Study of chromosomal and nucleolar aspects in testes of Nysius californicus (Heteroptera: Lygaeidae)

In Nysius californicus (family Lygaeidae, subfamily Orsillinae), a pest commonly known as the seed bug, the chromosome complement is 2n = 16 (12A + 2m + XY), testes are formed by seven seminiferous tubules covered by an orange-colored membrane, and spermatogenesis is cystic. At prophase, sex chromosomes are heteropycnotic and autosomes usually show a chiasma. At metaphase, sex chromosomes along with microchromosomes may be seen located at the center of a ring formed by the remaining autosomes. A characteristic specific of N. californicus was the presence of nucleolar material observed from the cystic cell to the completely differentiated spermatozoon.Variations in size, shape and location of the nucleolar material occur during this process, denoting a variable degree of activity in the different stages.

STUDIS ON STRUCTURE KARYOTYPE AND BEHAVIOR OF THE SYNAPTONEMAL COMPLEX IN SPERMATOCYTES OF HEDGEHOG ERINACEUS EUROPAEUS IN SPER DEALBATUS INSECTIVORA / 解剖学报

The structure, karyotype and behavior of synaptonemal complex (SC) in the spermatocytes of hedgehog (Erinaceus euroaaus dealbatus (insectivora)) were analyzed by light and electron microscopy with a modified surface spread preparation which involves the use of sodium dodecyl-sulphate (SDS) and silver staining. The lateral elements of the synaptonemal complex have a constant width of about 50 nm, the distance between the two lateral elements is about 100 nm. The relative length and arm rationale constant for each autosomal SC. The relative length and arm ratio constant for ea of the autosomal SCs are very similar to that of mitotic autosome.The X and Y chromosome axes have a clear morphological distinction from the autosomal SC. The axes of X and Y chromosome pair and form a SC of certain length at pachytene stage. The axes of unpaired X and Y chromosome are heteropycnotic and display various morphological complexities. But these differentiations in hedgehog are primary than in other mammalians, such as human and mice. At pachytene stage the X and Y chromosome display an extensive side-by-side pairing segment with decreasing length as meiotic prophase progressed.