Although Schistosoma japonicum egg granulomas are generally considered to be similar to those of S. mansoni (which are largely immunologic reactions of the delayed hypersensitivity type) there are suggestions that the histopathology and perhaps the etiology of the lesions are different. In mice with light S. japonicum infections, at 5 weeks after infection (2 weeks after egg production began), ...

I. The changes occurring in the free amino acids of the plasma of laying hens in relation to egg formation have been investigated in fed and starved hens in three experiments, each with eight birds. 2. The mean concentrations of most amino acids and of the totals were higher at night than in the morning. 3. In general, egg formation was associated with increases in the concentrations of nonesse...

In contrast to animals, plant germ cells are formed along with accessory cells in specialized haploid generations, termed gametophytes. The female gametophyte of flowering plants consists of four different cell types, which exert distinct functions in the reproductive process. For successful fertilization, the development of the four cell types has to be tightly coordinated; however, the underl...

The covering of the eggs in Russian sturgeon Acipenser gueldenstaedtii consists of three envelopes (the vitelline envelope, chorion and extrachorion) and is equipped with multiple micropyles. The most proximal to the oocyte is the vitelline envelope that consists of four layers of filamentous and trabecular material. The structural components of this envelope are synthesized by the oocyte (prim...

Sexual reproduction of flowering plants is distinguished by double fertilization—the two sperm cells delivered by a pollen tube fuse with the two gametic cells of the female gametophyte, the egg and the central cell—inside the ovule to give rise to the embryo and the nutritive endosperm, respectively. The pollen tube is attracted by nongametic synergid cells, and how these two cells of the fema...

ERK-type MAP kinase activity is required for normal first meiotic (MI) metaphase spindle dynamics and first polar body formation at the MI/MII transition, and for MII arrest until egg activation. MEK and MAPK, however, remain active until meiosis is completed and pronuclei form, but whether MEK/MAPK activity affects MII spindle function during egg activation has been unknown. Polarized light mi...

We have previously shown that Xenopus oocytes, eggs, and early embryos contain lamins LII and LIII, and that portions of each are associated with distinct egg vesicle populations. We now report that a lamin similar or identical to the B-type lamin LI is also present in oocyte nuclei and in egg extracts. We have quantitated the three B-type lamins per oocyte nucleus, and have calculated relative...

It has been suggested that follicle-stimulating hormone (FSH) may play a role in egg size/number trade-offs in oviparous vertebrates. We tested this hypothesis in an avian species by administering porcine FSH (pFSH) to intact, captive female zebra finches (Taeniopygia guttata) during egg formation. We predicted that (1) pFSH would increase the number of ovarian follicles recruited into rapid yo...