Ultrastructure of rabbit lung intravenously infected with Mycobacterium simiae "Weiszfeiler" no 52.

M. simiae "Weiszfeiler" strain No. 52 belongs to the second Runyon Group of Atypical Mycobacteria characterized by rough, eugonic, yellow-orange pellicle grown on Sauton medium incubated for 14 days at 37 degrees C. A suspension containing 10 mg/ml (equalling 5 times 10-7 viable units) injected intraveneously into rabbits provokes profound changes in the ultrastructure of the pulmonary tissue, manifested in activation of macrophages and pathologic alteration of pneumocytes. In histologic sections stained according to the Ziehl-Neelsen technique and examined in a light-microscope cytoplasmic acid-fast, highly dispersed granules are found in macrophages, resembling in morphological appearance the cellular phospholipids in sarcoid granuloma. Abundant production of interalveolar and interseptal fibrotic collagen tissue was observed in rabbits infected with M. Simiae a rather striking phenomenon in fresh experimental mycobacterial infection in the rabbit. The strain in question should therefore be considered not as Saprophyte but as a Mycobacterium Species with attenuated virulence, closely related to Prissic and Masson's M. scrophulaceum.     

Thermal variation near the thermal optimum does not affect the growth,metabolism or swimming performance in wild Atlantic salmon Salmo salar

Typically, laboratory studies on the physiological effects of temperature are conducted using stable acclimation temperatures. Nonetheless, information extrapolated from these studies may not accurately represent wild populations living in thermally variable environments. The aim of this study was to compare the growth rate, metabolism and swimming performance of wild Atlantic salmon exposed to cycling temperatures, 16–21°C, and stable acclimation temperatures, 16, 18.5, 21°C. Growth rate, metabolic rate, swimming performance and anaerobic metabolites did not change among acclimation groups, suggesting that within Atlantic salmon's thermal optimum range, temperature variation has no effect on these physiological properties.     

Molecular basis of ion permeability in a voltage‐gated sodium channel

Voltage‐gated sodium channels are essential for electrical signalling across cell membranes. They exhibit strong selectivities for sodium ions over other cations, enabling the finely tuned cascade of events associated with action potentials. This paper describes the ion permeability characteristics and the crystal structure of a prokaryotic sodium channel, showing for the first time the detailed locations of sodium ions in the selectivity filter of a sodium channel. Electrostatic calculations based on the structure are consistent with the relative cation permeability ratios (Na⁺ ≈ Li⁺ ≫ K⁺, Ca²⁺, Mg²⁺) measured for these channels. In an E178D selectivity filter mutant constructed to have altered ion selectivities, the sodium ion binding site nearest the extracellular side is missing. Unlike potassium ions in potassium channels, the sodium ions in these channels appear to be hydrated and are associated with side chains of the selectivity filter residues, rather than polypeptide backbones.     

563. PASSIFLORA LONGICUSPIS

Summary.  Passiflora longicuspis (Passifloraceae), a new, red, large-flowered species of Passiflora from French Guiana is described; its history, taxonomy, distribution, pollination ecology and cultivation are discussed.     

Conservation challenges in a threatened hotspot: agriculture and plant biodiversity losses in Baja California,Mexico

Modern agricultural practices pose serious threats to biodiversity worldwide. Species losses from habitat conversion are well documented, but indirect impacts such as reduced water availability to adjacent ecosystems are less known. San Quintín is an important agricultural valley in the mediterranean climate region of Baja California, Mexico. The region is also a hotspot of plant species richness and endemism. Plant species in the region are here analyzed by comparison of the contemporary flora to historical botanical collections to identify extirpations. Historical collections indicate that habitat loss to agriculture has been a direct cause of species losses. As importantly, the unsustainable extraction of groundwater has apparently led to salt water intrusion, resulting in the loss of 22 native plant taxa, including 13 rare plants. Seventy-eight percent of all the vernal pool taxa have been lost from the flora (including 85 % of the rare taxa) and 11 % of plants of riparian and pond habitat (including 25 % of the rare taxa) are no longer found in the region. Unsustainable agricultural practices continue to threaten fragile coastal ecosystems and are a serious challenge to current and future conservation efforts. Ironically, these same practices frequently result in abandonment of cultivated areas. Owing to indirect impacts, conservation of biodiversity and large-scale agricultural operations are even less compatible on a regional scale than indicated by direct impacts. It is vital that sustainable agricultural practices be adopted locally and globally to avoid further losses of biodiversity.     

Where to conserve? Plant biodiversity and endemism in mediterranean Mexico

Six regions of northwestern (NW) Baja California (Sierra de Juárez, Sierra de San Pedro Mártir, Punta Banda, Colonet, San Quintín and Valle Tranquilo) were compared for their floristic diversity. Checklists for each region were analyzed by their total, native, and endemic floras to give measures of floristic similarity and overlap, and to identify the strongest gradients affecting species distributions. Each region was floristically distinct, with significant variation in the distribution of state endemic taxa. The six regions are readily differentiated by their geographical position in a Principal Components Analysis. The strongest gradients were (a) the W–E gradient from the coast to the mountains and (b) the latitudinal gradient from N to S. These six adjacent regions are found within a local and global biodiversity hotspot that is subject to intense conservation challenges. Conservation of many areas is essential to adequately preserve the diversity of locally endemic taxa with restricted ranges, yet the coast lacks any protected areas at the state and federal level. Private reserves such as Reserva Natural San Quintín may be critical to the conservation of regionally endemic taxa.     

Wing morph-related physiological differences in adults of temperate population of Pyrrhocoris apterus (L.) (Heteroptera: Pyrrhocoridae)

The reproductive and diapausing adult females of brachypterous morph and macropterous females with reproductive arrest of non-diapause type, originating from the laboratory cultures of Pyrrhocoris apterus, were studied for their feeding and drinking behaviour, digestive enzyme activities, and carbohydrate and lipid contents. The highest feeding and drinking activities were observed in reproductive brachypters, the lowest in macropters. Macropters also differed from brachypters by lower activities of gut lipase, peptidase and protease, lower concentration of haemolymph sugars, and lower weight of fat body, which probably reflects their low feeding activity. The total content of fat body lipids was also lower in macropters (0.6 mg) than in reproductive and diapausing brachypters (4.6 and 7.5 mg, respectively) on day 14. A very high amount of glycogen was found in the fat body of diapausing brachypters, 363 micrograms on day 14, as opposed to 15 and 80 micrograms in macropterous and reproductive brachypterous females, respectively. The obtained data indicate that the most important difference between macropterous and brachypterous females with different types of reproductive arrest consists of an enhanced mobilization of lipids for dispersal in macropters and accumulation of energetic reserves for hibernation in brachypters.     

Self-inoculation with Mycobacterium tuberculosis Weiszfeiler W-115.

After intracutaneous self-inoculation with 0.05 mg (wet weight) of Mycobacterium tuberculosis W-115 containing approximately 600 000 viable units, the local reaction was observed during a period of 9 weeks. No adverse effects or general reaction were observed. From the lesion the W-115 strain was recultivated. It was labelled W-115(78)ST vaccine strain and is used for further studies. On the basis of experiments on laboratory animals, monkeys, human new-borns and adults, the strain W-115 is considered as safe for antituberculous vaccination as the strains Mycobacterium bovis BCG and the attenuated "MP" strain of Mycobacterium microti OV 166.