Purification and characterization of an antimicrobial peptide, insect defensin, from immunized house fly (Diptera: Muscidae)

The house fly, Musca domestica L. (Diptera: Muscidae), is involved in phoretic movement of pathogenic agents, but it has a very efficient defense mechanism against infection. It is believed that antimicrobial peptides play a significant role in the defense system of the house fly. Here, we isolated a peptide from the immunized house fly pupae, measured its molecular mass (3987.6 Da) by matrix-assisted laser desorption ionization/time of flight-mass spectrometry, and determined its amino acid sequence by using the Procise Protein Sequencing System (Applied Biosystems, Foster City, CA). The peptide was confirmed as a member of the insect defensin family. It displayed high activity against gram-positive bacteria but lower activity against gram-negative bacteria and fungi. Reverse transcription-polymerase chain reaction showed that the house fly defensin gene was constitutively expressed in naive pupae and strongly up-regulated after immunization. House fly defensin is an amphiphilic peptide with a structure similar to that of the CSalphabeta scaffold of insect defensin A from the flesh fly, Phormia terraenovae Robineau-Desvoidy. To our knowledge, this is the first isolated and characterized house fly antimicrobial peptide, and our work may provide useful information for developing pharmacologically active antimicrobial agents.

Quantitative trait loci mapping of leaf angle and leaf orientation value in maize (Zea mays L.)

A major limiting factor for high productivity of maize (Zea mays L.) in dense planting is light penetration through the canopy. Plant architecture with a narrower leaf angle (LA) and an optimum leaf orientation value (LOV) is desirable to increase light capture for photosynthesis and production per unit area. However, the genetic control of the plant architecture traits remains poorly understood in maize. In this study, QTL for LA, LOV, and related traits were mapped using a set of 229 F(2:3) families derived from the cross between compact and expanded inbred lines, evaluated in three environments. Twenty-five QTL were detected in total. Three of the QTL explained 37.4% and five of the QTL explained 53.9% of the phenotypic variance for LA and LOV, respectively. Two key genome regions controlling leaf angle and leaf orientation were identified. qLA1 and qLOV1 at nearest marker umc2226 on chromosome 1.02 accounted for 20.4 and 23.2% of the phenotypic variance, respectively; qLA5 and qLOV5 at nearest bnlg1287 on chromosome 5 accounted for 9.7 and 9.8% of the phenotypic variance, respectively. These QTL could provide useful information for marker-assisted selection in improving performance of plant architecture with regard to leaf angle and orientation.

Methionine and selenium yeast supplementation of the maternal diets affects antioxidant activity of breeding eggs

Four hundred fifty 52-wk-old Langshan layer hens (dual-purpose type, an indigenous poultry breed of China) were randomly divided into 9 treatments with 5 replicates in each treatment. Birds were fed corn-soybean diets (0.13 mg of Se/kg) supplemented with 0, 0.30, and 0.60 mg/kg of Se from Se yeast and 3.2, 4.0, and 5.4 g of dl-Met/kg, respectively. Increasing Se yeast supplementation significantly increased Se concentration in the egg yolk (P < 0.01) and the Se concentration of the 3.2 g of Met/kg treatment was higher than those of the 4.0 and 5.4 g of Met/kg treatments. Adding 0.3 mg of Se/kg to the diet significantly increased glutathione peroxidase (GSH-Px) activity in the egg yolk compared with 0 and 0.6 mg of Se/kg (P < 0.01) and increasing Se yeast supplementation significantly increased the GSH-Px activity in the egg albumen (P < 0.01). Increasing Met supplementation significantly decreased the GSH-Px activity in both the yolk and the albumen of the eggs (P < 0.01). Methionine supplemented at 3.2 and 4.0 g/kg significantly increased glutathione concentration in the egg yolk compared with 5.4 g of Met/kg (P < 0.01) and increasing Met supplementation increased the glutathione concentration in the egg albumen. Increasing Met supplementation significantly decreased malondialdehyde concentration in the egg yolk (P < 0.01) and Se supplemented at 0 and 0.6 mg/kg increased the malondialdehyde concentrations in the egg yolk compared with 0.3 mg of Se/kg (P < 0.01). Methionine supplemented at 4.0 and 5.4 g/kg significantly decreased carbonyl concentration compared with 3.2 g of Met/kg. The conclusion was drawn that Se yeast and Met supplementation of the maternal diets could enhance antioxidant activity of breeding eggs.

Effects of disulfide bridges glycoprotein E1 on fusogenic activity of Rubella virus

Rubella virus (RUBV) infects cells via an acid-triggered membrane fusion process. RUBV virions contain two cysteine-rich glycoproteins, E2 and E1. The latter is believed to be involved in the membrane fusion. Using a recombinant plasmid containing RUBV E1 and E2, 11 of total 20 cysteines present in the ectodomain of wild type E1 were mutated to test their role in the fusion via the formation of disulfide bridges. The recombinant plasmids containing mutated E1 (Cys2-Cys20) or wild type (wt) E1 were expressed in BHK-21 cells. Their fusogenic and hemadsorption activities in addition to a potential of cell surface expression of E1 and E2 were assayed. The results showed that the fusogenic activity was lost in all tested mutants, while the hemadsorption activity and cell surface expression potential were affected differently in individual mutants. Since only the Cys5 and Cys8 mutations led to a reduction of both hemadsorption and cell surface expression, we assume that these mutations prevented the formation of the disulfide bridge, what led to a misfolding of E1 and consequently to a failure of recognition of E1 by E2. In conclusion, the disulfide bridges disrupted in all the tested mutants appear essential for the cell fusion, while only the disulfide bridge C(5)-C(8) seems to be crucial for the transport of E1 and E2 in the cell.

Novel method for correction of x-ray fluoroscopic image

X-ray fluoroscopic images have been widely used in orthopedic surgery. Unfortunately, the inherent distortion deteriorates the quality of fluoroscopic image. To avoid the discontinuities of local correction techniques and achieve good accuracy in present global correction method, a novel approach for distortion correction is proposed which allows good image quality in relatively acceptable time by combining both global and local methods, and a new local interpolation method is also proposed. Computer simulation and experimental test on fluoroscopic image have been carried out.

Simultaneous assessment of the intraluminal pressure and transit time of the colon using a telemetry technique

Colonic motility disorders are common conditions. However, our understanding of normal and pathological motor functions of the colon remains limited, mainly due to the technical difficulties in accessing this organ for study. To investigate colonic motility under normal physiological conditions, we have developed a novel monitoring system based on a telemetry technique. The system is capable of prolonged and noninvasive measurement of intraluminal pressure changes and transit time of intra-colonic contents. To test the in vivo performance of the monitoring system, 15 healthy volunteers and 15 patients with functional constipation (FC) participated in this study. A single-use telemetry capsule embedded with sensors was ingested by the subjects. The capsule is capable of transmitting colonic pressure and temperature wirelessly. The time of the telemetry capsule entering the segmental colon was detected by ultrasonic detection of the batteries in capsule. Pressure recordings confirmed in general a circadian behavior of colonic motility, as well as its response to waking and meals. In the FC patients, the contractile response to morning awakening and meal ingestion was significantly lower compared to the controls. The transit time measured using this method agreed with the time calculated from radiopaque markers (r = 0.89, p < 0.05). The clinical study proved both the reliability and the noninvasiveness of the system. This capsule-style manometric system may represent a useful tool for the study of physiology and pathology of colonic motor disorders.

[Expression of regulation protein of glial fibrillary acidic protein gene in hippocampus of epileptic rats induced by kainic acid]

AIM AND METHODS

The DNA binding protein from hippocampus of epileptic rats was investigated by southwestern blot, which regulated the expression of glial fibrillary acidic protein (GFAP) gene. Its expression pattern was also studied.

RESULTS

Southwestern blot showed that there were two specific DNA binding proteins that regulated the expression of GFAP gene, and their molecular weight were 39 kDa and 35.5 kDa, respectively. The expression of the DNA binding proteins was markedly increased in hippocampus of kainic acid (KA) + NS group at 5 d, reached the peak at 3 w, lasted for 3 m observed.

CONCLUSION

The results above suggest that KA may increase the expression of GFAP in hippocampus by upregulating the transcription factor that regulated the expression of GFAP gene, which may participate in the formation of epileptic seizures.

[Protective effect of hepatocyte growth factor on hepatocyte poisoning by carbon tetrachloride and related gene expression in rats]

Hepatocyte growth factor (HGF), as a pleiotropic factor, plays important roles in organ regeneration, organogenesis and morphogenesis, but few reports on protective effect of HGF on injured liver are available. The aim of this work was to investigate protective effects of recombinant human HGF (rhHGF) on intoxicated hepatocytes induced by carbon tetrachloride (CCl4). The results are as follows: (1) rhHGF (5 ng/ml) could significantly increase the viability of hepatocytes intoxicated by CCl4 (15 mmol/L), decrease the leakage of intracellular alanine transaminase (ALT) and potassium ions into the culture medium; (2) the combination of rhHGF (5 ng/ml) and epidermal growth factor (EGF) (50 ng/ml) could increase the viability further, decrease the leakage of intracellular ALT and potassium ions of hepatocytes; (3) high expression of HGF and its receptor/c-met gene in regenerating liver after partial hepatectomy and CCl4 (50%, 2.5 ml/kg bw) poisoning were examined respectively by reverse transcription-polymerase chain reaction in rats. The results showed that rhHGF could protect hepatocytes against CCl4 through preventing intracellular ALT and potassium ion leakage, thus suggesting a synergistic effect of rhHGF and EGF on cytoprotection, and high expression of HGF and its receptor/c-met mRNA in the liver treated with PH and CCl4 poisoning. The present study suggests that the expression of HGF and its receptor gene plays an important role in liver regeneration and repair.

[Effect of scorpion venom on the release of GABA in hippocampus of epileptic rats induced by kainic acid]

In the present study, the effect of scorpion venom (SV) on epileptic susceptibility and its neurochemical mechanisms were investigated. After SV or normal saline (NS) administration for three weeks in epileptic rats, epileptic seizures were much more decreased in kainic acid (KA) + SV group than those of KA + NS group. GABA immunocytochemistry showed that both (gamma-aminobutyric acid immunoreactivity (GABA-IR) density and the number of GABA positive neurons were markedly decreased in the ventral hippocampus, especially in hilus of KA + NS group as compared with NS + NS group. However, in the group treated with SV for three weeks, the number of GABA positive neurons and the density of GABA-IR were greater increased than those of both KA + NS group and the NS + NS group. The number of GABA positive neurons and the density of GABA-IR were unchanged in the dorsal hippocampus of all the four groups. The above results suggest that SV may selectively prevent loss of GABAergic interneurons in the ventral hippocampus of rats susceptible to epileptic seizures and increase the release of GABA as an antiepileptic mechanism.

The changes of AP-1 DNA binding activity and components in hippocampus of seizure-sensitive rat induced by kainate

Seizure-sensitive Fisher 344 rats were prepared 7 d after seizure episodes induced by a single subcutaneous administration of convulsive dose (7.5 mg/kg) of kainic acid. The activator protein-1 (AP-1) DNA binding activity and its components in the hippocampus of such rats were examined by Gel shift, Super-shift and Western blot assay. Gel shift assay showed that the basal level of AP-1 DNA binding activity was significantly higher than that of control rat hippocampus. Super-shift showed that only Fra and Jun D antibodies could super-shift AP-1 complex to a higher position. It suggested that the AP-1 complex was composed of Fra and Jun D in hippocampus of the seizure-sensitive rats. Western blot analysis further confirmed that Jun D proteins contained components of 43, 39 and 28 kDa. When secondary seizure stimulations were given to seizure-sensitive rats, the AP-1 DNA binding activity was attenuated and the components of AP-1 proteins changed transiently. In light of our results and those of literature, it appears that all the mentioned changes may play an important role in induction of long-lasting enhancement in seizure susceptibility.

Photon tunneling in a uniaxial crystal film

A method for studying photon tunneling in uniaxial crystal films is presented. The complex refractive index and the complex angle of refraction of the evanescent wave in a crystal are calculated for the most general case. The reflectance and transmittance resulting from the tunneling effect in crystal films are discussed, and the relations among these coefficients and the optical parameters of crystal are found. These relations provide a theoretical basis for characterizing crystal films by means of photon tunneling.

Kainic acid-induced sprouting of dynorphin- and enkephalin-containing mossy fibers in the dentate gyrus of the rat hippocampus

This study utilized Timm histochemistry and immunocytochemistry to determine the prolonged effects of kainic acid on the distribution of dynorphin- and enkephalin-containing mossy fibers in the rat dentate gyrus at progressive time points following kainic acid injection. Beginning 1-2 weeks after kainic acid administration, a progressive increase in the distribution and intensity of staining for supragranular zinc, dynorphin and enkephalin was observed in the dentate gyrus. The kainic acid-induced sprouting of mossy fibers containing dynorphin and enkephalin strongly resembles the pattern observed in the dentate gyrus of humans with temporal lobe epilepsy.

[The effects of single administration of kainic acid on cellular signal transmission pathway and susceptibility to seizure]

In this study, Sprague-Dawley (S.D.) rats were pretreated with kainic acid (KA, 10 mg/kg, i. sc.) 72 days before either deep prepyriform cortex (DPC) kindling or injection of the same dose of KA. The results showed that such pretreatment accelerated the process of kindling, and the KA-induced seizures appeared more severe in behaviours. c-Fos-immunoreactivity (c-Fos-ir) was used to demonstrate the neuronal activity in central nervous system during the provocative dose of KA-induced seizure, as comparing with the control which received normal saline of KA 72 days ago. The results indicated that, the transmission pathways in two groups were just the same; but the time courses of c-fos and c-jun expression in KA pretreated group were accelerated asynchronously; and the synthesis of the proenkephalin mRNA in the Ent was apparently up-regulated. It is suggested that, the long-lasting increase in susceptibility to seizure induced by a single administration of KA may be related to the acceleration of the expression of c-fos/jun and the early onset of the expression of proenkephalin mRNA.

[Chronic toxic effects of aluminum on nervous system in rabbits]

Twenty-one male rabbits were administered with alum (aluminum potassium sulfate) for 32 weeks to study the accumulative toxic effects of aluminum in food additives on central nervous system. Results showed aluminum levels in blood and brain tissue of the animals increased significantly with intake of alum (P < 0.01). Blood zinc levels, and activities of superoxide dismutase (SOD) and monoamine oxidase B (MAO-B) correlated negatively with aluminum levels in blood and brain, and SOD activity correlated negatively to accumulative aluminum deposit and positively to lipid oxide level in brain. Pathological examinations showed lesions in gyrus centralis anterior, gyrus hippocampi and spinal cord of the animals got more severely and extensively with aluminum intake and brain aluminum content, with disarrangement of neurofilaments and neurotubule, and deformation of synaptic structures.

Preliminary study on aluminum content of foods and aluminum intake of residents in Tianjin

Aluminum contents of 64 kinds mof foods in Tianjin were determined. The results showed that the aluminum levels in different kinds of foods varied greatly, and most foodstuffs from natural sources (including contamination from food processing) contained less than 10 mg/kg. Aluminum contents were higher in foodstuffs of plant origin, especially dry beans containing large amounts of aluminum naturally. Lower concentration of aluminum seemed to be present in foodstuffs of animal origin. It was estimated that the potential daily intake of aluminum per person from natural dietary sources in Tianjin was about 3.79 mg. This estimated figure of dietary aluminum intake was very close to the measured data from 24 daily diets of college students, which was 4.86 +/- 1.72 mg. Considering all the potential sources of natural aluminum in foods, water and the individual habitual food, it would appear that most residents in Tianjin would consume 3-10 mg aluminum daily from natural dietary sources.

Design and application of a bifocus lens

A method of designing a bifocus lens is presented. The authors explain how to use the ray-tracing formulas that were suggested in a previous paper [Appl. Opt. 31, 7328 (1992)]. The method of calculating physical quantities in formulas and sign rules is also presented. This method can also be applied to the design of other crystal elements. One useful application of a bifocus lens is as a bifocus interference surface profilometer.

General ray-tracing formulas for crystal

I develop a new method of ray tracing that can be used to analyze the refraction or reflection of rays by both uniaxial and biaxial crystals.

Apomorphine induction of AP-1 DNA binding in the rat striatum after dopamine depletion

The expression of AP-1 transcription factors was assessed in the dopamine-depleted rat striatum over a 1 week period of repeated apomorphine injections. A single injection of apomorphine increased the expression of a 35 kDa Fos-related antigen and Jun proteins and their expression continued to increase until day 3 of repeated apomorphine treatment in dopamine-depleted striata. Apomorphine induces AP-1 transcription factors which may be involved in modulating gene expression in the striatum.

A 35 kDa Fos-related antigen is co-localized with substance P and dynorphin in striatal neurons

The rat striatum after dopamine denervation followed by repeated apomorphine treatment was examined for the co-expression of c-fos and Fos-related antigens with dynorphin, substance P and [Met5]enkephalin using Western blot and immunohistochemical techniques. Administration of apomorphine, a dopamine agonist, elevated the level of 35 kDa Fos-related antigen which co-localized with dynorphin and substance P, but not enkephalin, in striatal neurons.

Decreased glutamate release correlates with elevated dynorphin content in the hippocampus of aged rats with spatial learning deficits

The effects of aging on extracellular glutamate and tissue dynorphin content in the hippocampus were examined in Fischer-344 rats. Young adult (4-month-old) and aged (24-month-old) rats were trained to find a hidden platform in the Morris water task. Aged rats were unable to acquire the spatial learning task as rapidly as young controls. Following behavioral testing, an in vivo microdialysis perfusion method was used to determine extracellular glutamate levels in the hippocampus. There was a 25-35% reduction in extracellular glutamate concentration in both dorsal and ventral hippocampus of aged rats compared to young rats, in the absence of any change in tissue glutamate levels. Radioimmunoassay showed an increase in dynorphin A(1-8)-like immunoreactivity [DYN-A(1-8)LI] in both dorsal and ventral hippocampus, but not striatum, of aged rats. Immunocytochemistry indicated that this increase was localized to the dentate granule cells and mossy fibers. Furthermore, among the aged rats the increase in DYN-A(1-8)LI was inversely correlated with the decrease in extracellular glutamate. These results suggest that the disregulation of dynorphin observed in cognitively impaired aged rats is related to reduced excitatory transmission within the hippocampal formation.