New evidence for enhanced cosmogenic isotope production rate in the atmosphere ≈37 kaBP from the Guliya ice core

A³⁶Cl peak was found in the predicted section of Guliya ice core, from the Qinghai-Tibetan Plateau, at about 37 kaBP. This cannot be interpreted by means of changes in the accumulation rate, but by the enhanced cosmogenic isotope production rate in the atmosphere. Compared with the records of¹⁰Be and³⁶Cl in the other regions, the peaks of the cosmogenic isotopes are global and can be considered as time marks. An intriguing fact is that the peaks coincided with cold periods.     

Isolation and quantification of soluble Alzheimer's beta-peptide from biological fluids.

Cerebral deposition of the beta-amyloid peptide (A beta) is an invariant feature of Alzheimer's disease. Since the original isolation and characterization of A beta (ref. 1) and the subsequent cloning of its precursor protein, no direct evidence for the actual production of discrete A beta has been reported. Here we investigate whether A beta is present in human biological fluids using antibodies specific for an epitope within A beta that spans the site of normal constitutive cleavage. These antibodies were used to construct a sandwich-type enzyme-linked immunosorbent assay that detects A beta in cerebrospinal fluid, plasma and conditioned medium of human mixed-brain cells grown in vitro (see also ref. 14). By affinity chromatography, we have purified and sequenced A beta and a novel A beta fragment from human cerebrospinal fluid and conditioned medium of human mixed-brain cell cultures. These findings demonstrate that A beta is produced and released both in vivo and in vitro. These observations offer new opportunities for developing diagnostic tests for Alzheimer's disease and therapeutic strategies aimed at reducing the cerebral deposition of A beta.     

呼肠孤病毒科斐济病毒属一新种:南方水稻黑条矮缩病毒

近年在广东省和海南省部分地区新发生一种水稻病毒病, 其症状表现为植株矮缩、叶色深绿、叶背及茎秆出现条状乳白色或深褐色小突起、高位分蘖及茎节部倒生气生须根. 病株韧皮部细胞内可观察到具斐济病毒特征性晶格状排列直径为70~75 nm的球状病毒粒体以及病毒基质和管状结构. 从发病田块及其附近的玉米(Zea mays)、稗草(Echinochloa crusgalli)、水莎草(Juncellus serotinus)和白草(Pennisetum flaccidum)植株体内检测到病原病毒的存在. 田间调查及室内传毒实验表明, 白背飞虱(Sogatella furcifera)是该病毒的主要传毒介体. 该病毒的基因组由10条dsRNA组成, 其电泳图谱与水稻黑条矮缩病毒(Rice black-streaked dwarf virus)基本相同. 采用接头单引物扩增法获得了该病毒基因组两个片段(S9和S10)全长核苷酸序列, 两者在核苷酸组成、末端序列及基因排列上均具斐济病毒特征, 但与斐济病毒属已知种核苷酸同一率小于75% (S9)和80% (S10), 基于核苷酸及其推导编码产物氨基酸序列构建的系统进化树表明, 该病毒在斐济病毒属中处于相对独立的进化位置. 结果表明, 该病毒应为呼肠孤病毒科(Reoviridae)斐济病毒属(Fijivirus)第2组的一个新种, 建议将其命名为南方水稻黑条矮缩病毒(Southern rice black-streaked dwarf virus).     

A comparison of the pharmacological activity ofgD 9-Tetrahydrocannabinol and its monohydroxylated metabolites in man

Resumen Se hizo un estudio comparativo de la capacidad del ⁹-tetrahidro-cannabinol y de sus metabolitos monohidroxilados en producir effectos similares a los de la marihuana cuando son inyectados intravenosamente a humanos. Se encontro que la hidroxilacion en la posición 11 no cambio la potencia, en la posición 8 la redujo, y en la posición 8 la abolio por completo.

---

---

These studies were conducted under Contract No. HSM-42-71-95 between the Center for Studies of Narcotic and Drug Abuse of the Division of Narcotic Addition and Drug Abuse, NIMH, and the Research Triangle Institute. In addition, this investigation was supported by Public Health service Research Grant No. RR-46 from the General Clinical Research Centers Branch of the Division of Research Resources. We thank Drs.Monique Braude and st.Szara, Center for Studies of Narcotic and Drug Abuse, NIMH, for their interest and encouragement of this program. We also thankCarolyn Bishop andDaynise Skeen for their technical assistance.     

Uterine fluid proteins bind sperm cholesterol during capacitation in the rabbit

Summary Cholesterol from rabbit sperm cells was bound by uterine fluid proteins following intrauterine insemination into ovulating does. Serum albumin has been identified as a uterine sterol acceptor. Progesterone administration suppressed binding and elevated the concentration of cholesterol, phospholipid, and protein. Uterine fluid cholesterol affinity, therefore, correlated with sperm capacitation activity in utero.I thank N. V. Davis for her assistance during this study. Financial support was received from N.I.H. grant HD 16238.     

Mammalian and bacterial sugar transport proteins are homologous

The uptake of a sugar across the boundary membrane is a primary event in the nutrition of most cells, but the hydrophobic nature of the transport proteins involved makes them difficult to characterize. Their amino-acid sequences can, however, be determined by cloning and sequencing the corresponding gene (or complementary DNA). We have determined the sequences of the arabinose-H+ and xylose-H+ membrane transport proteins of Escherichia coli. They are homologous with each other and, unexpectedly, with the glucose transporters of human hepatoma and rat brain cells. All four proteins share similarities with the E. coli citrate transporter. Comparisons of their sequences and hydropathic profiles yield insights into their structure, functionally important residues and possible evolutionary relationships. There is little apparent homology with the lactose-H+ (LacY) or melibiose-Na+ (MelB) transport proteins of E. coli.