New limit on the neutrinoless betabeta decay of 130Te

We report the present results of CUORICINO, a search for neutrinoless double-beta (0nu betabeta) decay of 130Te. The detector is an array of 62 TeO2 bolometers with a total active mass of 40.7 kg. The array is cooled by a dilution refrigerator shielded from environmental radioactivity and energetic neutrons, operated at approximately 8 mK in the Gran Sasso Underground Laboratory. No evidence for (0nu betabeta) decay was found and a new lower limit, T(1/2)(0nu) > or = 1.8 x 10(24) yr (90% C.L.) is set, corresponding to [m(nu)] < or = 0.2 to 1.1 eV, depending on the theoretical nuclear matrix elements used in the analysis.

Agmenellum quadruplicatum M.AquI, a novel modification methylase

The complete type II modification methylase of Agmenellum quadruplicatum was cloned in Escherichia coli as an R.Sau3A fragment of approximately 4.5 kilobases. The coding sequence was contained in a stretch of 1,156 base pairs which was organized into two parallel, partly overlapping open reading frames of 248 and 139 codons. In vivo complementation experiments showed that the synthesis of both predicted peptides was required for full methylase activity. The amino acid sequences were considerably similar to regions of other deoxycytidylate methylases.

Isolation and characterization of the modification methylase M . SinI

A sequence-specific modification methylase (M . SinI) was isolated and purified from Escherichia coli harboring a derivative of recombinant plasmid pSI4 (see accompanying manuscript: C. Karreman and A. de Waard, J. Bacteriol. 170:2527-2532, 1988), which contains a Salmonella infantis DNA insert. The enzyme uniquely methylates the internal deoxycytidylate residue in the nucleotide sequence GG(A/T)MeCC, thereby protecting DNA completely against cleavage by restriction endonuclease R . SinI or R . AvaII [GG(A/T)CC], and in part against cleavage by R . Sau96I (GGNCC).

Cloning and complete nucleotide sequences of the type II restriction-modification genes of Salmonella infantis

The complete type II restriction-modification system of Salmonella infantis was cloned in Escherichia coli as an R . Sau3AI fragment of 3,430 base pairs. The clone was shown to express the restriction endonuclease as well as the modification methylase. The nucleotide sequence of the above fragment showed two open reading frames of 461 and 230 codons in tail-to-tail orientation. These were shown to represent the modification methylase M . SinI and the restriction endonuclease R . SinI, respectively. The methylase M . SinI amino acid sequence revealed a considerable similarity to those of other deoxycytidylate methylases. In contrast, endonuclease R . SinI did not exhibit such a similarity to other restriction enzymes.

Isolation of a deoxycytidylate methyl transferase capable of protecting DNA uniquely against cleavage by endonuclease R.Aqu I (isoschizomer of Ava I)

A sequence-specific modification methylase (M.AquI) was isolated and purified from Agmenellum quadruplicatum (Synechococcus PCC 7002). This enzyme uniquely methylates the deoxycytidylate residue in the sequence *CYCGRG indicated by the asterisk. It was shown to protect DNA against cleavage by restriction endonucleases AvaI, SmaI and XhoI, which recognize the sequences CYCGRG, CCCGGG, and CTCGAG, respectively.

A new endonuclease recognizing the deoxynucleotide sequence CCNNGG from the cyanobacterium Synechocystis 6701

A new sequence-specific endonuclease from the cyanobacterium Synechocystis species PCC 6701 has been purified and characterized. This enzyme, SecI, is unique in recognizing the nucleotide sequence: 5' -CCNNGG-3' 3' -GGNNCC-5' and cleaves it at the position indicated by the symbol. Two other restriction endonucleases, SecII and SecIII, found in this organism are isoschizomers of MspI and MstII, respectively.

Isolation of cDNA clones for human adenosine deaminase

Clones encoding human adenosine deaminase (ADA) were isolated from a cDNA library made from the lymphoblastoid cell line MOLT-4. The isolation procedure was based on the selection of clones hybridizing with a radioactive probe complementary to an RNA preparation, which had been highly enriched in ADA-specific mRNA. The latter RNA preparation was obtained by size-fractionating MOLT-4 RNA and selecting fractions that were translatable into ADA. The assay for the presence of ADA in the in vitro translation products, was based on immunoprecipitation with a specific anti-ADA serum. The antiserum used was shown to precipitate a 42-kDal protein with the properties of ADA. Positive clones were further screened by means of hybrid-released in vitro translation assays. Two clones were obtained which were able to select mRNA that could be translated into a 42-kDal protein immunoprecipitable with the ADA-antiserum. By use of Southern blots containing DNA from somatic cell hybrids, one of these ADA cDNA clones was assigned to the human chromosome 20 known to contain the ADA gene.

Nostoc PCC7524, a cyanobacterium which contains five sequence-specific deoxyribonucleases

Five nucleotide sequence-specific deoxyribonucleases present in cell-free extracts of the filamentous cyanobacterium Nostoc PCC7524 have been purified and characterized. One of these enzymes, designated Nsp(7524)I cleaves at a new kind of nucleotide sequence, i.e. 5'-PuCATG Py-3'. The other four restriction enzymes in this organism, designated Nsp(7524)II, Nsp(7524)III, Nsp(7524)IV and Nsp(7524)V, are isoschizomers of enzymes which have been previously described. The cleavage site of Nsp(7524)II which is an isoschizomer of SduI was determined.

Gene organization of the transforming region of weakly oncogenic adenovirus type 7: the E1a region

The structures of adenovirus type 7 (Ad7) cytoplasmic RNAs transcribed from the leftmost 4.5% of the viral genome during lytic infection of KB cells have been determined. The E1a region was found to specify three differently spliced mRNAs (I, II and III) which have common 5' and 3' termini. mRNAs I and II are transcribed between identical initiation and termination codons and code for polypeptides of 28 kd and 24 kd, whose only difference is an internal sequence of 32 amino acids present in the 28-kd protein. Translation of mRNA III initiates at the same AUG codon as in mRNA I and II, but uses a different reading frame beyond the splice point; consequently, it terminates at an earlier stop codon and yields a 6.3-kd polypeptide. Cytoplasmic E1a RNA was used as a template for in vitro protein synthesis in a cell-free system and found to encode polypeptides with apparent molecular weights of 42 kd, 40 kd, and 11 kd.

Isolation and properties of beta-galactoside binding lectins of calf heart and lung

A soluble lectin which agglutinates trypsin-treated rabbit erythrocytes was purified from calf heart using affinity chromatography on asialofetuin-Sepharose. Its molecular weight was determined by gel filtration to be approximately 17,000. On polyacrylamide gel electrophoresis in sodium dodecyl sulfate, the predominant molecular species had a molecular weight of 9,000, suggesting that the lectin is a dimer. Binding studies performed with iodinated lectin revealed that neuraminidase-treated calf erythrocytes contained approximately 5 X 10(6) lectin binding sites per cell. Native calf and rabbit erythrocytes bound the lectin, but human and rat erythrocytes required neuraminidase and trypsin treatment, respectively, for lectin binding to occur. A number of saccharides, glycopeptides, and glycoproteins possess haptene inhibitory activity toward lectin binding to erythrocytes. The most potent of these have either galactose beta leads to galactose beta leads to, galactose beta N-acetylglucosamine beta leads to, or galactose beta leads to N-acetylglucosamine beta leads to sequences at their nonreducing termini. Lactose and galactose beta 1 leads to 3N-acetylgalactosamine are the next best haptenes. Finally, alpha-linked galactose residues and free galactose are very weak haptenes. The presences of a terminal sialic acid residue impairs haptene activity in all instances. Calf heart also contains a membrane-associated lectin which is very similar but not identical with the soluble lectin. A soluble beta-galactoside binding lectin was also isolated from calf lung. It has the same molecular size and subunit structure as the soluble heart lectin and is antigenically identical. In binding studies, the pattern of inhibition by various haptenes was the same for all three lectins.

Preparation and specificity of endonuclease IV induced by bacteriophage T4

Bacteriophage-T4-induced endonuclease IV suitable for DNA sequence analysis has been prepared by a modified and easily reproducible method. The specificity of T4-induced endonuclease IV has been investigated in order to verify whether this enzyme exhibits a single nucleotide recognition or a short sequence recognition. The 5'-terminal dinucleotides and 3'-terminal nucleotides of oligonucleotides released by T4-induced endonuclease IV from three single-stranded DNAs (from bacteriophages phiX174, fd, M 13) have been analysed. In different DNAs, 74-82% of the 5'-terminal dinucleotides end in 5'-deoxycytidylic acid; small but significant levels of several dinucleotides ending in 5'-deoxyadenylic acid, 5'-thymidylic acid and 5'-deoxyguanylic acid are also found. As far as 3'-terminal nucleotides are concerned all nucleotides are present with a large predominance of thymidylic acid. It is concluded that T4-induced endonuclease IV recognizes short nucleotide sequences like all other DNases investigated so far. The spectrum of such sequences is, however, very narrow.

Specificity of deoxyribonucleic acid transmethylase induced by bacteriophage T2. I. Nucleotide sequences isolated from tmicrococcus luteus DNA methylated in vitro

(Deoxyribonucleic acid from Micrococcus luteus was methylated in vitro in the presence of S-adenosyl-(14C methyl)methionine with a DNA methyltransferase purified from extracts of te. coli infected with bacteriophage T2. The labelled DNA was degraded by enzymatic and specific chemical methods and the resulting short oligonucleotides were separated and characterized. tthe analytical data permit the conclusion that the tdna transmethylase reacts specifically with N-G-A-T-C-N sequences in which it converts adenine to a 6-methyl-aminopurine residue.