Pliocene and Pleistocene events shaping the genetic diversity within the central corridor of the Brazilian Atlantic Forest

Dinoponera lucida (Formicidae; Ponerinae) is an extinction‐threatened species of ant which is endemic in the central corridor of the Atlantic Forest. We used mitochondrial sequences of the Cox1, Cox2 and Cytb genes in order to infer some aspects of the evolutionary history and phylogeography of this ant. High genetic divergence and population structure were observed for the whole species. The current pattern of D. lucida diversity seems to be shaped during different geological times: middle Pliocene, early Pleistocene and mainly late Pleistocene, when the reduction of populations generated a structure pattern of the genetic variation of this species. Our data show that this structure results from the maintenance of populations of D. lucida within very small putative refuges to the south of the central Bahia refugium. We thus argue that, for some Atlantic forest endemic species, especially those resistant to very small fragments of forest, such as D. lucida, the small putative refuges were as important as, or even more important than, larger and stable refuges for the creation and maintenance of diversity, adding another piece to the puzzle of the mechanisms underlying local endemism. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 101 , 949–960.     

Post-glacial redistribution and shifts in productivity of giant kelp forests

Quaternary glacial–interglacial cycles create lasting biogeographic, demographic and genetic effects on ecosystems, yet the ecological effects of ice ages on benthic marine communities are unknown. We analysed long-term datasets to develop a niche-based model of southern Californian giant kelp (Macrocystis pyrifera) forest distribution as a function of oceanography and geomorphology, and synthesized palaeo-oceanographic records to show that late Quaternary climate change probably drove high millennial variability in the distribution and productivity of this foundation species. Our predictions suggest that kelp forest biomass increased up to threefold from the glacial maximum to the mid-Holocene, then rapidly declined by 40–70 per cent to present levels. The peak in kelp forest productivity would have coincided with the earliest coastal archaeological sites in the New World. Similar late Quaternary changes in kelp forest distribution and productivity probably occurred in coastal upwelling systems along active continental margins worldwide, which would have resulted in complex shifts in the relative productivity of terrestrial and marine components of coastal ecosystems.     

Female giant panda (Ailuropoda melanoleuca) chirps advertise the caller's fertile phase

Although female mammal vocal behaviour is known to advertise fertility, to date, no non-human mammal study has shown that the acoustic structure of female calls varies significantly around their fertile period. Here, we used a combination of hormone measurements and acoustic analyses to determine whether female giant panda chirps have the potential to signal the caller''s precise oestrous stage (fertile versus pre-fertile). We then used playback experiments to examine the response of male giant pandas to female chirps produced during fertile versus pre-fertile phases of the caller''s reproductive cycle. Our results show that the acoustic structure of female giant panda chirps differs between fertile and pre-fertile callers and that male giant pandas can perceive differences in female chirps that allow them to determine the exact timing of the female''s fertile phase. These findings indicate that male giant pandas could use vocal cues to preferentially associate and copulate with females at the optimum time for insemination and reveal the likely importance of female vocal signals for coordinating reproductive efforts in this critically endangered species.     

Drosophila rolling blackout displays lipase domain-dependent and -independent endocytic functions downstream of dynamin

Drosophila temperature-sensitive rolling blackout (rbo(ts) ) mutants display a total block of endocytosis in non-neuronal cells and a weaker, partial defect at neuronal synapses. RBO is an integral plasma membrane protein and is predicted to be a serine esterase. To determine if lipase activity is required for RBO function, we mutated the catalytic serine 358 to alanine in the G-X-S-X-G active site, and assayed genomic rescue of rbo mutant non-neuronal and neuronal phenotypes. The rbo(S358A) mutant is unable to rescue rbo null 100% embryonic lethality, indicating that the lipase domain is critical for RBO essential function. Likewise, the rbo(S358A) mutant cannot provide any rescue of endocytic blockade in rbo(ts) Garland cells, showing that the lipase domain is indispensable for non-neuronal endocytosis. In contrast, rbo(ts) conditional paralysis, synaptic transmission block and synapse endocytic defects are all fully rescued by the rbo(S358A) mutant, showing that the RBO lipase domain is dispensable in neuronal contexts. We identified a synthetic lethal interaction between rbo(ts) and the well-characterized dynamin GTPase conditional shibire (shi(ts1)) mutant. In both non-neuronal cells and neuronal synapses, shi(ts1); rbo(ts) phenocopies shi(ts1) endocytic defects, indicating that dynamin and RBO act in the same pathway, with dynamin functioning upstream of RBO. We conclude that RBO possesses both lipase domain-dependent and scaffolding functions with differential requirements in non-neuronal versus neuronal endocytosis mechanisms downstream of dynamin GTPase activity.     

Sequencing,annotation and comparative analysis of nine BACs of the giant panda(Ailuropoda melanoleuca)

A 10-fold BAC library for the giant panda was constructed and nine BACs were selected to generate finish sequences.These BACs could be used as a validation resource for the de novo assembly accuracy of the whole genome shotgun sequencing reads of the giant panda newly generated by Illumina GA sequencing technology.Complete Sanger sequencing,assembly,annotation and comparative analysis were carried out on the selected BACs of a joint length 878 kb.Homologue search and de novo prediction methods were used to ...     

A marked enhancement in phytase production by a thermophilic mould Sporotrichum thermophile using statistical designs in a cost-effective cane molasses medium

AIMS: Statistical optimization of phytase production by a thermophilic mould Sporotrichum thermophile in a cost-effective cane molasses medium. METHODS AND RESULTS: Sporotrichum thermophile secreted phytase in cane molasses medium at 45 degrees C and 250 rev min(-1) after 5 days. The important factors identified by Plackett-Burman design (magnesium sulfate, Tween 80, ammonium sulfate and incubation period) were further optimized by response surface methodology (RSM). An overall 107% improvement in phytase production was achieved due to optimization. Supplementation of the medium with inorganic phosphate repressed the enzyme synthesis. When inorganic phosphate was reduced from the cane molasses medium by treatment with calcium chloride, the enzyme production increased. The phytase activity was not affected by the enzyme treatment with trypsin and pepsin. CONCLUSIONS: A twofold increase in phytase production was achieved due to optimization using statistical designs in a cost-effective cane molasses medium. SIGNIFICANCE AND IMPACT OF THE STUDY: Phytase production was doubled due to optimization. The enzyme, being resistant to trypsin and pepsin, thermostable and acid stable, can find application in animal feed industry for improving nutritional status of the feed and combating environmental phosphorus pollution.     

Immunohistochemical Comparative Study of Aggressive and Non-aggressive Central Giant Cell Lesions of the Jaws Based on the Tenascin-C Expression Profile

The purpose of this study was to compare the immunohistochemical expression of tenascin-C (Tn-C) regarding clinicopathological variables and its association with the clinical behavior of central giant cell lesions (CGCLs). Forty-eight paraffin-embedded samples of CGCLs were selected. Based on clinical and radiographic features, the lesions were classified as aggressive (A-CGCLs) and non-aggressive (NA-CGCLs) subtypes. Histological assessment included the microvessel count (MVC), multinucleated giant cell (MGC) count, and the proportion of tissue area involved by mononuclear stromal cells/interstitial fibrosis. Immunoreactivity, immunolocalization, and distribution patterns of Tn-C were studied immunohistochemically. The association between Tn-C expression and clinicopathological characteristics was analyzed separately and adjusted for confounders using logistic regression models. A significantly greater proportion of cases with moderate-to-intense, intracellular, and diffuse staining of Tn-C was observed in A-CGCLs. CGCLs with a size ≥3.3 cm, fast growth, cortical disruption, high MVC/MGC counts, and low interstitial fibrosis showed a significantly greater frequency of moderate-to-intense, intracellular, and diffuse staining. Logistic regression analysis indicated a strong/independent association of these three immunohistochemical parameters with the aggressiveness of lesions. These data appear to suggest a possible role for Tn-C in the etiopathogenesis of CGCLs of the jaws, where its upregulation might favor the destructive behavior of A-CGCLs.     

Giant membrane vesicles as a model to study cellular substrate uptake dissected from metabolism

In order to use giant vesicles for substrate uptake studies in metabolically important tissues, we characterized giant vesicles isolated from heart, liver, skeletal muscle and adipose tissue. We investigated which cell types and which plasma membrane regions are involved in giant vesicle formation and we examined the presence of transporters for metabolic substrates. Analysis of giant vesicles with markers specific for distinct cell types and distinct domains of the plasma membrane reveals that the plasma membrane of parenchymal cells, but not endothelial cells, are the source of the vesicle membranes. In addition, plasma membrane regions enriched in caveolae and involved in docking of recycling vesicles from the endosomal compartment are retained in giant vesicles, indicating that KCl-induced alterations in recycling processes are involved in giant vesicle formation. Giant vesicles contain vesicular lumen consisting of the soluble constituents of the cytoplasm including, fatty-acid binding proteins. Furthermore, giant vesicles isolated from heart, liver, skeletal muscle and adipose tissue are similar in size (10–15 m) and shape and do not contain subcellular organelles, providing the advantage that substrate fluxes in the different organs can be studied independently of the surface/volume ratio but most importantly in the absence of intracellular metabolism.     

High intracellular expression of giant catfish growth hormone under the control of PGK promoter in Saccharomyces cerevisiae

Different yeast plasmid systems containing different promoters such as ADH1, PGK, GAPDH and GAL1, and different selectable markers, such as URA3, TRP1 and leu2-d were compared to obtain the yeast expression system that provides high intracellular expression of giant catfish growth hormone (gcGH). The highest level of gcGH expression was observed in a recombinant yeast under the control of PGK promoter (17.1 mg/l or 1.4 g/0.1 OD). The amount of gcGH was increased six-fold (102.5 mg/l) when cells were grown in a rich medium (YEPD) with the inoculum and medium ratio of 1:1, although the amount of gcGH expression per cell density did not increase (1.0 g/0.1 OD). This indicated that the increased yield of gcGH in rich medium was due to the increased cell density. The aim of the study was to produce high level gcGH in the cells of S. cerevisiae in order to use the yeast cells as potential feed additives to promote growth in giant catfish.     

大熊猫及其近缘种rDNA序列变异和系统进化关系

应用ｒＤＮＡ间隔区Ｓｏｕｔｈｅｒｎ转换技术研究大熊猫及其近缘种的分子系统关系。通过比较大熊猫、小熊猫、黑熊、马来熊、浣熊和猞猁的ｒＤＮＡ间隔区限制性内切酶图谱,用最大似然法和简约法构建它们的分子系统树。结果表明大熊猫与熊具有较近的亲缘关系,与小熊猫和浣熊的亲缘关系较远。