Volume 15, Issue 6
June 1942, pages 263-297
pp 263-277 June 1942
The testis structure of the two genera described here shows that it conforms to the plan outlined forIchthyophis glutinosus andUrœotyphlus narayani except that inDermophis gregorii very few testis lobes were seen. The testis locules are smaller inSiphonops annulatus when compared with those of the other three genera. The locules are filled with a matrix which inIchthyophis andUrœotyphlus were determined as containing fat. In this matrix are embedded the germ cells in groups in different stages of spermatogenesis. The primary spermatogonia are found at the mouth of the duct in the locule and are believed to have arisen, as inIchthyophis, from the cells lining the duct epithelium. Their nuclei may be spherical or polymorphic, the latter condition indicating a high degree of metabolic activity. Just before division, however, the nucleus resumes its spherical or oval contour. After a number of divisions, varying between six and eight, the cells,—now primary spermatocytes,—embark on the meiotic phase after a brief period of rest. The leptote ne and pachy tene stages follow, after which, the nucleus is marked by a ‘diffuse’ condition in which the chromosome bivalents lose their identity temporarily and the whole nucleus presents the appearance of a resting stage. When the bivalents emerge from this network, their chiasmata are clear and in the larger bivalents they are quite large in number though they are probably reduced later as inIchthyophis andUrœotyphlus. After a brief interkinesis the second division occurs giving rise to the spermatids.
pp 278-279 June 1942
pp 280-284 June 1942
Analysis of the edible portion of the badami and raspuri varieties of the mango fruit grown in Mysore has been made during the different stage of its development, with a view to finding out the change in moisture content, ash, pH, titratable acidity, the reducing sugars and sucrose.
The values obtained are tabulated to show the differences between the two varieties at different stages. It is particularly of interest to note that the badami variety contains a greater percentage of minerals and less of the sugars than the raspuri.
pp 285-297 June 1942
A study has been made of the rate of liberation of cystine and amino nitrogen from eight proteins during successive digestion by pepsin and trypsin.
Assuming the specificity of the Sullivan reaction it can be concluded that no free cystine is present in peptic digests.
The same reaction shows that cystine is rapidly set free during the action of trypsin. From the vegetable proteins (edestin, gliadin, anacardein and watermelon globulin) cystine is liberated much more rapidly than other amino-acids, practically the whole of the cystine in the protein being present in the free condition at a very early stage of proteolysis. Such complete liberation does not take place with the animal proteins (serum globulin, egg albumin and fibrin) ; with these, rate of cystine splitting approximates more closely to peptide hydrolysis. In the course of tryptic digestion at alkaline pH destruction of cystine takes place, the extent of the destruction varying from protein to protein.
The Folin and Marenzi reagent gives high colour values with both peptic and tryptic digests. These values have no relation to the free cystine present, being frequently in great excess of the total cystine content of the protein. This colour production is due to cystine complexes and not to non-nitrogenous substances as has been previously suggested.