Isolation and structural identification of insecticidal compounds from Tripterygium wilfordii.

Five compounds were identified from Tripterygium wilfordii, including two novel compounds and three previously known compounds. Two newly discovered compounds are celangulin CY (1α,2α,3ß,4ß,6ß,8α,13-hepacetoxy-9ß-benzoyloxy-ß-dihydroagarofuran) and celangulin CQ (1α-nicotinoyloxy-2α,3ß,6ß-triacetoxy-9ß-furancarbonyloxy-13-isobutanoyloxy-4ß-hydroxy-ß-dihydroagarofuran). Their structures were determined using nuclear magnetic resonance (NMR), mass spectrometry (MS), and high-pressure liquid chromatography (HPLC). The isolated compounds were tested for insecticidal activity against the third instar larvae of Spodoptera frugiperda. Both celangulin CY and celangulin CQ exhibited significantly higher oral toxicity in the larvae than that exhibited by the three known compounds.

Two new compounds from the roots of Pueraria peduncularis and their molluscicidal effects on Pomacea canaliculata.

Two oleanane-type triterpenoid saponins named pedunsaponin D (1) and pedunsaponin E (2) were isolated from the roots of Pueraria peduncularis. The structures of the new compounds were elucidated based on chemical and physicochemical evidence as follows: pedunsaponin D, 3-O-ß-glucopyranosyl-(1-3)-ß-glucuronopyranosyl-3ß,15α,23α-trihydroxy-11,13(18)-oleanadien-16-one (1); pedunsaponin E, 3-O-ß-glucopyranosyl-(1-2)-ß-glucopy ranosyl(1-2)[ß-glucopyranosyl(1-3)-ß-glucuronopyranosyl]-3ß-hydroxy-16-oxoolean-12-en-30-oic acid (2). The two compounds showed moderate molluscicidal activity.[Formula: see text].

Bioinformatic and biochemical analysis of the key binding sites of the pheromone binding protein of Cyrtotrachelus buqueti Guerin-Meneville (Coleoptera: Curculionidea).

The bamboo snout beetle Cyrtotrachelus buqueti is a widely distributed wood-boring pest found in China, and its larvae cause significant economic losses because this beetle targets a wide range of host plants. A potential pest management measure of this beetle involves regulating olfactory chemoreceptors. In the process of olfactory recognition, pheromone-binding proteins (PBPs) play an important role. Homology modeling and molecular docking were conducted in this study for the interaction between CbuqPBP1 and dibutyl phthalate to better understand the relationship between PBP structures and their ligands. Site-directed mutagenesis and binding experiments were combined to identify the binding sites of CbuqPBP1 and to explore its ligand-binding mechanism. The 3D structural model of CbuqPBP1 has six a-helices. Five of these a-helices adopt an antiparallel arrangement to form an internal ligand-binding pocket. When docking dibutyl phthalate within the active site of CbuqPBP1, a CH-π interaction between the benzene ring of dibutyl phthalate and Phe69 was observed, and a weak hydrogen bond formed between the ester carbonyl oxygen and His53. Thus, Phe69 and His53 are predicted to be important residues of CbuqPBP1 involved in ligand recognition. Site-directed mutagenesis and fluorescence assays with a His53Ala CbuqPBP1 mutant showed no affinity toward ligands. Mutation of Phe69 only affected binding of CbuqPBP1 to cedar camphor. Thus, His53 (Between α2 and α3) of CbuqPBP1 appears to be a key binding site residue, and Phe69 (Located at α3) is a very important binding site for particular ligand interactions.

The effects of local variation in light availability on pollinator visitation, pollen and resource limitation of female reproduction in Hosta ventricosa.

BACKGROUND: Light availability may have direct effects on reproduction through resource availability, and indirect effects on female reproduction by influencing plant-pollinator interactions. Floral display size, pollinator visitation per flower, resource and pollen limitation of fruit and seed production were quantified in a forested patch and an adjacent open patch of two populations of the perennial herb Hosta ventricosa. RESULTS: Plants in the open patch produced significantly larger floral displays than those in the forested patch in both populations. Floral display size had a positive effect on pollinator visitation rate per flower in one population, but no effect in the other. Plants in the open patch received approximately 8-11 times more visitation rates and produced significantly more fruit and seeds per flower than those in the forested patch. However, supplemental pollination resulted in significantly more fruit and seed production per flower compared to natural pollination in the forested patch but not in the open patch in one population, and did not enhance fruit and seed production in either the forested or the open patch in the other. In both populations, supplementally pollinated plants in the open patch produced significantly more fruit and seeds per flower than supplementally pollinated plants in the forested patch. CONCLUSIONS: In H. ventricosa, local variation in light conditions could affect pollinator activity and influence female reproduction through resource availability; however differences in the degree of pollen limitation between local habitats were found to be population-specific.

Adsorption of emerging contaminant metformin using graphene oxide.

The occurrence of emerging contaminants in our water resources poses potential threats to the livings. Due to the poor treatment in wastewater management, treatment technologies are needed to effectively remove these products for living organism safety. In this study, Graphene oxide (GO) was tested for the first time for its capacity to remove a kind of emerging wastewater contaminants, metformin. The research was conducted by using a series of systematic adsorption and kinetic experiments. The results indicated that GO could rapidly and efficiently reduce the concentration of metformin, which could provide a solution in handling this problem. The uptake of metformin on the graphene oxide was strongly dependent on temperature, pH, ionic strength, and background electrolyte. The adsorption kinetic experiments revealed that almost 80% removal of metformin was achieved within 20 min for all the doses studied, corresponding to the relatively high k1 (0.232 min-1) and k2 (0.007 g mg-1 min-1) values in the kinetic models. It indicated that the highest adsorption capacity in the investigated range (qm) of GO for metformin was at pH 6.0 and 288 K. Thermodynamic study indicated that the adsorption was a spontaneous (ΔG0 < 0) and exothermic (ΔH0 < 0) process. The adsorption of metformin increased when the pH values changed from 4.0 to 6.0, and decreased adsorption were observed at pH 6.0-11.0. GO still exhibited excellent adsorption capacity after several desorption/adsorption cycles. Besides, both so-called π-π interactions and hydrogen bonds might be mainly responsible for the adsorption of metformin onto GO.

Effects of Scleroderma sichuanensis Xiao (Hymenoptera: Bethylidae) venom and parasitism on nutritional content regulation in host Tenebrio molitor L. (Coleoptera: Tenebrionidae).

To explore the mechanisms by which the wasp Scleroderma sichuanensis Xiao regulates the physiology and biochemistry of its host, effects of S. sichuanensis venom and parasitism on host the Tenebrio molitor L. pupae were examined. Significant differences in nutritional content were noted between parasitized and non-parasitized pupae and between venom- and phosphate buffered saline-injected pupae. When pupae were injected with venom, the fat body could not be disintegrated into granules; however, when pupae were parasitized, fat-body disintegration occurred. Electrophoresis showed no differences in hemolymph protein content between parasitized pupae and those injected with venom, indicating that the wasp did not have narrow-spectrum peptides. These findings confirmed that S. sichuanensis was a typical idiobiont ectoparasitoid wasp, and that nutrient regulation was similar between idiobiont and koinobiont wasps. The strong similarities between the two treatments suggest that venom injection is a major factor responsible for changes in host nutrient content. The wasp fed mainly on reducing sugars, free amino acids, and fat-body tissues; larval fat bodies were derived from hemolymph and from host tissue. Our findings suggest that lipid catabolism might be accelerated, and that lipid biosynthesis might be inhibited, when host pupae are parasitized or injected with venom. In addition to venom, physiological and biochemical changes that occur during the parasitic process might be caused by venom, ovarian proteins, saliva, or secretions.

[Treatment of pectin wastewater by anaerobic biological process].

Anaerobic biological process was used to treat pectin wastewater with acclimated sludge. The effects of the influent pectin concentration and the degradation temperature were investigated, and the intermediate products in pectin degradation were measured. Compared with the unacclimated sludge, the results showed that using acclimated sludge, the pectin removal efficiency was increased by 59.2%. The degradation rate of pectin at influent concentrations of 100, 2500 and 4500 mg x L(-1) were 4.5, 49.8 and 74.0 mg x (L x h)(-1), respectively, indicating that the degradation rate increased with the increase of the influent pectin concentration. The COD removal efficiency was relatively low (41.6% -82.0%) when the influent pectin concentration was lower than 500 mg x L(-1), but it could maintain above 91% when the influent pectin concentration was beyond 1000 mg x L(-1). The higher the temperature was, the shorter the time was needed for pectin degradation. The COD removal efficiency of anaerobic sludge for pectin wastewater was increased from 38.6% to 91.5% when the temperature ranged from 5 degrees C to 35 degrees C, but it was gradually weakened when the temperature exceeded 35 degrees C. The main intermediate products in pectin degradation were supposed to be acetic acid, propionic acid, lower ester, and alkyl alcohols (C12-C40).

Scale-dependent effects of habitat fragmentation on reproduction in the annual Circaeaster agristis, a narrow endemic and threatened species.

BACKGROUND: Habitat fragmentation and the resulting decline in population size and density commonly reduce the reproduction of rare and threatened species. We investigated the impacts of population size and density on reproduction in more than 30 populations of Circaeaster agristis, a narrow endemic and threatened species, in 2010 and 2011. We also examined the effects of NND (nearest neighbor distance) and LNS (local neighbor size), within radii of 0.1 m, 0.2 m and 0.3 m, on reproduction in two of the populations in 2011. RESULTS: Population size did not affect fruit (seed) number and fruit set in either year studied. Population density had an indirect negative effect on fruit number and fruit set as a consequence of a negative effect on plant size in 2010, but had no effect on fruit number and fruit set in 2011. Within populations, individual fruit number did not change, and individual fruit set increased independent of plant size, in response to increasing NND. Both individual fruit number and individual fruit set increased, independent of plant size, with increases in LNS within a 0.1 m radius, but did not change with increases in LNS within radii of between 0.1 m and 0.2 m radii or between 0.2 m and 0.3 m. CONCLUSIONS: The effect of habitat fragmentation on reproduction of C. agristis is scale-dependent. In contrast to the generally accepted idea that fragmentation reduces plant reproduction, reproductive success may increase in sparse populations or increase in response to decreases in LNS in C. agristis.

Electrophysiological and behavioral responses of the whitestriped longhorned beetle, Batocera lineolata, to the diurnal rhythm of host plant volatiles of holly, Viburnum awabuki.

The adsorption method of Tenax-TA absorbent with GC-MS was used to analyze diurnal rhythms of volatiles from undamaged holly plants, Viburnum awabuki Kock (Dipsacales: Adoxaceae) holly infested by the white-striped longhorned beetle, Batocera lineolata Chevrolat (Coleoptera: Cerambycidae). Electroantennography and a Y-tube olfactometer were used to compare and analyze electroantennogram and behavioral responses of unmated male and female adults to the volatiles from V. awabuki (both undamaged and infested plants). The results of the GC-MS analysis showed that phytosterol and alkane are major volatiles for V. awabuki. The relative content of V. awabuki volatiles changed during the day. Electroantennogram and behavioral responses of unmated male and female adults to the volatiles from both undamaged and infested plants of V. awabuki were stronger between 08:00 and 10:00 and 16:00 and 18:00, which is consistent with early morning and evening feeding behaviors of adults in the field.

[Effects of venom from Sclerodermus sichuanensis Xiao on pupa of Tenebrio molitor].

To explore the regulatory mechanisms of parasitism of Sclerodermus sichuanensis on Tenebrio molitor, the methods of natural parasitism and venom injection were adopted to investigate the effects of the venom from S. sichuanensis on the pupa of T. molitor in the parasitic process. Under venom injection, the paralytic degree of the pupa had a positive correlation with the concentration of injected venom, and the number of recovered pupa had a negative correlation with the injected venom concentration. The T. molitor pupa was in slight and reversible paralysis when injected with 0.01 VRE (venom reservoir equivalent) of venom, and in non-reversible and complete paralysis when 0.2 VRE was injected. The pupa died massively and appeared a wide range of melanization when injected with soil bacterial suspension alone, but the melanization delayed and the mortality declined significantly when the mixed liquor of bacterium and venom was injected. The bacteriostasis of the venom on Staphylococcus aureus was significantly stronger than that on Escherichia coli. Within a definite range of temperature, the paralytic activity decreased significantly with increasing temperature, the bacteriostasis on S. aureus increased significantly, while that on E. coli was opposite. This study showed that the venom from S. sichuanensis had the effects of paralysis, bacteriostasis, inhibiting exuviations, and delaying melanization.

[Biological phosphorus removal in intermittent aerated biological filter].

Under intermittent aerated and continuous fed operation where the biofilm system was subjected to alternated anaerobic/aerobic condition, the effect of influent volatile fatty acids (VFAs) concentrations, operation cycle and backwash on the biological phosphorus removal performance of the biofilter was studied. In the experiment, synthetic domestic wastewater was used, and the influent velocity was 5 L x h(-1) with gas versus liquid ratio of 8:1 and hydraulic retention time (HRT) of 1.3 h, resulting in average COD, ammonium and phosphorus load of 4.7, 0.41 and 0.095 g x (L x d) (-1) respectively. Results show that, (1) effective release and uptake of phosphorus was achieved in a operation cycle; (2) when influent VFAs was 100 mg x L(-1) (calculated by COD value) and operation cycle was 6 h the filter performed best in phosphorus removal, the phosphorus loading removal rate can be as much as 0.059 g x (L x d)(-1) at the aerated phase with those of COD and ammonium being 3.8 g x (L x d)(-1) and 0.28 g x (L x d)(-1) respectively, and with average effluent phosphorus, COD and ammonium concentrations being 1.8, 43.6 and 8.7 mg x L(-1), which shows nitrogen loss also happened; (3) the pause of backwash decreased the phosphorus removal performance rapidly with the removal efficiency lower than 40% in two days, but the consequent daily backwash operation gave a short improvement on the phosphorus removal, which disappeared in another two days. Thus, it is shown that biological phosphorus removal achieved with better phosphorus loading removal performance in the biofilter under intermittent aerated and continuous fed operation, and that sufficient and stable influent VFAs concentration, proper operation cycle, and more frequent backwash favored the performance.

[Diurnal rhythm of Viburnum awabuki and Betula luminifera volatiles and electroantennogram response of Batocera horsfieldi].

By the method of Tenax-TA absorbent adsorption combined with GC-MS, this paper analyzed the changes of the diurnal rhythm of the volatiles in the healthy branches and Batocera horsfieldi-damaged branches of Viburnum awabuki and Betula luminifera, and electroantennogram technique was used to perform a comparative analysis on the electroantennogram (EAG) responses of unmated male and female B. horsfieldi to the volatiles. After the feeding by B. horsfieldi, there was a decrease in the contents of limonene, nonanal, hexadecane, butyl acrylate, and 3-methyl-butanoic acid in damaged branches of V. awabuki and in the neohexane and hexadecane contents in damaged branches of B. luminifera. Simultaneously, new materials such as permethyl 99A, octyl alcohol, iodo, decanal, hexanal, and bioallethrin etc. were newly synthesized in the damaged branches. The EAG response values of unmated male and female B. horsfieldi adults to the volatiles in the damaged branches of B. luminifera were the highest, being 1.23 mV and 1.38 mV, while to the healthy branches of V. awabuki were the lowest, being 0.95 mV and 1.01 mV, respectively. As for the time period, the EAG response values of the adults to the volatiles were the lowest from 12:00 to 14:00, which accorded with the feeding behaviors of the adults, i. e., taking food in the field in early morning or at dusk.

[Performance of desulfurizing absorbent of roasted navajoite].

An innovative flue gas desulfurization (FGD) coupling process was proposed in this study to overcome the problems in wet-type limestone/lime processes which include fouling, clogging, and difficulty of selling the by-products and the problems in traditional process for vanadium extraction from navajoite ore such as excessive consumption of sulfuric acid and emissions of pollutants. The performance of a jet bubbling reactor (JBR) at pilot-scale was evaluated using navajoite ore produced in the process of extracting vanadium pentoxide as desulfurization absorbent. Results showed that navajoite ore slurry achieved better desulfurization performance than limestone slurry. When the inlet flue gas pressure drop was 3.0 kPa, the gas flow was about 2350 m3 x h(-1) and the pH of the navajoite ore slurry was higher than 4.5, the desulfurization efficiency was stable about 90%. The SO2 removal efficiency appeared to increase along with the increasing of absorbent cycle-index. The efficiency of the second circulation was improved 3.5% compared to the first circulation. After an operating duration of 40 minutes, the leaching rate of vanadium pentoxide was about 20%, and reached 60% when the by-products were leached with 5% dilute sulfuric acid for 10 hours. The by-product from this process not only could be used to produce vanadium pentoxide which is a valuable industrial product, but also could significantly overcome the pollution problem existing in the traditional refining process of vanadium pentoxide when navajoite ore is used as the feed material. This FGD process using roasted navajoite slurry as absorbent is environmental sound and cost-effective, and shows the potential for application in the field of flue gas desulfurization as well as hydrometallurgy.

Efficacy of nasal irrigation in the treatment of acute sinusitis in children.

BACKGROUND: Nasal irrigation has been used as an adjunctive therapy of sinonasal disease including acute/chronic sinusitis and allergic rhinitis. Several published articles reported it also improves clinical sinus symptoms. OBJECTIVE: To evaluate the effectiveness of normal saline nasal irrigation in the management of acute sinusitis in children. DESIGN: This was a randomized, prospective placebo-controlled study. METHODS: We included 69 participants with acute sinusitis. 30 of 69 participants underwent normal saline nasal irrigation. 39 of 69 participants were not receiving nasal irrigation. All participants performed nasal peak expiratory flow rate (nPEFR) test, nasal smear examination, radiography (Water's projection) and requested to complete the Pediatric Rhinoconjunctivitis Quality of Life Questionnaires (PRQLQ) at the baseline visit. All participants were requested to record the symptom diary card every day and were followed-up every 1 week during this period. A physical examination, nasal smear and nPEFR were performed at each visit, and all daily diary cards collected. At the final visit, the symptoms diaries were reviewed and participants were requested to complete the PRQLQ again. The nPEFR, radiography (Water's projection) and nasal smear were also repeated. RESULTS: Normal saline irrigation group significantly improved mean PRQLQ values and nPEFR values at medium (T=2.816, P<0.05) and final period (T=2.767, P<0.05) compared with the other group. Although there were no statically significant improving rate of radiography (Water's projection) in among two groups (T=0.545, P>0.05), but normal saline irrigation group was better than the other group. The improval rate of mean TSS in the irrigation group significantly improved all symptoms compared with the placebo group, in which rhinorrhea, nasal congestion, throat itching, cough and sleep quality improved. 27 of 66 (40.9%) participants with atopy, 16 of 27 (53.33%) participants underwent normal saline irrigation. Normal saline irrigation atopy group significantly improved rhinorrhea, nasal congestion, throat itching and sleep quality symptoms compared with non-irrigation atopy group. Normal saline irrigation atopy group significantly improved nPEFR values at final period (Z=2.53, P<0.05). CONCLUSION: This study evidence that normal saline nasal irrigation improves Pediatric Rhinoconjunctivitis Quality of Life and decreases acute sinusitis symptoms. Nasal irrigation is an effective adjunctive treatment for pediatric acute sinusitis. Normal saline nasal irrigation in atopy children also improves allergic-related symptoms. We may need larger, longer and extended study to assess the conclusion.

Removal of cationic dyes from aqueous solution using magnetic multi-wall carbon nanotube nanocomposite as adsorbent.

A magnetic multi-wall carbon nanotube (MMWCNT) nanocomposite was synthesized and was used as an adsorbent for removal of cationic dyes from aqueous solutions. The MMWCNT nanocomposite was composed of commercial multi-wall carbon nanotubes and iron oxide nanoparticles. The properties of this magnetic adsorbent were characterized by scanning electron microscopy, X-ray diffraction and BET surface area measurements. Adsorption characteristics of the MMWCNT nanocomposite adsorbent were examined using methylene blue, neutral red and brilliant cresyl blue as adsorbates. Experiments were carried out to investigate adsorption kinetics, adsorption capacity of the adsorbent and the effect of adsorption dosage and solution pH values on the removal of cationic dyes. Kinetic data were well fitted by a pseudo second-order model. Freundlich model was used to study the adsorption isotherms. The prepared MMWCNT adsorbent displayed the main advantage of separation convenience compared to the present adsorption treatment.

Identification of a liver-specific cAMP response element in the human argininosuccinate synthetase gene.

Argininosuccinate synthetase (ASS), a key enzyme in the urea cycle, participates in many metabolic processes including arginine biosynthesis and the citrulline-nitric oxide (NO) cycle. Factors like diets, hormones and pro-inflammatory stimuli are known to regulate ASS gene expression primarily at the transcription level. However, little is known about the cis-elements for transcriptional regulation of the ASS gene. In this study, we employed DNase I hypersensitive sites mapping to identify potential regulatory sites of the gene and revealed a site located at 10 kb upstream of the transcription start site which is responsible for liver-specific cAMP induction. Furthermore, a cAMP response element (CRE) highly conserved among mammals was identified and was experimentally verified. Our results show that liver-specific enhancement of ASS gene expression is mediated in part by the cAMP signaling pathway through a distal CRE site.

Transgenic CD4 T cells (DO11.10) are destroyed in MHC-compatible hosts by NK cells and CD8 T cells.

During an immune response a small number of rare Ag-specific clones proliferate extensively and decline, leaving a residual population for long-term memory. TCR transgenic (tg) CD4 T cells have been used widely to study the primary and memory response in vivo. We show here that naive TCR tg CD4 T cells from the DO11.10 strain transferred into wild type (wt) BALB/c recipients and not stimulated declined rapidly at the same rate as those primed in vivo by Ag. In the same recipients wt CD4 T cells survived. There was no evidence of an inherent defect in the tg T cells, which survived well when returned to DO11.10 recipients. Surprisingly, wt CD4 T cells declined rapidly in the same DO11.10 hosts. By depleting wt recipients of NK cells or CD8+ cells, the speed of reduction was slowed by half; rapid destruction was prevented completely by combing the two treatments. In contrast, preimmunization accelerated the loss of tg T cells. The results suggested that tg CD4 T cells were actively rejected by both NK and CD8 T cell responses. We consider whether, despite extensive backcrossing, tg T cells may retain genetic material (minor histocompatibility Ags) flanking the construct that compromises their survival in wt recipients.

On the role of CD26 in CD4 memory T cells.

We studied an in vivo mouse model to evaluate the relationships between CD26--a glycoprotein with dipeptidyl peptidase IV (DPP-IV) activity implicated in the regulation of immune functions--and T cells expressing the effector/memory phenotype CD45RB. We report that CD26 does not define a differentiation stage of CD4 T cells because the density and frequency of CD26 on CD4 T cells from the spleen, inguinal and mesenteric lymph node was similar within the CD45RB+ (naïve) and CD45RB- (antigen primed) subsets. This observation was confirmed using CD4 T cells from a T-cell receptor transgenic (tg) model. CD4 tg T cells specific for ovalbumin (OVA) were adoptively transferred and challenged in vivo with antigen. CD26 expression was the same on naive and antigen-stimulated CD4 T cells. Depleting CD4 T cells with an anti-CD4 antibody preferentially depleted the CD45RB+ subset. In CD4 depleted animals CD26 expression was not altered on the CD45RB- subset but the density of CD26 was marginally increased on the remaining CD45RB+ CD4 T cells. The results suggest that, unlike the human, CD26 in the mouse was not directly linked with T cell activation.

Naive T-cell receptor transgenic T cells help memory B cells produce antibody.

Injection of the same antigen following primary immunization induces a classic secondary response characterized by a large quantity of high-affinity antibody of an immunoglobulin G class produced more rapidly than in the initial response - the products of memory B cells are qualitatively distinct from that of the original naive B lymphocytes. Very little is known of the help provided by the CD4 T cells that stimulate memory B cells. Using antigen-specific T-cell receptor transgenic CD4 T cells (DO11.10) as a source of help, we found that naive transgenic T cells stimulated memory B cells almost as well (in terms of quantity and speed) as transgenic T cells that had been recently primed. There was a direct correlation between serum antibody levels and the number of naive transgenic T cells transferred. Using T cells from transgenic interleukin-2-deficient mice we showed that interleukin-2 was not required for a secondary response, although it was necessary for a primary response. The results suggested that the signals delivered by CD4 T cells and required by memory B cells for their activation were common to both antigen-primed and naive CD4 T cells.

Inhibition of chronic vascular rejection by donor-specific blood transfusion is associated with a reduction in transforming growth factor-beta1 expression.

BACKGROUND: Concentric intimal thickening and the infiltration of inflammatory cells in cardiac allografts are the pathological hallmark characteristics of chronic vascular rejection (CVR), the leading cause of long-term graft failure. The precise mechanisms involved in the development and pathogenesis of CVR remain elusive. In the PVG-R23 to PVG-RT1u rat model of CVR, prior administration of a donor-specific transfusion (DST) was previously shown to prolong graft survival indefinitely and abolish the vascular lesions associated with CVR. The present study investigates in more depth the underlying mechanisms involved in the subsequent prolongation of allograft survival and inhibition of CVR by DST. METHODS: R23 heart grafts were monitored in nontransfused and transfused RT1u recipients injected 2 weeks before transplantation with 1.5 ml of R23 blood. Severity of arteriosclerosis, transplant infiltrate, transforming growth factor (TGF)-beta1 protein expression within the graft, plasma TGF-beta1 levels, class II MHC expression, tenascin protein expression, and serum alloantibody levels were measured. RESULTS: There was no significant difference in donor MHC class II, myocardial TGF-beta1, or tenascin expression between DST and non-DST-treated recipients. However, DST-pretreated recipients showed greatly reduced histological evidence of CVR and had lower titers of R23-specific IgG subclasses. Furthermore, DST-treated allograft recipients showed significant decreases in circulating TGF-beta1 levels and a reduction in TGF-beta1 and tenascin expression within coronary arteries of the allografts. CONCLUSION: The results suggested that DST inhibited CVR by altering and regulating the expression of TGF-beta1, thereby preventing the fibrogenic effects associated with TGF-beta1.