Interspecific hybridization and caste specificity of protein in fire ant     

Hung AC  Vinson SB 《Science (New York, N.Y.)》1977,196(4297):1458-1460

One natural population of fire ant in Texas was found to be a hybrid between Solenopsis geminata and S. xyloni. Evidence from isozyme studies and breeding experiments is provided to demonstrate interspecific hybridization in ants. In this hybrid population, all worker ants have both parental types of nicotinamide adenine dinucleotide-malate dehydrogenase isozymes, but 95 percent of queens possess only the maternal type.  相似文献   

Direct observation of nodes and twofold symmetry in FeSe superconductor     

Song CL  Wang YL  Cheng P  Jiang YP  Li W  Zhang T  Li Z  He K  Wang L  Jia JF  Hung HH  Wu C  Ma X  Chen X  Xue QK 《Science (New York, N.Y.)》2011,332(6036):1410-1413

We investigated the electron-pairing mechanism in an iron-based superconductor, iron selenide (FeSe), using scanning tunneling microscopy and spectroscopy. Tunneling conductance spectra of stoichiometric FeSe crystalline films in their superconducting state revealed evidence for a gap function with nodal lines. Electron pairing with twofold symmetry was demonstrated by direct imaging of quasiparticle excitations in the vicinity of magnetic vortex cores, Fe adatoms, and Se vacancies. The twofold pairing symmetry was further supported by the observation of striped electronic nanostructures in the slightly Se-doped samples. The anisotropy can be explained in terms of the orbital-dependent reconstruction of electronic structure in FeSe.  相似文献   

Direct redox regulation of F-actin assembly and disassembly by Mical   总被引：1，自引：0，他引：1  

Hung RJ  Pak CW  Terman JR 《Science (New York, N.Y.)》2011,334(6063):1710-1713

Different types of cell behavior, including growth, motility, and navigation, require actin proteins to assemble into filaments. Here, we describe a biochemical process that was able to disassemble actin filaments and limit their reassembly. Actin was a specific substrate of the multidomain oxidation-reduction enzyme, Mical, a poorly understood actin disassembly factor that directly responds to Semaphorin/Plexin extracellular repulsive cues. Actin filament subunits were directly modified by Mical on their conserved pointed-end, which is critical for filament assembly. Mical posttranslationally oxidized the methionine 44 residue within the D-loop of actin, simultaneously severing filaments and decreasing polymerization. This mechanism underlying actin cytoskeletal collapse may have broad physiological and pathological ramifications.  相似文献   

Dietary nano chromium picolinate can ameliorate some of the impacts of heat stress in cross-bred sheep     

Alex T. Hung  Brian J. Leury  Matthew A. Sabin  Fahri Fahri  Kristy DiGiacomo  Tu-Fa Lien  Frank R. Dunshea 《动物营养（英文）》2021,7(1):198

Two studies were conducted to evaluate the effect of nano chromium picolinate (nCrPic) during heat stress (HS) in sheep. In the initial study, 36 Merino × Poll cross-bred sheep were individually penned and allocated to 3 dietary treatments (0, 400 and 800 μg/kg nCrPic) for 8 wk. Body composition was determined at the beginning and end of the experiment using dual energy X-ray absorptiometry. The sheep remained in their dietary groups but were then placed in metabolic cages and randomly allocated within the dietary group to differing ambient temperature regimes, i.e., thermo-neutral (TN) (n = 18) and HS (n = 18), for 3 wk. Dietary nCrPic had no effect on growth performance and body composition during the initial study conducted under TN conditions. Heat stress decreased average daily feed intake (ADFI) (P = 0.002) whereas sheep under HS had reduced average daily gain (ADG) and indeed lost weight (P < 0.001). Dietary nCrPic increased both ADFI (P = 0.041) and ADG (P = 0.049) under both TH and HS conditions such that the performance of sheep receiving supplemental nCrPic and exposed to HS was similar to that of control sheep maintained under TN conditions. Heat stress increased rectal temperature (P < 0.001) and respiration rate (P < 0.001), particularly during the hottest parts of the day as indicated by interactions (P < 0.001) between time of day and thermal treatment. Rectal temperature was lower in sheep fed nCrPic (P = 0.050), particularly under peak HS conditions during the afternoon as indicated by the interactions between dietary nCrPic and time of day (P < 0.001) and dietary nCrPic, thermal treatment and time of day (P = 0.010). Similarly, respiration rate was lower in sheep fed nCrPic under peak HS conditions during the afternoon as indicated by the interactions between dietary nCrPic and thermal treatment (P < 0.001) and dietary nCrPic and time of day (P = 0.030). In conclusion, dietary nCrPic can partially ameliorate the negative effects of HS as indicated by the maintenance of ADFI and decreased physiological responses, such as elevations in rectal temperature and respiration rate.  相似文献   

Isolation and characterization of endophytic bacteria from wild and cultivated soybean varieties     

Pham Q. Hung  Senthil M. Kumar  V. Govindsamy  K. Annapurna 《Biology and Fertility of Soils》2007,44(1):155-162

Endophytic bacteria were isolated from surface sterilized stems, root, and nodules of wild and cultivated soybean varieties. Various phenotypic traits that are expected to be involved in the persistence and functions of the bacteria were analyzed. Most of the isolates from soybean were motile and indoleacetic acid producers, and 70 and 33% of isolates excreted cellulase and pectinase, respectively. These traits may be involved in endophytic characteristics in soybean. Some isolates were resistant to Str₁₀₀, formed capsules, and produced fluorescent pigments. Molecular characterization of selected 35 endophytic bacteria by 16S rDNA–polymerase chain reaction–restriction fragment length polymorphism showed two main clusters at 48 and 43% similarity coefficients in which most of the endophytes belonged. The genetic variation was more among endophytes isolated from Glycine max tissues than from G. soja.  相似文献   

Engulfed pathogen-induced apoptosis in haemocytes of giant freshwater prawn, Macrobrachium rosenbergii     

Hsu JP  Huang C  Liao CM  Hsuan SL  Hung HH  Chien MS 《Journal of fish diseases》2005,28(12):729-735

Haemocytes of the giant freshwater prawn, Macrobrachium rosenbergii, were investigated for the induction of apoptosis after phagocytosis of pathogenic yeasts, bacteria and non-pathogenic latex beads in vitro. Isolated haemocytes of M. rosenbergii were cultured at a ratio of 1:50 haemocytes to pathogen with the yeast Debaryomyces hansenii, the bacteria Aeromonas hydrophila or Enterococcus faecium, or with latex beads at 25 degrees C for 2 h, followed by washing to remove free particles. At least 200 haemocytes were counted to determine the phagocytosis rate, and the results showed that haemocytes engulfed latex beads at a higher rate than the aquatic pathogens. By transmission electron microscopy, the yeast- or bacterium-engulfing haemocytes displayed morphological changes characteristic of apoptosis, including formation of cytoplasmic vacuoles, chromatin condensation and fragmentation of nuclei. This pathogen-induced apoptosis was further confirmed by DNA laddering and TUNEL (terminal deoxynucleotidyl transferase-mediated deoxy-UTP nick-end-labelling) assays. Neither haemocytes treated with latex beads nor uninfected haemocytes (control group) showed signs of apoptosis after 48 h in culture.  相似文献   

High-energy diets for white sturgeon, Acipenser transmontanus Richardson   总被引：1，自引：0，他引：1  

S. S. O. Hung  T. Storebakken  Y. Cui  L. Tian  & O. Einen 《Aquaculture Nutrition》1997,3(4):281-286

Four diets formulated for salmon were fed to 0.11 kg white sturgeon, Acipenser transmontanus Richardson, for 8 weeks. Dietary compositions ranged from 258 to 402 g lipid kg⁻¹, 535–378 g protein kg⁻¹ and 22.7–14.4 g protein MJ⁻¹ gross energy.
Fish in all treatments grew rapidly, utilized the diets efficiently and had body compositions similar to what has been found in previous studies, but there were some dietary effects. Sturgeon fed the diet with the highest lipid content and lowest protein/energy ratio had lower ( P < 0.05) specific growth rate, feed efficiency, and liver moisture and protein contents, and 6-phosphogluconate dehydrogenase activity, but higher liver lipid contents than fish fed the other three diets. Condition factor, organ to body weight ratios, whole-body and plasma concentrations of protein, glucose and triglyceride, and liver glucose-6-phosphate dehydrogenase, isocitrate dehydrogenase and malic enzyme activities did not differ significantly among dietary treatments. This suggests that white sturgeon subyearlings can utilize diets with high lipid contents (258–357 g kg⁻¹) to display good growth without major adverse effects on body composition and liver lipogenic enzyme activities.  相似文献   

Effects of feeding a high level of D-glucose on liver function in juvenile white sturgeon (Acipenser transmontanus)     

Kofi Fynn-Aikins  Silas S. O. Hung  Steven G. Hughes 《Fish physiology and biochemistry》1993,12(4):317-325

Juvenile white sturgeon (Acipenser transmontanus) were fed three isonitrogenous and isoenergetic diets containing either 35% D-glucose (HC), a mixture of 20% dextrin and 10% cellulose (MC), or 23% cellulose (LC), to investigate the effects of dietary carbohydrate on liver function. After 8-week feeding, body weight gain of fish fed the HC diet was consistently higher than that of fish fed the MC and LC diets, but was not significantly different from the MC-fed fish. Fish fed the HC diet had significantly (p < 0.05) higher feed efficiencies and liver glycogen concentrations than fish fed the MC and LC diets. Sturgeon were injected intravenously with 10 mg kg^-1 body weight of sulfobromophthalein (BSP) and post-injection blood taken from the caudal vein at 15, 30, 60, and 120 min. No significant differences in plasma BSP concentrations were found among the treatments at these times. Plasma hemoglobin and activities of aspartate and alanine aminotransferase were not affected by the diets. This study suggests that the HC diet does not adversely affect liver function or weight gain. Inclusion of high dietary levels of digestible and inexpensive carbohydrates in commercial sturgeon feeds seems promising, but long-term feeding trials should be conducted to confirm this assertion.  相似文献   

辐照后转移时间对水稻体细胞愈伤组织分化的影响     

斯华敏  Vu Minh Hung  付亚萍  陈秋方  李西明  孙宗修 《核农学报》2001,15(3):134-140

用137Csγ射线辐照 3份籼稻 (OryzasativaL .subsp .Indica)幼穗诱导的愈伤组织 ,研究了辐照剂量、辐照后转移时间对愈伤组织褐化率与分化率的影响。结果发现除了基因型和辐照剂量有明显作用之外 ,辐照后转移时间也有重要作用。辐照后延迟转移时间会不同程度提高褐化率 ,而存活的愈伤组织的分化率却有一定的提高。辐照后 48h转移愈伤组织的效果优于辐照后 2 4h转移愈伤组织的效果。讨论了扩大γ射线辐照愈伤组织的应用范围的可能性  相似文献   

水稻孕穗期和开花期的旱害及其和体内水分分配的关系     

余叔文  刘存德  宋廷生  洪继仁 《作物学报》1963,2(1):95-102

本文比较了两个水稻品种在孕穗期和开花期的旱害,并联系株内的水分状况的改变来说明品种差异的原因。从本试验结果可看出体内水分的重新分配是植株对干旱的适应反应之一,器官生长发育速度的调节是抗旱的一个有效方式。  相似文献