Interindividual distance and influence of dominance on feeding in a natural Japanese macaque troop

In a natural troop of Japanese macaques (Macaca fuscata yakui), the dominant-subordinate relationship restricted the feeding behavior of the subordinate in two ways: (1) the dominant drives away the subordinate through agonistic interactions; and (2) the subordinate avoids approaching the dominant without any agonistic interactions. These occurred only infrequently, and only when an interindividual distance was less than a certain distance, which is called the “tolerance/intolerance” (T/I) distance. On the other hand, the usual interindividual distance when feeding was much greater than the T/I distance. Therefore dominance has little influence on feeding in the study troop. In the study troop, the T/I distance between kin-related females was shorter than that between unrelated individuals. Although this difference may facilitate kin selection if the troop faces severe competition over concentrated food, the difference does not seem to influence survival or reproductive rate in the study troop.     

Adenosine 3′,5′-Cyclic Monophosphate-Deficient Mutants of Vibrio cholerae

Two adenosine 3',5'-cyclic monophosphate (AMP)-deficient mutants of Vibrio cholerae (biotype El Tor) were successfully isolated by nitrosoguanidine treatment followed by pencillin screening for pleiotropic sugar-negative clones. Exogenous cyclic AMP is required for the fermentation of sucrose, trehalose, fructose, maltose, and mannose but not of glucose, as well as for the formation of normal flagella and specific somatic antigens. A striking characteristic of the mutants is their growth behavior at higher temperatures. They cannot grow on TCBS selective plates at 37 C or higher unless they are provided with a supply of exogenous cyclic AMP, although they are capable of producing colonies on the same medium, even without cyclic AMP, at temperatures lower than 30 C. Since the mutants are converted to spheroplasts, spindle forms, and spiral filaments in cyclic AMP-free media at 37 C, and this phenomenon is stopped by the addition of cyclic AMP or a combination of 20% sucrose and 0.2% magnesium chloride, it is assumed that cyclic AMP is essential for the synthesis of the cell wall of V. cholerae at higher temperatures.     

Mutants of Group D1Salmonella Carrying the Somatic Antigen of Group A Organisms: Isolation and Serological Characterization

O antigen mutants were obtained from Salmonella durban, a group D(1) organism, by treatment with N-methyl-N'-nitro-N-nitrosoguanidine. Serological studies demonstrated that the mutants lost the O-9 antigen factor of the parent organism but acquired the O-2 factor specific to group A Salmonella. Lipopolysaccharides of the mutant strains contained paratose which determines the specificity of O-2 factor. Tyvelose, present in the wild-type lipopolysaccharide, was not found in the mutants. H antigens and other biological characteristics of the mutant strains were the same as those of the wild-type organism. The present finding implies that group A Salmonella species might be derived from group D(1) organisms.     

Pituitary regulation of preovulatory estrogen secretion in the rat

The factors stimulating estrogen secretion in the preovulatory phase and an attempt to explain the mechanism of termination of estrogen secretion are discussed. Female Wistar rats, hypophysectomized at 1 p.m. in proestrus, were injected with rat pituitary extracts. Ovarian venous blood was collected and the estrogen activity of the plasma was measured. The estrogen secretion was minimized within 3 hours after hypophysectomy. The rat pituitary extract caused an 11-fold increase of estrogen concentration in the ovarian venous blood within 1 hour. Either LH or FSH alone was able to restore the estrogen secretion: LH took 1 hour to reach maximal response, FSH 2 hours. In the 1-hour test, the minimal effective dose for LH appeared to be less than .25 mcg per rat, for FSH, 2.5 mcg per rat. The total ability of the two preparations to produce estrogen appeared to be the same. 10 I.U. of prolactin slightly stimulated estrogen secretion, but 20 mU of ACTH was quite negative. These results demonstrate the pituitary gonadotropin dependency of estrogen secretion from the ovary having ripened follicles. It also showed that the ovary, after completion of ovulatory surge of LH, abolished its reactivity to the pituitary extract containing sufficient amount of substances in promoting estrogen secretion. Either LH or FSH was able to terminate estrogen secretion even at minute doses as small as 10 mcg. This shows that both FSH and LH provide a dual effect on ovarian estrogen secretion at the preovulatory stage, promotion and suppression. Promotion is an acute and direct action of hormones on steroidogenesis and suppression probably a delayed and indirect action of ovulation-inducing hormone, the release of which initiates the differentiation of estrogen-forming cells towards ovulation unfavorable to estrogen synthesis.     

Plant regeneration from isolated microspore cultures of Chinese cabbage (Brassica campestris spp. pekinensis)

Isolated microspores of Chinese cabbage (Brassica campestris ssp. pekinensis) were incubated in modified NN medium containing 10% sucrose in darkness at 33°C for one day followed by culture at 25°C. After 14 days of culture, microspores developed into embryos ranging from globular to cotyledonary stage. Plants were regenerated after transfer of embryos to medium containing 3% sucrose and no plant growth regulators.Abbreviations NN Nitsch and Nitsch - MS Murashige and Skoog - NAA naphthaleneacetic acid - BA 6-benzylaminopurine     

Fully differentiated Xenopus eye fragments regenerate to form pattern-duplicated visuo-tectal projections

In order to determine if differentiated Xenopus retina is capable of undergoing regeneration and duplicative pattern formation, we devised a new surgical technique for removal of the temporal two-thirds of the retina. In a series of progressively older larval eyes starting with late tailbud stage embryos (stage 38) and extending to limb-bud stage tadpoles (stage 48), nasal one-third-sized eye fragments successfully regenerated to form nearly normal sized eyes over 75% of the time. Histological preparations showed that early wound healing involved the formation of a neuroepithelium at the ventro-temporal region of the fragment. The pigmented retinal epithelium and associated retinal tissue appeared to be involved in this process. Animals from each stage were reared through metamorphosis and electrophysiologic techniques were employed to determine visuo-tectal projections. Seventy percent of stage 38 animals showed evidence of pattern-duplicated projections. Ninety percent of their responding tectal points showed duplicate innervation from two retinal regions. Older animals (stages 44 to 48) showed less duplication. Only 52% of their responding tectal points duplicated (P less than 0.001). Thus, fully differentiated Xenopus retina can undergo regeneration and duplicative pattern formation similar to that shown by embryonic retinal tissue.     

Tumor cytotoxicity of human monocyte membrane-bound interleukin-1α induced by synergistic actions of interferon-γ and synthetic acyltripeptide,FK-565

Summary Human blood monocytes were isolated by counter-flow centrifugal elutriation from healthy donors and these noncytotoxic monocytes were rendered tumoricidal to allogeneic melanoma (A375) cells by activation with a synthetic acyltripeptide (FK-565), as assessed by measuring release of [¹²⁵I]iododeoxyuridine in 72 h. When monocytes were treated with FK-565 for 16 h, and then fixed with paraformaldehyde, they showed cytotoxicity to A375 melanoma cells. The fixed-monocyte-mediated cytotoxicity to A375 cells was induced by the synergistic actions of FK-565 and recombinant interferon- (rIFN-), but not other cytokines [rIFN-A, rIFN-, tumor necrosis factor (TNF), interleukin (IL)-2, -3 and -6]. For synergistic activation of monocytes with induction of a membrane-associated antitumor monokine, the monocytes had to be incubated first with rIFN- and then with FK-565. FK-565 also acted synergistically with rIFN- to stimulate monocytes to produce membrane-associated IL-1 activity, which induced C3H/HeJ thymocyte blastogenesis in response to phytohemagglutinin P. The tumoricidal and thymocytestimulating activities of the fixed monocytes were almost completely inhibited by a specific anti-(IL-1) antiserum, but not by a specific anti-(IL-1) antiserum or monoclonal anti-TNF antibody. These results suggest that membrane-associated IL-1 of human blood monocytes can be induced by two activation signals (rIFN- then FK-565) at their suboptimal concentrations.Abbreviations IL interleukin - IFN interferon - TNF tumor necrosis factor