Reclinomonas americana N. G., N. Sp., a New Freshwater Heterotrophic Flagellate

ABSTRACT. A new heterotrophic flagellate has been discovered from sites in Maryland, Michigan and Wyoming. The flagellate resides within a lorica constructed of a meshwork of intertwined fibrils with the outer surface invested with nail-shaped spines. The organism "reclines" within the lorica with its ventral aspect directed upward, and has two heterodynamic flagella, neither of which bears mastigonemes. One flagellum is directed upward and the other is arched over the ventral aspect of the body. Ingestion of bacteria takes place at the left posterior half of the cell. The organism is anchored to the lorica on the right posterior side by a series of regularly spaced cytoplasmic bridges and at the left anterior of the cell by a cytoplasmic appendage similar to the "languette cytoplasmique" found in some bicosoecids. The right side of the cell is raised into a flattened lip with the outer margin reinforced by a ribbon of microtubules. The new flagellate has mitochondria with tubular cristae and lacks a Golgi. A new genus is created to accommodate both the new flagellate described herein and Histiona campanula Penard. A new family is proposed to include the new genus and Histiona.     

Effects of Season and Low Temperature on Polypeptides from Thylakoids Isolated from Chloroplasts of Pinus silvestris

Thylakoids isolated from pine chloroplasts were solubilized by sodium dodecyl sulphate and the polypeptides were separated by polyacrylamide gel electrophoresis. The chlorophyll-protein complexes, P700-CPa₁ and LH-CPa/b, had apparent molecular weights of 92,000 and 25,000, respectively. When the chlorophyll of P700-CPa₁ was extracted or photobleached, the apoprotein of P700-CPa₁ appeared as a pronounced peak in the polypeptide scan profile. The molecular weight of the apoprotein was 70,000. During autumn and winter the complex P700-CPa₁ was destroyed. This was primarily caused by bleaching of chlorophyll, as the 70,000 apoprotein increased in the scan profile when the complex P700-CPa₁ decreased. The winter destruction of P700-CPa₁ was less pronounced in old needles than in young. Freezing of frost-hardened seedlings did not change the polypeptide scan profile, unless the temperature was lowered below the frost-killing point followed by thawing and post-treatment in light or darkness above 0°C. Again the main destruction occurred in the P700-CPa₁ complex, but in this case no significant increase of the apoprotein was observed. These alterations in the polypeptide scan profile of frost-killed needles were not caused by the low temperature treatment as such, but they occurred after thawing of the needles.     

Redescription of the clam shrimp Lynceus gracilicornis (Packard) (Branchiopoda, Conchostraca, Lynceidae) from Florida, with notes on its biology

Clam shrimps of the family 1.ynccidac differ markedly from all other families of the Conchostraca. The biology and morphology of the genus Lynceus are poorly known. In North America the genus is represented by four species: L. brachyurus, L. mucronatus, L. brevifrons and L. grarcilicornis. The last species, previously known from two localities in Texas, is reported from an ephemeral pond in north Florida. Amoung the characters distinguishing L. gracilicornis from North American congeners arc dimorphic male claspers and a broad, straight rostral margin. Females are distinct in having a smoothly rounded, distal rostra1 margin. External and internal morphology are described using light and scanning electron microscopy. Scanning electron microscopy reveals the presence of frontal setose sensory fields and a small rostral pit in both sexe5. Numerous setal types are described from the claspers and posterior thoracopods. Internal structures include a large anterior hepatopancreas, C-shaped gut and large paired gonads ventro-lateral to the gut.     

Arrhenius plots and the involvement of thermotropic phase transitions of the thylakoid membrane in chilling impairment of photosynthesis in thermophilic higher plants

Abstract Breaks and discontinuities in Arrhenius plots of physiological and physical properties of thylakoids are not diagnostic of thermotropic lipid phase transitions of the membrane. Bulk lipid transitions, as first inferred by the membrane phase transition hypothesis, do not occur in any higher plant at chilling temperatures. Solidification of some varying, but always minor, fraction of the total membrane lipid does take place. However, the presence of minor domains of solid thylakoid membrane lipid at chilling temperatures is not unique to chilling sensitive plants but is also found in tolerant species. Minor solidification may in some plants, or groups of plants, be controlled by the specific molecular species of phosphatidylglycerol only recently investigated. In plants containing little, or no, phosphatidylglycerol with this positional distribution of fatty acids, other yet unknown constituents of the membrane must fill a similar function, since DSC thermograms indicate minor solidification also in isolated, unperturbed thylakoids from chilling tolerant species. However, chilling induced phase transitions, or other perturbations, of the thylakoid membrane are not the reason for the chilling lability of net photosynthesis in the intact plant. This conclusion follows from detailed comparison between photosynthetic membranes isolated from prechilled plants and the effects of chilling exposure on CO₂ fixation of the whole plant. Damage at the level of the thylakoid membrane does occur, although not to the extent where it can account for the proportionally much larger damage to CO₂ fixation.     

Rates of Progress towards Flowering and Podding in Bambara Groundnut (Vigna subterranea) as a Function of Temperature and Photoperiod

The influence of temperature and photoperiod on phenologicaldevelopment of three bambara groundnut (Vigna subterranea) selectionsfrom Botswana, Zimbabwe and Mali was investigated in a semi-controlledenvironment experiment with factorial combinations of threeconstant temperatures (20.9, 23.4 and 26.2 °C) and fourconstant photoperiods (10.0, 12.5, 13.5 and 16.0 h d^-1). Inall three selections, the onset of flowering was influencedby temperature but not by photoperiod, while the onset of pod-growth(‘podding’) of all three selections was influencedby both factors. The influence of temperature and photoperiodwas quantified by means of photothermal models, linking developmentrates to temperature and photoperiod with linear equations.The rate of progress from sowing to flowering of the three selectionscould be described very well (r²>95%) as a function of temperature;the rate of progress from flowering to podding was describedreasonably well as a function of both temperature and photoperiodby a combination of one to three response planes (r²for thedifferent selections ranging from 63 to 90%). Model testingwith independent data sets showed good agreement between observedand predicted times to flowering and podding. Vigna subterranea; Voandzeia subterranea; bambara groundnut; phenology; development; flowering; podding; photoperiod; temperature; modelling     

SENSORY AND INSTRUMENTAL FLAVOR ANALYSES OF CHEESE CURD COCULTURED WITH SELECTED YEAST AND BACTERIA

Relationships between odor properties and volatile chemical composition were explored on 39 cocultures of three different yeasts, three Geotrichum candidum and five bacteria, commonly used in bacteria and mold surface ripened cheese. Sensory profiling was performed by ten trained judges by scoring the intensity of 14 odor attributes. At the same time, the volatile compounds of the cocultures were extracted and analyzed by dynamic headspace gas chromatography and mass spectrometry. Sensory and instrumental data were compared and correlated using correlation analysis and partial least squares regression analysis. The sample plot including the whole set of samples evidenced a clustering of the associations containing the yeast strain Kluyveromyces lactis and any bacteria. They developed strong fruity olfactory notes related to their high content of ethyl esters and various alcohols. The sample plot on a restricted set of samples evidenced the fruity characteristics of Debaryomyces hansenii and bacteria associations and the cheesy odors of Yarrowia lipolytica and Geotrichum candidum cocultures that produced sulfur compounds.