Quadriacanthus aegypticus n. sp., a monogenean gill parasite from the Egyptian teleost Clarias lazera

Summary Quadriacanthus aegypticus n. sp., a monogenean from the gills of Clarias lazera inhabiting Nile delta waters in Egypt, is described. The genus Quadriacanthus Paperna, 1961 is reported for the first time in Egypt. Particular attention has been paid to the reproductive system, the digestive system, the anterior adhesive glands, the posterior body glands and haptoral sclerites. Possible functions of the different internal organs are discussed. The diagnosis of the genus Quadriacanthus is emended. ac]19840926     

Physiology and characterization of a fungal milk-clotting enzyme from Aspergillus flavus.

Aspergillus flavus produced extracellularly an active rennin-like enzyme when grown aerobically in whey media. The enzyme was detected at early stages of growth reaching a maximum after three to four days at 25 degrees. The activity was destroyed by heating to temperatures higher than 50 degrees, whereas the presence of skim milk during heating preserved the enzyme activity, at least, up to 70 degrees. Calcium chloride significantly stimulated the milk-clotting activity up to 1% final concentration. The clotting time was inversely proportional to protein concentration in the range 0.2-0.6 mg/ml and the enzyme exhibited marked stability when stored at 37 degrees at pH 6.     

Anthropological studies among Libyans. Erythrocyte genetic factors,serum haptoglobin phenotypes and anthropometry

Anthropological studies were done on 1276 Libyans from the Mediterranean cities of Tripoli and Benghazi, and from Sabha southward in The Sahara. The incidences of hemoglobin (Hb)-S and glucose-6-phosphate dehydrogenase (G-6-PD) deficiency were low in the coastal areas and significantly high in Sabha. Hb-C occurred sporadically in Tripoli and Sabha, and was absent from Benghazi in the east. One case of Hb-J Benghazi was noted. There were no significant differences in the ABO blood group and Rh₀ (D) type distributions in the three localities. G-6-PD gene Gd^A frequency was significantly high in Sabha. The lowest value of 6-phosphogluconate dehydrogenase (6-PGD) gene PGD^A frequency and highest value of the gene PGD^C were in Sabha. Adenylate kinase (AK) gene AK² was only detectable in Tripoli. Acid phosphatase (AP) gene P^a frequency in Sabha was more than twice that in Tripoli and Benghazi, while P^c was distinctly lower in Sabha than in the northern cities. Haptoglobin gene Hp¹ frequency was almost identical in all areas. Anthropometric measurements revealed overall homogeneity of the three samples, closer similarity in the coastal region to adjacent North African populations, and Negroid influence in the Saharan Libyans. Anthropometry substantiated findings from blood markers.     

Evaluation of in vitro antibacterial activity of some disinfectants on Escherichia coli serotypes

Three disinfectants commonly used in poultry farms (formalin, TH4+, and Virkon-S) were chosen for the present study. The effect of disinfectant concentration and the duration of exposure to these disinfectants on the survival of Escherichia coli serotypes (O114:K-, O86, O55:K39, and O86:K60) were investigated. Formalin (0.6%), TH4+ (0.06%), and Virkon (0.5%) all killed the four serotypes within 5 min of exposure. As the disinfectant concentration decreases, the length of exposure time to kill serotype increases. At 0.03%, 0.007%, and 0.03% of formalin, TH4+ and Virkon-S concentrations failed to kill the four E. coli serotypes within 360 min, respectively. An improvement of the inhibitory effect of these disinfectants occurred when added together with the inoculum instead of an established population. The influence of formalin, TH4+, and Virkon-S on the cell morphology of E. coli O55:K39 was investigated by using transmission electron microscopy. Formalin-treated cells exhibited normal cell morphology, with the exception that the treated cell was less fimbriated, and more destruction of pili increased when formalin concentrations were doubled. Cells treated with TH4+ (0.03%) showed destruction of the cell wall and cell surface membrane after 5 min. Cell filamentation occurred at 0.015% and increased with the increase of exposure time to this drug. Spheroplasts were observed only when cells were treated with 0.125% Virkon-S for 60 min, and cell lysis started to occur when 0.25% Virkon-S was applied for 15 min. Scanning electron microscope study revealed that Virkon-S at 0.03% and TH4+ at 0.007% completely prevented the adherence of E. coli O55:K39 serotype to chicken tracheal organ, whereas formalin (0.03%) disinfection minimized the adherence of E. coli cells to tracheal explants after 360 min of incubation.     

Expression of LEKTI domains 6-9' in the baculovirus expression system: recombinant LEKTI domains 6-9' inhibit trypsin and subtilisin A

The precursor lympho-epithelial Kazal-type-related inhibitor (LEKTI), containing two Kazal-type and 13 nonKazal-type domains, is an efficient inhibitor of multiple serine proteinases, among them plasmin, subtilisin A, cathepsin G, elastase, and trypsin. To gain insight into the structure and function of some of these domains, a portion of the cDNA coding for LEKTI domains 6-9' was cloned and expressed in Sf9 cells using the baculovirus expression vector system (BEVS). Through a single purification step using a Co2+ column, 3-4 mg of purified recombinant LEKTI-domains 6-9' (rLEKTI6-9') with the predicted molecular mass of 34.6 kDa was obtained from the cell pellet of a 1-L culture. Unlike full-length LEKTI, rLEKTI6-9' inhibited trypsin and subtilisin A but not plasmin, cathepsin G, or elastase. The inhibition of trypsin and subtilisin A by rLEKTI6-9' occurred through a noncompetitive mechanism, with inhibitory constants (Ki) of 356 +/- 12 and 193 +/- 10 nM, respectively. On the basis of the Ki values, rLEKTI6-9' was determined to be a more potent trypsin inhibitor and a less potent subtilisin A inhibitor than the full-length LEKTI. In contrast to LEKTI domains 6-9', recombinant LEKTI domain 6 does not inhibit subtilisin A but competitively inhibited trypsin with a Ki of 200 +/- 10 nM. Taking LEKTI6-9' as an example, the BEVS should facilitate the structure-function analysis of naturally occurring processed LEKTI forms that have physiological relevance.     

Identification of 100 KDa protein in sera of mice-treated with Cu(II) complex with superoxide dismutase-mimetic activity

The protein profile of sera isolated from mice pre-treated with Cu(II) complex of Girard T with superoxide dismutase (SOD)-mimetic activity was analyzed using SDS-PAGE. This complex was intraperitoneally administered (10 mg/Kg body weight) to Swiss albino mice. The resolved polypeptides showed a new sharp band at 100 KDa against which a polyclonal antibody was raised in rabbit. Sera of rabbit anti-100 KDa protein was used as a powerful probe for the detection of 100 KDa protein isolated from sera of treated mice. Western blot assays revealed a strong reactive polypeptide band at 100 KDa in sera of the mice, but no cross reaction was observed with sera of normal mice. The identification of purified polypeptide was confirmed by different characterization experiments.     

Intraspecific variation in the venom of the vermivorous cone snail Conus vexillum

A combination of proteomic and biochemical assays was used to examine variations in the venom of Conus vexillum taken from two locations (Hurgada and Sharm El-Shaikh) in the Red Sea, Egypt. Using MALDI/TOF-MS, a remarkable degree of intra-species variation between venom samples from both locations was identified. To evaluate variability in the cytotoxic effects of Conus venom, mice were injected with the same dose from each location. The oxidative stress biomarkers [malondialdehyde (MDA), protein carbonyl content (PCC)], antioxidants [glutathione (GSH), superoxide dismutase (SOD), catalase (CAT)], total antioxidant capacity (TAC) and nitric oxide (NO), were measured 3, 6, 9 and 12 h post venom injection. The venoms induced a significant increase in the levels of PCC, MDA, NO, GSH and CAT. The venoms significantly inhibited the activity of SOD and reduced the TAC. Toxicological data showed that the venom obtained from Hurgada was more potent than that obtained from Sharm El-Shaikh. It can be concluded that: (1) the venom of the same Conus species from different regions is highly diversified (2) the venoms from different locations reflect clear differences in venom potency and (3) the cytotoxic effects of C. vexillum venom can be attributed to its ability to induce oxidative stress.     

Cyclophosphamide induces bone marrow to yield higher numbers of precursor dendritic cells in vitro capable of functional antigen presentation to T cells in vivo

We have shown recently that cyclophosphamide (CTX) treatment induced a marked increase in the numbers of immature dendritic cells (DCs) in blood, coinciding with enhanced antigen-specific responses of the adoptively transferred CD8⁺ T cells. Because this DC expansion was preceded by DC proliferation in bone marrow (BM), we tested whether BM post CTX treatment can generate higher numbers of functional DCs. BM was harvested three days after treatment of C57BL/6 mice with PBS or CTX and cultured with GM-CSF/IL-4 in vitro. Compared with control, BM from CTX-treated mice showed faster generation and yielded higher numbers of DCs with superior activation in response to toll-like receptor (TLR) agonists. Vaccination with peptide-pulsed DCs generated from BM from CTX-treated mice induced comparable adjuvant effects to those induced by control DCs. Taken together, post CTX BM harbors higher numbers of DC precursors capable of differentiating into functional DCs, which be targeted to create host microenvironment riches in activated DCs upon treatment with TLR agonists.