Recognition of 29 kDa surface-associated adhesive molecule of Entamoeba histolytica by monoclonal antibodies

Abstract Monoclonal antibodies have been developed and used as specific probe to locate and identify a 29-kDa molecule of axenic Entamoeba histolytica trophozoites. Monoclonal antibody produced by clone C8 (MoAb C8) strongly agglutinated the amoebic trophozoites. THe immunofluorescence of live E. histolytica trophozoites and surface fluorescence of acetone-fixed trophozoites by MoAb C8 indicated existence of a 29-kDa molecule on surface-associated plasma membrane of E. histolytica . The monoclonal antibody belonged to IgG₁ isotype. The prior treatment of E. histolytica trophozoites with MoAb C8 resulted in significant ( P < 0.01) reduction in adherence of amoebic trophozoites to cultured Chinese Hamster Ovary cells and significant ( P < 0.01) reduction in cytotoxicity to cultured Baby Hamster Kidney cells. Pretreatment of amoebic trophozoites with MoAb C8 prior to cultivation in TPS-1 medium resulted in significant ( P < 0.01) reduction in growth of the parasite. Thus, the data suggested that the surface-exposed 29-kDa molecule may be one of the receptors involved in E. histolytica host cell interactions and may possibly modulate amoebic disease processes.     

White Spot Syndrome Virus infection in Penaeus monodon is facilitated by housekeeping molecules

White Spot Syndrome Virus (WSSV) is a major pathogen in shrimp aquaculture, and its rampant spread has resulted in great economic loss. Identification of host cellular proteins interacting with WSSV will help in unravelling the repertoire of host proteins involved in WSSV infection. In this study, we have employed one-dimensional and two-dimension virus overlay protein binding assay (VOPBA) followed by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) to identify the host proteins of Penaeus monodon that could interact with WSSV. The VOPBA results suggest that WSSV interacted with housekeeping proteins such as heat shock protein 70, ATP synthase subunit β, phosphopyruvate hydratase, allergen Pen m 2, glyceraldehyde-3-phosphate dehydrogenase, sarcoplasmic calcium-binding protein, actin and 14-3-3-like protein. Our findings suggest that WSSV exploits an array of housekeeping proteins for its transmission and propagation in P. monodon.     

Phagocytosis of Plasmodium chabaudi: modulation by immune serum and antigen in vitro

The phagocytosis of free Plasmodium chabaudi parasite by resident peritoneal macrophages of mouse was studied in an in vitro system. The effect of antimalarial antiserum (HIS) was assessed by preincubation of parasite macrophages and both parasite and macrophages with HIS prior to use in phagocytic assays. Highest phagocytic index was obtained with HIS pretreated parasites. The two activities viz. opsonic (parasite dependent) and cytophilic (macrophage dependent) were noted to operate independent of each other. The phagocytosis promoting activity was found to be complement dependent. The receptor site for binding of HIS opsonized but not medium opsonized parasite on the surface of macrophages was blocked by pretreatment of these cells with HIS-soluble antigen combination.     

Determining relative abundance of specific DNA sequences in flow cytometrically sorted maize nuclei

A wide breadth of DNA content variation has been reported amongmaize lines. While the extent of this variation has been welldocumented, few studies have focused on its cause. Some of thenuclear DNA content variation has been explained by the presenceof B chromosomes or knobs. However, variation in these two structuresdoes not account for all of the observed variation. In orderto identify other fluctuating DNA sequences, a rapid and reliablemethod of estimating relative abundance of DNA sequences neededto be developed. The potential of flow cytometry in conjunctionwith spot hybridization for determining relative abundance ofspecific DNA sequences in maize was studied. Different numbersof G1 phase nuclei were sorted on nitrocellulose filters andnon-radioactive hybridization and signal detection performed.Results from these experiments revealed a significant, positivelinear correlation between the amount of target sequence andsignal density using both knob (R = 0.98) and ribosomal spacer(R =0.99) DNA sequences. In addition, G1 phase nuclei of eightinbred lines differing in the amount of knob heterochromatin,were sorted on to filters and the non-radioactive hybridizationand signal detection performed. A significant, positive linearcorrelation between C-band number and signal density (R =0.83;P = 0.0051) as well as between per cent heterochromatin andsignal density (R=0.96;P = 0.0002) was observed. These resultsindicate the usefulness of flow cytometry for spot hybridizationin determining the relative abundance of DNA sequences in themaize genome. Key words: Flow cytometry, copy number, non-isotope labelling, spot hybridization, flow sorting, Zea mays L.     

Immunobiological studies with mycobacterial ribonucleic acid-protein complex: Part II--Mechanism of protective immunity against experimental tuberculosis.

Passive transfer of protective antituberculous immunity against LD50 dose of M. tuberculosis H37Rv was found to be mainly mediated by immune T-cells harvested from spleens of donor mice immunized with Myc. RNA-P-FIA complexes as monitored by indices of percent survival, root specific lung weight, lung density and by bacterial enumeration from different organs. Treatment of immune T-cells with anti-Thy 1.2. monoclonal antibodies plus complement prior to passive transfer, completely abrogated its protective effect thereby confirming their protective nature. Passive transfer of immune sera as well as immune T + B cells did not induce any enhancement in protective immunity.     

Steroid synthesizing cellular sites in the ovary of the domestic pigeon Columba livia (Gmelin): a histochemical study.

Synopsis The ovary of the domestic pigeon,Columba livia, has been assayed histochemically for the localization of ⁵-3-hydroxysteroid dehydrogenase (⁵-3-HSDH), 17-hydroxysteroid dehydrogenase (17-HSDH), 11-hydroxysteroid dehydrogenase (11-HSDH), glucose-6-phosphate dehydrogenase (G6P-DH) and NADH-diaphorase activities during different periods of the reproductive cycle. ⁵-3-HSDH, 17-HSDH, 11-HSDH, G6P-DH and NADH-diaphorase activity was found in the theca interna of growing, atretic and postovulatory follicles, the granulosa of ovulatory, atretic and postovulatory follicles, and interstitial gland cells during the pre-incubation and the laying periods. During the incubation and squab feeding periods only ⁵-3-HSDH, G6P-DH and NADH-diaphorase activities were observed in the above mentioned cells. The steroidogenic potential of atretic follicles depends upon the type of atresia a follicle undergoes.     

Bromoacetylcholine as an affinity label of the acetylcholine receptor from Torpedo californica

Bromoacetyl[methyl-³H]choline is a highly specific label for the reduced acetylcholine binding site on the acetylcholine receptor from $\text{Torpedo californica}$. Only one of two binding sites per receptor monomer is susceptible to labeling. The labeled site is on the α chain of the receptor.     

Gut-associated immune effector responses in immunocompetent and immunocomprimised mice with Giardia lamblia

Abstract Significantly higher Giardia lamblia trophozoites load in the intestine of infected mice accompanied pronounced influx of suppressor/cytotoxic T cells (Lyt 2.2⁺), T cells (Thy 1.2⁺) and significant reduction in IgA-containing cells in the gut during the establishment and peak phases of infection. The induction of helper/inducer T cells (Lyt 1.1⁺) and significant enhancement of IgA-containing cells in gut resulted in the decline of the trophozoite loads. However, the prior treatment of animals with dexamethasone alone resulted in significant reduction in helper/inducer T cells (Lyt 1.1⁺) and the IgA-containing cells in the gut; the percents of suppressor/cytotoxic T cells (Lyt 2.2⁺) and IgM-containing cells remained unaltered. Although the G. lamblia infection in such animals further significantly increased the influx of suppressor/cytotoxic T cells, the late response of helper/inducer T cells and IgA-containing cells was abrogated during the decline phase of infection. The significant reduction in the trophozoite load — despite immuno-suppressive therapy — appeared to be due to unaltered IgM response in such animals which probably took over the function of IgA in defense against G. lamblia . The data of the investigation thus suggested a role of helper/inducer T cells and antibodies producing cells in gut as important effector cells resulting in the termination of primary G. lamblia infection.     

Superior Oxygen Reduction Reaction on Phosphorus‐Doped Carbon Dot/Graphene Aerogel for All‐Solid‐State Flexible Al–Air Batteries

Carbon dots have been recognized as one of the most promising candidates for the oxygen reduction reaction (ORR) in alkaline media. However, the desired ORR performance in metal–air batteries is often limited by the moderate electrocatalytic activity and the lack of a method to realize good dispersion. To address these issues, herein a biomass‐deriving method is reported to achieve the in situ phosphorus doping (P‐doping) of carbon dots and their simultaneous decoration onto graphene matrix. The resultant product, namely P‐doped carbon dot/graphene (P‐CD/G) nanocomposites, can reach an ultrahigh P‐doping level for carbon nanomaterials. The P‐CD/G nanocomposites are found to exhibit excellent ORR activity, which is highly comparable to the commercial Pt/C catalysts. When used as the cathode materials for a primary liquid Al–air battery, the device shows an impressive power density of 157.3 mW cm^?2 (comparing to 151.5 mW cm^?2 of a similar Pt/C battery). Finally, an all‐solid‐state flexible Al–air battery is designed and fabricated based on our new nanocomposites. The device exhibits a stable discharge voltage of ≈1.2 V upon different bending states. This study introduces a unique biomass‐derived material system to replace the noble metal catalysts for future portable and wearable electronic devices.