Sulla biochimica della fermentazione citrica da parte dell'Aspergillus niger

Summary In a strain ofAsp. niger grown inBernhauer medium, succinic-dehydrogenase activity decreased and asparticglutamic transaminase activity remained practically constant, while citric acid accumulated in the medium.     

Ultrastruttura della calcificazione distrofica renale da sublimato

Summary Carrying on the researches on the biological process of calcium deposition, the role of the substructures in the precipitation of calcium salts in the loci of distrophic calcification of kidney tubules following sublimate injections has been investigated. In agreement with the histochemical data previously found, the presence of collagen fibres in these sites is excluded; the morphological appearance of crystal deposits is described. The importance of mitochondria in the calcium ion deposition in kidney tubules is discussed.     

Diabete da allossana

Summary Insulin deficiency induced by alloxan treatment reduces cocarboxylase activity in the liver of rat. Such enzymatic activity, however, is brought back to the normal speed by fructose injection. It is suggested that fructose, the turn-over of which in diabetic animals is normal, may be capable of furthering the synthesis of A.T.P. and enhancing phosphorylation of thiamine into cocarboxylase.

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Nota N^o 1; Rapporti fra utilizzatione del fruttosio ed attività cocarbossilasica.     

Sulla struttura microscopica dei cromosomi

Conclusioni Numerosissime osservazioni sulla struttura dei cromosomi in materiali diversissimi dimostrano concordemente che i cromatidi sono avvolti secondo un'elicoide.Questa disposizione spaziale ha un'importanza fondamentale nei processi di riproduzione e di trasformazione dei cromosomi («internal mechanics» diDarlington); ma, in molti particolari di importanza notevole, le opinioni dei citologi sono contrastanti.L'esame comparativo delle trasformazioni cromosomiche, sopratutto nella spermatogenesi e nell'oogenesi, che sono state qui esposte, ci permette di dare un'interpretazione generale sulla struttura cromatidica e sulla disposizione spaziale dei cromatidi nella mitosi e nella meiosi.I cromatidi sarebbero costantemente avvolti secondo un'elicoide «minor». Lo svolgimento di tale elicoide si osserverebbe soltanto in alcuni casi, ad es. nei nuclei degli oociti in accresimento. In questi sono visibili i veri cromomeri. I cromomeri comunemente descritti sarebbero invece giri dell'elicoide «minor», distribuiti irregolarmente lungo l'asse del cromosoma in relazione forse alla distribuzione dei veri cromomeri ed alle caratteristiche della matrice.La costanza dell'avvolgimento elicoidale «minor» ed il fatto che l'autoriproduzione cromatidica avviene nell'interfase, rendono molto verosimile che nei cromosomi a due o quattro cromatidi si formino sempre degli avvolgimenti paranemici. La stessa disposizione spaziale dei cromatidi si avrebbe in seguito all'appaiamento meiotico.Questo tipo di struttura nella maggior parte dei casi è confermato dalle trasformazioni cromosomiche, che precedono la separazione meta-anafasica dei cromosomi figli, ed è quella che probabilmente meglio concorda coi meccanismi di riproduzione cromosomica.

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Summary Very many observations of the structure of the chromosomes in various materials show, without exception, that the chromatids are coiled like springs.This spatial arrangements is of fundamental importance in processes of reproduction and changes in chromosomes (internal mechanics ofDarlington), but in many important particulars the opinions of cytologists differ.The comparative study of changes in chromosomes, especially during spermatogenesis and oögenesis, which are described here, permits us to give a general interpretation of the chromatid structure and of the spatial distribution of the chromatids in mitosis and meiosis.The chromatids should be constantly coiled in a minor spiral. The uncoiling of such spirals could be observed in some cases only, e.g., in nuclei of growing oöcytes. In this the chromomeres are visible. The chromomeres commonly described should be the coils of the minor spiral, distributed irregularly along the axis of the chromosomes, perhaps in relation to the distribution of true chromomeres and to the characteristics of the matrix.The constancy of the minor coil and the fact that chromatid reproduction takes place at the interphase, makes it very likely that in chromosomes with two or four chromatids there is always paranemic coil. The same spatial arrangement of the chromatids should have followed meiotic pairing.In most cases this type of structure is confirmed by the changes in the chromosomes, which precede the separation of the daughter chromosomes at meta-anaphase, and it is in better agreement with the mechanisms of chromosomes reproduction.

     

Sul meccanismo di azione della streptomicina

Summary A study was undertaken on the variations of the redox potential level produced by streptomycinin vitro andin vivo. We have been able to show that, owing to an oxidative effect, streptomycin produces an increase of the redox potential level. This oxidative effect varies in degree according to the condition of the patient.We also found that in the blood and in the spinal fluid of patients suffering from tubercular meningitis factors are present which inhibit the action of streptomycin.The results of our findings lead to the conclusion that the dose of streptomycin must be varied according to the condition of the patient if the constant level required for an efficient therapy is to be maintained in the blood and in the spinal fluid.     

La Rigenerazione del testicolo atrofico da Fluoroacetamide

Summary Morphological changes of atrophic testis, obtained by treating normal rats with fluoroacetamide, are studied at various times after treatment. The data show that the testicular germinal epithelium is fully regenerated 165 days after treatment.     

Degradation of chlorobenzoates byAspergillus niger

Summary InA. niger, the degradation of chlorobenzoates follows the protocatechuate branch of ß-ketoadipate pathway and the elimination of chloride takes place in the first hydroxylation step prior to ring cleavage.Acknowledgment. We wish to thank B.V. Kamath and Prof. Y.K. Agrawal for their help and advice in completing this investigation.     

Radiation-induced hyperdiploidy inHyoscyamus niger L

Summary A hyperdiploid plant type, approaching the triploid chromosome number, and representing possibly a high level of tetrasomy, was recorded in the progeny of a gamma ray-induced unbranched desynaptic mutant in the M₄ generation. Its meiotic behavior and its possible importance for deriving diverse hyperdiploid lines from desynaptic mutants are outlined.Acknowledgment. We are grateful to Dr Akhtar Hussian, Director, CIMAP, for his keen interest in the study and for providing the facilities.     

Repressible alkaline phosphotase inAspergillus niger

Summary ALP fromA. niger is a) P_i repressible enzyme; b) stimulated by addition of Zn⁺⁺ to the growth medium, and c) that EDTA inhibits the enzyme reversibly, which could be restored by addition of Zn⁺⁺ and perhaps Mg⁺⁺. This property is in contrast to the enzyme fromN. crassa, which is independent of any metal requirement.     

Partial complementation inAspergillus niger heterocaryon

Zusammenfassung Erzwungene Heterokaryen-Vereinigung zwischen Hypoxanthin und Histidin abhängiger Mutanten vonAspergillus niger, die auf minimalem Nährboden ohne Sporenproduktion wachsen. Das Phänomen wird als teilweise Ergänzung bezeichnet und als Gleichgewichtsstörung der Kerntypen im Heterokaryen oder als Verdünnungseffekt eines Genproduktes zweiter Ordnung im Zytoplasma gedeutet.     

Sul meccanismo della eptoformazione non ossidativa nel muscolo scheletrico

Summary F-1,6-P has been shown to increase the rate of non-oxydative heptoformation from glucose-6-phosphate and fructose-6-phosphate in enzymatic preparations of rat skeletal muscle. The mechanism of this increase — probably due to triose-phosphate, formed by aldolase action on F-1,6-P — is discussed.     

Sul meccanismo di azione della vaccinoterapia nella infezione tifoidea

Summary Having observed before that the blood serum of typhoid patients acquires under the stimulus of the vaccine an evident bacteriolytic action on the typhoid bacillus, we have studied variations brought about by the vaccine stimulus in the blood of the patients as to the redox-potential and to the glutathione in the blood.It has been seen that under vaccine stimulus there is a rapid increase of redox-potential and of the glutathione in the blood: lasting in the cases which tend to recovery, temporary in the cases in which the illness takes its natural course.The values of the total glutathione increase more than those of reduced glutathione, so that an increase of the values of the oxidized glutathione is found.The variations of the values of the redox-potential and of the oxidized glutathione brought about by the vaccine reaction in the blood of the patients leads us to consider the mechanism of the action of vaccine therapy in typhoid infection, on the same principle described by us regarding the action of penicillin.     

Inattivazione della gramicidina dovuta alla conversione triptofano → N'-Formilchinurenina

Summary Treatment of gramicidin with ozone in formic acid leads to a tryptophan-N'-formylkynurenine conversion. Such a conversion causes a decrease of both bacteriostatic and haemolytic activities.     

Nuovo tampone volatile da impiegarsi in cromatografia ed elettroforesi

Summary A volatile ethilendiamine-acetate buffer is described which is capable of keeping the pH unaltered during volatilization. The advantages of this buffer in electrophoretic and chromatographic procedures, in comparison with other volatile buffers, are discussed.     

L'azione protettiva dell'acido tioctico nell'intossicazione da cianuro di potassio

Summary The protective action of thioctic acid and of its reduced form in acute potassium cyanide poisoning has been studied in comparison with the antitoxic action of other compounds with mercapto or disulfide groups.The results permit the following conclusions: (1) Maximum protective action is given by reduced thioctic acid; (2) thioctic acid and BAL have almost the same activity; (3) cysteine and sodium thiosulfate have a protective activity of a much lower order; (4) panthethine is almost inactive. The authors offer the hypothesis that the greater activity of thioctic acid is due to its possible presence as coenzyme in rhodanese.     

Effetto della ouabaina sul tessuto nervoso in coltura in vitro

Summary The addition of 1 · 10^–4 ouabain (strophantin-G), a Na⁺-K⁺-dependent ATP-ase inhibitor, to the cultivating medium of chick embryo spinal ganglia in vitro cultures caused the vacuolization of the cytoplasm of the fibroblast-like cells, but not of the nervous ones, after 6 h of culture, with a maximum after 24 h.     

Proliferazioni iperplastiche e neoplastiche delle vie bilifere intraepatiche da tioacetamide

Summary Prolonged thioacetamide administration to albino rats causes in the liver marked proliferative phenomena, which begin in the portal tracts as relatively undifferentiated plasmodial cells. These later arrange themselves in solid or hollowed tubules, which are accompanied by reticular and collagen fibers, altering the normal structure of the liver. In some cases, bile duct—adenomata were evident.     

Lipid accumulation by a cellulolytic strain ofAspergillus niger

Lipid accumulation by a cellulolytic mold,Aspergillus niger, was studied. The amount of lipid accumulated ranged from 13.6–16.6% on various carbon sources, namely glucose, xylose, avicel (microcrystalline cellulose) and bagasse (a natural lignocellulosic substrate). Neutral lipids, phospholipids and glycolipids of the mycelia varied from 41.0–46.2%, 34.9–38.4% and 18.7–22.6% of total lipids, respectively. Unsaturated fatty acids comprised around 80% of total fatty materials with linoleic and oleic acid predominating. Of the four nitrogen sources tested, NH₄Cl was the best source for lipid synthesis from cellulose (bagasse). Optimum temperature range for growth and lipid synthesis was 25–30°C.