Male sterility in a petunia cytoplasmic male sterile line has been attributed to the early appearance of active callase, a beta-1,3-glucanase, in the anther locule. This leads to premature dissolution of the callose walls surrounding the microsporogenous cells. We have mimicked this aspect of the petunia line in transgenic tobacco by engineering the secretion of a modified pathogenesis-related vacuolar beta-1,3-glucanase from the tapetum prior to the appearance of callase activity in the locule. Plants expressing the modified glucanase from tapetum-specific promoters exhibited reduced male fertility, ranging from complete to partial male sterility. Callose appearance and distribution are normal in the male sterile transgenic plants up to prophase I, whereupon callose is prematurely degraded. Meiosis and cell division occur normally. The resultant microspores have an abnormally thin cell wall that lacks sculpturing. The tapetum shows hypertrophy. Male sterility is probably caused by bursting of the aberrant microspores at a time corresponding to microspore release. These results demonstrate that premature callose degradation is sufficient to cause male sterility and suggest that callose is essential for the formation of a normal microspore cell wall.

This fascinating text, first published in 1875, is a key early example of the conflict thesis. This theory expounds the premise of an intrinsic conflict between science and religion, and is archetypal of one aspect of this late-Victorian debate. Draper asserts that science has reached a point where its threat to traditional teachings can no longer be ignored, and he offers this history as a means to understanding both the interaction between religion and science and their perpetual opposition. He covers examples of this relationship, from Christianity's origins to the then contemporary crisis of church division and the Prussian–Austrian war, and also examines in turn what both Christianity and science have done for modern civilisation. Discussions of the central points of crossover and change in the history of science and Christianity lead to the conclusion that for religion to survive it must accept fact and reason.

The expression and sequences of two related antherspecific cDNAs (I3 and C98) of Brassica napus (oilseed rape) were examined. These cDNAs were found to exhibit significant predicted amino acid sequence similarity with a group of seed-specific proteins, the oleosins, which are involved in oil body membrane structure. Pollen of B. napus also contains oil bodies, and the synthesis and accumulation of these organelles correlates with expression of the I3 and C98 transcripts. The protein content of purified pollen oil bodies was therefore examined in order to determine the presence or absence of possible oleosins. One major protein species of 14 kDa was identified and subjected to N-terminal amino acid sequence determination. The sequence of this pollen oil body associated protein is homologous to the predicted sequence of one of the anther-specific cDNs, I3, implying that this cDNA represents an anther-specific oleosin gene expressed in developing pollen. The expression of other genes active during seed oil body formation was also examined, and these were found to be specific to the sporophyte, inferring the existence of specific components of the pathway of lipid synthesis and storage in the male gametophyte. These possibilities and the relationship between different oleosin genes are discussed.

A seri es of selected or specially prepared catalysts were s tud ied fo r t heir abili ty to accelerate the ortho to para conversion of hydrogen . The res ults of t hi s st ud y a re presented and the p erformance of vari ous catalyst s are compared with t hat of chrom ic oxide on al u: mina pellets. An outstandin g cata.lyst, u~s upporte d hydrous J erric oxide g ra nules, was selected for further study a nd used 111 the liquefi ers of t he NatIOnal Burea u of Standards Cr yogenic Engineering L aboratory. One and one-half liters of t his catalyst has now bee n used to convert more t han 100,000 li ters of liquid hydrogen to 90 to 95 perce nt pa ra at an average rate of abo ut 235 liters of liquid per hour. There is to date no ev id ence of decrea se in effici ency with continued use.

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