The Spermatid Cell Membrane in Melanoplus differentialis

1. The cell membrane of the spermatid of the grasshopper Melanoplus differentialis is shown to be composed of a double-layered membrane 10 mµ thick. Closely applied to this is an additional outer covering 25 to 35 mµ thick which has a regular geometrical pattern. 2. Models of cell membrane structure are discussed briefly. It is suggested that the pattern results from preferential adsorption of material onto a particular component of the double-layered membrane.     

Characterization of apolipophorin III from Barytettix psolus and Melanoplus differentialis

Apolipophorin III has been isolated and characterized from two orthopteran species, Barytettix psolus and Melanoplus differentialis. Both apoLp-IIIs have M_r ∼ 20,000 and contain 5% covalently bound sugar. Compositional analysis of the carbohydrate component of these apoLp-IIIs, as well as Locusta migratoria apoLp-III, revealed the presence of manose, fucose and N-acetyl glucosamine. In all three proteins the ratios of these sugar residues was similar (∼2:2:1). Amino acid analysis of B. psolus and M. differentialis apoLp-IIIs was performed and the results compared with those from L. migratoria and M. sexta apoLp-IIIs. The three orthopteran apoLp-IIIs possessed very similar compositions that were distinct from that of M. sexta. Similarly, N-terminal sequence analysis revealed ∼50% sequence identity between the three orthopteran apoLp-IIIs but only 9–18% identity was observed when B. psolus or M. differentialis apoLp-IIIs were compared to M. sexta apoLp-III. The implications of these findings, with respect to flight-related physiology and adipokinetic hormone stimulated lipid mobilization in these different species, is discussed.     

Compensatory feeding in response to variable food quality by Melanoplus differentialis

Abstract. The behavioural mechanisms driving compensatory food consumption in response to dietary dilution as well as the relationship between feeding time and food residence time (i.e. digesta retention time in the gut) were studied using the non-diapausing strain of the grasshopper Melanoplus differentialis (Thomas) (Orthoptera: Acrididae). 3-day-old, sixth-instar nymphs and 3-day-old adults were fed artificial diets containing 1%, 3% and 5% total nitrogen (N) at 30C, LD 14:10h; the feeding behaviour was recorded using electronic monitoring devices connected to microcomputers for 24 h. The percentage of time spent feeding increased linearly as diets were diluted using non-digestible cellulose from 5% to 1% N. This response was due to an increase in the number of meals while the meal duration of a feeding bout was unaltered. Sixth-instar nymphs spent about 40% more time feeding than the larger adults. The increased feeding time in nymphs resulted from both more frequent feeding bouts and longer meal duration. Feeding time and food residence time were highly negatively related.     

Leaf wilting alters a plant species ranking by the grasshopper Melanoplus differentialis

Abstract. 1. Field observations of the feeding behaviour of the polyphagous grasshopper Melanoplus differentialis suggest that plant quality can override plant species as a determinant of choice. When offered binary choices in laboratory tests between leaves of two host plant species, Helianthus annuus and Ambrosia trifida , in all combinations of wilted and turgid, grasshoppers prefer A. trifida in all test conditions, except when it is turgid and H.annuus is wilted. In this case, the preference switches to H.annuus
2. Preliminary evidence suggests that chemical factors are responsible for the alteration in preference.     

Comprehensive analysis of the complete mitochondrial genome of Melanoplus differentialis (Acrididae: Melanoplinae) captured in Korea

In this study, we determined the complete mitochondrial genome of the invasive insect species Melanoplus differentialis captured in Korea. The complete mitochondrial genome of M. differentialis is 15,625 bp long and comprises 13 protein-coding genes, two ribosomal RNA genes, and 22 transfer RNAs, with a GC ratio of 25.2%. In total, 353 SNPs and 11 INDEL regions (total length 67 bp) were found against the previously sequenced M. differentialis mitochondrial genome recorded as public genome data. The number of interspecific variations was greater than the number of intraspecific variations in this insect. Phylogenetic tree analysis showed that the mitochondrial genome clustered the Melanoplus clade with two previously reported Melanoplus sequences. However, the sequences were not divided at the species-level clade possibly as a consequence of misidentification caused by an error in the public database. Our results extend the molecular database status of Melanoplus by providing a novel complete mitochondrial genome sequence for M. differentialis that could serve as reference for further molecular studies.     

Intranuclear and cytoplasmic annulate lamellae in grasshopper spermatocytes (Genus Melanoplus)

Intranuclear and cytoplasmic annulate lamellae were studied in grasshopper spermatocytes (Melanoplus) with the electron microscope. Although cytoplasmic annulate lamellae were observed in all three species examined, intranuclear annulate lamellae were found in only one species. The intranuclear annulate lamellae encompass certain nuclear material adjacent to the nuclear envelope forming a vesicle that is extruded into the spermatocyte cytoplasm. In this same species, cytoplasmic annulate lamellae are seen contiguous with granular masses of varying size. These structures were noted as being morphologically indistinguishable from the "yolk nuclei" of dragonfly oocytes (Kessel and Beams, 1969; Kessel, 1973).     

Re-analysis of the methylalkanes of the grasshoppers,Melanoplus differentialis,M. packardi and M. sanguinipes

Gas chromatography-mass spectrometry was used to determine the structures of the methyl branched alkanes of the grasshoppers Melanoplus differentialis (Thomas), M. packardii (Scudder) and M. sanguinipes (Fabricius). The branched hydrocarbons were composed of 2- and 3-methylalkanes and internally branched mono- and di-methylalkanes. The major dimethylalkanes were a homologous series from C₃₃ to C₅₅ and had nine methylenes between the branch points rather than three as reported by Soliday et al. (1974) for M. packardii and M. sanguinipes. Unexpectedly, the homologous series with nine methylenes between branch points did not extend to the C₃₁ dimethylalkanes. The C₃₁ dimethylalkanes were identified as 9,21-dimethylhentriacontane (11 methylenes between the branch points) in M. packardii and M. Sanguinipes and 11,19-dimethylhentriacontane (seven methylenes between the branch points) in M. differentialis.     

Labelling of the chromatid body by [3H]uridine in rat pachytene spermatocytes

In this study it is shown that a cytoplasmic cell organelle, the chromatoid body, becomes labelled with [³H]uridine in the pachytene spermatocytes. The chromatoid body becomes labelled when the cells are first labelled for 2 h in the presence of [³H]uridine and thereafter chased for 9 h in the presence of unlabelled uridine. This labelling is inhibited by the specific RNA polymerase II inhibitor α-amanitin. Based on this it is suggested that part of the RNA synthesized in the pachytene spermatocytes is stored in the chromatoid body and transported to the postmeiotic spermatids where it is used in the differentiation of the spermatids.     

Amoebogregarina Nigra n. gen., n. comb. (Apicomplexa: Gregarinidae) from adult Melanoplus differentialis (Orthoptera: Acrididae) in southeastern Nebraska

Amoebogregarina nigra n. gen., nov. comb. (Eugregarinida: Gregarinidae) is described from trophozoites, gamonts, associations, gametocysts, and oocysts collected from adult Melanoplus differentialis (Orthoptera: Acrididae) in Nemaha County, Nebraska. Host alimentary canals were examined for eugregarine parasites. Gregarines encountered were fixed as permanent specimens or subjected to a series of morphometric measurements. Morphometric analysis indicated the presence of Gregarina nigra, a poorly described taxon reported from a variety of Nearetic grasshopper species, Examination of G. nigra revealed a metamorphic epimerite assimilated by the protomerite on maturity. This epimerite-protomerite complex is unique within Gregarinidae, prompting creation of the genus Amoebogregarina. Amoebogregarina nigra is the type species in new combination. Gregarina indianensis is recognized as a junior synonym of A. nigra.     

组蛋白H3Ser10磷酸化在家蚕精母细胞减数分裂中的动态分布

【目的】探究组蛋白H3Ser10磷酸化(H3Ser10ph)在家蚕Bombyx mori精母细胞减数分裂中的功能。【方法】解剖并分离家蚕4龄幼虫至蛹期精巢组织,通过丙烯酰胺凝胶包埋制备处于减数分裂不同时期的精巢组织玻片,以免疫荧光标记检测H3Ser10ph抗体在精母细胞减数分裂不同时期的定位特点。【结果】在家蚕有核精子精母细胞减数分裂过程中,组蛋白H3Ser10的磷酸化发生在粗线期染色体的特定位置,双线期H3Ser10ph信号逐渐减弱,至终变期时在染色体上完全检测不到磷酸化信号。随着细胞周期的进行,磷酸化信号又开始逐渐增强,减数第一次分裂中期时达到最高水平。当细胞进入减数第二次分裂前中期时,染色体臂上的H3Ser10ph信号消失,在靠近纺锤体微管的分裂面处有弥散的H3Ser10ph抗体的信号,减数第二次分裂末期,仅剩余非常微弱的H3Ser10ph信号残留于染色体的特定位置。在无核精子精母细胞减数分裂过程中,在中期I至末期I一直在染色体上有较均一的3Ser10ph信号,后期I时纺锤丝微管与赤道面平行。【结论】组蛋白H3Ser10磷酸化与家蚕有核精子和无核精子精母细胞减数分裂中染色质的动态变化相关。