Development of some lepidopterous cotton pests as affected by exposure to sublethal levels of endotoxins of Bacillus thuringiensis for different periods

Three spore-δ-endotoxin preparations from Bacillus thuringiensis vars. kurstaki and entomocidus including a commercial biological insecticide, Thuricide, were studied with respect to their biological interactions with the lepidopterous cotton pests, Spodoptera littoralis, Spodoptera exigua, and Heliothis armigera. The biological effects of sublethal doses and the length of exposure time to low endotoxin concentrations were assessed during and after removal of toxin from the diet. Retardation in larval development, reduction in egg production of the moths, and fertility of the egg were observed together with significant reduction in pupal weight and appearance of deformities in both pupae and moth populations. The influence of exposure to sublethal toxin concentrations was also manifested in term of decreasing the adult emergence, fecundity reduction, and prolonging the generation period. In the exposed insects, the precentage of larvae that survived and succeeded to pupate increased with the decrease in the toxin concentration and with the decrease in exposure time. The reduction of the pupal weight significantly increased with the increase in either toxin concentration or the duration of exposure. The longevity of the moths was not affected by larval treatment and the data showed no clear correlation with the concentration and time of larval exposure to the toxin.     

Heat,drought, and combined stress effect on transgenic potato plants overexpressing the StERF94 transcription factor

Journal of Plant Research - Despite their economic importance worldwide, potato plants are sensitive to various abiotic constraints, such as drought and high temperatures, which cause significant...     

Seasonal variations in thalli and carrageenan composition of Gigartina pistillata (Gmelin) Stackhouse (Rhodophyta, Gigartinales) harvested along the Atlantic coast of Morocco

The biology and biochemistry of Gigartina pistillata (Gmelin) Stackhouse collected monthly at Nation Beach (Morocco), was studied during one year. The biological study showed one period of active growth from April to July. The thallus composition was quite stable during the major part of the year. The dry matter was maximum in May and August and minimum in January. The maximum carrageenan content occurred in June and September (about 37%) and the minimum carrageenan content occurred in February (19.0%). The total nitrogen content varied significantly, with a maximum in January (1.98%) and a minimum in August (0.7%). The ash content was significant (23–32%) with a maximum in August and a minimum in May. The carrageenan extracted from natural populations of Gigartina pistillata was a mixture of lambda‐type and kappa‐type carrageenans. The 3,6‐anhydrogalactose varied between 4.5 mol% in June to 25 mol% in February. For industrial applications the extract could be considered as a lambda‐type. The best period for harvest of G. pistillata in Morocco is between July and August when biomass and viscosity are at their maximum. A relationship between the physical characteristics of G. pistillata carrageenans and its seasonal cycle was deduced.     

Assimilation of peptides and amino acids and dissimilation of lactate during submerged pure cultures of Penicillium camembertii and Geotrichum candidum

The behavior of Penicillium camembertii and Geotrichum candidum growing in submerged pure cultures on simple (glutamate) or complex (peptones) substrates as nitrogen and carbon sources and an lactate as a second carbon source was examined. Similar to the behavior previously recorded on a simple substrate (glutamate), a clear differentiation between the carbon source and the energy source was also shown on peptones and lactate during P. camembertii growth, since throughout growth, lactate was only dissimilated, viz., used for energy supply by oxidation into CO2, whereas peptides and amino acids from peptones were used for carbon (and nitrogen) assimilation. Because of its deaminating activity, G. candidum preferred peptides and amino acids to lactate as energy sources, in addition to being assimilated as carbon and nitrogen sources. From this, on peptones and lactate, G. candidum grew faster than P. camembertii (0.19 and 0.08 g/l/h, respectively) by assimilating the most readily utilizable peptides and amino acids; however, owing to its lower proteolytic activity, the maximum biomass was lower than that of P. camembertii (3.7 and 5.5 g/l, respectively), for which continuous proteolysis and assimilation of peptides were shown.     

Intracellular Staphylococcus aureus employs the cysteine protease staphopain A to induce host cell death in epithelial cells

Staphylococcus aureus is a major human pathogen, which can invade and survive in non-professional and professional phagocytes. Uptake by host cells is thought to contribute to pathogenicity and persistence of the bacterium. Upon internalization by epithelial cells, cytotoxic S. aureus strains can escape from the phagosome, replicate in the cytosol and induce host cell death. Here, we identified a staphylococcal cysteine protease to induce cell death after translocation of intracellular S. aureus into the host cell cytoplasm. We demonstrated that loss of staphopain A function leads to delayed onset of host cell death and prolonged intracellular replication of S. aureus in epithelial cells. Overexpression of staphopain A in a non-cytotoxic strain facilitated intracellular killing of the host cell even in the absence of detectable intracellular replication. Moreover, staphopain A contributed to efficient colonization of the lung in a mouse pneumonia model. In phagocytic cells, where intracellular S. aureus is exclusively localized in the phagosome, staphopain A did not contribute to cytotoxicity. Our study suggests that staphopain A is utilized by S. aureus to exit the epithelial host cell and thus contributes to tissue destruction and dissemination of infection.     

The use of previous crops as sustainable and eco-friendly management to fight Fusarium oxysporum in sesame plants

Sesame (Sesamum indicum L.), the “Queen of oil seeds” is being infected with pathogens, i.e., fungi, bacteria, virus and nematodes. Fusarium oxysporum sp. sesami (Zap.), is one of the fiercest pathogens causing severe economic losses on sesame. This work aimed to evaluate the impact of the cultivation of some preceding crops and seed inoculation with antagonistic predominant rhizospheric bacteria and actinomycetes on the incidence and development of Fusarium damping-off and wilt disease. Results showed that the lowest pre and/or post-emergence damping-off and wilt of sesame were recorded after onion and garlic, followed by wheat compared to clover in both the 2019 and 2020 seasons. In vitro, soil extracts from plots where onion and garlic have been cultivated slightly decreased the conidia germination and mycelium radial growth of F. oxysporum. The numbers of sesame rhizospheric F. oxysporum and fungi were lower after the cultivation of onion and garlic than those after wheat and clover. However, the numbers of actinomycetes and bacteria were higher in the onion, garlic, and clover rhizosphere than wheat. Among all isolated bacteria and actinomycetes associated with sesame roots cultivated after preceding plants, the Tricoderma viride and Bacillus subtilis (isolate No.3) profoundly reduce F. oxysporum mycelial growth in vitro. When sesame seeds were inoculated with Tricoderma viride, Bacillus subtilis, Streptomyces rochei and Pseudomonas fluorescens, the disease incidence of damping-off and wilt significantly decreased in the greenhouse and field trials conducted in both tested growing seasons, also had highly significant on plant health and growth parameters. Therefore, the current study suggested that using the preceding onion and garlic plants could be used for eco-friendly reduction of damping-off and wilt disease of sesame.     

Value of histiocyte detection in Pap smears for predicting endometrial pathology. An institutional experience

OBJECTIVE: To determine the clinical implications of the finding of histiocytes in Pap smears in 1 patient population. STUDY DESIGN: The medical records and Pap smears which the presence of histiocytes was mentioned in the diagnosis between August 1996 and August 2001 were reviewed in conjunction with follow-up surgical findings. The positive predictive value (PPV) for significant endometrial pathology for the isolated finding of histiocytes on Pap smear was determined. RESULTS: Of the 238,225 women screened over a 60-month period, 325 were reported to have histiocytes in their Pap smears. Of them, 238 (73.2%) had subsequent endometrial sampling, hysterectomy or both, and follow-up Pap smears. Two hundred seven smears (87%) failed to disclose endometrial pathology. Thirty-one cases (13%) resulted in significant histopathologic findings, including 12 uterine malignancies, 8 endocervical polyps, 7 endometrial polyps, 2 submucosal leiomyomata, 1 simple hyperplasia without atypia and 1 case of tamoxifen-related changes. Upon review of the clinical records, 58% (18/31) of those patients had other significant clinical and/or cytologic findings. Five of the 18 patients (27.8%) had associated postmenopausal bleeding, 11 had additional abnormal Pap smear findings (atypical glandular cells, 6/18, or 33.3%; endometrial cells, 5/18, or 27.8%), and another 2 had both postmenopausal bleeding and atypical glandular cells (2/18, or 11.1%). The PPV for significant uterine pathology for women with the isolated finding of histiocytes on a Pap smear was 5.5% and 60% with additional clinical and/or Pap smear findings. The PPV for endometrial cancer was 1.3% in women with the isolated finding of histiocytes on a Pap smear but 20% for women with histiocytes and additional clinical/or Pap smear findings. CONCLUSION: Based on the findings of this study and recently published data, we conclude that the isolated finding of increased histiocytes in the absence of postmenopausal bleeding, endometrial cells or atypical glandular cells on a Pap smear is a poor indicator of uterine disease.     

Action Potential Clamp and Pharmacology of the Variant 1 Short QT Syndrome T618I hERG K+ Channel

Background

The familial Short QT Syndrome (SQTS) is associated with an increased risk of cardiac arrhythmia and sudden death. Gain-of-function mutations in the hERG K⁺ channel protein have been linked to variant 1 of the SQTS. A hERG channel pore (T618I) mutation has recently been identified in families with heritable SQTS. This study aimed to determine effects of the T618I-hERG mutation on (i) hERG current (I_hERG) elicited by ventricular action potentials; (ii) the sensitivity of I_hERG to inhibition by four clinically used antiarrhythmic drugs.

Methods

Electrophysiological recordings of I_hERG were made at 37°C from HEK 293 cells expressing wild-type (WT) or T618I hERG. Whole-cell patch clamp recording was performed using both conventional voltage clamp and ventricular action potential (AP) clamp methods.

Results

Under conventional voltage-clamp, WT I_hERG peaked at 0-+10 mV, whilst for T618I I_hERG maximal current was right-ward shifted to ∼ +40 mV. Voltage-dependent activation and inactivation of T618I I_hERG were positively shifted (respectively by +15 and ∼ +25 mV) compared to WT I_hERG. The I_hERG ‘window’ was increased for T618I compared to WT hERG. Under ventricular AP clamp, maximal repolarising WT I_hERG occurred at ∼ -30 mV, whilst for T618I hERG peak I_hERG occurred earlier during AP repolarisation, at ∼ +5 mV. Under conventional voltage clamp, half-maximal inhibitory concentrations (IC₅₀) for inhibition of I_hERG tails by quinidine, disopyramide, D-sotalol and flecainide for T618I hERG ranged between 1.4 and 3.2 fold that for WT hERG. Under action potential voltage clamp, T618I IC₅₀s ranged from 1.2 to 2.0 fold the corresponding IC₅₀ values for WT hERG.

Conclusions

The T618I mutation produces a more modest effect on repolarising I_hERG than reported previously for the N588K-hERG variant 1 SQTS mutation. All drugs studied here appear substantially to retain their ability to inhibit I_hERG in the setting of the SQTS-linked T618I mutation.