Habitat preference in the critically endangered yellow‐tailed woolly monkey (Lagothrix flavicauda) at La Esperanza,Peru

Habitat loss is one of the main threats to wildlife. Therefore, knowledge of habitat use and preference is essential for the design of conservation strategies and identification of priority sites for the protection of endangered species. The yellow‐tailed woolly monkey (Lagothrix flavicauda Humboldt, 1812), categorized as Critically Endangered on the IUCN Red List, is endemic to montane forests in northern Peru where its habitat is greatly threatened. We assessed how habitat use and preference in L. flavicauda are linked to forest structure and composition. The study took place near La Esperanza, in the Amazonas region, Peru. Our objective was to identify characteristics of habitat most utilized by L. flavicauda to provide information that will be useful for the selection of priority sites for conservation measures. Using presence records collected from May 2013 to February 2014 for one group of L. flavicauda, we classified the study site into three different use zones: low‐use, medium‐use, and high‐use. We assessed forest structure and composition for all use zones using 0.1 ha Gentry vegetation transects. Results show high levels of variation in plant species composition across the three use zones. Plants used as food resources had considerably greater density, dominance, and ecological importance in high‐use zones. High‐use zones presented similar structure to medium‐ and low‐use zones; thus it remains difficult to assess the influence of forest structure on habitat preference. We recommend focusing conservation efforts on areas with a similar floristic composition to the high‐use zones recorded in this study and suggest utilizing key alimentation species for reforestation efforts.     

Glycans from Fasciola hepatica Modulate the Host Immune Response and TLR-Induced Maturation of Dendritic Cells

Helminths express various carbohydrate-containing glycoconjugates on their surface, and they release glycan-rich excretion/secretion products that can be very important in their life cycles, infection and pathology. Recent evidence suggests that parasite glycoconjugates could play a role in the evasion of the immune response, leading to a modified Th2-polarized immune response that favors parasite survival in the host. Nevertheless, there is limited information about the nature or function of glycans produced by the trematode Fasciola hepatica, the causative agent of fasciolosis. In this paper, we investigate whether glycosylated molecules from F. hepatica participate in the modulation of host immunity. We also focus on dendritic cells, since they are an important target of immune-modulation by helminths, affecting their activity or function. Our results indicate that glycans from F. hepatica promote the production of IL-4 and IL-10, suppressing IFNγ production. During infection, this parasite is able to induce a semi-mature phenotype of DCs expressing low levels of MHCII and secrete IL-10. Furthermore, we show that parasite glycoconjugates mediate the modulation of LPS-induced maturation of DCs since their oxidation restores the capacity of LPS-treated DCs to secrete high levels of the pro-inflammatory cytokines IL-6 and IL-12/23p40 and low levels of the anti-inflammatory cytokine IL-10. Inhibition assays using carbohydrates suggest that the immune-modulation is mediated, at least in part, by the recognition of a mannose specific-CLR that signals by recruiting the phosphatase Php2. The results presented here contribute to the understanding of the role of parasite glycosylated molecules in the modulation of the host immunity and might be useful in the design of vaccines against fasciolosis.     

Partition of lindane in synthetic and native membranes

Partition coefficients of the insecticide γ-1,2,3,4,5,6-hexachlorocyclohexane (trivially, lindane) were determined in model and native membranes. Partition in egg phosphatidylcholine bilayers decreases linearly with temperature, over a range (10–40°C) at which the lipid is in the liquid-crystalline state. Addition of 50 mol% cholesterol dramatically decreases partition (2100 falls to 100, at 10°C) and abolishes the temperature dependence. First-order phase transitions of dimyristoyl-, dipalmitoyl- and distearoylphosphatidylcholines (DMPC, DPPC and DSPC) are accompanied by a sharp increase in lindane partition. Apparently, the insecticide is easily accommodated in bilayers of short-aliphatic-chain lipids, since the partitions were 2450, 600 and 50 in DMPC, DPPC and DSPC, respectively, at temperatures 10 Cdeg below the midpoint of their transitions. The lindane partition sequence in native membranes is as follows: mitochondria, sarcoplasmic reticulum, myelin, brain microsomes and erythrocytes. This sequence correlates reasonably well with the relative content of cholesterol and is similar in liposomes of total extracted lipids, although the absolute partitions showed decreased values. Therefore, the presence of proteins in native membranes contributes to the insecticide partition, probably by favouring its interaction with lipids.     

The promoters of Arabidopsis thaliana genes AtCOX17-1 and -2, encoding a copper chaperone involved in cytochrome c oxidase biogenesis, are preferentially active in roots and anthers and induced by biotic and abiotic stress

AtCOX17 genes encode Arabidopsis thaliana homologs of the yeast metallochaperone Cox17p, involved in the delivery of copper for cytochrome c oxidase (COX) assembly. Two different AtCOX17 genes, located in chromosomes 1 and 3, are present in the Arabidopsis genome. Sequences available in data banks indicate that the presence of two genes is a common feature in monocots, but not in dicots, suggesting that Arabidopsis genes may be the result of a recent duplication. Sequences upstream from the translation start sites of AtCOX17 genes, which include an intron located in the 5' leader region, were introduced into plants in front of the gus gene. For both genes, expression was localized preferentially in young roots and anthers, but almost 10-fold higher β-glucuronidase activity levels were observed in plants transformed with AtCOX17-1 upstream regions. Both promoters were induced to different extents by wounding, treatment of leaves with the bacterial pathogen Pseudomonas syringae and incubation with agents that produce oxidative stress and metals. AtCOX17-2 showed similar responses to these factors, while AtCOX17-1 was more strongly induced by relatively low (10–100 μ M ) copper. The results indicate that both AtCOX17 genes have similar, though not identical, expression characteristics and suggest the existence in their promoters of elements involved in tissue-specific expression and in responses to factors that may produce mitochondrial or cell damage. It can be speculated that Arabidopsis COX17 accumulates under stress conditions to actively replace damaged or inactive cytochrome c oxidase to sustain cyanide-sensitive respiration in plant cells.     

Adoptive immunotherapy of a mouse colon carcinoma with recombinant interleukin-2 alone or combined with lymphokine-activated killer cells or tumor-immune lymphocytes

Summary We have used a BALB/c colonic adenocarcinoma (C-26) to evaluate the therapeutic potential of recombinant interleukin-2 (rIL-2) at high and low dosages in combination with or without lymphokine-activated killers (LAK) or tumor-specific, immune lymphocytes in either an adjuvant spontaneous or an artificial metastasis system. Most (80%) of the mice that underwent s.c. C-26 tumor excision were shown to die of spontaneous metastasis with lung involvement by 1–4 months after excision. Postsurgical systemic treatment with low-dose rIL-2 (3 × 10⁴ U/day, i.p.) increased the survival rate to 31% as compared to 21% (not significant) in excised controls while administration of high-dose rIL-2 (8 × 10⁴ U/day) led to 53% survival (P <0.01). Both LAK cells and C-26-tumor-immune lymphocytes given during rIL-2 treatment significantly increased the effects of rIL-2 at the low but not at the high-dose, with tumor-immune effectors resulting in the highest percentage (63%) of cures. When mice bearing 3-day artificial lung metastases of C-26 cells were treated with low- or high-dose rIL-2, in combination with or without LAK or tumor-immune lymphocytes, a highly significant reduction or abrogation of the number of lung foci was observed with all treatments, including those involving or tumor-immune lymphocytes alone. Assessment of survival benefit in these mice, however, showed survival prolongation, with 20% cures achieved by low-dose rIL-2 alone and up to 65% cures by LAK in combination with low-dose rIL-2. In this system of artificial metastasis high-dose rIL-2 alone increased the survival time but failed to cure the animals, and the addition of LAK was ineffective whereas that of tumor-immune lymphocytes led to 80% cure. These results suggest that tumorimmune lymphocytes are more effective than LAK when combined with rIL-2 and that caution is necessary in extrapolating findings obtained in artificial metastasis models.     

Partition of DDT in synthetic and native membranes

Partition of DDT (2,2-bis(p-chlorophenyl)-1,1,1-trichloroethane) was determined in artificial and native membranes. Partition in egg phosphatidylcholine of about 260 000 is independent of temperature over the range from 10 to 40 degrees C, in which the lipid is in the liquid-crystalline state. Incorporation of 50 mol% cholesterol decreases DDT partition to about 120 000. First-order phase transitions of dimyristoyl-, dipalmitoyl- and distearoylphosphatidylcholines (DMPC, DPPC and DSPC) are accompanied by a sharp increase in DDT partitioning. Partition decreases symmetrically in the temperature ranges to both sides of the phase transition. The insecticide is preferentially accommodated in bilayers of short-aliphatic-chain lipids, since the partitions were 336 000, 180 000 and 88 000 in DMPC, DPPC and DSPC, respectively, at temperatures 10 Cdeg below the midpoint of their transitions. Partition values in native membranes decrease sequentially as follows: sarcoplasmic reticulum, mitochondria, myelin, brain microsomes and erythrocytes. This sequence is similar to that observed in related liposomes of total extracted lipids, although the absolute partitions showed decreased values. Partition of DDT in native membranes exhibits a negative temperature coefficient not apparent in related lipid dispersions. The effect of intrinsic membrane cholesterol on partition of DDT was also investigated.     

Effect of short-chain primary alcohols on fluidity and activity of sarcoplasmic reticulum membranes

Intramolecular excimer formation with the fluorescent probe 1,3-di(1-pyrenyl)propane, differential scanning calorimetry, and X-ray diffraction were used to assess the effect of ethanol, 1-butanol, and 1-hexanol on the bilayer organization in model membranes, sarcoplasmic reticulum (SR) lipids and native SR membranes. These alcohols have fluidizing effects on membranes and lower the main transition temperature of dimyristoylphosphatidylcholine (DMPC), but only 1-hexanol alters the cooperativity of the phase transition and significantly increases the thickness of DMPC bilayers. The interaction of the three alcohols with the SR Ca2+ pump was also investigated. Hydrolysis of ATP and coupled Ca2+ uptake are differently sensitive to the three alcohols. Whereas ethanol and 1-butanol inhibited the Ca2+ uptake, 1-hexanol stimulated it. Nevertheless, the energetic efficiency of the pump (Ca2+/ATP) is not significantly affected by ethanol or 1-hexanol, but uncoupling was observed with 1-butanol at high concentrations. The different effects of alcohols on the activity of SR membranes rule out an unitary mechanism of action on the basis of fluidity changes induced in the lipid bilayer. Depending on the chain length, the alcohols interact with the SR membranes in different domains, perturbing differently the Ca2+-pump activity.     

Modulation of sarcoplasmic reticulum Ca2+-pump activity by membrane fluidity

Intramolecular excimerization of 1,3-di-1-pyrenylpropane [Py(3)Py] was used to assess the fluidity of sarcoplasmic reticulum membranes (SR); on the basis of the spectral data, the probe incorporates completely inside the membrane probably somewhere close to the polar head groups of phospholipid molecules, however not in the very hydrophobic core. The excimerization rate is very sensitive to lipid phase transitions, as revealed by thermal profiles of dimyristoyl-phosphatidylcholine (DMPC) and dipalmitoylphosphatidylcholine (DPPC) bilayers. Cholesterol abolishes pretransitions and broadens the thermal profiles of the main transitions which vanish completely at 50 mol % sterol. Excimer formation in liposomes of SR total lipid extracts does not show any sharp transitions, as in the case of DMPC and DPPC. However, the plots display discontinuities at about 20 degrees C which are broadened by cholesterol and not observed at 50 mol % sterol. Also cholesterol has been incorporated in native SR membranes by an exchange technique allowing progressive enrichment without changing the phospholipid/protein molar ratio. As in liposomes, discontinuities of excimer formation at 20 degrees C are broadened by cholesterol enrichment. The full activity of uncoupled Ca2+-ATPase is only affected by cholesterol above a molar ratio to phospholipid of 0.4. However, a significant decrease in activity (about 20%) is only noticed at a ratio of 0.6 (the highest technically achieved); at this ratio, about 28 lipid molecules per Ca2+-ATPase are expected to be relatively free from cholesterol interaction. The vesicle structure is still intact at this high ratio, as judged from the absence of basal activity (not Ca2+ stimulated).(ABSTRACT TRUNCATED AT 250 WORDS)