Soil biological attributes in arsenic-contaminated gold mining sites after revegetation

Recovery of arsenic contaminated areas is a challenge society faces throughout the world. Revegetation associated with microbial activity can play an essential role in this process. This work investigated biological attributes in a gold mining area with different arsenic contents at different sites under two types of extant revegetation associated with cover layers of the soil: BS, Brachiaria sp. and Stizolobium sp., and LEGS, Acacia crassicarpa, A. holosericea, A. mangium, Sesbania virgata, Albizia lebbeck and Pseudosamanea guachapele. References were also evaluated, comprising the following three sites: B1, weathered sulfide substrate without revegetation; BM, barren material after gold extraction and PRNH (private reserve of natural heritage), an uncontaminated forest site near the mining area. The organic and microbial biomass carbon contents and substrate-induced respiration rates for these sites from highest to lowest were: PRNH > LEGS > BS > B1 and BM. These attributes were negatively correlated with soluble and total arsenic concentration in the soil. The sites that have undergone revegetation (LEGS and BS) had higher densities of bacteria, fungi, phosphate solubilizers and ammonium oxidizers than the sites without vegetation. Principal component analysis showed that the LEGS site grouped with PRNH, indicating that the use of leguminous species associated with an uncontaminated soil cover layer contributed to the improvement of the biological attributes. With the exception of acid phosphatase, all the biological attributes were indicators of soil recovery, particularly the following: microbial carbon, substrate-induced respiration, density of culturable bacteria, fungi and actinobacteria, phosphate solubilizers and metabolic quotient.     

The dynamics of mitochondrial plasmids in a Hawaiian population of Neurospora intermedia

We analysed the distribution of mitochondrial plasmids among 82 Neurospora intermedia isolates from Hawaii; 74% of the isolates carried the neutral circular plasmid Han-2, whereas 38% contained the linear senescence-causing plasmid kalDNA. The distributions of the two plasmids are independent. There is no significant difference between the Kauaian population of 1972 and that of 1976. To further examine the reasons for this frequency distribution we studied the transmission of both Hawaiian plasmids through the maternal parent in a large series of crosses using non-Kalilo isolates as conidial parents. Plasmids can be lost during the sexual cycle. The Han-2 plasmid is transmitted more efficiently than kalDNA. No clear cases of autonomous or non-autonomous plasmid suppression were observed, so loss can be considered accidental. One Kalilo strain proved to be ineffectual as a maternal parent, and this reduced its ability to transmit kalDNA to the next generation. The dynamic balance of plasmids in natural populations over time is probably a result of the interplay of many forces, including those described in this work and those from several other studies on Neurospora plasmids.     

Antinociceptive and anticonvulsant effects of the monoterpene linalool oxide

Context: Linalool oxide (OXL) (a monoterpene) is found in the essential oils of certain aromatic plants, or it is derived from linalool. The motivation for this work is the lack of psychopharmacological studies on this substance.

Objective: To evaluate OXL’s acute toxicity, along with its anticonvulsant and antinociceptive activities in male Swiss mice.

Material and methods: OXL (50, 100 and 150?mg/kg, i.p.) was investigated for acute toxicity and in the Rota-rod test. Antinociceptive activity was evaluated by the acetic acid-induced writhing test, and by formalin testing. Anticonvulsant effects were demonstrated by testing for pentylenetetrazol (PTZ)-induced seizures and by Maximum Electroshock headset (MES) test. OXL was administered to the animals intraperitoneally 30?min before for pharmacological tests.

Results: OXL showed an LD₅₀ of ～721 (681–765) mg/kg. In the Rota-rod test, it was observed that OXL caused no damage to the animal’s motor coordination. OXL significantly reduced (p?p?p?p?p?p?p?Conclusion: The tested doses of OXL were safe, with no motor impairment, and show clear antinociceptive and anticonvulsant potential. Future investigations with this monoterpene may lead to the development of a new molecule with even higher potency and selectivity.     

Recycling MHC class I molecules and endosomal peptide loading.

MHC class I molecules usually present peptides derived from endogenous antigens that are bound in the endoplasmic reticulum. Loading of exogenous antigens on class I molecules, e.g., in cross-priming, sometimes occurs, but the intracellular location where interaction between the antigenic fragment and class I takes place is unclear. Here we show that measles virus F protein can be presented by class I in transporters associated with antigen processing-independent, NH(4)Cl-sensitive manner, suggesting that class I molecules are able to interact and bind antigen in acidic compartments, like class II molecules. Studies on intracellular transport of green fluorescent protein-tagged class I molecules in living cells confirmed that a small fraction of class I molecules indeed enters classical MHC class II compartments (MIICs) and is transported in MIICs back to the plasma membrane. Fractionation studies show that class I complexes in MIICs contain peptides. The pH in MIIC (around 5.0) is such that efficient peptide exchange can occur. We thus present evidence for a pathway for class I loading that is shared with class II molecules.     

Increased expression of Fcγ receptors II and III on macrophages of rheumatoid arthritis patients results in higher production of tumor necrosis factor α and matrix metalloproteinase

Objective

To evaluate Fcγ receptor (FcγR) expression on synovial macrophages from rheumatoid arthritis (RA) patients and to determine whether this expression correlates with the production of the proinflammatory cytokines tumor necrosis factor α (TNFα), interleukin‐1β (IL‐1β), IL‐12, and matrix metalloproteinase 1 (MMP‐1). We also sought to determine whether mature macrophages from RA patients express aberrant levels of FcγRI, FcγRII, and FcγRIII, and to determine the production of inflammatory mediators after immune complex (IC) stimulation.

Methods

Immunohistochemistry was performed on cryostat sections of synovial biopsy specimens obtained from 27 RA patients and 5 controls. FcγR I, II, and III were detected, as well as the proinflammatory mediators IL‐1, TNFα, IL‐12, and MMP‐1. Monocytes were isolated from the blood of 10 RA patients and 10 healthy controls and cultured for 7 days with macrophage colony‐stimulating factor to obtain macrophages. Using fluorescence‐activated cell sorting, the expression of FcγRI, FcγRII, and FcγRIII was determined. On day 7, macrophages were stimulated with heat‐aggregated gamma globulins (HAGGs) for 24 hours. Production of cytokines was measured using enzyme‐linked immunosorbent assay, and production of gelatinases/collagenases was measured by degradation of fluorescent gelatin.

Results

Immunohistochemistry showed higher FcγRII and FcγRIII expression in RA synovium than in controls. FcγRII and FcγRIII, but not FcγRI, were highly correlated with the number of synovial macrophages. Consistent with this, TNFα expression correlated positively with FcγRIII expression. Moreover, MMP‐1 expression strongly correlated with FcγR I, II, and III expression. Mature macrophages from RA patients showed significantly enhanced expression of FcγRII and FcγRIII compared with controls. Twenty‐four hours after stimulation of RA macrophages with HAGGs, significantly higher production of TNFα and gelatinase/collagenase was measured.

Conclusion

RA synovium and mature RA macrophages express significantly elevated levels of FcγRII and FcγRIII, resulting in much higher production of TNFα and gelatinase/collagenase after IC stimulation. These data suggest that disturbed expression of FcγR on mature synovial macrophages is involved in the pathology of RA.

     

Four human breast cancer cell lines with biallelic inactivating <Emphasis Type="Italic">α-catenin</Emphasis> gene mutations

Mutations of E-cadherin have been identified in half of lobular breast cancers and diffuse-type gastric cancers, two tumor subtypes with remarkably similar pathological appearances including small rounded cells with scant cytoplasm and a diffuse growth pattern. A causal role for E-cadherin gene mutations in the lobular breast cancer phenotype was recently demonstrated in E-cadherin knock-out mice. These observations suggested that another gene in the E-cadherin tumor suppressor pathway might be mutated in lobular breast cancers with wild-type E-cadherin genes. Here, we identified E-cadherin gene mutations exclusively in human breast cancer cell lines that grow with a rounded cell morphology. Using expression analyses and gene mutation analyses, we have identified four biallelic inactivating α-catenin mutations among 55 human breast cancer cell lines. All four α-catenin mutations predicted premature termination of the encoded proteins, and concordantly, none of the four mutant cell lines expressed α-catenin proteins. Importantly, three of the α-catenin mutant cell lines had the rounded cell morphology and all 14 cell lines with the rounded cell morphology had mutations of either E-cadherin or α-catenin. As anticipated, loss of α-catenin protein expression was associated with the lobular subtype in primary breast cancers. Together, our observations suggest that α-catenin may be a new tumor suppressor gene that operates in the E-cadherin tumor suppressor pathway.