreme environmental factors has been confirmed. Low values of the reproduction index of pink salmon generations that have been exposed to typhoons during embryonic development in the rivers (redds) or during the feeding period of juveniles in the coastal region of the sea (the next few days after downstream migration) allow for a conclusion on their significant importance for the formation of the abundance of this species. During some adjacent year groups, the frequency of typhoons attributable to the indicated periods of the pink salmon’s life cycle increases, this causes a number of low-yielding generations. At the same time, the strength of the typhoons and the limits of their impact are constantly changing, which explains the lack of synchronism in the sharp changes in the pink salmon population of all the stocks in the region.     

Construction of introgression lines carrying wild rice (Oryza rufipogon Griff.) segments in cultivated rice (Oryza sativa L.) background and characterization of introgressed segments associated with yield-related traits

Introgression lines (ILs) are useful tools for precise mapping of quantitative trait loci (QTLs) and the evaluation of gene action or interaction in theoretical studies. A set of 159 ILs carrying variant introgressed segments from Chinese common wild rice (Oryza rufipogon Griff.), collected from Dongxiang county, Jiangxi Province, in the background of Indica cultivar (Oryza sativa L.), Guichao 2, was developed using 126 polymorphic simple sequence repeats (SSR) loci. The 159 ILs represented 67.5% of the genome of O. rufipogon. All the ILs have the proportions of the recurrent parent ranging from 92.4 to 99.9%, with an average of 97.4%. The average proportion of the donor genome for the BC₄F₄ population was about 2.2%. The mean numbers of homozygous and heterozygous donor segments were 2 (ranging 0–8) and 1 (ranging 0–7), respectively, and the majority of these segments had sizes less than 10 cM. QTL analysis was conducted based on evaluation of yield-related traits of the 159 ILs at two sites, in Beijing and Hainan. For 6 out of 17 QTLs identified at two sites corresponding to three traits (panicles per plant, grains per panicle and filled grains per plant, respectively), the QTLs derived from O. rufipogon were usually associated with an improvement of the target trait, although the overall phenotypic characters of O. rufipogon were inferior to that of the recurrent parent. Of the 17 QTLs, 5 specific QTLs strongly associated with more than one trait were observed. Further analysis of the high-yielding and low-yielding ILs revealed that the high-yielding ILs contained relatively less introgressed segments than the low-yielding ILs, and that the yield increase or decrease was mainly due to the number of grain. On the other hand, low-yielding ILs contained more negative QTLs or disharmonious interactions between QTLs which masked trait-enchancing QTLs. These ILs will be useful in identifying the traits of yield, tolerance to low temperature and drought stress, and detecting favorable genes of common wild rice.     

Alterations in the relative abundance of Haptoglobin (Hp) transcripts in total milk somatic cells during different stages of lactation cycle in high yielding cross-bred cows

The expression profile of Haptoglobin (Hp) gene in total milk somatic cells (SCC) of high-yielding cross-bred Karan Fries (KF) was studied during early, mid, and late lactation cycle. Milk samples (200 ml/animals) were collected from 10 high-yielding and 10 low-yielding cows throughout the lactation cycle (from day 7 to day 300) with an interval of one month. Relative mRNA expression profiles of Hp by RT polymerase chain reaction was studied in high-yielding cows, whereas low-yielding cows were taken as control. The folds of induction of Hp was significantly (p < 0.001) downregulated by a mean factor of 0.207 in milk SCC during early lactating cows. Whereas, it was significantly (p < 0.01) upregulated by a mean factor of 20.888 during mid lactation. The expression was unaltered during the late lactation. The study demonstrates that Hp is synthesized within the mammary gland and significantly upregulated during mid-lactation period compared to other stages of lactation cycle.     

Histidine sensitive variant of the blue-green alga Nostoc muscorum: response to corepressors of histidine biosynthesis.

Summary A model has been proposed to account for growth inhibition by L-histidine in a variant strain of Nostoc muscorum. This strain has been characterized for its response to 3-amino-1,2,4-triazole and 1,2,4-triazole-3-alanine known to act as false corepressors of the histidine biosynthesis genes. The histidine sensitive strain retained its sensitivity to triazole alanine while the inhibitory effects of aminotriazole were much reduced indicating a change in regulation of his genes. The probable interactions between nif and his genes in cyanobacteria (blue-green algae) have been discussed.     

Chemical investigation of wheat

Summary The extent and the mechanism of phytic acid decomposition in germinating wheat grain of a low-yielding and a high-yielding wheat variety have been investigated.While in the high-yielding variety this decomposition was most important on the first, fifth, and seventh day of germination, in the low-yielding variety extensive decomposition began only on the second day and reached its maximum value on the fifth day of germination. If one accepts the criterion of Mellanby for the rate of phytic acid decomposition, it appears that phytic acid is completely decomposed within seven days in the high-yielding variety and within six days in the low-yielding variety. The increase of free orthophosphate was not equivalent to the decrease of phytic acid, the difference representing the amount of orthophosphate phosphorus uptake in oxidative and photosynthetic phosphorylation.It was found that enzymatic hydrolysis of phytic acid in germinating wheat grain occurred stepwise, by the successive liberation of phosphoric acid and through the intermediate formation of penta-, tetra-, tri-, di-, and monophosphates of inositol, the final products being inositol and phosphoric acid. In ripe wheat grain before germination, only inositol hexaphosphate (phytic acid) was present.Paper 7: Glasnik hem. drustva (Beograd (Bull. soc. chim. Beograd)),28, 303–325 (1963)     

The perfect and imperfect states ofSporobolomyces salmonicolor

A strain ofSporobolomyces salmonicolor from which both the haplophase and diplophase had been recovered was found to form teliospores which germinated usually by the formation of a non-septate promycelium bearing 2–4 sporidia. The strain has consequently been transferred to the new basidiomycetous yeast genusAessosporon, for which a diagnosis and type are given, and which has been assigned to the Tilletiaceae.     

Isolation and study of a strain of Candida tropicalis growing on n-alkanes

Summary A strain of Candida tropicalis has been isolated from soil using a mineral medium that contained n-tetradecane as sole source of carbon. This strain has been studied and variants have been isolated. In contrast to the original strain in which hydrocarbon degradation is linked to enzymatic induction mechanisms, the variant 101 behaves like a constitutive strain for n-tetradecane.     

Stable transformation and long-term maintenance of transgenic <Emphasis Type="Italic">Taxus</Emphasis> cell suspension cultures

A cell line of Taxus cuspidata has been transformed with wild-type Agrobacterium rhizogenes ATCC strain 15834 containing binary vector pCAMBIA1301 and, separately, with A. tumefaciens strain EHA105 containing binary vector pCAMBIA1305.2. Additionally, a cell line of T. chinensis has been transformed with wild-type A. rhizogenes ATCC strain 25818 containing binary vector pCAMBIA1301. The two transgenic T. cuspidata cell lines have been maintained in culture for more than 20 months, and the transgenic T. chinensis cell line for more than 9 months, with no loss of reporter gene expression or antibiotic resistance. The introduced genes had no discernable effect on growth or Taxol production in the transgenic cell lines when compared to the parent control. The methods for transforming non-embryogenic Taxus suspension cultures are described.     

New haplotype and inter‐strain reproductive compatibility of Wolbachia‐uninfected alfalfa weevil,Hypera postica (Coleoptera: Curculionidae), in Japan

Hypera postica is a univoltine invasive pest of alfalfa, Medicago sativa, in North America. In Japan, H. postica was first found in 1982 from Fukuoka and Okinawa Prefectures and became a serious pest of Chinese milk vetch, Astragalus sinicus, cultivated as a honey source for humans and green manure for rice. In North America, three strains, Western, Eastern and Egyptian, have been identified and the Western strain is infected with Wolbachia, which causes complete inter‐strain reproductive incompatibility. In contrast, only Western and Egyptian strains had been reported throughout Japan and none of the Western strain examined for the Fukuoka populations in northern Kyushu was infected with Wolbachia. First, we screened populations from northern Kyushu collected since 1982 for geographical and chronological distribution of the Eastern strain. The Eastern strain has been found at low frequencies since 1985 and is still present in 2014. Second, we experimentally tested our hypothesis that inter‐strain crosses between uninfected Western‐strain males and Egyptian‐strain females should produce viable offspring. We crossbred virgin adults reared individually from field‐collected larvae and confirmed that the F₁ eggs of crosses between the Western‐strain males and the Egyptian‐strain females develop successfully into larvae.     

Construction of a new strain of Streptomyces violaceoniger,having strong,constitutive and stable glucose-isomerase activity

Summary A newly isolated strong Streptomyces promoter (P1) has been cloned in front of the xylA gene of Streptomyces violaceoniger. This led to a strong and constitutive expression. To avoid instability of plasmid and glucose isomerase activity, the P1-xylA gene has been integrated into the chromosome using the integrative vector pTS55. The resultant CBS1 strain has about seven times higher glucose-isomerase activity in absence of xylose compared to that of wild type strain fully induced by xylose. In addition, glucose isomerase specific activity of the CBS1 strain increases in the secondary growth phase, in contrast to wild type strain.     

The area under the function: an index for selecting desirable genotypes

The linear regression approach has been widely used for selecting high-yielding and stable genotypes targeted to several environments. The genotype mean yield and the regression coefficient of a genotype's performance on an index of environmental productivity are the two main stability parameters. Using both can often complicate the breeder's decision when comparing high-yielding, less-stable genotypes with low-yielding, stable genotypes. This study proposes to combine the mean yield and regression coefficient into a unified desirability index (D _i). Thus, D _i is defined as the area under the linear regression function divided by the difference between the two extreme environmental indexes. D _i is equal to the mean of the i ^th genotype across all environments plus its slope multiplied by the mean of the environmental indexes of the two extreme environments (symmetry). Desirable genotypes are those with a large D _i. For symmetric trials the desirability index depends largely on the mean yield of the genotype and for asymmetric trials the slope has an important influence on the desirability index. The use of D _i was illustrated by a 20-environments maize yield trial and a 25-environments wheat yield trial. Three maize genotypes out of nine showed values of D _i 's that were significantly larger than a hypothetical, stable genotype. These were considered desirable, even though two of them had slopes significantly greater than 1.0. The results obtained from ranking wheat genotypes on mean yield differ from a ranking based on D _i .     

Distribution and homology of plasmids in several strains of Cyanothece

The plasmid distribution of several clonal isolates of the unicellular, diazotrophic, cyanobacterium Cyanothece sp. has been analyzed. The Cyanothece isolates contain three to four plasmids ranging in size from 4.8 kb to 40 kb. The plasmid profiles of three Cyanothece strains (BH63, BH68, BH93) indicated that strains BH68 and BH93 were closely related and that strain BH63 may be more distantly related. A small 4.8-kb plasmid (pSE480), from the clonal isolate Cyanothece sp. strain BH68F, has been subcloned and restriction mapped. Ten restriction sites have been mapped, five of which are unique and suitable for further subcloning. Southern hybridization revealed that this plasmid was present in two out of five clonal isolates of strain BH68 and in one isolate of strain BH93. A 10-kb plasmid from strain BH68F (pSE1000) was found in all of the BH68 isolates and was absent in the BH93 isolate, Cyanothece sp. strain BH93A. No notable physiological changes were observed in the absence of either the 4.8-kb or 10-kb plasmids. Therefore, these plasmids remain cryptic. Further analysis of these plasmids may provide insight into the function of these plasmids and will allow the construction of shuttle vectors for gene transfer experiments.     

Genetic control ofHylemya antiqua III. Differences in pupation ability between two strains

Some relevant traits of a wild (L) and a laboratory (C) strain of Hylemya antiqua (Meigen ), determining differences in their pupation ability under experimental conditions have been investigated in relation to genetic control. The wild strain showed an intrinsic higher pupation ability than the laboratory strain. The minimum feeding period was 0.6 days longer for the C strain. The minimum larval dry weight was different for the two strains. With a normal feeding period C larvae pupated on average 1.63 days later than L larvae. By the shortening of the larval feeding period an acceleration of the larval development of both strains was observed: the acceleration of development was more marked for the wild strain. This result has been contrasted with published works on Drosphila. The consequences of these differences as far as the competitive ability of each strain is concerned, have been discussed in relation to genetic control.     

Greening and strictosidine lactam production in two cell lines of Vinca major cv. variegata

Two cell lines of Vinca major L. cv. variegata produced strictosidine lactam as the main alkaloid. Quantities varied from 500–1000 g/g DW in the high-yielding line and 1–100 g/g DW in the low-yielding line. Transfer of cells to alkaloid production medium resulted in a 6–8 fold increase in alkaloid production with the high-yielding line, some increase in the low-yielding line and in both lines induced intense greening (up to 200 g chlorophyll/g DW) indicating chloroplast differentiation. Though in the source plant leaves are the main storage site, no correlation between alkaloid accumulation and chloroplast differentiation could be found.NRCC No. 26184.     

Isolation of Bacillus megaterium Mutants That Produce High Levels of Heterologous Protein,and Their Use to Construct a Highly Mosquitocidal Strain

A xylose-regulated plasmid expression system for producing high levels of recombinant proteins in Bacillus megaterium has recently been described [Appl Microbiol Biotechnol 35:594, 1991]. Using an antibiotic resistance protein as the expressed protein, we have been able to select mutant plasmids that produce increased levels of heterologous protein. The mutant plasmids show increased segregational stability and have lost the ability to be transformed into Escherichia coli. The same selection protocol has been used to isolate a mutant strain producing high levels of the Bacillus sphaericus mosquitocidal binary toxin. This strain shows toxicity to Culex quinquefasciatus larvae that is comparable to B. sphaericus 2362 and higher than a B. megaterium strain with the original expression plasmid. This approach may be generally useful for high-level regulated protein expression in B. megaterium. Received: 6 December 1996 / Accepted: 28 January 1997     

Histidine sensitive strain of the blue-green alga Nostoc muscorum: possible nif-his interactions

Summary A variant strain of the nitrogen-fixing bluegreen alga Nostoc muscorum, displaying impairment in its elemental nitrogen dependent growth and complete inhibition of growth by L-histidine in otherwise nitrogen-free medium, has been isolated and characterized for its response to L-glutamic acid and L-glutamine in presence of other inorganic nitrogen sources. A model based on the possibility of nif-his interaction has been proposed to account for the observed behaviour of the strain. It is inferred that the two sets of genes may occupy neighbouring positions on the blue-green algal genome.     

Degradation and bioconversion of aliphatic and aromatic hydrocarbons by Rhodococcus ruber 219

 A tetrahydrofuran-degrading bacterial strain, which had previously been tentatively assigned as Rhodococcus sp. strain 219, has now been identified as Rhodococcus ruber using physiological and chemotaxonomical tests. A comparison with the type strain DSM 43338 has revealed that the new strain differs in its ability to degrade or convert tetrahydrofuran and compounds of similar structure such as 2,5-dimethyltetrahydrofuran or tetrahydropyran. Tetrahydrofuran acts as an inducer for its degradation. When tetrahydrofuran-induced cells were incubated with 2,5-dimethyltetrahydrofuran two primary metabolites could be detected by gas chromatography, and 2-hydroxyhexane-5-one and hexane-2,5-dione were isolated and characterized by ¹H-NMR spectroscopy or as dinitrophenylhydrazones. The formation of these intermediates is consistent with an initial 2hydroxylation of the cyclic ether, which has not yet been described in microorganisms. Received: 19 July 1995/Received last revision: 31 October 1995/Accepted: 6 November 1995     

IS4 at its chromosomal site in E. coli K12

Summary IS4 DNA has been isolated in pure form. Hybridization of this DNA against restricted DNA of several E.coli K12 strains by Southern's blotting technique has shown that, in most strains, only one copy of IS4 is present. Though the restriction fragments around this site differ in size, IS4 can be shown always to be located at the same site. In one strain, one additional copy has been found in a new location. In this strain, IS4 in its original location has been retained.     

PHYLOGENETIC PLACEMENT,GENOME SIZE,AND GC CONTENT OF THE LIQUID‐HYDROCARBON‐PRODUCING GREEN MICROALGA BOTRYOCOCCUS BRAUNII STRAIN BERKELEY (SHOWA) (CHLOROPHYTA)1

We report the genome size and the GC content, and perform a phylogenetic analysis on Botryococcus braunii Kütz., a green, colony‐forming, hydrocarbon‐rich alga that is an attractive source for biopetroleum. While the chemistry of the hydrocarbons produced by the B race of B. braunii has been studied for many years, there is a deficiency of information concerning the molecular biology of this alga. In addition, there has been some discrepancy as to the phylogenetic placement of the Berkeley (or Showa) strain of the B race. To clarify its classification, we isolated the Berkeley strain nuclear SSU (18S) rRNA gene and β‐actin cDNA and used these sequences for phylogenetic analysis to determine that the Berkeley strain belongs to the Trebouxiophyceae class. This finding is in agreement with other B races of B. braunii, indicating the Berkeley strain is a true B race of B. braunii. To better understand molecular aspects of B. braunii, we obtained the Berkeley strain genome size as a first step in genome sequencing. Using flow cytometry, we determined the B. braunii Berkeley genome size to be 166.2 ± 2.2 Mb. We also estimated the GC content of the Berkeley strain as 54.4 ± 1.2% for expressed gene sequences.