- Floral structure and development in the monoecious palm Gaussia attenuata (Arecaceae; Arecoideae). [Journal Article]
- ABAnn Bot 2014; 114(7):1483-95
- CONCLUSIONS: Gaussia attenuata displays a number of floral characters that are likely to be ancestral to the tribe, notably the acervulus flower cluster, which is conserved in the other monoecious genera and also (albeit in a unisexual male form) in the dioecious genera (Wendlandiella and a few species of Chamaedorea). Comparison with earlier data from other genera suggests that large nectariferous pistillodes and early arrest in staminode development might also be regarded as ancestral characters in this tribe.
- First Report of Anthracnose Caused by Colletotrichum gloeosporioides on Schefflera actinophylla in China. [Journal Article]
- PDPlant Dis 2013; 97(7):998
- In China, in mild to warm climates, Schefflera actinophylla is commonly grown as a decorative tree in gardens. When mature, it has bright red flowers in inflorescences with up to 20 racemes that deve…
In China, in mild to warm climates, Schefflera actinophylla is commonly grown as a decorative tree in gardens. When mature, it has bright red flowers in inflorescences with up to 20 racemes that develop in summer or early autumn. From 2008 to 2011, lesions were observed on young and mature leaves in several locations in Guangzhou, China. The first symptoms were circular, necrotic areas that usually developed into irregular, dry, brown to reddish brown or black spots. Spots often first appeared at or near the margins of leaves. Reproductive bodies of the pathogen appeared as black specks in leaf spots. Under a 10× magnification, black, needle-like fungal structures (setae) were observed in the centers of spots on the upper leaf surface. A fungus was isolated from the lesion and was identified as Colletotrichum gloeosporioides (Penz.) Penz. & Sacc. based on cultural characteristics and conidial morphology (1). The voucher isolates were deposited in the Institute of Plant Pathology, Zhongkai University of Agriculture and Engineering. C. gloeosporioides is a species complex (2) and there is a degree of unresolved aspects of taxonomy in this species complex. Cultures on potato dextrose agar (PDA) had aerial white mycelium that turned gray to grayish black after 10 days at 25°C and a 12-h photoperiod and produced salmon to orange conidial masses. Brown, 80 to 120 μm long setae were observed in the acervulus. Conidia 14.1 to 18.0 × 4.0 to 6.1 μm in size were hyaline, thin-walled, aseptate, granular inside, clavate to slightly navicular in shape with an obtuse apex and a truncate base. To identify the fungus, a 588-bp segment of the ITS1-5.8S-ITS2 rDNA region was amplified by PCR and sequenced. The DNA sequence was submitted to GenBank as KC207404. A BLAST search of the DNA sequence showed 99% identity with accessions AY266389.1, EF423519.1, and HM575258.1 of C. gloeosporioides. Pathogenicity tests were conducted under greenhouse conditions at 25 ± 2°C. A total of 15 leaves from three 1-year-old S. actinophylla plants were inoculated with mycelial PDA plugs that were placed on 0.5-cm2 leaf wounds and then wrapped with Parafilm. Control leaves were treated similarly except that they were inoculated with PDA plugs without the fungus. No symptoms developed on control leaves after 10 days. Foliar lesions on inoculated leaves closely resembled those observed in the field. C. gloeosporioides was reisolated consistently from inoculated leaves. Pathogenicity was also tested by spraying leaves of potted S. actinophylla plants about 30 cm in height with 10 ml of a conidial suspension (1 × 105 conidia/ml) prepared from 7-day-old PDA cultures grown at 25°C. Leaves sprayed with distilled water were used as controls. Three plants were inoculated in each of two experiments and were incubated at 25°C and 90% relative humidity in a growth chamber. Tiny brown spots started to develop on all inoculated leaves 5 days after inoculation and the progression of symptom development was similar to that observed in the field. Control leaves remained asymptomatic. C. gloeosporioides was reisolated from inoculated leaves. To my knowledge, this is the first report of C. gloeosporioides causing anthracnose on S. actinophylla in China. References: (1) B. C. Sutton. The genus Glomerella and its anamorph Colletotrichum. In: Colletotrichum Biology, Pathology and Control. CAB International, Wallingford, UK, 1992. (2) B. S. Weir et al. The Colletotrichum gloeosporioides species complex. Stud. Mycol. 73:115, 2012.
- Glomerella Leaf Spot Caused by a Nonhomothallic Strain of Glomerella cingulata on Highbush Blueberry Nursery Plants in Buenos Aires, Argentina. [Journal Article]
- PDPlant Dis 2012; 96(5):764
- In February 2009, irregular-shaped leaf spots affected blueberry (Vaccinium corymbosum L. 'Blue Crisp', 'Misty', and 'Sharp Blue') nursery plants in Buenos Aires. Single-spore cultures on potato dext…
In February 2009, irregular-shaped leaf spots affected blueberry (Vaccinium corymbosum L. 'Blue Crisp', 'Misty', and 'Sharp Blue') nursery plants in Buenos Aires. Single-spore cultures on potato dextrose agar and oat agar showed aerial white mycelium that turned light and dark gray, dark brown acervuli with setae, and a salmon-to-orange conidial mass. Septate, dark brown, 62 to 78 μm long setae were abundant in the acervulus. Conidia were unicellular, hyaline, straight, cylindrical, round at the ends, and averaged 15.2 (12.1 to 16.9) × 5.4 (4.9 to 6.2) μm. Dark brown, ovate to clavate, 10.25 × 6.25 μm (9 to 12 × 5 to 8) appressoria with a noticeable pore formed on slides near the edge of the cover glass. Dark subglobose structures were recorded immersed in the culture medium. No asci or ascospores were observed, indicating a nonhomothallic condition. The fungus was identified as Colletotrichum gloeosporioides (Penz.) Penz & Sacc. (teleomorph Glomerella cingulata (Stoneman) Spauld. & H. Schrenk) with traits similar to those already described (1). DNA was obtained from mycelium with a standard DNA extraction kit and the ribosomal, internal transcribed spacer (ITS) 1 and ITS2 regions were PCR amplified and sequenced with primers ITS1 and ITS4 (2). A BLASTN algorithm search revealed 100% identity of the sequence (535 bp long) with G. cingulata/C. gloeosporioides from citrus and mango and one from coffee identified as C. kahawae (GenBank Accession No. JF908919). The nucleotide sequence was deposited in GenBank (Accession No. JQ340087). Pathogenicity was verified on young plants and detached leaves of highbush blueberry 'Emerald', 'Misty', 'O'Neal', and 'Santa Fe', olive (Olea europaea 'Arbequina'), and marketed fruits of apple, mango, orange, and tomato. Disinfected healthy leaves were inoculated with a 9-mm2 mycelial block and incubated at 24°C with 12 h of light. Young plants were infected by placing the disinfected end of the branches within a micropipette tip filled with mycelium and kept under greenhouse conditions. Asymptomatic fruits of apple, mango, orange, and tomato were inoculated by placing a mycelial block on a small wound made on their surface. Detached leaves of highbush blueberry 'Emerald', 'O'Neal', 'Misty', and 'Santa Fe' showed 0.1 to 1.5 × 0.8 to 2 cm necrotic lesions after 3 days, covering 43 to 100% of the 'Emerald' leaf area after 8 days. Young plants of blueberry 'Emerald' and 'Misty' showed 1.5 to 3 cm necrotic lesions, acervuli, a salmon-orange conidial mass, and death of leaves at 25 days. On olive 'Arbequina', leaf necrotic lesions reached 0.1 to 3.5 cm after 5 days. Symptoms developed slowly on infected tomato fruits while inoculated fruits of apple, mango, and orange showed dark brown lesions that measured 2 to 7 × 1 to 3.5 cm at 5 days. No symptoms were observed on controls. The fungus was reisolated from inoculated plant parts. The disease was previously cited in Argentina (3), but to our knowledge, this is the first report of a nonhomothallic strain of G. cingulata from highbush blueberry colonizing and deteriorating fruits of apple, mango, orange, and tomato. References: (1) J. M. E. Mourde. No 315. CMI Descriptions of Pathogenic Fungi and Bacteria. Kew, Surrey, UK, 1971. (2) T. J. White et al. Page 315 in: PCR Protocols: A Guide to Methods and Applications. Academic Press, San Diego, 1990. (3) E.R. Wright et al. OEPP/EPPO Bull. 28:219, 1998.
- First Report of Anthracnose Caused by Colletotrichum fragariae on Cyclamen in North Carolina. [Journal Article]
- PDPlant Dis 2011; 95(11):1480
- In November 2009, cyclamen (Cyclamen persicum) plants with disease symptoms from a commercial greenhouse operation in the western part of North Carolina were sent to the Plant Diseases and Insect Cli…
In November 2009, cyclamen (Cyclamen persicum) plants with disease symptoms from a commercial greenhouse operation in the western part of North Carolina were sent to the Plant Diseases and Insect Clinic at North Carolina State University. Symptoms consisted of coalescing reddish and tan necrotic leaf spots with concentric circles. Other symptoms included darkened vascular tissue and decay of the corm, large roots, and petioles. Diseased leaves and stems were surface sterilized in 0.5% sodium hypochlorite for 3 min, air dried, and placed in petri dishes containing alkaline water agar. After 3 days of incubation at room temperature, fungal colonies were transferred to acidified potato dextrose agar. Isolation frequency after 5 days was 33% (three of nine pieces) and 16% (one of six pieces) from small leaf spots and petioles, respectively. Pure cultures of isolates were gray and black with abundant, aerial, gray whitish mycelia. Diseased plants were also incubated in a moist chamber at room temperature and sporulation was observed within 7 days. Conidia were tapered with rounded ends and produced in the acervulus and on the tips of setae, which is consistent with the morphology of described isolates of Colletotrichum fragariae. Similar setae were also observed directly on the fine roots of the original sample. The pathogenicity of single-spore cultures was tested by spraying four 2-month-old cyclamen plants with a conidial suspension (106 conidia/ml) and the plants were kept in a humid chamber for 24 h. Noninoculated controls (four plants) were sprayed with distilled water and subjected to the same conditions. The pathogenicity test was also repeated. Inoculated plants and controls were placed in a greenhouse with a temperature range from 22 to 25°C. After 7 to 10 days, symptomatic leaves and stems were observed on all the inoculated plants but not on the control plants. Fungi reisolated from 10 symptomatic leaf tissues had identical morphological features as the original isolates. Fungal DNA was extracted with DNeasy Plant Mini DNA Extraction Kits following the manufacturer's protocol (Qiagen Inc., Valencia, CA). Sequence analysis of the rRNA internal transcribed spacer (ITS) region of the cyclamen isolate (GenBank Accession No. HQ188923), based on the fragment amplified with ITS1 and ITS4 primers, showed 100% similarity to isolates of C. fragariae deposited in GenBank (Accession Nos. FJ172290 [ATCC MYA-4443 from cyclamen] and FJ810510 [ATCC MYA-4442 from silver date palm]) and Florida isolate C16 isolated from strawberry (1). In addition, the morphology and ITS sequences of the cyclamen isolate were identical to those of the C. fragariae voucher isolate from strawberry (GU174546). Results from disease symptoms, colony and spore morphology, pathogenicity tests, and ITS sequence analysis suggest that C. fragariae was the pathogen responsible for the disease symptoms on cyclamens. To our knowledge, this is the first report of a disease caused by C. fragariae on cyclamen in North Carolina and complements an earlier report from Florida (1). Reference: (1) S. J. MacKenzie et al. Plant Dis. 92:1432, 2008.
- First Report of Anthracnose Caused by Colletotrichum gloeosporioides on Pistachio (Pistacia vera) in China. [Journal Article]
- PDPlant Dis 2011; 95(10):1314
- In the 1990s, pistachio (Pistacia vera L. 'Kerman' and 'Peters') was introduced in China. They are found in many orchards in Beijing and Gansu and Hebei provinces, northern China. In 2009, a new dise…
In the 1990s, pistachio (Pistacia vera L. 'Kerman' and 'Peters') was introduced in China. They are found in many orchards in Beijing and Gansu and Hebei provinces, northern China. In 2009, a new disease was observed on leaves, stems, and fruits in pistachio orchards in Gansu Province. Disease incidence in 8- to 12-year-old orchards was 30%. Yield losses reached 25%. Symptoms began as discrete, sunken, black spots, approximately 10 mm in diameter, followed by circular lesions that eventually coalesced with tissue death recorded and orange fructifications developed on lesions. Pieces of diseased leaves, stems, and fruits were surfaced sterilized and placed on 2% potato dextrose agar (PDA) at 25°C. A fungus was consistently isolated. After 10 days, cultures on PDA showed aerial, white mycelium that turned gray to grayish black with a salmon-to-orange conidial mass at 25°C and a 12-h photoperiod. Brown, 80 to 120 μm long setae were observed in the acervulus. Conidia were hyaline, fusiform to nearly straight, and averaged 12 to 18 × 3 to 5 μm. On the basis of morphological characteristics, the fungus was identified as Colletotrichum gloeosporioides (Penz.) Sacc. (2). On PDA, 0.5 μg/ml of benomyl was applied for the sensitivity test (3). Benomyl completely inhibited the growth of the fungus. Mycelial DNA was extracted, PCR amplified using ITS1 and ITS4 primers for the ribosomal DNA internal transcribed spacers 1 and 2, and sequenced. The DNA sequence was recorded in GenBank as No. HQ631378. The DNA sequence was blasted showing 99% identity with Accession Nos. GQ144454 and GU004376, for C. gloeosporioides. Pathogenicity tests were conducted under greenhouse conditions at 25°C. Three replicates of 2-year-old 'Kerman' plants were inoculated with mycelial PDA plugs placed on 0.5-cm2 stem wounds and then wrapped with Parafilm. Controls were inoculated with PDA plugs without the fungus. After 3 weeks, stem cankers were observed on inoculated plants. Control plants remained healthy. Pathogenicity was also tested on injured leaves and fruits. A 10-μl drop of a spore suspension of 104 conidia/ml was applied on 'Kerman' and 'Peters' leaves and 'Kerman' fruits and placed on plates with a wet filter paper at 25°C. Small, black lesions were observed at 2 days after inoculation. At 7 days, necrotic lesions covered the entire surface. C. gloeosporioides was reisolated from necrotic lesions. Controls did not develop symptoms. C. acutatum has been reported on pistachio in Australia (1), but to our knowledge, this is the first report of anthracnose caused by C. gloeosporioides on pistachio. References: (1) G. J. Ash and V. M. Lanoiselet. Australas. Plant Pathol. 30:365, 2001. (2) J. Y. Lu. Plant Pathogenic Mycology. China Agricultural Press, Beijing, 2001. (3) N. A. R. Peres et al. Plant Dis. 86:620, 2002.
- Ontogeny and structure of the acervulate partial inflorescence in Hyophorbe lagenicaulis (Arecaceae; Arecoideae). [Journal Article]
- ABAnn Bot 2011; 108(8):1517-27
- CONCLUSIONS: The results show that a more general definition of the type of partial inflorescence observed within the large subfamily Arecoideae would correspond to a cyme rather than to a floral triad. In spite of their common cymose architecture, the floral triad and the acervulus present differences with respect to the number and arrangement of floral buds, the superficial pattern of development and sexual expression.
- Strawberry Anthracnose: Histopathology of Colletotrichum acutatum and C. fragariae. [Journal Article]
- PPhytopathology 2002; 92(10):1055-63
- ABSTRACT Ontogeny of the invasion process by Colletotrichum acutatum and C. fragariae was studied on petioles and stolons of the strawberry cultivar Chandler using light and electron microscopy. The…
ABSTRACT Ontogeny of the invasion process by Colletotrichum acutatum and C. fragariae was studied on petioles and stolons of the strawberry cultivar Chandler using light and electron microscopy. The invasion of host tissue by each fungal species was similar; however, each invasion event occurred more rapidly with C. fragariae than with C. acutatum. Following cuticular penetration via an appressorium, subsequent steps of invasion involved hyphal growth within the cuticle and within the cell walls of epidermal, subepidermal, and subtending cells. Both species of fungi began invasion with a brief biotrophic phase before entering an extended necrotrophic phase. Acervuli formed once the cortical tissue had been moderately disrupted and began with the development of a stroma just beneath the outer periclinal epidermal walls. Acervuli erupted through the cuticle and released conidia. Invasion of the vascular tissue typically occurred after acervulus maturation and remained minimal. Chitin distribution in walls of C. fragariae was visualized with gold-labeled wheat germ agglutinin. The outer layer of bilayered walls of conidia, germ tubes, and appressoria contained less chitin than unilayered hyphae in planta.
- First Report of Gray Leaf Spot of Mango (Mangifera indica) Caused by Pestalotiopsis mangiferae in Taiwan. [Journal Article]
- PDPlant Dis 2007; 91(12):1684
- Mango (Mangifera indica L.; family Anacardiaceae) is one of the world's most important fruit crops and is widely grown in tropical and subtropical regions. Since 2001, a leaf spot disease was found i…
Mango (Mangifera indica L.; family Anacardiaceae) is one of the world's most important fruit crops and is widely grown in tropical and subtropical regions. Since 2001, a leaf spot disease was found in mango orchards of Taiwan. Now, the disease was observed throughout (approximately 21,000 ha) Taiwan in moderate to severe form, thus affecting the general health of mango trees and orchards. Initial symptoms were small, yellow-to-brown spots on leaves. Later, the irregularly shaped spots, ranging from a few millimeters to a few centimeters in diameter, turned white to gray and coalesced to form larger gray patches. Lesions had slightly raised dark margins. On mature lesions, numerous black acervuli, measuring 290 to 328 μm in diameter, developed on the gray necrotic areas. Single conidial isolates of the fungus were identified morphologically as Pestalotiopsis mangiferae (Henn.) Steyaert (2,3) and were consistently isolated from the diseased mango leaves on acidified (0.06% lactic acid) potato dextrose agar (PDA) medium incubated at 25 ± 1°C. Initially, the fungus grew (3 mm per day) on PDA as a white, chalky colony that subsequently turned gray after 2 weeks. Acervuli developed in culture after continuous exposure to light for 9 to 12 days at 20 to 30°C. Abundant conidia oozed from the acervulus as a creamy mass. The conidia (17.6 to 25.4 μm long and 4.8 to 7.1 μm wide) were fusiform and usually straight to slightly curved with four septa. Three median cells were olivaceous and larger than the hyaline apical and basal cells. The apical cells bore three (rarely four) cylindrical appendages. Pathogenicity tests were conducted with either 3-day-old mycelial discs or conidial suspension (105 conidia per ml) obtained from 8- to 10-day-old cultures. Four leaves on each of 10 trees were inoculated. Before inoculation, the leaves were washed with a mild detergent, rinsed with tap water, and then surface sterilized with 70% ethanol. Leaves were wounded with a needle and exposed to either a 5-mm mycelial disc or 0.2 ml of the spore suspension. The inoculated areas were wrapped with cotton pads saturated with sterile water and the leaves were covered with polyethylene bags for 3 days to maintain high relative humidity. Wounded leaves inoculated with PDA discs alone served as controls. The symptoms described above were observed on all inoculated leaves, whereas uninoculated leaves remained completely free from symptoms. Reisolation from the inoculated leaves consistently yielded P. mangiferae, thus fulfilling Koch's postulates. Gray leaf spot is a common disease of mangos in the tropics and is widely distributed in Africa and Asia (1-3); however, to our knowledge, this is the first report of gray leaf spot disease affecting mango in Taiwan. References: (1) T. K. Lim and K. C. Khoo. Diseases and Disorders of Mango in Malaysia. Tropical Press. Malaysia, 1985. (2) J. E. M. Mordue. No. 676 in: CMI Descriptions of Pathogenic Fungi and Bacteria. Surrey, England, 1980. (3) R. C. Ploetz et al. Compendium of Tropical Fruit Diseases. The American Phytopathological Society. St. Paul, MN, 1994.
- [The morphogenesis and spatial organization of human pineal gland concretions in Alzheimer's disease, schizophrenia, and alcoholism]. [Journal Article]
- APArkh Patol 2006 Sep-Oct; 68(5):20-2
- X-ray microtomography using a wavelength of 0.7 A was used to detect elevated calcium concentration areas that integrate all types of human epiphyseal concretions. They consisted of both concretions …
X-ray microtomography using a wavelength of 0.7 A was used to detect elevated calcium concentration areas that integrate all types of human epiphyseal concretions. They consisted of both concretions and extracellular calcium, which could not be attributed to any particular tissue. There were no concretions outside of these zones. The center of concretion formation was found to be a single source that may be an individual pinealocyte. Comparison of postmortem human epiphyses in normalcy (natural aging), in chronic alcoholism, Alzheimer's disease, and schizophrenia revealed that there were differences in both the number of concretions and their formation topology. In normalcy, the field of elevated calcium concentration was continuous whereas in patients with the study mental diseases, it was divided into separate areas. There is evidence that in mental diseases, the amount of acervulus and its density decrease, which may a marker of the development of these diseases.
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- Soemmerring's work on the nervous system: a view on brain structure and function from the late eighteenth century. [Historical Article]
- AEAnat Embryol (Berl) 2005; 210(5-6):337-42
- Samuel Thomas Soemmerring (1755-1830) was an encyclopaedic anatomist and one of the most experienced and renowned neuro-anatomists in the late eighteenth century. His description and illustration of …
Samuel Thomas Soemmerring (1755-1830) was an encyclopaedic anatomist and one of the most experienced and renowned neuro-anatomists in the late eighteenth century. His description and illustration of the brainstem with its still accepted classification of cranial nerves (1778), the discovery of the acervulus in the epiphysis (1785), his demonstration of the crossing of the optic nerve fibres (1788), and of the macula lutea in the retina of the eye he had discovered in 1791, won him great recognition. Probably, unaware of Francesco Gennari's (1750-1797) and Félix Vicq d'Azyr's (1748-1794) observation, Soemmerring in the final years of the eighteenth century saw the broad white line running through the calcarine cortex of the occipital lobe. Soemmerring's comprehensive textbooks on the nervous system Vom Hirn and Rückenmark, 1788/1792, and Hirn- und Nervenlehre as part of his anatomical handbook Vom Baue des menschlichen Körpers, 1791/2nd edn, 1800, comprise all the knowledge in the field of neuro-anatomy at his time. Although the structure-function relationships mentioned are generally hypothetical, Soemmerring was convinced that mental faculties are executed in certain brain regions. In his treatise Uber das Organ der Seele, 1796, he localized the functions of the soul within the cerebrospinal fluid, which should come into close contact with the demonstrated and presumed nerve endings in the walls of the ventricular cavities. This last attempt of a synthesis of anatomy and metaphysics provoked passionate discussions and was criticised for epistemological reasons. Nevertheless, Soemmerring had moved the brain into the centre of the science of man what led to far-reaching consequences in the complexity of the discourse about man.