The ventromedial nucleus of the hypothalamus and the hormonal arousal of sexual behaviors in the female rat

Bilateral lesions of the ventromedial nucleus of the hypothalamus interfered with the estrogenic induction of sexual receptivity in the female rat, but seemingly did not affect the ability of female rats to show lordosis following combined stimulation with estrogen and progesterone. In addition, ventromedial hypothalamic lesions did not affect the ability of females to show male-like sexual activity in response to exogenous androgenic stimulation.     

Labeling of glucagon binding components in hepatocyte plasma membranes.

A photosensitive derivative of glucagon, ¹²⁵I-N^?-4-azido-2-nitrophenyl-glucagon, has been synthesized and used to specifically label glucagon binding proteins in hepatocyte plasma membranes. Photolysis of the derivative in the presence of a membrane suspension results in the incorporation of radioactivity primarily into membrane components with a molecular weight range of 23,000–25,000. The binding properties of the derivative are essentially identical to that observed for glucagon. The binding of ¹²⁵I-NAP-glucagon was completely inhibited in the presence of glucagon (3 μM) while greater than 90% of the covalent labeling was also inhibited in the presence of glucagon. These studies suggest that the labeled membrane protein may be a component of the glucagon receptor.     

Studies on the mode of action of calciferol: Biological activity of 1α,24R,25-trihydroxyvitamin D3 in the chick

The biological activity of 1α,24R,25-trihydroxyvitamin D₃ [1α,24R,25(OH)₃D₃] was elevated in comparison to the hormonally active form of vitamin D₃, 1α,25-dihydroxyvitamin D₃ [1α,25(OH)₂D₃], in the rachitic chick in terms of its ability to (a) stimulate intestinal calcium absorption, (b) mobilize bone calcium, (c) induce intestinal calcium binding protein, (d) modulate the level of enzyme activity of the renal 25-OH-D₃-1-hydroxylase system, and (e) interact with the intestinal cystosol-chromatin receptor system for the 1α,25(OH)₂D₃ receptor system. In each of these assays, the relative ratio of activity of 1α,24R,25(OH)₃D₃ to 1α,25(OH)₂D₃was (a) 25–50, (b) ca. 20, (c) 10, (d) 50, and (e) 36%, respectively.     

Morphine and Cocaine Exert Common Chronic Actions on Tyrosine Hydroxylase in Dopaminergic Brain Reward Regions

We studied levels of tyrosine hydroxylase immunoreactivity and phosphorylation state in the ventral tegmental area (VTA) and nucleus accumbens (NAc) in an effort to understand better the mechanisms by which these brain reward regions are influenced by opiates and cocaine. In the VTA, chronic, but not acute, administration of either morphine or cocaine increased levels of tyrosine hydroxylase immunoreactivity by 30-40%, with no change observed in the relative phosphorylation state of the enzyme. In the NAc, chronic, but not acute, morphine and cocaine treatments decreased the phosphorylation state of tyrosine hydroxylase, without a change in its total amount. In contrast, morphine and cocaine did not regulate tyrosine hydroxylase in the substantia nigra or caudate/putamen, brain regions generally not implicated in drug reward. Morphine and cocaine regulation of tyrosine hydroxylase could represent part of a common biochemical basis of morphine and cocaine addiction and craving.     

Arboriculture in the Mussau Islands,Bismarck Archipelago

The Mussau Islanders of the Bismarck Archipelago in northeastern Papua New Guinea cultivate 26 indigenous tree species both for food and non-food uses in tree gardens surrounding the villages. Several trees which volunteer in these arboriculture zones are also tended and encouraged. I present ethnobotanical information on methods of cultivation, how and when the trees are harvested, preparation and use. The tree crop zone has a random spatial distribution overall, but some species within the zone are aggregated spatially. This clumping is related to the restricted habitat requirements of certain species, as well as individual species ’ reproductive traits. Coconut is the most frequent species in the arboriculture zone and is randomly distributed. Vertical stratification is attributable to the presence of a distinct herb layer and a subcanopy stratum of maturePandanus spp. The stratification of some species pairs results from the deliberate planting of subcanopy trees next to canopy trees. The introduction of exotic garden species and the increasing availability of western packaged foods is changing the composition of traditional Mussau Islands tree gardens.     

Artemia monica cyst production and recruitment in Mono Lake,California, USA

Annual egg production was determined for Artemia monica in Mono Lake, California, from 1983 to 1987. Annual oviparous (overwintering cyst) production was 3 and 7 million cysts m^–2 yr^–1 in 1986 and 1987, respectively, as measured by in situ sediment traps. Cyst production for the entire five year period was calculated using Artemia census data and inter-brood duration derived from mixolimnetic temperature. These estimates ranged from 2 to 5 million cysts m^–2 yr^–1. This method underestimated annual production by 30%, when compared to estimates using sediment traps. Cyst production was similar during 1983–1986 and showed a significant increase in 1987, which was due primarily to a larger reproductive population later in the year. Recruitment into the adult populations of the following spring ranged between 1.4 to 3.2%. Overall abundance of this generation reflected the patterns in annual cyst production. Compensatory effects must operate on the second generation of each year, since summer populations were similar in all years despite differences in cyst production.     

Structure of tendon organs in fishes of the genus Polymixia

Summary Modified branchiostegal rays 1 through 3 support the proximal end of the paired hyoid barbels in the beardfish (Beryciformes: Polymixiidae). The polymixiid barbel is unusual in that it has an unique intrinsic muscular system. Using silver impregnation and electron microscopic techniques, unencapsulated, free nerve endings were located within the tendon of the third modified branchiostegal ray. Branchiostegal rays 1 and 2 do not have any free nerve endings associated with their tendons, however. It is suggested that the free nerve endings are proprioceptors acting as stretch-sensitive mechanoreceptors, and that branchiostegal ray 3 acts as part of a sensory apparatus for monitoring the positional state of the barbel. Branchiostegal rays 1 and 2 merely provide support for the barbel.Abbreviations used in Figures BA barbel - br r 3 branchiostegal ray 3 - IM intermandibularis - IOP interoperculum - LIM interoperculomandibular ligament - MD mandible - MX maxilla - OP operculum - PM premaxilla - POP preoperculum - SOP suboperculum     

Transposition of the kanamycin-resistance transposon Tn903

Summary The insertion of the kanamycin-resistance transposon, Tn903, into the Escherichia coli chromosome was studied. Tn903 is similar in structure to the well known transposons Tn5 and Tn10 in that it has a unique central sequence flanked by inverted repeat sequences extending more than a thousand base pairs. However, the central region of Tn903 has enough single-frame coding capacity only for the drug modifying enzyme, whereas Tn5 and Tn10 carry multigenic unique sequences. In this paper we demonstrate that two different classes of insertion event occur: (1) the first class is a complex event in which all or part of the genome of the bacteriophage lambda vector is co-inserted near the purE locus on the E. coli chromosome (11.7 min); (2) the second class appears to be a simple transposition event in which the transposon alone is inserted at relatively nonspecific sites in the chromosome, as has been described for Tn5 and Tn10. Furthermore both classes show dependency on homology-requiring recombination systems. We suggest that Tn903 transposes infrequently because it must utilize a recA-controlled host function, whereas Tn5 and Tn10 are recA-independent and encode similar but more active functions on the transposon DNA.     

Lectin induction of lymphokines in cultured murine leukocytes

Antigens induce sensitized lymphocytes to undergo mitosis and to secrete soluble products, termed lymphokines, which modulate the immune response. Plant lectins are known to act as polyclonal lymphocyte mitogens and, in some cases, stimulate lymphocytes to produce lymphokines. In an effort to explore the relationship of specific cell surface glycoconjugates to the induction of mitosis and the production of lymphokine activities we have examined the ability of the mitogenic lectins, concanavalin A and Wistaria floribunda mitogen, and the nonmitogenic hemagglutinin from Wistaria floribunda seeds to stimulate the production of macrophage migration inhibition factor (MIF), macrophage chemotactic factor (CF), and lymphotoxin (LT). Concanavalin A causes lymphocytes to produce MIF and LT but no detectable CF activities. W. floribunda mitogen induces lymphocytes to produce soluble substances which exhibit all three lymphokine activities. The nonmitogenic W. floribunda agglutinin causes lymphocytes to produce MIF and CF but no observable LT activity. Within the sensitivity of the assays employed, the results indicate that mitogenesis is not a corequisite of the expression of either macrophage migration inhibition factor or lymphocyte-derived chemotactic factor but it may be associated with the induction of lymphotoxin. It is also apparent that the expression of each lymphokine activity is independent of the expression of the other lymphokines studied.     

Systematic studies of Pinus balfouriana based on volatile terpenoids from wood and needles and on seed morphology

Essential oil from wood and from needles of Pinus balfouriana, growing in six geographically well-separated locations in California, was analysed by GLC. Several monoterpenoid components, in particular -pinene from needles, were found to be usable for distinguishing between trees from the northern and southern parts of the geographic range. Similarity coefficients were calculated and dendrograms constructed. These demonstrated the distinct separation of the northern from the southern populations, and thus substantiated the proposal by Mastrogiuseppe to regard the southern populations as a subspecies. While the northern populations exhibited a tendency to produce larger seeds with longer wings, the difference was of only moderate diagnostic value.