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At least 19 recordsLinked to original sources
PubMed2026

Genomes of the ex-type strains of Elsinoë mangiferae and E. perseae, the causal agents of scab on mango and avocado.

Elsinoë species are slow-growing, hemibiotrophic to necrotrophic fungi that cause scab diseases on economically important fruit crops. Genome resources for many host-specific species remain limited. We report high-quality draft genome assemblies for the ex-type strains of Elsinoë mangiferae (CBS 226.50) and E. perseae (CBS 406.34), causal agents of mango and avocado scab, respectively. Among 5 approaches tested, a Nanopore-only NextDenovo assembly produced the most contiguous genomes, yielding 24.5 Mb (E. mangiferae) and 25.1 Mb (E. perseae) assemblies with 13 and 18 contigs, respectively, BUSCO completeness scores of ∼94%, and multiple putative telomere-to-telomere chromosomes. Gene prediction identified 9,134 and 9,243 genes, respectively. Functional annotation revealed enrichment of metabolic and regulatory pathways, including those involved in posttranslational modification, protein transport, and secondary metabolism. Carbohydrate-active enzyme repertoires were small but conserved, consistent with stealth pathogenicity strategies and low plant cell wall degradation. Both genomes encoded large secretomes (>850 proteins), diverse protease repertoires (>300 proteins), Ecp2-like effector proteins, and multiple biosynthetic gene clusters, including clusters with similarity to those associated with elsinochrome and ACT-toxin II biosynthesis, some of which may contribute to host-pathogen interactions and disease development. A large fraction of genes lacked functional characterization, suggesting incomplete databases and/or the presence of lineage-specific genes potentially involved in virulence or host adaptation. These genome resources fill critical gaps for underrepresented Elsinoë species and provide taxonomically anchored references essential for diagnostics, comparative genomics, and research into the molecular basis of host specificity and pathogenicity in scab-causing fungi.

Persea↗
PubMedDate not supplied

Majorenolide and majorynolide: a new pair of cytotoxic and pesticidal alkene-alkyne delta-lactones from Persea major.

From the EtOH extract of the bark of Persea major, two bioactive compounds, majorynolide [1] and majorenolide [2], were isolated by activity-directed fractionation using brine shrimp. Their structures have been elucidated on the basis of spectral data as a pair of new alkene-alkyne delta-lactones, each with an exocyclic alkylidene methine carbon. Both 1 and 2 are moderately cytotoxic, and 2 is selectively pesticidal.

Animals↗
PubMed1990

3-Oxoacyl-(acyl-carrier protein) reductase from avocado (Persea americana) fruit mesocarp.

The NADPH-linked 3-oxoacyl-(acyl-carrier protein) (ACP) reductase (EC 1.1.1.100), also known as 'beta-ketoacyl-ACP reductase', has been purified from the mesocarp of mature avocado pears (Persea americana). The enzyme is inactivated by low ionic strength and low temperature. On SDS/PAGE under reducing conditions, purified 3-oxoacyl-ACP reductase migrated as a single polypeptide giving a molecular mass of 28 kDa. Gel-filtration chromatography gave an apparent native molecular mass of 130 kDa, suggesting that the enzyme is tetrameric. The enzyme is inactivated by dilution, but some protection is afforded by the presence of NADPH. Kinetic constants have been determined using synthetic analogues as well as the natural ACP substrate. It exhibits a broad pH optimum around neutrality. Phenylglyoxal inactivates the enzyme, and partial protection is given by 1 mM-NADPH. Antibodies have been raised against the protein, which were used to localize it using immunogold electron microscopy. It is localized in plastids. N-Terminal amino-acid-sequence analysis was performed on the enzyme, and it shows close structural similarity with cytochrome f. Internal amino-acid-sequence data, derived from tryptic peptides, shows similarity with the putative gene products encoded by the nodG gene from the nitrogen-fixing bacterium Rhizobium meliloti and the gra III act III genes from Streptomyces spp.

3-Oxoacyl-(Acyl-Carrier-Protein) Reductase↗
PubMed1989

Pathological changes in the mammary gland and biochemical changes in milk of the goat following oral dosing with leaf of the avocado (Persea americana).

Two varieties of avocado leaves (Persea americana var Guatemalan and var Mexican) were administered to lactating goats. The Mexican variety was without effect. The Guatemalan variety in doses exceeding 20 g fresh leaf per kg bodyweight, produced damage to the mammary gland with decreased milk production. The lesions were characterised by oedema and reddening, with clots in the large ducts. Microscopically, there was widespread degeneration and necrosis of the secretory epithelium, the necrotic cells sloughing into the lumen. There was no significant cellular inflammatory response. Concentrations of antitrypsin in the milk, indicating changes in vascular permeability, increased rapidly 15 h after a single high dose, coinciding with palpable oedema. Concentrations of NAGase, indicating cell damage, increased after 24 h. Goats given multiple doses followed a similar pattern but the initial response was delayed. The toxic principle, and its mode of action in selectively damaging mammary secretory cells, remains to be determined.

Acetylglucosaminidase↗
PubMed1991

Suspected avocado (Persea americana) poisoning in goats.

A herd of 15 Cameroon goats was suspected of having been poisoned by eating leaves of the Fuerte variety of avocado pear (Persea americana). Two of the affected goats were examined clinically, while necropsies were carried out on 3 of the 4 that had died. The most significant clinical findings were tachycardia, hyperpnoea and evidence of lung oedema. At necropsy severe lung oedema, hydrothorax and hydropericardium were present. Severe myocardial degeneration, necrosis and fibrosis were the major histopathological findings.

Animals↗
PubMed1991

Cardiomyopathy caused by avocado (Persea americana Mill) leaves.

Six of 21 goats feeding on fresh avocado (Persea americana) leaves from pruned trees, showed clinical signs of cardiac distress. Some sheep subsequently dosed experimentally at different dosage rates with the same and other avocado varieties, showed clinical signs of respiratory or cardiac distress and myocardial lesions at autopsy.

Animals↗
PubMed1987

Isolation and characterization of mutants of Streptococcus mutans using selective removal of wild-type cells by agglutination with an agglutinin from Persea americana.

Persea americana agglutinin (PAA), a substance known to bind basic proteins and inhibit the sucrose-independent adherence of Streptococcus mutants to saliva = coated hydroxyapatite (Staat et al., 1980) was used to selectively enrich for mutants defective in a variety of cell surface associated virulence characteristics from cultures UAB62 (PS14 Riff, serotype c), UAB66 (6715 Strr Spcr, serotype g) and UAB77 (GS5, serotype c). Following mutagenesis and growth for segregation and phenotypic expression, washed cells of each strain were exposed to PAA overnight at 37 degrees C. Aggregated cells were removed by low-speed centrifugation and cells remaining in the supernatant fluids were concentrated, grown to stationary phase and the enrichment with PAA repeated. Mutants isolated following enrichment were phenotypically diverse and included strains defective in one or more of the following characteristics: adherence to glass in a sucrose-containing medium, aggregation with sucrose, dextran or PAA. dextranase production, colony morphology, cell or chain morphology, fermentation of sorbitol, lactose, galactose, raffinose, melibiose, or fructose, and production of surface protein antigen A (SpaA). The diversity of mutant phenotypes identified along with the observation that PAA could still cause aggregation (with a lower efficiency) of all mutants leads us to infer that the interaction of this agglutinin with proteins on the S. mutans cell surface is relatively nonspecific and that the observed inhibition of S. mutants attachment to saliva-coated hydroxyapatite caused by PAA is not due to a highly specific unique interaction of PAA with the protein(s) responsible for sucrose-independent adherence.

Agglutination↗
PubMed1990

Studies on the cytochrome P-450 of avocado (Persea [corrected] americana) mesocarp microsomal fraction.

1. Because of the low concentration of cytochrome P-450 in avocado fruit, microsomal fractions were prepared using polyethylene glycol aggregation and low-speed centrifugation, thus avoiding the need for high-speed centrifugation of large volumes of post-mitochondrial supernatant. Recoveries of cytochrome P-450 by this means (0.29 nmol/g tissue) were similar to those after the usual high-speed centrifugation preparation (0.26 nmol/g). The cytochrome P-450 content of tulip bulb (0.30 nmol/g) was similar to that of avocado, but both plant tissues had much lower P-450 contents than did rat liver (13.0 nmol/g). 2. Spectral studies indicate that cytochrome P-450 of avocado mesocarp microsomal fraction binds fewer substrates than does the rat liver enzyme system. Type I binding spectra are given by fatty acids (C7-C14), aryl hydrocarbons (C7-C12), p-chloro-N-methylaniline and N,N-dimethylaniline. Type II binding is seen with inhibitors of mammalian cytochrome P-450 such as metyrapone, and with the imidazole antifungal agents such as clotrimazole. 3. These binding spectra provide a rapid method for identifying possible substrates and inhibitors of avocado cytochrome P-450, and also provide information concerning the nature of the active site of avocado cytochrome P-450. 4. Avocado cytochrome P-450 catalysed the N-demethylation of N,N-dimethylaniline (17.1 nmol/min per nmol P-450) and p-chloro-N-methylaniline (13.1 nmol/min per nmol P-450), and the hydroxylation of lauric (dodecanoic) acid (1.1 nmol/min per nmol P-450).

Aniline Compounds↗
PubMed1989

Avocado (Persea americana) intoxication in caged birds.

Avocados of 2 varieties were mashed and administered via feeding cannula to 8 canaries and 8 budgerigars. Two control budgerigars were given water via feeding cannula. Six budgerigars and 1 canary died within 24 to 47 hours after the first administration of avocado. Deaths were associated with administration of both varieties of avocado. Higher dose was associated with greater mortality. The 2 budgerigars given water were normal throughout the observation period. Results indicated that avocados are highly toxic to budgerigars and less toxic to canaries. Postmortem findings observed in some birds included subcutaneous edema in the pectoral area and hydropericardium.

Animals↗
PubMed1991

Dictyostelium discoideum gene family contains a long internal amino acid repeat.

Two different cDNA clones denoted pTO270-6 and pTO270-11 represent two mRNAs that are developmentally regulated during spore germination in Dictyostelium discoideum. The respective mRNAs are found only during early germination and are not present in other stages of growth or multicellular development. Four different genomic clones that hybridize to sequences that are common to both of the 270 cDNA clones were isolated from Dictyostelium libraries and sequenced. Two are the genes for the two cDNAs, and the other two represent genes that do not seem to be transcribed. All four genomic sequences possess a very unusual internal feature in the deduced protein sequences composed of a monotonous repeat of the tetrapeptide threonine-glutamic acid-threonine-proline. The other portions of the proteins have no homology among themselves. The deduced protein corresponding to the 270-6 gene is very similar to avocado (Persea americana) cellulase. Since cellulose in the spore wall has to be digested during spore germination this suggests that this protein may function as an endo-(1,4)-beta-D-glucanase during germination.

Amino Acid Sequence↗
PubMed1990

Sequence analysis of the Clostridium stercorarium celZ gene encoding a thermoactive cellulase (Avicelase I): identification of catalytic and cellulose-binding domains.

The nucleotide sequence of the celZ gene coding for a thermostable endo-beta-1,4-glucanase (Avicelase I) of Clostridium stercorarium was determined. The structural gene consists of an open reading frame of 2958 bp which encodes a preprotein of 986 amino acids with an Mr of 109,000. The signal peptide cleavage site was identified by comparison with the N-terminal amino acid sequence of Avicelase I purified from C. stercorarium culture supernatants. The recombinant protein expressed in Escherichia coli is proteolytically cleaved into catalytic and cellulose-binding fragments of about 50 kDa each. Sequence comparison revealed that the N-terminal half of Avicelase I is closely related to avocado (Persea americana) cellulase. Homology is also observed with Clostridium thermocellum endoglucanase D and Pseudomonas fluorescens cellulase. The cellulose-binding region was located in the C-terminal half of Avicelase I. It consists of a reiterated domain of 88 amino acids flanked by a repeated sequence about 140 amino acids in length. The C-terminal flanking sequence is highly homologous to the non-catalytic domain of Bacillus subtilis endoglucanase and Caldocellum saccharolyticum endoglucanase B. It is proposed that the enhanced cellulolytic activity of Avicelase I is due to the presence of multiple cellulose-binding sites.

Amino Acid Sequence↗
PubMed1990

Sequencing and expression of a cellodextrinase (ced1) gene from Butyrivibrio fibrisolvens H17c cloned in Escherichia coli.

The nucleotide sequence of a 2.314 kb DNA segment containing a gene (ced1) expressing cellodextrinase activity from Butyrivibrio fibrisolvens H17c was determined. The B. fibrisolvens H17c gene was expressed from a weak internal promoter in Escherichia coli and a putative consensus promoter sequence was identified upstream of a ribosome binding site and a GTG start codon. The complete amino acid sequence (547 residues) was deduced and homology was demonstrated with the Clostridium thermocellum endoglucanase D (EGD), Pseudomonas fluorescens var. cellulosa endoglucanase (EG), and a cellulase from the avocado fruit (Persea americana). The ced1 gene product Ced1 showed cellodextrinase activity and rapidly hydrolysed short-chain cellodextrins to yield either cellobiose or cellobiose and glucose as end products. The Ced1 enzyme released cellobiose from p-nitrophenyl-beta-D-cellobioside and the enzyme was not inhibited by methylcellulose, an inhibitor of endoglucanase activity. Although the major activity of the Ced1 enzyme was that of a cellodextrinase it also showed limited activity against endoglucanase specific substrates [carboxymethylcellulose (CMC), lichenan, laminarin and xylan]. Analysis by SDS-polyacrylamide gel electrophoresis with incorporated CMC showed a major activity band with an apparent Mr of approximately 61,000. The calculated Mr of the ced1 gene product was 61,023.

Amino Acid Sequence↗
PubMed1990

A shared internal threonine-glutamic acid-threonine-proline repeat defines a family of Dictyostelium discoideum spore germination specific proteins.

A cDNA denoted pRK270 hybridizes to two mRNA species in RNA blots. The mRNAs specific to this clone are not expressed during vegetative growth and multicellular development. They are, however, found predominantly during early stages of spore germination, suggesting that their synthesis is rapidly and coordinately turned on during germination. Two different cDNAs named 270-6 and 270-11 were isolated, representing the two mRNAs. DNA blot analysis shows that 270 is a multigene family. Four genes were isolated from Dictyostelium genomic libraries and sequenced. The putative proteins coded for by these genes are about 51,000, 55,000, 76,000, and 100,000 Da. Two of the genes are expressed during spore germination while transcripts for the other two are not present during spore germination, vegetative growth, or the stages of multicellular development studied. The cDNAs and genes code for deduced proteins that possess a very unusual internal amino acid repeat comprised of the tetrapeptide threonine-glutamic acid-threonine-proline. The other portions of the proteins have no homology among themselves. The 270-6 protein shows excellent identity with avocado (Persea americana) cellulase, indicating that it may function as an endo-(1,4)-beta-D-glucanase.

Amino Acid Sequence↗
PubMed1991

endAFS, a novel family E endoglucanase gene from Fibrobacter succinogenes AR1.

The complete nucleotide sequence of endAFS, an endoglucanase gene isolated from the ruminal anaerobe Fibrobacter succinogenes AR1, was determined. endAFS encodes two overlapping open reading frames (ORF1 and ORF2), and it was proposed that a -1 ribosomal frameshift was required to allow contiguous synthesis of a 453-amino-acid endoglucanase. A proline- and threonine-rich region at the C terminus of ORF1 and rare codons for arginine and threonine were coincident with the proposed frameshift site. ENDAFS is proposed to be a member of subgroup 1 of family E endoglucanases, of which endoglucanases from Thermomonospora fusca and Persea americana (avocado) are also members. Endoglucanases from Clostridium thermocellum and Pseudomonas fluorescens form subgroup 2.

Amino Acid Sequence↗
PubMed1979

Structural changes in the pollinated and unpollinated avocado stigma and style.

Structural changes in the pollinated and unpollinated avocado (Persea americana Mill) stigma and style up to 42 h after first opening of the flower were investigated using light and electron microscopy. The pollen tubes grew in the stigma secretion and intercellular substance and initial contact occurred between the plasma membrane of the male and the cuticle and stigma secretion of the female. The pollen tube wall started to develop 15 min after pollination and increased in thickness up to 24 h after pollination. By 18 h after first opening of the flower, starch had disappeared and cell wall thickenings were present in both the pollinated and unpollinated stigma and style. The wall thickenings developed more slowly in the unpollinated than in the pollinated tissue. They contained lipid and were bounded by callose. Degeneration of the cytoplasm of some of the papilla and transmitting tissue cells occurred only following the passage of the pollen tubes and may be of importance in tube nutrition. There was no degeneration in the unpollinated stigma and style and the cytoplasm did not start to lose clarity until 42 h after first opening of the flower.

Cell Wall↗