An investigation of the use of recovered vegetable oil for the preparation of starch thermoplastics

The main components (90%) in recovered vegetable oil (RVO) are esters of higher carboxylic acids and glycerol (triglycerides) which consist of three fatty acids: oleic (C18:1, Z), palmitic (C16:0) and linoleic (C18:2, Z) in the ratio 2.8:1.4:1. RVO may provide a low cost new supply of unsaturated fatty acid chlorides. Modification of potato starch using the mixture of fatty acid chlorides derived from RVO and using acid chlorides of the two major pure component acids has been performed. Films were prepared from the starch esters and mechanical properties tested. Commercially available potato starch, modified to DS-value 1.5 with RVO-derived acyl chlorides, was thermoplastic with a maximum tensile strength of 1.4 MPa and an elongation at break of 54%.     

In-vivo studies of mammary development in the goat using magnetic resonance imaging (MRI)

Mammary development and regression were measured in goats in vivo using magnetic resonance imaging (MRI). Measurements were made during the first and second cycles of pregnancy, lactation and involution. In primiparous goats, and exponential pattern of growth was evident during gestation and for the first 2 weeks of lactation. Parenchyma volume correlated significantly with milk yield across goats during early lactation, and across stage of lactation within goats. Milking was discontinued in Week 26 of the first lactation. Involution was characterized by an initial accumulation of fluid (over 2 days) followed by reabsorption; parenchyma volume did not decrease significantly until the 3rd week of involution, which was also the time at which these goats were mated to start their second gestation. Their udders still contained significant quantities of fluid (40-60% of the gross volume), but parenchyma volume was also greater (by 4.7-fold) than in goats beginning their first gestation. By Week 15 of gestation there was no longer a parity difference in parenchyma; the udders of first-gestation goats had grown significantly, but those of second-gestation goats had not. Conversely, between gestation Week 15 and lactation Week 2 mammary growth was significantly more rapid in the second cycle, such that the udder was larger at the start of the second lactation.     

Long-term physical impairment and functional outcomes after complex facial fractures

To develop an understanding of the expected functional outcomes after facial trauma, a retrospective cohort study of patients with complex facial fractures was conducted. A cohort of adults aged 18 to 55 years who were admitted to the R. Adams Cowley Shock Trauma Center between July of 1986 and July of 1994 for treatment of a Le Fort midface fracture (resulting from blunt force) was retrospectively identified.Outcomes of interest included measures of general health status and psychosocial well being in addition to self-reported somatic symptoms. General health status was ascertained using the Medical Outcomes Study 36-Item Short Form Health Survey (SF-36). The Body Satisfaction Scale was used to define patient concerns about altered body image and shape. To determine whether complex maxillofacial trauma and facial fractures contributed to altered social interactions, the Social Avoidance and Distress scale was used. In addition, information about a patient, his or her injury, and its treatment were ascertained from the medical records.Using the methods described above, 265 patients with Le Fort fractures were identified. These individuals were matched to a similar group of 242 general injury patients. A total of 190 of the Le Fort patients (72 percent of those eligible for the study) and 144 (60 percent) general injury patients were successfully located, and long-term interview data were acquired.Le Fort fracture patients as a group had similar health status outcomes when compared with the group of general injury patients. However, when outcomes were examined by the complexity of the Le Fort fracture, the authors found that study subjects with severe, comminuted Le Fort injuries (group D) had significantly lower SF-36 scores (worse outcomes) for the two dimensions related to role limitations: role limitations due to physical problems and role limitations due to emotional problems (p < 0.05). SF-36 scores for all other dimensions except physical function were also lower for comminuted versus less complex Le Fort fractures, although differences were not statistically significant.Specifically, there was a direct relationship between severity of facial injury and patients reporting work disability. Of group C and D Le Fort patients (severely comminuted fractures) only 55 and 58 percent, respectively, had returned to work at the time of follow-up interview. These figures are significantly lower than the back-to-work percentage of patients with less severe facial injury (70 percent).When study participants were asked if they were experiencing specific somatic symptoms at the time of the interview that they had not experienced before the injury, a significantly larger percent of the Le Fort fracture patients (compared with the general injury patients) responded in the affirmative. Differences between the Le Fort fracture and general injury groups were statistically significant (p < 0.05) for all 11 symptoms.The percentage of patients reporting complaints increased with increasing complexity of facial fracture in the areas of visual problems, alterations in smell, difficulty with mastication, difficulty with breathing, and epiphora, and these differences reached statistical significance.Patients sustaining comminuted Le Fort facial fractures report poorer health outcomes than patients with less severe facial injury and substantially worse outcomes than population norms. It is also this severely injured population that reports the greatest percentage of injury-related disability, preventing employment at long-term follow-up. The long-term goal of centralized tertiary trauma treatment centers must be to return the patient to a productive, active lifestyle.     

Application of Nile red, a fluorescent hydrophobic probe, for the detection of neutral lipid deposits in tissue sections: comparison with oil red O

Nile red is a phenoxazone dye that fluoresces intensely, and in varying color, in organic solvents and hydrophobic lipids. However, the fluorescence is fully quenched in water. The dye acts, therefore, as a fluorescent hydrophobic probe. We utilized this novel property of nile red to develop a sensitive fluorescent histochemical stain for tissue lipids. Nile red was prepared by boiling Nile blue A under reflux for 2 hr in 0.5% H2SO4, and extracting the product into xylene. For staining, the purified dye is dissolved in 75% glycerol (1-5 micrograms/ml) and applied to frozen tissue sections. Tissue lipids then fluoresce yellow-gold to red, depending on their relative hydrophobicity. Using sections of liver and aorta from a cholesterol-fed rabbit, we assessed the value of Nile red as a stain for neutral lipids by comparing the staining pattern obtained with that produced by oil red O, a commonly used dye for tissue cholesteryl esters and triacylglycerols. In the cholesterol fatty liver, Nile red staining was comparable to that of oil red O. In contrast, Nile red staining of rabbit aortic atheroma revealed ubiquitous lipid deposits not observed with oil red O staining. These latter results suggest that Nile red can detect neutral lipid deposits, presumably unesterified cholesterol, not usually seen with oil red O or other traditional fat stains.     

Divergence of duplicated genes in maize: evolution of contrasting targeting information for enzymes in the porphyrin pathway

The divergence of sequence and expression pattern of duplicated genes provides a means for genetic innovation to occur without sacrificing an essential function. The cpx1 and cpx2 genes of maize are a singular example of duplicated genes that have diverged by deletion and creation of protein targeting information. The cpx genes encode coproporphyrinogen III oxidase ('coprogen oxidase'), which catalyzes a step in the synthesis of chlorophyll and heme. In plants, this enzyme has been found exclusively in the plastids. The cpx1 and cpx2 genes encode almost identical, catalytically active enzymes with distinctive N-terminal peptide sequences. The cpx1 gene encodes the expected plastid transit peptide, but this region is deleted from the cpx2 gene. While the 5' regions of both messenger RNAs are highly similar, the cpx2 gene has an open-reading frame that could encode a new targeting signal. GFP fused with CPX1 localized to the plastids. In contrast, the GFP fusion with CPX2 did not target plastids and appeared to localize to mitochondria. Both cpx genes are expressed ubiquitously but, based on mutant phenotype, they seem to have discrete biological roles. Seedlings homozygous for a null mutation in the cpx1 gene completely lack chlorophyll and develop necrotic lesions in the light. However, the mutant seedlings and callus cultures will grow in tissue culture in the dark, implying that they retain a capacity to produce heme. We discuss models for the evolution of the cpx genes and possible roles of mitochondrion-localized coprogen oxidase activity in maize.     

Resource availability and plant diversity explain patterns of invasion of an exotic grass

Aims In this study, we examine two common invasion biology hypotheses—biotic resistance and fluctuating resource availability—to explain the patterns of invasion of an invasive grass, Microstegium vimineum.Methods We used 13-year-old deer exclosures in Great Smoky Mountains National Park, USA, to examine how chronic disturbance by deer browsing affects available resources, plant diversity, and invasion in an understory plant community. Using two replicate 1 m 2 plots in each deer browsed and unbrowsed area, we recorded each plant species present, the abundance per species, and the fractional percent cover of vegetation by the cover classes: herbaceous, woody, and graminoid. For each sample plot, we also estimated overstory canopy cover, soil moisture, total soil carbon and nitrogen, and soil pH as a measure of abiotic differences between plots.Important findings We found that plant community composition between chronically browsed and unbrowsed plots differed markedly. Plant diversity was 40% lower in browsed than in unbrowsed plots. At our sites, diversity explained 48% and woody plant cover 35% of the variation in M. vimineum abundance. In addition, we found 3.3 times less M. vimineum in the unbrowsed plots due to higher woody plant cover and plant diversity than in the browsed plots. A parsimonious explanation of these results indicate that disturbances such as herbivory may elicit multiple conditions, namely releasing available resources such as open space, light, and decreasing plant diversity, which may facilitate the proliferation of an invasive species. Finally, by testing two different hypotheses, this study addresses more recent calls to incorporate multiple hypotheses into research attempting to explain plant invasion.     

Transmission of MRSA between companion animals and infected human patients presenting to outpatient medical care facilities

Methicillin-resistant Staphylococcus aureus (MRSA) is a significant pathogen in both human and veterinary medicine. The importance of companion animals as reservoirs of human infections is currently unknown. The companion animals of 49 MRSA-infected outpatients (cases) were screened for MRSA carriage, and their bacterial isolates were compared with those of the infected patients using Pulsed-Field Gel Electrophoresis (PFGE). Rates of MRSA among the companion animals of MRSA-infected patients were compared to rates of MRSA among companion animals of pet guardians attending a “veterinary wellness clinic” (controls). MRSA was isolated from at least one companion animal in 4/49 (8.2%) households of MRSA-infected outpatients vs. none of the pets of the 50 uninfected human controls. Using PFGE, patient-pets MRSA isolates were identical for three pairs and discordant for one pair (suggested MRSA inter-specie transmission p-value = 0.1175). These results suggest that companion animals of MRSA-infected patients can be culture-positive for MRSA, representing a potential source of infection or re-infection for humans. Further studies are required to better understand the epidemiology of MRSA human-animal inter-specie transmission.     

Dietary choices are influenced by genotype,mating status,and sex in Drosophila melanogaster

Mating causes many changes in physiology, behavior, and gene expression in a wide range of organisms. These changes are predicted to be sex specific, influenced by the divergent reproductive roles of the sexes. In female insects, mating is associated with an increase in egg production which requires high levels of nutritional input with direct consequences for the physiological needs of individual females. Consequently, females alter their nutritional acquisition in line with the physiological demands imposed by mating. Although much is known about the female mating‐induced nutritional response, far less is known about changes in males. In addition, it is unknown whether variation between genotypes translates into variation in dietary behavioral responses. Here we examine mating‐induced shifts in male and female dietary preferences across genotypes of Drosophila melanogaster. We find sex‐ and genotype‐specific effects on both the quantity and quality of the chosen diet. These results contribute to our understanding of sex‐specific metabolism and reveal genotypic variation that influences responses to physiological demands.     

Progeny: Sperm ratios and segregation-distorter inDrosophila melanogaster

Progeny: sperm ratios (P/S) were determined from crosses ofSD/cn bw males ofDrosophila melanogaster with females of eight different genotypes. Thek value was about 1.0. P/S ratios of 0.88, 0.81, and 0.76, respectively, were observed from crosses with females of three genotypes, and ratios in the 0.3–0.4 range from five. These results support the suggestion ofZimmering & Fowler (1968) that P/S ratios may vary widely and depend at least in part on the genotype of the female. Morcover, since P/S ratios of 0.9 may be observed whenk is about 1.0, it follows that the vast majority of sperm stored in these females areSD.Supported by NSF grant GB 8565.NSF Undergraduate Research Participant.