Numerical responses by populations of red fox and mountain hare during an outbreak of sarcoptic mange

Summary During a severe outbreak of sarcoptic mange (Sarcoptes scabiei vulpes) starting among red foxes (Vulpes vulpes) in Sweden in the 1970s, we studied: 1) the establishment and spread of the disease in northernmost Sweden (by inquiries), and 2) the 1970–84 bag records for foxes and mountain hares (Lepus timidus) (an alternative prey to the fox's main prey, voles). Since the first case of sarcoptic mange in 1975 the disease spread rapidly, with >50% of the hunting organizations having reported the disease in 1981 and >75% in 1983. Also the disease became more abundant within the areas affected. In areas with a low mange infection rate (index) the number of foxes killed in the 1980s did not deviate markedly from the average level in the 1970s. However, there was a slight tendency towards a decline in areas with a medium index and numbers declined markedly where the index was high. Hare harvests initially were low (after a tularemia epidemic) in the 1970s. In that decade harvests increased dramatically and stabilized, increased gradually or changed little, respectively, where mange infection rates were low, medium or high in the early 1980s. In areas with a low mange index hare harvests remained cyclical and at the same level in the 1980s as in most of the 1970s. However, in areas with a medium index harvests increased and seemed to begin to lose their cyclicity, and where the index was high the low and relatively stable hare harvests increased annually. A predator-prey hypothesis, assuming predators to synchronize alternative prey declines to those of the cyclic main prey, predicts that a predator reduction would cause a gradual disappearance of the cyclicity and increasing numbers among alternative prey. Our hare data are partially consistent with this prediction.     

Salinity and germination of annual Melilotus from the Guadalquivir delta (SW Spain)

The germination response to NaCl treatments has been studied in Melilotus seed populations collected from saline and non-saline soils in the Guadalquivir delta. The rank orders for salt tolerance and seed weight were the same in the threeMelilotus species living in this area:Melilotus messanensis>M. segetalis>M. indica. Within the species, differences in germination response to salinity were found inM. indica (6 populations) andM. segetalis (8 populations). The relationship between salt tolerance during germination and salinity of maternal habitat is discussed.     

云南呈贡梁王山现代花粉雨的研究

本文通过对云南呈贡梁王山5块表土分析,初步研究了主要植物花粉的百分含量与其植物覆盖率之间的数量关系,并用校正系数R值表示。按照R值的大小,分为两组:R>1属于超代表性,包括有松、桤木、马桑、蒿和部分蕨类植物;R<1属于低代表性,包括有油杉、栲和石栎、滇青冈、栎、铁仔。在分析松粉分布特征基础上,认为昆明地区西风急流对松粉的传播是主要因素。     

云南哀牢山南部鸟类的区系分析

哀牢山南延部分在云南省南部至东南部红河哈尼族彝族自治州(简称红河州)内,呈西北东南走向。南部为热带气候,北部为亚热带气候区。地势起伏虽不若滇西北三大峡谷之剧烈,但河口县与金平县内西隆山峰之高差却约达3,000米。这一南延部分区域内,植被类型复杂,花果繁茂,昆虫种类丰富。如此优越的自然条件,也导致了鸟类种类繁多昌盛的结果。     

The ecology of a beech forest on Mt. Sanpoiwadake,Hakusan National Park,Japan I. Braun-Blanquet,TWINSPAN and DCA analysis

The Lindero membranaceae-Fagetum crenatae association on Mt. Sanpoiwadake, Hakusan National Park, Japan, has been classified using traditional Braun-Blanquet methods. The association was floristically sub-divided into six communities, all of which had been included as four subassociations by Hukusima (1982). The resulting table was compared with an analogous community table derived using computer-based TWINSPAN analysis. This dual approach was shown to provide a fully objective classification by method, the subjective element in the Braun-Blanquet method thus being substantiated TWINSPAN. Subsequent ordination of the data using DCA then provided a further degree of objective evaluation allowing any misclassified stand or species to be re-examined, and at the same time displaying the detailed inter-relationships between all species or stands.     

Interferon affects the formation of adhesion plaques in human monocyte cultures

When monocytes isolated from human blood adhere to glass substratum, actin- and vinculin-containing punctate plaques rapidly appear at the ventral surface of the cells. We show here that highly purified human leukocyte interferon (IFN) can inhibit formation of these adhesion plaques in a dose-dependent manner. Complete inhibition was obtained when 300 IU/ml IFN were added into the cell-seeding medium. Plaques already formed in the absence of IFN were only partially affected by subsequent addition of IFN into the culture medium. Prevention by IFN of the formation of the adhesion plaques was associated with loosened attachment of the cells to the substratum. Effect of IFN on cellular morphology was complex. At higher doses, IFN added to the cultures within 24 h of seeding almost completely inhibited the differentiation of monocytes to macrophages and most of the cells remained rounded. At lower doses, however, an enhancement of the bipolar spreading was seen and the end result was a culture with predominantly elongated fibroblastoid cells. The latter cells, unlike the fibroblastoid cells in untreated monocyte-macrophage cultures, were completely devoid of the actin plaques, while the reorganization of vimentin-type intermediate filaments took place in a normal manner. These results further support the view that the actin- and vinculin-containing plaques have a role in mediating firm adherence of human monocytes to growth substratum.     

Vasoactive intestinal peptide effects on GH3 pituitary tumor cells: high affinity binding, affinity labeling, and adenylate cyclase stimulation. Comparison with peptide histidine isoleucine and growth hormone-releasing factor

The vasoactive intestinal polypeptide (VIP) receptor was characterized on the GH3 rat pituitary tumor cell line using competitive binding studies with peptides having sequence homology with VIP. Further studies investigated receptor coupling to the adenylate cyclase complex by measurement of cAMP levels. Finally, the molecular weight of the receptor was estimated by affinity labeling techniques. Studies using 125I-VIP and unlabeled competing peptides revealed a single class of high affinity binding sites with a dissociation constant (KD) of 17 +/- 2 nM (mean +/- S.E.M.) for VIP, 275 +/- 46 nM for peptide histidine isoleucine (PHI), and 1380 +/- 800 nM for human pancreatic growth hormone releasing factor (GHRF). VIP and PHI each stimulated intracellular cAMP accumulation in a dose-dependent manner; both peptides demonstrated synergism with forskolin. In contrast, GHRF neither stimulated accumulation of cAMP nor demonstrated synergism with forskolin. VIP plus PHI (1 microM each) caused no significant increase in cAMP over either VIP or PHI alone, implying that the two peptides act through the same receptor. Covalent crosslinking of 125I-VIP to its binding site using either disuccinimidyl suberate (DSS) or ethylene glycol bis(succinimidyl succinate) (EGS) was followed by SDS-PAGE and autoradiography. The result is consistent with an Mr 47 000 VIP-binding subunit comprising or being associated with the VIP receptor of GH3 pituitary tumor cells.     

Antigenic variation is associated with DNA rearrangements in a relapsing fever Borrelia

Borrelia hermsii, an agent of relapsing fever, undergoes antigenic variation in its host. Surface-exposed proteins with differing primary structures determine the serotype of each organism. Using amino acid sequence data from two of these variable proteins, we synthesized two mixed-sequence oligonucleotides and then used the oligonucleotides to probe mRNA and DNA of three isogenic serotypes of B. hermsii. In Northern blots the probes were specific for the mRNA of the homologous serotype. Southern blots revealed two classes of hybridizing fragments: those common to the three serotypes and those specific for a particular serotype. A serotype-specific DNA fragment, which had hybridized to both oligonucleotide probes, was cloned. Subsequent use of the cloned fragment as a probe provided further evidence that antigenic variation in B. hermsii is associated with DNA rearrangements and with occurrence of expression-linked copies of all, or part, of an antigen-specifying gene.     

The pathogenesis of trehalose dimycolate-induced interstitial pneumonitis: III. Evidence for a role for T lymphocytes

Trehalose dimycolate, a glycolipid component of the cell walls of mycobacteria, induces interstitial pneumonitis and alveolar hemorrhages in C57BL/6 and C57BL/10 mice. Homozygous nude (nu/nu) mice of these backgrounds are not susceptible to this form of pulmonary injury. However, after administration of T-lymphocyte-enriched spleen cell preparations from syngeneic donors, homozygous nude mice become susceptible to trehalose dimycolate. The observations suggest that production of pulmonary lesions by this mycobacterial component is dependent on T lymphocytes. While the mechanisms are still under study, we propose that trehalose dimycolate can function as an activator of T lymphocytes and that products of activated T cells are responsible for production of the pulmonary lesions.     

Cytostatic and cytolytic activities of macrophages regulation by prostaglandins

Murine peritoneal macrophages (M phi), activated in vivo or in vitro, remarkably inhibited the uptake of thymidine by a lens epithelial cell line, while resident M phi, or M phi induced by thioglycollate, exhibited much lower or no cytostatic capacity. The target cells were partially protected from the cytostatic activity by the anti-inflammatory agents indomethacin, aspirin, and dexamethasone, but not by lipoxygenase inhibitors. The protective activity of indomethacin and aspirin, but not of dexamethasone, was completely counteracted by prostaglandin E2 (PGE2). Yet, PGE2 alone has no effect on the uptake of [3H]thymidine by lens epithelial cells. PGE1 resembled PGE2 in its effect on this system, whereas PGA2, PGB2, or PGF2 alpha had no detectable activity. The counteracting effect of PGE2 was mimicked by dibutyryl cAMP or by cholera toxin, an agent which increases cAMP levels. These findings suggest that PGEs are not direct cytostatic agents, but rather, are essential mediators for the development of the cytostasis. Activated M phi did not lyse cells of the original lens epithelial cell line, but caused substantial cytolysis of cells of a subline derived from it. In contrast to its aforementioned effect on the cytostasis, PGE2 inhibited the cytolytic activity of M phi. Thus, this study provides a first demonstration in a single system of the opposite effects of PGEs on M phi activity on target cells, i.e., mediating the cytostasis and inhibiting the cytolysis.