Development of ecology in Japan,with special reference to the role of Kinji Imanishi

The development of ecology in Japan, especially after the Meiji Restoration (1868), is briefly reviewed. Pioneering studies of Hiratsuka, on the calorimetric budget of a silkworm population, and Motomura, on the relation between numbers of species and individuals in biotic communities, are noteworthy. A critical examination of his role in ecology in Japan reveals Kinji Imanishi to have played pivotal roles in leading Japanese population ecologists to realize the importance of dispersal in population regulation, and leading to the worldwide revival of field primatology. Although Imanishi's later (popular) writings, in which he completely negated the role of competion and natural selection, have justifiably drawn much criticism, his earlier critique of the competition-Almighty paradigms may be re-evaluated in the light of recent discussions on interspecific competition and community equilibrium.     

On the role of tubificid oligochaetes in relation to fish disease with special reference to the myxozoa

Whirling disease is caused by the myxozoan parasite Myxobolus cerebralis, Hofer. It has been associated with a serious decline in wild rainbow trout populations in the western United States. The alternate host is the tubificid oligochaete Tubifex tubifex, and perhaps other tubificids. Tubifex is a very adaptable taxon, being found in various morphological forms. Polyploidy has been demonstrated. There is some suspicion that sibling species may be found to exist. Infection rates in tubificids are low. Related myxosporeans are associated with a variety of aquatic oligochaete worms belonging to three families, Tubificidae, Naididae and Lumbriculidae, and also with polychaetes. Myxozoans are now recognized as members of the phylum Cnidaria. Other fish parasites, such as the cestodes Archigetes and Caryophyllaeus and the nematode Eustrongylides, are transmitted by tubificids. The tubificid worm population in an ecosystem may provide an infective reservoir as the disease persists for long periods in the worm. Control of worm populations might be achieved by reducing organic inputs, lowering erosion, increasing flow and removing objects that accumulate pockets of silt. The use of pesticides is unlikely to be effective because of a lack of specific impact and consequent disruption of the whole benthic community, at least.     

Ecology of siderophores with special reference to the fungi

Ecology of siderophores, as described in the present review, analyzes the factors that allow the production and function of siderophores under various environmental conditions. Microorganisms that excrete siderophores are able to grow in natural low-iron environments by extracting residual iron from insoluble iron hydroxides, protein-bound iron or from other iron chelates. Compared to the predominantly mobile bacteria, the fungi represent mostly immobile microorganisms that rely on local nutrient concentrations. Feeding the immobile is a general strategy of fungi and plants, which depend on the local nutrient resources. This also applies to iron nutrition, which can be improved by excretion of siderophores. Most fungi produce a variety of different siderophores, which cover a wide range of physico-chemical properties in order to overcome adverse local conditions of iron solubility. Resource zones will be temporally and spatially dynamic which eventually results in conidiospore production, transport to new places and outgrow of mycelia from conidiospores. Typically, extracellular and intracellular siderophores exist in fungi which function either in transport or storage of ferric iron. Consequently, extracelluar and intracellular reduction of siderophores may occur depending on the fungal strain, although in most fungi transport of the intact siderophore iron complex has been observed. Regulation of siderophore biosynthesis is essential in fungi and allows an economic use of siderophores and metabolic resources. Finally, the chemical stability of fungal siderophores is an important aspect of microbial life in soil and in the rhizosphere. Thus, insolubility of iron in the environment is counteracted by dissolution and chelation through organic acids and siderophores by various fungi.     

A cytogenetic study of mentally retarded school children in taiwan with special reference to the fragile X chromosome

Summary A cytogenetic study was made on 341 mentally retarded children in the Provincial Nantou Rehabilitation Center for the Mentally Retarded and the St. Raphael Opportunity Center in Tainan. Of the 89 mentally retarded children with chromosomal abnormalities, 63 had Down syndrome, 13 had the fragile X [fra(X)] syndrome, and the remaining had other aneuploid constitutions. Family studies were possible for 2 of the 13 fra(X) probands. The results of this study illustrate the contribution of chromosomal abnormalities to the pathogenesis of mental retardation in children.     

Biomechanical aspects of underwater acoustics with a special reference to hydrobiology

Some biomechanical aspects of the acoustical behaviour of underwater animals is discussed here. We have avoided mathematical complexities.     

An aetiological study of 290 XXY males,with special reference to the role of paternal age

Summary Data on 290 non-mosaic 47,XXY males have been analysed for possible associations with parental ages at birth, season of birth, sex ratio among sibs, and twinning. Comparison with matched population controls revealed a highly significant association with parental age, which was fully explained by dependence on maternal age and maternal age alone. The maternal age effect was determined with greater precision than in an earlier study of the same material, in which siblings were used as controls, and was estimated to result in an increased risk of between 5% and 10% per annum (p.a.). The estimated independent effect of paternal age, after fitting maternal age, was marginally (but not significantly) negative, and excluded an increased risk in excess of 3% p.a. Paternal age therefore appears to have little if any independent significance in the aetiology of 47,XXY. After correcting for seasonal variations in the population birth rate and smoothing, there was a peak of XXY births in March and a trough in November. Though not statistically significant, the pattern resembled that reported in previous studies, and was similar for both younger and older mothers. The twinning rate for both the XXYs and their sibs, and the sex ratio among the latter, were close to the corresponding population values.     

Cryopreservation of bacteria with special reference to anaerobes

The author is with the DSM-Deutsche Sammlung von Mikroorganismen und Zellkulturen GmbH, Mascheroder Weg 1b, D-3300 Braunschweig, Germany.