Serum progesterone is lower in ovarian stimulation with highly purified HMG compared to recombinant FSH owing to a different regulation of follicular steroidogenesis: a randomized controlled trial.

STUDY QUESTION: Does ovarian stimulation with highly purified (hp)-HMG protect from elevated progesterone in the follicular phase compared to recombinant FSH (r-FSH) cycles through a different regulation of follicular steroidogenesis? SUMMARY ANSWER: hp-HMG enhanced the Δ4 pathway from pregnenolone to androstenodione leading to lower serum progesterone at the end of the cycle, while r-FSH promoted the conversion of pregnenolone to progesterone causing higher follicular phase progesterone levels. WHAT IS KNOWN ALREADY: Elevated progesterone in the follicular phase has been related to lower clinical outcome in fresh IVF cycles. Progesterone levels are positively correlated to ovarian response, and some studies have shown that when r-FSH alone is used for ovarian stimulation serum progesterone levels on the day of triggering are higher than when hp-HMG is given. Whether this is caused by a lower ovarian response in hp-HMG cycles or to a difference in follicular steroidogenesis in the two ovarian stimulation regimens has not been well characterized. STUDY DESIGN, SIZE, DURATION: A randomized controlled trial including 112 oocyte donors undergoing ovarian stimulation with GnRH antagonists and 225 IU/day of r-FSH (n = 56) or hp-HMG (n = 56) was carried out in a university-affiliated private infertility clinic. Subjects were recruited between October 2016 and June 2018. PARTICIPANTS/MATERIALS, SETTING, METHODS: The women were aged 18-35 years with a regular menstrual cycle (25-35 days) and normal ovarian reserve (serum anti-Müllerian hormone (AMH) = 10-30 pMol/l) undergoing ovarian stimulation for oocyte donation. FSH, LH, estradiol (E2), estrone, progesterone, pregnenolone, 17-OH-progesterone, androstenodione, dehidroepiandrostenodione, and testosterone were determined on stimulation Days 1, 4, 6, and 8 and on day of triggering in serum and in follicular fluid. Samples were frozen at -20°C until assay. Total exposures across the follicular phase were compared by polynomic extrapolation. MAIN RESULTS AND THE ROLE OF CHANCE: Subjects in both groups were comparable in terms of age, BMI, and AMH levels. Ovarian response was also similar: 17.5 ± 7.9 (mean ± SD) versus 16.5 ± 7.5 oocytes with r-FSH and hp-HMG, respectively (P = 0.49). Serum progesterone (ng/ml) on day of trigger was 0.46 ± 0.27 in the hp-HMG group versus 0.68 ± 0.50 in the r-FSH group (P = 0.010). Differences for progesterone were also significant on stimulation days 6 and 8. The pregnenolone: progesterone ratio was significantly increased in the r-FSH group from stimulation day 8 to the day of trigger (P = 0.019). Serum androstenodione (ng/ml) on day of trigger was 3.0 ± 1.4 in the hp-HMG group versus 2.4 ± 1.1 in the r-FSH group (P = 0.015). Differences in adrostenodione were also significant on stimulation Day 8. The pregnenolone:androstenodione ratio was significantly higher in the hp-HMG group (P = 0.012) on Days 6 and 8 and trigger. There were no other significant differences between groups. Follicular fluid E2, FSH, LH, dehidroepioandrostenodione, androstenodione, and testosterone were significantly higher in the hp-HMG than r-FSH group. No differences were observed for progesterone, estrone, 17-OH-progesterone, and pregnenolone in follicular fluid. LIMITATIONS, REASONS FOR CAUTION: All women included in the study were young, not infertile, and had a normal BMI and a good ovarian reserve. The findings might be different in other patient subpopulations. Hormone analyses with immunoassays are subject to intra-assay variations that may influence the results. WIDER IMPLICATIONS OF THE FINDINGS: Stimulation with hp-HMG may prevent progesterone elevation at the end of the follicular phase because of a different follicular steroidogenesis pathway, regardless of ovarian response. This should be considered, particularly in patients at risk of having high progesterone levels at the end of the follicular phase when a fresh embryo transfer is planned. STUDY FUNDING/COMPETING INTEREST(S): Roche Diagnostics provided unrestricted funding for all serum and follicular fluid hormone determinations. J.L.R., M.M., and A.P. have nothing to declare. E.B. has received consulting fees from Ferring, Merck, Gedeon Richter, and Roche and has participated in a research cooperation with Gedeon-Richter. In addition, the author has participated in speakers' bureau and received fees from Ferring, Gedeon Richter, Merck, and Roche. P.A. has received consulting fees from MSD and has participated in speakers' bureau and received fees from Ferring. P.A. also declares travel/meeting support from MSD. E.L. has received consulting fees from Ferring and MSD. In addition, the author has participated in a research cooperation with Gedeon-Richter. Also, the author has participated in speakers' bureau and received fees from Ferring and IBSA, as well as travel/meeting support from IBSA and Gedeon Richter. E.B., P.A., and E.L. also own stocks in IVIRMA Valencia. TRIAL REGISTRATION NUMBER: NCT: NCT02738580. TRIAL REGISTER DATE: 19 February 2016. DATE OF FIRST PATIENT'S ENROLMENT: 03 October 2016.

Left Renal Vein Division for Juxtarenal Aortic Exposure: Influence on Renal Function and Role of the Communicating Lumbar Vein.

BACKGROUND: In this study, we evaluate the outcome of renal function in patients undergoing juxtarenal abdominal aortic aneurysm repair with or without division of the left renal vein with special focus on the role of the communicating lumbar vein. METHODS: A retrospective analysis of prospectively collected data of 110 patients undergoing elective juxtarenal abdominal aortic aneurysm repair between 2000 and 2018 was performed. The demographic characteristics and comorbidities were reviewed in detail and the renal function was analysed pre- and post-operatively. The cohort of patients was split into group A (left renal vein divided) and B (left renal vein mobilised). Group A was further sub-analysed regarding the presence of a communicating lumbar vein on preoperative imaging data (group A+ = vein present, group A- = no communicating lumbar vein present). RESULTS: The patients were matched well regarding their demographic characteristics and comorbidities. In the analysis of renal function, no statistically significant difference could be detected between group A and B. In the sub-analysis of group A, the group with a communicating lumber vein (group A+) turned out to have a significantly better renal function in the long term (sCrea 0.87 vs. 1.51; p = 0.016). CONCLUSION: Ligation of the left renal vein is a safe procedure in surgery of juxtarenal aortic aneurysms regarding the outcome of the renal function. A communicating lumbar vein between the left renal vein and the left ascending lumbar vein seems to play a key role to provide venous drainage after division of the left renal vein.

Venous Thrombo-Embolism in Hospitalized SARS-CoV-2 Patients Treated with Three Different Anticoagulation Protocols: Prospective Observational Study.

The purpose of this study is to assess thrombotic risk in CoViD-19/pneumonia patients with acute respiratory failure and to compare populations treated with three different antithrombotic prophylaxis protocols. The primary outcome is to analyze the prevalence of thrombotic events in hospitalized patients, while the secondary outcome is to analyze the correlation between different anticoagulation targets with thrombotic events. All patients referred to our hospital for acute respiratory failure due to COVID-19 pneumonia between 18 and 31 May 2020 were included. Seventy-four patients were enrolled (44 men and 30 women, average age 68.6). Diagnosis of venous thromboembolism was made in 21 cases (28.4%) and thrombotic events were associated with positive pressure ventilation support (p = 0.024) and hospitalization in ICU (p < 0.0001). These patients presented higher levels of D-dimer (p < 0.0001) and their hospital length of stay was >16 days longer. Forty-seven out of 74 patients (63.5%) received intermediate or therapeutic dose of anticoagulation, while twenty-seven patients (34.5%) received standard antithrombotic prophylaxis. The analysis showed that an intermediate or therapeutic dose of anticoagulation did not decrease the prevalence of thrombotic events. On the other hand, six patients reported severe hemorrhagic complications. Despite intermediate or therapeutic-dose of anticoagulation, a high number of patients with acute respiratory failure secondary to COVID-19 developed thrombotic complications.

Hand-assisted laparoscopic surgery versus endovascular repair in abdominal aortic aneurysm treatment.

OBJECTIVE: Hand-assisted laparoscopic surgery (HALS) for the treatment of abdominal aortic aneurysm (AAA) has shown promising initial results compared with traditional surgery, but its efficacy remains highly debated. The aim of this monocentric, retrospective study was to investigate differences in morbidity, mortality, and reintervention rates between endovascular aneurysm repair (EVAR) and HALS, in the medium- and long-term follow-up in a highly selected population. METHODS: We treated 977 patients consecutively for nonurgent AAA from January 2006 to December 2013; among them, 615 (62.9%) underwent open surgery, 173 (17.7%) HALS, and 189 (19.3%) EVAR. For this study, only patients treated with HALS or EVAR were considered. A subsequent selection process was carried out to identify the patients with clinical characteristics and aneurysm morphology amenable to either of these treatments. The final study cohort included 229 patients; 92 (40.2%) underwent HALS and 137 (69.8%) received EVAR. The two populations were homogeneous for clinical and demographic characteristics. RESULTS: The mean duration of follow-up was 57 ± 28 months (50 ± 24 months in the EVAR group and 67 ± 29 months in the HALS group; range, 2-110 months). No deaths and no statistically significant differences in severe complications or reinterventions were observed over the perioperative period (30 days). Length of stay was significantly shorter after EVAR, because the need for and length of stay in the intensive care unit were decreased. Three postoperative deaths (in-hospital mortality >30 days: HALS, 2.2%; EVAR, 0.7%; P = .7268) occurred owing to respiratory failure (two patients, one in each group) and multiorgan failure secondary to a bowel ischemia (one patient in the HALS group). Other deaths in the study population were not related to the procedure. In both groups, the major causes of death were cancer (24 cases [36.9%]), cardiovascular causes unrelated to AAA (16 [24.6%]), and chronic obstructive lung disease (10 [15.4%]). In the long-term follow-up period, there was a difference in the overall survival in favor of HALS when compared with EVAR (P = .011). CONCLUSIONS: This retrospective, single-center study shows that, within a population of similar clinical and anatomic characteristics, treatment of AAA with EVAR or HALS does not result in significant differences in early morbidity and mortality. EVAR presents significantly shorter hospital and intensive care unit length of stay, whereas HALS presents a lower aneurysm-related reintervention rate and lower perioperative cost. The strict patient selection in this trial, as is generally the case with AAA treatment, is likely the key to success for both of these techniques.

Reduction of acrylamide formation in fried potato chips by Aureobasidum pullulans L1 strain.

Acrylamide is a potential carcinogenic molecule formed during food heat processing at high temperature (Maillard reaction). In the present study, the ability of the yeast Aureobasidium pullulans to deplete the acrylamide precursor free asparagine in fresh potatoes was investigated. A. pullulans applied before final frying changes the free amino acid composition of potatoes, decreasing the content of free asparagine by 16% and reducing acrylamide by 83% in fried potatoes. Potato browning was also reduced by yeast treatment without negative drawbacks on chip taste. This yeast, commonly used in fruit postharvest disease control, can therefore also be applied in potato and bakery industries to reduce food acrylamide content.

Colonic Ischemia after Standard Endovascular Abdominal Aortic Aneurysm Repair, a Rare but Dangerous Complication.

Colonic ischemia (CI) after abdominal aortic aneurysm repair, although rare, is associated with severe prognosis. Endovascular aneurysm repair (EVAR) is becoming the standard of practice in most vascular centers, and it also may reduce CI incidence in comparison with conventional open repair. We report 2 cases of fatal CI after 636 standard EVAR procedures performed at our institution, from January 1998 to December 2017. Both patients were electively treated by highly skilled operators. In one patient, presenting early CI, EVAR procedure was complicated by intraoperative common iliac artery rupture. The other one, presenting CI in seventh postoperative day, had a history of previous left hemicolectomy. In both patients, CI with leakage of fecal material in the abdominal cavity was confirmed by surgical exploration. Only few cases of CI after EVAR have been reported in literature, and the etiology of this complication remains uncertain. While saving the inferior mesenteric artery is almost impossible during standard EVAR, the preservation of hypogastric arteries could play an important role, especially after colonic surgery, but other factors should also be considered. Our preliminary, although limited experience, seems to suggest that in CI developing, intraoperative persistent hypotension and hypogastric branches distal embolization have both a role that should be better addressed.

Postharvest application of brassica meal-derived allyl-isothiocyanate to kiwifruit: effect on fruit quality, nutraceutical parameters and physiological response.

The use of natural compounds to preserve fruit quality and develop high value functional products deserves attention especially in the growing industry of processing and packaging ready-to-eat fresh-cut fruit. In this work, potential mechanisms underlying the effects of postharvest biofumigation with brassica meal-derived allyl-isothiocyanate on the physiological responses and quality of 'Hayward' kiwifruits were studied. Fruits were treated with 0.15 mg L-1 of allyl-isothiocyanate vapours for 5 h and then stored in controlled atmosphere (2% O2, 4.5% CO2) at 0 °C and 95% relative humidity, maintaining an ethylene concentration <0.02 µL L-1. The short- and long-term effects of allyl-isothiocyanate on fruit quality traits, nutraceutical attributes, glutathione content, antiradical capacity and the activity of antioxidant enzymes were investigated. The treatment did not influence the overall fruit quality after 120 days of storage, but interestingly it enhanced the ascorbic acid, polyphenols and flavan-3-ol content, improving the antioxidant potential of kiwifruit. The short-term effect of allyl-isothiocyanate was evidenced by an increase of superoxide dismutase activity and of oxidative glutathione redox state, which were restored 24 h after the treatment. The expression levels of genes involved in detoxification functions, ethylene, ascorbate and phenylpropanoid biosynthesis, were also significantly affected upon allyl-isothiocyanate application. These results suggest that allyl-isothiocyanate treatment probably triggered an initial oxidative burst, followed by an induction of protective mechanisms, which finally increased the nutraceutical and technological value of treated kiwifruits.

Biocontrol of Monilinia laxa by Aureobasidium pullulans strains: Insights on competition for nutrients and space.

Two Aureobasidium pullulans strains (L1 and L8), able to prevent postharvest fruit decay, were evaluated in order to elucidate how the competition for nutrients and space was involved in their activity against Monilinia laxa, the causal agent of peach brown rot. The competition for nutrients was studied by co-culturing pathogen conidia and antagonists in different conditions of nutrient availability and avoiding contact between them. Both antagonists prevented the germination of conidia of M. laxa in water, reducing germination rate by >35%. However, L1 and L8 showed the lowest inhibition of conidial germination in peach juice at 5%, with a reduction of 12.6% and 13.9% respectively. HPLC amino acid analysis of peach juice revealed that the addition of the yeast suspension greatly modified their composition: asparagine was completely depleted soon after 12h of incubation and was probably hydrolyzed to aspartic acid by the yeasts, as aspartic acid content markedly increased. Pure asparagine and aspartic acid were tested by in vitro trials at the concentrations found in peach juice: both influenced M. laxa growth, but in opposite ways. Asparagine stimulated pathogen growth; conversely, amended medium with aspartic acid significantly inhibited the conidia germination and mycelial development of M. laxa. Scanning Electron Microscopy revealed that both strains showed a great capability to compete with M. laxa for space (starting 8h after treatment), colonizing the wound surface and inhibiting pathogen growth. This study clearly showed that A. pullulans L1 and L8 strains could compete with M. laxa for nutrients and space; this mode of action may play an important role in the antagonistic activity, especially in the first hours of tritrophic host-pathogen-antagonist interaction, although several other mechanisms can interact each other.

Influence of Harvest Date on Bull's Eye Rot of 'Cripps Pink' Apple and Control Chemical Strategies.

The influence of four different harvest times on the bull's eye rot of 'Cripps Pink' apple caused by Neofabraea spp. was investigated in two orchards harvested at four different times. In addition, a control strategy based on chemical treatments performed in preharvest or postharvest was evaluated. Regression analysis between harvest time and disease incidence revealed high r2 values (>0.75). All preharvest fungicide treatments significantly (P < 0.0085) reduced the bull's eye rot incidence; however, thiophanate-methyl (achieving >87% control) was more effective than a mixture of pyraclostrobin and boscalid (<80.7%) or fludioxonil (<57.6%), in all trials. Compared with nontreated control fruit, a postharvest treatment with the ethylene inhibitor 1-methylcyclopropene (1-MCP) halved the incidence of infection in three of four experiments. However, a combination of two preharvest treatments with a mixture of pyraclostrobin plus boscalid and one postharvest 1-MPC treatment suppressed bull's eye rot to a significantly (P < 0.00001) greater degree (achieving >87.5% control) than the single treatments with pyraclostrobin and boscalid (<65%) and 1-MCP (<80%) tested alone.

Activities of Aureobasidium pullulans cell filtrates against Monilinia laxa of peaches.

The Aureobasidium pullulans L1 and L8 strains are known as efficient biocontrol agents against several postharvest fungal pathogens. In order to better understand the mechanism of action underneath the antifungal activity of L1 and L8 strains, yeast cell filtrates grown at different times were evaluated in vivo against Monilinia laxa on peach. Lesion diameters on peach fruit were reduced by L1 and L8 culture filtrates of 42.5% and 67% respectively. The ability of these filtrates to inhibit M. laxa conidia germination and germ tube elongation was studied by in vitro assays. The results showed a 70% reduction of conidia germination for both strains while for germ tube elongation, it was 52% and 41% for L1 and L8 culture filtrates respectively. Finally, the activity of cell wall hydrolytic enzymes such as chitinase and glucanase in cell filtrates was analysed and the expression of genes encoding these activities was quantified during yeast growth. From 24h onward, both culture filtrates contained ß,1-3,glucanase and. chitinase activities, the most pronounced of which was N-ß-acetylglucosaminidase. Gene expression level encoding for these enzymes in L1 and L8 varied according to the strain. These results indicate that L1 and L8 strains culture filtrates retain the yeast antagonistic activity and suggest that the production of hydrolytic enzymes plays an important role in this activity.

Biological width formation to immediate implants placed at different level in relation to the crestal bone: an experimental study in dogs.

PURPOSE/AIM: Evaluate differences in bone remodeling, soft tissue reactions and biological width formation around immediate implants placed at different level in relation to the crestal bone in beagle dogs. MATERIAL AND METHODS: The mandibular second, third and fourth premolars of six beagle dogs were extracted, and three implants were placed in the right side of each dog. Healing abutments were adjusted (n = 18). After 4 weeks, the procedure was repeated on the left side of the mandible (n = 18). Randomly, three implants were placed at crestal level (control group), and three implants were placed 2 mm subcrestally (test group) in relation to the crestal bone in each animal. The dogs were sacrificed after 8 weeks from the first surgical procedure, and biopsies were obtained. Samples were processed for ground sectioning. Histometric analysis was carried out to compare buccal and lingual bone resorption, soft tissue behavior and biological width formation in both groups. RESULTS: Crestal bone resorption was higher in the test group when considering the difference of 2 mms (IS-B = 2.05 ± 0.36 mm, control; 1.75 (+2) ± 0.38 mm, test). However, the dimensions of the biological width were similar for both groups (PM-C = 3.34 ± 0.53 mm, control; 3.13 ± 0.55 mm, test). CONCLUSIONS: The alterations that occurred in the peri-implant soft tissues may be related to the hard tissue remodeling, showing similar quantitative findings in the biological width formation in both groups. Even though the subcrestal placement might reduce the distance from the implant shoulder to the first bone-to-implant contact and reestablish the biological width dimension in a most coronal position, it might not have any effect on minimizing the marginal bone loss.

Control of postharvest fungal pathogens by antifungal compounds from Penicillium expansum.

The fungicidal effects of secondary metabolites produced by a strain of Penicillium expansum (R82) in culture filtrate and in a double petri dish assay were tested against one isolate each of Botrytis cinerea, Colletotrichum acutatum, and Monilinia laxa and six isolates of P. expansum, revealing inhibitory activity against every pathogen tested. The characterization of volatile organic compounds released by the R82 strain was performed by solid-phase microextraction-gas chromatographic techniques, and several compounds were detected, one of them identified as phenethyl alcohol (PEA). Synthetic PEA, tested in vitro on fungal pathogens, showed strong inhibition at a concentration of 1,230 µg/ml of airspace, and mycelium appeared more sensitive than conidia; nevertheless, at the concentration naturally emitted by the fungus (0.726 ± 0.16 m g/ml), commercial PEA did not show any antifungal activity. Therefore, a combined effect between different volatile organic compounds produced collectively by R82 can be hypothesized. This aspect suggests further investigation into the possibility of exploiting R82 as a nonchemical alternative in the control of some plant pathogenic fungi.

Evaluation of Penicillium expansum isolates for aggressiveness, growth and patulin accumulation in usual and less common fruit hosts.

Experiments were carried out in vivo and in vitro with four isolates of Penicillium expansum (I 1, E 11, C 28 and I 12) to evaluate their aggressiveness, growth and patulin accumulation in both usual (pears and apples) and less common hosts (apricots, peaches, strawberries and kiwifruits) of the pathogen. The 75% of isolates showed the ability to cause blue mould in all tested hosts. In particular, C 28 and I 1 were the most and the least aggressive isolates, respectively (52.9 and 10.6% infection and 20.7 and 15.4 mm lesion diameters). 'Candonga' strawberries and 'Pinkcot' apricots showed the largest lesion diameters (29.8 and 25.3 mm), followed by 'Conference' pears, 'Spring Crest' peaches and 'Abate Fetel' pears. With the exception of 'Candonga' strawberries, the formation of colonies and mycelial growth of P. expansum isolates on fruit puree agar media (PAMs) was stimulated in comparison to a standard growth medium (malt extract agar, MEA). Two of the most aggressive isolates in our assays (I 12 and C 28) showed the greatest accumulation of patulin both in vitro and in vivo, while the least aggressive isolate (I 1) produced patulin only in a few growth media and cvs. Patulin concentration on fruit PAMs was higher than patulin detected in infected fruit tissues. Apple PAMs were the more favorable substrates for patulin accumulation in vitro (maximum concentration 173.1 and 74.1 µg/mL in 'Pink Lady and 'Golden Delicious' PAMs, respectively) and 'Pink Lady' apples inoculated with the isolate E 11 showed the greatest accumulation of patulin in the whole in vivo assay (33.9 µg/mL). However, infected tissue of cv Golden Delicious showed lower average accumulation of patulin (1.7 µg/mL) than that of cv Pink Lady (19.1 µg/mL), and no significant differences in patulin concentrations were found among 'Golden Delicious' apples and tested cvs of pears, kiwifruits and strawberries. Peaches were highly susceptible to patulin accumulation, showing average concentrations of 27.4 and 18.6 µg/mL in vitro and in vivo, respectively. Apricots were also consistently positive for patulin accumulation, both in vitro (average values of 20.1 µg/mL) and in vivo (average values of 9.4 µg/mL). Our study showed the potential of some less common hosts of P. expansum (in particular peaches and apricots) to support patulin production, indicating that a steady monitoring of patulin contamination should be carried out in fruit substrates other than apples and pears.

Implant platform switching concept: an updated review.

PURPOSE: To review published articles dealing with platform switched implants in order to assess survival rates and clarify their influence both on marginal bone loss around the cervical region of the implant and on soft tissue aesthetics. MATERIAL AND METHODS: PubMed and GallileUM databases were used to identify any studies or clinical cases involving implant platform switching published between January 2000 and August 2008. Studies both of human beings and animals were reviewed whenever they included the relevant implant diameter, length, surface and connection data. RESULTS: Twelve studies of platform switching in humans (75%) and in animal models (25%) were evaluated. Mean implant length was found to be 11.66 +/- 0.2 SD mm and mean diameter was 4.9+/- 0.52 SD mm. CONCLUSION: It was shown that platform switching helps to prevent crestal bone loss after implant placement and helps obtain satisfactory aesthetic results.

Implant platform switching concept: An updated review

Purpose: To review published articles dealing with platform switched implants in order to assess survival ratesand clarify their influence both on marginal bone loss around the cervical region of the implant and on soft tissueaesthetics.Material and Methods: PubMed and GallileUM databases were used to identify any studies or clinical cases involvingimplant platform switching published between January 2000 and August 2008. Studies both of humanbeings and animals were reviewed whenever they included the relevant implant diameter, length, surface andconnection data.Results: Twelve studies of platform switching in humans (75%) and in animal models (25%) were evaluated.Mean implant length was found to be 11.66 ± 0.2 SD mm and mean diameter was 4.9± 0.52 SD mm.Conclusion: It was shown that platform switching helps to prevent crestal bone loss after implant placement andhelps obtain satisfactory aesthetic results (AU)

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Fungicidal Activity of Plant Volatile Compounds for Controlling Monilinia laxa in Stone Fruit.

Nine plant-volatile compounds were tested for their activity against Monilinia laxa, the cause of brown rot in stone fruit. In vitro trials on conidial germination and mycelial growth showed a consistent fungicidal activity of trans-2-hexenal, carvacrol, and citral, whereas trans-cinnamaldehyde, hexanal, (-)-carvone, eugenol, 2-nonanone, and p-anisaldehyde exhibited a progressively lower inhibition. The best inhibitor of conidial germination was trans-2-hexenal (effective dose for 50 and 90% inhibition [ED50 and ED95] = 7.53 and 9.4 µl/liter, respectively; minimal inhibitory concentration [MIC] = 12.3 µl/liter], whereas carvacrol was the best inhibitor of mycelial growth (ED50 and ED95 = 2 and 3.4 µl/liter, respectively; MIC = 6.1 µl/liter). The three most active compounds in in vitro studies also were tested in vivo as postharvest biofumigants. The best control of brown rot was with trans-2-hexenal (efficacy ranging from 46.2 to 80.3%, depending on cultivar), whereas citral and carvacrol resulted in a lower efficacy of 40 and 32.9%, respectively. Fumigation with trans-2-hexenal at concentrations that stopped decay did not cause any visible disorders to plum, whereas it was phytotoxic to apricot, peach, and nectarine and produced off-odors or off-flavors in all species of stone fruit tested.

Biological control of Monilinia laxa and Rhizopus stolonifer in postharvest of stone fruit by Pantoea agglomerans EPS125 and putative mechanisms of antagonism.

Treatment of stone fruits (apricot, peach and nectarine) with Pantoea agglomerans strain EPS125 decreased the incidence and diameter of lesions of brown rot caused by Monilinia laxa and soft rot caused by Rhizopus stolonifer. Root control was achieved on fruits either wounded and subsequently inoculated with the pathogens or non-wounded and naturally infected from orchards. The efficacy of biocontrol was dependent on the concentration of the biocontrol agent and pathogen. At medium to low pathogen dose, optimal EPS125 concentrations were above 10(7) CFU ml(-1). The median effective dose (ED(50)) of EPS125 was 4.5x10(4) in M. laxa and 2.2x10(5) CFU ml(-1) in R. stolonifer. However, EPS125 was more effective in M. laxa than in R. stolonifer as indicated by the ratio between ED(50) of the biocontrol agent and pathogen (K(z)/K(x)) which was 166 and 1263, respectively. Interactions between the strain EPS125 and the fruit surface, and M. laxa and R. stolonifer, were studied to determine the mechanisms of protection from postharvest rots. The strain EPS125 colonizes, grows and survives on stone fruit wounds. Significant inhibition of conidial germination and hyphal growth of R. stolonifer and M. laxa was achieved when the fungal and EPS125 cells were cocultivated on peel leachate or nectarine juice. However, no effect was observed when the antagonist and the pathogen cells were physically separated by a membrane filter which permits nutrient and metabolite interchange. Therefore, a direct interaction between the strain and the pathogen cells is necessary for antagonism, without a significant contribution of the production of antibiotic substances or nutrient competition. Preemptive exclusion by wound colonization and direct interaction with the pathogen is proposed as the mechanism of biocontrol.