Colman O D, Stockert J C
Chromosoma. 1975 Dec 29;53(4):381-92. doi: 10.1007/BF00294085.
The puffing pattern of polytene chromosomes in salivary glands from Chironomus pallidivittatus larvae and prepupae has been studied in glutaraldehyde-acetic acid fixed, lactic acid flattened preparations. Some observations were also made on F1 hybrid species C. pallidivittatus X C. tentans. Concerning the situation of puffing in Balbiani rings (BR), 2.783 chromosomes IV from 188 animals were scored. In standard 4th instar larvae, BR2 appears expanded, BR3 smaller but not collapsed and BRI either reduced of collapsed. During the first days following the red-head stage, which signals the beginning of the 4th instar, larvae show a large BR1; later it reduces and tends to collapse. At the end of the 4th instar, prepupae again may present an expanded BR1. On the contrary, the size of BR2 and BR3 remains unchanged from the red-head stage to the prepupa. A variable accumulation of droplets has been observed to occur in BR2 and BR1 from dated larvae and prepupae.--A characteristic pattern of puffing was found in prepupae, which consisted in the appearance of conspicuous puffs at regions I-6B, I-7B, I-7B, I-18C, III-9B and IV-4B. Puffs at I-2B, I-3B, I-9A,I-11C,II-4A, and IV-4B were observed during most of the 4th larval instar, as well as in late larvae and prepupae. Among all these puffs, those at I-7B, I-9A, I-17B, and IV-4B frequently showed variable amounts of droplets.
对苍白摇蚊幼虫和蛹前期唾液腺中多线染色体的胀泡模式进行了研究，采用戊二醛 - 乙酸固定、乳酸压片制备。对F1杂交种苍白摇蚊×细摇蚊也进行了一些观察。关于巴尔比亚尼环（BR）中的胀泡情况，对188只动物的2783条IV号染色体进行了评分。在标准的四龄幼虫中，BR2呈现扩张状态，BR3较小但未塌陷，BR1则缩小或塌陷。在标志着四龄幼虫开始的红头期后的头几天，幼虫的BR1很大；之后它缩小并趋于塌陷。在四龄幼虫末期，蛹前期的BR1可能再次扩张。相反，从红头期到蛹前期，BR2和BR3的大小保持不变。在不同日期的幼虫和蛹前期的BR2和BR1中观察到有不同程度的液滴积累。——在蛹前期发现了一种特征性的胀泡模式，表现为在I - 6B、I - 7B、I - 7B、I - 18C、III - 9B和IV - 4B区域出现明显的胀泡。在四龄幼虫的大部分时间以及后期幼虫和蛹前期，在I - 2B、I - 3B、I - 9A、I - 11C、II - 4A和IV - 4B处观察到胀泡。在所有这些胀泡中，I - 7B、I - 9A、I - 17B和IV - 4B处的胀泡经常显示出不同数量的液滴。
