The Xenopus laevis genome was screened for putative DNA‐binding gene products by using the ‘finger’ region of the Drosophila gene Krüppel as a probe. The one gene detected, named Xfin, codes for a protein with 37 finger domains that comprise nearly 90% of the protein. In the light of studies by Rhodes and Klug (Cell, 46, 123‐132, 1986), these data suggest that the Xfin protein has the capacity to bind an unusually large stretch (185 bases) of DNA. The Xfin gene is expressed as a maternal and zygotic mRNA that undergoes extensive polyadenylation changes during early development. The Xfin mRNA expression pattern and the potential DNA binding activity of the protein point to the possibility that the Xfin gene may have a role in controlling gene activity during early embryonic development.

A new fluorescence in situ hybridization method using peptide nucleic acid (PNA) probes for identification of Brettanomyces is described. The test is based on fluorescein-labeled PNA probes targeting a species-specific sequence of the rRNA of Dekkera bruxellensis. The PNA probes were applied to smears of colonies, and results were interpreted by fluorescence microscopy. The results obtained from testing 127 different yeast strains, including 78 Brettanomyces isolates from wine, show that the spoilage organism Brettanomyces belongs to the species D. bruxellensis and that the new method is able to identify Brettanomyces (D. bruxellensis) with 100% sensitivity and 100% specificity.Brettanomyces is a well-recognized wine spoilage yeast that causes an undesirable flavor. The sensory character of this "Bretty" flavor is often described as mousiness, barnyard, horse sweat, or Band-Aid (5, 9). Current methods for identification and enumeration of Brettanomyces contamination take 1 to 2 weeks and rely on growth on a semiselective culture medium, followed by final identification by biochemical and physiological analysis and morphology as determined by microscopic examination (3). Morphological characterization of Brettanomyces is somewhat subjective, and there have been various morphological descriptions, such as bud scars, bullet shape, and Mickey Mouse-like. Newer techniques for rapid detection and identification of Brettanomyces, such as an enzyme-linked immunosorbent assay (7) and, more recently, PCR (6), have also been described.The nomenclature of Brettanomyces used in the wine industry differs from that of the recently revised taxonomy of yeasts (11,12). Enologists refer to the spoilage organism as Brettanomyces or "Brett" or, in some publications, by the species names Dekkera intermedia and Brettanomyces intermedius (3), Brettanomyces lambicus (3), Brettanomyces custersii, or Dekkera bruxellensis (6). Today, only D. bruxellensis is an accepted species name, and the other names are considered synonyms.Peptide nucleic acid (PNA) molecules are pseudopeptides which are able to hybridize to complementary nucleic acid targets (RNA and DNA) obeying Watson-Crick base pairing rules (2, 10). Due to their uncharged, neutral backbone, PNA probes exhibit favorable hybridization characteristics, such as high specificity, strong affinity, and rapid kinetics resulting in improved hybridization to highly structured targets, such as rRNA (13). In addition, the relatively hydrophobic character of PNAs compared to DNA oligonucleotides makes PNA probes capable of penetrating the hydrophobic cell wall following mild fixation conditions that do not lead to disruption of cell morphology (14). These unique characteristics of PNA have opened new possibilities for molecular diagnostic assays.The D1-D2 region of 26S ribosomal DNA (rDNA) of eucaryotic organisms shows a high degree of species variation and has been used for identification and taxonomy of yeast species (1,8). In this study, 26S rDNA sequence information was used to design speci...

The maternal messenger RNA An3 was originally identified localized to the animal hemisphere of Xenopus laevis oocytes, eggs and early embryos. Xenopus embryos depend on mRNA and protein present in the egg before fertilization (maternal molecules) to provide the information needed for early development. Localization of maternal mRNA gives cells derived from different regions of the egg distinctive capacities for protein synthesis. We show here that An3 mRNA encodes a protein with 74% identity to a protein encoded by the testes-specific mRNA PL10 found in mouse, which is proposed to have RNA helicase activity. Because the gene encoding An3 mRNA is reactivated after gastrulation and remains active throughout embryogenesis, we have examined its distribution in embryonic and adult tissues. Unlike PL10 mRNA, which is primarily restricted to the testes, An3 mRNA is broadly distributed in later development.

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