A/California/7/2009与A/California/4/2009病毒感染力比较

目的甲型H1N1流感病毒A/California/7/2009与A/California/4/2009病毒序列比较同源性在99%以上,本实验旨在比较两株病毒感染BALB/c小鼠研究感染力强弱。方法分别将A/California/7/2009（CA7）与A/California/4/2009（CA4）两株病毒分别连续10倍稀释后,对4~6周龄雌性BALB/c小鼠经乙醚麻醉后进行滴鼻攻毒,每个稀释度接种10只实验小鼠,测定CA7 MLD50为101.24/0.05 mL,检测小鼠感染、致病的多项指标,观察期为14 d。结果相同TCID50的CA7和CA4病毒感染小鼠,CA4感染小鼠后14 d内死亡率为20%,而CA7感染小鼠后8 d内死亡率为100%。CA7 106TCID50感染的小鼠病理表现为重度弥漫性间质性肺炎,CA4 106TCID50感染的小鼠病理表现为中度-重度间质性肺炎。结论在相同条件下,CA7感染力明显强于CA4。     

Preparation of copoly (γ-benzyl-l-glutamyl-N5-β-d-glucopyranosyl-l-glutamine) and its interaction with fibroblast cells

Copoly(α-amino acid)s consisting of γ-benzyl-l-glutamate and $\text{N}{}^5\text{-β-}\text{d}\text{-glucopyranosyl-}\text{l}\text{-glutamine}$ were prepared by the reaction of copoly(l-glutamate) containing succinimide ester, which served as active site for the coupling reaction with β-d-glucopyranosylamine. The α-helical conformation of these copolymers became unstable in DMF as the content of glutamine derivative increased. A dry film made from this copolymer could take a full α-helical conformation even at such a high content as 80% of the glutamine derivative, but in a wet film this ordered structure was partially disrupted by hydration. The hydraulic permeability of this copoly(α-amino acid) was clearly dependent on the molar content of glucopyranosyl groups. The attachment of fibroblast cells to these hydrated copolymer films was effectively depressed in the presence of a serum-free medium. The cells attached to the substrate were spherical in shape.     

Metabolism of Δ4-cis-PGF1α in the monkey

This isomer of PGF_2α is relatively resistant to metabolic degradation in the Cynomolgus monkey. Thus, 16–20 per cent of the amount injected was excreted unchanged in the urine. Five metabolites with 20, 18, 16 and 14 carbon atoms in the skeleton were identified. The data are similar to those earlier seen in the rat and further support the idea that this analogue of PGF_2α could have a long half-life time in the mammalian body and thus a long duration of its pharmacological actions.     

Conformational studies on poly(N-δ-trimethyl-l-ornithine)

$\text{Poly}\text{(N-δ-}\text{trimethyl-}\text{l}\text{-ornithine}$), (Me₃Orn)_n, is usually not able to attain the α-helical conformation in aqueous solution independent of its pH value; however, it becomes α-helical at low concentrations of sodium perchlorate over a wide pH range according to the circular dichorism (c.d.) spectra. Cl^?, SO₄^2? and H₂PO₄^? do not induce α-helix formation. One can conclude that a distinct topology of the anions bound by the side chains is responsible for the α-helix-inducing effect of some water-structure-breaking anions such as perchlorate. This means that the anions are inserted between the ?N⁺ of the side groups shielding the positive charges repelling one another. The insertion of the anions requires that the water molecules surrounding the ions can be stripped off, which is easily possible if they are water-structure-breaking ones. At higher perchlorate concentrations, the c.d. spectrum changes. It is characterized by a negative shoulder near 208 nm and a pronounced minimum at ≈ 226 nm. With increasing temperature, the c.d. spectrum of the α-helix occurs. Finally the α-helix undergoes a conformational change to the random coil. The apparent transition enthalpy ΔH_vH is remarkably lower than that of the homologue (Me₃Lys)_n, obviously due to a lower cooperativity of the transition. In contrast to poly(l-ornithine), (Orn)_n, the c.d. spectrum of (Me₃Orn)_n remains almost unchanged after adding anionic surfactants such as sodium octyl sulphate (SOS) or sodium dodecyl sulphate (SDS). In organic solvents like methanol or isopropanol, in contrast to (Orn)_a and (Lys)_n, no α-helix formation occurs. However, in mixtures of these alcohols or dioxane with water, α-helix formation is induced by perchlorate, as in pure water. The thermal stability of the α-helix in these systems is increased.     

Dissimilatory nitrate uptake in Paracoccus denitrificans via a Δ\̃gmH+-dependent system and a nitrate-nitrite antiport system

Respiration-driven proton translocation has been studied with the oxidant pulse method for cells of denitrifying Paracoccus denitrificans oxidizing H₂ during reduction of O₂, NO^?₃, NO^?₂ or N₂O. A simplified scheme of anaerobic electron transport and associated proton translocation is shown that is consistent with the measured $\text{H}{}^{\mathrm{+}}\text{oxidant ratios}$. Furthermore, the kinetics and energetics of NO^?₃ uptake in whole cells of P. denitrificans were studied. For this purpose, we measured H₂ consumption or N₂O production after addition of NO^?₃ to a cell suspension, which indirectly gave information about uptake (and reduction) of NO^?₃. It was found that a lag phase in H₂ consumption or N₂O production appeared whenever the membrane potential was dissipated by addition of thiocyanate, carbonyl cyanide m-chlorophenylhydrazone or triphenyl-methylphosphonium bromide. However, these lag phases were not observed when NO^?₂ was present at the moment of introduction of NO^?₃. On the basis of these findings we conclude that there are two uptake systems for NO^?₃. One system is dependent on the proton-motive force and is probably used for initiation of NO^?₃ uptake. The other is an $\text{NO}{}^{\mathrm{?}}{}_3\text{NO}{}^{\mathrm{?}}{}_2$ antiport and its function is to take over NO^?₃ uptake from the first system.     

Determination of H+e− ratios in chloroplasts with flashing light

Using a rapid pH electrode, measurements were made of the flash-induced proton transport in isolated spinach chloroplasts. To calibrate the system, we assumed that in the presence of ferricyanide and in steady-state flashing light, each flash liberates from water one proton per reaction chain. We concluded that with both ferricyanide and methylviologen as acceptors two protons per electron are translocated by the electron transport chain connecting Photosystem II and I. With methyl viologen but not with ferricyanide as an acceptor, two additional protons per electron are taken up due to Photosystem I activity. One of these latter protons is translocated to the inside of the thylakoid while the other is taken up in H₂O₂ formation. Assuming that the proton released during water splitting remains inside the thylakoid, we compute $\text{H}{}^{\mathrm{+}}\text{e}{}^{\mathrm{?}}$ ratios of 3 and 4 for ferricyanide and methyl viologen, respectively.In continuous light of low intensity, we obtained the same $\text{H}{}^{\mathrm{+}}\text{e}{}^{\mathrm{?}}$ ratios. However, with higher intensities where electron transport becomes rate limited by the internal pH, the $\text{H}{}^{\mathrm{+}}\text{e}{}^{\mathrm{?}}$ ratio approached 2 as a limit for both acceptors.A working model is presented which includes two sites of proton translocation, one between the photoacts, the other connected to Photosystem I, each of which translocates two protons per electron. Each site presents a ≈ 30 ms diffusion barrier to proton passage which can be lowered by uncouplers to 6–10 ms.     

Comparison of red cell and kidney (Na+ + K+)-ATPase at 0°C

Human red cell and guinea pig kidney $\text{(}\text{Na}{}^{\mathrm{+}}\text{+}\text{K}{}^{\mathrm{+}}\text{)-}\text{ATPase}$ were phosphorylated at 0°C. Using concentrations of ATP ranging from 10^?6 to 10^?8 M, ATP-dependent regulation of reactivity is observed with red cell but not kidney $\text{(}\text{Na}{}^{\mathrm{+}}\text{+}\text{K}{}^{\mathrm{+}}\text{)-}\text{ATPase}$ at 0°C. In particular, with the red cell enzyme only, the following are observed: (i) the ratio of enzyme-bound ATP (E·ATP, measured by the pulse-chase method of Post, R.L., Kume, S., Tobin, T., Orcutt, B. and Sen, A.K. (1969) J. Gen. Physiol. 54, 306s-326s) to steady-state level of total phosphoenzyme (EP) decreases with decrease in ATP concentration and (ii) the apparent turnover of phosphoenzyme (ratio of Na⁺-stimulated ATP hydrolysis to level of total EP at steady state) also varies as a function of ATP concentration. In addition, when EP is formed at very low ATP (0.02 μM), and then EDTA is added, rapid disappearance of a fraction of EP occurs, presumably due to ATP resynthesis, only with the red cell enzyme. These differences in behaviour of the red cell and kidney enzymes are explained on the basis of the observed predominance of K⁺-insensitive EP in red cell, but K⁺-sensitive EP in kidney $\text{(}\text{Na}{}^{\mathrm{+}}\text{+}\text{K}{}^{\mathrm{+}}\text{)-}\text{ATPase}$ at 0°C.     

Characterization of a β-actinin-like protein in purified non-muscle cell membranes. Its activity on (Na+ + K+)-ATPase

Treatment by EDTA of purified plasma membranes from MF₂S cells (a variant of the murine plasmacytoma MOPC 173) solubilized proteins and increased by a 1000-fold the sensitivity of $\text{(}\text{Na}{}^{\mathrm{+}}\text{+}\text{K}{}^{\mathrm{+}}\text{)-}\text{ATPase}$ to ouabain. When added back with Ca²⁺ to treated plasma membranes, these EDTA-solubilized proteins restored the initial sensitivity of the enzyme to its inhibitor. We report the purification of a protein of $\text{M}{}_{\mathrm{<mtext>r</mtext>}}$ 32 000, isolated from the EDTA-treated membrane supernatant. This protein was purified by a one-step procedure involving a preparative polyacrylamide gel electrophoresis without detergent. In the presence of Ca²⁺ it was able to restore the original sensitivity to ouabain of $\text{(}\text{Na}{}^{\mathrm{+}}\text{+}\text{K}{}^{\mathrm{+}}\text{)-}\text{ATPase}$ from EDTA-treated membrane. This protein was shown to be similar to the β-actinin described by Maruyama by the following criteria: (1) molecular weight and amino acid composition; (2) cross-reactivity with their respective antisera; (3) in the presence of Ca²⁺ the same quantitative biological activity on ouabain sensitivity of the $\text{(}\text{Na}{}^{\mathrm{+}}\text{+}\text{K}{}^{\mathrm{+}}\text{)-}\text{ATPase}$. A possible interaction between β-actinin, calmodulin and membrane-bound $\text{(}\text{Na}{}^{\mathrm{+}}\text{+}\text{K}{}^{\mathrm{+}}\text{)-}\text{ATPase}$ is discussed.     

Net CI− flux in short-circuited skin of Rana pipiens: Ouabain sensitivity and Na+ + K+ dependence

Skin of Rana pipiens, like many other species, is considered to actively trassport only Na⁺ when bathed in Ringer's solution on both sides. However, net CI^? influx was previously described by us in short-circuited skin of Rana pipiens, in the summer season. The skins were of low PD (5–30 mV) and high CI^? conductance. Comparison of these findings with other series indicated inverse seasonal variation between PD and CI^? conductance. It was postulated that active CI^? transport exists at all CI^?-conductance levels but at higher PD is too small to be be easily detected. This report evaluates CI^? transport across skins of higher PD (and lower conductance) in winter and further characterizes the system. Net CI^? influx was demonstrated over a wide PD range under short-circuit conditions and was inversely related to the magnitude of the open-circuit PD. It was inhibited by ouabain and dependent upon Na⁺ in the outside medium and K⁺ in the inside medium. It is concluded that this is the same system present in skin of Leptodactylus ocellatus and may not be unique to these two species. It appears to be distinctly different from the acetazolamide-sensitive influx system seen in “low-CI^?” solutions in skins of numerous species. The findings are discussed in terms of (1) parallel Na⁺ and CI^? active transport mechanisms and (2) a neutral NaCI-pump model, recently proposed by Rehm.     

The use of 2-O-acyl-1-O-sulfonyl-d-galactopyranose derivatives in β-d-galactopyranoside synthesis

Several 1-O-sulfonyl derivatives of d-galactopyranose having a participating benzoyl or p-methoxybenzoyl group at O-2 were synthesized from the corresponding d-galactopyranosyl chloride derivatives by use of silver p-toluenesulfonate or trifluoroethanesulfonate in acetonitrile. The reaction of the $\text{1-O-}\text{sulfonyl-}\text{d}\text{-galactopyranose}$ derivatives with several alcohols in various solvents at different times and temperatures served as model reactions to determine the best conditions for synthesizing stereoselectively β-d-galactopyranosides in high yields. This method was used to prepare, in good yield, several β-d-galactopyranosyl-containing disaccharides.     

Catalytic properties of the resolved flavoprotein and cytochrome B components of the NADPH dependent O2−• generating oxidase from human neutrophils

The resolved flavoprotein and cytochrome b₅₅₉ components of the NADPH dependent $\text{O}{}_2{}^{\mathrm{?}}{}_{\mathrm{?}}$ generating oxidase from human neutrophils were the subject of further study. The resolved flavoprotein, depleted of cytochrome b₅₅₉, was reduced by NADPH under anaerobic conditions and reoxidized by oxygen. NADPH dependent $\text{O}{}_2{}^{\mathrm{?}}{}_{\mathrm{?}}$ generation by the resolved flavoprotein fraction was not detectable, however it was competent in the transfer of electrons from NADPH to artificial electron acceptors. The resolved cytochrome b₅₅₉, depleted of flavoprotein, demonstrated no measureable NADPH dependent $\text{O}{}_2{}^{\mathrm{?}}{}_{\mathrm{?}}$ generating activity and was not reduced by NADPH under anaerobic conditions. The dithionite reduced form of the resolved cytochrome b₅₅₉ was rapidly oxidized by oxygen, as was the cytochrome b₅₅₉ in the intact oxidase.     

Molecular characterization of the HMW glutenin genes Dt x1.5?+?Dt y10 from Aegilops tauschii and their PCR-mediated recombinants

The high molecular weight (HMW) glutenin subunits, D^tx1.5 + D^ty10, are special types of storage proteins found in Aegilops tauschii that are never found in common wheat (Triticum aestivum). This study reports the characterization of the complete open reading frames (ORFs) of the HMW glutenin genes, D^tx1.5 and D^ty10, using a restrict-enzyme based method named the restricted deletion method (RDM). The D^tx1.5 and D^ty10 were found to have an identical structure compared with the other published HMW glutenin genes. Comparison of the deduced protein sequences also indicated that the D^ty10 in Ae. tauschii differed from its counterpart Dy10 in common wheat, by having insertions and deletions in the central repetitive domain. This result confirms the two subunits with same mobility in SDS-PAGE are different types of HMW glutenin subunits. In addition, four PCR-mediated recombinants of the D^tx1.5 and D^ty10 genes were amplified using a PCR program with shorter extension time. The recombinants had a similar structure to their corresponding natural genes, but a significantly different central repetitive domain. Western blot analysis exhibited a normal expression of the recombinants in E. coli. In addition to its usefulness for studying structure and function of the HMW glutenin subunits, the PCR-mediated recombination may provide an efficient method to generate novel HMW glutenin genes for wheat breeding.     

Solid-state structure of N-o-, N-m-, and N-p-nitrophenyl-2,3,4-tri-O-acetyl-β-d-xylopyranosylamines

Comprehensive structural analyses were performed for N-o-, N-m-, and N-p-nitrophenyl-2,3,4-tri-O-acetyl-β-d-xylopyranosylamines. Single-crystal X-ray diffraction data were collected and revealed that one compound under investigation undergoes temperature-dependent polymorph transitions (crystal structures of three polymorphs were obtained). The number of molecules in the independent part of the crystal unit cells was in agreement with the number of resonances in solid-state ¹³C NMR spectra. Therefore, the compounds exist as single polymorphs at room temperature, as confirmed by powder X-ray diffraction measurements. Significant differences in ¹³C chemical shifts between solution and solid-state NMR for selected carbon atoms confirmed the existence of intra- and/or intermolecular interactions.     

Immunoreactivity of subunits of the (Na+ + K+)-ATPase Cross-reactivity of the α,α+ and β forms in different organs and species

The immunologic cross-reactivity of the α and α+ forms of the large subunit and the β subunit of the ($\text{Na}{}^{\mathrm{+}}\text{+}\text{K}{}^{\mathrm{+}}\text{)-}\text{ATPase}$ from brain and kidney preparations was examined using rabbit antiserum prepared against the purified holo lamb kidney enzyme. As previously reported by Sweadner ((1979) J. Biol. Chem. 254, 6060–6067) phosphorylation of the large subunit of the ($\text{Na}{}^{\mathrm{+}}\text{+}\text{K}{}^{\mathrm{+}}\text{)-}\text{ATPase}$ in the presence of Na⁺, Mg²⁺, and [$\text{γ-}{}^{32}\text{P}\text{]}\text{ATP}$ revealed that dog and, very likely, rat brain contain two forms of the large subunit (designated α and α+) while dog, rat, and lamb kidney contain only one form (α). The cross-reactivity of the α and α+ forms in these preparations was investigated by resolving the subunits by SDS-polyacrylamide gel electrophoresis. The separated polypeptides were transferred to unmodified nitrocellulose paper, and reacted with rabbit anti-lamb kidney serum, followed by detection of the antigen-antibody complex with ¹²⁵I-labeled protein A and autoradiography. By this method, the α and α+ forms of rat and dog brain, as well as the α form found in kidney, were shown to cross-react. In addition, membranes from human cerebral cortex were shown to contain two immunoreactive bands corresponding to the α and α+ forms of dog brain. In contrast, the brain of the insect Manduca sexta contains only one immunoreactive polypeptide with a molecular weight intermediate to the α and α+ forms of dog brain. The β subunit from lamb, dog and rat kidney and from dog and rat brain cross-reacts with anti-lamb kidney ($\text{Na}{}^{\mathrm{+}}\text{+}\text{K}{}^{\mathrm{+}}\text{)-}\text{ATPase}$ serum. The mobility of the β subunit from dog and rat brain on SDS-polyacrylamide electrophoresis gels is greater than the mobility of the β subunit from lamb, rat or dog kidney.     

Trichomonasfetus—Induced abortion

$\text{History}$ and $\text{Clinical}$$\text{Signs}$: Herds infected with $\text{Trichomonas}$$\text{fetus}$ have histories of infertility, occasional abortions, and pyometra.$\text{Gross}$$\text{Lesions}$: There are no specific gross lesions in the fetus. The fetuses are usually aborted in the first half of gestation and may or may not be accompanied by the placenta.$\text{Microscopic}$$\text{Lesions}$: There are no specific microscopic lesions.$\text{Cultural}$$\text{Procedures}$: It is ordinarily not necessary to culture $\text{T.}$$\text{fetus}$ in order to demonstrate its presence in placental fluids and/or abomasal contents.$\text{Serologic}$$\text{Procedures}$: There are no suitable seroligic procedures for diagnosing Trichomoniasis.$\text{Special}$$\text{Procedures}$: Wet mounts of abomasal contents and/or placental fluids are examined microscopically for $\text{T.}$$\text{fetus}$.$\text{Preferred}$$\text{Diagnostic}$$\text{Procedures}$: Demonstrate the presence of $\text{T.}$$\text{fetus}$ by microscopic examination of wet mounts of placental fluids and/or abomasal contents.