Identification of small nuclear DNA molecules of the cuban sugarcane cultivar Ja60-5 via pulsed field gel electrophoresis

We present evidence of the existence of at least 7 small nuclear DNA molecules in the Ja60-5 sugarcane cultivar genome. These small molecules were separated by means of transversal alternating field electrophoresis (TAFE); their sizes ranged from about 230–3000 kbp, and they hybridized with telomeric, subcentromeric, and various nuclear DNA probes. Here, we also report the use and the modifications of DNA from microorganisms, to immobilize nuclear DNA from sugarcane suitable for analysis via pulsed field gel electrophoresis. The protocol is simple, inexpensive, and easy to perform.     

Effect of medium composition on the ultrastructure of Lactobacillus strains

The growth of some locally isolated Lactobacillus strains forming D(-) or L(+) lactic acid, Lactobacillus helveticus ATCC 15009 and Lactobacillus delbrueckii subsp. bulgaricus ATCC 11842 was examined in different media. L. helveticus and Lactobacillus LBL strains formed atypical protoplast-like cells in LAPT medium, sensitive to SDS and proteinase. Specific morphological changes in the cell wall structure of these variants were revealed by transmission and scanning electron microscopy. The effect of glucose and various salts on their appearance was investigated. The prevalent role of metal cations, especially of Mg²⁺, was established.     

The rate limiting step in the reticulocyte uptake of transferin and transferrin iron Effects of some incubation variables

Reticulocytes incubated in an isotonic NaCl saline medium containing glucose, glutamine and amino acids, were able to detach both iron atoms from all the transferrin incorporated by them. In the absence of these metabolites, although transferrin uptake was the same, the reticuloctes failed to remove completely the iron from the transferrin which they incorporated.It has been shown before that there is unspecific as well as specific binding of transferrin to the reticulocyte. By incubating the cells in the presence of a high concentration of bovine serum albumin, we have been able to prevent the unspecific attachment of transferrin.At least 94% of the iodinated transferrin was capable of donating its iron to the reticulocytes.     

Rate of concentration and digestion of radioactive growth hormone preparations injected in rats,as measured by the amount and nature of radioactivity in the tissues

Summary The distribution of radioactivity in the tissues of the rat has been established after the administration of radioactive bovine growth hormone preparations.Bovine growth hormone was used either transformed in to a¹⁴C-guanidinated derivative, which was fully active, of labeled with less than 1 mole per mole of¹²⁵I.The tissue radioactivity distribution curves obtained belong to two different categories: in kidney, liver and spleen there is an early concentration which attains a maximum in 15 minutes after the injection of the hormone, and rapidly declines. In heart, skeletal muscle, pancreas, intestine, bone and fat, the radioactivity increases gradually and a steady-state is reached after 30 to 60 minutes.Kidney is the organ where the highest concentration of radioactivity occurs. However, muscle accumulates more than 60% of the initial doses after 2 hours. Very little radioactivity appears in the urine, in this period.Similar results have been obtained with pharmacological or physiological doses of the labeled hormones.Blood plasma does not degrade the injected hormone but kidney, liver and muscle rapidly produce radioactive fragments soluble in 10% trichloro-acetic acid.Dedicated to ProfessorLuis F. Leloir on the occasion of his 70^th birthday.     

Effect of photoperiod on characteristics of semen obtained by electroejaculation in stump-tailed macaques (Macaca arctoides)

Some environmental variables determining seasonal reproduction in mammals are temperature, humidity, food availability, and photoperiod. Among these, photoperiod is considered the main regulator of primates’ seasonal reproduction, thus the latitudinal distribution of primate populations is a key factor determining the appearance of seasonal reproduction. The present work presents supporting discrete seasonality in male stump-tailed macaques (Macaca arctoides). We investigated whether semen quality and testosterone covaried with Mexico City’s photoperiod and relative humidity by analyzing variations in the portions that form the ejaculate: the seminal liquid, the seminal coagulum, and the copulatory plug. Five male adult stump-tailed macaques were electroejaculated once a month, obtaining three semen samples per male, from August 2011 to July 2012 (except for December 2011) (n = 165). Our results showed that stump-tailed macaque sperm counts were significantly different between the portions of the ejaculate. The seminal coagulum contained the significantly largest number of spermatozoids, followed by the copulatory plug and the seminal fluid. Photoperiod and relative humidity had major influence on the sperm count in the seminal coagulum and the testosterone concentrations. Testosterone reached its highest values around the time when days and nights lasted the same hours, decreasing when days either grew longer or became shorter. Concerning relative humidity, sperm counts in the seminal coagulum were highly variable on dry days, but decreased as the relative humidity increased. We conclude that stump-tailed macaques have a discrete seasonality, occurring in spring and fall when macaques’ reproductive condition and readiness for postcopulatory intrasexual competition increase.     

Cell wall invertases from apex and callus tissues of sugar cane

Calluses were obtained from the stalk apex of sugar cane. Boththe stalk apex and callus tissues possessed firmly bound cellwall invertases. The invertases of each tissue were characterizedon the basis of their Km, optimum pH and the action of variousinhibitors. According to this characterization, the two tissuespossess different isoenzymes. Taking into account the presentisoenzymes and the known cell wall invertases from stalk tissue,we postulated a different pattern of isoenzymes for each organof the sugar cane. These differences suggest that the cell wallinvertases might be used as markers in studies of tissue differentiation. (Received May 27, 1980; )     

Prediction of antiviral peptides derived from viral fusion proteins potentially active against herpes simplex and influenza A viruses

There are very few antiviral drugs available to fight viral infections and the appearance of viral strains resistant to these antivirals is not a rare event. Hence, the design of new antiviral drugs is important. We describe the prediction of peptides with antiviral activity (AVP) derived from the viral glycoproteins involved in the entrance of herpes simplex (HSV) and influenza A viruses into their host cells. It is known, that during this event viral glycoproteins suffer several conformational changes due to protein-protein interactions, which lead to membrane fusion between the viral envelope and the cellular membrane. Our hypothesis is that AVPs can be derived from these viral glycoproteins, specifically from regions highly conserved in amino acid sequences, which at the same time have the physicochemical properties of being highly exposed (antigenic), hydrophilic, flexible, and charged, since these properties are important for protein-protein interactions. For that, we separately analyzed the HSV glycoprotein H and B, and influenza A viruses hemagglutinin (HA), using several bioinformatics tools. A set of multiple alignments was carried out, to find the most conserved regions in the amino acid sequences. Then, the physicochemical properties indicated above were analyzed. We predicted several peptides 12-20 amino acid length which by docking analysis were able to interact with the fusion viral glycoproteins and thus may prevent conformational changes in them, blocking the viral infection. Our strategy to design AVPs seems to be very promising since the peptides were synthetized and their antiviral activities have produced very encouraging results.