Molecular characterisation of segments 1 to 6 of Rice black-streaked dwarf virus from China provides the complete genome

The nucleotide sequences of segments S1 to S6 of a Chinese isolate of Rice black-streaked dwarf virus (RBSDV) were determined. This provides the first complete sequence of a plant pathogenic member of the genus Fijivirus. The complete ten-segment genome has 29,141 nucleotides, making it the largest reovirus genome so far reported. Each of the segments S1-S6 is predicted to encode a single major protein. Protein comparisons indicated that S1 encoded an RNA dependent RNA polymerase, with similarities to that encoded by S1 of Nilaparvata lugens reovirus (NLRV). S2 and S3 appeared to be homologous to S3 and S4 respectively of both Fiji disease virus (FDV) and NLRV. The protein encoded on S4 showed some similarity to that of NLRV S2. The proteins encoded on S5 and S6, though similar in size to those of NLRV S5 and S6, had no detectable homologies to them or to any other known protein.

BNips: a group of pro-apoptotic proteins in the Bcl-2 family

BNip (formerly known as Nip) proteins, including homologues isolated from human, mouse and Caenorhabditis. elegans, are a relatively new subgroup of the Bcl-2 family. These proteins are classified into this family based on limited sequence homology with the Bcl-2 homology domain 3 and carboxyl terminal transmembrane domain. BNip proteins were first discovered based on their interaction with the adenovirus E1B 19 kDa/Bcl-2 family protein and since then, their roles in cell death pathways have been actively studied. However, the precise mechanisms by which the BNip proteins induce apoptosis and/or necrosis remain to be determined. To advance our knowledge, we have provided a summary and review of current literature regarding BNip proteins including comparative sequence analysis, mutational mapping of the functional domains, and cell death mechanisms involving disruption of mitochondrial homeostasis. Since BNip proteins are expressed at high levels in the heart as compared to other organs, their roles in cardiomyocyte injury during hypoxia or viral infection is a focus of this review. Finally, we discuss potential directions for further study on this increasingly important group of pro-apoptotic proteins.

Sonocatalytic degradation of RhB over LuFeO3 particles under ultrasonic irradiation

LuFeO3 particles with an average particle size of ∼200 nm were synthesized via a polyacrylamide gel route. The sonocatalytic activity of LuFeO3 particles was evaluated by the degradation of Rhodamine B (RhB) under ultrasonic irradiation, revealing that they exhibit a good sonocatalytic activity. The effects of various experimental factors including ultrasonic frequency (f), reaction solution temperature (T), catalyst dosage (Ccatalyst), initial RhB concentration (CRhB), and pH value on the sonocatalysis efficiency were investigated. It is found that the former four factors have an important influence on the sonocatalytic degradation of RhB, where the best degradation conditions are obtained to be f=60 kHz, T=40 °C, Ccatalyst=4 g L(-1), and CRhB=5 mg L(-1). The pH value has a relatively small effect on the sonocatalytic degradation of RhB compared with other experimental factors. Hydroxyl (·OH) radicals were detected by fluorimetry using terephthalic acid as a probe molecule, revealing that they are produced over the ultrasonic-irradiated LuFeO3 particles. The addition of ethanol leads to a quenching of ·OH radicals and a simultaneous decrease in the RhB degradation. This indicates that ·OH radicals are the primary active species responsible for the dye degradation.

A study for maternal thyroid hormone deficiency during the first half of pregnancy in China

BACKGROUND

Maternal thyroid hormone deficiency is the most common disorder of thyroid function during pregnancy and can influence the outcome for mother and foetus. The purpose of this study was to investigate the prevalence of thyroid hormone deficiency during the first half of pregnancy in iodine sufficient areas of China.

MATERIALS AND METHODS

Four thousand eight hundred pregnant women from 10 hospitals during the first 20 weeks of gestation were enrolled in this study. All sera obtained from pregnant women were measured for thyrotropin, free thyroxine and thyroid peroxidase antibody. Screening for thyroid hormone deficiency was performed on pregnant women using gestational age-specific reference intervals or non-pregnant population reference intervals.

RESULTS

With gestational age-specific reference intervals as the criterion, the prevalence of subclinical hypothyroidism at 4, 8, 12,16 and 20 weeks of gestation was 4.59%, 6.15%, 4.68%, 4.53% and 5.96%, respectively, and the prevalence of hypothyroxinaemia was 3.69%, 1.11%, 2.92%, 1.29% and 2.29%, respectively. Different prevalence was obtained when non-pregnant population reference intervals was used as the criterion. If non-pregnant population reference intervals were used, the percentage of potentially misclassified cases of subclinical hypothyroidism were 0.18%, 2.85%, 4.1%, 3.24%, and 3.21%, respectively, and 3.45%, 0.66%, 2.34%, 1.29%, and 1.83%, respectively, in potentially misclassified cases of hypothyroxinaemia.

CONCLUSIONS

The percentage of potentially misclassified cases of subclinical hypothyroidism and hypothyroxinaemia in pregnant women decreased by using the gestational age-specific reference intervals as a diagnostic criteria during the first half of pregnancy.

Identification of a heparin-binding protein in bovine seminal fluid as tissue inhibitor of metalloproteinases-2

Presence or absence of three distinct bovine seminal heparin-binding proteins (21-31 kDa) recognized in sperm extracts by a monoclonal antibody, M1, is a diagnostic indicator of fertility differences among bulls producing normal semen. We recently identified a 31 kDa fertility-associated antigenin bovine seminal fluid as a unique DNase I-like protein. We now report purification and identification of a 24 kDa seminal heparin-binding protein (HBP-24) recognized by M1. N-terminal microsequence analysis of HBP-24 purified from seminal fluid yielded 20 amino acid residues that displayed 90% identity to the N-terminus of a bovine metalloproteinase inhibitor identified as tissue inhibitor of metalloproteinases-2 (TIMP-2). A single immunoreactive band migrating at 24 kDa was detected in Western blots of cauda epididymal sperm extracts following incubation with purified seminal heparin-binding proteins and subsequent washing in vitro, indicating TIMP-2 bound to sperm membranes. Expression of TIMP-2 mRNA was detected by RT-PCR in bovine bulbourethral gland, prostate, and seminal vesicles. Mobility of the 24 kDa heparin-binding protein increased under nonreducing SDS-PAGE to approximately 21 kDa, characteristic of the reported molecular mass of TIMP-2. To our knowledge, this is the first report of TIMP-2 binding to spermatozoa and of TIMP-2 mRNA expression in bovine accessory sex glands. These results corroborate previous reports regarding the site of production of heparin-binding proteins that are related to bull fertility, and suggest that TIMP-2 influences fertility of bulls, either through inhibition of metalloprotease activity in semen or via undefined activities independent of matrix metalloproteinase (MMP) inhibition.

A novel action of the proton pump inhibitor rabeprazole and its thioether derivative against the motility of Helicobacter pylori

The motility of Helicobacter pylori was maximum at 37 degrees C and at pH 6. A newly developed proton pump inhibitor, rabeprazole (RPZ), and its thioether derivative (RPZ-TH) markedly inhibited the motility of H. pylori. The concentrations of the drug necessary to inhibit 50% of the motility were 0.25, 16, 16, and >64 microgram/ml for RPZ-TH, RPZ, lansoprazole, and omeprazole, respectively. No such inhibitory effects were observed with H(2) blockers or anti-H. pylori agents. The motilities of Campylobacter jejuni and C. coli-but not those of Vibrio cholerae O1 and O139, Vibrio parahaemolyticus, Salmonella enterica serovar Typhimurium, and Proteus mirabilis-were also inhibited. Prolonged incubation with RPZ or RPZ-TH inhibited bacterial growth of only H. pylori, except for a turbid colony mutant. The results indicate that RPZ and RPZ-TH have a characteristic inhibitory effect against the motility of H. pylori (spiral-shaped bacteria), which is distinguished from that against bacterial growth.

Highly sensitive flexible three-axis tactile sensors based on the interface contact resistance of microstructured graphene

The lack of high-performance tactile sensors, especially for pressure/force, is a huge obstacle for the widespread application of intelligent robots. Current pressure sensors are often operated in the high range of pressure and normal direction, showing a little ability in the low range of pressure and three-axis direction simultaneously. Herein, a highly sensitive flexible tactile sensor with three-axis force sensing capacity is presented by combining microstructured polydimethylsiloxane (PDMS) arrays and a reduced graphene oxide (rGO) film. The deformation of microstructured rGO/PDMS results in a change in the contact area between the rGO film and electrode, leading to a high sensitivity of -1.71 kPa-1 in the low range pressure of 0-225 Pa with a fast response time of 6 ms at a large feature size of 100 μm. To realize three-axis sensing, a sensing unit was built up, which was composed of the adjacent four parts of patterns and electrodes underneath a bump. A mechanical model of the exerted spatial force was established to calculate each axis force component via the deformation of the rGO/PDMS pattern. The experimental results show that the current difference between the adjacent two parts has a strong relationship with the applied force. As a proof of concept, we have demonstrated a 3 × 3 array sensor for arbitrary force sensing. Our tactile sensor would be used in transmitting information from a gentle spatial force and would exhibit broad applications as e-skin in integrated robots.

The direct electrochemistry of myoglobin at a DL-homocysteine self-assembled gold electrode

A pair of well-defined redox waves of myoglobin at a DL-homocysteine self-assembled gold electrode was achieved. Myoglobin can strongly bind to the homocysteine self-assembled gold electrode, so the Mb-Hcy self-assembled gold electrode was prepared and the standard rate constant (ks) of Mb was calculated as 9.3 x 10(-1) s(-1). X-ray photoelectron spectroscopy (XPS) measurements demonstrated that Hcy monolayer was formed and Mb was bound to Hcy monolayer.

Oxidative stress induced necroptosis activation is involved in the pathogenesis of hyperoxic acute lung injury

Necroptosis has been found to be involved in the pathogenesis of some lung diseases, but its role in hyperoxic acute lung injury (HALI) is still unclear. This study aimed to investigate contribution of necroptosis to the pathogenesis of HALI induced by hyperbaric hyperoxia exposure in a rat model. Rats were divided into control group, HALI group, Nec-1 (necroptosis inhibitor) group and edaravone group. Rats were exposed to pure oxygen at 250 kPa for 6 h to induce HALI. At 30 min before hyperoxia exposure, rats were intraperitoneally injected with Nec-1 or edaravone, and sacrificed at 24 h after hyperoxia exposure. Lung injury was evaluated by histology, lung water to dry ratio (W/D) and bronchoalveolar lavage fluid (BALF) biochemistry; the serum and plasma oxidative stress, expression of RIP1, RIP3 and MLKL, and interaction between RIP1 and RIP3 were determined. Results showed hyperoxia exposure significantly caused damage to lung and increased necroptotic cells and the expression of RIP1, RIP3 and MLKL. Edaravone pre-treatment not only inhibited the oxidative stress in HALI, but also reduced necroptotic cells, decreased the expression of RIP1, RIP3 and MLKL and improved lung pathology. Nec-1 pretreatment inhibited necroptosis and improved lung pathology, but had little influence on oxidative stress. This study suggests hyperoxia exposure induces oxidative stress may activate necroptosis, involving in the pathology of HALI, and strategies targeting necroptosis may become promising treatments for HALI.

Artificial insemination outcomes in beef females using bovine sperm with a detectable fertility-associated antigen

In this study, semen samples from 25 bulls that had passed a breeding soundness evaluation were analyzed for the presence or absence of a 31-kDa protein, known as fertility-associated antigen (FAA), on spermatozoal membranes. Eighteen bulls had FAA on sperm (FAA-positive) and seven were devoid of FAA on sperm (FAA-negative). A single ejaculate from each bull was extended and frozen with 25 to 30 x 10(6) sperm in .5-mL straws. Crossbred replacement heifers (n = 865) were estrus-synchronized and artificially inseminated either at timed AI or 12 h after they were detected in estrus. Mature cows (n = 285) were inseminated 12 h after they were detected in estrus during a 45-d AI period. Pregnancy rates (pooled) to first AI service for females (n = 764) inseminated with FAA-positive sperm were 65.6% and were 49.7% for females (n = 386) inseminated with FAA-negative sperm (P < .005). Among the estrus-synchronized replacement heifers, pregnancy rates to synchronized AI service for heifers (n = 550) inseminated with FAA-positive sperm were 62% and were 45.7% for heifers (n = 315) inseminated with FAA-negative sperm (P < .005). These data indicate that pregnancy rates to first AI service at spontaneous and synchronized estrus are higher when using semen from bulls with detectable FAA on spermatozoal membranes compared to semen from bulls devoid of FAA on membranes. Fertility-associated antigen is an important determinant for fertility potential of sperm from bulls to be used in AI breeding programs.

Electrochemical studies of the interaction of adriamycin to DNA

An electrochemical investigation of the interaction of adriamycin (DXH) with DNA on a Hg electrode is reported. In weakly acidic media of pH 4.0-7.0, the addition of DNA to DXH solution results in the decrease of redox peak currents. In the presence of DNA, no new peak appears and the standard rate constant k(s) is not significantly changed. The binding of DXH to DNA by electrostatic attraction and intercalation forms a kind of supramolecular complex DXH-DNA, which is electrochemically non-active. The equilibrium constant for the complex is calculated. The decrease in peak current is proportional to DNA concentration and can be used to determine DNA concentration.

Ultrahigh-energy photons up to 1.4 petaelectronvolts from 12 γ-ray Galactic sources

The extension of the cosmic-ray spectrum beyond 1 petaelectronvolt (PeV; 10¹⁵ electronvolts) indicates the existence of the so-called PeVatrons-cosmic-ray factories that accelerate particles to PeV energies. We need to locate and identify such objects to find the origin of Galactic cosmic rays¹. The principal signature of both electron and proton PeVatrons is ultrahigh-energy (exceeding 100 TeV) γ radiation. Evidence of the presence of a proton PeVatron has been found in the Galactic Centre, according to the detection of a hard-spectrum radiation extending to 0.04 PeV (ref. ²). Although γ-rays with energies slightly higher than 0.1 PeV have been reported from a few objects in the Galactic plane^3-6, unbiased identification and in-depth exploration of PeVatrons requires detection of γ-rays with energies well above 0.1 PeV. Here we report the detection of more than 530 photons at energies above 100 teraelectronvolts and up to 1.4 PeV from 12 ultrahigh-energy γ-ray sources with a statistical significance greater than seven standard deviations. Despite having several potential counterparts in their proximity, including pulsar wind nebulae, supernova remnants and star-forming regions, the PeVatrons responsible for the ultrahigh-energy γ-rays have not yet been firmly localized and identified (except for the Crab Nebula), leaving open the origin of these extreme accelerators.

Association of 1704G/T and G82S polymorphisms in the receptor for advanced glycation end products gene with diabetic retinopathy in Chinese population

BACKGROUND

The receptor for advanced glycation end products (RAGE) plays an important role in the pathogenesis of diabetic complications. The aim of this study is to investigate the association of the 1704 G/T and G82S polymorphisms in the RAGE gene with diabetic retinopathy (DR).

METHODS

The 1704G/T and G82S polymorphisms were genotyped in 340 Type 2 diabetes (T2DM) without DR subjects (DR- group); 166 T2DM with DR subjects (DR+ group), and 182 normal glucose tolerant subjects (NGT group). The genotypes were detected by the methods of ligase detection reaction coupled PCR.

RESULTS

There was no evident difference in the 1704G/T and G82S genotypic and allelic frequencies distribution between NGT and T2DM subjects. However, the frequences of G/A+AA genotypes (60.6%) and A allele (36.4%) of G82S were significantly higher in DR+ group than those (38.4%; 20.9%, respectively) in DR- group (p=0.01and p=0.007, respectively). Furthermore, haplotype analysis revealed that the frequency of G-A haplotype containing 1704G and 82S allele in DR+ group was significantly higher than that in DR- group (33.5% vs 19.6%, p=0.01). The multiple logistic regression analysis indicated that the G82S polymorphism [odds ratio (OR): 2.964, 95% confidence interval (CI): 1.013-5.46, p=0.029] and diabetes duration (OR: 1.013, 95% CI: 1.007-1.02, p<0.001) were independent risk factors for DR.

CONCLUSIONS

G82S polymorphism in the RAGE gene is associated with DR and G-A haplotype containing 1704G and 82S allele might be a genetic marker of DR in Chinese T2DM patients.

Peta-electron volt gamma-ray emission from the Crab Nebula

The Crab Nebula is a bright source of gamma rays powered by the Crab Pulsar's rotational energy through the formation and termination of a relativistic electron-positron wind. We report the detection of gamma rays from this source with energies from 5 × 10^-4 to 1.1 peta-electron volts with a spectrum showing gradual steepening over three energy decades. The ultrahigh-energy photons imply the presence of a peta-electron volt electron accelerator (a pevatron) in the nebula, with an acceleration rate exceeding 15% of the theoretical limit. We constrain the pevatron's size between 0.025 and 0.1 parsecs and the magnetic field to ≈110 microgauss. The production rate of peta-electron volt electrons, 2.5 × 10³⁶ ergs per second, constitutes 0.5% of the pulsar spin-down luminosity, although we cannot exclude a contribution of peta-electron volt protons to the production of the highest-energy gamma rays.

Longissimus dorsi muscle transcriptomic analysis of Yunling and Chinese simmental cattle differing in intramuscular fat content and fatty acid composition

Intramuscular fat (IMF) content and fatty acid (FA) composition vary significantly across beef cattle breeds, which play an important role in taste and nutritional value. However, the molecular mechanisms underlying these phenotypic differences remain unknown. The present study compared meat quality traits between Yunling cattle and Chinese Simmental cattle. Yunling cattle showed a lower IMF content and proportion of monounsaturated fatty acids (MUFA), as well as higher proportions of saturated fatty acids (SFA), polyunsaturated fatty acids (PUFA), and short-chain fatty acids (sc-FA) in the longissimus dorsi (LD) muscle than Chinese Simmental cattle. To further identify the candidate genes and pathways responsible for these phenotypic differences, the transcriptome of LD muscle from the two breeds were measured using RNA-seq. A total of 1347 differentially expressed genes were identified. The major metabolic pathways that were differentially modulated were lipolysis and glycometabolism. Yunling cattle showed a higher expression of lipolysis genes (ALDH9A1, ACSL5, ACADM, ACAT2, ACOT2) and a lower expression of genes related to glycometabolism (PGM1, GALM, PGM1, GPI, LDHA). This research identified candidate genes and pathways for IMF content and FA composition in the LD muscle of beef cattle, which may facilitate the design of new selection strategies to improve meat quality.

Inhibitory action of a novel proton pump inhibitor, rabeprazole, and its thioether derivative against the growth and motility of clarithromycin-resistant Helicobacter pylori

BACKGROUND

Clarithromycin-resistant Helicobacter pylori (CRHP) has increasingly been isolated from patients in Japan. The aim of our study was to test whether proton pump inhibitors (PPIs) and their thioether derivatives, which are secreted into the gastric mucosa, could inhibit the growth and motility (a factor in colonization) of CRHP.

MATERIALS AND METHODS

CRHP was isolated from patients who had experienced gastritis or peptic ulcers in Tokyo and Niigata. Drugs and related agents tested were omeprazole, lansoprazole, rabeprazole, the thioether derivative of rabeprazole (rabeprazole-TH), clarithromycin, amoxicillin and metronidazole. The MICs of the drugs and agents for H. pylori strains were determined by the agar dilution

METHOD

Bacterial swimming in a liquid layer was examined under an inverted, phase-contrast microscope.

RESULTS

The PPIs and rabeprazole-TH, but not the anti-H. pylori agents, inhibited the motility of CRHP at both pH 7.4 and 6.0. The concentrations (microg/ml) necessary to inhibit 50% of the motility at pH 7.4 were 0.25-0.5, 8-32, 8-16 and 128-256 for rabeprazole-TH, rabeprazole, lansoprazole and omeprazole, respectively. Rabeprazole-TH exhibited the strongest inhibitory effect against the growth of CRPH (MIC, 0.5 microg/ml).

CONCLUSION

Rabeprazole-TH, which is secreted into the gastric mucosa, had the strongest inhibitory action against both the growth and motility of CRHP, suggesting that it is a potential novel agent for CRHP eradication.

Retrospective evidence that the MHC (B haplotype) of chickens influences genetic resistance to attenuated infectious bronchitis vaccine strains in chickens

Infectious bronchitis is a respiratory disease of chickens that is caused by the coronavirus infectious bronchitis virus (IBV). Virtually all broiler and layer breeder flocks are routinely vaccinated against IBV. Two hatches of 1-day-old chicks from four lines were mistakenly vaccinated for infectious bronchitis using a moderately attenuated vaccine designed for chicks of an older age. The vaccination resulted in high mortality, and chicks from three of four lines died with signs typical of infectious bronchitis. The mortality that occurred using this less-attenuated vaccine was significantly influenced by the genetic line, and the MHC (B) haplotype in chickens of three B congenic lines. B congenic chickens possessing the B*15 haplotype were resistant in contrast to chickens possessing the B*13 or B*21 haplotypes. Chicks from two further hatches of the four lines were vaccinated appropriately with a more attenuated IBV vaccine, and only limited chick mortality was seen. These retrospective data from two repeated hatches confirm earlier data indicating chicken genes influence resistance to IBV, and indicate for the first time that genes tightly linked to the B haplotype are relevant in resistance to IBV. Due to extenuating circumstances it was not possible to verify results with chicks from F2 matings. Factors that may enhance definition of the role of the B haplotype in immune response to IBV, and the desirability for further analysis of a B haplotype-linked influence on immunity to IBV are discussed.

Physiological responses in thermal stressed Jersey cows subjected to different management strategies

The effects of cooling and recombinant bovine somatotropin (rbST) on milk yield, reproductive performance, and health of Jersey cattle during summer thermal stress were measured for 2 yr. Cows were assigned to one of two groups based upon days in milk (DIM), parity, and genetic index. Year 1 and year 2 control cows (n = 143, n = 183, respectively) were housed in a pen with only shades. Cooled treatment cows each year (n = 142, n = 180) were housed with a spray and fan system for evaporative cooling. Cows were assigned at various days postpartum, not before d 63, coincident with commencement of rbST injections. One half of cows in each group received rbST on d 63 postpartum. Cows were assigned to the shade trial ranging from d 63 to 190. Cooled versus noncooled DIM were similar at the start of the trial. Trials began on July 1, 1999, and July 1, 2000, and concluded on September 30, 1999, and September 25, 2000. The ANOVA of daily milk weight data was conducted utilizing a 2 x 2 factorial design with cooling and rbST treatments as main effects. Cooling in combination with rbST increased milk yield compared with no cooling and no rbST for 1999 and 2000 (25.5 versus 21.8 kg/d, and 23.7 versus 20.5 kg/d, respectively). In general, cooling improved health and reproductive performance.

Identification of dauricine and its metabolites in rat urine by liquid chromatography–tandem mass spectrometry

A rapid, sensitive and specific liquid chromatographic-electrospray ionization (ESI) tandem ion trap mass spectrometric method has been developed for identification of dauricine and its metabolites in rat urine. Six healthy rats were administrated a single dose (100 mg/kg) of dauricine by oral gavage. The urine were sampled from 0 to 24 h and purified by using a C18 solid-phase extraction (SPE) cartridge, then the purified urine samples were separated on a reversed-phase C18 column using methanol/2 mmol/L ammonium acetate (70:30, v/v, adjusted to pH 3.5 with formic acid) as mobile phase and detected by an on-line MS detector. Identification and structural elucidation of the metabolites were performed by comparing their changes in molecular mass (Deltam) and full scan MS(n) spectra with those of the parent drug. At least eight metabolites (such as N-demethyl, dehydrogenate, demethoxyl, hydroxyl, glucuronide conjugated and sulfate conjugated metabolites) and the parent drug were found in rat urine.

Impact of spatial variations in water quality and hydrological factors on the food-web structure in urban aquatic environments

Global aquatic ecosystems are essential to human existence and have deteriorated seriously in recent years. Understanding the influence mechanism of habitat variation on the structure of the food-web allows the effective recovery of the health of degraded ecosystems. Whereas most previous studies focused on the selection of driving habitat factors, the impact of habitat variation on the food-web structure was rarely studied, resulting in the low success rate of ecosystem restoration projects globally. This paper presents a framework for exploring the effects of spatial variations in water quality and hydrological habitat factors on the food-web structure in city waters. Indices for the evaluation of the food-web structure are first determined by integrating model-parameter extraction via literature refinement. The key water quality and hydrological factors are then determined by coupling canonical correspondence analysis with partial least squares regression. Their spatial variation is investigated using spatial autocorrelation. Finally, fuzzy clustering is applied to analyze the influence of the spatial variations in water quality and hydrological factors on the food-web structure. The results obtained in Ji'nan, the pilot city of water ecological civilization in China, show that the Shannon diversity index, connectance index, omnivory index, and the ratio of total primary production to the total respiration are important indicators of food-web structural change. They show that the driving factors affecting the aquatic food-web structure in Ji'nan are hydrological factors (e.g., river width, water depth, and stream flow), physical aspects of water quality (e.g., air temperature, water temperature, electrical conductivity, and transparency), and chemical aspects (e.g., potassium, dissolved oxygen, calcium, and total hardness). They also show that the stability of the food-web is more prone to spatial variations in water quality than in hydrological factors. Higher electrical conductivity, potassium, total hardness, and air temperature lead to deteriorated food-web structures, whereas better transparency improves structure and stability. We found that water and air temperature are the most important factors in the spatial variation of the food-web structure in the study area, followed by total hardness. Transparency is the least important factor. Large disparities and varied spatial distributions exist in the driving effects of water quality and hydrological factors across regions attributable to differences in geographical environments, water salinity (fresh vs. sea water), and environmental factors (e.g., water pollution). The above methods and results serve as a theoretical and scientific basis for a high success rate of aquatic ecosystem restoration projects in the study area and other cities worldwide.

Retroviral delivery of RNA interference against Marek's disease virus in vivo

The process of RNA interference (RNAi) has been exploited in cultured chicken cells and in chick embryos to assess the effect of specific gene inhibition on phenotypes related to development and disease. We previously demonstrated that avian leukosis virus-based retroviral vectors are capable of delivering effective RNAi against Marek's disease virus (MDV) in cell culture. In this study, similar RNAi vectors are shown to reduce the replication of MDV in live chickens. Retroviral vectors were introduced into d 0 chick embryos, followed by incubation until hatching. Chicks were challenged with 500 pfu of strain 648A MDV at day of hatch, followed by assays for viremia at 14 d postinfection. Birds were monitored for signs of Marek's disease for 8 wk. A stem-loop PCR assay was developed to measure siRNA expression levels in birds. Delivery of RNAi co-targeting the MDV gB glycoprotein gene and ICP4 transcriptional regulatory gene significantly reduced MDV viremia in vivo, although to lesser extents than were observed in cell culture. Concomitant reductions in disease incidence also were observed, and the extent of this effect depended on the potency of the MDV challenge virus inoculum. Successful modification of phenotypic traits in live birds with retroviral RNAi vectors opens up the possibility that such approaches could be used to alter the expression of candidate genes hypothesized to influence a variety of quantitative traits including disease susceptibility.

17O NMR and crystalline hydrates

17O NMR is complementary to 2H NMR for studies of hydrate structure and dynamics in solids, insofar as the quadrupole coupling parameters can be accurately determined. At a Larmor frequency of 34.2 MHz, the effects of a large 17O quadrupole coupling (e2qQ/h approximately 7 MHz) on both the orientational dependence of the central transition resonance frequency and its observation by cross-polarization are examined in powders and a single crystal of oxalic acid dihydrate. Comparison with the exact energies shows that the variation of the central transition frequency with tensor orientation is accurately described as a second-order perturbation, even when e2qQ/h and the Larmor frequency are comparable. The combined chemical and quadrupole-induced shifts of the central transition frequency are separated by their distinct transformation properties, and we report the H2(17)O quadrupole coupling tensor in alpha-oxalic acid dihydrate, which is compared with the hydrogen bonding structure. Excitation of the central transition by cross-polarization is examined in terms of the 17O nutation frequency. Distortions in powder patterns and the loss of lines in single-crystal spectra owing to the orientational dependence of the first-order quadrupole coupling are verified, and simple methods for mitigating the problem in single-crystal and powder experiments are presented.

Lymphoid Organ Size Varies Among Inbred Lines 63 and 72 and Their Thirteen Recombinant Congenic Strains of Chickens with the Same Major Histocompatibility Complex

The objective was to evaluate lymphoid organ size in chickens from a series of 13 recombinant congenic strains (RCS) and their highly inbred parental lines (6(3) and 7(2)). The parental line 6(3) was selected for resistance to tumors induced by Marek's disease virus and avian leukosis viruses, whereas line 7(2) was selected for susceptibility to these tumors. Each RCS on the average contains a random one-eighth of genome from the donor line 7(2). Previous studies have shown that lines 6(3) and 7(2) differ in the size of primary lymphoid organs; i.e., the bursa of Fabricius (BF) and the lobes of the thymus (T) are smaller in line 6(3) than line 7(2). In the current study, the relative size of the T, BF, and spleen was first examined in about 15 males from each of 13 RCS and the 2 parental lines at 60 to 69 d of age. The differences of relative BF, T, and spleen size among the RCS and the parental lines 6(3) and 7(2) differed significantly (P < 0.001). Males and females from 4 RCS and the 2 parental lines were evaluated a second time, and differences in the relative sizes in lymphoid organs among the RCS and parental lines were consistent. In 2 RCS, the size of the T and BF was comparatively large as in line 7(2), leading to the conclusion that different allelic forms at 1 or more loci in these RCS regulate the size of both organs. In 2 other RCS, the BF was large compared with the T, suggesting that allelic forms at some loci in these RCS influence the BF independent of the T. The relative lymphoid organ size among the RCS appeared to cosegregate with the concentration of IgG in the plasma measured previously. The evaluation of genomic variability of these lines is underway, and the RCS are available for research on traits that differ between lines 6(3) and 7(2).