Development of Haemogregarina boueti in the toad Bufo regularis*

SYNOPSIS. Haemogregarina boueti França, 1910, was found to be the commonest blood parasite in the common toad, Bufo regularis Reuss, in Egypt. The rate of infection was about 30% (of 689 toads examined). In properly fixed blood films, the parasites were almost exclusively intraerythrocytic. Most characteristic was the encapsulated “elongate” form averaging 22.3 by 6 μ with a more-or-less central nucleus and a pointed, slightly bent, posterior end. Infected red cells were conspicuously hypertrophied and their nuclei were markedly displaced and frequently broken into 2-4 parts. Young and growing blood forms as well as two types of hepatic schizonts are described for the first time. Schizonts of the first type develop in hepatic cells, are 28–30 μ in diameter and produce numerous elongate oval merozoites about 8 × 2.2 μ radially arranged around a residual body about 10 μ in diameter. Schizonts of the second type start their growth in erythrocytes but later complete their development as free bodies in the liver sinusoids. When mature, they are 32–35 μ in diameter and produce a larger number of thin merozoites about 8 × 1.5 μ, surrounding a larger residual body about 19 μ in diameter.     

Haemogregarina faiyumensis n. sp. in the Toad Bufo regularis in Egypt*

SYNOPSIS. Haemogregarina faiyumensis n. sp., a parasite of toads, Bufo regularis, in Faiyuni Province, Egypt, U.A.R., is described. In a survey of 689 toads from various localities in Cairo, Giza and Faiyurn provinces, only 3 out of 13 toads from Kom O Shim near Faiyum were infected. This species, known only by blood forms (most probably gametocytes) of two different staining reactions, is 13-17 μ long and 4-5 μ wide, with an average of 15.5 × 4.5 μ. The nucleus is typically subcircular and 3-5 × 3–5 μ, with an average of 4.5 × 3.9 μ.     

Interaction between Fusarium oxysporum F. vasinfectum and Cephalosporium maydis on cotton and maize

The interaction between Fusarium oxysporum (cause of cotton wilt) and Cephalosporium maydis (cause of maize late-wilt) on cotton roots is associated with an appreciable decrease in the severity of the cotton wilt disease. Reduction in infection is more pronounced when the latter fungus precedes the former in the soil than when they are inoculated simultaneously. C. maydis exerts little or no such effect when it follows F. oxysporum in the soil. C. maydis grows on the surface of cotton roots near growing points as a root-surface inhabitant. Dark red lesions are produced but these disappear, as does the fungus, when the root becomes hardened either naturally or in response to the growth of the fungus on the surface. The presence of the fungus is associated with increased production of root laterals. Cotton plants, including those which may appear healthy, show only mild internal symptoms of Fusarium infection when grown in soil inoculated with the two fungi, suggesting that the decreased severity of wilt is largely due to increased tolerance of the plants to infection with the disease as a result of increased number of root laterals. It is also possible that cotton roots with C. maydis on their surface become less suitable for the progress of F. oxysporum. F. oxysporum produces in culture a metabolite inhibitory to C. maydis. This may partly account for the little effect that the latter fungus exerts on the severity of wilt when it follows F. oxysporum in the soil. It appears that the interaction between F. oxysporum and C. maydis does not affect the pathogenicity of the latter fungus to maize.     

Audit of 6 years' experience of breast fine needle aspiration (FNA) cytology using the cytospin method; improvement through multidisciplinary clinical audit

Audit of 6 years' experience of breast fine needle aspiration (FNA) cytology using the cytospin method; improvement through multidisciplinary clinical audit
A breast FNA cytology service for palpable breast lumps was commenced in 1989 using the cytospin method. Over the following 6 years 2314 aspirates were received. The results were audited in detail in 1990, 1991/1992 and 1994. Multidisciplinary clinical audit meetings followed each audit cycle. Practice change was agreed after each audit. Each audit cycle was followed by demonstrable improvement in the complete sensitivity of the technique, being respectively 79%, 88% and 96%. The cytospin method is a viable alternative to the conventional smear method.     

Pathogenic behaviour of Cephalosporium maydis and C. acremonium

Cephalosporium maydis infects young maize plants easily, but as plants age fewer are infected and none after approx. 50 days from sowing. The mesocotyl and seminal, fibrous and adventitious roots are attacked, especially when there is damage or much inoculum. Most penetration occurs where roots are elongating and emerge from the mesocotyl or from fibrous roots. At first the fungus grows superficially on roots, producing hyphae with short, brown, thick-walled, and swollen cells. After penetrating, the fungus spreads towards the xylem, where it grows slowly at first but after 5 weeks grows faster upwards.
C. acremonium causes black-bundle disease of maize. It seems to infect plants growing in unfavourable conditions but the details remain uncertain. The percentage of plants infected was not related to the amount of inoculum and the fungus may not be a primary parasite. The sterile culture filtrate of the fungus produces vascular discoloration and wilt of maize seedlings.     

Rhythmic Growth Rings of Wood and Their Relationship with the Foliage in Oak Seedlings Grown in a Favourable Environment

The anatomy of wood was studied inQuercus roburL. andQuercussuberL. seedlings exhibiting 3–8 units of extension, eachwith a tier of photosynthesizing leaves in their upper parts,generated as the result of rhythmic shoot growth under favourableconditions. At all the axis levels examined (i.e. the base ofeach of the different units of extension, four other equidistantlevels within the first unit of extension and the upper partof the taproot), the wood displayed rings when treated withWiesner reagents. This indicated cinnamaldehyde groups presentin lignins. No rings appeared when the Maüle reaction wasused for specific detection of syringyl subunits in lignins.A trend towards a periodical arrangement of xylem parenchymabands was also found when sections were treated with I₂/KI.The number of rings coincided with the number of leaf tiersabove the level of measurement, and did not vary inside thefirst unit of extension. Thus, the rings are called rhythmicgrowth rings. In sections of the first and the second unitsof extension, and in the taproot, the area and width of a givenrhythmic growth ring were highly correlated with the total areaof leaves present above the level of measurement at the presumedtime of growth ring formation. Moreover, stem diameter at thebase of the units of extension was highly correlated with theleaf area above. These results indicate that differentiationof xylem, particularly its lignification, varies rhythmicallyin oak seedlings. They imply that wood production is linkedto the photosynthesizing and/or transpiring area of the plant.Thus, during a growth cycle ofQ. roburandQ. suberseedlings,there appears to be integration of the primary metabolic activitieswith the laying down of rhythmic growth rings.Copyright 1998Annals of Botany Company Allometric relationship, juvenile wood, leaf area, lignification, oak seedling, periodic structure,Quercus roburL.,Quercus suberL., rhythmic growth ring, unit of extension.