Van der Meer J M
J Embryol Exp Morphol. 1979 Jun;51:1-26.
Eggs of the pea-beetle Callosobruchus were divided into two at different stages of development. Both fragments were allowed to develop into partial larvae. The segment patterns of normal and partial larvae are described using cuticular markers of cell differentiation. To study the contribution of cytological damage to the segment gap phenomenon three different types of constriction were performed: complete and incomplete permanent constriction and complete temporary constriction. Changes in the structure of the egg can produce absence of segments resulting from two different effects. First, partial absence of segments results from a decreased egg circumference in the constriction region and involves the disturbance of a morphogenetic process (dorsal closure). Secondly, cytological damage can result in a gap between two arrays of segments. The loss of segments in the gap occurred in two different ways. In a spatial segment gap the two arrays of segments were physically discontinuous, whereas in a non-spatial gap the segments bordering the gap were juxtaposed in a physically continuous cuticle. The extent to which the gap phenomenon can be attributed to cytological damage is discussed. We also discuss, on the basis of certain dorsal defects, a possible stepwise specification of the dorsal transverse cuticular pattern.
豌豆象鼻虫Callosobruchus的卵在不同发育阶段被分成两部分。两部分都被允许发育成部分幼虫。使用细胞分化的表皮标记描述正常幼虫和部分幼虫的节段模式。为了研究细胞学损伤对节段间隙现象的影响，进行了三种不同类型的缢缩：完全和不完全永久性缢缩以及完全临时性缢缩。卵结构的变化可因两种不同效应导致节段缺失。首先，节段部分缺失是由于缢缩区域卵周长减小，并涉及形态发生过程（背侧闭合）的紊乱。其次，细胞学损伤可导致两排节段之间出现间隙。间隙中节段的缺失以两种不同方式发生。在空间节段间隙中，两排节段在物理上不连续，而在非空间间隙中，与间隙相邻的节段在物理上连续的表皮中并列。讨论了间隙现象可归因于细胞学损伤的程度。我们还根据某些背侧缺陷，讨论了背侧横向表皮模式可能的逐步特化。
