Microscopic anatomy of the ovary ofAlouatta caraya

The microscopic structure of theAlouatta caraya ovary is studied in different ages and reproductive stages. The most significant feature seems to be the presence in adult ovaries of abundant glandular interstitial tissue which occupies both the cortex and medulla. It seems to be derived from the theca interna of atretic follicles. Discrete luteinized masses are present in the medulla in all the ovaries observed. Invaginations of the surface epithelium are seen only in infant and juvenile ovaries. The development of cystic follicles seems to be a common pathway of atresia.     

A missense mutation (G197→A) in theα-l-fucosidase gene of fucosidosis patients leads to loss ofα-l-fucosidase

Fucosidosis is an autosomal recessive lysosomal storage disease resulting from the absence of -l-fucosidase activity. Two natural missense mutations (G¹⁹⁷A) and (A⁸⁶⁰G) within the -l-fucosidase gene have been reported to be homozygous in four patients with fucosidosis. Expression of wild-type and mutated -l-fucosidase cDNAs in COS-1 cells revealed complete deficiency of -l-fucosidase for the G¹⁹⁷A transition and a normal level of enzyme for A⁸⁶⁰G. We therefore conclude that the change of G¹⁹⁷A is responsible for fucosidosis in the patients while A⁸⁶⁰G is a normal polymorphic variant of -l-fucosidase.     

Growth promotion and inhibition by antibiotic-producing fluorescent pseudomonads on citrus roots

Summary Forty-three strains of feeder root colonizing fluorescent pseudomonads from rough lemon (Citrus jambhiri Lush.) roots were examined for effects on rough lemon and sweet orange (Citrus sinensis Osbeck) seedlings. Plants inoculated with a single bacterial soil-drench had, after 10 months, a range of stimulatory (to 116%) and inhibitory effects (to 52%). Stimulatory bacteria particularly increased growth of root systems. Cultivar-specific inhibition and stimulation was evident in inoculations of rough lemon and sweet orange seedlings. Populations of fluorescent rhizobacteria on inoculated and noninoculated, as well as on stimulated and nonstimulated seedlings, did not differ significantly (10.8×10⁶ to 30.3×10⁶ CFU/g root). Population of fluorescent rhizobacteria on seedlings were higher than populations on feeder roots from grove trees (2.8 to 5.7×10⁶ CFU/g). Ninety-four and 81% of 251 fluorescent strains produced antibiotics against the fungusGeotrichum candidum and the bacteriumErwinia stewartii, respectively. Antibiotic activities of 90% of the antibiotic producing strains were repressed by Fe³⁺, indicating siderophore production. In comparison, only 9.6 and 15% of 94 randomly selected nonfluorescentPseudomonas strains were antibiotic producers. Differences between stimulatory and inhibitory or neutral bacteria were not apparent from antibiosis tests. On the basis of physiological tests,Pseudomonas putida was the most abundant (>62%) pseudomonad species on rough lemon roots. Growth stimulating strains appeared to be in bothP. putida andP. fluorescens groups. FewP. aeruginosa strains were identified on citrus roots.Florida Agricultural Experiment Stations Journal Series No.     

Qualitative dynamics of three species predator-prey systems

Summary A qualitative analysis of some two and three species predator-prey models is achieved by application of the method of averaging in conjunction with a Lyapunov function constructed from the appropriate Volterra-Lotka model. We calculate the limit cycle solution for a two-species model with a Holling type functional response of the predator to its prey by means of a time-scaled transformation. The existence of a bifurcation of steady states for a community of three species is discussed and the periodic solution around one of the unstable steady states is calculated to the lowest approximation. Several comments are made regarding the behavior of these systems under changes of some control parameters.This work was supported in parts by USERDA, Contract number E(11-1)-3001.     

Regulation of the synthesis of human chorionic gonadotropin by strains of HeLa cells in culture

Summary Thirty-seven strains of HeLa cells were examined for their ability to synthesize human chorionic gonadotropin (hCG) and its alpha subunit (hCG-α) in culture. Synthesis of hCG-α and hCG also was investigated in the presence of sodium butyrate and 5-bromo-2′-deoxyuridine (BrdUrd). All HeLa strains synthesized hCG-α in culture. Sodium butyrate increased the synthesis of hCG-α in all HeLa cells; BrdUrd increased synthesis in 32 of the 37 strains examined. Although few HeLa strains synthesized hCG in the absence of inducers, hCG was detected in most strains in the presence of sodium butyrate. The synthesis of hCG and its alpha subunit is, therefore, a stable genetic characteristics of HeLa cells. Certain preparations of hCG and its subunits were generously provided through the Center for Population Research of the National Institute of Child Health and Human Development, NIH.     

An Artifact Of Liquid Emulsion Autoradiography

The localization of ³H-opiatcs in the myenteric plexus of the guinea pig ileum is subject to systematic artifact when stretch preparations of the myenteric plexus are dipped into liquid Kodak NTB-3 emulsion for autoradiography. The cause of the artifact was determined to be a discontinuous distribution, or retraction, of emulsion over plexuses. The apposition of frozen freeze-dried ilial sections to dried photographic emulsion avoids this source of error.     

The peritrophic membrane in adult simuliids (Diptera) before and after feeding on blood and blood-sucrose mixtures

A peritrophic membrane formed in the posterior midgut of female simuliids of seven species within 30 min of feeding on blood of various avian or mammalian hosts, and 6–12 hr thereafter it displayed up to seven concentric laminae. Within the first 48 hr of blood digestion, the posterior part of the peritrophic membrane (where digestion was most advanced) began to decompose and PM disappearance was complete at the end of blood digestion. In different species blood digestion at 18°–20° required 120–180 hr which was increased to over 200 hr by microsporidan infection. If a blood-sucrose mixture went directly to the midgut, a thin membrane formed around it, but not if it went indirectly by way of the crop. A prefeeding secretion in the anterior midgut is considered to be the peritrophic membrane of the pharate adult surrounding a small, but variable, amount of material, the meconium.

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Résumé Sept espèces de simulies ont été étudiées: 5 ornithophiles, 2 mammalophiles. Trente minutes après un repas de sang sur divers oiseaux (poulet, canard) ou mammifères (homme, cerf, élan d'Amérique) on constate qu'une membrane péritrophique est sécrétée par toute le surface épithéliale dans la région moyenne de l'intestin moyen postérieur dilaté des femelles. Six à douze heures après le repas cette membrane comporte jusqu'à sept lamelles concentriques. Une sécrétion moins importante se forme autour de la petite quantité de sang que l'on trouve dans l'estomac antérieur, non dilaté et étroit; cette sécrétion glisse vers l'arrière et forme une capsule recouvrant le pôle antérieur du bol alimentaire sanguin dans la partie postérieure de l'intestin moyen, ceci pendant le premier jour. La digestion commence à la périphérie et à l'extrémité postérieure de la masse sanguine et se poursuit enfin à l'extrémité antérieure, où la membrane péritrophique conserve le plus longtemps sa structure en contact avec le sang non digéré. Dans les premières 48 heures de la digestion du sang, la région postértieure de la membrane péritrophique (là où la digestion est la plus avancée) commence à se décomposer, et sa disparition est complète quand la digestion du sang est achevée. Chez les différentes espèces étudiées, la digestion du sang à 18–20° exige 120–180 heures, pouvant demander plus de 200 heures chez des insectes atteints d'une infection par des microsporidies. Si un mélange de sang et sucrose parvient directement dans la région moyenne de l'intestin moyen, une membrane mince se forme autour, mais non si cet aliment passe par le jabot. Une sécrétion précédant l'alimentation s'observe dans l'intestin moyen antérieur des mouches non nourries et doit représenter, chez l'adulte venant d'éclore, la membrane péritrophique entourant le méconium: petite quantité de matière d'importance variable. Cette matière se retrouve souvent au centre de la masse sanguine après alimentation et est lente à digérer.

     

A four-iron, four-sulfide ferredoxin with high thermostability from Clostridium thermoaceticum.

A ferredoxin containing only one [Fe4S4] cluster was purified from Clostridium thermoaceticum. It has a molecular weight of about 7,300, a partial specific volume of 0.67, and an isoelectric point of 3.25. Its absorption spectrum has two maxima at 390 nm (epsilon = 16.8 X 10(3)M-1cm-1) and at 280 nm (epsilon = 24.2 X 10(3)M-1cm-1). The absorption at 390 nm is almost half that of other clostridial ferredoxins, which have two [Fe4S4] clusters, and is similar to other ferredoxins with only one [Fe4S4] cluster. The ferredoxin had high thermal stability and retained over 50% of its activity after treatment at 80 degrees C. It functions in the transfer of electrons from pyruvate to nicotinamide adenine dinucleotide phosphate (NADP), which indicates the presence of pyruvate:ferredoxin oxidoreductase and reduced ferredoxin-NADP reductase in C, thermoaceticum. NADPH is used in the synthesis of acetate from CO2 in this organism.     

Proton transport by bacteriorhodopsin through an interface film

Summary Interface films of purple membrane and lipid containing spectroscopically intact and oriented bacteriorhodopsin have been used as a model system to study the function of this protein. Small positive charges in surface potential (<1 mV) are detected upon illumination of these films at the air-water interface. These photopotentials, are not affected by overlaying the interface film with a thin layer (0.3 mm) of decane. However, they are dramatically increased when lipid soluble proton carriers FCCP or DNP are added to the decane. The polarity of the photopotential indicates that, in the light, positive charges are transported through the interface from the aqueous to the organic phase. The action spectrum of the photopotential is identical to the absorption spectrum of bacteriorhodopsin. Since bacteriorhodopsin molecules are oriented with their intracellular surface towards the aqueous subphase, the characteristics of the photopotential indicate that in the light bacteriorhodopsin translocates protons from its intracellular to its extracellular surface. The kinetics of the photopotential reveal that the rate and extent of proton transport are proportional both to the fraction of bacteriorhodopsin molecules excited and to the concentration of proton acceptor. The photopotentials result from changes in the ionic distribution across the decane-water interface and can be cancelled by lipid soluble anions.     

Resolution of optical isomers by high-pressure liquid chromatography: The separation of benzo[a]pyrene trans-diol derivatives

The optical isomers of (±)r-7,t-8-dihydroxy-7,8-dihydrobenzo[a]pyrene and its synthetic precursor (±)r-7,t-8-dihydroxy-7,8,9,10-tetrahydrobenzo[a]pyrene were resolved as their di-(−)menthoxyacetates using high-pressure liquid chromatography. Saponification of the resolved diesters yielded the corresponding enantiomers. The specific rotation, CD spectra, and ORD curves are reported. The resolution of these optical isomers permits detailed studies on the enzymatic intermediates and the mechanism of benzo[a]pyrene activation to its carcinogenic form. The method is of general usefulness for the resolution of optical isomers.