Idiopathic scrotal calcinosis: a non-elucidated pathogenesis and its surgical treatment

Scrotal calcinosis (SC) is a rare, benign entity defined as the presence of multiple calcified nodules within the scrotal skin. In most cases, there are no associated symptoms. We report the case of 27-year-old man with a massive SC. Treatment was surgical with complete excision of the affected part of the scrotum wall. Histopathologically, there was no epithelial lining around the calcified nodules and no cystic structure. Therefore, our case was considered idiopathic SC.     

Boromorphus saudicus sp. n., a new record of the genus from the Arabian Peninsula (Tenebrionidae: Pimeliinae: Boromorphini)

Boromophus saudicus sp. n. (subfamily Pimeliinae Latreille, 1802, tribe Boromorphini Skopin, 1978) is described from the Kingdom of Saudi Arabia (Rawdhat Khorim, Riyadh Province). This finding represents the first record of the genus Boromorphus Wollaston, 1854 from the Arabian Peninsula. The species was collected from Acacia trees and from pitfall traps.     

pH profiles of 3-chymotrypsin-like protease (3CLpro) from SARS-CoV-2 elucidate its catalytic mechanism and a histidine residue critical for activity

3-Chymotrypsin-like protease (3CLpro) is a promising drug target for coronavirus disease 2019 and related coronavirus diseases because of the essential role of this protease in processing viral polyproteins after infection. Understanding the detailed catalytic mechanism of 3CLpro is essential for designing effective inhibitors of infection by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Molecular dynamics studies have suggested pH-dependent conformational changes of 3CLpro, but experimental pH profiles of SARS-CoV-2 3CLpro and analyses of the conserved active-site histidine residues have not been reported. In this work, pH-dependence studies of the kinetic parameters of SARS-CoV-2 3CLpro revealed a bell-shaped pH profile with 2 pK_a values (6.9 ± 0.1 and 9.4 ± 0.1) attributable to ionization of the catalytic dyad His41 and Cys145, respectively. Our investigation of the roles of conserved active-site histidines showed that different amino acid substitutions of His163 produced inactive enzymes, indicating a key role of His163 in maintaining catalytically active SARS-CoV-2 3CLpro. By contrast, the H164A and H172A mutants retained 75% and 26% of the activity of WT, respectively. The alternative amino acid substitutions H172K and H172R did not recover the enzymatic activity, whereas H172Y restored activity to a level similar to that of the WT enzyme. The pH profiles of H164A, H172A, and H172Y were similar to those of the WT enzyme, with comparable pK_a values for the catalytic dyad. Taken together, the experimental data support a general base mechanism of SARS-CoV-2 3CLpro and indicate that the neutral states of the catalytic dyad and active-site histidine residues are required for maximum enzyme activity.     

Symbiotic nitrogen fixation in eight Acacia senegal provenances in dryland clays of the Blue Nile Sudan estimated by the 15N natural abundance method

The symbiotic biological N₂fixation by Acacia senegal was estimated using the ¹⁵N natural abundance (δ ¹⁵N) procedure on eight provenances collected from different environments and soil types grown in a clay soil in the Blue Nile region, Sudan. Balanites aegyptiaca (a non-legume) was used as a non-N₂-fixing reference plant to allow ¹⁵N-based estimates of the proportion of the Acacia N derived from atmospheric N₂ (N_dfa) to be calculated. Results show variation in leaf δ ¹⁵N between A. senegal and the reference plant and among years. The relative δ ¹⁵N values (‰) were higher in B. aegyptiaca than in the N₂-fixing acacia provenances. Provenances originally collected from clay soils fixed little N in the first year, but the amount fixed increased as the trees aged. All provenances showed a decrease in δ ¹⁵N with age. The N_dfa varied between 24% (Mazmoom provenance) and 61% (Rahad provenance) 4 years after planting. There was no significant difference in δ ¹⁵N between provenance groups based on soil type or rainfall at original growing site. The amount of N_dfa increased significantly with age in all provenances. The above-ground contribution of fixed N to foliage growth in a 4-year-old A. senegal was highest in the Rahad sand–soil provenance (46.7 kg N ha⁻¹) and lowest in the Mazmoom clay-soil provenance (28.7 kg N ha⁻¹). Our study represents the first use of the δ ¹⁵N method for estimating the N input by A. senegal to the clay plain soils of the gum belt in the Sudan.     

Organ transplantation: contemporary Sunni Muslim legal and ethical perspectives

The problems that organ transplantation poses to the Muslim mind may be summarized as follows: firstly, a Muslim believes that whatever he owns or possesses has been given to him as an amanah (trust) from Allah. Would it not be a breach of trust to give consent for the removal of parts of one's body, while still alive, for transplantation to benefit one's child, sibling or parent? Secondly, the Shari'ah (Islamic Law) emphasizes the sacredness of the human body. Would it not then be an act of aggression against the human body, tantamount to its mutilation, if organs were to be removed after death for the purpose of transplantation? In this paper I attempt to illustrate how the Muslim jurists have tried to resolve the dilemma of Muslims by providing them with certain guidelines based on the original sources of Islam, namely, the Qur'an and the Prophetic tradition. In order to assist the followers of other religious traditions to grasp the gravity of the problem posed by organ transplantation to the Muslim mind, I begin by discussing the opinions of Muslim jurists on the issue of utilization of human parts. Thereafter, I touch upon the resolutions taken by the various Islamic Juridical Academies on the issue in question. Finally, I shed light upon the inclusion of organ donation in a Muslim Will and the enforceable nature of such a will.     

Isolation, Purification, and Characterization of an Endogenous Root-promoting Factor Obtained from Basal Sections of Pear Hardwood Cuttings

Basal segments taken from Old Home and Bartlett pear hardwood cuttings collected at intervals during the rooting period in September were extracted with ethanol and fractionated by paper chromatography in different solvent systems. Different zones on the chromatograms were bioassayed by the mung bean rooting test, which showed high levels of promotion in Old Home basal extracts when the cuttings were obtained during the period of maximum rooting. Extracts from Bartlett cuttings, however, showed considerably less promotion activity in the bioassay but did show high levels of inhibitory activity.

After the easily-rooted Old Home cuttings had been in the rooting medium for 10 days, a highly active endogenous root-promoting material was found in extracts from basal segments of cuttings having buds and which had been treated with indolebutyric acid. Similar extracts obtained from disbudded cuttings, or from cuttings with buds but not treated with indolebutyric acid, lacked this rooting-factor. Extracts obtained from all types of the difficult-to-root Bartlett cuttings also lacked this rooting-factor. The latter is believed to be produced by physiologically active Old Home buds, and is very effective in the mung bean bioassay, even at extremely low concentrations.

From paper chromatographic studies, tests with spray reagents, solubility determinations, biological tests, UV spectrum analysis, and infrared spectroscopy, it is believed that this rooting factor could be a condensation product between exogenous auxin (indolebutyric acid) and a phenolic compound produced by physiologically active Old Home pear buds.

     

Identification of a new hemolysin from diarrheal isolate SSU of Aeromonas hydrophila

A clinical strain SSU of Aeromonas hydrophila produces a potent cytotoxic enterotoxin (Act) with cytotoxic, enterotoxic, and hemolytic activities. A new gene, which encoded a hemolysin of 439-amino acid residues with a molecular mass of 49 kDa, was identified. This hemolysin (HlyA) was detected based on the observation that the act gene minus mutant of A. hydrophila SSU still had residual hemolytic activity. The new hemolysin gene (hlyA) was cloned, sequenced, and overexpressed in Escherichia coli. The hlyA gene exhibited 96% identity with its homolog found in a recently annotated genome sequence of an environmental isolate, namely the type strain ATCC 7966 of A. hydrophila subspecies hydrophila. The hlyA gene did not exhibit any homology with other known hemolysins and aerolysin genes detected in Aeromonas isolates. However, this hemolysin exhibited significant homology with hemolysin of Vibrio vulnificus as well as with the cystathionine beta synthase domain protein of Shewanella oneidensis. The HlyA protein was activated only after treatment with trypsin and the resulting hemolytic activity was not neutralizable with antibodies to Act. The presence of the hlyA gene in clinical and water Aeromonas isolates was investigated and DNA fingerprint analysis was performed to demonstrate its possible role in Aeromonas virulence.     

Case study of a biological control: <Emphasis Type="Italic">Geobacillus caldoxylosilyticus</Emphasis> (IRD) contributes to alleviate salt stress in maize (<Emphasis Type="Italic">Zea mays</Emphasis> L.) plants

The inevitable exposure of crop plants to salt stress is a major environmental problem emerged from the presence of excess NaCl radicals in the soil. Handling the problem in maize plants using a biological agent was the main interest of the present study. The non-pathogenic, halophytic, facultative aerobic bacterium Geobacillus caldoxylosilyticus IRD that was isolated from Marakopara pond in the Atoll Tikehau (French Polynesian, 2005) and found tolerant to salt stress until 3.5% NaCl (w/v). An artificial symbiosis was achieved by inoculating Geobacillus sp. into 5-day-old maize cultivars of triple hybrids (321 and 310) and singlet hybrids (10 and 162). Thereafter, maize seedlings were exposed to 350 mmol NaCl for 10 days. The data revealed that Geobacillus sp. had interacted with salinized maize and improved maize overall growth, dry weight and relative water content. Na⁺ accumulation was six times less and Cl⁻ accumulation was 13 times less in the tips of salinized maize seedlings upon Geobacillus sp. inoculation. Salinized maize without Geobacillus viewed decayed cortical cells of seedlings. In addition, proline content was two times higher in salinized seedlings lacking Geobacillus. Photosynthetic pigments and antioxidant enzymes were significantly regulated upon inoculation. Beyond this study, we presented a novel insight into a possible role of Geobacillus caldoxylosilyticus bacteria in controlling/protecting maize plants against high salt stress.     

Cold shock exoribonuclease R (VacB) is involved in Aeromonas hydrophila pathogenesis

In this study, we cloned and sequenced a virulence-associated gene (vacB) from a clinical isolate SSU of Aeromonas hydrophila. We identified this gene based on our recently annotated genome sequence of the environmental isolate ATCC 7966(T) of A. hydrophila and the vacB gene of Shigella flexneri. The A. hydrophila VacB protein contained 798 amino acid residues, had a molecular mass of 90.5 kDa, and exhibited an exoribonuclease (RNase R) activity. The RNase R of A. hydrophila was a cold-shock protein and was required for bacterial growth at low temperature. The vacB isogenic mutant, which we developed by homologous recombination using marker exchange mutagenesis, was unable to grow at 4 degrees C. In contrast, the wild-type (WT) A. hydrophila exhibited significant growth at this low temperature. Importantly, the vacB mutant was not defective in growth at 37 degrees C. The vacB mutant also exhibited reduced motility, and these growth and motility phenotype defects were restored after complementation of the vacB mutant. The A. hydrophila RNase R-lacking strain was found to be less virulent in a mouse lethality model (70% survival) when given by the intraperitoneal route at as two 50% lethal doses (LD(50)). On the other hand, the WT and complemented strains of A. hydrophila caused 80 to 90% of the mice to succumb to infection at the same LD(50) dose. Overall, this is the first report demonstrating the role of RNase R in modulating the expression of A. hydrophila virulence.