Molecular Assays for Detecting Aphanomyces invadans in Ulcerative Mycotic Fish Lesions

The pathogenic oomycete Aphanomyces invadans is the primary etiological agent in ulcerative mycosis, an ulcerative skin disease caused by a fungus-like agent of wild and cultured fish. We developed sensitive PCR and fluorescent peptide nucleic acid in situ hybridization (FISH) assays to detect A. invadans. Laboratory-challenged killifish (Fundulus heteroclitus) were first tested to optimize and validate the assays. Skin ulcers of Atlantic menhaden (Brevoortia tyrannus) from populations found in the Pamlico and Neuse River estuaries in North Carolina were then surveyed. Results from both assays indicated that all of the lesioned menhaden (n = 50) collected in September 2004 were positive for A. invadans. Neither the FISH assay nor the PCR assay cross-reacted with other closely related oomycetes. These results provided strong evidence that A. invadans is the primary oomycete pathogen in ulcerative mycosis and demonstrated the utility of the assays. The FISH assay is the first molecular assay to provide unambiguous visual confirmation that hyphae in the ulcerated lesions were exclusively A. invadans.     

CRYPTOPERIDINIOPSIS BRODYI GEN. ET SP. NOV. (DINOPHYCEAE), A SMALL LIGHTLY ARMORED DINOFLAGELLATE IN THE PFIESTERIACEAE1

A new genus and species of heterotrophic dinoflagellate, Cryptoperidiniopsis brodyi gen. et sp. nov., are described. This new species commonly occurs in estuaries from Florida to Maryland, and is often associated with Pfiesteria piscicida Steidinger et Burkholder, Pseudopfiesteria shumwayae (Glasgow et Burkholder) Litaker et al., and Karlodinium veneficum (Ballantine) J. Larsen, as well as other small (<20 μm) heterotrophic and mixotrophic dinoflagellates. C. brodyi gen. et sp. nov. feeds myzocytotically on pigmented microalgae and other microorganisms. The genus and species have the enhanced Kofoidian plate formula of Po, cp, X, 5′, 0a, 6″, 6c, PC, 5+s, 5″′, 0p, and 2″″ and are assigned to the order Peridiniales and the family Pfiesteriaceae. Because the Pfiesteriaceae comprise small species and are difficult to differentiate by light microscopy, C. brodyi gen. et sp. nov. can be easily misidentified.     

Restricted food intake limits brown adipose tissue hypertrophy in cold exposure

Two factors that may determine brown adipose tissue (BAT) hypertrophy during conditions of increased metabolic heat production are increased food intake and increased sympathetic nervous system (SNS) activity. Since these two proceed pari passu during cold exposure, their independent contributions to BAT hypertrophy are unknown. To examine the role of each, we limited the food intake of a group of cold exposed rats by pair feeding them to warm exposed control rats and then compared the pair fed rats to ad lib fed cold exposed animals. Restricted food intake limited absolute BAT hypertrophy (0.226 +/- 0.01 g. vs 0.488 +/- 0.02 g, pair fed vs ad lib, P less than 0.01), BAT as per cent body weight (0.189 +/- 0.12 vs 0.252 +/- 0.012, P less than 0.01) and BAT protein content (34.4 +/- 3.8 vs 48.9 +/- 2.6 mg, P less than 0.01) despite evidence of quantitatively similar activation of the SNS in BAT in both groups. We conclude that increased food intake contributes to BAT hypertrophy in cold exposure independent of sympathetic activity.     

Synoptic aspects of mortality. A case study

Various localized studies have shown statistical relations between mortality, specifically mortality from cerebral vascular accidents, and meteorological fronts. A synoptic study, covering daily deaths in the United States from 16 October to 6 November, 1963, marked by the passage of a very pronounced cold front and accompanied by a complete change in weather pattern failed to show any relations of the frontal motion to either CVA mortality or general mortality.

---

Zusammenfassung Verschiedene Untersuchungen an bestimmten Orten brachten statistische Beziehungen zwischen der Sterblichkeit, besonders der bei cerebralen Blutungen und Wetterfronten. Eine synoptische Studie mit den täglichen Todesfällen in den USA vom 16 Oktober bis 3 November 1963, die durch den Durchzug einer sehr markanten Kaltfront gekennzeichnet und von einem vollständigen Wechsel im Wettergepräge begleitet war, zeigte keinerlei Beziehung zwischen dem Frontdurchzug und der allgemeinen Sterblichkeit oder der an cerebralen Blutungen.

---

Resume Diverses études localisées ont montré qu'il existe des rapports étroits, statistiquement prouvés, entre les fronts météorologiques d'une part, les décès en général et plus spécialement ceux provenant d'accidents cérébro-vasculaires d'autre part. Une étude synoptique a été faite en considérant, jour après jour, tous les décès survenus aux Etats-Unis du 16 Octobre au 6 Novembre 1963. Cette période est caractérisée par le passage d'un front froid très actif suivi d'un changement complet des conditions atmosphériques. Cette étude n'a révélé aucune relation entre le passage du dit front d'une part, les accidents cérébro-vasculaires ou les décès en général d'autre part.

     

Symmetry: A guide to its application in 2D electron crystallography

A defining property of a crystal is its symmetry. This mini-review sets out to summarize all aspects that define 2D crystallographic symmetry as applied to the study of macromolecular structure. It begins by defining molecular point symmetries, before covering crystallographic symmetry operations in 2D, common notation, a summary of crystallographic plane groups and theoretical methods and important considerations for the identification and application of symmetry in 2D crystal images for 3D structure determination. While many of the concepts covered here may be equally applicable to point symmetry and space group symmetry in 3D, this review has been written from the perspective of 2D electron crystallography and deals specifically with symmetry operations and crystallographic space groups in 2D crystal projection images.