Quantitative in vivo measurement of central benzodiazepine receptors in the brain of cats by use of positron-emission tomography and [11C]flumazenil

OBJECTIVE: To map central benzodiazepine receptors (BZRs) in the brain of cats by use of positron-emission tomography (PET) and [11C]flumazenil. ANIMALS: 6 male cats that weighed between 2.0 and 3.6 kg. PROCEDURE: Brain images obtained by PET evaluation of [11C]flumazenil were superimposed on T2-weighted magnetic-resonance imaging (MRI) scans of the same cats. Detailed anatomic regions, such as the cerebral cortex, striatum, thalamus, midbrain, and cerebellum, on the PET images were evident by PET-MRI registration. Regional binding of [11C]flumazenil to BZRs was quantitatively measured by use of a model with 2 tissue compartments and 4 variables. RESULTS: The highest value for distribution volume was observed in the cerebral cortex, and the lowest value was found in the midbrain of cats. CONCLUSIONS AND CLINICAL RELEVANCE: Binding of [11C]flumazenil to BZRs in the brain of cats can be quantitatively measured by use of PET with the aid of PET-MRI registration. It is difficult to diagnose changes in these neuroreceptors within the field of current veterinary science. In the future, PET should prove useful for investigating and diagnosing brain disorders in animals in clinical settings.     

A time-series data analysis to examine effects of subsidies to fishery productions in Japan

A cointegration analysis is conducted to examine the effect of fishery subsidies on fisheries production using data compiled over more than 30 years in Japan. The results illustrate that one fishery production indicator (production value per fishermen) shows a positive relationship with one particular group of government financial transfer (GFT) (that is, government general service expenditures including cost for fishery managements, scientific researches, and other administrative activities). No other tested results between GFTs and fishery indicators showed a real relationship. Although further scrutiny is awaited, this study could provide an empirical basis for an argument that, under an effective fishing management system, fisheries subsidies do not necessarily cause production increases or negative impact on fishing stocks.     

Evaluation of several wild tuber-bearingSolanum species for scab resistance

One hundred accessions of 18 wild diploid potato species were screened for resistance to scab through three cycles of selection, from which a total of 322 clones were selected as resistant. The putative ancestral species of the cultivated potatoes (Solanum bukasovii, S. canasense andS. multidissectum) produced resistant clones with significantly higher rates. Thus, these are primary gene sources for conferring scab resistance to cultivated potatoes.     

QTL for spikelet number from a high-yielding rice variety, Hoshiaoba, detected in an introgression line with the genetic background of an indica rice variety, IR64

Total spikelet number per panicle (TSN) is thought to be one of the most important agronomic traits associated with grain production in rice (Oryza sativa L.). We previously reported the development of 334 introgression lines (ILs) with variations in agronomic traits in the genetic background of indica rice variety IR64. Among these, an IL derived from high-yielding rice variety Hoshiaoba showed significantly higher TSN than IR64. We therefore have conducted a quantitative trait locus (QTL) analysis for TSN in an F₂ population of IL × IR64 to ascertain the genetic basis for the high TSN of the IL. The analysis revealed the presence of a QTL for TSN on chromosome 7, where several QTLs for grain number have been previously reported. We developed a near-isogenic line (NIL) for this QTL by using DNA marker-assisted selection and characterized its effect. The NIL showed significantly higher TSN than IR64. These results suggest that the QTL and the NIL will be useful materials in breeding programs aimed at increasing TSN.     

QTLs for phosphorus deficiency tolerance detected in upland NERICA varieties

Phosphorous (P) deficiency is a major yield limiting factor in rice (Oryza sativa L.) production. The interspecific New Rice for Africa (NERICA) varieties combine general stress tolerance from African cultivated rice (Oryza glaberrima Steud) with characteristics associated with high yield from O. sativa. However, little is known about their ability to tolerate P deficiency. Here, we examined the variation for tolerance to P deficiency among the 18 upland NERICAs and their parents in multi‐year field experiments. The good performance under P deficiency of the O. glaberrima parent CG 14 and some NERICAs suggested that these tolerant NERICAs contain loci associated with P deficiency tolerance inherited from CG 14. Additionally, four QTL clusters for P deficiency tolerance were detected on chromosomes 4, 6 and 11 using F₃ lines derived from the cross between the P deficiency tolerant variety NERICA10 and a Japonica‐type sensitive variety ‘Hitomebore’. These QTLs represent the first step in identifying stress tolerance genes from O. glaberrima that could subsequently be used to enhance P deficiency tolerance in O. sativa.     

Genotypic variation in grain phosphorus concentration,and opportunities to improve P-use efficiency in rice

Continual removal of phosphorus (P) from fields in rice grains at harvest results in lower soil fertility in low-input farming systems and drives the need for fertiliser inputs in high-input farming systems. High-P content in rice grains (the majority as phytate) contributes little to human nutrition and agronomic practices such as growing seedlings in high-P media or seed P coating at sowing (in direct-sown crops) may overcome the reported need for high-P seed for seedling establishment. Thus, reducing the amount of P in rice grains at maturity through breeding may represent a novel means to reduce ‘mining’ of soil P. We investigated the uptake and partitioning of P in rice plants and examined the scope for breeding rice with lower grain P by assessing genotypic variation for phosphorus harvest index (PHI) and seed P concentrations among a set of 38 rice genotypes in the field. At maturity approximately 75% of total plant P was found in grains and translocation of P from stems and leaves contributed substantially to grain P. However, unlike other cereals such as wheat, rice plants continued dry matter and P accumulation until maturity with approximately 40% of total plant P taken up post anthesis. In the field study, PHI differed significantly among genotypes (from 57 to 87) but was highly correlated to HI (P ≤ 0.001), suggesting that exploiting genotypic variation for this trait may be counterproductive. Grain P concentrations varied from 1.96 to 3.18 mg P g⁻¹, and were neither associated with reductions in grain yield or seed size, nor significantly correlated to HI. Grain P concentration therefore appears to be a suitable screening criterion and the 50% variation observed among genotypes suggests that scope exists for breeding rice with lower grain P concentration to reduce the off-take of P from rice fields at harvest.     

An improved hemagglutination test for study of canine parvovirus

Optimal conditions for hemagglutination (HA) by canine parvovirus (CPV) strains were investigated using several buffers. Porcine erythrocytes often agglutinated spontaneously in phosphate-buffered salt solution, isotonic saline solution or barbitone-complement-fixation buffer. Results were reproducible when borate-buffered saline (BBS) was used as the diluent for antigen, and "virus adjusting diluent" (VAD), containing 0.15 M NaCl and 0.3 M phosphate was used as the diluent for erythrocytes. Highest HA titers were obtained at pH 6.0 using BBS and VAD. Specific HA with CPV was observed not only at 4 degrees C but at 37 degrees C, and erythrocytes from horse, shrew mouse, hamster, cat, sheep and dog, as well as pig and African green monkey were agglutinated by CPV using the improved method.     

Non-steroidal inhibitors of Drosophila melanogaster steroidogenic glutathione S-transferase Noppera-bo

Insect growth regulators (IGRs) can be developed by elucidating the molecular mechanisms of insect-specific biological events. Because insect molting, and metamorphosis are controlled by ecdysteroids, their biosynthetic pathways can serve as targets for IGR development. The glutathione S-transferase Noppera-bo (Nobo), which is conserved in dipteran and lepidopteran species, plays an essential role in ecdysteroid biosynthesis. Our previous study using 17β-estradiol as a molecular probe revealed that Asp113 of Drosophila melanogaster Nobo (DmNobo) is essential for its biological function. However, to develop IGRs with a greater Nobo inhibitory activity than 17β-estradiol, further structural information is warranted. Here, we report five novel non-steroidal DmNobo inhibitors. Analysis of crystal structures of complexes revealed that DmNobo binds these inhibitors in an Asp113-independent manner. Among amino acid residues at the substrate-recognition site, conformation of conserved Phe39 was dynamically altered upon inhibitor binding. Therefore, these inhibitors can serve as seed compounds for IGR development.