Agrobacterium tumefaciens can transfer a DNA fragment (T-DNA) from its Ti plasmid to host plant and integrate the T-DNA fragment into host cell nuclear genome. Agrobacterium-mediated T-DNA transfer is the most widely used genetic transformation method for plant. The T-DNA is delivered in the form of single-stranded T-DNA-protein complex (T-complex) by the polar-located Agrobacterium type Ⅳ secretion system (T4SS) to the host cell. T4SS is ancestrally related to bacterial conjugation machines and still used by many plasmids as conjugation channel. Moreover, T4SS is also the secretion channel that used by many human bacterial pathogens to inject the effector proteins to host cells, thus contributing directly to the bacterial pathogenicity. Therefore, in addition to the technical application as a gene vector to create transgenic plants, Agrobacterium-mediated T-DNA transfer also provides a fascinating model system to study the intercellular transfer of macromolecules. The study on the molecular mechanism of T-DNA transfer arouses extensive interest and progresses rapidly in recent years. Here the recent advances in research on T-complex formation and T-complex transfer in Agrobacterium cell are reviewed.

Objective To investigate the clinical features of Parkinson disease (PD)with constipation.Methods From October 2013 to August 2015,a total of 204 PD patients were consecutively recruited from the Departments of Geriatrics and Neurology,Beijing Tiantan Hospital,Capital Medical University,and were evaluated by Rome Ⅲ diagnostic criteria for functional constipation and other related scales of motor symptoms(MS)and non-motor symptoms(NMS),the activity of daily living(ADL)and quality of life.Results Overall,131 of 204(64.2％)PD patients with constipation were assigned to the PD-C group and 73 of 204 (35.8％)PD patients without constipation were assigned to the PD-NC group.In the PD-C group,38 of 131(29％)PD patients had constipation before motor symptoms occurred.The mean age and age of onset in the PD-C group were significantly older than those in the PD-NC group (64.13 ± 9.67 vs.58.35 ± 11.37;60.07 ± 10.46 vs.55.10±12.97;F=2.287,4.948;t=3.827,-2.788;P＜0.01 for both).Meanwhile,compared with the PD-NC group,the PD-C group was associated with dramatically longer disease duration (2.25,range:1.00-5.00 vs.2.00,range:1.00-3.13;Z =-2.254;P ＜ 0.05),increased scores of the Unified Parkinson Disease Rating Scale (UPDRS) Ⅲ (26.00 scores,range:18.00 37.50 vs.19.00,range:12.50-31.00;Z =-2.349,P ＜ 0.05),more advanced stages on the Hoehn-Yahr (H-Y) scale (2.00 stage,range:1.50-2.50 vs.1.50,range:1.00-2.50;Z=-2.334,P＜0.05),higher total numbers of NMS(11.00,range:6.00-15.00 vs.6.00,range:3.00-11.00;Z=-3.715,P＜0.05),and higher numbers of NMS occurring before and after MS(before,2.00,range:0.00-4.00 vs.1.00,range:0.00-2.00;after,8.00,range:3.00-14.00 vs.5.00,range:2.00-9.50;Z =-2.612,-2.630,respectively;P＜0.05 for both).Additionally,there were significant differences between the groups in the scores of the Hamilton depression scale (HAMD),the Hamilton anxiety scale (HAMA),the Pittsburgh sleep quality index (PSQI),the scales for outcomes in Parkinson disease-autonomic (SCOPA-AUT),the Fatigue severity scale (FSS),the Apathy scale,the Montreal Cognitive Assessment(MoCA)scale,the UPDRS Ⅱ and ADL Scale,and the PDQL-39 (all P＜0.05).Binary Logistic regression analysis showed that age,SCOPA-AUT,HAMA and HAMD were risk factors for PD-C(OR=1.091,1.107,1.10 and 1.080;P＜0.05 for all).Conclusions PD patients have a high incidence of constipation,and more than a quarter of patients have constipation before MS occurs.Meanwhile,PD patients with constipation are usually associated with old age and late age of onset,long disease duration,severe MS,frequent and severe NMS,bad cognition,emotional state and sleep,severe fatigue,and apathy.Moreover,advanced age,autonomic dysfunction,anxiety and depression increase the risk of PD with constipation.Constipation has a serious negative impact on the activity of daily living and quality of life in PD patients.

OBJECTIVE: To investigate the perioperative electrolyte imbalance in patients undergoing gastrointestinal surgery. METHODS: Retrospective case analysis was used in this study. Patients who underwent gastrointestinal surgery under general anesthesia at the Sixth Affiliated Hospital of Sun Yat-sen University from January to April 2018 were selected through electronic medical records system. Blood gas analysis during surgery must be carried out in the enrolled patients. Patients with excessive fluid infusion, critical conditions or patients who had been enrolled in other clinical trials were excluded. A total of 999 patients were enrolled. The preoperative, intraoperative and postoperative concentrations of serum sodium, potassium and calcium were collected by the last biochemical examination before surgery, arterial blood gas analysis within 1 h after anesthesia and another biochemical examination within 24 hours after surgery respectively. The type and incidence of electrolyte imbalance were then analyzed, and logistic regression analysis was used to investigate the risk factors. RESULTS: In the 999 patients, 683 cases were male (63.9%) and 361 cases were female(36.1%), with an average age of (56.9±14.6) years old. Fifty-eight patients (5.8%) underwent emergency surgery and 941 patients (94.2%) underwent elective surgery; Sixty-two patients were treated with laxatives at least 3 times and 115 patients were treated with enema at least 3 times before operation. The incidence of hypokalemia was 49.6%(496/999) intraoperatively and decreased to 15.2%(152/999) postoperatively. No hyperkalemia cases were found. The incidence of hypocalcemia was 53.8%(537/999) intraoperatively and increased to 79.7% (796/999) postoperatively. The incidence of hypokalemia in ileus patients was 33.3%(17/51) before surgery, which was higher than that in patients with colorectal cancer [12.3%(86/703)], patients with gastric cancer [7.8%(8/104)] and patients with other gastrointestinal diseases[10.6%(15/141)] (all P<0.05). Similarly, the preoperative and intraoperative incidence of hyponatremia in ileus patients were both 15.7%(8/51), which were higher than those in patients with colorectal cancer [3.0% (21/703) and 2.3% (16/703)] and patients with gastric cancer [2.9%(3/104) and 1.9%(2/104)]. The incidence of hypocalcemia in ileus patients was 31.4%(16/51) preoperatively, which were also higher than those in patients with colorectal cancer [7.4%(52/703)] and patients with gastric cancer [8.7%(9/104)] (all P<0.05). Logistic regression analysis showed that ileus and emergency surgery were risk factors for patients with preoperative electrolyte imbalance; preoperative electrolyte imbalance was a risk factor for intraoperative electrolyte imbalance; intraoperative electrolyte imbalance was a risk factor for postoperative electrolyte imbalance; preoperative electrolyte imbalance was a risk factor for postoperative imbalance of sodium and potassium. CONCLUSIONS The incidence of electrolyte imbalance is high in patients undergoing gastrointestinal surgery, especially hypocalcemia and hypokalemia. It is necessary to recognize the electrolyte abnormality timely and give active intervention and correction.
Adult ; Aged ; Digestive System Surgical Procedures ; Electrolytes ; Female ; Humans ; Hyponatremia ; Ileus ; Male ; Middle Aged ; Postoperative Complications ; prevention & control ; Retrospective Studies ; Risk Factors ; Water-Electrolyte Imbalance