Microtubule‐associated epithelial protein E‐MAP‐115 is localized in the spermatid manchette

SummaryA microtubule‐associated protein E‐MAP‐115 has been originally isolated and characterized from HeLa cells. Because of its predominant expression in cultured cells of epithelial origin, it has been suggested to be involved in the regulation of cell polarization. The present immunocytochemical, Northern blot and in situ hybridization analysis of E‐MAP‐115 in the mouse and rat seminiferous epithelium indicates its distinct association with the spermatid manchette, a unique microtubular structure which appears in the cytoplasm of spermatids at step 8 when nuclear polarization and elongation starts. At steps 15–16 when manchette has been disassembled, immunoreactivity for E‐MAP‐115 disappeared. At immunoelectron microscopical level, E‐MAP‐15 was associated with the microtubules of the manchette. In the Western and Northern blot analysis, a distinct stage‐dependent expression of a single E‐MAP‐115 polypeptide and two mRNA species (3.4 and 2.4 kb) could be identified. MTEST 60, a spermatid‐specific transcript, showed a 100% homology over region of 68–193 bp of E‐MAP‐115 sequence. The reported specific localization of E‐MAP‐115 to the spermatid manchette strongly supports its role as a regulator of cell polarization. This, in turn, supports the hypotheses concerning the dynamic function of the manchette during spermiogenesis

The Role of Prior Knowledge and Students’ Perceptions in Learning of Biomedical Sciences

The present study investigates whether medical students’ prior knowledge and perceptions about basic biomedical sciences predict learning of these topics at early phases of the medical education. Participants (N = 115) were first year medical students at the University of Turku (Finland). The data consisted of a student perception questionnaire, entrance examination results, and the examination scores of the first year preclinical courses. Compared to the students having only education at the upper secondary school level (n = 58), the students with prior university studies in sciences (n = 57) performed better in the first year course examinations. Out of the four entrance examination subtests, only the subtest in biology predicted performance in the first year course examinations. In terms of students’ perceptions, the students rated the courses that dealt with the human body on microscopic or molecular level the least useful and the most difficult. Yet, the perception of usefulness had no effect on examination performance. The results emphasize the role prior knowledge especially in biology has for learning of medicine. Furthermore, the first year medical students seem to value topics that are more closely related to their everyday experiences and, therefore, perhaps less abstract. The courses on cellular and molecular levels were rated notably low with regard to usefulness. The relevance of cellular and molecular biology to medical profession should be communicated more clearly to the students. Furthermore, basic science topics may benefit from a more integrative pedagogical approach in which the biomedical concepts are conceptualized in diagnostic practice.</p

Morphological abnormalities in gonads of the Baltic herring (Clupea harengus membras) in the northern Baltic Sea.

Reproductive disorders are a major environmental concern in the Baltic Sea, due to heavy anthropogenic influence and long- and short-term variations taking place in the natural environment. We report here an increasing prevalence of gonadal malformations in the Baltic herring (Clupea harengus membras),a key species of the Baltic ecosystem and important in commercial fishery.</p

Number of cells positive for proliferating cell nuclear antigen immunocytochemistry is lower in bovine in vitro-produced embryos vitrified on day 8 than on day 7

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