Amino acid sequence versus morphological data and the interordinal relationships of mammals

To a large extent, the mutual affinities of the mammalian orders continue to puzzle systematists, even though comparative anatomy and amino acid sequencing offer a massive data base from which these relationships could potentially be adduced. In the present paper the consistency index--the number of character states less the number of characters in a data set, divided by the total number of changes in the character states on a cladogram--was used to examine the relative resolving powers of recently published morphological and molecular- sequence data. Consistency indices were calculated for previously published alpha crystallin A chain and myoglobin amino acid-sequence cladograms and for four original amino acid-sequence cladograms (alpha crystallin A, myoglobin, and alpha and beta hemoglobin); these were found to be comparable to the consistency indices of morphologically based cladograms. Qualitative comparisons between the morphologically based and molecularly based trees were also made; only moderate congruence between the two was observed. Moreover, there was a general lack of congruence between the cladograms specified by each of the four proteins. Amino acid-sequence and morphological data agreed on the placement of edentates as an early eutherian offshoot and on the grouping of hyracoids, proboscideans, and sirenians. Otherwise there was only limited congruence: morphology strongly supported the grouping of lagomorphs and rodents and the alliance of pholidotes and edentates, but sequence analyses did not. The placement of tubulidentates differed widely among proteins. Morphology indicated the close association of sirenians with proboscideans; proteins suggested a pairing of sirenians with hyracoids. Sequence data did not identify many (morphologically well-diagnosed) orders as monophyletic (e.g., Lagomorpha).(ABSTRACT TRUNCATED AT 250 WORDS)      

Comparison of HPLC and colorimetric methods for measuring cellulolytic activity

Summary The sugars released during a standard filter paper assay were quantified by colorimetric (Dinitrosalicylic acid and Nelson and Somogyi) and HPLC methods. It was found that the composition of the sugars present in the hydrolysates greatly influenced the final filter paper units of activity obtained. In a -glucosidase deficient cellulase system the filter paper activity reported using colorimetric methods could be enhanced by adding supplemental amounts of -glucosidase. However, HPLC methods of quantitating filter paper activity were not affected provided the accumulated cellobiose did not inhibit the cellulase enzymes. Glucose oxidase methods of assaying -glucosidase activity were also influenced by wood decomposition products present in the culture filtrates. HPLC methods of quantifying hydrolysates gave the most representative values of the hydrolytic potential of the cellulase enzyme complex.     

Transferable 5-nitroimidazole resistance in the Bacteroides fragilis group

We report the characterization of a strain of Bacteroides vulgatus, BV17, that exhibits a moderate resistance to 5-nitroimidazoles and carries plasmids of 4.5, 5, 7.7, and 56 kb. A genetic determinant involved in this resistance is carried by the 7.7 +/- 0.2-kb plasmid (pIP417). This plasmid can be introduced and replicated in a sensitive strain of B. fragilis 638R by transformation or by conjugation. In the latter case, the transfer may involve mobilization by the 56-kb conjugative plasmid (pIP418) regularly found in transconjugants but not in transformants.     

Histological and histochemical study of the uropygial gland of chimango caracara (Milvago chimango vieillot, 1816)

The uropygial glands of birds are sebaceous organs that contribute to the water-repellent properties of the feather coat. We studied the histological and histochemical characteristics of the uropygial gland of chimango caracara using hematoxylin and eosin (H & E), Gomori´s trichrome, orcein, Gomori´s reticulin, periodic acid-Schiff (PAS), Alcian blue (AB) and a variety of lectins. The gland is composed of two lobes and a papilla with 20 downy feathers. It is surrounded by a capsule of dense connective tissue that contains elastic, reticular and smooth muscle fibers. The papilla is delicate and has two excretory ducts. The gland mass relative to body mass was 0.143%. Both adenomer cells and their secretions were stained with Sudan IV, PAS and AB, and were positive for numerous lectins that indicated the presence of lipids and carbohydrates. Immunohistochemical techniques to detect PCNA confirmed cell proliferation in the basal stratum of the adenomer cells. The lipids and glycoconjugates secreted by the uropygial gland serve numerous functions including protection against microorganisms.     

Ergosterol — A measure of fungal growth in wood for staining and pitch control fungi

Summary A modified ergosterol analysis method, including a simultaneous saponification and refluxing extraction procedure along with HPLC quantification, was used to measure fungal colonization rate in wood. In liquid media the ergosterol content of the mycelia was measured and correlated to the fungal dry weight. In work on investigating staining fungal proteinase production on wood, ergosterol values were used to monitor fungal growth and to determine when maximum proteinase activity occurred. Similarly, we correlated ergosterol values with the decrease of wood lipids during pitch control fungal colonization.     

Peaks of in situ N2O emissions are influenced by N2O‐producing and reducing microbial communities across arable soils

Agriculture is the main source of terrestrial N₂O emissions, a potent greenhouse gas and the main cause of ozone depletion. The reduction of N₂O into N₂ by microorganisms carrying the nitrous oxide reductase gene (nosZ) is the only known biological process eliminating this greenhouse gas. Recent studies showed that a previously unknown clade of N₂O‐reducers (nosZII) was related to the potential capacity of the soil to act as a N₂O sink. However, little is known about how this group responds to different agricultural practices. Here, we investigated how N₂O‐producers and N₂O‐reducers were affected by agricultural practices across a range of cropping systems in order to evaluate the consequences for N₂O emissions. The abundance of both ammonia‐oxidizers and denitrifiers was quantified by real‐time qPCR, and the diversity of nosZ clades was determined by 454 pyrosequencing. Denitrification and nitrification potential activities as well as in situ N₂O emissions were also assessed. Overall, greatest differences in microbial activity, diversity, and abundance were observed between sites rather than between agricultural practices at each site. To better understand the contribution of abiotic and biotic factors to the in situ N₂O emissions, we subdivided more than 59,000 field measurements into fractions from low to high rates. We found that the low N₂O emission rates were mainly explained by variation in soil properties (up to 59%), while the high rates were explained by variation in abundance and diversity of microbial communities (up to 68%). Notably, the diversity of the nosZII clade but not of the nosZI clade was important to explain the variation of in situ N₂O emissions. Altogether, these results lay the foundation for a better understanding of the response of N₂O‐reducing bacteria to agricultural practices and how it may ultimately affect N₂O emissions.     

Identification and characterization of a prevacuolar compartment in stigmas of nicotiana alata

The stigmas of the ornamental tobacco plant Nicotiana alata accumulate large quantities of a series of 6-kD proteinase inhibitors (PIs) in the central vacuole that are derived from a 40-kD precursor protein, Na-PI. The sorting information that directs Na-PI to the vacuole is likely to reside in a C-terminal propeptide domain of 25 amino acids that forms an amphipathic alpha helix. Using cell fractionation techniques, we have examined transit of Na-PI through the endomembrane system and have identified a prevacuolar compartment that contains Na-PI with an intact targeting signal. In contrast, the targeting signal is not present on the predominant form of Na-PI in the vacuole. The prevacuolar compartment is marked by the presence of homologs of both the t-SNARE, PEP12p, and the putative vacuolar sorting receptor BP-80. Cross-linking and affinity precipitation studies revealed that Na-PI associates with BP-80 within this compartment, providing in vivo evidence for the function of BP-80 as a sorting receptor for a protein with a C-terminal vacuolar targeting signal.     

Tumor‐associated macrophages (TAMs) depend on ZEB1 for their cancer‐promoting roles

Accumulation of tumor‐associated macrophages (TAMs) associates with malignant progression in cancer. However, the mechanisms that drive the pro‐tumor functions of TAMs are not fully understood. ZEB1 is best known for driving an epithelial‐to‐mesenchymal transition (EMT) in cancer cells to promote tumor progression. However, a role for ZEB1 in macrophages and TAMs has not been studied. Here we describe that TAMs require ZEB1 for their tumor‐promoting and chemotherapy resistance functions in a mouse model of ovarian cancer. Only TAMs that expressed full levels of Zeb1 accelerated tumor growth. Mechanistically, ZEB1 expression in TAMs induced their polarization toward an F4/80^low pro‐tumor phenotype, including direct activation of Ccr2. In turn, expression of ZEB1 by TAMs induced Ccl2, Cd74, and a mesenchymal/stem‐like phenotype in cancer cells. In human ovarian carcinomas, TAM infiltration and CCR2 expression correlated with ZEB1 in tumor cells, where along with CCL2 and CD74 determined poorer prognosis. Importantly, ZEB1 in TAMs was a factor of poorer survival in human ovarian carcinomas. These data establish ZEB1 as a key factor in the tumor microenvironment and for maintaining TAMs’ tumor‐promoting functions.     

Mangrove reforestation: greening or grabbing coastal zones and deltas? Case studies in Senegal§

Besides their important contribution to global biodiversity, mangroves provide many services. Nevertheless, due to an increase of human activities and to climate change, in less than 20 years these ecosystems have lost one fifth of their global surface area. In response to this decrease, mangrove reforestation incentives have spread throughout the world. The scientific and societal legitimacy of reforestation actions still remain in question. Focusing on two case studies, the Saloum Delta and Lower Casamance, Senegal, our methodology was mainly based on the analysis of environmental narratives and discourses between 2009 and 2013, and on reforestation campaigns conducted by NGOs. We highlight the complexity of the system of values associated with the mangroves, as well as the positive and negative interactions between the services. Even although the reforestation campaigns were generally successful in terms of reforested surfaces and international visibility, they were poor in terms of biological and cultural diversities and led to spatial injustice. Moreover, the extensive reforestation with a unique mangrove species, Rhizophora mangle, was perceived as means of ‘green grabbing’, and the simultaneous buying of carbon tax by industrial conglomerates induced disempowerment of the local communities. More integrated research programmes must be developed towards the extensive knowledge of the mangroves.