A home-based lifestyle intervention program reduces the tumorigenic potential of triple-negative breast cancer cells.

Translational research for the evaluation of physical activity habits and lifestyle modifications based on nutrition and exercise has recently gained attention. In this study, we evaluated the effects of serum samples obtained before and after a 12-week home-based lifestyle intervention based on nutrition and exercise in breast cancer survivors in terms of modulation of the tumorigenic potential of breast cancer cells. The home-based lifestyle intervention proposed in this work consisted of educational counselling on exercise and nutritional behaviors and in 12 weeks of structured home-based exercise. Triple-negative breast cancer cell line MDA-MB-231 was cultured in semi-solid medium (3D culture) with sera collected before (PRE) and after (POST) the lifestyle intervention program. Spheroid formation was evaluated by counting cell colonies after 3 weeks of incubation. Results show a slight but significant reduction of spheroid formation induced by serum collected POST in comparison to those obtained PRE. Moreover, statistical analyses aimed to find physiologic and metabolic parameters associated with 3D cell proliferation revealed the proliferative inducer IGF-1 as the only predictor of cell tumorigenic potential. These results highlight the importance of lifestyle changes for cancer progression control in a tertiary prevention context. Translational research could offer a useful tool to identify metabolic and physiological changes induced by exercise and nutritional behaviors associated with cancer progression and recurrence risk.

Effect of a lifestyle intervention program's on breast cancer survivors' cardiometabolic health: Two-year follow-up.

The purpose of this study is to assess the cardiometabolic responses of a lifestyle intervention (LI) conducted at home among breast cancer (BC) survivors during the two years of COVID-19 pandemic. A 3-month LI focused on diet and exercise was performed on thirty BC survivors (women; stages 0-II; non-metastatic; aged 53.6 ± 7.6 years; non-physically active) with a risk factor related to metabolic/endocrine diseases. Anthropometrics, cardiorespiratory fitness (V˙O2max), physical activity level (PAL), adherence to the Mediterranean diet (MeDiet modified questionnaire), and several biomarkers (i.e., glycemia, insulin, insulin resistance [HOMA-IR] index, triglycerides, high- [HDL] and low- [LDL] density lipoproteins, total cholesterol, progesterone, testosterone, and hs-troponin) were evaluated before and 3-, 6-, 12-, and 24-month after the LI. Beneficial effects of the LI were observed on several variables (i.e., body mass index, waist circumference, MeDiet, PAL, V˙ O2max, glycemia, insulin, HOMA-IR index, LDL, total cholesterol, triglycerides, testosterone) after 3-month. The significant effect on Mediterranean diet adherence and V˙ O2max persisted up to the 24-month follow-up. Decreases in HOMA-IR index and triglycerides were observed up to 12-month, however did not persist afterward. This study provides evidence on the positive association between LI and cardiometabolic health in BC survivors.

Movement and health beyond care, MoviS: study protocol for a randomized clinical trial on nutrition and exercise educational programs for breast cancer survivors.

BACKGROUND: Breast cancer (BC) is the most common invasive cancer in women, and exercise can significantly improve the outcomes of BC survivors. MoviS (Movement and Health Beyond Care) is a randomized controlled trial aimed to evaluate the potential health benefits of exercise and proper nutritional habits. This study aims to assess the efficacy of aerobic exercise training in improving quality of life (QoL) and health-related factors in high-risk BC. METHODS: One hundred seventy-two BC survivor women, aged 30-70 years, non-metastatic, stage 0-III, non-physically active, 6-12 months post-surgery, and post chemo- or radiotherapy, will be recruited in this study. Women will be randomly allocated to the intervention arm (lifestyle recommendations and MoviS Training) or control arm (lifestyle recommendations). The MoviS training consists of 12 weeks of aerobic exercise training (2 days/week of supervised and 1 day/week of unsupervised exercise) with a progressive increase in exercise intensity (40-70% of heart rate reserve) and duration (20-60 min). Both arms will receive counseling on healthy lifestyle habits (nutrition and exercise) based on the World Cancer Research Fund International (WCRF) 2018 guidelines. The primary outcome is the improvement of the QoL. The secondary outcomes are improvement of health-related parameters such as Mediterranean diet adherence, physical activity level, flexibility, muscular fitness, fatigue, cardiorespiratory fitness (estimated maximal oxygen uptake), echocardiographic parameters, heart rate variability (average of the standard deviations of all 5 min normal to normal intervals (ASDNN/5 min) and 24 h very low and low frequency), and metabolic, endocrine, and inflammatory serum biomarkers (glycemia, insulin resistance, progesterone, testosterone, and high-sensitivity C-reactive protein). DISCUSSION: This trial aims to evaluate if supervised exercise may improve QoL and health-related factors of BC survivors with a high risk of recurrence. Findings from this project could provide knowledge improvement in the field of exercise oncology through the participation of a multidisciplinary team that will provide a coordinated program of cancer care to improve healthcare quality, improve prognosis, increase survival times and QoL, and reduce the risk of BC recurrence. TRIAL REGISTRATION: ClinicalTrials.gov  NCT04818359 . Retrospectively registered on March 26, 2021.

Defective IGF-1 prohormone N-glycosylation and reduced IGF-1 receptor signaling activation in congenital disorders of glycosylation.

The insulin-like growth factor-1 (IGF-1) signaling pathway is crucial for the regulation of growth and development. The correct processing of the IGF-1Ea prohormone (proIGF-1Ea) and the IGF-1 receptor (IGF-1R) peptide precursor requires proper N-glycosylation. Deficiencies of N-linked glycosylation lead to a clinically heterogeneous group of inherited diseases called Congenital Disorders of Glycosylation (CDG). The impact of N-glycosylation defects on IGF-1/IGF-1R signaling components is largely unknown. In this study, using dermal fibroblasts from patients with different CDG [PMM2-CDG (n = 7); ALG3-CDG (n = 2); ALG8-CDG (n = 1); GMPPB-CDG (n = 1)], we analyzed the glycosylation pattern of the proIGF-1Ea, IGF-1 secretion efficiency and IGF-1R signaling activity. ALG3-CDG, ALG8-CDG, GMPPB-CDG and some PMM2-CDG fibroblasts showed hypoglycosylation of the proIGF-1Ea and lower IGF-1 secretion when compared with control (CTR). Lower IGF-1 serum concentration was observed in ALG3-CDG, ALG8-CDG and in some patients with PMM2-CDG, supporting our in vitro data. Furthermore, reduced IGF-1R expression level was observed in ALG3-CDG, ALG8-CDG and in some PMM2-CDG fibroblasts. IGF-1-induced IGF-1R activation was lower in most PMM2-CDG fibroblasts and was associated with decreased ERK1/2 phosphorylation as compared to CTR. In general, CDG fibroblasts showed a slight upregulation of Endoplasmic Reticulum (ER) stress genes compared with CTR, uncovering mild ER stress in CDG cells. ER-stress-related gene expression negatively correlated with fibroblasts IGF-1 secretion. This study provides new evidence of a direct link between N-glycosylation defects found in CDG and the impairment of IGF-1/IGF-1R signaling components. Further studies are warranted to determine the clinical consequences of reduced systemic IGF-1 availability and local activity in patients with CDG.

Altered muscle mitochondrial, inflammatory and trophic markers, and reduced exercise training adaptations in type 1 diabetes.

Growing evidence of impaired skeletal muscle health in people with type 1 diabetes points toward the presence of a mild myopathy in this population. However, this myopathic condition is not yet well characterised and often overlooked, even though it might affect the whole-body glucose homeostasis and the development of comorbidities. This study aimed to compare skeletal muscle adaptations and changes in glycaemic control after 12 weeks of combined resistance and aerobic (COMB) training between people with type 1 diabetes and healthy controls, and to determine whether the impaired muscle health in type 1 diabetes can affect the exercise-induced adaptations. The COMB training intervention increased aerobic capacity and muscle strength in both healthy and type 1 diabetes sedentary participants, although these improvements were higher in the control group. Better glucose control, reduced glycaemic fluctuations and fewer hypoglycaemic events were recorded at post- compared to pre-intervention in type 1 diabetes. Analysis of muscle biopsies showed an alteration of muscle markers of mitochondrial functions, inflammation, ageing and growth/atrophy compared to the control group. These muscular molecular differences were only partially modified by the COMB training and might explain the reduced exercise adaptation observed in type 1 diabetes. In brief, type 1 diabetes impairs many aspects of skeletal muscle health and might affect the exercise-induced adaptations. Defining the magnitude of diabetic myopathy and the effect of exercise, including longer duration of the intervention, will drive the development of strategies to maximise muscle health in the type 1 diabetes population. KEY POINTS: Type 1 diabetes negatively affects skeletal muscle health; however, the effect of structured exercise training on markers of mitochondrial function, inflammation and regeneration is not known. Even though participants with type 1 diabetes and healthy control were comparable for cardiorespiratory fitness ( V̇O2max${\dot{V}_{{{\rm{O}}_{\rm{2}}}{\rm{max}}}}$ ) and muscle strength at baseline, molecular markers related to muscle health were decreased in type 1 diabetes. After training, both groups increased V̇O2max${\dot{V}_{{{\rm{O}}_{\rm{2}}}{\rm{max}}}}$ and muscle strength; however, a larger improvement was achieved by the control group. The training intervention decreased glucose fluctuations and occurrence of hypoglycaemic events in type 1 diabetes, while signs of mild myopathy found in the muscle of participants with type 1 diabetes only partially improved after training Improving muscle health by specific exercise protocols is of considerable clinical interest in therapeutic strategies for improving type 1 diabetes management and preventing or delaying long-term complications.

Interventions on Gut Microbiota for Healthy Aging.

In recent years, the improvement in health and social conditions has led to an increase in the average lifespan. Since aging is the most important risk factor for the majority of chronic human diseases, the development of therapies and intervention to stop, lessen or even reverse various age-related morbidities is an important target to ameliorate the quality of life of the elderly. The gut microbiota, that is, the complex ecosystem of microorganisms living in the gastrointestinal tract, plays an important role, not yet fully understood, in maintaining the host's health and homeostasis, influencing metabolic, oxidative and cognitive status; for this reason, it is also named "the forgotten endocrine organ" or "the second brain". On the other hand, the gut microbiota diversity and richness are affected by unmodifiable factors, such as aging and sex, and modifiable ones, such as diet, pharmacological therapies and lifestyle. In this review, we discuss the changes, mostly disadvantageous, for human health, induced by aging, in microbiota composition and the effects of dietary intervention, of supplementation with probiotics, prebiotics, synbiotics, psychobiotics and antioxidants and of physical exercise. The development of an integrated strategy to implement microbiota health will help in the goal of healthy aging.

Effects of a Home-Based Lifestyle Intervention Program on Cardiometabolic Health in Breast Cancer Survivors during the COVID-19 Lockdown.

This study aimed to evaluate the cardiometabolic effects of a home-based lifestyle intervention (LI) in breast cancer survivors (BCSs) during the COVID-19 lockdown. In total, 30 BCSs (women; stages 0-II; non-metastatic; aged 53.5 ± 7.6 years; non-physically active; normal left ventricular systolic function) with a risk factor for recurrence underwent a 3-month LI based on nutrition and exercise. Anthropometrics, Mediterranean diet adherence, physical activity level (PAL), cardiorespiratory fitness (VO2max), echocardiographic parameters, heart rate variability (average standard deviation of NN intervals (ASDNN/5 min) and 24 h very- (24 hVLF) and low-frequency (24 hLF)), and metabolic, endocrine, and inflammatory serum biomarkers (glycemia, insulin resistance, progesterone, testosterone, and high-sensitivity C-reactive protein (hs-CRP)) were evaluated before (T0) and after (T1) the LI. After the LI, there were improvements in: body mass index (kg/m2: T0 = 26.0 ± 5.0, T1 = 25.5 ± 4.7; p = 0.035); diet (Mediet score: T0 = 6.9 ± 2.3, T1 = 8.8 ± 2.2; p < 0.001); PAL (MET-min/week: T0 = 647 ± 547, T1 = 1043 ± 564; p < 0.001); VO2max (mL·min-1·kg-1: T0 = 30.5 ± 5.8, T1 = 33.4 ± 6.8; p < 0.001); signs of diastolic dysfunction (participants: T0 = 15, T1 = 10; p = 0.007); AS-DNN/5 min (ms: T0 = 50.6 ± 14.4, T1 = 55.3 ± 16.7; p = 0.032); 24 hLF (ms2: T0 = 589 ± 391, T1 = 732 ± 542; p = 0.014); glycemia (mg/dL: T0 = 100.8 ± 11.4, T1 = 91.7 ± 11.0; p < 0.001); insulin resistance (HOMA-IR score: T0 = 2.07 ± 1.54, T1 = 1.53 ± 1.11; p = 0.005); testosterone (ng/mL: T0 = 0.34 ± 0.27, T1 = 0.24 ± 0.20; p = 0.003); hs-CRP (mg/L: T0 = 2.18 ± 2.14, T1 = 1.75 ± 1.74; p = 0.027). The other parameters did not change. Despite the home-confinement, LI based on exercise and nutrition improved cardiometabolic health in BCSs.

Effects of acute aerobic, resistance and combined exercises on 24-h glucose variability and skeletal muscle signalling responses in type 1 diabetics.

PURPOSE: To compare the effect of high-intensity aerobic (AER), resistance (RES), and combined (COMB: RES + AER) exercise, on interstitial glucose (IG) variability and skeletal muscle signalling pathways in type 1 diabetes (T1D). METHODS: T1D participants (6 M/6F) wore a flash glucose monitoring system in four randomized sessions: one control (CONT), and one AER, RES and COMB (40 min each). Mean amplitude of glycemic excursions (MAGE), standard deviation (SD) and coefficient variation (CV) of IG were used to compare the 24 h post-exercise IG variability. Blood and muscle samples were collected to compare exercise-induced systemic and muscle signalling responses related to metabolic, growth and inflammatory adaptations. RESULTS: Both RES and COMB decreased the 24 h MAGE compared to CONT; additionally, COMB decreased the 24 h SD and CV. In the 6-12 h post-exercise, all exercise modalities reduced the IG CV while SD decreased only after COMB. Both AER and COMB stimulated the PGC-1α mRNA expression and promoted the splicing of IGF-1Ea variant, while Akt and p38MAPK phosphorylation increased only after RES and COMB. Additionally, COMB enhanced eEF2 activation and RES increased myogenin and MRF4 mRNA expression. Blood lactate and glycerol levels and muscle IL-6, TNF-α, and MCP-1 mRNAs increased after all exercise sessions, while serum CK and LDH level did not change. CONCLUSION: COMB is more effective in reducing IG fluctuations compared to single-mode AER or RES exercise. Moreover, COMB simultaneously activates muscle signalling pathways involved in substrate metabolism and anabolic adaptations, which can help to improve glycaemic control and maintain muscle health in T1D.

Phytochemical composition, antioxidant and antiproliferative activities and effects on nuclear DNA of ethanolic extract from an Italian mycelial isolate of Ganoderma lucidum.

ETHNOPHARMACOLOGICAL RELEVANCE: Ganoderma lucidum (Curtis) P. Karst. (also known as Linghzhi and Reishi) is the most appreciated and revered medicinal mushroom across many Asian countries, but its properties have also attracted interest in Western countries. Indeed, in the West, it is now commercially available as a dietary supplement in preparations mainly made from spores, fruiting bodies and mycelia. It is employed in both nutraceutical and pharmacological formulations either for its immuno-modulating anti-inflammatory properties or as an effective adjuvant therapy in the treatment of several chronic diseases as well as in cancer treatment. AIM OF THE STUDY: The aim of this investigation was to show the phytochemical composition and antioxidant and antiproliferative activities of an ethanolic extract from an Italian mycelial isolate of Ganoderma lucidum and to assess its effects on nuclear DNA. MATERIALS AND METHODS: LC/ESI-MS and tandem mass spectrometry MSMS were used to obtain structural identification of ethanolic G. lucidum extract constituents. Antioxidant activities were determined by the DPPH method, chelating effect on Fe2+ and lipoxygenase inhibition while cytotoxic activities using the MTT assay. Effects on nuclear DNA were evaluated using the DNA nicking assay in a cell-free system and the fast halo assay performed on oxidatively injured human U937 cells; apoptosis induction was investigated using the non-denaturing fast halo assay and DNA laddering detection. RESULTS: This extract was rich in several bioactive compounds, mainly phenolic and triterpenic acids. It showed antioxidant activity and protective effects in oxidatively injured DNA in cell-free analyses and antiproliferative, genotoxic, and proapoptotic effects in the cell model. CONCLUSIONS: Italian G. lucidum mycelium isolate appears to be a source of various natural compounds that may have applications as chemopreventive agents or functional foods.

The intrinsically disordered E-domains regulate the IGF-1 prohormones stability, subcellular localisation and secretion.

Insulin-like growth factor-1 (IGF-1) is synthesised as a prohormone (proIGF-1) requiring enzymatic activity to yield the mature IGF-1. Three proIGF-1s are encoded by alternatively spliced IGF-1 mRNAs: proIGF-1Ea, proIGF-1Eb and proIGF-1Ec. These proIGF-1s have a common IGF-1 mature sequence but different E-domains. The structure of the E-domains has not been resolved, and their molecular functions are still unclear. Here, we show that E-domains are Intrinsically Disordered Regions that have distinct regulatory functions on proIGF-1s production. In particular, we identified a highly conserved N-glycosylation site in the Ea-domain, which regulated intracellular proIGF-1Ea level preventing its proteasome-mediated degradation. The inhibition of N-glycosylation by tunicamycin or glucose starvation markedly reduced proIGF-1Ea and mature IGF-1 production. Interestingly, 2-deoxyglucose, a glucose and mannose analogue, increased proIGF-1Ea and mature IGF-1 levels, probably leading to an accumulation of an under-glycosylated proIGF-1Ea that was still stable and efficiently secreted. The proIGF-1Eb and proIGF-1Ec were devoid of N-glycosylation sites, and hence their production was unaffected by N-glycosylation inhibitors. Moreover, we demonstrated that alternative Eb- and Ec-domains controlled the subcellular localisation of proIGF-1s, leading to the nuclear accumulation of both proIGF-1Eb and proIGF-1Ec. Our results demonstrated that E-domains are regulatory elements that control IGF-1 production and secretion.

Sugar transporters in the black truffle Tuber melanosporum: from gene prediction to functional characterization.

In a natural forest ecosystem, ectomycorrhiza formation is a way for soil fungi to obtain carbohydrates from their host plants. However, our knowledge of sugar transporters in ectomycorrhizal ascomycetous fungi is limited. To bridge this gap we used data obtained from the sequenced genome of the ectomycorrhizal fungus Tuber melanosporum Vittad. to search for sugar transporters. Twenty-three potential hexose transporters were found, and three of them (Tmelhxt1, Tmel2281 and Tmel131), differentially expressed during the fungus life cycle, were investigated. The heterologous expression of Tmelhxt1 and Tmel2281 in an hxt-null Saccharomyces cerevisiae strain restores the growth in glucose and fructose. The functional characterization and expression profiles of Tmelhxt1 and Tmel2281 in the symbiotic phase suggest that they are high affinity hexose transporters at the plant-fungus interface. On the contrary, Tmel131 is preferentially expressed in the fruiting body and its inability to restore the S. cerevisiae mutant strain growth led us to hypothesize that it could be involved in the transport of alternative carbon sources important for a hypothetical saprophytic strategy for the complete maturation of the carpophore.

Biochemical characterization and antioxidant and antiproliferative activities of different Ganoderma collections.

The aim of this study was to conduct a molecular and biochemical characterization and to compare the antioxidant and antiproliferative activities of four Ganoderma isolates belonging to Ganoderma lucidum (Gl-4, Gl-5) and Ganoderma resinaceum (F-1, F-2) species. The molecular identification was performed by ITS and IGS sequence analyses and the biochemical characterization by enzymatic and proteomic approaches. The antioxidant activity of the ethanolic extracts was compared by three different methods and their flavonoid contents were also analyzed by high-performance liquid chromatography. The antiproliferative effect on U937 cells was determined by MTT assay. The studied mycelia differ both in the enzymatic activities and protein content. The highest content in total phenol and the highest antioxidant activity for DPPH free radical scavenging and chelating activity on Fe(2+) were observed with the Gl-4 isolate of G. lucidum. The presence of quercetin, rutin, myricetin, and morin as major flavonoids with effective antioxidant activity was detected. The ethanolic extracts from mycelia of G. lucidum isolates possess a substantial antiproliferative activity against U937 cells in contrast to G. resinaceum in which the antiproliferative effects were insignificant. This study provides a comparison between G. lucidum and G. resinaceum mycelial strains, and shows that G. resinaceum could be utilized to obtain several bioactive compounds.

Effect of 300 mT static and 50 Hz 0.1 mT extremely low frequency magnetic fields on Tuber borchii mycelium.

The present work aimed to investigate whether exposure to static magnetic field (SMF) and extremely low frequency magnetic field (ELF-MF) can induce biomolecular changes on Tuber borchii hyphal growth. Tuber borchii mycelium was exposed for 1 h for 3 consecutive days to a SMF of 300 mT or an ELF-MF of 0.1 mT 50 Hz. Gene expression and biochemical analyses were performed. In mycelia exposed to ELF-MF, some genes involved in hyphal growth, investigated using quantitative real-time polymerase chain reaction, were upregulated, and the activity of many glycolytic enzymes was increased. On the contrary, no differences were observed in gene expression after exposure to SMF treatment, and only the activities of glucose 6-phosphate dehydrogenase and hexokinase increased. The data herein presented suggest that the electromagnetic field can act as an environmental factor in promoting hyphal growth and can be used for applicative purposes, such as the set up of new in vitro cultivation techniques.

Hyphal and cytoskeleton polarization in Tuber melanosporum: a genomic and cellular analysis.

Filamentous polarized growth involves a series of events including polarization of the cytoskeleton to selected growth sites, and the transport of secretory vesicles containing the components required for growth. The availability of fungal genome sequences has recently led to the identification of a large number of proteins involved in these processes. We have explored the Tuber melanosporum genome sequence by searching for homologs of genes known to play crucial roles in the morphogenesis and cell polarity of yeasts and filamentous fungi. One hundred and forty-nine genes have been identified and functionally grouped according to the deduced amino acid sequences (44 genes involved in cell polarity/morphogenesis, 39 belonging to the actin cytoskeleton and 66 involved in membrane dynamics, septation and exocytosis). A detailed gene annotation has shown that most components of the cell polarity machinery, morphogenesis and cytoskeleton found in yeasts and filamentous fungi are conserved, although the degree of similarity varies from strong to weak. Microscopic analysis of quick-frozen truffle hyphae detected the characteristic subcellular components of the hyphal tip in septate filamentous fungi, while transcript profiles revealed a moderately variable pattern during the biological cycle.

New evidence for nitrogen fixation within the Italian white truffle Tuber magnatum.

Diversity of nitrogen-fixing bacteria and the nitrogen-fixation activity was investigated in Tuber magnatum, the most well-known prized species of Italian white truffle. Degenerate PCR primers were applied to amplify the nitrogenase gene nifH from T. magnatum ascomata at different stages of maturation. Putative amino acid sequences revealed mainly the presence of Alphaproteobacteria belonging to Bradyrhizobium spp. and expression of nifH genes from Bradyrhizobia was detected. The nitrogenase activity evaluated by acetylene reduction assay was 0.5-7.5µmolC(2)H(4)h(-1)g(-1), comparable with early nodules of legumes associated with specific nitrogen-fixing bacteria. This is the first demonstration of nitrogenase expression gene and activity within truffle.

Morphological and molecular modifications induced by different carbohydrate sources in Tuber borchii.

During the life cycle of mycorrhizal fungi, morphological, genetic and metabolic modifications are induced in the fungus and its symbiotic partner. These changes are influenced by environmental factors: light, gravity, oxygen, temperature, soil type, nutrients, root exudates and the presence of particular bacterial and perhaps fungal and viral populations in the mycorrhizosphere. To determine whether different carbohydrates lead to cell-signalling events and morphofunctional changes in cultured Tuber borchii mycelia, the expression level of genes involved in morphological modifications was investigated using a macroarray technique and real-time RT-PCR. The morphological study showed an increased growth of Tuber mycelia in glucose, while the hyphae were thinner and less branched in sucrose and maltose. This was accompanied by an upregulation of the genes involved in the general cell metabolism, detoxification processes, hyphal growth and cytoskeleton organization. Since glucose is also present in root exudates, the increased expression of these genes might support the hypothesis that glucose can act as a signal for the fungus to indicate the presence of the plant, and to trigger the complex symbiotic process. These mechanisms can lead to morphological modifications, including increased branching of the root which is necessary for the fungus to establish the symbiosis.

Geographical traceability of Italian white truffle (Tuber magnatum Pico) by the analysis of volatile organic compounds.

Results are presented that were obtained on the geographic traceability of the white truffle Tuber magnatum Pico. Solid-phase microextraction coupled to gas chromatography/mass spectrometry (SPME-GC/MS) was employed to characterize the volatile profile of T. magnatum white truffle produced in seven geographical areas of Italy. The main components of the volatile fraction were identified using SPME-GC/MS. Significant differences in the proportion of volatile constituents from truffles of different geographical areas were detected. The results suggest that, besides genetic factors, environmental conditions influence the formation of volatile organic compounds. The mass spectra of the volatile fraction of the samples were used as fingerprints to characterize the geographical origin. Next, stepwise factorial discriminant analysis afforded a limited number of characteristic fragment ions that allowed a geographical classification of the truffles studied.

Effect of storage on biochemical and microbiological parameters of edible truffle species.

The effects of different storage treatments on the most common edible truffle species, such as Tuber magnatum and Tuber borchii (white truffles), Tuber melanosporum and Tuber aestivum (black truffles), were analysed. Biochemical and microbiological profiles were monitored, in order to evaluate possible alterations during truffle preservation. After harvesting, some fresh samples were kept at 4°C for 30days, other samples were frozen at -20°C for one month, thawed and preserved at 4°C; the remainder were autoclaved. The biochemical parameters studied were sugar and protein content, the activity of some enzymes involved in the central metabolism of the fungi and the electrophoretic pattern of soluble proteins. Total mesophilic bacteria were also counted. The results obtained showed that the storage at 4°C is the treatment that best preserves the biochemical and microbiological characteristics of fresh truffles. Black truffles were more resistant to biochemical spoilage than the white ones, while T. magnatum was the most resistant to microbial spoilage.

Occurrence and diversity of bacterial communities in Tuber magnatum during truffle maturation.

Tuber magnatum, an ascomycetous fungus and obligate ectomycorrhizal symbiont, forms hypogeous fruit bodies, commonly called Italian white truffles. The diversity of bacterial communities associated with T. magnatum truffles was investigated using culture-independent and -dependent 16S rRNA gene-based approaches. Eighteen truffles were classified in three groups, representing different degrees of ascocarp maturation, based on the percentage of asci containing mature spores. The culturable bacterial fraction was (4.17 +/- 1.61) x 10(7), (2.60 +/- 1.22) x 10(7) and (1.86 +/- 1.32) x 10(6) cfu g(-1) for immature, intermediate and mature ascocarps respectively. The total of bacteria count was two orders of magnitude higher than the cfu g(-1) count. Sequencing results from the clone library showed a significant presence of alpha-Proteobacteria (634 of the 771 total clones screened, c. 82%) affiliated with Sinorhizobium, Rhizobium and Bradyrhizobium spp. The bacterial culturable fraction was generally represented by gamma-Proteobacteria (210 of the 384 total strains isolated, c. 55%), which were mostly fluorescent pseudomonads. Fluorescent in situ hybridization confirmed that alpha-Proteobacteria (85.8%) were the predominant components of truffle bacterial communities with beta-Proteobacteria (1.5%), gamma-Proteobacteria (1.9%), Bacteroidetes (2.1%), Firmicutes (2.4%) and Actinobacteria (3%) only poorly represented. Molecular approaches made it possible to identify alpha-Proteobacteria as major constituents of a bacterial component associated with T. magnatum ascoma, independently from the degree of maturation.

Identification and characterization of the Tuber borchii D-mannitol dehydrogenase which defines a new subfamily within the polyol-specific medium chain dehydrogenases.

A novel NADP(+)-dependent D-mannitol dehydrogenase and the corresponding gene from the plant symbiotic ascomycete fungus Tuber borchii was identified and characterized. The enzyme, called TbMDH, is a homotetramer with two zinc atoms per subunit. It catalyzed both D-fructose reduction and D-mannitol oxidation, although it showed the highest substrate specificity and catalytic efficiency for D-fructose. Co-factor specificity was restricted to NADP(H) and the reaction proceeded via a sequential ordered Bi Bi mechanism. The carbon responsive transcriptional pattern showed that Tbmdh is up-regulated when mycelia are transferred to a culture medium containing D-mannitol or D-fructose. The phylogenetic analysis showed TbMDH to be the first example of a fungal D-mannitol-2-dehydrogenase belonging to the medium-chain dehydrogenase/reductases (MDRs). The enzyme identified a new group of proteins, most of them annotated in databases as hypothetical zinc-dependent dehydrogenases, forming a distinct subfamily among the polyol dehydrogenase family.