Analysis of acrylamide in green tea by gas chromatography-mass spectrometry

Optimization of the solid-phase extraction cleanup procedure enabled the GC-MS analysis of acrylamide in tea samples without the interference of bromination by tea catechins. Although polyvinylpolypyrrolidone (PVPP) is available for removing tea catechins from tea extract, the peaks derived from PVPP had the same retention time as brominated acrylamide in mass chromatograms obtained by GC-MS. A considerable amount of acrylamide was formed at roasting temperatures of > or =120 degrees C; the highest acrylamide level was observed when tea samples were roasted at 180 degrees C for 10 min. Higher temperatures and longer processing times caused a decrease in the acrylamide content. Furthermore, an analysis of 82 tea samples showed that rather than the reducing sugar content, the asparagine content in tea leaves was a significant factor related to acrylamide formation in roasted products. The acrylamide level in roasted tea products was controlled by asparagine in the presence of reducing sugars.     

Killing of feline T-lymphocytes by gamma-rays and energetic carbon ions

High linear energy transfer (LET) heavy charged particles have previously been applied clinically to human cancer radiotherapy because of their excellent physical properties of selective dose distribution and higher relative biological effectiveness (RBE) for human; however, such an approach has yet to be applied to cat patients. The present study investigates the biological effectiveness of low-LET gamma-rays (0.2 keV/micro m) compared to high-LET carbon ions (114 keV/micro m) in feline T- lymphocyte FeT-J cells. Clonogenic survival analysis revealed that the RBE value of carbon ions was 2.98 relative to a 10% survival dose (D(10)) by gamma-rays, and that the inactivation cross-section in cells exposed to gamma-rays and carbon ions was 0.023 and 38.9 micro m(2), respectively. Terminal deoxynucleotidyl transferase (TdT)-mediated dUTP-biotin nick end labeling (TUNEL) analysis revealed that TUNEL-positive frequency in carbon-irradiation cells is higher than for gamma-irradiated cells against exposure to the same physical doses, but that very little difference in TUNEL-positive frequency is observed between cells exposed to the respective D(10) dose of gamma-rays. Our data thus indicate that carbon ions are more effective for cell killing than gamma-rays at the same physical doses, but kill cells to an extent that is comparable to gamma-rays at the same biological doses. Carbon ion radiotherapy is therefore a promising modality for cat patients.     

Characterization of Erysipelothrix rhusiopathiae strains isolated from recent swine erysipelas outbreaks in Japan

The objective of the present study was to characterize Erysipelothrix sp. strains from recent erysipelas outbreaks in Japan. Eighty-three (100%) strains were identified as E. rhusiopathiae, based on serotyping and spaA PCR. Fifty (60.3%), 5 (6.0%), and 28 (33.7%) strains were isolated from animals with acute, subacute and chronic outbreaks, respectively, of which 79 (95.2%), 1 (1.2%), and 3 (3.6%) belonged to serotypes 1a, 2a, and untypeable, respectively. Fifteen strains (including 3, 2, and 10 from acute, subacute, and chronic cases, respectively) were sensitive to acriflavine, and showed high levels of virulence in mice; of which strains from acute cases, and from subacute and chronic cases killed 100%, and 80 to 100% mice, respectively at challenge doses of 10(2) CFU per mouse. Based on sequence analysis of a 432-bp hypervariable region in spaA gene, 83 strains could be divided into 3 groups: (i) group 1 (3 strains of serotype 1a) had Ala-195 and Ile-203; (ii) group 2 (76 strains of serotype 1a and 3 of untypeable) had Asp-195 and Met-203; and (iii) group 3 (one strain of serotype 2a) had Asn-195 and Ile-203. The results of the present study suggest that the serotype 1a strains belonging to the group 2 might be widespread in pig populations in Japan.     

Effectiveness of small interfering RNA (siRNA) against the Mcl-1 gene in a canine mammary gland tumor cell line

The effect of down-regulation of Mcl-1 expression by small interfering RNA (siRNA) against the canine Mcl-1 gene on apoptosis was investigated by transfecting CF33 (canine mammary gland tumor cell line) with siRNA using cationic liposomes. The siRNA against canine Mcl-1 increased the rate of apoptotic cells and decreased the numbers of viable cells. Further, sequence-specific down-regulation of Mcl-1 expression was measured by real time-PCR and Western blot analysis. The siRNA directed against the Mcl-1 gene reduced both the mRNA and protein expression in the CF33. Our study suggests the importance of Mcl-1 in canine mammary tumors for inducing apoptosis and reinforces using Mcl-1 as a putative therapeutic target in canine mammary gland tumor.     

First report of raspberry yellows disease caused by raspberry bushy dwarf virus in Japan

Severe yellowing of leaves was observed on red raspberry in Akita Prefecture. When inoculated with sap from symptomatic raspberry leaves, Chenopodium quinoa plants developed chlorotic ringspot and mottling that are typical of raspberry bushy dwarf virus (RBDV) infection. In western blot analysis, an antibody to the coat protein (CP) of RBDV reacted against ca. 30-kDa protein specific to the diseased trees. In RT-PCR testing for RBDV, single DNA fragments were amplified from total RNA samples of the diseased trees. The nucleotide sequences of the DNA fragments covering the entire CP region revealed 87–97?% identities with those of RBDV isolates.     

Influence of bacteriocin-like substance, generation times, and genetic profiles of Listeria innocua on the isolation of Listeria monocytogenes

Inhibition of isolation of Listeria monocytogenes by bacteriocin-like substance (BLS)-producing Listeria innocua after enrichment culture was investigated. When 26 L. monocytogenes strains were examined in combination with eight L. innocua strains using the spot on lawn method, 52/208 (25.0%) combinations showed the growth inhibition of L. monocytogenes. When two Listeria species were cultured simultaneously in selective enrichment broth, inhibition of isolation of L. monocytogenes was observed in 12/52 of the combinations at 24h (23.1%), in 24/52 at 48h (46.2%) and in 30/52 (57.7%) after 7 days of incubation. The randomly amplified polymorphic DNA profiles showed no interstrain similarities between either strains of the BLS-producing L. innocua or the BLS-sensitive L. monocytogenes strains. Therefore inhibition by BLS-producing L. innocua of isolation of L. monocytogenes after enrichment culture is unlikely to be dependent upon a particular genetic profile.     

The marked increase of Listeria monocytogenes isolation from contents of swine cecum

The actual prevalence of Listeria monocytogenes from contents of swine cecum was investigated. The efficiency of Listeria enrichment broth (LEB) for isolation was examined by the recovery of artificially inoculated L. monocytogenes in contents of swine cecum. The numbers of organisms did not increase after 48 h incubation, but increased when the rapid decrease in pH of the LEB was adjusted. Between 1991 and 1993, 250 contents of swine cecum were examined for the prevalence of L. monocytogenes using LEB enrichment, either with or without pH adjustment. L. monocytogenes was isolated from 74 samples in 1993 with pH adjustment, however, no organisms were isolated in 1991 and 1992. It was suggested that the marked rise of the L. monocytogenes isolation was due to the spread of the organism among swine. Furthermore, 67 out of the 74 isolates were identified as 1/2c by serotyping. The serovar 1/2c strains showed genetic diversity by random amplified polymorphic DNA.     

Microvasculature of the retina, ciliary processes and choroid in the North American raccoon (Procyon lotor) eye: a scanning electron microscopic study of corrosion casts

We have studied the vasculature of the retina, ciliary processes and choroid in the North American raccoon (Procyon lotor), a nocturnal mammal, using light and scanning electron microscopic examination of corrosion casts. We carried out an identical study in the crab-eating macaque (Macaca fascicularis), which forages only during the daytime, in order to compare the ocular vasculature with that of nocturnal mammals. Our observations in raccoons demonstrated a photoreceptor layer associated with rich lymph and a poorly vascularized retina. The meridian region of the eye, which lies in the horizontal plane and pass around the optic disc, had a markedly sparse capillary network. This horizontal sparse vascular band may correspond to a visual streak. Ciliary process capillaries were delicate, and formed a well-developed and compact network. Choriocapillaries were quite thin and formed a coarse capillary network. This contrasted with the dense retinal and well-extended choroidal capillary networks noted in the macaques. Our findings suggest that the sparse retinal capillary network in raccoons is extremely beneficial for photon capture, thereby allowing the raccoon to see well at night, as the retinal vessels restrict the inflow of photons toward the photoreceptors. The well-developed lymph probably compensates for the sparse retinal capillaries and choriocapillaries and nourishes the retina in the nocturnal raccoon.