Worcester Foundation for Biomedical Research

About: Worcester Foundation for Biomedical Research is a based out in . It is known for research contribution in the topics: Estrone & Estrogen. The organization has 2195 authors who have published 2646 publications receiving 115809 citations. The organization is also known as: Worcester Foundation for Experimental Biology.

Metabolism of round spermatids from rats: lactate as the preferred substrate

Abstract: Round spermatids were prepared from rat testes and incubated with various substrates (glucose, fructose, pyruvate, lactate and acetate) to measure utilization of substrates and production of ATP in the presence of saturating levels of each substrate. By both criteria lactate is the preferred substrate by a factor of 3 or 4. Production of more than half of the ATP with lactate is substrate is prevented by addition of an inhibitor of alpha-ketoacid dehydrogenase (5-methoxyindole-2-carboxylic acid) Pyruvate and lactate are interconverted and pyruvate inhibits production of ATP from lactate. Synthesis of ATP with lactate and with pyruvate is inhibited by rotenone, rutamycin or 2,4-dinitrophenol. Utilization of glucose is limited by aldolase activity. These findings suggest that exogenous lactate is oxidized by lactate dehydrogenase followed by pyruvate dehydrogenase and Krebs; cycle enzymes under conditions which do not allow pyruvate to inhibit lactate dehydrogenase. ATP is synthesized through electron transport. Post-mitochondrial supernate from spermatids showed that high concentration of pyruvate (greater than 1 mM) inhibit lactate dehydrogenase with pyruvate as substrate and that with lactate as substrate, pyruvate behaves as a competitive inhibitor of lactate dehydrogenase. Evidently lactate is the preferred substrate for round spermatids and energy production is most efficient when this substance is present in high concentrations and pyruvate is present in low concentrations. Reasons are given for suggesting that Sertoli cells may provide the relatively large amounts of lactate required by round spermatids.

Inhibition of human immunodeficiency virus in early infected and chronically infected cells by antisense oligodeoxynucleotides and their phosphorothioate analogues

Abstract: Antisense oligodeoxynucleotides, both the phosphorothioate analogues and unmodified oligomers of the same sequence, inhibit replication and expression of human immunodeficiency virus already growing in tissue cultures of MOLT-3 cells with much greater efficacy than do mismatched ("random") oligomers and homooligomers of the same length and with the same internucleotide modification This preferential inhibitory effect is elicited in as short a time as 4-24 hr postinfection Likewise, antisense oligomers exhibit greater inhibitory effects on human immunodeficiency virus in chronically infected cells than do mismatched oligomers and homooligomers Phosphorothioate antisene oligomers are up to 100 times more potent than unmodified oligomers of the same sequence in these inhibitory assays These results, in major respects, confirm and extend those recently published by Matsukura et al [Matsukura, M, Zon, G, Shinozuka, K, Robert-Guroff, M, Shimada, T, Stein, C A, Mitsuza, H, Wong-Staal, F, Cohen, J S & Broder, S (1989) Proc Natl Acad Sci USA 86, 4244-4248] They also point out the importance of computer analysis of sequences though to be random but that in reality contain significant areas of likely hybridization, either to the viral genome or to the complementary DNA strand synthesized from it They thus reinforce the concept that specific base pairing is a crucial feature of oligonucleotide inhibition of human immunodeficiency virus

Fertilization of Denuded Rabbit Eggs in vitro by Sperm recovered from the Uterus or Vagina

Abstract: RECENTLY shed eggs are surrounded by a sticky mass of follicular cells known as the cumulus oophorus. The follicular cells, which are closely attached to the zona pellucida and are arranged in a compact radial pattern, are called the corona radiata. It has been postulated that the follicular cells in the cumulus oophorus can protect the egg against polyspermic fertilization, and can improve the chance of fertilization by providing a large target for the sperm. Further, due to the radial arrangement of the corona radiata, these follicular cells can act in orientating the sperm towards eggs1. After the dissolution of cumulus oophorus by treatment with hyaluronidase in vitro, however, rabbit eggs can be fertilized when transferred into the tubes of mated rabbits2,3. After the dissolution of cumulus oophorus and removal of the corona radiata by manual shaking, the denuded eggs can also be fertilized in vitro4 or in vivo5,6. A comparison of the proportion of eggs fertilized in vitro between denuded eggs and those with follicular cells intact has not been made. In addition, it has been speculated that the progesterone present in the follicular fluid or synthesized by the granulosa cells may be necessary for the “acrosome reaction”, capacitation of sperm, and the fertilization of eggs in vitro7. The experiment described here demonstrates (1) that denuded rabbit eggs lacking follicular cells (or progesterone) can be fertilized equally as well as intact eggs with cumulus oophorus, and (2) that sperm recovered from the vagina can fertilize rabbit eggs in vitro as well as those recovered from the uterus.