Overlooked South American noctuid species: revalidation of Feltia llanoi stat. rev. and redescription of Feltia brachystria (Lepidoptera: Noctuidae).

Feltia llanoi (Köhler, 1953) stat. rev. and its hitherto senior subjective synonym Feltia brachystria (Hampson, 1903) are two species of noctuid moths with unusual broadly bipectinate antenna and restricted distribution in central eastern Argentina, southern Brazil, and Uruguay. Examination of the type of specimens and further material from several collections indicates that these names are not synonyms, but valid species, and reveal the occurrence of F. llanoistat. rev. in Brazil. Therefore, F. llanoistat. rev. and F. brachystria are redescribed and the former name is reinstated to species, including taxonomic comments, illustration of some characters of taxonomic importance, and of structures of the male and female genitalia. The species are compared with similar-looking and supposedly closely related species, such as F. chilensis (Hampson, 1903), F. carolia (Schaus, 1929), and F. gypaetina (Guenée, 1852). Additionally, in order to stabilize nomenclature, a lectotype for F. llanoistat. rev. is designated, and Agrotis daguerrei Köhler, 1961 is here recognized as a junior subjective synonym of F. llanoistat. rev. (syn. nov.).

Feltia submontana (Noctuidae, Noctuinae): Redescription, Taxonomy, Life Cycle, and Spatial Distribution of a Neglected South American Potential Pest Species.

Feltia submontana (Köhler, 1961) is redescribed based on specimens from Northwestern Argentina and Central and Southeastern Brazil. Taxonomic comments, photographs of the adults, characters of taxonomic importance, and illustrations of structures of the labial palpus, legs, and male and female genitalia are provided. The species is compared with similar-looking and supposedly closely related species, such as F. hispidula (Guenée, 1852) and F. lilacina (Zerny, 1916). The species, originally described for Argentina, is reported for Brazil for the first time. Most Brazilian specimens come from the "Cerrado" but also from Southeastern Atlantic Forests. The life cycle of F. submontana specimens collected in Planaltina, Distrito Federal, Brazil, is described; the species probably has only a single generation per year and imagines are on the wing in the late autumn and early winter months; the last instar prepupa and pupa pass through aestival diapause. The abundance of F. submontana relative to other species of Agrotis Ochsenheimer, 1816, and Feltia Walker, 1856, in the above-cited locality is accessed through 4 years of standardized collecting with light trap; the species is the second most abundant species of these genera in the area, with about one fifth of the captures, second only to A. ipsilon (Hufnagel, 1766), with about two thirds of the captures, and about two times more abundant than F. subterranea (Fabricius, 1794); the latter two are regarded as important pest species in South America.

Revision of "Aemilia" pagana Species-Group (Lepidoptera: Erebidae: Arctiinae), with a Description of a New Endemic Species and Comments on the Conservation Status.

A taxonomical rearrangement of "Aemilia" pagana species-group is proposed: Leucanopsis pagana (Schaus in Proc Zool Soc London 1894:225-243, 1894) comb. nov. and L. ninae (Orfila in Rev Soc Entomol Argent 21:67-70, 1959) comb. nov. A new endemic species from Pampa de Achala, Córdoba, Argentina, closer to both species, is described: Leucanopsis navarroi sp. nov. These three species can be recognized because the color pattern is the darkest among species of Leucanopsis. Characteristics of male genitalia suggest the nomenclatural rearrangement proposed. Leucanopsis pagana comb. nov. has a wide distribution from the center of Brazil to northeastern Argentina, including southern Paraguay. The known distribution and geospatial analysis suggest that this species is not in danger. Leucanopsis ninae comb. nov. is restricted to only one known locality (Villa Gesell, Buenos Aires). The restricted known distribution, the different land use practices, and geospatial analysis suggest that this species could be endangered. Leucanopsis navarroi sp. nov. is endemic to the high plateau present in the center of Argentina called Pampa de Achala. The known distribution and geospatial analysis suggest that this species could be endangered. Further studies are necessary to determine effectively the conservation status of these three species.

Paracoccidioides brasiliensis, paracoccidioidomycosis, and antifungal antibiotics.

Paracoccidioides brasiliensis is the causative agent of paracoccidioidomycosis (PCM), a human systemic, chronic and progressive mycosis. Preferred antifungals are sulfamethoxazol-trimethoprim, itraconazole, amphotericin B. Treatment is lengthy, the drugs may have undesirable side effects, and some are costly. Occasional resistant strains have been reported. Therefore, the search for more selective and efficient antifungals to treat this and other mycoses continues. Ajoene, chemically derived from garlic, behaves as an antifungal agent against P. brasiliensis and other fungi. Its antiproliferative effects in P. brasiliensis are associated with a reduction of phosphatidyl choline, a concomitant increase in its precursor phosphatidyl ethanolamine, and a large increase in unsaturated fatty acids in the pathogenic yeast phase. The sterol biosynthetic pathway has been largely studied for the search of antifungals. Azoles and allilamines act on differents steps of this pathway. However, they may interfere with similar steps in the host. Hence, the search for drugs that may act on more specific steps is ongoing. One such step focuses on the sterol C-methylations catalyzed by the enzyme (S)-adenosyl-L-methionine: Delta(24) - sterol methyl transferase (SMT). SMT inhibitors such as azasterols and derivatives (AZA1, AZA2, AZA3) have proven highly effective as antiproliferative agents against protozoa and some fungi, among them, P. brasiliensis. Their chemical synthesis and structure, and their molecular electrostatic potential are discussed in order to understand their mechanism of action, and derive rationally designed improvements on these molecules, that would favour a higher efficacy and selectivity.

Chitin synthesis as target for antifungal drugs.

Human mycoses have become a threat to health world-wide. Unfortunately there are only a limited number of antimycotic drugs in use. Promising targets for drugs specific against fungi are those affecting chitin synthesis. Chitin is absent in vertebrates, and is essential for fungal wall integrity. A thorough knowledge of the mechanism of chitin synthesis is required to design specific inhibitors. We review here our current understanding of the process, and the most promising drugs that inhibit it. Chitin is made by chitin synthases requiring specific microvesicles, the chitosomes, for intracellular transport. Fungi contain several chitin synthases, some of which may be essential at a certain stage. This phenomenon is important to take into account for drug design. The most widely studied chitin synthase inhibitors are polyoxins and nikkomycins that probably bind to the catalytic site of chitin synthases. These are not equally susceptible to the drugs. In Saccharomyces cerevisiae the order of sensitivity is: Chs3p>Chs1p>Chs2p. Main problems for their succesful use in vivo are: low permeability, and different susceptibility of fungal species, and variable responses in animal models. Chemical modifications have been proposed to make more potent derivatives. Other synthetic or natural compounds are also promising as possible inhibitors, but their properties are less well known. Rational drug design has proceeded only on the basis of existing inhibitors, because the structure of the active site of chitin synthase is unknown. Undoubtedly, determination of this, and the biosynthetic mechanism will reveal unexpected drug targets in the future.

Biochemical and physiological aspects in the dimorphism of Paracoccidioides brasiliensis.

Paracoccidioides brasiliensis is a dimorphic fungus pathogenic for humans. It shows a yeast like phase at 37 degrees C and a mycelial phase at 23 degrees C. Biochemical aspects of its dimorphism are related to the presence of hormone receptors, regulation of cAMP, or modulation of glucan synthetase activity through cytoplasmic proteinases. These aspects are reviewed herein.

Effects of cyanein and ramihyphin A on the dimorphism of Paracoccidioides brasiliensis.

As a preliminary step in the study of dimorphism in Paracoccidioides brasiliensis, the effects of cyanein and ramihyphin A were studied. These antibiotics have been reported to induce morphological changes in fungi. The results obtained suggest that ramihyphin A induce swelling of hyphae while partially inhibiting Y leads to M transformation with the production of an incipient and swollen mycelium. Cyanein did not affect the mycelial morphology as did ramihyphin A. However, the Y leads to M transformation was inhibited and, also, the M leads to Y transformation was blocked with the production of a few yeast cells which were not released from the mycelium.

alpha-galf I -->6-alpha-mannopyranoside side chains in Paracoccidioides brasiliensis cell wall are shared by members of the Onygenales, but not by galactomannans of other fungal genera.

The water-soluble polysaccharide fraction of the cell wall alkali extract (F1SS) from the mycelial phase of the dimorphic fungus Paracoccidioides brasiliensis is compared with F1SS polysaccharides obtained from the Onygenalean mycelial fungi Ascocalvatia alveolata, Onygena equina and Aphanoascus terreus. These polymers were exclusively composed of mannose and galactose. Data from methylation and NMR analyses reveal that F1SS polysaccharides from the four fungi contain the same residues although in different proportions: [-->2,6)-alpha-D-Manp-(1 -->]; [2)-alpha-D-Manp-(1 -->]; [ -->6)-alpha-D-Manp-(1 -->]; and [alpha-D-Galf-(1 -->]. In P. brasiliensis, the repeating unit of the polysaccharide consists of a backbone of [(1 -->6)-alpha-D-Manp] substituted at the 0-2 position by the disaccharide [alpha-D-Galf-(1 -->6)-alpha-D-Manp-(1 -->], while the remaining 0-2 positions are substituted by single residues of mannose or short chains of (1 -->2)-mannose. The other species had a lower proportion of galactofuranose-containing side chains and higher proportion of mannose-containing side chains. The similarities found among the F1SS polysaccharides from P. brasiliensis and the Onygenalean A. alveolata, A. terreus and O. equina, reveal the close relatedness of all these fungi, show differences with polysaccharides from other fungal genera and agree with the molecular evidence provided in the scientific literature for the placement of P. brasiliensis within the Onygenales.

From magic to science: a journey throughout Latin American medical mycology.

The start of Latin America's love story with fungi may be placed in pre-Hispanic times when the use of fungi in both ritual ceremonies and daily life were common to the native civilizations. But the medical mycology discipline in Latin America started at the end of the 19th Century. At that time, scholars such as A. Posadas, R. Seeber, A. Lutz and P. Almeida, discovered agents of fungal diseases, the study of which has influenced the regional research ever since. Heirs to them are the researchers that today thrive in regional Universities and Research Institutes. Two current initiatives improve cooperation among Latin American medical mycologists. First, the periodical organization of International Paracoccidioidomycosis Meetings (seven so far, from 1979 to 1999); second, the creation of the Latin American Association for Mycology in 1991 (three Congresses, from 1993 to 1999). Latin American publications have increased in international specialized journals such as that from our Society (ISHAM) (from 8% in 1967 to 19% in 1999), and the Iberoamerican Journal of Mycology (Revista Iberoamericana de Micologia; > 40% from 1997 to 1999). In addition, Latin American participation at ISHAM International Congresses has risen from 6.9% in 1975 to 21.3% in 1997, and 43.2% at the 14th ISHAM Congress, held for the first time in a Latin American country, Argentina. A significant contribution of women to the scientific establishment of Latin American medical mycology (e.g., 45% of Latin American papers vs. 18% of other regions published in Journal of Medical and Veterinary Mycology in 1987, had women as authors or coauthors) suggests a better academic consideration of Latin American women against their counterparts in the developed world. Taken together, all these figures reflect the enthusiasm of our Latin American colleagues in the field, despite the difficulties that afflict our region, and affect our work.

[Biochemical regulations in the dimorphism and virulence of pathogenic fungi for humans]. / Regulaciones bioquímicas en el dimorfismo y la virulencia de hongos patógenos para humanos.

Some biochemical mechanisms involved in the processes of virulence and dimorphism in fungi pathogenic for humans are reviewed. Among them, the participation of sulphydryl and disulfide groups, hormone receptors and intra- and extracellular proteinases in Histoplasma capsulatum, Paracoccidioides brasiliensis and Coccidioides immitis.

[Dimorphic fungi: biochemical approach to their dimorphism]. / Los hongos dimórficos: aproximación bioquímica a su dimorfismo.

Dimorphism in pathogenic fungi is reviewed. The phenomenon is divided into four interwoven events: (a) perception of external stimuli by cellular sensors; (b) translation into a biochemical message; (c) alteration of the genomic expression, and (d) structural reorganization towards the morphological change. Experimental evidence is provided. Finally, the possibility that fungal dimorphism may have arisen multiple times throughout evolution, is discussed.

Paracoccidioidomycosis and its etiologic agent Paracoccidioides brasiliensis.

Paracoccidioides brasiliensis is the causative agent of paracoccidioidomycosis, a systemic mycosis endemic to Latin America. In this paper we review clinical, therapeutic and immunological aspects of the disease, as well as the biology and ecology of the fungus, restricting the review to the period 1989-1992.

Chemical and ultrastructural studies on the cell walls of the yeastlike and mycelial forms of Histoplasma farciminosum.

The cell wall of the yeast form of Histoplasma farciminosum contains 13.2% beta-1,3-glucan, 1.0% galactomannan, and 25.8% chitin, whereas the cell wall of mycelial form has 21.8, 4.5, and 40%, respectively, for the same polymers. Also, the cell wall of the yeast form contains alpha-1,3-glucan (13.5%) and an unidentified polymer (21.5%). Chitin, one of the structural polymers of both yeast and mycelial cell walls, is identified as thin isolated fibers (4 nm wide) or in thick bundles (50 nm wide) of fibers. beta-(1-3)-Glucan is also found as thin isolated fibers indistinguishable from isolated fibers of chitin. Fibers 14 nm wide and resembling alpha-(1-3)-glucan fibers of other fungi are found in the yeast form. The results reported here do not give support to the proposal for a different taxonomic classification.

Effect of nucleotides on glucan synthesis in Paracoccidioides brasiliensis.

The activity of Paracoccidioides brasiliensis glucan synthetase was partially inhibited by guanosine 5'-triphosphate, adenosine 3'5'-phosphate and adenosine 5'-triphosphate. This inhibition was more pronounced in the mycelial system than in the yeast one, being higher at 23 degrees C than at 37 degrees C. Addition of ethene diamine tetracetic acid to the incubation mixture inhibited partially the enzymatic activity in mycelial preparations but stimulated it in the yeast system.

Mutants of Paracoccidioides brasiliensis strain IVIC Pb9 affected in dimorphism.

Morphological mutants were isolated after nitrosoguanidine treatment of Paracoccidioides brasiliensis strain IVIC Pb9. Two of these mutants, Pb257 and Pb258, developed a typical mycelia at 23 degrees C, however, the yeast cells which developed at 37 degrees C were indistinguishable from those of the parental strain. A third mutant, strain Pb267, was thermosensitive, grew as yeast-like cells at 23 degrees C, but was unable to survive at 37 degrees C. Morphological observations as well as serological and segregation tests confirmed that the mutant strains originated from P. brasiliensis. Cell wall chemical analyses of the mutant strains grown at 23 degrees C indicated the presence of alkali-soluble, acid-insoluble polysaccharides absent in the parental wild-type strain Pb9 grown under the same conditions. The phenotypes shown by the mutant strains may be related to deficiencies in the proper synthesis of cell wall components of the mycelial phase of this fungus.