CHANGES IN THE BASE COMPOSITION OF NUCLEAR RIBONUCLEIC ACID OF NEURONS DURING A SHORT PERIOD OF ENHANCED PROTEIN PRODUCTION

Nuclei from isolated nerve cells were sampled by microdissection. The content and composition of the nuclear RNA was studied and compared with that of the cytoplasmic RNA of Deiters' nerve cells of rabbits. Analyses were made of control nerve cells and of cells in which an enhanced RNA and protein production had been induced by chemical means, tricyano-amino-propene, for 60 minutes. The nuclear RNA content of the control nerve cells was 56 µµg, i.e. 3 per cent of the total RNA content of the nerve cell. The base ratios were: adenine 21.3, guanine 26.6, cytosine 30.8, uracil 21.3. Purine-pyrimidine analyses showed that the nuclear RNA differed significantly from the cytoplasmic RNA in having higher adenine and uracil values. The guanine and cytosine values were high, however, and the ratio G/C was 0.86 as compared with 1.16 for the cytoplasmic RNA. The composition of the nuclear RNA was interpreted as reflecting the extraordinarily strong development of the nucleolus in these neurons. During the 60 minutes of enhanced neuronal RNA production (+25 per cent) the guanine value increased and the uracil value decreased significantly in the nuclear RNA. In the cytoplasmic RNA the guanine value also increased although not so much as the nuclear guanine. The cytoplasmic cytosine value decreased. The result indicated that the production of the characteristic cytoplasmic RNA had been influenced by the change in the nuclear RNA     

Chemical compositions and physical states of chloroplast lipids related to atrazine resistance in Conyza canadensis L.

A comparison of the chemical composition and physical states of chloroplast lipids, of atrazine-resistant (R) and sensitive (S) biotypes of Conyza canadensis L. (horseweed), in the rosetta stage showed: (1) the R biotype contains lower amounts of polar lipids in its thylakoids, as expressed on a chlorophyll basis, than the S biotype. (2) The chloroplasts of the R biotype have higher contents of monogalactosyl diacylglycerol (MGDG) and lower contents of digalactosyl diacylglycerol (DGDG) and phosphatidylglycerol (PG), than those of the S biotype. (3) The chloroplast total lipids exhibit a higher degree of unsaturation in the R biotype. This is due to a higher level of linolenic acid, and a lower level of palmitic acid in the glycolipids. The fatty acid compositions of the phospholipids, except that of PG, do not differ significantly. (4) The lipid matrix of the thylakoid membranes of the R biotype is more fluid than that of the S biotype, as measured by the fluorescence polarization technique. The results are discussed in terms of whether these differences are responsible for the herbicide resistance.     

Dual methylation pathways in lignin biosynthesis

Caffeoyl-coenzyme A (CoA) O-methyltransferase (CCoAOMT) has been proposed to be involved in an alternative methylation pathway of lignin biosynthesis. However, no direct evidence has been available to confirm that CCoAOMT is essential for lignin biosynthesis. To understand further the methylation steps in lignin biosynthesis, we used an antisense approach to alter O-methyltransferase (OMT) gene expression and investigated the consequences of this alteration. We generated transgenic tobacco plants with a substantial reduction in CCoAOMT as well as plants with a simultaneous reduction in both CCoAOMT and caffeic acid O-methyltransferase (CAOMT). Lignin analysis showed that the reduction in CCoAOMT alone resulted in a dramatic decrease in lignin content. The reduction in CCoAOMT also led to a dramatic alteration in lignin composition. Both guaiacyl lignin and syringyl lignin were reduced in the transgenic plants. However, guaiacyl lignin was preferentially reduced, which resulted in an increase in the S/G (syringl/guaiacyl) ratio. We have also analyzed lignin content and composition in transgenic plants having a simultaneous reduction in both CCoAOMT and CAOMT. The reduction in both OMTs resulted in a further decrease in total lignin content. This is in sharp contrast to the effect that resulted from the reduction in CAOMT alone, which only decreased the syringl lignin unit without a reduction in overall lignin content. These results unequivocally demonstrate that methylation reactions in lignin biosynthesis are catalyzed by both CCoAOMT and CAOMT.     

ENOD12, an early nodulin gene, is not required for nodule formation and efficient nitrogen fixation in alfalfa.

To demonstrate the importance of an extensively studied early nodulin gene ENOD12 in symbiotic nodule development, plants of different Medicago sativa subspecies were tested for the presence or absence of ENOD12 alleles. In M. s. ssp coerulea w2 (Mcw2), two ENOD12 genes were detected, whereas in M. s. ssp quasifalcata k93 (Mqk93) only one gene was present. In both plants, the ENOD12 genes were expressed in nodules induced by Rhizobium meliloti. The nucleotide sequence of the ENOD12 genes showed that the two Mcw2-specific genes were similar to the ENOD12A and ENOD12B genes of the tetraploid M. s. ssp sativa. ENOD12 from Mqk93 was similar to the corresponding gene found in M. truncatula. From the aligned ENOD12 sequences, an evolutionary tree was constructed. Genetic analysis of the progenies of a cross between Mqk93 and Mcw2 showed that several offspring in F1 carried a null allele originating from Mcw2, and among the F2 progenies, plants with the null allele only lacking the ENOD12 gene appeared. Surprisingly, the ENOD12-deficient plants were similar to their wild-type parents in viability, nodule development, nodule structure, and nitrogen fixation efficiency. Therefore, we concluded that in Medicago the ENOD12 gene is not required for symbiotic nitrogen fixation. Furthermore, we proposed that the heterozygous nature of these legumes can be exploited for the identification of mutated alleles of other known nodulin genes; this will permit the construction of plant mutants deficient in these genes.     

Cell volume dependence of 1H spin-echo NMR signals in human erythrocyte suspensions. The influence of in situ field gradients

The 1H spin-echo NMR signal amplitudes and intensities of low molecular weight solutes in the cytoplasm and extracellular fluid of suspensions of human erythrocytes were shown to depend on the osmotic pressure of the media. At low osmotic pressure (220 mosM/kg) freeze-thaw lysis of the cells resulted in signal enhancement which was greatest for extracellular molecules, but both intra- and extracellular species were almost equally enhanced at 580 mosM/kg. This effect is due to field gradients formed at cell boundaries as a result of differences in magnetic susceptibility between the medium and the cytoplasm. T2 values measured using the Carr-Purcell-Meiboom-Gill pulse sequence, with tau = 0.0003 s, depended little on cell volume and absolute changes in volume magnetic susceptibility were also small. The mean field gradients, calculated from data obtained on cell suspensions at different osmotic pressures, were in the range 0.25-1.98 G/cm and 0.89-2.09 G/cm for intra- and extracellular compartments, respectively. The maintenance of isotonicity of the extracellular fluid during metabolic studies of cell suspensions is important in order to avoid artefacts in the determination of metabolite concentrations when using the spin-echo technique. Conversely it may be possible to perform transport measurements using spin-echo NMR to monitor the cell volume changes which occur during the transmembrane migration of molecules.     

Genome sequencing and analysis of Mangalica,a fatty local pig of Hungary

Background

Mangalicas are fatty type local/rare pig breeds with an increasing presence in the niche pork market in Hungary and in other countries. To explore their genetic resources, we have analysed data from next-generation sequencing of an individual male from each of three Mangalica breeds along with a local male Duroc pig. Structural variations, such as SNPs, INDELs and CNVs, were identified and particular genes with SNP variations were analysed with special emphasis on functions related to fat metabolism in pigs.

Results

More than 60 Gb of sequence data were generated for each of the sequenced individuals, resulting in 11× to 19× autosomal median coverage. After stringent filtering, around six million SNPs, of which approximately 10% are novel compared to the dbSNP138 database, were identified in each animal. Several hundred thousands of INDELs and about 1,000 CNV gains were also identified. The functional annotation of genes with exonic, non-synonymous SNPs, which are common in all three Mangalicas but are absent in either the reference genome or the sequenced Duroc of this study, highlighted 52 genes in lipid metabolism processes. Further analysis revealed that 41 of these genes are associated with lipid metabolic or regulatory pathways, 49 are in fat-metabolism and fatness-phenotype QTLs and, with the exception of ACACA, ANKRD23, GM2A, KIT, MOGAT2, MTTP, FASN, SGMS1, SLC27A6 and RETSAT, have not previously been associated with fat-related phenotypes.

Conclusions

Genome analysis of Mangalica breeds revealed that local/rare breeds could be a rich source of sequence variations not present in cosmopolitan/industrial breeds. The identified Mangalica variations may, therefore, be a very useful resource for future studies of agronomically important traits in pigs.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2164-15-761) contains supplementary material, which is available to authorized users.     

Monitoring the Effect of Docetaxel Treatment in MCF7 Xenografts Using Multimodal In Vivo and Ex Vivo Magnetic Resonance Methods,Histopathology, and Gene Expression

The purpose of this study was to evaluate the sensitivity of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI), diffusion-weighted (DW)-MRI, in vivo MR spectroscopy (MRS), and ex vivo high-resolution magic angle spinning (HR MAS) MRS for the detection of early treatment effects after docetaxel administration. Docetaxel is an antitumor agent that leads to mitotic arrest, apoptosis, and mitotic catastrophe cell death. Gene expression analysis was performed to detect altered regulation in gene expression pathways related to docetaxel treatment effects. Histopathology was used as a measure of alterations in apoptosis and proliferation due to docetaxel. Experiments were performed using MCF7 mouse xenografts, randomized into a docetaxel (30 mg/kg) treatment group and a control group given saline. MRI/MRS was performed 1 day before treatment and 1, 3, and 6 days after treatment. Parametric images of the extracellular extravascular volume fraction (v_e) transfer constant (K^trans) and the apparent diffusion coefficient (ADC) were calculated from the DCE-MRI and DW-MRI data. Biopsies were analyzed by HR MAS MRS, and histopathology and gene expression profiles were determined (Illumina). A significant increase in the ADC 3 and 6 days after treatment and a significant decrease in total choline and a higher v_e were found in treated tumors 6 days after treatment. No significant difference was found in the K^trans between the two groups. Our results show that docetaxel induces apoptosis and decreases proliferation in MCF7 xenografts. Further, these phenomena can be monitored by in vivo MRS, DW-MRI, and gene expression.     

Germ line specific expression of a protein phosphatase Y interacting protein (PPYR1) in Drosophila

PPYR1, the product of the CG15031 gene, was identified as a protein phosphatase Y (PPY) interacting protein in Drosophila melanogaster using a yeast two-hybrid screen. PPYR1 displays a biphasic expression pattern: the maternal protein is abundant in the developing egg chambers and in the early embryos, while the zygotic protein appears later in development and is localized specifically in the testes of the males. The maternal and zygotic gene products differ from each other in their size having apparent molecular masses of 47 and 66 kDa, respectively. The maternal PPYR1 is localized in the cytoplasm of the follicular and nurse cells and is deposited as a ribonucleoprotein complex in the oocyte. In the early embryos, the PPYR1 is distributed evenly, and it gradually diminishes during embryonic development. Zygotic PPYR1 is expressed exclusively in the testes, predominantly in the cytoplasm of the spermatocytes. PPY is localized in the nuclei of the same cells. Our results suggest that PPYR1 has two distinct developmental isoforms: a maternal protein the expression of which is independent of PPY and a zygotic protein which is co-expressed with PPY.