Endless forms most stupid,icky, and small: The preponderance of noncharismatic invertebrates as integral to a biologically sound view of life

Big, beautiful organisms are useful for biological education, increasing evolution literacy, and biodiversity conservation. But if educators gloss over the ubiquity of streamlined and miniaturized organisms, they unwittingly leave students and the public vulnerable to the idea that the primary evolutionary plot of every metazoan lineage is “progressive” and "favors" complexity. We show that simple, small, and intriguingly repulsive invertebrate animals provide a counterpoint to misconceptions about evolution. Our examples can be immediately deployed in biology courses and outreach. This context emphasizes that chordates are not the pinnacle of evolution. Rather, in the evolution of animals, miniaturization, trait loss, and lack of perfection are at least as frequent as their opposites. Teaching about invertebrate animals in a “tree thinking” context uproots evolution misconceptions (for students and the public alike), provides a mental scaffold for understanding all animals, and helps to cultivate future ambassadors and experts on these little‐known, weird, and fascinating taxa.     

Smoking and Health

Although cigarette smoking is the number one public health problem in the United States, physicians have failed to take the lead either in convincing youngsters not to begin smoking or in aiding adults to quit smoking. To be most effective and convincing in combating the smoking epidemic, practicing physicians must have the same basic fund of knowledge about the short- and long-term consequences of smoking as they do about other commonly encountered medical problems. By acting on such knowledge and adopting a definite set of attitudes and activities in their offices and with patients, physicians can make a significant contribution to their patients and to the entire community in which they practice.     

cDNA structure of murine C4b-binding protein, a regulatory component of the serum complement system

A cDNA library representing total poly(A+) RNA from the livers of male B10.WR mice was screened with a 1097 base pair (bp) probe obtained from a partial human C4b-binding protein (C4BP) cDNA clone. Two cDNA clones were isolated, the largest of which was sequenced and found to be 1889 bp in length exclusive of the poly(A) tail. The predicted mouse C4BP polypeptide chain encoded by 1239 bp is 413 amino acid residues in length and has a calculated molecular weight of 45,281. The 370-nucleotide sequence upstream from the codon for the predicted amino terminus contains two possible in-phase translational start signals which yield leader sequences of 56 and 13 amino acid residues, respectively. The 3'-untranslated region is 277 bp long, and there are two potential overlapping poly(A) recognition signals, AATTAA and ATTAAAA, located 26 and 25 bp, respectively, upstream from the poly(A) tail; these are preceded by five other potential polyadenylation signals. Beginning at the amino terminus and continuing through to residue 358, there are six contiguous regions of internal homology, each about 60 amino acids in length. The carboxy-terminal 55 amino acid sequence shares no homology with the repeating units. Extensive homology was found with human C4BP at the amino acid level (61%) as well as at the nucleotide level for both the coding and 3'-untranslated regions. Significant differences, however, were observed between mouse and human C4BP.(ABSTRACT TRUNCATED AT 250 WORDS)     

Analysis of simian virus 40 chromosome-T-antigen complexes: T-antigen is preferentially associated with early replicating DNA intermediates

The fraction and DNA composition of simian virus 40 chromosomes that were complexed with large T-antigens (T-Ag) were determined at the peak of viral DNA replication. Simian virus 40 chromatin containing radiolabeled DNA was extracted by the hypotonic method of Su and DePamphilis (Proc. Natl. Acad. Sci. U.S.A. 73:3466-3470, 1976) and then fractionated by sucrose gradient sedimentation into replicating (90S) and mature (70S) chromosomes. Viral chromosomes containing T-Ag were isolated by immunoprecipitation with saturating amounts of either an anti-T-Ag monoclonal antibody or an anti—T-Ag hamster serum under conditions that specifically precipitated T-Ag protein from cytosol extracts. An average of 10% of the uniformly labeled DNA in the 90S pool and 7.5% in the 70S pool was specifically precipitated, demonstrating that under these conditions immunologically reactive T-Ag was tightly bound to only 8% of the total viral chromosomes. In contrast, simian virus 40 replicating intermediates (RI) represented only 1.2% of the viral DNA, but most of these molecules were associated with T-Ag. At the shortest pulse-labeling periods, an average of 72 ± 18% of the radiolabeled DNA in 90S chromosomes could be immunoprecipitated, and this value rapidly decreased as the labeling period was increased. Electron microscopic analysis of the DNA before and after precipitation revealed that about 55% of the 90S chromosomal RI and 72% of the total RI from both pools were specifically bound to T-Ag. Comparison of the extent of replication with the fraction of RI precipitated revealed a strong selection for early replicating DNA intermediates. Essentially all of the RI in the 70S chromosomes were less than 30% replicated and were precipitated with anti—T-Ag monoclonal antibody or hamster antiserum. An average of 88% of the 90S chromosomal RI which were from 5 to 75% replicated were immunoprecipitated, but the proportion of RI associated with T-Ag rapidly decreased as replication proceeded beyond 70% completion. By the time sibling chromosomes had separated, only 3% of the newly replicated catenated dimers in the 90S pool (<1% of the dimers in both pools) were associated with T-Ag. Measurements of the fraction of radiolabeled DNA in each quarter of the genome confirmed that T-Ag was preferentially associated with newly initiated molecules in which the nascent DNA was nearest the origin of replication. These results are consistent with a specific requirement for the binding of T-Ag to viral chromosomes to initiate DNA replication, and they also demonstrate that T-Ag does not immediately dissociate from chromosomes once replication begins. The biphasic relationship between the fraction of T-Ag—containing RI and the extent of DNA replication suggests either that 1 or 2 molecules of T-Ag remain stably bound until replication is about 70% completed or that 4 to 6 molecules of T-Ag are randomly released from each RI at a uniform rate throughout replication.     

Species identity of insect cell lines

Summary Three mosquito cell cultures designated as Suitor's clone ofAedes aegypti, Culiseta inornata, andAedes vexans were shown to be moth by immunological, karyological, and isozyme analyses. The cells reacted with rabbit antimoth serum but not rabbit antimosquito serum. Chromosome analyses indicated Lepidopteran rather than Dipteran morphology, and three isozyme systems were confirmative. Any one of these assays would be sufficient to indicate that contamination had occurred and could be used as a periodic check for identity of cell cultures. Morphology and growth characteristics are also valid criteria to distinguish between these particular orders of insect cells. These studies were supported by Grant CA-04953-12 from the National Cancer Institute; General Research Support Grant FR-5582 from the National Institutes of Health; and Grant-in-Aid Contract M-43 from the State of New Jersey. Recipient of Research Career Award 5-K3-16,749 from the National Institutes of Health.     

Local cerebral glucose utilization in the hippocampus of old rats

Summary The local cerebral glucose utilization (LCGU) was measured in the different areas and layers of the Ammon's horn and dentate gyrus of young adult (3 to 4-month-old) rats, and of 27-month-old rats with proven cognitive deficits. The LCGU was determined by quantitative [¹⁴C]2-deoxyglucose autoradiography. Compared to young animals, in the old rats the LCGU was significantly reduced by 12% to 15% in the oriens layers of CA1 and CA2, the pyramidal layers of the CA sectors 1–3, the radiatum and lacunosum-molecular layers of CA2 and CA3 and in the lucidum layer of CA3. The LCGU values of all the other layers of the Ammon's horn and the dentate gyrus did not differ significantly between young and old rats. The pattern of the LCGU reduction found in the old rats roughly resembles changes found after fimbra-fornix lesions or systemic administration of scopolamine, suggesting a functionally important deficit in the cholinergic innervation of the old rats' hippocampi.     

Floral expression of a gene encoding an E2-relatedubiquitin-conjugating protein from Arabidopsis thaliana

An Arabidopsis thaliana gene (UBC6) encoding a homologue to ubiquitin-conjugating enzymes has been isolated which is capable of encoding a protein of 183 amino acids of ca. 21 kDa. Northern analysis indicates that the gene is expressed in flowers, seeds and, to a somewhat lesser extent, in 10-day seedlings but not in mature leaves, callus and pre-flowering plants. This pattern of expression is confirmed using transgenic Arabidopsis plants containing a UBC6 promoter-GUS gene fusion construct. These plants displey GUS activity in mature anthers prior to dehiscence, in developing embryos, sepals and the style after pollination.     

Ferredoxin and Formyltetrahydrofolate Synthetase: Comparative Studies with Clostridium acidiurici, Clostridium cylindrosporum, and Newly Isolated Anaerobic Uric Acid-Fermenting Strains

Six strains of Clostridium acidiurici and three strains of C. cylindrosporum were isolated from soil samples by enrichment culture with uric acid as the source of carbon, nitrogen, and energy. The newly isolated strains were characterized by their spore morphology and the amounts of glycine and formate formed by the fermentation of uric acid. The strains were easily identified as belonging to one species or the other on the basis of spore morphology and formate production. The crystal properties and spectra of the native ferredoxins of all the strains isolated and the amino acid composition and partial carboxy-terminal sequence of all their apoferredoxins were determined. All the ferredoxins were tested for cross-reactivity with antiserum to C. acidiurici ferredoxin by microcomplement fixation. Five of the six C. acidiurici strains, which had ferredoxins with amino acid compositions identical to that from C. acidiurici, also showed immunological identity (immunological distance = 0.0). These results suggest sequence identity. The one strain with a different amino acid composition failed to show complete cross-reactivity. Two of the three C. cylindrosporum strains have ferredoxin amino acid compositions identical to that from C. cylindrosporum. The third strain had a minimum of five differences in sequence. All C. cylindrosporum strains had ferredoxins that differed considerably from C. acidiurici strains (minimum of eight to nine differences), and none of these ferredoxins cross-reacted with antisera to C. acidiurici ferredoxin. Antisera were prepared to formyltetrahydrofolate synthetase from C. acidiurici and C. cylindrosporum, and all possible comparisons were made by using immunodiffusion and microcomplement fixation. There is more intraspecies variation in the synthetases than in the ferredoxins; however, the results suggest considerable interspecies differences in both proteins. These results suggest a low degree of genomic relatedness between the two species, which contrasts sharply with their apparent high degree of phenotypic similarity.