Testis composition

The above general scheme based on comparisons of the most evolutionarily conserved GHl domain does not reveal the rich microheterogeneity of linker histones which stems from differences between the less well conserved basic tails. Such variants, often referred to as somatic subtypes, occur in plants (for review see Ref. [80]) and animals, both invertebrates and vertebrates (for review see Refs. [81-83]). For example in mammals five somatic subtypes represent the major form of HI HF-1, HF-2, HF-3, HF-4, and HI a, according to the nomenclature proposed in Ref. [82]. The N- and C-terminal tails of the subtypes differ in length, the amino acid composition and the frequency and distribution of phosphorylation sites. The testis specific Hit can be considered the most diverged subtype of the major form. 

Perhaps the most remarkable feature of the SGG derived from testis is its extremely restricted alkyl and acyl composition. 

In the case of the SGG of rat (11,14), boar (12), guinea pig (13) and human (15,26) testis, over 80% of the alkyl and acyl composition is comprised of saturated 16 carbon moieties [glyceryl-1-hexadecyl ether (chimyl alcohol) and hexadecanoic acid (palmitic acid) respectively]. The SGG present in rat brain appears to have a less restricted alkyl and acyl composition (20). 

As many malignant tumors resemble fetal tissue in their biochemical composition, this result is consistent with the observed absence of SGG from immature human testis (15,26). Another tentative interpretation of this finding is that seminoma cells derive from a cell stage prior to that of the primary spermatocyte, thus accounting for their inability to synthesize SGG. 

The composition of the excreted urinary 17-ketosleroids also reveals a close similarity between the hormones of different origin the testis accounts for 30% while the adrenal cortex contributes the remaining 70% of the total urinary 17-ketosteroids [383]. Androsterone, ep a-androsterone, and 5/8-androsterone (etiocholanolone) are the main urinary metabolities of testosterone, and dehydroepiandrosterone is the major urinary 17-ketosteroid derived from the adrenal cortex. 

DESI, in contrast, and despite being a relatively new technique, has already delivered encouraging results in oncological research of lipids in the past few years. In a couple of sample-rich studies, lipid profiles were found to distinguish between diseased and healthy tissues from a variety of different cancers such as human prostate, colorectal, renal cell, bladder, and testis tumors (72-76). Moreover, Eberlin and coworkers reported the use of DESI lipid profiles for the determination of type, grade, and cell concentration in human brain tumors (77,78). DESI has not only been used in an oncological context. It was also used to image the lipid composition of arterial plaques (79). 

In vitro assay systems can also be used to show that ACAT uses oleoyl-CoA and palmitoyl-CoA preferentially as substrates [15,16,22]. This specificity is in good agreement with the fatty acid composition typically found upon analysis of tissue CE. However, some tissues, such as the rat adrenal, ovary, and testis, are rich in polyunsaturated fatty acids, raising the possibility that these tissues may contain an ACAT enzyme with a different fatty acid specificity [23]. 

The concentration of G in rabbit brain, thymus, lung, liver, stomach, intestine, kidney, testis, muscle, and erythrocyte tissues was determined. The neuraminic acid composition was also determined. iV-Glycolylneuraminic acid-containing Gm was found in thymus, lung, kidney, and intestine as well as A-acetylneuraminic acid-containing G, but JV-acetylneuraminic acid was the sole neuraminic acid of G from other tissue. 

Poly(ADP-ribose) synthetases were purified to apparent homogeneity from calf thymus, mouse testis, and human placenta. The major characteristics of these enzymes are presented in Table 1. In addition to molecular mass, sedimentation constant, isoelectric point, and partial specific volume, the apparent for NAD and DNA as well as V ,ax of the reaction are all common to these three enzymes. Amino acid compositions of the enzymes are shown in Table 2. Here again, the numbers of each amino acid residue are very similar to each other, although some differences as denoted by star symbols are noted. 

Table 1. Amino acid composition of ADP-ribosylated non-histone acceptor proteins purified from mouse testis nuclei ...

Table 2. Amino acid composition of the 70,000 Mj pared with protein PA (Table 1) E. Leone et al. LMG-like proteins from testis and liver com- ... 

Diets deprived of essential fatty acids (EFA) enhance the A6 desaturation activity of rat liver or testis microsomes. Changes of fatty acid composition with decrease of linoleic and arachidonic acids and increase of oleic and 20 3 (o)9) acids are shown as early as 3 days after EFA deprivation (Table 1). The changes evoke a decrease of the double bond index saturated acid ratio from 2.2 to... 

Burr Burr (1929, 1930) originally observed that essential fatty acids are necessary for the maintenance of normal testicular function in rats. Since then the lipid composition of testes and the metabolism of testicular lipids have been studied by many investigators in an attempt to relate these to the development and function of the testis. 

Dietary deficiency of vitamin E also leads to degeneration of the seminiferous tubules. Changes in the fatty acid composition of testes of rats receiving a vitamin E-deficient diet have been reported. An increase in arachidonic acid and in 22 4n-6 and a decrease in 22 5n-6 were found by Bieri Andrews (1964), who suggested that there might be a metabolic block in the conversion of 20 4 to 22 5 in vitamin E-deficiency. Witting et al. (1967) postulated that 22 5n-6 may be destroyed by peroxidation in the testis of the tocopherol-deficient rat, while Carney Walker (1971)... 

The final study to be described concerns the fatty acid composition of testicular lipids of a rat mutant-the restricted color (H ) rat. The germinal epithelium of the testis of this mutant develops more slowly than and not as extensively as that of the nonmutant control (Gumbreck et al., 1972). These investigators reported... 

For their study of the developmental changes in chromosomal composition and template activity during maturation of trout testis, Marushige and Dixon (1969) applied the method of Marushige and Bonner (1966) for liver chromatin and obtained testis chromatin with a consistent recovery of over 80% relative to DNA content. 

The biosynthetic development of protamine was first studied by analysis of amino-acid composition and terminal groups of proteins in the nuclei fraction from the testis of rainbowtrout (Salmo irideus) at different stages of spermatogenesis, as shown in Table X-2. These studies showed that in the immature stage DNA is bound to basic proteins of the histone type, which are gradually replaced as maturation proceeds by basic proteins of the protamine type, so that in the fully matured sperm heads DNA is bound only to protamine [Ando and Hashimoto, 1958 (1 2, 3) Felix 1958 Felix, I960]. 

Marushige, K., Dixon, G. H. Developmental changes in chromosomal composition and template activity during spermatogenesis in trout testis. Develop. Biol. 19, 397—414 (1969). 

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