Acoustically-orienting parasitoids in calling and silent males of the field cricket Teleogryllus oceanicus

Abstract.

• 1 On three Hawaiian Islands, the introduced Australasian field cricket Teleogryllus oceanicus Le Guillou (Orthoptera: Gryllidae) was found to be attacked by the phonotactic parasitoid tachinid fly, Ormia ochracea Bigot.
• 2 Noncalling males occurred with callers in all locations, but silent males were more heavily parasitized than callers.
• 3 Body size was unrelated to both calling status and the likelihood of harbouring parasitoid larvae.
• 4 An experiment examining the likelihood of calling in the laboratory by males collected as silent or calling individuals showed no difference between the two classes of males, after accounting for parasitoid levels; males harbouring larvae were less likely to call.

     

Nucleolar localization of an isoform of the IGF-I precursor

Background  

Alternative exons encode different isoforms of the human insulin-like growth factor-I (IGF-I) precursor without altering mature IGF-I. We hypothesized that the various IGF-I precursors may traffic IGF-I differently. Chimeric IGF-I precursors were made with green fluorescent protein (GFP) cloned between the signal and mature IGF-I domains.     

Similarity of the structure of DNA from a variety of sources

DNA's from diverse cells of different species and from diverse tissues give the same x-ray diffraction pattern. The presently observable structure of DNA appears, then, to be the same in all cells. Thus, DNA in the resting state-the stored genetic material, from sperm of Paracentrotus lividus, Arbacia lixula, and salmon and from T(2) and T(7) bacteriophage-gives a pattern indistinguishable from DNA from very rapidly dividing cells, e.g., human acute leukemic leukocytes, human leukemic myeloid cells, mouse sarcoma 180, and bacteria-E. coli and pneumococci-during their logarithmic growth. The same x-ray patterns are given by DNA's from more slowly dividing tissues, e.g. calf liver, calf thymus, and human normal and leukemic lymphatic tissue. DNA from chicken erythrocytes-a DNA presumably metabolically inert-gives a similar picture. DNA's from several sources with a wide range in nitrogen base ratios, prepared independently by different workers using various methods, have given final products in varying yield; these all gave the same x-ray pattern, suggesting that all DNA is in the double-helical configuration. Finally, separation of the DNA molecule into a number of fractions with a varying adenine + thymine:guanine + cytosine ratio, but a constant adenine:thymine and guanine:cytosine ratio, each giving the same x-ray pattern as the original whole molecule, suggests that DNA cannot exist in significant amounts in forms other than the double-helix. X-ray diffraction photographs of sperm heads, extracted nucleoprotamine, calf thymus nuclei and extracted nucleohistone, and of chicken erythrocyte nuclei, are not all as well defined as those given by extracted DNA, but it is clear from the general characteristics of the pattern that much of the DNA bound to protein in these nuclei has the usual helical configuration, and that the double-helical structure of DNA exists in the cell and is not an artifact.     

Effects of age,replicative lifespan and growth rate of human nucleus pulposus cells on selecting age range for cell-based biological therapies for degenerative disc diseases

Autologous disc cell implantation, growth factors and gene therapy appear to be promising therapies for disc regeneration. Unfortunately, the replicative lifespan and growth kinetics of human nucleus pulposus (NP) cells related to host age are unclear. We investigated the potential relations among age, replicative lifespan and growth rate of NP cells, and determined the age range that is suitable for cell-based biological therapies for degenerative disc diseases. We used NP tissues classified by decade into five age groups: 30s, 40s, 50s, 60s and 70s. The mean cumulative population doubling level (PDL) and population doubling rate (PDR) of NP cells were assessed by decade. We also investigated correlations between cumulative PDL and age, and between PDR and age. The mean cumulative PDL and PDR decreased significantly in patients in their 60s. The mean cumulative PDL and PDR in the younger groups (30s, 40s and 50s) were significantly higher than those in the older groups (60s and 70s). There also were significant negative correlations between cumulative PDL and age, and between PDR and age. We found that the replicative lifespan and growth rate of human NP cells decreased with age. The replicative potential of NP cells decreased significantly in patients 60 years old and older. Young individuals less than 60 years old may be suitable candidates for NP cell-based biological therapies for treating degenerative disc diseases.     

Short-wavelength sensitive opsin (SWS1) as a new marker for vertebrate phylogenetics

Background  

Vertebrate SWS1 visual pigments mediate visual transduction in response to light at short wavelengths. Due to their importance in vision, SWS1 genes have been isolated from a surprisingly wide range of vertebrates, including lampreys, teleosts, amphibians, reptiles, birds, and mammals. The SWS1 genes exhibit many of the characteristics of genes typically targeted for phylogenetic analyses. This study investigates both the utility of SWS1 as a marker for inferring vertebrate phylogenetic relationships, and the characteristics of the gene that contribute to its phylogenetic utility.