Ultrastructure of the Pro-adenohypophysis of the River Lamprey,Lampetra fluviatilis,During Gonad Maturation

Abstract The pro-adenohypophysis (pro-AH) of migrating adult river lamprey, Lampetra fluviatilis, has been examined from October, when the gonads are developing slowly, until May, when the sexual maturation is completed. Two granulated cell types are dominating. One is chromophobic (C2, 95 nm), the other is basophilic (B1-B3) and probably gonadotropic. The mean diameter of the basophil secretory granules increases from 150 nm in October to 220 nm in April and May. The staining affinity of a rare, granulated cell type (D, 115 nm) has not been established. No acidophil cells are found in the pro-AH. The ultrastructural characteristics of the lead hematoxylin positive cells found sometimes in paraffin sections are unknown. Non-glandular stellate cells are common. They contain microfilaments, are probably contractile, and transform to phagocytes during the last months before spawning. This phagocytosis involves only the basophil cells. It is suggested that the stellate cells in this way destroy excess hormone. All cell types in the pituitary accumulate large irregular lipid droplets during the last month before spawning. These lipid droplets seem to be expelled from residual bodies as an end product of autolysis and phagocytosis.     

The fine structure of the parabronchi and the gas exchange area of the Adelie penguin lung

The parabronchi of the Adelie penguin are endowed with wide atria forming pockets between a loose meshwork of bundles of smooth muscle cells lining the parabronchial lumen. The atrial epithelium is of variable thickness and bears numerous microvilli, which are overlain by/or embedded in sheets or whorls of lamellar material ("trilaminar substance", diameter of one lamella 8 ..10 nm) forming layers of very variable thickness. The cells contain either stacks or whorls of this material or roundish lamellated bodies, and are interconnected by desmosomal contacts as well as what presumably represent tight junctions. Underneath the epithelium and within the bundles of muscle cells regularly nerve fibres have been found. The diameter of the morphological air/blood barrier is about 165...210 nm in thin areas, excluding a 12...20 nm thick layer covering the luminal plasma membrane of the air capillary epithelium. The blood capillary endothelium ordinarily is markedly thicker (40...250 nm) than the air capillary epithelium (17...25 nm). The basal lamina between endo- and epithelium is a uniform structure measuring about 95...105 nm. The endothelial cells are interconnected by desmosomal and probably tight junctions.     

Effect of mutations in the uvrA and recA genes on the photoreactivity of Escherichia coli cells irradiated by UV light (250 and 313 nm)

The relative contribution of photo- and non-photoreactivable damages to the lethal effect of far-(250 nm) and mid-(313 nm) wave UV in isogenic bacterial cells Escherichia coli WP2 (wild type, uvrA and recA mutants) was estimated. It has been demonstrated that the value of non-photoreactivable damages increases with lambda of UV (250----313 nm) and depends on the genotype (uvrA and recA).     

Properties of Anabaena variabilis cells grown in the presence of diphenylamine

Anabaena variabilis cells have been cultivated in the presence of diphenylamine (12 mg/l) which inhibits the biosynthesis of β-carotene, echinenone and zeasanthin. The content of chlorophyll a is also reduced by diphenylamine. The biosynthesis of myxoxanthophyll is, however, stimulated by this reagent.

The membrane fragments prepared from Anabaena cells grown in the presence of diphenylamine have the activities of both Photosystem 1 (NADP⁺ reduction with DCIP-ascorbate as electron donor) and Photosystem 2 (DCIP reduction with 1,5-diphenylcarbazide as electron donor).

The fluroescence spectra of these cells at 77°K show peaks at 696 and 731 nm and a shoulder around 687 nm. The fluorescence intensity at 687 and 696 nm is higher in these cells than in normal-Anabaena cells.     

The neurosecretory cells of the brain and suboesophageal ganglion of Chironomus riparius

The neurosecretory cells of the supra- and suboesophageal ganglia of young, unmated, adult male midges, Chironomus riparius, have been examined by both light and electron microscopy. The 5 cell types recognized have been placed in three major categories on the basis of their ultrastructural characteristics:—α₁ cells, of which there are 8 in each medial neurosecretory cell (MNC) group and 3 in each group of ventral neurosecretory cells (VNC), contain electron-dense granules, 150 to 200 nm in diameter; α₂ cells containing irregular, electron-dense granules, 70 to 120 nm in diameter comprise the remaining 3 cells in each VNC group and the 2 or 3 cells in each outer neurosecretory cell (ONC) group; α₃ cells, of which there are 1 or 2 on each side of the midline in the ventral cortex of the sub-oesophageal ganglion (SNC₂), contain electron-lucent, spherical granules, 70 to 120 nm in diameter. The β cells contain spherical or ellipsoidal, electron-lucent granules, 80 to 100 nm in diameter, and make up the lateral neurosecretory cell (LNC) groups, each of three or four cells. The γ cells contain both spherical and flattened, electron-dense granules, 130 to 160 nm in diameter and 150 to 250 by 70 to 150 nm in size respectively, only 1 cell of this category being found in each half of the suboesophageal ganglion in the dorsal cortex (SNC₁). Axons from the MNC and VNC form the nervi corporis cardiaci I (NCCI) and those of the LNC and ONC, the nervi corporis cardiaci II (NCCII). Those of the SNC₁ appear to enter the wall of the stomodaeum but axons of the SNC₂ could not be traced.     

Luminescence parameters of nuclear blood cells during the immune response process

The synthetic activity of nuclear blood cells in the process of immunization of rabbit with ovalbumin was studied by luminescence microspectroscopy . We followed the parameter alpha, the ratio between the intensities of the red (640 nm) and green (530 nm) components of the luminescence spectrum of acridine orange fluorochrome cells. The antiserum titre was determined too. The data obtained make it possible to correlate the increase in alpha of the immunocompetent cells with the content of antibodies synthesized by these cells in response to the protein antigen. It has been shown that within definite limits the parameter alpha does determine the synthetic activity of the immunocompetent cells.     

Endocrine cells of mucosal epithelium in the distal part of the intestine of Lacerta vivipara

The epithelium of the distal part of intestine of the lizard Lacerta vivipara has been studied by light and electron microscopy. The total number of endocrinocytes (argyrophilic cells) was found to increase from small bowel (57 +/- cell/mm2) to colon (9 +/- 69), and cloaca (99 +/- 8). Although the number of argentaffin cells increases from the small bowel to colon, cell decrease occurs from colon (42 +/- 6 cell/mm2) to cloaca (65 +/- 10 cell/mm2). On electronograms of the colon mucosal epithelium four types of endocrinocytes were identified. Type I--with secretory granules polymorphic for the size and form, with a high electron density core, and average size 206 +/- 31 nm. Type II--with secretory granules 265 +/- 20 nm in size, having spherical form and highly electronic dense contents. Type III--contains largest (350 +/- 12 nm), spherical, oval or irregularly-shaped secretory granules, with contents of various electronic density. Type IV--endocrine cells having small (176 +/- 5 nm) spherical or oval secretory granules with a highly electronic dense core. Besides, "mixed" cells were identified, whose cytoplasm contained simultaneously mucous and endocrinous granules.     

A critical study of the measurement and calibration of circular dichroism

A critical study has been made of circular dichroism (CD) measurements at the wavelengths around 500, 290, and 220 nm. Instruments calibrated at 290 nm with (+)-camphor-10-sulfonic acid gave results for molecular ellipticities [θ] showing deviations up to >30%, at both 220 and 490 nm. Older instruments tended to given higher values of [θ] at 490 nm and lower values at 220 nm, probably due to the age of the Pockel cells.     

A photosynergistic lethal effect in the irradiation of yeasts with long-wave ultraviolet and visible light

A lethal synergistic effect which is expressed as the nonadditive summing of the damaging effect of each irradiation separately has been found during the investigation of combined action of longwave ultraviolet (UV) rays (337 nm or 365 nm) and visible light (400-600 nm) on the yeast cells. Based on the data on different mechanisms of lethal effect of longwave UV and visible light, it has been suggested that the basis of the photosynergistic effect is the mutual intensification of the photo-destructive processes occurring in different intracellular structures and processes induced by different endogenous sensitizers.     

The Spectral Sensitivities of Single Cells in the Median Ocellus of Limulus

The spectral sensitivities of single Limulus median ocellus photoreceptors have been determined from records of receptor potentials obtained using intracellular microelectrodes. One class of receptors, called UV cells (ultraviolet cells), depolarizes to near-UV light and is maximally sensitive at 360 nm; a Dartnall template fits the spectral sensitivity curve. A second class of receptors, called visible cells, depolarizes to visible light; the spectral sensitivity curve is fit by a Dartnall template with λ_max at 530 nm. Dark-adapted UV cells are about 2 log units more sensitive than dark-adapted visible cells. UV cells respond with a small hyperpolarization to visible light and the spectral sensitivity curve for this hyperpolarization peaks at 525–550 nm. Visible cells respond with a small hyperpolarization to UV light, and the spectral sensitivity curve for this response peaks at 350–375 nm. Rarely, a double-peaked (360 and 530 nm) spectral sensitivity curve is obtained; two photopigments are involved, as revealed by chromatic adaptation experiments. Thus there may be a small third class of receptor cells containing two photopigments.     

Antenna organization and evidence for the function of a new antenna pigment species in the green photosynthetic bacterium Chloroflexus aurantiacus

Whole cells and isolated chlorosomes (antenna complex) of the green photosynthetic bacterium Chloroflexus aurantiacus have been studied by absorption spectroscopy (77 K and room temperature), fluorescence spectroscopy, circular dichroism, linear dichroism and electron spin resonance spectroscopy. The chlorosome absorption spectrum has maxima at 450 (contributed by carotenoids and bacteriochlorophyll (BChl) a Soret), 742 (BChl c) and 792 nm (BChl a) with intensity ratios of 20:25. The fluorescence emission spectrum has peaks at 748 and 802 nm when excitation is into either the 742 or 450 nm absorption bands, respectively. Whole cells have fluorescence peaks identical to those in chlorosomes with the addition of a major peak observed at 867 nm. The CD spectrum of isolated chlorosomes has an asymmetric-derivative-shaped CD centered at 739 nm suggestive of exciton interaction at least on the level of dimers. Linear dichroism of oriented chlorosomes shows preferential absorption at 742 nm of light polarized parallel to the long axis of the chlorosome. This implies that the transition dipoles are also oriented more or less parallel to the long axis of the chlorosome. Treatment with ferricyanide results in the appearance of a 2.3 G wide ESR spectrum at g 2.002. Whole cells grown under different light conditions exhibit different fluorescence behavior when absorption is normalized at 742 nm. Cells grown under low light conditions have higher fluorescence intensity at 748 nm and lower intensity at 802 nm than cells grown under high light conditions. These results indicate that the BChl c in chlorosomes is highly organized, and transfers energy from BChl c (742 nm) to a connector of baseplate BChl B792 (BChl a) presumably located in the chlorosome baseplate adjacent to the cytoplasmic membrane.     

Role of DNA damage in the inactivation of Saccharomyces cerevisiae yeasts by 313-nm ultraviolet light

The relative contribution of respiration photoinhibition and DNA damage in the lethal effect induced by 313 nm ultraviolet light (UV) has been investigated in some strains of the yeast Saccharomyces cerevisiae. It has been shown that cells inactivation is essentially due to photo-induced damage to DNA. By photoreactivation experiments it has been found that dimers of the pyrimidine bases are the main lethal photoproducts induced in the DNA by 313 nm ultraviolet light.     

A new fluorometric method for the determination of pyridoxal 5′-phosphate

A new fluorometric method using semicarbazide for the determination of pyridoxal and pyridoxal 5′-phosphate (PLP) in whole blood, red cells and plasma has been developed. Semicarbazide breaks the Schiff base of PLP and proteins by “trans-Schiffization” reaction and forms semicarbazone of PLP. The semicarbazone of PLP emits strongly at 460 nm when excited at 380 nm. Several metabolic intermediates were tested for the possible interference. Only pyridoxal was found to interfere. The interference can be corrected since pyridoxal emits at 380 nm when excited at 320 nm. Using this method we found that rabbit red cells in vivo are freely permeable to PLP.     

Further evidence from sectioned material in support of the existence of a linear terminal complex in cellulose synthesis

Summary Transmembrane linear terminal complexes considered to be involved in the synthesis of cellulose microfibrils have been described in the plasma membrane ofBoergesenia forbesii. Evidence for the existence of these structures has been obtained almost exlusively using the freeze etching technique. In the present study an attempt has been made to complete these studies using conventional fixation, staining, and sectioning procedures. In developing cells ofBoergesenia forbesii, strongly stained structures traversing the plasma membrane and averaging 598.9 nm ± 171.3 nm in length, 28.7 nm ± 4.2 nm in width, and 35.2 nm ± 6.6 nm in depth have been demonstrated. These structures are considered to be linear terminal complexes. At their distal (cell wall) surface, they appear to be closely associated with cellulose microfibrils. At the proximal (cytoplasmic) surface, they are associated with microtubules and polysomes. A model of the possible interrelation of the terminal complexes and microtubules leading to the generation of cell wall microfibrils is proposed.     

Lack of induction of non-targeted mutations in intact bacteriophage by UVB (313 nm), UVA (334 nm, 365 nm) and visible (405 nm) irradiation of host cells

Mutation to virulence has been measured in intact bacteriophage lambda 15 infected into host cells pre-treated with UVC (254 nm), UVB (313 nm), UVA (334 nm, 365 nm) or visible (405 nm) radiations. We have confirmed that UVC radiation leads to a large enhancement (maximum enhancement factor of 140 in wild-type) of the background spontaneous mutation frequency (non-targeted mutagenesis) and have further shown that this is at least partially dependent on excision repair (maximum enhancement factor of 14 in uvrA strain). In contrast, UVB (313 nm) radiation enhances the mutation frequency by less than a factor of 2. Longer wavelength UVA radiation (334 nm, 365 nm) actually reduces the mutation frequency to 25% of the background levels presumably by reducing the levels of viral replication occurring in the host cells. A visible wavelength (405 nm) has no effect on mutation frequency over the fluence range employed.     

Light- and electron-microscopic studies on the secretory cytology of the adenohypophysis of the Japanese quail,Coturnix coturnix japonica

The effects of thyroidectomy, adrenalectomy, and castration on the pars distalis of male Japanese quail, and of injection of LH-RH on sexually inactive females, were investigated by light and electron microscopy. Correlation between light and electron microscopy was attained by use of alternate thin and thick sections. Six types of secretory cells were identified and the ultrastructural characteristics described. Putative endocrine functions have been designated on the basis of responses to experimental interventions and on other criteria. The putative STH cells are characterized by the presence of large dense secretory granules (250-300 nm) that are stained with orange-G by the trichrome method. They occur only in the caudal lobe and appear to be unchanged by castration, thyroidectomy, adrenalectomy and LH-RH injection. The putative prolactin cells are characterized by large (400-600 nm), spherical or polmorphic, dense secretory granules stainable with acid fuchsin and aniline blue; prominent Golgi apparatus and well developed endoplasmic reticulum with densely packed, regularly parallel lamellae. They are found mainly in the cephalic lobe. The prolactin cells develop some vacuolization after adrenalectomy and undergo some degeneration after castration. The ACTH cells, which are restricted to the cephalic lobe, are identified by the dense, spherical granules (250-300 nm) that are stained with acid fuchsin. After adrenalectomy, they lose their secretory granules and are transformed into large, chromophobic adrenalectomy cells. TSH cells are so designated by their response to thyroidectomy including loss of their fine secretory granules and transformation to large, vacuolated thyroidectomy cells. We have found TSH cells and thyroidectomy cells only in the cephalic lobe. Basophilic cells, considered to be gonadotropes, occur in both the cephalic and caudal lobes. The gonadotropes of the cephalic lobe appear to have slightly larger (120-200 nm) granules than the caudal lobe (120-150 nm). However, after castration, the gonadotropes in both lobes become hypertrophied and vacuolated and are transformed into mutually indistinguishable castration cells. Twenty minutes after injection with LH-RH, the gonadotropes of both lobes increase in size and number, degranulate, develop vacuoles in the cytoplasm, and appear very similar to castration cells.     

New photo-induced effects of reactivation and protection of yeast cells under lethal UVB radiation

Brief exposure of yeasts to low-intensity monochromatic light (400–730 nm) has revealed the effects of photoreactivation and photoprotection of the cells inactivated by medium wave UVB radiation (290–320 nm). The red spectral region with a maximum at 680 nm has been found to be the most active in the initiation of photoreactivation and photoprotection. It has been noted that, according to the regularities investigated, these processes differ fundamentally from the known processes of enzymatic photoreactivation and photoprotection, which have a spectral response limited by, respectively, blue (<450 nm) and near (<380 nm) UV light. The data obtained make possible to consider the observed effects of photoreactivation and photo-protection as the manifestation of functioning of some light-dependent defense system capable of increasing the resistance of cells to UVB radiation.     

Nerve ultrastructure of the arteries of the brain stem]

Ultrastructure of the nerve apparatus in the arteries of the brain base has been studied in cats. The structure of peri- and adventitial nerves has been investigated electron microscopically. Three types of efferent axons and four types of synaptic vesicles (small agranular and granular, large granular, large electron opaque vesicles) have been revealed. Vesicle-containing axons in the brain arteries approach the external smooth muscle cells of about 80 nm. Terminal axonal dilatations possessing direct and mediated connections with muscular cells of the middle tunica have been revealed.     

Bacillus thuringiensis fluorescence induced by anaerobiosis and its relation to the cellular functional state

The fluorescence spectra of Bacillus thuringiensis native cells at 340 nm induction have been investigated. The spectral curve has 440-445 and 510-515 nm maximums of fluorescence of pyridine nucleotides (PN) and flavoproteins (FP). The induction of PN and FP fluorescence under anaerobiosis resulted from bacterium breath has been found. The fluorescence induction is connected with the viability of cells. The amplitude of induced fluorescence is in a linear dependence on the number of vegetative cells in medium. The given experimental approaches may be used in a course of development of methods of continuous control over the physiological state change of microorganisms.     

Analysis of substances issuing from Zajdela ascitic hepatoma cells after exposure to UV radiation of different wave-lengths. I. Relationship to dose]

The release of substances from the Zaidela ascitic hepatoma cells after irradiation with physiological doses of short-wave (254 nm) and long-wave (300-380 nm) UV light (far and near UV light) has been studied spectrophotometrically. Within the range of 200-520 nm, the absorption spectra of releasing substances show maxima at 215 and 260 nm and are identical to spectra of non-irradiated cells. The amount of substances increases with dose making up, at the maximal alteration, 180-220%, of the amount releasing from non-irradiated cells. Irradiation with far UV light exceeds by one order that with near UV light. The effect of minimum doses is opposite to the action of high doses: the release of substances from irradiated cells is much less.