Carbohydrate Granules Research Articles

Characterization of a green Stentor with symbiotic algae growing in an extremely oligotrophic environment and storing large amounts of starch granules in its cytoplasm

The genus Stentor is a relatively well-known ciliate owing to its lucid trumpet shape. Stentor pyriformis represents a green, short, and fat Stentor, but it is a little-known species. We investigated 124 ponds and wetlands in Japan and confirmed the presence of S. pyriformis at 23 locations. All these ponds were noticeably oligotrophic. With the improvement of oligotrophic culture conditions, we succeeded in long-term cultivation of three strains of S. pyriformis. The cytoplasm of S. piriformis contains a large number of 1–3 μm refractive granules that turn brown by Lugol’s staining. The granules also show a typical Maltese-cross pattern by polarization microscopy, strongly suggesting that the granules are made of amylopectin-rich starch. By analyzing the algal rDNA, it was found that all S. pyriformis symbionts investigated in this study were Chlorella variabilis. This species is known as the symbiont of Paramecium bursaria and is physiologically specialized for endosymbiosis. Genetic discrepancies between C. variabilis of S. pyriformis and P. bursaria may indicate that algal sharing was an old incident. Having symbiotic algae and storing carbohydrate granules in the cytoplasm is considered a powerful strategy for this ciliate to withstand oligotrophic and cold winter environments in highland bogs.

Sexual segment of the kidney of the lizard, Eutropis carinata: A light microscopic and ultrastructural seasonal study.

We studied seasonal variation of the secretory granules in the epithelial cells of the sexual segment of the kidney (SSK) during the annual sexual cycle in the lizard, Eutropis carinata using light and electron microscopy in correlation with measurements of androgen levels. During the breeding phase, the epithelium of the SSK consists of simple columnar cells with basal nuclei. The cytoplasm contains numerous eosinophilic secretory protein and carbohydrate granules, but lacks glycosaminoglycans. These secretory granules develop during the regenerative phase when the circulating testosterone level increase. During the breeding phase, when the circulating testosterone levels are high, three types of secretory granules can be differentiated in the cytoplasm based on size and opacity; electron translucent type I, electron dense type II, and biphasic type III granules. Type II granules are found at various stages of maturity and degeneration/utilization. All types of secretory granules are released through an apocrine process. Microvilli and tight junctions are prominent at the apical portion of the cell. The cytoplasm contains, Golgi complexes, an abundant network of rough endoplasmic reticulum, numerous tubular mitochondria, condensing, mucus filled and empty vacuoles. Intercellular canaliculi are narrow and indistinct during the regenerative and breeding phases, respectively. During the regressed phase, when the circulating testosterone levels are lowest, the cells are found regressed with wide intercellular canaliculi and devoid of secretory granules. Then the cytoplasm contains a few round mitochondria, Golgi and scanty endoplasmic reticulum.

Histological and histochemical study of female germ cell development in the dusky grouper Epinephelus marginatus (Lowe, 1834).

The developmental stages of female germ cells were analysed in a wild population of the protogynous teleost Epinephelus marginatus (Lowe, 1834). 321 wild dusky grouper females were collected in the South Mediterranean Sea during the spawning season and their ovaries analysed using histological and histochemical techniques. Oocyte morphology, nucleus-cytoplasm ratio (N/C) range, location and movements of cytoplasmic inclusions during primary growth, vitellogenesis and final oocyte maturation were described. The distribution of proteins, lipids and carbohydrates through oocyte development was also investigated in 50 females. Lipid vesicles appeared firstly in the mid ooplasm of oocytes larger than 130 microm, at the beginning of the secondary growth phase. Immediately afterwards, small carbohydrate granules (PAS and Alcian blue positive) appeared before the occurrence of the first yolk granules. Tyrosine-enriched proteins were especially evidenced in the zona radiata interna of late vitellogenic oocytes. Specific lectin binding patterns reflected characteristic differences in the content and distribution of specific sugar moieties expressed in the oocytes during vitellogenesis and final maturation. At the end of vitellogenesis and during final maturation, follicular cells, zona radiata, and cortical alveoli were characterised by a strong increase of specific binding for WGA.

Papillary Tumor of the Pineal Region of a Dog

A 3-year-old, intact, male Beagle dog developed clinical signs of pleurothotonus and altered head position to the right, neck pain, nystagmus, hyperreflexia of the left forelimb, and hyperextension of both forelimbs. Magnetic resonance imaging enabled a tentative diagnosis of thalamic neoplasia with incidental hydromyelia at the level of the second cervical vertebra. The animal was euthanatized due to the poor prognosis, and a necropsy was performed. A large, well-demarcated, nonencapsulated, and focally infiltrative mass was present in the approximate location of, and effacing, the pineal gland. The mass was composed of densely packed polyhedral neoplastic cells that exhibited epithelial characteristics, such as intercellular junctions, and contained carbohydrate granules and occasionally melanin granules. Immunohistology confirmed that neoplastic cells expressed neuron-specific enolase and, in a small proportion, cytokeratin. These combined findings led to the diagnosis of a papillary tumor of the pineal region, a tumor not previously described in dogs.

Temporal Changes in State Transitions and Photosystem Organization in the Unicellular, Diazotrophic Cyanobacterium Cyanothece sp. ATCC 51142.

The unicellular Cyanobacterium Cyanothece sp. ATCC 51142, grown under alternating 12-h light/12-h dark conditions, temporally separated N2 fixation from photosynthesis. The regulation of photosynthesis was studied using fluorescence spectra and kinetics to determine changes in state transitions and photosystem organization. The redox poise of the plastoquinone (PQ) pool appeared to be central to this regulation. Respiration supported N2 fixation by oxidizing carbohydrate granules, but reduced the PQ pool. This induced state 2 photosystem II monomers and lowered the capacity for O2 evolution. State 2 favored photosystem I trimers and cyclic electron transport, which could stimulate N2 fixation; the stimulation suggested an ATP limitation to N2 and CO2 fixation. The exhaustion of carbohydrate granules at around 6 h in the dark resulted in reduced respiratory electron flow, which led to a more oxidized PQ pool and produced a sharp transition from state 2 to state 1. This transient state 1 returned to state 2 in the remaining hours of darkness. In the light phase, photosystem II dimerization correlated with increased phycobilisome coupling to photosystem II (state 1) and increased rates of O2 evolution. However, dark adaptation did not guarantee state 2 and left photosystem I centers in a mostly monomeric state at certain times.

Composition of the carbohydrate granules of the cyanobacterium, Cyanothece sp. strain ATCC 51142

Cyanothece sp. strain ATCC 51142 is an aerobic, unicellular, diazotrophic cyanobacterium that temporally separates O2-sensitive N2 fixation from oxygenic photosynthesis. The energy and reducing power needed for N2 fixation appears to be generated by an active respiratory apparatus that utilizes the contents of large interthylakoidal carbohydrate granules. We report here on the carbohydrate and protein composition of the granules of Cyanothece sp. strain ATCC 51142. The carbohydrate component is a glucose homopolymer with branches every nine residues and is chemically identical to glycogen. Granule-associated protein fractions showed temporal changes in the number of proteins and their abundance during the metabolic oscillations observed under diazotrophic conditions. There also were temporal changes in the protein pattern of the granule-depleted supernatant fractions from diazotrophic cultures. None of the granule-associated proteins crossreacted with antisera directed against several glycogen-metabolizing enzymes or nitrogenase, although these proteins were tentatively identified in supernatant fractions. It is suggested that the granule-associated proteins are structural proteins required to maintain a complex granule architecture.

A Comparative Study of the Storage Carbohydrate Granules from Euglena (Euglenida) and Pavlova (Prymnesiida)1,2

ABSTRACT The storage carbohydrate granules from Euglena and Pavlova were compared by light and electron microscopy. Freezeetch studies demonstrated that while both types of granules are crystalline, they have different structures. The elemental microfibril of the euglenoid granule measures 4 nm, and the elemental striation of the granule from Pavlova is 22 nm. The granules each have a unique X‐ray diffraction pattern. The storage carbohydrate granules from Pavlova are not the same as paramyton, and the term “paramylon” should be reserved for the euglenoid storage carbohydrate.

BLOAT IN FEEDLOT CATTLE: EFFECTS ON RUMEN FUNCTION OF ADDING 4% SODIUM CHLORIDE TO A CONCENTRATE DIET

Four fistulated cows were given alfalfa hay or all-concentrate diets containing either 0.5% or 4.0% NaCl (salt). The low-salt diet leads to the development of rumen conditions associated with bloat. When given the low-salt concentrate diet, cows had rumen fluid with lower pH and protozoal counts, and higher viscosity, soluble carbohydrate concentration, and dry matter content than when they were given alfalfa hay or the high-salt concentrate diet. Massive lysis of bacterial cells was observed in rumen digesta from cows on the low-salt diet and intact cells were full of reserve carbohydrate granules and were surrounded by thickened fibrillar capsules. These changes were largely absent in cows on the other two diets. Water intake and the total water content of the rumen were lower with the low-salt diet than with the other diets. The flow of water through the rumen was highest with alfalfa hay, lowest with the low-salt diet, and intermediate with the high-salt diet. It was concluded that adding 4.0% NaCl to an all-concentrate diet of a type implicated in feedlot bloat increased the flow of material from the rumen and, in so doing, appeared to alter fermentation in such a way as to oppose development of conditions that lead to bloat.

The substructure of cytoplasts obtained from Acetabularia mediterranea

Cytoplasts have been obtained from Acetabularia , and their substructure was examined after 3 and 11 days. After both periods of time, the chloroplasts display bundles of thylakoids; the latter are not inflated. The pseudograna vary in number according to the time of the daily cycle in the 11-day-old cytoplasts. The number of carbohydrate granules is variable, but the granules themselves are small; they have diffused limits after 3, but not after 11 days since the cytoplasts were obtained. The stroma is dense. The chloroplasts do not seem to be engaged in a process of division. Mitochondria contain a system of cristae abnormally developed. The Golgi apparatus is still present but has only few inflated vesicles; small granules are usually visible in the vicinity of the dictyosomes. The substructure of these organelles is compared with that in anucleate algae, and the possible significance of the observations is discussed.

Origin and Cytochemical Analysis of Yolk in Oogenesis of <i>Locusta migratoria</i>

1. In the present work, the origin and cytochemistry of both the types of yolk (fatty and compound) in the oogenesis of Locusta migratoria are discussed.2. The fatty yolk globules (L3 bodies), consisting of triglycerides only, are derived from the Golgi bodies (L1 bodies), consisting of phospholipids only, through an intermediate stage, the duplex Golgi bodies (L2 bodies) which contain phospholipids in their cortices and triglycerides in their medullae. In this process the thick cortex of duplex Golgi bodies becomes greatly attenuated.3. The compound yolk globules have their origin from the fine circumnuclear carbohydrate granules of the early oocyte which arrange themselves at the cortical ooplasm in the late stages of oogenesis, where they grow and form the compound yolk globules.4. The protein moiety of the compound yolk is formed under the influence of nucleolar RNA which plays an important role in protein synthesis.5. Cytochemically, the compound yolk consists of carbohydrates (1:2 glycol groups) and acidic proteins; it is devoid of mucopolysaccharides and glycogens.6. The mitochondria, throughout oogenesis, remain in the form of small granules and do not take part in yolk synthesis.