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1

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Egg Deposition Behavior in the Haplodiploid Sawfly Athalia rosae ruficornis Jakovlev (Hymenoptera: Symphyta: Tenthredinidae) (1998)

Lee, J. M. ; Hashino, Y. ; Hatakeyama, M. ; [et al.]

Springer

Journal of insect behavior 11 (1998), S. 419-428

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ISSN: 1572-8889

Keywords: Hymenoptera ; Athalia rosae ; egg deposition behavior ; mating ; eye color mutation ; primary sex ratio

Source: Springer Online Journal Archives 1860-2000

Topics: Biology

Notes: Abstract The egg deposition behavior of the turnip sawfly, Athalia rosae (Hymenoptera: Symphyta), is described. Both unmated and mated females lay eggs individually inside of fresh young leaves of cruciferous plants. During an oviposition event, females exhibit a distinct pause in abdominal contractions just before the actual egg deposition act. Unmated females show a longer pause (11.31 s on average) than mated females (4.38 s on overall average). By employing an eye color mutation, the sex of the eggs laid by females was ascertained. Females mated once lay mostly fertilized (diploid female) eggs initially but begin to lay a considerable number of unfertilized (haploid male) eggs later in life. The laying of an unfertilized egg is associated with a longer pause (6.98 s on average) than the laying of a fertilized egg (3.76 s on average). These results are in contrast to previous reports on apocritan Hymenoptera, where the presence of a pause or a longer pause during oviposition was associated with the deposition of fertilized eggs rather than unfertilized eggs. The possibility that mated Athalia rosae females control fertilization and its implications for sex allocation strategies are discussed.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1023/A:1020958831972

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2

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Phosphorylation dependence of the initiation of productive transcription of balbiani ring 2 genes in living cells (1996)

Egyházi, E. ; Ossoinak, A. ; Pigon, A. ; [et al.]

Springer

Chromosoma 104 (1996), S. 422-433

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ISSN: 1432-0886

Source: Springer Online Journal Archives 1860-2000

Topics: Biology , Medicine

Notes: Abstract Using polytene chromosomes of salivary gland cells of Chironomus tentans, phosphorylation state-sensitive antibodies and the transcription and protein kinase inhibitor 5,6-dichloro-1-β-d-ribofuranosyl-benzimidazole (DRB), we have visualized the chromosomal distribution of RNA polymerase II (pol II) with hypophosphorylated (pol IIA) and hyperphosphorylated (pol IIO) carboxyl-terminal repeat domain (CTD). DRB blocks labeling of the CTD with 32Pi within minutes of its addition, and nuclear pol IIO is gradually converted to IIA; this conversion parallels the reduction in transcription of protein-coding genes. DRB also alters the chromosomal distribution of IIO: there is a time-dependent clearance from chromosomes of phosphoCTD (PCTD) after addition of DRB, which coincides in time with the completion and release of preinitiated transcripts. Furthermore, the staining of smaller transcription units is abolished before that of larger ones. The staining pattern of chromosomes with anti-CTD antibodies is not detectably influenced by the DRB treatment, indicating that hypophosphorylated pol IIA is unaffected by the transcription inhibitor. Microinjection of synthetic heptapeptide repeats, anti-CTD and anti-PCTD antibodies into salivary gland nuclei hampered the transcription of BR2 genes, indicating the requirement for CTD and PCTD in transcription in living cells. The results demonstrate that in vivo the protein kinase effector DRB shows parallel effects on an early step in gene transcription and the process of pol II hyperphosphorylation. Our observations are consistent with the proposal that the initiation of productive RNA synthesis is CTD-phosphorylation dependent and also with the idea that the gradual dephosphorylation of transcribing pol IIO is coupled to the completion of nascent pol II gene transcripts.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00352266

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3

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Phosphorylation dependence of the initiation of productive transcription of Balbiani ring 2 genes in living cells (1996)

Egyházi, E. ; Ossoinak, A. ; Pigon, A. ; [et al.]

Springer

Chromosoma 104 (1996), S. 422-433

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ISSN: 1432-0886

Source: Springer Online Journal Archives 1860-2000

Topics: Biology , Medicine

Notes: Abstract. Using polytene chromosomes of salivary gland cells of Chironomus tentans, phosphorylation state-sensitive antibodies and the transcription and protein kinase inhibitor 5,6-dichloro-1-β-d-ribofuranosylbenzimidazole (DRB), we have visualized the chromosomal distribution of RNA polymerase II (pol II) with hypophosphorylated (pol IIA) and hyperphosphorylated (pol II0) carboxyl-terminal repeat domain (CTD). DRB blocks labeling of the CTD with 32Pi within minutes of its addition, and nuclear pol II0 is gradually converted to IIA; this conversion parallels the reduction in transcription of protein-coding genes. DRB also alters the chromosomal distribution of II0: there is a time-dependent clearance from chromosomes of phosphoCTD (PCTD) after addition of DRB, which coincides in time with the completion and release of preinitiated transcripts. Furthermore, the staining of smaller transcription units is abolished before that of larger ones. The staining pattern of chromosomes with anti-CTD antibodies is not detectably influenced by the DRB treatment, indicating that hypophosphorylated pol IIA is unaffected by the transcription inhibitor. Microinjection of synthetic heptapeptide repeats, anti-CTD and anti-PCTD antibodies into salivary gland nuclei hampered the transcription of BR2 genes, indicating the requirement for CTD and PCTD in transcription in living cells. The results demonstrate that in vivo the protein kinase effector DRB shows parallel effects on an early step in gene transcription and the process of pol II hyperphosphorylation. Our observations are consistent with the proposal that the initiation of productive RNA synthesis is CTD-phosphorylation dependent and also with the idea that the gradual dephosphorylation of transcribing pol II0 is coupled to the completion of nascent pol II gene transcripts.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00352266

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4

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Mn K-Edge X-Ray Absorption Spectroscopic Study of Mn-Doped Zn2SiO4 Phosphors (1999)

Choi, Y. G. ; Kim, K. H. ; Sohn, K. S. ; [et al.]

Springer

Journal of materials science 18 (1999), S. 621-624

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ISSN: 1573-4811

Source: Springer Online Journal Archives 1860-2000

Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1023/A:1006698918579

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5

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HMDC crosslinking of bovine pericardial tissue: a potential role of the solvent environment in the design of bioprosthetic materials (1995)

Naimark, W. A. ; Pereira, C. A. ; Tsang, K. ; [et al.]

Springer

Journal of materials science 6 (1995), S. 235-241

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ISSN: 1573-4838

Source: Springer Online Journal Archives 1860-2000

Topics: Medicine , Technology

Notes: Abstract The need for alternative crosslinking techniques in the processing of bioprosthetic materials is widely recognized. While glutaraldehyde remains the most commonly used crosslinking agent in biomaterial applications there is increasing concern as to its biocompatibility-principally due to its association with enhanced calcification, cytotoxicity, and undesirable changes in the mechanical properties of bioprosthetic materials. Hexamethylene diisocyanate (HMDC), like glutaraldehyde, is a bifunctional molecule which covalently bonds with amino groups of lysine residues to form covalent crosslinks. Evidence within the literature indicates HMDC-treated materials are less cytotoxic than glutaraldehyde-treated materials; however, there is limited characterization of the material properties of HMDC-treated tissue. This study uses a multi-disciplined approach to characterize the mechanical, thermal, and biochemical properties of HMDC-treated bovine pericardial tissue. Further, to facilitate stabilization of the HMDC reagent, non-aqueous solvent environments were investigated. HMDC treatment produced changes in mechanical properties, denaturation temperature, and enzymatic resistance consistent with crosslinking similar to that seen in glutaraldehyde treated tissue. The significantly lower extensibility and stiffness observed under low stresses may be attributed to the effect of the 2-propanol solvent environment during crosslinking. While the overall acceptability of HMDC as a crosslinking agent for biomaterial applications remains unclear, it appears to be an interesting alternative to glutaraldehyde with many similar features.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00146862

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6

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Crosslinking of tissue-derived biomaterials in 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDC) (1996)

Lee, J. M. ; Edwards, H. H. L. ; Pereira, C. A. ; [et al.]

Springer

Journal of materials science 7 (1996), S. 531-541

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ISSN: 1573-4838

Source: Springer Online Journal Archives 1860-2000

Topics: Medicine , Technology

Notes: In contrast to bifunctional reagents such as glutaraldehyde or polyfunctional reagents such as polyepoxides, carbodiimides belong to the class of zero-length crosslinkers which modify amino acid side-groups to permit crosslink formation, but do not remain as part of that linkage. The authors have compared the effects of 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDC) and glutaraldehyde (the de facto industrial standard crosslinker) on the hydrothermal, biochemical, and uniaxial mechanical properties of bovine pericardium. EDC crosslinking was optimized for maximum increase in collagen denaturation temperature using variables of pH, concentration, and ratio of EDC to N-hydroxysuccinimide (NHS): a reagent for formation of activated esters. EDC and glutaraldehyde crosslinked materials were subjected to hydrothermal denaturation tests, biochemical degradation by enzymes (collagenase, trypsin) and CNBr, amino acid analysis for unreacted lysine, and to high strain rate mechanical tests including: large deformation stress-strain studies (0.1 to 10 Hz), stress relaxation experiments (loading time 0.1 s) and small deformation forced vibration (1 and 10 Hz). A protocol for EDC crosslinking was developed which used 1.15% EDC (2:1 EDC:NHS) at pH 5.5 for 24 h. The increase in denaturation temperature for EDC (from 69.7±1.2°C to 86.0±0.3°C) was equivalent to that produced by glutaraldehyde (85.3±0.4°C). Both treatments equivalently increased resistance to collagenase and CNBr degradation; however, after denaturation, the EDC-treated tissue was slightly more resistant to collagenase, and markedly more resistant to trypsin. EDC-treated materials were more extensible and more elastic than glutaraldehyde-treated materials. Despite the differences in crosslinking mechanism, EDC and glutaraldehyde-treated materials are very similar. Subtle but intriguing differences in biochemical structure remain to be investigated.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00122176

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