Wood decomposition in tropical forests is strongly linked to the terrestrial carbon cycle. Our understanding of the successional changes in wood decomposition in diverse tropical forests is still ...limited. In this study, we tested the hypothesis that fine wood decomposition rates decline with the increasing age of successional forests due to the interspecific variation in wood density and changes in species composition. We studied fine wood decomposition in a chronosequence of tropical forests representing four successional phases in southern Mexico. Wood segments (1–7.5 cm diameter) from 30 dominant species (wood density range 0.34–0.83 g cm
−3
) were left on the ground for decomposition, and samples were recollected at different time intervals for three years. We used a modified negative exponential model by introducing the power parameter (
p
) that allowed for a time-dependent decomposition rate (
k
). Average
k
within a successional phase ranged from 0.22 to 0.39 yr
−1
and declined gradually with the increase in forest age. We found a significant negative correlation between wood density and decomposition rate constants. The
k
species
ranged from 0.07 to 1.11 yr
−1
, whereas p-parameters varied between 0.65 and 1.42. Trees such as
Bursera simaruba
, and
Cascabela gaumeri
decomposed faster, while
Eugenia ibarrae
, and
Pouteria reticulata
decomposed slower. Average fine woody debris inputs ranged from 1.2 to 3.7 Mg ha
−1
yr
−1
which increased with forest age. Increasing production and declining decomposition rates during succession contribute to the higher accumulation of deadwood in primary forests. The results on generalized, age- and species-specific wood decay parameters have important implications in simulating carbon dynamics of the changing tropical forests.
Nanoscience and nanotechnology have been shown to have the capacity to help study, manipulation,design, and synthesis of new nano‐sized materials to manufacture new products with desirable features ...never seen before. The unique properties of materials at nanoscale opens an excellent possibility for nanotechnology to be used in soil environmental remediation, and water, and air decontamination. In crop management, nanomaterials are used to regulate the controlled release of nutrients, fertilizers, and pesticides. However, it is not only necessary to expose the positive effects by the application of the nanomaterials but also to demonstrate the impacts on soil and nontarget organisms (plants, mesofauna, macrofauna, and soil microbiota). In this context, pieces of evidence on the adverse effects of engineered nanoparticles (ENP) on the physicochemical and biological properties of soils are discussed in this paper. We have found a diversity of contradictory results. The summaries, findings, and conclusions of most of the investigations support the need to understand the biological or physicochemical transformation and transport of ENP in soil, and in the plant‐organism relationship. Better understanding regarding the soil biota coupled with the ecological ENP behavior could ensure the safe use of ENP. Nanomaterials can change the physicochemical and biological properties of the soils; consequently, long‐term in situ field trials are required, and meanwhile, land‐application of nanomaterials should be limited to scientific experiments to fill knowledge gaps to not jeopardize the global food production or the environment and worldwide human health.
Although plastic pollution happens globally, the micro- (<5 mm) and macroplastic (5-150 mm) transfer of plastic to terrestrial species relevant to human consumption has not been examined. We provide ...first-time evidence for micro- and macroplastic transfer from soil to chickens in traditional Mayan home gardens in Southeast Mexico where waste mismanagement is common. We assessed micro- and macroplastic in soil, earthworm casts, chicken feces, crops and gizzards (used for human consumption). Microplastic concentrations increased from soil (0.87 ± 1.9 particles g
), to earthworm casts (14.8 ± 28.8 particles g
), to chicken feces (129.8 ± 82.3 particles g
). Chicken gizzards contained 10.2 ± 13.8 microplastic particles, while no microplastic was found in crops. An average of 45.82 ± 42.6 macroplastic particles were found per gizzard and 11 ± 15.3 macroplastic particles per crop, with 1-10 mm particles being significantly more abundant per gizzard (31.8 ± 27.27 particles) compared to the crop (1 ± 2.2 particles). The data show that micro- and macroplastic are capable of entering terrestrial food webs.
Polylactic acid (PLA) bioplastic was introduced to the market as an environmentally friendly potential solution for plastic pollution. However, the effects of bioplastic debris mixed with composts on ...soil macroinvertebrates, plant growth and soil conditions are still unknown. Soil macroinvertebrates are soil health indicators. A reduction in their abundance is a sign of soil degradation. The objectives of this study were (i) to assess PLA debris in greenhouse composts, and (ii) to test the ecotoxicological effects of PLA debris mixed with compost on
, a soil organism model, and on
a plant growth model. The study was comprised of three stages: (1) determine the PLA debris size distribution in composts; (2) assess the ecotoxicological effects of real-world concentrations (0% to 5%) of PLA mixed with compost on earthworm mortality and reproduction; and (3) assess the influence of compost mixed with real-world PLA concentrations on plant growth and physicochemical soil conditions. One percent of PLA debris was found in green composts, 40% of composted PLA debris measured between 1-10 mm, with a concentration of 82.8 ± 17.4 microplastics.gram
compost. A concentration of 1% PLA in composts resulted in significant mortality in earthworms. No significant effects of PLA mixed with composts were observed on plant growth or soil physicochemical conditions. Further studies are required in order to test the effect of this biopolymer on different earthworm and plant' species.
•Our findings provide support to the concepts of inflammation in clinical practice.•The inflammation-based risk score has got the ability to predict in-hospital mortality in acute coronary ...syndrome.•Approximately one-fifth of these patients had severe systemic inflammation.•The patients with severe inflammation had significantly poorer in-hospital outcomes.•Presence of severe inflammation may provide reasons for new anti-inflammatory strategies.
Accurate assessment of inflammatory status of patients during acute coronary syndrome (ACS) has become of great importance in their risk classification and in the research of new anti-inflammatory therapies.
The study cohort included 7396 patients with ACS. We sought to derive and internally validate an inflammation-based score that included high-sensitivity C-reactive protein, white blood cell count, and serum albumin level at admission to evaluate the predictive role of systemic inflammation in the clinical outcome of these patients. We randomly assigned patients into derivation (66.6%) and validation (33.4%) cohorts. A total of four categories of systemic inflammation were defined.
Assessed individually, the three biomarkers were associated with a higher rate of in-hospital mortality. When we combined them into an inflammation score, in-hospital mortality was significantly different across the four categories of inflammation in the derivation cohort (1.8%, 2.8%, 4.1%, and 13.8% for without, mild, moderate, and severe inflammation, respectively; p<0.0001, C-statistic, 0.71). These results were similar in the validation cohort (1.1%, 2.9%, 5.2%, and 12.6%, respectively; p<0.0001, C-statistic, 0.71). After multivariate adjustment, only the category of severe systemic inflammation was associated with a threefold increased risk of in-hospital mortality (odds ratios 3.02, p<0.0001) and was the most powerful predictor of mortality. In the whole cohort, after subsetting patients based on GRACE risk score, the severe inflammation category was associated with a significant increase of in-hospital mortality across all sub-groups, mainly in patients with higher GRACE risk score. The inflammation-based risk score reclassified 25.3% of the population. The net reclassification index was 8.2% (p=0.001).
A risk score system based on biomarkers of inflammation readily available at admission in patients with ACS, could better assess the inflammatory status and predict in-hospital mortality, as well as severe systemic inflammation that contributes to a worse outcome independently of clinical risk factors.
Agroforestry for production and ecosystem health is a centuries-old form of ecosystem management used in many cultures indigenous to Mesoamerica, yet implications of such practices for biodiversity ...conservation are not well understood. Agroforestry systems were studied using interviews of farmers and field surveys of tree and bird diversity in three communities surrounding the Calakmul Biosphere Reserve in Campeche, Mexico to examine how differences in forest management practices affect forest biodiversity. Tree diversity and bird species richness were higher in areas surrounding communities that generated a greater variety of forest products and that cultivated “restoration trees,” species planted to aid in regeneration of mature forest. We conclude that traditional ecosystem management methods in areas surrounding natural reserves as practiced by inhabitants who depend on resources in the reserve for survival are compatible with maintaining and perhaps enhancing diversity of bird and tree communities at the site level.
Soil invertebrates are important for diverse soil ecosystem services, which are jeopardized by pesticides and microplastics. In the present study, we aimed to assess above-ground invertebrates’ ...morphospecies abundance in the presence of glyphosate (GLY), its main metabolite aminomethylphosphonic acid (AMPA), and microplastics (MPs). Three land-use systems were analyzed: agricultural systems with and without plastic mulch and pesticides (AwPM, AwoPM) and natural unmanaged farming systems (UF). Soil GLY, AMPA, MP concentrations and above-ground invertebrates were quantified. GLY concentrations were also assessed inside invertebrate tissues. GLY, AMPA and the highest concentration of GLY in invertebrates’ tissue were found only in AwoPM at 0.14–0.45 mg kg−1, 0.12–0.94 mg kg−1 and 0.03–0.26 mg kg−1, respectively. MPs were present as follows: AwPM system (100%, 400–2000 particles kg−1) > AwoPM (70.8%, 200–1000 particles kg−1) > UF (37.5%, 200–400 particles kg−1). No significant correlations were found between soil MPs, GLY and AMPA. There was a significant correlation between MPs and morphospecies from the order Entomobrymorpha (Collembola, R = 0.61, p < 0.05). Limnophila, Mesogastropoda (Gastropoda) and Siphonaptera morphospecies were only present in the UF system. GLY in invertebrate tissue was inversely correlated with soil GLY (R = −0.73, p < 0.05) and AMPA (R = −0.59, p < 0.05). Further investigations are required to understand these phenomena.
Estimar el contenido de carbono en suelo y vegetación es una tarea onerosa, de aquí la importancia de desarrollar métodos confiables para su estimación utilizando bases de datos con reducida ...información. El objetivo del presente estudio fue estimar el contenido de carbono orgánico del suelo (COS) y el carbono de la vegetación (COV) para el estado de Campeche, México. Desarrollando una metodología en condiciones de poca disponibilidad de información. Se utilizaron las bases de datos oficiales disponibles en México del Instituto Nacional de Estadística y Geografía (INEGI). La principal limitante de los datos del INEGI para la estimación del COS por unidad de área, es la falta de información sobre la densidad aparente del suelo. Por lo tanto, la densidad aparente para los suelos se obtuvo a través de regresiones lineales múltiples, utilizando datos de 37 perfiles de suelo que fueron descritos en 10 de los 14 grupos de suelos reportados en el Estado. El COS ha-1 para cada perfil/unidad de suelo para todo el estado, se calculó siguiendo la fórmula propuesta por el Panel Intergubernamental de Cambio Climático. La estimación del COV se realizó usando datos de la superficie ocupada por tipo de vegetación del INEGI, reclasificando los tipos de vegetación de 58 a 23, utilizando los valores de COV por ha. La reducción del coeficiente de variación en comparación con los resultados de otros estudios, muestra que la metodología aplicada produce estimaciones más precisas. El carbono total estimado para el estado de Campeche fue de 765 417 Gg, de los cuales 64.1% correspondió a COS y 35.9% a COV.
Fine root production, turnover, and decomposition are fundamental rhizosphere processes that can vary when young forest ecosystems pass through different phases of succession towards maturity. To ...assess these changes during succession, we applied ingrowth bag and sequential coring methods for fine root production and a modified negative exponential model for fine root decomposition at four phases of tropical forest chronosequence: 1) young secondary forests of about 8 years, 2) medium secondary forests of 15 years, 3) advanced secondary forests of 25 years, and 4) old-growth primary forests of >100 years. Primary forests stored higher fine root biomass than secondary forests but the average fine root productivity did not differ statistically between successional phases. Fine root turnover rates were >1 yr−1 for all the phases of succession, indicating that the turnover was higher than the standing fine root biomass. Fine root decay models showed that the decomposition rates did not differ significantly between successional phases. Furthermore, fine root production and mortality correlated positively to soil organic carbon concentrations. Our results showed that fine root productivity and turnover rates in secondary forests get to PF level from the younger phases of succession. The results have important implications in understanding the successional patterns regarding belowground resource allocation, nutrient turnover, and soil organic carbon sequestration in the constantly changing tropical forests ecosystems.
•Old-growth primary forests presented higher fine root biomass stocks than secondary forests.•Fine root production, mortality, turnover, and decomposition rates did not differ between forest successional phases.•Fine root turnover rates were >1 yr−1 for all the phases of succession.•Fine root production and mortality correlated positively with soil organic carbon concentrations.
The application of bioengineering to plants for production of biological products for human and animal use has expanded in recent years. The reasons for this expansion are several and include ...advances in the technology for novel production systems and the need for very large quantities of therapeutic proteins. The process of growing pharmaceutical proteins in plants, extracting, and purifying is a hard task considering the lack of available information concerning these topics. In this work, a recombinant murine monoclonal antibody specific for the hepatitis B surface antigen, expressed in stably transformed transgenic
Nicotiana tabacum plants, was purified by means of a recombinant protein A Streamline chromatography as the main purification step. The antibody expression level varied with the age of the plants and the number of harvests from 40 to 15
μg/ml and the maximum process yield was about 25
mg of plantibody/kg of biomass. Protein A Streamline chromatography was successfully used in the purification process yielding a recovery of about 60% and a plantibody SDS–PAGE purity of over 90% but unexpectedly, previous clarification steps could not be totally avoided. The amino acid sequence recognized by this affinity purified plantibody was similar to its murine counterpart verifying the potentiality of plants to replace animals or bioreactors for large-scale production of this monoclonal antibody.
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