Facultative parasites and host respiration. I. Healthy tissue adjacent to the site of infection

Summary The respiration, as measured by oxygen uptake, was higher for healthy tissue adjacent to soft rots of apple (var. Bramley) caused byPenicillium expansum Link andThom. andBotrytis cinerea Fr. and of potato tuber (var. Arran Banner) caused byErwinia aroideae Townsend, than tissue at a more distant site. The respiration of tissue adjacent to a physiological rot caused by bruising was not affected. It was concluded that there is diffusion of a substance(s) from the site of infection which causes an increase in the rate of respiration of the adjacent tissue.This work formed part of a Ph. D. thesis submitted to the University of London, July 1961.     

Studies on Central African Pans III

Summary Measurement have been recorded of alkalinity, pH, and diurnal temperature variation in twelve shallow ephemeral rain pools on aeolian Kalahari sand in Central Africa. These twelve pools were representative of many throughout the region and covered a wide range of volumes. All the pools, however, were subject to rapid temperature fluctuations on hot sunny days, from temperatures in water and mud of 20°C–25°C in the morning to 35°C–38°C (water) and 30°C–35°C (mud) in the afternoon. Where vegetation was present in larger pools and where ungulate faeces were abundant, the pools developed organic sediments which were analysed during the dry season. Organic (faecal) pollution was common in pools lying on salt lick areas frequented by game animals, and was therefore most marked in alkaline pools.Macroscopic organisms were sampled by nets and with traps, and were analysed by number and by weight. Estimates are given of population density and of standing crop biomass. The biological properties of the pools (vegetation and pollution) had a marked effect on the macrofauna, qualitatively and quantitatively. This was reflected in mechanisms of dispersal and aestivation, and in respiratory mechanisms. Three probable food chains were demonstrated. The fauna comprised a restricted number of specialised species in certain groups — particularly well represented by species numbers were Coleoptera and Hemiptera, and quantitatively tadpoles, Odonata, Conchostraca and Anostraca were important. Predators formed a high proportion of the population. Standing crop biomass was highest in polluted alkaline pools in which tadpoles and Anisops were abundant.

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Zusammenfassung Aus zwölf seichten, flachen, ephemerischen Regenlöchern im äolischen Kalaharisand in Zentral-Afrika wurden Messungen von Alkalinität, pH und Tagestemperatur-Unterschieden aufgezeichnet. Diese zwölf Tümpel sind representativ für viele der ganzen Gegend und haben ganz verschiedenen Inhalt. Alle Tümpel waren rapiden Temperatur-Fluktuationen ausgesetzt an heißen, sonnigen Tagen, von Temperaturen von Wasser und Schlamm 20–25°C morgens, bis nachmittags von 35–38°C (Wasser), 30–35°C (Schlamm). Wo in größeren Teichen Vegetation vorhanden war und wo reichlich Ungulatkot war, entwickelten sich in den Teichen organische Sedimente, welche während der Trockenzeit analysiert wurden. Organische (Kot) Verunreinigung des Wassers war allgemein üblich in Teichen die in Salz-Lecke Gegenden, überhäuft von Wild, lagen, und fiel daher am meisten in alkalischen Teichen auf.Proben von makroskopischen Organismen wurden mit Netzen und Fallen genommen und nach Nummer und Gewicht analysiert. Berechnungen der Bevölkerungsdichte und der Ergiebigkeit (Biomasse) sind angegeben. Die biologischen Eigenschaften der Teiche (Vegetation und Wasserverunreinigung) hatten eine auffallende Wirkung auf die Makro-Fauna, qualitativ und quantitativ. Dies reflektierte sich in ihrer Weise der Ausbreitung und Ästivation, und im Atmungsprozeß. Drei wahrscheinliche Nahrungsketten wurden vorgeführt. Die Fauna bestand aus einer beschränkten Zahl spezialisierter Arten von bestimmten Gruppen — besonders gut representiert durch Anzahl der Spezies waren Coleoptera und Hemiptera, und quantitativ bedeutend waren Kaulquappen, Odonata, Conchostraca und Anostraca. Predatoren formten eine hohe Proportion der Bevölkerung. Die Ergiebigkeit (Biomasse) war am höchsten in verunreinigten, alkalischen Teichen in welchen reichlich Kaulquappen und Anisops anwesend waren.

     

Lewis a blood group antigen of non-secretors: a receptor for candida blastospores

Abstract This study tested the hypothesis that the Lewis ^a blood group antigen found predominantly on the cells of non-secretors might be one of the receptors for Candida species. Binding of strain 3118C to epithelial cells from either secretor or non-secretor donors was not inhibited by treating the cells with anti-Lewis ^a or anti-Lewis ^b antisera. Binding of strain 3091 to non-secretor cell was inhibited by pretreating the cells with anti-Lewis ^a, but this was not observed for secretor cells.
The results suggest that Lewis ^a might be one of the receptors for some yeast strains.     

Respiratory disease and wasting in athymic mice infected with pneumonia virus of mice

Although pneumonia virus of mice (PVM) is ubiquitous among rodent colonies in the United States, it has not been reported to cause clinically apparent disease in euthymic mice. However, PVM has been reported to cause respiratory disease and death in experimentally infected euthymic and athymic mice. A group of nu/nu mice, housed in quarantine in a Trexler-type isolator, had weight loss and dyspnea. Gross necropsy findings included cachexia and diffuse pulmonary edema or lobar consolidation. Histologically there was diffuse interstitial pneumonia. Electron microscopy revealed filamentous virions budding from plasma membranes, and immunohistochemical staining of lung tissue was positive for PVM antigen. PVM was isolated from affected lung tissue in BHK 21 cells and mouse antibody production tests resulted in seroconversion to PVM. Experimental inoculation of athymic mice with lung homogenate from spontaneously infected mice resulted in clinically apparent respiratory disease and histologic lung changes similar to those in naturally infected mice. Inoculation of athymic mice with infected BHK 21 cell culture fluid resulted in pneumonia which was qualitatively similar to, but less severe than, that observed in mice with spontaneous disease. These findings indicate that naturally occurring PVM infection in athymic mice may cause respiratory disease and wasting.