Acute and Chronic Effects of Three Pharmaceutical Drugs on the Tropical Freshwater Cladoceran Ceriodaphnia silvestrii

Water, Air, & Soil Pollution - Phosphorus (P) is an essential element for all living organisms, and plays a major role in many physiological processes. However, in recent years, excessive...     

Identification of candidate genes for paratuberculosis resistance in the native Italian Garfagnina goat breed

Paratuberculosis disease is a chronic bacterial disease infection of ruminants of global relevance, caused by MAP (Mycobacterium avium subsp. paratuberculosis). The present study was conducted on the Garfagnina goat breed that is an Italian native goat population registered on the Tuscan regional repertory of genetic resources at risk of extinction. Forty-eight adult goats (27 serologically positive to MAP-positive and 21 serologically negative to MAP-negative) belonging to a single flock that had experienced annual mortalities due to MAP infection were identified and genotyped with the Illumina GoatSNP60 BeadChip. Diagnosis was achieved by serological tests, as well as post-mortem examination of affected animals. A genome-wide scan was then performed on the individual marker genotypes, in an attempt to identify genomic regions associated with MAP infection disease. Nine significant markers were highlighted and they were located within, or nearby, annotated genes. Two genes found in this study encode are linked to protein kinases that are among the most important enzymes involved in the immune response to Johne’s disease, and four genes are involved in the functions of the Golgi complex.     

Can the extract of Aristolochia argentina Griseb affect the foraging decisions of the leaf cutting ant Acromyrmex lundi (Guérin)? Preliminary assays

ABSTRACT

The aim of this study was to evaluate whether foraging decisions of Acromyrmex lundi in the field are affected by the extract of Aristolochia argentina. A free choice test was performed using Rosa x hybrida leaves treated with the extract and control with acetone. Two leaves (treated and control) were presented on either side of a foraging trail. The percentage of removed material was recorded for 90 minutes of observation on two consecutive days. Dry weight and repellency index were calculated. Ant activity, the percentage of carried leaves and weight data were analyzed using a “t”-test for paired data, and a General Linear Mixed Model test was used to evaluate the different variables and their interactions. A. argentina extract (1%) did not affect the foraging activity of A. lundi, whereas the 5% dose caused significant differences in foraging activity as well as between the factors and the interactions. A repellency index of above 95% was obtained at the 5% dose. The extract of A. argentina could be considered for future management of this insect.     

Rescue of American chestnut with extraspecific genes following its destruction by a naturalized pathogen

Following the near-obliteration of American chestnut (Castanea dentata [Marsh.] Borkh.) by the chestnut blight early in the last century, interest in its restoration has been revived by efforts to develop a blight-resistant form of the species. We summarize progress and outline future steps in two approaches: (1) a system of hybridizing with a blight-resistant chestnut species and then backcrossing repeatedly to recover the American type and (2) transformation of American chestnut with a resistance-conferring transgene followed by propagation and conventional breeding. Several decades of effort have been invested in each approach. More work remains, but results indicate that success is within practical reach. The restoration of C. dentata to its native habitat now appears to be less a matter of time and conjecture than ever before in 90 years of work by public and private entities. The difficult and protracted task of incorporating extraspecific genes for resistance into a tree species with lethal susceptibility to a naturalized pathogen represents perhaps the most extreme of restoration challenges. Its pursuit by a small non-governmental organization supported primarily by philanthropy and volunteers may serve as a model for other species threatened by exotic pathogens or insects.     

Root water uptake of pepper plants (Capsicum annuum L.) under deficit irrigation system

Root water uptake is a component of water balance that has not been clearly understood. This study was carried out in a completely randomized design with three replications under the greenhouse condition at Shahrekord University, Shahrekord, Iran. In this study, the root water uptake (RWU) by pepper plant under various irrigation water levels was investigated. Irrigation treatments included control (full irrigation level, FI) and three deficit irrigation levels, 80%, 60% and 40% of the plant's water requirement called DI₈₀, DI₆₀ and DI₄₀, respectively. A no-plant cover treatment with three replications was also used to measure evaporation from the soil surface. Daily measurements of volumetric soil moisture (VSM) were made at 10 cm intervals of the soil column. The differences between the measured VSM and the VSM in the next day, and evaporation rate at the soil surface at the same layer of the no-plant cover treatment were calculated and, eventually, the RWU in each layer per day was estimated. The results showed that the maximum and minimum RWUs were found in the FI and DI₄₀ treatments, respectively. The averages of root water uptakes in the DI₈₀, DI₆₀, and DI₄₀ treatments were reduced by 17.08%, 48.72% and 68.25%, respectively. Furthermore, in the DI₈₀ treatment, the reduced rate of water uptake was less than the reduced rate of water applied to the plants.     

Potential of Tamarix africana and other halophyte species for phytostabilisation of contaminated salt marsh soils

Purpose

Salt marsh plants are colonising wastes from a steel plant deposited on the Coina River Banks posing a potential contamination risk to the Tagus estuary ecosystem. The objectives of this study were to assess the uptake, accumulation and translocation of hazardous elements/nutrients in three spontaneous halophytic species, to evaluate the capacity of Tamarix africana to stabilise a contaminated salt marsh soil, and to evaluate the ecotoxicity of the pore water and elutriates from phytostabilised soils.

Materials and methods

The work comprises the following: fieldwork collection of soil samples from Coina River (an affluent of Tagus River) bank landfill, estuarine water and spontaneous plants (Aster tripolium, Halimione portulacoides and Sarcocornia sp.), and greenhouse studies (microcosm assay) with T. africana growing in one landfill salt marsh soil, for 97 days, and watered with estuarine water. Soils were analysed for pH, EC, C_organic, NPK, iron and manganese oxides. Soils total (acid digestion) elemental concentrations were determined by ICP/INAA. Estuarine waters, plants roots and shoots (acid digestion), soils available fraction (diluted organic acids extraction-RHIZO or pore water), and salts collected from the T. africana leaves surface were analysed for metals/metalloids (ICP-MS). Ecotoxicity assays were performed in T. africana soil elutriates and pore waters using Artemia franciscana and Brachionus plicatillis.

Results and discussion

Soils were contaminated, containing high total concentrations of arsenic, cadmium, chromium, copper, lead and zinc. However, their concentrations in the available fraction were <4 % of the total. The estuarine waters were contaminated with cadmium, but negligible ecotoxicological effect was observed. The spontaneous plants had significant uptake of the above elements, being mostly stored in the roots. Elemental concentrations in the shoots were within the normal range for plants. These species are not hazardous elements accumulators. Tamarix africana was well adapted to the contaminated saline soils, stored the contaminants in the roots, and had small concentrations of hazardous elements in the shoots. Excretion of hazardous elements by the salt glands was also observed. Elutriates from soils with and without plant did not show ecotoxicity.

Conclusions

The salt marsh species play an important role in the stabilisation of the soils in natural conditions. Tamarix africana showed potential for phytostabilisation of saline-contaminated soils. The low translocation of the elements from roots to shoots and/or active excretion of the elements by the salt glands was a tolerance mechanism in T. africana.

     

Bird species diversity in riparian buffers,row crop fields,and grazed pastures within agriculturally dominated watersheds

In response to concern about the loss of ecosystem services once provided by natural riparian systems, state and federal agencies have established incentive programs for landowners to convert sensitive lands from agricultural to conservation uses. Enhancement of wildlife habitat, while identified as a function of such systems, has often been of secondary importance to soil conservation and water quality objectives. Though greatly important, little consideration has been given to how specific species will respond to the design and management of riparian buffers or other conservation lands. This study compared avian communities within a chronosequence of riparian buffers established on previously cropped or pastured land with those of the nearby matrix land cover types (row crop fields and an intensively grazed pasture). The riparian buffers consisted of native grasses, forbs, and woody vegetation established at three different times (2, 9, and 14+ years prior to survey). At each site, 10 min point counts for breeding birds were conducted using 50 m fixed radius plots, which were visited eight times between May 15 and July 10, 2008. A total of 54 bird species were observed over all of the study sites. The re-established riparian buffers in this study had higher bird abundance, richness, and diversity than the crop and pasture sites. These results suggest that re-establishing native riparian vegetation in areas of intensive agriculture will provide habitat for a broad suite of bird species, but that specific species will reflect successional stage, horizontal and vertical vegetative structure, and compositional diversity of the buffer vegetation. These results emphasize the importance of matching buffer design and management to species requirements if the objectives are to attract specific target species or species groups.     

Forestry insularity effect of four <Emphasis Type="Italic">Mimosa</Emphasis> L. species (Leguminosae-Mimosoideae) on soil nutrients of a Mexican semiarid ecosystem

Information about forestry insularity of plants on soil nutrients will be critical for selecting plant species for agrosilvopastoral or fertility reclamation programs in dry ecosystems. We explored the effects of four Mimosa species (M. lacerata, M. luisana, M. polyantha and M. texana var. filipes) and of rainfall seasonal variation on soil nutrients in a semiarid ecosystem located at the Tehuacán-Cuicatlán Valley, Mexico. Soil samples were taken from outside and under the canopy at three positions (trunk, middle, edge) in all four Mimosa species; ten plants per species. The soil pH, organic matter (SOM), organic carbon (SOC), total nitrogen (Nt), available phosphorus (Pi), and major cations (Ca, Mg, K and Na) were determined. Our results showed that Mimosa species improve the soil under their canopies creating fertile islands with higher SOM, SOC, total N and Pi cycling than the soil in open areas (OA). The insularity effect was significantly species-dependent, where SOM, SOC, Nt and Pi decreased consistently from trunk to OA in all four Mimosa species; however, magnitude varied among species. Likewise, differences in the quantity of soil cations were observed among Mimosa species; though, an insularity gradient trunk-open area was not observed. All these effects were consistent across the species studied and showed little seasonal variability, suggesting a strong forestry insularity of Mimosa species on soil fertility. Of all the four Mimosa species studied, M. lacerata was the most effective in accumulating SOM and nutrients in the soil, for which it would be a good option to implement in agrosilvopastoral or fertility reclamation programs in this semiarid ecosystem.     

Short-term recovery of soil functional parameters and edaphic macro-arthropod community after a forest fire

Background, aim and scope  Forest fires can result in severe economic and environmental consequences, and little is known about the ecological patterns and processes that may lead to the recovery of burnt areas. In the last decades, Portugal has been the Southern European country with the highest number of fire events and with the highest burnt area per hectare. With this work, we proposed to study the effect of a forest fire on the terrestrial ecosystem. More specifically, this work intended to evaluate the short-term recovery of several soil chemical, biochemical (microbial enzymatic activities) and biological (edaphic macro-arthropod community) variables in a burnt pine tree forest area. Methodology  Soil and macro-arthropod sampling was carried out in a burnt area (transects BI, BII and BIII) and in a neighbouring unburnt area (U) 3 and 8 months after the fire, coinciding with autumn and spring. Soil was collected for the determination of physical (pH and conductivity) and chemical parameters (moisture and organic matter) and soil enzymes (cellulase, acid phosphatase and nitrogen mineralisation rate). Edaphic macro-fauna was captured using pitfall traps. Results  Univariate and multivariate statistics revealed, overall, that burnt sites displayed lower acid phosphatase and cellulase activities and higher conductivity and pH values than the unburnt area. There was a recovery in the measured soil parameters between autumn and spring in the most interior parts of the burnt areas (BII and BIII), but the outer transect (BI, close to a road) still displayed considerable differences to the remaining burnt transects as well as to the unburnt area. A total of 47 macro-arthropod taxa were captured in both seasons, with Linyphiidae spiders (20.2%) and insect families Formicidae (13.4%) and Staphylinidae (11.9%) being the most abundant. Dominance by some taxa was overall stronger in the burnt than in the unburnt area, although dominant taxa varied between seasons. In autumn, the burnt area was dominated by ants and had also a high abundance of scavengers, carrion feeders and some ground active hunters. In spring, there was a general increase in taxa diversity, richness, and total catches; in the burnt area, there was a re-colonisation by several organisms sensitive to litter quality, such as isopods and pseudoscorpions, particularly in the outer transect (closest to the unburnt area). Discussion  Differences in soil parameters between burnt and unburnt areas were most likely due to the deposition of nutrient-rich alkaline ashes. However, low cellulase activity in the outer part of the burnt area (BI) indicated compromised microbial activity in both sampling seasons. Recovery of soil functional parameters was delayed in the outer zone of the burnt area because of (i) fire intensity in that area or (ii) proximity to the road (enhancing erosion and exposure to contaminants). The pattern of arthropod re-colonisation of the burnt area followed the inverse recovery pattern (from the outer zone to the inner zone), stressing the primary role of the adjacent unburnt area as a source of potentially colonizing organisms. Conclusions  Direct and indirect effects of fire on soil parameters (soil alkalinisation and nutrient enrichment) and edaphic fauna had a short-term persistence in the burnt area, and signs of recovery were evident 8 months after the fire (spring). The adjacent unburnt area seemed to act as an important source of arthropod colonisers. Recommendations and perspectives  More prolonged studies on the recovery of soil functional parameters and arthropod community structure are required to understand long-term re-colonisation patterns. Researchers and authorities should also endeavour in the implementation of measures that favour and protect survivors and new indigenous colonisers (microbes, plants and animals) after a forest fire.