高产水稻土结构特性的初步研究

随着稻、麦的持续高产,高产稳产水稻土的土壤条件日益受到重视,不少单位进行了专门研究(上海市农业科学院土肥植保研究所土壤组,1975;广东省农业科学院土肥所土壤组,1976;中国科学院南京土壤研究所苏南调查组,1977).但研究的内容多偏重于土壤的农业化学性状或土壤形态的描述,而较少进行土壤结构性的研究.     

New dammarane-type saponins from the galls of Sapindus mukorossi

Five new dammarane-type saponins, 3beta,7beta,20(S),22-tetrahydroxydammar-24-ene-3-O-alpha-l-rhamnopyranosyl-(1-->2)-beta-D-glucopyranoside, 3beta,7beta,20(S),22,23-pentahydroxydammar-24-ene-3-O-alpha-l-rhamnopyranosyl-(1-->2)-beta-D-glucopyranoside, 3beta,7beta,20(S),22,25-pentahydroxydammar-23-ene-3-O-alpha-l-rhamnopyranosyl-(1-->2)-beta-D-glucopyranoside, 25-methoxy-3beta,7beta,20(S),22-tetrahydroxydammar-23-ene-3-O-alpha-l-rhamnopyranosyl-(1-->2)-beta-D-glucopyranoside, and 25-methoxy-3beta,7beta,20(R)-trihydroxydammar-23-ene-3-O-alpha-l-rhamnopyranosyl-(1-->2)-beta-D-glucopyranoside, named sapinmusaponins A (1), B (2), C (3), D (4), and E (5), respectively, together with three known phenylpropanoid glycosides (6-8), were isolated from the galls of Sapindus mukorossi. The structures of these saponins were elucidated on the basis of spectroscopic analyses and chemical methods. Preliminary bioassay data revealed that saponins 1 and 3-5 showed moderate cytotoxic activity (ED50 approximately 9-18 microg/mL) against human tumor cell lines (Hepa59T/VGH, NCI, HeLa, and Med) and that 1-5 were inactive in vitro against HIV replication in H9 lymphocytes.     

Inhibitory effect of caffeic acid phenethyl ester on angiogenesis, tumor invasion, and metastasis

Caffeic acid phenethyl ester (CAPE) derived from honeybee propolis has been used as a folk medicine and has several proven biological activities. The present study investigated the effect of CAPE on angiogenesis, tumor invasion, and metastasis. A cytotoxicity assay of CAPE in CT26 colon adenocarcinoma cells showed a dose-dependent decrease in cell viability but no significant influence on the growth of human umbilical vein epithelial cells (HUVEC). A low concentration of CAPE (1.5 microg/mL) inhibited 52.7% of capillary-like tube formation in HUVEC culture on Matrigel. CAPE (6 microg/mL)-treated CT26 cells showed not only inhibited cell invasion by 47.8% but also decreased expression of matrix metalloproteinase (MMP)-2 and -9. Vascular endothelial growth factor (VEGF) production from CT26 cells was also inhibited by treatment with CAPE (6 microg/mL). Intraperitoneal injection of CAPE (10 mg/kg/day) in BALB/c mice reduced the pulmonary metastatic capacity of CT26 cells accompanied with a decreased plasma VEGF level. CAPE treatment also prolonged the survival of mice implanted with CT26 cells. These results indicate that CAPE has potential as an antimetastatic agent.     

Evaluation of corn fiber, cottonseed hulls, oat hulls and soybean hulls as roughage sources for ruminants

An in situ trial (randomized complete block design) using cows, and a site and extent of digestion trial (Latin square design) using sheep were conducted to study the potential of corn fiber (CF), cottonseed hulls (CSH), oat hulls (OH) and soybean hulls (SH) as roughage sources for ruminants. Two feedlot trials with steers and one with lambs (completely randomized design with factorial arrangements of treatments) were conducted to study the potential of CF and SH as energy supplements relative to corn. In situ rate of ruminal dry matter (DM) disappearance (3 to 36 h) and extent of DM disappearance (36 h) indicated that CF and SH were more fermentable in the rumen compared with OH or CSH, with SH being the most fermentable. Total tract digestibilities of DM, organic matter (OM), neutral detergent fiber (NDF) and acid detergent fiber (ADF) were above 70% for sheep fed CF and SH diets, and were 50% or less for sheep fed OH and CSH diets. A ranking of by-products in terms of nutritive value followed the trend: CF greater than SH greater than OH greater than CSH. Lamb feedlot trial data showed that CF was of similar nutritive value to corn and of higher nutritive value than SH at the 50% level of supplementation. Corn-fed lambs responded better than CF- or SH-fed lambs at the 70% level of supplementation. Data from steer feedlot trials showed that CF was of similar quality to corn and of higher quality than SH. Dramatic differences exist in by-product feed utilization by ruminants. All by-products tested appeared to have some usefulness as dietary components.     

Effects of tolazoline and yohimbine on xylazine-induced central nervous system depression, bradycardia, and tachypnea in sheep

We compared the ability of tolazoline and yohimbine to antagonize xylazine-induced central nervous system depression, bradycardia, and tachypnea in 9 ewes and 5 rams. Once a week for 3 weeks, each sheep received one IV treatment of 0.4 mg xylazine/kg, 0.4 mg xylazine/kg followed in 10 minutes by 2 mg tolazoline/kg, or 0.4 mg xylazine/kg followed in 10 minutes by 0.2 mg yohimbine/kg. The order of the 3 treatments in each sheep was randomized. Xylazine alone caused recumbency for 41.0 +/- 3.7 minutes (mean +/- SEM). Tolazoline and yohimbine shortened the xylazine-induced recumbency to 12.1 +/- 0.9 minutes and 18.1 +/- 1.5 minutes, respectively. Sheep given xylazine alone had head droop for 34.0 +/- 5.4 minutes after rising. Head drooping of sheep given tolazoline or yohimbine was reduced to 10.1 +/- 1.7 minutes and 14.2 +/- 1.7 minutes, respectively. Both tolazoline and yohimbine reversed the bradycardia and tachypnea that followed xylazine administration. No statistical differences in the rate and magnitude of the reversal were observed between the 2 drugs.     

Tissue Distribution of Enrofloxacin in Fingerling Rainbow Trout Oncorhynchus mykiss Following Different Doses of Oral Administration

Rainbow trout Oncorhynchus mykiss were fed a ration medicated to provide enrofloxacin (Baytrilo®, Bayer) at 2.5, 5.0, or 10.0 mg drug per kg fish per d either 5 or 10 d. Tissue Concentrations of enrofloxacin were measured in liver, kidney, muscle, skin, and serum during the medication period, and thereafter for a total of 30 d. Highest tissue concentrations were observed in fish medicated with 5 mg enrofloxacin per kg fish per d for 10 d. Tissue concentrations of anitmicrobial activity were found to exceed minimum inhibitory concentrations of enrofloxacin for several isolates of Aeromonas salmonicida and Renibacterium salmoninarum . Lower than expected tissue concentrations were observed for the 10 mg per kg fish per d doses, perhaps due to a lack of acceptance of the medicated ration. The results support evaluation of a 5 mg per kg fish dose to treat bacterial infections of salmonids under field conditions.     

Evaluation of an enzyme-linked immunosorbent assay for detection of Eperythrozoon suis antibodies in swine.

An ELISA was developed and tested to detect antibodies to Eperythrozoon suis in swine. Results were compared with those of the indirect hemagglutination (IHA) test. Antigen isolated from swine heavily infected with E suis was used for both tests. Comparison of the ELISA with the IHA test revealed a significant (P less than 0.001) correlation between results. Of 114 samples obtained from 9 swine infected with E suis, 87.7% were seropositive (titer greater than or equal to 200) via the ELISA, and 80.7% were seropositive (titer greater than or equal to 20) via the IHA test. The sensitivity of the ELISA was greater than that of the IHA test. All blood samples obtained from specific-pathogen-free swine tested negative for E suis antibody. Cross-reactions were not observed between E suis antigen and antisera against various swine and cattle disease agents using ELISA. We concluded that the ELISA may be used for rapid and effective diagnosis of infection with E suis in swine.     

Effects of supplemental vitamin E during the mature period on the reproduction performance of Taiwan Native Chicken cockerels

One-day-old Taiwan native male chicks were fed with maize-soybean rearing diets without supplemental vitamin E to 23 weeks of age. From 23 to 52 weeks of age, the cockerels (n = 90) were assigned at random to 5 dietary treatments and fed with maize-soybean diets supplemented with 0, 20, 40, 80 and 160 mg/kg of vitamin E (dl-alpha-tocopherol acetate). Pullets (225) of the same age were fed with standard diets throughout. They were artificially inseminated with one dose of 0.04 ml/bird intact and 5-fold diluted pooled semen at 31 to 43 weeks of age and at 49 weeks of age, respectively. The criteria evaluated included: semen quality, fertility and maximum and effective duration of fertility, blood characteristics, body and testes weight. Supplemental vitamin E did not affect cockerels' effective duration of fertility and percentage of fertility. However, when pullets were inseminated with diluted semen, supplementing 160 mg/kg vitamin E increased the maximum duration of fertility at 49 weeks of age. Cockerels receiving 40 to 160mg/kg supplements had higher sperm viability and motility after 39 weeks of age and those fed 80 mg/kg had higher sperm concentration at 39 weeks of age. Cockerels receiving supplements of more than 40 mg/kg vitamin E had higher body weight gain. Plasma cholesterol and testosterone were not affected by supplemental vitamin E. However, plasma luteinising hormone (LH) concentration was lower in cockerels fed 160 mg/kg. Lack of supplemental vitamin E over 39 weeks was associated with lower semen quality but did not reduce the proportion of fertile eggs laid by inseminated hens, perhaps because the insemination dose compensated for low sperm quality. We found that the maximum duration of fertility might be improved by supplementing 160 mg/kg vitamin E at 49 weeks of age.     

Serological Comparison and Molecular Characterization for Verification of Calla lily chlorotic spot virus as a New Tospovirus Species Belonging to Watermelon silver mottle virus Serogroup

ABSTRACT Calla lily chlorotic spot virus (CCSV) isolated from central Taiwan was recently identified as a tospovirus serologically but distantly related to Watermelon silver mottle virus (WSMoV). To clarify the serological relationship between the two viruses, rabbit polyclonal antibody (PAb) to CCSV and mouse monoclonal antibodies (MAbs) to WSMoV NP or CCSV NP were produced in this investigation, using purified nucleocapsid protein (NP) as immunogens. The PAb to CCSV NP reacted stronger with the homologous antigen than with the heterologous antigen, with much lower A(405) readings in indirect enzyme-linked immunosorbent assay (ELISA) and low-intensity banding in immunoblotting. MAbs produced to CCSV NP or WSMoV NP reacted specifically with the homologous antigens but not with the heterologous antigens in both ELISA and immunoblot analyses. The CCSV S RNA was determined to be 3,172 nucleotides in length, with an inverted repeat at the 5' and 3' ends and two open reading frames encoding the NP and a nonstructural (NSs) protein in an ambisense arrangement. A typical 3'-terminal sequence (5'-AUUGCUCU-3') that is shared by all members of the genus Tospovirus also is present in the CCSV S RNA. The CCSV NP and NSs protein share low amino acid identities of 20.1 to 65.1% and 19.9 to 66.1%, respectively, with those of reported tospoviruses. Phylogenetic dendrogram analysis indicates that CCSV is a distinct member in the genus Tospovirus. The results provide evidence that CCSV is a new species in the genus Tospovirus and belongs to WSMoV serogroup.