COLI-AEROGENES BACTERIA FROM FARM DAIRY EQUIPMENT AND RAW MILK

SUMMARY: A series of 1,040 cultures of coli-aerogenes bacteria isolated at 30° from farm dairy equipment and raw milk was classified according to the recommendations of the Coliform Sub-Committee of the Society for Applied Bacteriology (Report, 1949). The distribution of species and types isolated from milk did not differ materially from that for dairy equipment, Klebsiella cloacae, K. aerogenes and Citrobacter freundii being the dominant species, while the incidence of Escherichia coli was relatively low. There was no marked seasonal incidence of any type, though E. coli I formed a slightly higher proportion of the coli-aerogenes microflora in winter, whereas K. aerogenes I was slightly higher in summer. Many of the cultures of the dominant types, K. cloacae, K. aerogenes I and Cit. freundii I, did not form acid and gas from lactose in two days at 37°. Consequently 37° negative, anaerogenic and paracolon strains constituted a relatively high proporton (49%) of the coli-aerogenes microflora.     

Metamorphosis from the Phoront to the Trophont in Hyalophysa*

SYNOPSIS. The nature and sequence of changes involved in the metamorphosis of the phoront of Hyalophysa have been examined in the light microscope using both living and silver-impregnated ciliates. The phoront's infraciliature, which resembles that of the migratory tomite, differentiates to the trophont (feeding stage) infraciliature without an intervening dedifferentiation. The primary visible event of metamorphosis is the growth of the metastomial area that distorts the meridional somatic kineties so that they curve or spiral around it. The distinct borders and intense argentophilia of the metastomial area suggest that it is a discrete organelle which is probably involved in the management and concentration of a large volume of dilute food. The anterior ventral field of kinetosomes, whose presence distinguishes Hyalophysa from Gymnodinioides, forms from a disorganized anterior segment of falciform field 9. The rapid and pronounced elongation of the somatic kineties supports our view that the kinetodesmos elongates by the sliding of its component subfibrils upon one another, and that the accessory kinetosomes seen in the electron microscope become functional at metamorphosis. The movement of the kineties and contractile vacuole pore during metamorphosis suggests that differentiation in this instance is not directed by pellicular “fields” but by morphogenetic movements of the underlying cytoplasm.     

The Axenic Culture of Strains of the Various Syngens of Paramecium aurelia*

SYNOPSIS Strains of the various syngens of Paramecium aurelia respond differently to the culture media developed for Strain 299 of syngen 8. Not only is there a variety of response between the syngens, but strains belonging to the same syngen respond differently to the 3 growth media.     

The opercular brood chambers of Spirorbidae

Brood chambers of Januinae are cuticular and have to be shed to liberate the larvae, whereas those of Pileolaria are bounded by two epithelia and are used repeatedly. Links for interpreting these differences are to be found amongst some of the smaller genera of Pileolariinae. In Amplicaria and Vinearia the embryos are held between a pair of opercular plates, which form distal and proximal cups with the concavities facing each other. They are successive units in a series of sheddings and renewals, found generally in Spirorbidae even on non-brooding opercula. A Janua brood chamber corresponds with the distal component of such a pair, the proximal component being represented by the basal plate. In most Pileolariinae the brood chamber is formed entirely by the proximal component. Amongst Nidificaria species, some hold the embryos in a simple cup with no distal protection, but others have the aboral side of the cup extended and growing over distally, like the dorsal lip of a blastopore. The aperture that remains may be almost closed but can open again to liberate the larvae. Brood chambers of Pileolaria are exactly like that, except that they lack any calcification proximally. Those of Jugaria and Bushiella are similar, but with additional protection through retention of distal plates. Protoleodora species are subarctic and very close to Jugaria and Bushiella in distribution and morphology, but they have less calcification, readily lose their distal plates, and develop soft-walled brood pouch extensions which can accommodate very large broods. There seem to be tenuous links between the Pileolariinae and the Romanchellinae, southern hemisphere spirorbids which incubate in their tubes. Fertilization and spawning need further study.     

The nature of the microbial stimulus affecting sporophore formation in Agaricus bisporus (Lange) Sing

An apparatus is described in which pure cultures of Agaricus bisporus were maintained on composted media in filtered atmospheres free from (a) noxious concentrations of carbon dioxide, and (b) contaminating microorganisms. When grown on compost alone, cultures of A. bisporus did not produce sporophores. Their formation was however stimulated by a covering layer of an unsterilized mixture of peat and chalk (=‘casing’ soil). Autoclaving or fumigating ‘casing’ with propylene oxide decreased populations of contaminating bacteria and prevented sporophore formation. Populations of micro-organisms isolated from unsterile ‘casing’ contained bacteria which when added to pure cultures of A. bisporus stimulated fruit-body formation. Numbers of these stimulators increased when cultured on a carbon-free liquid medium exposed to atmospheres with ethanol, ethyl acetate and acetone or containing the volatile metabolites of A. bisporus. The ability to utilize these volatile chemicals was exploited in a selective technique for isolating sporophore stimulators where aqueous suspensions of mixed bacterial populations were exposed to atmospheres of these materials for 5 days, before aliquots were added to agar media subsequently gelled. The stimulatory bacteria were identified as, or closely related to, Pseudomonas putida.     

New Fibrous Long Spacing Form of Collagen

PRECIPITATION of collagen from solution in the presence of chondroitin sulphates (or certain other glycosaminoglycans), followed by dialysis against water, leads to the formation of the fibrous long spacing (FLS) polymorphic form of collagen. Electron microscopy shows this to consist of banded fibrils with a periodicity in the range 1200–2400 Å and a symmetric intraperiod structure, in contrast to the 600–700 Å periodicity and polarized fine structure characteristic of native collagen fibrils. FLS was originally reported by Highberger et al.^1–3 and has been observed in three principal modifications, FLS I, FLS II and FLS III, differing in periodicity and arrangement of dense bands^4–6. This letter reports a new form of FLS, denoted FLS IV.     

Redescription of Ellobiophrya brevipes (Laird, 1959) N. Comb. (Ciliophora, Peritrichia) and the Fine Structure of its Pellicle and Cinctum

ABSTRACT. A species of peritrich that attaches to gills of the skate, Raja erinacea , was identified by its original describer as a member of Caliperia , a genus characterized by having a noncontractile skeletal rod within the arms of its cinctum and by not having the cinctal arms bonded to one another at their tips. Our observations of the living ciliates confirmed by protargol impregnation and electron microscopy revealed that their cinctal arms are linked by a bouton and that the cytoskeletal structure within them has the fine structure of a myoneme. These characteristics place this peritrich unequivocally in the genus Ellobiophrya and it is thus renamed Ellobiophrya brevipes (Laird, 1959) n. comb. Clumps of epithelial cells clasped by the cincta of E. brevipes show damage at their bases but not on their luminal surfaces. The known species of Ellobiophrya are compared for significant structural differences that separate species of this genus.