植物抗病基因工程进展(续)

植物抗病基因工程进展（续）洪剑明印莉萍邱泽生（首都师范大学生物系北京１０００３７）ＰＲＯＧＲＥＳＳＯＦＧＥＮＥＴＩＣＥＮＧＩＮＥＥＲＩＮＧＦＯＲＰＬＡＮＴＤＩＳＥＡＳＥＲＥＳＩＳＴＡＮＣＥＨＯＮＧＪｉａｎＭｉｎｇＹＩＮＬｉＰｉｎｇＱＩＵＺｅＳｈ...     

Population structure in the American oyster as inferred by nuclear gene genealogies

Multiple haplotypes from each of three nuclear loci were isolated and sequenced from geographic populations of the American oyster, Crassostrea virginica. In tests of alternative phylogeographic hypotheses for this species, nuclear gene genealogies constructed for these haplotypes were compared to one another, to a mitochondrial gene tree, and to patterns of allele frequency variation in nuclear restriction site polymorphisms (RFLPs) and allozymes. Oyster populations from the Atlantic versus the Gulf of Mexico are not reciprocally monophyletic in any of the nuclear gene trees, despite considerable genetic variation and despite large allele frequency differences previously reported in several other genetic assays. If these populations were separated vicariantly in the past, either insufficient time has elapsed for neutral lineage sorting to have achieved monophyly at most nuclear loci, or balancing selection may have inhibited lineage extinction, or secondary gene flow may have moved haplotypes between regions. These and other possibilities are examined in light of available genetic evidence, and it is concluded that no simple explanation can account for the great variety of population genetic patterns across loci displayed by American oysters. Regardless of the source of this heterogeneity, this study provides an empirical demonstration that different sequences of DNA within the same organismal pedigree can have quite different phylogeographic histories.      

Acute lesions of the ventromedial hypothalamus reduce sympathetic activation and thermogenic changes induced by PGE1

The aim of this experiment was to evaluate the effects of an intracerebroventricular (icv) injection of prostaglandin E1 (PGE₁) on the sympathetic activation and the thermogenic changes in rats with acute lesions of the ventromedial hypothalamus (VMH). Four groups of six Sprague-Dawley male rats were anesthetized with ethyl-urethane. The firing rate of the sympathetic nerves innervating the interscapular brown adipose tissue (IBAT) and the colonic and IBAT temperatures were monitored both before and after one of the following treatments: 1) VMH lesion plus icv injection of PGE₁ (500 ng); 2) VMH lesion plus icv injection of saline; 3) sham lesion plus icv injection of PGE₁; and 4) sham lesion plus icv injection of saline. PGE₁ induced an increase in the firing rate of IBAT nerves and the colonic and IBAT temperatures. These effects were reduced by VMH lesion. The findings indicate that acute lesions of the VMH reduce the effects of PGE₁ and seem to suggest a possible role played by the VMH in the control of the sympathetic activation and the thermogenic changes during PGE₁ hyperthermia.     

Reversible Inhibition of Lymphocyte-mediated Cytotoxicity by Cytochalasin B

ALLOGRAFT immunity is characterized by the appearance of sensitized lymphocytes which are specifically able in vitro to destroy target cells carrying the sensitizing alloantigens. These cytotoxic lymphocytes represent thymus-derived effector cells^1,2 and are quite distinct from alloantibody-producing cells, which are also formed during induction of allograft immunity³. Although contact between viable cytotoxic lymphocytes and target cells is necessary for destruction, the events which lead to target cell lysis are still unknown⁵.     

Leaf architecture characters of <i>Vachellia tortilis</i> (Forssk.) Galasso and Banfi along longitudinal gradient in Limpopo Province,South Africa

This paper looked at the leaf architecture characteristics of Vachellia tortilis to determine if either there is or not an effect of the tropic line on plants. Vachellia tortilis leaves were sampled along a national road (N1) in Limpopo province. Sampling points were set 10 km apart away from the Tropic of Capricon in opposite directions. Leaf morphology revealed that leaves of V. tortilis are bipinnately compound with alternate arrangement. The venation pattern of the pinnules was eucamptodromus and brochidodromous with imperfect reticulation. Areoles were imperfect and pentagonal or irregular in shape.     

Edible Lepidoptera in Mexico: Geographic distribution, ethnicity, economic and nutritional importance for rural people

In this paper, we reported the butterflies and moths that are consumed in Mexico. We identified 67 species of Lepidoptera that are eaten principally in their larval stage in 17 states of Mexico. These species belong to 16 families: Arctiidae, Bombycidae, Castniidae, Cossidae, Geometridae, Hepialidae, Hesperiidae, Lasiocampidae, Noctuidae, Nymphalidae, Papilionidae, Pieridae, Pyralidae, Saturniidae, Sesiidae, and Sphingidae. Saturniidae, Pieridae, Noctuidae and Nymphalidae were the more species consumed with 16, 11, 9, and 8 species, respectively. The genera with the largest numbers of species were: Phassus, Phoebis, Hylesia and Spodoptera, with three species. Their local distribution, corresponding to each state of Mexico, is also presented.     

Optimized labeling of bone marrow mesenchymal cells with superparamagnetic iron oxide nanoparticles and <Emphasis Type="Italic">in vivo</Emphasis> visualization by magnetic resonance imaging

Background  

Stem cell therapy has emerged as a promising addition to traditional treatments for a number of diseases. However, harnessing the therapeutic potential of stem cells requires an understanding of their fate in vivo. Non-invasive cell tracking can provide knowledge about mechanisms responsible for functional improvement of host tissue. Superparamagnetic iron oxide nanoparticles (SPIONs) have been used to label and visualize various cell types with magnetic resonance imaging (MRI). In this study we performed experiments designed to investigate the biological properties, including proliferation, viability and differentiation capacity of mesenchymal cells (MSCs) labeled with clinically approved SPIONs.