SEX-RATIO MANIPULATION IN COLOR-BANDED POPULATIONS OF ZEBRA FINCHES

Significant correlations were found between attractiveness of leg-band color (determined by preference tests [Burley et al., 1982]) and sex ratio of offspring in two long-term breeding experiments involving zebra finches. In both experiments, birds with attractive band colors produced more same-sex offspring, while birds with unattractive band colors produced more opposite-sex offspring. The results of these experiments are consistent with those of a previous experiment (Burley, 1981). To explain the earlier results, I hypothesized that parents adjust their allocation to sons and daughters to produce offspring they “expect” to be most attractive. The purpose of such sex-ratio manipulation is to enhance fitness by the production of offspring with superior mate-getting opportunities. Two alternative hypotheses are presented here. One is that sex ratios change with parental age and/or experience. Evidence does not support this hypothesis. There were no temporal trends in sex ratio independent of band color. A second possibility is that sex ratios reflect differential parental ability to rear sons and daughters. This hypothesis cannot be conclusively tested on the basis of present evidence, but available evidence does not support it. Within color classes, weights of sons and daughters did not differ. Evidence indicates that parents effect secondary sex-ratio manipulation through the selective rejection of young, usually within six days of hatching. There is no evidence of manipulation prior to egg-laying. The costs associated with brood reduction probably set limits on the extent to which secondary manipulation can be profitably employed.     

Cloning of the Human Monocarboxylate Transporter MCT3 Gene: Localization to Chromosome 22q12.3–q13.2

Lactate transport across cell membranes is mediated by a family of proton-coupled monocarboxylate transporters (MCTs). The retinal pigment epithelium (RPE) expresses a unique member of this family, MCT3. A portion of the human MCT3 gene was cloned by polymerase chain reaction using primers designed from rat RPE MCT3 cDNA sequence. The human genomic sequence was used to design primers to clone human MCT3 cDNA and to identify a bacterial artificial chromosome clone containing the human MCT3 gene. The human MCT3 cDNA contained a 1512-nucleotide open reading frame with a deduced amino sequence 85% identical to rat MCT3. Comparison of the cDNA and genomic sequences revealed that the MCT3 gene was composed of five exons distributed over 5 kb of DNA. The exon–intron borders were conserved between the human and the chicken MCT3 genes. Using radiation hybrid mapping, the MCT3 gene was mapped to chromosome 22 between markers WI11639 and SGC30687. A search of chromosome 22 in the Sanger Centre database confirmed the location of the human MCT3 gene at 22q12.3–q13.2.     

Phenylalkyl ketones as potent reversible inhibitors of interleukin-1β converting enzyme

Phenylalkyl ketones are potent reversible inhibitors of interleukin-1β converting enzyme (ICE). The extended alkyl chain ketones AcTyrValAlaAspCO(CH₂)_nPh display increased potency over the simple aryl ketone. In particular, the tetrapeptide AcTyrValAlaAspCOPh has a K_i of 10μM while AcTyrValAlaAspCO(CH₂)₅Ph has a K_i of 18.5nM.     

Canadians’ Perceptions of Food,Diet, and Health – A National Survey

Background

Poor nutrition is harmful to one’s health as it can lead to overweight and obesity and a number of chronic diseases. Understanding consumer perceptions toward diet and nutrition is critical to advancing nutrition-related population health interventions to address such issues. The purpose of this paper was to examine Canadians’ perceived health and diet status, compared to their actual health status, and general concern about their own diet and beliefs about health. Also analyzed were some of the perceived barriers to eating “healthy” foods, with a focus on the availability of “healthy” processed foods.

Methods

Two surveys were administered online to a group of Canadian panelists from all ten provinces during May 2010 to January 2011. Thirty thousand were invited; 6,665 completed the baseline survey and 5,494 completed the second survey. Panelists were selected to be nationally representative of the Canadian adult population by age, sex, province and education level, according to 2006 census data.

Results

Approximately one third of Canadians perceived their health or diet to be very good while very few Canadians perceived their health or diet to be very poor. While the majority of Canadians believed food and nutrition to be very important for improving one’s health, fewer Canadians were concerned about their own diets. The majority of Canadians reported difficulty finding “healthy” processed foods (low in salt and sugar and with sufficient vitamins and minerals). Many also reported difficulty finding healthy foods that are affordable.

Conclusion

Although consumers believe that nutrition is one of the most important factors for maintaining health, there are still a number of attitudinal and perceived environmental barriers to healthy eating.     

Identification of the synaptic vesicle glycoprotein 2 receptor binding site in botulinum neurotoxin A

Botulinum neurotoxins (BoNTs) inhibit neurotransmitter release by hydrolysing SNARE proteins. The most important serotype BoNT/A employs the synaptic vesicle glycoprotein 2 (SV2) isoforms A-C as neuronal receptors. Here, we identified their binding site by blocking SV2 interaction using monoclonal antibodies with characterised epitopes within the cell binding domain (H_C). The site is located on the backside of the conserved ganglioside binding pocket at the interface of the H_CC and H_CN subdomains. The dimension of the binding pocket was characterised in detail by site directed mutagenesis allowing the development of potent inhibitors as well as modifying receptor binding properties.     

Honey Bee Hemocyte Profiling by Flow Cytometry

Multiple stress factors in honey bees are causing loss of bee colonies worldwide. Several infectious agents of bees are believed to contribute to this problem. The mechanisms of honey bee immunity are not completely understood, in part due to limited information about the types and abundances of hemocytes that help bees resist disease. Our study utilized flow cytometry and microscopy to examine populations of hemolymph particulates in honey bees. We found bee hemolymph includes permeabilized cells, plasmatocytes, and acellular objects that resemble microparticles, listed in order of increasing abundance. The permeabilized cells and plasmatocytes showed unexpected differences with respect to properties of the plasma membrane and labeling with annexin V. Both permeabilized cells and plasmatocytes failed to show measurable mitochondrial membrane potential by flow cytometry using the JC-1 probe. Our results suggest hemolymph particulate populations are dynamic, revealing significant differences when comparing individual hive members, and when comparing colonies exposed to diverse conditions. Shifts in hemocyte populations in bees likely represent changing conditions or metabolic differences of colony members. A better understanding of hemocyte profiles may provide insight into physiological responses of honey bees to stress factors, some of which may be related to colony failure.     

Genome-Wide Expression Analysis in Fibroblast Cell Lines from Probands with Pallister Killian Syndrome

Pallister Killian syndrome (OMIM: # 601803) is a rare multisystem disorder typically caused by tissue limited mosaic tetrasomy of chromosome 12p (isochromosome 12p). The clinical manifestations of Pallister Killian syndrome are variable with the most common findings including craniofacial dysmorphia, hypotonia, cognitive impairment, hearing loss, skin pigmentary differences and epilepsy. Isochromosome 12p is identified primarily in skin fibroblast cultures and in chorionic villus and amniotic fluid cell samples and may be identified in blood lymphocytes during the neonatal and early childhood period. We performed genomic expression profiling correlated with interphase fluorescent in situ hybridization and single nucleotide polymorphism array quantification of degree of mosaicism in fibroblasts from 17 Caucasian probands with Pallister Killian syndrome and 9 healthy age, gender and ethnicity matched controls. We identified a characteristic profile of 354 (180 up- and 174 down-regulated) differentially expressed genes in Pallister Killian syndrome probands and supportive evidence for a Pallister Killian syndrome critical region on 12p13.31. The differentially expressed genes were enriched for developmentally important genes such as homeobox genes. Among the differentially expressed genes, we identified several genes whose misexpression may be associated with the clinical phenotype of Pallister Killian syndrome such as downregulation of ZFPM2, GATA6 and SOX9, and overexpression of IGFBP2.     

Suberized bundle sheaths in grasses (Poaceae) of different photosynthetic types. II. Apoplastic permeability

Summary The relative hydraulic conductivities of major and minor longitudinal veins, and the apoplastic permeability of the bundle sheaths surrounding all longitudinal and transverse veins were investigated in representatives of the C₃, C₄/NAD-ME, C₄/NAD-ME/PCK intermediate, C₄/PCK and C₄/NADP-ME photosynthetic types. Using the Hagen-Poiseuille equation and measurements of tracheary element diameters, the number of elements in each vein type and the numbers of each vein type, we calculated that 87–99% of the water flow in a longitudinal direction would be expected to occur in the major veins. The permeability of the mestome sheaths and parenchymatous bundle sheaths surrounding the veins was tested using the negatively-charged, fluorescent dye, trisodium 3-hydroxy-5,8,10-pyrenetrisulfonate (PTS). This dye proved nontoxic to plant tissue at a concentration of 0.5%, according to a deplasmolysis test with onion epidermal strips. The PTS concentration achieved in the tested grass leaves was about 0.035%, well below the toxic limit. When a solution of PTS was fed to the leaves by means of a basal cut, the dye moved into the veins of all orders. From there, it moved outward into the surrounding tissues, indicating that the sheaths surrounding the veins of all orders in all species tested were permeable. Therefore, contrary to previous predictions based on structural observations and some tracer studies, bundle sheaths with suberized cell walls do not function as endodermal layers.     

Anatomy of normal and hyperhydric leaves and shoots of in vitro grown Simmondsia chinesis (link) schn

Summary The anatomy of normal and hyperhydric in vitro shoots and leaves from micropropagated simmondsia chinensis (Link.) Schn. (jojoba) was compared with that of seedlings (control plants). In vitro normal plantlets displayed good development and survived during the acclimatization stage. In vitro hyperhydric plantlets presented numerous anatomical defects, such as hypertrophy of the mesophyll and of the stem cortex, malformed non-functional stomata, epidermal discontinuity, and xylem hypolignification; they did not survice acclimatization. The study of the anatomical features of in vitro jojoba shoots and leaves allowed determination of the structural condition of the plantlets and prediction of which plantlet would survive the critical acclimatization stage.