Optimum temperature for egg development of phenotypes in Haemonchus contortus cayugensis as determined by Arrhenius diagrams and Sacher's entropy function

Lejambre L. P. and Whitlock J. H. 1973. Optimum temperature for egg development of phenotypes in Haemonchus contortus cayugensis as determined by Arrhenius diagrams and Sacher's entropy function. International Journal for Parasitology3: 299–310. Oxygen uptake, maturation time and percentage hatch were determined on eggs from “wild-type” Haemonchus contortus cayugensis populations as well as those from the morph types smooth, linguiform B and linguiform A. Sacher's organizational entropy, which is essentially a sum of oxygen utilized by a system corrected for the number of viable units in the system, was used to determine the optimum temperature for development of the eggs. Although the eggs from “wild-type” H. contortus cayugensis hatched well across a broad temperature range; individual phenotypes showed a much narrower range. The optimum temperature for the development of eggs from smooth worms was approximately 30°C while linguiform A and B hatched best at 25°C. Linguiform A eggs had a broader temperature tolerance than linguiform B so that at temperatures of 17°C they hatched with a greater efficiency than did either smooth or linguiform B. It is argued that H. contortus follows a “strategy” of having many phenotypes, each one of which appears to be adapted to a different temperature. This would allow a population to maintain a broad range of optimal temperatures without the expense of maintaining the cybernetic machinery which a single individual would have to have if it were to tolerate the same range of temperature.     

Genetics of vulvar morph types in Haemonchus contortus: Haemonchus contortus from the Northern Tablelands of New South Wales

Le Jambre L. F. and Royal W. M. 1977. Genetics of vulvar morph types in Haemonchus contortus: Haemonchus contortus from the Northern Tablelands of New South Wales. International Journal for Parasitology7: 481–487. The inheritance of the vulvar morph types, smooth, knobbed, linguiform A-right, linguiform A-left and linguiform C-type was studied in Haemonchus contortus from the Northern Tablelands of New South Wales. The dominance hierarchy of these characters was found to be smooth > knobbed > linguiform. The linguiform phenotype was the most common in the wild type population. The modifications on the linguiform phenotype were found to be highly heritable with A-right responding most to selection. Realised heritabilities for these characters was A-right 0.37, A-left 0.15, and C-type 0.21. It appeared that the dominance of a phenotype increased following selection.     

The mechanism of energy conservation and transduction by mitochondrial cytochrome c oxidase

Oxidation of ferrocytochrome c by molecular oxygen catalysed by cytochrome c oxidase (cytochrome aa₃) is coupled to translocation of H⁺ ions across the mitochondrial membrane. The proton pump is an intrinsic property of the cytochrome c oxidase complex as revealed by studies with phospholipid vesicles inlayed with the purified enzyme. As the conformation of cytochrome aa₃ is specifically sensitive to the electrochemical proton gradient across the mitochondrial membrane, it is likely that redox energy is primarily conserved as a conformational “strain” in the cytochrome aa₃ complex, followed by relaxation linked to proton translocation. Similar principles of energy conservation and transduction may apply on other respiratory chain complexes and on mitochondrial ATP synthase.     

Genetics of vulvar morph types in Haemonchus contortus: Haemonchus contortus cayugensis from the finger lakes region of new york

The inheritance of the four most common morph types (smooth, knobbed, linguform A and B) in Haemonchus contortus cayugensis was studied by selection of offspring from females of known morph type and also by mating males from an inbred strain of linguiform A with smooth and linguiform B females. The dominance hierarchy of these characters was found to be linguiform > knobbed > smooth. Linguiform B was recessive to linguiform A but neither character is expressed in the presence of the smooth morph type.     

Control of respiration in proteoliposomes containing cytochrome aa3 II. Inhibition by carbon monoxide and azide

1. Carbon monoxide (CO) acts competitively towards oxygen when the latter is taken up in respiration by cytochrome aa₃-containing proteoliposomes, both in the presence of p-trifluoromethoxy carbonyl cyanide phenylhydrazone and valinomycin (deenergized state) and in their absence (energized state). At high levels of CO, the double reciprocal plots ($\text{1}\text{v}$ vs. $\text{1}\text{[}\text{O}{}_2\text{]}$) in the energized and deenergized states are parallel, i.e. energization acts “anti-competitively” towards oxygen, and the “respiratory control ratio” decreases as the oxygen concentration decreases.2. Azide acts non-competitively towards cytochrome c when the latter is oxidized by cytochrome aa₃-containing proteoliposomes both in the energized and deenergized (plus p-trifluoromethoxy carbonyl cyanide phenylhydrazone and valinomycin) conditions. At low azide concentrations the apparent K_i for azide is unaffected by energization, but at high azide levels the K_i increases in energized liposomes, i.e. the “respiratory control ratio” decreases as the azide concentration increases.3. It is concluded that the inhibitor experiments are consistent with but do not prove the concept that the oxidase molecules in a single vesicle are responding to a single “energization state” or set of electrochemical gradients. This and other models are discussed.     

Decomposition and nutrient dynamics of marsh litter in the Sanjiang Plain, Northeast China

The litterbag technique was used to study the decomposition and nutrient dynamics of marsh litter in the four communities, Carex pseudocuraica (C.pa), C. lasiocarpa (C.la), Deyeuxia angustifolia (D.aa), and D. angustifolia-Shrub (D.aa-Srb), in Sanjiang Plain, Northeast China. Decomposition was divided into two periods in the first year, with the mass loss ranging from 11.7% to 31.4% of the initial mass during summer and autumn, accounting for more than 75% of the annual loss. The decomposition rates ranged from 0.000 612 to 0.000 945 d^-1 depending on the depth of the flooding and its duration, and differed significantly in each community. The litter decomposed faster in communities with deeper and perennial flooding than in those with shallow and seasonal flooding. The initial ratios of C:N and C:P were also different among the four litter types, but these differences had no impact on the decomposition rates, suggesting that the main factor influencing the decomposition rates of marsh litter was the flooding status rather than the litter quality. The N concentrations in C.pa and C.la almost continuously increased over time, with their final values being 2.8 and 2.4 times higher than the initial ones, respectively. However, the nutrient dynamics in D.aa and D.aa-Srb offered another pattern, sharply falling in the first month and then gradually rising, with the values at the end of the experiment being close to those at the beginning. The litter accumulated substantial amounts of N in C.pa and C.la, while net N release from the litter was observed in both D.aa and D.aa-Srb. The difference may be caused by microorganisms' demand for nutrition, and then limited by the C:N ratios of litter and the availability of nitrogen from the soil and marsh water. In contrast with N dynamics, P concentrations of all the litter types apparently decreased during the first month, and then continued to decline in C.pa, remained constant in C.la and D.aa and increased slightly in D.aa-Srb. At the end of the experiment, the P concentrations decreased, respectively, by 56%, -5%, 47% and 24% of the initial values of C.la, C. pa, D.aa and D.aa-Srb. The net P release was observed in all marsh litter over 480 days of decomposition and the intensity of the P release was different amongst communities, which may be regulated by ratios of initial C:P. The results suggested that in the marsh with the N limitation, litter tended to accumulate N and release P during decomposition and the intensity of accumulation or release was closely related to the initial C:N and C:P ratios.     

Structural basis for RKIP binding with its substrate Raf1 kinase

Raf1 kinase inhibitor protein (RKIP) negatively regulates the Raf1/MEK/ERK pathway which is vital for cell growth and differentiation. It is also a biomarker in clinical cancer diagnosis. RKIP binds to the N-terminus of Raf1 kinase but little is known about the structural basis of RKIP binding with Raf1. Here, we demonstrate that the N-terminus of human Raf1 kinase (hRaf1_1-147aa) binds with human RKIP (hRKIP) at its ligand-binding pocket, loop “127–149”, and the C-terminal helix by NMR experiments. D70, D72, E83, Y120, and Y181 were further verified as the key residues participating in the interaction of hRKIP and hRaf1_1-147aa. G143-R146 fragment was also critical for hRKIP binding with hRaf1_1-147aa, for its deletion decreased the binding affinity around 300 times, from 154 to 0.46 mM^?1. Our results provide important structural clues for designing the lead compound that disrupts RKIP–Raf1 interaction.     

A vector method of representation of enzymic reactions: 1. Parametric classification of types of enzymic reaction

A new “parametric” classification of the types of single-substrate enzymic reactions is proposed that includes 15 different types: seven inhibited, seven activated and one initial (uninhibited, i=0 and nonactivated, a=0). The new classification takes into account both the “parametricity” of these reactions and the mechanisms of their action. It unites all the types in an original symmetric system which vividly demonstrates the interconnection between separate (strictly definite) types of inhibited and activated enzymic reactions. The proposed classification permits the revision and some corrections to traditional “competitive” terminology as well as the application of these ideas and mathematical approaches pertinent to the calculation of reactions of enzyme inhibition for data analysis of enzyme activation.     

Molecular Characterization of Branchial aquaporin 1aa and Effects of Seawater Acclimation,Emersion or Ammonia Exposure on Its mRNA Expression in the Gills,Gut, Kidney and Skin of the Freshwater Climbing Perch,Anabas testudineus

We obtained a full cDNA coding sequence of aquaporin 1aa (aqp1aa) from the gills of the freshwater climbing perch, Anabas testudineus, which had the highest expression in the gills and skin, suggesting an important role of Aqp1aa in these organs. Since seawater acclimation had no significant effects on the branchial and intestinal aqp1aa mRNA expression, and since the mRNA expression of aqp1aa in the gut was extremely low, it can be deduced that Aqp1aa, despite being a water channel, did not play a significant osmoregulatory role in A. testudineus. However, terrestrial exposure led to significant increases in the mRNA expression of aqp1aa in the gills and skin of A. testudineus. Since terrestrial exposure would lead to evaporative water loss, these results further support the proposition that Aqp1aa did not function predominantly for the permeation of water through the gills and skin. Rather, increased aqp1aa mRNA expression might be necessary to facilitate increased ammonia excretion during emersion, because A. testudineus is known to utilize amino acids as energy sources for locomotor activity with increased ammonia production on land. Furthermore, ammonia exposure resulted in significant decreases in mRNA expression of aqp1aa in the gills and skin of A. testudineus, presumably to reduce ammonia influx during ammonia loading. This corroborates previous reports on AQP1 being able to facilitate ammonia permeation. However, a molecular characterization of Aqp1aa from A. testudineus revealed that its intrinsic aquapore might not facilitate NH₃ transport. Hence, ammonia probably permeated the central fifth pore of the Aqp1aa tetramer as suggested previously. Taken together, our results indicate that Aqp1aa might have a greater physiological role in ammonia excretion than in osmoregulation in A. testudineus.     

Evidence for gene inactivation in the virus-induced aberrant ratio phenomenon in maize

Reciprocal crosses were made between pairs of plants showing the "aberrant ratio" (AR) effect at the a locus, and simultaneously between these plants and an aa tester. The results suggested that the AR effect in the particular line that was used could be explained by inactivation of a gene other than A, but also required for aleurone color. Segregation ratios in additional crosses largely fit expectations predicted on the basis of this hypothesis.     

Migratory history of Rhinogobius sp. OR morphotype “Shimahire” as revealed by otolith Sr:Ca ratios

The migratory history of the Rhinogobius sp. OR morphotype “Shimahire” collected from a slower current environment in the Maruyama River, the Ibo River, and the Kako River, Japan, was studied by examining the strontium and calcium concentrations in the otoliths. The otolith Sr:Ca ratios of almost all samples showed consistently low ratios from the core to the edge, reflecting the fact that the organisms had been living in a freshwater environment their entire lives. The ratios of Rhinogobius sp. CB and Rhinogobius flumineus living in the sympatric habitats with the Rhinogobius sp. OR morphotype “Shimahire” in the Kako River showed an amphidromous and fluvial life cycle, respectively. These findings suggest that the Rhinogobius sp. OR morphotype “Shimahire” has a freshwater resident life cycle.     

Derepression of mitochondria and their enzymes in yeast: regulatory aspects

We have performed a detailed analysis of the properties of glucose-repressed cells of a commercial strain of Saccharomyces cerevisiae. They contain measurable amounts of the respiratory enzymes NADH oxidase, cytochrome c oxidase, succinate dehydrogenase, succinate:cytochrome c reductase and NADH:cytochrome c reductase (antimycin A-sensitive) as well as the dehydrogenases for l-malate, l-glutamate, and l₈-isocitrate. Cytochromes b, c₁, and aa₃ are present in amounts that may be in excess of those required for cytochrome-linked enzyme activities. Enzymes and cytochromes are localized in large, presumably mitochondrial organelles among which no compositional or functional heterogeneity could be detected.We have also analyzed the kinetics of synthesis of respiratory enzymes and cytochromes during the release from catabolite(glucose) repression. All activities assayed except for cytochrome c oxidase begin their derepression before the external glucose concentration falls below 0.4%; derepression of cytochrome oxidase occurs only after the glucose concentration falls below 0.1%. The earlier events comprise the “fermentative” phase of derepression while the later events comprise the “oxidative” phase. The two phases can be distinguished operationally by their sensitivity to antimycin A. Only the oxidative phase is blocked by the inhibitor. Respiratory enzymes and cytochromes appear to fall into two classes distinguishable by their increase during derepression. An apparently constitutive one consists of cytochrome c oxidase, ATPase, and cytochromes aa₃, b, and c₁; these entities increase in amount per cell but not in amount per unit of mitochondrial mass and are of the order of 5-fold or less. The second class consists of those activities that increase by more than 6-fold and may be considered derepressible in the strict sense. Thus, proliferation and differentiation of mitochondria both contribute to the cellular changes associated with derepression.The fermentative phase of derepression does not require mitochondrial function, mitochondrial protein, or RNA synthesis, or the gradual accumulation of regulatory elements for either its initiation or persistence. This phase of derepression also occurs in cytoplasmic petites. In contrast, the oxidative phase of derepression requires mitochondrial function. Mitochondrial gene expression is required for the biogenesis of fully functional mitochondria but, except for cytochrome c, it plays little or no role in regulating the expression of nuclear genes the products of which are localized in mitochondria.     

Pearl mussels of the genus Dahurinaia (Bivalvia,Margaritiferidae): Differently sized groups of Margaritifera dahurica Middendorff, 1850

Molecular and genetic studies have revealed that all five species of pearl mussels of the genus Dahurinaia (Bivalvia, Margaritiferidae) inhabiting the upper basin of the Amur River on the territory of Transbaikalia belong to Margaritifera dahurica Middendorff, 1850. Based on the statistical analysis, it has been shown that morphometric shell ratios form continuous variation series without differentiation on discrete groups. It has been found that changes in these ratios are caused by the shell growth of pearl mussels and their morphological variations reflects the high level of polymorphism. The so-called “comparator” species of the genus Dahurinaia are differently sized groups of one polymorphic biological species M. dahurica.     

The pre-steady state reaction of ferrocytochrome c with the cytochrome c-cytochrome aa3 complex

1. Using stopped-flow technique we have investigated the electron transfer form cytochrome c to cytochrome aa₃ and to the (porphyrin) cytochrome c-cytochromeaa₃ complex.2. In a low ionic strength medium, the pre-steady state reaction occurs in a biphasic way with rate constants of at least 2 · 10⁸ M^?1 · s^?1 and about 10⁷ M^?1 · s^?1 (I = 8.8 mM, pH 7.0, 10° C), respectively.3. A comparison of the rate constants, determined in the presence of an excess of cytochrome c with those found in the presence of an excess of cytochrome aa₃ reveals the existence of two slower reacting sites on the functional unit (2 hemes and 2 coppers) of cytochrome aa₃. On basis of these results we discuss various models. If no site-site interactions are assumed (non-cooperative model) cytochrome aa₃ has 2 high and 2 low affinity sites available for the reaction with ferrocytochrome c. If negative cooperativity occurs, cytochrome aa₃ has 2 high affinity sites which change into 2 low affinity sites upon binding of one cytochrome c molecule. The latter model is favoured.     

Formalized analysis of associativity of morphogenetic types and humus condition of ground litter in marsh birch forests

There are six morphogenetic types of forest ground litter in the gradient of big grass-sphagnous-dead litter marsh birch forest: deeply degraded litter, half degraded litter, rhizomatous litter (coarsely degraded), peaty litter, turfy-formed litter, and turfy litter. The specificity of their biochemical transformations is caused by the accumulation of humic acids (HA), especially of the first fraction (HA-1), alongside the relatively steady background formation of fulvic acids. The C/N value suggests that the intensity of HA-1 formation is closely associated with the biological activity of the substrate. However, the indistinct difference of these parameters in the forestry-morphological types of litters limits their diagnostic reliability. Grouped biochemical types of litters, such as “soft” (half- and deeply degraded), “intermediate” (rhizomatous, peaty and turfy-formed), and “coarse” (mossy), are considerably discriminated by both the C/N ratio (20, 30, 40) and the level of HA-1 (14, 10, and 6%) respectively.     

Ultrastructural pattern of the nucleus of Entamoeba coli

The ultrastructural organization model of the nucleus of Entamoeba coli, as outlined on the basis of our electron microscope research, shows the following characteristics: (1) karyosome located eccentrically in the nucleoplasm (in the equatorial sections of the nucleus), the heterochromatin laid out in rough, tangled sinuous bands; (2) “ball of thread-like” formations at the level of the heterochromatin border; and (3) circular dark bodies falling into two morphological types on account of their size, the “larger inclusions” type being morphologically similar to the “button bodies” of Entamoeba histolytica according to Ludwik &; Shipstone (1970). Characteristic organized clumps of these structures have not been described before and are especially evident in the cystic nuclei. These findings are discussed in relation to the nuclear organization pictures given by E. histolytica, E. moshkovskii, and E. invadens under the electron microscope.     

Evolution of photosynthetic reaction centers

The common ancestor of all photosynthetic prokaryotes and organelles contained chlorophyll (Chl) a. All green and purple photosynthetic bacteria descended from a common bacteriochlorophyll (Bchl) a-containing ancestor which diverged from the Chl a line. Separate PS-I and PS-II reaction centers may have evolved before the appearance of Bchl a. When the transition to Bchl a occurred, the resultant organism contained two types of reaction center, “PS-I” and “PS-II.” One line of development eliminated “PS-II” and evolved into the green bacteria. The other line eliminated “PS-I” and became the purple bacteria. In the Chl a-containing organisms the evolution of PS-II continued until oxygen evolution was achieved.     

Microsymbionts of Phaseolus vulgaris in acid and alkaline soils of Mexico

In order to investigate bean-nodulating rhizobia in different types of soil, 41 nodule isolates from acid and alkaline soils in Mexico were characterized. Based upon the phylogenetic studies of 16S rRNA, atpD, glnII, recA, rpoB, gyrB, nifH and nodC genes, the isolates originating from acid soils were identified as the phaseoli symbiovar of the Rhizobium leguminosarum-like group and Rhizobium grahamii, whereas the isolates from alkaline soils were defined as Ensifer americanum sv. mediterranense and Rhizobium radiobacter. The isolates of “R. leguminosarum” and E. americanum harbored nodC and nifH genes, but the symbiotic genes were not detected in the four isolates of the other two species. It was the first time that “R. leguminosarum” and E. americanum have been reported as bean-nodulating bacteria in Mexico. The high similarity of symbiotic genes in the Rhizobium and Ensifer populations showed that these genes had the same origin and have diversified recently in different rhizobial species. Phenotypic characterization revealed that the “R. leguminosarum” population was more adapted to the acid and low salinity conditions, while the E. americanum population preferred alkaline conditions. The findings of this study have improved the knowledge of the diversity, geographic distribution and evolution of bean-nodulating rhizobia in Mexico.     

Haemonchus contortus: Immunodiffusion patterns of antigens from phenotypically different females

Immunodiffusion patterns of the different morphological types of female Haemonchus contortus (Rudolphi, 1803) indicate that the three phenotypes—smooth, linguiform, and knobbed—differ from each other serologically. Linguiform antigens gave five precipitin lines, knobbed gave four lines, and smooth gave three precipitin lines with rabbit antisera. Also, lines unite in a manner indicating marked antigenic differences between the three types. Since serological studies are considered to be sensitive tools in taxonomy, the present work indicates that taxonomic importance should be attached to the vulvar configurations in female H. contortus.