Interferon inhibits DNA Synthesis induced in Mouse Lymphocyte Suspensions by Phytohaemagglutinin or by Allogeneic Cells

IN addition to its well known antiviral activity, interferon has recently been shown to inhibit the multiplication of tumour and mammalian cells in cell culture^1–6. We report here the inhibition by interferon of DNA synthesis induced in mouse spleen lymphocytes by the non-viral stimuli phytohaemagglutinin (PHA) and allogeneic lymphocytes. These findings are in accord with our contention that interferon affects cell function and, furthermore, they suggest that by acting on lymphocytes, interferon plays a role in the immunological response of the host.     

Adventitious Root Formation in Veronica Spp.

Species of the genus Veronica differ in habitat preferences,growth form and in adventitious root production. The annualspecies rarely or never produce adventitious roots in intactplants in the field but some, for example V. persica and V.arvensis will root vigorously from single node stem segmentsin culture. Others, such as V. agrestis require the presenceof IAA for substantial levels of root formation to occur incultured stem segments. Veronica hederifolia cuttings rarelyproduce roots. Stem cuttings of the perennial species, in general,rooted more vigorously than those of annual plants. Both V.fihiformis and V. serpyllifolia root very strongly. The position of root production from the stem cuttings differedfrom species to species. Roots arose either from the node, theregion of the base or at some intermediate point. Veronica arvensis,V. chamaedrys and V. persica rooted mainly from the basal regionwhereas V. filiformis rooted mainly from the node. Veronicaserpyllifolia cuttings rooted at both of these locations. Veronica filiformis, a perennial species that is infertile inBritain, produces root primordia in intact plants at nodes whichare close to the shoot apex. Thus, even very young stem segmentshave ‘preformed’ root primordia. For this reason,detached stem segments of V. filiformis root very rapidly andthis probably has been of great significance in its successfulinvasion and spread in lawns and short turf areas. Veronica spp., adventitious roots, indol-3-ylacetic acid, root primordia, vegetative reproduction     

The food of suburban foxes (Vulpes vulpes), with special reference to London

The food of foxes in suburban London was examined using stomach contents and den litter analysis. A great diversity of food was taken. Adult foxes killed nearer to the city centre were found to eat significantly fewer earthworms, domestic pets and wild mammals, but more scavenged food items, than foxes killed closer to the suburban fringe. Cubs killed closer to the city centre ate significantly fewer earthworms and insects, and more pet birds, pet mammals and scavenged food items than cubs killed nearer the periphery of the suburban area. Although seasonal trends in food selection were apparent, they were not as pronounced as those observed in studies of rural foxes. At no time of the year did a single food item predominate in the diet of adult foxes. Passeriformes were the most important single food item in the diet of young cubs, but there was no correlation between the number of Passeriformes eaten and their abundance, nor between annual changes in the abundance of small birds and mean fox birth litter size and productivity. Most foxes examined were in good body condition; there was no seasonal variation in body weight, although fat content did vary seasonally. A complementary survey in Bristol on losses of domestic pets to foxes revealed that 07% of pet cats and 80% of other pets kept outdoors were killed in a year. Damage to garden Crops was negligible.     

Effect of Conditioned Media from Several Cell Types on Invasion by Eimeria adenoeides Sporozoites1

ABSTRACT. The effect of conditioned media (media aspirated from a variety of cell cultures after 4 d of growth) on cellular invasion by sporozoites of the turkey coccidium, Eimeria adenoeides, was examined. Conditioned medium from turkey kidney cells and baby hamster kidney cells failed to alter invasion. However, conditioned medium from turkey cecal cell cultures produced a significant (P ≤ 0.05), two-fold increase in invasion over control medium in a variety of cell types. Retentates of conditioned medium from the turkey cecal cells that were passed through microconcentrators having molecular mass cutoffs of 50, 100, and 300 kDa similarly enhanced invasion over retentates from control medium. However, retentates from microconcentrators with a cutoff of 1,000 kDa failed to enhance invasion. Pretreatment in conditioned medium, followed by washing of sporozoites prior to inoculation into cultures, did not result in enhanced invasion. Moreover, when the interval between inoculation of sporozoites into cells and fixation of cultures was reduced to less than 3 h, no enhancement of invasion occurred. Conditioned medium from turkey cecal cells that were grown in the presence of ³⁵S-translabel had at least two labeled bands at 150 kDa and > 200 kDa that were absent in conditioned media from turkey kidney and baby hamster kidney cells.     

Immunoparasitology in Avian Species

There has been no work on the immunological response of birdsto helminth infections since the late 1960s, an area of investigationthat has been too long ignored. Similarly, studies of arthropod-mediatedresponses in birds are lacking except for a few scattered investigations.Recently, a serum antibody response has been seen against onearthropod, the northern fowl mite. The appearance of antibodiesrecognizing an 8–10 kilodalton mite antigen seems to correlatewith a reduction in the mite population on infested chickens.Most of the studies on parasite immunity in avian species havecentered on the economically important Eimeria species, protozoanparasites that infect the intestine of chickens and turkeys.These investigations encompass wide areas of interest includingthe effect of immunity on parasite invasion, development ofT-cell proliferation assays and T-cell clones, inhibition ofparasite penetration and development by hybridoma antibody treatment,production of genetically engineered Eimeria antigens used inbird immunization studies, and studies using inbred or congeniclines of birds to determine what effect the major histocompatibilitycomplex has on parasite immunity. From these efforts it hasbeen learned that not only is the immunity species-specific,but also depending on where in the intestine the parasite invades,penetration is either not affected or inhibited by as much as50%. The T-cell proliferation assays suggest that this specificitymay be due to a species-specific T-cell response. Immunizationstudies using a genetically engineered antigen have indicatedthat at least partial protection against one species of Eimeriais possible. Studies done with the inbred congenic lines ofbirds have shown that the genetic makeup of the bird is importantin how it responds to either a natural infection or to immunizationwith a genetically engineered antigen. Clearly, these resultsshow not only the complexity of the bird response to parasiteinfection, but also the amount of work still undone.     

Sociality in the phylogenetically basal allodapine bee genus Macrogalea (Apidae: Xylocopinae): implications for social evolution in the tribe Allodapini

Recent phylogenetic studies based on DNA sequence data indicate that the tropical African bee genus Macrogalea is the sister group to the remaining extant allodapine fauna, whereas previously it was thought to be a distal group. This leads to some fundamental changes in our understanding of social evolution in the allodapines. Earlier studies suggested that Macrogalea showed only weak forms of social behaviour and these were not well characterized. However, large samples of Macrogalea zanzibarica presented here show that this species exhibits marked social behaviour. Nearly half of nests collected contained two or more adult females, with up to 10 females per nest. Brood are reared progressively and brood ages within colonies are staggered, giving rise to colonies with very mixed age structures and therefore frequent opportunities for alloparental care. Ovarian dissections indicate non‐simple forms of reproductive partitioning within colonies and most multi‐female colonies show evidence that more than one female has contributed to egg production, though reproductive episodes among colony members are frequently asynchronous. Some females show signs of much higher wing wear than their nestmates, but always show signs of previous reproduction. Reproductive division of labour appears to be temporally marked, ovarian differentiation among nestmates is linked to relative body size, but permanent worker‐like or queen‐like castes appear to be absent. This is similar to the communal, continuously brooded and multivoltine behaviour of some tropical halictine species and may be due to the aseasonal nature of brood development in tropical regions. Patterns of per capita brood production indicate large benefits to multi‐female nest occupancy, and sex allocation is strongly female biased. These findings strongly suggest that the capacity for complex social interactions and alloparental care is an ancestral trait for all of the extant allodapine lineages. Therefore comparisons among extant allodapines are unlikely to throw light on the initial origin of social behaviour, though they may uncover origins of true caste behaviour and reversals to solitary nesting. Sex ratios in Macrogalea and most other allodapine genera, spanning a broad phylogenetic and ecological range, suggest that one or more allodapine traits have provided persistent selection for female‐biased sex allocation.