Microspectrophotometry of photoreceptor organelles from eyes of the prawn Palaemonetes

Microspectrophotometric measurements of individual dark-adapted rhabdoms of the prawn Palaemonetes vulgaris reveal the presence of two light-sensitive pigments. A pigment with maximum absorbancy at 555 nanometers is converted by light to a long-lived intermediate with wavelength of maximum absorbancy at 496 nanometers. A second pigment with wavelength of maximum absorbancy at 496 nanometers bleaches in the light, seemingly without forming detectable products at wavelengths longer than 375 nanometers. Both pigments occur in each layer of microvilli.     

Demonstration of Sugar Residues in the Ultimobranchial Tubule and Thyroid C-Cells of the Rat using Peroxidase Labelled Lectins

The distribution of various sugars, that contribute to the composition of the carbohydrate components of the glycoprotein in the ultimobranchial tubule and the thyroid C-cells has been studied, using eight peroxidase-labelled lectins (Dolichos biblorus, Glycine max, Bauhinia purpurea, Helix pomatia, Arachis hipogaea, Ulex europaeus I, Limax flavus and Sophora japonica). The results obtained seem to show that there are receptors for Dolichos biflorus, Glycine max, Bauhinia purpurea, Helix pomatia, Arachis hipogaea, Ulex europaeus I and Limax flavus in the ultimobranchial tubule, suggesting the existence of N-acetylgalactosamine, galactose, L-fucose and sialic acid. However, the C-cells show only a positive reaction with Ulex europaeus I indicating the existence of fucosyl residues in those cells. All these findings support the contention that the ultimobranchial body might contribute decisively not only to the formation of C-cells but also, partially, to the constitution of certain follicular cells.     

Repeated handling of pigs during rearing. II. Effect of reactivity to humans on aggression during mixing and on meat quality

The present study was designed to determine whether reactivity toward humans can be used to predict a pig's reactivity to the slaughter procedure as measured by postmortem muscle metabolism. Forty-two pigs were group-reared in six pens with straw-bedding. Pigs received regular positive (HI) or mildly negative (RC) handling training in a separate pen for 40 d before slaughter. Control pigs remained in their home pens throughout rearing. Pigs were slaughtered at a commercial packing plant, and half of each treatment group (HI, RC, or controls) was accompanied by the handler throughout mixing and transportation, as well as a portion of the lairage time and introduction to the holding pens situated before the slaughter room, whereas the other half was not accompanied by the handler. Muscle pH and temperature, objective color (L*, a*, and b* values), and drip loss were measured on the LM, biceps femoris, semimembranosus, and adductor femoris. Prior handling experience did not in itself influence ultimate meat quality (P > 0.37); however, the presence of the negative handler (RC pigs) at slaughter accelerated (P < 0.06) preslaughter glycogen breakdown in the LM. Fighting behavior during mixing explained between 13 and 32% of the variability of lightness (L* values) of the LM, biceps femoris, and semimembranosus. Visual contact with the handler at the start of the handling training and number of fights initiated explained between 31 and 42% of the variability in ultimate muscle pH. Latency to approaching the handler during human exposure tests explained 20% of the variability in initial muscle temperature of two muscles. Fighting behavior during mixing could be partly predicted from fighting during a food competition test conducted at the start of the rearing period. Results indicate that reactivity to humans and the tendency to fight determined, in part, meat quality in pigs of similar genetic and rearing backgrounds. These behavioral characteristics were, to some extent, determined early in life. Handling experience modified behavior toward the handler but correlations between behavioral characteristics and meat quality were not influenced by prior handling experience.     

Effects of quinoa hull meal on piglet performance and intestinal epithelial physiology

Saponin-containing feed additives have shown positive effects on pig performance. Quinoa hull has high saponin content and may be of interest as a feed additive. This study aimed to evaluate quinoa hull meal (QHM) as a feed additive in a pig diet. The effects of QHM were assessed for three dosages of South American (SA) origin (100, 300 and 500 mg/kg) and one dosage of Danish (DK) quinoa (300 mg/kg). In addition, the effect of dietary SA-QHM and SA-QHM-extract on jejunal epithelial physiology was studied ex vivo in Ussing chambers. The experiment included 400 piglets weaned at 28 ± 2 days of age and the experimental period was 4 weeks. Piglets were weighed initially and finally and feed intake registered. The ex vivo studies were performed with epithelium from 40 pigs receiving control or SA-QHM. Epithelium from each pig was placed into eight Ussing chambers, where four concentrations of SA-QHM-extract were added. Epithelial permeability, Na(+)-dependent glucose transport and serotonin (5-HT) and theophylline-induced secretion were measured. The results showed that QHM had no influence on piglet's growth (p = 0.41) or feed intake (p = 0.17). In spite of a large difference in saponin content between SA-QHM and DK-QHM (28.7% and 2.0% w/w respectively) the source did not affect pig performance. The ex vivo studies revealed no effect (p > 0.05) of adding QHM-extract into the medium. The permeability and glucose induced absorption were highest (p = 0.003 and p = 0.04 respectively) in epithelium from pigs that consumed 100 or 300 mg/kg SA-QHM. The secretory response to 5-HT was not affected (p = 0.59) by dietary treatments, but the theophylline-induced secretion decreased (p = 0.02) with increasing dietary SA-QHM. The changes in epithelial physiology measured ex vivo did not affect animal performance in vivo in this study.     

Fatty acid,amino acid,and trace mineral analyses of five weaning foods from Jos,Nigeria

Five plant-based weaning foods (WF) (Dietrend, Jot-M, Soy, Ang and Vic-T) locallyprepared in Jos, Nigeria were analyzed by gas-liquid chromatography,reverse-phase high performance liquid chromatography, and atomicemission spectrometry with inductively coupled plasma to determine theirfatty acid (FA), amino acid, and trace mineral contents, respectively.Results of these direct analyses were compared to expected values derivedfrom food composition tables prepared by the United States Department of Agriculture (USDA). Additionally, results were compared against recommendednutrient values, using breast milk as the standard for FA content andrecommended dietary allowances (RDA) for amino acid and mineral contents.The overall nutritional value of the five WF varied considerably and thequantities of particular nutrients determined by direct analysis differedmarkedly from those estimated using USDA food tables. Comparison of WFfatty acid composition relative to the RDA recommendations and a humanmilk standard revealed a much higher proportion of both linoleic (35–55wt%) and -linolenic acids (1%–7 wt%) relative to human milklipids (11%–12% and 0.8%–0.9% wt, respectively); however, the WFwere devoid of arachidonic acid and docosahexaenoic acid. Soy containedthe highest amounts of linoleic acid (59.7 mg/g) and -linolenicacid (7.46 mg/g) compared to the other four WF (10.2–41.0 and 0.35–3.18 mg/g, respectively). The linoleic acid/-linolenic acid ratio was within the recommended range (5:1 to 10:1) in only Jot-M (10:1)and Soy (8:1). Dietrend, Vic-T and Ang, containedlinoleic/-linolenic ratios of 12:1, 29:1, and 82:1, respectively.The Soy weaning food would provide the most protein (24.3 g/day), basedon an estimated daily intake of 65 g of weaning food by a normalsix-month-old infant, compared to Jot-M (11.9 g/day), Dietrend (11.7g/day), Ang (8.07 g/day) and Vic-T (7.26 g/day). The protein RDA forchildren up to 1 year of age is 13–14 g/day. Comparison of the mineralcontents of the WF to the RDAs for various minerals indicated that all fivewould provide suboptimal amounts of calcium (16 to 250 mg/day) andzinc (1.42 to 3.56 mg/day) compared to respective RDAs of400 mg/day and 5 mg/day.These data show that the Soy weaning food is an excellent source of linoleicacid and -linolenic acid, as well as being a good source of highquality protein. Jot-M and Dietrend provide useful amounts of the essentialFA; however, it is advisable to reevaluate the composition of Ang andVic-T to find ways to improve the linoleic/-linolenic ratio of eachand increase their total protein content. These results document theshortcomings of using published food composition tables based on foods inAmerica when devising weaning foods based on ingredients in another partof the world.     

Role of nonimmune IgG bound to PfEMP1 in placental malaria

Infections with Plasmodium falciparum during pregnancy lead to the accumulation of parasitized red blood cells (infected erythrocytes, IEs) in the placenta. IEs of P. falciparum isolates that infect the human placenta were found to bind immunoglobulin G (IgG). A strain of P. falciparum cloned for IgG binding adhered massively to placental syncytiotrophoblasts in a pattern similar to that of natural infections. Adherence was inhibited by IgG-binding proteins, but not by glycosaminoglycans or enzymatic digestion of chondroitin sulfate A or hyaluronic acid. Normal, nonimmune IgG that is bound to a duffy binding-like domain beta of the P. falciparum erythrocyte membrane protein 1 (PfEMP1) might at the IE surface act as a bridge to neonatal Fc receptors of the placenta.     

PrP antibodies do not trigger mouse hippocampal neuron apoptosis

Intraperitoneal administration of ICSM18 and 35, monoclonal antibodies against prion protein (PrP), has been shown to significantly delay the onset of prion disease in mice, and humanized versions are candidate therapeutics for prion and Alzheimer's diseases. However, a previous report of severe and widespread apoptosis after intracerebral injection of anti-PrP monoclonal antibodies raised concerns about such therapy and led to an influential model of prion neurotoxicity via cross-linking of cell surface PrP by disease-related PrP aggregates. In extensive studies including ICSM18 and 35, fully humanized ICSM18, and the previously reported proapoptotic antibodies, we found no evidence of apoptosis, thereby questioning this model of prion neurotoxicity.     

Differential tissue accumulation of arsenic and heavy metals from diets in three edible fish species

Three different commercial fish species Odontesthes bonariensis, Rhamdia quelen and Oreochromis niloticus and fish feed were collected from four aquaculture farms. Heavy metal (Cd, Cr, Cu, Fe, Mn, Pb and Zn) and arsenic concentration were determined by inductively coupled plasma–optical emission spectrometry (ICP‐OES) in muscle, liver, gonad, skin, scale and fat from fish and in feed diets. Arsenic concentration was found in different tissues differing between species and within O. bonariensis. Cd was differentially accumulated in liver in O. bonariensis and R. quelen; however, in O. niloticus Cd was found in muscle and scales. Higher concentrations of Cr were determined in skin and scales of O. bonariensis and O. niloticus. Cu, Fe, Mn and Zn were found in all tissues being Cu and Fe concentrations higher in liver. Mn was differentially accumulated in O. bonariensis scales, however in R. quelen no significant differences were found and in O. niloticus liver was the main accumulation tissue. Zn concentration was higher in gonad, skin and liver from R. quelen and O. bonariensis, and in O. niloticus the highest concentration was found in scales. All the results were below the international limits for food safety except for the concentration of Cd in muscle and scales of O. niloticus.     

Methacarn preserves mucus integrity and improves visualization of amoebae in gills of Atlantic salmon (Salmo salar L.)

Two aqueous fixation methods (modified Davidson's solution and modified Davidson's solution with 2% (w/v) Alcian blue) were compared against two non‐aqueous fixation methods (methacarn solution and methacarn solution with 2% (w/v) Alcian blue) along with the standard buffered formalin fixation method to (a) improve preservation of the mucous coat on Atlantic salmon, Salmo salar L., gills and (b) to examine the interaction between the amoebae and mucus on the gill during an infection with amoebic gill disease. Aqueous fixatives demonstrated excellent cytological preservation but failed to deliver the preservation of the mucus when compared to the non‐aqueous‐based fixatives; qualitative and semi‐quantitative analysis revealed a greater preservation of the gill mucus using the non‐aqueous methacarn solution. A combination of this fixation method and an Alcian blue/Periodic acid–Schiff staining was tested in gills of Atlantic salmon infected with amoebic gill disease; lectin labelling was also used to confirm the mucus preservation in the methacarn‐fixed tissue. Amoebae were observed closely associated with the mucus demonstrating that the techniques employed for preservation of the mucous coat can indeed avoid the loss of potential mucus‐embedded parasites, thus providing a better understanding of the relationship between the mucus and parasite.