Sexual Maturation in the Bull

In this review, we describe the process of sexual maturation in the bull calf. The testes of the bull grow relatively slowly until approximately 25 weeks of age and then a rapid phase of growth occurs until puberty, at 37–50 weeks of age. During the early postnatal phase of slower growth of the testis pre-spermatogonia and some spermatogonia are established, adult Leydig cells appear and undifferentiated Sertoli cells are produced. The rapid testicular growth, after 25 weeks of age, consists of marked increases in the diameter and length of the seminiferous tubules, dramatic proliferation and differentiation of germ cells, with mature spermatozoa occurring between 32 and 40 weeks of age. The adult Leydig cell population is largely in place by 30 weeks of age and that of Sertoli cells by 30–40 weeks of age. Serum concentrations of LH increase from 4 to 5 weeks of age, to an early postnatal peak at 12–16 weeks of age, followed by a decline to 25 weeks of age. Serum FSH concentrations are high postnatally, declining to approximately 25 weeks of age. Serum testosterone concentrations increase during the phase of rapid testicular growth. Hypothalamic opioidergic inhibition may abate transiently to allow the early postnatal increase in LH secretion, while testicular androgenic negative feedback probably contributes to the decline in gonadotropin secretion to 25 weeks of age. Several lines of study have led us to suggest that early postnatal gonadotropin secretion is pivotal in initiating the process of sexual maturation in the bull calf.     

Evaluation of alternatives to antibiotics using an Escherichia coli K88+ model of piglet diarrhea: effects on gut microbial ecology

Enterotoxigenic Escherichia coli is a major problem in the swine industry and results in scouring, increased mortality, and poor performance in the period immediately postweaning. The traditional way to control this problem is to include subtherapeutic antibiotics in the feed, but this is no longer acceptable to consumers; thus, alternatives to antibiotics are needed. One of the supplements that has been effective in reducing scouring in the absence of antibiotics is animal blood products produced from the rendering process. This is also becoming a problem because of concerns regarding the transfer of transmissible spongiform encephalopathies to humans from animals. In this research, we investigated the effects of spray-dried porcine plasma (SDPP), a Bacillus subtilis direct-fed microbial (DFM), a blend of organic acids, and sweeteners on E. coli-induced scouring. A total of 108 pigs of approximately 17 d of age were assigned to 6 treatments, with 3 pigs per pen, in 2 blocks, with each block having 3 replicates. The 2 blocks were initiated approximately 2 mo apart, because a sufficient number of pigs were not available that met our inclusion criteria in the first block. Diet 1 was a negative control containing no antibiotics (NC). Diet 2 was the positive control and included the same ingredient composition as NC except that antibiotics (110 mg/kg of chlortetracycline, 110 mg/kg of sulfamethazine, and 55 mg/kg of penicillin) were added (PC). Diet 3 was equal to the NC, but with a B. subtilis probiotic (DFM). Diet 4 was the NC to which SDPP was added. Diet 5 was the NC plus a combination of SDPP and DFM (SDPP + DFM). Diet 6 was the NC plus a combination of supplements, including SDPP and a blend of organic acids, DFM, and a sweetener (Blend). At 24 d of age, the pigs were experimentally infected with 6.3 x 10(9) cfu/mL of E. coli K88. All pigs were euthanized 7 d after infection and tissues were obtained for analysis. There were no significant differences among treatments for ADG, ADFI, G:F, plasma urea nitrogen, alpha-acid glycoprotein, tumor necrosis factor-alpha, intestinal ammonia, pH, or VFA. However, the PC and DFM treatments showed decreased (P < 0.05) scours at 24 h postinfection compared with the NC, SDPP, and SDPP + DFM diets. Mortality in the NC treatment, which did not contain antibiotics, was greater (P < 0.05) than in the other treatments. Terminal restriction fragment length polymorphism analysis of the 16S rDNA genes of digesta showed a greater incidence (P < 0.05) of Bacteroidetes in the PC and DFM diets than in the NC diet. When SDPP and DFM were included in the diet, the incidence of Bacteroidetes was also greater than in the NC diet (P < 0.05).     

Histology-guided high-resolution AP-SMALDI mass spectrometry imaging of wheat-<Emphasis Type="Italic">Fusarium graminearum</Emphasis> interaction at the root–shoot junction

Background

Fungal pathogens like Fusarium graminearum can cause severe yield losses and mycotoxin contamination of food and feed worldwide. We recently showed its ability to systemically colonize wheat via root infection. However, the molecular response of wheat to Fusarium root rot (FRR) infection and systemic spread is still unknown. As a molecular camera, mass spectrometry (MS) imaging combines label-free and multiplex metabolite profiling with histopathology.

Results

Atmospheric-pressure (AP)-SMALDI-MS imaging was combined with optical microscopy to study wheat-F. graminearum interaction at the root–shoot junction, which is a crucial line of defense against a pathogen that can invade all distal plant parts. To scope the functional, temporal and local aspects of FRR disease spread, metabolic changes were simultaneous visualized in diseased and healthy stem bases of the resistant cultivar Florence-Aurore at 10, 14 and 21 days after root inoculation. Histological information was used to identify disease relevant tissues and to assist the interpretation of molecular images. Detected mycotoxin compounds secreted by F. graminearum showed a route of stem infection that was consistent with observations made by microscopy. The outer epidermis and vasculature of leaf sheath were, at different disease stages, identified as prominent sites of pathogen migration and wheat protection. Wheat metabolites mapped to these relatively small tissues indicated cell wall strengthening and antifungal activity as direct defenses as well as conservation in the wheat reactions to F. graminearum diseases that affect different plant organs.

Conclusions

AP-SMALDI-MS imaging at high spatial resolution is a versatile technique that can be applied to basic and applied aspects of agricultural research. Combining the technology with optical microscopy was found to be a powerful tool to gain in-depth information on almost unknown crop disease. Moreover, the approach allowed studying metabolism at the host–pathogen interface. The results provide important hints to an understanding of the complex spatio-temporal organization of plant resistance. Defense-on-demand responses to pathogen ingress were found, which provide opportunities for future research towards an improved resistance that does not negatively impact yield development in the field by saving plant resources and, moreover, may control different Fusarium diseases.

     

The role estrogens play in sex differentiation and sex changes of fish

Using genetically controlled all-female and all-male tilapia (Oreochromis niloticus), the role steroid hormones play in the sex differentiation was analyzed histologically, ultrastructurally, immunohistichemically and experimenntally. The results strongly suggest that endogenous estrogen acts as an ovarian inducer, and that the lack of steroid hormone including androgen is important for testicular differentiation. Moreover, the roles of steroid hormones in protogynous sex change of three-spotted wrasse (Halichoeres trimaculatus) and saddleback wrasse (Tharassoma duperrey) were examined. The results strongly support the hypothesis that the endogenous estrogen plays an important role in protogynous sex change.     

Rare structural variants disrupt multiple genes in neurodevelopmental pathways in schizophrenia

Schizophrenia is a devastating neurodevelopmental disorder whose genetic influences remain elusive. We hypothesize that individually rare structural variants contribute to the illness. Microdeletions and microduplications >100 kilobases were identified by microarray comparative genomic hybridization of genomic DNA from 150 individuals with schizophrenia and 268 ancestry-matched controls. All variants were validated by high-resolution platforms. Novel deletions and duplications of genes were present in 5% of controls versus 15% of cases and 20% of young-onset cases, both highly significant differences. The association was independently replicated in patients with childhood-onset schizophrenia as compared with their parents. Mutations in cases disrupted genes disproportionately from signaling networks controlling neurodevelopment, including neuregulin and glutamate pathways. These results suggest that multiple, individually rare mutations altering genes in neurodevelopmental pathways contribute to schizophrenia.     

Bitterness and Toxicity in Wild Yam (<Emphasis Type="Italic">Dioscorea</Emphasis> spp.) Tubers of Nepal

Wild yams make a significant contribution to diets of tribal people in Nepal. However, these wild tubers are unpalatable, taste bitter, produce inflammation and show occasional toxicity. Four wild yam species, which are eaten after primary treatment by Nepali aborigines, were analyzed for bitter and toxic principles. Bitter components were identified as furanoid norditerpenes (diosbulbins A and B). Diosbulbins A and B were found in the range of 0.023–0.046 and 0.151–0.442 g kg⁻¹, respectively. Results demonstrated that diosbulbin B, with an average value of 0.314 g kg⁻¹, was the principal bitter compound as compared to diosbulbin A (0.037 g kg⁻¹). The toxic alkaloid, dioscorine and histamine (an allergen) were not detected in these tubers, whereas cyanogens (as HCN equivalent) content were found ranging from 3.2 to 6.0 ppm. Our results revealed that Nepali wild yam tubers are not toxic varieties, as they do not contain either toxic dioscorine or histamine and cyanogens contents were satisfactorily below the safety limits. The inflammation and occasional toxicity observed could possibly be due to the presence of high level of oxalate in these tubers. Domestic cooking methods were found to be very efficient in removing bitterness, thus making the bitter yams palatable.     

Formation of dityrosine cross-links during breadmaking

To establish its significance during commercial breadmaking, dityrosine formation was quantified in flours and doughs of six commercial wheat types at various stages of the Chorleywood Bread Process. Dityrosine was formed mainly during mixing and baking, at the levels of nmol/g dry weight. Good breadmaking flours tended to exhibit a higher dityrosine content in the final bread than low quality ones, but no relationship was found for dityrosine as a proportion of flour protein content, indicating that the latter was still a dominant factor in the analysis. There was no correlation between gluten yield of the six wheat types and their typical dityrosine concentrations, suggesting that dityrosine cross-links were not a determinant factor for gluten formation. Ascorbic acid was found to inhibit dityrosine formation during mixing and proving, and it has no significant effect on dityrosine in the final bread. Hydrogen peroxide promoted dityrosine formation, which suggests that a radical mechanism involving endogenous peroxidases might be responsible for dityrosine formation during breadmaking.     

Effects of supplemental dietary vitamin C on quality of semen from Nile tilapia (Oreochromis niloticus) breeders

The objective of this study was to evaluate the effects of vitamin C on growth and quality of semen from Oreochromis niloticus breeders. One hundred and sixty males were fed with different levels of vitamin C (0, 261, 599 and 942 mg/kg diet). The higher weight values were recorded for 599 (166 g) and 942 (175 g) mg of vitamin C/kg diet. Sperm motility, vigour and concentration were higher with 599 and 942 mg of vitamin C/kg diet. The semen volume, gonadosomatic index and plasma protein data from the last week showed a direct relationship with increasing levels of vitamin C. No changes were observed in the hepatosomatic index and blood glucose. The haematocrit and erythrocyte showed higher values estimated by equations derived at 850 and 638 mg vitamin C/kg diet, respectively. The leucocytes were inversely proportional to the increasing levels of vitamin C. After 100 days of feeding, animals fed the diet containing 942 mg vitamin C/kg diet had higher sperm motility, linearity, curvilinear velocity, straight line velocity and average path velocity (p < .05). Higher values of beat cross‐frequency were observed in broodfish fed diets containing 942 and 599 mg vitamin C/kg. The different vitamin C levels did not cause differences in straightness, lateral head displacement and sperm morphology. For Nile tilapia males on intensive rearing and handling conditions, vitamin C levels between 599 and 942 mg/kg may be used for a better performance and quality of semen.