Representative electron micrographs, from the study of eight strains of L forms and one strain of Mycoplasma, are presented. A- and B-type L forms were derived from two strains of Proteus, two other L forms were derived from a diphtheroid and from a staphylococcus strain, and two strains (designated as LX) were isolated from L forms derived from a group A beta-hemolytic streptococcus and from a staphylococcus. The Mycoplasma strain was isolated from goats. Sections were made of young colonies grown within agar and from parts of surface colonies embedded in the agar. B-type L colonies of Proteus were produced by inoculation of bacteria into media containing penicillin. The large bodies developing from the bacteria and the organisms in B-type L colonies of Proteus, like the parent bacteria, had a cell wall consisting of a plasma membrane and an outer cell wall. The loss of rigidity in the cell wall indicated an alteration in its structure. The A-type L cultures of Proteus consisted of irregular branching masses extending in several directions, of small dense organisms corresponding to the elementary corpuscles present in cultures of Mycoplasma, and of intermediary forms. In contrast to the B-type, all organisms in the A-type colonies were surrounded by a single unit membrane corresponding to the plasma membrane of bacteria. The structures inside the cell membrane, both in the A- and B-type, seemed to correspond to the structure of the parent bacteria, which contained ribosomes and threads of DNA. The elementary corpuscles formed chains and filaments, and, apparently, these corpuscles took part in the multiplication by gradual enlargement. The organisms seen in the cultures of all L forms and Mycoplasma studied, except in the B-type L forms of Proteus, corresponded in size, shape, and structure, as well as in the development of elementary corpuscles, to the organisms in the A-type L form of Proteus. In contrast to the spherical organisms usually seen in broth cultures, the organisms in young cultures of Mycoplasma, which were grown within the agar, were similar in morphology, as well as in the discernible structure of the organisms, to L forms. Significant morphological and structural differences were not apparent between the L forms and Mycoplasma (in cultures grown within agar media) under the conditions of this investigation. 相似文献
This is the fourth paper in a series on the distribution of blood groups among Indians of South America. It reports the findings on the Indians of Chile and the Polynesians of Chile's Easter Island. Blood specimens were procured from the following putatively pure Indians and unmixed Polynesians: 44 Alacaluf of Puerto Eden, Isla Wellington, 141 Mapuche (Araucanian) of Lonquimay, Malleco Province, 80 Atacameños of Antofagasta Province, and 45 Polynesians of Easter Island. These 310 samples were tested for blood factors in the A-B-O, M-N-S-s, P, Rh-Hr, Lutheran, K-k, Lewis, Duffy, Kidd and Diego systems, and for the Wright (Wra) agglutinogen. Serum samples were tested for haptoglobins and transferrins. Hemolysates prepared from the blood clots were tested for hemoglobin types. The results are presented as phenotype incidences and calculated gene frequencies in appropriate tables. Locations of the populations from which blood samples were procured are shown on two maps. The high frequencies for the O gene usually reported for South American Indians obtain in putatively pure Chilean Indians but A1 is high in Easter Island Polynesians. In both Indians and Polynesians M, s, R1 (CDe), R2 (cDE), Lub, k, LeH, and Fya gene frequencies are high and B, N, S, Mia, Vw, Rº (cDe), r (cde), Lua, K, Le1, Fyb, and Wra (Ca) are low or absent. The Diego (Di) gene is present in the Mapuche and Atacameños but absent in the Alacaluf and Polynesians. Hp1 gene frequencies were determined only in the Alacaluf and Atacameños, in which they are 0.48 and 0.67 respectively. Transferrins were determined for the Alacaluf and Atacameños Indians and all were classified as Tf C. All Chilean Indian and Polynesian specimens were tested electrophoretically for hemoglobin types and all contained only hemoglobin (A) as a major component. 相似文献
The cutaneous manifestations of the male external genitalia are difficult to diagnose. They may be associated with systemic disease (Reiter''s disease, psoriatic arthritis, angiokeratoma corporis diffusum). In dealing with a lesion of this area that does not heal, adequate biopsy is advisable to rule out malignant disease (Bowen''s disease, melanoma, Kaposi''s sarcoma, Paget''s disease, erythroplasia). 相似文献
Prior to the first oviposition, a receptivity centre, perhaps neurosecretory cells in the brain, controls the female's acceptance of courting males. In L. maderae this centre is affected by starvation. A brief exposure to food can induce mating but is inadequate for oöcyte development. Before the first ovulation starvation has no effect on receptivity in N. cinerea.
In N. cinerea mechanical stimulation caused by the firm insertion of the spermatophore in the bursa copulatrix releases stimuli via the nerve cord to the brain which render the female unreceptive and, at the same time, increases the activity of the corpora allata resulting in rapid development of the oöcytes.
The mechanical presence of the oötheca in the uterus also has two principal effects. Like spermatophore insertion, it inhibits mating. But its effect on the corpora allata is inhibitory, rather than stimulatory, and, consequently, the oöcytes remain underveloped for almost the entire gestation period. The effectiveness of inhibitory stimulation from the stretched uterus depends upon the period in the reproductive cycle in which it occurs-i.e. on the physiological state of the female. In N. cinerea uterine stretching inhibits mating and oöcyte development after oviposition or during gestation but is not effective when exerted during the first pre-oviposition period. In P. surinamensis, uterine stretching does not inhibit the corpora allata prior to the first ovulation but does prevent oöcyte development during gestation.
In fed L. maderae and N. cinerea there appears to be a synergistic action of nutrition and mating in controlling the rate of oöcyte development. Mating (mechanical) and feeding (chemical) stimuli are both usually required for activating the corpora allata to their fullest extent so that the oöcytes mature at their maximum rate. There is some indication that mating stimuli in N. cinerea and L. maderae are effective in further stimulating the corpora allata only if the corpora allata have reached a certain level of activity, if activating stimuli have begun to occur in the brain, or if the mating stimulus occurs in combination with nutritional factors. Thus, the corpora allata in starved virgin females of N. cinerea become sufficiently active so that some yolk is deposited in the oöcytes but these oöcytes do not mature; mating is effective in further stimulating the endocrine glands in these starved females and oviposition occurs in about the normal period. In starved virgins of L. maderae the corpora allata are virtually inactive and yolk is not deposited in the oöcytes; mating has no effect on oöcyte development in starved females. D. punctata differs from both the above species in that the corpora allata in the virgin female usually remain inactive whether she feeds or starves. Mating stimuli alone can activate the corpora allata, in fed or starved females, and consequently the oöcytes mature. 相似文献
Determination of the frequency response of pneumotachographs is needed whenever they are used to measure high-frequency flows, such as in the forced oscillation method. When screen and capillary pneumotachographs are calibrated using an adiabatic compression in a closed box as a reference impedance, they can be adequately described by a series of inertial-resistive elements. However, this type of reference impedance strongly differs from the actual respiratory impedance (ZL). We studied the frequency response of pneumotachographs up to 250 Hz in reference to the impedance of a compressible gas oscillating in a long tube, taken as a more generalizable model of actual ZL. We found that, with this device, the series resistance-inertance models fail to describe the frequency response of the pneumotachograph. However, when compressible effects in the pneumotachograph are taken into account by adding to the resistive models a compliance (Cpn) corresponding to the compression in half of the inner volume of the pneumotachograph, the agreement with experiments becomes satisfactory. Gas compression-related phenomena were demonstrated to be negligible only when the parameter omega Cpn magnitude of ZL is much smaller than 1 (omega pulsation). Results obtained in normal humans have shown that such a correction is required above 100 Hz. Similar correction at lower frequency might also be necessary in cases of large respiratory impedance (e.g., babies, subjects with pathological lungs, and intubated subjects). 相似文献