In vitro transcription by isolated nuclei of Rhynchosciara americana salivary glands. Characteristics of incorporation and inhibition by alpha-amanitin

A method for the isolation of polytene nuclei from salivary glands cells of the Diptera Rhynchosciara americana is described. The stage-specific morphological pattern of the chromosome is maintained during the isolation. The isolated nuclei show two distinct RNA polymerase activities, namely I and II, characterized on the basis of ionic requirements and alpha-amanitin sensitivity. Studies of the product under the incubation conditions show that the system allows the synthesis of high-molecular weight RNA, beside a low molecular weight peak which may comprise pre-4S and 5S RNAs. Autoradiographic studies carried out in the presence or absence of the toxin alpha-amanitin showed that micronucleoli contain products of RNA polymerase type I activity (ribosomal RNA) and that the DNA puffs are engaged in alpha-amanitin sensitive RNA synthesis and thus are sites of polymerase type II activity.     

Recovery of memory after posthypnotic amnesia

Notes that documentation of the reversibility of posthypnotic amnesia has been hampered by the correlation of hypnotizability with the initial level of response to amnesia suggestions. 691 college students were placed in groups differing in hypnotic susceptibility that could be matched for initial amnesia recall, thereby eliminating the ceiling effect. At virtually every point along the distribution of initial amnesia response, hypnotizable Ss were significantly better able than insusceptible Ss to recapture the previously blocked memories after the amnesia suggestion was lifted. Conversely, those Ss who showed reversibility of amnesia were more responsive overall to hypnosis than those who did not. It is concluded that reversibility is of value in distinguishing between amnesia and pseudoamnesia and between partial amnesia and nonamnesia. Furthermore, reversibility helps define posthypnotic amnesia as a process involving the disruption of retrieval processes in memory. (15 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Congenital anomalies of the diaphragm. Personal experience with thirty-five consecutive cases

A personal experience of thirty-five consecutive patients with congenital anomalies of the diaphragm is reported. The anomalies included twenty-five Bochdalek hernias, seven diaphragmatic eventrations, and three esophageal hiatal hernias. Except for the patients with esophageal hiatal hernias, virtually all patients presented with respiratory embarrassment, twenty-seven of the thirty-five within 24 hours of birth. An especially high mortality is associated with this early onset of symptoms. The treatment was surgical with a thoracic approach used for right Bochdalek defects and eventrations, and an abdominal approach used for left Bochdalek hernias. The importance of proper preoperative and postoperative management in a well equipped neonatal intensive care unit is emphasized.     

Nondisjunction in aging female mice

Oocytes from CBA mice varying in age from 2 to 11 months were cultured to the metaphase II stage of meiosis and the chromosomes analyzed. The oocytes from three maternal age groups were compared with respect to the mean number of oocytes obtained per mouse, the frequency of maturation to metaphase II, and the frequency of numerical chromosomes abnormalities. Both the mean number of oocytes obtained per mouse and the frequency of maturation decreased markedly with maternal age. The frequency of chromosome abnormalities in the oocytes increased with maternal age from the young to the middle-aged mice but dropped off in the oldest maternal age group. No hyperploid (n + 1) oocytes were observed in the young or old group of mice, but 5.2% hyperploidy occurred in the middle-aged group. It is suggested that the lack of hyperploid oocytes in the old CBA females might be due to a threshold effect in which oocytes that are damaged by the number of univalents present at metaphase I become atretic and do not progress to metaphase II. The frequency of diploid (2n) oocytes was 1.7% and was not maternal-age dependent.     

Ruminal degradation of tannin‐treated legume meals

The inefficiency of protein utilisation by ruminants fed protein concentrates (based on legume meals) causes serious economic loss and environmental damage owing to their rapid hydrolysis and deamination in the rumen. Thus efforts aimed at slowing the ruminal fermentation of such feeds are needed, and recent studies have observed potentially positive effects of tannins on ruminant nutrition under certain circumstances. Tannins are a complex group of naturally occurring plant polyphenols characterised by their ability to bind with proteins. This property of tannins is considered responsible for the decreased ruminal digestibility of forages both in vivo and in vitro. Under that perspective, commercial tannic acid was added at three proportions (10, 25 and 50 g kg^?1 on a dry matter basis) to four different legume meals (horse bean, kidney bean, soybean and pea), and the effect on in situ dry matter and crude protein ruminal disappearance was assessed. The results confirmed the dose‐dependent (although not persistent after 48 h) slowing of in situ digestibility, this effect being significant at the highest tannin treatment when compared with untreated samples. Scanning electron microscopy revealed that soybean seed endosperm cell walls were protected from digestion by the ruminal microbiota, while the digestion of starch granules was relatively unaffected by tannic acid. Electrophoresis of the protein fractions confirmed the lower digestibility of tannin‐treated seeds as well as the relative lack of alteration of the electrophoretic profile of individual proteins. Implications for the digestion of concentrates in ruminants are discussed. Copyright © 2004 Society of Chemical Industry     

Bioassay for determining 2,3,7,8-tetrachlorodibenzo-p-dioxin equivalents (TEs) in human hepatoma Hepg2 cells

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD), 2,3,7,8-tetrachlorodibenzofuran (TCDF), and benz[a]anthracene (BA) highly induce cytochrome P4501A1, determined by aryl hydrocarbon hydroxylase (AHH) activity, in human hepatoma HepG2 cells within 24 h. AHH activity induced by TCDD and TCDF persists for at least 48 h. In contrast, AHH activity induced by BA rapidly declines, although the amounts applied are 4-5 orders of magnitude higher than those of TCDD or TCDF. AHH induction in HepG2 cells differs from that in rat hepatoma cells H4IIEC3/T in two aspects: (1) HepG2 cells are 20 times less sensitive to the test compounds than H4IIEC3/T cells. (2) TCDF-induced AHH activity does not persist in the rat cells. The results suggest that human HepG2 cells, because of their low sensitivity, are inferior to rat H4IIEC3/T cells for determining TCDD equivalents in environmental samples. They may be useful for investigating species dependent differences in the toxicokinetics of individual polyhalogenated aromatic hydrocarbon congeners.     

Purification, characterization, and spasmogenic activity of neurotensin from the toad Bufo marinus

Neurotensin (NT) was isolated from an extract of the intestine of the cane toad, Bufo marinus and its primary structure established as: pGlu-Ala-Ile-Val-Ser-Lys-Ala-Arg-Arg-Pro-Tyr-Ile-Leu. This amino acid sequence shows five substitutions (Leu2 --> Ala, Tyr3 --> Ile, Glu4 --> Val, Asn5 --> Ser, and Pro7 --> Ala) compared with bovine NT. Synthetic Bufo NT (pD2 = 8.05 +/- 0.28) was equipotent and equally effective as bovine NT (pD2 = 8.24 +/- 0.38) in producing spasmogenic contraction of isolated segments of toad small intestine. However, the maximum response produced by Bufo NT was only 35 +/- 2% of that produced by substance P. The potencies, but not the maximum responses, to Bufo and bovine NT were significantly (p < 0.05) attenuated by pre-treatment with atropine but neither parameter was significantly diminished by tetrodotoxin and indomethacin. The data suggest that the action of NT involves interaction with receptors on toad intestinal smooth muscle that recognize the C-terminal region of NT (residues 8-13) that has been fully conserved during evolution of tetrapods. Contractile activity is mediated, at least in part, by release of acetylcholine.     

Enhancement of the Antitumour Activity for the Synthesised Dodecylcysteine Surfactant using Gold Nanoparticles

In this paper, the surfactant dodecylcysteine hydrochloride was synthesised. The surface parameters of the synthesised surfactant were studied using a surface tension technique. The surface parameters show a good surface activity of the prepared surfactant in aqueous solution. The self-assembling behaviour of the synthesised surfactant comparing with that of cysteine compound on the prepared gold nanoparticles was confirmed using transmission electron microscope (TEM) measurements. The effect of self-assembling of this surfactant on the size of gold nanoparticles was studied using TEM images. The antitumour activity of the prepared surfactant without and with the gold nanoparticles was investigated. The results show that the antitumour activity of the prepared surfactant was enhanced with the presences of the gold nanoparticles.