Semen Characteristics of Purebred and Crossbred Male Rabbits

The aim of this investigation was to evaluate the semen quality traits of purebred male rabbits and their crosses under subtropical Egyptian conditions. A full 3 x 3 diallel crossing was performed for producing the first generation progeny of New Zealand White (N), Flander (F) and Rex (R) breeds. The highest ejaculate volume (p< 0.05) and percentage of live sperms (p<0.01) with the lowest percentage of sperm cell morphological abnormalities (p<0.05) had been recorded in the NF bucks. Moreover, they possessed positive estimates of direct heterosis for ejaculate volume, mass motility (Mm), individual motility (Im) and sperm cell concentration (SCC). On the contrary, pH had negative estimates of direct heterosis in all crosses and their reciprocal. Semen pH was negatively correlated with SCC (r = -0.18), Mm (r = -0.13) and Im (r = -0.23). In conclusion, the superiority of crossbreeding was particularly obvious in the New Zealand White x Flander males, which cumulated heterosis and favorable maternal effects of the Flander dams.     

Hydrolysis ofγ-glutamyl linkages byFusobacterium nucleatum

The cell extracts of two human oral strains (FN2 and FN3) ofFusobacterium nucleatum displayed exceptionally high-glutamylpeptidase activity as determined withN--l-glutamyl-2-naphthylamine as substrate. This activity was so dominant that the hydrolysis of otherN-aminoacyl-2-naphthylamines progressed at a rate <10% of the former. Two major enzymes (I and II) were partially purified from FN2. I had a molecular weight of 115,000 and did not hydrolyze-glutamylcysteinylglycine (glutathione). II had a molecular weight of 70,000 and rapidly liberated only glutamic acid from glutathione. Strain FN3 contained several enzymes hydrolyzing-glu-2NA. Direct anion exchange chromatography of FN3 cell extracts separated one enzyme that liberated both glutamic acid and glycine from glutathione, one that was inactive against glutathione (but hydrolyzed-glu-2NA), and one that liberated only glutamic acid. Although-glu-2NA was a good synthetic substrate, glutathione was hydrolyzed at least 500 times faster by an enzyme present in both strains. These results indicate that the presence of-glutamylpeptidase activity is very characteristic of theseF. nucleatum strains.     

Effects of oleic acid on the biosynthesis of lipoprotein apoproteins and distribution into the very-low-density lipoprotein by the isolated perfused rat liver.

The effects of oleic acid on the biosynthesis and secretion of VLDL (very-low-density-lipoprotein) apoproteins and lipids were investigated in isolated perfused rat liver. Protein synthesis was measured by the incorporation of L-[4,5-3H]leucine into the VLDL apoproteins (d less than 1.006) and into apolipoproteins of the whole perfusate (d less than 1.21). Oleate did not affect incorporation of [3H]leucine into total-perfusate or hepatic protein. The infusion of oleate, however, increased the mass and radioactivity of the VLDL apoprotein in proportion to the concentration of oleate infused. Uptake of oleate was similar with livers from fed or fasted animals. Fasting itself (24 h) decreased the net secretion and incorporation of [3H]leucine into total VLDL apoprotein and decreased the output of VLDL protein by the liver. A linear relationship existed between the output of VLDL triacylglycerol (mumol/h per g of liver) and secretion and/or synthesis of VLDL protein. Net output of VLDL cholesterol and phospholipid also increased linearly with VLDL-triacylglycerol output. Oleate stimulated incorporation of [3H]leucine into VLDL apo (apolipoprotein) E and apo C by livers from fed animals, and into VLDL apo Bh, B1, E and C by livers from fasted rats. The incorporation of [3H]leucine into individual apolipoproteins of the total perfusate lipoprotein (d less than 1.210 ultracentrifugal fraction) was not changed significantly by oleate during perfusion of livers from fed rats, suggesting that the synthesis de novo of each apolipoprotein was not stimulated by oleate. This is in contrast with that observed with livers from fasted rats, in which the synthesis of the total-perfusate lipoprotein (d less than 1.210 fraction) apo B, E and C was apparently stimulated by oleate. The observations with livers from fed rats suggest redistribution of radioactive apolipoproteins to the VLDL during or after the process of secretion, rather than an increase of apoprotein synthesis de novo. It appears, however, that the biosynthesis of apo B1, Bh, E and C was stimulated by oleic acid in livers from fasted rats. Since the incorporations of [3H]leucine into the VLDL and total-perfusate apolipoproteins were increased in fasted-rat liver when the fatty acid was infused, part of the apparent stimulated synthesis of the VLDL apoprotein may be in response to the increased formation and secretion of VLDL lipid.     

Primary production and respiration of the phytoplankton in the Blue and White Niles at Khartoum

Phytoplankton production and respiration in the Blue Nile and White Nile at Khartoum were measured during the period November 1969–January 1971 using the light and dark bottle technique. Maximum rates of production coincided with periods of maximum phytoplankton densities. In the Blue Nile gross production varied between 0.00 gCm^–3d^–1 during the flood season and 2.19 gCm^–3d^–1 (0.49 mgO₂l^–1h^–1) during November 1969. In the White Nile the range was from 0.41 gCm^–3d^–1 (0.09 MgO₂l^–1h^–1) in May to 3.74 gCm^–3d^–1 (0.83 MgO₂l^–1h^–1) in November. The maximum rates of respiration in the Blue Nile and White Nile were 0.10 and 0.63 MgO₂l^–1h^–1 respectively. The ratios net:gross production were generally higher in the White Nile than in the Blue Nile.     

Correlation of tumor specific delayed type hypersensitivity reaction and tumor protection to SV40-induced mKSA fibrosarcoma

Summary Mice immunized by excision of a primary, subcutaneously growing SV₄₀-induced mKSA solid tumor which resisted challenge of homologous tumor cells administered at a contralateral site, were found to develop a specific DTH response to SV₄₀ tumor associated transplantation antigens (TATA).In a two-way criss-cross experiment, this DTH response (assessed by direct challenge) was found to be one-way SV₄₀ specific in that chemically induced, non SV₄₀, MCA tumor failed to elicit a DTH response in mice primed by excision of mKSA tumor.These mice also showed a corresponding one-way specific protection against challenge with live homologous mKSA sarcoma cells. In contrast immunization and challenge of MCA-excised mice with either MCA or mKSA tumor cells, exhibited cross-reactivity in both DTH response and protection against either tumor.Unlike this cross-immunity by the direct challenge method, transfer of immune spleen cells from mKSA or MCA excision-primed mice demonstrated a specific DTH response and protection to the original immunizing, homologous but not heterologous tumor. Tumor resistant, DTH-primed mice remained DTH reactive to the primary tumor cells over a period of 4 weeks. Characterization of the splenic T-DTH cells in mice primed by excision of mKSA tumor, indicated a Lyt 1⁺2⁺ phenotype of cells conferring both the DTH response and the immune protection against mKSA sarcoma in a local (Winn) adoptive transfer assay, thus reinforcing the correlation between the DTH response and the antitumor protection.     

A survey of histoplasmosis and blastomycosis in U.A.R. (Egyptian sector) a preliminary report

Summary A selected group of 525 individuals with pulmonary diseases, granulomas and other medical conditions was tested for histoplasmin and blastomycin dermal reactions. No positive results were observed. Few doubtful positive reactions were recorded (3 to histoplasmin and 7 to blastomycin). None of the patients with chronic cutaneous granulomas exhibited any reaction.Although the number of subjects studied is small, these preliminry findings suggest the probable absence of histoplasmosis and blastomycosis in Egypt.     

Observations on the venous system of three species of Polypterus (Pisces)

The venous system of Polypterus exhibits general asymmetry. The features that characterize the venous system of this peculiarly African fish are the possession of many blood sinuses, the segmental drainage of blood, the continuation of the posterior cardinal veins as separated vessels and the occurrence of several anastomozes between the latter.
In the absence of any recent comprehensive work on the blood system of this fish, it was thought that investigation of the circulatory system of Polypterus would be valuable. In this paper attention is drawn to Budgettapos;s (1902) original work on a larva of Polypterus senegalus. Contrary to Budgettapos;s findings it is concluded that what he called the "interrenal" vein is in fact the right posterior cardinal vein. It is also found that paired posterior cardinal veins exist in all adults.     

Quantitative analysis of the combined effects of temperature, evaporative demand and light on leaf elongation rate in well-watered field and laboratory-grown maize plants

The respective effects of meristem temperature, vapour pressuredeficit (VPD) and photosynthetic photon flux density (PPFD)on leaf elongation rate (LER) of maize, in the absence of waterdeficit in the soil have been quantified. This analysis wascarried out in a series of field experiments in northern andsouthern France over several seasons and years, and in growthchamber experiments. LER was measured with 10 min steps, togetherwith meristem temperature, VPD and PPFD at leaf level in threetypes of experiments: in growth chamber experiments with stepsin PPFD or VPD at constant meristem temperature, in growth chamberexperiments with several combinations of constant, but contrasting,PPFDs, VPDs and meristem temperatures, and in the field withfluctuating conditions, (i) When evaporative demand was low(night or day with low air VPD), LER was only linked to meristemtemperature, regardless of other climatic conditions, (ii) Lighthad no effect per se on LER in the range from 0 to 1500 molm^–2 s^–1 for time-scales longer than 2 h, providedthat its indirect effects on meristem temperature and on evaporativedemand were corrected (in the growth chamber) or taken intoaccount (in the field), and provided that cumulated PPFD overa weekly time-scale was compatible with field conditions, (iii)Evaporative demand sensed by growing leaves, as estimated bymeristem-to-air vapour pressure difference, markedly affectedLER in the range from 1–4 kPa, at all time-scales understudy, with a unique relationship in the growth chamber (constantconditions) and in the field (fluctuating conditions). Thiseffect was only observed when PPFD was high enough for stomatato open. The negative effect of evaporative demand on LER wasprobably not due to long distance root-to-shoot signalling,since soil was wet, calculated root water potential remainedclose to 0 MPa and concentration of ABA in the xylem sap wasvery low. Therefore, it is proposed to model maize LER witha two-step process, involving the calculation of the maximumLER at a given meristem temperature and then the calculationof the reduction in LER due to evaporative demand. Joint analysisof the whole set of data by using the two equations yieldeda r² of 0.75. This two-step process would be more accurate thanthe provision of LER from temperature only in cases where airVPD frequently exceeds 2 kPa. Key words: Leaf growth, light, evaporative demand, temperature, thermal time, water deficit, ABA, Zea mays L.     

Genetic analysis of agronomic traits in a cross between sugarcane (Saccharum officinarum L.) and its presumed progenitor (S. robustum Brandes & Jesw. ex Grassl)

Saccharum robustum Brandes & Jesw. ex Grassl has been suggested as the immediate progenitor species of cultivated sugarcane (S. officinarum L.) [4]. Chromosome pairing and assortment in these two species were previously studied by genetic analysis of single-dose DNA markers in parents in and 44 F₁ progeny of a cross between euploid, meiotically regular 2n=80S. officinarum LA Purple andS. robustum Mol 5829 [2]. This same population was subsequently clonally propagated and evaluated in replicated trials for quantitative traits important to sugarcane breeders. Numbers of stalks, tasseled stalks, and stalks with smut, and the average diameter of two stalks were determined one day prior to harvest. At harvest, plant material from each plot was weighed and evaluated for pol (sucrose content) and fiber percentages. Clones were significantly different (P<0.01) for all traits analyzed. Associations of 83 single-dose arbitrarily primed PCR genetic markers with quantitative trait loci (QTL) of recorded traits was determined by single-factor ANOVA, and multiple regression. QTL analysis revealed markers significantly (P<0.05) associated with the expression of each trait analyzed. Markers associated with QTL after multiple regression were tested for digenic linear × linear epistatic interactions. The various multilocus models explained between 23% and 58% of the total phenotypic variation and 32% and 76% of the genotypic variation for the various traits. Digenic interactions were uncommon. Implications for marker-assisted selection in sugarcane and sugarcane domestication are discussed.