Vacuolar reticulum in oomycete hyphal tips: An additional component of the Ca2+Regulatory system?

Cultures of Achlya sp., Phytophthora cinnamomi, Saprolegnia diclina, S. ferax, and S. parasitica, treated with 6-carboxyfluorescein diacetate solution, accumulate 6-carboxyfluorescein in a reticulate system of fine tubules. The network shows longitudinal polarity within the hyphae, tubules being finest toward the hyphal tips. In more mature subapical regions the network is connected with large vacuoles that also accumulate 6-carboxyfluorescein. A morphologically similar system has also been identified in freeze-substituted hyphae of S. ferax. The network is considered to be vacuolar, but differs from the tubular vacuole system of true fungi in that tubules are less motile, more frequently branched, and do not alternate with clusters of spherical vacuoles. The appearance of the network resembles patterns of calcium-sensitive dye staining and it is suggested that the vacuolar reticulum in the tip region of oomycete hyphae may act as a Ca2+ sink. The tubular reticulum in oomycetes is very fragile and can be shown with 6-carboxyfluorescein in only those hyphal tips with a motility and organelle distribution characteristic of growing hyphae with normal morphology. Diverse abnormal hyphae show a range of other fluorochrome localizations. These include large irregular compartments filled with fluorochrome, and fluorescent cytoplasm with organelles and vacuoles standing out in negative contrast. These localizations in abnormal hyphae are correlated with other structural changes indicative of damage. Special care is required in experiments with oomycetes to avoid such artefacts of localization. Copyright 1997 Academic Press. Copyright 1997 Academic Press     

A reassessment of decreased amino acid accumulation by ehrlich ascites tumor cells in the presence of metabolic inhibitors

This study was undertaken to examine the mechanism by which metabolic inhibition reduces amino acid active transport in ehrlich ascites tumor cells. At 37 degrees C the metabolic inhibitor combination 0.1 mM 2,4-dinitrophenol (DNP) + 10 mM 2- deoxy-D-glucose (DOG) reduced the cell ATP concentration to 0.10- 0.15 mM in less than 5 min. This inhibition was associated with a 20.6 percent +/- 6.4 percent (SD) decrease in the initial influx of α-aminoisobutyric acid (AIB), and a two- to fourfold increase in the unidirectional efflux. These effects could be dissociated from changes in cell Na(+) or K(+) concentrations. Cells incubated to the steady state in 1.0-1.5 mM AIB showed an increased steady-state flux in the presence of DNP + DOG. Steady- state fluxes were consistent with trans-inhibition of AIB influx and trans-stimulation of efflux in control cells, but trans- stimulation of both fluxes in inhibited cells. In spite of the reduction of the cell ATP concentration to less than 0.15 mM and greatly reduced transmembrane concentration gradients of Na(+) and K(+), cells incubated to the steady state in the presence of the inhibitors still established an AIB distribution ration 13.8 +/- 2.6. The results are interpreted to indicate that a component of the reduction of AIB transport produced by metabolic inhibition is attributable to other actions in addition to the reduction of cation concentration gradients. Reduction of cell ATP alone is not responsible for the effects of metabolic inhibition, and both the transmembrane voltage and direct coupling to substrate oxidation via plasma-membrane-bound enzymes must be considered as possible energy sources for amino acid active transport.     

用5-Fu治疗MT/p210bcr-abl转基因小鼠的研究

以５－氟脲嘧啶（５－ｆｌｕｏｒｏｕｒａｃｉｌ,５－Ｆｕ）腹腔注射治疗了１２只携有金属硫蛋白（Ｍｅｔａｌｏｔｈｉｏｎｅｉｎ,ＭＴ）启动子和增强子序列、ｂｃｒ－ａｂｌｃＤＮＡ（ｐ２１０）序列及ＳＶ４０剪切和Ｐｏｌｙ（Ａ）信号序列的转基因慢粒白血病（ｃｈｒｏｎｉｃｍｙｅｌｏｉｄｌｅｕｋｅｍｉ－ａ,ＣＭＬ）ＭＴ／ｐ２１０ｂｃｒ－ａｂｌ小鼠,于治疗的第５ｄ及第１０ｄ从不同脏器提取总ＲＮＡ、ＤＮＡ及蛋白质,分别进行ＰＣＲ分析、ＲＴ－ＰＣＲ检测被转移基因的表达水平及免疫沉淀法分析ｐ２１０ｂｃｒ－ａｂｌ转基因产物的激酶活性．结果表明,被转移基因在脾脏和骨髓中表达水平较高,胸腺和肾脏中呈低水平表达．５－Ｆｕ活体治疗１０ｄ后,被转移基因的表达水平及其表达产物的激酶活性均被明显抑制     

Observations on behaviour and foraging of the Ibisbill Ibidorhyncha struthersii in Nepal

In March and April 1984, I studied the territorial, courtship and foraging behaviour of Ibisbills Ibidorhyncha struthersii , mainly on Langtang Khola in Nepal. On their river-bed breeding grounds, Ibisbills were territorial, rival birds meeting on shingle banks and performing prolonged circling displays. Aquatic invertebrates, especially stoneflies, mayflies and caddisflies, were the main prey, but fish and riparian invertebrates were taken also. When the water temperature was below 5^oC, invertebrates were inactive and hidden beneath submerged stones, where the birds probed for them. When the water temperature was above 5^oC, many invertebrates drifted in the water and Ibisbills switched to pecking at them from preferred feeding stations. Riparian foraging involved probing beneath stones on shingle banks and probing into soil. Foraging responses to changes in prey behaviour were similar to those of the Black Stilt Himantopus novaezealandiae on New Zealand river-beds.     

Phylogeny and historical biogeography of the subtribe Aporiina (Lepidoptera: Pieridae): implications for the origin of Australian butterflies

The Australian fauna is composed of several major biogeographical elements reflecting different spatial and temporal histories. Two groups of particular interest are the Gondwanan Element, reflecting an ancient origin in Gondwana or southern Gondwana (southern vicariance hypothesis), and the Asian Element, reflecting a more recent origin in Asia, Eurasia or Laurasia (northern dispersal hypothesis). Theories regarding the origin and evolution of butterflies (Hesperioidea, Papilionoidea) in Australia are controversial, with no clear consensus. Here, we investigate the phylogenetic and historical biogeographical relationships of the subtribe Aporiina, a widespread taxon with disjunct distributions in each of the major zoogeographical regions. Attention is paid to origins of the subtribe in the Australian Region for which several conflicting hypotheses have been proposed for the Old World genus Delias Hübner. Our phylogenetic reconstruction was based on analysis of fragments of two nuclear genes (elongation factor‐1α, wingless) and one mitochondrial gene (cytochrome oxidase subunit I) for 30 taxa. Phylogenetic analyses based on maximum parsimony, maximum likelihood and Bayesian inference of the combined data set (2729 bp; 917 parsimony informative characters) recovered six major lineages within the monophyletic Aporiina, with the following topology: (Cepora + Prioneris + (Mylothris + (Aporia + Delias group + Catasticta group))). Given a probable age of origin of the stem‐group near the Cretaceous/Tertiary boundary (69–54 Mya), followed by diversification of the crown‐group in the early to mid Tertiary (57–45 Mya), we show that an origin of the Aporiina in either southern Gondwana or Laurasia is equally parsimonious, and that dispersal has played a major role in shaping the underlying phylogenetic pattern. We tentatively conclude that an origin in southern Gondwanan is more likely; however, neither hypothesis satisfactorily explains the present‐day distribution, and additional lower‐level phylogenies are needed to determine the directionality of dispersal events of several taxa and to reject one hypothesis over the other. Dispersal is inferred to have occurred primarily during cooler periods when land bridges or stepping‐stones were available between many of the zoogeographical regions. © 2007 The Linnean Society of London, Biological Journal of the Linnean Society, 2007, 90 , 413–440.