Toward a molecular paleontology of primate genomes

KpnI restriction of anthropoid primate DNAs, from a New World monkey to man, releases a series of segments that are remarkable among all of the alphoid DNAs in the constancy of their relative amounts in the various primate genomes, in their long-range organization, and in their internal sequence structure. These segments are labeled the KpnI A, B, C and D segments. Cross-hybridization analysis by Southern filter-transfer hybridization indicates that the KpnI segments represent separate and distinct families of alphoid DNAs. These families are termed the KpnI A, B, C and D families of alphoid sequences, of which only the KpnI A and B families were studied in detail here. - Evidence is presented suggesting that the KpnI segments do not exist as long, tandemly repeated sequences in the primate genome: rather, they may occur interspersed among other, perhaps nonalphoid sequences. From the stained gel patterns and from Southern filter-transfer hybridization experiments, the KpnI families appear to be absent from the genomes of the two prosimians studied - the galago and the black lemur. The KpnI A and B families are found among all of the anthropoid primates, including the New World capuchin monkey. The KpnI C family was detected in the genomes of the Old World anthropoid primates whereas the KpnI D family was detected only among the great apes and man. - The results are in accord with the observation (Musich et al., 1980) that with the continued evolutionary development of the primate Order, there has been a parallel trend toward an increased number and variety of alphoid DNA sequences. The properties of the KpnI families suggest that these sequences, unique among the alphoid DNAs, have been conservatively maintained throughout primate phylogeny and that they are among the most ancient of all primate DNAs.     

Highly repetitive component α and related alphoid DNAs in man and monkeys

The genomes of Old-World, New-World, and prosimian primates contain members of a large class of highly repetitive DNAs that are related to one another and to component DNA of the African green monkey by their sequence homologies and restriction site periodicities. The members, of this class of highly repetitive DNAs are termed the alphoid DNAs, after the prototypical member, component of the African green monkey which was the first such DNA to be identified (Maio, 1971) and sequenced (Rosenberg et al., 1978). The alphoid DNAs appear to be uniquely primate sequences. — From the restriction enzyme cleavage patterns and Southern blot hybridizations under different stringency conditions, the alphoid DNAs comprise multiple sequence families exhibiting varying degrees of homology to component DNA. They also share common elements in their restriction site periodicities (172 · n base-pairs), in the long-range organization of their repeating units, and in their banding behavior in CsCl and Cs₂SO₄ buoyant density gradients, in which they band within the bulk DNA as cryptic repetitive components. — In the three species from the Family Cercopithecidae examined, the alphoid DNAs represent the most abundant, tandemly repetitive sequence components, comprising about 24% of the African green monkey genome and 8 to 10% of the Rhesus monkey and baboon genomes. In restriction digests, the bulk of the alphoid DNAs among the Cercopithecidae appeared quantitatively reduced to a simple series of arithmetic segments based on a 172 base-pair (bp) repeat. In contrast with these simple restriction patterns, complex patterns were observed when human alphoid DNAs were cleaved with restriction enzymes. Detailed analysis revealed that the human genome contains multiple alphoid sequence families which differ from one another both in their repeat sequence organization and in their degree of homology to the African green monkey component DNA. — The finding of alphoid sequences in other Old-World primate families, in a New-World monkey, and in a prosimian primate attests to the antiquity of these sequences in primate evolution and to the sequence conservatism of a large class of mammalian highly repetitive DNA. In addition, the relative conservatism exhibited by these sequences may distinguish the alphoid DNAs from more recently evolved highly repetitive components and satellite DNAs which have a more restricted taxonomical distribution.     

铅锌镉联合染毒及营养干预对大鼠血液系统的影响研究

目的：了解铅锌镉联合染毒对大鼠血液系统的影响及营养干预对其损伤的修复作用。方法：选择SPF级初断乳Wistar大鼠72只,随机分为对照组、染毒组和干预组,分别采用生理盐水、铅锌镉联合染毒液及染毒后以营养干预液灌胃28天和56天之后,检测其血液系统中五元素和血细胞的指标。结果：染毒组较对照组大鼠血铜、血锌含量高,血钙含量低于对照组,差异均有统计学意义（P〈0．05）;染毒组血铜含量高于干预组,血钙含量低于干预组,差异均有统计学意义（P〈0．05）;干预组红细胞（RBC）计数、血红蛋白（Hb）、血细胞比容（HCT）均高于染毒组,差异均有统计学意义（P〈0．05）;对照组白细胞（WBC）计数高于染毒组、干预组,差异均有统计学意义（P〈0．05）。结论：铅镉对大鼠血铜、血钙、血锌水平有影响;综合营养干预对重金属元素造成的血液系统损伤有明显的拮抗作用,对血液系统有一定的保护及修复作用。     

Amblyomma sculptum: genetic diversity and rickettsias in the Brazilian Cerrado biome

Amblyomma sculptum (Ixodida: Ixodidae) Berlese, 1888 is the most important tick vector in Brazil, transmitting the bioagent of the most severe form of spotted fever (SF) in part of the Cerrado (in the states of Minas Gerais and São Paulo). In another part of the Cerrado (Central‐West region of Brazil), a milder form of SF has been recorded. However, neither the rickettsia nor the vector involved have been characterized. The aim of the current study was to analyse genetic variation and the presence of rickettsia in A. sculptum in Cerrado, from silent areas and with the milder form of SF. Samples were subjected to DNA extraction, amplification and sequencing of 12S rDNA, cytochrome oxidase subunit II and D‐loop mitochondrial genes (for tick population analyses), and gltA, htrA, ompA and gene D (sca4) genes for rickettsia researches. Exclusive haplotypes with low frequencies, high haplotype diversity and low nucleotide diversity, star‐shaped networks and significant results in neutrality tests indicate A. sculptum population expansions in some areas. Rickettsia amblyommatis, Candidatus Rickettsia andeanae and Rickettsia felis were detected. The A. sculptum diversity is not geographically, or biome delimited, pointing to a different potential in vector capacity, possibly associated with differing tick genetic profiles.     

Herpetomonas megaseliae, Crithidia fasciculata, and Leptomonas collosoma (Kinetoplastida, Trypanosomatidae) in Feces of Lizards Fed Culture Forms of the Flagellates

ABSTRACT. Herpetomonas megaseliae, Crithidia fasciculata , and Leptomonas collosoma from culture survived gut passage in Anolis carolinensis following their ingestion by this lizard. Maximum persistence of H. megaseliae in lizards, as detected by fecal culture, was seven days. No invasion of tissues by H. megaseliae could be detected by means of sectioned material, stained impression slides, or cultures inoculated with material from organs. Crithidia fasciculata was evident in cloacal fluid for up to three days in wet mount preparations. Leptomonas collosoma was observed in feces 24 h after the organisms were fed to lizards. Both C. fasciculata and L. collosoma were cultured from feces of lizards fed the parasites 24 h earlier. Herpetomonas megaseliae was differentiated in lizard feces, with greater than 40% of the forms observed being paramastigotes or opisthomastigotes. Truncate, semispherical forms resembling choanomastigotes were seen, but the kinetoplast was posterior to the nucleus in some of these. Many forms showed extensive coiling of the axoneme within the body of the flagellate. Choanomastigotes and spheromastigotes of C. fasciculata and promastigotes, sphero-mastigotes and amastigotes of L. collosoma were also observed in the feces.