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We explore the feasibility of using FOS and JUN gene expression and ATR-FTIR for diagnosis of thyroid cancer. For the study, 38 samples (6 non-neoplastic (NN), 10 papillary thyroid carcinoma (PTC), 7 follicular thyroid carcinoma (FTC), and 15 benign tumors (BT) were subjected to RNA extraction followed by quantitative real time PCR (qRT-PCR) and 30 samples (5 NN, 9 PTC, 5 FTC, and 11 benign) were used for Attenuated Total Reflectance – Fourier Transform Infrared (ATR-FTIR) followed by multivariate analysis. We found FOS and JUN expression in malignant tumor samples to be significantly lower than NN and benign. ATR-FTIR after multivariate analysis could identify the difficult to diagnose PTC with 93% efficiency. Overall, results suggest the diagnostic potential of molecular biology techniques combined with ATR-FTIR spectroscopy in differentiated thyroid carcinomas (PTC and FTC) and benign tumors.

Differential sensitivities to the cell wall stress caused by Congo red (CR) have been observed in many fungal species. In this study, the tolerances and sensitivities to CR was studied with an assorted collection of fungal species from three phylogenetic classes: Sordariomycetes, Dothideomycetes, and Eurotiomycetes, three orders, and eight families. These grouped into different ecological niches, such as insect pathogens, plant pathogens, saprotrophs, and mycoparasitics. The saprotroph Aspergillus niger and the mycoparasite Trichoderma atroviride stood out as the most resistant species to cell wall stress caused by CR, followed by the plant pathogenic fungi, a mycoparasite, and other saprotrophs. The insect pathogens had low tolerance to CR. The insect pathogens Metarhizium acridum and Cordyceps fumosorosea were the most sensitive to CR. In conclusion, Congo red tolerance may reflect ecological niche, accordingly, the tolerances of the fungal species to Congo red were closely aligned with their ecology.

The effects of the visible light wavelengths on germination, mycelial radial growth, and conidial production of the plant pathogens Colletotrichum acutatum and Fusarium fujikuroi were studied. Both fungi were grown on potato dextrose agar medium (PDA) in the dark (control) or on PDA under continuous white, blue, green or red light. In addition, the conidia from each treatment were exposed to UV radiation. The germination and growth of both plant pathogenic fungi were not affected by any of the treatments. C. acutatum produced more conidia when the fungus grew under white and red light. F. fujikuroi produced more conidia in the dark. The tolerances to UV radiation of conidia produced on different light and dark treatments differed for both C. acutatum and F. fujikuroi. Conidia of C. acutatum were at least 30% more tolerant to UV radiation when they were produced under white light than under blue and green light and at least 20% more tolerant than conidia produced in the dark. Conidia of C. acutatum produced under red light were the least tolerant. Conidia of F. fujikuroi produced under white and blue light were at least 30% more UV tolerant than conidia produced in the dark, green, and red light. In conclusion, no differences were found for germination and growth for both fungi under different light regimes and dark; however, significant differences occurred both in production and UV radiation of conidia.

Alternative therapies against pathogens are under intense investigation because of their increasing resistance to antibiotics. Photodynamic therapy (PDT) is one such alternative that has shown promising results. However, for the widespread use of PDT, it is essential to decipher underlying mechanisms, so as to improve PDT's therapeutic applications. Because of this, we have studied biochemical changes in pathogen Pseudomonas aeruginosa, a medically important bacteria that has developed antibiotic resistance, after PDT with curcumin photosensitizer. Results show a drastic decrease in α-helix protein and increased disordered and β-sheet secondary structure proteins in P. Aeruginosa post-PDT compared to control. Interestingly, these biochemical changes differ from PDT of pathogens Leishmania braziliensis and Leishmania major with photosensitizer methylene blue. This observation underlines the need for extensive studies on PDT of different pathogens to understand mechanisms of action and develop better PDT strategies.

This study aims to explore biochemical changes in saliva during cardiorespiratory exercise using attenuated-total-reflectance-Fourier-transform-infrared-spectroscopy (ATR-FTIR). Saliva and blood samples were obtained from six athletes at rest, and after running at speeds of 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, and 20 kilometers-per-hour (km/h) on a treadmill (maximal stress test). Saliva ATR-FTIR spectra were analyzed using deconvolution and multivariate analysis. Area-under-the-curve calculations suggest differential changes in glucose, lactate, protein, lipids, carbohydrate and phosphate content in saliva during the test. Increases in glucose and lactate levels with increasing speeds were verified by simultaneous measurement of blood glucose and lactate levels using standard equipment (Roche®). Multivariate principal-component-analysis (PCA) showed discrete clusters for low (rest-14 km/h) and high (15 - 20 km/h) speeds, and PCA-linear-discriminant-analysis showed 100% classification of 18 - 20 km/h as high speed. Overall, results suggest the possibility of using this non-invasive saliva-based ATR-FTIR method for biochemical assessment during sports exercise and stress tests.

Light is an important signal for fungi in the environment and induces many genes with roles in stress and virulence responses. Conidia of the entomopathogenic fungi Aschersonia aleyrodis, Beauveria bassiana, Cordyceps fumosorosea, Lecanicillium aphanocladii, Metarhizium anisopliae, Metarhizium brunneum, Metarhizium robertsii, Simplicillium lanosoniveum, Tolypocladium cylindrosporum, and Tolypocladium inflatum were produced on potato dextrose agar (PDA) medium under continuous white light, on PDA medium in the dark, or under nutritional stress (= Czapek medium without sucrose = MM) in the dark. The conidial tolerance of these species produced under these different conditions were evaluated in relation to heat stress, oxidative stress (menadione), osmotic stress (KCl), UV radiation, and genotoxic stress caused by 4-nitroquinoline 1-oxide (4-NQO). Several fungal species demonstrated greater stress tolerance when conidia were produced under white light than in the dark; for instance white light induced higher tolerance of A. aleyrodis to KCl and 4-NQO; B. bassiana to KCl and 4-NQO; C. fumosorosea to UV radiation; M. anisopliae to heat and menadione; M. brunneum to menadione, KCl, UV radiation, and 4-NQO; M. robertsii to heat, menadione, KCl, and UV radiation; and T. cylindrosporum to menadione and KCl. However, conidia of L. aphanocladii, S. lanosoniveum, and T. inflatum produced under white light exhibited similar tolerance as conidia produced in the dark. When conidia were produced on MM, a much stronger stress tolerance was found for B. bassiana to menadione, KCl, UV radiation, and 4-NQO; C. fumosorosea to KCl and 4-NQO; Metarhizium species to heat, menadione, KCl, and UV radiation; T. cylindrosporum to menadione and UV radiation; and T. inflatum to heat and UV radiation. Again, conidia of L. aphanocladii and S. lanosoniveum produced on MM had similar tolerance to conidia produced on PDA medium in the dark. Therefore, white light is an important factor that induces higher stress tolerance in some insect-pathogenic fungi, but growth in nutritional stress always provides in conidia with stronger stress tolerance than conidia produced under white light.

Saliva has garnered a lot of interest as a non-invasive, easy to collect, and biochemical rich sample for attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR) based disease diagnosis. Although a large number of studies have explored its potential, the preparation methods used differ greatly. For large scale clinical studies to aid translation into clinics, the collection/processing methodology needs to be standardized. Therefore, in this study, we explored different saliva collection (spitting, method A/cotton soaking, method B) and processing protocols (unprepared, TS; supernatant from the centrifugation, CS; and drying, C) to find which gives the best ATR-FTIR signals. Analysis showed highest proteins, carbohydrates, amino acids, and nucleic acid + proteins/lipids in BTS, BCS, ACS, and BC, respectively. Notably, only BC shows a 1377 cm-1 nucleic acid band that is also uniquely identified in multivariate analysis. We conclude that the collection-processing protocol should be based on a biochemical component that best gives a differential diagnosis.

Soil regulates plant productivity in terrestrial ecosystems and maintains the balance of biogeochemical cycles through biotransformations mediated by living organisms, which are responsible for 80 to 90% of these functions. Therefore, it is necessary to evaluate whether restoration/natural regeneration processes in land degraded areas may allow the soil to partially or fully recover its microbial functions reflecting thus, in the fertility of these soils and consequently in the regeneration of forests. The use of microbiological attributes combined with infrared spectroscopy (FTIR) offers many opportunities to understand temporal dynamics and spatial variability in the recovery of important ecosystems during forest regeneration stages.The present work aims to evaluate the evolution of microbial quality in soils under three Atlantic Forest areas at different stages of regeneration (R40 - advanced, R12 - intermediate and RP - early regeneration pasture area) located in São Paulo state, Brazil. We used as indicators of the soil microbial quality the number of colony-forming units (CFU) of total bacteria and fungi, spore density and root colonization by arbuscular mycorrhizal fungi (AMF). We also analyzed these soils by Fourier Transform Infrared Spectroscopy (FTIR-UATR). For each area, seven soil samples and plant roots were randomly collected at a depth of 0-20 cm at the end of the dry season (October 2019). In terms of dry soil, the CFU bacteria for each area was, respectively, 7.7, 4.6 and 3.2 x 105 CFU g-1; fungi, 1.2, 1.0 and 0.6 x 103 g-1, and AMF spore density, 39, 33 and 27 spores 50 ml-1. On average, AMF root colonization was 26 (R40), 25 (R12) and 21% (PR). For the FTIR spectrum, the major bands and their assignments were identified as a 3.370 cm-1 wide band assigned to the O-H groupings; a peak at 1.635 cm-1 attributed to aromatic C=C vibration, with contribution of C=O of the COO- and a peak at 1.072 cm-1 attributed to the carbohydrate C-O bond. No difference was attributed to the composition of the main functional groups (O-H, C=O, COO- and C-O) between the soils from R40 and R12, but this difference was more evident when compared to the RP area. The microbiological results show good similarity between the tree areas in terms of spores, fungi and root colonization. However, in terms of bacteria, there is a more pronounced difference between the recent (RP) and the older regeneration areas (R12 and RP). Similar pattern was pointed by the FTIR results. Considering pasture as a strongly degrading area, these results are interesting since they show the differences in the soil quality between the three areas is not highly pronounced. They also show that in twelve years of regeneration, in many aspects’ soils become similar to the area with forty years regeneration. Given these results, a further investigation on soil physics of these areas is being developed to relate soil regeneration processes and soil physical properties such as porosity, density and water retention capacity, all of them important to the maintenance of vegetation and ecosystem services of water and climate regulation.

Survival of entomopathogenic fungi under solar ultraviolet (UV) radiation is paramount to the success of biological control of insect pests and disease vectors. The mutagenic compound 4-nitroquinoline 1-oxide (4-NQO) is often used to mimic the biological effects of UV radiation on organisms. Therefore, we asked whether tolerance to 4-NQO could predict tolerance to UV radiation in thirty isolates of entomopathogenic fungi and one isolate of a xerophilic fungus. A dendrogram obtained from cluster analyses based on the 50 and 90 % inhibitory concentrations (IC50 and IC90, respectively) divided the fungal isolates into six clusters numbered consecutively based on their tolerance to 4-NQO. Cluster 6 contained species with highest tolerance to 4-NQO (IC50 > 4.7 μM), including Mariannaea pruinosa, Lecanicillium aphanocladii, and Torrubiella homopterorum. Cluster 1 contained species least tolerant to 4-NQO (IC50

The low survival of insect-pathogenic fungi when used for insect control in agriculture is mainly due to the deleterious effects of ultraviolet radiation and heat from solar irradiation. In this study, conidia of 15 species of entomopathogenic fungi were exposed to simulated full-spectrum solar radiation emitted by a Xenon Test Chamber Q-SUN XE-3-HC 340S (Q-LAB® Corporation, Westlake, OH, USA), which very closely simulates full-spectrum solar radiation. A dendrogram obtained from cluster analyses, based on lethal time 50 % and 90 % calculated by Probit analyses, separated the fungi into three clusters: cluster 3 contains species with highest tolerance to simulated full-spectrum solar radiation, included Metarhizium acridum, Cladosporium herbarum, and Trichothecium roseum with LT50 > 200 min irradiation. Cluster 2 contains eight species with moderate UV tolerance: Aschersonia aleyrodis, Isaria fumosorosea, Mariannaea pruinosa, Metarhizium anisopliae, Metarhizium brunneum, Metarhizium robertsii, Simplicillium lanosoniveum, and Torrubiella homopterorum with LT50 between 120 and 150 min irradiation. The four species in cluster 1 had the lowest UV tolerance: Lecanicillium aphanocladii, Beauveria bassiana, Tolypocladium cylindrosporum, and Tolypocladium inflatum with LT50

O câncer de tireoide é a neoplasia mais comum do sistema endócrino, apresentando incidência crescente nos últimos anos. O diagnóstico é realizado principalmente pela associação de dois métodos: a ultrassonografia e a punção aspirativa por agulha fina (PAAF); porém ambos apresentam uma elevada taxa de resultados indeterminados. Deste modo, é necessária a busca de métodos diagnósticos alternativos para a obtenção de resultados mais precisos e confiáveis. A biologia molecular é uma área que se destaca nesse segmento de pesquisa, buscando compreender a biologia tumoral por meio da avaliação das alterações de expressão gênica. A técnica de PCR quantitativa em tempo real (RT-qPCR) é um método rápido e eficiente de detecção e quantificação de expressão gênica, apresentando alta sensibilidade e especificidade, e sendo considerada como uma ferramenta útil no diagnóstico de vários tipos de câncer. Neste estudo, amostras de carcinomas foliculares de tireoide, carcinomas papilíferos de tireoide, bócio adenomatoso e amostras de tecido normal da glândula foram obtidas com o objetivo de detectar marcadores moleculares diagnósticos por meio da avaliação da expressão dos genes TERT, CITED1 e SLC5A5 pela técnica de RT-qPCR, detectados com expressão aumentada nestas lesões, respectivamente. A expressão diferencial significativa foi detectada somente para o gene CITED1 na comparação das amostras de carcinoma papilífero de tireoide com bócio e tecidos normais, com aumento de expressão deste gene nas amostras de carcinoma papilifero. Os resultados obtidos sugerem o gene CITED1 como um potencial marcador diagnóstico em carcinoma papilífero de tireoide.

Background The increase in the incidence of Cervical Cancer in the female population worldwide has been an issue that deserves further attention from the scientific community. Several studies have already proven the relationship of its development with the molecular mechanisms that Human Papillomavirus (HPV) induces in cervical cells. The gene amplification provided by molecular biology techniques has been used as the gold standard diagnostic method of this virus because of its high specificity and sensitivity.However, the high investments associated with the acquisition of reagents, equipment and labor demonstrate the need for the development of more accessible techniques that present the same accuracy. FT-IR spectroscopy has been studied as an inexpensive and easily accessible technology that can provide the differentiation of malignant and benign cells. This study aimed to demonstrate the effectiveness and sensitivity of molecular analysis by PCR in relation to cytological analysis and to evaluate the sensitivity of FT-IR spectroscopy in the diagnosis of HPV for cervical cancer prevention. Methods Cervical fluid samples obtained from 50 patients with absence of cellular lesion by cytological analysis were analyzed by molecular and spectroscopic analyzes. Oncotic colpocitology analysis was performed by the Papanicolaou staining, amplification of the L1 viral gene by PCR was performed using primers MY09 and MY11 and biochemical analysis of the fluids by FT-IR was performed using the Spectrum 400 system equipped with a microscope. Results Of the 50 patients without evident morphological alteration of the cells, seven were diagnosed by molecular analysis as positive for presence of HPV. Principal component analysis of spectroscopy was not able to separate the negative samples from the HPV positive samples and, therefore, did not present as an effective diagnostic technique. Conclusions We highlight the efficacy, sensitivity and specificity of molecular biology by PCR in the identification of the virus and we emphasize that more studies should be used for the application of FT-IR spectroscopy in the diagnosis of this infection and its application in the prevention of cervical cancer.

Osmotic stress induced by high solute concentration can prevent fungal metabolism and growth due to alterations in properties of the cytosol, changes in turgor, and the energy required to synthesize and retain compatible solutes. We used germination to quantify tolerance/sensitivity to the osmolyte KCl (0.1–4.5 M, in 0.1 M increments) for 71 strains (40 species) of ecologically diverse fungi. These include 11 saprotrophic species (17 strains, including two xerophilic species), five mycoparasitic species (five strains), six plant-pathogenic species (13 strains), and 19 entomopathogenic species (36 strains). A dendrogram obtained from cluster analyses, based on KCl inhibitory concentrations 50 % and 90 % calculated by Probit Analysis, revealed three groups of fungal isolates accordingly to their osmotolerance. The most-osmotolerant group (Group 3) contained the majority of saprotrophic fungi, and Aspergillus niger (F19) was the most tolerant. The highly xerophilic Aspergillus montevidense and Aspergillus pseudoglaucus were the second- and third-most tolerant species, respectively. All Aspergillus and Cladosporium species belonged to Group 3, followed by the entomopathogens Colletotrichum fioriniae, Simplicillium lanosoniveum, and Trichothecium roseum. Group 2 exhibited a moderate osmotolerance, and included plant-pathogens such as Colletotrichum and Fusarium, mycoparasites such as Clonostachys spp, some saprotrophs such as Mucor and Penicillium spp., and some entomopathogens such as Isaria, Lecanicillium, Mariannaea, Simplicillium, and Torrubiella. Group 1 contained the osmo-sensitive strains: the rest of the entomopathogens and the mycoparasitic Gliocladium and Trichoderma. Although stress tolerance did not correlate with their primary ecological niche, classification of these 71 fungal strains was more closely aligned with their ecology than with their phylogenetic relatedness. We discuss the implications for both microbial ecology and fungal taxonomy.

Fungi sense light and utilize it as a source of environmental information to prepare against many stressful conditions in nature. In this study, Metarhizium robertsii was grown on: 1) potato dextrose agar medium (PDA) in the dark (control); 2) under nutritive stress in the dark; and 3) PDA under continuous (A) white light; (B) blue light lower irradiance = LI; (C) blue light higher irradiance = HI; (D) green light; and (E) red light. Conidia produced under these treatments were tested against osmotic stress and UV radiation. In addition, a suite of genes usually involved in different stress responses were selected to study their expression patterns. Conidia produced under nutritive stress in the dark were the most tolerant to both osmotic stress and UV radiation, and the majority of their stress- and virulence-related genes were up-regulated. For osmotic stress tolerance, conidia produced under white, blue LI, and blue HI lights were the second most tolerant, followed by conidia produced under green light. Conidia produced under red light were the least tolerant to osmotic stress and less tolerant than conidia produced on PDA medium in the dark. For UV tolerance, conidia produced under blue light LI were the second most tolerant to UV radiation, followed by the UV tolerances of conidia produced under white light. Conidia produced under blue HI, green, and red lights were the least UV tolerant and less tolerant than conidia produced in the dark. The superoxide dismutases (sod1 and sod2), photolyases (6-4phr and CPDphr), trehalose-phosphate synthase (tps), and protease (pr1) genes were highly up-regulated under white light condition, suggesting a potential role of these proteins in stress protection as well as virulence after fungal exposure to visible spectrum components.

Background Approximately 70% of cervical carcinoma cases show the presence of high-risk Human Papilloma Virus (HPV), especially HPV-16 and HPV-18, and can be used to stratify high risk patients from low risk and healthy. Currently, molecular biology techniques such as polymerase chain reaction (PCR) are used to identify the presence of virus in patient samples. While the methodology is highly sensitive, it is labor intensive and time-consuming. Alternative techniques, such as vibrational spectroscopy, has been suggested as a possible rapid alternative. Therefore, in this study, we evaluate the efficiency of cervical fluid Fourier Transform Infrared spectroscopy (FTIR) in patient risk stratification informed by PCR. Methods Cervical fluid samples (n = 91) were obtained from patients who have undergone routine Papanicolaou (Pap) test. Viral genome was identified and classified as high/low-risk by PCR-Restriction Fragment Length Polymorphism (PCR-RFLP). FTIR spectra were acquired from samples identified by PCR-RFLP as No-HPV (n = 10), high-risk HPV (n = 7), and low-risk HPV (n = 7). Results Of the 91 samples, was detected the viral genome by PCR in 36 samples. Of these 36 samples, nine samples were identified to contain high-risk HPV (HR-HPV) and nine samples were found to have low-risk HPV (LR-HPV). The FTIR spectra acquired from No-HPV, LR-HPV, and HR-HPV showed differences in 1069, 1437, 1555, 1647, 2840, 2919, and 3287 cm-1 bands. Principal Component Analysis (PCA) showed distinct clusters for No-HPV and HR-HPV and No-HPV and LR-HPV, but there was significant overlap in the clusters of HR-HPV and LR-HPV. PCA-Linear Discriminant Analysis (PC-LDA) after Leave One Out Cross Validation (LOOCV) classified No-HPV from HR-HPV and No-HPV from LR-HPV with 100% efficiency in the 1400-1800 cm-1 spectral range. LOOCV classifications for LR-HPV and HR-HPV from each other were 71 and 75%, respectively, in the 2800-3400 cm-1 spectral range. Conclusions The results highlight the high sensitivity of PCR-RFLP in HPV identification and show that FTIR can classify samples identified as healthy, low, and high-risk samples by PCR-RFLP. General significance We show the possibility of using FTIR for initial cervical cancer risk stratification followed by detailed PCR-RFLP investigations for suspect cases., Highlights • Molecular biology showed high sensitivity and specificity in HPV detection compared with cytological analysis. • PCR-RFLP technique identify high-risk variants of HPV can significantly assist in the prevention of cervical cancer. • PC-LDA and LOOCV classified normal from high-risk HPV and normal from low-risk HPV with 100% efficiency. • FTIR can be used for initial cervical cancer risk stratification followed by more detailed investigations by PCR-RFLP.

Thyroid cancer has become in recent years the most common endocrine malignancy. Among its different types, papillary thyroid carcinoma (PTC) has the highest incidence. PTC is slow growing, but shows a high rate of lymph node metastasis. Tissue biochemical characterization and identification of molecular markers can facilitate stratification of patients into those requiring surgical assessment of lymph nodes and patients for whom this surgical procedure is unnecessary; thus, leading to a more accurate prognosis. To this end, the study aimed to predict lymph node metastasis by Attenuated Total Reflectance - Fourier transform infrared (ATR-FTIR) spectroscopy of primary PTC tumors. Another objective of the study was to determine whether CCNA1, CDKN1C, FOS, HSPA5, JUN, KSR1, MAP2K6, MAPK8IP2 and SFN gene expression in primary PTC tumors could be used as predictive markers of lymph node metastasis. Three PTC with lymph node involvement (PTC+), six PTC without lymph node involvement (PTC-), and five normal (N) thyroid tissues were used for FTIR spectroscopy analysis; while 18 PTC+, 17 PTC-, and 6 N samples were used for molecular analysis by real-time quantitative PCR (RT-qPCR). FTIR spectral analysis revealed changes in phosphate groups possibly associated with nucleic acid (1236 cm−1), and protein/lipids (1452, 2924, 3821 cm−1) in PTC + compared to PTC-, and multivariate analysis could distinguish the two groups. Molecular analysis showed significant increase in CDKN1C gene expression in PTC + compared to PTC-. Being a cell growth regulator, increased CDKN1C provides some supporting evidence to the FTIR spectroscopy based finding of increased nucleic acids in PTC+. Thus, the study suggests the possibility of using FTIR spectroscopy and CDKN1C expression for predicting metastasis using primary tumor alone.

The low survival of insect-pathogenic fungi when used for insect control in agriculture is mainly due to the deleterious effects of ultraviolet radiation and heat from solar irradiation. In this study, conidia of 15 species of entomopathogenic fungi were exposed to simulated full-spectrum solar radiation emitted by a Xenon Test Chamber Q-SUN XE-3-HC 340S (Q-LAB

Microorganisms are essential to the functionality of the soil, particularly in organic matter decomposition and nutrient cycling, which regulate plant productivity and shape the soil structure. However, biotic and abiotic stresses greatly disrupt soil fungal communities and, thereby, disturb the ecosystem. This study quantified seasonal tolerances to UV-B radiation and heat of fungal communities, which could be cultured, found in soil from two native Atlantic forest fragments called F1 and F2, five reforested areas (RA) planted in 1994, 1997, 2004, 2007, and 2009 with native species of the Atlantic forest, and one sand mining degraded soil (SMDS). The cold activity of the soil fungal communities (FC) from the eight different areas was also studied. Higher tolerance to UV-B radiation and heat was found in the FC from the SMDS and the 2009RA, where the incidence of heat and UV radiation from sun was more intense, which caused selection for fungal taxa that were more UV-B and heat tolerant in those areas. Conversely, the FC from the native forests and older reforested sites were very susceptible to heat and UV-B radiation. The cold activity of the soil FC from different areas of the study showed an erratic pattern of responses among the sampling sites. Little difference in tolerance to UV-B radiation and heat was found among the FC of soil samples collected in different seasons; in general soil FC collected in winter were less tolerant to UV-B radiation, but not for heat. In conclusion, FC from SMDS soil that receive intense heat and UV radiation, as well as with low nutrient availability, were more tolerant to both UV-B radiation and heat.

The availability of phosphorus (P) for the growth of plants often depends on the solubilisation of inorganic phosphates (P fractions) in the soil. The aim of this study was to investigate soil P fractions in terms of availability and soil characteristics of mangrove soil compared with the Atlantic forest and restinga soils that occur at Cardoso Island, Brazil. Soil samples were collected during summer at depths of 0–2, 2–5 and 5–10 cm. Except for Ca-P, the quantity of P fractions in the soils decreased in the order: Atlantic forest > mangrove > restinga. Principal components analysis showed that treatments were clustered into two groups based on ecosystem proprieties; P in mangrove soil was associated with pH, moisture and salinity, and P in Atlantic forest soil with soil organic matter (SOM). The P in restinga soil was not associated with any variable. Among fractions, iron (Fe)-P was dominant, followed by calcium (Ca)-P and aluminium (Al)-P. The most recalcitrant P fractions, reductant Fe-P, occluded (o) Fe-P and oAl-P were detected in minor amounts. Soluble (sol)-P was detected only in the Atlantic forest soil. Soil P fractions varied little with depth in the mangrove and restinga soils. The P fractions from Atlantic forest soil were found at depths of 0–2 cm (Fe-P, Ca-P) and 2–5 cm (sol-P, Al-P, Fe-P, oAl-P and oFe-P). Positive correlation was obtained for all P fractions with moisture (except sol-P and Fe-P) and SOM (except Ca-P) contents and negative correlation with soil pH (except Ca-P) and salinity (except Fe-P and Al-P). Quantities and qualities of the P fractions varied among the studied ecosystems, influenced by the parent material and physico-chemical characteristics of the soil and vegetation.

Sugarcane culture is replanted after five–eight successive harvests and intensely fertilised and mechanised. The influence on bacteria (total, nitrifying, denitrifying), fungi, microbial biomass-C, and dynamic processes (respiratory activity, N mineralisation, potential nitrification, P-solubilising activity) and enzymatic activities (dehydrogenase, urease, phosphatase) was studied for six successive harvests of the crop. The straw of the second and third harvest was burned. Soil microbial counts and activities were reduced after successive harvests. Fungi counts, N mineralisation, potential nitrification, and the P-solubilising, urease, and phosphatase activities decreased gradually from the first harvest to the third, increased again after the fourth, and then decreased again. Total, nitrifying, and denitrifying bacteria and fungi counts decreased, on average, 55, 22, 17, and 77%, respectively, in the sixth harvest in relation to the first. Reductions also occurred in microbial biomass-C (43%), respiratory activity (39%), N mineralisation (35%), potential nitrification (40%), and P-solubilising activity (35%). Reductions were observed in dehydrogenase (58%) and urease (36%) activities, but not in phosphatase activity. Successive sugarcane harvests may significantly influence microbial populations and activities, with harmful consequences to the C, N, and P cycles, and may decrease crop productivity.