Agronomic Management of Indigenous Mycorrhizas

Many of the advantages conferred to plants by arbuscular mycorrhiza (AM) are associated to the ability of AM plants to explore a greater volume of soil through the extraradical mycelium. Sieverding (1991) estimates that for each centimetre of colonized root there is an increase of 15 cm3 on the volume of soil explored, this value can increase to 200 cm3 depending on the circumstances. Due to the enhancement of the volume of soil explored and the ability of the extraradical mycelium to absorb and translocate nutrients to the plant, one of the most obvious and important advantages resulting from mycorrhization is the uptake of nutrients. Among of which the ones that have immobilized forms in soil, such as P, assume particular significance. Besides this, many other benefits are recognized for AM plants (Gupta et al, 2000): water stress alleviation (Augé, 2004; Cho et al, 2006), protection from root pathogens (Graham, 2001), tolerance to toxic heavy metals and phytoremediation (Audet and Charest, 2006; Göhre and Paszkowski, 2006), tolerance to adverse conditions such as very high or low temperature, high salinity (Sannazzaro et al, 2006), high or low pH (Yano and Takaki, 2005) or better performance during transplantation shock (Subhan et al, 1998). The extraradical hyphae also stabilize soil aggregates by both enmeshing soil particles (Miller e Jastrow, 1992) and producing a glycoprotein, golmalin, which may act as a glue-like substance to adhere soil particles together (Wright and Upadhyaya, 1998). Despite the ubiquous distribution of mycorrhizal fungi (Smith and Read, 2000) and only a relative specificity between host plants and fungal isolates (McGonigle and Fitter, 1990), the obligate nature of the symbiosis implies the establishment of a plant propagation system, either under greenhouse conditions or in vitro laboratory propagation. These techniques result in high inoculum production costs, which still remains a serious problem since they are not competitive with production costs of phosphorus fertilizer. Even if farmers understand the significance of sustainable agricultural systems, the reduction of phosphorus inputs by using AM fungal inocula alone cannot be justified except, perhaps, in the case of high value crops (Saioto and Marumoto, 2002). Nurseries, high income horticulture farmers and no-agricultural application such as rehabilitation of degraded or devegetated landscapes are examples of areas where the use of commercial inoculum is current. Another serious problem is quality of commercial available products concerning guarantee of phatogene free content, storage conditions, most effective application methods and what types to use. Besides the information provided by suppliers about its inoculum can be deceiving, as from the usually referred total counts, only a fraction may be effective for a particular plant or in specific soil conditions. Gianinazzi and Vosátka (2004) assume that progress should be made towards registration procedures that stimulate the development of the mycorrhizal industry. Some on-farm inoculum production and application methods have been studied, allowing farmers to produce locally adapted isolates and generate a taxonomically diverse inoculum (Mohandas et al, 2004; Douds et al, 2005). However the inocula produced this way are not readily processed for mechanical application to the fields, being an obstacle to the utilization in large scale agriculture, especially row crops, moreover it would represent an additional mechanical operation with the corresponding economic and soil compaction costs. It is well recognized that inoculation of AM fungi has a potential significance in not only sustainable crop production, but also environmental conservation. However, the status quo of inoculation is far from practical technology that can be widely used in the field. Together a further basic understanding of the biology and diversity of AM fungi is needed (Abbott at al, 1995; Saito and Marumoto, 2002). Advances in ecology during the past decade have led to a much more detailed understanding of the potential negative consequences of species introductions and the potential for negative ecological consequences of invasions by mycorrhizal fungi is poorly understood. Schwartz et al, (2006) recommend that a careful assessment documenting the need for inoculation, and the likelihood of success, should be conducted prior to inoculation because inoculations are not universally beneficial. Agricultural practices such as crop rotation, tillage, weed control and fertilizer apllication all produce changes in the chemical, physical and biological soil variables and affect the ecological niches available for occupancy by the soil biota, influencing in different ways the symbiosis performance and consequently the inoculum development, shaping changes and upset balance of native populations. The molecular biology tools developed in the latest years have been very important for our perception of these changes, ensuing awareness of management choice implications in AM development. In this context, for extensive farming systems and regarding environmental and economic costs, the identification of agronomic management practices that allow controlled manipulation of the fungal community and capitalization of AM mutualistic effect making use of local inoculum, seem to be a wise option for mycorrhiza promotion and development of sustainable crop production

Effect of inulin as a prebiotic to improve growth and counts of a probiotic cocktail in fermented skim milk

Inulin was used as a prebiotic to improve quality of skim milk fermented by pure cultures of Lactobacillus acidophilus, Lactobacillus rhamnosus, Lactobacillus bulgaricus and Bifidobacterium lactis, binary co-cultures with Streptococcus thermophilus, or a cocktail containing all them

Effect of inulin as prebiotic and synbiotic interactions between probiotics to improve fermented milk firmness

We investigated the inulin capability to improve the firmness, after short-term cold storage, of skim milk fermented by L. acidophilus, L. rhamnosus, Lactobacillus bulgaricus and B. lactis, either in pure cultures or in binary co-cultures with S. thermophilus or in a cocktail containing all them

Use of lactulose as prebiotic and its influence on the growth, acidification profile and viable counts of different probiotics in fermented skim milk

The present study explores the effects of lactulose on the acidification kinetics, post-acidification, growth and metabolism of binary co-cultures of L. bulgaricus, L. acidophilus, L. rhamnosus and B. lactis with S. thermophilus, as well on their survival during skim milk fermentation

Characterization of Lactiplantibacillus plantarum Tw226 strain and its use for the production of a new membrane-bound biosurfactant

This study aimed to evaluate the viability for biotechnological uses of a new cell-bound biosurfactant produced by a lactic acid bacterium isolated from the intestinal tract of Odontesthes bonariensis. For this purpose, the bacterial strain was characterized, and the conditions for biosurfactant production were optimized. Moreover, the biosurfactant was chemically characterized, and its possible use as an emulsi-fying agent assessed. The bacterium was identified as Lactiplantibacillus plantarum Tw226 and qualified as safe for biotechnological uses according to the genomic and antibiotic resistance studies. The agitation did not influence the biosurfactant productivity, which reached its maximum value, using MRS medium as a nutrient source, before 48 h of incubation at a temperature of 35 degrees C. The glyco-lipo-peptide nature of the biosurfactant was confirmed by the analysis of its chemical composition. It showed stable surface activity in the pH range of 5-7 and a remarkable functionality as an emulsifier, especially in emulsions containing NaCl. (c) 2022 Elsevier B.V. All rights reserved

Use of cytogenetic indicators in radiobiology

The study of ionising radiation has systematically relied on cytogenetic indicators to evaluate the biological effects and has led to theoretical approaches to explain observations associated with radiation exposure. In many of the early studies on radiobiology, the induction of chromosomal aberrations was the method of choice to evaluate dose-response relationships. But progressively, this and other cytogenetic biomarkers were used to obtain mechanistic insight on the biological effects induced by radiation. This paper attempts to give a view on the use of cytogenetic indicators in the study of various radiation-related phenomena, including radiation dosimetry, mechanisms involved in the various cellular responses to radiation, such as bystander effects, chromosomal instability and adaptive response, as well as DNA repair pathways. One future direction may involve the use of cytogenetic indicators to evaluate various molecular determinants in individuals' susceptibility to radiation, using other techniques such as fluorescence in situ hybridisation (FISH) and linking them to specific gene functions and single nucleotide polymorphisms

Prevalência e fatores associados à prematuridade entre gestantes submetidas à inibição de trabalho de parto prematuro Prevalence and risk factors associated to preterm delivery among pregnant women submitted to preterm labor inhibition treatment

OBJETIVOS: identificar a prevalência de parto prematuro em gestantes submetidas ao tratamento de inibição de trabalho de parto prematuro e analisar os fatores associados. MÉTODOS: estudo transversal, com dados coletados de 163 prontuários de gestantes submetidas a tratamento de inibição de trabalho de parto prematuro atendidas em 1995-2000, no Hospital Universitário da Universidade de São Paulo, Brasil. A variável dependente constituiu-se na ocorrência de parto prematuro e as independentes foram: idade, escolaridade, ocupação, paridade, companheiro, tabagismo, infecção urinária prévia, número de consultas pré-natal e intervalo interpartal. A análise foi feita pelo teste de associação pelo Qui-quadrado e modelos de regressão logística univariado e múltiplo. RESULTADOS: 66,3% das gestantes tiveram filhos prematuros e, em 22,7% dos casos, o parto ocorreu antes de 34 semanas. Houve associação estatística significativa entre parto prematuro e ser nulípara e apresentar número baixo de consultas pré-natal. CONCLUSÕES: atenção especial deve ser dada às gestantes nulíparas e com número reduzido de consulta pré-natal submetidas ao tratamento de inibição de trabalho de parto prematuro, com a finalidade de prevenir esse evento.<br>OBJECTIVES: to identify preterm delivery prevalence in pregnant women submitted to preterm delivery inhibition treatment and to analyze associated factors. METHODS: cross sectional study with data collected from 163 pregnant women medical files seen from 1995-2000 at the University Hospital of the University of São Paulo, Brazil. The dependent variable was preterm delivery and the independent ones were: age, education, job, parity, companion, smoking, prior urinary infection, number of prenatal medical visits and birth interval. Analysis was performed through association by the Chi-square test and univariate and multiple logistic regression models. RESULTS: 66.3% of the women had preterm deliveries and in 22.7% of the cases, delivery occurred before 34 weeks. There was a statistically significant association between preterm birth and no partner, nulliparity and a low number of prenatal visits. CONCLUSIONS: special attention should be given to nulliparous pregnant women with reduced numbers of prenatal medical visits submitted to preterm delivery inhibition treatment with the objective of preventing premature births

New designs for MRI contrast agents

New designs for Magnetic Resonance Imaging contrast agents are presented. Essentially, they all are host-guest inclusion complexes between γ-cyclodextrins and polyazamacrocycles of gadolinium (III) ion. Substitutions have been made to the host to optimise the host-guest association. Molecular mechanics calculations have been performed, using the UFF force field for metals, to decide on the suitability of the substitutions, and to evaluate the host-guest energies of association. Interesting general conclusions have been obtained, concerning the improvement of Magnetic Resonance Imaging contrast agents; namely, a set of rational methodologies have been deduced to improve the association between the gadolinium (III) chelates and the cyclodextrins, and their efficiency is demonstrated with a large set of substituted complexes, opening new doors to increase the diagnostic capabilities of Magnetic Resonance Imaging