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K Grzelak

Publications and source records attributed to K Grzelak.

14 recordsLinked to original sources
PubMed2006

Observation of muon neutrino disappearance with the MINOS detectors in the NuMI neutrino beam.

This Letter reports results from the MINOS experiment based on its initial exposure to neutrinos from the Fermilab NuMI beam. The rates and energy spectra of charged current nu(mu) interactions are compared in two detectors located along the beam axis at distances of 1 and 735 km. With 1.27 x 10(20) 120 GeV protons incident on the NuMI target, 215 events with energies below 30 GeV are observed at the Far Detector, compared to an expectation of 336+/-14 events. The data are consistent with nu(mu) disappearance via oscillations with |Delta(m)2/32|=2.74 +0.44/-0.26 x10(-3)eV(2) and sin(2)(2theta(23))>0.87 (68% C.L.).

Journal Article↗
PubMed2001

Expression of larval hemolymph proteins (Lhp) genes and protein synthesis in the fat body of greater wax moth (Galleria mellonella) larvae during diapause.

When one-day-old, last instar Galleria mellonella larvae are exposed to 18 degrees C they enter diapause and cease further development for several months. During diapause a group of proteins (72-84 kDa) synthesized in the fat body and secreted into the hemolymph is markedly elevated. Partial sequencing of the N-terminus of two proteins from this group confirmed their identity with larval hemolymph proteins (LHP) belonging to the family of hexameric storage proteins. The expression of two Lhp genes of known sequence (Lhp76 and Lhp82) were monitored in both diapausing and non-diapausing individuals. The expression of both genes and subsequent synthesis of the proteins (LHP76 and LHP82) is maintained until at least 90-100 days of diapause.

Journal Article↗
PubMed1996

Influence of low temperature on the synthesis of some Galleria mellonella proteins.

In developing Galleria mellonella larvae (reared at 30 degrees C) three proteins of 74, 76 and 81/82 kDa were identified. They represent a group of storage proteins (LHP proteins). In Galleria larvae, the development of which is arrested by low temperature (18 degrees C), accumulation of the 74, 76 and 81/82 kDa proteins was detected in the hemolymph. The synthesis of 74 kDa and 76 kDa proteins started after 24 h, and that of about 80 kDa after 96 h following the transfer of larvae from 30 degrees C to 18 degrees C. 20-Hydroxyecdysone inhibited synthesis of the 74 and 76 kDa proteins in larvae exposed to low temperature. The arrest of development of Galleria larvae is associated with the synthesis and accumulation of storage proteins, and ecdysteroids are involved in these processes.

Animals↗
PubMed1995

Control of expression of silk protein genes.

At least three silk genes are specifically expressed in the posterior, and five other genes in middle, silk glands. The products of genes active in PSG include fibroin, L-chain fibroin and P25 protein. PSG genes as well as the Ser-1 gene, differing in structure, exhibit a striking degree of homology of their 5' flanking sequences. This suggests the presence of common regulatory mechanisms. The expression of silk protein genes is probably controlled by tissue-specific and general transcriptional factors. Hormones seem to participate in the regulation of expression of silk protein genes.

Animals↗
PubMed1994

Nucleotide sequence, structure and developmental regulation of LHP82, a juvenile hormone-suppressible hexamerin gene from the waxmoth, Galleria mellonella.

We cloned and sequenced a composite cDNA corresponding to the 2.6 kb last instar-specific, juvenile hormone-suppressible Lhp82 mRNA from Galleria mellonella. The identity of the cDNA was confirmed by N-terminal amino acid sequencing of the purified Lhp82 subunit. In addition, we sequenced all coding regions and most of the intronic DNA as well as 1300 nucleotides of 5' flanking DNA from the Lhp82 gene. The eight exons of the Lhp82 gene specify a pre-protein of 706 residues, including the signal peptide of 18 amino acids. The deduced amino acid sequence of Lhp82 contains four potential N-glycosylation sites, and the calculated isoelectric point and molecular weight of secreted Lhp82 are pI = 6.43 and 79.9 kDa, respectively. Inspection of the 5' flanking and intronic regions of Lhp82 DNA revealed a 301 nucleotide cassette in intron 6 that appears to be a recently inserted repetitive element. We also performed Northern blot and nuclear run-off transcription experiments in order to determine the basis for Lhp82 gene inactivity after day 2 of the pupal stage. The results of these studies indicate that Lhp82 transcription is permanently shut off by the ecdysteroid pulse which occurs in the absence of juvenile hormone beginning 24 h post-pupation.

Amino Acid Sequence↗
PubMed1991

Hormonal regulation of protein synthesis in the silk gland of Galleria mellonella.

Synthesis of the low molecular mass silk proteins of 24 and 30 kDa in the last larval instar of Galleria mellonella starts between 24 and 48 h; synthesis of the former protein significantly preceding that of the latter. Posterior silk glands (PSG) from day-1 last instar larvae are transiently sensitive in vitro to exogenous 20-hydroxyecdysone (20-HE), which stimulates transcription of the 24 kDa protein gene and induces transcription of the gene for the 30 kDa protein. The glands from the day -3 last instar larvae are insensitive to this hormone. The brain extract acts directly on RNA synthesis in silk gland in vitro at the concentration of 0.1 brain equivalent per gland. This factor is protease sensitive and thermostable.

Animals↗
PubMed1982

Stimulation of RNA transcription by juvenile hormone in degenerating silk glands.

RNA transcription in the silk glands of the wax moth, Galleria mellonella, decreases during cocoon spinning and particularly later in pharate pupae, when the glands begin to degenerate. Application of juvenile hormone to insects at those developmental stages enhances synthesis of polyadenylated RNA 4-6 times and to lesser extent synthesis of total RNA. The newly formed poly(A)RNA appears identical with that from the normally fully functioning and silk-producing glands: it contains the same predominant poly(A)RNA class and is equally readily translated in the wheat-germ system. The results indicate that the hormone restores the function of silk glands at the transcriptional level.

Animals↗