Glucosinolate metabolism,functionality and breeding for the improvement of Brassicaceae vegetables

Unique secondary metabolites, glucosinolates (S-glucopyranosyl thiohydroximates), are naturally occurring S-linked glucosides found mainly in Brassicaceae plants. They are enzymatically hydrolyzed to produce sulfate ions, D-glucose, and characteristic degradation products such as isothiocyanates. The functions of glucosinolates in the plants remain unclear, but isothiocyanates possessing a pungent or irritating taste and odor might be associated with plant defense from microbes. Isothiocyanates have been studied extensively in experimental in vitro and in vivo carcinogenesis models for their cancer chemopreventive properties. The beneficial isothiocyanates, glucosinolates that are functional for supporting human health, have received attention from many scientists studying plant breeding, plant physiology, plant genetics, and food functionality. This review presents a summary of recent topics related with glucosinolates in the Brassica family, along with a summary of the chemicals, metabolism, and genes of glucosinolates in Brassicaceae. The bioavailabilities of isothiocyanates from certain functional glucosinolates and the importance of breeding will be described with emphasis on glucosinolates.     

Digestibility of common reed (Pharagmites communis Trin.) silage as ruminant feed and effects of inclusion levels in the diet of breeding cows on feed intake,ruminal fermentation and blood metabolites

To examine the digestibility of common reed (Pharagmites communis Trin.) silage and effects of inclusion levels in the diet of breeding cows on nutrient intakes, ruminal fermentation and nutrient status, two digestion trials using four sheep and cows, respectively, at the maintenance stage were conducted. In the trial using sheep, common reed silage contained 20% crude protein (CP) and 50% total digestible nutrients (TDN) on a dry matter basis. In the trial using cows, treatments were the control (92.4% Sudangrass hay and 7.6% soybean meal) and CS25, CS50 and CS80 (replacing 25%, 50%, and 80% of the control with silage, respectively). The intake and sufficiency rate of CP increased by increasing the silage level in the diet (P < 0.05), and the CP requirements of cows at maintenance was satisfied in CS80. In contrast, the sufficiency rate of TDN decreased in CS80, although it was 99.8%. Ruminal pH and NH₃‐N concentration changed among the treatments (P < 0.05); however, the blood metabolites were not affected by silage. The results indicated that including common reed silage of up to 80% in the diet of breeding cows was possible and did not have adverse effects on the blood metabolites.     

A stochastic model for behaviour of fish ascending an agricultural drainage system

Adults of Carassius auratus grandoculis ascend from Lake Biwa, Japan, into riparian paddy fields via agricultural drainage systems for the purpose of spawning. However, land improvement works conducted in the second half of the twentieth century have brought about obstacles for passage of the fish, and several restoration projects to recover the migratory environment are being attempted. A continuous Markov process model is presented to scientifically support such a project, defining an ascending probability that quantitatively assesses the ability of an agricultural drainage system with hydraulic structures for the ascent of the fish. Computational methods are developed to numerically obtain flow fields of the agricultural drainage system and then the ascending probability in the entire spatio-temporal domain. The values of model parameters are deductively inferred, referring to results of field observations. From the computational results of the ascending probability in the agricultural drainage system, effects of hydraulic structures allowing ascent of the fish are clarified.     

Development and application of loop-mediated isothermal amplification methods targeting the seM gene for detection of Streptococcus equi subsp. equi

Loop-mediated isothermal amplification (LAMP) constitutes a potentially valuable diagnostic tool for rapid diagnosis of contagious diseases. In this study, we developed a novel LAMP method (seM-LAMP) to detect the seM gene of Streptococcus equi subsp. equi (S. equi), the causative agent of strangles in equids. The seM-LAMP successfully amplified the target sequence of the seM gene at 63°C within 60 min. The sensitivity of the seM-LAMP was slightly lower than the 2nd reaction of the seM semi-nested PCR. To evaluate the species specificity of the seM-LAMP, we tested 100 S. equi and 189 non-S. equi strains. Significant amplification of the DNA originating from S. equi was observed within 60 min incubation, but no amplification of non-S. equi DNA occurred. The results were identical to those of seM semi-nested PCR. To investigate the clinical usefulness of the methods, the seM-LAMP and the seM semi-nested PCR were used to screen 590 nasal swabs obtained during an outbreak of strangles. Both methods showed that 79 and 511 swabs were S. equi positive and negative, respectively, and the results were identical to those of the culture examination. These results indicate that the seM-LAMP is potentially useful for the reliable routine diagnosis of Streptococcus equi subsp. equi infections.     

Spectral sensitivity of juvenile chub mackerel (<Emphasis Type="Italic">Scomber japonicus</Emphasis>) in visible and ultraviolet light

Although chub mackerel (Scomber japonicus) is widely distributed all over the world, the relevance of its visual sensitivity to its ecology is not yet fully understood. We investigated spectral sensitivity in juvenile chub mackerel in the range of ultraviolet (UV) to visible light (369–652 nm) by electroretinogram (ERG) using light-emitting diodes (LEDs). Sensitivity peaked at a wavelength of approximately 482 nm in dark-adapted fish and 525 nm in light-adapted fish. A secondary sensitivity peak in the UV range at approximately 382 nm was found in both dark- and light-adapted fish. The UV sensitivity of chub mackerel may be attributable to UV transmissibility of the optical media and to the presence of a beta-band of visible light-sensitive visual pigments, and not to an alpha-band of UV visual pigments. This UV sensitivity may be useful for feeding or communication with other fishes.     

Histochemical observations on the enzymes of chicken yolk sac membrane

In the endodermal cells of the yolk sac membrane of chicken embryos incubated for 12 to 18 d, the activity of glucose‐6‐phosphatase (G‐6‐Pase) was high, the activity of acid phosphatase (Acid Pase) was moderate, the activities of lactate dehydrogenase (LDH) and of glyceraldehyde‐3‐phosphate dehydrogenase (G‐3‐PDH) were low, and succinate dehydrogenase (SDH) and alkaline phosphatase (Alk Pase) activities were not detected. On the day before hatching, however, SDH became evident with low activity, and the activities of Acid Pase, LDH and G‐3‐PDH increased and remained higher until the day after. Five days after hatching, there were marked decreases in the activities of all the enzymes except SDH. Alk Pase was not detected at any time. The function of the yolk sac endo‐derm in the absorption of yolk is discussed in the light of these observations.     

Effect of dietary sodium bicarbonate and magnesium oxide on cows with milk fat depression in several dairy herds

Buffer mainly consisting of 100 g of sodium bicarbonate and 30 g of magnesium oxide was added to the feed per head per day and given for 8 months to groups of 92 cows of milk fat depression. Milk fat increased from 3.06% (pre-treatment) to 3.68% at 4 months and 3.71% at 8 months post-treatment. Solids-not-fat was slightly increased by the buffers. Milk production was not affected. The number of rumen protozoa increased from 2.85 X 10(5)/ml (pre-treatment) to 9.61 X 10(5)/ml at 8 months post-treatment and the kinds of protozoa diversified. An increase of acetate and decrease of propionate were observed together with increased milk fat at 8 months post-treatment. An increase of hematocrit, lactate dehydrogenase, sodium and potassium, and a decrease of cholesterol and gamma-glutamyl transpeptidase in blood were recognized after the treatment. The incidence of disease was reduced. There was a significant correlation between increased milk fat percentage and increase in the number and the kinds of protozoa.     

Histochemical demonstration of enzymes in the uropygial gland of the fowl

From the distribution of enzymes, the alveoli of a uropygial gland may be divided into inner and outer zones ; the former being the region near the cavity, and the latter the peripheral region of the gland.

In the inner zone, there appeared strong activities of 17β‐hydroxy‐steroid dehydrogenase (17β‐OH‐SDH), 30α‐OH‐SDH, glucose‐6‐phosphate dehydrogenase (G‐6‐PDH), lactate dehydrogenase (LDH), NAD‐dependent malate dehydrogenase (MDH) and acid phosphatase (Acid Pase) weak activities of succinate dehydrogenase (SuDH), NADP‐dependent MDH, monoamine oxidase (MAO) and non‐specific esterase (Etase), but no activity of β‐hydroxybutyrate dehydrogenase (β‐HbDH).

In the outer zone, there appeared strong activities of LDH and MDH (NAD), moderate activities of 17β‐OH‐SDH, 3α‐OH‐SDH, G‐6‐PDH and β‐HbDH, weak activities of SuDH, MDH (NADP) and MAO, but no activities of Etase and Acid Pase.

The results were negative concerning ?⁵‐3β‐OH‐SDH, glutamate dehydrogenase, a‐glycerophosphate dehydrogenase, phosphorylase and alkaline phosphatase in both zones. From these results, it was concluded that there must be functional differences between the zones, and that only a part of the metabolic pathways of steroids is being performed.