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Insects are the largest group of animals when it comes to the number and diversity of species. Yet, with the exception of Drosophila, no information is currently available on the primary structure of their sperm nuclear basic proteins (SNBPs). This paper represents the first attempt in this regard and provides information about six species of Neoptera: Poecillimon thessalicus, Graptosaltria nigrofuscata, Apis mellifera, Nasonia vitripennis, Parachauliodes continentalis, and Tribolium castaneum. The SNBPs of these species were characterized by acetic acid urea gel electrophoresis (AU-PAGE) and high-performance liquid chromatography fractionated. Protein sequencing was obtained using a combination of mass spectrometry sequencing, Edman N-terminal degradation sequencing and genome mining. While the SNBPs of several of these species exhibit a canonical arginine-rich protamine nature, a few of them exhibit a protamine-like composition. They appear to be the products of extensive cleavage processing from a precursor protein which are sometimes further processed by other post-translational modifications that are likely involved in the chromatin transitions observed during spermiogenesis in these organisms. [ABSTRACT FROM AUTHOR]

Sperm nuclear basic proteins (SNBPs) were isolated from extracted antheridia-rich male gametophytes raised from spores of the swordfern, Polystichum munitum. Electrophoretic (acetic acid-urea PAGE and SDS-PAGE) and chromatographic (rp-HPLC) characterization of the nuclear proteins exhibited the characteristics of the histone (H-type). In both types of gel electrophoresis, histones H1, H2A, and H2B showed an altered electrophoretic mobility corresponding to that which is routinely observed for the histones in other plants. Histones present during spermatogenesis of the fern P. munitum were compared with the few current SNBPs known to be present in higher and lower evolutionary plant clades. A transition from an early protamine (P-type) SNBPs in charophytes and bryophytes to the (H-type) SNBP observed here is reminiscent of similar reversions observed in the animal kingdom. [ABSTRACT FROM AUTHOR]

The conformational changes due to ATP binding to the chaperonin GroEL protein are examined using a mutant enzyme complexed with ATP. Results show that ATP binding changes the interaction pattern through the entire double ring structure.

An examination of membrane fusion in the Semliki Forest virus through cryoelectron microscopy revealed spike proteins in the spike complex. Under low pH, the spike structure undergoes unexpected conformational change. Mapping the location of the proteins through icosahedral reconstruction showed that conformational change caused by the cleavage of p62 results to movement and fusion activity between the structural proteins in the complex.

Abstract Background Two thaumatin-like proteins (TLPs) were previously identified in phloem exudate of hybrid poplar (Populus trichocarpa × P. deltoides) using proteomics methods, and their sieve element localization confirmed by immunofluorescence. In the current study, we analyzed different tissues to further understand TLP expression and localization in poplar, and used immunogold labelling to determine intracellular localization. Results Immunofluorescence using a TLP antiserum confirmed the presence of TLP in punctate, organelle-like structures within sieve elements. On western blots, the antiserum labeled two constitutively expressed proteins with distinct expression patterns. Immunogold labelling suggested that TLPs are associated with starch granules and starch-containing plastids in sieve elements and phloem parenchyma cells. In addition, the antiserum recognized TLPs in the inner cell wall and sieve plate region of sieve elements. Conclusions TLP localization in poplar cells and tissues is complex. TLP1 is expressed predominantly in tissues with a prominent vascular system such as midveins, petioles and stems, whereas the second TLP is primarily expressed in starch-storing plastids found in young leaves and the shoot apex.

Much progress has been made regarding our understanding of aromatase regulation, estrogen synthesis partitioning and communication between the germinal and somatic compartments of the differentiating gonad. We now know that most of the enzymatic and signaling apparatus required for steroidogenesis is endogenously expressed within germ cells. However, less is known about the expression and localization of steroidogenic components within mature spermatozoa. We have assembled a sperm library presenting 197,015 putative transcripts. Co-expression clustering analysis revealed that 6687 genes were present at higher levels in sperm in comparison to fifteen other salmon tissue libraries. The sperm transcriptome is highly complex containing the highest proportion of unannotated genes (45%) of the tissues analyzed. Our analysis of highly expressed genes in late-stage sperm revealed dedication to tasks involving chromatin remodeling, flagellogenesis and proteolysis. In addition, using various different embedding and microscopic techniques, we examined the morphology of salmon spermatozoa and characterized expression and localization of several estrogenic regulatory and signaling proteins by immunohistochemistry. We provide evidence for the endogenous synthesis and localization of aromatase (CYP19A and CYP19B1) and potential mediators of estrogen [i.e., ER-alpha and soluble adenylyl cyclase (sAC)] or phosphate (i.e., CREB and FOXL2A) signaling. Partitioning of select transcripts that encode AR-beta, FSH and the LH receptor, but not AR-alpha, LH or the FSH receptor, further points to localized specificity of function in the steroidogenic circuitry of the sperm cell. These results open new avenues of investigation to further our understanding of the intra- and intercellular regulatory processes that guide sperm development and biology. [ABSTRACT FROM AUTHOR]

Provides a rationale for allowing students to write in journals that the teacher will never read. Suggests requiring students to write responses to their journal writing at the end of the semester, which would be shared with the teacher and the rest of the class. Includes a sample response. (HTH)