Orchid mycorrhiza probably affects about 25 000 plant species and thus roughly one tenth of all higher plants.Histologically, this symbiosis resembles other kinds of endomycorrhiza, the fungal hyphae growing within living plant cells. Considerable evidence, however, suggests that it is not a two-way exchange relationship and thus not potentially mutualistic, such as the wide-spread endomycorrhiza between plants and Glomalean fungi, known as arbuscular mycorrhiza. During the achlorophyllous seedling stage orchids are obligately dependent on the fungi; some species remain so through life, while others establish photosynthesis but to varying degrees remain facultatively dependent of / responsive to fungal infection as adults. None of the fungi involved are so far known to depend on the symbiosis with orchids. Transfer of organic carbon compounds from hyphae to the orchid has been demonstrated repeatedly, but it is not clear to what extent this takes place during a biotrophic phase while the intracellular hyphae remain intact, or during the subsequent extensive degradation of the hyphal coils. The advantage of viewing orchid mycorrhiza basically as a unilateral mycophagous relationship, in spite of hypothetical beneficial spin-offs to the mycobiont, is that it provides a conceptual framework similar to that of other parasitic or fungivore relationships; mechanisms known in such relationships could be searched for in future studies of the orchidÁfungus symbiosis. These could include mechanisms for recognition, attraction and selection of fungi, physiological regulation of internal hyphal growth, breakdown, and material transfer, nutritional consequences of the plant's preference(s) and trophic changes, fungal avoidance mechanisms, and consequences at population and ecosystem levels. A whole range of possible life strategies becomes apparent that could support divergent evolution and lead to the proliferation of species that has indeed occurred in the orchid family. We outline some of the possible physiological mechanisms and ecological implications of this approach.

A cladistic analysis of Orchidaceae was undertaken for 98 genera using 71 morphological apomorphies based on a reconsideration of previous character analyses and newly discovered variation. The equally weighted analysis found 60 000 most parsimonious trees with low consistency (CI = 0.29) but high retention (RI = 0.83). The strict consensus reveals a significant amount of structure, and most traditionally recognized subfamilies are supported as monophyletic, including the Apostasioideae, Cypripedioideae, Spiranthoideae, and Epidendroideae. Orchidoideae in the broad sense are paraphyletic, giving rise to spiranthoids. Vanilloids are sister to epidendroids, although exhibiting several states otherwise found only in clearly basal groups, such as Apostasioideae. The nonvandoid epidendroids are poorly resolved, due to a high degree of homoplasy. The vandoids appear to be monophyletic, contrary to recent molecular evidence, possibly due to repeated parallel development of the vandoid character suite. The importance of vegetative characters as evidence putatively independent from floral features is demonstrated in the placement of Tropidia. Implied weighting analysis of these data resulted in similar patterns at high levels, although the Orchidoideae and Spiranthoideae may each be monophyletic and the nonvandoid epidendroids are more resolved. The high degree of structure implied in previous orchid classifications must be reconsidered, given the poor resolution at lower levels in the present trees.

The aims of the study are to analyse Swedish trends in overweight and obesity-as measured by body mass index (BMI)-between 1971 and 1995, and to examine socioeconomic and geographic differences between groups of individuals on the basis of information on 18-y-old military conscripts. The study population comprises all males born in 1953, 1958, 1963, 1968, and between 1973 and 1977, reported to be living in Sweden at 17 y of age according to nationwide population registers (RTPs). Utilizing the unique personal ID number, sociodemographic data in the RTPs and in Population and Housing censuses were linked to data on BMI in the national Military Service Conscription Registry for the years 1971 to 1995. These data were obtained from compulsory medical examinations held at military induction at 18 y of age. BMI data were available for 448 732 (89%) of a total of 503 689 subjects. Mean BMI increased by 6.6% over the study period-from 21.1 kg/m2 in 1971 to 22.4 kg/m2 in 1995. Unadjusted trend analyses showed a 2.4 times increase in the prevalence of overweight among 18-y-old males over the period-from 6.9% in 1971 to 16.3% in 1995. Over the same years, the prevalence of obesity increased 3.5 times-from 0.9% to 3.2%. After adjustment for muscle power, demographic factors, and living area, the prevalence of overweight was found to have increased 1.4 times, and obesity 1.7 times between 1971 and 1993. The prevalence of overweight was considerably higher among 18-y-old males from low-educated families than among those from high-educated families in both 1971 and 1995. The prevalence of overweight was also found to be higher in both 1971 and 1995 among young men from rural and/or sparsely populated areas than among those living in Sweden's largest cities. Mean BMI, and the prevalence of overweight and obesity have increased among 18-y-old males in Sweden over the last 24 y. The increased risk of overweight among young men from low-educated families and those from rural and/or sparsely populated areas detected in 1971 was still evident in 1995.

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Recent phylogenetic analyses confirm the monophyly of Orchidaceae as sister group to the remainder of Asparagales, and identify the sequence of early branching lineages in Orchidaceae. Orchid seedling mycorrhiza (OSM) involving rhizoctonious fungi is distributed widely in all subfamilies, including the first branching ones, and its status as a founding event is thus supported. OSM is recognized as one element in the character syndrome that distinguishes orchid biology, and we argue that OSM was the first to evolve. We also discuss the possible evolutionary origins of OSM in Asparagales. The prevalent mycobionts suggest a derivation from a pathogenic relationship, and sister group comparison offers little support for derivation from other mycorrhizal relationships. A combination of in situ sowings and molecular identification of seedling mycobionts has established that a broad range of fungi besides rhizoctonious mycelia are presently involved in OSM, presumably evolving secondarily and often in parallel in different orchid clades. Structural features and internal patterns of mycobiont behaviour appear to have remained largely the same, implying that OSM needs only minor physiological adjustment to accommodate new mycobionts. Such modifications will have involved checkpoints for recognition/rejection and the formation/ breakdown of pelotons. These physiological mechanisms are so far largely unknown. The trophic versatility of the mycobionts and the apparently easy shifts could be a main factor in the ecological adaptability of orchids and proliferation of the family.

In crossover trials, four lactating goats were given intramammary infusions and intramuscular injections of radioactivelabeled benzylpenicillin, spiramycin, chloramphenicol, dihydrostreptomycin, and tetracycline. Milk was collected after each treatment and the antibiotic contents in whole milk, skim milk, and whey were determined microbiologically and radiochemically and in cream and casein by radiochemical assay methods. Uptake of antibiotics by cream and casein was highly dependent on drug concentration, increasing with the decrease in antibiotic content in whole milk. Lipophilic chloramphenicol and tetracycline were concentrated in cream to a higher degree than the less lipophilic benzylpenicillin and dihydrostreptomycin. Antibiotic uptake by cream separated from whole milk after intramuscular injection was higher than after intramammary infusion. Antibiotic uptake by casein was independent of the route of administration and was highest for dihydrostreptomycin and tetracycline and lowest for benzylpenicillin.

Abstract:The sectile state, in which pollinia are subdivided into units larger than tetrads, is one of several systematically important orchid pollinium characters. We recognize two types of sectile pollinia, based upon form and arrangement of massulae. One type is found primarily in members of Orchidoideae-Spiranthoideae, while the other characterizes epidendroid genera. Additional characters that have systematic potential are massula dimorphism, caudicle composition, and degree of tetrad packing. Hollow sectile pollinia unite Arethusa and CaIopogon; Stereosandra and Epipogium have dissimilar pollina, but other characters support a close relationship between them. The sectile condition is interpreted as resulting from a shift in the timing of cohesion of developing pollen cells.

Rasumussen, F., 1978.Tissue damage at the injection site after intramuscular injection of drugs.Vet. Sci. Commun.,2: 173-182.