A survey of the non-esterified fatty acids and binding proteins in the plasmas of selected animals

• 1.1. The levels of non-esterified fatty acids (NEFA) in the plasma of a variety of animals have been estimated.
• 2.2. Only one of seven elasmobranchs contained detectable levels of NEFA.
• 3.3. The two crustaceans examined contained very low levels.
• 4.4. All the other animals contained circulating levels of a variety of NEFA ranging from 14 to 24 carbon atoms.
• 5.5. The elasmobranchs are unique in that they also do not possess proteins in the serum which bind fatty acids.

     

Respiratory function and nucleotide composition of erythrocytes from tropical elasmobranchs

• 1.1. Oxygen carrying capacity and parameters of erythrocyte-oxygen binding are similar for a range of elasmobranchs with markedly different swimming behaviour.
• 2.2. Erythrocyte nucleotide components in sharks include the allosteric hemoglobin modifiers GTP and ATP in similar ratios, and the total pool appears independent of locomotory activity. A rhinobatoid ray had no detectable erythrocyte trinucleotides, but had an appreciable pool of AMP together with IMP.
• 3.3. There was no evidence for either urea or NaCl modulation of hemoglobin function in erythrocytes from a carcharhinid shark.
• 4.4. These observations lead to the conclusion that parameters of the oxygen transport system in elasmobranchs are highly conserved.

     

Specificity of transcription of single-copy DNA in different rat tissues

• 1.1. The amount of single-copy DNA sequences transcribed in normal tissues of adult rats (brain and liver) and in the Guerin ascites tumor (GAT) was determined by hybridization of in vitro labelled ¹²⁵I-single-copy rat DNA with a vast excess of total nuclear RNA to very high Rot values (up to 350,000).
• 2.2. The tissue specificity of total nuclear RNA (nRNA) was estimated by annealing of single-copy DNA to a mixture of nuclear RNAs of two different organs (brain + GAT; liver + GAT).
• 3.3. Liver and GAT RNAs annealed to about 12% of the single-copy DNA.
• 4.4. Hybridization with a mixture of the two RNAs increased slightly the amount of hybridization.
• 5.5. In contrast to other tissues, brain nuclear RNA hybridized to a much higher level (20% of the single copy DNA). Addition of GAT RNA did not increase this value.

     

A comparative study of nuclear and chloroplast DNA dependent RNA polymerases from wheat leaves

• 1.1. Three DNA dependent RNA polymerases have been purified from chromatin and chloroplast fractions of wheat leaves.
• 2.2. The purified enzymes were completely dependent on exogenous DNA after purification by glycerol gradient, DEAE-Sephadex and phosphocellulose chromatography.
• 3.3. The nuclear enzymes, I and II, showed a strong preference for denatured nuclear DNA, whereas the chloroplast enzyme preferred denatured chloroplast DNA.
• 4.4. The three enzymes require either Mg²⁺ or Mn²⁺ for activity.
• 5.5. α-amanitin specifically inhibited RNA polymerase II but has no effect on polymerase I and chloroplast polymerase.
• 6.6. Enzyme I is most active at very low ionic strength (0.10 mM KC1), whereas enzyme II and chloroplast enzyme show maximum activity at 150mM and 50 mM KC1 respectively.

     

Serum lipoproteins of sea bass (Dicentrarchus Labrax L.). Purification and partial characterization by density gradient ultracentrifugation and agarose column chromatography

• 1.1. Five classes of sea bass serum lipoproteins were purified by single vertical spin ultracentrifugation and agarose column chromatography
• 2.2. VLDL, beta migrating, are the larger and less dense lipoproteins.
• 3.3. LDL are the more heterogeneous in size, ranging from 11 × 10⁶ to 1 × 10⁶.
• 4.4. HDL represent the predominant class which, on the basis of density and electrophoresis migration, is differentiated in three subclasses.
• 5.5. VHDL float at a density > 1.22 mg/ml, which corresponds to the density of the other serum lipoproteins. This subclass, with an apparent molecular weight of 1.5 × 10⁵, resembles the albumin-like fatty acids binding proteins, shown in mammals and teleosts and absent in elasmobranchs.

     

Isolation of dna and rna from Streptococcus sobrinus OMZ176 using CsTFA gradients

• 1.1. A simple procedure for isolation of high molecular weight genomic DNA, and RNA, from Streptococcus sobrinus OMZ176 is described.
• 2.2. Cell cultures were grown aerobically for 10 hr.
• 3.3. Spheroplast formation and lysis was achieved by mutanolysin/lysozyme-dependent digestion of the cell wall, followed by N-lauroylsarcosinate-mediated lysis.
• 4.4. Nucleic acids were isolated directly from cell-lysates using cesium-trifluoroacetate (CsTFA) densitygradient centrifugation.
• 5.5. Three different centrifugation regimes were tested: self-generated density gradients in a fixed angle rotor; self-generated density-gradients in a swinging-bucket rotor; pre-formed density-gradients in a swinging-bucket rotor.
• 6.6. Genomic DNA isolated by the CsTFA-procedure was found to have higher purity as compared to genomic DNA isolated in a conventional CsCl gradient.
• 7.7. Isolated DNA was shown to be of a quality suitable for applications in molecular biology.

     

Nucleic acids accumulation of silk gland of Bombyx mori in relation to silk protein

• 1.1. Productivity of silk, properly fibroin, of the silkworm Bombyx mori was in proportion to the amount of RNA accumulation in the posterior division of silk gland.
• 2.2. DNA content of the silk gland of a line of high silk productivity was twice as much as that of low productivity. A DNA molecule can transcribe RNA, ranged from 3 × 10⁶ to 6 × 10⁶ molecules.
• 3.3. An application of actinomycin to larvae lowered an accumulation of RNA in the silk gland and resulted in a decrease of silk production.
• 4.4. Even under the upper limit of starvation by which the larvae complete their life, the silk gland kept a normal level of the DNA content, except that it lost the synthesizing activity of RNA.
• 5.5. Treatment of larvae with juvenile hormone occasionally induced another DNA replication of the silk gland.

     

Dna breakage and inactivation resulting from hydroxylamine and/or cis-Diamminedichloroplatinum(Ii) interactions with plasmid dna

• 1.1. Occurrence of lesions induced in plasmid DNA by cis-DDP and by HA was quantified both as a transforming activity and as conformation integrity of supercoilcd pBR322 DNA. Fifty per cent decrease of the biological activity of plasmid DNA, not accompanied by measurable change of DNA conformation, was observed after a single exposure of DNA to cis-DDP (1 hr/37°C).
• 2.2. HA induced conversion of supercoiled DNA to other topological forms in a dose-dependent manner.
• 3.3. One- and two-strand DNA breaks were determined electrophoretically with high sensitivity. Cis-DDP exposed DNA relaxed at 30 times lower HA concentration compared to intact DNA.
• 4.4. This effect may be connected with a local distortion of DNA structure at the cis-DDP—DNA bond, which makes possible high effectivity of HA-DNA interaction.
• 5.5. On other hand, biological activity stayed at the 50% level despite breaks induced in DNA.
• 6.6. This finding supports the idea that DNA breaks occur at the locations which were modified during the exposure of DNA to cis-DDP.
• 7.7. The importance of the DNA structure during interaction with HA may be seen during HA-DNA interaction at heat-denaturation of supercoiled DNA. At this condition, the DNA breaks were induced at 100 times lower concentration of HA.
• 8.8. We conclude, on the basis of these results and results published earlier, that local distortion of supercoiled DNA structure, which is caused by the cu-DDP bond, and the local DNA uncoiling caused by heat-denaturation are related to high HA-DNA reactivity.

     

Purification and characterization of a manganese containing superoxide dismutase from bovine heart mitochondria

• 1.1. A manganese containing superoxide dismutase from bovine heart mitochondria was isolated and characterized.
• 2.2. It has a molecular weight of about 86,000 and is composed of 4 noncovalently bound subunits of equal size.
• 3.It appears to contain 2 mole manganese per mole enzyme.
• 4.The carbohydrate content is very low.
• 5.The specific activity and amino acid composition are similar to those of other mitoehondrial superoxide dismutases.
• 6.The enzyme forms complexes with ampholytes and can therefore not be analysed by isoelectric focusing.

     

Alkylating spin labels for spin-labelling of DNA

• 1.1. Five alkylating spin labels, termed SL1, SL2, SL3, SL4 and SL5, have been synthesized and their suitability for spin-labelling of DNA was studied.
• 2.2. It was found that one of them (SL5) lost its free radical moiety under the conditions of spin-labelling, thus giving DNA with no EPR signal.
• 3.3. Two of the spin labels (SL2 and SL4) denatured DNA and therefore they were not appropriate for spin-labelling of double stranded DNA.
• 4.4. The spin labels SL1 and SL3 as well as the recently synthesi/ed HMSL [Raikova et al. (1982) Int. J. Biochem. 14, 41–46.] showed a low destabilizing effect on the DNA double helix and gave spin-labelled DNA with very immobilized EPR spectra (2Azz = 40G).
• 5.5. These three spin labels could be recommended as suitable for application in the EPR spectrometry of DNA.

     

Localization of α-tocopherol in hepatic chromatin from rats maintained on a tocopherol-deficient diet

• 1.1. A very significant amount of α-tocopherol was localized in hepatic chromatin when [³H]d-α-tocopherol was intravenously injected into rats maintained on tocopherol-deficient diet.
• 2.2. The site of association of α-tocopherol in the intrachromatin domain was examined by several methods.
• 3.3. The results show that α-tocopherol is predominantly localized in the heterochromatin and is associated with proteins exhibiting the characteristics of nonhistone proteins that have very high affinity for DNA.

     

The restriction analysis of nDNA from the corvids (Passeriformes,aves)

• 1.1. The nDNA of carrion crow Corvus corone L., hooded crow C. cornix L., their hybrids, as well as magpie Pica pica L., were digested by the tetranucleotide recognizing restriction enzymes Sau3a, AluI, BspRI and then analysed using electrophoresis with microdensitometry.
• 2.2. The distribution patterns of restriction DNA fragments proved to be nuclease- and taxon specific.
• 3.3. The observed families of repeated sequences are characterized by different length (from 30 bp to 23 tbp), number of copies in genome (approximately 10³ and 10⁶) and supposedly different types of organization and evolutionary age.
• 4.4. The total DNA amount identified in the form of discrete fragments is 16 and 19–21% for magpie and crows, respectively.
• 5.5. The DNA restriction patterns of hybrid forms do not differ from the parental species.

     

Monoclonal antibodies to antigen binding protein of annelids (Lumbricus terrestris)

• 1.1. Monoclonal antibodies (mAb) to antigen binding protein (ABP) of the earthworm Lumbricus terrestris have been prepared.
• 2.2. The specificity of mAb for a determinant located outside the antigen binding site was determined and verified in inhibition experiments.
• 3.3. The mAb were used for isolation of a 56 kDa ABP by an immunoprecipitation technique.
• 4.4. The binding of mAb to coelomocytes has demonstrated the existence of two cell populations, one with low and the other with high densities of ABP molecules on the cell membranes.

     

Distribution of free l-histidine and related dipeptides in the muscle of fresh-water fishes

• 1.1. From the muscle of 20 species of fresh-water fishes, l-histidine, carnosine, anserine, and balenine were analysed by high-performance liquid chromatography.
• 2.2. All cyprinoidei fishes contained significant amount of l-histidine and trace of dipeptides.
• 3.3. High concentration of anserine was found in salmonoidei fishes, irrespective of salmonidae and osmeridae.
• 4.4. Two species of anguilloidei contained large amount of carnosine, small of l-histidine, and determinable of anserine and balenine.
• 5.5. Only trace amounts of these compounds were found in percoidei fishes.
• 6.6. The levels of these compounds represented no large difference among species belonging to sub-order group as well as family.

     

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Urea excretion rates and waste nitrogen concentrations during metamorphosis of Xenopus laevis Daudin

• 1.1. Serum urea, ammonia concentrations in the blood and excretion were measured in tadpoles of different stages and juveniles of Xenopus laevis.
• 2.2. The urea excretion rate was determined with the help of injected ¹⁴C-urea.
• 3.3. Urea concentrations are higher during metamorphic climax and at the end of metamorphosis than during prometamorphosis.
• 4.4. Blood ammonia levels remain rather constant throughout metamorphosis.
• 5.5. Coincidentally, the relative amount of urea in the blood increases.
• 6.6. The ¹⁴C-urea excretion rates slow down from very high values (48%/hr) at the beginning of prometamorphosis to low rates (5%/hr) in newly metamorphosed animals.
• 7.7. This means that during metamorphosis not only is the possibility of urea production established. but there is a capacity to retard and store urea to some extent.

     

Cloning and characterization of rabbit pancreatic colipase

• 1.1. Among the digestive enzymes synthesized by pancreas, lipase is the principle lipolytic enzyme which hydrolyses dietary glycerides.
• 2.2. For its action it requires a coenzyme, colipase.
• 3.3. The molecular mechanisms of the interaction of these two are not fully understood.
• 4.4. Further, molecular events that regulate and influence lipid absorption are ill denned.
• 5.5. The rabbit is the conventional animal model for the study of lipid absorption. We have undertaken the molecular cloning, and characterization of rabbit pancreatic colipase, the coenzyme for pancreatic lipase.
• 6.6. Colipase has been cloned from a gt 11 library of an adult rabbit pancreatic cDNA by probing with an oligonucleotide derived from human colipase sequence.
• 7.7. The total reading frame consists of 321 nucleotides coding for 90 amino acids of the functional protein and 17 nucleotides of the leader peptide.
• 8.8. Northern blot analysis revealed a distinct band around 0.5kb. Comparison with other species revealed an over all homology of 75% at the nucleotide level.
• 9.9. At the amino acid level highest conservation is observed at the lipase-binding region (AA 53–73).
• 10.10. Rabbit enzyme also retained the N-terminal pentapeptide of it preform.
• 11.11. The regions of homology and conservation may aid to define the sites of interaction of colipase with lipase.

     

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He partial sequencing of human nonspecific (bone/liver/kidney) alkaline phosphatase gene

• 1.1. A charon 4A human fetal liver genomic library was screened for human nonspecific alkaline phosphatase gene using the cloned human bone cDNA as a hybridization probe.
• 2.2. A clone 2.2 Kb DNA was sequenced and found to contain a piece of sequences encoding the 4–44th amino acids of NH; terminus.
• 3.3. The other cloned 1.6Kb DNA contains two segments of sequences each corresponding to two separate regions of the cDNA for alkaline phosphatase. The first segment of the DNA codes for the 83–141st amino acids whereas the second for 141–199th.