Hectorella: A member of the betalain-suborderChenopodiineae of the orderCentrospermae

Roots ofHectorella caespitosa Hook. f. were induced to produce a red pigment which was shown to be a betalain and not an anthocyanin. These data indicate thatHectorella belongs to theChenopodiineae, the betalain suborder of theCentrospermae, and excludes alignment with the anthocyanin family theCaryophyllaceae.     

Caprine Arthritis-Encephalitis Virus Is Distinct from Visna and Progressive Pneumonia Viruses as Measured by Genome Sequence Homology

Competitive inhibition of hybridization between ¹²⁵I-labeled caprine arthritis-encephalitis viral RNA and homologous cDNA by heterologous viral RNA shows that the caprine retrovirus shares <20% genome sequence homology with visna and progressive pneumonia viruses. These viruses, however, are indistinguishable in immunodiffusion reactions involving the major structural protein (p28).     

Ovomucoid intervening sequences specify functional domains and generate protein polymorphism

Two thirds of the natural chicken ovomucoid gene has been sequenced, including all exons and the intron sequences surrounding all fourteen intron/ exon junctions. The junction sequences surrounding four of the introns are redundant; however, the sequences surrounding the other three introns contain no redundancies and thus the splicing sites at either end of these three introns are unambiguous. The splicing in all cases conforms to the GT-AG rule. The ovomucoid gene sequence around intron F can be used to predict the cause of an internal deletion polymorphism in the ovomucoid protein, which is an apparent error in the processing of the ovomucoid pre-mRNA. We also compare the structural organization of the ovomucoid gene with the ovomucoid protein sequence to examine theories of the evolution of ovomucoids as well as the origin of intervening sequences. This analysis suggests that the present ovomucoid gene evolved from a primordial ovomucoid gene by two separate intragenic duplications. Furthermore, sequence analyses suggest that introns were present in the primordial ovomucoid gene before birds and mammals diverged, about 300 million years ago. Finally, the positions of the introns within the ovomucoid gene support the theory that introns separate gene segments that code for functional domains of proteins and provide insight on the manner by which eucaryotic genes were constructed during the process of evolution.     

Ultrastructural comparison of smooth muscle from ovarian follicle and oviduct of the golden hamster

Summary Ultrastructural characteristics of smooth muscle taken from ovarian follicles and oviducts of hamsters are compared. Differences between the two muscle types are more quantitative than qualitative, thus confirming that follicular muscle is a true smooth muscle with no unique characteristics. While both muscle types contain 50–80 Å filaments, -glycogen deposits, and organelles characteristically found in smooth muscle, the oviductal cells have substantially more sacs, tubular structures, sarcoplasmic reticulum, and mitochondria. Another difference concerns the cellular junctions; the oviductal cells exhibit nexuses, whereas the follicular cells show desmosomelike junctions. Based on ultrastructural differences, follicular smooth muscle seems to be a relatively toneless muscle suited for short, infrequent contractions, whereas oviductal smooth muscle is probably involved in more active tonic contractions.Supported by an Institutional Research Grant from Texas Women's University, by NIH Grant HD 12988, and by the Department of Anatomy at Wright State University     

Steroid sulphatase levels in XX males,including observations on two affected cousins

Summary Quantitative assays of steroid sulphatase in XX males have shown that some individuals have two functional loci, and others only one. Two affected cousins, who cannot share the same X-chromosome, nevertheless have male levels of steroid sulphatase, suggesting functional abnormality of the X chromosome.The hypothesis is advanced that these and other unusual features of X-chromosome function in some XX males, could be explained if such cases were due to an autosomal mutation, exercising its effect by causing abnormal inactivation of a subterminal area of Xp which normally escapes the inactivation process.     

Heparin-inhibitable lectins: Marked similarities in chicken and rat

Extracts of young rat lung contain a heparin-inhibitable lectin that closely resembles one recently purified from chicken liver. Both lectins interact with heparin and N-acetyl-D-galactosamine, and were purified by gel filtration on Sepharose CL-2B followed by affinity chromatography on heparin-Sepharose. They both behave as high molecular weight aggregates that can be dissociated into two peptides with apparent molecular weights of 13,000 and 16,000 by gel electrophoresis in SDS. Samples of purified lectin contained up to 20% DNA by weight, and the degree of lectin aggregation and hemagglutination activity was greatly reduced by treatment with micrococcal nuclease without inhibiting heparin-binding activity. Association of lectin with DNA is an artifact of homogenization in high salt, since only 2% of the lectin is found associated with a purified nuclear fraction.     

Resting eggs, seasonal dynamics, and production of Bosmina longispina maritima (P. E. Muller) (Cladocera) in the northern Baltic proper

The seasonal dynamics and production of Bosmina longispina maritimawas studied both in the pelagic zone and bottom sediments ofthe northern Baltic proper in 1979. Resting eggs started tohatch in April–May, but the pelagic zone population didnot show signs of increase until August; this is typical forthe species in this area. Relatively few of those hatched inthe spring and early summer survived the low temperatures andlack of food below the thermocline. The population increasewas started with individuals hatched after the thermal stratificationweakened. From August until October the number of resting eggsin the sediment rose in direct response to their productionin the pelagic zone. A new hatching period began in October–November,but conditions in the pelagic zone were not suitable for theirfurther development. Such mistiming of hatching may, along withother factors, help to explain the large annual variations inthe productivity of B. longispina maritima in the Baltic. Sexualreproduction was found to be of relatively greater importancein the study area than in the areas where Bosmina reaches higherproductivity. This was assumed to be due to more intense selectionpressures in the prevailing conditions.     

Desensitization of the D-2 dopamine receptor and the β2-adrenoceptor in the intermediate lobe of the rat pituitary gland

A D-2 dopamine receptor and a β₂-adrenoceptor occur in the intermediate lobe of the rat pituitary gland (IL). Exposure of intact IL tissue to a D-2 agonist diminished the ability of dopaminergic agonists [but not 5′-guanylyl imidodiphosphate (Gpp(NH)p)] to inhibit adenylate cyclase activity. Conversely, exposure of intact IL tissue to a β-adrenergic agonist diminished the ability of a β-adrenergic agonist (but not forskolin) to stimulate adenylate cyclase activity. Treatment of ovariectomized rats with 17β-estradiol desensitizes the β₂-adrenoceptor but not the D-2 receptor. Desensitization of the IL catecholamine receptors is discussed within the framework of a previously published “working model” of these receptors.