Cellular and Secretory Proteins of the Salivary Glands of \u3cem\u3eSciara coprophila\u3c/em\u3e During the Larval-pupal Transformation

The cellular and secretory proteins of the salivary gland of Sciara coprophila during the stages of the larval-pupal transformation were examined by electrophoresis in 0.6 mm sheets of polyacrylamide gel with both SDS-continuous and discontinuous buffer systems. After SDS-electrophoresis, all electrophoretograms of both reduced and nonreduced proteins from single glands stained with Coomassie brilliant blue revealed a pattern containing the same 25 bands during the stages of the larval-pupal transformation. With the staining procedures used in this study, qualitative increases and decreases were detected in existing proteins and enzymes. There was no evidence, however, for the appearance of new protein species that could be correlated with the onset of either pupation or gland histolysis. Electrophoretograms of reduced samples of anterior versus posterior gland parts indicated that no protein in the basic pattern of 25 bands was unique to either the anterior or posterior gland part. Electrophoretograms of reduced samples of secretion collected from either actively feeding or cocoon -building animals showed an electrophoretic pattern containing up to six of the 25 protein fractions detected in salivary gland samples, with varied amounts of these same six proteins in electrophoretograms of secretion samples from a given stage. Zymograms of non-specific esterases in salivary gland samples revealed a progressive increase in the amount of esterase reaction produce in one major band and some decrease in the second major band during later stages of the larval-pupal transformation

Evidence for Endoreduplication: Germ Cell DNA Levels Prior to Chromatin Diminution in Mesocyclops Edax

We studied the functional significance of marked differences in the DNA content of somatic cells and germ line nuclei by static Feulgen-DNA cytophotometry for several species of microcrustaceans that exhibit chromatin diminution during very early stages of embryogenesis. Mature females and males showed many gonadal nuclei with elevated amounts of DNA that persist until dispersal of this extra DNA throughout the cytoplasm as fragments and coalescing droplets of chromatin during anaphase of the diminution division

CYTOCHEMICAL STUDIES OF RNA AND BASIC NUCLEAR PROTEINS IN LYCOSID SPIDERS

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Genome Size and Endonuclear DNA Replication in Spiders

Although genome sizes (C-values) are now available for 115 arachnid species (Gregory and Shorthouse [2003] J Hered 94:285-290), the extent of genome amplification (endonuclear DNA replication or polyploidization) accompanying tissue differentiation in this diverse and abundant class of invertebrates remains unknown. To explore this aspect of arachnid development, samples of hemolymph and other tissues were taken from wild-caught specimens as air-dried smears, stained with the Feulgen reaction for DNA, and assayed using both scanning and image analysis densitometry. Cells from midgut diverticula and Malpighian tubules of Argiope and Lycosa (=Pardosa) often showed giant nuclei with 50-100 pg of DNA per nucleus, reflecting at least four cycles of endonuclear DNA replication when compared to the DNA content of hemocytes or sperm from the same specimen. Nuclei with markedly elevated DNA levels also appeared, but far less frequently, in tissue samples from several other arachnid species (Antrodiaetus, Hypochilus, Latrodectus, Liphistus and Loxosceles), but revealed no correlation with differences in somatic cell (2C) genome sizes. Our data show that several DNA classes of polysomatic nuclei regularly arise during tissue differentiation in some species of spiders and may provide an interesting model system for further study of patterns of tissue-specific variation in DNA endoreduplication during development

MICROSPECTROPHOTOMETRIC ANALYSIS OF MITOSIS AND DNA SNYTHESIS ASSOCIATED WITH COLONY FORMATION IN PEDIASTRUM BORYANUM (CHLOROPHYCEAE)

Patterns of DNA synthesis and mitosis in the coenobial alga Pediastrum boryanum (Turp.) Meneghini were analyzed by cytophotometric measurements of individual, Feulgen‐stained nuclei from swarming zoospores aggregating into colonies, and cells in colonies varying in age from 12 to 96 h after their initial transfer to fresh culture medium. A haploid genome size of 0.2 pg DNA (corresponding to roughly 11 × 1012 daltons, or 1.64 × 105 kb) was estimated by comparative measurements of nuclei from zoospores or young colonies and chicken erythrocyte (RBC) nuclei which were included with each set of Pediastrum slides as an internal reference standard of 2.5 pg DNA/cell. Although nuclear morphology and extent of chromatin condensation vary with different stages of colony development, nuclear division in P. boryanum appears to follow each cycle of DNA replication with no accumulation of DNA beyond the 2C level. Cytoplasmic cleavage resulting in the formation of individual zoospores is delayed until completion of mitosis, as is the demise of the pyrenoid. After 96 h of culture, 40% of all colonies have cells that are 8‐ or 16‐nucleate and some colonies have 32 nuclei/cell. Release of zoospores within vesicles occurs at this time to complete a cycle of asexual reproduction

Further Characterization of Female Sterile (1) 1304 Mutant of Drosophila Melanogaster

The Drosophila melanogastor mutant fs(1) 1304 (1‐19 ± 2) has been characterized using various experimental approaches. The mutant ap4 (2‐55.2), used as a control in some of the experiments reported in this paper, has also been examined more carefully. Electrophoresis of ovarian extracts from the mutants on polyacrylamide gels yield results suggesting that vitellogenesis is completely inhibited in ap4/ap4 females, while it proceeds at an abnormally slow rate in fs/fs females. Both mutants accumulate hemolymph proteins in amounts in excess of those found in the hemolymph of wild type females, suggesting that uptake of proteins from the hemolymph is affected by both the mutant genes. Qualitative differences in the banding patterns obtained from the hemolymph of wild type and ap4 female suggest that homozygous ap4 females may also be defective in the synthesis or processing of yolk proteins. Three of the protein bands observed in our electropherograms are suspected to represent yolk proteins, and an additional band is thought to represent an aggregate of the three yolk proteins. Neither juvenile hormone nor ecdysone treatment enhance vitellogenesis in fs(1)1304, although ap4 females produce yolky oocytes after JH treatment, in agreement with previously reported results. Ovarian transplantation studies suggest that fs(1)1304 behaves autonomously. Previous studies have shown that ap4 females behave non‐autonomously