The structure and evolution of the spider monkey delta-globin gene

We have isolated the delta-globin gene of the New-World spider monkey, Ateles geoffroyi, and compared its nucleotide sequence with those of other primate delta- and beta-globin genes. Among primate delta-globin genes, the rate of nonsynonymous substitutions is much less than the rate of synonymous substitutions. This suggests that primate delta- globin genes may remain under evolutionary conservation, perhaps because hemoglobin A2 has an as yet unknown physiological importance.      

Two Loci Controlling Genetic Cellular Resistance to Avian Leukosis-Sarcoma Viruses

Female chickens known to be heterozygous for resistance to subgroups A and B of the avian leukosis-sarcoma viruses were mated to males known to be homozygously resistant to both. The progeny were assayed both on the chorioallantoic membrane (CAM) and in tissue culture for resistance to representative viruses of the A, B, and tentatively defined C subgroups. Segregation ratios of resistance to A and B subgroup viruses agreed with the previously suggested hypothesis of single-autosomal-recessive genes controlling resistance to each subgroup. Mixed infection on the CAM and replicate plate infection in tissue culture with subgroup A and B viruses showed that resistance to the A and B subgroups was inherited independently. Assays with viruses tentatively classified as subgroup C indicated that they were largely composed of a mixture of subgroup A and B viruses or of particles possessing the host range specificity of both. However, virus stocks of the subgroup C category, as well as some stocks classified as subgroup B, produced small numbers of pocks or foci on individuals known to be resistant to subgroup A and B viruses. It is suggested that these Rous sarcoma virus stocks carry between 1 and 10% of a true subgroup C virus.     

The Fertility Effects of Pericentric Inversions in Drosophila Melanogaster

Heterozygotes for pericentric inversions are expected to be semisterile because recombination in the inverted region produces aneuploid gametes. Newly arising pericentric inversions should therefore be quickly eliminated from populations by natural selection. The occasional polymorphism for such inversions and their fixation among closely related species have supported the idea that genetic drift in very small populations can overcome natural selection in the wild. We studied the effect of 7 second-chromosome and 30 third-chromosome pericentric inversions on the fertility of heterokaryotypic Drosophila melanogaster females. Surprisingly, fertility was not significantly reduced in many cases, even when the inversion was quite large. This lack of underdominance is almost certainly due to suppressed recombination in inversion heterozygotes, a phenomenon previously observed in Drosophila. In the large sample of third-chromosome inversions, the degree of underdominance depends far more on the position of breakpoints than on the inversion's length. Analysis of these positions shows that this chromosome has a pair of ``sensitive sites' near cytological divisions 68 and 92: these sites appear to reduce recombination in a heterozygous inversion whose breakpoints are nearby. There may also be ``sensitive sites' near divisions 31 and 49 on the second chromosome. Such sites may be important in initiating synapsis. Because many pericentric inversions do not reduce the fertility of heterozyotes, we conclude that the observed fixation or polymorphism of such rearrangements in nature does not imply genetic drift in very small populations.     

Protection from oxygen-induced seizures by clonazepam and propylene glycol

General anesthetics, ganglionic blocking agents, anticonvulsants, and antioxidants have been shown to afford protection from seizures caused by exposure to hyperbaric oxygen. In the present study cats were exposed to 5 ATA oxygen in pairs in a hyperbaric chamber until both the control and pretreated cat convulsed or for a maximum 120 min exposure. Small amounts of four common antiepileptic agents and propylene glycol in amounts far less than previously reported (0.1 to 0.2 ml/kg) were initially tested for potential anticonvulsant activity. Two agents, clonazepam and propylene glycol, offered significant protection in delaying the onset of seizures whereas carbamazepine, valproic acid, and trimethadione appeared to hasten the onset of seizure activity. The time to seizures was increased nearly five times by clonazepam and over three times by very small amounts of propylene glycol.     

Analysis of antigenic determinants of structural polypeptides of avian type C tumor viruses.

Radioimmunoassays were developed for the 19,000, 15,000, and 12,000 molecular weight polypeptides of avian myeloblastosis virus and for the 19,000 and 12,000 polypeptides of RAV-0, a subgroup E avian tumor virus. Each polypeptide was shown to possess both group- and type-specific antigenic determinants, in contrast to the 27,000 mol wt polypeptide, which contained only group-specific determinants. The corresponding low-molecular-weight polypeptides of subgroup A, B, and E viruses were shown to be immunologically indistinguishable. The findings that low-molecular-weight polypeptides of subgroup C and D viruses reacted very differently in immunoassays for the respective polypeptides of avian myeloblastosis virus or RAV-0 suggest that subgroups C and D may have evolved differently form subgroups A, B, and E.     

Using dynamic pupillometry as a simple screening tool to detect autonomic neuropathy in patients with diabetes: a pilot study

Background  

Autonomic neuropathy is a common and serious complication of diabetes. Early detection is essential to enable appropriate interventional therapy and management. Dynamic pupillometry has been proposed as a simpler and more sensitive tool to detect subclinical autonomic dysfunction. The aim of this study was to investigate pupil responsiveness in diabetic subjects with and without cardiovascular autonomic neuropathy (CAN) using dynamic pupillometry in two sets of experiments.     

Translocation of 15N indicates nitrogen recycling in the mat-forming lichen Cladonia portentosa

Nitrogen translocation was measured in Cladonia portentosa during 2 yr growth in Scottish heathland. Translocation was predicted to occur if N is resorbed from senescent basal tissue and recycled within the thallus. (15)N was introduced into either the lower (TU thalli) or upper (TD thalli) 25 mm of 50-mm-long thalli as (15)N-NH(4) (+), (15)N-NO(3) (-) or (15)N-glycine. Labelled thalli were placed within intact lichen cushions, either upright (TU) or inverted (TD). Vertical distribution of label was quantified immediately following labelling and after 1 and 2 yr. Independently of the form of introduced label, (15)N migrated upwards in TU thalli, with new growth being a strong sink. Sink regions for (15)N during year 1 (including new growth) became sources of (15)N translocated to new growth in year 2. Upward migration into inverted bases was minimal in TD thalli, but was again marked in new growth that developed from inverted apices. Relocation of N to regions of growth could facilitate internal N recycling, a process postulated to explain the ecological success of mat-forming lichens.     

GLD-3 and control of the mitosis/meiosis decision in the germline of Caenorhabditis elegans

Germ cells can divide mitotically to replenish germline tissue or meiotically to produce gametes. In this article, we report that GLD-3, a Caenorhabditis elegans Bicaudal-C homolog, promotes the transition from mitosis to meiosis together with the GLD-2 poly(A) polymerase. GLD-3 binds GLD-2 via a small N-terminal region present in both GLD-3S and GLD-3L isoforms, and GLD-2 and GLD-3 can be co-immunoprecipitated from worm extracts. The FBF repressor binds specifically to elements in the gld-3S 3′-UTR, and FBF regulates gld-3 expression. Furthermore, FBF acts largely upstream of gld-3 in the mitosis/meiosis decision. By contrast, GLD-3 acts upstream of FBF in the sperm/oocyte decision, and GLD-3 protein can antagonize FBF binding to RNA regulatory elements. To address the relative importance of these two regulatory mechanisms in the mitosis/meiosis and sperm/oocyte decisions, we isolated a deletion mutant, gld-3(q741), that removes the FBF-binding site from GLD-3L, but leaves the GLD-2-binding site intact. Animals homozygous for gld-3(q741) enter meiosis, but are feminized. Therefore, GLD-3 promotes meiosis primarily via its interaction with GLD-2, and it promotes spermatogenesis primarily via its interaction with FBF.