CB1 cannabinoid receptors and on-demand defense against excitotoxicity

Abnormally high spiking activity can damage neurons. Signaling systems to protect neurons from the consequences of abnormal discharge activity have been postulated. We generated conditional mutant mice that lack expression of the cannabinoid receptor type 1 in principal forebrain neurons but not in adjacent inhibitory interneurons. In mutant mice,the excitotoxin kainic acid (KA) induced excessive seizures in vivo. The threshold to KA-induced neuronal excitation in vitro was severely reduced in hippocampal pyramidal neurons of mutants. KA administration rapidly raised hippocampal levels of anandamide and induced protective mechanisms in wild-type principal hippocampal neurons. These protective mechanisms could not be triggered in mutant mice. The endogenous cannabinoid system thus provides on-demand protection against acute excitotoxicity in central nervous system neurons.     

Utilizing expert panels in agricultural safety and health research

This article reports on the use of expert panels by Purdue University's Agricultural Safety and Health Program staff to address three separate research questions related to: (1) developing strategies for the prevention of flowing grain engulfments, (2) evaluation of commercial lifts used by operators with restricted mobility to gain access to agricultural tractors and equipment, and (3) identifying essential competencies for youth enrolled in federally mandated tractor and machinery certification programs. Advantages and disadvantages associated with the use of expert panels are addressed, and specific examples of outcomes are presented. Recommendations for using expert panels during research projects are also included.     

Changes in nitrogen compounds in must and wine during fermentation and biological aging by flor yeasts.

Urea, ammonium, and free amino acid contents were quantified in a must from Vitis vinifera cv. Pedro Ximenez grapes and in fermented wine and after a short aging of this wine by Saccharomyces cerevisiae race capensis yeast under variable oxygen availability conditions. The previous compounds were also determined in a wine in which the nitrogen source was depleted by the same race of flor yeast (old wine) and also following the addition of ammonium ion, L-glutamic acid, and L-proline. Under specific conditions such as low oxygen level and the absence of some nutrients, the yeasts release some amino acids including L-threonine, L-tryptophan, L-cysteine, and L-methionine to the medium. These amino acids must originate primarily in a de novo synthesis from ethanol that regenerates NAD(P)+. On the basis of these results, the yeasts may be able to use amino acids not only as nitrogen sources but also as redox agents to balance the oxidation-reduction potential under conditions of restricted oxygen, when electron transport along the respiratory chain may be hindered or limited.     

Comparison of homozygous and heterozygous self-compatible seedlings in an almond breeding programme

Homozygous self-compatible almond cultivars have not been reported. It is unclear if they are more inferior than heterozygotes or simply have not yet been detected. To investigate if homozygous individual are generally inferior, the self-compatibility genotype, homozygous or heterozygous, was determined by stylar ribonuclease assay in a population of 241 almond trees obtained by self-fertilisation of self-compatible selections. The resulting zymograms showed that 129 of the seedlings were homozygous and 112 heterozygous. For three years the differences observed between these two classes of self-compatible individuals were analysed with respect to 16 agronomic characteristics. In general, there were no important differences between the two classes. Both showed a low degree of productivity, probably as a result of their inbred origin. Some selected homozygous individuals were used in crosses, which were planned so as to ensure the self-compatibility of 100% of the descendants and to eliminate the laborious task of testing the seedlings for self-compatibility. This revised version was published online in August 2006 with corrections to the Cover Date.     

Use of recessive homozygous genotypes to assess genetic control of kernel bitterness in almond

Bitter flavour of the almond kernel is due to the cyanoglucoside amygdalin and has been the first characteristic considered in breeding programmes. In such programmes, the seedlings from sweet-kernelled parents were used to study the transmission of bitterness, which was shown to be a monogenic characteristic, the sweet flavour being dominant. The aim of this work was to investigate more deeply the inheritance of bitterness in almond, by studying for 2 consecutive years the bitter flavour in 169 seedlings of 9 families (obtained exclusively for this purpose), one or both parents being bitter-kernelled. With the exception of the presence of slightly bitter seedlings, the results support the hypothesis of monogenic inheritance of this trait, the bitter flavour being recessive, although other factors could have a slight influence on the expression of this characteristic. Heterozygous individuals showed sweet, slightly bitter or year-changeable (sweet-slightly bitter) phenotypes. Our results demonstrated the possibility of using as parents bitter-kernelled individuals with some outstanding characteristic desirable for transmission to the progeny, always in combination with a homozygous sweet progenitor.     

New inheritance studies related to Potato Virus Y (PVY) resistance in Capsicum annuum L. ‘Serrano Criollo de Morelos-334’

Summary C. annuum L. ‘Serrano Criollo de Morelos-334’ (SCM-334) is a well-known source of resistance against pepper diseases, including Potato Virus Y (PVY). In this work, inheritance studies involving ‘SCM-334’ and related to PVY resistance were described. For this purpose, ‘SCM-334’ derived lines were used, and plant material from the cross between ‘SCM-334’ and ‘Yolo Wonder’ (YW) was employed as well. Five PVY isolates were used for the inoculations. The first resistance described is a monogenic and recessive gene, controlling a specific-isolate resistance, and provisionally named as pvr1 ⁴. The second one is related to the inheritance of systemic necrotic symptoms after PVY inoculation. In this case a codominant gene is proposed and expressed only when the Pvr4 gene is not present.     

Nutritional strategies for heifers under grazing system: productive and nutritional performance,metabolic profile and ovarian activity

The objective of this study was to evaluate the effects of nutritional strategies on productive and nutritional performance, metabolic profile, and ovarian activity in heifers under grazing in the tropics in Brazil. Forty Nellore heifers averaging 8.5?±?0.06 months and 248.6?±?3.3 kg body weight (BW) were distributed in a completely randomized 2?×?2 factorial design with four treatments and ten replicates. The evaluated strategies consisted of different amounts of energetic-protein supplement: (1) 4 g/kg of BW of supplement in the pre-weaning and post-weaning; (2) 4 g/kg of BW of supplement pre-weaning and 6 g/kg in the post-weaning; (3) 6 g/kg of BW of supplement in the pre-weaning and 4 g/kg of BW in the post-weaning and; (4) 6 g/kg of BW of supplement in the pre-weaning and post-weaning. Crude protein (CP) and organic matter (OM) intake were increased (P?<?0.05) by increasing the amounts of supplement in the post-weaning. Additionally, increasing supplement amounts in the post-weaning increased the digestibility of OM and CP (P?<?0.05). Means insulin and glucose concentrations were greater (P?<?0.05) for heifers that received higher amounts of supplement in the post-weaning. Average daily gain and fat thickness in the rump were increased (P?<?0.05) by increasing supplement amounts in the post-weaning. Amounts of supplement did not influence the body growth of heifers. However, follicular number, diameter, and progesterone concentration were greater (P?<?0.05) for heifers that received higher amounts of supplement in the post-weaning. In summary, increasing supplement amounts in the post-weaning improve the performance, energy and metabolic status, and ovarian activity in beef heifers under grazing in the tropics. Due to higher intake of supplement, the heifers receiving 6 g/kg of BW post-weaning had greater responses, independently of the supplement amount received pre-weaning.

     

Prenatal histomorphological development of the reticulum in fallow deer (Dama dama)

The histomorphological changes occurring in the Dama dama reticulum during prenatal development have been investigated. Twenty‐five Dama dama embryos were used, from the first stages of prenatal life until birth. Differentiation of the reticulum was observed at 23% gestation. By 25% gestation the reticular wall comprised three layers: an internal epithelial layer, a middle layer of pluripotential blastemic tissue and an external layer or serosa. Primary reticular crests were visible at 38% gestation. Secondary reticular crests were observed at 61% gestation. Neuroendocrine cells were detected by synaptophysin (SYP) at 35% gestation, in the lamina propria‐submucosa, tunica muscularis, and serosa. Epithelial Cytokeratin‐18 (CK‐18) cells were observed at 35% gestation extended throughout the epithelial layers. The glial cells (vimentin –VIM‐ and glial fibrillary acidic protein‐GFAP‐markers) were discerned at 25% and 43% gestation, respectively, in myenteric and submucosal plexuses, lamina propria, muscularis mucosae, tunica muscularis, and perivascular connective tissue. The neuropeptide Y (NPY) and vasoactive intestinal polypeptide (VIP) markers were immunodetected at 75% and 80 gestation, respectively, in the lamina propria‐submucosa, muscularis mucosae, tunica muscularis, serosa, and myenteric plexuses. The prenatal development of the fallow deer reticular mucosa evidenced a considerable precocity similar to that previously reported in goat and red deer.     

Mycoflora and occurrence of aflatoxin B(1) and fumonisin B(1) during storage of Brazilian sorghum

The present study is a 1-year follow up of the mycoflora of 140 samples of Brazilian freshly harvested (10) and stored (130) sorghum, the levels of aflatoxin and fumonisin contamination detected in the grains, and the prevailing abiotic factors (grain moisture content, water activity, temperature, relative humidity, and mean rainfall) at the time of sampling. The results show a predominance of the genera Phoma (57.1%), Aspergillus (42.7%), Fusarium (25.0%), and Rhizopus (21.4%) and the presence of nine other filamentous fungi. Fusarium, Aspergillus, and Penicillium, the three most important genera in terms of toxicity, presented numbers of colony forming units per gram of sorghum (CFU/g) that varied from 1 x 10(3) to 36 x 10(3), from 1 x 10(3) to 295 x 10(3), and from 1 x 10(3) to 20 x 10(3) CFU/g, respectively. The species most frequently found were Aspergillus flavus and Fusarium moniliforme. Of the total samples analyzed, 12.8% were contaminated with aflatoxin B(1) (concentration mean = 7-33 microg/kg) and 74.2% with fumonisin B(1) (concentration mean = 0.11-0.15 microg/g). This paper is the first report of the natural occurrence of aflatoxins and fumonisins in sorghum grain from Brazil.     

Fragmentation patterns and implications for biodiversity conservation in three biosphere reserves and surrounding regional environments, northeastern Mexico

Patterns of fragmentation in current distributions of 35 species of birds and 19 species of mammals that are considered endangered, threatened, or with restricted distributions were modeled in relation to 3 biosphere reserves (El Abra-Tanchipa, El Cielo, Sierra Gorda; ‘BRs’) and 13 areas identified as priorities for conservation in northeastern Mexico (PAC-Priority Areas for Conservation). Core area percentage of landscape (CPLAND) and aggregation index (AI) were used to summarize fragmentation trends in species’ geographic distributions, modeled using ecological niche modeling techniques. Overall (median) CPLAND and AI revealed: (a) for birds, El Abra-Tanchipa BR and neighboring areas exhibited the lowest fragmentation (high CPLAND and high AI), whereas Sierra Gorda BR was the most fragmented; (b) for mammals, El Abra-Tanchipa and El Cielo BRs exhibited lowest overall fragmentation, while Sierra Gorda BR was the most fragmented. Although there were areas (i.e., El Abra-Tanchipa BR and Parras de la Fuente PAC) with higher combination of CPLAND and AI values, El Cielo BR stands out because of its high CPLAND and AI values along with the highest species richness.