Erratum

In the report "Similarity of synthetic peptide from human tumor to parathyroid hormone in vivo and in vitro," by N. Horiuchi et al. (11 Dec., p. 1566), the caption for figure 1 was inadvertently omitted. The figure is reprinted below with the caption. [See Fig. 1. in Source PDF].     

Glucose and weight control in mice with a designed ghrelin O-acyltransferase inhibitor

Ghrelin is a gastric peptide hormone that stimulates weight gain in vertebrates. The biological activities of ghrelin require octanoylation of the peptide on Ser(3), an unusual posttranslational modification that is catalyzed by the enzyme ghrelin O-acyltransferase (GOAT). Here, we describe the design, synthesis, and characterization of GO-CoA-Tat, a peptide-based bisubstrate analog that antagonizes GOAT. GO-CoA-Tat potently inhibits GOAT in vitro, in cultured cells, and in mice. Intraperitoneal administration of GO-CoA-Tat improves glucose tolerance and reduces weight gain in wild-type mice but not in ghrelin-deficient mice, supporting the concept that its beneficial metabolic effects are due specifically to GOAT inhibition. In addition to serving as a research tool for mapping ghrelin actions, GO-CoA-Tat may help pave the way for clinical targeting of GOAT in metabolic diseases.     

Ghrelin研究进展及在畜牧业中的应用前景

Ghrelin是生长激素促分泌物受体(GHS-R)的内源性配体,由28个氨基酸组成.机体的多种组织和器官都能分泌Ghrelin,但最主要的分泌器官是胃.Ghrelin主要功能是调节垂体的生长激素(GH)释放,参与能量代谢、增加摄食、影响心血管功能和调节其他激素的释放.对Ghrelin的化学结构、生理作用进行了简单综述,并展望了其在畜牧业中的应用前景.     

Comment on "Obestatin, a peptide encoded by the ghrelin gene, opposes ghrelin's effects on food intake"

Zhang et al. (Research Articles, 11 November 2005, p. 996) reported that obestatin, a peptide derived from the ghrelin precursor, activated the orphan G protein-coupled receptor GPR39. However, we found that I125-obestatin does not bind GPR39 and observed no effects of obestatin on GPR39-transfected cells in various functional assays (cyclic adenosine monophosphate production, calcium mobilization, and GPR39 internalization). Our results indicate that obestatin is not the cognate ligand for GPR39.     

植物声频控制技术对番茄生长性状、叶绿素及内源激素影响的研究

植物声频控制技术是利用作物与声波的协同关系,对作物发射一定波长和频率的声波,以促进作物生长及提高产量、质量的农业新技术.试验以番茄为试验材料,研究植物声频控制技术对番茄生长性状、叶绿素含量及内源激素生长素、赤霉素、玉米素核苷和脱落酸含量的影响.结果表明,植物声频控制技术能显著促进番茄的生长,可提高产量与叶片叶绿素的含量,还能刺激番茄内源激素生长素的分泌,并且刺激作用具有一定的时间积累效应.     

Molecular Cloning and Characteristics Analysis of ghrelin Gene in Asian Swamp Eel(Monopterus albus)

Ghrelin is an important signaling molecule linking reproductive and energy metabolism. In this study, ghrelin gene of Monopterus albus was cloned. Its structure and function were analysized preliminarily. By Rapid Amplification of cDNA Ends(RACE) technique, full-length cDNA and DNA sequences of ghrelin gene were obtained. The full-length ghrelin cDNA(GenBank accession no. JX122807) was 552 bp long, containing a 115 bp 5'-untranslated region, a 324 bp open reading frame and a 113 bp 3'-untranslated region. The full-length ghrelin DNA was 1 323 bp, consisting of three introns and four exons. The exon/intron junction sequences conformed to the GT/AG rule. Three introns were 594, 84 and 93 bp in length, respectively; four exons were229, 78, 112 and 133 bp in length, respectively. The results of amino acid sequence analysis showed that the deduced propreghrelin sequence of M. albus contained a signal peptide(SP) consisting of 22 amino acid residues, a mature peptide(MP)consisting of 19 amino acid residues and a C-terminal amino acid residue. Among them, the third amino acid of MP was serine(Ser~3) as the site for N-acylation and N-deacetylation reactions; the C-terminal amino acid residue sequence might contain a peptide hormone obestatin, which is a physiological antagonist of mature Ghrelin peptide. The homology and phylogenic relationships analyses of amino acid sequences suggested that propreghrelin of M. albus had high similarity to those of several Perciformes fishes; the propreghrelins of M. albus, Perciformes and Heterosomata fishes were clustered into a subgroup. The high conservatism of the gene structure and the amino acid sequences indicated that Ghrelin exerts important physiological functions and plays similar physiological mechanisms in vertebrates.     

Identification of a novel thyroid hormone receptor expressed in the mammalian central nervous system

A complementary DNA clone derived from rat brain messenger RNA has been isolated on the basis of homology to the human thyroid hormone receptor gene. Expression of this complementary DNA produces a high-affinity binding protein for thyroid hormones. Sequence analysis and the mapping of this gene to a distinct human genetic locus indicate the existence of multiple human thyroid hormone receptors. Messenger RNA from this gene is expressed in a tissue-specific fashion with highest levels in the central nervous system.     

Stimulation of gonadotropin release by a non-GnRH peptide sequence of the GnRH precursor

The human gonadotropin-releasing hormone (GnRH) precursor comprises the GnRH sequence followed by an extension of 59 amino acids. Basic amino acid residues in the carboxyl terminal extension may represent sites of processing to biologically active peptides. A synthetic peptide comprising the first 13 amino acids (H X Asp-Ala-Glu-Asn-Leu-Ile-Asp-Ser-Phe-Gln-Glu-Ile-Val X OH) of the 59-amino acid peptide was found to stimulate the release of gonadotropic hormones from human and baboon anterior pituitary cells in culture. The peptide did not affect thyrotropin or prolactin secretion. A GnRH antagonist did not inhibit gonadotropin stimulation by the peptide, and the peptide did not compete with GnRH for GnRH pituitary receptors, indicating that the action of the peptide is independent of the GnRH receptor. The GnRH precursor contains two distinct peptide sequences capable of stimulating gonadotropin release from human and baboon pituitary cells.     

Identification of a neuropeptide hormone that regulates sex pheromone production in female moths

A pheromone biosynthesis activating neuropeptide (PBAN) hormone that controls sex pheromone production in female moths was identified from the brain-subesophageal ganglion complexes of the adult corn earworm, Heliothis zea. PBAN has 33 amino acid residues and a molecular weight of 3900. Its amino acid sequence has no significant homology with any of the fully characterized peptide hormones. The synthetic peptide, at a dose of between 2 and 4 picomoles, induced production of a normal quantity of sex pheromone in ligated H. zea females. The peptide also induced pheromone production in six other species of moths, thus indicating that this or similar peptides may be responsible for the regulation of pheromone production in moths.     

Erratum

In the report "Antibodies to peptides detect new hepatitis B antigen: Serological correlation with hepatocellular carcinoma" by A. M. Moriarty, H. Alexander, G. B. Thornton, and R. A. Lerner (25 Jan., p. 429), the legend of table 1 should have begun, "Reactivity of human serum samples with peptide 99 and peptide 142," not "Reactivity of human liver samples...."     

植物激素与营养元素配合施用对苹果座果率的影响

1987～1988年用几种植物激素与营养元素配套喷施,对提高元帅苹果座果率的影响进行了试验。结果表明激素混合物比单一施用效果显著,处理A(GA30ppm+BA50ppm+EF150ppm),B(BA20ppm+EF150ppm)和C(EF200ppm十尿素O.4％+硼砂0.4％)能使元帅苹果在自然座果率8％的基础上达到翻番,满足了盛果树生产负载要求。试验还表明在花期逆境下激素混合物对提高座果的效应更大。为此,建议花期降温或受冻频繁的地区,激素混合物可作为生产常规措施应用。     

Amphibian pituitary growth hormone and prolactin: immunochemical relatedness to rat growth hormone

Growth hormone and prolactin were electrophoretically isolated from amphibian pituitaries and then were tested in a radioimmunoassay with labeled rat growth hormone and antiserum to the same hormone. This isolation and purification of the hormones increased the steepness of the slopes of competitive inhibition in this system when compared to those of crude extracts. Both hormones from most species tested showed high immunochemical cross-reactivity, indicating that amphibian growth hormone and prolactin are structurally related to rat growth hormone.     

Metrology and the state: science, revenue, and commerce

"Natural measures of quantity, such as fathoms, cubits, inches, taken from the proportion of the human body, were once in use with every nation," taught Adam Smith in his lecture "Money as the measure of value and medium of exchange," delivered in 1763. "But by a little observation," he continued, "they found that one man's arm was longer or shorter than another's, and that one was not to be compared with the other; and therefore wise men who attended to these things would endeavour to fix upon some more accurate measure, that equal quantities might be of equal values. Their method became absolutely necessary when people came to deal in many commodities, and in great quantities of them." Smith's comments and the rationale underpinning them became increasingly urgent toward the end of the eighteenth century.     

Apples in a spacecraft

Some consequences of Newtonian mechanics, previously overlooked, result in a new understanding of the behavior of small bodies in the solar system. Collisions between such bodies lead not to a scattering of these bodies over an increasing volume but instead to a contraction resulting in a "jet stream," with application to meteor streams and streams of asteroids. It is possible that comets are formed by bunching in such streams.     

Gonadotropin-releasing hormone binding sites in human breast carcinoma

Gonadotropin-releasing hormone analogs can cause regression of hormone-dependent breast carcinomas. These effects are thought to be mediated through the inhibition of gonadotropic and steroid hormones. These analogs may also act directly on the tumor because they are effective in treating breast cancer in some postmenopausal women. The presence of specific binding sites for gonadotropin-releasing hormone was demonstrated in human breast carcinomas by means of a novel approach of ligand immunoblotting. The results indicate a possible mechanism by which the peptide has direct effects on this tissue. These binding proteins were not detectable in non-neoplastic breast tissue.     

马铃薯外植体再生植株的研究

以马铃薯(Solanum tuberosum L.)6个栽培品种的叶圆片和幼茎切段作外植体,以 MS 为基本培养基,添加不同配比的激素制成4种诱导和分化培养基,研究这些外植体的再生植株分化率。结果表明,来自上述外植体的愈伤组织,苗的分化率平均分别为60.1%和88.7%.如果选择适当的基因型和激素配比,可使叶圆片和幼茎切段愈伤组织的成菡率分别高达162.3%和143.8%。     

Polypeptide with broad biological activity: isolation from small intestine

A polypeptide, which has potent and diverse biological action-including systemic vasodilation, hypotension, increased cardiac output, respiratory stimulation, and hyperglycemia-was isolated from the small intestine of the hog. The peptide has 28 amino acid residues and is chemically distinct from the kinins, "substance P," glucagon, and secretin.     

Thyroid hormone induction of an autocrine growth factor secreted by pituitary tumor cells

Thyroid hormones stimulate the rate of cell division by poorly understood mechanisms. The possibility that thyroid hormones increase cell growth by stimulating secretion of a growth factor was investigated. Thyroid hormones are nearly an absolute requirement for the division of GH4C1 rat pituitary tumor cells plated at low density. Conditioned media from cells grown with or without L-triiodothyronine (T3) were treated with an ion exchange resin to remove T3 and were tested for ability to stimulate the division of GH4C1 cells. Conditioned medium from T3-treated cells was as active as thyroid hormone at promoting GH4C1 cell growth but did not elicit other thyroid hormone responses, induction of growth hormone, and down-regulation of thyrotropin-releasing hormone receptors, as effectively as T3 did. A substance or substances associated with T3-induced growth stimulatory activity migrated at high molecular weight at neutral pH and was different from known growth-promoting hormones induced by T3. The results demonstrate that thyroid hormones stimulate the division of GH4C1 pituitary cells by stimulating the secretion of an autocrine growth factor.