Involvement of an extracellular fungus laccase in the flavonoid metabolism in Citrus fruits inoculated with Alternaria alternata

Fungi of the genus Alternaria are responsible for substantial pre-harvest losses in Citrus. In this study a degradative metabolism of flavonoids (flavanones, flavones and polymethoxyflavones) was observed when 'Fortune' mandarin, Citrus limon and Citrus paradisi, fruits were inoculated with Alternaria alternata, a pre-harvest pathogenic fungus. Associated to this flavonic metabolism the de novo synthesis of the phytoalexin scoparone was detected. This metabolism of flavonoids is caused by an extracellular fungus laccase. The kinetic characterisation of this enzyme revealed that the activity was induced by Citrus flavonoids and was dependent on flavonoid concentrations. The enzyme exhibited a Km of 1.9 mM using ABTS as substrate with an optimum pH of 3.5 in citrate buffer 100 mM. The enzyme is active between 15 and 45 °C, the optimum temperature being around 35 °C, although 50% of the initial activity is lost after 45 min at 35 °C. The A. alternata laccase was inhibited by 0.5 mM l-cysteine and by caffeic acid. Study of the substrate specificity of this enzyme revealed that Citrus flavonoids are substrates of A. alternata laccase. These results suggest that the laccase enzyme could be involved in the pathogenesis of A. alternata in Citrus.

Molecular detection of Rickettsia typhi in cats and fleas

Background

Rickettsiatyphi is the etiological agent of murine typhus (MT), a disease transmitted by two cycles: rat-flea-rat, and peridomestic cycle. Murine typhus is often misdiagnosed and underreported. A correct diagnosis is important because MT can cause severe illness and death. Our previous seroprevalence results pointed to presence of human R. typhi infection in our region; however, no clinical case has been reported. Although cats have been related to MT, no naturally infected cat has been described. The aim of the study is to confirm the existence of R. typhi in our location analyzing its presence in cats and fleas.

Methodology/Principal Findings

221 cats and 80 fleas were collected from Veterinary clinics, shelters, and the street (2001-2009). Variables surveyed were: date of collection, age, sex, municipality, living place, outdoor activities, demographic area, healthy status, contact with animals, and ectoparasite infestation. IgG against R. typhi were evaluated by indirect immunofluorescence assay. Molecular detection in cats and fleas was performed by real-time PCR. Cultures were performed in those cats with positive molecular detection. Statistical analysis was carried out using SPSS. A p < 0.05 was considered significant.

Thirty-five (15.8%) cats were seropositive. There were no significant associations among seropositivity and any variables. R. typhi was detected in 5 blood and 2 cultures. High titres and molecular detection were observed in stray cats and pets, as well as in spring and winter. All fleas were Ctenocephalides felis. R. typhi was detected in 44 fleas (55%), from shelters and pets. Co-infection with R. felis was observed.

Conclusions

Although no clinical case has been described in this area, the presence of R. typhi in cats and fleas is demonstrated. Moreover, a considerable percentage of those animals lived in households. To our knowledge, this is the first time R. typhi is detected in naturally infected cats.

Beneficial action of Citrus flavonoids on multiple cancer-related biological pathways

Attempts to control cancer involve a variety of means, including the use of suppressing, blocking and transforming agents. Suppressing agents prevent the formation of new cancers from pro-carcinogens, blocking agents prevent carcinogenic compounds from reaching critical initiation sites, while transformation agents act to facilitate the metabolism of carcinogenic components into less toxic materials or to prevent their biological actions. Flavonoids can act as all three types of agent. Epidemiological and animal studies suggest that flavonoids have a protective effect against cardiovascular diseases and some types of cancer. Although flavonoids have been studied for about 50 years, the cellular mechanisms involved in their biological action are still not completely understood. In recent years, experimental studies have provided growing evidence supporting the beneficial action of flavonoids on multiple cancer-related biological pathways (carcinogen bio-activation, cell-signaling, cell cycle regulation, angiogenesis and inflammation). Within the last decade, reports on flavonoid activity have largely associated with enzyme inhibition and anti-proliferative activity. Many of these studies have pointed to a structural-functional relationship, in that the antioxidant, enzyme-inhibition or antiproliferative activities of flavonoids are dependent on particular structural motifs. Our own studies have shown that structural factors would explain the antioxidant, antiproliferative and antimetastatic properties of some citrus flavonoids. In this paper we discuss the relation between each structural factor and the anticancer activity of Citrus flavonoids.

Molecular detection of a Hepatozoon species in stray cats from a feline colony in North-eastern Spain

Within the framework of a local animal health programme, the presence of ectoparasites and haemoparasites was investigated in a colony of 25 cats in Barcelona. Diagnosis was performed both by standard parasitological procedures and molecular techniques. All cats were negative to haematozoan infection by microscopic examination of blood smears. However, Hepatozoon spp. was found in four cats as shown by amplification and sequencing of the 18S rRNA gene. Cat isolates were 100% identical to the isolate Hepatozoon spp. (Spain 2) from Southern Spain. This is the first time that Hepatozoon spp. has been identified in cats from Northern Spain.

The role of wild boar (Sus scrofa) in the eco-epidemiology of R. slovaca in Northeastern Spain

Rickettsia slovaca is considered the etiological agent of tick-borne lymphadenopathy (TIBOLA), an emerging disease transmitted by tick bites. Dermacentor marginatus constitutes the most important vector and wild boar (Sus scrofa) is the main wild host in our area. The epidemiology of this tick-borne rickettsioses has not been completely clarified. During hunting season 2004, wild boar sera sample were collected from northeastern Spain. Ticks were collected both from wild boar and from flagging vegetation in the same areas where wild boar were hunted. Serologic study was carried out using the immunofluorescent antibody (IFA) technique. Ticks were identified as D. marginatus and Rhipicephalus uranicus. Based on sequence analysis on ompA gene, R. slovaca was identified in 30.5% D. marginatus ticks removed from wild boar and in 33.3% D. marginatus collected from flagging vegetation. Rickettsia sp. RpA4 was identified in 4 specimens of D. marginatus removed from wild boar. Twelve of 23 wild boar were seropositive to R. slovaca. Results suggested wild boar are exposed to R. slovaca infection and this pathogen is well established in the wild cycle of D. marginatus in our area.

Dysfunctionality of the xylem in Olea europaea L. Plants associated with the infection process by Verticillium dahliae Kleb. Role of phenolic compounds in plant defense mechanism

Xylem ultrastructural modification and the possible participation of phenolic compounds in the natural defense or resistance mechanisms of olive plants infected with Verticillium dahliae Kleb. were studied. Microscopic study showed that the mycelium propagated and passed from one element to another through the pit. The formation of tyloses and aggregates contributed to obstruction of the xylem lumen. In vivo changes in the levels of these phenolic compounds in infected olive plants and their antifungal activity against Verticillium dahliae Kleb., as revealed by in vitro study, strongly suggest that they are involved in natural defense or resistance mechanisms in this plant material, the most active being quercetin and luteolin aglycons, followed by rutin, oleuropein, luteolin-7-glucoside, tyrosol, p-coumaric acid, and catechin. .

Prevalence of Rickettsia slovaca in Dermacentor marginatus ticks removed from wild boar (Sus scrofa) in northeastern Spain

Rickettsia slovaca, the causative agent of TIBOLA, is transmitted by Dermacentor ticks. Dermacentor marginatus is the most widely species distributed in northeastern Spain, and the wild boar constitutes the main host. D. marginatus ticks were collected from hunter-killed wild boar and were tested by PCR/RFLP. Rickettsial DNA-positive ticks were sequenced using the ompA PCR primers. The prevalence of R. slovaca in D. marginatus ticks was 17.7%. Other spotted fever group rickettsiae were detected in ticks, but these were not definitely identified.

Serological Evidence of Ehrlichia spp. Exposure in Cats from Northeastern Spain

There is little information about Ehrlichia canis as an infectious agent in cats. In order to estimate the prevalence of antibodies to E. canis in the feline population, 235 cat sera were analysed by indirect fluorescent-antibody test. With the objective to determine some risk factors associated with seropositivity, serum samples were divided into two groups: urban stray cats and pet cats. The seroprevalence detected was 17.9%. Most positive sera (83.3%) showed low antibody titres (<1:80). Seropositivity was very similar when comparing the two groups of animals: 17.4% in urban stray cats and 18.4% in pet cats. Results revealed that cats are exposed to Ehrlichia spp. infection, as the low antibody titres detected and the serological cross-reactivity between Ehrlichia species do not allow us to confirm E. canis exposure.

Flavonoid distribution during the development of leaves, flowers, stems, and roots of Rosmarinus officinalis. postulation of a biosynthetic pathway

The distribution of seven flavonoids, eriocitrin, luteolin 3'-O-beta-d-glucuronide, hesperidin, diosmin, isoscutellarein 7-O-glucoside, hispidulin 7-O-glucoside, and genkwanin, has been studied in Rosmarinus officinalis leaves, flowers, stems, and roots during plant growth. The maximum level reached by luteolin 3'-O-beta-d-glucuronide in leaves during June-August suggests the existence of a delay between the activation of the enzymes involved in the flavanone and flavone biosynthesis. The presence of hesperidin and diosmin in the vascular system is significant, and hesperidin shows even higher levels than the phenolic diterpenes and rosmarinic acid. The distribution of flavonoids observed in R. officinalis suggests a functional and structural relationship between phytoregulators and flavonoids, where flavonoids would be "protectors" of the activity of phytoregulators. A hypothesis for the general pathway of biosynthesis of these compounds in plants of the family Labiatae is proposed.

Changes in the levels of polymethoxyflavones and flavanones as part of the defense mechanism of Citrus sinensis (cv. Valencia Late) fruits against Phytophthora citrophthora

Phytophthora citrophthora causes serious losses in Citrus fruits through brown rot lesion. The effect of infection with P. citrophthora on Citrus sinensis (cv. Valencia Late) fruits was studied, with particular reference to the levels of the flavanones hesperidin and isonaringin and the polymethoxyflavones sinensetin, nobiletin, tangeretin, and heptamethoxyflavone, because flavonoids are most probably involved as natural defense or resistance mechanisms in this genus. Changes in the levels of these flavonoids were detected after infection. The hesperidin and isonaringin contents fell by 13 and 67%, respectively, whereas the contents of their corresponding aglycons, hesperetin and naringenin, increased, suggesting the hydrolyzing effect of this fungus on the glycosylated flavanones. The heptamethoxyflavone, nobiletin, sinensetin, and tangeretin levels increased by 48, 28, 26, and 24%, respectively. The in vitro study revealed that these compounds acted as antifungal agents, the most active being the aglycons (naringenin and hesperetin), followed by the polymethoxyflavones and flavanone glycosides. The participation of these flavonoids in the defense mechanism of this Citrus species is discussed.

Seroprevalence of Toxoplasma gondii Antibodies in Domestic Cats from Barcelona, Spain

Cats are important in the epidemiology of Toxoplasma gondii infection because they are the only hosts that can excrete the environmentally resistant oocysts. Antibodies to T. gondii were determined in serum samples from 220 domestic cats (Felis catus) from Barcelona, Spain, using the modified agglutination test (MAT). Antibodies to T. gondii were found in 99 (45%) of 220 cats, with MAT titers of 1:25 in 26, 1:50 in 57, and > or = 1:500 in 16 cats. Seropositivity (MAT 1:25 or more) was significantly higher in adult (> or = 1 yr old, 49.7% of 153) than in juvenile (< 1 yr old, 34.3% of 67) cats, in feral (51.9% of 131) than in domiciled (34.8% of 89) cats, and in cats living in a group (community) of more than 5 cats (50.7% of 142) than in cats living alone (28.0% of 50). These seropositive cats are likely to have already shed T. gondii oocysts in the environment around Barcelona.

Phenolic diterpenes, flavones, and rosmarinic acid distribution during the development of leaves, flowers, stems, and roots of Rosmarinus officinalis. Antioxidant activity

The distribution of six compounds with three different polyphenol skeletons have been studied in Rosmarinus officinalis: phenolic diterpenes (carnosic acid, carnosol, and 12-O-methylcarnosic acid), caffeoyl derivatives (rosmarinic acid), and flavones (isoscutellarein 7-O-glucoside and genkwanin), each showing a characteristic behavior and distribution during the vegetative cycle. Only in leaves were all six compounds present, and the highest accumulation rate was related with the young stages of development. Rosmarinic acid showed the highest concentrations of all the polyphenols in all organs. The distribution of this acid in leaves, flowers, and stems suggests that in the first stages of flower growth, levels were due to in situ biosynthesis, and in the last stages, the contribution of transport phenomena was increased. The antioxidant activity of six extracts with different polyphenolic composition was evaluated in aqueous and lipid systems. The results clearly suggest that rosemary extracts are excellent antioxidants in both aqueous and lipid systems.

Prevalence of antibodies to Borrelia burgdorferi sensu lato in southern chamois (Rupicapra pyrenaica) in Spain

Ungulates are involved in the epidemiology of Borreliosis as maintenance hosts for vector tick species. We evaluated the prevalence of antibodies to Borrelia burgdorferi sensu lato in two different populations of southern chamois in Spain. Forty-six sera (40.4%) were positive at titres >/=1 : 64 using an indirect immunofluorescence assay (IFAT).

Increasing resistance against Phytophthora citrophthora in tangelo Nova fruits by modulating polymethoxyflavones levels

The effect of 6-benzylaminopurine on polymethoxyflavone levels in tangelo Nova fruits and the possible participation of these secondary metabolites in defense mechanisms against Phytophthora citrophthora are studied. The in vitro study of the inhibitory effect of these compounds on fungal growth reveals that nobiletin is the most active agent followed by sinensetin, heptamethoxyflavone, and tangeretin. Treatment with 100 ppm of 6-benzylaminopurine increased the levels of these polymethoxyflavones in this Citrus hybrid and also enhanced the in vivo resistance of the fruit to the fungus by approximately 60%.

Bovine piroplasms in Minorca (Balearic Islands, Spain): a comparison of PCR-based and light microscopy detection

The present study provides the first epidemiological data regarding infection by Theileria and Babesia piroplasms in cattle in Minorca. More than 94% of the studied animals were positive for the presence of Theileria sp., and of those, 41.3% were positive for the presence of Theileria annulata. These results indicate that the prevalence of Mediterranean theileriosis caused by T. annulata is very high in Minorcan dairy farms and that other Theileria sp. are also present in the area. The prevalence of infection was similar throughout the study indicating an endemic situation in this island. The use of PCR resulted in significantly higher efficacy of detection of Theileria sp. compared to microscopical observation (MO) of blood smears and allowed the specific discrimination between pathogenic and non-pathogenic theilerias which cannot be accomplished by traditional diagnosis by MO. Babesia infection in the area was mainly due to Babesia bigemina (6.0% of the studied animals were infected), while one animal (0.75%) was found to be infected by Babesia bovis. It was observed that 31% of animals infected with B. bigemina had a concurrent infection of T. annulata. PCR also resulted in a significantly higher efficacy of detection of Babesia sp. compared to MO when infection levels were higher, towards the end of the study period. The results clearly demonstrate that parasitic infection by piroplasms, especially Theileria sp. is common and endemic in the island of Minorca and that PCR is the optimal approach for the detection and discrimination of these important parasites.

Modulation of the biosynthesis of some phenolic compounds in Olea europaea L. fruits: their influence on olive oil quality

The phenolic composition of olive fruits (Olea europaea L.) (cv. Picual, Villalonga, Alfafarenca, and Cornicabra) grown in different areas of Spain was studied by high performance liquid chromatography-mass spectrometry. Different levels of tyrosol, catechin, p-coumaric acid, rutin, luteolin, and oleuropein were observed in the different varieties analyzed. Treating the fruit with 0.3% Brotomax 50 days after anthesis had a beneficial effect on fruit size, oil content, levels of polyphenolic compounds, and Trolox-equivalent antioxidant activity (TEAC) in all the varieties analyzed.

A survey of ticks (Acari: Ixodidae) on dairy cattle on the island of Menorca in Spain

A survey of ticks affecting dairy cattle under extensive management on Menorca island (off the Spanish Mediterranean coast) was performed through 1999-2000 on seven farms. The species collected were Rhipicephalus bursa, R. turanicus, Hyalomma m. marginatum, H. lusitanicum and Boophilus annulatus. The most abundant species were R. bursa and H. m. marginatum, with peaks of 10.7 (in summer) and 7.5 (in spring) ticks/cow, respectively. R. turanicus was scarcely encountered, while B. annulatus and H. lusitanicum were abundant only in a few localities. The mild climate and adequate vegetation on the island provide satisfactory habitat for extended periods of tick activity, as compared with other regions where these ticks have been collected. The competence of the ticks as vectors for pathogens and the difficulty of using acaricide treatments in the region are discussed.

A comparative study of the accuracy of Ranawat's and Pierchon's methods to determine the centre of rotation in bilateral coxopathy

OBJECTIVE

The objective of the study was to compare two methods (Ranawat's and Pierchon's) used to determine the centre of rotation of the hip and establish which method calculates a position nearer to the real centre of rotation.

PATIENTS AND DESIGN

We selected 24 patients with unilateral osteoarthritis of the hip. The centre of rotation of the healthy hip was determined in two consecutive radiographic studies by superimposing a template of circles and using two axes as the reference lines (X-axis=teardrop line; Y-axis=a line perpendicular to the X-axis, drawn from the intersection of the ilio-ischiatic line and the teardrop line). After ensuring the stability of these references, both methods were applied to the same radiograph to determine which one established a centre of rotation nearer to the anatomical centre identified by the template of circles.

RESULTS

When the values for the healthy hip are compared with those obtained using Ranawat's method, highly significant differences are observed for both X (P<0.0001) and Y (P<0.0001). When the results for the healthy hip are compared with the values obtained using Pierchon's method, neither the X (P=0.722 ) nor the Y values (P=0.112) show any significant differences. It would be advisable to use Pierchon's method to determine the centre of rotation during the preoperative planning for a total hip arthroplasty when the anatomical alteration is bilateral.

Antioxidant activity and radioprotective effects against chromosomal damage induced in vivo by X-rays of flavan-3-ols (Procyanidins) from grape seeds (Vitis vinifera): comparative study versus other phenolic and organic compounds

The quantitative distribution of several flavan-3-ols was determined using HPLC in a grape (Vitis vinifera) seed extract (GSE) of four cultivars grown in the region of Murcia. Polymer >/= C(4) units made up the largest group of procyanidins in the GSE (90.92%, expressed as HPLC % area). The antioxidant activity of GSE and other reference compounds was investigated by measuring their ability to scavenge the ABTS(*)(+) radical cation (TEAC). The most effective compounds were, in order: GSE > rutin > (+)-catechin > diosmin >/= ascorbic acid. The radioprotective effects of GSE and other reference compounds were determined by using the micronucleus test for anticlastogenic activity, any reduction of the frequency of micronucleated polychromatic erythrocytes (MnPCEs) being evaluated in the bone marrow of mouse exposed to X-rays. The most effective compounds were, in order: GSE > rutin > dimethyl sulfoxide (DMSO) > ascorbic acid > 6-n-propyl-2-thiouracil-6c (PTU) > diosmin. The higher ABTS(*)(+) scavenging capacity and anticlastogenic activity of GSE can be explained, structurally, by the high number of conjugated structures between the catechol groups in the B-rings and the 3-OH free groups of the polymeric polyphenolic skeleton and, in addition, by the stability of the aroxyl flavonoid radical generated in the above processes.

Distribution of flavone glycoside diosmin in Hyssopus officinalis plants: changes during growth

A study of the flavonoid composition of Hyssopus officinalis L. (Lamiaceae) plants using high-performance liquid chromatography and NMR spectroscopy revealed the presence of diosmin as the major flavone. The maximum levels of this secondary compound are located in sepals and leaves, which represent 51 and 40.5%, respectively, of the total content of diosmin in whole plant. The presence of isoferulyl D-glucose ester in this plant material was also revealed.

Phenotypic and genotypic characterization of spotted fever group Rickettsiae isolated from Catalan Rhipicephalus sanguineus ticks

Eighty-nine Rhipicephalus sanguineus ticks and 21 Rhipicephalus bursa ticks collected in Catalonia were tested by the hemolymph test to establish their infection rate with spotted fever group rickettsiae. By Giménez staining, 11.2% of the R. sanguineus isolates and 0% of the R. bursa isolates were found to contain rickettsia-like organisms. Six spotted fever group rickettsial strains (Bar29, Bar31, Gir4, Tar1, Tar2, and Tar3) were isolated from these ticks and were characterized by phenotypic and genotypic analyses. PCR followed by restriction fragment length polymorphism analysis showed that the six strains were identical and were characterized by the same restriction profiles as a strain, Mtu5, previously isolated from Rhipicephalus turanicus ticks in the South of France. Microimmunofluorescence serotyping, sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the purified organisms, and Western blot (immunoblot) assay with mouse polyclonal sera confirmed this observation. Pulsed field gel electrophoresis of the whole genome of three of the strains showed that, although closely related, the profile of Tar1 was slightly different from that of the Bar strains. Phylogenetic analysis showed that this new rickettsial sero- and genotype, which will be named the "Catalan strain," is closely related to Rickettsia massiliae. This strain shows an unexpected resistance to rifampin. The epidemiological implications of these findings are considered.

Effect of ethylene on naringin, narirutin and nootkatone accumulation in grapefruit

This paper studies the effect of different concentrations of ethephon on the levels of the sesquiterpene, nootkatone, and of the flavanones, naringin and narirutin, in grapefruit fruits. The results show that nootkatone synthesis and/or accumulation was stimulated by all the concentrations of ethephon assayed, while the levels of naringin and narirutin in the rind diminished. These results open up new perspectives concerning the possible regulation of the secondary metabolism of the plants.

Bioproduction of neohesperidin and naringin in callus cultures of Citrus aurantium

The accumulation of both neohesperidin and naringin as major flavonoids in callus cultures of bitter orange (Citrus aurantium) was demonstrated using high performance liquid chromatography with a diode-array detector. The identity of both compounds was confirmed by their corresponding nuclear magnetic resonance spectra. The levels of neohesperidin are higher than those of naringin in callus culture, as they are in immature fruit, and high concentrations of both are found in young tissues such as immature fruits and the outer zone of calli.

Accumulation of the sesquiterpenes nootkatone and valencene by callus cultures of Citrus paradisi, Citrus limonia and Citrus aurantium

The production of the sesquiterpenes nootkatone and valencene by callus cultures of Citrus species is described. The levels of these compounds were examined by gas chromatography-mass spectrometry and their yields were compared with the amounts found in mature fruits. A simultaneous increase and decrease in the levels of nootkatone and valencene, respectively, were observed with the aging of callus cultures of Citrus paradisi. These results suggest that valencene might be a possible precursor of nootkatone in this species. The high level of nootkatone detected in 9-month-old callus cultures of Citrus paradisi might be associated with the corresponding cell morphological changes observed.