An Improved High Yield Total Synthesis and Cytotoxicity Study of the Marine Alkaloid Neoamphimedine: An ATP-Competitive Inhibitor of Topoisomerase IIα and Potent Anticancer Agent

Recently, we characterized neoamphimedine (neo) as an ATP-competitive inhibitor of the ATPase domain of human Topoisomerase IIα. Thus far, neo is the only pyridoacridine with this mechanism of action. One limiting factor in the development of neo as a therapeutic agent has been access to sufficient amounts of material for biological testing. Although there are two reported syntheses of neo, both require 12 steps with low overall yields (≤6%). In this article, we report an improved total synthesis of neo achieved in 10 steps with a 25% overall yield. In addition, we report an expanded cytotoxicity study using a panel of human cancer cell lines, including: breast, colorectal, lung, and leukemia. Neo displays potent cytotoxicity (nM IC₅₀ values) in all, with significant potency against colorectal cancer (lowest IC₅₀ = 6 nM). We show that neo is cytotoxic not cytostatic, and that neo exerts cytotoxicity by inducing G2-M cell cycle arrest and apoptosis.     

Trace Elements and Heavy Metals in Asian Rice-Derived Food Products

With the increase in the occurrence of heavy metal polluted rice in Asian countries, food safety of rice products is of utmost concern to consumers. The current study discusses the distribution of trace elements Cr, Cu, Zn, As, Se, Cd, Hg, and Pb in Asian rice-derived food products. Three types of food products, rice noodles, rice vinegar/wine, and rice snacks, were chosen for examination. Most toxic heavy metals and metalloid such as As, Cd, Hg, and Pb were found to be within the safe level of EPA. Since rice vinegar/wine is not the staple food for people, there is no noticeable safety concern. Rice noodles and snacks are consumed with noticeable Se content and they are possible for human Se source addition. With comparison with raw rice, rice-derived food products showed better quality in terms of toxic heavy metals and metalloids. This study is for the first time reporting a thorough understanding of safety concern of rice-derived food products. It provides baselines and understanding on current levels of trace elements and heavy metals in Asian-derived rice products as affected by food processes. It would also help consumers build up confidence on the food safety of Asian rice products.     

Maternally-derived antibodies to porcine parvovirus and their effect on active antibody production after vaccination with an inactivated oil-emulsion vaccine

Two sows which had been vaccinated with an oil-emulsion porcine parvovirus vaccine, and had developed high haemagglutination-inhibiting antibody levels to the virus, farrowed three successive litters each, a total of 74 piglets. Serum samples from these piglets were tested for haemagglutination-inhibiting antibody at birth, three and 17 days after birth, and at monthly intervals thereafter to study the decline of maternally-derived antibody. Regression curves were constructed from the data to show the projected pathway (mean and 95 per cent tolerance limits) of the decline of maternally-derived antibody. Approximately half the pigs still had positive titres of up to 1/160 at six months old, and traces of antibody were detected in a few pigs at nine months. Thus, even at the onset of breeding some gilts can have maternally-derived antibody which may interfere with their ability to develop active immunity to porcine parvovirus. From the same litters three groups of 12 pigs were selected randomly and were vaccinated with a single dose of the oil-emulsion vaccine at 70 days, 130 days or 190 days respectively. Despite the presence of moderate to high titres of maternally-derived antibody, especially in the younger pigs, all of those vaccinated showed strong and long lasting antibody responses to the vaccine. High serum antibody titres at the time of vaccination seemed to depress the response to the vaccine slightly but the effect was not statistically significant. These results have important implications for prevention of reproductive failure induced by porcine parvovirus.     

Prevalence of Salmonella spp on conventional and organic dairy farms

OBJECTIVE: To describe the occurrence of fecal shedding, persistence of shedding over time, and serogroup classification of Salmonella spp on a large number of dairy farms of various sizes. DESIGN: Longitudinal study. SAMPLE POPULATION: 22,417 fecal samples from cattle and 4,570 samples from the farm environment on 110 organic and conventional dairy farms in Minnesota, Wisconsin, Michigan, and NewYork. PROCEDURE: 5 visits were made to each farm at 2-month intervals from August 2000 to October 2001. Fecal samples from healthy cows, calves, and other targeted cattle groups and samples from bulk tank milk, milk line filters, water, feed sources, and pen floors were collected at each visit. Bacterial culture was performed at 1 laboratory. RESULTS: Salmonella spp were isolated from 4.8% of fecal samples and 5.9% of environmental samples; 92.7% of farms had at least 1 Salmonella-positive sample. The 75th percentile for median within-herd prevalence of Salmonella spp in cattle for 5 sampling visits to a given farm was 2.0% and for maximum within-herd prevalence of Salmonella spp was 13.6%. Farms with a median within-herd prevalence of Salmonella spp of > or = 2.0% accounted for 76.3% of Salmonella-positive samples. There was no significant difference in the prevalence of Salmonella spp between conventional and organic farms. Seasonal differences in Salmonella shedding were observed. More farms had at least 1 serogroup B isolate than any other serogroup, whereas serogroup E1 was the most common among all Salmonella-positive samples. More than 1 serogroup was isolated on 76.4% of Salmonella-positive farms. CONCLUSIONS AND CLINICAL RELEVANCE: Salmonella spp were isolated from > 90% of dairy farms; however, 25% of farms accounted for > 75% of Salmonella-positive samples. This information is critical for the direction of intervention strategies to decrease the prevalence of Salmonella spp on dairy farms.     

Variations in the number of nucleoli in the granulosa cells of the domestic fowl during follicular growth

1. The proportions of granulosa cells containing one, two, or more nucleoli were determined in ovarian follicles of the domestic fowl (Gallus domesticus). Follicles ranged in size from 5 to 37 mm diameter.

2. The greatest proportion of cells (65%) contained one nucleolus. Cells containing two nucleoli were fewer (29%) and those containing more than two were rare (6%).

3. There was a tendency for the proportion of multinucleolar cells to decrease with increasing size of the follicle. Conversely there was a similar tendency for the proportion of cells with single nucleoli to increase with size of the follicle. These relationships are curvilinear.

4. Suitable linear models confirmed these observations (P < 0.005).

5. These results may provide an explanation for the previously reported progressive decrease in cellular DNA as the follicle increases in size.     

Garlic and papaya lack control over gastrointestinal nematodes in goats and lambs

Gastrointestinal nematodes (GIN) continue to hinder small ruminant production because of anthelmintic resistance and lack of effective products for GIN control in organic production. The objective of this study was to examine the effectiveness of a commercially available certified organic garlic product, fresh garlic juice, or garlic bulbs as an anthelmintic to control GIN in goats and papaya seeds for GIN control in lambs. In the first experiment, weaned meat goat kids were administered water or a commercial garlic juice product (n = 7/treatment). In the second experiment, kids were administered water, fresh garlic juice, or fed garlic bulbs (n = 9 or 10/treatment). In a third experiment, lambs were administered nothing or papaya seed in water (n = 12/treatment). Naturally infected goats were supplemented with bermudagrass hay and corn/soybean supplement in the first experiment or maintained on bermudagrass pasture in the second experiment or lambs grazed mixed grasses in the third. Blood and fecal samples were collected on Days 0, 7, and 14 after administration of treatment to examine changes in blood packed cell volume (PCV) and fecal egg counts (FEC). PCV and FEC were similar by Day 14 between kids treated with a commercial garlic juice and water in the first experiment. Similarly, PCV was not different among treatment groups in the second experiment. FEC of the garlic juice group was lower than the other two groups on Day 0, but was similar among groups by Day 14. Deworming was required in one goat within each treatment group by Day 7 and in three kids in the garlic juice group and two in the garlic bulb group by Day 14. No changes in PCV or FEC were apparent in response to papaya seed compared with untreated lambs. Based on the alternative plant products used in this study, garlic or papaya seed is not recommended as an aid to control GIN in goats or lambs.     

Amplified fragment length polymorphism to detect clonal diversity and distribution of Mycobacterium avium subspecies paratuberculosis in selected Minnesota dairy cattle.

The molecular ecology of Mycobacterium avium subspecies paratuberculosis (MAP), the causative agent of Johne's disease, is not well understood in the United States. In this study, a DNA fingerprinting method, amplified fragment length polymorphism (AFLP), was used to subtype the pathogen and assess the clonal diversity of MAP in Minnesota dairy herds. Fifty-six fecal culture test-positive isolates from various Minnesota counties and culture dates were analyzed in this study. The AFLP identified 11 profiles with 50% of isolates representing 1 major profile. The major profile was distributed across the state. The genetic diversity of bovine MAP clones in Minnesota based on AFLP analysis of this data appears to be relatively low.